Rare earth magnet rotors for watch movements and method of fabrication thereof
US6663827B2 · kind B2 · utility
0Cited by
10References
14Claims
0Family size
Inventors
Key dates
| Filing date | Mar 11, 2002 |
| Grant date | Dec 16, 2003 |
| Priority date | — |
| Expiry date | Mar 13, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K15/03
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Rotors for stepping motors used in analog timepieces are produced from a mixture of prealloyed rare earth magnetic particles and a thermoplastic binder. The mixture is either tape cast in a magnetic field following blanking of green rotors or injection molded in a magnetic field. Following extraction of the binder the green parts are sintered to net shape. Improved magnetic properties, smaller dimensions, better tolerances and 100% material utilization are claimed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.