| 摘要 |
PROBLEM TO BE SOLVED: To provide a speed change gear having a large transfer ratio, a short axial structural length, and a small rotary play, and capable of being inexpensively manufactured. SOLUTION: The epicycloidal speed change gear is provided with a sun gear 4 driven by a driving engine, an internal gear 12 arranged in housing 8, 10, a first planetary gear 16 group, and a secondary planetary gear 18 group. The secondary gear 18 is formed as a stepped planetary gear provided with a small gear 22 and a large gear 20. The large gear 20 of the stepped planetary gear meshes with the sun gear 4, the small gear 22 of the stepped planetary gear meshes with a pair of adjacent first planetary gears 16, and the first planetary gear 16 meshes with the internal gear 12. The planetary gear carrier 14 has an opening at the driving engine side, and the large gear 20 of the stepped planetary gear is axially inserted through the opening when it is assembled. The first planetary gear 16 and the stepped planetary gear 18 are completely arranged inside the deddendum circle of the internal gear 12 in the radial direction. |
