Research On Dragging Problem Of Rail Vehicle Hydraulic Driving Walking System

Abstract:Closed hydraulic driving system is widely used in walking vehicle because of its good driving stability, compact structure, and little reversing impact. Aiming at the existing dragging problem of rail vehicle hydraulic driving system when working, and starting from the analysis of dragging reasons and conditions, research of the dragging performance of the system was done in this paper with an example of full-face cleaning machine. The main contents are as follows:1. The hydraulic driving vehicle application status, development trend, system working principle and research situation of dragging performance were summarized. The current solution of the dragging problem of hydraulic driving vehicle and its disadvantages were analyzed. The objective, significance and contents of this paper were identified.2. Starting from the analysis of the power matching, traction and the system kinematics of the closed walking system, research of the hydraulic circuit and the reason of dragging of the closed walking system were done, which included the reason of sudden pressure change and the stall of the engine because of dragging. Thus, the relationship between the dragging behavior of the system and the engine speed was obtained.3. According to the obtained dragging behavior, the conditions of engine stall of the closed walking system because of dragging were gained. Therefore, two methods of preventing the engine from stall because of dragging were proposed, namely, initiatively raising the engine rotate speed to increase its friction moment and adding an auxiliary hydraulic pump. Finally, the mathematical mode of the system was built and the system dynamic performance was analyzed.4. The simulation mode of the closed walking system was established. The simulation results showed that, on a ramp of a certain gradient and under the working condition of sharp slowdown, raising the engine’s friction torque or adding an auxiliary pump could all effectively avoid the engine stall.5. The experiment platform of the closed walking speed was built on a full-face cleaning machine to do experiment research on the working condition of dragging and the raised two methods. The results showed that the two strategies could all effectively solve the problem of engine stall because of dragging, which proved the strategies correct.