Pressure control valve with pressure cycling control

摘要

A spool valve includes a housing having a spring-enclosing portion and a spool-enclosing portion aligned along a longitudinal axis. A spool is mounted for reciprocal axial movement in the housing and a piston is fixed to one end of the spool. The spool-enclosing portion supports a stationary bushing having a bore receiving an opposite control end of the spool, the bushing formed with a first plurality of radially-oriented passages opening into an annular groove formed in the bore, the groove having sloped side edges. The spool supports plural ring-seals arranged to engage the sloped side edges of the annular groove and thereby seal off the radially-oriented passages when the spool is in a neutral position. Movement of the spool is adjustably limited in one direction and dampened in both axial directions.

主权项

1. A spool valve comprising:
a housing including a spring-enclosing portion and a spool-enclosing portion aligned along a longitudinal axis; a spool mounted for reciprocal axial movement in said spool-enclosing portion; a piston fixed to one end of the spool; said spool-enclosing portion supporting a stationary bushing having a bore receiving an opposite control end of the spool, the bushing formed with a first plurality of radially-oriented passages opening into an annular groove formed in said bore said groove having sloped side edges said first plurality of radially-oriented passages aligned with a first radial port provided in said spool-enclosing portion; a sealed chamber on one side of said piston defined by a diaphragm engaged with one side of said piston and an end face of said spool-enclosing portion, said sealed chamber in communication with a second radial port provided in said spool-enclosing portion; a spring supported in said spring-enclosing portion engaged between a distal end of said spring-enclosing portion and the other side of said piston; and said opposite end of the spool supporting plural ring-seals arranged to engage the sloped side edges of the annular groove and thereby seal off said radially-oriented passages when said spool is in a neutral position, and to resiliently engage said sloped side edges upon axial movement of the spool in either of two opposite, axial directions to thereby resist axial movement away from said neutral position.