Lightweight Study On The Driving Axle Housing Of Tractor

With the increase of car ownership and market share,the problem of fuel consumption and pollution has attracted the attention of the government and automobile enterprises.The analysis results show that vehicle weight reduction by 10% can reduce fuel consumption by3.5-6%.The reduction of sprung mass can also improvethe stability and comfort of vehicle.Lightweight design through structural optimization will greatly reduce the use of materials and reduce costs.Because of the advantages of automobile lightweight in energy saving,emission reduction,performance improvement and cost reduction,it has become an important way for the automobile industry to improve the development ability and product competitiveness of its own brand automobile.The axle housing is an important part of automobile chassis,so the research on the lightweight of the axle housing is also very important.In this paper,the finite element analysis,size optimization and bench test of the axle housing are studied.(1)The structural performance and life of the driving axle housing decide whether it can be optimized or not.Therefore,it is necessary to check the rigidity,strength,frequency and fatigue life of the finite element model of the axle housing.The three-dimensional model of the driving axle housing is created by CATIA,and then pre-processed in HyperMesh to create a finite element model,static strength and stiffness analysis of the finite element model of the driving axle housing is carried out.The results show that the maximum stress is 407 MPa,which is located at the hub axle tube,far less than the allowable stress of the material;the maximum deformation per meter wheel spacing is 1.42 m m/m,less than 1.5 m m/m specified in the standard;the first 12 natural frequencies of the driving axle housing are extracted,and the 7-12 natural frequencies of the driving axle housing are higher than 50 HZ.The excitation frequency of the ground to the vibration system is satisfied with the dynamic characteristics of the structure.Based on nCode DesignLife software,the fatigue life of drive axle housing is analyzed by nominal stress method.the minimum fatigue life of the driving axle housing is about 1.61 million times,which meets the requirements of the fatigue test evaluation index of the driving axle housing and can be used for structural optimization.(2)Size optimization method is used to optimize the drive axle housing.The size of each component was taken as optimization variable,the volume of axle housing assembly was minimized as objective,and the yield strength of material is the constraint.After six iterations,the optimal dimension of each component was obtained.At this time,the mass of axle housing assembly was optimized from 202.117 kg to 152.042 kg.It reduces 50.075 kg and weight loss reaches 24.78% of the total weight.The size of the driving axle housing is replaced by a new dimension Material with higher strength which does not meet the requirements is selected,and then static strength,rigidity,stiffness,modal,fatigue analysis is carried out.The results show that the maximum stress and displacement are both under impact condition,and the maximum stress is 372.7 MPa,which appears near the wheel spacing line of hub axle tube,much less than the allowable stress of hub bearing 653 MPa,and the deformation of wheel spacing per meter is 1.47 m m/m,which meets the requirements of national standards.The natural frequency of the 6 order is far greater than that of the pavement frequency 50 HZ,which meets the requirements of dynamic characteristics.The fatigue life is 1548,000 times,which is much larger than the median fatigue life value stipulated in the standard.So the rigidity,strength,frequency and fatigue life of the driving axle housing meet the requirements.The size optimization of finite element simulation is feasible.(3)The driving axle housing assembly was manufactured by stamping,shaping,welding and installing accessories on steel plate.The vertical bending fatigue,rigidity and strength bench tests were carried out on the driving axle housing samples by hydraulic fatigue testing machine.The results show that the rigidity,stiffness,strength and fatigue life of the optimized driving axle housing can meet the service standards.The optimization method is feasible,and the finite element analysis results are very close to the bench test results.