Sheet metal piston for transmissions and method of making a piston assembly

摘要

A multi-speed transmission with piston assemblies made from sheet metal stampings for selective engagement with multi-disc friction devices. Each piston assembly comprises a thin wall shell stamped from sheet stock. The shells have outer and inner support shoulders adjacent to outer and inner rims onto which are pressed annular retainers that form grooves for elastomeric lip seals. In one embodiment the contact member for the piston assembly comprises a sheet metal member curved until the ends almost meet. The contact member is retained in a shell by its expansion force acting against an annular retainer wall. In a second embodiment the contact member is formed by extending the outer rim axially.