Modelling a timing belt pitch

Grzegorz Domek,Michał Wilczyński,I Malujda,D Wojtkowiak,K Talaśka,D Wilczyński,M Berdychowski,M Dudziak,Ł Warguła,P Krawiec,J Górecki

doi:10.1051/matecconf/201925401011

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.

Highlights

The beginnings of timing belts development in the last century were rich in structural and material solutions [1, 2]
Consecutive types of timing belts were characterized by different geometrical dimensions expressed in inches, as first synchronous belts were developed in the USA at UNIROYAL company
In response to the dynamic development of timing belts applications in bicycle transmissions, one of the leading manufacturers proposed an untypical pitch of 9 mm (Fig. 2). This was explained by the possibility of optimizing the pitch for products manufactured in large quantities. This opens a discussion on the modelling of the geometric form of a timing belt and the significance of the pitch for the properties of the synchronous transmission gear [5, 6]

Summary

The construction of the timing belt

The beginnings of timing belts development in the last century were rich in structural and material solutions [1, 2]. Consecutive types of timing belts were characterized by different geometrical dimensions expressed in inches, as first synchronous belts were developed in the USA at UNIROYAL company Intense development of timing belts applications prompts manufacturers to make attempts to design “special" belts for "individual" application in the system, which are manufactured in mass production [3, 4]. In response to the dynamic development of timing belts applications in bicycle transmissions, one of the leading manufacturers proposed an untypical pitch of 9 mm (Fig. 2). This was explained by the possibility of optimizing the pitch for products manufactured in large quantities. This opens a discussion on the modelling of the geometric form of a timing belt and the significance of the pitch for the properties of the synchronous transmission gear [5, 6]

Belt design methods

Conclusions