Low noise chain

摘要

A barrel-shaped coil spring roller is formed by closely winding spring wire rods having fine crepe-like concave-convex surfaces on the surface of the barrel-shaped coil spring roller. The fine crepe-like concave-convex surfaces serve as a lubricating oil reservoir and are formed by a shotpeening process. Lubricating oil is retained on the fine crepe-like concave-convex surfaces formed by the shot-peening process. Sliding noises between the spring wire rods adjacent to each other, which noises are generated by elastic deformation of the barrel-like coil spring roller when in engagement with the toothed surface of the sprocket, are reduced by the lubricating oil. The wear on both of the barrel-shaped coil spring roller and the sprocket is lessened and the power loss is reduced. The low noise chain is capable of retaining a lubricating oil on the surface of spring wire rods of a barrel-shaped coil spring roller for long periods of time, while still maintaining a noise reduction effect.