Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02811069 2013-03-11
1õ
ASSEMBLY OF A BLADE AND A COMPOSITE CARRIER, OBTAINED BY
SEALING
Field of the invention
[0001] The present invention relates to the technical field
of assemblies in the aeronautics sector, especially in
turbomachine compressor rectifiers. In particular, the
invention relates to a (stage of a) turbomachine compressor
rectifier made up of parts of an organic matrix composite
and made up of at least one blading subassembly
incorporating a mechanical assembly achieved by sealing.
[0002] In the context of the present invention, "sealing"
refers to the operation of fastening a part in a carrier by
means of a polymer element, which may include filler or not,
by mechanical locking and/or physicochemical interaction
with the carrier and/or the part to be attached.
Technological background and state of the art
[0003] In the current art, there are no turbomachine
compressor rectifiers made of composite material, but rather
only made of a metal material, for example titanium (TA6V),
steel or aluminum.
[0004] Furthermore, the blades generally have a single
material and profile on a same stage, possibly with small
variation in the calibration angle for aerodynamic reasons
on the last stage.
[0005] Lastly, the current systems rest on an outer shroud,
serving as a casing that performs most of the mechanical
functions, on blades attached to a first end on those outer
' CA 02811069 2013-03-11
. 2,
shrouds by various assembly technologies (welding, riveting,
bolting), and on relatively flexible inner shrouds attached
to the blades at a second end but that do not perform any
structural function.
[0006] Today, one of the major problems of the use of
composite parts lies in their interface with the outside.
The invention proposes a solution for assembling parts of
various natures: either "metal/composite" Or even
"composite/composite" hybrids, while using the smallest
possible quantity of metal attachment means, the latter
creating many issues (mass, differential expansion, etc.).
[0007] Document EP 1 493 901 discloses an assembly between
blades and the inner shroud of a compressor rectifier of an
aeronautic engine. Each blade passes through an opening
formed in the inner shroud and is attached thereto using
sealing cement containing an organic polymer adhesive.
[0008] Document EP 1 081 335 discloses a stator assembly
for a rotary machine and, more specifically, the assembly of
stator blades to inner shroud abradables. The stator
assembly comprises a thermoplastic shoulder provided with an
opening designed to receive the foot of the stator blade,
and the elastomer abradable connected to the shoulder using
adhesives.
[0009] Document DE 10 2009 010 613 discloses a method for
producing a closed strip around the blades of a turbine. A
strip of fibrous material is inserted into a housing
arranged at the free end of the blades, and a matrix is
infiltrated in the fibrous material of the strip and
polymerized to form a composite.
[0010] Document FR 1 431 558 discloses a blade structure
comprising a case and two concentric enclosures, an outer
CA 02811069 2013-03-11
3, -
enclosure and an inner closure, the latter being offset from
the outer enclosure by separating means. The blades are
mounted gripped in holes formed facing each other in both
enclosures. The blades may be welded, glued or fastened on
the outer enclosure, which is mounted gripped in an outer
case. In particular, all these parts of the blade structure
may be made of synthetic resin and glued to one another. The
blades may also be made of metal and welded on the outer
case.
Aims of the invention
[0011] The present invention aims to overcome the drawbacks
of the state of the art.
[0012] In particular, the invention aims to allow the
production of bladed rectifiers with a light weight and at a
low cost for all compressors whose rotor is made up of
discs, of a drum, or of other elements.
[0013] The invention also aims to allow the easy assembly
of rectifier blades with varied properties, so as to best
optimize the mechanical strength as well as the costs.
[0014] The invention also aims to allow the rectifier to be
easily assembled and disassembled, thereby favoring the in-
use maintenance aspects while limiting the number of metal
fastening elements.
[0015] The invention also aims to save time during the
assembly of the compressor.
[0016] The invention lastly aims to allow permanent and
non-deformable connection of the metal or OMC (organic
matrix composite) composite parts to parts made of OMC
composite.
CA 02811069 2013-03-11
. 1õ
Main characteristic elements of the invention
[0017] A first object of the present invention most
generally relates to a mechanical assembly in the
aeronautics field comprising:
- a part comprising an attachable end;
- a recess with a wall of an organic matrix composite or OMC
for receiving the part;
- a sealing composite comprising a thermoplastic or heat-
sealable material with between 0 and 70 wt % of a filler,
preferably with short fibers, forming a mechanical and/or
physicochemical connection between said part and the
recess with the OMC wall.
[0018] According to specific embodiments of the invention,
the mechanical assembly comprises at least one or a suitable
combination of the following features:
- said part is a blade;
- said part comprises one end (or foot) whose geometry
allows to optimize the mechanical connection;
- said part comprises a foot geometry;
- the recess with the OMC wall is a profiled carrier,
preferably in the shape of a "U";
- the organic matrix of the recess is made of a
thermoplastic or heat-sealable material;
- the material of the recess with the OMC wall and that of
the sealing composite are identical or chemically
compatible, so as to produce a chemical or physicochemical
attachment between them;
- the recess with the heat-sealable or thermoplastic OMC
wall is produced by a method selected from the group
consisting of compression molding, injection of
81632127
thermoplastic or heat-sealable matrix, heat sealing and
co-consolidation;
¨ the sealing composite to be injected is produced by a
method selected from the group consisting of injection of
= 5 thermoplastic or heat-sealable matrix with or= without
filler =and of compression molding.
[0019] A second object of the present invention relates to
a rectifier stage for a turbomachine compressor comprising a
mechanical assembly of a plurality of blades to a housing
with an OMC wall imparting structural rigidity to the
assembly, according to= the above principle, the blades each
comprising a foot, said recess with an= OMC wall and said
sealing composite cooperating to seal the feet of =the blades
in the recess.
[0020] According to specific embodiments of the invention,
the rectifier stage comprises at least one or a =suitable
combination of the following features:
¨ the mechanical assembly is in the form of a ring or of a
sector attached to an outer shroud of the rectifier stage
by means of mechanical fasteners;
¨ the mechanical fasteners are lock bo].ts;
¨ the blades are made of metal or composite material;
= ¨ the blades are made of titanium or aluminum.
[0:021] A third object of the invention relates to a
turbomachine compressor comprising= one or more rectifier
stages as described above.
CA 2811069 2017-09-27 =
81632127
5a
The present invention relates to a mechanical assembly in the
aeronautics field comprising: a part comprising an attachable
end; a recess with a wall comprising an organic matrix
composite (OMC) for receiving the part; a sealing composite
comprising a thermoplastic or heat-sealable material with
between 0 and 70 wt % of a filler, forming a mechanical and/or
physicochemical connection between said part and the OMC wall.
The present invention relates to a rectifier stage for a
turbomachine compressor comprising the mechanical assembly as
described above, wherein the assembly comprises a plurality of
said parts, each part being a blade, and wherein the assembly
further comprises a housing having the OMC wall imparting
structural rigidity to the assembly, the blades each comprising
a foot, said OMC wall and said sealing composite cooperating in
order to seal the feet of the blades in the recess.
The present invention relates to a turbomachine compressor
comprising one or more rectifier stages as described above.
Brief description of drawings
[0022] Figure 1 shows a perspective view of an assembly as in
the invention and the related parts.
CA 2811069 2017-09-27
CA 02811069 2013-03-11
= 6., ,
[0023] Figure 2 diagrammatically shows the composite
assembly of the invention, by thermoforming followed by
overinjection, in a side view and a front view,
respectively.
Key
1. Basic structural pattern
2. U-shaped profile
3. Blade
3A. Blade foot
4. Sealing material
Description of a preferred embodiment of the invention
[0024] The assembly as in a preferred embodiment of the
present invention, whose principle and parts are shown in a
perspective view in figure 1, is essentially made up of a
subassembly 1 obtained by the sealing of a mechanical type
between:
- a part 2, which is preferably profiled, still more
preferably in the shape of a "U," with a base of an
organic matrix composite (OMC) material that is heat-
sealable or thermoplastic, imparting structural rigidity
to the assembly, and
- a blade 3 made of an a priori non-specific material (metal
or composite) and comprising a foot whose geometry may
vary or be adapted as needed.
Other diagrammatic views of this assembly are shown in
figure 2.
[0025] According to the present invention, the composite
carrier with heat-sealable or thermoplastic matrix 2 may be
manufactured by any type of method allowing to obtain
CA 02811069 2013-03-11
7.
sufficient mechanical properties, such as for example:
compression molding, injection of a thermoplastic or heat-
sealable matrix, for example RTM (resin transfer molding),
thermoforming or co-consolidation, etc. However, the
invention is not limited to the use of a profiled part 2,
for example in the shape of a "U". Thus, a planar carrier
may also be considered.
[0026] The sealing fastening composite or sealing composite
or sealing material 4 has a base of a heat-sealable or
thermoplastic matrix with between 0 and 70% of fibers, for
example or preferably short fibers, and may be implemented
by a method for injecting a thermoplastic or heat-sealable
matrix or by compression molding. More generally, the filler
may be any suitable mineral or organic filler. Thus, the
matrix may nevertheless have a filler (with fibers) or not
have a filler (pure matrix, 0% fibers).
[0027] Still according to the invention, the particular
geometry of the foot of the blade 3A ensures that it is
positioned and maintainded in the structure (figure 2). The
blades 3 being sealed, the blade foot 3A is then embedded by
the fastening composite 4 mentioned above, which for example
fills the profiled part 2 and thereby ensures that the blade
3 is maintained.
[0028] The sealing or assembly technique used as in a
preferred embodiment of the invention for metal blades 3 is
illustrated more particularly and very diagrammatically in
figure 2. The structural part or carrier structure 2 is
provided by a U-shaped profile part 2 made of a
thermoplastic composite with long fibers obtained by
thermoforming (the opening of the "U" is oriented toward the
outside relative to the blade).
CA 02811069 2013-03-11
84. =
[0029] Thermoplastic resin with a short fiber filler 4 is
injected to fill the hollow volume that remains once the
foot of the blade 3A is positioned in the carrier structure
2.
[0030] Furthermore, in order to best satisfy the
aerodynamic constraints, material is over-injected at the
level of the areas that do not allow to obtain the geometry
by thermoforming (not shown). Filling with the sealing
material to produce the mechanical and/or physicochemical
connection is for example achieved in a second step or, if
possible, at the same time as the composite structural part
is produced.
[0031] According to the present invention, the material of
the U-shaped composite carrier 2 and the sealing material 4
are identical or chemically compatible (for example,
thermoplastic materials of the same nature), so as to
produce chemical attachment between them. The resulting
"material" connection ultimately amounts in only producing a
single homogenous part, which is an additional advantage in
terms of mechanical strength of the assembly.
[0032] According to still another preferred embodiment of
the invention, the subassembly 1 belonging to the rectifier
stage is in the shape of a ring or of a sector fastened to
an outer shroud or to a case by means of mechanical
fasteners, such as lock bolts (not shown).
[0033] If differential expansion problems appear, for
example between bladed sectors, intermediate parts, that may
be deformable or not, may be inserted radially or
circumferentially into the assembly.
[0034] The advantages of the concept as in the invention
for producing turbomachine rectifiers are the following:
CA 02811069 2013-03-11
r
- reduced mass relative to the prior art, thanks to the use
of composites for the cases and possibly for the bladings;
- limited production cost, thanks to a smaller number of
parts and easy assembly;
- the static part of the booster (compressor) is more simply
and more cost-effectively repaired, the simple replacement
of a blade sector being much easier than in the case of
the most common current architectures (for example, welded
titanium assembly); and
- the production of finished parts without reworking after
leaving the mold.
