| 摘要 |
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 angleθdetermined 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.
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