Patent ID: 6386648
Filing Date: 2002-05-14
Classification: B60T

Abstract:
A brake system for a vehicle having a brake booster for providing a primary piston in a master cylinder with an input force to pressurize fluid which is supplied to wheel brakes of a vehicle to effect a brake application in response to an operator input force, said master cylinder having a first housing with a bore therein, said bore having a first compensation port connected to a fluid supply and a first outlet port connected to said wheel brakes, said primary piston being located in said bore to define an first pressure chamber therein, said primary piston having a first position of rest whereby said first pressure chamber is connected to said fluid supply, said brake booster having a second housing with an interior separated by a movable wall into a front chamber and a rear chamber, said front chamber being connected to a first fluid at a first pressure and said rear chamber being selectively connected to said first fluid and to a second fluid at a second pressure as a function of a force applied to a control valve, a first return spring for positioning said movable wall in a second position of rest whereby said first fluid is communicated to said front and rear chambers and an output push rod connected to said movable wall, said control valve being responsive to an operator input for terminating communication of said first fluid to said rear chamber and initiating communication of said second fluid to said rear chamber for creating an pressure differential across said movable wall, said pressure differential acting on said movable wall to develop an operational force which after overcoming said first return spring moves said movable wall from said second position of rest toward said master cylinder, said operational force being communicated through said output push rod to move said primary piston from said first position of rest past said first compensation port to thereafter pressurize fluid in said first pressure chamber, said pressurized fluid being supplied from said first chamber to said wheel brakes through said first outlet port to effect a brake application, said brake system being characterized by connecting means for joining said primary piston with said output push rod such that said primary piston is moved toward said first position of rest by said return spring returning said movable wall to said second position of rest in an absence of an operator input being applied to said control valve and means for adjusting the position of said primary piston within said bore to assure that said compensation port is fully connected with bore in said first position of rest.