| 摘要 |
PURPOSE:To reduce an armature reaction without increasing the size by reducing the thickness between the outer and inner peripheral surfaces of a yoke to the minimum near a position passing the center of a pole and noncontacting the inner periphery of the yoke with a supporting shaft. CONSTITUTION:The outer peripheral surface of a yoke 6 is formed in a cylindrical surface, and permanent magnets 2-5 are secured by an adhesive at an equal interval on the outer periphery in the circumferential direction. The inner periphery of the yoke 6 is punched in a start shape to provide air gaps 7, and a supporting shaft 8 is passed without contact with the yoke 6 in the air gap 7. The thickness between the outer periphery of the cylindrical surface of the yoke 6 and the inner periphery of the star shape alters in response to the disposition of the magnets 2-5, and is formed in the minimum thickness at the position passing the center C of the pole formed of the magnets 2-5. The maximum thickness is formed at the intermediate position of the adjacent magnets 2-5. |
