摘  要改革开放以来，我国的经济发展日新月异，社会建设也在大规模进行中，与此同时，起重机的使用也愈加频繁，对起重机的要求，尤其是起重能力,机动性和操作起重的半径也愈来愈高,以促进快速发展,同时,拥有国内外先进塔式和汽车起重机已成为主要的机械结构。与其他起重机比较，汽车起重机具备灵敏，移动便利，易于实现利用各种姿势提升的好处。现如今，由于液压技术飞速发展，起重机已成为每个起重机制造商发展的主要目标。69994

QY20型起重机整个设计制造过程中最重要最核心的内容是该型汽车起重机液压系统的设计。本文依据液压系统的各项技术指标对该系统进行总体方案设计，对该系统的性能结构和工作原理进行分析，初步拟定液压系统各个回路的主要元件和基本结构，按照所给液压性能参数和机构性能参数对元件进行选择计算，并通过对系统发热校核和性能的验算，满足该型号起重机所要达到的要求。

常见的汽车起重机液压系统由五个部分组成，要设计出一个完整的起重机液压系统，就必须分别对各个液压回路进行分析设计，最后再将五个回路组合在一起，便可得到完整的液压回路原理图。然后进一步计算出适合该型起重机的所有应用元器件，并通过相关参数对其进行检验校核，最终，一个完整的汽车液压起重机的液压系统就被设计出来了。

该论文有图21幅，表5个，参考文献29篇。

毕业论文关键词：汽车起重机； 液压系统； 性能参数； 支腿液压缸

QY20 Truck Crane Hydraulic System Design

Abstract In recent years, because of the constant expansion of the scale of engineering construction, lifting work quantity is becoming more and more big, the lifting capacity, operating radius and high requirements of the motor performance prompted crane is developing rapidly, at the same time, with advanced levels of the tower and crane has become the main mechanical construction.

Compared with those of other crane crane has flexible operation, mobile convenience, the advantages of easy to realize multiple position of hoisting, at the same time，it is also easy to put the drive and control of the hydraulic system into effect to improve the design. With the constant development of hydraulic technology, the crane has become the main development object of each crane manufacturers.

QY20 type crane design is the key step in the process of the type of truck crane hydraulic system design. On the performance of the system structure and working principle were analyzed, and the preliminary plan of each loop hydraulic system basic structure, main components and hydraulic performance and organization performance parameters according to the given to select element calculation, and via heat checking and calculating the performance of the system, to meet the requirements as to the type of crane. 

Common Crane hydraulic system consists of five parts, to design a complete crane hydraulic system, it must be separately for each hydraulic circuit analysis and design, then the final five circuits together, you can get the complete hydraulic circuit schematics. And further calculates the crane suitable for all application components, and its verification by the relevant test parameters, ultimately, a complete automobile hydraulic crane hydraulic system was designed out.

    The papers Figure 21, Table 5, reference 29.

Keyword: Auto crane;  The hydraulic system;  The performance parameters;  Leghydraulic cylinder 

目    录

摘要Ⅰ

Abstract-Ⅱ

目录Ⅲ

图清单-Ⅴ

表清单-VI

变量注释表-VII

1 绪论-1

1.1  起重机简介-1