BRAKE BOOSTER FOR VEHICLE

摘要

PURPOSE: A brake booster of a vehicle is provided to reduce tolerance of clearance between a reaction disk and an end of a plunger, and to prevent sudden increase of output according to changes of clearance by forming an expanded recess in the end of a valve body. CONSTITUTION: A brake booster for a vehicle is composed of a casing having a front cell and a rear cell; a center plate dividing the casing into front and rear compartments; a valve body(60) regulating air inflow to front and rear compartment; an input shaft(40) operating the valve body; an output shaft(50) installed in the end of the valve body; a rubber reaction disk(51) contacted to the end of the valve body; a plunger(70) moving back and forth; and a recess(67) formed in the end(60a) of the valve body, and separated from the center of the reaction disk in braking. The diameter of the recess is formed to be less than the diameter of the reaction disk and more than the diameter of a cylinder part(66) to enlarge clearance between the reaction disk and the end of the plunger. The tolerance of the clearance is reduced with forming the expanded recess in the end of the valve body, and the sudden increase of the output is prevented according to changes of clearance.