Fundamental Study on Oil Leakage from Tapered Seal at Ends of Fluid Film Bearing for Precision Equipments

(Experimental Study on Oil Leakage from Tapered Seals)

Abstract

Fundamental experiments on fluid leakage from tapered seals due to sleeve rotation were carried out. The apparatus was designed so that the surface tension, which generates a sealing function, acts effectively in terms of size and accuracy similar to its behavior in an actual device. The shapes of the interface (boundary surface of two kinds of fluids) at several rotational speeds were measured with an ultra-focus laser microscope, and the features of fluid leakage were observed with a high-speed camera. The experimental results of the positions of the bottoms of the interface coincided comparatively well with the theoretical ones. We also verified that the threshold speeds in the experiment on fluid leakage could broadly be estimated by using the theoretical ‘ultimate’ and ‘triggering’ critical rotational speeds of the sleeve.