EnglishforMechanicalEngineering機械工程專業(yè)英語1課件機械工程專業(yè)英語預備知識一、預備知識Lesson23FundamentalsofMachineTools

機床的主要部件：床身：是基礎件，一般為鑄件，有較高的抗壓強度，吸振導軌和溜板箱：保證機床部件的直線運動，其精度極高，一般為內凹，為了儲油。主軸和軸承：回轉精度要求較高，徑向跳動、軸向竄動和角度擺動變速機構：實現刀具相對工件的正確切削用量。機械、液壓、氣動、電動動力裝置：電動機2課件詞匯二、詞匯機械工程專業(yè)英語machinetool機床bed床身slideway導軌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課件機械工程專業(yè)英語Inmanycasesproductsfromtheprimaryformingprocessesmustundergofurtherrefinementsinsizeandsurfacefinishtomeettheirdesignspecifications.課文分析許多情況下，經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一步精加工整，以滿足它們的設計要求。[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,精確Lesson23FundamentalsofMachineTools5課件機械工程專業(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。通常機床就是用于實現這種加工的設備。[pri’sais]adj.精確的,明確的;清晰的,恰好的;正當,嚴格的;拘泥的,陳規(guī)的Lesson23FundamentalsofMachineTools6課件機械工程專業(yè)英語IntheUnitedStatesmaterialremovalisabigbusiness—inexcessof$36×109peryear,includingmaterial,labor,overhead,andmachine-toolshipments,isspent.Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.課文分析Lesson23FundamentalsofMachineTools7課件機械工程專業(yè)英語Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.課文分析

由于60％機械和工業(yè)技術工程專業(yè)的畢業(yè)生做銷售、設計、管理機械工廠、或在相關領域工作，總要和加工工業(yè)打交道，因此，對于工程專業(yè)學生來說，在他的學習計劃中安排一段時間去學習研究材料切削和機床，是非常明智的。

[’gr?djuit]n.畢業(yè)生,得學位者Lesson23FundamentalsofMachineTools9課件機械工程專業(yè)英語Amachinetoolprovidesthemeansforcuttingtoolstoshapeaworkpiecetorequireddimensions;課文分析Lesson23FundamentalsofMachineToolsthemachinesupportsthetoolandtheworkpieceinacontrolledrelationshipthroughthefunctioningofitsbasicmembers,whichareasfollows:機床通過使用切削刀具使工件成形以達到所要求的尺寸。機床通過其基礎構件的作用，支承相互聯系的刀具和工件，現將基本部件列舉如下：10課件機械工程專業(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支撐和中間連接，在負載作用下，它必須能使變形和振動保持最小。11課件機械工程專業(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軸線產生的，在機床中該軸線的位置必須在極其精確的范圍內保持不變，是靠高精度的主軸及其軸承來保證。13課件機械工程專業(yè)英語(d)PowerUnit.Theelectricmotoristheuniversallyadoptedpowerunitformachinetools.Bysuitablypositioningindividualmotors,beltandgeartransmissionsarereducedtoaminimum.課文分析Lesson23FundamentalsofMachineTools動力裝置。電動機是機床中普遍采用的動力裝置。通過對各個電機的合適定位，使皮帶和齒輪傳動裝置減少到最小。14課件機械工程專業(yè)英語(e)TransmissionLinkage.Linkageisthegeneraltermusedtodenotethemechanical,hydraulic,pneumaticorelectricmechanismswhichconnectangularandlineardisplacementsindefinedrelationship.課文分析Lesson23FundamentalsofMachineTools變速機構。變速機構是個通用術語，用來代表機械、液壓、氣動或電動變速機構的，變速機構保證角位移和線性位移的確定傳動比。15課件機械工程專業(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課件機械工程專業(yè)英語Itfollowsthatstaticloadsanddynamicloads,suchasresultfromanunbalancedgrindingwheel,aremoresignificantinfinishingoperationsthaninroughingoperations.Thedegreeofprecisionachievedinanymachiningprocesswillusuallybeinfluencedbythemagnitudeofthedeflections,whichoccurasaresultoftheforceacting.課文分析Lesson23FundamentalsofMachineTools18課件機械工程專業(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課件機械工程專業(yè)英語Machinetoolframesaregenerallymadeincastiron,althoughsomemaybesteelcastingormild-steelfabrications.課文分析Lesson23FundamentalsofMachineToolsCastironischosenbecauseofitscheapness,rigidity,compressivestrengthandcapacityfordampingthevibrationsset-upinmachineoperations.機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，抗壓強度高，并且有減弱機床運行中振動的能力。22課件機械工程專業(yè)英語Toavoidmassivesectionsincastings,carefullydesignedsystemsofribbingareusedtoofferthemaximumresistancetobendingandtensionalstresses.課文分析Lesson23FundamentalsofMachineToolsTwobasictypesofribbingareboxanddiagonal.為了避免床身鑄件截面過大，精心地設計加強筋以便提供最大的抗彎和抗扭應力的能力。加強筋兩種基本類型是：箱型結構和片狀斜支撐式。[dai’?ɡ?nl]n.對角線,斜線

23課件機械工程專業(yè)英語Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.Themovementgenerallytakestheformoftranslationinastraightline,butissometimesangularrotation,e.g.tiltingthewheel-headofauniversalthread-grindingmachinetoananglecorrespondingwiththehelixangleoftheworkpiecethread.Thebasicgeometricelementsofslidesareflat,vee,dovetailandcylinder.Theseelementsmaybeusedseparatelyorcombinedinvariouswaysaccordingtotheapplications.Featuresofslidewaysareasfollows:課文分析Lesson23FundamentalsofMachineTools25課件機械工程專業(yè)英語Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.課文分析Lesson23FundamentalsofMachineTools機床的拖板箱和導軌是支撐和引導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動。29課件機械工程專業(yè)英語Thegeneraltoleranceforstraightnessofmachinetoolslidewaysis0~0.02mmper1000mm;onhorizontalsurfacesthistolerancemaybedisposedsothataconvexsurfaceresults,thuscounteringtheeffectof“sag”oftheslideways.課文分析Lesson23FundamentalsofMachineTools機床導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行處理成凸形表面，這樣就抵消導軌下沉的作用．30課件機械工程專業(yè)英語(b)MeansofAdjustment.Tofacilitateassembly,maintainaccuracyandeliminate“play”betweenslidingmembersafterwearhastakenplace,astripissometimesinsertedintheslides.課文分析Lesson23FundamentalsofMachineTools(b)調整方法。為了便于裝配、保證精度和消除磨損后相對移動構件之間出現的“竄動”，有時在拖板內裝入一個扁條。31課件機械工程專業(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，而用平頭螺釘調整好后，用鎖緊螺母上緊．32課件機械工程專業(yè)英語(c)Lubrication.Slidewaysmaybelubricatedbyeitherofthefollowingsystems:課文分析Lesson23FundamentalsofMachineTools(c)潤滑．導軌可用以下兩種裝置進行潤滑：1)Intermittentlythroughgreaseoroilnipples,amethodsuitablewheremovementsareinfrequentandspeedlow.間歇潤滑，通過潤滑脂嘴或油嘴進行。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行磨削或進行刮研的。35課件機械工程專業(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