Patent ID: 6796330
Filing Date: 2004-09-28
Classification: F16H,G05D,Y10T

Abstract:
A pressure control apparatus for a torque-transmitting mechanism comprising:a pressure source; a control source; a valve body including a valve bore communicating with both said pressure source and said control source; a valve spool slidably disposed in said valve bore and including a differential area formed by said valve spool and said valve bore; an outlet port connected between said valve bore and said torque-transmitting mechanism and directing an engagement pressure therebetween; said valve spool being operative in response to pressure from said control source to control fluid pressure communicated between said pressure source and said torque-transmitting mechanism; a boost valve disposed within said valve spool and being responsive to said control source to control fluid pressure distribution to said differential area to thereby control the engagement pressure levels at the torque-transmitting mechanism; said boost valve comprising a body portion, a pair of valve seats, a ball three port means, and an actuator means; said being urged onto one of said valve seats by fluid pressure at said outlet port to open communication between a first and second of said port means and being urged toward said other of said valve seats by said actuator means in response to said control pressure to open communication between said second port means and said third port means, said second port means being in fluid communication with said differential area.