Design Considerations for Wheel Bearing Outer Ring for Electric Vehicles

Electric vehicles demand better drag performance from wheel bearings in order to achieve longer range. Electric vehicles are heavier than their corresponding ICE vehicles. They also have higher torque output. Due to this there would be higher loads at bearing to knuckle joint. The higher loads may require higher clamp loads to keep the joint secure. The higher clamp load may increase wheel bearing outer ring distortion or out of roundness. The outer ring distortion would increase the drag permanently and reduce the bearing life. So, it is critical to minimize outer ring distortion even after the assembly with higher clamp load and throughout the life. In this paper it is planned to cover the design considerations for wheel bearing outer ring and knuckle interface to keep distortion minimum. A DOE will be used to understand the effects of M12 vs. M14 mounting bolts, knuckle stiffness, OR mounting area, knuckle bolt PCD, bearing outer ring flange thickness. A 2nd DOE will investigate the non-linear effects for the strongest factors from the initial study. It will also study the effect of outer ring concavity.