機(jī)電工程專業(yè)英語

1Therotor(rotatingmember)inanelectricmotorhasrotationalinertia,andatorqueisrequiredtobringituptospeedwhenthemotorisstarted.Ifthemotorshaftisrigidlyconnectedtoaloadwithalargerotationalinertia,andthemotorisstartedsuddenlybyclosingaswitch,themotormaynothavesufficienttorquecapacitytobringthemotorshaftupspeedbeforethewindingsinthemotorareburnedoutbytheexcessivecurrentdemands.Aclutchbetweenthemotorandtheloadshaftswillrestrictthestartingtorqueonthemotortothatrequiredtoacceleratetherotorandpartsoftheclutchonly.電機(jī)的轉(zhuǎn)子（轉(zhuǎn)動(dòng)元件之一）2Tokeepthepartsseparated,itisnecessarythatthepressurewithinthelubricationfilmbalancetheloadontheslidingsurfaces.Ifthelubricatingfilm’spressureissuppliedbyanexternalsource,thesystemissaidtobelubricatedhydro-statically.Ifthepressurebetweensurfacesisgeneratedasaresultoftheshapeandmotionofthesurfacesthemselves,however,thesystemishydro-dynamicallylubricated.Thissecondtypeoflubricationdependsupontheviscouspropertiesofthelubricant.（荷稱為流體動(dòng)壓潤滑。第二種潤滑與潤滑劑的粘性密切相關(guān)。3Thematerialmustresistdeformationandfracture.Hardnessmustbebalancedagainstelasticity.Theframemustwithstandimpact,yetunderloadwithoutcrackingorpermanentlydeforming.Theframematerialmusteliminateorblockvibrationtransmissiontoreduceoscillationsthatdegradeaccuracyandtoollife.Itmustwithstandthehostileshop-floorenvironment,includingthenewercoolantsandlubricants.Materialexpansionmustbeunderstood(inorder)tominimizeforcesneededtomoveslides.Thematerialmustnotbuilduptoomuchheat,mustretainitsshapeforitslifetime,andmustbedenseenoughtodistributeforcesthroughoutthemachine.4Athreadedfastenerisadevicethatcaneffectivelyexertandalargeforceinonedirection(axially)throughtheapplicationofasmallforceinanotherdirection(tangentially).Allarebasedonthesinglethreadedscrew,asimplemachinethatyieldsalargemechanicaladvantageinminimalspaceandtheoreticallyisselflocking.Effectiveusehowever,requirestheaidoftwoothersimplemachines:theleverandwheel-and-axelmachine.Thewrenchisbasicallyalever,thescrewdriverisawheel-and-axlemachine.（軸向通過（切向螺絲刀是一個(gè)軸機(jī)。5Agroupofmaterialswhichappearspromisingforultra-hightemperaturebearingoperationishighperformanceceramics.Attemperaturesabove1100ctheseceramicmaterialshaveahigherhardnessthannormalbearingsteels.Forthepastdecadeoneceramicmaterialhasbeendevelopedtothevirtualexclusionofallothersforhighspeed,hightemperaturerollingbearings:hotpressedorhotisostatically pressedsiliconnitride(Si3N4).Siliconnitrideisdesirablebecauseithasgoodtemperaturestrengthandhardness,anadvantageousstrengthrelationshipandexcellentresistancetorollingcontactfatiguewhenthereisadequatelubrication.有希望用于高溫軸承的材料是高性能的陶瓷系列。在溫度高于1100的高溫強(qiáng)度和硬度，理想的強(qiáng)度/重量關(guān)系，并且當(dāng)潤滑充分時(shí)，它具有優(yōu)異的滾動(dòng)接觸疲勞強(qiáng)度。6Three-dimensionalgeometricmodelinginvolveswireframe,surface,andsolidmodels.Awireframemodelshowsaseriesofnodesconnectedbylinestoformanobject.Asurfacemodelcompletelydefinesaseriesofconnectedtoformtheboundaryofanobject.Thesolidmodelisadefinitionofanobjectwhichincludesknowledgeofallboundaryandinternalpoints.Fromasolidmodel,acompleteanalysisofperformanceoftheobjectcanbeperformedonthecomputerwithappropriatesoftware.7Engineeringdesignisasystematicprogressbywhichsolutionstotheneedsofhumankindareobtained.Theprogressisappliedtoproblems(needs)ofvaryingcomplexity.Forexample,mechanicalengineerswillusethedesignprocesstofindaneffective,efficientmethodtoconvertreciprocatingmotiontocircularmotionforthedrivetraininaninternalcombustionengine;electricalengineerswillusetheprocesstoelectricalgeneratingsystemsusingfallingwaterasthepowerandmaterialsengineersusetheprocesstodesignablativematerialswhichenableastronautstosafetyreentertheearth'satmosphere.程師應(yīng)用這一設(shè)計(jì)過程研制燒蝕材料，使宇航員能安全地重返大氣層。8Engineeringdesignistheprocessofdevisingasystem,component,orprocesstomeetdesiredneeds.Itisadecisionmakingprocess(ofteniterative,inwhichthebasicsciences,mathematics,andengineeringsciencesareappliedtoconvertresourcesoptimallytomeetastatedobjective.Theengineeringdesigncomponentofacurriculummustincludemostofthefollowingfeatures:developmentofstudentcreativity,useofopen-endedproblems,developmentanduseofmoderndesigntheorymethodology,formulationofdesignproblemstatementsandspecifications,considerationofalternativesolutions,feasibilityconsiderations,productionprocesses,concurrentengineeringdesign,anddetailedsystemdescriptions.Further,itisessentialtoincludeavarietyofrealisticconstraintssuchaseconomicfactors,safety,reliability,aesthetics,ethics,andsocialimpact.（經(jīng)常需要反復(fù)9Thedesignprocessusuallybeginswithaspecificationofasolution.Wesometimesalludetoadesigncycle,buttheprocessmaycontainacycleplusdesignimplementation,whichinvolvesactualproductionbaseduponthedesign.Thedesigncyclecaninvolvetheoriginalthoughts,sketches, and knowledge that in the specification stage produceengineeringdrawings.Computer-aideddesignisnowemployedtoimplementacycleinwhichvariousdesignsordesignideasmaybetestedorsimulated.用來實(shí)現(xiàn)各種設(shè)計(jì)或設(shè)計(jì)思路的測(cè)試或仿真。10Ifaproductisimproperlymanufacturedordefectivelydesigned,awarningwillnotbesufficienttorelievethemanufacturerofresponsibility.Ifamanufacturerdiscoversadangerousdesigndefectormanufacturingdefectaftertheproducthasbeenmarketed,itgenerallyhasadutywarnthosewhohavealreadypurchasedtheproduct,Theremaybeatorecalltheproductinsomecircumstances.Themanufactureralsoadutytowarnusersofdangersresultingfromtheforeseeablebutunintendeduseormisuseoftheproduct.如果一個(gè)產(chǎn)品的生產(chǎn)不正確或設(shè)計(jì)不當(dāng),警告是不足以解除制造商的責(zé)任。如果任警告用戶由可預(yù)見但無意識(shí)的使用或產(chǎn)品的濫用造成的危險(xiǎn)。11“Iamanengineer.InmyprofessionItakedeeppride,butwithoutvain-glory;toitIowesolemnobligationsthatIameagertoAsanEngineer,Iwillparticipateinnonebuthonestenterprise.Tohimthathasengagedmyservices,asemployerorclient,Iwillgivetheutmostofperformanceandfidelity.Whenneeded,myskillandknowledgeshallbegivenwithoutreservationforthepublicgood.Fromspecialcapacityspringstheobligationtouseitwellintheserviceofhumanity;andIacceptthechallengethatthisimplies.于它我擁有莊嚴(yán)的使命,我愿意已全部的熱情去履行這一切。作為工程師,我要參入誠信的企業(yè)。他作為雇主或客戶，聘用了我的服務(wù),而我也將表現(xiàn)出我的實(shí)力和忠誠。需要時(shí),我的才能和知識(shí)將沒有保留的貢獻(xiàn)給公共利益。從特別才能所迸發(fā)出來的責(zé)任應(yīng)該更好地為人類造福，我接受那些潛在的挑戰(zhàn)。12Grindingisaprocesswithsuchabroadapplicationrangethatmanyvariationsonthesebasicdesignthemeshavebeendevelopedovertheyears,andnoattemptwillbemadetocoverthemallhereindetail.Jiggrinders,ultra-precisionbearingballgrinders,andawholespectrumofotherspecializedgrinderscouldeacheasilybethetopicofanarticlelongerthanthisone.Theprinciples,however,areessentiallyuniversalandshouldbeapplicablewithslightmodificationtovirtuallyanyapplicationyoumayhave.文章都比這更長。而原理基本上是一樣的，幾乎所有磨削加工余量都很小。13Multiple-spindleautomaticscrewmachineshavefourtoeightspindleslocatedaroundaspindlecarrier.Longbarofstock,supportedontherearofthemachine,passthroughthesehollowspindlesandaregrippedbycollets.Withthesingle-spindlemachine,theturretindexesaroundspindle.Whenonetoolontheturretisworking,theothersarenot.Withamultiple-spindlemachine,however,thespindleitselfindexes.Thusthebarsofstockarecarriedtothevariousend-workingandside-workingtools.Eachtooloperatesinonlyposition,butalltoolsoperatesimultaneously.Therefore,fourtoeightworkpiecescanbemachinedthesametime.484814Steppingmotorsaredesignedtopositionanoutputdevice.Unlikeservomotors,theseareopenloop,meaningtheyreceivenofeedbackastowhethertheoutput devicehasrespondedasrequired.Theirinternalconstructionconsistsofanumberofmagneticstripsarrangedaroundthecircumferenceofboththerotorandthestator.Whenenergized,therotorwillmoveonestep,tothenextmagnet,foreachpulsereceived.Thustheseareintermittentmotiondevicesanddonotprovidecontinuousrotarymotionlikeothermotors.Thenumberofmagneticstripsdeterminesresolution(typicallyafewdegreesperstep).TheyarerelativelysmallcomparedtoAC/DCmotorsandhavelowtorquecapacity.Theyaremoderatelyexpensiveandrequirespecialcontrollers.子和定子組成。當(dāng)通電時(shí)，每接收一個(gè)脈沖，轉(zhuǎn)子轉(zhuǎn)動(dòng)一步（一定角度）AC/DC15Enclosingalloftheelectronicsinasinglehousinghasmanyadvantages.Forstarters,itisusuallylessexpensivetobuildandtestoneunitinsteadoftwoorthree.Consolidatingalsoeliminates,severalchips(converters, regulators, and interface ICs) that were previouslyduplicatedineachbox.Andinsteadofthreeorfourmicroprocessorsandahandfulofopamps,asmartdrivecangetbywithjustonemicrocontrollerandasingleDSPthatdigitallyclosestheposition,speed,andloops.Moreover,byclosingthefeedbackloopsinternally,smartdriversarelesspronetonoiseandotherproblemsrelatedtoexposedwires.ICs)以前重復(fù)在每個(gè)箱體內(nèi)。代替了三或四微處理器和一些運(yùn)放放大器，智DSP。此外,通過關(guān)閉內(nèi)部反饋回路,智能驅(qū)動(dòng)器更不容易受到噪聲和其他有關(guān)暴露電線問題的影響。16.Point-to-Pointsystem.Thepoint-to-pointsystemisusuallyusedinNCdrillingmachinesthatareemployedindrillingprecisionpatternsofholes.ThefunctionoftheNCsystemis,therefore,tomovethespindle(ormachinetable)totheexactlocation,asgivenbyatapecommand,sothataholecanbedrilled.Assoonasthedesiredholeisdrilled,systemmovesthespindletothenextprogrammedlocationtodrillanotherhole,andsoon.Thespindle(ormachinetable)movementfromoneholelocationtothenextmustbedoneasfastaspossibletobringtoaminimumthenonproductivetimespentinmovement.Accordingly,speedsofmorethan2500mm/minarequitecommon.（或機(jī)臺(tái)從一個(gè)孔位置到下一個(gè)的移動(dòng)必須盡可能快，以使運(yùn)動(dòng)所花費(fèi)的時(shí)間在最低限2500/分的現(xiàn)象相當(dāng)普遍。17AnothermajoradvantageofHPMisthatconventionalturningmachinescanbeusedwithworkpiecesashardas65 usingcommerciallyavailableceramicinserts.Savingoccurintwoareas,processingandcapitalinvestment.Inprocessing,themachining,setup,andtool-changingaresignificantlyreduced.Grinding-wheelchanging,ontheotherhand,istime-consuming.Guardsmustberemoved,alongwiththespindlelockingnuts,thewornwheelmustbechanged,andthenewwheelbalancedanddressed.Wheelchangingcantakeasmuchas100timeslongerthanchangingceramicinserts,whichrequireonlysimpleindexingorreplacementintheholder.HPM6510018Incontrast,nontraditionalmanufacturingprocessesharnessenergysourceconsideredunconventionalbyyesterday’sstandards.Materialremoval can now be accomplished with electrochemical reactions.High-temperatureplasmas,andhigh-velocityjetsofliquidsandabrasives.Materialthatinthebeenextremelydifficulttoform,arenowformedwithmagneticfields,explosives,andtheshockwavesfrompowerfulelectricsparks.Material-joiningcapabilitieshavebeenexpandedwiththeuseofhigh-frequencysoundwavesandbeamsofelectrons.子束的使用使材料結(jié)合的能力不斷擴(kuò)展。19AShasestablishedaqualityprogramthatinvolvesbothinternalandexternal(suppliers)standards.TheguidingphilosophybehindthisprogrambeginsbysayingthatASexiststoservetheircustomers,whichrequiresbuildingpartnershipswithcustomersandsuppliers.Thecompanymustsupportthisphilosophywithacommitmenttoinvestingintraining,re-educatingallemployees,andequipmentandtechnologyupgrading.latterincludesmodernizationofexistingplantsandbuildingnewplantswiththelatestinautomatedtechnology.Ateachdivision,keytechnicalpersonnelareworkingtobecomeandaregainingrecognitionasCertifiedQualityEngineers.AS指導(dǎo)理念是說AS的存在是為了服務(wù)于他們的客戶,這就需要與客戶和供應(yīng)商建量工程師而努力工作。20Therearethreeelementsthatprovidethebasisforareliableproduct—design,manufacturing,andc