機(jī)械工程專業(yè)英語-L11課件

EnglishforMechanicalEngineering機(jī)械工程專業(yè)英語1課件機(jī)械工程專業(yè)英語預(yù)備知識一、預(yù)備知識Lesson23FundamentalsofMachineTools

機(jī)床的主要部件：床身：是基礎(chǔ)件，一般為鑄件，有較高的抗壓強(qiáng)度，吸振導(dǎo)軌和溜板箱：保證機(jī)床部件的直線運動，其精度極高，一般為內(nèi)凹，為了儲油。主軸和軸承：回轉(zhuǎn)精度要求較高，徑向跳動、軸向竄動和角度擺動變速機(jī)構(gòu)：實現(xiàn)刀具相對工件的正確切削用量。機(jī)械、液壓、氣動、電動動力裝置：電動機(jī)2課件詞匯二、詞匯機(jī)械工程專業(yè)英語machinetool機(jī)床bed床身slideway導(dǎo)軌spindle主軸tailstock尾座dovetail燕尾槽gib鑲條guard防罩roughing粗加工finishing精加工surfacefinish表面光潔度Lesson23FundamentalsofMachineTools

3課件機(jī)械工程專業(yè)英語Inmanycasesproductsfromtheprimaryformingprocessesmustundergofurtherrefinementsinsizeandsurfacefinishtomeettheirdesignspecifications.課文分析許多情況下，經(jīng)初步成形加工出來的工件必須在尺寸和表面光潔度方面進(jìn)一步精加工整，以滿足它們的設(shè)計要求。[ri‘fainm?nt]n.精[提]煉,精制;凈化;精美清掃[除,洗]高尚,優(yōu)雅精致,精細(xì),精確Lesson23FundamentalsofMachineTools5課件機(jī)械工程專業(yè)英語Tomeetsuchprecisetolerancestheremovalofsmallamountsofmaterialisneeded.Usuallymachinetoolsareusedforsuchoperation.課文分析為了滿足精密的公差要求，需要從工件上去掉小量材料。通常機(jī)床就是用于實現(xiàn)這種加工的設(shè)備。[pri’sais]adj.精確的,明確的;清晰的,恰好的;正當(dāng),嚴(yán)格的;拘泥的,陳規(guī)的Lesson23FundamentalsofMachineTools6課件機(jī)械工程專業(yè)英語IntheUnitedStatesmaterialremovalisabigbusiness—inexcessof$36×109peryear,includingmaterial,labor,overhead,andmachine-toolshipments,isspent.Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.課文分析Lesson23FundamentalsofMachineTools7課件機(jī)械工程專業(yè)英語Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.課文分析

由于60％機(jī)械和工業(yè)技術(shù)工程專業(yè)的畢業(yè)生做銷售、設(shè)計、管理機(jī)械工廠、或在相關(guān)領(lǐng)域工作，總要和加工工業(yè)打交道，因此，對于工程專業(yè)學(xué)生來說，在他的學(xué)習(xí)計劃中安排一段時間去學(xué)習(xí)研究材料切削和機(jī)床，是非常明智的。

[’gr?djuit]n.畢業(yè)生,得學(xué)位者Lesson23FundamentalsofMachineTools9課件機(jī)械工程專業(yè)英語Amachinetoolprovidesthemeansforcuttingtoolstoshapeaworkpiecetorequireddimensions;課文分析Lesson23FundamentalsofMachineToolsthemachinesupportsthetoolandtheworkpieceinacontrolledrelationshipthroughthefunctioningofitsbasicmembers,whichareasfollows:機(jī)床通過使用切削刀具使工件成形以達(dá)到所要求的尺寸。機(jī)床通過其基礎(chǔ)構(gòu)件的作用，支承相互聯(lián)系的刀具和工件，現(xiàn)將基本部件列舉如下：10課件機(jī)械工程專業(yè)英語(a)Bed,Structureorframe.Thisisthemainmemberwhichprovidesabasisfor,andaconnectionbetween,thespindlesandslides;thedistortionandvibrationunderloadmustbekepttoaminimum.課文分析Lesson23FundamentalsofMachineTools這是一個主要部件，該部件為主軸、拖板箱等提供一個基礎(chǔ)支撐和中間連接，在負(fù)載作用下，它必須能使變形和振動保持最小。11課件機(jī)械工程專業(yè)英語(c)SpindlesandBearings.Angulardisplacementstakeplaceaboutanaxisofrotation;thepositionofthisaxismustbeconstantwithinextremelyfinelimitsinmachinetools,andisensuredbytheprovisionofprecisionspindlesandbearings.課文分析Lesson23FundamentalsofMachineTools主軸和軸承。角位移是繞一根旋轉(zhuǎn)軸線產(chǎn)生的，在機(jī)床中該軸線的位置必須在極其精確的范圍內(nèi)保持不變，是靠高精度的主軸及其軸承來保證。13課件機(jī)械工程專業(yè)英語(d)PowerUnit.Theelectricmotoristheuniversallyadoptedpowerunitformachinetools.Bysuitablypositioningindividualmotors,beltandgeartransmissionsarereducedtoaminimum.課文分析Lesson23FundamentalsofMachineTools動力裝置。電動機(jī)是機(jī)床中普遍采用的動力裝置。通過對各個電機(jī)的合適定位，使皮帶和齒輪傳動裝置減少到最小。14課件機(jī)械工程專業(yè)英語(e)TransmissionLinkage.Linkageisthegeneraltermusedtodenotethemechanical,hydraulic,pneumaticorelectricmechanismswhichconnectangularandlineardisplacementsindefinedrelationship.課文分析Lesson23FundamentalsofMachineTools變速機(jī)構(gòu)。變速機(jī)構(gòu)是個通用術(shù)語，用來代表機(jī)械、液壓、氣動或電動變速機(jī)構(gòu)的，變速機(jī)構(gòu)保證角位移和線性位移的確定傳動比。15課件機(jī)械工程專業(yè)英語(b)Finishing,forwhichthemetalremovalrate,andconsequentlythecuttingforce,islow,buttherequireddimensionalaccuracyrelativelyhigh.課文分析Lesson23FundamentalsofMachineTools精加工。精加工時，金屬切除率低，因而相應(yīng)的切削力也小，但所要求的尺寸精度和表面光潔度較高。17課件機(jī)械工程專業(yè)英語Itfollowsthatstaticloadsanddynamicloads,suchasresultfromanunbalancedgrindingwheel,aremoresignificantinfinishingoperationsthaninroughingoperations.Thedegreeofprecisionachievedinanymachiningprocesswillusuallybeinfluencedbythemagnitudeofthedeflections,whichoccurasaresultoftheforceacting.課文分析Lesson23FundamentalsofMachineTools18課件機(jī)械工程專業(yè)英語Itfollowsthatstaticloadsanddynamicloads,suchasresultfromanunbalancedgrindingwheel,aremoresignificantinfinishingoperationsthaninroughingoperations.課文分析Lesson23FundamentalsofMachineTools由此可見，靜載荷和由不平衡的砂輪引起的動載荷，在精加工中比粗加工中有著更為重要的影響。19課件機(jī)械工程專業(yè)英語Machinetoolframesaregenerallymadeincastiron,althoughsomemaybesteelcastingormild-steelfabrications.Castironischosenbecauseofitscheapness,rigidity,compressivestrengthandcapacityfordampingthevibrationsset-upinmachineoperations.Toavoidmassivesectionsincastings,carefullydesignedsystemsofribbingareusedtoofferthemaximumresistancetobendingandtensionalstresses.Twobasictypesofribbingareboxanddiagonal.Theboxformationisconvenienttoproduce,aperturesinwallspermittingthepositioningandextractionofcores.Diagonalribbingprovidesgreatertensionalstiffnessandyetpermitsswarftofallbetweenthesections;itisfrequentlyusedforlathebeds.課文分析Lesson23FundamentalsofMachineTools21課件機(jī)械工程專業(yè)英語Machinetoolframesaregenerallymadeincastiron,althoughsomemaybesteelcastingormild-steelfabrications.課文分析Lesson23FundamentalsofMachineToolsCastironischosenbecauseofitscheapness,rigidity,compressivestrengthandcapacityfordampingthevibrationsset-upinmachineoperations.機(jī)床床身一般是用鑄鐵制造的，然而有些也可能是用鑄鋼或中碳鋼制造的。選用鑄鐵是因為它價格便宜，剛性好，抗壓強(qiáng)度高，并且有減弱機(jī)床運行中振動的能力。22課件機(jī)械工程專業(yè)英語Toavoidmassivesectionsincastings,carefullydesignedsystemsofribbingareusedtoofferthemaximumresistancetobendingandtensionalstresses.課文分析Lesson23FundamentalsofMachineToolsTwobasictypesofribbingareboxanddiagonal.為了避免床身鑄件截面過大，精心地設(shè)計加強(qiáng)筋以便提供最大的抗彎和抗扭應(yīng)力的能力。加強(qiáng)筋兩種基本類型是：箱型結(jié)構(gòu)和片狀斜支撐式。[dai’?ɡ?nl]n.對角線,斜線

23課件機(jī)械工程專業(yè)英語Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.Themovementgenerallytakestheformoftranslationinastraightline,butissometimesangularrotation,e.g.tiltingthewheel-headofauniversalthread-grindingmachinetoananglecorrespondingwiththehelixangleoftheworkpiecethread.Thebasicgeometricelementsofslidesareflat,vee,dovetailandcylinder.Theseelementsmaybeusedseparatelyorcombinedinvariouswaysaccordingtotheapplications.Featuresofslidewaysareasfollows:課文分析Lesson23FundamentalsofMachineTools25課件機(jī)械工程專業(yè)英語Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.課文分析Lesson23FundamentalsofMachineTools機(jī)床的拖板箱和導(dǎo)軌是支撐和引導(dǎo)彼此相對運動的零部件，通常是改變刀具和工件的相對位置。26課件機(jī)械工程專業(yè)英語(a)AccuracyofMovement.Whereaslideistobedisplacedinastraightline,thislinemustlieintwomutuallyperpendicularplanesandtheremustbenosliderotation.課文分析Lesson23FundamentalsofMachineTools運動精確。由于拖板箱是要作直線移動的，這條直線必定是由兩個相互垂直的平面形成而且拖板必定不存在轉(zhuǎn)動。29課件機(jī)械工程專業(yè)英語Thegeneraltoleranceforstraightnessofmachinetoolslidewaysis0~0.02mmper1000mm;onhorizontalsurfacesthistolerancemaybedisposedsothataconvexsurfaceresults,thuscounteringtheeffectof“sag”oftheslideways.課文分析Lesson23FundamentalsofMachineTools機(jī)床導(dǎo)軌的直線度公差一般為每米0~0.02毫米，在垂直方向上這個公差可以進(jìn)行處理成凸形表面，這樣就抵消導(dǎo)軌下沉的作用．30課件機(jī)械工程專業(yè)英語(b)MeansofAdjustment.Tofacilitateassembly,maintainaccuracyandeliminate“play”betweenslidingmembersafterwearhastakenplace,astripissometimesinsertedintheslides.課文分析Lesson23FundamentalsofMachineTools(b)調(diào)整方法。為了便于裝配、保證精度和消除磨損后相對移動構(gòu)件之間出現(xiàn)的“竄動”，有時在拖板內(nèi)裝入一個扁條。31課件機(jī)械工程專業(yè)英語Thisiscalledagib-strip.Usually,thegibisretainedbysocked-headscrewspassingthroughelongatedslots;andisadjustedbygrub-screwssecuredbylocknuts.課文分析Lesson23FundamentalsofMachineTools這種扁條被叫做“鑲條”。通常該鑲條用穿過長孔的沉頭螺釘頂住，而用平頭螺釘調(diào)整好后，用鎖緊螺母上緊．32課件機(jī)械工程專業(yè)英語(c)Lubrication.Slidewaysmaybelubricatedbyeitherofthefollowingsystems:課文分析Lesson23FundamentalsofMachineTools(c)潤滑．導(dǎo)軌可用以下兩種裝置進(jìn)行潤滑：1)Intermittentlythroughgreaseoroilnipples,amethodsuitablewheremovementsareinfrequentandspeedlow.間歇潤滑，通過潤滑脂嘴或油嘴進(jìn)行。這是一種適于運動速度低而不頻繁運動場合的潤滑方法．33課件機(jī)械工程專業(yè)英語2)Continuously,e.g.bypumpingthroughameteringvalveandpipe-worktothepointofapplication;thefilmofoilintroducedbetweensurfacesbythesemeansmustbeextremelythintoavoidtheslide“floating”.課文分析Lesson23FundamentalsofMachineTools連續(xù)潤滑，例如通過油閥和油道將潤滑油泵送到潤滑點。用這種方法引入兩表面間的油膜必定是很薄的，目的是避免使拖板“浮起”。34課件機(jī)械工程專業(yè)英語Ifslidingsurfaceswereopticallyflatoilwouldbesqueezedout,resultinginthesurfacessticking.課文分析Lesson23FundamentalsofMachineTools如果相對滑移表面似鏡面般平滑，油就會被擠出而導(dǎo)致表面粘貼。Henceinpracticeslidesurfacesareeithergroundusingtheedgeofacupwheel,orscraped.因而在實踐中，拖板滑移表面是用凹面砂輪的刃進(jìn)行磨削或進(jìn)行刮研的。35課件機(jī)械工程專業(yè)英語Bothprocessesproduceminutesurfacedepressions,whichretain“pocket”ofoil,andcompleteseparationofthepartsmaynotoccuratallpoints;positivelocationoftheslidesisthusretained.課文分析Lesson23FundamentalsofMachineTools兩種工藝都可產(chǎn)生微小的表面凹痕，它就成為存油凹坑，相配合的零件就不會處處因“浮起”而發(fā)生完全分離