BS EN 16984-2016 Disc springs Calculation《盘式弹簧 计算》.pdf

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1、BS EN 16984:2016Disc springs CalculationBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS EN 16984:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN 16984:2016.The UK participation in its preparation was entrusted to Technica

2、lCommittee FME/9/3, Springs.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 201

3、6. Published by BSI Standards Limited 2016ISBN 978 0 580 93171 0ICS 21.160Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2016.Amendments/Corrigenda is

4、sued since publicationDate Text affectedBS EN 16984:2016EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16984 November 2016 ICS 21.160 English Version Disc springs - Calculation Rondelles ressorts - Calculs Tellerfedern - Berechnung This European Standard was approved by CEN on 15 August 2016.

5、CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on a

6、pplication to the CEN-CENELEC 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 translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC

7、 Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,

8、Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue M

9、arnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16984:2016 EBS EN 16984:2016EN 16984:2016 (E) 2 Contents Page European foreword . 3 1 Scope 4 2 Normative references 4 3 Terms, definitions, symbols, un

10、its and abbreviated terms . 4 3.1 Terms and definitions . 4 3.2 Symbols, units and abbreviated terms 4 4 Representation. 6 4.1 Single disc spring . 6 4.2 Disc springs stacked in parallel . 6 4.3 Disc springs stacked in series . 6 4.4 Disc spring diagram . 7 5 Design formulae for single disc springs

11、7 5.1 General 7 5.2 Test load . 7 5.3 Deflection factors 8 5.4 Spring load . 8 5.5 Design stresses . 9 5.6 Spring rate 10 5.7 Energy capacity of springs 10 6 Load/deflection curve for a single disc spring 10 7 Stacking of disc springs 11 8 Effect of friction in load/deflection characteristic . 13 9

12、Design stresses 14 10 Types of loading 15 10.1 Static loading and moderate fatigue conditions . 15 10.2 Dynamic loading . 15 Bibliography . 16 BS EN 16984:2016EN 16984:2016 (E) 3 European foreword This document (EN 16984:2016) has been prepared by Technical Committee CEN/TC 407 “Cylindrical helical

13、springs made from round wire and bar - Calculation and design”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by May 2017, and conflicting national standa

14、rds shall be withdrawn at the latest by May 2017. This European Standard has been prepared by the initiative of the Association of the European Spring Federation ESF and is based on the German Standard DIN 2092 “Disc springs Calculation”, which is known and used in many European countries. Attention

15、 is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following count

16、ries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Pol

17、and, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 16984:2016EN 16984:2016 (E) 4 1 Scope This standard specifies design criteria and features of disc springs, whether as single disc springs or as stacks of disc springs. It includes the defini

18、tion of relevant concepts as well as design formulae, and covers the fatigue life of such springs. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited

19、applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 16983:2016, Disc springs - Quality specifications - Dimensions EN ISO 26909, Springs - Vocabulary (ISO 26909) 3 Terms, definitions, symbols, units and abbreviated terms 3.1 Terms and

20、 definitions For the purposes of this document, the terms and definitions given in EN ISO 26909 apply. NOTE Disc springs are annular coned elements that offer resistance to a compressive load applied axially. They may be designed as single disc springs or as disc springs stacked in parallel or in se

21、ries, either singly or in multiples. They may be subjected to both static and fatigue loading, and may have flat bearings. 3.2 Symbols, units and abbreviated terms For the purposes of this document, the following symbols, units and abbreviated terms apply Table 1 Symbols, units and abbreviated terms

22、 Symbol Unit Description Demm Outer diameter of spring Dimm Inner diameter of spring D0mm Diameter of centre of rotation E MPa Modulus of elasticity (see EN 16983:2016) F N Spring load F1, F2, F3. N Spring loads related to spring deflections s1, s2, s3 FcN Design spring load when spring is in the fl

23、attened position Fges N Spring load of springs stacked in parallel, related to spring deflection sgesFges R N Spring load of springs stacked in parallel, allowance being made for friction FtN Test load for length Ltor ltK1, K2, K3, K4Constants (see 5.3) L0mm Length of springs stacked in series or in

24、 parallel, in BS EN 16984:2016EN 16984:2016 (E) 5 Symbol Unit Description the initial position L1, L2, L3. mm Lengths of loaded springs stacked in series or in parallel, related to spring loads F1, F2, F3 Ltmm Test length of springs stacked in series or in parallel Lcmm Design length of springs stac

25、ked in series or in parallel, in the flattened position N Number of cycles to failure R N/mm Spring rate W N mm Energy capacity of spring h0mm Initial cone height of springs without flat bearings, h0= l0 t h0mm Initial cone height of springs with flat bearings, h0= l0 t i Number of disc springs or p

26、ackets stacked in series l0mm Free overall height of spring in its initial position l1, l2, l3. mm Length of loaded spring related to spring loads F1, F2, F3 Ltmm Test length of spring n Number of single disc springs stacked in parallel P Theoretical centre of rotation of disc cross section (see Fig

27、ure 1) s mm Deflection of single disc spring s1, s2, s3. mm Spring deflections related to spring loads F1, F2, F3 sges mm Deflection of springs stacked in series or in parallel, no allowance being made for friction. Recommended maximum value: sges= 0,75 (L0 Lc) t mm Thickness of single disc spring t

28、 mm Reduced thickness of single disc spring with flat bearings (group 3) wM, wRCoefficients of friction (see Table 3) =eiDDRatio of outer to inner diameter Poissons ratio MPa Design stress OM, I, II, III, IVMPa Design stresses at the points designated OM, I, II, III, IV (see Figure 1) oMPa Maximum d

29、esign stress in springs subject to fatigue BS EN 16984:2016EN 16984:2016 (E) 6 Symbol Unit Description loading uMPa Minimum design stress in springs subject to fatigue loading hMPa Fatigue stress related to the deflection of springs subject to fatigue loading OMPa Maximum fatigue stress UMPa Minimum

30、 fatigue stress H= O UMPa Permanent range of fatigue stress V, V mm Lever arms 4 Representation 4.1 Single disc spring a) without flat bearings: b) with flat bearings: group 1 group 3 group 2 Figure 1 Single disc spring (sectional view), including the relevant points of loading 4.2 Disc springs stac

31、ked in parallel The stack consists of n single disc springs stacked in parallel. Figure 2 Packet - Disc springs stacked in parallel 4.3 Disc springs stacked in series The stack consists of i single disc springs stacked in series. BS EN 16984:2016EN 16984:2016 (E) 7 Figure 3 Stack - Disc springs stac

32、ked in series 4.4 Disc spring diagram Figure 4 Example of disc springs stacked in series 5 Design formulae for single disc springs 5.1 General The following formulae apply to single disc springs with or without flat bearings, where 16 0,75, the actual curve will deviate more and more from the design

33、 curve, since the disc springs will be in contact with each other or with the support plate, which results in a steady reduction in the length of the lever arm (see Figure 7). 7 Stacking of disc springs A number of possibilities exist for combining single disc springs or several disc springs stacked

34、 in series and/or in parallel. In the case of single disc springs with constant deflection stacked in parallel, the spring load will be in direct proportion to the number of single disc springs making up the stack (see Figures 8a and 8b). In the case of single disc springs with constant spring load

35、stacked in series, the deflection will be in direct proportion to the number of single disc springs making up the stack (see Figures 8a and 8c). = gesF nF (17) = gess is (18) ( )= +001L il n t (19) In the case of springs with flat bearings, t shall be substituted for t. In the case of packets stacke

36、d in series, the spring load will increase with the number of single disc springs making up each packet, and the deflection, with the number of packets making up the stack (see Figure 8d). BS EN 16984:2016EN 16984:2016 (E) 12 In the case of springs stacked in series, where h0/t approximately 1,25, i

37、t may be assumed that the deflection of the single disc springs will not be uniform, which may cause a failure. Where single disc springs of different thicknesses are stacked in series (see Figure 9a), the load/deflection curve will be progressive. The same applies where an increasing number of sing

38、le disc springs of identical thickness are combined in the packets making up the stack (see Figure 9b). The permissible stresses in the elements numbered 1 and 2, however, shall be taken into account. Note that the information given in Figures 8 and 9 does not account for friction. Figure 8a Figure

39、8b Figure 8c Figure 8d Figure 8 Variations in load/deflection curves as a function of disc spring stacking BS EN 16984:2016EN 16984:2016 (E) 13 Figure 9a Figure 9b Figure 9 Progressive load/deflection curves for disc springs with different thicknesses or stackings 8 Effect of friction in load/deflec

40、tion characteristic When designing springs, friction shall be accounted for. The associated load component is a function of the number of single disc springs or elements making up a stack of springs. In this regard, surface finish and lubrication are also of relevance. Frictional loads act between t

41、he conical contact surfaces of the individual springs (factor wM) and the contact surfaces of the flat plates between the spring is compressed (factor wR). Such loads have the effect of increasing the spring load when the spring is loaded, and decreasing it when the load is removed. The load/deflect

42、ion characteristic shall be calculated using the following formula: ( )= 11gesRRnFFwn w(20) where - indicates the loading + indicates the unloading BS EN 16984:2016EN 16984:2016 (E) 14 Table 3 Values of inter-surface friction (factor wM) and edge friction (factor wR) (does not apply to shot peened s

43、prings) Dimensional series as in EN 16983:2016 wMwRA 0,005 to 0,03 0,03 to 0,05 B 0,003 to 0,02 0,02 to 0,04 C 0,002 to 0,015 0,01 to 0,03 Formula (20) also accounts for the frictional behaviour of a single disc spring. Within permissible tolerances, the actual spring will deviate from the geometric

44、ally ideal form. In the case of springs stacked in parallel, such inevitable deviation results in an actual load/deflection curve that is different from the theoretical curve (and increasingly different as the number of packets making up the stack increases), particularly in the lower range of the c

45、urve. 9 Design stresses Since there are residual stresses in the spring as a result of the manufacturing process used, the results obtained from Formulae (10) to (14) do not reflect the actual values involved, but rather any nominal values. Thus, all information relating to stress in the present sta

46、ndard and in EN 16983:2016, Tables 5 to 7, represent these nominal values. An estimate of the permissible free overall height of the spring, l0, may be based on a determination of the design stress OM, which should be about equal to the tensile strength, Rm, of the material used (for materials as in

47、 EN 16983:2016, max. 1 600 MPa). The most important parameter for springs subject to fatigue loading is the calculated tensile stress on the bottom side of a single disc spring. The point most vulnerable to fatigue failure will be either the lower inner edge, point II, or the lower outer edge, point

48、 III (see Figure 10), depending on the ratios De/Di= , h0/t and s/h0. This is illustrated in Figure 10, and applies to springs with or without flat bearings. BS EN 16984:2016EN 16984:2016 (E) 15 Key 1 Point III 2 Point II or III 3 Point II NOTE In the case of springs with flat bearings, K4 h0/t shal

49、l be substituted for h0/t. Figure 10 Relevant points of loading for springs subject to fatigue loading Since the ratio s/h0is a factor of influence with regard to the magnitude of tensile stress at points II and III, it is recommended, for the zone between these points, that IIand IIIbe determined in accordance with the formulae given in 5.5. Graphical representations of the fatigue life of springs are given in EN 16983:2016. 10 Types of loading 10.1 Static loading and moderate fatigue