Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: An autotensioner comprises a cup-shaped stationary member, an arm rotatably attached to an opening of the stationary member. An axial bore is formed in the bottom of the stationary member. A rocking wall extending to the bottom is provided at the arm. A first friction member is provided between the rocking wall and the inner wall of the opening. The first friction member is gripped between the rocking wall and the inner wall. A rocking shaft extending to the bottom is provided at the center of a lid portion of the arm. The rocking shaft is inserted in the axial bore. A second friction member is provided between the rocking shaft and the axial bore. The first friction member and the second friction member are formed of a synthetic resin mainly comprised of PPS, exhibit high limited PV factors, and exhibit low coefficients of friction.

Abstract: An autotensioner comprises a cup-shaped stationary member, an arm rotatably attached to an opening of the stationary member. An axial bore is formed in the bottom of the stationary member. A rocking wall extending to the bottom is provided at the arm. A first friction member is provided between the rocking wall and the inner wall of the opening. The first friction member is gripped between the rocking wall and the inner wall. A rocking shaft extending to the bottom is provided at the center of a lid portion of the arm. The rocking shaft is inserted in the axial bore. A second friction member is provided between the rocking shaft and the axial bore. The first friction member and the second friction member are formed of a synthetic resin mainly comprised of PPS, exhibit high limited PV factors, and exhibit low coefficients of friction.

Abstract: An autotensioner having a support shaft affixed to a base, and a cup of a swing member provided swingably about the support shaft. The cup opens to the base and houses inside it a torsion coil spring for biasing the pulley in the direction tensioning the belt. A damping member braking the swing member is fixed to the base. A ring-shaped spring brings it into close contact with the inner circumferential surface close to the opening of the cup. The damping member frictionally slides with the inner circumferential surface at the time of swing of the swing member and supports the swing member in the radial direction at the base side from the bearing supporting the support shaft.

Abstract: An autotensioner comprises a torsion coil spring interposed between a base and a rocking arm, and a tubular bushing provided between an inside surface of the base and an outside surface of the rocking arm. The torsion coil spring pushes and biases the rocking arm toward the bushing, and brings the pushing direction substantially in coincidence with the axial load direction of the force, acting on a stepped bolt supporting the rocking arm, from a belt. When the belt tension becomes high, the arm axial center displaces slightly from the base axial center, an extremely large first damping force acts on the rocking arm. When the belt tension becomes low, the smaller second damping force acts on the rocking arm.

Abstract: An autotensioner comprises a support shaft affixed to a base, and a cup of a swing member provided swingably about the support shaft. The cup opens to the base and houses inside it a torsion coil spring for biasing the pulley in the direction tensioning the belt. A damping member braking the swing member is fixed to the base. A ring-shaped spring brings it into close contact with the inner circumferential surface close to the opening of the cup. The damping member frictionally slides with the inner circumferential surface at the time of swing of the swing member and supports the swing member in the radial direction at the base side from the bearing supporting the support shaft.

Abstract: The tensioner comprises a cup fixed to an engine block and a pivot shaft which is fixed to a bolt engagement portion of the cup. The pivot shaft is inserted into a pivot bearing, and an arm is pivotally attached to the pivot shaft. The arm is biased by a torsion coil spring to rotate in a direction tensioning the belt. A sleeve having an axially extending slit is attached to an outer surface of the bolt engagement portion. One end of a coil spring is wound around the pivot bearing, and the other end is wound around the sleeve. The coil spring and the sleeve minutely deform by the rotation of the arm to generate a damping force. A damping force acting upon the arm when tensioning the belt is smaller than the damping force acting upon the arm when the belt is loosened.

Abstract: A belt tensioner has a tensioner and a tensioner arm. The tensioner cup has an opening, and the tensioner arm has a lid portion formed at one end. The lid portion is rotatably connected to the cup and extends so as to close the opening thereof. The tensioner also has a torsion spring provided in the cup to act between the cup and the arm so as to elastically urge the arm in a rotational direction. A damping member is secured to the lid portion of the arm such that an outer circumferential surface of the damping member is in sliding contact with an inner circumferential surface of the cup. Further, the tensioner has a ring-like spring provided in the damping member so as to elastically urge the damping member against the inner circumferential surface of the cup. The lid portion of the arm has at least two columnar pin-like elements protruding therefrom parallel with a swing axis of the lid portion of the arm, and the columnar pin-like elements are inserted in holes formed in the damping member.

Abstract: A belt tensioner having a tensioner arm swingably connected to a stationary member about a swing shaft and a belt engaging member for engaging a belt and rotatably arranged at the tensioner arm. A first urging member urgings the tensioner arm rotationaly around the swing shaft so that the belt engaging member tensions the belt. A damping member arranged between the stationary member and the tensioner arm so that friction is produced between the stationary member and the damping member in order to damp a swinging motion of the tensioner arm when the tensioner arm swings. A second urging member urges the damping member toward the stationary member or vice versa in order to produce the friction.