機械工程專業(yè)英語-翻譯

Chapter55.1IntroductionConventionalmachiningisthegroupofmachiningoperationsthatusesingle-ormulti-pointtoolstoremovematerialintheformofchips.Metalcuttinginvolvesremovingmetalthroughmachiningoperations.Machiningtraditionallytakesplaceonlathes,drillpresses,andmillingmachineswiththeuseofvariouscuttingtools.Mostmachininghasverylowset-upcostcomparedwithforming,molding,andcastingprocesses.However,machiningismuchmoreexpensiveforhighvolumes.Machiningisnecessarywheretighttolerancesondimensionsandfinishesarerequired.5.1譯文傳統(tǒng)機械加工是一組利用單刃或者多刃刀具以切屑形式去除材料的加工方式。金屬切削意味著通過機械加工去除金屬。傳統(tǒng)的機械加工都是利用不同的刀具在車床、鉆床和銑床上進行的。與成型加工、鍛壓和鑄造工藝相比，大多數(shù)機械加工的生產(chǎn)準(zhǔn)備本錢都較低，然而如果是大批量生產(chǎn)，其本錢要高得多。當(dāng)對零件的尺寸公差和光潔度要求較高時，機械加工是很有必要的。5.2TurningandLatheTurningisoneofthemostcommonofmetalcuttingoperations.Inturning,aworkpieceisrotatedaboutitsaxisassingle-pointcuttingtoolsarefedintoit,shearingawayexcessmaterialandcreatingthedesiredcylindricalsurface.Turningcanoccuronbothexternalandinternalsurfacestoproduceanaxially-symmetricalcontouredpart.Partsrangingfrompocketwatchcomponentstolargediametermarinepropellershaftscanbeturnedonalathe.Apartfromturning,severalotheroperationscanalsobeperformedonlathe.axially['?ksi?li]adv.軸向地symmetrical[si'metrik?l]a.對稱的cylindrical[si'lindrikl]a.圓柱形的contoured['k?ntu?d]a.顯示輪廓的，與某種形體輪廓相吻合的譯文:在金屬切削加工操作中，車削是最常見的一種。在車削過程中，工件繞其軸線回轉(zhuǎn)，單刃車刀沿工件進給，切除掉多余的材料，最后形成要求的圓柱形外表。車削可以加工外面和內(nèi)外表以形成具有軸對稱的成形工件。從懷表的零件到大直徑的船用螺旋槳軸都可以在車床上加工。除了車削，還有另外幾種加工操作都可以在車床上進行。Boringandinternalturning.Boringandinternalturningareperformedontheinternalsurfacesbyaboringbarorsuitableinternalcuttingtools.Iftheinitialworkpieceissolid,adrillingoperationmustbeperformedfirst.Thedrillingtoolisheldinthetailstock,andthelatteristhenfedagainsttheworkpiece.Whenboringisdoneinalathe,theworkusuallyisheldinachuckoronafaceplate.Holesmaybeboredstraight,tapered,ortoirregularcontours.Boringisessentiallyinternalturningwhilefeedingthetoolparalleltotherotationaxisoftheworkpiece.譯文:利用鏜桿或適宜的內(nèi)圓車刀可以進行鏜削和車內(nèi)圓。如果工件毛坯是實心的，首先要鉆孔。鉆頭安裝在尾架上，后者向工件進給。如果在車床上進行鏜削加工，工件通常裝夾在卡盤或者花盤上。鏜出的孔可以是直孔、錐孔或者不規(guī)那么輪廓。當(dāng)將刀具沿工件的回轉(zhuǎn)軸線平行進給時，鏜削實際上就是車內(nèi)圓。Facing.Facingistheproducingofaflatsurfaceastheresultofatool’sbeingfedacrosstheendoftherotatingworkpiece.Unlesstheworkisheldonamandrel,ifbothendsoftheworkaretobefaced,itmustbeturnedaroundafterthefirstendiscompletedandthenthefacingoperationrepeated.Thecuttingspeedshouldbedeterminedfromthelargestdiameterofthesurfacetobefaced.Facingmaybedoneeitherfromtheoutsideinwardorfromthecenteroutward.Ineithercase,thepointofthetoolmustbesetexactlyattheheightofcenterofrotation.Becausethecuttingforcetendstopushthetoolawayfromthework,itisusuallydesirabletoclampthecarriagetothelathebedduringeachfacingcuttopreventitfrommovingslightlyandthusproducingasurfacethatisnotflat.Inthefacingofcastingorothermaterialsthathaveahardsurface,thedepthofthefirstcutshouldbesufficienttopenetratethehardmaterialtoavoidexcessivetoolwear.mandrel['m?ndr?l]n.車床心軸clamp[kl?mp]v.夾緊，夾住carriage[‘k?rid?]n.大刀架，拖板penetrate['penitreit]v.穿透，滲透toolwear刀具磨損譯文:車端面可以加工出一個平面，它是當(dāng)車刀沿回轉(zhuǎn)工件的端面橫向進給的結(jié)果。除非工件固定在心軸上，如果工件兩端都要車端面，必須將一端加工完成后，將工件調(diào)頭，重復(fù)進行車端面加工。車削速度必須由所加工外表的最大直徑來決定。車端面可以由外向內(nèi)也可以由中心向外進行。無論哪種情況，刀尖必須準(zhǔn)確地與回轉(zhuǎn)中心對正。由于切削力有將車刀推離工件的趨勢，通常最可行的就是在車端面時將拖板卡緊在床身上以防止車刀輕微移動造成加工外表不平整。在對具有硬質(zhì)外表的鑄件或其他材料進行車端面加工時，首次切深要足以穿透硬質(zhì)材料從而防止過度的刀具磨損。Parting.Partingistheoperationbywhichonesectionofaworkpieceisseveredfromtheremainderbymeansofcutofftool.Becausecuttingtoolsarequitethinandmusthaveconsiderableoverhang,thisprocessislessaccurateandmoredifficult.Thetoolshouldbesetexactlyattheheightofaxisofrotation,bekeptsharp,haveproperclearanceangles,andbefedintotheworkpieceataproperanduniformfeedrate.remainder[ri'meind?]剩余物，余數(shù)overhang['?uv?'h??]vt.懸于...之上n.伸出;突出uniform['ju:nif?:m]a.相同的,一致的n.制服;軍服clearanceangles后角譯文:切斷是一種利用切斷刀〔割刀〕將工件的一局部與其剩余局部脫離的加工方法。由于切斷刀非常薄而且處于懸臂狀態(tài)，因此這種加工方法不太精確而且加工起來常常比擬困難。切斷刀必須準(zhǔn)確地對正回轉(zhuǎn)軸，保持鋒利，具有適宜的后角，以適宜、不變的進給率沿工件進給。Threading.Threadingcanbeconsideredasturningsincethepathtobetravelledbythecuttingtoolishelical.However,therearesomemajordifferencesbetweenturningandthreading.Whileinturning,theinterestisingeneratingasmoothcylindricalsurface,inthreadingtheinterestisincuttingahelicalthreadofagivenformanddepthwhichcanbecalculatedfromtheformulae.譯文:車螺紋可以看作是車削，只是車刀所形成的加工軌跡是螺旋線。但二者也存在一些不同之處。車削主要考慮能否生成光滑的圓柱形外表，而車螺紋注重的是能否切出具有按公式計算出來的規(guī)定形狀和深度的螺旋線。Therearetwobasicrequirementsforthreadcutting.? Anaccuratelyshapedandproperlymountedtoolisneededbecausethreadcuttingisaform-cuttingoperation.Theresultingthreadprofileisdeterminedbytheshapeofthetoolanditspositionrelativetotheworkpiece.? Thesecondbyrequirementisthatthetoolmustmovelongitudinallyinaspecificrelationshiptotherotationofworkpiece,becausethisdeterminestheleadofthethread.Thisrequirementismetthroughtheuseoftheleadscrewandthesplitunit,whichprovidepositivemotionofcarriagerelativetotherotationofspindleform-cuttingoperation成形加工longitudinally[l?:?d?i'tju:din?li]adv.縱向leadscrew絲杠splitunit開合機構(gòu)譯文:車螺紋有兩個根本要求：首先，由于車螺紋是一種成形加工，因此車刀必須具有準(zhǔn)確的形狀而且要安裝適宜。所切出的螺紋外形是由車刀形狀和它與工件的相對位置決定的。其次，車刀的縱向進給與工件的回轉(zhuǎn)運動具有特定的關(guān)系，因此這決定了螺紋的導(dǎo)程。這個條件可以通過采用絲杠和開合機構(gòu)得到滿足，它們可以實現(xiàn)拖板相對于主軸回轉(zhuǎn)運動的精確可靠的運動1.Enginelathes普通車床2.Verticallathes立式車床3.Turretlathes轉(zhuǎn)塔車床5.Contouringlathes仿形車床6.Universallathes萬能車床Lathebedisfoundationoftheenginelathe,whichheavy,ruggedcastingismadetosupporttheworkingpartsofthelathe.Thesizeandmassofthebedgivestherigiditynecessaryforaccurateengineeringtolerancesrequiredinmanufacturing.Ontopofthebedaremachinedslidewaysthatguideandalignthecarriageandtailstock,astheyaremovefromoneendofthelathetotheother.ruggedadj.健壯，鞏固massn.質(zhì)量slidewaysn.導(dǎo)軌床身是普通車床的根底，它是由沉重而鞏固的鑄件制作而成的，其目的是為了支撐車床的工作部件。床身的尺寸和質(zhì)量要使車床具有足夠的剛性以保證制造過程中獲得所需的工程公差。床身上的導(dǎo)軌可以引導(dǎo)和對準(zhǔn)拖板和尾座，使它們可以從車床的一端移動到另一端。? Headstockisclampedatopthebedatleft-handendofthelatheandcontainsthemotorthatdrivesthespindlewhoseaxisisparalleltotheguidewaysthroughaseriesofgearshousedwithinthegearbox.Thefunctionofgearboxistogenerateanumberofdifferentspindlespeeds.? atopadv.在(…)頂上? gearbox齒輪箱床頭箱〔主軸箱〕緊固在床身上面的左端，內(nèi)裝有電機，它通過變速箱內(nèi)的一組齒輪來驅(qū)動主軸轉(zhuǎn)動，主軸的軸線平行于導(dǎo)軌。變速箱的功能是可以產(chǎn)生不同的主軸轉(zhuǎn)速。? Aspindlegearismountedontherearofthespindletotransmitpowerthroughthechangegearstothefeedingboxthatdistributesthepowertotheleadscrewforthreadingortothefeedrodforturning.? ontherearof在…的尾部? changegears掛輪? leadscrew絲杠? feedrod光杠主軸齒輪安裝在主軸的尾部，通過掛輪把動力傳遞到進給箱，如果是車螺紋，進給箱將動力分配到絲杠上；如果是車削，就將動力分配到光杠上。? Thespindlehasathroughholeextendinglengthwisethroughwhichbarstockscanbefedifcontinuousproductionisused.Theholecanholdaplainlathecenterbyitstaperedinnersurfaceandmountachuck,afaceplateorcolletbyitsthreadedoutersurface.? tapern.坡度，錐形v.錐度加工? colletn.夾頭主軸有一個縱向通孔，如果連續(xù)加工棒料，通孔就用來實現(xiàn)棒料的送料。這個通孔具有一個內(nèi)錐面，可以安裝普通車床的中心頂尖。主軸的外外表車有螺紋，可以安裝卡盤，花盤或夾頭。CarriageassemblyisactuallyanH-shapedblockthatsitsacrosstheguidewaysandinfrontoflathebed.Thefunctionofthecarriageistocarryandmovethecuttingtoollongitudinally.Itcanbemovedbyhandorbypowerandcanbeclampedintopositionwithalockingnut.Thecarriageiscomposedofthecrossslide,compoundrest,toolsaddle,andapron.拖板組件實際上是一個H形的鑄件，位于床身的前端并橫跨在導(dǎo)軌上。拖板的功能帶動刀具縱向移動，這個可以通過手動或者自動完成。利用鎖緊螺母可以將其卡緊在所需位置。拖板組件由橫拖板，小刀架，刀架鞍板和溜板箱組成。? Thecrossslideismountedonthedovetailguidewaysonthetopofthesaddleanditmovedbackandforthat90°totheaxisofthelathebythecrossslideleadscrew.Theleadscrewcanbehandorpoweractivated.? dovetail燕尾槽橫拖板安裝在刀架鞍板上部的燕尾槽導(dǎo)軌上。它利用橫拖板絲杠于車床軸線成90度夾角的方向上前后移動。絲杠可以手動或者自動驅(qū)動。? Thecompoundrestismountedonthecrossslideandcanbeswiveledandclampedatanyangleinahorizontalplane.Thecompoundistypicallyusedforcuttingchamfersortapers,butmustalsobeusedwhencuttingthread.Thecompoundrestcanonlybefedbyhand.Thereisnopowertocompoundrest.Thecuttingtoolandtoolholderaresecuredinthetoolpostwhichismounteddirectlytothecompoundrest.? swivel['sw?v?l]v.旋轉(zhuǎn)小刀架安裝在橫拖板上，它可以在水平面內(nèi)轉(zhuǎn)動或夾緊在任意角度位置。小刀架主要用來倒角和加工錐面，在車削螺紋時也必須用到小刀架。小刀架只能手動進給，沒有動力傳到小刀架上。刀具和刀夾被卡緊在直接安裝在小刀架上的刀座上。ThetoolsaddleisanHshapedcastingmountedonthetopoftheguidewaysandhousesthecrossslideandcompoundrest.Itmakespossiblelongitudinal,crossandangularfeedingofthetoolbit.? 刀架鞍板是一個安裝在導(dǎo)軌上部的H形鑄件，容納有橫拖板和小刀架。它可以實現(xiàn)刀尖的縱向、橫向和斜向進給。Theapronisattachedtothefrontofthecarriageandcontainsthegearsandfeedclutcheswhichtransmitmotionfromthefeedrodorleadscrewtocarriageandcrossslide.Whencuttingscrewthreads,powerisprovidedtothegearboxoftheapronbytheleadscrew.Inallotherturningoperations,itisthefeedrodthatdrivesthecarriage.? 溜板箱位于拖板的前端，里面裝有齒輪和將運動從光杠或絲杠傳遞至拖板或橫向拖板的進給離合器。當(dāng)切制螺紋時，動力通過絲杠傳遞到溜板箱中的變速齒輪箱。在其它車削加工時，依靠光杠來驅(qū)動拖板。? Tailstockiscomposedofalowbaseandthemovablepartofthetail-stockproper,thetransverseadjustmentsbeingmadewithacrossscrewfurnishedwithasquarehead.Thetwopartsareholdtogetherbytheholding-downboltswhichsecurethetailstocktothebed.? transverseadj.橫向的，橫切的；n.橫軸? holding-downbolts壓緊螺栓尾座由底座和尾座體的可移動部件組成。課移動部件的橫向調(diào)整有帶有四方頭的橫向絲杠來完成。底座和可移動局部通過壓緊螺栓連接在一起并將尾座固定在床身上。Chapter66.1Traditionalorconventionalmachining,suchasturning,milling,andgrindingetc.，usesmechanicalenergytoshearmetalagainstanothersubstancetocreateholesorremovematerial.Non-traditionmachiningprocessesaredefinedasagroupofprocessesthatremoveexcess傳統(tǒng)或傳統(tǒng)的加工,如車削、銑削、磨削等,使用機械能剪切金屬反對另一種物質(zhì)來創(chuàng)立洞或刪除材料。非傳統(tǒng)加工過程被定義為一組進程,去除多余materialbyvarioustechniquesinvolvingmechanical,thermal,electricalorchemicalenergyorcombinationsoftheseenergiesbutdonotuseasharpcuttingtoolasitisusedintraditionalmanufacturingprocesses.[1]材料的各種技術(shù)涉及機械、熱、電力或化學(xué)能源或組合這些能量但不使用鋒利的刀具,因為它是用在傳統(tǒng)的制造過程。[1]Extremelyhardandbrittlematerialsarcdifficulttobemachinedbytraditionalmachiningprocesses.Usingtraditionalmethodstomachinesuchmaterialsmeansincreaseddemandfortimeandenergyandthereforeincreasesincosts;insomecasestraditionalmachiningmaynotbefeasible.Traditionalmachiningalsoresultsintoolwearandlossofqualityintheproductowingtoinducedresidualstressesduringmachining.極高的硬度、脆性材料電弧很難通過傳統(tǒng)加工過程的加工。使用傳統(tǒng)方法來機這樣的材料意味著需求增加的時間和精力,因此增加的本錢;在某些情況下傳統(tǒng)加工可能不可行。傳統(tǒng)的加工刀具的磨損,也會導(dǎo)致失去質(zhì)量的產(chǎn)品由于誘導(dǎo)剩余應(yīng)力在加工過程中。Non-traditionalmachiningprocesses,alsocalledunconventionalmachiningprocessoradvancedmanufacturingprocesses,areemployedwheretraditionalmachiningprocessesarenotfeasible,satisfactoryoreconomicalduetospecialreasonsasoutlinedbelow:非傳統(tǒng)加工過程,也稱為非常規(guī)加工過程或先進的生產(chǎn)工藝,采用傳統(tǒng)加工過程不可行,滿意或經(jīng)濟因特殊原因如下所示:1.Verybardfragilematerialsdifficulttoclampfortraditionalmachining;1。非常脆弱的材料很難夾巴德傳統(tǒng)加工;2.Whentheworkpieceistooflexibleorslender,2。當(dāng)工件太靈活或苗條,3.Whentheshapeofthepartistoocomplex;3。當(dāng)形狀的局部是過于復(fù)雜;4.Partswithoutproducingbunsorinducingresidualstresses.4。局部沒有生產(chǎn)面包或誘導(dǎo)剩余應(yīng)力。Traditionalmachiningcanbedefinedasaprocessusingmechanical(motion)energy.傳統(tǒng)加工可以被定義為一個流程使用機械(運動)能量。Non-traditionalmachiningutilizesotherformsofenergy;thethreemainformsofenergy非傳統(tǒng)加工利用其他形式的能源;三種主要形式的能量usedinnon-traditionalmachiningprocessesareasfollows:用于非傳統(tǒng)加工過程如下:1.Thermalenergy;1。熱能;2.Chemicalenergy-,2?；瘜W(xué)能源-,3.Electricalenergy.3。電能。Severaltypesofnon-traditionalmachiningprocesseshavebeendevelopedtomeetextrarequiredmachiningconditions.Whentheseprocessesareemployedproperly,theyoffermanyadvantagesovertraditionalmachiningprocesses.Thecommonnon-traditionalmachiningprocessesaredescribedinthefollowingsection.幾種類型的非傳統(tǒng)加工過程已經(jīng)被開發(fā)出來,以滿足額外的要求加工條件。當(dāng)這些流程是正確使用,他們提供了許多優(yōu)點比傳統(tǒng)的加工過程。常見的非傳統(tǒng)加工過程是下一節(jié)描述。6.2ElectricalDischargeMachining(EDM)6.2電火花加工(EDM)Electricaldischargemachining(EDM)sometimesiscolloquiallyreferredtoassparkmachining,sparkeroding,burning,diesinkingorwireerosion.Itisoneofthemostwidelyusednon-traditionalmachiningprocesses.ThemainattractionofEDMovertraditionalmachiningprocessessuchasmetalcuttingusingdifferenttoolsandgrindingisthatthistechniqueutilizesthermoelectricprocesstoerodeundesiredmaterialsfromtheworkpiecebyaseriesofrapidlyrecurringdiscrete-electricalsparksbetweenworkpieceandelectrode.[2]電火花加工(EDM)有時是通俗地稱為電火花加工、電火花侵蝕,燃燒,開?；蜾摻z侵蝕。這是一個最廣泛使用的非傳統(tǒng)加工過程。主要的吸引力比傳統(tǒng)的電火花加工過程,如金屬切削使用不同的工具和磨削是這種技術(shù)利用熱電過程侵蝕無用的材料工件的一系列迅速反復(fù)出現(xiàn)的離散-電火花工件和電極之間。[2]Thetraditionalmachiningprocessesrelyonhardertoolorabrasivematerialtoremovethesoftermaterialwhereasnon-traditionalmachiningprocessessuchasEDMuseselectricalsparkorthermalenergytoerodeunwantedmaterialinordertocreatedesiredshapes.So,thehardnessofthematerialisnolongeradominatingfactorforEDMprocess.傳統(tǒng)的加工流程依賴?yán)щy工具或研磨材料去除軟材料而非傳統(tǒng)加工如EDM使用電火花或熱能侵蝕多余的材料以創(chuàng)立所需的形狀。所以,硬度的材料不再是一個主要因素電火花放電加工。EDMremovesmaterialbydischarginganelectricalcurrent,normallystoredinacapacitorbank,acrossasmallgapbetweenthetool(cathode)andtheworkpiece(anode)typicallyintheorderof50volts/l0amps.AsshowninFig-6.1,atthebeginningofEDMoperation,ahighvoltageisappliedacrossthenarrowgapbetweentheelectrodeandtheworkpiece.Thishighvoltageinducesanelectricfieldintheinsulatingdielectricthatispresentinnarrowgapbetweenelectrodeandworkpiece.Thiscauseconductingparticlessuspendedinthedielectrictoconcentrateatthepointsofstrongestelectricalfield.Whenthepotentialdifferencebetweentheelectrodeandtheworkpieceissufficientlyhigh,thedielectricbreaksdownandatransientsparkdischargesthroughthedielectricfluid,removingsmallamountofmaterialfromtheworkpiecesurface.Thevolumeofthematerialremovedpersparkdischargeistypicallyintherangeof10-5to10-6mm3.Thegapisonlyafewthousandthsofaninch,whichismaintainedataconstantvaluebytheservomechanismthatactuatesandcontrolsthetoolfeed.除材料的電火花加工放電電流,通常存儲在電容器銀行,在一個小差距工具(陰極)和工件(陽極)通常在訂單50伏特/10安培。圖6所示。1,開始時,一個高壓電火花加工操作是應(yīng)用在狹窄的電極之間的差距和工件。這個高電壓產(chǎn)生電場在絕緣介質(zhì)中存在的差距和工件之間的狹窄電極。這導(dǎo)致導(dǎo)電粒子懸浮在介質(zhì)集中點的最強的電場。當(dāng)潛在的區(qū)別和工件的電極是足夠高,電介質(zhì)分解和瞬時放電通過電介質(zhì),消除少量的材料從工件外表。材料去除的體積每火花放電通常在10-5到10-6的范圍mm3。這個差距只有幾英寸的秒這個級別,這是維持在一個恒定值由伺服機構(gòu),促動和控制工具進給。Chapter77.1Introduction7.1引入Qualityandaccuracyaremajorconsiderationsinmakingmachinepartsorstructures.質(zhì)量和準(zhǔn)確性是主要的考慮因素在制造機零件或結(jié)構(gòu)。Interchangeablepartsrequireahighdegreeofaccuracytofittogether.Withincreasingaccuracyorlessvariationinthedimension,thelaborandmachineryrequiredtomanufactureapartismorecostintensive.[l]Anymanufacturershouldhaveathoroughknowledgeofthetolerancestoincreasethequalityandreliabilityof'amanufacturedpartwiththeleastexpense.具有互換性的零件需要一個高精確度來組裝在一起。隨著準(zhǔn)確性或更少的變異在尺寸、勞動和機械需要制造一個局部是更多的本錢密集型。[]是任何制造商應(yīng)該有一個全面的知識的公差,以便提高質(zhì)量和可靠性的一個制造最少的局部費用。Anengineeringdrawingmustbeproperlydimensionedinordertoconveythedesigner'sintenttotheenduser.Dimensionsofpartsgivenonblueprintsandmanufacturedtothosedimensionsshouldbeexactlyalikeandfitproperly.Unfortunately,itisimpossibletomakethingstoanexactordimension.Mostdimensionshaveavaryingdegreeofaccuracyandameansofspecifyingacceptablelimitationsindimensionalvariancesothatamanufacturedpartwillbeacceptedandstillfunction.Itisnecessarythatthedimensions,shapesandmutualpositionofsurfacesofindividualpartsarekeptwithinacertainaccuracytoachievetheircorrectandreliablefunctioning.Routineproductionprocessesdonotallowmaintenance(ormeasurement)ofthegivengeometricalpropertieswithabsoluteaccuracy.[2]Actualsurfacesoftheproducedpartsthereforedifferfromidealsurfacesprescribedindrawings.Deviationsofactualsurfacesaredividedintofourgroupstoenableassessment,prescriptionandcheckingofthepermittedinaccuracyduringproduction:一個工程圖紙必須得到適當(dāng)?shù)某叽?以傳達設(shè)計者的意圖給最終用戶。維度上給出的局部設(shè)計圖和制造這些維度應(yīng)該完全一樣,恰到好處。不幸的是,它是不可能讓事情一個確切的或維度。大多數(shù)維度有不同程度的準(zhǔn)確性和一種方式來指定可接受的限制在維方差這樣一個人造的局部會被接受,還是函數(shù)。這是必要的,尺寸、形狀和外表的相互位置的各個局部都保持在一定的精度,到達他們的正確和可靠的功能。日常生產(chǎn)過程不允許維護(或測量)給定的幾何屬性以絕對的精度。[2]實際外表產(chǎn)生局部因此不同于理想的外表在圖紙規(guī)定。偏離實際的外表分為四組,使評估、處方和檢查錯誤的允許生產(chǎn)過程中:1.Dimensionaldeviations;1。尺寸偏差;2.Shapedeviations;2。形狀的偏差;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,主要是不可能產(chǎn)生機器零件與絕對尺寸精度。事實上,這是沒有必要的或有用的。這是很充足的,實際的維度的局部是發(fā)現(xiàn)在兩個限制維度和一個容許偏差保持與生產(chǎn),確保正確運轉(zhuǎn)的工程產(chǎn)品。所需的精確度上給定的局部是然后給出的尺寸公差,按照圖紙。生產(chǎn)精度是規(guī)定的關(guān)于產(chǎn)品的功能和經(jīng)濟的生產(chǎn)。校長因子用于設(shè)置一個容忍一個維度應(yīng)該函數(shù)的特性被控制的維度。不必要地緊公差導(dǎo)致高本錢的生產(chǎn)造成更昂貴的制造方法和更高的拒絕利率。7.2Tolerances7.2公差Toleranceisthetotalamountthataspecificdimensionispermittedtovary.Itisthedifferencebetweenthemaximumandtheminimumlimitsforthedimension.Tounderstandtolerances,youshouldunderstandsomeofthedefinitionsassociatedwiththedeterminationofatolerance.Thesedefinitionsmaybegenerallycategorizedasrelatingtosize,allowance,orfit.寬容是一個特定的總量維度是允許不同。它的區(qū)別是最大值和最小值限制為該維度。理解公差,你應(yīng)該了解一些相關(guān)的定義確實定公差。這些定義可能是一般分為大小有關(guān),津貼,或配合。Size.Thesizeofanobjectoritsmateis(mownasnominal,basic,ordesignsize.大小。一個物體的大小或其配偶是(割、根本或隨著名義設(shè)計尺寸。Allowance.Thedifferencebetweenthelargestallowableshaftsizeandthesmallestholediameteristermedastheallowance.[3]Thequalityofthefitischaracterizedbytheallowancevalue.津貼。最大的區(qū)別允許軸尺寸和最小的孔直徑是被稱為津貼。[3]適宜的質(zhì)量特征是津貼值。Fit.clearance,interference,ortransitionfitrefertohowtheobjectfitsanassembly.配合。間隙,干擾,或過渡配合引用的對象如何適合一個裝配。Tospecifythesizeofanobject,wedimensionitwithanominalsize,basicsize,andactualsizeshowninFig.7.1.指定一個物體的大小,我們尺寸用公稱尺寸、根本大小和實際大小顯示在圖71。Nominalsize(basicsize).Itisthedesignationusedforgeneralidentificationandusuallyexpressedincommonfractions.Itisanexacttheoreticalsizeofapartfromwhichlimitdimensionsarecomputed.Thenominalsizeofapartshouldbeselectedfromthepreferreddimensionseriesindicatedbythenationalstandard.(4J(showninFig.7.Ia)公稱尺寸(根本的大小)。它是指定用于通用識別和通常表示在常見的分?jǐn)?shù)。這是一個精確的理論大小的局部限制尺寸計算。名義尺寸應(yīng)該選擇一局部來自首選尺寸系列表示由國家標(biāo)準(zhǔn)。(4j(見圖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許極端大小的一個局部例如,限制一個孔弧1500(下限)和1.501(上限)和一個軸我。499(上限)和1.497(下限),圖7所示。我b。實際大小。這是測量的大小已完成局部,見圖7iclDeviations,allowancerefertosizeallowablevariations.偏差,津貼指大小容許變化。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減去從限制。例如,一個孔尺寸作為,因此上偏差是+0.0004和更低的偏差為-0.0004。Allowance.Theintentionaldifferencebetweenthemaximummateriallimitsofmatingparts.Thisisaminimumclearance(positiveallowance)ormaximuminterference(negativeallowance)betweenmatingparts.津貼。成心差異最大材料限制的配件。這是一個最小間隙(積極的津貼)或最大干擾(負(fù)公差)之間的配件。Tolerancescanbeexpressedineitheroftwoways.公差可表示成兩種方式中的任何一個。BilateralTolerances.Abilateraltoleranceisatoleranceinwhichvariationispermittedinbothdirectionsfromaspecifieddimension.Examp1eis2.00010.0004.Forthisexpression,thedimensionofthepartwouldbepermittedtovarybetween1.996and2.004foratotaltoleranceof0.008.雙邊公差。一個雙邊公差是一個寬容的變化是不被允許在兩個方向上從一個指定的尺寸。Examp1e是2.00010.0004。對于這個表達式,該維度的局部將被允許在1.996和2.004之間不同共0.008的容忍。Theactualsizeoftheobjectmaybelargerorsmallerthanthestatedsizelimitationif實際大小的對象可能大于或小于規(guī)定的大小限制如果therecanbeequalvariationinbothdirections.Theplusandminuslimitationscombineto可以有相等的兩個方向的變化。正負(fù)局限結(jié)合起來formasinglevalue.[5J形成一個單一值。[5jUnilateralTolerances.Aunilateraltoleranceisatoleranceinwhichvariationispermittedonlyinonedirectionfromthespecifieddimension.Exampleis2.OOO;"Forthisexpression.thedimensionofthepartwouldbepermittedtovarybetween2.000and2.008foratotaltoleranceof0.008.單方面的公差。一個單邊公差是一個寬容的變化只能在一個方向從指定的尺寸。例子是2。OOO;“這個表達式。局部的尺寸會允許變化在2.000和2.008之間總公差為0.008。Unilateraltoleranceexpressionhastheadvantagethattheyareeasiertocheckondrawingsandthatthechangeinthetolerancecanbemadewiththeleastdisturbancetootherdimensions.單邊公差表達式的優(yōu)勢在于,他們更容易檢查圖紙,寬容的變化可以用最少的干擾到其他維度。7.3Fits7.3適合Howmatingpartsorassembliesfittogetherwithcomponentpartsisreferredtoasfit,如何交配局部或組件組合在一起以組成局部被稱為健康,whichincludesclearancefit,interferencefit,ortransitionfit,seeFig.7.3.其中包括間隙配合,干預(yù)配合,或過渡配合,見圖7.3。Fitisthegeneralrangeoftightnessresultingfromtheapplicationofaspecificcombinationofallowanceandtolerancesinthedesignofmatingparts.配合是一般的一系列緊張造成的特定組合的應(yīng)用的津貼和公差設(shè)計的配件。Clearancefit.Itisafitenablingaclearancebetweentheholeandshaftinthecoupling.Thelowerlimitsizeoftheholeisgreateroratleastequaltotheupperlimitsizeoftheshaft.間隙配合。這是一個適合啟用一個間隙孔和軸的耦合。下限大小的洞是更大的或至少等于上限大小的軸。Interferencefit.Itisafitalwaysensuringsomeinterferencebetweentheholeandshaftinthecoupling.Theupperlimitsizeoftheboleissmalleroratleastequaltothelowerlimitsizeoftheshaft.干預(yù)配合。這是一個適合總是確保一些干擾洞和軸之間的耦合。大小上限的樹干是較小的或者至少等于下限大小的軸。Transitionfit.Itisafitwhere(dependingontheactualsizesoftheholeandshaft)bothclearanceandinterferencemayoccurinthecoupling.Tolerancezonesoftheholeandshaftpartlyorcompletelyinterfere.過渡配合。這是一個符合(取決于實際大小的孔、軸)兩個間隙和干擾可能發(fā)生耦合。公差帶的孔、軸局部或完全干預(yù)。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.確保工件生產(chǎn)根據(jù)指定的形狀、尺寸和公差,至關(guān)重要的是,工作場所應(yīng)該適當(dāng)?shù)卣业讲⒐潭ㄔ跈C床。[11生產(chǎn)設(shè)備通常workholders與/沒有工具指導(dǎo)/設(shè)置安排這些被稱為工裝夾具。一個fixtureis生產(chǎn)工具,定位、持有和支持工件平安地,以便每個局部是加工在指定的限制。它必須正確定位一個工件在給定的取向?qū)Φ毒呋驕y量設(shè)備,或?qū)α硪粋€組件,比方在大會。這樣的位置必須是不變的,在這個意義上,這個設(shè)備必須夾和平安中,工件的位置,為特定處理操作。裝置通常用于加工(銑床、規(guī)劃、塑造和轉(zhuǎn)動,等等)和其他制造業(yè)務(wù),如焊接、熱處理、機械加工檢驗和組裝等。夾具提供工具指導(dǎo)元素如鉆灌木。他們直接工具c站立位的工件。夾具很少夾在機表,因為它必須移動夾具在桌子上對齊各種襯套在跳汰機與機主軸。8.2AdvantagesofJigsandFixtures8.2工裝夾具的優(yōu)點Productivity.Jigsandfixtureseliminateindividualmarking,positioningandfrequentchecking,whichreducesoperationtimeandincreaseproductivity.生產(chǎn)力。工裝夾具消除個人標(biāo)記、定位和頻繁的檢查,這樣可以減少操作時間和提高生產(chǎn)力。Interchangeability.Jigsandfuturesfacilitateuniformqualityinmanufacture.Thereisnoneedforselectiveassembly.Anypartofmachinefitsproperlyinassemblyandallsimilarcomponentsareinterchangeable可交換性。夾具和期貨促進統(tǒng)一的質(zhì)量在制造。沒有必要選擇裝配。任何機器的一局部適宜在大會和所有類似的組件是可互換的Skillreduction.Jigsandfixturessimplifylocatingandclampingoftheworkpieces.技能復(fù)原。工裝夾具定位和夾緊的簡化工件。Toolguidingelementsensurecorrectpositionofthetoolswithrespecttotheworkpieces.確保正確的工具指導(dǎo)元素位置的工具對于工件。Thereisnoneedforskillfulsettingoftheworkpieceoftool.Anyaveragepersoncanbetrainedtousejigsandfixtures,thereplacementofaskilledworkmanwithunskilledlaborcaneffectsubstantialsavinginlaborcost.不需要熟練的設(shè)置的工件的工具。任何人均可以被訓(xùn)練使用工裝夾具,更換一個熟練的工匠和不熟練工人可以大大減少勞動力本錢效果。Costreduction.Higherproductionrate,reductioninscarp,easyassemblyandsavingsinlaborcostsresultinsubstantialreductioninthecostofworkpiecesproducedwithjigsandfixtures.降低本錢。更高的產(chǎn)量,減少崖、易裝配和儲蓄在勞動力本錢導(dǎo)致大幅削減本錢的零件生產(chǎn)工裝夾具。8.3TMLocationofTheWorkpieceTM8.3位置的工件AbodythatiscompletelyfreeinspacehastwelvedegreesoffreedomshowninFig.8.l.身體是完全免費的空間有十二個自由度顯示在圖8l。ItcanrotateaboutorhavelinearmovementalongeachofthethreemutuallyperpendicularaxesXX.YYorIZ,soithassixfreedomsofrotationandsixfreedomsoftranslation.[2]它可以旋轉(zhuǎn)或有線性運動沿著每個三個互相垂直的軸XX。YY或者工業(yè)區(qū),所以它有6個自由度的旋轉(zhuǎn)和六個自由翻譯[2]。Whenworkpieceislocated,itmustbeconstrainedfrommovinginanydirection,sothesefreedomsareeliminatedorrestrictedtoensurethattheoperatio