| 摘要 |
PROBLEM TO BE SOLVED: To provide a more silent drive unit equipped with a planetary gear train.SOLUTION: A planetary gear train includes a first sun gear driven by a motor, a first ring gear, a first carrier, and a plurality of planetary gears arranged on one side of the first carrier and meshed with the first sun gear and the first ring gear. The first sun gear, the first planetary gears and the first ring gear are helical gears so as to increase the meshing surface. Helical teeth formed on the inner surface of the first ring gear are meshed with the helical teeth of the first planetary gears. The operation is therefore stable, and noise is reduced. The planetary gears are made of plastic to further decrease the noise. The first ring gear is made by sintered powder metallurgy. |
