Effects of striated texturing on pivoted gas sliders

Abstract

The paper is a study of effects of striated, transversely oriented texturing on pivoted gas lubricated sliders. Unlike the author's recent works on texturing, in the present case the complete slider surface is textured. To simplify the analysis, the high bearing number approximation has been used to calculate load carrying capacity and stiffness for just a few macro-geometries. The averaging operators derived for incompressible fluids are also valid for gases [Tønder K. Theory of effects of striated roughness on gas lubrication. In: Proceedings of the JSLE international tribology conference, Tokyo, Japan; 1985. p. 761–6; Weissner S, Tønder K, Talke FE. Surface roughness effects in compressible lubrication. In: Proceedings of the Austrib’98 international tribology conference, Brisbane, Australia; 1998. p. 111–22.]. These have been used here. It is seen that texture in the form of longitudinal furrows is not beneficial for very thin films, when the high bearing number approximation is acceptable. As in Ref. [Tønder K. A simplified assessment of the performance of differentially textured hard disk sliders. Tribol Int 2005;38(6/7):641–5], the study is limited to transverse grooves. The performance of pivoted textured sliders has been compared with that of more conventional designs. Plain textured geometries are found to have stiffness properties somewhat poorer than those of most current slider designs. However, they do possess realistic stiffnesses; this makes the concept of texturing standard slider surfaces rather appealing. It seems probable that texture may provide some damping. Finally, it is suggested that texturing liquid lubricated bearings may, under certain conditions, prevent bearing failure caused by bubble-induced compressibility of the lubricant.