Tsubakimoto Chain Company

Masao Maruyama

Hitoshi Ohara

Makoto Kanehira

Takayuki Funamoto

Shigekazu Fukuda

Kazumasa Matsuno

Hiroshi Horie

Nobuyuki Fujimoto

Yoshihiro Kusunoki

Hiroki Ishida

Yoshinori Iwasaki

Masaru Morimoto

Masahiro Sato

Kenshi Suzuki

Nobuto Kozakura

Katsuya Nakakubo

Takero Nakagawa

Kazuo Kimura

Masaaki Matsumoto

Yutaka Uchiumi

Haruo Sugita

Koichi Kaihotsu

Nobuo Okamoto

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 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 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.

Silent chain

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 power transmitting mechanism includes a first silent chain trained around teeth of a first driving sprocket and a teeth of first driven sprocket, and a second silent chain trained around teeth of a second driving sprocket and teeth of a second driven sprocket. The first and second driving sprockets are mounted in parallel relationship on a single drive shaft, and the teeth of the first driving sprocket are offset from the teeth of the second driving sprocket by one-half pitch. The pitch of the driving sprockets is a random pitch which varies in a random pattern along the circumference of the sprockets. The silent chains have a single pitch. By thus phasing the two driving sprocket, periodic meshing impact sounds emitted from the respective silent chains are canceled out or offset each other. The periodicity of the meshing impact sound is agitated by the random tooth pitch of the driving sprockets to such an extent that resonance sound is sufficiently reduced.

Power transmitting mechanism with silent chain and sprockets

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 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.

A silent chain includes double rocker joint pins articulately connecting together adjacent links of the chain. The double rocker joint pins are each composed of a longer pin and a shorter pin. The longer pin has a cross-sectional shape different from that of the shorter pin, and the thickness of the longer pin as measured in a direction parallel to a chain pitch line is made greater than the corresponding thickness of the shorter pin. By thus designing the longer pin relative to the shorter pin, the longer pin has a large mechanical strength sufficient to withstand not only an impact force applied when the longer pin is swaged or riveted at opposite ends thereof, but also a shear force and a bending force applied at one time to opposite end portions of the longer pin during power-transmitting operation of the chain.

Link plates connected together by connecting members to form an endless silent chain each include a pair of teeth and a pair of connecting holes each receiving therein one of the connecting members. The teeth each have an outer flank, an arcuate tip end portion, and an inner flank. The outer flank has a rectilinear tooth face having an intermeshing point, and a tooth length extending from the intermeshing point toward a tip end of each tooth. The tooth length is 5 to 15% of a pitch between the connecting members. The tip end portion has a first arc adjacent to the outer flank and a second arc adjacent to the inner flank, the second arc having a smaller radius of curvature than the first arc. The shortest distance from a junction between the first and second arcs of the arcuate tip end portion to a face angle forming line of the outer flank is 0.5 to 3.0% of the pitch between the connecting members. With this construction, the silent chain can decrease a collision speed with respect to the tooth face of a sprocket at the time of intermeshing to thereby reduce noises, and provide a smooth and positive intermeshing with the sprocket.

A silent chain has a plurality of interconnected plates adapted for operative engagement with toothed surfaces of a sprocket. Each of the plates has flank surface portions and crotch surface portions, with the crotch surface portions having protruding portions. The protruding portions of the crotch surface portions make contact with the toothed surfaces of the sprocket at the beginning of engagement of each plate with the sprocket and are spaced away from the toothed surfaces of the sprocket at least during engagement of the flank surface portions with toothed surfaces of the sprocket.

Plate for a silent chain having a protruding portion for reducing the

A plate for a silent chain has a side punched into a forked shape for engagement with a sprocket. The forked side of the plate has inner engaging surfaces opposing each other, outer engaging surfaces, and an arcuate leg-side end surface connecting the inner engaging surfaces. The leg-side end surface, on which stress is likely to be concentrated, has a shear face tissue along at least 70% of the thickness of the plate. A silent chain having such a plate has a high plate fatigue strength and enhanced durability and reliability, and can be manufactured at a low cost.

Growing community of inventors

Osaka, Japan

Masao Maruyama