2026工程维修岗试题及答案

2026EngineeringMaintenancePositionExamQuestionsandAnswers

I.Single-ChoiceQuestions(2pointseach,40pointstotal)

1.Inmechanicaltransmission,ordinaryV-beltdrivesaremainlyusedwhenthecenterdistancebetweenthetwoshaftsis______.

A.Large

B.Small

C.Arbitrary

D.ZeroAnswer:AExplanation:AV-beltdrivetransmitsmotionandpowerthroughthefrictionbetweenthebeltandthepulleys.Itissuitableforoccasionswithalargecenterdistanceandstabletransmission.Ifthecenterdistanceistoosmall,thewrapangleonthesmallpulleywillbeinsufficient,reducingthetransmissioncapacity.

2.Intherollingbearingdesignation6205,"62"indicates______.

A.Deepgrooveballbearing,dimensionseries02

B.Self-aligningballbearing,dimensionseries05

C.Deepgrooveballbearing,dimensionseries05

D.Cylindricalrollerbearing,dimensionseries62Answer:AExplanation:Intherollingbearingdesignation,thethirddigitfromtherightisthedimensionseriescodeandthefourthdigitisthetypecode.6indicatesadeepgrooveballbearing,2isthewidthseriescode,and05istheborediametercode(borediameter25mm).

3.Whichofthefollowingkeyconnectionscanfixthecircumferentialpositionofapartontheshaftandtransmitrelativelylargetorque?

A.Plainkey

B.Woodruffkey

C.Spline

D.TaperkeyAnswer:CExplanation:Splineconnectionshavehighload-carryingcapacityandgoodcenteringandguidanceperformance,makingthemsuitablefortransmittinglargetorquewherehighcenteringaccuracyisrequired.Plainkeysaresimpleinstructurebutcannotbearaxialforce;woodruffkeyshaverelativelysmallloadcapacity;taperkeystransmittorquebyfrictionandhavethedisadvantageofpoorcentering.

4.Thenominaldiameterofanordinarythreadreferstoits______.

A.Majordiameter

B.Minordiameter

C.Pitchdiameter

D.CrestdiameterAnswer:A

5.Inahydraulictransmissionsystem,themainfunctionofthereliefvalveduringnormaloperationisto______.

A.Controlflow

B.Controlsystempressure

C.Changedirection

D.FilterimpuritiesAnswer:BExplanation:Thereliefvalvecontrolsthesystempressurebyadjustingthevalveopening.Itisnormallyclosed,andwhenthesystempressurereachesthesetvalue,itopenstorelieveflow,maintainingthesystempressureconstantorlimitingthemaximumpressure.

6.Ingeartransmission,themainmeasuretopreventfatiguepittingfailureonthetoothsurfaceis______.

A.Increasingthemodule

B.Increasingtoothsurfacehardness

C.Reducingtoothwidth

D.IncreasingthepressureangleAnswer:BExplanation:Toothsurfacefatiguepittingisatypeofsurfacefatiguedamagecausedbyrepeatedcontactstress.Increasingtoothsurfacehardness,improvinglubrication,andincreasingthecomprehensiveradiusofcurvaturecanallimprovecontactfatiguestrength.

7.Whichofthefollowingisacomponentofthestatorofathree-phaseasynchronousmotor?

A.Rotorwinding

B.Statorcore

C.Commutator

D.BrushAnswer:BExplanation:Thestatorofathree-phaseasynchronousmotorconsistsofthestatorcore,statorwinding,andframe.ThecommutatorandbrushesarecomponentsofDCmotors.Therotorwinding(squirrel-cagebarsorwoundrotorwinding)belongstotherotorpart.

8.Whenusingamultimetertomeasureresistance,thetwotestleadsshouldfirstbe______.

A.Short-circuitedandadjustedtozero

B.Open-circuitedandadjustedtozero

C.Connectedinparallelandadjustedtozero

D.ConnectedinseriesandadjustedtozeroAnswer:AExplanation:Beforemeasuringresistance,thetwotestleadsshouldbeshort-circuitedandtheohmiczeroadjustmentknobshouldbeadjustedsothatthepointerpointsto0Ω;otherwise,themeasurementerrorwillincrease.

9.Thestartingcurrentofathree-phaseasynchronousmotorisusually______timestheratedcurrent.

A.1–2

B.4–7

C.10–15

D.20–30Answer:BExplanation:Whenathree-phasesquirrel-cageasynchronousmotorstartsdirectly,becausetheslipislargeandtheinducedcurrentintherotorislarge,thestartingcurrentcanreach4–7timestheratedcurrent.

10.Inelectricshockfirstaid,thefirststepisto______.

A.Immediatelyperformcardiopulmonaryresuscitation

B.Quicklyseparatethevictimfromthepowersource

C.Call120andwaitforrescue

D.RinsetheshockedareawithcoldwaterAnswer:BExplanation:Whensomeoneiselectrocuted,thefirstpriorityistoquicklyseparatethevictimfromthepowersource,andthenperformCPRorothermeasuresaccordingtotheinjurycondition.Neverdirectlypullthevictimwithbarehands.

11.Inweldingoperations,thedistancebetweentheoxygencylinderandtheacetylenecylindershouldgenerallynotbelessthan______m.

A.2

B.5

C.10

D.15Answer:BExplanation:Oxygencylindersandacetylenecylindersshouldbeplacedseparatelywithadistanceofnotlessthan5m,andthedistancefromopenflamesshouldnotbelessthan10m.

12.Inbenchwork,thecommonlyusedtoolforscribingparallellinesis______.

A.Prickpunch

B.Divider

C.Heightgauge(vernierheightscriber)

D.TrysquareAnswer:CExplanation:Aheightgaugecanbeusedtogetherwithasurfaceplatetoaccuratelymarkparallellines.Aprickpunchisusedtomakecenterpunchmarks,adividerisusedforscribingcirclesorarcs,andatrysquareisusedforscribingperpendicularlinesorcheckingrightangles.

13.Whenthetolerancevalueofafitis____,thefittingaccuracyis____.

A.Large;high

B.Small;high

C.Large;low

D.Small;lowAnswer:BExplanation:Thetolerancevaluereflectstheallowablevariationrangeofthedimension.Asmallertoleranceindicatesahighermachiningaccuracyrequirementandhigherfittingaccuracy.

14.Inthestandardtolerancegrades,IT01has______accuracythanIT18.

A.Lower

B.Higher

C.Thesame

D.UncertainAnswer:B

15.Thespecificationofafileisusuallyindicatedby______.

A.Thelengthofthefilebody

B.Thewidthofthefile

C.Theheightofthefileteeth

D.TheweightofthefileAnswer:A

16.Whenawaterpumpisrunning,acommoncauseofinsufficientflowandalower-than-normalpressuregaugereadingis______.

A.Thedischargevalveisopenedtoowide

B.Airleakageinthesuctionpipe

C.Themotorspeedistoohigh

D.ThepipelineresistanceistoosmallAnswer:BExplanation:Airleakageinthesuctionpipereducesthevacuumdegreeatthepumpsuctioninlet(thoughtheactualsuctioncapacityisinsufficient),resultinginreducedflowandlowerdischargepressure.

17.The"FiveFixed"contentsofequipmentlubricationdonotinclude______.

A.Fixedpersonnel

B.Fixedpoints

C.Fixedquality

D.RegularlyreplacingtheequipmentAnswer:DExplanation:The"FiveFixed"lubricationsystemreferstofixedpoints,fixedquality,fixedquantity,fixedperiod,andfixedpersonnel.Itdoesnotinclude"regularlyreplacingtheequipment."

18.InV-belttransmission,excessivebelttensionwillleadto______.

A.Beltslipping

B.Increasedbearingwear

C.Increasedtransmissionratio

D.ExtendedbeltlifeAnswer:BExplanation:Excessivetensionsignificantlyincreasestheloadontheshaftsandbearings,acceleratingbearingwearandshorteningtheservicelifeofthebelt.Insufficienttensioniswhatcausesslipping.

19.Inliftingoperations,awireropeshouldbescrappedwhenthediameterreductionduetowearreaches______oftheoriginaldiameter.

A.5%

B.7%

C.10%

D.15%Answer:B(asspecifiedinGB/T5972)Explanation:Thewireropeshouldbescrappedwhenthediameterwearreaches7%oftheoriginaldiameter.

20.Whichofthefollowingisnotatypeofequipmentmaintenancemode?

A.Correctivemaintenance

B.Preventivemaintenance

C.Condition-basedmaintenance

D.MandatoryscrappingAnswer:D

II.True/FalseQuestions(2pointseach,20pointstotal)

1.Inaplainkeyconnection,thereisaclearancebetweenthetopsurfaceofthekeyandthebottomofthehubkeyway,andtorqueistransmittedthroughthetwosidesurfacesofthekey.Answer:TrueExplanation:Inanordinaryplainkeyconnection,thetwosidesurfacesofthekeyaretheworkingsurfaces.Thetopofthekeydoesnotcontactthebottomofthehubkeyway,leavingaclearance.

2.Slidingbearingshavegreaterstartingfrictionresistancethanrollingbearings.Answer:TrueExplanation:Duringstarting,aslidingbearinghasnotyetformedastableoilfilmandisinastateofboundaryfrictionormixedfriction,sothefrictionresistanceisrelativelylarge.Afterahydrodynamicoilfilmisformed,thefrictioncoefficientbecomesverysmall.

3.Therotationdirectionofathree-phaseasynchronousmotorhasnothingtodowiththephasesequenceofthepowersupply.Answer:FalseExplanation:Therotationdirectionofathree-phaseasynchronousmotordependsonthedirectionoftherotatingmagneticfield,whichisdeterminedbythephasesequenceofthepowersupply.Swappinganytwophasewirescanreversethemotordirection.

4.Inthreadedconnections,ordinaryboltconnectionsrequirethattheboltholebemachinedbytapping.Answer:FalseExplanation:Inordinaryboltconnections,theboltpassesthroughaclearancehole,sotappingisnotrequired.Tappingisonlyneededforscrewconnectionsorstudconnectionswherethreadsaremachinedintheconnectedparts.

5.Amegohmmeterisusedtomeasuretheinsulationresistanceoflow-voltageelectricalequipment,andthereisnoneedtodischargebeforemeasurement.Answer:FalseExplanation:Beforemeasurement,thepowerofthetestedequipmentmustbecutoffandtheequipmentfullydischargedtoavoidelectricshockordamagetotheinstrument.Dischargeisalsorequiredaftermeasurement.

6.Thepressureofahydraulicsystemdependsontheexternalload.Answer:TrueExplanation:Inahydraulicsystem,thepressureisdeterminedbytheload.Thegreatertheload,thehigherthesystempressure.Thereliefvalveonlylimitsthemaximumpressureofthesystem.

7.Whenfiling,thefileshouldmoveinastraightlinealongitslengthdirection,applyingpressureduringtheforwardpushbutnotduringthereturnstroke.Answer:TrueExplanation:Duringtheforwardstroke,thefilecutsmetalandpressureshouldbeapplied.Duringthereturnstroke,nocuttingoccurs,sothefileshouldbeslightlyliftedornopressureappliedtoextendthefilelifeandensurefilingquality.

8.Mechanicalsealshavelessleakagethanpackingsealsandaresuitableforhigh-speedandhigh-pressureapplications.Answer:TrueExplanation:Mechanicalsealsrelyonthecontactofendfacestoachievesealing,withextremelylowleakage,andtheirpressureandspeedresistancearesuperiortopackingseals,butinstallationaccuracyrequirementsarehigher.

9.Equipmentinspectioncanbedividedintodailyinspection,periodicinspection,andspecialinspection.Answer:TrueExplanation:Equipmentinspectionisdividedbyperiodandcontentintodailyinspection,periodicinspection,andspecialinspection.Itisthefoundationofpreventivemaintenance.

10.Thehigherthehardnessofametallicmaterial,thebetteritstoughness.Answer:FalseExplanation:Hardnessandtoughnessareusuallycontradictory.Thehigherthehardness,thelowerthetoughness,andthematerialbecomesbrittleandpronetobrittlefracture.

III.Short-AnswerQuestions(8pointseach,24pointstotal)

1.BrieflydescribethestepsandprecautionsforreplacingaV-belt.

Answer:

(1)LoosenthemotormountingboltsandmovethemotortowardthepulleyssothattheV-beltloosens,thenremovetheoldbelt.

(2)Checkwhetherthepulleygroovesarewornordeformed,andcleanoilanddirtfromthegrooves.

(3)SelectaV-beltofthesametype,specification,andlength.Oldandnewbeltsshouldnotbemixed.

(4)Installthenewbeltintothepulleygroovesinturn,andadjustthemotorpositionsothatthebelttensionismoderate(thedepressionatthemiddleofthebeltwhenpressedbythethumbshouldbeabout1/100to1/50ofthecenterdistancebetweenthepulleys).

(5)Checktheparallelismofthetwopulleyshaftsandperformatrialrun.Explanation:WhenreplacingaV-belt,avoidforciblypryingthebeltintothepulleygroovestopreventdamagingthebeltorthepulleys.Formultiple-beltdrives,replacethemasasettoensureuniformloading.

2.Whatisthe"three-levelmaintenancesystem"forequipment?Brieflyexplainitscontents.

Answer:

The"three-levelmaintenancesystem"isawidelyadoptedequipmentmaintenancesysteminChineseenterprises.Itscontentsinclude:

(1)Dailymaintenance:pre-shiftinspection,in-shiftobservation,andpost-shiftcleaning,performedbytheoperator.

(2)First-levelmaintenance(periodicmaintenance):mainlyconductedbytheoperatorwiththeassistanceofmaintenanceworkers,involvingpartialdisassembly,cleaning,adjustment,andlubricationoftheequipment.

(3)Second-levelmaintenance(maintenanceandrepair):mainlyconductedbymaintenanceworkerswiththeparticipationofoperators,involvingpartialdisassemblyandinspection,repairingorreplacingwornparts,andrestoringpartialaccuracyoftheequipment.Explanation:Thecoreofthethree-levelmaintenancesystemis"preventionfirst,combiningmaintenanceandrepair."Throughgradedmaintenance,theresponsibilitiesofoperatorsandmaintenanceworkersareclarified,extendingequipmentlifeandreducingbreakdowndowntime.

3.Brieflydescribethecommoncausesforathree-phaseasynchronousmotorfailingtostartandthetroubleshootingideas.

Answer:

Commoncauses:

(1)Powersupplyfailure:phaseloss,toolowvoltage,orpoorcontactofthepowerswitch.

(2)Motorfailure:opencircuitorshortcircuitinstatorwinding,brokenrotorbars,orseizedbearings.

(3)Loadreasons:excessivemechanicalload,blockedtransmissiondevice,orlockedload.Troubleshootingideas:Firstuseamultimetertocheckwhetherthepowersupplyvoltageisnormalandwhetherthethreephasesarebalanced;thenrotatetheshaftbyhandtojudgewhetherthemechanicalpartisblocked;thenopenthemotorterminalboxtomeasuretheDCresistanceandinsulationresistanceofthewindingstojudgewhetherthemotoritselfisfaulty;ifnecessary,performano-loadtrialruntodistinguishelectricalfaultsfrommechanicalfaults.Explanation:Followtheorder"powersupplyfirst,thenmotor,thenload"toeliminatethesimplestandmostlikelycausesfirst,avoidingblinddisassemblyoftheequipment.

IV.CalculationQuestion(8points,8pointstotal)

1.InanordinaryV-beltdrive,thediameterofthedrivingpulleyisd1=100mm,thediameterofthedrivenpulleyisd2=250mm,andthespeedofthedrivingpulleyisn1=1440r/min.Iftheslipcoefficientofthebeltdriveisε=0.02,find:

(1)thetheoreticaltransmissionratioi;

(2)theactualspeedn2ofthedrivenpulley.

Answer:

(1)Thetheoreticaltransmissionratiois

i=n1n2=d2d1=250100=2.5

(2)Consideringelasticsliding,theactualtransmissionratiois

i′=d2d1(1−ε)

Theactualspeedofthedrivenpulleyis

n2=n1i′=d1(1−ε)d2n1=100×(1−0.02)250×1440=564.48 r/min

Answer:Thetheoreticaltransmissionratiois2.5,andtheactualspeedofthedrivenpulleyisapproximately564.5 r/min.

Explanation:ElasticslidingalwaysexistsinV-beltdrives,sotheactualspeedofthedrivenpulleyislowerthanthetheoreticalvalue.Thesliprateistheratioofthedifferencebetweenthebeltspeedonthedrivingpulleyandthebeltspeedonthedrivenpulley.Inthecalculation,thedrivingpulleydiameteriscorrectedbyd1(1−ε).

V.CaseAnalysisQuestion(8points,8pointstotal)

1.Acentrifugalpumpinaworkshopshowsabnormalvibrationandnoiseduringoperation.Thedischargepressuregauge