Brushless DC motor with permanent magnet rotor
US9401631B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 2013 |
| Grant date | Jul 26, 2016 |
| Priority date | — |
| Expiry date | Mar 28, 2034 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T29/49012
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
The brushless DC motor of the present invention comprises a permanent magnet rotor rotating coaxially with and inside of the stator containing the electric windings, separated by a radial, axially extending gap. The rotor can be formed of four or more permanent, e.g., ferrite ceramic magnets, spaced substantially equidistantly circumferentially around the rotor and extending radially along the axial length of the rotor. The preferred ferrite magnets are substantially corrosion resistant, and thus durable in the wet rotor environment, in which it may be used, sufficient to withstand the effects of even hot salt water. Preferably, four of the permanent magnets are bar magnets, i.e., rectangular in cross-section, extending radially and perpendicularly to the adjacent magnets. Most preferably, the bar magnets are separated by generally wedge-shaped, or quadrant-shaped, sections of magnetic material. The permanent magnets are polarized so that the north-south flux lines extend transversely to each adjacent magnet, most preferably forming a so-called Halbach Array. This brushless DC motor is especially useful for driving wet rotor pumps, wherein the particular combination of elements for…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.