Thrust reverser for aircraft turbomachine comprising cable-operated means for deploying and retracting a secondary vein sealing membrane

Abstract

The invention relates to a thrust reverser (30) comprising a movable reverser cover (33) equipped with a radially internal wall (52) contributing to the external delimitation of a secondary flow (21B). The reverser also includes a membrane (58) for closing off the secondary flow, as well as means (62) for deploying and retracting this membrane. According to the invention, the means (62) comprise: - a cable (64) for driving the membrane; and - a return element (66) for the first cable, mounted on the wall (18). Furthermore, in the forward direct thrust position: - a first portion of the cable (64a), which extends from the return element (66), is connected to a first end of the membrane (58a); and - a second portion of the cable (64b), which extends from the return element (66), is connected to the movable reverser cover (33). Figure for the abstract: Fig. 3

Description

Title of the invention: THRUST REVERSER FOR AIRCRAFT TURBO-MACHINE COMPRISING CABLE-OPERATED DEPLOYMENT AND REMOVAL MEANS OF A SECONDARY VEIN OBTURATION MEMBRANE Technical field

[0001] The invention relates to the field of nacelles and thrust reversers for aircraft propulsion systems, and, more particularly, to the means allowing the deployment and removal of the membranes closing the secondary vein of a propulsion system. State of the prior art

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

[0003] The grid reversers currently used in the aeronautical sector generally comprise deflection grids integrated into a fixed structure of the reverser, intended to be connected to a turbomachine casing. A mobile structure of the reverser comprises one or more mobile reverser cowls, and it is mounted so as to be movable in translation relative to the fixed structure between an advanced direct thrust position and a retracted thrust reverser position. In the advanced direct thrust position, the deflection grids are arranged in a cavity of the mobile reverser cowls, and they are isolated from the secondary flow path of the propulsion unit by a radially internal wall of the reverser cowls. On the other hand, in the retracted thrust reverser position, the retracted radially internal wall of the reverser cowls defines an opening for the secondary flow path to the deflection grids.

[0004] To divert at least part of the secondary flow towards this passage opening in the direction of the grilles, the inverter is generally equipped with shutters, which, when deployed, at least partially close the secondary vein. In a known manner, this forces the air of the secondary flow to pass through the passage opening and reach the grilles, which then generate the counter-thrust air flow towards the front.

[0005] The shutter solution is also known to be relatively heavy and bulky. However, climate change is a major concern for many legislative and regulatory bodies around the world. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies both to new types of aircraft and to those in circulation requiring the implementation of technological solutions in order to make them comply with current regulations. For several years now, civil aviation has been mobilizing to contribute to the fight against climate change.

[0006] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes and minimizing greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0007] With this in mind, solutions have been developed for closing the secondary vein using one or more deployable membranes. Such a membrane design is known, for example, from document FR 3 076 864 A1.

[0008] The deployment of a sealing membrane can be carried out using one or more deployment rods, one radially external end of which is connected to one end of the membrane, and one radially internal end of which is articulated on a radially internal delimiting wall of the secondary vein, this wall belonging to the fixed structure of the inverter.

[0009] When the mobile structure moves towards its rearward thrust reversal position, the membrane gradually deploys in the vein by plunging radially towards the inside of the latter, driven by the connecting rod(s) which tilt downstream and also radially towards the inside.

[0010] In the direct jet position, the end of the membrane connected to the connecting rods is generally sandwiched between a deflection edge of the fixed structure, and an upstream end of the radially internal wall of the movable cover.

[0011] The solution of deploying and removing the sealing membrane using connecting rods is satisfactory, but it nevertheless remains perfectible. Indeed, this solution can prove to be restrictive in terms of mass, and / or high forces applied to the membrane in direct thrust configuration. Above all, in reverse thrust configuration, the position of the inclined connecting rods in the secondary vein is not known with great precision, nor that of the membrane end connected to these connecting rods. Statement of the invention

[0012] To at least partially address the drawbacks mentioned above, the invention firstly relates to a thrust reverser for an aircraft propulsion unit, the reverser comprising a fixed structure equipped with a radially internal delimiting wall of a secondary vein of the propulsion unit intended to be crossed by a secondary flow, the reverser also comprising a mobile structure comprising at least one mobile reverser cowl equipped with a radially internal wall participating in the radially external delimitation of the secondary vein, the mobile structure being movable relative to the fixed structure between an advanced direct thrust position, and a retracted thrust reversal position in which the fixed structure and an upstream end of the retracted radially internal wall of the mobile reverser cowl reveal between them an opening for the passage of air through the secondary vein, the thrust reverser also comprising at least one membrane for closing the secondary vein, designed to divert at least part of the secondary flow towards the passage opening, as well as means for deploying and withdrawing the membrane into and out of the secondary vein.

[0013] According to the invention, the means for deploying and removing the membrane comprise:

[0014] - a first membrane drive cable; and

[0015] - a return member for the first cable, mounted on the delimiting wall ra internal dialy of the secondary vein.

[0016] In addition, in the forward direct thrust position:

[0017] - a first part of the first cable, which emerges from the return member, is connected to a first membrane end; and

[0018] - a second part of the first cable, which comes out of the return member, is connected to the mobile inverter cover.

[0019] Thanks to the design specific to the present invention, it is the movable cowl pulling on the first cable which causes the sealing membrane to plunge into the secondary vein. Consequently, in the thrust reversal configuration, the position of the first membrane end proves to be more precisely determinable. This advantage results from the fact that the precise position of the first membrane end depends directly on easily controllable parameters, such as the length of the first cable and the position of the return member on the radially internal delimiting wall of the secondary vein.

[0020] The invention also falls within the scope of technological research aimed at very significantly improving the performance of aircraft. In this sense, it contributes to reducing their environmental impact, here by the use of lightweight and compact sealing membranes, and also by replacing the deployment rods with lighter means generating less aerodynamic disturbances on the secondary flow, in direct thrust configuration.

[0021] The invention preferably provides at least any one of the features following optional techniques, implemented individually or in combination.

[0022] Preferably, the second part of the first cable is connected to one of the following elements of the mobile inverter cover:

[0023] - the radially internal wall participating in the radially external delimitation of the secondary vein;

[0024] - a radially external wall intended to be matched by an external air flow;

[0025] - a guide element for the movable reverser cover.

[0026] The latter case may be preferred, since the guide elements of the hood are usually metallic, unlike the internal and external walls which are generally made of composite material, and therefore more subject to deformation under stress.

[0027] Preferably, the second part of the first cable is connected to the movable inverter cover:

[0028] - directly, by a second end of the first cable fixed to the hood inverter mobile; or

[0029] - indirectly, by a second membrane drive cable having of a first end connected to a second end of the first cable, the second cable having a second end fixed to the movable inverter cover.

[0030] Preferably, in the case of a direct connection between the second part of the first cable and the movable reverser cover, the means for deploying and removing the membrane comprise a guide member for the second part of the first cable, the guide member being mounted on the fixed structure of the reverser, and arranged between the return member and the second end of the first cable. This solution proves advantageously easy to implement, with only the first cable directly connecting the movable cover and the membrane, supplemented by guide and return members for this cable.

[0031] Preferably, in the other case of an indirect connection between the second part of the first cable and the movable inverter cover, the second end of the first cable and the first end of the second cable are connected to each other by a reducer mounted on the fixed structure of the inverter. This reducer advantageously offers an additional degree of freedom in controlling the movement of the sealing membrane inside the secondary vein.

[0032] Preferably, the first portion of the first cable comprises a first end of the first cable, which is attached to the first membrane end.

[0033] The means described above can be duplicated so as to be distributed circumferentially, and preferably being independent of each other by cooperating respectively with distinct points of the first end of the membrane, spaced from each other in the circumferential direction.

[0034] According to another possible embodiment, possibly combinable with the previous one, two devices spaced circumferentially from each other interact with each other, for example by being arranged to cooperate with two opposite circumferential end points of the first membrane end.

[0035] To do this, it is preferentially provided that the inverter comprises two first membrane drive cables, each cooperating with its associated return member, the first two cables being circumferentially spaced from each other, and said first part of each of these two first cables being connected to the first membrane end respectively at two points thereof circumferentially spaced from each other, the means for deploying and withdrawing the membrane comprising a cable for urging the first membrane end towards the radially internal delimiting wall of the secondary vein, the urging cable running circumferentially along the first membrane end between said two points, the two opposite ends of the urging cable being connected at these two points respectively to the first parts of the two first cables,preferably so that the stress cable and the first two cables form a single cable. This configuration is advantageously simple to implement.

[0036] Preferably, a second membrane end, opposite the first membrane end, is fixed to a rear support frame of a structure for redirecting the secondary air flow upstream. In this regard, it is noted that this redirection structure may be formed by one or more thrust reverser grilles, and / or by one or more flexible structures for redirecting the secondary air flow upstream, such as a membrane.

[0037] Preferably, the thrust reverser comprises, integral with the fixed structure of the reverser, such a structure for redirecting the secondary air flow upstream, which can therefore be formed by one or more thrust reverser grilles, and / or by one or more flexible structures for redirecting the secondary air flow upstream. Thus, in the forward direct thrust position of the mobile structure, the reverser grille(s) are preferably located in a cavity of the mobile cowl, being isolated from the secondary flow by the radially internal wall of the reverser cowl. As mentioned above, it is noted that the grilles could be replaced, or provided in combination, with one or more flexible structures of the membrane type, to redirect the secondary air flow upstream.

[0038] Preferably, in the forward direct thrust position:

[0039] - the first part of the first cable emerges from the return member on the downstream side of this last ; and

[0040] - the second part of the first cable emerges from the return member on the upstream side of this last.

[0041] An inverted configuration can nevertheless be envisaged for the arrangement of the first and second parts of the first cable, without departing from the scope of the invention.

[0042] Finally, the invention also relates to a propulsion unit for an aircraft, comprising a turbomachine and a nacelle comprising at least one fan cowl, as well as a thrust reverser as described above.

[0043] Other advantages and characteristics of the invention will appear in the detailed non-limiting description below. Brief description of the drawings

[0044] The following detailed description refers to the accompanying drawings in which:

[0045] [Fig.l] is a schematic half-view in longitudinal section of a propulsion assembly, comprising a thrust reverser, shown in direct thrust configuration;

[0046] [Fig.2] is a schematic half-view in longitudinal section of the inverter equipping the propulsion assembly shown in [Fig.l], in more detail and in the form of a first preferred embodiment of the invention, with the reverser shown in the direct thrust configuration;

[0047] [Fig.3] is a schematic half-view of the inverter shown in [Fig.2], represented in reverse thrust configuration;

[0048] [Fig.4] is a cross-sectional view of the inverter shown in Figures 2 and 3, shown in direct thrust configuration;

[0049] [Fig.5] is a cross-sectional view of the inverter shown in [Fig.4], re shown in reverse thrust configuration;

[0050] [Fig.6] is a schematic half-view in longitudinal section similar to that of the [Fig.2], with the reverser being in the form of a second preferred embodiment of the invention, and shown in the direct thrust configuration;

[0051] [Fig.7] is a schematic half-view of the inverter shown in [Fig.6], represented in reverse thrust configuration;

[0052] [Fig.7A] is a cross-sectional view of the reverser shown in [Fig.6], shown in the direct thrust configuration;

[0053] [Fig.8] is a cross-sectional view of the inverter similar to that of the [Fig.7A], with the reverser being in the form of a third preferred embodiment of the invention, and shown in the direct thrust configuration;

[0054] [Fig.9] is a cross-sectional view of the inverter shown in [Fig.8], re shown in reverse thrust configuration;

[0055] [Fig.lOA]

[0056] [Fig.lOB]

[0057] [Fig.10] are schematic views showing the deployment of the membrane of closing the inverter according to the third preferred embodiment of the invention, during different stages of this deployment;

[0058] [Fig. 11] is a schematic half-view in longitudinal section similar to that of [Fig. 6], with the reverser being in the form of a fourth preferred embodiment of the invention, and shown in the direct thrust configuration;

[0059] [Fig. 12] is a schematic perspective view of the reducer implemented in the inverter shown in the previous figure;

[0060] [Fig. 13] is a longitudinal sectional view of the reducer shown in the preceding figure; and

[0061] [Fig. 14] is a longitudinal sectional view similar to the previous one, according to another sectional plane. Detailed description of embodiments

[0062] [Fig.l] shows an aircraft propulsion unit 1, having a longitudinal central axis A1.

[0063] Subsequently, the terms “upstream” and “downstream” are defined relative to a general direction SI of flow of the gases through the propulsion unit 1, along the axis A1 when the latter generates thrust. These terms “upstream” and “downstream” could respectively be substituted by the terms “front” and “rear”, with the same meaning.

[0064] The propulsion unit 1 comprises a turbomachine 2, a nacelle 3 as well as a mast (not shown), intended to connect the propulsion unit 1 to a wing (not shown) of the aircraft.

[0065] The turbomachine 2 is in this example a double-flow, double-spool turbojet engine comprising, from front to rear, a fan 5, a low-pressure compressor 6, a high-pressure compressor 7, a combustion chamber 8, a high-pressure turbine 9 and a low-pressure turbine 10. The compressors 6 and 7, the combustion chamber 8 and the turbines 9 and 10 form a gas generator. The turbojet engine 2 is provided with a fan casing 11 connected to the gas generator by structural arms 12.

[0066] The nacelle 3 comprises a front section forming an air inlet 13, a middle section which comprises two fan cowls 14 surrounding the fan casing 11, and a rear section 15.

[0067] In operation, an air flow 20 enters the propulsion unit 1 through the air inlet 13, passes through the fan 5 and then divides into a primary flow 20A and a secondary flow 20B. The primary flow 20A flows in a primary gas circulation vein 21A passing through the gas generator. The secondary flow 20B flows in a secondary vein 21B surrounding the gas generator. The secondary vein 21B is delimited radially inwards by a fixed internal fairing which envelops the gas generator. In this example, the fixed internal fairing comprises a first section 17 belonging to the middle section 14, and a second section 18 extending rearwardly from the first section 17, so as to form a part of the rear section 15. This second section 18 is an integral part of a fixed structure of a thrust reverser which will be described below. This same section will subsequently be called the radially internal delimiting wall 18 of the secondary vein 21 B. This section is also called IFS, from the English “Inner Fixed Structure”.

[0068] Radially outwardly, the secondary vein 21B is delimited by the fan casing 11, and, in the configuration of [Fig.l], by one or more movable reverser cowls 33 forming a part of the rear section 15 of the nacelle 3, and which will be described later. More precisely, between the fan casing 11 and the reverser cowls 33, there is provided an outer shroud 40 of an intermediate casing 42, the latter comprising the aforementioned structural arms 12, the radially outer end of which is fixed to this shroud 40. The latter therefore also participates in delimiting the secondary vein 21B radially outwardly, by being located in the downstream axial extension of the fan casing 11.

[0069] The nacelle 3 therefore comprises a thrust reverser 30 centered on the axis A1 and comprising on the one hand a fixed structure 31 secured to the fan casing 11, and on the other hand a structure 29 movable relative to the fixed structure 31. The fixed structure 31 comprises for example a front frame 46 which connects it fixedly to the fan casing 11, preferably via a knife-edge flange assembly located downstream of the outer shroud 11. This front frame 46 contains a profiled aerodynamic part called a deflection edge 46B, which guides the flow in an inverted jet.

[0070] Here, the fixed structure 31 also comprises a plurality of deflection grids 32 arranged adjacent to each other around the axis A1, in a circumferential direction of the reverser 30 and of the propulsion assembly 1. Furthermore, the mobile structure 29 comprises the aforementioned mobile reverser cowls 33, for example two cowls 33 each extending over an angular amplitude of approximately 180°. This configuration with two cowls 33 is particularly well suited in the case of a nacelle design in which the cowls / walls 18 are also mounted articulated, the reverser 30 then having a so-called “D-shaped” architecture, known by the English name “D-Duct”. In this architecture, the cowls 18, 33 are connected so as to open / close simultaneously during maintenance operations on the engine.However, other architectures are possible, such as a so-called "C" architecture, known by the Anglo-Saxon name "C-Duct", or an "O" architecture, known by the Anglo-Saxon name "O-Duct".

[0071] Each movable reverser cover 33 comprises a radially external wall 50, forming an external aerodynamic surface of the inverter and the nacelle, this surface being matched by the external air. Each cowl 33 also comprises a radially internal wall 52 participating in the delimitation of the secondary vein 21B radially outwards. This wall 52 is located in the downstream continuity of the external shell 40 of the intermediate casing. The two walls 50, 52 define a cavity 54 preferably open axially towards the front, at the upstream end of the inverter cowl 33.

[0072] [Fig. 1] shows the reverser 30 in a direct forward thrust configuration, called “direct jet”, corresponding to a standard flight configuration. In this configuration, the cowls 33 of the mobile structure 29 are in a closed position, called the advanced thrust or “direct jet” position, in which these reverser cowls 33 bear on the fixed structure 31, in particular on the deflection edge 46B forming an integral part of the latter. Indeed, in the direct thrust configuration, the upstream end 52a of the radially internal wall 52 of each cowl 33 bears axially against the deflection edge 46B.

[0073] The movable cowl 33 is held in the forward direct thrust position by means for locking this cowl onto the fixed structure 31 of the reverser. These controlled locking means (not shown) are conventional, so they will not be described further. As an indicative example, active locks may be used that are capable of unlocking under load to counter the compressive force of a joint between the movable structure and the deflection edge. This type of lock may in fact overcompress the joint, so that unlocking can then be controlled.

[0074] The mobile structure 29 is thus movable in translation relative to the fixed structure 31 along the axis A1 of the reverser, between the forward direct thrust position shown in [Fig.l], and a retracted thrust reversal position which will be described later. In the forward direct thrust position of the mobile structure 29, the deflection grids 32 are arranged in the cavity 54 of the reverser cowls 33, being isolated from the secondary vein 21B by the radially internal wall 52 of these sliding reverser cowls 29. This wall 52, forming the external wall of the secondary vein, is also called an acoustic internal panel.

[0075] This direct thrust configuration is also shown in Figures 2 and 4, while the rearward thrust reversal position of the mobile structure 29 is shown in Figures 3 and 5.

[0076] In [Fig. 3], it is shown that the internal acoustic panel 52 set back from the inverter covers reveals upstream a passage opening 56 from the secondary vein 21B to the deflection grilles 32. The opening 56 is therefore also delimited upstream by the deflection edge 46B, which flares radially towards the outside going towards the rear, to channel an air flow intended to pass through the grids 32 when the mobile system is in this rearward thrust reversal position. In other words, the deflection edge 46B gradually moves away from the axis A1 going from the front to the rear, to guide / deflect the air towards the grids 32 in the thrust reversal configuration. Downstream, the passage opening 56 is delimited in particular by the upstream end 52a of the radially internal wall 52.

[0077] In order to divert at least a portion of the secondary flow 20B toward the passage opening 56 defined axially between the deviation edge 46B and the upstream end 52a of the radially inner wall 52 of each cover 33, the inverter 30 comprises one or more sealing membranes 58. Subsequently, an embodiment will be described in which a single membrane 58 is associated with each inverter cover 33 while having an identical or similar angular amplitude, but it remains conceivable to provide several circumferentially adjacent membranes associated with each cover 33. Similarly, only the cooperation between a membrane 58 and its associated cover 33 will be described below, it being understood that this cooperation is identical or similar for all the covers of the inverter 33.It is however noted that in addition to the possibility of providing several membranes 58, one or more rigid, more conventional, sealing flaps could be provided in association with this / these membranes, for example alternating in the circumferential direction.

[0078] The membrane 58 may be made of a material known to those skilled in the art for this type of application. For example, it may be a non-impregnated fabric, for example aramid fibers. The membrane 58 may also be made using a composite material whose matrix is ​​particularly flexible, for example aliphatic polyurethane, which allows use under different temperature conditions, in particular lower temperatures in the case of an aliphatic polyurethane membrane than in the case of a silicone membrane. The matrix gives a low bending recovery capacity and the behavior of the structure obtained is indeed that of a membrane. One of the major properties of this membrane 58 is that it can bend in a perfectly reversible manner (elastic or by fiber sliding) with a very small radius of curvature relative to its surface, and to have a very small thickness, for example of the order of 0.1 to 3 mm.For information, it is observed that this membrane 58 behaves like a boat sail or a parachute / a flying wing when it is put under pressure.

[0079] It is recalled that in a conventional grid inverter, the mobile structure slides relative to the fixed structure by means of a rail / slide system which guides the mobile structure from front to rear during the opening phase of the inverter, and from rear to front during the closing phase. A rearward force applied to the mobile structure of the inverter therefore causes it to move backwards, relative to the fixed structure. This force is usually generated by conventional actuators such as cylinders or ball screws.

[0080] Still with reference to Figures 1 to 5 representing a first preferred embodiment of the invention, the membrane 58 has two opposite ends, namely a first end 58a connecting to specific means 62 for deploying and withdrawing the membrane, which will be described below, as well as a second end 58b fixed to a rear frame 60 for supporting the grilles 32. This support is annular or in the form of an annular section connecting in fact the rear end of several adjacent grilles. In the case where the grilles are replaced or provided in combination with one or more flexible structures for redirecting the secondary air flow upstream, such as a deployable membrane, the second membrane end 58b can then be fixed to a rear frame supporting this / these flexible structures for redirecting the flow.

[0081] Concerning the first membrane end 58a, it is therefore connected to one or more devices 61 jointly forming the means 62 for deploying and withdrawing the membrane, specific to the present invention. These devices 62 are circumferentially spaced from each other, for example distributed regularly along the entire length of the first membrane end 58a, in the circumferential direction 63. This involves a number of devices 61, called membrane deployment and withdrawal devices, for example between three and seven.

[0082] Nevertheless, in the remainder of the description of this first preferred embodiment of the invention, only one device 61 will be described, it being understood that the design of the other devices is identical or similar, as is their cooperation with the surrounding elements.

[0083] The device 61 firstly comprises a first cable 64 for driving the membrane 58. In this first embodiment, the device 61 comprises only one cable, namely the first drive cable 64 which is wound around a return member 66, mounted on the radially internal delimiting wall 18 of the secondary stream. This return member 66, preferably in the form of a pulley with an axis of rotation locally parallel or substantially parallel to the circumferential direction 63, is preferably installed on the wall 18 axially at the same level or close to that where the front support frame 46 of the grids 32 is located. To limit aerodynamic disturbances on the secondary flow, the return pulley 66 may be wholly or partly “buried” / “embedded” in the wall 18.

[0084] In the direct thrust configuration as shown in [Fig.2], the first cable 64 is returned radially in the opposite direction by the return pulley 66, causing this cable to undergo an angle of approximately 180°. On either side of the pulley 66, the cable defines a first and a second cable portion, referenced respectively 64a and 64b. This is first of all a first downstream portion 64a, which emerges from the return pulley 66 on the downstream side thereof in relation to the direction of the secondary flow 20B in direct thrust. This first downstream portion 64a, also called the downstream strand of the first cable 64, crosses radially the secondary vein 21B, until it has a first cable end 68a fixed at a point to the first membrane end 58a.

[0085] This then involves a second upstream portion 64b, which emerges from the return pulley 66 on the upstream side thereof in relation to the direction of the secondary flow 20B in direct thrust. This second upstream portion 64b, also called the upstream strand of the first cable 64, also crosses the secondary vein radially, then travels until it has a second cable end 68b fixed to the mobile reverser cover 33.

[0086] In this first preferred embodiment with a single cable 64, the connection of the second upstream part 64b is therefore made directly to the movable cover 33, by a second end 68b of the first cable fixed internally to the radially external wall 50 of the sliding cover 33.

[0087] Indeed, after having passed through the fixed structure 31 of the inverter one or more times, the second part 64b of the first cable 64 comes into contact with a guide member 70 in the form of a pulley or boss, before being connected to the cover 33 via the second cable end 68b. The guide member 70, arranged between the return pulley 66 and the second cable end 68b, is installed on the fixed structure 31, preferably on or near the front frame 46 supporting the grids. The second cable part 64b comes to bear on the upstream part of the guide member 70, to undergo a deviation there orienting it downstream. Thus, at the level of this guide member 70, the second cable part 64b forms an obtuse angle open downstream. In [Fig.2], all or a very large proportion of the second portion of cable 64b is located upstream of the first portion of cable 64b.However, the connection of the second end of cable 68b to the wall 50 of the cover 33 could be carried out further downstream inside the cavity 54, without departing from the scope of the invention. In all cases, at the level of the return pulley 66, the second part of cable 64b is located well upstream of the first part of cable 64a, hence its name “upstream strand”.

[0088] As can be seen in Figures 2 and 4, when the mobile structure 29 occupies its forward direct thrust position, at least a portion of the closure membrane 58 is arranged radially between the deflection grids 32 and the radially inner wall 52 of the reverser cover 33, in the cavity 54. Preferably, the portion of the membrane 58 which is located in this cavity 54 of the reverser cover 33, radially covers the entire length of the grids 32. As a result, when the mobile structure 29 adopts its forward direct thrust position, the first end 58a of the membrane 58 is pinched between the upstream end 52a of the wall 52, and the deflection edge 46B. In order to avoid possible damage to the membrane 58 due to this pinching, the deflection edge 46B may locally have a notch of a shape adapted to receive the upstream end 52a of the wall 52. Thus, the membrane 58 is also pressed into this notch of the deflection edge 46B, by the support of the upstream end of the wall 52.

[0089] During a movement of the movable cowl 33 downstream, carried out to pass from the forward direct thrust position to the thrust reversal position, the first cable 64 driven downstream by the cowl 33 pulls on the membrane 58, via its first end 68a. This causes the first end 58a of this membrane to plunge radially inwards into the secondary vein 21B, at the same time as it is progressively released from the cavity 54, due to the downstream movement of the cowl 33 which moves away from the grids 32.

[0090] As can be seen in [Fig. 3], when the mobile structure 29 occupies its rearward thrust reversal position, the sealing membrane 58 is partly in contact with the upstream end 52a of the radially internal wall 52 of the mobile cowl 33, thus corresponding to the acoustic panel. More precisely, during the rearward movement of the mobile structure 29, the membrane 58 slides on this upstream end 52a of the radially internal wall 52. It should however be noted that depending on the extent of the axial travel of the reverser, the membrane 58 may no longer be in contact with the internal acoustic panel 52 in the fully deployed position of the reverser, where the cowl 33 is in its most rearward position. In such a configuration (not shown), the membrane 58 is thus upstream and at a distance from the upstream end 52a of the wall 52 of the reverser cowl.The contact option corresponds to a minimized stroke of the inverter, while the non-contact option generally corresponds to a smoother membrane shape in reverse jet, therefore more efficient from an aerodynamic point of view.

[0091] The part of the membrane 58 which is located radially outwards relative to its support zone on the wall 52 closes off a part of the upstream axial opening of the cavity 54. The other part located radially inwards closes off at least a part of the secondary vein 21B, thereby diverting at least a part of the secondary flow 20B towards the passage opening 56 in the direction of the grids 32, as can be seen in [Fig. 3].

[0092] During the closing phase of the inverter, the internal wall 52 of the cover advances upstream, which causes the membrane 58 to enter the internal cavity 54, under the grids 32. In parallel, the membrane 58 pulls on the first end 68a of the first cable 64, which allows the latter to rotate around the pulley 66 because at the same time, its second end 68b is also moved upstream due to the progressive advance of the cover 33.

[0093] The connection of the second end 68b of the first cable 64 can be carried out on another element of the movable cowl 33, for example its radially internal wall 52. Another possibility, taking the form of a second preferred embodiment of the invention, consists of fixing the second end 68b of the first cable 64 on a translational guide element of the cowl 33. This guide element preferably takes the form of a rail or a slide 72 which guides the movable cowl 33 from the front to the rear during the opening phase of the reverser, and vice versa during the closing phase. Preferably, the fixing of the second cable end 68b is carried out on an upstream axial end of the rail 72.

[0094] The second preferred embodiment of the invention is shown in Figures 6, 7 and 7A. In these figures, the elements which bear the same numerical references as those shown in Figures 1 to 5 relating to the first embodiment, correspond to identical or similar elements. The same applies to the other embodiments which will be described below.

[0095] Preferably, a device 61 is provided at one circumferential end of the cowl 33, to cooperate with the guide rail 72 which is arranged on this circumferential end of the cowl. The same is true of another device 61, provided at the other opposite circumferential end of the cowl 33, to cooperate with another guide rail 72. In the preferred case where each movable cowl 33 has a general half-cylinder shape shown diagrammatically in [Fig. 7A], the two devices 61 specific to the second embodiment are then, for example, arranged respectively in hour positions at 12 o'clock and at 6 o'clock, or close to these positions. It is in fact in these hour positions that the two rails 72 cooperate with longitudinal fixed beams of the propulsion unit, respectively an upper beam 74 and a lower beam 76.

[0096] The advantage of this arrangement lies in the fact that it is possible to introduce forces into the rails 72, usually metallic, and therefore less deformable than the walls 50, 52 generally made of composite material.

[0097] Between the two devices 61 located at the circumferential ends of the movable cover 33, one or more other additional devices 61 may be provided distributed along the circumferential direction 63 to drive the membrane 58 in the vein. These additional devices 63 are preferably of the type described in the first preferred embodiment, with reference to FIGS. 1 to 5.

[0098] A third preferred embodiment of the invention is shown in Figures 8, 9 and 10A to 10C. In this third embodiment, the two devices 61 of the second embodiment, provided at the two circumferential ends of the movable cover 33 and the membrane 58, are retained. However, instead of being independent of each other by cooperating with two spaced points of the first membrane end 58a, these two dis 61 deployment positives interact with each other, sharing the same cable, as will be described below.

[0099] Indeed, as is apparent from the description of the second preferred embodiment, the first part 64a of each of the first two cables 64, belonging respectively to the two devices 61, is connected to the first membrane end 58a. The two connections with this first membrane end 58 thus take place at two points thereof, corresponding respectively to the two opposite circumferential ends, referenced 78 in FIGS. 9 to 10C.

[0100] In addition to these two first cables 64, the deployment and withdrawal means 62 comprise a cable 80 for stressing the first membrane end 58a towards the wall 18. This stress cable 80 runs circumferentially along the first membrane end 58a, for example in a sheath thereof, between the two aforementioned points 78. The two ends of the stress cable 80, opposite in the circumferential direction 63, are connected at these two points, respectively to the two first cable ends 68a. Preferably, these connections are such that the stress cable 80 and the two first cables 64 form a single cable. This cable common to the two devices 61 can therefore be continuous between the two second ends 68b fixed on the rails 72, without materializing the aforementioned connections.

[0101] When opening the inverter shown diagrammatically in Figures 10A to 10C, the movement of the movable cover 33 has the consequence of pulling on the first two cables 64, which themselves force the cable 80 leading the assembly of the first membrane end 58a to plunge inwards, into the secondary vein.

[0102] According to a fourth preferred embodiment of the invention, combinable with any of the preceding embodiments, the first cable 64 of the deployment device 61 no longer extends to the movable cover 33, but is provided in association with a second cable 84. Figures 11 to 14 illustrate this fourth embodiment, in which the second part 64b of the first cable 64 is effectively connected to the movable cover 33 indirectly, by the second cable 84 for driving the membrane. To do this, the second cable 84 has a first end 84a connected to the second end 68b of the first cable 64, and a second end 84b fixed to the movable cover 33, for example in the downstream bottom of the internal cavity 54 housing the grids 32.

[0103] The connection between the cable ends 68b, 84a can take any form, but preferably, it is made by means of a reducer 86. This is mounted on the fixed structure 31, for example by being fixed on or near the front support frame 46, and / or the deflection edge 46B. At this reducer 86, the junction between the first and second cables 64, 84 forms an open angle towards the downstream direct thrust configuration shown in [Fig.l 1]. This is an angle close to 90°, with the second part 64b of the first cable 64 oriented radially or substantially radially, and with the second cable 84 oriented axially or substantially axially, for example running between two grids 32 into the bottom of the cavity 54 of the cover 33.

[0104] The reducer 86 makes it possible to ensure that during an opening or closing of the inverter, the travel of the first cable 64 differs from the travel of the second cable 84. To do this, the reducer 86 may have a first winder 88 and a second winder 90 integral in rotation, along an axis 92 parallel or substantially parallel locally to the circumferential direction 63.

[0105] With this design, in the case for example where a stroke of the first cable 64 is sought to be less than the stroke of the second cable 84, the latter is then wound onto the second reel 90 having a larger diameter than that of the first reel 88, onto which the first cable 64 is wound.

[0106] Also, during the movement of the movable hood 33 towards its forward direct thrust position, the second cable 84 which unwinds from a larger diameter reel goes faster than the first cable 64 which winds around a smaller diameter reel. In this regard, in this design with reducer 86 making it possible to apply different movement speeds for the two cables 64, 84 during the same phase of opening or closing of the hood 33, it is noted that elastic return means, for example of the spring type, can be implemented to facilitate the winding of these cables.

[0107] Various modifications may be made by those skilled in the art to the invention which has just been described, solely by way of non-limiting examples, and the scope of which is defined by the appended claims. For example, the thrust reverser 30 may alternatively have a “C” or “O” architecture. Furthermore, if the preferred embodiments described above relate to a reverser design with fixed deflection grids, these grids may alternatively be integrated into the mobile structure of the reverser.

Claims

Claims

1. Thrust reverser (30) for an aircraft propulsion unit, the reverser comprising a fixed structure (31) equipped with a radially internal delimiting wall (18) of a secondary vein (21B) of the propulsion unit intended to be traversed by a secondary flow (20B), the reverser also comprising a mobile structure (29) comprising at least one mobile reverser cowl (33) equipped with a radially internal wall (52) participating in the radially external delimiting of the secondary vein (21B), the mobile structure being movable relative to the fixed structure between an advanced direct thrust position, and a retracted thrust reversal position in which the fixed structure and an upstream end (52a) of the retracted radially internal wall of the mobile reverser cowl reveal between them an opening (56) for the passage of air through the secondary vein,the thrust reverser also comprising at least one membrane (58) for closing the secondary flow path, designed to divert at least part of the secondary flow towards the passage opening (56), as well as means (62) for deploying and withdrawing the membrane into and out of the secondary flow path, characterized in that the means (62) for deploying and withdrawing the membrane (58) comprise:, - a first cable (64) for driving the membrane; and - a member (66) for returning the first cable, mounted on the radially internal delimiting wall (18) of the secondary vein, and in that in the advanced direct thrust position: - a first part of the first cable (64a), which emerges from the return member (66), is connected to a first membrane end (58a); and - a second part of the first cable (64b), which emerges from the return member (66), is connected to the movable inverter cover (33).

2. Thrust reverser according to claim 1, characterized in that the second part (64b) of the first cable (64) is connected to one of the following elements of the mobile reverser cowl (33): - the radially internal wall (52) participating in the radially external delimitation of the secondary vein; - a radially external wall (50) intended to be matched by an external air flow; - a guide element (72) of the movable reverser cover.

3. Thrust reverser according to claim 1 or claim 2, characterized in that the second part (64b) of the first cable (64) is connected to the movable reverser cowl: - directly, by a second end (68b) of the first cable fixed to the movable reverser cowl; or - indirectly, by a second membrane drive cable (84) having a first end (84a) connected to a second end (68b) of the first cable (64), the second cable (84) having a second end (84b) fixed to the movable reverser cowl.

4. Thrust reverser according to claim 3, characterized in that in the case of a direct connection between the second part (64b) of the first cable (64) and the movable reverser cowl (33), the means for deploying and withdrawing the membrane (62) comprise a guide member (70) for the second part (64b) of the first cable, the guide member (70) being mounted on the fixed structure (31) of the reverser, and arranged between the return member (66) and the second end (68b) of the first cable.

5. Thrust reverser according to claim 3, characterized in that in the case of an indirect connection between the second part (64b) of the first cable (64) and the movable reverser cover (33), the second end (68b) of the first cable and the first end (84a) of the second cable are connected to each other by a reducer (86) mounted on the fixed structure of the reverser (31).

6. A thrust reverser according to any preceding claim, characterized in that the first portion (64a) of the first cable (64) comprises a first end (68a) of the first cable, which is attached to the first membrane end (58a).

7. Thrust reverser according to any one of the preceding claims, characterized in that it comprises two first cables (64) for driving the membrane, each cooperating with its associated return member (66), the two first cables being spaced circumferentially from each other, and said first part (64a) of each of these two first cables (64) being connected to the first membrane end (58a) respectively at two points (78) thereof spaced circumferentially from each other, and in that the means for deploying and withdrawing the membrane (62) comprise a cable (80) of biasing the first membrane end (58a) towards the radially internal delimiting wall (18) of the secondary vein, the biasing cable (80) running circumferentially along the first membrane end (58a) between said two points (78), the two opposite ends of the biasing cable (80) being connected at these two points (78) respectively to the first parts (64a) of the first two cables (64), preferably so that the biasing cable (80) and the first two cables (64) form a single cable.

8. Thrust reverser according to any one of the preceding claims, characterized in that a second membrane end (58b), opposite the first membrane end (58a), is fixed to a rear frame (60) supporting a structure (32) for redirecting the secondary air flow upstream.

9. Thrust reverser according to any one of the preceding claims, characterized in that in the forward direct thrust position: - the first part of the first cable (64a) emerges from the return member (66) on the downstream side of the latter; and - the second part of the first cable (64b) emerges from the return member (66) on the upstream side of the latter.

10. Propulsion assembly (1) for aircraft, comprising a turbomachine (2) and a nacelle (3) comprising at least one fan cowl (14), as well as a thrust reverser (30) according to any one of the preceding claims.

Images