A hydraulic auto-tensioner includes a cylinder with a sleeve fitting hole, and a sleeve press-fitted therein. A rod has its bottom end slidable in the sleeve. A return spring is mounted between a spring seat at an upper portion of the rod and a bottom surface of the cylinder. An oil passage, with a check valve, is formed between the fitting surfaces of the sleeve fitting hole and the sleeve and communicates the pressure chamber with the reservoir chamber. The rod has a valve fitting hole open to its bottom surface, and an oil passage communicating the valve fitting hole with the reservoir chamber. A relief valve, mounted in the valve fitting hole, includes a valve seat with a valve hole having an orifice for restricting the flow rate of oil released from the pressure chamber into the reservoir chamber through the oil passage when the relief valve opens.

Systems and methods are provided for determining the length of a traction mechanism that is part of a traction drive of an engine. In one example, a method includes determining a position of a movable tensioning device relative to a traction mechanism drive using measuring technology, determining an actual length L.sub.AS of a traction mechanism computationally using the position of the tensioning device, determining a length change L with respect to a predefinable setpoint length L.sub.AS computationally using the computationally determined actual length L.sub.AS, and adjusting one or more operating parameters based on the length change.

A segmented pulley defining an outer peripheral surface for engaging an endless member of a segmented pulley transmission is provided. The segmented pulley comprises: a plurality of pulley segments configured to be sequentially movable between an engaged region and a disengaged region to transition the endless member between the segmented pulley and a concentric pulley in the segmented pulley transmission, each of the pulley segments having a body defining a portion of the outer peripheral surface. The plurality of pulley segments includes a transition segment having an integrated support extending from the body of the transition segment, the integrated support being configured to support the endless member when transitioning the endless member between the segmented pulley and the adjacent pulley in the segmented pulley transmission. A segmented pulley transmission comprising the segmented pulley is further provided.

A tensioner device for a belt or chain defines a housing defining a bore with a plunger disposed in the bore. A spring is engaged with the plunger for biasing the plunger in an outward direction. The housing further includes an oil chamber connected to an oil passage in communication with the oil chamber for delivering pressurized oil to the oil chamber, wherein when the oil chamber is pressurized the pressurized oil applies a counter force opposing a force of the spring.

Provided is a chain tensioner that is capable of restricting the movement of a plunger at an engagement position, hardly causes its breakage and abrasion even if receiving a great force applied to the plunger, needs no setting for a backlash amount, and allows the engagement position of the plunger to be freely shifted forward and backward. The tensioner body has an engagement member that extends toward and retracts from engagement grooves provided on the outer periphery of the plunger, a press member that presses, in one direction, a cam member which maintains and releases the extending state of the engagement member, and a hydraulic supply path through which oil is supplied to press the cam member in a direction opposite to the pressing direction of the press member.

A belt drive arrangement for an internal combustion engine, includes a drive pulley which is driven by a crankshaft of the internal combustion engine, a first output pulley with which a first auxiliary unit can be driven, a second output pulley with which a second auxiliary unit can be driven, and a belt which has an inner face and an outer face opposite the inner face and which loops at least some portions of the drive pulley and the output pulleys as a belt transmission. The inner face of the belt loops the drive pulley and the first output pulley while physically contacting same, and the outer face loops the second output pulley while physically contacting same. An internal combustion engine is provided with such a belt drive arrangement.

A hydraulic auto-tensioner includes a plunger fitted to a bottom end portion of a rod so as to be slidable along a radially inner surface of a valve sleeve and a radially outer surface of the rod. The plunger has a bottom plate formed with a valve hole. A first leakage gap is defined between sliding surfaces of the plunger and the valve sleeve, and a second leakage gap of which the flow resistance is lower is defined between sliding surfaces of the plunger and the rod such that while the engine is running normally, oil in a pressure chamber leaks into a reservoir chamber through the second leakage gap, and when starting the engine by actuating a starter/generator, the plunger rises until the valve hole is closed so that oil in the pressure chamber leaks into the reservoir chamber through the first leakage gap.

A multi-axis tool for pre-tensioning a camshaft-drive element tensioner in an engine includes a housing having first and second faces and a length. The housing defines a first passage arranged along a first axis and a second passage arranged along a second axis. The second axis is parallel to the first axis and each passage extends through the length of the housing. The tool also includes a first lug arranged on and extending beyond the first face. The first passage extends through the first lug. The tool also includes a second lug extending beyond the second face and arranged along a third axis that is parallel to the first axis. An indicator rod is arranged partially within the second passage and configured to selectively extend beyond the first face. An elastic element is arranged inside the second passage and configured to extend the indicator rod beyond the first face.

The present disclosure describes a variable belt tensioner of an internal combustion engine for adjusting a belt tensioning. The tensioner includes in a series configuration an electric motor, a worm drive, a lever drive and a belt tensioner roller. The worm drive is driven by the electric motor and is mechanically connected to the lever drive for transmitting a rotation thereto. The lever drive is mechanically connected to the belt tensioner roller for transmitting a translation thereto, thus allowing the belt tensioner roller to adjust the belt tensioning.

Provided is a tensioner in which the durability of the tensioner body is increased, the tensioner body is reduced in weight, and the arrangement space is reduced. A tensioner 100 includes a tensioner body 110, a plunger 120, and a ratchet 130. The tensioner body 110 has a hole outer circumferential wall 112 and a pair of pin support walls 116, 117. The hole outer circumferential wall 112 has a pair of outer circumferential wall portions 113, 114 crossing a virtual line L extending in the pin longitudinal direction through the center of the plunger housing hole 111. At least one of the outer side surfaces of the pair of pin support walls 116, 117 is formed on the inner side, in the pin longitudinal direction, of the outer side surface of one of the outer circumferential wall portions 113, 114.