Structural Optimization And Characteristic Simulation Of Combined Hydraulic Damping Elements

In the load sensitive system of the quantitative pump,the main pump itself can not adjust the flow.In order to realize the pressure compensation and flow regulation,the system needs to set the bypass type pressure compensation flow control loop and the flow control valve.In the dynamic process of the flow control valve to achieve pressure balance,the control oil path from the load end will inevitably produce pressure oscillation,which affects the constant pressure difference of the inlet and outlet of the multiple valves.In order to ensure that the control pressure difference of the flow control valve is constant,the output flow of multichannel valve is not disturbed by the external load and the jitter of the working device is reduced,the damping element should be set up in the system.The purpose of this paper is to design a combined hydraulic damping element.The damping element is composed of adjustable flow mouth and fixed damping hole.By dynamic automatic adjustment,the size of the flow mouth can be adjusted and the feedback end of the flow control valve is reduced to control the pressure fluctuation of the oil path,thus ensuring the smooth movement of the actuator.The main contents of the thesis are as follows:(1)Firstly,the working principle of the load sensitive system of the two branches of the quantitative pump and the function of the damping element in the control loop are analyzed in detail,and the dynamic mathematical model of the two series damping is established.The influence of the structure parameters of series damping on the control pressure of oil circuit is obtained by solving differential equation with Matlab.(2)determining the performance index of the damping element and the orifice form of the valve core,designing the whole structure of the damping element,and designing and calculating the main dimensions of the damping element.The dynamic characteristic equation of damping element spool is established,and the dynamic characteristic of damping element is simulated by simulink.The influences of orifice diameter,spring stiffness,core mass and half cone angle on core displacement were analyzed respectively.(3)get the channel model open pressure and velocity distribution nephogram under different orifice in Fluent.Through the comparison of damping channel images in memory pressure impact and cavitation.Then from the section of the slot size,than the bottom areaof the valve core,the fixed orifice length to diameter ratio of three aspects of structural damping element improved.And through the orthogonal test method to obtain the best combination of parameters.(4)AMESim is used to simulate and analyze the two branch load sensitive system of the hydraulic damping element and the quantitative pump.The influence of the damping element's structural parameters on the damping element itself and the pressure flow characteristics of the LS control oil path is studied respectively.