| 摘要 |
Series of power transmission devices and geared motors are provided at low costs. The series of power transmission devices output input motive power via at least three pairs of gear sets. In the series of power transmission devices, a gear ratio of an intermediate stage gear set is changed without changing a gear ratio of a first stage gear set and a gear ratio of a final stage gear set in order to differ a speed increasing and reducing ratio on the whole device. |
