Abstract: To provide a simple-structured chain drive mechanism that can reduce the noise generated when the chain sits on the sprocket, prevent deterioration of power transmission efficiency, and retard the progress of wear on the sprocket or chain. The chain drive mechanism includes a sprocket having a plurality of teeth, and a chain having a plurality of link plates and configured to be put around the sprocket. The sprocket includes a pair of flanges protruding circumferentially around the sprocket such as to sandwich the plurality of teeth from sides. The chain includes a pair of seat portions on both sides of the chain so that the flanges abut on the seat portions from a circumferential direction of the sprocket when the chain sits.

Abstract: To provide a simple-structured chain drive mechanism that can reduce the noise generated when the chain sits on the sprocket, prevent deterioration of power transmission efficiency, and reduce wear of the sprocket and chain. The chain drive mechanism includes a rotating shaft, a sprocket having a shaft hole, and a chain. The shaft hole is provided with a rotation transmitting groove on an inner circumferential surface thereof. The rotating shaft is provided with a rotation transmitting member that engages with the rotation transmitting groove. The rotation transmitting member is configured to be capable of relative sliding movement at least in a circumferential direction of the rotating shaft and capable of restoring relative positions of the rotating shaft and the sprocket.

Abstract: To provide a simple-structured chain drive mechanism that can reduce the noise generated when the chain sits on the sprocket, prevent deterioration of power transmission efficiency, and retard the progress of wear on the sprocket or chain. The chain drive mechanism includes a sprocket having a plurality of teeth, and a chain having a plurality of link plates and configured to be put around the sprocket. The sprocket includes a pair of flanges protruding circumferentially around the sprocket such as to sandwich the plurality of teeth from sides. The chain includes a pair of seat portions on both sides of the chain so that the flanges abut on the seat portions from a circumferential direction of the sprocket when the chain sits.