Patent ID: 6957665
Filing Date: 2005-10-25
Classification: F15B,F16K,Y10T

Abstract:
1. A spool valve comprising: a sleeve having supply channels, return channels and control channels and a spool having a plurality of spool lands connected to one another by a spool rod, said channels being opened and closed by the spool which reciprocates in the sleeve and a flow force compensating stepped shape formed on the spool rod, said stepped shape being adjacent to a spool land at a supply channel, wherein the stepped shape comprises a first surface which starts from the surface of spool rod and is perpendicular to the longitudinal axis of spool rod, a second surface which is parallel to the longitudinal axis of spool rod and is perpendicular to the first surface, and an end surface which is perpendicular to the second surface and is formed between the second surface and the top surface of the spool land.