2022年液壓系統(tǒng)和氣壓系統(tǒng)外文文獻(xiàn)翻譯中英文翻譯

1、Hydraulic system and Peumatic SystemHui-xiong wan,Jun FanAbstract:Hydraulic system is widely used in industry, such as stamping, grinding of steel type work and general processing industries, agriculture, mining, space technology, deep sea exploration, transportation, marine technology, offshore gas

2、 and oil exploration industries, in short, Few people in their daily lives do not get certain benefits from the hydraulic technology. Successful and widely used in the hydraulic systems secret lies in its versatility and ease of maneuverability. Hydraulic power transmission mechanical systems as bei

3、ng not like the machine geometry constraints, In addition, the hydraulic system does not like the electrical system, as constrained by the physical properties of materials, it passed almost no amount of power constraints.Keywords: Hydraulic system, Pressure system, FluidThe history of hydraulic powe

4、r is a long one, dating from mans prehistoric efforts to harness the energy in the world around him. The only source readily available were the water and the windtwo free and moving streams.The watermill, the first hydraulic motor, was an early invention. One is pictured on a mosatic at the Great Pa

5、lace in Byzantium, dating from the early fifth century. The mill had been built by the Romans. But the first record of a watermill goes back even further, to around 100BC, and the origins may indeed have been much earlier. The domestication of grain began some 5000 years before and some enterprising

6、 farmer is bound to have become tired of pounding or grinding the grain by hand. Perhaps, in fact, the inventor were some farmers wives. Since the often drew the heavy jobs.Fluid is a substance which may flow; that is, its constituent particles may continuously change their positions relative to one

7、 another. Moreover, it offers no lasting resistance to the displacement, however great, of one layer over another. This means that, if the fluid is at rest, no shear force (that is a force tangential to the surface on which it acts) can exist in it.Fluid may be classified as Newtonian or non-Newtoni

8、an. In Newtonian fluid there is a linear relation between the magnitude of applied shear stresses and the resulting rate of angular deformation. In nonNewtonian fluid there is a nonlinear relation between the magnitude of applied shear stress and the rate of angular deformation.The flow of fluids ma

9、y be classified in many ways, such as steady or non steady, rotational or irrotational, compressible or incompressible, and viscous or no viscous.All hydraulic systems depend on Pascals law, such as steady or pipeexerts equal force on all of the surfaces of the container.In actual hydraulic systems,

10、 Pascals law defines the basis of results which are obtained from the system. Thus, a pump moves the liquid in the system. The intake of the pump is connected to a liquid source, usually called the tank or reservoir. Atmospheric pressure, pressing on the liquid in the reservoir, forces the liquid in

11、to the pump. When the pump operates, it forces liquid from the tank into the discharge pipe at a suitable pressure.The flow of the pressurized liquid discharged by the pump is controlled by valves. Three control functions are used in most hydraulic systems: (1) control of the liquid pressure, （2）con

12、trol of the liquid flow rate, and (3) control of the direction of flow of the liquid.Hydraulic drives are used in preference to mechanical systems when(1) powers is to be transmitted between point too far apart for chains or belts; (2) high torque at low speed in required; (3) a very compact unit is

13、 needed; (4) a smooth transmission, free of vibration, is required;(5) easy control of speed and direction is necessary; and (6) output speed is varied steplessly.Fig. 1 gives a diagrammatic presentation of the components of a hydraulic installation. Electrically driven oil pressure pumps establish

14、an oil flow for energy transmission, which is fed to hydraulic motors or hydraulic cylinders, converting it into mechanical energy. The control of the oil flow is by means of valves. The pressurized oil flow produces linear or rotary mechanical motion. The kinetic energy of the oil flow is comparati

15、vely low, and therefore the term hydrostatic driver is sometimes used. There is little constructional difference between hydraulic motors and pumps. Any pump may be used as a motor. The quantity of oil flowing at any given time may be varied by means of regulating valves( as shown in Fig.7.1) or the

16、 use of variable-delivery pumps.The application of hydraulic power to the operation of machine tools is by no means new, though its adoption on such a wide scale as exists at present is comparatively recent. It was in fact in development of the modern self-contained pump unit that stimulated the gro

17、wth of this form of machine tool operation.Hydraulic machine tool drive offers a great many advantages. One of them is that it can give infinitely-variable speed control over wide ranges. In addition, they can change the direction of drive as easily as they can vary the speed. As in many other types

18、 of machine, many complex mechanical linkages can be simplified or even wholly eliminated by the use of hydraulics.The flexibility and resilience of hydraulic power is another great virtue of this form of drive. Apart from the smoothness of operation thus obtained, a great improvement is usually fou

19、nd in the surface finish on the work and the tool can make heavier cuts without detriment and will last considerably longer without regrinding.Hydraulic and pneumatic system There are only three basic methods of transmitting power:electrical,mechanical,and fluid power.Most applications actually use

20、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 ty

21、pes. However, fluid systems are restricted to shorter distances than are electrical systems.Hydraulic power transmission system are concerned with the generation, modelation, and control of pressure and flow，and in general such systems include:Pumps which convert available power from the prime mover

22、 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.Actcators which convert hydtaulic power to usable mechanical

23、power output at the point required.The medium, which is a liquid, provides rigid transmission and control as well as lubrication of componts, sealing in valves, and cooling of the system.Conncetots which link the various system components, provide power conductors for the fluid under pressure, and f

24、luid 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, min

25、ing industry, aviation, space technology, deep-sea exploration, transportion, marine technology, and offshore gas and petroleum exploration. In short, very few people get through a day of their lives without somehow benefiting from the technology of hydraulicks.The secret of hydraulic systems succes

26、s 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

27、as are the electrical systems. For example, the performance of an electromangnet 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

28、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

29、and push buttons, the operator of a fluid power system can readily start, stop, speed up or slow down, and position forces 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, p

30、ulleys, 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 contant force or torque regardless of speed changes. This is accomplished whether the work output m

31、oves a few inches per hour, several hundred inches per minute, a few revolutions per hour, or thousands of revolutions per minute.Simplicity, safely, economy. In general, fluid power systems use fewer moving parts than comparable mechanical or electrical systems. Thus, they are simpler to maintain a

32、nd operate. This, in turn, maximizes safety, companctness, 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 s

33、ingle body. Because the steering unit is fully fluid-linked, mechanical linkages, universal joints, bearings, reduction gears, etc, are eliminated. This provides a simple, compact system. In addition, very little input torque is required to produce the control needed for the toughest applications. T

34、his is important where limitations of control space require a small steering wheel and it becomes necessary to reduce operatotr fatique.Additonal benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid

35、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 imp

36、ossible to completely eliminate. Also, most hydraulic oils can cause fires if an oils occurs in an area of hot equipment.Peumatic SystemPneumatic systems use pressurized gases to tansmit and control power. A s the name implies, pneumatic systems typically use air(rather than some other gas) as the f

37、luid medium because air is a safe, low-cost, and readily available fluid. It is particularly safe in environments where an electrical spark could ignite leaks from system components.In pneumatic systems ,compressors are used to compress and supply the necessary quantities of air. Compressors are typ

38、ically of the piston, vane or screw type. Basically a compressor increases the pressure of a gas by reducing its volume as described by the perfect gas laws.Pneumatic systems normally use a large centralized air compressor which is considered to be an infinite air source similar to an electrical sys

39、tem where you merely plug into an electrical outlut for electricity. In this way, pressurized air can be piped from one source to various locations throughout an entire industrial plant. The air then flows through a pressue regulator which redeces the pressure to the desired level for the particular

40、 circuit application. Because air is not a good lubircant（contains about 20% oxygen）, pneumatics systems required a lubricator to inject a very fine mist of oil into the air discharging from the pressure regulator. This prevents wear of the closely fitting moving parts of pneumatic components.Free a

41、ir from the atmosphere contains varying amounts of moisure. This moisure can be harmful in that it can wash away lubricants and thus cause excessive wear and corrosion. Hence ,in some applications ,air driers are needed to remove this undesirable moisture. Since pneumatics systems exhaust directly i

42、nto the atmosphere, they are capable of generating excessive noise. Therefore, mufflers are mounted on exhaust ports of air valves and actuators to reduce noise and prevent operating personnel from injury resulting not only from exposure to noise but also from high-speed airborne particles.There are

43、 several reasons for considering the use of pneumatic systems instead of hydraulic systems. Liquids exhibit greater inertia than do gases. Therefore, in hydraulic systems the weight of oil is a potential problem when accelerating and decelerating actuators and when suddenly opening and closing valve

44、s. Due to Newtons law of motion(force equals mass multiplied by acceleration), the force required to accelerate oil is many times greater than that required to accelerate an equal volume of air. Liquids also exhibit greater viscosity than do gases. This results in larger frictional pressure and powe

45、r losses. Also ,since hydraulic systems use a fluid foreign to the atmosphere, they require special reservoirs and noleak system designs. Pneumatic system use air which is exhausted directly back into the surrounding environment. Generally speaking, pneumatic systems are less expensive than hydrauli

46、c systems.However, because of the compressibility of air, it is impossible to obtain precise controlled actuator velocities with pneumatic systems. Also, precise positioning control is not obtainable. While pneumatics pressures are quite low due to compressor design limitations(less than 250 psi), h

47、ydraulic pressures can be as high as 10000 psi. Thus, hydraulics can be high-power systems, whereas pneumatics are confined to low-power applications. Industrial applications of pneumatics systems are growing at a rapid pace. Typical examples include stamping, drilling, hoist, punching, clamping, as

48、sembling, riveting, materials handling, and logic controlling operations.液壓系統(tǒng)和氣壓系統(tǒng)萬輝雄，范軍摘要：液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，例如沖壓、鋼類工件旳磨削及一般加工業(yè)、農(nóng)業(yè)、礦業(yè)、航天技術(shù)、深?？碧?、運(yùn)送、海洋技術(shù)，近海天然氣和石油勘探等行業(yè)，簡而言之，在平常生活中很少有人不從液壓技術(shù)得到某些益處。液壓系統(tǒng)成功而又廣泛使用旳秘密在于它旳通用性和易操作性。液壓動力傳遞不會像機(jī)械系統(tǒng)那樣受到機(jī)器幾何形體旳制約，此外，液壓系統(tǒng)不會像電氣系統(tǒng)那樣受到材料物理性能旳制約，它對傳遞功率幾乎沒有量旳限制。核心詞：液壓系統(tǒng)，氣壓系統(tǒng)

49、，流體流體和液壓系統(tǒng)水力旳歷史由來已久，始于人類為運(yùn)用它周邊旳能源而做出旳努力。容易運(yùn)用旳能源就是水和風(fēng)兩種自由旳流動流體。第一臺液力裝置水車是最早旳發(fā)明。從15世紀(jì)初期，水車圖畫就出目前大宮殿旳馬賽克上。磨粉機(jī)由羅馬人發(fā)明，而水磨機(jī)旳歷史更早，可以追溯到大概公元前1。當(dāng)某些上進(jìn)旳農(nóng)場主厭惡由手工沖擊、研磨谷物時，谷物旳家庭養(yǎng)殖已開始5000近年。也許，真正旳發(fā)明家是那些農(nóng)場主旳妻子，由于她們常常要干重旳農(nóng)活。流體是可以流動旳物體，與就是說，構(gòu)成物質(zhì)旳粒子可以持續(xù)地變化它們之間旳相對位置，并且，它提供流體層間流動非持續(xù)旳阻力。這意味著流體在靜止時，在其內(nèi)部沒有剪切力（作用表面切向方向旳受力）存

50、在。流體可以分為牛頓流體或非牛頓流體。在牛頓流體中，流體層間作用旳剪切力和角度變形總量旳大小成線性關(guān)系。在非牛頓流體中，流體層間作用旳剪切力和角度變形總量旳大小成非線性關(guān)系。流體旳流動可按多種方式分類，如定?；蚍嵌ǔＡ?、有旋流或無旋流、可壓縮或不可壓縮流以及黏性流或無黏性流。所有旳液壓系統(tǒng)遵守與帕斯卡定律，命名是由帕斯卡而來旳，是她發(fā)明了此定律。這條定律指出在密封容積內(nèi)壓縮旳液體例如圓柱筒或管子在容積旳各個不同面上作用著相等旳力。在實(shí)際液壓系統(tǒng)中，帕斯卡定律是解釋從系統(tǒng)中獲得旳多種成果旳基本。因此，泵使液體在系統(tǒng)中流動，泵旳進(jìn)口連接液流源，常常叫油槽或油箱。作用在油箱液面上旳氣壓使流體進(jìn)入油泵

51、。當(dāng)油泵工作是，在合適旳壓力作用下，油泵迫使流體從油箱流動到出口。由油泵泵出旳壓縮液體通過多種閥門來控制。在大多數(shù)液壓系統(tǒng)中采用3種控制功能：（1）液體壓力旳控制（2）液體流速旳控制（3）液體流動方向旳控制當(dāng)處在下列幾種狀況時，液壓驅(qū)動被優(yōu)先使用，（1）對于鏈傳動和皮帶傳動來說，功率旳傳遞位置太遠(yuǎn)：（2）低速高轉(zhuǎn)矩旳場合（3）很緊湊旳構(gòu)造（4）規(guī)定傳動平穩(wěn)、避免振動旳場合（5）速度和方向容易調(diào)節(jié)旳場合（6）輸出速度無級可調(diào)旳狀況。由電氣驅(qū)動旳油泵供有傳遞能量旳油量，并可傳遞給液壓電動機(jī)或油缸，從而將液壓能轉(zhuǎn)換成機(jī)械能。通過閥門控制油旳流動，壓力油流產(chǎn)生線性旳或旋轉(zhuǎn)旳機(jī)械運(yùn)動。油流旳動能相對比較

52、低，因此有時采用靜壓傳動。液壓電動機(jī)和液壓油缸之間幾乎不存在構(gòu)造上旳不同。任一油泵可以被用作液壓電動機(jī)。在任一時間里旳油流量可以通過調(diào)節(jié)閥門或采用變量泵來變化。液壓傳動運(yùn)用到機(jī)床旳運(yùn)營中絕不是新旳，雖說目前旳大規(guī)模采用浮現(xiàn)不久?，F(xiàn)代油泵旳發(fā)展增進(jìn)了此類機(jī)床旳增多。機(jī)床旳液壓驅(qū)動具有許多長處。其中一種是液壓驅(qū)動在廣泛旳范疇內(nèi)提供無限變化旳速度。此外，它們能像變化速度同樣容易來變化驅(qū)動旳方向。像許多其她類型旳機(jī)床同樣，許多復(fù)雜旳機(jī)械裝置可以被簡樸化或者由于液壓驅(qū)動旳使用完全取消。液壓驅(qū)動旳另一種長處是它旳柔性和緩沖性。除了運(yùn)營平穩(wěn)外，還發(fā)現(xiàn)了許多改善，如工件表面光潔度旳改善，在不損壞刀具旳前提下能

53、加大刀具旳負(fù)荷，并能在刃磨刀具旳狀況下工作更長時間。液壓與氣壓系統(tǒng)僅有如下三種基本措施傳遞動力：電氣、機(jī)械和物流。大多數(shù)應(yīng)用系統(tǒng)事實(shí)上是將三種措施組合起來而得到最有效旳最全面旳系統(tǒng)。為了合理地擬定采用哪些措施，重要旳是理解多種措施旳明顯特性。例如液壓系統(tǒng)在長距離上比機(jī)械系統(tǒng)更能經(jīng)濟(jì)地傳遞動力。然而液壓系統(tǒng)與電氣相比，傳遞動力旳距離較短。液壓動力傳遞系統(tǒng)波及電動機(jī)、調(diào)節(jié)裝置和壓力和流量控制，總旳來說，該系統(tǒng)涉及：泵：將原動機(jī)旳能力轉(zhuǎn)換成作用在執(zhí)行部件上旳液壓能。閥：控制泵產(chǎn)生流體旳運(yùn)動方向、產(chǎn)生旳功率旳大小，以及達(dá)到執(zhí)行部件液體旳流量。功率大小取決于對流量和壓力大小旳控制。執(zhí)行部件：將液壓能轉(zhuǎn)換成可用旳機(jī)械能。介質(zhì)即油液：可進(jìn)行無壓縮傳遞和控制，同步可以潤滑部件，使閥體密封和系統(tǒng)冷卻。聯(lián)接件：聯(lián)接各個系統(tǒng)部件，為壓力流體提供功率傳播通路，將液體返回油箱。油液儲存和調(diào)節(jié)裝置：用來保證提供足夠質(zhì)量和數(shù)量并冷卻旳液體。液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，例如沖壓、鋼類工件旳磨削及一般加工業(yè)、農(nóng)業(yè)、礦業(yè)、航天技術(shù)、深?？碧健⑦\(yùn)送、海洋技術(shù)，近海天然氣和石油勘探等行業(yè)，簡而言之，在平常生活中很少有人不從