Manufacture of an air inlet lip or an annular portion thereof comprising an opening with an inwardly curved edge

Abstract

The present invention relates to a method for manufacturing an air inlet lip, comprising: arranging a blank facing a three-dimensional forming surface of a die of a hydraulic forming tool, wherein the three-dimensional surface comprises an outer annular portion for forming an outer wall of an air inlet lip or an annular sector of an air inlet lip, wherein the outer annular portion comprises at least one open cavity protruding from the three-dimensional surface; forming an air inlet lip or an air inlet lip sector preform (60) by hydraulically forming the blank on the three-dimensional surface of the die, wherein the cross-section of the air inlet lip or the air inlet lip sector preform is The air inlet lip or the air inlet lip sector preform (60) is U-shaped, and the outer wall (61) includes at least one hollow shell (62) having an inwardly bent edge (620) and a bottom (621), and the shape of the shell corresponds to the at least one open cavity; an opening (622) is cut in each hollow shell (62), and at least the inwardly bent edge (620) is maintained to obtain the air inlet lip, and the air inlet lip includes at least one opening, and the at least one opening has an edge formed integrally with the lip or the outer wall of the sector.

Description

Technical Field

[0001] The invention relates to the manufacture of an air inlet lip of an aircraft engine cabin. Background Art

[0002] The nacelle of an aircraft engine comprises an air intake cowl which is extended at the front by a lip which has a U-shaped cross section and is open to the rear. The air intake lip has in particular the function of ensuring the aerodynamic flow of air, on the one hand, to the fan duct and, on the other hand, to the outside of the nacelle.

[0003] The air inlet lip is usually made in one piece or from several separate annular sectors which are subsequently assembled together.

[0004] The air inlet lip or the annular sector is manufactured separately by forming the metal sheet, more particularly by spin forming. Once the air inlet lip or the annular sector is manufactured, openings are usually produced by machining in the wall of the lip or sector, in particular to accommodate and fix additional components there.

[0005] Machining openings in the lip or in the wall of the annular sector after forming may cause so-called “laminar” defects, corresponding to a modification of the aerodynamic profile of the lip or sector, possibly disturbing the flow along the outer wall of the lip or of the annular sector.

[0006] Furthermore, when the additional part is fixed at the level of the opening, the fixing members used protrude on the surface of the outer wall of the lip or sector, which can also disrupt the flow along the outer wall of the lip or lip sector.

[0007] However, there is a need to produce an air intake lip or an annular sector of the air intake lip comprising one or more openings which, after forming, do not alter the aerodynamic profile of the lip or of the annular sector. Summary of the invention

[0008] To this end, the present invention proposes a method for manufacturing an air inlet lip or an annular sector of an air inlet lip, comprising:

[0009] - arranging the blank facing a three-dimensional surface of a die of a hydroforming tool, said three-dimensional surface comprising an outer annular portion for forming the outer wall of the inlet lip or an annular sector of the inlet lip, said outer annular portion comprising at least one open cavity protruding on said three-dimensional surface,

[0010] - forming the air inlet lip or air inlet lip sector by hydroforming the blank on the three-dimensional surface of the mold, the cross section of the air inlet lip or air inlet lip sector preform being U-shaped, the outer wall of the air inlet lip or air inlet lip sector preform comprising at least one hollow shell with inwardly curved edges and a bottom, the shape of the shell corresponding to the shape of the at least one open cavity,

[0011] - cutting an opening in each hollow shell, keeping at least the inwardly bent edge, to obtain an air inlet lip or an air inlet lip annular sector comprising at least one opening having an edge integrally formed with the outer wall of said lip or said sector.

[0012] Thus, thanks to the method of the invention, each opening is made of a shell formed simultaneously with the inlet lip or the inlet lip sector. Thus, when the shaping of the shell is carried out simultaneously with the shaping of the lip or the sector, the shaping of the shell does not modify the geometry and aerodynamic profile of the outer wall. Furthermore, each shell extends under the outer wall. Thus, each subsequent machining of the shell to form the opening does not affect the geometry of the outer wall and therefore the aerodynamic profile of the lip or the sector.

[0013] According to a particular feature of the method according to the invention, when cutting the opening in the one or more hollow shells, only all or part of the inwardly curved edge remains. In this case, an additional component can be fixed to the inwardly curved edge of the opening of the hollow shell, said component extending below the outer wall of the air inlet lip or of an annular sector of the air inlet lip. The additional component can in particular be an air inlet scoop.

[0014] According to another particular feature of the method according to the invention, when cutting an opening in one or more hollow shells, a portion of the bottom of the hollow shell is retained in such a way as to form a plunge in the opening, and the method further comprises fixing an additional component to the bottom of the shell, the component being present below the outer wall of the air inlet lip or of an annular sector of the air inlet lip or being flush with the outer wall of the air inlet lip or of an annular sector of the air inlet lip.

[0015] According to another particular feature of the method according to the invention, each open cavity is mounted on a removable key. This makes it possible in particular to facilitate the demoulding of the lip or annular sector preform.

[0016] The object of the present invention is also an air inlet lip or an air inlet lip annular sector with a U-shaped cross-section, the outer wall of the air inlet lip or the air inlet lip annular sector comprising one or more openings, each opening comprising an inwardly curved edge integrally formed with the outer wall and extending under the outer wall.

[0017] According to a particular feature of the air inlet lip or the air inlet lip annular sector of the invention, an additional component is fixed to the inwardly curved edge of one or more openings on the outer wall of the air inlet lip or the air inlet lip annular sector, and the component extends below the outer wall of the air inlet lip or the air inlet lip annular sector.

[0018] According to another particular feature of the air inlet lip or of the air inlet lip annular sector according to the invention, said additional component is an air inlet duct.

[0019] According to another specific feature of the air inlet lip or the air inlet lip annular sector of the present invention, one or more openings also include a recess and an additional component on the recess, and the component exists below the outer wall of the air inlet lip or the air inlet lip annular sector, or is flush with the outer wall of the air inlet lip or the air inlet lip annular sector. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flow chart showing the steps of a method for manufacturing an air intake lip according to one embodiment of the present invention,

[0021] Figure 2 is a schematic diagram of a metal plate.

[0022] Figure 3 yes Figure 1 Schematic diagram of the ring obtained after cutting of the metal plate,

[0023] Figure 4 is from Figure 3 Schematic perspective view of the truncated cone obtained by the ring,

[0024] Figure 5 is from Figure 4 Schematic perspective view of the air inlet lip blank obtained by frustum of a cone,

[0025] Figure 6 Yes Display Figure 5 Schematic perspective view of the arrangement of the blank in the hydroforming tool,

[0026] Figure 7 yes Figure 6 Schematic cross-sectional view of a hydroforming tool after closing and running,

[0027] Figure 8 It is displayed in Figure 6 and Figure 7 Hydroforming tools for Figure 5 Schematic perspective view of the demoulding of the air inlet lip preform after hydroforming of the blank,

[0028] Fig. 9 It is displayed in Figure 8 Perspective view of the opening cut in the lip preform,

[0029] Fig.10 Is shown in the cutting Fig. 9 Perspective view of the air inlet lip obtained after the opening of

[0030] Fig.11 For Fig.10A schematic cross-sectional view of the additional cover fixed to the air inlet lip,

[0031] Fig.12 For Fig.10 A schematic cross-sectional view of an additional air intake duct being fixed to the air intake lip. DETAILED DESCRIPTION

[0032] The invention is generally applied to the production of an air inlet lip or an annular sector of an air inlet lip of an aircraft engine nacelle.

[0033] Figure 1 The steps of the method according to the invention for producing an air intake lip are described.

[0034] like Figure 2 As shown, the method starts with providing a metal plate 10, for example made of aluminum alloy (step S1). The metal plate 10 can be a whole plate or a plate formed by welding and fixing multiple plates to form a large-sized metal plate from a smaller unit metal plate.

[0035] The metal plate 10 is then cut to form Figure 3 The loop 20 shown (step S2).

[0036] The thickness of the ring 20 is machined so as to obtain a constant sheet metal thickness after forming (step S3).

[0037] The ring 20 is then formed by known sheet metal rolling techniques. Figure 4 The frustum 30 is shown.

[0038] Once formed, the truncated cone 30 is preformed into a lip blank 40, for example by embossing and / or stamping, which has a general shape similar to the shape of the final lip, that is, it already has a shape such as Figure 5 The U-shaped cross section shown (step S5).

[0039] According to the invention, the final forming of the air intake lip is then performed by hydroforming or internal high pressure forming (step S6). More precisely, Figure 6 As shown, the blank 40 is arranged in a die 51 (also called a die) of a hydroforming tool 50, the die 51 comprising a three-dimensional surface 510 corresponding to the shape of the lip preform to be obtained. Figure 7As shown, the tool 51 is sealed with a cover 52. The cover 52 includes an opening 520 through which a fluid 53 under high pressure is introduced. The high pressure P of the fluid 53 applied to the blank 40 forces the blank to form the shape of the three-dimensional surface 510 of the mold 51. In the example described here, the three-dimensional surface 510 includes an outer annular portion 510a for forming the outer wall of the air inlet lip. The outer annular portion 510a includes two open cavities 511 and 512 of different geometric shapes. In the example described here, the cavity 511 is intended to allow the formation of a hollow shell for combining the cover on the air inlet lip, while the cavity 512 is intended to allow the formation of a hollow shell for combining the air outlet on the air inlet lip. The open cavities 511 and 512 are preferably mounted on removable keys 5110 and 5120, respectively.

[0040] Once the hydroforming is completed, the integrated air intake lip preform 60 has a rotational shape with a U-shaped cross section. Figure 8 As shown, the air inlet lip is then demoulded (step S7). The open cavities 511 and 512 are here mounted on removable keys 5110 and 5120, which can be removed to facilitate demoulding of the lip after hydroforming.

[0041] At this stage, the air inlet lip preform 60 already has the final geometry of the lip, in particular at the level of its outer wall 61 along which the airflow will flow. It is therefore important to maintain the aerodynamic profile of the outer wall of the lip. As shown, the air inlet lip 60 also comprises two hollow shells 62 and 63 located on its outer wall 61, formed by cavities 511 and 512 respectively. The hollow shell 62 comprises an inwardly curved edge 620 and a bottom 621 extending below the inner wall 61. Similarly, the hollow shell 63 comprises an inwardly curved edge 630 and a bottom 631 extending below the inner wall 61.

[0042] Next, an opening is cut in each of the hollow shells 62 and 63 (step S8). Fig. 9 As shown, an opening 622 is formed in the bottom 621 of the hollow shell 62, for example by machining. In the example described here, the bottom 621 is not completely removed, so that a portion 6210 is left and a recess 623 is formed corresponding to the inward curved edge 620 and the portion 6210, both of which are integrally formed with the rest of the air intake lip preform. An opening 632 is also formed in the hollow shell 63. In the example described here, the bottom 631 is completely removed, so that only the inward curved edge 630 remains.

[0043] If the bottom of the hollow shell is completely removed, all or part of the inward-turned edge is retained depending on the fixing requirements. For example, only the bottom can be removed and the entire inward-turned edge can be retained. It is also possible to remove a portion of the inward-turned edge in order to adjust the extension depth of the edge below the outer wall of the lip as required, or even to omit the entire inward-turned edge, for example on one or more sides of the hollow shell.

[0044] Thus, an air intake lip 70 of revolution shape is obtained, which is U-shaped in section and comprises an outer wall 71 forming the aerodynamic profile of the lip. The outer wall comprises two openings 710 and 711, corresponding to the openings 622 and 632 made in the lip preform 60. The opening 710 comprises a recess 7101 integral with the outer wall 71 and extending completely underneath it. The opening 711 comprises an inwardly curved edge 7110 integral with the outer wall 71 and extending completely underneath it.

[0045] In order to manufacture an air inlet lip annular sector according to the method of the invention, steps similar to those previously described, steps S1 to S8, are implemented by adapting some of them to the manufacture of the sector. For the sake of simplicity, all these steps will not be described in detail. The adaptations of the steps already described include in particular:

[0046] - cutting a ring-shaped portion in the metal sheet (adjustment of step S2);

[0047] - forming a truncated cone portion (adjustment of step S4);

[0048] - preforming an air inlet lip annular sector blank corresponding to a section of the air inlet lip blank (adjustment of step S5);

[0049] - Forming the air inlet lip annular sector preform by hydroforming, adapting the three-dimensional forming surface of the hydroforming tool, in particular the tool die, to the shape of the annular sector (adjustment in step S6).

[0050] Thus, the method of the invention makes it possible to form an air inlet lip or an air inlet lip sector comprising one or more openings, the recessed or non-recessed edges of which are integrally formed with the structure of the lip or sector.

[0051] The opening or openings may be used in particular, but not exclusively, for fixing additional components present below or flush with the outer wall of the inlet lip or of an inlet lip annular sector.

[0052] Therefore, the method of the present invention may also include fixing one or more additional components (step S9). In the example described here, Fig.11 As shown, the first additional component corresponding to the cover 80 is fixed in the opening 710. More precisely, as Fig.11As shown, the cover 80 is fixed to the recess 7101 integrally formed with the outer wall 71 by a nut-type fixing member 81. Therefore, the cover 80 is flush with the surface of the outer wall 71 of the air inlet lip 70 (the outer surface of the cover 80 is on the same plane as the surface of the outer wall 71). Therefore, the cover 80 does not interfere with the air flow F along the outer wall 71.

[0053] The second additional component, here an air inlet 90, is fixed in the opening 711. More precisely, the air inlet 90 is fixed to an inwardly curved edge 7110 formed integrally with the outer wall 71 by means of a nut-type fixing 91. Since the air inlet 90 and the fixing member 91 extend completely under the outer wall, they do not interfere with the flow of the air flow F along the outer wall 71.

[0054] Furthermore, the presence of a fixing edge (recessed or not) integral with the lip or the outer wall of the annular sector makes it possible to fix additional components without the use of fishplates or additional mating surfaces. In this way, the overall weight of the air inlet lip is reduced.

Claims

1. A method for manufacturing a fixed air inlet lip (70) or a fixed air inlet lip annular sector, comprising: - arranging the blank (40) facing a three-dimensional surface (510) of a die of a hydroforming tool (51), said three-dimensional surface comprising an outer annular portion (510a) for forming an outer wall of a fixed air inlet lip or an annular sector of a fixed air inlet lip, said outer annular portion comprising at least one open cavity (511) protruding on said three-dimensional surface, - forming a fixed air inlet lip or a fixed air inlet lip sector preform (60) by hydroforming the blank on the three-dimensional surface of the mold, the cross-section of the fixed air inlet lip or the fixed air inlet lip sector preform being U-shaped, the outer wall (61) of the fixed air inlet lip or the fixed air inlet lip sector preform (60) comprising at least one hollow shell (62) with an inwardly curved edge (620) and a bottom (621), the shape of the hollow shell corresponding to the shape of the at least one open cavity (511), - cutting an opening (622) in each hollow shell (62), maintaining at least the inwardly curved edge (620) to obtain a fixed air inlet lip (70) or a fixed air inlet lip annular sector, the fixed air inlet lip or the fixed air inlet lip annular sector comprising at least one opening (710) having an inwardly curved edge formed integrally with the outer wall (71) of the lip or the sector.

2. The method according to claim 1, wherein: When cutting openings in one or more hollow shells, only all or part of the inturned edges remain.

3. The method according to claim 2, wherein: The additional component is fixed to the inwardly curved edge of the opening of the hollow shell, the additional component extending below the fixed air inlet lip (70) or the outer wall (71) of the fixed air inlet lip annular sector.

4. The method according to claim 3, wherein: The additional component is an air intake duct (90).

5. The method according to claim 1, wherein: When cutting an opening (622) in one or more hollow shells (62), a portion (6210) of the bottom (621) of the hollow shell is retained in such a way as to form a recess (623) in the opening, and the method further comprises fixing an additional component to the portion (6210) of the bottom of the hollow shell, the additional component being present below or flush with the outer wall (71) of the fixed air inlet lip (70) or the fixed air inlet lip annular sector.

6. The method according to any one of claims 1 to 5, wherein: Each open cavity (511) is mounted on a removable key (5110).

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