Ntn Corporation

Tadahisa Tanaka

Seiji Sato

Satoshi Kitano

Takehiro Takano

Aisaku Satomura

Hisashi Hayakawa

Kazuki Kawashima

Eiji Maeno

Masaki Kawachi

Tasuku Furukawa

Toshikatsu Miyaji

Yoshio Kato

Naoto Honda

A fixing tool of an auto-tensioner includes inwardly inclined engaging pieces inclined inwardly so as to be opposed to respective tapered surfaces of a spring seat and a cylinder of the auto-tensioner. The engaging pieces have concave surfaces that contact the tapered surfaces over a circumferentially extending area. This minimizes the deformation of the engaging pieces such that the diametrical distances therebetween increase due to contact with the tapered surfaces when sandwiching the spring seat and the cylinder with the engaging pieces from the axially opposite directions, thereby preventing the fixing tool from coming off.

Auto-tensioner

A hydraulic auto-tensioner includes a sleeve having its bottom end press-fitted in a sleeve fitting hole in the bottom surface of a cylinder, a rod having its bottom end slidably fitted in the sleeve, and a return spring mounted between a spring support at the upper portion of the rod and the bottom surface of the cylinder. A pressure chamber communicates with a reservoir chamber through a passage formed between fitting surfaces of the sleeve fitting hole and the sleeve. The passage has a check valve. The rod has a valve fitting hole and a communication passage through which the valve fitting hole communicates with the reservoir chamber. The valve fitting hole has a relief valve. An orifice is formed between a valve hole formed in a valve seat of the relief valve and a valve body to prevent a sharp drop in pressure in the pressure chamber.

Hydraulic auto-tensioner

A hydraulic auto-tensioner includes a cylinder with a sleeve fitting hole, and a sleeve press-fitted therein. A rod has its bottom end slidable in the sleeve. A return spring is mounted between a spring seat at an upper portion of the rod and a bottom surface of the cylinder. An oil passage, with a check valve, is formed between the fitting surfaces of the sleeve fitting hole and the sleeve and communicates the pressure chamber with the reservoir chamber. The rod has a valve fitting hole open to its bottom surface, and an oil passage communicating the valve fitting hole with the reservoir chamber. A relief valve, mounted in the valve fitting hole, includes a valve seat with a valve hole having an orifice for restricting the flow rate of oil released from the pressure chamber into the reservoir chamber through the oil passage when the relief valve opens.

A hydraulic auto-tensioner includes a plunger fitted to a bottom end portion of a rod so as to be slidable along a radially inner surface of a valve sleeve and a radially outer surface of the rod. The plunger has a bottom plate formed with a valve hole. A first leakage gap is defined between sliding surfaces of the plunger and the valve sleeve, and a second leakage gap of which the flow resistance is lower is defined between sliding surfaces of the plunger and the rod such that while the engine is running normally, oil in a pressure chamber leaks into a reservoir chamber through the second leakage gap, and when starting the engine by actuating a starter/generator, the plunger rises until the valve hole is closed so that oil in the pressure chamber leaks into the reservoir chamber through the first leakage gap.

In a fulcrum bearing device for a pulley arm, a sleeve is inserted in a shaft hole formed in a boss portion of a pulley arm, washers are fitted on the outer peripheries of small diameter tube portions formed at the respective end portions of the sleeve, and the sleeve is fixed to an engine block by means of a bolt inserted through the sleeve and tightened, so that the pulley arm is pivotally supported. The shaft hole is formed at its respective end portions with seal receiving recesses having large diameters. Each seal member includes a cylindrical portion provided on its outer peripheral portion and press-fitted in the seal receiving recess, and a radial lip extending obliquely inwardly and provided on the inner periphery of the seal member. The distal end portions of the radial lips are kept in elastic contact with the outer diameter surface of the sleeve.

Fulcrum bearing device for pulley arm

A hydraulic auto-tensioner includes a cylinder containing hydraulic oil, a rod inserted in the cylinder, and two coupling pieces mounted to the bottom of the cylinder and the top end of the rod, respectively. A support ring is inserted in the mounting hole of each coupling piece, and a bush is inserted in the support ring. One of the radially inner surface of the mounting hole and the radially outer surface of the support ring is a curved surface such that the support ring is alignable. Radially outwardly extending flanges are formed at one end of the support ring and at the other end of the bush such that the flanges axially face the respective end surfaces of the coupling piece with gaps left therebetween. A coupling arrangement is provided between the support ring and the bush which is adapted to engage both the support ring and the bush when the bush is inserted into the support ring, thereby axially inseparably coupling them together.

In a tension adjusting device for an engine accessory driving belt by tightening a boltthreaded into an engine block, a fulcrum shaftis fixed. A tension pulleyis rotatably supported by a pulley armpivotally supported about the fulcrum shaft. A regulating force of a hydraulic auto-tensioner is applied to the pulley armto press the tension pulley against the belt B. A washeris disposed between a bossformed on the pulley armand the headof the bolt. The washerhas an outer cylindrical portioncovering one end of the boss. A slingeris mounted on the end of the bossto define a labyrinthbetween the slingerand the cylindrical portion, thereby preventing entry of muddy water and dust into the bearing portion pivotally supporting the pulley arm

Tension adjusting device for engine accessory driving belt

In a swash plate type compressor comprising a piston slidably received in a cylinder bore disposed parallel with the driving shaft and a swash plate obliquely attached to the driving shaft and engaged by the piston through a bearing device, the bearing device comprises a spherical seat composed of a single concave surface formed in the piston , and a substantially hemispherical shoe contacting the spherical seat , the outer peripheral surface of the shoe being composed of a skirt portion , a top portion having a larger radius of curvature, R , than that R of the spherical seat , and a transition portion contacting the spherical seat between the skirt portion and the top portion and having a smaller radius of curvature, R , than that R of the spherical seat

Bearing device for swash plate type compressors

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

Contact between the top portion and the spherical seat of the piston is avoided through a simple arrangement and even if the swash plate angle is increased, a suitable contact portion is obtained. To this end, the top portion of a shoe for swash plate type compressors is composed of a partial spherical surface having a larger radius of curvature than that of the outer peripheral surface which contacts a seat surface formed in the piston, the top portion being smoothly continuous with the outer peripheral surface. Further, the generatrix of the outer peripheral surface of the shoe in contact with the seat surface is an arc whose center of curvature is radially spaced from the centerline of the shoe and whose radius of curvature is shorter than that of the seat surface, whereby the outer peripheral surface of the shoe contacts the seat surface of the piston at a predetermined position; this makes it easier to control the contact of the shoe for swash plate type compressors.

Growing community of inventors

Shizuoka, Japan

Tadahisa Tanaka