1、液壓系統(tǒng)平和壓系統(tǒng)外文文件翻譯、中英文翻譯液壓系統(tǒng)平和壓系統(tǒng)外文文件翻譯、中英文翻譯11/11液壓系統(tǒng)平和壓系統(tǒng)外文文件翻譯、中英文翻譯HydraulicsystemandPeumaticSystemHui-xiongwan1,JunFan2Abstract:Hydraulicsystemiswidelyusedinindustry,suchasstamping,grindingofsteeltypeworkandgeneralprocessingindustries,agriculture,mining,spacetechnology,deepseaexploration,transport

2、ation,marinetechnology,offshoregasandoilexplorationindustries,inshort,Fewpeopleintheirdailylivesdonotgetcertainbenefitsfromthehydraulictechnology.Successfulandwidelyusedinthehydraulicsystemssecretliesinitsversatilityandeaseofmaneuverability.Hydraulicpowertransmissionmechanicalsystemsasbeingnotliketh

3、emachinegeometryconstraints,Inaddition,thehydraulicsystemdoesnotliketheelectricalsystem,asconstrainedbythephysicalpropertiesofmaterials,itpassedalmostnoamountofpowerconstraints.Keywords:Hydraulicsystem,Pressuresystem,FluidThehistoryofhydraulicpowerisalongone,datingfrommansprehistoriceffortstoharness

4、theenergyintheworldaroundhim.Theonlysourcereadilyavailablewerethewaterandthewindtwofreeandmovingstreams.Thewatermill,thefirsthydraulicmotor,wasanearlyinvention.OneispicturedonamosaticattheGreatPalaceinByzantium,datingfromtheearlyfifthcentury.ThemillhadbeenbuiltbytheRomans.Butthefirstrecordofawatermi

5、llgoesbackevenfurther,toaround100BC,andtheoriginsmayindeedhavebeenmuchearlier.Thedomesticationofgrainbegansome5000yearsbeforeandsomeenterprisingfarmerisboundtohavebecometiredofpoundingorgrindingthegrainbyhand.Perhaps,infact,theinventorweresomefarmer。thatis,itsconstituentparticlesmaycontinuouslychang

6、etheirpositionsrelativetooneanother.Moreover,itoffersnolastingresistancetothedisplacement,howevergreat,ofonelayeroveranother.Thismeansthat,ifthefluidisatrest,noshearforce(thatisaforcetangentialtothesurfaceonwhichitacts)canexistinit.Newtonianfluidthereisanonlinearrelationbetweenthemagnitudeofapplieds

7、hearstressandtherateofangular1/10deformation.Theflowoffluidsmaybeclassifiedinmanyways,suchassteadyornonsteady,rotationalorirrotational,compressibleorincompressible,andviscousornoviscous.AllhydraulicsystemsdependonPascalslaw,suchassteadyorpipeexertsequalforceonallofthesurfacesofthecontainer.Inactualh

8、ydraulicsystems,Pascalslawdefinesthebasisofresultswhichareobtainedfromthesystem.Thus,apumpmovestheliquidinthesystem.Theintakeofthepumpisconnectedtoaliquidsource,usuallycalledthetankorreservoir.Atmosphericpressure,pressingontheliquidinthereservoir,forcestheliquidintothepump.Whenthepumpoperates,itforc

9、esliquidfromthetankintothedischargepipeatasuitablepressure.Theflowofthepressurizedliquiddischargedbythepumpiscontrolledbyvalves.Threecontrolfunctionsareusedinmosthydraulicsystems:(1)controloftheliquidpressure,（2）controloftheliquidflowrate,and(3)controlofthedirectionofflowoftheliquid.Hydraulicdrivesa

10、reusedinpreferencetomechanicalsystemswhen(1)powersistobetransmittedbetweenpointtoofarapartforchainsorbelts。(2)hightorqueatlowspeedinrequired。(3)averycompactunitisneeded。(4)asmoothtransmission,freeofvibration,isrequired。(5)easycontrolofspeedanddirectionisnecessary。and(6)outputspeedisvariedsteplessly.

11、Fig.1givesadiagrammaticpresentationofthecomponentsofahydraulicinstallation.Electricallydrivenoilpressurepumpsestablishanoilflowforenergytransmission,whichisfedtohydraulicmotorsorhydrauliccylinders,convertingitintomechanicalenergy.Thecontroloftheoilflowisbymeansofvalves.Thepressurizedoilflowproducesl

12、inearorrotarymechanicalmotion.Thekineticenergyoftheoilflowiscomparativelylow,andthereforethetermhydrostaticdriverissometimesused.Thereislittleconstructionaldifferencebetweenhydraulicmotorsandpumps.Anypumpmaybeusedasamotor.Thequantityofoilflowingatanygiventimemaybevariedbymeansofregulatingvalves(assh

13、owninFig.7.1)ortheuseofvariable-deliverypumps.Theapplicationofhydraulicpowertotheoperationofmachinetoolsisbynomeansnew,thoughitsadoptiononsuchawidescaleasexistsatpresentiscomparativelyrecent.Itwasinfactindevelopmentofthemodernself-containedpumpunitthatstimulatedthegrowthofthisformofmachinetooloperat

14、ion.2/10Hydraulicmachinetooldriveoffersagreatmanyadvantages.Oneofthemisthatitcangiveinfinitely-variablespeedcontroloverwideranges.Inaddition,theycanchangethedirectionofdriveaseasilyastheycanvarythespeed.Asinmanyothertypesofmachine,manycomplexmechanicallinkagescanbesimplifiedorevenwhollyeliminatedbyt

15、heuseofhydraulics.Theflexibilityandresilienceofhydraulicpowerisanothergreatvirtueofthisformofdrive.Apartfromthesmoothnessofoperationthusobtained,agreatimprovementisusuallyfoundinthesurfacefinishontheworkandthetoolcanmakeheaviercutswithoutdetrimentandwilllastconsiderablylongerwithoutregrinding.Hydrau

16、licandpneumaticsystemThereareonlythreebasicmethodsoftransmittingpower:electrical,mechanical,andfluidpower.Mostapplicationsactuallyuseacombinationofthethreemethodstoobtainthemostefficientoverallsystem.Toproperlydeterminewhichprinciplemethodtouse,itisimportanttoknowthesalientfeaturesofeachtype.Forexam

17、ple,fluidsystemscantransmitpowermoreeconomicallyovergreaterdistancesthancanmechanicaltypes.However,fluidsystemsarerestrictedtoshorterdistancesthanareelectricalsystems.Hydraulicpowertransmissionsystemareconcernedwiththegeneration,modelation,andcontrolofpressureandflow，andingeneralsuchsystemsinclude:P

18、umpswhichconvertavailablepowerfromtheprimemovertohydraulicpowerattheactuator.Valveswhichcontrolthedirectionofpump-flow,thelevelofpowerproduced,andtheamountoffluid-flowtotheactuators.Thepowerlevelisdeterminedbycontrollingboththeflowandpressurelevel.Actcatorswhichconverthydtaulicpowertousablemechanica

19、lpoweroutputatthepointrequired.Themedium,whichisaliquid,providesrigidtransmissionandcontrolaswellaslubricationofcomponts,sealinginvalves,andcoolingofthesystem.Conncetotswhichlinkthevarioussystemcomponents,providepowerconductorsforthefluidunderpressure,andfluidflowreturntotank(reservoir).Fluidstorage

20、andconditioningequipmentwhichensuresufficientqualityandquantityaswellascoolingofthefluid.Hydraulicsystemsareusedinindustrialapplicationssuchasstampingpresses,steelmills,andgeneralmanufacturing,agriculturalmachines,miningindustry,3/10aviation,spacetechnology,deep-seaexploration,transportion,marinetec

21、hnology,andoffshoregasandpetroleumexploration.Inshort,veryfewpeoplegetthroughadayoftheirliveswithoutsomehowbenefitingfromthetechnologyofhydraulicks.Thesecretofhydraulicsystemssuccessandwidespreaduseisitsversatilityandmanageability.Fluidpowerisnothinderedbythegeometryofthemachineasisthecaseinmechanic

22、alsystems.Also,powercanbetransmittedinalmostlimitlessquantitiesbecausefluidsystemsarenotsolimitedbythephysicallimitationsofmaterialsasaretheelectricalsystems.Forexample,theperformanceofanelectromangnetislimitedbythesaturationlimitofsteel.Ontheotherhand,thepowerlimitoffluidsystemsislimitedonlybythest

23、rengthcapacityofthematerial.Industryisgoingtodependmoreandmoreonautomationinordertoincreaseproductivity.Thisincludesremoteanddirectcontrolofproductionoperations,manufacturingprocesses,andmaterialshandling.Fluidpoweristhemuscleofautomationbecauseofadvantagesinthefollowingfourmajorcategories.Easeandac

24、curacyofcontrol.Bytheuseofsimpleleversandpushbuttons,theoperatorofafluidpowersystemcanreadilystart,stop,speeduporslowdown,andpositionforceswhichprovideanydesiredhorsepowerwithtolerancesaspreciseasoneten-thousandthofaninch.Multiplicationofforce.Afluidpowersystem(withoutusingcumbersomegears,pulleys,an

25、dlevers)canmultiplyforcessimplyandefficientlyfromafractionofanouncetoseveralhundredtonsofoutput.Constantforceortorque.Onlyfluidpowersystemsarecapableofprovidingcontantforceortorqueregardlessofspeedchanges.Thisisaccomplishedwhethertheworkoutputmovesafewinchesperhour,severalhundredinchesperminute,afew

26、revolutionsperhour,orthousandsofrevolutionsperminute.Simplicity,safely,economy.Ingeneral,fluidpowersystemsusefewermovingpartsthancomparablemechanicalorelectricalsystems.Thus,theyaresimplertomaintainandoperate.This,inturn,maximizessafety,companctness,andreliability.Forexample,anewpowersteeringcontrol

27、designedhasmadeallotherkindsofpowersystemsobsoleteonmanyoff-highwayvehicles.Thesteeringunitconsistsofamanuallyoperateddirectionalcontrolvalveandmeterinasinglebody.Becausethesteeringunitisfullyfluid-linked,mechanicallinkages,universaljoints,bearings,reductiongears,etc,areeliminated.Thisprovidesasimpl

28、e,compactsystem.Inaddition,verylittleinputtorqueisrequiredtoproducethecontrolneededforthe4/10toughestapplications.Thisisimportantwherelimitationsofcontrolspacerequireasmallsteeringwheelanditbecomesnecessarytoreduceoperatotrfatique.Additonalbenefitsoffluidpowersystemsincludeinstantlyreversiblemotion,

29、automaticprotectionagainstoverloads,andinfinitelyvariablespeedcontrol.Fluidpowersystemsalsohavethehighesthorsepowerperweightratioofanyknownpowersource.Inspiteofallthesehighlydesirablefeaturesoffluidpower,itisnotapanaceaforallpowertransmissionproblems.Hydraulicsystemsalsohavesomedrawbacks.Hydraulicoi

30、lsaremessy,andleakageisimpossibletocompletelyeliminate.Also,mosthydraulicoilscancausefiresifanoilsoccursinanareaofhotequipment.PeumaticSystemPneumaticsystemsusepressurizedgasestotansmitandcontrolpower.Asthenameimplies,pneumaticsystemstypicallyuseair(ratherthansomeothergas)asthefluidmediumbecauseairi

31、sasafe,low-cost,andreadilyavailablefluid.Itisparticularlysafeinenvironmentswhereanelectricalsparkcouldigniteleaksfromsystemcomponents.（containsabout20%oxygen）,pneumaticssystemsrequiredalubricatortoinjectaveryfinemistofoilintotheairdischargingfromthepressureregulator.Thispreventswearofthecloselyfitti

32、ngmovingpartsofpneumaticcomponents.Freeairfromtheatmospherecontainsvaryingamountsofmoisure.Thismoisurecanbeharmfulinthatitcanwashawaylubricantsandthuscauseexcessivewearandcorrosion.Hence,insomeapplications,airdriersareneededtoremovethisundesirablemoisture.Sincepneumaticssystemsexhaustdirectlyintothe

33、atmosphere,theyarecapableofgeneratingexcessivenoise.Therefore,mufflersaremountedonexhaustportsofairvalvesandactuatorstoreducenoiseandpreventoperating5/10personnelfrominjuryresultingnotonlyfromexposuretonoisebutalsofromhigh-speedairborneparticles.Thereareseveralreasonsforconsideringtheuseofpneumatics

34、ystemsinsteadofhydraulicsystems.Liquidsexhibitgreaterinertiathandogases.Therefore,inhydraulicsystemstheweightofoilisapotentialproblemwhenacceleratinganddeceleratingactuatorsandwhensuddenlyopeningandclosingvalves.DuetoNewtoninlargerfrictionalpressureandpowerlosses.Also,sincehydraulicsystemsuseafluidf

35、oreigntotheatmosphere,theyrequirespecialreservoirsandnoleaksystemdesigns.Pneumaticsystemuseairwhichisexhausteddirectlybackintothesurroundingenvironment.Generallyspeaking,pneumaticsystemsarelessexpensivethanhydraulicsystems.However,becauseofthecompressibilityofair,itisimpossibletoobtainprecisecontrol

36、ledactuatorvelocitieswithpneumaticsystems.Also,precisepositioningcontrolisnotobtainable.Whilepneumaticspressuresarequitelowduetocompressordesignlimitations(lessthan250psi),hydraulicpressurescanbeashighas10000psi.Thus,hydraulicscanbehigh-powersystems,whereaspneumaticsareconfinedtolow-powerapplication

37、s.Industrialapplicationsofpneumaticssystemsaregrowingatarapidpace.Typicalexamplesincludestamping,drilling,hoist,punching,clamping,assembling,riveting,materialshandling,andlogiccontrollingoperations.液壓系統(tǒng)平和壓系統(tǒng)萬(wàn)輝雄1，范軍2大綱：液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，比方?jīng)_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，在平常生活中極

38、稀有人不從液壓技術(shù)獲得某些利處。液壓系統(tǒng)成功而又廣泛使用的奧秘在于它的通用性和易操作性。液壓動(dòng)力傳達(dá)不會(huì)像機(jī)械系統(tǒng)那樣碰到機(jī)器幾何形體的限制，其他，液壓系統(tǒng)不會(huì)像電6/10氣系統(tǒng)那樣碰到資料物理性能的限制，它對(duì)傳達(dá)功率幾乎沒有量的限制。要點(diǎn)詞：液壓系統(tǒng)，氣壓系統(tǒng)，流體流體和液壓系統(tǒng)水力的歷史由來(lái)已久，始于人類為利用它周圍的能源而做出的努力。簡(jiǎn)單利用的能源就是水細(xì)風(fēng)兩種自由的流動(dòng)流體。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，可以追想到大約公元前100年。當(dāng)一些進(jìn)步的農(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

39、開始5000多年。也許，真切的發(fā)明家是那些農(nóng)場(chǎng)主的妻子，由于她們經(jīng)常要干重的農(nóng)活。流體是可以流動(dòng)的物體，與就是說，組成物質(zhì)的粒子可以連續(xù)地改變它們之間的相對(duì)地址，而且，它供應(yīng)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。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。流體的流動(dòng)可按多種方式分類，如定?；蚍嵌ǔＡ?、有旋流或無(wú)旋流、可壓縮或不可以壓縮流以及黏性流或無(wú)黏性流。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(lái)的，

40、是他發(fā)了然此定律。這條定律指出在密封容積內(nèi)壓縮的液體比方圓柱筒或管子在容積的各個(gè)不相同面上作用著相等的力。在實(shí)質(zhì)液壓系統(tǒng)中，帕斯卡定律是講解從系統(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，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，在適合的壓力作用下，油泵迫使流體從油箱流動(dòng)到出口。由油泵泵出的壓縮液體經(jīng)過各種閥門來(lái)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)方向的控制當(dāng)處于以下幾種情況時(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(lái)說，功率的傳達(dá)地址太遠(yuǎn)：（2）低速高轉(zhuǎn)矩的場(chǎng)合（3）

41、很緊湊的構(gòu)造4）要求傳動(dòng)平穩(wěn)、防范振動(dòng)的場(chǎng)合（5）速度和方向簡(jiǎn)單一治的場(chǎng)合（6）輸出速度無(wú)級(jí)可調(diào)的情況。由電氣驅(qū)動(dòng)的油泵供有傳達(dá)能量的油量，并可傳達(dá)給液壓電動(dòng)機(jī)或油缸，7/10從而將液壓能變換成機(jī)械能。經(jīng)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)能相比較較低，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)造上的不相同。任一油泵可以被用作液壓電動(dòng)機(jī)。在任一時(shí)間里的油流量可以經(jīng)過調(diào)治閥門或采用變量泵來(lái)改變。液壓傳動(dòng)運(yùn)用到機(jī)床的運(yùn)行中絕不是新的，固然現(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)床的增加。機(jī)床的液壓驅(qū)動(dòng)擁有好多優(yōu)點(diǎn)。其中一個(gè)是液壓驅(qū)動(dòng)在廣泛的范

42、圍內(nèi)供應(yīng)無(wú)量變化的速度。其他，它們能像改變速度相同簡(jiǎn)單來(lái)改變驅(qū)動(dòng)的方向。像好多其他種類的機(jī)床相同，好多復(fù)雜的機(jī)械裝置可以被簡(jiǎn)單化也許由于液壓驅(qū)動(dòng)的使用完好取消。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)了好多改進(jìn)，如工件表面光潔度的改進(jìn)，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。液壓與氣壓系統(tǒng)僅有以下三種基本方法傳達(dá)動(dòng)力：電氣、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(lái)而獲得最有效的最全面的系統(tǒng)。為了合理地確定采用哪些方法，重要的是認(rèn)識(shí)各種方法的顯然特色。比方液壓系統(tǒng)在長(zhǎng)距離上比機(jī)械系統(tǒng)更能經(jīng)濟(jì)地傳達(dá)動(dòng)力?？墒且簤合到y(tǒng)與電氣對(duì)照，傳

43、達(dá)動(dòng)力的距離較短。液壓動(dòng)力傳達(dá)系統(tǒng)涉及電動(dòng)機(jī)、調(diào)治裝置和壓力和流量控制，總的來(lái)說，該系統(tǒng)包括：泵：將原動(dòng)機(jī)的能力變換成作用在執(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、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。執(zhí)行部件：將液壓能變換成可用的機(jī)械能。介質(zhì)即油液：可進(jìn)行無(wú)壓縮傳達(dá)和控制，同時(shí)可以潤(rùn)滑部件，使閥體密封和系統(tǒng)冷卻。聯(lián)接件：聯(lián)接各個(gè)系統(tǒng)部件，為壓力流體供應(yīng)功率傳輸通路，將液體返回油箱。油液儲(chǔ)蓄和調(diào)治裝置：用來(lái)保證供應(yīng)足夠質(zhì)量和數(shù)量并冷卻的液體。液壓系統(tǒng)在工業(yè)中應(yīng)用廣泛，比方?jīng)_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)

44、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，在平常生活中極稀有人不從液壓技術(shù)獲得某些利處。液壓系統(tǒng)成功而又廣泛使用的奧秘在于它的通用性和易操作性。液壓動(dòng)力傳達(dá)不會(huì)像機(jī)械系統(tǒng)那樣碰到機(jī)器幾何形體的限制，其他，液壓系統(tǒng)不會(huì)像電氣系統(tǒng)那樣碰到資料物理性能的限制，它對(duì)傳達(dá)功率幾乎沒有量的限制。例8/10如，一個(gè)電磁體的性能碰到鋼的磁炮和極限的限制，相反，液壓系統(tǒng)的功率僅僅受資料強(qiáng)度的限制。企業(yè)為了提升生產(chǎn)率將越來(lái)越依靠自動(dòng)化，這包括遠(yuǎn)程和直接控制生產(chǎn)操作、加工過程和資料辦理等。液壓動(dòng)力之因此成為自動(dòng)化的重要組成部分，是由于有以下主要的四種優(yōu)點(diǎn)：控制方便精確經(jīng)過操作一個(gè)簡(jiǎn)單的控制桿和按鈕，液壓系統(tǒng)的操作者便能馬上起動(dòng)、停止、加減速和能供應(yīng)任意功率、地址精確為萬(wàn)分之一英寸的地址控制力。増力一個(gè)液壓系統(tǒng)（沒有使用粗笨的齒輪、滑輪