Belt tensioner with vibration damping means

摘要

An auto-tensioner for applying tension to a transmission belt (9) by a tension pulley (8) and for damping reaction force acting from the belt. The tension pulley (8) is rotatably supported to a lever member (3) rotatably supported to a fixed pulley (1). A movable pulley (2) is provided on the lever member (3) at a position offset with respect to an axis of the tension pulley. An endless belt (4) is wound between a circular friction surface of the fixed pulley (1) and a circular friction surface of the movable pulley (2). An initial tension applying spring (5) forces to move the movable pulley (2) outward, thereby applying initial tension to the belt (4). When the movable pulley (2) is moved by reaction force acting on the tension pulley (8) from the transmission belt (9), damping force according to the reaction force is generated by grip generated between the belt (4) and respective pulleys (1,2) owing to change of tension between both spans (T1,T2) of the belt (4). <IMAGE>