Reliability Analysis For The Equal Vavle Used In Shanghai Metro Line 1 DA01 Vehicles

When designing the brake system of metro trains, countries in the world choose pneumatic brake as a safe brake method. The principle of Shanghai Metro Line 1 DA01 vehicles air brake system operation is that the compressed air comes from air supply unit in the train and it will create a control signal according to its control mode, amplified in the equal valve, input to the block brake unit and applying the brake by the block brake unit. Three ways of the brake need to be amplified by equal valve and equal valve becomes to be the only way. In the whole brake system bake control unit and block brake unit are abundant in structure, but the equal valve is the only part in every vehicles. Thus, the equal valve is the critical part which can affect reliability of the whole brake system. We must research the reliability of the equal valve.Firstly,the configuration of the equal valve is analyzed. Then the functional modules are plotted out. And the functional block diagram of the system, as well as the reliability block diagram is drawn. Secondly, the reliability model of the equal valve is set up. Thirdly, fault analysis is carried out based on the functional modules. By using FMEA method, each module is numbered and subdivided. Single point failures and their probabilities of occurrence are listed. The criticality grade of the failures and the criticality matrix are given as well. By using FTA method, the grouping failure modes and the minimum cut sets which can cause system failure are analyzed. Reliability indexes of the equal valve are decided through quantitative estimates. Fourthly, it is explored on how to obtain failure rates of the equal valve components. While for mechanical parts, scene reliability data needs to be accumulated by rail transport operation companies. It can also be obtained by doing laboratory reliability test. And for that, a reliability test bed is needed. Finally, the reliability test bed is studied for the critical components of micro-computer controlled straight electro-pneumatic braking system air channel.Then the paper discusses the reliability test for the equal valve and proofs the reliability of the equal valve using laboratory reliability test. At last, gets the life curve distribution pattern of the equal valve, then extends the results to various types of train brake system valves.In the foundation of the reliability analysis, the paper researches maintainability and supportability of the equal valve. Estimating the service life of the equal valve by the times when the valve is used. To achieve reasonable configuration in maintenance according to ordered maintain schedule.