机械工程专业英语-翻译

Chapter55.1IntroductionConventionalmachiningisthegroupofmachiningoperationsthatusesingle-ormulti-pointtoolstoremovematerialintheformofchips.Metalcuttinginvolvesremovingmetalthroughmachiningoperations.Machiningtraditionallytakesplaceonlathes,drillpresses,andmillingmachineswiththeuseofvariouscuttingtools.Mostmachininghasverylowset-upcostcomparedwithforming,molding,andcastingprocesses.However,machiningismuchmoreexpensiveforhighvolumes.Machiningisnecessarywheretighttolerancesondimensionsandfinishesarerequired.5.1译文传统机械加工是一组利用单刃或者多刃刀具以切屑形式去除材料的加工方式。金属切削意味着通过机械加工去除金属。传统的机械加工都是利用不同的刀具在车床、钻床和铣床上进行的。与成型加工、锻压和铸造工艺相比，大多数机械加工的生产准备本钱都较低，然而如果是大批量生产，其本钱要高得多。当对零件的尺寸公差和光洁度要求较高时，机械加工是很有必要的。5.2TurningandLatheTurningisoneofthemostcommonofmetalcuttingoperations.Inturning,aworkpieceisrotatedaboutitsaxisassingle-pointcuttingtoolsarefedintoit,shearingawayexcessmaterialandcreatingthedesiredcylindricalsurface.Turningcanoccuronbothexternalandinternalsurfacestoproduceanaxially-symmetricalcontouredpart.Partsrangingfrompocketwatchcomponentstolargediametermarinepropellershaftscanbeturnedonalathe.Apartfromturning,severalotheroperationscanalsobeperformedonlathe.axially['æksiəli]adv.轴向地symmetrical[si'metrikəl]a.对称的cylindrical[si'lindrikl]a.圆柱形的contoured['kɔntuəd]a.显示轮廓的，与某种形体轮廓相吻合的译文:在金属切削加工操作中，车削是最常见的一种。在车削过程中，工件绕其轴线回转，单刃车刀沿工件进给，切除掉多余的材料，最后形成要求的圆柱形外表。车削可以加工外面和内外表以形成具有轴对称的成形工件。从怀表的零件到大直径的船用螺旋桨轴都可以在车床上加工。除了车削，还有另外几种加工操作都可以在车床上进行。Boringandinternalturning.Boringandinternalturningareperformedontheinternalsurfacesbyaboringbarorsuitableinternalcuttingtools.Iftheinitialworkpieceissolid,adrillingoperationmustbeperformedfirst.Thedrillingtoolisheldinthetailstock,andthelatteristhenfedagainsttheworkpiece.Whenboringisdoneinalathe,theworkusuallyisheldinachuckoronafaceplate.Holesmaybeboredstraight,tapered,ortoirregularcontours.Boringisessentiallyinternalturningwhilefeedingthetoolparalleltotherotationaxisoftheworkpiece.译文:利用镗杆或适宜的内圆车刀可以进行镗削和车内圆。如果工件毛坯是实心的，首先要钻孔。钻头安装在尾架上，后者向工件进给。如果在车床上进行镗削加工，工件通常装夹在卡盘或者花盘上。镗出的孔可以是直孔、锥孔或者不规那么轮廓。当将刀具沿工件的回转轴线平行进给时，镗削实际上就是车内圆。Facing.Facingistheproducingofaflatsurfaceastheresultofatool’sbeingfedacrosstheendoftherotatingworkpiece.Unlesstheworkisheldonamandrel,ifbothendsoftheworkaretobefaced,itmustbeturnedaroundafterthefirstendiscompletedandthenthefacingoperationrepeated.Thecuttingspeedshouldbedeterminedfromthelargestdiameterofthesurfacetobefaced.Facingmaybedoneeitherfromtheoutsideinwardorfromthecenteroutward.Ineithercase,thepointofthetoolmustbesetexactlyattheheightofcenterofrotation.Becausethecuttingforcetendstopushthetoolawayfromthework,itisusuallydesirabletoclampthecarriagetothelathebedduringeachfacingcuttopreventitfrommovingslightlyandthusproducingasurfacethatisnotflat.Inthefacingofcastingorothermaterialsthathaveahardsurface,thedepthofthefirstcutshouldbesufficienttopenetratethehardmaterialtoavoidexcessivetoolwear.mandrel['mændrəl]n.车床心轴clamp[klæmp]v.夹紧，夹住carriage[‘kæridʒ]n.大刀架，拖板penetrate['penitreit]v.穿透，渗透toolwear刀具磨损译文:车端面可以加工出一个平面，它是当车刀沿回转工件的端面横向进给的结果。除非工件固定在心轴上，如果工件两端都要车端面，必须将一端加工完成后，将工件调头，重复进行车端面加工。车削速度必须由所加工外表的最大直径来决定。车端面可以由外向内也可以由中心向外进行。无论哪种情况，刀尖必须准确地与回转中心对正。由于切削力有将车刀推离工件的趋势，通常最可行的就是在车端面时将拖板卡紧在床身上以防止车刀轻微移动造成加工外表不平整。在对具有硬质外表的铸件或其他材料进行车端面加工时，首次切深要足以穿透硬质材料从而防止过度的刀具磨损。Parting.Partingistheoperationbywhichonesectionofaworkpieceisseveredfromtheremainderbymeansofcutofftool.Becausecuttingtoolsarequitethinandmusthaveconsiderableoverhang,thisprocessislessaccurateandmoredifficult.Thetoolshouldbesetexactlyattheheightofaxisofrotation,bekeptsharp,haveproperclearanceangles,andbefedintotheworkpieceataproperanduniformfeedrate.remainder[ri'meində]剩余物，余数overhang['əuvə'hæŋ]vt.悬于...之上n.伸出;突出uniform['ju:nifɔ:m]a.相同的,一致的n.制服;军服clearanceangles后角译文:切断是一种利用切断刀〔割刀〕将工件的一局部与其剩余局部脱离的加工方法。由于切断刀非常薄而且处于悬臂状态，因此这种加工方法不太精确而且加工起来常常比拟困难。切断刀必须准确地对正回转轴，保持锋利，具有适宜的后角，以适宜、不变的进给率沿工件进给。Threading.Threadingcanbeconsideredasturningsincethepathtobetravelledbythecuttingtoolishelical.However,therearesomemajordifferencesbetweenturningandthreading.Whileinturning,theinterestisingeneratingasmoothcylindricalsurface,inthreadingtheinterestisincuttingahelicalthreadofagivenformanddepthwhichcanbecalculatedfromtheformulae.译文:车螺纹可以看作是车削，只是车刀所形成的加工轨迹是螺旋线。但二者也存在一些不同之处。车削主要考虑能否生成光滑的圆柱形外表，而车螺纹注重的是能否切出具有按公式计算出来的规定形状和深度的螺旋线。Therearetwobasicrequirementsforthreadcutting.• Anaccuratelyshapedandproperlymountedtoolisneededbecausethreadcuttingisaform-cuttingoperation.Theresultingthreadprofileisdeterminedbytheshapeofthetoolanditspositionrelativetotheworkpiece.• Thesecondbyrequirementisthatthetoolmustmovelongitudinallyinaspecificrelationshiptotherotationofworkpiece,becausethisdeterminestheleadofthethread.Thisrequirementismetthroughtheuseoftheleadscrewandthesplitunit,whichprovidepositivemotionofcarriagerelativetotherotationofspindleform-cuttingoperation成形加工longitudinally[lɔ:ŋdʒi'tju:dinəli]adv.纵向leadscrew丝杠splitunit开合机构译文:车螺纹有两个根本要求：首先，由于车螺纹是一种成形加工，因此车刀必须具有准确的形状而且要安装适宜。所切出的螺纹外形是由车刀形状和它与工件的相对位置决定的。其次，车刀的纵向进给与工件的回转运动具有特定的关系，因此这决定了螺纹的导程。这个条件可以通过采用丝杠和开合机构得到满足，它们可以实现拖板相对于主轴回转运动的精确可靠的运动1.Enginelathes普通车床2.Verticallathes立式车床3.Turretlathes转塔车床5.Contouringlathes仿形车床6.Universallathes万能车床Lathebedisfoundationoftheenginelathe,whichheavy,ruggedcastingismadetosupporttheworkingpartsofthelathe.Thesizeandmassofthebedgivestherigiditynecessaryforaccurateengineeringtolerancesrequiredinmanufacturing.Ontopofthebedaremachinedslidewaysthatguideandalignthecarriageandtailstock,astheyaremovefromoneendofthelathetotheother.ruggedadj.健壮，巩固massn.质量slidewaysn.导轨床身是普通车床的根底，它是由沉重而巩固的铸件制作而成的，其目的是为了支撑车床的工作部件。床身的尺寸和质量要使车床具有足够的刚性以保证制造过程中获得所需的工程公差。床身上的导轨可以引导和对准拖板和尾座，使它们可以从车床的一端移动到另一端。• Headstockisclampedatopthebedatleft-handendofthelatheandcontainsthemotorthatdrivesthespindlewhoseaxisisparalleltotheguidewaysthroughaseriesofgearshousedwithinthegearbox.Thefunctionofgearboxistogenerateanumberofdifferentspindlespeeds.• atopadv.在(…)顶上• gearbox齿轮箱床头箱〔主轴箱〕紧固在床身上面的左端，内装有电机，它通过变速箱内的一组齿轮来驱动主轴转动，主轴的轴线平行于导轨。变速箱的功能是可以产生不同的主轴转速。• Aspindlegearismountedontherearofthespindletotransmitpowerthroughthechangegearstothefeedingboxthatdistributesthepowertotheleadscrewforthreadingortothefeedrodforturning.• ontherearof在…的尾部• changegears挂轮• leadscrew丝杠• feedrod光杠主轴齿轮安装在主轴的尾部，通过挂轮把动力传递到进给箱，如果是车螺纹，进给箱将动力分配到丝杠上；如果是车削，就将动力分配到光杠上。• Thespindlehasathroughholeextendinglengthwisethroughwhichbarstockscanbefedifcontinuousproductionisused.Theholecanholdaplainlathecenterbyitstaperedinnersurfaceandmountachuck,afaceplateorcolletbyitsthreadedoutersurface.• tapern.坡度，锥形v.锥度加工• colletn.夹头主轴有一个纵向通孔，如果连续加工棒料，通孔就用来实现棒料的送料。这个通孔具有一个内锥面，可以安装普通车床的中心顶尖。主轴的外外表车有螺纹，可以安装卡盘，花盘或夹头。CarriageassemblyisactuallyanH-shapedblockthatsitsacrosstheguidewaysandinfrontoflathebed.Thefunctionofthecarriageistocarryandmovethecuttingtoollongitudinally.Itcanbemovedbyhandorbypowerandcanbeclampedintopositionwithalockingnut.Thecarriageiscomposedofthecrossslide,compoundrest,toolsaddle,andapron.拖板组件实际上是一个H形的铸件，位于床身的前端并横跨在导轨上。拖板的功能带动刀具纵向移动，这个可以通过手动或者自动完成。利用锁紧螺母可以将其卡紧在所需位置。拖板组件由横拖板，小刀架，刀架鞍板和溜板箱组成。• Thecrossslideismountedonthedovetailguidewaysonthetopofthesaddleanditmovedbackandforthat90°totheaxisofthelathebythecrossslideleadscrew.Theleadscrewcanbehandorpoweractivated.• dovetail燕尾槽横拖板安装在刀架鞍板上部的燕尾槽导轨上。它利用横拖板丝杠于车床轴线成90度夹角的方向上前后移动。丝杠可以手动或者自动驱动。• Thecompoundrestismountedonthecrossslideandcanbeswiveledandclampedatanyangleinahorizontalplane.Thecompoundistypicallyusedforcuttingchamfersortapers,butmustalsobeusedwhencuttingthread.Thecompoundrestcanonlybefedbyhand.Thereisnopowertocompoundrest.Thecuttingtoolandtoolholderaresecuredinthetoolpostwhichismounteddirectlytothecompoundrest.• swivel['swɪvəl]v.旋转小刀架安装在横拖板上，它可以在水平面内转动或夹紧在任意角度位置。小刀架主要用来倒角和加工锥面，在车削螺纹时也必须用到小刀架。小刀架只能手动进给，没有动力传到小刀架上。刀具和刀夹被卡紧在直接安装在小刀架上的刀座上。ThetoolsaddleisanHshapedcastingmountedonthetopoftheguidewaysandhousesthecrossslideandcompoundrest.Itmakespossiblelongitudinal,crossandangularfeedingofthetoolbit.• 刀架鞍板是一个安装在导轨上部的H形铸件，容纳有横拖板和小刀架。它可以实现刀尖的纵向、横向和斜向进给。Theapronisattachedtothefrontofthecarriageandcontainsthegearsandfeedclutcheswhichtransmitmotionfromthefeedrodorleadscrewtocarriageandcrossslide.Whencuttingscrewthreads,powerisprovidedtothegearboxoftheapronbytheleadscrew.Inallotherturningoperations,itisthefeedrodthatdrivesthecarriage.• 溜板箱位于拖板的前端，里面装有齿轮和将运动从光杠或丝杠传递至拖板或横向拖板的进给离合器。当切制螺纹时，动力通过丝杠传递到溜板箱中的变速齿轮箱。在其它车削加工时，依靠光杠来驱动拖板。• Tailstockiscomposedofalowbaseandthemovablepartofthetail-stockproper,thetransverseadjustmentsbeingmadewithacrossscrewfurnishedwithasquarehead.Thetwopartsareholdtogetherbytheholding-downboltswhichsecurethetailstocktothebed.• transverseadj.横向的，横切的；n.横轴• holding-downbolts压紧螺栓尾座由底座和尾座体的可移动部件组成。课移动部件的横向调整有带有四方头的横向丝杠来完成。底座和可移动局部通过压紧螺栓连接在一起并将尾座固定在床身上。Chapter66.1Traditionalorconventionalmachining,suchasturning,milling,andgrindingetc.，usesmechanicalenergytoshearmetalagainstanothersubstancetocreateholesorremovematerial.Non-traditionmachiningprocessesaredefinedasagroupofprocessesthatremoveexcess传统或传统的加工,如车削、铣削、磨削等,使用机械能剪切金属反对另一种物质来创立洞或删除材料。非传统加工过程被定义为一组进程,去除多余materialbyvarioustechniquesinvolvingmechanical,thermal,electricalorchemicalenergyorcombinationsoftheseenergiesbutdonotuseasharpcuttingtoolasitisusedintraditionalmanufacturingprocesses.[1]材料的各种技术涉及机械、热、电力或化学能源或组合这些能量但不使用锋利的刀具,因为它是用在传统的制造过程。[1]Extremelyhardandbrittlematerialsarcdifficulttobemachinedbytraditionalmachiningprocesses.Usingtraditionalmethodstomachinesuchmaterialsmeansincreaseddemandfortimeandenergyandthereforeincreasesincosts;insomecasestraditionalmachiningmaynotbefeasible.Traditionalmachiningalsoresultsintoolwearandlossofqualityintheproductowingtoinducedresidualstressesduringmachining.极高的硬度、脆性材料电弧很难通过传统加工过程的加工。使用传统方法来机这样的材料意味着需求增加的时间和精力,因此增加的本钱;在某些情况下传统加工可能不可行。传统的加工刀具的磨损,也会导致失去质量的产品由于诱导剩余应力在加工过程中。Non-traditionalmachiningprocesses,alsocalledunconventionalmachiningprocessoradvancedmanufacturingprocesses,areemployedwheretraditionalmachiningprocessesarenotfeasible,satisfactoryoreconomicalduetospecialreasonsasoutlinedbelow:非传统加工过程,也称为非常规加工过程或先进的生产工艺,采用传统加工过程不可行,满意或经济因特殊原因如下所示:1.Verybardfragilematerialsdifficulttoclampfortraditionalmachining;1。非常脆弱的材料很难夹巴德传统加工;2.Whentheworkpieceistooflexibleorslender,2。当工件太灵活或苗条,3.Whentheshapeofthepartistoocomplex;3。当形状的局部是过于复杂;4.Partswithoutproducingbunsorinducingresidualstresses.4。局部没有生产面包或诱导剩余应力。Traditionalmachiningcanbedefinedasaprocessusingmechanical(motion)energy.传统加工可以被定义为一个流程使用机械(运动)能量。Non-traditionalmachiningutilizesotherformsofenergy;thethreemainformsofenergy非传统加工利用其他形式的能源;三种主要形式的能量usedinnon-traditionalmachiningprocessesareasfollows:用于非传统加工过程如下:1.Thermalenergy;1。热能;2.Chemicalenergy-,2。化学能源-,3.Electricalenergy.3。电能。Severaltypesofnon-traditionalmachiningprocesseshavebeendevelopedtomeetextrarequiredmachiningconditions.Whentheseprocessesareemployedproperly,theyoffermanyadvantagesovertraditionalmachiningprocesses.Thecommonnon-traditionalmachiningprocessesaredescribedinthefollowingsection.几种类型的非传统加工过程已经被开发出来,以满足额外的要求加工条件。当这些流程是正确使用,他们提供了许多优点比传统的加工过程。常见的非传统加工过程是下一节描述。6.2ElectricalDischargeMachining(EDM)6.2电火花加工(EDM)Electricaldischargemachining(EDM)sometimesiscolloquiallyreferredtoassparkmachining,sparkeroding,burning,diesinkingorwireerosion.Itisoneofthemostwidelyusednon-traditionalmachiningprocesses.ThemainattractionofEDMovertraditionalmachiningprocessessuchasmetalcuttingusingdifferenttoolsandgrindingisthatthistechniqueutilizesthermoelectricprocesstoerodeundesiredmaterialsfromtheworkpiecebyaseriesofrapidlyrecurringdiscrete-electricalsparksbetweenworkpieceandelectrode.[2]电火花加工(EDM)有时是通俗地称为电火花加工、电火花侵蚀,燃烧,开模或钢丝侵蚀。这是一个最广泛使用的非传统加工过程。主要的吸引力比传统的电火花加工过程,如金属切削使用不同的工具和磨削是这种技术利用热电过程侵蚀无用的材料工件的一系列迅速反复出现的离散-电火花工件和电极之间。[2]Thetraditionalmachiningprocessesrelyonhardertoolorabrasivematerialtoremovethesoftermaterialwhereasnon-traditionalmachiningprocessessuchasEDMuseselectricalsparkorthermalenergytoerodeunwantedmaterialinordertocreatedesiredshapes.So,thehardnessofthematerialisnolongeradominatingfactorforEDMprocess.传统的加工流程依赖困难工具或研磨材料去除软材料而非传统加工如EDM使用电火花或热能侵蚀多余的材料以创立所需的形状。所以,硬度的材料不再是一个主要因素电火花放电加工。EDMremovesmaterialbydischarginganelectricalcurrent,normallystoredinacapacitorbank,acrossasmallgapbetweenthetool(cathode)andtheworkpiece(anode)typicallyintheorderof50volts/l0amps.AsshowninFig-6.1,atthebeginningofEDMoperation,ahighvoltageisappliedacrossthenarrowgapbetweentheelectrodeandtheworkpiece.Thishighvoltageinducesanelectricfieldintheinsulatingdielectricthatispresentinnarrowgapbetweenelectrodeandworkpiece.Thiscauseconductingparticlessuspendedinthedielectrictoconcentrateatthepointsofstrongestelectricalfield.Whenthepotentialdifferencebetweentheelectrodeandtheworkpieceissufficientlyhigh,thedielectricbreaksdownandatransientsparkdischargesthroughthedielectricfluid,removingsmallamountofmaterialfromtheworkpiecesurface.Thevolumeofthematerialremovedpersparkdischargeistypicallyintherangeof10-5to10-6mm3.Thegapisonlyafewthousandthsofaninch,whichismaintainedataconstantvaluebytheservomechanismthatactuatesandcontrolsthetoolfeed.除材料的电火花加工放电电流,通常存储在电容器银行,在一个小差距工具(阴极)和工件(阳极)通常在订单50伏特/10安培。图6所示。1,开始时,一个高压电火花加工操作是应用在狭窄的电极之间的差距和工件。这个高电压产生电场在绝缘介质中存在的差距和工件之间的狭窄电极。这导致导电粒子悬浮在介质集中点的最强的电场。当潜在的区别和工件的电极是足够高,电介质分解和瞬时放电通过电介质,消除少量的材料从工件外表。材料去除的体积每火花放电通常在10-5到10-6的范围mm3。这个差距只有几英寸的秒这个级别,这是维持在一个恒定值由伺服机构,促动和控制工具进给。Chapter77.1Introduction7.1引入Qualityandaccuracyaremajorconsiderationsinmakingmachinepartsorstructures.质量和准确性是主要的考虑因素在制造机零件或结构。Interchangeablepartsrequireahighdegreeofaccuracytofittogether.Withincreasingaccuracyorlessvariationinthedimension,thelaborandmachineryrequiredtomanufactureapartismorecostintensive.[l]Anymanufacturershouldhaveathoroughknowledgeofthetolerancestoincreasethequalityandreliabilityof'amanufacturedpartwiththeleastexpense.具有互换性的零件需要一个高精确度来组装在一起。随着准确性或更少的变异在尺寸、劳动和机械需要制造一个局部是更多的本钱密集型。[]是任何制造商应该有一个全面的知识的公差,以便提高质量和可靠性的一个制造最少的局部费用。Anengineeringdrawingmustbeproperlydimensionedinordertoconveythedesigner'sintenttotheenduser.Dimensionsofpartsgivenonblueprintsandmanufacturedtothosedimensionsshouldbeexactlyalikeandfitproperly.Unfortunately,itisimpossibletomakethingstoanexactordimension.Mostdimensionshaveavaryingdegreeofaccuracyandameansofspecifyingacceptablelimitationsindimensionalvariancesothatamanufacturedpartwillbeacceptedandstillfunction.Itisnecessarythatthedimensions,shapesandmutualpositionofsurfacesofindividualpartsarekeptwithinacertainaccuracytoachievetheircorrectandreliablefunctioning.Routineproductionprocessesdonotallowmaintenance(ormeasurement)ofthegivengeometricalpropertieswithabsoluteaccuracy.[2]Actualsurfacesoftheproducedpartsthereforedifferfromidealsurfacesprescribedindrawings.Deviationsofactualsurfacesaredividedintofourgroupstoenableassessment,prescriptionandcheckingofthepermittedinaccuracyduringproduction:一个工程图纸必须得到适当的尺寸,以传达设计者的意图给最终用户。维度上给出的局部设计图和制造这些维度应该完全一样,恰到好处。不幸的是,它是不可能让事情一个确切的或维度。大多数维度有不同程度的准确性和一种方式来指定可接受的限制在维方差这样一个人造的局部会被接受,还是函数。这是必要的,尺寸、形状和外表的相互位置的各个局部都保持在一定的精度,到达他们的正确和可靠的功能。日常生产过程不允许维护(或测量)给定的几何属性以绝对的精度。[2]实际外表产生局部因此不同于理想的外表在图纸规定。偏离实际的外表分为四组,使评估、处方和检查错误的允许生产过程中:1.Dimensionaldeviations;1。尺寸偏差;2.Shapedeviations;2。形状的偏差;3.Positiondeviations;3。位置偏差;4.Surfaceroughnessdeviations.4。外表粗糙度的偏差。Asmentionedabove,itisprincipallyimpossibletoproducemachinepartswithabsolutedimensionalaccuracy.Infact,itisnotnecessaryoruseful.Itisquitesufficientthattheactualdimensionofthepartisfoundbetweentwolimitdimensionsandapermissibledeviationiskeptwithproductiontoensurecorrectfunctioningofengineeringproducts.Therequiredlevelofaccuracyofthegivenpartisthengivenbythedimensionaltolerancewhichisprescribedinthedrawing.Theproductionaccuracyisprescribedwithregardstothefunctionalityoftheproductandtotheeconomyofproductionaswell.Theprincipalfactorusedtosetatoleranceforadimensionshouldbethefunctionofthefeaturebeingcontrolledbythedimension.Unnecessarilytighttolerancesleadtohighcostofmanufactureresultingfrommoreexpensivemanufacturingmethodsandhigherrejectrates.正如上面提到的,主要是不可能产生机器零件与绝对尺寸精度。事实上,这是没有必要的或有用的。这是很充足的,实际的维度的局部是发现在两个限制维度和一个容许偏差保持与生产,确保正确运转的工程产品。所需的精确度上给定的局部是然后给出的尺寸公差,按照图纸。生产精度是规定的关于产品的功能和经济的生产。校长因子用于设置一个容忍一个维度应该函数的特性被控制的维度。不必要地紧公差导致高本钱的生产造成更昂贵的制造方法和更高的拒绝利率。7.2Tolerances7.2公差Toleranceisthetotalamountthataspecificdimensionispermittedtovary.Itisthedifferencebetweenthemaximumandtheminimumlimitsforthedimension.Tounderstandtolerances,youshouldunderstandsomeofthedefinitionsassociatedwiththedeterminationofatolerance.Thesedefinitionsmaybegenerallycategorizedasrelatingtosize,allowance,orfit.宽容是一个特定的总量维度是允许不同。它的区别是最大值和最小值限制为该维度。理解公差,你应该了解一些相关的定义确实定公差。这些定义可能是一般分为大小有关,津贴,或配合。Size.Thesizeofanobjectoritsmateis(mownasnominal,basic,ordesignsize.大小。一个物体的大小或其配偶是(割、根本或随着名义设计尺寸。Allowance.Thedifferencebetweenthelargestallowableshaftsizeandthesmallestholediameteristermedastheallowance.[3]Thequalityofthefitischaracterizedbytheallowancevalue.津贴。最大的区别允许轴尺寸和最小的孔直径是被称为津贴。[3]适宜的质量特征是津贴值。Fit.clearance,interference,ortransitionfitrefertohowtheobjectfitsanassembly.配合。间隙,干扰,或过渡配合引用的对象如何适合一个装配。Tospecifythesizeofanobject,wedimensionitwithanominalsize,basicsize,andactualsizeshowninFig.7.1.指定一个物体的大小,我们尺寸用公称尺寸、根本大小和实际大小显示在图71。Nominalsize(basicsize).Itisthedesignationusedforgeneralidentificationandusuallyexpressedincommonfractions.Itisanexacttheoreticalsizeofapartfromwhichlimitdimensionsarecomputed.Thenominalsizeofapartshouldbeselectedfromthepreferreddimensionseriesindicatedbythenationalstandard.(4J(showninFig.7.Ia)公称尺寸(根本的大小)。它是指定用于通用识别和通常表示在常见的分数。这是一个精确的理论大小的局部限制尺寸计算。名义尺寸应该选择一局部来自首选尺寸系列表示由国家标准。(4j(见图7ia)imitsize.ItincludesupperlimitsizeandlowerlimitsizewhichareallowableextremesizesofapartFoxexample,thelimitsforaholearc1500(lowerlimit)and1.501(upperlimit)andforashaftI.499(upperlimit)and1.497(lowerlimit),showninFig.7.Ib.Actualsize.Itisthemeasuredsizeofthefinishedpart,showninFig.7.Ic.l模仿的大小。它包括上限和下限尺寸大小是容许极端大小的一个局部例如,限制一个孔弧1500(下限)和1.501(上限)和一个轴我。499(上限)和1.497(下限),图7所示。我b。实际大小。这是测量的大小已完成局部,见图7iclDeviations,allowancerefertosizeallowablevariations.偏差,津贴指大小容许变化。Deviations.Theupperandlowerdeviationsobtainedbysubtractingbasicsizefromlimitsize.Forexample,aholedimensionedas,thusupperdeviationis+0.0004andlowerdeviationis-0.0004.偏差。上部和下部偏差得到根本尺寸大小中减去从限制。例如,一个孔尺寸作为,因此上偏差是+0.0004和更低的偏差为-0.0004。Allowance.Theintentionaldifferencebetweenthemaximummateriallimitsofmatingparts.Thisisaminimumclearance(positiveallowance)ormaximuminterference(negativeallowance)betweenmatingparts.津贴。成心差异最大材料限制的配件。这是一个最小间隙(积极的津贴)或最大干扰(负公差)之间的配件。Tolerancescanbeexpressedineitheroftwoways.公差可表示成两种方式中的任何一个。BilateralTolerances.Abilateraltoleranceisatoleranceinwhichvariationispermittedinbothdirectionsfromaspecifieddimension.Examp1eis2.00010.0004.Forthisexpression,thedimensionofthepartwouldbepermittedtovarybetween1.996and2.004foratotaltoleranceof0.008.双边公差。一个双边公差是一个宽容的变化是不被允许在两个方向上从一个指定的尺寸。Examp1e是2.00010.0004。对于这个表达式,该维度的局部将被允许在1.996和2.004之间不同共0.008的容忍。Theactualsizeoftheobjectmaybelargerorsmallerthanthestatedsizelimitationif实际大小的对象可能大于或小于规定的大小限制如果therecanbeequalvariationinbothdirections.Theplusandminuslimitationscombineto可以有相等的两个方向的变化。正负局限结合起来formasinglevalue.[5J形成一个单一值。[5jUnilateralTolerances.Aunilateraltoleranceisatoleranceinwhichvariationispermittedonlyinonedirectionfromthespecifieddimension.Exampleis2.OOO;"Forthisexpression.thedimensionofthepartwouldbepermittedtovarybetween2.000and2.008foratotaltoleranceof0.008.单方面的公差。一个单边公差是一个宽容的变化只能在一个方向从指定的尺寸。例子是2。OOO;“这个表达式。局部的尺寸会允许变化在2.000和2.008之间总公差为0.008。Unilateraltoleranceexpressionhastheadvantagethattheyareeasiertocheckondrawingsandthatthechangeinthetolerancecanbemadewiththeleastdisturbancetootherdimensions.单边公差表达式的优势在于,他们更容易检查图纸,宽容的变化可以用最少的干扰到其他维度。7.3Fits7.3适合Howmatingpartsorassembliesfittogetherwithcomponentpartsisreferredtoasfit,如何交配局部或组件组合在一起以组成局部被称为健康,whichincludesclearancefit,interferencefit,ortransitionfit,seeFig.7.3.其中包括间隙配合,干预配合,或过渡配合,见图7.3。Fitisthegeneralrangeoftightnessresultingfromtheapplicationofaspecificcombinationofallowanceandtolerancesinthedesignofmatingparts.配合是一般的一系列紧张造成的特定组合的应用的津贴和公差设计的配件。Clearancefit.Itisafitenablingaclearancebetweentheholeandshaftinthecoupling.Thelowerlimitsizeoftheholeisgreateroratleastequaltotheupperlimitsizeoftheshaft.间隙配合。这是一个适合启用一个间隙孔和轴的耦合。下限大小的洞是更大的或至少等于上限大小的轴。Interferencefit.Itisafitalwaysensuringsomeinterferencebetweentheholeandshaftinthecoupling.Theupperlimitsizeoftheboleissmalleroratleastequaltothelowerlimitsizeoftheshaft.干预配合。这是一个适合总是确保一些干扰洞和轴之间的耦合。大小上限的树干是较小的或者至少等于下限大小的轴。Transitionfit.Itisafitwhere(dependingontheactualsizesoftheholeandshaft)bothclearanceandinterferencemayoccurinthecoupling.Tolerancezonesoftheholeandshaftpartlyorcompletelyinterfere.过渡配合。这是一个符合(取决于实际大小的孔、轴)两个间隙和干扰可能发生耦合。公差带的孔、轴局部或完全干预。Chapter88.1Introduction8.1引入Toensurethattheworkpieceisproducedaccordingtothespecifiedshape,dimensionsandtolerances,itisessentialthatworkplaceshouldbeappropriatelylocatedandclampedonthemachinetool.[11Productiondevicesaregenerallyworkholderswith/withouttoolguiding/settingarrangementThesearecalledjigsandfixtures.Afixtureisaproductiontoolthatlocates,holdsandsupportstheworkpiecesecurelysothateachpartismachinedwithinthespecifiedlimits.Itmustcorrectlylocateawork-pieceinagivenorientationwithrespecttoacuttingtoolormeasuringdevice,orwithrespecttoanothercomponent,asforinstanceinassembly.Suchlocationmustbeinvariantinthesensethatthedevicesmustclampandsecuretheworkpieceinthatlocationfortheparticularprocessingoperation.Fixturesaregenerallyusedinmachining(milling,planning,shapingandturning,etc.)andothermanufacturingoperations,suchaswelding,heattreatment,machininginspectionandassemblyetc.Jigsareprovidedwithtoolguidingelementssuchasdrillbushes.Theydirectthetooltothecerectpositionontheworkpiece.Jigsarerarelyclampedonthemachinetablebecauseitisnecessarytomovethejigonthetabletoalignthevariousbushinginthejigwiththemachinespindle.确保工件生产根据指定的形状、尺寸和公差,至关重要的是,工作场所应该适当地找到并固定在机床。[11生产设备通常workholders与/没有工具指导/设置安排这些被称为工装夹具。一个fixtureis生产工具,定位、持有和支持工件平安地,以便每个局部是加工在指定的限制。它必须正确定位一个工件在给定的取向对刀具或测量设备,或对另一个组件,比方在大会。这样的位置必须是不变的,在这个意义上,这个设备必须夹和平安中,工件的位置,为特定处理操作。装置通常用于加工(铣床、规划、塑造和转动,等等)和其他制造业务,如焊接、热处理、机械加工检验和组装等。夹具提供工具指导元素如钻灌木。他们直接工具c站立位的工件。夹具很少夹在机表,因为它必须移动夹具在桌子上对齐各种衬套在跳汰机与机主轴。8.2AdvantagesofJigsandFixtures8.2工装夹具的优点Productivity.Jigsandfixtureseliminateindividualmarking,positioningandfrequentchecking,whichreducesoperationtimeandincreaseproductivity.生产力。工装夹具消除个人标记、定位和频繁的检查,这样可以减少操作时间和提高生产力。Interchangeability.Jigsandfuturesfacilitateuniformqualityinmanufacture.Thereisnoneedforselectiveassembly.Anypartofmachinefitsproperlyinassemblyandallsimilarcomponentsareinterchangeable可交换性。夹具和期货促进统一的质量在制造。没有必要选择装配。任何机器的一局部适宜在大会和所有类似的组件是可互换的Skillreduction.Jigsandfixturessimplifylocatingandclampingoftheworkpieces.技能复原。工装夹具定位和夹紧的简化工件。Toolguidingelementsensurecorrectpositionofthetoolswithrespecttotheworkpieces.确保正确的工具指导元素位置的工具对于工件。Thereisnoneedforskillfulsettingoftheworkpieceoftool.Anyaveragepersoncanbetrainedtousejigsandfixtures,thereplacementofaskilledworkmanwithunskilledlaborcaneffectsubstantialsavinginlaborcost.不需要熟练的设置的工件的工具。任何人均可以被训练使用工装夹具,更换一个熟练的工匠和不熟练工人可以大大减少劳动力本钱效果。Costreduction.Higherproductionrate,reductioninscarp,easyassemblyandsavingsinlaborcostsresultinsubstantialreductioninthecostofworkpiecesproducedwithjigsandfixtures.降低本钱。更高的产量,减少崖、易装配和储蓄在劳动力本钱导致大幅削减本钱的零件生产工装夹具。8.3TMLocationofTheWorkpieceTM8.3位置的工件AbodythatiscompletelyfreeinspacehastwelvedegreesoffreedomshowninFig.8.l.身体是完全免费的空间有十二个自由度显示在图8l。ItcanrotateaboutorhavelinearmovementalongeachofthethreemutuallyperpendicularaxesXX.YYorIZ,soithassixfreedomsofrotationandsixfreedomsoftranslation.[2]它可以旋转或有线性运动沿着每个三个互相垂直的轴XX。YY或者工业区,所以它有6个自由度的旋转和六个自由翻译[2]。Whenworkpieceislocated,itmustbeconstrainedfrommovinginanydirection,sothesefreedomsareeliminatedorrestrictedtoensurethattheoperatio