High-offset belt tensioners have a support base with a pivot tube and an arm coupled thereto rotation about a pivot axis. A flat wire torsion spring has an inner spring hook attached to the pivot tube and an outer spring hook attached to a first end of the arm at a position that counterbalances a hub load force. The torsion spring applies a spring force to the arm in a direction that moves with the arm throughout its entire sweep in a belt engaging direction. A first plane of the hub load force is axially offset from a second plane of the spring force, a fulcrum is defined between first and second ends of the arm, and a first lineal axial distance from the fulcrum to the first plane is greater than or equal to a second lineal axial distance from the fulcrum to the second plane.

In an aspect, a tensioner is provided for tensioning an endless drive member that is engaged with a rotary drive member on a shaft of a motive device. The tensioner includes a base that is mountable to the motive device, a ring that is rotatably supported by the base in surrounding relationship with the shaft of the motive device and which is rotatable about a ring axis, a tensioner arm pivotally mounted to the ring for pivotal movement about an arm pivot axis, and first and second tensioner pulleys. The first tensioner pulley is rotatably mounted to the tensioner arm. The tensioner arm is biased towards a first span of the endless drive member on one side of the rotary drive member. The second tensioner pulley is rotatably mounted at least indirectly to the ring and is biased towards a second span of the endless drive member on another side of the rotary drive member. The ring is rotatable in response to hub loads in the first and second tensioner pulleys that result from engagement with the first and second spans of the endless drive member.

A tensioning device for tensioning a traction mechanism of a belt drive comprises a base member; a first tensioning arm pivotably supported on the base member and carrying a first tensioning roller; a second tensioning arm pivotably supported on the base member and carrying a second tensioning roller; a spring arrangement with first and second springs arranged to be effective between the first and second tensioning arms; wherein the two tensioning arms, when being pivoted relative to each other within a first tensioning angle range, are force-loaded against each other by the first spring, wherein the second spring is force-free relative at least to one of the tensioning arms; and wherein the tensioning arms, when being pivoted relative to each other within a second tensioning angle range comprising larger tensioning angles than the first tensioning angle range, are force-loaded against each other by the first spring and the second spring.

In an aspect, a tensioner is provided for an endless drive member, and includes a shaft-and-base unit, a tensioner arm, a pulley, and a tensioner spring. The shaft-and-base unit is mountable to be stationary relative to an engine, and includes a fastener aperture for a fastener. The tensioner arm is pivotable relative to the shaft-and-base unit about a tensioner arm axis. The pulley is rotatably mounted to the tensioner arm for rotation and is engageable with an endless drive member. The tensioner spring is positioned to urge the tensioner arm in a first direction relative to the shaft-and-base unit. The tensioner spring includes a plurality of coils that are arranged generally helically about a longitudinal axis and are spaced radially from one another and generally increase in distance away from the axis in a longitudinal direction.

The present invention pertains to an auto tensioner (1) to be provided in an auxiliary-driving belt system, including a friction member (6) that is sandwiched between an arm (3) and an inner circumferential surface of an outer cylindrical portion (21) of a base (2) in the radial direction of the outer cylindrical portion (21) and that has an arc-shaped surface (60) locked to the arm (2) and slidable with respect to the inner circumferential surface of the outer cylindrical portion (21), in which the friction member (6) is provided so that the arc-shaped surface (60) remains at a height equal to or higher than a horizontal plane (HP) passing through a central axis (R) when sliding with respect to the inner circumferential surface of the outer cylindrical portion (21) as the arm (3) oscillates.

A tensioner comprising a base having a cylindrical portion extending axially, the cylindrical portion comprising a radially outer surface and a receiving portion that is radially inward of the radially outer surface, an eccentric arm pivotally engaged with the radially outer surface, a torsion spring disposed within the radially inward receiving portion, the torsion spring applying a biasing force to the eccentric arm, and a pulley journalled to the eccentric arm.

A tensioner comprising a base defining a hole, the hole having a center C, the hole having a diameter sufficient to receive a driven pulley, a rotary arm engaged with the base by a retaining member connected to the base, the rotary arm rotatable about the center C, a pivot arm mounted to the rotary arm on a pivot, the pivot offset from center C, a first pulley journalled to the rotary arm, a second pulley journalled to the pivot arm, a torsion spring engaged between the rotary arm and the pivot arm for biasing the second pulley toward the first pulley, a damping member frictionally engaged between the base and the rotary arm, and the rotary arm defining a portion for receiving a first pulley fastener whereby a first pulley position is adjustable.

A belt tensioning device comprises: a base member; a first tensioning arm, which is pivotably supported by a bearing sleeve on the base member around a first pivot axis and which comprises a first tensioning roller, wherein the bearing sleeve is configured radially elastically and is connected to one of the components, the base member and the first tensioning arm in a rotationally fixed manner, and which is rotatable relative to the other of the components, the base member and the tensioning arm a second tensioning arm, which is pivotably supported on the base member around a second pivot axis and comprises a second tensioning roller; a spring arrangement that pre-tensions the first tensioning arm and the second tensioning arm in circumferential direction relative to each other; pre-tensioning means, which that are arranged radially between a circumferential face of the bearing sleeve and a circumferential face of the component connected to the bearing sleeve to exert a radial force in direction relative to the component rotatable thereto.

An orbital tensioner comprising an annular base, a ring journalled to the annular base on a ball bearing, said ring having a ring axis of rotation (A-A), a first pulley journalled to the ring, a first pulley axis of rotation (B-B) offset from the ring axis of rotation (A-A), a pivot arm pivotally mounted to the ring, a pivot arm pivot axis (C-C) offset from the ring axis of rotation (A-A), a second pulley journalled to the pivot arm, a torsion spring biasing the pivot arm in a first direction, the ball bearing having a first race and a second race, the ring fixed to the first race, the annular base fixed to the second race, and a damping mechanism frictionally disposed between the ring and the base.

A tensioner comprising a base, a pivot arm pivotally engaged with the base, a pulley journalled to the pivot arm, a torsion spring engaged between the base and the pivot arm, the torsion spring comprising a planar cylindrical portion integrally formed into an end of the torsion spring, and a damping member engaged with the planar cylindrical portion, the damping member frictionally engaging the base and being loaded in an unwinding direction.