| 摘要 |
PURPOSE:To reduce the bearing loss, shorten the total length and permit to miniaturize the device by a method wherein a boss, integral with the shaft of a planetary gear, is projected to the side of an armature while the boss is supported to a center bracket through a bearing. CONSTITUTION:The boss section 6b, having L-shape in section, is secured integrally to the end 6a of the shaft 6 of the planetary gear 5 and the outer periphery thereof is supported to the center bracket 4, whose one part is arranged between the armature coil end 7a of the armature 7 and an armature shaft 1, through the bearing 2 while an output rotary shaft 3 is supported by a housing 10 and the center bracket 4 through bearings 3a, 2. Thus, the part supporting the boss section 6b of the center bracket 4 is located at the inside of the armature coil end 7a, therefore, the total length of the device may be shortened. On the other hand, the rotating speed of the boss section is lower than the rotating speed of the armature 1 after the planetary gear type speed reduction by a value corresponding to the reduction ratio thereof, therefore, the bearing loss due to the bearing 2 is small and the service life of the bearing 2 may be secured. |
