PERMANENT-MAGNET-FIELD DC MOTOR AS WELL AS STATOR THEREFOR AND RARE EARTH ANISOTROPIC BOND MAGNET TH

文件类型：PDF文档
文件大小：2089K
The present invention provides a permanent-magnet-field DC motor that increases to a higher output, and reduces the supply current or reduces the spark that occurs between a brush and a commutator, while reducing the usage amount of an expensive rare earth anisotropic magnetic powder. The present invention is a permanent-magnet-field DC motor comprising : a rotor having an armature; a stator (S1) surrounding the rotor, the stator having a permanent magnet as a field magnet source; a commutator linking to a coil of the armature; and a brush in sliding contact with the commutator, the brush supplying DC power to the coil. The stator according to the present invention has a cylindrical yoke (12) having a substantially cylindrical outer circumferential surface, and a cylindrical rare earth anisotropic bond magnet (11) secured to the inner-circumferential-surface side of the yoke. This rare earth anisotropic bond magnet comprises an inner circumferential surface comprising a cylindrical surface, and an outer circumferential surface having a smooth curved surface that bulges outward further in the diameter-increasing direction relative to the boundary between magnetic poles having adjacent centers.