| 摘要 |
A gear shifting apparatus that automatically performs gear shifting in response to a load is constituted by a small number of components. The gear shifting apparatus includes an output shaft coupled to a carrier of a planetary gear shifting mechanism, an operating ring that rotates relative to a ring gear of the planetary gear shifting mechanism, and a coil spring that biases the ring gear and the operating ring so as to maintain their relative rotational orientations in neutral orientations. The apparatus further includes an operating member that couples the ring gear and the carrier to each other when the relative rotational orientations of the ring gear and the operating ring are the neutral orientations, and fixes the ring gear and allows rotation of the carrier when the relative rotational orientations come off the neutral orientations. |
