PERMANENT MAGNET MOTOR

Japanese Patent JP3914293

B2

PROBLEM TO BE SOLVED: To reduce a cogging torque and eliminate vibration noise by a method wherein, in each pole of a permanent magnet, one of the layers of the permanent magnet is used as a reference layer and the same sides of the parts of the punched permanent magnet holes of the reference layer and the other layer are formed at positions shifted from each other by a specific angle.
SOLUTION: Permanent magnets 5 and 6 are provided in a rotor 1 while they are divided into two or more layers in the respective pole parts. In each pole part, one of the layers of the permanent magnet is used as a reference layer and the same sides of the parts of the punched permanent magnet holes 3, 4 of the reference layer and the other layer are formed at positions shifted from each other by an angle θ determined by a formula: θ=360/Ns×(n+i/Nm), 0<θ<360/(2P). In this formula, Ns denotes the number of stator slots, Nm denotes the number of layers of the permanent magnet in one pole parts, P denotes the number of poles, (i) denotes an integer from 1 to Nm-1 and (n) denotes an arbitrary integer. For instance, if each permanent magnet of a permanent magnet motor is divided into two layers in one pole part, the relative positions between the stator teeth and the respective layers of the permanent magnet are opposite to each other, so that a cogging torque can be reduced.

Nosei Asano
Masayuki Kondo
Hiroshi Ito
Yukio Honda
Hiroshi Murakami
Naoyuki Kakutani
Yokote Shizuka

JP345897A

May 16, 2007

January 13, 1997

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Matsushita Electric Industrial Co., Ltd

H02K1/27; H02K21/16; (IPC1-7): H02K1/27

JP8331783A
JP8336246A
JP8251847A
JP7336976A

Masaru Ishihara

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