Two-axis motor with high density magnetic platen
US6005309A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1998 |
| Grant date | Dec 21, 1999 |
| Priority date | — |
| Expiry date | Apr 23, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T74/20201
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An X-Y positioning machine has a forcer, with armature coils, that moves around on a platen, supported by an air bearing. Magnets embedded in the motor platen generate a fixed magnetic field with which the armature coils interact. Perpendicular elongated coils interact with the fields of magnets in columns and rows. When a traditional rectangular pattern of the magnets is provided, a packing density and average peak magnetic flux intercepted by the coils are limited to 50%. The present invention provides magnet configurations that provide greater than 50% maximum peak flux density and up to 100% packing density. Several magnet arrangements are provided: a first in which round magnets are used instead of square, and a second in which diamond shaped magnets are used. The latter can be used at 100% packing density arrangement. In addition to high peak flux density for a narrow coil, these embodiments exhibit low cogging forces. A method of making the magnet is also provided. To create the equivalent of a closely-packed array of circular magnets, a single sheet of magnetizable material is pressed against an high permeability element such as one of iron, and a pair of adjacent coils pre…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.