外文翻译--链轮的制造方法.doc

GearmanufacturingmethodsAbstractThispaperdealswiththeproductionprocessofthechainwheel.ItDetaileddescriptionofgearplanning,gearshaping,gearhobbing,gearbroaching,gearshaving,geargrinding,andintroducetheteethoftheproductionofavarietyofmethodsandtheusedoccasions.KeyWordsgearplanning,gearshaping,gearhobbing,gearbroaching,gearshaving,geargrinding,GearPlaningtheshapeofthespacebetweengearteethiscomplexandvarieswiththenumberofthegearaswellastoothmodule,somostgearmanufacturingmethodsgeneratethetoothflankinsteadofforming.Gearplaningusesareciprocatingracks,strokinginthedirectionofthehelixonagearwithagradualgenerationoffromastherackeffectivelyrollsroundthegearblank.Therackisrelievedoutofcontactforthereturnstrokeasinnormalshapingorplanning.Ithasthegreatadvantagethatthecuttingtoolsisasamplingrackwithnearingstraightsidedteethwhichcaneasilybegroundaccurately.Thismethodislittleusedforhighproductionbecauseitisrelativelyslowinoperationduetothehightoolandslidemassforjobbingpurposetheslowstrokingratedoesnotmatterandlowtoolcostgiveanadvantagewhereunusualsizesorprofilemodificationarerequired.Gearshapinggearshapingisinherentlysimilartogearplanningbutusesacircularcutterinsteadofarackandtheresultingreductioninthereciprocatinginertiaallowsmuchhigherstrokingspeedmoderngearshaperscuttingcargearscanrunat2000cuttingstrokesperminute.Theshapeofthecutterisroughlythesameasaninvolutegearbutthetipsoftheteetharerounded.Thegeneratingdrivebetweencutterandworkpiecedoesnotinvolvearackorleadscrewsinceonlycircularmotionisinvolvearackorleadscrewsinceonlycircularmotionisinvolved.Thetoolandworkpiecemovetangentiallytypically0.5mmforeachstrokeofthecutter.onthereturnstrokethecuttermustberetractedabout1mmtogiveclearanceotherwisetoolruboccursonthebackstrokeandfailureisrapid.Theadvantageofgearshapingarethatproductionratesarerelativelyhighandthatisthepossibletocutrightuptoashoulder.Unfortunately,forhelicalgears,ahelicalguideisrequiredtoimposearotationalmotiononthestrokingmotionsuchhelicalguidescannotbeproducedeasilyorcheaplysothemethodisonlysuitableforlongrunswithhelicalgearssincespecialcutterandguidesmustbemanufacturedforeacheachdifferenthelixangle.agreatadvantageofgearshapingisitsabilitytocutannulargearssuchasthoserequiredforlargeepicyclicdrives.GearHobbinggearhobbing,themostusedmetalcuttingmethod,usestherackgeneratingprinciplebutavoidsslowreciprocationbymountingmangyracksonarotatingcutter.theracksaredisplacedaxiallytofromagashedworm.Metalremovalratesarehighsincenoreciprocationofhoborworkpieceisrequiredandsocuttingspeeds40m/mincanbeusedforconventionalhobsandupto150m/minforcarbidehobs.Typicallywitha100mmdiameterhobtherotationspeedwillbe100rpmandsoatwentytoothworkpiecewillrotateat5rpm.Eachrevolutionoftheworkpiecewillcorrespondto0.75mmfeedsothehobwilladvancethroughtheworkpieceatabout4mmperminute.forcarproductionroughingmultiplestarthobscanbeusedwithcoarsefeedof3mmperrevolutionsothat100rpmonthecutter,atwostarthoband20toothgearwillgiveafeedrateof30mm/minute.GearBroachingGearbroachingisnotusuallyusedforhelicalgearsbutisusedforinternalsourgearstheprincipleusedofbroachinginthecontextisforinternalsplineswhichcannoteasilydemadebyanyothermethod.Aswithallbroachingthemethodisonlyeconomicforlargequantitiessincesetupcostsarehigh.Gearbroachinggivehighaccuracyandlowsurfaceroughnessbutlikeallcuttingprocessesislimitedtosoftmaterialswhichmustbesubsequentlycasehardenedorhaettreated,givingdistortion.GearShavingGearshavingisusedasfinishingprocessesforgearsinthesoftstate.Theobjectiveistoimprovesurfaceroughnessandprofilebymatingtheroughedoutgearwithacutterwhichwillimproveform.Agearshavingcutterlookslikeagearwhichhasextraclearanceattherootforswarfandcoolantremovalandwhosetoothflankshavebeengroovedtogivecuttingedges.Itisrunmeshwiththeroughgearwithcrossedaxessothatthereisintheorypointcontactwitharelativevelocityalongtheteethgivingscrapingaction.Thegearshavingcuttertootharerelativelyflexibleinbendingandsowillonlyoperateeffectivelywhentheyareindoublecontactbetweentwogearteeth.Thegearandcutteroperateathighrotationspeedswithtraversingoftheworkfaceandabout100micronofmachinesarenotexpensivebutcutteraredelicateanddifficulttomanufactureGearGrindingGeargrindingisextremelyimportantbecauseitisthemainwayhardenedgearsaremachined.whenhighaccuracyisrequireditisnotsufficienttoprecorrectforheattreatmentdistortionandgrindingisthennecessary.Thesimplestapproachtogearisformgrinding.Thewheelprofitisdressedaccuratelytoshaperequiredusingsinglepointdiamondswhicharecontrolledbytemplatescuttotheexactshaperequired.Theprofiledwheelisthenreciprocatedaxiallyalongthegear,whenonetoothshapehasbeenfinished,involvingtypically100micronmetalremoval,thegearisindexedtothenexttoothspace.Thismethodisfairlyslowbutgiveshighaccuracyconsistently.Settingupislengthybecausedifferentdressingtemplatesarechanged.Thefastestgeargrindingmethodusedtheprincipleasgearhobbingbutreplaceagashedandrelivedbyagrindingwheelwhichisarackinsection.Onlysinglestartwormarecutonthewheelbutgearrotationspeedsarehigh,100rpmtypically,soitisdifficulttodesignthedrivesystemtogiveaccuracyandrigidity.Accuracyoftheprocessisreasonablyhighalthoughthereisatendencyforwheelandworkpiecetodeflectvariablyduringgrindingsothewheelfrommayrequiredcompensationformachinedeflectioneffectes.Generationofawormshapeonthegrindingwheelisaslowprocesssinceadressingdiamondmustnotonlyformtherackprofilebuthastomoveaxiallyasthewheelrotates.Oncethewheelhasbeentrued,gearscanbegroundrapidlyuntilredressingisrequired.Thisisthemostpopularmethodforhighproductionrateswithsmallgears.链轮的制造方法摘要这篇文章主要介绍了链轮的制造过程，详细地叙述了刨齿，插齿，滚齿，拉齿，剃齿，磨齿并且详细地介绍了各种制作方法的利弊和运用场合。关键词刨齿，插齿，滚齿，拉齿，剃齿，磨齿链轮齿间的空间形状是复杂的,而且随着齿轮的齿数和模数的不用而变化，因此大多数的链轮制造方法采用战成尺郭而不是成形加工。刨齿是采用往复运动的齿条刀，当齿条刀绕链轮胚料滚切并延其螺旋线方向运动时，齿形就会被逐渐展成。与普通的刨削加工相同，在回程中齿条刀与齿轮脱离接触。这种加工方法最大的好处是，刀具为具有直线齿形或者接近于直线齿形的齿条，其齿面易于进行精确加工。由于刀具和滑枕的质量较大，造成了加工速度和缓慢，因此这种方法几乎不在大批量的加工中应用。对于单件或者少量的齿轮加工而言，缓慢的行程速度带来的影响不大，而且较低的刀具成本对于那些特殊规格和需要进行齿廓修行的齿轮来说则是一个有利条件。插齿，插齿加工在本质上和刨齿加工相类似，只是采用圆形刀具来代替齿条刀。其结果是减少了往复运动的惯性，在加工过程中可以采用比刨削高得多的速度。现代插齿机在加工汽车齿轮时可以达到每分钟2000次切削行程。插齿刀的形状与渐开齿轮大致相同，但是其齿顶是圆的。由于刀具与工件之间的展成传动只包含圆周运动，因此不需要齿条或丝杠。在刀具的每一次行程中，通常刀具和工件的切向移动距为0.5mm，在回程中，刀具必须退让1mm以留出间隙。否则，再退刀时，刀具会擦伤以加工表面，并且加快刀具的磨损。插齿加工的优点是生产率较高和可以将吃插到接近轴肩处。令人遗憾的是，加工斜齿轮时，需要一个能够产生绕插齿运动行程本身旋转的螺旋导轨。这种螺旋导轨不易制造，或者说其制造成本较高。由于对每一种不同螺旋角的齿轮，应该制造不同参数的插齿刀，因此这种方法只适合斜齿轮的大批量加工。插齿加工的一大优点是能够加工诸如大型行星齿轮传动所需的内齿轮。滚齿，滚齿是最常见的金属切削方法。它采用齿条展成原理，但是通过安装在旋转刀上的齿条来避免缓慢的往复运动。这些齿条轴向排布，形成了有缝的蜗杆。由于滚刀和工件均不做往复运动，因此滚齿加工时的金属切削率很高。对于普通滚刀可以采取40m/min的切削速度，对于硬质合金滚刀可采用高达