| 摘要 |
The field magnet is formed of, for example, two permanent magnets, and a width of the field magnet increases from a center toward both ends thereof in a monotonically non-decreasing manner. The field magnet includes, at the both ends thereof, projecting portions projecting to a side opposite to a rotation axis. The field core includes a penetration hole through which the field magnet is caused to penetrate. The penetration hole includes penetration surfaces which cover magnetic pole surfaces of the field magnet, respectively. Specifically, the penetration surface includes concave portions with which the projecting portions are fitted. When the field magnet is inserted, the penetration surfaces serve as a guide which guides the field magnet, and accordingly the field magnet can be caused to penetrate through the penetration hole with ease.
|
