Detection of gear pitting failure progression with on-line particle monitoring

Macroscopic pitting is a common gear flank failure mode. The determination of pitting life is done experimentally and the formation of macropit is typically followed by regular visual inspections and photographing of tooth flanks, which is time consuming and gives limited information about progression of failure. In this study, the progression of gear macropitting was detected with on-line particle monitoring from lubricating oil together with vibration monitoring and visual inspections. The tests were carried out with case-hardened gears under heavy loading condition. The results show that the concentration of metallic particles in oil correlate well with the severity of macropitting obtained from the visual inspection. Vibration acceleration descriptors indicating peaked signal correlate also with the wear of gear contact.