US Patent 7425181 Torque fluctuation absorbing device

A torque fluctuation absorbing device includes a first rotational member which transmits a torque from a driving power source, a damping mechanism connected with an input shaft of a transmission, the damping mechanism having a pair of frictional members of approximately annular-shaped fixed at both surfaces of a disc, and a limiter portion for frictionally engaging the pair of frictional members with the first rotational member in a substantially direct manner or in a substantially indirect manner via a pair of frictional plates. An actual length of at least one of the pair of frictional members ranges substantially between 1 percent and 6 percent of a major diameter of the at least one of the pair of frictional members.