Optimal Design And Analysis Of The Taper-Leaf Spring With Variable Stiffness And Closely Intermeshing For The Heavy Tractor Rear Suspension

Automobile industry is an important indicator of a national industrial development and integrated manufacturing capabilities.At present,vehicles’ ride performance and comfort, especially for heavy tractor, have become increasingly demanded.Taper-leaf spring with variable stiffness compared with the traditional multi-leaf spring or taper-leaf spring has great advantages in the above two aspects. As the ability of design and manufacturing,as well as materials research and development are continuously improving,suspension system of taper-leaf spring with variable stiffness has become the development trend of heavy tractor.In this paper,take a heavy tractor as the platform,directed at the fact that taper-leaf spring with variable stiffness is designed and produced,combined with advanced design research method at present,main spring and auxiliary spring using contact method of closely intermeshing curve,for optimization design of the rear suspension taper-leaf spring with variable stiffness.The main work includes:(1) Research the mathematical model of leaf spring, insight into the design and calculation method of trapezoidal taper-leaf spring,then the original mathematical model of the rear suspension taper-leaf spring is established and the taper-leaf spring stiffness,strength and other calculation methods is studied,and then analysis the structure performance of the original model.(2) To meet the premise of the design requirements of rear suspension,both superior and subordinate using the taper-leaf spring with variable stiffness and closely intermeshing,optimization design toolbox for structural parameters is done on the application of MATLAB to determine the appropriate structure design parameters of the main spring and auxiliary spring between superior and subordinate;Then the structure properties between the original structure of rear suspension’s main spring and auxiliary spring between superior and subordinate and the optimal one were compared.discussed how to determine the main spring and auxiliary spring between superior and subordinate K point location and the closely intermeshing curve of taper-leaf spring with variable stiffness under free state.(3) Considering the large deformation and contact between the leaf spring,and treat with the elements’ attributes properly to figure out the nonlinear contact condition of the leaf spring,the finite element model of rear suspension’s taper-leaf spring with variable stiffness and closely intermeshing is established by using Hyper Mesh module of ANSYS based on nonlinear finite element method.The stress and strain distribution of the leaf spring was analyzed under three conditions of full load, dynamic load and clamping.Results showed that the leaf spring of optimization design meet the design requirements,a high precision of the model is set up.(4) Based on traditional multi-leaf spring and leaf spring with variable stiffness simple beam model,intuitively reflect the stress and offset frequency differences between traditional multi-leaf spring and leaf spring with variable stiffness in MATLAB,contrast and analysis the suitable conditions of the leaf spring with variable stiffness.By using the methods of theoretic analysis and knowledge based on experience to solve practical engineering problems, combined with production practice closely,In the meantime,delivers a set of optimizing design scheme of rear suspension’s taper-leaf spring with variable stiffness and closely intermeshing,then contrast and analysis the pros and cons of leaf spring with variable stiffness and traditional multi-leaf spring,for rear suspension’s taper-leaf spring of engineering design has a certain guiding significance.