| With continuous advancement of agricultural production toward modernization and mechanization in our country,a series of agricultural machinery industries have gradually developed and expanded.The tractor,as the most widely used agricultural machinery,meets higher requirements on their performance in accordance with market demand.As the main transmission and load-bearing components of the tractor,the tractor steering drive axle performance has a direct and important influence on the performance of the whole vehicle.At present,the researchers in China aim at improving the researches on the small and medium-sized tractor drive axle compared with foreign mature products.There is no research on the strength of the drive axle under internal forces in domestic research,and there is no research on the dynamic strength of the drive axle based on the road information spectrum.In this paper,a 35 horsepower tractor steering drive axle is taken as the research object,and the dynamic and static characteristics of it are analyzed by finite element analysis to carry out an optimal design of the drive axle structural parameters.The reliability of the simulation result is verified by the comparative analysis between the static strength test and static simulation.The main research contents are as follows:1.The finite element analysis are performed on the important parts of the drive axle after the three-dimensional modeling.Through the analysis of the axle housing and the steering knuckle,the internal forces are loaded to make sure the loading conditions closer to the actual working conditions.The results show that the maximum stress of the drive axle housing,gear transmission system and steering knuckle is less than the yield limit of the material,the static strength of the drive axle meets the requirements.In addition,we can find some parts where the large deformation or fracture may occur in the process of using the stress cloud diagram.2.The modal analysis of the axle housing of the drive axle is carried out,the natural frequency and model shapes of the first 6 order of the drive axle under the restrained condition are studied.The first-order natural frequency is higher than the possible excitation vibration frequency,which can avoid the occurrence of resonance.In addition,the local model shapes is less,which shows that the overall stiffness of the drive axle is better.The harmonic response of the axle housing in the first order natural frequency is studied,and the stress and deformation of the axle housing are significantly different from that of static load.The 3 times full impact load and the dynamic loads based on the road surface information spectrum are respectively applied to the axle housing of the drive axle.Through the simulation analysis,the drive axle stress and deformation under the dynamic loading are obtained which verify that the dynamic strength and the dynamic characteristics of the drive axle meets the requirement of using.3.According to the structure design of the steering drive axle,the frock clamp and the device of torque are trial-manufactured;the static strength test is carried out by strain electrical measurement.The strength tests are performed for single full gravity load with and single torque load,3 times full gravity load with and 2 times torque load.This experiment verifies that the strength of the drive axle meets the requirement of using.The average relative error between test results and simulation results is 17%.This result verifies the reliability of the finite element simulation results of drive axle.4.Make an optimal design on the drive axle housing.The topology optimization and size optimization of the drive axle housing are carried out on the basis of three times dynamic full gravity load.According to the optimized design results,this research reduces the thickness of the axle housing,thus reduce the overall weight by 5%.The static finite element simulation results show that the material distribution of the steering drive axle is more reasonable. |
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