Vibration Analysis And Optimization Design Of Automobile Gearbox

Automobile gearbox is important changing speed transmission actuator; its ownvibration and work performance directly affect the comfort and safety of automobiledriving. Vibration analysis and optimization design of automobile gearbox that helpsreduce the vibration and noise has important practical significance.The current domestic and international development status and development trendof the automobile gearbox are researched; the basic structure and working principle ofthe gearbox are stated. For gear transmission system, its internal dynamic excitationsare analyzed, including the stiffness excitation, the error excitation, the meshing impactexcitation; further the dynamic models of gear transmission are built, including thetorsional vibration model of gear’s transmission, the bending and torsional vibrationmodel of spur gear’s transmission system, the coupled vibration model of helical gear’stransmission system, and the dynamic equations of those models are listed. Based on thetheoretical knowledge of the modal analysis and the modal superposition method of theresponse to solve, the modal analysis of a pair of gears meshing system is establishedand natural frequency and mode shapes are acquired by the ANSYS Workbenchsoftware; further, the gear system transient dynamic analysis is established and theresponse of the system has been solved. Above-mentioned contents provide a theoreticalbasis for the research of the system dynamic performance, the computation of dynamicstrength, the modification design of tooth edge.On the basis of finite element analysis of these, the overall dynamics simulation ofone automobile gearbox is established and the optimization of one is made. Its shafts,gears, synchronizers, bearings are built, using MASTA software. The stiffness matrix,the mass matrix and the position information of aggregation nodes of bearing bores areextracted by the Workbench and imported in MASTA to assemble the housing; thepower flow and the load spectrum are built, and power flow analysis is made; thedeformation analysis of system are acquired by working load spectrum, including thefatigue safety factor of the shaft, the safety factor, the injury rate and the amount ofdislocation of the gear. Further, the NVH simulation analysis of the gearbox is made;the analysis of the coupling modal and the gear whistle are made in the first workingcondition. In addition, for the system deformation analysis, the macro parameteroptimization of the reverse gear is made, and the safety factor and the injury rate of it are improved, according to the strength requirements. Based on the dynamic analysis,the modification research of the gear of the input shaft is made to improve the loaddistribution of gear and transmission error. In summary, the experimental analysis datais provided for the future research of the auto gearbox, especially experimental studies.