On an inner circumferential surface (25a) of a housing (25) opposed to an outer circumferential surface (37a, 37b) of an outer ring, toward a front side in a rotation direction (B) of a rotation shaft (21), a first groove (41H, 41I) is formed as a groove portion for guiding an oil (39) in a direction toward a first oil supply hole (41D, 41E).

A turbine comprises a turbine wheel for rotation within a turbine housing, the turbine housing including at least one volute arranged to deliver a fluid to the turbine wheel via the turbine nozzle. A method for determining a width of a turbine nozzle for the turbine, comprises selecting from a relationship between a turbine stage efficiency and an effective nozzle area, at least one target effective nozzle area. As used here, the effective nozzle area is dependent on both the width of the turbine nozzle and a whirl angle induced by the at least one volute. The method further comprises determining, in dependence on the whirl angle, the width of the turbine nozzle as a width that will achieve the at least one target effective nozzle area.

A bearing arrangement for a turbomachine includes first and second roller element bearings. The first bearing and the second bearing are disposed on opposite axial ends of an intermediate sleeve of the rotating group. The first bearing has a first inner race with a first inner radial surface and a first outer radial surface. The first inner radial surface has a first interference fit with a shaft of the rotating group. The first outer radial surface has a second interference fit with the intermediate sleeve. The second bearing has a second inner race with a second inner radial surface and a second outer radial surface. The second inner race receives the shaft with a clearance fit. The second outer radial surface has a third interference fit with the intermediate sleeve. The second inner race is coaxially aligned with the first inner race and the shaft via coaxial alignment of the intermediate sleeve and the first inner race.

A bearing assembly for supporting rotation of a shaft in a turbocharger includes an inner race extending along an axis. The inner race is configured to be coupled to the shaft. The bearing assembly also includes an outer race spaced radially from the inner race and a cage disposed radially between the inner race and the outer race. The bearing assembly further includes a rolling element disposed radially between the outer race and the inner race. The rolling element is disposed within the cage for supporting rotation of the shaft. The outer race defines a lubricant passageway configured to direct lubricant toward the cage.

The invention relates to a bearing unit for a turbocharger rotor. The bearing unit comprises a bearing housing and a bearing bush which is arranged in a central bore for radially mounting a turbocharger rotor in the bearing housing. In the region of a first axial end, the bearing bush has a radially outwardly extending projection. The projection is designed to interact with the bearing housing as an anti-rotation safeguard for the bearing bush.

A thrust bearing device is provided with: a rotational shaft; a collar member fitted to the rotational shaft and having a first thrust surface; and a thrust member having an insertion hole into which the rotational shaft is inserted and a second thrust surface which is disposed around the insertion hole and faces the first thrust surface of the collar member. The first thrust surface is configured to be inclined with respect to a plane perpendicular to an axis of the rotational shaft so that a distance between the first thrust surface and the second thrust surface periodically increases and decreases with rotation of the rotational shaft.

Various methods and systems are provided for a radial turbocharger. In one example, the turbocharger comprises a turbine case housing a turbine wheel and a compressor case housing a compressor wheel, the turbine case including a vaneless turbine nozzle integrated into the turbine case, a bearing case surrounding a shaft connecting the turbine wheel to the compressor wheel and arranged between the turbine case and compressor case, a plurality of long bolts arranged around a circumference of the turbine case, and a plurality of slots arranged around a circumference of the turbine case, a slot length of each slot extending in a radial direction and adapted to receive a dowel pin having a diameter smaller than the slot length, where each dowel pin, via a corresponding slot, couples the bearing case to the turbine case.

A turbocharger includes a shaft, a compressor wheel, a turbine wheel, and a bearing assembly including an inner race, a first outer race spaced from the inner race, a second outer race spaced from the inner race, a first rolling element disposed between the first outer race and the inner race, and a second rolling element disposed between the second outer race and the inner race. The bearing assembly includes a first biasing member configured to bias the first outer race toward the second outer race and against the first rolling element, and preload the first rolling element with a preloading force, and a second biasing member configured to bias the second outer race toward the first outer race and against the second rolling element, and preload the second rolling element with a second preloading force. The first preloading force is different than the second preloading force.

A semi-floating bearing (multilobe bearing) including: an annular main body through which a shaft is inserted; and a radial bearing surface formed on an inner peripheral surface of the main body, the radial bearing surface including a plurality of arc surfaces having different curvature centers and disposed adjacent to each other in a circumferential direction of the main body, and a minimum distance Ra between a central axis of the shaft and the arc surface, a curvature radius Rb of the arc surface, and a radius Rs of the shaft satisfying relationships expressed by the following Formulas (1) and (2). Ra/Rs≥1.001 . . . (1), (Rb−Ra)/0.9≤(Rb−Rs)≤(Rb−Ra)/0.6 . . . (2) provided that Ra is the minimum distance between the central axis of the shaft and the arc surface, Rb is the curvature radius of the arc surface, and Rs is the radius of the shaft.

A semi-floating bearing (bearing) including: a main body, which has an annular shape, extends in a direction intersecting with a vertical direction, and has a shaft inserted through the main body; a radial bearing surface formed on an inner peripheral surface of the main body; and a plurality of oil supply grooves, which extend in an axial direction of the main body, are formed in the radial bearing surface at positions excluding a lowermost portion of the radial bearing surface in the vertical direction at intervals in a circumferential direction, and are arranged so as to be line-symmetric with each other with respect to a vertical axis in a cross section orthogonal to the axial direction of the radial bearing surface such that the interval between the oil supply grooves in the circumferential direction is the largest on a vertically lower side.