ISO/TR TECHNICAL REPORT 18792 First edition 2008-12-15 Lubrication of industrial gear drives Lubrification des entrainements par engrenages industriels Reference number ISO/TR 18792:2008(E) @ISO2008 T by IHS under lic ted without license from IHS Not for Resale ISO/TR 18792:2008(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The IsO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by IsO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT @ ISO2008 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, IsO's 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 22 749 09 47 E-mail [email protected] Web www.iso.org Published in Switzerland @ IS0 2008 - All rights reserved Tby IHS unde I without license from IHS Not for Resale ISO/TR 18792:2008(E) Contents Page Foreword Introduction 1 Scope 2 Terms and definitions. 3 Basics of gear lubrication and failure modes. 3.1 Tribo-technical parameters of gears.. 3.2 Gear lubricants....... 3.3 Basefluidcomponents 3.4 Thickeners... 3.5 Chemical properties of additives . 3.6 Solid lubricants ...... 10 3.7 Friction and temperature 10 3.8 Lubricating regime... 3.9 Lubricant influence on gear failure. 4 Test methods for lubricants 15 4.1 15 4.2 Otherfunctionaltests .16 5 Lubricant viscosity selection ... .19 5.1 Guideline for lubricant selection for parallel and bevel gears (not hypoid). 19 5.2 Guideline for lubricant selection for worm gears.... .24 5.3 Guideline for lubricant selection for open girth gears. 6 Lubrication principles for gear units 26 6.1 Enclosed gear units.... 27 6.2 Open gearing ... 34 < Gearboxserviceinformation.. 39 7.1 Initial lubricant fill and initial lubricant change period .39 7.2 Subsequent lubricant change interval..... 7.3 Recommendations for best practice for lubricant changes 40 7.4 Used gear lubricant sample analysis... 41 Bibliography 52 Fiqures Figure 1 - Load and speed distribution along the path of contact.. Figure 2 - Scraping edge at the ingoing mesh . 5 Figure 3 - Schematic diagram of shear effects on thickeners Figure 4 - Mechanisms of surface protection for oils with additives... 11 Figure 5 Examples of gear oil wear test results.. 15 Figure 6 Immersion of gear wheels .. 27 Figure7Immersiondepthfordifferentinclinationsofthegearbox 29 Figure 8 Immersion of gear wheels in a multistage gearbox .. 30 Figure 9 Examples of circuit design, combination of filtration and cooling systems ... .34 Figure10 Immersionlubrication 37 ili Copyright International Organizationandardizalionghtsreserved put license from IHS Not for Resale ISO/TR 18792:2008(E) Figure 11—Transfer lubricatior .37 Figure 12 — Circulation lubrication Figure 13 Automatic spraying lubrication 38 Tables Table 1 Symbols, indices and units.. Table 1 (continued).... Table 2 General characteristics of base fluids . Table 3 Example of influence factors on wear . Table 4 Example of influence factors on scuffing load (transmittable torque).. Table 5 Example of influence factors on micropitting (transmittable torque) . Table 6 - Example of influence factors on pitting (transmittable t