Investigation On Noise Control Of Gearbox Based On Sound Transmission Analysis

Gearbox is widely used in machinery and equipment as power and motion transmission structure. But its vibration and noise problem is very difficult to solve and investigated by many researchers. In this paper, the vibration and noise of gearbox on a vibration test-rig is investigated to effectively reduce noise emission:1) Modal testing and noise data acquisition for the gearbox; 2) Noise prediction of gearbox based on multi-body dynamics, finite element model(FEM) and boundary element model(BEM); 3) Identification the main noise source by using Acoustic Transfer Vector (ATV) and Panel Acoustic Contribution Analysis (PACA) Methodology; 4) Reduction the gearbox noise by modified structure.To solve the problem of gearbox vibration and noise, panel acoustic contribution analysis is investigated and improved. The Panel Acoustic Power Contribution Analysis (PAPCA) is put forward and it will be helpful to solve the limitations of existing methods. The main noise radiation parts are identified by this analysis, and the improvement project basis is provided to reduction the noise of the gearbox. The specific study of this paper as follows:(1)The vibration modes of the gearbox are tested by hammer response. Then the vibration characteristics are preliminary investigated and the FEM can be proved accuracy through the test. The sound pressure, sound intensity and sound power and other acoustic test are also gathered, which could be used for the accuracy analysis of the gearbox noise simulation.(2)A rigid multi-body gear transmission mode including the gear and axis are constructed using ADAMS software to obtain interaction forces for gear transmission systems. FEM of the gearbox is constructed to perform the vibration analysis by the ANSYS software. BEM is constructed to predict the noise by the acoustic software. Correlation analysis between FEM and BEM, and physical measurements proved that the models could be used to predict radiation noise of the gearbox with good performance.(3)The gearbox is analyzed by the ATV and PAPCA. The relationship between the vibration surface and the field point is studied by the ATV, which is the basis of PACA. PACA is used for further analysis. The acoustic pressure contribution of the gearbox panels are analyzed by PACA. At the same time, acoustic power contributions of the panels are analyzed by PAPCA to determine the main noise source.(4)To effectively reduce noise emission, three structure modified design are put forward. It can be concluded that the modified design will help reduce noise emission according to simulation analysis.