Borg-Warner Automotive, K.k.

Borgwarner Morse Tec Japan K.k.

Tetsuji Kotera

Tomonori Okuda

Kouji Morishige

Hiroyuki Takeda

A link plate for silent chains includes a pair of teeth, each formed of an inside flank and an outside flank and a pair of pin apertures. A moment of force around a pin M=F&#xd7;Lo, where F is a force applied by a sprocket tooth against the outside flank, and Lo is a length of a perpendicular drawn from a center O of a pin aperture to an action line of the force, is decreased by decreasing Lo. The link plate engages a sprocket tooth on an intersection between a straight line n and a flank, line n and the direction of a central line connecting each O forming a pressure angle &#x3b1;, and contacting a circle having a center O and a radius r&#x3c;0.25&#xd7;P, where P is a pin aperture pitch. Also, &#x3b1; of the outside flank satisfies an inequality, 32&#xb0;&#x2266;&#x3b1;&#x3c;34&#xb0;, to lessen the force.

Link plate for a silent chain

In a silent chain, multiple link plates are interleaved and connected to each other by connecting pins in a rocker joint. The rocker joint includes a joint pin and a rocker pin which are inserted into pin apertures. Guide links are placed on both ends of the joint pins. The joint pins are slightly longer than the rocker pins. Each rocker pin and joint pin has a cross-sectional area. The cross-sectional area of the joint pin is made larger than that of the rocker pin. In another embodiment, the rocker joint has a joint pin with a greater thickness than that of the rocker pin. Another embodiment of the invention includes a rocker joint where the radius of the curvature of the rolling surface of the joint pin is greater than that of the rocker pin.

Rocker joint silent chain having a joint pin thicker than a corresponding rocker pin

A power transmission chain reduces the chordal motion, or up/down motion, of the chain, which permits a reduction in the noise of the chain. In the chain, the inside flank and outside flank of the link teeth are formed to satisfy P.sub.2 .gtoreq.P.sub.1 .gtoreq.P.sub.3 and R.gtoreq.2.times.P, when P.sub.1 is the pitch between the outside flanks on the mesh pitch line of link plates 2, P.sub.2 is the pitch between the inside flanks of two other adjacent link plates that engage with teeth of the links when the chain is stretched nearly straight, and P.sub.3 is the pitch between the inside flanks when the chain is wrapped around the sprocket. R is the radius of curvature of the inside flank and P is the chain pitch.

Power transmission chain

A low noise chain drive of this invention includes toothed sprockets and an endless silent chain having sets of link plates successively connected for articulation by means of connecting members. Each set has a plurality of transversely aligned link plates with each having a pair of link plate teeth designed to engage the sprocket and a pair of openings through which the connecting members are inserted. The link plate teeth are defined by an outside flank and an inside flank. The sprocket has sprocket teeth defined by a sprocket tooth flank. The sprocket tooth flanks and the outside flanks are profiled such that the outside flanks have a swelling located between the tip of the link plate tooth and a point that is in contact with the sprocket tooth after the completion of the engagement. The swellings are formed such that when one link plate set rotates around a rotational axis relative to the preceding set having completed the engagement with the sprocket, the swellings of the one link plate set project outwardly from a circle defined by the minimum radius centering on the rotational axis and osculating the sprocket tooth flank to be meshed with the outside flank located on the trailing side of the one link plate set. The link plate teeth stay in sliding contact at their outside flanks with the sprocket teeth from the beginning of their engaging process through its completion to thereby ease engagement impacts and noises.

Low noise chain drive

In a silent chain, guide link plates are installed in a row along the sides of the link plates. The guide link plates are provided with central openings having rounded corners. The width of the inner beam portion of the central opening is limited by the inner edge of the central opening and the inner edge of the guide link. The width of the outer beam portion of the central opening is limited by the outer edge of the opening and the outer edge of the guide link plate. The width of the inner beam portion is equal to or less than the width of the outer beam portion. Alternatively, the guide link plates are provided with slits extending from the inner edge, and the inner edges of said slits are curved.

Growing community of inventors

Nabari, Japan

Tetsuji Kotera