阅读说明：本技术 一种带钢矫直方法及其装置 (Strip steel straightening method and device ) 是由 杨柳 于 2020-11-20 设计创作，主要内容包括：本发明涉及一种带钢矫直方法及其装置,所述方法包括沿带钢运动方向依次对所述带钢施加第一张力、第二张力和第三张力,在所述第一张力和所述第二张力的作用点之间设置延伸辊组,在所述延伸辊组沿所述带钢运动方向设置展平辊组,在所述第二张力和所述第三张力的作用点之间设置均化辊组,所述均化辊组包括相对错位设置的第一均化辊和第二均化辊,所述带钢从中穿过形成连续多个弯曲方向相反的圆弧,从而对所述带钢上的残余应力进行均化。该方法可以消除来料加工造成的浪形影响,消除延伸不均匀产生的横弯和纵弯,并均匀化残余应力,从而获得高强度的带钢,尤其适用于超高强带钢的加工生产。(The invention relates to a strip steel straightening method and a device thereof, wherein the method comprises the steps of sequentially applying a first tension, a second tension and a third tension to a strip steel along the movement direction of the strip steel, arranging an extension roller set between the action points of the first tension and the second tension, arranging a flattening roller set along the movement direction of the strip steel on the extension roller set, arranging a homogenization roller set between the action points of the second tension and the third tension, wherein the homogenization roller set comprises a first homogenization roller and a second homogenization roller which are arranged in a relative staggered manner, and the strip steel passes through the homogenization roller set to form a plurality of continuous circular arcs with opposite bending directions, so that the residual stress on the strip steel is homogenized. The method can eliminate the wave-shaped influence caused by the processing of the incoming materials, eliminate transverse bending and longitudinal bending generated by uneven extension and homogenize the residual stress, thereby obtaining the high-strength strip steel, and being particularly suitable for the processing production of the ultrahigh-strength strip steel.)

1. A strip steel straightening method is characterized by comprising the following steps: applying a first tension, a second tension and a third tension to the strip steel in sequence along the movement direction of the strip steel, wherein the first tension is opposite to the third tension in direction, the second tension is the same as the third tension in direction, the absolute value of the third tension is greater than that of the first tension, and the absolute value of the second tension is greater than that of the first tension;

arranging a set of extension rollers between the points of action of the first tension and the second tension, the set of extension rollers enabling the strip steel to be extended;

arranging a flattening roller set along the movement direction of the strip steel on the extension roller set, wherein the flattening roller set provides the second tension so that the strip steel is flattened;

and a homogenizing roller set is arranged between the action points of the second tension and the third tension, the homogenizing roller set comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered manner, the first homogenizing roller and the second homogenizing roller respectively comprise at least one row of continuous rotatable rollers, and the strip steel passes through the rotatable rollers to form a plurality of continuous circular arcs with opposite bending directions, so that the residual stress on the strip steel is homogenized.

2. The strip straightening method according to claim 1, characterized in that: the second tension is equal to the third tension minus a tension reduction of the leveling roller set, thereby moving the strip in a direction of the second tension.

3. The strip straightening method according to claim 1, characterized in that: the elongation of the strip is dependent on the second tension and the curvature of the strip by the set of draw rolls, the elongation being proportional to the second tension.

4. The strip straightening method according to any one of claims 1 to 3, characterized in that: the extension roller group comprises a first extension roller and a second extension roller which are arranged in a relatively staggered manner, the strip steel passes through the space between the first extension roller and the second extension roller and sequentially contacts the first extension roller and the second extension roller, and the acting forces of the first extension roller and the second extension roller on the strip steel in the direction vertical to the strip steel moving direction are the same in magnitude and opposite in direction;

optionally, the degree of the acting force of the first stretching roller and the second stretching roller on the steel strip in the direction perpendicular to the moving direction of the steel strip is changed by changing the relative staggered depth of the first stretching roller and the second stretching roller, so that the elongation of the steel strip is changed.

5. The strip straightening method according to claim 4, characterized in that: the number of the extension roller sets is 1 or more.

6. The strip straightening method according to any one of claims 1 to 3, characterized in that: the flattening roller group comprises flattening rollers, and the magnitude of the second tension is changed by changing the displacement of the flattening rollers perpendicular to the movement direction of the strip steel.

7. The strip straightening method according to claim 4, characterized in that: the acting force of the first homogenizing roller and the second homogenizing roller on the strip steel in the direction perpendicular to the moving direction of the strip steel is changed by changing the relative staggered depth of the first homogenizing roller and the second homogenizing roller, so that the homogenization degree of the residual stress of the strip steel is changed; preferably, the first homogenizing roller and the second homogenizing roller are relatively staggered to a depth less than the depth of the first stretching roller and the second stretching roller.

8. A strip straightening apparatus for straightening a strip by the strip straightening method according to any one of claims 1 to 7, characterized in that: including the entry stretching device, the extension roller set, the flattening roller set, homogenization roller set and the export stretching device that set gradually along belted steel direction of motion, wherein:

the inlet stretching device provides a first tension opposite to the moving direction of the strip steel;

the extension roller group comprises a first extension roller and a second extension roller which are arranged in a relatively staggered manner, the strip steel passes through the space between the first extension roller and the second extension roller and sequentially contacts the first extension roller and the second extension roller, and the acting forces of the first extension roller and the second extension roller on the strip steel in the direction vertical to the strip steel moving direction are the same in magnitude and opposite in direction;

the flattening roller group comprises flattening rollers, and the flattening rollers generate the second tension on the strip steel;

the homogenizing roller group comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered mode, and the strip steel passes through the space between the first homogenizing roller and the second homogenizing roller to form a plurality of continuous arcs with opposite bending directions, so that residual stress on the strip steel is homogenized;

the outlet stretching device provides a third tension which is the same as the movement direction of the strip steel.

9. The strip straightener of claim 8, wherein: the strip steel straightening device further comprises a roller set pressing-in depth adjusting device, and the roller set pressing-in depth adjusting device adjusts the position of at least one of the extension roller set, the flattening roller set or the homogenizing roller set.

10. The strip straightener of claim 8 or 9, wherein: and a positioning roller is also arranged between the homogenizing roller set and the outlet stretching device, and the positioning roller enables the strip steel to move along the horizontal direction.

Technical Field

The invention relates to the field of cold and hot rolled strip steel production, in particular to a strip steel straightening method and a device thereof.

Background

The strip steel is a narrow and long steel plate produced by various steel rolling enterprises in order to meet the requirements of different industrial departments on industrial production of various types of metal or mechanical products. The strip steel is also called steel strip, the width is within 1300mm, and the length is slightly different according to the size of each roll. The ultra-high strength strip steel is strip steel with yield strength more than 1000Mpa, the strip steel has poor shape of a raw material in the production process, has larger wave shape and high strength, is difficult to be flattened by a conventional pressing method, causes local bending of the strip steel, and has poor flatness.

There are also prior art techniques for improving flatness by applying tension to the strip, however, both machining and strengthening processes to the steel can cause residual stresses. Residual Stress (Residual Stress) refers to the internal Stress of self-equilibrium that remains in the object after the action of external force or uneven temperature field, etc. is eliminated. Such as cold drawing, bending, machining, rolling, shot blasting, casting, forging, welding, and heat treating metals, residual stresses may be caused by non-uniform plastic deformation or transformation. Residual stresses can cause warping or distortion, or even cracking, of the part after improper heat treatment, welding, or machining of the part. Or the surface of the steel plate is cracked after quenching and grinding. The presence of residual stresses sometimes does not immediately manifest itself as a defect, but cracks and breakages occur when the total stress exceeds the strength limit during operation due to the superposition of operating stresses and residual stresses. Due to the uneven distribution of residual stresses, the strip may crack and break when subjected to high strengths, such as 1000 Mpa. Therefore, although the flatness of the ultra-high-strength strip steel can be improved by applying a tensile force, the yield strength is reduced, and the overall mechanical performance of the strip steel cannot be improved.

Therefore, improving the straightness of the cold and hot high-strength steel strips and reducing the residual stress are always production key points and difficulties of strip steel production enterprises, and especially for the ultra-high-strength strip steel with the yield strength of more than 1000Mpa, the quality guarantee by the current process technology is very difficult, so that the method is a bottleneck in the current high-strength steel production field, and the product quality improvement and the industrial structure upgrade are seriously hindered.

Disclosure of Invention

The invention aims to solve the problems of poor flatness and quality grade reduction caused by uneven distribution of residual stress of the conventional strip steel and provides a strip steel straightening method and a device thereof.

In the invention, a first tension, a second tension and a third tension can be set according to the strip steel processing requirement, the first tension is opposite to the third tension, the absolute value of the third tension is larger than the first tension, the second tension is equal to the tension loss of the third minus homogenizing roller set, and the second tension is larger than the first tension, so that the strip steel moves along the direction of the second tension.

Preferably, the first tension and the third tension are both in a horizontal direction, so that the strip steel is dragged and moved from left to right to sequentially pass through the extension roller group, the flattening roller group and the homogenization roller group.

In the invention, the extension roller group extends the strip steel in a dislocation corresponding mode, preferably, the extension roller group comprises a first extension roller and a second extension roller which are arranged in a relative dislocation mode, the strip steel passes through the space between the first extension roller and the second extension roller and sequentially contacts the first extension roller and the second extension roller, and the acting forces of the first extension roller and the second extension roller on the strip steel in the direction vertical to the strip steel moving direction are the same in magnitude and opposite in direction. The relative dislocation means that the rolling surfaces of the first extension roller and the second extension roller are opposite, and the dislocation means that the rolling surfaces of the first extension roller and the second extension roller are not opposite but staggered for a certain distance in the horizontal direction and oppositely penetrate for a certain distance in the vertical direction, so that the acting forces of the first extension roller and the second extension roller on the strip steel in the direction vertical to the movement direction of the strip steel are opposite, and the strip steel is extended after passing through the extension roller set, so that the larger wave-shaped influence caused by the incoming material of the strip steel can be eliminated. The elongation of the strip is dependent on the second tension and the degree of bending of the strip by the pair of stretching rolls, the elongation being proportional to the second tension.

In the invention, because the elongation rates of the upper surface and the lower surface of the strip steel generated by the first extension roller and the second extension roller are often in an asymmetric state along the neutral layer of the strip steel (namely the elongation rates of the upper bending section and the lower bending section formed by the strip steel passing through the extension roller set are not equal), the extension rates of the upper surface and the lower surface are symmetric by supplementing the flattening roller set; if the flattening roller group is not arranged, the asymmetric elongation rate causes the strip steel to have larger longitudinal bending, and the residual stress is not very unbalanced.

In the invention, the homogenizing roller group comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered manner, the first homogenizing roller and the second homogenizing roller respectively comprise at least one row of continuous rotatable rollers, and the strip steel passes through the rotatable rollers to form a plurality of continuous arcs with opposite bending directions, so that the residual stress on the strip steel is homogenized. The relative dislocation refers to the fact that the rolling surfaces of the first homogenizing roller and the second homogenizing roller are opposite, the dislocation refers to the fact that the rolling surfaces of the first homogenizing roller and the second homogenizing roller are not opposite, but staggered by a certain distance in the horizontal direction and oppositely and deeply inserted into a certain distance in the vertical direction, so that the acting force directions of the first homogenizing roller and the second homogenizing roller on the strip steel in the direction vertical to the moving direction of the strip steel are opposite, the strip steel forms a plurality of continuous arcs with opposite bending directions when passing through the rolling surfaces of the two rows of rollers, the residual stress is repeatedly reduced through the forming process of a plurality of arc sections with opposite directions, and finally the residual stress is homogenized. The significance of this is: after the strip steel passes through the flattening roller group, transverse bending and longitudinal bending are easy to occur; through the action of the homogenizing roller group, transverse bending and longitudinal bending generated by uneven extension are further eliminated, and residual stress is homogenized, so that the yield strength is improved, and preferably, the first homogenizing roller and the second homogenizing roller respectively comprise at least 3 rotatable rollers, so that the homogenizing effect is ensured.

In the invention, the relative staggered depth of the roller groups refers to the distance between the contact point of the strip steel and the opposite roller and the central line of the opposite roller. For example, if the offset depth is 0, the movement direction of the strip passing through the opposite rollers is not changed, and if the offset depth is larger, the movement direction of the strip is changed to a larger extent, so that the strip is stretched and the elongation is changed.

The specific scheme is as follows:

a strip steel straightening method comprises the steps of sequentially applying a first tension, a second tension and a third tension to a strip steel along the movement direction of the strip steel, wherein the first tension and the third tension are opposite in direction, the second tension and the third tension are the same in direction, the absolute value of the third tension is larger than that of the first tension, and the absolute value of the second tension is larger than that of the first tension;

arranging a set of extension rollers between the points of action of the first tension and the second tension, the set of extension rollers enabling the strip steel to be extended;

arranging a flattening roller set along the movement direction of the strip steel on the extension roller set, wherein the flattening roller set provides the second tension so that the strip steel is flattened;

and a homogenizing roller set is arranged between the action points of the second tension and the third tension, the homogenizing roller set comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered manner, the first homogenizing roller and the second homogenizing roller respectively comprise at least one row of continuous rotatable rollers, and the strip steel passes through the rotatable rollers to form a plurality of continuous circular arcs with opposite bending directions, so that the residual stress on the strip steel is homogenized.

Further, the second tension is equal to the third tension minus a tension reduction of the leveling roller set, thereby moving the strip in a direction of the second tension.

Further, the elongation of the strip is dependent on the second tension and the curvature of the strip by the set of spreader rolls, the elongation being proportional to the second tension.

Further, the extension roller group comprises a first extension roller and a second extension roller which are arranged in a relatively staggered mode, the strip steel penetrates through the space between the first extension roller and the second extension roller and sequentially contacts the first extension roller and the second extension roller, and the acting forces of the first extension roller and the second extension roller on the strip steel in the direction perpendicular to the strip steel moving direction are the same in magnitude and opposite in direction;

optionally, the degree of the acting force of the first stretching roller and the second stretching roller on the steel strip in the direction perpendicular to the moving direction of the steel strip is changed by changing the relative staggered depth of the first stretching roller and the second stretching roller, so that the elongation of the steel strip is changed.

Further, the number of the extension roller sets is 1 or more, for example 2, 3 or 4, depending on the strip steel processing requirements.

Further, the flattening roller group comprises flattening rollers, and the magnitude of the second tension is changed by changing the displacement of the flattening rollers perpendicular to the moving direction of the strip steel.

Further, the relative staggered depth of the first homogenizing roller and the second homogenizing roller is changed to change the acting force of the first homogenizing roller and the second homogenizing roller on the strip steel in the direction perpendicular to the moving direction of the strip steel, so that the homogenization degree of the residual stress of the strip steel is changed; preferably, the first homogenizing roller and the second homogenizing roller are relatively staggered to a depth less than the depth of the first stretching roller and the second stretching roller.

The invention also provides a strip steel straightening device, which comprises an inlet stretching device, an extension roller set, a flattening roller set, a homogenizing roller set and an outlet stretching device which are sequentially arranged along the movement direction of the strip steel, wherein:

the inlet stretching device provides a first tension opposite to the moving direction of the strip steel;

the extension roller group comprises a first extension roller and a second extension roller which are arranged in a relatively staggered manner, the strip steel passes through the space between the first extension roller and the second extension roller and sequentially contacts the first extension roller and the second extension roller, and the acting forces of the first extension roller and the second extension roller on the strip steel in the direction vertical to the strip steel moving direction are the same in magnitude and opposite in direction;

the flattening roller group comprises flattening rollers, and the flattening rollers generate second tension perpendicular to the movement direction of the strip steel;

the homogenizing roller group comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered mode, and the strip steel passes through the space between the first homogenizing roller and the second homogenizing roller to form a plurality of continuous arcs with opposite bending directions, so that residual stress on the strip steel is homogenized;

the outlet stretching device provides a third tension which is the same as the movement direction of the strip steel.

Further, the strip steel straightening device further comprises a roller set pressing-in depth adjusting device, and the roller set pressing-in depth adjusting device adjusts the position of at least one of the extension roller set, the flattening roller set or the homogenizing roller set.

Furthermore, a positioning roller is arranged between the homogenizing roller set and the outlet stretching device, and the positioning roller enables the strip steel to move along the horizontal direction.

Has the advantages that:

the strip steel straightening method provided by the invention aims at the characteristics of strip steel, and changes the elongation rate of the strip steel through the cooperation of the extension roller set and the tension effect so as to eliminate the wave-shaped influence caused by the processing of incoming materials.

Furthermore, the flattened strip steel is easy to generate transverse bending and longitudinal bending, the transverse bending and the longitudinal bending generated by uneven extension are eliminated through the homogenizing roller set, and the residual stress is homogenized, so that the high-strength strip steel is obtained.

The strip steel straightening method can effectively improve the shape of the strip steel and eliminate the residual stress, has good effect, and is particularly suitable for processing and producing the ultrahigh-strength strip steel.

Drawings

In order to illustrate the technical solution of the present invention more clearly, the drawings will be briefly described below, and it is apparent that the drawings in the following description relate only to some embodiments of the present invention and are not intended to limit the present invention.

FIG. 1 is a schematic view showing the structure of a strip straightener provided in one embodiment 1 of the present invention.

Detailed Description

The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings and the detailed description, but those skilled in the art will understand that the following described embodiments are some, not all, of the embodiments of the present invention, and are only used for illustrating the present invention, and should not be construed as limiting the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention. The examples, in which specific conditions are not specified, were conducted under conventional conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products available commercially.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

Example 1

A strip straightening method comprising: sequentially applying a first tension, a second tension and a third tension to the strip steel along the movement direction of the strip steel, wherein the first tension and the third tension are opposite in direction, the absolute value of the third tension is greater than that of the first tension, and the second tension and the third tension are the same in direction;

arranging a set of extension rollers between the points of action of the first tension and the second tension, the set of extension rollers enabling the strip steel to be extended;

arranging a flattening roller set along the movement direction of the strip steel on the extension roller set, wherein the flattening roller set provides the second tension so that the strip steel is flattened;

and a homogenizing roller set is arranged between the action points of the second tension and the third tension, the homogenizing roller set comprises a first homogenizing roller and a second homogenizing roller which are arranged in a relative staggered manner, the first homogenizing roller and the second homogenizing roller respectively comprise at least one row of continuous rotatable rollers, and the strip steel passes through the rotatable rollers to form a plurality of continuous circular arcs with opposite bending directions, so that the residual stress on the strip steel is homogenized.

Referring to fig. 1, fig. 1 shows a schematic view of the structure of a strip straightener, and the method described above is described in detail with reference to fig. 1.

Strip 0 moves from left to right, and the strip straightener comprises an inlet stretching device (not shown), a 1# extension roller group 1, a 2# extension roller group 2, a flattening roller group 3, a homogenizing roller group 4, a positioning roller 5 and an outlet stretching device (not shown) which are sequentially arranged along the moving direction of the strip, wherein: the inlet stretching device provides a first tension T0 opposite to the moving direction of the strip steel 0, the outlet stretching device provides a third tension T2 which is the same as the moving direction of the strip steel 0, T2 is more than T0, and the strip steel 0 is dragged and moved to sequentially pass through the 1# extension roller group 1, the 2# extension roller group 2, the flattening roller group 3, the homogenizing roller group 4 and the positioning roller 5.

The stretch roller group includes 2 roller groups having the same structure, i.e., a 1# stretch roller group 1 and a 2# stretch roller group 2, and the 1# stretch roller group 1 will be described as an example. 1# extension roller set 1 includes relative dislocation set's first extension roller 11 and second extension roller 12, belted steel 0 follows first extension roller 11 with pass between the second extension roller 12, and contact in proper order first extension roller 11 with second extension roller 12, first extension roller 11 with second extension roller 12 is right belted steel 0 is at the perpendicular to the ascending effort size of belted steel 0 direction of motion is the same, and the opposite direction. And then enters a No. 2 extension roller group 2, and the strip steel 0 is further extended to eliminate a larger wave shape caused by the incoming materials. Because the super-high-strength steel incoming material has poor plate shape and large wave shape and can be eliminated by applying a certain elongation rate, the 1# extension roller group 1 and the 2# extension roller group 2 are matched to complete the removal of the incoming material wave shape.

The 1# extension roller group 1 is also connected with a 1# depth adjusting device 13, such as a compression cylinder or a push rod, and the 1# depth adjusting device 13 changes the relative staggered depth of the first extension roller 11 and the second extension roller 12 so as to change the adjustment of the elongation of the strip steel 0. Similarly, the 2# extension roller group 2 is also connected with the 2# depth adjusting device 21.

The steel strip has high strength, so that the elongation can be generated by larger deformation compared with mild steel, for example, the steel strip has the strength of more than 1000MPa, namely sigma s is more than or equal to 1000MPa, the elongation required by plastic deformation is epsilon which is sigma s/E, E is elastic modulus, the elastic modulus of the steel in a cold state is 210000MPa, therefore, the higher the steel strip strength is, the larger the elongation required by the plastic deformation is, the more the yield strength is, the more the plastic elongation of the steel strip is more than or equal to 0.47 percent, therefore, the invention changes the relative staggered depth of the rollers in the No. 1 extension roller group through the No. 1 depth adjusting device 13 to change the elongation of the steel strip 0.

After passing through the No. 2 extension roller group 2, the strip steel 0 enters the flattening roller group 3, and the flattening roller group 3 generates a second tension T1 which is the same as the movement direction of the strip steel 0 through the flattening rollers to the strip steel 0.

The flattening roller group 3 is also connected with a 3# depth adjusting device 31, and the flattening roller group 3 is pushed to displace through the 3# depth adjusting device 31 so as to change the size of the second tension T1.

After passing through the flattening roller group 3, the strip steel 0 is easy to be subjected to transverse bending and longitudinal bending, and for this reason, the strip steel continues to enter the homogenizing roller group 4, the homogenizing roller group 4 comprises a first homogenizing roller 41 and a second homogenizing roller 42 which are arranged in a relative staggered mode, and the strip steel 0 passes through the space between the first homogenizing roller 41 and the second homogenizing roller 42 to form a plurality of continuous circular arcs with opposite bending directions, so that the residual stress on the strip steel 0 is homogenized. The first and second homogenizing rollers 41 and 42 are connected with a # 4 depth adjusting device 43 and a # 5 depth adjusting device 44, respectively, so that the relative staggered depth of the first and second homogenizing rollers 41 and 42 is adjusted.

The positioning rollers 5 provide acting force to pull the strip steel with the residual stress reduced out of the device, so that the strip steel processing is completed.

When in use, the process setting can be carried out according to the processing requirement of the strip steel 0, and comprises the following steps:

1. setting an outlet tension T2, and calculating an intermediate tension T1 and an inlet tension T0;

2. setting the elongation of the 1# stretching roller group and the 2# stretching roller group, and adjusting the 1# stretching roller press-in depth and the 2# stretching roller press-in depth through the 1# depth adjusting device 13 and the 2# depth adjusting device 21;

3. the depth of penetration of the first homogenizing roller 41 and the second homogenizing roller 42 in the homogenizing roller set 4 is set, and the 4# depth adjusting device 43 and the 5# depth adjusting device 44 are adjusted to the corresponding depth until the transverse bending and longitudinal bending of the strip are eliminated.

The preferred embodiments of the present invention have been described in detail, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. The invention is not described in detail in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the disclosure of the present invention as long as it does not depart from the spirit of the present invention.