| The vertical stiffness of the secondary suspension is the most sensitive parameter that affects the vertical stability of the vehicle.At present,the bogie secondary suspension used at home and abroad is characterized by linear rigidity in the vertical direction.On the one hand,the structural design has a certain spatial size,which causes the load-bearing stiffness to increase as the load increases,so as to ensure the structure after load.The deformation is within a certain range;on the other hand,in order to ensure the vertical stability of the vehicle operation,it is necessary to reduce the vertical stiffness of the suspension device to improve its vibration isolation efficiency.This will inevitably cause the contradiction of the vertical stiffness value of the suspension device.The vertical stiffness of the current bogie secondary suspension device is only designed after comprehensive consideration of the influence of the two aspects,and it cannot achieve the effect of optimizing both simultaneously.With the development of heavy-duty fast goods vehicles,the requirements for bogies will continue to increase.How to realize the integrated design of bearing and vibration-isolation of bogie secondary suspension systems will become an important issue.The main purpose of this paper is to construct a second-type suspension system with nonlinear stiffness characteristics based on the geometric nonlinear design method of SD oscillator.By adjusting the geometric parameters,the stiffness characteristics of the system are characterized by high static stiffness and low static stiffness,so that it has higher bearing capacity and vibration isolation efficiency at the same time,so as to solve the problem of vertical smoothness existing in heavy load trucks.Based on the current bogie technology and SD oscillator theory,the existing secondary suspension system model is modified and an improved rear suspension system theoretical model with nonlinear stiffness characteristics is proposed.The spatial stiffness distribution of the system is analyzed,and the conditions for quasi-zero stiffness and stability quasi-zero stiffness are given.And use the average method to analyze the vertical dynamic performance of the system.The vehicle dynamics simulation model was established,and the relationship between the three-way equivalent stiffness of the improved secondary suspension system and the vehicle operating performance was clarified through simulation analysis.Combined with the specific construction of the bogie,the parameters of the secondary suspension system are determined.Based on this,the dynamic simulation analysis of the vehicle before and after improvement of the bogie secondary suspension system was performed,and the performance differences of the snake stability,curve passageability and linear stability were compared.The conclusion shows that the vehicle’s vertical stability performance can be greatly improved under the premise of guaranteeing the same bearing capacity and other performance indicators to meet the requirements through reasonable parameter configuration.To achieve the design of the secondary suspension system bearing vibration isolation integration. |
