A hydraulic tensioner (10) and method of manufacture can include a housing (12), a piston (16) moveable from a retracted position toward an extended position with respect to the housing (12) in response to fluid pressure, and a tensioner spring (36) biasing the piston (16) toward the extended position. The hydraulic tensioner (10) can include a modular sleeve (14) supported by the housing (12) and defining an aperture (15) for slidably receiving the piston (16) and defining an expandable fluid chamber (18). The housing (12) can provide a fluid passage (39) for fluid communication between the expandable fluid chamber (18) and a source of pressurized fluid. The housing (12) can have a seat (25) in fluid communication with the aperture (15). An end (38) of the modular sleeve (14) can be seated with respect to a seat (25) of the housing (12) to seal the fluid passage (39).

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 belt drive system for rotatably coupling an internal combustion engine to an electric machine is described. The belt drive system includes a serpentine belt and a hydraulic strut tensioner, wherein the hydraulic strut tensioner is disposed to exert a tension force on the serpentine belt. A controller is operatively connected to the electric machine and includes an instruction set that is executable to periodically induce a reduction in torque output of the electric machine.

A product for applying tension is disclosed. The product may include a block with a first bore opening into to the block. A body may be provided having a second bore substantially larger in diameter than the first bore. The body may be positioned against the block so that the first bore is open to the second bore. The body may have a passage for providing fluid to a pressure chamber from the second bore. The passage may be arranged to open to the second bore and form a tangent to the second bore. Fluid may flow from the first bore to the pressure chamber through the second bore and the passage substantially unimpeded. Fluid flow is impeded from the passage to the first bore as a result of the configuration of the first bore, second bore and passage.

A belt tensioner for an accessory drive of an internal combustion engine having a lever arm rotatably assembled to a hydraulic strut assembly. The hydraulic strut assembly including a fixing eye for rotatably mounting to a mounting boss of an engine, the fixing eye having a cupped portion at a first end to seat onto the mounting boss and a travel limiter at a second end extending along an axis of the hydraulic strut to limit travel of the lever arm toward the fixing eye.

An object of the present invention is to provide a tensioner that has a reduced number of components and lighter weight and is easy to assemble. The tensioner according to the present invention is configured such that a base member is detachably and mechanically joined to a rear end opening of a cylindrical plunger with a closed front end against the resilience of biasing means that is accommodated inside the plunger such as to be freely extend and contract. The joint between the plunger and the base member is a mechanical connection that is one of a thread engagement, a press-fit, and a pin connection.

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.

A tensioning device (1) for tensioning a traction mechanism of a traction mechanism drive, including a housing (2), a piston (3) that is mounted such that the piston can be displaced in an axial direction inside the housing (2), and a transport securing element (4), which in at least one transport position of the tensioning device (1) is arranged in the housing (2) transversely to the piston (3) and in abutment with the piston (3) such that a displacement of the piston (3) in at least one first axial direction is blocked. The transport securing element (4) is provided with a support portion (5), wherein in the transport position at least one first web area (6) of the support portion (5) is in abutment with one end face (7) of the piston (3), and an additional web area (8) of the support portion (5) extending in an axial direction away from the first web area (6) is supported in the housing (2), at least in a radial direction.

A base and movable platform are connected by a linearly extendable member, so that a motor may be adjustably located at a desired distance from other machinery which receives power. A motor mounted on such a movable platform may be linearly displaced so that belts, chain, or silent chain or the like may be adjusted to operate at a desired tension. In another embodiment, a motor driving a gear train may be adjusted so that the depth of engagement of meshed teeth and the allowable backlash between a driving gear on the motor and a driven gear may be adjusted and controlled. An automatic belt tension control system may be constructed by adding a tension sensor and a control module configured to maintain operating tensions within a preferred range and optionally to emit alarms or command a shutdown if an unsafe condition is detected.

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.