IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
UP-0494176
(2006-07-27)
|
등록번호 |
US-7600978
(2009-10-28)
|
발명자
/ 주소 |
- Vance, Steven J.
- Morrison, Jay A.
|
출원인 / 주소 |
|
인용정보 |
피인용 횟수 :
10 인용 특허 :
10 |
초록
▼
A CMC airfoil (20) formed with CMC stitches (37) interconnected between opposed walls (26, 28) of the airfoil to restrain outward flexing of the walls resulting from pressurized cooling air within the airfoil. The airfoil may be formed of a ceramic fabric infused with a ceramic matrix and dried, and
A CMC airfoil (20) formed with CMC stitches (37) interconnected between opposed walls (26, 28) of the airfoil to restrain outward flexing of the walls resulting from pressurized cooling air within the airfoil. The airfoil may be formed of a ceramic fabric infused with a ceramic matrix and dried, and may be partially to fully cured. Then holes (32, 34) are formed in the opposed walls of the airfoil, and a ceramic stitching element such as ceramic fibers (36) or a ceramic tube (44) is threaded through the holes. The stitching element is infused with a wet ceramic matrix before or after threading, and is flared (38) or otherwise anchored to the walls (26, 28) to form a stitch (37) there between. The airfoil and stitch are then cured. If the airfoil is cured before stitching, a pre-tension is formed in the stitch due to relative curing shrinkage.
대표청구항
▼
The invention claimed is: 1. A method of forming a CMC airfoil, comprising: forming with a CMC material a leading edge, a trailing edge, a pressure wall between the leading and trailing edges, and a suction wall between the leading and trailing edges; forming a hole in the pressure wall and forming
The invention claimed is: 1. A method of forming a CMC airfoil, comprising: forming with a CMC material a leading edge, a trailing edge, a pressure wall between the leading and trailing edges, and a suction wall between the leading and trailing edges; forming a hole in the pressure wall and forming a generally opposed hole in the suction wall; and passing a bundle of ceramic fibers through the holes to form a stitch of ceramic fibers between the pressure and suction walls; wherein the forming step comprises impregnating CMC fabric with a first ceramic matrix, shaping the impregnated fabric to form the leading and trailing edges and the pressure and suction walls, and drying the impregnated fabric prior to the hole forming step; wherein the passing step further comprises infusing the ceramic fibers with a second ceramic matrix; and further comprising curing the stitched walls and the stitch together after the passing step; and at least partially curing the impregnated fabric prior to curing the stitched walls and the stitch together in order to generate a preload in the stitch due to differential curing shrinkage. 2. A method as in claim 1, further comprising forming the CMC stitch with a material different than the CMC material used to form the leading and trailing edges and the pressure and suction walls. 3. A method as in claim 1, wherein a plurality of holes are formed in the pressure and suction walls, and the bundle of ceramic fibers is continuously woven through the plurality of holes to form a plurality of stitches of ceramic fibers between the pressure and suction walls. 4. A method as in claim 1, further comprising after the passing step: filling an interior space between the pressure and suction walls with a flowable ceramic core material; and curing the airfoil, the stitch, and the core material together. 5. A method as in claim 1, further comprising; impregnating the bundle of ceramic fibers with a ceramic matrix; anchoring the stitch of ceramic fibers to the pressure and suction walls at each of the holes; and curing the stitch of impregnated ceramic fibers to form a reinforcement between the pressure and suction walls to restrain outward flexing of the pressure and suction walls. 6. A method as in claim 5, wherein the bundle of ceramic fibers comprises ceramic fibers oriented generally along a longitudinal axis of the bundle of ceramic fibers. 7. A method as in claim 5, wherein the bundle of ceramic fibers comprises a tube of ceramic fibers comprising first and second ends, and wherein the anchoring step comprises flaring each respective end of the tube of ceramic fibers against a respective outer surface of the pressure and suction walls proximate each of the respective holes. 8. A method as in claim 5, further comprising forming a countersunk area around each of the holes on an outer surface of the pressure and suction walls prior to the passing step, and wherein the anchoring step comprises flaring each respective end of the bundle of ceramic fibers against the respective countersunk areas. 9. A method as in claim 5, wherein the cured stitch of ceramic fibers has a cross sectional aspect ratio of less than 2:1. 10. A method as in claim 5, wherein the cured stitch has a generally circular cross sectional shape. 11. A CMC airfoil with an internal stitch formed by the method of claim 1. 12. A method of forming a CMC airfoil, comprising: forming with a CMC material a leading edge, a trailing edge, a pressure wall between the leading and trailing edges, and a suction wail between the leading and trailing edges; forming a hole in the pressure wall and forming a generally opposed hole in the suction wall; and passing a bundle of ceramic fibers through the holes to form a stitch of ceramic fibers between the pressure and suction walls; impregnating the bundle of ceramic fibers with a ceramic matrix; anchoring the stitch of ceramic fibers to the pressure and suction walls at each of the holes; and curing the stitch of impregnated ceramic fibers to form a reinforcement between the pressure and suction walls to restrain outward flexing of the pressure and suction walls; wherein the CMC airfoil is at least partly cured before the anchoring step, and the stitch of impregnated ceramic fibers is cured after the anchoring step, such that a curing shrinkage of the CMC stitch results in a pre-tensioning of the CMC stitch between the pressure and suction walls of the airfoil. 13. A method of forming a CMC airfoil, comprising: forming with a CMC material a leading edge, a trailing edge, a pressure wall between the leading and trailing edges, and a suction wall between the leading and trailing edges; forming a hole in the pressure wall and forming a generally opposed hole in the suction wall; and passing a bundle of ceramic fibers through the holes to form a stitch of ceramic fibers between the pressure and suction walls; impregnating the bundle of ceramic fibers with a ceramic matrix; anchoring the stitch of ceramic fibers to the pressure and suction walls at each of the holes; and curing the stitch of impregnated ceramic fibers to form a reinforcement between the pressure and suction walls to restrain outward flexing of the pressure and suction walls; wherein the bundle of ceramic fibers comprises a tube of ceramic fibers comprising first and second ends, and wherein the anchoring step comprises flaring each respective end of the tube of ceramic fibers against a respective outer surface of the pressure and suction walls proximate each of the respective holes. 14. A method of forming a CMC airfoil, comprising: forming with a CMC material a leading edge, a trailing edge, a pressure wall between the leading and trailing edges, and a suction wall between the leading and trailing edges; forming a hole in the pressure wall and forming a generally opposed hole in the suction wall; and passing a bundle of ceramic fibers through the holes to form a stitch of ceramic fibers between the pressure and suction walls; impregnating the bundle of ceramic fibers with a ceramic matrix; anchoring the stitch of ceramic fibers to the pressure and suction walls at each of the holes; curing the stitch of impregnated ceramic fibers to form a reinforcement between the pressure and suction walls to restrain outward flexing of the pressure and suction walls; and forming a countersunk area around each of the holes on an outer surface of the pressure and suction walls prior to the passing step, and wherein the anchoring step comprises flaring each respective end of the bundle of ceramic fibers against the respective countersunk areas. 15. A CMC airfoil comprising: a first CMC wall and a second CMC wall spaced apart from each other to define an interior space; and a stitch interconnected between the first CMC wall and the second CMC wall; a flare at each opposed end of the stitch disposed against a respective surface of the respective wall; and a layer of ceramic insulating material disposed over each respective wall and its respective flare. 16. A CMC airfoil as in claim 15, wherein the stitch comprises a bundle of ceramic fibers oriented generally along a longitudinal axis of the stitch, wherein the bundle of ceramic fibers is impregnated with a ceramic matrix and has a cross sectional aspect ratio of less than 2:1. 17. A CMC airfoil comprising: a first CMC wall and a second CMC wall spaced apart from each other to define an interior space; and a stitch interconnected between the first CMC wall and the second CMC wall; wherein the stitch comprises a braided tube of ceramic fibers impregnated with a ceramic matrix, and wherein the braided tube is flared at each end against a surface of the respective wall. 18. A CMC airfoil as in claim 17, further comprising a countersunk area formed in each respective wall, and the braided tube being flared at each respective end against the respective countersunk area. 19. A CMC airfoil as in claim 17, wherein the stitch is pre-stressed in tension between the walls. 20. A CMC airfoil as in claim 17, wherein the stitch is passed through a first hole in the first wall and a second hole in the second wall. 21. A CMC airfoil as in claim 17, further comprising a ceramic core disposed in the interior space and encasing the stitch. 22. A CMC airfoil as in claim 17, further comprising a layer of ceramic insulating material disposed over each respective wall and its respective flare.
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