Abstract: A tensioner for a belt has a fixed part provided with a pivot defining an axis (A), an eccentric arm rotatably mounted on the pivot about the axis (A), a pulley rotatable about an axis (B) defined by the arm and configured to cooperate with a timing belt, a first spring-damper assembly interposed between the arm and the fixed part, and a second spring-damper assembly configured to act between the arm and the fixed part from a predetermined angle of rotation of the arm with respect to the fixed part.

Abstract: A tensioner for a belt has a fixed part provided with a pivot defining an axis (A), an eccentric arm rotatably mounted on the pivot about the axis (A), a pulley rotatable about an axis (B) defined by the arm and configured to cooperate with a timing belt, a first spring-damper assembly interposed between the arm and the fixed part, and a second spring-damper assembly configured to act between the arm and the fixed part from a predetermined angle of rotation of the arm with respect to the fixed part.

Abstract: A tensioner (1; 50; 60) for a vehicle belt drive, having a housing (2) defining a cavity (3) having an axis (A); at least one arm (4) fitted to the housing (2) to rotate about the axis (A); an idle pulley (5) fitted to the arm (4); a torsion bar elastic member (6) housed at least partly in the cavity (3) and having a first end portion (15) integral with the arm (4), and a second hand portion (16) connected rigidly to a retaining portion (17) to permit tensioning of the elastic member (6); and a damping device (30) for damping oscillation of the arm (4), and having a conical friction member (32) cooperating axially with a mating surface (34) and loaded by axial elastic means (33). The friction member (32) is interposed between the arm (4) and the housing (2); and the elastic member (6) produces an axial thrust component depending on torsion of the elastic member and for pressing the friction member (32) and the mating surface.

Abstract: A belt tensioner for a belt drive is designed to connect an engine shaft of an internal-combustion engine to a reversible electric machine which has the function of starting motor and current generator; the belt tensioner comprises a fixed part and a pair of arms, hinged on a common pin carried by the fixed part and provided with respective idle pulleys, and a spring, which forces the two arms towards one another so as to load the pulleys elastically against respective branches of the belt. The two arms of the belt tensioner are provided with respective first arrest elements, which are designed to interact with the fixed portion to define respective positions of arrest of the arms themselves under the action of the spring, and respective second arrest elements, which are designed to interact with the fixed portion to define respective positions of end-of-travel of the arms under the action of the pull of the belt.

Abstract: A tensioner (1; 50; 60) for a vehicle belt drive, having a housing (2) defining a cavity (3) having an axis (A); at least one arm (4) fitted to the housing (2) to rotate about the axis (A); an idle pulley (5) fitted to the arm (4); a torsion bar elastic member (6) housed at least partly in the cavity (3) and having a first end portion (15) integral with the arm (4), and a second hand portion (16) connected rigidly to a retaining portion (17) to permit tensioning of the elastic member (6); and a damping device (30) for damping oscillation of the arm (4), and having a conical friction member (32) cooperating axially with a mating surface (34) and loaded by axial elastic means (33). The friction member (32) is interposed between the arm (4) and the housing (2); and the elastic member (6) produces an axial thrust component depending on torsion of the elastic member and for pressing the friction member (32) and the mating surface.