Patent ID: 7503862

Claim:
A transmission comprising: a sliding mechanism having an inner member capable of rotating integrally with a rotation shaft, and an outer member arranged outside of the inner member in a radial direction thereof, the outer member being capable of rotating integrally with the inner member and of moving toward the inner member in an axial direction thereof; a first sprocket which moves integrally with the outer member; a plurality of second sprockets arranged in the axial direction thereof; a shifting mechanism which shifts a chain wrapped around the first sprocket from one sprocket to another among the plurality of second sprockets, the transmission in which, in response to movement of the chain in the axial direction thereof at the time when the shifting mechanism shifts the chain, the first sprocket moves in the axial direction thereof integrally with the outer member, the inner member including a guide surface by which the outer member is guided to move in the axial direction thereof, and the outer member provided with a dust cover separate from the outer member, the dust cover comprising a first cover and a second cover, the first sprocket being disposed therebetween and covering the guide surface in a radial direction thereof no matter what position in the axial direction thereof the outer member is at.