Hydraulic actuator control device - has motor responsive to electrical signal to move pilot valve spool causing main valve spool to move to corresp. position

摘要

Device controlling a hydraulic actuator in response to an electrical input signal has a main valve having a fluid pressure operated main spool which controls fluid supply to the actuator. A pilot valve has a pilot spool regulating fluid pressure operating the main spool. A motor produces a force depending on the input signal to move the pilot spool against a fluid pressure. The fluid pressure operating the main spool also acts on the pilot spool in opposition to the force from the motor so that the position of the main spool depends on the input signal to the motor.