Study On Structure Optimization And Dynamic Performance Of Hydraulic Shock Absorber For High Speed Train

Nowadays,Chinese rail vehicles have entered a brand-new stage that is rapidly developing at a high speed.Correspondingly,passengers put forward more stringent requirements on train safety,stability and comfort.The hydraulic shock absorber is the key component of the rail vehicle suspension system,which plays a key role in the absorption and mitigation of the excitation disturbance,structural vibration and snake shape motion caused by track irregularity.The important influence factor of the damping characteristics of the hydraulic shock absorber is its structural parameters,and its change will have a great influence on the dynamic performance indicators such as the stability of the vehicle body,the curve passability and the critical speed.Currently,most of our high speed trains are mainly equipped with hydraulic shock absorbers,and the piston is the key component of the hydraulic shock absorber,which plays a decisive role in the performance of the whole hydraulic shock absorber.To achieve high-speed train key parts localization,the combination of high-speed train on the hydraulic shock absorber performance requirements and operation environment,based on the working principle of double cylinder hydraulic shock absorber and the basic structure,using hydraulic simulation software MSC.Easy5,according to the actual type CRH380 B emu shock absorber parameters,hydraulic control model of shock absorber is established.The accuracy of the hydraulic control model was verified by comparing the simulation test with the actual test data,and the feasibility of the innovative design of the hydraulic shock absorber piston was analyzed.Based on the comparatively validated MSC.Easy5 hydraulic control model,the second-order transverse hydraulic shock absorber is taken as the research object.The main structural parameters of the hydraulic damper,such as the damping aperture of the restoring valve,the circulating valve and the stiffness of the compensation valve,are taken.When the hydraulic shock absorber component fails,the damping characteristics are also affected.To make the hydraulic damper give full play to its own function and get the best matching relationship between the hydraulic shock absorber and the vehicle,not only the damping characteristic of the hydraulic shock absorber should be studied,but the influence of the characteristic parameters of the damper on the dynamic performance of the train should be further analyzed.Based on the relevant theories of vehicle dynamics,according to the actual parameters of the train,the dynamic simulation model SIMPACK was used to establish the dynamic model of the train.The accuracy of the model was verified by comparative analysis.Taking the longitudinal damper in the workshop as the research object,the influence of the vertical damper installed on the dynamic performance of the high-speed EMU was analyzed.The results show that the shock absorber hydraulic control model based on the MSC.Easy5 simulation software is accurate and reliable,and can accurately predict the damping characteristics of the hydraulic shock absorber in the initial design stage.The new piston structure with innovative design meets the design requirements and work requirements.The damping force values tend to be standard 1500 N,and the asymmetry rate is less than 10%.To change the bore diameter of the piston,the maximum change of damping occurs in the compression stroke,which increased by 1631 N,and the change amplitude was about 109%.The aperture of the piston recovery valve and the compression valve affects the damping force of the recovery and compression stroke respectively.The maximum change of the damping force is 312 N,the maximum change range is about 22%.The unsuitable spring stiffness of the compensation valve is one of the main factors that cause the deformity of the indicator diagram curve.The change of characteristic parameters of hydraulic shock absorber has great influence on dynamic performance.The installation of a reasonable inter-vehicle longitudinal shock absorber has a certain influence on the lateral dynamics of the vehicle body,such as the lateral acceleration of the vehicle body and the lateral stability index,among which the low-frequency shaking head movement of 1-3 Hz is obviously inhibited.The research content of this paper promotes the further acceleration of the localization of hydraulic shock absorbers and key components,and provides technical basis and theoretical reference for the realization of the performance design,debugging and actual production of hydraulic shock absorbers.