FR3053402A1 - ARRANGEMENT FOR THE FASTENING OF A THRUST INVERSION TRAP ROD ON A FIXED INTERNAL STRUCTURE OF A TURBOJET NACELLE AND ASSOCIATED MOUNTING / DISMANTLING METHOD - Google Patents

Abstract

The present invention relates to an arrangement (30) for attaching at least one thrust reverser flap (18) to a fixed internal structure (8) of a turbojet engine nacelle (1). , the arrangement (30) being characterized in that it comprises: a fixing fitting (40) comprising a connecting interface (41) with a foot (21) of the connecting rod (20), said fixing fitting (40) ) being arranged to be secured to the inner fixed structure (8), with a single mounting bracket (50), by fixing means (45); a fairing (60) to protect the connecting interface (41) from the flow with the foot (21) of the connecting rod (20) when in the assembled position, the fairing (60) and the mounting bracket (50) each comprising complementary cooperation means (55, 65) for engaging one with the other; locking means (70) for locking the engaged position of the fairing (60) relative to the mounting bracket (50); and at least one stabilizing seal (80) carried by the shroud (60) and arranged to contact and abut against the fixed structure (8) in the assembled position; the locking means (70) being opposite the seal (80) with respect to the connecting interface (41).

Description

(57) The present invention relates to an arrangement (30) for fixing at least one connecting rod (20) of flap (18) for thrust reversal on a fixed internal structure (8) of a nacelle (1 ) of a turbojet engine, the arrangement (30) being characterized in that it comprises: a fixing fitting (40) comprising a connection interface (41) with a foot (21) of the connecting rod (20), said fitting fixing (40) being arranged to be secured to the internal fixed structure (8), with a single fixing support (50), by fixing means (45); a fairing (60) to protect the connection interface (41) with the foot (21) of the connecting rod (20) when it is in the assembled position, the fairing (60) and the fixing support (50) each comprising complementary means of cooperation (55, 65) for engaging with each other; locking means (70) for locking the engaged position of the fairing (60) relative to the fixing support (50); and at least one stabilization joint (80) carried by the fairing (60) and arranged to be in contact and in abutment against the fixed structure (8), in the assembled position; the locking means (70) being opposite the seal (80) relative to the connection interface (41).

i

Arrangement for fixing a thrust reverser flap connecting rod on a fixed internal structure of a turbojet engine nacelle and associated mounting / dismounting method

The present invention relates to a thrust reverser for an aircraft turbojet engine nacelle and, more specifically, to an arrangement for fixing a thrust reverser flap rod on a fixed internal structure of a turbojet engine nacelle. as well as its associated assembly and / or disassembly process.

An aircraft is powered by several turbojet engines each housed in a nacelle used to channel the air flows generated by the turbojet engine which also houses a set of actuating devices ensuring various functions when the turbojet engine is in operation or stopped.

These actuating devices can include, in particular, a mechanical thrust reversal system.

A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a middle section intended to surround a fan of the turbojet engine, a downstream section housing thrust reversing means and intended to surround the combustion chamber of the turbojet engine , and is generally terminated by an ejection nozzle, the outlet of which is located downstream of the turbojet engine.

Modern nacelles are intended to house a double-flow turbojet engine capable of generating, via the blades of the fan, a flow of air, part of which, called hot or primary flow, circulates in the combustion chamber of the turbojet engine, and of which the other part, called cold or secondary flow, flows outside the turbojet engine through an annular passage, also called a vein, formed between a fairing of the turbojet engine and an internal wall of the nacelle. The two air flows are ejected from the turbojet engine from the rear of the nacelle.

The role of a thrust reverser is, during the landing of an airplane, to improve the braking capacity of the latter by redirecting forward at least part of the thrust generated by the turbojet engine. In this phase, the inverter obstructs the stream of cold flow and directs the latter towards the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels of the aircraft.

The means used to achieve this reorientation of the cold flow vary according to the type of reverser. However, in all cases, the structure of an inverter comprises movable covers (or doors) movable between a closed position or "direct jet" in which they close this passage and an open position or "reverse jet" in which they open in the nacelle a passage intended for the diverted flow. These covers can fulfill a deflection function or simply activation of other deflection means.

In the case of a thrust reverser with grids, also known as a cascade reverser, the reorientation of the air flow is carried out by deflection grids, the hood having only a simple sliding function aiming to discover or cover these grids.

The translation of the movable cover takes place along a longitudinal axis substantially parallel to the axis of the nacelle. Thrust reversal flaps, actuated by the sliding of the cover, allow an obstruction of the cold flow stream downstream of the deflection grids, so as to optimize the reorientation of the cold flow towards the outside of the nacelle.

Such a cover can either:

be of quasi-annular shape, extending without interruption from one side to the other of a suspension pylon of the assembly formed by the turbojet engine and its nacelle, such a cover being designated by the Anglo-Saxon terms " O-duct ", by allusion to the shell shape of such a cover, or in fact comprise two half-covers each extending on a semi-circumference of the nacelle, such a cover being designated by the English words" D-duct "

The sliding of a cover between its “direct jet” and “reverse jet” positions is conventionally ensured by a plurality of actuators, of the mechanoelectric type (for example: worm screw actuated by an electric motor and displacing a nut) or hydraulic (cylinders actuated by pressurized oil). Typically, there are four or six actuators, namely respectively two or three actuators distributed on each half of the thrust reverser, on either side of the suspension pylon.

The thrust reversing flaps, integral with the sliding cover of this reverser, cooperate with connecting rods connected to the fixed internal structure of the thrust reverser. When the thrust reverser operates in direct jet, the flaps are held by the connecting rods in the extension of the internal wall of the sliding cover. When the thrust reverser operates in reverse jet, the flaps are actuated by the connecting rods so as to obstruct the secondary air circulation cavity of the turbojet engine, and thereby deflect the secondary air stream forwards, allowing to perform a thrust reversal and therefore braking of the aircraft equipped with such a reverser.

In order to minimize drag at the interface between each of the flap links and their point of attachment to the fixed structure of the thrust reverser, it is generally known to use an aerodynamic fairing.

It is for example known to use a non-structural type fairing directly fixed to the fixed structure of the thrust reverser. However, in this case, the fairing envelops the foot of the connecting rod and must include returns on either side of said fairing in order to be able to fix it on the fixed structure, which increases its bulk at the expense of its aerodynamics. Furthermore, such a fairing requires the dismantling of numerous fasteners in order to be able to remove the fairing in the event of maintenance.

It is also known to use a fairing integrated into the small end fitting. The fairing is then structural and directly supports the articulation of the connecting rod end while having a return to be able to fix it on the fixed structure. Such a solution makes it possible to optimize the number of parts but is aerodynamically less efficient and requires the dismantling of numerous fasteners in order to be able to remove the fairing in the event of maintenance.

Another solution is to integrate the small end fitting into the panel of the fixed structure. In this case, the connection is then embedded in the panel and there is then no need for aerodynamic fairing. However, such a solution requires a significant reinforcement of the panel, weakened in particular by the size of the holes made to drown the joint and its attachment fitting in the panel.

The object of the invention is to solve all or part of the aforementioned drawbacks, and in particular to propose an arrangement allowing easier assembly and disassembly of the fairing, this part being capable of being changed during the life of the aircraft, and whose access to the connecting elements of the thrust reverser flap connecting rod with its fixing fitting is facilitated, so as to be able to decouple the fixed and mobile parts of the thrust reverser, this without weakening the internal structure fixed.

Furthermore, such a fairing must be both inexpensive to manufacture and have a relatively low mass so as not to make the nacelle heavier, the lightening of the structure being an important constraint in the aeronautical field.

The aerodynamics of the arrangement must also create a minimized and relatively low drag so as not to impact the performance of the thrust of the turbojet.

In other words, the object of the invention is to propose a simpler arrangement, improved and compatible with the constraints linked to use in a nacelle of a turbojet engine for an aircraft.

To this end, the subject of the present invention is an arrangement for fixing at least one thrust reverser flap connecting rod to a fixed internal structure of a turbojet engine nacelle, the arrangement being characterized in that it includes:

a fixing fitting comprising a connection interface with a foot of the connecting rod, said fixing fitting being arranged to be secured to the internal fixed structure, with a single fixing support, by fixing means, a fairing to protect from the flow the interface for connection with the foot of the connecting rod when it is in the assembled position, the fairing and the fixing support each comprising complementary means of cooperation for engaging with each other, a locking means for locking an engaged position of the fairing relative to the fixing support, and at least one stabilization joint carried by the fairing and arranged to be in contact and in abutment against the fixed structure, in the assembled position, the locking means being positioned at the opposite of the joint with respect to the bonding interface.

Thanks to these characteristics, it is possible to connect the thrust reverser flap rod with the fixed internal structure of the nacelle in a simple and reliable manner.

Indeed, fixing the fixing fitting together with the single fixing support by the fixing means, allows the same fixing means to be used to ensure a simple and reliable connection of these elements with the IFS further allowing not to weaken the fixed internal structure significantly.

Furthermore, by using a locking means positioned opposite the joint with respect to the connection interface, this allows a configuration which is at the same time simple, practical and reliable in terms of distribution of the forces on the arrangement during its use.

The use of a single fixing support also makes it possible to simplify the fixing structure minimizing the connecting parts and therefore the volume of the arrangement, which also makes it possible to reduce the dimensions of the fairing so that it has a interior space just sufficient to protect the connection interface with the foot of the connecting rod from the flow when it is in the assembled position.

The complementary cooperation means of the fairing and of the fixing support make it possible to engage these elements together so as to facilitate the positioning of the two parts during assembly and disassembly, as well as facilitate the establishment of the locking means and its removal. In fact, these cooperation means are arranged so that in the engaged position, the fairing is kept assembled with the fixing support. During its handling, it is then not necessary for an operator to hold the fairing to install or remove the locking means.

Advantageously, the locking means is positioned upstream relative to the connection interface and the stabilization joint is positioned downstream relative to said connection interface.

By using on the one hand, a locking means positioned upstream of the seal relative to the connection interface, that is to say located axially between a front wall of the fairing arranged to face the flow in the vein and the connection interface and using, on the other hand, a stabilization joint positioned downstream relative to said connection interface, that is to say located axially between a rear end of the fairing, axially opposite to the wall front, and the connection interface, this allows a configuration that is both simple, practical and not very bulky, making it possible to reduce its bulk and, consequently, to reduce the wet surface of the fairing in contact with the flow thus reducing the drag of the flow. .

Preferably, the cooperation means are arranged so as to be situated opposite the locking means with respect to the connection interface, or downstream from said connection interface, this so as to ensure good distribution of the efforts to maintain the fairing relative to the support and minimize any means of securing the parts together.

According to a particular technical characteristic, the fixing support is in one piece. This notably guarantees a reduced volume and weight while providing improved structural strength. Of course, local reinforcements can be complementary such as an insert to receive the locking means.

According to a particular technical characteristic, the locking means is unique. This locking means may for example be a connecting screw which is screwed directly into the fixing support or else screwed into a threaded insert in order to locally reinforce the fixing support at the level of the locking means, the connecting screw passing through at least partly the mounting bracket. Alternatively, a cage-nut can be envisaged to receive the connecting screw passing through the fixing support.

Advantageously, the number of fixing means is equal to two. Indeed, two fixing means are sufficient to ensure the good mechanical strength of the fixing fitting with a minimum of fixing means to reduce the bulk and the weight, while also blocking and preventing any rotation or pivoting of the fitting. fixing on itself when it is requested.

According to an advantageous technical characteristic, the fixing means, the locking means and the connection interface are aligned axially, in particular along an axis substantially parallel to a longitudinal axis of the nacelle when the arrangement is put in place on the nacelle .

Advantageously also, the stabilization joint has at least one support against the fixed internal structure which extends transversely on either side of a longitudinal central axis of the arrangement, and preferably two supports located on either side other from the mounting bracket.

According to another characteristic, the fairing comprises at least one lateral access opening to allow access from the outside to the connection interface of the fixing fitting without dismantling the fairing.

More preferably, the fairing laterally includes bulges locally forming a lateral enlargement of its base, preferably located under the lateral access openings. This improves the stability and aerodynamics of the fairing.

Advantageously, a cross section of the fairing forming an obstacle to the flow of the flow is less than 150% of a cross section of an envelope of the connection interface and preferably still less than 135%.

Preferably, the fairing is made of thermoplastic material (s). This makes it possible to offer a material which is simple to use for manufacturing such a fairing, resistant and which is relatively light.

The present invention also relates to a method of mounting, or dismounting, an assembly of at least one connecting rod of thrust reverser flap on a fixed internal structure of a nacelle of a turbojet engine according to any one aforementioned characteristics, the method being remarkable in that it comprises the following stages:

installation of fixing means for fixing the fixing fitting together with the fixing support, installation of the fairing so as to come and accommodate in its internal space at least the connection interface, then displacement of the fairing to engage the fairing on the fixing support with their complementary cooperation means, and installation of the locking means to lock the fairing to the fixing support, or vice versa, in the case of dismantling.

More precisely, in the case of dismantling, the steps of the process are as follows:

removal of the locking means to unlock the fairing of the fixing support, displacement of the fairing to disengage the fairing of the fixing support then removal of the fairing, and removal of the fixing means to separate the fixing support from the fixing fitting.

Of course, in the case of a maintenance operation intervening on the connection of the foot of the connecting rod with the fixed structure, the simple removal of the fairing is sufficient and it is not necessary to remove the fixing means to separate the support. fixing bracket. Only the locking means can then be removed, then put back once the maintenance operation is finished, which is relatively simple for the operator. Such an operation on the fixing fitting is however a relatively marginal case in the context of conventional maintenance.

Other characteristics and advantages of the present invention will become apparent in the light of the description which follows, and on examination of the attached figures, in which:

FIG. 1 is a general representation of a turbojet engine nacelle for an aircraft;

FIG. 2 illustrates a perspective view of part of a downstream section of a nacelle;

FIG. 3 illustrates a view in axial section of a thrust reverser with grids according to the prior art shown in the direct jet position;

Figure 4 is a view similar to that of Figure 1, the inverter being shown in the reverse jet position;

FIG. 5 illustrates a view in partial axial section of an arrangement for fixing a connecting rod of a thrust reverser flap on a fixed internal structure of a nacelle of a turbojet engine according to one embodiment;

FIG. 6 illustrates a perspective view of an arrangement according to this same embodiment, in a position assembled on a fixed internal structure;

FIGS. 8A and 8B illustrate exploded perspective views of this arrangement according to this embodiment in two distinct positions of a method for dismantling an arrangement according to this embodiment.

In all of these figures, identical or analogous references designate identical or analogous organs or assemblies of organs.

An XYZ coordinate system has been placed on all of these figures, the three axes of which respectively represent the respective longitudinal, transverse and vertical directions of the nacelle. Note that the arrow on the X axis points upstream of the nacelle, this term being understood with respect to the air flow intended to pass through the nacelle in operation.

As shown in FIG. 1, a nacelle 1 has a substantially tubular shape along a longitudinal axis X. This nacelle 1 is intended to be suspended from a pylon 2, itself fixed under a wing of an aircraft.

In general, the nacelle 1 comprises a front or upstream section 3 with an air inlet lip 4 forming an air inlet 5, a middle section 6 surrounding a fan of a turbojet engine 17 and a rear or downstream section 7. The downstream section 7 comprises a fixed internal structure 8 (IFS) surrounding the upstream part of the turbojet engine, and a fixed external structure (OFS) 9.

The IFS 8 and the OFS 9 delimit an annular vein allowing the passage of a main air flow penetrating the nacelle 1 at the level of the air inlet 5.

The nacelle 1 therefore has walls defining a space, such as the air inlet 5 or the annular vein, into which the main air flow penetrates, circulates and is ejected.

The nacelle 1 ends with an ejection nozzle 10 comprising an external module 11 and an internal module 12. The internal modules 12 and external 11 define a flow channel for a flow of hot air leaving the turbojet engine.

FIG. 2 illustrates a perspective view of part of a downstream section 7 of a nacelle 1.

Referring to FIG. 3, there is shown a thrust reverser with grids, typically comprising a cover 13 slidably mounted relative to a fixed structure, which comprises a fixed front frame 14 and the fixed internal structure 8.

As is known per se, the sliding cover and the fixed internal structure 8 define between them the annular cold air stream 15.

In normal operating mode, that is to say when cruising, the cold air circulates inside this vein 15 as indicated by the arrow 16 in FIG. 1, that is to say along the inner wall of the cover 13 and of the internal fixed structure 8. In this operating mode, this cold air 16 is added to the hot air leaving the turbojet engine 17, thus contributing to the thrust of an aircraft (not shown ).

In reverse thrust mode (see FIG. 4), the sliding cover 13 circulates towards the rear of the turbojet engine, that is to say towards the right of FIG. 2 under the effect of an actuator such as a hydraulic cylinder (not shown). This sliding has the effect of closing off the annular vein 15 by a plurality of flaps 18 distributed all around this vein, only one of them being visible in FIGS. 3 and 4, and the redirection of the flow d 'fresh air towards the front of the nacelle (see arrow 16' in Figure 4), through deflection grilles 19.

Each flap 18 is articulated on the sliding cover 13, and its movement from the position visible in FIG. 3, in which it is located in the extension of the internal wall of the sliding cover 13, towards its closed position visible at the FIG. 4, in which it is located across the cold air stream 15, is obtained under the action of a connecting rod 20 whose ends are pivotally mounted respectively on the fixed internal structure 8 and on the flap 18.

As is known, and more particularly visible in FIGS. 3 and 4, the connecting rod 20 is fixed at the level of its foot to a connection interface secured to a fixing fitting. This fixing fitting here protrudes into the annular cold air stream 15 so that it forms an obstacle appreciably disturbing the flow of the cold flow 16. The fixing fitting then generally has a fairing integrated into the fitting to make it more aerodynamic and minimize drag.

Such a solution is not optimal because even if it makes it possible to optimize the number of parts, it is aerodynamically less efficient and requires the dismantling of numerous fasteners in order to be able to remove the fitting forming a fairing in the event of maintenance due to its fixing d on the one hand, by lateral returns to the fixed internal structure and, on the other hand, to the connecting rod 20 itself.

Figures 5 to 8 illustrate an embodiment of an arrangement for fixing a rod of thrust reverser flap on a fixed internal structure 8 ίο of a nacelle 1 of a turbojet engine according to one embodiment of the invention aimed at solving all or part of the technical problems of the prior art.

The arrangement 30 is adapted to allow the attachment of a rod 20 of thrust reverser flap on a fixed internal structure 8 of a nacelle 1 of a turbojet engine.

The arrangement 30 comprises a fixing fitting 40 adapted to be fixed to a panel of the fixed internal structure 8. Said fixing fitting 40 comprises a connection interface 41 with a base 21 of the connecting rod 20. Said connection interface 41 comprises in particular two projections forming a bearing adapted to receive the foot 21 of the connecting rod 20 in pivot connection forming a joint. The connection interface 41 is also in pivot connection with the fixing fitting 40.

Said fixing fitting 40 is designed to be secured to the internal fixed structure 8, with a single fixing support 50, by fixing means 45.

In particular, the fixing fitting 40 comprises a substantially cylindrical body 42 having at a lower end, a plate 43 extending transversely to the body 42, and, at an upper end, opposite the lower end, the connection interface 41 which projects from the fixed structure 8 in the cold air stream 15 in the fixed position.

The arrangement 30 is adapted so that the body 42 of the fixing fitting 40 passes through the panel of the fixed internal structure 8 over its entire thickness, the plate 43 and the fixing support 50 enclosing together on either side of said panel. of the fixed internal structure 8 in the fixed position. In other words, the panel of the fixed internal structure 8 is locally sandwiched by the plate 43 on one side and by the fixing support 50 on the other side, namely on the side of the secondary vein or vein cold flow 15. Generally, the panel of the fixed internal structure is a composite panel.

The arrangement 30 further comprises a shroud 60 made of thermoplastic material for substantially covering the connection interface 41 with the base 21 of the connecting rod 20 forming a joint and protecting it from the flow when it is in the fixed and assembled position. This fairing 60 has an aerodynamic function making it possible to cover the fixing of the foot 21 of the connecting rod 20 as well as the connection interface 41 and the support 50, this in order to minimize the drag of the flow created by the arrangement 30 forming an obstacle in the flow flowing in the cold flow vein 15.

The fairing 60 and the fixing support 50 each comprise complementary means of cooperation 55, 65 for engaging with each other, for example by embedding.

These cooperation means 55, 65 complementary to the fairing 60 and the fixing support 50 make it possible to engage these elements together so as to facilitate assembly and disassembly of the fairing 60 by an operator. Indeed, these cooperation means are arranged so that in the engaged position, the fairing 60 is kept assembled with the fixing support 50. During its handling, it is then not necessary for an operator to hold the fairing to put in place or remove a locking means 70. The locking means 70 also makes it possible to lock this engaged position of the fairing 60 relative to the fixing support 50 to avoid any separation during the use of the nacelle 1.

The arrangement 30 further comprises a stabilization joint 80 carried by the fairing 60 and arranged to be in contact and in abutment directly against the fixed structure 8, in the assembled position. In this way, and in the fixed and assembled position, the fairing 60 is not in direct contact with the fixed internal structure 8 but only in contact with the fixing support 50 with which it is locked by the locking means 70 and in contact and in abutment with the seal 80, itself in contact and in abutment against said fixed internal structure 8. This makes it possible to reduce the vibrations of the arrangement 30 during its use on the nacelle 1.

The locking means 70 is positioned opposite the seal with respect to the connection interface 41. More specifically, the locking means 70 is positioned upstream with respect to the connection interface 41 and the stabilization seal 80 is positioned downstream, in particular integrally and only downstream, with respect to said connection interface 41.

The fairing 60 has substantially a dome shape delimiting an interior space 64 adapted to accommodate the articulation of the foot 21 of the connecting rod 20 with the connection interface 41.

This internal space 64 is oriented towards the side of the fixed internal structure 8 in the assembled position so that, for the flow, the external wall of the dome is substantially the only part of the assembly licked by this flow of cold air 15, at some near leaks. Indeed, some leaks may exist such as between the fairing 60 and the panel of the fixed internal structure 8. However, these leaks are negligible and have a low impact on the induced drag.

The fairing 60 also has a front wall 66 arranged to face the flow in the vein 15 and a rear end 67, opposite the front wall 66. The front wall 66 and the rear end 67 are interconnected by walls side 68. The front wall 66 thus represents the upstream of the arrangement 30 and the rear end 67 represents the downstream of said arrangement 30. The longitudinal axis X 'of the arrangement 30 corresponds to an axis substantially parallel to the longitudinal axis X of the nacelle 1, in the assembled position and mounted on the nacelle 1 and pointing upstream of said arrangement 30.

The fairing 60 in the form of a substantially dome has an upper opening 69, opposite its base 63 which is intended to be on the side of the fixed internal structure 8 in the assembled position. This upper opening 69 is configured to be crossed by the jack 20, the opening 69 being dimensioned so as to guarantee the freedom of movement of the jack 20 (rotation around the joint) during its movement between the "direct jet" positions. and "reverse jet" of the thrust reverser.

The fairing 60 comprises on each of its side walls 68, a lateral opening 61 for access to allow access from the outside to the connection interface 41 of the fixing fitting 40. This makes it possible to facilitate maintenance operations without have to remove the fairing 60.

The fairing 60 also laterally comprises, on each of its side walls 68, a bulge 62 locally forming a lateral enlargement of its base 63 and located under the lateral openings 61 for access. This improves the stability of the fairing subjected to the cold air flow 15 in operation.

Preferably, as is the case in these FIGS. 5 to 8, the fixing means 45, the locking means 70 and the connection interface 41 are aligned axially, relative to the longitudinal axis X '. This makes it possible on the one hand to improve the stability of the fairing 60 and to homogenize the distribution of the forces between the different parts of the arrangement 30 when it is used in the nacelle.

As is particularly visible in FIG. 7, the arrangement 30 comprises a single fixing support 50 formed in one piece.

The fixing support 50 has an upstream part 51 and a downstream part 52, each having an orifice 53, 54 intended to receive a fixing means 45 for connecting said fixing support 50 with the plate 43 of the fixing fitting 40 between which the panel of the fixed internal structure 8 is placed.

These fixing means 45 are only two in number and are of the screw / nut type. Only the end of the screw is threaded here, that is to say that the rod of the screw is smooth so as to reinforce their structural strength during shear work.

Each of these screws passes through the plate 43, the panel of the IFS 8, and the fixing support 50 to fix them together.

The locking means 70 is unique here and consists of a screw 71 arranged, on the one hand, to pass through an orifice 72 of the fairing 60 located in its interior space 64, and on the other hand, to cooperate with a tapping 56 of the fixing support 50 located in the upstream part 51 of said fixing support 50.

The orifice 72 is placed in the interior space 64 of the fairing 60 while being accessible from the outside through the upper opening 69, behind the front wall 66, that is to say also in the downstream vicinity of the front wall 66.

The upstream 51 and downstream 52 parts of the fixing support 50 are connected together by a longitudinal body 57, which in the assembled position, is disposed between the two projections forming a bearing of the connection interface 41 and covers a part of the cylindrical body 42 of the fixing fitting 40. This makes it possible to ensure the centering of the fixing support 50 relative to the fixing fitting 40, in particular when the fixing means 45, the locking means 70 and the connection interface 41 are aligned.

The fixing support 50 also comprises, at its downstream part 52, a cooperation means 55 arranged to cooperate with a complementary cooperation means 65 carried by the fairing 60 in its interior space 64.

The cooperation means 55 integral with the fixing support 50, and formed in one piece with said fixing support 50, comprises a vertical projection 551 at the end of which is included a finger 552 oriented substantially longitudinally upstream of the fixing support 50 .

The cooperation means 65 of the fairing 60 is housed in the interior space 64 of said fairing 60 and comprises a passage delimited by an internal wall 652 of the fairing 60 and arranged to receive the finger 552 of the cooperation means 55 of the fixing support 50.

In particular, the interior wall 652 locally forms, downstream of the fairing, a material bridge connecting, inside 64 of the fairing 60, the side walls 68. This material bridge is at a height relative to base 63 substantially equal at the height of finger 552 and has an upper bearing surface 651 on which said finger 552 cooperates in the assembled position on the IFS 8. In fact, when the fixing fitting 40 is fixed on the IFS 8 with the support fixing 50 by the fixing means 45, the positioning of the finger 552 on the upper support surface will allow the fairing 60 to be pressed onto the IFS. In this way, and in such a position where the complementary cooperation means 55, 65 cooperate together, the fairing 60 of the arrangement 30 is kept fixed and clamped against said IFS 8, and the operator can easily lock this position with the locking means 70. The bearing surface 651 of the inner wall 652 of the fairing 60 locally has a shape substantially complementary to that of the profile of the finger 552 in order to improve cooperation.

The passage may also be formed by an orifice having a closed contour (not shown) and adapted to receive finger 552 tightly, an orifice which would also include a bearing surface 651.

The seal 80 comprises two elements, each in the form of "1", and placed symmetrically with respect to one another with respect to a vertical plane passing through the longitudinal central axis X '. The upper part of each of these elements overlaps the cooperation means 55, 65 in order to minimize the size of the arrangement 30 and projects substantially relative to the base 63 of the fairing at their lower part to come into abutment IFS 8 so that the fairing 60 is not in contact and in direct contact against said IFS 8 in the fixed position.

Such a configuration is particularly simple to implement and each of the elements of the seal 80 come from the same profile in the form of “1” on the same fairing 60. This seal 80 is here forcefully placed in the interior space 64 of the fairing 60. Gluing is not necessary here in view of this advantageous profile.

Note that the shape of this seal can vary and is not limiting. For example, the seal 80 can also have an inverted "U" shape overlapping the cooperation means 55, and substantially projecting with respect to the base 63 of the fairing to come into abutment against the IFS 8 so that the fairing 60 is not in contact and in direct support against said IFS 8 in the fixed position. In this case, the seal 80 can be kept clamped between a wall of the rear end 67 of the fairing and the internal wall 652 of the cooperation means 65.

The stabilization joint 80 has two supports 81 against the fixed internal structure 8 each of its supports being offset, and preferably here equidistant, relative to the longitudinal central axis X 'and extend transversely on either side of this axis X ′, and also on either side of the fixing support 50, in particular of its downstream part 52.

Such an arrangement has many advantages. Indeed, using on the one hand, a locking means 70 positioned upstream relative to the connection interface 41, that is to say located axially between the front wall 66 of the fairing 60, arranged to face flow in the vein, and said connection interface 41, and using, on the other hand, a stabilization joint 80 positioned downstream with respect to said connection interface 41, that is to say located axially between the rear end 67 of the fairing, opposite the front wall, and the connection interface 41, this allows a configuration which is both simple, practical and not very bulky, making it possible to reduce its bulk and, consequently, to reduce the wet surface of the fairing in contact with the flow thus reducing the drag of the flow.

Thanks to such an arrangement, and against all odds, it is also possible to reduce its longitudinal dimension, and therefore the longitudinal dimension of the fairing 60. Indeed, although it might seem that an aerodynamic profile extending longitudinally could improve the aerodynamics of the fairing inside the cold flow stream, in practice the cold flow in this stream 15 is rarely perfectly parallel with respect to the longitudinal axis X of the nacelle. Thus, the flow can have a certain incidence relative to the engine axis X, incidence which reduces the aerodynamic performance of a possible fairing which would be better profiled and more extended over the length.

To further reduce the size and the longitudinal dimension of the fairing 60, its rear end 67 is truncated, and formed by a wall that is substantially planar and transverse with respect to the longitudinal axis X '. This is all the easier to compact that the seal 80 is superimposed on the cooperation means, that is to say that they are located substantially in the same transverse plane and that it is not necessary to increase the axial length of the arrangement to take account of the seal 80. It will be noted in particular that a ratio between the axial dimension of the seal 80 and that of the fairing 60 is substantially equal to one tenth.

Preferably, the rear end 67 is longitudinally distant from the connection interface 41 by a distance substantially equal to that corresponding to the longitudinal distance separating the front wall 66 at its base 63 from said connection interface 41 .

More generally, the longitudinal distance separating the rear end 67 from the connection interface 41 is less than or equal to 130% of the longitudinal distance separating the front wall 66 at its base 63 from said connection interface 41.

This ensures a minimum size for an improved aerodynamic balance in the context of use in a secondary vein of a nacelle.

Thanks to these characteristics, even if the fairing 60 does not have a “drop of water” type shape which would be optimal in a perfectly axial flow, the fairing 60 according to the invention is itself adapted in a cold flow in a secondary vein when using the nacelle where the cold flow is not perfectly axial.

Furthermore, the arrangement according to the invention is simple to use and relatively compact, compact and light while being robust.

In addition, the reduction in the fixing means compared to the prior art makes it possible to optimize the interior space 64 covered by the fairing 60, and also to reduce its transverse dimensions.

Preferably, a cross section of the fairing 60 forming an obstacle to the flow flow is less than 150% of a cross section of an envelope of the connection interface 41 and more preferably still less than 135%.

In the embodiment illustrated in FIGS. 5 to 8, the cross section of the fairing 60 forming an obstacle to the flow flow is substantially equal to 130% of the cross section of an envelope of the connection interface 41

Figures 8A and 8B illustrate exploded perspective views of this arrangement 30 in separate positions of a disassembly process.

More specifically, in the case of dismantling the arrangement, for example during a maintenance operation, the steps of the disassembly process are as follows:

removal of the locking means 70, in particular by unscrewing the screw 71, in order to unlock the fairing 60 of the fixing support 50, displacement, here an axial translation upstream, of the fairing 60, illustrated by the arrow Fl in the figure 8A, to disengage the cooperation of the fairing with the fixing support 50 then vertical displacement, illustrated by the arrow F2 in FIG. 8B, to evacuate the fairing 60, and withdrawal of the fixing means 45 to separate the fixing support 50 from the fixing fitting 40,

Conversely, the steps for mounting the arrangement 30 are as follows:

installation of fixing means 45 for fixing together the fixing fitting 40 with the fixing support 50, installation of the fairing 60 so as to come and lodge in its internal space 64 at least the connection interface 41, then displacement of the fairing 60 to engage the fairing 60 on the fixing support 50 with their complementary cooperation means 55, 65, and fitting of the locking means 70 to lock the fairing 60 to the fixing support 50.

The invention is described in the foregoing by way of example. It is understood that a person skilled in the art is able to carry out different variant embodiments of the invention without going beyond the ambit of the invention.

Claims (10)

1. Arrangement (30) for fixing at least one connecting rod (20) of flap (18) for thrust reversal on a fixed internal structure (8) of a nacelle (1) of a turbojet engine, the arrangement ( 30) being characterized in that it comprises: a fixing fitting (40) comprising a connection interface (41) with a foot (21) of the connecting rod (20), said fixing fitting (40) being arranged to be secured to the internal fixed structure (8), with a single fixing support (50), by fixing means (45), - a fairing (60) to protect from the flow the connection interface (41) with the foot (21) of the connecting rod (20) when it is in the assembled position, the fairing (60) and the fixing support (50 ) each comprising complementary means of cooperation (55, 65) for engaging with each other, a locking means (70) for locking the engaged position of the fairing (60) relative to the fixing support (50), and - At least one stabilization joint (80) carried by the fairing (60) and arranged to be in contact and in abutment against the fixed structure (8), in the assembled position, the locking means (70) being positioned at opposite the seal (80) relative to the connection interface (41). 2. Arrangement (30) according to the preceding claim, characterized in that the locking means (70) is positioned upstream with respect to the connection interface (41) and the stabilization joint (80) is positioned downstream by with respect to said link interface (41). 3. Arrangement (30) according to one of claims 1 or 2, characterized in that the fixing support (50) is in one piece. 4. Arrangement (30) according to any one of the preceding claims, characterized in that the locking means (70) is unique, preferably of the connecting screw type. 5. Arrangement (30) according to any one of the preceding claims, characterized in that the fixing means (45), the locking means (70) and the connection interface (41) are axially aligned. 6. Arrangement (30) according to any one of the preceding claims, characterized in that the stabilization joint (80) has at least one support (81) against the fixed internal structure (8) which extends transversely from side and on the other from a longitudinal central axis of the arrangement, preferably two supports (81) located on either side of the fixing support (50). 7. Arrangement (30) according to any one of the preceding claims, characterized in that the fairing (60) comprises at least one lateral opening (61) for access to allow access from the outside to the connection interface (41) of the fixing fitting (40). 8. Arrangement (30) according to any one of the preceding claims, characterized in that the fairing (60) laterally includes bulges (62) locally forming a lateral enlargement of its base (63), preferably located under the lateral openings (61) of access. 9. Arrangement (30) according to any one of the preceding claims, characterized in that a cross section of the fairing (60) forming an obstacle to the flow flow is less than 150% of a cross section of an envelope of the link interface (41) and preferably still less than 135%. 10. Method for mounting, or dismantling, an arrangement (30) of at least one connecting rod (20) of thrust reversing flap on a fixed internal structure (8) of a nacelle (1) of a turbojet engine according to any one of the preceding claims, characterized in that it comprises the following steps: installation of fixing means (45) to fix the fixing fitting (40) together with the fixing support (50), installation of the fairing (60) so as to come and lodge in its interior space (64) at the minus the connection interface (41), then displacement of the fairing (60) to engage the fairing (60) on the fixing support (50) with their complementary means of cooperation (55, 65), and installation of the means locking (70) to lock the fairing (60) to the fixing support (50), or vice versa, in the case of disassembly. 2/5