| 摘要 |
PROBLEM TO BE SOLVED: To provide an automatic transmission for shifting in response to a predetermined rotation quantity without depending on a user's intentional operation.SOLUTION: This automatic transmission has a hub unit 310 including a hub shaft 312 having an outside gear 324 and a hub shell for forming a third ratchet ring 372 and a second key projection on an inner peripheral surface, a first travel unit 330 including a driver 332 forming a second ratchet 342 on an outer peripheral surface and a driven sprocket 334 for rotating the driver, a second travel unit 350 including a third ratchet 358 for rotating the hub shell by meshing with the third ratchet ring and a carrier 352 attached with a plurality of planetary gears 356 rotating by meshing with the outside gear, and a conversion unit 370 including a ring gear having an inside gear 326 meshing with the planetary gears and a first key projection, and a bush arranged between the first key projection and a second key projection and transmitting torque from the driver to the carrier or the hub shell. |
