Patent ID: 6561596
Filing Date: 2003-05-13
Classification: B60T

Abstract:
A hydraulic brake booster for use in a brake system having a housing with a first bore separated from a second bore, said first bore retaining a first piston and said second bore retaining a control valve, an input member connected to said first piston and linked to said control valve by a lever arrangement, said second bore being connected to a source of pressurized supply fluid and said first bore being connected to wheel brakes of a vehicle, said control valve being responsive to a braking force applied by said input member for communicating regulated pressurized supply fluid that acts on and moves said first piston in said first bore to pressurize operational fluid that is supplied to said wheel brakes and effect a brake application, said hydraulic brake booster being characterized by a first passage that connects said second bore to said first bore for communicating said regulated pressurized supply fluid to said first bore, said first piston cooperating with said housing to define an actuation chamber within said first bore for receiving said regulated pressurized supply fluid, said regulated pressurized supply fluid in said actuation chamber acting on and moving said first piston to develop said operational fluid that is communicated to a first set of wheel brakes to effect a brake application and said regulated pressurized supply fluid being communicated from said second bore to a second set of wheel brakes to effect a brake application therein, said first piston having an annular projection that extends through an opening in said housing with a third bore therein, a reaction piston connected to said input member and located in said third bore to define a reaction chamber, said actuation chamber being connected to said reaction chamber such that said regulated pressurized supply fluid acts on said reaction piston to provide an operator with an indication of the development of said operational fluid in said first bore, and wherein said control valve includes a cylindrical member located in said second bore to define a supply chamber within said second bore that is connected to said pressurized supply fluid, said cylindrical member having an axial seat thereon and a first stem member that is located in said supply chamber has a face thereon that is urged toward said axial seat by a first spring to close said supply chamber and retain said pressurized supply fluid within said supply chamber.