《氣動(dòng)技術(shù)》雙語(yǔ)電子教案

PneumaticActuatorsForpower,motionandcontrol《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4

WUHANUNIVERSITYOFTECHNOLOGYLOGISTICSENG.DEPT.武漢理工大學(xué)物流工程系ContentsBasicconstructionFundamentaldesignsForceRodbucklingSpeedcontrolResponsetimesAirconsumptionSealsCushiondesignShockabsorbersStandardsMountingsInstallationNonrotationalguidingLockingandbrakingRodlesscylindersVariantsSpecialpurposeactuatorsTwinstrokePositionersImpactcylindersTypesofconstructionClickthesectiontoadvancedirectlytoitIntroduction《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～1IntroductionClickheretoinsertmovieIntroductionPneumaticactuatorsincludelinearcylindersandrotaryactuators.Theyaredevicesprovidingpowerandmotiontoautomatedsystems,machinesandprocesses.Apneumaticcylinderisasimple,lowcost,easytoinstalldevicethatisidealforproducingpowerfullinearmovement.Speedcanbeadjustedoverawiderange.Acylindercanbestalledwithoutdamage.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～1IntroductionAdverseconditionscanbeeasilytoleratedsuchashighhumidity,dryanddustyenvironmentsandcleaningdownwithahose.Theboreofacylinderdeterminesthemaximumforcethatitcanexert.Thestrokeofacylinderdeterminesthemaximumlinearmovementthatitcanproduce.Themaximumworkingpressuredependsonthecylinderdesign.VDMAcylindersworkupto16bar.Thrustiscontrollablethroughapressureregulator.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～1BasicConstruction1cushionseal2magnet3cushionsleeve4barrel5guidebush6rodandwiperseal7frontendcover8frontport9reedswitch10pistonrod11wearring12pistonseal13rearendcover14cushionscrew《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～1Fundamentaldesigns《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2FundamentaldesignsPneumaticactuatorsaremadeinawidevarietyofsizes,stylesandtypesincludingthefollowingSingleactingwithandwithoutspringreturnDoubleactingNoncushionedandfixedcushionedAdjustablecushionedMagneticRodlessRotaryClampingBellows《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2SingleactingspringreturnSingleactingcylindershaveapowerstrokeinonedirectiononlyNormallyinNormallyout《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2SingleactingnospringGravityorotherexternalforcetoreturntherod《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2DoubleactingDoubleactingcylindersusecompressedairtopowerboththeoutstrokeandinstroke.SuperiorspeedcontrolispossibleThereareNon-cushionedtypesFixedcushionedtypesAdjustablecushionedtypes《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2Doubleactingnon-cushionedNoncushionedcylindersaresuitableforfullstrokeworkingatslowspeed.Higherspeedswithexternalcushions《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2DoubleactingfixedcushionsSmallborelightdutycylindershavefixedcushions《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2D/Aadjustablecushionsprogressivelyslowsthepistonroddownoverthelastpartofstroke《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2DoubleactingmagneticAmagneticbandaroundthecircumferenceofthepistonoperatesreedswitchestoindicatepositionsofstroke.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RodlesscylindersContainthemovementproducedwithinthesameoveralllengthtakenupbythecylinderbody.Forexample,actionacrossaconveyorbelt,orforverticalliftinginspaceswithconfinedheadroom.Movementisfromacarriagerunningonthesideofthecylinderbarrel.Aslot,thefulllengthofthebarrelallowsthecarriagetobeconnectedtothepiston.Longsealingstripsontheinsideandoutsideofthecylindertubepreventlossofairandingressofdust.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RodlesscylinderDoubleactingwithadjustablecushions《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RotaryActuatorsUsedforturningcomponents,operatingprocesscontrolvalves,performingawristactioninroboticapplications.Provideangularreciprocatingrotationupto360oRotaryvanetypesRackandpiniontypes《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RotaryvaneDoubleactingwith270oangleofrotation《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RotaryrackandpinionDoubleactingrackandpinion《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2RotaryrackandpinionDoubleactingdoubletorque《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2ClampingCylindersForuseinconfinedspaceswhereonlyashortstrokeisrequired.Shortaxialoveralldimensionfortheirboresize.GenerallyusedinlightdutyapplicationsMostlyusedinsingleactingversions,butalsoavailableindoubleactingthrough-rodstyles《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2ClampingcylinderNormallyspringinstroked《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2ClampingcylinderDoubleactingdoubleendedpistonrod《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2BellowsBellowsaredurablesingleactingconcertinalikeactuators.Extendwheninflated.Providepowerfulshortstrokes.Haveallroundcomplianceallowingthemtobendinanydirection.Canbeusedasairspringsandareidealforinsulatingthevibrationofsupportedloads.Caution:themaximumextensionandcompressionofthebellowsmustbelimitedbyexternalrestraints.Thebellowsmustneverbepressurisedwhileunrestrainedasitwilloverextendandtheendplateislikelytobeblownfreeandcouldcauseseriousinjuries.Whenthebellowsisexhaustedtheloadmustbepreventedfromcrushingit.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2BellowsDoubleconvolutiontype《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～2Force《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3CylindersizingforthrustThetheoreticalthrust(outstroke)orpull(instroke)ofacylinderiscalculatedbymultiplyingtheeffectiveareaofthepistonbytheworkingpressure.Theeffectiveareaforthrustisthefullareaofthecylinderbore“D”.Theeffectiveareaforpullisreducedbythecrosssectionareaofthepistonroddiameter“d”.d

D

《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3CylindersizingforthrustIntheformula,Pisdividedby10toconvertbartoNewtonspersquaremillimetre(1bar=0.1N/mm2)WhereD=CylinderboreinmillimetresP=PressureinbarF=ThrustorPullinNewtonsThrustF=D24P10Newtons《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3CylindersizingforthrustPullingforceFwillbelessthanthethrustduetothearealosttothepistonrodWhereD=Cylinderboreinmillimetresd=PistonroddiameterinmillimetresP=PressureinbarF=ThrustorPullinNewtonsPullF=(D2-d2)P40Newtons《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3CylindersizingforthrustExample;findthetheoreticalthrustandpullofa50mmborecylindersuppliedwithapressureof8bar.1571Newtons1319NewtonsThrustF=502.840PullF(502-202).840===《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3OpposingspringforceCalculatingthethrustorpullofsingleactingcylinderswithaspringismorecomplicated.Thespringforceopposingthethrustorpullwillprogressivelyincreaseasmoreofthestrokeisachieved.Thismustbesubtractedtofindthetheoreticalforce.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3Tableofthrustandpullss/aTablesofcylinderforcescanbefoundincataloguesThevaluesshownhereareforaworkingpressureof6barForanotherpressureinbar,multiplythethrustvalueinthetablebythatpressurethendivideby6CylinderboremmThrustNat6barMinPullofspringN10373125941610572016514252582332438274069939501102486317606780289286100458399《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3Tableofthrustandpullsd/aCylinderboremm(inches)Pistonroddiametermm(inches)ThrustNat6barPullNat6bar8330251044739126675016612010320818815825102942463212482414401675363344.45(1.75)169318105020117898963201870168176.2(3)252736244180253015272110025471244181253273636881152.4(6)(11/2)1094410260160401206311309200401884918095250502945228274304.8(12)(21/4)4377942240320634825446384355.6(14)(2/14)5958858049ThepullvaluesarelowerduetotheannularareaofthepistonThevaluesshownhereareforaworkingpressureof6barForanotherpressureinbar,multiplythethrustvaluesinthetablebythatpressurethendivideby6《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3ThrustWhenestimatingtherelativethrustsofcylinderswithdifferentboresizes,itcanbeusefultorememberthatthrustincreaseswiththesquareofthediameter.InotherwordsifyoudoubletheboreyouwillquadruplethethrustThisis4timestheareaofthis2dd《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3UseableThrustWhenselectingacylindersizeandsuitableoperatingpressure,anestimationmustbemadeoftheactualthrustrequired.Thisisthentakenasapercentageofthetheoreticalthrustofasuitablysizedcylinder.Thepercentagechosenwilldependonwhethertheapplicationrequiresstaticordynamicthrust.Staticthrustattheendofmovementforclamping.Dynamicthrustduringmovementforlifting.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3ClampingApplicationsInaclampingapplicationtheforceisdevelopedasthecylinderstops.Thisiswhenthepressuredifferentialacrossthepistonreachesamaximum.Theonlylossesfromthetheoreticalthrustwillbethosecausedbyfriction.Asageneralrule,makeanallowanceof10%forfriction.Thismaybemoreforverysmallborecylindersandlessforverylargeones.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3DynamicApplicationsThethrustorpulldevelopedindynamicapplicationsisdividedintotwocomponentsOneformovingtheloadTheotherforcreatingabackpressuretohelpexpeltheairontheexhaustingsideofthepistonForalightlyloadedcylinder,mostofthethrustisusedtoexpelthebackpressureAsageneralrule,theestimatedthrustrequirementshouldfallbetween50%and75%ofthetheoreticalthrust《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～3Pistonrodbuckling《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～4PistonrodbucklingSomeapplicationsrequireverylongstrokecylinders.Ifthereisacompressiveaxialloadappliedtothepistonrod,caremustbetakentoensurethatthesystemparametersofrodlength,diameterandloadarewithinthesafetylimitstopreventbuckling.Euler'sFormulaeforElasticInstabilityisexpressedby:Where Fk=EulerLoad(Forcetobuckle)E=ModulusofelasticityI=Secondmomentofarealk=EquivalentfreebucklinglengthFK=2EIl2K《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～4PistonrodbucklingTheequivalentfreebucklinglengthlkusedintheformulaisdeterminedbytheinstallation.Forapinjointedslendercolumn(Eulercase2)thefreebucklinglengthlkisthesameasthelengthlbetweenjoints.Foraslendercolumnwithoneendfreeandtheotherendfixed(Eulercase1)lk=2lKl=2lK

K

31l

12l=l《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～4Pistonrodbuckling1,2&3,awornrodbearingwillallowinitialbucklingasiftherodwerepinjointed.assumelk=l.(Eulercase2)4,5&6,theendoftherodisfreelaterallyassumelk=2l.(Eulercase1)7specialcaselk<2l8specialcaselk<1.5lll51324678l

l

l

l

l

l《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～4PistonrodbucklingGuidetabletomaximumstrokelengthsmm.Safetyfactor"s"=5loadisthethrustdevelopedatthegivenpressure.case4,5,6case716280322100045096011006860390530610106502903904501650021029034080402120050013701580612005007608801095043057066016730320430500CylinderBarcase1,2,3case8805021300450174019906130045096011101011004507208409204105506408063213005001360155061200500750860109204105606401670030042049080802160060016801930615006009201060101100510690800168803805206008100150060013201500611005307108101089038052060016670280390450case4,5,6case7CylinderBarcase1,2,3case8《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～4Speedcontrol《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5SpeedcontrolThemaximumnaturalspeedofacylinderisdeterminedby:thecylindersize,theportssize,inletandexhaustvalveflow,theairpressure,theboreandlengthofthehoses,theloadagainstwhichthecylinderisworking.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5SpeedcontrolFromthenaturalspeeditispossibletoincreaseorreduceit.Normallyasmallervalvereducescylinderspeed.Alargervalvemightincreasecylinderspeed.Alimitingfactorwillbetheapertureinthecylinderportsrestrictedapertureunrestrictedaperture《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5SpeedcontrolOnceavalve,cylinder,pressureandloadareselected,adjustablespeedcontroliseffectedwithflowregulators.SpeedisregulatedbycontrollingtheflowofairtoexhaustThefrontportregulatorcontrolstheoutstrokespeedandtherearportregulatorcontrolstheinstrokespeed.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5Pressure/VelocitygraphThebehaviorofpressureandspeedduringthestrokeofatypicalcushionedcylinderfittedwithflowregulators.00246810Time

Vm/sbar0.20.40.60.81.00movementstartsmovementendsvalveswitched

VelocityP1P2P1pressuredrivingthepistonforwardP2backpressureontheannularsideofthepistonLoadDifferentialtomaintainvelocityagainstloadandfriction《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5FlowregulatorUni-directional,linemountedadjustableflowregulatorFreeflowinonedirectionAdjustablerestrictedflowintheotherdirection《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5BanjoflowregulatorDesignedtofitdirectlyintothecylinderport,soplacingadjustmentattheappropriatecylinderend.Selectthetypetogiveconventionalflowrestrictionoutofthecylinderandfreeflowin.

《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5GuidetocylinderspeedAsanapproximateguide,thegraphshowsthelikelymaximumspeedsthatcanbeachievedwithtypicalcombinationsofvalveCvandcylinderboreagainstpercentageloading.Cv0.4&25diaCv1.0&32diaCv4.0&80diaPistonrodCylinderCv0.4&50diaCv0.35&25diaCv6.0&250dia010Load%30508010002004006008001,000Speedmm/s1,2001,4001,6001,8002,000Rodless《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5IncreasingspeedInsomeapplicationscylinderspeedcanbeincreasedby50%whenusingaquickexhaustvalve.Whenoperated,airfromthefrontofthecylinderexhaustsdirectlythroughthequickexhaustvalve.Builtincushioningwillbelesseffective.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5QuickexhaustvalveAirflowsfromthecontrolvalveintothecylinderpastapoppetlipseal.Whenthecontrolvalveisoperatedthefallingpressurefromthevalveallowsthepoppetsealtosnapopen.Theairinthecylinderrapidlyexhauststhroughthelargeexhaustportandsilencer.

121212《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5ResponsetimesLikelytimeofonecycle.overallresponsetimeofthevalveandcylinder.Tableofguidetimesfordoubleactingcylinders.150-mmstroke.onecycleoutandinstroke5/2solenoid/springvalve.6barpressuresupply.1moftubingbetweenvalveandcylinder.noloadonthepistonrodBoreValveportsCvTimemsecs201/80.3225501/80.4700631/41.05251001/41.01100160?3.5950200?3.5156020017.865032017.81280《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～5Airconsumption《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～6CylinderairconsumptionTherearetwopartstotheairconsumptionofacylinder.Oneisthevolumedisplacedbythepistonmultipliedbytheabsoluteworkingpressure.Twoistheunsweptvolumesuchascavitiesintheendcoverandpiston,thecylinderports,tubingandvalvecavities,allmultipliedbythegaugepressure.Theunsweptpartislikelytobeasmallpercentageandwillvarywithindividualinstallations.Ageneralallowanceofaround5%canbeaddedtocoverthis.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～6CylinderairconsumptionForadoubleactingcylinderthevolumeoffreeairdisplacedbythepistoninonecompletecycle

Pushstroke

PullstrokeWhereD=cylinderboremmd=roddiametermmV=volumeindm3freeairS=strokemmPs=supplygaugepressurebarPa=atmosphericpressure(assumedtobe1bar)

V=.S.(Ps+Pa).10-64D2V=.S.(Ps+Pa).10-64(D2-d2)《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～6CylinderairconsumptionToestimatethetotalaverageairconsumptionofapneumaticsystemmakeacalculationforeachcylinderinthesystem.Addthesetogetherandadd5%.Itisimportanttounderstandthattheinstantaneousflowrequirementforasystemwillbehigherthantheaverageandinsomecasesverymuchhigher.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～6TableofconsumptionTakeeachfigureandmultiplybythestrokeinmm.Forpressuresotherthan6barmultiplybytheabsolutepressuredividedbyseven.strokeat6barBoremmRodmmPushstrokeconsumptiondm3/mmofstrokeat6barPullstrokeconsumptiondm3/mmofCombinedconsumptiondm3/mmofstroke/cycle1040.000540.000460.001001260.000790.000650.001441660.001410.001210.002622080.002200.001850.0040525100.003440.002890.0063332120.005630.004840.0104740160.008800.007390.0161950200.013740.011550.0252963200.021820.019620.0414480250.035190.031750.06694100250.054980.051540.10652125320.08590.080270.16617160400.140740.131950.27269200400.219910.211120.43103250500.343610.329870.67348《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～6Seals《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7SealsIdentificationofsealsinadoubleactingadjustablecushionedcylinder

1234561Cushionscrewseal2Cushionseal4Pistonseal5Barrelseal6Pistonrod/wiperseal3Wearring《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7‘O'RingpistonsealsAn‘O'-ringpistonsealisaloosefitinthegroove,withtheouterdiameterjustincontactwiththecylinderbore.Whenpressureisappliedthe‘O'-ringispushedsidewaysandoutwardstosealtheclearancebetweentheouterdiameterofthepistonandthecylinderwall.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7CupsealsUsedonmediumandlargeborecylinders.Sealinonedirectiononly.OneforsingleactingTwofordoubleactingLowradialexertiontoreducethestaticbreakoutfrictionHighcompliance《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7ZRingsUsedforpistonsealsonsmallerborecylindersSealsinbothdirectionsTakeuplessspaceZshapeactsasalightradialspringprovidinglowradialexertionandhighcompliance.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7‘O'RingbarrelsealsThesearestaticsealsandwillbeatightfitintheirgroovelocationsButtjointsealfortierodconstruction.Screwedbarrelandendcover《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7CushionsealsThesesealsperformadualroleofsealandnonreturnvalve.Sealingontheinsidediameterandonefacewhencushioning.Airflowsfreelyaroundtheoutsidediameterandgroovesintheotherfacewhenthepistonisdrivenout.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7PistonrodsealsOnepiecesealservesthedualroleofpressuresealandwiperseal.Outerbodyofthesealisapressuretightfitwithinthebearinghousing.Cleaningactionremovesabrasiveparticlesthatcansettleontherodwhenoutstroked.Specialsealforharshenvironments《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7PistonrodbellowsAlternativetospecialwiperseals,alsoreferredtoasgaiters.Specifyasoriginalequipment,asthecylinderrequiresaslightlylongerthanstandardpistonrod.Idealsolutionwheretheoutstrokedpistonrodislikelytobescratchedorabradedbyfallingdebris.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7ExtremeoperatingtemperaturesStandardsealsaregenerallyrecommendedforcontinuousrunningintherange+2oCto+80oC.Highertemperatureswillsoftenthesealssothattheywearquicklyandproducemorefriction.Lowertemperatureswillhardenthesealswhichmakethembrittleandliabletosplittingandcracking.Forhightemperatureapplicationswithcontinuousrunningatanambientupto150oC,cylindersfittedwith"Viton"sealsshouldbespecified.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7WearringAwearringisanopenbandfittedaroundthepiston.Itismadefromahardplasticmaterial.Intheeventofahighsideload,itbecomesabearingthatpreventsexcessivedistortionoftheseals.Protectsagainstscoringofthebarrelfromthepiston.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～7Cushiondesign《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～8CushiondesignCushioningprotectsacylinderandloadbyabsorbingtheenergyattheendofstroke.Thisresultsinprogressivedecelerationandgentlecontactbetweenthepistonandendcover.Fixedcushioningwithshockabsorbingpadsisappliedtosmalllightdutycylinderswhichhavelowmassinthepiston,rodandload.Largercylindershaveadjustablepneumaticcushionswhichfunctionoverthefinal2cmofstroke.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～8FixedcushiondesignShockabsorbentdiscssetintotheendcoverscushiontheimpactofthepiston《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～8Adjustablecushiondesign《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9AdjustablecushiondesignThepistonismovingtotheleftatspeed.Airisventingthroughthecentreoftheseal.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9AdjustablecushiondesignThecushionsealispushedtotheleftandsealsagainstit’slefthandedgeandinsidediameter.Aircanonlyescapepastthecushionscrew.Thepressurebuildsupandcushionsthepiston.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9AdjustablecushiondesignThescrewissettobringthepiston,rodandloadtoagentlehaltagainsttheendcover.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9AdjustablecushiondesignAvalvehasbeenoperatedtopowerthepistonout.Thecushionsealispushedtotheright.Groovesintherighthandedgeandoutsidediameterbypassthescrew.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9AdjustablecushiondesignThepistonisstartedintheotherdirectionun-restrictedbythecushionscrewsetting.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～9Shockabsorbers《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10ShockabsorbersForsmoothdecelerationofveryhighmassandvelocity.Supplementortakeoveracylinder'sbuiltincushioning.NonadjustableselfcompensatingunitsAdjustableunitsintwosizes.Selfcompensating0.9to10Kg2.3to25Kg9to136Kg105to1130KgAdjustable5to450Kg10to810Kg《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10SelfcompensatingunitsTheprincipleofoperationisprogressiveflowrestriction.Thepistonispushedineasilyatfirst,oilisdisplacedthroughalargenumberofgraduatedmeteringorifices.Asthestrokeprogressesfewerandfewermeteringorificesareavailable.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10AdjustableunitsInternalaccumulatorcontainingclosedcellelastomerfoamasfluiddisplacementreservoir.Orificesizescanberegulatedbyoperatinganadjustingring.Thisallowsprecisedecelerationtobeachievedoverawiderangeofmassandvelocitycharacteristics.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10ShockabsorbersCalculatetheequivalentmassusingthisformulame=2W3v2Where W3=totalenergyW1+W2(Nm) me=equivalentmass(kg) W1=kineticenergy=?m.v2(Nm) W2=energyoftheforce=F.s(Nm) m=mass(Kg) v=velocity(m/s) F=propellingforce(N) s=strokeofshockabsorber(m)《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10ExampleMassof10kg,force100N,willcontacttheshockabsorberwithavelocityof1m/s.Thestrokeoftheselfadjustingunitisanominal0.025m.

W1=10×12÷2=5NmW2=100×0.025=2.5NmW3=5+2.5=7.5Nmme=2×7.5÷12=15kgs=0.025mv=1m/sF=100N《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～10Standards《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～11StandardsISO6431and6432standardisetheinstallationdimensionsofspecifiedpneumaticcylindersandtheirfittedmountings.Mountingsfromonemanufacturerhowevermaynotfitwiththecylinderfromanother.VDMA24562isarefinementoftheabovestandardsfurtherdefiningdimensions,particularlytierodcentresandtheattachmentofmountingstothem.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～11StandardsISO6009relatestothedimensioncodesusedinmanufacturersdimensiondatasheetsThereareadditionalmountingsbeyondthescopeofthisstandard.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～11NonstandarddimensionsTherearemanyrangesofcylinderdesignsnotboundbythedimensionalrestrictionsofastandard.Thesecylindersincorporatethelatestinnovationsinmanufacturingtechniquetoprovideneatandcompactdesignsresultinginsmalleroverallsizes.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～11Typesofconstruction《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～12TypesofconstructionThefactorscontrollingthetypeofconstructionofacylinderareSize,duty,cost,style,standardsandcompatibilityofmaterialsSealedforlifetypesLowcost,lightduty,smalltomediumborecylinders.Thepistonispre-greasedforlifeonassemblyandcanbeoperatedwithnonlubricatedorlubricatedair.Types:microcylinders,roundline,smallborecompactServiceabletypesItiseconomicalfortheusertoextendtheirlifebyreplacementofwornsealsandre-greasing.Alsothereplacementofaccidentallydamagedpartsmaybepossible.Types:smallboreISO,largeborecompact,ISO/VDMArange,heavyduty.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～12MicrocylindersVerysmallbore2.5mmto6mmdiameter,mainlysingleactingsprungtotheinstroke.ForuseinlightdutyminiatureassemblyandmanufacturingForoperationinthepressurerange2.5barto7bar.Sealedforlife《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～12RoundlinecylindersLowcost,lightduty,smalltomediumborecylindersintherange8mmto63mmdiameter.Thecylindersaresealedforlifebyrollingthebarrelendsandendcoversdowntomakeapressuretightseal.Foroperationinthepressurerange1to10bar.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～12Compactcylinders12-40mmShortoveralldimensionthatisapproximatelyonethirdofthezerostrokelengthofacomparableISOdesign.AmagneticpistonisstandardonthesingleactingversionsNon-magneticandmagnetictypesinthedoubleactingpressurerangefrom1barto10bar.Sealedforlife.《氣動(dòng)技術(shù)》雙語(yǔ)電子教案吳洪明Chapter4～12ServiceableLightandMediumDutyThesedesignscanbedismantledandreassembledbytheuser.Itcanbeeconomicaltoservicethesecylindersandextendtheirlifebyreplaci