I.Analysisandtroubleshootingofcommonfaultsinhydraulicpumps

a,failurephenomenon:nooil,insufficientinfusion,pressuredoesnotgo

Faultanalysis:1.Themotorisnotturningright,2.Thesuctionpipeorfilterisclogged,3.Theaxialclearanceorradialclearanceistoolarge,4.Theconnectionisleaking,mixedwithair,5.Themediumviscosityistoohighorthetemperatureriseistoohigh..

Remedy:1.Checkthemotorsteering,2.Unblockthepipeline,cleanthefilter,replacethenewworkingmedium,3.Checkandreplacetherelevantparts,4.Tightenthescrewsateachjointtoavoidleakage,andpreventairfromentering,5.CorrectUseworkingmediumtocontroltemperaturerise.

b, failure phenomenon: noise, severe pressure fluctuations

Fault analysis: 1. The suction pipe and filter are blocked or the filter capacity is small. 2. The air suction pipe seal leaks or there is air bubble in the medium. 3. The pump is not concentric with the coupling, 4. The oil level is low, 5. Oil Low temperature or high viscosity, 6. Pump bearing damage.

Remedy: 1. Clean the filter to make the suction pipe unobstructed, and select the filter correctly. 2. Add some oil to the joint or seal. If the noise is reduced, tighten the joint or replace the seal; the return pipe should be in the oil. Below, there must be a certain distance from the oil suction pipe, 3. Adjust the concentricity, 4. Refueling liquid, 5. Heat the oil to the appropriate temperature, 6. Check (hand touch) the temperature rise of the pump bearing part.

c,failurephenomenon:pumpshaftoilsealleakage

Faultanalysis:Theliquidleakageoftheoilleakagepipelineistoolarge,sothatthepressureinsidethepumpbodyrisestoexceedtheallowablepressurevalueoftheoilseal.

Remedy:Checkifthedrainportonthepumpbodyoftheplungerpumpisconnectedtothetankdirectlywithaseparateoilpipe.Ifitisfoundthattheleakageoilpipesofseveralplungerpumpsareconnectedinparalleltoacommonpipeofthesamediameterandthenconnectedtothefueltank,orthedrainpipeofthepistonpumpisconnectedtothereturnpipe,itshouldbecorrected.Itisbesttoconnectapressuregaugetothepumpleakporttocheckthepressureinsidethepump,whichshouldbelessthan0.08Mpa.

Second,thefailureanalysisandtroubleshootingofthereliefvalve

a,failurephenomenon:pressurefluctuations

Faultanalysis:1.Thespringisbentortoosoft,2.Theconevalveisinpoorcontactwiththevalveseat,3.Thesteelballandthevalveseatareinpoorcontact,4.Theslidingvalveisdeformedorpulled,5.Theoilisnotclean,andthedampingholeisblocked.

Remedy:1.Replacethespring,2.Iftheconevalveisnew,removetheadjustingnutandpushtheguiderodafewtimestomakeitcontactwell;orreplacetheconevalve,3.Checktheroundnessofthesteelball,replacethesteelball,grindingthevalveseat,4.replacingorrepairingtheslidevalve,5.dredgingtheorificeandreplacingthecleaningfluid.

b,failurephenomenon:adjustmentisinvalid

Faultanalysis:1.Thespringisbrokenormissing,2.Thedampingholeisblocked,3.Theslidingvalveisstuck,4.Theinletandoutletportsarereversed,and5.Theconevalveismissing.

Remedy:1.Check,replaceorreplenishthespring,2.Unblocktheorifice,3.Remove,inspect,trim,4.Checkthedirectionoftheoilsource,5.Checkandrefill.

c,failurephenomenon:seriousleakage

Faultanalysis:1.Thecontactbetweentheconevalveorthesteelballandthevalveseatispoor,2.Theclearancebetweentheslidevalveandthevalvebodyistoolarge,3.Thepipejointisnottightened,4.Thesealisbroken.

Remedy:1.Replacethenewconevalveorsteelballwhentheconevalveorsteelballisworn.2.Checkthegapbetweenthevalvecoreandthevalvebody.3.Tightenthecouplingscrew.4.Checkandreplacetheseal.

d,faultphenomenon:noiseandvibration

Faultanalysis:1.Thenutisloose,2.Thespringisdeformed,itisnotrestored,3.Thespoolvalveistootight,4.Themainspoolvalveisnotworkingwell,5.Theconevalveisworn,6.Thereisairintheoilpassage,7.Theflowrateexceedstheallowablevalue,8.Resonancewithothervalves.

Remedy:1.Tightenthenut,2.Checkandreplacethespring,3.Repairtheslidevalvetomakeitflexible,4.Checktheconcentricityoftheslidevalveandthehousing,5.Changetheconevalve.

Third,thefailureanalysisandtroubleshootingofthepressurereducingvalve

a.Faultphenomenon:unstablepressurefluctuation

Faultanalysis:1.Airismixedintotheoil.2.Theorificeissometimesblocked.3.Theroundnessofthespoolandthevalvebodyexceedsthespecifiedvalue,sothatthevalveisstuck.4.Thespringisdeformedorstuckinthespool.Thevalveisdifficulttomoveorthespringistoosoft.5.Thesteelballisnotround,thesteelballisnotwellmatchedwiththevalveseatortheconevalveisnotinstalledcorrectly.

Remedy:1.Eliminateairinoil,2.Cleanthedampinghole,3.Repairthevalveholeandslidevalve,4.Replacethespring,5.Replacethesteelballordisassembletheconevalvetoadjust.

b,failurephenomenon:secondarypressureriseisnothigh

Faultanalysis:1,externalleakage,2,poorcontactbetweentheconevalveandthevalveseat.

Remedy:1.Replacetheseals,tightenthescrews,andensurethetorqueiseven,2,repairorreplace.

c,failurephenomenon:nodecompression

Faultanalysis:1.Thedrainportisunreachable;thedrainpipeisconnectedtotheoilreturnpipeandhastheoilreturnpressure.2.Themainspoolisstuckinthefullyopenposition.

Remedy:1.Thedrainpipemustbeseparatedfromtheoilreturnpipeandreturnedtothefueltankseparately.2.Repairandreplacethepartsandchecktheoilquality.

Fourth,thefailureanalysisandtroubleshootingmethodofthrottlespeedcontrolvalve

a,failurephenomenon:throttlingeffectfailureandspeedregulationrangeisnotlarge

Faultanalysis:1.Thegapbetweenthethrottlevalveandtheholeistoolarge,thereisleakageandinternalleakageofthesystem,2.Theorificeisblockedorthespoolisstuck.

Remedy:1.Checkthedamageofthepartsintheleakingpart,repairandupdateit,payattentiontotheoilsealofthejoint.

2.Disassemblethecleaningandreplacethenewoiltomakethespoolmoveflexibly.

b,failurephenomenon:themovementspeedisunstable,suchasgraduallyslowingdown,suddenlyincreasingandbeating

Faultanalysis:1.Theimpuritiesintheoiladheretotheedgeofthethrottle,thecrosssectionoftheoilisreduced,sothatthespeedissloweddown,2.Theperformanceofthethrottlevalveispoor,andtheadjustmentpositionischangedduetovibrationduringlowspeedmovement.Internalandexternalleakageofthethrottlevalve.4.Inthesimplifiedthrottlevalve,thespeedchangessuddenlyduetochangesinthesystemload.5.Theoiltemperaturerises,theviscosityoftheoildecreases,andthespeedisgraduallyincreased.6.DampingThedeviceisclogged,thereisairinthesystem,andpressurechangesandjittersoccur.

Remedy:1.Disassembleandcleantherelevantparts,replacethenewoil,andkeeptheoilclean.2.Increasethethrottleinterlockingdevice.3.Checktheaccuracyandmatchingclearanceoftheparts.Repairorreplacethepartsthatareoutoftolerance.Itisnecessarytostrictlyclose,4.Checkthefunctionofthesystempressureanddecompressiondeviceandthecontrolofthereliefvalve.5.Afterthehydraulicsystemisstable,adjustthethrottlevalveorincreasetheoiltemperatureandheatdissipationdevice.6.Cleantheparts.Anexhaustvalveisaddedtothesystemtokeeptheoilclean.

V.Faultanalysisandeliminationofthereversingvalve

a,faultphenomenon:thespooldoesnotreverse

Faultanalysis:1,theslidevalveisstuck,2,thevalvebodyisdeformed,3,thecenteringspringwiththeintermediatepositionisbroken,4,theoperatingpressureisnotenough,5,theelectromagnetcoilisburntoutortheelectromagnetisinsufficientlythrust,6,theelectriccircuitFailure,7,thehydrauliccontrolvalvetocontroltheoilcircuitisoil-freeorblocked

Remedy:1.Disassembleandcleanthedirtanddeburr.2.Adjustthevalvebodytoinstallthescrewtomakethepressuretight,evenlyorrepairthevalvehole.3.Replacethespring.4.Theoperatingpressuremustbegreaterthan0.35Mpa.5.Check.,repair,replacement,6,eliminatethefault,7,checkthereasonsandeliminate.

b.Faultphenomenon:thereisasoundwhenthedirectionalvalvecontrolledbytheelectromagnetacts

Faultanalysis:1.Theslidevalveisstuckorthefrictionistoolarge.2.Theelectromagnetcannotbepressedtothebottom.3.Thecontactsurfaceoftheelectromagnetcoreisnotflatorthecontactispoor.

Remedy:1.Repairoradjusttheslidevalve,2.Correcttheheightoftheelectromagnet,3.Eliminatedirtandcorrecttheelectromagnetcore.

6.Faultanalysisandeliminationofhydrauliccontrolcheckvalve

a,failurephenomenon:oildoesnotflowbackwards

Faultanalysis:1.Thecontrolpressureistoolow.2.Theoilleakageofthecontroloilpipejointisserious.3.Thecheckvalveisstuck.

Remedy:1.Increasethecontrolpressuretoachievetherequiredvalue.2.Fastenthejointtoeliminateoilleakage.3.Clean.

b,failurephenomenon:nosealinginthereversedirection,thereisleakage

Faultanalysis:1.Thecheckvalveisstuckinthefullyopenposition.2.Thecontactsurfaceofthecheckvalveisnotuniformwiththeconesurfaceofthevalveseat.

Remedy:1,repair,cleaning,2,repairorreplacement.

Seven,theoiltemperatureistoohighfailureanalysisandtroubleshooting

a,faultphenomenon:whenthesystemdoesnotneedpressureoil,andtheoilstilloverflowstothetankunderthesetpressureofthereliefvalve

Faultanalysis:Pooroperationoftheunloadingcircuit.

Remedy:Checktheoperationoftheelectricalcircuit,solenoidvalve,pilotcircuitandunloadingvalve.

b,failurephenomenon:theselectionofhydrauliccomponentsisunreasonable

Faultanalysis:1,thevalvesizeistoosmall,theenergylossistoolarge,2,whenthepumpisselected,thepumpflowistoolarge.

Exclusionmethod:1.Accordingtotheworkingpressureofthesystemandthemaximumflowratethroughthevalve,2.Selectthepumpreasonably.

c,failurephenomenon:insufficientcooling

Faultanalysis:1.Thecoolingwatersupplyisoutoforderorthefanisoutoforder.2.Thereisprecipitationinthecoolingwaterpipeline.

Remedy:1,eliminatethefault,2,eliminateprecipitation.

d,failurephenomenon:insufficientheatdissipation

Faultanalysis:Theheatdissipationareaofthefueltankisinsufficient.

Remedy:Refitthecoolingsystemorincreasethetankcapacityandheatdissipationarea.

e,failurephenomenon:hydraulicpumpoverheating

Faultanalysis:1.Powerlossduetowear,2.Workwithoilwithtoolowortoohighviscosity.

Remedy:1,repairorreplace,2,selecttheoilsuitablefortheviscosityofthesystem.

f,failurephenomenon:oilcirculationistoofast

Faultanalysis:Theliquidlevelinthetankistoolow.

Remedy:Addtheoiltotherecommendedlocation.

g,failurephenomenon:excessiveresistanceofoil

Failureanalysis:Theinsidediameterofthepipeisnotcompatiblewiththerequiredflowrateorbecausetheinnerdiameterofthevalveisnotlargeenough.

Remedy:Installpipesandvalvesofappropriatesizeorreducepower.

Eight,hydrauliccylindercommonfaultanalysisandtroubleshooting

a,failurephenomenon:crawling

Faultanalysis:1,airintrusion,2,hydrauliccylinderendcapsealringistootightortooloose,3,pistonrodandpistonarenotthesame,4,thepistonrodfulllengthorpartialbending,5,hydrauliccylinderinstallationpositionOffset,6,thehydrauliccylinderboreisnotlinear(drumtaper,etc.),7,thecylindercorrosion,pulling,8,thedoublepistonrodnutistootight,makingitconcentric.

Exclusionmethod:1.Addexhaustdevice;ifthereisnoexhaustdevice,thehydraulicsystemcanbestartedtomaketheworkingpartmovequicklywithmaximumstroke,forciblyremovetheair.2.Adjustthesealingringsothatitisnottightandthepistonrodcanbeensured.Pullbacksmoothlybyhandwithoutleakage(mostlyallowasmallamountofoilseepage),3,correcttheconcentricityofthetwo,4,straightenthepistonrod,5,checktheparallelismofthehydrauliccylinderandtheguiderailandcorrect,6,honingrepairRe-matchingthepiston,7,slightrepairofrustandburrs,severelymustbehoned,8,thenutshouldnotbetightenedtootight,generallyhandtightenedtokeepthepistonrodinanaturalstate.

b,failurephenomenon:impact

Faultanalysis:1.Thepistonandhydrauliccylindersealedbythegaparetoolarge,thethrottlevalvelosesthethrottlingeffect,andthecheckvalveoftheendbufferfails,andthebufferdoesnotwork.

Remedy:1.Accordingtotheregulations,theclearancebetweenthepistonandthehydrauliccylinderismatchedtoreducetheleakagephenomenon.2.Thecheckvalveandthevalveseataremodified.

c,failurephenomenon:insufficientthrustorworkingspeedgraduallydeclineorevenstop

Faultanalysis:1.TheclearancebetweenthehydrauliccylinderandthepistonistoolargeortheO-ringisdamaged,causingthehighandlowpressurechamberstocommunicatewitheachother.2.Duetotheuseofacertainsectionoftheworkingstroke,thehydrauliccylinderboreispoorlylinear(partialdrums)Shape),causingthehighandlowpressureoilsatbothendsofthehydrauliccylindertocommunicatewitheachother.3.Theoilsealatthecylinderendispressedtootightlyorthepistonrodisbent,sothatthefrictionorresistanceisincreased.4.Theleakageisexcessive.5.Theoiltemperatureistoohighandtheviscosityisreduced.Thespeedofthecylinderthatisintermittentlysealedorpoorlysealedissloweddown.Ifthehighandlowpressureoilchambersatbothendsofthehydrauliccylindercommunicatewitheachother,therunningspeedwillgraduallyslowdownuntilitstops.

Remedy:1.IntermittentreplacementofpistonandhydrauliccylinderwithO-ringseal,2.Honingandrepairinghydrauliccylinderbore,singlepiston,3,looseoilseal,straightpistonrodwithoutoilleakage,4Findleaksandtightenthejoints.5.Analyzethecauseofheatandtrytocooldown.Ifthesealgapistoolarge,useapistonoraddasealring.