机电专业英语第2版2Unit 2 Machine Elements机械零件-席东河-机电专业英语

MachineElementsUnit2机械零件TestingBeforeClass：Whatdoes“clutch”mean(radio)？MachineElementsCouplingsCrankshaftsandConnectingrodsMachineToolClutchBearingsMachineElements

TranslationReadingMoreTranslatingSkillsTextHoweversimple,anymachineisacombinationofindividualcomponentsgenerallyreferredtoasmachineelementsorparts.Thus,ifamachineiscompletelydismantled,acollectionofsimplepartsremainssuchasnuts,bolts,springsgears,camsandshafts—thebuildingblockofallmachinery1.Amachineelementis,therefore,asingleunitdesignedtoperformaspecificfunctionandcapableofcombiningwithotherelements.Sometimescertainelementsareassociatedinpairs2,suchasnutsandboltsorkeysandshafts.Inotherinstance,agroupofelementsiscombinedtoformasubassembly,suchasbearings,couplings,andclutches.Themostcommonexampleofamachineelementisagear,which,fundamentally,isacombinationofthewheelandthelevertoformatoothedwheel.Therotationofthisgearonahuborshaftdrivesothergearsthatmayrotatefasterorslower,dependinguponthenumberofteethonthebasicwheels.Otherfundamentalmachineelementshaveevolvedfromwheelandlever.Awheelmusthaveashaftonwhichitmayrotate.Thewheelisfastenedtotheshaftswithcouplings.Theshaftmustrestinbearings,maybeturnedbyapulleywithabeltorachainconnectingittoapulleyonasecondshaft.Thesupportingstructuremaybeassembledwithboltsorrivetsorbywelding4.Properapplicationofthesemachineelementsdependsuponknowledgeoftheforceonthestructureandthestrengthofthematerialsemployed.Theindividualreliabilityofmachineelementsbecomesthebasisforestimatingtheoveralllifeexpectancyofacompletemachine.Manymachineelementsarethoroughlystandardized.Testingandpracticalexperiencehaveestablishedthemostsuitabledimensionsforcommonstructuralandmechanicalparts.Throughstandardization,uniformityofpracticeandresultingeconomicsareobtained.Notallmachinepartsinusearestandardized,however.Intheautomotiveindustryonlyfasteners,bearings,bushings,chains,andbeltsarestandardized.Cbination[kCmbi5neiFEn]n.组合，结合individual[indi5vidjuEl]adj.单独的，各个的，个别的，特殊的component[kEm5pEunEnt]n.元件，构件，部件dismantle[dis5mAntl]vt.分解（机器），拆开，拆卸assemble[E5sembl]v.安装，装配，组合；集合，集中n组件nut[nQt]n.螺母；难对付的人；难解的问题；坚果vi.采坚果bolt[bEult]n.螺栓；（门、窗等的）插销gear[giE]n.仪器，装置；传动装置，齿轮cam[kAm]n.凸轮，偏心轮；样板，靠模，仿形板lever[5li:vE]n.杠杆，控制杆，操作杆shaft[FB:ft]n.柱身；连杆；传动轴，旋转轴；轴machinery[mE5Fi:nEri]n.机器(总称)associate[E5sEuFieit]v.联合，结合，参加，连带key[ki:]n.键，电键，开关；楔，销；钥匙subassembly[7sQbE5sembli]n.组合件，部件，机组coupling[5kQpliN]n.联轴节，联轴器；联结器，联合器clutch[klQtF]n.离合器，联轴器；夹紧装置fundamentally[fQndE5mentli]adv.（从）根本上hub[hQb]n.(轮)毂；中心；木片rotate[rEu5teit]n.(使某物)旋转或转动evolve[i5vClv]v.进化，演变；开展，发展，展开pulley[5puli]n.滑轮（组）；滑车；皮带轮rivet[5rivit]n.铆钉v铆接，铆weld[weld]v.&n.焊接，熔焊reliability[rilBiE5biliti]n.可靠性，安全性，准确性thoroughly[5WQrEli]adv.完全地，充分地，彻底地standardize[5stAndEdBiz]vt.标准化，统一标准；标定，校准establish[is5tAbliF]vt.确定，制定；建立，创办，产生；使固定dimension[di5menFEn]n.尺寸，尺度；范围，方面bushing[5buFiN]n.衬套；轴衬；轴瓦；[电]（绝缘）套管uniformity[7mju:ni5fC:miti]n.均匀性，一致性automotive[C:tE5mEutiv]adj.自动的，自动车的crank[krANk]n.曲轴refertoas称为，叫做；当做；参考作为；所说的；提到的1.Thus,ifamachineiscompletelydismantled,acollectionofsimplepartsremainssuchasnuts,bolts,springsgears,camsandshafts—thebuildingblockofallmachinery.

译文：因此，如果把机床完全拆开，就可以得到像螺母、螺栓、弹簧、齿轮、凸轮及轴等简单零件——所有机器的标准元件。2.Sometimescertainelementsareassociatedinpairs.译文：某些特定的元件必须成对地工作。说明：beassociatedwith：与……有关；涉及又如：Iassociatedwithhiminbusiness.我与他和伙经商。Theseconcernsmaybeassociatedwithstrongfeelingssuchasangerorshame.这些忧虑很可能与恼火、羞愧之类的强烈情绪有关联。3.Themostcommonexampleofamachineisagear,which,fundamentally,isacombinationofthewheelandthelevertoformatoothedwheel.译文：机器零件中最常用的是齿轮，它实际上是由轮子和杆组成的带有齿的轮子。说明：Which引导非限定性定语从句，修饰gear，不定式toformatoothedwheel作结果状语。4．Thesupportingstructuremaybeassembledwithboltsorrivetsorbywelding.译文：支撑结构可由螺栓或铆钉或通过焊接固定在一起。说明：句中withboltsorrivetsorbywelding作方式状语，beassembledwith用……安装，又如：Thebookcasecaneasilybeassembledwithascrewdriver.这书柜用一把螺丝刀就可以很容易地安装起来。

I.Answerthefollowingquestions.

Whatisreferredtoasamachineelement?Whichisthemostcommonmachineelement?2.Whatareotherfundamentalmachineelements?3.Whichmachineelementsarestandardizedintheautomotiveindustry?Amachineelementisasingleunitdesignedtoperformaspecificfunctionandcapableofcombiningwithotherelements.Themostcommonmachineelementisagear.Otherfundamentalmachineelementshaveevolvedfromwheelandlever.Intheautomotiveindustryonlyfasteners,bearings,bushings,chains,andbeltsarestandardized.keykeykeyII.Placea“T”(true)oran“F”(false)besidethesentencesaccordingtothetext.T1.Gearsareusedasbuildingblocksfortheconstructionofmostdevices,apparatus,andmachinery.2.Apairofgearswithdifferentnumbersofteethwillrotateatdifferentspeeds.3.Spurgearsandbevelgearsaredifferentintheirapplicationsbecausetheirshapesaredifferent.4.Themostcommonmachineelementisthegearfromwhichotherfundamentalmachineelementshavedeveloped.5.Acouplingisamachineelement,whichjoinstwoshafts.6.Allmachinepartshavebeendevelopedintostandardizeddesigns.FTTTFkeykeykeykeykeykeyⅢ．TranslatethefollowingsentencesintoChinese．Themostcommonmachineelementisthegear,whichcombinesthefeatureofthewheelandthelevertoformatoothedwheel.

2.Thehardnessofageardeterminesitsabilitytoresistwear.最常见的机械零件是齿轮，实际上是由轮子和杆组成的跌有齿的轮子。齿轮的坚硬性决定了它的耐磨能力。keykeyⅢ．TranslatethefollowingsentencesintoChinese．3.Manufacturingengineershavecenteredtheireffortsonthedevelopmentofstandardizedelements.4.Thesepartsareproducedinlargequantitieswithahighdegreeofperfectionatreducedcost.制造业的工程师们集中精力，研制标准化的零件。这些零件是以大批量、高规格和降低成本的条件下生产的。keykey 英汉两种语言都有一词多类、一词多义的现象。一词多类是指一个词往往属于多个词类，具有几种不同的意义。如display一词，既可做名词“显示（器）”，又可以作形容词“展览的、陈列用的”，还可做动词“显示、表现”等意思。一词多义是说同一个词类中，往往有几个不同的词义。如power一词，做名词时，其汉语意思为“电力、功率、次方”等。在英汉翻译过程中，我们在弄清句子结构后就要善于选择和确定句子中关键词的意义。选择和确定词义通常从以下几个方面入手：

词义的确定一、根据词类确定词义

选择某个词的词义时，首先要确定这个词在句中应属于哪一种词类，然后再进一步确定其词义。下面以display为例：Here,youhavetheoptionofdefiningyourowndisplayvariants.这里，你有权定义你自己的显示变式。（display为名词）Often,itisbesttodisplaymaterialsonaninformationtable.通常，最好是把资料放在提供各类资讯的桌子上展示。(display为动词)

Thereversesideofacontrolpanel,displaypanel,orthelike;thesidewiththeinterconnectingwiring.（display为形容词）控制面板、显示面板或类似的面板的反面，即带有互连接线的那一面。二、同一词类表达不同词义

英语中同一个词，同一类词，在不同的场合，往往具有不同的含义。此时，必须根据上下文的联系及整个句子的意思加以判断和翻译。例如as这一连词：Wearresistanceimprovesascuttingtoolhardnessincrease.当切削刀具的硬度越高时，其耐磨性就越好。（as引导时间状语从句）Asheatmakesthingsmove,itisaformofenergy.因为热能使物体运动，所以热是能的一种形式。（as引导原因状语从句）三、根据单词搭配情况确定词义英译汉时，不仅必须根据上下文的联系理解词义，还需要根据词的搭配情况来理解词义。尤其在科技文献中，由于学科及专业不同，同一个词在不同的专业中具有不同的意义。比如：

Thefifthpoweroftwoisthirty-two.二的五次方是三十二。（数学）

Withthedevelopmentofelectricalengineering,powercanbetransmittedoverlongdistances.随着电气工程的发展,电力能输送得非常远。（电学）

Frictioncancausealossofpowerineverymachine.摩擦能引起每一台机器功率的损耗。（物理学）四、根据名词的单复数选择词义英语中有些名词的单数或复数表达的词义完全不同。例如：名词 单数词义 复数词义facility 简易，灵巧 设施，工具charge 负荷，电荷 费用spirit 精神 酒精Althoughtheylost,theteamplayedwithtremendousspirit.那队输是输了，但却表现了极其顽强的精神。Whisky,brandy,ginandrumareallspirits.威士忌、白兰地、杜松子酒和朗姆酒都是烈酒。

CuttingTools

CuttingTools

Metalcuttingtoolsmustpossessavarietyofdifferentpropertiesinordertocutthedifferentmetalsundervaryingconditionsofseverity.Tomeetthesedemands,toolshavebeenproducedfromavarietyofmaterials.

PropertiesofCuttingToolsThemostimportantpropertiesofcuttingtoolsarehardnessathightemperature,wearresistance,andimpactstrength.切削刀具金属切削刀具必须具有许多不同的性能，才能在各种恶劣条件下切削不同的金属。为满足这些要求，制作刀具需要用许多种材料。切削刀具的性能切削刀具最重要的性能是在高温下能保持的硬度以及耐磨损耐冲击和韧性好。Asatoolcuts,highheatisdevelopedasaresultofcompressionandfrictionatthecuttingedgeofthetool.Allmetalcuttingtoolsbegintolosehardnesswhenheatedtosufficientlyhightemperatures.Asthetoolsoftensduetoheat,itwearsandbreaksdownatthecuttingedgeorface.Variouscuttingtoolmaterialsbegintolosetheirhardnessatdifferenttemperatures.Hence,thehardnessofthetoolandthedegreetowhichitremainsitshardnessathightemperatureareimportantintheselectionofacutting-toolmaterial.

当刀具进行切削时，刀具刃口处的压力和摩擦产生了高温。达到一定高的温度时，所有的金属切削刀具便开始软化。在刀口因高温而软化的同时，刀具刃口便开始磨耗并损坏。不同的切削刀具材料在不同的温度点开始软化。因此，刀具的硬度和它在高温下所能保持的硬度是选择切削刀具材料时的重要因素。Acuttingtooliswear-resistantifitresistsabrasionatthecuttingedgeandalongthetoolface.Wearresistanceimprovesascuttingtoolhardnessincreases.Cuttingtoolsmustalsohavehighstrengthinordertobevibrationandimpact-resistant.Strengthincutting-toolmaterialisnotalwaysproportionaltohardness.Someofthehardesttoolmaterialslackstrengthbecausetheyaretoobrittle.如果切削刀具的刃口和刀面耐磨，刀具就不易磨损。切削刀具的硬度越高，耐磨性就越好。切削刀具还必须具有高强度才能抗振动和抗冲击。切削刀具材料的强度并不都是与硬度成正比的。有些硬的刀具材料由于太脆而缺乏强度。MaterialsUsedinCuttingToolsThevariousmaterialsfromwhichmostmetalcuttingtoolsaremadecanbeclassifiedunderthefollowingprincipalheadings:•Carbontoolsteel•High-speedsteel•Castalloys•Cementedcarbides•Ceramics•Diamonds大多数金屑切削刀具的制作材料可分为以下几大类：碳素刀具钢；高速钢；铸合金；硬质合金；陶瓷；金刚石。Toollife,orthenumberofpartsproducedbyacutting-tooledgebeforeregrindingisrequired,isaveryimportantcostfactorinmanufacturingapartorproduct.Cuttingtoolsmustberegroundatthefirstsignofdullness.Ifatoolisusedbeyondthispoint,itwillbreakdownrapidly.

刀具寿命，即切削刀刃在需要重新打磨之前能加工的零件数，是生产某个零件或产品的重要成本因素。当切削刀具开始变钝时必须重新打磨。如果在这时还要继续用下去，刀具会很快地磨损。Inordertodetectthetimewhenacuttingtoolshouldbechanged,mostmodernmachinesareequippedwithindicatorsthatshowthehorsepowerusedduringthemachiningoperation.Whenatoolbecomesdull,morehorsepowerisrequiredfortheoperation,whichwillshowontheindicator.Whenthisoccurs,thetoolshouldberegroundimmediately.要知道什么时候该换刀具，大部分现代机床都安装了指示器来显示切削加工所耗的功率。当刀具用钝时，加工需要消耗更多的功率，并由指示器显示出来。一旦发生这种情况就应当立即打磨刀具。variety[və'raiəti]n.多样；种类；杂耍[复数varieties]property['prCpəti]n.性质，性能；财产；所有权severity[si'veriti]n.严重；严格；猛烈[复数severities]wear[wεə]n.穿著，磨损，耐久性v.穿著，用旧，耗损impact['impækt,

im'pækt]vt.影响；撞击；冲突vi.冲击n.效果；碰撞；compression[kəm'preFən]n.压缩，浓缩；压榨，压迫abrasion[ə'breiən]n.磨损；磨耗；擦伤friction['frikFən]n.摩擦，摩擦力hence[hens]adv.因此；今后proportional[prəu'pC:Fənəl]adj.比例的，成比例的；相称的n.比例项brittle['britl]adj.易碎的，脆弱的；易生气的(brittler,brittlest)carbon['kɑ:bən]n.碳；碳棒；复写纸adj.碳的；碳处理的cast[kɑ:s,kæst]vt.投，抛；计算；浇铸；投射n.投掷；铸件；铸型cement[si'ment]vt.巩固，加强；接合vi.粘牢n.水泥；接合剂carbide['kɑ:baid]n.【化学】碳化物；碳化钙regrind[ri:'ɡraind]vt.再磨研，重研磨，再磨dullness['dQlnis]n.迟钝，钝度recondition[,ri:kən'diFən]vt.修理，修复；重建；更新avarietyof种种；各种各样的impacton影响；对……冲击，碰撞1.Whatarethemostimportantpropertiesofcuttingtools?2.Whichfactorsareimportantintheselectionofacutting-toolmaterial?Why?I．Answerthefollowingquestionsaccordingtothereading．Themostimportantpropertiesofcuttingtoolsarehardnessathightemperature,wearresistance,andimpactstrength.Thehardnessofthetoolandthedegreetowhichitremainsitshardnessathightemperatureareimportantintheselectionofacutting-toolmaterial.Becauseallmetalcuttingtoolsbegintolosehardnesswhenheatedtosufficientlyhightemperatures.keykey3.Howmanysortsareclassifiedinthevariousmaterialsfromwhichmostmetalcuttingtoolsaremade?4.Whyaremostmodernmachinesequippedwithindicatorsthatshowthehorsepowerusedduringthernachiningoperation?I．Answerthefollowingquestionsaccordingtothereading．Thevariousmaterialsfromwhichmostmetalcuttin