THRUST REVERSER COMPRISING AT LEAST ONE DEPLOYABLE DEFLECTING MEMBRANE HAVING A DESIGN FACILITATING MAINTENANCE

Abstract

The invention relates to a thrust reverser for an aircraft propulsion unit, the reverser comprising two membrane support frames (60, 70) and a membrane support rod (66) connected at its ends to the frames by two mechanical links (67, 69), and a deployable deflection membrane (32), the reverser being configured so that in a mounted state of the first mechanical link (67) and in a dismounted state of the second mechanical link (69), the support rod (66) can be brought into a maintenance configuration in which the second rod end (66b) is further away from the second membrane support frame (60) than in the nominal configuration, in order to allow relative movement of the membrane along the rod for its disengagement therefrom, by the second rod end (66b). Figure for abstract: Fig. 8

Description

Title of the invention: THRUST REVERSER COMPRISING AT LEAST ONE DEPLOYABLE DEFLECTING MEMBRANE HAVING A DESIGN FACILITATING THE MAINTENANCE Technical field

[0001] The invention relates to the field of nacelles and thrust reversers for aircraft propulsion systems, and, more particularly, to thrust reversers equipped with deployable membranes to generate the flow reverser. State of the prior art

[0002] Thrust reversers are devices for diverting the airflow passing through the propulsion unit forward, so as to shorten landing distances and limit the stress on the brakes on the landing gear.

[0003] The grid reversers currently used in the aeronautical sector comprise deflection grids integrated into a fixed or mobile structure of the reverser. The mobile structure of the reverser comprises one or more mobile reverser cowls, and it is mounted so as to be movable in translation relative to the fixed structure between a forward direct thrust position and a rearward thrust reversal position.

[0004] In the rearward thrust reversal position, to divert at least part of the secondary flow towards the grilles, the reverser is usually equipped with shutters, which, when deployed, at least partially close the secondary vein. In a known manner, this forces the air of the secondary flow radially outwards, towards the grilles, which then generate the counter-thrust air flow towards the front.

[0005] The flaps are generally pivotally mounted on the radially inner wall of the movable reverser cowls, this wall delimiting the secondary flow radially outwards. Thus, recesses are provided in this radially inner wall of the reverser cowls in order to receive the shutter flaps in the retracted position, as adopted in direct jet. However, in direct jet, the presence of the recesses and the flaps is a source of aerodynamic disturbances on the secondary flow. In addition, this presence locally limits the installation of an acoustic panel on the radially inner wall of the reverser cowls.

[0006] To provide a technical solution to these problems, it has been proposed to replace the shutters with one or more deployable membranes for closing the se- secondary. Such a design is for example known from document FR 3 076 864 Al.

[0007] If the presence of deployable sealing membranes in the secondary vein makes it possible to limit the overall mass of the inverter, this remains impacted by the presence of the deflection grilles. These grilles in fact incorporate fins / vanes intended to straighten the flow forward to obtain the counter-thrust function. The radial height of these deflection fins being limited by the need to house the deflection grilles inside the inverter in direct jet configuration, it is sometimes necessary to increase the axial length of these grilles, in order to have the sufficient number of fins necessary to obtain the required counter-thrust performance.

[0008] This increase in the length of the deflection grids generates an increase in the length of several components of the inverter, such as the movable inverter cover(s), actuators, etc. This inevitably leads to a greater mass of the inverter as well as greater drag, synonymous with an increase in specific consumption.

[0009] To address this problem, it has been proposed to replace all or part of the grids with one or more deployable deflection membranes, designed to deflect at least part of the secondary flow escaping from the radial extraction opening, when this deflection membrane is in a deployed configuration adopted when the mobile structure is in the retracted thrust reversal position. However, the solutions provided prove to be improvable in terms of maintenance, in particular with regard to the ease of replacing the membranes during the lifetime of the reverser. Statement of the invention

[0010] To at least partially solve the problem mentioned above, the invention firstly relates to a thrust reverser for an aircraft propulsion unit, the reverser comprising a fixed structure equipped with a radially internal delimiting wall of a secondary vein of the propulsion unit intended to be crossed by a secondary flow, the reverser also comprising a movable structure comprising at least one movable reverser cowl equipped with a radially internal reverser cowl wall delimiting the secondary vein radially outwards, the movable structure being movable in translation relative to the fixed structure along a longitudinal central axis of the reverser, between an advanced direct thrust position, and a retracted thrust reversal position in which the movable structure and the fixed structure define axially between them, on the secondary vein,a radial extraction opening for at least part of the secondary flow, the thrust reverser also comprising at least one deployable membrane of, deflection designed to deflect at least part of the secondary flow escaping from the radial extraction opening, when this deflection or obstruction membrane is in a deployed configuration adopted when the mobile structure is in the rearward thrust reversal position,

[0011] the inverter comprising a first membrane support frame as well as a second membrane support frame corresponding respectively to front and rear frames, or vice versa, and a membrane support connecting rod comprising a first end mounted on the first support frame via a first mechanical connection, and a second end mounted on the second support frame via a second mechanical connection,

[0012] the deployable deflection membrane defining an air inlet opening in the membrane, delimited by an opening contour comprising a lateral portion of opening contour engaged on the support rod to ensure retention of the membrane when the rod is in a nominal configuration, in which the two mechanical connections are in a mounted state.

[0013] According to the invention, the inverter is configured so that in a mounted state of the first mechanical connection and in a dismounted state of the second mechanical connection, the support rod can be brought into a maintenance configuration in which the second rod end is further away from the second membrane support frame than in the nominal configuration, in order to allow relative movement of the lateral portion of the opening contour along the rod for its disengagement therefrom, by the second rod end.

[0014] The invention advantageously provides a simple, reliable solution, facilitating the operations of dismantling the deflection membrane during maintenance, for its inspection, repair, or even replacement. Indeed, the removable mounting of the membrane support rod allows its second end to be released, to then bring this rod into its maintenance configuration allowing the relative movement of the lateral portion of the opening contour along the rod, for its disengagement from the latter by the second end of the rod.Therefore, it is intended to hold the connecting rod in place on the first support frame via the first mechanical connection, then for example to orient it differently to bring it into its maintenance configuration by pivoting it around the first mechanical connection, before sliding the lateral portion of the opening contour of the membrane along the connecting rod, and thus allowing the extraction of the membrane.

[0015] The invention also allows simplified assembly of the membrane, for example when replacing it or after an inspection or repair carried out outside the inverter, by implementing the same operations, but in the reverse order.

[0016] Maintenance times and costs are thus advantageously reduced.

[0017] Furthermore, it is noted that the invention is the result of technological research aimed at significantly improving the performance of aircraft and, in this sense, contributes to reducing the environmental impact of aircraft (decarbonization).

[0018] The invention preferably provides at least one of the following optional technical features, taken alone or in combination.

[0019] Preferably, the lateral portion of the opening contour forms a retaining hem of the membrane, into which the support rod is inserted, or the support rod defines a longitudinal rail into which the lateral portion of the opening contour is inserted. Other removable connections are possible between the support rod and the lateral portion of the opening contour of the membrane, in particular connections allowing engagement / disengagement of these elements by relative sliding between them, along the rod.

[0020] Preferably, in its maintenance configuration, compared to its nominal configuration, the support rod has a different orientation, and / or a reduced length. In the latter case, the support rod is preferably telescopic.

[0021] Preferably, a front end of the lateral portion of the opening contour of the membrane has a force-recovery eyelet mounted on the support rod, or on the one of the two support frames located at the front. Alternatively or simultaneously, the opening contour of the membrane also comprises a rear portion of the opening contour, preferably of straight or rounded shape, mounted on the support rod or on the one of the two support frames located at the rear, preferably using a hanger mounted on this support frame.

[0022] Preferably, the first and second mechanical connections are ball joints.

[0023] According to one possibility, the reverser comprises two adjacent deployable deflection membranes in a circumferential direction of the reverser, and each of them has a lateral opening contour portion engaged on the same support rod, each of the two lateral opening contour portions preferably having a general notched shape comprising projecting portions alternating with hollows, with the projecting portions of the two lateral opening contour portions being arranged alternately along the support rod. This solution advantageously makes it possible to reduce the number of support rods within the reverser, and therefore reduces the mass of the latter.

[0024] Preferably, the inverter comprises a plurality of deployable deflection membranes, configured to generate counter-thrust flows of different directions.

[0025] According to one possibility, the membrane comprises a main deflection portion, having a trailing edge, and a holding member such as a cable or an intermediate membrane element connects the trailing edge to the one of the two support frames located at the front.

[0026] According to one possibility, the inverter comprises another membrane support rod having a first end mounted on the first support frame via a first mechanical connection, and a second end mounted on the second support frame via a second mechanical connection,

[0027] the opening contour comprising another lateral portion of opening contour engaged on said other support rod to ensure retention of the membrane when the rod is in a nominal configuration, in which the two mechanical connections are in a mounted state.

[0028] Furthermore, the inverter is configured so that in a mounted state of the first mechanical connection and in a dismounted state of the second mechanical connection, said other support rod can be brought into a maintenance configuration in which the second rod end is further away from the second membrane support frame than in the nominal configuration, in order to allow relative movement of the lateral portion of opening contour along said other rod for its disengagement therefrom, by the second rod end.

[0029] It is noted that the two aforementioned support rods are parallel to each other, or inclined relative to each other.

[0030] The invention also relates to a nacelle for an aircraft propulsion unit, comprising at least one fan cowl, as well as a thrust reverser as described above.

[0031] Finally, the invention relates to a method for removing a deployable deflection membrane from an inverter as described above, comprising the following steps:

[0032] - maintain the first link in its mounted state and bring the second link mechanical in its disassembled state;

[0033] - bringing the support rod into a maintenance configuration in which the second connecting rod end is further away from the second membrane support frame than in the nominal configuration;

[0034] - carry out a relative displacement of the lateral portion of the opening contour of the membrane, along the connecting rod, for its disengagement from it by the second end of the connecting rod.

[0035] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below. Brief description of the drawings

[0036] The following detailed description refers to the appended drawings in which:

[0037] [Fig.l] is a schematic half-view in longitudinal section of a propulsion unit, comprising a thrust reverser shown in the direct thrust configuration; [Fig.2] is a longitudinal half-section view of the reverser equipping the propulsion assembly shown in [Fig.l], with the reverser being in the form of a preferred embodiment of the invention, and shown in the direct thrust configuration;

[0038] [Fig.3] is a longitudinal half-sectional view similar to that of the preceding figure, with the reverser shown in an intermediate configuration between the direct thrust configuration and the thrust reversal configuration;

[0039] [Fig.4] is a longitudinal half-sectional view similar to that of the preceding figure, with the reverser shown in a thrust reverser configuration;

[0040] [Fig.5] is a perspective view showing a diverter membrane of the inverter shown in the preceding figure, in a deployed configuration of the membrane;

[0041] [Fig.5A] is a side view of the membrane shown in the preceding figure;

[0042] [Fig.ôA] is a top view of a portion of the inverter, showing several deflection membranes;

[0043] [Fig.ôB] is a perspective view of the membranes shown in the preceding figure;

[0044] [Fig.7] is a perspective view of one of the deflection membranes, showing in more detail the means used to provide its support;

[0045] [Fig.7A] is a schematic top view of the membrane shown in the preceding figure;

[0046] [Fig.8] is a schematic side view of the deflection membrane, during its disengagement from the support rods, during a membrane removal method specific to the invention;

[0047] [Fig.9] is a schematic perspective view of a front part of the membrane, cooperating with a support rod of which its cooperation with the first mechanical connection is shown;

[0048] [Fig. 10] is a schematic perspective view of a front portion of the membrane, showing the cooperation of the first mechanical connection with the front support frame [Fig.l 1] is a schematic perspective view of a rear portion of the membrane, cooperating with the rear membrane support frame;

[0049] [Fig. 12] is a schematic perspective view of a rear part of the membrane, cooperating with a support rod of which its cooperation with the second mechanical connection is shown;

[0050] [Fig. 13] is a schematic top view of the membrane, with its support means shown in an alternative manner;

[0051] [Fig. 14] is a schematic perspective view of a part of the inverter, according to another preferred embodiment of the invention;

[0052] [Fig. 15] is an enlarged schematic perspective view of part of the figure previous;

[0053] [Fig. 16] is a top view of a portion of the inverter, similar to that of [Fig.6A], according to yet another preferred embodiment of the invention;

[0054] [Fig. 17] is a perspective view of a portion of the inverter, similar to that of [Fig.5], according to yet another preferred embodiment of the invention;

[0055] [Fig. 18] is a perspective view similar to [Fig.5], according to an alternative;

[0056] [Fig. 19] is a sectional view of a portion of the inverter, similar to that of the [Fig.5A], according to yet another preferred embodiment of the invention, and taken along line XIX-XIX of [Fig.20];

[0057] [Fig.20] is a top view of the part of the inverter shown in the figure previous;

[0058] [Fig.21] is a perspective view of another preferred embodiment for the co operation between the deflection membrane and its support rod; and

[0059] [Fig.22] is a schematic side view of the inverter similar to that of [Fig.8], showing yet another preferred embodiment of the invention, in which the maintenance configuration of the support rod is different. Detailed description of embodiments

[0060] [Fig.l] shows an aircraft propulsion unit 1, having a longitudinal central axis A1.

[0061] Subsequently, the terms “upstream” and “downstream” are defined relative to a general direction SI of flow of the gases through the propulsion unit 1, along the axis A1 when this unit generates direct thrust. The terms “upstream” and “downstream” could respectively be substituted by the terms “front” and “rear”, with the same meaning.

[0062] The propulsion unit 1 comprises a turbomachine 2, a nacelle 3 as well as a mast (not shown), intended to connect the propulsion unit 1 to a wing (not shown) of the aircraft.

[0063] The turbomachine 2 is in this example a double-flow, double-spool turbojet engine comprising, from front to rear, a fan 5, a low-pressure compressor 6, a high-pressure compressor 7, a combustion chamber 8, a high-pressure turbine 9 and a low-pressure turbine 10. The compressors 6 and 7, the combustion chamber 8 and the turbines 9 and 10 form a gas generator. The turbojet engine 2 is provided with a fan casing 11 connected to the gas generator by structural arms 12.

[0064] The nacelle 3 comprises a front section forming an air inlet 13, a middle section which comprises two fan cowls 14 surrounding the fan casing 11, and a rear section 15.

[0065] In operation, an air flow 20 enters the propulsion unit 1 by the air inlet 13, passes through the fan 5 and then divides into a primary flow 20A and a secondary flow 20B. The primary flow 20A flows in a primary gas circulation vein 21A passing through the gas generator. The secondary flow 20B flows in a secondary vein 21B surrounding the gas generator. The secondary vein 21B is delimited radially inwards by a fixed internal fairing which envelops the gas generator. In this example, the fixed internal fairing comprises a first section 17 belonging to the middle section 14, and a second section 18 extending rearwards from the first section 17, so as to form a part of the rear section 15. This second section 18 is an integral part of a fixed structure of a thrust reverser which will be described below. This same section will subsequently be called wall 18 of radially internal delimitation of secondary vein 21B.

[0066] Radially outwardly, the secondary vein 21B is delimited by the fan casing 11, and, in the configuration of [Fig.l], by one or more movable reverser cowls 33 forming a part of the rear section 15 of the nacelle 3, and which will be described later. More precisely, between the fan casing 11 and the reverser cowls 33, there is provided an outer shroud 40 of an intermediate casing 42, the latter comprising the aforementioned structural arms 12, the radially outer end of which is fixed to this shroud 40. The latter therefore also participates in delimiting the secondary vein 21B radially outwardly, by being located in the downstream axial extension of the fan casing 11.

[0067] The nacelle 3 therefore comprises a thrust reverser 30 (shown schematically and partially in [Fig.l]), centered on the axis A1 and comprising on the one hand a fixed structure 31 secured to the fan casing 11, and on the other hand a structure 29 movable relative to the fixed structure 31. The fixed structure 31 comprises for example a front frame 46 which connects it fixedly to the fan casing 11, preferably via a knife-edge flange assembly located downstream of the outer shroud 11. This front frame 46 contains a profiled aerodynamic part called a deflection edge 46B, which guides the flow in a reverse jet.

[0068] In this preferred embodiment, the fixed structure 31 also comprises a plurality of deployable deflection membranes 32, one of which is shown schematically in a non-deployed configuration in [Fig.l].

[0069] Furthermore, the mobile structure 29 comprises the aforementioned mobile reverser cowls 33, for example two cowls 33 each extending over an angular amplitude of approximately 180°. This configuration with two cowls 33 is particularly well suited in the case of a nacelle design in which the cowls / walls 18 are also mounted articulated, the reverser 30 then having a so-called “D-shaped” architecture, known by the Anglo-Saxon name “D-Duct”. In this architecture, the cowls 18, 33 are connected so as to open / close simultaneously. also during maintenance operations on the engine. However, other architectures are possible, such as a so-called "C-shaped" architecture, known by the Anglo-Saxon name "C-Duct", or an "O-shaped" architecture, known by the Anglo-Saxon name "O-Duct".

[0070] Each reverser cowl 33 comprises a radially external wall 50 forming an external nacelle aerodynamic surface, as well as a radially internal wall 52 participating in the delimitation of the secondary vein 21B radially outwards. This wall 52 is located in the downstream continuity of the deflection edge 46B, in the direct thrust configuration. The two walls 50, 52 define a housing 54 open axially at the upstream end of the reverser cowl 33, and in which at least a portion of the deflection membranes 32 are located in the direct thrust configuration.

[0071] [Fig.l] shows the reverser 30 in a forward thrust configuration, called “direct jet”, corresponding to a standard flight configuration. In this configuration, the cowls 33 of the mobile structure 29 are in a closed position, called the advanced thrust or “direct jet” position, in which these reverser cowls 33 are supported on the fixed structure 31, in particular on the deflection edge 46B forming an integral part of the latter. Indeed, in the direct thrust configuration, the upstream end 52A of the radially internal wall 52 of each cowl 33 is in axial support against the deflection edge 46B.

[0072] The mobile structure 29 is thus movable in translation relative to the fixed structure 31 along the axis A1 of the reverser, between the forward direct thrust position shown in [Fig.l], and a retracted thrust reversal position which will be described later. In the forward direct thrust position of the mobile structure 29, the deflection membrane(s) 32 in the folded / non-deployed configuration are arranged in the housing 54 of the reverser cowls 33, being isolated from the secondary vein 21B by the radially internal wall 52 of these sliding cowls 33. This wall 52, forming the external wall of the secondary vein, is also called an acoustic internal panel.

[0073] The direct thrust configuration is also shown in [Fig. 2], while the rearward thrust reverser position of the movable structure 29 is shown in [Fig. 4]. [Fig. 3] shows the reverser in an intermediate position between the positions of Figures 2 and 4. All of Figures 1 to 5A show a preferred embodiment of the present invention.

[0074] In [Fig. 4], it is shown that the deflection edge 46B and the upstream end of the movable cowl 33 delimit axially between them, on the secondary vein 21B, a radial extraction opening 56 of at least a portion 20B' of the secondary flow 20B. This opening 56 of the secondary vein 21B is therefore delimited upstream by the deflection edge 46B, which, in a conventional manner, flares radially outwards. going towards the rear, to delimit an air flow 20B' intended to pass through this opening 56 when the mobile system is in this rearward thrust reversal position. In other words, the deflection edge 46B, here made rigidly, gradually moves away from the axis A1 going from the front to the rear, to guide / deflect the air through the opening 56 and towards the deployable deflection membrane 32, in the thrust reversal configuration. Conversely, this opening 56 of the secondary vein 21B is in particular delimited towards the downstream by the upstream end 52A of the radially internal part 52 of the cowl 33, but also by the upstream end of the radially external wall 50 of this same cowl.

[0075] In order to force at least a portion 20B' of the secondary flow 20B towards the opening 56, the inverter 30 comprises one or more shut-off membranes 58. Subsequently, a single membrane 58 will be described, the assembly of which has, for example, an angular amplitude identical or similar to that of the assembly of deflection membranes 32 which will be described later, and which is located in the same axial and radial plane of the propulsion assembly. Thus, several circumferentially adjacent membranes 58 may be provided within the secondary vein 21B. Nevertheless, the angular extent of the shut-off membrane 58 may be greater than that of the deflection membrane 32, without departing from the scope of the invention.

[0076] The membrane 58 may be made of a material known to those skilled in the art for this type of application. For example, it may be a non-impregnated fabric, for example aramid fibers. The membrane 58 may also be made using a composite material whose matrix is particularly flexible, for example aliphatic polyurethane, which allows use under different temperature conditions, in particular lower temperatures in the case of an aliphatic polyurethane membrane than in the case of a silicone membrane. The matrix gives a low flexural recovery capacity and the behavior of the structure obtained is indeed that of a membrane.One of the major properties of this sealing membrane 58 is that it can bend in a perfectly reversible manner (elastic or by fiber sliding) with a very small radius of curvature relative to its surface, and has a very small thickness, for example of the order of 0.1 to 3 mm. For information purposes, it is observed that this membrane 58 behaves like a boat sail or a parachute / a flying wing when it is put under pressure.

[0077] A first end 58a of the sealing membrane 58 is fixed to a rear support frame 60 belonging to the fixed structure 31 and running in the circumferential direction, this frame being located in or near a rear axial end of the opening 56 and serving to support the membranes 32. Similarly, a front support frame 70 is provided, also belonging to the fixed structure 31 and traveling in the circumferential direction, this front frame 70 being located in or near a front axial end of the opening 56 and serving to support the membranes 32.

[0078] Furthermore, a second end 58b of the sealing membrane 58, opposite the first membrane end 58a, is fixed to the wall 18. It is noted that the first end 58a can be fixed to the rear of the rear support frame 60 as shown in the figures, or to the front of this same support.

[0079] To do this, connecting rods 62 may be used, a first end of each of which is mounted on the wall 18, preferably by means of a pivot or ball joint 64. This connection 64 may be made using a fitting fixed to the fixed wall 18 and cooperating with the first end of the connecting rod 62a.

[0080] The connecting rods 62 are circumferentially spaced from each other within the secondary vein 21 B, and their number can vary.

[0081] Each connecting rod 62 is designed to move from a radially projecting position in the secondary vein 21B, a position shown in [Fig. 2] and adopted when the mobile structure 29 occupies its forward direct thrust position, to a downstream folded position, shown in [Fig. 4] and adopted when the mobile structure 29 occupies its rearward thrust reversal position. In the projecting position, each connecting rod 62 can adopt a radial or substantially radial orientation relative to the axis A1, while in the folded position, each connecting rod can adopt an axial or substantially axial orientation.

[0082] The second end of each connecting rod 62, opposite the first end, can be connected directly to the second end 58b of the membrane 58. Nevertheless, other preferred solutions are retained, such as those aiming to integrate cables and / or reinforcing straps within the means for attaching the membrane 58 to its associated elements 18, 60.

[0083] It is noted that the connecting rods 62 are axially positioned so that the trajectory of their second end is tangent or substantially tangent to the inner surface of the acoustic panel 52 in its front part, or so that the trajectory is downward in the vein.

[0084] As can be seen in Figures 3 and 4, when the mobile structure 29 moves and occupies its rearward thrust reversal position at the end of this movement, the closing membrane 58 is partly in abutment against the upstream end 52A of the radially internal wall 52 of the reverser cowl, therefore corresponding to the acoustic panel. More precisely, during the rearward movement of the mobile structure 29, the membrane 58 slides on this upstream end 52A of the radially internal wall 52.

[0085] In the rearward thrust reversal position of [Fig.4], the membrane 58 is therefore in axial support downstream against the upstream end 52A. It should be noted that depending on the extent of the axial stroke of the inverter, the membrane 58 may no longer be in contact with the internal acoustic panel 52 in the fully deployed position of the inverter, where the cover 33 is in its most rearward position. The option with contact corresponds to a minimized stroke of the inverter, while the non-contact option generally corresponds to a smoother membrane shape in reverse jet, therefore more efficient from an aerodynamic point of view.

[0086] Thus, the part of the membrane 58 which is located radially outwards relative to its bearing zone on the wall 52 closes off a part of the upstream axial opening of the housing 54, while the other part located radially inwards closes off at least a part of the secondary vein 21B, thereby diverting at least a part 20B' of the secondary flow 20B towards the opening 56 in the direction of the deployable diversion membrane 32.

[0087] It is noted that the membranes 58 could be replaced by more conventional shutters, or else be provided in combination with these shutters.

[0088] The material used to produce the membrane 32 is any one of those already mentioned above, for producing the sealing membrane 58.

[0089] As mentioned previously, in this preferred embodiment, several deflection membranes 32 follow one another within the inverter in the circumferential direction, as visible in FIGS. 6A and 6B. These membranes 32 may all be identical and arranged in the same way, or else configured to generate counter-thrust flows 20B” of different directions, as has been shown diagrammatically in [Fig. 6A]. Thus, certain membranes 32 may be arranged so as to generate counter-thrust forces with a non-zero tangential component.

[0090] Each deployable deflection membrane 32 is fixed to the two support frames 60, 70, by means which are specific to the present invention and which will be described below.

[0091] A membrane support structure is here in fact essentially produced by two membrane support rods 66, for example oriented parallel to each other in the axial direction of the inverter, or substantially parallel to it, as shown in [Fig.5]. As will be detailed later, the base of the membrane 32 is mounted on the two rods 66, all along them or substantially all along them, for example using a simple hem.

[0092] A first end 66a of the connecting rod, here the front end, is mounted on the front support frame 70 by means of a first mechanical connection 67, preferably so as to form a ball joint. Similarly, a second end 66b of the connecting rod, here the rear end, is mounted on the rear support frame 70 support 60 by means of a second mechanical connection 69, preferably also a ball joint. The connections 67, 69 therefore have a removable character as well as several degrees of freedom of movement, useful for the maintenance operations which will be explained later. The first mechanical connection 67 is also shown in more detail in Figures 9 and 10, with a fitting fixed to the front frame 70 in order to support this ball joint 67, while the second mechanical connection 69 is also shown in more detail in Figures 11 and 12, with a fitting fixed to the rear frame 60 in order to also support this ball joint 69.

[0093] Still with regard to the deflection membrane 32, it comprises a main deflection portion 74, of which a concave active deflection surface 74a has a leading edge 76 fixed to the rear support frame 60, preferably using a hanger 77, also visible in [Fig. 11].

[0094] Figures 5 and 5A show that the first mechanical connection 67 is fixed to a portion of the frame 70 having a solid extension function of the deflection edge 46B, with a profiled shape located in the aerodynamic continuity of the latter. This bypass zone with a small radius of curvature makes it possible to obtain a homogeneous direction outlet jet substantially perpendicular to the leak outlet section of the main deflection portion 74 of the membrane 32, located at a trailing edge 78 thereof.

[0095] Furthermore, at the level of this trailing edge 78, it is noted that the membrane 32 can be equipped with a fabric reinforcement 83 shown in [Fig.5A], in particular to reinforce the parallelism of its radial flanks 80.

[0096] In operation, the secondary flow 20B passes through the secondary vein 21 B, and comes to abut at least in part on the deployed closure membrane 58, which forces a portion 20B' of this flow to pass through the opening 56, therefore to pass through the opening defined by the frames 70, 60 and the connecting rods 66. The flow of the portion of flow 20B' through the extraction opening 56 thus has the consequence of pressurizing the concave active deflection surface 74a, and therefore of deploying the deflection membrane 32 to its fully deployed configuration shown in FIGS. 4 and 5 and 5A.

[0097] The main deflection portion 74, and its concave active inner deflection surface 74a, have the same curved shape which makes it possible to gradually straighten the flow portion 20B' initially of radial or substantially radial orientation on leaving the opening 56, to result in a counter-thrust flow 20B” oriented forwards, for example with a significant component parallel to the axis AL. This direction of the counter-thrust flow 20B”, which can be adapted according to the needs encountered, is substantially parallel to a tangent to the trailing edge 78 of the main deflection portion 74 and its active inner deflection surface. concave 74a. The main portion 74 and its inner active surface 74a may, for example, extend in the form of an arc of a circle or the like, preferably over an angular extent of between 75 and 90°. With this first type of membrane 32, a counter-thrust function is preferably sought, so the air outlet flow 20B” used for this counter-thrust preferably has a zero tangential component. Only an axial component, along which the U-shaped frame 66 is oriented, and possibly a radial component, are present.

[0098] The membrane 32 also comprises, circumferentially on either side of its main deflection portion 74, respectively two radial flanks 80 visible in [Fig.5]. The inner surface of these two radial flanks 80 jointly delimit, with the concave active internal deflection surface 74a of the main portion 74, a channel 82 for forward deflection of the part 20B' of the secondary flow escaping from the radial extraction opening 56, to then generate the counter-thrust flow 20B”. With the presence of these radial flanks 80 which run along and are respectively mounted on the two connecting rods 66, the membrane 32 takes a general “hood” shape, the channel 82 which it delimits internally of which is of a forward-angled shape, passing from a radial or substantially radial orientation to an axial or substantially axial orientation.To do this, each axial flank 80 of the membrane 32 adopts a general triangular, almost planar shape, with one of its sides arched, following the concave shape of the active deflection surface 74a.

[0099] Referring now to Figures 7 and 7A, it is shown that at a base 108 thereof, an air inlet opening 110 is provided in the membrane, delimited by an opening contour 112. It is thus the base 108 of the membrane which forms this opening contour 112, here in the general shape of a U and shown diagrammatically in dotted lines in [Fig.7A],

[0100] The opening contour of the membrane comprises a rear portion of opening contour 112b, here of straight shape, cooperating with the hanger 77 for fixing on the rear support frame 60. According to an alternative shown in [Fig. 13], the rear portion of opening contour 112b could be rounded, the hollow of the arc of the circle oriented towards the front. According to another alternative, whatever the shape of this rear portion of opening contour 112b, it can be mounted on the rear ends of the support rods 66, without a hanger 77 then being required.

[0101] The opening contour 112 of the membrane also comprises two lateral portions of opening contour 112a, here of straight shape, following the two connecting rods 66 on which these portions 112a are respectively engaged. Each lateral portion of opening contour 112a can form a hem 114 for retaining the membrane, in which the associated support connecting rod is inserted. Indeed, the engagement between the two lateral portions of opening contour 112a and the two connecting rods 66 is provided to ensure the retention of the membrane 32 when the support rods 66 are in a nominal configuration, in which the two mechanical connections 67, 69 of each rod are in a mounted state, on their respective frames 70, 60.

[0102] In Figures 7, 9 and 10, it is shown that a front end of the lateral portion of opening contour 112a of the membrane may have a force-recovery eyelet 116. This eyelet is either mounted on the support rod 66, or, as shown in these figures, mounted on the front support frame 70, preferably via the same fitting as that allowing the fixing of the first mechanical connection 67 on this frame 70. This eyelet 116 essentially allows the axial forces exerted on the membrane 32 to be taken up.

[0103] Thanks to the design described above, the removal of the membrane 32 can be carried out in a simplified manner, as can its assembly by carrying out the same operations in reverse order.

[0104] Such removal is carried out during maintenance, to check or replace the deflection membrane 32 in place on the inverter.

[0105] To do this, for each of the two connecting rods 66, the first connection 67 is maintained in its assembled state, while the second mechanical connection 69 is brought into its disassembled state, allowing the mobility of the connecting rod 66 around the first connection.

[0106] This mobility is used to bring each support rod 66 into a maintenance configuration shown in [Fig. 8], in which each rod 66 has a different orientation compared to its nominal configuration. In the example shown in [Fig. 8], the rod 66 has been moved by rotating along a circumferential axis around the first mechanical connection 67 in the form of a ball joint. This causes the second end 66b of each rod to move radially outward and axially forward, with the advantageous consequence that this end 66b is further away from the rear support frame 60 than in the nominal configuration. This facilitates the removal of the membrane, as will be detailed later.

[0107] It is noted that the pivoting of each connecting rod 66 could alternatively be carried out around its rear end, and not its front end, without departing from the scope of the invention. In addition, the pivoting direction of the connecting rods 66 could differ, for example by performing a rotation along a radial axis around the first mechanical connection 67. This causes the second end 66b of each connecting rod to move circumferentially and axially forward, always with the advantageous consequence that this end 66b is further away from the rear support frame 60 than in the nominal configuration. Moreover, the angles of rotation of the two connecting rods 66, as well as the amplitudes of these rotations, may differ from one connecting rod to another.

[0108] The rest of the membrane removal process consists of carrying out a relative displacement of each lateral portion of opening contour 112a, along its associated connecting rod 66, for its disengagement therefrom by the second connecting rod end 66b. This step of the process, comparable to a sliding of each hem 114 along its connecting rod in the direction of the second end 66b, is also shown diagrammatically in [Fig.8] by the arrow 120.

[0109] The advantage of such an implementation lies in the fact of only having to dismantle the two second mechanical connections 69 to allow the extraction of the membrane 32, and not to dismantle its entire support structure.

[0110] Another preferred embodiment of the invention is shown in Figures 14 and 15.

[0111] In this mode, several deflection membranes 32 follow one another in the circumferential direction, but instead of each of them being supported by two support rods 66 which would be specific to it, each rod serves to fix two directly consecutive membranes 32.

[0112] Indeed, for any two membranes 32 adjacent in the circumferential direction of the inverter, each of these membranes 32 has a lateral portion of opening contour 112a engaged on the same support rod 66. To do this, each of the two lateral portions of opening contour 112a, which therefore belong respectively to the two membranes 32, has a general crenellated shape comprising projecting parts 122a alternating with hollows 122b. Thanks to this design, the projecting parts 122a of the two lateral portions of opening contour 112a are arranged alternately along the support rod 66 which is common to them. Thus, the projecting parts 122a of the lateral portion 112a of one of the two membranes 32 are arranged in the hollows 122b of the lateral portion 112a of the other of these two membranes, and vice versa.This arrangement, where the hem portions 122a of the two membranes follow one another alternately along the connecting rods 66, considerably reduces the mass of the support structure of the deflection membranes 32 of the inverter.

[0113] [Fig. 16] shows another preferred embodiment of the invention, in which not only the successive deflection membranes 32 can have different inclinations, but also, these membranes can be of different types. In this mode shown in [Fig. 16], the two uppermost membranes in the figure are of the hood type, with different inclinations. On the other hand, the lowermost membrane 32 in the figure has a different design, but still being retained in an identical or similar manner by at least one support rod 66, according to the principle specific to the invention. This membrane 32 makes it possible to locally obtain a lateral deflection of the outlet flow. of air, with a non-zero, or even significant, tangential component, possibly even having a zero axial component. In this regard, it is noted that this tangential component may be sought in order to limit air projections towards the fuselage of the aircraft, and / or in order to avoid air reinjection phenomena within the turbomachine or the adjacent turbomachine. To do this, the membrane 32 has a lateral air outlet at the level of one of the two connecting rods, and no longer an axial air outlet.

[0114] Figures 17 and 18 show yet another preferred embodiment of the invention, in which a membrane holding member 124 is provided, which connects the trailing edge 78 of this membrane to the front membrane support frame 70. In [Fig. 17], this is a cable 124, while in [Fig. 18], this is an intermediate membrane 124, forming an intermediate radial flank parallel to the radial flanks 80 and located between them. This leads to two deflection compartments being obtained circumferentially separated from each other by the intermediate membrane 124, it being nevertheless specified that several of these intermediate membranes can be implanted on the same deflection membrane 32.

[0115] Figures 19 and 20 show yet another preferred embodiment of the invention, in which the support rods 66 can have, on the different membranes 32, different inclinations according to the axial direction, in the radial plane. In the example shown in these figures, one of the membranes 32 is supported by two rods 66 parallel or substantially parallel to the axial direction of the inverter, while the other membrane 32 is supported by two rods 66 clearly inclined relative to the axial direction of the inverter, and this in the radial plane of the latter containing each rod 66, respectively.

[0116] This variation is achieved by varying, in radius, the front and / or rear attachment points of the connecting rods 66. In addition to varying the direction of the outlet flows, this arrangement also reinforces the stiffness in the structure formed by the support rods 66 and the membrane support frames 70, 60.

[0117] With reference to [Fig.21], there is shown yet another preferred embodiment of the invention, in which the support rod 66 defines a longitudinal rail 126, in which the lateral portion of opening contour 112a is inserted. For example, this may be a cooperation of the rod 128 / bolt rope 126 type, even if other rail arrangements remain possible, without departing from the scope of the invention.

[0118] Finally, [Fig.22] shows yet another preferred embodiment of the invention, in which the maintenance configuration of the support rod is different. Indeed, instead of changing its inclination, this rod 66 passes from its nominal configuration to its maintenance configuration, by reducing its length. This operation is possible for example thanks to the telescopic character of the support rod support 66, as has been shown diagrammatically in [Fig.21]. By retracting, the connecting rod 66 moves its second end 66b away from the rear membrane support frame 60, and therefore allows an axial species to be managed between them to extract the hems 114 of this membrane. Obviously, this solution for reducing the length of the connecting rod can be combined with the previous one, aimed at changing the orientation of the latter to reach the maintenance configuration.

[0119] Various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims. For example, the thrust reverser 30 may alternatively have a “C” or “O” architecture. Furthermore, the membranes specific to the invention may coexist with conventional grids within the reverser. Furthermore, all the features disclosed above, in the various preferred embodiments and their alternatives, are combinable with each other. Moreover, it is noted that in all the figures which have been described above, the elements which bear the same numerical references correspond to identical or similar elements.Finally, it is noted that the closure of the secondary vein is preferably carried out by a flexible structure, of the membrane / textile type, and / or by a rigid structure, of the classic shutter(s) type of the prior art.

Claims

1. Claims Thrust reverser (30) for an aircraft propulsion unit, the reverser comprising a fixed structure (31) equipped with a radially internal delimiting wall (18) of a secondary vein (21B) of the propulsion unit intended to be traversed by a secondary flow (20B), the reverser also comprising a movable structure (29) comprising at least one movable reverser cowl (33) equipped with a radially internal reverser cowl wall (52) delimiting the secondary vein (21B) radially outwards, the movable structure being movable in translation relative to the fixed structure along a longitudinal central axis (A1) of the reverser, between an advanced direct thrust position, and a retracted thrust reversal position in which the movable structure (29) and the fixed structure (31) define axially between them, on the secondary vein, a radial extraction opening (56) of at least a portion of the secondary flow (20B),the thrust reverser also comprising at least one deployable deflection membrane (32) designed to deflect at least a portion (20B') of the secondary flow escaping from the radial extraction opening (56), when this deflection or obstruction membrane is in a deployed configuration adopted when the mobile structure (29) is in the rearward thrust reversal position, the reverser comprising a first membrane support frame (70) as well as a second membrane support frame (60) corresponding respectively to front and rear frames, or vice versa, and a membrane support connecting rod (66) comprising a first end (66a) mounted on the first support frame (70) via a first mechanical connection (67), and a second end (66b) mounted on the second support frame (60) via a second mechanical connection (69),the deployable deflection membrane (32) defining an air inlet opening (110) in the membrane, delimited by an opening contour (112) comprising a lateral portion of opening contour (112a) engaged on the support rod (66) to ensure the retention of the membrane when the rod is in a nominal configuration, in which the two mechanical connections (67, 69) are in a mounted state, characterized in that it is configured so that in a mounted state of the first mechanical connection (67) and in a dismounted state of the second mechanical connection (69), the support rod (66) can be brought into a maintenance configuration in which the second rod end (66b) is further away from the second membrane support frame (60) than in the nominal configuration, in order to allow relative movement of the lateral opening contour portion (112a) along the rod for its disengagement therefrom, by the second rod end (66b).

2. Inverter according to claim 1, characterized in that the lateral portion of opening contour (112a) forms a hem (114) for retaining the membrane (32), in which the support rod (66) is inserted, or in that the support rod (66) defines a longitudinal rail (128) in which the lateral portion of opening contour (112a) is inserted.

3. Inverter according to claim 1 or 2, characterized in that in its maintenance configuration, compared to its nominal configuration, the support rod (66) has a different orientation, and / or a reduced length.

4. Inverter according to any one of the preceding claims, characterized in that a front end of the lateral portion of opening contour (112a) of the membrane (32) has a force-recovery eyelet (116) mounted on the support rod (66), or on that of the two support frames (60, 70) located at the front, and / or in that the opening contour (112) of the membrane also comprises a rear portion of opening contour (112b), preferably of straight or rounded shape, mounted on the support rod (66) or on that of the two support frames (60, 70) located at the rear, preferably using a hanger (77) mounted on this support frame.

5. Inverter according to any one of the preceding claims, characterized in that the first and second mechanical connections (67, 69) are ball joints.

6. Inverter according to any one of the preceding claims, characterized in that it comprises two adjacent deployable deflection membranes (32) in a circumferential direction of the inverter, and in that each of them has a lateral portion of opening contour (112a) engaged on the same support rod (66), each of the two lateral portions of opening contour (112a) preferably having a general notched shape comprising protruding portions (122a) alternating with recesses (122b), with the protruding portions (122a) of the two opening contour side portions (112a) being arranged alternately along the support rod (66).

7. Inverter according to any one of the preceding claims, characterized in that the membrane (32) comprises a main deflection portion (74), having a trailing edge (78), and in that a holding member connects the trailing edge (78) to that of the two support frames (60, 70) located at the front.

8. A reverser according to any one of the preceding claims, characterized in that the reverser comprises a further membrane support rod (66) having a first end (66a) mounted on the first support frame (70) via a first mechanical connection (67), and a second end (66b) mounted on the second support frame (60) via a second mechanical connection (69), the opening contour comprising a further lateral portion of opening contour (112a) engaged on said further support rod (66) to ensure retention of the membrane (32) when the rod (66) is in a nominal configuration, in which the two mechanical connections (67, 69) are in a mounted state, the reverser being configured so that in a mounted state of the first mechanical connection (67) and in a dismounted state of the second mechanical connection (69),said other support rod (66) can be brought into a maintenance configuration in which the second rod end (66b) is further away from the second membrane support frame (60) than in the nominal configuration, in order to allow relative movement of the lateral opening contour portion (112a) along said other rod (66) for its disengagement therefrom, by the second rod end (66b).,

9. Nacelle (3) for an aircraft propulsion unit, comprising at least one fan cowl (14), as well as a thrust reverser (30) according to any one of the preceding claims.

10. A method of removing a deployable diverter membrane (32) from a reverser according to any one of claims 1 to 8, comprising the following steps: - maintaining the first mechanical connection (67) in its mounted state and bringing the second mechanical connection (69) into its dismounted state; - bringing the support rod (66) into a maintenance configuration in which the second rod end (66b) is further away from the second membrane support frame (60) than in the nominal configuration; - carry out a relative displacement of the lateral portion of the opening contour (112a) of the membrane, along the connecting rod (66), for its disengagement from the latter by the second end of the connecting rod (66b).

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