Rolling bearings are operated with more than 90 % of grease lubrication, and faulty lubrication is responsible for more than 80 % of bearing failures. For operation in mixed and boundary friction, an additive-based wear protection is necessary. Surface active AW/EP additives have the potential to form wear protective boundary layers on bearing surfaces. However, a wear-resistant design using AW/EP additives is not yet possible. Therefore, the aim of this project was to analyse the influence of grease composition and temperature on wear protection in rolling bearings. For this purpose, various lubricating greases were characterized and extensive component tests were carried out on the FE8 test rig. Subsequently, the additive-based boundary layers were investigated microanalytically. The wear protection effect is strongly temperature-dependent, with increased wear masses occurring in the range from 40 °C to 60 °C. The choice of lubricant has a decisive influence on the wear protection effect in the rolling bearing.
Research Report Published: Wear Protection in Rolling Bearings
A polyurea thickener promotes a suitable additive-based boundary layer structure in comparison to a lithium thickener. The AW/EP additives investigated show different behaviour, although they usually do not significantly increase wear protection.
MSE Institute for Machine Elements and Systems Engineering, RWTH Aachen
GFE Gemeinschaftslabor für Elektronenmikroskopie, RWTH Aachen
The DGMK Research Report 774 has been published in German under the title "Wirkungsgrenzen des Verschleißschutzes verschiedener Schmierfettformulierungen in Wälzlagern". It can be ordered directly from the DGMK.
The IGF project (19279 N) of the research association DGMK Deutsche Wissenschaftliche Gesellschaft für Erdöl, Erdgas und Kohle e.V., Überseering 40, 22297 Hamburg was funded via the AiF within the framework of the programme for the funding of Industrial Collective Research (IGF) by the Federal Ministry for Economic Affairs and Energy on the basis of a resolution of the German Bundestag.