Abstract: A silent chain is provided, which can avoid impinging contact between guide plates and sprocket teeth and prevent wear loss and noise. A guide plate includes a main guide part formed on a side that engages with a sprocket, and an additional guide part formed on at least one of front and rear edges in the longitudinal direction of the chain. The additional guide part protrudes more in the longitudinal direction of the chain than an outer flank of a middle plate arranged in the same guide row and has a size that allows the additional guide part to overlap a sprocket tooth in the chain width direction when engaged with the sprocket S.

Abstract: A silent chain is provided, which can avoid impinging contact between guide plates and sprocket teeth and prevent wear loss and noise. A guide plate includes a main guide part formed on a side that engages with a sprocket, and an additional guide part formed on at least one of front and rear edges in the longitudinal direction of the chain. The additional guide part protrudes more in the longitudinal direction of the chain than an outer flank of a middle plate arranged in the same guide row and has a size that allows the additional guide part to overlap a sprocket tooth in the chain width direction when engaged with the sprocket S.

Abstract: The pins of a roller chain or rollerless bushing chain for an automobile engine are subjected to chromizing treatment that forms a two part outer layer having a thick inner section composed primarily of Cr7C3 and a thinner, outermost, layer composed primarily of Cr23C6. The outer layer has convex protrusions and concave recesses. The protrusions are partially removed by barrel polishing to a level such that the depth of each recess is sufficient, but not substantially greater than necessary, for an inclusion received therein to be substantially entirely below the outer surface of the pin, thereby making the surface pressure exerted by portions of the pin on a surrounding bushing substantially as small as possible without exposure of inclusions beyond the outer surface of the pin.