Design And Study Of Low-Power And Miniature2D Eletro-Hydraulic Proportional Directional Valve

As a supplement to electro-hydraulic servo valve and switch valve, electro-hydraulic proportional valve is more and more widely used in industrial production with the fast development of proportional solenoid technology in recent days. Based on the basic working principle of2D valve that axial movement of the spool is associated closely with its rotational movement, combined with the control characteristic of proportional solenoid, this paper proposes a design of low-power and miniature2D electro-hydraulic proportional directional valve. In the valve, the linear motion of proportional solenoid armature is transformed to the rotary motion of spool by the new transmission called pressure torsion coupling. The rotary motion of spool will cause differential pressure changes of the two end cavity, which will drive the spool move axially. At last, the axial movement of the proportional solenoid armature is followed by the axial movement of the spool. Because of the large force-torque amplification coefficient of pressure torsion coupling, the spool can be easily driven by the proportional solenoid with small output force, which provides an effective way for proportional valve to achieve the design goal of low power consumption and small size.This thesis has designed and studied the low-power and miniature2D eletro-hydraulic proportional directional valve. Related sections are as follows:In the first chapter, the research background is described at first. Then, the history of electro-hydraulic proportional valve, as well as the domestic and foreign research of electro-hydraulic proportional valve, is introduced in detail. At last, the significance and the main content of the paper are summed up.In the second chapter, the working principle of the screw mechanism in2D servo valve is represented. For the structural feature that this kind of mechanism can not be directly transfered to proportional valve, a new low-power and miniature proportional valve design called2D electro-hydaulic proportional directional valve has been proposed. Then, the working principle of2D electro-hydaulic proportional directional valve is explained. At last, the design of its key elements and selection of some components are described. In the third chapter, the mathematical model of2D electro-hydaulic proportional directional valve is established, followed by the derivation of transfer function.In the forth chapter, the Simulink is used to analyze the the dynamic characteristics of2D electro-hydaulic proportional directional valve. The influence caused by changing parameter to the dynamic characteristics of the system is analyzed. These influence parameter incude the initial bow height and radius of high and low pressure holes, system pressure, the length of sensitive cavity, the angle and effective radius of pressure torsion coupling.In the fifth chapter, an experiment system is built to analyze the input-output characteristics of pressure torsion coupling and the no load flow characteristics of2D electro-hydaulic proportional directional valve. Experimental results show that the pressure torsion coupling has good input-output characteristics, and the flow can achieve34.5L/min under21Mpa system pressure when the input current of proportional solenoid is0.24A.In the last chapter, the summarization of this thesis and the prospect of this research are given. The research results show that the design of2D electro-hydaulic proportional directional valve in this paper provides a good solution for the proportional directional valve to achieve the goal of low power consumption and small size. So, it is worth studying in depth.