Advancements and Patent Trends in Deflector Jet Tube Electro-Hydraulic Servo Valves

Deflector plate jet servo valves are mostly used in high-temperature and high-pressure situations, and are widely used in both military and industrial applications. The deflector plate servo valve does not need a winding oil supply pipe, which overcomes the vibration that may occur in the structure. Although the deflector jet tube-type electro-hydraulic servo valve is widely used, its structure is complex, involving a large volume, which makes it easy to produce noise and cause oil leakage and other problems; its characteristics are prone to be affected by the temperature. Also, due to the complexity of its internal flow field, it is prone to erosion and wear phenomena. This paper, thus, aimed to overcome these shortcomings by collecting data from the works and patents that have focused on improving these characteristics. It has been found that a large number of scholars have analyzed the characteristics of the pre-stage flow field by establishing models and fluid simulations, focusing on the thermal characteristics under the influence of temperature and the internal problems under the influence of erosion and wear, and put forward a large number of structural optimization and improvement schemes. In view of the pressure and flow output of the deflector jet tube type electro-hydraulic servo valve, the difficulty of structural processing, the difficulty of structural assembly and adjustment, the weakening of structural strength, the influence of component wear and the interference of deflection plate displacement, etc., we have summarized the relevant patents both at home and abroad, and discussed how to improve the deficiencies of the deflector jet tube type electro-hydraulic servo valve. By summarizing a large number of articles and patents, it has been found that the deficiencies of the deflector jet tube type electro-hydraulic servo valve still need to be explored and overcome by more scholars. Domestic and foreign research on the characteristics of the deflector jet tube type electro-hydraulic servo valve is relatively deep, but the research on some key technologies of this valve is still insufficient and needs to be conducted in the future.