CAE Analysis And Topology Optimization Of Gearbox Housing For Pure Electric Vehicles

With the increasing importance of energy issues,energy conservation and emission reduction have received more and more attention in the automotive industry,so pure electric vehicles have developed rapidly.As we all know,the automobile gearbox is the core device of the car transmission system,and the performance of the casing plays an important role in the normal operation of the gearbox.Therefore,the performance of the casing is directly related to the performance of the whole vehicle,and it should be ensured that it meets the requirements for use.In addition,topology optimization as an important means of vehicle lightweighting is also an effective way to save energy and reduce emissions.According to the development requirements of a company's gearbox,this paper takes a new two-speed gearbox with pure electric vehicle as the research object,and studies the gearbox housing from four aspects: structural design,simulation analysis,test verification and optimization improvement.Lightweight is achieved under the premise of increasing the stiffness in the first and reverse gears and the first two natural frequencies of the housing to meet the requirements of use.The main research contents are as follows:1.The research background and significance of gearbox housing of pure electric vehicle are introduced in detail.Then the research status of the transmission of pure electric vehicle is described.Then the research status of the finite element analysis and topology optimization of the housing is introduced.2.The design process of the transmission housing structure is introduced in detail.The geometric model and finite element model of the housing are established by CATIA and HyperMesh respectively.Based on this,static simulation analysis of the first gear and reverse gear of the shell was carried out by using ABAQUS.The analysis results show that the shell meets the rigid strength requirements under two conditions and has an optimized design space.Then,using the combination of simulation analysis and experiment,the dynamic characteristics of the shell were simulated and tested by ABAQUS and LMS.Test.Lab respectively.The comparison between simulation and test results shows that the calculated mode shapes are basically in agreement with the experimental mode shapes in both free and constrained states,and the relative error of the natural frequency is within 4%,which verifies the accuracy of the finite element model of the gearbox shell.In addition,by studying the modal parameters of the shell,it is found that the first two natural frequencies are close to the gear mesh excitation frequency under the common rotating speed,which may cause resonance phenomenon and provide basic data for multi-objective topology optimization.3.Based on the variable density method,a static and dynamic joint multi-objective topology optimization mathematical model is established.Topology optimization is performed by Optistruct.Taking the cell density in the design domain as the design variable,the volume ratio before and after optimization is constrained.The objective of optimization is to minimize flexibility under first and reverse gear conditions and maximize the weighted response of the first and second natural frequencies.The optimization results show that the stiffness and natural frequency of the shell are improved after optimization.According to the topology optimization results,the transmission housing structure is improved.The simulation calculation shows that the improved housing improves the stiffness and the first two natural frequencies,which makes the gear transmission more accurate and avoids the gear meshing excitation frequency under the common rotating speed,and the quality is reduced by 7% after the improvement,its performance is significantly improved to meet the design requirements.