Sound-radiation analysis system and design of a low-noise gearbox with a multi-stage helical gear system

The increasing demand for quiet gear systems has created the need for precise analysis of gear-drive vibration. Furthermore, these days, noise should be predicted during product design. In response to these needs, the authors have developed a new method for predicting the vibration and noise of a total gear system, including not only multi-stage gear pairs but also shafts, pedestals, and a gearbox. The method consists of three separate analyses: three-dimensional gear-vibration analysis. FEA (finite element analysis) of gearbox vibration, and BEA (boundary element analysis) of the sound field. To verify the effectiveness of the method, sound-pressure levels at two points in the horizontal and the vertical directions from the experimental apparatus's gearbox were measured. These measurements agreed well with the corresponding calculated levels by developed analysis method. It can thus be concluded that the method can accurately predict vibration and noise and sufficiently assess the noise radiated and propagated through air. It can therefore be utilized for designing a low-noise gearbox by determining the area from which the noise is radiated intensively.