Motion Reliability Research On The Space Mechanism In The Door Of Railway Vehicle

With the rapid development of economy, the demand for coal is increasing year by year in our country. Efficient and simple railway coal vehicle should be developed to improve the efficiency of coal transport and realize the mechanization and automation in loading and unloading, and the bottom door is the key part. In recent years, it happens to open automatically in bottom door of some coal hopper cars, so, it is meaningful to analyse the motion reliability.In this article, the simple planar linkage mechanism is firstly started to research the influence factors of motion reliability, considering the main reasons of the error are original manufacturing error, motion pair clearance error and motion pair wearing error. And the mathematical modeling of motion reliability is carried on, which is feasible through examples. On the basis of’effective length model’theory, the continuously contacting’effective length model’is put forward. According to the Archard wearing theory, a new motion pair wearing model is built through movement and force analysis. It is proved that the mathematical model can also be used in space mechanism.A bottom door in coal hopper car is double-PSSR-type space linkage, according to the mathematical model of motion reliability, the reliability analysis is carried on for the whole opening action. By analyzing the movement and the force, contrast the motion reliability in three different conditions:original manufacturing error, original manufacturing error and motion pair clearance error, original manufacturing error, motion pair clearance error and motion pair wearing error. By the analysis of the result, it is concluded that the motion pair wearing error impacts most.This mathematical model can not only solve the motion reliability of bottom door at any time, but also can obtain wearing status in each motion pair, which is easy for maintaining. If the reliability range is given, it can also estimate the working life by this method.In this method, it is more closed to reality by considering motion and force condition, and suitable for reliability calculation under various operating conditions. The whole calculation process is completed by the mathematical software Matlab, which saves much time and manpower. The changing process of motion reliability can be shown in graph form, and it is simple and easy to analyse. The established mathematical model has general applicability, and it can not only be applied in plane and space mechanism, but also be extended to multi-bar linkage.