Research On Mechanism And Design Of Automobile Hydraulic Shock Absorber Rattling Noise

The automobile suspension system has a very important influence on the stability, ride comfort and safety of the vehicle. Hydraulic shock absorber is one of the important parts of the automobile suspension system, the quality of the hydraulic shock absorber will directly affect the quality of the car’s condition. Because of its complex structure and more parts, the automobile hydraulic shock absorber are more prone to failure. Among the many failures, the shock absorber Rattling noise account for a large proportion. Therefore, the shock absorber mechanism Rattling produce abnormal noise and anti-abnormal sound design has important significance.This paper based on the actual engineering project in the shock absorber Rattling abnormal sound problem. Established the fault tree of Rattling abnormal noise. By means of CAE simulation established a reliable simulation model of the shock absorber, and the parameter sensitivity analysis and robust optimization design of main parameters are carried out. Specific work is as follows:(1) According to the working principle of the shock absorber and the associated physical model, using AMESIM to establish a one-dimensional simulation model of the shock absorber. And the simulation results of dynamometer characteristics, velocity curve and rod end vibration acceleration are compared with the experimental results. The confidence of the simulation model is verified, and the simulation model can be satisfied with the requirement of engineering practice. For the subsequent conduct of the shock absorber Rattling abnormal noise laid a solid foundation.(2) By means of implementation damper bench noise and vibration testing, signal analysis and statistical analysis, the vibration acceleration of the rod end of the shock absorber and the non-abnormal sound shock absorber are compared and analyzed. And an internal shock absorber components related to the modal simulation, the results can be used to explain the mechanism of the impact of the shock absorber.(3) Analysis the relationship between Rattling of shock absorber and vibration, and internal components of the vibration absorber. The failure mechanism of Rattling abnormal noise is expounded. The fault tree of the shock absorber Rattling is established, and the structural parameters which are closely related to the Rattling of the shock absorber are defined.(4) According to the fault tree of the shock absorber Rattling noise, select 19 design structural parameters analysis and calculation of closely associated with of the shock absorber Rattling noise by using a one-dimensional simulation model of shock absorber. Calculated the size of each factor sensitivity, and the corresponding Pareto diagram of each factor is also obtained. For eleven factors greater sensitivity, select multiple values within the scope of their possible values are simulated. And make the objective function with the change of the factors of the curve, analysis of the design of structural parameters on the shock absorber rod end vibration acceleration.(5) The robust optimization design of the factors which are sensitive to the vibration acceleration of the rod end of the shock absorber. For design variables and noise variables using two different classification, by using the method of Robust Design Method Based on the loss model carried out the robust optimization design simulation. The optimal value of the related design variables is obtained, so that the sensitivity of the vibration damper to the fluctuation of the noise variable is decreased under the same operating conditions. At the same time, the design of structural parameters in two different classifications optimized using the Monte Carlo method for validation. On the basis of the optimal design variables, separately carried on the tolerance design and calculation, so that it can under the most economic conditions still meet the design requirements of the quality characteristics of the shock absorber.There are several innovative points in this topic:(1) The fault tree of the shock absorber Rattling abnormal noise is established, easily lead to abnormal sound damper Rattling events decomposition, which is of great value in engineering application.(2) Will Lu Bang (sound) design was applied to study the shock absorber Rattling noise. The parameters closely related to the influence of the shock absorbers Rattling noise are designed and tolerance robust design optimization. The tolerance ability of the vibration damper to the manufacturing and using process is enhanced.