| 摘要 |
PROBLEM TO BE SOLVED: To provide an auto tensioner to reduce internal heating or wearing resulting from a small tension change of a transmission belt owing to fluctuation in the rotation of an automobile engine. SOLUTION: The auto tensioner is provided with a pulley 5 installed in an arm of a movable member 4 and capable of being in contact with the belt, a coil spring to urge the movable member 4 in the predetermined direction for a housing material, and a cylindrical friction material 9 disposed between the movable member 4 and the housing material to attenuate the oscillation of the movable member 4. A key groove 30 is carved in a face opposite to the friction material 9 of the movable member 4. A key 31 circumferentially fitted with clearance to the key groove 30 is projected in the other end. The friction coefficient of the outer peripheral surface of the friction material 9 is set less than the friction coefficient of the inner peripheral surface. Unless the key 31 is brought in contact with the key groove 30, the outer peripheral surface having a small friction coefficient is slid. When the key 31 is brought in contact with the key groove 30, the inner peripheral surface having a large friction coefficient is slid. COPYRIGHT: (C)2007,JPO&INPIT
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