US3784320A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and means for retaining ceramic turbine blades
Assignee: MTU Aero Engines AG
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Filing: 1972-02-22
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Granted: 1974-01-08
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Expires: 1992-02-22
Abstract
Abstract A method and means for retaining ceramic turbine blades in steel rotors using metallic felt shims interposed between the edges of the blade root and side walls of a slot formed in the rotor. The metallic felt shims are formed of very thin metallic fibers sintered together to form a thin sheet of felt material. This sintered felt sheet is then compressed beyond its first plastic limit, at which point it again becomes elastic, exhibiting favorable elastic properties for absorbing the relatively large rotative and centrifugal forces between the rotor and blade during use. Since the force between blade and rotor transfer is almost exclusively through elastic deformation of the shim means, the friction coefficients between the shim and rotor or blade structure need not be precisely controlled. The shim is fixed to the rotor structure by brazing or the like. The predeformed metal felt material also acts as a heat insulator to prevent or inhibit the transfer of high blade temperatures and heat to the rotor.
Inventors
- 👤 A Rossmann
- 👤 W Hoffmuller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 02:24
CPC Classifications
F; F01; F01D; F01D5/00; F01D5/30; F01D5/3092; F01D5/12; F01D5/28; F01D5/284; F01D5/3084
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
156 words
An arrangement for retaining turbine blades, especially ceramic turbine blades, in a circumferentially extending slot of a rotatable rotor, especially a steel rotor, comprising: wall means forming said slot including inclined portions with a surface component facing inwardly toward the axis of rotation of the rotor, surface means on said blade arranged in said slot approximately parallel to said inclined portions at a small spacing from said inclined portions, and metallic shim means positioned between the inclined portions and the surface means, said shim means being constructed of a sintered metal felt material which has been predeformed beyond a first plastic limit so that it exhibits highly elastic properties for elastically absorbing the large centrifugal forces between the rotor and blade during use whereby the relative movement of the blade and rotor is primarily a function of the elasticity of the shim, said shim means also forming a thermal insulation between the rotor and the blade.
Claim 2
Dependent Claim
156 words
An arrangement for retaining turbine blades, especially ceramic turbine blades, in a circumferentially extending slot of a rotatable rotor, especially a steel rotor, comprising: wall means forming said slot including inclined portions with a surface component facing inwardly toward the axis of rotation of the rotor, surface means on said blade arranged in said slot approximately parallel to said inclined portions at a small spacing from said inclined portions, and metallic shim means positioned between the inclined portions and the surface means, said shim means being constructed of a sintered metal felt material which has been predeformed beyond a first plastic limit so that it exhibits highly elastic properties for elastically absorbing the large centrifugal forces between the rotor and blade during use whereby the relative movement of the blade and rotor is primarily a function of the elasticity of the shim, said shim means also forming a thermal insulation between the rotor and the blade.
Claim 3
Dependent Claim
23 words
An arrangement according to claim 1, wherein said shim means is fixedly attached to one of said inclined portions and said surface means.
Claim 4
Dependent Claim
19 words
An arrangement according to claim 1, wherein said shim means is fixedly attached to said inclined portions by brazing.
Claim 5
Dependent Claim
22 words
An arrangement according to claim 2, wherein said shim means is approximately one millimeter thick after predeformation and without any compressive loads.
Claim 6
Dependent Claim
48 words
An arrangement according to claim 2, wherein said shim means is composed of metal fibers approximately 6 to 15 Mu m in diameter which are sintered by the application of high heat, pressure and reduced atmosphere to form a metal felt structure which is then predeformed by compression.
Claim 7
Dependent Claim
38 words
An arrangemenT according to claim 5, wherein said metal fibers consist of 1.5 percent Co, 22 percent Cr. 9 percent Mo, 0.6 percent W, 18 percent Fe, 0.10 percent C, 1.0 percent Si, 1.0 percent Mn, balance Ni.
Claim 8
Dependent Claim
29 words
An arrangement according to claim 2, wherein further shim means of similar material are provided between the radially innermost end of the blade and the bottom of the slot.
Claim 9
Dependent Claim
23 words
An arrangement according to claim 1, wherein said slot and the radially inner end of said blade are of corresponding triangular cross-section shapes.
Claim 10
Independent Claim
124 words
A method for retaining turbine blades, especially ceramic turbine blades, in a circumferentially extending slot of a rotatable rotor, especially a steel rotor, comprising: forming the slot and the surface of the blade so as to have respective parallel surfaces facing one another with the slot surface having a surface component facing relatively inwardly toward the axis of rotation of the rotor, constructing shim means of sintered metal felt, predeforming the shim means beyond a first plastic limit so that the shim means exhibits elastic properties and high strength, and placing the predeformed shim means between the respective parallel surfaces of said slot and blade whereby the shim means effectively elastically absorbs the transfer of centrifugal forces between said rotor and blade during use.
Claim 11
Independent Claim
124 words
A method for retaining turbine blades, especially ceramic turbine blades, in a circumferentially extending slot of a rotatable rotor, especially a steel rotor, comprising: forming the slot and the surface of the blade so as to have respective parallel surfaces facing one another with the slot surface having a surface component facing relatively inwardly toward the axis of rotation of the rotor, constructing shim means of sintered metal felt, predeforming the shim means beyond a first plastic limit so that the shim means exhibits elastic properties and high strength, and placing the predeformed shim means between the respective parallel surfaces of said slot and blade whereby the shim means effectively elastically absorbs the transfer of centrifugal forces between said rotor and blade during use.
Claim 12
Dependent Claim
22 words
A method according to claim 9, wherein the step of predeforming the shim means includes compressing the shim means in a press.
Claim 13
Dependent Claim
46 words
A method according to claim 9, wherein the step of predeforming the shim means includes compressing the shim means by placing it into a rotor and blade assembly and rotating said rotor to cause relative movement of said rotor and blade to compress the shim means.
Claim 14
Dependent Claim
18 words
A method according to claim 9, further comprising the step of fixing said shim means to said rotor.
Claim 15
Dependent Claim
36 words
A method according to claim 9, further comprising the step of positioning a predeformed shim means between the radially innermost end of the blade and the bottom of the slot for supporting the blade at rest.
Claim 16
Dependent Claim
56 words
A method according to claim 9, wherein said shim means is composed of metal fibers approximately 6 to 15 Mu m in diameter, and wherein said step of constructing the shim means includes sintering these metal fibers by the application of high heat, pressure and reduced atmosphere which effectively connects the fibers at their contact points.
Claim 17
Dependent Claim
38 words
A method according to claim 14, wherein said metal fibers consist of 1.5 percent Co, 22 percent Cr, 9 percent Mo, 0.6 percent W, 18 percent Fe, 0.10 percent C, 1.0 percent Si, 1.0 percent Mn, balance Ni.
Claim 18
Dependent Claim
27 words
A method according to claim 9, wherein said shim means is compressed from a thickness of approximately 1.25 mm to approximately 1.00 mm during the predeforming step.
Claim 19
Dependent Claim
30 words
A shim for use in turbine rotor blade construction comprising a uniform metallic felt material consisting of sintered metallic fibers, said material having highly elastic properties and providing thermal insulation.
Claim 20
Dependent Claim
30 words
A shim for use in turbine rotor blade construction comprising a uniform metallic felt material consisting of sintered metallic fibers, said material having highly elastic properties and providing thermal insulation.
Claim 21
Dependent Claim
32 words
A shim according to claim 17, wherein said metallic fibers are approximately 6 to 15 Mu m in diameter and are sintered by the application of high heat, pressure and reduced atmosphere.
Claim 22
Dependent Claim
40 words
A shim according to claim 18, wherein said metallic felt material consists of 1.5 percent Co, 22 percent Cr, 9 percent Mo, 0.6 percent W, 18 percent Fe, 0.10 percent C, 1.0 percent Si, 1.0 percent Mn, and balance Ni.
Claim 23
Dependent Claim
23 words
A shim according to claim 17, wherein said metallic felt material is deformed beyond a first plastic limit to achieve the elastic properties.
References Cited (Backward Citations)
FR892785A
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US2317338A
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GB664986A
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US2874932A
Cited
GB753229A
Cited
FR1163439A
Cited
GB914548A
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US3317988A
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-07 | 1977-07-09 | 1978-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-07 | 1981-07-09 | 1982-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-07 | 1985-07-09 | 1986-01-08 | $7700.00 | Window Closed / Lapsed |