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 chain tensioner includes a sleeve fixedly disposed in the cylinder, with one end thereof inserted in the plunger and the other end protruding out of the plunger. A cylindrical space is formed between the outer periphery of the sleeve and the 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 the reservoir chamber.

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 sealed tensioner is used in an automotive application to keep a belt or chain under its intended tension as it wears and stretches. The sealed tensioner is hydraulic but lacks an outside oil supply. The sealed tensioner, in an example, includes an outer body having a first bore. A cartridge body is received in the first bore. The cartridge body has a second bore. A piston is carried in the second bore. A check valve is situated between a low pressure reservoir and a high pressure chamber. One or more baffle walls are located at the low pressure reservoir. The baffle wall(s) block an air pocket in the low pressure reservoir from entering the high pressure chamber.

A sealed tensioner is used in an automotive application to keep a belt or chain under its intended tension as it wears and stretches. The sealed tensioner is hydraulic but lacks an outside oil supply. The sealed tensioner, in an example, includes a body with a bore. A piston is carried in the bore. A clearance resides at a confrontation between the body and the piston. A check valve is situated between a low pressure reservoir and a high pressure chamber. The sealed tensioner further includes a closed cell foam that is situated at the low pressure reservoir.

The invention relates to a tensioner (100) comprising: a hollow body (10) provided with a bottom (12), said bottom comprising a central zone (120), a peripheral zone (121) raised relative to the central zone and an intermediate zone (122) an axis (30) two guide means (40, 50) for said axis two cups (60, 124), the cup (124) comprising a first portion (124A) in front of the peripheral zone and a second portion (124B) in front of the intermediate zone a spring (70) held between the cups and arranged around the second guide means so that there is a gap between the spring and the second guide means a valve (80) with a channel (90), the channel opening in front of the second portion of the cup (124) away from said second portion.

A hydraulic tensioner includes piston retaining, anti-return, and anti-rotation functions. A ratchet clip for the tensioner preferably has straight sides or legs substantially perpendicular to a connecting portion. The ratchet clip preferably is substantially rectangular or U-shaped. The ends of the ratchet clip opposite the connecting portion are preferably bent inwards after the ratchet clip has been assembled on the tensioner. The ratchet clip performs the piston retaining function, the anti-rotation function and the anti-return functions. It is unnecessary for the user to remove the ratchet clip after the tensioner is assembled on the engine.

This invention pertains to the field of hydraulic tensioners. A hydraulic tensioner of this invention includes a tensioner body having a bore in fluid communication with a source of pressurized fluid through an inlet, a hollow piston slidably received within the bore and having an outer diameter, a hydraulic pressure chamber defined by the hollow piston and the bore of the tensioner body, a piston spring received within the hydraulic pressure chamber for biasing the piston away from the inlet, and a metallic band surrounding the outer diameter of the piston. The metallic band forms a seal between an outer surface of the piston and the tensioner body when pressure builds in the hydraulic pressure chamber, wherein metallic bands or seals are placed over a hydraulic tensioner piston in order to seal the high pressure chamber and prevent or reduce leakage through the clearance between the piston and the tensioner body.

One or more radial holes in the body of the hydraulic tensioner are used to control outward hydraulic flow restriction from the hydraulic pressure chamber within the piston. The one or more holes can be arranged in different ways to allow the piston position to alter the outward oil flow of the tensioner.

A product for applying tension is disclosed. A block may have a first passage opening into the block. A body may have a first manifold and may be positioned against the block so that the first passage is open to the first manifold. The body may have a flow path for providing fluid from the first manifold to a second manifold and there through to a pressure chamber. The flow path may include a series of channels and may be configured to allow substantially unimpeded flow from the first manifold to the second manifold, and to impede flow from the second manifold to the first manifold. The flow path may be free of movable components.