Voice coil motor dummy magnet
US6606223B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 17, 2001 |
| Grant date | Aug 12, 2003 |
| Priority date | — |
| Expiry date | Sep 4, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/5521
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A voice coil motor assembly in a disc drive includes first and second pole pieces held in spaced relationship to one another such that a gap is defined therebetween. A permanent magnet is located on the first pole piece within the gap and a dummy magnet is located on the second pole piece across the gap from the permanent magnet. The first and second pole pieces, together with the magnet and the dummy magnet, form a magnetic circuit conducting lines of magnetic flux within the voice coil motor and across the gap. The dummy magnet acts to encourage magnetic flux to flow across the gap in a manner such that the roll and pitch torque constants of the voice coil motor are reduced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.