Rolling bearings are essential components in modern technology, from turbines and electric motors to industrial machinery. Their reliability is often constrained by the lifetime of the lubricating grease, which is generally shorter than the fatigue life of the bearing and thus becomes the limiting factor. This project investigates how to extend grease life and thereby improve bearing durability and reliability.

This project aims to optimise the specifications and potentially formulation of base oils in lubricating greases for rolling bearings. The performance of the bearing is primarily determined by grease life. Extending grease life increases bearing durability and reduces the frequency for maintenance. Currently, purely physics-based grease life models are lacking due to the incomplete understanding of lubrication mechanisms. However, one well-known factor is bleed - the separation of oil from grease- which plays a crucial role in maintaining lubrication.

There are two strategies to extend grease life: (1) regulation of the bleed rate, and/or (2) usage of a base oil that works very efficiently with only minute quantities. In this context, this project addresses two central questions: what makes an oil efficient and how does the oil properties influence the bleed behaviour. The answer to these questions will enable on the one hand bearing manufacturers to select greases that are optimised for specific applications, thus guaranteeing extended grease lifetime. On the other hand, grease manufacturers will be able to optimise their grease formulations for enhanced operational performance in terms of protective capabilities, while reducing maintenance frequency.