RING ENVELOPE FOR AN AIRCRAFT TURBOMACHINE

Abstract

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 called respectively first housing (40), second housing (50) and third housing (60), the annular casing (30) further comprising an acoustic annular panel (70) which is mounted inside the second housing (50) and which is axially clamped between the first and third housings (40, 60), the acoustic panel (70) comprising a first axial end (70a) which is mounted on the axial end of the first housing (40) by a first mortise-and-tenon assembly (72), with a first spring-loaded metallic annular flange (80). Figure for the abbreviation: Figure 2

Description

Title of the invention: RING ENCLOSURE FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to an annular casing for an aircraft turbomachine, as well as to an aircraft turbomachine comprising such a casing. Technical background

[0002] The technical background includes in particular the document FR-A1-2 999 650.

[0003] An aircraft turbomachine generally comprises at least one compressor, an 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.

[0004] An airflow generally flows inside an annular envelope that defines a flow channel for this airflow. To reduce noise emissions, it is known to line the inside of this envelope with acoustic panels.

[0005] Fig. 1 shows, for example, an annular envelope 10 which extends around a fan propeller 6 to define a flow channel 8 of a main flow Fl which is intended to divide downstream of the fan into a primary airflow which enters the compressor, and into a secondary airflow which flows around the turbomachine engine.

[0006] The casing 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.

[0007] 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, which creates 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.

[0008] The invention proposes a simple, effective and economical solution, which makes it possible to solve all or part of the problems mentioned above. Summary of the invention

[0009] 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 called respectively first housing, second housing and third housing,

[0010] the first housing comprising at an axial end a first annular flange,

[0011] 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,

[0012] the third housing comprising an axial end capable of being fixed or connected to the second end of the second housing,

[0013] the annular casing further comprising an acoustic annular panel which is mounted inside the second casing and which is axially clamped between the first and third casings,

[0014] 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 type assembly, this first assembly comprising a first annular lip extending around the axis and carried by one of the elements chosen 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,

[0015] and in that a first annular metallic shim is mounted on the lip and in the groove, this first shim 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 tightening of the acoustic panel between the first and third housings.

[0016] A first aspect of the invention relates to 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.

[0017] Another aspect of the invention relates to the type of mounting of the acoustic panel on the first housing. This mounting is of the tenon-mortise type, that is to say by male-female engagement.

[0018] Another aspect concerns the use of a shim in this mortise and tenon joint. The shim has a dual function here. On the one hand, it protects the joint and limits the risk of wear on the lip and the groove due to friction between them. On the other hand, the shim has a function of spring and elastic return. It is therefore understood that compressing the panel between the first and third housings will cause elastic deformation through compression of the shim. Axial tightening of the panel is therefore unlikely to damage it.

[0019] The envelope according to the invention may comprise one or more of the following features, taken individually or in combination with each other: • 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; • the second part has a generally wavy shape; • 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; • 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; • 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; • a second annular metal sash is mounted on the second lip and in the second groove; • the second tinplate is incompressible and not elastically deformable; • the second shim has a U-shaped cross-section; • the second shim is entirely housed in the second groove; • the axial end of the third housing includes an annular flange suitable to be fixed against an annular flange at the second end of the second casing; • The axial end of the third housing comprises an annular tab oriented radially inwards and adapted to engage in an annular groove oriented radially outwards in the second end of the second housing, the tab having a frustoconical face adapted to cooperate with a complementary truncated conical face of the groove in order to axially stress the second casing towards the first casing when the leg is engaged in the groove; • 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 clamping of the acoustic panel between the first and third housings; • The acoustic panel is sectorized and formed of several panel sectors arranged circumferentially around the axis.

[0020] The present invention also relates to an aircraft turbomachine, comprising at least one casing as described above.

[0021] The invention further relates to a method for mounting an annular envelope as described above, comprising the following steps:

[0022] - the first and second housings are fixed together one after the other,

[0023] - the first shim is mounted in the first groove,

[0024] - the acoustic panel is moved axially towards the first housing until The first annular lip engages in the first groove and rests against the first shim.

[0025] The process may further comprise the following steps:

[0026] - the second shim is mounted in the second groove,

[0027] - the third housing is fixed or connected to the second housing so that the second lip The annular part engages in the second groove, and the panel is stressed axially against the first cladding to deform it elastically. Brief description of the figures

[0028] 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:

[0029] [Fig-1] [Fig.1] is a partial schematic axial cross-sectional view of one of aircraft turbomachine,

[0030] [Fig.2] [Fig.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,

[0031] [Fig.3] [Fig.3] is a larger-scale detail view of [Fig.2] and shows a first tinsel,

[0032] [Fig.4] [Fig.4] is a larger-scale detail view of [Fig.2] and shows a second tinsel,

[0033] [Fig. 5] [Fig. 5] is a larger-scale detail view of [Fig. 2] and shows a type of connection between two housings, and

[0034] [Fig.6] [Fig.6] is a view similar to that of [Fig.5] and shows another type of fixing between two housings. Detailed description of the invention

[0035] The [Fig. 1] has already been described in the preceding.

[0036] Fig. 2 to 6 illustrate a first embodiment of an annular envelope 30 and an aircraft turbomachine 32 comprising this envelope 30.

[0037] 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.

[0038] 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,

[0039] 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.

[0040] The flange 42 includes a radial support face 42a whose internal periphery is connected to an internal annular surface 40a of the first housing 40 ([Fig.3]).

[0041] The second housing 50 has at a first axial end, located on the side of the housing 40, here upstream, a second annular flange 52 suitable for being fixed against the first flange 42.

[0042] 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.

[0043] 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.

[0044] In the example shown, flange 52 has a radial dimension smaller than that of flange 42 and covers an outer periphery of the aforementioned face 42a. In other words, face 52a has a radial extent smaller than that of face 42a. The inner periphery of face 42a is thus left free by flange 52.

[0045] 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.

[0046] The third housing 60 has an axial end, here upstream, suitable for being fixed or connected to this second end of the second housing 50.

[0047] The internal surface 50a of the housing 50 can have a diameter greater 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.

[0048] The annular envelope 30 further comprises an acoustic annular panel 70 which is mounted inside the second casing 50 and which is axially clamped between the first and third casings 40, 60.

[0049] 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.

[0050] 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.

[0051] This assembly 72 is of the lip and groove type.

[0052] In the example shown, an annular lip 74 extends around the axis and is supported by the panel 70, and an annular groove 76 extends around the axis and is supported by the housing 40. Alternatively, the reverse is possible.

[0053] The lip 74 is configured to be engaged axially in the groove 76 by translation along the axis.

[0054] In the example shown, the groove 76 is formed on the inner periphery of the aforementioned face 42a.

[0055] A first metallic ring 80 is mounted on the lip 75 and in the groove 76, as can be seen more clearly in [Fig.3].

[0056] 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 housing 60, after axial clamping of the acoustic panel 70 between the first and third housings 40, 60.

[0057] In the example shown, the shim 80 comprises a first annular part 80a with a U-shaped cross-section which is mounted on the lip 74 and in the groove 76, and a second annular part 80b which is connected to the first part 80a and which is located outside the groove 76 and interposed between the first and second housings 40, 50. It is this second part 80b which is axially compressible and elastically deformable.

[0058] The second part 80b can have a general wavy shape giving it this elastic deformation capacity.

[0059] This second part 80b may include a first curved annular portion 80b 1 which is separated from the first housing 40 and which defines the side of the panel 70 an axial support zone Z of this panel 70. This zone is in fact a circular support line that extends around the axis.

[0060] This second part 80b can 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 80b 1.

[0061] The second part 80b can be connected to the first part 80a by its first portion 80b 1.

[0062] 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.

[0063] The second assembly 82 is of the lip and groove type.

[0064] In the example shown, an annular lip 84 extends around the axis and is carried by the second housing 50, and an annular groove 86 extends around the axis and is carried by the panel 70. Alternatively, the reverse is possible.

[0065] The lip 84 is configured to be engaged axially in the groove 86 by translation along the axis.

[0066] A second metallic ring 90 is preferably mounted on the lip 84 and in the groove 86, as can be seen more clearly in [Fig.4].

[0067] This second slender 90 can be non-compressible and non-elastically deformable unlike the first slender 80.

[0068] The second 90 flashing, for example, has a U-shaped cross-section.

[0069] The second shim 90 is preferably entirely housed in the groove 86.

[0070] Figures 5 and 6 show two possible variants for the connection between the second and third housings 50, 60.

[0071] In the embodiment of [Fig.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.

[0072] The leg 100 has a frustoconical face 100a, here upstream, adapted to cooperate 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.

[0073] In this configuration, the third casing 60 could be part of an opening hood, for example of a thrust reversal system.

[0074] In the variant of [Fig. 6], the axial end of the third housing 60 comprises an annular flange 110 adapted to be fixed against an annular flange 112 of the second end of the second casing 50. The flanges 110, 112 include passage holes for fasteners 114 of the screw-nut type or similar.

[0075] The second housing 50 thus includes a flange 52, 112 at each of its axial ends.

[0076] In both cases, it can be seen 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.

[0077] The acoustic panel 70 is preferably sectorized and formed of several panel sectors arranged circumferentially around the axis.

[0078] Similarly, the 80, 90 flashings could be sectorized and formed of several sectors arranged end to end.

[0079] The shim or each 80, 90 is preferably formed from a folded or stamped metal sheet.

[0080] The casing 30 according to the invention can be mounted as follows, in accordance with a mounting method according to the invention. The housings 40, 50 are fixed together by means of their flanges 42, 52 and the aforementioned fastening elements.

[0081] 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, 84 engage respectively in the grooves 76, 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.

[0082] The acoustic panel 70 is centered by means of the two assemblies 72, 82 and thus held radially. The compression of the cladding 80 ensures axial immobilization of the panel 70 and the elimination of 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), said annular casing (30) extending about an axis and comprising three coaxial annular housings (40, 50, 60) mounted respectively one after the other, and respectively called first housing (40), second housing (50) and third housing (60), the first housing (40) comprising at an axial end a first annular flange (42), the second housing (50) comprising at a first axial end a second annular flange (52) adapted to be fixed against the first flange (42), the second housing (50) comprising a second axial end opposite said first end, the third housing (60) comprising 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) mounted inside the second housing (50) and axially clamped between the first and third housings (40, 60), characterized in that the acoustic panel (70) comprises a first axial end (70a) mounted on the axial end of the first housing (40) by a first mortise-and-tenon joint (72), this first joint (72) comprising 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 axially engaged in the groove (76) by translation along the axis, and in that a first metallic annular shim (80) is mounted on the lip (74) and in the groove (76),this first shim (80) 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 housing (60), after axial clamping of the acoustic panel (70) between the first and third housings (40, 60).

2. Annular envelope (30) according to claim 1, wherein the first shim (80) comprises a first annular portion (80a) a U-shaped 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 housings (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 (80b 1) 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 with the first housing (40), the second part (80b2) being connected to the first part (80b 1) by its first portion (80b 1).

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, wherein the second tinplate (90) is entirely housed in the second groove (86).

11. Annular casing (30) according to any one of claims 1 to 10, wherein the axial end of the third casing (60) comprises an annular flange (110) suitable for being fixed against an annular flange (112) of the second end of the second casing (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 in 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 enclosure (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 of mounting an annular enclosure (30) according to any one of claims 1 to 14, wherein it comprises the following steps: - the first and second housings (40, 50) are fixed together one after the other, - the first cladding (80) is mounted in the first groove (76), - the acoustic panel (70) is moved axially towards the first housing (40) until the first annular lip (74) engages in the first groove (76) and bears against the first cladding (80).

17. 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 cladding (90) is mounted in the second groove (86), - the third housing (60) is fixed or connected to the second housing (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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