| 摘要 |
PURPOSE:To smoothly rotate a rotor by a method wherein an attractive force effecting action upon a field magnet of the rotor magnetized in the axial direction and a yoke on the side where an armature winding is provided is made smaller than the attractive force acting upon the yoke on the side where the armature is not provided. CONSTITUTION:A rotary shaft 3 attached with the field magnet 4 magnetized for multipoles in the axial direction is pivotally supported with a bearing 2 of a case 1-1, and a magnetic yoke 5 provided with the armature winding 6 on the upper surface of the field magnet 4 through the 1st space and a magnetic yoke 8 on the lower surface through the 2nd space respectively are received in the case 1-1. And the attractive force which effects action upon the field magnet 4 and the magnetic yoke 5 is made smaller than that acting upon the field magnet 4 and the magnetic yoke 8. For example, the length of the 1st space is made larger than that of the 2nd space. Whereby, when the output of the rotary shaft 3 is taken out of the magnetic yoke 5 side, the rotary shaft 3 may always push a thrust bearing 7 provided on the magnetic yoke 8 side by almost a poit contact, thereby enabling to obtain the smooth rotation. |
