Designing Advanced Motor Bearing of Electric Vehicles (EVs) Through Applying Circular Surface Texturing and Surface Engineering Methods of Cluster Magnetorheological Finishing (CMRF) and Laser Surface Hardening (LSH)

Motor bearing is a crucial part in electric vehicles (EVs) due to its critical function of supporting the output shaft to be able to transmit loads and rotate smoothly. As the electric motor in EVs operating in a harsh environment that experience high temperatures, pressures, and rotational speeds, considering design an appropriate motor bearing that can withstand these severe conditions is needed. Proper selections of bearing type, bearing material, lubricant and surface engineering methods if needed, would lead to a successful motor bearing that can operate effectively under the extreme operating conditions of electric motor. One efficient and common type of ball bearings is the deepgroove ball bearing, which has the advantages of a fast rotation in a minimal friction, a small contact area, and a high sealability to afford harsh conditions. Silicon nitride ceramics and AISI 52100 chrome steel were found to be the most appropriate materials that exhibit various properties that a motor bearing desires to have, such as high hardness, low friction and other properties related to tribology. An efficient lubricating grease, UCON OSP-32 base fluids polyalkylene glycol (PAG), was chosen due to its characteristics of high-temperature and chemical stability, low volatility, and good electrical insulation. To ensure the best performance of the motor bearing, the circular surface texturing technique and two surface engineering methods, cluster magnetorheological finishing (CMRF) and laser surface hardening (LSH), were applied to the bearing balls and races. Because of the careful selectins of bearing type, material types, lubricant and the surface modification methods, the design of the motor bearing has met several sustainability objectives, including increasing efficiency, mitigating environmental risks, decreasing weight, and reducing waste.