Effect of housing design on oil splash lubrication in an E-drive Unit through Computational Fluid Dynamics Simulation

Proper lubrication of gears and supporting bearings is crucial for the optimal functioning of an e-drive unit, particularly under high-speed and high-load conditions. Understanding the causes of bearing failure requires an analysis of the oil splash pattern in a testbed with a transparent casing. Additionally, modifying the gearbox and housing designs can be both time-consuming and costly to achieve performance goals. As an alternative, Computational Fluid Dynamics (CFD) modeling provides a virtual testing environment that allows for quicker design evaluations and reduces product development time. This study focuses on using CFD to assess a housing design aimed at enhancing lubrication for the rear and front drive units (RDU/FDU) in electric vehicles. Multiphase flow simulations were conducted using the volume of fluid (VOF) method in the commercial CFD software Simerics-MP+. This software generates an unstructured Cartesian mesh and manages complex mesh movements through a volume remesh technique. The findings indicate that the oil collection feature improved lubrication by redirecting oil splash towards the bearings. It was also noted that the rotational direction of the gearbox impacts the splash oil collection for bearing lubrication, which resulted in better bearing lubrication in RDU than for the FDU at low speeds, whereas FDU showed relatively better lubrication at higher speeds. This computational study highlights the effectiveness of CFD in analyzing oil splash lubrication and enhancing the design of e-drive units.