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.

A variable force tensioning assembly creates and maintains a tension force on an endless loop used to transmit power. The variable force tensioning assembly includes a body having a cylinder defining a cylinder inner diameter. An outer piston is disposed substantially within the cylinder and slidable therewithin. The outer piston includes an outer piston tube and a chamber divider extending through the outer piston tube. The outer piston and the body define a low rate portion. An inner piston is disposed at least partially within the outer piston tube and is slidable therewithin. The inner piston defines a high rate portion and acts with the outer piston against the body to create a variable force to push against the endless loop to maintain a constant tension in the endless loop.

A resister clip (35) includes engage portions (35a) engaging with an engage groove, a spring portion (35b) and operating portions (35c). The spring portion (35b) can be designed with a high degree of freedom in terms of a coil number of turns, a winding diameter and others and the engage portions (35a) are widened centering on the spring portion (35b), so that diameter-widening resistance can be optimized.

A tensioning device, more particularly a hydraulically actuated chain tensioner, for a chain drive of an internal combustion engine, having a tensioner housing, a tensioning piston which is displaceably guided in a piston bore of the tensioner housing and has a piston skirt, a transport securing means for fastening the tensioning piston in the tensioner housing, a adjustment apparatus for incrementally adjusting and limiting the working range of the tensioning piston, and a final position securing means for the captive arrangement of the tensioning piston in the piston bore. The transport securing means, the adjustment apparatus and the final position securing means together have a single securing ring for fastening the tensioning piston in the tensioner housing, the incremental adjustment and limiting of the working range of the tensioning piston and the captive arrangement of the tensioning piston. A chain drive, more particularly a control chain drive, of an internal combustion engine, having such a tensioning device is also provided.

A variable force tensioner (VFT) system that includes a primary piston split into two chambers disposed within a primary bore. The two chambers including a first low pressure chamber having a primary reservoir therein that feeds fluid through a check valve into a second high pressure chamber to control a biasing force on the primary piston. A piston bore clearance path can extend along a groove in the primary bore to feed oil back to the primary reservoir from the high pressure chamber.

A chain tensioner includes a sleeve fixedly disposed in a cylinder, with a first end of the sleeve inserted in a plunger and a second end of the sleeve protruding out of the plunger. A cylindrical space is defined between an outer periphery of the sleeve and an inner periphery of the cylinder. An oil supply passage opens to the cylindrical space. A communication passage is defined in the sleeve and provides communication between the cylindrical space and a reservoir chamber.

A hydraulic tensioning device for a chain drive, including tensioning piston, which is guided in a holder and which has locking grooves on the outer peripheral surface of the tensioning piston, and including a locking element, which has at least two annular sections and at least two radial extensions, wherein the locking element can be brought into engagement with one of the locking grooves by the at least two annular sections, and including a clamping stop and a sliding stop, which are axially spaced apart from each other. In order to simplify the design, the holder has at least two axial extensions, which extend in the axial direction between the clamping stop plane and the sliding stop plane. The at least two axial extensions and the tensioning piston do not enclose the at least two radial extensions.

To provide a simple-structured tensioner that generates less knocking noise at the start-up of the engine and that prevents an excessive chain tension, severe friction, noise or vibration during the running of the engine, while also reducing production costs. The tensioner includes a ring control mechanism that controls the position of a resilient ring. The ring control mechanism includes a front-side restricting part having a front-side restricting surface and capable of restricting forward movement of the resilient ring, and a rear-side restriction member having a rear-side restricting surface and capable of restricting rearward movement of the resilient ring. The front-side restricting part is fixed to or formed integrally with the housing. The rear-side restriction member is disposed movable in a front to back direction relative to the housing and the plunger.

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.

A hydraulic tensioning device for a chain drive, having a tensioning piston which is guided in a holder and which, on its outer circumferential surface, has locking grooves, an inner guide which projects into a cavity of the piston, and a locking element which has at least two annular sections and at least two radial extensions, wherein the locking element can be placed in engagement by the at least two annular sections with one of the locking grooves, and having a clamping stop and a sliding stop which are axially spaced apart from one another. To simplify the structural design, the holder has at least two axial extensions which extend in an axial direction between the clamping stop plane and the sliding stop plane, wherein the at least two axial extensions and the tensioning piston do not enclose the at least two radial extensions.