SIST EN 1337-7:2004
(Main)Structural bearings - Part 7: Spherical and cylindrical PTFE bearings
Structural bearings - Part 7: Spherical and cylindrical PTFE bearings
This European Standard deals with the requirements for the design and manufacture of spherical and cylindrical PTFE bearings. The requirements and properties of the curved sliding surfaces are included in
EN 1337-2. Spherical and cylindrical bearings with an included angle 2 q > 60° and 2 q > 75° respectively are beyond the scope of this European Standard. (see Figure 6).
For the purpose of controlling the degree of freedom the bearings may be combined with flat sliding elements and guides according to EN 1337-2:2004 and restraining rings as per 6.3.4.
Cylindrical bearings are susceptible to unexpected moments about the transverse axis of the cylindrical surface.
Additional limitation of application to be taken into consideration is given in clause 1 of EN 1337-2:2004.
Lager im Bauwesen - Teil 7: Kalotten- und Zylinderlager mit PTFE
Diese Europäische Norm betrifft die Anforderungen an die Bemessung und die Herstellung von Kalotten- und Zylinderlagern mit PTFE. Die Anforderungen an und Eigenschaften von gekrümmten Gleitflächen sind in EN 1337-2:2004 geregelt. Kalottenlager mit einem Öffnungswinkel von 2 J > 60° und Zylinderlager mit 2 J > 75° liegen außerhalb des Anwendungsbereiches dieser Europäischen Norm (siehe Bild 6).
Zur Steuerung der Freiheitsgerade der Lagerung dürfen die Lager mit ebenen Gleitteilen und Führungen nach EN 1337-2:2004 und Arretierungsringen nach 6.3.4 kombiniert werden.
Zylinderlager sind gegen unplanmäßige Momente um die Querachse der zylindrischen Gleitfläche anfällig.
Zusätzliche in Betracht zu ziehende Anwendungsbegrenzungen sind in EN 1337-2:2004, Abschnitt 1 angegeben.
Appareils d'appui structuraux - Partie 7: Appareils d'appui cylindriques et sphériques comportant du PTFE
Le présent document européen traite des exigences relatives a la conception et a la fabrication des appareils d'appui cylindriques et sphériques comportant du PTFE . Les exigences et les propriétés se rapportant aux surfaces de glissement courbes sont décrites dans l'EN 1337-2. N'entrent pas dans le domaine d'application de la présente Norme européenne les appareils d'appui cylindriques et sphériques dont l'angle au centre (2 q ) de la surface de glissement est supérieur respectivement a 60° et a 75° (voir la Figure 6).
Dans le but de limiter le degré de liberté des appareils d'appui, il est possible de les combiner avec des éléments de glissement plans et des guides conformes a l'EN 1337-2:2004 et avec des butées annulaires conformes au 6.3.4.
Les appareils d'appui cylindriques sont sujets a des moments non prévus autour de l'axe transversal de la surface cylindrique.
Une limitation d'application supplémentaire a prendre en compte est donnée a l'Article 1 de l'EN 1337-2:2004.
Konstrukcijska ležišča - 7. del: Sferična in cilindrična PTFE ležišča
General Information
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Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Structural bearings - Part 7: Spherical and cylindrical PTFE bearingsLãþDAppareils d'appui structuraux - Partie 7: Appareils d'appui cylindriques et sphériques comportant du PTFELager im Bauwesen - Teil 7: Kalotten- und Zylinderlager mit PTFE91.010.30Technical aspectsICS:SIST EN 1337-7:2004enTa slovenski standard je istoveten z:EN 1337-7:200401-junij-2004SIST EN 1337-7:2004SLOVENSKI
STANDARDSIST EN 1337-7:20011DGRPHãþD
EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 1337-7March 2004ICS 91.010.30Supersedes EN 1337-7:2000English versionStructural bearings - Part 7: Spherical and cylindrical PTFEbearingsAppareils d'appui structuraux - Partie 7: Appareils d'appuicylindriques sphériques comportant du PTFELager im Bauwesen - Teil 7: Kalotten- und Zylinderlager mitPTFEThis European Standard was approved by CEN on 2 January 2004.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2004 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 1337-7:2004: E
EN 1337-7:2004 (E)2ContentspageForeword.3Introduction.41Scope.52Normative references.53Terms and definitions, symbols and abbreviations.54Requirements.95Material properties.96Design requirements.97Manufacturing, assembly and tolerances.128Conformity evaluation.12Annex A (informative)
Method for calculating the eccentricities in spherical and cylindrical PTFEbearings.13Annex B (informative)
Reduced area for curved sliding surfaces.15Annex ZA (informative)
Provisions for the CE marking of cylindrical and spherical PTFE bearings (withor without flat sliding elements) under the EU Construction Products Directive.18
EN 1337-7:2004 (E)3ForewordThis document (EN 1337-7:2004) has been prepared by Technical Committee CEN /TC 167, "Structural bearings",the secretariat of which is held by UNI.This European Standard shall be given the status of a national standard, either by publication of an identical text orby endorsement, at the latest by September 2004, and conflicting national standards shall be withdrawn at thelatest by September 2004.This document has been prepared under a mandate given to CEN by the European Commission and the EuropeanFree Trade Association, and supports essential requirements of EU Directive(s).For relationship with EU Directive(s), see informative annex ZA, which is an integral part of this document.Annexes A and B are informative.This document supersedes EN 1337-7:2000.This European Standard EN 1337 “Structural bearings”, consists of the following 11 Parts:Part 1: General design rulesPart 2: Sliding elementsPart 3: Elastomeric bearingsPart 4: Roller bearingsPart 5: Pot bearingsPart 6: Rocker bearingsPart 7: Spherical and cylindrical PTFE bearingsPart 8: Guide bearings and restrain bearingsPart 9: ProtectionPart 10: Inspection and maintenancePart 11: Transport, storage and installationAccording to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark,Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.
EN 1337-7:2004 (E)4IntroductionThis standard considers a minimum operating temperature of –35°C.An extension down to –40°C will be considered in a future amendment.Applications beyond the range of temperature given in clause 1 need special consideration not covered by thisstandard. Characteristics, requirements and test procedures given in this standard do not apply in such cases.
EN 1337-7:2004 (E)51 ScopeThis European Standard deals with the requirements for the design and manufacture of spherical and cylindricalPTFE bearings. The requirements and properties of the curved sliding surfaces are included in EN 1337-2.Spherical and cylindrical bearings with an included angle 2 q > 60° and 2 q > 75° respectively are beyond thescope of this European Standard. (see Figure 6).For the purpose of controlling the degree of freedom the bearings may be combined with flat sliding elements andguides according to EN 1337-2:2004 and restraining rings as per 6.3.4.Cylindrical bearings are susceptible to unexpected moments about the transverse axis of the cylindrical surface.Additional limitation of application to be taken into consideration is given in clause 1 of EN 1337-2:2004.2 Normative referencesThis European Standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate places in the text and the publications are listed hereafter. Fordated references, subsequent amendments to or revisions of any of these publications apply to this EuropeanStandard only when incorporated in it by amendment or revision. For undated references the latest edition of thepublication referred to applies (including amendments).EN 1337-1:2000, Structural bearings - Part 1: General design rulesEN 1337–2:2004, Structural bearings - Part 2: Sliding elementsprEN 1337–5:1996, Structural bearings - Part 5: Pot bearings3 Terms and definitions, symbols and abbreviations3.1 Terms and definitionsFor the purposes of this European Standard, the following terms and definitions apply.3.1.1backing platemetallic component which supports sliding materials3.1.2cylindrical PTFE bearingbearing consisting of a backing plate with a convex cylindrical surface (rotational element) and a backing plate witha concave cylindrical surface between which a PTFE sheet and the mating material form a curved sliding surface(see Figure 1). Cylindrical PTFE bearings are also used in combination with flat sliding elements and guides to formfree or guided bearings (see Figure 2)NOTENumbers in brackets in Figures 1 and 2 refer to the examples shown in Figure 1 of EN 1337-1:2000.
EN 1337-7:2004 (E)6Keya) Fixed by end stops and sliding surface (7.1)b) Without end stops for displacements in y direction (7.2)Figure 1 — Cylindrical PTFE bearingsKeya) Free for displacements in any direction (7.4)b) Guided by an internal guide for displacements in x direction (7.3)c) Guided by external guides for displacements in x directionFigure 2 — Cylindrical PTFE bearings combined with flat sliding elements3.1.3guidesliding element which restrains a sliding bearing from moving in one axis3.1.4lubricantspecial grease used to reduce the friction and wear in the sliding surfaces3.1.5mating surfacehard smooth metallic surface against which the PTFE slides3.1.6polytetrafluoroethylene (PTFE)thermoplastic material used for its low coefficient of friction
EN 1337-7:2004 (E)73.1.7sliding materialsmaterials which form sliding surfaces3.1.8sliding surfacecombination of a pair of flat or curved surfaces of different materials which allow relative displacements3.1.9spherical PTFE bearingbearing consisting of a backing plate with a convex spherical surface (rotational element) and a backing plate witha concave spherical surface between which a PTFE sheet and the mating material form a curved sliding surface(see Figure 3)Spherical PTFE bearings are also used in combination with flat sliding elements and guides to form free andguided bearings (see Figures 4 a) to 4 c)). Spherical PTFE bearings combined with a flat sliding element can beused together with a restraining ring to form fixed bearings (see Figure 4 d))NOTE 1Numbers in brackets in Figures 3 and 4 refer to the examples shown in Figure 1 of EN 1337-1:2000.NOTE 2Fixed by sliding surface (3.2).Figure 3 — Spherical PTFE bearingKeya) Free for displacements in any direction (3.5)b) Guided by an internal guide for displacements in one direction (3.4)c) Guided by external guides for displacements in one direction (3.3)d) Fixed by a restraining ring (3.1)Figure 4 — Spherical PTFE bearings combined with flat sliding elements
EN 1337-7:2004 (E)83.2 SymbolsThe most frequently occurring symbols are defined below. Those that are local, and unique to a particular clause,are defined at their first appearance.3.2.1 Latin upper case lettersAcontact area of sliding surface; projected area of the curved sliding surfacemm2Ldiameter or diagonal of the projected area of the PTFE sheet .mmFigure 5 — Plan dimensions of spherical and cylindrical bearingsNaxial or normal force.N; kNVlateral or shear force.N; kN3.2.2 Latin lower case lettersaminor side of the projection in plan of
cylindrical PTFE surfaces.mmbmajor side of the projection in plan of cyclindrical PTFE surfaces;distance from the projected area of the curved sliding surface.mmcdimension.mmddiameter .mmeeccentricity .mmfnominal compressive strength .N/mm2hprotrusion of PTFE sheet from its recess .mmrradius of curvature .mmtthickness .mmxlongitudinal axisytransverse axiszaxis normal to the principal bearing surface3.2.3 Greek lettersarotation angle.radians
EN 1337-7:2004 (E)9bdeviation angle from vertical axis of the line of action of theapplied load.degrees, radiansDzmaximum deviation of plane or curved sliding surfaces fromtheoretical surface .mmqhalf included angle of PTFE curved surfaces.degrees, radianslratio, coefficientmcoefficient of frictionsnormal pressure .N/mm23.2.4 Subscriptsbbacking plateddesign valueminminimumpPTFESinternal forces and moments from actionsttotal3.3 AbbreviationsPTFEPolytetrafluoroethyleneNDPNationally Determined Parameters4 Requirements4.1 GeneralCylindrical PTFE bearings shall permit rotational movements about one axis, spherical PTFE bearings about anyaxis. They shall be capable of transferring specified forces between superstructure and substructure.4.2
Requirements for load bearing capacityThe curved PTFE sheet shall meet the requirements given in 6.2.1 to 6.2.3 and the backing plate with concavesurface those given in 6.3.3.4.3
Requirements for rotation capabilityThe sliding surfaces shall meet the requirements given in 6.2.4 and clause 4 of EN 1337-2:2004.5 Material propertiesThe materials to be used and the properties to be verified shall be in accordance with clause 5 of EN 1337-2:2004.6 Design requirementsNOTEThis clause gives requirements for the design of components which are specific to spherical and cylindrical bearingsand which are in addition to those given in clause 6 of EN 1337-2:2004.
EN 1337-7:2004 (E)106.1 Design principlesFor design calculations the principles given in clause 5 of EN 1337-1:2000 shall be taken into account.NOTEThe design values of internal forces and moments as well as of movements should be available from a bearingschedule as shown in annex B of EN 1337-1:2000.6.2 Design verification for curved sliding surfaces6.2.1 GeneralFor the purpose of verifications as per 6.2.2 and 6.2.3 the curved sliding surface shall be replaced by its projectionon a plane surface as shown in Figure 6.Key1Projected areaFigure 6 — Verification scheme for the curved sliding surface (example)Internal forces and moments acting on the curved sliding surface due to frictional resistance, externally appliedhorizontal loads and the rotated condition of the bearing shall be taken into account when determining the resultingtotal eccentricity et of the axial force NS.Secondary effects due to the action of the restraints shall also be considered.NOTEIn annex A of this standard, formulae are given for the evaluation of the eccentricities in the most common cases.The frictional resistance shall be determined using the coefficients of friction given in Table 11 of EN 1337-2:2004.6.2.2Separation of sliding surfacesNOTE Separation of the sliding surfaces may lead to wear due to contamination and increased deformation due to lack ofconfinement. As this could endanger long term fitness for use, the condition sp = 0 is considered as
serviceability limit state.It shall be verified that sp ³ 0 under the characteristic combination of actions. In doing so the sliding material shallbe assumed to be linear elastic and the backing plates shall be deemed to be rigid. The condition sp ³ 0 is satisfiedwhen the total eccentricity et falls within the kernel of the projected area.For spherical bearings this condition is satisfied when:
EN 1337-7:2004 (E)11Dimension L is shown in Figure 5.6.2.3Compressive stress verificationNOTE 1Excessive pressure may cause loss of the sliding function and this may lead to structural failure or states close tostructural failure. Therefore this condition is considered as ultimate limit state.The following conditions shall be verified under a fundamental combination of actions:whereNSdis the design axial force at ultimate limit statefk characteristic value of compressive strength for PTFE sheets (see Table 10 of EN 1337-2:2004)Aris the reduced contact area of the curved sliding surfaceNOTE 2The gm value should be given in NDP. Recommended value is gm = 1,4 (see clause 6.8.3 of EN 1337-2:2004).The reduced area Ar is given by the formula:Ar = l´AwhereAis the area of the projected curved sliding surface (see Figure 6)l is a coefficient given in annex B6.2.4Rotation capabilityUnder the fundamental combination of actions
it shall be shown that¾ the metallic surfacing mating with the PTFE material is so proportioned that it completely covers the PTFEsheet,¾ there is no contact between the upper and the lower part of the bearing or any other metallic component (seeEN 1337-1:2000, annex A).For the verification of the above conditions the increase of rotation, specified in clause 5.4 of EN 1337-1:2000, shallbe taken into account.)2(rmkSdAfN´£g)1(8Let£
EN 1337-7:2004 (E)126.3 Design details6.3.1 GeneralFor basic design features clause 7 of EN 1337-1:2000 applies.The permissible material combinations of curved sliding surfaces are given in Table 9 of EN 1337-2:2004.6.3.2 Curved PTFE sheetThe curved PTFE sheet may be attached to either the convex or the concave backing plate.The design details of curved PTFE sheet shall be in accordance with 6.2.1 of EN 1337-2:2004.6.3.3 Backing plates with concave surfacesFor cylindrical and spherical bearings, backing plates with concave surfaces shall be verified in accordance with6.9 of EN 1337-2:2004.Dimensional limitations of backing plates with concave surfaces are shown in Figure 7.Figure 7 — Dimensional limitations of a backing plate with a concave surface.6.3.4 Restraining ringFree spherical bearings (see Figure 4 a)) may be fixed by a steel restraining ring as shown in Figure 4 d).For design and verification, the design rules for pot and piston of pot bearings given in clause 6 of prEN 1337-5:1996 shall be followed.7 Manufacturing, assembly and tolerancesRequirements for flat and curved sliding surfaces are given in clause 7 of EN 1337-2:2004.Protrusion “h” of curved PTFE sheets shall be measured as shown in Figure 2 of EN 1337-2:2004.8 Conformity evaluationConformity to this Part shall be demonstrated in accordance with relevant subclauses of clause 8 of EN 1337-2:2004. The given systems of attestation of conformity (see ZA.2) are also valid for non-serial productions.
EN 1337-7:2004 (E)13Annex A(informative)Method for calculating the eccentricities in spherical and cylindrical PTFEbearingsA.1 GeneralFrictional forces, forces from applied horizontal loads and the rotated condition of the bearing produce eccentricityof the axial force NS, which is used in the verification of PTFE sheets, the adjacent structural members and theanchoring devices.This annex gives methods for calculating the significant eccentricities.Depending on the design features of a particular bearing, additional eccentricities may exist.When several eccentricities occur in a cross-section under consideration, they need to be added.A.2 Friction resistanceA.2.1 Curved sliding surfacesIn the presence of rotational movements, in both cylindrical and spherical bearings, an internal moment occurs dueto the frictional resistance.Regardless of whether the bearing has one or two surfaces, the associated eccentricity e1 is:e1 = mmax ´ r(A.1)The coefficient of friction mmax is given in Table 11 of EN 1337-2:2004.A.2.2 Sliding surfaces w
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