BS ISO BRITISH STANDARD 9085:2002 Calculation of load capacity of spur and helical gears Application for industrial gears Confirmed February 2012 ICS 21.200 BSi NO COPYING WITHOUT BSI PERMISSIONEXCEPT AS PERMITTED BY COPYRIGHT LAW BS ISO 9085:2002 National foreword This British Standard reproduces verbatim IS0 9085:2002 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 interpretation, 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 which 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 not 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. This British Standard, having been prepared under the Summary of pages direction of the Engineering This document comprises a front cover, an inside front cover, the IsO title page, Sector Policy and Strategy Committee, was published pages i to vi, pages 1 to 57 and a back cover. under the authority of the The BSI copyright date displayed in this document indicates when the Standards Policy and Strategy Committee on 25March 2002 document was last issued. Amendments issued sincepublication Amd. No. Date Comments C BSI 25 March 2002 ISBN0580392317 ISO INTERNATIONAL STANDARD 9085 First edition 2002-02-01 Calculation of load capacity of spur and helical gears Application for industrial gears Calculde la capacite de charge des engrenages a denture droite et helicoidaleApplicationaux engrenages industriels Reference number ISO 9085:2002(E) ISO ISO9085:2002(E) = ISO9085:2002(E) Contents Page Foreword. Introduction ..vi 1 Scope 2 Normativereferences. : Terms and definitions. 4 Application... 4.1 Design,specificapplications .8 4.2 Safety factors... 10 4.3 Input data..... 4.4 Facewidths. 4.5 Numerical equations ... 12 5 Influencefactors. 5.1 General.......... 12 5.2 Nominal tangential load,Ft,nominal torque,T, nominal power,P .12 5.3 Non-uniform load, non-uniform torque, non-uniform power. 5.4 13 5.5 Application factor,KA .13 5.6 .13 InternalDynamicFactor,K 5.7 Face load factor, KHβ 17 5.8 Face load factor, KFβ 23 5.9 Transverse load factors, KHa, KFa' .24 6 Calculation of surface durability (pitting) .26 6.1 Basic formulae.... .26 6.2 Single pair tooth contact factors, ZB, Zp .28 6.3 Zone factor, ZH .. 6.4 Elasticity factor, Ze ... 6.5 Contact ratio factor, Z, 6.6 Helix angle factor, Z .. 6.7 Allowable stress numbers (contact), OH lim ...31 6.8 Life factor, ZN.... 6.9 Influences on lubrication film formation, ZL, Z, and ZR ... ..32 6.10 Work hardening factor, Zw... 6.11 Size factor, Zx... 6.12 Minimum safety factor (pitting), SH min... ..34 7 Calculation of tooth bending strength ... 7.1 Basic formulae... ..34 7.2 Form factor, Ye, and stress correction factor, Ys ... ..36 7.3 Helix angle factor, Yp..... ..40 7.4 Toothroot reference strength, FE.... 7.5 Life Factor, YN... .41 Relative notch sensitivity factor, Ys rel .... 7.6 .41 7.7 Relative surface factor, YR rel .... .43 7.8 Size factor,Yx 44 ili ISO9085:2002(E) 7.9 Minimum safety factor (tooth breakage), SF n .44 AnnexA(normative)Specialfeatures ofless commongeardesigns Annex B (normative)Tooth stiffness parameters cand c Annex C (informative) Guide values for a