阅读说明：本技术 轧机和轧机的设定方法 (Rolling mill and setting method of rolling mill ) 是由 石井笃 河西大辅 新国大介 于 2019-05-17 设计创作，主要内容包括：一种轧机,是具备多个辊的4辊以上的轧机,多个辊至少包括一对作业辊和支承作业辊的一对加强辊,在轧机中,将在压下方向上排列的各辊中的任一个辊设为基准辊,轧机具备：荷重检测装置,其在加强辊的作业侧和驱动侧的压下支点位置,检测作用于辊的压下方向上的压下方向荷重；按压装置,其至少针对基准辊以外的辊的辊轴承座,设置于轧制方向入侧和轧制方向出侧中的任一方,在轧制方向上按压辊轴承座；驱动装置,其至少针对基准辊以外的辊的辊轴承座,以在轧制方向上与按压装置相向的方式设置,使辊轴承座在轧制方向上移动；以及位置控制装置,其将基准辊的辊轴承座的轧制方向位置作为基准位置进行固定,对驱动装置进行驱动,来控制基准辊以外的辊的辊轴承座在轧制方向上的位置。(A rolling mill having a plurality of rolls, including at least a pair of work rolls and a pair of reinforcing rolls for supporting the work rolls, the rolling mill having any one of the rolls arranged in a rolling direction as a reference roll, the rolling mill comprising 4 or more rolls: a load detection device for detecting a load in a pressing direction acting on the roller at positions of pressing fulcrums on a working side and a driving side of the reinforcing roller; a pressing device which is provided on at least one of the rolling direction entry side and the rolling direction exit side with respect to the roll bearing housing of the roll other than the reference roll, and presses the roll bearing housing in the rolling direction; a drive device which is provided at least for the roller bearing seat of the roller other than the reference roller so as to face the pressing device in the rolling direction and moves the roller bearing seat in the rolling direction; and a position control device for fixing the rolling direction position of the roll chocks of the reference roll as a reference position, and driving the drive device to control the positions of the roll chocks of the rolls other than the reference roll in the rolling direction.)

1. A rolling mill having 4 or more rolls including at least a pair of work rolls and a pair of reinforcing rolls for supporting the work rolls, wherein the rolling mill,

any one of the rollers arranged in the pressing-down direction is set as a reference roller,

the rolling mill is provided with:

a load detection device for detecting a load acting in a pressing direction of the roller at positions of pressing fulcrums on a working side and a driving side of the reinforcing roller;

a pressing device provided on at least one of a rolling direction entry side and a rolling direction exit side of the material to be rolled with respect to the roll bearing housing of the roll other than the reference roll, the pressing device pressing the roll bearing housing in the rolling direction;

a drive device that is provided at least for the roller bearing blocks of the rollers other than the reference roller so as to face the pressing device in the rolling direction, and that moves the roller bearing blocks in the rolling direction; and

and a position control device that fixes a rolling direction position of a roll chock of the reference roll as a reference position, and drives the drive device to control a position of the roll chock of the roll other than the reference roll in the rolling direction so that a rolling direction load difference, which is a difference between the rolling direction load detected by the load detection device on the work side and the rolling direction load detected by the load detection device on the drive side, is within an allowable range.

2. The rolling mill of claim 1,

the lowermost or uppermost roller of the plurality of rollers in the depressing direction is set as the reference roller.

3. The rolling mill of claim 1 or 2,

a bending device for applying a bending force to the roller,

the position control device sets a nip between the working rolls to an open state, and applies a bending force to the roll bearing block on the roll side to be subjected to the position adjustment by the bending device.

4. The rolling mill of any one of claims 1 to 3,

the driving device is a hydraulic cylinder provided with a roller bearing seat position detecting device.

5. A setting method of a rolling mill, wherein,

the rolling mill is a 4-roll or more rolling mill including a plurality of rolls including at least a pair of work rolls and a pair of reinforcing rolls supporting the work rolls, and a load detection device for detecting a load in a reduction direction acting on the rolls at positions of reduction support points on a working side and a driving side of the reinforcing rolls,

the setting method of the rolling mill is implemented before the zero point adjustment of the rolling position or before the rolling is started,

in the setting method of the rolling mill described above,

any one of the rollers arranged in the pressing-down direction is set as a reference roller,

calculating a load difference in a depressing direction, which is a difference between the load in the depressing direction detected by the load detecting means on the working side and the load in the depressing direction detected by the load detecting means on the driving side,

the positions of the roll chocks are adjusted so that the rolling direction load difference is within an allowable range by fixing the rolling direction position of the roll chock of the reference roll as a reference position and moving the roll chocks of the rolls other than the reference roll in the rolling direction of the material to be rolled.

6. The setting method of a rolling mill according to claim 5,

the lowermost or uppermost roller of the plurality of rollers in the depressing direction is set as the reference roller.

7. The setting method of a rolling mill according to claim 6,

in the 4-roll rolling mill described above,

a plurality of rolls disposed on the upper side in the rolling direction with respect to the material to be rolled are set as an upper roll system, a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system,

a first step of adjusting positions of the upper roll system and the lower roll system between the roll chocks of the work rolls and the roll chocks of the reinforcing rolls, respectively, while a nip of the work rolls is opened and a bending force is applied to the roll chocks of the work rolls by a bending device,

after the first step is completed, a second step is performed in which the positions of the roll chocks of the upper roll system and the lower roll system are adjusted by bringing the work rolls into contact with each other,

in the first step, the following steps are carried out:

a first reference value calculation step of rotating the roller in a predetermined rotation direction, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a first reference value based on a pressing-down direction load difference that is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side;

a first control target value calculation step of reversing a rotation direction of the roller, detecting a pressing direction load on a working side and a driving side for each of the upper roller system and the lower roller system, and calculating a first control target value based on a deviation between a pressing direction load difference on the working side and a pressing direction load on the driving side and the first reference value; and

a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving the roll chocks of the work rolls of the roll system on the reference roll side or the work rolls of the roll system on the opposite side of the reference roll or the roll chocks of the reinforcing rolls in the rolling direction,

in the second step, the work roller is set in a roller contact state,

in the second step, the following steps are carried out:

a second reference value calculation step of rotating the roller in a predetermined rotation direction, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a second reference value based on a pressing-down direction load difference that is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side;

a second control target value calculation step of reversing the rotation direction of the roller, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a second control target value based on a deviation between a pressing-down direction load difference between the working side pressing-down direction load and the driving side pressing-down direction load and the second reference value; and

and a second adjustment step of adjusting the positions of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the second control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

8. The setting method of a rolling mill according to claim 6,

in the 6-roll rolling mill having the intermediate rolls between the work rolls and the reinforcing rolls,

a plurality of rolls disposed on the upper side in the rolling direction with respect to the material to be rolled are set as an upper roll system, a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system,

a first step of adjusting positions of the upper roll system and the lower roll system between the roll chocks of the intermediate roll and the roll chocks of the reinforcing roll, respectively, while a nip of the work roll is opened and a bending force is applied to the roll chocks of the intermediate roll by a bending device,

after the first step is completed, performing a second step of adjusting positions between the roll chocks of the intermediate roll and the roll chocks of the work rolls for the upper roll system and the lower roll system, respectively, while maintaining the roll gap of the work rolls in an open state and applying a bending force to the roll chocks of the work rolls by a bending device,

after the second step is completed, a third step is performed in which the positions of the roll chocks of the upper roll system and the lower roll system are adjusted by bringing the work rolls into contact with each other,

in the first step, the following steps are carried out:

a first reference value calculation step of rotating the roller in a predetermined rotation direction, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a first reference value based on a pressing-down direction load difference that is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side;

a first control target value calculation step of reversing a rotation direction of the roller, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a first control target value based on a deviation of a pressing-down direction load difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side from the first reference value; and

a first adjustment step of adjusting a position of the roll chocks so that the rolling direction load difference is within an allowable range of the first control target value by moving one of the roll chocks of the intermediate roll and the roll chock of the reinforcing roll of the roll system on the side opposite to the reference roll and the roll chock of the intermediate roll of the roll system on the side of the reference roll in the rolling direction,

in the second step, the following steps are carried out:

a second reference value calculation step of rotating the roller in a predetermined rotation direction, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a second reference value based on a pressing-down direction load difference that is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side;

a second control target value calculation step of reversing the rotation direction of the roller, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a second control target value based on a deviation between a pressing-down direction load difference between the working side pressing-down direction load and the driving side pressing-down direction load and the second reference value; and

a second adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference is within an allowable range of the second control target value by moving the roll chocks of the work roll of the roll system on the opposite side of the reference roll, one of the roll chocks of the intermediate roll and the reinforcing roll, and the roll chock of the work roll of the roll system on the reference roll side in the rolling direction,

in the third step, the work roller is set in a roller contact state,

in the third step, the following steps are carried out:

a third reference value calculation step of rotating the roller in a predetermined rotation direction, detecting a pressing-down direction load on a working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a third reference value based on a pressing-down direction load difference that is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side;

a third control target value calculation step of reversing the rotation direction of the roller, detecting the pressing-down direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a third control target value based on a deviation between a pressing-down direction load difference between the working side pressing-down direction load and the driving side pressing-down direction load and the third reference value; and

and a third adjustment step of adjusting the positions of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the third control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

9. The setting method of a rolling mill according to claim 6,

in the 4-roll rolling mill described above,

a plurality of rolls disposed on the upper side in the rolling direction with respect to the material to be rolled are set as an upper roll system, a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system,

a first step of adjusting positions of the upper roll system and the lower roll system between the roll chocks of the work rolls and the roll chocks of the reinforcing rolls, respectively, while a nip of the work rolls is opened and a bending force is applied to the roll chocks of the work rolls by a bending device,

after the first step is completed, a second step is performed in which the positions of the roll chocks of the upper roll system and the lower roll system are adjusted by bringing the work rolls into contact with each other,

in the first step, the following steps are carried out:

a first control target value calculation step of detecting a depressing direction load on a working side and a depressing direction load on a driving side with respect to the upper roller system and the lower roller system, respectively, in a state where rotation of the roller is stopped, calculating a first reference value based on a depressing direction load difference, which is a difference between the depressing direction load on the working side and the depressing direction load on the driving side, and setting a first control target value based on the first reference value;

a first load difference calculation step of rotating the roller, detecting a pressing direction load on the working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side; and

a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving the roll chocks of the work rolls of the roll system on the reference roll side or the work rolls of the roll system on the opposite side of the reference roll or the roll chocks of the reinforcing rolls in the rolling direction,

in the second step, the work roller is set in a roller contact state,

in the second step, the following steps are carried out:

a second control target value calculation step of detecting the load in the pressing direction on the working side and the load in the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a second reference value based on a difference in the load in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side, and setting a second control target value based on the second reference value;

a second load difference calculation step of rotating the roller, detecting a pressing direction load on the working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side; and

and a second adjustment step of adjusting the positions of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the second control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

10. The setting method of a rolling mill according to claim 6,

in the 6-roll rolling mill having the intermediate rolls between the work rolls and the reinforcing rolls,

a plurality of rolls disposed on the upper side in the rolling direction with respect to the material to be rolled are set as an upper roll system, a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system,

a first step of adjusting positions of the upper roll system and the lower roll system between the roll chocks of the intermediate roll and the roll chocks of the reinforcing roll, respectively, while a nip of the work roll is opened and a bending force is applied to the roll chocks of the intermediate roll by a bending device,

after the first step is completed, performing a second step of adjusting positions between the roll chocks of the intermediate roll and the roll chocks of the work rolls for the upper roll system and the lower roll system, respectively, while maintaining the roll gap of the work rolls in an open state and applying a bending force to the roll chocks of the work rolls by a bending device,

after the second step is completed, a third step is performed in which the positions of the roll chocks of the upper roll system and the lower roll system are adjusted by bringing the work rolls into contact with each other,

in the first step, the following steps are carried out:

a first control target value calculation step of detecting a depressing direction load on a working side and a depressing direction load on a driving side with respect to the upper roller system and the lower roller system, respectively, in a state where rotation of the roller is stopped, calculating a first reference value based on a depressing direction load difference, which is a difference between the depressing direction load on the working side and the depressing direction load on the driving side, and setting a first control target value based on the first reference value;

a first load difference calculation step of rotating the roller, detecting a pressing direction load on the working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side; and

a first adjustment step of adjusting a position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving one of the roll chocks and the reinforcing roll of the intermediate roll of the roll system on the side opposite to the reference roll and the roll chock of the intermediate roll of the roll system on the side of the reference roll in the rolling direction,

in the second step, the following steps are carried out:

a second control target value calculation step of detecting the load in the pressing direction on the working side and the load in the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a second reference value based on a difference in the load in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side, and setting a second control target value based on the second reference value;

a second load difference calculation step of rotating the roller, detecting a pressing direction load on the working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side; and

a second adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference is within an allowable range of the second control target value by moving the roll chocks of the work rolls of the roll system on the opposite side of the reference roll, one of the roll chocks of the intermediate rolls and the reinforcing rolls, and the roll chocks of the work rolls of the roll system on the reference roll side in the rolling direction,

in the third step, the work roller is set in a roller contact state,

in the third step, the following steps are carried out:

a third control target value calculation step of detecting the pressing direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where rotation of the roller is stopped, calculating a third reference value from a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side, and setting a third control target value based on the third reference value;

a third load difference calculation step of rotating the roller, detecting a pressing direction load on the working side and a driving side for the upper roller system and the lower roller system, respectively, and calculating a pressing direction load difference, which is a difference between the pressing direction load on the working side and the pressing direction load on the driving side; and

and a third adjustment step of adjusting the positions of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the third control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

Technical Field

The present invention relates to a rolling mill for rolling a material to be rolled and a method of setting the rolling mill.

Background

In the hot rolling process, as a phenomenon causing a pass failure, for example, meandering of a steel sheet occurs. One of the main causes of meandering of the steel sheet is thrust force generated by minute intersection between rolls of the rolling device (also referred to as roll skew), but it is difficult to directly measure the thrust force. Therefore, conventionally, it has been proposed to measure a thrust reaction force detected as a reaction force that is a total value of thrust forces generated between the rolls, or to measure an intersection angle between the rolls that causes the thrust force, and to recognize the thrust force generated between the rolls based on the thrust reaction force or the intersection angle, thereby performing meandering control of the steel sheet.

For example, patent document 1 discloses a plate rolling method in which: the thrust reaction force in the roll axis direction and the load in the rolling direction are measured, either one or both of the zero point of the rolling position and the deformation characteristics of the rolling mill are determined, and the rolling position is set and rolling control is performed during rolling. Further, patent document 2 discloses a hunting control method including: the roll-down leveling control is performed by calculating a thrust force generated in the rolls based on a minute intersection (skew angle) between the rolls measured by a distance sensor provided inside the rolling mill, calculating a differential load component causing meandering from a load measurement value in the roll-down direction based on the thrust force, and performing roll-down leveling control. Further, patent document 3 discloses an intersection correction device for correcting a deviation of a point (intersection) where the center axes of the upper and lower rolls of the pair of cross rolling mills intersect in the horizontal direction. The device includes an actuator for absorbing a clearance generated between the crosshead and the roller bearing block, and a detector for detecting the position of the roller bearing block, and corrects the deviation of the intersection point based on the position of the roller bearing block.

Further, patent document 4 discloses a method for controlling a rolling mill, the method including: when the load difference between the driving side and the operating side is detected and the rolling positions of the driving side and the operating side are independently operated based on the detected load difference to control the meandering of the rolled material, the differential load due to the thrust force during rolling is estimated to separate the differential load during rolling into the differential load due to the meandering of the rolled material and the differential load due to the thrust force, and the rolling positions of the driving side and the operating side are operated based on the separated differential loads.

Documents of the prior art

Patent document

Patent document 1: japanese patent No. 3499107

Patent document 2: japanese patent laid-open No. 2014-4599

Patent document 3: japanese laid-open patent publication No. 8-294713

Patent document 4: japanese patent No. 4962334

Disclosure of Invention

Problems to be solved by the invention

However, in the technique described in patent document 1, the thrust reaction force of the rolls other than the reinforcing roll needs to be measured during the rolling and during the rolling when the rolling position is adjusted to zero, but when the thrust reaction force is measured during the rolling, the characteristics such as the acting point of the thrust reaction force may change due to a change in the rolling conditions such as the rolling load, and the asymmetric deformation associated with the thrust cannot be accurately specified. Therefore, the press-down leveling control may not be accurately implemented.

In the technique described in patent document 2, the roll skew angle is determined from the horizontal distance of the roll measured by a distance sensor of an eddy current type or the like. However, since the roll is vibrated in the horizontal direction by machining accuracy such as eccentricity or cylindricity of the long portion of the roll body and the position of the horizontal bearing seat is varied by impact or the like at the time of biting at the start of rolling, it is difficult to accurately measure the horizontal displacement of the roll due to the thrust. In addition, since the roughness of the rolls changes with time as the number of rolls increases, the friction coefficient of the rolls changes from time to time. Therefore, the thrust force cannot be accurately calculated by performing only the roll skew angle measurement without determining the friction coefficient.

Further, in the technique described in patent document 3, since the crossing angle between the rolls is generated by the relative crossing of the rolls and there is a gap in the roll bearings and the like, even if the positions of the respective roll bearings are controlled in the rolling direction, the shift in the relative positional relationship of the rolls themselves cannot be eliminated. Therefore, the thrust force generated by the intersection angle between the rollers cannot be eliminated.

In the technique described in patent document 4, before rolling, the rolls are driven in a state where the upper and lower rolls are not in contact with each other, and a bending force is applied, and a differential load due to a thrust force is estimated from a thrust coefficient or a deflection amount obtained based on a load difference between the driving side and the working side generated at that time. In patent document 4, the thrust coefficient or the skew amount is recognized from only the measurement value in one rotation state of the upper and lower rollers. Therefore, when the zero point of the load detection device is shifted or the influence of the frictional resistance between the housing and the roller bearing housing is different from each other in the left and right directions, an asymmetric error may occur between the measurement value on the drive side and the measurement value on the work side. In particular, when the load level is small such as a bending force, the error may become a critical error in identifying the thrust coefficient or the deflection amount.

In patent document 4, if the friction coefficient between the rollers is not provided, the thrust coefficient or the skew amount cannot be recognized. In patent document 4, the thrust reaction force of the support roller acts on the roller axial center position, and the change in the position of the action point of the thrust reaction force is not considered. Since the bearing seat of the support roller is usually supported by a screw-down device or the like, the point of action of the thrust reaction force is not limited to the position on the roller axis. Therefore, an error occurs in the thrust between the rollers obtained from the load difference between the driving-side load in the rolling direction and the working-side load in the rolling direction, and an error also occurs in the thrust coefficient or the skew amount calculated based on the thrust between the rollers. If an error occurs in the thrust coefficient or the skew amount in this manner, the accuracy of the meandering control of the rolled material is reduced due to the influence of the error.

In addition, as a preparation operation before the normal rolling, after the work rolls are rearranged, the operator adjusts the zero point of the rolling position in the roll contact state based on the values of the work side and the drive side of the load in the rolling direction. In this case, if the inter-roller thrust is generated by a minute intersection between the rollers, a difference may be generated between the driving side and the working side due to the depressing direction load, and the depressing position zero point adjustment may not be performed accurately. However, in any of the techniques described in the above-described patent documents, the inter-roller thrust cannot be reduced before the adjustment of the depression position zero point.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a new and improved rolling mill and a method of setting a rolling mill, which can suppress the occurrence of meandering and warping of a material to be rolled by reducing a thrust force generated between rolls before a rolling position zero point is adjusted or before rolling is started.

Means for solving the problems

In order to solve the above problems, according to an aspect of the present invention, there is provided a rolling mill having 4 or more rolls including a plurality of rolls including at least a pair of work rolls and a pair of reinforcing rolls supporting the work rolls, wherein any one of the rolls arranged in a rolling direction is used as a reference roll, the rolling mill comprising: a load detection device for detecting a load in a pressing direction acting on the roller at positions of pressing fulcrums on a working side and a driving side of the reinforcing roller; a pressing device which is provided on at least one of a rolling direction entry side and a rolling direction exit side of the material to be rolled with respect to the roll bearing housing of the roll other than the reference roll, and presses the roll bearing housing in the rolling direction; a drive device which is provided at least for the roller bearing seat of the roller other than the reference roller so as to face the pressing device in the rolling direction and moves the roller bearing seat in the rolling direction; and a position control device for fixing the rolling direction position of the roll chocks of the reference roll as a reference position, and driving the drive device to control the positions of the roll chocks of the rolls other than the reference roll in the rolling direction so that a rolling direction load difference, which is a difference between the rolling direction load detected by the load detection device on the work side and the rolling direction load detected by the load detection device on the drive side, is within an allowable range.

The lowermost or uppermost roller of the plurality of rollers in the pressing direction may be set as the reference roller.

Further, a bending device that applies a bending force to the roller may be provided. At this time, the position control device opens the nip between the work rolls, and the bending device applies a bending force to the work roll chock on the roll side to be position-adjusted.

The driving device may be a hydraulic cylinder provided with a roller bearing seat position detecting device.

In order to solve the above-mentioned problems, according to another aspect of the present invention, there is provided a method of setting a rolling mill which is a 4-roll or more rolling mill including a plurality of rolls including at least a pair of work rolls and a pair of reinforcing rolls supporting the work rolls, and a load detection device for detecting a rolling load acting in a rolling direction of the rolls at positions of rolling points on a work side and a drive side of the reinforcing rolls, wherein the method of setting the rolling mill is performed before a rolling position zero point adjustment or before start of rolling, wherein a rolling direction load difference is calculated by setting any one of the rolls arranged in the rolling direction as a reference roll, the rolling direction load difference being a difference between the rolling direction load detected by the load detection device on the work side and the rolling direction load detected by the load detection device on the drive side, the position of the roll chocks is adjusted so that the rolling direction load difference is within an allowable range by fixing the rolling direction position of the roll chocks of the reference rolls as a reference position and moving the roll chocks of the rolls other than the reference rolls in the rolling direction of the material to be rolled.

The lowermost or uppermost roller of the plurality of rollers in the pressing direction may be set as the reference roller.

In a 4-roll rolling mill, a first step may be performed in which a plurality of rolls provided on an upper side in a rolling direction with respect to a material to be rolled are set as an upper roll system and a plurality of rolls provided on a lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system, a position between a roll chock of a work roll and a roll chock of a reinforcing roll is adjusted for each of the upper roll system and the lower roll system in a state where a roll gap of the work roll is opened and a bending force is applied to the roll chock of the work roll by a bending device, a second step may be performed after the first step is completed, the position of the roll chock of the upper roll system and the position of the roll chock of the lower roll system are adjusted in a second step in which the work rolls are brought into contact with each other, and the following steps may be performed in the first step: a first reference value calculation step of rotating the roller in a predetermined rotation direction, detecting the load in the depressing direction on the working side and the load in the depressing direction on the driving side for each of the upper roller system and the lower roller system, and calculating a first reference value based on a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side; a first control target value calculation step of reversing the rotation direction of the roller, detecting the pressing direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a first control target value based on a deviation between a pressing direction load difference, which is a difference between the pressing direction load of the working side and the pressing direction load of the driving side, and a first reference value; and a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving the roll chocks of the work rolls of the roll system on the side of the reference roll or the roll chocks of the work rolls of the roll system on the side opposite to the reference roll and the reinforcing roll in the rolling direction, wherein the second step of bringing the work rolls into a roll contact state performs the following steps: a second reference value calculation step of rotating the roller in a predetermined rotation direction, detecting the load in the depressing direction on the working side and the load in the depressing direction on the driving side for each of the upper roller system and the lower roller system, and calculating a second reference value based on a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side; a second control target value calculation step of reversing the rotation direction of the roller, detecting the pressing direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a second control target value based on a deviation between a pressing direction load difference, which is a difference between the pressing direction load of the working side and the pressing direction load of the driving side, and a second reference value; and a second adjustment step of adjusting the positions of the roll chocks so that the load difference in the rolling direction becomes a value within an allowable range of a second control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

In a 6-roll rolling mill including intermediate rolls between work rolls and reinforcing rolls, a first step may be performed in which a plurality of rolls disposed on the upper side in the rolling direction with respect to a material to be rolled are set as an upper roll system and a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system, a position between a roll bearing seat of the intermediate roll and a roll bearing seat of the reinforcing roll is adjusted for each of an upper roll system and a lower roll system in a state where a roll gap of the work rolls is opened and a bending force is applied to the roll bearing seat of the intermediate roll by a bending device, a second step may be performed after the first step is completed, a position between the roll bearing seat of the intermediate roll and the roll bearing seat of the work rolls is adjusted for each of the upper roll system and the lower roll system in a state where the roll gap of the work rolls is maintained opened and a bending force is applied to the roll bearing seat of the work rolls by the bending device in the second step, after the second step is completed, a third step is performed in which the work rolls are brought into contact with each other to adjust the positions of the roll chocks of the upper roll system and the lower roll system, and in the first step, the following steps are performed: a first reference value calculation step of rotating the roller in a predetermined rotation direction, detecting the load in the depressing direction on the working side and the load in the depressing direction on the driving side for each of the upper roller system and the lower roller system, and calculating a first reference value based on a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side; a first control target value calculation step of reversing the rotation direction of the roller, detecting the pressing direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a first control target value based on a deviation between a pressing direction load difference, which is a difference between the pressing direction load of the working side and the pressing direction load of the driving side, and a first reference value; and a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving either one of the roll chock of the intermediate roll of the roll system on the opposite side of the reference roll and the roll chock of the reinforcing roll, and the roll chock of the intermediate roll of the roll system on the reference roll side in the rolling direction, wherein the second adjustment step is performed by: a second reference value calculation step of rotating the roller in a predetermined rotation direction, detecting the load in the depressing direction on the working side and the load in the depressing direction on the driving side for each of the upper roller system and the lower roller system, and calculating a second reference value based on a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side; a second control target value calculation step of reversing the rotation direction of the roller, detecting the pressing direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a second control target value based on a deviation between a pressing direction load difference, which is a difference between the pressing direction load of the working side and the pressing direction load of the driving side, and a second reference value; and a second adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference is within an allowable range of a second control target value by moving the roll chocks of the work roll of the roll system on the opposite side of the reference roll, one of the roll chocks of the intermediate roll and the reinforcing roll, and the roll chock of the work roll of the roll system on the reference roll side in the rolling direction, wherein in the third step, the work roll is brought into a roll contact state, and in the third step, the following steps are performed: a third reference value calculation step of rotating the roller in a predetermined rotation direction, detecting the load in the depressing direction on the working side and the load in the depressing direction on the driving side for each of the upper roller system and the lower roller system, and calculating a third reference value based on a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side; a third control target value calculation step of reversing the rotation direction of the roller, detecting the pressing-down direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a third control target value based on a deviation between a pressing-down direction load difference, which is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side, and a third reference value; and a third adjustment step of adjusting the position of the roll chocks by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system so that the rolling direction load difference is within an allowable range of a third control target value.

Alternatively, in a 4-roll rolling mill, a plurality of rolls disposed on the upper side in the rolling direction with respect to a material to be rolled may be set as an upper roll system, and a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled may be set as a lower roll system, and a first step may be performed in which, in a state in which a roll gap of a work roll is opened and a bending force is applied to a roll bearing seat of the work roll by a bending device, positions between the roll bearing seat of the work roll and a roll bearing seat of a reinforcing roll are adjusted for each of the upper roll system and the lower roll system, and after the first step is completed, a second step may be performed in which the work roll is brought into contact with each other to adjust the positions of the roll bearing seats of the upper roll system and the lower roll system, and the first step may perform the following steps: a first control target value calculation step of detecting the pressing-down direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a first reference value based on a pressing-down direction load difference, which is a difference between the pressing-down direction load of the working side and the pressing-down direction load of the driving side, and setting a first control target value based on the first reference value; a first load difference step of rotating the rollers, detecting the load in the depressing directions of the working side and the driving side for the upper roller system and the lower roller system, respectively, and calculating a load difference in the depressing directions, which is a difference between the load in the depressing directions of the working side and the drive side; and a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving the roll chocks of the work roll of the roll system on the side of the reference roll or the roll chocks of the work roll of the roll system on the side opposite to the reference roll or the reinforcing roll in the rolling direction, wherein the second step of bringing the work roll into a roll contact state performs the following steps: a second control target value calculation step of detecting the pressing-down direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a second reference value based on a pressing-down direction load difference, which is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side, and setting a second control target value based on the second reference value; a second load difference calculation step of rotating the rollers, detecting the load in the pressing direction on the working side and the load in the pressing direction on the driving side for the upper roller system and the lower roller system, respectively, and calculating a load difference in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side; and a second adjustment step of adjusting the positions of the roll chocks so that the load difference in the rolling direction becomes a value within an allowable range of a second control target value by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system.

In a 6-roll rolling mill including intermediate rolls between work rolls and reinforcing rolls, a first step may be performed in which a plurality of rolls disposed on the upper side in the rolling direction with respect to a material to be rolled are set as an upper roll system and a plurality of rolls disposed on the lower side in the rolling direction with respect to the material to be rolled are set as a lower roll system, a position between a roll bearing seat of the intermediate roll and a roll bearing seat of the reinforcing roll is adjusted for each of an upper roll system and a lower roll system in a state where a roll gap of the work rolls is opened and a bending force is applied to the roll bearing seat of the intermediate roll by a bending device, a second step may be performed after the first step is completed, a position between the roll bearing seat of the intermediate roll and the roll bearing seat of the work rolls is adjusted for each of the upper roll system and the lower roll system in a state where the roll gap of the work rolls is maintained opened and a bending force is applied to the roll bearing seat of the work rolls by the bending device in the second step, after the second step is completed, a third step is performed in which the work rolls are brought into contact with each other to adjust the positions of the roll chocks of the upper roll system and the lower roll system, and in the first step, the following steps are performed: a first control target value calculation step of detecting the pressing-down direction loads of the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a first reference value based on a pressing-down direction load difference, which is a difference between the pressing-down direction load of the working side and the pressing-down direction load of the driving side, and setting a first control target value based on the first reference value; a first load difference calculation step of rotating the rollers, detecting the load in the pressing direction on the working side and the load in the pressing direction on the driving side for the upper roller system and the lower roller system, respectively, and calculating a load difference in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side; and a first adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference becomes a value within an allowable range of the first control target value by moving one of the roll chock of the intermediate roll of the roll system on the opposite side of the reference roll and the reinforcing roll and the roll chock of the intermediate roll of the roll system on the reference roll side in the rolling direction, wherein the second adjustment step implements: a second control target value calculation step of detecting the pressing-down direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where the rotation of the roller is stopped, calculating a second reference value based on a difference in the pressing-down direction loads between the pressing-down direction load on the working side and the pressing-down direction load on the driving side, and setting a second control target value based on the second reference value; a second load difference calculation step of rotating the rollers, detecting the load in the pressing direction on the working side and the load in the pressing direction on the driving side for the upper roller system and the lower roller system, respectively, and calculating a load difference in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side; and a second adjustment step of adjusting the position of the roll chocks so that the rolling direction load difference is within an allowable range of a second control target value by moving the roll chocks of the work roll of the roll system on the opposite side of the reference roll, one of the roll chocks of the intermediate roll and the reinforcing roll, and the roll chock of the work roll of the roll system on the reference roll side in the rolling direction, wherein the third step is to bring the work rolls into a roll contact state, and wherein the third step is to perform: a third control target value calculation step of detecting the pressing-down direction loads on the working side and the driving side for the upper roller system and the lower roller system, respectively, in a state where rotation of the roller is stopped, calculating a third reference value from a pressing-down direction load difference, which is a difference between the pressing-down direction load on the working side and the pressing-down direction load on the driving side, based on the third reference value, and setting a third control target value; a third load difference calculation step of rotating the rollers, detecting the load in the pressing direction on the working side and the load in the pressing direction on the driving side for the upper roller system and the lower roller system, respectively, and calculating a load difference in the pressing direction, which is a difference between the load in the pressing direction on the working side and the load in the pressing direction on the driving side; and a third adjustment step of adjusting the position of the roll chocks by controlling the roll chocks of the rolls of the other roll system simultaneously and in the same direction while maintaining the relative positions of the roll chocks of the rolls of the other roll system with one of the upper roll system and the lower roll system as a reference roll system so that the rolling direction load difference is within an allowable range of a third control target value.

ADVANTAGEOUS EFFECTS OF INVENTION

As described above, according to the present invention, the thrust force generated between the rolls can be reduced before the rolling position zero point is adjusted or before the rolling is started, and the occurrence of meandering and warping of the rolled material can be suppressed.

Drawings

Fig. 1 is a schematic side view and a schematic front view of a rolling mill for explaining thrust and thrust reaction force generated between rolls of the rolling mill during rolling.

Fig. 2 is an explanatory diagram showing the configuration of a rolling mill and a device for controlling the rolling mill according to a first embodiment of the present invention.

Fig. 3A is a flowchart for explaining a method of setting a rolling mill for adjusting the position of a roller bearing seat based on the load in the pressing direction at the time of normal rotation and reverse rotation of the roller according to this embodiment, and explains the first adjustment in the roll gap open state.

Fig. 3B is a flowchart for explaining a setting method of a rolling mill for adjusting the position of a roller bearing seat based on the load in the pressing direction at the time of normal rotation and reverse rotation of the roller according to the embodiment, and explains a second adjustment in a state where the roller is in contact with the roller.

Fig. 4A is an explanatory diagram illustrating a procedure of position adjustment of the roller bearing seat in the setting method of the rolling mill according to the embodiment, and illustrates the position adjustment in the nip open state.

Fig. 4B is an explanatory diagram illustrating a procedure of adjusting the position of the roller bearing seat in the setting method of the rolling mill according to the embodiment, and illustrates the position adjustment in the roller contact state.

Fig. 5 is a schematic side view and a schematic front view showing an example of a driving state of the rolling mill in the case of identifying the intersection angle between the rolls.

Fig. 6 is an explanatory diagram showing the difference in the load in the rolling direction obtained when the lower roll is rotated in the normal direction and in the reverse direction in the rolling mill in the state of fig. 5.

Fig. 7A is a flowchart for explaining a setting method of a rolling mill for adjusting the position of a roller bearing seat based on the load in the rolling direction when the roller is stopped and when the roller is rotated according to the second embodiment of the present invention, and a first adjustment in the roll gap open state will be described.

Fig. 7B is a flowchart for explaining a setting method of a rolling mill for adjusting the position of a roller bearing seat based on the load in the rolling direction when the roller is stopped and when the roller is rotated according to the embodiment, and a second adjustment in a state where the roller is in contact with the roller will be explained.

Fig. 8A is an explanatory diagram illustrating a procedure of position adjustment of the roller bearing seat in the setting method of the rolling mill according to the embodiment, and illustrates the position adjustment in the nip open state.

Fig. 8B is an explanatory diagram illustrating a procedure of adjusting the position of the roller bearing seat in the setting method of the rolling mill according to the embodiment, and illustrates the position adjustment in the roller contact state.

Fig. 9 is a schematic side view and a schematic front view showing another example of the driving state of the rolling mill in the state of identifying the intersection angle between the rolls.

Fig. 10 is an explanatory diagram showing a difference in the rolling direction load obtained when the lower roll is stopped and rotated in the rolling mill in the state of fig. 9.

Fig. 11 is an explanatory diagram showing the arrangement of the work rolls and the stiffening rolls of the rolling mill with the nip in the open state.

Fig. 12 is an explanatory diagram showing the definition of the intersection angle between the rollers.

FIG. 13 is a graph showing a relationship between a crossing angle of the reinforcing rollers and a load difference in a depressing direction in the nip-opened state shown in FIG. 11.

Fig. 14 is an explanatory diagram showing the arrangement of the work rolls and the stiffening rolls of the rolling mill set in the roll contact state, and shows a state in which the work rolls and the stiffening rolls intersect in pairs.

Fig. 15 is a graph showing a relationship between a reinforcing roller intersection angle and a load difference in the depressing direction in the roller contact state shown in fig. 14.

Fig. 16 is an explanatory diagram showing an example in which a servo motor with a rotation angle detection function is applied instead of the hydraulic cylinder provided with the roller bearing seat position detection device.

Fig. 17A is an explanatory diagram showing a procedure of adjustment of the roll chock position (first adjustment) in the case where the setting method of the rolling mill shown in fig. 4A or 8A is applied to a 6-high rolling mill.

Fig. 17B is an explanatory diagram showing a procedure of adjustment of the roll chock position (second adjustment) in the case where the setting method according to the present embodiment is applied to a 6-high rolling mill.

Fig. 17C is an explanatory diagram showing a procedure of the adjustment of the roll chock position (third adjustment) in the case where the setting method of the rolling mill shown in fig. 4B or 8B is applied to a 6-high rolling mill.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the present specification and the drawings, the same reference numerals are given to components having substantially the same functional configuration, and redundant description is omitted.

<1. purpose >

In the rolling mill and the setting method of the rolling mill according to the embodiment of the present invention, it is an object to eliminate a thrust force generated between rolls and to stably manufacture a product free from meandering and warping or a product having extremely slight meandering and warping. Fig. 1 shows a schematic side view and a schematic front view of a rolling mill for explaining thrust and thrust reaction force generated between rolls of the rolling mill when rolling a material S to be rolled. Hereinafter, as shown in fig. 1, the working side in the longitudinal direction of the roll body is denoted by ws (work side), and the driving side is denoted by ds (drive side).

The rolling mill shown in fig. 1 has: a pair of work rolls consisting of an upper work roll 1 and a lower work roll 2; and a pair of reinforcing rollers consisting of an upper reinforcing roller 3 supporting the upper work roller 1 in the depressing direction (Z direction) and a lower reinforcing roller 4 supporting the lower work roller 2. The material S to be rolled is rolled by passing the material S between the work rolls, so that the thickness of the material S to be rolled is a predetermined thickness. The rolling mill is provided with upper rolling direction load detecting devices 28a and 28b for detecting a rolling direction load in relation to an upper roll system including an upper work roll 1 and an upper reinforcing roll 3 arranged on the upper surface side of a material S to be rolled, and lower rolling direction load detecting devices 29a and 29b for detecting a rolling direction load in relation to a lower roll system including a lower work roll 2 and a lower reinforcing roll 4 arranged on the lower surface side of the material S to be rolled in a rolling direction (Z direction), and lower rolling direction load detecting devices 28a and 28b for detecting a rolling direction load in relation to the upper roll system in the rolling direction (Z direction). The up-pressing-direction load detecting device 28a and the pressing-direction load detecting device 29a detect a pressing-direction load on the working side. The up-pressing-direction load detecting device 28b and the pressing-direction load detecting device 29b detect the pressing-direction load on the driving side.

The upper work rolls 1, the lower work rolls 2, the upper reinforcing rolls 3, and the lower reinforcing rolls 4 are arranged so that the body length directions of the rolls are parallel to each other so as to be orthogonal to the conveying direction of the rolled material S. However, when the rolls are slightly rotated about an axis (Z axis) parallel to the roll-down direction and the upper work roll 1 and the upper reinforcing roll 3 are displaced in the body length direction or the lower work roll 2 and the lower reinforcing roll 4 are displaced in the body length direction, a thrust force acting in the body length direction of the rolls is generated between the work rolls and the reinforcing rolls. The roll thrust causes moment to be generated in the rolls to cause asymmetric roll deformation, which is one cause of unstable rolling, for example, meandering or warping. The work roll and the reinforcing roll are displaced in the longitudinal direction of the roll body to generate an intersection angle between the rolls, thereby generating the thrust between the rolls. For example, when a roll intersection angle is generated between the lower work roll 2 and the lower reinforcing roll 4, a thrust force is generated between the lower work roll 2 and the lower reinforcing roll 4, and as a result, a moment is generated in the lower reinforcing roll 4, and a load distribution between the rolls is changed so as to be balanced with the moment, resulting in asymmetric roll deformation. The asymmetric roll deformation causes meandering, warping, and the like, and the rolling becomes unstable.

Therefore, an object of the present invention is to stably produce a product free from meandering and warping or a product having extremely slight meandering and warping by adjusting the position of the roller bearing seat of each roller to eliminate the thrust force between the rollers generated during rolling of a material to be rolled by a rolling mill. In particular, the present invention proposes a method of adjusting the position of the roller bearing seat of each roller to cancel the thrust between the rollers generated even when the thrust reaction force applied to the rollers cannot be measured.

<2 > first embodiment

The rolling mill according to the first embodiment of the present invention, the configuration of the apparatus for controlling the rolling mill, and the setting method of the rolling mill will be described with reference to fig. 2 to 4B. In the first embodiment, before the zero point adjustment of the rolling position or before the start of rolling, the roll angle between the reinforcing roll and the other roll as a reference is adjusted to zero, thereby realizing rolling without generating thrust. The rolling mill according to the present embodiment can also adjust the intersection between the rolls even when the rolling mill is not provided with a thrust reaction force measuring device for measuring a thrust reaction force and cannot measure a thrust reaction force applied to the rolls.

[2-1. Structure of Rolling Mill ]

First, a rolling mill and a device for controlling the rolling mill according to the present embodiment will be described with reference to fig. 2. Fig. 2 is an explanatory diagram showing the configuration of the rolling mill according to the present embodiment and a device for controlling the rolling mill. The rolling mill shown in fig. 2 is in a state of being viewed from the working side in the roll longitudinal direction, and the rolling direction is from the left side to the right side of the drawing sheet. Fig. 2 shows a configuration in which the lower reinforcing roller is used as a reference roller. In the invention according to the present embodiment, any one of the rollers arranged in the pressing direction may be used as the reference roller. The reference roller is preferably a roller having a large contact area between the bearing housing and the casing and positioned at the lowermost portion or the uppermost portion in a stable position.

The rolling mill shown in fig. 2 is a 4-roll rolling mill having a pair of work rolls 1 and 2 and a pair of reinforcing rolls 3 and 4 supporting the pair of work rolls 1 and 2. In the 4-roll mill, the upper work roll 1, the lower work roll 2, the upper reinforcing roll 3, and the lower reinforcing roll 4 are a plurality of rolls arranged in the rolling direction. The upper work roll 1 is supported by an upper work roll chock 5 and the lower work roll 2 is supported by a lower work roll chock 6. Similarly, an upper work roll chock 5 and a lower work roll chock 6 are provided on the back side (drive side) of the sheet of fig. 2, and the upper work roll chock 5 and the lower work roll chock 6 support the upper work roll 1 and the lower work roll 2, respectively. The upper work roll 1 and the lower work roll 2 are rotationally driven by a drive motor 21. The upper reinforcing roll 3 is supported by an upper reinforcing roll chock 7, and the lower reinforcing roll 4 is supported by a lower reinforcing roll chock 8. Similarly, an upper reinforcing roller bearing housing 7 and a lower reinforcing roller bearing housing 8 are provided on the back side (drive side) of the sheet of fig. 2, and the upper reinforcing roller bearing housing 7 and the lower reinforcing roller bearing housing 8 support the upper reinforcing roller 3 and the lower reinforcing roller 4, respectively. The upper work roll chock 5, the lower work roll chock 6, the upper reinforcing roll chock 7 and the lower reinforcing roll chock 8 are held by a housing 30. The upper work roll chock 5, the lower work roll chock 6, the upper reinforcing roll chock 7, and the lower reinforcing roll chock 8 may be simply referred to as roll chocks.

The upper work roll chock 5 is provided with an upper work roll chock pressing device 9 and a driving device 11 having a belt work roll chock position detecting function, the upper work roll chock pressing device 9 is provided on the entry side in the rolling direction to press the upper work roll chock 5 in the rolling direction, and the driving device 11 having a belt work roll chock position detecting function is provided on the exit side in the rolling direction to detect the position in the rolling direction and drive the upper work roll chock 5 in the rolling direction.

Similarly, the lower work roll chock 6 is provided with a lower work roll chock pressing device 10 and a drive device 12 having a lower work roll chock position detecting function, the lower work roll chock pressing device 10 is provided on the entry side in the rolling direction to press the lower work roll chock 6 in the rolling direction, and the drive device 12 having a lower work roll chock position detecting function is provided on the exit side in the rolling direction to detect the position in the rolling direction and drive the lower work roll chock 6 in the rolling direction. For example, hydraulic cylinders are used for the drive device 11 for detecting the position of the bearing seat of the on-belt work roll, the drive device 12 for detecting the position of the bearing seat of the off-belt work roll, the drive mechanism for the upper work roll bearing housing pressing device 9, and the drive mechanism for the lower work roll bearing housing pressing device 10. In fig. 2, only the driving device 11 with work roll bearing seat position detecting function, the driving device 12 with work roll bearing seat position detecting function, the upper work roll bearing seat pressing device 9, and the lower work roll bearing seat pressing device 10 on the work side are shown, but these devices are similarly provided on the back side (drive side) of the sheet.

The upper reinforcing roller bearing housing 7 is provided with an upper reinforcing roller bearing housing pressing device 13 and a driving device 14 having a function of detecting the position of the upper reinforcing roller bearing housing, the upper reinforcing roller bearing housing pressing device 13 is provided on the exit side in the rolling direction to press the upper reinforcing roller bearing housing 7 in the rolling direction, and the driving device 14 having a function of detecting the position of the upper reinforcing roller bearing housing is provided on the entry side in the rolling direction to detect the position in the rolling direction and drive the upper reinforcing roller bearing housing 7 in the rolling direction. For example, hydraulic cylinders are used for the drive mechanisms of the drive device 14 having the function of detecting the position of the belt reinforcing roller bearing holder and the upper reinforcing roller bearing holder pressing device 13. In fig. 2, only the drive device 14 for detecting the position of the working-side belt reinforcing roller bearing seat and the upper reinforcing roller bearing seat pressing device 13 are shown, but these devices are similarly provided on the back side (drive side) of the sheet.

On the other hand, in the present embodiment, the lower reinforcing roller 4 is used as the reference roller, and therefore the lower reinforcing roller bearing housing 8 serves as the reference reinforcing roller bearing housing. Therefore, the lower reinforcing-roller bearing housing 8 is not driven to adjust the position, and therefore, a driving device and a position detecting device are not necessarily provided as in the upper reinforcing-roller bearing housing 7. However, for example, the lower reinforcing roll chock pressing device 40 may be provided on the entry side or the exit side in the rolling direction so as to suppress the wobbling of the lower reinforcing roll chock 8 and prevent the position of the reference reinforcing roll chock as a reference for the position adjustment from being changed. In fig. 2, only the lower reinforcing roller bearing holder pressing device 40 on the working side is shown, but the lower reinforcing roller bearing holder pressing device 40 is similarly provided on the back side (driving side) of the drawing sheet.

The upper working roll chock pressing device 9, the lower working roll chock pressing device 10, the upper reinforcing roll chock pressing device 13, and the lower reinforcing roll chock pressing device 40 are provided on either the entry side or the exit side of the material to be rolled in the rolling direction, and are pressing devices that press the roll chocks in the rolling direction, and may be simply referred to as pressing devices. The pressing device may be provided at least for the roller bearing holder of the roller other than the reference roller. The drive device 11 for detecting the position of the roll bearing seat for the in-band work, the drive device 12 for detecting the position of the roll bearing seat for the in-band work, and the drive device 14 for detecting the position of the roll bearing seat for the in-band reinforcement are provided so as to face the pressing devices in the rolling direction, and are drive devices for moving the roll chocks in the rolling direction, and may be simply referred to as drive devices. The driving device may be provided at least for the roller bearing holder of the roller other than the reference roller.

The rolling mill according to the present embodiment includes a counterweight (project block) between the upper work roll chock 5 and the housing 30, and an entrance-side bending enlargement device 24a and an exit-side bending enlargement device 24 b. The rolling mill further includes an entry-side lower enlarging curving device 25a and an exit-side lower enlarging curving device 25b in the counterweight between the lower work roll chock 6 and the housing 30. Similarly, an inlet side upper enlarging and bending device 24a, an outlet side upper enlarging and bending device 24b, an inlet side lower enlarging and bending device 25a, and an outlet side lower enlarging and bending device 25b are provided on the back side (driving side) of the sheet of fig. 2. Each of the bending enlarging apparatuses applies a bending enlarging force to the work roll bearing blocks, and the bending enlarging force applies a load to the upper work roll 1 and the upper reinforcing roll 3, and the lower work roll 2 and the lower reinforcing roll 4. The entrance-side upper enlarging and bending device 24a, the exit-side upper enlarging and bending device 24b, the entrance-side lower enlarging and bending device 25a, and the exit-side lower enlarging and bending device 25b are bending devices that apply bending forces to the rollers, and may be simply referred to as bending devices.

As shown in fig. 2, the rolling mill includes a roll bearing rolling direction force control device 15, a roll bearing seat position control device 16, a drive motor control device 22, an inter-roll intersection control device 23, and an increase bending control device 26.

The roll chock rolling direction force control device 15 controls the rolling direction pressing forces of the upper working roll chock pressing device 9, the lower working roll chock pressing device 10, the upper reinforcing roll chock pressing device 13, and the lower reinforcing roll chock pressing device 40. The roll chock rolling direction force control device 15 drives the upper working roll chock pressing device 9, the lower working roll chock pressing device 10, and the upper reinforcing roll chock pressing device 13, which are control targets of the chock positions, based on a control instruction of an inter-roll intersection control device 23, which will be described later, and provides a predetermined pressing force to control the chock positions.

The roller bearing seat position control device 16 controls the drive device 11 having the function of detecting the position of the working roller bearing seat on the belt, the drive device 12 having the function of detecting the position of the working roller bearing seat on the belt, and the drive device 14 having the function of detecting the position of the reinforcing roller bearing seat on the belt. The roller bearing seat position control device 16 is also simply referred to as a position control device. The roller bearing seat position control device 16 drives the driving device 11 for the belt-in-process roller bearing seat position detection function, the driving device 12 for the belt-out-process roller bearing seat position detection function, and the driving device 14 for the belt-in-process reinforcing roller bearing seat position detection function based on the control instruction of the inter-roller intersection control device 23 so that the difference between the rolling direction load on the process side and the rolling direction load on the drive side of the roller, that is, the rolling direction load difference is within a predetermined range. The driving devices 11, 12, and 14 with position detection function are disposed on both the working side and the driving side, and by controlling the positions in the rolling direction of the working side and the driving side in opposite directions by the same amount on the working side and the driving side, only the roll intersection angle can be changed without changing the average rolling direction position of the working side and the driving side.

The drive motor control device 22 controls the drive motor 21 for rotationally driving the upper work roll 1 and the lower work roll 2. The driving motor control device 22 according to the present embodiment controls the driving of the upper work roll 1 or the lower work roll 2 based on an instruction from the inter-roll intersection control device 23.

The inter-roll intersection control device 23 controls the positions of the upper work roll 1, the lower work roll 2, the upper reinforce roll 3, and the lower reinforce roll 4 constituting the rolling mill so that the inter-roll intersection angle becomes zero. The inter-roll intersection control device 23 gives control instructions to the roll chock rolling direction force control device 15, the roll chock seat position control device 16, and the drive motor control device 22 so that the difference between the rolling direction load on the work side and the rolling direction load on the drive side of the rolls, that is, the difference between the rolling direction loads, falls within a predetermined range, thereby eliminating the intersection generated between the rolls. The details of the setting method of the rolling mill will be described later.

The enlargement bending control device 26 controls the entrance-side upper enlargement bending device 24a, the exit-side upper enlargement bending device 24b, the entrance-side lower enlargement bending device 25a, and the exit-side lower enlargement bending device 25 b. The incremental bending control device 26 controls the incremental bending device to provide an incremental bending force to the work roll bearing blocks based on an instruction from the inter-roll intersection control device 23. The bending enlargement control device 26 may also control the bending enlargement device when, for example, crown (crown) control or shape control is performed on the material to be rolled, in a case other than the case of performing the adjustment of the intersection between the rolls according to the present embodiment.

In addition, a screw-down device 27 is provided in the rolling mill. The press-down device 27 is a device which is provided above the uppermost roller (the upper reinforcing roller 3 in fig. 2) and presses the roller downward. The rollers are pressed downward from above by the pressing device 27, and the positions of the rollers in the pressing direction can be adjusted. For example, when the upper work roll 1 and the lower work roll 2 are brought into contact with each other, a predetermined load is applied to the upper work roll 1 and the lower work roll 2 by the press-down device 27, and the positions thereof are adjusted.

Upper depressing direction load detection means 28a and 28b and a depressing means 27 are provided at a depressing fulcrum position 30a between the upper reinforcing roller bearing support 7 and the housing 30 in the depressing direction, and lower depressing direction load detection means 29a and 29b are provided at a depressing fulcrum position 30b between the lower reinforcing roller bearing support 8 and the housing 30. In fig. 2, only the up-pressing direction load detecting device 28a and the down-pressing direction load detecting device 29a on the working side are shown, but as shown in fig. 1, an up-pressing direction load detecting device 28b and a down-pressing direction load detecting device 29b are provided on the driving side on the back side of the sheet of fig. 2. The up-pressing direction load detection devices 28a and 28b and the down-pressing direction load detection devices 29a and 29b are devices that are disposed at the pressing fulcrum positions of the upper and lower reinforcing roller bearing blocks and detect a pressing direction load acting in the pressing direction, the up-pressing direction load detection devices 28a and 28b detect the pressing direction load with respect to the uppermost roller, and the down-pressing direction load detection devices 29a and 29b detect the pressing direction load with respect to the lowermost roller.

The up-depressing-direction load difference calculation unit 32 calculates a depressing-direction load difference, which is a difference between the depressing-direction load on the working side and the depressing-direction load on the driving side detected by the up-depressing-direction load detection devices 28a and 28 b. The depressing direction load difference calculation unit 33 calculates a depressing direction load difference, which is a difference between the depressing direction load on the working side and the depressing direction load on the driving side detected by the depressing direction load detection devices 29a and 29 b. The load difference in the pressing direction calculated by the load difference in the pressing direction calculating unit 32 and the load difference in the pressing direction calculating unit 33 is output to the inter-roller intersection control device 23. The inter-roller-crossing control device 23 recognizes the state of the inter-roller crossing based on the load difference in the pressing direction being input.

In the above examples, the following examples are described but the present invention is not limited to the examples: the work roll chocks 5 and 6 are provided with drive devices 11 and 12 having a strip position detecting function on the exit side of the rolling mill, pressing devices 9 and 10 on the entry side, the upper stiffening roll chock 7 is provided with a drive device 14 having a strip position detecting function on the entry side of the rolling mill, the exit side is provided with a pressing device 13, and the lower stiffening roll chock 8 is provided with a pressing device 40 on the exit side of the rolling mill. For example, these arrangements may be reversed on the entry side and exit side of the rolling mill, or may be arranged in the same direction in the work rolls and the reinforcing rolls. Further, although the examples have been described in which the driving devices 11, 12, and 14 with position detection functions are disposed on both the working side and the driving side and position control is performed on each side, the present invention is not limited to the above examples. These devices can be arranged only on one of the work side and the drive side, or can be operated only on one side, and the position of the devices can be controlled using the opposite side of the one side as a fulcrum of rotation, whereby the roll intersection angle can be controlled, and the same effect of reducing the intersection between the rolls can be obtained. In fig. 2, although an example in which only the pressing device 40 is provided to the lower reinforcing roller bearing housing 8 of the lower reinforcing roller 4 as the reference roller is shown, the present invention is not limited to the above example, and a driving device having a belt position detection function may be provided on the entry side of the lower reinforcing roller bearing housing 8, and may be controlled by the roller bearing housing position control device 16. Thus, for example, when the orthogonal relationship between the reference roll shaft and the rolling direction is extremely deviated due to wear of the spacer or the like, the reference reinforcing roll chock can be driven by the roll chock position control device 16 to finely adjust the position of the reference roll. Further, the reference roller may be changed according to the situation by arranging a driving device having a belt position detecting function for all the rollers, and the control may be performed based on the changed reference roller.

[2-2. setting method of Rolling Mill ]

Next, a method of setting a rolling mill according to the present embodiment will be described with reference to fig. 3A to 6. Fig. 3A and 3B are flowcharts illustrating a method of setting a rolling mill in which the position of a roller bearing seat is adjusted based on the load in the rolling direction at the time of normal rotation and reverse rotation of the roller according to the present embodiment. Fig. 4A is an explanatory diagram illustrating a procedure of position adjustment of the roller bearing seat in the setting method of the rolling mill according to the present embodiment, and illustrates the position adjustment in the nip open state. Fig. 4B is an explanatory diagram illustrating a procedure of adjusting the position of the roller bearing seat in the setting method of the rolling mill according to the present embodiment, and illustrates the position adjustment in the roller contact state. In fig. 4A and 4B, the distribution of the load acting between the rollers is not shown. Fig. 5 is a schematic side view and a schematic front view showing an example of a driving state of the rolling mill in the case of identifying the intersection angle between the rolls. In fig. 5, the load distribution changes with a change in the direction of the thrust between the lower work roll 2 and the lower reinforcing roll 4 when the rolls are rotating in the forward and reverse directions, but the difference is not noted here because it is slightly changed. Fig. 6 is an explanatory diagram showing the difference in the load in the rolling direction obtained when the lower roll is rotated in the normal direction and in the reverse direction in the rolling mill in the state of fig. 5. In this example, the lower reinforcing roller 4 is described as the reference roller, but the reference roller may be either the uppermost roller or the lowermost roller in the depressing direction, and the upper reinforcing roller 3 may be the reference roller.

In the setting method of the rolling mill according to the present embodiment, when the nip between the upper work roll 1 and the lower work roll 2 is opened and when the rolls are in contact with each other, the load difference in the rolling direction is calculated from the driving-side and working-side load in the rolling direction detected by the load detection devices 28a and 28b in the rolling direction, and the load difference in the rolling direction is calculated from the driving-side and working-side load in the rolling direction detected by the load detection devices 29a and 29b in the rolling direction. Then, the position of the roll chocks is adjusted based on the calculated load difference in the rolling direction so that the roll-to-roll intersection of the rolls of the rolling mill falls within a predetermined range. At this time, the rolling direction position of the roll chocks of the reference rolls is fixed as a reference position, and the positions of the roll chocks of the rolls other than the reference rolls are adjusted by moving the positions in the rolling direction. The following describes the details.

(A) First adjustment: position adjustment in the roll gap open state (S100-S116)

In the first adjustment for adjusting the position in the nip open state, the upper work roll and the lower work roll are opened and an increased bending force is applied to provide a load between the work roll and the reinforcing roll, and in this state, the upper and lower work roll chock positions are controlled so that the difference in the load in the pressing direction due to the thrust between the rolls becomes a predetermined target value. First, as shown in fig. 3A, the inter-roll intersection control device 23 causes the press-down device 27 to adjust the roll position in the press-down direction so that the nip between the upper work roll 1 and the lower work roll 2 is opened with a predetermined gap (S100). The press device 27 applies a predetermined load to the rollers based on the instruction, and opens the nip between the work rollers 1 and 2.

The inter-roller-crossing control device 23 instructs the bending-increase control device 26 to apply a predetermined bending-increase force to the work-roller chocks 5 and 6 by the bending-increase devices 24a, 24b, 25a, and 25b (S102). The bend-increasing controller 26 controls the bend-increasing devices 24a, 24b, 25a, and 25b based on the instruction to apply a predetermined bend-increasing force to the work roll chocks 5 and 6. This makes it possible to provide a predetermined load only between the upper and lower work rolls and the reinforcing roll without causing a load action between the upper and lower work rolls. In the case where the bending apparatus has a function of a balancer for lifting the weight of the work rolls, the order of step S100 and step S102 may be reversed, that is, the gap between the upper and lower work rolls may be adjusted after the bending force is increased.

Next, the inter-roller intersection control device 23 instructs the drive motor control device 22 to drive the drive motor 21, and rotates the work roller at a predetermined rotational speed and in a predetermined rotational direction (S104). The rotation speed and the rotation direction as the roller rotation conditions are set in advance, and the driving motor control device 22 rotates the upper work roller 1 and the lower work roller 2 under the set roller rotation conditions. The rotation direction of each work roll 1, 2 in step S104 is set to the normal rotation direction. When the work roll rotates, the pressing-down direction loads on the work side and the drive side are detected by the upper pressing-down direction load detecting devices 28a and 28b and the lower pressing-down direction load detecting devices 29a and 29b, respectively, and output to the upper pressing-down direction load difference calculating unit 32 and the lower pressing-down direction load difference calculating unit 33. The up-depressing-direction load difference calculating section 32 and the depressing-direction load difference calculating section 33 calculate a depressing-direction load difference, which is a difference between a depressing-direction load on the working side and a depressing-direction load on the driving side, when receiving an input of the depressing-direction load. The calculated load difference in the pressing direction at the time of normal rotation of the roller is input to the inter-roller intersection control device 23 and set to a reference value 1 (corresponding to the "first reference value" of the present invention) (S106).

When the reference value 1 is calculated, the rotation direction of the work roll is then reversed, and the process at the time of roll reversal is started. The inter-roller intersection control device 23 drives the driving motor 21 by the driving motor control device 22 to rotate the work roller at a predetermined rotational speed and in a predetermined rotational direction (S108). When the work roll rotates, similarly to the case of normal rotation of the roll, the pressing-down direction load detection means 28a and 28b and the pressing-down direction load detection means 29a and 29b detect the pressing-down direction loads on the work side and the drive side, respectively, and output the detected loads to the pressing-down direction load difference calculation unit 32 and the pressing-down direction load difference calculation unit 33. The rotation direction of each of the work rolls 1 and 2 in step S108 is set to the reverse direction.

The up-pressing-direction load difference calculating unit 32 and the down-pressing-direction load difference calculating unit 33 each calculate a pressing-direction load difference, which is a difference between the pressing-direction load on the working side and the pressing-direction load on the driving side, when receiving the input of the pressing-direction load, and output the calculated differential load at the time of the roller reverse rotation to the inter-roller intersection control device 23. Then, the inter-roller cross control device 23 calculates first control target values for the upper roller system and the lower roller system, respectively, based on the difference between the load difference in the pressing direction when the rollers are reversed and the reference value 1 calculated in step S106 (S110). The first control target value is preferably a value half the deviation from the reference value 1. Further, there is a case where a difference occurs in the characteristic of load difference in the pressing-down direction in the acting direction of the thrust at the time of normal rotation and reverse rotation due to the influence of sliding resistance between the roller bearing holder and the housing, a bearing gap, and the like. In this case, the first control target value may be set based on the previously recognized result, depending on the degree of difference in magnitude between the load difference in the depressing direction at the time of normal rotation and the load difference in the depressing direction at the time of reverse rotation. That is, the first control target value may be a value other than half the deviation from the reference value 1.

After the first control target value is calculated, the depressing direction load on the working side and the depressing direction load on the driving side at the time of the roll reverse rotation are measured for each of the upper roll system and the lower roll system, and the depressing direction load difference is calculated as the difference (S112). Then, the inter-roller cross control device 23 compares the pressing-down direction load difference at the time of the roller reverse rotation calculated in step S112 with the first control target value calculated in step S110, and determines whether or not they match (S114). The determination in step S114 includes not only a case where the difference in load in the pressing direction at the time of the roller reverse rotation completely matches the first control target value, but also a case where the difference in load in the pressing direction at the time of the roller reverse rotation is within the allowable range with respect to the first control target value. The allowable range may be determined, for example, by converting an asymmetric deformation amount obtained from a meandering amount (mm) at the trailing end or a warp performance value (mm/m) per 1m at the leading end and a rolling direction load difference at the time of roll inversion by roll deformation analysis or the like into a rolling leveling amount in an actual hot rolling process, and then obtaining a relationship with a deviation from a first control target value, that is, a relationship with a slight intersection between rolls so that the meandering and the warp become equal to or less than a standard required for a product. When it is determined in step S114 that the load difference in the pressing direction at the time of the roller reverse rotation is not the first control target value or is not within the allowable range, the inter-roller intersection control device 23 instructs the roller chock position control device 16 to adjust the position of the work roller chock of the roller system that does not satisfy the requirement of step S114 (S116). Then, when the position of the work roll chock is adjusted, the processing from step S112 is executed again. In this case, the position of the upper reinforcing roll chock may be controlled instead of the position of the upper work roll chock, so as to reduce the differential load generated by the thrust between the upper work roll and the reinforcing roll.

When it is determined in step S114 that the load difference in the pressing direction at the time of the roller reverse rotation coincides with the first control target value or falls within the allowable range, the inter-roller intersection control device 23 proceeds to the processing shown in fig. 3B.

(calculation of reference value 1 and first control target value)

Here, the calculation of the reference value 1 and the first control target value will be described in detail based on fig. 4A. First, as shown in the upper side of fig. 4A, in the nip open state, the rollers are rotated in the normal direction in the upper roller system composed of the upper work roller 1 and the upper reinforcing roller 3 and the lower roller system composed of the lower work roller 2 and the lower reinforcing roller 4, respectively. At this time, since the upper work roll 1 and the lower work roll 2 are separated, the respective roll systems are in an independent state. In the normal rotation state of the roller, the depressing direction load on the working side and the depressing direction load on the driving side of the upper roller system, and the depressing direction load on the working side and the depressing direction load on the driving side of the lower roller system are measured. Then, the difference between the load in the working direction and the load in the driving direction, that is, the difference in load in the depressing direction, is calculated for each of the upper and lower roller systems based on the measured values (P11, P12 in fig. 4A). The load difference in the rolling direction of each roll system was calculated by the following formula (1).

[ number 1]

Here, P is_df1 ^TIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the upper roll system in the normal rotation state of the rolls (upper reference value 1)^T)，P_df1 ^BIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the lower roll system in the normal rotation state of the rolls (lower reference value 1)^B). The reference value 1 in step S106 is the upper reference value 1^TAnd a lower reference value of 1^B. In addition, P_W ^TIs a measured value of the load in the pressing direction on the working side of the upper roll system in the normal rotation state of the roll, P_W ^BThe measured value is the value of the load on the working side of the lower roll system in the normal rotation state of the roll. And, P_D ^TIs a measured value of the load in the pressing direction on the driving side of the upper roll system in the normal rotation state of the roll, P_D ^BThe measured value is the value of the load in the pressing direction on the driving side of the lower roll system in the normal rotation state of the roll.

Next, the first control target value is calculated based on the measured values of the upper and lower depressing direction loads measured in the roller reverse rotation state on the working side and the driving side, and the reference value 1 calculated by the above equation (1).

Here, when the first control target value is calculated, the relationship between the difference in the load in the depressing direction, which is the difference in the load in the depressing direction between the driving side and the working side in the normal rotation and the reverse rotation, is examined. In the above-described study, for example, as shown in fig. 5, in a rolling mill having a pair of work rolls 1 and 2 and a pair of reinforcing rolls 3 and 4 supporting the pair of work rolls 1 and 2, the upper work roll 1 and the lower work roll 2 are separated from each other, and the nip between the work rolls 1 and 2 is set to an open state. The work side of the upper work roll 1 is supported by an upper work roll chock 5a, and the drive side of the upper work roll 1 is supported by an upper work roll chock 5 b. The working side of the lower work roll 2 is supported by the lower work roll chock 6a, and the driving side of the lower work roll 2 is supported by the lower work roll chock 6 b. The working side of the upper reinforcing roll 3 is supported by an upper reinforcing roll chock 7a, and the driving side of the upper reinforcing roll 3 is supported by an upper reinforcing roll chock 7 b. The working side of the lower reinforcing roll 4 is supported by a lower reinforcing roll chock 8a, and the driving side of the lower reinforcing roll 4 is supported by a lower reinforcing roll chock 8 b. In a state where the work rolls 1 and 2 are separated from each other, an increasing bending force is applied to the upper work roll chocks 5a and 5b and the lower work roll chocks 6a and 6b by an increasing bending device (not shown).

As shown in fig. 5, when the lower work roll 2 and the lower reinforcing roll 4 are rotated in a state where the roll intersection angle is generated between the rolls, thrust is generated between the lower work roll 2 and the lower reinforcing roll 4, and moment is generated in the lower reinforcing roll 4. In this state, in the present verification, the depressing-direction load was detected for the case of rotating the roller forward and the case of rotating the roller backward. For example, as shown in fig. 6, when the rollers are rotated in the normal direction and when the rollers are rotated in the reverse direction, the lower work roller is rotated around an axis (Z axis) parallel to the pressing direction only in a predetermined intersection angle change zone, and the pressing direction load when the intersection angle between the rollers is changed is detected. Fig. 6 is one measurement result obtained by detecting a change in the difference in load in the pressing direction between the normal rotation of the rolls and the reverse rotation of the rolls when the inter-roll intersection angle of the lower work rolls is changed by 0.1 ° toward the exit side of the drive side in a small rolling mill having a work roll diameter of 80 mm. The bending increasing force applied to each work roll bearing block was set to 0.5 tonf/chock.

When the detection result is observed, the difference between the load in the driving direction and the load in the working direction, which is obtained when the rollers rotate in the normal direction, is larger in the negative direction than before the change of the intersection angle between the rollers. On the other hand, the difference between the driving-side load in the depression direction and the working-side load in the depression direction, that is, the difference in load in the depression direction, which is obtained when the rollers are reversed, is larger in the positive direction than before the change in the intersection angle between the rollers. In this way, the magnitude of the load difference in the pressing direction is substantially the same between the normal rotation of the roller and the reverse rotation of the roller, but the direction is opposite.

Therefore, based on the above-described relationship, the roller normal rotation state is set as a reference, and 1/2, which is a deviation from the reference in the roller reverse rotation state, is set as a control target value (first control target value) of a difference in load in the pressing direction in which the thrust between the upper and lower work rollers and the reinforcing roller becomes zero. The first control target value can be represented by the following formula (2).

[ number 2]

Herein, P'_dfT1 ^TIs a first control target value, P'_dfT1 ^BIs a first control target value of the lower roll system. Additionally, P'_W ^TIs a measured value of the load in the direction under the working side pressure of the upper roll system in the state of reverse rotation of the roll, P'_W ^BThe measured value of the load on the working side in the pressing direction of the lower roll system in the reverse rotation state of the rolls. And, P'_D ^TIs a measured value P 'of the load in the pressing direction on the drive side of the upper roll system in the reverse rotation state of the roll'_D ^BIs a measured value P 'of the load in the pressing direction on the drive side of the lower roll system in the reverse rotation state of the roll'_df ^TIs the difference between the measured values of the load in the rolling direction between the working side and the driving side of the upper roll system in the reverse rotation state of the rolls, P'_df ^BThe difference between the measured values of the load in the pressing direction on the working side and the driving side of the lower roll system in the reverse rotation state of the rolls. By which the upper roll system can be calculatedA first control target value of the lower roll system.

Here, although equation (2) is defined so that the magnitude of the load difference in the pressing direction is substantially the same between the normal rotation of the roller and the reverse rotation of the roller, there may be a difference in the characteristic of the load difference in the pressing direction in the acting direction of the thrust between the normal rotation and the reverse rotation due to the influence of the sliding resistance between the roller bearing holder and the housing, the bearing gap, or the like. In this case, the first control target value may be set based on the previously recognized result, depending on the degree of difference in magnitude between the load difference in the depressing direction at the time of normal rotation and the load difference in the depressing direction at the time of reverse rotation. That is, the first control target value may be a value other than half the deviation from the reference value 1.

The driving of the roller bearing seat position at the time of the roller reverse rotation is directed to the roller bearing seats of the rollers other than the reference roller. That is, the position of the upper work roll chock (P13) can be controlled as shown in the center of fig. 4A, and the position of the upper reinforcing roll chock (P15) can be controlled as shown in the lower side of fig. 4A for the upper roll system. On the other hand, in the lower roll system, the lower reinforcing roll 4 is stationary because it is a reference roll, and the position of the lower work roll chock is controlled as shown in the center and the lower side of fig. 4A (P14, P16).

(B) And (3) second adjustment: position adjustment in the roller contact state (S118-S134)

Returning to the description of the flowchart, when the position adjustment in the nip-open state shown in fig. 3A is completed, next, as shown in fig. 3B, the inter-roller cross control device 23 causes the press-down device 27 to adjust the roller position in the pressing-down direction so that the nip between the upper work roller 1 and the lower work roller 2 is in a predetermined roller contact state (S118). The press-down device 27 applies a predetermined load to the rollers based on the instruction, and brings the work rollers 1 and 2 into contact with each other, thereby bringing the rollers into a roller-contact state.

Next, the inter-roller intersection control device 23 drives the driving motor 21 by the driving motor control device 22 to rotate the work roller at a predetermined rotational speed and in a predetermined rotational direction (S120). As described above, the rotation speed and the rotation direction as the roller rotation conditions are set in advance, and the driving motor control device 22 rotates the upper work roller 1 and the lower work roller 2 under the set roller rotation conditions. The rotation direction of each work roll 1, 2 in step S120 is the normal rotation direction. When the work rolls 1 and 2 rotate, the depressing direction loads on the working side and the driving side are detected by the depressing direction load detecting devices 28a and 28b and the depressing direction load detecting devices 29a and 29b, respectively, and output to the depressing direction load difference calculating section 32 and the depressing direction load difference calculating section 33.

The up-depressing-direction load difference calculating section 32 and the depressing-direction load difference calculating section 33 calculate a depressing-direction load difference, which is a difference between a depressing-direction load on the working side and a depressing-direction load on the driving side, when receiving an input of the depressing-direction load. The calculated load difference in the pressing direction at the time of normal rotation of the roller is input to the inter-roller intersection control device 23 and set to a reference value 2 (corresponding to the "second reference value" of the present invention) (S122).

When the reference value 2 is calculated, the rotation direction of the work roll is then reversed, and the process at the time of roll reversal is started. The inter-roller intersection control device 23 drives the driving motor 21 by the driving motor control device 22 to rotate the work roller at a predetermined rotational speed and in a predetermined rotational direction (S124). When the work roll rotates, similarly to the case of normal rotation of the roll, the pressing-down direction load detection means 28a and 28b and the pressing-down direction load detection means 29a and 29b detect the pressing-down direction loads on the work side and the drive side, respectively, and output the detected loads to the pressing-down direction load difference calculation unit 32 and the pressing-down direction load difference calculation unit 33. The rotation direction of each work roll 1, 2 in step S124 is set to the reverse direction.

The up-pressing-direction load difference calculating unit 32 and the pressing-down-direction load difference calculating unit 33 each calculate a pressing-down-direction load difference, which is a difference between the pressing-down-direction load on the working side and the pressing-down-direction load on the driving side, when receiving the input of the pressing-down-direction load, and output the calculated pressing-down-direction load difference when the rollers are reversed to the inter-roller intersection control device 23. Then, the inter-roller cross control device 23 calculates second control target values for the upper roller system and the lower roller system, respectively, based on the difference between the load difference in the pressing direction when the rollers are reversed and the reference value 2 calculated in step S122 (S126). The second control target value is, for example, a value half the deviation from the reference value 2. Further, there is a case where a difference occurs in the characteristic of load difference in the pressing-down direction in the acting direction of the thrust at the time of normal rotation and reverse rotation due to the influence of sliding resistance between the roller bearing holder and the housing, a bearing gap, and the like. In this case, the second control target value may be set according to the degree of difference in magnitude of the load difference in the depressing direction between the normal rotation and the reverse rotation based on the result of the recognition in advance. That is, the second control target value may be a value other than half the deviation from the reference value 2.

After the second control target value is calculated, the depressing direction load on the working side and the depressing direction load on the driving side at the time of the roll reverse rotation are measured for each of the upper roll system and the lower roll system, and the depressing direction load difference is calculated as the difference (S128). Then, the inter-roller cross control device 23 compares the pressing-down direction load difference at the time of roller reverse rotation calculated in step S128 with the second control target value calculated in step S126, and determines whether or not they match (S130). The determination in step S130 includes not only a case where the pressing-down direction load difference at the time of the roller reverse rotation completely matches the second control target value, but also a case where the deviation of the pressing-down direction load difference at the time of the roller reverse rotation from the second control target value falls within a predetermined range. When it is determined in step S130 that the load difference in the pressing direction at the time of the roller reverse rotation is not the second control target value or is not within the allowable range, the inter-roller intersection control device 23 instructs the roller chock position control device 16 to adjust the position of the work roller chock of the roller system that does not satisfy the requirement of step S130 (S132). Then, when the position of the work roll chock is adjusted, the processing from step S128 is executed again.

When it is determined in step S130 that the pressing direction load difference at the time of the roll reversal coincides with the second control target value or falls within the allowable range, it is assumed that the inter-roll intersection control device 23 adjusts the inter-roll intersection of the upper reinforcing roll 3, the upper work roll 1, the lower work roll 2, and the lower reinforcing roll 4 within the allowable range, and the inter-roll intersection control device 23 adjusts the pressing device 27 so that the nip between the upper work roll 1 and the lower work roll 2 becomes a predetermined size (S134). Thereafter, the rolling mill starts rolling the material to be rolled or the rolling position zero point adjustment.

(calculation of reference value 2 and second control target value)

Here, the calculation of the reference value 2 and the second control target value will be described in detail based on fig. 4B. In the second adjustment, a mutual pressing ( め Write み) load is applied in a roller contact state in which the upper and lower work rollers are in contact with each other, and the positions of the work roller on the opposite side of the reference roller and the reinforcing roller bearing seat are controlled so that the difference in pressing direction load caused by the thrust between the upper and lower work rollers in this state becomes a predetermined target value.

First, as shown in the upper side of fig. 4B, in the roller contact state, the rollers are rotated in the normal direction in the upper roller system composed of the upper work roller 1 and the upper reinforcing roller 3 and the lower roller system composed of the lower work roller 2 and the lower reinforcing roller 4, respectively. Then, the depressing direction load on the working side and the depressing direction load on the driving side of the upper roll system, and the depressing direction load on the working side and the depressing direction load on the driving side of the lower roll system were measured. Based on the measured values, a difference in load in the depressing direction, which is a difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side, is calculated for each of the upper and lower roller systems (P21, P22). The load difference in the rolling direction of each roll system was calculated by the following formula (3).

[ number 3]

Here, P is_df2 ^TIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the upper roll system in the normal rotation state of the rolls in the roll contact state (upper reference value 2)^T)，P_df2 ^BIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the lower roll system in the normal rotation state of the rolls in the roll contact state (lower reference value 2)^B). The reference value 2 in step S122 is the upper reference value 2^TAnd a lower reference value of 2^B。

Next, the rotation of the roller is reversed in the roller-contact state, and the second control target value is calculated from the measured values of the rolling direction loads on the upper and lower working sides and the driving side, and the reference value 2 calculated by the above equation (3). Similarly to the first control target value, the second control target value may be a control target value (second control target value) of 1/2 of a deviation from a reference in the roller reverse rotation state when the roller normal rotation state is set as the reference, which is a difference in the depressing direction load between the upper and lower work rollers and the reinforcing roller where the thrust force becomes zero. That is, the second control target value can be expressed by the following formula (4).

[ number 4]

Herein, P'_dfT2 ^TIs a second control target value, P'_dfT2 ^BIs a second control target value of the lower roll system. This makes it possible to calculate the second control target values of the upper roll system and the lower roll system. In addition, although the above calculation has been described as a method of calculating the load in the rolling direction of both the upper and lower rolls, in the second adjustment, the load in the rolling direction is a difference in the load in the rolling direction due to the thrust between the upper and lower work rolls in a state where the upper and lower work rolls are in contact with each other, and therefore the influence of the intersection between the rolls appears similarly in both the upper and lower directions. Therefore, in this case, the positions of the work roll and the reinforcing roll bearing seats on the opposite side of the reference roll may be controlled using at least one of the upper and lower values (P23 in fig. 4B).

Here, although equation (4) is defined so that the magnitude of the load difference in the pressing direction is substantially the same between the normal rotation of the roller and the reverse rotation of the roller, there may be a difference in the characteristic of the load difference in the pressing direction in the acting direction of the thrust force between the normal rotation and the reverse rotation due to the influence of the sliding resistance between the roller bearing holder and the housing, the bearing gap, and the like. In this case, the second control target value may be set according to the degree of difference in magnitude of the load difference in the depressing direction between the normal rotation and the reverse rotation based on the result of the recognition in advance. That is, the second control target value may be a value other than half the deviation from the reference value 2.

[2-3. conclusion ]

The rolling mill according to the first embodiment of the present invention and the setting method of the rolling mill have been described above. According to the present embodiment, the control target value for making the cross angle between the rolls zero is calculated and set based on the load difference in the rolling direction by using the fact that the magnitude of the load difference in the rolling direction is substantially the same but the direction is opposite between the normal rotation of the rolls and the reverse rotation of the rolls, and the first adjustment and the second adjustment are performed before the zero point adjustment of the rolling position or before the start of rolling. Thus, the material to be rolled is rolled while eliminating the intersection angle between the rolls, and therefore, the occurrence of meandering and warping of the material to be rolled can be suppressed.

<3 > second embodiment

Next, a method of setting a rolling mill according to a second embodiment of the present invention will be described with reference to fig. 7A to 8B. In the present embodiment, as in the first embodiment, before the adjustment of the zero point of the rolling position or before the start of rolling, the adjustment is performed so that the intersection angle between the reinforcing roll and the other roll, which is set as the reference, becomes zero, thereby realizing rolling without generating thrust. The rolling mill according to the present embodiment can also adjust the intersection between the rolls even when the thrust reaction force cannot be measured, as in the first embodiment. The rolling mill and the device for controlling the rolling mill according to the present embodiment can be configured in the same manner as the rolling mill and the control device according to the first embodiment shown in fig. 2. Therefore, detailed description thereof will be omitted in the present embodiment.

[3-1. setting method of Rolling Mill ]

Fig. 7A and 7B are flowcharts for explaining a setting method of a rolling mill according to the present embodiment, and show an example of a case where position adjustment is performed based on a load in a rolling direction when a roll is stopped and when a roll is rotated. Fig. 8A is an explanatory diagram illustrating a procedure of position adjustment of the roller bearing seat in the setting method of the rolling mill according to the present embodiment, and illustrates the position adjustment in the nip open state. Fig. 8B is an explanatory diagram illustrating a procedure of adjusting the position of the roller bearing seat in the setting method of the rolling mill according to the present embodiment, and illustrates the position adjustment in the roller contact state. In fig. 7A and 7B, the distribution of the load acting between the rollers is not shown. In this example, the lower reinforcing roller 4 is described as the reference roller, but the reference roller may be either the uppermost roller or the lowermost roller in the depressing direction, or the upper reinforcing roller 3 may be the reference roller.

In the setting method of the rolling mill according to the present embodiment, when the nip between the upper work roll 1 and the lower work roll 2 is opened and when the rolls are in contact with each other, the load difference in the rolling direction is calculated from the driving-side and working-side load in the rolling direction detected by the load detection devices 28a and 28b in the rolling direction, and the load difference in the rolling direction is calculated from the driving-side and working-side load in the rolling direction detected by the load detection devices 29a and 29b in the rolling direction. Then, the position of the roll chocks is adjusted based on the calculated load difference in the rolling direction, so that the roll-to-roll intersection of the rolls of the rolling mill falls within a predetermined range. In this case, the control target value for adjusting the position of the roll chocks can be derived using the rolling direction loads on the working side and the driving side of the upper roll system and the lower roll system measured when the rolls are stopped and rotated. At this time, the rolling direction position of the roll chocks of the reference rolls is fixed as a reference position, and the positions of the roll chocks of the rolls other than the reference rolls are adjusted by moving the positions in the rolling direction. The following describes the details.

(A) First adjustment: position adjustment in the open state of the roll gap (S200-S214)

In the first adjustment for adjusting the position in the nip open state, the upper work roll and the lower work roll are opened and an increased bending force is applied to provide a load between the work roll and the reinforcing roll, and in this state, the upper and lower work roll chock positions are controlled so that the difference in the load in the pressing direction due to the thrust between the rolls becomes a predetermined target value. First, as shown in fig. 7A, the inter-roll intersection control device 23 causes the press-down device 27 to adjust the roll position in the press-down direction so that the nip between the upper work roll 1 and the lower work roll 2 is opened with a predetermined gap (S200). The press device 27 applies a predetermined load to the rollers based on the instruction, and opens the nip between the work rollers 1 and 2.

The inter-roller-crossing control device 23 instructs the bending-increase control device 26 to apply a predetermined bending-increase force to the work-roller chocks 5 and 6 by the bending-increase devices 24a, 24b, 25a, and 25b (S202). The bend-increasing controller 26 controls the bend-increasing devices 24a, 24b, 25a, and 25b based on the instruction to apply a predetermined bend-increasing force to the work roll chocks 5 and 6. This makes it possible to provide a predetermined load only between the upper and lower work rolls and the reinforcing roll without causing a load action between the upper and lower work rolls. In the case where the bending apparatus has a function of a balancer for lifting the weight of the work rolls, the order of step S200 and step S202 may be reversed, that is, the gap between the upper and lower work rolls may be adjusted after the bending force is increased.

Subsequently, the inter-roller intersection control device 23 brings the rollers into a state in which the rotation is stopped (S204). Then, in the roller stopped state, the pressing-down direction loads on the working side and the driving side are detected by the pressing-down direction load detecting devices 28a and 28b and the pressing-down direction load detecting devices 29a and 29b, respectively, and output to the pressing-down direction load difference calculating section 32 and the pressing-down direction load difference calculating section 33. The up-depressing-direction load difference calculating section 32 and the depressing-direction load difference calculating section 33 calculate a depressing-direction load difference, which is a difference between a depressing-direction load on the working side and a depressing-direction load on the driving side, when receiving an input of the depressing-direction load. The calculated load difference in the pressing direction when the roller is stopped is input to the inter-roller intersection control device 23, is set to a reference value 1 (corresponding to the "first reference value" of the present invention), and a first control target value is calculated based on the reference value 1 (S206).

When the first control target value is calculated, the upper work roll 1 and the lower work roll 2 are rotated, and the process at the time of the roll rotation is started. The inter-roller intersection control device 23 drives the driving motor 21 by the driving motor control device 22 to rotate the work roller at a predetermined rotational speed and in a predetermined rotational direction (S208). When the work roll rotates, the pressing-down direction loads on the work side and the drive side are detected by the upper pressing-down direction load detecting devices 28a and 28b and the lower pressing-down direction load detecting devices 29a and 29b, respectively, and output to the upper pressing-down direction load difference calculating unit 32 and the lower pressing-down direction load difference calculating unit 33. When receiving the input of the depressing direction load, the upward depressing direction load difference calculating section 32 and the depressing direction load difference calculating section 33 each calculate a depressing direction load difference, which is a difference between the depressing direction load on the working side and the depressing direction load on the driving side, and output the calculated depressing direction load difference at the time of rotation of the roller to the inter-roller intersection control device 23 (S210).

The inter-roller cross control device 23 compares the load difference in the pressing direction during rotation of the roller calculated in step S210 with the first control target value calculated in step S206, and determines whether or not they match (S212). The determination in step S212 includes not only a case where the difference in load in the pressing direction during the rotation of the roller completely matches the first control target value, but also a case where the difference in load in the pressing direction during the rotation of the roller is within a predetermined range from the first control target value. When it is determined in step S212 that the difference in load in the pressing direction during rotation of the roller is not the first control target value or is not within the allowable range, the inter-roller intersection control device 23 instructs the roller chock position control device 16 to adjust the position of the work roller chock of the roller system that does not satisfy the requirements of step S212 (S214). Then, when the positions of the upper and lower work roll chocks are adjusted, the process from step S210 is executed again. In this case, the position of the upper reinforcing roll chock may be controlled instead of the upper work roll chock, so as to reduce the differential load generated by the thrust between the upper work roll and the reinforcing roll.

When it is determined in step S212 that the load difference in the pressing direction at the time of the roller reverse rotation coincides with the first control target value or falls within the allowable range thereof, the inter-roller intersection control device 23 proceeds to the processing shown in fig. 7B.

(calculation of reference value 1 and first control target value)

Here, calculation of the reference value 1 and the first control target value will be described in detail based on fig. 8A. First, as shown in the upper side of fig. 8A, in the nip open state, the rotation of the rolls is stopped in the upper roll system composed of the upper work roll 1 and the upper reinforcing roll 3 and the lower roll system composed of the lower work roll 2 and the lower reinforcing roll 4, respectively. At this time, since the upper work roll 1 and the lower work roll 2 are separated, the respective roll systems are in an independent state. In this roller stopped state, the depressing direction load on the working side and the depressing direction load on the driving side of the upper roller system, and the depressing direction load on the working side and the depressing direction load on the driving side of the lower roller system are measured. Then, the difference between the load in the working direction and the load in the driving direction, that is, the difference in load in the depressing direction, is calculated for each of the upper and lower roller systems based on the measured values (P31, P32). The load difference in the rolling direction of each roll system was calculated by the following formula (5).

[ number 5]

Here, P is⁰ _df1 ^TIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the upper roll system in the stopped state of the rolls (upper reference value 1)^T)，P⁰ _df1 ^BIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the lower roll system in the stopped state of the rolls (lower reference value 1)^B). The reference value 1 in step S206 is the upper reference value 1^TAnd a lower reference value of 1^B. In addition, P⁰ _W ^TIs a measured value of the load in the pressing direction on the working side of the upper roll system in the stopped state of the rolls, P⁰ _W ^BThe measured value of the load in the pressing direction on the working side of the lower roll system in the roll stopped state. And, P⁰ _D ^TIs a measured value of the load in the pressing direction on the driving side of the upper roll system in the stopped state of the rolls, P⁰ _D ^BThe measured value of the load in the pressing direction on the driving side of the lower roll system in the stopped state of the rolls.

Then, the first control target value is set based on the reference value 1. Here, when the first control target value is calculated, the relationship between the load difference in the pressing direction when the roller is stopped and when the roller is rotated is examined. In the above-described investigation, for example, as shown in fig. 9, in a rolling mill having the same configuration as that of fig. 5, the upper work roll 1 and the lower work roll 2 are separated, and the nip between the work rolls 1 and 2 is set to an open state. In a state where the work rolls 1 and 2 are separated from each other, an increasing bending force is applied to the upper work roll chocks 5a and 5b and the lower work roll chocks 6a and 6b by an increasing bending device (not shown).

When the lower work roll 2 and the lower reinforcing roll 4 are rotated with a cross angle between the rolls being generated between the lower work roll 2 and the lower reinforcing roll 4, as shown in fig. 9, a thrust force is generated between the lower work roll 2 and the lower reinforcing roll 4, and a moment is generated in the lower reinforcing roll 4. Due to this moment, the load detected by the drive-side load detection device 10b becomes larger than the load detected by the work-side load detection device 10a, and a load difference in the load in the pressing direction occurs. On the other hand, in a state where the rollers are stopped, since relative sliding in the roller axis direction does not occur between the lower work roller 2 and the lower reinforcing roller 4, an inter-roller thrust force is not generated. Therefore, the depressing direction load detecting devices 10a and 10b detect the depressing direction load that is not affected by the thrust force between the rollers.

Fig. 10 shows a change in the difference in the load difference in the pressing direction, which is the difference in the load in the pressing direction detected between the driving side and the working side when the roller is stopped and when the roller is rotated. A predetermined roll intersection angle is set between the lower work roll 2 and the lower reinforcing roll 4, and a rolling-down direction load in a state where the rolls are stopped is detected, and then the rolls are rotated to detect the rolling-down direction load. Fig. 10 is one measurement result obtained by detecting a change in the difference in load in the pressing direction between the normal rotation of the rolls and the reverse rotation of the rolls when the inter-roll intersection angle of the lower work rolls is changed by 0.1 ° toward the exit side of the drive side in a small rolling mill having a work roll diameter of 80 mm. The bending increasing force applied to each work roll bearing block was set to 0.5 tonf/chock. As shown in fig. 10, the load difference in the pressing direction when the roller is rotated is made larger in the negative direction than the load difference in the pressing direction when the roller is stopped. In this way, the difference in load in the pressing direction is different between when the roller is stopped and when the roller is rotated.

Since it is considered that the difference in load in the pressing direction occurring in the roller stopped state is caused by a factor other than the thrust force, the thrust force between the upper and lower work rollers and the reinforcing roller can be made zero by controlling the roller bearing seat position by setting the difference in load in the pressing direction in the roller stopped state as the first control target value with reference to the difference in load in the pressing direction. The first control target value is expressed by the following equation (6).

[ number 6]

Here, P is^r _dfT1 ^TIs a first control target value, P, of the upper roll system^r _dfT1 ^BIs a first control target value of the lower roll system. The rotation direction of the roller is not particularly limited, and the rotation of the roller may be either normal rotation or reverse rotation. This makes it possible to calculate the first control target values of the upper and lower roll systems.

The driving of the roller bearing seat position during the rotation of the roller is directed to the roller bearing seats of the rollers other than the reference roller. That is, the upper roll system can control the position of the upper work roll chock as shown in the center of fig. 8A (P33), and can control the position of the upper stiffening roll chock as shown in the lower side of fig. 8A (P35). On the other hand, in the lower roll system, the lower reinforcing roll 4 is stationary because it is a reference roll, and the position of the lower work roll chock is controlled as shown in the center and the lower side of fig. 8A (P34, P36).

(B) And (3) second adjustment: position adjustment in the roller contact state (S216-S230)

Returning to the description of the flowchart, when the position adjustment of the nip in the open state shown in fig. 7A is completed, the inter-roller cross control device 23 then causes the press-down device 27 to adjust the roller position in the pressing-down direction so that the nip between the upper work roller 1 and the lower work roller 2 is in a predetermined roller contact state as shown in fig. 7B (S216). The press device 27 brings the work rollers 1 and 2 into contact with each other by applying a predetermined load to the rollers based on the instruction, thereby bringing the rollers into contact with each other.

Subsequently, the inter-roller cross control device 23 stops the rotation of the rollers (S218). Then, in the roller stopped state, the pressing-down direction loads on the working side and the driving side are detected by the pressing-down direction load detecting devices 28a and 28b and the pressing-down direction load detecting devices 29a and 29b, respectively, and output to the pressing-down direction load difference calculating section 32 and the pressing-down direction load difference calculating section 33. The up-depressing-direction load difference calculating section 32 and the depressing-direction load difference calculating section 33 calculate a depressing-direction load difference, which is a difference between a depressing-direction load on the working side and a depressing-direction load on the driving side, when receiving an input of the depressing-direction load. The calculated load difference in the pressing direction when the roller is stopped is input to the inter-roller intersection control device 23, is set to a reference value 2 (corresponding to the "second reference value" of the present invention), and a second control target value is calculated based on the reference value 2 (S220).

When the second control target value is calculated, the upper work roll 1 and the lower work roll 2 are rotated, and the process at the time of the roll rotation is started. The inter-roller intersection control device 23 drives the driving motor 21 by the driving motor control device 22 to rotate the work roller at a predetermined rotational speed and in a predetermined rotational direction (S222). When the work roll rotates, the pressing-down direction loads on the work side and the drive side are detected by the upper pressing-down direction load detecting devices 28a and 28b and the lower pressing-down direction load detecting devices 29a and 29b, respectively, and output to the upper pressing-down direction load difference calculating unit 32 and the lower pressing-down direction load difference calculating unit 33. When receiving the input of the depressing direction load, the upward depressing direction load difference calculating section 32 and the depressing direction load difference calculating section 33 each calculate a depressing direction load difference, which is a difference between the depressing direction load on the working side and the depressing direction load on the driving side, and output the calculated depressing direction load difference at the time of rotation of the roller to the inter-roller intersection control device 23 (S224).

The inter-roller cross control device 23 compares the pressing-down direction load difference during the rotation of the roller calculated in step S224 with the second control target value calculated in step S220, and determines whether or not they match (S226). The determination at step S226 includes not only a case where the pressing-down direction load difference during the rotation of the roller completely matches the second control target value, but also a case where the deviation of the pressing-down direction load difference during the rotation of the roller from the second control target value falls within a predetermined range. When it is determined in step S226 that the difference in load in the pressing direction during rotation of the roller is not the second control target value or is not within the allowable range, the inter-roller intersection control device 23 instructs the roller chock position control device 16 to adjust the position of the work roller chock of the roller system that does not satisfy the requirement of step S226 (S228). Then, when the position of the work roll chock is adjusted, the processing from step S224 is executed again.

Then, when it is determined in step S226 that the pressing direction load difference at the time of the roller reverse rotation is equal to the second control target value or within the allowable range, it is regarded that the inter-roller intersection control device 23 adjusts the inter-roller intersection of the upper reinforcing roller 3, the upper work roller 1, the lower work roller 2, and the lower reinforcing roller 4 within the allowable range, and the pressing device 27 is adjusted so that the nip between the upper work roller 1 and the lower work roller 2 becomes a predetermined size (S230). Thereafter, the rolling mill starts rolling the material to be rolled or the rolling position zero point adjustment.

(calculation of reference value 2 and second control target value)

Here, the calculation of the reference value 2 and the second control target value will be described in detail based on fig. 8B. In the second adjustment, a mutual pressing load is applied in a roller contact state in which the upper and lower work rollers are in contact with each other, and the positions of the work roller and the reinforcing roller bearing seat on the opposite side of the reference roller are controlled so that a difference in load in the pressing direction due to the thrust between the upper and lower work rollers in this state becomes a predetermined target value.

First, as shown in the upper side of fig. 8B, in the roller contact state, the rotation of all the rollers is stopped, and the depressing direction load on the working side and the depressing direction load on the driving side of the upper roller system, and the depressing direction load on the working side and the depressing direction load on the driving side of the lower roller system are measured. Then, the difference between the load in the working direction and the load in the driving direction, that is, the difference in load in the depressing direction, is calculated for each of the upper and lower roller systems based on the measured values (P41, P42). The load difference in the rolling direction of each roll system was calculated by the following formula (7).

[ number 7]

Here, P is⁰ _df2 ^TIs the difference between the measured values of the load in the pressing direction of the upper roll system on the working side and the driving side in the roll-stopped state in the roll-contact state (upper reference value 2)^T)，P⁰ _df2 ^BIs the difference between the measured values of the load in the pressing direction between the working side and the driving side of the lower roll system in the roll-stopped state in the roll-contact state (lower reference value 2)^B). The reference value 2 in step S220 is the upper reference value 2^TAnd a lower reference value of 2^B。

Next, the roller is rotated in a roller-contact state, and a second control target value is calculated from the measured values of the rolling-down direction loads on the upper and lower working sides and the driving side, and the reference value 2 calculated by the above equation (7). The second control target value can be a control target value (second control target value) in which the thrust between the upper and lower work rolls is zero with the roll stop state as a reference, as in the case of the first control target value. The second control target value can be represented by the following formula (8).

[ number 8]

Here, P is^r _dfT2 ^TIs a second control target value, P, of the upper roll system^r _dfT2 ^BIs a second control target value of the lower roll system. In addition, although the above calculation has been described as a method of calculating the load in the rolling direction of both the upper and lower rolls, in the second adjustment, the load in the rolling direction is a difference in the load in the rolling direction due to the thrust between the upper and lower work rolls in a state where the upper and lower work rolls are in contact with each other, and therefore the influence of the intersection between the rolls appears similarly in both the upper and lower directions. Therefore, in this case, the positions of the work roll and the reinforcing roll bearing seats on the opposite side of the reference roll may be controlled using at least one of the upper and lower values (P43).

[3-2. conclusion ]

The method for setting a rolling mill according to the second embodiment of the present invention has been described above. According to the present embodiment, the control target value for making the cross angle between the rolls zero in accordance with the rolling direction load difference is calculated and set on the basis of the rolling direction load difference that does not occur when the rolls are stopped but occurs when the rolls are rotated, and the first adjustment and the second adjustment are performed before the rolling position zero point adjustment or before the rolling start. Thus, the material to be rolled is rolled while eliminating the intersection angle between the rolls, and therefore, the occurrence of meandering and warping of the material to be rolled can be suppressed.

<4. relationship between crossing angle between rolls and load difference in pressing direction >

In the setting method of the rolling mill according to the first and second embodiments, the position of the roll chocks is controlled so that the thrust reaction force generated between the rolls is zero or a value within an allowable range in order to eliminate the intersection between the rolls. This is based on the finding that there is a correlation between the thrust reaction force and the intersection angle between the rollers as shown below. Next, the relationship between the crossing angle between the rollers and the load difference in the pressing direction will be described with reference to fig. 11 to 15.

[4-1. relationship in the nip open State ]

First, the relationship between the roll intersection and the load difference in the pressing direction when the nip of the work rolls is opened will be described with reference to fig. 11 to 13. Fig. 11 is an explanatory diagram showing the arrangement of the work rolls 1, 2 and the reinforce rolls 3, 4 of the rolling mill with the nip open. Fig. 12 is an explanatory diagram showing the definition of the intersection angle between the rollers. FIG. 13 is a graph showing a relationship between a cross angle of a reinforcing roll and a load difference in a rolling direction in a nip-opened state, which is an experimental result obtained by an experiment performed in a small rolling mill having a work roll diameter of 80 mm. Fig. 13 shows values obtained by averaging the measured values in the increasing direction and the measured values in the decreasing direction, in which the load difference in the depressing direction of the upper and lower reinforcing rolls is measured for the case where the reinforcing roll intersection angle is set in the increasing direction and the case where the reinforcing roll intersection angle is set in the decreasing direction.

As shown in fig. 11, the nip between the upper work roll 1 and the lower work roll 2 is opened, and the increased bending force is applied to the work roll chock by the increased bending device. Further, changes in load difference in the pressing direction when the intersection angle of the upper reinforcing roll 3 and the lower reinforcing roll 4 was changed were examined. As shown in FIG. 12, the crossing angle of the reinforcing roller is the roller axis A extending in the roller body length direction_rollThe direction from the width direction (X direction) toward the exit side of (b) is positive. In addition, the increasing bending force was set to 0.5tonf per 1 roller chock.

As a result, as shown in fig. 13, the following relationship is found: when the intersection angle between the upper reinforcing roll 3 and the lower reinforcing roll 4 is increased from a negative angle to a zero angle and a positive angle, the value of the load difference in the pressing direction is decreased. At this time, it was confirmed that when the intersection angle of the reinforcing rollers was zero, the value of the load difference in the depressing direction was also zero. Therefore, in a state where the nip is opened and the bending force is increased, the influence of the thrust force due to the intersection angle between the reinforcing roll and the work roll of each roll system can be grasped from the load difference in the pressing direction. Further, it is known that the thrust between the rollers can be reduced by controlling the positions of the roller bearing housings so that these values become zero.

[4-2 relationship in the roller contact State ]

Next, the relationship between the pair crossing angle of the rollers and the load difference in the pressing direction when the work roller is in the roller contact state will be described with reference to fig. 14 and 15. Fig. 14 is an explanatory diagram showing the arrangement of the work rolls 1, 2 and the reinforce rolls 3, 4 of the rolling mill set in the roll contact state. Fig. 15 is a graph showing a relationship between a pair intersection angle of the work roll and the reinforce roll and a load difference in the depressing direction in the roll contact state. In fig. 15, the rolling direction load difference between the upper and lower reinforcing rolls is measured for each of the case where the paired intersection angle between the work roll and the reinforcing roll is set in the increasing direction and the case where the paired intersection angle between the work roll and the reinforcing roll is set in the decreasing direction, and the measured values in the increasing direction and the measured values in the decreasing direction are averaged to obtain a value.

Here, as shown in fig. 14, changes in load difference in the pressing direction when the pair of intersection angles of the work roll and the reinforcing roll were changed while the upper work roll 1 and the lower work roll 2 were brought into contact with each other were examined. At this time, the roller contact mutual pressing load was set to 6.0 tonf.

As a result, as shown in fig. 15, when the pair crossing angle is increased from a negative angle to a zero or positive angle in order, the load difference in the depressing direction changes in accordance with the change in the pair crossing angle, and when the pair crossing angle is zero, the load difference in the depressing direction is also zero. Thus, in a state where a roller contact mutual pressing load is applied, the influence of the thrust force due to the intersection between the upper and lower work rollers can be detected from the load difference in the pressing direction. Further, it was confirmed that there is a possibility that: the thrust between the upper and lower work rolls can be reduced by controlling the roll chock positions so that these values become zero by integrating the upper and lower work rolls and the reinforcing roll.

Example 1

The fifth to seventh stands of the hot finishing mill having the structure shown in fig. 2 were compared with the method of the present invention with respect to the setting of the screw-down leveling considering the influence of the thrust force between the rolls generated by the intersection between the rolls.

First, in the conventional method, the function of the inter-roller intersection control device of the present invention is not used, and the casing pad and the bearing block pad are periodically replaced, and the facility management is performed so that the inter-roller intersection does not occur. As a result, when a thin and wide material having a machined side plate thickness of 1.2mm and a width of 1500mm was rolled immediately before the replacement of the shell gasket, meandering of 100mm or more occurred in the sixth stand, and pressing due to the meandering occurred (japanese patent No. り Write み).

On the other hand, in the method of the present invention, the thrust reaction force of each roll is measured in the state where the rolls are in contact with each other and pressed against each other using the function of the inter-roll intersection control device according to the first embodiment, and the positions of the roll bearing seats of each roll are controlled so that the difference in the rolling direction load before rolling falls within the preset allowable range in accordance with the processing flow shown in fig. 3A and 3B. As a result, even when a thin and wide material having a side plate thickness of 1.2mm and a width of 1500mm, which is extruded by a conventional method, is rolled at a time immediately before replacement of the shell liner, meandering of 12mm or less occurs, and the material to be rolled can be passed through the rolling line without being extruded.

As described above, in the method of the present invention, the rolling direction load difference, which is the difference between the rolling direction loads on the work side and the drive side measured before rolling, is calculated, and the roll chock positions of the rolls are controlled with respect to the reference roll based on an appropriate logic so that the rolling direction load difference falls within an allowable range, thereby eliminating the roll-to-roll intersection itself and eliminating the left-to-right asymmetric deformation of the rolled material caused by the thrust force due to the roll intersection. Thus, a metal plate material free from meandering and warping, or having extremely slight meandering and warping can be stably produced.

Example 2

Next, the press leveling setting considering the influence of the thrust generated by the intersection between the rollers was compared between the conventional method and the method of the present invention.

First, in the conventional method, the function of the inter-roller intersection control device of the present invention is not used, and the casing pad and the bearing block pad are periodically replaced, and the facility management is performed so that the inter-roller intersection does not occur.

On the other hand, in the method of the present invention, the position of the roll bearing housing is adjusted before rolling according to the processing flow shown in fig. 7A and 7B using the function of the inter-roll intersection control device according to the second embodiment. That is, first, in a state where the nip is opened and a large bending force is applied, the pressing-down direction load is measured in a state where the rotation of the roller is stopped and stopped, and the positions of the upper and lower work roll chocks are controlled. Then, the roll contact state is set, the rolling direction load is measured in the stopped and stopped state of the rotation of the roll, and the positions of the roll chocks of the upper and lower work rolls and the reinforcing roll are controlled so that the difference in the rolling direction load during the rotation falls within a predetermined allowable range.

Table 1 shows the actual measured values of the occurrence of warp corresponding to the representative rolling number with respect to the present invention and the conventional method. When the actual warp value per 1m of the leading end of the rolled material is observed, that is, the reinforcing rolls are to be rearranged and the shell liner is to be replaced, in the case of the present invention, it is found that the warp value is suppressed to a relatively small value of 0.12 mm/m. In contrast, in the case of the conventional method, the actual warp value becomes larger at the time when the reinforcing roller is to be rearranged and the casing liner is to be replaced, as compared with the case of the present invention.

[ Table 1]

TABLE 1

As described above, in the method of the present invention, before rolling, the rolling direction load difference is calculated, and the bearing seat position of each roll is controlled with respect to the reference roll based on an appropriate logic so that the rolling direction load difference falls within the allowable range, whereby the inter-roll intersection itself can be eliminated, and the left-right asymmetric deformation of the rolled material due to the thrust force caused by the inter-roll intersection can be eliminated. Thus, a metal plate material free from meandering and warping, or having extremely slight meandering and warping can be stably produced.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, but the present invention is not limited to the examples. It is needless to say that various modifications and alterations can be made by those who have ordinary knowledge in the technical field to which the present invention pertains within the scope of the technical idea described in the claims, and it is needless to say that these modifications and alterations also fall within the technical scope of the present invention.

For example, in the above-described embodiment, as shown in fig. 2, for example, a driving device having a roll chock position detection function for detecting the position of the work roll chock in the rolling direction is used, but the present invention is not limited to the above-described example. For example, the position of the work roll chock in the rolling direction can be measured by using a servomotor with a rotation angle detection function instead of the roll chock position detection device. That is, as in the upper work roll 1 and the upper work roll chock 5 shown in fig. 16, the servomotor 34 with a rotation angle detection function may be provided so as to face the driving device 11 with an on-belt work roll chock position detection function in the rolling direction of the upper work roll chock 5. In addition, the bending device may be a hydraulic jack as long as it applies a force in the pressing direction.

In the above description, the example in which the load detection means in the pressing direction is provided in the upper and lower sides has been described, but the present invention is not limited to the above example. For example, in the case where the load detection device in the depressing direction is disposed only on the upper and lower sides, the same control can be performed by omitting the first adjustment with respect to the side without the load detection device, while sufficiently managing and regarding that the roller minor intersection is small.

In the above embodiment, the 4-high rolling mill including the pair of work rolls and the pair of stiffening rolls has been described, but the present invention can be applied to a rolling mill having 4 or more rolls. For example, in the case of a 6-roll mill, a reference roll to be used as a reference is set for the position adjustment of the roll chocks, and in this case, a roll positioned at the lowermost portion or the uppermost portion among the rolls aligned in the rolling direction may be used as the reference roll.

For example, as shown in fig. 17A, a 6-roll rolling mill is provided with intermediate rolls 41 and 42 between work rolls 1 and 2 and reinforcing rolls 3 and 4, respectively. The upper intermediate roll 41 is supported by an upper intermediate roll chock 43a on the work side and an upper intermediate roll chock 43b on the drive side (the upper intermediate roll chocks 43a, 43b are also collectively referred to as "upper intermediate roll chock 43"). The lower intermediate roller 42 is supported by a lower intermediate roller bearing support 44a on the work side and a lower intermediate roller bearing support 44b on the drive side (the lower intermediate roller bearing supports 44a, 44b are also collectively referred to as "lower intermediate roller bearing supports 44"). Further, the upper intermediate roll chock 43 and the lower intermediate roll chock 44 are sometimes also simply referred to as roll chocks. In the case of the 6-high rolling mill, for example, as shown in fig. 17A to 17C, the roll chock position can be adjusted by performing the 3-stage adjustment step as in the case of the 4-high rolling mill.

Specifically, in the adjustment of the roller bearing seat positions, as a first adjustment, the positions of the roller bearing seats 43, 44 of the intermediate rollers 41, 42 and the roller bearing seats 43, 44, 7, 8 of the reinforcing rollers 3, 4 are adjusted for the upper roller system and the lower roller system, respectively, in a state where the nip of the work rollers 1, 2 is opened and the bending force is applied to the roller bearing seats 43, 44 of the intermediate rollers 41, 42 by the bending device (fig. 17A). Next, as a second adjustment, the positions of the roller bearing blocks 43 and 44 of the intermediate rollers 41 and 42 and the roller bearing blocks 5 and 6 of the work rollers 1 and 2 are adjusted for the upper roller system and the lower roller system, respectively, while the nip of the work rollers 1 and 2 is maintained in an open state and the bending force is applied to the roller bearing blocks 5 and 6 of the work rollers 1 and 2 by the bending device (fig. 17B). Thereafter, as a third adjustment, the work rolls 1 and 2 are brought into contact with each other, and the positions of the roll chocks of the upper roll system and the lower roll system are adjusted (fig. 17C).

The first adjustment may be, for example, to calculate a load difference between the depressing direction load on the working side and the depressing direction load on the driving side in the case of rotating the working rolls 1 and 2 normally in the upper left direction in fig. 17A and in the case of rotating the working rolls 1 and 2 reversely in the lower side in fig. 17A, and calculate a control target value to adjust the position of the roll chock. This corresponds to the first adjustment in the case of the 4-high rolling mill shown in fig. 4A. In this case, first, the work rolls 1 and 2 are rotated (rotated forward), the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, and the reference value 1 is calculated from the load difference between the depressing direction load on the work side and the depressing direction load on the driving side (corresponding to the "first reference value" of the present invention). Next, the rotation directions of the work rolls 1 and 2 are reversed, the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, the load difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated, and the first control target value is calculated based on the deviation of the load difference from the reference value 1. Thereafter, either one of the roller bearing seats 43 of the intermediate roller 41 and the roller bearing seats 7 of the reinforcing roller 3 of the roller system on the side opposite to the reference roller, and the roller bearing seats 44 of the intermediate roller 42 on the side of the reference roller and the lower reinforcing roller 4 in fig. 17A are moved in the rolling direction to adjust the positions of the roller bearing seats so that the load difference becomes a value within the allowable range of the first control target value.

Alternatively, the first adjustment may be, for example, a load difference between the depressing direction load on the working side and the depressing direction load on the driving side in the case of stopping the working rolls 1 and 2 in the upper right of fig. 17A and in the case of rotating the working rolls 1 and 2 in the lower side of fig. 17A, and the position of the roll chock may be adjusted by calculating the control target value. This corresponds to the first adjustment in the case of the 4-high rolling mill shown in fig. 8A. In this case, first, in a state where the rotation of the work rolls 1 and 2 is stopped, the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, a reference value 1 is calculated from a load difference between the depressing direction load on the work side and the depressing direction load on the driving side, and the first control target value is set based on the reference value 1. Next, the work rolls 1 and 2 are rotated, and the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, and the difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated. Thereafter, either one of the roller bearing seats 43 of the intermediate roller 41 and the roller bearing seats 7 of the reinforcing roller 3 of the roller system on the opposite side to the reference roller, and the roller bearing seats 44 of the intermediate roller 42 on the side of the reference roller and the lower reinforcing roller 4 in fig. 17A are moved in the rolling direction to adjust the positions of the roller bearing seats so that the load difference is within the allowable range of the first control target value.

The second adjustment may be, for example, the difference between the load in the depressing direction on the working side and the load in the depressing direction on the driving side in the case of rotating the working rolls 1 and 2 in the normal direction on the upper left in fig. 17B and in the case of rotating the working rolls 1 and 2 in the reverse direction on the lower side in fig. 17B, and the position of the roll chock may be adjusted by calculating the control target value, similarly to the first adjustment. In this case, first, the work rolls 1 and 2 are rotated (rotated forward), the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, and the reference value 2 is calculated from the load difference between the depressing direction load on the work side and the depressing direction load on the driving side (corresponding to the "second reference value" of the present invention). Next, the rotation directions of the work rolls 1 and 2 are reversed, the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, the load difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated, and the second control target value is calculated from the deviation of the load difference from the reference value 2. Thereafter, the roller bearing holder 5 of the work roller 1 of the roller system on the side opposite to the reference roller, any one of the roller bearing holders 7 and 43 of the intermediate roller 41 and the reinforcing roller 3, and the roller bearing holder 6 of the work roller 2 on the side of the lower reinforcing roller 4 as the reference roller are moved in the rolling direction, and the positions of the roller bearing holders are adjusted so that the load difference becomes a value within the allowable range of the second control target value.

Alternatively, the second adjustment may be performed such that, for example, when the work rolls 1 and 2 are stopped at the upper right in fig. 17B and when the work rolls 1 and 2 are rotated at the lower side in fig. 17B, the difference between the load in the depressing direction on the work side and the load in the depressing direction on the drive side is calculated, and the control target value is calculated to adjust the position of the roll chock. In this case, first, in a state where the rotation of the work rolls 1 and 2 is stopped, the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, the reference value 2 is calculated from the load difference between the depressing direction load on the work side and the depressing direction load on the driving side, and the second control target value is set based on the reference value 2. Next, the work rolls 1 and 2 are rotated, and the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, and the difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated. Thereafter, the roll bearing blocks 5 of the work roll 1 of the roll system on the opposite side from the reference roll, any one of the roll bearing blocks 43 and 7 of the intermediate roll 41 and the reinforcing roll 3, and the roll bearing block 6 of the work roll 2 on the side of the lower reinforcing roll 4 as the reference roll are moved in the rolling direction to adjust the positional load difference of the roll bearing blocks so that the load difference becomes a value within the allowable range of the second control target value.

In the first adjustment, the bending devices of the intermediate rolls 41 and 42 are used, and a load is applied between the intermediate rolls 41 and 42 and the reinforcing rolls 3 and 4, so that the bending devices of the work rolls 1 and 2 apply zero force or a force in a degree balanced with the weight of the rolls. In this manner, in the case of the 6-high rolling mill, first, in the first adjustment, the position of the chock of the intermediate roll having the bending device or the reinforcing roll on the opposite side to the reference roll is adjusted by moving the position of the chock according to the intersection angle of the intermediate roll and the reinforcing roll. In the second adjustment, the bending devices of the intermediate rolls 41 and 42 apply zero force or force to an extent balanced with the weight of the rolls, and the bending devices of the work rolls are used as in the case of the 4-high rolling mill, and a load is applied between the work rolls and the intermediate rolls, and the roll chock positions of the work rolls or the intermediate rolls adjacent to the work rolls, and the roll chock positions of the intermediate rolls may be moved together with the roll chock of the reinforcing roll in accordance with the intersection angle between the work rolls and the intermediate rolls to perform adjustment.

In the third adjustment, the work rolls 1 and 2 are brought into contact with each other, and the positions of the roll chocks of the entire rolling mill are adjusted. At this time, the position of the roll chocks can be adjusted in the case of rotating the work rolls 1 and 2 in the normal direction at the upper left of fig. 17C and in the case of rotating the work rolls 1 and 2 in the reverse direction at the lower side of fig. 17C. This corresponds to the second adjustment in the case of the 4-high rolling mill shown in fig. 4B. In this case, first, the rollers 1 and 2 are rotated (rotated forward), the depressing direction loads on the working side and the driving side are detected for the upper roller system and the lower roller system, respectively, and the reference value 3 is calculated from the load difference between the depressing direction load on the working side and the depressing direction load on the driving side (corresponding to the "third reference value" of the present invention). Next, the rotation directions of the work rolls 1 and 2 are reversed, the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, the load difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated, and the third control target value is calculated based on the deviation of the load difference from the reference value 3. Then, either one of the upper roll system and the lower roll system is set as a reference roll system, and the lower roll system is set as a reference roll system in fig. 17C, and the roll chocks of the rolls of the upper roll system are controlled simultaneously and in the same direction while maintaining the relative positions between the roll chocks of the rolls of the upper roll system, so that the positions of the roll chocks are adjusted to bring the load difference to a value within the allowable range of the third control target value.

Alternatively, the third adjustment may be, for example, to adjust the position of the roller bearing support when stopping the work rollers 1 and 2 at the upper right in fig. 17C and when rotating the work rollers 1 and 2 at the lower side in fig. 17C. This corresponds to the second adjustment in the case of the 4-high rolling mill shown in fig. 8B. In this case, first, in a state where the rotation of the work rolls 1 and 2 is stopped, the depressing direction loads on the working side and the driving side are detected for the upper roll system and the lower roll system, respectively, a reference value 3 is calculated from a load difference between the depressing direction load on the working side and the depressing direction load on the driving side, and a third control target value is set based on the reference value 3. Next, the work rolls 1 and 2 are rotated, and the depressing direction loads on the work side and the driving side are detected for the upper roll system and the lower roll system, respectively, and the difference between the depressing direction load on the work side and the depressing direction load on the driving side is calculated. Then, either one of the upper roll system and the lower roll system is set as a reference roll system, and the lower roll system is set as a reference roll system in fig. 17C, and the roll chocks of the rolls of the upper roll system are controlled simultaneously and in the same direction while maintaining the relative positions between the roll chocks of the rolls of the upper roll system, so that the positions of the roll chocks are adjusted to bring the load difference to a value within the allowable range of the third control target value.

The setting method can be independently determined for each of the first adjustment, the second adjustment, and the third adjustment, and for example, the first adjustment may be performed by rotating the work rolls 1 and 2 forward and backward, and the second adjustment may be performed by stopping and rotating the work rolls 1 and 2. As described above, the present invention can be applied not only to a 4-high rolling mill but also to a 6-high rolling mill. The present invention can be similarly applied to rolling mills other than 4-high rolling mills and 6-high rolling mills, and can be applied to, for example, 8-high rolling mills or 5-high rolling mills. The reference value 1, the first control target value, the reference value 2, the second control target value, the reference value 3, and the third control target value in the 5-roll mill and the 6-roll mill may be obtained by the same methods as in the expressions (1) to (8). The reference value of 4 or more and the control target value of the fourth control target value or more in the 8-roll rolling mill may be obtained by the same methods as those of expressions (1) to (8).

Description of the reference numerals

1: an upper working roll; 2: a lower work roll; 3: an upper reinforcing roller; 4: a lower reinforcing roller; 5 a: an upper work roll chock (work side); 5 b: upper work roll chock (drive side); 6 a: lower work roll chock (work side); 6 b: lower work roll chock (drive side); 7 a: an upper reinforcing roll chock (working side); 7 b: an upper stiffening roller bearing block (drive side); 8 a: a lower stiffening roll chock (working side); 8 b: a lower stiffening roller bearing block (drive side); 9: pressing device for upper operation roller bearing seat; 10: pressing device for bearing seat of lower operation roller; 11: a driving device with a function of detecting the position of the bearing seat of the on-belt operation roller; 12: a driving device with a lower operating roller bearing seat position detection function; 13: the upper reinforcing roller bearing seat pressing device; 14: a driving device with a function of detecting the position of the bearing seat of the belt reinforcing roller; 15: a rolling direction force control device of the roll bearing seat; 16: a roller bearing seat position control device; 21: a driving motor; 22: a drive motor control device; 23: an inter-roller cross control device; 24 a: an enlargement bending device on the entry side; 24 b: an enlarged bending device on the exit side; 25 a: an entrance-side lower enlargement bending device; 25 b: an outlet side lower enlarging bending device; 26: an augmented bending control device; 27: a pressing device; 28 a: an upward pressing direction load detection means (working side); 28 b: an upward pressing direction load detection means (drive side); 29 a: a press-down direction load detection means (working side); 29 b: a press-down direction load detection means (drive side); 30: a housing; 30a, 30 b: pressing down the position of the fulcrum; 32: an upward/downward load difference calculation unit [ subtracter ]; 33: a push-down direction load difference calculation unit [ subtracter ]; 34: a servomotor with a rotation angle detection function; 40: a lower reinforcing roller bearing seat pressing device; 41: an upper intermediate roll; 42: a lower intermediate roll; 43: an upper intermediate roll bearing block; 43 a: an upper intermediate roll chock (work side); 43 b: upper intermediate roll chock (drive side); 44: a lower intermediate roll bearing block; 44 a: a lower intermediate roll chock (working side); 44 b: lower intermediate roll chock (drive side).