【正文】 26 ＝1264w表 51 各種機械允許油溫 液壓設備類型 正常工作溫度/ C?最高允許溫度/ C?數(shù)控機床 30～50 55～70一般機床 30～55 55～70機車車輛 40～60 70～80船舶 30～60 80～90冶金機械、液壓機 407～0 60～90工程機械、礦山機械 50～80 70～90液壓系統(tǒng)中產(chǎn)生的熱量，由系統(tǒng)中各個散熱面散發(fā)至空氣中，其中油箱是主要散熱面。取散熱系數(shù) K=15，將數(shù)值代入公式（ 57）得： ＝????? ＝ C?此溫升超過了許用范圍， ＝30 －50 ，增大油箱面積，取???V＝814 ＝112L，并且取系數(shù) K=20 ，重新帶入數(shù)值計算得：Wm?A ＝??? ＝ C?所以滿足了許用溫升要求。并在滿足原有要求的情況下實現(xiàn)重量輕、體積小、成本低、效率高、結(jié)構(gòu)簡單、使用維護方便等的要求。湖南理工學院畢業(yè)設計（論文）29致謝本設計是在李實老師的悉心指導和嚴格要求下完成的。湖南理工學院畢業(yè)設計（論文）30參考文獻[1] [M].北京：機械工業(yè)出版社， 1997.[2] [M].河北科技大學教材，1999.[3] [M]. 制造技術與機床，1999， （10）.[4] [M].北京： 機械工業(yè)出版社，1995.[5] [M].北京： 機械工業(yè)出版社，2022.[6] [M].北京： 機械工業(yè)出版社，1994.[7] [M].廣州： 廣東高教出版社，1993.[8] [M].北京： 機械工業(yè)出版社，1993.[9] [M].：機械工業(yè)出版社，1995.[10] [M].哈爾濱：哈爾濱工業(yè)大學出版社，1998.[11] 陳 [M].北京:中國鐵道出版社，1982.[12] [M].徐州：中國礦業(yè)大學出版社，1988.[13] [M].沈陽：遼寧科學技術出版社，1993.[14] 張利平，[M] . 鍛壓機械，2022.[15] [J].MM 機械技術雜志（臺灣） ，2022.[16] 張利平. 近代液壓技術的幾個重要發(fā)展方向 [J].機械制造雜志，2022，8 月號（第 15卷第三期）.[17] Zhang Liping, Li Yingbo, Zhang Xiumin. Application Studies On Hydraulics amp。 Pneumatics, Nov, 2022.[20] Anthon Esposito. Fluid Power With Applications. New Jersey: Prent iceHall,1980.[21] Northman Co, Ltd New Products Guide.湖南理工學院畢業(yè)設計（論文）31CONTROL OF MOBILE HYDRAULIC CRANESMarc E. M220。 Jansson, Palmberg, 1990。de 101DK9220 Aalb. DenmarkEmail: mmuniet. auc. dkThe 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 INTRODUCTIONThe 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 湖南理工學院畢業(yè)設計（論文）32future.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 SystemBefore 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。 Technological Literature Publishers, 1995.[18] Schneider R T. Don’t Fet to Congsider Accumulators. Hydraulics amp。老師廣博的專業(yè)學識、嚴謹?shù)闹螌W態(tài)度以及執(zhí)著的事業(yè)追求使我受益匪淺，他嚴緊的科學作風和實事求是的科學態(tài)度給我留下了深刻的印象。在今后的工作學習中我會更加詳盡的學習，提高設計的科學性和效率。湖南理工學院畢業(yè)設計（論文）286 結(jié)論在本次關于數(shù)控銑床兩工位夾緊裝置液壓系統(tǒng)的畢業(yè)設計中，我通過查閱現(xiàn)有資料，應用液壓傳動的一般原理及液壓系統(tǒng)的設計原理，進行了液壓系統(tǒng)的功能原理設計、執(zhí)行元件的選擇、閥類元件的選型、集成塊設計、密封及液壓油的選擇等工作。當只考慮油箱散熱時，其散熱量 可按下式計算：0H ＝KA 0H??（5－6）式中 K——散熱系數(shù)（ ） ，計算時可選用推薦值：通風很差 K＝8；通/WmC?A風良好 K＝14－20；風扇冷卻時，K＝20－25；用循環(huán)水冷卻時，K＝110－175； A——油箱散熱面積； ——系統(tǒng)溫升。為此，必須對系統(tǒng)進行發(fā)熱和溫升計算，以便對系統(tǒng)溫升進行控制。因為Ⅱ工位夾緊缸的運動過程是一樣的，使用對此油缸的壓力校驗過程和上面的計算過程是一樣的。本設計取 =6，將數(shù)值代如公式（45）得：? V＝614 ＝84 L湖南理工學院畢業(yè)設計（論文）245 估算液壓系統(tǒng)性能 液壓系統(tǒng)壓力損失驗算由于系統(tǒng)的管路布置尚未具體確定，整個系統(tǒng)的壓力損失無法全面的計算，故只能先估算閥類元件的壓力損失，待設計好管路布置圖后，加上管路的沿程損失和局部損失即可。吸油管可安裝 100μm 左右的網(wǎng)式或線隙式過濾器，安裝位置要便于裝卸和清洗過濾器。油箱設計要點：1）油箱應有足夠的容積以滿足散熱，同時其容積應保證系統(tǒng)中油液全部流回油箱時不滲出，油液液面不應超過油箱高度的 80%；2）吸箱管和回油管的間距應盡量大，之間應設置隔板，以加大液流循環(huán)的途徑，這樣能提高散熱、分離空氣及沉淀雜質(zhì)的效果。其他油管，可直接按所連接的液壓元、輔件的接口尺寸決定其管徑的大小。將數(shù)值代入公式（43）得Ⅰ工位夾緊液壓缸： ＝d無 ???? ＝湖南理工學院畢業(yè)設計（論文）21 ＝d有 ???? ＝Ⅱ工位夾緊液壓缸：＝d無 34106???????? ＝ ＝d有 34106????