MSE and IWM research new methods for greasing heavily loaded bearing raceways


Project ”Polytetrafluorethylene (PTFE) - Greasing in Heavily Loaded Bearing Raceways“ has Been Launched and was Introduced at the German Tribology Conference 2018

High, respectively low, temperatures, low velocity, aggressive ambient media or a vacuum may prevent machine elements to be lubricated with oils or greaes; this requires solid lubricants to be applied instead. The use of polytetrafluoroethylene (PTFE) as a solid lubricant is widespread in machine elements with low contact pressures, such as plain bearings. The PTFE is applied to the surface as a coating and is therefore directly available for lubrication. Due to its low solidity, the PTFE prevents the provision of such lubricants in highly loaded rolling contacts (p>1000 MPa).
The research project “Polytetrafluorethylene (PTFE) – Greasing in heavily loaded bearing raceways” aims at developing a new approach of PTFE-greasing for heavily loaded bearing raceways at the Institute for Machine Elements and Systems Engineering. Research will be jointly carried out with the Fraunhofer Institute for Mechanics of Materials IWM and is sponsored as part of the DFG research program 2074 “Fluid-free greasing systems with high mechanic loads”.

First, this research project analyses the effects of PTFE on a microscopic level before their mechanisms are used to develop an optimized greasing process for bearing raceways on macroscopic levels. Therefore, atomistic simulation methods are initially applied on a microscopic level to model the relevant chemical, mechanical and thermal processes within the greasing process’ individual interacting effects.
The results, for instance in form of mechanical PTFE-key values or friction figures, are validated by accompanying nano analytical testing.

Findings are transferred to the macroscale through continuum mechanical simulations and experimentally within an in situ tribometer which facilitates a specific analysis of the above mentioned interacting effects inside a Large-Chamber REM. Afterwards, the PTFE transmission rates (macroscopically measured inside the in situ tribometer) are matched against the transmission rates, which have been calculated through the microscopic models.
This way, validated assessments of lubrication conditions based on chemical and mechanical description models under different boundary conditions should be made possible. Eventually, this aims at lining bearing raceways with PTFE.

Besides introducing the launch of SPR 2074 at this year’s German Tribology Conference, it is planned to present the project’s future milestones as well.