The Enhancement of Oil Delivery and Bearing Performance via a Guiding-Structured Nozzle under Oil–Air Lubrication

Abstract

The oil–air lubrication method is specifically employed for high or ultra-high-speed spindle rolling bearings. Under high-speed conditions, the air curtain formed inside the bearing cavity obstructs oil delivery, thereby limiting further increases in spindle rotation speed. To enhance oil delivery capability, a guiding-structured nozzle has been developed to concentrate the jet flow and improve penetration through the air curtain. Tests were conducted on an oil–air lubricated bearing test bench to investigate the impact of nozzle structures and oil types on torque and temperature rise. The results demonstrate that compared to conventional nozzles, the guiding-structured nozzle requires smaller optimal amounts of oil supply, indicating its superior ability to deliver oil. Further examination of oil jet patterns and droplet distributions confirms that the guiding-structured nozzle provides a more concentrated jet flow with uniform distribution and smaller droplet sizes in diameter. These characteristics contribute to highly efficient oil delivery. Additionally, synthetic oils reduce droplet size, torque, and temperature rise in mixed lubrication regimes due to their formation of an anti-friction absorption layer on rubbing surfaces.

Impact of Oil Film Dynamics on the Performance of Aeroengine Plain Bearings

“…Typically, bearing dynamics research initially focuses on determining the pressure of the bearing oil film, often investigated through solving the Navier-Stokes equation using CFD software [9][10][11][12]. Zi et al [13] performed steady-state calculations on plain and step bearings using CFD software, addressing the inertia terms and viscosity changes traditionally neglected in the Reynolds equation. Dong et al [14] assessed the effects of dynamic pressure and eccentricity on the static characteristics of bearings through studies on radial static pressure gas bearings.…”