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1、Reference number ISO/TR 13989-1:2000(E) ISO 2000 TECHNICAL REPORT ISO/TR 13989-1 First edition 2000-03-15 Calculation of scuffing load capacity of cylindrical, bevel and hypoid gears Part 1: Flash temperature method Calcul de la capacit de charge au grippage des engrenages cylindriques, coniques et
2、hypodes Partie 1: Mthode de la temprature-clair ISO/TR 13989-1:2000(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and insta
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5、lease inform the Central Secretariat at the address given below. ISO 2000 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writ
6、ing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 ? CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 734 10 79 E-mail copyrightiso.ch Web www.iso.ch Printed in Switzerland ii ISO 2000 All rights reserved ISO/TR 1398
7、9-1:2000(E) ISO 2000 All rights reservediii ContentsPage Foreword.iv Introduction.v 1Scope 1 2Normative references1 3Terms, definitions, symbols and units.1 3.1Terms and definitions .1 3.2Symbols and units.1 4Scuffing and wear6 4.1Occurrence of scuffing and wear.6 4.2Transition diagram.6 4.3Friction
8、 at incipient scuffing.8 5Basic formulae.8 5.1Contact temperature8 5.2Flash temperature formula9 5.3Transverse unit load10 5.4Distribution of overall bulk temperatures .11 5.5Rough approximation of a bulk temperature12 6Coefficient of friction.12 6.1Mean coefficient of friction, method A.13 6.2Mean
9、coefficient of friction, method B 13 6.3Mean coefficient of friction, method C 13 7Parameter on the line of action 14 8Approach factor .16 9Load sharing factor .17 9.1Buttressing factor17 9.2Spur gears with unmodified profiles .18 9.3Spur gears with profile modification .19 9.4Narrow helical gears w
10、ith unmodified profiles.20 9.5Narrow helical gears with profile modification.20 9.6Wide helical gears with unmodified profiles.21 9.7Wide helical gears with profile modification.21 9.8Narrow bevel gears22 9.9Wide bevel gears23 10Scuffing temperature and safety24 10.1Scuffing temperature.24 10.2Struc
11、tural factor.24 10.3Contact exposure time25 10.4Scuffing temperature in gear tests.26 10.5Safety range .26 Annexe A (informative) Flash temperature formula presentation.28 Annexe B (informative) Optimal profile modification 35 Bibliography37 ISO/TR 13989-1:2000(E) iv ISO 2000 All rights reserved For
12、eword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a tech
13、nical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
14、 electrotechnical standardization. The main task of technical committees is to prepare International Standards, but in exceptional circumstances a technical committee may propose the publication of a Technical Report of one of the following types: ?type 1, when the required support cannot be obtaine
15、d for the publication of an International Standard, despite repeated efforts; ?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 agreement on an International Standard; ?type 3, when a technical committ
16、ee 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 publication, to decide whether they can be transformed into International Sta
17、ndards. Technical Reports of type 3 do not necessarily have to be reviewed until the data they provide are considered to be no longer valid or useful. Technical Reports are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. Attention is drawn to the possibility that some o
18、f the elements of this part of ISO/TR 13989 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO/TR 13989-1, which is a Technical Report of type 2, was prepared by Technical Committee ISO/TC 60,Gears, Subcommittee SC 2,Gear capacit
19、y calculation. ThisdocumentisbeingissuedintheTechnicalReport(type 2)seriesofpublications(accordingto subclause G.3.2.2 of Part 1 of the ISO/IEC Directives, 1995) as a “prospective standard for provisional application” in the field of scuffing load capacity of gears because there is an urgent need fo
20、r guidance on how standards in this field should be used to meet an identified need. In 1975, two methods to evaluate the risk of scuffing were documented to be studied by ISO/TC 60. It was agreed that after a period of experience one method shall be selected. Since the subject is still under techni
21、cal development and there is a future possibility of an agreement on an International Standard, the publication of a type 2 Technical Report was proposed. This document is not to be regarded as an “International Standard”. It is proposed for provisional application so that information and experience
22、 of its use in practice may be gathered. Comments on the content of this document should be sent to the ISO Central Secretariat. A review of this Technical Report (type 2) will be carried out not later than three years after its publication with the options of: extension for another three years; con
23、version into an International Standard; or withdrawal. ISO/TR 13989 consists of the following parts, under the general titleCalculation of scuffing load capacity of cylindrical, bevel and hypoid gears: ?Part 1: Flash temperature method ?Part 2: Integral temperature method Annexes A and B of this par
24、t of ISO 13989 are for information only. -,-,- ISO/TR 13989-1:2000(E) ISO 2000 All rights reservedv Introduction Since 1990 the flash temperature method, presented in this part of ISO/TR 13989, was enriched with research for short exposure times, consideration of transition diagrams, new approximati
25、ons for the coefficient of friction, and completely renewed load sharing factors. In 1991 Prof. Blok contributed an extension of the flash temperature formula which made it directly applicable to hypoid gears. The integral temperature, presented in ISO/TR 13989-2, averages the flash temperature and
26、supplements empirical influence factors to the hidden load sharing factor. The resulting value approximates the maximum contact temperature, thus yielding about the same assessment of scuffing risk as the flash temperature method of this part of ISO/TR 13989. The integral temperature method is less
27、sensitive for those cases where there are local temperature peaks, usually in gearsets that have low contact ratio or contact near the base circle or other sensitive geometries. The risk of scuffing damage varies with the properties of gear materials, the lubricant used, the surface roughness of too
28、th flanks, the sliding velocities and the load. In contrast to the relatively long time of development of fatigue damage, one single momentary overload can initiate scuffing damage of such severity that affected gears may no longer be used. According to Blok 121314151617, high contact temperatures o
29、f lubricant and tooth surfaces at the instantaneous contact position may effect a break-down of the lubricant film at the contact interface. The interfacial contact temperature is conceived as the sum of two components: ?the interfacial bulk temperature of the moving interface, which, if varying, do
30、es so only comparatively slowly. For evaluating this component, it may be suitably averaged from the two overall bulk temperatures of the two rubbing teeth. The latter two bulk temperatures follow from the thermal network theory 18. ?the rapidly fluctuating flash temperature of the moving faces in c
31、ontact. Special attention has to be paid to the coefficient of friction. A common practice is the use of a coefficient of friction valid for regular working conditions, although it may be stated that at incipient scuffing the coefficient of friction has significantly higher values. The complex relat
32、ionship between mechanical, hydrodynamical, thermodynamical and chemical phenomena was the objective of extensive research and experiments, which may induce various empirical influence factors. A direct suppletion of empirical influence factors may enforce the related functional factors in the main
33、formula to be fixated to average values. However, correct treatment of functional factors (e.g. coefficient of friction, load sharing factor, thermal contact coefficient) keeps the main formula intact, in confirmation with the experiments and practice. Next to the maximum contact temperature, the pr
34、ogress of the contact temperature along the path of contact provides necessary information to the gear design. TECHNICAL REPORTISO/TR 13989-1:2000(E) ISO 2000 All rights reserved1 Calculation of scuffing load capacity of cylindrical, bevel and hypoid gears Part 1: Flash temperature method 1Scope Thi
35、s part of ISO/TR 13989 specifies methods and formulae for evaluating the risk of scuffing, based on Bloks contact temperature concept. The fundamental concept according to Blok is applicable to all machine elements with moving contact zones. The flash temperature formulae are valid for a band-shaped
36、 or approximately band-shaped Hertzian contact zone and working conditions characterized by sufficiently high Pclet numbers. 2Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO/TR 13989. For dated
37、 references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO/TR 13989 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated
38、 references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 1122-1:1998,Vocabulary of gear terms Part 1: Definitions related to geometry. ISO 6336-1:1996,Calculation of load capacity of spur
39、and helical gears Part 1: Basic principles, introduction and general influence factors. ISO 10300-1:1),Calculation of load capacity of bevel gears Part 1: Introduction and general influence factors. ISO 10825:1995,Gears Wear and damage to gear teeth Terminology. 3Terms, definitions, symbols and unit
40、s 3.1Terms and definitions For the purposes of this part of ISO/TR 13989, the terms and definitions given in ISO 1122-1 and ISO 10825 apply. 3.2Symbols and units The symbols used in this part of ISO/TR 13989 are given in Table 1. The units of length metre, millimetre and micrometre are chosen in acc
41、ordance with common practice. To achieve a “coherent“ system, the units for BM, c?, XMare adapted to the mixed application of metre and millimetre or millimetre and micrometre. 1)To be published. ISO/TR 13989-1:2000(E) 2 ISO 2000 All rights reserved Table 1 Symbols and units SymbolDescriptionUnitRef
42、erence acentre distancemmEq. (A.5) bfacewidth, smaller value for pinion or wheelammEq. (11) beffeffective facewidthmmEq. (12) bHsemi-width of Hertzian contact bandmmEq. (3) BMthermal contact coefficientN/(mm?m?s?K)Eq (A.13) BM1thermal contact coefficient of pinionN/(mm?m?s?K)Eq. (3) BM2thermal conta
43、ct coefficient of wheelN/(mm?m?s?K)Eq. (3) Ca1tip relief of pinion?mEq. (48) Ca2tip relief of wheel?mEq. (46) Ceffoptimal tip relief?mEq. (46) Ceq1equivalent tip relief of pinion?mEq. (B.2) Ceq2equivalent tip relief of wheel?mEq. (B.3) Cf1root relief of pinion?mEq. (B.3) Cf2root relief of wheel?mEq.
44、 (B.2) cM1specific heat per unit mass of pinionJ/(kg?K)Eq. (9) cM2specific heat per unit mass of wheelJ/(kg?K)Eq. (10) c?mesh stiffnessN/(mm?m)Eq. (B.1) d1reference diameter of pinionmmEq. (34) d2reference diameter of wheelmmEq. (35) da1tip diameter of pinionmmEq. (34) da2tip diameter of wheelmmEq.
45、(35) E1modulus of elasticity of pinionN/mm2Eq. (A.10) E2modulus of elasticity of wheelN/mm2Eq. (A.10) Erreduced modulus of elasticityN/mm2Eq. (A.9) Fexexternal axial forceNEq. (18) Fnnormal load in wear testNFig. 1 Ftnominal tangential forceNEq. (11) H1auxiliary dimensionmmEq. (B.3) H2auxiliary dime
46、nsionmmEq. (B.2) ham1tip height in mean cone of pinionmmEq. (43) ham2tip height in mean cone of wheelmmEq. (44) -,-,- ISO/TR 13989-1:2000(E) ISO 2000 All rights reserved3 Table 1 Symbols and units(continued) SymbolDescriptionUnitReference KAapplication factorEq. (11) KB?transverse load factor (scuff
47、ing)Eq. (11) KB?face load factor (scuffing)Eq. (11) KH?transverse load factor (contact stress)Eq. (15) KH?face load factor (contact stress)Eq. (14) Kmpmultiple path factorEq. (11) Kvdynamic factorEq. (11) mnnormal modulemmEq. (B.2) n1revolutions per minute of pinionr/minEq. (5) npnumber of mesh cont
48、actsEq. (16) Pe1Pclet number of pinion materialEq. (9) Pe2Pclet number of wheel materialEq. (10) Qquality gradeEq. (57) Ra1tooth flank surface roughness of pinion?mEq. (28) Ra2tooth flank surface roughness of wheel?mEq. (28) Rmcone distance of mean conemmEq. (A.16) rm1reference radius in mean cone o
49、f pinionmmEq. (43) rm2reference radius in mean cone of wheelmmEq. (44) SBsafety factor for scuffingEq. (100) SFZGload stage (in FZG test)Eq. (99) t1contact exposure time of pinion?sEq. (95) t2contact exposure time of wheel?sEq. (96) tccontact exposure time at bend of curve?sEq. (97) tmaxlongest contact exposure time?sEq. (95) ugear ratioEq. (A.6) uvvirtual ratioEq. (B.6) vgsliding velocitym/sFig. 1 vg1tangent