Method of making polytetrafluoroethylene sealing elements with hydrodynamic action
US3939551A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 4, 1975 |
| Grant date | Feb 24, 1976 |
| Priority date | — |
| Expiry date | Feb 4, 1995 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49918
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
A method for manufacturing an oil seal element from polytetrafluoroethylene and the like. A tubular billet of polytetrafluoroethylene or the like is provided with an outer cylindrical surface of the desired diameter and an inner cylindrical surface approximating but slightly smaller than the desired diameter, and an end wall is faced off perpendicular to the cylindrical surfaces. A series of washers of a desired thickness is then sliced from the billet. The flat washer is then first assembled with a metal case and then a desired hydrodynamic shape, such as a spiral groove, is coined in. Preferably, the inner pierce is completed at this time. Each washer may then be formed under pressure to permanently deform the radially inner portion thereof to a frustoconical shape. The assembled seal may be held on a shaft-size mandrel during application of a coating to the metal case.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.