Research on time-varying mesh stiffness and vibration characterization of herringbone gear planetary transmission system with crack-pitting coupling

To investigate the vibration characteristics of the herringbone gear planetary transmission system (HGPTS) with crack-pitting coupling factors, a 55-DOF bending-torsion-axle-pendulum (BTAP) coupled dynamics model of the drive system is established. This model accounts for the effects of errors, time-varying mesh stiffness (TVMS), torsional stiffness, support stiffness, and retract groove. In the model, the TVMS of the sun and planetary herringbone gear pair is calculated, considering crack-pitting coupling using the potential energy method and the slicing method. The dynamics model is solved using the Runge-Kutta numerical integration method, yielding the time-domain and frequency-domain responses of the drive system under different degrees of crack-pitting coupling. The analysis focuses on the vibration response of the system due to changes in crack-pitting coupling. Additionally, vibration tests are performed to assess the impact of different crack-pitting parameters on the system’s time-frequency response characteristics. The results show that the time-domain response of the system, influenced by crack-pitting coupling, is characterized by periodic impact behavior, which becomes more pronounced as the degree of crack-pitting coupling increases. In the frequency domain, the system’s response exhibits failure frequency phenomena, with noticeable side-frequency signals near the octave frequency. These signals worsen as crack-pitting coupling increases, leading to a deterioration in the vibration stability of the system. A comparison between experimental data and theoretical results shows good consistency, validating the correctness of the model. This research provides a theoretical foundation for fault diagnosis as well as the operation and maintenance of the system.