A torsional coupling including parts that all work together. Torque is applied to the inner member. The first stage (low torque) consists of a bonded part (rubber, inner and outer member) that is in series with a set of compression style coil springs. The torsional stiffness of the bonded part is approximately 25% of the resulting torsion stiffness provided by the coil springs. The second stage (high torque) the tangs on the inner member engage with a sprocket plate which locks out the first stage and transfers all torque through the coil springs. The coil springs are held in place by a unique geometry on the sprocket plate and the spring holders. The spring holders also prevent metal to metal contact between the coil springs and the upper and lower housing portions. Surface effect damping occurs at very high torques when the rubber molded around the tangs on the inner member rub on the bumps on the lower housing portion. A thrust bearing is used to react axial forces and to eliminate any metal to metal contact.

A damper disc assembly includes an input plate, an output unit including an input-side member and an output-side member, a high stiffness damper unit, a low stiffness damper unit and first and second hysteresis torque generating mechanisms. The low stiffness damper unit is disposed axially between the input plate and the input-side member, and is actuated in a low torsion angular range of torsional characteristics. The first hysteresis torque generating mechanism generates a first hysteresis torque in a lower torsion angular part of an actuation range of the low stiffness damper unit. The second hysteresis torque generating mechanism generates a second hysteresis torque in a higher torsion angular part of the actuation range of the low stiffness damper unit and an actuation range of the high stiffness damper unit.

A clutch assembly is disclosed that includes a hub, a damper and a pre-damper. A first pre-damper side plate is adjacent the damper and a second pre-damper side plate has a lug that extends radially outwardly and axially across the intermediate plate and the first pre-damper plate toward a first side plate of the damper that is adjacent the pre-damper. The lug is received in a notch defined by the first side plate of the damper to prevent relative rotation between the first side plate of the damper and the pre-damper. A method is disclosed for assembling the pre-damper and the damper on a hub. The pre-damper includes a radially and axially extending lug that is assembled to the notch in the damper to prevent relative rotation between the damper and the pre-damper.

Torque is applied to an inner member of a torsional coupling. The first stage (low torque) has a bonded part in series with a set of compression style coil springs. The torsional stiffness of the bonded part is approximately 25% of the resulting torsional stiffness provided by the coil springs. In the second stage (high torque), tangs on the inner member engage with a sprocket plate, transferring torque to the coil springs. The coil springs are held in place by a unique geometry on the sprocket plate and spring holders, which prevent metal-to-metal contact between the coil springs and upper and lower housing portions of the torsional coupling. Surface effect damping occurs at very high torques when the rubber molded around the tangs on the inner member rub on bumps formed on the lower housing portion. A thrust bearing reacts axial forces and eliminates metal-to-metal contact.

A damper disc assembly includes an input plate, an output unit including an input-side member and an output-side member, a high stiffness damper unit, a low stiffness damper unit and first and second hysteresis torque generating mechanisms. The low stiffness damper unit is disposed axially between the input plate and the input-side member, and is actuated in a low torsion angular range of torsional characteristics. The first hysteresis torque generating mechanism generates a first hysteresis torque in a lower torsion angular part of an actuation range of the low stiffness damper unit. The second hysteresis torque generating mechanism generates a second hysteresis torque in a higher torsion angular part of the actuation range of the low stiffness damper unit and an actuation range of the high stiffness damper unit.