Mabuchi Motor Co., Ltd.

Keisuke Ebihara

Kazuo Okada

Kazumasa Saiga

A miniature motor including a motor case formed into a bottomed hollow cylindrical shape having a cross-sectional shape having two long sides consisting of two parallel lines (planar portions) and two short sides. An end bracket is fitted to an open end of the motor case. Permanent magnets are fixedly fitted to the cylindrical inside surface of the motor case. The inside surfaces of the permanent magnets, when assembled, form part of a cylindrical surface. An armature is rotatably supported in the motor case via bearings provided on the motor case and the end bracket. Recesses are provided on the inside of the parallel planar portions of the motor case and positioned in such a manner that a gap g.sub.1 between the inside surfaces of the recesses and the armature is related to a gap g.sub.2 between the inside surfaces of the permanent magnets and the armature by a relationship that g.sub.1 g.sub.2. A method is further proposed of making the motor in which the recesses are formed by ironing.

Miniature motor and method of making same

A miniature motor comprising a case formed into a bottomed hollow tubular shape and having permanent magnets fixedly fitted to the inner circumferential surface thereof, a rotor consisting of an armature and a commutator, and a case cover engaged with an open end of the case and having brushes making sliding contact with the commutator, and input terminals electrically connected to the brushes, in which fixing ribs are provided on the inner circumferential surface of the case, extending along the axial direction of the case; the edges of the permanent magnets formed into an arc-segment cross-sectional shape being caused to make contact with the side edges of the fixing ribs to fixedly fit the permanent magnets to the inner circumferential surface of the case; projections formed integrally with the permanent magnets along the edges of the permanent magnets are provided facing the surface of the fixing ribs.

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Matsudo, Japan

Keisuke Ebihara