The Research On Structural Noise Prediction And Improving Design Of Gearbox

The gear box has been widely used in the field of mechanical transmission for its advantage of high efficiency, compact structure, stable transmission ratio and long life. With the rapid development of modern industry, higher speed, more highly efficiency and bigger power has become the final aim of the gear transmission, so that the gearbox vibration and noise problem has become particularly prominent. In order to effectively control the vibration and noise of gear box, the research on the prediction of structure noise of gear box with the finite element method(FEM) and boundary element method(BEM) has been conducted systemically, and the gearbox structure noise has been predicted, in terms of which some reasonable structural improvements has been proposed.In this paper, a transmission gearbox of a vibration test-bed is for research, based on multi-body dynamics theory, ADAMS / Flex flexible body analysis module is used to simulate the gear transmission, thus to determine the gear meshing force. Solve the inherent characteristics of gear box with the finite element analysis method, and get the dynamic response of the gearbox with the result of the simulation of gear transmission. The structural noise of the gearbox will be predicted by the boundary element method with the result of the dynamic response. The predicted result is verified by sound intensity measurement, in terms of which the structure improvements are made for the noise control.The specific tasks of study are as follows:(1)Simulation of meshing gears incentives. The physical model of gear transmission system is established by the software of Solidworks, and flexible gear transmission system model is made by ANSYS. Then the meshing force of the gear transmission is obtained after the dynamic analysis of flexible gear transmission system.(2) Modal analysis of the gearbox. The solid model of the gearbox is imported into ANSYS and then meshed. After the modal analysis the natural frequency and vibration mode are obtained, which is the base of the dynamic response analysis.(3) Dynamic response analysis and noise prediction of the gearbox. The results of modal analysis and dynamic simulation of meshing are used to solve the dynamic response. The boundary element model of gear box is created by ANSYS and then is imported into SYSNOISE. With the boundary conditions of dynamic response results acoustic response characteristics will be obtained by BEM. (4) Sound intensity measurement. Sound intensity measurement of the test-bed on which the gearbox seated is carried out. Measuring plane envelopes the whole test-bed, despite there are other sounds in the envelope, the main frequency of sound sources is obtained by the method of covering the source respectively, thus the result of prediction is verified.(5) Improving design of the gearbox. Some improvements have been made out to reduce the vibration and noise in terms of the results of the prediction and structural dynamic response.