1摘 要汽車起重機式工程機械產品中重要組成部分，它由于機動性好而被廣泛應用于礦山、建筑、港口、油田等領域。主要由變幅機構、伸縮機構、起升機構、回轉機構、支腿機構組成。本文講述了 QY-20 汽車起重機液壓系統(tǒng)的設計。首先，通過對汽車起重機總體構成及工作原理進行分析，在此分析基礎上提出了提液壓系統(tǒng)各功能回路的設計方案，并把各回路組合后得出了液壓系統(tǒng)原理圖；接著，設計并選擇了液壓系統(tǒng)各液壓元件并進行了相應計算；然后，對主要執(zhí)行機構-液壓缸進行了設計與強度校核；最后，通過 AutoCAD 制圖軟件繪制了本 QY-20 汽車起重機液壓系統(tǒng)原理圖的非標零件裝配圖及主要零件圖。通過本次設計，鞏固了大學所學專業(yè)知識，如：液壓與氣動傳動、機械原理、機械設計、材料力學、公差與互換性理論、機械制圖等；掌握了起重機械產品的設計方法并能夠熟練使用 AutoCAD 制圖軟件，對今后的工作于生活具有極大意義。關鍵字：起重機，起升，支腿，變幅，回轉2AbstractAs an important part of automobile crane engineering machinery products, it is widely used in mining, construction, port, oil field and other fields because of its good maneuverability. Mainly consists of variable amplitude mechanism, telescopic mechanism, lifting mechanism, rotating mechanism and supporting leg mechanism.This paper describes the design of hydraulic system of QY-20 truck crane. First of all, based on truck crane overall composition and working principle analysis, this analysis based on the proposed design scheme of hydraulic system and the function of the loop and to each circuit combination obtains the principle diagram of hydraulic system; then, design and selection of hydraulic system and the hydraulic pressure component and the corresponding calculation; then, on the main actuator hydraulic cylinders were design and strength check. Finally, through the AutoCAD drawing software drawn the QY-20 truck crane hydraulic system principle diagram of non-standard parts assembly drawing and main parts figure.Through the design, the consolidation of the University of the professional knowledge, such as: hydraulic and gas dynamic transmission, mechanical principles, mechanical design, mechanics of materials, tolerance and interchangeability theories, mechanical drawing; master the design method of hoisting machinery products and be able to skillfully use AutoCAD drawing software, for future work in life is of great significance.Key words: Crane, Lifting, Supporting legs, Amplitude, Rotation3目 錄摘 要 ...........................................................................................................................................IAbstract.....................................................................................................................................II第 1 章 緒論...............................................................................................................................11.1 研究背景及意義...........................................................................................................11.2 國內外汽車起重機發(fā)展現狀.......................................................................................11.2.1 國內發(fā)展現狀......................................................................................................11.2.2 國外發(fā)展現狀......................................................................................................21.3 汽車起重機的類型........................................................................................................21.4 汽車起重機對液壓系統(tǒng)的要求....................................................................................31.5 主要內容........................................................................................................................3第 2 章 總體分析.......................................................................................................................52.1 設計要求........................................................................................................................52.1.1 功能要求..............................................................................................................52.1.2 主要技術參數要求..............................................................................................52.2 結構及功能分析............................................................................................................52.3 工況分析........................................................................................................................72.3.1 運動分析..............................................................................................................72.3.2 動力分析..............................................................................................................82.3.3 負載分析..............................................................................................................9第 3 章 液壓系統(tǒng)設計.............................................................................................................103.1 額定壓力的確定..........................................................................................................103.2 基本回路設計..............................................................................................................103.2.1 支腿機構回路的設計........................................................................................103.2.2 起升機構回路的設計........................................................................................113.2.3 變幅機構回路的設計........................................................................................113.2.4 伸縮機構回路的設計........................................................................................123.2.5 回轉機構回路的設計........................................................................................123.3 液壓系統(tǒng)原理圖..........................................................................................................13第 4 章 液壓元件的設計與選擇.............................................................................................144.1 液壓馬達和液壓泵的選擇.........................................................................................1444.1.1 卷揚馬達的選擇................................................................................................144.1.2 回轉馬達的選擇................................................................................................144.1.3 泵的選擇............................................................................................................154.2 液壓閥的選擇..............................................................................................................164.3 液壓輔助元件選擇......................................................................................................174.3.1 液壓油的選擇....................................................................................................174.3.2 濾油器的選擇....................................................................................................174.3.3 壓力表的選擇....................................................................................................174.3.4 閥類元件的選擇................................................................................................174.4 液壓油箱的設計..........................................................................................................184.5 液壓油管設計..............................................................................................................194.5.1 油管通徑的計算................................................................................................194.5.2 壁厚的計算........................................................................................................204.6 液壓系統(tǒng)的驗算..........................................................................................................214.6.1 壓力損失的驗算...............................................................................................214.6.2 發(fā)熱溫升的驗算................................................................................................22第 5 章 液壓缸的設計.............................................................................................................245.1 支腿液壓缸的設計......................................................................................................245.1.1 支腿垂直液壓缸................................................................................................245.1.2 支腿水平液壓缸................................................................................................275.2 變幅液壓缸的計算......................................................................................................285.3 伸縮液壓缸的計算......................................................................................................29總 結.........................................................................................................................................31參考文獻...................................................................................................................................32致 謝.........................................................................................................................................33