METHOD FOR MANUFACTURING A HOUSING FOR AN AIRCRAFT TURBOMACHINE

Abstract

A method for manufacturing a turbomachine housing, comprising: - a first step of manufacturing an annular shell of axis A made of composite material, in a mold (64) which has an annular cavity (68) for additional reception of the preform (64) during which a resin is injected into said cavity (68), then polymerized, - a second step during which at least one axial stop means (70) is disposed internally in the shell (16), - a third step during which the annular cartridge made of abradable material is disposed inside the annular shell in contact with said axial stop means (70), - a fourth step of bonding the annular cartridge (30) made of abradable material onto the first internal annular surface (38), characterized in that the first and second steps are simultaneous and in that said at least one axial stop means (70) is molded with the preform (66) in the mold (64).Figure for the abbreviation: Figure 8.

Description

Title of the invention: METHOD FOR MANUFACTURED A HOUSING FOR AN AIRCRAFT TURBOMACHINE Technical field of the invention

[0001] The present invention relates to the manufacture of a casing, in particular a blower casing, for an aircraft turbomachine. Technical background

[0002] The prior art includes in particular documents FR-A1-2 997 725, FR-Al-2 997 726, and FR-A1-3 005 100.

[0003] In a known manner, a twin- or triple-spool turbomachine comprises, from upstream to downstream, i.e., in the direction of gas flow, a fan, at least one low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, at least one low-pressure turbine, and a nozzle for expelling the combustion gases exiting the turbines. A rotor of the high-pressure compressor is connected to a rotor of the high-pressure turbine by a high-pressure shaft, and these rotors thus form a high-pressure casing. At least one rotor of a low-pressure compressor is connected to a rotor of a low-pressure turbine by a low-pressure shaft, and these rotors thus form at least one low-pressure casing. The low-pressure shaft passes coaxially through the high-pressure shaft and drives, directly or via a reduction gear, a rotor of the fan.

[0004] The fan comprises a blade wheel surrounded by a fan housing, also called a retention housing due to its function of retaining the blades in the event of their breakage or the entry of debris into the fan. Such a housing consists of an axial annular shell extending around the turbomachine's fan blades and comprising an upstream annular section internally carrying upstream acoustic panels, a downstream section internally carrying downstream acoustic panels, and an intermediate section, arranged axially between the upstream and downstream sections, comprising a first internal annular surface to which is attached an annular cartridge of abradable material, made in one piece or segmented. The fan housing is connected, upstream, to an air inlet sleeve and downstream, to a ferrule of an intermediate housing of the turbomachine.

[0005] In addition to its retention function, the blower housing ensures the continuity of the aerodynamic stream via the annular cartridge made of abradable material. It also ensures mechanical continuity of forces and moments between the air inlet sleeve and the intermediate housing's ferrule. Furthermore, it allows for the attachment of various equipment and supports, ensuring compliance with specifications. fire and leakage regulations, and to allow continuity of electrical current for the turbomachine's lightning resistance.

[0006] The annular cartridge of abradable material is for example made in the form of a ferrule produced by injection molding or in the form of an assembly of sectors.

[0007] The annular cartridge is conventionally immobilized axially relative to the casing so as to coincide axially with the intermediate section of the casing provided for this purpose. To achieve this, the intermediate section of the casing conventionally has, at at least one of its ends, a series of axial stops which are fixed to an inner circumference of the casing, to receive the annular cartridge as a buttress, in order to define its position.

[0008] The annular cartridge is then clamped in the casing and subjected to a bonding step on the first internal annular surface, during which the casing is heated and held and compressed by means of a removable system disposed at least partially inside the casing. Thanks to this removable system, a mechanical pressure force is applied to the annular cartridge, allowing it to be held in position during the heating step. The bonding is carried out in an autoclave.

[0009] Conventionally, axial stops are attached to the casing. For example, the casing receives pads, each having a longitudinal portion extending along the first internal annular surface and a transverse portion extending perpendicularly to the longitudinal portion and forming an axial stop. The longitudinal portion has holes intended to be passed through by screws allowing each pad to be fixed to the casing.

[0010] This technical solution involves pre-drilling the casing according to a rigorous positioning, then mounting each of the pads, which increases the manufacturing cost of such a casing.

[0011] There is therefore a need for a turbomachine housing equipped with one or more axial stop means of simple design not requiring complex assembly operations. Summary of the invention

[0012] The invention meets this need by proposing a method for manufacturing a turbomachine housing comprising one or more axial stop means integrated directly into the casing during its manufacture.

[0013] To this end, the invention proposes a method for manufacturing an aircraft turbomachine casing, comprising at least:

[0014] - a first manufacturing step of an annular envelope extending around a axis A and comprising at least one intermediate section intended to receive an annular cartridge made of abradable material, during which an annular preform of axis A of the envelope, made of composite material comprising 3D woven fibers, is placed in a mold which has an additional annular cavity for receiving the preform, then during which a resin is injected into said cavity, and then the resin is polymerized,

[0015] - a second step in which at least one axial stop means is arranged projecting from a first internal annular surface of the intermediate section of the envelope, at a first end of said intermediate section,

[0016] - a third step during which the annular cartridge made of material The abradable element is disposed inside the annular envelope in contact with said axial stop means, covering said first annular surface,

[0017] - a fourth step of bonding the annular cartridge made of abradable material onto the first internal annular surface, during which the casing is heated and maintained by means of a system present at least partially inside the casing,

[0018] characterized in that the second step occurs simultaneously with the first step and in that during said second step, said at least one axial stop means is molded with the preform in the mold.

[0019] This design makes it possible to produce a housing casing in which the stop means are integrated into the casing during its manufacture and which have the advantage of not requiring costly and time-consuming operations after the manufacture of the casing.

[0020] According to other features of the process:

[0021] - the axial stop means molded with the preform is in the shape of a bead annular with axis A,

[0022] - the mold used during said first and second steps comprises a shell an outer annular ring with axis A and an inner annular shell with axis A between which the cavity is delimited, and the inner shell has an annular groove with axis A which opens into the cavity and which is suitable for being filled with resin during its injection into the cavity, to form said bead after polymerization of the resin and demolding,

[0023] - during the third step, the annular cartridge made of abradable material is secured inside the envelope by means of at least one removable fastening device.

[0024] The invention also relates to an annular casing with axis A of a turbine housing molded by resin injection from an annular preform made of 3D woven fibers, characterized in that it comprises at least one inter annular median which is intended to receive an annular cartridge of abradable material and of which a first internal annular surface has at least one axial stop means which projects from said first internal annular surface and which is molded with the resin of said casing.

[0025] According to other characteristics of the envelope:

[0026] - the axial stop means is an annular bead with axis A molded with resin the envelope,

[0027] - the axial stop means is an annular bead with axis A made entirely and only with the resin from the casing,

[0028] - the bead has a thickness or radial dimension between 10 and 30 mm and / or an axial width or dimension between 2 and 3mm.

[0029] The invention also relates to a mold for manufacturing an annular shell of a turbomachine casing of the type described above, characterized in that it comprises an outer annular shell of axis A with an inner annular cavity and an inner annular shell of axis A with an outer annular cavity, said cavities delimiting a cavity of the mold, said shells being able to be disposed respectively outside and inside the preform so that the cavity receives a preform and is filled with resin by injection, characterized in that an intermediate section of the inner shell comprises an annular groove of axis A formed in the outer annular cavity and able to be filled with resin.

[0030] The invention finally relates to a twin-flow aircraft turbomachine comprising a fan casing of the type described above. Brief description of the figures

[0031] Other features and advantages of the invention will become apparent upon reading the detailed description that follows, for an understanding of which reference should be made to the accompanying drawings in which:

[0032] [Fig-1] Fig. 1 is a cross-sectional view of a turbomachine blower aircraft according to the state of the art;

[0033] [Fig.2] Fig.2 is a perspective view of a blower housing according to the state of the technique;

[0034] [Fig.3] The [Fig.3] already discussed shows a schematic partial section of a blower housing according to the state of the art;

[0035] [Fig.4] Fig.4 is a perspective view of a blower housing in a state of holding an annular cartridge made of abradable material, in which the annular cartridge is sandwiched between two sets of pads, during a gluing step thereof;

[0036] [Fig. 5] [Fig. 5] is an enlargement of a detail of [Fig. 5] showing a skate a part of the annular cartridge;

[0037] [Fig.6] Fig.6 is a cutaway perspective view of the casing of a housing. blower according to the invention;

[0038] [Fig.7] Fig.7 is a perspective view illustrating the bonding of a cartouche annular made of abradable material in a casing of a blower housing according to the invention;

[0039] [Fig.8] Fig.8 is a schematic cross-sectional view of a mold for the manufacturing of an annular casing for a turbomachine housing according to the invention.

[0040] [Fig.9] Fig.9 is a block diagram illustrating the manufacturing steps of a casing according to the invention. Detailed description of the invention

[0041] A fan 10 of an aircraft turbomachine is shown in [Fig.1] in partial view.

[0042] In a known manner, a twin- or triple-spool turbomachine comprises, from upstream to downstream, i.e., in the direction of gas flow, a fan, at least one low-pressure compressor, a high-pressure compressor, a combustion chamber, a high-pressure turbine, at least one low-pressure turbine, and a nozzle for expelling the combustion gases exiting the turbines. One rotor of the high-pressure compressor is connected to one rotor of the high-pressure turbine by a high-pressure shaft, thus forming a high-pressure casing. At least one rotor of a low-pressure compressor is connected to one rotor of a low-pressure turbine by a low-pressure shaft, thus forming at least one low-pressure casing. The low-pressure shaft passes coaxially through the high-pressure shaft and drives, directly or via a reduction gear, one rotor of the fan.

[0043] The blower 10 includes a blade wheel 12 which is surrounded by a blower housing 14, also called a retention housing because of its function of retaining the blades in case of breakage of the latter, or in case of entry of debris into the blower.

[0044] In the remainder of this description, the invention is applied to a blower housing 14. The invention is not limited to this type of housing, however, and can be applied to other housings of a turbomachine.

[0045] As can be seen particularly in [Fig. 2], the fan housing 14 comprises an annular casing 16 with axis of revolution A extending around the fan blades 12 of the aforementioned turbomachine. This casing includes an annular mounting flange 18, 20 at each of its axial ends. These flanges 18, 20 are used to fix the housing 14 to annular walls of the turbomachine nacelle.

[0046] As illustrated more particularly by the schematic cross-section in [Fig. 3], the casing The blower 14 is connected upstream to an air inlet sleeve 22 and downstream to a ferrule 24 of an intermediate housing. The housing 14 also carries upstream acoustic panels 26 and downstream acoustic panels 28. The blower housing 14 further includes an annular cartridge 30 of abradable material, positioned on an internal annular surface of the casing, between the upstream panels 26 and the downstream panels 28.

[0047] This cartridge 30 can be made either in the form of an annular ferrule, or in the form of panels forming angular sectors of the ferrule, which are assembled together.

[0048] The housing 14 comprises, as previously seen, an annular casing 16 extending around the axis A, which is made of a composite material comprising woven fibers embedded in a resin. The casing 16 has an upstream section 32, adapted to receive the upstream acoustic panel 26, a downstream section 34, adapted to receive the downstream acoustic panel 26, and an intermediate section 36, adapted to receive the cartridge 30 of abradable material.

[0049] The annular cartridge 30 covers a first internal annular surface 38 of the intermediate section 36, while the upstream acoustic panel 26 is fixed to a second internal annular surface 40 of the upstream section 3,2 for example by means of screwing means 41, and the downstream acoustic panel 26 is fixed to a third internal annular surface 42 of the downstream section 34, for example by means of screwing means 43.

[0050] The annular cartridge 30 is intended to be fixed by gluing onto the first internal surface 38 of the envelope 16.

[0051] To do this, the cartridge 30 is placed in a unique axial position within the casing 14, and then immobilized therein. A bonding step then takes place, during which the casing 14 is subjected to a heat treatment under pressure.

[0052] Figure 5 illustrates a housing 14 equipped with a tool 44 according to a prior art for immobilizing the housing 14 in the intermediate section 36 of the casing 16. This tool 44 consists here of two sets 46, 48 of pads 50, 52. With the exception of the elements (pins, pins, fasteners, etc.) used to hold the pads 50, 52, and possibly fix them to the housing 3, the tool 44 does not include any other parts and is therefore relatively simple.

[0053] In practice, during the gluing operation, and more specifically during the heating operation, the housing 14 is placed in an autoclave (not shown) so that its axis A is oriented vertically.

[0054] A pressurization system 54 can be mounted inside the housing 14, this system 54 being schematically represented in [Fig. 5]. This system 54 occupies a part of the internal space of the housing 14 and the tooling 44 is designed to take this constraint into account.

[0055] The pads 50, 52 allow the cartridge 30 to be axially immobilized in the intermediate section 36 by forming axial stop means.

[0056] In the example shown here, the tooling 44 comprises two series 46, 48 of pads 50, 52 forming axial stops, but this configuration is not limiting of the invention, and the tooling could comprise only one series 46 or 48 of pads 50 or 52 to receive as a stop a first end of the cartridge 30, the latter being axially immobilized in another way at its second opposite end.

[0057] Fig. 4 illustrates the detail of a pad 50 forming an axial stop means known from the prior art.

[0058] The skid 50 comprises a longitudinal portion 56 and a transverse portion 58. The longitudinal portion 56 is intended to be removably mounted against the casing 16 and more specifically against the respective first internal annular surface 38 of the intermediate section 36 intended to receive the cartridge 30 of abradable material, at one end of this section 36. To this end, the longitudinal portion 56 has at least one hole 60 which is intended to be passed through by a fastening means (not shown) such as a screw, a pin, a dowel, or a fastener, etc., which is received in the intermediate section 36.

[0059] The transverse portion 58 is designed to extend transversely to the longitudinal portion 56. The transverse portion 58 has a contact surface 62 intended to support the cartridge 30 of abradable material. The pad 50 can be made in two parts, the longitudinal portion 56 being positioned in contact with the respective first internal annular surface 38 of the intermediate section 36 and fixed by means of the aforementioned screws, before the transverse portion 58 is mounted onto the longitudinal portion 56.

[0060] Each series 46, 48 of pads 50, 52 comprises between 4 and 20 pads distributed regularly, i.e. equidistant, around the perimeter of the end of the intermediate section 36 of the casing. The bearing load of the cartridge 30 is thus distributed homogeneously circumferentially.

[0061] Thus, a prior art manufacturing method for a housing 14 comprises a first manufacturing step of the annular casing 16, during which, conventionally, an annular preform with axis A of the casing, made of a composite material comprising 3D woven fibers, is placed in a mold having an additional annular cavity for receiving the preform. A resin is then injected into said cavity, and the resin is subsequently polymerized. This design being widely documented in the prior art, it is mentioned only for the record and will not be described in greater detail.

[0062] Then, in a second step, a first series 48 of pads 52 forming as many means of axial stop is arranged in projection from the first internal annular surface 38 of the intermediate section 36 of the envelope 16, at a first end of said intermediate section 36.

[0063] Then in a third step, the annular cartridge 30 made of abradable material is placed inside the annular envelope 16 in contact with the pads 52 covering the first annular surface 38. A second series 46 of pads 50 are then placed, forming as many means of axial stop projecting from the first internal annular surface 38 of the intermediate section 36 of the envelope 16, at a second end of the intermediate section 36.

[0064] Then during a fourth bonding step, the annular cartridge 30 made of abradable material is bonded to the first internal annular surface 38. During this step, the housing 16 is heated and held by means of a system present at least partly inside the housing. In particular, this system includes the pressurization system 54 which forces the cartridge 30 into contact with the casing 16.

[0065] This configuration is generally satisfactory but requires on the one hand preparation operations of the envelope 16 and on the other hand positioning and assembly operations of the pads 50, 52, which increases the total manufacturing cost of the housing 14.

[0066] The invention remedies this drawback by proposing a method for manufacturing a turbomachine housing 14 incorporating one or more axial stop means directly integrated into the casing 16 during its manufacture.

[0067] As before, and as illustrated in [Fig.9], the manufacturing process of the housing 14 according to the invention includes a first step ET1 of manufacturing an annular envelope extending around an axis A and comprising at least one intermediate section 36 similar to that previously described which is intended to receive an annular cartridge 30 of abradable material similar to that previously described.

[0068] During this step ET1, as illustrated in [Fig.9], an annular preform 66 with axis A of the envelope 30, made of composite material and comprising 3-dimensionally woven fibers, is placed in a mold 64 which has an annular cavity 68 for receiving the preform 64, then a resin is injected into this cavity, and then the resin is polymerized.

[0069] Then, similarly to the method which is the subject of the technique, during a second step ET2, at least one axial stop means 70 is disposed projecting from the first internal annular surface 38 of the intermediate section of the envelope 36, at a first end of this intermediate section.

[0070] The difference between the process that is the subject of the invention and the process according to the state The technical aspect lies in the fact that, according to the invention, the second step ET2 occurs simultaneously with the first step ET1, and in that during this second step ET2, this axial stop means 70 is molded with the preform 66 in the mold 64.

[0071] The axial stop means 70 molded with the preform 66 can take different forms. It can initially consist of a pad substantially similar to the pads 52 previously described, which would not be fixed to the casing but overmolded in the resin with the preform 66 to be integrated into the casing.

[0072] However, preferably, as illustrated in [Fig.6], during this second step ET2 the axial stop means 70 molded with the preform to constitute the envelope 30 is in the form of an annular bead with axis A.

[0073] In its simplest expression, the axial stop means 70 is an annular bead that could be obtained from an annular ring 78 which would be received with the preform 66 in the mold 64. For this purpose, as illustrated in [Fig. 8], the mold 64 used during the first and second stages comprises an outer annular shell 72 with axis A and an inner cavity 73 and an inner annular shell 74 with axis A and an outer cavity 75. The cavity 68 is delimited between the shells 72, 74 and more particularly by the cavities 73, 75. The inner shell 74 has an annular groove 76 with axis A which opens into the cavity 68 and which is suitable for reviewing the ring 78, which has been represented here in dashed lines, before the resin injection.

[0074] More particularly, an intermediate section 77 of the inner shell has the annular groove 76 of axis A formed in the outer annular cavity which is suitable for being filled with resin, and this section 77 defines the counter-form of the intermediate section 36 of the envelope 16 which is intended to receive the cartridge 30.

[0075] The bead 70 therefore results from the overmolding of the ring 78 with the preform 66 with the resin of the envelope 30, and the ring 78 is therefore covered with resin in the groove 76.

[0076] However, according to a preferred embodiment of the invention, the groove 76 is intended to be filled with resin only during its injection into the cavity, to form said bead 70 after polymerization of the resin and demolding. In this case, the groove 76 does not receive a bead before the injection of the resin, and the axial stop means 70 is an annular bead with axis A made entirely and solely with the resin of the casing 30.

[0077] In these last two embodiments, as the envelope 16 is oriented vertically for the gluing of the cartridge 30, it will be understood that the final dimensions of the bead 70 are designed to support the weight of the cartridge 30.

[0078] By way of example, the bead 70 typically has a radial thickness or dimension between 10 and 30 mm and / or an axial width or dimension along axis A between 2 and 3 mm.

[0079] It will therefore also be understood in both embodiments that in order to obtain a bead 70 capable of supporting the weight of the cartridge 30, the dimensions of the groove 76 must be calculated judiciously, and in particular for the last embodiment in which the volume of the groove must be provided to generate an annular bead of resin of sufficient resistance.

[0080] Similar to the prior art method, the method includes a third step ET3 in which the annular cartridge 30 made of abradable material is placed inside the annular envelope 16 in contact with the axial stop means 70, covering said first annular surface 38.

[0081] This configuration is shown in [Fig. 7]. Unlike the prior art method, there is no pressure-generating system mounted inside the housing 14. The cartridge 30 is received against the stop in the sleeve 16 during step ET4 and held in place with a removable clamping device. To this end, an annular disc 80 is positioned under the sleeve 16 and rests against the end of the sleeve 16. This disc 80 receives first jaws 82 of clamps 84 that pass through the cartridge 30, and second jaws 86 clamp the second end 88 of the cartridge 30, thus ensuring retention and clamping.

[0082] The annular cartridge made of abradable material can then be bonded. The housing 14 is heated, for example, to a temperature between 25 and 300°C, and preferably between 80 and 200°C. This operation can be carried out in a cycle lasting between 60 and 500 minutes, and preferably between 180 and 300 minutes.

[0083] At the end of the heating operation, the temperature to which the housing 14 is subjected is lowered. After the housing 14 has completely cooled, the abradable layer 30 is bonded and fixed to the casing 16.

[0084] From an industrial perspective, the invention offers the advantage of improving the manufacturing (repeatability, robustness) and assembly of the housing, as well as its three-dimensional control, since the positioning of the annular layer of abradable material is guaranteed by means of a molded axial stop. The invention thus improves the mechanical and aerodynamic performance of the housing, as well as its manufacturing process, and reduces overall cycle time.

[0085] The invention therefore simplifies the manufacturing operations of a fan casing 16. It thus makes it possible to have a turbofan aircraft engine with a fan casing manufactured according to the manufacturing process described above, thereby reducing overall manufacturing costs.

Claims

Demands

1. A method for manufacturing an aircraft turbomachine housing (14), comprising at least: - a first step (ET1) of manufacturing an annular casing (16) extending around an axis A and comprising at least one intermediate section (36) for receiving an annular cartridge (30) made of abradable material, during which an annular preform (66) with axis A of the casing (16), made of a composite material comprising three-dimensionally woven fibers, is placed in a mold (64) which has an annular cavity (68) for receiving the preform (64), and during which a resin is injected into said cavity (68), and then the resin is polymerized, - a second step (ET2) during which at least one axial stop means (70) is disposed projecting from a first internal annular surface (38) of the intermediate section (36) of the casing (16), at a first end of said intermediate section (36),- a third step (ET3) in which the annular cartridge (30) made of abradable material is placed inside the annular casing (16) in contact with said axial stop means (70), covering said first annular surface (38), - a fourth step (ET4) of bonding the annular cartridge (30) made of abradable material to the first internal annular surface (38), in which the casing (16) is heated and held by means of a system present at least partially inside the casing (14), characterized in that the second step (ET2) occurs simultaneously with the first step (ET1) and in that during said second step (ET2), said at least one axial stop means (70) is molded with the preform (66) in the mold (64).

2. A manufacturing method according to the preceding claim, characterized in that the axial stop means (70) molded with the preform is in the form of an annular bead with axis A.

3. A manufacturing method according to the preceding claim, characterized in that the mold (64) used during said first and second steps comprises an outer annular shell (72) with axis A and an inner annular shell (74) with axis A between which the cavity (68) is delimited, and in that the inner shell (74) comprises an annular groove (76) of axis A which opens into the cavity (68) and which is suitable for being filled with resin when injected into the cavity (68), to form said bead (70) after polymerization of the resin and demolding.

4. A manufacturing method according to any one of the preceding claims, characterized in that during the third step (ET3), the annular cartridge (30) made of abradable material is clamped inside the casing by means of at least one removable clamping device (80, 82, 84, 86).

5. Annular casing (16) of axis A of a turbomachine casing (14) molded by resin injection from an annular preform (66) of 3-dimensional woven fibers, characterized in that it comprises at least one intermediate annular section (36) which is intended to receive an annular cartridge (30) of abradable material and of which a first internal annular surface (38) comprises at least one axial stop means (70) which projects from said first internal annular surface (38) and which is molded with the resin of said casing (16).

6. Annular envelope (16) according to the preceding claim, characterized in that the axial stop means (70) is an annular bead of axis A molded with the resin of the envelope (16).

7. Annular envelope (16) according to any one of claims 5 or 6, characterized in that the axial stop means (70) is an annular bead of axis A made entirely and solely with the resin of the envelope (16).

8. Annular envelope (16) according to any one of claims 6 or 7, characterized in that the rim has a thickness or radial dimension of between 10 and 30 mm and / or a width or axial dimension of between 2 and 3 mm.

9. A mold (64) for manufacturing an annular shell (16) of a turbomachine housing (14) according to claim 7 or 8, characterized in that it comprises an outer annular shell (72) with axis A and an inner annular cavity (73), and an inner annular shell (74) with axis A and an outer annular cavity (75), said cavities (73, 75) defining a cavity (68) of the mold (64), said shells (72, 74) being able to be disposed respectively outside and inside a preform (66) so that the cavity (68) receives the preform (66) and is filled with resin by injection, characterized in that an intermediate section of the inner shell (77) comprises an annular groove (76) with axis A formed in the cavity outer ring (75) and suitable for being filled with resin.

10. Aircraft turbofan engine comprising a fan casing (14) manufactured according to the manufacturing process of claims 1 to 4.

Images