ELECTRIC MOTOR

PROBLEM TO BE SOLVED: To reduce torque ripple in a motor which is provided with magnets in the radial direction of an armature core while facing the same poles each other. SOLUTION: A pair of magnets 12 are arranged on the inner circumferential surface of a cylindrical yoke 3 incorporating a rotor 4 while facing the same poles each other, an iron pole portion 3a is formed between the magnets of the yoke, and an odd number of teeth 4d are provided on the rotor. Since an odd number of teeth are provided on the rotor for an even number of magnetic poles provided between magnets and adjoining magnets, no tooth exists on the 180 degree opposite side of the teeth facing a magnetic pole. Consequently, a phase in the torque waveform of each tooth is shifted and when the torque generated from respective teeth is totalized, the resulting torque is smoothed and torque ripple is reduced. COPYRIGHT: (C)2009,JPO&INPIT