Contact point of bush - sprocket tooth depending on pitch differences of bush chain transmissions

Abstract

Chain transmissions have a large use in industrial applications. The study of kinematics and dynamics of this kind of transmissions has a lot of space to cover due to different type of chains, different geometries, standardized or not, or even different ISO and AGMA standards. This paper is referring to the bush chain transmission based on ISO standard for geometry and dimensions. The pitch of the chain is bigger than the pitch measured on the sprocket and the difference must be in a certain range. Depending on this difference, the contact point between bush and the tooth varies. It also varies depending on the position around the sprocket. All these are influencing the dynamic of the chain transmission and the friction losses. The paper analyses the kinematics of chain link depending on the rotation angle of the sprocket (θ), establishing the contact point between bush and tooth, for a given tooth profile dimension and pitch differences. An important result is the point of entering in contact between bush and sprocket tooth with an influence on the normal and transversal forces in the chain. The results of numerical simulations are the base of drawing conclusions and recommendations on the pitch differences considering criteria like minimum friction and minimizing the transversal vibration.