U.S. patent application number 10/277810 was filed with the patent office on 2004-12-23 for blade platforms for a rotor assembly.
This patent application is currently assigned to SNECMA MOTEURS. Invention is credited to Goga, Jean-Luc, Lamothe, Pierre.
Application Number | 20040258528 10/277810 |
Document ID | / |
Family ID | 8868645 |
Filed Date | 2004-12-23 |
United States Patent
Application |
20040258528 |
Kind Code |
A1 |
Goga, Jean-Luc ; et
al. |
December 23, 2004 |
BLADE PLATFORMS FOR A ROTOR ASSEMBLY
Abstract
A rotary assembly comprising a disk having recesses at its
periphery, a plurality of blades carried by the disk, each blade
having a blade root engaged in a corresponding recess of the disk,
and a plurality of fitted platforms each mounted on the disk
between two adjacent blades, each platform being a piece of sheet
metal of substantially omega section having two flanks
interconnected by a web and shaped so as to press against the side
walls of the bottom portions of two adjacent blades, with the end
portions of the flanks presenting respective setbacks which fit
closely to the outlines of one side of a blade root and of the
adjacent side of the wall of a recess in which the blade root is
received.
Inventors: |
Goga, Jean-Luc; (Champagne
Sur Seine, FR) ; Lamothe, Pierre; (Saint Paul Sur
Save, FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SNECMA MOTEURS
2 Boulevard du General Martial Valin
Paris
FR
75015
|
Family ID: |
8868645 |
Appl. No.: |
10/277810 |
Filed: |
October 23, 2002 |
Current U.S.
Class: |
416/193A |
Current CPC
Class: |
F01D 11/008 20130101;
Y02T 50/60 20130101; F05D 2230/90 20130101; F01D 5/3007 20130101;
F05D 2240/80 20130101; F05D 2230/20 20130101; F05D 2300/611
20130101; Y02T 50/673 20130101 |
Class at
Publication: |
416/193.00A |
International
Class: |
B63H 001/16 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 24, 2001 |
FR |
0113714 |
Claims
1. A rotary assembly comprising a disk having recesses at its
periphery, a plurality of blades carried by the disk, each blade
having a blade root engaged in a corresponding recess of the disk,
and a plurality of fitted platforms each mounted on the disk
between two adjacent blades, wherein each platform is a piece of
sheet metal of substantially omega section having two flanks
interconnected by a web and shaped so as to press against the side
walls of the bottom portions of two adjacent blades, with the end
portions of the flanks presenting respective setbacks which fit
closely to the outlines of one side of a blade root and of the
adjacent side of the wall of a recess in which the blade root is
received.
2. An assembly according to claim 1, wherein the web of each
platform includes a stiffener.
3. An assembly according to claim 1, wherein the flanks of each
platform are coated in an antiwear material.
4. An assembly according to claim 1, wherein each platform is made
from a single piece of folded sheet metal.
5. An assembly according to claim 1, wherein each platform is made
by folding two pieces of sheet metal and welding them together
along a generator line extending along the middle of the web of the
platform.
6. An assembly according to claim 1, wherein each platform is made
by folding three pieces of sheet metal and welding them together
along respective generator lines of each of the flanks of the
platform.
7. A platform for mounting blades in recesses of a disk, the
platform being constituted by a piece of sheet metal of
substantially omega section having two flanks interconnected by a
web and shaped so as to press against the side walls of the bottom
portions of two adjacent blades, the end portions of the flanks
presenting setbacks so that each of the setbacks engages between
one side of a blade root and the adjacent side of the wall of a
recess in which the blade root is received.
8. A platform according to claim 7, wherein its web includes a
stiffener.
9. A platform according to claim 7, wherein the flanks are coated
in an antiwear material.
10. A platform according to claim 7, the platform being made from
folded sheet metal.
11. A platform according to claim 1, wherein, said setbacks are
concave portions.
12. A platform according to claim 7, wherein said setbacks are
concave portions.
13. A platform according to claim 1, wherein, for each platform,
said end portions of said two flanks diverge inwardly from each
other.
14. A platform according to claim 7, wherein said end portions of
said two flanks diverge inwardly from each other.
15. A platform according to claim 1, wherein said two flanks have a
length so that said web between said two flanks does not contact
said disk.
16. A platform according to claim 7, wherein said two flanks have a
length so that said web between said two flanks does not contact
said disk.
17. A platform according to claim 1, wherein each of said end
portions of said flanks covers at least a portion of a bottom
surface of said blade root.
18. A platform according to claim 7, wherein each of said end
portions of said flanks covers at least a portion of a bottom
surface of said blade root.
19. A platform according to claim 1, wherein said two flanks
provide a seal between the disk and the blades.
20. A platform according to claim 7, wherein said two flanks
provide a seal between the disk and the blades.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a rotor assembly for an
airplane gas turbine engine. More particularly, it relates to blade
platforms for the fan portion of such an engine, but it is equally
applicable to platforms for mounting blades in other rotary
assemblies, e.g. in the compressor.
[0002] In known manner, the fan of a gas turbine engine comprises a
disk having angularly spaced-apart blades received so as to be
pivotable to a small extent. Each blade is connected to the two
blades adjacent thereto via force transmitter members (also
referred to as platforms) which serve under normal circumstances to
limit pivoting of the blades. These platforms also serve to protect
the disk and the blades of the fan, which parts are expensive.
[0003] At present, there are two types of blade platform for gas
turbine engine fans and they are made using the following
technologies:
[0004] platforms that are directly integrated with the blades for
straight fastenings; and
[0005] platforms fitted between the blades.
[0006] By way of example, for platforms fitted between the blades,
one known system consists in holding the platform, e.g. made of
aluminum, by means of pegs which are fixed on flanges of the fan
disk and to a cheek plate provided at the front of the disk. The
assembly is sealed by lateral gaskets of rubber which are pressed
and deformed against the blades by the centrifugal force that
results from the fan disk rotating.
[0007] That platform-holding system presents a major problem
associated with the platform balancing to be performed by the pegs,
and with controlling displacements between the pegs and the
platform.
[0008] Furthermore, the problems encountered in operation are
numerous, and in particular the following:
[0009] the sealing gaskets lift off;
[0010] the bushings of the holding pegs move in translation, in
spite of being clamped when the platform is assembled;
[0011] the pegs become loose relative to the flanges; and
[0012] there is a risk of corrosion.
[0013] In addition, problems of wear are observed on the bearing
surfaces of the blades and of the disk of the fan. In order to
resolve those problems, and more particularly the problem relating
to bearing surface wear, it is also known to re-machine the recess
of the disk in which the blade root is mounted, and to insert a
piece of metal that acts as shim (also referred to as
"tinsel").
[0014] Nevertheless, in spite of the presence of the shim, it is
still found that the deposit of varnish type antiwear material
lifts off from the bearing surfaces of the blades and of the fan
disk. Furthermore, reboring is an operation that is difficult and
time consuming.
OBJECT AND SUMMARY OF THE INVENTION
[0015] The present invention seeks to propose a platform fitted to
blades and a rotary assembly using such a platform while avoiding
the above drawbacks.
[0016] To this end, the invention provides a rotary assembly
comprising a disk having recesses at its periphery, a plurality of
blades carried by the disk, each blade having a blade root engaged
in a corresponding recess of the disk, and a plurality of fitted
platforms each mounted on the disk-between-two adjacent blades,
wherein each platform is a piece of sheet metal of substantially
omega section having two flanks interconnected by a web and shaped
so as to press against the side walls of the bottom portions of two
adjacent blades, with the end portions of the flanks presenting
respective setbacks which fit closely to the outlines of one side
of a blade root and of the adjacent side of the wall of a recess in
which the blade root is received.
[0017] This particular platform shape makes it possible both to
protect the blades and the disks, and also to provide sealing for
the assembly.
BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Other characteristics and advantages of the present
invention appear from the following description made with reference
to the accompanying drawings which show an embodiment having no
limiting character. In the figures:
[0019] FIG. 1 is a diagrammatic and fragmentary view of a platform
of the invention mounted on a fan disk of a gas turbine engine;
[0020] FIG. 2 is a perspective view of a platform constituting a
first embodiment of the invention; and
[0021] FIGS. 3A and 3B are perspective views respectively of a
second and of a third embodiment of a platform of the
invention.
DETAILED DESCRIPTION OF AN EMBODIMENT
[0022] In FIG. 1, reference 1 designates a rotary assembly of a gas
turbine engine, which assembly includes a disk 2. The rotary
assembly can be an engine fan, for example. The disk of the rotary
assembly is conventionally provided with a plurality of moving
blades 3 of aerodynamic profile which are regularly spaced apart
from one another around its entire periphery.
[0023] Each blade 3 has a dovetail-shaped root 4 which is mounted
in a recess 5 provided for this purpose in the disk 2 of the rotary
assembly 1. These recesses 5 are likewise dovetail-shaped, and of
dimensions that are slightly greater than those of a blade root 4.
The roots are thus mounted in the recesses with a certain amount of
play.
[0024] Furthermore, each blade 3 is connected near its root 4 to
each of the two blades that are adjacent thereto by means of
respective fitted platforms 6. A platform 6 thus serves to protect
the blades and the disks and to reconstitute an aerodynamic section
between the blades.
[0025] For this purpose, the platform 6 is shaped so as to be
received between two adjacent blades as shown in FIG. 1. In FIG. 2,
it can be seen more precisely that the platform 6 is a piece of
sheet metal of generally omega (.OMEGA.) shape having two flanks 7
and 8 interconnected by a web 11. The flanks are shaped so as to
press against the side walls 9 and 10 of the bottom portions of two
adjacent blades between which the platform is inserted.
[0026] Furthermore, on its side remote from the web 11, each flank
7, 8 is terminated by an end portion 12, 13 that becomes engaged
between one side 14 of a blade root 4 and the adjacent side 15 of
the wall of a recess 5 in which the blade root is received. More
precisely, the end portions 12, 13 of the platform flanks present
setbacks 16, 16' or concave portions which fit closely to the
outlines of a blade root side 14 and the corresponding side of its
housing in the disk 2.
[0027] By means of this particular shape, and because the root 4 of
each blade 3 is well received in the corresponding recess 5, it is
easy to control the radial position of the platform. The
centrifugal force that results from rotation of the disk causes the
flanks 7 and 8 of the platform 6 to tend to become pressed against
the side walls 9 and 10 of the bottom portions of the two blades
between which the platform is engaged, thereby providing good
sealing for the assembly at the periphery of the disk. There is
therefore no need to use sealing gaskets.
[0028] Naturally, the flanks 7 and 8 of the platform 6 are of
sufficient height between the root and the tip of the blade to
ensure that they are not subject to excessive deformation as could
result from the effects of centrifugal force. In addition, the
platform is made of a material which is elastically deformable so
as to ensure that it does not break under the effect of centrifugal
force. For example, it could be made out of aluminum or out of any
other similar material.
[0029] The platform 6 preferably includes a stiffener (not shown)
level with its web. The stiffener serves to avoid excessive
deformation under the effect of centrifugal force. It is in the
form of folded or welded sheet metal extending radially from one
end of the platform.
[0030] The flanks 7 and 8 of the platform 6 are advantageously
coated in an antiwear material of the varnish type, at least on
those faces that come into contact with the bottom portions of the
side walls 9 and 10 of the blades 3 and with the walls of the
recesses 5 in the disk 2.
[0031] The present invention also provides a blade platform 6 for a
gas turbine engine fan as described above.
[0032] Three different embodiments of a platform 6 of the present
invention are described briefly below.
[0033] In a first embodiment (FIG. 2), the platform 6 is made by
folding a single piece of aluminum or similar sheet material.
[0034] In a second embodiment (FIG. 3A), the platform 6 is made by
folding and welding together two sheet metal portions made of
aluminum or similar metal, the join being along a generator line 17
in the middle of the web 11 of the platform.
[0035] Finally, in a third embodiment (FIG. 3B), the platform is
made by folding and welding together three pieces of aluminum or
similar sheet metal along respective generator lines 18 and 18' of
the flanks 7 and 8 of the platform.
[0036] As described above, the present invention provides multiple
advantages, and in particular it serves to mitigate the problems
encountered with the platforms in conventional use. In particular,
the specific shape of the platform of the present invention
provides protection both to the blades and to the disks carrying
them, and also serves to seal the assembly.
* * * * *