JP6152320B2 - Metal plate rolling method and metal plate rolling machine - Google Patents

Description

The present invention relates to a rolling method for a metal sheet and a rolling machine for the metal sheet.

One technique for rolling a metal plate material by controlling the shape of a plate crown or the like is roll bending that imparts a bending force to a work roll chock. Roll bending machines are usually configured so that the roll bending force can be changed (adjusted) during rolling by controlling a hydraulic cylinder or the like, and this control has high responsiveness to increase the flatness of the plate material. It is requested.

Under such circumstances, an increment bending device that generates an increase bending force (a force in the direction of increasing the roll opening) on the work roll chock and a decrease bending force (a force in the direction of decreasing the roll opening) on the work roll chock. Using a rolling mill equipped with a decrease bending device that generates squeeze, the resultant bending force and the increment bending force are set as roll bending forces, while the decrease bending force is kept substantially constant from before rolling to the end of rolling. A rolling method for adjusting the roll bending force by controlling the increment bending force has been proposed (see Patent Document 1). According to this rolling method, even with a rolling mill whose response of the decrease bending apparatus is low due to structural problems of the rolling mill, etc., a high response can be achieved by the incremental bending apparatus having high response.

Japanese Patent No. 4763100

In the rolling method described in Patent Document 1, since the thrust in the decrease direction (direction in which the roll is closed) is increased as the roll bending force at the start of rolling (when the plate is bitten), only the incremental bending force is rapidly increased. Will be reduced. However, at this moment, the balance between the increase bending force and the decrease bending force is lost, and the reaction force of the hydraulic cylinder (decrease cylinder) that constitutes the decrease bending device is suddenly released. Vibration occurs in the lease cylinder. The vibration of the decrease cylinder hinders the flatness control in rolling. In addition, if the vibration of the decrease cylinder is large, the hydraulic cylinder (increase cylinder) constituting the increase bending apparatus may also generate vibration due to this vibration. In this case, the influence on the flatness control is further increased. .
In this specification, the work roll bending force (during rolling), the (roll) bending force, and the roll balance force are the resultant force, and the force from each device unit is the increment bending device output, the decrease bending device output, To do. Further, the increment bending force is a force in the direction of increasing the roll opening, and the decrease bending force is a force in the direction of decreasing the roll opening.

This invention is made | formed in view of this situation, and it aims at providing the rolling method of the metal plate material which can suppress generation | occurrence | production of the vibration at the time of rolling start, and the rolling machine of a metal plate material.

The method for rolling a metal sheet according to the first invention that meets the above-mentioned object is as follows:
Using a rolling mill comprising an increment bending apparatus for generating an increase bending force for an operation roll chock as an output of an increase bending apparatus, and a decrease bending apparatus for generating a decrease bending force for the work roll chock as an output of a decrease bending apparatus ,
As step (A),
Before starting rolling, by generating both the output of the increase bending device and the output of the decrease bending device, the work using the resultant force of the output of the increase bending device and the output of the decrease bending device as a roll balance force. Act on roll chock,
By reducing the increase bending device output while maintaining the decrease bending device output at the start of rolling, the resultant force acts on the work roll chock as a predetermined work roll bending force during rolling,
During rolling, by controlling the output of the increase bending apparatus, the rolling is performed so as to maintain the predetermined work roll bending force during rolling,
At the end of rolling, by increasing the increase bending apparatus output while maintaining the decrease bending apparatus output, in the rolling method of the metal plate material having the step of acting on the work roll chock as the resultant balance force,
The decrease bending apparatus has a hydraulic cylinder that acts on the work roll chock,
The rolling mill is connected to the hydraulic cylinder via a first valve, and to a conduit connecting the hydraulic cylinder and the first valve so as to be openable and closable via a second valve. An accumulator
The second valve is opened before the start of rolling, and rolling is started with the second valve opened.

According to the rolling method of the metal plate material according to the first invention, since the hydraulic cylinder of the decrease bending apparatus is connected to the accumulator at the start of rolling in the step (A), the hydraulic cylinder (decrease cylinder) The apparent elastic modulus of the hydraulic oil is small. Therefore, the generated vibration is absorbed and the vibration can be suppressed.

In the rolling method for a metal sheet according to the first aspect of the invention, it is preferable that the second valve is closed after the start of rolling and before the end of rolling. If the second valve remains open at the end of rolling (at the end of the bottom), the thrust control ability (thrust reduction speed) in the decrease direction (direction in which the roll is closed) is reduced. Occurrence of collision between each other may occur easily. However, at the end of rolling in this way, by disconnecting the hydraulic cylinder and accumulator of the decrease bending device, the elastic modulus of the hydraulic cylinder, that is, the responsiveness is restored and the occurrence of collision between work rolls is suppressed. Can do.

In the method for rolling a metal sheet according to the first aspect of the invention, the response of the decrease bending apparatus can be made lower than that of the increase bending apparatus. According to the rolling method of the metal plate material according to the first invention, the controllability of the flatness can be enhanced even when the response of the decrease bending apparatus is lower than that of the increment bending apparatus. Moreover, if the response of the decrease bending apparatus is low, vibration at the start of rolling can be further suppressed.

In the rolling method of the metal sheet material according to the first invention, from the viewpoint of controlling the crown and shape of the rolled material (metal sheet material), the step (A) is intended to apply an increase bending force during rolling. Before or after the step (B), wherein the output of the decrease bending apparatus to be generated is smaller than the output of the decrease bending apparatus during the rolling in the step (A), and the rolling is performed by controlling the output of the increase bending apparatus. The rolling mill further includes, as the accumulator, a high pressure accumulator and a low pressure accumulator that are connected to each other so that the pressures are different from each other, and in the step (A), the high pressure accumulator is used, and the step (B) In the above, it is preferable to use the low-pressure accumulator. Thus, only the output of the increment bending apparatus is substantially used, and the output of the decrease bending apparatus is, for example, a step (B) in which rolling is performed with a relatively weak force that only loads the hydraulic cylinder so as not to leave the work roll chock. In some cases, the pressure in the decrease cylinder is low in this step (B). On the other hand, the pressure in the decrease cylinder is high in step (A) in which rolling is performed with the intention of applying a decrease bending force during rolling. Therefore, when switching between step (A) and step (B), it is necessary to change the pressure of the accumulator connected to the decrease cylinder. By switching between the two accumulators with different pressures, the time lag is changed. And switching between processes can be performed smoothly.

A rolling machine for a metal sheet according to the second aspect of the present invention,
An increase bending apparatus for generating an increase bending force for the work roll chock as an output of the increase bending apparatus, and a decrease bending apparatus for generating a decrease bending force for the work roll chock as an output of the decrease bending apparatus, before starting rolling In a rolling mill for a metal plate material that performs rolling by controlling the output of the increase bending apparatus while keeping the output of the decrease bending apparatus constant from the end of rolling to the end of rolling,
The decrease bending apparatus has a hydraulic cylinder that acts on the work roll chock,
A hydraulic pump connected to the hydraulic cylinder via a first valve; and an accumulator connected to a conduit connecting the hydraulic cylinder and the first valve via a second valve so as to be openable and closable. Prepare.

According to the metal sheet material rolling mill of the second invention, in the case where rolling is performed by adjusting the roll bending force by controlling the output of the increment bending apparatus while keeping the output of the decrease bending apparatus substantially constant. Generation | occurrence | production of the vibration at the time of start can be suppressed, and generation | occurrence | production of the collision of the rolls at the time of completion | finish of rolling can be suppressed.

According to the rolling method of the metal sheet material according to the first invention and the rolling machine for the metal sheet material according to the second invention, it is possible to suppress the occurrence of vibration at the start of rolling and the collision between work rolls at the end of rolling. Therefore, according to the present invention, it is possible to perform efficient rolling of a metal sheet with high flatness controllability.

It is a side view which shows the rolling mill of the metal plate material which concerns on the 1st Embodiment of this invention. It is explanatory drawing which shows typically the hydraulic circuit of the rolling mill. (A)-(d) is explanatory drawing which shows time-sequential changes, such as each output in the rolling method (process A) of the metal plate material using the rolling mill. (A)-(d) is explanatory drawing which shows time-sequential changes, such as each output in the rolling method (process B) of the metal plate material using the rolling mill. It is explanatory drawing which shows typically the hydraulic circuit of the rolling mill of the metal plate material which concerns on the 2nd Embodiment of this invention. (A)-(c) is explanatory drawing which shows the analysis result in the example 1 of an analysis. (D)-(f) is explanatory drawing which shows the analysis result in the example 1 of an analysis. It is explanatory drawing which shows the analysis result in the example 2 of an analysis.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment: Metal Sheet Rolling Machine 10>
As shown in FIGS. 1 and 2, the metal sheet rolling mill 10 according to the first embodiment of the present invention is disposed so as to sandwich a pair of upper work roll 11a and lower work roll 11b. It is a multi-stage (4 stage) rolling mill provided with the upper reinforcement roll 12a and the lower reinforcement roll 12b. As the work roll chock, the rolling mill 10 includes an upper work roll chock 13a that rotatably supports the upper work roll 11a and a lower work roll chock 13b that rotatably supports the lower work roll 11b. Furthermore, the rolling mill 10 includes an upper reinforcing roll chock 14a that rotatably supports the upper reinforcing roll 12a, and a lower reinforcing roll chock 14b that rotatably supports the lower reinforcing roll 12b. The rolling mill 10 is rolled by passing the material to be rolled X (metal plate material) from the entry side (right side in FIG. 1) to the exit side (left side in FIG. 1) between the upper work roll 11a and the lower work roll 11b. Is configured to do.

(Increase bending equipment)
The rolling mill 10 serves as an increase bending apparatus, an entry-side upper increase bending apparatus 15a and an output-side upper increase bending that generate an increase bending force for the upper work roll chock 13a (upper work roll 11a) as an output of the increase bending apparatus. The apparatus 16a includes an entry-side lower increase bending apparatus 15b and an exit-side lower increase bending apparatus 16b that generate an increase bending force for the lower work roll chock 13b (lower work roll 11b) as an output of the increase bending apparatus. Each increase bending apparatus 15a, 15b, 16a, 16b is configured to be hydraulically controllable, and has a hydraulic cylinder and a hydraulic pipe acting on each work roll chock 13a, 13b.

The entry-side upper increase bending device 15a and the entry-side lower increase bending device 15b are provided on the entry-side project block 18a that protrudes inside the housing 17 of the rolling mill 10 to the exit-side upper increase bending device 16a and the exit-side increase bending device 16a. The lower side increment bending apparatus 16b is incorporated in an exit side project block 18b that protrudes to the inside of the exit side of the housing 17 of the rolling mill 10.

Here, since each work roll 11a, 11b is worn out by the rolling work, it is necessary to periodically change the roll. However, in the rolling mill 10, since each increase bending device 15 a, 15 b, 16 a, 16 b is incorporated in each project block 18 a, 18 b, the hydraulic piping of each increase bending device is attached and detached when the roll is changed. There is no need. Each increase bending apparatus 15a, 15b, 16a, 16b can be connected to each valve etc. via the fixed hydraulic piping. Accordingly, each of the increase bending apparatuses 15a, 15b, 16a, and 16b can increase the responsiveness.

(Decrease bending equipment)
The rolling mill 10 is, as a decrease bending device, an entry-side upper decrease bending device 19a and an output-side upper decrease bending for generating a decrease bending force for the upper work roll chock 13a (upper work roll 11a) as a decrease bending device output. The apparatus 20a includes an entry-side lower decrease bending apparatus 19b and an exit-side lower decrease bending apparatus 20b that generate a decrease bending force for the lower work roll chock 13b (lower work roll 11b) as a decrease bending apparatus output. . Each decrease bending device 19a, 19b, 20a, 20b is configured to be hydraulically controllable, and includes hydraulic cylinders 21a, 21b (decrease cylinder) and hydraulic piping 24 that act on each work roll chock 13a, 13b (FIG. 2). reference).

The entry-side upper decrease bending device 19a and the exit-side upper decrease bending device 20a are incorporated in the upper reinforcing roll chock 14a. Further, the entry-side lower decrease bending device 19b and the output-side lower decrease bending device 20b are incorporated in the lower reinforcing roll chock 14b. Here, each of the reinforcing rolls 12a and 12b is also worn out by the rolling operation, so that it is necessary to periodically change the rolls. When the reinforcement rolls 12a and 12b are recombined, the hydraulic pipes 24 of the decrease bending devices 19a, 19b, 20a and 20b must be attached and detached. In some cases, it is connected to each valve or the like via a detachable hydraulic pipe. In this case, because of the flexible structure, the fluctuation of hydraulic pressure is absorbed and relaxed. Thus, in the case where flexible piping is adopted as the hydraulic piping 24 of each decrease bending device 19a, 19b, 20a, 20b due to the ease of pipe attachment / detachment at the time of roll change, etc. The responsiveness is lower than the responsiveness of the increment bending apparatuses 15a, 15b, 16a, 16b.

As shown in FIG. 2, the hydraulic cylinders 21a and 21b of the decrease bending apparatuses 19a and 19b are connected to the hydraulic pump 23 via the first valve 22 (the same applies to the decrease bending apparatuses 20a and 20b). The explanation will be omitted because there are. These are connected by a hydraulic pipe 24. The hydraulic pump 23 is configured to pump up working oil stored in the tank 27 and supply pressure oil to the hydraulic cylinders 21a and 21b. The first valve 22 is configured to be able to control the flow rate, pressure and direction of the hydraulic pressure supplied to the hydraulic cylinders 21a and 21b. That is, the first valve 22 can be configured by appropriately combining known flow rate control valves, pressure control valves, directional control valves, and the like. Each of these valves may be a solenoid valve. With such a configuration, it is possible to control the output of the decrease bending device generated by each decrease bending device 19a, 19b.

The rolling mill 10 further includes an accumulator 25 that is connected to a hydraulic pipe 24 (pipe) that connects the hydraulic cylinders 21 a and 21 b and the first valve 22. A second valve 26 is disposed between the hydraulic pipe 24 connecting the hydraulic cylinders 21 a and 21 b and the first valve 22 and the accumulator 25. That is, the accumulator 25 is connected to a pipe line (hydraulic pipe 24) connecting the hydraulic cylinders 21a and 21b and the first valve 22 via the second valve 26 so as to be opened and closed. As the second valve 26, a known directional control valve or the like can be used, and the second valve 26 can be an electromagnetic valve. Furthermore, the rolling mill 10 has control means (not shown) for controlling the opening and closing of the second valve 26. The control means is not particularly limited, and a known one can be used, and the second valve 26 is opened and closed based on a program or the like prepared in advance according to the shape, size, etc. of the material X to be rolled. Has been.

<Rolling method of metal plate>
Next, a method for rolling a metal plate using the rolling mill 10 will be described with reference to FIG.
Advance, then performs the setting calculations corresponding to metal sheet rolling, keep calculating the set value F _R during rolling work roll bending force (see FIG. 3 (d)). Note that the roll bending force (the resultant force) is the increase bending force (the force in the increase direction (the direction in which the roll is opened)), and the decrease bending force (the force in the decrease direction (the direction in which the roll is closed)). and a negative value, F _R is a negative value (decrease-bending force). Further, the control of the increment bending device output (increase bending force) and the decrease bending device output (decrease bending force) are controlled by a valve (the first valve 22 in the decrease bending devices 19a and 19b). ).

Process (A)
As a series of rolling steps, the step (A) of rolling the metal plate material (rolled material) by generating both the output of the increment bending apparatus and the output of the decrease bending apparatus will be described.
(Before rolling: Before point a)
Before starting rolling (before point a on the time axis), both an increase bending device output and a decrease bending device output are generated. The output of the increment bending apparatus is generated by each of the increase bending apparatuses 15a, 15b, 16a, and 16b, and the output of the decrease bending apparatus is generated by each of the decrease bending apparatuses 19a, 19b, 20a, and 20b. Thus, the increase-bending device output and decrease-bending device work roll chock (upper work roll chock 13a, the lower work roll chock 13b) the resultant force of the output as a roll balancing force F _B to act on (see FIG. 3 (d)).

That is, at idle before rolling, the increment bending device output is I _B (> 0), the decrease bending device output is D _B (<0), and I _B + D _B is the roll balance force F _B (> 0). It works (see FIGS. 3B to 3D). Incidentally, the roll balancing force F _B, even in the mill acceleration and deceleration of the idle state, the work rolls 11a, 11b driven by an electric motor, rolls 12a to be driven, 12b and is determined as a force that does not slip. Further, D _B may be set at a level of minimum oil pressure hydraulic cylinder of decrease-bending device (actuator) is not Shimawa away from the work roll chock.

(Point a)
Then, in a rolling immediately before the start timing (a point on the time axis), decrease-bending device output sufficient in a given rolling exert work in a given rolling roll bending force F _R (decrease-bending force) the D _S is calculated by _D S ₌ F _R -I R. As the roll balancing force _{(F B)} is constant, at the same time outputs the _{D S} and _{I S} (see FIG. 3 (b) ~ (d) ). Here, I _R is-bending device output during rolling (increase-bending force), determined in advance absolute value close to the controllable minimum so as not to excessive D _S, I _S Is the output of the increment bending apparatus determined to satisfy I _S + D _S = F _B. Therefore, at the setting timing (point a on the time axis), the resultant force remains F _B and does not substantially change.

(X point)
On the other hand, at a certain timing (x point on the time axis) before the start of rolling, the second valve 26 is opened by this control means, and the accumulator 25 is connected to the hydraulic cylinders 21a and 21b. By doing so, the apparent elastic modulus of the hydraulic oil in the hydraulic cylinders 21a and 21b is reduced.

The timing for opening the second valve 26 (point x) is between point a and point b at the start of rolling in FIG. 3, but point b if it is a period before the start of the next rolling pass. It is not particularly limited at any previous time point, and may be before point a. For example, the second valve 26 may be opened after the previous rolling is completed (for example, after several seconds from the end of rolling (c point) (d point: after 1 to 5 seconds), for example). . However, as shown in FIG. 3, it is preferable to open the second valve 26 at a timing after the point a. By doing in this way, the output controllability of the decrease bending apparatus in point a can be improved.

(At the start of rolling: point b)
Then, at the start of rolling (b point on the time axis), while decrease-bending device output performs control to maintain a constant value (while to keep the predetermined value D _S), reduces the increase-bending device output is allowed, is rolling in a state where a predetermined rolling work roll bending force F _R as the resultant force acts on the work roll chock. That is, in the rolling start timing (b point on the time axis), the increase-bending device output decreases from I _S to I _R. In this way, the slow decrease-bending device output response remains D _S, the control of the quick-bending apparatus responsive, the work roll bending force roll balancing force F _B as the resultant force _(> 0) To the predetermined work roll bending force F _R (<0) during rolling in the decrease direction. At the start of rolling, the apparent elastic modulus of the hydraulic oil in the hydraulic cylinders 21a and 21b is reduced as described above, so that the hydraulic cylinders 21a and 21b are generated along with a sudden decrease in the output of the increment bending apparatus. Vibrations that are absorbed are absorbed and vibrations can be suppressed.

In addition, the rolling start time (b) refers to the time point when the rolling is started, and the detection thereof is, for example, the load detected by the load cell for measuring the rolling load of the rolling mill is the rolling load predicted and calculated by the setting calculation. What is necessary is just to determine by the method of setting it as the timing which exceeded predetermined ratio (for example, 30%) (refer Fig.3 (a)). This value is preferably set between 10 and 30%.

(Y point)
Next, at a certain timing (y point on the time axis) after the start of rolling (point b), the second valve 26 is closed by this control means, and the accumulator 25 is shut off from the hydraulic cylinders 21a and 21b. By this interruption, the apparent elastic modulus of the hydraulic oil in the hydraulic cylinders 21a and 21b, which has been reduced at the start of rolling, is restored.

The timing for closing the second valve 26 (point y) is preferably after the start of rolling (point b) and before the end of rolling, but is preferably immediately after the start of rolling. Thus, by closing the second valve 26 immediately after the start of rolling, the response of the decrease bending apparatuses 19a and 19b during rolling can be ensured, and the controllability of flatness can be improved. Note that “immediately after the start of rolling” can be a timing when the output of the decrease bending apparatus or the resultant force is substantially stabilized after the start of rolling (point b). Specifically, the time from the point b to the point y can be 0.1 seconds or more and 0.5 seconds or less.

(During rolling)
During rolling, by controlling the increase-bending device outputs (increase-bending force) is rolling so as to maintain a predetermined rolling work roll bending force F _R. In addition, since the 2nd valve | bulb 26 is closed during rolling, the responsiveness of the decrease bending apparatuses 19a and 19b during rolling can be ensured, and the controllability of flatness can be improved.

(End of rolling: c point)
During completion of rolling (c point on the time axis), by increasing the increase-bending device outputs while maintaining the decrease-bending device output, work roll chock 13a of the resultant force as the roll balancing force F _B, to act on 13b. That is, in the rolling end timing (c point), while the decrease-bending device output D _S, back to I _S fast-bending device output response from the I _R. In this way, the resultant force can be quickly switched from the predetermined work roll bending force F _R (<0) during rolling in the decrease direction to the roll balance force F _B (> 0).

At the end of rolling (point c), the elastic modulus, that is, the responsiveness of the hydraulic cylinders 21a and 21b is recovered by disconnecting the hydraulic cylinders 21a and 21b and the accumulator 25 of the decrease bending apparatuses 19a and 19b. it can. Therefore, it is possible to suppress the occurrence of collision between the work rolls 11a and 11b, which may be caused by a sudden loss of the reaction force of the rolling material (metal plate material) at the end of rolling.

The detection at the end of rolling (point c on the time axis) indicates that the load detected by the load cell for measuring the rolling load of the rolling mill 10 falls below, for example, 50% of the value obtained by averaging the actual rolling load during rolling in time series. It may be determined by a method of setting the timing (see FIG. 3A). This value can be set arbitrarily, but is preferably set between 50% and 80%.

(Point d)
Then, for example, the time when 1 to 5 seconds have elapsed from the rolling end timing (point c) is set as the work completion timing (point d). At this timing, the increment bending apparatus output is I _B and the decrease bending apparatus output is D. _B. This change work roll bending force of the resultant force is substantially maintained in the roll balancing force F _B.

Thus, according to the rolling method of the metal plate material using the rolling mill 10, since the hydraulic cylinder of the decrease bending apparatus is connected to the accumulator at the start of rolling, the hydraulic cylinder (decrease cylinder) The apparent elastic modulus of the hydraulic oil is small. Therefore, vibration generated at the start of rolling is absorbed, and vibration can be suppressed. On the other hand, in the present embodiment, at the end of rolling, the connection between the hydraulic cylinder of the decrease bending apparatus and the accumulator is disconnected, so that the elastic modulus of the hydraulic cylinder, that is, the responsiveness is restored, The occurrence of a collision can be suppressed. Furthermore, by reducing the apparent elastic modulus of the hydraulic oil in the decrease cylinder at the start of rolling, the thrust settling time can be shortened and the overshoot amount (thrust momentarily exceeding the target load) can be reduced. Can do. For this reason, it is possible to stabilize the thrust at the start of rolling.

Further, according to this rolling method, even if the responsiveness of the decrease bending devices 19a, 19b, 20a, and 20b is lower than that of the increment bending devices 15a, 15b, 16a, and 16b, the controllability of flatness is achieved. Can be increased. In addition, when the response of the decrease bending apparatus is low in this way, the apparent elastic modulus is low, and vibration at the start of rolling can be further suppressed.

The control of the increment bending apparatus output is performed by measuring the hydraulic pressure in the hydraulic cylinders 21a, 21b of the decrease bending apparatuses 19a, 19b, 20a, 20b or in the hydraulic piping 24 connected to the hydraulic cylinders 21a, 21b. It is preferable that the resultant force acting on the work roll chock 13a, 13b is based on the measured value so that the resultant value becomes a predetermined value. That is, as the resultant force before and after rolling is rolled balancing force F _B, as the work roll bending force for during rolling becomes F _R, the increase-bending device output, the hydraulic pressure in the hydraulic cylinder of the decrease-bending device It is good to control according to etc. If the response of the decrease-bending device is low, due to a rapid change of the ink bending device in point b and point c on the time axis of FIG. 3, the decrease-bending device output varies, the resultant force in point b F _R from reaching behind the resultant force is the delay to reach the F _B in point c. However, as described above, the output of the increment bending device 15a, 15b, 16a, 16b is supplied to the hydraulic cylinder 21a, 21b of the decrease bending device 19a, 19b, 20a, 20b or the hydraulic pressure connected to the hydraulic cylinder 21a, 21b. By controlling in accordance with the hydraulic pressure in the pipe 24, the increase bending apparatus compensates for the fluctuation in the decrease bending apparatus output, and the resultant force (work roll bending force) can be controlled with high response. In addition, it is possible to predict the fluctuation of the decrease bending device output in advance and set the increment bending device output to compensate for it without the need for measurement of the decrease bending device output during rolling or feedback control by hydraulic pressure measurement. However, the same effect can be obtained.

(Process B)
Unlike the step (A), the rolling method of the metal plate material using the rolling mill 10 is to apply only a small amount of force to the decrease bending device output in a series of rolling steps, and to output only the increment bending device output. There is also a method of controlling and rolling (step B). This step (B) is performed with the intention of applying an increase bending force from the viewpoint of controlling the crown and shape of the rolled material (metal plate material), and FIGS. 4 (a) to 4 (d) are performed. The description will be given with reference. The increment bending apparatus 15a, 15b, 16a, 16b generates an increment bending apparatus output at a predetermined output during rolling (at least from the start of rolling (b point) to the end of rolling (c point)). (See FIG. 4 (b)). On the other hand, in the decrease bending apparatus 19a, 19b, 20a, 20b, the output of the decrease bending apparatus is constant at Ds during a series of rolling processes (see FIG. 4C). The output of the decrease bending apparatus (Decrease Bending Force) Ds during the step (B) is from the output of the Release Bending Apparatus (Decrease Bending Force, Ds in FIG. 3C) during rolling in the process (A). small. If the decrease bending apparatus output Ds in the process (B) is 0, the hydraulic cylinder may be separated from the work roll chock. For this reason, a small thrust (Ds) is loaded so as not to interfere with the control of the output of the increment bending apparatus. In step (B), the work roll bending force is controlled only by the increment bending apparatus.

In the rolling mill 10, as described above, the responsiveness of the increment bending apparatuses 15a, 15b, 16a, and 16b is higher than the responsiveness of the decrease bending apparatuses 19a, 19b, 20a, and 20b. Therefore, when the increase bending force is applied as the work roll bending force during rolling, it is not necessary to use the increase bending apparatus and the decrease bending apparatus in combination. Therefore, in the step (B), the bending force is not used substantially in this way (only by applying a load that does not allow the decrease cylinder to be separated from the work roll chock), and the bending force can be obtained only with the increment bending device. Is controlling.

<Second Embodiment: Metal Plate Rolling Machine 30>
Next, a metal sheet rolling mill 30 according to a second embodiment of the present invention will be described. The metal sheet rolling mill 30 is the same as the metal sheet rolling mill 10 according to the first embodiment except for the hydraulic circuit shown in FIG.

As shown in FIG. 5, the hydraulic cylinders 21a and 21b of the decrease bending devices 19a and 19b of the rolling mill 30 for metal sheet material are connected to the hydraulic pump 23 via the first valve 22 '(decrease). Since the bending apparatuses 20a and 20b are the same, the description thereof will be omitted. These are connected by a hydraulic pipe 24. The hydraulic pump 23 is configured to pump up working oil stored in the tank 33 and supply pressure oil to the hydraulic cylinders 21a and 21b. The rolling mill 30 is configured such that the discharged working oil is accumulated in the tank 34. Further, the rolling mill 30 further includes two accumulators 31 and 32 that are connected to a hydraulic pipe 24 (pipe) that connects the hydraulic cylinders 21a and 21b and the first valve 22 '. Two accumulators 31 and 32 having different capacities such as capacity and filling pressure are used. A second valve 26 is arranged between the hydraulic pipe 24 connecting the hydraulic cylinders 21a, 21b and the first valve 22 'and the accumulators 31, 32. Furthermore, the rolling mill 30 has control means (not shown) for controlling the opening and closing of the second valve 26.

Unlike the first embodiment, the metal sheet rolling mill 30 includes a plurality of (two) accumulators 31 and 32 that are switchably connected via the second valve 26. . Thus, the variation of a rolling method can be increased by using the several accumulators 31 and 32 from which a capacity | capacitance, filling pressure, etc. differ. For example, if the pressure of the decrease bending device (decrease cylinder) is dropped with the accumulator connected, the hydraulic oil for the accumulator needs to be filled when the pressure is increased during the next use. For this reason, the time until the pressure rises is slower than when the accumulator is not used. However, two accumulators 31 and 32 are used as in the rolling mill 30, and when the decrease bending apparatus (decrease cylinder) is at a low pressure, the accumulator is connected to the low pressure accumulator (accumulator with a low filling pressure) and the decrease bending apparatus (decrease). When the cylinder) is at a high pressure, the time for filling the accumulator with oil again can be shortened by switching to a high-pressure accumulator (accumulator with a high filling pressure). Further, when accumulators having different capacities are combined, the range of selection of the bulk modulus can be expanded, and rolling can be performed while selecting an effective bulk modulus according to the rolling reaction force.

As a more specific example, using both the above-described increase bending apparatus output and the decrease bending apparatus output, the step (A) of performing rolling by applying the decrease bending force and the output of the increase bending apparatus substantially. Thus, in the case of a rolling method having both the step (B) of generating and controlling and rolling, the two accumulators 31 and 32 having different pressures can be used effectively. That is, the connection of the two accumulators 31 and 32 is switched so that a high pressure accumulator is used in the step (A) and a low pressure accumulator is used in the step (B). Comparing step (A) and step (B), the pressure in the decrease cylinder is low in step (B) in which rolling is performed substantially using only the output of the increase bending apparatus, and the output of the increase bending apparatus is The pressure in the decrease cylinder is high in the step (A) in which rolling is performed using both the decrease bending apparatus output and the decrease bending force acting. Therefore, when switching between step (A) and step (B), it is necessary to change the pressure of the accumulator connected to the decrease cylinder. Here, when there is only one accumulator, in order to change the pressure, it is necessary to drain and refill the hydraulic oil, so it is difficult to change the pressure quickly. However, by switching and using the two accumulators 31 and 32 having different pressures in this way, the time lag can be reduced and the switching between the processes can be performed smoothly. Specifically, when switching from the step (B) in which the increment bending force is applied to the step (A) in which the decrease bending force is applied, the low pressure accumulator is switched to the high pressure accumulator, and the steps (A) to (A) are performed. When switching to (B), the high pressure accumulator may be switched to the low pressure accumulator.

The present invention is not limited to the above-described embodiment, and the configuration thereof can be changed without changing the gist of the present invention. For example, after the second valve is opened before the start of rolling, the rolling may be performed all the time (from the start of rolling to the end of rolling) with the second valve opened. Even in such a rolling method, since the hydraulic cylinder of the decrease bending apparatus is connected to the accumulator at the start of rolling, the vibration generated at the start of rolling can be absorbed and the vibration can be suppressed. In particular, when the possibility of collision between work rolls is low at the end of rolling even when the second valve is kept open (at the end of the bottom), the opening / closing control of the second valve can be simplified by doing so. Can and is efficient.

The timing for closing the second valve may be just before the end of rolling. In this case, the second valve is open during rolling, and the apparent elastic modulus of the hydraulic oil in the decrease cylinder is in a reduced state. By doing in this way, the vibration which can occur during rolling becomes easy to be absorbed with the decrease cylinder with a low elastic modulus.

Furthermore, in the rolling mill according to the present invention, three or more accumulators connected to the pipe line connecting the hydraulic cylinder and the first valve via the second valve so as to be opened and closed may be provided. In this case, for example, a plurality of accumulators having the same capacity can be used, and the elastic modulus can be adjusted by the number of accumulators to be connected.

Hereinafter, an example of analysis (simulation result) will be given and the operation and effect of the present invention will be described.

<Analysis example 1> Analysis result of bending cylinder thrust at the start of rolling (when biting) (1) Decrease thrust is 350 tonf / chock (Decrease cylinder (Decrease bending device) output 350 tonf, Increase cylinder (Increase bending) Apparatus) The fluctuation of thrust was analyzed as output 0 tonf). In addition, the volume elastic modulus of the oil in the decrease cylinder was changed, and three patterns of high response (high response), medium response (medium response), and low response (low response) were analyzed.

(2) The variation in thrust was analyzed with a decrease thrust of 250 tonf / chock (decrease cylinder (decrease bending device) output 350 tonf, increase cylinder (increase bending device) output 100 tonf). Similar to (1), analysis was performed on the response of three patterns.

The analysis results are shown in FIGS.
In the decrease cylinder of FIG. 6A ((1): high response), large disturbance (vibration) occurs after biting. In the increase cylinder, the disturbance is caused by the disturbance of the decrease cylinder.
In the decrease cylinder of FIG. 6B ((1): medium response), a small disturbance occurs after biting. In the increase cylinder, the disturbance is caused by the disturbance of the decrease cylinder.
In the decrease cylinder of FIG. 6C ((1): low response), the disturbance after the biting is smaller and smaller than that in the case of the medium response. Increase cylinders are not affected by disturbances in the decrease cylinder.
In the decrease cylinder shown in FIG. 7D ((2): high response), large disturbance (vibration) occurs after the biting. In the increment cylinder, after being bitten, it is affected by the disturbance of the decrease cylinder, and a large disturbance occurs without being settled for a while.
In the decrease cylinder shown in FIG. 7 (e) ((2): medium response), a small disturbance occurs after biting. In the increase cylinder, the disturbance is caused by the disturbance of the decrease cylinder.
In the decrease cylinder shown in FIG. 7 (f) ((2): low response), the disturbance after biting is smaller and slightly smaller than that in the case of the medium response. The increase cylinder is slightly disturbed by the influence of the decrease cylinder.
As described above, it can be understood that the lower the responsiveness of the decrease cylinder, the less likely the disturbance (vibration) occurs. Further, it can be seen that if the disorder of the decrease cylinder is large, the increase cylinder is also disturbed.

<Analysis example 2> Stabilization countermeasure analysis The decrease thrust was 250 tonf / chock (decrease cylinder (decrease bending device) output 350 tonf, increase cylinder (increase bending device) output 100 tonf). The variation in thrust (combined force) at the time of biting when ACC was used and when it was not used was analyzed by setting the volume modulus of elasticity of each cylinder as follows.
ACC not used: 16000 kgf / cm ^{2 for} both the increase cylinder and the decrease cylinder (both are highly responsive)
Use of ACC: Increase cylinder 16000 kgf / cm ² , decrease cylinder 5000 kgf / cm ² (low response only for decrease cylinder)
The analysis results are shown in FIG. As shown in FIG. 8, when ACC is used, the thrust stabilization time is shortened by 40 msec, and the overshoot amount is also reduced by 44%. Thus, it turns out that the thrust after biting is also stabilized by using ACC.

10: rolling mill, 11a: upper work roll, 11b: lower work roll, 12a: upper reinforcement roll, 12b: lower reinforcement roll, 13a: upper work roll chock, 13b: lower work roll chock, 14a: upper reinforcement roll chock, 14b: lower Reinforcing roll chock, 15a: entry-side upper increment bending apparatus, 15b: entry-side lower increment bending apparatus, 16a: exit-side upper increment bending apparatus, 16b: exit-side lower increment bending apparatus, 17: housing, 18a: entry Side project block, 18b: Outgoing project block, 19a: Ingress upper decrease bending device, 19b: Ingress lower decrement bending device, 20a: Outgoing upper decrement bending device, 20b: Egress lower decrement bending device , 21a Hydraulic cylinder, 21b: Hydraulic cylinder, 22: First valve, 22 ': First valve, 23: Hydraulic pump, 24: Hydraulic piping, 25: Accumulator, 26: Second valve, 27: Tank, 30: Rolling mill, 31, 32: accumulator, 33, 34: tank, X: material to be rolled

Claims (5)

Using a rolling mill comprising an increment bending apparatus for generating an increase bending force for an operation roll chock as an output of an increase bending apparatus, and a decrease bending apparatus for generating a decrease bending force for the work roll chock as an output of a decrease bending apparatus ,
As step (A),
Before starting rolling, by generating both the output of the increase bending device and the output of the decrease bending device, the work using the resultant force of the output of the increase bending device and the output of the decrease bending device as a roll balance force. Act on roll chock,
By reducing the increase bending device output while maintaining the decrease bending device output at the start of rolling, the resultant force acts on the work roll chock as a predetermined work roll bending force during rolling,
During rolling, by controlling the output of the increase bending apparatus, the rolling is performed so as to maintain the predetermined work roll bending force during rolling,
At the end of rolling, by increasing the increase bending apparatus output while maintaining the decrease bending apparatus output, in the rolling method of the metal plate material having the step of acting on the work roll chock as the resultant balance force,
The decrease bending apparatus has a hydraulic cylinder that acts on the work roll chock,
The rolling mill is connected to the hydraulic cylinder via a first valve, and to a conduit connecting the hydraulic cylinder and the first valve so as to be openable and closable via a second valve. An accumulator
A method for rolling a metal sheet, comprising: opening the second valve before the start of rolling, and starting rolling with the second valve opened. 2. The method of rolling a metal sheet according to claim 1, wherein the second valve is closed after the start of rolling and before the end of rolling. 3. The method for rolling a metal sheet according to claim 1, wherein the responsiveness of the decrease bending apparatus is lower than that of the increment bending apparatus. The said bending bending apparatus in the rolling method of the metal plate material of any one of Claims 1-3 WHEREIN: The said decrease bending apparatus output to generate | occur | produce as a process (B) is the rolling in the said process (A). Smaller than the output, further comprising the step of rolling by controlling the increase bending apparatus output,
The rolling mill includes, as the accumulator, a high-pressure accumulator and a low-pressure accumulator that are connected to each other so that the pressure differs and can be switched,
The method for rolling a metal sheet, wherein the high pressure accumulator is used in the step (A) and the low pressure accumulator is used in the step (B). An increase bending apparatus for generating an increase bending force for the work roll chock as an output of the increase bending apparatus, and a decrease bending apparatus for generating a decrease bending force for the work roll chock as an output of the decrease bending apparatus, before starting rolling In a rolling mill for a metal plate material that performs rolling by controlling the output of the increase bending apparatus while keeping the output of the decrease bending apparatus constant from the end of rolling to the end of rolling,
The decrease bending apparatus has a hydraulic cylinder that acts on the work roll chock,
A hydraulic pump connected to the hydraulic cylinder via a first valve; and an accumulator connected to a conduit connecting the hydraulic cylinder and the first valve via a second valve so as to be openable and closable. A rolling machine for a metal sheet, comprising:

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