| 摘要 |
PROBLEM TO BE SOLVED: To provide an electric motor or a power generator whose total cogging torque is drastically reduced and cost increase is suppressed. SOLUTION: The electric motor includes: a rotor 3 including a yoke 6 rotating with a rotary shaft in one body and having an outer circumference surface or an inner circumference surface on which a predetermined number of permanent magnet groups 7 each consisting of a single solid body where a predetermined number of magnetic poles are alternatively expressed are arranged in a circle at equal intervals; and a stator 2 having an inner circumference surface or an outer circumference surface facing the arrangement plane of the permanent magnet groups 7 of the rotor 3, on which a predetermined number of coil winding portions 4 are arranged in a circle at equal intervals. The number of the magnetic poles, the number of the permanent magnet groups 7 and the number of the coil winding portions 4 are so chosen that a number of pulsations per rotation of cogging torques each generated between the contiguous magnetic poles in the permanent magnet group 7 and a number of pulsations per rotation of cogging torques each generated between the contiguous permanent magnet groups 7 are same, and a dimension H of gaps each formed between the contiguous permanent magnet groups 7 is so chosen that directions of the former cogging torques and those of the latter cogging torques are opposite mutually. COPYRIGHT: (C)2009,JPO&INPIT
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