Bogie frame is an important part of rail vehicle, and fatigue cracks impose highly adverse impacts on the running safety. Through field test, extensive investigation and simulation, the cause of early failure of bogie frame is analyzed. The research shows that the bogie hunting instability will affect the stress distribution of the bogie frame, and even lead to the cracking of bogie frame. Because the equivalent conicity of wheelset and clearance of primary suspension will affect the critical speed of the train, the bogie hunting instability occurs when the critical speed is lower than the vehicle running speed. The wheel should be reprofiled regularly and the locating rubber sleeve should be replaced to avoid the hunting instability of the train.

转向架车架是轨道车辆的重要组成部分，疲劳裂纹对运行安全产生很大的不利影响。通过现场试验、广泛调查和仿真，分析了转向架框架早期失效的原因。研究表明，转向架摆动失稳会影响转向架构架的应力分布，甚至导致转向架构架开裂。由于轮对的等效锥度和主悬架间隙会影响列车的临界速度，当临界速度低于车辆运行速度时，就会出现转向架摆动失稳。定期对车轮进行修型，更换定位胶套，避免列车摆动不稳。