地铁车轮磨耗及其对轮轨匹配状态的影响

对国内某地铁线路的车轮磨耗规律进行了现场调查和分析。车轮磨耗集中于轮缘根部和踏面-25~30 mm范围。LM32模板动车车轮踏面磨耗突出区为-8~-4 mm,25万~40万km里程车轮最大磨耗量为2.5~4.0 mm。采用薄轮缘LM30模板镟轮的拖车车轮踏面磨耗集中在-10~10mm范围,19万km以内里程踏面磨耗量为0.2~0.5 mm。利用轮轨接触几何理论和轮轨滚动接触理论,研究不同车轮磨耗状态下的轮轨静态匹配性能,包括接触点对分布和轮轨接触应力,分析车轮表面裂纹的机理。车轮轮缘根部与钢轨轨距角集中接触容易导致接触光带偏向轨距角。轮缘根部及踏面上小曲率半径区与钢轨集中接触是产生车轮踏面接触疲劳的主要原因。

Metro Wheel Profile Wear and the Effect on Wheel/Rail Compatibility

Field survey and analysis on the wear characteristics are carried out on one metro line in China.The main wear is located on the flange root and wheel tread area from-25 mm to 30 mm in the lateral direction of wheel profile.For motor wheel with LM32 profile module,the dominant wear occurs in a range of-8 ～-4 mm,the maximum wear depth is from 2.5 mm to 4 mm for wheels with the operation mileages from 250 0000 to 400 000 km.While for trailer wheel with thin flange LM30 profile module,the main wear concentrates to-10 ～ 10 mm on tread,the wear depth is 0.2 ～ 0.5 mm for wheel with the operation mileage under 190 000 km.Based on the theories of geometrical contact and rolling contact,the wheel/rail profile compatibility is studied,including the static contact point distribution and contact stress under different worn profiles.The root cause of tread crack is also discussed.The concentrated contact between flange root and rail gauge corner tends to shift the contact band to rail gauge corner.The rolling contact fatigue on wheel surface is mainly due to the concentrated contact between wheel and rail with small curvatures,such as the flange root and the field side of tread area.