A Pilot Stage Digital Electrohydraulic Servo Valve with Variable Area Gradient

Abstract

The invention discloses a pilot stage digital electro-hydraulic servo valve with variable area gradient. A high-speed switch valve is respectively installed in the control chambers on both sides of the electro-hydraulic servo valve to form a pilot stage; the digital servo controller utilizes negative feedback to Two high-speed on-off valves are controlled; through the control of the high-speed on-off valve, the pressure difference between the two control chambers of the spool is formed to control the movement of the spool; The edge of the orifice is designed to have a continuously variable area gradient, so that the area gradient of the orifice increases with the increase of the displacement of the spool. It can be seen that the pilot stage of the present invention adopts two high-speed on-off valves of the same type, combined with a digital controller to realize valve core displacement control, which not only has good dynamic characteristics, but also improves the anti-pollution ability of the servo valve, thereby reducing the failure rate; The design of the edge of the orifice of the sleeve can improve the zero resolution and flow control accuracy, and at the same time can achieve a larger rated flow.

Description

technical field [0001] The invention relates to the technical field of fluid transmission and control, in particular to a pilot-stage digital two-stage electro-hydraulic servo valve with variable orifice area gradient. Background technique [0002] The sleeve of the traditional electro-hydraulic servo valve adopts a full-circumference throttling groove. The radius of the throttling groove ring is constant, and the orifice area and the displacement of the valve core are in a linear relationship, that is, the gradient of the orifice area is constant, which also means The flow rate of the servo valve has a linear relationship with the displacement of the spool, that is, the flow gain is constant. When doing servo control, the spool mainly works near the zero position, so the zero position resolution will affect the tracking control accuracy. When the maximum displacement of the spool is constant, if the rated flow rate of the valve is large, the gradient of the orifice area an...

AI Technical Summary

Problems solved by technology

The nozzle flapper servo valve has high requirements on oil cleanliness, poor anti-pollution ability, and the nozzle is easy to clog; while the jet tube type servo valve has better anti-pollution ability, but the model is more complicated, and the valve characteristics are difficult to predict, mainly determined by experiments , debugging is difficult, and the inertia of the jet tube is large, and the dynamic characteristics are poor

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