Lubricating oil has a kinematic viscosity in a range of 1 mm.sup.2/S to 7 mm.sup.2/S at 40° C., has a mass average molecular weight in a range of 150 to 400, and contains 0.5% by mass or more of a high molecular weight component. The high molecular weight component has a mass molecular weight of greater than or equal to 500. A crankshaft serving as a shaft part of a compression element includes a main shaft that includes a sliding surface. In a case where the sliding surface is a single sliding surface, a length of the single sliding surface in an axial direction is a single sliding length L, whereas in a case where the sliding surface is divided into a plurality of sliding surfaces, a length of one of the sliding surfaces in the axial direction, the one sliding surface having a least length in the axial direction among the plurality of sliding surfaces, is the single sliding length L, and a ratio L/D of the single sliding length L to an external diameter D of the main shaft is less than or equal to 2.0.

A roll stand (1) includes a roll (3), in particular a backup roll, mounted via oil film bearings (2). Each oil film bearing (2) has a sealing system for sealing the oil film bearing (2) to prevent oil leakage and a coolant ingress. The oil film bearing (2) is integrated into an oil-circulating lubrication system (4), which is fluidically connected to the oil film bearing (2) via oil feed lines (5) and an oil discharge line (6). A first sensor (11) is arranged in the oil feed line (5) and a second sensor (12) is arranged in the oil discharge line (6). The two sensors (11, 12) are designed to determine the coolant content in the relevant oil volume flow.

According to one embodiment, a sliding bearing unit includes a stationary shaft including a first radial bearing surface, a rotor, and a lubricant. The rotor includes a first cylinder and a second cylinder. The second cylinder includes a second radial bearing surface and is restricted in operation so that it does not rotate relative to the first cylinder. The lubricant, together with the first radial bearing surface and the second radial bearing surface, forms a dynamic pressure radial sliding bearing.

Provided are a lubricating oil composition which contains a base oil (A) containing an ester-based oil (Al), and a polymer (B) having a constituent unit (b) derived from an alkyl (meth)acrylate, wherein the content of the polymer (B) is 0.1 to 10% by mass based on the total amount of the lubricating oil composition, the lubricating oil composition has a viscosity index of 350 or more, the lubricating oil composition has a BF viscosity at −40° C. of 4000mPa.Math.s or less, and the lubricating oil composition is used for an impregnated bearing, and an impregnated bearing impregnated with the lubricating oil composition. The lubricating oil composition has excellent lubricity in use in a wide temperature environment from a low temperature region to a high temperature region, is capable of maintaining excellent infiltration property even in an environment in which a temperature change between a low temperature and a high temperature is severe, and is suitable for use in an impregnated bearing.

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a sleeve. The structure of sleeve is formed with enlarged traps or voids in the sleeve that are disposed adjacent various rotating anti-wetting seals/seal surfaces formed between the sleeve and the shaft. The geometry of the traps is formed to retain liquid metal/lubricating fluid within the gap defined by the bearing assembly and to direct to liquid metal flowing outwardly from the gap defined between the sleeve and the shaft away from the rotating anti-wetting seals and back towards the gap. This geometry allows the centrifugal forces exerted on the liquid metal by the rotation of the bearing structure to move the outflowing liquid metal away from the rotating anti-wetting seals to significantly reduce contact of the liquid metal with the seals.

To provide a fluid dynamic bearing lubricating oil base oil which is within a suitable 40° C. and 100° C. kinematic viscosity range capable of achieving both energy saving and high bearing rigidity, and is excellent in viscosity index, heat resistance (evaporation resistance), and low temperature fluidity. Provided is a fluid dynamic bearing lubricating oil base oil containing a trimellitic acid triester compound represented by the following general formula (1)

##STR00001##

wherein R1 to R3 are the same or different and each represent a linear alkyl group having 6 to 10 carbon atoms.

To provide a fluid dynamic bearing lubricating oil base oil which is within a suitable 40° C. and 100° C. kinematic viscosity range capable of achieving both energy saving and high bearing rigidity, and is excellent in viscosity index, heat resistance (evaporation resistance), and low temperature fluidity. Provided is a fluid dynamic bearing lubricating oil base oil containing an isophthalic acid diester compound represented by the following general formula (1)

##STR00001## wherein R1 and R2 are the same or different and each represent a linear alkyl group having 6 to 10 carbon atoms.

Bearing device comprising: —a first bearing surface and a second bearing surface which are moveable relative to one another and which face one another, wherein the first bearing surface and second bearing surface are separated by a bearing gap filled with a lubricant, wherein the lubricant comprises a carrier fluid and particles which respond to magnetic or electric fields, wherein said particles are suspended in the carrier fluid in the absence of magnetic or electric fields, —one or more field generators which are embedded in the first or second bearing surface, wherein the field generators are magnetic or electric field generators configured to generate a localized magnetic or electric field which is configured to locally remove the particles from suspension by exerting a field force on the particles, thereby forming a local flow obstruction on at least one of the bearing surfaces in the form of an agglomerate of previously suspended particles, wherein the local flow obstruction is configured to locally obstruct a flow of the lubricant through the bearing gap in an obstruction zone.

A roller for deflecting or guiding a metal strip to be coated in a metal melt bath may include bearing journals disposed coaxially with one another for rotationally supporting the roller. To obtain a high coating quality while hot-dip coating the metal strip, in particular steel strip, and to increase the service life of such a roller, each bearing journal may comprise a plurality of axially spaced annular elevations that have or are formed from a plain-bearing coating. The roller may comprise a steel roller shell, and each bearing journal may include a substantially cylindrical or circular-disk-shaped connecting steel portion that extends radially in the direction of the roller shell. At least one of the connecting portions may comprise a passage opening at an end face of the roller shell. The passage may be closed by means of a gas-permeable plug element comprised of ceramic material.”

A bearing structure for an X-ray tube is provided that includes a journal bearing shaft with a radially protruding thrust bearing encased within a bearing sleeve, one of which rotates relative to the other. The stationary component, e.g., the journal bearing and/or the thrust bearing includes at least one vent groove formed therein that improves the ability of the journal bearing structure to enable gases trapped by the liquid metal within the bearing assembly to escape through the vent groove to the exterior of the X-ray tube. By adding a strategically located channel or vent groove of sufficient size in at least one of the journal bearing or the thrust bearing, the pressures resisted by the seal created between the liquid metal and the vent groove(s) in the bearing components is significantly reduced, allowing escape of the gases to avoid detrimental effects to the operation of the X-ray tube, while maintaining the load carrying capacity of the bearing assembly.