Characteristic Progress and New Solutions for Nozzle Baffle Type Electro-Hydraulic Servo Valve

Background: This article outlines the working principle of the nozzle baffle type electro- hydraulic servo valve and analyzes the progress of research on its characteristics more fully. Objective: Firstly, it summarizes the research progress on the characteristics of the cavitation phenomenon, which is a common failure of nozzle baffle type electro-hydraulic servo valves; secondly, it comprehensively discusses the structural characteristics of nozzle baffle type electrohydraulic servo valves: moving-iron torque motors and moving-coil torque motors, as well as the progress of the research on the characteristics of the power-stage valve spools and direct-injection valve spools. Methods: It suggests to the readers other optimization methods that can be made for the cavitation phenomenon in the future, and brings innovative ideas for the readers in terms of moving-iron vs. moving-coil torque motors and other aspects that can be improved for the power-stage spools vs. direct-injection spools. Again, for the typical technical problems of nozzle baffle type electrohydraulic servo valves, we have searched and organized the related technical patents at home and abroad and clearly outlined the current improvements for nozzle baffle type electro-hydraulic servo valves. Results: Through the discussion of related articles and patents, it is found that although many methods have been proposed at home and abroad to address the shortcomings of the nozzle baffle type electro-hydraulic servo valve, it still has a high failure rate and has not been comprehensively solved, there is still a lot of room for optimization. Conclusion: Finally, the new solutions proposed for the performance deficiencies of nozzle baffle type electro-hydraulic servo valves are summarized, and the future development trend of nozzle baffle type electro-hydraulic servo valves is predicted and outlooked.