| 摘要 |
<p>PURPOSE:To surely fix a rotary body and to make it thin by providing plural protrusions on the peripheral surface of a magnet and also providing engaging parts whereby the protrusions are engaged in the peripheral direction corresponding respectively to the protrusions, on the rotary body rotated with a hub shaft. CONSTITUTION:The rectangular protrusions 14 are provided on plural positions on the peripheral surface of the ring-like magnet 12, and the protrusions 14 are located at the side lower than the intermediate part in the direction of the thickness of the magnet 12 and projectingly provided. On transmission gears 8,9 as the rotary body whereon the magnet 12 is mounted, fixed pieces 15 are erected at the upper side corresponding respectively to the protrusions 14. When the magnet 12 is mounted on the gears 8, 9, the protrusions 14 are placed on the gears 8, 9 at first in such a manner that the magnet 12 is inserted to the inner sides of each fixed piece 15 in the corresponded state between the fixed pieces 15. By turning the magnet 12 to the peripheral direction under this state, the protrusions 14 are inserted to the engaging parts 16 of the fixed pieces 15 and engaged therewith. Thus, the magnet 12 is surely fixed and held, then never easily fallen off.</p> |
