Pilot solenoid control valve and hydraulic control system using same

摘要

A pilot operated control valve (10) has a housing defining an inlet (18) and an outlet (20). A main valve poppet (24) selectively engages a valve seat (22) to control flow of fluid between the inlet and outlet. An aperture (34) in the main valve poppet opens into a control chamber (28) on a side of the main poppet remote from the valve seat. A pilot passage (30) is formed in the main valve poppet with an inlet section (26) between the inlet and the control chamber, and an outlet section (32) between the aperture and the control chamber. A pilot poppet (44) has a body that selectively seals communication between the control chamber and the aperture, and a pressure balancing stem (56) attached to the body extends into the aperture (34). The pressure balancing stem has a recess (58) which is acted upon by pressure in the outlet section and has an end (35) which is acted upon by pressure in the inlet section. The pilot operated control valve also incorporates a compression check valve (60) and/or a reverse flow check valve.