Turbomachine disc cover mounting arrangement

Patent metadata

Field	Value
Publication number	US-10975707-B2
Application number	US-201816225343-A
Country	US
Kind code	B2
Filing date	Dec 19, 2018
Priority date	Dec 19, 2018
Publication date	Apr 13, 2021
Grant date	Apr 13, 2021

Abstract

A gas turbine engine rotary assembly comprises a disc mounted for rotation about an axis and having a first bayonet feature, a cover mounted to the disc; and a retaining ring having a second bayonet feature engaged with the first bayonet feature of the disc.

First claim

The invention claimed is:

1. A rotary assembly for a gas turbine engine, the rotary assembly comprising:
a disc mounted for rotation about an axis and having a first bayonet feature;
a cover mounted to the disc; and
a retaining ring having a second bayonet feature engaged axially behind the first bayonet feature of the disc, the cover axially biasing the second bayonet feature of the retaining ring in axial engagement with the first bayonet feature of the disc.

2. The rotary assembly defined in claim 1 , wherein the first and second bayonet features are provided with anti-rotation features to lock the retaining ring against rotation relative to the turbine disc.

3. The rotary assembly as defined in claim 1 , wherein the first bayonet feature includes a plurality of circumferentially spaced-apart disc lugs, the second bayonet feature includes a plurality of circumferentially spaced-apart ring lugs, and wherein the retaining ring is rotatable between a first angular orientation wherein the plurality of circumferentially spaced-apart ring lugs are angularly offset with respect to the plurality of circumferentially spaced-apart disc lugs, thereby allowing the retaining ring to be installed on the disc axially behind the plurality of circumferentially spaced-apart disc lugs, and a second in use angular orientation in which the plurality of circumferentially spaced-apart ring lugs are angularly aligned with the plurality of circumferentially spaced-apart disc lugs to prevent the retaining ring to move axially away from the disc.

4. The rotary assembly as defined in claim 3 , wherein the plurality of circumferentially spaced-apart disc lugs project radially outwardly from an axially extending stub shaft portion of the disc, and wherein the plurality of circumferentially spaced-apart ring lugs project radially inwardly from an inner dimeter of the retaining ring.

5. The rotary assembly as defined in claim 3 , wherein at least one of the plurality of circumferentially spaced-apart ring lugs or at least one of the plurality of circumferentially spaced-apart disc lugs has an anti-rotation recess formed in an axially facing surface thereof for receiving a corresponding one of the plurality of circumferentially spaced-apart disc lugs or a corresponding one of the plurality of circumferentially spaced-apart ring lugs in a circumferential captive manner to lock the retaining ring in rotation relative to the disc.

6. The rotary assembly as defined in claim 5 , wherein the anti-rotation recess is provided in the form of an undercut machined in the axially facing surface of the at least one of the plurality of circumferentially spaced-apart ring lugs or the at least one of the plurality of circumferentially spaced-apart disc lugs, the undercut being circumferentially bounded by end walls providing arresting surfaces for the corresponding one of the plurality of circumferentially spaced-apart disc lugs or the corresponding one of the plurality of circumferentially spaced-apart ring lugs.

7. A mounting arrangement for retaining a cover on a disc of a turbomachine rotor, the mounting arrangement comprising: a first bayonet feature provided on a stub shaft projecting axially from one face of the disc, a retaining ring engageable over the stub shaft and configured to retain an inner diameter portion of the cover on the disc, the retaining ring having a second bayonet feature axially engageable behind the first bayonet feature of the disc, the second bayonet feature being axially biased against the first bayonet feature by the cover as a result of an interference fit (F) at an outer rim interface between the disc and the cover.

8. The mounting arrangement as defined in claim 7 , wherein the first bayonet feature comprises a plurality of circumferentially spaced-apart disc lugs projecting radially outwardly from the inner diameter portion of the disc, and wherein the second bayonet feature comprises a plurality of circumferentially spaced-apart ring lugs projecting radially inwardly from an inner diameter of the retaining ring, the plurality of circumferentially spaced-apart ring lugs being axially insertable between the plurality of circumferentially spaced-apart disc lugs, the retaining ring being rotatable in a circumferential direction to angularly align the plurality of circumferentially spaced-apart ring lugs behind the plurality of circumferentially spaced-apart disc lugs.

9. The mounting arrangement defined in claim 8 , wherein the plurality of circumferentially spaced-apart ring lugs and the plurality of circumferentially spaced-apart disc lugs have complementary male-female interfacing surfaces including circumferential arresting surfaces to prevent rotation of the retaining ring in a circumferential direction relative to the disc.

10. The mounting arrangement defined in claim 9 , wherein the plurality of circumferentially spaced-apart ring lugs have a ring interface side opposite to a cover interface side, and wherein the plurality of circumferentially spaced-apart ring lugs incorporate undercuts on the ring interface side to accommodate the plurality of circumferentially spaced-apart ring lugs.

11. The mounting arrangement defined in claim 10 , wherein the undercuts are circumferentially bordered by circumferentially opposed end walls providing arresting surfaces for the plurality of circumferentially spaced-apart disc lugs in the circumferential direction.

12. The mounting arrangement defined in claim 8 , wherein the retaining ring has a cover interface side, and wherein the retaining ring is provided with a positioning aid on a side thereof opposite to the cover interface side.

13. The mounting arrangement defined in claim 12 , wherein the positioning aid includes assembly lugs projecting axially from the retaining ring in a direction away from the cover.

14. The mounting arrangement defined in claim 7 , wherein the first bayonet feature includes a plurality of circumferentially spaced-apart disc lugs, the second bayonet feature includes a plurality of circumferentially spaced-apart ring lugs, and wherein the retaining ring is rotatable between a first angular orientation wherein the plurality of circumferentially spaced-apart ring lugs are angularly offset with respect to the plurality of circumferentially spaced-apart disc lugs, thereby allowing the retaining ring to be fitted on the stub shaft of the disc axially behind the plurality of circumferentially spaced-apart disc lugs, and a second in use angular orientation in which the plurality of circumferentially spaced-apart ring lugs are angularly aligned with the plurality of circumferentially spaced-apart disc lugs to prevent the retaining ring to move axially away from the disc.

15. A method of assembling a cover to a turbomachine disc mounted for rotation about an axis, the method comprising: positioning the cover over one face of the turbomachine disc, and then axially engaging a bayonet feature of a retaining ring behind a corresponding bayonet feature of the turbomachine disc, wherein axially engaging comprises pushing the retaining ring axially against the cover towards the face of the turbomachine disc so as to elastically deform the cover beyond a running position thereof and then allowing the cover to spring back to its running position in a direction away from the face of the turbomachine disc, the cover being axially trapped at an inner diameter portion thereof between the disc and the retaining ring.

16. The method defined in claim 15 , wherein the bayonet feature of the retaining ring includes a plurality of circumferentially spaced-apart ring lugs, the correspondi

Assignees

• Pratt & Whitney Canada

Inventors

• Paradis Vincent
• Lefebvre Guy
• Pietrobon John

Classifications

• F05D2240/80

  Platforms for stationary or moving blades · CPC title

• F01D5/3015 Primary

  with side plates · CPC title

• F05D2240/55

  Seals · CPC title

• F01D11/006

  Sealing the gap between rotor blades or blades and rotor · CPC title

• F05D2260/33

  with a bayonet coupling · CPC title