Abstract: A brush holder device includes a brush including an integrally formed engagement portion; a brush arm having an engagement hole formed therein, the engagement hole assuming substantially the same shape as that of the engagement portion of the brush, and including brush contact portions located at laterally opposite edges of the engagement hole; and a holder. The holder has an engagement hole formed therein, the engagement hole assuming substantially the same shape as that of the engagement portion of the brush, and is fixedly attached to the brush arm such that the engagement hole is aligned with that of the brush arm. The engagement portion of the brush is press-fitted into the engagement holes of the holder and the brush arm, which are fixedly attached to each other, to thereby be fixed in place.

Abstract: An annular molded product of the present invention is molded by means of injecting a molten resin into a mold through an injection gate and cooling and solidifying the injected molten resin. The annular molded product is formed in the mold around a center pin having a diameter equivalent to the diameter of the circular center hole. The center pin axially extends further away from a position corresponding to the circular resin-molded product, whereby the injection gate is constituted by a tubular channel formed by a cylindrical annular clearance formed within the mold around an extended portion of the center pin. An annular gate trace is formed on the front or back surface of the annular molded product in such a manner as to project in an axial direction of the annular molded product.

Abstract: An annular molded product of the present invention is molded by means of injecting a molten resin into a mold through an injection gate and cooling and solidifying the injected molten resin. The annular molded product is formed in the mold around a center pin having a diameter equivalent to the diameter of the circular center hole. The center pin axially extends further away from a position corresponding to the circular resin-molded product, whereby the injection gate is constituted by a tubular channel formed by a cylindrical annular clearance formed within the mold around an extended portion of the center pin. An annular gate trace is formed on the front or back surface of the annular molded product in such a manner as to project in an axial direction of the annular molded product.

Abstract: A miniature motor includes: a plurality of magnets serving as stator poles and attached to an inner surface of a motor casing having a closed-bottomed cylindrical shape; a salient-pole rotor having a core mounted on a rotor shaft and windings placed on the core; and a commutator mounted on the rotor shaft. The core includes a center portion having a hole formed therein at the center for engagement with the rotor shaft, a plurality of leg portions extending integrally and radially from the center portion in equal number with the salient poles, and a plurality of wing portions, each extending integrally and symmetrically from an end of each of the leg portions. The core includes core laminations blanked from sheet steel and assembled together and is formed through deformation of the entire wing portions such that the radius of a circumcircle of the core coincides with a designed final radius of curvature of outer circumferential surfaces of the salient poles of the rotor.

Abstract: A brush holder device includes a brush including an integrally formed engagement portion; a brush arm having an engagement hole formed therein, the engagement hole assuming substantially the same shape as that of the engagement portion of the brush, and including brush contact portions located at laterally opposite edges of the engagement hole; and a holder. The holder has an engagement hole formed therein, the engagement hole assuming substantially the same shape as that of the engagement portion of the brush, and is fixedly attached to the brush arm such that the engagement hole is aligned with that of the brush arm. The engagement portion of the brush is press-fitted into the engagement holes of the holder and the brush arm, which are fixedly attached to each other, to thereby be fixed in place.

Abstract: A miniature motor includes: a plurality of magnets serving as stator poles and attached to an inner surface of a motor casing having a closed-bottomed cylindrical shape; a salient-pole rotor having a core mounted on a rotor shaft and windings placed on the core; and a commutator mounted on the rotor shaft. The core includes a center portion having a hole formed therein at the center for engagement with the rotor shaft, a plurality of leg portions extending integrally and radially from the center portion in equal number with the salient poles, and a plurality of wing portions, each extending integrally and symmetrically from an end of each of the leg portions. The core comprises core laminations blanked from sheet steel and assembled together and is formed through deformation of the entire wing portions such that the radius of a circumcircle of the core coincides with a designed final radius of curvature of outer circumferential surfaces of the salient poles of the rotor.

Abstract: A bearing 4 is accommodated within a cylindrical bearing support portion 2 projecting from an end surface of a motor casing 1 made of a metal. The bearing 4 has an outer diameter smaller than the inner diameter of the bearing support portion 2 such that a clearance is formed between the bearing 4 and the bearing support portion 2. At an approximate center of the bearing 4 with respect to the thrust direction, a projection 19 is continuously or non-continuously formed on the inner circumferential surface of the bearing support portion 2 along a circular line centered on the motor shaft. Further, a depression 20 corresponding to the projection 19 is continuously or non-continuously formed on the outer circumferential surface of the bearing 4 along the circular line. Thus, the bearing 4 is supported within the bearing support portion 2 in such a manner that thrust movement is prevented, but slight tilting about the projection 19 is permitted.

Abstract: A miniature motor includes: a plurality of magnets serving as stator poles and attached to an inner surface of a motor casing having a closed-bottomed cylindrical shape; a salient-pole rotor having a core mounted on a rotor shaft and windings placed on the core; and a commutator mounted on the rotor shaft. The core includes a center portion having a hole formed therein at the center for engagement with the rotor shaft, a plurality of leg portions extending integrally and radially from the center portion in equal number with the salient poles, and a plurality of wing portions, each extending integrally and symmetrically from an end of each of the leg portions. The core comprises core laminations blanked from sheet steel and assembled together and is formed through deformation of the entire wing portions such that the radius of a circumcircle of the core coincides with a designed final radius of curvature of outer circumferential surfaces of the salient poles of the rotor.

Abstract: A small-sized motor includes an insulation holder (16) which is integrally molded from a synthetic resin. The insulation holder (16) includes a cover portion (13) for-covering the casing cover (5) from the outside thereof, and a pair of brush holders (12) which project from the cover portion (13) into the interior of the motor, while passing through cut portions formed in the casing cover (5). Each of the brush holder (12) supports a brush arm (17) and an input terminal (11) connected thereto. The brush arm (17) supports a brush (18). Bearings (3) and (6) for the shaft are respectively supported at the center of the bottom portion of the casing (2) and at the center of the casing cover (5). Thus, it becomes possible to realize stable bearing alignment and to provide insulation outside the motor to thereby enable attachment of an electrical element to the motor without use of any additional insulation means.