THRUST REVERSER INCLUDING AN IMPROVED SAFETY SYSTEM FOR DEPLOYING A SECONDARY VENTILATION OBTURATION MEMBRANE

Abstract

The invention relates to a thrust reverser for an aircraft propulsion unit, comprising a membrane for closing a secondary flow path, as well as at least one connecting rod for deploying this membrane, designed to be moved from a first position projecting radially into the secondary flow path when the mobile structure occupies its forward direct thrust position, to a second position folded downstream when the mobile structure occupies its rearward thrust reversal position. According to the invention, the reverser also comprises a device (70) for actuating the connecting rod (62), equipped with a safety system (120) to limit the risks of poor kinematics. Figure for the abstract: Fig. 15

Description

Title of the invention: Thrust reverser comprising an improved safety system for deploying a vein sealing membrane CONDARY technical field

[0001] The invention relates to the field of nacelles and thrust reversers for aircraft propulsion systems, and, more particularly, to systems enabling the deployment of the secondary vent shut-off membranes of a propulsion system. 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 generally include deflection grids integrated into a fixed reverser structure, intended to be connected to a turbomachine casing. A movable reverser structure comprises one or more movable reverser hoods, and it is mounted to move in translation relative to the fixed structure between a forward direct thrust position and a rearward thrust reverser position. In the forward direct thrust position, the deflection grids are arranged in a cavity within the movable reverser hoods, and they are isolated from the secondary flow of the propulsion system by a radially internal wall of the reverser hoods. Conversely, in the rearward thrust reverser position, the radially internal rearward wall of the reverser hoods defines an opening through which the secondary flow passes 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 block the secondary flow. In a known manner, this forces the air from the secondary flow through the passage opening and into the grilles, which then generate the forward counter-thrust airflow.

[0005] The shutter flap solution is also known to be relatively heavy and bulky. Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft But also those already in operation that require the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively contributing to the fight against climate change for several years now.

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

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

[0008] The deployment of a sealing membrane can be more easily achieved 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 boundary 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 unfolds in the vein by plunging radially into the inside of it, driven by the connecting rod(s) which tilt downstream and also radially inwards.

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

[0011] While this technical solution is generally satisfactory, during the initial phase of moving the mobile structure from its forward position of direct thrust to its rearward position of thrust reversal, there is a need to limit the risk of the membrane being pressed against an internal surface of the radially internal wall of the mobile hood. Indeed, such pressing of the membrane hinders its proper radial deployment inwards and is therefore undesirable.

[0012] Furthermore, still in the direct jet position, the radially external end of each deployment strut is located very close to the upstream end of the radially internal wall of the movable cowling. Their simultaneous movement is not without risk, and there is therefore also a need to limit any potential mechanical interference between the radially external end of each strut and the upstream end of the radially internal wall of the movable cowling, whether during the initial phase of movement of the movable structure towards its thrust reversal position, or during the final phase of movement of the structure mobile towards its forward position of direct thrust.

[0013] Finally, there is also a need to strengthen the safety aspect during the deployment of the membrane, in particular to limit the risks of poor kinematics of the deployment rod. Description of the invention

[0014] To meet at least partially these needs, the invention first relates to a thrust reverser for an aircraft propulsion system, the reverser comprising a fixed structure equipped with a radially internal boundary wall for a secondary flow of the propulsion system intended to be traversed by a secondary flow, the reverser also comprising a movable structure comprising at least one movable reverser hood equipped with a radially internal wall participating in the radially external boundary of the secondary flow, the movable structure being displaceable relative to the fixed structure between an advanced direct thrust position, and a rearward thrust reversal position in which the fixed structure and an upstream end of the rearward radially internal wall of the movable reverser hood leave between them an opening for air passage through the secondary flow,the thrust reverser also comprising at least one secondary flow sealing membrane, designed to deflect at least a portion of the secondary flow towards the passage opening, and at least one deployment rod arranged in the secondary flow and having a first end connected, via a connection point, to a first end of the sealing membrane, the membrane deployment rod being designed to be moved from a first position projecting radially in the secondary flow when the moving structure occupies its forward direct thrust position, to a second position folded down downstream when the moving structure occupies its rearward thrust reversal position, and vice versa, the reverser also comprising a deployment rod actuation device, the device connecting the radially internal boundary wall of the flow to a second end of the deployment rod opposite the first,by means of a first articulated linkage, the reverser being configured such that during an initial phase of displacement of the mobile structure from its forward direct thrust position to its rearward thrust reversal position, the actuation device causes a displacement of said first articulated linkage of the deployment rod, radially inwards and / or axially upstream, the actuation device comprising an actuating member preferably having a first end at which is located said first articulated linkage of the deployment rod, as well as a second end opposite to the first, the actuating member being connected, preferably at the level of the , second opposite end, to the radially internal boundary wall of the vein by means of a second articulated link, in the advanced direct thrust position of the mobile structure, the deployment rod and the actuating member forming a salient angle, and the actuating device being designed to, during said initial phase of movement of the mobile structure, force the actuating member to tilt around the second articulated link in a first direction of rotation leading to a reduction of the salient angle.

[0015] According to the invention, the actuation device includes a system for limiting a parasitic rotation of the actuation member around the second articulated link, in a second direction of rotation opposite to the first.

[0016] With this design, the invention implements one or more secondary vein sealing membranes, resulting in a significant reduction in the overall mass of the reversing gear. The invention is therefore the result of technological research aimed at significantly improving aircraft performance and, in this respect, contributes to reducing the environmental impact of these aircraft (decarbonization).

[0017] Furthermore, thanks to this particular movement of the deployment rod at the beginning of the reversing valve opening phase, which allows the diaphragm to be pulled upstream and / or inward, resulting in its detachment, the risks of unwanted contact of this diaphragm with the movable cowling are advantageously reduced, or even eliminated. The same applies to the risks of mechanical interference between the deployment rod and the upstream end of the radially internal wall of the movable cowling, both during the initial phase of movement of the movable structure towards its rearward thrust reversing position, and during the final phase of movement of the movable structure towards its forward direct thrust position.

[0018] Finally, it is noted that the addition of the parasitic rotation limitation system for the actuating member prevents the risk of unwanted kinematics within the actuating device. In particular, it ensures that the actuating member does not rotate in the opposite direction to that desired, by an amplitude that could risk applying an unwanted movement to the deployment rod. By way of example, such parasitic rotation can result from the pressure forces applied to the deploying diaphragm.

[0019] The invention preferably provides for at least one of the following optional technical features, implemented individually or in combination.

[0020] Preferably, the parasitic rotation limitation system of the actuating member is configured so that in the event of parasitic rotation of the actuating member, in the second direction of rotation, the angle which increases remains less than 180°, and preferably less than 120°.

[0021] Preferably, the actuation device includes excitation means, preferably elastic return means, and a transmission member, preferably a cable, the first end of which is connected to the excitation means and the opposite second end of which is connected to the deployment rod, or to the actuating member, or to the second articulated link arranged between the latter.

[0022] According to a preferred embodiment of the invention, the parasitic rotation limitation system of the actuating member comprises:

[0023] - a portion of a stop provided on the actuation member;

[0024] - an additional stop provided on a fitting on which the component is articulated actuation, or provided on the deployment link, or provided on the second articulated link.

[0025] According to another preferred embodiment of the invention, the parasitic rotation limitation system of the actuating member comprises said transmission member.

[0026] According to yet another preferred embodiment of the invention, the parasitic rotation limitation system of the actuating member comprises a retaining cable, the first end of which is connected to the deployment rod, or to the actuating member, or to the second articulated link arranged between the latter, and the second end of which is connected to the radially internal boundary wall, preferably to a fitting on which the actuating member is articulated.

[0027] Preferably, in the forward direct thrust position of the moving structure, the deployment link and the actuating member form the salient angle opening downstream, and the actuating device is designed to:

[0028] - force the actuating member to pivot around the second articulated joint in the first direction of rotation, said first direction of rotation being such that it causes the first end of the actuating member to tilt upstream during said initial phase of movement of the moving structure from its forward direct thrust position to its rearward thrust reversal position; and

[0029] - force the deployment rod to tilt relative to the actuating member, around the first articulated joint and in the second direction of rotation.

[0030] This design also advantageously allows for the tolerance of radial relative displacements between the radially internal and external boundary walls of the flow. These radial displacements can occur depending on the different loading conditions of the inverter components, but also due to the development of play in the inverter resulting from wear of the components over time.

[0031] Furthermore, the forces exerted by the actuation means cause the diaphragm to be under tension, whether in the direct jet position, and / or during the opening / closing of the inverter. This provides better stability for this diaphragm.

[0032] Preferably, the actuation device is of passive design and includes elastic return means, preferably at least one compression spring. Alternatively, it could be controlled means, activated only when required, for example, during the opening and / or closing of the inverter, or only during certain phases of these inverter operations. As indicated above, however, a passive design is preferred that also allows the desired forces to be generated by direct jet, in order to tension the diaphragm and enhance its stability in the cavity where it is stored.

[0033] A hybrid design is also conceivable, in which elastic means would generate the desired forces, but in combination with control means to adjust the stiffness of these elastic means as needed. For example, the stiffness could be adjusted during the opening of the inverter, so that the intensity of the generated forces remains sufficiently high to maintain the desired effect.

[0034] Preferably, the deployment rod and the actuating member together form a three-point mechanical system with respectively the connection point of the membrane, the first articulated link and the second articulated link, the reverser being designed so that during the movement of the mobile structure from its forward direct thrust position to its rearward thrust reversal position, a relative displacement of the deployment rod relative to the actuating member, around the first articulated link, occurs beyond a position in which said three points are aligned, up to a mechanical locking position of the rod, the three-point mechanical system preferably comprising stop means allowing this system to be maintained in the mechanical locking position of the rod.

[0035] The connecting rod's locking position advantageously allows it to maintain the deployed membrane under tension and to withstand very high stresses, which would be extremely difficult to counteract using simple elastic restoring means. This locking position is reached by the three-point mechanical system preferably during a final phase of the movement of the mobile structure towards its rearward thrust reversal position.

[0036] Preferably, said solicitation methods include:

[0037] - elastic means of return;

[0038] - the transmission unit; and

[0039] - a return pulley around which the transmission member travels, this pulley being arranged so that the elastic means transmit to the deployment rod, via the transmission member, forces simultaneously forcing the actuating member to pivot around the second articulated joint in the first direction of rotation, and the deployment rod to tilt relative to the actuating member around the first articulated link, in the second direction of rotation, and preferably, in the advanced position of direct thrust of the mobile structure, the transmission member, for example in the form of a cable, starts from its second end in the direction of the return pulley by going around the first articulated link on the side of said salient angle.

[0040] Here, the elastic return means therefore allow simultaneous action on the two articulated links, for a high compactness of said third means of stressing.

[0041] Preferably, in the advanced position of direct thrust of the mobile structure, the transmission member, for example in the form of a cable, starts from its second end in the direction of the return pulley, bypassing the first articulated link on the side of said salient angle.

[0042] Preferably, the fixed structure of the inverter comprises at least one deflection grid arranged, in a forward position for direct thrust of the moving structure, within a cavity of the moving cover, and isolated from the secondary flow by the radially internal wall of the inverter cover. Alternatively, the deflection grid(s) could be integrated into the moving structure of the inverter, without departing from the scope of the invention. Similarly, it is noted that the grids could be replaced, or used in combination, with a flexible membrane-type structure to redirect the airflow upstream.

[0043] Finally, the invention also relates to a propulsion assembly for an aircraft, comprising a turbomachine and a nacelle having at least one fan cowl, as well as a thrust reverser as described above.

[0044] Other advantages and features of the invention will appear in the detailed, non-limiting description below. Brief description of the drawings

[0045] The detailed description that follows refers to the accompanying drawings on which:

[0046] [Fig.1] is a schematic half-view in longitudinal section of a propulsion assembly, including a thrust reverser, shown in direct thrust configuration;

[0047] [Fig.2] is a schematic half-view in longitudinal section of the inverter equipping the propulsion assembly shown in [Fig.1], in more detail and presented in the form of a preferred embodiment of the invention, with the reverser shown in direct thrust configuration;

[0048] [Fig.2A] is a schematic half-view of the reversing gear shown in [Fig.2], represented in an intermediate configuration between the direct thrust configuration and the thrust reversal configuration;

[0049] [Fig.3] is a schematic half-view of the inverter shown in [Fig.2], represented in thrust reversal configuration;

[0050] [Fig.3A] is a schematic half-view similar to that of the previous figure, with the inverter presented in an alternative embodiment;

[0051] [Fig.3B] is a schematic half-view similar to that of [Fig.3A], with the inverter appearing in an alternative embodiment;

[0052] [Fig.4] is a perspective view of the inverter shown in Figures 2 and 3, re presented in direct thrust configuration;

[0053] [Fig.5] is a perspective view of the inverter shown in [Fig.4], represented in thrust reversal configuration;

[0054] [Fig.6] is a schematic half-view in longitudinal section of a part of the reverser being presented as an alternative embodiment, with this reverser represented in a direct thrust configuration;

[0055] [Fig.7] is an axial view of the part of the inverter shown in the previous figure;

[0056] [Fig.8] is a schematic half-view of the inverter shown in [Fig.6], represented in thrust reversal configuration;

[0057] [Fig.9] is a schematic half-view in longitudinal section of a part of the reverser being presented in the form of another preferred embodiment of the invention, with this reverser represented in direct thrust configuration;

[0058] [Fig. 10] is a schematic half-view of the reverser shown in [Fig.9], represented in thrust reversing configuration;

[0059] [Fig.1OA] is a schematic half-view of a part of the inverter similar to that of [Fig. 10], according to an alternative;

[0060] [Fig. 11] is a schematic half side view of a part of the inverter similar to that of [Fig. 10], according to another alternative;

[0061] [Fig. 12] is a schematic half side view of a part of the inverter similar to that of [Fig. 10], according to yet another alternative;

[0062] [Fig. 13] is a perspective view of a part of the inverter, showing the deployment connecting rod actuation device, according to a preferred embodiment of the invention;

[0063] [Fig. 14] is a side view of the deployment rod actuation device, shown in the previous figure, and in a configuration with the deployment rod parallel to the deployment member;

[0064] [Fig. 15] is a side view of part of the actuation device shown in the previous figure, showing this device in a parasitic rotation configuration of the actuation member;

[0065] [Fig. 16] is a view similar to that of the previous figure, showing the device actuation in an undesired configuration, which could be achieved in the absence of the parasitic rotation limitation system of the actuation member;

[0066] [Fig. 17] is a perspective view of the fitting of the actuation device of the deployment connecting rod, incorporating part of the parasitic rotation limitation system of the actuation member;

[0067] [Fig. 18] is a side view similar to that of [Fig. 14], with the li system parasitic rotational movement of the deployment connecting rod, appearing in the form of an alternative;

[0068] [Fig.19] is a side view similar to that of [Fig.15], with the li system parasitic rotational movement of the deployment connecting rod taking the form of another preferred embodiment of the invention;

[0069] [Fig.20] is a perspective view of the actuating member shown in the figure previous;

[0070] [Fig.21] is a side view similar to that of [Fig.18], with the li system parasitic rotational movement of the deployment connecting rod taking the form of another preferred embodiment of the invention;

[0071] [Fig. 22] is a side view similar to that of [Fig. 18], with the li system parasitic rotation of the deployment connecting rod taking the form of yet another preferred embodiment of the invention;

[0072] [Fig.23] is a perspective view of the connecting rod actuation device folding, with the actuation device taking the form of an alternative;

[0073] [Fig.24] is a cross-sectional view of the actuation device shown in the figure previous; and

[0074] [Fig.25] is a perspective view of the connecting rod actuation device folding, in the form of another alternative. Detailed description of implementation methods

[0075] Figure [Fig. 1] shows a propulsion assembly 1 of an aircraft, having a longitudinal central axis Al.

[0076] Hereafter, the terms "upstream" and "downstream" are defined relative to a general SI sense of gas flow through the propulsion assembly 1, along the axis Al when it generates thrust. These terms "upstream" and "downstream" could respectively be substituted by the terms "front" and "rear", with the same meaning.

[0077] 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.

[0078] In this example, the turbomachine 2 is a twin-spool, twin-flow turbojet engine comprising, from front to rear, a fan 5, a low-pressure compressor The turbojet engine consists of a high-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 has a fan casing 11 connected to the gas generator by structural arms 12.

[0079] 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.

[0080] 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 inwards 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.

[0081] 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.

[0082] The nacelle 3 therefore includes a thrust reverser 30 centered on the axis Al and comprising on the one hand a fixed structure 31 integral with the fan housing 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 housing 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.

[0083] Here, the fixed structure 31 also comprises a plurality of deflection grids 32 arranged adjacent to each other around the axis Al, according to a circumferential direction of the reverser 30 and the propulsion assembly 1. Furthermore, the movable structure 29 comprises the aforementioned reverser movable cowlings 33, for example, two cowlings 33 each extending over an angular range of approximately 180°. This configuration with two cowlings 33 is particularly well-suited to a nacelle design in which the cowlings / walls 18 are also hinged, the reverser 30 then exhibiting a so-called "D-duct" architecture. In this architecture, the cowlings 18 and 33 are connected so as to open / close simultaneously during engine maintenance operations. However, other architectures are possible, such as a so-called "C-Duct" architecture, or an "O-Duct" architecture.

[0084] Each movable reversing gear cover 33 comprises a radially external wall 50, forming an external aerodynamic surface of the reversing gear and nacelle, this surface being enveloped by the outside air. Each cover 33 also comprises a radially internal wall 52 contributing to the delimitation of the secondary channel 21B radially outwards. This wall 52 is located downstream of the outer shell 40 of the intermediate housing. The two walls 50, 52 define a cavity 54, preferably open axially forward, at the upstream end of the reversing gear cover 33.

[0085] Figure 1 shows the reversing gear 30 in a forward direct 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.

[0086] The movable hood 33 is held in the forward direct thrust position by means for locking this hood onto the fixed structure 31 of the reversing unit. These controlled locking means (not shown) are conventional and will therefore not be described further. As an illustrative example, active locks capable of unlocking under load can be implemented to counteract the compressive force on a seal between the movable structure and the deflection edge. This type of lock can, in effect, over-compress the seal so that unlocking can then be initiated.

[0087] The movable structure 29 is thus translationally movable relative to the fixed structure 31 along the axis Al of the inverter, between the forward position of direct thrust shown in [Fig. 1], and a rearward thrust reversal position which will be described later. In the forward direct thrust position of the moving structure 29, the deflection grids 32 are arranged in the cavity 54 of the reverser hoods 33, being isolated from the secondary stream 21B by the radially internal wall 52 of these sliding reverser hoods 29. This wall 52, forming the external wall of the secondary stream, is also called the internal acoustic panel.

[0088] 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, [Fig.2A] representing an intermediate configuration between the two previous ones, observed during the opening and closing of the inverter.

[0089] In [Fig.3], it is shown that the internal acoustic panel is set back 52 from the hoods The reversing valve creates an upstream passage opening 56 for the secondary flow 21B towards the deflection grids 32. This opening 56 is also delimited upstream by the deflection edge 46B, which flares radially outwards towards the rear to channel an airflow destined to pass through the grids 32 when the moving system is in this rearward thrust reversal position. In other words, the deflection edge 46B gradually moves away from the axis A1 from front to back 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.

[0090] In order to divert at least a portion 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 cover 33, the inverter 30 comprises one or more sealing membranes 58. An embodiment in which a single membrane 58 is associated with each inverter cover 33 with an identical or similar angular amplitude will be described, but it remains possible to provide several circumferentially adjacent membranes associated with each cover 33. Similarly, only the interaction between a membrane 58 and its associated cover 33 will be described below, it being understood that this interaction is identical or similar for all the covers of the inverter 33.It is noted, however, that in addition to the possibility of providing several membranes 58, one or more more conventional rigid sealing flaps could be provided in association with this / these membranes, for example alternating in the circumferential direction.

[0091] 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, for example, aramid fibers. The membrane 58 can also be made using Made from a composite material with a particularly flexible matrix, for example aliphatic polyurethane, this membrane can be used 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 true 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 its very thin profile, for example, on the order of 0.1 to 3 mm. For informational purposes, it has been observed that this membrane 58 behaves like a sailboat sail or a parachute / flying wing when pressurized.

[0092] It is recalled that in a conventional gate inverter, the moving structure slides relative to the fixed structure by means of a rail / slide system that guides the moving structure from front to back during the opening phase of the inverter, and from back to front during the closing phase. A rearward force applied to the moving structure of the inverter therefore causes it to move backward relative to the fixed structure. This force is usually generated by conventional actuators such as cylinders or ball screws.

[0093] With further reference to figures 1 to 5 representing a preferred embodiment of the invention, the membrane 58 has two opposite ends, namely a first end 58a connecting to one or more actuating rods 62, and a second end 58b connected to a rear frame 60 supporting the grids 32. This support is annular or in the form of an annular section connecting the rear end of several adjacent grids.

[0094] Regarding the first end of the membrane 58a, it is therefore connected to one or more deployment struts 62 arranged in the secondary channel 21B. For example, several struts 62 are spaced circumferentially from one another, and each is connected to the first end of the membrane 58a via a specific connection point 63 for each strut. However, in the remainder of this description, only one strut will be described, it being understood that the design of the other struts is identical or similar, as is their interaction with the surrounding elements.

[0095] The connection point 63 thus connects the first end of the membrane 58a to a first end 62a of the deployment rod 62.

[0096] In addition, an actuation device 70, specific to the invention, connects the radially internal boundary wall 18 of the vein to a second end 62b of the connecting rod, opposite the first end 62a. This device 70, used for actuation of the connecting rod 62, will be described below.

[0097] As can be seen in Figures 1, 2 and 4, when the movable structure 29 occupies its forward direct thrust position, at least a portion of the sealing membrane 58 is arranged radially between the deflection grids 32 and the radially internal wall 52 of the reversing hood 33, in the cavity 54. Preferably, the portion of the membrane 58 that is in this cavity 54 of the reversing hood 33 radially covers the entire length of the grids 32. As a result, when the movable structure 29 adopts its forward direct thrust position, the first end 58a of the membrane 58 is pinched between the upstream end of the wall 18, and the deflection edge 46B, near the connection point 63 which is located in the vein. 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.

[0098] Also, as can be seen in Figures 2A and 3, when the movable structure 29 moves and reaches its rearward thrust reversal position at the end of this movement, the sealing membrane 58 is partially supported against the upstream end 52a of the radially internal wall 52 of the reversing hood, thus corresponding to the acoustic panel. More precisely, during the rearward movement of the movable structure 29, the membrane 58 slides on this upstream end 52a of the radially internal wall 52.

[0099] In the thrust reversal position of [Fig. 3], the membrane 58 is therefore axially supported downstream against the upstream end 52a. It should be noted that, depending on the extent of the axial stroke 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 cover 33 is in its rearmost position. Such a configuration is shown in [Fig. 3A], which clearly demonstrates that the membrane 58 is located upstream and at a distance from the upstream end 52a of the wall 52 of the reverser cover. The option with contact corresponds to a minimized stroke of the reverser, while the option without contact generally corresponds to a smoother membrane shape in reverse jet, and therefore more aerodynamically efficient.

[0100] Thus, the part of the membrane 58 which is located radially outwards with respect to its bearing area on the wall 52 closes part of the upstream axial opening of the cavity 54, while the other part located radially inwards closes at least part of the secondary vein 21B, thereby diverting at least part of the secondary flow 20B towards the passage opening 56 in the direction of the grids 32.

[0101] Another possibility, not shown, consists of carrying out the external radial attachment of the membrane 58 on the external radial wall 50 of the sliding cover 33.

[0102] Figure 3B represents an alternative in which the grids 32 are replaced by, or provided in combination with, other flow deflection devices to generate the counter-thrust. This involves a flexible structure, of the membrane / textile type 132, used to redirect the flow exiting the passage opening 56 forward.

[0103] As previously stated, the connecting rod actuation device 70 connects the radially internal boundary wall 18 of the stream (also referred to as IFS, from the English "Inner Fixed Structure") to the second end 62b of the connecting rod, corresponding to the radially internal end in the direct thrust configuration. The device 70 and the entire reversing assembly are designed so that the connecting rod 62 is moved from a first position projecting radially into the secondary stream when the moving structure 29 is in its forward direct thrust position, to a second position folded down towards the downstream side when the moving structure 29 is in its rearward thrust reversal position, and vice versa. In the first position shown in [Fig.[2], the connecting rod 62 can indeed adopt a radial or substantially radial orientation in the vein 21B, although a slight inclination from this radial direction remains possible, for example up to a value of 10 to 20°. The connecting rod 62 has a substantial length, for example greater than half the radial thickness of the vein 21B at the point where the connecting rod is located, and even more preferably a length greater than two-thirds of this radial thickness.

[0104] The actuation device 70 first comprises an actuation member 72, in the form of a connecting rod or clevis, having a first end 72a at which is located a first articulated joint 74a with the second connecting rod end 62b. This first articulated joint 74a preferably has a pivot / rotation axis with a circumferential, or substantially circumferential, orientation. A second end 72b of the member 72, opposite the first end 72a, is connected to the radially internal boundary wall 18 by means of a second articulated joint 74b, preferably with a pivot / rotation axis parallel or substantially parallel to that of the first articulated joint 74a. To do this, a fitting 64 is attached to the fixed wall 18, and forms the second articulated link 74b with the second end 72b of the component 72.

[0105] It is noted that in the direct thrust configuration, the connecting rod 62 and the actuating member 72 form a salient angle B1 opening downstream, this angle B1 being large and preferably between 100 and 175°. To achieve this, the member 72 also has a substantially radial orientation in this direct thrust configuration.

[0106] The connecting rod 62 and the component 72 together form a three-point mechanical system with, respectively, the diaphragm connection point 63, the first articulated joint 74a, and the second articulated joint 74b. This three-point mechanical system, as Similar to a "knee" type joint, during the movement of the mobile structure 29 from its forward position of direct thrust to its rearward position of thrust reversal, there occurs a relative displacement of the connecting rod 62 relative to the actuating member 72 around the first articulated joint 74a, which leads, at least initially, to a decrease in the salient angle Bl, as can be seen in [Fig. 2A]. The mechanical system then tends to fold.

[0107] To facilitate the folding of this three-point mechanical system when the reversing mechanism is opened, preferentially passive load means are provided, comprising firstly elastic return means 80a, shown schematically only by an arrow in the relevant figures. These first means 80a, for example of the hinge spring type, force the member 72 to pivot around the second articulated joint 74b in a first direction of rotation, corresponding to the counterclockwise direction in the figures. This first direction of rotation is such that it causes the first end 74a of the member 74 to pivot upstream and radially inwards during an initial phase of movement of the mobile structure 29 from its forward position of direct thrust to its rearward position of thrust reversal.

[0108] The passive excitation means also include second elastic return means 80b, shown only schematically by an arrow in the relevant figures. These second means 80b, for example also of the hinge spring type, force the connecting rod 62 to pivot relative to the member 72 around the first articulated joint 74a, in a second direction of rotation opposite to the first direction, and therefore corresponding to the clockwise direction in the figures.

[0109] Also, thanks to the set of elements described above which form the inverter, it makes it possible to ensure that during the initial phase of movement of the mobile structure 29 from its forward position of direct thrust to its backward position of thrust reversal, the actuation device 70 causes a movement, via its member 74, of the first articulated link 74a radially inwards and / or axially upstream.

[0110] By pulling on the connecting rod 62 in this way at the beginning of the reversing mechanism's opening, it is advantageously prevented from the diaphragm 58, which begins to deploy in the channel 21B, coming into contact with the radially internal surface of the wall 52 of the cover 33, which is moving rearward. Thus, instead of a simple pivoting of the connecting rod 62 relative to the wall 18 at its second end 62b, it is moved upstream and inward with the first linkage 74a by the device 70, in order to cause a sort of separation of the diaphragm. The deployment of this diaphragm 58 is thereby significantly improved and made more reliable.

[0111] On the other hand, thanks to the presence of the first and second elastic return means 80a, 80b exert forces on the diaphragm 58 even in the direct thrust configuration. This keeps the diaphragm under tension when stored in the hood cavity 54, thus contributing to its stability and facilitating its deployment during a subsequent opening of the reversing gear. Also, the three-point mechanical system and its associated elastic return means 80a, 80b allow for, if necessary, radial relative displacements between the two walls 18, 52 in the direct thrust configuration.

[0112] As the moving structure 29 moves rearward, the connecting rod 62 continues to fold downstream and the member 72 continues to fold upstream, resulting in a decrease in the salient angle B1 between these two elements. In this regard, it is noted that the first elastic restoring means 80a are dimensioned so as to generate on the second end 72b of the member 72 a moment of sufficient magnitude to counteract the opposing moment, applied via the connecting rod 62 to its first end 72a, by the membrane 58 inflating with air in the vein 21B.

[0113] The second elastic means 80b, by virtue of their direction of excitation, contribute to making the first end of membrane 58a plunge towards the inside of the vein 21B, so that it takes in air and unfolds progressively.

[0114] Another advantage associated with the presence of the elastic return means 80a, 80b lies in the easy detection, during maintenance, of any connection problem between the first end of the diaphragm 58a and the connecting rod(s) 62. Indeed, this type of detection is usually particularly complicated due to the difficult visual access to this junction. In the proposed design, any connecting rod 62 with a connection defect to the diaphragm 58 will automatically fold back into the channel 21B in its second, downstream folded position, under the combined action of the elastic return means 80a, 80b. Since such a folded connecting rod in the channel 21B remains easily identifiable by an operator performing maintenance, the aforementioned detection is effectively simplified.

[0115] As previously stated, during the opening of the reversing gear, the three-point mechanical system folds back, resulting in a progressive decrease in the salient angle Bl, until it becomes zero at the end of the opening or before the end of the opening, as can be seen in Figures 3, 3A and 3B. In this configuration, where the connecting rod 62 adopts its second folded-down position downstream, the three points are aligned or substantially aligned with the second articulated joint 74b located between the first articulated joint 74a and the connection point 63. This alignment occurs parallel or substantially parallel to the axial direction of the reversing gear.

[0116] According to an alternative shown in Figures 6 to 8, the first and second elastic return means 80a, 80b force, at the end of the inverter opening operation, the displacement of the connecting rod 62 beyond the position in which the three points are aligned. Thus, after being zero, the salient angle B1 reverses to give rise to another salient angle B2 shown in [Fig. 8], placing the three-point mechanical system in a position of mechanical locking of the connecting rod 62. This angle B2, also open upstream but this time with the connecting rod 62 located radially inwards relative to the component 72, can remain small, for example less than 20°.

[0117] Once past the three-point alignment position, the connecting rod 62 cannot pivot counterclockwise relative to the component 72 until the movable cover 33 is moved upstream again following a closing command of the reversing gear. The locking position of the connecting rod 62 advantageously allows it to keep the diaphragm 58 deployed in a taut manner and to withstand very high stresses, which would be extremely difficult to counteract using simple elastic return means.

[0118] The salient angle B1 becomes zero when the three points are aligned, preferably at around 40% of the reverser opening. The angle then reopens in the opposite direction until the reverser is fully in the reverse position (angle B2, [Fig. 8]). Thus, it may be desirable to pass the alignment state of the three points as quickly as possible in order to reach the locking position of the connecting rod 62.

[0119] In this alternative, the design of the first elastic return means 80a can be modified by incorporating a spring-loaded cylinder. This cylinder 82 comprises a cylinder body 84 hinged to the wall 18, and a movable cylinder rod 86. At its end, the rod 86 is hinged to the end of an arm 88 integral with the actuating member 72. Inside the cylinder 82, a spring 90 forces, via the rod 86 on which it acts, the arm 88 and the member 72 to rotate in the second counterclockwise direction. The arm 88 and the actuating member 72 together form a mechanical return link.

[0120] At the articulation with the cylinder rod 86, the end of the arm 88 advantageously serves as a stop against the wall 18. This stop makes it possible to maintain the mechanical system in the locking position, despite the forces which continue to be generated by the first elastic return means 80a, via the compression spring 90.

[0121] Regardless of the design chosen for the first and second elastic return means 80a, 80b, these preferably generate the aforementioned forces throughout the entire opening phase of the reversing gear. By design, these forces may decrease as this opening occurs, due to the progressive unloading of the springs.

[0122] It is noted that during a closing operation of the inverter, opposite movements occur for the connecting rod 62 and the actuating member 72, leading simultaneously to the loading of the first and second elastic restoring means 80a, 80b. In the final phase of a reverser closing operation, the particular kinematics applied by the actuation device 70 also avoids the risks of mechanical collision between the first end of connecting rod 62a, and the upstream end 52a of the acoustic wall 52.

[0123] According to another preferred embodiment shown in Figures 9 and 10, the excitation means include third elastic means which enable the same functions to be generated as those of the first and second elastic means 80a, 80b of the preferred embodiment described above.

[0124] The third elastic return means 80c comprise a hollow body 92 fixed to the wall 18. The hollow body 92 is made by a fitting, preferably made in one piece, and incorporating a clevis 93 on which the actuating member 72 is articulated.

[0125] Inside this body 92, a compression spring 94 is provided bearing at one end against one end of the body 92, and bearing at the other end on a seat or slide 96 movable in translation inside the body, preferably along the axial direction or substantially along this direction.

[0126] A transmission element, of the cable type 98, comprises a first end 98a connected to the third elastic means 80c, by being connected to the movable seat 96. Its second end 98b, opposite to the first, is mounted on the deployment rod 62, at a point 100 between the first articulated link 74a and the connection point of the membrane (not visible in figures 9 and 10).

[0127] A return pulley 102 is also provided, around which the cable 98 runs, between its two ends 98a, 98b. This pulley 102 is arranged so that, in the first protruding position of the connecting rod 62, occupied in the direct thrust configuration shown in [Fig. 9], the cable 98 runs from its second end 98b towards the return pulley 102, but bypassing the first articulated joint 74a against which this cable 98 rests. The bypass of the cable occurs on the side where the salient angle Bl opens, that is to say, downstream of the first joint 74a. Thus, in this configuration, a portion of the cable 98 forms a V open upstream with a rounded point at the point where it rests against the first articulated joint 74a. Next, the cable winds around the pulley 102 located in the upstream continuation of the spring 94, to reach the seat 96 by passing through the spring 94.

[0128] Thanks to this design, the third elastic means 80c transmit to the connecting rod 62, via the cable 98, forces simultaneously forcing the member 72 to tilt around the second articulated link 74b in the first direction of rotation, and the connecting rod 62 to tilt relative to the member 72 around the first articulated link 74a, in the second opposite direction.

[0129] In thrust reversal configuration shown in [Fig. 10], where spring 94 is more relaxed and unloaded, the cable 98 finds itself at an axial distance downstream of the first articulated link 74a, simply winding around the return pulley 102.

[0130] Figure 10A shows a particular feature: the adjustable stroke of the spring 94. It may be desirable to minimize the spring stroke while still meeting the membrane tension requirements and bringing the connecting rods against the wall 18 in the event of a failure or during maintenance. To reduce the stroke, a shim 99 of variable thickness can be placed in the bottom of the hollow, fitting-shaped body 92, so that the slide 93 bears against this shim 99 during the spring's maximum extension stroke. An adjustable base is also possible, without departing from the scope of the invention.

[0131] It is noted that when the movable cover is opened during a maintenance operation, and without any force being exerted on the membrane, the deployment rod 62 may come into contact with the wall 18, due to the clamping effect caused by the spring 94. In order to avoid such an impact, a stop can be installed between this wall 18 and the rod 62. In the embodiment of [Fig. 10], as well as in other embodiments such as that of [Fig. 13], a stop can be integrated into the fitting 92.

[0132] Furthermore, when the movable hood is opened, the actuating member 72 is intended to quickly stop its rotation around the second articulated joint 74b, in the first direction of rotation. This is specifically designed so that during the subsequent opening of the movable hood, only the deployment rod 62 remains in motion, corresponding to a simple rotation around the first articulated joint 74a, in the first direction. To achieve this, the first articulated joint 74a bears against a stop 101 provided on the fitting 92, which is visible in Figures 9 and 10. This stop 101 is preferably clevis-shaped, with its two U-shaped lugs each receiving the axis of the first articulated joint 74a.

[0133] It is noted that the first articulated link 74a comes into contact with the stop 101 preferentially quite early during the initial phase of the movement of the mobile structure, for example at about 10% of its stroke.

[0134] Fig. 11 represents an alternative, in which the actuation member 72 has an extension 103 which goes upstream beyond the first link 74a. It is this extension 103 which comes into contact with the stop 101 provided on the fitting 92, located here close to the wall 18.

[0135] On the other alternative of [Fig.12], the actuating member 72 has an additional annular stop 105, in the form of a boss, through which passes the axis of the first articulated link 74a. In the locking position shown in [Fig. 12], the stop 101 on the fitting 92 comes into contact with the additional stop 105 on the actuating member.

[0136] With reference now to Figures 13 to 17, the actuation device 70 is shown according to a preferred embodiment of the invention, similar to that of Figures 9 and 10. In this device 70, the fitting 92 is also fixed in a buried or semi-buried manner to the wall 18. In this regard, it is noted that this radially internal boundary wall 18 is formed here by a double skin, namely an inner skin 18a to which an acoustic skin 18b is fixed radially outwards. The inner skin 18a, also referred to as the back skin, fulfills a more structural function for the wall 18.

[0137] The two skins 18a, 18b are radially separated from each other, and they define between them a space 74 in which at least part of the fitting 92 and the spring 94 are located. Here, the fitting 92 is fixed to the two skins 18a, 18b by conventional means, such as rivets or bolts.

[0138] One of the distinctive features is that the actuation device 70 includes a system 120 for limiting unwanted rotation of the actuating member 72 around the second articulated joint 74b in the second direction of rotation. Such unwanted movement can occur, in particular, when the moving structure is in its forward direct thrust position, or during the initial phase of movement of this moving structure. Indeed, the addition of the unwanted rotation limiting system 120 prevents the risk of undesired kinematics within the actuation device 70 in the aforementioned states. In particular, it ensures that the actuating member 72 does not rotate in the opposite direction to the desired one, i.e., in the second direction, to an extent that could risk applying an undesired movement to the deployment rod 62.As an example, such parasitic rotation can result from pressure forces applied to the unfolding membrane.

[0139] In this preferred embodiment, the parasitic rotation limitation system 120 first comprises a stop portion 120a provided on the actuating member 72, corresponding to a longitudinal edge of this member 72 in the form of a connecting rod. It further comprises a supplementary stop 120b provided on the fitting 92, this supplementary stop being arranged downstream of the portion 122 of this fitting which forms the second articulated joint 74b.

[0140] As can be seen in [Fig. 15], the parasitic rotation limitation system 120 of the actuating member 72 is configured so that in the event of parasitic rotation of the actuating member 72, in the second direction of rotation, the angle B1 which increases undesirably remains less than 180°, and preferably less than 120°. Particular care is taken to ensure that the two elements 62, 72 do not reach alignment, corresponding to an angle B1 of 180°, beyond which the situation could become critical.

[0141] Any observed parasitic movement is stopped by the contact of the two stops 120a, 120b. The actuating member 72 can thus no longer rotate in the second direction, driving the connecting rod 62 with it. In the absence of such a safety system 120, the connecting rod 62 could undergo undesired kinematics, which would drive it downstream as shown schematically in [Fig. 16], bringing the diaphragm into a position unsuitable for fulfilling its function of closing the secondary flow in the thrust reversal configuration.

[0142] In the alternative shown in [Fig. 18], the additional stop 120b remains provided on the fitting 92, but at the upstream end of the clevis-shaped part 122 on which the second articulated link 74b is located. The additional stop 120b thus remains situated radially outwards relative to the stop 120a on the longitudinal edge of the actuating member 72.

[0143] In [Fig. 19], another preferred embodiment is shown, in which the additional stop 120b is located on the deployment rod 62. It cooperates with the stop 120a on the actuating member, at one of its upstream ends. Moreover, [Fig. 20] shows this member 72, which has at its opposite downstream end a double yoke to cooperate respectively with the lugs of the yoke defined by the part 122 of the fitting 92.

[0144] Figure 21 represents yet another preferred embodiment, in which the parasitic rotation limitation system 120 of the actuating member 72 includes the transmission cable 98. Indeed, the connection point 100 of this cable is then located on or at the level of the first articulated joint 74a. Any parasitic rotation of the actuating member 72 is thus blocked when the spring 94 becomes fully compressed within the fitting 92. In this respect, the fully compressed spring 94, i.e., when the coils are against each other, is preferably retained when the movable cover is in the direct thrust configuration.

[0145] In the preferred embodiment of [Fig. 22], the parasitic rotation limitation system 120 of the actuating member 72 is formed by a retaining cable, one end of which is connected to the second articulated link, and the other end of which is connected to the fitting 92. This additional cable 120 is added to constrain the movement of the member 72 and prevent it from rotating in the opposite direction beyond a given amplitude, deemed critical. The length of the retaining cable 120 defines this extreme position in which the actuating member can no longer rotate, for safety reasons. Conversely, during the opening of the reversing mechanism's moving structure, the retaining cable 120 slackens without interfering with the kinematics of the transmission cable 98 acting on the spring 94. This additional cable 120 will thus be under no tension and will be completely released in the event of a de- correct bending of connecting rods 62.

[0146] The preferred embodiment of Figures 23 and 24 provides a U-shaped actuation member 72, inside which is the end of the deployment rod 62. In addition, the member 72 is itself located between the two ears of the clevis formed on the part 122 of the fitting 92. This clevis can then even be closed upstream, in order to form an aerodynamic fairing limiting losses on the secondary flow in direct thrust configuration.

[0147] Finally, the preferred embodiment of [Fig.25] provides for a lightened actuation device 70, in which the fitting 92 has a reduced dimension, in particular with the spring 94 centered and guided on a fixed internal rod 128, at the end of which is a spring stop 130.

[0148] 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" shaped architecture. Furthermore, if the preferred embodiments described above relate to a reverser design with fixed deflection grids, these grids can alternatively be integrated into the moving structure of the reverser.

[0149] Finally, it is noted that the elastic means described above can take many forms, such as a torsion, compression, or spiral spring. For example, the legs of a torsion spring can bear against the deployment rod 62 and the wall 18 to ensure the rotation of this component. As for the spiral spring, it can be under tension in a direct-jet configuration, with the cable winding around the spring axis during the recoil movement of the reversing gear cover, in order to actuate the deployment rod 62.

Claims

1. Claims Thrust reverser (30) for an aircraft propulsion unit, the reverser comprising a fixed structure (31) equipped with a radially internal delimiting wall (18) of a secondary flow path (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 flow path (21B), the mobile structure being movable relative to the fixed structure between a forward direct thrust position, and a rearward thrust reversal position in which the fixed structure and an upstream end (52a) of the rearward radially internal wall of the mobile reverser cowl reveal between them an opening (56) for the passage of air through the secondary flow path,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 at least one deployment rod (62) arranged in the secondary flow path and a first end (62a) of which is connected, via a connection point (63), to a first end (58a) of the closing membrane, the membrane deployment rod being designed to be moved from a first position projecting radially into the secondary flow path when the mobile structure (29) occupies its forward direct thrust position, to a second position folded downstream when the mobile structure occupies its retracted thrust reversal position, and vice versa, the reverser also comprising a device (70) for actuating the deployment rod (62),the device connecting the radially internal delimiting wall (18) of the vein to a second end (62b) of the deployment rod opposite the first, by means of a first articulated connection (74a), the reverser being configured so that during an initial phase of movement of the mobile structure from its advanced direct thrust position to its retracted thrust reversal position, the actuating device (70) causes a movement of said first articulated connection (74a) of the deployment rod, radially inwards and / or axially upstream, the actuating device (70) comprising an actuating member, (72) connected to the radially internal delimiting wall (18) of the vein by means of a second articulated connection (74b), in the advanced direct thrust position of the mobile structure (29), the deployment rod (62) and the actuating member (72) forming a salient angle (Bl), and the actuating device being designed to, during said initial phase of movement of the mobile structure (29), force the actuating member (72) to tilt around the second articulated connection (74b) in a first direction of rotation leading to a reduction of the salient angle (Bl), characterized in that the actuating device (70) comprises a system (120) for limiting a parasitic rotation of the actuating member (72) around the second articulated connection (74b), in a second direction of rotation opposite to the first.

2. Inverter according to claim 1, characterized in that the system (120) for limiting parasitic rotation of the actuating member (72) is configured so that in the event of parasitic rotation of the actuating member (72), in the second direction of rotation, the angle (Bl) which increases remains less than 180°, and preferably less than 120°.

3. Inverter according to claim 1 or claim 2, characterized in that the actuating device (70) comprises biasing means, preferably elastic return means (94), as well as a transmission member (98), preferably a cable, a first end of which is connected to the biasing means and a second opposite end of which is connected to the deployment rod (62), or to the actuating member (72), or to the second articulated connection (74b) arranged between the latter.

4. Inverter according to any one of the preceding claims, characterized in that the system (120) for limiting parasitic rotation of the actuating member (72) comprises: - a stop portion (120a) provided on the actuating member (72); - a complementary stop (120b) provided on a fitting (92) on which the actuating member (72) is articulated, or provided on the deployment rod (72), or provided on the second articulated connection (74b).

5. Inverter according to claim 3, characterized in that the system (120) for limiting parasitic rotation of the actuating member (72) comprises said transmission member (98).

6. Inverter according to any one of claims 1 to 3, characterized in that the system (120) for limiting parasitic rotation of the actuating member (72) comprises a retaining cable, a first end of which is connected to the deployment rod (62), or to the actuating member (72), or to the second articulated connection (74b) arranged between the latter, and a second end of which is connected to the radially internal delimiting wall (18), preferably to a fitting (92) on which the actuating member (72) is articulated.

7. A reverser according to any one of the preceding claims, characterized in that in the forward direct thrust position of the mobile structure (29), the deployment rod (62) and the actuating member (72) form the salient angle (Bl) opening downstream, and in that the actuating device (70) is designed to: - force the actuating member (72) to tilt around the second articulated connection (74b) in the first direction of rotation, said first direction of rotation being such that it causes the first end (72a) of the actuating member to tilt upstream during said initial phase of movement of the mobile structure (29) from its forward direct thrust position to its retracted thrust reversal position; and - force the deployment rod (62) to tilt relative to the actuating member (72), around the first articulated connection (74a) and in the second direction of rotation.

8. Inverter according to any one of the preceding claims, characterized in that the actuating device (70) is of passive design, and it comprises elastic return means (94), preferably at least one compression spring.

9. A reverser according to any one of the preceding claims, characterized in that the deployment rod (62) and the actuating member (72) together form a three-point mechanical system with respectively the connection point (63) of the membrane (58), the first articulated connection (74a) as well as the second articulated connection (74b), the reverser being designed so that during the movement of the mobile structure from its forward direct thrust position to its retracted thrust reversal position, a relative movement of the deployment rod (62) relative to the actuating member (72), around the first articulated connection (74a), occurs beyond a position in which said three points are aligned, up to a mechanical locking position of the rod, the three-point mechanical system preferably comprising stop means making it possible to maintain this system in the mechanical locking position of the connecting rod (62).

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.