Research On The Reliability Of The Installation Interface Of The Tread Brake Unit

With the growth of national economy and technology in our country, the urban rail have developed continuously. As the special operation of the line, the train needs to start and brake frequently. The train also needs a larger train braking deceleration because of its short distance between the platforms. Tread brake is the main mode of urban rail brake, therefore, the tread brake unit is required to have high stability and safety. The joint bolts which connect the tread brake unit and bogie frame may lose efficacy when braking. The safety and reliability of the connection interface between the tread brake unit and bogie frame is an important factor for the safety of the train. In light of this situation, it is necessary to analyze and research the reliability of the installation interface of tread brake unit.This paper introduces the development of installation interface technology and the reliability design of mechanical structure at home and abroad. Combined with the problems that need to be solved in this paper, a suitable method is chosen to study the installation interface of the tread brake unit.The tread brake unit and the bogie frame are connected by bolts. The tread brake unit is subjected to multiple loads when braking, and the load is transmitted to the connecting bolts. Therefore, it is necessary to consider the influence of various load factors on the analysis of the installation interface. As the shear stress is the main factor that causes the yield strength of the material, in this paper, the tangential force of the bolt is mainly studied. Through the calculation model of eccentric shear bolt combined with the rotation center theory, the connection interface is analyzed.The 3D model is established based on the finite element simulation method, and the different forces are setted according to TB/T 3058-2002. Then the actual stress condition of the installation interface is studied. The static strength analysis and transient analysis are carried out, then the stress of the connecting bolts are compared under different conditions. The results show that the interface of the tread brake unit is safe and reliable.Using the stress-strength interference model, the relationship between stress and strength in different condition is calculated by the method of Monte Carlo. Then the reliability of installation interface is analysed. Through the calculation of reliability, you can determine whether the installation interface is safe and reliable.The stress of installation interface is analysed by theoretical analysis and finite element simulation, then the optimal number and placement of bolts and the optimal position of the hardstop are determined. Human-computer interaction interface is designed by MATLAB GUI interface. This interface consists of three modules:the main parameters of the joint bolts, the tread brake unit without hardstop and the tread brake unit with hardstop. It can pre-calculate the force condition of the connection interface in different situations and realize the parametric design. Users only need to input related parameters in the corresponding interface, they can determine the reliability of the connection interface.