Research On The Vertical Rigidity Of Double Tube Air Spring With Additional Air Chamber

The suspension system plays an important role in the vehicle dynamics and safety performance.The design of the suspension system needs to consider various characteristics such as ride comfort,suspension travel and braking and driving performance.The unique advantage of the air suspension system is that it can meet the various requirements of suspension design,and therefore has attracted the attention of many scholars and engineers at home and abroad.In this paper,we investigate the dynamic and static stiffness characteristics of the air spring system,which is the core component of the air suspension system.To address the problems of the single-tube air spring system,a structural improvement is proposed,i.e.,a double-tube air spring system is proposed to improve the vertical stiffness characteristics of the air spring system,and the advantages of the double-tube air spring system are verified through tests.The main work of the thesis is as follows:.(1)A test system with a single air spring,a single-tube air spring and a double-tube air spring was designed.A test protocol for the static and dynamic stiffness of a double-tube gas spring system with an additional gas chamber is proposed.By comparing the dynamic stiffness characteristics of the single-tube and double-tube gas spring systems,it is concluded that the double-tube gas spring system can have lower dynamic stiffness characteristics and smaller dynamic stiffness fluctuations.(2)Establish a finite element model of the main air chamber of the air spring and analyze the nonlinear characteristics of the main air chamber of the air spring.The module is used to analyze the effects of initial air pressure,cord angle,cord spacing and number of cord layers on the load-bearing performance of the air spring.(3)The dynamics model of the double-tube air spring is established,and the expression of the dynamic stiffness is derived.And the dynamic stiffness of the double-tube air spring system is numerically simulated by Matlab/Simulink.(4)Based on CFD theory,the internal flow fields of the single-tube air spring system and the double-tube air spring system are simulated in three dimensions by using Fluent software to analyze the internal flow field distribution,flow phenomena and laws of the system.The effect of the throttle tube with different parameters on the dynamic stiffness characteristics of the air spring system is illustrated in detail by the magnitude of the gas flow between the main chamber and the additional chamber within one sinusoidal excitation period..In this paper,an exploratory study on the dynamic characteristics of a double-tube air spring with additional air chambers is carried out,which provides a certain reference basis for further research on air suspension in the future.