| 摘要 |
PURPOSE:To reduce core loss generated on a return yoke itself, by forming a plurality of space sections on a ringformed return yoke set over all the surface of a stationary housing. CONSTITUTION:At the end section of a rotary shaft 3, a discformed rotor yoke 4 is integrally fixed, and on the lower surface of the rotor yoke 4, a ring-formed magnet 5 is integrally fitted. On the upper surface of a stationary housing 1, a ring-formed return yoke 6 is fixed and fitted. The return yoke 6 is made of the band-formed metallic unit 6 a of one steel sheet, and is wound up in an eddy shape from its start end 6aA to its final end 6aB, and a plurality of space sections 8 are formed in the circumferential direction. On the rotational movement of the rotor yoke 4, the core loss of the return yoke 6 itself can be reduced by a plurality of the space sections 8 of the return yoke 6, and also on the high speed rotation, the generation of the core loss is extremely reduced, and the characteristic of stable rotation can be obtained. |
