The Research On Dynamic Characteristics Of The Unloading Valve

The objects of the research on dynamic characteristics are the stability and the dynamic response performance. The research object in this paper is dynamic characteristics of the unloading valve in the pneumatic control system. The purpose of the research is to eliminate the instability in the opening transient, increase the qualified rates of the first assembly, reduce production cost, and increase assembly efficiency. At present, there are few of examples about it. Moreover, transfer function method is used to establish mathematical model, which is complex and disagree with the complex system. So the simple and effective method has important significance.First, the model parameters are determined, such as helium thermophysical properties, physical properties of the materials and the parameters of the elements. Then the dynamic mathematical model is established by means of power bond graph, and the restrictions are imposed on the model. In the end, the digital simulation is completed based on the Matlab/Simulink. The opening transient model and the closing transient model are established.An assembly rule is established based on theoretical analysis and the simulation. And the rule is used to increase the stability in the opening transient. The effects of each parameter in the opening transient model are analyze, such as the precompression and circumferential opening of the piston ring, the initial tension force and flexibility of the spring, the quality of the main valve core, the air lock of the pilot valve, the gas volume of the main valve chamber and the outlet chamber. The measures to develop the dynamic characteristics of the opening transient are put forward. And the effects of assembly dimension of the piston ring to the dynamic characteristics of the closing transient are analyze based on the simulation.Through research, an efficient assembly rule and some measures to develop the dynamic characteristics are put forward, and an efficient method of dynamic characteristics analysis is summarized.