The central objective of the project was to improve the Slow speed weartest for gear oils (DGMK 377-01) for transfer to a standard-compliant test method with a comprehensive calculation of the wear life of gears.
Research report published: Evaluation of gear oils for wear-prone mobile and stationary drives
BMWK-funded project completed
The BMWK has funded a research project on this subject, which has been completed after 2.5 years.
First, relevant influencing variables on the test method were identified and their effects on the test result quantified. Furthermore, the repeatability and reproducibility of the test method as well as the differentiability of the results were determined in a comparison test among seven laboratories and compared with the current state of the art. On this enlarged test basis, it was possible to derive extended definitions and specifications for the test procedure, which ensure a comparable performance of the test.
Furthermore, the transfer of the results of a standardized gear oil wear test to the procedure for calculating wear in the design of gears of different types was investigated. In the known test procedures, pairings of case-hardened gears are used. In many cases, however, case-hardened and quenched and tempered (and thus significantly softer) gear pairs are also installed in practice.
The risk of wear and the intensity of wear differ considerably between these types of gearing. Targeted investigations with this material pairing under systematic variation of relevant influencing variables have made it possible to derive regularities that allow wear calculations to be extended for these applications.
This provides a test method whose suitability for evaluating the wear resistance of gears has been proven and which can differentiate the load-bearing capacity of different lubricants. Based on the results, the wear calculation according to Plewe can be used to make statements on the service life under operating conditions and, via the newly introduced conversion, also on the service life of gear stages with different surface hardness.
Research Center for Gears and Gear Systems
Technical University Munich
Cooperation and expert network
The research work was initiated by the DGMK Lubricants Expert Committee and carried out in cooperation with the FVA Forschungsvereinigung Antriebstechnik e.V. (Research Association for Drive Technology). A group of experts from the lubricant and additive industry, from the drive, machine and transmission construction sectors and from suppliers accompanied the project.
DGMK Research Report 799 has been published and can be ordered directly from DGMK free of charge.
The IGF project (20679 N) of the research association DGMK Deutsche Wissenschaftliche Gesellschaft für nachhaltige Energieträger, Mobilität und Kohlenstoffkreisläufe e.V.. Große Elbstraße 131, 22767 Hamburg, Germany, was funded by the German Federal Ministry of Economics and Climate Protection through the German Federation of Industrial Research Associations (AiF) as part of the program for the promotion of joint industrial research (IGF) on the basis of a resolution of the German Bundestag.