Dynamic modeling of a planetary gear system with sun gear crack under gravity and carrier-ring clearance

摘要

The large load capacity, compact size and high-power density have made planetary gearboxes widely applied in heavy machinery such as wind turbines. Although well designed, planetary gearboxes are vulnerable to fatigue crack because of harsh working environment such as high loads. Fatigue crack may eventually cause failures of planetary gearboxes if not detected early. This study investigates the dynamics of a planetary gear system with a crack in a sun gear tooth. This paper considers the gravity effect, carrier-ring bearings clearance, gyroscopic and centrifugal forces that reported studies have not considered together yet. Simulation results reveal that gravity produces a sinusoidal shift in the dynamic response of a planetary gearbox in the time domain. The carrier-ring bearing clearance causes crack-induced impulses to be more apparent. These results can help researchers develop more effective fault diagnosis strategies especially for early crack in the sun gear.