Thrust reverser including a simplified deployment sealing membrane

Abstract

The invention relates to a thrust reverser (30) for an aircraft propulsion system, comprising a fixed structure (31) equipped with a radially internal boundary wall (18) of a secondary flow (21B), and a movable structure (29) comprising at least one movable reverser hood (33) equipped with a radially internal reverser hood wall (52), the movable structure being movable between an advanced direct thrust position and a retracted thrust reverser position, the thrust reverser also comprising at least one shut-off membrane (58) designed to deflect at least a portion of the secondary flow towards the deflection grid (32) when the movable structure (29) is in the retracted thrust reverser position.According to the invention, the inverter comprises a movable frame (60) for deploying the sealing membrane (58), pivotally mounted on the movable structure (29) of the inverter between a retracted position and a deployed position in the secondary vein (21B). Figure for the abstract: Fig. 4.

Description

Title of the invention: Thrust reverser comprising a deployable sealing membrane SIMPLIFIED 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 sealing membranes. 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 inner wall of the reversing valve covers, this wall delimiting the secondary flow radially outwards. Thus, recesses are provided in this radially inner wall of the reversing valve covers to receive the shut-off flaps in the retracted position, as adopted in direct jet operation. However, in direct jet operation, the presence of the recesses and flaps causes aerodynamic disturbances in the secondary flow. Furthermore, this presence locally limits the placement of an acoustic panel on the radially inner wall of the reversing valve covers.

[0006] To provide a technical solution to these problems, it has been proposed to replace the flaps with one or more sealing membranes. Such a design is, for example, known from document FR 3 076 864 AL

[0007] However, the proposed solutions with sealing membranes remain per fectibles, particularly in terms of ease of implementation and reliability of deployment, as well as in terms of preserving the acoustic surface attached to the secondary vein. Description of the invention

[0008] The invention relates firstly to a thrust reverser for an aircraft propulsion system, the reverser comprising a fixed structure equipped with a radially internal boundary wall of a secondary flow of the propulsion system intended to be traversed by a secondary flow, the reverser also comprising a movable structure comprising at least one movable reverser hood equipped with a radially internal reverser hood wall delimiting the secondary flow radially outwards, the reverser also comprising at least one deflection grid, the movable structure being translationally displaceable relative to the fixed structure along a longitudinal central axis of the reverser, between an advanced direct thrust position and a rearward thrust reversal position,the thrust reverser also comprising at least one shut-off membrane designed to deflect at least a portion of the secondary flow towards the deflection grid when the moving structure is in the thrust reversal retracted position.

[0009] According to the invention, the reverser also comprises a movable frame for deploying the obturator membrane, a radially internal edge of the membrane being fixed to this movable frame, which is pivotally mounted on the reverser's moving structure. The movable frame is designed to be moved between a retracted position, occupied when the moving structure adopts its forward direct thrust position, and a deployed position in the secondary flow, occupied when the moving structure adopts its rearward thrust reversing position. Furthermore, in the retracted position, the movable frame closes an opening through the radially internal wall of the reverser hood. This opening serves to deploy the obturator membrane in the secondary flow and leads into an internal storage space in the reverser's movable hood, in which the membrane is located when the moving structure adopts its forward direct thrust position.

[0010] Thus, the reverser according to the invention incorporates one or more shutter membranes, which provide improved aerodynamic and acoustic performance to the propulsion system equipped with such a reverser. Indeed, in direct thrust, the fabric is housed in the reverser's movable cover, which allows for an external secondary stream practically free of any parasitic geometric singularities that contribute to drag and are detrimental to acoustic treatment. In fact, only the movable deployment frame of the shutter membrane reconstitutes the secondary stream in the direct thrust configuration, the surface area of ​​this frame remaining negligible compared to that encountered in prior art solutions with movable shuttering flaps.

[0011] Furthermore, the design specific to the invention offers ease of implementation of the sealing membrane, as well as high reliability of its deployment, due to the streamlined deployment kinematics. The movable frame also enhances the stability of the membrane, both during its deployment and in its deployed configuration when the movable structure is in the thrust reversal position.

[0012] It is also noted that the proposed design allows for the implementation of a membrane extending over a large angular sector. The number of membranes and associated moving frames can thus remain low within the inverter, resulting in a mass reduction.

[0013] The invention preferably provides for at least one of the following optional technical features, taken individually or in combination.

[0014] According to a preferred embodiment of the invention, the inverter includes at least one mechanical control element for rotation of the mobile deployment frame of the sealing membrane.

[0015] Preferably, the rotating mechanical control element comprises a first end articulated on the fixed wall radially internally delimiting the secondary vein, and a second end, opposite the first, articulated on the movable deployment frame of the obturator membrane, the mechanical control element preferably being a connecting rod. The presence of one or more of these mechanical control elements allows, passively, the pivoting of the movable frame during the axial displacement of the mobile structure between its direct thrust and thrust reversal positions.

[0016] According to another preferred embodiment of the invention, the sealing membrane is inflatable, and the reverser is designed so that the membrane adopts a deflated configuration when housed in the internal storage space of the reverser's movable cover occupying its forward direct thrust position, and an inflated configuration when deployed in the secondary vein with the movable structure in the rearward thrust reversal position.

[0017] Preferably, the transition of the diaphragm from its deflated to its inflated configuration causes the movable frame to pivot from its retracted to its deployed position in the secondary flow. This eliminates the need for mechanical control elements such as the aforementioned connecting rods and further reduces the overall mass of the inverter as well as aerodynamic disturbances in the secondary flow.

[0018] Preferably, the inverter is designed so that the pivoting of the movable frame from its retracted position to its deployed position causes, via a transmission system, An axial displacement of the reversing gear cover from its forward direct thrust position to its rearward thrust reversing position. With this design, where the diaphragm inflation also indirectly causes the axial displacement of the reversing gear cover, the reversing gear actuators can advantageously be single-acting, rather than necessarily double-acting as is conventional in the prior art. This results in cost and weight savings.

[0019] Regardless of the embodiment envisaged, the sealing membrane is preferably equipped with reinforcing hoops. These hoops not only contribute to the mechanical reinforcement of the membrane, but they also give it greater stability.

[0020] Preferably, the movable frame has a general U-shape, with the two free ends of the U pivotally mounted on the movable reversing cover.

[0021] Preferably, the radially internal edge of the membrane also has a general U shape fixed all along the U formed by the movable frame, using a linear connection or a series of adjacent point connections.

[0022] The invention applies equally to a reversing grid belonging to the fixed structure of the inverter, or to its moving structure.

[0023] The invention also relates to a nacelle for an aircraft propulsion assembly, comprising at least one fan cowl, as well as a thrust reverser as described above.

[0024] Finally, the invention also relates to a propulsion assembly for an aircraft, comprising a turbomachine and such a nacelle.

[0025] Other advantages and features of the invention will appear in the detailed, non-limiting description below. Brief description of the drawings

[0026] The detailed description that follows refers to the accompanying drawings on which:

[0027] [Fig.1] is a schematic half-view in longitudinal section of a propulsion assembly, comprising a thrust reverser shown in direct thrust configuration;

[0028] [Fig.2] is a partial perspective view of the reverser equipping the propulsion assembly shown in [Fig.1], with the reverser appearing in the form of a first preferred embodiment of the invention, and represented in direct thrust configuration;

[0029] [Fig.3] is a partial perspective view similar to that of the previous figure, from another angle of view;

[0030] [Fig.4] is a partial perspective view similar to that of [Fig.2], with the reversing gear shown in thrust reversal configuration;

[0031] [Fig.5] is a partial perspective view of the inverter shown in [Fig.4], according to another point of view;

[0032] [Fig.6] is a partial perspective view similar to that of [Fig.5], with the movable reversing cover having been removed for clarity;

[0033] [Fig.7] is a longitudinal half-sectional view, showing the inverter along an al alternative implementation, and represented in direct thrust configuration;

[0034] [Fig.8] is a longitudinal half-sectional view similar to the previous one, with the reversing gear shown in thrust reversal configuration;

[0035] [Fig.9] is a longitudinal half-sectional view, showing the inverter according to another alternative implementation, and represented in direct thrust configuration;

[0036] [Fig. 10] is a longitudinal half-section view similar to the previous one, with the reverser shown in thrust reversal configuration;

[0037] [Fig. 11] is a schematic view in longitudinal half-section of the inverter presented in the form of a second preferred embodiment of the invention, and represented in direct thrust configuration;

[0038] [Fig. 12] is a longitudinal half-section view similar to the previous one, with the reverser shown in thrust reversal configuration;

[0039] [Fig. 13] is a longitudinal half-section view, showing the inverter according to an alternative embodiment, and represented in a direct thrust configuration;

[0040] [Fig. 14] is a longitudinal half-section view similar to the previous one, with the reverser shown in thrust reversal configuration;

[0041] [Fig. 15] is a perspective view showing the inflatable membrane of the alternative shown in Figures 13 and 14, the membrane in its deflated configuration;

[0042] [Fig. 16] is a perspective view similar to the previous one, with the membrane shown in inflated configuration;

[0043] [Fig. 17] is a perspective view showing a guide rail system for the movable reversing hood on a fixed beam of the propulsion assembly allowing integration of the pneumatic supply necessary for inflating the membrane;

[0044] [Fig. 18] is a schematic top view showing another alternative embodiment for the inverter, with the diaphragm in the deflated configuration;

[0045] [Fig. 19] is a schematic top view similar to the previous one, with the membrane shown in inflated configuration;

[0046] [Fig.20] is a schematic top view showing yet another alternative of realization for the inverter, this view being similar to that of [Fig. 19], and representing the membrane in inflated configuration;

[0047] [Fig.21] is a schematic view in longitudinal half-section of the inverter se presented in the form of a third preferred embodiment of the invention, and represented in a direct thrust configuration;

[0048] [Fig.22] is a longitudinal half-section view similar to the previous one, with the reverser shown in thrust reversal configuration. Description of the implementation methods

[0049] Figure [Fig.1] shows a propulsion assembly 1 of an aircraft, having a longitudinal central axis Al.

[0050] Hereafter, the terms "upstream" and "downstream" are defined relative to a general SI direction of gas flow through the propulsion assembly 1, along the axis Al when it generates a direct thrust. These terms "upstream" and "downstream" could respectively be replaced by the terms "front" and "rear", with the same meaning.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] During 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 shroud that encloses 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 rearward from the first section 17, so as to form 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 wall 18, radially internal delimitation of secondary vein 21B.

[0055] 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.

[0056] The nacelle 3 therefore includes a thrust reverser 30 (represented only schematically and partially on [Fig. 1]), centered on the axis Al 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 includes for example a front frame 46 which connects it fixedly to the fan casing 11, preferably via a knife flange assembly located downstream of the outer ferrule 11. This front frame 46 contains a profiled aerodynamic part called a deflection edge 46B, which guides the flow in reverse jet.

[0057] In this preferred embodiment, the fixed structure 31 also comprises a plurality of deflection grids 32 arranged adjacent to one another around the axis Al, in a circumferential direction of the reverser 30 and the propulsion assembly 1. Furthermore, the movable structure 29 comprises the aforementioned movable reverser cowlings 33, for example, two cowlings 33 each extending over an angular amplitude of approximately 180°. This configuration with two cowlings 33 is particularly well suited in the case of a nacelle design in which the cowlings / walls 18 are also mounted hinged, the reverser 30 then having a so-called "D-duct" architecture. In this architecture, hoods 18, 33 are connected in such a way as to open / close simultaneously 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".

[0058] Each reversing gear cowl 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 reversing gear cowl 33, and in which at least a portion of the grids 32 are located in the direct thrust configuration.

[0059] Figure 1 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 bear against the fixed structure 31, in particular against the deflection edge 46B, which is an integral part of the latter. Indeed, in the direct thrust configuration, the upstream end 52A of the radially internal wall 52 of each cowling 33 bears axially against the deflection edge 46B.

[0060] The movable structure 29 is thus translationally movable relative to the fixed structure 31 along the axis A1 of the reverser, 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, the deflection grids 32 are arranged in the housing 54 of the reverser 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.

[0061] The direct thrust configuration is also shown in Figures 2 and 3, while the thrust reversal rearward position of the moving structure 29 is shown in Figures 4 to 6, Figures 1 to 6 together showing a first preferred embodiment of the present invention. In [Fig. 4], it is shown that the rearward internal acoustic panel 52 of the reversing hoods exposes upstream an opening 56 for the secondary stream 21B to the deflection grilles 32. The opening 56 is therefore also delimited upstream by the deflection edge 46B, which flares radially outwards towards the rear, to delimit an airflow intended to pass through the grilles 32 when the moving system is in this thrust reversal rearward position.In other words, the deflection edge 46B gradually moves away from the axis Al from front to back, to guide / deflect the air towards the grids 32 in thrust reversal configuration.

[0062] In order to divert at least part of the secondary flow 20B towards the passage opening 56 defined axially between the deflection edge 46B and the upstream end 52A of the radially internal wall 52 of each hood 33, the inverter 30 includes one or more sealing membranes 58.

[0063] Hereafter, a single membrane 58 will be described for each inverter cover 33. This membrane 58 can extend over a large angular amplitude, for example, from 90° to 120°. It is noted that several membranes 58 can be arranged in a circumferential fashion along each cover. 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 the covers of the inverter 33.

[0064] 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, notably lower temperatures for an aliphatic polyurethane membrane than for a silicone membrane. The matrix provides low flexural strength, and the resulting structure behaves like a membrane. One of the key properties of this membrane 58 is its ability to bend in a perfectly reversible manner (elastically or by fiber sliding) with a very small radius of curvature relative to its surface area, and to have a very small thickness, for example, on 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 pressurized.

[0065] One of the features of the invention lies in the attachment of the membrane 58 to the inverter 30. To achieve this, and with reference to Figures 1 to 6, a movable frame 60 is provided for deploying the membrane 58, the frame 60 being pivotally mounted on the radially internal wall 52 of the movable inverter cover 33. Here, the movable frame 60 preferably has a general U-shape, with a base 60A extending circumferentially with a curvature identical or similar to that of the radially internal wall 52. In addition, the two arms 60B of the U have a substantially axial orientation, being arranged here upstream of the base of the U 60A. The two free ends present on the two branches 60B of the U are pivotally mounted on the radially internal wall 52, by means of two pivot links 62 with coincident axes 64 ([Fig.6]).

[0066] A radially internal edge 64A of the membrane 58 also has a general U-shape fixed along the entire length of the U formed by the movable frame 60, by means of a linear connection, namely an uninterrupted connection along the entire length of these elements 64A, 60 of identical or similar shapes. Alternatively, the linear connection can be replaced by a series of adjacent point connections, preferably close together.

[0067] The radially inner edge 64A of the membrane 58 is thus fixed to the pivoting movable frame 60, while a radially outer edge 64B is fixed to a part of the movable structure 29 of the inverter, here preferably to an inner wall 66 of the movable inverter cover 33. This wall 66, arranged radially around the radially inner wall 52, defines, with an upstream end thereof, an internal space 68 within the thickness of the panel as storage for the membrane 58, in the direct thrust configuration. This internal storage space 68, within the movable inverter cover 33, is indeed intended to house the membrane 58 folded upon itself, for example in accordion form, when the movable cover 33 adopts its advanced direct thrust position as shown in [Fig.2].

[0068] Conversely, in the rearward thrust reversal position, the deployed membrane 58 passes through an opening 70 provided in the radially internal wall 52, and is stretched between its two opposite edges 64A, 64B, as can be seen in figures 4 to 6.

[0069] Reinforcing hoops 72 can be fitted to the membrane 58 not only to strengthen its mechanical strength, but also to improve its stability and control its folding. The hoops 72 are arranged radially and preferably each has a general U-shape, following the shape of the membrane 58.

[0070] The aforementioned opening 70 also has a general U-shape, complementary to that of the frame 60. Indeed, the movable frame 60 is designed to adopt a retracted position when the movable structure 29 assumes its forward direct thrust position. In this retracted position, the frame 60 closes the complementaryly shaped opening 70, thus reconstituting the airflow, namely by replacing the missing portion of the radially internal wall 52. The two parts are flush, so as to limit aerodynamic losses on the secondary flow in the direct thrust configuration.

[0071] This opening 70, which serves for the deployment of the membrane 58 in the secondary vein 21B, therefore opens into the internal space 68 for the storage of this membrane.

[0072] The pivoting frame 60 can thus be moved from its retracted position, as just described, to a deployed position in the secondary channel 21B, shown in Figures 4 to 6, and occupied when the movable structure 29 adopts its retracted thrust reversal position. In this deployed position, the movable frame 60 is pivoted relative to the radially internal wall 52 of the cover 33 until its base 60A is in contact with or close to the fixed wall 18, so as to close off the secondary channel 21B as much as possible.

[0073] To obtain the rotation of the mobile deployment frame 60, the inverter is here equipped with connecting rods 74 arranged in the secondary vein 21 B, and of which a first end 74A is articulated on the fixed wall 18 of the secondary vein 21B, and of which a second end 74B opposite to the first is articulated on the mobile frame 60, preferably on its base 60A.

[0074] With this design, the presence of the connecting rods 74 allows, in a passive manner, the rotation of the mobile frame 60 between its retracted position and its deployed position, during the axial displacement of the mobile structure 29 between its direct thrust position and its thrust reversal position, and vice versa.

[0075] Figures 7 and 8 show an alternative embodiment, in which certain mo Several modifications are provided compared to the first preferred embodiment described above. First, the arrangement of the generally U-shaped movable frame 60 is reversed, since the base of the U 60A is located upstream of the arms of the U 60B, rather than downstream. Another difference lies in the fact that in the direct thrust configuration shown in [Fig. 7], the diaphragm 58 is not folded back on itself, but housed in the internal storage space 68, which is formed here by a portion of the housing 54 of the movable inverter cover 33. More precisely, the diaphragm 58 extends internally along the wall 52. Furthermore, the radially external edge 64B of the diaphragm 58 is fixed to a rear grid frame 76, whereas in the deployed position of the frame shown in [Fig. 8], this taut diaphragm passes through the opening 70.

[0076] During the movement of the mobile structure towards its forward direct thrust position, the upstream end 52A of the radially internal wall 52 presses on the membrane 58, and forces it progressively to re-locate itself in the internal storage space 68.

[0077] Figures 9 and 10 show another embodiment in which the rotating control rods of the movable frame are no longer necessary. In this alternative, the membrane 58 is housed in the internal storage space 68 folded back on itself, like an accordion. This space 68 is more accurately described as an internal cavity formed in the front end of the radially internal wall 52. The opening 70 of this space remains securely closed by the base 60A of the pivoting frame 60 when the latter is in its retracted position as shown in [Fig. 9]. Furthermore, the radially external edge 64B of the membrane is fixed to the bottom of the cavity 68.

[0078] In this alternative, a cable or strap 78 connects the rear grid frame 76 to the base 60A of the pivoting frame 60, being arranged downstream of the membrane 58. During the movement of the mobile structure towards its forward direct thrust position, the cable 78 progressively forces the membrane 58 to fold back on itself and retract into the internal storage space 68. It is the force generated by this cable 78 on the base 60A that allows the rotation of the mobile frame 60 towards its retracted position, preferably in combination with elastic return means associated with the pivot joints 62.

[0079] It is noted that in the first preferred embodiment and its alternatives, the membrane 58 in the deployed state takes the form of a hood, with a main central obturation portion extending substantially radially into the secondary vein 21B. The main central obturation portion is completed by two lateral flanks opposite each other, in the circumferential direction.

[0080] A second preferred embodiment of the invention is shown in Figures 11 and 12. This second embodiment differs from the first essentially in that the membrane The sealing membrane 58 has an inflatable characteristic, meaning that it defines an internal volume that is alternately filled with an inflation fluid and then emptied of the same fluid. In other words, the inflatable sealing membrane 58 is such that it adopts a low-volume deflated configuration when housed in the internal storage space 68, and the reversing movable cover 33 occupies its forward direct thrust position [Fig. 11]. Furthermore, it adopts a larger-volume inflated configuration when deployed in the secondary channel 21B, a configuration observed when the movable structure 29 is in the rearward thrust reversal position [Fig. 12].

[0081] Advantageously, the transition of the membrane 58 from its deflated to its inflated configuration causes the mobile frame 60 to pivot from its retracted position to its deployed position in the secondary vein 21B. Indeed, it is the deployment by inflation of the membrane 58 that is used to pivot the mobile frame 60 towards its deployed position. This frame 60 is represented schematically only in Figures 11 and 12 but has a design identical or similar to that described in the first embodiment and its alternatives. For pivoting in the opposite direction, namely from the deployed position of the frame 60 to its retracted position, the suction of the inflation fluid is used, which forces the membrane 58 to retract inside the storage space 68, and / or elastic return means associated with the pivot joints connecting this frame to the wall 52 of the movable cover 33.

[0082] For injecting the inflation fluid into the internal volume of the diaphragm 58 and for its extraction, any suitable means may be used. For example, in this second preferred embodiment, an inflation cylinder 80 is used, a movable part 82 of which is fixed to the movable cover of the reversing gear 33, and a fixed part 84 of which is integral with the fixed structure 31 of the reversing gear. The movable part 82 constitutes the body of the cylinder, while the movable part 84 is formed by the cylinder rod. Thus, the radially external edge 64B of the diaphragm 58 is open to communicate with one of the chambers of the inflation cylinder 80.In this way, when the reversing movable hood 33 is moved axially towards its thrust reversing position, the inflation fluid is forced out of this chamber towards the internal volume to inflate it, while when the reversing movable hood 33 is moved axially towards its direct thrust position, the inflation fluid is drawn into this chamber by being extracted from the internal volume of the membrane.

[0083] Consequently, the inflation and deflation of the membrane 58 occur automatically during the axial movement of the mobile structure 29, carried out with conventional inverter actuation cylinders (not shown in figures 11 and 12).

[0084] Figures 13 and 14 represent an alternative embodiment, in which the Inflation and deflation of the membrane 58 can also be achieved by any means. In this alternative, the unique feature arises from the presence of a transmission system that uses the pivoting of the membrane 58 to cause the axial movement of the reversing gear cover 33 from its forward direct thrust position to its rearward thrust reversing position. Indeed, in this alternative, it is always the deployment by inflation of the membrane 58 that generates the pivoting of the movable frame 60 towards its deployed position in the secondary channel 21B, as shown in [Fig. 14]. The frame 60 also cooperates with the transmission system 86 to cause the axial movement of the movable cover 33 towards its rearward thrust reversing position.To achieve this, the transmission system 86 comprises the cable or strap 78, one end 78A of which is connected to the rear frame of the grids 76, and the other end 78B of which is fixed to the bottom of the internal storage space 68. From the first end 78A, the cable 78, in a direct thrust configuration, first extends upstream until it meets the upstream side of a support pulley 90, which is connected to the wall 52, optionally by means of a spring-loaded damping device 92. After the support pulley 90, the cable 78 passes through the inflatable membrane 58 folded within the internal storage space 68, running from the radially external edge 64B to the radially internal edge 64A. Near the latter, the cable 78 winds around a return pulley 88 fixed on the mobile frame 60, and more precisely on its base 60A.It then travels radially inwards to its second end 78B fixed in the internal storage space 68.

[0085] Thus, the pivoting of the movable frame 60 in the channel 21B results in the radial displacement of the return pulley 88 towards the interior of this channel, and therefore in the pulling of the cable 78 which, by its upstream contact with the support pulley 90, forces the latter and the entire hood 33 to move axially downstream. One of the advantages of this design lies in the possibility of using reverser actuation cylinders of the reverser type rather than the conventional double-acting type, but single-acting cylinders to control only the axial displacement of the movable structure 29 upstream, towards its forward direct thrust position, and to brake the movable structure 29 during opening.

[0086] In this regard, it is noted that in this alternative, the inflatable membrane 58 can have a so-called inflatable design, shown in Figures 15 and 16. The inflatable tubes 58A follow one another in the radial direction, and communicate with each other by fluidic communication zones 94, which can be crossed by the cable 78, thus helping to fold the membrane 58. In the folded state shown in [Fig. 15], the inflatable tubes 58A are flat and stacked on top of each other, considerably limiting the size of the deflated membrane.

[0087] As previously stated, the inflation fluid can be injected into and extracted from the membrane 58 by any means. For example, with reference to [Fig. 17], a conduit 100 can be provided through a guide rail system 102 allowing axial sliding of the movable reversing cover 33 on a fixed beam 98 of the propulsion assembly. This conduit 100 is then obtained by the hollow nature of one of the elements of the guide rail system 102, through which the inflation fluid can flow towards and / or from the inflatable membrane 58.

[0088] Another alternative is shown in Figures 18 and 19, using guide rail systems 102 to define through them channels 100 for the passage of the inflation fluid, communicating with the radially external open edge 64B of the inflatable membrane 58. Upstream, these channels 100 also communicate with any source 108 of inflation fluid.

[0089] In this alternative, the transmission system 86 is also provided, with its support pulley 90 and its return pulley, both fixed to the movable reversing cover 33 shown schematically only, and with its cable 78 cooperating with the aforementioned pulleys. The second end 78B of the cable 78 is directly connected to the base 60A of the movable frame 60.

[0090] The principles set out above remain applicable for this alternative, in particular the fact of generating the rotation of the mobile frame 60 by the inflation of the membrane, or the drive downstream of the mobile cover 33 by means of the transmission system 86, whose cable 78 bearing on the pulley 90 is pulled radially inwards due to the rotation of the mobile frame 60 towards its deployed position in the secondary vein.

[0091] In this alternative, single-acting actuation cylinders 106 have been shown for the upstream movement of the mobile structure 29, these cylinders being, for example, hydraulic or electric.

[0092] A similar alternative is shown in [Fig. 20], in which the inflation fluid circulation lines 100 are now routed through the rods of the reversing actuator cylinders 106. One of the chambers of these cylinders 106 is thus occupied by the inflation fluid used indirectly to move the moving structure 29 to its rearward thrust reversing position, while the other cylinder chamber is occupied by the actuating fluid enabling the return of the moving structure 29 to its forward direct thrust position. This particular functionalization of the actuator cylinders 106 contributes to reducing the overall size of the reversing mechanism.

[0093] To achieve such a reduction in the overall size of the inverter, another solution (not shown) consists of replacing the cable 78 with a flexible hose through which the inflation fluid can circulate. This essentially contributes to reduce the overall piping within the inverter, resulting in gains in mass, cost, and size.

[0094] Finally, it is noted that all the designs described above relate to fixed-gate inverter architectures, but that each of them could be adapted to a moving-gate architecture.

[0095] For example, in the third preferred embodiment of the invention shown in Figures 21 and 22, the first end 78A of the cable 78 is fixed to the fixed structure 31 near or on the deflection edge 46B. The support pulley 90 is fixed to the front frame of grids 76', and the second end 78B of the cable 78 is fixed to the base 60A of the movable frame 60. Here, the inflation of the membrane 58 causes the frame 60 to pivot, which pulls the cable 78 radially inwards, resulting in its bearing on the pulley 90, which causes the entire movable structure 29, including the grids 32, to move downstream to the rearward thrust reversal position.

[0096] 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 numerical references correspond to identical or similar elements.

Claims

Demands

1. 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 reverser hood (33) equipped with a radially internal reverser hood wall (52) delimiting the secondary flow (21B) radially outwards, the reverser also comprising at least one deflection grid (32), 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 thrust reverser also comprising at least one shut-off membrane (58) designed to deflect at least a portion of the secondary flow towards the deflection grid (32) when the moving structure (29) is in the thrust reverser retracted position, characterized in that it also comprises a movable frame (60) for deploying the shut-off membrane (58), a radially internal edge (64A) of the membrane being fixed to this movable frame (60) pivotally mounted on the moving structure (29) of the reverser, the movable frame being designed to be moved between a retracted position occupied when the moving structure (29) adopts its forward direct thrust position, and a deployed position in the secondary flow (21B), occupied when the moving structure adopts its thrust reverser retracted position, and in that in the retracted position of the movable frame (60), it shuts off an opening (70) through the radially internal wall of the reverser hood (52),this opening (70) serves for the deployment of the sealing membrane (58) in the secondary vein and opens into an internal storage space (68) of the reversing movable cover, in which the membrane (58) is located when the movable structure (29) adopts its forward direct thrust position.

2. Thrust reverser according to claim 1, characterized in that it comprises at least one mechanical element (74) for rotation control of the movable frame (60) for deployment of the sealing membrane (58).

3. Thrust reverser according to claim 2, characterized in that the mechanical rotation control element (74) comprises a first end (74A) articulated on the fixed wall of radially internal delimitation (18) of the secondary vein (21B), as well as a second end (74B), opposite to the first, articulated on the mobile frame (60) of deployment of the obturator membrane, the mechanical control member being preferably a connecting rod (74).

4. Thrust reverser according to claim 1, characterized in that the sealing membrane is inflatable, the reverser being designed so that the membrane adopts a deflated configuration when housed in the internal storage space (68) of the reverser movable cover (33) occupying its forward direct thrust position, and an inflated configuration when deployed in the secondary vein (21B) with the movable structure (29) in the rearward thrust reverser position.

5. Thrust reverser according to claim 4, characterized in that it is designed so that the passage of the membrane (58) from its deflated configuration to its inflated configuration causes the pivoting of the movable frame (60) from its retracted position to its deployed position in the secondary vein (21 B).

6. Thrust reverser according to claim 5, characterized in that it is designed so that the pivoting of the movable frame (60) from its retracted position to its deployed position causes, via a transmission system (86), an axial displacement of the movable reverser cover (33) from its forward direct thrust position to its rearward thrust reversal position.

7. Thrust reverser according to any one of the preceding claims, characterized in that the movable frame (60) has a general U-shape, with the two free ends of the U pivotally mounted on the movable reverser cover (33).

8. Thrust reverser according to the preceding claim, characterized in that the radially internal edge (64A) of the membrane (58) also has a general U shape fixed all along the U formed by the movable frame (60), using a linear link or a series of adjacent point links.

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

10. Propulsion assembly (1) for aircraft, comprising a turbomachine (2) and a nacelle (3) according to the preceding claim.

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