JP2000140908A - Rolling mill and rolling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently secure the effects of deflection reduction by offset control or the like even when rolling is in a discontinuous state by decreasing the pressing force of hydraulic cylinders in the case a detected value is larger than the target value and increasing the pressing force of the hydraulic cylinders in the case the detected values are smaller than the target value so that the detected value of the horizontal force is held at a prescribed target value. SOLUTION: With a pressing amplifier 41, driving currents for adjusting the pressure of pressurized oil to be supplied to the hydraulic cylinders 23a, 23b to a desired value are outputted to an electromagnetic proportional reducing valve 39 based on a control signal and detection signal for detecting the horizontal force to the inlet side from horizontal force detectors 40a, 40b provided on the supporting frame 18 on inlet side of a rolling mill. In this manner, so that the horizontal force detected with the horizontal force detectors 40a, 40b is always held at the target value, the pressing force of the hydraulic cylinders 23a, 23b is decreased in the case the detected value is larger than the target value and the pressing force of the hydraulic cylinders 23a, 23b is increased in the case the detected value is smaller than the target value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rolling mill and a rolling method, and more particularly to a rolling mill using a small-diameter work roll suitable for rolling hard and extremely thin materials, and a rolling method using the rolling mill.

[0002]

2. Description of the Related Art Conventionally, in a rolling mill of this type, the smaller the diameter of the work roll, the larger the rolling limit (the thinner the roll), the smaller the diameter of the rolling of hard or ultra-thin materials such as stainless steel. Work rolls have been used.
However, when the diameter of the work roll is reduced, the torsional strength of the work roll itself is reduced, so that the torque required for rolling may not be applied to the work roll in some cases. Thus, when such a small-diameter work roll is used, a roll (an intermediate roll, a reinforcing roll, or the like) that directly or indirectly supports the work roll from above and below is generally used as a drive roll. Here, in such a structure, the work roll
The driving tangential force from the roll in contact with it during rolling,
And the front and rear tensions from the rolled material. These are forces that act on the work rolls in the horizontal direction (hereinafter referred to as horizontal force). However, as the diameter of the work rolls decreases, the bending rigidity of the rolls itself decreases. Roll deflection will occur.

As one of measures for reducing the occurrence of the horizontal deflection, first, a cluster-type multi-high rolling mill such as a so-called Sendimer mill or the like, for example,
A rolling mill or the like has been proposed in which a work roll body is reinforced and supported by a support roll from a horizontal direction to prevent horizontal bending as disclosed in Japanese Patent No. 85509 and Japanese Patent Application Laid-Open No. 60-18206. . However, in each of these rolling mills, since the support rolls divided in the body length direction of the work rolls are used, the marks by the divided support rolls are transferred to the work rolls, and the rolls are further transferred from the work rolls. And the surface properties of the rolled material deteriorate. Other measures for reducing horizontal deflection include, for example, JP-A-63-60006.
There is known a method of offsetting a work roll as described in Japanese Patent Application Laid-Open Publication No. H11-209,837. That is, as shown in FIG. 17, the position of the axis of the work roll is set in the horizontal direction (the direction of the work roll path) from the position of the axis of the roll (the intermediate roll in the figure) in contact with the work roll.
(For example, to the rolled material exit side), the horizontal tangential force Fp of the rolling load P generated by this offset causes the driving tangential force Ft,
It balances against the front tension Tf and the rear tension Tb from the rolled material, suppresses the horizontal force, and reduces the horizontal deflection. However, in an actual rolling mill, these three horizontal forces Ft, Tf, Tb constantly fluctuate, and it is difficult to balance them only by Fp due to work roll offset. Therefore, it is difficult to sufficiently reduce the horizontal deflection, and there is a limit in reducing the diameter of the work roll by this method.

In order to solve the above problem, a rolling mill disclosed in Japanese Patent Laid-Open No. 5-50109 has been proposed as a rolling mill capable of sufficiently reducing horizontal deflection without deteriorating the surface properties of a rolled material. In this rolling mill, first, the work roll positioning support roll provided on one side of the entrance side and the output side and the work roll pressing support roll provided on the other side are outside the maximum plate width. The work roll body portion is supported by the support roll and the two support rolls are movable in the horizontal direction, so that the offset position of the small-diameter work roll is variable during rolling. Further, a support roll for applying a reverse bending force is also provided at an end of the work roll, and can be pressed against the work roll by a hydraulic jack. Thereby, even if a horizontal force that cannot be completely balanced by the offset occurs due to fluctuations during rolling, the reverse bending force is applied to the work roll by the support roll for applying the reverse bending force pressed by the hydraulic jack, whereby the work roll To increase the rigidity. Thereby, the occurrence of the horizontal deflection due to the horizontal force is reduced. Therefore, with this rolling mill, it is possible to roll hard and thin materials having good surface properties with a work roll having a very small diameter. However, in the above rolling mill, since the offset amount δ is determined so that the forces of the support rolls on both sides pressed against the work rolls are equal to each other, there is room for improvement in terms of the responsiveness and accuracy. there were.

Therefore, as a method of controlling a rolling mill capable of improving the responsiveness and accuracy in determining the offset amount by solving the above-mentioned problem, a rolling mill control method described in Japanese Patent Application Laid-Open No. 9-285804 has been proposed. This control method
By determining the offset amount so that the reverse bending forces acting on the entrance side and the exit side of the work roll are equal to each other, the responsiveness and accuracy in determining the offset amount can be further improved.

[0006]

An offset control mechanism for changing an offset position converts a driving force from a driving motor into an axial movement through a worm jack mechanism, thereby providing a control between an input side and an output side. The work roll positioning support roll on one side is moved forward and backward in the path direction. Due to such a configuration, the following speed when the offset amount is changed is relatively slow, and horizontal deflection occurs due to the horizontal force generated before the offset control follows. In the rolling mill described in Japanese Patent Application Laid-Open No. 9-285804, a reverse bending force is applied in a direction that suppresses horizontal deflection detected by a sensor, and offset in a direction that does not require the reverse bending force. It was made. As a result of this control, the work roll offset amount δ is consequently set at a position where the four horizontal forces of load component force Fp, front tension Tf, rear tension Tb, and drive tangential force Ft are balanced by the work roll offset. Controlled.

However, the application of the reverse bending force in the rolling mill suppresses horizontal deflection due to the generated horizontal force, and does not eliminate the horizontal force itself.
That is, even if the deflection is eliminated by the application of the reverse bending force, the horizontal force itself is generated in the work roll until the offset control follows. Therefore, in the case of a discontinuous rolling state or the like, when the magnitude of the horizontal force transiently increases for some reason,
Some inconveniences can occur. Hereinafter, they will be described in detail.

(1) Example of discontinuous rolling state (1-1) Preparation for starting rolling When rolling is started by a rolling mill disclosed in Japanese Patent Application Laid-Open No. 9-285804, work rolls are usually passed. Passing the rolled material away from the line (however, the rolled material is in a stopped state) → approaching the work roll which has been offset in advance, and rolling down the rolled material with a predetermined load P (thereby, the horizontal component force Fp of the rolling load)
Occurs) → the forward tension Tf and the rear tension Tb are applied to the rolled material → the work roll is driven by the rotation of the intermediate roll to start rolling. Here, Japanese Patent Application Laid-Open No. 9-285
No. 804, the offset amount δ
When the determination is made, as in JP-A-5-50109,
It is assumed that four components of the load component Fp, the driving tangential force Ft, the front tension Tf, and the rear tension Tb are acting.
However, as is apparent from the above procedures, since the driving tangential force Ft is not yet applied immediately before the start of rolling (procedure), when rolling is started with the offset amount δ set in advance, For example, a relatively large horizontal force acts forward or backward in the above or the above steps.

(1-2) At the start of rolling As described above, in the rolling mill described in JP-A-9-285804, when the offset amount δ between the intermediate roll and the work roll is determined, In a steady rolling state in which four components of the load component Fp, the driving tangential force Ft, the front tension Tf, and the rear tension Tb are applied, based on a theoretical formula, Ft = Fp + (Tf−Tb) / 2. , Δ = Fp (rw + ri) / P. However, it is inevitable that a difference occurs between the actual phenomenon and the theoretical calculation, and in fact, Ft ≠ Fp + (Tf−Tb) / 2. Therefore, actually, a horizontal force of H = Ft- {Fp + (Tf-Tb) / 2} (Equation A) is suddenly applied to the work rolls simultaneously with the start of rolling.

(1-3) Immediately after the start of rolling and immediately before the end of rolling Immediately after the start of rolling and immediately before the end of rolling, for example, when used as a reversible rolling mill, the beginning and end of the rolled material are at a regular thickness. The rolling state changes largely due to the fact that the rolling speed is gradually increased by acceleration immediately after the start of rolling, and gradually reduced by deceleration immediately before the end of rolling. The horizontal force H represented by the above formula A exists during this time, and changes more rapidly and abruptly than during steady rolling.

(2) Inconvenience when the horizontal force becomes transiently large (2-1) Reduction in life of bearing FIG. 18 shows a main structure of a rolling mill described in Japanese Patent Application Laid-Open No. 9-285804. , A pair of upper and lower work rolls 1 and 2
And an intermediate roll 3 as a pair of upper and lower driving rolls which contact and apply a driving force to these work rolls 1 and 2, respectively.
4, motors 5 and 6 as rotating mechanisms for rotating the intermediate rolls 3 and 4, respectively, and offsets for offsetting the axial positions of the work rolls 1 and 2 from the axial positions of the intermediate rolls 3 and 4 in a substantially horizontal direction. Positioning devices 9 and 10 are provided as mechanisms. The work rolls 1 and 2 have their trunks horizontally supported by the support rolls 12b, 13b, 14b, 15b and the like from the entrance side and the exit side on the outside where the rolled material 11 having the maximum plate width passes. These support rolls 12 to 15 are a pair of support rolls 1 to 15.
7, 18, 19, and 20 are provided at the tips, respectively. The supporting frames 18 and 20 on the entry side are motors (described later).
By the above-mentioned positioning devices 9 and 10 which are moved forward and backward by the drive of, it is possible to move in a substantially horizontal direction during rolling. The outgoing side support frames 17, 19 are moved toward the inlet side so as to follow the movement of the support frames 18, 20 by pressing hydraulic cylinders 23b, 24b or the like to which pressure oil is supplied from a hydraulic source (not shown). Each is pressed at a constant pressure (for example, 1/3 of the maximum pressure of the hydraulic pressure source). By these,
The work rolls 1 and 2 are moved by moving the positioning devices 9 and 10 forward and backward.
Can be changed. In addition, the counter rolls 1 and 2 of the intermediate rolls 3 and 4
On the sides, reinforcing rolls 25 and 26 are provided, respectively.

In the above configuration, (1-1) (1-
2) In any state of (1-3), the horizontal force in the right direction in FIG.
2 That is, this means that the offset of the work rolls 1 and 2 to the left in FIG.
This is a case where the work rolls 1 and 2 try to bend rightward by a horizontal force to the right, but this is prevented by the above-described reverse bending force. However, since the horizontal force itself remains, a horizontal force is applied to the right support rolls 13b, 15b and the like. If the magnitude of this horizontal force becomes extremely large instantaneously, a large load is applied to the bearings such as the support rolls 13b and 15b, and the life thereof is greatly reduced. It is not impossible. (2-2) Separation of work roll and support roll In the above configuration, in the above (1-1) (1-2) (1-
In any state of 3), for some reason,
Contrary to the above, it is assumed that a horizontal force in the left direction in FIG. That is, this is a case where the offset of the work rolls 1 and 2 to the left in FIG. 18 is transiently excessive, and the work rolls 1 and 2 try to bend to the left by horizontal force to the left. This bending is prevented by the reverse bending force as described above, but the horizontal force itself to the left remains. At this time, since the hydraulic cylinders 23b, 24b, etc. are pressing with a constant pressure as described above, if the magnitude of the horizontal force in the leftward direction becomes extremely large instantaneously, the hydraulic cylinders 23b, 24b, The work rolls 1 and 2 may move leftward in the drawing to overcome the pressing force of the support rolls 24b and the like and separate from the support rolls 13b and 15b, so that stable rolling cannot be performed, and a defective shape may occur.

As described above, Japanese Patent Application Laid-Open No. 9-28
In the rolling machine of No. 5804, in a continuous and steady rolling state, it is possible to roll hard and thin material having good surface properties with good responsiveness and accuracy, but in a discontinuous rolling state, It has been difficult to sufficiently secure the original bending reduction effect by offset control, bending control, and the like.

An object of the present invention is to provide a rolling mill and a rolling method capable of sufficiently securing a deflection reduction effect by offset control or the like even in a discontinuous rolling state.

[0015]

(1) In order to achieve the above-mentioned object, the present invention provides a pair of upper and lower work rolls, and a pair of upper and lower drive rolls which respectively contact these work rolls to provide a driving force. The work roll is provided on one of the entrance side and the exit side of the work roll, and the work roll is offset in a substantially horizontal direction from the center position of the drive roll. Offset support means for supporting the work roll from the other side, and a pressure support provided on the other side of the entry side and the exit side of the work roll, for supporting the work roll while pressing the work roll from the other side by the pressing force of a hydraulic cylinder. Means, having a horizontal force detecting means for detecting a horizontal force acting on the offset support means, in a rolling mill to reduce the thickness of the rolled material by the work roll, the detected value by the horizontal force detecting means When the detected value is larger than the target value, the pressing force of the hydraulic cylinder is reduced, and when the detected value is smaller than the target value, the pressing force of the hydraulic cylinder is reduced so as to be kept at a constant target value. A pressure control means for increasing the pressure is provided. In the state where the work rolls are offset, during steady rolling, the horizontal component of the rolling load generated by the offset is balanced by the drive tangential force from the drive rolls to the work rolls and the front and rear tensions from the rolled material and canceled. By doing so, the horizontal force acting on the work roll can be suppressed, and the horizontal deflection of the work roll can be reduced. On the other hand, in the case of a discontinuous rolling state or the like, if the horizontal force transiently increases for some reason, it is difficult to cancel the horizontal force by the rolling load component force due to the offset, and the Horizontal force remains.

For example, when a horizontal force from one side to the other side remains, the pressing and supporting means receives the horizontal force from the work roll. Therefore, when the pressing force of the hydraulic cylinder becomes smaller than the horizontal force, the horizontal force overcomes the pressing force, and the work roll moves to another side. For this reason, the work roll is separated from the offset support means that supports the work roll from one side, and stable rolling cannot be performed. In the present invention, the pressing control means controls the pressing force of the hydraulic cylinder on the pressing support means so that the force acting on the offset supporting means is maintained at a predetermined target value. That is, in the above case, by increasing the pressing force of the hydraulic cylinder from the other side,
The target force is applied to the offset support means on one side by overcoming the horizontal force from the work roll in the opposite direction. As a result, the separation between the offset support means and the work roll as described above can be prevented beforehand, and the original effect of reducing the horizontal deflection due to the offset can be sufficiently ensured.

Conversely, if a horizontal force from the other side to one side remains, the offset support means applies the horizontal force from the work roll and the pressing force from the pressing support means in the same direction. Will receive the resultant force. For this reason, a member provided in the offset support means, for example, a large load is added to the bearing of the support roll that supports both ends of the body portion of the work roll from one side outside the maximum width of the rolled material,
Its life is remarkably reduced or broken, and stable rolling becomes difficult. According to the present invention, in such a case, the force acting on the offset support means on one side is reduced to a target value by reducing the pressing force of the hydraulic cylinder. As a result, the burden on the bearing and the like of the offset support means as described above can be reduced, and the life reduction and breakage can be prevented beforehand, so that the original effect of reducing the horizontal deflection due to the offset can be sufficiently ensured.

(2) In the above (1), preferably,
The offset support means includes a support roll for supporting both ends of the body of the work roll from the one side outside the maximum plate width of the rolled material.

(3) In the above (1), preferably, offset positioning means for positioning a position supported by the offset supporting means is provided.

(4) In the above (3), more preferably, the offset positioning means comprises: a driving motor;
A worm jack mechanism for moving the offset support means in a substantially horizontal direction based on the driving force of the drive motor.

(5) In order to achieve the above object, the present invention provides a pair of upper and lower work rolls, a pair of upper and lower drive rolls which respectively contact these work rolls to provide a driving force, The work roll is provided on one of the side and the output side, and supports the work roll from the one side in a state where the axial position of the work roll is substantially horizontally offset from the axial position of the driving roll. Offset support means, offset positioning means for positioning a position supported by the offset support means, and the other of the input side and the output side of the work roll, which is provided on the other side, and presses the work roll by the pressing force of a hydraulic cylinder. Pressing support means for supporting while pressing from the side, horizontal force detecting means for detecting a horizontal force acting on the offset supporting means, and a horizontal bending A horizontal bending means for applying a force, in a rolling mill for reducing the thickness of the rolled material by the work roll, such that the detection value of the horizontal force detection means is maintained at a predetermined target value, the detection value A pressure control means for reducing the pressing force of the hydraulic cylinder when is larger than the target value, and increasing the pressing force of the hydraulic cylinder when the detected value is smaller than the target value.

(6) In order to further achieve the above object,
The present invention provides a pair of upper and lower work rolls, a pair of upper and lower drive rolls that respectively contact and apply a driving force to these work rolls, and are provided on one of an entrance side and an exit side of the work roll, Offset support means for supporting the work roll from the one side in a state where the axial position of the roll is offset in a substantially horizontal direction from the axial position of the driving roll, and an input side and an output side of the work roll. Press support means provided on the other side, for supporting the work roll while pressing the work roll from the other side by a pressing force of a hydraulic cylinder,
And a horizontal force detecting means for detecting a horizontal force acting on the offset support means, in a rolling method using a rolling mill to reduce the thickness of the rolled material by the work roll, the detection value of the horizontal force detecting means, In order to keep the predetermined target value, the pressing force of the hydraulic cylinder is reduced when the detected value is larger than the target value, and the pressing force of the hydraulic cylinder is reduced when the detected value is smaller than the target value. Press control to increase the pressure is performed.

(7) In the above (6), preferably,
When rolling is started, when the rolling load is increased to a predetermined steady rolling load without rotating the driving roll, the pressing control is started at a first rolling load.

(8) In the above (6), preferably, when the rolling is completed, the rolling load is reduced from a predetermined steady rolling load after the rotation of the driving roll is stopped. The pressing control is terminated after the rolling load of 2.

(9) In the above (6), preferably, when the rolling mill is a reversible rolling mill and the work roll is not driven, the target value is changed according to a pass direction of the rolling mill. To perform the pressing control. In a reversible rolling mill, there are both cases where the direction of the pass is from one side to the other side and cases where the direction of the pass is from the other side to the one side.
In these cases, the offset directions of the work rolls are usually on the other side and one side, respectively. When the work roll is offset to one side (equivalent to the case where the path direction is from the other side to the one side), a transient and large horizontal force is applied from the other side when the work roll is not driven. Although it often occurs in the direction of one side, in this case, in the pressing control, the hydraulic cylinder moves from the other side to the one side by the force of (target value)-(horizontal force to one side). It suffices to push it toward you. On the other hand, if the work roll is offset to the other side (equivalent to the case where the path direction is from one side to the other side),
When the work roll is not driven, a transient and large horizontal force is often generated from one side to the other side.In this case, in the pressing control, the hydraulic cylinder opposes this. (The target value) + (horizontal force on the other side). Therefore, if the target values in the two offset patterns are the same, the pressing force required for the hydraulic cylinder in the latter of the two becomes extremely large, and the members provided in the pressing support means, for example, the maximum sheet width of the rolled material On the outer side, a large load is applied to the bearing of the support roll that supports both ends of the body of the work roll from the other side.

In the present invention, accordingly,
When the work roll is not driven, press control is performed by changing the target value according to the pass direction of the rolling mill.For example, in the above example, when the pass direction changes from one side to the other side, the target value itself is changed. Pressing control is performed with the setting set low. Thus, the pressing force required for the hydraulic cylinder can be reduced, so that the load on the bearings and the like of the support roll can be reduced.

(10) In the above (6), preferably, the rolling mill is provided with a work roll deflection detecting means, and a predetermined light load is applied to the rolled material before starting the rolling. When the detected value of the deflection detecting means is used as the detection reference value, the target value in the pressing control is set to a value equal to the detected value of the horizontal force detecting means when the light load is applied. For example, there is a case where a distance sensor is attached to the offset support means or the pressing support means as the deflection detection means, and the presence or absence of the deflection of the work roll is detected based on a change in the distance from the sensor to the work roll. In this case, the detection distance when a predetermined light load is applied before the start of rolling is used as a reference value, and the presence or absence of deflection of the work roll during rolling is detected based on a difference between the reference value and the detection distance after the start of rolling. Is common. However, strictly speaking, since the offset support means or the pressure support means itself has a slight elastic deformation, even if the work roll is not bent, the offset support means or the pressure support means is larger than when the light load is applied. If horizontal force is acting,
The elastic deformation of the offset support means or the pressing support means increases by the difference in the force. Then, since the detection distance of the sensor changes by this amount, the deflection detecting means may erroneously detect that the work roll is bent. Therefore, the present invention performs the pressing control with the detected value of the horizontal force detecting means at the time of applying a light load as a target value, so that the elasticity of the offset supporting means or the pressing supporting means is maintained while the detected value is the target value. There is no increase in deformation. Thus, it is possible to prevent the occurrence of the deflection detection error during the above-described pressing control.

[0028]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a side view showing a main part structure of the rolling mill according to the present embodiment. FIG. 2 is a top view of a part related to the upper work roll 1 in the structure of FIG. 2 excluding an intermediate roll and a reinforcing roll (described later). Each is shown in FIG.
2 and 3, the rolling mill includes a pair of upper and lower work rolls 1 and 2, and a pair of intermediate rolls 3 and 4 as upper and lower drive rolls that respectively contact the work rolls 1 and 2 to apply a driving force. Motors 5 and 6 for rotating these intermediate rolls 3 and 4 respectively, a servo valve and a cylinder for applying a rolling load (not shown, see FIG. 1 described later),
Upper bending cylinders 7a, 7b, 8a as horizontal bending means for applying a horizontal bending force to the upper and lower work rolls 1, 2;
8b, lower bending cylinders (not shown), and corresponding servo valves (not shown, see FIG. 1 described later), and the axial positions of the work rolls 1 and 2 are changed to the axial positions of the intermediate rolls 3 and 4. Positioning device 9 for offsetting in a substantially horizontal direction from
10 is provided.

The work rolls 1 and 2 are made of a rolled material 1 having a maximum width.
At the outer side where 1 passes, both ends of the body are horizontally moved from the entry side and the exit side by support rolls 12a, 12b, 13a, 13b and 14a (not shown), 14b, 15a (not shown), 15b. Each is supported. These support rolls 12 to 15 are a pair of support rolls 1 to 15.
7, 18, 19, and 20 are provided at the tips, respectively. That is, the support rolls 12a and 12b that support the upper work roll 1 from the output side are supported by the support frame 17 via the corresponding bearings 21a and 21b, and the support rolls 13a and 12b that support the upper work roll 1 from the input side. 13b is supported by the support frame 18 via the corresponding bearings 22a and 22b. Similarly, the support rolls 15 and 14 for supporting the lower work roll 2 from the input side and the output side respectively have corresponding bearings (not shown). ) Are supported by the support frames 19 and 20, respectively. At this time, the support frames 18 and 20 on the entry side can be moved in a substantially horizontal direction during rolling by the positioning devices 9 and 10 which advance and retreat by driving of a motor (described later). In addition, the outgoing side support frame 17, 1
Reference numeral 9 denotes pressing hydraulic cylinders 23a, 23b, 24a (not shown) to which pressure oil is supplied from a hydraulic source (not shown), 2
4b, the support frames 18 and 20 are pressed toward the entrance side so as to follow the movement of the support frames 18 and 20, respectively. Further, upper chocks 16a, 16b and lower chocks 25a, 2 rotatably support the upper and lower work rolls 1, 2, respectively.
5b (not shown, see FIG. 1 described later) is supported slidably in a horizontal direction with respect to a housing fixed to the installation surface. Thus, the offset positions of the work rolls 1 and 2 can be changed by moving the positioning devices 9 and 10 back and forth.

The intermediate rolls 3, 4 are movable in the axial direction by a moving mechanism (not shown). Further, reinforcing rolls 25 and 26 are provided on the side opposite to the work rolls 1 and 2 of the intermediate rolls 3 and 4, respectively.

The upper bending cylinders 7a, 7b and 8a, 8
b is provided so as to be in contact with the upper chocks 16a and 16b, and is supported by the upper work roll 1 by being supplied with pressure oil from a hydraulic source (not shown) via the above-described servo valve to perform an extension operation or a contraction operation. A horizontal bending force with the rolls 12a, 13a or 12b, 13b as fulcrums is applied. A lower bending cylinder (not shown) is also provided on the lower chocks 25a and 25b, and applies a horizontal bending force to the lower work roll 2 with the support rolls 14a and 15a or 14b and 15b as fulcrums.

In the rolling mill having the above basic configuration,
The main parts of this embodiment are offset control (details will be described later),
These are load control (same), bending control (same), rotation control (same), and pressing control (same). In the following description, only control relating to the configuration mainly related to the upper work roll 1 side of the rolling mill will be described as an example, but the same control is performed for the lower work roll 2 side. FIG. 1 shows a configuration of a control device of a rolling mill that performs the above control, which is a main part of the present embodiment, together with a schematic configuration of the rolling mill. FIG. 4 is a block diagram showing functions of the controller shown in FIG. Show. These figures 1
4, the control device 100 of the rolling mill includes a controller 101 and an input unit 102 for manually inputting an instruction by an operator and outputting a corresponding signal to the controller 101.

The controller 101 calculates a predetermined offset position of the work roll 1 which can reduce the horizontal deflection of the work roll 1 during rolling, controls the operation of the positioning device 9 and sets the work roll to an arbitrary offset position. 1, a load control unit that controls the operation of the servo valve 28 and the hydraulic cylinder 29 that performs the above-mentioned load application function and applies an arbitrary rolling load to the reinforcing roll 26. 101b, a bending control unit 101c for controlling the operation of the bending cylinders 7 and 8 and the corresponding servo valves 30 and 31 to apply an arbitrary horizontal bending force to the work roll 1;
Reduces the speed of the motor 5 by controlling the operation of the motor 5 (pinion stand) 2
7, a rotation control unit 101d as rotation control means for rotating the intermediate roll 3 and the pressing cylinder 2
3a, 23b and a pressing control unit 101d for controlling the operation of the corresponding proportional electromagnetic pressure reducing valve 39 to apply a force for pressing the output side support frame 17 toward the input side.

The offset control unit 101a is connected to the input unit 1
02, a signal indicating a rolling condition (described later), a detection signal from a pressure sensor 32a, 32b for detecting the pressure of pressure oil supplied to the upper bending cylinders 7a, 7b, and a movement position of the support frame 18. Movement detection means, for example, a detection signal from a pulse generator 33 that detects the rotation of a drive motor 9a that is a drive source of the positioning device 9 is input, and a control signal that controls the rotation operation of the drive motor 9a is output. Has become. The drive motor 9a is
It rotates according to this control signal, and this rotation is performed by the gear mechanism 9b.
Through the worm jack mechanism 9c, whereby the position of the support frame 18 moves forward and backward in a substantially horizontal direction.

The load control unit 101b receives a signal indicating the rolling condition (described later) from the input means 102 and the hydraulic cylinder 29
And a feedback signal from a pressure sensor 35 that detects the pressure of the pressure oil supplied to the hydraulic cylinder 29. Based on these two signals, the pressure in the hydraulic cylinder 29 is adjusted to a desired value by the servo valve 28 for pressure reduction. A control signal (drive current) is output. At this time, the upper reinforcing roll 25
, A pressure sensor (for example, a load cell) may be provided, and the pressure detected from this load cell may be controlled to a desired value.

The bending control unit 101c detects a signal representing a target deflection value (described later) from the input means 102 and the deflection of the work roll 1 from the deflection detector 36 provided on the support frame 18 on the entry side of the rolling mill. A detection signal to be detected is input, and a control signal is output to bending servo amplifiers 37 and 38 that output drive current to servo valves 30 and 31, respectively. And servo amplifier 3
7, 38 based on these control signals and the deflection detection signal from the deflection detector 36, the hydraulic cylinders 7a, 7b
And a drive current for adjusting the pressure of the pressure oil supplied to the inside of each of the servo valves 30 and 31 to a desired value. The deflection detector 36 is a known distance sensor that measures the distance from the work roll 1, for example.

The rotation control unit 101d receives a signal representing a rolling condition (described later) from the input means 102 and outputs a control signal to the motor 5 for rotating the intermediate rolls 3 and 4. The motor 5 rotates at a predetermined speed according to the control signal.

The pressing control section 101e receives a signal representing a target value (described later) from the input means 102 and outputs a control signal to the pressing amplifier 41 which outputs a driving current to the proportional electromagnetic pressure reducing valve 39. ing. And the amplifier 41
The control signal and the support frame 18 on the entry side of the rolling mill
Horizontal force detectors (load cells) 40a, 40
b, the drive current for adjusting the pressure of the hydraulic oil supplied to the hydraulic cylinders 23a and 23b to a desired value based on the detection signal for detecting the horizontal force from the input side to the input side.
9 to output the horizontal force detectors 40a, 40b
If the detected value is greater than the target value, the hydraulic cylinders 23a, 23
When the pressing force of the hydraulic cylinders 23a and 23b is decreased and the detected value is smaller than the target value, the pressing force of the hydraulic cylinders 23a and 23b is increased.

The controller 101 includes a control system for this type of rolling mill system in addition to the offset control unit 101a, the load control unit 101b, the bending control unit 101c, the rotation control unit 101d, and the pressing control unit 101e. A well-known function of controlling the rotation of a roll for feeding and winding the rolled material and controlling other devices in the rolling mill system may be provided.

In the above, the entrance side (the right side in FIGS. 1 to 3) constitutes one of the entrance side and the exit side of the work roll, and the exit side (the left side in FIGS. 1 to 3) is the work side. It constitutes the other side of the entrance side and the exit side of the roll. Further, the entry-side support frames 18, 20 and the support rolls 13a, 13b, 15a,
15b is provided on one side, and constitutes offset support means for supporting the work roll from one side in a state in which the axial position of the work roll is substantially horizontally offset from the axial position of the driving roll, The positioning devices 9 and 10 constitute offset positioning means for positioning the position supported by the offset support means. Also, the outgoing side support frame 17,
19 and support rolls 12a, 12b, 14a, 14b
Are provided on the other side of the entry side and the exit side of the work roll, and constitute pressing support means for supporting the work roll while pressing it from the other side by the pressing force of the hydraulic cylinders 23a, 23b, 24a, 24b. .

Next, the operation of this embodiment will be described step by step with reference to FIG. 5, which is an operation flow from the start of rolling to the end of rolling.

(A) Start of Rolling The control procedure of the controller 101 at the start of rolling will be described with reference to the flowchart of FIG. (A-1) Preparation for Rolling Start In FIG. 6, when rolling is started, first, in step S200.
Then, various conditions instructed and input by the operator through the input means 102, namely, the radius rwo of the work roll 1 before deformation, the radius ri of the intermediate roll 3, the reduction amount Δh for the rolled material 11,
Strip width B of rolled material 11, forward and backward tension T applied to rolled material
f, Tb, a predetermined rolling load P (for example, P = 300 tons to 5
00 tons), Poisson's ratio ν and Young's modulus E of the work roll 1, a target value of the deflection (eg, zero) for reducing the horizontal deflection of the work roll 1, and a target value of the pressure difference between the bending cylinders 7 a and 7 b (described later). , And horizontal force detectors 40a, 40
b, the target value of the detected horizontal force (in this embodiment, FIG.
(E) As shown in (e), when the roll is not driven, E ton, and when driven, D ton same as horizontal deflection zero clear.
Is input.

Thereafter, the procedure proceeds to step S201, where the offset control unit 101a predicts that the horizontal deflection generated in the work roll 1 during rolling will be the target deflection value (entered in step S200). Calculate the initial offset amount δ. This calculation is performed based on the following concept and calculation procedure. That is, as shown in FIG. 7, the initial offset amount δ is, during rolling, the horizontal component Fp of the rolling load P due to the offset of the work roll 1 and the driving tangential force Ft acting on the work roll 1 from the intermediate roll 3. From the rolled material 11 to the front of the work roll 1
The forward tension Tf and the rear tension Tb acting on the rear respectively are set to the amounts expected to be balanced. That is,
What is necessary is just to set to the offset position which satisfies the following formula 1.

Ft = Fp + Fs (Equation 1) Here, Fs is obtained by viewing the front / rear tensions Tf and Tb as horizontal forces acting on one work roll, and is expressed by the following equation 2. Fs = (Tf−Tb) / 2 (Equation 2) In this case, strictly speaking, the rolling load P is
9 → Chock of lower reinforcing roll 26 → Lower reinforcing roll 26 →
Lower intermediate roll 4 → lower work roll 2 → rolled material 11 → upper work roll 1 → upper intermediate roll 3 → upper reinforcement roll 25 → housing is transmitted, but upper work roll 1 and upper middle roll 3
When viewed from the relationship between the upper work roll 1 and the work work roll 1, as shown in FIG.

Here, the load component Fp is expressed by the following equation 3 using the rolling load P, the working roll radius rwo, and the intermediate roll radius ri. Fp = P · δ / (rwo + ri) (Equation 3) Accordingly, by substituting these Equations 2 and 3 into Equation 1, the initial offset amount δ is expressed by the following Equation 4.

Δ = (rwo + ri) ｛Ft− (Tf−Tb) / 2｝ / P (Equation 4) Here, the driving tangential force Ft in Equation 4 needs to be predicted from various conditions required for operation. . put it here,
According to a well-known simple formula of the rolling theory (for example, “Theory and Practice of Sheet Rolling”, edited by The Iron and Steel Institute of Japan, P21), the rolling torque T is determined by the reduction amount Δh, the sheet width B, the Poisson's ratio ν, and the Young's Using the ratio E, it is expressed by the following equation 5. _{T = a G · P-rwo} · (Tf-Tb) / 2 ... ( Equation 5) However, a _G (= "torque _{arm") = λ G · L · (} rwo /
rw) L (= “projected contact arc length”) = (Δh · rw) ^1/2 rw = rwo {1+ (Co · P) / (Δh · B)} Co = 16 (1−ν ² ) / πE The driving tangential force Ft is calculated based on the following equation (6).
Is calculated. _{Ft = T / rwo = a G} · P / rwo- (Tf-Tb) / 2 ... ( Equation 6) Accordingly, by substituting the equation 6 into equation 4 described above, the initial offset δ determined by Equation 7 below be able to. δ = (rwo + ri) {λ _G (Δh · r w) ^1/2 / r w− (Tf−Tb) / P} (Equation 7) In the expression 7, other than λ _G (= “torque arm coefficient”) Since all numerical values are determined by the rolling conditions, Equation 7 can be solved algebraically easily if λ _G is appropriately determined.
It is known that this λ _G is generally about 0.5 in cold rolling, and it has been confirmed by analysis of actual rolling data by the present inventors that λ _G = 0.4 to 0.5. We were able to. Further, the inventors of the present application calculate the driving tangential force from the actual torque measured during rolling and substitute the calculated driving tangential force into Expression 4 and Expression 7 using λ _G = 0.4 to 0.5. By comparing with the offset amount, it was confirmed that Expression 7 had sufficient accuracy for practical use.

Based on the concept described above, the procedure in step S20
In step 1, the initial offset amount δ is calculated using equation (7).

Calculating the initial offset amount δ by the above method has the following merits.
That is, as a conventional method for predicting the rolling torque, a long-known Brand & Ford formula (for example, “Rolling Theory and Its Application” edited by the Iron and Steel Institute of Japan, pages 44 to 4)
Although there is a method using 5), this formula needs to use the friction coefficient μ as an initial condition, and it is generally difficult to predict the friction coefficient μ. In addition, this Brand & Ford
Is usually solved simultaneously with the equation of the elastic flatness of the roll, so it is necessary to perform a convergence calculation.In some cases, the solution does not converge, and the calculation becomes complicated. It is not appropriate to use for control. On the other hand, in the above method performed by the rolling mill of the present embodiment, by using Equation 7 which can be easily solved algebraically,
A convergence calculation like the d & Ford formula is unnecessary and a solution is always found. That is, the initial offset amount δ can be quickly and reliably obtained by practical calculation.

When the above-described procedure S201 is completed, the process proceeds to step S202, where the offset control unit 101a outputs a drive signal for moving the work roll 1 to the position of the initial offset amount δ to the drive motor 9a. This allows
The rotation of the drive motor 9a is transmitted to the worm jack mechanism 9c via the gear mechanism 9b, and the work roll 1 moves to the position of the offset amount δ. By moving the offset position to the initial offset amount δ accurately before the start of the rolling, the horizontal bending cylinders 7 and 8 apply a long-time bending force as in the case where the offset position is largely moved after the start of the rolling. This eliminates the necessity, so that the problem of deterioration in fatigue strength does not occur. In addition, since the capacity of the horizontal bending cylinders 7 and 8 can be given a margin, it is possible to ensure the stability of control against disturbances such as a sudden change in thickness and tension during rolling. At this point, since the rolled material 11 has already been passed below the work roll 1, the work roll 1 is moved in this movement by the rolled material 11 and the support roll 21 a,
There is a case where the robot moves while contacting 21b (or 22a, 22b). Therefore, preferably, the load control unit 101
b, the upper and lower work rolls 1 and 2
It is desirable that the work roll 1 be controlled so as not to contact with the surface and to surely prevent the work roll 1 from being damaged.

Thereafter, the process proceeds to step S203, where the load control unit 101b outputs a current signal for applying a light load such that horizontal deflection of the work roll 1 hardly occurs to the servo valve 38 for pressure reduction. Thereby, the servo valve 2
8 raises the pressure in the hydraulic cylinder 29, raises the chock rotatably supporting the lower reinforcing roll 26, and applies a light load A ton (for example, A ≒ several tens tons, see FIG. 5 (a)) to the rolled material 11. Give. At this time, the horizontal force detector 40
At a and 40b, the horizontal force of D ton (see FIG. 5 (d) described later) is detected, and this value becomes the target value at the time of non-driving in the pressing control as described above. Then, the process proceeds to step S204, in which the bending control unit 101c inputs a detection signal from the deflection detector 36 in the light load application state, and further, in step S205, the value of the deflection amount (a certain minute value) at that time.
Is the control target value. The reason for setting such a control target value is that the work roll 1 is tightly adhered to the upper intermediate roll 3, the support rolls 12a, 12b, 13a, 13b, and the rolled material 11 without looseness in four directions, up, down, left, and right. This is to ensure the support (see FIG. 2) and thereby eliminate the detection error of the deflection detector 36 which may occur when there is a gap between the support rolls 13a and 13b and the work roll 1.

When step S205 is completed, step S2
In step 06, the bending control unit 101c starts horizontal bending control for the work roll 1. That is, the bending control unit 1
01c is a control start signal for starting horizontal bending control for controlling the deflection so as to approach the target value based on the control target value input in step S200, and sends the control start signal to the bending servo amplifier 3;
7 and 38. Thereby, the servo amplifier 37,
38 starts control as shown in FIG. That is, in FIG. 8, first, in step S300, a detection signal from the deflection detector 36 is input, and in step S301, a deviation between the detected deflection amount and the control target value is obtained. Then, the process proceeds to step S302 where the current signal proportional to the deviation is supplied to the servo valve 3
0, 31 to supply hydraulic oil to the corresponding bending cylinders 7a, 7b or 8a, 8b, and apply a horizontal bending force to the work roll 1 via the chocks 16a, 16b so as to reduce deflection. give. When the procedure 302 is completed, the procedure returns to the procedure 300, and the same procedure is repeated. This control is performed by the horizontal deflection detector 36 as shown in FIG.
Is configured as a closed loop that feeds back the analog signal to the servo valves 30 and 31 by the hardware circuits in the servo amplifiers 37 and 38, thereby enabling high-speed control.
In step S205, the deflection value in the control target value is forcibly set to zero (that is, zero clear), and the deflection detector 36 detects the value of the horizontal deflection of the work roll 1 based on this, and in step S206, the deflection is zero. May be controlled so as to approach.

Upon completion of step S206, step S206 is performed immediately (at substantially the same time as step S206).
In step 207, the load control unit 101b outputs a current signal for applying a predetermined rolling load P to the servo valve 28 for rolling down. As a result, as in step S203, the servo valve 28 raises the pressure in the hydraulic cylinder 29 to lift the choke of the lower reinforcing roll 26, and the predetermined rolling load (300 tons to 50 tons).
0 ton) P is applied to the rolled material 11. As a result, the horizontal component Fp of the rolling load P acts on the work roll 1, but since the upper intermediate roll 3 is not rotating and the drive tangential force Ft does not act on the work roll 1, the offset amount δ
In the setting balance, the horizontal force toward the output side of the pass line remains and acts on the work roll 1 to cause horizontal deflection to the output side. However, at this time, since the horizontal bending force has already been applied to the work roll 1 in step S206,
The horizontal deflection can be forcibly corrected by the bending force, and the horizontal deflection can be sufficiently reduced. This state is shown in FIG.
Shown in

However, the application of the reverse bending force in step S206 suppresses the horizontal deflection due to the horizontal force in the leftward direction in FIG. 7 (from the entry side to the exit side) caused by the addition of the load component Fp. Yes, it does not eliminate the horizontal force itself. Therefore, even if the deflection is eliminated by the application of the reverse bending force, the horizontal force itself is generated in the work roll 1, and as shown in FIG. 5D, the horizontal force detectors 40a, 40b The detected value at decreases. Therefore, when the hydraulic cylinders 23a and 23b press at a constant pressure as in the related art, when the magnitude of the horizontal force is extremely large, the work roll 1 is released by overcoming the pressing force of the hydraulic cylinders 23a and 23b. It moves to the side and separates from the support rolls 13a and 13b, so that stable rolling cannot be performed and shape defects may occur.

Therefore, in the present embodiment, in step S208 after step S207, the pressing control of the hydraulic cylinders 23a and 23b is started by the pressing control unit 101e. That is, the pressing control unit 101e generates a control start signal for starting pressing control for controlling the horizontal force detected by the horizontal force detectors 40a and 40b to be the target value based on the target value input in step S200. Output to the pressing amplifier 41.
Based on this, the amplifier 41 starts control as shown in FIG. That is, in FIG.
0, the detection signals from the horizontal force detectors 40a, 40b are input, and in step S501, the horizontal force detectors 40a, 40b
The sum of the 0b detection signals is obtained. Then, in step S502,
The deviation between the sum of the detected horizontal forces and the target value is obtained. Then, proceeding to step S503, a current signal proportional to the deviation is output to the proportional electromagnetic pressure reducing valve 39, whereby pressure oil is supplied to the corresponding pressing cylinders 23a and 23b, and the support frame 17, the support rolls 12a and 12b, A horizontal force from the exit side to the entrance side is applied to the support frame 18 via the roll 1 and the support rolls 13a and 13b. When the procedure 503 is completed, the procedure returns to the procedure 500, and the same procedure is repeated. This control is performed by the horizontal force detector 40 as shown in FIG.
Since it is configured as a closed loop in which the analog signals a and 40b are fed back to the proportional electromagnetic pressure reducing valve 39 by a hardware circuit in the amplifier 41, high-speed control is possible.

As described above, by controlling the pressing force of the hydraulic cylinders 23a and 23b by the pressing control unit 101e so that the force acting on the support frame 18 is maintained at a predetermined target value, as described above. In response to the increase in the horizontal force from the work roll 1 to the exit side due to the increase in the rolling load, FIG.
As shown in (1), the pressing force of the hydraulic cylinders 23a and 23b is increased. As a result, the target force is applied to the support frame 18 by overcoming the horizontal force in the opposite direction from the work roll 1 to the exit side, as shown in FIG.
The decrease in the detection value of the horizontal force detector 40 is stopped at the non-driving target value E ton (described later) and can be maintained at this E ton. Thereby, the support rolls 13a,
The separation between the work roll 13b and the work roll 1 can be prevented beforehand, and the original horizontal deflection reduction effect by the bending control described above and the offset control described later can be sufficiently ensured.

However, as shown in FIG. 5 (a), when the rolling load is increased from the light load to the predetermined steady rolling load in the step S207, the predetermined first rolling load (step S208) is performed. In this embodiment, B tons, for example, B ≒
(A + 10).

(A-2) At the start of rolling When the rolling in steps S207 and S208 progresses and reaches a predetermined rolling load P (P = 300 to 500 tons), the process proceeds to step S209, where the rotation control unit 101d Then, a drive signal to start driving the intermediate roll 3 and start rolling is output to the motor 5. As a result, the motor 5 starts rotating, the intermediate roll 3 starts rotating, the driving of the work roll 1 is started, and the rolling of the rolled material 11 is started. This allows
The driving tangential force Ft described with reference to FIG. 7 acts. Here, when determining the offset amount δ between the intermediate roll and the work roll in step S201, the load component Fp, the driving tangential force F
t, Ft = Fp + (Tf−Tb) / 2 in a steady rolling state in which the four forces t, front tension Tf, and rear tension Tb are acting. 1 and Equation 2). Therefore, theoretically, at the start of driving of the work roll, the above four forces are balanced, and no horizontal force should act on the work roll 1. However, it is inevitable that a difference occurs between the actual phenomenon and the theoretical calculation, and in fact, Ft ≠ Fp + (Tf−Tb) / 2. Therefore, in practice, a horizontal force of H = Ft- {Fp + (Tf-Tb) / 2} is suddenly applied to the work roll simultaneously with the start of rolling.

Therefore, in order to cancel the horizontal force, the procedure proceeds to step S210 after step S209, and the offset control unit 101a starts offset control for controlling the offset amount of the work roll 1. The details are shown in FIG. That is, in FIG. 11, the offset control unit 1
First, in step S400, a detection signal from the pressure sensor 32a for detecting the pressure of the pressure oil to the bending cylinder 7a is input. In step S401, the pressure sensor 32b for detecting the pressure of the pressure oil to the bending cylinder 7b. The detection signal from is input. Thereafter, in step S402, it is determined whether or not the difference between the two detected pressures is equal to or less than the target value of the pressure difference input in step S200. If the difference is equal to or less than the target value, it is determined that the horizontal deflection to be bent and corrected is not so much generated in the work roll 1, and the process returns to the step S400, and the same procedure is repeated. If the target value is exceeded, it is determined that a relatively large horizontal deflection has occurred and the procedure S
In 403, a drive signal for reducing the horizontal deflection below the target value is output to the drive motor 9a.
The rotation of the drive motor 9a is transmitted to the worm jack mechanism 9c via the gear mechanism 9b, and the work roll 1 reduces the horizontal deflection (that is, the load component Fp, the drive tangential force Ft,
(The front and rear tensions Tf and Tb are balanced.) When the procedure 403 is completed, the procedure returns to the procedure 400, and the same procedure is repeated. Due to such control, even if there is an error between the calculated value of the initial offset amount δ calculated in step S201 and the offset amount at which Fp, Ft, Tf, and Tb are completely balanced, the work roll 1 can be moved. And move to the balance position of the four horizontal forces as shown in FIG. 12 within a relatively short time.

However, even though it is a relatively short time, the positioning device 9 controls the rotation of the drive motor 9a by the gear mechanism 9b.
Is transmitted to the worm jack mechanism 9c through the worm jack mechanism 9c to move the work roll 1, and therefore, the response to a transient horizontal force is not always sufficient.
The horizontal force H = Ft− {Fp + (Tf−Tb) / 2} may remain. Work roll 1 by this horizontal force
Although the deflection is suppressed by the horizontal bending control started in the step S206, as described above, the horizontal bending control does not cancel out the horizontal force itself.

In this embodiment, the procedure S2
08 onward, the pressing control unit 101e uses the hydraulic cylinders 23a,
23b, and controls the horizontal force detectors 40a and 40b.
Is controlled so that the detected horizontal force becomes a target value (D tons after driving starts, for example, D ≒ several tons, see FIG. 5 (e)). That is, as shown in FIG. 5 (c), the pressing force of the pressing cylinder 23 is rapidly reduced in accordance with the generation of the driving tangential force Ft due to the start of driving, and the pressing cylinder 23 is controlled in accordance with the remaining horizontal force H at this time. 23 was changed with good responsiveness, and FIG.
As shown in (d), the horizontal force detected by the horizontal force detector 40 is maintained at a target value (D ton). Thereby, separation of the work roll 1 from the support rolls 13a and 13b, which may occur when the horizontal force H in the left direction in FIG. 7 is generated, can be reliably prevented. Further, at this time, the following inconvenience which may occur when the horizontal force H in the right direction in FIG. 7 is generated can also be prevented.

In other words, if the horizontal force H in the right direction in FIG. 7 becomes extremely large momentarily due to some unexpected factor, a large load is applied to the bearings of the support rolls 13a and 13b, and the life thereof is greatly reduced. However, in severe cases, the possibility of breakage is inevitable. In the present embodiment, such a bad influence on the bearing can be prevented by the above-described pressing control in which the horizontal force detected by the horizontal force detectors 40a and 40b is made substantially constant.

(B) Immediately after the start of rolling and immediately before the end of rolling As shown in FIG.
After the start of driving, the driving speed is accelerated to gradually increase the rolling speed to the set rolling speed. Immediately before rolling is completed after performing a predetermined rolling process, the driving speed is reduced to gradually reduce the rolling speed. Therefore, in these cases, the change in the rolling state is largely unstable compared to the steady rolling state. In addition, when used as a reversible rolling mill, the beginning and end of the rolled material are usually slightly thicker than the regular sheet thickness. It tends to be unstable compared to Therefore, immediately after the start of rolling and immediately before the end of rolling, the horizontal force H = Ft− {Fp + (Tf−Tb) / 2}.
And the value thereof is larger than that at the time of steady rolling and tends to change rapidly. Then, when the magnitude of the horizontal force becomes extremely large instantaneously, in the case of the left direction in FIG.
7, in the case of the right direction in FIG.
The load on the bearings 13b, 15a, and 15b may increase.

In the present embodiment, as described above,
Immediately after the start of the rolling and immediately before the end of the rolling, the horizontal force H as shown in FIG. 5 (d) is controlled by pressing the horizontal force detectors 40a and 40b to make the detected horizontal force substantially constant (target value = D ton). Is maintained substantially constant, such adverse effects can be prevented.

(C) End of Rolling At the end of rolling, the procedure is basically the reverse of that at the start of rolling described in (A) above, and the mechanism by which horizontal force can be generated and the principle of preventing adverse effects due to this are also the same. It is.

(C-1) At the end of rolling This is a reverse procedure of the above-described steps S210 and S209. First, the offset control section 101a ends the offset control for controlling the offset amount of the work roll 1. Thereafter, the rotation control unit 101d outputs a signal to stop driving the intermediate roll 3 to the motor 5, the motor 5 stops, the intermediate roll 3 and the work roll 1 stop, and the rolling of the rolled material 11 stops. As a result, the driving tangential force Ft described with reference to FIG.
Disappears, the hydraulic cylinders 23a, 23
If 3b presses at a constant pressure, the work roll 1 may be separated from the support rolls 13a and 13b as in the above (A-1). In the present embodiment, the pressing control unit 101e determines that the horizontal force detected by the horizontal force detectors 40a and 40b is equal to the target value (E ton, for example, E ≒ D-5, FIG.
(see (e)) (see FIG. 5 (c)), the pressing force of the hydraulic cylinders 23a and 23b is increased. Thereby, the above possibility can be prevented beforehand.

(C-2) Post-processing after the end of rolling After the above-mentioned driving stop, the load control unit 101b gradually reduces the rolling load from a predetermined rolling load P (P = 300 to 500 tons). Go. Thereby, the horizontal force based on the load component Fp also decreases. Accordingly, FIG. 5 (c)
As shown in FIG.
3a, 23b, and the horizontal force detector 40
a, and maintain the detected horizontal force at the target value (see FIG. 5).
(d)). Then, the pressing control by the pressing control unit 101e ends when the predetermined second rolling load is sufficiently small (C tons, for example, C ≒ A-10 in this embodiment, see FIG. 5A). Thereafter, the horizontal bending control is terminated, the rolling load is reduced to zero, and predetermined processing and work such as replacement of the work roll 1 are performed.

As described above, according to the rolling mill of the present embodiment, in a discontinuous and unstable rolling state such as at the start of rolling, at the start of rolling, immediately after rolling, immediately before rolling, or at the end of rolling. Even so, the generation of a transient and large horizontal force of the work roll 1 can be prevented, and the deflection reduction effect by the offset control and the horizontal bending control can be sufficiently ensured. Further, at the start of rolling, the rolling is started in a state where the horizontal force is sufficiently reduced.
Instability such as poor shape does not occur and rolling can be started stably. Further, since the rolling is started from the state where the predetermined rolling load P is applied to the rolled material 11, the thickness of the predetermined rolled material 11 can be obtained immediately after the start, and the yield is not reduced. And
In this way, it is possible to use a rolling mill capable of high-load rolling with extremely small-diameter work rolls, so that it is possible to increase the rolling reduction in one rolling in an actual operation,
Productivity can be significantly improved.

Further, in the present embodiment, the following effects are obtained by setting the target value of the horizontal force detected by the horizontal force detectors 40a and 40b at the time of driving in the step S200 shown in FIG. Play. That is, in the rolling mill of the present embodiment, the deflection detector 36 as a distance sensor is attached, and the presence or absence of the deflection of the work roll is detected by a change in the distance from the sensor to the work roll. Then, as shown in steps S203 to S205, the detection distance when a predetermined light load is applied before the start of rolling is set as a reference value, and the difference between the reference value and the detection distance after the start of rolling is used as the work during rolling. The presence or absence of the deflection of the roll 1 is detected. However, strictly speaking, the entry-side support frame 1
8 and the support rolls 13a, 13b have slight elastic deformation, so that even if the work roll 1 is not bent, the entry-side support frame 18 and the support rolls 13a, 13b
If a larger horizontal force is applied to b than when the light load is applied, elastic deformation corresponding to the difference in the force is increased in the entry-side support frame 18 and the support rolls 13a and 13b. Then, since the detection distance of the deflection detector 36 changes by this amount, the deflection detector 36 may erroneously detect that the work roll 1 is bent. In the present embodiment, the pressing control is performed with the D-ton, which is the detection value of the horizontal force detectors 40a and 40b when the light load is applied, as the target value, so that the entrance support frame 18 and the support roll 1 can be used.
It is possible to prevent an increase in elastic deformation of 3a and 13b, and to prevent the occurrence of a deflection detection error during the pressing control.

It is needless to say that the same effect as described above can be obtained also in the control relating to the configuration related to the lower work roll 1 side of the rolling mill.

Further, in the above embodiment, in the control flow shown in FIG. 6, when the operator inputs the rolling conditions and the like from the input means 102, all the procedures after the step S200 are automatically executed. The present invention is not limited to this, and a part thereof may be manually operated. That is, for example, when the worker inputs the rolling conditions and the like, steps S200 to S208 are automatically executed, and then the apparatus enters a standby state. When the worker inputs a rolling start instruction again, steps S209 and subsequent steps are restarted. May be performed. In these cases, a similar effect is obtained.

Furthermore, in the rolling mill of the above embodiment, the offset positions of the work rolls 1 and 2 during rolling can be made variable by the positioning devices 9 and 10, but the present invention is applied to such a case. It is not necessarily limited to a simple rolling mill. That is, the present invention can be applied to a rolling mill having a fixed offset position. In this case, the bending reduction effect by the fixed offset can be sufficiently ensured even in a discontinuous rolling state by the pressing control according to the present invention.

Further, in the above embodiment, the pass direction of the rolling mill has been described as fixed (shown as "left pass" in FIG. 5).
In the case where the offset position can be positioned on the opposite side by a method as disclosed in Japanese Patent Publication No.
(Shown as "right path" in the figure). The operation flow in this case is indicated by a broken line in FIG.
That is, it is sufficient that the target value of the horizontal force detected by the horizontal force detectors 40a and 40b is the same D ton both before and after the start of the work roll. The significance of changing the setting method of the target value depending on the pass direction is as follows.

As shown as "right pass", when the work roll 1 is offset to the right in FIG. 5, the horizontal force transiently increases in the right direction in many cases.
In this case, in the above-described pressing control, the hydraulic cylinder 2
For 3a and 23b, it suffices to press rightward with a force of (target value)-(horizontal force to the right). On the other hand, "Left pass"
As in the above embodiment shown in FIG.
When offset to the middle left side, the horizontal force tends to transiently increase in the left direction, but in this case,
In the pressing control, the hydraulic cylinders 23a and 23b are set to (target value) + (horizontal force to the other side) in order to oppose this.
It is necessary to press to the left with the force of

Therefore, if the target values in the two offset patterns are the same, the pressing force required by the pressing cylinders 23a and 23b becomes extremely large in the latter (left pass) of the two, and the supporting rolls 12a and
A heavy load is applied to the bearing 12b. Therefore, in this embodiment, when the work roll 1 is used as a reversible rolling mill, the target value is changed according to the pass direction of the rolling mill when the work roll 1 is not driven. Pressing control is performed by setting the target value itself to E ton lower than the right pass. Thereby, the above-described pressing cylinders 23a, 2
Since the pressing force required for 3b can be reduced, the load on the bearings of the support rolls 12a and 12b can be reduced.

Further, in the above-described embodiment, the pressurized oil supply control is performed on the pressing hydraulic cylinders 23a and 23b by one proportional electromagnetic pressure reducing valve 39 and the amplifier 41. However, the present invention is not limited to this, and as shown in FIG. The proportional electromagnetic pressure reducing valves 39, 42 are respectively connected to the pressing hydraulic cylinders 23a, 23b.
And these may be controlled by the amplifiers 41 and 43, respectively. The control flow performed by each of the amplifiers 39 and 41 in this case is as shown in FIG. In this case, the same effect as in the above embodiment is obtained.

In the above-described embodiment, the positioning device 9 including the drive motor 9a, the gear mechanism 9b, and the worm jack mechanism 9c is used as the offset support means and the offset positioning means related to the offset control. Alternatively, for example, as shown in FIG. 15, hydraulic cylinders 44a and 44b provided with cylinder position detectors 48a and 48b may be used. In this structure,
The offset position of the work roll 1 is controlled as follows. That is, the offset control unit 101a outputs a signal indicating the rolling condition from the input unit 102 (that is, a target value of the pressure difference between the bending cylinders 7a and 7b in the offset control) and the pressure oil supplied to the upper bending cylinders 7a and 7b. A detection signal from the pressure sensors 32a and 32b for detecting pressure is input, and a target offset amount signal corresponding to a difference between the target value and the detection signal of the pressure sensors 32a and 32b is output to the servo amplifier 46.

The servo amplifier 46 responds accordingly to the operation shown in FIG.
The control as shown in FIG. 6 is started. That is, in FIG. 16, first, in step S600, the cylinder position detector 48a,
48b, and inputs the detection signal from Steps S601 and S6.
In step 02, the sum of the detected cylinder positions (that is, the offset amount) is calculated, and then multiplied by (1/2).
At 03, a deviation between the target offset amount and the target offset amount input from the offset control unit 101a is determined. And step S
Moving to step 604, a current signal proportional to the deviation is supplied to the servo valve 45.
Output to Thereby, the corresponding hydraulic cylinder 44
The pressurized oil is supplied to a and 44b, and as a result, the support frame 18 is moved to an offset position where the deflection of the work roll 1 is reduced. When the procedure 604 is completed, the procedure returns to the procedure 600, and the same procedure is repeated.

This control is performed as shown in FIG.
Since a closed loop in which analog signals from the cylinder position detectors 48a and 48b are fed back to the servo valve 45 by a hardware circuit in the servo amplifier 46, relatively high-speed control is possible. The detection of the horizontal force used for the pressing control is performed by a horizontal force detector 40 which is a load cell.
a, 40b instead of the hydraulic cylinders 44a, 44b
The detection signals are inputted to the amplifier 41. According to such a modification, the same effect as in the above embodiment can be obtained.

Further, the above modification is further modified,
As described above with reference to FIGS. 13 and 14, two proportional electromagnetic pressure reducing valves and two amplifiers are provided to press the pressing cylinders 23a and 23b.
May be individually controlled.

[0080]

According to the present invention, even in a discontinuous rolling state, it is possible to sufficiently secure the deflection reduction effect by offset control or the like.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a rolling mill according to an embodiment.

FIG. 2 is a side view illustrating a main structure of the rolling mill illustrated in FIG.

FIG. 3 is a top view of a portion related to an upper work roll in the structure of FIG. 2 when an intermediate roll and a reinforcing roll (described later) are removed.

FIG. 4 is a block diagram illustrating functions of a controller illustrated in FIG.

FIG. 5 is an operation flow from the start of rolling to the end of rolling.

FIG. 6 is a flowchart showing a control procedure of a controller at the start of rolling.

FIG. 7 is a diagram showing a balance state of a rolling load component force Fp, a driving tangential force Ft, a front tension Tf, and a rear tension Tb assumed when the initial offset amount δ is determined.

FIG. 8 is a flowchart showing a control procedure of a servo amplifier for horizontal bending control.

FIG. 9 is a view showing a state in which horizontal deflection has been corrected by applying a horizontal bending force before starting rolling.

FIG. 10 is a flowchart illustrating a control procedure of a pressing control amplifier.

FIG. 11 is a flowchart illustrating a procedure of offset control executed by an offset control unit of the controller.

FIG. 12 is a view showing a state in which the horizontal force is zero, with the rolling load component Fp, the driving tangential force Ft, the front tension Tf, and the rear tension Tb being completely balanced.

FIG. 13 is a diagram showing a modification in which two proportional electromagnetic pressure reducing valves and two amplifiers are provided.

FIG. 14 is a flowchart showing a control procedure executed by a pressing control amplifier in the modification shown in FIG.

FIG. 15 is a view showing a modification in which a hydraulic cylinder is provided instead of the positioning device.

FIG. 16 is a flowchart showing a control procedure executed by a positioning servo amplifier in the modification shown in FIG. 16;

FIG. 17 is a diagram illustrating the principle of conventional offset control.

FIG. 18 is a view showing a main structure of a rolling mill described in Japanese Patent Application Laid-Open No. 9-285804.

[Explanation of symbols]

1, 2 work roll 3, 4 intermediate roll (drive roll) 7a, b bending cylinder (horizontal bending means) 8a, b bending cylinder (horizontal bending means) 9, 10 positioning device (offset positioning means) 9a drive motor 9c worm Jack mechanism 12a, b Support roll (press support means) 13a, b Support roll (offset support means) 14a, b Support roll (press support means) 15a, b Support roll (offset support means) 17, 19 Entry support frame ( Pressing support means) 18, 20 Outgoing support frame (offset support means) 23a, b Hydraulic cylinder for pressing 24a, b Hydraulic cylinder for pressing 40a, b Horizontal force detector (horizontal force detecting means) 101 Controller 101e Pressing control unit ( Pressing control means)

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Shunji Ohara 3-1-1, Sakaimachi, Hitachi-shi, Ibaraki F-term in Hitachi Plant, Hitachi, Ltd. F-term (reference) 4E024 CC02 DD02 DD03 DD10 EE02

Claims (10)

[Claims] A pair of upper and lower work rolls, a pair of upper and lower drive rolls which respectively contact the work rolls to apply a driving force, and are provided on one of an entrance side and an exit side of the work rolls; Offset support means for supporting the work roll from the one side in a state where the axis of the work roll is offset from the axis of the drive roll in a substantially horizontal direction, and the entry and exit sides of the work roll Pressing support means provided on the other side for supporting the work roll while pressing the work roll from the other side by the pressing force of a hydraulic cylinder, and horizontal force detecting means for detecting a horizontal force acting on the offset support means A rolling mill for reducing the thickness of the rolled material by the work roll, wherein the detected value is larger than the target value so that the detected value of the horizontal force detecting means is maintained at a predetermined target value. A rolling mill further comprising a pressing control means for reducing the pressing force of the hydraulic cylinder when the pressure is large and increasing the pressing force of the hydraulic cylinder when the detected value is smaller than the target value. 2. The rolling mill according to claim 1, wherein the offset support means includes a support roll for supporting both ends of the body of the work roll from the one side outside a maximum plate width of the rolled material. A rolling mill comprising: 3. The rolling mill according to claim 1, further comprising offset positioning means for positioning a position supported by said offset support means. 4. The rolling mill according to claim 3, wherein said offset positioning means includes a drive motor and a worm jack mechanism for moving said offset support means in a substantially horizontal direction based on a driving force of said drive motor. A rolling mill. 5. A pair of upper and lower work rolls, a pair of upper and lower drive rolls respectively in contact with these work rolls to apply a driving force, and provided on one of an entrance side and an exit side of the work rolls, Offset support means for supporting the work roll from the one side in a state where the axis position of the work roll is substantially horizontally offset from the axis position of the driving roll; and positioning the support position by the offset support means. Offset positioning means, and pressing support means provided on the other side of the input side and the output side of the work roll, and supporting the work roll while pressing the work roll from the other side by the pressing force of a hydraulic cylinder, A horizontal force detecting means for detecting a horizontal force acting on the offset support means, and a horizontal bending means for applying a horizontal bending force to the work roll; When the detected value is larger than the target value, the pressing force of the hydraulic cylinder is set so that the value detected by the horizontal force detecting means is maintained at a predetermined target value. And a pressing control means for increasing the pressing force of the hydraulic cylinder when the detected value is smaller than the target value. 6. A pair of upper and lower work rolls, a pair of upper and lower drive rolls respectively in contact with these work rolls to provide a driving force, and provided on one of an entrance side and an exit side of the work rolls, Offset support means for supporting the work roll from the one side in a state where the axis of the work roll is offset from the axis of the drive roll in a substantially horizontal direction, and the entry and exit sides of the work roll A pressure support means provided on the other side for supporting the work roll while pressing the work roll from the other side by a pressing force of a hydraulic cylinder, and a horizontal force detection means for detecting a horizontal force acting on the offset support means In a rolling method using a rolling mill for reducing the thickness of a rolled material by the work roll, the detection value is set so that a detection value of the horizontal force detection unit is maintained at a predetermined target value. A rolling method comprising: performing a pressing control to decrease the pressing force of the hydraulic cylinder when the detected value is larger than the target value and to increase the pressing force of the hydraulic cylinder when the detected value is smaller than the target value. 7. The rolling method according to claim 6, wherein when the rolling is started, the rolling load is increased to a predetermined steady rolling load without rotating the driving roll. A rolling method, wherein the pressing control is started at a boundary of the rolling. 8. The rolling method according to claim 6, wherein when the rolling is completed, the rolling load is reduced from a predetermined steady rolling load after the rotation of the driving roll is stopped. A rolling method, wherein the pressing control is terminated when a rolling load is applied. 9. The rolling method according to claim 6, wherein when the rolling mill is a reversible rolling mill and the work roll is not driven, the target value is changed according to a pass direction of the rolling mill. A rolling method characterized by performing pressure control. 10. The rolling method according to claim 6, wherein said rolling mill is provided with a work roll deflection detecting means, and applies a predetermined light load to said rolled material before starting rolling. A rolling method, wherein when the detection value of the detection means is used as the detection reference value, the target value in the pressing control is set to a value equal to the detection value of the horizontal force detection means when the light load is applied.