阅读说明：本技术 回转式工程机械 (Rotary type construction machine ) 是由 洪水雅俊 于 2018-12-27 设计创作，主要内容包括：本发明的回转式工程机械(100)包括：判定上部回转体(2)的回转是否处于减速状态的回转状态判定部(73)；以及控制马达容量的容量控制部(72)。容量控制部(72)在用于使上部回转体(2)进行回转的操作和用于使附属装置(4)进行动作的操作同时进行的复合操作时,将所述马达容量设为为了所述复合操作而设定的容量,而在回转状态判定部(73)判定为上部回转体(2)的回转处于减速状态的情况下,即使在所述复合操作时,也将所述马达容量设为预先设定的默认容量。(A rotary working machine (100) of the present invention includes: a rotation state determination unit (73) that determines whether or not the rotation of the upper rotation body (2) is in a deceleration state; and a capacity control unit (72) for controlling the capacity of the motor. A capacity control unit (72) sets the motor capacity to a capacity set for a combined operation performed simultaneously with an operation for rotating the upper rotating body (2) and an operation for operating the attachment (4), and sets the motor capacity to a preset default capacity even during the combined operation when a rotation state determination unit (73) determines that the rotation of the upper rotating body (2) is in a deceleration state.)

1. A rotary working machine, comprising:

a substrate;

an upper revolving body rotatably mounted on the base;

an attachment device mounted on the upper slewing body;

a hydraulic pump for discharging working oil;

a swing motor configured from a variable displacement hydraulic motor, and configured to receive a supply of the hydraulic oil discharged from the hydraulic pump and to operate so as to swing the upper swing body;

an actuator that receives a supply of the hydraulic oil discharged from the hydraulic pump and operates to operate the attachment;

a brake circuit that brakes the slewing motor so as to decelerate slewing of the upper slewing body;

a rotation state determination unit that determines whether or not rotation of the upper rotation body is in a deceleration state; and the number of the first and second groups,

a capacity control unit for controlling a motor capacity, which is a capacity of the rotary motor constituting the rotary motor,

the capacity control unit sets the motor capacity to a capacity set for a combined operation of an operation for revolving the upper revolving structure and an operation for operating the attachment at the same time, and sets the motor capacity to a preset default capacity even in the combined operation when the revolving state determination unit determines that the revolving of the upper revolving structure is in a decelerated state.

2. The rotary working machine according to claim 1, wherein:

the slewing motor has a 1 st port and a 2 nd port, rotates in a direction corresponding to one port by receiving a supply of the working oil to the other port of the 1 st port and the 2 nd port, and discharges the working oil from the other port,

the rotary working machine further comprises:

a swing operation device that receives a swing operation for swinging the upper swing body;

a swing operation detection unit that detects a direction of the swing operation applied to the swing operation device;

a rotation speed detector that detects a rotation speed of the upper rotation body;

a working oil pressure detector that detects a pressure of the working oil at the 1 st port and a pressure of the working oil at the 2 nd port; and the number of the first and second groups,

a differential pressure calculation unit that calculates a differential pressure of the slewing motor, which is a difference between the pressure of the hydraulic oil at the 1 st port and the pressure of the hydraulic oil at the 2 nd port, based on the slewing speed detected by the slewing speed detector and the pressure of the hydraulic oil detected by the hydraulic oil pressure detector,

the revolving state determination unit determines whether or not the revolving of the upper revolving unit is in a decelerated state based on the direction of the revolving operation detected by the revolving operation detection unit, the revolving speed detected by the revolving speed detector, and the differential pressure calculated by the differential pressure calculation unit.

3. The rotary working machine according to claim 2, wherein:

the turning state determining section determines a turning state of the vehicle,

determining whether or not the upper slewing body is slewing in the operation direction of the slewing operation based on the direction of the slewing operation detected by the slewing operation detection unit and the slewing speed detected by the slewing speed detector,

when the upper slewing body is slewing in the slewing operation direction and the differential pressure calculated by the differential pressure calculation unit is smaller than a preset threshold value, it is determined that slewing of the upper slewing body is in a decelerated state.

4. The rotary working machine according to claim 2 or 3, wherein:

the displacement control unit controls the motor displacement so as to reduce the displacement of the slewing motor if the pressure of the hydraulic oil at the other port from which the hydraulic oil is discharged is less than a predetermined threshold value and the slewing speed of the upper slewing body is not reduced even when the slewing state determination unit determines that the slewing of the upper slewing body is in a decelerated state.

Technical Field

The present invention relates to a rotary construction machine such as a hydraulic excavator.

Background

A rotary hydraulic working machine generally includes: a lower traveling body; an upper revolving body rotatably mounted on the lower traveling body; an attachment mounted on the upper slewing body; a turning motor that is a hydraulic motor for turning the upper turning body; a hydraulic pump that discharges hydraulic oil to be supplied to the swing motor; and a swing control valve provided between the hydraulic pump and the swing motor. The swing control valve is opened and closed according to an operation of a swing operation lever by an operator, and changes a flow rate of the hydraulic oil supplied to the swing motor among the hydraulic oil discharged from the hydraulic pump.

The hydraulic oil discharged from the hydraulic pump is used not only for the swing motor but also for other hydraulic actuators (e.g., boom cylinder) in many cases. In this case, the other hydraulic actuator is connected to the hydraulic pump via a dedicated control valve different from the swing control valve. That is, the hydraulic pump is used to supply the working oil to the swing motor and the other hydraulic actuators at the same time.

In the case where the swing operation for operating the swing motor and the operation for operating the other hydraulic actuator are performed simultaneously, that is, in the combined operation, the distribution of the flow rate of the hydraulic oil supplied from the hydraulic pump to the swing motor and the other hydraulic actuator is important. For example, patent document 1 discloses a hydraulic device that drives a boom cylinder and a hydraulic motor for swiveling by supplying hydraulic oil from one hydraulic pump to the boom cylinder. The hydraulic device of patent document 1 controls the operation of a hydraulic motor for turning and other actuators by adjusting the turning capacity of the turning motor.

In the above-described composite operation, if the motor capacity of the swing motor is controlled to change, the braking characteristic of the swing motor changes depending on the motor capacity during the deceleration of the swing, and therefore, a stable deceleration operation cannot be realized. In this regard, from the viewpoint of safety, it is desirable that the braking characteristics at the time of deceleration be stable.

Disclosure of Invention

The present invention aims to provide a rotary working machine which can make the motor capacity suitable for the combined operation during the combined operation and can obtain stable braking characteristics during the rotation deceleration of an upper rotary body.

The present invention provides a rotary working machine comprising: a substrate; an upper revolving body rotatably mounted on the base; an attachment device mounted on the upper slewing body; a hydraulic pump for discharging working oil; a swing motor configured from a variable displacement hydraulic motor, and configured to receive a supply of the hydraulic oil discharged from the hydraulic pump and to operate so as to swing the upper swing body; an actuator that receives a supply of the hydraulic oil discharged from the hydraulic pump and operates to operate the attachment; a brake circuit that brakes the slewing motor so as to decelerate slewing of the upper slewing body; a rotation state determination unit that determines whether or not rotation of the upper rotation body is in a deceleration state; and a capacity control unit that controls a motor capacity, which is a capacity of the rotary motor constituting the rotary motor. The capacity control unit sets the motor capacity to a capacity set for a combined operation of an operation for revolving the upper revolving structure and an operation for operating the attachment at the same time, and sets the motor capacity to a preset default capacity even in the combined operation when the revolving state determination unit determines that the revolving of the upper revolving structure is in a decelerated state.

Drawings

Fig. 1 is a view of an example of a rotary working machine according to an embodiment of the present invention.

Fig. 2 is a diagram illustrating a hydraulic circuit mounted on the rotary working machine according to the embodiment.

Fig. 3 is a diagram showing a relationship between a yaw switching pressure and a yaw capacity of a rotary motor in the rotary working machine according to the embodiment.

Fig. 4 is a block diagram showing a functional configuration of the rotary working machine according to the embodiment.

Fig. 5 is a graph showing an example of setting the target motor capacity of the swing motor in the swing type construction machine according to the embodiment.

Fig. 6 is a flowchart of a control example of the rotary working machine according to the embodiment.

Detailed Description

Embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 1 is a side view of a hydraulic excavator as a rotary working machine 100 according to an embodiment of the present invention. The rotary working machine 100 includes: a crawler-type lower traveling body 1 constituting a base body; an upper slewing body 2 which is a slewing body to be carried in a freely slewing manner around a slewing center axis Z perpendicular to a traveling surface thereof; an attachment mounted to the upper slewing body 2; and a hydraulic actuator for operating the attachment.

In this embodiment, the attachment includes: a boom 4 attached to the upper revolving structure so as to be able to move up and down; an arm 5 attached to a distal end of the boom 4; and a bucket 6 attached to the arm 5. The hydraulic actuator includes: a boom cylinder 7 for operating the boom 4; an arm cylinder 8 for operating the arm 5; and a bucket cylinder 9 for operating the bucket 6.

The rotary working machine of the present invention is not limited to the hydraulic excavator described above. The present invention is applicable to various slewing type construction machines (for example, slewing cranes) including a lower traveling structure 1 and an upper slewing body 2 mounted on the lower traveling structure 1 so as to be able to slew. Therefore, the attachment and the hydraulic actuator are appropriately selected according to the type of rotary working machine. The base body is not limited to a movable device such as the lower traveling structure 1, and may be a base for supporting the revolving structure set at a specific location.

Fig. 2 is a diagram illustrating a hydraulic circuit mounted on the rotary working machine 10 according to the embodiment. The hydraulic circuit shows a relevant part of the swing drive of the upper slewing body 2 and the heave drive of the boom 4. The hydraulic circuit includes: a swing motor 10 that is a hydraulic motor for driving the upper swing body 2 to swing; a hydraulic actuator 7 (boom cylinder 7) for raising and lowering the boom 4; a hydraulic pump 30 and a pilot pump 33 connected to an output shaft of the engine 101; and a control valve unit 40.

The turning motor 10 has an output shaft 10c that is rotated by receiving the supply of the working oil, and the output shaft 10c is connected to the upper turning body 2 so as to turn the upper turning body 2 in both the left and right directions. Specifically, the swing motor 10 includes a 1 st port 10a and a 2 nd port 10b, and receives the supply of the hydraulic oil to one of the ports, thereby rotating the output shaft 10c in a direction corresponding to the one port and discharging the hydraulic oil from the other port.

The boom cylinder 7 is provided between the boom 4 and the upper slewing body 2, and causes the boom 4 to move in the ascending direction and the descending direction by extending and contracting, respectively.

The hydraulic pump 30 discharges hydraulic oil for operating the swing motor 10 and the boom cylinder 7. In the present embodiment, the hydraulic pump 30 includes a plurality of hydraulic pumps, specifically, a 1 st hydraulic pump 31 and a 2 nd hydraulic pump 32. However, the hydraulic pump 30 may be constituted by only 1 hydraulic pump.

The 1 st hydraulic pump 31, the 2 nd hydraulic pump 32, and the pilot pump 33 are driven by the engine 101 to discharge hydraulic oil from an oil tank, not shown. Specifically, the 1 st hydraulic pump 31 and the 2 nd hydraulic pump 32 discharge hydraulic oil for operating the boom cylinder 7. The 2 nd hydraulic pump 32 discharges hydraulic oil for operating the swing motor 10. That is, the swing motor 10 that swings the upper swing body 2 and the boom cylinder 7 that operates the boom 4 are connected to the common 2 nd hydraulic pump 32.

The pilot pump 33 discharges pilot oil for supplying pilot pressure for opening and closing the control valves to a plurality of control valves provided in a control valve unit 40 described later.

The control valve unit 40 is provided between the hydraulic pump 30 and the swing motor 10, and performs an operation of changing the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 30 to the swing motor 10. The control valve unit 40 is also provided between the hydraulic pump 30 and the boom cylinder 7, and performs an operation of changing the direction and flow rate of the hydraulic oil supplied from the hydraulic pump 30 to the boom cylinder 7. The specific structure of the control valve unit 40 is not particularly limited as long as it has the above-described function. Next, an example of the control valve unit 40 will be described.

The control valve unit 40 includes, for example, a boom 1-speed control valve, a boom 2-speed control valve, and a swing control valve, which are not shown.

The boom 1-speed control valve is provided between the 1 st hydraulic pump 31 and the boom cylinder 7, and is a control valve that guides the hydraulic oil for driving the boom cylinder 7 from the 1 st hydraulic pump 31 to the boom cylinder 7 and controls the direction and flow rate of the hydraulic oil.

The boom 2-speed control valve is a control valve that is provided between the 2 nd hydraulic pump 32 and the boom cylinder 7, guides the hydraulic oil for acceleration related to the driving of the boom 4 from the 2 nd hydraulic pump 32 to the boom cylinder 7 in addition to the hydraulic oil supplied to the boom cylinder 7 through the boom 1-speed control valve, and controls the direction and flow rate of the hydraulic oil.

The swing control valve is provided between the 2 nd hydraulic pump 32 and the swing motor 10, and guides the hydraulic oil for driving the swing motor 10 from the 2 nd hydraulic pump 32 to any one of the 1 st port 10a and the 2 nd port 10b of the swing motor 10. That is, the swing control valve is a control valve for controlling the direction and flow rate of the hydraulic oil supplied to the swing motor 10.

These control valves are each constituted by a pilot-operated hydraulic switching valve, and a pilot port of each control valve receives supply of a pilot pressure from the pilot pump 33 and opens the valve at a stroke corresponding to the magnitude of the pilot pressure, thereby allowing supply of a flow rate of hydraulic oil corresponding to the stroke to the swing motor 10 or the boom cylinder 7. Thus, the flow rate can be controlled by varying the pilot pressure.

The hydraulic circuit shown in fig. 2 further includes: a swing operation device 12, a right swing line 14, a left swing line 15, a pressure reducing valve circuit 18, a check valve circuit 21, a passage 22, and a makeup flow path 23.

The swing operation device 12 has a swing operation lever 12a and a pilot valve 12 b. The swing lever 12a is an operating member, and when an operator applies a swing command operation to the swing lever 12a, the swing lever 12a rotates in the direction thereof. The pilot valve 12b has an inlet end, not shown, connected to the pilot pump 33 and a pair of outlet ends. The pair of outlet ports are connected to the left and right swing pilot ports, not shown, of the swing control valve of the control valve unit 40 via the right and left swing pilot flow paths, not shown, respectively. The pilot valve 12b is coupled to the swing operation lever 12 a. The pilot valve 12b is opened to allow a pilot pressure corresponding to the magnitude of the swing command applied to the swing control lever 12a to be supplied from the pilot pump 33 to a pilot port corresponding to the direction of the swing command operation, out of the right and left swing pilot ports. For convenience, the swing operating device 12 is illustrated in the position shown in fig. 2, but is actually disposed between the pilot pump 33 and the control valve unit 40 (specifically, the swing control valve).

The pressure reducing valve circuit 18, the check valve circuit 21, the passage 22, and the replenishment passage 23 constitute a brake circuit for braking the swing motor 10. The brake circuit for braking the swing motor 10 is not limited to the configuration shown in fig. 2.

The pressure reducing valve circuit 18 connects the right swing line 14 and the left swing line 15 to each other bypassing the swing motor 10. The relief valve circuit 18 includes a left rotary relief valve 16 and a right rotary relief valve 17. The left and right rotary reducing valves 16 and 17 are configured as follows: the inlet end of the left rotary pressure reducing valve 16 is connected to the right rotary line 14, the inlet end of the right rotary pressure reducing valve 17 is connected to the left rotary line 15, and the outlet ends of the two pressure reducing valves 16, 17 are connected to each other.

The check valve circuit 21 connects the two swing lines 14, 15 to each other at a position closer to the swing motor 10 than the pressure reducing valve circuit 18. The check valve circuit 21 includes a left rotary check valve 19 and a right rotary check valve 20. The left rotary check valve 19 is disposed in a direction in which the hydraulic oil is prevented from flowing in from the right rotary conduit 14, and the right rotary check valve 20 is disposed in a direction in which the hydraulic oil is prevented from flowing in from the left rotary conduit 15.

The passage 22 connects a portion of the relief valve circuit 18 between the left and right rotary relief valves 16 and 17 and a portion of the check valve circuit 21 between the left and right rotary check valves 19 and 20. The makeup flow path 23 connects the passage 22 and the tank 24 to each other so that, when the passage 22 is negative pressure, working oil is allowed to be sucked up from the tank 24 to the passage 22 through the makeup flow path 23 to prevent cavitation. A back pressure valve, not shown, is provided in the supply passage 23.

In this hydraulic circuit, for example, when the swing control lever 12a is returned to the neutral position during the right swing driving and the swing control valve of the control valve unit 40 is returned from the current right swing position to the neutral position, the two swing lines 14 and 15 and the hydraulic pump 30 (specifically, the 2 nd hydraulic pump 32) are disconnected from each other by the swing control valve, but the swing motor 10 continues to rotate in the right swing direction by the inertia of the upper swing body 2. Therefore, the pressure of the left swing pipe 15 on the outlet throttle side rises. When the pressure reaches the set pressure of the right swing relief valve 17, the right swing relief valve 17 opens to allow the hydraulic oil in the left swing pipe 15 to flow into the swing motor 10 through the right swing relief valve 17, the passage 22, the left swing check valve 19, and the right swing pipe 14. Then, the slewing motor 10 that continues to rotate by inertia receives the braking force generated by the action of the pressure reducing valve 17, and the slewing motor 10 is decelerated and stopped. The same applies to deceleration and stop in the case of left turn.

The hydraulic circuit shown in fig. 2 further includes a capacity operation portion 50, a hydraulic pressure supply control portion 60, a capacity pilot flow path 69, a pilot pressure operation valve 68, a control device 70, a swing parking brake 9, and a plurality of sensors.

The plurality of sensors include hydraulic oil pressure detectors 81A and 81B, swing operation detection units 82A and 82B, a swing speed detector 83, and a pump operating pressure detector 84.

The hydraulic pressure detectors 81A and 81B are constituted by a 1 st motor pressure sensor 81A and a 2 nd motor pressure sensor 81B, the 1 st motor pressure sensor 81A generates a 1 st motor pressure detection signal corresponding to the hydraulic pressure of the 1 st port 10a of the swing motor 10, and the 2 nd motor pressure sensor 81B generates a 2 nd motor pressure detection signal corresponding to the hydraulic pressure of the 2 nd port 10B of the swing motor 10. The hydraulic oil pressure detectors 81A and 81B input motor pressure detection signals to the control device 70.

The turning operation detection units 82A and 82B are each configured by a right turning pilot pressure sensor 82A and a left turning pilot pressure sensor 82B, and generate turning pilot pressure detection signals corresponding to the turning pilot pressures input to the pair of turning pilot ports of the turning control valve. The right and left turn pilot pressure sensors 82A and 82B generate pilot pressure detection signals corresponding to the right and left turn pilot pressures of the right and left turn pilot passages 26A and 26B, respectively, and input the pilot pressure detection signals to the control device 70. Therefore, the right swing pilot pressure sensor 82A and the left swing pilot pressure sensor 82B detect that a swing operation command is applied to the swing operation lever 12A of the swing operation device 12, and supply this information to the control device 70.

The rotation speed detector 83 is a sensor capable of detecting the rotation speed and the rotation direction of the upper rotation body 2. As the rotation speed detector 83, for example, an encoder, a resolver, a gyro sensor, or the like capable of detecting the operation of the upper rotation body 2 can be used. The rotation speed detector 83 converts the detected rotation speed and rotation direction of the upper rotation body 2 into an electrical signal (rotation speed detection signal) and inputs the electrical signal to the control device 70.

The pump operating pressure detector 84 generates an operating pressure detection signal corresponding to the operating pressure of the hydraulic pump 30 (the 2 nd hydraulic pump 32), and inputs the signal to the control device 70.

The swing parking brake 90 is a brake device that applies a mechanical stop holding force to the upper swing body 2 to hold the upper swing body 2 in a stopped state when the upper swing body 2 is not driven by the swing motor 10. The swing parking brake 90 is switchable between a braking state in which the stop holding force is applied to the upper swing body 2 and a brake release state in which the upper swing body 2 is released to allow the upper swing body 2 to swing.

The displacement operating unit 50 and the hydraulic pressure supply control unit 60 constitute a displacement control device together with the control device 70. The displacement control device controls the displacement of the swing motor 10, i.e., the displacement, by the hydraulic pressure in accordance with the swing command operation applied to the swing operation lever 12 a.

The displacement operation unit 50 receives the supply of the displacement operation hydraulic pressure under the control of the hydraulic pressure supply control unit 60, and changes the displacement of the hydraulic motor 10. The capacity operating unit 50 includes: a capacity operating cylinder 52 surrounding the piston chamber; and a capacity operating piston 54 charged in the piston chamber of the capacity operating cylinder 52. The displacement operation piston 54 is axially displaceable in the piston chamber and slidable on the inner peripheral surface of the displacement operation cylinder 52. The capacity operation piston 54 is connected to the swing motor 10 so as to change the motor capacity of the swing motor 10 by displacement in the axial direction thereof. For example, when the rotary motor 10 is an axial piston motor, the inclination of the swash plate is changed.

Specifically, the displacement operating piston 54 is coupled to the swing motor 10 via a rod 53 extending from the displacement operating piston 54 through the 1 st hydraulic chamber 55. The capacity operating piston 54 divides the interior of the piston chamber 52 into a 1 st hydraulic chamber 55 and a 2 nd hydraulic chamber 56, and the capacity of the swing motor 10 increases with displacement in the direction in which the volume of the 1 st hydraulic chamber 55 increases (displacement to the right in fig. 1). The axial position of the capacity operating piston 54 depends on the balance between the 1 st capacity operating hydraulic pressure supplied to the 1 st hydraulic chamber 55 and the 2 nd capacity operating hydraulic pressure supplied to the 2 nd hydraulic chamber 56. That is, the displacement operating piston 54 is displaced in a direction (rightward in fig. 1) in which the displacement of the hydraulic motor 10 is increased as the second displacement operating hydraulic pressure is lower than the first displacement operating hydraulic pressure.

The pressure receiving area, which is the area of the capacity operating piston 54 that receives the hydraulic pressure for capacity operation in the first hydraulic chamber 55, is smaller than the pressure receiving area in the second hydraulic chamber 56 by the cross-sectional area of the rod 53. The difference in cross-sectional area allows the displacement operating piston 54 to be held at a position where the volume of the second hydraulic chamber 56 is maximum, that is, a position where the displacement of the hydraulic motor 10 is minimum (leftmost position in fig. 1), when the first displacement operating hydraulic pressure and the second hydraulic pressure operating hydraulic pressure are equal.

The hydraulic pressure supply control unit 60 controls the position of the displacement operating piston 54 by changing the magnitude balance between the first displacement operating hydraulic pressure and the second displacement operating hydraulic pressure, and controls the displacement of the swing motor 10 corresponding to the position.

The supply control unit 60 according to the present embodiment supplies the displacement operation hydraulic pressure to the displacement operation unit 50 and changes the displacement operation hydraulic pressure by using the hydraulic oil from the right swing line 14 or the left swing line 15. The supply control unit 60 includes a hydraulic pressure supply flow path 61, a 1 st branch flow path 61A, a 2 nd branch flow path 61B, a hydraulic pressure supply control valve 62, and a bypass valve 29 shown in fig. 2.

The hydraulic pressure supply passage 61 connects the shuttle valve 29 and the hydraulic pressure supply control valve 62. The hydraulic pressure supply flow path 61 branches at a position between the shuttle valve 29 and the hydraulic pressure supply control valve 62, and connects the shuttle valve 29 and the displacement operating unit 50. The 1 st branch flow path 61A connects the right rotary pipe 14 and the 1 st input portion 29a of the shuttle valve 29. The 2 nd branch flow path 61B connects the left rotary pipe 15 and the 2 nd input portion 29B of the shuttle valve 29.

The shuttle valve 29 communicates the 1 st input portion 29a and the 2 nd input portion 29b on the side where the pressure is high with the hydraulic pressure supply passage 61, and shuts off the side where the pressure is low with the hydraulic pressure supply passage 61. Therefore, the hydraulic oil discharged from the high-pressure side pipe line of the right and left swing lines 14 and 15 is guided to the displacement operation unit 50 through the branch flow path, and the hydraulic pressure for displacement operation is supplied to the 1 st and 2 nd hydraulic chambers 55 and 56 of the displacement operation unit 50.

Specifically, the hydraulic pressure supply passage 61 is branched into a first hydraulic pressure passage 65 connected to the first hydraulic chamber 55 and a second hydraulic pressure passage 66 connected to the second hydraulic chamber 56. The hydraulic pressure supply control valve 62 is provided in the middle of the 2 nd hydraulic pressure flow path 66. The hydraulic pressure supply control valve 62 makes the second displacement operation hydraulic pressure supplied to the second hydraulic chamber 56 through the second hydraulic passage 66 lower than the first displacement operation hydraulic pressure supplied to the first hydraulic chamber 55 through the first hydraulic passage 65 to an extent corresponding to the magnitude of the displacement pilot pressure applied to the hydraulic pressure supply control valve 62.

The hydraulic pressure supply control valve 62 according to the present embodiment is configured by a pilot-operated servo valve, and includes a sleeve 62a, a spool 62b slidably loaded in the sleeve 62a, springs 63 arranged on both sides of the spool 62b in the axial direction, and a pilot port 64. When the pilot port 64 is not supplied with the volume pilot pressure, the spool 62b is held at the fully open position (left position in fig. 2) where the second hydraulic passage 66 is open, with the maximum opening area, by the elastic force of the spring 63. On the other hand, when the pilot port 64 is supplied with the volume pilot pressure, the spool 62b is displaced from the fully open position in the closing direction (leftward in fig. 2) by a stroke corresponding to the magnitude of the volume pilot pressure, and the second volume-operating hydraulic pressure supplied to the second hydraulic chamber 56 is made lower than the first volume-operating hydraulic pressure supplied to the first hydraulic chamber 55.

The displacement pilot flow path 69 guides the hydraulic oil discharged from the pilot pump 33 to the pilot port 64 of the hydraulic pressure supply control valve 62, and thereby supplies a displacement pilot pressure to the pilot port 64.

The pilot pressure operation valve 68 is provided in the middle of the capacity pilot flow path 69, and when receiving an input of a capacity command from the control device 70, opens at an opening corresponding to the magnitude of the capacity command, thereby increasing the capacity pilot pressure supplied to the pilot port 64. The pilot pressure operation valve 68 according to the present embodiment is constituted by a proportional solenoid valve having a solenoid valve 67. The solenoid valve 67 receives supply of an exciting current as the capacity command.

When the solenoid valve 67 is not supplied with the field current (i.e., a capacity command is not input), the pilot pressure operation valve 68 closes, thereby blocking the capacity pilot flow path 69 and preventing the capacity pilot pressure from being supplied to the pilot port 64. On the other hand, when the solenoid valve 67 is supplied with the excitation current (that is, when a capacity command is input), the pilot pressure operation valve 68 opens to open the capacity pilot flow path 69 at an opening degree corresponding to the magnitude of the excitation current, and allows a capacity pilot pressure having a magnitude corresponding to the opening degree to be supplied to the pilot port 64.

Fig. 3 is a diagram showing a relationship between the yaw switching pressure and the yaw capacity of the swing motor 10 in the swing type working machine 100 according to the embodiment. The rotary motor 10 in fig. 3 is a swash plate type axial piston motor in which the motor capacity is changed when the swash plate tilt angle is changed. The rotary motor 10 is not limited to such a motor.

The motor displacement of the swing motor 10 is set to a preset default displacement when the displacement pilot pressure supplied to the pilot port 64 is the pressure Pb. The motor displacement of the swing motor 10 is set to a minimum displacement smaller than the default displacement when the displacement pilot pressure is equal to or lower than the pressure Pa, and is set to a maximum displacement larger than the default displacement when the displacement pilot pressure is equal to or higher than the pressure Pc. Thus, by changing the displacement pilot pressure between the pressure Pa and the pressure Pc, the motor displacement of the swing motor 10 can be set to any value between the minimum displacement and the maximum displacement.

The default capacity is a preset value related to the motor capacity of the swing motor 10. The default capacity is a value preset for decelerating the rotation of the upper slewing body. In other words, the default displacement is a motor displacement used when the rotation of the upper slewing body 2 is in a decelerated state. In the present embodiment, the default capacity is a value smaller than the maximum capacity and larger than the minimum capacity of the motor capacity. The default capacity is a motor capacity that is set in advance so that both a load on the machine due to an excessive torque and a braking torque shortage can be reduced when the braking circuit brakes the swing motor 10, and is appropriately set based on the characteristics of the swing type construction machine 100. Data corresponding to the default capacity is stored in the control device 70.

The control device 70 is constituted by a microcomputer, for example. The controller 70 is configured by a Central processing unit (Central processing unit), a rom (read Only memory) storing various control programs, a ram (random Access memory) used as a work area of the CPU, and the like.

Fig. 4 is a block diagram showing a functional configuration of the rotary working machine 100 according to the embodiment. As shown in fig. 4, the control device 70 functionally includes a differential pressure calculation unit 71, a capacity control unit 72, and a rotation state determination unit 73. The control device 70 is operated by the CPU executing the control program, and functionally realizes the differential pressure calculation unit 71, the capacity control unit 72, and the turning state determination unit 73. The control device 70 executes the control program based on signals input from the hydraulic oil pressure detectors 81A and 81B, the swing operation detection units 82A and 82B, the swing speed detector 83, the pump operating pressure detector 84, and the like, and controls the operation of the swing type construction machine 100 (the operation of the swing motor 10 and the like).

The differential pressure calculation unit 71 can calculate a motor differential pressure Δ P (effective differential pressure Δ P) of the swing motor 10 based on the detection values detected by the hydraulic oil pressure detectors 81A and 81B. The details are as follows.

The working oil pressure at the 1 st port 10a of the slewing motor 10 is a pressure MA, and the working oil pressure at the 2 nd port 10b is a pressure MB. The differential pressure calculation unit 71 calculates the motor differential pressure Δ P based on an equation of MA-MB, when the hydraulic oil is supplied to the 1 st port 10a and discharged from the 2 nd port 10b when the upper slewing body 2 is performing right slewing. The differential pressure calculation unit 71 calculates the motor differential pressure Δ P based on an equation of Δ P — MB-MA when the hydraulic oil is supplied to the 2 nd port 10b and discharged from the 1 st port 10a while the upper slewing body 2 is slewing left.

The turning state determination unit 73 can determine the turning state of the upper turning body 2. The function of the turning state determination section 73 will be described later based on the flowchart shown in fig. 6.

The capacity control unit 72 can control the motor capacity of the swing motor 10. The capacity control unit 72 controls the motor capacity so that the motor capacity of the swing motor 10 reaches the set capacity during the combined operation. Therefore, the swing operation of the upper swing body 2 at the time of the compound operation is in accordance with the preference of the operator. On the other hand, when the revolving state determination unit 73 determines that the revolving of the upper revolving structure 2 is in the deceleration state, the capacity control unit 72 controls the motor capacity so that the motor capacity reaches the default capacity regardless of whether the compound operation is being performed. Accordingly, during the deceleration of the rotation of the upper slewing body 2, the load on the machine due to the excessive torque that may occur when the motor capacity of the slewing motor 10 is set to the preset 1 st set capacity that is larger than the default capacity can be reduced, and the shortage of the braking torque that may occur when the motor capacity is set to the preset 2 nd set capacity that is smaller than the default capacity can be avoided. As a result, at the time of deceleration of the rotation of the upper slewing body 2, a stable braking performance (stopping performance) can be always achieved by the brake circuit. The set capacity is a motor capacity set for the composite operation. The set capacity may be a preset value. The set capacity may be a value (a fluctuation value that fluctuates according to the state of the rotary working machine) that is set according to, for example, the load of the turning operation of the upper turning body 2, the load of the operation of an attachment (for example, the boom 4), the posture of the rotary working machine 100, and the like. Specific examples are as follows.

The displacement control unit 72 can set the motor displacement during the combined operation based on, for example, a target motor displacement set in advance as follows. Fig. 5 is a diagram showing an example of setting the target motor capacity of the swing motor 10 in the swing type construction machine 100 according to the embodiment.

In fig. 5, the vertical axis represents the motor capacity of the swing motor 10, and the horizontal axis represents the swing intensity (cluster adjustment value) of the swing motor 10. In fig. 5, the turning strength on the horizontal axis is a turning strength at which the operator can select turning acceleration of the upper turning body 2 according to his/her preference in the case of a combined operation in which the turning operation of the upper turning body 2 and the raising and lowering operation of the boom 4 are performed simultaneously. The gyration intensity is classified into a plurality of classes (e.g., 10 classes). When an operator operates the swing type construction machine 100, the operator may prefer to prioritize the swing operation of the upper swing body 2, the raising operation of the boom 4, and the like depending on workability, work application, operation skill, and the like. For example, when the operator wants to prioritize the swing operation of the upper swing body 2 at the time of the compound operation, the operator selects a high level from the 10 levels, and when the operator wants to prioritize the raising and lowering operation of the boom 4 at the time of the compound operation, the operator selects a low level from the 10 levels. Specifically, before the operator operates the rotary working machine 100, the operator selects a level of the turning strength from 10 levels using an operation panel, not shown. A signal corresponding to the selected level is input to the control device 70. The control device 70 stores motor capacities corresponding to the turning strengths of the respective levels in advance.

Based on the above-described setting example of the target motor capacity shown in fig. 5, the motor capacity is set and controlled, for example, as follows. That is, the capacity setting unit functionally included in the control device 70 sets, as the set capacity (target motor capacity) at the time of the combined operation, a capacity corresponding to the turning strength selected by the operator among the motor capacities corresponding to the turning strengths of the plurality of levels stored in advance in the control device 70, and the control device 70 stores the set capacity. Then, the capacity control unit 72 controls the motor capacity of the swing motor 10 so as to reach the set capacity set by the capacity setting unit during the combined operation. Specifically, the displacement control unit 72 controls the pilot pressure operation valve 68 and adjusts the displacement pilot pressure supplied to the pilot port 64 so that the motor displacement reaches the set displacement. Therefore, the motor capacity of the swing motor 10 is automatically set to the set capacity in the combined operation in which the swing operation of the upper swing body 2 and the raising and lowering operation of the boom 4 are performed simultaneously.

The "initial setting value" on the vertical axis in fig. 5 is an initial value of the motor capacity that is automatically set when the rotary working machine 100 is started. The "MAX" on the vertical axis in fig. 5 is the motor capacity corresponding to the maximum capacity in fig. 3, and the "Min" on the vertical axis is the motor capacity corresponding to the minimum capacity in fig. 3. Therefore, the motor capacity is set to the initial set value before or without setting the level of the turning strength by the operator. In the present embodiment, the initial set value of the motor capacity in fig. 5 is the same value as the default capacity in fig. 3. But the initial setting value may be a value different from the default capacity.

Fig. 6 is a flowchart of a control example of the rotary working machine 100 according to the embodiment.

The control device 70 reads various detection signals input to the control device 70 (step S1). Specifically, the control device 70 acquires a 1 st motor pressure detection signal and a 2 nd motor pressure detection signal detected by the hydraulic pressure detectors 81A and 81B, a swing pilot pressure detection signal detected by the swing operation detection units 8A and 82B, a swing speed detection signal corresponding to the magnitude, the swing direction, and the like of the swing speed of the upper swing body 2 detected by the swing speed detector 83, and a working pressure detection signal corresponding to the working pressure of the 2 nd hydraulic pump 32 detected by the pump working pressure detector 84. The control device 70 stores data related to these signals.

The control device 70 determines whether the operating pressure of the 2 nd hydraulic pump 32 is less than a preset threshold value a based on the operating pressure detection signal (step S2). When the operating pressure of the 2 nd hydraulic pump 32 is equal to or higher than the threshold value a (no in step S2), the displacement control unit 72 sets the motor displacement of the swing motor 10 to the default displacement (step S11). That is, when the operating pressure of the 2 nd hydraulic pump 32 is a large pressure equal to or higher than the threshold value a, the motor displacement of the swing motor 10 is set to the default displacement, and the swing torque of the swing motor 10 can be prevented from being excessively large. On the other hand, when the operating pressure of the 2 nd hydraulic pump 32 is less than the threshold value a (yes in step S2), the turning state determination unit 73 determines whether or not the turning pilot pressure is equal to or greater than a preset threshold value B based on the turning pilot pressure detection signal (step S3).

When the swing pilot pressure is less than the threshold value B (no in step S3), that is, when the operator does not perform the swing operation, the displacement control unit 72 sets the motor displacement of the swing motor 10 to the default displacement (step S11). On the other hand, when the swing pilot pressure is equal to or higher than the threshold value B (yes in step S3), that is, when the operator performs the swing operation, the differential pressure calculation unit 71 calculates the motor differential pressure Δ P (effective differential pressure Δ P) of the swing motor 10 based on the motor pressure detection signals corresponding to the detection values detected by the hydraulic oil pressure detectors 81A and 81B (step S4). The control device 70 stores the calculation result.

The turning state determination unit 73 determines whether or not the turning speed of the turning motor 10 (the turning speed of the upper turning body 2) exceeds a preset threshold value C and whether or not the turning direction of the turning motor 10 (the turning direction of the upper turning body 2) matches the direction in which the operator turns the turning operation lever 12a, based on a turning speed detection signal corresponding to the magnitude of the turning speed, the turning direction, and the like of the upper turning body 2 detected by the turning speed detector 83 (step S5).

When the magnitude of the rotation speed of the rotation motor 10 is the predetermined threshold value C (no in step S5), that is, when the upper rotation body 2 does not substantially rotate, the displacement control unit 72 sets the motor displacement of the rotation motor 10 to the default displacement (step S11). When the turning direction of the turning motor 10 is the opposite direction to the turning operation direction of the operator (no in step S5), that is, when the operator operates the turning operation lever 12a in the so-called reverse operation lever direction, the displacement control unit 72 sets the motor displacement of the turning motor 10 to the default displacement (step S11).

On the other hand, when the rotation speed of the rotation motor 10 exceeds the threshold C and the rotation direction of the rotation motor 10 matches the rotation operation direction of the operator (yes in step S5), the rotation state determination unit 73 determines whether or not the motor differential pressure Δ P is equal to or greater than a predetermined threshold D (step S6). That is, when the upper revolving unit 2 is revolving and the operator operates the revolving operation lever 12a in the same direction as the revolving direction of the upper revolving unit 2 (when revolving in the operation direction), the revolving state determination unit 73 determines whether or not the motor differential pressure Δ P is equal to or greater than the predetermined threshold value D (step S6).

When the motor differential pressure Δ P is equal to or greater than the threshold value D (yes in step S6), the control device 70 determines whether or not the operation amount applied to the operation lever by the operator to operate the boom cylinder 7 (actuator) is equal to or greater than a preset threshold value E (step S7).

When the operation amount of boom cylinder 7 is equal to or greater than threshold value E (yes in step S7), that is, when a combined operation is performed in which swing operation for operating swing motor 10 and heave operation for operating boom cylinder 7 are performed simultaneously, capacity control unit 72 changes the motor capacity to the set capacity (step S8). Then, control device 70 repeats the above series of processes (steps S1 to S12). The set capacity is not necessarily set based on the motor capacity setting example shown in fig. 5, and may be set by various methods. When the set displacement is set based on, for example, the motor displacement setting example shown in fig. 5, the motor displacement corresponding to the level of the turning strength (see fig. 5) selected in advance by the operator before the operation of the rotary working machine 100 becomes the set displacement.

When the operation amount related to the boom cylinder 7 is smaller than the threshold E (no in step S7), the displacement control unit 72 performs control to set the motor displacement to the default displacement (step S11). That is, when an operation of a swing operation is performed to operate only the swing motor 10 (at the time of a swing-only operation), the capacity control unit 72 performs control to set the motor capacity to the default capacity (step S11). Then, control device 70 repeats the above series of processes (steps S1 to S12).

On the other hand, the condition that the motor differential pressure Δ P is smaller than the threshold value D (no in step S6) may be an index indicating a decrease in the rotation speed of the swing motor 10 and may be an index indicating the possibility of occurrence of cavitation. Therefore, when the motor differential pressure Δ P is smaller than the threshold value D, the turning state determination unit 73 determines whether or not the pressure on the port throttle side (M/O pressure), that is, the hydraulic oil pressure of the port on the hydraulic oil discharge side of the turning motor 10 is smaller than a predetermined threshold value F (step S9).

When the outlet throttle side pressure is less than the threshold value F (yes in step S9), the turning state determination unit 73 determines whether or not the turning speed of the turning motor 10 is equal to or higher than the turning speed of the turning motor 10 detected last time, based on the turning speed detection signal detected by the turning speed detector 83 (step S10). That is, when the brake pressure is not generated in the pipe line (the pipe line 4 or the pipe line 15) connected to the port on the hydraulic oil discharge side of the swing motor 10, the swing state determination unit 73 determines whether or not the swing speed of the swing motor 10 is equal to or higher than the swing speed of the swing motor 10 detected last time, based on the swing speed detection signal corresponding to the magnitude, the swing direction, and the like of the swing speed of the upper swing body 2 detected by the swing speed detector 83 (step S10).

When the rotation speed of the rotation motor 10 is equal to or higher than the rotation speed of the rotation motor 10 detected last time (yes in step S10), that is, when the rotation speed of the upper rotation body 2 is not decreased, the displacement control unit 72 performs control to decrease the motor displacement (step S12). Then, control device 70 repeats the above series of processes (steps S1 to S12).

In the present embodiment, deceleration determination conditions relating to the direction of the turning operation detected by the turning operation detection units 82A and 82B, the turning speed detected by the turning speed detector 83, and the differential pressure Δ P calculated by the differential pressure calculation unit 71 are set in advance. In the present embodiment, when the deceleration determination condition is satisfied and the upper slewing body 2 is in the decelerated state (yes in step S3, yes in step S5, no in step S6), and when the cavitation determination condition is satisfied, such that the hydraulic oil pressure of the port from which the hydraulic oil is discharged is smaller than the preset threshold value F (yes in step S9) and the slewing speed of the upper slewing body 2 is not reduced (yes in step S10), the displacement control unit 72 controls the motor displacement so that the displacement of the slewing motor 10 is reduced (step S12). Thereby, occurrence of cavitation can be suppressed.

When the cavitation determination condition is satisfied, the displacement control unit 72 can perform control for reducing the motor displacement of the swing motor 10 stepwise from the set displacement or the default displacement, for example. Then, while the control device 70 repeats the series of the above-described flow (steps S1 to S12), the displacement control unit 72 can stop the control for reducing the motor displacement of the swing motor 10 when the hydraulic circuit no longer satisfies the cavitation determination condition. When the cavitation determination condition is satisfied, the displacement control unit 72 may reduce the motor displacement of the swing motor 10 from the set displacement or the default displacement to the minimum displacement at a time, for example, instead of reducing the motor displacement in stages as described above.

On the other hand, when the pressure on the outlet throttle side is the threshold value F (no in step S9), the displacement control unit 72 performs control for setting the motor displacement to the default displacement (step S11). That is, when the brake pressure is generated in the pipe (the pipe 4 or the pipe 15) connected to the port on the hydraulic oil discharge side of the swing motor 10 (when the upper swing body 2 is in the decelerating state), the displacement control unit 72 performs control for setting the motor displacement to the default displacement (step S11). Then, control device 70 repeats the above series of processes (steps S1 to S12).

When the pressure on the outlet throttle side is lower than the threshold value F (yes in step S9) and the rotation speed of the swing motor 10 is lower than the rotation speed of the swing motor 10 detected last time (no in step S10), the displacement control unit 72 performs control to set the motor displacement to the default displacement (step S11). That is, when the brake pressure is not generated in the pipe line connected to the port on the hydraulic oil discharge side of the swing motor 10 and the swing speed of the upper swing body 2 is decreasing, the displacement control unit 72 performs control for setting the motor displacement to the default displacement (step S11). Then, control device 70 repeats the above series of processes (steps S1 to S12).

As described above, in the present embodiment, the displacement control unit 72 is configured to be able to control the motor displacement to the set displacement so that the displacement at the time of the combined operation is different from the default displacement, and therefore, the upper revolving structure 2 and the boom 4 can be operated in a state that matches the situation of the combined operation, the preference of the operator, or the like. On the other hand, when the revolving state determination unit 73 determines that the revolving of the upper revolving structure 2 is in the deceleration state, the capacity control unit 72 controls the motor capacity so that the motor capacity reaches the default capacity regardless of whether the compound operation is being performed. Accordingly, during the deceleration of the rotation of the upper slewing body 2, the load on the machine due to the excessive torque generated when the motor capacity of the slewing motor 10 is set to the 1 st capacity which is larger than the default capacity can be reduced, and the shortage of the braking torque generated when the motor capacity is set to the 2 nd capacity which is smaller than the default capacity can be avoided. As a result, at the time of deceleration of the rotation of the upper slewing body 2, a stable braking performance (stopping performance) can be always achieved by the brake circuit.

In the present embodiment, it is possible to determine whether or not the upper slewing body 2 is slewing in the operation direction of the slewing operation, based on the slewing pilot pressure detected by the slewing operation detection portions 82A and 82B and the slewing speed of the upper slewing body 2 detected by the slewing speed detector 83. The effective differential pressure Δ P detected by the hydraulic oil pressure detectors 81A and 81B is smaller than a predetermined threshold value D, which can be an index representing a decrease in the rotation speed of the swing motor 2. Therefore, even when it is determined that the upper slewing body 2 is slewing in the operation direction of the slewing operation, if the condition that the effective differential pressure Δ P is smaller than the threshold value D is satisfied, it can be determined that there is a possibility that the upper slewing body 2 is in the decelerated state.

In the present embodiment, not only the deceleration state of the rotation of the upper slewing body 2 but also the possibility of cavitation can be determined as described above. By controlling the motor capacity based on the determination of cavitation, the occurrence of cavitation can be suppressed. In the rotary working machine 100, the pressure on the outlet throttle side, that is, the hydraulic oil pressure at the port on the hydraulic oil discharge side of the rotary motor 10, is less than the predetermined threshold value F, which can be an index indicating that no brake pressure is generated in the pipe line 14 or the pipe line 5 connected to the port. Therefore, even when it is determined that the upper slewing body 2 is in the decelerating state, if the pressure on the outlet throttle side is smaller than the threshold value F, cavitation may occur in the hydraulic circuit. Specifically, for example, when the rotary working machine 100 is located on an inclined ground, the upper slewing body 2 may be rotated while increasing the slewing speed in the direction in which the gravitational force acts. In this case, since the absorption flow rate of the hydraulic oil supplied to the slewing motor 10 is smaller than the flow rate corresponding to the actual slewing speed of the upper slewing body 2, cavitation may occur in the hydraulic circuit. Therefore, in the present embodiment, in addition to the above-described condition for determining whether or not the upper slewing body 2 is in the decelerated state being satisfied, when the pressure on the outlet throttle side is smaller than the threshold value F and the slewing state determination unit 73 compares the slewing speeds detected a plurality of times by the slewing speed detector 83 and determines that the slewing speed of the upper slewing body 2 is not decreased, the displacement control unit 72 controls the motor displacement so as to decrease the displacement of the slewing motor 10. Thereby, occurrence of cavitation can be suppressed.

The pressure on the outlet throttle side is equal to or higher than the predetermined threshold value F, and may be an index indicating that the brake pressure is generated in the pipe line 14 or 15 to which the port on the hydraulic oil discharge side of the swing motor 10 is connected. Therefore, in the present embodiment, the deceleration determination conditions described above, that is, the deceleration determination conditions relating to the direction of the turning operation detected by the turning operation detection units 82A and 82B, the turning speed detected by the turning speed detector 83, and the differential pressure Δ P of the turning motor calculated by the differential pressure calculation unit 71 are set in advance. Then, in addition to the deceleration determination condition being satisfied, when the pressure on the outlet throttle side is equal to or higher than the threshold value F, the displacement control unit 72 controls the displacement of the swing motor 10 so that the motor displacement reaches the default displacement. This can improve the accuracy of determination of the speed reduction of the upper slewing body 2, and can realize a stable braking performance (stopping performance) by the brake circuit at the time of slewing speed reduction of the upper slewing body 2.

In the rotary working machine 100, the pressure on the outlet throttle side being lower than the threshold value F may be an indicator indicating that no brake pressure is generated in the pipe 14 or the pipe 15 to which the port on the working oil discharge side of the rotary motor 10 is connected, as described above. Also, the pressure on the outlet throttle side being less than the threshold value F may be an index indicating that the brake pressure has an increasing tendency but the brake pressure has not reached the threshold value F. Therefore, in the present embodiment, when the pressure on the outlet throttle side is smaller than the threshold value F and the revolving state determination unit 73 compares the revolving speeds detected a plurality of times by the revolving speed detector 83 and determines that the revolving speed of the upper revolving structure 2 is decreasing, the capacity control unit 72 controls the capacity of the revolving motor 10 so that the motor capacity becomes the default capacity. That is, in the above case, the brake pressure that is the pressure on the outlet throttle side does not reach the threshold value F, but the revolving speed of the upper revolving structure 2 actually decreases, and therefore it is determined that the revolving of the upper revolving structure 2 is in the deceleration state. In this case, the displacement control unit 72 controls the displacement of the swing motor 10 so that the motor displacement reaches the default displacement. This can improve the accuracy of determination of the speed reduction of the upper slewing body 2, and can realize a stable braking performance (stopping performance) by the brake circuit at the time of slewing speed reduction of the upper slewing body 2.

[ modified examples ]

In the above embodiment, as shown in the graph of fig. 5, the case where the operator selects the turning strength according to his/her preference and the motor capacity of the turning motor 10 is set to the selected target motor capacity (set capacity) in the composite operation is exemplified, but the present invention is not limited thereto. The set capacity of the motor capacity of the swing motor 10 at the time of the combined operation may be changed in accordance with, for example, a load of a swing operation of the upper swing body 2, a load of an operation of an attachment (for example, the boom 4), a posture of the swing type construction machine 100, and the like.

In the above-described embodiment, the case where the capacity control unit 72 performs the control of setting the motor capacity to the default capacity when the operation of the swing operation of operating only the swing motor 10 is performed (the case of the swing single operation) is exemplified in step S7 of the flowchart shown in fig. 6, but the present invention is not limited to this. In the swing individual operation, the motor capacity may be set to a preset capacity for the swing individual operation, which is different from the default capacity.

In the above-described embodiment, the rotation state determination unit 73 determines whether or not the rotation speed of the upper rotation body 2 is decreasing by determining whether or not the rotation speed of the rotation motor 10 is equal to or higher than the rotation speed of the rotation motor 10 detected last time in step S10 of the flowchart shown in fig. 6, but the present invention is not limited to this. The turning state determination unit 73 may determine whether or not the turning speed of the upper turning body 2 is decreasing by comparing 3 or more turning speeds detected by the turning speed detector 83.

In the above embodiment, the turning operation detection units 82A and 82B are exemplified by the right turning pilot pressure sensor 82A and the left turning pilot pressure sensor 82B, but the invention is not limited thereto. For example, when an operation signal related to a swing operation of the swing operation device is input to the control device and the direction of the swing operation is detected based on the input operation signal, the swing operation detection unit may be configured as a swing operation detection function provided in the control device.

As described above, there is provided a rotary working machine which, at the time of a compound operation, brings the motor capacity to a capacity suitable for the compound operation and which is capable of obtaining a stable braking characteristic at the time of a rotation deceleration of an upper slewing body.

The present invention provides a rotary working machine comprising: a substrate; an upper revolving body rotatably mounted on the base; an attachment device mounted on the upper slewing body; a hydraulic pump for discharging working oil; a swing motor configured from a variable displacement hydraulic motor, and configured to receive a supply of the hydraulic oil discharged from the hydraulic pump and to operate so as to swing the upper swing body; an actuator that receives a supply of the hydraulic oil discharged from the hydraulic pump and operates to operate the attachment; a brake circuit that brakes the slewing motor so as to decelerate slewing of the upper slewing body; a rotation state determination unit that determines whether or not rotation of the upper rotation body is in a deceleration state; and a capacity control unit that controls a motor capacity, which is a capacity of the rotary motor constituting the rotary motor. The capacity control unit sets the motor capacity to a capacity set for a combined operation of an operation for revolving the upper revolving structure and an operation for operating the attachment at the same time, and sets the motor capacity to a preset default capacity even in the combined operation when the revolving state determination unit determines that the revolving of the upper revolving structure is in a decelerated state.

According to the rotary working machine, the displacement control unit can operate the upper revolving structure and the attachment in a state according to the situation of the combined operation or the preference of the operator by setting the motor displacement to the displacement set for the combined operation at the time of the combined operation, while the braking characteristic can be kept constant by setting the motor displacement to a preset default displacement (by changing the motor displacement back to the default displacement) regardless of whether the combined operation is being performed, when the revolving state determination unit determines that the revolving of the upper revolving structure is in the decelerating state. Therefore, the operator can decelerate the rotation of the upper slewing body with stable braking characteristics, and can safely stop the upper slewing body.

In the rotary working machine, it is preferable that the rotary motor has a 1 st port and a 2 nd port, receives a supply of the hydraulic oil to one of the 1 st port and the 2 nd port, rotates in a direction corresponding to the one port, and discharges the hydraulic oil from the other port, and the rotary working machine further includes: a swing operation device that receives a swing operation for swinging the upper swing body; a swing operation detection unit that detects a direction of the swing operation applied to the swing operation device; a rotation speed detector that detects a rotation speed of the upper rotation body; a working oil pressure detector that detects a pressure of the working oil at the 1 st port and a pressure of the working oil at the 2 nd port; and a differential pressure calculation unit that calculates a differential pressure of the swing motor, which is a difference between the pressure of the hydraulic oil at the 1 st port and the pressure of the hydraulic oil at the 2 nd port, based on the swing speed detected by the swing speed detector and the pressure of the hydraulic oil detected by the hydraulic oil pressure detector, wherein the swing state determination unit determines whether or not the swing of the upper swing body is in a decelerated state, based on the direction of the swing operation detected by the swing operation detection unit, the swing speed detected by the swing speed detector, and the differential pressure calculated by the differential pressure calculation unit.

According to this configuration, since the sufficient deceleration determination condition regarding the direction of the swing operation, the swing speed, and the differential pressure is the determination condition of the deceleration state, the operator can appropriately determine the deceleration state in consideration of the direction of the swing operation, the actual swing speed of the upper swing body, and the differential pressure of the swing motor.

In the slewing type working machine, it is preferable that the slewing state determination unit determines whether or not the upper slewing body is slewing in the operation direction of the slewing operation based on the direction of the slewing operation detected by the slewing operation detection unit and the slewing speed detected by the slewing speed detector, and determines that slewing of the upper slewing body is in a decelerated state when the upper slewing body is slewing in the operation direction of the slewing operation and the differential pressure calculated by the differential pressure calculation unit is smaller than a predetermined threshold value.

According to this configuration, the rotation speed detector can detect the rotation speed of the upper rotation body, that is, the magnitude and the rotation direction of the rotation speed. Therefore, the turning state determination unit can determine whether or not the upper turning body is turning in the turning operation direction based on the direction of the turning operation detected by the turning operation detection unit and the turning speed (magnitude and direction) of the upper turning body detected by the turning speed detector. Further, the fact that the differential pressure (effective differential pressure) of the swing motor calculated by the differential pressure calculation unit is small, that is, the differential pressure is smaller than a predetermined threshold value may be an index indicating a decrease in the rotation speed of the swing motor. Therefore, the revolving state determination unit can determine the decelerated state of the upper revolving structure from the differential pressure when the upper revolving structure is revolving in the operation direction of the revolving operation.

In the slewing type working machine, it is preferable that the displacement control unit controls the motor displacement so as to reduce the displacement of the slewing motor, even when the slewing state determination unit determines that the slewing of the upper slewing body is in a decelerated state, if the pressure of the hydraulic oil at the other port from which the hydraulic oil is discharged is smaller than a predetermined threshold value and the slewing speed of the upper slewing body is not reduced.

According to this configuration, not only the deceleration state of the rotation of the upper slewing body can be determined based on the deceleration determination condition described above, but also the possibility of cavitation can be determined. By controlling the motor capacity based on the determination of the cavitation, the occurrence of the cavitation can be suppressed. Specifically, for example, it is determined whether or not cavitation determination conditions relating to the pressure on the outlet throttle side and the presence or absence of a decrease in the rotation speed are satisfied. In this determination, it is possible to determine whether or not the absorbed flow rate of the hydraulic oil supplied to the slewing motor is less than the flow rate corresponding to the actual slewing speed of the upper slewing body (specifically, the flow rate determined according to the slewing speed and the motor capacity). Therefore, according to this configuration, even when it is determined that the deceleration determination condition is satisfied and the upper slewing body is in the decelerated state, the capacity control unit controls the motor capacity so as to reduce the capacity of the slewing motor when the cavitation determination condition is satisfied, thereby suppressing occurrence of cavitation.