JPH03155406A - Plate thickness controller of rolling mill - Google Patents

Abstract

PURPOSE:To elevate the responsiveness for control of plate thickness and to obtain an accurate plate thickness of a product by providing a tension controller to adjust the tension impressed to a rolling material on the inlet side or both inlet and outlet sides of a rolling mill provided with a hydraulic rolling down device. CONSTITUTION:When a roll gap changes, the tension controllers 33, 34 installed on the inlet side or both inlet and outlet sides of the rolling mill provided with a hydraulic rolling down device detects a tension change generated by the result through a load detector 37 of a presser roll 35. Then, the quantity of inflow or outflow of fluid to a hydraulic cylinder 40 is adjusted by a high speed servo valve 42 so that the tension variation conforms to the target value, as a result, a presser roll 35 moved vertically and the tension of a rolled material 30 varies instantly. Consequently, the result of change of a roll gap by hydraulic rolling reduction is reflected instantly on the plate thickness on the outlet side and the plate thickness is controlled in high responsiveness.

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention provides a rolling mill that employs a hydraulic rolling method.
This invention relates to a plate thickness control device that realizes highly responsive plate thickness control.

[Conventional technology]

FIG. 15 shows an example of a jingle stand cold reversible rolling mill with reels arranged on the entry and exit sides as a conventional rolling mill employing the hydraulic rolling method. In this figure, a rolled material 30 is sent out from an unwinding reel 20, passes between a deflector roll 21 and a work roll 3.4, is subjected to a predetermined rolling process, and then passes through a deflector roll 26 and is wound up. is wound onto a reel 27 for use. The unwinding and winding reels 20.27 are driven by motors 19 and 28, respectively, and are further provided with a reel motor tension control device 18.2 for keeping the tension acting on the rolled material 30 constant on the input and output sides of the rolling mill 32.
9 is provided. Tension controllers 18,29 generally control motor current to be proportional to tension. Further, the rolling speed of the line is controlled to a predetermined value by controlling the speed of the work roll drive motor 23 of the rolling mill 32 by a speed control device 24.

In FIG. 15, 1 is a load cell for detecting rolling load, 2 is an upper backup roll, 3.4 is an upper and lower work roll, and 5 is a lower backup roll. 66 is a hydraulic reduction device, 6 is a hydraulic cylinder that sets the roll gap between the work rolls 3.4, 7 is a pipe between the hydraulic cylinder 6 and the servo valve 8, and 9 is a reduction ram 6' installed in the hydraulic cylinder. This is a displacement meter that detects the displacement of 10 is a servo amplifier that sends an opening command (current signal) to the servo valve 8;
1 is a control gain K for amplifying the output signal of the adder/subtractor 12;

The reduction position S of the reduction ram 6' is controlled by a coefficient unit that gives .

The basic position control loop compares and calculates the command signal R and the output signal S of the displacement meter 9, and applies the coefficient multiplier 11 to the deviation signal e.
and gain K. Servo amplifier 1 is multiplied by this signal.
The position of the reduction ram 6' is controlled by controlling the opening degree of the servo valve 8 via the servo valve 0 to adjust the amount of pressure oil supplied from the pipe 7 to the hydraulic cylinder 6. As a result, the lower backup roll 5. The lower work roll 4 is moved so that the opening degree (roll gap p) between the upper and lower work rolls 3 and 4 is adjusted to a predetermined value.

Moreover, if only the position S of the rolling ram 6' is controlled, an error will occur in the roll gap between the work rolls 3 and 4 corresponding to the elongation of the mill subjected to the rolling load.

Therefore, normally, the standard rolling load P is memorized at a certain timing after the start of rolling, and the difference ΔP between the rolling load detected by the load cell 1 and the rolling load during rolling is determined by the adder/subtractor 17, and then the mill constant is calculated by the coefficient unit 16. Find the elongation of the mill by dividing it by Km (which corresponds to the spring constant of the rolling mill and should be determined in advance), and then multiply it by the correction gain C that determines the percentage to be corrected to determine the position S of the rolling ram 6'. A correction signal C1 to be corrected is obtained and given as a command to the previous basic position control loop to correct the lowering ram position S.

Furthermore, in order to match the absolute thickness of the rolled material 30 on the exit side of the rolling mill 32 with the target value h, a thickness gauge 25 is installed on the exit side of the rolling mill er 32 (thickness gauge 22 is used when running in the reverse direction). ) is compared with the target value h by the adder/subtractor 31 to obtain the deviation Δhef.
Correction gain + (M/K
e) to obtain a correction signal ch for correcting the position of the reduction ram 6', and this is also given as a command to the basic position control loop described above to correct the reduction ram position S. Here, M is a constant representing the hardness of the rolled material 30 and is determined in advance.

Ke is a controlled Mill constant and has a relationship of Ke-Km/(1-C).

[Problem that the invention sought to solve]

In order to control the thickness of the rolled material 30 in the rolling mill shown in FIG. 15, when the position S of the rolling ram 6' is changed and the roll gap is changed, the tension acting on the rolled material 30 on the entry and exit sides also changes. . For example, if the roll cap between the work rolls 3 and 4 is narrowed in order to reduce the thickness of the rolled material 3.
0 expands and the tension on the entry and exit sides decreases. Rewinding on the input/output side,
The response of the tension control device 18.29 that controls the motors 19, 28 of the take-up reel 20.27 is generally an order of magnitude or more slower than the hydraulic pressure reduction, so even if the roll gap is changed and the tension is changed, the response will not be the same as the hydraulic pressure reduction. The tension cannot be returned to the set value at this speed. Therefore, the tension on the entry and exit sides decreases, and as a result, an effect appears as if the deformation resistance of the top rolled material 30 has increased, and the roll gap tends to expand (the board thickness does not become thinner). In other words, even if you try to thin the plate under high-speed hydraulic pressure, the reel motor on the input and output side
This means that the plate thickness cannot be reduced faster than the response of the tension control device No. 8.

It is often heard at rolling sites that no matter how quickly the reduction ram position is controlled using hydraulic reduction, the accuracy of plate thickness control is not as good as expected, and this is for the reasons mentioned above.

FIG. 16 is an example of a simulation performed by the present inventor using a computer, which clarifies the above. The object of the simulation was the jingle stand cold reversible rolling mill shown in Fig. 15, and the set tension on the entry side was 1.3.
67ON, exit side set tension 2.35TON, entrance side plate thickness 0.
Report 52, material with a plate width of 18001 IIm was rolled at a speed of 180
Under the condition that the tl mark thickness is 063 mm at 0 m/min,
This is an example in which the intermediate roll gap is reduced by 10 μm in steps. The response under hydraulic pressure is assumed to have a 90 degree phase delay of 20 Hz in the frequency response, and a step response of 0.04
It is a high-speed device that reaches the target value in less than seconds. Looking at the simulation results, the roll gap was set to 10μ.
When m is changed, the outlet side plate thickness change Δh reaches a steady value in approximately 1 second. The actual hydraulic pressure reduction reaches the target value in 0.04 seconds, but the plate thickness changes only 25 times slower.
This is because, as mentioned above, the response of the tension control devices 18 and 29 on the input and output sides is slow. That is, generally reel 20.
Although the tension of 27 is controlled by keeping the motor current constant, the inertia of the reel 20.27 containing the motors 19 and 28 is quite large, so by current control,
This is because it takes about one second for the circumferential speed of the reel 20, 27 to reach the next steady value that suppresses tension fluctuations.

This invention has been made in view of the above points, and is an attempt to provide a plate thickness control device for a rolling mill that can improve the response of plate thickness control and obtain a highly accurate product plate thickness. .

[Means to solve the problem]

According to the present invention, a rolling mill equipped with a hydraulic rolling device is provided with tension control devices on both the entry side and the entry and exit sides for adjusting the tension applied to the rolled material.

[For production]

According to this invention, since the tension control device is provided on both the entry side or the entry and exit sides of the rolling mill, it is possible to quickly suppress fluctuations in tension due to fluctuations in the roll gap. This makes it possible to take full advantage of the high-speed controllability of hydraulic compression to improve the response of plate thickness control, and as a result, it is possible to obtain a highly accurate product plate thickness.

〔Example〕

(Example 1) FIG. 1 shows an example in which the present invention is applied to a cold reversible rolling mill of a jingle stand. This is the conventional apparatus shown in FIG. 15 in which tension control devices 34 according to the present invention are provided on both the inlet and outlet sides of the rolling mill 32. Components common to those in FIG. 15 are given the same reference numerals and their explanations will be omitted.

One embodiment of the tension control device 33,34 is shown in FIG. In FIG. 2, reference numeral 35 denotes a presser roll that presses down the rolled material 30, and is rotatably supported by an arm 36. 37 is a load detector (load cell) attached to the bearing of the presser roll 35, which detects the reaction force from the rolled material 30. The arm 36 is connected to a lever 38 and rotates around a rotational main shaft 39, thereby raising and lowering the presser roll 35. The lever 38 is connected to a piston rod 41 attached to a hydraulic cylinder 40, and rotates about a rotation main shaft 39 by adjusting the amount of liquid to the hydraulic cylinder 40 with a servo valve 42. As a result, the arm 36, which has become a body, rotates and moves the presser roll 35 up and down. The opening degree of the servo valve 42 is adjusted by calculating the tension T of the rolled material 30 from the reaction force of the rolled material 30 detected by the load detector 37 using the tension calculator 46, and then calculates this by using the tension calculator 46 and the tension setting value T. The comparison wave ef is calculated to obtain the deviation ΔT, this deviation ΔT is multiplied by the coefficient KT by the coefficient unit 44, and the servo valve 42 is controlled via the servo amplifier 43 so that the deviation ΔT becomes zero. be done.

According to the tension control device 33, 34 shown in FIG. 2, when the roll gap changes, the resulting tension change is detected by the load detector 37 in the bearing of the presser roll 35,
The flow of fluid into and out of the hydraulic cylinder 40 is adjusted by the high-speed servo valve 42 so that this matches the target value T ev .As a result, the presser roll 35 moves up and down, and the tension of the rolled material 30 is immediately increased. change. Therefore, the result of changing the roll gap under hydraulic pressure is immediately reflected in the exit side plate thickness, allowing for highly responsive plate thickness control compared to the case where a conventional tension control device using motor current is used.

It should be noted that in the apparatus of FIG. 1, reel motor tension controllers 18, 19 act to suppress slow tension fluctuations, and tension controllers 33, 34 act to absorb fast tension fluctuations.

Figure 3 shows the rolling mill 3 in Figure 15 under the same conditions as Figure 16.
This is a simulation example in which the response of the reel motor tension control device 18 and 29 on the input and output side of 2 is made three times faster. Compared to the simulation example shown in FIG. 16, when the roll gap is decreased stepwise by 10 μmfa, the exit side plate thickness Δh reaches a steady value approximately three times faster, approximately 0.3 seconds later.

Since the tension control devices 33 and 34 in Fig. 2 can have high response comparable to hydraulic pressure, the tension control devices 33 and 34 in Fig.
Furthermore, the plate thickness can be controlled by suppressing tension fluctuations at high speed.

FIG. 4 shows that in the rolling mill of FIG. 15, the response of the inlet reel motor tension control device 18 is the same as that of FIG. 16;
This is a simulation example where only the response of the output side tension control device 29 is made three times faster. In contrast, the response of the two output side reel motor tension control devices in FIG. 16 is the same as in the case of input. This is a simulation example in which only the side reel motor tension control device 18 performs tension control by making the response three times faster.

As can be seen from FIGS. 4 and 5, by simply controlling the tension at high speed at the entrance side of the rolling mill, which has a greater effect on the deformation resistance of the rolled material 30 than at the exit side, the tension at both the entrance and exit sides shown in FIG. It can be seen that the same effect as high-speed control can be obtained.

From this, among the tension control devices 33 and 34 on the entry and exit sides shown in the embodiment of the present invention in FIG. 1, in the case of the rolling direction shown in the figure, sufficient effects can be obtained even if only the tension control devices 33 on the entry side are used. It can be seen that the following can be obtained. In addition, in a reversible rolling mill, it is necessary to install tension control devices 33 and 34 on both the input and output sides of the rolling mill, but in an irreversible rolling mill that rolls in only one direction, the tension control devices 33 and 34 are installed only on the input and output sides. You can just set it up.

(Example 2) Another example of the present invention is shown in FIG. This is because the tension control device 48, 49 detects the tension of the rolled material 30 by the load detector 50 attached to the differential crawler 21°260 bearing, and adjusts the amount of pressing down of the presser roll 35 based on this detection. It is designed to control the tension of 30 degrees. The same reference numerals are used for parts common to the first embodiment.

An embodiment of the tension control device 48, 49 of FIG. 6 is shown in FIG. In FIG. 7, reference numeral 35 denotes a presser roll that presses the rolled material 30, and is rotatably supported by an arm 36. 5
0 is a load detector attached to the bearing of the deflation crawler 21, 26, which detects the reaction force from the rolled material 30.

The arm 36 is connected to a lever 38 and rotates around the main shaft 3.
9, and as a result, the presser roll 35 is moved up and down. The lever 38 is connected to a piston rod 41 attached to a hydraulic cylinder 40, and rotates about three main shafts by adjusting the amount of liquid to the hydraulic cylinder 40 with a servo valve 42. As a result, arm 3 became one
6 rotates to move the presser roll 35 up and down. Servo valve 42
To adjust the opening, the tension T of the rolled material 30 is calculated by the tension calculator 46 from the reaction force of the rolled material 30 detected by the load detector 50, and this is calculated by the tension setting value T and the addition/subtraction ref' device 45. A comparison operation is performed to obtain a deviation ΔT, and this deviation ΔT is multiplied by a coefficient KT using a coefficient unit 44.
By controlling the servo valve 42 via the deviation ΔT
is controlled so that it becomes zero.

According to the tension control device 48, 49 shown in FIG.
0, and the high-speed servo valve 42 adjusts the amount of fluid flowing into and out of the hydraulic pressure cylinder 40 so that it matches the target value T. As a result, the presser roll 35 moves up and down, and the rolled material 30 tension changes instantly. Therefore, the result of changing the roll gap under hydraulic pressure is immediately reflected in the exit side plate thickness, and the
Similarly, when used in conjunction with a conventional motor current-based tension control device, highly responsive sheet thickness control can be achieved.

(Example 3) Yet another embodiment of the invention is shown in FIG.

This is an example in which a fluid film is used instead of a presser roll as the tension control device 61, and includes a fluid pad 57, a control valve 58, a fluid source 59, and a pipe 60 connecting these. The same reference numerals are used for the parts common to those in Example 1.2.

The fluid pad 57 injects fluid supplied from five fluid sources via the control valve 58 onto the lower surface of the rolled material 30, supports the rolled material 30 with the pressure, and applies tension. Load detector 50
is attached to the bearing of the differential crawler 21°37 to detect the reaction force from the rolled material 30.

The detection output of the load detector 50 is input to the tension calculator 62, and the tension T of the rolled material 30 is determined.

The obtained tension T is added to the tension setting value Tre by the adder/subtractor 63.
A comparison operation is performed with f', and the deviation T is obtained.

A coefficient unit 64 multiplies this deviation ΔT by a coefficient KTV to provide an input to a control valve regulator 650. The control valve regulator 65 adjusts the opening degree of the control valve 58 according to the human power signal, and the fluid bad 5
7 to control the amount of fluid injected. That is, if the detected tension T is smaller than the tension setting value T, the control valve 5
8 to increase the amount of fluid ref' and increase the tension. Conversely, if the detected tension T is greater than the tension set value T, the control valve 58 is throttled to reduce the fluid volume and reduce the tension.

In this way, the tension applied to the rolled material 30 is controlled by the pressure of the fluid film, and the deviation ΔT becomes zero.

In addition, also in the case of FIG. 8, a load detector may be attached to the bearing of the presser roll, and control may be performed based on the detected output.

(Embodiment 4) FIG. 9 shows an example in which the tension control device 100 uses the attraction force of the electromagnet 101, and the rolling material is limited to ferromagnetic materials such as iron. Components with the same numbers as in FIG. 8 have the same functions as explained in FIG. 103 is an electromagnet output regulator. Detected tension T and tension setting value T. Tension control is performed by driving the electromagnet 101 according to the deviation ΔT from 1 to generate a vertical suction force on the rolled material 30. Note that the material of the electromagnet 10 is limited to electrically conductive materials.

By the way, earlier, in connection with FIG. 3, FIG. 4, FIG. 5, and FIG. 16, it was stated that the response of plate thickness control can be improved by increasing the response of tension control. The function of the tension control device of the present invention will be clarified.

FIG. 10 is a diagram illustrating the principle of the tension control device for the unwinding and winding reels 20°27.

Now, measure the diameter of the coil 67 and set the tension to the T1 motor 19 (
28) Letting the torque of τ be τ, the torque τ required to generate tension T when the coil diameter is small is proportional to the product of the coil diameter and tension T, and can be expressed as τocT −D (1) . On the other hand, the output torque of motor 19 (28) is ToCt・φ
(2), so from equations (1) and (2), To
Ct (φ/D) (3) is obtained.

i represents the motor current, and φ represents the motor field magnetic flux. Here, if the coil radius and the motor field magnetic flux φ are controlled to be proportional, (φ/D) becomes constant, and the tension T is proportional to the motor current i. From this, the tension control of the reel 20.27 is performed by making the coil diameter proportional to the motor field magnetic flux φ, and then setting the motor current to obtain the necessary tension T.
This is what you get. The above is the method for controlling the tension of the unwinding and take-up reels 20.27 during steady rolling (in a state where the rolling speed after acceleration is constant).

As shown in Fig. 16, in such a conventional tension control method, even if the roll gap is changed, the response of the tension control is slow, so the thickness of the exit side plate changes only by the response time of the tension control.
Therefore, even if a high-speed hydraulic reduction device was used, the plate thickness accuracy could not be improved.

FIG. 11 is a Bode diagram showing the effect on the exit side plate thickness Δh when the roll gap ΔS is changed. The dotted line shows an example in which a conventional tension control device is used, and the solid line shows an example in which the tension control device of the present invention (for example, 48 (FIG. 7)) is installed at the entrance side of the rolling mill. In the conventional example shown by the dotted line, the influence of the roll gap ΔS attenuates to 1/1000 at 3.75 Hz. This sharp downward peak will be explained later, but reel 20 (
This is caused by the resonance created by the inertia of 27) and the spring constant of the rolled material 30. On the other hand, in the device of the present invention shown by the solid line, the downward peak is shifted to the lower frequency side, and the attenuation at the peak is reduced to about 1/10. Furthermore, it can be seen that in the frequency range of 2 to 10 Hz, which we are currently focusing on, the characteristics become completely flat, and the roll gap ΔS is reflected in the plate thickness Δh.

FIG. 12 is a block diagram for explaining the functions of the tension control device of the present invention, and the control device portion is omitted because the response is quick. The dotted line represents the characteristics of the tension control device of the present invention.

The symbols are E: Young's modulus of the rolling mill, b: plate width, H: plate thickness,
L: Distance between rolling mill and reel, J: Moment of inertia of reel including coil, R: Coil radius (-D/2), K
t: gain of tension control device, S... Laplace operator, ΔV: rolling speed variation, ΔTb: rear tension variation.

The concept of this block diagram will be explained below. First, the reel 20 (27) including the coil 67 is accelerated by a tension value Tb proportional to the motor current value from a current control device (not shown), and a reel circumferential speed V is generated (block 69). This disturbance to the reel circumferential speed ■ is a speed change ΔV of the rolled material 30 caused by tension fluctuations on the entrance and exit sides of the rolling mill 32 and thickness fluctuations of the rolling mill 30. It becomes a balance. This is integrated by 73 and becomes the elongation difference Δg of the rolled material 30 in the longitudinal direction. In block 76, the change in tensile stress Δσ is calculated from the longitudinal elongation difference Δg.
is calculated and multiplied by bH to obtain the rear tension fluctuation ΔTb. It is compared with the tension value Tb by an adder 80, and its deviation T
The reel 20 (27) is driven at b-ΔTb, and the effect of ΔV is corrected by the process described so far. however,
Due to the large inertia of reel 20 (27), indicated by block 69, the speed of correction is slow as described above. The tension control device (for example, 48) of the present invention detects the tension fluctuation ΔTb, multiplies it by the conversion coefficient shown in block 82 to convert it into elongation change ΔI)r, multiplies it by the control gain Kt to obtain the control amount ΔOc, and calculates the tension. As can be seen from FIG. 12, since the inertia of the reel (block 69) is not involved, the response is faster.

If the transfer function from Δ■ to ΔTb is determined from FIG. 12 without considering the characteristics within the dotted line, the following equation is obtained.

From equation (5), the resonance frequency ω is determined as n, and in the conventional device shown by the dotted line in FIG. 11, this value was 3.75 Hz.

Next, Δ
The transfer function from V to ΔTb is expressed by the following equation, where G represents the dynamic characteristics of the tension control device, and is changed to block 86 in FIG. 12. That is, the tension control device of the present invention works to control the Young's modulus of the rolled material 30, and as a result,
Inertia of reel 20 (27) and spring constant of rolled material 30 (
It can be seen that it has the function of shifting the resonant frequency ω created by Young's modulus to a region that does not affect plate thickness control. Setting Kt to a positive value corresponds to shifting the resonance frequency to a lower frequency side than the actual resonance frequency, and setting Kt to a negative value corresponds to shifting it to a higher frequency side. By doing so, it is possible to prevent the phenomenon in which the tension is large due to the resonance of the reel 20 (27) and the runout plate thickness does not change even if the roll gap is moved at a high frequency, which occurs in the conventional control system.

The result of manipulating the roll gap will be reflected in the plate thickness, so Feed 2 Oward AGC and Bisla AG
Conventional plate thickness control methods such as C become effective.

(Example 5) An embodiment based on the above invention is shown in FIG.

As can be seen from equation (6), the inertia of the reel is the coil radius R
It changes as the changes. In Figure 13, the radius R
is detected by, for example, an optical sensor 90, based on which a correction amount ΔKt of the control gain Kt is determined by a calculator 91, and the control gain Kt is changed based on it.

(Embodiment 6) FIG. 14 shows another embodiment based on the above invention, in which the rolled material 3
Detect the velocity V of 0 with the detector 93, calculate the frequency of the entrance plate thickness disturbance based on it, and find the necessary ω, (6)
The control gain correction amount ΔK required to give it from the formula
The present invention is characterized in that the control gain Kt is changed by back calculating t using a calculator 94.

[Example of change]

In the above embodiments, only the case where the present invention is applied to a jingle stand cold reversible rolling mill is described. It goes without saying that the present invention can be applied to all rolling mills in which the problems described in the technical section occur.

Moreover, the tension can be detected by the reaction force from the rolled material applied to rolls and other members disposed in the travel path of the rolled material in addition to the presser roll and deflector roll.

〔Effect of the invention〕

As explained above, according to the present invention, since the tension control device is provided on the inlet side or both the inlet and outlet sides of the rolling mill,
Tension fluctuations at the entrance or exit side of the rolling mill that occur as a result of changing the rolling position of the rolling mill to control plate thickness can be quickly suppressed, speeding up the response of plate thickness control and producing highly accurate product plates. thickness can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the system configuration of a plate thickness control device for a cold reversible rolling mill to which the present invention is applied. FIG. 2 is a diagram showing a specific example of the tension control device 3334 in FIG. 1. Figures 3 to 5 are diagrams showing computer simulation results showing the response when the response of the filter motor tension control device 18 and 29 in the apparatus shown in Figure 15 is made three times faster.
The figure shows a case where both input and output side tension control devices 33 and 34 have a faster response, Figure 4 shows a case where only the output side tension control device 34 has a faster response, and Figure 5 shows a case where only the input side tension control device 33 has a faster response. This is the case. FIG. 6 is a block diagram showing another embodiment of the invention. FIG. 7 is a diagram showing a specific example of the tension control device 48°49 in FIG. 6. FIG. 8 is a diagram showing still another embodiment of the tension control device according to the present invention. FIG. 9 is a block diagram showing an embodiment of the present invention using an electromagnet or a linear motor as the tension control device. FIG. 10 is a diagram illustrating the principle of tension control of the unwinding and take-up reels 20°27. FIG. 11 is a Bode diagram showing the influence on the exit side plate thickness Δh when the roll gap ΔS is changed. FIG. 12 is a block diagram for explaining the functions of the tension control device of the present invention. FIG. 13 is a block diagram showing an embodiment of the present invention in which the control gain is modified according to the coil diameter. FIG. 14 is a block diagram showing an embodiment of the present invention in which the control gain is modified depending on the speed of the rolling mill. FIG. 15 is a block diagram showing the system configuration of a conventional plate thickness control device for a cold reversible rolling mill. FIG. 16 is a diagram showing simulation results showing the response of plate thickness control of the apparatus shown in FIG. 15. 6... Hydraulic cylinder (hydraulic cylinder), 8... Servo valve, 32... Rolling machine, 2o... Unwinding reel, 2
1... Deflector roll, 27... Take-up reel,
1928...Reel motor tension control (current control) device, 30...Rolled material (rolled material), 33.34,48
゜49.61... Tension control device, 35... Presser roll, 37.50... Load detector (tension detector), 57
...Fluid pad (fluid support mechanism), 66...Hydraulic pressure lowering device.

Claims (7)

[Claims] (1) A plate thickness control device for a rolling mill comprising a tension control device for adjusting the tension applied to a rolled material on the entry side or both the entry and exit sides of a rolling mill equipped with a hydraulic reduction device. (2) The tension control device includes a tension detector that detects the tension applied to the rolled material, a presser roll that presses the rolled material, and a hydraulic cylinder that drives the presser roll in the direction of the rolled material; The plate thickness control for a rolling mill according to claim 1, further comprising a servo valve that controls the flow rate to the hydraulic cylinder based on the difference between a predetermined tension setting value and the tension detected by the tension detector. Device. (3) The tension control device includes a tension detector that detects the tension applied to the rolled material, a fluid support mechanism that forms a fluid film that supports the rolled material, and a predetermined tension setting value and the tension. 2. The plate thickness control device for a rolling mill according to claim 1, further comprising a control valve that controls an output amount of the fluid support mechanism based on a difference between the tension and the tension detected by a detector. (4) The tension control device includes a tension detector that detects the tension applied to the rolled material, an electromagnet that can apply an attractive force or a repulsive force to the rolled material, or a linear magnet.
Claim comprising: a motor; and a regulator that controls the attractive force or repulsive force of the electromagnet or linear motor based on the difference between a predetermined tension setting value and the tension detected by the tension detector. 1. The plate thickness control device for a rolling mill according to 1. (5) A claim in which the tension detector comprises a load detector that detects a reaction force from the rolled material acting on the presser roll, deflector roll, or other roll or other member arranged in the running path of the rolled material. Item 5. A plate thickness control device for a rolling mill according to any one of items 2 to 4. (6) The rolling according to any one of claims 1 to 5, characterized in that the positive/negative sign and magnitude of the control gain of the tension control device are changed based on the measured diameter of the coil wound on the reel. Machine plate thickness control device. (7) The rolling mill plate according to any one of claims 1 to 5, wherein the sign and magnitude of the control gain of the tension control device are changed based on a signal from a speed detector of the rolling material. Thickness control device.