钢轨打磨车磨削过程建模研究

发布时间：2018-07-17 15:29

【摘要】：钢轨因车辆的频繁行驶而产生的磨耗与损伤严重影响了行车的平稳性与安全性,需要采用钢轨打磨车进行在线打磨修复。由于打磨经验及工艺机理的缺乏,作业过程中难以保证打磨的效率及质量,甚至发生过度磨削、损伤钢轨的严重事故。轨道交通的快速发展使得这一问题越来越突出。为此,本文结合钢轨打磨车的作业特点,建立钢轨打磨车磨削性能与工艺参数之间的理论模型,探讨钢轨打磨的工艺规律,为钢轨打磨作业及打磨装备的研发提供理论支撑。明确钢轨打磨参数对钢轨廓型变化的影响规律是设定打磨关键参数、实现目标廓型的重要依据。因此,首先基于作业形式建立打磨砂轮与钢轨的空间几何模型,分别探讨不同砂轮摆角与磨削深度对钢轨廓型、磨削面积及打磨面宽度的影响规律。其次,进一步分析由多个打磨砂轮构成的打磨模式对钢轨廓型变化的影响。最终,利用上述规律实现所需打磨模式的设定：依据砂轮数目、钢轨目标廓型及待磨廓型以确定砂轮的磨削位置、摆角及对应的磨削深度。上述分析得到不同打磨参数对钢轨的影响规律并确定打磨模式的设定准则,而为了接近砂轮真实的磨削状态,须构造具备稳定磨削层的砂轮模型以实现对打磨过程的描述。具体的,以磨削层球体磨粒截圆面积和的方差作为磨削层均匀度的判断准则,将等间距分布的球体磨粒空间模型进行多次振动达到磨削层空间稳定状态；选取具有代表性的磨削层作为打磨砂轮的磨削表面,并将其表面磨粒的形状与位姿进行随机变换以构建能够提供稳定切削角的表面磨粒,最终生成打磨砂轮磨削表面形貌。基于磨粒空间分布所获得的砂轮表面形貌生成是进行磨削性能分析、获得被磨钢轨数据的重要基础。首先,结合打磨砂轮特点及打磨车行车条件可获得磨粒与钢轨的接触线长度及切削轨迹分布等磨削要素随切削速度的变化规律。其次,基于.磨粒切削钢轨的几何与受力模型建立磨粒对钢轨表面的三维切削模型并获得被磨钢轨的形貌变化,得到打磨砂轮设定功率与磨粒名义切削深度、砂轮磨削深度的对应关系。最后,利用钢轨打磨试验台验证上述规律的有效性,包括单个砂轮设定功率与磨削深度的关系验证以及多个砂轮顺序打磨钢轨的效果验证。钢轨打磨车的打磨作业是在行驶状态下完成的。其所具备的轨道车辆特性将影响打磨砂轮与钢轨的磨削接触关系,改变打磨砂轮的磨削位置或磨削深度,进而影响磨削结果。为此,首先建立钢轨打磨车的垂向动态模型,分析钢轨打磨车行驶状态对打磨砂轮垂向位移的影响。其次,建立钢轨打磨车三维模型以分析其行驶状态所引起的轮对横移现象,并获得不同的轮对横移量在横向及垂向上对打磨砂轮磨削位置的影响。最终,获得钢轨打磨车行驶状态对砂轮磨削的影响规律并对相应的磨削模型进行修正,以更加贴近实际的钢轨打磨作业状态。
[Abstract]:The wear and damage of rail caused by the frequent driving of the vehicle seriously affect the stability and safety of the train. It is necessary to use the rail grinding car for on-line grinding and repair. Due to the lack of grinding experience and the process mechanism, it is difficult to ensure the efficiency and quality of the grinding in the process of operation, even over grinding, and the serious damage to the rail is damaged. Therefore, the rapid development of rail traffic makes this problem more and more outstanding. Therefore, this paper, combining the working characteristics of the rail grinding car, establishes the theoretical model between the grinding performance and the technological parameters of the rail grinding car, discusses the technological rules of the rail grinding, and provides the theoretical support for the rail grinding operation and the research and development of the grinding equipment. The influence of grinding parameters on the change of rail profile is an important basis for setting the key parameters of grinding and realizing the profile of the target. Therefore, the geometric model of the grinding wheel and rail is established based on the operation form, and the influence of the angle and depth of the grinding wheel on the rail profile, the grinding area and the width of the grinding surface is discussed respectively. Further analysis is made on the influence of the grinding mode composed of multiple grinding wheels on the change of rail profile. Finally, the required grinding mode is set by the above rules: the grinding position of the grinding wheel, the swing angle and the corresponding grinding depth are determined on the basis of the number of grinding wheels, the target profile of the rail and the shape of the grinding profile. The rule of the influence of the parameters on the rail and the setting criterion of the grinding mode is determined. In order to close the grinding state of the grinding wheel, a model of grinding wheel with stable grinding layer must be constructed to describe the grinding process. The distributed spherical abrasive space model is used for multiple vibration to achieve the stability of the grinding layer, and the representative grinding layer is selected as the grinding surface of the grinding wheel, and the shape and position of the surface abrasive particles are randomly transformed to build the surface grinding grain which can provide the stable cutting angle and finally produce the grinding surface of the grinding wheel. The surface morphology of the grinding wheel based on the spatial distribution of abrasive particles is an important basis for grinding the grinding rail data. First, the length of the contact line of the abrasive and rail and the distribution of the cutting trajectory with the cutting speed can be obtained by the characteristics of grinding wheel and the driving condition of the grinding vehicle. Secondly, based on the geometry and stress model of the abrasive cutting rail, the three-dimensional cutting model of the abrasive grain on the rail surface is established and the change of the shape of the worn rail is obtained. The corresponding relationship between the nominal cutting depth of the grinding wheel and the grinding depth of the grinding wheel and the grinding depth of the grinding wheel is obtained. Finally, the effectiveness of the above rules is verified by the rail grinding test bench. It includes the verification of the relationship between the set power of a single grinding wheel and the grinding depth and the verification of the effect of multiple grinding wheels in the order of grinding the rail. The grinding operation of the rail grinding car is completed under the running state. The characteristics of the rail vehicle will affect the grinding contact between grinding wheel and rail, and change the grinding position or grinding of the grinding wheel. For this reason, the vertical dynamic model of the rail grinding vehicle is first established, and the influence of the running state of the rail grinding wheel on the vertical displacement of the grinding wheel is analyzed. Secondly, the three dimensional model of the rail grinding car is established to analyze the shift of the wheel set caused by the running state, and the transversal displacement of different wheelset is obtained. And the effect of vertical grinding wheel on grinding wheel grinding wheel. Finally, the influence law of the running state of the rail grinding wheel on grinding wheel grinding is obtained and the corresponding grinding model is corrected so as to be closer to the actual working state of the rail grinding.
【学位授予单位】：北京交通大学
【学位级别】：博士
【学位授予年份】：2015
【分类号】：U216.65;TG580.6

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