Method and apparatus for hardening gears and similar workpieces
US4855556A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 21, 1988 |
| Grant date | Aug 8, 1989 |
| Priority date | — |
| Expiry date | Jun 21, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC21D9/32
- WIPO fieldMaterials, metallurgy
- WIPO sectorChemistry
Abstract
A method and apparatus for progressively hardening an elongated workpiece having an outer generally cylindrical surface concentric with the central axis including the concept of providing closely spaced first and second induction heating coils each having workpiece receiving openings generally concentric with the axis of the workpiece; energizing the first coil with a low frequency such as a frequency less than about 50 KHz; energizing the second coil with a high radio frequency, such as the frequency exceeding 100 KHz; causing relatively axial and progressive motion between the workpiece and the first and second closely spaced coils in a direction entering the first coil and exiting the second coil whereby the cylindrical surface is progressively first preheated by the first coil and then immediately final heated by the second coil; and, then immediately quenching the cylindrical surface as it passes from the second coil whereby the cylindrical surface is progressively preheated, heated and quench hardened as the workpiece is moved through the induction heating coil.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.