1. 研究目的与意义（文献综述）

road wreckers are also called trailers and accident rescue vehicles. it consists of a chassis, lifting device, lifting traction device, hydraulic system, electronic control system, body and toolbox. it is equipped with lifting, dragging, lifting and other devices on the basis of a dedicated cargo chassis. it has a number of functions such as lifting, dragging and lifting, and is applicable to clearing operations of highways and city roads. compared with other special vehicles, road wreckers have a relatively short history of development. they are mainly used to clear accident vehicles and eliminate road obstacles. side road wreckers are characterized by the ability to lift accidents or faulty vehicles from the side.

china's road wreckers started in the early 1990s. at that time, the social demand was small, and the style structure was mostly in the form of hanging. with the acceleration of the highway process in china, the demand for wreckers entered the outbreak period after this century. the wrecker technology has also been greatly improved, and product design techniques and manufacturing processes have also achieved breakthrough development. in the past 20 years, the wrecker industry in china has gone through the process of introducing complete vehicles, absorbing imitations, and independently researching and developing wreckers. the type and level of products have been gradually increased and improved from the original suspension type and flat-bottom type.

however, we still have a big gap compared with the advanced developed countries' wrecker technology. for example, the u.s. wreckers started earlier, advanced technology, and the product has three major characteristics. first, the variety is full-featured. from light to super heavy tonnage, there are all kinds of wreckers with different specifications and functions. second, the structure is novel and beautifully manufactured. the overall appearance is beautiful and full of creativity, and the structure is compact and nuanced. third, new materials and new technologies are widely used. for example, high-strength plastic materials are used for the body of wreckers, and aluminum-type materials are used for rolling shutter door type toolbox doors and aluminum flat plates. in terms of system monitoring, integrated control, etc., advanced electronic control technologies and equipment are also commonly used. this makes the wrecker safer and more reliable to use.

2. 研究的基本内容与方案

(1) The basic research content of this paper is as follows:
①The paper will outline the situation and research significance of light side road wreckers at home and abroad.
②According to the requirements of working conditions, the thesis will select the type of vehicle chassis structure and the overall layout.

③The paper will do some design and calculation for the road-removed wrecker's clearing mechanism.

(2) Research objectives:
The design is planned to be based on a road wrecker and to lift the accident or faulty vehicle from the side.It is equipped with a lateral lifting mechanism to achieve the purpose of eliminating obstacles and saving time.

(3) Proposed technical solutions and measures：

The choice of the wrecker chassis: As the wrecker is a special-purpose vehicle, the performance of the chassis plays a decisive role in the performance of the wrecker. So the key to choosing the chassis is to make the chassis meet the requirements of the special device. Because the light wrecker is based on ground operations, the chassis of the second type of wagon is selected as the chassis of the design wrecker.
The overall layout of the wrecker: First of all, the task of the overall arrangement is to make the special device and the chassis of the car match each other in order to obtain better basic performance and special performance of the wrecker. The side position wrecker is based on a flat wrecker, and a lifting mechanism is added to the side of the wagon to connect the power take-off to the low gear of the gearbox or the output shaft of the sub-tank to output power to the external working device. The overall arrangement parameters of the wrecker include profile dimensions, wheelbase, rear suspension and mass parameters. The dimensions of the outer dimensions are 7338×2350×2430 (mm), the wheelbase is 3800mm, the total mass is 8200kg, the trim mass is 4500kg, and the front suspension/rear suspension is 1068/2470mm.

Chassis structure selection:

Chassis performance parameters
Chassis model	EQ1080SJ9BDE	Number of axes	2
Wheelbase	3800（mm）	Front track（mm）	1570（mm）
Front passenger	3	Rear track（mm）	1530（mm）
Number of tires	6	Number of springs	6/6 5
Tire specifications	7.50-16LT 14PR，7.50R16LT 14PR
Others	When the front disc brake is selected, assembling ABS. And the model is 3550010-H01111

Chassis power parameters (engine parameters)
Engine model	Engine manufacturer	Displacement（ml）	Power（kw）
ZD30D13-4N	Dongfeng Light Engine Company Limited	2953	96
Emission Standards：	National Four
Fuel type：	Diesel

3. 研究计划与安排

Weeks 1-4: Conceptualization of the project and completion of the opening report and literature search.
Weeks 5-7: Completion of foreign language translation, data collection and sketching and calculation.
Weeks 8-12: Drawing and design calculations, compilation of design calculation instructions and organizing.
Week 13: Apply for reply and prepare it.
Week 14-15: Attend the reply.

4. 参考文献（12篇以上）

[1]郑舒. 我国道路清障车发展现状及趋势[j]. 专用汽车, 2017, (8): 48-50

[2]王锋. 中型道路清障车总体布置设计方案[j]. 中国高新技术企业, 2017, (05): 5-7

[3]关卫国. 清障车总布置设计探讨[j]. 商用汽车, 2003, (12): 51-53