Tsubakimoto Chain Company

Shigekazu Fukuda

Takayuki Funamoto

Hiroshi Horie

Kazumasa Matsuno

Masao Maruyama

Hitoshi Ohara

Makoto Kanehira

Yoshinori Iwasaki

Yoshihiro Kusunoki

Tadasu Suzuki

Kenshi Suzuki

Toyonaga Saito

Hiroshi Hashimoto

Tatsuya Konishi

Masatoshi Sonoda

Nobuto Kozakura

Katsuya Nakakubo

Toyonaga Saitoh

Kozo Inoue

Junya Kurohata

Sumio Watanabe

Nobuyuki Onoda

Hiroshi Hayafune

Masahiro Satoh

In a ratchet-type hydraulic tensioner for a chain transmission, having a plunger and a housing forming a high pressure oil chamber, an excess supply oil discharge passage is provided. The discharge passage communicates with an oil supply passage leading from an oil supply opening, which receives oil under pressure from a oil pump, to a hydraulic check valve mechanism in the housing, which delivers oil to the high pressure oil chamber. Excess oil is discharged to the exterior of the tensioner housing and directed toward the chain. Excessive chain tension is avoided, and smooth and reliable chain travel, and suppression of whistling sounds, are achieved.

Ratchet-type hydraulic tensioner

In a transmission comprising an endless silent chain and a sprocket the inside tooth faces of the link plates of the chain are identical to tooth profiles, arranged axially, of a hob cutter for forming teeth of the sprocket. The inside and outside tooth faces also satisfy Hi&equals;Ho&plus;Hs, where Hi is the distance from a pin center line Lp to a pitch line Li of the inside tooth faces, Ho is a distance from the pin center line to a pitch line Lo of the outside tooth faces, and Hs is the amplitude of polygonal motion of the chain. Each link plate also has a concave bottom surface between its teeth to avoid interference with edges of the involute teeth arising due to the chain polygonal motion amplitude when the outside tooth faces are brought into meshing engagement with the involute teeth and become seated thereon.

Silent chain power transmission apparatus

A silent chain includes guide link rows and joint link rows arranged alternately and articulately connected in an endless fashion by rocker joint pins each composed of a longer pin and a shorter pin. In each guide link row, the longer pin is fitted with two guide plates and also inserted through link plates disposed between the guide plates. In each joint link row, the shorter pin is inserted through link plates. The longer pin and the shorter pin are initially formed in a straight configuration and have the same cross-sectional shape. When the silent chain is stretched substantially straight after having been subjected to a proof load, the pitch of the guide plates is made slightly greater than the pitch of adjacent contact points between the longer pins and the shorter pins of the rocker joint pins in the guide link rows so that the longer pins are elastically deformed into a bow-like configuration bent toward the mating shorter pins. The rocker joint pins having the elastically deformed longer pins acquire spring or cushioning properties which are effective to improve the strength of the chain and reduce the operation noise of the silent chain.

Silent chain with rocker joint pins

A rocker joint silent chain includes rocker joints articulately connecting together multiple interleaved link plates and guide plates located outside the interleaved link plates in the widthwise direction of the chain. Each of the rocker joints is composed of a longer pin firmly fitted at opposite ends thereof in a pair of aligned pin-accommodation holes of two opposed guide plates, and a shorter pin having opposite ends projecting from opposite outer surfaces of the interleaved link plates. The ends of the shorter pin are in slight contact with inner surfaces of the guide plates. High-frequency noise and abrasive wear of the rocker joints and link plates, which may occur due to free movement of the shorter pin in the widthwise direction of the chain, can be avoided.

Rocker joint silent chain

Each link plate of a low noise silent chain has an inside meshing surface formed on the inside flank of each link tooth. The inside meshing surface includes a convexly arcuate mesh start portion disposed on a tip side of each link tooth, and a convexly arcuate mesh guide portion disposed on a root side of each link tooth. The arcuate mesh guide portion has a radius of curvature and a circular arc length which are greater than a radius of curvature and a circular arc length, respectively, of the convexly arcuate mesh start portion. When the silent chain engages a sprocket, the engagement proceeds smoothly and continuously from the inside meshing surface to the outside meshing surface. This contributes to the reduction of the noise level of the silent chain as a whole through suppression of meshing sound of the outside meshing surface and vibratory chain noise.

Low noise silent chain

A wear-resistant silent chain includes a large number of link plates articulately connected together in an endless fashion by rocker joint pins each composed of a long pin and a short pin. The long and short pins have an outer peripheral surface formed by, at least, a convexly arcuate rocker surface which is adjacent to the convexly arcuate rocker surface of another pin, a load-bearing surface on the side opposite to the rocker surface and being seated on an inner peripheral surface of each of a pair of pin holes formed in each link plate, and a pair of lubricant guide surfaces each extending substantially linearly from one circumferential end of the load-bearing surface to an adjacent circumferential end of the rocker surface while extending divergently with respect to the inner peripheral surface of each of said pin holes. The lubricant guide surface provides a large lubricant collecting area which is sufficient to lubricate the load-bearing surface with an enough amount of lubricating oil and thereby prevents local wear caused between the inner peripheral surface of each pin hole and the load-bearing surface of each pin.

Wear-resistant silent chain

A silent chain for use with a sprocket has a plurality of interleaved rows of link plates connected together in an endless fashion, each link plate having a pair of teeth. Each of the teeth has an inside flank and an outside flank surface merging at a tip of the tooth. The inside flank has a smooth contact surface which is smaller in width than the smooth contact surface of the outside flank surface. The point where the link plate starts to move into contact with the tooth flank of the sprocket is set to locate in an area having the smooth contact surface at a relatively high rate of occupancy. With this arrangement, noise occurring at the mesh between the link plate and the sprocket can be reduced. The point where the meshing engagement completes is set to locate in an area having the smooth contact surface at a relatively high rate of occupancy. This arrangement improves the wear resistance and fatigue strength of the link plate.

Silent chain

A silent chain include a number of link modules articulately connected together in an endless fashion by rocker joint pins. The rocker joint pins include a first rocker joint pin composed of a first longer pin and a first shorter pin each having a different first thickness in a direction of pitch of the rocker joint pins, and a second rocker joint composed of a second longer pin and a second shorter pin each having a different second thickness in the direction of pitch of the rocker joint pins. The second thickness of the second longer or shorter pin is different from the first thickness of a corresponding one of the first longer and shorter pins. The first joint rocker pin and the second rocker joint pin are arranged in a random pattern along the length of the silent chain so as to suppress generation of periodic noise when teeth of the silent chain and teeth of a sprocket engage with each other.

A silent chain power transmitting device includes a driving sprocket and at least one drive sprocket, and a silent chain stretched over the driving and driven sprockets to provide a tension run and a slack run on opposite sides of the driving sprocket. The driving and driven sprockets have a sprocket pitch (chordal pitch) designed to become substantially equal to a chain pitch of the tension run of the silent chain while operating under load. By thus designing the sprocket pitch relative to the chain pitch, toothed link plates of the silent chain are smoothly guided into sliding contact with teeth of the sprockets without causing objectionable interference or collision. The sprockets and silent chain are substantially free from abnormal wear and hence have an increased degree of durability.

Silent chain power transmitting device

A rocker pin for use in a power transmission chain has an identifying mark for distinguishing the rocker pin from another rocker pin having a different thickness or a different rocker surface. The identifying mark may include a groove, ridge, colored mark, lustrous streak or the like provided on a peripheral surface except a rocker surface in the longitudinal direction of the rocker pin. The rocker pin having such identifying mark can be visually identified with ease so that the rocker pin is prevented from being mixed with a different kind of rocker pins. This enables easy and confusion-free storage of the rocker pin and prevents incorrect combination of a longer pin and a shorter pin, which may occur when they are used in combination to form a single rocker joint.

Rocker pin and wire stock for producing the same

A chain includes a pair of rocker joint pins inserted through laterally aligned pin holes of two adjacent link plates. The pin holes have a pair of upper and lower pin-position constraining surfaces arranged to face upper and lower flat surfaces, respectively, of each rocker joint pin with a very small clearance defined therebetween so that the rocker joint pin is always kept in position against displacement in a vertical direction relative to the link plates. When the chain is urged to warp or bend into a V shape, each of the rocker joint pins is gripped by the upper pin-position constraining surface of one of the two adjacent link plates and a warp blocking surface of the other of the two adjacent link plate. Thus, such warping of the chain does not take place.

Chain with improved rocker pin joint structure

A guide plate a for silent chain is substantially arch-shaped and has a pair of pin holes formed therein at a position adjacent to opposite free ends of the arch-shaped guide plate. The arch-shaped guide plate further has an arcuate inner peripheral surface and an arcuate outer peripheral surface both extending arcuately about a center located at the midpoint of a pitch line segment interconnecting the pair of pin holes. The arcuate inner peripheral surface has a radius of curvature which is in the range of 35 to 45% of the chain pitch, and the arcuate outer peripheral surface is blended with the opposite free ends of the arch-shaped guide plate.

Guide plate for a silent chain

A silent chain includes guide links and articular links arranged in the longitudinal direction of the chain. The guide links each include one or more guide link plates, and the articular links each include two or more articular link plates. When the chain is in the straight-line state, the inside flank of each meshing tooth of any one of the link plates projects outwardly from the outside flank of each meshing tooth of another laterally adjacent one of the link plates. The projecting length of the inside flank relative to the outside flank is allowed to vary between the adjacent links, either in a random fashion or in a regular alternate fashion, along the length of the chain. By thus providing different projecting lengths of the chain's inside tooth flanks, the sliding engagement start time of sprocket teeth relative to the inside tooth flanks of the individual link plates is allowed to vary between the adjacent links, so that the periodic meshing sounds can be prevented from resonating to get louder, with the result that the overall noise level can be minimized.

Two rocker pins inserted into each of two pin holes of each link plate of a silent chain each include a rocker surface, a first non-contact surface opposed to an inner peripheral surface of the pin hole on a side opposite to the rocker surface, a pair of load-bearing surfaces contiguous with both circumferential ends of the first non-contact surface, and two second non-contact surfaces interconnecting the pair of load-bearing surfaces and both circumferential ends of the rocker surface, respectively. A part of the inner peripheral surface of the pin hole is formed in a pair of pin-seating surfaces which is in register with the pair of load-bearing surfaces of each rocker pin, respectively, to prevent rotation of the rocker pin within the pin hole. Since the load-bearing surfaces are supported by the pin-seating surfaces in an exactly matched or registered condition, rotation and wobbling of the rocker pin within the pin hole are securely prevented. Thus, the rocker pins and the link plates are substantially free from local wear which may often result in an excessive wear elongation of the silent chain.

A silent chain is constituted by a number of articulately connected link plates each having an engagement surface for meshing engagement with teeth of a sprocket. The link plates are press-formed so that the engagement surface includes a smooth sheared surface. All of the link plates have respective sheared surfaces along not more than 60% of the thickness of the link plates. In order to reduce noises produced when the link plates mesh with the sprocket teeth, more than 50% of the link plates have respective sheared surfaces along 7 to 15% of the thickness of the link plates and are arranged randomly in the silent chain.

Growing community of inventors

Osaka, Japan

Shigekazu Fukuda