Annular housing for an aircraft turbine engine

Abstract

The invention relates to an annular housing (30) for an aircraft turbine engine (32), the annular housing (30) extending about an axis and comprising three coaxial annular casings (40, 50, 60) which are mounted respectively one after the other and referred to as the first casing (40), second casing (50) and third casing (60) respectively, the annular housing (30) further comprising an annular acoustic panel (70) which is mounted inside the second casing (50) and is axially clamped between the first and third casings (40, 60), the acoustic panel (70) comprising a first axial end (70a) which is mounted on the axial end of the first casing (40) by means of a first mortise and tenon joint (72), with a first metal annular shim (80) having a spring function.

Description

[0001] DESCRIPTION

[0002] TITLE: RING ENVELOPE FOR AN AIRCRAFT TURBOMACHINE

[0003] Technical field of the invention

[0004] The present invention relates to an annular casing for an aircraft turbomachine, as well as an aircraft turbomachine comprising such a casing.

[0005] Technical background

[0006] The technical background includes, in particular, document FR-A1 - 2 999 650, GB-A-2 407 344, US-B2-9,611 ,863 and FR-A1 -3 024 753.

[0007] An aircraft turbomachine typically comprises at least one compressor, one annular combustion chamber, and at least one turbine. The airflow entering the compressor is compressed, then mixed with fuel and burned in the combustion chamber. The combustion gases are then expanded in the turbine, which drives the turbine rotor, which in turn drives the compressor rotor.

[0008] An airflow typically flows inside an annular enclosure that defines a flow channel. To reduce noise emissions, it is common practice to line the inside of this enclosure with acoustic panels.

[0009] Figure 1 shows, for example, an annular envelope 10 which extends around a blower propeller 6 to define a flow channel 8 of a main flow F1 which is intended to split downstream of the blower into a primary airflow which enters the compressor, and a secondary airflow which flows around the turbomachine engine.

[0010] The enclosure 10 comprises coaxial annular housings 12, 14 which are mounted one behind the other by clamping and within which are arranged acoustic annular panels 16, 18. Each panel 16, 18 is fixed to at least one of the housings 12, 14 by a system 20 of bushings and screws. Each system 20 comprises a bushing 22 which is engaged in an opening in the panel 16, 18 and which passes through its entire thickness, and a screw 24 which passes through the bushing 20 as well as through a hole 26 in the housing 12, 14 to be screwed into a nut 28.

[0011] This type of assembly has drawbacks. The assembly time for a panel 16, 18 is relatively long. The fastening systems 20 are relatively bulky and pass through the panels 16, 18, creating discontinuities in the acoustic treatment of the housings. Gaps may exist upstream and downstream of the panels 16, 18, which can generate areas without acoustic treatment.

[0012] The invention offers a simple, effective and economical solution, which makes it possible to solve all or part of the problems mentioned above.

[0013] Summary of the invention

[0014] The invention relates to an annular casing for an aircraft turbomachine, this annular casing extending around an axis and comprising three coaxial annular housings mounted respectively one after the other, and respectively called first housing, second housing and third housing, the first housing comprising at an axial end a first annular flange, the second housing comprising at a first axial end a second annular flange adapted to be fixed against the first flange, the second housing comprising a second axial end opposite said first end, the third housing comprising an axial end adapted to be fixed or connected to the second end of the second housing, the annular casing further comprising an acoustic annular panel which is mounted inside the second housing and which is axially clamped between the first and third housings,characterized in that the acoustic panel comprises a first axial end which is mounted on the axial end of the first housing by a first tenon-mortise assembly, this first assembly comprising a first annular lip extending around the axis and carried by one of the elements selected from the panel and the first housing, and a first annular groove extending around the axis and carried by the other of said elements, the annular lip being configured to be engaged axially in the groove by translation along the axis, and in that a first annular metal plate is mounted on the lip and in the groove, this first plate being axially compressible and elastically deformable so as to exert an elastic restoring force in the axial direction on the acoustic panel, directed towards the third housing, after axial clamping of the acoustic panel between the first and third housings.

[0015] A first aspect of the invention concerns the fact that the acoustic panel is axially clamped between the first and third housings, which limits the risk of axial play around the panel. Advantageously, this axial clamping results from the fixing or connection of the third housing to the second housing.

[0016] Another aspect of the invention concerns the type of mounting of the acoustic panel on the first casing. This mounting is of the tenon-mortise type, that is to say by male-female engagement.

[0017] Another aspect concerns the use of a shim in this mortise and tenon joint. The shim serves a dual purpose. Firstly, it protects the joint and reduces the risk of wear on the lip and groove caused by friction between them. Secondly, the shim acts as a spring and provides elastic return. Therefore, compressing the panel between the first and third brackets will cause elastic deformation through compression of the shim. Axial clamping of the panel will thus not damage it.

[0018] The envelope according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0019] - the first shim comprises a first annular part with a U-shaped cross-section which is mounted on the lip and in the groove, and a second annular part which is connected to the first part and which is located outside the groove and interposed between the first and second casings, this second part being axially compressible and elastically deformable;

[0020] - the second part has a generally wavy shape;

[0021] - the second part comprises a first curved annular portion set away from the first casing and defining a support area for the panel, and a second curved annular portion in sliding contact on the first casing, the second part being connected to the first part by its first portion;

[0022] - the acoustic panel includes a second axial end, opposite said first end, which is mounted on the second axial end of the second casing by a second tenon-mortise type assembly;

[0023] - the second assembly includes a second annular lip extending around the axis and carried by one of the elements chosen from the panel and the second casing, and a second annular groove extending around the axis and carried by the other of said elements, the second annular lip being configured to be engaged axially in the second groove by translation along the axis;

[0024] - a second annular metal sash is mounted on the second lip and in the second groove;

[0025] - the second tinplate is incompressible and not elastically deformable;

[0026] - the second piece of shim has a U-shaped cross-section;

[0027] - the second shim is entirely housed in the second groove; - the axial end of the third housing includes an annular flange suitable for being fixed against an annular flange of the second end of the second housing;

[0028] - the axial end of the third housing includes an annular tab oriented radially inwards and adapted to be engaged in an annular groove oriented radially outwards of the second end of the second housing, the tab having a frustoconical face adapted to cooperate with a complementary frustoconical face of the groove in order to axially stress the second housing towards the first housing when the tab is engaged in the groove;

[0029] - the axial end of the third housing is in axial support on the acoustic panel and the fixing or linking of this axial end to the second end of the second housing ensures the axial tightening of the acoustic panel between the first and third housings;

[0030] - the acoustic panel is sectorized and formed of several panel sectors arranged circumferentially around the axis.

[0031] The present invention also relates to an aircraft turbomachine, comprising at least one casing as described above.

[0032] The invention further relates to a method for assembling an annular envelope as described above, comprising the following steps:

[0033] - The first and second crankcases are fixed together, one after the other.

[0034] - the first shim is mounted in the first groove,

[0035] - the acoustic panel is moved axially towards the first casing until the first annular lip engages in the first groove and rests on the first shim.

[0036] The process may also include the following steps:

[0037] - the second shim is mounted in the second groove,

[0038] - the third casing is fixed or connected to the second casing so that the second annular lip engages in the second groove, and the panel is stressed axially against the first cladding to deform it elastically.

[0039] Brief description of the figures

[0040] Other features and advantages will become apparent from the following description of a non-limiting embodiment of the invention with reference to the accompanying drawings in which:

[0041] [Fig. 1] Figure 1 is a partial schematic axial cross-sectional view of an aircraft turbomachine,

[0042] [Fig.2] Figure 2 is a partial schematic perspective and axial section view of an aircraft turbomachine, and shows an embodiment of an annular casing according to the invention,

[0043] [Fig. 3] Figure 3 is a larger-scale detail view of Figure 2 and shows a first tinsel,

[0044] [Fig. 4] Figure 4 is a larger-scale detail view of Figure 2 and shows a second tinsel,

[0045] [Fig. 5] Figure 5 is a larger-scale detail view of Figure 2 and shows a type of connection between two housings, and

[0046] [Fig.6] Figure 6 is a view similar to that of Figure 5 and shows another type of fixing between two housings.

[0047] Detailed description of the invention

[0048] Figure 1 has already been described above.

[0049] Figures 2 to 6 illustrate a first embodiment of an annular envelope 30 and an aircraft turbomachine 32 comprising this envelope 30.

[0050] The turbomachine 32 can be of any type, for example turbojet, turboprop, etc. It can for example be of the ducted or unducted propeller type.

[0051] The casing 30 extends around an axis (not visible) and comprises three coaxial annular housings 40, 50, 60 mounted respectively one after or behind the other along the axis. These housings are respectively called first housing 40 or upstream housing, second housing 50 or intermediate housing and third housing 60 or downstream housing.

[0052] The first housing 40 has at an axial end, here downstream, a first annular flange 42. In the example shown, the flange 42 extends radially outwards and includes an annular row of axially oriented orifices.

[0053] The flange 42 comprises a radial bearing face 42a whose inner periphery is connected to an internal annular surface 40a of the first housing 40 (Figure 3). The second housing 50 has at a first axial end, located on the upstream side of the housing 40, a second annular flange 52 adapted to be fixed against the first flange 42.

[0054] In the example shown, the flange 52 extends radially outwards and includes an annular row of axially oriented orifices 52b intended to be aligned with the orifices of the flange 42 for the passage of screw-nut or similar type fastening elements.

[0055] The flange 52 includes a radial support face 52a whose internal periphery is connected to an internal annular surface 50a of the second housing 50.

[0056] In the example shown, flange 52 has a smaller radial dimension than flange 42 and covers an outer periphery of the aforementioned face 42a. In other words, face 52a has a smaller radial extent than face 42a. The inner periphery of face 42a is thus left free by flange 52.

[0057] The second housing 50 has a second axial end opposite the flange 52, here downstream, which is therefore located on the side of the third housing 60.

[0058] The third casing 60 has an axial end, here upstream, suitable for being fixed or connected to this second end of the second casing 50.

[0059] The internal surface 50a of the housing 50 may have a diameter larger than the diameters of the internal surfaces 40a, 60a of the housings 40, 60, as in the example shown, so that the housing 50 defines, between the housings 40, 60, an annular space E of larger diameter. The annular enclosure 30 further includes an acoustic annular panel 70 which is mounted inside the second housing 50 and is axially clamped between the first and third housings 40, 60.

[0060] The panel 70 can be mounted in the aforementioned space E so that the internal surface 70c of the panel 70 is aligned with the internal surfaces 40a, 60a of the housings 40, 60.

[0061] The acoustic panel 70 includes a first axial end 70a which is mounted on the axial end of the first housing 40 by a first tenon-mortise type assembly 72.

[0062] This assembly 72 is of the lip and groove type.

[0063] In the example shown, an annular lip 74 extends around the axis and is carried by the panel 70, and an annular groove 76 extends around the axis and is carried by the housing 40. Alternatively, the reverse is possible.

[0064] The lip 74 is configured to be engaged axially in the groove 76 by translation along the axis.

[0065] In the example shown, groove 76 is formed on the inner periphery of the aforementioned face 42a.

[0066] A first metallic ring 80 is mounted on the lip 75 and in the groove 76, as can be seen more clearly in figure 3.

[0067] This first shim 80 has the particularity of being axially compressible and elastically deformable so as to exert an elastic restoring force in the axial direction on the acoustic panel 70, directed towards the third casing 60, after axial tightening of the acoustic panel 70 between the first and third casings 40, 60.

[0068] In the example shown, the shim 80 comprises a first annular portion 80a with a U-shaped cross-section, mounted on the lip 74 and in the groove 76, and a second annular portion 80b connected to the first portion 80a, located outside the groove 76 and sandwiched between the first and second housings 40, 50. It is this second portion 80b that is axially compressible and elastically deformable. The second portion 80b may have a generally corrugated shape, giving it this elastic deformation capacity.

[0069] This second part 80b can include a first curved annular portion 80b1 which is separated from the first housing 40 and which defines on the side of the panel 70 an axial support zone Z of this panel 70. This zone is in fact a circular support line which extends around the axis.

[0070] This second part 80b may include a second curved annular portion 80b2 which is in sliding contact on the first housing 40 to allow elastic deformation of the first portion 80b1.

[0071] The second part 80b can be linked to the first part 80a by its first portion 80b1.

[0072] The acoustic panel 70 includes a second axial end 70b, opposite to the first end 70a and therefore located on the side of the third housing 60, which is mounted on the second axial end of the second housing 50 by a second tenon-mortise type assembly 82.

[0073] The second assembly 82 is of the lip and groove type.

[0074] In the example shown, an annular lip 84 extends around the axis and is supported by the second housing 50, and an annular groove 86 extends around the axis and is supported by the panel 70. Alternatively, the reverse is possible. The lip 84 is configured to be engaged axially in the groove 86 by translation along the axis.

[0075] A second metallic ring 90 is preferably mounted on the lip 84 and in the groove 86, as can be seen more clearly in figure 4.

[0076] This second 90 slender can be non-compressible and non-elastically deformable, unlike the first 80 slender.

[0077] The second 90 flashing, for example, has a U-shaped cross-section.

[0078] The second shim 90 is preferably entirely housed in groove 86.

[0079] Figures 5 and 6 show two possible variants for the connection between the second and third housings 50, 60. In the embodiment of Figure 5, the axial end of the third housing 60 includes an annular tab 100 oriented radially inwards and adapted to be engaged in an annular groove 102 oriented radially outwards of the second end of the second housing 50.

[0080] The leg 100 has a frustoconical face 100a, here upstream, capable of cooperating with a frustoconical face 102a complementary to the groove 102 in order to axially stress the second housing 50 towards the first housing 40 when the leg 100 is engaged in the groove 102.

[0081] In this configuration, the third 60 casing could be part of an opening hood, for example of a thrust reversal system.

[0082] In the variant of Figure 6, the axial end of the third housing 60 includes an annular flange 110 suitable for being fixed against an annular flange 112 of the second end of the second housing 50. The flanges 110, 112 include passage holes for fasteners 114 of the screw-nut type or similar.

[0083] The second housing 50 thus includes a flange 52, 112 at each of its axial ends.

[0084] In both cases, we observe that the axial end of the third housing 60 is in axial support on the axial end 70b of the acoustic panel 70, at point C of figures 5 and 6, and the fixing or linking of this axial end to the second end of the second housing 50 ensures the axial clamping of the acoustic panel 70 between the first and third housings 40, 60.

[0085] The acoustic panel 70 is preferably sectorized and formed of several panel sectors arranged circumferentially around the axis.

[0086] Similarly, the 80s and 90s flashing lights could be sectorized and formed from several sectors arranged end to end.

[0087] Each 80, 90 tinsel is preferably formed from a folded or stamped metal sheet.

[0088] The casing 30 according to the invention can be mounted as follows, in accordance with an assembly method according to the invention. The housings 40, 50 are fixed together by means of their flanges 42, 52 and the aforementioned fastening elements.

[0089] The shim 90 is mounted in the groove 86 of the panel 70, and the shim 80 is mounted in the groove 76 of the housing 40. The assembly formed by the panel 70 and the shim 80 is then mounted inside the housing 50 and moved axially towards the housing 40 until the lips 74 and 84 engage respectively in the grooves 76 and 86. The end 70a of the panel 70 then rests on the shim 80, and in particular its portion 80b. When the housing 60 is connected or fixed to the housing 50, it bears against the end 70b of the panel 70, which causes a deformation of the shim 80 by axial compression of its portion 80b.

[0090] The acoustic panel 70 is centered by the two assemblies 72 and 82 and thus held radially. The compression of the cladding 80 ensures axial immobilization of the panel 70 and eliminates axial play at the axial ends of the panel 70. The continuity of the grain is thus maintained.

Claims

DEMANDS 1. Annular casing (30) for an aircraft turbomachine (32), this annular casing (30) extending around an axis and comprising three coaxial annular housings (40, 50, 60) mounted one after the other, and respectively called first housing (40), second housing (50) and third housing (60), the first housing (40) having at one axial end a first annular flange (42), the second housing (50) having at one axial end a second annular flange (52) adapted to be fixed against the first flange (42), the second housing (50) having a second axial end opposite said first end, the third housing (60) having an axial end adapted to be fixed or connected to the second end of the second housing (50), the annular casing (30) further comprising an acoustic annular panel (70) which is mounted inside the second housing (50) and which is axially tightened between the first and third crankcases (40,60), characterized in that the acoustic panel (70) comprises a first axial end (70a) which is mounted on the axial end of the first housing (40) by a first mortise-and-tenon joint (72), this first joint (72) having a first annular lip (74) extending around the axis and carried by one of the elements selected from the panel (70) and the first housing (40), and a first annular groove (76) extending around the axis and carried by the other of said elements, the annular lip (74) being configured to be engaged axially in the groove (76) by translation along the axis, and in that a first annular metal flange (80) is mounted on the lip (74) and in the groove (76), this first flange (80) being axially compressible and elastically deformable so as to exert an elastic restoring force in the direction axial on the acoustic panel, (70), directed towards the third housing (60), after axial tightening of the acoustic panel (70) between the first and third housings (40, 60).

2. Annular envelope (30) according to claim 1, in which the first shim (80) comprises a first annular part (80a) with a U-shaped cross-section which is mounted on the lip (84) and in the groove (86), and a second annular part (80b) which is connected to the first part (80a) and which is located outside the groove (86) and interposed between the first and second casings (40, 50), this second part (80b) being axially compressible and elastically deformable.

3. Annular envelope (30) according to claim 2, wherein the second part (80b) has a generally corrugated shape.

4. Annular envelope (30) according to claim 2 or 3, wherein the second part (80b) comprises a first curved annular portion (80b1) set away from the first housing (40) and defining a support area for the panel (70), and a second curved annular portion (80b2) in sliding contact on the first housing (40), the second part (80b2) being connected to the first part (80b1) by its first portion (80b1).

5. Annular enclosure (30) according to any one of the preceding claims, wherein the acoustic panel (70) comprises a second axial end (70b), opposite said first end (70a), which is mounted on the second axial end of the second housing (50) by a second tenon-mortise type assembly (82).

6. Annular envelope (30) according to claim 5, in which the second assembly (82) comprises a second annular lip (84) extending around the axis and carried by one of the elements selected from the panel (70) and the second housing (50), and a second annular groove (86) extending around the axis and carried by the other of said elements, the second annular lip (84) being configured to be engaged axially in the second groove (86) by translation along the axis.

7. Annular envelope (30) according to claim 6, in which a second metallic annular shim (90) is mounted on the second lip (84) and in the second groove (86).

8. Annular envelope (30) according to claim 7, wherein the second slender (90) is non-compressible and non-elastically deformable.

9. Annular envelope (30) according to claim 7 or 8, wherein the second shim (90) has a U-shaped cross-section.

10. Annular envelope (30) according to any one of claims 7 to 9, in which the second tinplate (90) is entirely housed in the second groove (86).

11. Annular envelope (30) according to any one of claims 1 to 10, in which the axial end of the third housing (60) comprises an annular flange (110) suitable for being fixed against an annular flange (112) of the second end of the second housing (50).

12. Annular casing (30) according to any one of claims 1 to 10, wherein the axial end of the third casing (60) comprises an annular tab (100) oriented radially inwards and adapted to be engaged in an annular groove (102) oriented radially outwards of the second end of the second casing (60), the tab (100) having a frustoconical face (100a) adapted to cooperate with a frustoconical face (102a) complementary to the groove in order to axially stress the second casing (50) towards the first casing (40) when the tab (100) is engaged in the groove (102).

13. Annular envelope (30) according to any one of the preceding claims, wherein the axial end of the third housing (60) is axially supported on the acoustic panel (70) and the fixing or linking of this axial end to the second end of the second housing (50) ensures the axial clamping of the acoustic panel (70) between the first and third housings (40, 60).

14. Annular envelope (30) according to any one of the preceding claims, wherein the acoustic panel (70) is sectorized and formed of several panel sectors arranged circumferentially around the axis.

15. Aircraft turbomachine (32), comprising at least one casing (30) according to any one of the preceding claims.

16. A method for assembling an annular casing (30) according to any one of claims 1 to 14, wherein it comprises the following steps: - the first and second crankcases (40, 50) are fixed together one after the other, - the first shim (80) is mounted in the first groove (76), - the acoustic panel (70) is moved axially towards the first casing (40) until the first annular lip (74) engages in the first groove (76) and rests on the first cladding (80).

17. The method according to the preceding claim, the annular envelope (30) being as defined in any one of claims 7 to 10, the method further comprises the following steps: - the second shim (90) is mounted in the second groove (86), - the third casing (60) is fixed or connected to the second casing (50) so that the second annular lip (84) engages in the second groove (86), and the panel (70) is axially stressed against the first cladding (80) to deform it elastically.

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