Tsubakimoto Chain Company

Katsuya Nakakubo

Nobuto Kozakura

Tadasu Suzuki

Masao Maruyama

Toru Fujiwara

Hiroyuki Miyake

Norio Harada

Sumio Watanabe

Yuji Kurematsu

Shigekazu Fukuda

Nobuyuki Fujimoto

Kozo Inoue

Tsutomu Namie

Takeshi Ogawa

Yoshio Kurokawa

Naoki Wakabayashi

Nobuo Okamoto

There is provided a chain guide that reduces a space occupied by the chain guide in an engine room while maintaining required strength, rigidity, and durability with a simple configuration, reduces the number of manufacturing steps and the waste of a material, does not require a structure that permits an error, prevents increases in vibration and noise during use, and reduces the burden of a maintenance operation. The chain guide has a guide shoe and a base member that reinforces the guide shoe, and an attachment portion includes an attachment member that is provided separately from the guide shoe and the base member and can be fixed to at least one of the guide shoe and the base member or both of the guide shoe and the base member.

Chain guide

A tensioner has a tensioner body and a plunger slidably mounted in a hollow cylindrical part of the tensioner body. A plug is screwed into a female or internal screw formed from one end of the hollow cylindrical part. A coil spring is loaded in a spring accommodating hole of the plunger and in a spring accommodating hole of the plug. The coil spring is a left hand spring. On the other hand, the direction of the plug being screwed into the tensioner body is right, which is opposite to the winding direction of the coil spring. Since the direction of the plug being screwed and the winding direction of the coil spring are different, when the plug is being screwed into the tensioner body with the coil spring held between the plug and the plunger, the coil spring slides on the bottom of the spring accommodating hole of the plunger or on the bottom of the spring accommodating hole of the plug without being caught at either end. Thus, the tensioner can be assembled very smoothly without producing powders by abrasion which may hinder smooth sliding movement of the plunger.

Tensioner

A plunger equipped with a relief valve mechanism is slidably mounted in a tensioner housing. The relief valve mechanism has a valve spring disposed between a valve and a spring retainer plug in a compressed condition. The spring retainer plug has a stopper surface formed on the side which opposes the valve. The maximum displacement of the valve and the maximum amount of compression of the valve spring are defined by the stopper surface so that the maximum shear stress acting in a wire of the valve spring is less than a fatigue limit of the valve spring wire.

Tensioner with relief valve mechanism

A closed hydraulic tensioner has a high-pressure chamber, a low-pressure chamber and a reservoir that are previously filled with an oil sealed in the hydraulic tensioner. The hydraulic tensioner further has a pressure chamber disposed next to said reservoir with a movable member disposed therebetween so as to displace the movable member toward the reservoir to thereby pressurize the oil inside the reservoir. The pressure chamber is supplied with an oil from the exterior of the tensioner.

Closed hydraulic tensioner

A tensioner has a substantially U-shaped stopper pin hooked at opposite end parts on a tensioner body and part of a plunger, respectively, to keep the plunger in a retracted position against the force of a spring before the tensioner is mounted to an engine body at an appropriate position relative to a power transmitting chain.

Tensioner with plunger stopper pin

A tensioner device for adjusting a tension in a chain wound around two sprockets includes a tensioner lever held in sliding contact with a slack run of the chain, an oil-filled tensioner provided on a stationary member, and a ratchet tensioner provided on the tensioner lever. The oil-filled tensioner includes a piston movable back and forth relatively to a housing attached to the stationary member, and a spring urging the piston in the forward direction. The ratchet tensioner includes a plunger movable in the forward direction relative to a housing formed integrally with the tensioner lever, and a spring urging the plunger in the forward direction. The piston and the plunger are held in face-to-face abutment with each other. The spring of the oil-filled tensioner has a larger spring coefficient than the spring of the ratchet tensioner. With this construction, when a sag of the chain is in excess of the forward stroke of the piston of the oil-filled tensioner, the plunger of the ratchet tensioner moves forward to cover a shortage of forward stroke of the piston. The tensioner device can continue proper tension-adjusting operation over a long period of use of a chain drive mechanism in which it is incorporated.

Tensioner device for chain drive mechanism

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.

Hydraulic tensioner

A hydraulic tensioner 10 includes a piston rod 12 slidably fitted in a cylinder 14 with a small gap or clearance therebetween, and a housing 16 containing the cylinder 14. A ball seat 20 is press-fitted in an end of the cylinder 14 opposite to the piston rod 12 so as to define within the cylinder 14 a high pressure oil chamber 21. The housing 16 has a partition wall 26 at a substantially central portion thereof. The cylinder 14 is loosely fitted in the housing 16 with its longitudinal portion extending forwardly from the partition wall 26. The partition wall 26 has an oil passage 32 having an inside diameter smaller than the outside diameter of the ball seat 20, so that the cylinder 14 and the ball seat 20 are in abutment with the partition wall 26 of the housing 16. A force tending to retract the piston rod 12 generates a pressure which acts on the partition wall 26 either directly via a spring 24 and the cylinder 14 or via the high pressure oil chamber 21 and the ball seat 20.

A hydraulic tensioner 10 includes a hollow housing 14 having formed therewith an intermediate partition wall 12, a circular hollow cylinder 16 disposed concentrically in the housing 14, and a piston rod 18 slidably received in the cylinder 16 with a small gap or clearance therebetween. The cylinder 16 and the piston rod 18 jointly define therebetween a high pressure oil chamber 20. The pressure in the high pressure oil chamber 20 counteracts the force tending to retract the piston rod 18. The piston rod 18 projects from an open end of the housing 14, and a seal 24 surrounds the piston rod 18 to seal or close the end of the housing 14. The piston rod 18 has secured thereto a rod guide 28 disposed within the low pressure oil chamber 26. A spring 36 is disposed in a compressed condition between the housing 14 and the rod guide 28 to urge the piston rod 18 in the advancing direction. The rod guide 28 has radially elongated oil holes or passages 38 formed in its surface which engages the spring 36. The oil passages 38 extend radially outwardly from an inner peripheral surface of the rod guide 28 press fitted with the piston rod 18 and also extends axially through the rod guide 28, and are positioned so that they are not closed by the end of the spring.

A tensioner includes a plunger slidably inserted in a housing and biased by spring means. The spring means include sequentially operable first and second portions in which the first portion has a relatively larger pitch and large spring modulus and the second portion has a relatively small pitch and small spring modulus. When the spring means is depressed a certain degree, the coils of the second spring portion 16 will move into close contact with each other to vary the spring modulus. Thus, the amount of backward movement and jutting out speed of the plunger will be decreased, thereby a required tensile force will be given to a belt, or the like, without delay.

Tensioner with spring having nonlinear characteristics

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.

Preventive structure for preventing extraordinary deformation of a

In a fluid tensioner of the piston and cylinder type an annular element is provided either on the piston or on the wall of the cylinder. In the case of an annular element on the wall of the piston, the annular element has a coefficient of linear expansion greater than that of the wall of the cylinder. In the case of an annular element on the wall of the cylinder, the annular element has a coefficient of linear expansion less than that of the piston material. In both cases, the annular element provides compensation for changes in hydraulic fluid viscosity to maintain a constant leak-down rate, allows for flexibility in the choice of piston, rod and cylinder materials.

Temperature compensated tensioner

A hydraulic fluid tensioner for a toothed belt, having a piston with a piston-carried ball and seat check valve, utilizes a ball pressing spring having a spring force more than 30 times the weight of the ball and less than 60% of force resulting from the hydraulic pressure acting on the ball and urging the check valve open as the piston moves in the projecting direction. The spring force prevents rapid accelerating movement of the piston, or vibrations of the tensioner, from causing irregular piston movements resulting in noise and vibration.

Tensioner for a toothed belt

In a hydraulic tensioner, shock absorber or lash adjuster having a plunger in a cylinder filled with hydraulic fluid, and having a coiled compression spring acting on the plunger in a pressure chamber on one side of the plunger, air scavenging through the restricted space between the plunger and the cylinder wall is improved by providing radial grooves either on a face of the plunger contacted by the spring, or on the spring-contacting face of a plug which is located between the spring and the plunger. The radial grooves enable air to escape from the interior of the coil spring and move toward the cylinder wall. The grooves increase in depth proceeding from the interior of the spring toward the exterior thereof.

Hydraulic pressure apparatus with air scavenging

In a fluid tensioner for a camshaft drive belt, a piston rod is sealed by a flexible diaphragm having an enlarged inner end clamped in a conforming groove in the piston rod by a spring clamp. This maintains the inner end of the diaphragm at a fixed position on the piston rod, and provides a labyrinthine seal preventing leakage of fluid. A flattened portion of the piston rod fits a D-shaped opening in a cap to prevent rotation of the piston rod and premature failure of the seal. A dust seal located on the cap also has a D-shaped hole, aligned with the D-shaped hole in the cap, and conforming to the flattened part of the piston rod.

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Osaka, Japan

Katsuya Nakakubo