机械工程专业英语施平没翻译课文补充

..4、工程机械概述Aswelookaroundusweseeaworldfullof"things〞:machines,devices,tools;thingsthatwehavedesigned,built,andused;thingsmadeofwood,metals,ceramics,andplastics.Weknowfromexperiencethatsomethingsarebetterthanothers;theylastlonger,costless,arequieter,lookbetter,orareeasiertouse.正如我们环顾四周我们看到世界的"东西〞机器全设备工具;事情我们已经设计建造和使用;木材金属瓷制成的东西和塑料。我们从经历知道有些事情是比别人做得更好他们去年更长本钱更低更安静看起来更好或者更容易使用。理想的情况.Ideally,however,everysuchitemhasbeendesignedaccordingtosomesetof"functionalrequirements〞asperceivedbythedesigners—thatis,ithasbeendesignedsoastoanswerthequestion,"Exactlywhatfunctionshoulditperform"〞Intheworldofengineering,themajorfunctionfrequentlyistosupportsometypeofloadingduetoweight,inertia,pressure,etc.但是每个这样的工程已按设计一些"功能要求〞由设计者认为也就是说它的设计以答复这个问题"终究是什么职能应是执行在工程世界〞频繁的主要功能是如此的支持由于一些装载重量惯性压力式Fromthebeamsinourhomestothewingsofanairplane,theremustbeanappropriatemeldingofmaterials,dimensions,andfasteningstoproducestructuresthatwillperformtheirfunctionsreliablyforareasonablecostoverareasonablelifetime.从我们家中的光束飞机的一个机翼等必须对产品的材料尺寸适当的融合和紧固件生产构造将执行一个较合理的本钱合理的一生中其职能可靠。Inpractice,engineeringmechanicsmethodsareusedintwoquitedifferentways:(1)Thedevelopmentofanynewdevicerequiresaninteractive,iterativeconsiderationofform,size,materials,loads,durability,safety,andcost.(2)Whenadevicefails(unexpectedly)itisoftennecessarytocarryoutastudytopinpointthecauseoffailureandtoidentifypotentialcorrectivemeasures.Ourbestdesignsoftenevolvethroughasuccessiveeliminationofweakpoints.在实践中工程力学方法用于在两个完全不同的方式1.任何新设备的开展需要一个互动形式尺寸材料载荷耐久性平安性和cost.2.迭代审议。当一个设备出现故障往往是要进展一项研究以查明故障原因并找出潜在的纠正措施。我们最优秀的设计往往演变的薄弱环节通过逐步消除。Tomanyengineers,bothoftheaboveprocessescanprovetobeabsolutelyfascinatingandenjoyable,nottomention(attimes)lucrative.对许多工程师上述过程都可以被证明是绝对精彩和愉快的更不用提有利可图。Inany"real〞problemthereisneversufficientgood,usefulinformation;weseldomknowtheactualloadsandoperatingconditionswithanyprecision,andtheanalysesareseldomexact.Whileourmathematicsmaybeprecise,theoverallanalysisisgenerallyonlyapproximate,anddifferentskilledpeoplecanobtaindifferentsolutions.Inthestudyofengineeringmechanics,mostoftheproblemswillbesufficiently"idealized〞topermituniquesolutions,butitshouldbeclearthatthe"realworld〞isfarlessidealized,andthatyouusuallywillhavetoperformsomeidealizationinordertoobtainasolution.在任何"真正〞的问题从来就没有足够好的有用的信息我们很少知道实际的载荷和准确操作的任何条件准确的分析很少。虽然我们可以准确的数学综合分析一般只是近似不同技能的人可以得到不同的解决方案。在工程力学研究中大多数问题都将得到充分的"理想化〞允许独特的解决方案但应该清楚"现实世界〞远不如理想而且你通常会在命令必须执行一些理想化获得一个解决方案。Thetechnicalareaswewillconsiderarefrequentlycalled"statics〞and"strengthofmaterials,〞"statics〞referringtothestudyofforcesactingonstationarydevices,and"strengthofmaterials〞referringtotheeffectsofthoseforcesonthestructure(deformations,loadlimits,etc.).在技术领域中我们将考虑的是通常称为"静〞与"材料力学〞"静〞指的是对固定设备作用力学风和"材料力学〞指的是这些部队在构造上的影响。Whileagreatmanydevicesarenot,infact,static,themethodsdevelopedhereareperfectlyapplicabletodynamicsituationsiftheextraloadingsassociatedwiththedynamicsaretakenintoaccount(weshallbrieflymentionhowthisisdone).static尽管许多设备都没有事实上静态的这里开发的方法是完全适用于动态的情况如果与动态相关联的额外负荷考虑。.Wheneverthedynamicforcesaresmallrelativetothestaticloadings,thesystemisusuallyconsideredtobe每当动态势力相对较小的静态负荷系统通常被认为是静态的。Inengineeringmechanics,wewillappreciatethevarioustypesofapproximationsthatareinherentinanyrealproblem:Primarily,wewillbediscussingthingswhicharein"equilibrium,〞i.e.,notaccelerating.However,ifwelookcloselyenough,everythingisaccelerating.Wewillconsidermanystructuralmemberstobe"weightless〞—buttheyneverare.Wewilldealwithforcesthatactata"point〞—butallforcesactoveranarea.Wewillconsidersomepartstobe"rigid〞—butallbodieswilldeformunderload.在工程力学我们赞赏逼近了在任何类型的固有的各种现实问题首先我们将要讨论的事情这是在"均衡〞即没有加速。但是如果我们仔细观察的话一切都正在加速。我们会考虑很多构件是"失重〞但是他们从来没有的。我们将按照部队的这种行为在一个"点〞但所有力量在一个区域的行为。我们会考虑的某些局部"刚性〞但所有机构将在负荷下变形。Wewillmakemanyassumptionsthatclearlyarefalse.Buttheseassumptionsshouldalwaysrendertheproblemeasier,moretractable.Youwilldiscoverthatthegoalistomakeasmanysimplifyingassumptionsaspossiblewithoutseriouslydegradingtheresult.我们会作出这样的假设显然是错误的。但是这些假设应始终呈现的问题更容易更容易处理。你会发现他们的目标是使尽可能多的简化假设没有严重退化的结果。Generallythereisnoclearmethodtodeterminehowpletely,orhowprecisely,totreataproblem:Ifouranalysisistoosimple,wemaynotgetapertinentanswer;ifouranalysisistoodetailed,wemaynotbeabletoobtainanyanswer.Itisusuallypreferabletostartwitharelativelysimpleanalysisandthenaddmoredetailasrequiredtoobtainapracticalsolution.一般来说没有明确的方法来确定如何彻底或如何准确地说对待一个问题如果我们的分析过于简单我们可能无法获得相关的答案如果我们的分析过于详细我们可能无法获得任何答案。它通常是最好先从相对简单的分析然后添加更多的细节因为需要得到实际的解决方法。Duringthepasttwodecades,therehasbeenatremendousgrowthintheavailabilityofputerizedmethodsforsolvingproblemsthatpreviouslywerebeyondsolutionbecausethetimerequiredtosolvethemwouldhavebeenprohibitive.Atthesametimethecostofputercapabilityandusehasdecreasedbyordersofmagnitude.Weareexperiencinganinfluxof"personalputers〞oncampus,inthehome,andinbusiness.在过去的二十年来一直在为解决以往无法解决的问题进展电脑化方法的途径巨大增长因为所需的时间来解决这些问题将被制止。在同一时间计算机能力和使用本钱下降了几个数量级。我们正经历一个"个人电脑〞校园涌入在家里和商业活动中。26、车床Thegeneralcharacteristicsofthemachinetoolsusedincuttingoperationsarereviewedinthistext.Theequipmentcanbeclassifiedindifferentcategoriesdependingontheirfunctionandtheaccessoriesinvolved.Themajorcategoriesaredescribedbelow.在切割操作中使用的机床的一般特征在这篇文章进展阐述。依据功能和所包含的配件设备可分为不同类别。主要类别如下所述。LathesLathesaregenerallyconsideredtobetheoldestmachinetoolsandweredevelopedinthe1750s.Thebasicoperationscarriedoutonalatheareturning,boring,andfacing.车床车床通常被认为是最古老的机床并在1750s产生.车床上进展根本操作有车削镗和端面车削。Thebasicponentsofthemostmonlathe(enginelathe)arethebed,headstock,tailstock,andcarriage.Oneendoftheworkpieceisclampedinachuckthatismountedonthespindle,thespindlerotatesintheheadstock.Theotherendoftheworkpieceissupportedbythetailstock.Theheadstockcontainsthedrivegearsforthespindlespeeds,andthroughsuitablegearingandthefeedrod,drivesthecarriageandcrossslideassembly.Thecarriageprovidesmotionparalleltotheaxisofrotation,andthecrossslideprovidesmotionnormaltoit.Acuttingtool,attachedtoatoolpostandtothecarriage,removesmaterialbytravelingalongthebed.Thecuttingoperationisperformedatacertaindesiredperipheralspeedoftheworkpiece,feedrate,anddepthofcut最常见的车床普通车床的根本组成局部是床身床头尾座和.托架。工件的一端是被一个安装在主轴的夹头夹紧主轴在床头旋转。工件的另一端是由尾座支撑。床头包含主轴转速传动齿轮并通过适当的齿轮和进给杆驱动车架使滑动装配滑动。托架提供运动平行旋转轴横滑板提供了正常的运动。切削刀具连接到一个刀架和托架沿床消除材料。切割操作是按工件所需的一定的外设速度进给速度切削深度运行。Afurtherdevelopmentistheautomaticlathe.Themovementsandcontrolsareactuatedbyvariousmechanicalmeans,suchascamsandnumericalandputercontrol,thusreducinglabororrequiringlessskilledlabor.进一步开展的是自动车床。通过各种机械手段运动和控制更加准确。如凸轮和数控和计算机控制从而减轻了工人的劳动或要求不太熟练的劳动力。Turretlathes(developedinthe1850s)carryoutmultiplecuttingoperations,suchasturning,boring,drilling,threadcutting,andfacing.Variouscuttingtools,usuallyuptosixareinstalledonaturret.Theoperationisquiteversatile.Itmaybeoperatedbyhandorautomaticallyand,oncesetupproperly,itdoesnotrequireskilledlabor.Thereareagreatvarietyofturretlathesavailablefordifferentpurposes.转塔车床在19世纪50年代开发的能够进展了多种切割操作如车削镗钻线切割端面车削。各种切削工具通常在最多六个炮塔上安装。操作相当灵活。它可能是手工操作或自动一旦正确安装它并不需要熟练的劳动力。有种类繁多的炮塔车床可用于不同的目的Screwmachines(thefirstscrewlathewasdevelopedinthe1770s)aredesignedforhighproductionratemachiningofscrewsandsimilarparts.Alltheoperationsareperformedautomaticallywithtoolsattachedtoaspecialturret.Thebarstockisfedautomaticallyaftereachscrewhasbeenmachinedtoafinishedproduct.Thesemachinesmaybeequippedwithsingleormultiplespindlestoreducethecycletimeperpiece.螺杆机在18世纪70年代开发了第一个螺丝车床是专为高产率自动化生产螺钉和类似部件的设计的。所有的操作都由连接到一个特殊的炮塔的工具自动执行。每个螺丝加工成成品后棒料自动送入。这些机器可能会配有单个或多个主轴MillingMachinesTheseareamongthemostversatileandusefulmachinetoolsbecausetheyarecapableofperformingavarietyofcuttingoperations.Thereisalargeselectionofmillingmachines(developedinthe1860s)availablewithnumerousfeatures.Thebasictypesareoutlinedbelow.Knee-and-columntypemillingmachinesarethemostmonandareusedforgeneral-purposemachining.Thespindle,towhichthemillingcutterisattached,maybehorizontal(forslabmilling),orvertical(forfacemilling).铣床铣床是最通用和最有用的工具机因为它们能够执行各种切割操作。有大量的提供众多特性的铣床可供选择在19世纪60年代开发的。根本类型概述如下。升降台式铣床是最常见的用于一般用途的加工。连接铣刀的主轴可水平板坯铣削或垂直面铣。Bed-typemillingmachineshavethetablemountedonabed(replacingtheknee)andcanmoveonlyinthelongitudinaldirection.Thesemachinesaresimpleandrigidlyconstructedandareusedforhigh-quantityproduction.Thespindlesmaybehorizontalorverticalandcanbeofduplexortriplextypes(thatis,withtwoorthreespindlesforsimultaneousmachiningoftwoorthreesurfacesonapart).Othertypesofmillingmachinesarealsoavailable,suchastheplanertypeforheavyworkandmachinesforspecialpurposes床身式铣床上安装一个平台只可以在纵向方向移动。这些机器很简单严格装配并用于高量产。主轴可水平或垂直可以双工或三工类型即有两个或三个主轴同时加工两个或三个局部外表。其他类型的铣削机也可用如用于繁重的工作的龙门式和特殊用途的机器。Amongaccessoriesformillingmachines,oneofthemostwidelyusedistheuniversaldividinghead.Thisisafixturethatrotatestheworkpiecetospecifiedanglesbetweenindividualmachiningsteps.Typicalusesareinmillingpartswithpolygonalsurfacesandinmachininggearteeth.铣床使用最广泛的配件是通用的分度头。这是一个夹具在各个加工步骤使工件旋转到指定角度。典型的用途是加工铣削有多边形外表的零件和加工齿轮齿。PlanersandShapersThesemachinetoolsaregenerallyusedformachininglargeflatsurfacesalthoughothershapes,suchasgrooves,canalsobemachined.Inaplaner,theworkpiecetravelsunderthecross-railequippedwithcuttingtools,whereasinashaperthetooltravelsandtheworkpieceisstationary龙门刨床和牛头刨床这些机床一般用于加工大平面虽然其他形状如凹槽也可以加工。在龙门刨床工件上在装有刀具的下轨移动而在牛头刨床工具移动和工件是固定的。Becauseofthesizeoftheworkpiecesinvolved,planersareamongthelargestmachinetools.Shapersmaybehorizontalorverticalandarealsousedformachiningnotchesandkeyways由于所涉及的工件的大小龙门刨床是位于最大的机床之列。刨边机可水平或垂直也用于加工凹槽和键槽。BroachingMachinesThesemachinespushorpullbroaches,eitherhorizontallyorvertically,togeneratevariousexternalorinternalsurfaces.Theyareofrelativelysimpleconstructionandareactuatedhydraulicallyandhaveonlylinearmotionofthebroach.Becauseofthegreatvarietyofshapesandpartsinvolved,broachingmachinesaremanufacturedinawiderangeofdesignsandsizes.拉床这些机器推或拉拉刀水平或垂直从而加工各种部或外部的外表。他们的构造相对简单液压驱动可实现拉刀只有直线运动。由于涉及的形状和局部种类繁多拉床被制造成各式的设计和尺寸。DrillingMachinesThesemachinesareusedfordrillingholes,tapping,counterboring,reaming,andothergeneral-purposeboringoperations.Theyareusuallyvertical,themostmononebeingadrillpress.Drillingmachinesaremanufacturedinawidevarietyofsizes,fromsimplebenchtypeunitstoradialdrillsandlargeproductionmachineswithmultiplespindles.钻孔机这些机器用于钻孔攻丝锪孔铰孔和其他通用的镗操作。它们通常是垂直的最常见的一种是钻床。钻床制造成种类繁多的尺寸从简单的板凳类型单元到摇臂钻床和有多个主轴的大型生产设备。46课puter-aideddesignCADinvolvestheuseofputerstocreatedesigndrawingsandproductmodels.puter-aideddesignisusuallyassociatedwithinteractiveputergraphicsknownasaCADsystem.计算机辅助设计(CAD)涉及到电脑的使用来创立设计图纸和产品模型。计算机辅助设计通常是与交互式计算机图形学(称为CAD系统)。puter-aideddesignsystemsarepowerfultoolsandareusedinthemechanicaldesignandgeometricmodelingofproductsandponents计算机辅助设计系统是强大的工具,用于产品的机械设计和几何建模和组件InCADthedrawingboardisreplacedbyelectronicinputandoutputdevices.WhenusingaCADsystemthedesignercanconceptualizetheobjecttobedesignedmoreeasilyontheGraphicsscreenandcanconsideralternativedesignsormodifyaparticulardesignquicklytomeetthenecessarydesignrequirementsorchanges.在CAD图纸被电子输入和输出设备。当使用CAD系统中,设计人员可以概念化设计的对象更容易在图形屏幕上,可以考虑替代设计或修改一个特定设计迅速满足必要的设计要求或更改。Thedesignercanthensubjectthedesigntoavarietyofengineeringanalysesandcanidentifypotentialproblemssuchasanexcessiveloadordeflection.Thespeedandaccuracyofsuchanalysesfarsurpasswhatisavailablefromtraditionalmethods.设计师可以设计各种各样的工程分析和可以识别潜在的问题(如过度负荷或偏转)。这种分析的速度和准确度远远超过可以从传统的方法是什么。Draftproductivityrisesdramatically.Whensomethingisdrawnonceitneverhastobedrawnagain.草案生产率大幅上升。当有了一次,它从来没有再画。itcanberetrievedfromalibrary,andcanbeduplicated,stretched,sized,andchangedinmanywayswithouthavingtoberedrawn。Cutandpastetechniquesareusedaslabor-savingaids.它可以从库检索,可以复制,拉伸,大小,改变在许多方面不用redrawn.Cut粘贴技术用作省力艾滋病。CADmakespossiblemultiview2Ddrawingsandthedrawingscanbereproducedindifferentlevelsofreductionandenlargement.CAD使可能的多视图2d图纸,图纸可以复制在不同程度的减少和扩大。Itgivesthemechanicalengineertheabilitytomagnifyeventhesmallestofponentstoascertainifassembledponentsfitproperly.它让机械工程师的能力放大甚至最小的组件来确定如果组装组件配合得当。Partswithdifferentcharacteristicssuchasmovableorstationarycanbeassigneddifferentcolorsonthedisplay.局部具有不同特点,如移动或静止不动的,可以指定不同的颜色显示。Designershaveevenmorefreedomwiththeadventof3-Dpartsandmanipulatetheminendlessvariationstoachievethedesiredresults.设计师有更多自由随着3d局部和操纵他们无穷无尽的变化来获得期望的结果。Throughfiniteelementanalysisstressescanbeappliedtobeaputermodelandtheresultsgraphicallydisplayedgivingthedesignerquickfeedbackonanyinherentproblemsinadesignbeforethecreationofaphysicalprototype.通过有限元分析,压力可以被应用到一个计算机模型,结果以图形方式显示出来,给设计师提供快速反响任何固有的问题在设计物理原型的创立。Inadditiontothedesign’sgeometricanddimensionalfeaturesotherinformationsuchasalistofmaterialsspecificationandmanufacturinginstructionsisstoredintheCADdatabase.Usingsuchinformation,thedesignercanthenanalyzetheeconomicsofalternativedesigns.除了设计的几何和空间特性,其他信息(如材料的清单,规,和生产指令)存储在CAD数据库。使用这些信息,设计师可以分析替代的经济设计。puter-aidedmanufacturing(CAM)involvestheusesofputersandputertechnologytoassistinallthephasesofmanufacturingaproductincludingprocessandproductionplanningmachiningschedulingmanagementandqualitycontrol.puter-aideddesignandputer-aidedmanufacturingareoftenbinedintoCAD/CAMsystems.计算机辅助制造(CAM)涉及计算机和计算机技术的使用,协助生产一个产品的所有阶段,包括过程和生产方案、加工、调度、管理和质量控制。计算机辅助设计和计算机辅助制造通常结合到CAD/CAM系统。Thisbinationallowthetransferofinformationfromthedesignstageintothestageofofplanningforthemanufactureofaproductwithouttheneedtoreenterthedataonpartgeometrymanually.这种组合允许转让信息从设计阶段的阶段,规划产品的生产,而不需要手动重新输入数据部分几何。ThedatabasedevelopedduringCADisstoredthenitisprocessedfurtherbyCAMintothenecessarydataandinstructionsforoperatingandcontrollingproductionmachinerymaterial-handlingequipmentandautomatedtestingandinspectionforproductquality.在CAD开发的数据库存储;然后进一步处理,通过凸轮,到所需的数据和指令操作和控制生产机械、设备来源,自动化测试和检验产品质量。InmachiningoperationsanimportantfeatureofCAD/CAMisitscapabilitytodescribethetoolpathforvariousoperationssuchasNCturningmillinganddrilling.在加工操作中,CAD/CAM的一个重要特性是其能力来描述刀具轨迹的各种操作,如数控车削、铣削和钻孔。Theinstructionsprogramsareputergeneratedandtheycanbemodifiedbytheprogrammertooptimizethetoolpath.计算机生成的指令(程序),他们可以由程序员修改优化刀具轨迹。Theengineerortechniciancanthendisplayandvisuallycheckthetoolpathforpossibletoolcollisionswithfixturesorotherinterferences.Thetoolpathcanbemodifiedatanytimetoacmodateotherpartshapestobemachined.工程师或技术员可以显示和视觉检查刀具轨迹的可能的工具与设备碰撞或其他干扰。工具路径随时可以修改,以适应其他局部形状加工。SometypicalapplicationsofCAD/CAMareaprogrammingforNCCandindustrialrobotsbdesignoftoolsandfixturesandEDMelectodescqualitycontrolandinspectionforinstancecoordinate-measuringmachinesprogrammedonaCAD/CAMworkstationdprocessplanningandschedulingandeplantlayout.一些典型的CAD/CAM的应用是:(a)为数控编程,数控,和工业机器人;(b)设计的工具和夹具和EDMelectodes;(c)质量控制和检查,例如,坐标测量机CAD/CAM工作站程序;(d)工艺规划和调度;(e)工厂的布局。TheemergenceofCAD/CAMhashadamajorimpactonmanufacturingbystandardizingproductdevelopmentandbyreducingdesignefforttryoutandprototypeworkithasmadepossiblesignificantlyreducedcostsandimprovedproductivity.CAD/CAM的出现已经对生产产生重大影响,通过标准化产品开发和减少设计工作,调试,和原型工作;它可能显著降低本钱和提高生产力。Thetwo-engineBoeing777passengerairplaneforexample,wasdesignedpletedbyputerpaperlessdesign.TheplaneisconstructeddirectlyfromtheCAD/CAMsoftwaredevelopedanenhancedCATIAsystemandnoprototypesormockupswerebuiltsuchaswererequiredforpreviousmodels.双引擎的波音777客机,例如,设计完成的计算机(无纸化设计)。飞机构造直接从开发的CAD/CAM软件(一个增强的CATIA系统)和任何原型和模型建立,如需要以前的模型。50课Today,puternumericalcontrolmachinetoolsarewidelyusedinmanufacturingenterprises.puternumericalcontrolistheautomatedcontrolofmachinetoolsbyaputerandputerprogram.今天,计算机数控机床广泛应用于制造企业。计算机数控机床的自动控制是计算机和计算机程序。TheCmachinesstillperformessentiallythesamefunctionsasmanuallyoperatedmachinetoolsbutmovementsofthemachinetoolarecontrolledelectronicallyratherthanbyhand.Cmachinetoolscanproducethesamepartsoverandoveragainwithverylittlevariation.Theycanrundayandnightweekafterweekwithoutgettingtired.Theseareobviousadvantagesovermanuallyoperatedmachinetoolswhichneedagreatdealofhumaninteractioninordertodoanything.数控机器仍执行一样的函数作为手动机床,但机床控制电子的运动,而不是用手。数控机床可以产生一样的局部,一次又一次变化很少。他们可以日夜不停地运转,一周又一周,没有累了。这些明显的优势在手动机床,需要大量的人工交互为了做任何事。ACmachinetooldiffersfromamanuallyoperatedmachinetoolonlyinrespecttothespecializedponentsthatmakeuptheCsystem.TheCsystemcanbefurtherdividedintothreesubsystemscontroldriveandfeedback.AllofthesesubsystemsmustworktogethertoformapleteCsystem.数控机床不同于一个手动机床只有在尊重专业的组件构成的数控系统。数控系统可以进一步分为三个子系统:控制、驱动,和反响。所有这些子系统必须共同努力,形成一个完整的数控系统。1.controlsystem1。控制系统ThecenterpieceoftheCsystemisthecontrol.TechnicallythecontroliscalledthemachinecontrolunitMCUbutthemostmonnamesusedinrecentyearsarecontrollercontrolunitorjustplaincontrol.Thisistheputerthatstoresandreadstheprogramandtellstheotherponentswhattodo.数控系统控制的核心。技术控制称为机控制单元(MCU),但近年来最常用的名字是控制器,控制单元,或者就是简单的控制。这是计算机存储和读取程序,告诉其他组件该做什么。2.Drivesystem.2。驱动系统。Thedrivesystemisprisedofscrewsandmotorsthatwillfinallyturnthepartprogramintomotion.Thefirstponentoftypicaldrivesystemisahigh-precisionleadscrewcalledaballscrewFig.50.1.Eliminatingbacklashinaballscrewisveryimportantfortworeasons.Firsthigh-precisionpositioningcannotbeachievedifthetableisfreetomoveslightlywhenitissupposedtobestationary.Secondmaterialscanbeclimb-cutsafelyifthebacklashhasbeeneliminated.ClimbcuttingisusuallythemostdesirablemethodformachiningonaCmachine.螺丝和汽车的传动系统是由局部程序,最终将变成运动。第一个组件的典型的驱动系统是一种高精度丝杠称为滚珠丝杆(Fig.50.1)。消除反响在滚珠螺杆是非常重要的两个原因。首先,不能实现高精度定位如果表是免费的移动略当它应该是固定的。第二,材料可以平安地同向如果反弹已经消除。爬上切割通常是最可取的方法在数控加工机器。Drivemotorsarethesecondspecializedponentinthedrivesystem.Theturningofthemotorwillturntheballscrewtodirectlycausethemachiningtabletomove.SeveraltypesofelectricmotorsareusedonCcontrolsystemsandhydraulicmotorsarealsooccasionallyused.驱动电机驱动系统中的第二专业组件。电动机的转动将滚珠螺杆直接导致加工表。几种类型的电机是用在数控控制系统和液压马达也偶尔使用。ThesimplesttypeofelectricmotorusedinCpositioningsystemsisthesteppermotorsometimescalledasteppingmotor.Asteppermotorsrotatesafixednumberofdegreeswhenitreceivesanelectricalpulseandthenstopsuntilanotherpulseisreceived.Thesteppingcharacteristicmakessteppermotorseasytocontrol.最简单的类型的电动机用于数控定位系统是步进电机(有时称为步进电机)。步进电机旋转固定数量的度当它收到一个电脉冲,然后停顿,直到接收到一个脉冲。步进特性使步进电机容易控制。ItismoremontouseservomotorsinCsystemstoday.Servomotorsoperatedinasmoothcontinuousmotion—notlikethediscretemovementsofthesteppermotors.Thissmoothmotionl