Composite fault mechanism and vibration characteristics of high-speed train axle-box bearings

Axle-box bearings are crucial components of high-speed trains and operate in challenging conditions. As service mileage increases, these bearings are susceptible to various failures, posing a safety risk to high-speed train operations. Thus, it is crucial to examine the deployment methods of axle-box bearings. A dynamic model of axle-box bearings for high-speed trains with compound faults is constructed by setting up separate faults in two rows of double-row tapered roller bearings based on a single-fault model. The model's high accuracy in expressing compound faults is verified through corresponding experimental results. Then, the frequency domain diagram of system vibration response under varying rotational speed conditions is obtained, and the amplitude corresponding to the single frequency is extracted and analyzed to identify the optimal rotational speed band for composite fault diagnosis. Finally, the optimal speed band is analyzed under different faults, different load sizes, and different composite fault types. It can be concluded that the determination of the optimal speed band is solely influenced by the composite fault type and is independent of the fault and load sizes. Finally, it is concluded that the energy proportion of faults in different positions changes periodically with the change in speed, and this phenomenon is not affected by the fault sizes or load magnitude.