Research on Contact Performance and Friction Force of VL Seal of Aviation Actuator Under High Pressure Conditions

To elucidate the contact performance and friction force variation characteristics of VL seals for aviation actuators under high-pressure conditions, this study adopted a fluid–structure interaction (FSI)-coupled finite element model to analyze the maximum contact pressure and contact width and their respective variation trends across varying oil pressures and reciprocating velocities. Subsequently, friction force tests of the seals were conducted under matching operating parameters, and the friction coefficients of polytetrafluoroethylene (PTFE) were measured and compared under different normal pressures. The results demonstrate that the friction force of the seals during both extending and retracting strokes increases with rising oil pressure, which is highly correlated with the theoretically predicted conclusion that the seal contact width expands as oil pressure increases. Further analysis confirms that reciprocating velocity exerts no significant influence on the aforementioned variation trends. This study provides a critical basis for the selection and optimal design of VL seals used in high-pressure aviation hydraulic actuators.