1. 研究目的与意义（文献综述）

1. purpose and significance (including analysis of current research situation at home and abroad)

automobile suspension is the general name of all the connecting devices between the frame (or the bearing body) and the axle (or wheel). it is an important part to ensure the normal running of the vehicle. it consists of three parts: spring, shock absorber and guide mechanism ^[1]. the maximum total mass of medium-sized truck is 6.0t lt; ga ≤ 14 t according to the maximum total mass of (ga) set at the time of operation of highway. the main domestic manufacturers of light and medium-sized trucks are: dongfeng, chongqing lifan, zhejiang feidie, chengdu dayun, heavy automobile, jianghuai, qingling, beiqi futian and so on. at present, the suspension of domestic medium-sized trucks is mainly non-independent suspension. suspension elastic elements are generally leaf springs. because it acts as a guiding mechanism, the suspension system is greatly simplified ^[2]. this suspension is widely used in front and rear suspension of trucks. in the middle of it, a u-bolt is used to fasten the leaf spring to the bridge.

the car model designed in this design is jianghuai gerfa k6l medium card, k6 medium card as jianghuai gerfa's 2015 masterpiece, in the appearance, power, safety and other aspects of the brand-new upgrade. the main task of suspension is to deliver the forces and moments between the wheel and the frame (or body); to ease the impact load transmitted to the frame (or body) of the road surface; to attenuate the vibration of the carrying system; to ensure the ride comfort of the car; and to ensure that the wheels have ideal motion characteristics when the road surface is uneven and the load changes; to ensure the handling and stability of the car, so that the car can achieve high-speed driving capacity. the choice of numbers will affect the dynamic performance of the vehicle, which is mainly reflected in the three aspects of vehicle performance: ride comfort, handling stability and comfort. therefore, in the design of a vehicle model, we should pay special attention to the structure selection and parameter setting of automobile suspension. choosing a suitable suspension for the car can not only guarantee the performance of the car, but also reduces the difficulty of research and development and saves the development cost. the non-independent suspension has the advantages of simple structure, low cost, high strength, easy maintenance and small change of front wheel positioning. however, due to its poor comfort and handling stability, and the cab of the truck which is arranged on the front suspension, it is particularly important to design and optimize parameters such as suspension size, which is of great significance to the experience of the truck driver. the design and optimization of parameters such as "inch" is particularly important to the experience of truck drivers. the design chooses the front suspension form composed of leaf spring and cylinder shock absorber, selects the vehicle type to design the front suspension reasonably, makes the suspension match the truck reasonably, and provides better ride, maneuverability, comfort and enough safety, makes the van run normally and drive comfortably. therefore, this design will provide some advice to freight cars and manufacturers, and it will also be helpful to their own research and study.

2. 研究的基本内容与方案

2. research on the basic content and technical scheme

2.1 basic contents

1. structural selection (structural form analysis and scheme selection) of the front suspension of the card in jianghuai gelfa k6l.

3. 研究计划与安排

3 schedule

4. 参考文献（12篇以上）

4. references

[1] wang wangyu, zhang jianwen. automobile design [m]. mechanical industry press: beijing, 2004.

[2] chen jiarui. automobile construction book 2 [m]. people's communications press: beijing, 2001.