Hydraulic Power Closed System Design And Load Characteristics

Loading test for mechanic transmission components and transmission system is one of the most important production links to guarantee performance. Power open loading system is the loading mode that is used in laboratory always. By using this mode, all of the energy is converted into heat when loading. Not only a large amount of energy is dissipated, but also it doesn't meet the demand of actual conditions of the test (e.g. motor test).For high-power transmission system (e.g. gearbox for wind turbine), it is impossible to do loading test and life test, because of the input power and dissipation energy. Therefore, power recovery loading method must be used. Power recovery system, also called power close system, has three main kinds, including mechanic power close system, electric power close system and hydraulic power close system. Compared with other two kinds, there are a lot of advantages by using hydraulic power close system, such as structure is simple, layout is flexible, generality is strong, application, installation and maintenance is very convenient. It will be the main mode of transmission test bench with power closed in future. At present, the research on composition structure, working principle and regulation characteristics is still in primary stage. There are a series of problems to be solved in a number of ways, e.g. control of load torque, improvement of power recovery rate of system. Therefore, it has important practical significance to make a study on hydraulic power close system.Detailed theoretical analysis and practice in basic theory and working principle of hydraulic power recovery have been made in this paper. In order to provide valuable theoretical guidance for further study, some research work has been done, including the following aspects:1.The basic theory of hydraulic power recovery system is summarized. Basic on the results of current research, many aspects of hydraulic power recovery system, such as types, working principle and structure characteristics, are summed up systematically, and overall analysis of a series of technical problems have been made, such as establishing methods of loading torque and regulation mode of system pressure. Then, design principle and method have been defined.2.Schemes of hydraulic power recovery system are designed. Mechanical compensation and hydraulic compensation are the two main kinds of hydraulic power recovery system, and it has a lot of features in composition structure and regulation characteristics itself. For systematic research on hydraulic power recovery, two kinds of hydraulic system solutions are designed, and a detailed calculation and analysis of working principle is carried out, containing flow matching, torque matching and power recovery rate of system.3.System simulation models are built, and dynamic simulation research has been done. By adopting Power Bond Graph Method and Simulink Toolbox of MATLAB, after entering simulation parameters, dynamic simulations of several working conditions are carried out. Then the results are analyzed for verifying the theory.4.Hydraulic power recovery test bench is built. After the practical research on loading regulation characteristics and power recovery rate of system, the correctness and feasibility of the theory of hydraulic power recovery system are verified further.