机械工程专业英语课件-L.ppt

EnglishforMechanicalEngineering,机械工程专业英语,常州工学院机电工程学院徐红丽,机械工程专业英语,预备知识,一、预备知识,Lesson23FundamentalsofMachineTools,机床的主要部件：床身：是基础件，一般为铸件，有较高的抗压强度，吸振导轨和溜板箱：保证机床部件的直线运动，其精度极高，一般为内凹，为了储油。主轴和轴承：回转精度要求较高，径向跳动、轴向窜动和角度摆动变速机构：实现刀具相对工件的正确切削用量。机械、液压、气动、电动动力装置：电动机,词汇,二、词汇,机械工程专业英语,machinetool机床bed床身slideway导轨spindle主轴tailstock尾座dovetail燕尾槽gib镶条guard防罩roughing粗加工finishing精加工surfacefinish表面光洁度,Lesson23FundamentalsofMachineTools,机械工程专业英语,Inmanycasesproductsfromtheprimaryformingprocessesmustundergofurtherrefinementsinsizeandsurfacefinishtomeettheirdesignspecifications.Tomeetsuchprecisetolerancestheremovalofsmallamountsofmaterialisneeded.Usuallymachinetoolsareusedforsuchoperation.,课文分析,Lesson23FundamentalsofMachineTools,三、课文分析,机械工程专业英语,Inmanycasesproductsfromtheprimaryformingprocessesmustundergofurtherrefinementsinsizeandsurfacefinishtomeettheirdesignspecifications.,课文分析,许多情况下，经初步成形加工出来的工件必须在尺寸和表面光洁度方面进一步精加工整，以满足它们的设计要求。,rifainmntn.精提炼,精制;净化;精美清扫除,洗高尚,优雅精致,精细,精确,Lesson23FundamentalsofMachineTools,机械工程专业英语,Tomeetsuchprecisetolerancestheremovalofsmallamountsofmaterialisneeded.Usuallymachinetoolsareusedforsuchoperation.,课文分析,为了满足精密的公差要求，需要从工件上去掉小量材料。通常机床就是用于实现这种加工的设备。,prisaisadj.精确的,明确的;清晰的,恰好的;正当,严格的;拘泥的,陈规的,Lesson23FundamentalsofMachineTools,机械工程专业英语,IntheUnitedStatesmaterialremovalisabigbusinessinexcessof$36109peryear,includingmaterial,labor,overhead,andmachine-toolshipments,isspent.Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.,课文分析,Lesson23FundamentalsofMachineTools,机械工程专业英语,IntheUnitedStatesmaterialremovalisabigbusinessinexcessof$36109peryear,includingmaterial,labor,overhead,andmachine-toolshipments,isspent.,课文分析,在美国，材料切削业是一个很大的行业-费用每年超过36109美元，包括材料，劳动力，杂项开支，机床运输费等所花的费用。,uvhedn.经常开支,普通费用天花板;船舱的顶板,Lesson23FundamentalsofMachineTools,机械工程专业英语,Since60percentofthemechanicalandindustrialengineeringandtechnologygraduateshavesomethingconnectionwiththemachiningindustryeitherthroughsale,design,oroperationofmachineshops,orworkinginrelatedindustry,itiswiseforanengineeringstudenttodevotesometimeinhiscurriculumtostudyingmaterialremovalandmachinetools.,课文分析,由于60机械和工业技术工程专业的毕业生做销售、设计、管理机械工厂、或在相关领域工作，总要和加工工业打交道，因此，对于工程专业学生来说，在他的学习计划中安排一段时间去学习研究材料切削和机床，是非常明智的。,grdjuitn.毕业生,得学位者,Lesson23FundamentalsofMachineTools,机械工程专业英语,Amachinetoolprovidesthemeansforcuttingtoolstoshapeaworkpiecetorequireddimensions;,课文分析,Lesson23FundamentalsofMachineTools,themachinesupportsthetoolandtheworkpieceinacontrolledrelationshipthroughthefunctioningofitsbasicmembers,whichareasfollows:,机床通过使用切削刀具使工件成形以达到所要求的尺寸。,机床通过其基础构件的作用，支承相互联系的刀具和工件，现将基本部件列举如下：,机械工程专业英语,(a)Bed,Structureorframe.Thisisthemainmemberwhichprovidesabasisfor,andaconnectionbetween,thespindlesandslides;thedistortionandvibrationunderloadmustbekepttoaminimum.,课文分析,Lesson23FundamentalsofMachineTools,这是一个主要部件，该部件为主轴、拖板箱等提供一个基础支撑和中间连接，在负载作用下，它必须能使变形和振动保持最小。,机械工程专业英语,SlidesandSlideways.Thetranslationofamachineelement(e.g.theslide)isnormallyachievedbystraight-linemotionundertheconstraintofaccurateguidingsurfaces(theslideway).,课文分析,Lesson23FundamentalsofMachineTools,拖板箱和导轨。机床部件（如拖板箱）的移动，通常是在精密的导轨面约束下靠直线运动来实现。,机械工程专业英语,(c)SpindlesandBearings.Angulardisplacementstakeplaceaboutanaxisofrotation;thepositionofthisaxismustbeconstantwithinextremelyfinelimitsinmachinetools,andisensuredbytheprovisionofprecisionspindlesandbearings.,课文分析,Lesson23FundamentalsofMachineTools,主轴和轴承。角位移是绕一根旋转轴线产生的，在机床中该轴线的位置必须在极其精确的范围内保持不变，是靠高精度的主轴及其轴承来保证。,机械工程专业英语,(d)PowerUnit.Theelectricmotoristheuniversallyadoptedpowerunitformachinetools.Bysuitablypositioningindividualmotors,beltandgeartransmissionsarereducedtoaminimum.,课文分析,Lesson23FundamentalsofMachineTools,动力装置。电动机是机床中普遍采用的动力装置。通过对各个电机的合适定位，使皮带和齿轮传动装置减少到最小。,机械工程专业英语,(e)TransmissionLinkage.Linkageisthegeneraltermusedtodenotethemechanical,hydraulic,pneumaticorelectricmechanismswhichconnectangularandlineardisplacementsindefinedrelationship.,课文分析,Lesson23FundamentalsofMachineTools,变速机构。变速机构是个通用术语，用来代表机械、液压、气动或电动变速机构的，变速机构保证角位移和线性位移的确定传动比。,机械工程专业英语,Therearetwobroaddivisionsofmachiningoperations:,课文分析,Lesson23FundamentalsofMachineTools,机械加工有两个主要的组成部分：,(a)Roughing,forwhichthemetalremovalrate,andconsequentlythecuttingforce,ishigh,buttherequireddimensionalaccuracyrelativelylow.,粗加工。在粗加工中，金属切除率高，因而往往切削力也大，但所要求的尺寸精度较低。,机械工程专业英语,(b)Finishing,forwhichthemetalremovalrate,andconsequentlythecuttingforce,islow,buttherequireddimensionalaccuracyrelativelyhigh.,课文分析,Lesson23FundamentalsofMachineTools,精加工。精加工时，金属切除率低，因而相应的切削力也小，但所要求的尺寸精度和表面光洁度较高。,机械工程专业英语,Itfollowsthatstaticloadsanddynamicloads,suchasresultfromanunbalancedgrindingwheel,aremoresignificantinfinishingoperationsthaninroughingoperations.Thedegreeofprecisionachievedinanymachiningprocesswillusuallybeinfluencedbythemagnitudeofthedeflections,whichoccurasaresultoftheforceacting.,课文分析,Lesson23FundamentalsofMachineTools,机械工程专业英语,Itfollowsthatstaticloadsanddynamicloads,suchasresultfromanunbalancedgrindingwheel,aremoresignificantinfinishingoperationsthaninroughingoperations.,课文分析,Lesson23FundamentalsofMachineTools,由此可见，静载荷和由不平衡的砂轮引起的动载荷，在精加工中比粗加工中有着更为重要的影响。,机械工程专业英语,Thedegreeofprecisionachievedinanymachiningprocesswillusuallybeinfluencedbythemagnitudeofthedeflections,whichoccurasaresultoftheforceacting.,课文分析,Lesson23FundamentalsofMachineTools,任何机械加工过程所获得的精度等级通常将受到由于力的作用产生的变形量的影响。,机械工程专业英语,Machinetoolframesaregenerallymadeincastiron,althoughsomemaybesteelcastingormild-steelfabrications.Castironischosenbecauseofitscheapness,rigidity,compressivestrengthandcapacityfordampingthevibrationsset-upinmachineoperations.Toavoidmassivesectionsincastings,carefullydesignedsystemsofribbingareusedtoofferthemaximumresistancetobendingandtensionalstresses.Twobasictypesofribbingareboxanddiagonal.Theboxformationisconvenienttoproduce,aperturesinwallspermittingthepositioningandextractionofcores.Diagonalribbingprovidesgreatertensionalstiffnessandyetpermitsswarftofallbetweenthesections;itisfrequentlyusedforlathebeds.,课文分析,Lesson23FundamentalsofMachineTools,机械工程专业英语,Machinetoolframesaregenerallymadeincastiron,althoughsomemaybesteelcastingormild-steelfabrications.,课文分析,Lesson23FundamentalsofMachineTools,Castironischosenbecauseofitscheapness,rigidity,compressivestrengthandcapacityfordampingthevibrationsset-upinmachineoperations.,机床床身一般是用铸铁制造的，然而有些也可能是用铸钢或中碳钢制造的。,选用铸铁是因为它价格便宜，刚性好，抗压强度高，并且有减弱机床运行中振动的能力。,机械工程专业英语,Toavoidmassivesectionsincastings,carefullydesignedsystemsofribbingareusedtoofferthemaximumresistancetobendingandtensionalstresses.,课文分析,Lesson23FundamentalsofMachineTools,Twobasictypesofribbingareboxanddiagonal.,为了避免床身铸件截面过大，精心地设计加强筋以便提供最大的抗弯和抗扭应力的能力。,加强筋两种基本类型是：箱型结构和片状斜支撑式。,dainln.对角线,斜线,机械工程专业英语,Theboxformationisconvenienttoproduce,aperturesinwallspermittingthepositioningandextractionofcores.,课文分析,Lesson23FundamentalsofMachineTools,Diagonalribbingprovidesgreatertensionalstiffnessandyetpermitsswarftofallbetweenthesections;itisfrequentlyusedforlathebeds.,箱型结构便于生产，箱壁上有孔口便于型芯的定位和取出。,ptjun.孔,隙缝;孔径,片状斜支撑筋条有较大的抗扭刚度，亦便于排屑。它常常用于车床床身。,sw:fn.细铁屑切屑,机械工程专业英语,Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.Themovementgenerallytakestheformoftranslationinastraightline,butissometimesangularrotation,e.g.tiltingthewheel-headofauniversalthread-grindingmachinetoananglecorrespondingwiththehelixangleoftheworkpiecethread.Thebasicgeometricelementsofslidesareflat,vee,dovetailandcylinder.Theseelementsmaybeusedseparatelyorcombinedinvariouswaysaccordingtotheapplications.Featuresofslidewaysareasfollows:,课文分析,Lesson23FundamentalsofMachineTools,机械工程专业英语,Theslidesandslidewaysofamachinetoollocateandguidememberswhichmoverelativetoeachother,usuallychangingthepositionofthetoolrelativetotheworkpiece.,课文分析,Lesson23FundamentalsofMachineTools,机床的拖板箱和导轨是支撑和引导彼此相对运动的零部件，通常是改变刀具和工件的相对位置。,机械工程专业英语,Themovementgenerallytakestheformoftranslationinastraightline,butissometimesangularrotation,e.g.tiltingthewheel-headofauniversalthread-grindingmachinetoananglecorrespondingwiththehelixangleoftheworkpiecethread.,课文分析,Lesson23FundamentalsofMachineTools,相对运动一般以直线移动的方式，但有时也有相对转动，例如对应于工件的螺纹上的螺旋角方向而使万能螺纹磨床上的砂轮头转动一个角度。,机械工程专业英语,Thebasicgeometricelementsofslidesareflat,vee,dovetailandcylinder.,课文分析,Lesson23FundamentalsofMachineTools,Theseelementsmaybeusedseparatelyorcombinedinvariouswaysaccordingtotheapplications.Featuresofslidewaysareasfollows:,导轨的基本的几何结构形状有平导轨、v型导轨、燕尾导轨和圆柱形导轨。,这些导轨可根据应用场合，单独的或以各种方法组合使用。导轨的特性如下：,机械工程专业英语,(a)AccuracyofMovement.Whereaslideistobedisplacedinastraightline,thislinemustlieintwomutuallyperpendicularplanesandtheremustbenosliderotation.,课文分析,Lesson23FundamentalsofMachineTools,运动精确。由于拖板箱是要作直线移动的，这条直线必定是由两个相互垂直的平面形成而且拖板必定不存在转动。,机械工程专业英语,Thegeneraltoleranceforstraightnessofmachinetoolslidewaysis00.02mmper1000mm;onhorizontalsurfacesthistolerancemaybedisposedsothataconvexsurfaceresults,thuscounteringtheeffectof“sag”oftheslideways.,课文分析,Lesson23FundamentalsofMachineTools,机床导轨的直线度公差一般为每米00.02毫米，在垂直方向上这个公差可以进行处理成凸形表面，这样就抵消导轨下沉的作用,机械工程专业英语,(b)MeansofAdjustment.Tofacilitateassembly,maintainaccuracyandeliminate“play”betweenslidingmembersafterwearhastakenplace,astripissometimesinsertedintheslides.,课文分析,Lesson23FundamentalsofMachineTools,(b)调整方法。为了便于装配、保证精度和消除磨损后相对移动构件之间出现的“窜动”，有时在拖板内装入一个扁条。,机械工程专业英语,Thisiscalledagib-strip.Usually,thegibisretainedbysocked-headscrewspassingthroughelongatedslots;andisadjustedbygrub-screwssecuredbylocknuts.,课文分析,Lesson23FundamentalsofMachineTools,这种扁条被叫做“镶条”。通常该镶条用穿过长孔的沉头螺钉顶住，而用平头螺钉调整好后，用锁紧螺母上紧,机械工程专业英语,(c)Lubrication.Slidewaysmaybelubricatedbyeitherofthefollowingsystems:,课文分析,Lesson23FundamentalsofMachineTools,(c)润滑导轨可用以下两种装置进行润滑：,1)Intermittentlythroughgreaseoroilnipples,amethodsuitablewheremovementsareinfrequentandspeedlow.,间歇润滑，通过润滑脂嘴或油嘴进行。这是一种适于运动速度低而不频繁运动场合的润滑方法,机械工程专业英语,2)Continuously,e.g.bypumpingthroughameteringvalveandpipe-worktothepointofapplication;thefilmofoilintroducedbetweensurfacesbythesemeansmustbeextremelythintoavoidtheslide“floating”.,课文分析,Lesson23FundamentalsofMachineTools,连续润滑，例如通过油阀和油道将润滑油泵送到润滑点。用这种方法引入两表面间的油膜必定是很薄的，目的是避免使拖板“浮起”。,机械工程专业英语,Ifslidingsurfaceswereopticallyflatoilwouldbesqueezedout,resultinginthesurfacessticking.,课文分析,Lesson23FundamentalsofMachineTools,如果相对滑移表面似镜面般平滑，油就会被挤出而导致表面粘贴。,Henceinpracticeslidesurfacesareeithergroundusingtheedgeofacupwheel,orscraped.,因而在实践中，拖板滑移表面是用凹面砂轮的刃进行磨削或进行刮研的。,机械工程专业英语,Bothprocessesp