最新Chapter10 Gears 机械零件设计英文PPT全套教案教学讲义ppt.ppt 73页

Chapter10Gears机械零件设计英文PPT全套教案 10.1TypesofGearsSelectionofthetypeofgearingdependsuponmanyfactors:geometricarrangement,reductionratio,power,speedsofrotation,efficiency,noise-levellimitations,andcost.Threeshaftingarrangementsforthetransmissionofpowerormotionfromonerotatingshafttoanother:(1)applicationsinwhichtheshaftaxesareparallel,(2)applicationsinwhichshaftaxesintersect,(3)applicationsinwhichshaftaxesareneitherparallelnodotheyintersect. SometypesofGearsinApplicationclassifiedaccordingtothemutualpositionofshaftsStraight-toothspurgearsimposeonlyradialloadsonsupportingbearings.Theirtoothprofilesareordinarilyinvoluteinshapeandsmallvariationsincenterdistancearethereforeusuallywelltolerated.Althoughspurgearscanbeusedatspeedsashighasothertypesofgears,theyareusuallylimitedtopitch-linevelocitiesaround20m/stoavoidhigh-frequencyvibrationandunacceptablenoiselevels. Asforaccuracyofgears,theelementsofgearwheelsandhousingshouldbemanufacturedwithsufficientaccuracyinordertoensurenormaloperationofgearset.Thedegreeofaccuracyisspecifieddependingonthekindofserviceofthegearandthedemandsithastomeet.Bythehousingdesignitgivestheopenorclosedtypegearset:intheclosed-typegearsthelubricantisfedcontinuously,whileintheopentype----periodically.Geartypesclassifiedbyotherfeatures Thestandardsprovidefortwelvedegreesofaccuracy:from1to12,1beingthehighest.Indesigningtoothedgearsthedegreeofaccuracymustbecorrectlyselected.Thedegreesofaccuracies6to9arethosemostcommonlyused.Higheraccuracyincuttingtheteethconsiderablyreducesnoise.Therefore,thewheelsofimportantgearstransmittingmuchpowerathighperipheralvelocitieshavehelicalofherringboneteethofhigheraccuracy. 10.2PotentialFailureModesGearsmaybevulnerabletofailurebyanyofseveralpotentialfailuremodes:breaking-off(fracture),pitting,surfaceabrasionandseizure.Teethusuallyfailduetoconsiderableinadequaciesindesign,inaccuratecalculationordeviationsfromthenormalservice.TheAmericanGearManufacturersAssociation(AGMA)categorizedthevariouskindsofobservedgearfailuresandestablishedastandardizednomenclaturetodescribethem. Figure10.2illustrates,qualitatively,theoperatingregionsinwhicheachofthemorelikelyfailuremodesmaybeexpectedtooccur. Teethmainlybreakoffduetofatigue.Eachtimethetoothengagesandtakesavaryingloadalternatingbendingstressesaredevelopedattheroot.Acrackisthereforeliabletodevelopintheareaofmaximumstressconcentrationatadefiniteloadrate.Ifthecontactismadeeachtimeononesideofthetooth,thecrackusuallyoccursinthetensionzone.Theresistanceofatoothtobendingcanbeimprovedbyincreasingthebeamstrengthofthededendumportionanddecreasingstressconcentrationattheroot.Thiscanbeachievedbyincreasingtheradiusoffillet(forinstance,bymeansofpositivecorrection),improvingthegearrigidity,theaccuracyofmachiningandthemechanicalpropertiesofthewheelmaterial.1)BendingFatigueandFracture Teethmainlybreakoffduetofatigue.Eachtimethetoothengagesandtakesavaryingloadalternatingbendingstressesaredevelopedattheroot.Acrackisthereforeliabletodevelopintheareaofmaximumstressconcentrationatadefiniteloadrate.Ifthecontactismadeeachtimeononesideofthetooth,thecrackusuallyoccursinthetensionzone.Theresistanceofatoothtobendingcanbeimprovedbyincreasingthebeamstrengthofthededendumportionanddecreasingstressconcentrationattheroot.Thiscanbeachievedbyincreasingtheradiusoffillet(forinstance,bymeansofpositivecorrection),improvingthegearrigidity,theaccuracyofmachiningandthemechanicalpropertiesofthewheelmaterial.1)BendingFatigueandFracture Pittingofthetoothsurfacesisthemostfrequentfailureofwheelsinclosed-typecopiouslylubricatedtoothedgears.Itusuallyoccursinthededendumportionnearthelineofaction.Pittingmayberestrictedorprogressive.Theformerfaultariseswithinasmallportionofthewheelwidthduetotemporaryoverloadingofthisportion.Progressivepittingmeansthattheprocessofpitformationspreadsovertheentirewidthofthetoothedwheelsundersufficientlyhighstress.Thegreatertheoilviscositythegreateristhesurfaceendurancelimitoftheteeth.Viscousoileffectivelydampsdynamicloadsontheteethandthusincreasestheservicelifeoftoothedwheels.2)ContactFatigueandPitting Theharderandsmoothertheworkingsurfacesoftheteethare,thegreatertheloadtheycantakewithoutsufferingfrompitting.Sotheresistanceofthetoothsurfacestopittingcanbeimprovedbyincreasingtheirstrength,surfacefinishandemployingcorrectlubricants.Inopen-typegearswherethereislittleornooil,pittingisanextremelyrarephenomenonsincetheinitialcracksdevelopedinsurfacelayerareusuallywornoffbeforetheprogressivepittingsetsin. UndertheactionofexcessiveloadsthesurfaceofsteelteethatHB<350maysufferplasticdeformations,whileatHB>350thesurfacesofcast-ironteethmaybesubjectedtobrittlefailure.Becauseoftherelativemotionbetweenthemeshedsurfaces,adhesiveorabrasivewearmayoccur.Thewearofteethdistortsitsinvoluteprofile,increasesdynamicloadandweakensthededendumportion,aphenomenonleadingtoincreasedstressesattheroot.Toothwearcanbesloweddownbyreducingunitslidingandcompressivestresses,increasingthewearresistanceofthetoothsurfacesandusingcorrectlubricants.3)Otherfailures Seizureariseswhenoilfilmiscrushedunderhighpressuredevelopedinthecontactzone,thesurfacesoftheteethmeshsotightlytogetherthattheadhesivewearbehaviormaydegeneratetogalling.Inlow-speedgearsseizureiseliminatedbytheuseofextremelyviscouslubricantsandinhigh-speedgearsbyanti-scuffinglubricants.Itisdeducedfromabovethatclosed-typegearsshouldbesodesignedastoprecludeallthefaultsmentionedabovewhileopen-typegeardesignsshouldbefreefromthefailureofbreaking-off,wearandplasticdeformationsoftheteeth. 10.3GearMaterialsandHeatTreatmentRequirements:possibletocutandfinishtheteethwiththerequiredaccuracyandtoensuresufficientbeamstrengthundertheactionofvaryingandimpactload,adequatestrengthofthetoothsurfacesandhighresistancetoabrasion.Steelandcastironcanbeusedtoproducewheelsofanyproportions.Thesematerialsareeasilycast,especiallycastiron,whilesteelhasagoodforgeability.Steelisusuallyusedinanormalizedortemperedstate,butagreatvarietyofsteelandthepossibilityofobtainingvariouspropertiesbymeansofheattreatmentallowofthemostfavorablecombinationofrequiredproperties. Themechanicalpropertiesofcarbonsteel(steel35,40,45,50and51)obtainedafterheattreatmentdependonthecross-sectionsizeofthewheel.Themechanicalpropertiesarerarelyaffectedbythewheelsizeforalloysteels.Ofallalloysteels,40Crand40CrNiarepreferedforgears.Finishcuttingofsuchgearsisdoneafterfinalheattreatment;thesurfaceshardnessofthewheelisthereforeHB<350.Inordertoincreasetheload-carryingcapacityandreducetheoveralldimensionsofthegears,gearswithsurfacehardnessaboveHB350areoftenused,achievingbythroughorsurfacehardening,casehardening,cyanidingandnitriding.Through-hardenablealloy:45or40Cr;Carburizingsteel:20Cr,20CrMnTi.Thenitridingalloys:35CrAlAor38CrMoAlA.Steelsandheattreatmentforgears Byathroughhardeningforcarbonandalloysteel:Rc=50-65.Forimportantgears:steel40Cr,40CrNiand40CrNiMoAThemaximumcorehardnessforcarbonsteelshouldneverexceedRc=45,andforalloynickelandmolybdenumsteel—Rc=50,sinceotherwiseimpactstrengthdropssharply.Thedisadvantagesofthroughhardening:warpingandareductioninthetoughnessofthetoothcorewhichreducestoothresistancetobendingunderimpactload.Surfacehardeningforlargegears:thesurfacehardnessobtainedamountstoRc=51-57Casehardeninggivessurfacehardnessoftheteethwhileretainingpropercoretoughness.Steelsandheattreatmentforgears Alloychromiumsteel,15Crand20Cr,ensuresbetterqualityofthegears,reducedwarpingandgreatercorestrength.Whenoverloadsorimpactloadsareanticipatedandwhentheimpactresilienceandplasticpropertiesofthecoreareofspecialimportance,12CrNi3,15CrV,15CrMrTiandotheralloysteelscanbeused.Forgearswithinternaltoothing,38CrMoAlAisoftenemployedfornitriding.Gearswithnitridedteethareemployedforsteadyloadsunderwell-lubricatedconditiontoprecludeorreduceabrasivewear.Largegearsarecastfromcarbonsteelscontaining0.35-0.55%ofcarbon.GearsofcastironHT300,HT400andHT350areoftenemployedtocarrysmallloadinlow-speedopen-type.Sometimestoothedwheelsaremadeformfabriclaminatedandveneerlaminatedphenolicplastics,artificialleatherandfibre.Othermaterialsforgears 10.4SpurGears;ForceAnalysisForceanalysisofspurgears:thedrivingtorqueT1,PeripheralforceRadialforceThenormalforce: Thisnormalforceactsinthecontactplanenormaltothetoothsurfaces(frictionisneglectedbecauseitonlyslightlyaffectstheseforces).Theperipheralforceactsinanoppositedirectiontotheperipheralvelocityonthedrivingwheelandcoincideswithitonthedrivenwheel.Theradialforceisdirectedfromthepointofcontacttowardsthecenterofthewheelwithexternalteethandawayfromthecenterofthewheelwithinternalteeth.Forcedirectionanalysis 10.5SpurGears;StressAnalysisandDesignInprinciple,gear-toothdesignprocedureisnodifferentfromthedesignprocedureforanyothermachineelement;loadingseverityparameters(e.g.,stresses)arecalculatedandcomparedwithcriticalcapacities(e.g.,strengthscorrespondingtogoverningfailuremodes),adjustingmaterialsandgeometryuntilanappropriatesafetyfactororreliabilitylevelisachieved.Inpractice,theresultsobtainedbyapplyingfundamentalprinciplesaretypicallyrefinedbyusingaseriesofexperience-basedmodifyingfactorstoaccountforthevariabilitiesofmanufacturing,operationaldynamics,strength,environmental,andmountingandassembly. 1)CalculationofTeethforSurfaceStrength(1)ThedesignloadUsedforfurthercalculationforthestrengths.Thedesignloadistheloadaccountingforabovevariabilities,bymultiplyingnominalloadcarriedbyagearwithload-influencingcoefficient=KFn TheapplicationfactorKA,asshowninTable10.1,isusedtoaccountforshockorimpactloadingcharacteristicsoftheprimemoverandthedrivenmachine.ThedynamicfactorKVisusedtoestimatetheeffectofdynamicloadingwhenadetaileddynamicsystemanalysisisnotavailable.Themountingfactorisusedtoaccountfornonuniformloaddistributionacrossthetoothfaceduetomanufacturingvariabilities,bearingclearances,andsupportdeflections.Loadinfluencingfactors ThedynamicfactorThedynamicfactorisrelatedtogearingaccuracyandpitchlinevelocity ThemountingfactorThemountingfactordependsonsurfacehardnessandmountingarrangement Whencurvedsurfaces,suchasmeshinggearteeth,arepressedtogether,thetriaxialstressdistributionsatandbelowthesurfacesofthecontactingbodiesmaybedescribedbytheirpertinentHertzcontactstressequations.Hertzfirstdevelopedthecontactstressequationsforparallelcylindersincontact.(2)HertzContactstresses SimulationofcontactbetweengearteethSincecontactinggearteethemulatecylindersincontact,theHertzcylindricalcontactstressequationcanbeappliedtotheteethofmatinggearsbyreplacingtheparameterswithgearterminology.Pittingusuallybeginsintheareaofthelineofaction(pitchcircle).Forthematingmomentinthepitchpoint: Infacthestrengthofthetoothworkingsurfacesdependsnotonlyonthereducedradiusofcurvatureandthemodulusofelasticityofthematerial,butalsoonthequalityofthetoothsurface,onheattreatment,lubrication,etc.Owingtothesimplicityofthisrelation,Hertzcontactequationisstillusedindesigninggears,whilethedifferencebetweenthetheoreticalpresumptionsandtheactualconditionsofloadonthetoothsurfacesiscompensatedforbyusingallowablecompressivestressesfoundexperimentally.ForthiscasethemaximumnormalHertzstresscomponentalongthecenterlinebyusinggeartoothterminologytoaccountforsurfacefatiguewear.Thebasicsurface-pitting-resistanceassessmentismadebycomparingthesurfacefatiguecontactstresswiththeallowablesurfacefatiguestrength.Considerationsonsurfacestrengthdesign (3)Designforsurfacestrengththefactorofoverlap-ratiothereduction-ratio Checkinganddesigncalculationforsurfacestrengthofgears ChoiceofgearwidthratioshouldneverexceedthevaluesgiveninTable10.3.Indesigncalculations,thevaluesgenerallyvarieswithinawiderange:0.1-1.2,andisspecifiedonthebasisofthefollowingconsiderations.Forclosed-typemedium-speedgearsofmediumpoweristakenintherangeof0.4-0.6.Inopen-typegearswheretheaccuracyofassemblyandrigidityofthebearingsisnothigh,≤0.3.Thegreaterthetransittedpower,themorerigidthereductiongearhousingandthemoreaccuratelythegearisdesigned,thelargerthevalueshouldbe.Thepinionwidthissometimesincreasedby5-10mm.Ifthepinionismadefromplasticsitswidthshouldbelessthanthewidthofthewheel. (4)AdmissiblesurfacecontactstressesPublisheddataforsurfacefatiguestrengthareobtainedfromexperimentsongearsandareallindexedtoareliabilityof99percentforalifeofcyclesofone-wayloading.Fordesignlivesotherthancycles,orreliabilityrequirementsotherthan99percent,thestrengthmaybemodified.Thentheadmissiblesurfacecontactstressis Underconstantload,thenumberofloadcyclesNis:Here,nisthegearrevolutionsperminute;istheworkinghoursintheentireservicelife.ZNcanbealsoreadfromFigure10.9.canbeobtainedfromTable10.4.andmaredependentupongearmaterialanditsheattreatment; Lewisexpressionfornominalbendingstressatthetensile-siderootfillet(criticalpointa)duetotransmittedforceis:2)CalculationofTeethforBendingStrengthAgeartoothidealizedasacantileverbeamsubjectedtoanendloadisthetoothformfactor.Note:withagivenformofthetoothSFandhFareproportionaltothemodule,YFdoesnotdependonthemagnitudeofthemodule. ThevaluesofthetoothformfactorcanbefoundgraphicallyintheFig.ThetoothoutlinechangesdependingonitsnumberZandthecorrectionfactorxConsideringtheload-influencingcoefficientK,stressmodifyingfactor,andthefactorofoverlappingeffect,,wecanget DesignformulaThecalculationsforstrengthcheckingThefactorofoverlappingeffectThestressmodifyingfactor ,theallowablebendingstressattheroot,canbecalculatedbyThemagnitudeofallowablebendingstressdependsonthematerialanditsheattreatment,thenatureofloadcarriedbythetooth(ononeoronbothsides),andserviceofthegear.ThebendingendurancelimitcanbefoundfromtheFig.10.8.ThevaluesofthelifeadjustmentfactorandsafetyfactorforbendingstrengthcanbefoundfromabovefigureandTable10.4,respectively.Lifeadjustmentfactor Boththebendingstressintheteethofthepinionandthestressinitsmeshinggearshouldbecheckedby:Whiledesigningby(10-15),themaximumvalueofshouldbeused:Afterobtainingthecomputedmodulebyaboveformula,weshouldapproximateittotheneareststandardvalue. TheresolutionofFnrequirescomponentsFtandFr,andanaxialthrustcomponentFaasshowninFigure10.16.10.6DesigningofHelicalGearsForceanalysisofrighthanddrivenhelicalgear1)Loadanalysisforhelicalgears Similartospurgears,Ftisdirectlyrelatedtopowertransmissionandtorquedeveloped,andradialcomponentFrisa(useless)separatingforcebetweenthedrivingpinionanddrivengear.Thedirectionoftheaxialforcedependsonthedirectionofrotationandtheinclinationoftheteeth.Fig.10.16c)showstheforceswithteethinclinedtotherightonadrivingwheelrotatinganticlockwise.TheaxialforceFa,generatedbytheinclinedhelicalteeth,dictatesthatthesupportbearingsmusthavetheabilitytoresistnotonlytheforcecomponentsFtandFrinthetransverseplane,butalsotheaxialthrustcomponentFa. Thedesignloadforhelicalgearsis:Considering2)Calculationofteethforsurfacestrengththecheckingcalculationsforhelicalgearscanbewrittenas:Forthedesigncalculation: Thehelixanglecoefficientfortoothbending,canbefoundinFig.10.17.Theequivalentnumberofteeth,Zv=,,isusedtofindand3)Calculationofteethforbeamstrength 10.7SummaryofGearDesign1)SuggesteddesignprocedureBasedonfunctionalspecificationsandcontemplatedsystemconfiguration,generateafirstconceptualsketchofthegeartrain,includingrequiredreductionratio,proposednumberofteethforeachgear,gearshaftcenterlinesandbearinglocations,andanyothergeometricalconstraints.Identifypotentialfailuremodes,andselecttentativegearmaterials.Selecttentativemanufacturingandfinishingmethodsappropriatetotheapplication.Tentativelyselectatoothsystem,then,usingspecifiedpowerandspeedrequirements,performacompleteforceanalysistodeterminetorques,speeds,andtransmittedloadsateachmeshinthegeartrain. Calculateatentativediametralpitch(ormodule),basedoncalculationsforsurfaceendurance(orbendingcalculations),whichindicatesthatthereisabalancebetweenfailurebytoothbendingfatigueandsurfacefatiguedurability.Calculatethecenterlinedistance.Foreachgear,calculateorestimatetheothergeometricaldimensionsaswellasthepitchlinevelocities.Ifnecessary,repeatthedesignprocess.Thedesignprocedureforhelicalgearsfollowsthesamepatternasforspurgearsexceptforthecomplicationsintroducedbytheinclinedteeth. Usually,fortheclosed-typegearset,whenthesurfacehardnessisHB<350,thepitchdiameterofthepinionandthecenterdistancearefoundfromthecalculationsofthesurfaceenduranceoftheteeth.Thenthecheckingcalculationofbendingisusedtoseeifthebendingstrengthissecured.WhenthehardnessoftheworkingsurfacesisHB≥350,designcalculationofisusedtofindthemodule,thenotherproportions,finallythesurfaceenduranceischecked.Sincewehavenotestablishedareliablemethodforcalculatinggearwearyet,theoveralldimensionsofanopen-typegeararefoundfromthecalculationsoftheteethforbeamstrengthbuttheweakeningofteethduetoareductioninthicknessbypossibleweariscompensatedforbyacertainincreaseinthemodule.Designprinciplesforgears 2)SomeconsiderationinthedesignofgearsInclosed-typegearsthenumberofteethshouldbeaslargeaspossible(withthesamediameterofthegearsfoundfromthestrengthdesignoftheteethsurfaces).Whentheteethareveryhard(HB>350)andthediametersofthegearsfoundfromcalculationsforsurfaceenduranceoftheteetharesmall,theirnumbermayhavetobedecreasedtoincreasetheirmoduleandtherebyensuretherequiredbeamstrength.Itwaspointedoutthattheuseofangularcorrectionimprovesthesurfacestrengthofteeth.Correctioncanalsoinfluencethebendingstrengthofteeth.Apositiveshiftofthetoolincreasestooththicknessattherootandimprovesthebeamstrengthofthetooth. 1)SuggesteddesignprocedureIfthediameterofthepiniondedendumcircleislargeenoughforthepiniontobesecureddirectlytotheshaftbyanymethod,thepinionismadeseparateformtheshaft(Fig.a).Ifthediameterofthepiniondedendumcirclediffersbutlittlefromtheshaftdiameterthepinionismadeintegralwiththeshaft(Fig.b).10.8StructuralDesignofPinionsandGears Gearsofdiameterlessthan500mmaremadefromopen-dieorclosed-dieforgings(dependingonthescaleofproduction).Forgedwheelsaremadesolidorcoredwithroundholes.Foramoreconvenientclampingorhandling,ortoreduceweight,holesaredrilled.Castwheelswithcrossedspokesareusedwhenda≤1,000mm;Whenda>1,000mm,castwithI-shapedspokes.Whenproducedinlimitedquantitiesandalsotoreduceweightweldingisemployed.. Forlightloads,lowspeeds,lowpowertransmission,andintermittentoperation,unenclosedsetsmaybelubricatedbyusinganoilcan,dripoiler,orperiodicallybrushedgrease.Whengearsoperateinanenclosedhousing,oracase,splashlubricationiswidelyusedforgearingsubjectedtomoderateloads,speeds,andtransmittedpowerlevels.Inthiscase,oneofthegearsinapairdipsintoanoilsupplysumpatthebottomofthegearcaseandcarriestheoiltothemesh.10.9LubricationofGears Forhighspeedsandhigh-capacitygearingsystems,positiveoilcirculationsystemsareoftenrequired,usingaseparatepumptodrawoilfromthesumpanddeliveritatacontrolledratetothemeshingteeth.Thelubricantisselecteddependingonperipheralvelocityandunitload.Table10.5givestherecommendedvaluesofarbitraryviscosityofoilinEngler’sdegrees,thevaluesofoilviscosityat100℃beinggiveninbrackets.Thegradeofoilischosenaccordingtotheviscosityrequired.Themainlossesareduetoslidingfriction,whichdependsonthesurfacefinishoftheteeth,thepropertiesandamountofthelubricant,thevelocityofgearsandthetransmittedload. TheendofChapter10 区分所有概述（物权法第6章）1、区分所有制度的产生根源传统民法理论——一物一权原则——一幢房屋仅能拥有一个所有权——弊端：多人拥有一幢楼房时只能选择共有制度，不适应规模化的小区开发和物业管理，远远不足以规范日趋复杂的住宅商品化、建筑立体高层化和利益多元化的现实需要。因为：A、共同共有：需要共同关系，且处分时要经过其他共有人同意；B、按份共有：处分时其他共有人享优先购买权。55 区分所有概述2、区分所有的基本含义建筑物区分所有制度在德国法上称为“住宅所有权”，法国法中称为“住宅分层所有权”，瑞士法上称为“楼层所有权”，英美法中称为“公寓所有权”。日本和我国台湾称为“区分所有权”，我国大陆学者一般采纳了“建筑物区分所有”概念。概念：是指多个所有人共同拥有一栋建筑物时，各所有人对建筑物专有部分所享有的专有所有权，与对建筑物共用部分所享有的持分权，以及因区分所有人之间的共同关系所生的成员权的总称。56 区分所有概述a、区分所有的根本特征：一幢楼宇被分割成各自独立的单元（区分所有的客体），因而成立相互独立的所有权；b、区分所有的最重要标志：取得专有部分的所有权（专有部分的建筑空间）——是取得共有部分持份权和基于共同关系所生成员权的基础；57 区分所有概述c、区分所有对标的物的基本要求：在同一个标的物上存在一定数量的独立部分，独立部分之间有共同的联结，构成一个整体；区分所有=独立部分专有权+共有部分持份权+因区分所有人之间的共同关系所生的成员权（物业管理权）。58 区分所有概述3、区分所有和共有的区别a、共有不是一种独立的所有权形式，区分所有在一个物上成立多个所有权；b、共有关系解除时，共同共有？？按份共有？?c、登记薄册数量不一。59 区分所有概述4、区分所有的法律特征a、是独立的所有权形式；b、有3种权利构成；c、权利主体的身份具有多重性-所有权人（基础）+共有权人+成员权人60 自用部分和专有权1、区分所有的客体——自用部分应当具备2个条件：a、构造上的独立性；b、利用上的独立性。对于自用部分的范围，有空间说、最后粉刷表层说、壁心说、壁心和最后粉刷表层混和说等。61 自用部分和专有权空间说：多数学者所持观点。认为专有权是指区分所有人对专属自己的，由建筑材料构成的，在构造上和使用上具有独立性的封闭建筑空间所享有的所有权。如德国法学家贝尔曼认为，专有权是在“供居住或供其他用途（尤其供营业或办公）之建筑空间上所设立的专有所有权。专有部分的范围包括墙壁、地板和天花板所围成的空间部分。该说的优点在于符合专有权客体的实际状况，缺点在于把墙壁、地板、天花板等境界部视为共有部分，则区分所有权人欲粉刷墙壁或在墙壁上钉图钉，在地板上铺地砖，均应经其他所有人之同意，始得为之。使区分所有人生活感到不便，其与社会实情不相符。62 自用部分和专有权壁心说认为：专有部分的范围达到墙壁、地板、天花板等境界部分厚度的中心线。该说的优点：符合交易习惯，缺点：专有部分之范围既包含至境界壁之中心线，则各区分所有人在未超过壁心范围内，得自由使用或变更，但境界壁内往往埋设着维持整栋建筑物正常使用所必需的各种管线（水管、电线等），若可任凭区分所有人使用或变更，对整栋建筑物之维护与管理，显非妥当。63 自用部分和专有权“最后粉刷表层说”认为：专有部分的范围包括至墙壁、天花板、地板等境界部分表层最后粉刷的部分。该说的优点：弥补了空间说和壁心说的不足，使区分所有人一方面得在自己专有部分上自由装演，另一方面把境界壁最后粉刷以内的部分视为共有部分，有利于整栋建筑物的管理与维护。该说的缺点：忽视当前区分所有建筑物系以壁心为界线之交易习惯。64 自用部分和专有权“壁心和最后粉刷表层混和说”认为：专有部分的范围在区分所有人相互间有关建筑物的维持、管理等内部关系上，包含到墙壁、地板、天花板等境界部分的最后粉刷表层部分，专有部分的范围在针对第三人的买卖、保险、税金等外部关系上包含至境界部分厚度的中心线。此说是对上述三种学说的综合折衷，认为，在区分所有人之间，尤其是有关建筑物的维持、管理关系上，适用最后粉刷表层说，在对第三人的关系（如买卖、保险、纳税）上，则适用壁心说。65 自用部分和专有权评价：第四种学说兼顾了区分所有建筑物内部关系和外部关系的需要，是比较合理的。在内部关系上，将专有部分的范围划定至界壁等的最后粉刷表层，一方面使得专有所有人可以放心大胆地对房屋内墙进行装潢，如粉刷涂料、悬挂物品，而不必担心侵犯其他所有人的权利。否则依据空间说，作为界壁的墙壁和地板、天花板等均属共用部分，则专有所有人在对位于自己房间内的界壁进行装饰时，须事先征得其他共有人的同意，这在现实操作中是不大可能的。66 自用部分和专有权另一方面，由于现代建筑物的墙壁内预先敷设有大量维持建筑物正常使用所必需的各种管线，采用最后粉刷表层说也避免了壁心说带来的弊端。因为按照壁心说，至墙壁等的中心部分皆属专有部分，则区分所有人可以对其任意使用或变更，这样做明显不利于整体建筑物的维护和管理。在外部关系上，比如为购买房屋而计算房屋面积时，计算的便是至墙壁中心的面积，这就是人们通常所说的使用面积，而建筑面积则需再乘以一定的系数，壁心说又较为合理。67 自用部分和专有权2、自用部分专有权和独有房屋所有权的异同：相同点：都是一种排他性支配权，表现在：a、积极方面b、消极方面不同点：a、土地使用权共有b、对房屋四壁拥有不完整的所有权68 自用部分和专有权3、自用部分专有权的权利限制——物权法第71条区分所有人不得违反全体业主的共同利益，表现在：a、维持现状b、不得擅自改变设计c、不得擅自改变物业使用性质d、不得与公用部分分割转让物权法第71条69 公用部分和共有权1、共有部分的本质特征在于：其性质或功能是服务于整个建筑物的使用和全体业主的利益的，理论上概括为：a、共用部位b、公用设施c、共用基地——土地使用权70 公用部分和共有权2、区分所有中的共有权是按份共有，但基于其从属性，使其与一般的按份共有相区别：表现a、b、c3、区分所有人对共用部分的权利和义务：a、权利；b义务物权法第73、74、79、80条71 区分所有中的管理权管理权属于成员权，是区分所有权人对区分所有建筑物的共用部分所享有的共同管理的权利。包括：设立业主大会，选举业主委员会，物权法第75条；共同决定有关重大事项，物权法第76条；决定物业管理事宜，物权法第81、82条遵守法律法规和管理规约，物权法第77、83条。72 几个案例建筑物区分所有权与相邻权的比较建筑物区分所有与土地使用权按份共有优先购买权与建筑物区分所有73