Electric vehicles (EVs) require improved drag performance from wheel bearings to achieve a longer range. EVs are heavier and have higher torque output compared to internal combustion-powered vehicles. Due to the increased weight and torque of EVs, there will be higher loads at the bearing-to-knuckle joint. These increased loads may necessitate higher clamp loads to maintain joint integrity. However, higher clamp loads can lead to distortion or reduced roundness of the wheel bearing outer ring. Such distortion permanently increases drag and reduces bearing life. Therefore, after vehicle corner assembly with higher clamp loads, it is critical to minimize outer ring distortion during the initial assembly and throughout the bearing's lifespan.
This paper will cover the design considerations for the wheel bearing outer ring to minimize distortion, utilizing Computer-Aided Engineering (CAE) analysis for various designs. A Design of Experiments (DOE) will be conducted to understand the effects of M12 versus M14 mounting bolts, assembly stiffness, outer ring mounting area, knuckle bolt pitch circle diameter (PCD), concavity, and bearing outer ring flange thickness. A second DOE will investigate the non-linear effects of the strongest factors identified in the initial study.