Mabuchi Motor Co., Ltd.

Yusuke Miyajima

Masahiko Kato

A rotor core includes: an annular part around a through hole; a plurality of fan-shaped magnetic pole pieces radially formed around the annular part; and a plurality of magnet holders radially formed between adjacent magnetic pole pieces, and a plurality of first magnetic flux blocking parts formed in respective areas between adjacent magnet holders. The magnet holder includes a second magnetic flux blocking part at an end of the magnetic holder toward the rotating shaft. The rotor core includes two magnetic paths formed between the first magnetic flux blocking part and the two second magnetic flux blocking parts adjacent to the first magnetic flux blocking part. The two magnetic paths branch in different directions toward the annular part from the end of the magnetic pole piece toward the rotating shaft.

Brushless motor with permanent magnet rotor with magnetic poles with flux blocking parts/through holes towards the shaft forming angles

A brushless motor includes: a columnar rotor including magnets; a stator including at its center a space for placing the rotor; a housing member that houses the rotor and the stator; and a detector that detects a signal dependent on a rotational position of the rotor based on variation in a magnetic field associated with a rotation of the rotor. The housing member includes a front bell that supports a portion of the rotating shaft of the rotor and a housing body that supports another portion of the rotating shaft of the rotor. The front bell includes a mount fitted with the detector. The mount projects from the base toward an end face of the rotor.

Brushless motor

A DC motor comprises: a tubular metal case; a magnet that is provided along the inner surface of the metal case and has four or more of magnet poles in the circumferential direction; an armature that is arranged to face the magnet and composed of a core and a coil; and a shaft. The magnet is formed of a material with a maximum energy product BHmax of 3 to 6 MGOe. When the thickness of the magnet in the radial direction of the armature is indicated by T [mm] and the outer diameter of the core is indicated by d [mm], the ratio T/d of the thickness T of the magnet to the outer diameter d of the core is 0.16 or more.

DC motor

A type-A winding represented by a triangle of solid lines is connected to commutator segments such that its one end is connected to an arbitrary commutator segment and its other end is connected to a commutator segment adjacent to the arbitrary commutator segment. A type-B winding represented by a diamond of broken lines is connected to commutator segments such that its one end is connected to a commutator segment located radially opposite to a usual adjacent commutator segment. The type-A windings and the type-B windings are used in combination. One short circuit wire is used for every short circuit connection of radially opposed commutator segments. A total number of the short circuit wires is half (5) the number (10) of commutator segments. Thus, the number of electric wires hooked at every commutator segment can be reduced to two or less. Also, continuous winding by use of one or two wires is possible.

Miniature motor, and its manufacturing method

A cooling fan includes a fan ring to be attached to an end surface of a rotor core near the outer circumference thereof, and a plurality of fins connected to the fan ring. The fan ring has positioning leg portions provided on an end surface thereof facing a thrust direction. The fan ring is positioned in relation to the rotor core through insertion of the positioning leg portions into core slots of the rotor core. The fan ring has wire accommodation recesses which are formed on the end surface of the fan ring facing the thrust direction and communicate with the core slots.

Growing community of inventors

Matsudo, Japan

Yusuke Miyajima