Abstract: A self-lubricated sliding bearing for a rotary X-ray tube comprises a first bearing member, a second bearing member configured to concentrically enclose a portion of the first bearing member, and a lubricant comprised in a gap between cooperating surfaces of the first bearing member and the second bearing member. The cooperating surface of the second bearing member or the first bearing member comprises a first region comprising a pumping pattern configured to pump the lubricant. The cooperating surface of the second bearing member or the first bearing member comprises a second region having a modified pumping pattern or a smooth surface.

Abstract: As gantry speeds experienced in CT scanners increase, so too does the radial load force exerted on components attached to the gantry. A self-lubricating sliding bearing used inside a rotary X-Ray source of a CT scanner is particularly susceptible to increasing radial load force, because in operation, a self-lubricating bearing floats on a film of liquid lubricant. Thus, the radial load force will tend to act on the floating portion of the bearing to develop an eccentricity in the longitudinal axis of the floating portion of the bearing as compared to the longitudinal axis of the stationary part of the bearing. The eccentricity will eventually cause the floating portion of the bearing to contact the stationary part of the bearing in operation, thus limiting the load carrying characteristic of the self-lubricating sliding bearing.

Abstract: The present invention relates to hydrodynamic bearings, X-ray tubes, X-ray systems, and a method of manufacturing a hydrodynamic bearing for an X-ray tube. The rotor of a hydrodynamic bearing is supported, in steady-state operation, by the pressure of lubricant which is pumped through grooves in the rotor. When the rotor is speeding up or slowing down, the pumping force will not be sufficient to lift the rotor clear of a stationary bushing, and damage, caused by direct contact of the metal surfaces of the bearing, can occur. Providing special coatings on the bearing surfaces can ameliorate this effect.

Abstract: A self-acting, sealed hydrodynamic bearing includes a bearing shaft; a bearing bushing arranged to seal a length of the bearing shaft; a lubricant provided in the sealed length of the hydrodynamic bearing; and a bearing arrangement between the shaft and bushing. The bearing shaft and/or the bearing bushing are configured to be rotatable. The bearing arrangement includes a primary bearing surface disposed on the bearing bushing, arranged to face a secondary bearing surface disposed on the bearing shaft. The primary and/or secondary bearing surfaces includes first regions having a first fluid slip characteristic, and second regions having a second fluid slip characteristic substantially different to that of the first fluid slip characteristic. The second and first regions are in a same plane of a cross-section of the primary and/or secondary bearing surfaces, and are disposed in an interleaved pattern over the primary and/or secondary bearing surfaces.

Abstract: Hydrodynamic bearings exploit the properties of pumping action in a fluid to support a bearing load. Conventionally, the pumping action is provided by grooved surfaces in a bearing surface of the bearing. The provision of grooves leads to functional and practical problems, though. The action of grooves on a lubrication material leads inevitably to shear stress being exerted in the fluid. This has a detrimental effect on the load performance of a hydrodynamic bearing. In practical terms, the accurate manufacture of grooves is onerous. This application discusses a way of producing a hydrodynamic bearing using a portion of a bearing surface with an interleaved pattern of materials, wherein the materials have alternate high and low (or zero) fluid slip characteristics. The varying fluid slip characteristic of the surface induces a pumping effect analogous to that provided by a grooved surface.

Abstract: The present invention relates to hydrodynamic bearings, X-ray tubes, X-ray systems, and a method of manufacturing a hydrodynamic bearing for an X-ray tube. The rotor of a hydrodynamic bearing is supported, in steady-state operation, by the pressure of lubricant which is pumped through grooves in the rotor. When the rotor is speeding up or slowing down, the pumping force will not be sufficient to lift the rotor clear of a stationary bushing, and damage, caused by direct contact of the metal surfaces of the bearing, can occur. Providing special coatings on the bearing surfaces can ameliorate this effect.