Compliant foil hydrodynamic fluid film radial bearing

摘要

A compliant foil hydrodynamic fluid film radial bearing is disclosed which is comprised of a cylindrical rotor, fluid foil(s), spring foil(s), and a foil retaining cartridge. The cartridge has circumferentially undulating cam shaped lobes or has circumferential ramps and joggles that induce the spring and fluid foils to form converging fluid-dynamic wedge channels which compress and pressurize the process fluid and diverging channels which draw in makeup fluid. A spring foil is formed as a thin, flat sheet having chemically etched slots of a pattern that causes cantilever beams to stand erect and function as springs when the foil is bent to install in the cartridge. When a single foil is used in lieu of a plurality of foils made up of segments, that foil is preloaded away from the rotor by bending stresses in the foil that are induced when the foil is bent to fit into the cartridge. Additional forces to preload the foils away from the rotor can be applied to the ends of the foils by a circumferential preload bar in the aperture of the cartridge. This combination of preloading techniques results in low starting torque, low lift off speed and small sway space. The fluid foil, when used with the cam shaped cartridge, is vented in the area of the diverging channels to admit the working fluid, and has V-shaped grooves chemically etched into the outer surface of the foil near each end to tailor the foil's bending stiffness.