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Lesson39GearManufacturingMethods•Terminology•Texttour2019/8/51《机械工程专业英语教程》Terminology2019/8/52《机械工程专业英语教程》•Annular•Shapedlikeorformingaring.•环形的，轮状的：形状像环或形成环状。•Annulargear内齿轮,齿圈（也称为internalgear）《机械工程专业英语教程》2019/8/5Helicalgear斜齿轮3•Hob滚刀2019/8/5《机械工程专业英语教程》4•Worm蜗杆•Wormgear•1.Agearconsistingofaspirallythreadedshaftandawheelwithmarginalteeththatmeshintoit•蜗轮蜗杆副•2.Thetoothedwheelofthisgear,awormwheel•蜗轮2019/8/5《机械工程专业英语教程》5•Broach拉刀•Swarf•Finemetallicfilingsorshavingsremovedbyacuttingtool.•小铁屑：用锉或剃等加工方法去除的细小金属屑。2019/8/5《机械工程专业英语教程》6•Dressing•Dressingistheprocessofconditioningworngrainsonthesurfaceofagrindingwheelbyproducingsharpnewedgesongrainssothattheycancutmoreefficiently.•砂轮修整：使砂轮表面磨钝的磨粒上产生新的锋利的切削刃，使其能够更有效地进行切削工作。2019/8/5《机械工程专业英语教程》7GearPlaning（刨齿）Theshapeofthespacebetweengearteethiscomplexandvarieswiththenumberofteethonthegearaswellastoothmodule（模数），somostgearmanufacturingmethodsgeneratethetoothflank(齿腹)insteadofforming（采用展成法加工齿面而不是采用成形法加工）.《机械工程专业英语教程》2019/8/5Texttour8Gearplaningusesareciprocatingrack（往复运动的齿条刀）,stroking（击、打、切）inthedirectionofthehelix（螺旋）onagearwithagradualgenerationofformastherackeffectivelyrollsroundthegearblank(齿轮毛坯)（当齿条刀绕齿轮坯料滚切并沿其螺旋线方向运动时，齿形就会被逐渐展成）.…………Therackisrelievedoutofcontact（脱离接触）forthereturnstrokeasinnormalshapingorplaning（与普通的刨削加工相同）.Ithasthegreatadvantagethatthecuttingtoolisasimplerackwith(nearly)straightsidedteethwhichcaneasilybegroundaccurately(刀具为具有直线齿形或者接近与直线齿形的齿条，其齿面易于进行精确磨削加工).…………Thismethodislittleused(几乎不用)forhighproductionbecauseitisrelativelyslowinoperationduetothehightoolandslidemass(由于刀具和滑枕的质量较大)；forjobbing（重复性很小的工作）purposestheslowstrokingratedoesnotmatterandlowtoolcostsgiveanadvantagewhereunusualsizesorprofilemodificationsarerequired.（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形的齿轮来说则是一个有利的条件）GearShaping（插齿）Gearshapingisinherentlysimilartogearplaning（刨齿加工）butusesacircularcutter（圆形刀具）insteadofarack(齿条刀)andtheresultingreductioninthereciprocatinginertia（运动惯性）allowsmuchhigherstrokingspeeds（行程速度）；moderngearshapers（插齿机）cuttingcargearscanrunat2000cuttingstrokesperminute.Theshapeofthecutterisroughlythesameasaninvolutegear（渐开线齿轮）butthetipsoftheteetharerounded.Thegeneratingdrivebetweencutterandworkpiecedoesnotinvolvearackorleadscrewsinceonlycircularmotionisinvolved（由于刀具与工件之间的展成运动只包含圆周运动，因此不需要齿条或者丝杠）.Thetoolandworkpiecemovetangentially(切向移动)typically0.5mmforeachstrokeofthecutter.Onthereturnstrokethecuttermustberetracted（退让）about1mmtogiveclearanceotherwisetoolruboccursonthebackstroke（退刀）andfailureisrapid.Theadvantagesofgearshapingarethatproductionratesarerelativelyhighandthatitispossibletocutrightuptoashoulder（将齿插到接近轴肩处）.Unfortunately,forhelicalgears（斜齿轮）,ahelicalguide（螺旋导轨）isrequiredtoimposearotationalmotiononthestrokingmotion（需要有一个能够产生绕插齿运动行程本身旋转的螺旋导轨）；…………suchhelicalguidescannotbeproducedeasilyorcheaplysothemethodisonlysuitableforlongrunswithhelicalgears（斜齿轮的大批量加工）sincespecialcuttersandguidesmustbemanufacturedforeachdifferenthelixangle.Agreatadvantageofgearshapingisitsabilitytocutannular（环形的，轮状的）gearssuchasthoserequiredforlargeepicyclicdrives（行星齿轮传动）.GearHobbing（滚齿）Gearhobbing，themostusedmetalcuttingmethod，usestherackgeneratingprinciple（齿条展成原理）butavoidsslowreciprocationbymountingmany“racks”onarotatingcutter（旋转刀具）.The“racks”aredisplacedaxiallytoformagashed（很深的裂缝）worm（这些“齿条”轴向排布，形成了有缝的蜗杆）.Metalremovalratesarehighsincenoreciprocationofhoborworkpiece（滚刀和工件）isrequiredandsocuttingspeedsof40m/mincanbeusedforconventionalhobs（普通滚刀）andupto150m/minforcarbidehobs（硬质合金滚刀）.Typicallywitha100mmdiameterhobtherotationspeedwillbe100rpmandsoatwentytoothworkpiecewillrotateat5rpm.…………Eachrevolutionoftheworkpiecewillcorrespondto0.75mmfeedsothehobwilladvancethroughtheworkpieceatabout4mmperminute.Forcarproductionroughingmultiplestarthobs（多头粗加工滚刀）canbeusedwithcoarsefeedsof3mmperrevolutionsothat100rpmonthecutter,atwo-starthob（双头滚刀）anda20toothgearwillgiveafeedrateof30mm/min.GearBroaching（拉齿）Gearbroachingisnotusuallyusedforhelicalgears（斜齿轮）butisusefulforinternalspurgears（直齿轮）；theprincipleuseofbroachinginthiscontext（在这种情况下）isforinternalsplines（内花键）whichcannoteasilybemadebyanyothermethod.Aswithallbroachingthemethodisonlyeconomicforlargequantitiessincesetupcosts（设备的费用）arehigh.GearBroachinggiveshighaccuracyandlowsurfaceroughness（低表面粗糙度）butlikeallcuttingprocessesislimitedto“soft”materialswhichmustbesubsequently（随后）case-hardenedorheattreated（表面硬化或者热处理），givingdistortion（产生变形）.GearShaving（剃齿）Gearshavingisusedasfinishingprocessesforgearsinthe“soft”state.Theobjectiveistoimprovesurfaceroughnessandprofile（降低齿面粗糙度和改善齿廓形状）bymatingtheroughed-outgearwitha“cutter”whichwillimproveform（通过采用具有较高齿形精度的“刀具”与经过粗加工的齿轮进行啮合）.Agearshavingcutterlookslikeagearwhichhasextraclearance（附加的凹槽）attheroot(forswarfandcoolantremoval细铁屑冷却液排除)andwhosetoothflankshavebeengrooved（开小槽）togivecuttingedges（形成切削刃）.…………Itisruninmeshwiththeroughgearwithcrossedaxes（剃齿刀与经过粗加工的齿轮成交错轴啮合传动）sothatthereisintheorypointcontact（点接触）witharelativevelocityalongtheteeth（沿轮齿）givingscrapingaction（刮削作用）.Thegearshavingcutterteetharerelativelyflexibleinbe