Research And Implementation Of Leaf Spring On MPV Micro Car Weight Reduction

Leaf spring which is a part of the automobile suspension is running up and down as the excitation of road surface in the running process of the vehicle. The leaf spring can buffer shock and reduce vibration, and its quality plays an important role in the vehicle stability and safety. Nowadays, weight reduction, energy saving and environmental protection of the vehicle is an important aspect of modern automobile development, including leaf spring weight reduction, which can reduce fuel consumption and steel consumption. The leaf spring weight reduction not only contains mass reduction, but also the actual use condition satisfaction, the service life and vehicle comfort improvement and the cost reduction, so the weight reduction research is not only the requirement of our country, but also the aim of enterprises. Therefore, it has important practical significance for the research of the leaf spring weight reduction.The weight reduction of leaf spring on a rear suspension of a MPV vehicle is considered further in this paper. In the using condition of 5 pieces of original leaf spring, the formula of taper leaf spring stiffness is derived according to the deformation theory of unit load method and beam deformation, the mass optimization mathematical model of variable cross-section leaf spring is established, and optimal solution is solved in the condition of stress,stiffness and length satisfaction, and then stiffness value and stress distribution along the length is solved from the stiffness and stress formula; the static finite element model is established based on the modern contact theory, the stress and stiffness is analyzed and then compared with the theoretical solution, the conclusion shows that CAE analysis and solution of the theoretical model is in the range of error; fatigue life optimization spring is analyzed, the value is 120,000 times in the enterprise standard requirements, and shows that meet the use requirements; dynamic hysteresis characteristics of leaf spring in continuous loading and unloading is considered, the conclusion is that the influence of friction between spring and spring material lead to the inconsistency of loading and unloading curves; dynamic theory model of leaf spring is established, considering the friction damping effects on the vibration characteristic of leaf spring, stiffness of the leaf spring is set as a variable, it shows that the vibration can reduce in the given stiffness range; for the trial of spring, and the samples of the leaf spring are made, the stiffness and fatigue life are tested in different number of silencing shim, and compared with the theory and CAE simulation, the result shows the theoretical solution and simulation results are accurate; finally a sample is installed in the vehicle, so the road test can be done, the results are consistent with the actual vehicle service life, the mass of the optimization leaf spring reduced 25.47% compared with the original leaf spring.