Fundamentals of Sprocket Design and Reverse Engineering of Rear Sprocket of a Yamaha CY80 Motorcycle

摘要

The sprocket is a very vital component in the transmission of power and motion in most motorcycle; there is always a pair (rear and front) in a motorcycle. The front sprocket drives the rear sprocket via chain connection. They exist in various dimensions, teeth number and are made of different materials. This study involves the fundamentals of sprocket design and manufacturing of a Yamaha CY80 motorcycle rear sprocket through reverse engineering approach. It discusses dimensioning, drafting, chemical composition, material selection, choice of manufacturing process, heat treatment, surface finish and packaging as the eight steps that need to be followed sequentially in this reverse engineering approach. In this work, universal milling machine was used to produce the sprocket from the blanked medium carbon steel (AISI 1045) with chemical composition of C=0.45%, Mn=0.75%, P=0.03% max, S=0.04%. Induction heat treatment was applied to move the material hardness from 13 HRC to 45 HRC as shown by hardness test.