| The multi-way valve is widely used in lifting transport vehicles, coal mining machinery and engineering machinery, it's performance will have greatly influence on the control characteristics and work efficiency of the equipment. Due to the continuous development of industrial modernization, the stability and system efficiency of the construction machinery have a higher demand, so that the existing multi-way valve operating characteristics can not meet the actual need. At present,there are many problems in the domestic multi-way valve: the working flow is unstable, the operating force is not easy to control, and the system efficiency is low. In view of these problems,it is very important to study on the static performance and dynamic performance of the multi-way valve. This thesis is based on the cooperation project of Hunan Honghui Science&Technology Co., Ltd and Zoomlion Engineering Crane Co., Ltd. It has developed a multi-way valve for crawler crane. The theoretical analysis, simulation analysis and experimental verification are carried out to improve the performance of the multi-way valve.First, the theoretical design, calculation and analysis of the multi-way valve are carried out, and the structural characteristic and working principle are expounded in detail. The main dimension and parameters of the multi-way valve are determined by design calculation. The leakage of the multi-way valve and the movement of the stem are calculated and analyzed. According to the analysis of pressure compensation and the efficiency analysis of the load sensitive system, it can be seen that the pre-valve parallel pressure reducing valve can make the moving speed of the actuator not be affected by the changing load and improve the working stability of the system. The throttle valve port of the multi-way valve is designed, which adopts the combination of U shape and UU shape orifice. Through the calculation and analysis, it used Matlab to draw it's flow area curve. the flow area with the displacement is slow and then fast,it can achieve the flow of multi-level throttle control.The system simulation model of the multi-way valve of crawler crane is established by AMESim software. The leakage, pressure loss, flow regulation characteristic and load sensitive characteristic are simulated and analyzed, the parameter of the working stability on the multi-way valve, the spring pre-tightening force of the pressure compensation valve and the diameter of the feedback oil port are simulated and optimized. By reducing the spring preload of the pressure compensator and the diameter of the feedback damping port, the fluctuation of the system pressure flow can be reduced, therefore, it improved the smoothness of the multi-valve operation.Finally, in order to verify the feasibility of the design scheme and validate the simulation results, the performance test of the multi-way valve is carried out on the hydraulic comprehensive testing bed. The characteristic of pressure resistance,commutation performance, pressure loss and fretting of the multi-way valve were tested, the technical indexes of the test meet the design requirement. the installed test was carried out on the ZCC550H crawler crane, the test under different conditions that showed the performance of the multi-way valve was relatively stable,and it had good control characteristics. |
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