Modelling a timing belt pitch

Abstract

The paper deals with the problem of timing belt pitch significance for the dynamics of a timing belt transmission gear motion. Specific pitches of timing belts have been used for many years. They were previously reserved for belts made of rubber, while another group of pitches was intended for belts made of polyurethane. This division ceased to apply recently, and in addition there are belts with pitches which have not been used before, such as HTD9M or AT15. The paper presents the parameter that makes the pulley diameter and the pitch dependent on the number of teeth involved in meshing (coupling) with a pulley. It is an equivalent of the coverage factor occurring in cylindrical timing gears. Earlier studies on that parameter did not take into account the teeth unevenly spaced over the width of the belt. New pitches of belts may occur in "mass production" applications and they are applied more and more often. Thus it is important to bear in mind the consequences of changing the pitch of the timing belt in transmission gear structures.