Search

EP-4737684-A2 - SHAFT ASSEMBLY FOR A GAS TURBINE ENGINE

EP4737684A2EP 4737684 A2EP4737684 A2EP 4737684A2EP-4737684-A2

Abstract

A shaft assembly (42) for a gas turbine engine (20) including an outer shaft (46), an inner shaft (44), a lock nut (48), a locking shaft (50), and a washer (52). The outer shaft (46) includes a bore (56) extending between first and second ends. A portion (74, 78, 82) of the inner shaft (44) extends within the bore (56) of the outer shaft (46). The lock nut (48) is secured to the inner shaft (44) proximate a second axial end (74) of the inner shaft (44). The locking shaft (50) includes a body portion (100) extending between a coupling end (102) and a retaining end (104). The locking shaft (50) is disposed within the bore (56), with the coupling end (102) engageable with an end of the lock nut (48). A washer (52) is engageable with the retaining end (104) and the outer shaft second end. In the assembled state, the locking shaft (50) prevents rotation of the lock nut (48).

Inventors

  • BANVILLE, ROSE-ELIZABETH
  • QUINTIN, HUGO
  • HANNESTO, Jeffica
  • LABBE, MICHEL

Assignees

  • PRATT & WHITNEY CANADA CORP.

Dates

Publication Date
20260506
Application Date
20251103

Claims (15)

  1. A shaft assembly (42) for a gas turbine engine (20), comprising: an outer shaft (46) having a first end (63), a second end (64), an axial centerline (40, 62, 76) and a bore (56) extending between the first end (63) and the second end (64); an inner shaft (44) having a first axial end and a second axial end (74), at least a portion (74, 78, 82) of the inner shaft (44) extending within the outer shaft bore (56), the inner shaft (44) extending along the axial centerline (40, 62, 76); a lock nut (48) having a base (84) extending between a first nut end (94) and a second nut end (96), the lock nut (48) secured to the inner shaft (44) proximate the second axial end (74); a locking shaft (50) including a coupling end (102), a retaining end (104), and a body portion (100) extending between the coupling end (102) and the retaining end (104), the locking shaft (50) disposed within the outer shaft bore (56) and extending along the axial centerline (40, 62, 76), and the coupling end (102) engageable with the lock nut first nut end (94) or the second nut end (96); and a washer (52) including a washer inner circumferential surface (144) and a washer outer circumferential surface (146), the washer inner circumferential surface (144) engageable with the locking shaft retaining end (104) and the washer outer circumferential surface (146) engageable with the outer shaft (46) at the second end (64); wherein in an assembled state the locking shaft (50) prevents rotation of the lock nut (48).
  2. The shaft assembly (42) of claim 1, wherein the second end (64) includes an outer assembly surface (60) and a slot (72), the slot (72) extending from the outer assembly surface (60) to the bore (56); the washer outer circumferential surface (146) includes a radially-outward protruding tab (152); and in the assembled state the radially-outward protruding tab (152) engages the slot (72).
  3. The shaft assembly (42) of claim 1 or 2, wherein the retaining end (104) includes a second opening (122), an inner circumferential surface (124), an outer circumferential surface (126), and a gap (140), the gap (140) extending between the inner circumferential surface (124) and the outer circumferential surface (126); the washer inner circumferential surface (144) includes a radially-inward protruding tab (150); and in the assembled state the radially-inward protruding tab (150) engages the gap (140).
  4. The shaft assembly (42) of claim 1, 2 or 3, wherein the coupling end (102) includes an opening (106) forming a central chamber (114) extending axially towards the retaining end (104); and in the assembled state the inner shaft second axial end (74) is disposed within the central chamber (114).
  5. The shaft assembly (42) of any preceding claim, wherein the lock nut (48) includes a castellation (92) extending from the first nut end (94) or the second nut end (96), the castellation (92) protruding within the outer shaft bore (56); the coupling end (102) includes an outer shaft surface (108) and a lug (116), the lug (116) extending radially from the outer shaft surface (108) to an outer radial surface (118), the lug (116) extending axially from the coupling end (102) to a distal end (120); and in the assembled state the coupling end lug (116) is retained within the lock nut castellation (92).
  6. The shaft assembly (42) of any of claims 1 to 5, wherein the lock nut (48) includes a plurality of castellations (92) circumferentially disposed around the lock nut (48) and extending from the first nut end (94) or the second nut end (96), the plurality of castellations (92) extending within the outer shaft bore (56); the coupling end (102) includes an outer shaft surface (108) and a plurality of lugs (116) circumferentially disposed around the coupling end (102), each of the plurality of lugs (116) extending radially from the outer shaft surface (108) to an outer radial surface (118), each of the plurality of lugs (116) extending axially from the coupling end (102) to a distal end (120), and each of the plurality of lugs (116) angularly offset from another by a predetermined angle; and in the assembled state a first of the plurality of lugs (116) engage a first of the plurality of castellations (92), and a second of the plurality of lugs (116) engages a second of the plurality of castellations (92).
  7. The shaft assembly (42) of any preceding claim, further comprising a retaining ring (54) disposed within the outer shaft bore (56) aft of the washer (52), the retaining ring (54) including a ring outer circumferential surface (158) which engages a groove (70) disposed in an inner bore surface (58) of the outer shaft (46).
  8. The shaft assembly (42) of any preceding claim, wherein the inner shaft (44) comprises a low pressure turbine shaft (38), and/or the inner shaft (44) is in driving communication with a rotatable load (L).
  9. The shaft assembly (42) of any preceding claim, wherein the locking shaft retaining end (104) includes an outer circumferential surface (126) extending axially forward to a tapered region (130), the tapered region (130) extending axially towards the locking shaft body (100) such that the outer circumferential surface (126) tapers radially inward toward an outer shaft surface (108) of the locking shaft body (100).
  10. The shaft assembly (42) of claim 9, wherein the retaining end outer circumferential surface (126) includes at least one radial seal (128, 128A, 128B), and the at least one radial seal (128, 128A, 128B) engages an inner bore surface (58) of the outer shaft (46) in the assembled state.
  11. A locking shaft (50) for a gas turbine engine (20) having a rotating assembly (42), the locking shaft (50) comprising: a coupling end (102), a retaining end (104), and a body (100) extending axially between the coupling end (102) and the retaining end (104); the body (100) extending between the coupling end (102) and the retaining end (104), the body (100) including a central chamber (114), an inner shaft surface (110) and an outer shaft surface (108); the coupling end (102) including a lug (116) extending radially from the outer shaft surface (108) to an outer radial surface (118), the lug (116) extending axially from the coupling end (102) to a distal end (120); and the retaining end (104) includes a cavity (132), an inner circumferential surface (124), an outer circumferential surface (126), and a gap (140), the gap (140) extending between the inner circumferential surface (124) and the outer circumferential surface (126).
  12. The locking shaft (50) of claim 11, wherein the coupling end (102) includes a plurality of lugs (116) circumferentially disposed around the coupling end (102), each of the plurality of lugs (116) angularly offset from another by a predetermined angle, and/or wherein the retaining end (104) includes a plurality of gaps (140) circumferentially disposed around the retaining end (104).
  13. The locking shaft (50) of claim 11 or 12, wherein the locking shaft retaining end outer circumferential surface (126) extends axially forward to a tapered region (130), and the tapered region (130) extends axially towards the body (100) such that the outer circumferential surface (126) tapers radially inward toward the outer shaft surface (108) of the body (100).
  14. The locking shaft (50) of claim 11, 12 or 13, wherein the coupling end (102) includes an opening (106) in communication with the central chamber (114), the central chamber (114) extending axially from the opening (106) towards the retaining end (104), and/or wherein the coupling end (102) includes a first diameter and the retaining end (104) includes a second diameter, and the first diameter is less than the second diameter.
  15. A method of assembling a gas turbine engine component, comprising: providing a shaft assembly (42) including an outer shaft (46), an inner shaft (44), and a lock nut (48), the outer shaft (46) extending axially along a centerline (40, 62, 76) from a forward end (63) to an aft end (64), the inner shaft (44) extending along the centerline (40, 62, 76), and a portion (74, 78, 82) of the inner shaft (44) disposed within a bore (56) of the outer shaft (46); securing the lock nut (48) to a threaded section (78) of the inner shaft (44); inserting a locking shaft (50) within the bore (56) and engaging a first end (102) of the locking shaft (50) with an end of the lock nut (48); orienting a washer (52) to align a radially-inward protruding tab (150) with a second end (104) of the locking shaft (50), and align a radially-outward protruding tab (152) with the outer shaft aft end (64); and inserting the washer (52) within the shaft assembly (42) to engage the radially-inward protruding tab (150) with the second end (104) of the locking shaft (50) and the radially-outward protruding tab (152) with the aft end (64) of the outer shaft (46), wherein, optionally, the method further comprises selecting a classification of the washer (52).

Description

TECHNICAL FIELD This disclosure relates generally to gas turbine engines and particularly to a shaft assembly for such gas turbine engines. BACKGROUND INFORMATION Various shaft assemblies for gas turbine engines are known in the art, and mechanical locking systems are known in the art for securing shaft components using a locking mechanism, such as through interference engagement with associated bearings of a shaft component. While these known mechanical locking systems have various advantages, there is still room in the art for improvement. In particular, there is a need in the art for a mechanical locking system which can be conveniently and efficiently added to or removed from a gas turbine engine shaft assembly. SUMMARY According to an aspect of the present invention, a shaft assembly for a gas turbine engine is provided. The shaft assembly includes an outer shaft, an inner shaft, a lock nut, a locking shaft, and a washer. The outer shaft includes a first end, a second end, an axial centerline, and a bore extending between the first end and the second end. The inner shaft includes a first axial end and a second axial end. At least a portion of the inner shaft extends within the outer shaft bore. The inner shaft extends along the axial centerline. The lock nut includes a base extending between a first nut end and a second nut end. The lock nut is secured to the inner shaft proximate the second axial end. The washer includes a washer inner circumferential surface and a washer outer circumferential surface. The washer inner circumferential surface is engageable with the locking shaft retaining end and the washer outer circumferential surface is engageable with the outer shaft at the second end. In an assembled state, the locking shaft prevents rotation of the lock nut. In an embodiment of the above, the second end includes an outer assembly surface and a slot, the slot extending from the outer assembly surface to the bore. The washer outer circumferential surface may include a radially-outward protruding tab. In the assembled state, the radially-outward protruding tab engages the slot. In any of the aspects or embodiments described above, the retaining end includes a second opening, an inner circumferential surface, an outer circumferential surface, and a gap. The gap extends between the inner circumferential surface and the outer circumferential surface. The washer inner circumferential surface includes a radially-inward protruding tab. In the assembled state, the radially-inward protruding tab engages the gap. In any of the aspects or embodiments described above, the lock nut includes a castellation extending from the first nut end or the second nut end. The castellation protrudes within the outer bore shaft. The coupling end includes an outer shaft surface and a lug. The lug may extend radially from the outer shaft surface to an outer radial surface. The lug may extend axially from the coupling end to a distal end. In the assembled state the coupling end lug is retained within the lock nut castellation. In any of the aspects or embodiments described above, the coupling end includes an opening forming a central chamber extending axially towards the retaining end. In the assembled state, the inner shaft second axial end is disposed within the central chamber. In any of the aspects or embodiments described above, the lock nut includes a plurality of castellations circumferentially disposed around the lock nut and extending from the first nut end or the second nut end. The plurality of castellations may extend within the outer shaft bore. The coupling end may include an outer shaft surface and a plurality of lugs circumferentially disposed around the coupling end. Each of the plurality of lugs may extend radially from the outer shaft surface to an outer radial surface. Each of the plurality of lugs may extend axially from the coupling end to a distal end. Each of the plurality of lugs may be angularly offset from another by a predetermined angle. In the assembled state, a first of the plurality of lugs may engage a first of the plurality of castellations. A second of the plurality of lugs may engage a second of the plurality of castellations. In any of the aspects or embodiments described above, the shaft assembly includes a retaining ring disposed within the outer shaft bore aft of the washer. The retaining ring may include a ring outer circumferential surface which engages a groove disposed in an inner bore surface of the outer shaft. In any of the aspects or embodiments described above, the inner shaft may comprise a low pressure turbine shaft. In any of the aspects or embodiments described above, the locking shaft retaining end includes an outer circumferential surface extending axially forward to a tapered region, the tapered region extending axially towards the locking shaft body such that the outer circumferential surface tapers radially inward toward an outer shaft surface of the locking shaft body.