1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD AEROSPACE SERIES BS A 346
2、:2000 ISO 3161:1999 ICS 49.030.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW UNJ threads General requirements and limit dimensionsThis British Standard, having been prepared under the direction of the Engineering Sector Committee, was published under the authority of the
3、Standards Committee and comes into effect on 15 January 2000 BSI 01-2000 ISBN 0 580 34016 3 BS A 346:2000 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 3161:1999 and implements it as the UK national standard. It supersedes
4、BS 4084:1996 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee ACE/12, Aerospace fasteners and fastening systems, to Subcommittee ACE/12/1, Aerospace fasteners and fastening systems (International), which has the responsibility to: aid enquirers to unde
5、rstand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on
6、 this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence In
7、dex”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself
8、confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the ISO title page, pages ii and iii, a blank page, pages 1 to 40, an inside back cover and a back cover. The BSI copyright notice displayed in this document indicates when the docu
9、ment was last issued.Referencenumber ISO3161:1999(E) INTERNATIONAL STANDARD ISO 3161 Thirdedition 1999-12-01 AerospaceUNJthreadsGeneral requirementsandlimitdimensions Aronautique et espace Filetage UNJ Exigences gnrales et dimensions limitesii blankISO3161:1999(E)iii Foreword ISO(theInternationalOrg
10、anizationforStandardization)isaworldwidefederationofnationalstandardsbodies(ISO memberbodies).TheworkofpreparingInternationalStandardsisnormallycarriedoutthroughISOtechnical committees.Eachmemberbodyinterestedinasubjectforwhichatechnicalcommitteehasbeenestablishedhas therighttoberepresentedonthatcom
11、mittee.Internationalorganizations,governmentalandnon-governmental,in liaisonwithISO,alsotakepartinthework.ISOcollaboratescloselywiththeInternationalElectrotechnical Commission(IEC)onallmattersofelectrotechnicalstandardization. InternationalStandardsaredraftedinaccordancewiththerulesgivenintheISO/IEC
12、Directives,Part3. DraftInternationalStandardsadoptedbythetechnicalcommitteesarecirculatedtothememberbodiesforvoting. PublicationasanInternationalStandardrequiresapprovalbyatleast75%ofthememberbodiescastingavote. AttentionisdrawntothepossibilitythatsomeoftheelementsofthisInternationalStandardmaybethe
13、subjectof patentrights.ISOshallnotbeheldresponsibleforidentifyinganyorallsuchpatentrights. InternationalStandardISO3161waspreparedbyTechnicalCommitteeISO/TC20, Aircraft and space vehicles, SubcommitteeSC4, Aerospace fastener systems. Thisthirdeditioncancelsandreplacesthesecondedition(ISO3161:1996),w
14、hichhasbeentechnicallyrevised.INTERNATIONALSTANDARD ISO3161:1999(E)1 AerospaceUNJthreadsGeneralrequirementsandlimit dimensions 1 Scope ThisInternationalStandardspecifiesthegeneralrequirementsandlimitdimensionsofinchseriesUNJthreadswith controlledrootradiusforaerospaceconstruction. Itdeterminesthebas
15、ictriangularprofileforthistypeofthreadandgivesasystemfordesignatingthediameterand numberofthreadsperinchcombinations.Foralldiameters0,060in(1,524mm)to6,000in(152,4mm),itoffersin theformoftablesthebasicdimensionsandtolerancesforaselectionofdiameterandnumberofthreadsperinch combinations.Italsoprovides
16、themethodofcalculationforthedimensionsandtolerancesforanydiameterand numberofthreadsperinchcombinationnotgiveninthetables,includingthreadswithadiameterinexcessof 6,000in. 2 Normativereference Thefollowingnormativedocumentcontainsprovisionswhich,throughreferenceinthistext,constituteprovisionsof thisI
17、nternationalStandard.Fordatedreferences,subsequentamendmentsto,orrevisionsof,anyofthese publicationsdonotapply.However,partiestoagreementsbasedonthisInternationalStandardareencouragedto investigatethepossibilityofapplyingthemostrecenteditionofthenormativedocumentindicatedbelow.For undatedreferences,
18、thelatesteditionofthenormativedocumentreferredtoapplies.MembersofISOandIEC maintainregistersofcurrentlyvalidInternationalStandards. ISO15872: 1 , Aerospace UNJ threads Gauging. 3 Termanddefinition ForthepurposesofthisInternationalStandard,thefollowingtermanddefinitionapply. 3.1 basicprofile inanaxia
19、lplan,thetheoreticalprofilecorrespondingtothebasicdimensions SeeFigure1. 4 Basicprofile 4.1 Symbols SeeFigure1. 1 Tobepublished.ISO3161:1999(E) 2 4.2 Basicprofiledimensions SeeFigure1andTable1. ValuesgiveninTable1havebeencalculatedaccordingtothefollowingformulae: P n 1 n P 1 HP P n 3 2 0866025 08660
20、25 , , 9 16 048714 048714 HP n , , 3 0,32476 0,32476 8 HP n 5 16 027063 027063 HP n , , H P n8 010825 010825 , , 4.3 Basicdimensionsofthread ValuesgiveninTable2havebeencalculatedaccordingtothefollowingformulae: DD HD PD n 2 2 3 8 0649519 0649519 F H G I K J , , dd Hd Pd n 2 2 3 8 0649519 0649519 F H
21、 G I K J , , DD HD PD n 1 2 9 16 097428 097428 F H G I K J , , dd Hd Pd n 1 2 9 16 097428 097428 F H G I K J , , Thetolerancesshallbeappliedtothebasicprofile.ISO3161:1999(E)3 where D isthebasicmajordiameterofinternalthread D 2 isthebasicpitchdiameterofinternalthread D 1 isthebasicminordiameterofinte
22、rnalthread d isthebasicmajordiameterofexternalthread d 2 isthebasicpitchdiameterofexternalthread d 1 isthebasicminordiameterofexternalthread H istheheightoffundamentaltriangle P isthepitch n isthenumberofthreadsperinch a Axisofthread Figure1Basicprofile 5 Seriesofthreads 5.1 General ThisInternationa
23、lStandardincludesvariousseriesofthreads,i.e.groupsofdiameterandnumberofthreadsper inchcombinationsdistinguishedfromeachotherbythenumberofthreadsperinchassociatedwithanygiven threaddiameter.TheseseriesofthreadsaregiveninTable3. 5.2 Diameters Columns1and2ofTable3givetheprimaryandsecondaryseriesnominal
24、sizeswhichsatisfycurrent requirements.ISO3161:1999(E) 4 5.3 Numberofthreadsperinch(n) 5.3.1 General Columns3to9(inclusive)ofTable3givethenumbersofthreadsperinchwhicharerecommendedtobe associatedwiththediametersincolumns1and2.Thesecolumnsofthenumbersofthreadsperincharedivided intotwogroups: serieswit
25、hincreasing(progressive)pitches:columns3,4and5; constant(uniform)pitchseries:columns6,7,8and9. 5.3.2 Serieswithincreasing(progressive)pitches Therearethreeseriesofincreasingpitches.Theyareheaded“Coarsepitch“,“Finepitch“and“Extrafinepitch“in accordancewithcurrentpractice. Thesetermsindicatetherelativ
26、epitchesofthethreeseriesforeachgiventhreaddiameteranddonotimplya differenceinqualitybetweentheseries. 5.3.3 Constant(uniform)pitchseries Inadditiontothesethreeseriesofincreasingpitches,Table3includesdetailsofconstantpitchserieswhichhave beenselectedfromtherangeof8threadsperinchto20threadsperinch.Eac
27、hoftheseseriesislimitedtoan appropriaterangeofdiameters. 5.4 Threadsoutsideselection Thethreadsspecifiedin5.3.2and5.3.3andindicatedinTable3meetmostrequirements.Ifotherdiameterand numberofthreadsperinchcombinationsorthreadslargerthan6,000inindiameterarerequired,thentheseshall becalculatedusingtheform
28、ulaein6.3.2. 6 Tolerances 6.1 Lengthofthreadengagementusedforcalculatingthepitchdiametertolerances Thelengthofthreadengagement(L e )(seeFigure2)usedinthisInternationalStandardisequalto thebasicmajordiameterfortheseriesUNJC,UNJFand8UNJ.Thisisapplicableforactuallengthsof engagementbetween1,0Dand1,5D;
29、9PfortheseriesUNJEF,12UNJ,16UNJ,20UNJandallUNJS.Thisisapplicableforactuallengthsof engagementbetween5Pand15P. Forapplicationswithlengthsofengagementnotwithintheabovelimits,thetolerancesonthepitchdiametershall becalculatedaccordingtothecalculationformulaeforT d2 andT D2 ,usingthedesignlengthofengagem
30、entasL e .ISO3161:1999(E)5 Figure2Lengthofengagement 6.2 Positionoftolerances 6.2.1 General Thetolerancesarepositive(+)fortheinternalthreadsandnegative()fortheexternalthreads(thatis,the tolerancesareappliedinthedirectionofminimummaterial). 6.2.2 Internalthread SeeFigure3. a BasicUNJprofile Figure3In
31、ternalthreadtolerancesISO3161:1999(E) 6 6.2.3 Externalthread SeeFigure4. a BasicUNJprofile b d 3 istheexternalthreadprofileminordiameter. Figure4Externalthreadtolerances 6.3 Valuesoftolerancesforprofiledimensionsandtolerancesoftheprofileform 6.3.1 General ValuesindicatedinTables4,5and6havebeencalcul
32、atedaccordingtotheformulaegivenin6.3.2andarebased onthelengthofengagementequaltothatshownin6.1, where isthebasichalf-angleatthebaseofthethreadside,i.e.30; isthemaximumpermissiblevariationofthehalf-angle; T D istheinternalthreadbasicmajordiametertolerance; T D1 istheinternalthreadbasicminordiameterto
33、lerance; T D2 andT d2 arethebasicpitchdiametertolerances; T d istheexternalthreadbasicmajordiametertolerance; T d1 istheexternalthreadbasicminordiametertolerance; T d3 istheexternalthreadprofileminordiametertolerance; P isthemaximumpermissiblepitchvariationofexternalorinternalthreads;ISO3161:1999(E)
34、7 D 2 isthepitchdiameterincrementduetoleadvariationfortheinternalthreads; D 2 isthepitchdiameterincrementduetovariationsinthehalf-anglesfortheinternalthreads; d 2 isthepitchdiameterincrementduetoleadvariationfortheexternalthreads; d 2 isthepitchdiameterincrementduetovariationsinthehalf-anglesforthee
35、xternalthreads. 6.3.2 Calculationformulae Limitsofsizeforuntabulated(UNJS)threadsshallalsobecalculatedusingtheformulaegivenin6.3.2.1and 6.3.2.2. 6.3.2.1 Externalthreads Theformulaeareasfollows: dmax.=d dmin.=dmax.tolerance0,060 P 23 0,060 P 23 :seeTable7,column3. d 2 max.=d 2 =dmax. value0,649519P 0
36、,649519P: see Table 7, column 4. d 2 min.=d 2 max. T d2 T d2 =0,750 00015 00015 0015 3 2 3 ,dLP F H I K e (listedinTable8) d 3 max.=d 3 =d 2 max. value0,50518P 0,50518P:seeTable7,column5. d 3 min.=d 2 min. value0,56580P 0,56580P:seeTable7,column6. Rmax.=0,18042P(listedinTable7,column7) 0,18042P:seeT
37、able7,column7. Rmin.=0,15011P(listedinTable7,column8) 0,15011P:seeTable7,column8. P ddT d 22 2 04 cot , 1,7321 1,7321 tan , d P T P d22 04 1,5 1,5 2 2 Thecalculationformulaeforthetangentofthevariationsofthehalf-angleofthethreadpitchareapproximationsofthe maximumeffectswhenthetwohalf-anglesareequal.I
38、SO3161:1999(E) 8 6.3.2.2 Internalthreads Theformulaeareasfollows: Dmax.=D 2 max.+value0,79386P 0,79386P:seeTable7,column9. Dmin.=D D 2 max.=D 2 min.+T D2 T D2 =0,975 00015 00015 0015 3 2 3 ,dLP F H I K e (listedinTable9) D 2 min.=Dmin. value0,649519P 0,649519P: see Table 7, column 4. D 1 max.=D 1 mi
39、n.+T D1 T D1 forthreadswithmorethan12threadsperinch= 005 003 23 ,PPd F H I K 0,002(listedinTable10) T D1 forthreadswith12threadsperinchorless=0,120P(listedinTable10) D 1 min.=Dmin. value0,97428P 0,97428P: see Table 7, column 10. P DDT D 22 2 04 cot , 1,7321 1,7321 tan , D P T P D22 04 1,5 1,5 3 NOTE
40、 Oncompletionofthecalculations,roundofftofourdecimalpoints,exceptvaluesinTable6whichshallberounded tofivedecimalpoints.Roundupifthefifth,orsixthdecimal,asapplicable,isW5.Keepthefourth,orfifthdecimal,as applicable,ifthenextoneis 5. 6.3.3 Rootradiusofthethread 6.3.3.1 Internalthreads Forinternalthread
41、s,theprofileoftheactualrootofthethreadshallatnopointbebelowthebasicprofilegivenin Figure3.Noparticularradiusisspecified. 3 Thecalculationformulaeforthetangentofthevariationsofthehalf-angleofthethreadpitchareapproximationsofthe maximumeffectswhenthetwohalf-anglesareequal.ISO3161:1999(E)9 6.3.3.2 Exte
42、rnalthreads Forexternalthreads,theprofileoftheactualrootofthethreadshallliewithinthetolerancezoneshowninFigure5. ThelimitvaluesoftherootradiusRarespecifiedinTable4.Theprofileshallbeacontinuousblendedcurve,no partofwhichshallhavearadiusoflessthan0,15011Pandwhichistangentialtothethreadflanksatnotlesst
43、han 0,5625Hthreaddepth.Theprofilemaycomprisetangentflankradiithatareonlyjoinedbyatangentialflatatthe root. a Lowerlimitprofile b Upperlimitprofile c BasicUNJprofile Figure5Radiusattherootofthescrewthread 6.4 Provisionsforcoatedthreads Beforecoating,thedimensionsofthethreadsshallbecompatiblewiththeth
44、icknessofthecoatingselectedand withthelimitdimensionsforfinishedpartsspecifiedinTables5and6. 7 Gauging SeeISO15872. Theradiusofthethreadrootshallbecheckedbyanappropriatemethod.Incaseofdispute,opticalmethodshall beusedasarefereemethod. 8 Designationofthreads 8.1 General Threadsshallbedesignatedasshow
45、nin8.2,8.3,8.4and8.5byindicating,insequence,thenominalsizeininch decimals,thenumberofthreadsperinch,thethreadseriessymbol,thetoleranceclass 4 ,thethreadtype(A externalorBinternal)and,ifnecessary,symbolLHputatthedesignationendforleft-handthreads,followedby referencetothisInternationalStandard. 4 Fort
46、hisInternationalStandard,thereisonlyonetoleranceclass:3.ISO3161:1999(E) 10 8.2 Threadsymbolswithincreasing(progressive)pitches Threadseriessymbol Coarsepitchseries UNJC Finepitchseries UNJF Extrafinepitchseries UNJEF EXAMPLE Aclass3threadofthefinepitchseries(UNJF),ofbasicmajordiameter0,2500in,28thre
47、adsperinch,is designatedasfollows: 0,2500-28UNJF-3A Externalthreads 0,2500-28UNJF-3B Internalthreads 8.3 Threadsymbolswithconstant(uniform)pitches ThethreadseriessymboloftheconstantpitchseriesisdesignatedbythethreelettersUNJ. EXAMPLE1 Aclass3threadoftheconstantpitchseries(UNJ),ofbasicmajordiameter3,
48、500in,12threadsperinch,is designatedasfollows: 3,5000-12UNJ-3A Externalthreads 3,5000-12UNJ-3B Internalthreads EXAMPLE2 Aclass3left-handthread(LH)oftheconstantpitchseries(UNJ),ofbasicmajordiameter3,500in,12threads perinch,isdesignatedasfollows: 3,5000-12UNJ-3A-LH Externalthreads 3,5000-12UNJ-3B-LH I
49、nternalthreads 8.4 Specialthreads Threadsderivedusingtheformulaein6.3.2andnotspecifiedinthisInternationalStandardaredesignatedwith seriessymbolUNJSandtheirdesignationisalwaysfollowedwithlimitdimensions. EXAMPLE1 0,2500-24UNJS-3A MAJORDIA0,2500-0,2428 PITCHDIA0,2229-0,2201 MINORDIA0,2019-0,1965 ROOTRAD0,0075-0,0063 ISO3161 EXAMPLE2 0,4375-24UNJS-3B MINORDIA0,3969-0,4038 PITCHDIA0,4104-0,4141 MAJORDIA0,4375-0
