Electric motor

摘要

An electric motor includes a cylindrical yoke main body and a plurality of permanent magnets having an arcuate cross-section. The permanent magnets are secured to a inner circumferential surface of the yoke main body such that the permanent magnets are continuous with one another along the entire circumference of the yoke main body, thereby forming a ring. An even number of magnetic poles are formed in the permanent magnets at predetermined angular intervals along the circumferential direction of the yoke main body. A pair of the magnetic poles that are adjacent to each other in the circumferential direction of the yoke main body have different magnetic polarities from each other. At least one of the permanent magnets is provided with a section where the magnetic polarity changes in the circumferential direction of the yoke main body. This suppresses vibration excited in a stator that causes vibration and noise.