Koyo Seiko Company, Ltd.

Jtekt Corporation

Minoru Kitabayashi

Tomofumi Takahashi

Hirohide Inayama

Tetsuo Horie

Atsushi Ishihara

Sadaaki Mori

Hideki Jonokuchi

Ken Matsubara

A rotary shaft of a rotor including a magnet with a plurality of magnetic poles arranged at equal intervals on an outer circumference is supported at both ends by bearings. By externally fitting the inner ring of one bearing to the rotary shaft and holding it to be immovable in an axial direction and loosely fitting the outer ring of the bearing into the support hole and positioning it with belleville springs which are in contact resiliently with both sides, the rotary shaft and the rotor are supported so that they are movable in an axial direction within a movement amount of not greater than 2 mm according to a movement of the bearing caused against spring forces of the belleville springs.

Brushless motor

A bridge () in conformity with a tooth opening angle of the stator () is provided between a permanent magnet () and a permanent magnet () in a rotor (), so that a magnetic flux for a reluctance torque is made to pass an inner side of the permanent magnet (). An opening angle of each of ribs () on both sides of the permanent magnet () is set to be equal to or smaller than the teeth interval opening angle and equal to or larger than a half thereof. Thereby, reluctance of the rib () against a magnetic flux in a circumferential direction is increased and leakage of the magnetic flux of the permanent magnet () is prevented.

Brushless DC motor

A brushless DC motor including a stator having plural slots; and a rotor which has plural permanent magnets and is divided into three rotor blocks in a rotation axis direction, the three rotor blocks being layered so that the arrangement angles of the rotor blocks differ from each other by an amount of a mechanical angle in a rotary direction that is equivalent to one third of a pulsation period of cogging torque generated by the rotor and stator. A brushless DC motor including a rotor having plural magnetic poles provided at an equal pitch in a circumferential direction by mounting permanent magnets in magnet mounting holes; and a stator having plural slots arranged at an equal pitch in a circumferential direction. The magnetic poles of the rotor include magnetic poles whose magnet deviation angle formed by the central line of an effective polar opening angle and the central line of the magnet mounting hole is the first angle; and magnetic poles whose magnet deviation angle is the second angle different from the first angle.

Brushless DC motor and method of manufacturing brushless DC motor

In a brushless DC motor constructed by a rotor to which a permanent magnet is attached; and a stator having a plurality of slots, when an effective opening angle of magnetic pole of the rotor that was set to a predetermined opening angle whose base is the rotation axis of the rotor is &thgr;2 and a salient area opening angle of magnetic pole formed within the effective opening angle &thgr;2 of magnetic pole is &thgr;3, the opening angles &thgr;2 and &thgr;3 are set so that cogging torque generated by the effective opening angle &thgr;2 of magnetic pole and cogging torque generated by the salient area opening angle &thgr;3 of magnetic pole are mutually in antiphase. Accordingly, a brushless DC motor capable of reducing cogging torque is realized.

Growing community of inventors

Aichi, Japan

Minoru Kitabayashi