Research object of gear vibration noise in manual transmission

The main research object is the transmission of a medium-sized commercial truck, which contains six gears, and the fifth gear is direct gear. The research goal is to reduce the vibration and noise of the transmission assembly through the simulation of the transmission and the optimization of the gear and the improvement of the box. The research method is to use romaxdesginer, ABAQUS and LMS Virtual.lab The calculation and Simulation of the gear transmission system and the box are realized respectively by using the software, and the specific scheme is determined to improve the vibration and noise of the transmission.

1) Using the software of RomaxDesigner, the numerical simulation, simulation and optimization of the transmission gear transmission system are carried out. The simulation content includes the simulation of transmission error curve, transmission error peak and peak value, maximum contact stress of gear and gear load. After that, the simulation data are analyzed, and to reduce the peak value of transmission error and the maximum contact stress of the gear, improve the transmission error curve and gear load situation as the simulation objectives, through the gear modification method to optimize the target. Finally, the feasibility of the optimization scheme is verified by comparing the simulation data before and after optimization.

2) The modal analysis, frequency response analysis and harmonic response analysis of the transmission case are completed in ABAQUS. Among them, modal analysis determines whether resonance occurs by comparing natural frequency with meshing frequency; frequency response analysis is used to extract the parts with larger vibration velocity and vibration acceleration under resonance frequency; harmonic response analysis takes vibration velocity of box surface as output value, and its results are not used as input document of subsequent sound field analysis.

3) On the premise of modal analysis and vibration response analysis, the output file of harmonic response analysis is imported into LMS Virtual.lab Acoustic analysis is carried out in acoustic analysis module. Through the direct boundary element method, the surface sound pressure level of the box, the sound pressure level of hexahedron and the sound pressure level of independent measuring points are obtained. Then, the box model is divided into several panels according to its characteristics, and the contribution of each panel to the measured point is calculated. Finally, combined with modal analysis, frequency response analysis and acoustic analysis to determine the location of the box that needs to be improved.

4) The corresponding improvement measures are adopted for the improved position, and the modal analysis, frequency response analysis and acoustic analysis of the improved box are carried out. Finally, the feasibility of the improved scheme is verified by comparing the simulation data before and after the improvement.

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