Structure Improvement And Performance Study Of Thrust Rod On Commercial Vehicle

The thrust rod is one of the most important parts of the balanced-suspension on theheavy commercial vehicle. It can transfer the longitudinal force, limit the relative positionof the middle and rear axles and isolate the vibration. The various driving conditions andthe hostile using environment lead to the complicated loads on the thrust rod, which alwaysresults in its premature damage. In order to protect the interests of the manufacturers andthe users, how to improve the service life of the thrust rod has becoming an urgent concern.This paper optimized a typical construction of the thrust rod which improved its life as aresult. The study of this paper are as follows:First of all, in order to require the working load of the thrust rod, the force analysis,the simulation analysis and the vehicle test were carried out. Then the results of the threemethods were compared and finally an effective method of calculating the working load ofthrust rod was found. The working load was using as one of input variables in FEA.And then, the FEA of the original structure of the thrust rod was performed. First, thecharacteristics of the rubber which is the most important part of the thrust rod has beenstudied. The material parameters were required and the reasonable constitutive model waschosen. Then, the finite element model was established with the FEA software. At last, thefinite element calculation was carried out and we got the stress nephogram, the strainnephogram and the longitudinal static stiffness and then its strength and stiffness wereanalyzed. Moreover, in order to prove the accuracy of the finite element, we compared theresults of the modal test and the modal analysis and we also compared the results of thestatic stiffness test and FEA.Next, the methods of structure optimization of the thrust rod were proposed. There arefive optimization methods: to increase the external diameter of the rubber, to make grooveson the plastic, to increase the wideness of the plastic, to add bulges on the plastic and to make the external surface of the plastic cylindrical. FEA of the five optimization structurewere performed, and then the results of the stress and longitudinal static stiffness wererespectively compared with the original structure.And next, the fatigue life analysis of the thrust rod was performed. First, wesummarized the common failure modes of the thrust rod and stated the fatigue life theory ofrubber. Then, we used FEA to predict the position of fatigue failure. Finally, we performedthe fatigue test to require the fatigue life of the thrust rod.At last, we compared the original structure with the optimization structure in strength,longitudinal static stiffness and fatigue life and summarized the advantages anddisadvantages of each optimization method. Finally, the best optimization structure wasproposed.The optimization method proposed in this paper can improve the service life of thethrust rod effectively, which can bring economic benefits. At the same time, the study inthis paper can also guide the forward design process of the thrust rod.