Dynamic Characteristic Analysis of Bogie Gearbox Bearings Under Typical Wheel-Rail Excitation

The bogie gearbox bearing is one of the critical components in the running gear of trains, and its dynamic characteristics significantly influence the safety and stability of the entire system. In addition to internal excitations within the gearbox, during actual operation, the system is notably affected by wheel-rail disturbances, such as wheel tread wear and track irregularities. As train operating speeds increase, these impacts become more complex and pronounced. This study focuses on the cylindrical roller bearings at the input end of the bogie gearbox. A dynamic model accounting for the effects of centrifugal force and lubrication was proposed by analyzing the force characteristics of the rolling elements, inner and outer rings, and the cage, respectively. The model was verified through the velocity characteristics of the internal components. Furthermore, a method for obtaining wheel-rail excitation based on a coupled dynamic model of the bogie and wheel-rail system was proposed. Based on this, a comparative analysis was conducted on the internal contact load characteristics and the vibration characteristics of each component of the bogie gearbox bearings under different wheel polygonal excitation amplitudes and orders, as well as under the combined influence of track irregularities and wheel polygons. The results indicate that wheel polygonal excitation and track irregularity excitation have significant effects on bearing vibration and contact load. An increase in the polygonal order and amplitude intensifies the contact load between the rolling elements and the outer ring, thereby increasing bearing vibration. Additionally, a higher polygonal order leads to more frequent impacts between the rolling elements and the outer ring. The coupling effect of wheel-rail excitations further amplifies bearing vibration and contact load.