公差与互换性国际标准05chapter3 Geometrical tolerance.docx
《公差与互换性国际标准05chapter3 Geometrical tolerance.docx》由会员分享,可在线阅读,更多相关《公差与互换性国际标准05chapter3 Geometrical tolerance.docx(15页珍藏版)》请在冰豆网上搜索。
![公差与互换性国际标准05chapter3 Geometrical tolerance.docx](https://file1.bdocx.com/fileroot1/2023-1/6/3cc92fc8-78b1-4bac-852d-19803d3e49c4/3cc92fc8-78b1-4bac-852d-19803d3e49c41.gif)
公差与互换性国际标准05chapter3Geometricaltolerance
Chapter3
Geometricaltolerance
3.1Introduction
Scopeandfieldofapplication
•ThisInternationalStandardgivestheprinciplesofsymbolizationandindicationontechnicaldrawingsoftolerancesofform,orientation,locationandrun-out,andestablishestheappropriategeometricaldefinitions.Hencetheterm“geometricaltolerances”willbeusedinthisdocumentassynonymouswiththesegroupsoftolerances.
•Geometricaltolerancesshallbespecifiedonlywheretheyareessential,thatis,inthelightoffunctionalrequirements,interchangeabilityandprobablemanufacturingcircumstances.
•Indicatinggeometricaltolerancesdoesnotnecessarilyimplytheuseofanyparticularmethodofproduction,measurementorgauging.
3.2FormandSymbolsfortolerancedcharacteristics
General
•Ageometricaltoleranceappliedtoafeaturedefinesthetolerancezonewithinwhichthefeature(surface,axis,ormedianplane)istobecontained
•Thereare14kindsofgeometricaltoleranceinISO1101;theyareshownintable3-1.
•Accordingtothecharacteristic,whichistobetoleranced,andthemannerinwhichitisdimensioned,thetolerancezoneisoneofthefollowing:
——theareawithinacircle;
——theareabetweentwoconcentriccircles;
——theareabetweentwoequidistantlinesortwoparallelstraightlines;
——thespacewithinacylinder;
——thespacebetweentwocoaxialcylinders;
——thespacebetweentwoequidistantplanesortwoparallelplanes;
——thespacewithinaparallelepiped.
•Thetolerancedfeaturemaybeofanyformororientationwithinthistolerancezone,unlessamorerestrictiveindicationisgiven,forexamplebyanexplanatorynote(seefigures3-8and3-9).
•Unlessotherwisespecified,thetoleranceappliestothewholelengthorsurfaceoftheconsideredfeature.
•Thedatumfeatureisarealfeatureofapart,whichisusedtoestablishthelocationofadatum
•Geometricaltoleranceswhichareassignedtofeaturesrelatedtoadatumdonotlimittheformdeviationsofthedatumfeatureitself.Theformofadatumfeatureshallbesufficientlyaccurateforitspurposeanditmaythereforebenecessarytospecifytolerancesofformforthedatumfeatures.
•
Figure3-1Straightnessorflatnessofasingletolerancedfeature
Thestraightnessorflatnessofasingletolerancedfeatureisdeemedtobecorrectwhenthedistanceofitsindividualpointsfromasuperimposedsurfaceofidealgeometricalformisequaltoorlessthanthevalueofthespecifiedtolerance.Theorientationoftheideallineorsurfaceshallbechosensothatthemaximumdistancebetweenitandtheactualsurfaceofthefeatureconcernedistheleastpossiblevalue.
Possibleorientationsofthelineorsurface:
A1—B1A2—B2A3—B3
Correspondingdistances:
h1h2h3
Inthecaseoffigure1:
h1
ThereforethecorrectorientationoftheideallineorsurfaceisA1—B1.Thedistanceh1istobeequaltoorlessthanthespecifiedtolerance.
•ForthedefinitionofcircularityandCylindricity,thelocationofthetwoconcentriccirclesorcoaxialcylindersshallbechosensothattheradialdistancebetweenthemistheminimum.Possiblelocationofthecentersofthetwoconcentriccirclesortheaxesofthetwocoaxialcylindersandtheirminimalradialdistancesare:
Centre(C1)ofA1locatestwoconcentriccirclesortwocoaxialcylinders.
Centre(C2)ofA2locatestwoconcentriccirclesortwocoaxialcylinderswithminimalradialdistance:
⊿r1and⊿r2.Inthecaseoffigure3-2:
⊿r2<⊿r1.
Figure3-2Thedefinitionofcircularityandcylindricity
ThereforethecorrectlocationofthetwoconcentriccirclesorthetwocoaxialcylindersistheonedesignatedA2.Theradialdistance⊿r2shouldthenbeequaltoorlessthanthespecifiedtolerance.
Table3.1Symbolsfortolerancedcharacteristics
Featuresandtolerances
Tolerancecharacteristics
Symbols
Subclauses
Singlefeatures
Formtolerances
Straightness
3.5.1
Flatness
3.5.2
Circularity
3.5.3
Cylindricity
3.5.4
Singleorrelatedfeatures
Profileofanyline
3.5.5
Profileofanysurface
3.5.6
Relatedfeatures
Orientationtolerances
Parallelism
3.5.7
Perpendicularity
3.5.8
Angularity
3.5.9
Locationtolerances
Position
3.5.10
Concentricityandcoaxiality
3.5.11
Symmetry
3.5.12
Run-outtolerances
Circularrun-out
3.5.13
Totalrun-out
3.5.14
3.3Indicationofgeometricaltoleranceondrawing
Toleranceframe
•Thetolerancerequirementsareshowninarectangularframewhichisdividedintotwoormorecompartments.Thesecompartmentscontain,fromlefttoright,inthefollowingorder(seefigures3-3,3-4and3-5):
Figure3-5
Figure3-4
Figure3-3Tolerancefram
—thesymbolforthecharacteristictobetoleranced;
—thetolerancevalueintheunitusedforlineardimensions.Thisvalueisprecededbythesignфifthetolerancezoneiscircularorcylindrical;
—ifappropriate,theletterorlettersidentifyingthedatumfeatureorfeatures(seefigures3-4and3-5).
•Remarksrelatedtothetolerance,forexample“6holes”,“4surfaces”or“6x”shallbewrittenabovetheframe(seefigures3-6and3-7).
Figure3-7Remarks
Figure3-6Remarks
•Indicationsqualifyingtheformofthefeaturewithinthetolerancezoneshallbewrittennearthetoleranceframeandmaybeconnectedbyaleaderline(seefigures3-8and3-9).
Figure3-9Qualifyingtheformofthefeature
Figure3-8Qualifyingtheformofthefeature
•Ifitisnecessarytospecifymorethanonetolerancecharacteristicforafeature,thetolerancespecificationsaregivenintoleranceframesoneundertheother(seefigure3-10).
Figure3-10Thetolerancespecifications
Tolerancedfeatures
•Thetoleranceframeisconnectedtothetolerancedfeaturebyaleaderlineterminatingwithanarrowinthefollowingway:
—ontheoutlineofthefeatureoranextensionoftheoutline(butclearlyseparatedfromthedimensionline)whenthetolerancereferstothelineorsurfaceitself(seefigures3-11and3-12).
Figure3-12
Figure3-11
—asanextensionofadimensionlinewhenthetolerancereferstotheaxisormedianplanedefinedbythefeaturesodimensioned(seefigures3-13to3-15).
Figure3-15
Figure3-14
Figure3-13
—ontheaxiswhenthetolerancereferstotheaxisormedianplaneofallfeaturescommontothataxisormedianplane(seefigures3-16,3-17and3-18).
Figure3-18
Figure3-16
Figure3-17
•Whetheratoleranceshouldbeappliedtothecontourofacylindricalorsymmetricalfeatureortoitsaxisormedianplanerespectivelydependsonthefunctionalrequirements.
Tolerancezones
•Thewidthofthetolerancezoneisinthedirectionofthearrowoftheleaderlinejoiningthetoleranceframetothefeaturewhichistoleranced,unlessthetolerancevalueisprecededbythesignø,(seefigures3-19and3-20).
Figure3-20
Figure3-19
•Ingeneral,thedirectionofthewidthofthetolerancezoneisnormaltothespecifiedgeometryofthepart(seefigures3-21and3-22).
Figure3-21
Figure3-22
•Thedirectionofthewidthofthetolerancezoneshallbeindicatedwhendesirednotnormaltothespecifiedgeometryofthepart(seefigures3-23and3-24).
Figure3-24
Figure3-23
•Individualtolerancezonesofthesamevalueappliedtoseveralseparatefeaturescanbespecifiedasshowninfigures3-25and3-26.
Figure3-26
Figure3-25
•Whereacommontolerancezoneisappliedtoseveralseparatefeatures,therequirementisindicatedbythewords“commonzone”abovethetoleranceframe(seefigures3-27and3-28).
Figure3-28
Figure3-27
Datums
•Whenatolerancedfeatureisrelatedtoadatum,thisisgenerallyshownbydaumletters.Thesameletterwhichdefinesthedatumisrepeatedinthetoleranceframe.
•Toidentifythedatum,acapitalletterenclosedinaframeisconnectedtoasolidorblankdatumtriangle(seefigures3-29and3-30).
Figure3-29
Figure3-30
•Thedatumtrianglewiththedatumletterisplaced:
•Ontheoutlineofthefeatureoranextensionoftheoutline(butclearlyseparatedfromthedimensionline),whenthedatumfeatureisthelineorsurfaceitself(seefigure3-31).
Figure3-31
—asanextensionofthedimensionlinewhenthedatumfeatureistheaxisormedianplane(seefigures3-32to3-34)
Figure3-34
Figure3-33
Figure3-32
•ifthereisinsufficientspacefortwoarrows,oneofthemmaybereplacedbythedatumtriangle(seefigures3-33and3-34)
—ontheaxisormedianplanewhenthedatumis:
✧theaxisormedianplaneofasinglefeature(forexampleacylinder);
✧thecommonaxisorplaneformedbytwofeatures(seefigure3-35)
Figure3-35
•Ifthetoleranceframecanbedirectlyconnectedwiththedatumfeaturebyaleaderline,thedatumlettermaybeomitted(seefigures3-36and3-37).
Figure3-37
Figure3-36
•Asingledatumisidentifiedbyacapitalletter(seefigure3-38)
•Acommondatumformedbytwodatumfeaturesisidentifiedbytwodatumlettersseparatedbyahyphen(seefigure3-39)
•Ifthesequenceoftwoormoredatumfeaturesisimportantthedatumlettersareplacedindifferentcompartments(seefigure3-40).
•Ifthesequenceoftwoormoredatumfeaturesisnoimportantthedatumlettersareindicatedinthesamecompartment(seefigure3-41).
Figure3-38
Figure3-41
Figure3-40
Figure3-39
Restrictivespecifications
•Ifthetoleranceisappliedtoarestrictedlength,lyinganywhere,thevalueofthislengthshallbeaddedafterthetoleranceandseparatedfromitbyanobliquestroke.
•Inthecaseofasurface,thesameindicationisused.T