Vibration characteristics and condition monitoring of internal radial clearance within a ball bearing in a gear-shaft-bearing system

Internal radial clearance is a key factor influencing bearing fatigue life. Moreover, bearings inevitably suffer from various wears and tears, which result in gradual increase of shorten Monitoring changes using vibration can effectively indicate the wear provide good leading time to perform maintenances. Previous studies show that at ball pass frequency on outer race (BPFO) be based for monitoring. However, such induced has not been well understood, especially under complicated dynamic interactions as gearbox system. To fill this gap, paper presents nonlinear gear-shaft-bearing-housing model with fourteen degree freedom (DOF) investigate responses gear meshing force progressively changed clearances first. Then, was verified through two-stage spur gearbox. Furthermore, characteristics different influence are revealed indicator modulation signal bispectrum-sideband estimator (MSB-SE) proposed. Finally, data run-to-failure test rig utilized verify effectiveness MSB-SE Simulation results BPFO modulated (GMF) amplitude envelope spectrum increases meshing. Indicator MSB-SE, possessing capability purifying interferences strong noises, effective capture variance clearances. The experiment provided evidence proposed indicator, more accurate than conventional analysis time-domain indicators, RMS kurtosis. These findings significance fault diagnosis maintenance.