To prevent the breakage of a clutch spring caused by fatigue.
The clutch spring 6 is incorporated between a pulley 1 and a pulley hub 2 so that the outer peripheral face of the clutch spring 6 is put in elastic contact with the inner peripheral face 5 of the pulley 1. On the outside of the pulley hub 2, there are provided an input ring 8 to which the rotation of the pulley 1 is transmitted via the clutch spring 6, an output ring 9, and an elastic member 10 for energizing the output ring 9 toward the input ring 8. The input ring 8 is supported rotatably and immovably in the axial direction. The output ring 9 is prevented from being rotated by the pulley hub 2 and supported movably in the axial direction. A torque cam means 20 is incorporated between opposed faces of the input ring 8 and the output ring 9. During the rotation of the input ring 8 relative to the output ring 9, the operation of the torque cam means 20 moves the output ring 9 in the direction of leaving the input ring 8 to give elastic deformation to the elastic member 10. The elastic deformation of the elastic member 10 absorbs an impact during transmitting torque to prevent the breakage of the clutch spring 6.
SAITO TAKAHIDE
Torii Kazuhisa
Takayoshi Tagawa
Higashio Masahiro