ABSTRACT

Gear Micropitting is a contact fatigue failure which mainly appears on teeth flanks of case-hardened gears. This initial failure can lead to larger cracks and eventually to macropitting or spalling which in turn can result in destructive failure. Tooth flank shot peening treatment has been used to increase the fatigue strength of components including gears but to our knowledge, its effect on micropitting has not yet been studied.

A previous CETIM study based on a twin disc machine tests has demonstrated that an appropriate shot peening treatment after grinding could reduce the micropitting phenomenon.

The aim of this paper is on one side to investigate the effect of shot peening on the gear micropitting and its development to macropitting and on the other side to compare the standardized calculation methods for the prediction of micropitting (ISO/TR 6336-22 :2018) and for pitting (ISO 6336-2:2019 & AGMA 2101 D04). The experimental study is carried out using a back-to-back gear test rig. The micropitting initiation and its propagation on the tooth flank was monitored via an interrupted test method. The fatigue tests are run until the appearance of macropitting. A comparison between experimental results obtained on tested gears and theoretical predictions of micropitting and pitting based on ISO and AGMA standards is presented.

Author(s): Dalia Jbily, Luc Amar, André Simonneau

ISBN: 978-1-64353-157-1