U.S. patent application number 14/012299 was filed with the patent office on 2014-03-06 for gas turbine fan casing having a belt for fastening equipment.
This patent application is currently assigned to SNECMA. The applicant listed for this patent is SNECMA. Invention is credited to Thierry Godon, Julien SCHNEIDER.
Application Number | 20140064957 14/012299 |
Document ID | / |
Family ID | 47003135 |
Filed Date | 2014-03-06 |
United States Patent
Application |
20140064957 |
Kind Code |
A1 |
SCHNEIDER; Julien ; et
al. |
March 6, 2014 |
GAS TURBINE FAN CASING HAVING A BELT FOR FASTENING EQUIPMENT
Abstract
The invention relates to a gas turbine fan casing (10)
comprising an annular casing wall (12) centered on a longitudinal
axis (X-X) of the casing and at least one fastening belt (100)
mounted on the periphery of the casing wall to fasten equipment on
the casing, each fastening belt comprising two distinct annular
flanges (102, 104) each having an L-shaped straight section, said
flanges being fastened to each other and maintained on the wall of
the casing by tightening of the inverted cone type.
Inventors: |
SCHNEIDER; Julien;
(Corbeil-Essonnes, FR) ; Godon; Thierry; (Sevran,
FR) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SNECMA |
Paris |
|
FR |
|
|
Assignee: |
SNECMA
Paris
FR
|
Family ID: |
47003135 |
Appl. No.: |
14/012299 |
Filed: |
August 28, 2013 |
Current U.S.
Class: |
415/214.1 |
Current CPC
Class: |
F02C 7/32 20130101; F01D
21/045 20130101; Y02T 50/672 20130101; F01D 25/243 20130101; F05D
2250/292 20130101; F05D 2240/90 20130101; Y02T 50/60 20130101 |
Class at
Publication: |
415/214.1 |
International
Class: |
F01D 25/24 20060101
F01D025/24 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 30, 2012 |
FR |
12 58091 |
Claims
1. A gas turbine fan casing comprising an annular casing wall
centered on a longitudinal axis of the casing and at least one
fastening belt mounted on a periphery of the casing wall to fasten
equipment on the casing, and wherein, each fastening belt comprises
two distinct annular flanges each having an L-shaped straight
section, said flanges being fastened to each other and maintained
on the wall of the casing by an inverted cone tightening
mechanism.
2. The casing according to claim 1, wherein two flanges of a same
fastening belt are maintained by tightening on a crown of the wall
of the casing having two opposite planes that are inclined relative
to the longitudinal axis of the casing.
3. The casing according to claim 2, wherein each flange of a same
fastening belt has a contact leg bearing on one of the inclined
planes of the crown and a tightening leg designed to be assembled
to the tightening leg of the other flange of said belt.
4. The casing according to claim 3, wherein the planes of the crown
are inclined in an open cone toward an inside of the wall of the
casing, the casing further comprising tightening devices to
assemble the tightening legs of two flanges of the fastening belt
to each other by bringing said tightening legs closer to each other
so as to ensure tightening thereof on the wall of the casing.
5. The casing according to claim 3, wherein the planes of the crown
are inclined in an open cone toward the outside of the wall of the
casing, the casing further comprising tightening devices to
assemble the tightening legs of the two flanges of the fastening
belt to each other by separating them from one another so as to
ensure tightening thereof on the wall of the casing.
6. The casing according to claim 4, wherein the tightening devices
comprise screw/nut systems.
7. The casing according to claim 1, comprising a plurality of
fastening belts axially spaced apart from each other.
8. The casing according to claim 7, wherein at least some of the
fastening belts are assembled to each other.
9. The casing according to claim 1, wherein the casing wall is made
from composite material with a fibrous reinforcement densified by a
matrix.
10. An aeronautic gas turbine engine having a fan casing according
to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to the general field of gas
turbine casings, and more particularly gas turbine fan casings for
aeronautic engines.
[0002] In a gas turbine aeronautic engine, the casing is made up of
a part forming an air intake sleeve, the function of which is to
define the air intake tunnel in the engine, and a part forming the
fan casing.
[0003] The fan casing in particular serves to retain debris, such
as ingested objects or damaged blade fragments, projected by
centrifugation, so as to prevent them from passing through the
casing and reaching other parts of the aircraft. The fan casing
also supports a certain number of pieces of equipment or
compartments of the engine, for example such as the hoses conveying
deicing fluid or the logic controller of the engine.
[0004] Commonly, a fan casing is made up of a metal wall defining
the intake tunnel. Between the ends of said wall, circumferential
structural reinforcing webs are added, said webs also being able to
serve to support equipment of the engine.
[0005] Furthermore, it has been proposed to make the fan casing
from a composite material of the fiber/resin type through the
production of a fibrous preform, impregnation with a resin, and
molding to obtain a desired shape directly. In fact, compared to
metal, the composite makes it possible to obtain significant mass
savings.
[0006] However, the use of the composite material to produce a fan
casing poses the problem of fastening the equipment of the engine
on the casing. In particular, the solution consisting of gluing
annular flanges on the wall of the casing to fasten the equipment
thereto is not fully satisfactory. In fact, the certification of
the gluing of parts that perform a structural function (namely the
fastening flanges) is extremely complex to obtain. Likewise, the
solution consisting of bolting the fastening flanges on the wall of
the casing is not satisfactory, since it requires piercing the
composite structure of the casing with all of the drawbacks that
that entails (discontinuity of the fibers, weakening of the
structure, concentration of stresses at the piercings, etc.).
[0007] Also known from document WO 2009/147307 is a solution
consisting of attaching a belt forming a gripping collar gripping
the casing on the outer periphery of the casing. This solution does
not have the aforementioned drawbacks. However, this principle of
fastening by strapping requires a closing point for the belt which,
in case of breakage, leaves the belt free with all of the ensuing
consequences.
SUBJECT-MATTER AND BRIEF DESCRIPTION OF THE INVENTION
[0008] The present invention therefore primarily aims to obviate
such drawbacks by proposing a solution for fastening equipment on a
fan casing, in particular made from a composite material, that does
not require gluing, piercing or using single fastening points.
[0009] This aim is achieved owing to a gas turbine fan casing
comprising an annular casing wall centered on a longitudinal axis
of the casing and at least one fastening belt mounted on the
periphery of the casing wall to fasten equipment on the casing, and
wherein, according to the invention, each fastening belt comprises
two distinct annular flanges each having an L-shaped straight
section, said flanges being fastened to each other and maintained
on the wall of the casing by tightening of the inverted cone
type.
[0010] The fastening belt is mounted on the casing wall by
tightening of the inverted cone type. This type of tightening
consists of strapping the belt on the casing by conical rubbing of
its flanges on the casing wall. Thus, the maintenance of the belt
on the casing wall is done without using gluing or piercing of the
wall of the casing. Likewise, the belt can completely cover the
circumference of the casing wall without needing to use a single
closing point of the belt, which avoids the problems related to the
rupture of such a point. Lastly, the maintenance of such a
fastening belt is facilitated as a result.
[0011] Preferably, the two flanges of a same fastening belt are
maintained by tightening on a crown of the wall of the casing
having two opposite planes that are inclined relative to the
longitudinal axis of the casing.
[0012] Also preferably, each flange of a same fastening belt has a
contact leg bearing on one of the inclined planes of the crown and
a tightening leg designed to be assembled to the tightening leg of
the other flange of said belt.
[0013] The planes of the crown may be inclined in an open cone
toward the inside of the wall of the casing, the casing further
comprising tightening means to assemble the tightening legs of two
flanges of the fastening belt to each other by bringing them closer
to each other so as to ensure tightening thereof on the wall of the
casing.
[0014] Alternatively, the planes of the crown may be inclined in an
open cone toward the outside of the wall of the casing, the casing
further comprising tightening means to assemble the tightening legs
of the two flanges of the fastening belt to each other by
separating them from one another so as to ensure tightening thereof
on the wall of the casing.
[0015] The tightening means of these two embodiments may comprise
screw/nut systems.
[0016] The casing may comprise a plurality of fastening belts
axially spaced apart from each other. At least some of these
fastening belts can be assembled to each other to form an extremely
high-performance fastening element (this element may for example
serve to ensure fastening of the engine on the wing of the
aircraft).
[0017] Also preferably, the casing wall is made from composite
material with a fibrous reinforcement densified by a matrix.
[0018] The invention also relates to an aeronautic gas turbine
engine having a fan casing as previously defined.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Other features and advantages of the present invention will
emerge from the description provided below, in reference to the
appended drawings which illustrate one non-limiting example
embodiment thereof. In the figures:
[0020] FIG. 1 is a very diagrammatic view of an aeronautic engine
gas turbine;
[0021] FIG. 2 is a partial axial cross-sectional view showing a
fastening belt assembled on the fan casing for a gas turbine like
that of FIG. 1;
[0022] FIG. 3 is an enlarged and exploded view of the fastening
belt of FIG. 2;
[0023] FIG. 4 is a view of a fastening belt for a fan casing
according to another embodiment of the invention; and
[0024] FIG. 5 illustrates still another embodiment of the fan
casing according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0025] The invention will be described hereafter in the context of
its application to the manufacture of a fan casing for an
aeronautic engine with a gas turbine.
[0026] Such an engine, as very diagrammatically shown in FIG. 1,
comprises, from upstream to downstream in the gas flow direction, a
fan 1 positioned at the input of the engine, a compressor 2, a
combustion chamber 3, a high-pressure (HP) turbine 4 and a
low-pressure (LP) turbine 5. The HP and LP turbines are
respectively coupled to the compressor and the fan by respective
coaxial shafts and are centered on a longitudinal axis X-X of the
engine.
[0027] The engine is housed inside a casing comprising several
parts corresponding to different elements of the engine. Thus, the
fan 1 is surrounded by a fan casing 10.
[0028] FIG. 2 shows a fan casing profile 10 made from a composite
material according to one embodiment of the invention. The casing
10 comprises an annular wall 12 centered on the longitudinal axis
X-X of the engine and whereof the inner surface 12a defines the air
intake tunnel. The latter may be provided with an abradable coating
layer (not shown) at the trajectory of the blade apices of the fan,
a plate 14 being partially shown very diagrammatically. An acoustic
treatment coating (not shown) may furthermore be positioned on the
inner surface of the casing, in particular upstream from the
abradable coating.
[0029] The casing 10 may be provided with outer flanges 16, 18 at
the upstream and downstream ends of the annular wall 12 so as to
allow it to be mounted and connected with other elements.
[0030] Preferably, the casing 10 is made from a composite material
with a fibrous reinforcement densified by a matrix. The
reinforcement is for example made from carbon, glass, aramid or
ceramic fibers, and the matrix from polymer, for example epoxide,
bismaleimide or polyimide.
[0031] To that end, as indicated in document EP 1,961,923, the
fibrous reinforcement may be formed by winding a fibrous texture
made by three-dimensional weaving on a mandrel, the mandrel having
a profile corresponding to that of the casing to be produced.
[0032] Advantageously, the fibrous reinforcement constitutes a
complete tubular fibrous preform of the casing 10 forming a single
piece with a corresponding part of the annular wall and the
reinforcing parts corresponding to the outer flanges 16, 18.
[0033] The fan casing 10 also comprises at least one fastening belt
100, 100' that is mounted on the periphery of the casing wall 12 so
as to allow the equipment to be fastened on the casing.
[0034] According to the invention, each fastening belt 100, 100'
comprises two distinct annular flanges 102, 104 each having an
L-shaped straight section, said flanges being in opposition, fixed
to one another and maintained on the wall 12 of the casing 10 by
tightening of the inverted cone type. In the embodiment of FIGS. 2
and 3, the flanges 102, 104 are 360.degree. parts.
[0035] The two flanges 102, 104 of a same fastening belt 100, 100'
are more specifically maintained by tightening on a crown 106 of
the wall 12 of the casing, said crown 106 having two opposite
planes 108, 110 that are inclined relative to the longitudinal axis
X-X of the engine.
[0036] Thus, in the embodiment of FIGS. 2 and 3, the planes 108,
110 of the crown 106 are inclined so as to form a cone that is open
toward the inside of the wall of the casing. In longitudinal
cross-section, the crown 106 has a triangular shape whereof the
apex is oriented toward the outside of the casing.
[0037] Alternatively, in the embodiment of FIG. 4, the planes 108',
110' of the crown 106' are inclined so as to form a cone that is
open toward the outside of the wall of the casing. In longitudinal
cross-section, the crown 106' thus has a triangular shape whereof
the apex is oriented toward the inside of the casing.
[0038] Furthermore, each flange 102, 106 of a same fastening belt
100 has a contact leg 102a, 104a, respectively, that bears on one
of the inclined planes of the crown 106, 106' and a tightening leg
102b, 104b, respectively, which is designed to be assembled to the
tightening leg of the other flange of the fastening belt by
tightening means described later.
[0039] Furthermore, in light of the particular shape of the crown
106 of the embodiment of FIGS. 2 and 3, for each flange 102, 104 of
a same tightening belt, the contact and tightening legs form an
angle a of more than 90.degree. between them. Likewise, due to the
particular shape of the crown 106' of the embodiment of FIG. 4, the
contact and tightening legs of the flanges 102, 104 of a same
fastening belt of this embodiment form an angle .beta. of less than
90.degree. between them.
[0040] The casing further comprises tightening means for assembling
the tightening legs 102b, 104b of the two flanges 102, 104 of the
fastening belt 100, 100' to each other.
[0041] In the embodiment of FIGS. 2 and 3, these tightening means
assume the form of screws 112 on which nuts 114 are tightened, the
screws passing through the tightening legs 102b, 104b of the two
flanges 102, 104 in a direction substantially parallel to the
longitudinal axis X-X of the engine.
[0042] In this way, by tightening the nuts 114 against the
tightening legs 102, 104b of the two flanges, the latter will tend
to come closer to each other and "rise" on the respective inclined
planes 108, 110 of the crown 106 so as to ensure tightening of the
fastening belt 100 on the wall 12 of the casing.
[0043] In the embodiment of FIG. 4, the tightening means also
assume the form of screws 112 on which nuts 114 are tightened, the
screws passing through the tightening legs 102b, 104b of the two
flanges 102, 104 in a direction substantially parallel to the
longitudinal axis X-X.
[0044] The tightening means also comprise spring washers 116 that
are inserted between the tightening legs 102b, 104b of the two
flanges 102, 104. In this way, by tightening the nuts 114 against
the tightening legs 102, 104b of the two flanges, the latter will
tend to move away from each other (under the effect of the spring
washers 116) and to "rise" on the respective inclined planes 108',
110' of the crown 106' so as to ensure tightening of the fasting
belt 100 on the wall 12 of the casing.
[0045] It will be noted that the screws 112 used to tighten the
fastening belt on the wall of the casing may also serve to fasten
elements 118 of the pieces of equipment or engine compartments of
the engine.
[0046] The mounting of the fastening belt 100 of the embodiment of
FIGS. 2 and 3 is done as follows. The flanges thereof are brought
around the casing wall (the flange 102 from downstream and the
flange 104 from upstream) and moved axially toward one another
(casing of FIG. 3). The screws 112 are then inserted into their
respective tightening legs and the nuts 114 are tightened against
the latter to ensure maintenance of the fastening belt on the
casing.
[0047] For mounting of the fastening belt 100' of the embodiment of
FIG. 4, it is necessary for the two flanges 102, 104 each to be
made in two parts. For example, it is possible to consider that the
two parts of the same flange are assembled around the casing wall
with a bevel-shaped partial angular overlap.
[0048] A description will be provided of another embodiment of a
fan casing according to the invention with respect to FIG. 5.
[0049] In this embodiment, it is provided that the fan casing 10
bears three fastening bolts 100 axially spaced apart from each
other and connected to each other by their respective screws 112.
More specifically, the screws 112 serving to tighten the fastening
bolts 100 on the wall 12 of the casing are the same for all three
belts.
[0050] Such an assembly of several fastening belts to each other
makes it possible to form an extremely powerful fastening element,
the latter for example being able to serve to ensure fastening of
the engine on the wing of the aircraft.
[0051] We will now describe certain features shared by all of the
embodiments previously described.
[0052] The crowns 106, 106' on which the flanges of the fastening
belts 100, 100' are mounted can be obtained by locally varying the
thickness of the wall 12 of the casing during the manufacture
thereof. Thus, this overthickness may be obtained either by using
threads with a larger size at the overthickness to be created
during the weaving of the fibrous texture wound on the mandrel, or
by introducing an insert between the different layers of fibrous
texture wound on the mandrel. In the event the wall of the casing
is manufactured by stratification, the necessary overthickness will
be obtained by performing different windings.
[0053] It is possible to decrease the height of the flanges 102,
104 (or specifically the respective tightening legs 102b, 104b)
locally in the areas in which no fastening of equipment or engine
compartments of the engine is provided. Mass savings may thus be
expected.
[0054] The contact dimension between the contact legs 102a, 104a of
the flanges 102, 104 of the fastening belts and the inclined planes
of the crowns 106, 106' of the casing wall may vary between 1 mm
and several centimeters. However, in the case where the flanges are
made from a different material from that of the casing wall, it
will be necessary to be careful to account for the expansion
differences between these materials in particular to prevent an
increase in the diameter due to expansion of the flanges from
causing sliding on the crown.
* * * * *