Research On Adjustment And Influence Of Suspension And Steering Hard Point Of A Vehicle

Steering wheel torque not only indicates whether the steering system design is reasonable,but also an important indicator of vehicle handling stability evaluation.In this paper,the steering wheel torque and its fluctuation are too large in the process of R&D.The steering wheel torque and its causes and influencing factors are analyzed,and the ideas and methods of optimization steering wheel torque and its fluctuation are obtained.The main research contents are as follows:(1)The three factors influencing the steering wheel torque are analyzed: Tire static steering torque,gravity generated by the positive torque and steering system friction torque of the steering system are established.The theoretical calculation model of steering moment of the steering wheel is established,and the steering wheel torque is calculated at 30N·m.at the same time,according to the relevant test standards,real car test to get the steering wheel torque of 35N·m or so.Neither of these meets the national standard,and the torque fluctuation is also large,so the development of the steering system should be optimized.(2)In order to solve the problem of steering wheel torque fluctuation,the fundamental reason of steering wheel torque fluctuation is the existence of universal joint in steering system,and the torque fluctuation of steering system is independent of the design hard point.According to theoretical calculation and The simulation results show that the steering wheel torque fluctuates is minimal when the phase angle and the plane angle satisfy both and 0° or 180°.When the torque fluctuation is within 10%,the phase angle of the universal joint can be in the range of ± 30 ° Internal adjustment,which provides a reference for the arrangement of the steering system(3)Through the analysis of the influencing factors of the steering wheel torque,it is found that the Kingpin inclination angle and the steering angle ratio have a greater influence on the static steering torque,and the steering angle ratio depends on the total number of turns and the length of the steering arm Through the Adams / insight,the key hard points of the steering system are analyzed,and the main hard-point coordinates which affect the Kingpin inclination angle and the length of the steering arm are obtained.Using the response surface method to optimize the key hard-point coordinates,the steering wheel steering torque is 22N·m,compared with 35N·m before the reduction of 37.14%,to meet the design requirements of R&D.(4)Through the ADAMS software,the model of the steering system,the front suspension system and the stabilizer bar system before and after.the hard spot optimization is established.It is concluded that the K&C characteristic of the rear suspension is better than the optimized K&C characteristic of the front suspension.