Patent ID: 6053089
Filing Date: 2000-04-25
Classification: B60T

Abstract:
A hydraulic booster device chiefly comprising a housing including a cylinder bore, an inlet port connected to a pump and an outlet port for discharging a working fluid in said cylinder bore; a servo piston movably fitted into said cylinder bore and for defining a servo chamber communicating with said inlet port within said cylinder bore; a valve bore formed in said servo piston and for communicating said inlet port with said outlet port; and a spool movably inserted into said valve bore; and valve means comprising, as a main component, a spool movably inserted into said valve bore, and forming a clearance between a land portion on an outer periphery of said spool and an inner peripheral wall of said valve bore in response to an input made by a driver, thereby throttling a flow of a working fluid flowing towards said outlet port from said inlet port so that a working fluid pressure occurs within said servo chamber,wherein said valve means includes a first valve located nearer to said inlet port and a second valve located nearer to said outlet port, and a throttling area made by said second valve is larger than a throttle area made by said first valve.