Patent ID: 8049387
Filing Date: 2011-11-01
Classification: H02K

Abstract:
1. An electric motor comprising a stator and a rotor rotatably mounted confronting the stator, wherein the stator comprises: a housing having a cross section in a polygon shape that comprises a plurality of side portions and a plurality of curved corner portions, each of which connects two adjacent side portions, a ring magnet fixed onto an inner surface of the housing, the thickness of the ring magnet at portions corresponding to the corner portions of the housing being greater than the thickness of the ring magnet at portions corresponding to the side portions of the housing, an air gap being formed between a peripheral surface of the rotor and an inner surface of the ring magnet, the thickness of the air gap at portions corresponding to the corner portions of the housing being smaller than that of the air gap at portions corresponding to the side portions of the housing; wherein gaps are formed between the ring magnet and the corner portions of the housing.