JPH0236323B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved speed control system for a reversing rolling mill.

Conventionally, a reversible rolling mill is generally composed of two tandem rolling mills, a first rolling mill and a second rolling mill, as shown in FIG. Since only light rolling is performed, the motor capacity of the first rolling mill is smaller than that of the second rolling mill. Therefore, when the first rolling mill and the second rolling mill are used in tandem, the effect of the difference in speed coordination between the first rolling mill and the second rolling mill is an increase or decrease in the motor current of the first rolling mill, which has a small motor capacity. It appears as.

That is, the speed of the second rolling mill 5b is given by the speed setting device 1, the speed control device 2b controls the output voltage of the power converter 3b, and the speed of the second rolling mill 5b becomes equal to that of the speed setting device 1. Yo electric motor 4b
change the speed of On the other hand, the speed of the first rolling mill is higher than the speed of the second rolling mill by the speed detection 6 of the second rolling mill.
By multiplying b by roll diameter correction 7 and draft 9 using multipliers 8 and 10, it is given as the speed setting of the first rolling mill. The first rolling mill 5a is
Similar to the rolling mill, the given speed setting is controlled by the speed control device 2a, power conversion device 3a, and electric motor 4a so that the speed of the first rolling mill 5a becomes equal.

Also, if the values of the roll diameter setting device 7 and draft setting device 9 are not set correctly and the material speed on the exit side of the first rolling mill is faster than the material speed on the entry side of the second rolling mill, the first rolling mill The material is then pushed through the material 15 into the second rolling mill. In such a case, the second rolling mill
Compared to a rolling mill, the electric motor capacity is generally larger, so the influence on the second rolling mill is small. However, since the first electric motor 4a controls the speed at the given speed setting, an overcurrent occurs, and the speed control device of the first rolling mill becomes uncontrollable, making rolling impossible.
Conversely, the same applies when the exit speed of the first rolling mill is lower than the inlet speed of the second rolling mill.

Therefore, in order to prevent such situations, generally,
A current detector 12 detects the current of the electric motor 4a of the first rolling mill.
a, and adder 14 adds this to the speed setting.
When the current increases due to material pushing, the speed of the first motor is reduced. Further, even when the material is pulled and rolled in the first rolling mill, the material is similarly fed back to the adder 14a of the first rolling mill so as to increase the speed of the electric motor of the first rolling mill. This gives the speed control device 2a a drooping characteristic and prevents the speed from becoming uncontrollable.

However, if there are two or more rolling mills that perform heavy reduction,
When tandem rolling is performed using rolling equipment in which each rolling mill has its own drooping characteristic, if the speed of one rolling mill is corrected due to a difference in speed coordination between the two rolling mills, the coordination of the other rolling mills will be changed through the material. The speeds of rolling mills that are out of range will also be corrected in sequence. Therefore, since the material is repeatedly pushed or pulled each time, it takes a long settling time to complete quality and speed corrections to the material, making smooth rolling impossible.

The present invention has been made in view of the above-mentioned reasons, and an object of the present invention is to provide a speed control device for a reversible rolling mill that does not have the above-mentioned drawbacks and can perform rolling smoothly without the speed control device becoming uncontrollable.

The present invention will be explained below with reference to the drawings. FIG. 2 shows an embodiment of the present invention, and since the same reference numerals as in FIG. 1 are the same, the explanation will be omitted. In this embodiment, a tandem rolling mill composed of three rolling mills will be described. Generally, when rolling mills of the same capacity are configured in tandem, the overall rolling line speed is set by the speed setting device 1, and the speed of each rolling mill is determined by taking into account the reduction amount of the rolling mill, roll diameter, gear ratio, etc. , are set by speed regulators 16a, 16b, and 16c of each rolling mill so that the speeds of the rolling mills are harmonized. Therefore, for the speed setting of each rolling mill, the multiplied value of the speed setter 1 and the speed regulators 16a, 16b, and 16c is given as a speed reference signal. Speed control devices 2a, 2b, 2c for each rolling mill
The power converters 3a, 3b, 3c are connected so that the given speed reference signal and the speed of each rolling mill are equal to each other.
It is controlled by controlling the output voltage of the motors 4a, 4b, and 4c and changing the speeds of the motors 4a, 4b, and 4c.

On the other hand, the current of each motor is detected by a current detector 12a,
12b and 12c, respectively, through load regulators 13a, 13b, and 13c, which convert the signals into speed correction signals for the second rolling mill 5b and third rolling mill 5c,
It is applied to adders 14b and 14c.

That is, if now, during forward pass rolling, the speed setting of the first rolling mill is compared to the rolling speed of the second and subsequent rolling mills,
When set at a high speed, the first mill exerts a pushing force on the second mill through the material 15. As a result, the motor current of the first rolling mill increases, and this motor current is detected by the current detection 12a. The increased motor current is transmitted as a speed correction signal for the second and subsequent rolling mills by polarity switching 17 via a load regulator 13a determined from the rolling torque of each rolling mill, motor torque, speed setting of each rolling mill, etc. output, and increases the speed of the second and subsequent rolling mills to coordinate with the first rolling mill. Furthermore, if the n-th rolling mill is the second rolling mill, similarly when the motor speed of the second rolling mill is high, the speed correction signal of the load regulator 13b is different from the speed correction signal of the first rolling mill. , are added by the adder 18b. Here, n is a natural number of 1 or more. Then, the speed of the third rolling mill, which is the n+1st rolling mill, is increased, and the speed of the first rolling mill,
Coordinate with the second rolling mill. On the other hand, during reverse pass rolling, for example, if the n-th rolling mill is the third rolling mill, the speed correction of the third rolling mill is given to the second and first rolling mills to achieve coordination. In this embodiment, a tandem rolling mill constituted by three rolling mills has been described, but the same applies to three or more rolling mills.

In this way, according to the present invention, speed coordination among the rolling mills can be achieved, and rolling can be carried out smoothly.
An effective speed control device for a reversible rolling mill can be provided.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a conventional reversible rolling equipment, and FIG. 2 is a block diagram showing an embodiment of the present invention. 1...Speed setter, 2a, 2b, 2c...Speed control device, 3a, 3b, 3c...Power converter, 4
a, 4b, 4c... electric motor, 5a, 5b, 5c...
...First, second, third rolling mills, 6a, 6b, 6c...
...Speed detector, 7...Roll diameter setting device, 8,10
... Multiplier, 9 ... Draft setting device, 12a, 1
2b, 12c... Current detector, 13a, 13b,
13c...Load adjuster, 14a, 14b, 14
c, 18b, 18c, 19b, 19c... Adder, 15... Material, 16a, 16b, 16c...
Speed regulator, 17...Polarity switch.

Claims (1)

[Scope of Claims] 1. A reversible rolling facility in which a plurality of rolling mills are each controlled by an independent speed control device and perform tandem rolling based on a speed reference signal that sets the rolling line speed of the plurality of rolling mills, a speed control device that controls a power converter in each rolling mill based on the speed reference signal; a motor that changes the rolling mill speed based on the output voltage of the power converter; a current detector that detects the motor current; and a load adjuster that corrects the speed reference signal given to the speed control device of the other rolling mills with a speed correction signal based on the current value detected by the current detector and its polarity, and during forward rotation, the plurality of rolling mills The first rolling mill is provided with a device that continuously detects increases and decreases in the motor current of the first rolling mill of the mill, and increases and decreases the speed of the second and subsequent rolling mills via the load regulator. The rolling mill is continuously controlled by a speed correction signal from the load regulator provided in the rolling mill, and the n+1th rolling mill is controlled by the speed correction signal from the load regulator provided at the nth (n is a natural number of 1 or more) rolling mill. The speed increase and deceleration of the rolling mills after the 1st rolling mill are controlled, and in the case of reverse operation, the speed correction signal from the load regulator provided in the nth rolling mill is used to control the speed correction signal of the
-2, . . . A speed control device for a reversible rolling mill, characterized in that it controls speed increase and deceleration of a second and a first rolling mill.