車輛變速器螺旋行星齒輪推力錐技術(shù)的開(kāi)發(fā)

0不同驅(qū)動(dòng)和限制運(yùn)行系統(tǒng)在數(shù)學(xué)領(lǐng)域，有很多方法和熱點(diǎn)。人們關(guān)注部件和系統(tǒng)的開(kāi)發(fā),以及開(kāi)發(fā)、生產(chǎn)方式和技術(shù)的進(jìn)步。性能提高和重量減輕依然是研發(fā)的主要目標(biāo),尤其在車輛變速器的設(shè)計(jì)中。在2001年,ZF成功將第一個(gè)六速自動(dòng)變速器投入市場(chǎng)。這些變速器現(xiàn)在滿足了各種引擎轉(zhuǎn)矩需求,從普通驅(qū)動(dòng),裝備分動(dòng)器的全輪驅(qū)動(dòng)到集成全驅(qū)的前置縱向驅(qū)動(dòng),最高可達(dá)750Nm。新型變矩器,更高的行星齒輪數(shù),優(yōu)化的軸系、齒圈和行星齒輪架:多樣化的改進(jìn)帶來(lái)了轉(zhuǎn)矩能力和動(dòng)力——重量比的提升,見(jiàn)圖1。減少油耗是當(dāng)前的主要話題之一。多種不同的驅(qū)動(dòng)和變速系統(tǒng)正在開(kāi)發(fā)中且相互競(jìng)爭(zhēng)。通過(guò)不斷地研究及增加自動(dòng)變速器的檔位,過(guò)去幾年來(lái),油耗顯著下降,見(jiàn)圖2。下面從眾多齒輪和變速器的設(shè)計(jì)開(kāi)發(fā)活動(dòng)中,通過(guò)一些例子詳述幾個(gè)話題。1降低換行噪聲1.1當(dāng)前和經(jīng)驗(yàn)車輛變速器設(shè)計(jì)的現(xiàn)狀有以下幾個(gè)特點(diǎn):0-st-pcr和—INTRODUCTIONTrendsanddevelopmentmethodsintheareaoftransmissionsarerathervariedtoday.Theyconcernthedevelopmentofcomponentsandsystems,andtheimprovementofmethodsandtechnologiesindevelopmentandproduction.Thetrendtowardsperformanceincreaseandweightreductioncontinues,inparticularinvehicletransmissiondesign.In2001ZFsuccessfullyintroducedthefirst6-speed-automatic-transmissiononthemarket.Thesetransmissionsnowcovertheenginetorquerequirementsforstandarddrives,allwheeldrivesequippedwithtransfercasesandfront-longitudinaldriveswithintegratedall-wheeldrivesupto750Nm.Alotofdifferentimprovementsleadtoanencreasedtorquecapacityandpower-to-weightratio:newtorqueconverter,highernumberofplanets,optimizedshafts,ringgearsandplanetcarriers,Fig.1.Reductionoffuelconsumptionisoneofthemaintopicstoday.Differentdrivelineandtransmissionsystemsareunderdevelopmentandcompeteeachother.Bycontinousdevelopmentsandencreasingthenumberofspeedsofautomatictransmissionsasignificantreductionoffuelconsumptioncouldbereachedduringthelastyears,Fig.2.*特定的負(fù)載,變化的負(fù)載范圍*噪聲標(biāo)準(zhǔn)嚴(yán)格,尤其在部分載荷范圍內(nèi)*受車輛影響大*輕量化結(jié)構(gòu),緊湊設(shè)計(jì)*要求經(jīng)濟(jì)的生產(chǎn)方法,以限制成本同時(shí)保證高質(zhì)量。車輛變速器的主要噪聲源在于齒輪,見(jiàn)圖3。Fromthelargenumberofactivitiesanddevelopmentsingearandtransmissiondesignthefollowingtopicsshallbeelaboratedbyusingafewexamples.1內(nèi)省1.1“企業(yè)”非“企業(yè)”,即同一transmissonso,訴訟Thesituationinvehicletransmissiondesignischaracterizedbythefollowingproblems:*Highspecificloads,variingloadspectrums*Demandingnoisespecifications,inparticularinpartialloadranges,strongvehicleinfluence*Light-weightconstruction,compactdesign*Searchforeconomicproductionmethodstolimitcostsrelatedtohighqualitydemands.Themainsourceofnoiseinvehicletransmissionsisgenerallythegearing;seeFig.3.Onlyinexceptionalcasesisnoisecausedbythebearings,clutches,orlooseelements,suchassynchronizers.Thegearnoisesaretransmittedviawheels,shafts,andbearingstothetransmissioncase.Whenemittedbythetransmissioncase,itisperceivedasairbornenoise.Furthermore,structure-bornenoisecanexcitethevehiclebodydirectlythroughthetransmissioncasemounting.Regardingthenoisetypes,onedistinguishesbetweengearrattleinidle,accelerationrattle,andgearwhine;seeTab1.Whilerattleinidleandduringaccelerationiscausedbytheunloadedgearsandisusuallyduetotheunevennessofdriveengines,gearwhineoccursinthegearsetsthatareunderload.Thefollowingoptionsforgearoptimizationconcerngearwhinenoise.Toobtaininformationaboutquietgears,extensivetestshavebeenperformedwithdifferentshapesofteeth.Theresultsofthesetests,whichwererunonaclosedpowergeartestrigareshowninFig.4.Asonecansee,highcontactratiogearsachieveanoisereductionofapproximately5dBcomparedwithnormalspurgearing.Themostsignificantimprovementcanbeachievedwithhelicalgears.Dependingonthetransversecontactratio,improvementsof10—15dBcomparedwithspurgearsarefeasible.Therefore,itisunderstandablethathelicalgearsarepreferredinvehicleapplications.Wherenoiserequirementsareverydemanding,gearswithhighertransversecontactratiosareused.Inadditiontothetoothgeometry,thetoothqualityalsoaffectsthenoisepropertiesofthegears,especiallyunderpartialload.Today,eventhesurfaceorgrindingstructureoftheteethplayarole.只有在特殊情況下,軸承、離合器或松散元件(如同步器)會(huì)成為噪聲源。齒輪噪聲通過(guò)飛輪、曲軸和軸承傳遞至變速殼體。由殼體發(fā)散的噪聲表現(xiàn)為空傳噪聲。此外,由結(jié)構(gòu)傳遞的噪聲會(huì)通過(guò)變速器殼體總成直接作用于車體?？紤]噪聲的類型,可區(qū)分為齒輪怠速噪聲,加速噪聲和齒輪高頻噪聲,見(jiàn)表1。怠速和加速時(shí)的噪聲是由非負(fù)載的齒輪產(chǎn)生的,通常是因?yàn)橐骝?qū)動(dòng)力的不均衡造成,而齒輪高頻噪聲由負(fù)載齒輪組產(chǎn)生。下列屬性與優(yōu)化齒輪高頻噪聲有關(guān)。為取得安靜齒輪的信息,要對(duì)不同的齒形進(jìn)行大量的測(cè)試。這些測(cè)試在一個(gè)動(dòng)力封閉的齒輪測(cè)試臺(tái)上進(jìn)行,結(jié)果見(jiàn)圖4。由圖可見(jiàn),與普通直齒輪相比,大重合度齒輪能降低約5dB的噪聲。螺旋齒輪的降噪性能最顯著,根據(jù)不同的端面重合度,與直齒輪相比可多降低10-15dB的噪聲。因此,在車輛應(yīng)用中螺旋齒輪更受歡迎。當(dāng)降噪要求很高時(shí),需要更大重合度的齒輪。除了齒形的幾何設(shè)計(jì),齒的質(zhì)量也影響齒輪的噪聲性能,尤其在部分負(fù)荷情況下?，F(xiàn)在,齒的表面或磨削構(gòu)造也起一定的作用。Fig.5showsthenoisemeasurementresultswithagearsetthatwasmachinedusingdifferentmethods,thushavingdifferentdegreesofwaviness.Ifgearwavinessistoohighandthelubricantfilmthicknesslow,so-calledghostfrequenciesarenoticeable,whicharenotmultiplesofthetoothfrequency.Therefore,finishingprocessesarerequiredforgearswithdemandingnoisespecifications.Wherenoiseandqualityrequirementsarehigh,thetoothprofileshouldbelookedattopologically,i.e.three-dimensionally.Manufacturingdistortions-thatis,deviationsfromtheidealtoothgeometry-canoccurinthemarginareasofthetoothprofile,seeFig.6.Thesedependonthegrindingmethod,thehelicalangle,andthecrowningofthegear.Asgreaterthehelixangleandthecrowningare,asgreaterarethedeviations.Wehavedevelopedcomputerprogramstosimulatethedifferentgeargrindingprocessesandtodeterminetheamountoftopologicaldistortions.Fig.7showsanexampleofanoise-optimizedgearsetina5-speedautomatictransmissionforapassengercar.Itisthe3-geartransfergearsetintheall-wheeldrivetransmission.Witharemarkabletoothwidthof50mm,thegearsethasatotalcontactratiooftransmissonetraceforadwhich-en發(fā)連接反應(yīng)圖5顯示了對(duì)用不同加工方法制作的齒輪進(jìn)行的噪聲測(cè)量,這些齒輪的波紋度不同。如果齒輪波紋度過(guò)大,潤(rùn)滑油膜過(guò)薄,就能觀察到所謂的幽靈頻率,這些頻率不是齒頻的倍數(shù)。當(dāng)噪聲和質(zhì)量要求較高時(shí),應(yīng)從拓?fù)?即三維的角度研究齒的輪廓。在齒形輪廓的邊界區(qū)域存在制造誤差——與理想齒形的偏差,見(jiàn)圖6。誤差取決于磨削工藝,螺旋角和凸面。螺旋角和凸面越大,偏差越大。我們開(kāi)發(fā)了一種程序來(lái)仿真不同的齒輪磨削過(guò)程以確定拓?fù)湔`差量。圖7是一種噪聲優(yōu)化齒輪組,用于乘用車5速自動(dòng)變速器。該齒輪組位于全輪驅(qū)動(dòng)變速器中的3齒輪分動(dòng)器,其齒寬達(dá)50mm,齒輪總嚙合度為4.1。Thecalculationofstressesandvibrationexci-tationongearsneedsthedetailedconsiderationofdeviationsanddeflectionsinthemesh.Theloaddistributionalongthecontactlinesisthebasisfortheanalysisofcontactandbendingstressdistributions.Deformationinfluencecoefficientsareusedusuallyforthecalculationoftheloaddistribution,whichenableaverydetailedmodelingofthetoothelasticity.Thesimplemodelwithseparatedthinslicescanbeusedalsoforaroughapproximation.AspecialmethodisusedintheprogramLVR/3/,whichisbasedonthethinslicedtoothmodelwithadditionalcouplingstiffnessbetweentheslices.Thecouplingenablesbothaveryaccuratemodelingofthedeformationtracealongthefacewidthandanextremefastcalculationduetothetridiagonalcoefficientmatrix,whichisobtainedfromthestiffnessmodel.Thecouplingstiffnessmethodhasadvantagesagainsttheothermethods,itdeliversmoreaccurateresultscomparedtotheseparatedslicemodelanditismuchfasterthantheinfluencecoefficientmethod.Thetransmissionerrorisconsideredasthemainsourceofnoiseexcitedbythegearmesh.Therearemanypublicationsabouttransmissionerroranalysisavailable.Thefollowingexamplesshowtheabilityforpredictingthenoiseexcitationbasedontransmissionerrorcalculations.Severalmodificationsofspurandhelicalgearsweretestedinabasicprojecttoanalyzetheirpotentialfornoisereduction.Tipreliefandgeneratedendreliefwithdifferentamountandlengthwereusedintheinvestigation.1.2聲激勵(lì)的困難計(jì)算齒輪上的應(yīng)力和振動(dòng)沖擊需要詳細(xì)考慮嚙合的偏差和變形。接觸線上的載荷分布是分析接觸應(yīng)力和彎曲應(yīng)力分布的基礎(chǔ)。通常使用變形影響系數(shù)來(lái)計(jì)算載荷分布,這樣就能建立詳細(xì)的齒彈性模型。對(duì)于粗糙的估計(jì),也可使用分離的薄片模型。LVR算法是一種特殊的方法,這種算法是基于薄片模型的,考慮了片間耦合剛度。由于考慮了耦合,對(duì)沿表面寬度形變軌跡的建模變得非常準(zhǔn)確,同時(shí)由于從剛度模型得到了三對(duì)角矩陣,計(jì)算也特別快。與其他模型相比,耦合剛度模型的準(zhǔn)確度高于分離薄片模型,計(jì)算速度遠(yuǎn)快于影響系數(shù)法。傳遞誤差是齒輪嚙合噪聲的主要來(lái)源。有很多文章分析了傳遞誤差。下面是一個(gè)基于傳遞誤差計(jì)算預(yù)測(cè)噪聲激勵(lì)的例子。這個(gè)項(xiàng)目中測(cè)試了幾種直齒輪和螺旋齒輪來(lái)分析它們的降噪潛力。在分析中采用了不同數(shù)目和長(zhǎng)度的修緣和齒端修薄。圖8是對(duì)修緣長(zhǎng)度不同的直齒輪V1測(cè)得的傳遞誤差。表2中列出了齒輪數(shù)據(jù)。計(jì)算得到的傳遞誤差與測(cè)量軌跡較好吻合。用LVR可較好估計(jì)傳遞誤差曲線隨載荷的改變。所示的傳輸誤差軌跡是基于與實(shí)際漸開(kāi)線的測(cè)量偏差而計(jì)算的。如果只使用目標(biāo)輪廓,并且不考慮輪廓的制造誤差,計(jì)算軌跡與測(cè)量軌跡的偏差會(huì)更大。由于實(shí)際輪廓與目標(biāo)間存在制造誤差,即使制造輪廓在公差限內(nèi),精確估計(jì)噪聲激勵(lì)也比較困難。與直齒輪相比,螺旋齒輪的噪聲估計(jì)要困難的多,因?yàn)閭鬟f誤差的變化與直齒輪中的相比不到十分之一。比較圖9和圖8能清楚的看到這一點(diǎn)(傳遞誤差軸的坐標(biāo)不同!)ThemeasuredtransmissionerrortracesareshowninFig.8forspurgearsV1withlongandshorttiprelief.ThegeardataarelistedinTab.2.Thecalculatedtransmissionerrormatchesthemeasuredtraceswell.TheloaddependentchangeofthetransmissionerrorcurvecouldbedeterminedwithLVRingoodapproximation.Theshowntransmissionerrortraceswerecalculatedbasedonmeasureddeviationsfromthetrueinvolute.Thedeviationbetweenthecalculatedandthemeasuredtransmissionerrortracewouldbelarger,ifonlythetargetprofileisusedandthedeviationsofthemanufacturedprofilearenotconsidered.Thedeviationoftherealmanufacturedprofilefromthetargetmakesitdifficulttopredictthenoiseexcitationveryaccurate,evenifthemanufacturedprofilelieswithintolerancelimits.Thenoisepredictionforhelicalgearsismuchmoredifficultthanforspurgears,becausetheamountoftransmissionerrorvariationislessthanatenthofthevariationonspurgears.AcomparisonofFig.9withFig.8showsthisclearly(thetransmissionerroraxisisdifferentlyscaled!).Themacrogeometryofthehelicaltestgearswasdesignedforlownoiseexcitationwithanaxialoverlapratioequalto1.Thetransmissionerrorvariationisverylowontheunmodifiedgear.Ashorttipreliefforstressreductionclosetothetipedgedoesnotchangemuchthetransmissionerrortrace.TheexcitationlevelofhelicalgearsetV3isplottedinFig.10fordifferentamountsoftiprelief.所測(cè)螺旋齒輪的宏觀尺寸是按低噪聲激勵(lì)設(shè)計(jì)的,軸向重疊率為1.在未修改的齒輪中,傳遞誤差變化非常小。為減小應(yīng)力,在齒尖邊沿作了短修緣,這對(duì)傳遞誤差軌跡沒(méi)有大的影響。圖10中繪制了螺旋齒輪組V3的在不同數(shù)量修緣下的激勵(lì)等級(jí)。顯然,激勵(lì)水平小于被測(cè)的直齒輪。在低載荷下,齒形偏差對(duì)傳遞誤差的影響更大,故計(jì)算與測(cè)量值的偏差較大。在大載荷下齒形變形起決定作用,因此能非常準(zhǔn)確的估計(jì)被測(cè)軌跡?；跍?zhǔn)靜態(tài)齒作用力的激勵(lì)水平LA在LVR中是由以下公式直接計(jì)算的:LA=20log(∑i=1n(i?AiKmN/μm)2??????????????√)LA=20log(∑i=1n(i?AiΚmΝ/μm)2)Thelevelisclearlysmallerthanthatofthetestedspurgears.Thedeviationbetweencalculatedandmeasuredvaluesislargeratlowloads,wherethetransmissionerrorismoreinfluencedbytoothdeviations.Averygoodapproximationtothemeasuredtracesisachievedathighloads,wherethetoothdeflectionismoredominant.TheexcitationlevelLA,whichisbasedonquasi-statictoothforce/3/,iscalculatedalsodirectlyinLVRwithfollowingformula:LA=20log(∑i=1n(i?AiKmN/μm)2??????????????√)LA=20log(∑i=1n(i?AiΚmΝ/μm)2)*LA——excitationlevelbasedonquasi-staticforce*Km——meanmeshstiffness[N/μm]*n—numberofconsideredtransmissionerrorharmonics*Ai—Amplitudeoftransmissionerrorharmonic#iTheprogramLVRisalsoaveryusefultoolforanalyzingstressdistributionsandtransmissionerrorvariationsfortopologicallymodifiedgears.Thosemodificationsareusedtoimprovethebehaviorofthegearsbeyondthelevel,whichisreachedwithtraditionalmodifications.Thereisstillaproblemwithloaddependentdeflections,whichhaveaninfluenceontheeffectivedeviationfromtrueinvoluteinmesh.Consideringthoseinfluencesthetopologycanbeanoptimumonlyinaloadrange,whichissometimesverynarrow.Themaingoalinnoisereductionisdefining“robust”topologies,whichhaveanearlyoptimuminfluenceonthetransmissionerrorinawideloadrange.Thefollowingexampleshowssomeresultsforaspecialtipmodification,whichisusedforspurgears.Spurgearsarenotthequiettypeofgears,butinsomecasestheyaremoreusefulthanhelicalgears,especiallyifaxialloadsareaproblem.Onebigdisadvantageofspurgearsisthehightransmissionerrorvariation.Thisexcitationcanbereducedwithstandardtipreliefonlyinanarrowloadrange.Themodifiedgearsshowalargeexcitationlevelatlowloads,whichisevenhigherthanthatofunmodifiedgears.Atipmodificationisnecessary,whichproducesaloaddependenteffectiveamountofrelief.Thiscanbeachievedbymakingtheeffectivestiffnessclearlyloaddependentwithleadcrowning.Aspecialtypeofcrowninginthetipregionwasdevelopedandusedinourtests.ThesameideaisusedforinstanceinAxicon’s“DifferentialCrowning”/4/.TheshapeofthespecialtipmodificationwasdeterminedinaseriesofLVRcalculations.AnyarrayofdeviationsfromtheinvolutecanbeusedasinputtopologyinLVR.Thegridofcontactpoints,atwhichthetopologyisdefined,doesnothavetobeequidistant.Thedistancebetweenthegridpointcanbeverysmallinthetipandedgeregionsandlargerintheunmodifiedarea.*LA——基于準(zhǔn)靜態(tài)力的激勵(lì)水平*Km——平均嚙合剛度[N/μm]*n—考慮的傳遞誤差諧波數(shù)目*Ai—傳遞誤差諧波的放大系數(shù)#iLVR算法也適用于對(duì)拓?fù)湫拚^(guò)的齒輪進(jìn)行載荷分布分析和傳遞誤差變化分析。修正齒輪是為了提高其性能。由載荷引起的變形會(huì)對(duì)嚙合實(shí)際漸開(kāi)線的偏差有影響,在此仍然有個(gè)問(wèn)題?？紤]到這些影響,一種拓?fù)浣Y(jié)構(gòu)只在某個(gè)載荷范圍內(nèi)是最優(yōu)的,這個(gè)范圍有時(shí)很窄。噪聲降低的主要目標(biāo)是找到“健壯”的拓?fù)浣Y(jié)構(gòu),其在較大的載荷范圍內(nèi)對(duì)傳遞誤差的影響應(yīng)接近最優(yōu)。下面的例子展示了一種直齒輪特殊頂端修正的實(shí)驗(yàn)結(jié)果。直齒輪不是安靜齒輪,但在某些情況下比螺旋齒輪更有用,尤其在軸載荷有問(wèn)題的情況下。直齒輪的一大缺點(diǎn)是傳遞誤差變化較大。用標(biāo)準(zhǔn)修緣只能在較窄的載荷范圍內(nèi)減小激勵(lì)。修正過(guò)的齒輪在低載荷下激勵(lì)較大,甚至大于未修正的齒輪。尖端修正是必要的,它能產(chǎn)生一組取決于載荷的有效修正?？梢杂们褒X冠來(lái)使有效剛度明顯取決于載荷。我們?cè)跍y(cè)試中開(kāi)發(fā)并使用了一種特殊類型的頂端齒冠。Axion在“DifferentialCrowning”一文中使用了同樣的思路。通過(guò)一系列LVR的計(jì)算可決定特殊頂端修正的外形。與漸開(kāi)線的偏差數(shù)組作為L(zhǎng)VR的輸入拓?fù)?。定義拓?fù)涞慕佑|網(wǎng)格不一定是等間距的。在齒尖和邊界區(qū),網(wǎng)格點(diǎn)可以很窄,在非修正區(qū)則可以較大。在測(cè)試中,針對(duì)特殊頂端修正(見(jiàn)圖11)、未修正和標(biāo)準(zhǔn)長(zhǎng)修緣的齒輪,分別測(cè)量了傳遞誤差和噪聲水平。所測(cè)得的噪聲水平見(jiàn)圖12。經(jīng)特殊修正的齒輪組表現(xiàn)出了預(yù)期的優(yōu)點(diǎn),在寬載荷范圍內(nèi)噪聲水平較低。使用標(biāo)準(zhǔn)工具不可能對(duì)拓?fù)湫拚M(jìn)行設(shè)計(jì)和理論分析。LVA非常有效地做到了這一點(diǎn)。只有齒輪制造質(zhì)量高,被測(cè)拓?fù)浣Y(jié)構(gòu)才能表現(xiàn)出降噪作用。如果不可能使用螺旋齒輪或高嚙合比直齒輪,可用特制頂冠來(lái)降噪。Thetransmissionerrorandnoiselevelweredeterminedintestrunsforspurgearswiththespecialtipmodification(seeFig.11),unmodifiedgears,andgearswithstandardlongtiprelief.ThemeasuredexcitationlevelisplottedinFig.12.Thespeciallymodifiedgearsetshowsthepredictedadvantageoflowexcitationinawideloadrange.Thedesignandtheoreticalanalysisofthetopologicalmodificationwasnotpossiblewithstandardtools.TheprogramLVRenabledthatinaveryeffectiveway.Thetestedtopologyleadstotheshownnoisereductiononlyifthegearsarefinishedinhighquality.Thespecialtipgivesachancefornoisereductioniftheuseofhelicalgearsorhighcontactratiospurgearsisimpossible.2車輛過(guò)塔器中的螺旋齒輪12至16速的商用車變速器通常帶有次級(jí)行星輪組,見(jiàn)圖13。過(guò)去,這些行星齒輪都是直齒輪。在乘用車變速器中,所有行星齒輪都是螺旋齒輪。由于卡車變速器對(duì)降噪的需求也在不斷提高,我門將螺旋齒輪應(yīng)用于行星齒輪組,以顯著提高降噪性能。其中一項(xiàng)要求是不改變安裝空間,還需要承受軸向力和螺旋齒輪傾斜扭矩。在進(jìn)行相關(guān)研究后,我們決定用所謂推力錐來(lái)承受螺旋齒輪傾斜和軸向力。然而,由于經(jīng)驗(yàn)有限,缺乏車輛變速器上的應(yīng)用,必須從最底層的開(kāi)發(fā)做起。這些軸承在固定變速器設(shè)計(jì)中很常見(jiàn),尤其是渦輪變速器。早在1922年,BBC報(bào)道了此種專利,見(jiàn)圖14。2requelt均有互聯(lián)網(wǎng)最短路徑—HELICALPLANETARYGEARSWITHTHRUSTCONETECHNOLOGYCommercialvehicletransmissionswith12to16speedsusuallyhaveasecondaryplanetarygearset;seeFig.13.Inthepast,theseplanetarygearsetsweredesignedasspurgearsin.Inpassengercarautomatictransmissions,allplanetarygearshavehelicalgearing.Becauseoftheincreasingdemandsonnoisereductionalsofortrucktransmissionswehavedevelopedplanetarygearsetswithhelicalgearing,whicharetoachieveaconsiderableimprovementofnoiseproperties.Onerequirementwastokeeptheinstallationspacethesame.Theaxialforcesandmomentsoftiltofthehelicalgearsrequiredsupport.Aftertherelevantstudies,wedecidedtosupportthetiltandaxialforcesinhelicalgearingswithso-calledthrustcones.However,duetothelimitedexperienceandlackofapplicationsinvehicletransmissiondesign,baselinedevelopmentshadtobestarted/5/.Thesetypesofaxialbearingsareknownfromstationarytransmissiondesign;inparticular,turbotransmissions.Asearlyas1922,BBCproposedsuchapatent;seeFig.14.Here,theaxialforcefromhelicalgearingsissupportedbytaperedthrustcones.Thesecanbedesignedforone-sidedortwo-sidedfunction.Thus,onlyoneshaftneedsaxialsupport;theshaftofthematinggearissupportedbythethrustcones.Itisaclosedflowofforcesbetweenhelicalgearingandthrustcollars.ThefunctionprincipleisshowninFig.15.Theconicalshapecreatesalubricatinggapbetweenthetapereddiscs,therebycreatingahydrodynamiclubricatinglayer.Dependingonthegearratioanddiameterofthethrustcones,differentslidingspeedsresultatthethrustcollars.TheHertzianstressdependsinparticularonthetaperangle.Usually,ithasaratherlowvalueof1～3°.Inaplanetarytransmission,thrustconesshouldbeplacedbetweentheplanetsandthesun,aswellastheplanetsandtheringgear;seeFig.16.Here,theconicalsurfacesmakedirectcontactwiththefacesoftheplanetgears,therebyrealizingaparticularlycompactdesign.這里,螺旋齒輪的軸向力由漸縮的推力錐承受?？梢栽O(shè)計(jì)成單向功能的,也可以是雙向的。這樣,只有一個(gè)軸需要承受軸向力,配對(duì)齒輪的軸是由推力錐支承的。在螺旋齒輪和推力環(huán)之間力是閉環(huán)流動(dòng)的。功能原理見(jiàn)圖15。錐形體在配對(duì)盤體之間形成潤(rùn)滑槽,即形成了液力潤(rùn)滑層。推力環(huán)之間滑動(dòng)速度的不同取決于齒數(shù)比和推力錐的直徑。赫氏應(yīng)力由錐角決定,此角度通常為1～3度左右的小量。在行星變速器中,推力錐須置于行星輪和太陽(yáng)輪之間,以及行星輪與行星架之間,見(jiàn)圖16.這里,錐面直接與行星輪面接觸,因此實(shí)現(xiàn)了緊湊化設(shè)計(jì)。Asmentionedpreviously,thisthrustconetechniquehasnotbeendevelopedandisnotstateoftheartforvehicleplanetarytransmissions.Therefore,aresearchprogramwasstartedtoobtaintherespectiveknowledgeforareliablelayout.Forthispurpose,differentgeometrieswereexamined.Thepermissiblestressvaluesweredeterminedasafunctionofmaterial,lubricant,andslip;andthensuitablelayouttheoriesweredeveloped.Therespectivetestswereperformedonamodifiedgeartestrig;seeFig.17.Thetestrigwasequippedwithonespurgearsetandonesetwithhelicalgearing.Oneshafthadnoaxialsupport;rather,theaxialforcewassupportedbythrustcollars.Therebyitwaspossibletoapplyaxialloadstothethrustcollarsasafunctionoftorque.Withanauxiliarydevice,itwaspossibletoapplyadditionalaxialforces,therebyapplyingdifferentloadstothethrustcollars.Itshouldbenotedthatthrustcollarsaresubjecttothesamedamagecriteriaasgears,namelyseizing,fatigue,wear,etc.Aftersuccessfulbaselinedevelopment,thethrustconesweredesignedforcommercialvehiclesandtested.Theyhavebeenseriesequipmentformorethan10years.Bychangingtheplanetarygearsetfromspurtohelicalgearing,ithasbeenpossibletosignificantlyreducethenoisedevelopmentina16-gearcommercialvehicle,seeFig.18.3推力環(huán)的測(cè)試和參數(shù)Intransmissionswithshaftsthatarenotarrangedparalleltotheaxis,torquetransmissionispossiblebymeansofvariousdesignssuchasbevelorcrowngears,universalshafts,orconicalinvolutegears(beveloids).Theuseofconicalinvolutegearsisparticularlyidealforsmallshaftangles(lessthan15°),astheyofferbenefitswithregardtoeaseofproduction,designfeatures,andoverallinput.Conicalinvolutegearscanbeusedintrans-missionswithintersectingorskewaxesorintrans-missionswithparallelaxesforbacklash-freeoperation.Duetothefactthatselectionoftheconeangledoesnotdependonthecrossedaxesangle,pairingisalsopossiblewithcylindricalgears.Asbeveloidscanbeproducedasexternalandinternalgears,awholematrixofpairingoptionsresultsandthedesignerisprovidedwithahighdegreeofflexibility.如前所述,推力錐技術(shù)尚未開(kāi)發(fā)應(yīng)用于車輛行星變速器。因此,我們啟動(dòng)了一個(gè)研究項(xiàng)目以認(rèn)識(shí)如何得到可靠的布局。基于這個(gè)目的,我們測(cè)試了多種幾何結(jié)構(gòu)。允許的應(yīng)力值被設(shè)為材料、潤(rùn)滑和滑磨的函數(shù),然后研究合適的布局理論。這些測(cè)試在調(diào)整過(guò)的齒輪試驗(yàn)臺(tái)上進(jìn)行,見(jiàn)圖17。試驗(yàn)臺(tái)有一組直齒輪和一組螺旋齒輪。一根軸沒(méi)有軸向力支撐,軸向力由推力環(huán)承受。因此推力環(huán)的軸向載荷是扭矩的函數(shù)。額外的軸向力通過(guò)一個(gè)附加裝置提供,這樣就能再推力環(huán)上得到不同的載荷。需要注意的是,推力環(huán)與齒輪的損壞條件是一樣的,即磨損、疲勞等。在基礎(chǔ)開(kāi)發(fā)成功后,我們?yōu)樯逃密囋O(shè)計(jì)了推力錐并測(cè)試。行星齒輪組由直齒輪改為螺旋齒輪后,16輪商用車變速器的噪聲有顯著降低,見(jiàn)圖18。3風(fēng)險(xiǎn)最優(yōu)文件ca品種methodssoon-rox在一些變速器中,傳動(dòng)軸和中心線不是平行的,轉(zhuǎn)矩的傳遞途徑多種多樣,如通過(guò)錐齒輪或冠齒輪,萬(wàn)向軸或錐形漸開(kāi)線齒輪(斜面體齒輪)。錐形漸開(kāi)線齒輪尤其適用于小軸夾角(小于15度)的情況,因?yàn)樗子谥圃?設(shè)計(jì)和安裝。這種齒輪可用于交叉軸或斜軸變速器,也可用于具有零背隙平行軸的變速器。由于錐角的選擇與軸交叉角無(wú)關(guān),錐形漸開(kāi)線齒輪也可與柱齒輪配對(duì)使用。斜面體齒輪可作為外齒輪或內(nèi)齒輪,因此配對(duì)的可能性很多,為設(shè)計(jì)者提供了很大自由度。Conicalgearsarespurorhelicalgearswithvariableaddendumcorrection(tooththickness)acrossthefacewidth.Theycanmeshwithallgearsmadewithatoolwiththesamebasicrack.Thegeometryofbeveloidsisgenerallyknown,buttheyhavesofarrarelybeenusedinpowertransmissions.Neithertheloadcapacitynorthenoisebehaviorofbeveloidshasbeenexaminedtoanygreatextentinthepast.Standards(suchasISO6336forcylindricalgears),calculationmethods,andstrengthvaluesarenotavailable.Therefore,itwasnecessarytodevelopthecalculationmethod,obtaintheloadcapacityvalues,andcalculatespecificationsforproductionandqualityassurance.Inthelast15years,ZFhasdevelopedvariousapplicationswithconicalgears/6/:*Marinetransmissionswithdown-angleoutputshafts,Fig.19*Steeringtransmissions*Low-backlashplanetarygears(crossedaxesangle1…3°)forrobots*Transfergearsforcommercialvehicles(dumper)*AutomaticcartransmissionsforAWD,Fig.20Toputitsimply,abeveloidisaspurgearwithcontinuouslychangingaddendummodificationacrossthefacewidth,asshowninFig.21.Toaccomplishthis,thetoolistiltedtowardsthegearaxisbytherootconeangle/6/.Thedifferingbasecirclesfortheleftandrightflanksleadtoasymmetricaltoothprofilesathelicalgears,Fig.21.Manufacturingwitharack-typecutterresultsinatoothrootconewithachoosenrootconeangle.Theaddendumangleisdesignedsothattipedgeinterferenceswiththematinggearareavoidedandamaximallylargecontactratioisobtained.Thus,adifferingtoothheightresultsacrossthefacewidth.Duetothegeometricdesignlimitsforundercutandtipformation,thepossiblefacewidthdecreasesastheconeangleincreases.Sufficientlywell-proportionedgearingispossibleuptoaconeangleofapprox.15°.錐形齒輪是表面寬度內(nèi)具有多種齒頂高修正(齒厚度)的直齒輪或螺旋齒輪。它們可與相同基準(zhǔn)齒條工具制造的所有齒輪嚙合。斜面齒輪的幾何特點(diǎn)眾人皆知,但至今為止很少用于動(dòng)力傳遞。在過(guò)去沒(méi)有詳細(xì)討論過(guò)斜面齒輪的載荷能力和噪聲性能。也沒(méi)響應(yīng)標(biāo)準(zhǔn)(如柱齒輪標(biāo)準(zhǔn)ISO6336),計(jì)算方法和強(qiáng)度數(shù)據(jù)。因此,有必要研究計(jì)算負(fù)載能力的方法,以及保證生產(chǎn)和質(zhì)量的詳細(xì)規(guī)格。在過(guò)去15年中,ZF開(kāi)發(fā)了多種錐齒輪的應(yīng)用:*船用斜下輸出軸變速器,圖19。TheusablefacewidthonthebeveloidgearingislimitedbytipformationontheheelandundercutonthetoeasshowninFig.21.Thegreatertheselectedtoothheight(inordertoobtainalargeraddendummodification),thesmallerthetheoreticallyuseablefacewidthis.Undercutonthetoeandtipformationontheheelresultfromchangingtheaddendummodificationalongthefacewidth.Themaximumusablefacewidthisachievedwhentheconeangleonbothgearsofthepairingisselectedtobeapproximatelythesamesize.Withpairshavingasignificantlysmallerpinion,asmallerconeanglemustbeusedonthispinion.Tipformationontheheelislesscriticalifthetipconeangleissmallerthantherootconeangle,whichoftenprovidesgooduseoftheavailableinvoluteonthetoeandforsufficienttipclearanceintheheel.Attheuncorrectedgearing,thereisonlyonepointincontactduetothetiltingoftheaxes,Fig.22.Thegapingthatresultsalongthepotentialcontactlinecanbeapproximatelydescribedbyhelixcrowningandflanklineangledeviation.Crossedaxesresultinnodifferencebetweenthegapsontheleftandrightflanksonspurgears.Withhelicalgearing,theresultinggapingisalmostequivalentwhenbothbeveloidgearsshowapproximatelythesameconeangle.Thedifferencebetweenthegapvaluesontheleftandrightflanksincreasesasthedifferencebetweentheconeanglesincreasesandasthehelixangleincreases.Thestressatthebeveloidgearscanalsobecalculatedusingthefinite-elementmethod.Fig.23showsthecomputer-generatedmodelinthetoothmeshsectionandthestressdistributioncalculatedwithPERMASonthedrivengearinameshposition.Thecalculationwascarriedoutformultiplemeshpositionsandthetransmissionerrorcanbedeterminedfromtherotationofthegears.*轉(zhuǎn)向變速器*機(jī)器人用小齒隙行星輪(軸交叉角1～3度)*商用車(自卸車)分動(dòng)齒輪*全輪驅(qū)動(dòng)轎車自動(dòng)變速器簡(jiǎn)言之,斜面體齒輪是齒頂高修正沿表面寬度連續(xù)變化的直齒輪,如圖21。為實(shí)現(xiàn)這一點(diǎn),制造該齒輪時(shí),工具以根錐角向齒輪傾斜。圖21中,左右側(cè)基圓的不同使螺旋齒輪的齒廓不對(duì)稱。用齒條銑刀制造時(shí)可選擇根錐角。齒頂角的設(shè)計(jì)應(yīng)使齒尖邊緣不與配對(duì)齒輪接觸,且獲得最大嚙合率。因此,沿表面寬度的齒高不同。由于幾何設(shè)計(jì)上對(duì)下部切割和齒尖構(gòu)成的限制,表面寬度隨錐角的增大而減小。比例合適的齒輪錐角可達(dá)15度。斜面齒輪中可用的表面寬度被齒輪大端構(gòu)造和小端根切所限制,如圖21。為獲得更大齒頂高修正,所選齒高越高,理論可用的表面寬度越小。沿表面寬度改變齒頂高修正形成了小端根切和大端齒尖構(gòu)形。Aback-to-backtestbenchwithcrossedaxes,uponwhichgearpairsfromAWDtransmissionsweretested,wasusedtodeterminetheloadcapacity,Fig.24.Differentcorrectionswereproducedonthetestgearsinordertoascertaintheirinfluenceontheloadcapacity.TherewasgoodcorrelationbetweentheloadcapacityinthetestandtheFE(finiteelement)results.Particularlynoteworthyisanadditionalshiftoftheloadpatterntowardstheheelduetotheincreasedstiffnessinthisarea.Thisshiftisnotdiscernableinthecalculationwiththesubstitutecylindricalgearpair.Simultaneoustotheloadcapacitytests,measurementsofthetransmissionerrorandrotationalaccelerationwereconductedinauniversalnoisetestbox,Fig.25.Inadditiontotheloadinfluence,theinfluenceofadditionalaxistiltonthenoiseexcitationwasalsoexaminedinthesetests.Withregardtothisaxistilt,nolargeamountofsensitivityinthetestedgearsetswasfound.Onlygeneratingmethodscanbeusedtoproducethebeveloidgearing,becausetheshapeofthetoothprofilechangessignificantlyalongthefacewidth.Hobsaretheeasiesttouseforpre-cutting.Gearplaningwouldtheoreticallybeuseableaswell;however,thekinematicsrequiredmakesthisnotreallyfeasibleonexistingmachines.Internalconicalgearscanthenonlybepreciselymanufacturedwithpinion-typecuttersifthecutteraxisisparalleltothetoolaxisandtheconeiscreatedbychangingthecenterdistance.Iftheinternalgearismanufacturedwithatiltedpinioncutteraxissuchasusedforcrowngears,thisresultsinahollowcrowningandaprofiletwistwithoutcorrectivemovements.Thesedeviationsaresmallenoughtobeignoredforminorconeangles.Forfinalprocessing,continuousgenerationgrindingwithagrindingwormappearstobethebestoption.Withtheassistanceofthemanufacturingsimulation,machinesettingsandmovementswithcontinuousgenerationgrindingaswellastheproducedprofiletwistcanbeobtained.當(dāng)配對(duì)齒輪的錐角近似相等時(shí),可獲得最大可用表面寬度。如果要和小齒輪配對(duì),必須選用較小的錐角。如果尖端錐角比根錐角要小,則大端齒尖構(gòu)型不起關(guān)鍵作用,這時(shí)小端漸開(kāi)線和大端齒尖凈空得以充分利用。對(duì)于不正確的齒輪,由于軸的傾斜,接觸點(diǎn)只有一個(gè),見(jiàn)圖22。沿著可能接觸線的間隙可大致用螺旋鼓和側(cè)線角偏差描述。軸的交叉使直齒輪左右兩側(cè)間隙相同。在螺旋齒輪中,當(dāng)兩個(gè)斜面齒輪錐角大致相等時(shí),產(chǎn)生的間隙幾乎相同。當(dāng)錐角差變大或螺旋角變大時(shí),左右側(cè)間隙差也變大。斜面齒輪處的應(yīng)力也能用有限元法計(jì)算。圖23所示為計(jì)算機(jī)生成的齒嚙合區(qū)的模型,以及PERMAS計(jì)算得到的驅(qū)動(dòng)齒輪嚙合點(diǎn)出應(yīng)力分布情況。計(jì)算在多個(gè)嚙合點(diǎn)進(jìn)行,傳遞誤差可由齒輪的轉(zhuǎn)動(dòng)得到。為檢測(cè)負(fù)載能力,AWD變速器的齒輪對(duì)在一具有交叉軸的背靠背臺(tái)架上測(cè)試,見(jiàn)圖24。4wictin兩相關(guān)interfigre能traftingfi選用Specificproceduresbasedonclassicmethodsareusedforfasttransmissiondesign.Heretheknowledgeofnear-seriesgear,shaftandbearingstrengthvaluesisimportant.WedeterminedsuitableS/Ncurvesfortherespectivetransmissiontypes,whichwecanuse.Today,finiteelementproceduresincreasinglylendthemselvestotransmissionoptimization,asmodernsoftwareandhardwareenhancethepossibilitiesinherenttothismethod/7/.Weusethempredominantlyforgears,shafts,bearings,andcases.Afewexamplesshouldillustratethis.Forexample,itispossibletodeterminethe