Research On Vibration And Noise Reduction Of SEM30 Gearbox Based On Constrained Damping

SEM30 gearbox is fixed shaft type and has been widely used in complex working condition of mine bulldozers and other engineering machinery with its simple structure, high transmission efficiency, stable transmission ratio and the advantages of long service life. But the vibration and noise problems appear in the work process, the noise value exceeds the national standard limit value, seriously affect the normal work of engineering machinery and the health of the operator. By increasing the stiffness and the damping of the gearbox or improve the machining precision of gear have failed to control the noise effectively. In this study, the method of plate contribution analysis is used to identify the source of noise. The method of increasing the rigidity and damping of the gear box is used to optimize the design of the gear box and this has important theoretical value and engineering application value for reducing the vibration and noise of gear box. The main work is as follows:Perform the multi-body dynamics of the gear transmission system using Adams, and get the gear meshing impact excitation. Do the modal analysis and dynamic response analysis of gear box based on the finite element method with the excitation, and get the dynamic characteristics of the gear box. The gear meshing frequency is closed to the sixth order natural frequency of gearbox at the speed of 1500r/m, and the vibration of gear box is increasing; calculate the vibration radiated noise of the gearbox based on the boundary element method based with Virtual.Lab, obtain the sound pressure level and sound power level contour curve, the noise of gear box reaches peak at the meshing frequency; to decide which panel is the weakest, preform the analysis of plate contribution base on acoustic transfer vector method, and the source of the gear box is found out, and provide the basis for optimal design of gear box. As the constrained damping structure can dissipate more energy than free damping structure, so use constrained damping structure to perform the optimal design of the gear box. Use of Design Exploration module in Workbench, and chose the direct optimization method, the minimum vibration acceleration of the gear box surface as the optimization objective, the constrained damping structure dimensions such as thickness of damping layer and meshing force as optimization variables, to perform the iterative calculation, and get the optimal size of the constrained damping structure. Verify the radiation noise of gearbox according to the optimal size, the calculation results show that the vibration of gear box based on constrained damping structure has been significantly reduced compared with the original structure, constrained damping structure to achieve the effect of reducing vibration and noise is effective.