Theoretical Analysis And Software Development Of Weighing And Spring Adjustment For EMU Vehicle

The EMU’s wheel weight bias will affect the play of traction and braking force. So in order to ensure the EMU’s operating performance, weighing the EMU to detect wheel weight deviation is required in the process of repairing and manufacturing. According to CRH2A, B, E EMU level three maintenance specification, the EMU’s wheel weight bias should not exceed 8 per cent in the Weigh-in-Motion or 4 percent in the static weighing.If the EMU’s wheel weight bias exceeds the specified value, spring adjustment is needed to decrease it. In recent years, domestic and overseas scholars have made a great deal of researches on adjusting railway vehicles’wheel weight and brought forward many different weighting adjustment algorithms. But the domestic research is relatively rare and the weighing process in the field relies on experience. By analyzing the rule of wheel load distribution, this paper makes a research on the effects of spring adjustment technology on EMU’s wheel load, and according to the iterative algorithm proposed in this paper, software to guide EMU’s weighing adjusting is developed.This paper built a spring-mass model of EMU weighing and studied the rule of the wheel load and axle load under the influence of process errors and center of gravity deviating, deriving the wheel load affected stiffness matrix of adding adjusting shims and adjusting the height of the air spring. The analysis results showed that the change of the center of gravity position in the weighing process can be ignored and the existing spring adjusting technology cannot adjust the axle load. Combined with EMU’s spring adjusting technology, this paper summarized the parameters to guide EMU’s weighing adjustment, which can express whether the EMU can be adjusted and whether it is required to add adjusting shims. Thus using these parameters can guide EMU’s weighing adjustment. Combined with the guidance parameters and stiffness matrices, this paper wrote iterative algorithm to calculate the required number of shims.This paper set up EMU static weighing simplified models by using Multi-body dynamics simulation software SIMPACK and verified the validity of the stiffness matrices by simulating the variation of wheel load after adding adjusting shims, the validity of the adjusting algorithms is also verified by analyzing field weighing data. On this basis, this paper developed the EMU weighing adjustment software by using programming software VB, which can calculate the required number of shims in the axle-box spring in the process of EMU weighing. Thus comprehensive spring adjustment can be achieved and the efficiency of EMU weighing can be increased.