With the growth of China's economy, China's automobile industryhas developed rapidly. Its industrial output value accounts for 4.5% of thecountry's total industrial output value, accounting for 1.46% of the nationalGDP. China's auto market is currently the world's largest single-car market,with annual production and sales accounting for 26.44% and 26.62% of world autoproduction and sales respectively. Among them, small cars occupy a large marketshare in the civilian sector, and the development and design of such cars is ofgreat significance. The theme of this design is the front suspension design ofDongfeng Qichen D601.6L sedan.

Suspension is a force transmission device between the frame andthe axle. It is responsible for transmitting the vertical reaction force, thelongitudinal reaction force and the lateral reaction force acting on the wheelon the wheel and the torque caused by these forces to the frame or the body.Its structure plays a decisive role in the steering stability and smoothness ofthe car, and is a part that cannot be ignored in the process of developing anddesigning a car. In order to mitigate the impact, elastic components must beinstalled in the suspension to maintain the elastic connection between theframe or the body and the axle or the wheel; in order to attenuate thevibration generated by the impact of the elastic system, the suspension isrequired to have a vibration damping function. A damper shall be provided inthe suspension; in order to make the trajectory of the wheel meet certainrequirements to avoid adversely affecting certain driving performance of thecar, some of the force transmitting members in the suspension are alsoresponsible for making the wheel The task of the trajectory relative to theframe or body beating, ie the guiding mechanism.

There are currently many forms of suspension structures that areused in automobiles. Among them, for the front suspension of a small passengercar, the McPherson independent suspension is used more and the technology is moremature. The MacPherson Suspension, also known as the Sliding Rod LinkSuspension, consists of a sliding column and a yaw arm. It is an improvedversion of the candle suspension. The yaw arm is added to improve the force ofthe sliding column. It is currently widely used in the front suspension offront-mounted front-drive cars.

At present, the research on car suspension mainly focus on thefollowing points:

1.1. Effect of Suspension System on NVH Characteristics ofVehicles

NVH is the noise, vibration and vibration of the car. As atransmission medium for the movement between the vehicle and the ground, thesuspension system has a significant influence on the NVH characteristics of thevehicle. The main sources of vibration and noise transmitted by the suspensionare road surface irregularities and tire and brake unevenness. Such vibrationand noise sources are not a single resonant signal, but a wide frequency bandof vibration and noise signals. From the perspective of the vehicle NVHproblem, the suspension system is a transmitter of vibration and noise. Thesuspension system NVH problem mainly studies how to reduce the vibrationtransmitted by its mechanism and the noise transmitted by its truss structure.