| 摘要 |
A planetary gear speed changer comprising an externally toothed wheel having external teeth (7A) in the form of a trochoidal curve and an internally toothed wheel having externally arranged pins to be internally meshed with the external teeth (7A) of the externally toothed wheel and eccentric with the externally toothed wheel, in which: the externally toothed wheel and internally toothed wheel swingably rotate while meshing with each other in an eccentric relation in such a manner that a phase shift equivalent to the number of tooth different between the both toothed wheels are caused for every swing and eccentric revolution as above, and revolution corresponding to the phase difference is taken out as output; specified relations are established among various factors including the radius of a pitch circle of an external pin (9), amount of eccentricity between the externally toothed wheel and internally toothed wheel, radius of an external pin (9), speed reduction ratio, difference in the number of teeth and so on, so that relative slip speed in tooth engagement when the number of tooth difference is more than two as well as noise may be reduced; and, further, the same external pin is adapted to be commonly applicable to three external teeth or more by setting the radius of an external pin to a specified value and the number of said pins to a specified one. |
