摘要 |
A dynamic balance is improved in an S-P-C type planetary gear mechanism. An input shaft is fixed to a disk, and an output shaft is fixed to a planetary gear. A circular recess is formed in the disk so as to be eccentric to the input shaft. A ring gear engaged with the planetary gear is rotatably supported by the circular recess. A weight-reduced portion having the same depth as that of the recess is provided in a part of the disk where the circular recess is not formed, and a weight portion is formed to recover the axial dynamic balance of the disk, which is lost by arranging the circular recess and the ring gear. Since the planetary gear is fixed coaxially to the output shaft, 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.
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