| Wheel hub,as the main load-bearing part of the whole vehicle driving system,is the most important safety part affecting the mechanical performance of the whole vehicle.Its lightweight level and mechanical performance directly affect the stability,safety,braking and economy of the vehicle.In order to meet the market demand and performance requirement,save cost and improve product competitiveness,lightweight and high-performance wheel hub has become the development goal of the industry.However,the structural features of the wheel hub are complex,and the loading types of different regions including spoke,rim and flange are different,and its function and process constraints further restrict the lightweight process.As a result,the design and optimization of wheel hub is mainly based on engineering experience for trial and error research,which is expensive and time-consuming.So,the theory and method of lightweight design for the wheel hub still need to be improved.This study aims to break through the technical bottleneck in the process of structural design for the ultra light,high performance and fatigue resistant wheel hub,and some key problems including shape optimization of wheel rim section,layout design of reinforced ribs and topology optimization of wheel spoke are studied.Finally,a set of effective theoretical guidance for the structural design and optimization of wheel rim and spoke is provided,so as to realize the lightweight design of wheel hub.The main research work includes:(1)The structural features and processing technology of aluminum alloy wheel hub are analyzed,and the main load-bearing regions and types under various test conditions are studied.Based on TRIZ theory,the main technical contradictions in the process of lightweight design for the wheel hub are analyzed and the corresponding principle of invention is studied.The optimization scheme is established to provide the foundation for the lightweight design of wheel hub.(2)An shape optimization method of wheel rim section based on load path analysis is proposed.The explicit expression method of load transfer law of wheel rim section is studied.The evaluation strategy of structural load-bearing performance is formulated,and the load-bearing performance of wheel rim section is analyzed and evaluated.The shape optimization suggestions of wheel rim section and the determination method of dimension parameters are given.Simulation analysis,static pressure and radial impact test are carried out to verify the effect of shape optimization.The method provides a theoretical basis for the design and optimization of wheel rim.(3)The lightweight design idea of skin & reinforced ribs is put forward at the first time.The minimum wall thickness of skin and the layout design requirements of reinforced ribs are studied.The layout design idea of reinforced ribs based on bionics is given.The honeycomb structure and vein branch structure are selected as bionic prototype to design the layout of reinforced ribs.The mechanical performances of three schemes including honeycomb like rim,branch rim and hybrid bionic rim are analyzed and the lightweight effect is verified.(4)The influence law of the number of spokes on the casting process and mechanical performance of wheel hub is studied,and the selection suggestions of the number of spokes are given.The load-bearing performance of wheel spoke under multi-working conditions and multi-position is analyzed,and the topology optimization hierarchical structure model is established.The multi-objective comprehensive evaluation function is established to represent the dynamic rotation process of the spoke.And the mathematical model of multi-objective topology optimization is established to carry out the lightweight design of wheel spoke.(5)The three-dimensional model of lightweight aluminum alloy wheel hub is provided and its mechanical performances are verified by simulation analysis.The idea of fatigue life prediction of wheel hub is given.The SN curve fitting and average stress correction method of wheel hub are studied,and the fatigue life prediction model considering the dynamic rotation characteristics is established.The rationality of prediction model is verified by experiments,and the fatigue life prediction is realized. |
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