Electric motor with a multipolar permanent magnet rotor
US4714854A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 30, 1986 |
| Grant date | Dec 22, 1987 |
| Priority date | — |
| Expiry date | Jun 30, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K37/125
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric motor which delivers a high torque per Ampere-turn and a high power rate and acceleration of the rotor. Maximum torque per Ampere-turn is accomplished by setting a minimum air-gap width in the range defined by the relationship 0.389 P+1.4.ltoreq.P/E.ltoreq.0.706 P+1.85, with P being the space in millimeters between the centers of the magnetic poles of like polarities of a multipolar permanent magnet arrangement disposed on the rotor and between the centers of regions of minimum width of the air-gap, and E being the width in millimeters of the air-gap. The air-gap refers to the space between opposite parts of permeable magnetic material and thus defines the entire space in which a permanent magnet is placed. In one construction of the invention, the motor comprises a flat annular disk mounted for rotation on a motor shaft, and the stator comprises a plurality of tooth-shaped polar portions facing other polar portions on either side of the annular disk in a direction parallel to the shaft of the disk. The annular disk contains portions of alternating polarity which sequentially pass the tooth-shaped polar portions during rotation of the disk. It is further advantageous to…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.