Method for manufacturing an annular aircraft turbine engine casing

Abstract

The invention relates to a method for manufacturing a turbine engine casing comprising a skin and tubular vents, comprising the following steps: (a) producing the skin (40) from composite material comprising openings (400), (b) producing the vents (42) from composite material, (c) fixing the vents (42) to the skin (40), these vents (42) being attached at the openings (400), this step (c) comprising, for each vent: (C2) a first operation for welding a carrier (420) to the skin (40) at one of the through-openings (400), and (C4) a second operation for welding a sleeve (426) to the carrier (420) and / or skin (40), the assembly formed by the carrier (420) and the sleeve (426) forming the tubular vent (42), wherein the first (C2) and second (C4) welding operations are carried out by means of a laser (7).

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR MANUFACTURED AN ANNULAR TURBONIACHINE CASING FOR AN AIRCRAFT

[0003] Technical field of the invention

[0004] The field of the present invention is that of turbomachine housings, particularly for aircraft. The present invention relates particularly to a method for manufacturing an annular turbomachine housing, an annular housing obtained by such a manufacturing method, a stage comprising such a housing, and a turbomachine comprising the housing or the stage.

[0005] Technical background

[0006] The prior art includes, in particular, documents US-A-5308226, US-A1-2019 / 105857 and BE-A1-1026006.

[0007] In a turbomachine, particularly an aircraft turbomachine, a stage of variable-pitch blades is mounted, for example, between the rotating wheels of a turbomachine compressor. These blades can be arranged in an annular row in one or more stages, generally of the turbomachine compressor.

[0008] These vanes (also called stator vanes or VSV for "Variable Stator Vane") are carried by an external annular housing and are adjustable in position around their axes of rotation (or otherwise called pitch axes) to optimize the flow of gases in the turbomachine engine.

[0009] Each blade comprises a first pivot at its outer radial end and a second pivot at its inner radial end. These first and second pivots define the blade's pitch axis. The first pivot is mounted in a housing on the outer annular casing. The angular pitch of these blades is designed to adapt the turbomachine's compressor geometry to its operating point. The angular pitch also optimizes compressor efficiency as a function of aircraft speed and maximizes the turbomachine's pumping margin to reduce fuel consumption during different phases of flight.

[0010] The outer annular casing comprises an annular skin and tubular chimneys projecting from an annular outer face of the skin. These chimneys can form housings within the casing and are therefore configured to receive the first variable-pitch blade pivots of the turbomachine stage.

[0011] The mounting (or in other words the assembly) of the chimneys on the casing skin can prove complex when the casing and the chimneys are made, for example, of composite material.

[0012] For example, a housing with directly integrated chimneys can be manufactured. However, this method can be complex to implement, particularly due to the relatively complex and compact geometry of the areas where the chimneys are located. Indeed, the distance between the first pivots of two successive variable-pitch blades is on the order of 20 to 30 mm.

[0013] The chimneys can also be bonded to the casing. However, this type of assembly may have a short lifespan due to aging and the potentially high temperatures in this environment.

[0014] As for assembly by clamping using rivets or screws, it is not feasible due to the size of the parts, which are generally too small, and the limited space.

[0015] In this context, it is interesting to overcome at least some of the drawbacks of the prior art by proposing a new way of making an annular turbomachine casing, and in particular by optimizing and simplifying the integration of the chimneys on this casing.

[0016] Summary of the invention: The present invention aims to overcome one or more drawbacks of the prior art by proposing a solution that is simple, effective and economical.

[0017] The invention thus proposes a method for manufacturing an annular turbomachine casing, in particular for aircraft, this casing comprising an annular skin extending around an axis A and tubular chimneys projecting on an annular external face of the skin and oriented radially with respect to the axis A,

[0018] the process comprising the following steps:

[0019] (a) fabrication of the skin in composite material, this skin having radially through holes,

[0020] (b) construction of tubular chimneys in composite material, and

[0021] (c) fixing the tubular chimneys to the skin, these tubular chimneys being attached at the level of the skin penetration orifices, this step (c) comprising, for each tubular chimney:

[0022] (c₂) a first welding of a support onto the skin at the level of one of the through-holes, and

[0023] (c4) a second welding of a socket onto the support and / or the skin, the assembly formed by the support and the socket forming said tubular chimney.

[0024] According to the invention, the first (c2) and second (c4) welds are carried out by laser.

[0025] Thus, this solution achieves the aforementioned objective. In general, laser welding according to the invention allows for the efficient, effective, and rapid assembly of composite material parts (i.e., tubular chimneys directly onto the casing skin). Indeed, the laser emits a beam that is absorbed directly by the skin, which is the most opaque component compared to the support and / or the tubular chimney's sleeve. This generates heat at the interface between the tubular chimney and the skin, creating a strong and localized bond between the two. This localized heating at the interface(s) to be welded helps to limit the risk of deformation outside the welded interfaces. Therefore, the laser welding process of the invention ensures a durable and long-lasting attachment of the chimneys to the casing skin.

[0026] Unlike ultrasonic welding, laser welding according to the invention does not require direct contact with the interfaces to be welded. This also eliminates the deformation problems encountered during contact welding of the parts to be welded with the energy source.

[0027] Furthermore, laser welding is an alternative to induction welding, which requires the use of at least one susceptor.

[0028] Furthermore, the proposed solution makes a significant contribution to limiting environmental impacts, particularly by avoiding the disposal of parts with welding defects and / or by improving the lifespan of welded parts.

[0029] The term "composite material" refers to a material based on a polymer (such as a thermoplastic material), and possibly including reinforcing fibers.

[0030] The manufacturing process according to the invention may include one or more of the following features, taken individually or in combination with each other:

[0031] - the laser emits a beam configured to pass through the support and / or the socket and to be absorbed by the skin, so as to perform the first (c₂) and second (c₄) welds;

[0032] - at substep (c₄), the socket is welded either simultaneously to the skin and the support, or separately to the skin and then to the support or vice versa, by one or more laser(s);

[0033] - the laser welding speed is less than 15 m / s 1 , and preferably between 1 and 10 ms -1 - the power generated by the laser is less than 150 W, and preferably between 10 and 100 W;

[0034] - the wavelength emitted by the laser is less than 2 pm, and preferably between 0.8 and 1.1 pm;

[0035] - the laser used is an Nd / YAG source laser, a diode laser or a fiber laser;

[0036] - Step (c) further includes:

[0037] (c₁) an initial application of pressure to each support on the skin, this substep (c₁) being carried out before substep (c₂), and / or

[0038] (c₃) a second pressurization of each socket on the corresponding support and skin, this substep (c₃) being carried out before substep (c₄);

[0039] - the skin comprises a thermoplastic material reinforced with continuous fibers;

[0040] - the support and the socket are made of thermoplastic material, and possibly filled with short fibers which have a length of less than 10 mm;

[0041] - the support includes a tubular portion which is mounted radially through the corresponding through orifice;

[0042] - the support includes an annular collar which is pressed against an inner annular face of the skin, opposite the outer face, the support being welded to the skin via its collar;

[0043] - the socket is attached and fixed from the outside of the skin;

[0044] - the socket is mounted around the support, more specifically around the tubular portion, and fixed to the support by laser welding;

[0045] - the thermoplastic material of the support and / or the socket is chosen from the polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or low melting point polyaryletherketone (LM-PAEK), the polyimide family, such as polyetherimide (PEI), and polyethylene sulfide (PPS);

[0046] - the short fibers of the support and / or the socket are carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers;

[0047] - the thermoplastic material of the skin is identical to that of the support and / or the socket;

[0048] - the thermoplastic material of the skin is chosen from the polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or low melting point polyaryletherketone (LM-PAEK), the polyimide family, such as polyetherimide (PEI), and polyethylene sulfide (PPS);

[0049] - continuous skin fibers are carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers;

[0050] - step (c) further includes a substep (es) of cooling each support welded to the skin, and each socket welded to the support and / or the skin.

[0051] The invention also relates to an annular housing for an aircraft turbomachine, this housing being obtained by a manufacturing process according to one of the features of the invention. The support and the sleeve forming the tubular chimney are fixed to the casing by laser welding.

[0052] The annular casing may include:

[0053] - a skin with an annular shape around an axis A, comprising an inner annular face and an outer annular face,

[0054] - tubular chimneys projecting from the outer face of the skin and oriented radially with respect to axis A, each of these chimneys being formed by a support fixed by welding in a through hole in the skin and by a socket fixed by welding to the support and / or to the skin.

[0055] The invention also relates to a stage for an aircraft turbomachine, comprising at least:

[0056] - an annular housing according to the invention,

[0057] - an annular row of variable pitch blades, each variable pitch blade comprising a blade including a cylindrical pivot at its radially external end, this cylindrical pivot being mounted in one of the tubular chimneys of the casing and defining a pitch axis C of the blade;

[0058] - a control ring for the blade timing, this ring extending around the casing and being connected to the cylindrical pivots of the blades.

[0059] The invention further relates to an aircraft turbomachine comprising at least one casing according to the invention, or at least one stage according to the invention.

[0060] Brief description of the figures

[0061] The invention will be better understood and other details, features and advantages of the invention will become more apparent upon reading the following description, given by way of non-limiting example and with reference to the accompanying drawings, in which:

[0062] Figure 1 is a schematic half-view in axial section representing a variable-pitch blade stage of an aircraft turbomachine according to the invention;

[0063] Figure 2 is a schematic half view in axial and partial cross-section of the floor of Figure 1;

[0064] Figure 3 is a schematic perspective and partial view of an annular casing of the stage of Figure 1 or 2; Figure 4 is a schematic half axial cross-sectional view of the casing of Figure 3 having an annular skin and a tubular chimney fixed to this skin;

[0065] Figure 5 is a block diagram representing steps in a manufacturing process for the housing shown in Figure 3 or 4;

[0066] Figure 6 is a schematic half-view in axial section representing an example of welding a chimney support to the casing skin; Figure 7 is a schematic half-view in axial section representing an example of welding a chimney bushing to the casing skin; Figure 8 is a schematic half-view in axial section representing an example of welding the bushing to the support.

[0067] Elements having the same functions in different implementations have the same references in the figures.

[0068] Detailed description of the invention

[0069] In general, in the description below, the terms "longitudinal" and "axial" refer to the orientation of structural elements extending along a longitudinal axis. This axis can be considered the axis of rotation of a turbomachine rotor. The term "radial" refers to the orientation of structural elements extending perpendicular to the longitudinal axis. The terms "inner" and "outer," and "internal" and "external," are used to refer to positioning relative to the longitudinal axis. Thus, a structural element extending along the axis has an inner surface facing the axis and an outer surface opposite its inner surface. Similarly, the terms "upstream" and "downstream" are defined in relation to the direction of airflow within the turbomachine.

[0070] This application applies generally and without limitation to a turbomachine 10, in particular an aircraft turbomachine. The turbomachine 10 may be a turbojet or a turboprop. The turbomachine 10 may extend along a longitudinal X-axis.

[0071] Classically, the turbomachine 10 can include, from upstream to downstream in the direction of gas flow, a blower, one or more compressor stages (for example, a low-pressure compressor and a high-pressure compressor), a combustion chamber, one or more turbine stages (for example, a high-pressure turbine and a low-pressure turbine), and a gas exhaust nozzle.

[0072] The turbomachine 10 may include at least one stage 1, known as the variable pitch blade 1 stage 2.

[0073] Figure 1 partially illustrates a part of this turbomachine 10 comprising several stages 1. This part of turbomachine 10 may correspond to a part of the low pressure compressor and / or the high pressure compressor.

[0074] Each floor 1 includes:

[0075] - a 4-ring casing,

[0076] - an annular row of 2 variable-pitch blades,

[0077] - a control ring 5 for adjusting the blades 2.

[0078] Each variable-pitch blade 2 (or, in other words, fixed blades with respect to the X-axis) comprises a blade 20. The blade 20 includes a first cylindrical pivot 22 at its radially external end (with respect to the X-axis). The first cylindrical pivot 22 is mounted in one of the tubular chimneys 42 of the housing 4.

[0079] The first cylindrical pivot 22 can be centered and guided in rotation in this chimney 42 for example by cylindrical rings 46 which can be mounted around the first cylindrical pivot 22.

[0080] The first cylindrical pivot 22 defines a pitching axis C of the blade 2. This pitching axis C can be inclined with respect to a plane perpendicular to the X axis.

[0081] With reference to figure 2, the first cylindrical pivot 22 can be fixed for example by means of a nut to a control lever 24 (or a connecting rod). This lever 24 allows each of the first cylindrical pivots 22 to be connected to the control ring 5.

[0082] With reference also to Figure 2, the blade 20 and the first cylindrical pivot 22 can be connected by a disc 28 (or in other words a plate) extending substantially perpendicular to the alignment axis C, in a corresponding housing 44 of the housing 4. A radially internal surface 280 of the disc 28 can be aligned with an internal annular face 404 of the skin 40 of the housing 4, so as not to oppose the gas flow.

[0083] The distance between first adjacent cylindrical pivots 22 of blades 2 can be for example between 20 and 30 mm.

[0084] Referring to Figure 1, the blade 20 may also include a second cylindrical pivot 23 at its radially internal end (with respect to the X-axis). This second cylindrical pivot 23 may also define the pitch axis C. The second cylindrical pivot 23 may be supported by a fixed structure of the turbomachine. In particular, the second cylindrical pivot 23 may be engaged in a housing 230 of this fixed structure.

[0085] The variable-pitch blades 2 can be supported by the housing 4, in particular by means of the first cylindrical pivots 22. The angular orientation of the blades 2 can be adjusted to optimize the gas flow, particularly in the compressor of the turbomachine 10. This adjustment can be made by the control ring 5.

[0086] The control ring 5 extends around the housing 4 and is connected to the first cylindrical pivots 22 of the variable pitch blades 2.

[0087] With reference to figure 2, the ring 5 can extend around the X axis, and in particular around the housing 4. An angular displacement of the control ring 5 around the X axis can be transmitted by the levers 24 to the first cylindrical pivots 22 of the blades 2 and makes them rotate around their shimming axes C.

[0088] Each stage 1 may also include an annular row of movable blades 3. With reference to Figure 1, the movable blades 3 may be located downstream of the variable-pitch blades 2. These movable blades 3 may extend around the X-axis. The movable blades 3 may be supported by a rotor 30 of the turbomachine 10.

[0089] The housing 4 according to the invention is illustrated by way of non-limiting example in figures 1 to 4.

[0090] The casing 4 includes an annular skin 40 extending around an axis A. This axis A can correspond substantially to the longitudinal axis X of the turbomachine 10.

[0091] The skin 40 includes an external annular face 402 (hereafter referred to as external face 402) which is oriented radially with respect to the axis A. The skin 40 may include the internal annular face 404 (hereafter referred to as internal face 404) which is opposite the external face 402.

[0092] With reference to figures 2 to 4, the skin 40 includes 400 radially traversing orifices.

[0093] With reference to Figure 3, the distance d between adjacent through-skin orifices 400 can, for example, be between 5 and 20 mm. Preferably, this distance d can be between 9 and 12 mm.

[0094] Skin 40 is made of composite material. Advantageously, skin 40 can be made of thermoplastic material and optionally reinforced with continuous fibers. In other words, skin 40 can be made of a composite material based on thermoplastic material and optionally reinforced with continuous fibers.

[0095] The thermoplastic material for skin 40 can be chosen from: - the polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or low melting point polyaryletherketone (LM-PAEK),

[0096] - the polyimide family, such as polyetherimide (PEI), and

[0097] - polyethylene sulfide (PPS).

[0098] The continuous fibers of the skin 40 can be carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers

[0099] The term "continuous fibers" refers to flat fibers (or strands) that are generally unidirectional and have a circumferential dimension extending around axis A that is substantially greater than their diameter. Unlike discontinuous fibers, continuous fibers are neither fragmented nor sectioned, their circumferential dimension being sufficient to extend over all, or most, of the specified application or reinforcement area. In the case of skin 40, the circumferential dimension of the continuous fibers may exceed 60% of the total circumferential length of that skin 40.

[0100] The housing 4 includes tubular chimneys 42 projecting from the outer face 402 of the skin 40. These chimneys 42 are oriented radially with respect to the axis A. The chimneys 42 are attached at the level of the orifices 400 passing through the skin 40.

[0101] Each first cylindrical pivot 22 of the blades 2 can extend inside the corresponding tubular chimney 42 of the casing 4.

[0102] The 42 tubular chimneys are made of composite material. Advantageously, the 42 chimneys can be made of thermoplastic material, and optionally reinforced with short fibers less than 10 mm long. In other words, the 42 chimneys can be made of a thermoplastic-based composite material, and optionally reinforced with short fibers less than 10 mm long.

[0103] With reference to figures 3 and 4, each chimney 42 can include a support 420.

[0104] The support 420 may include a tubular portion 420a which is mounted radially through the corresponding through orifice 400 of the skin 40. The tubular portion 420a may be frustoconical, as illustrated in Figure 4. The support 420 may include an annular collar 420b which is pressed against the inner face 404 of the skin 40.

[0105] The support 420 may include a cylindrical passage 420c provided in particular for the passage of the first cylindrical pivot 22 of the blade 2. This passage 420c may extend through the tubular portion 420a and the flange 420b.

[0106] The 420 support can be made of thermoplastic material, and optionally filled with short fibers that are less than 10 mm long.

[0107] The thermoplastic material of the 420 support can be chosen from the polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or low melting point polyaryletherketone (LM-PAEK), the polyimide family, such as polyetherimide (PEI), and polyethylene sulfide (PPS).

[0108] The 420 support made of thermoplastic material can be reinforced with a short fiber charge of between 40 and 60%.

[0109] The short fibers of the 420 support can be carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers.

[0110] The short fibers of the 420 support can be carbon microfibers (micro-fillers) with a concentration between 20 and 30%, and preferably between 25 and 30%.

[0111] The thermoplastic material of the support 420 can be identical to that of the skin 40.

[0112] With reference to figure 4, each chimney 42 can include a socket 426.

[0113] The sleeve 426 can be mounted around the support 420, and more specifically around the tubular portion 420a of the support 420. For this purpose, the sleeve 426 may have a complementary shape to the support 200, and more precisely to the tubular portion 420a. The sleeve 426 may include an opening 426a through which the tubular portion 420a of the support 420 extends. This opening 426a of the sleeve 426 may be frustoconical, particularly when the tubular portion 420a has a frustoconical shape.

[0114] The 426 socket can be made of thermoplastic material, and optionally filled with short fibers that are less than 10 mm long.

[0115] The thermoplastic material of the 426 socket can be chosen from the polyaryletherketone (PAEK) family, such as polyetherketone (PEK), polyetheretherketone (PEEK), polyetherketoneketone (PEKK) or low melting point polyaryletherketone (LM-PAEK), the polyimide family, such as polyetherimide (PEI), and polyethylene sulfide (PPS).

[0116] The 426 socket made of thermoplastic material can be reinforced with a short fiber charge of between 40 and 60%.

[0117] The short fibers of the 426 socket can be carbon fibers, glass fibers, ceramic fibers (such as silicon carbide, glass, or aramid), polyamide fibers, metallic fibers, oxide fibers, or a mixture of at least two of these fibers.

[0118] The short fibers of the 426 socket can be carbon microfibers (micro-fillers) with a concentration between 20 and 30%, and preferably between 25 and 30%.

[0119] The thermoplastic material of the sleeve 426 can be identical to that of the support 420 and / or the skin 40.

[0120] The support 420 and the socket 426 can thus form the chimney 42.

[0121] According to one of the features of the invention, the support 420 and the socket 426 are fixed to the skin 40 by laser welding 7. With reference to figures 5 to 8, the present application will now describe a method of manufacturing the housing 4 as described above.

[0122] The process of the invention comprises the following steps:

[0123] (a) production of skin 40 in composite material,

[0124] (b) fabrication of the tubular chimneys 42 in composite material, and (c) fixing of the tubular chimneys 42 to the skin 40, these tubular chimneys 42 being attached at the level of the orifices 400 passing through the skin 40.

[0125] Step (c) of the process comprises, for each tubular chimney 42: (C2) a first welding of the support 420 onto the skin 40 at one of the through-holes 400, and

[0126] (c4) a second welding of the sleeve 426 onto the support 420 and / or the skin 40, the assembly formed by the support 420 and the sleeve 426 forming the tubular chimney 42.

[0127] In the process of the invention, the first (c2) and second (c4) welds are carried out by laser 7. This makes it possible to assemble the chimneys 42 on the skin 40 efficiently, quickly and permanently over time.

[0128] Figure 5 summarizes the steps of the manufacturing process of the invention, in which the optional steps are represented by dotted lines.

[0129] In step (a), the skin 40 can be produced either by weaving fibers in two dimensions (2D) or three dimensions (3D), or by draping and / or winding several layers / plies of fibers (i.e., in the form of multilayers), and consolidated with a polymer resin, for example, in an oven or autoclave. This polymer resin can be the thermoplastic material described above.

[0130] In step (a), through holes 400 can be machined in the skin 40. These holes 400 can be machined through in a radial direction. In step (b), the tubular chimneys 42 can be formed by machining the supports 420 and the bushings 426.

[0131] The machining of each support 420 can include the fabrication of the tubular portion 420a and the flange 420b, the tubular portion 420a being configured to pass radially outwards through one of the through holes 400 machined in the skin 40. The support 420 can be made as a single block comprising the tubular portion 420a and the flange 420b attached to one end of the tubular portion 420a. Alternatively, the support 420 can be made in two blocks that can be assembled, the first block comprising the tubular portion 420a and the second block comprising the flange 420b.

[0132] The machining of each bushing 426 may include at least the creation of the orifice 426a having a shape complementary to that of the tubular portion 420a of the machined support 200. Thus, if the tubular portion 420a has a frustoconical shape, the machined orifice 426a will also have a frustoconical shape.

[0133] Following steps (a) and (b) of making the skin 40 and the tubular chimneys 42, step (c) of fixing these chimneys 42 onto the skin 40 is carried out. This fixing can be done by several laser welds 7.

[0134] At least one or more laser 7 (or laser source(s) 7) can or can be used to carry out substeps (C2) and (C4).

[0135] The laser 7 can emit a beam 70 configured to pass through the support 420 and / or the socket 426 and to be absorbed by the skin 40, so as to perform the first (c2) and second (c4) welds. In particular, the continuous fibers (such as carbon fibers) composing the composite material of the skin 40 allow the beam 70 to be absorbed.

[0136] The welding speed of laser 7 can be less than 15 ms -1 , and preferably between 1 and 10 ms -1 This welding speed can be applied during substep (C2) and / or substep (C4). The power generated by laser 7 can be less than 150 W, and preferably between 10 and 100 W. This power can be applied during substep (02) and / or substep (C4).

[0137] The wavelength emitted by laser 7 can be less than 2 μm, and preferably between 0.8 and 1.1 μm. This wavelength can be applied during substep (02) and / or substep (C4).

[0138] The laser 7 used can be an Nd / YAG source laser, a diode laser or a fiber laser.

[0139] During the welding of each support 420, the tubular portion 420 can be mounted through-bolted in a radially external direction, i.e., from the inner face 404 to the outer face 402 of the skin 40. The support 420 can thus be attached and welded to the skin 40 from the inside of the skin 40, via the flange 420b. The skin 40 is then radially sandwiched between the sleeve 426 and the flange 420b.

[0140] Figure 6 illustrates a non-limiting example of welding the support 420 to the skin 40. The beam 70 passes through the support 420, which is transparent to the beam waves, to be absorbed by the opaque skin 40. At least one laser source 7 can be located near the flange 420b to heat and weld this flange 420b to the inner face 404 of the skin 40. This laser 7 can then be removed to weld the socket 426 to the support 420 and / or the skin 40.

[0141] The laser 7 during substep (C4) can be static or mobile to homogenize the welding.

[0142] Following the welding of the supports 420 onto the skin 40, each socket 426 is welded onto the support 420 and / or the skin 40.

[0143] During substep (c4), the bushing 426 can be welded either simultaneously to the skin 40 and the support 420, or separately to the skin 40 and then to the support 420, or vice versa, by one or more lasers 7. During the welding of the bushing 426, the latter can be mounted around the support 420, and more specifically around the tubular portion 420a. The bushing 426 can be attached to the support 420, and in particular to its tubular portion 420a, in a radially internal direction (approaching the axis A of the skin 40 of the housing 4). The skin 40 is then radially interposed between the sleeve 426 and the collar 420b welded to the inner face 404 of the skin 40, as illustrated in figures 7 and 8. Thus, the sleeve 426 can be attached and fixed from the outside of the skin 40.

[0144] A free end 420d of the support 420, and specifically of its tubular portion 420a, opposite the end of the support 420 comprising the collar 420b, can pass through the orifice 426a of the socket 426 and may include a portion opening above this orifice 426a. This portion of the free end 420d may include a radial dimension dR (Figures 4 and 7) which may be, for example, on the order of 5 to 10 mm.

[0145] Figure 7 illustrates a non-limiting example of welding the socket 426 to the skin 40. The beam 70 passes through the socket 426, which is transparent to the beam waves, to be absorbed by the opaque skin 40. As illustrated in Figure 7, at least one laser source 7 (for example, similar to that of substep (C2)) can be positioned near and above the socket 426 to heat and weld this socket 426, more specifically an internal annular surface 426b of the socket 426, to the external face 402 of the skin 40. This laser 7 can then be removed after the socket 426 has been welded to the skin 40.

[0146] Figure 8 illustrates a non-limiting example of welding the sleeve 426 to the support 420. The beam 70 passes through the sleeve 426, which is transparent to the beam waves, to be absorbed by the tubular portion 420a of the support 420, which is opaque. For this purpose, the tubular portion 420a can be made of a composite material reinforced with short fibers (such as carbon fibers).

[0147] As illustrated in Figure 8, at least one laser source 7 (for example similar to that of substep (es)), can be located near and to the side of the socket 426 to heat and weld the tubular portion 420a of the support 420 inside the orifice 426a of this socket 426. This laser 7 can then be removed after welding the support 420, in particular the tubular portion 420a, to the socket 426.

[0148] The laser 7 during substep (C4) can be static or mobile to homogenize the welding.

[0149] Advantageously, the socket 426 can be welded simultaneously onto the skin 400 and the support 420, notably by several lasers 7.

[0150] After the sub-steps (c2) and (c4) of welding, the assembly including the support 420 and the socket 426 then forms the tubular chimney 42.

[0151] Step (c) may further include:

[0152] (c1) an initial pressurization of each support 420 onto the skin 40, this substep (c1) being carried out before substep (c2), and / or

[0153] (c3) a second pressurization of each socket 426 on the corresponding support 420 and skin 40, this substep (c3) being carried out before substep (c4).

[0154] Substep (c1) compacts the skin 40 (particularly the inner face 404) and the support 420 (particularly the collar 420b) together. Substep (c3) compacts the skin 40 (particularly the outer face 402), the sleeve 426, and / or the support 420 (particularly the tubular portion 420a) together.

[0155] The pressurization is indicated by arrows in Figures 6 to 8. Advantageously, the first pressurization can be maintained during the first weld of substep (C2), as illustrated in Figure 6. The second pressurization can be maintained during the second weld of substep (e), as illustrated in Figures 7 and 8.

[0156] Substeps (c1) and (c3) can be carried out with a pressure between 2 and 10 bars, and preferably between 3 and 6 bars.

[0157] Substeps (c1) and (c3) can be carried out using a pressure tool, for example, a hydraulic or pneumatic one. In particular, this pressure tool may include a borosilicate glass or quartz window to allow the 70 beam to pass through for welding.

[0158] Step (c) may also include a substep (c5) for cooling each tubular chimney 42 welded to the skin 40, this substep (c5) being able to be carried out after substep (c4). This allows for the cooling of each support 420 welded to the skin 40, and of each socket 426 welded to the support 420 and / or the skin 40.

[0159] For example, substage (es) can be achieved by natural convection. As an example, cooling at substage (es) can be achieved by directing a jet of compressed air onto the welded area(s), such as each support 420 welded to the skin 40, and / or each bushing 426 welded to the support 420 and / or the skin 40. According to another example, cooling at substage (c5) can be achieved by conduction through a fluid circulation (such as air or water) via cooling channels machined, in particular, in the pressure tool.

[0160] Advantageously, the second pressurization can be maintained during the cooling of the substage (c5).

[0161] The method according to the invention may also include a step (d) of forming cylindrical through-holes 420c in the support 420, this step (d) being carried out after step (c), more particularly after substep (c5). In particular, the through-hole 420c may be formed in each tubular portion 420a of the support 420, for example by machining.

Claims

DEMANDS 1. Method for manufacturing an annular turbomachine (10) casing (4), in particular for an aircraft, this casing (1) comprising an annular skin (40) extending around an axis (A) and tubular chimneys (42) projecting on an annular external face (402) of the skin (40) and oriented radially with respect to the axis (A), the process comprising the following steps: (a) fabrication of the skin (40) in composite material, this skin (40) having radially passing orifices (400), (b) fabrication of the tubular chimneys (42) in composite material, (c) fixing of the tubular chimneys (42) to the skin (40), these tubular chimneys (42) being attached at the level of the through-holes (400) in the skin (40), this step (c) comprising, for each tubular chimney (42): (c₂) a first welding of a support (420) onto the skin (40) at the level of one of the through holes (400), and (c4) a second welding of a socket (426) onto the support (420) and / or the skin (40), the assembly formed by the support (420) and the socket (426) forming said tubular chimney (42), characterized in that the first (c2) and second (c4) welds are carried out by laser (7).

2. Manufacturing method according to claim 1, characterized in that the laser (7) emits a beam (70) configured to pass through the support (420) and / or the socket (426) and to be absorbed by the skin (40), so as to carry out the first (c2) and second (c4) welds.

3. A manufacturing method according to claim 1 or 2, characterized in that, in substep (c4), the sleeve (426) is welded either simultaneously to the skin (40) and the support (420), or separately to the skin (40) and then to the support (420), or vice versa, by one or more lasers (7).

4. A manufacturing method according to any one of the preceding claims, characterized in that the welding speed by the laser (6) is less than 15 ms. 1 , and preferably between 1 and 10 ms' 1 .

5. A manufacturing method according to any one of the preceding claims, characterized in that the power generated by the laser (6) is less than 150 W, and preferably between 10 and 100 W.

6. A manufacturing method according to any one of the preceding claims, characterized in that the wavelength emitted by the laser (6) is less than 2 µm, and preferably between 0.8 and 1.1 µm.

7. A manufacturing method according to any one of the preceding claims, characterized in that the laser (6) used is an Nd / YAG source laser, a diode laser or a fiber laser.

8. A manufacturing process according to any one of the preceding claims, characterized in that step (c) further comprises: (c1) a first pressurization of each support (420) on the skin (40), this substep (c1) being carried out before substep (c2), and / or (c3) a second pressurization of each socket (426) on the corresponding support (420) and the skin (40), this substep (c3) being carried out before substep (c4).

9. A manufacturing method according to any one of the preceding claims, characterized in that the skin (40) comprises a continuous fiber-reinforced thermoplastic material.

10. A manufacturing method according to any one of the preceding claims, characterized in that the support (420) and the socket (426) are made of thermoplastic material, and optionally filled with short fibers which have a length of less than 10 mm.

11. Annular housing (4) for an aircraft turbomachine (10), said housing (4) being obtained by a manufacturing process according to any one of the preceding claims, characterized in that the support (420) and the sleeve (426) forming the tubular chimney (42) are fixed to the skin (40) by laser welding (7).

12. Stage (1) for an aircraft turbomachine (10), comprising at least: - an annular housing (4) according to claim 11, - an annular row of variable pitch blades (2), each variable pitch blade (2) comprising a blade (20) including a cylindrical pivot (22) at its radially external end, this cylindrical pivot (22) being mounted in one of the tubular chimneys (42) of the casing (4) and defining a pitch axis (C) of the blade (2); - a control ring (5) for setting the blades (2), this ring (5) extending around the casing (4) and being connected to the cylindrical pivots (22) of the blades (2).

13. Aircraft turbomachine (10) comprising at least one casing (4) according to claim 11, or at least one stage (1) according to claim 12.

Images