ROTATING MACHINE WITH SHAFT SEALING ARRANGEMENT

• US 20120027569A1
• Filed: 04/01/2010
• Published: 02/02/2012
• Est. Priority Date: 04/02/2009
• Status: Active Grant

• Current Assignee: Cummins Turbo Technologies Limited (Cummins Incorporated)
• Original Assignee: Cummins Turbo Technologies Limited (Cummins Incorporated)
• Inventors: Purdey, Matthew J
• Granted Patent: US 9,194,256 B2
• Time in Patent Office: Days
• US Class Current: 415/1
• CPC Class Codes: F01D 11/00 Preventing or minimising internal leakage of working-fluid, e.g. between stages sealings in general F16J ; sealing arrangements for transition ducts of combustor cans F01D9/023
• CPC Class Codes: F01D 25/186 for sliding contact bearing
• CPC Class Codes: F02C 6/12 Turbochargers, i.e. plants for augmenting mechanical power output of internal-combustion piston engines by increase of charge pressure
• CPC Class Codes: F05D 2220/40 in turbochargers
• CPC Class Codes: F05D 2240/126 Baffles or ribs
• CPC Class Codes: F05D 2240/70 Slinger plates or washers
• CPC Class Codes: F05D 2250/324 divergent
• CPC Class Codes: F05D 2260/6022 of leakage having past a seal seals F05D2240/57; glands F05D2240/63

Abstract

A rotating machine comprising such as an axial power turbine or a turbocharger has a housing with a bearing cavity and a chamber separated by a first wall. A shaft is rotatable about an axis in the bearing cavity, extends through an opening in the first wall and is mounted for rotation on a bearing assembly provided in the bearing cavity. An oil sealing arrangement including an oil diffuser device is arranged on the shaft for displacing oil away from the shaft as it rotates. This restricts the flow of oil to the opening. The oil diffuser device defines a diffuser passage between the bearing assembly and the first wall, the passage extending outwardly of the axis.

Claims

1. A rotating machine comprising:

a housing defining a bearing cavity and a chamber separated by a first wall;

a shaft rotatable about an axis in the bearing cavity and extending through an opening in the first wall, the shaft being mounted for rotation on a bearing assembly provided in the bearing cavity;

an oil sealing arrangement for displacing oil away from the shaft as it rotates thereby restricting the flow of oil to the opening;

the oil sealing arrangement comprising an oil diffuser device defining an oil passage disposed between opposed surfaces of the bearing assembly and the first wall, the passage being configured for guiding and diffusing oil flow, the passage extending outwardly of the axis and having a radially inner first portion that extends in a first direction with a dominant radial component and a second portion outboard of the radially inner portion and extending in a second direction with a greater axial component than the first direction.

2. A rotating machine according to claim 1, wherein the passage has an outlet end distal from the shaft that extends in a direction away from the first wall.

3. A rotating machine according to claim 2, wherein the first portion of the diffuser passage has an inlet end that extends in a substantially radial direction.

4. A rotating machine according to claim 1, wherein the oil diffuser device comprises a fixed member that is designed not to rotate with the shaft and defines a first surface, and a rotatable member for rotation with the shaft and defines a second surface, the first and second surfaces facing each other and defining the diffuser passage between them.

5. A rotating machine according to claim 4, wherein the first surface has a first portion that extends in the first direction and a second portion that extends in the second direction, and the second surface has a first portion that extends in the first direction and a second portion that extends in the second direction.

6. A rotating machine according to claim 4, wherein the axial distance between the first and second surfaces increases with radial distance from the shaft.

7. A rotating machine according to claim 4, wherein the fixed member is defined by the housing.

8. A rotating machine according to claim 4, wherein the rotatable member of the diffuser device is substantially disc-shaped with a bore in which the shaft is received.

9. A rotating machine according to claim 8, wherein an outer periphery of the second surface of the rotatable member is curved in a direction away from the first wall.

10. A rotating machine according to claim 9, wherein the rotatable member is disposed in the bearing cavity such that there is a small annular clearance between its outer periphery and a neighbouring wall of the housing.

11. A rotating machine according to claim 1, wherein the oil sealing arrangement further comprises a labyrinth member disposed around the shaft for defining at least one oil collection chamber between the oil diffuser device and the first wall.

12. A rotating machine according to claim 11, wherein the at least one oil collection chamber is defined between the labyrinth member and a wall portion of the bearing cavity and is arranged to collect oil that passes through said small annular clearance.

13. A rotating machine according to claim 11, wherein the labyrinth member has at least one surface that is inclined with respect to the shaft axis for directing collected oil away from the shaft towards a drain.

14. A rotating machine according to claim 11, wherein there is provided a plurality of oil collection chambers arrange to receiving oil in sequence.

15. A rotating machine according to claim 1, wherein the sealing assembly further comprises at least one seal ring disposed around the shaft within the opening to seal the shaft with respect to the first wall.

16. A rotating machine according to claim 1 and in the form of a turbomachine.

17. A rotating machine according to claim 16, wherein the turbomachine is a turbocharger including a turbine or compressor housing defining the chamber, and a bearing housing defining said bearing cavity.

18. A rotating machine according to claim 16, wherein the turbomachine is a power turbine including a turbine housing defining the chamber, and a bearing housing defining said bearing cavity.

19. A rotating machine according to claim 1, wherein the passage is sized so as to ensure that when the oil emerges from the outlet the flow has decelerated such that the gravitational and surface tension forces dominate and cause the oil to pour from the outlet of the passage.

20. A rotating machine comprising:

a housing defining a bearing cavity and a chamber separated by a first wall;

a shaft rotatable in the bearing cavity about an axis and extending through an opening in the first wall, the shaft being mounted for rotation on a bearing assembly provided in the bearing cavity;

an oil sealing arrangement for displacing oil away from the shaft as it rotates thereby restricting the flow of oil to the opening;

the oil sealing arrangement comprising an oil diffuser device defining a substantially annular oil passage for guiding and diffusing the flow of oil towards an outlet, the oil passage being disposed between the bearing assembly and the first wall, the passage extending outwardly of the axis and being defined between first and second surfaces spaced apart such that, as the shaft rotates, oil flows along the passage as a body in contact with the first and second surfaces and decelerates such that gravitational and surface tension forces dominate and cause the oil to pour from the outlet of the passage.

21. A method of reducing oil leakage in a rotating machine comprising a housing defining a bearing cavity in which a shaft is arranged for rotation and a chamber separated by a first wall;

the method comprising using an oil diffuser around said shaft to direct a body of oil along a diffuser passage away from the shaft as it rotates and away from said chamber, the oil diffuser serving to reduce the flow velocity of the oil as it flows along the passage such that gravitational and surface tension forces dominate and the oil pours from an outlet of the passage.