| 摘要 |
<p>A dynamic balance is improved in an S-P-C type planetary gear mechanism (8). An input shaft (9) is fixed to a disk (13), and an output shaft (10) is fixed to a planetary gear (12). A circular recess (13a) is formed in the disk (13) so as to be eccentric to the input shaft (9). A ring gear (11) engaged with the planetary gear (13) is rotatably supported by the circular recess (13a). A weight-reduced portion (13b) having the same depth as that of the recess (13a) is provided in a part of the disk (13) where the circular recess (13a) is not formed, and a weight portion (W) is formed to recover the axial dynamic balance of the disk (13), which is lost by arranging the circular recess (13a) and the ring gear (11). Since the planetary gear (12) is fixed coaxially to the output shaft (10), it does not perform an eccentric motion and thus secures the dynamic balance thereof. Accordingly, the dynamic balance in the axial direction is secured for every individual rotating element constructing a gear device (8). <IMAGE></p> |
