A turbomachine comprising a turbomachine shaft for rotation about an axis and for supporting a turbine wheel at one end of the turbomachine shaft; and a bearing housing having a wall defining a bore in which the turbomachine shaft is received with a substantially annular clearance, the turbomachine shaft being supported for rotation in the bore by at least one journal bearing located within the annular clearance. A surface of the turbomachine shaft which radially underlies the or each journal bearing has a surface roughness (Ra) of less than 0.15 microns and the or each journal bearing comprises a bronze alloy incorporating bismuth in an amount of up to around 6 wt %.

A damping arrangement (1) for damping radial vibrations in a rotating shaft (2), the damping arrangement (1) comprising at least one first damping element (3), at least one second damping element (4), and a bearing arrangement (5) operably engaging the first damping element (3) and the second damping element (4). The bearing arrangement (5) comprises a first bearing member (6), a second bearing member (7), and a reference (8). The first bearing member (6) is rotatably mounted on the shaft (2) so that radial movement of the shaft (2) is transferred to the first bearing member (6), and is operably connected to the second bearing member (7) by the first damping element (3) and by a first steering structure (9). The first steering structure (9) allows only reciprocating movement of the first bearing member (6), and the shaft (2), in a first radial direction (D1), and the first damping element (3) dampens the reciprocating movement in the first radial direction (D1) with respect to the second bearing member (7). The second bearing member (7) is operably connected to the reference (8) by the second damping element (4) and by a second steering structure (10) allowing only reciprocating movement of the second bearing member (7), the first bearing member (6), and the shaft (2), in a second radial direction D2. The second damping element (4) dampens the reciprocating movement in the second radial direction (D2) with respect to the reference (8).

There are provided a copper alloy for a slide bearing and a slide bearing, which can prevent Mn—Si primary crystals from causing seizure. The copper alloy for a slide bearing and a slide bearing according to the present invention contain 25 wt % or more and 48 wt % or less of Zn, 1 wt % or more and 7 wt % or less of Mn, 0.5 wt % or more and 3 wt % or less of Si, and 1 wt % or more and 10 wt % or less of Bi, the balance consisting of inevitable impurities and Cu, wherein there exist, in a sliding surface on which a counter material slides, Bi particles having a circle equivalent diameter larger than the average circle equivalent diameter of Mn—Si primary crystals and Bi particles having a circle equivalent diameter smaller than the average circle equivalent diameter of the Mn—Si primary crystals.

A turbocharger is provided with an improved bearing which is formed as a floating ring bearing or a semi-floating ring bearing having a conical or hemispherical shape which supports both journal and thrust loads. The floating ring bearing may have conical floating ring bearings (70), (100), (180) that define inner and outer conical bearing surfaces (71), (108), (185) and (72), (109), (186) which cooperate on the inside with corresponding conical journals (75/76), (111/112), (187/188) that rotate with the shaft (53), and cooperate on the outside with a stationary bearing housing (52) to form inner and outer fluid films. Alternatively, the floating ring bearing may have a pair of hemispherical floating ring bearings (85), (140), (210) that have hemispherical inner and outer bearing surfaces (86), (144), (211) and (87), (145), (212) which form inner and outer fluid films. A semi-floating ring bearing may also be provided with these structures.

A turbocharger is provided with an improved bearing which is formed as a floating ring bearing or a semi-floating ring bearing having a conical or hemispherical shape which supports both journal and thrust loads. The floating ring bearing may have conical floating ring bearings (70), (100), (180) that define inner and outer conical bearing surfaces (71), (108), (185) and (72), (109), (186) which cooperate on the inside with corresponding conical journals (75/76), (111/112), (187/188) that rotate with the shaft (53), and cooperate on the outside with a stationary bearing housing (52) to form inner and outer fluid films. Alternatively, the floating ring bearing may have a pair of hemispherical floating ring bearings (85), (140), (210) that have hemispherical inner and outer bearing surfaces (86), (144), (211) and (87), (145), (212) which form inner and outer fluid films. A semi-floating ring bearing may also be provided with these structures.

A bearing housing (12) for a turbocharger having a rotatable shaft (14) passing through the bearing housing (12) with journal bearings (30) having tilting pads (40) for supporting the rotatable shaft (14) in the bearing housing (12). The tilting pads (40) may have oil supply holes (50) through each pad (40) to direct lubrication to each pad surface (44). The journal bearings (30) preferably have a circumferential groove (52) on an outer surface of the bearing aligned with the oil supply holes (50) to help feed oil to the oil supply holes (50).

The cam follower roller device comprises a body, a shaft mounted on the body, a roller mounted on the shaft and able to rotate, and a plain bearing interposed radially between the shaft and the roller. An outer surface and/or an inner surface of the plain bearing comprise a plurality of cavities. The ratio of the sum of the surfaces areas of the cavities to the total surface area of the outer surface, or of the inner surface, in which the cavities are formed is between 2% and 40%. The cavities have a depth between 0.5 μm and 5 μm.

The cam follower roller device comprises a body, a shaft mounted on the body, a roller mounted on the shaft and able to rotate, and a plain bearing interposed radially between the shaft and the roller. An outer surface and/or an inner surface of the plain bearing comprise a plurality of cavities. The ratio of the sum of the surfaces areas of the cavities to the total surface area of the outer surface, or of the inner surface, in which the cavities are formed is between 2% and 40%. The cavities have a depth between 0.5 μm and 5 μm.

A bearing housing (1) of an exhaust-gas turbocharger, having a compressor-side housing flange (2), a central housing section (3) which is integrally connected to the housing flange (2) and in which a first partial section (4) of an oil chamber (5) is arranged; and a turbine-side housing section (6) which has a turbine-side housing flange (7) and in which a second partial section (8) of the oil chamber (5) is formed. The central housing section (3) and the turbine-side housing section (6) are formed in one piece. A bearing housing (9) which forms a separate component is inserted into the central housing section (3) and into the turbine-side housing section (6), with these delimiting the oil chamber (5).

A turbocharger and a method of manufacturing a floating bush with which noise can be reduced, and the rotation speed can be increased. In a turbocharger in which a rotating shaft having a circular cross-section and connecting a turbine rotor and a compressor rotor is supported in a freely rotatable manner, at two axially separated positions via floating bushes, by an inner circumferential surface disposed so as to surround the rotating shaft in a bearing housing, an inner circumferential surface of each of the floating bushes has a non-circular shape in which the curvature of the cross-sectional shape varies in the circumferential direction.