Gearbox noise reduction based on modal acoustic contributions

Radiated noise of a gearbox with a double helical gear system was calculated using FEM/BEM and the influences of modal shapes on the radiated noise were analyzed. The modal participation factors and modal acoustic contributions of each mode were calculated and the mode having the maximum contribution to the radiated noise of the input and output field points was found. The reasonable arrangements of ribs and isolation masses were proposed according to the analysis of modal acoustic contributions. The results showed that the flexural vibration of the gearbox housing has most obvious effects on the radiated noise; when the mode having the maximum acoustic contributions is determined, the positions on each panel having obvious flexural vibrations can be added with ribs or isolation masses, the radiated noise of field points at the same side of panels can be reduced obviously.