Ceramic matrix composite assembly with compliant pin attachment features

Abstract

An assembly adapted for use in a gas turbine engine. The assembly includes a support component comprising metallic materials, a supported component comprising ceramic matrix composite materials, and an attachment pin configured to couple the supported component to the support component. The attachment pin includes compliant features to distributes loads applied to the supported component.

Claims

1. A turbine shroud adapted to be mounted outward of blades included in a turbine wheel assembly and adapted to block gases from passing over the blades, the turbine shroud comprising a carrier segment comprising metallic materials and configured to be mounted to other metallic components within a gas turbine engine, a blade track segment comprising ceramic matrix composite materials, the blade track segment including a runner that extends partway around a central axis and a first attachment feature with an eyelet formed through the first attachment feature, the eyelet is formed to include a chamfer around an insertion end of the eyelet, and an attachment pin configured to couple the blade track segment to the carrier segment, the attachment pin including a shaft that extends through the eyelet in the first attachment feature of the blade track segment, and a compliant wrap that extends around a portion of the shaft, wherein the compliant wrap has split construction so that the complaint wrap is capable of being assembled over the shaft, wherein the attachment pin includes locator shoulders that extend out from the shaft and the compliant wrap is arranged along a length of the attachment pin between the locator shoulders.

2. The turbine shroud of claim 1, wherein the compliant wrap is located in the eyelet of the first attachment feature of the blade track segment.

3. The turbine shroud of claim 1, wherein the carrier segment is formed to include a mount aperture, the first attachment feature of the blade track segment is located so that the eyelet of the blade track segment aligns with the mount aperture, and the attachment pin extends into the mount aperture.

4. The turbine shroud of claim 3, wherein the compliant wrap includes a plurality of wrap sections, the plurality of wrap sections including a first wrap section arranged between the locator shoulders and a second wrap section arranged in the mount aperture.

5. The turbine shroud of claim 1, wherein the compliant wrap has greater material compliance than the shaft so that loads applied onto the blade track segment by the attachment pin are distributed along the first attachment feature of the blade track segment.

6. The turbine shroud of claim 1, wherein an undercut is formed in the shaft of the attachment pin and the undercut is axially aligned with the insertion end of the eyelet of the blade track segment.

7. A turbine shroud adapted for use in a gas turbine engine, the turbine shroud comprising a carrier comprising metallic materials, a blade track segment comprising ceramic matrix composite materials, the blade track segment including a runner that extends partway around a central axis and a first attachment feature with an opening formed through the first attachment feature, and an attachment pin configured to couple the blade track segment to a carrier segment, the attachment pin including a shaft formed to include undercuts along the shaft to avoid edge loading of the blade track segment and the shaft extending through the opening in the first attachment feature of the blade track segment, and a compliant wrap that extends around a portion of the shaft, wherein the compliant wrap has greater material compliance than the shaft.

8. The turbine shroud of claim 7, wherein the first attachment feature includes chamfers at an insertion end of the opening of the first attachment feature.

9. The turbine shroud of claim 7, wherein the compliant wrap has split construction configured for assembly over the shaft.

10. The turbine shroud of claim 7, wherein the carrier is formed to include a radially inward extending flange, the radially inward extending flange includes an aperture, and the first attachment feature of the blade track segment is located so that the opening of the blade track segment aligns with the aperture of the radially inward extending flange, and the attachment pin extends into the aperture.

11. The turbine shroud of claim 10, wherein the attachment pin includes locator shoulders that extend out from the shaft and the compliant wrap is arranged along a length of the attachment pin between the locator shoulders.

12. The turbine shroud of claim 11, wherein the compliant wrap includes a plurality of wrap sections, the plurality of wrap sections including a first wrap section arranged between the locator shoulders and a second wrap section arranged in the aperture included in the carrier.

13. The turbine shroud of claim 7, wherein the shaft includes a recessed portion that extends radially into the shaft along an axial portion of the shaft, and the compliant wrap is located in the recessed portion.

14. The turbine shroud of claim 7, wherein the blade track segment includes a second attachment feature spaced circumferentially apart from the first attachment feature, and a second attachment pin that extends through an opening in the second attachment feature.

15. A turbine shroud radially encasing a turbine in a gas turbine engine, the turbine shroud comprising a carrier including a body plate and a support flange extending radially inward from the body plate, the support flange formed to define a mount aperture, a blade track segment comprising ceramic matrix composite materials, the blade track segment including a runner that extends partway around a central axis and a first attachment feature with an eyelet formed through the first attachment feature, the eyelet is formed to include a chamfer with an axially facing surface of the first attachment feature that faces the support flange of the carrier, and an attachment pin including a shaft that is configured to couple the blade track segment to the carrier, the attachment pin extending into the eyelet of the blade track segment through the chamfer, wherein the shaft is formed to include undercuts along the shaft that are axially aligned with the chamfer of the eyelet in the first attachment feature.

16. The turbine shroud of claim 15, wherein the eyelet in the first attachment feature of the blade track segment is aligned with the mount aperture in the support flange of the carrier, and the attachment pin extends through the eyelet and into the mount aperture.

17. The turbine shroud of claim 15, wherein the support flange is integral with the body plate of the carrier.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a cut-away perspective view of a gas turbine engine showing that the exemplary engine includes a fan driven by an engine core having a compressor, a combustor, and a turbine;

(2) FIG. 2 is a partial cross-sectional view of the gas turbine engine of FIG. 1 showing the arrangement of a segmented turbine shroud radially outward of blades included in a turbine wheel assembly to suggest that the turbine shroud blocks gasses from passing over the blades without interacting with the blades;

(3) FIG. 3 is a detail view of a portion of FIG. 2 showing a turbine shroud segment that includes a carrier segment made from metallic materials, a blade track segment made from ceramic matrix composite materials, and attachment pins with compliant features that couples the turbine shroud segment to the carrier segment while spreading out mounting/pressure loads created along the attachment pins;

(4) FIG. 4 is a further detail view of FIGS. 2 and 3 showing that each attachment pin includes a shaft, locator shoulders that extend out from the shaft to engage the blade track segment, and compliant wraps that extend around the shaft adjacent to the locator shoulders to distribute mounting load along the length of the attachment pin;

(5) FIG. 5 is an exploded perspective assembly view of the blade track segment and the attachment pins showing that the blade track segment includes a runner adapted to face high temperature gasses in the turbine and attachment posts formed to include eyelets sized to receive the attachment pins;

(6) FIG. 6 is a view similar to FIG. 3 including a second turbine shroud segment adapted for use in the gas turbine engine of FIG. 1 showing a turbine shroud segment that includes a carrier segment made from metallic materials, a blade track segment made from ceramic matrix composite materials, and attachment pins with compliant features that couples the turbine shroud segment to the carrier segment while spreading out mounting/pressure loads applied on the ceramic matrix composite of the blade track segment;

(7) FIG. 7 is a detail view of FIG. 6 showing that each attachment pin includes a shaft, locator shoulders that extend out from the shaft to engage the blade track segment, and a compliant wrap that extend around the shaft between the locator shoulders to distribute mounting load along the attachment feature of the ceramic matrix composite blade track segment;

(8) FIG. 8 is a view similar to FIG. 3 including a third turbine shroud segment adapted for use in the gas turbine engine of FIG. 1 showing a turbine shroud segment that includes a carrier segment made from metallic materials, a blade track segment made from ceramic matrix composite materials, and attachment pins with compliant features that couples the turbine shroud segment to the carrier segment while spreading out mounting/pressure loads applied on the ceramic matrix composite of the blade track segment; and

(9) FIG. 9 is a detail view of FIG. 8 showing that each attachment pin includes a shaft, locator shoulders that extend out from the shaft to engage the blade track segment, and a compliant wrap that extend around the shaft between the locator shoulders, and further showing undercuts formed adjacent to the locator shoulders to avoid edge loading the ceramic matrix composite of the blade track segment;

(10) FIG. 10 is a view similar to FIG. 3 including a fourth turbine shroud segment adapted for use in the gas turbine engine of FIG. 1 showing a turbine shroud segment that includes a carrier segment made from metallic materials, a blade track segment made from ceramic matrix composite materials, and attachment pins with compliant features that couples the turbine shroud segment to the carrier segment while spreading out mounting/pressure loads applied on the ceramic matrix composite of the blade track segment;

(11) FIG. 11 is a detail view of FIG. 10 showing that each attachment pin includes a shaft, locator shoulders that extend out from the shaft to engage the blade track segment, support shoulders that extend out from the shaft to engage the metallic carrier segment, and a compliant wrap that extend around the shaft between the locator shoulders, and further showing slots formed in the shaft to provide compliance in the shaft in portions directly engaged with the carrier segment; and

(12) FIG. 12 is a perspective view of the attachment pin of FIGS. 10 and 11 showing the slots formed in the support shoulders and the shaft of the attachment pin.

DETAILED DESCRIPTION OF THE DRAWINGS

(13) For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to a number of illustrative embodiments illustrated in the drawings and specific language will be used to describe the same.

(14) An illustrative aerospace gas turbine engine 10 includes a fan 12, a compressor 14, a combustor 16, and a turbine 18 as shown in FIG. 1. The fan 12 is driven by the turbine 18 and provides thrust for propelling an air vehicle. The compressor 14 compresses and delivers air to the combustor 16. The combustor 16 mixes fuel with the compressed air received from the compressor 14 and ignites the fuel. The hot, high-pressure products of the combustion reaction in the combustor 16 are directed into the turbine 18 to cause the turbine 18 to rotate about a central axis 11 and drive the compressor 14 and the fan 12.

(15) The turbine 18 includes at least one turbine wheel assembly 19 and a turbine shroud 20 positioned to surround the turbine wheel assembly 19 as shown in FIGS. 1 and 2. The turbine shroud 20 is coupled to an outer case 30 of the gas turbine engine 10. The turbine wheel assembly 19 includes a plurality of blades 13 coupled to a rotor disk for rotation therewith. The hot, high pressure combustion products from the combustor 16 are directed toward the blades 13 of the turbine wheel assemblies 19 along a flow path 17. The blades 13 are in turn pushed by the combustion products to cause the turbine wheel assembly 19 to rotate; thereby, driving the rotating components of the compressor 14 and/or the fan 12.

(16) The turbine shroud 20 extends around the turbine wheel assembly 11 to block combustion products from passing over the blades 13 without pushing the blades 13 to rotate as suggested in FIG. 2. In the illustrative embodiment, the turbine shroud 20 is made up of a number of shroud segments 22, one of which is shown in FIGS. 3 and 4, that extend only part-way around the central axis 11 and cooperate to surround the turbine wheel assembly 11. The shroud segments 22 are sealed against one another, such as by strip seal members, to provide a continuous turbine shroud 20. In certain embodiments, certain components of the turbine shroud 20 are segmented while other components are annular and non-segmented.

(17) Each shroud segment 22 includes a carrier segment 24, a blade track segment 26, and an attachment pin 28 configured to couple the blade track segment 26 to the carrier segment 24 as shown in FIGS. 3 and 4. The carrier segment 24 is a metallic support component configured to interface with other metallic components spaced from the primary gas path of the engine 10. The blade track segment 26 is a ceramic matrix composite component configured to directly face the high temperatures of the primary gas path. The attachment pin 28 includes compliant features (e.g. compliant wrap 54) that distributes loads across the blade track segment 26 to facilitate incorporation of ceramic matrix composites in this component.

(18) The carrier segment 24 included in each shroud segment 22 is coupled to an outer case 30 of the engine 10 as shown in FIG. 2. Each carrier segment 24 illustratively includes a body plate 32, hangers 34, and support flanges 35, 36 as shown in FIG. 3. The body plate 32 extends partway around the axis 11. The hangers 34 extend radially outward from the body plate 32 and engage the outer case 30 to couple the turbine shroud segment 22 to the rest of the engine 10. A forward support flange 35 extends radially inward from the body plate. An aft support flange 36 is spaced aft of the forward support flange 35 along the axis 11 and extends radially inward from the body plate 32. Each of the support flanges 35, 36 is formed to include a cantilevered bore tube 91, 92 with a mount aperture 37 sized to receive forward/aft portions of the attachment pin 28 as shown in FIG. 3

(19) The blade tracks segment 26 of each shroud segment 22 comprises ceramic matrix composite materials as suggested in FIGS. 2 and 4. The blade track segment 26 is held in place adjacent to tips of turbine blades 13 to block combustion products from passing over the blades 13 without pushing the blades 13 to rotate as suggested in FIG. 2. The blade track segment 26 is illustratively formed to include a runner 40 and an attachment 42. The runner 40 arcuate and extends partway around axis 11 adjacent to turbine blades 13. The attachment 42 extends radially outward from the runner 40 to provide structure for coupling the blade track segment 26 to the carrier segment 24.

(20) In the illustrative embodiment, the attachment 42 of the blade track segment 26 includes two attachment posts 51, 52 as shown in FIG. 5. The attachment posts 51, 52 are circumferentially spaced apart from one another and extend part-way across the runner 40 in the axial direction parallel to the central axis 11. Each attachment post 51, 52 is formed to include an eyelet 54 sized to receive an attachment pin 28. When a segment 22 is assembled, the attachment posts 51, 52 are located so that the eyelets 54 are aligned with mount apertures 37 of the support flanges 35, 36 included in the carrier segment 24 and attachment pins 28 are inserted through apertures 37/eyelets 54 to couple the blade track segments 26 to the carrier segments 24.

(21) The attachment pins 28 are configured to distribute mounting and pressure loads applied to the attachment 42 of the blade track segment 26 to account for material properties of the ceramic matrix composite. Each attachment pin 28 illustratively includes a shaft 60, locator shoulders 61, 62, and a compliant wrap 64 as shown in FIGS. 4 and 5. The shaft 60 extends along an axis 65 through forward/aft support apertures 37 and eyelet 54. The locator shoulders 61, 62 extend out from the shaft 60 and directly engages a corresponding attachment post 51, 52 along the interior of the eyelet 54 to provide a hard stop location for the blade track segment 26. The compliant wrap 64 extends around the shaft 60 along a portion of the shaft 64 arranged inside the eyelet 54. The compliant wrap 64 has greater material compliance than the shaft 60 so that loads applied onto the blade track segment 26 by the attachment pin 28 are distributed along the attachment 42 of the blade track segment 26.

(22) The shaft 60 and the locator shoulders 61, 62 are illustratively made from metallic materials and are integrally formed as a one-piece component as shown in FIGS. 4 and 5. The shaft 60 illustratively has a round, tubular shape but in other embodiments may have a different cross-sectional shape (rectangular, oval, etc.) and may be solid.

(23) The compliant wrap 64 includes a plurality of wrap sections 71, 72, 73 as shown in FIG. 5. A wrap section 71 is arranged forward of the locator shoulders 61, 62 and is located in the aperture 37 of the forward support flange 35 included the carrier segment 24 to distribute loads therein. Another wrap section 72 is arranged between the locator shoulders 61, 62 and is located in the eyelet 54 of the blade track segment 26. Yet another wrap section 73 is arranged aft of the locator shoulders 61, 62 and is located in the aperture 37 of the aft support flange 36 included in the carrier segment 26 to distribute loads.

(24) When mounting ceramic matrix composite (CMC) components in turbine engines (i.e. engine 10), difficulties can arise when attempting to mitigate highly concentrated contact loads. One means of doing so includes the use of high-temperature capability complaint materials.

(25) As shown in FIGS. 2-5, the complaint layer or wrap 64 enables a predictable distribution of load between the CMC blade track segment 26 and the pin 28 at the bore of the eyelet 54. This would serve to reduce stresses associated with the mounting of the blade track segment 26 in the engine 10.

(26) The compliant layer 64 pieces 71, 72, 73 are shown with split construction so the arms of the pieces 71, 72, 73 can be spread apart and assembled over the diameter of the shaft 60, prior to assembly into the bore of the eyelet 54. Optionally, the end pieces 71, 73, and perhaps even the central piece 72, could be full hoops if desired.

(27) Possible compliant wraps 64 could be a high temperature, flexible material such as INTERAM® material available from 3M®. The compliant material may be wrapped in foil to improve durability. Another possible compliant wrap 64 would be a high temperature sheet alloy such as Waspaloy or Rene-41 which is formed into a split wave spring ring (undulations running circumferentially).

(28) A second embodiment of a turbine shroud segment 22A adapted for use in a turbine shroud is shown in FIGS. 6 and 7. The second embodiment is substantially similar to the turbine shroud segment 22 shown and described in relation to FIGS. 1-5. In view of this similarity, common reference numbers indicate similar features.

(29) Unlike turbine shroud segment 22, the turbine shroud segment 22A does not include compliant wrap pieces that interface with the carrier segment 24 as shown in FIGS. 6 and 7. Rather, compliant wrap 64A of attachment pin 28A is sized and arranged in eyelet 54 of blade track segment 26 to engage only the blade track segment 26. Accordingly, apertures 37A of the forward and aft support flanges 35, 36 included in the carrier segment 24 are sized to directly engage the shaft 60 of the attachment pin 28A.

(30) In this embodiment, the flanges 35, 36 of the carrier segment 24 are each optionally formed to include a cantilevered bore tube 91A, 92A and an engagement shoulder 93A, 94A. The cantilevered bore tubes 91A, 92A have some flexibility relative to the rest of the carrier segment 24. The engagement shoulders 93A, 94A extend radially into the cantilevered bore tubes 91A, 92A and directly engage the shaft 60A of the attachment pin 28A. Accordingly, the cantilevered bore tubes 91A, 92A provide some compliance for the assembly segment 22A.

(31) A third embodiment of a turbine shroud segment 22B adapted for use in a turbine shroud is shown in FIGS. 8 and 9. The third embodiment is substantially similar to the turbine shroud segment 22 shown and described in relation to FIGS. 1-5. In view of this similarity, common reference numbers indicate similar features.

(32) Unlike turbine shroud segment 22, the turbine shroud segment 22B does not include compliant wrap pieces that interface with the carrier segment 24 as shown in FIGS. 8 and 9. Rather, compliant wrap 64B of attachment pin 28B is sized and arranged in eyelet 54 of blade track segment 26 to engage only the blade track segment 26. Accordingly, apertures 37B of the forward and aft support flanges 35, 36 included in the carrier segment 24 are sized to directly engage shaft 60B of the attachment pin 28B. Indeed, in the embodiment of FIGS. 8 and 9, the shaft 60B of the attachment pin 28B is sized such that the diameter of the shaft 60B generally matches the diameter of the locator shoulders 61, 62 to rigidify the shaft 60B at its interface with the carrier segment 24.

(33) Optionally, undercuts 80B are formed in the shaft 60B of the attachment pin 28B as shown in FIG. 9. A first undercut 80B is located in a first location along the attachment pin 60B between the locator shoulders 61, 62 and a forward portion of the shaft 60B. A second undercut 80B is located in a second location along the attachment pin 60B between the locator shoulders 61, 62 and an aft portion of the shaft 60B.

(34) The embodiment of FIGS. 8 and 9 also show that the attachment feature 42 of the blade track segment 26 may be formed to include a chamfer 90″ around an insertion end of the eyelet 54. The chamfer 90B is illustratively shaped to compress the compliant wrap 64B when the attachment pin 28B is inserted into the insertion end of the eyelet 54.

(35) The compliant wrap 64 can be assembled into the blade track segment 26 eyelet 54 via two methods. The first would be by a large, gently sloped (small included angle) lead in chamfer 90B in the blade track segment 26 eyelet 54 end. The second would be an assembly tool (not shown) that would be placed against one end of the blade track segment 26 eyelet 54 that would pre-compress the compliant wrap 64 to just above the eyelet 54 diameter with a very gentle cone angle prior to entering the eyelet 54.

(36) In this embodiment, the flanges 35, 36 of the carrier segment 24 are each optionally formed to include a cantilevered bore tube 91B, 92B and an engagement shoulder 93B, 94B. The cantilevered bore tubes 91B, 92B have some flexibility relative to the rest of the carrier segment 24. The engagement shoulders 93B, 94B extend radially into the cantilevered bore tubes 91B, 92B and directly engage the shaft 60B of the attachment pin 28B. Accordingly, the cantilevered bore tubes 91B, 92B provide some compliance for the assembly segment 22B.

(37) A fourth embodiment of a turbine shroud segment 22C adapted for use in a turbine shroud is shown in FIGS. 10-12. The fourth embodiment is substantially similar to the turbine shroud segment 22 shown and described in relation to FIGS. 1-5. In view of this similarity, common reference numbers indicate similar features.

(38) Unlike turbine shroud segment 22, the turbine shroud segment 22C does not include compliant wrap pieces that interface with the carrier segment 24 as shown in FIGS. 10 and 11. Rather, compliant wrap 64C of attachment pin 28C is sized and arranged in eyelet 54 of blade track segment 26 to engage only the blade track segment 26. Apertures 37C of the forward and aft support flanges 35, 36 included in the carrier segment 24 are sized to directly engage shoulders 95C, 96C that extend out from the shaft 60C of the attachment pin 28C.

(39) Optionally, slots 99C are formed in the ends of the shaft 60C included in the attachment pin 28C. The slots 99C provide compliance of the pin 28C at the interface with the carrier segment 24. It will be appreciated that such slots may be included in any of the attachment pins described in this paper.

(40) While the present disclosure specifically teaches the use of a mounting system in a turbine shroud having ceramic matrix composite blade track segments, it is contemplated that other assemblies may benefit from features of the specific design described. In one example, the mounting system and/or other features of the present disclosure may be incorporated into a combustor having ceramic matrix composite liner tiles that surround the combustion chamber. In another example, the mounting system and/or other features of the present disclosure may be incorporated into an exhaust assembly having ceramic matrix composite heat shields. In yet another example, the mounting system and/or other features of the present disclosure may be incorporated into heat shields for spacecraft. Moreover, the teachings of the present disclosure may be applied to any assembly facing high temperature operating conditions.

(41) While the disclosure has been illustrated and described in detail in the foregoing drawings and description, the same is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments thereof have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.