【正文】 的工作性能。各機構(gòu)使用管路聯(lián)結(jié)，能夠得到緊湊合理的速度，改善了發(fā)動機的技術(shù)特性。 泵 — 馬達回路是起重機液壓系統(tǒng)的主要回路，按照泵循環(huán)方式的不同有開式回路和閉式回路兩種。 現(xiàn)在普遍使用的汽車起重機多為液壓伸縮臂汽車起重機，液壓伸縮臂一般有 2~4節(jié)，最下 (最外 )一節(jié)為基本臂，吊臂內(nèi)裝有液壓伸縮機構(gòu)控制其伸縮。回轉(zhuǎn)系統(tǒng)加轉(zhuǎn)了動態(tài)穩(wěn)定性較好的平衡閥，減少了沖擊，提高了操作精度。 關(guān)鍵詞：液壓系統(tǒng)，變幅液壓缸， 起升機構(gòu)， 雙泵分合流 Ⅰ ABSTRACT This paper focuses on the QY8 type truck crane hydraulic system, hoisting mechanism, varying hydraulic cylinder made of three parts research and design. Loop hydraulic system and the rotation speed was improved circuit design, speed control system with a more reasonable twopump open subconfluent systems, and optimize the lift to the structure, use small size, great for special transmission ratio Winch Plaary reducer, so that the hoisting mechanism more pact. Rotary switch to a dynamic stability system, plus a good balance valve, reducing the impact of increased operational accuracy. On the amplitude structure and parameters of hydraulic cylinder design, specific to the three nodes force model and analysis, amplitude stability check of hydraulic cylinder and so on. Hoisting mechanism on a preliminary design, the main casting reel made of the posite welding structure design, the use of a plete theory of the cylinder wall strength analysis. Keywords: Hydraulic System, Luffing cylinder, Hoisting mechanism, Doublepump subconfluent Ⅱ 目 錄 摘 要 ........................................................................................................... 2 ABSTRACT .................................................................................................. 3 第一章 緒論 ............................................................................................ 5 汽車起重機簡介 ................................................................................................... 5 液壓傳動應(yīng)用于汽車起重機上的優(yōu)缺點 ........................................................... 5 優(yōu)點 ............................................................................................................... 6 缺點 ............................................................................................................... 6 國內(nèi)汽車起重機行業(yè)發(fā)展現(xiàn)狀 ........................................................................... 7 汽車起重機產(chǎn)品分類 ................................................................................... 7 汽車 起重機市場的規(guī)模 ............................................................................... 8 國內(nèi)汽車起重機市場結(jié)構(gòu) ........................................................................... 8 市場競爭格局 ............................................................................................... 9 本課題來源及任務(wù)要求 ....................................................................................... 9 本課題主要研究工作 ......................................................................................... 10 第 2 章 液壓系統(tǒng)性能分析與原理設(shè)計 ................................................. 11 QY8 典型工況分析及對液壓系統(tǒng)要求 ............................................................. 11 QY8 典型工況的分析 .................................................................................. 11 對液壓系統(tǒng)要求 ......................................................................................... 11 對 QY8 液壓系統(tǒng)各主要回路的分析 ................................................................ 12 液壓系統(tǒng)類型的擬定 ......................................................................................... 17 本機液壓系統(tǒng)分析 ..................................................................................... 17 各機構(gòu)動作組合、分配及控制 ................................................................. 17 QY8 型汽車起重機液壓系統(tǒng)的工作原理總成 ................................................. 19 支腿收放回路 ............................................................................................. 20 吊臂變幅回路 ............................................................................................. 21 吊臂伸縮回路 ............................................................................................. 21 轉(zhuǎn)臺回轉(zhuǎn)回路 ............................................................................................. 22 吊重起升回路 ............................................................................................. 23 QY8 型汽車起重機液壓系統(tǒng)的工作情況表 ........................................... 23 QY8 型汽車起重機液壓系統(tǒng)的特點 ....................................................... 24 第 3 章 液壓系統(tǒng)計算 ........................................................................... 25 主要液壓元件的選擇 ......................................................................................... 25 8 噸液壓汽車起重機的主要技術(shù)參數(shù)的初定 ....................................... 25 起升馬達的計算和選擇 ........................................................................... 25 液壓泵的計算和選擇 ............................................................................... 27 Ⅲ 液壓系統(tǒng)發(fā)熱溫升計算 ..................................................................................... 28 計算液壓系統(tǒng)的發(fā)熱功率 ......................................................................... 28 計算液壓系統(tǒng)的散熱功率 ......................................................................... 29 第 4 章 變幅液壓缸設(shè)計 ....................................................................... 31 變幅液壓缸的結(jié)構(gòu)設(shè)計 ..................................................................................... 31 缸體端部連接結(jié)構(gòu) ..................................................................................... 31 活塞與活塞桿的連接方式 ......................................................................... 32 活塞桿頭部結(jié)構(gòu) ......................................................................................... 33 缸體安裝形式 ............................................................................................. 33