Simulation analysis and optimization of pilot type electro-hydraulic proportional directional valve based on multi field coupling

The pilot-operated electro-hydraulic proportional directional valve is widely used in complex and precision engineering fields. Its operational stability and reliability determine the overall performance of the hydraulic system. During the working process of the pilot-operated electro-hydraulic proportional directional valve, the spool is deformed due to the influence of pressure and temperature, resulting in problems such as clamping or stagnation. In order to solve this problem, this study uses the fluid-solid-thermal coupling simulation method to analyze the flow field characteristics and thermal deformation of the spool with different structural throttling grooves, and optimizes the U-shaped throttling groove structure. The results indicate that as the valve opening increases, the front section of the throttling groove becomes the primary region where the maximum radial deformation of the spool occurs. In this paper, the steady-state flow force of the valve core is taken as the measurement standard, the constraint range of the structural parameters is determined, and the radial thermal deformation is included in the optimization analysis of the structural size. It's verified that the optimized flow characteristics are improved by about 32 % compared with that before optimization, and the maximum steady-state flow force after considering thermal deformation is reduced by about 4N compared with that before optimization. This provides an important design basis and reference for the structural design and optimization of the pilot electro-hydraulic proportional directional valve.