Research on double-layer oil film performance of flexible pivot tilting pad bearing

Purpose The purpose of this paper is to enhance the lubrication performance and load capacity of the bearing. To achieve this goal, the traditional singlelayer oil film support is transformed into a hybrid bearing featuring inner and outer double-layer oil film support with a flexible pivoted tilting pad. The inner oil film, the outer oil film and flexible pivot form a synergistic mechanism of lubrication, improvement of carrying capacity, and stabilized oscillation, addressing the critical challenges of pad back wear, excessive oscillation and insufficient load capacity under high-speed and heavy-load conditions. Design/methodology/approach The inner and outer oil film thickness equation, Reynolds equation, flow continuity equation and pad torque balance equation of the double-layer oil film flexible fulcrum tilting pad hybrid bearing are established. The influence of preload coefficient on the lubrication performance of bearing is studied. Findings The results show that after considering the double-layer oil film effect, the swing angle of the tilting pad decreases, the pressure of the inner oil film decreases, but the decrease amplitude is less than the increase amplitude of the outer oil film, and the overall bearing capacity of the bearing shows an increasing trend. The larger the preload coefficient is, the larger the oil film pressure of the inner and outer layers is, the higher the bearing capacity of the bearing is, and the smaller the friction coefficient is. Originality/value The new structure integrates a flexible pivot with a double-layer oil film on the pad back, where the inner oil film sustains loads through a combination of hydrodynamic and hydrostatic methods, the outer oil film serves the dual functions of load-bearing and reducing friction, the flexible pivot reduces stress at the pivot point. The research has great significance for improving the lubrication performance of tilting pad hybrid bearing and perfecting the lubrication theory of tilting pad hybrid bearing.