Patent ID: 6668552
Filing Date: 2003-12-30
Classification: B60T

Abstract:
A hydraulic brake booster for use in a brake system having a housing with a first stepped bore separated from a control bore, said first stepped bore retaining a piston arrangement and said control bore retaining a control valve, said first stepped bore being connected to a first set of wheel brakes, said control bore being connected to a source of pressurized supply fluid, to said first stepped bore and to a second set of wheel brakes of a vehicle, an input member connected to said piston arrangement, said control valve being responding to an input signal derived from an input force applied by an operator through said input member to said piston arrangement to effect a brake application by communicating regulated pressurized supply fluid from said control bore to said first stepped bore and!to said second set of wheel brakes, said regulated pressurized supply fluid received by said first stepped bore acting on and moving said piston arrangement in said first stepped bore to pressurize operational fluid therein that is supplied to effect the application of said first set of wheel brakes, said hydraulic brake booster being characterized by said piston arrangement having a cylindrical member with a first peripheral surface concentrically located in said first stepped bore to define an output chamber, a relief chamber and an power chamber in said housing, said cylindrical member having a second stepped bore therein for receiving a reaction piston, said reaction piston having a second peripheral surface concentrically located in said second stepped bore and an axial bore therein, a plunger located in said axial bore to define an actuation chamber, said plunger being connected to said input member, and poppet valve means located in said axial bore for controlling communication of fluid between said actuation chamber, said relief chamber and said control bore, said input force on being applied by an operator to said input member initially moving said plunger and poppet valve means to interrupt communication from said actuation chamber to said relief chamber and thereafter moving said plunger to pressurize fluid in said actuation chamber and create said input signal for activating said control valve in said control bore whereby said regulated pressurized supply fluid is supplied said power chamber for moving said first cylindrical body toward said output chamber to pressurizing fluid in the output chamber to a predetermined level to create said operational fluid that is communicated to effect the actuation of said first wheel brakes during a brake application.