| With the development of science and technology and the rapid improvement of national economic strength,the penetration rate of agricultural mechanization in China is getting higher and higher,and the use of agricultural vehicles is becoming more and more widespread.With the increase in the use of agricultural vehicles,vehicles are also developing in the direction of large size,high speed,and comfort.Vehicle vibration and noise issues have increasingly attracted the attention of users and vehicle design and production enterprises.As for the unevenness of the road surface,the violent vibration of the vehicle body is greatly reduced by the vibration damping function of the shock absorber during the driving of the vehicle.The damper valve system structure is a key component of the damper,and plays a vital role in the damping performance of the damper.This paper takes the valve system structure of the key components of the shock absorber as the research object,and focuses on its dynamic characteristics.Analyzed the load model of the damper valve disc(external excitation force Qouter,pre-tightening force FDynamic preload,relief pressure FRelief pressure),A dynamic mathematical model of the valve system structure of key components of the shock absorber was established.Qualitative and quantitative analysis of the results obtained using numerical solutions:The relationship between vehicle speed vvehicle,pavement sine wave wavelength λ,amplitude A,damping fluid damping coefficient C and dynamic characteristics(vibration period T,amplitude wMAX,frequency f)of the damper valve system structure.It can provide references for how to reduce vibration,reduce amplitude,avoid resonance,and reduce noise when designing shock absorbers.The main research contents of this article are as follows:(1)The unevenness of the road surface(factor:road surface amplitude A,wavelengthλ)and vehicle speed vvehicle are the two main factors that cause vehicle vibration.This article idealizes the more complicated road unevenness into a mathematical expression of a sine wave with a wavelength of λ:y=h sin(x/λ).The pressure difference between the upper and lower chambers of the damper valve system structure |q1-q2|is related to the change in the volume of the upper and lower chambers,and is proportional to the acceleration d2y/dt2 of the vehicle’s ups and downs when driving on uneven roads..A mathematical model of the excited vibration force Q of the damper valve system structure was established,and the spring pretension force K1△,spring deformation force K1w,damping force C(?)and small opening of the damper valve disc were also taken into account At the time of the relief pressure FRelief pressure.a dynamic mathematical model of the damper valve system structure was finally established.(2)In this paper,the equivalent bending stiffness Dn of the multi-valve superimposed structure of the damper valve system is calculated,and it is used to calculate the natural frequency of the damper valve system structure ω.The linear and nonlinear dynamic characteristics.The natural frequency ω of the superimposed structure of the damper valve system is solved by the DQ method,so that the safe zone of the vehicle’s running speed on a certain uneven road can be determined to avoid the resonance of the damper.(3)The time domain DQ method was used to solve the time history response of the damper valve system structure under the action of the exciting force.The dynamic characteristics of the shock vibration of the shock absorber were analyzed.The numerical results were qualitatively and quantitatively analyzed from the numerical results:Relations between driving speed vvehicle,road sine wave wavelength λ,amplitude A,damping fluid damping coefficient C and vibration characteristics of the damper valve system structure such as vibration period T,amplitude wMAX,frequency f and other dynamic characteristics.In the design of the shock absorber,how to reduce the vibration,reduce the amplitude,avoid resonance,reduce noise and other issues have been beneficially explored.(4)Considering that when the damper valve disc is opened,its displacement far exceeds the linear range,and the dynamic analysis of the damper on more precise machinery or high-end vehicles must also consider the nonlinear effect of the damper.Therefore,this paper further studies the non-linear dynamic characteristics of the damper valve system structure taking geometric non-linear factors into consideratio.1/2(?)and compares it with the linear calculation results. |
