Thermal Simulation of High-Speed EV Transmission Bearings for Minimum Lubricant Volume 2022-01-1120
Minimizing the lubricant volume in a transmission system reduces the churning losses and overall unit costs. However, lubricant volume reduction is also detrimental to the thermal stability of the system. Transmission overheating can result in significant issues in the region of loaded contacts, risking severe surface/sub-surface damage in bearings and gears, as well as reduction in the lubricant quality through advanced oxidation and shear degradation.
The increasing trend of electrified transmission input speeds raises the importance of understanding the thermal limits of the system at the envelope of the performance to ensure quality and reliability can be maintained, as well as being a key factor in the development, effecting internal housing features for the promotion of lubrication.
A nodal bearing thermal model will be shown which utilizes thermal resistances and smooth particle based CFD for determining bearing lubricant feed rates during operation. Heat transfer is evaluated transiently for a range of operating conditions with the bearing contact mechanics solutions applied for determination of the contact thermal resistances and the corresponding lubricant flow across the bearing. The nodal bearing model will be shown to have been validated against measured thermal data from a high-performance vehicle e-axle with a significant focus on the determination of the minimum lubricant volume.
Citation: Toth, M., Gangl, D., Bansal, H., and Leighton, M., "Thermal Simulation of High-Speed EV Transmission Bearings for Minimum Lubricant Volume," SAE Technical Paper 2022-01-1120, 2022, https://doi.org/10.4271/2022-01-1120. Download Citation
Author(s):
Marton Toth, Dávid Gangl, Hemant Bansal, Michael Leighton
