武科大機械專業(yè)英語Lesson39

Lesson39GearManufacturingMethodsTerminologyTexttour

1/12/20241《機械工程專業(yè)英語教程》Terminology1/12/20242《機械工程專業(yè)英語教程》AnnularShapedlikeorformingaring.環(huán)形的，輪狀的：形狀像環(huán)或形成環(huán)狀。Annulargear

內齒輪,齒圈（也稱為internalgear）《機械工程專業(yè)英語教程》1/12/2024Helicalgear

斜齒輪

3Hob

滾刀1/12/2024《機械工程專業(yè)英語教程》4Worm

蝸桿Wormgear

1.Agearconsistingofaspirallythreadedshaftandawheelwithmarginalteeththatmeshintoit蝸輪蝸桿副2.Thetoothedwheelofthisgear,awormwheel蝸輪1/12/2024《機械工程專業(yè)英語教程》5Broach

拉刀Swarf

Finemetallicfilingsorshavingsremovedbyacuttingtool.小鐵屑：用銼或剃等加工方法去除的細小金屬屑。1/12/2024《機械工程專業(yè)英語教程》6DressingDressingistheprocessofconditioningworngrainsonthesurfaceofagrindingwheelbyproducingsharpnewedgesongrainssothattheycancutmoreefficiently.砂輪修整：使砂輪表面磨鈍的磨粒上產(chǎn)生新的鋒利的切削刃，使其能夠更有效地進行切削工作。1/12/2024《機械工程專業(yè)英語教程》7GearPlaning（刨齒）Theshapeofthespacebetweengearteethiscomplexandvarieswiththenumberofteethonthegearaswellastoothmodule（模數(shù)），somostgearmanufacturingmethodsgeneratethetoothflank(齒腹)insteadofforming（采用展成法加工齒面而不是采用成形法加工）.《機械工程專業(yè)英語教程》1/12/2024Texttour8Gearplaningusesa

reciprocatingrack（往復運動的齒條刀）,

stroking（擊、打、切）inthedirectionofthehelix（螺旋）onagearwithagradualgenerationofformastherackeffectivelyrollsroundthe

gearblank(齒輪毛坯)（當齒條刀繞齒輪坯料滾切并沿其螺旋線方向運動時，齒形就會被逐漸展成）.…………Therack

isrelievedoutofcontact（脫離接觸）forthereturnstroke

asinnormalshapingorplaning（與普通的刨削加工相同）.Ithasthegreatadvantagethatthecuttingtoolisasimplerackwith(nearly)straightsidedteethwhichcaneasilybegroundaccurately(刀具為具有直線齒形或者接近與直線齒形的齒條，其齒面易于進行精確磨削加工).…………Thismethodis

littleused(幾乎不用)forhighproductionbecauseitisrelativelyslowinoperation

duetothehightoolandslidemass(由于刀具和滑枕的質量較大)；for

jobbing（重復性很小的工作）purposesthe

slowstrokingratedoesnotmatterandlowtoolcostsgiveanadvantagewhere

unusualsizesorprofilemodificationsarerequired.（對于單件或者少量的齒輪加工而言，緩慢的行程速度帶來的影響不大，而且較低的刀具成本對于那些特殊規(guī)格和需要進行齒廓修形的齒輪來說則是一個有利的條件）GearShaping（插齒）Gearshapingisinherentlysimilarto

gearplaning（刨齒加工）butusesa

circularcutter（圓形刀具）insteadofarack(齒條刀)andtheresultingreductioninthe

reciprocatinginertia（運動慣性）allowsmuchhigher

strokingspeeds（行程速度）；moderngear

shapers（插齒機）cuttingcargearscanrunat2000cuttingstrokesperminute.Theshapeofthecutterisroughlythesameasan

involutegear（漸開線齒輪）butthetipsoftheteetharerounded.Thegeneratingdrivebetweencutterandworkpiecedoesnotinvolvearackorleadscrewsinceonlycircularmotionisinvolved（由于刀具與工件之間的展成運動只包含圓周運動，因此不需要齒條或者絲杠）.Thetoolandworkpiece

movetangentially(切向移動)typically0.5mmforeachstrokeofthecutter.Onthereturnstrokethecuttermustberetracted（退讓）about1mmtogiveclearanceotherwisetoolruboccursonthebackstroke（退刀）andfailureisrapid.Theadvantagesofgearshapingarethatproductionratesarerelativelyhighandthatitispossibleto

cutrightuptoashoulder（將齒插到接近軸肩處）.Unfortunately,for

helicalgears（斜齒輪）,a

helicalguide（螺旋導軌）isrequiredtoimposearotationalmotiononthe

strokingmotion（需要有一個能夠產(chǎn)生繞插齒運動行程本身旋轉的螺旋導軌）；…………suchhelicalguidescannotbeproducedeasilyorcheaplysothemethodisonlysuitable

forlongrunswithhelicalgears（斜齒輪的大批量加工）sincespecialcuttersandguidesmustbemanufacturedforeachdifferenthelixangle.Agreatadvantageofgearshapingisitsabilitytocut

annular（環(huán)形的，輪狀的）gearssuchasthoserequiredforlarge

epicyclicdrives（行星齒輪傳動）.GearHobbing（滾齒）Gearhobbing，themostusedmetalcuttingmethod，usestherackgeneratingprinciple（齒條展成原理）butavoidsslowreciprocationbymountingmany“racks”ona

rotatingcutter（旋轉刀具）.The“racks”aredisplacedaxiallytoforma

gashed（很深的裂縫）worm（這些“齒條”軸向排布，形成了有縫的蝸桿）.Metalremovalratesarehighsincenoreciprocationofhoborworkpiece（滾刀和工件）isrequiredandsocuttingspeedsof40m/mincanbeusedforconventionalhobs（普通滾刀）andupto150m/minforcarbidehobs（硬質合金滾刀）.Typicallywitha100mmdiameterhobtherotationspeedwillbe100rpmandsoatwentytoothworkpiecewillrotateat5rpm.…………Eachrevolutionoftheworkpiecewillcorrespondto0.75mmfeedsothehobwilladvancethroughtheworkpieceatabout4mmperminute.Forcarproduction

roughingmultiplestarthobs（多頭粗加工滾刀）canbeusedwithcoarsefeedsof3mmperrevolutionsothat100rpmonthecutter,a

two-starthob（雙頭滾刀）anda20toothgearwillgiveafeedrateof30mm/min.GearBroaching（拉齒）Gearbroachingisnotusuallyusedfor

helicalgears（斜齒輪）butisusefulforinternal

spurgears（直齒輪）；theprincipleuseofbroaching

inthiscontext（在這種情況下）isfor

internalsplines（內花鍵）whichcannoteasilybemadebyanyothermethod.Aswithallbroachingthemethodisonlyeconomicforlargequantitiessince

setupcosts（設備的費用）arehigh.GearBroachinggiveshighaccuracyandlowsurfaceroughness（低表面粗糙度）butlikeallcuttingprocessesislimitedto“soft”materialswhichmustbesubsequently（隨后）case-hardenedorheattreated（表面硬化或者熱處理），givingdistortion（產(chǎn)生變形）.GearShaving（剃齒）Gearshavingisusedasfinishingprocessesforgearsinthe“soft”state.Theobjectiveisto

improvesurfaceroughnessandprofile（降低齒面粗糙度和改善齒廓形狀）bymatingtheroughed-outgearwitha“cutter”whichwillimproveform（通過采用具有較高齒形精度的“刀具”與經(jīng)過粗加工的齒輪進行嚙合）.Agearshavingcutterlookslikeagearwhichhasextraclearance（附加的凹槽）attheroot(forswarfandcoolantremoval細鐵屑冷卻液排除)andwhosetoothflankshavebeengrooved（開小槽）togivecuttingedges（形成切削刃）.…………Itisruninmeshwiththeroughgearwithcrossedaxes（剃齒刀與經(jīng)過粗加工的齒輪成交錯軸嚙合傳動）sothatthereisintheorypointcontact（點接觸）witharelativevelocity

alongtheteeth（沿輪齒）giving

scrapingaction（刮削作用）.Thegearshavingcutterteetharerelativelyflexibleinbendingandsowillonlyoperateeffectivelywhentheyareindoublecontactbetweentwogearteeth（剃齒刀的刀齒具有相當?shù)膹澢嵝?，因此，只有當它們在兩個輪齒之間并且與這兩個輪齒都接觸時，才能有效地進行切削工作）.…………Thegearandcutteroperateathighrotationalspeedswith

traversing（通過、穿過）oftheworkfaceandabout100micronofmaterialisremoved.

Cycletimes（周期時間）canbelessthanhalfaminuteandthemachinesarenotexpensivebutcutterare

delicate（精密）anddifficulttomanufacture.GearGrinding（磨齒）Geargrindingisextremelyimportantbecauseitisthemainway

hardenedgears（淬硬齒輪）aremachined.Whenhighaccuracyisrequireditisnotsufficientto

pre-correct（預先校正）forheattreatmentdistortionandgrindingisthennecessary.Thesimplestapproachtogeargrindingisformgrinding（成形磨削法）.Thewheelprofileisdressed（修整）accuratelytoshapeusingsinglepointdiamondswhicharecontrolledbytemplatescuttotheexactshaperequired（采用由精密切削成形的樣板控制的單刃金剛石可以將砂輪修整成精確的形狀）.…………Theprofiledwheelisthen

reciprocated（往返進給）

axiallyalongthegear（沿軸向）,whenonetoothshapehasbeenfinished,involvingtypically100micronmetalremoval,thegearis

indexedto（索引、分度到）thenexttoothspace.Thismethodisfairlyslowbutgiveshighaccuracyconsistently.Settingupislengthybecausedifferent

dressingtemplates（砂輪修整樣板）areneededifmodule,numberofteeth,helixangle,or

profilecorrection（齒廓修形量）arechanged.Thefastestgeargrindingmethodusesthesameprincipleasgearhobbing（滾齒）butreplacesa

gashedandrelievedworm（有排屑槽的蝸桿形滾齒刀）byagrindingwheelwhichisarackinsection（截面為齒條的砂輪）.