Design of Slip Boundary Produced by a Lotus Structure Applied to a Hydrostatic Bearing

Abstract

Hydrostatic bearings (HSBs) are widely used in large-size precision machines because of the features of high load-carrying capacity, high stiffness, and high accuracy. This study focuses on enhancing the performance of HSBs by modifying the boundary condition from non-slip to slip. The lotus structure underneath the bearing land was designed to achieve this modification based on the developed theoretical model and simulation results. Three major theoretical works were conducted: (1) modification from the non-slip boundary condition to a slip condition; (2) establishment of the relationship between the slip length and the height of the lotus structure with various area fractions of oil–air interface; and (3) design of the lotus structure to create the required slip length. Finally, the microchannel and the biomimetic lotus structure were fabricated for the purpose of simulating the slip boundary condition on the surface of the bearing land. Superior bearing performances and reduced energy consumption were obtained by increasing the slip length.