机械专业论文中英文对照.docx

机械专业论文中英文对照.docx

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机械专业论文中英文对照

GearboxNoise

CorrelationwithTransmissionErrorandInfluenceofBearingPreload

DoctoralThesisinMachineDesign

TRITA-MMK2008：

19

ISSN1400—1179

ISRN/KTH/MMK/R-08/19-SE

DepartmentofMachineDesign

RoyalinstituteofTechnology

SE−10044Stockholm，Sweeden

©MatsÅkerblom2008

ABSTRACT

Thefiveappendedpapersalldealwithgearboxnoiseandvibration。

Thefirstpaperpresentsareviewofpreviouslypublishedliteratureongearboxnoiseandvibration。

Thesecondpaperdescribesatestrigthatwasspeciallydesignedandbuiltfornoisetestingofgears。

Finiteelementanalysiswasusedtopredictthedynamicpropertiesofthetestrig,andexperimentalmodalanalysisofthegearboxhousingwasusedtoverifythetheoreticalpredictionsofnaturalfrequencies.Inthethirdpaper,theinfluenceofgearfinishingmethodandgeardeviationsongearboxnoiseisinvestigatedinwhatisprimarilyanexperimentalstudy.Eleventestgearpairsweremanufacturedusingthreedifferentfinishingmethods。

Transmissionerror，whichisconsideredtobeanimportantexcitationmechanismforgearnoise，wasmeasuredaswellaspredicted。

Thetestrigwasusedtomeasuregearboxnoiseandvibrationforthedifferenttestgearpairs.Themeasurednoiseandvibrationlevelswerecomparedwiththepredictedandmeasuredtransmissionerror.Mostoftheexperimentalresultscanbeinterpretedintermsofmeasuredandpredictedtransmissionerror.However，itdoesnotseempossibletoidentifyonesingleparameter，suchasmeasuredpeak—to—peaktransmissionerror，thatcanbedirectlyrelatedtomeasurednoiseandvibration.Themeasurementsalsoshowthatdisassemblyandreassemblyofthegearboxwiththesamegearpaircanchangethelevelsofmeasurednoiseandvibrationconsiderably。

Thisfindingindicatesthatotherfactorsbesidesthegearsaffectgearnoise。

Inthefourthpaper,theinfluenceofbearingendplayorpreloadongearboxnoiseandvibrationisinvestigated。

Vibrationmeasurementswerecarriedoutattorquelevelsof140Nmand400Nm,with0。

15mmand0mmbearingendplay,andwith0。

15mmbearingpreload.Theresultsshowthatthebearingendplayandpreloadinfluencethegearboxvibrations。

Withpreloadedbearings,thevibrationsincreaseatspeedsover2000rpmanddecreaseatspeedsbelow2000rpm,comparedwithbearingswithendplay。

Finiteelementsimulationsshowthesametendenciesasthemeasurements.Thefifthpaperdescribeshowgearboxnoiseisreducedbyoptimizingthegeargeometryfordecreasedtransmissionerror。

Robustnesswithrespecttogeardeviationsandvaryingtorqueisconsideredinordertofindageargeometrygivinglownoiseinanappropriatetorquerangedespitedeviationsfromthenominalgeometryduetomanufacturingtolerances.Staticanddynamictransmissionerror，noise，andhousingvibrationsweremeasured。

Thecorrelationbetweendynamictransmissionerror,housingvibrationsandnoisewasinvestigatedinspeedsweepsfrom500to2500rpmatconstanttorque。

Nocorrelationwasfoundbetweendynamictransmissionerrorandnoise。

Staticloadedtransmissionerrorseemstobecorrelatedwiththeabilityofthegearpairtoexcitevibrationinthegearboxdynamicsystem.

Keywords：

gear，gearbox,noise，vibration，transmissionerror,bearingpreload.

ACKNOWLEDGEMENTS

ThisworkwascarriedoutatVolvoConstructionEquipmentinEskilstunaandattheDepartmentofMachineDesignattheRoyalInstituteofTechnology（KTH）inStockholm。

TheworkwasinitiatedbyProfessorJackSamuelsson（VolvoandKTH）,ProfessorSörenAndersson（KTH），andDr。

LarsBråthe（Volvo）.ThefinancialsupportoftheSwedishFoundationforStrategicResearchandtheSwedishAgencyforInnovationSystems–VINNOVA–isgratefullyacknowledged.VolvoConstructionEquipmentisacknowledgedforgivingmetheopportunitytodevotetimetothiswork。

ProfessorSörenAnderssonisgratefullyacknowledgedforexcellentguidanceandencouragement。

IalsowishtoexpressmyappreciationtomycolleaguesattheDepartmentofMachineDesign，andespeciallytoDr.UlfSellgrenforperformingsimulationsandcontributingtothewritingofPaperD，andDr.StefanBjörklundforperformingsurfacefinishmeasurements。

ThecontributionstoPaperCbyDr.MikaelPärssinenarehighlyappreciated.AllcontributionstothisworkbycolleaguesatVolvoaregratefullyappreciated。

1INTRODUCTION

1。

1Background

Noiseisincreasinglyconsideredanenvironmentalissue.Thisbeliefisreflectedindemandsforlowernoiselevelsinmanyareasofsociety，includingtheworkingenvironment。

Employeesspendalotoftimeinthisenvironmentandnoisecanleadnotonlytohearingimpairmentbutalsotodecreasedabilitytoconcentrate,resultingindecreasedproductivityandanincreasedriskofaccidents.Quality,too，hasbecomeincreasinglyimportant。

Thequalityofaproductcanbedefinedasitsabilitytofulfillcustomers’demands。

Thesedemandsoftenchangeovertime，andthebestcompetitorsinthemarketwillsetthestandard.Noiseconcernsarealsoexpressedinrelationtoconstructionmachinerysuchaswheelloadersandarticulatedhaulers。

Thegearboxissometimesthedominantsourceofnoiseinthesemachines。

Evenifthegearnoiseisnottheloudestsource，itspurehighfrequencytoneiseasilydistinguishedfromothernoisesourcesandisoftenperceivedasunpleasant。

Thenoisecreatesanimpressionofpoorquality.Inordernottobeheard，gearnoisemustbeatleast15dBlowerthanothernoisesources,suchasenginenoise。

1.2Gearnoise

Thisdissertationdealswiththekindofgearboxnoisethatisgeneratedbygearsunderload.Thisnoiseisoftenreferredtoas“gearwhine"andconsistsmainlyofpuretonesathighfrequenciescorrespondingtothegearmeshfrequencyandmultiplesthereof，whichareknownasharmonics。

Atonewiththesamefrequencyasthegearmeshfrequencyisdesignatedthegearmeshharmonic，atonewithafrequencytwicethegearmeshfrequencyisdesignatedthesecondharmonic，andsoon。

Theterm“gearmeshharmonics”referstoallmultiplesofthegearmeshfrequency.Transmissionerror（TE）isconsideredanimportantexcitationmechanismforgearwhine。

Welbourn［1］definestransmissionerroras“thedifferencebetweentheactualpositionoftheoutputgearandthepositionitwouldoccupyifthegeardrivewereperfectlyconjugate.”Transmissionerrormaybeexpressedasangulardisplacementoraslineardisplacementatthepitchpoint。

Transmissionerroriscausedbydeflections，geometricerrors，andgeometricmodifications。

Inadditiontogearwhine，otherpossiblenoise-generatingmechanismsingearboxesincludegearrattlefromgearsrunningagainsteachotherwithoutload，andnoisegeneratedbybearings.Inthecaseofautomaticgearboxes,noisecanalsobegeneratedbyinternaloilpumpsandbyclutches.Noneofthesemechanismsaredealtwithinthiswork，andfromnowon“gearnoise"or“gearboxnoise”refersto“gearwhine"。

MackAldener［2］describesthenoisegenerationprocessfromagearboxasconsistingofthreeparts:

excitation,transmission,andradiation.Theoriginofthenoiseisthegearmesh,inwhichvibrationsarecreated（excitation），mainlyduetotransmissionerror。

Thevibrationsaretransmittedviathegears，shafts，andbearingstothehousing（transmission）。

Thehousingvibrates,creatingpressurevariationsinthesurroundingairthatareperceivedasnoise（radiation）。

Gearnoisecanbeaffectedbychanginganyoneofthesethreemechanisms。

Thisdissertationdealsmainlywithexcitation，buttransmissionisalsodiscussedinthesectionoftheliteraturesurveyconcerningdynamicmodels,andinthemodalanalysisofthetestgearboxinPaperB.TransmissionofvibrationsisalsoinvestigatedinPaperD，whichdealswiththeinfluenceofbearingendplayorpreloadongearboxnoise.Differencesinbearingpreloadinfluenceabearing'sdynamicpropertieslikestiffnessanddamping.Thesepropertiesalsoaffectthevibrationofthegearboxhousing。

1。

3Objective

Theobjectiveofthisdissertationistocontributetoknowledgeaboutgearboxnoise.Thefollowingspecificareaswillbethefocusofthisstudy:

1.Theinfluenceofgearfinishingmethodandgearmodificationsanderrorsonnoiseandvibrationfromagearbox。

2。

Thecorrelationbetweengeardeviations，predictedtransmissionerror，measuredtransmissionerror,andgearboxnoise.

3.Theinfluenceofbearingpreloadongearboxnoise。

4.Optimizationofgeargeometryforlowtransmissionerror，takingintoconsiderationrobustnesswithrespecttotorqueandmanufacturingtolerances。

2ANINDUSTRIALAPPLICATION−TRANSMISSIONNOISEREDUCTION

2.1Introduction

Thissectionbrieflydescribestheactivitiesinvolvedinreducinggearnoisefromawheelloadertransmission。

TheaimistoshowhowtheoptimizationofthegeargeometrydescribedinPaperEisusedinanindustrialapplication.Theauthorwasprojectmanagerforthe“noiseworkteam”andperformedthegearoptimization。

Oneoftherequirementswhendevelopinganewautomaticpowertransmissionforawheelloaderwasimprovingthetransmissiongearnoise.Theexistingpowertransmissionwasknowntobenoisy。

Whendrivingathighspeedinfourthgear，ahighfrequencygear—whinecouldbeheard。

Thustherewerenowdemandsforimprovedsoundquality。

Thetransmissionisatypicalwheelloaderpowertransmission，consistingofatorqueconverter，agearboxwithfourforwardspeedsandfourreversespeeds，andadropboxpartlyintegratedwiththegearbox。

Thedropboxisachainoffourgearstransferringthepowertotheoutputshaft。

Thegearsareengagedbywetmulti—discclutchesactuatedbythetransmissionhydraulicandcontrolsystem。

2。

2Gearnoisetargetforthenewtransmission

Experiencehasshownthattheh