| Material Handling now plays an important role in the national economy, cranes—the important handling equipment are accordingly used more and more widely in the modern production process. As the rapid development of electric power, petroleum, chemical and transportation, Cranes'species and their market needs are increasing.Now hydraulic construction is widely used in crane driver. Slewing mechanism is an important institution of crane. The rotating mechanism has the characteristics of large inertia when operating, so it has a greater pressure shock,which would affect the working life of hydraulic components, easily damage pressure sensor and cause machine vibration, resulting in poor fretting action, making the working efficient lower, thereby constraining the rotation system performance. Reasonable hydraulic oil can improve operational efficiency, improve overall performance, even improve working conditions and reduce the heat etc. Slewing operations should be as smooth as possible and have shortter braking time, with pressure shork of starting, braking, reversing smaller when operating. In order to meet these requirements, we need to make special slewing mechanism analysis of the hydraulic oil. Only by understanding the dynamic characteristics, the various parameters of the system can be reasonably matched. In the past, crane hydraulic system design and evaluation of analysis on manufacturers of cranes in our country generally are based on people's experiences and draw the necessary products in order to set the static design of the main consideration, and through experimental discovery in the prototype problem. Simply the use of experimental method, not only spend a lot of energy and material resources, but also sometimes change the parameters or conditions are difficult, even impossible. The traditional theory of transfer function analysis is cumbersome and even a little mistake could cause actual results far. But the use of simulation analysis method can simplify this complex problem. This article is based on the actual project of the school and the enterprises of the "mobile crane hydraulic control circuit product testing and evaluation system development", the hydraulic system of truck crane slewing conducted a study similar systems present a common problem as the starting point on how to turn Agency operations pressure steady, shorten the braking time and reduce the pressure when starting, braking and reversing.1. Through the analysis of slewing mechanism, the establishment of a mathematical model about hydraulic control system of the hydraulic circuit, this paper analyzes the parameters that have an impact on the hydraulic control system.2. Based on simulation model of slewing hydraulic system, to experiment on the 50t truck crane and measure the pressure dynamic curve in two conditions of the slewing hydraulic system; to compare simulation results with experimental results and modify the parameters to make the model more realistically reflect the actual conditions; to verify the correctness of the simulation model.3. On conducting simulation analysis on simulation model of AMESim, to analyze the moment of inertia, load resistance torque, buffer valve springs, cushion valve opening area, the pump flow's impact on slewing mechanism in starting rotation, braking and reversing; to analyze how to slow the pressure fluctuation of the slewing mechanism in starting and braking and shorten the braking time, to improve the overall performance and the safety of turning operations.The analysis of the crane hydraulic system provides a reasonable plan which is very important to improve the overall performance of cranes. I hope the results of this study can also provide some reference value for the similar products' design and evaluation. |
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