DC Brushless motor
US4417167A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 11, 1981 |
| Grant date | Nov 22, 1983 |
| Priority date | — |
| Expiry date | Dec 11, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K1/2791
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a DC brushless motor including a rotor assembly having permanent magnets and a stator assembly having coils arranged in the magnetic field generated by the permanent magnets of the rotor assembly, with the energization of the coils being controlled so as to impart a rotational torque to the rotor assembly; the permanent magnets of the rotor assembly are flat and are attached to a rotor yoke, which can be constructed as an octagonal prism, to provide a path for the magnetic flux emanating from the magnets and to support the flat magnets so that the latter form substantially a regular polygon in cross section. The magnets can be arranged with their poles in a north-south-north-south sequence against flat side walls of the rotor yoke to provide a flux density pattern that is substantially sinusoidal. Alternatively, the flat magnets can be arranged so that magnets of like polarization are disposed on either side of selected corners of a polygonal rotor yoke, thereby providing a flux density pattern that is substantially trapezoidal or rectangular.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.