Nissin Kogyo Co., Ltd.

Hidemitsu Sunohara

Toshiyuki Suwa

Akihiro Rokugawa

A hydraulic master cylinder for vehicle has: a cylinder main body; a sleeve; a plurality of seal rings; a plug, a lid member comprising the sleeve and the plug; and a piston inserted into the cylinder bore so as to form a hydraulic pressure chamber between the piston and the lid member; wherein the sleeve is inserted into the cylinder main body with an open end thereof being made to face an interior of the cylinder main body so as to dispose the seal rings between a circumferential wall of the cylinder bore and the sleeve and in such a manner that the seal rings hold the outlet port therebetween, and the plug is fixedly threaded in the opening at the one end so as to prevent the dislocation of the sleeve.

Hydraulic master cylinder for vehicle

A vacuum booster has a booster shell formed of a front shell half and a rear shell half interconnected at their open ends opposed to each other, and a diaphragm which divides the shell interior into a vacuum chamber on the front shell half side and a working chamber on the rear shell half side. An outer peripheral bead portion of the diaphragm is clamped between the open ends of both the shell halves with an outer surface of the outer peripheral bead portion being contacted under pressure with an inner surface of the open end of the front shell half. The outer peripheral bead portion is provided at an outer periphery thereof with a first tapered surface tapered toward the front shell half and a second tapered surface tapered toward the rear shell half such that the first and second tapered surfaces are formed into an angled shape in their cross section. Thus, the frictional resistance upon the insertion of the diaphragm during assembling of the vacuum booster can be made relatively small, thereby improving an assembling and insuring a sufficient sealing by the outer peripheral bead portion.

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Nagano, Japan

Hidemitsu Sunohara