ANTI-ROTATION FEATURE FOR AIR TURBINE STARTER

• US 20120020784A1
• Filed: 07/23/2010
• Published: 01/26/2012
• Est. Priority Date: 07/23/2010
• Status: Active Grant

• Current Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Original Assignee: Hamilton Sundstrand Corporation (Rtx Corporation)
• Inventors: Makulec, Jeffrey M., Trommer, William C.
• Granted Patent: US 8,475,116 B2
• Time in Patent Office: Days
• US Class Current: 415/229
• CPC Class Codes: F01D 25/16 Arrangement of bearings; Supporting or mounting bearings in casings bearings per se F16C
• CPC Class Codes: F05D 2270/116 by preventing reverse rotation
• CPC Class Codes: Y10T 29/53 Means to assemble or disassemble

Abstract

A turbine balance assembly has a turbine rotor and shaft. Bearings are positioned radially outwardly of the shaft. A bearing sleeve is positioned radially outwardly of the bearings, and supports the bearings. The bearing sleeve extends along an axial length defined by a rotational axis of the shaft, and has a turbine rotor end adjacent to the turbine rotor, and a remote end. A radially outwardly extending flange on the bearing sleeve extends radially outwardly of a support portion of the bearing sleeve at the turbine rotor end. The flange has a nominal outer diameter, and includes a slot for receiving an anti-rotation tab from a gear cage over a first circumferential extent. A bearing sleeve incorporates the anti-rotation feature, and a gear cage incorporates its portion of the anti-rotation feature. An air turbine starter, and a method of installing components of a turbine balance assembly are also disclosed.

Claims

1. A turbine balance assembly comprising:

a turbine rotor connected to drive a turbine shaft;

bearings positioned radially outwardly of said turbine shaft;

a bearing sleeve positioned radially outwardly of said bearings, and supporting said bearings, said bearing sleeve extending along an axial length defined by a rotational axis of said shaft, and said bearing sleeve having a turbine rotor end adjacent to said turbine rotor, and a remote end;

a radially outwardly extending flange on said bearing sleeve extending radially outwardly of a support portion of said bearing sleeve and at said turbine rotor end, and said flange having a nominal outer radius, and including a slot for receiving an anti-rotation lock over a limited circumferential extent.

2. The turbine balance assembly as set forth in claim 1, wherein said slot extends over an angle of between 4°

and 12°

to define said limited circumferential extent.

3. The turbine balance assembly as set forth in claim 1, wherein a ratio between a distance from a center line of said bearing sleeve to a tangent point for a flat surface on a radially inner end of said tab relative to said nominal radius of the flange is between 0.92 and 0.95.

4. The turbine balance assembly as set forth in claim 3, wherein said slot extends for a distance along said flat surface between two sides, and a ratio of the distance between said two sides to said nominal radius is between 0.09 and 0.22.

5. An air turbine starter comprising:

a turbine rotor connected to drive a turbine shaft;

bearings positioned radially outwardly of said turbine shaft;

a bearing sleeve positioned radially outwardly of said bearings, and supporting said bearings, said bearing sleeve extending along an axial length defined by a rotational axis of said shaft, and said bearing sleeve having a turbine rotor end adjacent to said turbine rotor, and a remote end;

a radially outwardly extending flange on said bearing sleeve extending radially outwardly of a support portion of said bearing sleeve and at said turbine rotor end, and said flange having a nominal outer diameter, and including a slot for receiving an anti-rotation lock over a limited circumferential extent; and

a gear cage including an anti-rotation tab extending into said slot to resist rotation of said bearing sleeve relative to said gear cage.

6. The air turbine starter as set forth in claim 5, wherein said slot extends over an angle of between 4°

and 12°

to define said limited circumferential extent.

7. The air turbine starter as set forth in claim 5, wherein a ratio between a distance from a center line of said bearing sleeve to a tangent point for a flat surface on a radially inner end of said slot relative to said nominal radius of the flange is between 0.92 and 0.95.

8. The air turbine starter as set forth in claim 7, wherein said slot extends for a distance along said flat surface between two sides, and a ratio of the distance between said two sides to said nominal radius is between 0.09 and 0.22.

9. The air turbine starter as set forth in claim 5, wherein said gear cage is formed of an outer aluminum member having an inner bore, and a steel liner force fit into said inner bore, said tab being part of said steel liner.

10. The air turbine starter as set forth in claim 9, wherein said tab and said outer aluminum member extend along the axial dimension closer to said rotor over a limited circumferential extent associated with said slot, and said steel liner and said gear cage having surfaces that are more removed from said turbine rotor at locations other than said limited circumferential extent.

11. The air turbine starter as set forth in claim 9, wherein said steel liner has the tab formed in an axially forward end spaced more toward said turbine rotor than a remote end, and there being an outer diameter of said steel liner, and a ratio of an inner diameter of said forward end to said outer diameter is between 0.92 and 0.98.

12. The air turbine starter as set forth in claim 11, wherein a ratio of said inner diameter of said forward end to an axial length of the entire steel liner is between 12.5 and 4.5.

13. A gear cage comprising:

an outer aluminum member having a cylindrical inner bore;

a steel liner force fit into said inner bore, a tab being formed as part of said steel liner, and said tab and said outer aluminum member extending along an axial dimension more forwardly than a nominal face of said liner and said outer aluminum member, and over a limited circumferential extent; and

wherein said steel liner has the tab formed in an axially forward end spaced more toward said turbine rotor than a remote end, and there being an outer diameter of said steel liner, and a ratio of an inner diameter of said forward end to said outer diameter is between 0.92 and 0.98.

14. The gear cage as set forth in claim 13, wherein a ratio of said inner diameter of said forward end to an axial length of the entire steel liner is between 12.5 and 4.5.

15. A bearing sleeve having a support portion extending along a central axis, and having a flange at a turbine end extending radially outwardly;

and

said flange having a nominal outer radius, and a slot for receiving an anti-rotation lock over a limited circumferential extent, said slot extending over an angle of between 4° and

12°

to define said limited circumferential extent.

16. The bearing sleeve as set forth in claim 15, wherein a ratio between a distance from a center line of said bearing sleeve to a tangent point for a flat surface on a radially inner end of said slot relative to said nominal radius of the flange is between 0.92 and 0.95.

17. The bearing sleeve as set forth in claim 16, wherein said slot extends for a distance along said flat surface between two sides, and a ratio of the distance between said two sides to said nominal radius is between 0.09 and 0.22.

18. A method of assembling an air turbine starter comprising the steps of:

inserting a turbine rotor and shaft, and bearings supporting said shaft into a bearing sleeve to form a turbine balance assembly, and said bearing sleeve having a slot to receive an anti-rotation structure at an end of said bearing sleeve positioned toward said turbine rotor; and

moving said turbine balance assembly into a gear cage, said gear cage having an anti-rotation tab and said tab being moved into said slot.

19. The method as set forth in claim 18, wherein said gear cage is formed of an outer member having an inner bore, and a liner force fit into said inner bore, with said liner providing the tab.

20. The method as set forth in claim 19, wherein said outer member and said liner initially have cylindrical forward surfaces, and said cylindrical forward surfaces of said outer aluminum member and said liner are machined away to leave said tab, and a portion of said cylindrical forward surfaces of said outer member over a limited circumferential extent prior to said turbine balance assembly being inserted within said gear cage.