Research On Key Technology Of Lightweight Of Commercial Vehicle Transmission Shaft Assembly

With the rapid development of the automobile industry in China,the increasing number of automobiles has brought a series of environmental problems.In recent years,pure electric vehicles and hybrid electric vehicles have developed rapidly,but due to the limitation of range and charging time,new energy vehicles can not become the main body of the current sales of cars.At present,lightweight design is recognized as an effective means of energy saving and emission reduction adopted by major automobile manufacturers.Automobile lightweight can not only achieve low fuel consumption,less pollution emissions,but also enhance the dynamic response of the vehicle.As the main assembly of the transmission system of commercial vehicles,the lightweight of the transmission shaft is the necessary means and path to realize the lightweight of commercial vehicles.In this paper,the lightweight design of the transmission shaft assembly is carried out by using the method of topological optimization.Firstly,the finite element model of the transmission shaft assembly is established using ANSYS Workbench software.Based on this model,the static strength,static stiffness and fatigue life of flange fork,spline fork and universal joint fork of transmission shaft are analyzed respectively,and the performance parameters of main parts are determined,which further explains the possibility of light weighting of transmission shaft.At the same time,in order to verify the accuracy of the finite element model,the finite element analysis and bench test of the transmission shaft assembly are carried out,and the results of the two are compared and analyzed.Secondly,the static working conditions of flange fork,spline fork and universal joint fork are set up in HyperMesh.According to the coordination mode between the transmission shaft and the external mechanism and the assembly relationship between the components,the design and non-design areas of the main components are set up;the manufacturing process constraints are carried out according to the processing technology and different working conditions in the production of the transmission shaft to enhance the effectiveness of the optimization structure;The maximum stress and displacement in the finite element analysis results of the main parts of the transmission shaft are taken as the constraints.After setting the above parameters,the density function interpolation model is used in OptiStruct to carry out the topology optimization analysis of the main parts of the transmission shaft by using the variable density method of SIMP.According to the current processing level,the cell density threshold of the optimized model is selected to determine the result of the topology optimization.Finally,referring to the topological optimization results of each component,the flange fork,spline fork and universal joint fork are improved respectively.And through analyzing the static force and fatigue life of the improved components and assembly,the results are compared with the performance parameters of the original model.The result shows that the life of the improved model is promoted,the strength and stiffness is basically unchanged,and the weight of the main parts is reduced to varying degrees.