车轮扁疤激起的轴箱轴承冲击特性

以CRH2型动车组为研究对象, 建立包含轴承的车辆-轨道动力学分析模型, 通过数值积分获得了轮轨冲击力时间历程、轮对和轴箱振动加速度时间历程、滚子与外圈滚道接触载荷时间历程; 结合已有的车轮扁疤分析模型, 研究了扁疤长度、车辆运行速度对轮轨冲击力的影响, 分析了扁疤冲击下轮对、轴箱的振动加速度响应特征以及外圈滚道接触载荷响应特征。研究结果表明: 轮对和轴箱受到的冲击加速度均随扁疤长度呈现增长的趋势, 轴箱受到的冲击加速度大于轮对受到的冲击加速度, 且轴箱受到的冲击加速度增长更快; 车轮扁疤会对外圈滚道接触载荷产生影响, 在滚道承载区域, 车轮进入扁疤区域时产生的冲击载荷作用效果为减小滚子外圈接触载荷, 在车轮离开扁疤区域时产生的冲击载荷作用效果为增大滚子外圈接触载荷, 在滚道非承载区域, 滚子与外圈同样会产生多次冲击; 车速为300 km·h-1, 扁疤长度小于30 mm时, 车轮进入扁疤区域滚子外圈受到的冲击载荷大于车轮离开扁疤区域滚子外圈受到的冲击载荷, 扁疤长度大于30 mm时, 车轮进入扁疤区域滚子外圈受到的冲击载荷小于车轮离开扁疤区域滚子外圈受到的冲击载荷; 在整个滚道区域内, 扁疤激扰激起的滚道冲击载荷呈左右对称分布, 且滚道区域越靠近对称轴, 受到的冲击载荷越大。 

Impact characteristics of axle box bearing due to wheel flat scars

Taking CRH2 EMU as the research object, the vehicle-track dynamics analysis model including bearing was established. The time histories of wheel-rail impact force, the vibration accelerations of wheelset and axle box, and the contact load between roller and outer ring raceway were obtained by the numerical integration. Combined with the existing wheel flat scar analysis model, the influences of flat scar length and vehicle running speed on wheel-rail impact force were researched. The vibration acceleration response characteristics of wheelset and axle box under flat scar impact, and the contact load response characteristics of outer ring raceway were studied. Research result shows that the impact accelerations of wheelset and axle box increase with the length of flat scar. The impact acceleration of axle box is larger than that of wheelset, and increases faster. The wheel flat scar can affect the contact load of outer ring raceway. In the bearing area of the raceway, when the wheel enters the flat scar area, the effect of the impact load is to reduce the contact load of the outer ring of the roller. When the wheel leaves the flat scar area, the effect of the impact load is to increase the contact load of the outer ring of the roller. In the non-bearing area of the raceway, the roller and the outer ring also have multiple impacts. At 300 km·h-1, when the length of the flat scar is less than 30 mm, the impact load on the outer ring of the roller entering the flat scar area is greater than that on the outer ring of the roller leaving the flat scar area. When the length of the flat scar is longer than 30 mm, the impact load on the outer ring of the roller entering the flat scar area is less than that on the outer ring of the roller leaving the flat scar area. In the whole raceway area, the impact load of the raceway caused by wheel flat scar is symmetrical distribution, and the closer the raceway area is to the symmetrical axis, the greater the impact load is.