Aerodynamic turbine housing and method for manufacturing same

Abstract

The present invention relates to a casing (3) of an aircraft turbine, the casing comprising: - an annular shell (9) which extends around an axis A and is made of a composite material, the composite material comprising fibres woven and embedded in a resin; - an annular layer (4) of abradable material which extends around the axis A inside the shell and is obtained by spreading and polymerizing a slurry; and - a support plate (10) which extends around the axis A and is inserted between the shell and the abradable layer.

Description

Technical Field

[0001] The present invention relates to a casing for an aircraft turbine (in particular for a fan), and to a method for manufacturing said casing. Background Art

[0002] The prior art particularly includes the documents FR-A1-2 997 725, FR-A1-2 997 726, FR-A1-3 005 100, FR-A1-3 074 218, FR-A1-3 051 828, US-B2-8 202 041 and FR-A1-3 060 7438.

[0003] Figure 1 is a partial schematic view of a fan of an aircraft turbine.

[0004] In a conventional manner, a turbine includes, from upstream to downstream (i.e., along the flow direction of the air flow): a fan, one or more compressors, a combustion chamber, one or more turbines, and a nozzle for ejecting the combustion gases exiting one or more turbines.

[0005] The fan 1 includes an impeller 2 surrounded by a fan casing 3, and since the fan casing has the function of holding the blades in the case of blade breakage or debris entering the fan, the fan casing is also referred to as a retention casing.

[0006] As Figure 2 shown, the fan casing 3 generally includes an annular shroud 9 having a rotational axis A, and the annular shroud extends around the fan blades 2 of the turbine. This shroud includes annular connecting flanges 3', 3” at each of its axial ends. These flanges 3', 3” are used to attach the casing 3 to the annular wall of the nacelle of the turbine.

[0007] Figure 3 is a schematic cross-sectional view showing a fan casing 3 according to the prior art.

[0008] The fan casing 3 is connected upstream to an air inlet sleeve 5 and downstream to an intermediate casing shroud 6. The casing also carries an upstream acoustic panel 7 and a downstream acoustic panel 8. The fan casing 3 further includes an annular layer 4 of abradable material, which is located on the inner annular surface of the shroud and between the upstream panel 7 and the downstream panel 8.

[0009] In addition to the holding function, the fan casing 3 is also designed to:

[0010] - Ensure the continuity of the aerodynamic duct using the annular layer of abradable material;

[0011] - Ensure the mechanical continuity (forces and moments) between the air inlet sleeve 5 and the intermediate casing shroud 6;

[0012] - Achieve the connection between the implementation boards 7, 8 and layer 4;

[0013] - Achieve the attachment to known devices and the support brackets themselves;

[0014] - Comply with the regulations of fire and leakage;

[0015] - Achieve current continuity for lightning protection, etc.

[0016] As can be seen in the larger cross-sectional view in Figure 4 The wearable support plates 10 are inserted between the cladding 9 and layer 4. These plates 10 are generally formed of a sandwich structure that includes a skin layer 10b covering a honeycomb layer 10c (i.e., having open cells). The skin layer 10b extends between the cladding 9 on one side of the honeycomb layer 10c, and an adhesive layer 10a extends between the layer 4 on the other side of the honeycomb layer 10c.

[0017] The plates 10 are adhered to the inner surface of the cladding 9, and the wearable layer 4 is generally obtained by spreading and polymerizing a slurry composed of a mixture of pre-mixed components.

[0018] The layer 4 is formed, for example, of a two-component dense epoxy resin filled with glass microspheres. The wearable layer 4 is used to ensure a minimum clearance between the tips of the fan blades 2 and the housing 3. During the first rotation of the fan, these blades 2 wear the layer and adjust the clearance between the tips of the blades and the layer 4 in a manner optimized for a given engine. Thus, by adapting the trajectory of the layer to the respective clearances of the blades of each engine, the efficiency of the engine is ensured.

[0019] In the current technology, the wearable layer 4 has a relatively large thickness and can reach 8 mm. When mixing viscous components, special care must be taken to limit the porosity caused by mixing and degassing, and at the same time ensure good mixing of the two components. Once deposited and formed, the polymerization reaction can be ensured at room temperature or in an oven. Pores often appear after polymerization, and local repair is necessary.

[0020] Although the deposition method has been optimized to reduce the porosity in the wearable layer, due to the degassing of the material or the deposition method below the visible surface, some pores still remain.

[0021] For this reason, during installation, acceptance, or use testing, some engines may expose pores after running-in. In addition, since the material of the wearable layer has low cohesion, it is prone to local loss due to the pores and cracking below.

[0022] The present invention provides a simple, effective, and economical solution to at least some of the problems of the prior art. Summary of the Invention

[0023] According to a first embodiment, the present invention relates to an aircraft turbine casing, which comprises:

[0024] - an annular shroud that extends around axis A and is made of a composite material, the composite material comprising fibers woven and embedded in a resin,

[0025] - an annular layer of abradable material that extends around axis A within the shroud and is obtained by spreading and polymerizing a slurry, and

[0026] - a support plate that extends around axis A and is inserted between the shroud and the abradable layer,

[0027] characterized in that the layer is associated with at least one fiber reinforcement.

[0028] In order to solve problems such as low cohesion of the material, sensitivity to drawing, and cracking during use, the present application proposes to reinforce it with one or more fiber reinforcements to improve its cohesion.

[0029] The casing according to the present application may include one or more of the following features, which may be considered independently or in combination with each other:

[0030] - Reinforcing fibers (for example, with a length between 0.5 mm and 20 mm) are dispersed in the slurry and the abradable layer to solve the problem of porosity or large material loss (in addition to porosity). The idea is to add fiber reinforcements in the form of fibers (such as glass, aramid, or carbon) according to the influence on the material density during the process of mixing the components of the abradable layer; this strengthens the strength of the resin against tensile, compressive, and shear stresses in all directions;

[0031] - Reinforcing rings or fabrics are embedded in the abradable layer or inserted between the layer and the plate;

[0032] - The plates are separated from each other by gaps filled with the slurry, and at least some of the rings or fabrics cover these gaps; regarding the problem of cracking, fiber reinforcement tapes (these fiber reinforcement tapes may or may not be woven) can be used in the connection areas of these plates to prevent cracking of the abradable layer; for example, these tapes can be woven together with each other to facilitate their wetting through the abradable layer;

[0033] - A foam layer is inserted between the plate and the wearable layer; to overcome the problems of mechanical strength and porosity, it is also considered to replace most of the thickness of the wearable layer with a foam layer (for example, by using an adhesive or bonding through the wearable layer on the plate); this alternative solution can reduce the amount of wearable slurry used, thereby promoting the exhaust of the material, which greatly reduces the number of pores; in addition, the foam can absorb the shear deformation in the connection area of these plates; in association with the fibers as described above, this foam also increases the cohesive strength of the material, the wettability with the substrate, reduces the number of pores and lowers the cost of the wearable track; the remaining wearable layer can ensure the wearability of the support, thus ensuring the clearance with the top of the blade.

[0034] The present invention also relates to an aircraft turbine, including a housing as described above, in particular a housing extending around the fan of the turbine.

[0035] The present invention also relates to a method for manufacturing the housing as described above, wherein the method includes the following steps:

[0036] - Bonding the plate to the inner annular surface of the shroud,

[0037] - Preparing a slurry and spreading the slurry on the inner annular surface (such as the plate) to form a wearable layer, which is associated with at least one fiber reinforcement.

[0038] The method may include one or more of the following features or steps, which can be considered independently or in combination with each other:

[0039] - Mixing reinforcing fibers into the slurry before spreading the slurry, or arranging a reinforcing ring or reinforcing fabric on the inner annular surface of the plate before spreading the slurry;

[0040] - The slurry is spread on the inner annular surface of a foam layer previously bonded to the inner annular surface of the plate;

[0041] - The slurry is spread in a plurality of sub-steps, each sub-step including: depositing the slurry in the shape of a ball on the inner annular surface, spreading the slurry on this surface to make its thickness uniform, the slurry extending on a predetermined angular segment of this surface, and then forming a chamfer at the edge of the slurry, so that the slurry deposited and spread on the adjacent angular segments can cover this chamfered edge.

[0042] According to a second embodiment, the present invention relates to an aircraft turbine housing, which includes:

[0043] - An annular shroud, which extends around axis A and is made of a composite material, and the composite material includes fibers woven and embedded in resin,

[0044] - An annular layer of abradable material, the annular layer of abradable material extending within the casing about axis A and obtained by spreading and polymerizing a slurry, and

[0045] - A support plate, the support plate extending about axis A and being inserted between the casing and the abradable layer,

[0046] characterized in that the abradable layer is deposited on the inner annular surface of a foam layer, the foam layer itself being deposited on the inner annular surface of the plate.

[0047] The casing according to the present application may include one or more of the following features, which may be considered independently of one another or in combination with one another:

[0048] - The thickness of the foam layer is between 1 mm and 7 mm, preferably between 3 mm and 5 mm;

[0049] - The sum of the thicknesses of the abradable layer and the foam layer is less than or equal to 10 mm, and preferably less than or equal to 8 mm;

[0050] - The foam layer is made of a thermoplastic material;

[0051] - The density of the foam layer is between 20 Kg / m 3 and 100 Kg / m 3 ;

[0052] - The abradable layer is associated with at least one fiber reinforcement selected from reinforcing fibers and reinforcing rings or fabrics;

[0053] - The plates are separated from one another by gaps, the gaps being filled with the slurry, and at least some of the rings or fabrics covering the gaps.

[0054] The features of two embodiments of the present invention can be combined together naturally.

[0055] The present invention also relates to an aircraft turbine including a casing as described above, in particular a casing extending around the fan of the turbine.

[0056] The present invention also relates to a method for manufacturing a casing as described above, wherein the method comprises the following steps:

[0057] - Bonding the plates to the inner annular surface of the casing,

[0058] - Bonding the foam layer to the inner annular surface of the plates, and

[0059] - Preparing the slurry and spreading the slurry on the inner annular surface of the foam layer.

[0060] The reinforcing fibers can be mixed into the slurry before the slurry is spread. Alternatively or additionally, a reinforcing ring or fabric can be arranged on the inner annular surface before the slurry is spread thereon.

[0061] According to a third embodiment, the present invention relates to a method for manufacturing an aircraft turbine housing, the housing comprising:

[0062] - an annular shroud that extends around an axis A and is made of a composite material comprising fibers woven and embedded in a resin,

[0063] - an annular layer of abradable material extending within the shroud, and

[0064] - a support plate that extends around axis A and is inserted between the shroud and the abradable layer,

[0065] characterized in that the method comprises the following steps:

[0066] a) preparing a slurry by mixing at least two components,

[0067] b) depositing the slurry onto the inner annular surface of the plate,

[0068] c) spreading the slurry by means of at least one roller that extends substantially parallel to axis A and is arranged to roll on guide rings disposed on both sides of the plate or the shroud and is coaxial with the guide rings so as to form an angular section of the abradable layer, the angular section extending around axis A by a predetermined angle,

[0069] d) forming a chamfer at the circumferential ends of the thus formed section,

[0070] e) repeating steps a) to d) until a plurality of consecutive angular sections of the abradable layer are formed and cover the entire inner surface of the plate, the sections formed in step e) each comprising a circumferential end that covers the chamfered circumferential end of a previously deposited section.

[0071] The method according to the invention allows the abradable layer to be formed as a plurality of consecutive sections, the edges of which adjacent to the circumferential ends are chamfered and cover each other. This way of forming the abradable layer can limit the appearance of pores and defects in the layer.

[0072] In a particular case of implementing the method, the method can reduce the time for manufacturing the housing by 80%, and in particular reduce the duration for finishing the housing at the end of the method by 50%.

[0073] The method according to the present application may include one or more of the steps or features described below, which can be considered independently of each other or in combination with each other:

[0074] - The paste is based on epoxy resin, and preferably, the paste is filled with, for example, glass microbeads;

[0075] - The mixing is carried out in step a) by incorporating the components into a vessel of a mixer, the vessel including at least one rotating mixing element along two non - parallel rotational axes;

[0076] - The rotating element rotates around the axis at a speed of 400 revolutions per minute to 1000 revolutions per minute, preferably 600 revolutions per minute to 900 revolutions per minute for a time of 50 seconds to 200 seconds, preferably 80 seconds to 120 seconds;

[0077] - The vessel includes a bottom that can be withdrawn, for example, by a piston, from the inside to the outside of the vessel to facilitate removal of the paste from the vessel;

[0078] - The mass of the paste deposited in step b) is between 400 g and 2600 g;

[0079] - The housing is positioned such that axis A is substantially horizontal during steps b) to e);

[0080] - During step c) or during each step c), the housing rotates around axis A;

[0081] - The paste is deposited in step b) in the shape of a string or a ball;

[0082] - The thickness of the wearable layer is between 3 mm and 10 mm, preferably between 5 mm and 8 mm.

[0083] - The method further includes step i) between steps b) and c) and / or between steps c) and d): scraping the paste or the section by a blade;

[0084] - During step c), a plastic film is inserted between the at least one roller and the paste;

[0085] - The at least one roller used in step c) has a non - cylindrical profiled shape;

[0086] - The guide rings in step c) are axially pulled towards each other and against the plate by an elastic band extending between the guide rings;

[0087] - The chamfer formed in step d) extends along the entire axial dimension of the section and is oriented at approximately 45° to the normal of the inner surface of the section;

[0088] - The method includes a final step g): finishing the inner surface of the wearable layer, during which the housing is positioned such that its axis A is substantially vertical;

[0089] - The method includes a preliminary step of bonding a plate to the inner annular surface of the casing. Description of the Drawings

[0090] Other features and advantages of the present invention will become apparent from the following detailed description, and the description is facilitated by reference to the accompanying drawings, in which:

[0091] Figure 1 previously discussed Figure 1 shows a partial cross-sectional view of a fan of an aircraft turbine according to the prior art;

[0092] Figure 2 previously discussed Figure 2 shows a perspective view of a fan casing according to the prior art;

[0093] Figure 3 Figure 3 shows a schematic cross-section of a fan casing according to the prior art;

[0094] Figure 4 Figure 4 is a schematic cross-sectional view of a casing according to the prior art;

[0095] Figure 5 Figure 5 is a schematic cross-sectional view of a casing according to the present invention;

[0096] Figure 6 Figure 6 is a schematic cross-sectional view of a casing according to the prior art and shows the propagation of a crack;

[0097] Figure 7 Figure 7 is a schematic cross-sectional view of a casing according to the present invention and shows the limitation of the propagation of a crack;

[0098] Figure 8 Figure 8 is a view similar to Figure 6 and shows an alternative embodiment or another embodiment of the present invention;

[0099] Figure 9 Figure 9 is a flowchart showing the steps of a manufacturing method according to the present invention;

[0100] Figure 10 Figure 10 is a partial schematic cross-sectional view of an aircraft turbine casing;

[0101] Figure 11 Figure 11 ​​​​​​​​​​​​​​​​​​​​Schematic diagram of a component mixer for preparing a slurry;

[0102] Figure 12 Figure 12 In a to e are schematic diagrams of the housing and of an operator spreading a slurry on the housing to form a wear-resistant layer;

[0103] Figure 13 Figure 13 Schematic cross-sectional view of the spread wear-resistant layer;

[0104] Figure 14 Figure 14 Schematic diagram of a device for manufacturing a turbine housing;

[0105] Figure 15 Figure 15 is Figure 14 An enlarged schematic diagram of a part of the device in, and shows the steps of a manufacturing method according to the invention;

[0106] Figure 16 Figure 16 is Figure 14 An enlarged schematic diagram of a part of the device in, and shows further steps of a manufacturing method according to the invention;

[0107] Figure 17 Figure 17 is Figure 14 An enlarged schematic diagram of a part of the device in, and shows another step in a manufacturing method according to the invention. Detailed description

[0108] In the following description, the invention is applied to a fan housing 3. However, the invention is not limited to this type of housing and can be applied to other housings of turbines.

[0109] The housing 3 to which the method according to the invention is applied has a generally annular shape about an axis A. The housing 3 comprises:

[0110] - an annular cladding 9 which extends about the axis A and is made of a composite material comprising fibres woven and embedded in a resin, and

[0111] - an annular layer 4 of wear-resistant material arranged within the cladding 9.

[0112] As described above, the support plate 10 is inserted between the layer 4 and the cladding 9 and has a sandwich structure. Specifically, the support plate comprises a honeycomb layer of the honeycomb type which comprises open cells, rather than closed cells, or comprises units such as foam.

[0113] ​​​​​​​​​​​​To avoid the problems discussed above, layer 4 can be associated with at least one fiber reinforcement, which can be one or more types selected from, for example, fibers, laps, or fabrics. Fabrics are formed from fibers woven together, rather than laps formed from non-woven fibers.

[0114] In Figure 5 the example shown, reinforcing fibers 12 (for example having a length between 0.5 mm and 20 mm) are dispersed in the wearable layer 4. The reinforcing fibers include glass, aramid, or carbon fibers.

[0115] In Figure 7 the example shown, reinforcing laps or fabrics 14 are embedded in the wearable layer 4 or inserted between layer 4 and the plate 10. The laps or fabrics 14 can be used in combination with the fibers 12 mixed with the wearable paste.

[0116] In the case shown, these plates 10 are separated from each other by a gap J, which is filled with the paste of the layer, and at least some of the laps or fabrics 14 cover these gaps. This prevents cracks 16 that would appear in these gaps J from spreading to the free surface 4b of the wearable layer 4 ( Figure 6 and Figure 7 ).

[0117] Figure 5 and Figure 7 the fiber reinforcements of can be used alone or in combination with a foam layer 18 as shown in Figure 8 . This layer 18 is inserted between the plate 10 and the wearable layer 4 and provides a number of advantages. In particular, it enables the thickness of layer 4 to be reduced, thereby reducing the amount of material of the paste to be spread to manufacture the layer. It also reduces the risk of cracking and problems associated with using a thick layer 4.

[0118] Alternatively, according to a second embodiment of the invention, the foam layer 18 can be used in the absence of fiber reinforcements in the wearable layer 4.

[0119] The thickness of the foam layer 18 is, for example, between 1 mm and 7 mm, preferably between 3 mm and 5 mm. Preferably, the sum of the thicknesses of the wearable layer 4 and the foam layer 18 is less than or equal to 10 mm, and preferably less than or equal to 8 mm.

[0120] The foam layer 18 is made of a thermoplastic material, for example. The density of the foam layer can be between 20 Kg / m 3 and 100 Kg / m 3 ;

[0121] The housing 3 according to the invention can be manufactured as follows:

[0122] - Bond the plate 10 to the inner annular surface of the cladding 9,

[0123] - Prepare a slurry and spread the slurry on the inner annular surface (e.g., the inner annular surface of plate 10), and this layer is associated with at least one fiber reinforcement.

[0124] In Figure 5 In the illustrated embodiment, the reinforcing fiber 12 is mixed into the slurry before the slurry is spread.

[0125] In Figure 7 In the illustrated embodiment, before spreading the slurry, the reinforcing ring or fabric 14 is arranged on the inner annular surface of plate 10.

[0126] Finally, in Figure 8 In an alternative or second embodiment of the present invention in

[0127] Figure 9 is a flowchart or block diagram showing the steps of a method for manufacturing an aircraft turbine housing according to the present invention.

[0128] As discussed above and as Figure 10 shown, the housing includes:

[0129] - An annular shroud 9 that extends around an axis A (not shown) and is made of a composite material that includes fibers woven and embedded in a resin,

[0130] - An annular layer 4 of wear-resistant material that extends within the shroud, and

[0131] - A support plate 10 that extends around the axis A and is inserted between the shroud 9 and the wear-resistant layer 4.

[0132] The special feature of the housing 3 is that its wear-resistant layer 4 is formed by a plurality of angular segments 4a that are arranged one by one in circumferential end-to-end contact (around the axis A).

[0133] Figure 9 The method according to the present invention in

[0134] includes a plurality of steps, some of which are optional. Specifically, steps o), g), and i). Figure 12 in a to e and Figure 13 ) but advantageously is implemented by at least partially automated means ( Figures 14 to 17 ).

[0135] The method may include a preliminary step o) of bonding the plate 10 to the inner annular surface of the shroud 3.

[0136] The method necessarily comprises four steps a), b), c) and d), which are repeated as required (step e)) a number of times:

[0137] a) preparing a slurry 20 by mixing at least two components,

[0138] b) depositing the slurry 20 onto the inner annular surface 10d of the plate 10,

[0139] c) spreading the slurry 20 by means of at least one roller 24, which extends substantially parallel to the axis A and is arranged to roll on guide rings 26 disposed on both sides of the plate or cladding and coaxial with the guide rings, so as to form an angular section 4a of the wearable layer, the angular section 4a extending around the axis A by a predetermined angle, and

[0140] d) forming a chamfer 28 at the circumferential ends of the thus formed section 4a.

[0141] During step e), steps a) to d) are repeated until a plurality of successive angular sections 4a of the wearable layer 4 are formed and cover the entire inner surface of the plate 10. The sections formed in step e) all include circumferential ends as described below: the circumferential ends cover the chamfered circumferential ends of the previously deposited sections (see Figure 10 ).

[0142] Preferably, the housing 3 is positioned such that the axis A is substantially horizontal during steps b) to e).

[0143] Preferably, the slurry is based on epoxy resin, and preferably, the slurry is filled with, for example, glass microspheres. The slurry is obtained by mixing at least two components.

[0144] Preferably, step a) of preparing the slurry 20 is carried out by a mixer. Thus, it is not done by hand, because manual operation is liable to cause air bubbles to appear in the slurry, and due to the viscosity of the slurry, air bubbles appear in the polymerized wearable layer.

[0145] Figure 11 Such a mixer is shown schematically. In step a), the components are incorporated into a vessel 40 of the mixer, the vessel including at least one rotary mixing element 42 along two non-parallel rotary axes Y and Y.

[0146] For example, the mixer is a DAC3000 of FlackTek.

[0147] The rotating element 42 of the mixer rotates about the axes X, Y for a time of 50 seconds to 200 seconds (preferably 80 seconds to 120 seconds) at a speed of 400 revolutions per minute to 1000 revolutions per minute (preferably 600 revolutions per minute to 900 revolutions per minute).

[0148] Preferably, the dish 40 in which the slurry is mixed has a bottom 40a which can be removed and withdrawn by axial translation from the inside to the outside of the dish. For example, the displacement (see arrow 44) can be done by a piston resting on the lower surface of the bottom 40a. When the bottom 40a is removed from the dish 40, the upper surface of the bottom can be scraped to remove all the slurry and facilitate the placement of the slurry in the next step.

[0149] The mass of the slurry deposited and used to form the section in step b) can be between 400 g and 2600 g.

[0150] Figure 12 a to e in show the steps of the manual completion method. Figure 12 a in shows step b) of depositing the slurry 20 in the form of balls or strings on the inner annular surface 10d of the plate 10.

[0151] Figure 12 b and c in show step c): First, the slurry 20 is spread on the surface 10d by a roller 22 capable of distributing the slurry ( Figure 12 b in), and then the slurry is spread a second time by a shaping roller 24 (the shaping roller can rest on the guide ring 26) to give the slurry a corrected thickness so that the thickness of the slurry is uniform ( Figure 12 c in).

[0152] Then, the slurry 20 extends over a predetermined angular section of the surface 10d, and in step d), a chamfer 28 is made at the circumferential edge of the slurry so that during step e), the slurry deposited and spread on adjacent angular sections can cover the chamfered edge ( Figure 12 d, e in and Figure 13 ).

[0153] Figure 14 And the following figures show the steps of the method as completed by an automated device.

[0154] Figure 14 The device 50 in particularly includes:

[0155] - A device 52 for rotating the housing 3 about the axis A during step c) or each step c),

[0156] - A device 54 for preparing the slurry 20 based on the mixture described above,

[0157] - An apparatus 56 for depositing the slurry 20 in the form of balls or strings on the inner surface of the plate 10,

[0158] - An optional apparatus 58 for scraping the slurry 20 and preforming the slurry before spreading,

[0159] - An apparatus 60 for spreading the slurry using the roller 24 to form each section 4a of the wearable layer,

[0160] - An optional apparatus 62 for unwinding the plastic film 62 and inserting the plastic film 20 between the slurry and the spreading roller 24 of the apparatus 60,

[0161] - An optional apparatus 64 for scraping the inner surface of each section 4a after spreading, and

[0162] - An apparatus 66 for cutting the circumferential ends of each section to form the chamfer 28.

[0163] The apparatus 52 may include a motor that is connected to a drive wheel of the housing 3 about the axis A by a sprocket.

[0164] Preferably, the apparatus 54 includes a mixer 40 of the type described above in connection with Figure 11 description. As Figure 14 shown, the mixer is connected to a reservoir 54b by a pump 54a, and the reservoir is for storing the components to be mixed to form the slurry.

[0165] The apparatus 56 includes a head for depositing the slurry, and the head is movable along one or more axes to optimize the deposition of the slurry on the inner surface of the plate 10.

[0166] Figure 15 The apparatus 58 shown includes at least one blade 58a that is for contacting the slurry 20 in the form of balls or strings to squeeze the slurry and force the slurry to be applied and spread on the plate, and preforming the slurry to facilitate spreading of the slurry by the roller 24.

[0167] The spreading roller 24 is visible in Figure 16 and includes, for example, a first coating roller 24a, a second preforming roller 24b, and a third finishing roller 24c. As described above, these rollers 24 roll on the guide rings 26 mounted on each side of the plate 10.

[0168] As shown in the figure, preferably, the roller 24 is shaped and non-cylindrical so as to impart to the inner surface of the section 4a Figure 1 the desired non-cylindrical shape shown.

[0169] For example, the roller 24 is made of plastic material. The roller 24a enables a slurry thickness that is 1 mm greater than the final desired measurement to be obtained. The roller 24b enables a slurry thickness that is 0.5 mm greater than the final desired measurement to be obtained. The roller 24c enables a slurry thickness that is the desired final measurement to be obtained.

[0170] Preferably, the guide rings 26 are axially pulled towards each other and pressed against the plate 10 by an elastic band 65 extending between the guide rings 26. In a particular example, the guide rings 26 located on each side of the housing 3 include a first ring 26a for rolling the roller 24 and a second ring 26b for holding the first ring 26a. The inner diameter of the first ring is D1, and the inner diameter of the second ring is D2, where D2 is greater than D1.

[0171] The second ring 26b abuts against the first ring 26a, and the first ring is inserted between the second ring and the plate 10. The second ring 26b carries a hook 66 for attaching the first end of the elastic band 65, and the opposite end of the elastic band is attached to the hook 66 carried by the second ring 26b located on the opposite side of the housing 3. Thus, the second ring 26b is axially pulled towards each other by stretching the elastic band 65, and thus axially holds the first ring 26a on both sides of the plate 10.

[0172] The rings 26a and 26b are made of carbon fiber, for example.

[0173] Figure 17 The purpose of the device 62 shown is to insert a plastic film 62 between the slurry 20 and the roller 24, which prevents the risk of direct contact and adhesion between the slurry and the spreading roller 24.

[0174] Then the roller 24a can be used to ensure the positioning of the film and press the film onto the slurry. The roller 24b can ensure the deformation of the film and shape the slurry.

[0175] The device 64 is similar to Figure 15 the device in, and may include at least one blade 58a for contacting the already formed section 4a in order to make the surface condition of the inner surface of the section more perfect.

[0176] In Figure 16 the visible device 68 may include a cutting roller or disc 70 for separating the layer 4 from each side of the plate 10 and facilitating demolding after polymerization. They can also be used to cut the circumferential ends of each section 4a in order to form Figure 13 the chamfer 28 visible in (when such cutting is not performed manually).

[0177] The thickness of the abradable layer 4 is between 3 mm and 10 mm, preferably between 5 mm and 8 mm. The chamfer 28 formed in step d) extends over the entire axial dimension of the section 4a and is oriented at approximately 45° to the normal of the inner surface of this section.

[0178] In the next step f), the slurry polymerizes. This can be carried out at room temperature or in an oven.

[0179] Finally, the method can include a final step g): finishing the inner surface of the abradable layer 4, during which the housing 3 is positioned such that its axis A is substantially vertical.

Claims

1. A casing (3) of an aircraft turbine, the casing comprising: - An annular shroud (9) that extends around an axis (A) and is made of a composite material that includes fibers woven and embedded in a resin, - An annular layer (4) of a wear-resistant material that extends around the axis (A) within the annular shroud and is obtained by spreading and polymerizing a slurry, and - A plurality of support plates (10) that extend around the axis (A) and are inserted between the annular shroud and the annular layer of the wear-resistant material, characterized in that the annular layer of the wear-resistant material is deposited on an inner annular surface of a foam layer (18), and the foam layer itself is deposited on an inner annular surface (10d) of the support plates (10).

2. The housing (3) according to claim 1, wherein, The thickness of the foam layer (18) is between 1 mm and 7 mm.

3. The housing (3) according to claim 2, wherein, The sum of the thicknesses of the annular layer (4) of the wear-resistant material and the foam layer (18) is less than or equal to 10 mm.

4. The housing (3) according to any one of the preceding claims, wherein, The foam layer (18) is made of a thermoplastic material.

5. The housing (3) according to any one of claims 1 to 3, wherein, The density of the foam layer (18) is between 20 Kg / m 3 and 100 Kg / m 3 .

6. The housing (3) according to any one of claims 1 to 3, wherein, The annular layer (4) of the wear-resistant material is associated with at least one fiber reinforcement selected from: a) reinforcing fibers (12); or b) reinforcing rings or fabrics (14).

7. The housing (3) according to claim 6, wherein, The support plates (10) are separated from each other by a gap (J) that is filled with the slurry, and at least a part of the reinforcing rings or fabrics (14) covers the gap.

8. The housing (3) according to claim 2, wherein, The thickness of the foam layer (18) is between 3 mm and 5 mm.

9. The housing according to claim 3, wherein, The sum of the thicknesses of the annular layer (4) of the wear-resistant material and the foam layer (18) is less than or equal to 8 mm.

10. An aircraft turbine comprising a casing (3) according to any one of the preceding claims.

11. The aircraft turbine according to claim 10, wherein, The casing extends around a fan of the aircraft turbine.

12. A method of manufacturing a housing (3) according to any one of claims 1 to 9, wherein, The method comprises the following steps: - Bonding the support plates (10) to an inner annular surface of the annular shroud (9), - Bonding the foam layer (18) to the inner annular surface (10d) of the support plates (10), and - Preparing the slurry and spreading the slurry on the inner annular surface of the foam layer (18).

13. The method according to claim 12, wherein, Before spreading the slurry, reinforcing fibers (12) are mixed into the slurry, or before the slurry is spread on the inner annular surface of the foam layer (18), reinforcing rings or fabrics (14) are arranged on the inner annular surface.

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