US 5,287,793 AGranted

Power piston assembly for booster with diaphragm retainer

AssigneeJidosha Kiki Co., Ltd.

InventorsTohru Satoh, Atushi Satoh

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Abstract

A power piston assembly for booster, in particular, an improvement of an axial portion of a power piston and a retainer which is engaged therewith is disclosed. A front power piston is formed with a first and a second tubular section around its inner periphery, and the first tubular section is fitted around a flange of a valve body and is prevented from disengagement therefrom by an annular retainer. Around its outer peripheral edge, the retainer is formed with a peripheral tubular portion, which is disposed as a press fit around the second tubular section of the front power piston from the front side, thereby connecting the front power piston to the flange of the valve body. With this arrangement, the front end of the first tubular section of the front power piston may be located rearward of the front end of the valve body (or its flange). Accordingly, the axial size of the first tubular section and hence of the booster may be reduced as compared with a conventional arrangement.

Claims6

Dependent claims

A power piston assembly for a brake booster including a valve body having a flange formed around the periphery at its front end and which bulges radially outward, a power piston including a tubular section formed in its axial portion which is fitted over the flange of the valve body from the rear side and also including a positioning section which is formed at the rear end of the tubular section and which is disposed in abutment against the rear end face of the flange, and an annular retainer for preventing the tubular section of the power piston from being disengaged from the flange;

the power piston assembly being characterized in that the front end of the tubular section is folded upon itself to extend rearwardly to define a second tubular section at a location outward of the first mentioned tubular section, the retainer being disposed in abutment against the front end face of the valve body and including an outer peripheral edge which is extended rearwardly to define a peripheral tubular portion, which is fitted around the second tubular section of the power piston from the front side, the peripheral tubular portion being formed with a plurality of engaging pawls projecting inwardly therefrom and engaging the outer peripheral surface of the second tubular section.

Dependencies are inferred from the claim text.