Component for aircraft and aircraft

Abstract

The invention relates to an assembly for an aircraft and to an aircraft. In order to bring a pylon box (28) of an aircraft engine attachment pylon as close as possible to a wing box (14), the invention provides two lateral forward fasteners (42), each of which comprises: a clamp (46) fixed to the wing box (14), the clamp comprising two webs (48a, 48b), at least one of which passes through the upper spar (30) of the box (28); an upper portion (58a) of one of the two opposite lateral flanges (58) of the lower transverse rib (36c) of the box reinforcement (28); an upper portion (34a) of the associated lateral panel (34); and a pin system (66) passing through the clamp (46) and the two upper portions (34a, 58a).

Description

Technical Field

[0001] The present invention relates to the field of aircraft and more specifically to an assembly comprising an aircraft wing and an engine attachment pylon fixed below the wing. The present invention preferably relates to such an assembly for supporting a large diameter double-flow engine. An example of an assembly of this type is disclosed, for example, in document FR 2887522.

[0002] The present invention is particularly applicable to commercial aircraft. Background Art

[0003] On existing aircraft, engines, such as jet engines, are suspended under the wings by means of a complex attachment system, also referred to as "EMS" (for "engine mounting structure") or even as attachment pylons. The attachment pylons commonly used have a main structure, also referred to as a rigid structure and usually produced in the form of a box, that is to say produced in the following way: assembled from bottom and top spars connected to each other by a plurality of reinforcing transverse ribs located inside the box and at the ends of the box. These spars are arranged as bottom and top faces, while lateral panels close the box on the lateral faces. In addition, the attachment pylon is arranged in the upper part of the engine and between the engine and the wing box. This clockwise position is called "at 12 o'clock".

[0004] As is known, the main structure of these pylons is designed to allow the transmission to the wing of the static and dynamic forces generated by the engines - for example weight, thrust or even various dynamic forces, in particular those associated with failure situations such as fan blade loss (FBO, "fan blade out"), nose gear withdrawal, dynamic landings, etc.

[0005] In the attachment pylons known from the prior art, such as document FR 2887522, the transmission of forces between its main structure and the wing box is usually ensured by a set of attachments comprising a front attachment, a rear attachment and an intermediate attachment, the latter being used in particular to absorb the thrust generated by the engine. These attachments are usually placed vertically between the wing box and the main structure of the attachment pylon.

[0006] On recent engines, the diameters are becoming larger and larger. For dual-flow engines, such as jet engines, the significant bypass ratio sought leads to obtaining particularly large volumes, since an increase in the bypass ratio inevitably increases the diameter of the engine and more specifically the diameter of its fan case.

[0007] Thus, the space remaining between the wing element and the engine proves increasingly limited, provided that the clearance from the ground remains acceptable from a safety point of view. It thus becomes difficult to position the attachment pylons and the various wing attachments in this remaining vertical space, which is usually dedicated to this positioning. This difficulty is compounded by the fact that the transmitted forces also have a high intensity and require appropriate dimensions for the wing box and the primary structure. In fact, the primary structure must have dimensions sufficient to provide a mechanical strength capable of withstanding the forces transmitted from the engine to the wing element, so as to have low deformations under stress so as not to reduce the aerodynamic performance level of the propulsion system.

[0008] In the prior art, many solutions have been proposed to place the engine as close as possible to the wing element from which it is suspended and in doing so to maintain the necessary clearance from the ground.

[0009] However, these solutions must continue to evolve to accommodate ever larger fan case diameters and still meet bypass ratio requirements. Summary of the invention

[0010] In order to solve this need for improvement, the subject of the present invention is an assembly for an aircraft, comprising:

[0011] - an aircraft wing, the aircraft wing comprising a wing box;

[0012] - an engine attachment pylon arranged under the wing, the pylon comprising a main structure in the form of a pylon box having a top spar extending at least partially under the wing box and also having a bottom spar, two opposite lateral panels and at least one reinforcing internal transverse rib, the at least one reinforcing internal transverse rib comprising two opposite lateral flanges respectively fixed to the two opposite lateral panels, each lateral flange being fixed to the inner surface of its associated lateral panel, the lateral panel extending on one side of the flange in the longitudinal direction (X) of the assembly; and

[0013] - Means for fixing the main structure to which the pylon is attached to the wing box.

[0014] According to the invention, the fixing device comprises two front lateral attachments, each of these attachments comprising:

[0015] a clamp fixed to the wing box, the clamp comprising two webs, at least one of which passes through the top spar of the pylon box so as to be located at least partially inside the pylon box;

[0016] - the upper part of the associated lateral panel;

[0017] - strengthening the upper portion of one of the two opposite lateral flanges of the internal transverse rib; and

[0018] - A pin system passing through the two webs of the clamp, the upper part of the associated lateral panel and the upper part of the lateral flanges.

[0019] By means of the proposed arrangement, the main structure of the pylon can be brought as close as possible to the wing, firstly because part of the front lateral attachments is located in the pylon box and no longer vertically superposed on it. Moreover, in the longitudinal direction, the structural continuity of the pylon box is not interrupted by the presence of the front lateral attachments, which facilitates a good absorption of the forces in the box in this longitudinal direction. In addition, since the lateral flanges of the front lateral attachments are fixed to the lateral panels of the pylon box, the useful cross-sectional width of the box at these attachments proves to be advantageously larger. This advantageously leads to additional savings in mass and volume in the vertical direction, which facilitates the installation of engines of larger diameter and / or the installation of engines higher to increase the ground clearance.

[0020] The present invention preferably provides at least one of the following optional features, alone or in combination.

[0021] The reinforcing inner transverse rib is inclined so as to extend downward in a forward direction.

[0022] The reinforcing inner transverse rib is used for fixing to the engine attachment part at the bottom of the reinforcing inner transverse rib.

[0023] The top spar of the pylon box is generally planar all the way along the pylon box.

[0024] The pylon box has a cross section that is continuous all along the pylon box, the box extending in the longitudinal direction of the assembly, i.e. in the fore-aft direction, on either side of the front lateral attachment at least to the rear attachment of the device for fixing the main structure of the attachment pylon to the wing box. The pylon box thus does not have any cross-sectional discontinuity, in particular at the front lateral attachment.

[0025] The same applies to the two lateral panels of the pylon box, which are each continuous all the way along the box in the longitudinal direction without breaks or interruptions.

[0026] The wing box comprises a front spar to which are fixed two reinforcement fittings which respectively support two clamps of a front lateral attachment.

[0027] Each of the front lateral attachments is designed to allow absorption of forces applied in the longitudinal and vertical direction of the assembly, and one of the two front lateral attachments is preferably also designed to allow absorption of forces applied in the transverse direction of the assembly.

[0028] The fixing device also comprises a rear attachment part which is fixed to the rear closing rib of the pylon box and which is preferably designed so as to allow absorbing only forces applied in the vertical direction of the assembly.

[0029] The fixing device forms an isostatic force absorbing system.

[0030] Preferably, the web of the clamp passes through the top spar at a lateral cutout of the top spar, said cutout opening laterally outwardly.

[0031] Preferably, the upper portion of each lateral flange is in the form of a lug.

[0032] Preferably, said upper portion of said associated lateral panel and said upper portion of one of the two opposite lateral flanges of a transverse rib are arranged between two webs of a clamp.

[0033] Preferably, the two clamps respectively belonging to the two front lateral attachment pieces are combined into one and the same component which is produced in one piece.

[0034] Finally, an aircraft comprising at least one such assembly is also a subject of the invention.

[0035] Other advantages and characteristics of the invention will become apparent from the non-limiting detailed description that follows. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] The description will be given with reference to the accompanying drawings, in which:

[0037] - Figure 1 shows a side view of an aircraft including an assembly according to the invention;

[0038] - Figure 2 This is an enlarged side view showing the engine Figure 1 Components;

[0039] - Figure 3 It is cut along the cutting line III-III Figure 2 A cross-sectional view of the components shown in ;

[0040] - Figure 4 yes Figure 2 and Figure 3 a perspective view of a portion of the assembly shown in;

[0041] - Figure 5 is a stereogram similar to the previous one viewed from another perspective; and

[0042] - Figure 6 is a side view of the assembly shown in the preceding figure, schematically illustrating the absorption of forces performed by the device for fixing the pylon to the wing. DETAILED DESCRIPTION

[0043] Reference Figure 1 The aircraft 100 is shown to include a fuselage 3 on which two wings 2 are fixed (only one wing is Figure 1 ), each wing forms an integral part of an assembly 1 according to the invention. The assembly 1 supports a twin-flow and twin-body engine 10, such as an ultra-high bypass ratio (UHBR) jet engine. The assembly 1 comprises not only the wing 2, but also a pylon 4 for attaching the engine 10 and placed between the wing 2 and the engine.

[0044] Throughout the following description, by convention, direction X corresponds to the longitudinal direction of assembly 1 and can also be considered as the longitudinal direction of engine 10, which direction X is parallel to the longitudinal axis of the engine. In addition, direction Y corresponds to a direction oriented transversely relative to assembly 1, but can also be considered as a transverse direction of the engine. Finally, direction Z corresponds to the vertical or height direction, and these three directions X, Y and Z are mutually orthogonal. Therefore, engine 10 is suspended below assembly 1 in direction Z.

[0045] Furthermore, the terms “front” and “rear” are considered with respect to the direction in which the aircraft is advanced due to the thrust exerted by the engines 10 , which direction is schematically indicated by the arrow 7 .

[0046] Now refer to Figure 2 , shows an assembly 1, below which an engine 10 having a longitudinal axis 12 is suspended. The wing 2 of this assembly 1 has the following design as in conventional designs: the wing 2 comprises a wing box 14 extending in the span direction. The wing box 14 is formed by a front spar 16, a rear spar 17, an upper surface top skin 20 and a lower surface bottom skin 22. The two spars 16, 17 are preferably substantially parallel and extend in the span direction of the wing and are spaced apart from each other in the chord direction of the wing. Substantially longitudinal reinforcing internal ribs (not shown) may be fixed to each of the four box-shaped elements 16, 17, 20, 22 by rivets, bolts or similar elements and housed in the wing box 14. In addition, at the front of the wing box 14, the wing 2 comprises a fairing 26 forming the leading edge of the wing.

[0047] Another element of the assembly 1, namely the attachment pylon 4, comprises a main structure 28 in the form of a box. Other constituent elements of the pylon 4, not shown, of the auxiliary structural type for ensuring the separation and retention of the system and at the same time supporting the aerodynamic fairing, are conventional elements similar to those encountered in the prior art. Therefore, they will not be described in detail.

[0048] The primary structure 28 or rigid structure allows the transmission of the static and dynamic forces generated by the engine 10 to the wing box 14. The box formed by this primary structure 28 extends over the entire length of this primary structure in the direction X. This box has a conventional design, i.e. it is delimited at the top by a top spar 30, at the bottom by a bottom spar 32 and laterally by lateral panels 34. As in Figure 2 As can be observed in Figure 1 , the top spar 30 is at least partially located below the wing box 14. In this regard, it should be noted that each of the above-mentioned elements 30, 32, 34 can be made as a single component or by assembling several different components. Moreover, one and the same component can constitute all or part of several of these elements 30, 32, 34. One of the particular features of the primary structure - which is hereinafter referred to as the pylon box 28 - is that in the top spar 30, which is of substantially planar form, it is located all the way along the box in the direction X. This simplifies the pylon box 28 and allows a better absorption of the forces inside the box in the direction X.

[0049] Furthermore, the pylon box 28 is equipped with reinforcing transverse ribs, some of which are arranged approximately in the plane YZ and distributed along the X direction. These reinforcing transverse ribs are internal transverse ribs 36, reinforcing transverse ribs 36b of the rear part of the closed pylon box 28, called rear closed ribs, and reinforcing transverse ribs 36a of the front part of the closed box, called front closed ribs. The ribs 36, 36a, 36b connect the external elements of the boxes 30, 32, 34 to each other. Another reinforcing transverse rib 36c, which is peculiar to the invention, is arranged inside the pylon box. This rib 36c forms an integral part of the front lateral attachment 42 and mechanically connects these wing attachments 42 to the rear engine attachment, which will be described below. Unlike the other ribs, the rib 36c extends downward in the forward direction and preferably remains parallel to the direction Y at the same time. The angle A defined by the rib 36c and the direction Z is, for example, between 20° and 60°.

[0050] The rack box 28 has a cross section YZ in the form of a substantially square, rectangular or parallelogram extending downward in a trapezoidal form, as shown in FIG. Figure 3 As can be observed in the figure, which will be described below. This cross section tapers along the direction X, but it remains continuous all the way along the pylon box 28, which allows better absorption of the forces in this box. In other words, the cross section does not experience any kind of sudden interruption along the pylon box 28. Preferably, the cross section tapers in the forward and rearward directions from the middle part of the box including the rib 36c.

[0051] The fixing of the engine 10 to the pylon box 28 is carried out in a conventional manner, which will now be briefly described in detail. A front engine attachment 9a is provided, which connects the front closing rib 36a to the fan casing 11 of the engine or to the intermediate casing shell 11'. A rear engine attachment 9b is also provided, which connects the gas injection casing 13 of the engine to the bottom part of the pylon box 28. Preferably, the body of the rear engine attachment 9b is fixed to the bottom spar 32 and to the bottom end of the reinforcing internal transverse rib 36c to promote stronger forces between the engine and the wing. In addition, the two engine attachments 9a, 9b are supplemented by two conventional thrust absorbing links 9c, which connect the base 15 of the intermediate casing to the body of the rear engine attachment 9b.

[0052] These engine attachments 9a, 9b, 9c are produced in a conventional manner known to those skilled in the art. The engine attachments 9a, 9b, 9c together form an isostatic force absorbing system, like the means for fixing the pylon box 28 to the wing box 14, which is peculiar to the present invention and to which reference will now be made. Figures 2 to 5 Describe it.

[0053] These fastening means here comprise a rear attachment part 44 and two front lateral attachment parts 42 .

[0054] The two front lateral attachments 42 have an identical or similar design and are arranged largely symmetrically with respect to a median plane XZ of the assembly 1 , which lies between the two planes. Figure 3 Therefore, only one of the two front lateral attachments 42 will now be described.

[0055] The front lateral attachment 42 firstly comprises a clamp (clevis) 46 fixed to the wing box 14. This clamp 46 is fixed below the lower surface bottom skin 22 by conventional bolt or rivet type means. The clamp 46 comprises two parallel webs 48a, 48b, each of which is arranged in double so as to ensure a safety function in the event of a failure, a function generally referred to as "fail-safe". Each web 48a, 48b is in the plane XZ and extends rearward to the approximate middle length of the wing box 14. The flange 50 of the clamp 46 is not only fixed on the outer surface of the lower surface bottom skin 22 but also fixed on a reinforcing fitting 52 carried by the front spar 16 of the wing box. This fitting 52 is generally in the form of a bracket and is at least partially housed in the front edge region of the wing defined by the fairing 26. Therefore, two fittings 52 are provided in the form of brackets and spaced apart from each other along the front spar 16 of the wing box.

[0056] The web 48b corresponding to the outer web of the clamp is preferably located on the outside of the pylon box 28 so as to face or press against the outer surface of the lateral panel 34 associated with the attachment in question. Another web 48a corresponding to the inner web of the clamp passes through the top spar 30 of the pylon box to be positioned at least partially housed in this box 28. This web 48a is then said to be "embedded" in the pylon box 28, which makes it possible to reduce the vertical volume of the assembly 1. In this regard, it should be pointed out that the web 48a can pass through the top spar 30 at the opening of the top spar 30 defined by the closure line. However, in the embodiment described and shown, the web 48a passes through a lateral cutout 51 of this top spar 30, which is open laterally outwards. These two lateral cutouts 51 provided on both sides of the spar 30 cause the width of the spar to narrow at the front lateral attachment 42.

[0057] As an indication, it should be pointed out that the two clamps 46 can be combined into one and the same part manufactured in one piece and that the bases of the two clamps 46 fixed to the lower face bottom skin 22 form the two flanges 50 of the two clamps 46 .

[0058] Furthermore, the front lateral attachment 42 also comprises a portion of a reinforcing internal transverse rib 36c, as will be explained below. The rib 36c actually comprises a bottom flange 56 fixed to the bottom spar 32 and two opposite lateral flanges 58 fixed respectively to two opposite lateral panels 34. More specifically, each lateral flange 58 is fixed and pushed against the inner surface of its associated lateral panel 34. The flange 58 is substantially locally parallel to its associated lateral panel 34, which extends continuously in the X direction on one side of the flange, so as to better absorb the forces passing through the box 28.

[0059] A transverse web 61 joins the two lateral flanges 58 by passing through the interior of the box in the Y direction. The top portion 58a of each lateral flange 58 is in the form of an ear and is arranged to protrude upwards from the transverse web 61. This upper portion 58a is traversed by a passage hole 60 which is aligned transversely with the holes 62a, 62b of the two clamp webs 48a, 48b and with the hole 64 facing the relative lateral face 34.

[0060] The front lateral attachment 42 therefore also comprises an upper portion 58a of one of the two lateral flanges 58 of the rib 36c, forming the top end of this flange provided with the passage hole 60. The upper portion 58a of this flange is therefore also embedded in the box.

[0061] The front lateral attachment 42 also comprises the upper portion 34a of the lateral panel 34, ie that portion of this panel 34 which presses against the upper portion 58a of the corresponding flange.

[0062] As in Figure 3 As can be better seen in Fig. 4 , the upper portion 34a of the lateral panel and the upper portion 58a of the associated flange 58 are preferably arranged between the two webs 48a, 48b of the clamp 46, giving the clamp a so-called "concave" feature. It should be noted that the two upper portions 34a, 58a are preferably pressed laterally against each other, forming together one and the same force path. The redundancy ensures a "fail-safe" safety function in the event of a failure of one of the two elements 34a, 58a, without the risk of propagating damage between the two identical elements.

[0063] Finally, the attachment 42 is completed by a pin system 66 oriented transversely and passing successively through each of the holes 62a, 64, 60, 62b, the diameters of which are substantially the same. The pin system 66 performs a shear pin function and can be provided in double to meet the "fail-safe" safety standard.

[0064] More specifically refer to Figure 5 , Figure 5 The rear attachment 44 is shown, which comprises a clamp 70 fixed to the lower surface bottom skin 22 of the wing box. It should be pointed out here again that this rear clamp 70 can be combined in a single piece of the two clamps 46 forming the front lateral attachment 42. In addition, the rear attachment 44 comprises a fitting 72 fixed to the rear closing rib 36b of the pylon box 28. The rib 36b and the fitting 72 can each be provided in double to solve the "fail-safe" safety standard. In addition, a pin system 76 oriented in the Y direction passes through the clamp 70 and the fitting 72.

[0065] Now refer to Figure 6 , the manner in which the forces are absorbed using the previously described isostatic fixing means and which allows a simplified assembly of the pylon box 28 on the wing 2 will now be described. Each of the two front attachments 42 is arranged to allow the absorption of forces applied in both the X and Z directions, and one of them also ensures the absorption of forces in the Z direction. The other of the two front lateral attachments 42 does not absorb transversely directed forces under normal operating conditions, but only ensures the absorption of forces in the three directions X, Y and Z in the event of a failure of the attachment 42. The rear attachment 44, for its part, is designed to ensure the absorption of forces only in the Z direction.

[0066] Obviously, various modifications may be made by those skilled in the art to the invention which has been described merely in a non-limiting manner and the scope of the invention is defined by the appended claims.

Claims

1. A component (1) for an aircraft, the component (1) comprising: - an aircraft wing (2), the aircraft wing (2) comprising a wing box (14); - an engine attachment pylon (4) arranged below the wing (2), the pylon comprising a main structure in the form of a pylon box (28), the pylon box (28) having a top spar (30) extending at least partially below the wing box (14) and also having a bottom spar (32), two opposite lateral panels (34) and at least one reinforcing internal transverse rib (36c), the at least one reinforcing internal transverse rib (36c) comprising two opposite lateral flanges (58) respectively fixed to the two opposite lateral panels (34), each lateral flange (58) being fixed to the inner surface of the lateral panel (34) associated with the lateral flange (58), the associated lateral panel (34) extending on one side of the flange in the longitudinal direction (X) of the assembly; as well as - fixing means (40, 42) for fixing the main structure (28) of the attachment pylon to the wing box (14), Characterized in that the fixing device comprises two front lateral attachments (42), each of which comprises: a clamp (46) fixed to the wing box (14), the clamp comprising two webs (48a, 48b), at least one of the two webs (48a, 48b) passing through the top spar (30) of the pylon box (28) to be at least partially located inside the pylon box; - an upper portion (34a) of said associated lateral panel (34); - an upper portion (58a) of one of the two opposite lateral flanges (58) of the reinforcing internal transverse rib (36c); and - a pin system (66) passing through the two webs (48a, 48b) of the clamp (46), the upper portion (34a) of the associated lateral panel (34) and the upper portion (58a) of the lateral flange (58).

2. The assembly according to claim 1, wherein The reinforcing inner transverse rib (36c) is inclined to extend downward in the forward direction.

3. The assembly according to claim 1, wherein: The reinforcing inner transverse rib (36c) is used to be fixed to the engine attachment (9b) at the bottom of the reinforcing inner transverse rib.

4. The assembly according to claim 1, characterized in that The top spar (30) of the pylon box (28) is generally planar along the pylon box.

5. The assembly according to claim 1, wherein: The pylon box (28) has a cross section that is continuous along the pylon box.

6. The assembly according to claim 1, wherein: The wing box (14) comprises a front spar (16) on which two reinforcement fittings (52) are fixed, the two reinforcement fittings (52) respectively supporting the two clamps (46) of the front lateral attachment (42).

7. The assembly according to claim 1, wherein: Each of the front lateral attachments (42) is designed to allow the absorption of forces applied in the longitudinal direction (X) and in the vertical direction (Z) of the assembly.

8. The assembly according to claim 7, wherein: One of the two front lateral attachments (42) is also designed to allow the absorption of forces applied in the transverse direction (Y) of the assembly.

9. The assembly of claim 1, wherein: The fixing device also includes a rear attachment member (44) fixed to a rear closing rib (36b) of the rack box (28).

10. The assembly according to claim 9, wherein: The rear attachment (44) is designed to allow the absorption of forces only applied in the vertical direction (Z) of the assembly.

11. The assembly according to claim 1, wherein: The fixing device forms an isostatic force absorbing system.

12. The assembly of claim 1, wherein: The web (48a) passes through the top spar (30) at a lateral cutout (51) of the top spar (30), the cutout being laterally open outward.

13. The assembly of claim 1, wherein: The upper portion (58a) of each lateral flange (58) is in the form of an ear.

14. The assembly of claim 1, wherein: The upper portion (34a) of the associated lateral panel (34) and the upper portion (58a) of one of the two opposing lateral flanges (58) of the transverse rib are disposed between the two webs (48a, 48b) of the clamp (46).

15. The assembly of claim 1, wherein: The two clamps (46), respectively belonging to the two front lateral attachments (42), are combined into one and the same component produced in one piece.

16. An aircraft (100) comprising at least one assembly (1) according to claim 1.

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