外文翻譯--液壓系統(tǒng)和氣壓系統(tǒng)

1、<p>　　Hydraulic system and Peumatic System</p><p>　　Hui-xiong wan,Jun Fan</p><p>　　School of mechanical science and Engineening,Huazhong univ.of science and technology,Wuhan,430074,China<

2、;/p><p>　　School of Logistics Engineening,Wuhan,univ.of science and technology,Wuhan,430063,China</p><p>　　Abstract:Hydraulic system is widely used in industry, such as stamping, grinding of steel

3、type work and general processing industries, agriculture, mining, space technology, deep sea exploration, transportation, marine technology, offshore gas and oil exploration industries, in short, Few people in their dail

4、y lives do not get certain benefits from the hydraulic technology. Successful and widely used in the hydraulic system's secret lies in its versatility and ease of maneuverability. Hydraulic </p><p>　　Key

5、words: Hydraulic system, Pressure system, Fluid</p><p>　　The history of hydraulic power is a long one, dating from man’s prehistoric efforts to harness the energy in the world around him. The only source rea

6、dily available were the water and the wind—two free and moving streams.</p><p>　　The watermill, the first hydraulic motor, was an early invention. One is pictured on a mosatic at the Great Palace in Byzantiu

7、m, 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 domestica

8、tion of grain began some 5000 years before and some enterprising farmer is bound to have become tired of pounding or grinding the grain by hand. Perhaps, </p><p>　　Fluid is a substance which may flow; that i

9、s, its constituent particles may continuously change their positions relative to one another. Moreover, it offers no lasting resistance to the displacement, however great, of one layer over another. This means that, if t

10、he fluid is at rest, no shear force (that is a force tangential to the surface on which it acts) can exist in it.</p><p>　　Fluid may be classified as Newtonian or non--Newtonian. In Newtonian fluid there is

11、a linear relation between the magnitude of applied shear stresses and the resulting rate of angular deformation. In non—Newtonian fluid there is a nonlinear relation between the magnitude of applied shear stress and the

12、rate of angular deformation.</p><p>　　The flow of fluids may be classified in many ways, such as steady or non steady, rotational or irrotational, compressible or incompressible, and viscous or no viscous.&l

13、t;/p><p>　　All hydraulic systems depend on Pascal’s law, such as steady or pipeexerts equal force on all of the surfaces of the container.</p><p>　　In actual hydraulic systems, Pascal’s law defines

14、 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, p

15、ressing on the liquid in the reservoir, forces the liquid into the pump. When the pump operates, it forces liquid from the tank into the discharge pipe at a suitable pressure.</p><p>　　The flow of the pressu

16、rized 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）control of the liquid flow rate, and (3) control of the dire

17、ction of flow of the liquid.</p><p>　　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

18、 speed in required; (3) a very compact unit is 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.</p>

19、<p>　　Fig. 1 gives a diagrammatic presentation of the components of a hydraulic installation. Electrically driven oil pressure pumps establish an oil flow for energy transmission, which is fed to hydraulic motors o

20、r 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

21、comparatively low, and therefore the term hydrostatic driver is sometime</p><p>　　The application of hydraulic power to the operation of machine tools is by no means new, though its adoption on such a wide s

22、cale as exists at present is comparatively recent. It was in fact in development of the modern self-contained pump unit that stimulated the growth of this form of machine tool operation.</p><p>　　Hydraulic m

23、achine 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 spe

24、ed. As in many other types of machine, many complex mechanical linkages can be simplified or even wholly eliminated by the use of hydraulics.</p><p>　　The flexibility and resilience of hydraulic power is ano

25、ther great virtue of this form of drive. Apart from the smoothness of operation thus obtained, a great improvement is usually found in the surface finish on the work and the tool can make heavier cuts without detriment a

26、nd will last considerably longer without regrinding.</p><p>　　Hydraulic and pneumatic system </p><p>　　There are only three basic methods of transmitting power:electrical,mechanical,and fluid po

27、wer.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

28、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 e</p><p>　　Hydrauli

29、c power transmission system are concerned with the generation, modelation, and control of pressure and flow，and in general such systems include:</p><p>　　Pumps which convert available power from the prime mo

30、ver to hydraulic power at the actuator.</p><p>　　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

31、controlling both the flow and pressure level.</p><p>　　Actcators which convert hydtaulic power to usable mechanical power output at the point required.</p><p>　　The medium, which is a liquid, pr

32、ovides rigid transmission and control as well as lubrication of componts, sealing in valves, and cooling of the system.</p><p>　　Conncetots which link the various system components, provide power conductors

33、for the fluid under pressure, and fluid flow return to tank(reservoir).</p><p>　　Fluid storage and conditioning equipment which ensure sufficient quality and quantity as well as cooling of the fluid.</p&g

34、t;<p>　　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 explorat

35、ion, 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.</p><p

36、>　　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

37、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 electromangnet is limited by

38、the saturation limit of steel. On the other hand, the power limit </p><p>　　Industry is going to depend more and more on automation in order to increase productivity. This includes remote and direct control

39、of production operations, manufacturing processes, and materials handling. Fluid power is the muscle of automation because of advantages in the following four major categories.</p><p>　　Ease and accuracy of

40、control. By the use of simple levers 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 prec

41、ise as one ten-thousandth of an inch. </p><p>　　Multiplication of force. A fluid power system(without using cumbersome gears, pulleys, and levers) can multiply forces simply and efficiently from a fraction o

42、f an ounce to several hundred tons of output.</p><p>　　Constant force or torque. Only fluid power systems are capable of providing contant force or torque regardless of speed changes. This is accomplished wh

43、ether 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.</p><p>　　Simplicity, safely, economy. In general, flu

44、id 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, companctness, and reliability. For example, a new

45、 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. Be

46、cause the steeri</p><p>　　Additonal benefits of fluid power systems include instantly reversible motion, automatic protection against overloads, and infinitely variable speed control. Fluid power systems als

47、o 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 ha

48、ve some drawbacks. Hydraulic oils are messy, and leakage is impossible to completely eliminate. Als</p><p>　　Peumatic System</p><p>　　Pneumatic systems use pressurized gases to tansmit and contr

49、ol power. A s the name implies, pneumatic systems typically use air(rather than some other gas) as the fluid medium because air is a safe, low-cost, and readily available fluid. It is particularly safe in environments wh

50、ere an electrical spark could ignite leaks from system components.</p><p>　　In pneumatic systems ,compressors are used to compress and supply the necessary quantities of air. Compressors are typically of the

51、 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 c

52、onsidered to be an infinite air source similar to an electrical system where you merely plug into an electrical outlut for electricity. In this way, </p><p>　　Free air from the atmosphere contains varying am

53、ounts 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

54、 pneumatics systems exhaust directly into 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

55、 personnel f</p><p>　　There are 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 w

56、eight of oil is a potential problem when accelerating and decelerating actuators and when suddenly opening and closing valves. Due to Newton’s law of motion(force equals mass multiplied by acceleration), the force requir

57、ed to accelerate oil is many times greater than that required to accelerate an equal volume of </p><p>　　However, because of the compressibility of air, it is impossible to obtain precise controlled actuator

58、 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), hydraulic pressures can be as hig

59、h 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 a</p><p><b>　　液壓系統(tǒng)和氣壓系統(tǒng)&

60、lt;/b></p><p><b>　　萬(wàn)輝雄，范軍</b></p><p>　　摘要：液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，例如沖壓、鋼類工件的磨削及一般加工業(yè)、農(nóng)業(yè)、礦業(yè)、航天技術(shù)、深?？碧?、運(yùn)輸、海洋技術(shù)，近海天然氣和石油勘探等行業(yè)，簡(jiǎn)而言之，在日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)成功而又廣泛使用的秘密在于它的通用性和易操作性。液壓動(dòng)力傳遞不會(huì)像機(jī)械

61、系統(tǒng)那樣受到機(jī)器幾何形體的制約，另外，液壓系統(tǒng)不會(huì)像電氣系統(tǒng)那樣受到材料物理性能的制約，它對(duì)傳遞功率幾乎沒有量的限制。</p><p>　　關(guān)鍵詞：液壓系統(tǒng)，氣壓系統(tǒng)，流體</p><p><b>　　流體和液壓系統(tǒng)</b></p><p>　　水力的歷史由來已久，始于人類為利用它周圍的能源而做出的努力。容易利用的能源就是水和風(fēng)——兩種自由的流

62、動(dòng)流體。</p><p>　　第一臺(tái)液力裝置水車是最早的發(fā)明。從15世紀(jì)早期，水車圖畫就出現(xiàn)在大宮殿的馬賽克上。磨粉機(jī)由羅馬人發(fā)明，而水磨機(jī)的歷史更早，可以追溯到大約公元前100年。當(dāng)一些上進(jìn)的農(nóng)場(chǎng)主厭惡由手工沖擊、研磨谷物時(shí)，谷物的家庭養(yǎng)殖已開始5000多年。也許，真正的發(fā)明家是那些農(nóng)場(chǎng)主的妻子，因?yàn)樗齻兘?jīng)常要干重的農(nóng)活。</p><p>　　流體是可以流動(dòng)的物體，與就是說，構(gòu)成物質(zhì)的粒

63、子可以連續(xù)地改變它們之間的相對(duì)位置，而且，它提供流體層間流動(dòng)非連續(xù)的阻力。這意味著流體在靜止時(shí)，在其內(nèi)部沒有剪切力（作用表面切向方向的受力）存在。</p><p>　　流體可以分為牛頓流體或非牛頓流體。在牛頓流體中，流體層間作用的剪切力和角度變形總量的大小成線性關(guān)系。在非牛頓流體中，流體層間作用的剪切力和角度變形總量的大小成非線性關(guān)系。</p><p>　　流體的流動(dòng)可按多種方式分類，如定

64、?；蚍嵌ǔＡ鳌⒂行骰驘o(wú)旋流、可壓縮或不可壓縮流以及黏性流或無(wú)黏性流。</p><p>　　所有的液壓系統(tǒng)遵守與帕斯卡定律，命名是由帕斯卡而來的，是他發(fā)明了此定律。這條定律指出在密封容積內(nèi)壓縮的液體——例如圓柱筒或管子——在容積的各個(gè)不同面上作用著相等的力。</p><p>　　在實(shí)際液壓系統(tǒng)中，帕斯卡定律是解釋從系統(tǒng)中獲得的各種結(jié)果的基礎(chǔ)。因此，泵使液體在系統(tǒng)中流動(dòng)，泵的進(jìn)口連接液流源，

65、經(jīng)常叫油槽或油箱。作用在油箱液面上的氣壓使流體進(jìn)入油泵。當(dāng)油泵工作是，在適當(dāng)?shù)膲毫ψ饔孟拢捅闷仁沽黧w從油箱流動(dòng)到出口。</p><p>　　由油泵泵出的壓縮液體通過各種閥門來控制。在大多數(shù)液壓系統(tǒng)中采用3種控制功能：（1）液體壓力的控制（2）液體流速的控制（3）液體流動(dòng)方向的控制</p><p>　　當(dāng)處于下列幾種情況時(shí)，液壓驅(qū)動(dòng)被優(yōu)先使用，（1）對(duì)于鏈傳動(dòng)和皮帶傳動(dòng)來說，功率的傳遞位置

66、太遠(yuǎn)：（2）低速高轉(zhuǎn)矩的場(chǎng)合（3）很緊湊的結(jié)構(gòu)（4）要求傳動(dòng)平穩(wěn)、避免振動(dòng)的場(chǎng)合（5）速度和方向容易調(diào)節(jié)的場(chǎng)合（6）輸出速度無(wú)級(jí)可調(diào)的情況。</p><p>　　由電氣驅(qū)動(dòng)的油泵供有傳遞能量的油量，并可傳遞給液壓電動(dòng)機(jī)或油缸，從而將液壓能轉(zhuǎn)換成機(jī)械能。通過閥門控制油的流動(dòng)，壓力油流產(chǎn)生線性的或旋轉(zhuǎn)的機(jī)械運(yùn)動(dòng)。油流的動(dòng)能相對(duì)比較低，因此有時(shí)采用靜壓傳動(dòng)。液壓電動(dòng)機(jī)和液壓油缸之間幾乎不存在構(gòu)造上的不同。任一油泵可以被

67、用作液壓電動(dòng)機(jī)。在任一時(shí)間里的油流量可以通過調(diào)節(jié)閥門或采用變量泵來改變。</p><p>　　液壓傳動(dòng)運(yùn)用到機(jī)床的運(yùn)行中絕不是新的，雖說現(xiàn)在的大規(guī)模采用出現(xiàn)不久?，F(xiàn)代油泵的發(fā)展促進(jìn)了這類機(jī)床的增多。</p><p>　　機(jī)床的液壓驅(qū)動(dòng)具有許多優(yōu)點(diǎn)。其中一個(gè)是液壓驅(qū)動(dòng)在廣泛的范圍內(nèi)提供無(wú)限變化的速度。另外，它們能像改變速度一樣容易來改變驅(qū)動(dòng)的方向。像許多其他類型的機(jī)床一樣，許多復(fù)雜的機(jī)械裝置

68、能夠被簡(jiǎn)單化或者由于液壓驅(qū)動(dòng)的使用完全取消。</p><p>　　液壓驅(qū)動(dòng)的另一個(gè)優(yōu)點(diǎn)是它的柔性和緩沖性。除了運(yùn)行平穩(wěn)外，還發(fā)現(xiàn)了許多改進(jìn)，如工件表面光潔度的改善，在不損壞刀具的前提下能加大刀具的負(fù)荷，并能在刃磨刀具的情況下工作更長(zhǎng)時(shí)間。</p><p><b>　　液壓與氣壓系統(tǒng)</b></p><p>　　僅有以下三種基本方法傳遞動(dòng)力：電氣

69、、機(jī)械和物流。大多數(shù)應(yīng)用系統(tǒng)實(shí)際上是將三種方法組合起來而得到最有效的最全面的系統(tǒng)。為了合理地確定采取哪些方法，重要的是了解各種方法的顯著特征。例如液壓系統(tǒng)在長(zhǎng)距離上比機(jī)械系統(tǒng)更能經(jīng)濟(jì)地傳遞動(dòng)力。然而液壓系統(tǒng)與電氣相比，傳遞動(dòng)力的距離較短。</p><p>　　液壓動(dòng)力傳遞系統(tǒng)涉及電動(dòng)機(jī)、調(diào)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(dòng)機(jī)的能力轉(zhuǎn)換成作用在執(zhí)行部件上的液壓能。閥：控制泵產(chǎn)生流體的運(yùn)動(dòng)方向、

70、產(chǎn)生的功率的大小，以及到達(dá)執(zhí)行部件液體的流量。功率大小取決于對(duì)流量和壓力大小的控制。</p><p>　　執(zhí)行部件：將液壓能轉(zhuǎn)換成可用的機(jī)械能。</p><p>　　介質(zhì)即油液：可進(jìn)行無(wú)壓縮傳遞和控制，同時(shí)可以潤(rùn)滑部件，使閥體密封和系統(tǒng)冷卻。</p><p>　　聯(lián)接件：聯(lián)接各個(gè)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。油液儲(chǔ)存和調(diào)節(jié)裝置：用來確保提供足

71、夠質(zhì)量和數(shù)量并冷卻的液體。</p><p>　　液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，例如沖壓、鋼類工件的磨削及一般加工業(yè)、農(nóng)業(yè)、礦業(yè)、航天技術(shù)、深海勘探、運(yùn)輸、海洋技術(shù)，近海天然氣和石油勘探等行業(yè)，簡(jiǎn)而言之，在日常生活中很少有人不從液壓技術(shù)得到某些益處。</p><p>　　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操作性。液壓動(dòng)力傳遞不會(huì)像機(jī)械系統(tǒng)那樣受到機(jī)器幾何形體的制約，另外，液壓系統(tǒng)不

72、會(huì)像電氣系統(tǒng)那樣受到材料物理性能的制約，它對(duì)傳遞功率幾乎沒有量的限制。例如，一個(gè)電磁體的性能受到鋼的磁炮和極限的限制，相反，液壓系統(tǒng)的功率僅僅受材料強(qiáng)度的限制。</p><p>　　企業(yè)為了提高生產(chǎn)率將越來越依靠自動(dòng)化，這包括遠(yuǎn)程和直接控制生產(chǎn)操作、加工過程和材料處理等。液壓動(dòng)力之所以成為自動(dòng)化的重要組成部分，是因?yàn)橛腥缦轮饕乃姆N優(yōu)點(diǎn)：</p><p>　　控制方便精確通過操作一個(gè)簡(jiǎn)單的

73、操縱桿和按鈕，液壓系統(tǒng)的操作者便 能立即起動(dòng)、停止、加減速和能提供任意功率、位置精確為萬(wàn)分之一英 寸的位置控制力。</p><p>　　増力一個(gè)液壓系統(tǒng)（沒有使用笨重的齒輪、滑輪和杠桿）能簡(jiǎn)單有效地將不到一盎司的力放到長(zhǎng)生幾百噸力的輸出。</p><p>　　恒力或橫扭矩 只有液壓系統(tǒng)能提供不到速度變化而變化的恒力或橫扭矩，它可以驅(qū)動(dòng)對(duì)象從每小時(shí)移動(dòng)幾

74、英寸到每分鐘幾百英寸，從每小時(shí)幾轉(zhuǎn)到每分鐘幾千轉(zhuǎn)。</p><p>　　簡(jiǎn)單、安全、經(jīng)濟(jì)總的來說，液壓系統(tǒng)比機(jī)械或電氣系統(tǒng)使用更少的運(yùn)動(dòng)部件，因此，它們運(yùn)行與維護(hù)簡(jiǎn)單。它使得系統(tǒng)結(jié)構(gòu)緊湊，安全可靠。例如一種用于車輛上的新型動(dòng)力轉(zhuǎn)向控制裝置已淘汰其他類型的轉(zhuǎn)向動(dòng)力裝置，該轉(zhuǎn)向部件中包含有人力操縱方向控制閥和分配器。因?yàn)檗D(zhuǎn)向部件是全液壓的，沒有萬(wàn)向節(jié)、軸承、減速齒輪等機(jī)械連接，這使得系統(tǒng)簡(jiǎn)單緊湊。</p>

75、<p>　　另外，只需輸入很小的扭矩就能產(chǎn)生滿足及惡劣工作條件所需的控制力，這對(duì)于因操作空間限制而需要很小方向盤的場(chǎng)合很重要，這也是減輕司機(jī)疲勞度所必需的。</p><p>　　液壓系統(tǒng)的其他優(yōu)點(diǎn)包括雙向運(yùn)動(dòng)、過載保護(hù)和無(wú)級(jí)變速控制，在已有的任何動(dòng)力系統(tǒng)中液壓系統(tǒng)具有最大的單位質(zhì)量功率比。</p><p>　　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(dòng)力傳遞問題的靈丹

76、妙藥。液壓系統(tǒng)也有些缺點(diǎn)，液壓油又污染，比且泄流不可能完全避免，另外如果油液滲漏發(fā)生在灼熱設(shè)備附近，大多數(shù)液壓油能引起火災(zāi)。</p><p><b>　　氣壓系統(tǒng)</b></p><p>　　氣壓系統(tǒng)是用壓力氣體傳遞和控制動(dòng)力，正如名稱所表明的那樣，氣壓系統(tǒng)通常用空氣（不用其他氣體）作為樓梯介質(zhì)，因?yàn)榭諝馐前踩?、成本低而又隨處可得的流體，在系統(tǒng)部件中產(chǎn)生電弧又可能點(diǎn)燃

77、泄漏物的場(chǎng)合下（使用空氣作為介質(zhì)）尤其安全。</p><p>　　在氣壓系統(tǒng)中，壓縮機(jī)用來壓縮并提供所需的孔子。壓縮機(jī)一般又活塞式、葉片式和螺旋式等類型。壓縮機(jī)基本上是根據(jù)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)通常考慮采用大的中央空氣壓縮機(jī)作為一個(gè)無(wú)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或得電能。用這種方法，壓力氣體可以從氣源輸送到整個(gè)工廠的各個(gè)角落，壓力氣體可通過空氣濾清器出去污

78、物，這些污物可能會(huì)損壞氣動(dòng)組件的精密配合部件如閥和氣缸等，隨后輸送到各個(gè)回路中，接著空氣流經(jīng)減壓閥以減少氣壓值適合某一回路使用。因?yàn)榭諝獠皇呛玫臐?rùn)滑劑（包括20%的氧氣），氣壓系統(tǒng)需要一個(gè)油霧器將細(xì)小的油霧注射到經(jīng)過減壓閥減壓的空氣中，這有助于減少氣動(dòng)組件精密配合運(yùn)動(dòng)件的磨損。</p><p>　　由于來自大氣的空氣含有不同數(shù)量的水分，這些水分是有害的，它可以帶走潤(rùn)滑劑引起過分磨損和腐蝕，因此，在一些試用場(chǎng)合中，

79、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(huì)產(chǎn)生大噪聲，因此可在氣閥和執(zhí)行組件排氣口安裝消聲器來降低噪聲，以防止操作人員因接觸噪聲及高速空氣粒子又可能引發(fā)的傷害。</p><p>　　用氣動(dòng)系統(tǒng)代替液壓系統(tǒng)有以下幾條理由：液體的慣性遠(yuǎn)比氣體大，因此，在液壓系統(tǒng)中，當(dāng)執(zhí)行組件加速減速和閥突然開啟關(guān)閉時(shí)，油液的質(zhì)量便是一個(gè)潛在的問題，根據(jù)牛頓運(yùn)動(dòng)定律（力等于質(zhì)量乘以加速度），產(chǎn)生加速運(yùn)動(dòng)油液所需

80、的力要比加速同等體積空氣所需的力高出許多倍。液體比氣體具有更大的粘性，這會(huì)因?yàn)閮?nèi)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，故它們需要特殊的油箱和無(wú)泄露系統(tǒng)設(shè)計(jì)。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。</p><p>　　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(jī)局限，其系統(tǒng)壓力相當(dāng)?shù)停ǖ?/p>