機械設計外文翻譯--液壓系統(tǒng)

1、<p><b>　　液壓系統(tǒng)</b></p><p>　　液壓傳動和氣壓傳動稱為流體傳動，是根據17世紀帕斯卡提出的液體靜壓力傳動原理而發(fā)展起來的一門新興技術，1795年英國約瑟夫?布拉曼(Joseph Braman,1749-1814)，在倫敦用水作為工作介質，以水壓機的形式將其應用于工業(yè)上，誕生了世界上第一臺水壓機，1905年他將工作介質水改為油，又進一步得到改善。</p

2、><p>　　第一次世界大戰(zhàn)后液壓傳動廣泛應用，特別是1920年以后，發(fā)展更為迅速。液壓元件大約在 19 世紀末 20 世紀初的20年間，才開始進入正規(guī)的工業(yè)生產階段。1925 年維克斯發(fā)明了壓力平衡式葉片泵,為近代液壓元件工業(yè)或液壓傳動的逐步建立奠定了基礎。20 世紀初康斯坦丁?尼斯克對能量波動傳遞所進行的理論及實際研究，1910年對液力傳動(液力聯軸節(jié)、液力變矩器等)方面的貢獻，使這兩方面領域得到了發(fā)展。<

3、/p><p>　　第二次世界大戰(zhàn)期間,在美國機床中有30%應用了液壓傳動。應該指出,日本液壓傳動的發(fā)展較歐美等國家晚了近 20 多年。在 1955 年前后 , 日本迅速發(fā)展液壓傳動,1956 年成立了“液壓工業(yè)會”。近20-30 年間，日本液壓傳動發(fā)展之快，居世界領先地位。</p><p>　　液壓傳動有許多突出的優(yōu)點，因此它的應用非常廣泛，如一般工業(yè)用的塑料加工機械、壓力機械、機床等；行走機

4、械中的工程機械、建筑機械、農業(yè)機械、汽車等；鋼鐵工業(yè)用的冶金機械、提升裝置、軋輥調整裝置等；土木水利工程用的防洪閘門及堤壩裝置、河床升降裝置、橋梁操縱機構等；發(fā)電廠渦輪機調速裝置、核發(fā)電廠等等；船舶用的甲板起重機械（絞車）、船頭門、艙壁閥、船尾推進器等；特殊技術用的巨型天線控制裝置、測量浮標、升降旋轉舞臺等；軍事工業(yè)用的火炮操縱裝置、船舶減搖裝置、飛行器仿真、飛機起落架的收放裝置和方向舵控制裝置等。</p><p&g

5、t;　　一個完整的液壓系統(tǒng)由五個部分組成，即動力元件、執(zhí)行元件、控制元件、輔助元件和液壓油。 </p><p>　　動力元件的作用是將原動機的機械能轉換成液體的壓力能，指液壓系統(tǒng)中的油泵，它向整個液壓系統(tǒng)提供動力。液壓泵的結構形式一般有齒輪泵、葉片泵和柱塞泵。 </p><p>　　執(zhí)行元件(如液壓缸和液壓馬達)的作用是將液體的壓力能轉換為機械能，驅動負載作直線往復運動或回轉運動。 &l

6、t;/p><p>　　控制元件(即各種液壓閥)在液壓系統(tǒng)中控制和調節(jié)液體的壓力、流量和方向。根據控制功能的不同，液壓閥可分為壓力控制閥、流量控制閥和方向控制閥。壓力控制閥又分為益流閥(安全閥)、減壓閥、順序閥、壓力繼電器等；流量控制閥包括節(jié)流閥、調整閥、分流集流閥等；方向控制閥包括單向閥、液控單向閥、梭閥、換向閥等。根據控制方式不同，液壓閥可分為開關式控制閥、定值控制閥和比例控制閥。 </p><

7、p>　　輔助元件包括油箱、濾油器、油管及管接頭、密封圈、壓力表、油位油溫計等。 </p><p>　　液壓油是液壓系統(tǒng)中傳遞能量的工作介質，有各種礦物油、乳化液和合成型液壓油等幾大類。 </p><p>　　液壓系統(tǒng)的作用就是幫助人類做工。主要是由執(zhí)行元件把壓力變成轉動或往復運動。 </p><p>　　液壓系統(tǒng)由信號控制和液壓動力兩部分組成，信號控制部分用于

8、驅動液壓動力部分中的控制閥動作。</p><p>　　液壓動力部分采用回路圖方式表示，以表明不同功能元件之間的相互關系。液壓源含有液壓泵、電動機和液壓輔助元件；液壓控制部分含有各種控制閥，其用于控制工作油液的流量、壓力和方向；執(zhí)行部分含有液壓缸或液壓馬達，其可按實際要求來選擇。</p><p>　　在分析和設計實際任務時，一般采用方框圖顯示設備中實際運行狀況。 空心箭頭表示信號流，而實心箭

9、頭則表示能量流。</p><p>　　基本液壓回路中的動作順序—控制元件（二位四通換向閥）的換向和彈簧復位、執(zhí)行元件（雙作用液壓缸）的伸出和回縮以及溢流閥的開啟和關閉。 對于執(zhí)行元件和控制元件，演示文稿都是基于相應回路圖符號，這也為介紹回路圖符號作了準備。</p><p>　　根據系統(tǒng)工作原理，您可對所有回路依次進行編號。如果第一個執(zhí)行元件編號為0，則與其相關的控制元件標識符則為1。如果與

10、執(zhí)行元件伸出相對應的元件標識符為偶數，則與執(zhí)行元件回縮相對應的元件標識符則為奇數。 不僅應對液壓回路進行編號，也應對實際設備進行編號，以便發(fā)現系統(tǒng)故障。</p><p>　　DIN ISO1219-2標準定義了元件的編號組成，其包括下面四個部分：設備編號、回路編號、元件標識符和元件編號。如果整個系統(tǒng)僅有一種設備，則可省略設備編號。</p><p>　　實際中，另一種編號方式就是對液壓系統(tǒng)中

11、所有元件進行連續(xù)編號，此時，元件編號應該與元件列表中編號相一致。 這種方法特別適用于復雜液壓控制系統(tǒng)，每個控制回路都與其系統(tǒng)編號相對應</p><p>　　與機械傳動、電氣傳動相比，液壓傳動具有以下優(yōu)點：</p><p>　　1、液壓傳動的各種元件，可以根據需要方便、靈活地來布置。</p><p>　　2、重量輕、體積小、運動慣性小、反應速度快。</p>

12、<p>　　3、操縱控制方便，可實現大范圍的無級調速（調速范圍達2000：1）。</p><p>　　4、可自動實現過載保護。</p><p>　　5、一般采用礦物油作為工作介質，相對運動面可自行潤滑，使用壽命長。</p><p>　　6、很容易實現直線運動。</p><p>　　7、很容易實現機器的自動化。

13、 </p><p><b>　　液壓系統(tǒng)的缺點：</b></p><p>　　1、由于流體流動的阻力和泄露較大，所以效率較低。如果處理不當，泄露不僅污染 場地，而且還可能引起火災和爆炸事故。</p><p>　　2、由于工作性能易受到溫度變化的影響，因此不宜在很高或很低的溫度條件下工作。</p><p>

14、;　　3、液壓元件的制造精度要求較高，因而價格較貴。</p><p>　　4、由于液體介質的泄露及可壓縮性影響，不能得到嚴格的傳動比。</p><p>　　5、液壓傳動出故障時不易找出原因；使用和維修要求有較高的技術水平。</p><p>　　在液壓系統(tǒng)及其系統(tǒng)中，密封裝置用來防止工作介質的泄漏及外界灰塵和異物的侵入。其中起密封作用的元件，即密封件。外漏會造成工作介

15、質的浪費，污染機器和環(huán)境，甚至引起機械操作失靈及設備人身事故。內漏會引起液壓系統(tǒng)容積效率急劇下降，達不到所需要的工作壓力，甚至不能進行工作。侵入系統(tǒng)中的微小灰塵顆粒，會引起或加劇液壓元件摩擦副的磨損，進一步導致泄漏。</p><p>　　因此，密封件和密封裝置是液壓設備的一個重要組成部分。它的工作的可靠性和使用壽命，是衡量液壓系統(tǒng)好壞的一個重要指標。除間隙密封外，都是利用密封件，使相鄰兩個偶合表面間的間隙控制在需

16、要密封的液體能通過的最小間隙以下。在接觸式密封中，分為自封式壓緊型密封和自封式自緊型密封（即唇形密封）兩種。</p><p><b>　　液壓系統(tǒng)的三大頑疾</b></p><p>　　1、發(fā)熱 由于傳力介質（液壓油）在流動過程中存在各部位流速的不同，導致液體內部存在一定的內摩擦，同時液體和管路內壁之間也存在摩擦，這些都是導致液壓油溫度升高的原因。溫度升高將導致內外泄

17、漏增大，降低其機械效率。同時由于較高的溫度，液壓油會發(fā)生膨脹，導致壓縮性增大，使控制動作無法很好的傳遞。解決辦法：發(fā)熱是液壓系統(tǒng)的固有特征，無法根除只能盡量減輕。使用質量好的液壓油、液壓管路的布置中應盡量避免彎頭的出現、使用高質量的管路以及管接頭、液壓閥等。</p><p>　　2、振動 液壓系統(tǒng)的振動也是其痼疾之一。由于液壓油在管路中的高速流動而產生的沖擊以及控制閥打開關閉過程中產生的沖擊都是系統(tǒng)發(fā)生振動的原因

18、。強的振動會導致系統(tǒng)控制動作發(fā)生錯誤，也會使系統(tǒng)中一些較為精密的儀器發(fā)生錯誤，導致系統(tǒng)故障。解決辦法：液壓管路應盡量固定，避免出現急彎。避免頻繁改變液流方向，無法避免時應做好減振措施。整個液壓系統(tǒng)應有良好的減振措施，同時還要避免外來振源對系統(tǒng)的影響。</p><p>　　3、泄漏 液壓系統(tǒng)的泄漏分為內泄漏和外泄漏。內泄漏指泄漏過程發(fā)生在系統(tǒng)內部，例如液壓缸活塞兩邊的泄漏、控制閥閥芯與閥體之間的泄漏等。內泄漏雖然不

19、會產生液壓油的損失，但是由于發(fā)生泄漏，既定的控制動作可能會受到影響，直至引起系統(tǒng)故障。外泄漏是指發(fā)生在系統(tǒng)和外部環(huán)境之間的泄漏。液壓油直接泄漏到環(huán)境中，除了會影響系統(tǒng)的工作環(huán)境外，還會導致系統(tǒng)壓力不夠引發(fā)故障。泄漏到環(huán)境中的液壓油還有發(fā)生火災的危險。解決辦法：采用質量較好的密封件，提高設備的加工精度。</p><p>　　液壓元件將向高性能、高質量、高可靠性、系統(tǒng)成套方向發(fā)展；向低能耗、低噪聲、振動、無泄漏以及污

20、染控制、應用水基介質等適應環(huán)保要求方向發(fā)展；開發(fā)高集成化高功率密度、智能化、機電一體化以及輕小型微型液壓元件；積極采用新工藝、新材料和電子、傳感等高新技術。</p><p>　　液力偶合器向高速大功率和集成化的液力傳動裝置發(fā)展，開發(fā)水介質調速型液力偶合器和向汽車應用領域發(fā)展，開發(fā)液力減速器，提高產品可靠性和平均無故障工作時間；液力變矩器要開發(fā)大功率的產品，提高零部件的制造工藝技術，提高可靠性，推廣計算機輔助技術，

21、開發(fā)液力變矩器與動力換檔變速箱配套使用技術；液粘調速離合器應提高產品質量，形成批量，向大功率和高轉速方向發(fā)展。</p><p>　　Hydraulic System</p><p>　　Hydraulic presser drive and air pressure drive hydraulic fluid as the transmission is made according to

22、 the 17th century, Pascal's principle of hydrostatic pressure to drive the development of an emerging technology, the United Kingdom in 1795 ? Braman Joseph (Joseph Braman ,1749-1814), in London water as a medium to

23、form hydraulic press used in industry, the birth of the world's first hydraulic press. Media work in 1905 will be replaced by oil-water and further improved.</p><p>　　After the World War ,because of the

24、extensive application of hydraulic transmission, espec- ially after 1920, more rapid development. Hydraulic components in the late 19th century about the early 20th century, 20 years, only started to enter the formal pha

25、se of industrial production. 1925 Vickers (F. Vikers) the invention of the pressure balanced vane pump, hydraulic components for the modern industrial or hydraulic transmission of the gradual establishment of the foundat

26、ion. The early 20th cent</p><p>　　The Second World War period, in the United States 30% of machine tool applications in the hydraulic transmission. It should be noted that the development of hydraulic transm

27、ission in Japan than Europe and the United States and other countries for nearly 20 years later. Before and after in 1955, the rapid development of Japan's hydraulic drive, set up in 1956, "Hydraulic Industry.&q

28、uot; Nearly 20 to 30 years, the development of Japan's fast hydraulic transmission, a world leader.</p><p>　　Hydraulic transmission There are many outstanding advantages, it is widely used, such as gener

29、al industr- ial use of plastics processing machinery, the pressure of machinery, machine tools, etc.; operating machinery engineering machinery, construction machinery, agricultural machinery, automobiles, etc.; iron and

30、 steel indu- stry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flo- od control and dam gate devices, bed lifts installations, b</p><p>　　A complete

31、hydraulic system consists of five parts, namely, power components, the implementation of co- mponents, control components, auxiliary components and hydraulic oil. The role of dynamic components of the original motive

32、 fluid into mechanical energy to the pressure that the hydraulic system of pumps, it is to power the entire hydraulic system. The structure of the form of hydra- ulic pump gears are generally pump, vane pump and piston p

33、ump. Implementation of components (such as hy</p><p>　　Control components (that is, the various hydraulic valves) in the hydraulic system to control and regulate the pressure of liquid, flow rate and dir

34、ection. According to the different control functions, hydraulic pressure control valve can be divided into valves, flow control valves and directional control valve. Pressure control valves are divided into benefits flow

35、 valve (safety valve), pressure relief valve, sequence valve, pressure relays, etc.; flow control valves including throttle, adjusti</p><p>　　The role of the hydraulic system is to help humanity work. Mainly

36、 by the implementation of components to rotate or pressure into a reciprocating motion.   Hydraulic system and hydraulic power control signal is composed of two parts, the signal control of some parts of the hydrau

37、lic power used to drive the control valve movement. Part of the hydraulic power means that the circuit diagram used to show the different functions of the interrelationship between components. Containing the source of h

38、</p><p>　　In the analysis and design of the actual task, the general block diagram shows the actual operation of equi - pment. Hollow arrow indicates the signal flow, while the solid arrows that energy flow.

39、 Basic hydraulic circuit of the action sequence - Control components (two four-way valve) and the spring to reset for the implementation of components (double-acting hydraulic cylinder), as well as the extending and

40、 retracting the relief valve opened and closed . For the implementation of componen</p><p>　　Working principle of the system, you can turn on all circuits to code. If the first implementation of components n

41、umbered 0, the control components associated with the identifier is 1. Out with the implementation of components corresponding to the identifier for the even components, then retracting and implementation of components c

42、orresponding to the identifier for the odd components. Hydraulic circuit carried out not only to deal with numbers, but also to deal with the actual device ID, in ord</p><p>　　DIN ISO1219-2 standard definiti

43、on of the number of component composition, which includes the following four parts: device ID, circuit ID, component ID and component ID. The entire system if only one device, device number may be omitted. Practice,

44、another way is to code all of the hydraulic system components for numbers at this time, components and component code should be consistent with the list of numbers. This method is particularly applicable to complex hydra

45、ulic control system, each con</p><p>　　With mechanical transmission, electrical transmission compared to the hydraulic drive has the following advantages: 1, a variety of hydraulic components, can easil

46、y and flexibly to layout. 2, light weight, small size, small inertia, fast response. 3, to facilitate manipulation of control, enabling a wide range of stepless speed regulation (speed range of 2000:1). 4,

47、 to achieve overload protection automatically. 5, the general use of mineral oil as a working medium, the r</p><p>　　The shortcomings of the hydraulic system: 1, as a result of the resistance to fl

48、uid flow and leakage of the larger, so less efficient. If not handled properly, leakage is not only contaminated sites, but also may cause fire and explosion. 2, vulnerable performance as a result of the impact of t

49、emperature change, it would be inappropriate in the high or low temperature conditions. 3, the manufacture of precision hydraulic components require a higher, more expensive and hence the pr</p><p>　　In

50、 the hydraulic system and its system, the sealing device to prevent leakage of the work of media within and outside the dust and the intrusion of foreign bodies. Seals played the role of components, namely seals. Medium

51、will result in leakage of waste, pollution and environmental machinery and even give rise to malfunctioning machinery and equipment for personal accident. Leakage within the hydraulic system will cause a sharp drop in vo

52、lumetric efficiency, amounting to less than the required p</p><p>　　Therefore, seals and sealing device is an important hydraulic equipment components. The reliability of its work and life, is a measure of t

53、he hydraulic system an important indicator of good or bad. In addition to the closed space, are the use of seals, so that two adjacent coupling surface of the gap between the need to control the liquid can be sealed foll

54、owing the smallest gap. In the contact seal, pressed into self-seal-style and self-styled self-tight seal (ie, sealed lips) two.</p><p>　　The three hydraulic system diseases 1, as a result of heat trans

55、mission medium (hydraulic oil) in the flow velocity in various parts of the existence of different, resulting in the existence of a liquid within the internal friction of liquids and pipelines at the sam- e time there is

56、 friction between the inner wall, which are a result of hydraulic the reasons for the oil tempera- ture. Temperature will lead to increased internal and external leakage, reducing its mechanical efficiency. At t</p>

57、;<p>　　2, the vibration of the vibration of the hydraulic system is also one of its malaise. As a result of hydraulic oil in the pipeline flow of high-speed impact and the control valve to open the closure of the

58、impact of the process are the reasons for the vibration system. Strong vibration control action will cause the system to error, the system will also be some of the more sophisticated equipment error, resulting in system

59、failures. Solutions: hydraulic pipe should be fixed to avoid sharp bends. </p><p>　　3, the leakage of the hydraulic system leak into inside and outside the leakage leakage. Leakage refers to the process with

60、 the leak occurred in the system, such as hydraulic piston-cylinder on both sides of the leakage, the control valve spool and valve body, such as between the leakage. Although no internal leakage of hydra- ulic fluid los

61、s, but due to leakage, the control of the established movements may be affected until the cause system failures. Outside means the occurrence of leakage in t</p><p>　　Another: the hydraulic system for the th

62、ree diseases, it was summed up: "fever, with a father(This is the summary of the northeast people). Hydraulic system for the lifts, excavators, pumping station, dynamic, crane, and so on large-scale industry, constr

63、uction, factories, enterprises, as well as elevators, lifting platforms, Deng Axle industry and so on. Hydraulic components will be high-performance, high-quality, high reliability, the system sets the direction of