Solenoid-actuated directional control valve

Claim 1

A three chamber solenoid-actuated directional control valve comprising: a valve housing having a bore extending longitudinally therethrough; a spool having at least one land thereon reciprocally mounted within said bore and defining with said housing, between first and second ends of said spool, three chambers, a first chamber being adapted to be connected to a pump for supplying hydraulic fluid, a second chamber being adapted to be connected to a first load and a third chamber being adapted to be connected to a second load and defining with said housing at least one recess adapted for connection to a tank and located between one of said ends and said chambers; throttle means on said at least one land between at least one chamber and said recess; solenoid means in said spool including a solenoid housing having an inner bore surface defining a bore extending therethrough along said bore direction from said one end of said spool, an armature reciprocally mounted for longitudinal movement along said bore direction in response to actuation of said solenoid means, and an actuating rod fixedly mounted to said armature for actuating said spool when said solenoid means is actuated, a space being defined between the end of said armature remote from said spool and said valve housing and at least one armature groove being formed between the outer surface of said armature and said inner bore surface of said solenoid housing and connected to said recess; and motion damping means including at least a single cross wall between said space and said groove adjacent said remote armature end and having a throttling groove between said cross wall and said inner bore surface for dampening movement of said armature to reduce pressure peaks during switching.