Analysis on Contact Strength of Needle Roller Bearing of Transmission and Effect of Surface Modification

Needle roller bearing is one of the most widely used parts in transmission; however, it often fails due to wear. In order to investigate the mechanism of fatigue damage, the three-dimensional model based on the sixth shift needle roller bearing of a six-speed manual transmission was established with Romax Designer. Then, the distribution of the contact stresses on bearing raceways was simulated under different loads. It is found that the stress concentration caused by the deflection of the needle rollers will increase the contact stress and lead to the indentations on the raceway surface. The composite surface modification of the roller raceway was employed, and the loading cycle test was carried out on the transmission test rig. The results show that the composite surface modification technique can improve the fatigue intensity of the contact surface and effectively prevent the indentation. Relevant experimental results provide technical guidance and theoretical basis for the optimization of needle roller bearings’ raceway strength.