根据双拉杆式轮对轴箱定位系统的结构特点,分析产生轮对轴箱定位偏心的原因,并且由于轮对轴箱定位偏心而使轮对在滚动过程中产生纵向振动,轮对的纵向振动又会引起轮轨纵向蠕滑率的变化,进而引起轮轨纵向蠕滑力的变化,从而影响到机车对轮轨蠕滑力的调整和轮轨黏着的利用.从轮轨接触点位移量动态变化的微观角度分析轮对纵向振动与纵向蠕滑率/力振动之间的关系,并仿真研究轮对纵向振动对机车动力学性能及轮轨接触特性的影响.结果表明:当轮对发生较大纵向振动时,对机车的垂向平稳性影响较大,而对机车的横向平稳性影响很小;当轮对轴箱定位偏心量达到5mm时,机车的垂向平稳性超标;当一系纵向定位刚度为1.6 MN·m-1时,轮对受到的激励频率与其纵向振动固有频率相近,引起轮对的纵向共振,进而使得机车纵向失稳;在轮对纵向振动的作用下,随着轮轨纵向蠕滑率的增大会引起轮轨纵向蠕滑力的增大,当轮轨纵向蠕滑力超过轮轨摩擦极限时,车轮将发生宏观滑动进而引起车轮空转.
The causes for the positioning eccentricity of wheelset axle box were studied according to the structure characteristics of double-rod wheelset axle box positioning systen.Positioning eccentricity will make wheelset vibrate longitudinally in its rolling process. Wheelset longitudinal vibration will cause the change of wheel/rail longitudinal ereepage, and then it will cause the change of wheel/rail longitudinal creep force. Thus, it will eventually affect the adjustment of wheel/rail creep force and the use of wheel/ rail adhesion. The relationship between wheelset longitudinal vibration and longitudinal creepage/creep force was analyzed from the microscopic aspects of the dynamic changes of the displacement of wheel/rail contact point. The influence of wheelset longitudinal vibration on locomotive dynamic performance and wheel/rail contact characteristics was simulated. The results show that when larger wheelset longitudinal vibration occurs, it has greater influence on locomotive vertical stability, but smaller influence on locomotive lateral stability. When wheelset positioning eccentricity reaches 5 ram, the vertical stability exceeds the standard limit. When the stiffness of primary longitudinal positioning is 1.6 MN ~ m-1 , the excitation frequency acted on wheelset is similar to its natural frequency of vertical vibration. Wheelset longitudinal resonance will happen and cause locomotive longitudinal instability. It will cause the increase of wheel/rail longitudinal creep force with the increase of wheel/rail longitudinal creepage under the influence of wheelset longitudinal vibration. When longitudinal creep force exceeds wheel/rail friction limit, wheelset macroscopic sliding will happen and it will result in wheelset idling.