Ntn Corporation

Ntn Toyo Bearing Co., Ltd.

Kazuki Kawashima

Hisashi Hayakawa

Ken Yamamoto

Tomoyoshi Izutsu

Satoshi Kitano

Norio Yamazaki

Makoto Yasui

Tadahisa Tanaka

Isao Hori

Sadaji Katogi

Yoshikazu Hida

Tomoyoshi Egusa

Katsuhisa Suzuki

Tsuyoshi Niwa

Masayuki Imoto

An object of the present invention, in an idler pulley having a pulley main body formed of steel sheet, is to prevent the pulley main body and the outer ring of a bearing from creeping and the pulley main body from slipping off. An idler pulley according to the invention comprises a pulley main body adapted to have a belt entrained therearound, a ball bearing fitted in the pulley main body, and a shaft member fitted in the inner ring of the ball bearing, wherein a layer of a soft metal whose Young's modulus is lower than those of the pulley main body and the outer ring of the bearing is interposed between the inner surface of the pulley main body of steel sheet and the outer surface of the outer ring of the bearing. When a belt is entrained, this soft metal layer elastically deforms to thereby function to fill a clearance which develops between the pulley main body and the outer ring of the bearing, thereby minimizing the decrease of the joining force between the pulley main body and the outer ring of the bearing, thus preventing drawbacks, such as creep, from occurring.

Idler pulley

A chain tensioner keeps constant the tension of a chain for transmitting the rotation of an engine crankshaft to e.g. camshafts. It includes a housing having a cylinder chamber. A rod member has its rear end inserted in the cylinder chamber for pressing a chain. A tension adjusting spring biases the rod member outwardly of the housing. The chain tensioner further includes a hydraulic damper for damping a dynamic load applied to the rod member from the chain, and a thread engagement mechanism for preventing the rod member from retracting under a static load applied to the rod member.

Chain tensioner and chain system

An arrangement which can reduce the space between a tension pulley of an autotensioner and an engine block and thus reduce the installation space of an autotensioner. A sub-reservoir is provided at the side of a plunger of a hydraulic damper. The hydraulic damper is arranged between the tension pulley and the engine block so that it is received inside the outer periphery of the tension pulley with its plunger abutting a pin of an eccentric ring. It is thus possible to reduce the space between the tension pulley and the engine block.

Autotensioner

A hydraulic autotensioner is arranged so as to include a cylindrical body having a closed end, a plunger slidably mounted in the body and formed with a hole in a top surface thereof, and a rod having a bottom end which is inserted in the hole. The plunger partitions the interior of the cylindrical body into a pressure chamber and a reservoir chamber. The pressure chamber communicates with the reservoir chamber through a return passage. A pressure control spring biases the rod and the plunger in a direction out of the cylindrical body. The return passage is defined by an axial through hole extending through the bottom surface of the plunger. A groove is formed in the inner peripheral surface of the plunger or in a surface of a bottom portion of the rod.

Hydraulic autotensioner

A hydraulic autotensioner has a cylinder having a closed bottom end, a sleeve mounted in the cylinder and a plunger slidably mounted in the sleeve. The interior of the cylinder is divided into a reservoir chamber and a pressure chamber by the plunger which is formed with a passage through which the reservoir chamber and the pressure chamber communicate with each other. A check valve is provided in the passage to close the passage if the pressure of hydraulic oil in the pressure chamber increases above the pressure of hydraulic oil in the reservoir chamber. A return spring is mounted in the cylinder to bias a rod which is axially movable together with the plunger in such a direction as to protrude from an upper opening of the cylinder. The return spring is mounted in a space formed between the outer peripheral surface of the sleeve and the inner peripheral surface of the cylinder.

Compact hydraulic autotensioner with return spring mounted around a

A hydraulic autotensioner having a close-bottomed body in which is sealed hydraulic oil. A plunger is slidably mounted in the body with a gap formed therebetween through which the hydraulic oil can leak. The plunger is formed with a hole in the top thereof, and a return passage extending through the plunger from the bottom of the hole to the bottom of the plunger. A rod, having its bottom end inserted in the hole, is provided with a rod spring for biasing the rod in such a direction so as to protrude out of the body. A plunger spring is provided for urging the plunger against the bottom end of the rod. Also, a valve seat is provided on the bottom of the hole so as to be brought into close contact with the bottom end of the rod. The return passage is opened and closed by axial displacement of the rod relative to the valve seat.

A belt tension adjusting device having a fixed member, a support shaft extending vertically from the fixed member and a pulley arm having a boss formed with a boss. The support shaft is received in the bore to rotatably support the pulley arm. A damper mechanism is mounted between the support shaft and the boss for damping a pivoting motion of the pulley arm. A pulley is mounted on the pulley arm. A tension adjusting spring is coupled to the pulley arm for biasing the pulley to impart tension to a belt. A bearing is provided for receiving radial loads produced when the pulley arm pivots. Part of the bearing is located in part outside the boss.

Belt tension adjusting device

A belt tension adjusting device having a pulley arm having a bore formed with threads, a fixed member and a support shaft extending upwardly from the fixed member into the bore in the pulley arm. A bolt made of a synthetic resin is axially movably mounted on the support shaft and held in thread engagement with the threads formed on the bore. An elastic member is mounted in the bore between the bolt and the support shaft or a member integrally mounted on the support shaft for biasing the bolt in an axial direction. A coil spring is mounted on the pulley arm and having one end thereof in engagement with the pulley arm and the other end with the fixed member.

An autotensioner for controlling the tension of a belt. It is filled with a hydraulic oil containing poly-.alpha.-olefin as a basic ingredient. Since such an oil has excellent viscosity-temperature properties as well as good lubricating properties, a body and a piston slidably mounted in the body are abraded less at their sliding surface than with a prior art autotensioner and thus the size of an oil leakage gap formed therebetween is less subject to change. This will prevent cavitation in a pressure chamber formed in the body.

An autotensioner includes a cylinder having its bottom closed and filled with a hydraulic oil and air, an oil seal mounted in the cylinder to seal the hydraulic oil and air, a rod slidably extending through the oil seal, and a piston slidably mounted in the cylinder with its top end abutting the bottom of the rod. The interior of the cylinder is separated into an upper reservoir chamber and a lower pressure chamber by the piston. Both chambers communicate with each other through a channel formed in the piston. The rod is biased by a spring mounted in the reservoir chamber in such a direction as to protrude from the cylinder. A check valve is provided in the pressure chamber near the bottom of the piston to open the channel in the piston only when the pressure in the pressure chamber is lower than the pressure in the reservoir chamber. The cylinder may have an outer casing and an inner sleeve so that the piston can slide on the inner surface of the sleeve.

An autotensioner for adjusting the tension of a timing belt used with an automotive engine. It includes a cylinder case filled with a hydraulic oil, a piston partitioning the interior of the cylinder case into a pressure chamber and a reservoir chamber and a push rod having its bottom end coupled to the piston and the top end adapted to protrude from the cylinder case. A spring is provided to bias the piston and the push rod upwardly. The pressure chamber communicates with the reservoir chamber through a channel formed through the piston. A plate-shaped check valve is provided in the pressure chamber to open and close the bottom of the channel. The plate-shaped valve can respond quickly to the fluctuation of pressure in the pressure chamber because of its reduced mass. Thus, when the piston and the push rod rise biased by the spring, the valve can move quickly to such a position as to open the channel, thus allowing the hydraulic oil in the reservoir chamber to flow quickly and smoothly back into the pressure chamber. This will prevent cavitation in the pressure chamber. The responsiveness of the valve will be improved further by providing another spring for biassing the valve in such a direction as to open the channel.

Autotensioner for adjusting the tension of a timing belt

A belt autotensioner for giving a desired tension to a belt. It includes a tension pulley pressed against the belt, an eccentric shaft extending through the tension pulley to rotatably support it and formed with a hole arranged eccentrically from the axis of the tension pulley, an actuator having a cylinder and a push rod silidably mounted in the cylinder and having its one end protruding from the cylinder and butting a projection fixed to the eccentric shaft, a bolt extending through the hole in the eccentric shaft and the cylinder of the actuator to pivotally support the eccentric shaft and a spring for biasing the eccentric shaft to pivot it in such a direction as to increase the tension of the belt. The spring may be a torsion coil spring mounted around the eccentric shaft with its one end fixed to the outer periphery of the eccentric shaft and the other end fixed to the cylinder of the actuator.

Growing community of inventors

Iwata, Japan

Kazuki Kawashima