Linear actuator
US5245232A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 2, 1992 |
| Grant date | Sep 14, 1993 |
| Priority date | — |
| Expiry date | Mar 2, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/34
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A linear actuator for e.g. a disk drive has a fixed member and a movable member. One of those members carries at least one track of permanent magnets extending in the direction in which the movable member is to move, with adjacent permanent magnets having alternate magnetic polarity. The other member has first and second drive parts, each having at least one pair of opposing sets of teeth. The moveable member or each track passes between those teeth. Each pair of teeth is associated with a corresponding drive coil giving the teeth a magnetic polarity so that there is a magnetic alignment between a polarity of the teeth and the permanent magnets. The drive parts are arranged so that, for any given relative position of the first and second members, the magnetic alignment of the teeth of one drive part is out of phase with the magnetic alignment of the teeth of the other part. In order to ensure that the magnetic alignments are out of phase, there may be a physical displacement between the teeth of the two drive parts. This displacement may be (m.+-.1/2).multidot.T.sub.p, where m is an integer and T.sub.p is the teeth pitch. This gives a phase displacement of 180.degree.. Alternativel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.