Patent ID: 6179107
Filing Date: 2001-01-30
Classification: F16D,F16H,G05D,Y10T

Abstract:
A trim valve in a fluid control system for controlling the apply pressure to a torque transmitter, said fluid control system having means for supplying a range of control pressures, said trim valve comprising:a valve body having a fluid inlet means, a fluid outlet means connected with the torque transmitter and a fluid exhaust means;a sleeve valve slidably disposed in said valve body comprising an inlet port alignable with said fluid inlet means, an outlet port alignable with said fluid outlet means, and an exhaust port alignable with said fluid outlet means;a spool valve slidably disposed in said sleeve valve and having spaced valve lands for selectively connecting said inlet port with said outlet port while closing said exhaust port and for selectively connecting said outlet port and said exhaust port while closing said inlet port;a first spring means for biasing said spool valve in one direction;a control chamber receiving the control pressure to urge said spool valve in another direction;second spring means having a plurality of spring rates for biasing said sleeve valve in said one direction;a pressure bias chamber in fluid communication with said fluid outlet means for urging said second spring means in said other direction; andsaid sleeve valve being moved in said other direction during a first portion of said control pressure range against the influence of a first portion of said spring rates and being moved in said other direction during a second portion of said control pressure range against the influence of a second portion of said spring rates.