| 摘要 |
PROBLEM TO BE SOLVED: To provide a spring clutch which can prevent a breakage of a clutch spring due to fatigue, and is excellent in its durability. SOLUTION: A cylindrical clutch spring 6 is assembled between a pulley 1 and a pulley hub 2. The outer periphery of the clutch spring 6 is brought into elastic contact with the clutch surface 4 formed on the inner periphery of the pulley 1. A projecting portion 7 is provided on the outer periphery of the flange 5 formed on the pulley hub 2 so as to circumferentially oppose to the torque output side end portion of the clutch spring 6. Thus, the pulley hub 2 is turned in the same direction as that of the pulley 1 by transmitting the rotation of the clutch spring 6 to the projecting portion 7. A large diameter hole 8 is formed on the clutch surface 4. The torque output side end portion of the clutch spring 6 is covered by an elastic ring 10 capable of expanding its diameter in the large diameter hole 8 so as to supplement the stiffness of the torque output side end portion of the clutch spring 6. Thus, the formation of bent portion on the torque output side end portion of the clutch spring 6 can be prevented in the case of transmitting a torque to make the diameter of the clutch spring 6 expand. As a result, the breakage of the clutch spring 6 due to fatigue can be prevented. COPYRIGHT: (C)2008,JPO&INPIT
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