機械工程英 語

1、1TheLatheItsConstruction車床及其結(jié)構(gòu)Alatheisamachinetoolusedprimarilyfproducingsurfacesofrevolutionflatedges.車床是主要用于生成旋轉(zhuǎn)表面和平整邊緣的機床。Basedontheirpurposeconstructionnumberoftoolsthatcansimultaneouslybemounteddegreeofautomationlat

2、hesmeaccuratelylathetypemachinetoolscanbeclassifiedasfollows:根據(jù)它們的使用目的、結(jié)構(gòu)、能同時被安裝刀具的數(shù)量和自動化的程度，車床—或更確切地說是車床類的機床，可以被分成以下幾類：(1)Enginelathes(2)Toolroomlathes(3)Turretlathes(4)Verticalturningbingmills(5)Automaticlathes(6)Speci

3、alpurposelathes(1)普通車床(2)萬能車床(3)轉(zhuǎn)塔車床(4)立式車床(5)自動車床(6)特殊車床Inspiteofthatdiversityoflathetypemachinetoolstheyallhavecommonfeatureswithrespecttoconstructionprincipleofoperation.Thesefeaturescanbestbeillustratedbyconsideringt

4、hecommonlyusedrepresentativetypetheenginelathe.FollowingisadeionofeachofthemainelementsofanenginelathewhichisshowninFig.11.1.雖然車床類的機床多種多樣，但它們在結(jié)構(gòu)和操作原理上具有共同特性。這些特性可以通過普通車床這一最常用的代表性類型來最好地說明。下面是關于圖11.1所示普通車床的主要部分的描述。Lathebed

5、.Thelathebedisthemainframeinvolvingahizontalbeamontwoverticalsuppts.Itisusuallymadeofgreynodularcastirontodampvibrationsismadebycasting.車床床身：車床床身是包含了在兩個垂直支柱上水平橫梁的主骨架。為減振它一般由灰鑄鐵或球墨鑄鐵鑄造而成。Ithasguidewaystoallowthecarriageto

6、slideeasilylengthwise.Theheightofthelathebedshouldbeappropriatetoenablethetechniciantodohisherjobeasilycomftably.它上面有能讓大拖板輕易縱向滑動的導軌。車床床身的高度應適當以讓技師容易而舒適地工作。Headstock.Theheadstockisfixedatthelefthsideofthelathebedincludest

7、hespindlewhoseaxisisparalleltotheguideways(theslidesurfaceofthebed).Thespindleisdriventhroughthegearboxwhichishousedwithintheheadstock.主軸箱：主軸箱固定在車床床身的左側(cè)，它包括軸線平行于導軌的主軸。主軸通過裝在主軸箱內(nèi)的齒輪箱驅(qū)動。Thefunctionofthegearboxistoprovidean

8、umberofdifferentspindlespeeds(usually6upto18speeds).Somemodernlatheshaveheadstockswithinfinitelyvariablespindlespeedswhichemployfrictionalelectricalhydraulicdrives.齒輪箱的功能是給主軸提供若干不同的速度(通常是6到18速)。有些現(xiàn)代車床具有采用摩擦、電力或液壓驅(qū)動的無級調(diào)速主

9、軸箱。Thespindleisalwayshollowi.e.ithasathroughholeextendinglengthwise.Bar3thespindlethroughatrainofgears.Itisconnectedtoboththefeedrodtheleadscrewenablesingavarietyoffeedseasilyrapidlybysimplyshiftingtheappropriatelevers.現(xiàn)

10、代車床一般在主軸箱下裝備快速變換齒輪箱，通過一系列齒輪由主軸驅(qū)動。它與光桿和絲桿連接，能容易并快速地通過簡單轉(zhuǎn)換適當?shù)牟僮鳁U選擇各種進給。Thequickchangegearboxisemployedinplainturningfacingthreadcuttingoperations.Sincethatgearboxislinkedtothespindlethedistancethattheapron(thecuttingtool)t

11、ravelsfeachrevolutionofthespindlecanbecontrolledisreferredtoasthefeed.快速變換齒輪箱可用于普通車削、端面切削和螺旋切削作業(yè)中。由于這種齒輪箱與主軸相連，主軸每轉(zhuǎn)一圈溜板箱(和切削刀具)運動的距離能被控制，這距離就可以被認為是進給。LatheCuttingTools車床切削刀具Theshapegeometryofthelathetoolsdependuponthepur

12、posefwhichtheyareemployed.車床刀具的形狀和幾何參數(shù)取決于它們的使用目的。Turningtoolscanbeclassifiedintotwomaingroupsnamelyexternalcuttingtoolsinternalcuttingtools.Eachofthesetwogroupsincludethefollowingtypesoftools:車削刀具可以分為兩個主要組別，即外部切削刀具和內(nèi)部切削刀

13、具。這兩組中的每一組都包括以下類型刀具：Turningtools.Turningtoolscanbeeitherfinishingroughturningtools.Roughturningtoolshavesmallnoseradiiareemployedwhendeepcutsaremade.車削刀具：車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小，用于深切削。Ontheotherhfinishingtoolshavelar

14、gernoseradiiareusedfobtainingthefinalrequireddimensionswithgoodsurfacefinishbymakingslightdepthsofcut.Roughturningtoolscanberighthlefthtypesdependinguponthedirectionoffeed.Theycanhavestraightbentoffsetshanks.而精車刀具刀尖半徑較大，

15、用于通過微量進刀深度來獲得具有較好表面光潔度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。Facingtools.Facingtoolsareemployedinfacingoperationsfmachiningplanesideendsurfaces.Therearetoolsfmachininglefthsidesurfacestoolsfrighthsidesurfaces.T

16、hosesidesurfacesaregeneratedthroughtheuseofthecrossfeedcontrarytoturningoperationswheretheusuallongitudinalfeedisused.端面刀具：端面刀具用在端面作業(yè)中加工平板側(cè)面或端部表面，也有加工左右側(cè)表面之分。與一般采用縱向進給的車削作業(yè)相反，那些側(cè)表面通過采用橫向進給產(chǎn)生。Cutofftools.Cutofftoolswhicha

17、resometimescalledpartingtoolsservetoseparatethewkpieceintopartsmachineexternalannulargrooves.切斷刀具：切斷刀具，有時也稱為分割刀具，用于將工件分割成若干部分和或加工外部環(huán)形槽。Threadcuttingtools.Threadcuttingtoolshaveeithertriangularsquaretrapezoidalcuttingedge

18、sdependinguponthecrosssectionofthedesiredthread.Alsotheplaneanglesofthesetoolsmustalwaysbeidenticaltothoseofthethreadfms.螺紋切削刀具：螺紋切削刀具根據(jù)所需螺紋的橫截面，有三角形的、矩形的或梯形的切削刃。同時，這些刀具的平面角必須始終與螺紋形狀的平面角保持一致。Threadcuttingtoolshavestraigh

19、tshanksfexternalthreadcuttingareofthebentshanktypewhencuttinginternalthreads.車外螺紋的螺紋切削刀具為直刀桿，而車內(nèi)螺紋的螺紋切削刀具則是彎刀桿。Fmtools.Fmtoolshaveedgesespeciallymanufacturedtotakeacertainfmwhichisoppositetothedesiredshapeofthemachinedwk