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Development

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DevelopmentDevelo

    Development

    1552Xiangetal/JZhejiangUnivSciA20089(11):1552-1559 ;JournalofZhejiangUniversitySCIENCEA

    ;ISSN1673-565X(Print);ISSN18621775(Online)

    ;wwwzjueducn~zus;wwwspringerlinkcom

    ;Email:jZUS@zjueducn

    ;Developmentofan-typeactuatorforenhancing

    ;high--speedelectro--pneumaticejectorvalveperformance ;ZhongXIANG

    ;,

    ;HaoLIU

    ;,

    ;Guo.LiangTAO,JunMAN,WeiZHONG

    ;(StateKeyLaborato~ofFluidPowerTransmissionandControl,ZhejiangUniversity,Han

    gzhou310027,China)

    ;E-mail:zju_xiang@hotmailcorn;hliu2000@zju.edu.cn ;ReceivedMay6,2008;revisionacceptedAug.25,2008

    ;Abstract:Anovele-typesolenoidactuatorisproposedtoimprovethedynamicresponseofe

    lectropneumaticejectorvalvesby

    ;reducingmovingmassweight.Afiniteelementanalysis(FEA)modelhasbeendevelopedt

    odescribethestaticanddynamic

    ;operationsofthevalves.ComparedwithaconventionalEtypeactuator,theproposed8-typeactuatorreducedthemovingmass

    ;weightbyalmost65%withoutsignificantlossofsolenoidforce,andreducedtheresponseti

    me(RT)typicallyby20%.Prototype

    ;valvesweredesignedandfabricatedbasedontheproposedg-typeactuatormode1.Anexpe

    rimentalsetupwasalsoestablishedto

    ;investigatethedynamiccharacteristicsofvalves.Theexperimentalresultsofthedynamics

    ofvalvesagreedwellwithsimulations,

    ;indicatingthevalidityoftheFEAmode1.

    ;Keywords:,一

    typeactuator,Highspeedelectropneumaticejectorvalve,Finiteelementmethod,Dynamicsimulationandcx

    ;periment

    ;doi:10.1631/jzus.A0820350Documentcode:ACLCnumber:TM15;TH138 ;INTR0DUCTION

    ;Withadvantagesoflowcost.antipollution

    ;ability,highflowrategain,smallsizeandsimple

    ;structure(Topqueta1.,2006;Khaneta1.,2007),

    ;high..speedelectro..pneumaticejectorvalveshave

    ;attractedconsiderableattentioninseveralareasof ;modemindustry.Theyhavebeenusedinsorting ;parts,flappingcontrolsystemsandothersystemsfor ;gluing,dosingandpackagingwherediscretecyclic, ;linearorrotatingmotionsandaverylonglifetimeare

    pneumatic ;required.Thesemodemhigh-speedelectro

    ;valveapplicationsneedfurtherimprovementsin-

     ;cludinghigheroperatingspeed,improvedrepro

    ;ducibilityoftheopeningandclosingphase,and ;weight,volumeandcostreduction(Ertleta1.,2003). ;Therehavebeenmanydevelopmentsinfast

    ;responseactuatorsoverthepasttwodecades.First, ;Correspondingauthor

    ;ProjectsupposedbytheDoctoralFundofMinistryofEducationof ;China(No.20070335133)andtheEducationalCommissionof ;Zh@angProvinceNo.20070057),China

    ;Seillyr1979;19811studiedtwokindsofsolenoid ;actuators,calledHelenoidandColenoid.Further ;researchthenfollowed.aimedatimprovingthedy

    ;namicresponseofactuatorsbydevelopingnewkind ;ofsolenoidsorireprovingtheoldones.Schechter ;fl982)developedakindoffastresponsemultipole ;solenoidactuatorwitha2.msresponsetimefRT1. ;Kushidar1985)developedadisktypesolenoidac

    ;tuator(calledDISOLE)withanRToflessthan1ms. ;Recently,piezOtranslatorshavealsobeendeveloped ;foruseasactuatorsofejectors.ZhaoandJones(1991) ;developedafastresponseelectropneumaticpower

    ;converterbycombiningastackedDiezotranslator ;flapperasadrivestageandabackpressurestagefor ;generatingtheoutput.Lee(1999)designedfastac

    ;tuatorsusingmultilayerstackedalkalihalideelec

    ;trostrictivematerialsforfuelinjection.Although ;theseproposedactuatorshavefairlygoodperforlTl

    ;ancestheyarenotpopularinthedesignof

    ;high..speedelectro..pneumaticejectorvalvesbecause ;oftheirlargesize,highcostorcomplexstructure. ;Theyarenotwel1suitedtosomeofthecharacteris

    ;Xiangetal/JZhejiangUnivSciA20089(11):1552-1559 ;ticsinherentinhigh-?speedelectro--pneumaticejector ;valves,includingsmallstrokelength(O.05-0.10inin) ;andlowworkingpressure(1essthan1.O×10.Pa). ;Neitheraretheywellsuitedtotheneedsofindustrial ;applicationsincludingsmallsize,lowcost,large

    ;forceproduction,lackofoperationmaintenance ;undercontinuousdutycyclesat150-300Hzand ;multibillioncycleoperation(inexcessoffivebillion ;cycles)(Khaneta1.,2007).

    ;Onthecontrary,classicalC-typeandE-type ;actuatorsarestillfavoredforuseasejectorvalve ;actuatorsbecauseoftheirsimplicityandhighholding ;forcecapability.Forexample,Fig.1showsasche

    ;maticcrosssectionthroughatypicalactuatorthathas ;beenusedinanejectorvalve.Thesymbols(e…g,

    ;n)usedinFig.1andFig.2(seeinnextsection)for ;dimensionalparametersnormallyconsistofaprefix ;character.,f0rlengthanddfordiameter.andasub

    ;scripttodifferentiatefromeachother.Itisobvious ;thattheactuatorshowedinFig.1isessentiallyan ;E.tVpeactuatorthatconsistsofanexcitationcoil ;woundaroundamagneticEcorestatorandadisk

    ;steelarmature(movingmass).Thearmaturewil1be ;caughtorreleasedbyenergizingordeenergizingthe

    ;woundcoil.Thesolenoidforceproducedbytheac

    ;tIlatorisneededtoovercomethereactionforceto ;whichthearmatureissubjectedasaresultof ;highpressureairflowingthroughthevalve.As ;provedbySchechter(1982)andSeilly(1979;1981), ;withanE-type(orCtype)actuator,thelargerthe

    ;solenoidforcerequired.the1owertheaccelerationof ;thearmature(movingmass).Thispresentsasub

    ;stantialchallengetoobtainingfurtherimprovementin ;thevalvedynamicswithinitscompactpackaging ;size.

    ;MagneticEcoreCoilArmature

    ;Fig.1Definitionsofdimensionalparametersforacon- ;ventionalE.corestatoranddiskarmature

    ;1553

    ;ThisPaDerdescribesthedevelopmentofan

    ;e-typeactuator(incrosssection,theshapeofthe ;actuatorlooksIikethecharacter1tobalancethe

    ;increasedsolenoidforceandthedecreasedarmature ;accelerationinherentinE.typeactuatorstoenhance ;theperformanceofelectropneumaticejectorvalves.

    ;Thefiniteelementanalysis(FEA)methodisusedto ;modelandsimulatetheactuatorandthefabricated ;ejectorvalve.Steadystateanddynamicresponse ;characteristicsofE.typeande-typeactuatorsare

    ;thoroughlycompared.Finally,simulateddynamic ;displacementandcurrentresultsoftheactuatorare ;contrastedwiththeexperimentalresults.respectively ;Asanexampleofapplication,thenewlydeveloped ;high-speedpneumaticejectorvalvesareusedinthe ;ejectionsystemsofhigh?speedopticalfoodsorting ;machines.

    ;FINITELEMENTANALYSISMODELLING

    ;Descriptionofthe,一typeactuatoranddesignof

    ;theprototypevalve

    ;Fig.2aillustratestheschematicstructureofthe ;proposede-typeactuator.ComparedwiththeE-type ;actuator(Fig.11.a’coreshoulder’isintroducedinto

    ;the,一typeactuatorstructure.Thestructuraldimen

    ;sionsofbothactuatorsarealmostthesamewhilethe ;armature(movingmass)weightofthee-typeactua- ;torisreducedconsiderably.Asprovedbelow.the ;solenoidforceproducedbyane-typeactuatoris ;almostthesameasthatproducedbyanE..typeac.. ;tuator.butthedynamicresponseperformanceofthe ;e-typeactuatorismuchimproved.

    ;Fig.2bshowsaschematiccrosssectionofthe ;fabricatedprototypevalve.Thevalvecanbedivided ;intothreemajorbodies(bodiesI.II.III).BodyI ;consistsofamagnetic.core.awoundcoilanda

    ;plasticring,andprovidesanairinletport.Awire ;tunnelisalsodrilledinit.BodyIIhasacircular ;chamberinthecentertohousethearmature.The ;diameterofthechamberisdesignedtobeslightly ;biggerthanthatofthearmaturetoensurethatthe ;armaturecanmovefreely.Foursemicircularslotsare ;distributedevenlyalongtheinnercircumferenceof ;bodyIItoimprovetheflowrateofthevalve.Body ;IIIprovidesanairoutletport.shownindetailin ;Fig.2c(topview).Thecoi1consistsof150turnsof ;1554Xiangotal/dZhejiangUnivSciA20089(11):15521559

    ;isolatedcopperwirewitharesistanceof3.2Q.ItiS ;directlywoundonthemagneticcoretoimprovethe ;heat.sinkingcapacityofthevalve.A1lthreebodies ;aremadeofhardaluminumandareioinedtogether ;withfourhexagonalsocketcountersunkheadscrews. ;ThevalveiSsealedwithOringsorrubbersheet.

    ;Contactfaces.suchasthelowerfaceofthearmature ;MagneticE-coreCoilCoreshoulderArmature

    ;(a) ;

    ;l_f}.\lI

    ;\

    ;,

    ;××\,,,,,,

    -?二 ;U-1

    ;l,Il\

    ;__j-, ;\

    ;t

    ;()

    ;(c) ;.

    ;(a) ;,(b)

    ;()

    ;,

    ;.i

    ;.1

    ;.il ;1i. ;11

    ;.1ll

    ;1.1 ;.1l ;??

    ;l

    ;bOthtV’. ;

    ;-

    ;()

    ;() ;(Q) ;()

    ;(N’)

    ;()

    ;8.I2 ;×6

    ;3.2 ;.10 ;1.8×1O

    ;1.× ;Xiangeta1./JZhejiangUnivSciA20089(11):1552-1559

;Magneticfields~ength(xl0A/m)

    ;Fig.3InitialmagnetizationcurveforEtypeand-type

    ;actuators

    ;simulatebothactuators(Figs.1and21.Assumingthat ;thematerialusedfortheactuatorisisotropicandits ;hysteresiscanbeneglected,electromagneticfields ;aregovernedby.Maxwellequations(Eqs.(1)(4))

    ;withdisplacementcurrentsignored(quasistationary ;limit)whiletheconstitutiveequationisexpressedas ;Eq.(5)(Nannapaneni,2004):

    ;×H(r,,)=J(r,,),

    ;V?B(r,)=0,

    ;v×(r,f):OB

    ;_

    ;(r,t)

    ;,

    ;r

    ;.

    ;E():,

    ;=vB.J=E.

    ;(1)

    ;(2)

    ;(3)

    ;(4)

    ;(5)

    ;whereisthemagneticfieldintensity,istheradial ;coordinateinthecylindricalcoordinatesystem.Bis ;themagneticfluxdensity.Jisthecurrentdensity,E ;istheelectric.fieldintensity.Pisthevolumetric ;chargedensity,40istheelectricpermittivityoffree ;space.1,isthematerialreluctivity,andoistheelec

    ;tricalconductivity.

    ;ByintroducingmagneticvectorpotentialAand ;electricalscalarpotential,andcombiningwith ;CoulombgaugeconditionandDirichletboundary ;condition.Maxwellequationscanbeexpressedas ;(PawlakandNehl,1988;Khaneta1.,2007): ;B=VxA,(6)

    ;V?

    ;(8tVI/..

    ;×(vVxA)=l,0.4+dfi×(×)

    ;,(8)

    ;fdf

    ;1555

;whereisthearmaturedisplacement.

    ;Inthetransientcasewithmotionanadditional ;circuitequationshouldbesimultaneouslysolved ;withthepartialdifierentia1equationofthemagnetic ;field.Thefollowingvoltageequationisusedto ;coupletheelectricandmagneticmodels:

    +dd0L(6,I), ;)=/R+

    ;whereU,j,R,Laretheexternalenergizingvoltage, ;coilcurrent.coilresistanceandwoundcoilreluc