Performance Enhancement of Hydrostatic Bearings Using Negative Lotus Structure

Hydrostatic bearings (HSBs) are widely used in precision machine tools as a kind of significant component because of the features of high accuracy, high load capacity, high stiffness and high damping. In order to improve the performance of HSB, a kind of bionic surface structure which can lead to a slip boundary, called negative lotus structure, was proposed to fabricate beneath the land of HSB. The negative structure was designed and the diameter of the nano-hole in the surface should be less than 40nm. By establishing the relationships among performance of HSB, slip length, structure parameters of simplified rotary HSB, the performance including load capacity, initial stiffness and energy consumption can be enhanced by the negative lotus structure theoretically. In order to realize the large slip length, the sample has been fabricated by the method of anodic aluminum oxide (AAO) and surface modification. The contact angle (CA) can be 148° which is close to super lyophobic measured by the glycerol droplet on the AAO sample.