THRUST REVERSER INCLUDING AN IMPROVED STORAGE AND DEPLOYMENT SHUTTER MEMBRANE

Abstract

The invention relates to a thrust reverser (30) for an aircraft propulsion system, the reverser comprising a fixed structure (31), a movable structure (29), a deployable deflection grid (32), a sealing membrane (58), and an actuator (80). According to the invention, the sealing membrane (58) has a passage through which the actuator (80) passes, the passage being configured to allow displacement of the membrane (58) relative to the actuator (80) along the passage when the movable structure (29) moves from its forward direct thrust position to its rearward thrust reversing position. Figure for the abstract: Fig. 3

Description

Title of the invention: Thrust reverser comprising a sealing membrane IMPROVED STORAGE AND DEPLOYMENT 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 on the one hand with deflection devices to generate the reversal of the flow, and on the other hand with one or more deployable membranes for closing the secondary vein. Prior art

[0002] Thrust reversers are devices that allow the airflow through the propulsion assembly to be diverted forward, in order to shorten landing distances and limit the stress on the brakes on the landers.

[0003] The grid-type reversers currently used in the aeronautical sector include deflection grids integrated into a fixed or movable structure of the reverser. The movable structure of the reverser comprises one or more movable reverser hoods, and it is mounted to be movable in translation relative to the fixed structure between an advanced position for direct thrust and a rearward position for thrust reversal.

[0004] In the thrust reversing position, to deflect at least part of the secondary flow towards the grilles, the reverser is usually equipped with shutters which, when deployed, at least partially block the secondary flow. In a known manner, this forces the air of the secondary flow radially outwards, towards the grilles, which then generate the forward counter-thrust airflow.

[0005] The flaps are generally pivotally mounted on the radially internal wall of the movable inverter covers, this wall delimiting the secondary stream radially outwards. Thus, recesses are provided in this radially internal wall of the inverter covers to receive the shut-off flaps in the retracted position, as adopted in direct jet operation.

[0006] In the prior art, it has already been proposed to replace the flaps with one or more deployable membranes for obturating the secondary vein. Such a design is, for example, known from document FR 3 076 864 AL

[0007] While the presence of deployable obturation membranes in the secondary vein helps to limit the overall mass of the inverter, this mass remains impacted by the The presence of deflection grilles. These grilles incorporate vanes / blades designed to direct the flow forward to achieve the counter-thrust function. Since the radial height of these deflection vanes is limited by the need to house the deflection grilles inside the inverter in a direct jet configuration, it is sometimes necessary to increase the axial length of these grilles to provide a sufficient number of vanes for the required counter-thrust performance.

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

[0009] To address this issue, it is possible to provide deployable deflection grids, i.e., having a smaller axial footprint in the direct thrust configuration than in the thrust reversal configuration. This could be a telescopic deflection grid, known for example from document FR 2 947 869 A1.

[0010] While reducing the length of the housing provided in the movable cowling to receive the grid in its folded, inactive position offers an advantage in terms of the overall mass of the reverser and drag reduction, it can conversely complicate the storage and deployment of the secondary flow shut-off membrane in this same housing. This problem is all the more significant when the radial dimension of the secondary flow is large, as this implies a longer membrane. However, since increasing the thickness of the secondary flow is a current trend in order to limit fuel consumption, it can prove complex to design a reverser that integrates both a deployable deflection grid and a deployable secondary flow shut-off membrane.

[0011] Finally, it is noted that this problem is indeed encountered for flow deflection devices in the form of deployable devices, such as deployable finned deflection grids, but also in the form of fixed devices, such as fixed grids. It is also encountered for flow deflection devices in the form of deployable membranes. Description of the invention

[0012] To address at least partially the aforementioned drawback, the invention first relates to a thrust reverser for an aircraft propulsion system, the reverser comprising a fixed structure equipped with a radially internal boundary wall for a secondary flow of the propulsion system. intended to be traversed by a secondary flow, the reversing unit also comprising a movable structure including at least one movable hood having a housing open upstream and delimited between a radially external wall and a radially internal wall of the movable hood, the movable structure being displaceable in translation relative to the fixed structure along a longitudinal central axis of the reversing unit, between an advanced direct thrust position and a retracted thrust reversing position, the reversing unit also comprising a flow deflection device which is arranged, in the advanced direct thrust position of the movable structure, at least partly in the housing of the movable hood, the reversing unit also comprising a sealing membrane designed to deflect at least part of the secondary flow towards the deflection device, when the movable structure is in the retracted thrust reversing position,the sealing membrane being at least partially located within the housing of the movable cover when the movable structure is in the forward direct thrust position, and comprising a first membrane end, as well as a second membrane end connected to the radially internal boundary wall by means of attachments, the reverser also comprising an actuator fixed to the movable structure at a fixing point located downstream of the deflection device.

[0013] According to the invention, when the mobile structure is in the forward direct thrust position, the sealing membrane, the first end of which is fixed to the radially external wall of the movable hood, extends on the one hand between the radially external wall and the deflection device, and on the other hand between the radially internal wall of the movable hood and the same deflection device, bypassing it downstream, the sealing membrane having a passage through which the actuator passes, the passage being configured to allow a movement of the membrane relative to the actuator, along the passage, when the mobile structure moves from its forward direct thrust position to its rearward thrust reversal position.

[0014] The invention thus provides a simple, reliable and efficient solution for combining, within the inverter, both a deflection device of any design, and a deployable membrane for closing the secondary vein. To achieve this, the sealing membrane is arranged on either side of the deflection device, bypassing it downstream, so that the membrane can be stored properly along its entire length, which is usually considerably longer than the deflection device when folded, in the case of a deployable design. This particular arrangement is combined with the presence of a passage through the sealing membrane, which cleverly allows the actuator passing through it to extend downstream, while also permitting relative movement between the actuator and the membrane during the opening and closing phases. of the inverter. This facilitates storage and reliable deployment of the sealing membrane.

[0015] Furthermore, the combined implementation of the deflection device and the deployable membrane makes it possible to limit the overall mass and drag, thereby reducing specific fuel consumption. The invention is therefore the result of technological research aimed at significantly improving aircraft performance and, in this respect, contributes to reducing the environmental impact of aircraft (decarbonization).

[0016] The invention preferably provides for at least one of the following optional technical features, taken individually or in combination.

[0017] Preferably, the passage extends lengthwise along a main passage direction, defined between an internal radial end of the passage, and an external radial end of the passage, the latter being closed by a peripheral portion of the membrane, or else open radially outwards.

[0018] Preferably, the passage remains hollow, or at least partially sealed by an elastic leak-limiting auxiliary membrane, the elastic auxiliary membrane being configured to:

[0019] - adopt a folded position when the mobile structure occupies its forward position of direct thrust, folded position in which the elastic membrane is constrained in the direction of the internal radial end of passage;

[0020] - adopt a deployed position of at least partial closure of the passage, when the mobile structure occupies its rearward thrust reversal position;

[0021] - to unfold elastically from its folded position to its deployed position of sealing, by release of stress resulting from the displacement of the sealing membrane relative to the actuator, along the passage, during the movement of the moving structure from its advanced position of direct thrust, to its rearward position of thrust reversal.

[0022] Preferably, the flow deflection device is deployable and comprises several axially arranged deflection assemblies. The deflection device is capable of adopting a folded inactive position as well as a deployed active position in which the deflection assemblies are further apart axially from each other than in the folded inactive position. Furthermore, the diverter comprises a front support frame for the deflection device belonging to the fixed structure, as well as a rear support element for the deflection device fixed to the movable cover, and a connecting follower between the rear support element and the downstream fin assembly of the deflection device. The connecting follower also passes through the sealing membrane.

[0023] Alternatively, separate passages could be provided through the sealing membrane for the actuator / actuators and the connecting follower / follower elements, especially when these elements are circumferentially spaced from each other.

[0024] Preferably, the actuator passes internally through the connecting follower element, these two elements preferably being coaxial. Another solution would be to have the follower element and the actuator pass through the same passage in the diaphragm, while being offset from each other, preferably in the principal direction of this passage, corresponding preferably to the radial direction of the inverter, or substantially to this direction.

[0025] Preferably, the connecting follower is mounted movable relative to the downstream deflection assembly, so as to adopt a retracted position when the movable structure is in its forward direct thrust position, and an axially offset position of the deflection device when the movable structure is in its rearward thrust reversal position, in which the downstream deflection assembly is further axially away from the rear support element than in the forward direct thrust position. Advantageously, it is therefore provided that the downstream deflection assembly of the deflection device is further away from the rear support element in the rearward thrust reversal position.This functionality, made possible by the specific placement of the connecting follower between the downstream deflection assembly and the rear support element, ensures higher reversing performance while maintaining a reduced axial footprint in the direct thrust configuration. Indeed, the reversing performance is enhanced by the axial offset of the downstream deflection assembly, which can therefore be axially displaced from the movable cowling upstream in the thrust reversing configuration. In other words, the invention allows for a simple and reliable adjustment of the axial position of the deployed deflection device in the thrust reversing configuration.

[0026] Alternatively, the connecting follower element could be a fixed element with respect to the rear support element, and with respect to the most downstream deflection assembly of the deflection device.

[0027] According to another alternative, the deployment of the diverter device could be achieved by means other than pulling on its downstream diverter assembly, the latter then no longer needing to be mechanically connected to the movable cover. In this case, deployment could, for example, be carried out using one or more cylinders mounted on the fixed structure of the inverter, and which therefore do not need to pass through the sealing membrane downstream.

[0028] Preferably, the connecting follower is mounted to slide relative to the downstreammost deflection assembly of the deflection device. Other relative movements could nevertheless be provided between these elements, in order to ensure the passage of the connecting follower from its retracted position to its axial offset position of the deflection device, without departing from the scope of the invention.

[0029] Preferably, the rear support element is a fitting, or a rear support frame delimiting downstream the housing of the movable hood.

[0030] Preferably, the actuator's mounting point is located on the rear support element. Alternatively, the actuator could pass through this rear support element and be fixed downstream of it, still on the movable cover.

[0031] It is noted that the flow deflection device can not only take the form of a deployable deflection device, such as a finned deployable deflection grid, but also the form of a fixed deflection device, such as a fixed grid. It can also be a flow deflection device in the form of a deployable membrane, single or multiple, the latter case corresponding to several membranes following one another axially.

[0032] Finally, the invention also relates to an aircraft propulsion assembly comprising such a reverser.

[0033] Other advantages and features of the invention will appear in the detailed, non-limiting description below. Brief description of the drawings

[0034] The detailed description that follows refers to the accompanying drawings on which:

[0035] [Fig.1] is a schematic half-view in longitudinal section of a propulsion assembly, comprising a thrust reverser shown in direct thrust configuration; [Fig.2] is a half-view in longitudinal section of the reverser equipping the propulsion assembly shown in [Fig.1], with the reverser shown in direct thrust configuration;

[0036] [Fig.2A] is a cross-sectional view of part of the inverter shown in the previous figure, essentially representing the secondary vein obturation membrane, in the folded position;

[0037] [Fig.3] is a longitudinal half-sectional view similar to that of [Fig.2], with the reversing gear shown in a thrust reversal configuration;

[0038] [Fig.3A] is a cross-sectional view of a part of the inverter shown in the previous figure, essentially representing the secondary vein obturation membrane, in the deployed position;

[0039] [Fig.4A] is a view similar to that of [Fig.2A], according to an alternative embodiment;

[0040] [Fig.4B] is a view similar to that of [Fig.4A], with the sealing membrane in the deployed position;

[0041] [Fig.5] is a more detailed longitudinal sectional view of the inverter in the form of a preferred embodiment of the invention, and shown in a direct thrust configuration;

[0042] [Fig.6] is a perspective view of part of the reverser shown in [Fig.5], with the reverser shown in thrust reversing configuration;

[0043] [Fig.7] is a view similar to that of [Fig.5], with the reverser shown in thrust reversal configuration. Detailed description of implementation methods

[0044] Figure [Fig.1] shows a propulsion assembly 1 of an aircraft, having a longitudinal central axis Al.

[0045] Hereafter, the terms "upstream" and "downstream" are defined relative to a general SI sense of gas flow through the propulsion assembly 1, along the axis Al when this assembly generates direct thrust. The terms "upstream" and "downstream" could respectively be substituted by the terms "front" and "rear", with the same meaning.

[0046] The propulsion unit 1 comprises a turbomachine 2, a nacelle 3 and a mast (not shown), intended to connect the propulsion unit 1 to a wing (not shown) of the aircraft.

[0047] In this example, the turbomachine 2 is a twin-spool, turbofan 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 turbofan engine 2 has a fan casing 11 connected to the gas generator by structural arms 12.

[0048] The nacelle 3 comprises a front section forming an air inlet 13, a middle section which includes two blower hoods 14 enveloping the blower housing 11, and a rear section 15.

[0049] In operation, an airflow 20 enters the propulsion assembly 1 through the air inlet 13, passes through the fan 5, and then splits into a primary flow 20A and a secondary flow 20B. The primary flow 20A flows in a primary gas circulation channel 21A through the gas generator. The secondary flow 20B flows in a secondary channel 21B surrounding the gas generator. The secondary channel 21B is radially delimited inwardly by a fixed internal fairing that encloses the gas generator. In this example, the fixed internal fairing comprises a first section 17 belonging to the median section 14, and a second Section 18 extends rearward from the first section 17, forming 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 referred to as the radially internal boundary wall 18 of the secondary flow 21 B, or the internal wall 18.

[0050] Radially outwards, the secondary stream 21B is delimited by the fan housing 11, and, in the configuration of [Fig. 1], by one or more movable reversing hoods 33 forming part of the rear section 15 of the nacelle 3, which will be described later. More specifically, between the fan housing 11 and the reversing hoods 33, there is an outer ring 40 of an intermediate housing 42, the latter comprising the aforementioned structural arms 12, the radially external end of which is fixed to this ring 40. This ring therefore also contributes to delimiting the secondary stream 21B radially outwards, being located in the downstream axial extension of the fan housing 11.

[0051] The nacelle 3 therefore comprises a thrust reverser 30 (shown schematically and partially in [Fig. 1]), centered on the axis A1 and comprising, on the one hand, a fixed structure 31 integral with 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, onto which is attached a streamlined aerodynamic portion called a deflection edge 46B, which guides the flow of the reversed jet. This front frame 46 allows the connection with the fan casing 11, in a known manner.

[0052] The inverter also includes several deployable deflection grids 32, one of which is schematically shown in an inactive position folded over [Fig. 1]. However, the flow deflection device could take a form other than that of a deployable deflection device, and could therefore be a fixed deflection device, such as a fixed grid. It could also be a flow deflection device in the form of a deployable membrane.

[0053] To return to the preferred embodiment shown in the figures, the grids 32 follow one another in the circumferential direction. They have a deployable, also called "extendable" character, which allows them to have a smaller axial footprint in the folded inactive position than in the deployed activated position shown in [Fig.3], and enabling them to perform the thrust reversal function.

[0054] Furthermore, the mobile structure 29 comprises the aforementioned movable reverser hoods 33, for example two hoods 33 each extending over an angular amplitude of approximately 180°. This configuration with two hoods 33 is particularly well suited in the case of a nacelle design in which the hoods / walls 18 are also mounted articulated, the reverser 30 then having a so-called "D-shaped" architecture, known by the Anglo-Saxon term "D-Duct". In this design, hoods 18 and 33 are connected so that they open and close simultaneously during engine maintenance. However, other designs are possible, such as a "C-duct" or an "O-duct".

[0055] Each movable reversing gear cover 33 comprises a radially external wall 50 forming an external aerodynamic nacelle surface, and a radially internal wall 52 contributing to the outward delimitation of the secondary duct 21B. This wall 52 lies in the downstream continuity of the deflection edge 46B in the direct thrust configuration. The two walls 50 and 52 define a housing 54 open axially at the upstream end of the movable reversing gear cover 33, and in which at least a portion of each grid 32 is located in the folded, inactive position in the direct thrust configuration of the reversing gear.

[0056] Figure 1 schematically shows the reversing gear 30 in a forward thrust configuration, known as "direct jet," corresponding to a standard flight configuration. In this configuration, the cowlings 33 of the movable structure 29 are in a closed position, known as the forward thrust or "direct jet" position, in which these reversing gear cowlings 33 rest on the fixed structure 31. Indeed, in the direct thrust configuration, the upstream end 52A of the radially internal wall 52 of each cowling 33 rests axially against a box section of the forward frame, the deflection edge 46B being arranged radially inwards.

[0057] The movable structure 29 is thus translationally movable relative to the fixed structure 31 along the axis A1 of the inverter, between the forward direct thrust position shown in [Fig. 1], and a rearward thrust reversal position which will be described later. In the forward direct thrust position of the movable structure 29, each grid 32, in its folded inactive position, is arranged at least partially in the housing 54 of the inverter covers 33, being isolated from the secondary stream 21B by the radially internal wall 52 of these sliding covers 33. This wall 52, forming the external wall of the secondary stream, is also called the internal acoustic panel.

[0058] The principle of the invention is schematically illustrated in Figures 2 and 3, with the reversing gear in the direct thrust configuration in Figures 2 and 2A, and in the reverse thrust configuration in Figures 3 and 3A. Thus, the movable structure 29 is shown in the forward direct thrust position in Figures 2 and 2A, and in the retracted reverse thrust position in Figures 3 and 3A. Furthermore, one of the reversing gear's grids 32 is shown in the folded inactive position in [Fig. 2], and in the deployed active position in [Fig. 3]. Finally, a sealing membrane 58 of the secondary vein, which will be described later, is shown in a folded position in figures 2 and 2A, and in a deployed position in figures 3 and 3A.

[0059] In [Fig. 3], it is shown that the deflection edge 46B and the upstream end of the movable hood 33 axially define, on the secondary flow 21B, a radial extraction opening 56 for at least a portion 20B' of the secondary flow 20B. This opening 56 of the secondary flow 21B is thus delimited upstream by the deflection edge 46B. Conventionally, this edge flares radially outwards towards the rear, to define an airflow 20B' intended to pass through this opening 56 when the movable structure is in this rearward thrust reversal position. In other words, the deflection edge 46B, here made rigidly, has a shape that gradually moves away from the axis Al from front to back, to guide / deflect the air through the opening 56 and towards the grids 32, in thrust reversal configuration.Conversely, this opening 56 of the secondary vein 21B is notably delimited downstream by the upstream end 52A of the radially internal part 52 of the hood 33. .

[0060] 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 secondary flow closure membranes 58, each membrane 58 being deployable. An embodiment in which a single membrane 58 is associated with each movable inverter cover 33 will be described below, exhibiting an identical or similar angular amplitude, but it remains possible to provide several circumferentially adjacent membranes associated with each cover 33. Similarly, only the interaction between a membrane 58 and its associated cover 33 will be described below, it being understood that this interaction is identical or similar for all covers of the inverter 33.Also, the cooperation between one of the membranes 58 and the deployable grid 32 supplied with air by this membrane will be described, it being specified however that the same membrane could supply several circumferentially adjacent grids 32, and / or that the same grid 32 could be supplied by several circumferentially adjacent sealing membranes.

[0061] The membrane 58 can be made of a material known to those skilled in the art for this type of application. For example, it can be an unimpregnated fabric, such as aramid fibers. The membrane 58 can also be made of a composite material with a particularly flexible matrix, such as aliphatic polyurethane, which allows its use under different temperature conditions, particularly lower temperatures for an aliphatic polyurethane membrane than for a silicone membrane. The matrix provides low flexural strength, and the behavior of the resulting structure is indeed that of a membrane. One of the major properties of This membrane 58 is capable of being folded in a perfectly reversible manner (elastically or by fiber sliding) with a very small radius of curvature relative to its surface area, and of having a very thin profile, for example, on the order of 0.1 to 3 mm. For information purposes, it has been observed that this membrane 58 behaves like a boat sail or a parachute / flying wing when it is under pressure.

[0062] The sealing membrane 58 is therefore designed to deflect at least a portion of the secondary flow towards the deflection grid 32 in the deployed active position, when the movable structure 29 is in the thrust reversal position. The membrane 58 is at least partially arranged in the housing 54 of the movable hood 33 when the movable structure 29 is in the forward direct thrust position. To achieve this, a first end of the membrane 58 is fixed to the radially external wall 50 of the movable hood, preferably on or near its upstream end 50A. A second end of the membrane 58b is connected to the radially internal boundary wall 18 by means of attachment means 62, for example, connecting rods hinged to this wall 18 and spaced circumferentially from one another.

[0063] With reference to [Fig.2], when the mobile structure 29 is in the forward direct thrust position, the sealing membrane 58 extends, from its first end 58a, between the radially external wall 50 and the grid 32 in the folded inactive position. It thus travels downstream, in housing 54, until it bypasses downstream this grid 32. After this bypass, the membrane 58 extends upstream between the radially internal wall 52 of the movable cover 33, and the grid 32, still in housing 54. It is then axially clamped between the deflection edge 46B, and the upstream end 52A of the wall 52 of the movable cover 33. Its second end 58b is located near the clamped portion of the membrane, to be connected to the radially external end of the connecting rods 62, in the upright position in the secondary channel 21B.

[0064] As mentioned previously, several deployable grids 32 are preferentially arranged in succession within the inverter along the circumferential direction. These grids 32 can all be identical and arranged in the same way, so as to generate a counter-thrust flow 20B” with a forward axial component. Consequently, the design and operation will be described hereafter for only any one of the grids 32.

[0065] For the support of the deflection grid 32, the inverter also includes a rear support frame for the deflection device 60, as well as a front support frame for the deflection device 70, each of these frames extending in the circumferential direction. The front support frame 70, here forming a front support frame for grid 70, is integrated into the fixed structure 31 of the inverter, while the rear support frame 60, here forming a rear support frame for grid 60, is integrated into the mobile structure 29. The front frame 70 is preferably located in or near a front axial end of the opening 56, while the rear frame 60 connects the two walls 50, 52 of the movable hood 33, delimiting downstream the housing 54. It is noted that the rear frame 60 could be replaced by another rear grid support element, such as a fitting, fixed internally to one and / or the other of the two walls 50, 52 of the movable hood.

[0066] The deployable deflection grid 32 is therefore fixed on these two support frames 60, 70, which are preferably designed to support several adjacent grids 32 in the circumferential direction, or even to support all the grids of the same hood, over an angular sector close to 180°.

[0067] The grid 32 comprises several deflection assemblies, here finned deflection assemblies 32a, arranged axially in succession. As will be described below in a preferred embodiment of the invention, each finned assembly 32a comprises at least one flow deflection fin, preferably of conventional and rigid design, as well as fin support means. The fins within these assemblies 32a could nevertheless be flexible, without departing from the scope of the invention.

[0068] The assemblies 32a which follow one another axially, within the grid thus reconstituted, define a most downstream finned assembly, referenced 32a', and opposite it, a most upstream finned assembly, referenced 32a”. The most upstream finned assembly 32a” is fixed directly on the front frame 70, while the most downstream finned assembly 32a' is fixed on the rear frame 60, preferably indirectly by means of a connecting follower element 72, which will be described later.

[0069] The number of fin assemblies 32a within the grid can vary, and is typically between three and fifteen assemblies, each comprising a fin extending continuously along the entire circumferential length of the grid 32, or which can be interrupted in that same direction. In the schematic views of Figures 2 and 3, only the fins of these assemblies 32a are shown, and not their support means.

[0070] In the active position of [Fig. 3], the fin assemblies 32a are further apart axially from each other than in the inactive position of [Fig. 2], where these assemblies 32a are nested within each other to reduce the overall axial bulk. In this folded inactive position, at least several of these fin assemblies 32 are therefore arranged in the housing 54 of the hood, the open upstream end of which is delimited between the upstream ends 50A, 52A of the walls 50, 52 of the hood 33. Still in this folded inactive position of the grid 32, occupied when the hood 33 is in its forward direct thrust position, the most downstream fin assembly 32a' axially presses the membrane 58 against the rear frame 60, or leaves a small gap remains for the passage of this membrane 58, between the most downstream finned assembly 32a' and the rear frame 60.

[0071] As mentioned above, the downstream fin assembly 32a' can be connected directly to the rear frame, or more preferably indirectly via the connecting follower 72, shown schematically only in Figures 2 and 3. This follower 72 can be fixedly mounted on the two elements 32a', 60, but preferably, it is movable relative to the downstream fin assembly 32a'. Thus, it can adopt a retracted position when the movable structure 29 is in its forward direct thrust position, and an axially offset position of the grid when the movable structure 29 is in its rearward thrust reversal position. In this latter position, the downstream fin assembly 32a' is further axially away from the rear frame 60 than in the forward direct thrust position.

[0072] Indeed, in its retracted position, the follower 72 overlaps axially with several of the finned assemblies 32a of the grid 32, for example with more than a majority of these assemblies 32a, and for example with all or almost all of them. To achieve this, the follower 72 can pass through these finned assemblies 32a.

[0073] The connecting follower 72 is preferably mounted to slide relative to the downstream fin assembly 32a' of the grid, for example, by sliding on the latter in the same direction as the direction in which the grid 32 unfolds / extends. Preferably, this follower 72 serves as a motion transmission element for the deployment of the grid 32 when the inverter is opened. Indeed, when the cover 33 moves rearward, it carries with it the follower 72, which is fixed to the rear frame 60 integrated into this cover. Also, preferably, the beginning of the movement of the cover 33 marks the sliding of the follower 72 relative to the fin assemblies of the grid 32, until this follower 72 comes to an axial stop on the downstream fin assembly 32a'.It is this first part of the movement of the hood 33 that causes the follower 72 to move from its retracted position to its axially offset position of the grid. The continuation of the rearward movement of the hood 33 causes the grid 32 to deploy / extend, which is axially stressed by the follower 72, via the most downstream fin assembly 32a'.

[0074] This design allows, in thrust reversal configuration, for at least some of the finned assemblies 32a located furthest downstream of the grid to be extracted, outside of the housing 54. Thanks to this axial adjustment of the grid 32 relative to the extraction opening 56, the relevant assemblies 32a can thus actively participate in the thrust reversal function, and contribute advantageously to increasing the performance of the reverser.

[0075] In the thrust reversal position of the moving structure shown in [Fig. 3], an axial offset distance of the grid, referred to as "Dad", is observed, defined axially between the rear frame 60 and the most downstream fin assembly 32a'. This is therefore the upstream offset distance of the grid 32 from the rear frame 60. In addition, an axial distance, referred to as "Da", is observed between the rear frame 60 and the upstream end 50A of the radially external wall 50 of the movable hood 33. Preferably, the reverser is designed so that the distance Dad corresponds to at least 50% of the distance Da, and even more preferably to at least 70% of this distance Da, the latter being sufficient to cover the folded grid in the direct thrust configuration.

[0076] Finally, although not described, it is noted that several connecting follower elements 72 could be associated with each grid 32, preferably spaced circumferentially from one another. For example, two elements 72 could be fitted to each deflection grid 32, located respectively near the two circumferential ends of the grid in question.

[0077] Furthermore, conventionally, the inverter comprises one or more actuators to generate the movement of the moving structure 29. Each actuator 80, only one of which is schematically represented in Figures 2 and 3, comprises a first actuator part 80a fixed to the fixed structure 31, and a second actuator part 80b fixed to the moving structure 29, at a fixing point 81 located downstream of the deflection grid 32 and the diaphragm 58. As shown in the figures, the fixing point 81 may be located on the rear frame 60. In this case, at least a portion of the first actuator part 80a may be located in an upstream area relative to the inverter and the front frame 70, referred to as the blower area.

[0078] Alternatively, the second actuator part 80b passes through the rear frame 60, which is then provided with an opening for this purpose. The rear end of the second actuator part 80b is then connected to the fixing point 81 located on one of the walls 50, 52 of the hood, downstream of the rear frame 60.

[0079] At least one actuator 80 is preferably arranged so that it is in the same position as, or substantially in the same position as, one of the connecting follower elements, in the circumferential direction of the inverter. Even more preferably, the second actuator part 80b passes internally through the follower element 72. A coaxial arrangement of the elements 80b, 72 is preferably used. In this configuration, the inverter actuator 80 can be of any type, and preferably a worm gear actuation device.

[0080] One of the particular features of the invention lies in the presence, within the sealing membrane 58, of a passage 86 through which the coaxial assembly formed by the actuator 80 and the follower 72. Furthermore, it is noted that on the membrane 58, there are as many circumferentially spaced passages 86 as there are circumferentially spaced elements 72 and 80. Subsequently, only one of these passages 86, which receives the aforementioned coaxial assembly 72 and 80, will be described.

[0081] The passage 86 extends lengthwise along a principal passage direction 88, preferably corresponding to, or substantially to, the radial direction of the inverter. This direction 88 is defined between an internal radial end of passage 90a and an external radial end of passage 90b. The latter is either closed by a peripheral portion of the membrane or open radially outwards, as shown in Figures 2A and 3A. In this preferred case, each passage 86 takes the form of a cutout opening radially outwards, for example, with a shape that flares slightly in this same direction.

[0082] The passage 86 is thus configured to allow movement of the membrane 58 relative to the coaxial assembly 72, 80, along this passage, during the movement of the mobile structure 29 from its forward position of direct thrust to its rearward position of thrust reversal. In Figures 2 and 3, the passage 86 is schematically represented by the dashed portion of the membrane 58, and is therefore located on its radially external portion.

[0083] When the inverter is opened, the rear frame 60 causes the grid 32 to deploy via the follower 72. Furthermore, the membrane 58 gradually deploys in the secondary channel 21B due to the recoil of the cover 33, which causes the membrane to exit the housing 54, combined with the air from the secondary flow, which inflates the membrane in the secondary channel. This deployment of the membrane 58, which remains downstream of the grid 32, is thus made possible by the relative displacement between the membrane passage 86 and the coaxial assembly 72, 80, as schematically illustrated in Figures 2A and 3A. Indeed, in the direct thrust configuration, the coaxial assembly 72, 80 is located against or near the internal radial end of the passage 90a, as shown in [Fig. 2A]. During the movement of the membrane 58, it causes the coaxial assembly 72, 80 to move in the passage 86, towards the external radial end of passage 90b, as shown in [Fig.3A].

[0084] The passage 86 therefore has the particularity of extending in the radial direction, over only a part of the radial length of the membrane 58.

[0085] In operation, after the inverter is opened, the secondary flow 20B passes through the secondary vein 21B, and comes into contact at least partially with the deployed sealing membrane 58, which forces a portion 20B' of this flow to pass through the opening 56, and therefore to pass subsequently through the grids 32 brought into the deployed active position, in the manner described above. The flow of the portion of the flow 20B' between the fins of the grids 32 leads to the axial straightening of the air, and thus to the generation of the counter-thrust flow 20B”. Furthermore, it is noted that the closing of the inverter is also achieved by means of the actuators, which produce events identical or similar to those described above for opening, but in reverse order.

[0086] Figures 4A and 4B show an alternative, intended to limit air leakage through the membrane 58, via the passages 86, in thrust reversal configuration.

[0087] To achieve this, each passage 86 is no longer hollowed out as in the previous embodiment, but the passage 86 is at least partially sealed by an elastic leak-limiting accessory membrane 92, attached to the sealing membrane 58. The two membranes 58, 92 are made of different materials, since the accessory membrane 92, housed in the passage 86, must have significantly higher elasticity characteristics than the sealing membrane 58. For example, the accessory membrane 92 is fixedly attached along the entire contour of the passage 86, preferably in a general U or V shape. Also, the elastic accessory membrane 92 preferably has a length identical or substantially identical to the length of the passage 86 that it partially seals.As can be seen from the following, the auxiliary membrane 92 is stressed by the coaxial assembly 72, 80, and the extent of deformation of this auxiliary membrane 92 therefore depends on the position of this assembly 72, 80 in the passage 86.

[0088] Thus, this elastic auxiliary membrane 92 is initially configured to adopt a folded position shown in [Fig. 4A], when the movable structure 29 occupies its forward direct thrust position. In this folded position, the elastic auxiliary membrane 92 is constrained in the direction of the internal radial end of the passage 90a. This is the maximum deformation level, in which the auxiliary membrane 92 is held folded between the coaxial assembly 72, 80, and the aforementioned end 90a.

[0089] The membrane 92 is also configured to adopt a deployed position of at least partial closure of the passage 86, shown in [Fig. 4B], and observed when the movable structure 29 occupies its retracted thrust reversal position. In this deployed position, the elastic auxiliary membrane 92 is under less stress due to the greater distance between the internal radial end of the passage 90a and the coaxial assembly 72, 80. This is the minimum deformation level at which the unfolded auxiliary membrane 92 presents the largest surface area within the passage 86, allowing its partial closure in the thrust reversal configuration. This limits air leakage through the passage 86 and thus improves the performance of the reverser.

[0090] By design, the elastic annex membrane 92 is thus configured to deploy automatically, elastically, from its folded position towards its deployed position of obturator, by release of the constraint which is applied to it by the coaxial assembly 72, 80. This release of constraint results in fact from the displacement of the obturator membrane 58 relative to the coaxial assembly 72, 80, along the passage 86, during the displacement of the mobile structure 29 from its forward position of direct thrust to its rearward position of thrust reversal.

[0091] Figures 5 to 7 show a preferred embodiment of the invention, in which each fin assembly 32a of the grid preferably comprises a rigid flow deflection fin 74a and support means 76a for this fin. More specifically, the support means for the fin assemblies 32a form one or more telescopic follower arms 82, preferably two arms 82. To this end, each fin assembly 32a therefore includes a section 76a of each arm 82. In addition, two connecting follower elements 72, of the type described above, respectively form the downstream end of the two telescopic follower arms 82, as downstream end sections of these arms, conventionally fixed to the rear frame 60.

[0092] It is therefore these downstream end sections of the telescopic follower arms 82, lacking deflection vanes 74a, that constitute the connecting follower elements 72, in order to ensure the upstream displacement of the grid 32, in the thrust reversal configuration. Within each arm 82, the axial stop 84 between each follower element 72 and the most downstream vane assembly 32a' is achieved in a conventional manner, such as that encountered between any two adjacent sections of a telescopic arm. This design provides simplicity of operation and manufacture.

[0093] In this preferred embodiment, it is shown that the actuator 80 passes internally through the support means 76a of the vanes, that is, internally through one of the telescopic arms 82, as well as its downstream end section forming the follower element 72. This arrangement can be adopted for each of the two arms 82, or for only one of the two. As indicated previously, a coaxial arrangement of the elements 80, 82 is preferably retained.

[0094] Various modifications can be made by a person skilled in the art to the invention described above, solely by way of non-limiting examples, the scope of which is defined by the appended claims. For example, the thrust reverser 30 can alternatively have a "C" or "O" configuration. Furthermore, all the features disclosed above, in the various preferred embodiments and their alternatives, are combinable. Moreover, it should be noted that in all the figures described above, elements bearing the same numerals correspond to identical or similar elements.

Claims

1. Demands Thrust reverser (30) for an aircraft propulsion system, the reverser comprising a fixed structure (31) equipped with a radially internal boundary wall (18) of a secondary flow (21B) of the propulsion system intended to be traversed by a secondary flow (20B), the reverser also comprising a movable structure (29) comprising at least one movable cowl (33) having a housing (54) open upstream and delimited between a radially external wall (50) and a radially internal wall (52) of the movable cowl (33), the movable structure being translationally displaceable relative to the fixed structure along a longitudinal central axis (Al1) of the reverser, between an advanced direct thrust position and a rearward thrust reversal position, the reverser also comprising a flow deflection device (32) which is arranged, in the advanced direct thrust position of the movable structure, at least partly in the housing (54) of the movable cowl (33),the reversing device also comprising a shut-off membrane (58) designed to divert at least a portion of the secondary flow towards the diverting device (32), when the moving structure (29) is in the thrust reversing rearward position, the shut-off membrane being at least partially located in the housing (54) of the moving cover (33) when the moving structure (29) is in the forward direct thrust position, and comprising a first membrane end (58a), as well as a second membrane end (58b) connected to the radially internal boundary wall (18) by means of attachment means (62), the reversing device also comprising an actuator (80) fixed to the moving structure at a fixing point (81), located downstream of the diverting device (32), characterized in that when the moving structure (29) is in the forward direct thrust position, the shut-off membrane (58),whose first end of the membrane (58a) is fixed on the radially external wall (50) of the movable cover, extends on the one hand between the radially external wall (50) and the deflection device (32), and on the other hand between the radially internal wall (52) of the movable cover (33) and this same deflection device (32) bypassing it downstream, the sealing membrane (58) having a passage (86) through which the actuator (80) passes, the passage being configured, to allow movement of the membrane (58) relative to the actuator (80), along the passage (86), during the movement of the mobile structure (29) from its forward direct thrust position to its rearward thrust reversal position.

2. Inverter according to claim 1, characterized in that the passage (86) extends lengthwise along a main passage direction (88), defined between an internal radial passage end (90a), and an external radial passage end (90b), the latter being closed by a peripheral portion of the membrane, or else open radially outwards.

3. Inverter according to claim 2, characterized in that the passage (86) remains hollow, or at least partially closed by an elastic accessory membrane (92) for leak limiting, the elastic accessory membrane (92) being configured to: - adopt a folded position when the movable structure (29) occupies its forward direct thrust position, folded position in which the elastic membrane (92) is constrained in the direction of the internal radial end of the passage (90a); - adopt a deployed position of at least partial closure of the passage, when the movable structure (29) occupies its rearward thrust reversal position;- to elastically deploy from its folded position to its deployed sealing position, by releasing stress resulting from the displacement of the sealing membrane (58) relative to the actuator (80), along the passage (86), during the movement of the mobile structure (29) from its advanced direct thrust position to its recoiled thrust reversal position.;

4. A diverter according to any one of the preceding claims, characterized in that the flow deflection device (32) is deployable and comprises several axially successive deflection assemblies (32a), the deflection device being capable of adopting a folded inactive position as well as a deployed active position in which the deflection assemblies (32a) are further axially separated from each other than in the folded inactive position, and in that the diverter comprises a front support frame for the deflection device (70) belonging to the fixed structure (31), and a rear support element for the deflection device (60) fixed to the movable cover (33), as well as that a follower element (72) for connecting between the rear support element (60) and the most downstream deflection assembly (32a') of the deflection device, said passage (86) in the sealing membrane (58) also being traversed by the follower element for connecting (72).

5. Inverter according to claim 4, characterized in that the actuator (80) passes internally through the connecting follower member (72), these two elements (72, 80) being preferably coaxial.

6. A reverser according to claim 4 or 5, characterized in that the connecting follower member (72) is mounted movable relative to the most downstream deflection assembly (32a') so as to adopt a retracted position when the movable structure (29) occupies its forward direct thrust position, and an axial offset position of the deflection device when the movable structure (29) occupies its rearward thrust reversal position, in which the most downstream deflection assembly (32a') is further axially offset from the rear support element (60) than in the forward direct thrust position.

7. Inverter according to any one of claims 4 to 6, characterized in that the connecting follower member (72) is mounted sliding relative to the most downstream deflection assembly (32a') of the deflection device (32).

8. Inverter according to any one of claims 4 to 7, characterized in that the rear support element (60) is a fitting, or a rear support frame delimiting downstream the housing (54) of the movable cover (33).

9. Inverter according to any one of claims 4 to 8, characterized in that the fixing point (81) of the actuator is located on the rear support element (60).

10. Aircraft propulsion assembly (1) comprising a reverser (30) according to any one of the preceding claims.

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