Power transmitting mechanism with silent chain and sprockets

Abstract

A power transmitting mechanism includes a first silent chain trained around teeth of a first driving sprocket and a teeth of first driven sprocket, and a second silent chain trained around teeth of a second driving sprocket and teeth of a second driven sprocket. The first and second driving sprockets are mounted in parallel relationship on a single drive shaft, and the teeth of the first driving sprocket are offset from the teeth of the second driving sprocket by one-half pitch. The pitch of the driving sprockets is a random pitch which varies in a random pattern along the circumference of the sprockets. The silent chains have a single pitch. By thus phasing the two driving sprocket, periodic meshing impact sounds emitted from the respective silent chains are canceled out or offset each other. The periodicity of the meshing impact sound is agitated by the random tooth pitch of the driving sprockets to such an extent that resonance sound is sufficiently reduced.