Patent ID: 8641563

Claim:
A belt pulley damper for attenuating torsional vibrations of a drive shaft of a motor vehicle engine, said damper comprising: a belt pulley for driving a pulling device, a drive flange spaced axially from an inner radial surface of the belt pulley and nonrotatably connected with the drive shaft, a torsional vibration damper connected with the drive flange for damping torsional vibrations introduced from the drive shaft, wherein the torsional vibration damper includes a drive disk axially movable relative to the drive flange, and a driven disk axially adjacent to and axially movable relative to the belt pulley, wherein the belt pulley includes at least one belt pulley tooth on the inner radial surface and axially facing the driven disk, and the driven disk includes at least one driven disk tooth axially facing the inner radial surface of the belt pulley, wherein the at least one belt pulley tooth and the at least one driven disk tooth are engaged below a threshold pull force acting on the belt pulley and occurring during drive operation of the drive shaft during which operation power flows from the drive shaft to the belt pulley, and are disengaged above the threshold pull force during drive operation of the drive shaft, and wherein the belt pulley tooth and the driven disk tooth are engaged below a threshold push force acting on the belt pulley and occurring during coasting operation during which no torque is transmitted by the drive shaft to the belt pulley and power flows from the belt pulley toward the drive shaft, and are disengaged above the threshold push force during coasting operation.