液壓系統(tǒng)的外文文獻(xiàn)翻

1、jingchu university of technology畢業(yè)設(shè)計(jì)（論文）外文文獻(xiàn)翻譯譯文題目 hydraulic system 專 業(yè)機(jī)械設(shè)計(jì)制造及其自動(dòng)化 班 級 09機(jī)制一班 姓 名 汪康 學(xué) 號(hào) 2009403010107 指導(dǎo)教師 王霞 機(jī)械工程學(xué)院hydraulic systemthere are only three basic methods of transmitting power：electrical，mechanicaland fluid powermost applications actually use a combination of the three

2、methods to obtain the most efficient overall systemto properly determine which principle method to use。it is important to know the salient features of each typefor example，fluid systems call transmit power more economically over greater distances than can mechanical typeshowever。fluid systems are re

3、stricted to shorter distances than are electrical systems hydraulic transmission there are many outstanding advantages, it is widely used, such as general industrial use of plastics processing machinery, the pressure of machinery, machine tools, etc.; operating machinery engineering machinery, const

4、ruction machinery, agricultural machinery, automobiles, etc.; iron and steel industry metallurgical machinery, lifting equipment, such as roller adjustment device; civil water projects with flood control and dam gate devices, bed lifts installations, bridges and other manipulation of institutions; s

5、peed turbine power plant installations, nuclear power plants, etc.; ship from the deck heavy machinery (winch), the bow doors, bulkhead valve, stern thruster, etc.; special antenna technology giant with control devices, measurement buoys, movements such as rotating stage; military-industrial control

6、 devices used in artillery, ship anti- rolling devices, aircraft simulation, aircraft retractable landing gear and rudder control devices and other devices.the role of the hydraulic system to increase the force by changing the pressure. a hydraulic system is good or bad depends on the system design

7、is reasonable, the merits of the performance system components, system, pollution prevention and treatment, while the last point is particularly important. in recent years, chinas domestic hydraulic technology has greatly improved, not simply using hydraulic technology from abroad for processing. a

8、complete hydraulic system consists of five parts, namely, power components, the implementation of components, control components, auxiliary components (annex) and the hydraulic oil. the role of dynamic components is the original motivation of the mechanical energy into fluid pressure energy, the hyd

9、raulic system of pumps, which provide power to the entire hydraulic system. structures of hydraulic pumps generally have gear pumps, vane pumps and piston pumps.implementation of components (such as hydraulic cylinders and hydraulic motors) is to pressure the liquid can be converted to mechanical en

10、ergy to drive the load for a linear reciprocating movement or rotational movement.control components in the hydraulic system control and regulation of fluid pressure, flow and direction. according to the different control functions, hydraulic valves can be divided into pressure control valves, flow

11、control valves and directional control valve. pressure control valve is divided into benefits flow valve (safety valve), pressure relief valve, sequence valve, pressure switch, etc.; flow control valves including throttle, adjusting valves, flow diversion valve assembly; directional control valve in

12、cludes a check valve, check valve, shuttle valve, valve and so on. under the control of different ways, hydraulic valves can be divided into switching control valves, control valves and the fixed value proportional control valve. auxiliary components, including fuel tanks, filters, tubing and pipe j

13、oints, seals, quick couplings, high pressure ball valve, hose assembly, pressure fittings, pressure gauge, oil level, oil temperature meter and so on. hydraulic system of hydraulic oil is the work of the energy transfer medium, a variety of mineral oil, emulsion, oil hydraulic molding hop categories

14、the role of the hydraulic system is to help humanity work. mainly by the implementation of components to rotate or pressure into a reciprocating motion. hydraulic principle ：it consists of two cylinders of different sizes and composition of fluid in the fluid full of water or oil. water is called hy

15、draulic press; the said oil filled hydraulic machine. each of the two liquid a sliding piston, if the increase in the small piston on the pressure of a certain value, according to pascals law, small piston to the pressure of the pressure through the liquid passed to the large piston, piston top will

16、 go a long way to go. based cross-sectional area of the small piston is s1, plus a small piston in the downward pressure on the f1. thus, a small piston on the liquid pressure to p = f1/si, can be the same size in all directions to the transmission of liquid. by the large piston is also equivalent t

17、o the inevitable pressure p. if the large piston is the cross-sectional area s2, the pressure p on the piston in the upward pressure generated f2 = pxs2 cross-sectional area is a small multiple of the piston cross-sectional area. from the type known to add in a small piston of a smaller force, the p

18、iston will be in great force, for which the hydraulic machine used to suppress plywood, oil, extract heavy objects, such as forging steel.the secret of hydraulic systems success and widespread use is its versatility and manageabilityfluid power is not hindered by the geometry operations when the pot

19、ential difference between the tool and the work piece is sufficiently high, a transient spark discharges through the fluid, removing a very small amount of metal from the work piece of the machine as is the ease in mechanical systemsalso，power can be transmitted in almost limitless quantities becaus

20、e fluid systems are not so limited by the physical 1imitations of materials as are the electrical systemsfor example，the performance of an electromagnet is limited by the saturation limit of steelon the other hand，the power limit of fluid systems is 1imited only by the strength capacity of the mater

21、ialindustry is going to depend more and more on automation in order to increase productivitythis includes remote and direct control of production operations，manufacturing processes。and materials handlingfluid power is the muscle of automation because of advantages in the following four major categor

22、ies1 the precise convenient control by operating a simple joystick and buttons, the operators of the hydraulic system and can immediately start, stop, and deceleration and can provide any power, position precision for one over ten thousand inch position control. a make the pilot rises and fall the l

23、anding gear on the hydraulic system, when the pilot to a certain direction control valves, pressure oil into hydraulic cylinder of a cavity and came down on the landing gear. the pilot to move in the opposite direction control valves, allow the oil into the hydraulic cylinder of another chamber to t

24、ake back on the landing gear. 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 output3 constant force or torqueonly fluid power systems are capable of pro

25、viding constant force or torque regardless of speed changesthis is accomplished whether the work output moves a few inches per hour，several hundred inches per minute，a few revolutions per houror thousands of revolutions per minute4 simplicity，safety，economygeneral，fluid power systems use fewer movin

26、g parts than comparable mechanical or electrical systemsthus，they ale simpler to maintain and operatethis，in turn，maximizes safety，compactness，and reliabilityfor example，a new power steering control designed has made all other kinds of power systems obsolete on many offhighway vehiclesthe steering u

27、nit consists of a manually operated directional control valve and meter in a single bodytransportation，marine technology，and offshore gas and petroleum explorationin addition，very little input torque is required to produce the control needed for the toughest applicationsthis is important where 1imit

28、ations of control space require a small steering wheel and it becomes necessary to reduce operator fatigueadditional benefits of fluid power systems include instantly reversible motion。automaticprotection against overloads，and infinitely variable speed controlfluid power systems also have the highes

29、t horsepower per weight ratio of any known power sourcethe three hydraulic system diseases.1 as result of heat transmission 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 p

30、ipelines at the same time there is friction between the inner wall, which are a result of hydraulic the reasons for the oil temperature. temperature will lead to increased internal and external leakage, reducing its mechanical efficiency. at the same time as a result of high temperature, hydraulic o

31、il expansion will occur, resulting in increased compression, so that action can not be very good control of transmission. solution: heat is the inherent characteristics of the hydraulic system, not only to minimize eradication. use good quality hydraulic oil, hydraulic piping arrangement should be a

32、voided as far as possible the emergence of bend, the use of high-quality pipe and fittings, hydraulic valves, etc.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

33、the closure of the 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 failures. solutions: hydraulic pipe should be fixed to avoid

34、sharp bends. to avoid frequent changes in flow direction, can not avoid damping measures should be doing a good job. the entire hydraulic system should have good damping measures, while avoiding the external local oscillator on the system.3 the leakage of the hydraulic system leak into inside and ou

35、tside the leakage. leakage refers to the process with 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 hydraulic fluid loss, but due to leakage, the co

36、ntrol of the established movements may be affected until the cause system failures. outside means the occurrence of leakage in the system and the leakage between the external environments. direct leakage of hydraulic oil into the environment, in addition to the system will affect the working environ

37、ment, not enough pressure will cause the system to trigger a fault. leakage into the environment of the hydraulic oil was also the danger of fire. solution: the use of better quality seals to improve the machining accuracy of equipment.in the hydraulic system and its system，the sealing device to pre

38、vent 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 will result in leakage of waste, pollution and environmental machinery and even give rise to malfunctioning machinery and equipment for persona

39、l accident. leakage within the hydraulic system will cause a sharp drop in volumetric efficiency, amounting to less than the required pressure, can not even work. micro-invasive system of dust particles can cause or exacerbate friction hydraulic component wear, and further lead to leakage.therefore,

40、 seals and sealing device is an important hydraulic equipment component. the reliability of its work and life is a measure of the 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 th

41、e need to control the liquid can be sealed following the smallest gap. in the contact seal, pressed into self-seal-style and self-styled self-tight seal (is, sealed lips) two. 液壓系統(tǒng)一般僅有以下三種基本方法傳遞動(dòng)力：電氣、機(jī)械和液壓。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(jī)械系統(tǒng)更能經(jīng)濟(jì)地傳遞動(dòng)力。然而液壓

42、系統(tǒng)與電氣系相比，傳遞動(dòng)力的距離較短。液壓傳動(dòng)有許多突出的優(yōu)點(diǎn)，它被廣泛的應(yīng)用，如一般工業(yè)用的塑料加工機(jī)械，壓力機(jī)械，機(jī)床等；應(yīng)用機(jī)械設(shè)備工程機(jī)械，建筑機(jī)械，農(nóng)業(yè)機(jī)械，汽車等；鋼鐵行業(yè)的冶金機(jī)械，起重機(jī)械，還有軋輥調(diào)整裝置等；水利工程中的控制閘門裝置，河床升降裝置，橋梁和其他操作機(jī)構(gòu)；發(fā)電廠高速渦輪裝置，核電站等；船舶甲板用的起重機(jī)械（絞車），船頭門，艙壁閥、船尾推進(jìn)器等；特殊技術(shù)用的巨型天線控制裝置、測量浮標(biāo)、升降旋轉(zhuǎn)舞臺(tái)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(jī)起落架的收放裝置和方向舵控制裝置等。特殊技術(shù)的天線控制裝置，測量浮標(biāo)，升降旋轉(zhuǎn)舞臺(tái)；軍用的火炮操縱裝置，船舶減搖

43、裝置，飛行器仿真，飛機(jī)起落架收放裝置和方向舵控制裝置和其他設(shè)備。液壓系統(tǒng)的作用為通過改變壓強(qiáng)增大作用力。一個(gè)液壓系統(tǒng)的好壞取決于系統(tǒng)設(shè)計(jì)的合理性、系統(tǒng)元件性能的優(yōu)劣，系統(tǒng)的污染防護(hù)和處理，而最后一點(diǎn)尤為重要。近年來我國國內(nèi)液壓技術(shù)有很大的提高，不再單純地使用國外的液壓技術(shù)進(jìn)行加工。一個(gè)完整的液壓系統(tǒng)由五個(gè)部分組成，即動(dòng)力元件、執(zhí)行元件、控制元件、輔助元件（附件）和液壓油。動(dòng)力元件的作用是將原動(dòng)機(jī)的機(jī)械能轉(zhuǎn)換成液體的壓力能，指液壓系統(tǒng)中的油泵，它向整個(gè)液壓系統(tǒng)提供動(dòng)力。液壓泵的結(jié)構(gòu)形式一般有齒輪泵、葉片泵和柱塞泵。執(zhí)行元件(如液壓缸和液壓馬達(dá))的作用是將液體的壓力能轉(zhuǎn)換為機(jī)械能，驅(qū)動(dòng)負(fù)載作直線往

44、復(fù)運(yùn)動(dòng)或回轉(zhuǎn)運(yùn)動(dòng)?？刂圃?即各種液壓閥)在液壓系統(tǒng)中控制和調(diào)節(jié)液體的壓力、流量和方向。根據(jù)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(diào)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(jù)控制方式不同，液壓閥可分為開關(guān)式控制閥、定值控制閥和比例控制閥。輔助元件包括油箱、濾油器、油管及管接頭、密封圈、快換接頭、高壓球閥、膠管總成、測壓接頭、壓力表、油位油溫計(jì)等。液壓油是液壓系統(tǒng)中傳遞能量的工作介質(zhì)，有各種礦物油、乳化液和合成型液壓油等幾大類。液壓系統(tǒng)的作用是幫助人類工

45、作，主要通過執(zhí)行元件將壓力轉(zhuǎn)換為旋轉(zhuǎn)或往復(fù)運(yùn)動(dòng)。液壓原理：它由兩個(gè)不同大小的缸體充滿了水或油。充滿水的稱為“水壓機(jī)”，充滿油的稱為“液壓機(jī)”。兩個(gè)液缸每個(gè)都有一個(gè)可動(dòng)的活塞，如果在小活塞上加點(diǎn)壓力，根據(jù)帕斯卡定律，小活塞的壓力通過液體的壓力傳遞到大活塞，頂端的活塞將前進(jìn)很長的距離?；拘』钊臋M截面積為s1，外加一個(gè)小活塞上一個(gè)向下的力f1。因此，小活塞對液體的壓強(qiáng)p=f1/s1的，可以在所有方向上傳輸同樣大小。通過大活塞的壓力也為p。如果大活塞的橫截面積為s2，活塞的壓強(qiáng)p向上的壓力f2=p*s2，橫截面積是小活塞的幾倍，加給小活塞小的力，活塞會(huì)有大的壓力，由此用液壓機(jī)壓制膠合板，油，提起重物，鍛造煉鋼。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)不會(huì)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(gè)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(qiáng)度的限制。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