PERMANENT MAGNET FIELD TYPE DC MOTOR, STATOR THEREFOR, AND RARE-EARTH ANISOTROPIC BOND MAGNET

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PROBLEM TO BE SOLVED : To provide a permanent magnet field type DC motor in which high output, reduction of current supply, or reduction of a spark generated between a brush and a commutator can be achieved, while the use amount of rare-earth anisotropic magnet powder which is expensive is reduced.SOLUTION : The present invention is a permanent magnet field type DC motor comprising a rotor having an armature, a stator (S1) surrounding the rotor and having a field source which is a permanent magnet, a commutator continuous with a coil of the armature, and a brush which comes into sliding contact with the commutator so as to supply DC power to the coil. The stator according to the present invention comprises a tubular yoke (12) having a substantially cylindrical outer circumferential surface, and a tubular rare-earth anisotropic bond magnet (11) fixed to the inner circumferential surface side of the yoke. The rare-earth anisotropic bond magnet comprises an inner circumferential surface formed of a cylindrical surface, and an outer circumferential surface having a smoothly curved surface swelled further toward the diameter expansion direction than a magnetic pole boundary where the respective centers of magnetic poles are adjacent to each other.SELECTED DRAWING : Figure 5COPYRIGHT : (C)2019, JPO&INPIT