基于磨耗稳定态的高性能摩擦磨损实验机研制

电气化铁路中电力机车靠受电弓滑板与接触网导线的滑动接触来获取动力,它们之间的摩擦接触状态直接影响到机车的运行速度和牵引力,同时其摩擦磨损性能决定了机车连续运行的时间和接触网导线的使用寿命.实际应用中二者构成了一对机械与电气耦合的特殊摩擦副,它们之间的磨耗过程是1个非常复杂的物理化学过程.通过研究发现,机车在正常运行过程中,滑板与接触网导线在运行一段时间以后会出现1个磨耗量较低、磨耗率相对稳定的阶段,在该阶段中摩擦副表面有一层光亮的膜层,称此时为磨耗稳定态,磨耗稳定态对磨擦副的性能及运行寿命具有重要的影响.为了对受电弓滑板与接触导线的载流磨耗特性进行实验研究,分析磨耗稳定态出现的规律,制作了1台高性能摩擦磨损实验机.实验机实验参数调节范围宽,测量精度高,功能强,也可用于电刷和电机滑环等滑动电接触实验.     

高速受电弓浸金属碳滑板载流摩擦磨损机制研究*

高速受电弓滑板面临高滑动速度、高电压、大电流等极限运行环境,运行环境的复杂性势必对滑板的使用寿命造成影响。为研究高速受电弓浸金属碳滑板载流摩擦磨损机制,通过对某高速列车受电弓浸金属碳滑板进行实车跟踪监测分析,得出高速受电弓滑板的真实工作条件,并通过扫面电子显微镜、电子探针、白光干涉仪对高速运行磨损后的浸金属滑板表面进行微观形貌分析、表面元素分布分析、表面粗糙度分析。结果显示：浸金属碳滑板的主要磨损机制为黏着磨损;浸金属碳滑板中间异常光亮的区域主要是由大量碳元素排列组成,且可能是由于滑板在进出站以及车辆段滑动时接触网未设置拉出,造成滑板中间磨耗较其他区域明显异常。磨耗后滑板表面成分分析可以得出,滑板表面氧元素原子占比较高,说明滑板表面发生了一定的氧化还原反应。     

受电弓状态未知问题的分析及改造建议

受电弓是地铁车辆从接触网上受流的装置,通过碳滑板与接触网导线的直接接触,从接触网导线上受取电源,为车辆提供牵引、空调、照明、控制等,因此,受电弓的状态直接影响列车的安全、可靠运行。通过对受电弓状态的实时监控,可及时、准确地发现受电弓出现问题的区域,了解弓网异常或受损情况。本文以南京S7号线高压电器箱内高速断路器HSCB断开后导致受电弓状态未知的问题为例,展开详细分析,并提出了改造建议。     

地铁车辆受电弓故障分析

以南京地铁2号线车辆为例,针对车辆受电弓常见的上框架出现裂纹和碳滑板出现异常磨耗的问题进行分析。得出导致上框架出现裂纹的原因主要是焊接质量问题和网线的异常冲击问题,碳滑板出现异常磨耗的原因是由于受电弓碳滑板与接触网之间受流工况的不同,导致碳滑板在使用中会出现断裂、剥离、掉块、裂纹、灼烧、偏摩等异常问题。提出了针对受电弓上框架出现裂纹和碳滑板异常磨耗问题的故障处理以及预防和整改措施。     

受电弓滑板载流温度静态特性研究

针对电气化铁路运营带来的受电弓-接触网问题,仅从传统的动力学角度研究分析已显不足,受电弓滑板载流温度分布关系的深入研究是对其的有力补充。从热学角度出发,通过将流入受电弓电流基于等效电功率形式施加到受电弓滑板上,建立滑板接触点附近的温度分布模型;运用FLUKE热像仪测量同等受流条件下滑板接触点温度分布规律,验证了仿真方法的有效性,为弓网系统电-热耦合关系进一步研究提供参考。     

双滑板受电弓磨耗的超声波检测方法

超声波检测滑板磨耗是以DSP TMS320LF2407A控制超声波传感器测量受电弓滑板的磨耗值,然后将获取的数据传输到检测主机.现在大部分电力机车都采用双滑板受电弓,因此超声波检测应能够检测前后两个滑板.在超声波检测单滑板受电弓的基础上,主要通过修改下位机的控制程序便可实现双滑板受电弓滑板的磨耗检测.     

降低弓网磨耗的受电弓主动控制策略研究

为了减少受电弓与接触网的磨耗,延长弓网使用寿命,同时保证弓网受流质量,在载流摩擦磨损理论、控制理论和微控制技术基础上,提出一种基于接触网磨损量检测和弓网接触压力受控的受电弓主动控制策略,并从软件方面对控制系统受到的电磁干扰进行防护设计。受电弓采用该主动控制策略,能明显降低弓网的磨损量,有效控制弓网接触压力的波动,提高和改善高速机车的受流质量。     

地铁受电弓碳滑板异常磨耗研究

为使碳滑板的磨耗及厚度处于正常范围，需要分析弓网接触压力、碳滑板材质、受电弓弓头结构和接触网拉出值对碳滑板异常磨耗的影响。受限于弓网系统自身的动态相互作用，弓网系统的设计与维护较为复杂。当碳滑板异常磨耗发生后，地铁运营公司需要投入人、财、物进行维保。由于济南轨道交通2号线运营周期较短，受电弓碳滑板异常磨耗事件暂未发生，为了给受电弓碳滑板异常磨耗的预防和维保提供技术支持，使其磨耗率控制在1.3×10^-4mm/km之内，基于国内各大城市地铁碳滑板异常磨耗事件统计数据，以重庆地铁6号线弓网拉弧事件作为案例借鉴，围绕碳滑板异常磨耗的影响因素展开理论研究。     

弓网系统滑动电接触表面磨损特征研究

为探究弓网系统受电弓滑板在不同电流、接触压力和滑动速度条件下的磨耗特性,开展弓网载流磨损实验,探讨不同工况下摩擦副的载流效率、电弧能量、摩擦因数和温度;分别使用金相显微镜与表面粗糙度仪对实验后的滑板磨损区域进行分块多次测量,使用一种基于Otsu大津算法的图像处理方法,将凹坑部分从形貌图像中提取并进行标记计算,统计分析不同工况下凹坑面积、数量和粗糙度参数（包括轮廓算术平均偏差和最大轮廓谷深）的变化情况。结果表明：随着电流的增大,凹坑面积和数量增加,粗糙度参数减小;随着接触压力的增大,凹坑面积减小,凹坑数量先减小后略有增大,粗糙度参数减小;随着滑动速度的增大,凹坑面积、数量和粗糙度参数都增大。     

地铁刚性弓网系统接触线磨损特性试验研究

为研究地铁刚性接触网系统接触线磨损的规律,以地铁刚性接触网系统常用的浸金属碳滑板/铜银合金接触线作为摩擦副,通过模拟地铁弓网系统运行参数,使用载流摩擦磨损试验机研究有、无电火花放电情况下,浸金属碳滑板与铜银合金接触线直流电滑动过程中磨损量、摩擦因数、载流效率随滑动距离的变化。试验结果表明：电火花放电会使得接触线与浸金属碳滑板磨损量显著上升,出现电火花放电时摩擦因数较小,弓网系统载流效率会明显降低同时出现大幅波动。试验后对碳滑板和接触线表面形貌的观察可知：电火花放电会使得浸金属碳滑板表面烧蚀坑数量和尺寸大小增加,同时会出现滑板材料大面积剥落和表面裂纹增多的问题,接触线表面形貌变得更加粗糙。     

A procedure for the wear prediction of collector strip and contact wire in pantograph–catenary system

The effects of friction and electrical phenomena like arcing and sparking govern the wear rate in the sliding contact between the contact wire and the collector strip, these two effects are mutually interconnected in a complex manner. A means of investigating the wear of the collector strip and the contact wire is to carry out laboratory tests that allow to perform comparative tests between different material combinations and to establish the dependence on the main parameters such as sliding speed, contact force and current intensity. A problem to be considered in the application of the laboratory test results is their extrapolation to the real operating conditions, in order to assess the effective benefit among different solutions. In this paper, a procedure that combines a wear model for the contact between collector strip and contact wire with the simulation of the dynamic interaction between pantograph and catenary is proposed. The adopted wear model is based on the wear map concept, including the effect of electrical current flow, and it is tuned by means of the results obtained on laboratory test rig.The dependence of the electrical contact resistance on the contact force between each contact strip of the pantograph and the contact wire of the overhead line is considered and the corresponding electrical current on each of the two collectors of the pantograph is evaluated. Instantaneous values of contact forces and electrical current are then fed into the wear model and the amount of the wear of the collector strips and of the contact wire along the overhead line is calculated, generating an irregular profile of the contact wire.The proposed procedure is applied to two cases: in the first one the wear of the contact wire using copper collector strips and graphite collector strips for dc line are compared. In the second one, the consequence of the variation of the mechanical tension of the contact wire on the wear levels is predicted.     

弓网电弧模拟发生装置及其试验

随着高速铁路的快速发展,弓网电弧现象及危害愈发明显,值得深入研究。对国内外现有弓网电弧模拟发生装置进行了综述分析,设计了一套弓网电弧模拟发生装置。该装置通过旋转轮盘与碳刷相对运动,产生旋转电弧,能够模拟受电弓与接触网的相对运动。试验初步测试了电弧对系统的电压电流的影响。     

基于模糊反演法的参数不确定弓网接触载荷控制

弓网系统具有复杂的电气、机械耦合特性,提高弓网受流性能是目前高速铁路系统亟待解决的关键问题,而弓网主动控制则是稳定弓网接触载荷、改善其受流质量的重要措施。从控制理论的角度出发,针对弓网系统存在风载荷与参数不确定性的问题,提出了基于模糊系统的弓网接触载荷反演精确控制方法。具体而言,采用虚拟控制律,逐步反演递推选择Lyapunov函数,设计模糊系统逼近不确定性与虚拟控制律微分,并进行相应的稳定性分析。仿真与实验结果表明,所提出的模糊反演控制策略能减弱弓网不确定性的影响,且能有效抑制弓网接触载荷的波动,并改善其受流质量。     

电力机车受电弓动态性能优化

在建立单臂受电弓模型的基础上,对高速铁路受电弓在运行过程中的接触力性能、几何参数及弓头轨迹等进行优化,结果表明在新的参数下弓网系统的接触力波动得到明显抑制,受电弓动态性能得以提高,为进一步开发高速机车受电弓提供了借鉴。     

Performance evaluation and design optimization using differential evolutionary algorithm of the pantograph for the high-speed train

The global trend in the railway industry is the effort to increase the maximum speed and stability of a train. For an electric railway vehicle to meet this driving performance, stable electric power should be supplied by a catenary system. Various factors affect the current collection performance, most important of which is the dynamic characteristics of a pantograph. In this paper, the sensitivity analysis and design optimization of a pantograph for a high-speed train were conducted using a finite element method. The dynamic catenarypantograph interaction was analyzed by using the commercial finite element analysis software, SAMCEF. The pantograph was modeled as a three degrees of freedom mass-spring-damper system, and the pre-sag of the contact and messenger wire due to gravity was implemented. The span data of a high-speed line was applied in the analysis model. And the dynamic characteristics of the pantograph model were obtained by a performance test. The reliability of the simulation model was verified by comparing the analysis contact force results with the test data. By simulation, the mean contact force and its standard deviation etc. were evaluated, and then sensitivity of the pantograph was analyzed. Based on the sensitivity analysis results, the specification of the pantograph was optimized. In the optimization process, response surface analysis and differential evolutionary algorithm were applied to define the regressive function and to determine the optimum values for stable current collection performance. Finally, the improvement of the current collection performance was verified by comparing the optimum specification results with the original specification.     

组装式滑板对地铁接触线犁削磨损的影响

在弓网载流摩擦磨损实验台上,用直流恒流电源对组装式浸金属碳滑板以及银铜合金接触线进行摩擦磨损试验,研究组装式碳滑板的接缝间隙和滑板间高度差对地铁接触线犁削磨损及滑板异常磨耗现象的影响.试验结果表明:组装式碳滑板高度差会严重刮伤接触线,是接触线犁削磨损的主要原因,而接缝间隙仅会轻微划伤接触线;80 N以上的法向力会显著减...     

Effect of arc discharge on the wear rate and wear mode transition of a copper-impregnated metallized carbon contact strip sliding against a copper disk

Wear of the contact strip on the pantograph of electric railway vehicles is governed mainly by arc discharge occurring simultaneously with break of contact between the strip and trolley wire. As a step to clarify the wear mechanism of metallized carbon contact strips under the occurrence of contact break arc discharge, a detailed sliding wear test of 30 min duration was carried out for the combination of a copper-impregnated carbon strip and a copper disk at a sliding speed of 100 km/h. The worn surfaces of the strip and disk were observed every 5 min. The voltage drop and electric current were measured throughout the test, and the occurrence and energy of the arc discharge were evaluated for each revolution of the disk. The wear process is considered in terms of the wear mode transition, and the effect of arc discharge on the mode transition and wear rate of the strip is discussed.     

表面粗糙度对滑动电接触磨损率的影响

在电气化铁路弓网系统中,磨损率是衡量列车运行状态与接触导线使用状态的重要指标。为了充分模拟弓网系统中磨损率情况,利用自行搭建的滑动电接触摩擦磨损试验机对滑板和接触导线进行摩擦磨损试验,分析滑板表面粗糙度、法向压力、接触电流与运行速度对磨损率的影响。得出结论:滑板磨损率随滑板初始表面粗糙度、接触电流、法向压力、运行速度的增加而增加,而高载荷下粗糙度对于磨损率的影响降低;滑板摩擦从磨合期进入稳定摩擦期存在一个临界表面粗糙度,当滑板初始表面粗糙度值等于临界粗糙度值时,其磨损率最低;不同初始表面粗糙度的滑板在跑合期内磨损过程不同,在稳定摩擦期内磨损过程趋于一致,且摩擦试验后滑板表面粗糙度也接近。