Patent ID: 6321633
Filing Date: 2001-11-27
Classification: B60T

Abstract:
A booster comprising:a housing;a power piston dividing the interior of the housing into a constant pressure chamber and a variable pressure chamber;a valve body supported by said power piston;a plunger provided in said valve body for axial movement;an input rod interconnecting a brake pedal and said plunger so that the operation of the brake pedal is transmitted to the plunger to cause its axial movement;a valve mechanism provided in said valve body for controlling supply of operating fluid to said variable pressure chamber in response to the axial movement of said plunger so that a thrust output force is generated by pressure difference created between said variable pressure chamber and said constant pressure chamber based on the operation of said valve mechanism; andan electromagnetic biasing device including a movable member slidably provided in said valve body and having one end for operating said valve mechanism independently from the operation of said input rod,wherein, said electromagnetic biasing device is so arranged that the pressure in said variable pressure chamber acts on said one end of said movable member and the pressure in said constant pressure chamber acts on the other end of said movable member.