Experimental Study On The Friction And Wear Behavior Of A Friction Pair Consisting Of A Rigid Catenary Wire And A Pantograph Strip With Electric Current

With the acceleration of urbanization,urban rail transit has become the focus of urban public transport construction with its advantages of large volume,fast speed,punctuality and safety.The pantograph-catenary system is the only traction power supply device for electric locomotives.Pantograph strips and contact wires are two important parts of pantograph-catenary systems.At present,the wear of pantograph strips and contact wires in metro rigid pantograph-catenary systems is relatively severe,which not only increases the operation and maintenance costs,but also has a significant impact on the safe operation of metro trains.Therefore,it is of great academic significance and economic value to study the current-carrying friction and wear behavior of pantograph strips rubbing against contact wires with electric current.In this thesis,the current-carrying friction and wear behaviors of Cu-impregnated carbon strip/Cu-Ag alloy contact wire in the metro rigid pantograph-catenary system were studied under different working conditions(current,normal load and sliding speed)on a high-speed ring-block electric sliding test machine to simulate the operation conditions of the metro pantograph-catenary system,then the correlation analysis of several performance parameters was carried out.The results can be drawn as follows:(1)The friction coefficient decreases with the increase of the current and sliding speed,but increases with the increase of the normal load.When the normal load F_n>30 N,the friction coefficient tends to be stable.(2)The wear loss of Cu-impregnated carbon strips increases with the increase of the current and sliding speed.When the current I=200 A,with the increase of the normal load,the wear loss of Cu-impregnated carbon strips changes in a"U"shape.When the normal load F_n=25 N,the wear loss of Cu-impregnated carbon strips is the minimum.When the current I=400 A,the wear loss of Cu-impregnated carbon strips decreases with the increase of the normal load.(3)The current has the greatest influence on the surface morphology of Cu-impregnated carbon strips.When the current I<250 A,mechanical wear is a main wear mechanism of Cu-impregnated carbon strips.When the current I>300 A,oxidation wear,thermal wear and arc ablation are three primary wear mechanisms of Cu-impregnated carbon strips.(4)The current-carrying efficiency of friction pair decreases with the increase of the current and sliding speed,but increases with the increase of the normal load.When the normal load F_n>25 N,the current-carrying efficiency tends to be stable.(5)The arc energy increases with the increase of the current and sliding speed,but decreases with the increase of the normal load.When the normal load F_n>25 N,the arc energy tends to be stable.(6)The contact resistance decreases with the increase of the current and normal load,and increases with the increase of the sliding speed.(7)The temperature of Cu-impregnated carbon strips increases linearly with the increase of the electric current.When the normal load F_n=15～25 N,the temperature of Cu-impregnated carbon strips has no obvious regular change.When the normal load F_n>25 N,the temperature of Cu-impregnated carbon strips has a gradual downward trend.When the current I=200 A,the temperature of Cu-impregnated carbon strips increases with the increase of the sliding speed.When the current I=400 A,the temperature of Cu-impregnated carbon strips decreases rapidly with the increase of the sliding speed.(8)There are strong correlations between the current-carrying efficiency and wear loss of Cu-impregnated carbon strips,between the arc energy and wear loss of Cu-impregnated carbon strips,between the temperature of Cu-impregnated carbon strips and wear loss of Cu-impregnated carbon strips,between the current-carrying efficiency and arc energy,between the temperature of Cu-impregnated carbon strips and current-carrying efficiency,between the current-carrying efficiency and contact resistance,and between the arc energy and temperature of Cu-impregnated carbon strips.The correlation coefficients are all above 90%.