外文文獻(xiàn)及翻譯：發(fā)動(dòng)機(jī)零件及其工作原理和模具設(shè)計(jì)與制造

附件7密級(jí)分類(lèi)號(hào)編號(hào)成績(jī)本科生畢業(yè)設(shè)計(jì)(論文)外文翻譯原文標(biāo)題EnginePartsandOperationandMouldDesignandManufacturing譯文標(biāo)題發(fā)動(dòng)機(jī)零件及其工作原理模具設(shè)計(jì)與制造作者所在系別機(jī)械系作者所在專(zhuān)業(yè)機(jī)械設(shè)計(jì)制造及其自動(dòng)化作者所在班級(jí)作者姓名作者學(xué)號(hào)指導(dǎo)教師姓名指導(dǎo)教師職稱完成時(shí)間年月譯文標(biāo)題發(fā)動(dòng)機(jī)零件及其工作原理和模具設(shè)計(jì)與制造原文標(biāo)題EnginePartsandOperationandMouldDesignandManufacturing作者朱林楊春杰譯名國(guó)籍中國(guó)原文出處機(jī)電工程專(zhuān)業(yè)英語(yǔ)譯文：汽車(chē)要始終根據(jù)使用者的要求進(jìn)行設(shè)計(jì)。汽車(chē)上使用的發(fā)動(dòng)機(jī)必須要重量輕并且燃料損耗少，這是工程師設(shè)計(jì)各種類(lèi)型發(fā)動(dòng)機(jī)時(shí)主要考慮的兩個(gè)因素。汽車(chē)發(fā)動(dòng)機(jī)可以是單缸的，單缸發(fā)動(dòng)機(jī)只有一個(gè)氣缸，而多缸發(fā)動(dòng)機(jī)有多個(gè)氣缸，所有氣缸內(nèi)的活塞都和曲軸相連，因此發(fā)動(dòng)機(jī)可以是：?jiǎn)胃住獨(dú)飧卓赡苤绷幸部赡芩?；多缸——?dú)飧卓赡苤绷幸部赡軆A斜。如今大多數(shù)的汽車(chē)使用火花點(diǎn)火、四沖程、往復(fù)式汽油發(fā)動(dòng)機(jī)。往復(fù)式汽油發(fā)動(dòng)機(jī)每個(gè)氣缸內(nèi)都有一個(gè)圓形的活塞、一個(gè)連桿和一個(gè)曲軸。它的工作原理很簡(jiǎn)單，活塞在氣缸內(nèi)向上移動(dòng)，壓縮它上面的空氣和燃油的混合氣。壓縮使空氣和燃油非常易燃，當(dāng)活塞到達(dá)它行程的頂端時(shí)燃油混合氣被點(diǎn)燃。活塞在氣缸內(nèi)被膨脹氣體向下推，它又推動(dòng)連桿使得曲軸旋轉(zhuǎn)，曲軸回轉(zhuǎn)產(chǎn)生能量推動(dòng)汽車(chē)。伴隨曲軸轉(zhuǎn)動(dòng)，活塞又返回到氣缸頂部再一次重復(fù)循環(huán)，活塞持續(xù)上下運(yùn)動(dòng)，這就是發(fā)動(dòng)機(jī)被稱作往復(fù)式發(fā)動(dòng)機(jī)的原因。燃燒的混合氣被氣缸蓋和氣缸墊密封在氣缸的頂部，如圖26.2所示。氣缸蓋上有進(jìn)氣口和排氣口，進(jìn)氣口允許空氣燃油混合氣流入氣缸，排氣口允許燃燒后的廢氣排出，每個(gè)口都有一個(gè)氣門(mén)密封，它由凸輪軸上的凸輪翻開(kāi)，被氣門(mén)彈簧關(guān)閉，如圖26.2所示?；钊炕钊h(huán)在氣缸里密封，當(dāng)活塞上下運(yùn)動(dòng)時(shí)，活塞環(huán)沿著氣缸壁滑動(dòng)。圖26.1氣缸組成示意圖圖26.2氣缸氣門(mén)操作示意圖圖26.3四沖程循環(huán)示意圖四沖程循環(huán)在這里用單缸發(fā)動(dòng)機(jī)來(lái)描述四個(gè)沖程的循環(huán)。如圖26.3所示。汽車(chē)發(fā)動(dòng)機(jī)實(shí)際上由多個(gè)氣缸?；钊麖男谐添敹说叫谐痰锥说倪\(yùn)動(dòng)叫做一個(gè)沖程，每個(gè)循環(huán)要求燃燒空氣燃油混合氣有四個(gè)沖程，因此，叫做四沖程循環(huán)。在進(jìn)氣沖程，活塞被旋轉(zhuǎn)的曲軸向下拉，在它上方產(chǎn)生一個(gè)真空，因?yàn)樵诨钊蛳乱苿?dòng)時(shí)進(jìn)氣門(mén)翻開(kāi)，空氣燃油混合氣通過(guò)進(jìn)氣門(mén)進(jìn)入氣缸，混合氣是由燃油系統(tǒng)提供應(yīng)氣缸的。當(dāng)一局部汽油和15倍的空氣混合后尤其易燃，霧化使得混合氣體成霧狀。壓縮沖程，活塞在氣缸內(nèi)返回，壓縮混合氣體，使它更加易燃。當(dāng)活塞接近它行程的頂端時(shí)，火花塞點(diǎn)燃混合氣。做功沖程，燃燒后的混合氣體迅速膨脹，迫使活塞在氣缸內(nèi)向下移動(dòng)，當(dāng)活塞接近行程底部終點(diǎn)時(shí)，排氣門(mén)翻開(kāi)使得燃燒的氣體可以在活塞再一次在氣缸內(nèi)向上運(yùn)動(dòng)之前排出。排氣沖程，活塞向上運(yùn)動(dòng)，通過(guò)排氣門(mén)把氣缸內(nèi)殘留的廢氣擠壓出去，隨著曲軸的連續(xù)轉(zhuǎn)動(dòng)，活塞在氣缸內(nèi)上下運(yùn)動(dòng)，重復(fù)四沖程的循環(huán)。模具設(shè)計(jì)與制造CAD和CAM廣泛用于模具的設(shè)計(jì)和制造中。CAD允許你在屏幕上畫(huà)出模型，然后采用三維動(dòng)畫(huà)從各個(gè)角度進(jìn)行觀察，最后通過(guò)在數(shù)字仿真模型上引入各類(lèi)參數(shù)(壓力、溫度、沖力等)進(jìn)行測(cè)試。而CAM，從另一方面來(lái)說(shuō)，能夠控制制造質(zhì)量。這些計(jì)算機(jī)技術(shù)的優(yōu)點(diǎn)是很多的：設(shè)計(jì)時(shí)間短(可用計(jì)算機(jī)的速度進(jìn)行修改)、費(fèi)用低、制造快，等等。這種新的方法還允許進(jìn)行小批量生產(chǎn)，可以在最后一分鐘對(duì)某個(gè)特定零件的模具進(jìn)行改動(dòng)。最后這些新工藝還可用來(lái)制造復(fù)雜的零件。模具的計(jì)算機(jī)輔助設(shè)計(jì)一直以來(lái)模具的制圖是一項(xiàng)費(fèi)時(shí)的任務(wù)，它不屬于創(chuàng)造性工藝過(guò)程的一局部。制圖不是工藝過(guò)程所要求的局部，但對(duì)工藝組織不說(shuō)是必需的。計(jì)算機(jī)輔助設(shè)計(jì)(CAD)是指采用計(jì)算機(jī)及其外圍裝置來(lái)簡(jiǎn)化和提高設(shè)計(jì)過(guò)程。CAD系統(tǒng)提供了一種高效的設(shè)計(jì)方法，并且當(dāng)它和坐標(biāo)測(cè)量機(jī)器和其他檢驗(yàn)設(shè)備結(jié)合使用時(shí)可用來(lái)創(chuàng)立檢驗(yàn)程序。在選擇工藝順序時(shí)CAD數(shù)據(jù)將發(fā)揮關(guān)鍵的作用。一個(gè)CAD系統(tǒng)由3個(gè)根本的部件組成：硬件、軟件、用戶。一個(gè)典型的CAD系統(tǒng)的硬件局部包括一個(gè)處理器、一個(gè)系統(tǒng)顯示器、一個(gè)鍵盤(pán)、一個(gè)數(shù)字轉(zhuǎn)換器和一個(gè)繪圖儀。而CAD系統(tǒng)的軟件局部由允許其完成設(shè)計(jì)和畫(huà)圖功能的程序組成。用戶是模具的設(shè)計(jì)者，他采用硬件和軟件來(lái)完成設(shè)計(jì)過(guò)程。在產(chǎn)品的三維數(shù)據(jù)的根底上，應(yīng)首先對(duì)模芯和型腔進(jìn)行設(shè)計(jì)。通常設(shè)計(jì)人員先進(jìn)行零件的預(yù)設(shè)計(jì)，這意味著可以改變圍繞模芯和型腔所進(jìn)行的工作?，F(xiàn)代CAD系統(tǒng)可支持該設(shè)計(jì)，先針對(duì)確定好的畫(huà)圖方向計(jì)算出一條分模線，將零件分成模芯和型腔兩側(cè)，并生成出流外表和截流外表。在計(jì)算出零件的最正確設(shè)計(jì)草案后，再確定型腔、滑道和嵌件的位置和方向。然后在初步設(shè)計(jì)階段，粗略地定出模具部件的位置和幾何形狀——例如滑動(dòng)裝置、噴出系統(tǒng)等。有了這些信息，便可確定板的大小和厚度，并從產(chǎn)品標(biāo)準(zhǔn)目錄中選取相應(yīng)的標(biāo)準(zhǔn)模具。如果沒(méi)有一個(gè)標(biāo)準(zhǔn)的模具能滿足需要，那么選擇和要求最接近的標(biāo)準(zhǔn)模具并做相應(yīng)修改——通過(guò)調(diào)整限制和參數(shù)使得任意數(shù)量的任意尺寸的板子都能用于設(shè)計(jì)中。對(duì)功能部件進(jìn)行細(xì)化，并參加標(biāo)準(zhǔn)部件完成整個(gè)模具的設(shè)計(jì)(圖23.1)。這一切均在三維空間中進(jìn)行。此外，模具系統(tǒng)還提供了對(duì)零件進(jìn)行檢查、修改和細(xì)化的功能。早在這個(gè)階段，就可以自動(dòng)生成圖紙和材料清單了。通過(guò)運(yùn)用模具設(shè)計(jì)系統(tǒng)的三維設(shè)計(jì)及功能，可在開(kāi)始階段就消除二維設(shè)計(jì)中的典型錯(cuò)誤——例如冷卻系統(tǒng)和部件/型腔間的碰撞或孔的位置錯(cuò)誤。在任何階段都能生成材料和圖紙的清單——從而能夠準(zhǔn)時(shí)定購(gòu)材料，并且總是具備實(shí)際的文件可用來(lái)與客戶進(jìn)行探討，或者對(duì)模具制造商來(lái)說(shuō)總是能給出報(bào)價(jià)。一個(gè)特定的三維模具設(shè)計(jì)系統(tǒng)的使用能縮短研發(fā)周期。提高模具質(zhì)量，增進(jìn)團(tuán)隊(duì)合作，使設(shè)計(jì)人員從沉悶的日常工作中解脫出來(lái)。但經(jīng)濟(jì)上的成功主要取決于工作流程的組織。只有采取了適當(dāng)?shù)慕M織方法和人員評(píng)估策略才能縮短研發(fā)周期。零件設(shè)計(jì)、模具設(shè)計(jì)、電氣設(shè)計(jì)以及模具制造部門(mén)必須緊密合作，協(xié)同工作。模具的計(jì)算機(jī)輔助制造減少制造費(fèi)用和研發(fā)周期的一個(gè)方法是建立能夠充分發(fā)揮設(shè)備和人員潛能的制造系統(tǒng)。這類(lèi)制造系統(tǒng)的根底是采用CAD數(shù)據(jù)來(lái)幫助對(duì)主要工藝做出決策，使得最終能夠提高機(jī)器精度并減少不直接從事生產(chǎn)的時(shí)間。這就被稱為計(jì)算機(jī)輔助制造(CAM)。CAM的目的是，如果可能的話，通過(guò)從計(jì)算機(jī)工作站啟動(dòng)機(jī)器運(yùn)作，從而直接生產(chǎn)出模具斷面而不需要經(jīng)過(guò)中間步驟。對(duì)于一個(gè)好的CAM系統(tǒng)，自動(dòng)化不僅僅表達(dá)在某個(gè)獨(dú)立的細(xì)節(jié)上。加工工藝的自動(dòng)化還表達(dá)在組成一個(gè)零件的各個(gè)側(cè)面之間，最終導(dǎo)致方法路徑的最優(yōu)化。當(dāng)你要產(chǎn)生多種特征時(shí)，CAM系統(tǒng)會(huì)為你構(gòu)建一個(gè)工藝規(guī)劃。它會(huì)在系統(tǒng)分析的根底上指定操作步驟以減少工具的變動(dòng)以及所采用的工具的數(shù)目。在CAM方面，開(kāi)展趨勢(shì)是新技術(shù)和新工藝，例如微研磨，以支持帶復(fù)雜三維結(jié)構(gòu)和高外表質(zhì)量的高精度注塑模具的制造。CAM軟件將繼續(xù)在軟件本身固有的智能化加工的深度和廣度上開(kāi)展，直至計(jì)算機(jī)數(shù)值控制(CNC)編程工藝變成完全自動(dòng)化。對(duì)于要求加工操作步驟能更靈活地組合在一起的先進(jìn)的多功能加工工具來(lái)說(shuō)尤其如此。CAM軟件在保持機(jī)械師所需要的控制的同時(shí)，將繼續(xù)使冗余的制造工藝逐漸自動(dòng)化，使其通過(guò)計(jì)算機(jī)更快且更精確地進(jìn)行操作。在強(qiáng)調(diào)模具制造業(yè)在維持質(zhì)量的同時(shí)還要以最高效的方式制造模具的今天，模具制造商們需要緊跟最新的軟件技術(shù)包，以便使他們能夠快速地規(guī)劃并制造出復(fù)雜的模具，從而減少模具生產(chǎn)時(shí)間。簡(jiǎn)言之，模具制造業(yè)正朝著提高CAD和CAM之間以及CAM和CNC之間數(shù)據(jù)交換的質(zhì)量方向開(kāi)展，并且CAM軟件在涉及加工工藝方面變得更為智能化——從而減少了生產(chǎn)周期和總的加工時(shí)間。同時(shí)五軸加工已作為“必須有的〞加工方式出現(xiàn)在車(chē)間工場(chǎng)上——尤其是在涉及型腔較深的場(chǎng)合。隨著電子數(shù)據(jù)處理(EDP)被引入模具制造業(yè)，模具制造出現(xiàn)了新的開(kāi)展時(shí)機(jī)，從而可以縮短生產(chǎn)時(shí)間、提高本錢(qián)效率并獲得更好的質(zhì)量。原文：Automobilesaredesignedkeepinginviewtherequirementsofusers.Significantly,theenginesusedinautomobilesmustbelightinweightandtheirfuelconsumptionmustbeminimum.Thesearethetwomainconsiderationswhichhaveledengineerstodevelopvarioustypesofautomobileengines.Anenginemaybeasingle-cylinderengine.Inasingle-cylinderenginethereisonlyonecylinder,whereasinamulti-cylinderenginethereismorethanonecylinder.Thepistonsofallthecylindersareconnectedtothecommoncrankshaft.Thereforeenginesmaybe:Single-cylinderCylindermaybeverticalorhorizontalMulti-cylinderCylindermaybeverticalorinclinedtoverticalplaneMostoftoday!ˉsautomobilesusespark-ignitedfour-strokereciprocatinggasolineengines.Areciprocatinggasolineenginehasaroundpistoninacylinder,aconnectingrod,andacrankshaft.Theprincipleofitsoperationissimple.Thepistonmovesupinthecylinder,compressingamixtureofairandfuelinfrontofit.Compressingtheairandfuelmakesitveryflammable.Whenthepistonreachesthetopofitstravel,theair-fuelmixtureisignited.Asthepistonispusheddowninthecylinderbytheexpandinggases,itpushesontherod,forcingthecrankshafttorotate.Poweristakenfromtherotationofthecrankshafttopropelthecar.Asthecrankshaftturns,thepistonisreturnedtothetopofthecylindertorepeatthecycleagain.Thecontinuingup-and-downmotionofthepistoniswhytheengineiscalledareciprocatingengine.Theburningmixtureissealedintothecylinderonthetopendbyacylinderheadandaheadgasket(Fig.26.1).Thecylinderheadhasintakeandexhaustports.Theintakeportallowstheflowoftheair-fuelmixtureintothecylinder.Theexhaustportallowstheescapeoftheexhaustgasesafterthemixturehasbeenburned.Eachportissealedbyavalvethatisopenedbyalobeonthecamshaftandclosedbyaspring(Fig.26.2).Thepistonissealedtothecylinderwithpistonringsthatslideagainstthecylinderwallasthepistonmovesupanddown.Four-StrokeCycleThefour-strokecycleisdescribedhereusingasinglecylinderengine(Fig.26.3).Automobileenginesactuallyhavemultiplecylinders.Themovementofthepistonfromthetopofitstraveltothebottomofitstraveliscalledastroke.Eachcyclerequiredtoburntheair-fuelmixturehasfourstrokes.Hencethename,four-strokecycle.Fig.26.2TheValveIsOperatedbyaLobeFig.26.3TheFour-StrokeCycleDuringtheintakestroke,thepistonispulleddownbytheturningcrankshaft,creatingavacuumaboveit.Becausetheintakevalveisopenwhilethepistonismovingdown,theair-fuelmixtureisdrawnintothecylinderthroughtheintakevalveport.Themixtureissuppliedtothecylinderbythefuelsystem.Gasolineisespeciallycombustiblewhenonepartofitisatomizedwithabout15partsofair.Atomizationmakesthemixturelikefog.Thepistonmovesbackupinthecylinderonthecompressionstroke,compressingtheair-fuel,makingitfarmorecombustible.Asthepistonapproachesthetopofitstravel,asparkplugignitesthemixture.Duringthepowerstroketheburningfuelexpandsrapidly,forcingthepistontomovebackdowninthecylinder.Theexhaustvalveopensasthepistonapproachesthebottomofitstravel.Thisissothatburninggasescanescapebeforethepistonbeginstomoveupwardinthecylinderonceagain.Duringtheexhauststrokethepistonmovesbackup,forcinganyremainingexhaustgasfromthecylinderthroughtheopenexhaustvalve.Asthecrankshaftcontinuestorotate,thepistongoesbackdowninthecylinderasthefour-strokecyclerepeatsitself.MouldDesignandManufacturingCADandCAMarewidelyappliedinmoulddesignandmouldmaking.[1]CADallowsyoutodrawamodelonscreen,thenviewitfromeveryangleusing3-Danimationand,finally,totestitbyintroducingvariousparametersintothedigitalsimulationmodels(pressure,temperature,impact,etc.).CAM,ontheotherhand,allowsyoutocontrolthemanufacturingquality.Theadvantagesofthesecomputertechnologiesarelegion:shorterdesigntimes(modificationscanbemadeatthespeedofthecomputer),lowercost,fastermanufacturing,etc.Thisnewapproachalsoallowsshorterproductionruns,andtomakelast-minutechangestothemouldforaparticularpart.Finally,also,thesenewprocessescanbeusedtomakecomplexparts.Computer-AidedDesign(CAD)ofMouldTraditionally,thecreationofdrawingsofmouldtoolshasbeenatime-consumingtaskthatisnotpartofthecreativeprocess.Drawingsareanorganizationalnecessityratherthanadesiredpartoftheprocess.Computer-AidedDesign(CAD)meansusingthecomputerandperipheraldevicestosimplifyandenhancethedesignprocess.CADsystemsofferanefficientmeansofdesign,andcanbeusedtocreateinspectionprogramswhenusedinconjunctionwithcoordinatemeasuringmachinesandotherinspectionequipment.CADdataalsocanplayacriticalroleinselectingprocesssequence.ACADsystemconsistsofthreebasiccomponents:hardware,software,users.ThehardwarecomponentsofatypicalCADsystemincludeaprocessor,asystemdisplay,akeyboard,adigitizer,andaplotter.ThesoftwarecomponentofaCADsystemconsistsoftheprogramswhichallowittoperformdesignanddraftingfunctions.Theuseristhetooldesignerwhousesthehardwareandsoftwaretoperformthedesignprocess.Basedonthe3-Ddataoftheproduct,thecoreandcavityhavetobedesignedfirst.Usuallythedesignerbeginswithapreliminarypartdesign,whichmeanstheworkaroundthecoreandcavitycouldchange.ModernCADsystemscansupportthiswithcalculatingasplitlineforadefineddraftdirection,splittingthepartinthecoreandcavitysideandgeneratingtherun-offorshut-offsurfaces.Afterthecalculationoftheoptimaldraftofthepart,thepositionanddirectionofthecavity,slidesandinsertshavetobedefined.Then,intheconceptualstage,thepositionsandthegeometryofthemouldcomponents—suchasslides,ejectionsystem,etc.—areroughlydefined.Withthisinformation,thesizeandthicknessoftheplatescanbedefinedandthecorrespondingstandardmouldcanbechosenfromthestandardcatalog.Ifnostandardmouldfitstheseneeds,thestandardmouldthatcomesnearesttotherequirementsischosenandchangedaccordingly—byadjustingtheconstraintsandparameterssothatanynumberofplateswithanysizecanbeusedinthemould.Detailingthefunctionalcomponentsandaddingthestandardcomponentscompletethemould(Fig.23.1).Thisallhappensin3-D.Moreover,themouldsystemprovidesfunctionsforthechecking,modifyinganddetailingofthepart.Alreadyinthisearlystage,drawingsandbillofmaterialscanbecreatedautomatically.Fig.23.13-DSolidModelofMouldThroughtheuseof3-Dandtheintelligenceofthemoulddesignsystem,typical2-Dmistakes—suchasacollisionbetweencoolingandcomponents/cavitiesorthewrongpositionofahole—canbeeliminatedatthebeginning.Atanystageabillofmaterialsanddrawingscanbecreated—allowingthematerialtobeorderedontimeandalwayshavinganactualdocumenttodiscusswiththecustomerorabidforamouldbasemanufacturer.Theuseofaspecial3-Dmoulddesignsystemcanshortendevelopmentcycles,improvemouldquality,enhanceteamworkandfreethedesignerfromtediousroutinework.Theeconomicalsuccess,however,ishighlydependentupontheorganizationoftheworkflow.Thedevelopmentcyclescanbeshortenedonlywhenorganizationalandpersonnelmeasuresaretaken.Thepartdesign,moulddesign,electricdesignandmouldmanufacturingdepartmentshavetoconsistentlyworktogetherinatightrelationship.Computer-AidedManufacturing(CAM)ofMouldOnewaytoreducethecostofmanufacturingandreducelead-timeisbysettingupamanufacturingsystemthatusesequipmentandpersonneltotheirfullestpotential.ThefoundationforthistypeofmanufacturingsystemistheuseofCADdatatohelpinmakingkeyprocessdecisionsthatultimatelyimprovemachiningprecisionandreducenon-productivetime.Thisiscalledascomputer-aidedmanufacturing(CAM).[3]TheobjectiveofCAMistoproduce,ifpossible,sectionsofamouldwithoutintermediatestepsbyinitiatingmachiningoperationsfromthecomputerworkstation.WithagoodCAMsystem,automationdoesnotjustoccurwithinindividualfeatures.Automationofmachiningprocessesalsooccursbetweenallofthefeaturesthatmakeupapart,resultingintool-pathoptimization.Asyoucreatefeatures,theCAMsystemconstructsaprocessplanforyou.Operationsareorderedbasedonasystemanalysistoreducetoolchangesandthenumberoftoolsused.OntheCAMside,thetrendistowardnewertechnologiesandprocessessuchasmicromillingtosupportthemanufacturingofhigh-precisioninjectionmouldswithcomplex3-Dstructuresandhighsurfacequalities.CAMsoftwarewillcontinuetoaddtothedepthandbreadthofthemachiningintelligenceinherentinthesoftwareuntiltheCNCprogrammingprocessbecomescompletelyautomatic.Thisisespeciallytrueforadvancedmultifunctionmachinetoolsthatre