To eliminate generation of an impact load in a belt when the rotating speed of the output side exceeds the rotating speed of the input side.
A pulley device having a built-in one-way clutch is composed of a pulley 7 rotating in a single piece with an outer ring 1, a bearing part 5 to support the outer ring 1 and an inner ring 2, a plurality of sprags 3 and a retainer 4 to retain them 3, and a resilient member 6 to energize the sprags 3, wherein the outer ring 1 is equipped with a plurality of segments 11 arranged in row along the circumferential direction and contacting with the sprags 3 and another resilient member 12 for outer ring positioned on the outside of the segments 11 and coupling them 11 with one another circumferentially, whereby movement of segments 11 in the radial direction is admitted by a restricting ring 21 rotating integrally with the pulley 7 while a relative circumferential movement of the restricting ring 21 and each outer ring segment 11 is restricted. In case an impact torque is applied from the input side, the resilient member 12 for outer ring makes elastic deformation to make gradual the rise of the torque and thereby precludes generation of an impact load.
SAITO TAKAHIDE
Torii Kazuhisa
Takayoshi Tagawa
Higashio Masahiro