Research on Leakage Characteristics and Optimal Design of Electro-Hydraulic Proportional Directional Valves

Internal leakage directly affects the efficiency and positioning accuracy of electro-hydraulic proportional directional valves. This study establishes an annular-clearance leakage model incorporating eccentricity, pressure-dependent viscosity, and pressure-induced deformation, and develops a main-stage spool valve model in Simcenter AMESim 2021.1. Single-factor simulations and an L18 orthogonal design are used to investigate the effects of six key parameters. The results reproduce the approximately cubic dependence of leakage on clearance height and the theoretical 2.5-fold full eccentricity to concentric leakage ratio. Under controlled single-factor conditions, leakage increases with system pressure, clearance height, eccentricity ratio, and spool diameter, and decreases with valve lap magnitude and dynamic viscosity. The full L18 data yield the descriptive range order valve lap > eccentricity ratio > clearance height > dynamic viscosity > spool diameter > system pressure. An influence diagnostic shows that this ranking is sensitive to high-response runs and should therefore be treated as exploratory. The lowest leakage observed among the 18 simulations is 0.0008 L/min. These findings provide simulation-based guidance for parameter selection and leakage control in proportional valves.