| 摘要 |
<P>PROBLEM TO BE SOLVED: To obtain a structure capable of reducing a cogging torque by arranging ferrite magnets radially. <P>SOLUTION: A rotation part 3A of a motor 1A has a core rotor having a plurality of core pieces 51A, and a plurality of magnets 52A. The plurality of core pieces 51A and the plurality of magnets 52A are arrayed alternately in a peripheral direction. A radially outer surface of a core piece 51A has a small-diameter surface 512A and a large-diameter surface 511A larger in distance from a center axis than the small-diameter surface. When such a configuration is employed, a motor having small cogging torque is obtained only by suitably setting extent and arrangement of the large-diameter surface 511A. Further, the large-diameter surface 511A is arcuate having its center at the center axis on a section orthogonal to the center axis. Consequently, the whole large-diameter surface can be put close to teeth 412A, and magnetic flux density between the teeth 412A and the large-diameter surface 511A can be increased. <P>COPYRIGHT: (C)2013,JPO&INPIT |
