Nano Surface Modification of Hub Bearing Race Ways for Increasing the Dynamic Load Rating and Decreasing the Friction Loss

UNSM technology increases surface hardness, induces a large amount of compressive residual stress in the subsurface, refines the grain size into 50∼200 nm, and modifies the surface into micro dimple structure which reduces the friction coefficient about 50% simultaneously. In order to show the possibility of weight and friction reduction at Hub bearing application, hardness, roughness, residual stress, surface topology, friction coefficient and wear rate are compared before and after UNSM treatment of test specimens. Two type of rolling contact fatigue test and pin-on-disc test are carried out for test specimens. Finally dynamo test of hub bearing assembly is being carried out. Test results show that UNSM technology can reduce the weight and friction loss of hub bearing and is very effective technology for fuel consumption and CO2 emissions of vehicle.