A tensioner including a support member, a thrust member supported so as to be capable of reciprocating movement in a straight line along a first direction with respect to the support member, and a contact-type flat spiral spring. The flat spiral spring is disposed adjacent to the thrust member in a second direction orthogonal to the first direction. The flat spiral spring has a coil axis direction running in a third direction orthogonal to both the first direction and the second direction and includes an inner-end portion anchored to the support member and an outer-end portion anchored to the thrust member so as to bias the thrust member in a forward-direction and so as to be wound-up by movement of the thrust member in a retraction-direction.

A tensioner includes a movable section, a fixed section, a flat spiral spring, and a back-up spring. The movable section receives load from an entrained transmission body through a tension member. The fixed section supports the movable section so as to be capable of displacing. The flat spiral spring biases the movable section so as to resist the tension member. The flat spiral spring unwinds in a state in which there is a small inter-plate friction force in cases in which there is a large biasing force applied to the tension member to counter load acting from the tension member. The flat spiral spring winds-up in a state in which there is a large inter-plate friction force in cases in which there is a small biasing force applied to the tension member to counter load acting from the tension member. The back-up spring limits wind-up of the flat spiral spring.

A chain tensioning device is adapted to be coupled to a vehicle body and to be adjacent to a chain, and includes a connecting segment, a metallic resilient segment, a fixing member and a guiding member. The connecting segment includes a securing portion adapted to be coupled to the vehicle body and an extending portion adapted to be under the chain. The resilient segment is connected to the extending portion of the connecting segment via the fixing member, and has a spring constant which ranges from 0.01 to 1000 N/mm, and a Young's modulus which ranges from 69 to 220 megapascals. The guiding member is connected to the resilient segment and is biased by the resilient segment for maintaining a tension of the chain.

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.

A tensioner that includes a mount, a pair of tensioner arms, and a spring. The mount defines a movement axis. Each tensioner arm assembly has a first tensioner arm, which is coupled to the mount for sliding movement about the movement axis, a tensioner pulley and a spring guide. The tensioner pulley and the spring guide are coupled to an associated tensioner arm for movement therewith. The spring is mounted on the spring guides and biases the tensioner arm assemblies about the movement axis in respective directions that urge the tensioner pulleys toward one another.

A stack of disk springs are placed between a second piston of a dual hydraulic variable force tensioner system and a hydraulic tensioner arm to allow much higher spring rates if desired. The springs may be stacked in multiple configurations to provide different spring rates. Package space can be reduced depending on the number of springs and orientations of said springs within the tensioner arm.

Disclosed herein is an actuator. The actuator, in accordance with an aspect of the present disclosure, includes a motor configured to generate torque, a gear device configured to amplify the torque, a belt driving device configured to transfer the torque to the gear device, and a bracket unit configured to fix a distance between a rotation shaft of the motor and a gear shaft of the gear device, wherein the bracket unit includes a pair of support members configured to support a portion of an outer peripheral surface of a belt gear in the bracket driving device and prevent tooth disengagement of the belt gear.

A tensioning device for a traction drive comprises: a base member; at least one tensioning arm pivotably supported on the base member around a pivot axis, with a tensioning roller which is rotatably supported on a bearing carrier of the tensioning arm; spring means for resiliently loading the tensioning arm, wherein the spring means extend between a first spring support of the tensioning arm and a second spring support of the tensioning device over a circumferential length around the pivot axis; an adjusting mechanism for adjusting the first spring support relative to the bearing carrier of the tensioning roller in circumferential direction about the pivot axis. A method includes adjusting the torque of the tensioning device.

A tensioning arrangement for a traction drive comprises a base member; at least one tensioning arm, which is pivotably mounted relative to the base member about a pivot axis; a tensioning roller that is connected to a carrier element of the at least one tensioning arm by a bearing so as to be rotatable about an axis of rotation; and an adjustment mechanism configured to pivot the bearing relative to the carrier element within a pivot range and to fasten the bearing in a pivot position within the pivot range. A corresponding device can be provided for adjusting the tensioning arrangement.

A tensioner includes a power spring, and a backup member being in contact with the power spring and supporting the power spring by acting an urging force in a direction opposite to a radial shift of the power spring in a direction in which the power spring is wound. The power spring is unwound in a condition in which an inter-plate frictional force of the power spring is small in a case where an urging force acting from a power spring to a tension member is greater than a load acting from the tensioner arm to the power spring and the power spring is wound in a condition in which the inter-plate frictional force of the power spring is large in a case where the urging force acting from the power spring to the tension member is smaller than the load acting from the tension member to the power spring.