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, (b) producing the vents (42) from composite material, (c) fixing the vents to the skin, this step (c) comprising, for each vent: (c2) welding a carrier (420) to the skin by means of an energy source (6), and (c5) welding a sleeve (426) to the carrier and / or skin by means of the energy source (6), wherein first (422) and second (424) susceptors are located between the carrier and the skin, and between the sleeve and the carrier and / or skin, and a magnetic field-generating element (6) inductively heats the first and second susceptors in sub-steps (c2) and (c5).

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR MANUFACTURING AN ANNULAR CRANKCASE FOR AN AIRCRAFT TURBOMACHINE

[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 the 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] To this end, the invention relates to 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 includes the following steps:

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

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

[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 to the skin at the level of one of the through-holes, by at least one energy source, and

[0023] (es) a second welding of a socket onto the support and / or the skin, by at least one energy source, the assembly formed by the support and the socket forming said tubular chimney.

[0024] According to the invention, first and second susceptors are located at the level, respectively, of at least a first interface between the support and the skin, and of at least a second interface between the socket and the support and / or the skin.

[0025] According to the invention, the energy source is a magnetic field generation element configured to heat the first and second susceptors by induction during substeps (C2) and (es).

[0026] Thus, this solution makes it possible to achieve the aforementioned objective. In general, induction welding according to the invention allows for the efficient, high-performance, and rapid assembly of composite material parts (i.e., the tubular chimneys and the annular casing skin). To this end, the process of the invention incorporates susceptors at the interfaces of the parts to be welded, to achieve localized and uniform heating (and therefore welding) at these interfaces. The susceptors absorb the magnetic field generated by the energy source, thereby rapidly heating the interfaces to be welded. Localized heating at the interfaces to be welded notably limits the risk of deformation outside the interfaces being welded. Thus, the induction welding process of the invention ensures the long-term, durable bonding of the chimneys to the casing skin.

[0027] Unlike ultrasonic welding, induction 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.

[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 "susceptor" refers to an insert that reacts to a magnetic field and converts it into heat to ensure welding.

[0030] The term "composite material" refers to a material based on a polymer (such as a thermoplastic material), and possibly including reinforcing fibers.

[0031] The manufacturing process according to the invention may include one or more of the following features, taken individually or in combination with each other:

[0032] - the first and second susceptors are positioned at the level, respectively, of said first interface before substep (C2) and of said second interface before substep (es), or the first and second susceptors are preformed with each tubular chimney and / or skin;

[0033] - Step (c) further includes:

[0034] (ci) a first pressurization of each support (420) on the skin (40), this substep (m) being carried out before substep (C2), and / or (C4) a second pressurization of each socket (426) on the corresponding support and the skin, this substep (C4) being carried out before substep (es);

[0035] - the first welding of the sub-step (C2) and / or the second welding of the sub-step (es) is carried out at a temperature between 300 and 400°C, and preferably between 350 and 380°C;

[0036] - Step (c) also includes:

[0037] (es) a first cooling of each support welded to the skin, this substep (es) being carried out between substeps (C2) and (es), and / or (ce) a second cooling of each socket (426) welded to the support and / or the skin, this substep (ce) being carried out after step (es);

[0038] - the support and the socket are made of thermoplastic material, and possibly filled with short fibers that are less than 10 mm long;

[0039] - the first susceptor and / or the second susceptor is / are a metallic filament or a thermoplastic film loaded with metallic particles; - the metallic material of the metallic filament or metallic particles is a ferromagnetic metal, such as copper, steel, iron, nickel, cobalt or a mixture of at least two of these metals;

[0040] - The first and / or second susceptor(s) have a thickness of less than 2 mm, and preferably between 0.25 and 1 mm; - The first and / or second susceptor have a maximum surface area of ​​approximately 100 m² 2 ;

[0041] -- the support includes a tubular portion which is mounted radially through the corresponding through orifice; -- the support includes an annular collar which is pressed against an internal annular face of the skin, opposite the external face, the support being welded to the skin via its collar;

[0042] -- the socket is attached and fixed from the outside of the skin;

[0043] -- the socket is mounted around the support, more particularly around the tubular portion, and fixed to the support by induction welding;

[0044] -- the first susceptor is pre-formed on the support, more particularly on the annular collar;

[0045] -- the second susceptor is preformed on the support (more particularly around the tubular portion) and / or the socket (more particularly inside an orifice of the socket and / or on an internal annular surface of the socket);

[0046] -- metallic particles have an average size of less than 100 pm, preferably between 1 pm and 80 pm;

[0047] - the rate of metallic particles in the first susceptor and / or the second susceptor is less than or equal to 60% by volume, and preferably between 1% and 50% by volume;

[0048] - 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);

[0049] - 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;

[0050] -- the skin is made of thermoplastic material, and possibly reinforced with continuous fibers;- the thermoplastic material of the skin is identical to that of the support and / or the socket;

[0051] -- 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);

[0052] - 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.

[0053] 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 first and second susceptors are permanently located within the housing.

[0054] The annular casing may include:

[0055] - a skin with an annular shape around an axis A, comprising an inner annular face and an outer annular face,

[0056] - 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.

[0057] The housing according to the invention may comprise one or more of the following features, taken individually or in combination with each other:

[0058] -- The first and / or second susceptor(s) have a thickness of less than 2 mm, and preferably between 0.25 and 1 mm; -- The first and / or second susceptor have a maximum surface area of ​​approximately 100 m² 2 ;

[0059] -- the support may include a tubular portion inside the orifice passing through in a radial direction;

[0060] -- the support may include a collar fixed to the inner annular surface of the skin.

[0061] The invention also relates to a stage for an aircraft turbomachine, comprising at least:

[0062] - an annular housing according to the invention,

[0063] - 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;

[0064] - a control ring for the blade timing, this ring extending around the casing and being connected to the cylindrical pivots of the blades.

[0065] 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.

[0066] Brief description of the figures

[0067] 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:

[0068] Figure 1 is a schematic half-view in axial section representing a variable pitch blade stage of an aircraft turbomachine according to the invention;

[0069] Figure 2 is a schematic half view in axial and partial section of the stage of Figure 1; Figure 3 is a schematic perspective and partial view of an annular casing of the stage of Figure 1 or 2;

[0070] Figure 4 is a schematic half-view in axial section of the housing of Figure 3 comprising an annular skin and a tubular chimney fixed to this skin;

[0071] Figure 5 is a block diagram representing steps in a manufacturing process for the housing shown in Figure 3 or 4;

[0072] Figure 6 is a schematic half-view in axial section representing an example of pressurizing a chimney support on the casing skin;

[0073] Figure 7 is a schematic half-view in axial section representing an example of welding the chimney support to the casing skin; Figure 8 is a schematic half-view in axial section representing an example of pressurizing a chimney sleeve onto the support and the casing skin;

[0074] Figure 9 is a schematic half-view in axial section representing an example of welding the socket onto the support and the skin.

[0075] Elements having the same functions in different implementations have the same references in the figures.

[0076] Detailed description of the invention

[0077] 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 in a direction 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.

[0078] 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.

[0079] The turbomachine 10 can extend along a longitudinal X axis.

[0080] Classically, the turbomachine 10 can include, from upstream to downstream in the direction of gas flow, a blower, one or more stages of compressors (for example a low pressure compressor and a high pressure compressor), a combustion chamber, one or more stages of turbine (for example a high pressure turbine and a low pressure turbine), and a gas exhaust nozzle.

[0081] The turbomachine 10 may include at least one stage 1, known as the variable pitch blade 1 stage 2.

[0082] 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.

[0083] Each floor 1 includes:

[0084] - a 4-ring casing,

[0085] - an annular row of 2 variable-pitch blades,

[0086] - a control ring 5 for adjusting the blades 2.

[0087] 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.

[0088] 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. 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 axis X.

[0089] Referring 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.

[0090] 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.

[0091] The distance between first adjacent cylindrical pivots 22 of blades 2 can be for example between 20 and 30 mm.

[0092] 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.

[0093] 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.

[0094] The control ring 5 extends around the housing 4 and is connected to the first cylindrical pivots 22 of the variable pitch blades 2.

[0095] 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.

[0096] Each stage 1 may also include an annular row of movable blades 3.

[0097] Referring to Figure 1, the movable blades 3 can be located downstream of the variable-pitch blades 2. These movable blades 3 can extend around the X-axis. The movable blades 3 can be supported by a rotor 30 of the turbomachine 10.

[0098] The housing 4 according to the invention is illustrated by way of non-limiting example in figures 1 to 4.

[0099] 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.

[0100] 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.

[0101] With reference to figures 2 to 4, the skin 40 includes 400 radially traversing orifices.

[0102] 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.

[0103] 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.

[0104] 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), - the polyimide family, such as polyetherimide (PEI), and

[0105] - polyethylene sulfide (PPS).

[0106] 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

[0107] 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.

[0108] 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.

[0109] Each first cylindrical pivot 22 of the blades 2 can extend inside the corresponding tubular chimney 42 of the casing 4.

[0110] 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 in length. In other words, the 42 chimneys can be made of a composite material based on thermoplastic material, and optionally reinforced with short fibers less than 10 mm in length.

[0111] With reference to figures 3 and 4, each chimney 42 may include a support 420. The support 420 may include a tubular portion 420a which is mounted through, in a radial direction, inside the corresponding through orifice 400 of the skin 40. The tubular portion 420a may be frustoconical, as illustrated in figure 4.

[0112] The support 420 may include an annular collar 420b which is pressed against the inner face 404 of the skin 40.

[0113] 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.

[0114] The 420 support 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 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).

[0116] The 420 support made of thermoplastic material can be reinforced with a short fiber charge of between 40 and 60%.

[0117] 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.

[0118] 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%.

[0119] The thermoplastic material of the support 420 can be identical to that of the skin 40. With reference to figure 4, each chimney 42 can include a socket 426.

[0120] 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.

[0121] The 426 socket can be made of thermoplastic material, and optionally filled with short fibers that are less than 10 mm long.

[0122] 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).

[0123] The 426 socket made of thermoplastic material can be reinforced with a short fiber charge of between 40 and 60%.

[0124] 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.

[0125] 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%.

[0126] The thermoplastic material of the sleeve 426 can be identical to that of the support 420 and / or the skin 40. The support 420 and the sleeve 426 can thus form the chimney 42.

[0127] According to one of the features of the invention, the housing 4 may include first 422 and second 424 susceptors which are permanently located in the housing. These susceptors 422 and 424 each form a connection interface between the skin 40 and the chimneys 42, notably via induction welding (described below with reference to the manufacturing process of the housing 4), which is reliable and robust.

[0128] The first susceptor 422 is located at the level of a first interface I422 between the support 420 and the skin 40.

[0129] Referring to Figure 4, the first susceptor 422 can be located between the flange 420b of the support 420 and a first annular portion of the inner surface 404 of the skin, which is situated at the level of the through orifice 400. The first susceptor 422 can be a metallic filament or a thermoplastic film loaded with metallic particles.

[0130] The metallic material of the metal filament or metallic particles of the first susceptor 422 may be a ferromagnetic metal, such as copper, steel, iron, nickel, cobalt or a mixture of at least two of these metals.

[0131] The thermoplastic film of the first susceptor 422 may comprise a thermoplastic material selected 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).

[0132] The thermoplastic material of the thermoplastic film of the first susceptor 422 can be identical to that of the skin 40, the support 420 and / or the sleeve 426.

[0133] The first susceptor 422 may have a thickness of less than 2 mm, and preferably between 0.25 and 1 mm. This thickness may be measured along a plane perpendicular to axis A. The first susceptor 422 may have a maximum surface area of ​​approximately 100 mm². 2 This allows for efficient welding of the 420 support and the 4 skin, in particular without risk of deforming areas outside the first interface to be welded.

[0134] The second susceptor 424 is located at a second interface I424 between the socket 426 and the support 420 and / or the skin 40.

[0135] Advantageously, the second susceptor 424 may comprise a first fragment 424a and / or a second fragment 424b. The first fragment 424a may be located between the tubular portion 420a of the support 420 and the orifice 426a of the socket 426. The second fragment 424b may be located between an internal annular surface 426b of the socket 426 and a second annular portion of the external face 402 of the skin 40 which is located at the level of the through orifice 400.

[0136] Figure 4 illustrates, in a non-limiting manner, the second susceptor 424 located, on the one hand, between the socket 426 and the support 420 via the first fragment 424a, and on the other hand, between the socket 426 and the skin 40 via the second fragment 424b. The socket 426 can be located around the first fragment 424a and / or on the second fragment 424b of the second susceptor 424.

[0137] The first fragment 424a can extend at least partially around the support 420, and more specifically around the tubular portion 420a. The first fragment 424a can extend, in a radial direction, inside the orifice 426a of the socket 426.

[0138] The first fragment 424a may include a complementary form of the tubular portion 420a of the support 420 and the orifice 426a of the socket 426. The second susceptor 424 may be a metallic filament or a thermoplastic film loaded with metallic particles.

[0139] The metallic material of the metal filament or metal particles of the second susceptor 424 may be a ferromagnetic metal, such as copper, steel, iron, nickel, cobalt, or a mixture of at least two of these metals. The thermoplastic film of the second susceptor 424 may comprise a thermoplastic material selected 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).

[0140] The thermoplastic material of the thermoplastic film of the second susceptor 424 can be identical to that of the first susceptor 422, the skin 40, the support 420 and / or the socket 426.

[0141] The second susceptor 424 may have a thickness of less than 2 mm, and preferably between 0.25 and 1 mm. This thickness can be measured along a plane perpendicular to axis A.

[0142] The second susceptor 424 can have a maximum surface area of ​​approximately 100 mm² 2 This allows the support 420 and / or the socket 426 to be welded efficiently with the skin 4, in particular without risk of deforming the areas outside the second interface to be welded.

[0143] With reference to Figures 5 to 9, the present application will now describe a manufacturing process for the housing 4 as described above.

[0144] The process of the invention comprises the following steps:

[0145] (a) production of skin 40 in composite material,

[0146] (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.

[0147] 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, by at least one energy source 6, and

[0148] (es) a second welding of the sleeve 426 onto the support 420 and / or the skin 40, by at least one energy source 6, the assembly formed by the support 420 and the sleeve 426 forming the tubular chimney 42. In the process of the invention, the first 422 and second 424 susceptors are located at the level, respectively, of at least the first interface I422 between the support 420 and the skin 40, and of at least the second interface U24 between the sleeve 426 and the support 420 and / or the skin 40.

[0149] In the process of the invention, the energy source 6 is a magnetic field generation element configured to inductively heat the first 422 and second 424 susceptors during substeps (C2) and (es). The process according to the invention thus makes it possible to assemble the chimneys 42 onto the skin 40 via induction welding, efficiently, quickly, and durably.

[0150] Figure 5 summarizes the steps of the manufacturing process of the invention, in which the optional steps are represented by dotted lines.

[0151] 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.

[0152] During step (a), through holes 400 can be machined in the skin 40. These holes 400 can be machined through in the radial direction.

[0153] In step (b), the tubular chimneys 42 can be formed by machining the supports 420 and the bushings 426.

[0154] 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.

[0155] 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.

[0156] In step (b), the first susceptor 422 can be preformed with each tubular chimney 42. This facilitates the location of the weld at the first interface I422. Alternatively, the first susceptor 422 can be preformed with the skin 40, particularly on the inner face 404 and around one of the through holes 400. For this purpose, the first susceptor 422 can be fixed, by co-consolidation, around the corresponding orifice 400 on the inner face 404 of the skin 40. The first susceptor 422 can thus be co-consolidated with the skin 40, particularly during the manufacturing of the skin 40. Co-consolidation allows the first susceptor 422 to be enveloped (or in other words, imprisoned) within the skin 40. The first susceptor 422 can be covered with a thermoplastic polymer film which may or may not be metal-filled.

[0157] Advantageously, the first susceptor 422 can be preformed on the collar 420b of the support 420. For this purpose, the first susceptor 422 can be fixed, for example by co-consolidation, on the collar 420b in particular during the manufacture of the support 420.

[0158] In step (b), the second susceptor 424, in particular the first fragment 424a and / or the second fragment 424b, can be preformed with each tubular chimney 42. This facilitates weld localization at the second interface I424. Alternatively, the second susceptor 422 can be preformed at least partially with the skin 40, specifically on the outer face 402 and around one of the through holes 400. For this purpose, the second susceptor 424 can be fixed, by co-consolidation, around the corresponding hole 400 on the outer face 402 of the skin 40.

[0159] Advantageously, the second suceptor 424, in particular the first fragment 424a and / or the second fragment 424b, can be preformed with the support 420 and / or the sleeve 426. More particularly, the first fragment 424a can be preformed around the tubular portion 420a of the support 420 or inside the orifice 426a of the sleeve 426; and / or the second fragment 424b can be preformed on the internal surface 426b of the sleeve 426. For this purpose, the second susceptor 424 can be fixed, for example by co-consolidation, to the tubular portion 420a, inside the orifice 426a of the sleeve 426 and / or to the internal surface 426b of the sleeve 426. The second susceptor 422 can thus be co-consolidated with the support 420 and / or the sleeve 426, in particular during the manufacture of the support 420 or the sleeve 426.For example, the first fragment 424a can be co-consolidated with the support 420, particularly during the manufacture of the support 420, and the second fragment 424b can be co-consolidated with the sleeve 426, particularly during the manufacture of the sleeve 426. According to another example, the first 424a and second 424b fragments can be co-consolidated with the sleeve 426, particularly during the manufacture of the sleeve 426.

[0160] 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 achieved by several induction welds of the chimneys 42 onto the skin 40.

[0161] During the welding of each support 420, the tubular portion 420 can be mounted through-through in a radially outward 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 first susceptor 422 is then radially interposed between the skin 40 and the flange 420b, as illustrated in Figures 6 and 7. Figure 7 illustrates a non-limiting example of welding the support 420 to the skin. The first susceptor 422 is located between the inner face 404 of the skin and the flange 420b.

[0162] At least one energy source 6, such as via an inductor, can be located near the collar 420b to heat the first susceptor 422 by induction. This energy source 6 can then be removed to perform the welding of the sleeve 426 and / or the support 420 with the skin 40.

[0163] The energy source 6 can be static or mobile to homogenize the welding.

[0164] Following the welding of the supports 420 to the skin 40, each bushing 426 is welded to the support 420 and / or the skin 40. During the welding of the bushing 426, it 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 first susceptor 422 welded to the collar 420b, as illustrated in figures 8 and 9. Thus, the sleeve 426 can be attached and fixed from outside the skin 40. A free end 420d of the support 420, and more precisely of its tubular part 420a, opposite the end of the support 420 including the collar 420b, can pass through the orifice 426a of the sleeve 426 and can have a portion opening above this orifice 426a.This portion of the free end 420d may include a radial dimension dR (figure 9) which may be, for example, on the order of 5 to 10 mm.

[0165] Figure 9 illustrates a non-limiting example of welding the sleeve 426 to the support 420 and the skin 40. The second susceptor 422 is located, on the one hand, between the skin 40 and the sleeve 426, and on the other hand, between the sleeve 426 and the support 420. More particularly, the first fragment 424a of the second susceptor 424 is located between the external face 402 of the skin 40 and the internal surface 426b of the sleeve; and the second fragment 424b is located between the tubular portion 420a of the support 420 and the orifice 426a of the sleeve 426. At least one energy source 6, such as an inductor, can be located near the sleeve 426 to heat the second susceptor 424 by induction. This energy source 6 can then be removed after welding the sleeve 426 onto the support 420 and / or the skin 40.

[0166] The energy source 6 can be static or mobile to homogenize the welding.

[0167] After the sub-steps (C2) and (es) of welding, the skin 40 can therefore be welded to the support 420, and more specifically to the collar 420b via the first susceptor 422, and possibly the sleeve 426 via the second susceptor 424. The assembly including the support 420 and the sleeve 426 then forms the tubular chimney 42.

[0168] According to one embodiment, the first 422 and second 424 susceptors can be positioned at the level of the first interface I422 before substep (C2) and the second interface U24 before substep (es), respectively. For example, the positioning of the susceptors 422 and 424 can be performed manually. According to another embodiment, the first 422 and second 424 susceptors can be preformed with each tubular chimney 42 and / or the skin 40. The integration of these susceptors 422 and 424 is described in particular above in step (b).

[0169] The first weld of substep (C2) and / or the second weld of substep (es) may be carried out at a temperature between 300 and 400°C, and preferably between 350 and 380°C. This allows the thermoplastic material of the susceptors 422, 424, and optionally of the skin 40 and / or the chimney, to melt so as to bond each tubular chimney 42 to the skin 40. Step (c) may further include:

[0170] (ci) an initial pressurization of each support 420 on the skin 40, this substep (m) being carried out before substep (C2), and / or

[0171] (C4) a second pressurization of each socket 426 on the corresponding support 420 and skin 40, this substep (C4) being carried out before substep (es).

[0172] The substep (m) allows the skin 40 (in particular the inner face 404), the first susceptor 422 and the support 420 (in particular the collar 420b) to be compacted together.

[0173] The substep (C4) allows the skin 40 (in particular the outer face 402), the second susceptor 424, the socket 426 and / or the support 420 (in particular the tubular portion 420a) to be compacted together.

[0174] The pressurization is indicated by arrows in Figures 6 to 9. Advantageously, the first pressurization can be maintained during the first weld of substep (C2), as illustrated in Figure 7. The second pressurization can be maintained during the second weld of substep (es), as illustrated in Figure 9.

[0175] Substeps (m) and (C4) can be carried out with a pressure between 2 and 10 bars, and preferably between 3 and 6 bars.

[0176] Substeps (m) and (C4) can be carried out with pressurization tooling that can be electrically isolated.

[0177] Step (c) may also include:

[0178] (es) a first cooling of each support 420 welded to the skin 40, this substep (es) being carried out between substeps (C2) and (es), and / or (ce) a second cooling of each socket 426 welded to the support 420 and / or the skin 40, this substep (ce) being carried out after step (es). Substep (es) and / or substep (ce) may be carried out by natural convection. As an example, cooling at substep (es) and / or substep (ce) can be achieved by sending a jet of compressed air onto the welded area(s), such as each support 420 welded onto the skin 40, and / or each bushing 426 welded onto the support 420 and / or the skin 40. According to another example, cooling at substep (es) and / or substep (ce) can be achieved by conduction through a fluid circulation (such as air or water) via cooling channels machined in particular in the pressure tool.

[0179] Substep (ce) can be performed by reducing the electrical power of the energy source 6. This reduces the welding temperature and thus controls the cooling of the welded area(s). The electrical power of the energy source 6 can be reduced by a maximum of approximately 99% compared to the welding power. For example, the electrical power of the energy source 6 during welding of substep (C2) and / or substep (es) can be between 3000 W and 6000 W. Advantageously, the initial pressure can be maintained during the first cooling of substep (es). The second pressure can be maintained during the second cooling of substep (ce).

[0180] 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 (es) or (ce). In particular, the through-hole 420c may be formed in each tubular portion 420a of the support 420, for example by machining.

Claims

1. CLAIMS 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 includes 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) to the skin (40) at one of the through-holes (400), by at least one energy source (6), and (es) a second welding of a socket (426) to the support (420) and / or the skin (40), by at least one energy source (6), the assembly formed by the support (420) and the socket (426) forming said tubular chimney (42), characterized in that the first (422) and second (424) susceptors are located at, respectively, at least one first interface (I422) between the support (420) and the skin (40), and at least one second interface (I424) between the socket (426) and the support (420) and / or the skin (40), and in that the energy source (6) is a configured magnetic field generation element to heat by induction the first (422) and second (424) susceptors during substeps (C2) and (es).

2. Manufacturing method according to claim 1, characterized in that the first (422) and second (424) susceptors are positioned at the level, respectively, of said first interface (I422) before substep (C2) and of said second interface (I424) before substep (es), or the first (422) and second (424) susceptors are preformed with each tubular chimney (42) and / or skin (40).

3. A manufacturing process according to claim 1 or 2, characterized in that step (c) further comprises: (ci) a first pressurization of each support (420) on the skin (40), this substep (m) being carried out before substep (C2), and / or (C4) a second pressurization of each socket (426) on the corresponding support (420) and the skin (40), this substep (C4) being carried out before substep (es).

4. Manufacturing method according to any one of the preceding claims, characterized in that the first welding of substep (C2) and / or the second welding of substep (es) is carried out at a temperature between 300 and 400°C, and preferably between 350 and 380°C.

5. A manufacturing process according to any one of the preceding claims, characterized in that step (c) also comprises: (es) an initial cooling of each support (420) welded to the skin (40), this substep (es) being carried out between substeps (C2) and (es), and / or (ce) a second cooling of each socket (426) welded to the support (420) and / or the skin (40), this substep (ce) being carried out after step (C5).

6. 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 loaded with short fibers which have a length of less than 10 mm.

7. A manufacturing method according to any one of the preceding claims, characterized in that the first susceptor (422) and / or the second susceptor (424) is / are a metallic filament or a thermoplastic film loaded with metallic particles.

8. A manufacturing method according to the preceding claim, characterized in that the metallic material of the metal filament or metallic particles is a ferromagnetic metal, such as copper, steel, iron, nickel, cobalt or a mixture of at least two of these metals.

9. A manufacturing method according to any one of the preceding claims, characterized in that the first susceptor (422) and / or the second susceptor (424) has a thickness of less than 2 mm, and preferably between 0.25 and 1 mm.

10. A manufacturing method according to any one of the preceding claims, characterized in that the first susceptor (422) and / or the second susceptor (424) has a maximum surface area of ​​approximately 100 m² 2 .

11. Annular housing (4) for an aircraft turbomachine (10), this housing (4) being obtained by a manufacturing process according to any one of the preceding claims, characterized in that the first (422) and second (424) susceptors are permanently located in the housing (4).

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.

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