Fault Simulation And Experimental Study For Axle Box Bearing Of High Speed EMUs

With the continuous improvement of China's high-speed rail line of eight verticals and eight horizontals,the technology of high-speed railway developed rapidly in China,and high-speed train demand increased dramatically,therefore,the safe operation of the train is particularly important.As one of the most critical parts of the vehicle,the situation of the axle box bearings directly affects the safety of the train traffic.At the same time,High-speed train develop toward to high-speed and heavy,the conditions of axle box bearing is complex,and experimental conditions are limited.It is costly and difficult if we only use the experimental methods to obtain fault data.Therefore,it is of great significance to fault monitoring of the axle box bearing that playing dynamic simulation for the failure axle box bearing of high-speed train,simulate the fault signal of the bearing,analyze the characteristics of stress and motion characteristics of fault bearing.In this paper,the fault simulation is using the FAG807811.02 bearing,which is mainly used in CRH3 EMU axle box.Firstly,the static analysis method was used to analyze the static equilibrium moments of different spalling failure bearings,and then the dynamic operation method was used to simulate the normal bearing and the exfoliation bearing models.The stress,velocity and speed of the components under different spalling bearings were analyzed.The vibration characteristic analysis of the fault simulation signal was carried out.And the stress results of the two simulation methods are compared.Finally,the vibration test was used to verify simulation results that the influence of load on the bearing vibration.Simulation results show that at a speed of 300 km/h,fault characteristic frequency is 230 Hz when the outer ring is spall.Mixed spalling failure can lead to more intense bearing vibration.The maximum load components in bearing is roller,and the average stress of the inner ring is higher than that of the outer ring.Increasing of radial force will increase the load bearing area.Spall on different parts will increase the stress of roller.The effect of spall on inner ring on stress of other components is most significant.When the axle box bearing is running and the surface of the roller is contacting the inner and outer ring raceway,the stress of contacting region is rather concentrated.Roller surface and raceways are prone to fatigue damage.The outer ring peeling and roller peeling have a greater impact on its own stress.The inner ring peeling will reduce the speed of the roller and itself,and the exfoliation of the inner ring stress concentration is more serious.The outer ring and roller appear spalling at the same time,which rise the maximum stress high to times of the normal state.