A tensioner device, includes a housing defining a cylindrical bore. A plunger is disposed in the bore and has a non-cylindrical outer surface. A spring is engaged with the plunger for biasing the plunger in an outward direction and an oil passage is in communication with the cylindrical bore for delivering pressurized oil to the bore. The non-cylindrical outer surface provides hydraulic clearance areas between the plunger and the bore to provide improved damping without high damping force.

An auto-tensioner includes: a base having a cylindrical part; an arm; a pulley around which a belt is to be wound; a friction member sandwiched between an inner circumferential surface of a cylindrical part and the arm; and a coil spring pressing the friction member against the arm in the axial direction and rotationally biasing the arm in one direction with respect to the base, in which the friction member includes: an arcuate surface, a first locking part, locked to the arm, and inclined with respect to the radial direction so as to face the one direction side as the first locking part goes toward an outside in the radial direction, and a second locking part, and the friction member and the arm include a restricting unit which restricts the friction member from moving toward the one direction side with respect to the arm.

To provide a simple-structured chain tensioner that reduces the burden of work required for assembling and maintenance, sufficiently damps the motion of the plunger, and helps reduce machining costs and size increases of the plunger and tensioner body. The chain tensioner includes a tensioner body with a plunger bore, a plunger, and a biasing member that biases the plunger. The plunger has raised portions with which a locking member engages. The plunger bore is provided with a locking member holding part on one side that is open. The locking member holding part is provided with an inclined surface at one end in the plunger entry direction, the inclined surface becoming progressively shallower in the plunger entry direction. The locking member can deform elastically in a cross section when engaging with the raised portion of the plunger.

The present invention relates to an auto-tensioner containing a base having a cylindrical part, a rotating member supported rotatably to the base, a pulley provided at the rotating member, a friction member sandwiched between the cylindrical part and the rotating member, and a coil spring locked to the friction member and the base and disposed in a state of being compressed in an axial direction, thereby biasing the rotating member in one direction, in which the friction member has an arcuate surface capable of sliding along the cylindrical part, a first locking part located further toward the one direction side than the arcuate surface in a circumferential direction of the cylindrical part and locked to the rotating member, and a second locking part locked to one end of the coil spring.

A tensioner device, includes a housing defining a cylindrical bore. A plunger is disposed in the bore and has a non-cylindrical outer surface. A spring is engaged with the plunger for biasing the plunger in an outward direction and an oil passage is in communication with the cylindrical bore for delivering pressurized oil to the bore. The non-cylindrical outer surface provides hydraulic clearance areas between the plunger and the bore to provide improved damping without high damping force.

A linear tensioner is provided for tensioning a traction mechanism provided in a drive system with a first adjustment element that has a hollow-cylindrical construction and a second adjustment element that is guided so that it can be moved longitudinally on this first element, wherein contact surfaces are formed on facing end surfaces of the adjustment elements, on which a compression spring actuating at least one of the adjustment elements in the tensioning direction is supported. A transport securing device is provided that prevents, in a specified locked position, a movement of the adjustment elements relative to each other by at least one locking element. For creating a linear tensioner, in which, due to the use of a transport securing device, the structural dimensions of the linear tensioner are not increased, the adjustment element is movable out of the locked position against the force of the compression spring into an unlocked position, in which the at least one locking element is automatically displaced into a receptacle of the one adjustment element, whereby the adjustment elements are permanently unlocked relative to each other.

A belt tensioner for a belt drive of a motor vehicle engine, comprising: a fixed part configured to be fixed with respect to the engine and provided with a pivot defining a rotation axis; an arm having a connection portion hinged to the pivot and rotatable about the rotation axis and an opposite portion rotatably supporting a pulley configured to cooperate with a belt of the drive; a main spring interposed between the fixed part and the arm to exert thrust on the arm such as to rotate said arm towards the belt; and at least one rolling bearing interposed between the arm and the pivot to support the arm and ensure the alignment thereof.

A filtering pulley has a hub configured to be fixed to a shaft for rotation thereabout, a crown mounted coaxial and rotationally free on the hub, and a plurality of elastic groups arranged circumferentially with respect to the hub and to the crown and interposed, each, between a pair of first elements integral with the hub and between a pair of second elements integral with the crown. The first elements have at least two spokes, carried by an actuator that is made of two portions that can be selectively coupled based on angular position data between the crown and the hub and/or based on data of torque transmitted between the different elements of the system comprising this pulley.

A tooth jump protection device is used to control chain slack and delay the torque at which chain jump occurs, thus increasing jump torque performance. The tooth jump protection device is preferably mounted to the transfer case.

To provide a buffer pad and a lever that can suppress noise and vibration that occur when a plunger cannot follow the lever swing. A buffer pad 2 is provided at a location on a base member 11 of a lever 1 where a plunger of a chain tensioner abuts against the base member, the buffer pad 2 having a thermoplastic molded body made of a thermoplastic elastomer in at least a part thereof.