| 摘要 |
PROBLEM TO BE SOLVED: To provide a gear box that can be miniaturized, in comparison to the conventional one and provided with a sufficient reduction gear ratio by realizing the constitution of a planetary gear mechanism, proving no hindrance to action and assembly, even if setting the tooth profile of each gear to a small module in order to miniaturize the gear mechanism. SOLUTION: The number of teeth for a sun gear 12b is set to e=9, the number of teeth of first gear parts 13a of three planetary gears is set to respectively z1=15, the number of teeth of second gear parts 13b is set to z2=18, the number of teeth of a fixed internal gear is set to I1=42, and the number of teeth of a movable internal gear is set to I2=51. The reduction gear ratio obtained according to equation (1) is 481. The numbers of teeth e, z1, z2, I1, I2 are all multiples of 3, and the difference between z1 and z2, and the difference between I1 and I2 are also multiples of 3.
|
