Adjusting hydraulic cylinder on rolling mills - using servo-valve actuated by stepper motor

摘要

Hydraulic adjusting device for rolling mills, uses a servo valve contg. a piston and feeding a pressurised fluid to the adjusting cylinder. An electric stepper motor actuates the piston in the servo valve via a converter, changing the angular motion of the motor into the linear motion of the piston; and feedback is provided between the valve and the adjusting cylinder. One end of the piston is connected to a vibrator, where as the other end is connected via a spring to a ball nut moved linearly by a threaded spindle driven by the stepper motor; and a feedback pipe is connected between the servo valve and the adjusting cylinder; the vibrator reduces friction between the piston and the valve. The device can be used, e.g. on a two high mill for rolling blooms. Device has improved accuracy, sensitivity and reliability compared with conventional devices.