Influence of time-varying excitation on vibration characteristics of the spiral bevel gear transmission system with pitting faults

Time-varying mesh stiffness (TVMS) may cause noise and vibration in spiral bevel gear (SBG) transmission systems due to its role as an internal excitation source. Pitting faults as a typical mechanical fault can make TVMS reduce and alter the vibration characteristic of the SBG system. This paper aims to address the issue of unclear vibration characteristics of SBG systems. Firstly, an eight degrees of freedom (DOFs) dynamic model for SBGs with pitting defects is developed. An analytical model utilizing the slice strategy is proposed to evaluate the TVMS of SBG with pitting faults. The pitting fault is accounted for the dynamic model by incorporating the pitting faults into the evaluated TVMS. Then, the vibration responses of SBGs with tooth pitting can be obtained and the responses in both the time and frequency domains are analyzed. The analysis shows that pitting faults can make periodic impact in the time domain and enhance the energy in low frequency region and its influence on the meshing frequency is not remarkable. Finally, the experiment results are analyzed to verify the proposed dynamic model.