With the country's large investment in the development of railway construction, China's railways have been continuously expanded and extended, and the speed of operation has been accelerating. Intercity trains have become the first choice for ordinary people in all medium and short-distance cities. At the same time, in order to solve the congestion of ground transportation, major cities have vigorously developed urban light rail, subway, BRT rapid transit, etc., which greatly facilitates travellers and makes practical contributions to reducing urban carbon dioxide emissions.
Many large cities have brought many problems to the use and maintenance of urban light rail and subway. At the same time, there are still many problems in the structure of rail transit locomotives such as urban light rails and subways, and locomotives running on railway trunk lines. In particular, the running device is obviously different. The so-called running device is the part of the vehicle that supports the vehicle body and takes on the task of the vehicle. At the beginning of the railway development, the vehicles were relatively short. The vehicle's running gear was relatively simple. It only included two wheel pairs that were mounted on the lower part of the car body by springs. This type of vehicle is called a two-axle car.
With the development of vehicles, the number of axles per vehicle has increased, and the performance requirements for vehicles have been continuously improved. Therefore, the wheelsets, axle boxes, suspension devices, basic brake devices and structures of the vehicles are formed into a single unit. For bogies, the running gear of modern vehicles refers to the bogie of the vehicle. The bogies of urban light rail and subway are less than the locomotives in weight, and the complexity of processing and manufacturing is also simpler than that of locomotives. However, there is a commonality in the application, that is, the wheel and the rail will produce rolling friction when the car is running. The smaller the curvature of the vehicle curve, the faster the passing speed, the greater the centrifugal force, causing the wheel rim to contact the inner side of the rail. By increasing the formation of the rails, even if a hydraulic anti-snake device is used between the carriage and the running gear, the vehicle will increase the probability of swaying and the long-term rolling friction between the tread surface of the wheel and the upper plane of the rail during operation. The result is an increase in the contact surface and an increase in the friction factor. Figure 1 shows the condition after the wheel is worn.
figure 1
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