Abstract: A method of loading a rotating assembly of a turbocharger includes positioning a lock collar on an end portion of a turbocharger shaft that extends through a through bore of a compressor wheel; applying a pulling force to the end portion of the turbocharger shaft to achieve a desired amount of loading; welding the lock collar to form a welded lock collar fixed to the end portion of the turbocharger shaft; and releasing the pulling force where the welded lock collar maintains the desired amount of loading.

Abstract: A turbocharger system can include a housing that includes a through bore, a plurality of lubricant bores, a plurality of lubricant bore to through bore openings and a recessed compressor-side surface that defines in part a passage that fluidly couples at least two of the lubricant bores; a rolling element bearing unit disposed at least in part in the through bore of the housing; and, a plate that covers at least a portion of the recessed compressor-side surface of the housing.

Abstract: A compressor wheel assembly of a turbocharger can include a compressor wheel that includes a through bore that extends from a base portion to a nose portion of the compressor wheel; a turbocharger shaft disposed in the through bore of the compressor wheel where the turbocharger shaft includes an end portion that extends axially away from the nose portion of the compressor wheel; and a swaged collar fixed to the end portion of the turbocharger shaft.

Abstract: An assembly can include a turbocharger center housing that includes a through bore that extends between a compressor end and a turbine end of the turbocharger center housing where the through bore includes a sleeve mating surface; and a sleeve positioned at least in part in the through bore of the turbocharger center housing where the sleeve includes an outer mating surface, an inner compressor side bearing lubricant film formation surface disposed at a first radius, an inner turbine side bearing lubricant film formation surface disposed at a second radius, and a surface between the inner compressor side bearing lubricant film formation surface and the inner turbine side bearing lubricant film formation surface that includes a third radius that is less than the first radius and less than the second radius and where outer mating surface of the sleeve contacts the sleeve mating surface of the turbocharger center.

Abstract: An assembly can include a turbocharger center housing that includes a through bore and a counterbore positioned between a compressor end and a turbine end of the through bore where the through bore includes a sleeve mating surface positioned between the compressor end and the counterbore and a turbine side bearing lubricant film formation surface positioned between the counterbore and the turbine end; and a sleeve positioned at least in part in the through bore of the turbocharger center housing between the compressor end and the counterbore where the sleeve includes a locating flange and an axial extension that extends from the locating flange where the axial extension includes an outer mating surface, an inner compressor side bearing lubricant film formation surface, a compressor side axially facing spacer surface and a turbine side axially facing spacer surface.

Abstract: A method of loading a rotating assembly of a turbocharger includes positioning a lock collar on an end portion of a turbocharger shaft that extends through a through bore of a compressor wheel; applying a pulling force to the end portion of the turbocharger shaft to achieve a desired amount of loading; welding the lock collar to form a welded lock collar fixed to the end portion of the turbocharger shaft; and releasing the pulling force where the welded lock collar maintains the desired amount of loading.

Abstract: A turbocharger system can include a housing that includes a through bore, a plurality of lubricant bores, a plurality of lubricant bore to through bore openings and a recessed compressor-side surface that defines in part a passage that fluidly couples at least two of the lubricant bores; a rolling element bearing unit disposed at least in part in the through bore of the housing; and, a plate that covers at least a portion of the recessed compressor-side surface of the housing.

Abstract: A turbocharger assembly can include a housing with a through bore and an axial face disposed in the through bore; a locating plate with a keyed opening attached to the housing; and a journal bearing disposed in the through bore where the journal bearing includes a keyed compressor end and an enlarged outer portion defined between two axial faces by an outer diameter and an axial length where the axial face disposed in the through bore of the housing, the locating plate, and the two axial faces of the journal bearing axially locate the journal bearing in the through bore and where the keyed opening of the locating plate and the keyed compressor end of the journal bearing azimuthally locate the journal bearing in the through bore. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.

Abstract: A compressor wheel assembly of a turbocharger can include a compressor wheel that includes a through bore that extends from a base portion to a nose portion of the compressor wheel; a turbocharger shaft disposed in the through bore of the compressor wheel where the turbocharger shaft includes an end portion that extends axially away from the nose portion of the compressor wheel; and a swaged collar fixed to the end portion of the turbocharger shaft.

Abstract: A turbocharger bearing assembly can include a spacer that includes an axial through bore, a compressor side surface and a turbine side surface; a compressor side rolling element bearing that includes an outer race surface that faces the compressor side surface of the spacer; a turbine side rolling element bearing that includes an outer race surface that faces the turbine side surface of the spacer; and a spring seated between a first end cap disposed at least in part in the axial through bore of the spacer and a second end cap disposed at least in part in the axial through bore of the spacer where the spring biases an axially facing surface of the first end cap against the outer race surface of the compressor side rolling element bearing and where the spring biases an axially facing surface of the second end cap against the outer race surface of the turbine side rolling element bearing.

Abstract: A turbocharger bearing assembly can include a spacer that includes an axial through bore, a compressor side surface and a turbine side surface; a compressor side rolling element bearing that includes an outer race surface that faces the compressor side surface of the spacer; a turbine side rolling element bearing that includes an outer race surface that faces the turbine side surface of the spacer; and a spring seated between a first end cap disposed at least in part in the axial through bore of the spacer and a second end cap disposed at least in part in the axial through bore of the spacer where the spring biases an axially facing surface of the first end cap against the outer race surface of the compressor side rolling element bearing and where the spring biases an axially facing surface of the second end cap against the outer race surface of the turbine side rolling element bearing.

Abstract: An assembly can include a turbocharger center housing that includes a through bore and a counterbore positioned between a compressor end and a turbine end of the through bore where the through bore includes a sleeve mating surface positioned between the compressor end and the counterbore and a turbine side bearing lubricant film formation surface positioned between the counterbore and the turbine end; and a sleeve positioned at least in part in the through bore of the turbocharger center housing between the compressor end and the counterbore where the sleeve includes a locating flange and an axial extension that extends from the locating flange where the axial extension includes an outer mating surface, an inner compressor side bearing lubricant film formation surface, a compressor side axially facing spacer surface and a turbine side axially facing spacer surface.

Abstract: An assembly can include a turbocharger center housing that includes a through bore that extends between a compressor end and a turbine end of the turbocharger center housing where the through bore includes a sleeve mating surface; and a sleeve positioned at least in part in the through bore of the turbocharger center housing where the sleeve includes an outer mating surface, an inner compressor side bearing lubricant film formation surface disposed at a first radius, an inner turbine side bearing lubricant film formation surface disposed at a second radius, and a surface between the inner compressor side bearing lubricant film formation surface and the inner turbine side bearing lubricant film formation surface that includes a third radius that is less than the first radius and less than the second radius and where outer mating surface of the sleeve contacts the sleeve mating surface of the turbocharger center.

Abstract: A turbocharger assembly can include a housing with a through bore and an axial face disposed in the through bore; a locating plate with a keyed opening attached to the housing; and a journal bearing disposed in the through bore where the journal bearing includes a keyed compressor end and an enlarged outer portion defined between two axial faces by an outer diameter and an axial length where the axial face disposed in the through bore of the housing, the locating plate, and the two axial faces of the journal bearing axially locate the journal bearing in the through bore and where the keyed opening of the locating plate and the keyed compressor end of the journal bearing azimuthally locate the journal bearing in the through bore. Various other examples of devices, assemblies, systems, methods, etc., are also disclosed.