SIST EN 13906-1:2009

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Zylindrische Schraubenfedern aus runden Drähten und Stäben - Berechnung und Konstruktion - Teil 1: DruckfedernRessorts hélicoïdaux cylindriques fabriqués à partir de fils ronds et de barres - Calcul et conception - Partie 1: Ressorts de compressionCylindrical helical springs made from round wire and bar - Calculation and design - Part 1: Compression springs21.160VzmetiSpringsICS:Ta slovenski standard je istoveten z:EN 13906-1:2002SIST EN 13906-1:2009en,fr,de01-julij-2009SIST EN 13906-1:2009SLOVENSKI
STANDARD



SIST EN 13906-1:2009



EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 13906-1April 2002ICS 21.160English versionCylindrical helical springs made from round wire and bar -Calculation and design - Part 1: Compression springsRessorts hélicoïdaux cylindriques fabriqués à partir de filsronds et de barres - Calcul et conception - Partie 1:Ressorts de compressionZylindrische Schraubenfedern aus runden Drähten undStäben - Berechnung und Konstruktion - Teil 1:DruckfedernThis European Standard was approved by CEN on 5 January 2001.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 Management Centre 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 Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2002 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13906-1:2002 ESIST EN 13906-1:2009



EN 13906-1:2002 (E)2Contents1Scope.42Normative references.43Terms, definitions, symbols, units and abbreviated terms.53.1Terms and definitions.53.2Symbols, units and abbreviated terms.64Theoretical compression spring diagram.85Design principles.86Types of Loading.96.1Static and/or quasi-static loading.96.2Dynamic loading.96.3Operating temperature.96.4Transverse loading.106.5Buckling.106.6Impact loading.106.7Other factors.107Stress correction factor k.118Material property values for the calculation of
springs.129Calculation formulae.139.1Spring work.139.2Spring force.139.3Spring deflection.139.4Spring rate.139.5Torsional stresses.149.6Nominal diameter of wire or bar.149.7Number of active coils.149.8Total number of coils.149.9Minimum permissible spring length.149.10Solid length.159.11Increase of outside diameter of the spring when loaded.159.12Fundamental frequency.159.13Transverse loading.159.14Buckling.179.15Impact stress.1810Permissible torsional stresses.1810.1Permissible torsional stress at solid length.1810.2Permissible torsional stress under static or quasi-static loading.1910.3Permissible stress range under dynamic loading.20Annex A (informative)
Examples of relaxation for cold coiled springs.28SIST EN 13906-1:2009



EN 13906-1:2002 (E)3ForewordThis document (EN 13906-1:2002) has been prepared by CEN/CS SUBSECTOR M18, the secretariat of which isheld by CMC.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 October 2002, and conflicting national standards shall be withdrawn at the latestby October 2002.According to the CEN/CENELEC Internal Regulations, the national standards organizations of the followingcountries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland,France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Spain,Sweden, Switzerland and the United Kingdom.This European Standard has been prepared by the initiative of the Association of the European Spring FederationESF and is based on the German Standard DIN 2089- 1 - «Helical compression springs out of round wire and rod;calculation and design» edition 1984-12, which is known and used in many European countries.SIST EN 13906-1:2009



EN 13906-1:2002 (E)41 ScopeThis standard specifies the calculation and design of cylindrical helical compression springs with a linearcharacteristic, made from round wire and bar of constant diameter with values according to Table 1, and in respectof which the principal loading is applied in the direction of the spring axis.Table 1CharacteristicCold coiledcompression springHot coiled compressionspring
1)Hot coiledcompression spring 2)Wire or bar diameterd
17 mm8 mm
d
60 mm9 mm
d
18 mmCoil diameterD
200 mmD
460 mmD
180 mmLength of unloadedspringL0
630 mmL0
800 mmL0
600 mmNumber of active coilsn
2n
35
n
12Spring index4
w
203
w
126
w
12 1) Batch size
5000 parts 2) Batch size > 5000 partsNOTEQuality Standards for compression springs will be developed later.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 10270-1:2001, Steel wire for mechanical
springs - Part
1: Patented cold drawn unalloyed steel spring wire.EN 10270-2:2001, Steel wire for mechanical
springs - Part
2: Oil hardened and tempered spring steel wire.EN 10270-3:2001, Steel wire for mechanical
springs - Part
3: Stainless spring steel wire.EN 12166, Copper and copper alloys - Wire for general purposes.EN ISO 2162-1:1996, Technical product documentation - Springs - Part 1: Simplified representation(ISO 2162-1:1993).EN ISO 2162-3:1996, Technical product documentation - Springs - Part 3: Vocabulary (ISO 2162-3:1993).prEN 10089:2000, Hot-rolled steels for quenched and tempered springs – Technical delivery conditions.SIST EN 13906-1:2009



EN 13906-1:2002 (E)53 Terms, definitions, symbols, units and abbreviated terms3.1 Terms and definitionsFor the purposes of this European Standard, the following terms and definitions apply.3.1.1springmechanical device designed to store energy when deflected and to return the equivalent amount of energy whenreleased.[2.1 from EN ISO 2162-3:1996 ]3.1.2compression springspring that offers resistance to a compressive force applied axially.[2.3 from EN ISO 2162-3: 1996]3.1.3helical compression springcompression spring made from wire of circular, square or rectangular cross-section wound around an axis withdistances between its coils.Helical compression springs are available in cylindrical or other forms, e.g. conical, double- conical (convex: barrelspring; concave: wasted spring) or tapered. [2.9 from EN ISO 2162-3:1996]NOTEIn the following text of this Standard the term spring is used with the meaning of helical compression springSIST EN 13906-1:2009



EN 13906-1:2002 (E)63.2 Symbols, units and abbreviated termsTable 2 contains the symbols, units and abbreviated terms used in this standard.Table 2SymbolsUnitsTermsa0mmgap between active coils of the unloaded spring2ieDDDmmmean diameter of coilDemmoutside diameter of the springDemmincrease of outside diameter of the spring, when loadedDimminside diameter of the springdmmnominal diameter of wire (or bar)dmaxmmupper deviation of dEN/mm²modulus of elasticity (or Young’s modulus)FNspring forceF1,F2 .Nspring forces, for the spring lengths L1, L2. (at ambient temperature of 20C)Fc thNtheoretical spring force at solid length LcNOTEThe actual spring force at the solid length is as a rule greater than the theoreticalforceFKNbuckling forceFnNspring force for the minimum permissible spring length LnFQNspring force perpendicular to the spring axis (transverse spring force)fes-1
(Hz)natural frequency of the first order of the spring (fundamental frequency)GN/mm²modulus of rigidityk-stress correction factor (depending on D/d )Lmmspring lengthL0mmnominal free length of springL1, L2.mmspring lengths for the spring forces
F1, F2.Lcmmsolid lengthLKmmbuckling lengthLnmmminimum permissible spring length (depending upon Sa)mmmmean distance between centres of adjacent coils in the unloaded condition (pitch)N-number of cycles up to rupturen-number of active coilsnt-total number of coilsRN/mmspring rateRmN/mm²minimum value of tensile strengthSIST EN 13906-1:2009



EN 13906-1:2002 (E)7Table 2 (concluded)SymbolsUnitsTermsRQN/mmtransverse spring rateSammsum of the minimum gaps between adjacent active coils at spring length Lnsmmspring deflections1, s2 .mmspring deflections, for the spring forces
F1, F2 .scmmspring deflection, for the solid length, Lcshmmdeflection of
spring (stroke ) between two positionssKmmspring deflection, for the buckling force FK (buckling spring deflection)snmmspring deflection, for the spring force
FnsQmmtransverse spring deflection, for the transverse force FQvStm/simpact speedWN mmspring work,dDw-spring index-spring rate ratio-slenderness ratio-relative spring deflection-seating coefficientkg/dm³densityN/mm²uncorrected torsional stress (without the influence of the wire curvature being takeninto account)1, 2 .N/mm²uncorrected torsional stress, for the
spring forces F1, F2 .cN/mm²uncorrected torsional stress, for the solid length Lck N/mm²corrected torsional stress (according to the stress correction factor k)k1, k2 .N/mm²corrected torsional stress, for the
spring forces F1, F2 .khN/mm²corrected torsional stress range, for the stroke shkH (.)N/mm²corrected torsional stress range in fatigue, with the subscript specifying the number ofcycles to rupture or the number of ultimate cyclesknN/mm²corrected torsional stress, for the
spring force FnkO (.)N/mm²corrected maximum torsional stress in fatigue, with the subscript specifying thenumber of
cycles to rupture or the number of ultimate cycles.kU (.)N/mm²corrected minimum torsional stress in fatigue, with the subscript specifying the numberof cycles to rupture or the number of ultimate cyclesnN/mm²uncorrected torsional stress, for the
spring force FnStN/mm²impact stresszulN/mm²permissible torsional stressSIST EN 13906-1:2009



EN 13906-1:2002 (E)84 Theoretical compression spring diagramThe illustration of the compression spring corresponds to Figure 4.1 from EN ISO 2162-1: 1996.The theoretical compression spring diagram is given in Figure 1.Figure 1 — Theoretical compression spring diagram5 Design principlesBefore carrying out design calculations for a spring, the requirements to be met shall be considered, particularlytaking into account and defining: a spring force and corresponding spring deflection or two spring forces and corresponding stroke or a springforce, the stroke
and the spring rate, loading as a function of time: is static or dynamic, in the case of dynamic loading the total number of cycles, N, to rupture, operating temperature and permissible relaxation, transverse loading, buckling, impact loading, other factors (e.g. resonance vibration, corrosion)NOTEIn order to optimise the dimensions of the spring by taking the requirements into account sufficient working spaceshould be provided when designing the product in which the spring will work.SIST EN 13906-1:2009



EN 13906-1:2002 (E)96 Types of LoadingNOTEBefore carrying out design calculations it should be specified whether they will be subjected to static loading, quasi-static loading, or dynamic loading.6.1 Static and/or quasi-static loadingA static loading is: a loading constant in timeA quasi-static loading is: a loading variable with time with a negligibly small torsional stress range (stroke stress) (e.g. torsional stressrange up to 0,1
fatigue strength) a variable loading with greater torsional stress range but only a number of cycles of up to 1046.2 Dynamic loadingIn the case of compression springs dynamic loading is:Loading variable with time with a number of loading cycles over 104 and torsional stress range greater than0,1
fatigue strength ata) constant torsional stress rangeb) variable torsional stress rangeDepending on the required number of cycles N up to rupture it is necessary to differentiate the two cases asfollows:a) infinite life fatigue in which the number of cycles N
107 for cold coiled springs N
2
106 for hot coiled springsIn this case the torsional stress range is lower than the infinite life fatigue limit.b) limited life fatigue in which N
107 for cold coiled springs N
2
106 for hot coiled springsIn this case the torsional stress range is greater than the infinite life fatigue limit but smaller than the low cyclefatigue limit.In the case of springs with a time- variable torsional stress range and mean torsional stress, (set of torsional stresscombinations) the maximum values of which are situated above the infinite fatigue life limit, the service life can becalculated as a rough approximation with the aid of cumulative damage hypotheses. In such circumstances theservice life shall be verified by means of a fatigue test.6.3 Operating temperatureThe data relating to the permissible loading of the materials used as given in clause 10 apply at ambienttemperature.SIST EN 13906-1:2009



EN 13906-1:2002 (E)10The influence of temperature shall be taken into consideration especially in the case of springs with closelytoleranced spring forces. At operating temperatures below -30°C the reduction of the notch impact strength shallalso be taken into account.6.4 Transverse loadingIf an axially loaded spring with parallel guided ends is additionally loaded perpendicular to its axis, transversedeflection with localised increase in torsional stress will occur, and this shall be taken into account in thecalculation.6.5 BucklingAxially loaded springs have a tendency to buckle when they are compressed to a certain critical length.Consequently, their buckling behaviour shall be checked. An adequate safety against buckling shall be allowed forin the design of these springs, because the buckling limit is reached in practice sooner than calculated theoretically.Springs which cannot be designed with an adequate safety against buckling shall be guided inside a tube or over amandrel. Friction will be the inevitable consequence, and damage to the spring will occur in the long run. It istherefore preferable to split up the spring into individual springs, which are safe against buckling, as far as possible,and to guide these springs via intermediate discs over a mandrel or in a tube.It shall be always borne in mind that the direction of the spring force does not coincide precisely with the geometricaxis of the spring. Consequently, the spring will tend to buckle before the theoretical buckling limit has beenattained. It is very difficult to allow for this effect by calculation. Buckling occurs in smooth progression.6.6 Impact loadingAdditional torsional stresses will be generated in a spring, if one end of the spring is suddenly accelerated to a highspeed
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