Friction control of biomimetic bearings by electric field

A biomimetic bearing with a fail-safe braking system has been developed for installation in small, lightweight vehicles, or lifts in a production factory. The new design uses a journal bearing configuration where the rotating shaft is supported by an outer bearing lining on a soft material. The soft layer, such as is found in the articular cartilage of natural synovial joint, not only plays a role as a shock absorber but also sustains the lubricating film derived from a soft-elastohydrodynamic effect. By using an aqueous lubricating liquid, high friction occurs due to high adhesion between hydrophobic bearing surfaces at the asperity level. Once an electric field is applied between the two bearing surfaces, the adhesion at the asperity level is released, resulting in a decrease in friction. The purpose of this study was to determine the viability of a biomimetic bearing whose frictional characteristics could be controlled by an externally applied electric field.