Analysis on vibration transmission characteristics of box-like power structure

Box-like dynamic structures are proceeding at the direction of maximization and flexibility. Vibration transmission characteristics of geared shaft-bearing-housing were studied by finite element method under different excitation conditions for two-stage reducer. Gearbox was used as a flexible substructure reduced to the center of bearing hole by Craig-Bampton dynamic reduction technique. When mesh transmission error and torque fluctuations of input shaft served as excitation source respectively, meanwhile nonlinear factors such as time-varying meshing stiffness, meshing misalignment, gear tooth backlash, axial contact ratio, and the gravity effect of shafts and gears were taken into consideration, dynamic acceleration response at gearbox reduction nodes and bearing inner ring were analyzed based on the thought of shaft section node. Finally, the natural frequencies of gearbox were extracted based on Block Lanzos method. Numerical analysis results show that the bearings of output shaft do not play an attenuation effect in the process of dynamic response transmission, and should be replaced to prevent the influence on the performance of whole system. Gearbox is conservatively designed that needs to be optimized according to the dynamic response of gearbox reduction nodes.