Transmission piston and method of making the same
US4485656A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1982 |
| Grant date | Dec 4, 1984 |
| Priority date | — |
| Expiry date | Aug 27, 2002 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49265
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
The invention pertains to a piston for use in vehicle automatic transmissions and the method of making the same. An automatic transmission piston is of an annular configuration having a radial pressure face and an axially extending flange which includes an outer periphery in which a seal receiving groove is defined. The invention produces the piston from a sheet metal stamping blank and the blank flange is of a greater axial dimension than that of the flange after forming. The seal receiving groove is formed in the piston flange by a rolling operation, and during the rolling the axial dimension of the flange is reduced by compression of the flange material wherein the metal radially displaced is provided by the flange compression and the radial dimension of the flange thickness is substantially maintained during and after rolling as the simultaneous compression of the flange during the rolling of the seal receiving groove provides the extra metal required without producing a deficiency in the piston dimensions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.