制动器外文翻译盘式制动器试验台上测量空气中磨损颗粒.docx

制动器外文翻译盘式制动器试验台上测量空气中磨损颗粒.docx

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制动器外文翻译盘式制动器试验台上测量空气中磨损颗粒

本科生毕业设计（论文）外文翻译

外文题目：

Adiscbraketeststandformeasurementofairbornewearparticles

译文题目：

盘式制动器试验台上测量空气中磨损颗粒

学生姓名：

专业：

车辆工程

指导教师姓名：

评阅日期：

Adiscbraketeststandformeasurementof

airbornewearparticles

ABSTRACT

Duringbraking,thereiswearonboththerotorandthepads.Thisprocessgeneratesparticlesthatmaybecomeairborne.Infieldtests,itisdifficulttodistinguishtheseparticlesfromothersinthesurroundingenvironment.Therefore,alaboratoryteststandhasbeendesignedwhichallowscontrolofthecleanlinessofthesurroundingair.Theteststandconsistsofafrontrightbrakeassemblymountedinasealedchamber.Abrakingloadisappliedbyapneumaticsystemandtherotor,whichhasbeenpre-conditionedwitharustlayertosimulateacarstandingparkedovernightinawetenvironment,isdrivenbyanelectricmotor.Thenumberandsizeofairbornewearparticlesarethenmeasured.Thisexperimentalset-uphasbeenverifiedbyaninitialtestseriesperformedatlow

brakingloads.Theresultssuggestthatthisteststandcanbeusedtostudyrustlayerremovalfromtherotor.

keywords:

wear;airborneparticles;discbrake;teststand;rustlayer

INTRODUCTION

Manystudieshaveshownanassociationbetweenadversehealtheffectsandtheconcentrationofairborneparticlesintheatmosphere.1–3Inurbanenvironments,airborneparticlescancomefromdifferentsources,e.g.demolitionandconstruction,4resuspendedroaddust,5wheel-to-railcontact,6,7car-to-roadcontact8,9anddiscbrakes.10,11Duringbraking,boththebrakepadsandrotorsareworn,generatingwearparticles.Someoftheseparticlesaredepositedonthebrakehardware,andothersbecomeairborne.

Furthermore,toensurerobustbrakeperformance,somebrakesystemsmayrequirethepadstofrequentlybeinlowpressurecontactwiththerotor.Thisdraggingmayremoveanyrustlayer,whichmaybuildstandingparkedovernightinawetenvironment,fromtherotorandkeepthecontactsurfacesclean.However,theresultingdragtorqueincreasesthefuelconsumptionandgenerateswearparticles,becausethepadsarestillincontactwiththerotoraftertherustlayerhasbeenremoved.Itisthereforedesirabletoreducethedraggingwithoutaffectingtheperformanceofthebrakes.

Whenmeasuringairbornebrakeparticlesinfieldtests,itcanbedifficulttodistinguishthemfromothertraffic-generatedaerosols.Therefore,itmaybepreferabletouselaboratoryteststhatallowcontrolofthecleanlinessofthesurroundingair.Althoughseveralteststandshavebeenbuilttostudywearandfrictionatthepad-to-rotorinterface,fewstudies12,13havefocusedonwearparticles.Inalaboratoryteststand,thecleanlinessofthesurroundingaircanbecontrolled,enablingmoreaccuratestudyofairbornebrakewearparticles.Withthisinmind,alaboratorycomponentteststand

hasbeendesignedtomeasurethenumberandsizeofairbornewearparticlesgeneratedbydiscbrakes.Thepurposeofthispaperwastodescribethisteststandandpresenttheresultsofafirsttestseriestoverifytheexperimentalset-up.Thesetestsfocusonrustlayerremovalatlowbrakingloads.

EXPERIMENTALSET-UP

Inthisteststand,afrontrightbrakeassemblyfromapassengercarisused.Thefrontrightbrakeassemblyconsistsofaknuckle,thewheelbearingandthediscbrakeassembly.Thediscbrakeassemblyinturnconsistsofaventilatedrotor,aslidingcaliperwithasinglepistonandtwobrakepads

（Figure1）.ThefingersidebrakepadincludesaK-typethermocouplethatmeasuresthetemperaturenearthefingersidepad-to-rotorcontact.AschematicdiagramoftheteststandisgiveninFigure2.Anelectricdirectcurrentmotor（K）with

anominaltorqueof191Nmdrivestherotor,andapneumaticsystem（M）connectedtothefrontrightbrakeassembly（H）isusedtoapplyacontrolledbrakingload.Whenthebrakeisapplied,themotorcontinuestodrivethesystematastationaryrotationalspeed,i.e.thetestsystemthrottlesandbrakes

atthesametime.Adriveshaft（L）transfersthetorquefromthemotortothewheelbearing,whichinturnrotatesthedisc.Themotorandthedriveshaftareconnectedbyafixedcoupling,andthewheelbearingandthedriveshaftareconnectedbyasplinedcoupling.Theknuckleismountedtoasuspension

device.Asealingchamber（G）sealsthefrontrightbrakeassemblyfromthesurroundings.Theelectricmotorisbalancedwithbearingsoneachend.Theappliedtorqueonthemotorismeasuredusingacalibratedstraingaugeforcesensormultipliedbythedistancefromthemotorcentre,withanaccuracyof±2.2%.Therotationalspeedofthediscismeasuredbyabuilt-inHalleffectsensorinthewheelbearing,with48pulsesperrevolution.Apneumaticsystemgeneratescontrolledlowpressureleve