Test Methodology for Evaluating the Performance of Lubricants for Gears in E-Mobility Applications – Reliable Assessment of the (Seize) Load-Carrying Capacity of E-Mobility Lubricants

The research project was conducted in cooperation with FVA Forschungsvereinigung Antriebstechnik e. V. (FVA No. 988 I).

Current developments in drive technology show a clear trend toward high electric motor speeds. This allows the electric motor to be designed more compactly and operated more efficiently. In the context of e-mobility, this translates to an increased range. To further increase the efficiency of the powertrain, novel lubricants are being developed that, among other things, enable high transmission and gear efficiency. Typically, these lubricants feature particularly low viscosities. To minimize transmission losses, low coefficients of friction are desirable; friction linings are generally not found in most e-mobility applications.
Standard test procedures allow for a comparative evaluation of lubricants with regard to scoring, pitting, and gray spots. In the test, a damage severity level (SKS) or the runtime until failure is determined based on characteristic limit parameters, which can then be used to classify lubricants into load-carrying capacity classes or categories. The motivation behind this research project is to develop a reliable method for evaluating the load-carrying capacity behavior of such novel
Lubricants under relevant operating conditions typical of e-mobility. In this basic research project, the following work packages were carried out:

• Commissioning and Validation of a Novel FZG High-Speed Gear Tension Test Stand
• Systematic studies on wear resistance under realistic test conditions typical of e-mobility, as well as spot checks on long-term behavior at elevated rotational speeds
• Proposal for a Practical Testing Methodology to Assess the Corrosion Resistance of E-Fluids

The results of the project will serve as a basis for a potential follow-up IGF project. The objective of the research project was achieved.