To provide a spring clutch excellent in durability capable of preventing a clutch spring from breaking by fatigue.
The cylindrical clutch spring 10 comprising a wire rod having a square cross section is assembled between a pulley 1 and a pulley hub 2, and the outer periphery of the clutch spring 10 is brought into elastic contact with a clutch face 4 on the inner periphery of the pulley 1. A spring fitting recessed part 6 is formed at an end of the outer periphery of a flange 5 provided to one end of the pulley hub 2, and a side face 6a of the spring fitting recessed part 6 is made to be inclined along an inclined side face of a coil part 10a. The spring fitting recessed part 6 is provided with a torque transmission face 6b on which an end face of the coil part 10a abuts. A locking plate 8 for preventing movement of the clutch spring 10 in the axial direction is mounted on the other end of the pulley hub 2. The clutch spring 10 is increased in diameter over the entire length in the axial direction and formation of bending is prevented. Rotation of the pulley 1 is transmitted to the pulley hub 2 from an end face of the coil spring 10a constantly held in an abutted state with the torque transmission face 6b.
COPYRIGHT: (C)2008,JPO&INPIT
NAKAKOJI MASAFUMI
Torii Kazuhisa
Takayoshi Tagawa
Higashio Masahiro
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