Patent ID: 9533664
Date: 2017-01-03
CPC Classifications: B23P,B60T,Y10T

Claim:
1. A method of manufacturing a plate plunger with which a reaction disc comes into contact and which determines a servo ratio of a vacuum booster, the plate plunger manufacturing method comprising: a) processing a plate plunger base material in a primary process in such a way that an outer peripheral diameter of a reaction disc contact surface of the plate plunger base material becomes equal to or greater than an outer peripheral diameter corresponding to the smallest servo ratio among a variety of different servo ratios; and b) forming the reaction disc contact surface of the plate plunger in a secondary process that is different from the primary process so that the outer peripheral diameter of the reaction disc contact surface corresponds to a desired servo ratio, wherein the secondary process includes removing material of the reaction disc contact surface to form a servo ratio determination surface that determines the servo ratio on a corner portion between an outer peripheral diameter of the plate plunger and a surface of the plate plunger that opposes the reaction disc.