| 摘要 |
PROBLEM TO BE SOLVED: To provide an inscribed gearing type planetary gear mechanism which can be improved in durability by increasing a torque transmission capacity while keeping its compact size, and further improved in transmission efficiency.SOLUTION: An inscribed gearing type planetary gear mechanism includes an internal gear and an external gear. In the mechanism, there are set an external tooth creation ellipse 146 having a center 136-1 on an internal tooth real pitch circle 124 having a radius larger than an internal tooth theoretical pitch circle 122 by a prescribed amount, having an ellipticity of less than 1 and having a short axis in the normal direction, and an internal tooth creation ellipse having the same center as the external tooth creation ellipse 146 and having a minor axis and a major axis slightly smaller than those of the external tooth creation ellipse 146. The external gear is formed into a tooth shape composed of an inner contour line 152 of a region 150 where the external tooth creation ellipse 146 passes when the internal tooth theoretical pitch circle 122 is rotated together with the external tooth creation ellipse 146 on the external tooth theoretical pitch circle 142, and the internal gear has an addendum shape including an inner part of the internal tooth real pitch circle 124 of the internal tooth creation ellipse. |
