Comprehensive diagnosis and analysis of spur gears with pitting-crack coupling faults

Abstract

As an important part of power transmission in mechanical system, the health status of gear needs to be judged accurately. However, most of researchers focus on single fault gear, and very few papers are reported on the performance of multiple faults. So the gear mathematical model with pitting-crack coupling faults is derived in this study, and it is validated by a three-dimensional finite element model. Furthermore, several types of fault combinations from health to severity are presented to investigate the effect of coupling fault evolution on gear time-varying meshing stiffness. The stiffness excitation is applied into an 8 degrees of freedom model to obtain the dynamic characteristics of the gear-rotor system in terms of displacement and acceleration, and a reasonable diagnosis of the gear status can be made by analyzing the dynamic characteristics in time domain and frequency domain. In the next step of research, the statistical indicators are applied to further reveal the degree of coupling faults, which provides effective reference on the diagnosis of coupling fault gears.