Pilot controlled hydraulic valve - uses pilot valve with proportional solenoid for controlling flow to coupled actuator

摘要

A pilot controlled hydraulic valve system is used to maintain a constant speed of operation of a coupled actuator. The main control valve (3) has a spool (5) that regulates the flow from a pump (1) to a load actuator (10) over a valve port (7). In the neutral position the spool is biased into the 'off' position by a coil spring (8). Movement of the piston and the consequent adjustment of the flow rate is controlled by a control flow (19) applied to the topside of the piston. The control flow is provided by a pilot valve (4) that regulates the flow from the supply (2). A spool (13,14) is moved by a proportional solenoid (17) that reacts to a position signal generated by an inductive transducer (23) built into the main valve.