Motor, a printer having such a motor and a disk drive system having such a motor
US5574322A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 1, 1993 |
| Grant date | Nov 12, 1996 |
| Priority date | — |
| Expiry date | Sep 1, 2013 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16C2370/12
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor has a rotor mounted on a stator to rotate about a rotation axis. The rotor is driven due to the interaction of a drive coil on the stator and a permanent magnet on the rotor. A magnetic thrust bearing, having permanent magnets on the stator and rotor, applies a radial thrust force. The radially outer surface of the permanent magnet on the rotor abuts a part of the rotor, so as to resist forces on the permanent magnet at high speed rotation or due to thermal deformation. The permanent magnets on the stator and the rotor may be axially offset by an offset of not more than 1/4 the axial length of the permanent magnets, or the axial length of the longer of the permanent magnets if they have different axial lengths. This generates an axial thrust at the thrust bearing, which counteracts the attractive force between the permanent magnet and the drive coil, and also the weight of the rotor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.