| 摘要 |
PROBLEM TO BE SOLVED: To provide a spring clutch having improved durability for preventing the breakage of a clutch spring due to fatigue. SOLUTION: Between a pulley 11 and a pulley hub 2 incorporated inside thereof, the cylindrical clutch spring 10 is incorporated in its diameter shrunk condition, whose cross section is formed of an angular rod material, so that the outer diameter face of the clutch spring 10 has elastic contact with a cylindrical clutch face 4 formed on the inner periphery of the pulley 1. A spiral portion 11 is provided at one end of the clutch spring 10, and the spiral portion 11 is inserted and fixed into a spiral groove 6 of the pulley hub 2. Rigidity is imparted to the spiral portion 11 to reduce torque input with elastic deformation due to the diameter enlargement ranging from the large diameter end to the opening end of the spiral groove 6. The diameter of the clutch spring 10 is enlarged during the rotation of the pulley 1 in one direction. When the diameter is enlarged, the diameter of the spiral portion 11 of the clutch spring 10 is enlarged to reduce sudden torque of the clutch. Thus, the spiral portion 11 is free from bending, resulting in the spring clutch having improved durability. COPYRIGHT: (C)2008,JPO&INPIT
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