Tsubakimoto Chain Company

Hiroyuki Miyake

Hiroshi Hashimoto

Katsuya Nakakubo

Tsutomu Namie

Osamu Yoshida

Toru Fujiwara

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.

Downward angle settable hydraulic tensioner

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.

In a hydraulic tensioner, a deairing valve unit comprising a synthetic resin ball guide, a check ball a biasing spring, a ball seat, and a retaining disc, is press-fit into a hollow plunger, and disposed adjacent the protruding end of the plunger. The ball and seat of the deairing valve unit are arranged to block flow of oil out of the tensioner when the oil is under pressure, but open to allow air to flow out of the tensioner, through a vent in the protruding end of the plunger, after a negative pressure condition occurs inside the oil chamber of the tensioner.

Hydraulic tensioner

A low cost hydraulic tensioner of die-casting metal or synthetic resin with a separate metallic cylinder free from dropping out of the cylinder and fine surface finishing, is provided. The tensioner comprises a metallic cylinder fitted to a cylindrical hole formed in a body , a plunger energized by a spring and a pressure oil chamber formed between the inner part of plunger and the cylinder . The cylinder is provided with a bottom plate B having a through hole A allowing the inflow of oil. The bottom plate B is prevented from dropping out from the body by being engaged by the spring

A hydraulic tensioner which has a small number of components and hence can be reduced in size. The hydraulic tensioner includes a plunger 3 slidably fitted in a cylinder disposed in a tensioner body, a reservoir chamber formed in the tensioner body in a lower portion of the cylinder, a check valve permitting flow of an oil in a single direction from the reservoir chamber into the cylinder which is formed as a high pressure chamber, a low pressure chamber formed in the tensioner body exteriorly of the cylinder, an oil passage connecting a bottom of the low pressure chamber to a position between the check valve and the reservoir chamber, and a spring urging the plunger upwardly, wherein the low pressure chamber contains an air layer formed above a surface of the oil held in the lower pressure chamber. The oil passages and check valve enable the oil to flow into the high pressure chamber in a short time and hence efficiently dampen vibrations of the plunger.

A tensioner for a chain or toothed belt which includes an oil reservoir. Oil contained in the oil reservoir is hermetically sealed by a diaphragm fixed to the oil reservoir by a plug. A pressurizing means is mounted between the diaphragm and the plug. The pressurizing means includes a compression spring and a bowl-shaped spring seat. A diaphragm is urged by the pressurizing means. A detent portion, extending upwardly from the diaphragm, is integrally formed on the surface of the diaphragm facing the atmosphere. The spring seat includes a recess at the central portion of the spring seat so that the detent portion of the diaphragm is engaged with the recess preventing free movement between the diaphragm and the pressurizing means.

Growing community of inventors

Osaka, Japan

Hiroyuki Miyake