Investigations into the failure mechanisms of grease-lubricated rolling bearings - significance of the aging of different thickener systems.

In order to determine the suitability of a grease for a rolling bearing application and to estimate its operating life, various time-consuming and cost-intensive laboratory tests are carried out during the development phase. In this cooperative project, the influence of mechanical, thermal, oxidative and catalytic stress on the grease and its lubricating effect was to be investigated. A clever experimental design was to be used to describe the influence of the individual factors independently of one another, as well as their interactions. The aim was to obtain, for the first time, reliable findings on how the thickener structure of a lubricating grease changes during aging and mechanical loading, how this can be detected and what influence this has on the lubrication and thus on the performance and service life of the rolling bearing. This project objective has been achieved, even though many questions remain unanswered and only a small part of the grease formulations available on the market could be investigated. What is important, however, is that a test strategy has now been described with which the lubricant developers can carry out further individual investigations in a targeted manner.

The IGF project (21251 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.