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US 6,264,578 B1Granted
Belt tensioner with vibration damping function
AssigneeUnitta Company
InventorKazumasa Ayukawa
Life of this patent
Estimating the term…
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.
Claims23
A tensioner comprising:
- a fixing member that includes a first boss;
- an arm that includes a second boss, coaxially arranged with respect to said first boss, and a pulley attached to an end portion of said arm, said arm being rotatable between a first rotation position and a second rotation position around said second boss;
- a biasing member that urges said arm in a first direction from said second rotation position toward said first rotation position so as to tension a belt via said pulley;
- and
- a damping member that includes a first coil spring having two end portions engaged with said first and second bosses so as to connect said fixing member and said arm, said damping member configured to generate a first damping force, which is a resistance against the rotation of said arm, and a second damping force larger than said first damping force so as to damp vibration of said belt;
- said damping member further comprising at least one sleeve having at least one axially extending slit, said at least one sleeve provided between at least one of said first and second bosses and said first coil spring;
- wherein said first damping force acts upon said arm when said arm rotates in said first direction, and said second damping force acts upon said arm when said arm rotates in a second direction, which is the reverse direction to said first direction;
- and
- wherein when said arm rotates from said first rotation position in said second direction, said first coil spring and said sleeve act as a coil spring clutch that brakes the rotation of said arm due to a frictional sliding movement at least one of between said first coil spring and said sleeve and between said sleeve and one of said first and second bosses.
6 more elements
A tensioner comprising:
- a first engaging portion and a second engaging portion that are coaxially arranged with each other;
- an arm provided with a pulley that engages an endless belt, said arm rotating between a first rotation position and a second rotation position around said first and second engaging portions;
- a biasing member that urges said arm in a first direction from said second rotation position toward said first rotation position so as to tension a belt via said pulley;
- and
- a damping member that includes a first coil spring having two end portions engaged with said first and second engaging portions, said damping member configured to generate a first damping force, which is a resistance against the rotation of said arm, and a second damping force larger than said first damping force so as to damp vibration of said belt;
- said damping member further comprising at least one sleeve having at least one axially extending slit, said at least one sleeve provided between at least one of said first and second engaging portions and said first coil spring;
- wherein said first damping force acts upon said arm when said arm rotates in said first direction, and said second damping force acts upon said arm when said arm rotates in a second direction, which is the reverse direction to said first direction;
- and
- wherein when said arm rotates from said first rotation position in said second direction, said first coil spring and said sleeve act as a coil spring clutch that brakes the rotation of said arm due to a frictional sliding movement at least one of between said first coil spring and said sleeve and between said sleeve and one of said first and second engaging portions.
6 more elements
A tensioner comprising:
- a fixing member;
- an arm;
- a pulley rotatably provided on said arm such that said pulley engages an endless belt;
- a biasing member that urges said pulley into resilient contact with said belt;
- and
- a spring clutch that rotatably engages said arm to said fixing member, said spring clutch including a coil spring operating in conjunction with said biasing member and configured to generate a first tightening force and a second tightening force larger than said first tightening force, and at least one of a first engaging member and a second engaging member engaged with said coil spring to produce a first rotational resistance corresponding to said first tightening force and a second rotational resistance corresponding to said second tightening force;
- wherein
- said spring clutch further comprising at least one sleeve having at least one axially extending slit, said at least one sleeve provided between at least one of said first and second engaging members and said coil spring;
- said first rotational resistance occurs in a first rotational direction of said arm, and said second rotational resistance occurs in a second rotational direction opposite said first rotational direction, said first and second rotational resistances permitting rotation of said arm in both said first and second rotational directions;
- and
- wherein when said arm rotates from said first rotation position in said second direction, said coil spring and said sleeve act as a coil spring clutch that brakes the rotation of said arm due to a frictional sliding movement at least one of between said first coil spring and said sleeve and between said sleeve and one of said first and second engaging members.
8 more elements
A tensioner comprising:
- a pulley that resiliently contacts an endless belt;
- an arm that rotatably engages said pulley on a first rotational axis;
- a biasing member that urges said arm in a first direction so that said pulley tensions said belt;
- a fixing member that rotatably engages said arm on a second rotational axis parallel to said first rotational axis;
- and
- a spring clutch that rotatably connects said arm and said fixing member, said spring clutch operating in conjunction with said biasing member and configured to generate a first rotational resistance in said first direction and a second rotational resistance larger than said first rotational resistance in a second direction opposite said first direction while permitting rotation in both said first and second directions;
- said spring clutch member further comprising at least one sleeve having at least one axially extending slit, said at least one sleeve provided between at least one of said arm and said fixing member and a spring;
- and
- wherein when said arm rotates from said first rotation position in said second direction, said spring and said sleeve act as a spring clutch that brakes the rotation of said arm due to a frictional sliding movement at least one of between said spring and said sleeve and between said sleeve and one of said arm and said fixing member.
6 more elements
Dependencies are inferred from the claim text.