Patent ID: 6652041
Filing Date: 2003-11-25
Classification: B60T

Abstract:
A hydraulic pressure control device for a vehicle comprising:a proportional pressure control valve assembly which comprises: a housing formed with an input port, an output port and a discharge port; a spool valve slidably mounted in said housing and having a passage, said spool valve being movable between a first position in which said discharge port communicates with said output port through said passage and a second position in which said output port communicates with said input port through said passage, said spool valve also being positionable at a third position between said first and second positions in which said output port communicates with neither said discharge port nor said input port; a return spring biasing said spool valve toward said first position; a solenoid that produces an electromagnetic force to bias said spool valve toward one of said first and second positions, said spool valve having first and second pressure bearing surfaces that bear pressure introduced into said spool valve through said input port and said passage, said first and second pressure bearing surfaces being arranged such that the pressure acting on said first pressure bearing surface biases said spool valve toward said first position and the pressure acting on said second pressure bearing surface biases said spool valve toward said second position, said first pressure bearing surface having a greater area than said second pressure bearing surface, whereby the pressure acting on said first and second pressure bearing surfaces biases said spool valve toward said first position; and a brake pedal coupled to said spool valve through a spring such that a force applied to the brake pedal acts on said spool valve to bias said spool valve toward said second position.