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1、NACHI-FUJIKOSH CORP. TOKYO, JAPAN JAN. 2010 forfor Mini-ExcavatorMini-ExcavatorMini-ExcavatorMini-ExcavatorBoomBoomArmArmBucketBucketDozerDozerCrawlerCrawlerWheelMotorWheelMotorSwingSwingMotorMotorPumpPumpEngineEngine ValveValveiftift BirthofExcavatorBirthofExcavatornExcavatorwasborninearly1950sinNo
2、rthItaly.In1962itwasintroducedtoJapanthroughatechnicalagreementwithYumbo. HydraulicCircuitinearlydaysHydraulicCircuitinearlydays Pressure:90barwithgearpumpPressure:90barwithgearpump ControlValvewithOpenCenterControlValvewithOpenCenter ParallelCircuitParallelCircuit LowperformanceincomplexoperationLo
3、wperformanceincomplexoperationFig.Fig. HydrauliccircuitHydrauliccircuitBoomBoomArmArmBucketBucketTravel(L)Travel(L)Travel(R)Travel(R)SwingSwingEngineEngineGearPumpGearPump90bar90barTwopumpsystemTwopumpsystemFortheactuatorswithfrequentandcomplexoperationFortheactuatorswithfrequentandcomplexoperationF
4、ig.Fig. 2pumpand2valve2pumpand2valve systemsystemBoom1Boom1Arm1Arm1SwingSwingTravel(L)Travel(L)Travel(R)Travel(R)BucketBucketBoom2Boom2Arm2Arm2ThreepumpsystemThreepumpsystemIsolatedpumpforSwingoperationIsolatedpumpforSwingoperationparallel&tandemcircuitparallel&tandemcircuitFig.Fig. 3pumpCircuit3pum
5、pCircuit systemsystemSwingSwingBoom2Boom2Arm1Arm1Travel(L)Travel(L)Travel(R)Travel(R)Boom1Boom1Arm2Arm2BucketBucket ChansinghighperformanceChansinghighperformanceGoodcombinationwithGoodcombinationwithparallel&tandemcircuitparallel&tandemcircuit BestselectionforchokesizeBestselectionforchokesizeMergi
6、ngvalveachieveMergingvalveachieve thethebetterperformanceevenbetterperformanceeven onaonacomplexoperationcomplexoperationBoom2Boom2Arm1Arm1TravelLTravelLTravelRTravelRServiceServiceBoom1Boom1BucketBucketArm2Arm2PumpcontrolSPumpcontrolSystemystem&Energysaving&EnergysavingPickupthepressuredropinsteado
7、faPickupthepressuredropinsteadofableedoffflowrateatthemostdownstreambleedoffflowrateatthemostdownstreamontheopencenterbypasslinewithchokeontheopencenterbypasslinewithchokeresistanceresistanceFeedbackthepressuredroptoFeedbackthepressuredroptopumpinordertogettheconstantpumpinordertogettheconstantbleed
8、offflowratebleedoffflowrateWithoutwastefulflowWithoutwastefulflowSaveEnergySaveEnergy(1)NegativeControl(1)NegativeControlFig.NegativeControlFig.NegativeControlPumpcontrolPumpcontrolSystemSystem&EnergySaving&EnergySavingPickupthepilotpressurePickupthepilotpressureatpilotvalveatpilotvalveEstimateanece
9、ssaryflowrateinorderEstimateanecessaryflowrateinordertocontrolthepumptocontrolthepumpWithoutwastefuloutletWithoutwastefuloutlet SavingEnergySavingEnergy(2)PositiveControl(2)PositiveControlFig.PositiveControlFig.PositiveControlPumpcontrolSystem&PumpcontrolSystem& SavingEnergySavingEnergyFromGearPumpF
10、romGearPumptoPistonPump(constanttoPistonPump(constantHPcontrol)HPcontrol) Morepowerful&Morepowerful&higherspeedhigherspeed(3)Adoptionthevariablepistonpumpfor(3)Adoptionthevariablepistonpumpfor miniexcavatorminiexcavatorFig.Fig. AdvantageonvariableAdvantageonvariablepistonpumppistonpumpC CA AB BConst
11、antHorseConstantHorsePowerCurvePowerCurvePressure(Power)Pressure(Power)FlowRate(Speed)FlowRate(Speed)Basedonthefixedpump(RangeA)Basedonthefixedpump(RangeA)IncaseofvariablepistonpumpIncaseofvariablepistonpump*PressurerangereachestoRangeB*PressurerangereachestoRangeB*FlowRatealsoreachestoRangeC*FlowRa
12、tealsoreachestoRangeCInotherwords,ifyouwantBorC,Inotherwords,ifyouwantBorC,youneedmuchbiggerengineyouneedmuchbiggerenginePartiallyreturnflowPartiallyreturnflowgoesbacktoheadgoesbacktoheadsideofarmcylindersideofarmcylinderMuchquickerspeedMuchquickerspeedInventiononacircuitInventiononacircuit(1)Regene
13、ratedcircuitforArm(1)RegeneratedcircuitforArmArmArmBucketBucketGravityGravityBoomBoomArmCylinderArmCylinderPulledbygravityPulledbygravityFig.Fig. RegeneratedRegenerated circuitcircuit forfor ArmArmReturntoTankReturntoTankSupplyfromPumpSupplyfromPumpInventiononacircuitInventiononacircuitOnoperationof
14、travelmotor,Onoperationoftravelmotor,Outletflowfrom3rdpumparesuppliedtotheotheractuatorOutletflowfrom3rdpumparesuppliedtotheotheractuatorAchievethemuchhigherperformanceoncomplexoperationAchievethemuchhigherperformanceoncomplexoperation(2)StraightTraveling(2)StraightTravelingFig.ExamplecircuitFig.Exa
15、mplecircuitPreventionforfallingPreventionforfallingBucketBucketBoomBoomTravelRTravelRTravelLTravelLPriorityCircuitPriorityCircuitBoom2Boom2ArmArmServiceServiceShiftShiftDozerDozerSwingSwingSignalLineSignalLineSecondParallellineSecondParallellineStraightTravelValveStraightTravelValve Inventiononacirc
16、uitInventiononacircuit(3)PrioritymergingcircuitforArm(3)PrioritymergingcircuitforArmBoomOperationOnlyBoomOperationOnlyArmoperationonlyArmoperationonlyComplexboom&armComplexboom&armConventionalConventionalViPPSViPPS NeedsondevelopmentNeedsondevelopment(1)Betterperformanceonoperating(1)Betterperforman
17、ceonoperating InparticulartogettheisolatedperformanceoneachInparticulartogettheisolatedperformanceoneachsectionsection(2)SavingEnergyandmuchhigherspeed(2)SavingEnergyandmuchhigherspeed Withvariablepistonpump&inventedcircuit,Withvariablepistonpump&inventedcircuit,achievelessenergyandhigherspeedachiev
18、elessenergyandhigherspeed(3)Muchsafersystem(3)Muchsafersystem VariousinventionforthesafetyVariousinventionforthesafetyAtneutralpositionoutletflowfromPumpisunloaded.AtneutralpositionoutletflowfromPumpisunloaded.Speedforactuatorisinproportiontotheangleoflever.Speedforactuatorisinproportiontotheangleof
19、lever.OpenCenterSystemOpenCenterSystem ConventionalSystemConventionalSystemSpeedonactuatordependsonthebleedingflowrate.Speedonactuatordependsonthebleedingflowrate.InotherwordsdependsonLoadingPressure.InotherwordsdependsonLoadingPressure.Inparticularcomplexoperationbringsdifferentgain.Inparticularcom
20、plexoperationbringsdifferentgain.DisadvantageonOpencenterDisadvantageonOpencenterConventionalLSsystemConventionalLSsystemTokeepTokeep constant,PressureCompensatorconstant,PressureCompensatorValveisrequired.Valveisrequired. Fig.ConventionalLSsystemFig.ConventionalLSsystemConventionalLSsystemConventio
21、nalLSsystemSuppliedflowisinproportiontothespoolstroke(OpenArea).ConstantSuppliedflowisinproportiontothespoolstroke(OpenArea).ConstantFlowatanyLoad.FlowatanyLoad.Fig.Fig. CharacteristicsonLSCharacteristicsonLS ：FlowCoefficientFlowCoefficient ：OpenAreaOpenArea ：GravityAccelerationGravityAcceleration ：
22、 ：DensityofoilDensityofoil：DifferentialpressurebetweeninandoutDifferentialpressurebetweeninandoutofSpoolofSpoolConventionalLSsystemConventionalLSsystemNoinfluencefrompressurefluctuationofloadNoinfluencefrompressurefluctuationofloadDisadvantageofconventionalLSDisadvantageofconventionalLSAtsaturatedco
23、nditionPriorityisforLowload,AtsaturatedconditionPriorityisforLowload,ZerosupplytotheactuatoratHighLoadZerosupplytotheactuatoratHighLoadFig.LSpumpFig.LSpumpFig.DisadvantageonConventionalLSFig.DisadvantageonConventionalLSAtSufficientFlowtoAtSufficientFlowtoActuatorActuatorInsufficientFlowtoInsufficien
24、tFlowtoActuatorsActuatorsNACHILoadsensingsystemNACHILoadsensingsystemPhoto:ControlValve&PistonPumpPhoto:ControlValve&PistonPump （ （DPK-T04DPK-T04）（PVK-1BPVK-1B） ） NACHILoadsensingsystemNACHILoadsensingsystemSecondarypressurefeedbacksystemwithreducingvalveSecondarypressurefeedbacksystemwithreducingva
25、lveLSValveLSValve(DPK-T04)LSPumpLSPump（ （PVK-1B,2B)PVK-1B,2B) Fig.NACHILSFig.NACHILSSystemSystemStructureandoperationalprincipleofpressureStructureandoperationalprincipleofpressurecompensatorcompensator： PressureattheupperstreamPressureattheupperstream： LoadedPressureLoadedPressure：（）：（）： MaximumLoa
26、dedPressureMaximumLoadedPressureAntisaturationfunctionAntisaturationfunctionSamesecondarypressureissuppliedtoeverycompensatorSamesecondarypressureissuppliedtoeverycompensatorFlowratetoeachactuatorisdividedwitharatioFlowratetoeachactuatorisdividedwitharatioFig.AntiSaturationFunctionFig.AntiSaturation
27、FunctionSufficientFlowSufficientFlowInsufficientFlowInsufficientFlowHuntingonswingmotorHuntingonswingmotorunderLSsystemunderLSsystemOnActuatorwithinertia(SwingOnActuatorwithinertia(SwingMotor),fluctuationofMotor),fluctuationofloadpressureisalwaysaheadofloadpressureisalwaysaheadofoutputspeed.outputsp
28、eed.InletflowfluctuatesinplussideInletflowfluctuatesinplussideandminussideagainstrequiredandminussideagainstrequiredflow.Consequentlymotorworksflow.Consequentlymotorworkswithhunting.withhunting.LoadPressureLoadPressureOutputSpeedonSwingOutputSpeedonSwingmotormotorTimeTimeTimeTimeRequiredRequiredFlow
29、FlowOutputSpeedOutputSpeedPressurecompensationvalvePressurecompensationvalveaccordingtoloadedpressureaccordingtoloadedpressureFig.Fig. StructureStructureIncaseofIncaseof、 :DifferentialPressure:DifferentialPressure（）（）OperationalPrincipleOperationalPrinciple：PressureatupperstreamPressureatupperstream
30、： LoadedPressureLoadedPressure：SecondaryPressurethroughSecondaryPressurethrough regulatorvalveregulatorvalve（）（）：MaximumloadedpressureMaximumloadedpressure： AreaRatioAreaRatioCharacteristicLoad-FlowCharacteristicLoad-FlowLoadedPressureLoadedPressureFlowRateFlowRateFlowRateFlowRateNormalpressurecompe
31、nsationNormalpressurecompensationforgeneralactuatorforgeneralactuatorPressurecompensationaccordingPressurecompensationaccordingtoloadedpressuretoloadedpressureOptionalOptionalsettingsettingLoadedPressure(MPa)LoadedPressure(MPa) CooperativesystemwithenginespeedCooperativesystemwithenginespeedTargetPi
32、scooperativeTargetPiscooperativewithenginespeedwithenginespeedMuchfinercontrolwithMuchfinercontrolwithgentlegainbetweengentlegainbetweenstroke&flowrate.stroke&flowrate.Fig.LoadSensingFig.LoadSensingFig.Fig. CooperativeSystemwithenginespeedCooperativeSystemwithenginespeedFig.Fig. OpenCenterSystemOpen
33、CenterSystemCooperativesystemwithenginespeedCooperativesystemwithenginespeedAnOrificeisinstalledinoutputlineofpilotpump.AnOrificeisinstalledinoutputlineofpilotpump.PicksupPofbeforeandaftertheorifice,andchangestargetLSP.PicksupPofbeforeandaftertheorifice,andchangestargetLSP. FeatureFeatureStabilizeds
34、ystemwithouthuntingStabilizedsystemwithouthuntingAntiSaturationFunctionAntiSaturationFunction（ （PAT.PEND.PAT.PEND.） ）QuickerresponsetimeQuickerresponsetimeBetterperformanceonstraighttravelingBetterperformanceonstraighttravelingUnnecessaryanexclusivepumpforSwingUnnecessaryanexclusivepumpforSwing（ （PA
35、T.PEND.PAT.PEND.） ）BettereveninalowtemperatureconditionBettereveninalowtemperaturecondition（ （PAT.PEND.PAT.PEND.） ）ControlSystembasedonenginespeedControlSystembasedonenginespeed（ （PAT.PEND.PAT.PEND.） ）ExcellentperformanceonfinecontrolExcellentperformanceonfinecontrol（ （PAT.PEND.PAT.PEND.） ）Lowerpres
36、suredropLowerpressuredropVariousoptionalaccessoriesVariousoptionalaccessoriesOverLoadReliefvalveOverLoadReliefvalveVacuumCheckValveVacuumCheckValveBoomLockValve(AntiDriftValve)BoomLockValve(AntiDriftValve) （）（）（）（）（）（）（）（） SpecificationSpecification ExternalAppearance(Ex.)ExternalAppearance(Ex.) DPK
37、-T04DPK-T04 Pumpdimension(Example)Pumpdimension(Example) PVK-2BPVK-2BOUTOUTOUTOUTOilsupplyOilsupplyInputportInputportInputportInputportININPLSportPLSportViewfromAViewfromAViewfromBViewfromBSystemcomparisonSystemcomparison ExampleExample ofof applicationapplicationZero tail typeUrban typeHitachiConst
38、ructionmachineryHitachiConstructionmachinery OtherLSsystemwithOtherLSsystemwithaantisaturationfunctionntisaturationfunctionBeforeorificetypeBeforeorificetype(Linde:1984)(Linde:1984)：PumpdeliveryPressurePumpdeliveryPressure： PressureattheupperstreamPressureattheupperstream： LoadedPressureLoadedPressu
39、re： MaximumLoadedPressureMaximumLoadedPressure +PL+PL ININmaxmax-P-P maxmax OtherLSsystemwithOtherLSsystemwithaantisaturationfunctionntisaturationfunctionAfterorificetypeAfterorificetype(Linde:1984)(Linde:1984)：PumpdeliveryPressurePumpdeliveryPressure outout： ： PressureatthedownstreamPressureatthedo
40、wnstream： LoadedPressureLoadedPressure： MaximumLoadedPressureMaximumLoadedPressureW:Springforce(50d,51d)W:Springforce(50d,51d) outout Lmax+WLmax+W W=0(weakforce)W=0(weakforce) outout LmaxLmaxoutout-P-P maxmaxPoutPoutPoutPout OtherLSsystemwithOtherLSsystemwithaantisaturationfunctionntisaturationfunct
41、ionBeforeorificetypeBeforeorificetype(Komatsu(Komatsu： ：1991)1991)：PumpdeliveryPressurePumpdeliveryPressure： PressureattheupperstreamPressureattheupperstream： LoadedPressureLoadedPressure： MaximumLoadedPressureMaximumLoadedPressure +PL+PLININmaxmax-P-P maxmax OtherLSsystemwithOtherLSsystemwithaantis
42、aturationfunctionntisaturationfunctionMeterouttypeMeterouttype(Toshibamachine(Toshibamachine： ：1990)1990)：PumpdeliveryPressurePumpdeliveryPressure： LoadedPressureLoadedPressure： MaximumLoadedPressureMaximumLoadedPressureW:Springforce(60d,61d)W:Springforce(60d,61d) L+WL+W LmaxLmax W=0(weakforce)W=0(weakforce) LL LmaxLmaxL L-P-P maxmaxAPPLICATIONS
