| 摘要 |
PROBLEM TO BE SOLVED: To make it possible to obtain a higher speed reduction ratio and to increase a maintenance performance without enlarging a size of a device.SOLUTION: Screw grooves 121a, 161a are provided between a peripheral surface of a first front stage outer gear 12, which becomes a stationery side of a front stage wondrous gear mechanism 10 and a peripheral surface of a front stage housing 16, the first front stage outer gear 12 and the front stage housing 16 are engaged with each other by the screw grooves 121a, 161a, screw grooves 162a, 222b are provided between a peripheral surface of a first latter stage outer gear 22, which becomes a stationery side of a latter stage wondrous gear mechanism 20 and the peripheral surface of the front stage housing 16, the first latter stage outer gear 22 and the front stage housing 16 are engaged with each other by the screw grooves 162a, 222b, screw grooves 222a, 261a are provided between a peripheral surface of a latter stage housing 26 and a peripheral surface of the first latter stage outer gear 22, and the latter stage housing 26 and the first latter stage outer gear 22 are engaged with each other by the screw grooves 222a, 261a. |
