Patent ID: 6386087
Filing Date: 2002-05-14
Classification: B60T

Abstract:
A control booster comprising:a power piston dividing an inside of a housing into a constant pressure chamber and a variable pressure chamber; a valve mechanism which controls supply of a working fluid to the variable pressure chamber in accordance with movement of a plunger connected to an input rod associated with a brake pedal, the valve mechanism being provided in a valve body supported by the power piston; an electromagnetic bias means having a movable element which operates the valve mechanism independently of operation of the input rod, the control booster being adapted to generate a thrust in the power piston due to a differential pressure generated between the variable pressure chamber and the constant pressure chamber based on operation of the valve mechanism; a switch for detecting relative movement of the input rod relative to the valve body; a switch operating rod for operating the switch; and a switch spring for biasing the switch operating rod in a direction for pushing-in a contact operating element of the switch, wherein when the input rod is operated in a direction for increasing an output of the booster in a state where a reaction force of the switch acting on the switch operating rod and a spring force of the switch spring are balanced, the switch operating rod moves in a direction for separation relative to the switch.