Hard Points Matching And Analysis Of Unsymmetrical Taper Leaf Spring Front Suspension For Truck

The performance of the front leaf spring suspension system is directly related to the riding comfort and handling stability of the truck.The use of taper leaf spring for the front suspension of the truck can not only reduce the weight of the suspension system,but also improve the riding comfort of the whole vehicle under the premise of ensuring the bearing capacity of the suspension system.Without changing the structure of the leaf spring,the friction between the leaves will directly affect the stiffness characteristics of the front suspension system.Besides,the hard point layout of the front suspension system of the leaf spring has great influence on the change characteristics of the front wheel alignment parameters,thus affecting the handling and stability of the vehicle.From the development trend of foreign truck in recent years,it can be seen that the application of asymmetric taper leaf spring is becoming more and more common.However,the asymmetric leaf spring has not been deeply studied in China.Researches show that compared with the common taper leaf spring,the weight of this kind of asymmetrical leaf spring is lighter,thus reducing the total weight of the front suspension system.What's more,this leaf spring can also improve the utilization of materials.It is significant to apply this leaf spring to domestic trucks.Aiming at matching between the asymmetrical taper leaf spring and the domestic truck,this paper bases on the project of high tech industry in Shanxi Province--engineering special truck development.Under the premise of ensuring the handling stability and improving the riding comfort of the whole truck,the finite element method is used to analyze the stiffness characteristics of the asymmetric taper leaf spring.Besides,the analysis and comparison of this type of leaf spring front suspension and the origin leaf spring front suspension are carried out by the multi-body dynamics method,and the hard point parameters of the new leaf spring front suspension system are optimized.In this paper,a finite element model of the asymmetrical taper leaf spring is established,and credibility of the model are verified by stiffness test.The stiffness characteristics of asymmetric taper leaf spring under different friction coefficients are analyzed by ABAQUS.In this paper,the indirect discrete beam method is used to establish the multi-body dynamic model of discrete beam of the asymmetrical taper leaf spring.The rigid flexible coupling multi-body dynamic vehicle model,including the front suspension of the leaf spring and the flexible body frame,is established.The riding comfort simulation of the whole vehicle model with the original leaf spring and the asymmetrical taper leaf spring is compared and analyzed.By comparing the amplitude of the power spectral density curve of the vertical acceleration in the front suspension position of the frame,it shows that the new leaf spring has the advantage of improving the riding comfort of whole vehicle.In this paper,the parallel wheel travel simulation analysis is carried out on the motion characteristics of the front suspension of the leaf spring by the suspension test bench of ADAMS/Car.The influence of front wheel suspension on the change characteristics of front wheel alignment parameters is analyzed when the front wheel jumps.According to the results,the toe angle and the caster angle are selected as the optimization objectives.A preliminary selection of hard points of front suspension is carried out,and sensitivity analysis of them is carried out.The ADAMS/ Insight module is used to optimize the five hard point coordinates of the most influential factors,and the matching between the leaf spring and the front suspension is improved from the handling and stability.