| 摘要 |
A magnetic resistance changing mechanism for changing a magnetic resistance of a stator magnetic path including a stator yoke portion 50 and each tooth portion 30 by mechanically changing the stator magnetic path is provided. A pair of side protruded portions 31a, 31a are formed on circumferential sides of a rotor side end portion of each tooth portion 30. The rotor side end face of each tooth portion 30 is shaped so that a gap between the rotor side end face of each tooth portion 30 and an outer periphery of the rotor 102 is increased continuously or stepwisely from a circumferential intermediate portion of the rotor facing end face toward circumferential end portions thereof. |
