根据钢轨砂带打磨作业原理,将钢轨与砂带的接触状态视为2个自由曲面接触;运用赫兹接触理论建立砂带与钢轨的接触模型,计算分析接触区域的形状、面积及其上的压力分布;将砂带上的磨粒简化为球顶圆锥模型,推导出磨粒切入深度与打磨压力间的数学关系,从单颗磨粒受力分析计算整个接触区域的切向力分布,进而建立钢轨砂带打磨功率的预测模型.在综合试验平台上进行36+号陶瓷磨料砂带打磨U71Mn钢轨圆环的试验,试验结果与预测模型的预测结果对比表明,打磨功率的预测值与试验值平均仅相差2.02％,证明了打磨功率预测模型的有效性和适用性.以60 kg·m-1钢轨砂带打磨为例,采用预测模型分析打磨功率与砂带速度配比对打磨宽度的影响.结果表明:打磨宽度虽由接触压力直接决定,但仍受打磨功率的约束,在同样打磨功率下,曲率半径为300 mm弧段可调整的打磨宽度范围最广,80 mm弧段次之,13 mm弧段最窄.%According to the working principle of abrasive belt rail grinding,the contact state between rail and abrasive belt was regarded as the contact between two free surfaces.The contact model was built based on Hertzian contact theory to calculate and analyze the shape,area and contact force distribution of contact zone.By simplifying single grit as hemisphere head cone model,the mathematical relationship between grain's cutting depth and grinding normal force was derived.The tangential force distribution of the whole contact zone was calculated based on the force analysis of single grit,and then the power prediction model for abrasive belt rail grinding was established.The experiment of grinding U71Mn by using 36+grit ceramic abrasive belt on the integrated test-bed shows that the average error between the predicted value and the experimental result is only 2.02％,which verifies the validity and applicability of the model.The matching analysis of grinding power versus belt speed for 60 kg · m-1 rail suggests that although the grinding width is decided directly by contact force,it is limited by grinding power,too.Under the same grinding power,the R300 segmental arc has the largest adjustable range for grinding width,R80 segmental arc the second and R13 segmental arc the narrowest.
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