1、BSI Standards PublicationBS ISO 10300-2:2014Calculation of load capacity ofbevel gearsPart 2: Calculation of surface durability(pitting)BS ISO 10300-2:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 10300-2:2014.It supersedes BS ISO 10300-2:2001 which is w
2、ithdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee MCE/5/-/13, Bevel gears.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
3、are responsible for its correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 71822 9ICS 21.200Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStan
4、dards Policy and Strategy Committee on 31 March 2014.Amendments issued since publicationDate Text affectedBS ISO 10300-2:2014 ISO 2014Calculation of load capacity of bevel gears Part 2: Calculation of surface durability (pitting)Calcul de la capacit de charge des engrenages coniques Partie 2: Calcul
5、 de la rsistance la pression superficielle (formation des piqres)INTERNATIONAL STANDARDISO10300-2Second edition2014-04-01Reference numberISO 10300-2:2014(E)BS ISO 10300-2:2014ISO 10300-2:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise
6、specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
7、or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 10300-2:2014ISO 10300-2:2014(E) ISO 2014 All rights reserved iiiContents PageForewo
8、rd ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Symbols, units and abbreviated terms 25 Pitting damage General aspects 35.1 Acceptable versus unacceptable pitting 35.2 Assessment requirements . 35.3 General rating procedure . 46 Gear flank rating formulae Method B1
9、 46.1 Contact stress formula 46.2 Permissible contact stress . 66.3 Calculated safety factor for contact stress . 66.4 Contact stress factors 66.5 Permissible contact stress factors . 107 Gear flank rating formulae Method B2 .137.1 Contact stress formula. 137.2 Permissible contact stress 147.3 Calcu
10、lated safety factor for contact stress 147.4 Contact stress factors . 158 Factors for contact stress and permissible contact stress common for method B1 and method B2 208.1 Elasticity factor, ZE.208.2 Lubricant film influence factors, ZL, Zv, ZR208.3 Work hardening factor, ZW248.4 Life factor, ZNT25
11、Annex A (informative) Bevel slip factor ZS Method B1 28Bibliography .30BS ISO 10300-2:2014ISO 10300-2:2014(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is n
12、ormally carried out through ISO technical committees. Each member body interested in a subject for which a technical 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 i
13、n the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular
14、the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directivesAttention is drawn to the possibility that some of the elements of this document
15、may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received. www.iso.org/patents
16、Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in
17、 the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 60, Gears, Subcommittee SC 2, Gear capacity calculation.This second edition cancels and replaces the first edition (ISO 10300-2:2001), which has bee
18、n technically revised.ISO 10300 consists of the following parts, under the general title Calculation of load capacity of bevel gears: Part 1: Introduction and general influence factors Part 2: Calculation of surface durability (pitting) Part 3: Calculation of tooth root strengthiv ISO 2014 All right
19、s reservedBS ISO 10300-2:2014ISO 10300-2:2014(E)IntroductionWhen ISO 10300:2001 (all parts, withdrawn) became due for (its first) revision, the opportunity was taken to include hypoid gears, since previously the series only allowed for calculating the load capacity of bevel gears without offset axes
20、. The former structure is retained, i.e. three parts of the ISO 10300 series, together with ISO 6336-5, and it is intended to establish general principles and procedures for rating of bevel gears. Moreover, ISO 10300 (all parts) is designed to facilitate the application of future knowledge and devel
21、opments, as well as the exchange of information gained from experience.In view of the decision for ISO 10300 (all parts) to cover hypoid gears also, it was agreed to include a separate clause: “Gear flank rating formulae Method B2” in this part of ISO 10300, while the former method B was renamed met
22、hod B1. So, it became necessary to present a new, clearer structure of the three parts, which is illustrated in ISO 10300-1:2014, Figure 1. Note, ISO 10300 (all parts) gives no preferences in terms of when to use method B1 and when method B2.This part of ISO 10300 deals with the failure of gear teet
23、h by pitting, a fatigue phenomenon. Two varieties of pitting are recognized, initial and destructive pitting.In applications employing low hardness steel or through hardened steel, initial pitting frequently occurs during early use and is not deemed serious. Initial pitting is characterized by small
24、 pits which do not extend over the entire face width or profile depth of the affected tooth. The degree of acceptability of initial pitting varies widely, depending on the gear application. Initial pitting occurs in localized overstressed areas, and tends to redistribute the load by progressively re
25、moving high contact spots. Generally, when the load has been redistributed, the pitting stops.In applications employing high hardness steel and case carburized steel, the variety of pitting that occurs is usually destructive. The formulae for pitting resistance given in this part of ISO 10300 are in
26、tended to assist in the design of bevel gears which stay free from destructive pitting during their design lives (for additional information, see ISO/TR 228494).The basic formulae, first developed by Hertz for the contact pressure between two curved surfaces, have been modified to consider the follo
27、wing four items: the load sharing between adjacent teeth, the position of the centre of pressure on the tooth, the shape of the instantaneous area of contact, and the load concentration resulting from manufacturing uncertainties. The Hertzian contact pressure serves as the theory for the assessment
28、of surface durability with respect to pitting. Although all premises for a gear mesh are not satisfied by Hertzian relations, their use can be justified by the fact that, for a gear material, the limits of the Hertzian pressure are determined on the basis of running tests with gears, which include t
29、he additional influences in the analysis of the limit values. Therefore, if the reference is within the application range, Hertzian pressure can be used to convert test gear data to gears of various types and sizes.NOTE Contrary to cylindrical gears, where the contact is usually linear, bevel gears
30、are generally manufactured with profile and lengthwise crowning: i.e. the tooth flanks are curved on all sides and the contact develops an elliptical pressure surface. This is taken into consideration when determining the load factors by the fact that the rectangular zone of action (in the case of s
31、pur and helical gears) is replaced by an inscribed parallelogram for method B1 and an inscribed ellipse for method B2 (see Annex A for method B1 and Annex B for method B2). The conditions for bevel gears, different from cylindrical gears in their contact, are thus taken into consideration by the lon
32、gitudinal and transverse load distribution factors. ISO 2014 All rights reserved vBS ISO 10300-2:2014BS ISO 10300-2:2014Calculation of load capacity of bevel gears Part 2: Calculation of surface durability (pitting)1 ScopeThis part of ISO 10300 specifies the basic formulae for use in the determinati
33、on of the surface load capacity of straight and helical (skew), Zerol and spiral bevel gears including hypoid gears, and comprises all the influences on surface durability for which quantitative assessments can be made. This part of ISO 10300 is applicable to oil lubricated bevel gears, as long as s
34、ufficient lubricant is present in the mesh at all times.The formulae in this part of ISO 10300 are based on virtual cylindrical gears and restricted to bevel gears whose virtual cylindrical gears have transverse contact ratios of v45, for effective pressure angles e 30 and/or for large face widths b
35、 13 mmn, the calculated results of ISO 10300 should be confirmed by experience.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable to its application. For dated references, only the edition cited applies. For undated r
36、eferences, the latest edition of the referenced document (including any amendments) applies.ISO 1122-1, Vocabulary of gear terms Part 1: Definitions related to geometryISO 6336-5, Calculation of load capacity of spur and helical gears Part 5: Strength and quality of materialsISO 10300-1:2014, Calcul
37、ation of load capacity of bevel gears Part 1: Introduction and general influence factorsISO 10300-3, Calculation of load capacity of bevel gears Part 3: Calculation of tooth root strengthISO 23509, Bevel and hypoid gear geometry3 Terms and definitionsFor the purposes of this document, the terms and
38、definitions given in ISO 1122-1 and ISO 23509 (geometrical gear terms) and the following apply.3.1pittingmaterial fatigue phenomenon of two meshing surfaces under loadINTERNATIONAL STANDARD ISO 10300-2:2014(E) ISO 2014 All rights reserved 1BS ISO 10300-2:2014ISO 10300-2:2014(E)3.2nominal contact str
39、essH0contact stress calculated on the basis of the Hertzian theory at the critical point of load application for error-free gears loaded by a constant nominal torque3.3contact stressHdeterminant contact stress at the critical point of load application including the load factors which consider static
40、 and dynamic loads and load distribution3.4allowable stress numberH,limmaximum contact stress of standardized test gears and determined at standardized operating conditions, as specified in ISO 6336-53.5permissible contact stressHPmaximum contact stress of the evaluated gear set including all influe
41、nce factors4 Symbols, units and abbreviated termsFor the purposes of this document, the symbols and units given in ISO 10300-1:2014, Table 1 and Table 2, as well as the following abbreviated terms, apply (see ISO 6336-5).Table 1 Abbreviated termsAbbreviated term Material TypeStNormalized low carbon
42、steels/cast steelsWrought normalized low carbon steelsSt (cast) Cast steelsGTS (perl.)Cast iron materialsBlack malleable cast iron (perlitic struc-ture)GGG (perl., bai., ferr.)Nodular cast iron (perlitic, bainitic, ferritic structure)GG Grey cast ironV Through hardened wrought steels Carbon steels,
43、alloy steelsV (cast) Through hardened cast steels Carbon steels, alloy steelsEh Case-hardened wrought steelsIFFlame or induction hardened wrought or cast steelsNT (nitr.)Nitrided wrought steels/nitriding steels/through hardening steels, nitridedNitriding steelsNV (nitr.) Through hardening steelsNV (
44、nitrocar.) Wrought steels, nitrocarburized Through hardening steels2 ISO 2014 All rights reservedBS ISO 10300-2:2014ISO 10300-2:2014(E)5 Pitting damage General aspects5.1 Acceptable versus unacceptable pittingWhen limits of the surface durability of the meshing flanks are exceeded, particles break o
45、ut of the flank, thus leaving pits. The extent, to which such pits may be tolerated, in terms of their size and number, varies within wide limits which depend largely on the field of application. In some fields, extensive pitting is acceptable; in others, no pitting is acceptable. The descriptions i
46、n 5.2 and 5.3 are relevant to average working conditions and give guidelines to distinguish between initial and destructive, and acceptable and unacceptable, pitting varieties.A linear or progressive increase in the total area of pits (linear or progressive pitting) is generally considered to be una
47、cceptable. However, it is possible that the effective tooth bearing area is enlarged by initial pitting, and the rate of pit generation subsequently decreases (degressive pitting), or even ceases (arrested pitting), and then may be considered tolerable. Nevertheless, where there is dispute over the
48、acceptability of pitting the next subclause shall be determinant.5.2 Assessment requirementsPitting involving the formation of pits which increase linearly or progressively with time under unchanged service conditions shall be unacceptable. Damage assessment shall include the entire active area of a
49、ll the tooth flanks. The number and size of newly developed pits in unhardened tooth flanks shall be taken into consideration. Pits are frequently formed on just one, or only a few, of the surface hardened gear tooth flanks. In such circumstances, assessment shall be centred on the flanks actually pitted.Teeth suspected of being especially at risk should be marked for critical examination if a quantitative evaluation is required.In special cases, it is possible that a first, rough assessment can be based on considerations
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