Abstract: An object of the present invention is to provide a chain guide that can reduce vibration and noise while maintaining necessary strength, rigidity, and durability. The chain guide has a support wall extending forward from a boss part, which constitutes a circumferential wall of a pivot shaft, along a plane perpendicular to a pivot axis line. The support wall includes a base part that is provided with a running surface-side rib, and a connecting portion with a cross-sectional area thereof reducing toward the boss part. The running surface-side rib is not in contact with the boss part. The chain guide does not include a connecting portion that has a larger width than the thickness of the support wall and extends in a pivoting direction on a back side of the running surface-side rib in a region at a pivot shaft side end thereof.

Abstract: To provide a universal design chain guide that can provide a position, track, and length of contact between the chain guide and the chain for optimal performance even when used with different types of chains. The chain guide includes a guide surface slidably guiding a running chain and at least one mounting part. The guide surface includes a first guide surface extending along a longitudinal direction and a second guide surface parallel to and protruding more than the first guide surface. The second guide surface protrudes from the first guide surface with varying heights along the longitudinal direction.

Abstract: An object of the present invention is to provide a chain guide that can reduce vibration and noise while maintaining necessary strength, rigidity, and durability. The chain guide has a support wall extending forward from a boss part, which constitutes a circumferential wall of a pivot shaft, along a plane perpendicular to a pivot axis line. The support wall includes a base part that is provided with a running surface-side rib, and a connecting portion with a cross-sectional area thereof reducing toward the boss part. The running surface-side rib is not in contact with the boss part. The chain guide does not include a connecting portion that has a larger width than the thickness of the support wall and extends in a pivoting direction on a back side of the running surface-side rib in a region at a pivot shaft side end thereof.

Abstract: To provide a universal design chain guide that can provide a position, track, and length of contact between the chain guide and the chain for optimal performance even when used with different types of chains. The chain guide includes a guide surface slidably guiding a running chain and at least one mounting part. The guide surface includes a first guide surface extending along a longitudinal direction and a second guide surface parallel to and protruding more than the first guide surface. The second guide surface protrudes from the first guide surface with varying heights along the longitudinal direction.

Abstract: The hollow plunger of a hydraulic tensioner for an engine timing chain protrudes from a tensioner housing in an oblique downward direction. An inner sleeve fixed to the housing slidably protrudes into the interior of the plunger, and has a ball check valve at its protruding end. Oil is supplied though the sleeve and the check valve to a high pressure oil chamber formed inside the plunger, and flows outward through a two-part leakage path formed by a gap between the sleeve and the interior of the plunger and a gap between the exterior of the plunger and an interior wall of a plunger-accommodating hole in the housing. Any air that enters the tensioner accumulates in a region surrounding the upper end of the sleeve, rather than in the high oil pressure chamber inside the plunger.

Abstract: A tensioner unit comprises a tensioner body, a gasket in overlapping relationship to the tensioner body whereby the gasket can be sandwiched between the tensioner body and a mounting surface to which the tensioner body is to be secured, and a threaded mounting bolt inserted through a mounting hole in the tensioner body for securing the tensioner body to the mounting surface. A bolt hole is provided in the gasket, and the mounting bolt also extends through the bolt hole. The gasket grips the bolt and holds the mounting bolt, the gasket, and the tensioner body, in fixed relationship to one another, and maintains the gasket in a predetermined aligned relationship with the tensioner body when the gasket is in overlapping relationship with the tensioner body during mounting of the tensioner body on the mounting surface.

Abstract: In a hydraulic chain tensioner having a housing, a hollow plunger slidable in a plunger-accommodating hole in the housing, and a hollow sleeve extending into the plunger from a bottom of the plunger-accommodating hole, and a check valve mounted at the opposite end of the sleeve, a passage is provided on the outer surface of the sleeve to accelerate the balance of pressure between a first high pressure chamber between the check valve and the protruding end of the plunger and a second high pressure chamber between the inner end of the plunger and the bottom of the plunger-accommodating hole. In an alternative embodiment, balance is accelerated by communication between the second high pressure chamber and an oil reservoir inside the sleeve on the upstream side of the check valve.

Abstract: In the check valve of a hydraulic tensioner, a bell-shaped retainer is provided with plural, branched, leg portions which resiliently grip the outer surface of a ball seat. Oil induction slots are formed between adjacent branched leg portions of the retainer to provide oil flow paths that are unimpeded by the plunger-biasing spring of the tensioner.

Abstract: In a hydraulic tensioner having a relief valve inside its plunger, a relief valve spring-receiving plug, press-fit into the plunger is formed by forging a plurality of flat surfaces on its exterior. These flat surfaces, in cooperation with the cylindrical inner wall of the plunger, form plural oil passages, each having a segment-shaped cross-section. The oil passages allow flow of oil past the plug to a discharge opening at the front end of the plunger, and the flow of oil is substantially unaffected by circumferential displacement of the oil passages on the periphery of the plug relative to the oil passages on the periphery of the relief valve seat.

Abstract: In a hydraulic chain tensioner having a housing, a hollow plunger slidable in a plunger-accommodating hole in the housing, and a hollow sleeve extending into the plunger from a bottom of the plunger-accommodating hole, and a check valve mounted at the opposite end of the sleeve, a passage is provided on the outer surface of the sleeve to accelerate the balance of pressure between a first high pressure chamber between the check valve and the protruding end of the plunger and a second high pressure chamber between the inner end of the plunger and the bottom of the plunger-accommodating hole. In an alternative embodiment, balance is accelerated by communication between the second high pressure chamber and an oil reservoir inside the sleeve on the upstream side of the check valve.

Abstract: A check valve unit in a hydraulic tensioner comprises a check ball, a steel ball guide having an inner wall allowing a limited range of longitudinal movement of the ball but restricting its lateral movement, a steel retainer attached to the high pressure oil chamber side of the ball guide, and a steel ball seat attached to the oil supply side of the ball guide. Bulged portions formed on an outer surface of the ball guide are press-fit into the plunger-accommodating hole of the tensioner.

Abstract: The hollow plunger of a hydraulic tensioner for an engine timing chain protrudes from a tensioner housing in an oblique downward direction. An inner sleeve fixed to the housing slidably protrudes into the interior of the plunger, and has a ball check valve at its protruding end. Oil is supplied though the sleeve and the check valve to a high pressure oil chamber formed inside the plunger, and flows outward through a two-part leakage path formed by a gap between the sleeve and the interior of the plunger and a gap between the exterior of the plunger and an interior wall of a plunger-accommodating hole in the housing. Any air that enters the tensioner accumulates in a region surrounding the upper end of the sleeve, rather than in the high oil pressure chamber inside the plunger.

Abstract: In the check valve of a hydraulic tensioner, a bell-shaped retainer is provided with plural, branched, leg portions which resiliently grip the outer surface of a ball seat. Oil induction slots are formed between adjacent branched leg portions of the retainer to provide oil flow paths that are unimpeded by the plunger-biasing spring of the tensioner.

Abstract: In a hydraulic tensioner comprising a tensioner body and a hollow plunger slidable in a plunger-receiving hole, a deairing check ball assembly comprises a check ball, a ball seat, a ball retainer and a check ball biasing spring arranged to bias the check ball away from the seat and toward a high pressure chamber formed by a plunger-receiving hole and the interior of the plunger. The deairing check ball assembly can be incorporated into the tensioner body or into the plunger.

Abstract: A hydraulic tensioner comprises a hollow plunger slidable in a plunger-accommodating hole in a housing, the plunger and housing forming a high pressure oil chamber. A check valve unit, which includes a check ball and a check ball retainer, allows oil to flow into the oil chamber, but prevents reverse flow. A plunger-biasing spring, disposed inside the high-pressure chamber includes a close-wound portion fitting over the retainer of the check valve unit, and a portion having spaced windings, which extends and compresses axially with protruding and retracting movement of the plunger. The outer diameter of the close-wound portion is greater than the outer diameter of the portion having spaced windings.

Abstract: In a hydraulic tensioner having a relief valve inside its plunger, a relief valve spring-receiving plug, press-fit into the plunger is formed by forging a plurality of flat surfaces on its exterior. These flat surfaces, in cooperation with the cylindrical inner wall of the plunger, form plural oil passages, each having a segment-shaped cross-section. The oil passages allow flow of oil past the plug to a discharge opening at the front end of the plunger, and the flow of oil is substantially unaffected by circumferential displacement of the oil passages on the periphery of the plug relative to the oil passages on the periphery of the relief valve seat.

Abstract: A hydraulic tensioner comprises a hollow plunger slidable in a plunger-accommodating hole in a housing, the plunger and housing forming a high pressure oil chamber. A check valve unit, which includes a check ball and a check ball retainer, allows oil to flow into the oil chamber, but prevents reverse flow. A plunger-biasing spring, disposed inside the high-pressure chamber includes a close-wound portion fitting over the retainer of the check valve unit, and a portion having spaced windings, which extends and compresses axially with protruding and retracting movement of the plunger. The outer diameter of the close-wound portion is greater than the outer diameter of the portion having spaced windings.

Abstract: In a ratchet-type hydraulic tensioner for use with a timing chain of an internal combustion engine, two or more oil reservoirs gradually receive oil fed under pressure from an external source, and supply the oil through a hydraulic valve mechanism to a high pressure oil chamber formed by a plunger and a housing in which the plunger is slidable. Throttle holes, formed in partition walls separating the reservoirs, control the flow of oil from one reservoir to another. An excess oil discharge hole is optionally provided in one of the reservoirs. The invention prevents abnormal protrusion of the plunger, reduces chain noise and component damage due to wear, and rapidly re-establishes proper tension on engine start-up.

Abstract: In a hydraulic tensioner having a relief valve mechanism in which a spring-biased valve element is reciprocable in a bore, hitting sounds produced by collision of the relief valve element with a plug in the bore, and wear and breakage of the biasing spring, are prevented by providing an oil relief hole in a peripheral wall of the relief valve bore at a position where it is closed by the relief valve element when he relief valve element is moved by a rapid increase in oil pressure.

Abstract: The present invention relates to a hydraulic type plastic tensioner comprising a body of the tensioner, which is made of plastics, a hollow metallic cylinder fit into a circular hole formed in the body, a plunger and a check valve mechanism. A ball seat in the check valve mechanism is provided on a bottom portion of the circular hole, and a retainer in a retainer-integrated type cylinder is press-fit onto the check ball to hold the cylinder in the circular hole.