【正文】 2 0 .2 0 .24 0 3 5 3 5 8 01 4 2 3 .0 2 8 .0 40 .1 5 0 .1 53 5 3 5 4 .8 9? ? ? ? ? ? ? ?? ? ? ? ? ? ? ?? ? ? ? ? ? ? ?? ? ? ? ? ? ? ?? ? ? ???? ? ? ?? ? ? ? ＝ 由此看出各種閥同樣滿足使用要求。為此，必須對(duì)系統(tǒng)進(jìn)行發(fā)熱和溫升計(jì)算，以便對(duì)系統(tǒng)溫升進(jìn)行控制。 將數(shù)值代入公式（ 55）得： H＝ ? ? 10 14 10 60 1 ? ? ? ? ＝ 1264w 表 51 各種機(jī)械允許油溫 畢業(yè)設(shè)計(jì)（論文） 22 液壓設(shè)備類型 正常工作溫度 /C 最高允許溫度 /C 數(shù)控機(jī)床 30～ 50 55～ 70 一般機(jī)床 30～ 55 55～ 70 機(jī)車車輛 40～ 60 70～ 80 船舶 30～ 60 80～ 90 冶金機(jī)械、液壓機(jī) 407～ 0 60～ 90 工程機(jī)械、礦山機(jī)械 50～ 80 70～ 90 液壓系統(tǒng)中產(chǎn)生的熱量，由系統(tǒng)中各個(gè)散熱面散發(fā)至空氣中，其中油箱是主要散熱面。當(dāng)只考慮油箱散熱時(shí)，其散熱量 0H 可按下式計(jì)算： 0H ＝ KA?? （ 5－ 6） 式中 K—— 散熱系數(shù)（ /W mC ），計(jì)算時(shí)可選用推薦值：通風(fēng)很差 K＝ 8；通風(fēng)良好 K＝ 14－ 20；風(fēng)扇冷卻時(shí)， K＝ 20－ 25；用循環(huán)水冷卻時(shí)， K＝ 110－ 175； A—— 油箱散熱面積； ?? —— 系統(tǒng)溫升。 取散熱系數(shù) K=15，將數(shù)值代入公式（ 57）得： 畢業(yè)設(shè)計(jì)（論文） 23 ?? ＝? ?2312641 5 0 .0 6 5 8 4?? ＝ 此溫升超過了許用范圍， ?? ＝ 30C － 50 C ，增大油箱面積，取 V＝ 814＝ 112L，并且取系數(shù) K=20Wm C ，重新帶入數(shù)值計(jì)算得： ?? ＝3 2126420 112?? ＝ 所以滿足了許用溫升要求。 畢業(yè)設(shè)計(jì)（論文） 24 6 結(jié)論 在本次關(guān)于數(shù)控銑床兩工位夾緊裝置液壓系統(tǒng)的畢業(yè)設(shè)計(jì)中，我通過查閱現(xiàn)有資料，應(yīng)用液壓傳動(dòng)的一般原理及液壓系統(tǒng)的設(shè)計(jì)原理，進(jìn)行了液壓系統(tǒng)的功能原理設(shè)計(jì)、執(zhí)行元件的選擇、閥類元件的選型、集成塊設(shè)計(jì)、密封及液壓油的選擇等工作。 并在滿足原有要求的情況下實(shí)現(xiàn)重量輕、體積小、成本低、效率高、結(jié)構(gòu)簡單、使用維護(hù)方便等的要求。在今后的工作學(xué)習(xí)中我會(huì)更加詳盡的學(xué)習(xí)，提高設(shè)計(jì)的科學(xué)性和效率。 畢業(yè)設(shè)計(jì)（論文） 25 致謝 本設(shè)計(jì)是在李實(shí)老師的悉心指導(dǎo)和嚴(yán)格要求下完成的。老師廣博的專業(yè)學(xué)識(shí)、嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度以及執(zhí)著的事業(yè)追求使我受益匪淺，他嚴(yán)緊的科學(xué)作風(fēng)和實(shí)事求是的科學(xué)態(tài)度給我留下了深刻的印象。 畢業(yè)設(shè)計(jì)（論文） 26 參考文獻(xiàn) [1] 張利平 .液壓氣動(dòng)系統(tǒng)設(shè)計(jì)手冊(cè) [M].北京：機(jī)械工業(yè)出版社， 1997. [2] 張利平 .液壓站設(shè)計(jì) [M].河北科技大學(xué)教材， 1999. [3] 張利平 .現(xiàn)代機(jī)床液壓站設(shè)計(jì)的結(jié)構(gòu)選型 [M]. 制造技術(shù)與機(jī)床， 1999，（ 10） . [4] 宋學(xué)義 .袖珍液壓氣動(dòng)手冊(cè) [M].北京： 機(jī)械工業(yè)出版社， 1995. [5] 路甬祥 .液壓氣動(dòng)技術(shù)手冊(cè) [M].北京： 機(jī)械工業(yè)出版社， 2020. [6] 楊培元 .簡明液壓系統(tǒng)設(shè)計(jì)手冊(cè) [M].北京： 機(jī)械工業(yè)出版社， 1994. [7] 陳松楷 .機(jī)床液壓系統(tǒng)設(shè)計(jì)手冊(cè) [M].廣州： 廣東高教出版社， 1993. [8] 章宏甲 .液壓傳動(dòng) [M].北京： 機(jī)械工業(yè)出版社， 1993. [9] 官忠范 .液壓系統(tǒng)設(shè)計(jì) [M].調(diào)節(jié)失誤實(shí)例分析 .北京：機(jī)械工業(yè)出版社， 1995. [10] 曾祥榮 .液壓噪聲控制 [M].哈爾濱：哈爾濱工業(yè)大學(xué)出版社， 1998. [11] 陳 愈 .液壓閥 [M].北京 :中國鐵道出版社， 1982. [12] 蔣志勤 .機(jī)床液壓傳動(dòng)教程 [M].徐州：中國礦業(yè)大學(xué)出版社， 1988. [13] 蔡春源 .新編機(jī)械設(shè)計(jì)手冊(cè) [M].沈陽：遼寧科學(xué)技術(shù)出版社， 1993. [14] 張利平，劉青社 .現(xiàn)代液壓機(jī)開發(fā)中的液壓系統(tǒng)設(shè)計(jì) [M] . 鍛壓機(jī)械， 2020. [15] 張利平 .液壓系統(tǒng)設(shè)計(jì)壓力的最佳化 [J].MM機(jī)械技術(shù)雜志（臺(tái)灣）， 2020. [16] 張利平 .近代液壓技術(shù)的幾個(gè)重要發(fā)展方向 [J].機(jī)械制造雜志， 2020， 8 月號(hào)（第 15卷第三期） . [17] Zhang Liping, Li Yingbo, Zhang Xiumin. Application Studies On Hydraulics amp。 Technological Literature Publishers, 1995. [18] Schneider R T. Don’t Fet to Congsider Accumulators. Hydraulics amp。 Pneumatics, Nov, 2020. [20] Anthon Esposito. Fluid Power With Applications. New Jersey: Prent iceHall,1980. [21] Northman Co, Ltd New Products Guide. 畢業(yè)設(shè)計(jì)（論文） 27 CONTROL OF MOBILE HYDRAULIC CRANES Marc E. M220。de 101 DK9220 Aalb. Denmark Email: mmuniet. auc. dk The goal of the thesis described in this paper is to improve the control of mobile hydraulic cranes. The thesis is split into five parts: a requirements analysis, an analysis of the current systems and their problems, an analysis of different possibiilities for system topologies, development of a new control system for the near future based on electrohydraulic separate meter in / separate meter out valves, and finally an analysis of more advanced and plex solutions which can be applied in the more distant future. The work of the thesis will be done in cooperation with industry so the thesis will have more of an industrial focus than a purely theoretical focus. Key words: Mobile Hydraulic Cranes, Control strategies, Separate Meterin/Separate Meterout. 1 INTRODUCTION The goal of the thesis described in this paper is to improve the control of mobile hydraulic cranes. A mobile hydraulic crane can be thought of as a large flexible mechanical structure which is moved by some sort of control system, The control system takes its input from a human operator and translates this mand into the motion of actuators which move the mechanical structure. The definition of this control system is purposely left vague in order not to impose any constraints on its design. The control system consists of actuators which move the mechanical structure, a means of controlling the actuators, a means of supplying power to the actuators, and a way of accepting inputs from the operator. It is this control system which is the target of this thesis. The goal is to analyze the requirments made on the control system and present guidelines for the gesign of new control systems. The thesis will be split into five parts: 1. Analysis of the requirements of the control system, from the perspective of the operator, the mechanical system, efficiency, stability, and safety requirements. 2. Analysis of current control systems and what their problems are. 3. Analysis of the different options for the control system: different types of actuators different types of control strategies, and different ways of anizing ponents. 4. Presentation of a new type of control system, which is mercially implementable. A system that will meet the needs of industry in the near future. 畢業(yè)設(shè)計(jì)（論文） 28 5. Analysis of more optimized systems, with higher performance, better efficiency, more flexible control, etc. This will be less mercially applicable but will be a starting point for more research. 2 SECTIONS OF THE THESIS Requirements Analysis of the Control System Before starting detailed work on developing new control systems, it is important to analyze what the exact demands are on the control system. The control system is influenced by many example: the mechanical structure it is controlling, the human operator, efficiency, stability, and industry requlations. Industry regulations are the first requirements that have to be addressed. Things like hose rupture protection and runaway load protection make a lot of demands on the control system. After regulations, stability is the next most important requirement