Design of a System to Measure Film Thickness and Lubrication Condition in Large Bearings

The time that bearings can operate before maintenance is needed strongly depends on the life of the lubricating grease in the bearings. The grease should form a reliable film to separate the metallic surfaces. However, the operation mechanically and thermally ages the lubricant inside the bearing. If the lubricant fails this means the bearing will also fail. The calculation of the life time of the lubricant is based on models and is often assumed in a conservative manner. This means maintenance (change of lubricant or even exchange of bearing) is conducted before it is technically necessary. This means that often the lubricant could still function for a time, however is replaced before reaching its full life time.

In this project a system will be designed which enables the measurement of the lubrication state inside grease lubricated bearings. The system will make use of electrical methods and can thus be applied to real bearings. With the help of this system it will be possible to improve and fine tune the life time models. Furthermore, they may enable users to actually base their maintenance on the real condition inside the bearing. This will allow the maintenance to be done at an optimal time and thus save material and make the systems more reliable. It also supplies a tool to study the lubrication of large bearings in more detail which can lead to development and optimisation of future systems.