Bus Semi-Air Suspension Research

Under the background of slowing sales growth and declining output value of the domestic bus market,the design and development of modern bus suspension should not only meet the user's demand for vehicle comfort,but also make further requirements for enterprises tocontrolmanufacturing cost strictly,in order to face the brutal market competition.Combined with the characteristics of air suspension and leaf spring suspension,the parallel combination of two elastic elements is designed to form a leaf spring-air spring composite suspension,which not only introduces air spring to improve the elastic characteristics,but also retains the plate spring structure,making minor changes to the traditional plate spring suspension structure.This paper studies the performance of a composite suspension and analyzes the engineering problems after its application.Firstly,the paper analyzes the elastic characteristics of the air spring,and points out that the variable stiffness characteristics of the air spring meet the requirements of the ideal suspension elastic characteristics.At the same time,the advantages and disadvantages of the existing air spring suspension are analyzed,in order to introduce the characteristics of leaf spring-air spring composite suspension.Secondly,the performance characteristics of composite suspension are studied.The main evaluation indexes include body acceleration,suspension dynamic deflection and wheel dynamic load.The research methods include full analytical analysis and numerical simulation.The full analytical analysis method is used to study the three kinds of air spring states corresponding to three different loads.The numerical simulation analysis method directly introduces the air spring characteristic curve into the simulation model,which is no longer linearized at a specific load point like the first method.The research methods of "performance" of composite suspension are summarized,including linear analytical analysis and nonlinear simulation analysis.The former is suitable for the analysis of multi-load points and the latter is suitable for the analysis within the full deformation range.Aiming at the braking runout phenomenon caused by the composite suspension when the emergency brake wheel is locked,the mathematical modeling is carried out,and then the stability of the system is analyzed according to the nonlinear vibration theory,and the influence of different suspension parameters on the system stability is analyzed by numerical simulation,so as to obtain the method of restraining the braking runout.Finally,a design method of composite suspension is proposed.The design of composite suspension involves the design of air spring,leaf spring,shock absorber,transverse stabilizer and other key parts,the selection of the overall structure of suspension and the integrated assembly of suspension.Combined with the research in this paper,the design method for each key force element is given,and the design process has certain engineering application value.