Silent chain power transmission device

Abstract

The present invention is directed to decreasing noise from the onset of engagement with the sprocket teeth till seating thereon and also to reducing wear to the silent chain and the sprocket. A face (a) of a sprocket tooth, which contacts the chain at the onset of engagement, has a tooth profile that is an envelope () of trajectories described by the inner flank surface () of the link plate () when the chain moves linearly toward the sprocket (S) and engages with the sprocket (S) without causing a chordal action. A crest (b) of the sprocket tooth, which contacts the chain (S) at the time of seating on the sprocket tooth, has a tooth profile that is an envelope (m) of trajectories described by the crotch () of the link plate () when the link plate () rotates around the connecting pin during the wrapping motion of the chain around the sprocket (S). A connecting surface (c) that connects the face (a) of the sprocket tooth with the crest (b) is formed of a curved surface which is inscribed in the envelope () of the trajectories during the linear motion of the link plate and the envelope (m) of the trajectories during the rotational motion of the link plate.