BE1023377B1 - AXIAL TURBOMACHINE COMPRESSOR BOSS CASING - Google Patents

Abstract

The invention provides a method of manufacturing an axial turbomachine casing, for example a high pressure compressor or a low pressure compressor. The casing comprises an arcuate wall with an orifice, and a tube extending radially the orifice forming a boss. The method comprising the steps of: (a) providing or making (200) an arcuate wall with an orifice and a surface surrounding the orifice which is radially oriented, followed by (b) orbital friction welding (202) of a tube attached against the radial surface, and in the radial extension of the orifice. The addition of the tube makes it possible to reduce machining by turning the wall from a stamped blank. Milling is also reduced. The invention also improves a turbomachine with defrost lines and steerable vanes (VSV) mounted to the tubes.

Description

Description TECHNICAL FIELD The invention relates to a turbomachine casing having attachment bosses. More specifically, the invention provides a method of manufacturing a boss housing related to equipment of the turbomachine. The invention also relates to an axial turbomachine, in particular an aircraft turbojet engine or an aircraft turboprop engine.

Prior art

The structure of an aircraft turbojet is complex because of the number of elements and their modes of assembly. Several pieces of equipment are rigidly connected to the stator while respecting the imperative of lightness. The housing of the high pressure compressor supports several rows of blades variable pitch, that is to say, tilting relative to the flow. It then becomes possible to change the compression that each compression step adds. The flow is then controlled according to the flow rate and the speed of rotation. To allow this variable setting, the housing comprises a series of drilled bosses in which are articulated variable paddle blades. Pivot links are formed.

Document US 2005/0135926 A1 discloses a turbojet comprising two compressors. One of them is equipped with several rows of variable-pitch vanes whose operation is ensured by rings. The rotation of the latter pivots the control levers disposed at the outer ends of the rockets of each blade in order to modulate the orientation in the flow. Each fuse extends radially and is pivotally mounted in a tube to form a pivotal connection.

The tubes and the rockets are elongated radially in order to increase the rigidity of maintaining the blades. But their elongation increases the outer diameter of the monoblock housing uniting them. Such a housing is generally produced from a crankcase produced by forging. The casing of the crude casing includes the shapes of the tubes, and shows a generally constant thickness.

However, the need to make a thin wall and elongated tubes increases the radial thickness of the machining to be performed. By employing a turning process, the manufacturing time remains long. Milling operations to separate the tubes and to lighten the housing are expensive because of the volume of material to be removed. In addition, the accessibility is reduced between the close tubes which reduces the size of the adapted cutter. The amount of raw material of the starting crankcase represents a significant expense. As a result, the cost of the finished casing remains high. Summary of the invention

TECHNICAL PROBLEM The invention aims to solve at least one of the problems posed by the prior art. More specifically, the invention aims to simplify the production of a turbomachine casing. The invention also aims to provide a simple solution, resistant, lightweight, economical, reliable, easy to produce, convenient maintenance, easy inspection, and improving performance.

TECHNICAL SOLUTION The subject of the invention is a method for manufacturing an axial turbomachine casing, in particular an axial turbomachine compressor, the casing comprising: an arcuate wall with an orifice, and a tube radially extending the orifice, the method comprising the following steps: (a) providing or producing an arcuate wall with an orifice and a surface surrounding the orifice that is radially oriented, characterized in that the method further comprises a step (b) welding a tube against the radial surface and in the radial extension of the orifice.

According to an advantageous embodiment of the invention, in step (b) welding, the welding is a friction welding, in particular an orbital friction welding.

According to an advantageous embodiment of the invention, in step (a) supply or embodiment, the wall comprises an extra thickness surrounding the orifice and on which is formed the radial surface.

According to an advantageous embodiment of the invention, in step (b) welding, the wall comprises an extra thickness surrounding the tube and / or the or each extra thickness optionally forming an annular row of pads or an annular band of material.

According to an advantageous embodiment of the invention, the step (b) welding comprises the establishment of a support against the wall opposite the tube which closes the opening. According to an advantageous embodiment of the invention, in step (a) supply or embodiment, the orifice is a through hole or a blind hole, and / or the orifice comprises two portions superimposed radially and having different sizes.

According to an advantageous embodiment of the invention, in step (b) welding, the wall comprises a chamfer fitting the tube and / or surrounding the tube.

According to an advantageous embodiment of the invention, the step (b) comprises welding a step (b1) manufacture of the tube by additive manufacturing by layers, in particular based on powder and electron beam.

According to an advantageous embodiment of the invention, in step (a) supply or production, the wall comprises several orifices, the step (b1) manufacture of the tube comprises the production of a block of material with several tubes, at the The result of step (b) welding each tube of the block is associated with an orifice of the wall, the block being preferably produced by additive manufacturing by layers, based on powder, and by electron beam.

According to an advantageous embodiment of the invention, the wall is made of titanium or titanium alloy.

According to an advantageous embodiment of the invention, the tube extends the orifice radially outwards and / or the radial surface is an external surface.

According to an advantageous embodiment of the invention, the wall comprises at least one annular row of orifices and at least one annular row of tubes, each tube extending an associated orifice.

According to an advantageous embodiment of the invention, the or each orifice has at least one, possibly two circular profiles.

The presence of an orifice on the wall is not an indispensable aspect of the invention. The invention also relates to a method for manufacturing an axial turbomachine casing, the casing comprising an arcuate wall and a tube radially extending the wall, the method comprising a step of providing and producing a wall with an oriented surface. radially, remarkable in that the method comprises a friction welding step, including orbital, of a tube against the radial surface. The invention also relates to a turbomachine, comprising a housing, which is remarkable in that the housing is derived from the manufacturing method according to the invention, possibly the housing is formed of half-shells.

According to an advantageous embodiment of the invention, the turbomachine comprises a low-pressure compressor, the casing being that of the low-pressure compressor, the tube being disposed at an axial distance from an annular row of stator vanes, preferably axially between two annular rows of stator blades.

According to an advantageous embodiment of the invention, the turbomachine comprises a high pressure compressor, the casing being that of the high pressure compressor, the tube being disposed axially of an annular row of stator vanes.

According to an advantageous embodiment of the invention, the orifice comprises two radial portions of different diameters.

According to an advantageous embodiment of the invention, the casing comprises a radial annular fixing flange whose radial height is less than the radial depth of the orifice.

According to an advantageous embodiment of the invention, the turbomachine comprises a variable-pitch blade with a rod pivotally mounted in the orifice and passing through the tube. According to an advantageous embodiment of the invention, the turbomachine comprises an acoustic panel with a fastener fixed to the orifice, in particular in contact with the tube. According to an advantageous embodiment of the invention, the turbomachine comprises a defrosting and / or cooling duct with a fastener fixed to the orifice in the tube.

According to an advantageous embodiment of the invention, the turbomachine comprises an annular seal, in particular a layer of abradable material disposed axially in line with the tube.

According to an advantageous embodiment of the invention, the wall has a radial thickness less than or equal to 6.00 mm, preferably less than or equal to 4.00 mm, more preferably less than or equal to 3.00 mm.

In general, the advantageous modes of each object of the invention are also applicable to the other objects of the invention. As far as possible, each object of the invention is combinable with other objects.

Advantages The invention allows a marked extension of the tubes without affecting the machining cost, and therefore without significantly impacting the final price of the casing. Thus, the cost of the rigidity of fixing by the tubes only penalizes the cost of the casing moderately. The invention makes it possible to improve the quality of the machining of the tubes. Indeed, they can be made on a dedicated support where the phenomena of cutting forces and vibrations are not penalizing.

In case of nonconformity of a tube after boring or rectification of its internal surface, the correction is simpler to bring. Indeed, it suffices to weld another tube instead of penalizing the crankcase during manufacture. It is also allowed to place an element in the tube and then weld the tube by trapping the element. This avoids the risk of losing said element.

Brief description of the drawings

FIG. 1 represents an axial turbomachine according to the invention.

FIG. 2 illustrates a low-pressure turbomachine compressor casing according to the invention.

FIG. 3 is a sketch of a low-pressure turbomachine compressor casing according to the invention.

Figure 4 shows a method of producing a housing according to the invention. Description of the embodiments

In the following description, the terms inner or inner and outer or outer refer to a positioning relative to the axis of rotation of an axial turbomachine. The axial direction corresponds to the direction along the axis of rotation of the turbomachine. The radial direction is perpendicular to the axis of rotation. Upstream and downstream are in reference to the main flow direction of the flow in the turbomachine.

FIG. 1 is a simplified representation of an axial turbomachine. It is in this case a double-flow turbojet engine. The turbojet engine 2 comprises a first compression level, called a low-pressure compressor 4, a second compression level, called a high-pressure compressor 6, a combustion chamber 8 and one or more levels of turbines 10. In operation, the mechanical power the turbine 10 transmitted via the central shaft to the rotor 12 sets in motion the two compressors 4 and 6. The latter comprise several rows of rotor blades associated with rows of stator vanes. The rotation of the rotor about its axis of rotation 14 thus makes it possible to generate an air flow and to compress it progressively until it reaches the combustion chamber 8.

An inlet fan commonly referred to as fan or blower 16 is coupled to the rotor 12 and generates an air flow which splits into a primary flow 18 passing through the various aforementioned levels of the turbomachine, and a secondary flow 20 passing through an annular duct (partially shown) along the machine to then join the primary flow at the turbine outlet. The secondary flow can be accelerated to generate a thrust reaction. The primary 18 and secondary 20 streams are annular flows, they are channeled by the casing of the turbomachine and / or by ferrules. For this purpose, the housing has cylindrical walls which can be internal and external. In particular, the low pressure compressor and the high pressure compressor each comprise a housing, including an outer casing. The invention also applies to a turbine casing, or to a fan casing.

Reducing means, such as a transmission, can increase the rotational speed transmitted to the compressors, and / or reduce the speed of rotation of the fan. This can be provided by an epicyclic reduction gearbox, the corresponding turbine engine being designated by the English acronym GTF for "Gear TurboFan". The presence of the transmission increases the need for lubrication and cooling.

FIG. 2 is a sectional view of a compressor of an axial turbomachine such as that of FIG. 1. The compressor can be a low-pressure compressor 4. There can be seen a part of the fan 16 and the separation nozzle 22 of the primary stream 18 and the secondary stream 20.

The rotor 12 comprises several rows of rotor blades 24, in this case three. The rotor blades form a one-piece assembly with the rotor. They can be welded on a drum 28 or on discs, for example by friction. They can also be cut in the mass at the same time as the rotor. The rotor and the rotor blades may adopt another technology: they may comprise dovetails inserted into annular retention grooves formed on the rotor.

The low pressure compressor 4 comprises several rectifiers, in this case four, each containing a row of stator vanes 26. The rectifiers are associated with the fan 16 or a row of rotor vanes to straighten the flow of air, so as to convert the speed of the primary flow 18 to static pressure.

The stator vanes 26 extend essentially radially from the outer casing 30 of the compressor 4. They can be fixed and immobilized by means of fixing pins 32 which pass through orifices formed in the arcuate wall 34 of the casing 30. Or again, they may be welded into openings formed in the arcuate wall 34 of the compressor 4. Bonding is also contemplated. Each blade may comprise a fixing platform 36, possibly with a disk resting against the inner surface of the wall 34. In front, the housing 30 may comprise facets against which the platforms are mounted. The casing 34 may comprise one or more internal annular grooves in which the platforms 36 are housed. These grooves allow locking in rotation thanks to their shoulders.

The stator vanes 26 are regularly spaced from each other, and have the same angular orientation in the stream 18. Advantageously, the blades 26 of the same row are identical. Optionally, the spacing between the vanes may vary locally as well as their angular orientations. Some blades 26 may differ from the rest of the blades of their row. The housing 30 may be formed of several axially coupled rings, or half-shells. It may comprise several quarters each covering an angular portion, for example a quarter, a fifth or an eighth of a turn.

The wall 34 may have a profile of revolution about the axis 14. This profile of revolution may extend mainly axially. It can be generally straight, or substantially curved. It can move closer to axis 14 downstream. The wall 34 may be delimited upstream by an annular fixing flange 38 extending radially. The annular flange 38 allows the attachment of the separation spout 22. A downstream flange (not shown) may axially delimit the wall 34 and allow attachment to the intermediate fan casing of the turbomachine. An intermediate radial annular flange may be provided, it may be formed by a row of tubes. Such an intermediate flange can form a ring reinforcing circularly the wall 34.

The casing 30 may comprise an upstream portion, possibly in the form of an outer shell, which is connected to the separating lip 22. This ferrule may be made of an organic matrix composite material. The wall 34 of the housing 30 may be mixed, it may comprise an axial composite section, and another axial metal section. The wall 34 can be extended downstream by an acoustic panel 40. This can be fixed on the arcuate wall 34 of the casing 30, in particular at the level of orifices extended by tubes 42. These tubes 42 are commonly called bosses. The tubes 42 are advantageously welded to the casing 30, more exactly to the outer surface of its wall 34. This outer surface may comprise portions in which the tubes 42 are welded. The tubes 42 may comprise internal threads to allow fixation. reversible. The tubes 42 are advantageously arranged between the rows of stator vanes 24. They may be at the right of circular seals 44, for example of abradable material cooperating with the ends of the rotor blades 24. The material of the seal 44 can plug an orifice through a tube 42 and the wall 34.

The separation spout 22 may comprise a deicing device, or anti-icing device. This device is capable of deicing the separation spout 22, and / or of melting an accumulation of frost. For this purpose, the device comprises a circuit for the circulation of a deicing fluid, for example oil or a hot gas (e). The gas can be taken from the low-pressure compressor 4 or into the high-pressure compressor, and can be reinjected into the stream of the primary stream 18. The gas may possibly come from a turbine. The oil can be lubricating oil of the turbomachine equipment. It can lubricate bearings of the rotor shafts, or a reduction transmission linked to the fan 16.

In parallel, the oil cools in contact with the separation spout 22 which then forms a heat exchanger. The circuit comprises a network of conduits 46, some of which are attached to the tubes 42.

Figure 3 outlines an angular portion of the housing 130 of high pressure compressor. This FIG. 3 repeats the numbering of the preceding figures for identical or similar elements, however, the numbering is incremented by 100. Specific numbers are used for the elements specific to this embodiment. The upstream and downstream attachment flanges 138 are shown.

The housing 130 has an arcuate wall 134. It describes a complete circle or a fraction of a turn, for example a semicircle. The wall 136 comprises at least one orifice 148, preferably several orifices 148. The orifices 148 may be arranged in one or more annular rows, or in angular portions of annular row.

At least one or each orifice 148 is extended radially by means of a tube 142. Thus, the orifices 148 pass through both the wall 134 and the tubes 142. At the level of the upstream row 150 each tube 142 is isolated from its neighbors, while that in the downstream row 152 the tubes 142 are joined to their neighbors. Conversely, the upstream tubes can be joined, and the downstream tubes can be isolated. Several tubes 142 joints can come from the same block of material; they can come from matter. Although only two rows (150; 152) of tubes 142 are shown, the housing 130 may comprise three, four or more rows (150; 152) of tubes 142 associated with orifices 148.

At least one or each orifice 148 is stepped. A step orifice 148 comprises several circular portions of different diameters. That of greater diameter may be radially inward, that of greater diameter may begin in the thickness of the wall 134. The portion of greater diameter may receive a support disc of a steerable blade.

Within the same row (150; 152), the tubes 142 are regularly spaced. They can be used to mount steerable blades (not shown), or adjustable, during operation of the turbomachine. These blades are commonly referred to by the acronym VSV for the English term "Variable Stator Vane". The vanes have rods pivotally mounted in the orifices 148 and in the tubes 142. Optionally, bearings ensuring the seal and limiting the friction are arranged in the orifices 148 in contact with the rods. Rings and levers control the orientation of the blades; the same ring can cause several rows.

The tubes 142 may be welded directly to the wall 134, or over thicknesses 154. These may be insulated studs, and possibly chamfered around the corresponding tube 142. The extra thicknesses 154 may also form strips whose edges optionally describe sinusoids to lighten the housing 134 while providing a sufficient receiving surface. The extra thicknesses 154 have surfaces 156 oriented radially outwardly. Each of them surrounds the associated orifice 148. Each radial surface 156 is outside the associated orifice 148. Each orifice 148 has an edge forming its periphery. The radial surface 156 surrounds the edge of the orifice 148 and is disposed on the same radial face of the wall 134.

One or each tube 142 includes an outer wall that surrounds an inner space. This internal space extends, increases, the associated orifice 148. The tube 142 is outside the orifice 148. The depth of its empty space is added radially to the depth of the orifice 148 formed through the wall 134. A tube 142 forms a sleeve, a bearing, a sleeve , a sheath, or an extension. At least one or each tube 142 may be of constant section. A tube 142 may also show a variable section, for example that widens towards the wall 134; either inward. A tube 142 may show a frustoconical outer surface, an ellipse profile, or a cam profile. Its inner surface may be cylindrical to provide a pivot connection. Its partition can be of varying thickness.

Figure 4 shows a diagram of the process of manufacturing a housing. It may be the casing shown in Figure 2 or that in Figure 3.

The method comprises the following steps; optionally performed in the following order: (a) providing or producing 200 an arcuate wall with an orifice and a surface surrounding the orifice which is radially oriented; (b) welding 202 a tube against the radial surface and in the radial extension of the orifice; (c) 204 housing finishes. The step (a) supply or realization 200 of an arcuate wall may comprise the following intermediate phases: (a1) supply or realization of a crankcase 206. The crankcase can be obtained by hot forging, and / or by bending, to produce a straight or substantially truncated tube. Its gross wall encloses in its thickness the wall and the fixing flanges of the finished casing. (a2) Machining of the crankcase 208. This phase can be performed by turning and / or milling. It makes it possible to form the final wall by forming the raw wall, to form therein the thicknesses on which the tubes are welded, and to define the upstream and downstream radial fixing flanges. (a3) piercing the wall 210, to form the holes through the wall. It is also possible to drill the radial fastening flanges to make fixing holes. Step (b) welding 202 may comprise the following intermediate phases: (b1) supply or construction of a tube 212; then (b2) frictionally welding the tube to the wall 214 so as to radially extend the orifice. The casing then becomes a monobloc assembly.

The phase (b1) founiture or embodiment 212 may be a cut of an axial segment of a tube. It may also be the embodiment of the tube by additive manufacturing, which makes it possible to produce a tube of complex geometry. In particular, this favors the realization of a group of tubes in the same block of material. Said tubes can be joined at their touching partitions. Platelet shapes can bind the tubes together.

Additive manufacturing is in layers, it implements the metal pouch, for example titanium. This filler material is locally melted to the previous layer to complete it. The energy source used for the melting of the metal is advantageously an electron beam to obtain a better geometric fineness. The use of a laser is also considered.

The friction welding phase (b2) 214 may be an orbital weld where the tube is rubbed against the wall surface by circling around the associated orifice. The orbital movement allows to marry a tube to an orifice by making their voids coincide. The tube can also alternately rotate around itself in the frictional movement. The frictional movement can also be an axial movement. The extent of the extra thicknesses may correspond to the amplitude of the chosen friction movement. Step (b) welding 202 comprises the establishment of a support closing the opening. The support is temporary. It can be local and cooperate with essentially an opening, or be circular such disc, and close an annular row of openings. The support is placed opposite the tube, for example inside the wall. It takes over the radial friction welding forces that are exerted by the friction welding machine. This avoids deforming the wall which has been greatly thinned during machining. Step (c) finishes may include machining deburring friction welds. It may also include machining the studs on which the tubes are welded in order to transform them into chamfers around the tubes, this having the purpose of reducing the bulk and of lightening the crankcase. The protective removal can be done at this stage. Polishing of functional surfaces can be conducted. It allows a fixation on the treated and smooth surfaces, and / or an articulation of the rotating type. Step (c) finishes may include a check to estimate the quality of the tube welds. This control can be applied to each weld, or to a sample and rely on statistics. Repairs and alterations can be made if necessary.

The characteristics described in relation to one of the housings can also be applied to the other of the crankcase. The low pressure compressor housing may comprise rows of steerable vanes. Similarly, the process features apply to compressor housings, and vice versa.

Claims (18)

claims A method of manufacturing an axial turbomachine casing (30; 130), in particular an axial turbomachine compressor (4; 6), the casing (30; 130) comprising: an arcuate wall (34; 134) with an orifice (148), and a tube (42; 142) radially extending the orifice (148), the method comprising the steps of: (a) providing or producing (200) an arcuate wall (34; 134) with an orifice (148) and a surface (156) surrounding the radially oriented orifice (148), characterized in that the method further comprises a step (b) of welding (202) a tube (42; ) against the radial surface (156) and in the radial extension of the orifice (148). 2. Method according to claim 1, characterized in that in step (b) welding (202), the welding is friction welding, including orbital friction welding. 3. Method according to one of claims 1 to 2, characterized in that in step (a) supply or embodiment (200), the wall (34; 134) comprises an extra thickness surrounding the orifice (148) and on which the radial surface (156) is formed. 4. Method according to one of claims 1 to 3, characterized in that in step (b) welding (202), the wall (34; 134) comprises an extra thickness surrounding the tube (42; 142) and / or the or each extra thickness possibly forming an annular row of pads or an annular band of material. 5. Method according to one of claims 1 to 4, characterized in that the step (b) welding (202) comprises the establishment of a support against the wall (34; 134) opposite the tube (42; 142) which closes the opening. 6. Method according to one of claims 1 to 5, characterized in that in step (a) supply or embodiment (200), the orifice (148) is a through hole or a blind hole, and / or the orifice (148) comprises two portions superimposed radially and having different sizes. 7. Method according to one of claims 1 to 6, characterized in that in step (b) welding (202), the wall (34; 134) comprises a chamfer matching the tube (42; 142) and / or surrounding the tube (42; 142). 8. Method according to one of claims 1 to 7, characterized in that the step (b) welding (202) comprises a step (b1) manufacture (212) of the tube (42; 142) by layer additive manufacturing, especially powder-based and electron beam. 9. Method according to one of claims 1 to 8, characterized in that in step (a) supply or embodiment (200), the wall (34; 134) comprises several orifices (148), the step ( b1) manufacturing (212) the tube (42; 142) comprises producing a block of material with several tubes (42; 142), at the end of step (b) welding (202) each tube (42; 142) of the block is associated with an orifice (148) of the wall (34; 134), the block being preferably produced by layer-based, powder-based additive manufacturing, and by electron beam. 10. A turbomachine (2) comprising a casing (30; 130), characterized in that the casing (30; 130) is derived from the manufacturing method according to one of claims 1 to 9, the casing (30; 130) being formed of half-shells. 11. A turbomachine (2) according to claim 10, characterized in that it comprises a low pressure compressor (4), the housing (30) being that of the low pressure compressor (4), the tube (42; 142) being disposed axially spaced from an annular row of stator vanes (26), preferably axially between two annular rows of stator vanes (26). 12. Turbine engine (2) according to one of claims 10 to 11, characterized in that it comprises a high pressure compressor (6), the housing (130) being that of the high pressure compressor, the tube (42; 142). being disposed axially in an annular row of stator vanes. 13. The turbomachine (2) according to one of claims 10 to 12, characterized in that the orifice (148) comprises two radial portions of different diameters. 14. A turbomachine (2) according to one of claims 10 to 13, characterized in that the housing (30; 130) comprises a radial annular fixing flange (38; 138) whose radial height is less than the radial depth of the orifice (148). 15. The turbomachine (2) according to one of claims 10 to 14, characterized in that it comprises a variable-pitch blade with a rod pivotally mounted in the orifice (148) and passing through the tube (42; 142). 16. Turbomachine (2) according to one of claims 10 to 15, characterized in that it comprises an acoustic panel (40) with a fixed attachment to the orifice, in particular in contact with the tube (42). 17. Turbomachine (2) according to one of claims 10 to 16, characterized in that it comprises a duct (46) for defrosting and / or cooling with a fixed attachment to the orifice in the tube (42). 18. A turbomachine (2) according to one of claims 10 to 17, characterized in that it comprises an annular seal (44), in particular a layer of abradable material, arranged axially in line with the tube (42).