【作者】 姜国强；

【导师】 郭凤仪；

【作者基本信息】 辽宁工程技术大学 ， 机械设计及理论， 2010， 博士

【摘要】 高速电气化铁路的弓/网系统是电力机车的动力来源,载流摩擦磨损是受电弓滑板与接触网导线间滑动电接触状态的主要特征,二者之间构成了一对在复杂环境条件下的机械与电气磨损耦合的特殊摩擦副。随着电力机车速度的不断提高,受电弓滑板与接触网导线之间的载流摩擦磨损行为变得越来越复杂,高速下的受流将出现更多问题,制约机车的进一步提速。因此,以国家自然科学基金项目(高速滑动电接触下的磨耗稳定态研究50677027)为依托对电力机车受电弓滑板与接触导线的摩擦磨损特性和载流稳定性进行了实验研究。首先研制了一台滑动电接触摩擦磨损实验机(专利号:CN200920012471.9),该实验机可以真实模拟电力机车的实际运行状况,实现导线和滑板的均匀磨耗,可以对受电弓滑板与接触导线的摩擦因数、接触点温度、相对滑动线速度、滑板往复移动次数、接触导线与滑板磨耗量以及摩擦副间接触电流、接触电压、接触电阻等参数的实时在线测量和数据储存,可在一定范围内实现电流、载荷、速度等的单、多因素控制。设计了基于LabVIEW的监控界面和数据处理系统,可对下位机检测的数据进行实时显示与记录,并生成各种相应的波形曲线和报表,为进一步的理论分析创造了条件。通过对浸铜碳滑板、铜基粉末冶金滑板与铜锡导线的对磨实验,研究了大电流、重载荷、高滑动速度下的摩擦磨损行为,通过实验得出滑板的载流摩擦磨损特性、受流稳定性、接触点温升特性等,并利用SSX-550扫描电子显微镜,对滑板的磨损形貌进行了分析。结果表明:在接触压力和载流相同的情况下铜基粉末冶金滑板的接触电阻小于浸铜碳滑板的接触电阻;接触压力相同、载流不同时,浸铜碳滑板的接触电阻变化率更小、受流稳定性较好;相同载流下,两种材料的滑板温升速率不同;随着电流的增大,浸铜碳滑板的温升幅度比铜基粉末冶金滑板的大,但后者的温升幅度逐渐减小;电流较小时,滑板温升的主要因素为摩擦热与焦耳热,当电流增大到一定值,焦耳热与电弧热是滑板温升的主要原因。接触压力、滑动速度、加载电流这三个对受电弓滑板载流摩擦磨损性能有重要影响的因素中,电流因素的影响程度最大。不同载流情况下,两种滑板的磨耗率随着电流的增大而增大,但铜基粉末冶金滑板随着电流的增加磨耗率变化较大,浸铜碳滑板材料磨耗率变化较小、耐磨性能较为理想。在相对滑动速度恒定的条件下,增大摩擦副间的接触压力,在使其摩擦因数增大的同时,却改善了滑板的受流质量和摩擦副的接触稳定性,从而使磨耗率呈现先减小后增大的“U”形变化规律,磨耗率最小时对应的接触压力阈值随接触电流的增大而增大。在接触压力恒定条件下,摩擦副间的摩擦因数随滑动速度的增加而不断减小,但其接触稳定性及受流质量却不断恶化,磨耗率随滑动速度的增加而减小,随接触电流的增加而增大。论文提出磨耗稳定态的概念,即受电弓滑板与接触导线在一定条件下对磨一段时间以后出现的一个磨耗量较低、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,磨耗稳定态对磨擦副的性能及运行寿命具有重要的影响。在到达磨耗稳定态之前为过渡状态,这一阶段的摩擦磨损形式以宏观电弧烧蚀和磨粒磨损为主。通过调节接触压力,提高相对滑动速度可以缩短过渡状态的时间,使其快速进入磨耗稳定态,此时摩擦磨损的主要形式是微观电弧侵蚀与粘着磨损。更多还原

【Abstract】 The pantograph catenary system is power source of electric locomotive of high-speed electrified railway. Current-carrying friction and wear are the main features of the sliding electrical contact state between pantograph and catenary wires. They constitute a special frictional pair coupled electro-mechanical wear under complex environmental conditions. Current-carrying friction and wear behavior between pantograph and catenary wire has become increasingly complex with the continuous increasing speed of electric locomotive. And more problems on current collection will occur under high-speed, which restricts the further acceleration of electric locomotive. Therefore, the friction and wear characteristics and the stability of current-carrying of the electric locomotive pantograph and contact wire were studied by relying on the National Natural Science Foundation of China (Research on wear steady-state under high-speed sliding electrical contact, NO. 50677027).A sliding electrical contact friction and wear tester was developed firstly (Patent No. CN200920012471.9). It can simulate actual operating conditions of electric locomotive, achieve uniform wear of pantograph and wire, and the friction coefficient, the contact point temperature, relative sliding speed, sliding back and forth movement frequency, the wear loss between contact wire and pantograph, contact current, contact voltage, contact resistance and other parameters are online measured in real time, and the data are saved, which can be achieved within a certain current, load, speed and other single-factor and multi-factor control. Monitoring interface and data processing system were designed based on LabView software. The data detected by the lower computer can be displayed and recorded real-timely, and waveform curve and the reports variously were generated, which create the conditions for further theoretical analysis.Through conducting lots of experiments on copper based powder metallurgy pantograph, immersed copper carbon pantograph and copper-tin contact wire and studying friction and wear behavior under high current, heavy loads, high sliding speed, the current-carrying friction and wear characteristics, current-carrying stability and contact point temperature rise characteristics of the pantograph were obtained. The wear morphologies of pantograph were analyzed by using SSX-550 scanning electron microscope. The results showed that the contact resistance of copper based powder metallurgy pantograph is less than that of immersed copper carbon pantograph in the same condition of contact pressure and current-carrying, contact resistance change rate of immersed copper carbon pantograph is smaller than that of copper based powder metallurgy pantograph and stability of current-carrying is better in the condition of same contact pressure and different current-carrying, the temperature rise rate of two materials pantograph is different in the same current-carrying, the temperature rise range of immersed copper carbon pantograph larger than that of copper based powder metallurgy pantograph with the increasing current, but the temperature rise range of later decrease gradually, the main factors of temperature rise are frictional heat and Joule heat when the current is smaller, the main factors of temperature rise are Joule heat and arc heat when the current increases to a certain value.Among the three important factors, which respectively is contact pressure, sliding speed and load current, current have the greatest influence to current-carrier friction abrasion characteristic of pantograph slide. Under different carriers,the wear rate of two kinds of slide increase with increasing current. But the wear rate of copper based powder metallurgy pantograph slide changes greatly with increasing current, whereas leaching of copper carbon slide has a small change amplitude of wear rate and a fairly perfect wear-resisting property.Under a constant relative sliding speed, both current-carrying quality of slide and contact stability of friction pair are improved while friction factor increases due to increasing contact pressure of the friction pair. Therefore, wear rate presents "U"-shaped variation which firstly decreases and then increases. Contact pressure threshold increases with increasing contact current corresponding to minimal wear rate. Under a constant contact pressure, the friction factor between the friction pair decreases continuously with increasing sliding speed, contact stability and carrier quality deteriorate continuously, while wear rate decreases with increasing sliding speed and increases with increasing contact current.This paper proposes the concept of steady state, which is a state of lower wear loss and relatively stable wear rate after a period of rubbing with each other between pantograph slide and contact wire under certain condition. In steady state stage, there is a bright film layer on the surface of friction pair. Wear steady state has a great influence to the performance and service life of friction pair. The state before reaching the wear steady-state is called transition state, during which the friction and wear form is mainly macroscopic arc erosion and abrasive wear. The period of transition state will be shortened and reach wear steady state rapidly by increasing relative sliding speed and adjusting contact pressure. In the wear steady state rapidly, the friction and wear form is mainly microscopic arc erosion and adhesive wear.更多还原