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1、BRITISH STANDARD BS ISO/TR 10495:1997 Cylindrical gears Calculation of service life under variable load Conditions for cylindrical gears in accordance with ISO 6336 ICS 21.200 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1
2、997 This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 May 1998 BSI 04-1999 ISBN 0 580 29826 4 National foreword This British Standard reproduces verbatim ISO/TR 10495:1
3、997 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee MCE/5, Gears, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interp
4、retation, 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 this committee can be obtained on request to its secretary. Cross-references The British Standards whic
5、h 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 Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does no
6、t 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 confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside f
7、ront cover, pages i and ii, the ISO/TR title page, pages ii to iv, pages 1 to 14, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments i
8、ssued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 BSI 04-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO/TR 104951 Licensed Copy: sheffieldun she
9、ffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
10、BS ISO/TR 10495:1997 ii BSI 04-1999 Contents Page Forewordiii 1Scope1 2Normative references1 3Definitions, symbols, quantities and units1 4Introduction1 5General calculation of service life, Method I7 6Calculation of service strength on the basis of single-stage strength; calculation according to IS
11、O 6336, Method II7 7Random reverse torques10 8Reference values for application factor, KA11 Annex A (informative) Guide values for the application factor, KA12 Annex B (informative) BibliographyInside back cover Figure 1 Torque spectrum (class number = 258)4 Figure 2 Example for a cumulative stress
12、spectrum5 Figure 3 Measured cumulative tooth root stress spectra for different teeth of one wheel5 Figure 4 Cumulative contact stress spectrum with S-N curve6 Figure 5 Torque spectrum and associated stress spectrum with S-N curve8 Figure 6 Accumulation of damage9 Figure 7 Flow chart for the determin
13、ation of the calculated safety factor for a given load spectrum11 Table 1 Symbols used within ISO TR 104952 Table 2 Example (see Figure 1): Classes 111 type 2, when the subject is still under technical development or where for any other reason there is the future but not immediate possibility of an
14、agreement on an International Standard; type 3, when a technical committee has collected data of a different kind from that which is normally published as an International Standard (“state of the art”, for example). Technical Reports of types 1 and 2 are subject to review within three years of publi
15、cation, to decide whether they can be transformed into International Standards. Technical Reports of type 3 do not necessarily have to be reviewed until data they provide are considered to be no longer valid or useful. ISO/TR 10495, which is a Technical Report of type 2, was prepared by Technical Co
16、mmittee ISO/TC 60, Gears, Subcommittee SC 2, Gear capacity calculation. Annex A and Annex B of this Technical Report are for information only. Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, n
17、a, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 BSI 04-19991 1 Scope This Technical Report is concerned with the calculation of service life (or safety factors for a required life) of gears subject to variable loading. Clauses 4 and 5 give a general discussion
18、of the subject; clauses 6 to 8 present a method which may be conveniently applied at the design stage. Whilst the method is presented in terms of ISO 6336, it is equally applicable to other gear stress calculations (e.g BS 436, DIN 3990, NF E23-015). 2 Normative references The following standards co
19、ntain provisions which, through reference in this text, constitute provisions of this Technical Report. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this Technical Report are encouraged to investigate the pos
20、sibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 701:1976, International gear rotation Symbols for geometrical data. ISO 1122-1:1983, Glossary of gear terms Part 1: Geometrical de
21、finitions. ISO 6336-1:1996, Calculation of load capacity of spur and helical gears Part 1: Basic principles, introduction and general influence factors. ISO 6336-2:1996, Calculation of load capacity of spur and helical gears Part 2: Calculation of surface durability (pitting). ISO 6336-3:1996, Calcu
22、lation of load capacity of spur and helical gears Part 3: Calculation of tooth bending strength. ISO 6336-5:1996, Calculation of load capacity of spur and helical gears Part 5: Strength and quality of material. 3 Definitions, symbols, quantities and units For the purposes of ISO TR 10495, the defini
23、tions given in ISO 1122-1 apply. Symbols are based on those given in ISO 701. Only symbols for quantities used in ISO TR 10495 are given in Table 1. 4 Introduction 4.1 Determination of load and stress spectra Variable loads resulting from a working process, starting process or from operation at or n
24、ear a critical speed will cause varying stresses at the gear teeth of a drive system. The magnitude and frequency of these loads depend upon the driven machine(s), the driver(s) or motor(s) and the mass elastic properties of the system. These variable loads (stresses) may be determined by one or mor
25、e of the procedures listed below: a) Experimental measurement of the operating loads at the machine in question; b) Estimation of the spectrum, if this is known, for a similar machine with similar operating mode; c) Calculation, using known external excitation and a mass elastic simulation of the dr
26、ive system. NOTESpecific data, relevant for the method by which the load or torque measurements are performed, should be marked at the registered results. To obtain the spectra, the range of the measured (evaluated) loads is divided into classes. A widely used number of classes is 64. The cycle coun
27、t for the load class corresponding to the load value for the highest loaded tooth is incremented at every load repetition. Table 2 shows as an example how to apply the torque classes defined in Figure 1 to specific torque levels and correlated numbers of cycles. Licensed Copy: sheffieldun sheffieldu
28、n, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 2 BSI 04-1999 Table 1 Symbols used within ISO TR 10495 SymbolQuantityUnit bFacewidthmm d1Reference diameter of pinionmm eInclination of S-N curve- - iClass- - IClass interval- - KAApplication factor- - KF!Tran
29、sverse load distribution factor (bending stress)- - KF“Face load distribution factor (bending stress)- - KH!Transverse load distribution factor (contact stress)- - KH“Face load distribution factor (contact stress)- - KvDynamic factor- - mnNormal modulemm niNumber of cycles at ith stress level (numbe
30、r of counts in class i)- - nINumber of cycles at class interval level I- - NINumber of cycles to failure at class interval level I- - NLNumber of cycles to failure- - SSafety factor for stress- - SF limSafety factor for bending stress (min.)- - SH limSafety factor for contact stress (min.)- - TiTorq
31、ue classNm TIPinion torque at top of class intervalNm uGear ratio- - UMiner sum- - UIIndividual damage part of class interval- - YFTooth form factor- - YNTTooth root stress life factor for standard test conditions- - YR rel TRelative surface condition factor (root)- - YSStress correction factor- - Y
32、STStress correction factor for the dimension of the standard test gears- - YXSize factor (bending stress)- - Y“Helix angle factor (bending stress)- - Y$ rel TRelative notch sensitivity factor- - ZB,DSingle pair tooth contact factor for pinion or gear- - ZEElasticity factor(N/mm2)1/2 ZHZone factor- -
33、 ZLLubricant influence factor- - ZNTContact stress life factor for standard test conditions- - ZRRoughness factor- - ZvSpeed factor- - ZWHardness ratio factor- - Z“Helix angle factor (contact stress)- - Z(Contact ratio factor (contact stress)- - BF limNominal stress number (bending)N/mm2 BFITooth ro
34、ot stress at class interval IN/mm2 BFPPermissible tooth root stressN/mm2 BH limAllowable stress number (contact)N/mm2 BHIContact stress at class interval IN/mm2 BHONominal contact stressN/mm2 BHPPermissible contact stressN/mm2 BIStress at class interval IN/mm2 BlimAllowable stressN/mm2 BPPermissible
35、 stressN/mm2 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 BSI 04-19993 Table 2 Example (see Figure 1): Classes 111 b) Material fatigue properties; c) A damage accumulation method. The stress spectrum is discussed in c
36、lause 6.1. Strength values based on material fatigue properties are chosen from applicable S-N curves. Many specimens must be tested by stressing them repeatedly at one stress level until failure occurs. This gives, after a statistical interpretation for a specific probability, a failure cycle numbe
37、r characteristic of this stress level. Repeating the procedure at different stress levels leads to an S-N curve. An example of a cumulative stress spectrum is given in Figure 2. Figure 3 shows measured cumulative stress spectra for tooth root stress. Figure 4 shows a cumulative contact stress spectr
38、um with an S-N curve for specific material fatigue properties. Torque class, Ti, NmNumber of cycles, ni 440 # T111 444n111= 2 338 444 # T112 448n112= 4 318 Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 4 BSI 04-1999 Ti
39、 in Nm+ 0.+ 4+ 4.+ 8+ 8.+ 12+ 12.+ 16+ 16.+ 20+ 20.+ 24 0,00 24,00 48,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 72,00 96,00 120,00 0 0 0 0 0 706 0 0 3 469 0 0 3 081 0 0 5 109 0 0 32 144,00 168,00 192,00 1 2 45 2 0 350 438 0 212 381 0 616 756 0 16 903 1 0 216,00 240,00 264,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0
40、 19 0 0 2 108 288,00 312,00 336,00 2 072 0 0 3 933 0 0 4 257 0 0 6 0 0 2 0 0 3 0 0 360,00 384,00 408,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 432,00 456,00 480,00 26 239 932 72 477 90 2 338a 2 553 420 4 318a 3 216 1 913 3 665 5 576 2 877 1 824 2 109 2 891 504,00 528,00 552,00 1 255 651 0 449 518 0 67
41、23 8 791 1 24 745 0 127 2 166 0 520 576,00 600,00 624,00 751 0 0 713 0 0 295 0 0 42 0 0 0 0 0 0 0 3 648,00 672,00 696,00 218 0 0 187 0 0 329 0 0 469 0 0 34 0 0 0 0 0 720,00 744,00 768,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 792,00 816,00 840,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 864,00 888,00 912,00
42、 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 936,00 960,00 984,00 1 008,00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 a example presented in Table 2 Figure 1 Torque spectrum (class number = 258) Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI B
43、S ISO/TR 10495:1997 BSI 04-19995 Figure 2 Example for a cumulative stress spectrum Figure 3 Measured cumulative tooth root stress spectra for different teeth of one wheel Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 6
44、 BSI 04-1999 Linear, non-linear and relative methods are used. The literature presented in Annex B gives a general account of the present state and application of damage accumulation. 4.3 Palmgren-Miner rule The Palmgren-Miner rule besides other rules or modifications is a widely used linear damage
45、accumulation method. It is assumed that the damaging effect of each stress repetition at a given stress level is equal, which means the first stress cycle at a given stress level is as damaging as the last. The Palmgren-Miner rule operates on the hypothesis that the portion of useful fatigue life us
46、ed by a number of repeated stress cycles at a particular stress is equal to the ratio of the total number of cycles during the fatigue life at a particular stress level according to the S-N curve established for the material. For example, if a part is stressed for 3 000 cycles at a stress level whic
47、h would cause failure in 1 00 000 cycles, 3 % of the fatigue life would be expended. Repeated stress at another stress level would consume another similarly calculated portion of the total fatigue life. NOTEThe used material fatigue characteristics and endurance data should be related to a specific
48、and required failure probability, e.g. 1 %, 5 % or 10 %. NOTEThe representation of the cumulative stress spectrum entirely below the S-N curve does not imply that the part will survive the total accumulative number of stress cycles. This information can be gained from a presentation as shown in Figu
49、re 6. Figure 4 Cumulative contact stress spectrum with S-N curve Licensed Copy: sheffieldun sheffieldun, na, Sun Nov 26 06:15:01 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS ISO/TR 10495:1997 BSI 04-19997 When 100 % of the fatigue life is expended in this manner, the part could be expected to fail. The order in which each of these individual stress cycles is applied is not considered significant in Palmgren-Miner analysis. Failure could be expected when: If there is an endurance limit (upper, horizonta