Evaluation of lubrication conditions in gear contacts using contact resistance and bulk temperature measurements

Abstract

Lubrication conditions have a major effect on lifetime and friction in gear contacts. Monitoring of relative changes in protecting film thickness provides an opportunity to understand the operating conditions before an initial fault appears. In this study, the lubrication conditions were detected on-line using contact resistance and bulk temperature measurements, which were applied to a modified FZG gear test device. Measurements were made with polished gear surfaces at operating conditions that are typical of industrial gears. The presented mean contact resistance includes the data points in different positions along the line of action and thus also considers transient effects. The bulk temperature and trend curves of the mean contact resistance at different pitch line velocities, loads, and oil inlet temperatures are reported and discussed as measures for analysing the lubrication condition.