PURPOSE: To transmit torque, input to an input part side, to an output part side at high efficiency of power transmission by surely impeding transmission of torque to the input part side from the output part side.
CONSTITUTION: A drum gear 7, rotated with an input shaft l, first/second drums 6, 9 and outer rings 10, 11 are coaxially arranged in a housing 3, to respectively bring into friction contact one ends of coil springs 19, 20 with outer rings 10, 11, the other ends with the drum gear 7 and the intermediate parts with fixed rings 15, 16. In the coil springs 19, 20, in the case of inputting torque from a side of an output shaft 2, the outer rings 10, 11 are connected to the fixed rings 15, 16 to lock rotation of the outer rings 10, 11, and only in the case of inputting the torque from a side of the input shaft l, the fixed rings 15, 16 are unlocked to connect the first/second drums 6, 9 to the drum gear 7.
ICHIKAWA TOSHIRO
KINO MASAHIRO
