机车牵引状态下曲线通过导向特性研究

考虑车轮与钢轨的运动特性及轮周牵引力,推导出机车在牵引状态下通过曲线时的轮轨蠕滑率计算公式,并对曲线通过时的轮轨横向动态相互作用特性进行仿真计算与分析;同时研究牵引力大小对转向架导向性能的影响,对比分析了机车牵引与惰行状态下的导向性能。理论仿真分析结果表明:牵引力可以改变轮轨纵向蠕滑力的大小和方向,与惰行工况相比,牵引状态下的轮对导向力矩有所减小,轮对的自导向能力减弱,不利于曲线通过;提高牵引力,总轮轨蠕滑率将很快达到饱和状态,牵引力越大,轮轨纵向蠕滑力越大,两侧纵向蠕滑力差值越小,机车轮对自导向能力越差,轮对冲角增大,而轮轨横向蠕滑力越小;当牵引力增加到一定程度时,总轮轨蠕滑率超过极限状态,曲线通过时两侧轮径差太小而出现打滑和空转的现象。

Study on the Steering Characteristics of Curve Negotiation under Locomotive Traction

Taking the motion characteristics of wheel/rail and the traction force at wheel rim into consideration,the formula is deduced in this paper to calculate the creepage between wheel and rail at curve negotiation under locomotive traction.Simulation calculation and analysis are carried out on the characteristics of wheel/rail lateral dynamic interaction at curve negotiation.At the same time,the effect of traction forces on the steering performances of bogie is investigated.The steering performances under locomotive traction and idle running are compared and analyzed.Theoretical simulation and analysis results show that the traction force can influence the size and the direction of wheel/rail longitudinal creep force.Compared with the condition of idle running,the steering moment of wheelset under traction is reduced and the self-steering capacity of wheelset is weakened,which is unfavorable for curve negotiation.With the increase of the traction force,the total creepage arrives at the saturated state rapidly.And the bigger the traction force is,the larger the longitudinal creep force is,the smaller the difference value of the outer and inner longitudinal creep force is,the worse the self-steering capacity of locomotive wheelset is,the bigger the attack angle is,and the smaller the lateral creep force is.When the traction force is added to certain level,the total creep force exceeds the limiting value and the difference between the wheel diameters of the two sides is too small.This will result in the phenomena of the slip between wheel and rail.