Experimental Analyses of Vibration and Noise of Faulted Planetary Gearbox

ABSTRACT Epicyclic gear trains are widely used in various industrial sectors due to their advantages over fixed-axis gears, such as high torque capability, compact size, differential and planetary designs, ease of adjusting gear ratios and even directions of rotation. This research focuses on planetary gearbox whose degree of freedom is one. The geometry and dynamics of the planetary gear train are quite complicated compared with the fixed-axis gear train. In an earlier research, three theoretical models for faulted sun, planet, and ring gears were analyzed and the signature frequencies of the three cases were derived. In this paper, experiments were conducted on a Drivetrain Diagnostics Simulator with various faults of the sun gear in order to verify the previously proposed theoretical models. Both the vibration and noise signals were collected and analyzed using signal processing techniques in the time and frequency domains. The sidebands around gear mesh frequency due to the fault signature frequencies are also discussed accordingly. The signals of healthy and faulted gear trains were also compared carefully. The existence of the signature frequency can be used to detect mechanical defects and prevent catastrophic consequences.