JPS6335326B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a load balance control device for a reversing rolling mill.

Generally, load balance control is used to mutually control the torque between the upper and lower rolls in reversible rolling mill mill motors, etc. By eliminating torque imbalance and balancing the loads of the upper and lower motors, the rated mill capacity can be increased. It is used for the purpose of making full use of it. Further, this load balance control is preferable for the motor itself in terms of aging deterioration, life span, and maintenance.

Load balance control in such a reversible rolling mill is used to mutually control the torque between the upper roll and the lower roll, and balancing the loads of the upper and lower motors on the rolling mill ensures full capacity. However, if there is a difference in temperature or deformation resistance between the front and back surfaces of the rolling mill, the current load balance control is difficult to control during rolling operations, especially against sheet warping. This may cause some inconvenience. In _other words, when the diameter of the upper roll 1 is smaller than the diameter of the lower roll ₂ as shown in FIG. Assuming that the rotation speed of the rolls is the same and the rolls are bitten, the projected contact arc length l ₂ of the lower roll 2 is
Since l is larger than ₁ , the deformation speed of lower roll 2 (back side of the rolling mill) is faster. Therefore, the rolled material becomes warped. However, due to load balance control, the lower roll 2
Since the rotation speed can be lowered, there is no problem. However, as shown in Fig. 2, the diameter of the upper roll 1 and the lower roll 2
The diameter of is the projected contact arc length of the upper and lower rolls shown in the diagram.
If l ₁ and l ₂ are both equal and the rolling mill temperature is lower on the back side than on the front side, or if the front deformation resistance is lower than the back side deformation resistance, the front side deforms more easily and the deformation speed is faster. , the upper roll load becomes smaller than the lower roll load. Therefore, in this state, even though the rolling mill warps downward, the load balance control determines that the load on the lower roll is large and lowers the rotational speed of the lower roll 2, thereby promoting the downward warping. If there is a difference in temperature or deformation resistance between the front and back surfaces of the rolling mill as described above, load balance control may be inconvenient in the rolling operation.

For such correction of sheet warpage during rolling, the third
As shown in the figure, a method based on roll diameter compensation is used. That is, in the figure, an upper roll thyristor device 12 is connected to the upper roll drive motor 10, and an upper roll voltage controller 14 is connected to this upper roll thyristor device 12. An upper roll current controller 16 is connected to this upper roll voltage controller 14, and an upper roll speed controller 18 is connected to this upper roll current controller 16. One input terminal of the upper roll speed controller 18 is configured to receive a reference voltage V via a roll system compensator 20, and the other input terminal of the upper roll speed controller 18 is connected to a load balancer, which will be described later. The output terminal of the dead band amplifier 25 of the control circuit 21 is connected. The upper roll speed controller 18 is for setting the speed of the upper roll (not shown), and outputs a signal corresponding to the set value to the upper roll current controller 16. The upper roll current controller 16 receives a signal from the upper roll speed controller 18 and outputs a corresponding current value to the upper roll voltage controller 14. The corresponding voltage value is output to the upper roll thyristor device 12. The upper roll thyristor device 12 converts the output voltage value from the upper roll voltage controller 14 into a pulse signal corresponding to the output voltage value, and opens and closes the gates of each thyristor of the thyristor device depending on the on-duty of the pulse signal. The upper roll drive motor 10 is driven by the conduction of the upper roll thyristor device 12.

On the other hand, a lower roll thyristor device 13 is connected to the lower roll drive motor 11, and a lower roll voltage controller 15 is connected to this lower roll thyristor device 13. This lower roll voltage controller 15 includes a lower roll current controller 1.
7 is connected to the lower roll current controller 17, and a lower roll speed controller 19 is connected to the lower roll current controller 17. This lower roll speed controller 1
9 is configured so that a reference voltage is input to one input terminal, and an output signal from an inverting amplifier 26 of a load balance control circuit 21 to be described later is input to the other input terminal. This lower roll speed controller 19 also has the same function as the above-mentioned upper roll speed controller 18, and the lower roll current controller 17, lower roll voltage controller 15, lower roll thyristor device 13, and lower roll drive motor 11 are connected to the upper roll speed controller 18, respectively. It has the same functions as the roll current controller 16, the upper roll voltage controller 14, the upper roll thyristor device 12, and the upper roll drive motor 10, respectively.

Further, an input terminal of an inverting amplifier 22 of a load balance control circuit 21 is connected to an output terminal a of the upper roll speed controller 18. The input terminal of a comparison amplifier 23 is connected to the output terminal of the inverting amplifier 22. The output terminal b of the lower roll speed controller 19 is connected to the other input terminal of the comparison amplifier 23.
A limiting amplifier 24 is connected to the output terminal of the limiting amplifier 24, and a dead band amplifier 25 is connected to the output terminal of the limiting amplifier 24.
is connected. An inverting amplifier 26 and the upper roll speed controller 18 are connected to the output terminal of the dead band amplifier 25. Inverting amplifier 26
The output terminal of the lower roll speed controller 19
is connected to the input terminal of In this way, the load balance control circuit 21 is configured by the inverting amplifier 22, the comparison amplifier 23, the limiting amplifier 24, the dead band amplifier 25, and the inverting amplifier 26.

Therefore, the upper roll drive motor 10 and the lower roll drive motor 11 have the same reference voltage.
rotates at the same speed given through 3. now,
The output value of the upper roll speed controller 18 and the lower roll speed controller 19, that is, the current command (a, b in the figure) is input to the load balance control circuit 21. The current command for the upper roll is inverted by the inverting amplifier 22, and the current command for the lower roll is inputted as is to the comparator amplifier 23, where the upper and lower current command values are compared and the deviation is calculated. It is output to the limiting amplifier 24.
In this limiting amplifier 24, an upper limiter value is set, and in a deadband amplifier 25, a lower limit value limiter cuts off the deadband value (variable setting is possible). One of these outputs is directly fed back to the upper roll speed controller 18, and the other is inverted. The polarity of the signal is inverted via the amplifier 26 and input to the lower roll speed controller 19 .

A load balance control circuit has a function of balancing the loads of the upper and lower roll drive motors using the flow of such analog signals.

On the other hand, the roll system compensator 20 varies the reference voltage for the upper roll drive motor 10, and by changing the reference voltage by α by ±α and applying a voltage by (+) α or minus α, the lower roll is driven. The speed of the upper roll drive motor changes by the voltage difference α with the motor 11 as a reference.

However, for example, when it is desired to drive the lower roll drive motor 11 at a slightly faster speed as a countermeasure against upward warping, the voltage +α is applied to the upper roll speed controller 1.
8, the upper roll speed controller 18
The output also has a value changed by (+)α. Therefore, the load balance control circuit 21 receives the output value +α from the upper roll speed controller 18 as an input value and performs load balance control, and the upper roll speed controller 18 is commanded to lower and the lower roll speed controller 19 is commanded to raise. are input respectively. As a result, the roll system compensator 2
Despite the command to increase the speed of the upper roll drive motor 10 by 0, the load balance control circuit 21
This has the drawback that a signal to match the reference voltage is fed back, rendering the functional effect of the roll system compensator 20 completely meaningless, and making it impossible to correct the warpage of the rolled plate at all.

The purpose of the present invention is to
To provide a load balance control device for a reversible rolling mill capable of correcting sheet warpage by temporarily allocating the load to either the upper or lower rolls.

The present invention arbitrarily sets a load balance dead zone area from the outside, detects the occurrence of unbalance within the arbitrarily set dead zone area, and then detects that the load factor of the drive motor at the time of unbalance falls within the allowable range. If the load is not exceeded, the load balance control is stopped and the load is temporarily shared between the upper and lower rolls in order to correct the warping of the board.

Examples of the present invention will be described below.

FIG. 4 shows an embodiment of a load balance control device for a reversible rolling mill according to the present invention.

In the drawings, the same reference numerals as in the conventional example shown in FIG. 3 indicate the same parts and the same functions. Upper roll speed controller 18
A load balance control circuit 100 is connected to the output terminal of the load balance control circuit 10.
0 is connected to a load balance dead zone control circuit 101. Also, the load balance control circuit 10
0 is configured to receive an output signal from the lower roll speed controller 19. Further, a contact 111 is provided at the two output terminals of the load balance dead zone control circuit 101, and the other end of this contact 111 is connected to the upper roll speed controller 18.
The input terminal of the lower roll speed controller 19 is connected to the input terminal of the lower roll speed controller 19, respectively. This contact point 11
1 operates in conjunction with each other.

On the other hand, a load factor meter 110 is provided that detects the load factor based on the motor current of each of the upper roll drive motor 10 and the lower roll drive motor 11. It detects the ratio to the allowable current flowing through the drive motor 11, and has a function of outputting an alarm signal to the alarm 113 connected to the load factor meter 110 when the allowable current is exceeded. The load factor meter 110 also detects the load factors of the upper roll drive motor 10 and the lower roll drive motor 11 and outputs them to the AND circuit 105. An AND circuit 104 is connected to the other input terminal of this AND circuit 105.
A load balance dead zone detector 103 is connected to one input terminal of the circuit 104 . This load balance dead zone detector 103 detects the load balance control dead zone output from the load balance dead zone control circuit 101, and is connected to the load balance dead zone setting device 102,
It compares it with the set dead zone from the load balance control dead zone setting device 102 and outputs the deviation. The load balance control dead zone setting device 102 changes the area of the load balance dead zone, and is installed so that it can be remotely controlled from the outside. Moreover, this load balance control dead band setting device 102 is composed of a variable resistor, and is comprised of a variable resistor from 0 to
It has a structure that can be set arbitrarily to 100%.

On the other hand, the other input terminal of the AND circuit 104 is connected to a load balance control switch 112A. The output terminal of the AND circuit 105 is connected to a set/reset signal generator 106, and the input terminal of the set/reset signal generator 106 is connected to the output terminal of the OR circuit. A load cell 109 is connected to one input terminal of this OR circuit 107 via a timer circuit 108. This load cell 109 is used to confirm that the rolled material has been ejected from the mill, and when it detects that the rolled material has been ejected from the mill, it outputs a metal-off signal to the timer circuit 108. This timer circuit 108 is used to stop outputting the output signal from the load cell to the OR circuit 107 for a predetermined period of time. This is to prevent chattering of the load cell 109 and erroneous detection. Further, a load balance control switch 112B is connected to the other input terminal of the OR circuit 107. This load balance control switch 112B
is interlocked with the load balance control switch 112A, and the load balance control switch 112A
When turned on, load balance control switch 112B
is operated to turn off.

The output terminal of the set/reset signal generator 106 is connected to the contact 111.
1 has a function of turning ON with a set signal from the set/reset signal generator 106 and turning OFF with a reset signal.

Since the device is constructed in this way, the state of warpage of the rolling equipment is judged and the set value of the load balance control dead band setter 102 is set to an arbitrary percentage, and at the same time, the load balance control switch 112A is turned on. The load balance dead zone area is determined based on the settings of the load balance control dead zone setting device 102, and the load balance dead zone detector 103 determines the unbalance amount between the load of the upper roll drive motor and the load of the lower roll drive motor to set the load balance control dead zone. 102 and outputs the signal to AND circuit 1.
04 and is set by ANDing with the ON signal of the load balance control switch 112A.
A reset signal is output from the reset signal generator 106. This set/reset signal generator 10
The contact 111 connected to the output terminal of the load balance dead zone control circuit 101 is turned off by the reset signal output from the load balance dead zone control circuit 101. The condition for the reset signal output from the set/reset signal generator 106 is that the alarm output of the load factor meter 110 is
OFF (within the set percentage), that is, when the output from the load factor meter 110 is OFF.

On the other hand, the conditions for outputting the set signal from the set/reset signal generator 106 are when the load balance control switch 112B is turned off in conjunction with the load balance control switch 112A, or when it is detected that the rolled material has bitten the mill. The timer circuit 10 receives the metal-off signal from the load cell 109.
This is when the output is performed after a predetermined time of 8.

Therefore, according to this embodiment, the effect of the roll system compensator, which is effective in correcting sheet warpage, is increased, and by allowing the operator of the rolling mill to set the dead zone area as desired, When used in common with a roll compensator, measures can be taken depending on the rolled material and the situation, improving efficiency and quality.

In addition, according to this embodiment, in the conventional load balance control circuit, the adjustment of the dead zone was built into the card of the device and was used as a nearly constant value, but by making it possible to perform it remotely from the outside, the load balance dead zone can be detected. The load balance condition within the range set by the load balance control dead band setting device 102 can be confirmed by the device, and when the load balance control circuit is disconnected, rolling operations can be performed without the need to constantly check the current difference between the upper and lower loads. .

Furthermore, according to this embodiment, since the load balance control circuit itself can be arbitrarily varied or the load balance control circuit can be turned off, board warpage can be easily corrected by the speed difference between the upper and lower rolls using the roll system compensator. Can be done.

As explained above, according to the present invention, if a warpage occurs during rolling, the warpage can be corrected by temporarily distributing the load to one of the upper and lower rolls.

[Brief explanation of the drawing]

Figure 1 shows the rolling situation when the upper roll and lower roll of the rolling machine have different diameters, and Figure 2 shows the rolling situation when the upper roll and lower roll of the rolling machine have the same diameter, and the surface of the rolled material is high temperature and the back side is FIG. 3 is a circuit diagram showing a conventional load balance control device for a reversing rolling mill, and FIG. 4 is a circuit diagram showing an embodiment of the present invention. 100... Load balance control circuit, 101... Load balance dead zone control circuit, 102... Load balance control dead zone setting device, 103... Load balance dead zone detector, 104, 105... AND circuit,
106...Set/reset signal generator, 107...
OR circuit, 108...Timer circuit, 109...Load cell, 110...Load factor meter, 111...Contact, 112
A, 112B...Load balance control switch.

Claims (1)

[Claims] 1. In a load balance control device for a reversible rolling mill that balances the load of the upper roll drive motor and the load of the lower roll drive motor and mutually controls the torque between the upper roll and lower roll, the load of the upper roll drive motor and the load of the lower roll are balanced. a first means for externally arbitrarily setting a dead zone region in which the load balance control operation is stopped when the amount of unbalance with the load of the roll drive motor is within a predetermined range; a second means for detecting that it is within a dead zone region arbitrarily set by the first means; and a third means for detecting that the load factor of the vertical roll drive motor is within a set allowable load factor. A load balance control device for a reversible rolling mill, characterized in that the load is temporarily shared between the upper roll and the lower roll in the dead zone region.