WO2011073558A1 - Reverse thrust device - Google Patents

Abstract

The invention relates to a reverse thrust device (10) for a turbojet nacelle including means for diverting at least part of a turbojet air flow, and at least one cowl (20) that moves in translation in a direction substantially parallel to a longitudinal axis of the nacelle, the cowl (20) being able to alternately pass from a closed position, wherein it ensures the aerodynamic continuity of the nacelle, to an open position, wherein it opens a passage in the nacelle, for a diverted flow. Said mobile cowl (20) is also extended by at least one variable nozzle section (30) that includes at least one rotatably mounted panel (31), said panel (31) being able to pivot towards at least one position, creating a variation in the nozzle section, and also towards a position wherein said panel blocks part of an annular channel of the nacelle. The device is characterized in that it also includes a system (50) for driving the panel, said system including drive means (51, 100) mounted on the cowl (20) and mobile around the circumference of the nozzle (30), and an assembly forming a lever (60) that is pivotably mounted on the cowl and hinged to each end thereof by means of connecting drive rods (71, 72) respectively on the drive means (51, 100) and on the panel (31).

Description

 Thrust reversal device

The invention relates to a thrust reverser, said grids, for a jet engine.

 An aircraft is driven by several turbojets each housed in a nacelle also housing a set of ancillary actuators related to its operation and providing various functions when the turbojet engine is in operation or stopped. These ancillary actuating devices comprise in particular a mechanical thrust reversal system.

 A nacelle generally has a tubular structure comprising an air inlet upstream of the turbojet engine, a median section intended to surround a fan of the turbojet engine, a downstream section housing the thrust reverser means and intended to surround the combustion chamber and the turbojet turbines, and is generally terminated by an ejection nozzle whose output is located downstream of the turbojet engine.

 Modern nacelles are intended to house a turbofan engine capable of generating a hot air flow (also called primary flow) from the combustion chamber of the turbojet, and through the blades of the rotating fan a flow of cold air (secondary flow) flowing outside the turbojet through an annular passage, also called vein, formed between a shroud of the turbojet engine and an inner wall of the nacelle. The two air flows are ejected from the turbojet engine from the rear of the nacelle.

 The role of a thrust reverser is, during the landing of an aircraft, to improve the braking capacity thereof by redirecting forward at least a portion of the thrust generated by the turbojet engine. In this phase, the inverter obstructs the cold flow vein and directs the latter towards the front of the nacelle, thereby generating a counter-thrust which is added to the braking of the wheels of the aircraft.

The means implemented to achieve this reorientation of the cold flow vary according to the type of inverter. However, in all cases, the structure of an inverter comprises movable covers movable between, on the one hand, an extended position in which they open in the nacelle a passage intended for the deflected flow, and on the other hand, a position retraction in which they close this passage. These covers can perform a deflection function or simply activation other means of deflection. In the case of a gate inverter, the reorientation of the air flow is performed by deflection grids, the hood having a simple sliding function to discover or cover these grids.

 Moreover, in addition to its thrust reversal function, the sliding cowl has a downstream side forming an ejection nozzle for channeling the ejection of the air flows.

 This ejection nozzle comprises a series of movable panels rotatably mounted at a downstream end of the sliding cover.

 These panels are adapted to, on the one hand, pivot to a position causing a variation of section of the nozzle and, on the other hand, pivot to a position in which, in reverse thrust situation, they come to close the vein in order to deflect the cold flow towards the deflection grids discovered by the sliding of the movable cowl.

 The pivoting of the panels is guided by rods attached, on the one hand, to the panel, and on the other hand, to a fixed point of the internal structure delimiting the annular channel.

 However, the presence of these guide rods passing through the vein causes problems of aerodynamic disturbances but also problems of acoustic performance due to the installation of fixed points of articulation which reduces the surface of the internal structure that can be used for a treatment acoustic and mechanical problems due to the mechanical connection by the links between the thrust reverser and the internal structure.

 Moreover, the actuation kinematics of such a nozzle is complex.

 Indeed, the nozzle being mounted on the movable cowl, the movable panels must be associated with an actuating system allowing, on the one hand, to drive them simultaneously with the movable cowl during the reverse thrust when the cowl is moves to discover the deflection grids and, secondly, to drive them when the hood is in the retracted position to adapt the optimum section of the exhaust nozzle according to the different phases of flight, namely the phases of taking off, cruising and landing the plane.

In such a configuration, there is the essential problem of the kinematics of the degree of opening of the panels relative to the sliding of the hood during the thrust reversal and therefore the management of the total section of the air passage . Indeed, during a transition phase between opening and closing of the thrust reverser, the opening of the panels at the beginning of the opening phase of the movable cowl is faster than the recoil of said cowl.

 There is often a kinematic sensing point which places the panel in partial blocking position of the annular channel without the obstructed section being completely compensated by the upstream section discovered by the recoil of the movable cowl.

 The upstream section of passage through the gates of the inverter is less than the section of the vein which is obstructed by the panels, it follows an increase in the pressure in the engine, which implies a delicate management of the speed of the turbojet in this transitional phase.

 Several solutions have been put in place to solve one or more of these problems.

 Thus, it is necessary to design an inverter architecture no longer comprising a link passing through the annular channel.

 For example, this objective can be achieved by providing a thrust reverser device in which the movable cowl and the panels are associated with actuating means able to activate their respective displacement in translation and in rotation connected to an upstream end of each panel by a driving rod mounted movably around anchor points respectively on the corresponding panel and on the associated actuating means.

 This type of device provides for responding to the particular desired kinematics of the panels of the variable nozzle and the movable cowl using actuating means implementing a certain delay in opening the cowl, in order to allow it to remain fixed. when adjusting the nozzle section.

 It follows that, during the thrust reversal, the panel deploys rapidly in the annular channel from the beginning of the retracting stroke of the sliding cover causing a consequent increase in pressure in the annular channel.

 It does not solve the problem of the proper management of the total section of passage of air in the nacelle.

Consequently, there is a need for improvement of the non-connecting thrust reversal devices in the annular channel in order to overcome the limitations mentioned above. An object of the present invention is to propose a thrust reverser device without a connecting rod in the annular channel in which the opening kinematics of the panels and the sliding cover are controlled during the thrust reversal to ensure a section total exhaust always sufficient compared to the air inlet section.

 It is also desirable to provide a thrust reverser device without a connecting rod in the annular channel in which the kinematics of opening of the panels and the hood are simultaneous, while having an almost constant exhaust air section regardless of its condition of use, in particular in direct jet, in transit and in inverted jet.

 Another object of the present invention is to finely control the nozzle section, without moving the sliding cover from its locking position.

 Another object of the present invention is to provide a rodless thrust reverser device in the annular channel having a simple locking panel drive system while being reliable.

 Another object of the present invention is to provide a thrust reverser device without connecting rod in the annular channel in which the impact of the drive system of the panels on the structure of the movable cowl is limited.

For this purpose, the invention proposes a thrust reverser device for a turbojet engine nacelle comprising, on the one hand, means for deflecting at least part of an air flow of the turbojet engine, and on the other hand on the one hand, at least one cowl movable in translation in a direction substantially parallel to a longitudinal axis of the nacelle, the cowl being able to pass alternately from a closed position in which it ensures the aerodynamic continuity of the nacelle to a position of opening in which it opens a passage in the nacelle for a deflected flow, said movable cover being also extended by at least one variable nozzle section comprising at least one rotatably mounted panel, said panel being adapted for, on the one hand , pivoting towards at least one position causing a variation of the section of the nozzle and, on the other hand, pivoting towards a position in which it obstructs part of an annular channel of the nacelle characterized in that it further comprises a drive train system comprising drive means mounted on the hood and movable along the circumference of the nozzle and a lever assembly pivotally mounted on the cover and articulated at each of its ends, via driving rods, respectively on said drive means and on the panel. With the present invention, it eliminates panel drive rods set up in the vein and the opening kinematics of the panel and hood is controlled to present an air exhaust section in the nacelle almost constant especially when the thrust reverser device is in a start of transit configuration in which the opening of the deflection means by translation of the movable cowl is low.

 According to particular embodiments of the invention, the device may comprise one or more of the following features, taken in isolation or in combination technically possible:

 - The lever assembly comprises a first and a second lever arm, each respectively fixed, via driving rods, on the drive means and on the panel and pivotally mounted on the hood;

 the lever assembly is placed in a plane containing the axis of articulation of the panel and an axis parallel to the longitudinal axis of the device;

 - The first and the second lever arm are integral in rotation;

 the first lever arm has a length greater than that of the second lever arm;

 one of the driving rods is adjustable in length so as to adjust the angle of inclination of the reversing panel to which it is connected;

 the drive means are mounted upstream or downstream of the pivot of the lever assembly;

 - The drive means comprise at least one drive ring mounted on the hood and rotatable about the longitudinal axis of the nacelle;

 the device further comprises means for guiding the drive ring in rotation;

 - The means for guiding the rotation of the drive circuit ring comprise at least one guide rail formed on the cover and centered on the longitudinal axis of the nacelle and / or one or more rotation guide sets secured to the cover. each assembly comprising a guide fitting associated with sliding or rolling elements;

the actuating means capable of actuating the rotational movement of the drive ring comprise at least one actuator extending perpendicularly to the longitudinal axis of the nacelle associated with a transmission shaft extending in parallel to the longitudinal axis of the nacelle, via an angle gear; - The drive means comprise at least one cable mounted on the hood and capable of moving along the circumference of the nozzle, guided by one or more guide pulleys;

 - The actuating means capable of actuating the movement of the cable comprise at least one actuator extending parallel to the longitudinal axis of the nacelle associated with a transmission shaft extending parallel to the longitudinal axis of the nacelle and at least one deflection pulley for transforming a motion of the cable along the longitudinal axis of the nacelle into a movement of the cable in the circumferential direction of the nozzle;

 - The device further comprises motorized means for driving the hood and panels, said motorized drive means being coupled or independent;

 - The motorized drive means of the hood and panels are coupled by a coupling system comprising at least one planetary gear or a mechanical decoupler.

 The invention also relates to a turbofan engine nacelle comprising a thrust reverser device as mentioned above.

Other features, objects and advantages of the present invention will appear on reading the following detailed description, according to embodiments given by way of nonlimiting examples, and with reference to the appended drawings in which:

 FIG. 1 is a perspective view of a thrust reverser device according to a first embodiment of the present invention;

 FIG. 2 is an enlarged view of the zone A of the thrust reverser device of FIG. 1, centered on a drive system of an inversion panel of the device;

 FIG. 3 is an enlarged view of the zone B of the drive system of an inversion panel of FIG. 3;

 FIG. 4 is a perspective view of a thrust reverser device according to a second embodiment of the present invention;

FIGS. 5 to 8 are partial perspective views of the thrust reversal device of FIG. 1 respectively in direct jet configuration, in a transit configuration having two different successive pivoted positions of the thrust reversal panels between lej and di rect and unj and i nversé and in reverse jet configuration; FIG. 9 represents a diagram of the architecture of movable panel actuation means of a thrust reverser device according to FIG. 1;

 FIG. 10 schematizes the operation of a coupling system, of the gear system type, of the engines of a hood and of panels of a thrust reverser device of FIG. 1;

 - Figures 1 1 and 12 show schematically the operation of a coupling system, mechanical decoupler type motors of a hood and panels of a thrust reverser device of Figure 1;

 FIGS. 13 and 14 are respectively partial and entire perspective views of a drive system of a thrust reverser device according to a third embodiment of the present invention.

In a manner known per se, a thrust reverser device designated by the general reference 10 in FIG. 1 is associated with a turbofan engine and belongs to an external nacelle which defines, with a concentric internal structure 1, an annular channel of flow or vein V of a secondary flow of the turbojet engine.

 As illustrated in FIG. 1, the thrust reverser device 10 comprises a stationary front frame 2 extended by a hood 20 slidably mounted by means of slides (not shown) along the longitudinal axis of the nacelle. - Even extended by an ejection nozzle 30 of variable section.

 The front frame 2 supports a plurality of deflection grids (not shown) housed in the thickness of the movable cover 20, when the latter is in the closed position.

 The translation of the movable cowl 20 downstream of the nacelle releases therein an opening through which the secondary jet of the turbojet engine can escape at least partially, this portion of flux being reoriented towards the front of the nacelle by the deflection grids, thereby generating a counter-thrust capable of aiding the braking of the aircraft.

The displacement of the movable cowl 20 along the longitudinal axis of the nacelle is ensured by a set of jacks mounted on the front frame 2 actuated by motorized means, as will be described later in connection with FIG. The ejection nozzle 30, in turn, comprises a series of movable panels 31 rotatably mounted at a downstream end of the movable cowl 20 and distributed over the periphery of the ejection nozzle 30.

 In order to increase the portion of secondary flow passing through the grids, each panel 31 is adapted, on the one hand, to pivot towards a position causing a variation of the section of the nozzle 30 and, on the other hand, to pivot towards a position in which it obstructs the vein V of cold flow and returns this air to the deflection grids which ensure the reorientation of the flow thus allowing the thrust reversal.

 Each panel 31 pivots about its axis of articulation transverse to the longitudinal axis of the nacelle, thanks to ball joints, at its upstream end.

 During operation of the direct thrust turbojet, the sliding cover 20 forms all or part of a downstream part of the nacelle closing the gate opening, the panels 31 then being aerodynamically continuous with the cover 20.

 To reverse the thrust of the turbojet, the sliding cover 20 is moved downstream and the panels 31 pivot in the closed position so as to deflect the secondary flow to the grids and to form an inverted flow guided by the deflection grids.

 Referring to Figures 1 and 2, the thrust reverser device 10 must be equipped with actuating means 40 associated with a system 50 for driving the panels 31 relative to the cover 20 in a suitable kinematic.

 To do this, and according to the invention, the drive system 50 of each panel 31 comprises at least one drive ring 51 mounted on the cover 20, said ring 51 being able to rotate about the longitudinal axis of the nacelle and a lever assembly 60 pivotally mounted on the hood 20 and articulated to ch acu nede its extrem ries, pa rl 1'interm edia biel the drive respectively on the ring 51 and on the panel 31.

 Such a drive system 50 makes it possible to transform the rotational movement of the ring 51 clockwise (and reversibly, anti-clockwise) into a rotational movement of the lever assembly 60, this movement rotation is then returned to actuate the driving rod or rods so as to pivot the panel 31 in a particular position such as a rest position, a thrust reversal position or any transit position between the two aforementioned positions.

In the particular case of thrust reversal, the rotational movement of the ring 51 in the clockwise direction (and reversibly, in the anti-direction time) is actuated in concert with the translation movement of the cowl 20 downstream of the nacelle (and reversibly, upstream of the nacelle), as will be described later in connection with FIG. 9, in particular .

 More specifically, the lever assembly 60 comprises two integral lever arms 61 and 62 forming a generally V-shaped shape, the tip of which is pivotally mounted about a pivot axis X substantially perpendicular to the plane containing the axis of articulation of the inversion panel 31 and parallel to the longitudinal axis of the nacelle, thanks to a hinge fitting 22 integral with the cover 20. In the following description, this plan will be designated as the plane P.

 A first lever arm 61 is fixed to a flange secured to the ring 51 by means of a first link 71 articulated about an axis perpendicular to the plane P, this first link 71 being intended to scan an almost flat surface and parallel to the previously cited plane P.

 The second lever arm 62 is fixed, meanwhile, at one end of a second connecting rod 72 connected at the opposite end to the downstream end of the reversing panel 31.

 At least one of the two driving rods 71, 72 is adjustable in length so as to adjust the inclination angle of the inversion panel 31 to which it is connected to obtain a nozzle 30 of selected section.

 Insofar as the pivot axis X of the lever assembly 60 and the points of attachment of the two lever arms 61, 62 to the corresponding drive rods 71, 72 are placed in the plane P, the stresses in torsion of the lever assembly 60 are reduced.

 To minimize the bulk of the drive system 50 of the inversion panel 31 associated with this constraint, an alternative embodiment then provides to incline the lever assembly 60 a few degrees from the normal to the plane P.

 Furthermore, it should be noted that in order to limit the risks of vibration or vibration and of buckling respectively for the first and the second connecting rod 71, 72, the latter preferably have a thin tubular section, making it possible to provide them with a strong stiffness in flexion.

 Concerning the drive ring 51, it is a circumferential ring mounted between the inner wall and the outer wall of the cover 20, to which the panel 41 is connected by the lever assembly 60.

In a first embodiment illustrated in FIG. 2, it is mounted upstream of the pivot of the lever assembly 60. In a second embodiment illustrated in FIG. 4, it can be mounted downstream of the pivot of the lever assembly 60.

 In the example illustrated in Figure 3, the drive ring 51 has a rectangular general section. However, other types of rings are possible, namely, for example, a ring of cylindrical section.

 This ring 51, mounted free in rotation, is guided in its displacement by a guide rail 71 associated with one or more rotation guide assemblies 70 integral with the cover 20.

 Regarding the guide rail 71, it is shaped on the inner wall of the cover 20 so as to receive in its concavity, the drive ring 51.

 Concerning the rotation guide assemblies 70, each of them comprises a guide fitting 72 and sliding elements 73 arranged on the inner wall of the cover 20.

 The guide fittings 72 are distributed along the circumference of the inner wall of the cover 20.

 They have a female shape complementary to the shape maie of the corresponding drive ring 51.

 In the example illustrated in FIG. 3, they have an inverted U-shaped general section receiving, in the concavity of the U, the corresponding rectangular section of the drive ring 51.

 Each guide fitting 72 is associated with one or more sliding or rolling elements 73 of the type, rollers, bearings or rollers fixed on the guide fitting 72 so as to be interposed between the guide fitting 72 and the drive ring 51.

 The stability of the drive ring 51, when sliding through each guide fitting 72, is ensured because any movement of the ring 51 outside of its rotational movement is prohibited.

 Indeed, the rotation guide assemblies 70 prohibit the translations in the directions of the longitudinal axis of the nacelle and radial and also prevent buckling under load of the drive ring 51.

 To rotate the drive ring 51 about the circumference of the nozzle 30, and therefore that of the lever assembly 60, the thrust reverser 10 comprises the following actuating means 40. .

In general, the actuating means 40 are able, on the one hand, to activate the displacement of the movable cowl 30 in translation along the longitudinal axis of the nacelle as well as the pivoting of each inversion panel 31 to a position where it obstructs the vein V of cold flow during a thrust reversal phase and, secondly, to ensure the pivoting of each panel inversion 31 to a position causing a variation of the section of the nozzle 30, the cover 20 remaining fixed during this nozzle section variation phase 30.

 As illustrated in FIG. 9, the mobile cowl 20 can be translated, in a known manner, under the action of three jacks 23, 24, 25 comprising a central jack 24 and two additional jacks 23 and 25 actuated by motorized means. connected to a control interface (not shown).

 Referring to Figures 1 and 9, concerning the drive ring 51, it is connected by a flange integral with the ring 51 to at least one actuator 41, jack type, extending perpendicular to the longitudinal axis of the nacelle, in the direction of rotation of the drive ring 51, so as to rotate said ring 51.

 This actuator 41 may be in a non-limiting manner a ball or roller cylinder.

 More specifically, the body of the actuator 41 is secured to the movable cover 20 via a cardan (not shown) to allow its rotation. This gimbal is positioned as close as possible to the slideways of the cover 20, so as to transit the resulting forces in the rails of the cover 20.

 More specifically, the central rod of the actuator 41 is intended to be attached to the flange and adapted to be locked in rotation and driven in translation by means of a telescopic transmission shaft 42 associated with the actuator 41.

 In another embodiment, the actuator 41 has its own motorization.

 As illustrated in FIG. 1, the transmission shaft 42 runs along the mast 3 intended to be attached to a fixed part of the aircraft such as a wing, namely extending in the direction of translation of the movable cowl 30 and is connected to the rod of the actuator 41 via a bevel gear type bevel gear 43.

 This transmission shaft 42 is activated by motorized drive means.

In FIG. 9, in one embodiment of the present invention, the drive ring 51 is connected to two actuators 41a, 41b, themselves connected to two transmission shafts 42a, 42b controlled by two drive motors. M1 and M2 independent drive. These drive motors M1 and M2 can be worn by the adre before 2.

 In another embodiment, these drive motor M1 and M2 can be carried by the cover 20 to avoid the need for power transmission shafts.

 Furthermore, the actuators 41 of the drive ring 51 of the inversion panels 31 and the actuating cylinders 23,24,25 of the movable cowl 30 may or may not have the same power drive, namely the power motors. The drives M 1 and M 2 of each transmission shaft 42 associated with the actuators 41 and those of the actuating cylinders 23, 24, 25 of the movable cover 20 may be respectively coupled or independent.

 Whatever the coupling system of the drive motors, the latter are able, on the one hand, to activate the displacement of each transmission shaft 42a, 42b and that of the actuating cylinders 23,24,25 of the cover 20 during a thrust reversal phase and, on the other hand, to activate the displacement of each transmission shaft 42a, 42b and to maintain in the locked position the actuating cylinders 23,24,25 of the cover 20 during a phase of variation of the section of the nozzle 30 of the device 10.

 In a first embodiment, the respective drive motors M1 and M2 of the transmission shafts 42a, 42b are each coupled to that of two actuating cylinders 23, 25 of the cover 20, thanks to at least one drive system. gear 80.

 In a non-limiting example of the first embodiment, this gear system 80 is of the planetary gear type.

 A planetary reducer is known to those skilled in the art and will be described only briefly thereafter.

 With reference to FIG. 1 0, the planetary gear 80 is based on the use of a central gear meshing 81 / satellites 82 / crown 83.

 Each planetary gear 80 thus comprises a rotating central gear 81 centered on the main axis of a driving motor (M1 or M2) to which it is connected, this pinion 81 meshing with several satellites 82 carried, each by axes parallel to the main axis and being secured to a satellite door 84.

These satellites 83 mesh, on the other hand, with the outer ring 83 connected to an actuating cylinder 23 or 25 of the cover 30. One or more additional cylinders 24, necessary for the sliding of the cover 20, may be connected to the cylinders 23 and 25 by a set of flexible shafts 26.

 The satellite gate 84 and the ring 83 are, moreover, associated with independent rotational locking means (not shown).

 The locking in rotation of the ring 83 can be obtained by locking in translation of the rods of the actuating cylinders 23, 24, 25 of the cover 20 corresponding, using locking means (not shown) specific to the latter, lock type known to those skilled in the art.

 In a non-limiting example, the means for locking in rotation of the satellite door 84 comprise, for their part, an obstacle brake.

 Thus, in operation, only one of the two following parts, planet carrier 84 or crown 83 is fixed.

 Each drive motor M1 and M2 is capable of driving the central pinion 81 of a reducer 80 with an input speed ve, this speed being then reduced via the satellites 82 and the ring 83 to provide a speed output vs the element to which is connected either the satellite gate 84 or the ring 83, one of these two parts being then rotatable.

 The operating mode of the thrust reverser device 10 according to the present invention is more precisely the following.

 First, the hood 20 is closed. The thrust reverser device 10 is in jet configuration. The latches of the cover 20 are engaged, as well as the locking of the satellite door 84, so as to prevent any movement of the cover 20 and the inversion panels 31.

 During a nozzle section variation phase, the cover 20 remains fixed.

The locks prohibit the actuation actuating actuators 23, 24, 25 of the cover 20 and block any movement of the cover 20, which keeps active the three lines of defenses preventing the in-flight deployment of the inverter.

 Each drive motor M 1 and M 2 activates the translation movement of the corresponding transmission shafts 42 a, 42 b which cause the activation of the respective actuators 41 a, 41 b, thereby triggering the rotation of the drive ring 51.

As illustrated in FIG. 10, step (b), each driving motor M1 and M2 activates, in parallel, the central pinion 81 of a gearbox 80 which forces the satellites 82 to rotate in the outer ring 83. In their movement, the satellites 82 drive at a reduced speed relative to the driving speed the satellite door 84 whose locking system is deactivated, the outer ring 83 remaining fixed, due to the locked position of the actuating cylinders 23,24 25 of the fixed cover 20.

 On the other hand, the rotational movement of the drive ring 51 causes, via the lever assembly 60, the pivoting of the inverting panels 31 by a few degrees to vary the nozzle section 30.

 During a thrust reversal phase, the actuating cylinders 23, 24, 25 of the cover are unlocked.

 As illustrated in FIG. 10, step (a), each drive motor

M 1 and M2 drives the central pinion 81 of a reducer which forces the satellites 82 to rotate in the outer ring 83.

 In their movement, the satellites 82 drive the crown 83 at a reduced speed with respect to the driving speed because the actuating cylinders 23, 24, 25 of the cover are unlocked, the satellite door 84 remaining stationary due to the locked position of its Lock system.

 The rotation of the ring 83 is converted into a translation movement of an actuating cylinder 23, 24, 25 which drives the cover 20 in translation downstream of the nacelle.

 During this time, each drive motor M1 and M2 activates the respective movement of the transmission shafts 42a, 42b, transmitted to the actuators 41a, 41b connected to the drive ring 51 to drive it in rotation around the longitudinal axis of the nacelle, said ring 51 moving downstream with the cover 20 to which it is attached.

 The pivot axis X of the lever assembly 60, attached to the hood 20, also moves downstream of the nacelle.

 The rotational movement of the drive ring 51 rotates the lever assembly 60 and more, specifically, the first 61 and second 62 lever arms.

 This rotational movement of the first and second lever arms 61, 62 is accompanied by the second drive rod 72, the pivoting of each inversion panel 31 to its closed position of the vein V to the wall internal nozzle 30.

It is necessary to be able to evacuate the air captured by the inlet of the turbojet engine equally in a direct or inverted jet, and more particularly during the thrust reversal during which the reduction of the section of the vein V by the inversion panels 31 must be able to be compensated by increasing the section of the opening offered, upstream of the device 10, by the deflection grids when they are discovered by the translation downstream of the cover 20.

 This particular opening kinematics of the inversion panel 41 and the cover 20 is a function of the ratio of the lever arms 61, 62 of the lever assembly 60 and the angles formed respectively by the first 61 and the second lever arm 62 with the transverse axis of articulation of the reversal panel 30.

 In a non-limiting example of the present invention, the ratio of the lever arms 61, 62 defined as the ratio between the distance from the pivot axis X to the point of attachment of the first connecting rod 71 and the distance from the axis X pivot point at the point of attachment of the second connecting rod 72 is of the order of two but can be modified, if necessary by adjusting the lengths of the lever arms 61, 62.

 Such a ratio of the lever arms makes it possible to transform the race of the ring 51 in rotation into a rotational movement twice as long as to pivot the inversion panel 31.

 Furthermore, the angles formed respectively by the first 61 and the second lever arm 62 with the transverse axis of articulation of the inversion panel 31 are small.

 Thus, the angular displacement of the lever assembly 60 for angular displacement of the given drive ring 51 is limited as is the axial displacement of the second link 62 for the same angular displacement of the lever assembly 60.

 When the thrust reverser device 10 passes from a direct jet configuration to an inverted jet configuration, a progressive pivoting of the inversion panel 31 in the vein V at the beginning of the transit is controlled, when the flow rate air passing through the grids is still low, due to the low degree of opening of the hood 30.

 This minimization of the pivoting of the inversion panel 31 at the beginning of transit ensures that a total air exhaust section is always sufficient with respect to the air inlet section and is almost constant regardless of the configuration of the device 10. especially in reverse thrust configuration.

 Advantageously, each inversion panel 31 is thus adjustable as desired, and therefore adaptable according to the flight phases of the aircraft.

FIGS. 5 to 9 show the thrust reverser device 10 in the so-called transit configuration in which the inversion panel 31 has different pivoting positions between its retracted position and its final position of closing of the vein V.

 More specifically, these figures illustrate a closure of the vein by the inversion panel 31, respectively 0% (the panel is in the direct jet position), 40%, 60% and 100% is in the reverse jet position.

 It should be noted that the previously described operating mode is reversible so that the inversion panels 31 and the cover 20 can move in opposite directions, respectively to their direct jet position and upstream of the nacelle.

 Thanks to the present invention, the opening kinematics of the panel 31 and the cover 20 is isostatic during the thrust reversal, ie at a position of the movable cover 20 corresponds, indirectly, a particular position of the panel inversion 31 to the extent that at an angular position of the drive ring 51 attached to the cover and movable in translation with the cap 20 corresponds to a particular position of the inversion panel 31, while retaining a passage section almost constant air during the pivoting of the panel or panels 31 to their closed position of the vein V, during the reverse thrust.

 In a second embodiment of the present invention, illustrated in FIGS. 9, 11 and 12, the drive motors M1 and M2 of the respective transmission shafts 42a, 42b are coupled, each to that of two jacks. 23,25 actuating the cover 20, with at least one mechanical uncoupler 90.

 Each mechanical decoupler 90 is able, on the one hand, to allow the movement of a transmission shaft 42a, 42b causing the movement of the inversion panels 31 by means of the actuators 41a, 41b so as to traverse the the stroke necessary for the variation of the nozzle section 30 while preventing any translation of the cover 20 during this first stroke and, secondly, to simultaneously drive the transmission shaft 42 and one or more rs actuating cylinders 23,24 Causing the translational movement of the cover 20 beyond the first stroke.

 A decoupler 90 comprises two parallel shafts 91, 92 each connected respectively to a transmission shaft 42 and to a base of an actuating cylinder 23, 24, 25 of the cover 20.

A first shaft 91 also comprises a threaded portion 93, at one end, the length of which is delimited by two stops 94 at the end of the screw thread, the assembly being housed in a grooved cavity 95 adapted to allow the transmission of a torque of the second shaft 92 to a nut 96 carried by the screw 93.

 A set of springs 97 can be placed at the beginning and end of stroke of the screw 93 so as to dampen shocks.

 In operation, as illustrated in FIG. 11, during a nozzle section variation phase 30 (between the two extreme positions of nozzle variation), the screw 93 is not tightened with the nut 96 No torque is transmitted to the first shaft 91 connected to the cover 20, the latter thus remains locked and immobile, the screw 93 running through the space between the stops 94 being driven in rotation by the grooves of the cavity 95.

 At the end of the stroke of the inversion panels 31 in the nozzle section variation phase 30, illustrated in FIG. 12, the nut 96 reaches a stop 94 of thread, preventing its rotation and thus forcing the transmission of torque to first shaft 91 through the splines between the nut 96 and the cavity 95 ..

 The rotational movements of the first and second shafts 91, 92 are transmitted, respectively, to a transmission shaft 42a, 42b activating the translational movement of an actuator 41a, 41b connected to an inversion panel 31 by virtue of the drive ring 51 and an actuating cylinder 23,24,25 connected to the cover 20 to move it downstream of the nacelle, discovering the deflection grids of the flow.

 In a second embodiment illustrated in FIGS. 13 and 14, the thrust reverser device 10 is identical to that described with reference to FIGS. 1 to 12, unlike the following modifications.

 The drive ring 51 is replaced by one or more drive cables 100 capable of moving along the circumference of the nozzle, guided by one or more guide pulleys 1 10 mounted integral on the cover 20.

 Each cable 100 also includes a portion extending along the longitudinal axis of the nacelle through at least one return pulley 11 1 adapted.

 The rotational guide assemblies 70 of the drive ring 51 are therefore suppressed.

 As illustrated more specifically in FIG. 14, the first lever arm 61 of the lever assembly 60 is attached to a guide tube 1 12 of a rod secured to each cable 100 via the first link 61.

Such a drive system makes it possible to transform the movement of the drive cable 100 along the circumference of the nozzle 30 in a clockwise (and reversibly, anti-clockwise) direction in a rotational movement. of the lever assembly 60, this rotational movement being then returned to actuate the driving rod or rods so as to pivot the panel 31 in a particular position such as a rest position, a reversing position of thrust or any so-called transit position between the two aforementioned positions.

 To ensure the pulling of each cable 100 along the circumference of the nozzle, and hence the rotation of the lever assembly 60, the actuating means described above are modified as follows, illustrated in FIG. 13 .

 The actuating means 140 capable of actuating the movement of the cables 100 comprise at least one actuator 141 parallel to the longitudinal axis of the nacelle connected to the portion of each cable 1 00 extending along said axis associated with at least a transmission shaft 142 extending parallel to said axis and at least the aforementioned deflection pulley 1 1 1 capable of transforming a movement of the cable 100 along the longitudinal axis of the nacelle into a movement of the cable 100 in the circumferential direction of the nacelle.

 It should be noted that in a preferred embodiment, two actuators 141 are provided, the two actuators 141 being controlled so as to maintain a voltage in each cable 100 whatever the movement.

 This embodiment offers the advantage of integrating actuators 141 more easily because they are arranged along the longitudinal axis of the nacelle.

 Although the invention has been described with particular examples of embodiment, it is obvious that it is in no way limited and that it includes all the technical equivalents of the means described and their combinations if they enter into the scope of the invention.

Claims

1. Thrust reversing device (10) for a turbojet engine nacelle comprising, on the one hand, means for deflecting at least part of an air flow of the turbojet engine, and on the other hand, at least one hood (20) movable in translation in a direction substantially parallel to a longitudinal axis of the nacelle, the hood (20) being adapted to pass alternately from a closed position in which it ensures the aerodynamic continuity of the nacelle at a position of opening in which it opens a passage in the nacelle for a deflected flow, said movable cover (20) being also extended by at least one variable nozzle section (30) comprising at least one panel (31) rotatably mounted, said panel (31) being adapted to, on the one hand, pivot towards at least one position causing a variation of the section of the nozzle and, on the other hand, to pivot to a position in which it obstructs a portion of an annular channel of the nacelle c characterized in that it further comprises a driving system (50) of the panel including drive means (51, 100) mounted on the hood (20), said driving means (51, 100) being movable along the circumference of the nozzle (30) and a lever assembly (60) pivotally mounted on the hood and hinged at each of its extremities, by means of biel (71, 72) respectively on the drive means (51, 100) and on the panel (31). 2. Device according to claim 1 characterized in that the lever assembly (60) comprises a first and a second lever arm (61, 62), each respectively fixed, via driving rods, on the driving means (51, 100) and on the panel (31) and pivotally mounted on the cover (20). 3. Device according to one of claims 1 to 2 characterized in that the lever assembly (60) is placed in a plane containing the axis of articulation of the panel (31) and an axis parallel to the longitudinal axis of the device (10). 4. Device according to one of claims 2 to 3 characterized in that the first and the second lever arm (61, 62) are integral in rotation. 5. Device according to one of claims 2 to 4 characterized in that the first lever arm (61) has a length greater than that of the second lever arm (62). 6. Device according to one of claims 1 to 5 characterized in that one of the driving rods (71, 72) is adjustable in length to adjust the angle of inclination of the inversion panel 31 which she is connected. 7. Device according to one of claims 1 to 6 characterized in that the drive means (51, 100) are mounted upstream or downstream of the pivot of the lever assembly (60). 8. Device according to one of claims 1 to 6 characterized in that the drive means (51, 100) comprise a drive ring (51) mounted on the cover (20) and capable of rotating around the longitudinal axis of the nacelle. 9. Device according to claim 8 characterized in that it further comprises means for guiding the rotation of the drive ring (51). 10. Device according to claim 9 characterized in that the means for guiding the rotation of the drive ring (51) comprise at least one guide rail (71) formed on the cover (20) and centered on the axis longitudinal assembly of the nacelle and / or one or more sets of rotation guide (70) integral with the cover (20), each assembly comprising a guide fitting (72) associated with sliding or rolling elements (73). 1 1. Device according to one of claims 8 to 10 characterized in that the actuating means capable of actuating the rotational movement of the drive ring (51) comprise at least one actuator (41) extending perpendicularly to the longitudinal axis of the nacelle associated witha rbre transmission (51) extending parallel to the longitudinal axis of the nacelle, via a bevel gear (43). 12. Device according to one of claims 1 to 6 characterized in that the drive means (51, 100) comprises a drive cable (100) mounted on the cover (20) and capable of moving along the the circumference of the nozzle, guided by one or more guide pulleys (1 10). 13. Device according to claim 12 characterized in that the actuating means capable of actuating the movement of the cable (100) comprise at least one actuator (41) extending parallel to the longitudinal axis of the nacelle associated with a transmission shaft (51) extending parallel to the longitudinal axis of the nacelle and at least one deflection pulley for transforming a movement of the cable (100) along the longitudinal axis of the nacelle into a movement of the cable (100) in the circumferential direction of the nozzle. 14. Device according to one of claims 1 to 13 characterized in that it further comprises motorized drive means (M1 and M2) of the cover (20) and panels (31), said motorized means of being coupled or independent. 15. Device according to claim 14 characterized in that motorized drive means (M1 and M2) of the cover (20) and panels (31) are coupled by a coupling system comprising at least one planetary reducer or a mechanical decoupler. . 16. A turbofan engine nacelle comprising a thrust reverser device according to one of claims 1 to 15.