Abstract: A sprocket has a mounting part for mounting on a wheel and a corrugated section provided with teeth for engagement with a chain such that the sprocket has a reduces volume and weight and allows for appropriate engagement with the chain by having the position of the sprocket agree with the position of the chain. The mounting part has a first raised section raised toward a one plate surface side and a second raised section raised toward another plate surface side with respect to a longitudinally central plane extending through a center of the sprocket so as to divide the total volume and weight of the sprocket into substantially equal sections. A flat top part of the first raised section having a mounting hole is on a level with a bottommost end surface of the sprocket.

Abstract: A sprocket includes a body, and teeth formed on the peripheral edge of the body. The teeth have a thickness greater than that of the body. This design enables the use of the existing chain and brings about a reduction in the weight of the overall sprocket.

Abstract: A sprocket 1 includes a wavy region 2. The wavy region is formed at least at the outer periphery of the sprocket and extends in an undulating fashion along the circumference of the sprocket. The wavy region has a plurality of convex joint portions 3. A plurality of teeth 5 are formed at the outer end of the convex joint portions.

Abstract: A sprocket includes a body, and teeth formed on the peripheral edge of the body. The teeth have a thickness greater than that of the body. This design enables the use of an existing chain and brings about a reduction in the weight of the overall sprocket.

Abstract: A rotary member in the form of a sprocket or a brake disc for transmitting a drive force or brake force, the rotary member having an annular hub portion arranged on a center side, an annular ring portion arranged on an outer circumferential side, and a plurality of arm portions connecting the hub portion and the ring portion, with a plurality of weight reduction holes partitioned by the arm portions between the hub portion and the ring portion. The plurality of arm portions are provided so that centers of their distal end portions on the ring portion side and centers of their proximal end portions on the hub portion side are offset in one circumferential direction, respectively, and the hub portion and the ring portion are not directly connected to each other by longitudinal sectional lines that intersect with the arm portions in a radial direction of the rotary member.

Abstract: A sprocket made of low carbon steel of not more than 0.25 wt % in the carbon content comprising teeth portion which are quenched to a hardness close to the theoretical maximum quenching hardness of 35-55 Rockwell hardness C, and an inside diameter mounting hole.