| 摘要 |
A transmission unit includes a planetary gearing system including a ring gear connected to a bicycle frame, a planet carrier with planet gears, and at least one sun gear that is engaged with the planet gears. A rear wheel shaft is coaxial with respect to the sun gear. A driving mechanism is operatively rotationally engaged with the planet carrier. At least one bearing is configured to bear the rear wheel shaft with respect to the bicycle frame and is arranged between the planetary gearing system and a seat of the rear wheel from an axial perspective. The bearing bears the rear wheel shaft inside from a radial perspective and is connected, either directly or indirectly, to the bicycle frame, externally from a radial perspective. The transmission unit provides at least one transmission ratio between a driving mechanism and the rear wheel shaft. |
