Two-armed tensioner for the drive belt of a motor vehicle
Described herein is a tensioner for a belt of a drive of a motor vehicle, comprising: at least two idle pulleys designed to co-operate with respective belt runs of the belt; two arms bearing the pulleys; and elastic means acting at least indirectly on the arms for tensioning the belt, in which the arms are constrained to one another, and at least one of the arms is hinged to a first mobile axis.
1. A tensioner for a belt of a drive of a motor vehicle, comprising:
a first and a second idle pulleys designed to co-operate with respective belt runs of said belt;
a first arm bearing said first idle pulley, said first arm being hinged about a mobile axis;
a second arm hinged to said first arm about the mobile axis and bearing said second pulley, said first and second arms being rotatable relative to each other about the mobile axis;
elastic means secured to a mobile element, the elastic means acting directly on one of said first and second arms and indirectly on the other of said first and second arms for tensioning said belt;
the mobile element being distinct from said first and second arm and mobile during operation, said mobile axis being substantially perpendicular to and carried by said mobile element, said mobile element changing positions in reaction to changes in tensioning action on the belt runs, said positions being determined by an equilibrium caused by said changes in tensioning action; and
arrest elements on said mobile element, said arrest elements co-operating with said arms for limiting opening of said arms with respect to one another.
2. The tensioner according to claim 1 , characterized in that said mobile element is hinged about a fixed axis.
3. The tensioner according to claim 1 , characterized in that said elastic means co-operate with one of said aims and with said mobile element.
4. A belt drive tensioner comprising:
first and second pulleys operating with a belt running over the pulleys;
a mobile element including a first end portion rotatable about a fixed axis at a hinge and a second end portion opposite to the first end portion;
a first arm rotatably coupled to said mobile element about a mobile axis, said first pulley being mounted on the first arm;
a second arm rotatably coupled to said first arm and to said mobile element about the mobile axis, said second pulley being mounted on the second arm;
elastic means secured to the mobile element, the elastic means acting directly on one of said first and second arms and indirectly on the other of said first and second arms to generate a tensioning force; and
arrest elements on said mobile element, said arrest elements co-operating with said arms for limiting opening of said arms with respect to one another;
said mobile element changing positions in reaction to changes in tensioning action on the belt, said positions being determined by an equilibrium caused by said changes in tensioning action.