喜歡就充值下載吧。。。資源目錄里展示的全都有，，下載后全都有,,請放心下載，原稿可自行編輯修改=====================喜歡就充值下載吧。。。資源目錄里展示的全都有，，下載后全都有,,請放心下載，原稿可自行編輯修改=====================喜歡就充值下載吧。。。資源目錄里展示的全都有，，下載后全都有,,請放心下載，原稿可自行編輯修改=====================
Hydraulic System
There are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.
Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:
1.Pumps which convert available power from the prime mover to hydraulic power at the actuator.
2.Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.
3.Actuators which convert hydraulic power to usable mechanical power output at the point required.
4.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.
5.Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).
6.Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.
Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marine technology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.
The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.
Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.
Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.
Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.
Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.
Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small sterring wheel and it becomes necessary to reduce operator fatigue.
Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment.
There are only three basic methods of transmitting power: electrical, mechanical, and fluid power. Most applications actually use a combination of the three methods to obtain the most efficient overall system. To properly determine which principle method to use, it is important to know the salient features of each type. For example, fluid systems can transmit power more economically over greater distances than can mechanical types. However, fluid systems are restricted to shorter distances than are electrical systems.
Hydraulic power transmission system are concerned with the generation, modulation, and control of pressure and flow, and in general such systems include:
Pumps which convert available power from the prime mover to hydraulic power at the actuator.
Valves which control the direction of pump-flow, the level of power produced, and the amount of fluid-flow to the actuators. The power level is determined by controlling both the flow and pressure level.
Actuators which convert hydraulic power to usable mechanical power output at the point required.
The medium, which is a liquid, provides rigid transmission and control as well as lubrication of components, sealing in valves, and cooling of the system.
Connectors which link the various system components, provide power conductors for the fluid under pressure, and fluid flow return to tank (reservoir).
Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.
Hydraulic systems are used in industrial applications such as stamping presses, steel mills , and general manufacturing , agricultural machines , mining industry , aviation , space technology , deep-sea exploration ,transportation , marine technology , and offshore gas petroleum exploration . In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulics.
The secret of hydraulic system’s success and widespread use is its versatility and manageability. Fluid power is not hindered by the geometry of the machine as is the case in mechanical systems. Also, power can be transmitted in almost limitless quantities because fluid systems are not so limited by the physical limitations of materials as are the electrical systems. For example, the performance of an electromagnet is limited by the saturation limit of steel. On the other hand, the power limit of fluid systems is limited only by the strength capacity of the material.
Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.
1. Ease and accuracy of control. By the use of simple levers and push buttons, the operator of a fluid power systems can readily start, stop, speed up or slow down, and position force which provide any desired horsepower with tolerances as precise as one ten-thousandth of an inch.
2. Multiplication of force. A fluid power system (without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction of an ounce to several hundred tons of output.
3. Constant force or torque. Only fluid power systems are capable of providing constant force or torque regardless of speed changes. This is accomplished whether the work output moves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.
4. Simplicity, safety, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain and operate. This, in turn, maximizes safety, compactness, and reliability. For example, a new power steering control designed has made all other kinds of power systems obsolete on many off-highway vehicles. The steering unit consists of a manually operated directional control valve and meter in a single body. Because the sterring unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, ect . are eliminated. This provides a simple,compact systems.In addition, very little input torque is required to produce the control needed for the toughest applications. This is important where limitations of control space require a small sterring wheel and it becomes necessary to reduce operator fatigue.
Additional benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems also have the highest horsepower per weight ratio of any known power source. In spite of all these highly desirable features of fluid power, it is not a panacea for all power transmission problems. Hydraulic systems also have some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely. Also, most hydraulic oils can cause fires if an oil leak occurs in area of hot equipment.
液壓系統(tǒng)
僅有以下三種基本方法傳遞動力：電氣，機械和流體。大多數(shù)應用系統(tǒng)實際上是將三種方法組合起來而得到最有效的最全面的系。為了合理的確定采取哪種方法，重要的是了解各種方法的顯著特征。例如液壓系統(tǒng)在長距離上比機械系統(tǒng)更能經濟的傳遞動力。然而液壓系統(tǒng)與電氣系統(tǒng)相比，傳遞動力的距離較短。
液壓動力傳遞系統(tǒng)涉及電動機，調節(jié)裝置和壓力和流量控制，總的來說，該系統(tǒng)包括：
泵：將原動機的能量轉換成作用在執(zhí)行部件上所謂液壓能。
閥：控制泵產生流體的運動方向，產生的功率的大小，以及到達執(zhí)行部件液體的流量。功率大小取決與對流量和壓力大小的控制。
執(zhí)行部件：將液壓能轉換成可用的機械能。
介質即油液：可進行無壓縮傳遞和控制，同時可以潤滑部件，使閥體密封和系統(tǒng)冷卻。
聯(lián)結件：聯(lián)結各個系統(tǒng)部件，為壓力流體提供功率傳輸通路，將液體返回油箱（貯油器）。
油液貯存和調節(jié)裝置：用來確保提供足夠質量和數(shù)量并冷卻的液體。
液壓系統(tǒng)在工業(yè)中應用廣泛，例如沖壓，鋼類工件的磨削及一般加工業(yè)，農業(yè)，礦業(yè)，航天技術，深?？碧剑\輸，海洋技術，近海天然氣和石油勘探等行業(yè)，簡而言之，在日常生活中很少有人不從液壓技術中得到某種益處。
液壓系統(tǒng)成功而又廣泛使用的秘密在于它的通用性和易作性。液壓動力傳遞不會像機械系統(tǒng)那樣受到機器幾何形體的制約，另外，液壓系統(tǒng)不會像電氣系統(tǒng)那樣受到材料物理性能的制約，它對傳遞功率幾乎沒有量的限制。例如，一個電磁體的性能受到鋼的磁飽和極限的限制，相反，液壓系統(tǒng)的功率僅僅受材料強度的限制。
企業(yè)為了提高生產率將越來越依靠自動化，這包括遠程和直接控制生產操作，加工過程和材料處理等。液壓動力之所以成為自動化的重要組成分，是因為它有如下主要的四種優(yōu)點：
1. 控制方便精確 通過操作一個簡單的操作桿和按鈕，液壓系統(tǒng)的操作者便能立即啟動，停止，加減速和能提供任意功率，位置精度為萬分之一英寸的位置控制力。
2. 增力 一個液壓系統(tǒng)（沒有使用笨重的齒輪，滑輪和杠桿）
能簡單有效地將不到一盎司的力放大產生幾百噸力的輸出。
3. 恒力和恒扭矩 只有液壓系統(tǒng)能提供不隨速度變化的恒力或恒扭矩，它可以驅動對象從每小時移動幾英寸到每分鐘幾百英寸，從每小時幾百轉到每分鐘幾千轉。
4. 簡單，安全，經濟 總的來說，液壓系統(tǒng)比機械或電氣系統(tǒng)使用更少的運動部件，因此，它們運行與維護簡單。這使的系統(tǒng)結構緊湊，安全可靠。例如一種用于車輛上的新型動力轉向控制裝置已淘汰其他類型的轉向動力裝置，該轉向部件中包含有人力操作方向控制閥和分配器。因為轉向部件是全液壓的，沒有萬向節(jié)，軸承，減速齒輪等機械連接，這使得系統(tǒng)簡單緊湊。
另外，只需輸入很小的扭矩就能產生滿足極惡劣工作條件所需的控制力，這對于因操作空間限制而需要方向盤的場合很重要，這也是減輕司機疲勞度所必需的。
液壓系統(tǒng)的其他優(yōu)點包括雙向運動，過載保護和無級變速控制，在已有的任何動力系統(tǒng)中液壓系統(tǒng)亦具有最大的單位質量功率比。
盡管液壓系統(tǒng)具有如此高性能，但它不是可以解決所有動力傳遞問題的靈丹妙藥。液壓系統(tǒng)也有些缺點，液壓油有污染，并且泄露不可能完全避免，另外如果油液滲漏發(fā)生在灼熱設備附近，大多數(shù)液壓油能引起火災。
氣壓系統(tǒng)
氣壓系統(tǒng)是用壓力氣體傳遞和控制動力，正如名稱所表明的那樣，氣壓系統(tǒng)通常用空氣（不用其它的氣體）作為流體介質，因為空氣是安全、成本低而又隨處可得的流體，在系統(tǒng)部件中產生電弧有可能點燃泄露物的的場合下（使用空氣作為介質）尤其安全。
在氣壓系統(tǒng)中，壓縮機用來壓縮并供應所需的空氣。壓縮機一般有活塞式、葉片式和螺旋式等類型。壓縮機基本上是根據理想氣體法則，通過減小氣體體積來增加氣體壓力的。氣壓系統(tǒng)通?？紤]采用大的中央空氣壓縮機作為一個無限量的氣源，這類似于電力系統(tǒng)中只要將插頭插入插座便可獲得電能。用這種方法，壓力氣體可以從氣源輸送到整個工廠的各個角落，壓力氣體可通過空氣氣濾器除去污物，這些污物可能會損壞氣動組件的精密配合部件如閥和氣缸等，隨后輸送到各個回路中，接著空氣流經減壓閥以減小氣壓值適合某一回路使用。因為空氣
不是好的潤滑劑（包括20%的氧氣），氣壓系統(tǒng)需要一個油霧器將細小的油霧注射到經過減壓閥減壓的空氣中，這有助于減少氣動組件精密配合運動件的磨損。
由于來自大氣中的空氣含不同數(shù)量的水分，這些水分是有害的，它可以帶走潤滑劑引起過分磨損和腐蝕，因此，在一些使用場合中，要用空氣干燥器來除去這些有害的水分。由于氣壓系統(tǒng)直接 向大氣排氣，會產生過大噪音，因此可在氣閥和執(zhí)行組件排氣口安裝消聲器來降低噪音，以防止操作人員因接觸噪聲及高速空氣粒子有可能引發(fā)的危害。
用氣動系統(tǒng)代替液壓系統(tǒng)有以下幾條理由：液體的慣性遠比氣體大，因此，液壓系統(tǒng)中，當執(zhí)行組件加速和減速和閥突然開啟關閉時，油液的質量便是一個潛在的問題，根據牛頓運動定律（力等于質量乘以加速度），產生加速運動油液所需的力要比加速同等體積空氣的力高出許多倍4。液體比氣體具有更大的粘性，這會因為內摩擦而引起更大的壓力 和功率損失：另外，由于液壓系統(tǒng)使用的液體要與大氣隔絕，故他們需要特殊的油箱和無泄露系統(tǒng)設計。氣壓系統(tǒng)使用可以直接排到周圍環(huán)境中的空氣，一般來說氣壓系統(tǒng)沒有液體系統(tǒng)昂貴。
然而，由于空氣的可壓縮性，使得氣壓系統(tǒng)執(zhí)行組件不可能得到精確的速度控制和位置控制。氣壓系統(tǒng)由于壓縮機局限，其系統(tǒng)壓力相當?shù)停ǖ赜?50psi）,而液壓力可達1000psi之高，因此液壓系統(tǒng)可以是大功率系統(tǒng)，而氣動系統(tǒng)僅用于小功率系統(tǒng)，典型例子有沖壓、鉆孔、提升、沖孔、夾緊、組裝、鎦接、材料處理和邏輯控制操作等。
10
河南理工大學萬方科技學院
本科畢業(yè)設計（論文）開題報告
題目名稱
DZ型單體液壓支柱
學生姓名
王波
專業(yè)班級
機械設計3班
學號
08280700142
一、 選題的目的和意義：
隨著我國煤炭事業(yè)的不斷發(fā)展，單體液壓支柱也越來越多地廣泛用于生產，它與一般的金屬支柱相比回收率高，支護安全可靠性好，工作阻力恒定，初撐力高，不受井下過多條件的影響，頂板的下沉量小容易保護頂板完整，容易實現(xiàn)穩(wěn)定高產等優(yōu)點
。對于我國煤炭事業(yè)向普通機械化生產方向發(fā)展，并向綜合機械化生產過度都十分有利，它與液壓支架相比，能大量節(jié)省鋼材，并且適用范圍廣泛，但單體液壓支柱成本高，加工復雜，需要人工搬動所以設計時要求再能滿足強度要求的情況下盡可能的減輕重量，總的看來，廣泛研究新型液壓支柱對目前發(fā)展煤炭事業(yè)有著極其重要的意義。
本設計目的在于進一步簡化支柱結構，提高加工質量及支柱強度，降低成本。
二、 國內外研究綜述：
目前我國單體液壓支柱分類及發(fā)展狀況 單體液壓支柱單體液壓支柱由油缸、活柱、閥等零部件組成，以專用油或高含 水液壓液（含乳化液）等為工作液，供礦山支護用的單根支柱。屬于 恒阻式支柱，具有不變的額定工作阻力，它和金屬鉸接頂梁配合使 用，主要使用在煤礦回采工總面頂板支護、煤礦綜采工作面端頭支護 和回采工總面巷道的前支護臨時支護，可用于煤層傾角在 35°以下的 任何采煤工作面，支柱支護密度根據地質狀況和采煤方式而定。由于 煤層自身的賦存條件（如近水平煤層、斜煤層、急斜煤層、直倒立轉 煤層、 “雞窩”煤層等）和煤層賦存地質條件的復雜性（如在一塊煤 田中，有大落差的斷層，而較小的斷層更是層出不窮） ，在眾多的煤 礦井下支護產品中，單體液壓支柱與鉸接頂梁配合使用，具有投資 少、受地質條件限制少、使用和維護簡單方便且操作靈活等特點，是 我國和東南亞等國家煤礦工作面的支護的主導設備，與綜采液壓支架 等其他多種支護形式產品將長期并存發(fā)展。 單體支護設備經歷了三次飛躍發(fā)展，分別是 60 年代研制使用的 單體金屬摩擦支柱（現(xiàn)已基本淘汰） ，70 年代中期研制 80 年代推廣的 活塞式單體液壓支柱，90 年代末研制應用的 DWX 型柱塞懸浮式單體液 壓支柱，使單體支護設備及支護技術得到突破性發(fā)展。。
國外主要煤炭生產國中，單體液壓支柱曾經在回采工作面廣泛使用，最早使用國家在四十年代末就有該產品問世。其后，聯(lián)邦德國、日本、波蘭、蘇聯(lián)等國也相繼在五十年代使用。從國外單體液壓支柱的使用情況表明，在六十年代初期其技術即達到成熟階段。
三、畢業(yè)設計（論文）所用的主要技術與方法
1.?確定總體方案
2.利用液壓、機械原理、材料力學、理論力學等知識進行技術設計
3.在網上查閱相關資料
4.利用CAD或Pro\E計算機繪圖和手工方法繪制相關圖
5.對所選數(shù)據進行分析和計算
四、主要參考文獻與資料獲得情況：
1.李炳文 單體液壓支柱 煤炭工業(yè)部物資供應局出版社，2001
2. 成大先.機械設計手冊[K].3卷.北京:化學工業(yè)出版社,2007.
3. 成大先.機械設計手冊[K].4卷.北京:化學工業(yè)出版社,2007.
4. 機械制圖手冊
5. 成大先.機械設計手冊[K].2卷.北京:化學工業(yè)出版社,2007.
6. 劉鴻文 材料力學 M 北京教育出版社
五、畢業(yè)設計（論文）進度安排（按周說明）
第5~6周：查找資料，并確定自己的設計題目并完成開題報告；
第7~10周：開始著手計算與設計并繪制草圖;
第11~13周：計算機繪圖，繪制精圖；
第14~15周：修改并完成說明書；
第16 周：讓指導教師修改設計準備答辯
六、 指導教師審批意見：
指導教師： （簽名）
年 月 日
河南理工大學萬方科技學院
本科畢業(yè)設計（論文）中期檢查表
指導教師： 李延鋒 職稱： 教授
所在院（系）： 機械與動力工程學院 教研室（研究室）： 機械與動力工程部
題 目
單體液壓支柱
學生姓名
牛 翔
專業(yè)班級
08機設三班
學號
0828070142
一、選題質量：（主要從以下四個方面填寫：1、選題是否符合專業(yè)培養(yǎng)目標，能否體現(xiàn)綜合訓練要求；2、題目難易程度；3、題目工作量；4、題目與生產、科研、經濟、社會、文化及實驗室建設等實際的結合程度）
1、本題目符合機械設計專業(yè)的培養(yǎng)目標，能夠充分鍛煉和培養(yǎng)分析問題和實際操作能力，能夠體現(xiàn)綜合訓練的要求；
2、本題目難易適中，符合本科畢業(yè)設計要求；
3、本題目工作量適中，能在規(guī)定的時間內完成；
4、所選題目單體液壓支柱的設計與實際貼合比較緊密，在實際的應用中比較廣泛。在設計過程中，對機器的零件的設計和計算對我來說是以往所學知識的總結和應用，所以能夠滿足綜合訓練的要求
二、開題報告完成情況：
根據自己在各方面資料的收集和整理，通過對可行性的分析，結合實際因素，我完成了這次設計的選題。在選題結束之后，通過自己認真查閱相關的資料，最后結合本身的實際情況和設計的時間任務完成了開題報告。
三、階段性成果：
1、通過對單體液壓支柱的了解，再加上有關書籍的介紹，算是對單體液壓支柱有了一個大概的了解。前期階段主要是對有關于單體液壓支柱的各方面的文獻和資料進行搜集，為設計以后的設計做了必要的準備。
2、中期階段主要是依據參考資料，從上面找到一些關于關于單體液壓支柱的信息，首先對其零部件有了大致的了解，其次是已有了大概的設計方法，并開始了一些基本的結構設計。
3、正在進行裝配圖的CAD畫圖和設計說明書。
四、存在主要問題：
由于這是我第一次單獨進行單體液壓支柱總體設計，所以剛開始進展的并不是很順利。而我對這方面的知識掌握比較少，所以需要在圖書館和網上查找更多的相關資料，對有關起重機的知識進行更深入的了解。不過我堅信，只要自己努力和在指導老師的指引下，我能把各方面的問題逐個擊破，最終順利完成畢業(yè)設計。
五、指導教師對學生在畢業(yè)實習中，勞動、學習紀律及畢業(yè)設計（論文）進展等方面的評語
指導教師： （簽名）
年 月 日
2