JPS585726B2 - Upper and lower roll load balancing circuit in a rolling mill - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a circuit for balancing loads on upper and lower rolls in a high-speed rolling mill.

Conventionally, in rolling mills that drive the upper and lower rolls separately,
In order to prevent various problems caused by unbalanced loads on the upper and lower rolls, a circuit is provided to balance the loads on the upper and lower rolls.

However, in conventional upper and lower roll load balancing circuits, a current detection device that detects the main circuit current is used for feedback, resulting in a large voltage level difference within the circuit, and as an insulation measure, an isolation amplifier, etc. is used. The circuit is complicated, and the response time of the control system is slow.
Since there is a delay of about 0.1 to 0.2 seconds, in a high-speed rolling mill, the length of the steel plate that runs during that time, about 2 to 4 meters, cannot be ignored.

In addition, in the past, the load balance control signal was applied directly to the roll speed control device, so the magnitude of the load balance control signal output was constant regardless of the roll speed. There was a drawback that the magnitude of the load balance control signal was larger than the magnitude of the signal, causing problems in speed control such as roll reversal.

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the above-mentioned drawbacks and to provide an upper and lower roll load balancing circuit which is quick in response, highly reliable, and in which the load balancing control signal is adjusted proportionally to the roll speed.

The upper and lower roll load balancing circuit according to the present invention eliminates the signal level difference in the circuit by using the speed deviation signal for roll speed control for its feedback, and eliminates the shunt resistor, isolation amplifier, etc. that were conventionally required. The error and delay of the signal are practically set to zero, and the load balance control signal obtained by comparing the above-mentioned upper and lower roll speed deviation signals by a comparator and the roll speed signal obtained from a speed detector such as a tacho generator, etc. By multiplying by a multiplier, the load balance control signal is changed proportionally according to the roll speed, thereby enabling stable speed control from low speed (approximately 200 m/min) to high speed (approximately 1500 m/min). It is something.

A conventional load balancing circuit and a load balancing circuit according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an example of a conventional upper and lower roll load balancing circuit.

In the figure, numerals 1 and 2 are drive devices for the upper and lower rolls, respectively, and include a DC motor, a motor generator, a thyristor Leonard, and others.

Reference numerals 3 and 4 are control devices for the drive device, which include a phase controller and other devices.

Adders 5 and 6 add the speed deviation signal and the motor load detection signal fed back from 1 and 2 with appropriate weighting, respectively, and supply motor control reference signals to the control devices 3 and 4.

7 and 8 are also adders, which receive the roll speed detection signals from the tacho generators 9 and 10, the rolling mill speed setting signal from the rolling mill speed setting device 11, and the comparison adder 12.
and the upper and lower roll load balance comparison signals given directly or through the inverter 13 from the above with appropriate weighting, and a speed deviation signal is supplied to the devices 5 and 6 above.

Reference numerals 15 and 16 are isolation amplifiers which input the motor load signals fed back from the roll drive devices 1 and 2, respectively, through an inverter 14 or directly to a comparison adder 1.
Supply to 2.

Next, FIG. 2 is a block diagram showing an example of an upper and lower roll load balancing circuit according to the present invention.

In the figure, blocks with the same numbers as in Figure 1 are
Since the apparatus shown in FIG. 1 is similar to that shown in FIG. 1, the differences between the two will be explained.

In the device according to the invention, the isolation amplifiers 15 and 16 in the conventional device as shown in FIG.
through which the other one directly receives and generates an upper and lower roll load balance comparison signal.

This signal is applied to a multiplier 19, where it is multiplied by the roll speed detection signal from the tacho generator 9 and then supplied to adders 7 and 8, respectively.

Reference numerals 17 and 18 are setting devices for adjusting the upper and lower roll speeds, respectively, when an unbalance exceeding the range that can be controlled by the device of the present invention occurs (roll diameter,
(by changing the material, etc.), increasing the reliability and availability of the rolling mill.

As is clear from the above explanation, the feedback signal of the load balancing circuit is extracted from inside the control circuit and separated from the main motor circuit, and the load balancing signal to the upper and lower rolls is made proportional to the roll speed signal. By adding adjustment setting devices to each of the upper and lower roll drive control circuits, response speed and accuracy are significantly improved compared to conventional load balancing circuits, providing a rolling mill that is stable, reliable, and highly available from low to high speeds. I was able to do that.

This prevents roll seizure accidents and strip flattening accidents due to load imbalance in, for example, cold rolling and temper rolling mills, thereby improving productivity and quality.

It goes without saying that the present invention can produce similar effects even when used in upper and lower roll load balancing circuits of various rolling mills.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an example of a conventional upper and lower roll load balancing circuit, and FIG. 2 is a block diagram showing an actual example of the upper and lower roll load balancing circuit according to the present invention. 1, 2... Roll drive device, 3, 4...
・Control device, 5, 6, 7, 8...Adder, 9,
10...Tacho generator, 11...1...Rolling mill speed setting device, 12...Adder for comparison, 1
3,14... Inverter, 15.16...
Insulation amplifier, 17, 18... Roll speed adjustment setting device, 19... Multiplier.

Claims (1)

[Claims] 1 Upper and lower roll load balancing circuit in a rolling mill,
a comparison device for obtaining a load balance control signal by comparing speed deviation signals in each of upper and lower roll speed control feedback circuits of a rolling mill; and a comparison device for obtaining a load balance control signal and a roll speed signal obtained from the load balance control signal and the feedback circuit. 1. A load balancing circuit comprising: a multiplication device for multiplication, and applying the multiplied load balancing signal to an adding circuit for generating a speed deviation signal in each of the upper and lower feedback circuits.