U.S. patent application number 10/847860 was filed with the patent office on 2005-01-06 for hollow fan blade for turbine engine and method of manufacturing such a blade.
This patent application is currently assigned to SNECMA MOTEURS. Invention is credited to Despreaux, Jean-Louis, Franchet, Jean-michel, Leveque, Stephane, Lhomme, Daniel, Lorieux, Alain.
Application Number | 20050002786 10/847860 |
Document ID | / |
Family ID | 33104534 |
Filed Date | 2005-01-06 |
United States Patent
Application |
20050002786 |
Kind Code |
A1 |
Franchet, Jean-michel ; et
al. |
January 6, 2005 |
Hollow fan blade for turbine engine and method of manufacturing
such a blade
Abstract
The invention relates to a method of manufacturing a
single-piece hollow fan blade for turbine engines comprising a foot
(2) extended by a rotor blade (4) in a radial direction, the method
comprising the following stages: making via forging of a
single-piece fan blade (1) with a plurality of inserts; and
eliminating of the inserts so as to obtain a plurality of recesses
(16) in this blade. The invention also relates to such a blade (1)
fitted with a plurality of recesses (16) each extending
substantially and radially along a curved central line (18).
Inventors: |
Franchet, Jean-michel;
(Paris, FR) ; Lorieux, Alain; (Sannois, FR)
; Lhomme, Daniel; (Bessancourt, FR) ; Leveque,
Stephane; (Le Pecq, FR) ; Despreaux, Jean-Louis;
(Paris, FR) |
Correspondence
Address: |
OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
SNECMA MOTEURS
Paris
FR
|
Family ID: |
33104534 |
Appl. No.: |
10/847860 |
Filed: |
May 19, 2004 |
Current U.S.
Class: |
416/97R |
Current CPC
Class: |
B21K 3/04 20130101; F01D
5/18 20130101; F01D 5/14 20130101; B21J 5/00 20130101; F05D 2230/10
20130101; B23P 15/02 20130101 |
Class at
Publication: |
416/097.00R |
International
Class: |
B63H 001/14 |
Foreign Application Data
Date |
Code |
Application Number |
May 27, 2003 |
FR |
03 50187 |
Claims
1. Method of manufacturing a single-piece hollow fan blade for
turbine engines comprising a foot extended by a rotor blade in a
radial direction, characterised in that it comprises the following
stages: making via forging of a single-piece fan blade with a
plurality of inserts; and eliminating of inserts so as to obtain a
plurality of recesses in said blade.
2. Method of manufacturing set forth in claim 1, characterised in
that the production stage via forging of the single-piece blade
fitted with a plurality of inserts is carried out so that the
obtained recesses, following the elimination stage of the inserts,
each extend substantially and radially along a curved central
line.
3. Method of manufacturing set forth in claims 1 or 2,
characterised in that the production stage via forging of the
single-piece hollow fan blade fitted with a plurality of inserts is
carried out from a supply element equipped with said plurality of
inserts.
4. Method of manufacturing set forth in claim 1 or 2, characterised
in that the production stage via forging of the single-piece hollow
fan blade fitted with a plurality of inserts is carried out via the
implementing of the following stages: prior forging of a standard
supply element installing of said plurality of inserts in the
previously forged standard supply element forging of the previously
forged standard supply element and fitted with said plurality of
inserts, so as to obtain said single-piece fan blade fitted with a
plurality of inserts.
5. Method of manufacturing set forth in claim 1, characterised in
that the elimination stage of said inserts is carried out via
solvolysis of these inserts.
6. Method of manufacturing set forth in claim 1, characterised in
that each insert is made in a material taken from among the group
constituted of steels, minerals and composites.
7. Method of manufacturing set forth in claim 1, characterised in
that the initial form of said inserts is indifferently cylindrical
or non-cylindrical.
8. Method of manufacturing set forth in claim 1, characterised in
that the elimination stage of said inserts is followed by a
finishing stage of said blade.
9. Single-piece hollow fan blade for a turbine engine comprising a
foot extended by a rotor blade in a radial direction, said blade
being fitted with a plurality of recesses each extending
substantially and radially along a central line, characterised in
that each central line is a curved line.
10. Blade set forth in claim 9, characterised in that at least one
recess is made so as to radially and entirely pass through said
blade.
11. Blade set forth in claim 9, characterised in that at least one
recess is made so as to radially pass through said blade only
partially.
12. Blade set forth in claim 9, characterised in that at least one
recess is of non-constant section along said central line.
13. Blade set forth in claim 9, characterised in that it is made in
titanium or one of its alloys.
Description
TECHNICAL FIELD
[0001] The invention relates to the field of hollow blades for
turbine engine, and more particularly to those of hollow fan blades
with large chord.
[0002] Furthermore, the invention also relates to the method of
manufacturing such blades.
STATE OF THE PRIOR ART
[0003] In the prior art, fan blades with large chords for turbine
engines notably made their appearance in the embodiment of rotor
fan blades for double flow turbine engines.
[0004] Indeed, this type of blade has proved to be entirely
appropriate to satisfy the severe operating conditions, and further
integrates satisfactory mechanical characteristics as well as good
anti-vibration properties and shock resistant qualities from
foreign objects.
[0005] In order to obtain high speed at the end of the blade, a
mass reduction operation was rapidly proposed, by notably
presenting hollow blades.
[0006] In this regard, the making of hollow fan blades for turbine
engines firstly consisted in using techniques of hot-press moulding
of shell elements or diffusion bonding of two half blades type,
this diffusion bonding technique having been notably associated
with that of superplastic forming.
[0007] However, even though these known techniques made it possible
to make hollow fan blades with large chords, the implementing of
these remain relatively complex and expensive.
[0008] To overcome this inconvenience, the designing of a
single-piece hollow fan blade was proposed, in which recesses were
envisaged so as to reduce the overall mass.
[0009] Usually, the method of manufacturing of such a blade
consists in making a singe-piece blade via forging, then machining
a plurality of holes so as to obtain the desired recesses.
[0010] The document U.S. Pat. No. 5,407,326 discloses such a
method, in which the recesses are substantially made transversally
according to the thickness of the rotor blade. Once these recesses
have been made, it is necessary to blank them off using plugs, in
order to ensure the continuity of the upper and lower surfaces of
the blade.
[0011] To accomplish this, plugs are generally welded to the blade
through high energy beam, which renders the method of manufacturing
timely and expensive, these inconveniences being particularly
accentuated due to the large number of transversal recesses
envisaged to ensure a significant reduction in the overall mass of
the blade.
[0012] Thus, the making of recesses extending substantially
radially was proposed, as the document EP-A-0 924 381 notably
discloses. This type of recess is advantageous in that it usually
emerges around the foot of the blade, and that it does not modify
the upper and lower surfaces of this blade. Consequently, it is no
longer essential to carry out the fitting of a multitude of plugs
onto the established recesses, so that the method of manufacturing
is better optimised than that which incorporates the implementing
of transversal recesses.
[0013] Nevertheless, the standard machining operations to make the
radial holes do not allow to obtain recesses of any great length,
to the extent that the machined holes extend along a straight line
non-adapted to the curved shape of the blade. By way of
illustration and still in reference to the document EP-A-0 924 381,
the radial recesses principally extend around the foot of the
blade, but hardly prolong into the curved part of the rotor blade
in order to avoid emerging beyond it, and thus again require the
attaching of plugs ensuring the continuity of the upper and lower
surfaces.
[0014] Thus, the radial recesses encountered can only have short
lengths due to the major twisting encountered on such fan blades,
and consequently only participate in a largely insignificant manner
to the reduction of the overall mass of the single-piece blade.
OBJECT OF THE INVENTION
[0015] The purpose of the invention is therefore to propose, on one
hand a method of manufacturing a single-piece hollow fan blade for
turbine engines, and on the other hand such a single-piece hollow
fan blade for turbine engines the blade and the method of
manufacturing resolving at least partially the aforementioned
inconveniences regarding the embodiments of the prior art.
[0016] To accomplish this, the first object therefore of the
invention is a method of manufacturing a single-piece hollow fan
blade for turbine engines comprising a foot extended by a rotor
blade in a radial direction, the method comprising the following
stages:
[0017] making via forging of a single-piece fan blade with a
plurality of inserts; and
[0018] eliminating of the inserts so as to obtain a plurality of
recesses in this blade.
[0019] Advantageously, the recesses are not obtained via machining
operations, but through a simple elimination stage of the inserts
attached to the blade, these inserts having been preferably
deformed during the production stage via forging of the
single-piece blade.
[0020] In this manner, these recesses no longer necessarily extend
along a straight line as those obtained via standard machining, but
can on the contrary extend along a curved line.
[0021] This specificity is particularly advantageous in the
framework of the making of radial recesses, to the extent that the
latter can thus extend along a large radial length without emerging
around the upper and lower surfaces, by substantially following the
profile of the blade.
[0022] Thus, the length of the radial recesses is no longer
influenced by the curved form of the fan blade, and the reduction
in mass resulting from the presence of these recesses can thus be
significant.
[0023] Of course, this rapid and low cost method of manufacturing
can also be implemented for the making of recesses extending along
every direction through the blade, without diminishing the
framework of the invention.
[0024] Preferably, as indicated above, the production stage via
forging of the single-piece blade fitted with a plurality of
inserts is carried out so that the obtained recesses, following the
elimination stage of said inserts, each extend substantially and
radially along a central curved line.
[0025] In this regard, it is indicated that a digital simulation of
the forging operations makes it possible to easily envisage the
final positions of the recesses in the blade, as well as their
final form.
[0026] In a first preferred embodiment of the method of
manufacturing according to the invention, the production stage via
forging of the single-piece fan blade fitted with a plurality of
inserts is carried out from a supply element with a plurality of
inserts.
[0027] In such a configuration, the method is particularly simple
and rapid to implement.
[0028] In a second preferred embodiment of the method of
manufacturing according to the invention, the production stage via
forging of the single-piece fan blade fitted with a plurality of
inserts is carried out via the implementing of the following
operations:
[0029] prior forging of a standard supply element;
[0030] installing of the plurality of inserts in the previously
forged standard supply element;
[0031] forging of the previously forged standard supply element and
fitted with the plurality of inserts, so as to obtain the
single-piece fan blade fitted with a plurality of inserts.
[0032] In the two preferred embodiments of the method described
above, it can be envisaged that the elimination stage of the
inserts is carried out via solvolysis, these inserts preferably
being made in a material taken from the group composed of steels,
minerals and composites. In this regard, it is naturally indicated
that the solvolysis must be performed so that the agent(s) used
ensure the dissolution of the component material of the inserts,
without attacking the blade generally made in titanium or one of
its alloys.
[0033] As always in a preferable manner, the initial form of the
inserts is indifferently cylindrical or non-cylindrical, and of
circular or non-circular section.
[0034] Finally, in a continual manner, the method of manufacturing
is carried out so that the elimination stage of the inserts is
followed by a finishing stage of the blade.
[0035] Furthermore, the object of the invention is also a
single-piece hollow fan blade for a turbine engine comprising a
foot extended by a rotor in a radial direction, this blade being
fitted with a plurality of recesses each extending substantially
and radially along a central line, each central line being a curved
line.
[0036] As previously mentioned, the radial extension along curved
lines advantageously allows the recesses to have a considerable
length, to the extent that they can radially extend by following
the curved profile of the blade, without emerging onto the upper
and lower surfaces.
[0037] The reduction in mass resulting from the presence of these
radial recesses can thus be significant, particularly when the
blade is designed so that at least one recess is made so as to
radially and entirely pass through this fan blade.
[0038] Naturally, it is also possible that at least one recess is
made so as to radially pass through this blade only partially,
without dismissing the framework of the invention.
[0039] Finally, at least one recess of the blade is preferably of
non-constant section along the curved line.
[0040] Other advantages and characteristics of the invention will
appear in the non-restrictive detailed description below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] This description will be made in relation to the annexed
drawings among which;
[0042] FIG. 1 represents a perspective view of a first preferred
embodiment of the single-piece hollow fan blade according to the
invention;
[0043] FIGS. 2a to 2c diagrammatically illustrate different stages
of a first preferred embodiment of the method of manufacturing
according to the invention;
[0044] FIGS. 3a to 3e diagrammatically illustrate different stages
of a second preferred embodiment of the method of manufacturing
according to the invention;
[0045] FIG. 4 represents a perspective view of a second preferred
embodiment of the single-piece hollow fan blade according to the
invention;
[0046] FIG. 5 represents a perspective view of a third preferred
embodiment of the single-piece hollow fan blade according to the
invention; and
[0047] FIGS. 6 to 8 represent different forms that the inserts can
take following the production stage via forging of the single-piece
fan blade fitted with the plurality of inserts, during the
implementing of the method of manufacturing according to the
invention.
DETAILED PRESENTATION OF THE PREFERRED EMBODIMENTS
[0048] In reference to FIG. 1, we can notice a single-piece hollow
fan blade 1 for turbine engines (not represented), according to a
first preferred embodiment of the invention.
[0049] This single-piece hollow fan blade 1, of fan rotor blade
type with large chord, comprises a foot 2 extended by a rotor blade
4 in a radial direction.
[0050] The rotor blade 4, intended to be placed in the circulation
path of an airflow of the turbine engine, has two external surfaces
6 and 8, respectively called upper surface 6 and lower surface 8,
connected by a leading edge 10 and a trailing edge 12. Furthermore,
it has been noticed that the latter can have an intermediary part
14 between the foot 2 and the rotor 4, this part 14 also being
called "connection pole".
[0051] As can be seen in FIG. 1, the single-piece hollow fan blade
1, for example made in a titanium alloy, is fitted with a plurality
of recesses 16 each extending substantially radially according to a
central line 18 (only the three recesses 16 closest to the leading
edge 10 are represented entirely). In order to ensure a
considerable length for each of these recesses and without them
emerging around the upper and lower surfaces 6 and 8, each of the
central lines 18 is a curved line, capable of radially following
the profile of the blade.
[0052] In a first preferred embodiment, each recess 16 extends into
the blade 1 so as to pass entirely and radially through it, that
being by emerging on one hand around a lower end 20 of the foot 2,
and on the other hand around an upper end 22 of the rotor blade
4.
[0053] Furthermore, it can be envisaged that at least one recess 16
has a non-constant section along its central line 18, as
represented in FIG. 1. Indeed, in this preferred embodiment, the
section of the recesses 16 is greater around the foot 2 than around
the rotor blade 4. This capacity to vary the section of the
recesses 16 thus advantageously allows to adapt the volume of
withdrawn material to the local thickness of the blade, still so as
to obtain a maximum reduction in the overall mass of this blade 1,
whilst allowing it to maintain satisfactory mechanical properties.
Likewise, it is possible to envisage recesses of considerably
section around the centre of the blade 1, and recesses whose
sections progressively diminish in size as they get closer to the
leading edge 10 and the trailing edge 12.
[0054] In reference to FIGS. 4 and 5, we can see a single-piece
hollow fan blade 1 for turbine engines, respectively according to a
second preferred embodiment of the invention.
[0055] In these two preferred embodiments, recesses as always
extend radially in the single-piece hollow fan blade 1 along curved
central lines, but in a manner so as to only partially pass through
this said blade 1.
[0056] As can be seen in FIG. 4, blind recesses 116 extend along
curved central lines 118 so as to emerge at the upper end 22 of the
rotor blade 4, just as the recesses 16 of the first preferred
embodiment described above. However, these recesses 116 do not
extend as far as the foot 2, but only to a central section of the
blade 1, substantially placed half way up in the radial direction
of the latter.
[0057] Furthermore, as can be seen in FIG. 5, blind recesses 216
extend along curved central lines 218 so as to emerge at the lower
end 20 of the foot 2, just as the recesses 16 of the first
preferred embodiment described above. However, these recesses 216
do not extend as far as the upper end 22 of the rotor blade 4, but
only to a central section of the blade 1, substantially placed half
way up in the radial direction of the latter.
[0058] Of course, it is also possible to envisage a single-piece
fan blade 1 incorporating differently designed recesses such as
those presented in the description of the first, second and third
preferred embodiments, without dismissing the framework of the
invention. In this regard, it is indicated that the sought after
mechanical characteristics for the blade 1 influence the number of
these recesses, as well as their sections and lengths.
[0059] In reference to FIGS. 2a to 2c, different stages of a first
preferred embodiment of the method of manufacturing according to
the invention are represented diagrammatically.
[0060] FIG. 2a illustrates a supply element 24 equipped with a
plurality of inserts 26, this supply element 24 being intended to
undergo a forging stage consisting in one or several successive
operations, in order for it to have the form of a blade.
[0061] The inserts 26 integrated into the supply element 24,
indifferent to the initial cylindrical or non-cylindrical form, are
for example made using steels, composites or minerals, whereas the
supply element 24 is preferably made in a titanium alloy.
[0062] After having undergone this forging stage implemented
according to known techniques, the supply element 24 then has the
form of a blade 1 such as is represented in FIG. 2b, fitted with
inserts 26 placed in the same locations as those intended for the
recesses of this blade. In referring to this FIG. 2b, we can see
that the inserts 26, each of which was initially in the form of two
stacked coaxial cylindrical sections and of circular sections (FIG.
2a), have also been deformed during the forging stage.
[0063] Naturally, a digital simulation of the forging operations
easily allows to envisage the final positions of the inserts 26 in
the supply element 24 as well as the definitive shapes of these
said inserts, according to an initial specific configuration of the
supply element 24 fitted with inserts 26.
[0064] In this preferred embodiment, as represented in FIG. 2c,
corresponding to a transversal view of FIG. 2b along plane P, the
forging stage leads the inserts 26 to be fitted along a chard 30 of
the blade 1, and to have a substantially oval section of which the
two flattened ends are centred on this said chard 30.
[0065] Of course, as mentioned above, the final section of the
inserts 26 can vary according to the deformation mode employed, the
initial positioning of the inserts in the supply element 24, as
well as according to the initial shapes of these inserts 26 and of
the supply element 24.
[0066] By way of illustration, FIGS. 6 to 8 represent various
forms, other than those substantially oval, that can receive the
inserts 26 initially having cylindrical sections of circular
sections, following the forging stage of the supply element 24.
[0067] FIG. 6 shows an insert 26 fitted with a supply element 24
having undergone a major deformation during the forging stage. The
section of this insert 26 thus has the form of a band extending
substantially according along the chord 30 of the blade 1, and
whose central part if slightly thinner than the two end parts.
[0068] FIGS. 7 and 8 show inserts 26 equipping a supply element 24
having undergone a minor deformation during the forging stage. The
sections of these inserts 26, generally of oval shape similar to
the one represented in FIG. 2c, are such that respectively one or
the two flattened ends are substantially and progressively tapered
along the chord 30 of the blade 1.
[0069] Once this stage has been carried out, an elimination stage
of the inserts 26 is then performed, so that the latter give way to
recesses of the same shape.
[0070] This stage is preferably carried out via a solvolysis of the
inserts 26, for example by submerging the blade 1 fitted with these
inserts 26 into a bath of appropriate agent, that does not engender
a deterioration of the blade.
[0071] Thus, a single-piece hollow fan blade 1 is obtained such as
the one represented in FIG. 1, whose recesses 16 thus extend along
curved central lines 18 identical to the curved central lines 28
along which extend the inserts 26 through the supply element 24,
before the latter are eliminated.
[0072] Finally, this stage can thus be followed by a standard
finishing stage of the blade 1, intended to strictly give it the
desired airfoil profile.
[0073] In reference to FIGS. 3a to 3e, different stages of a second
preferred embodiment of the method of manufacturing according to
the invention are represented diagrammatically.
[0074] In this preferred embodiment, only the first production
stage via forging of a single-piece fan blade fitted with a
plurality of inserts differs in comparison to the method described
in the previous preferred embodiment.
[0075] Indeed, the implementing of a prior forging operation for a
standard supply element 32 is first carried out, such as the one
represented in FIG. 3a.
[0076] This standard supply element 32 is preferably made in a
titanium alloy, and has a substantially cylindrical form of
circular section.
[0077] The prior forging operation can thus consist in one or
several successive forging operations, preferably only one, whose
purpose is to obtain a previously forged supply element 32, such as
a preform with the approximate shape of a blade as shown in FIG.
3b.
[0078] Then, on this previously forged supply element 32, a
plurality of holes 34 intended to receive the inserts is made, as
can be seen in FIG. 3c. In this regard, it is specified that the
making of these holes 34 is performed using standard techniques
such as machining. Furthermore, it is obvious that the sought after
mechanical characteristics for the blade 1 define the number of
holes 34 to be envisaged, as well as their sections and lengths. By
way of illustration, the created holes 34 are cylindrical and of
constant section. Moreover, the sections of holes 34 can be very
large for those located near the centre of the preform, and of
diminishing size closer these holes 34 get to the edges of this
preform, as clearly illustrated in FIG. 3c. Naturally, the
feasibility criterion of holes 34 in the preform also arises in the
setting of the maximum dimensions that can be applied for these
holes 34.
[0079] Once the holes 34 have been made in a substantially radial
direction of the preform, the inserts 26 of complimentary form,
thus also cylindrical and of circular section, are effectively
places on the inside of the latter, as illustrated in FIGS. 3d and
3e.
[0080] Thus a forging operation can be carried out on the
previously forged standard supply element 32 and equipped with the
plurality of inserts 26, so as to obtain a single-piece blade
fitted with a plurality of inserts 26. The obtained blade is thus
similar to the one represented in FIG. 2b, except that the deformed
inserts 26 each have a substantially constant section along its
associated curved line 28, due to the initial cylindrical form of
these inserts 26.
[0081] As in the previous preferred embodiment, the final section
of the inserts 26 can vary according to the deformation modes
employed, the positioning of the inserts 26 in the previously
forged supply element 32, as well as according to the initial
shapes of these inserts 26 and of the previously forged supply
element 24.
[0082] Subsequently, the elimination and finishing stages are
substantially identical to those described in the first preferred
embodiment of the method according to the invention.
[0083] Of course, various modifications can be introduced by those
skilled in the art into the method of manufacturing the
single-piece hollow blade 1 which has just been described, solely
by way of non-restrictive illustration.
* * * * *