Chocking and retaining device

Patent metadata

Field	Value
Publication number	US-10145250-B2
Application number	US-201615057407-A
Country	US
Kind code	B2
Filing date	Mar 1, 2016
Priority date	Mar 12, 2015
Publication date	Dec 4, 2018
Grant date	Dec 4, 2018

Abstract

A device for chocking and retaining a dovetail root of a blade of a gas turbine engine in a corresponding axially-extending slot in the rim of a disc includes a retention body having a key portion receivable in a keyway formed in the base of the slot, and a mating portion for mating with a complementary mating portion of the root to prevent relative axial movement between the retention body and the root. The retention body has a lowered position in which the key portion is received sufficiently deeply in the keyway to allow the root to be positioned in the slot without interference from the retention body and also has a raised position in which, after the root is positioned in the slot, a part of the key portion is still received in the keyway while the mating portion mates with the complementary mating portion of the root.

First claim

The invention claimed is:

1. A device for chocking and retaining a dovetail root of a blade of a gas turbine engine in a corresponding axially-extending slot in the rim of a disc, the device including:
a retention body having:
a key portion receivable in a keyway formed in the base of the slot, the key portion comprising one or more legs and the keyway comprising one or more slots for respectively receiving the legs,
a mating portion for mating with a complementary mating portion of the root to prevent relative axial movement between the retention body and the root, and
the retention body having a lowered position in which the key portion is received sufficiently deeply in the keyway to allow the root to be positioned in the slot without interference from the retention body, and a raised position in which, after the root is positioned in the slot, a part of the key portion is still received in the keyway while the mating portion mates with the complementary mating portion of the root;

a slider which is axially insertable in the slot;
wherein the slider and the retention body are configured so that, on axial insertion of the slider in the slot after the root is positioned in the slot, the slider moves the retention body from its lowered position to its raised position, whereby the retention body urges the blade radially outwardly thereby mating flanks of the root to flanks of the slot, while the part of the key portion still received in the keyway retains the root axially in the slot.

2. A device according to claim 1 , wherein the retention body has a chamfered lead-in portion against which the slider slides on axial insertion of the slider in the slot to move the retention body from its lowered position to its raised position.

3. A device according to claim 1 , wherein the slider has a chamfered or rounded leading edge.

4. A device according to claim 1 , wherein the mating portion forms an arc-shaped surface of the retention body and the complementary mating portion forms a correspondingly arc-shaped surface of the root, the normal to the plane of the arc of each arc-shaped surface being substantially perpendicular to the engine axis, whereby the arc-shaped surfaces mate to prevent relative axial movement between the retention body and the root.

5. A device according to claim 4 , wherein the normal to the plane of each arc is substantially perpendicular to the radial direction.

6. A device according to claim 4 , wherein the arc-shaped surface of the retention body is a convex surface.

7. A device according to claim 4 , wherein the arc-shaped surface of the retention body is a concave surface.

8. A device according to claim 1 , wherein of the mating portion of the retention body has a relatively compliant outer layer for enhanced contact of the retention body with the root.

9. A device according to claim 1 , wherein the slider has one or more chock springs which are arranged to act, in use, on the root to also urge the blade radially outwardly.

10. A device according to claim 1 , wherein the slider has a stop at an end thereof which, in use, abuts a face of the disc or the root when the slider is fully inserted in the slot to prevent over-insertion of the slider.

11. A device according to claim 1 including a plurality of the retention bodies, each movable by the slider from its lowered position to its raised position.

12. A rotor assembly of a gas turbine engine, the assembly having:
a disc;
a circumferential row of blades, each blade having a dovetail root which is retained in a corresponding axially-extending slot in the rim of the disc; and
a plurality of devices according to claim 1 for chocking and retaining the dovetail roots of the blades in the slots;
wherein each slot has a keyway formed in the base thereof, the key portion of the retention body of each device is received in a respective one of the keyways, and the slider of each device is inserted in a respective one of the slots to move its retention body to the raised position.

13. A gas turbine engine having the rotor assembly of claim 12 .

14. A device for chocking and retaining a dovetail root of a blade of a gas turbine engine in a corresponding axially-extending slot in the rim of a disc, the device including:
a retention body having:
a key portion receivable in a keyway formed in the base of the slot,
a mating portion for mating with a complementary mating portion of the root to prevent relative axial movement between the retention body and the root, the mating portion forming an arc-shaped surface of the retention body and the complementary mating portion forming a correspondingly arc-shaped surface of the root, the normal to the plane of the arc of each arc-shaped surface being substantially perpendicular to the engine axis, whereby the arc-shaped surfaces mate to prevent relative axial movement between the retention body and the root, and
the retention body having a lowered position in which the key portion is received sufficiently deeply in the keyway to allow the root to be positioned in the slot without interference from the retention body, and a raised position in which, after the root is positioned in the slot, a part of the key portion is still received in the keyway while the mating portion mates with the complementary mating portion of the root;

a slider which is axially insertable in the slot;
wherein the slider and the retention body are configured so that, on axial insertion of the slider in the slot after the root is positioned in the slot, the slider moves the retention body from its lowered position to its raised position, whereby the retention body urges the blade radially outwardly thereby mating flanks of the root to flanks of the slot, while the part of the key portion still received in the keyway retains the root axially in the slot.

15. A device according to claim 14 , wherein the normal to the plane of each arc is substantially perpendicular to the radial direction.

16. A device according to claim 14 , wherein the arc-shaped surface of the retention body is a convex surface.

17. A device according to claim 14 , wherein the arc-shaped surface of the retention body is a concave surface.

18. A device for chocking and retaining a dovetail root of a blade of a gas turbine engine in a corresponding axially-extending slot in the rim of a disc, the device including:
a retention body having:
a key portion receivable in a keyway formed in the base of the slot,
a mating portion for mating with a complementary mating portion of the root to prevent relative axial movement between the retention body and the root, and
the retention body having a lowered position in which the key portion is received sufficiently deeply in the keyway to allow the root to be positioned in the slot without interference from the retention body, and a raised position in which, after the root is positioned in the slot, a part of the key portion is still received in the keyway while the mating portion mates with the complementary mating portion of the root;

a slider which is axially insertable in the slot, the slider having one or more chock springs which are arranged to act, in use, on the root to also urge the blade radially outwardly;
wherein the slider and the retention body are configured so that, on axial insertion of the slider in the slot after the root is positioned in the slot, the slider moves the retention body from its lowered position to its raised position, whereby the retention body urges the blade radially outwardly thereby mating flanks of the root to flanks of the sl

Assignees

• Rolls Royce Plc

Inventors

• Benson Christopher

Classifications

• F01D5/323 Primary

  Locking of axial insertion type blades by means of a key or the like parallel to the axis of the rotor · CPC title

• F05D2260/96

  Preventing, counteracting or reducing vibration or noise · CPC title

• F05D2300/434

  Polyimides, e.g. AURUM · CPC title

• F01D5/3053

  by means of pins · CPC title

• F01D5/282

  Selecting composite materials, e.g. blades with reinforcing filaments · CPC title