Abstract:In order to improve the sealing performance of hydraulic thruster, a combined seal composed of sliding ring and O-ring was designed. The finite element simulation of the sealing structure was carried out by using the loading method of fluid pressure osmotic load, and the influence rule of single factor of the structural parameters of sliding ring on the sealing performance was obtained. The sealing performance of piston under the combined action of structural parameters of sliding ring was analyzed by orthogonal test. The results show that the influence of bottom thickness, side width of slip ring, height of slip ring and radial seal clearance of piston on contact pressure of dynamic seal surface is decreased in turn. When the slip ring height is 6.5 mm,the side width of slip ring is 2.65 mm,the thickness of bottom of slip ring groove is 0.7 mm and the radial clearance of single side is 0.25 mm,the maximum contact stress of the new sealing structure is 245% higher than that of conventional O-ring structure. The contact stress of the dynamic sealing surface in the new sealing structure is significantly higher than that of the conventional O-ring structure,which improves the sealing performance of the hydraulic thruster.