The Failure Theory And Experimental Analysis On Key Parts Of Composite Brake Chamber Of Truck

The composite brake chamber, essential part of brake system, installed on the drive axle, is working to transform the pressure of compressed air to mechanical force that making brake camshaft rotate. The main reason why the failure of composite brake chamber inevitability is that the working environment and loading conditions are very complex. The failure study of composite brake chamber can predict and avoid the case of brake failure happening timely. However, the existing failure testing instruments of composite brake chamber are hardly to detect fault factors as well as fault diagnosis and lookup, which is limited by the testing model and conditions and so on. In conclusion, the research on the failure of composite brake chamber has become the key of the brake system at present.The main task of this paper is to study the essential part of composite brake chamber on truck. According to the structure characteristics, the performance indicators and failure causes, the composite brake chamber is divided into three modules: the parking brake module, the crane brake module and the connector module. Combined with actual working conditions and failure cases of composite brake chamber, studies the failure factors of three modules respectively, and then determine the failure factors.Two mathematical failure models were established respectively based on parking brake module and crane brake module in order to explore the failure of the critical state of composite brake chamber according to the principle of composite brake chamber in the real vehicle environment and the mechanics working characteristics and material properties of essential parts. The dynamic parameters such as the push rod stroke and working load were measured by performance tester of composite brake chamber. And then we can predict the failure source and its extent of damage for composite brake chamber by the two mathematical failure models. At the same time, all the stress distribution diagram and fatigue damage diagram can be calculated of the two modules with the help of the finite element simulation.As to the connector module, theoretical analysis and modeling method were applied respectively in accordance with the sealing property of the composite brake chamber. In order to obtain the influence of seal performance of O ring, the compression ratio of materials and the design of groove type were discussed. The influence of groove clearance and friction coefficient is the main factor lead to the failure. The simulation results that under different groove clearance and friction coefficient can be calculated based on ANSYS workbench by importing material parameters and the dynamic parameters in real vehicle conditions.In this paper, the research for truck provides an important guiding significance to the composite brake chamber’s design and development, the failure model and simulation results have good theory value and practical significance to timely discover and prevent the occurrence of brake failure.