| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric motor in which vibration is reduced, by reducing the cogging torque, and the motor efficiency can be improved. SOLUTION: The electric motor 2 comprises a yoke 5 having a tubular portion 53, at least a pair of permanent magnets 7, having a substantially crescent cross-section arranged on the inner circumferential surface of the tubular portion 53; and an armature 6 having an armature core 8 provided rotatably on the inside of the yoke 5, wherein the radius of curvature R1 at the inside arcuate portion 56 of the permanent magnet 7 is set larger than the radius of curvature R2 at the outside arcuate portion 57 of the permanent magnet 7. The air gap S2, between the inside arcuate portion 56 and the outer circumferential surface of the armature core 8, is set so as to become constant in the circumferential direction. COPYRIGHT: (C)2009,JPO&INPIT
|
