Optimization And Design Of Rotary Control Valve With Anti-Load Fluctuation Function

As the traditional machinery to replace the labor of human being, crane can move weights from one place to another. It is widely used in industrial transportation and civil buildings. Hydraulic transmission is widely used in construction machinery due to its advantages of big transmission ratio and large power, easy operation and long lifespan. The rotary system is an important part of hydraulic system of crane. The rotary inertia is large when it working with weights, so the pressure and flow rate will fluctuate if there are no buffering measures. It will cause fatigue damage to machine parts and reduce their service life. The load variation range of rotary system is large when the crane works with weights. The change of load will cause the instability of the rotation speed. There are not many rotary control valves at home and abroad, so it is necessary to do deep research on it to develop a superior performance of rotary control valve.Taking the rotary control valve of automobile crane as the research object, this thesis analyzes the existing problems of rotary control valve with anti-load fluctuation in the real vehicle, and gives the optimization scheme. By setting throttling groove shape and flow area of six-way valve, the flow rate of optimized rotary valve in small opening area increases. By adding the buffer valve and adjusting the screw damping to get the appropriate buffer pressure, starting and braking delay reduce and braking stability improves. The mathematical model of rotary control valve is established, and the simulation research is carried out by using software AMESim and Simulink.The research content of this paper is divided into 7 chapters, and the contents of each chapter are briefly described as follows.In chapter 1, it contains background introducing and research points. The function, classification and the hydraulic system of crane are briefly introduced, and then present the research situation of the rotary control valve. In last, discussing the significance and research methods, and determining the main contents of the research.In chapter 2, firstly, the working principle of anti-load fluctuation rotary valve is introduced. Then its problems in real vehicle test are analyzed. Third, the simulation model used software AMESim is established to reappearance problem conditions.In chapter 3, the mathematical model of the six-way valve controls hydraulic motor is established. The whole simulation model is built used software Simulink. The initial conditions in simulation are setting reasonably to accomplish the dynamic and steady simulation.In chapter 4, the reasons of the problems in vehicle test are analyzed. Then redesign the valve with simulation model. The flow area ratio of meter-in port and bypass port is changed, and the new type of buffering valve is introduced.In chapter 5, the bench test of optimized rotary valve is done. Its steady-state characteristics, dynamic characteristics and load fluctuation characteristics are analyzed. The advantages and disadvantages of the optimized rotary valve are analyzed compared with the original valve.In chapter 6, the vehicle test of the optimized rotary valve is done. Through analyzing test data, it is verified that the optimized rotary valve has the characteristic of anti-load fluctuation, dynamic opening fast and braking stability.In chapter 7, the work of this thesis is summarized, and the future research is prospected.