Chocking and retaining device

Patent metadata

Field	Value
Publication number	US-10024178-B2
Application number	US-201615057528-A
Country	US
Kind code	B2
Filing date	Mar 1, 2016
Priority date	Mar 12, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 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, the root being mounted in the slot by insertion of a leading end of the root into a proximal end of the slot and then sliding the root towards a distal end of the slot. The device includes a first wedging body having a key portion receivable in a keyway formed at the distal end of the slot. The keyway restrains the first wedging body against movement in the axial direction. The first wedging body further has a first angled surface over which a correspondingly angled leading end surface of the root slides when the root is inserted in the slot to urge the leading end of the root radially outwardly.

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 root being mounted in the slot by insertion of a leading end of the root into a proximal end of the slot and then sliding the root towards a distal end of the slot, the device including:
a first wedging body having a key portion receivable in a keyway formed at the distal end of the slot, the keyway restraining the first wedging body against movement in the axial direction, and the first wedging body further having a first angled surface over which a correspondingly angled leading end surface of the root slides when the root is inserted in the slot to urge the leading end of the root radially outwardly; and
a second wedging body insertable into the proximal end of the slot between the inserted root and a base of the slot, the second wedging body having a second angled surface which, on insertion of the second wedging body, slides over a correspondingly angled trailing end surface of the root to urge the trailing end of the root radially outwardly;
whereby the angled surfaces of the wedging bodies cause the flanks of the root to mate with flanks of the slot while also retaining the root axially in the slot.

2. A device according to claim 1 , wherein the second wedging body has an extension at a leading end thereof, the extension entering the slot in advance of the second angled surface to locate between the angled surfaces, and the extension carrying one or more chock springs which are arranged to act on the root to also urge the blade radially outwardly.

3. A rotor assembly of a gas turbine engine, the assembly having:
a circumferential row of blades, each blade having a dovetail root which has angled leading and trailing end surfaces; and
a combination according to claim 2 , of a disc and a plurality of devices;
wherein the dovetail root of each blade is inserted in the corresponding axially-extending slot in the rim of the disc, and the second wedging body of each device is inserted into the proximal end of a respective one of the slots to chock and retain the dovetail root of the respective blade in the slot.

4. A gas turbine engine having the rotor assembly of claim 3 .

5. A device according to claim 1 , wherein the first wedging body has an extension which locates in the slot between the angled surfaces and carries one or more chock springs which are arranged to act on the root to also urge the blade radially outwardly.

6. A device according to claim 1 , wherein the wedging bodies have relatively compliant outer layers at the angled surfaces for enhanced contact of the wedging bodies with the root.

7. A device according to claim 1 , wherein one of the first and second wedging bodies has a linkage member which extends from that body to the other of the first and second wedging bodies, the device further having a fastener for connecting the other of the first and second wedging bodies to the linkage member and tensioning the linkage member.

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

9. 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 inserted in a corresponding axially-extending slot in the rim of the disc, and which has angled leading and trailing end surface; 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 at the distal end thereof, the key portion of the first wedging body of each device is received in a respective one of the keyways, and the second wedging body of each device is inserted into the proximal end of a respective one of the slots.

10. A gas turbine engine having the rotor assembly of claim 9 .

11. A combination of a disc and a plurality of devices for chocking and retaining dovetail roots of blades of a gas turbine engine in corresponding axially-extending slots in the rim of the disc, each root being mounted in a respective slot by insertion of a leading end of the root into a proximal end of the slot and then sliding the root towards a distal end of the slot;
wherein the disc includes a respective first wedging body integrally formed at the distal end of each slot, each first wedging body having a first angled surface over which a correspondingly angled leading end surface of the respective root slides when the root is inserted in the slot to urge the leading end of the root radially outwardly; and
wherein each device includes a second wedging body insertable into the proximal end of a respective one of the slots between the inserted root and a base of the slot, each second wedging body having a second angled surface which, on insertion of the second wedging body, slides over a correspondingly angled trailing end surface of the root to urge the trailing end of the root radially outwardly;
whereby the angled surfaces of the wedging bodies cause the flanks of the roots to mate with flanks of the slots while also retaining the roots axially in the slots.

12. A combination according to claim 11 , wherein each second wedging body has an extension at a leading end thereof, the extension entering the slot in advance of the second angled surface to locate between the angled surfaces, and the extension carrying one or more chock springs which are arranged to act on the root to also urge the blade radially outwardly.

13. A combination according to claim 11 , wherein each first wedging body has an extension which locates in the slot between the angled surfaces and carries one or more chock springs which are arranged to act on the root to also urge the blade radially outwardly.

14. A combination according to claim 11 , wherein the wedging bodies have relatively compliant outer layers at the angled surfaces for enhanced contact of the wedging bodies with the root.

15. A combination according to claim 11 , wherein one of the first and second wedging bodies has a linkage member which extends from that body to the other of the first and second wedging bodies, the device further having a fastener for connecting the other of the first and second wedging bodies to the linkage member and tensioning the linkage member.

16. A combination according to claim 11 , wherein each second wedging body has a stop at an end thereof which, in use, abuts a face of the disc or the root when the second wedging body is fully inserted in the slot to prevent over-insertion of the second wedging body.

Assignees

• Rolls Royce Plc

Inventors

• Benson Christopher

Classifications

• F05D2300/501

  Elasticity · CPC title

• F05D2260/96

  Preventing, counteracting or reducing vibration or noise · CPC title

• F05D2240/30

  Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor · CPC title

• F01D5/282

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

• F01D25/06

  for preventing blade vibration (means on blade-carrying members or blades F01D5/00) · CPC title