Multi-lobe semi-floating journal bearing
View Patent ↗An exemplary turbocharger assembly includes a housing with a through bore having a central axis extending between a compressor end and a turbine end of the housing and a bearing, configured for receipt by the through bore, where the bearing includes an inner journal configured to rotatably support a turbocharger shaft and where the inner journal includes a central axis, an axial length, a lubricant opening, an axially confined lubricant well, a lubricant ramp, and a lubricant channel that spans the axial length of the inner journal. Various other exemplary devices, systems, methods, etc., are also disclosed.
1. A turbocharger assembly comprising:
a housing that comprises a through bore having a central axis extending between a compressor end and a turbine end of the housing; and
a bearing, configured for receipt by the through bore, wherein the bearing comprises an inner journal configured to rotatably support a turbocharger shaft with an intended direction of rotation and wherein the inner journal comprises
a central axis,
an axial length,
a lubricant opening,
an axially confined lubricant well wherein the lubricant opening opens to the lubricant well,
a lubricant ramp that comprises an arc span, in the intended direction of rotation of the turbocharger shaft, from a first radial distance measured from the central axis to a second, lesser radial distance measured from the central axis, the axially confined lubricant well and the lubricant opening being disposed within the arc span of the lubricant ramp,
a lubricant channel that spans the axial length of the inner journal, and
a lubricant flow path defined by a radial depth, an axial width and an arc span, in a direction opposite to the intended direction of rotation of the turbocharger shaft, from the axially confined lubricant well to the lubricant channel.
2. The turbocharger assembly of claim 1 wherein the lubricant opening is disposed within the lubricant well.
3. The turbocharger assembly of claim 1 where the arc span of the lubricant ramp is defined by an axial point offset from the central axis of the inner journal.
4. The turbocharger assembly of claim 1 wherein the inner journal comprises two or more of the lubricant openings, two or more of the axially confined lubricant wells, two or more of the lubricant ramps, two or more of the lubricant channels, and two or more of the lubricant flow paths.
5. The turbocharger assembly of claim 1 wherein the bearing comprises two of the inner journals.
6. The turbocharger assembly of claim 1 comprising another lubricant channel wherein the inner journal further comprises a pad disposed between the lubricant ramp and the other lubricant channel.
7. The turbocharger assembly of claim 1 further comprising a turbocharger shaft configured for rotation in a direction from the lubricant opening to at least a portion of the lubricant ramp and to the lubricant channel.
8. The turbocharger assembly of claim 1 comprising two of the inner journals, the two inner journals comprising a compressor end inner journal and a turbine end inner journal and further comprising a center section disposed between the two inner journals.
9. A method of operating a turbocharger, the method comprising:
providing lubricant to a lubricant opening in a bearing disposed in a through bore of a center housing of the turbocharger;
rotating a turbocharger shaft, supported by the bearing, in a clockwise direction;
flowing the lubricant from the lubricant opening to an axially confined lubricant well disposed within an arc span of a lubricant ramp;
flowing the lubricant in a clockwise direction from the axially confined lubricant well along the lubricant ramp to a pad at an end of the lubricant ramp and to a lubricant channel that extends axially to an end of the bearing;
flowing the lubricant out of the end of bearing;
halting the rotating of the turbocharger shaft; and
flowing lubricant from the lubricant opening to the lubricant channel in a counter-clockwise direction in a lubricant flow path defined by a radial depth, an axial width and an arc span.
10. The method of claim 9 wherein the method comprises avoiding lubricant coking by flowing the lubricant at a rate sufficient to prevent temperatures or temperature-time profiles associated with coke formation.
11. The turbocharger assembly of claim 1 wherein the arc span of the lubricant ramp extends from the lubricant channel to a pad.
12. The turbocharger assembly of claim 11 wherein the lubricant ramp comprises the first radial distance at the lubricant channel and the second radial distance proximate to the pad.
13. The method of claim 9 wherein the lubricant ramp comprises another end that coincides with the lubricant channel.
14. The method of claim 9 wherein the lubricant ramp comprises a first radial distance measured from a central axis of the bearing at the lubricant channel and a second, lesser radial distance measured from the central axis of the bearing proximate to the pad.