Patent ID: 7241224

Claim:
A torsional vibration damper, comprising: a primary mass adapted to be coupled to an engine crankshaft for rotation about a rotational axis of the engine crankshaft, the primary mass defining a substantially ring-shaped chamber that is divided into at least two portions; a secondary mass relatively rotatably connected to the primary mass and connectable with a clutch; and a damping unit for coupling the primary and secondary masses to each other in a rotationally elastic manner, wherein the damping unit comprises: a plurality of coil springs situated in series and disposed one after the other within the divided portions of the ring-shaped chamber, a pair of end guides slidably disposed within each divided portion of the ring-shaped chamber and supporting outer ends of the coil springs among the plurality of elastic members, and a friction member slidably disposed between neighboring coil springs and configured to be rubbed against at least one of an inner wall and an outer wall of the ring-shaped chamber in response to compressions of the coil springs such that a friction force is generated in proportion to a relative rotation between the primary and secondary masses as well as to a rotational speed thereof, wherein the friction member comprises: a concentrated mass; an outer wedge-shaped friction guide elastically supported by one of the neighboring coil springs toward the concentrated mass and provided with a first slanted surface contacting the concentrated mass at one end thereof; and an inner wedge-shaped friction guide elastically supported by the other of the neighboring coil springs toward the concentrated mass and provided with a second slanted surface contacting the concentrated mass at one end thereof; wherein the concentrated mass is disposed such that the outer wedge-shaped friction guide moves radially outward and the inner wedge-shaped friction guide moves radially inward.