SU937069A1 - Apparatus for reducing slippage between rolling rolls and back-up rolls of sheet rolling mills - Google Patents

Description

. . G.

The invention relates to the automatic control of rolling metals on reversible sheet mills. Quarto.

A device for regulating, nor the acceleration of, the rolling mill rolls, comprising a motor for rotating work rolls, speed sensors for supporting and working rolls, and a block of differentiators, the input of a speed sensor for rotation of work rolls and the outputs for speed sensors for rotating and roll working rolls are connected to the inputs of the block of differentiators pj.,

A disadvantage of the known device is the use as the main actuator for leveling the speeds of the drums. rolls, during the period of slippings, the main drive of the work rolls, which has a low on large mills with acceleration control

speed due to large iahovyh masses drive line cage. This does not allow for the acceleration or deceleration of the rolls with large accelerations, which on reversing mills significantly reduces their productivity. In addition, this device does not affect the main nepBonpHMH to slip - the dynamic moment of the support roll, which creates a force that counteracts the friction force (cohesion) between the work roll and the support roll. Since the strength of the friction between the rollers depends on the efforts of their pressing, due to the constructive mills

Since the performance of the work roll balancing systems, and the counteracting force depends on the fly weight of the support roll and the magnitude of its acceleration, there always exists a limiting acceleration value, above which slip begins. The values of these accelerations are low on mills that have small values of the coefficient of friction at the point of contact between workers and support rolls, which reduce the strength of their adhesion. For example, in the case of hot rolling aluminum cushions due to the misalignment of work rolls and the use of emulsion with organic fat for cooling the rolls, the values of the coefficient of friction are / 0.025 + 0.08. The aim of the invention is to increase the productivity of the mill with increased acceleration and deceleration of the rolls by providing acceleration and stopping the rolls of the rolling stand while maintaining load bearing capacity of the work rolls. This goal is achieved by the fact that the device for reducing the slip between the working and supporting rolls of SHEET mills, containing an electric motor of rotation of the work rolls, speed sensors of rotation of the support and work rolls and a differential block, and the input of the speed sensor is rotary. The working rolls are connected to the rotational motor of the working rolls, and the outputs of the rotational speed sensors of the reference and working rolls are connected to the inputs of the differentiator unit, additionally contains a task unit, a pulse comparison unit from the differentiated signals of the rotational speed sensors of the reference and work rolls a motor-pump, a pumping unit with an engine and a pumping unit capacity controller, the input of the task unit connected to the electric motor work rolls, the output of the task block is connected to the first input of the adder, the second input of which is connected to the output of the pulse comparison unit from the differentiated signals of the speed sensors of the main and working rolls, the first and second inputs of which are connected to the outputs of the block of differentiators, the output of the adder to the inlet of the productivity regulator of the pumping unit, the output of which is connected to the engine of the pump unit, and the supporting eajloK is rigidly connected to the shaft of the reversible hydraulic machine by a pump-driven motor pump installation. The drawing shows a diagram of the proposed device. 93 94 The diagram shows supporting 1 and working 2 rolls, electric motor 3 for rotating work rolls, reversible hydraulic machine 4, pump installation 5 and motor 6 for a pump setting regulating the rotation speed of the supporting and working rolls, tachogenerators 7, safety 8 and check valve 9, reservoir 10, task block 11, block 12 diff; Ratio, unit 13 comparison of the pulses of differentiated signals from the speed sensor of the support and work rolls, the accumulator of 1 signals, the controller 15 of the performance of the pumping unit. The device works as follows. When the stand is started up on the task unit, the predicted effect signal is set as a function of acceleration and the ground mass of the support roll with a duration until reaching the specified idling speed step. The signal through the adder 14 enters the regulator 15, which adjusts the pumping unit 5 with the electric motor 6 to a capacity that enables the motor pump L to create a predetermined torque and applied in the direction of rotation of the support roll. At the same time, signals from tachogenerators 7 are fed to block 12 of differentiators, where their differentiated deviation is compared with a predetermined value depending on the actual roll diameters and the corresponding equal speeds of the roll barrels. If the ratio of differentiated signals does not match the setpoint, then the adder k passes the pulse of the difference between the actual and set deviations, which is summed with the signal from the task unit 11, and through the controller 15 increases the performance of the pump unit (engine speed 6) proportional to the signal increment. Since the duration of the impact roller is set to a desired speed by the rolling engine at idle, and with the working load of the cage, a predetermined speed decrease occurs (speed drawdown), this provides a leading effect on the support roll during rolling. The driver ensures that this effect is preserved even if it is slowing down.

This is necessary in order to provide a preventive effect on the support block during the period of ejection of the roll out of the rolls when the speed reduced under the working load (speed decrease of the main drive) of the rolls tends to sharply reach the set value, creating the most favorable conditions for the slip.

The possibility of such a leading effect is due to the fact that under a working load on the stand, the force of adhesion of the rolls is immeasurably greater compared with the opposing force from the dynamic moment of the support roll.

During deceleration at idle, the driver changes the direction of the applied action on the opposite rotation of the roll, and the comparison unit reverses the differential ratio of the signals coming from the speed sensors, and compares it with the correspondingly changed predetermined ratio.

The proposed device is of particular importance for large quarto reversing mills with a barrel length of 2500-5000 mm, where the support rolls have significant moving masses that contribute to slippage. The use of this device makes it possible to perform rolling with high accelerations under relatively low conditions of pressing the working and cone rolls, which provides mills with high productivity, rolling in a narrow temperature range and reduces the cools of the ends of the strips due to the reduced contact time between the rolled metal and the work rolls, to improve the accuracy of the finished strips.

The economic effect of the introduction of the proposed device on a type 2800 reversing mill of the hot rolling of aluminum alloys is achieved in

performance gain and up to 200 thousand rubles. in year.

Claims (1)

1. USSR author's certificate No. 502671, cl. B 21 B 37/00, 197.