| Currently the performance and reliability of hydraulic components are the bottlenecks that hinder the development of the domestic hydraulic technology, yet the hydraulic pump is a core component of the hydraulic system, and its performance directly affects the operating characteristics of the system, so setting up its test system with a good performance is particularly important. Basically the traditional pump-test is non-power recovery system which means using the dissipative elements to load, and that all the energy turn into heat dissipation, and it will bring an additional large cooling system. The system energy consumption and test costs are so high that it is almost impossible to achieve the long life of high-power pump-test. Yet the power-recovery test system can bring about more than 60% energy recovery, energy-saving effect is remarkable. Therefore, the system has much lower installed power, and can be laid out flexibly. Because of above merits, power-recovery pump-test systems have been the concern of people, and applied in more and more extensive range. However, research of the power recovery system of hydraulic pump-test is at the initial stage. In the test system, there are still problems to solve, such as improving regulating performance of test load, and reducing the effects due to pumps'pressure fluctuation, matching the system better to improve the recovery efficiency, and completing and refining test functions. Therefore, a novel design of power-recovery pump-test system has been proposed, and its performances have been studied basing on a main pump, which is researched and designed recently and used in concrete pumps. The main tasks accomplished in this dissertation are as follows:1. Review of the existing hydraulic pump-test system and its features. Based on the test content and requirements of the hydraulic pump-test system, many aspects are analyzed and summed up, such as types and working principles. Then be pointed out major defects, and definite the working principles and property requirements of the power-recovery pump-test system. 2. Design of the power-recovery hydraulic pump-test system and its performance analysis. Through theoretical analysis, performances of the load pressure's regulation methods, such as frequency control, varying displacement of the motor, external filled oil, are compared. Through an intensive study of the flow and pressure fluctuation, an improvement scheme is proposed. Power-recovery pump-test system is designed, and a detailed analysis and calculations are carried out, about the matching requirements and recovery efficiency.3. The establishment of simulation model and simulation analysis of the dynamic performance have been done. Based on Power Bond Graph Method, the bond graph model, the mathematical model and the Simulink simulation model have been established. After substituting the simulation parameters into it, the load pressure regulation characteristics, pressure fluctuation, impact test characteristics are simulated and researched.4. Experiments on the power-recovery pump-test system. Through the experiment analysis about loading and experimental characteristics of the system, it is further verified that the power-recovery pump test system has a good energy-saving efficiency and test performance. |
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