| 摘要 |
<p>Realized is a reduction gear mechanism, in which a total reduction ratio is adjusted to a desired value without changing a rotational direction changing gear mechanism and a reduction unit. The rotational direction changing gear mechanism comprises an input gear for rotating integrally with an input shaft, and a relay gear meshing substantially at a right angle with the input gear. A reduction ratio adjusting gear mechanism includes a first spur gear for rotating integrally with the relay gear, a second spur gear meshing with the first spur gear, and a third spur gear meshing with the second spur gear. The reduction unit includes a crankshaft for rotating integrally with the third spur gear and for rotating an eccentric cam eccentrically, an external gear for revolving in engagement with the eccentric cam, an internal gear meshing around and with the external gear and having a tooth number different from that of the external gear. This reduction gear mechanism is enabled to change its total reduction ratio by replacing at least one of the first spur gear, the second spur gear and the third spur gear, by another gear having a different tooth number.</p> |
