THRUST REVERSER FOR AN AIRCRAFT BYPASS TURBOJET ENGINE NACELLE

Abstract

A thrust reverser for an aircraft bypass turbojet engine nacelle has a generally annular shape around an axis and includes an annular frame for securing deflection grids. The frame has a first frusto-conical wall widening in the downstream direction and including an upstream peripheral edge configured to be attached to a casing of the turbojet engine. A downstream peripheral edge of the wall extends in the continuation of the wall and secures the upstream ends of the grids. A second annular wall extends radially outwards from an outer frusto-conical face of the first wall. The first and second walls are integrally formed and the second wall has axial openings through which actuators pass.

Claims

1. A thrust reverser for a nacelle of an aircraft bypass turbojet engine, the thrust reverser having an annular shape around an axis and comprising: a fixed upstream part comprising an annular frame, a downstream annular support, deflection grids, upstream ends of which are secured to said frame and downstream ends of which are secured to said support, cowls configured to be moved in translation from an upstream position in which the cowls cover the grids to a thrust reversal downstream position in which the grids are uncovered, elements configured to deflect a secondary flux (F11) of the turbojet engine through the grids when the cowls are in the downstream position, and actuators of elongated shape, upstream ends of which are secured to the fixed part and downstream ends of which are secured to said cowls, wherein the frame comprises: a first frustoconical wall widening in a downstream direction and comprising an upstream peripheral edge configured to be secured to a casing of the turbojet engine, and a downstream peripheral edge extending in a continuation of the wall and securing the upstream ends of the grids, and a second annular wall extending radially outwards from an external frustoconical face of said first wall, said first and second walls being integrally formed and said second wall comprising axial orifices through which said actuators pass.

2. The thrust reverser according to claim 1, wherein said actuators extend parallel to said axis.

3. The thrust reverser according to claim 1, wherein each of said grids extends in a plane (P) which is inclined by an angle (a) comprised between 5° and 20° with respect to said axis.

4. The thrust reverser according to claim 2, wherein each of said actuators extends between two adjacent grids and each passes through the planes (P) of the two adjacent grids.

5. The thrust reverser according to claim 1, wherein said actuators have downstream ends remotely surrounded by said support.

6. The thrust reverser according to claim 1, wherein said second wall has an upstream face comprising first recesses and a downstream face having second recesses, said orifices being formed at a bottom of said first recesses.

7. The thrust reverser according to claim 6, wherein at least two partitions parallel to each other and to said axis extend in each of said first recesses, the partitions being connected to the bottom of the respective first recess and being disposed on either side of said orifice.

8. The thrust reverser according to claim 7, wherein the actuators are secured to said partitions.

9. The thrust reverser according to claim 6, wherein said second recesses are formed by a multitude of cavities defined by first annular webs and second radial webs.

10. The thrust reverser according to claim 1, wherein the frame comprises a third annular wall which extends radially inwards from an internal frustoconical face of said first wall, stiffening ribs extending radially between the internal frustoconical face and a downstream annular face of the third wall.

11. The thrust reverser according to claim 10, wherein an annular deflection fairing bears on and is secured to an internal periphery of said third wall and on a downstream end of said internal frustoconical face.

12. A bypass turbojet engine for an aircraft, comprising a thrust reverser according to claim 1.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0046] The present invention will be better understood and further details, features and advantages of the present invention will become clearer from the following non-limiting example description, with reference to the attached drawings in which:

[0047] FIG. 1 is a partial schematic view, in longitudinal section, of a thrust reverser according to the prior art in the direct jet position;

[0048] FIG. 2 is a partial schematic view, in longitudinal section, of the thrust reverser of FIG. 1 in the reverse thrust position;

[0049] FIG. 3 is a partial schematic view, in longitudinal section, of another thrust reverser according to the prior art in the reverse thrust position;

[0050] FIG. 4 is a larger scale view of part of the thrust reverser of FIG. 3;

[0051] FIG. 5 is a partial schematic view, in longitudinal section, of a thrust reverser according to one embodiment of the invention in the direct jet position;

[0052] FIG. 6 is a partial schematic view, in longitudinal section, of the thrust reverser of FIG. 5 in the reverse thrust position;

[0053] FIG. 7 is a larger scale view of part of the thrust reverser of FIG. 5;

[0054] FIG. 8 is a partial schematic view, in longitudinal section, of the thrust reverser frame of FIG. 5;

[0055] FIG. 9 is a partial schematic perspective view of the thrust reverser of FIG. 5, viewed from downstream;

[0056] FIG. 10 is a partial schematic perspective view of the thrust reverser of FIG. 5, viewed from upstream;

[0057] FIG. 11 is a partial schematic perspective view of the thrust reverser frame of FIG. 5, viewed from upstream; and

[0058] FIG. 12 is a partial schematic perspective view of the thrust reverser frame of FIG. 5, viewed from the downstream.

DETAILED DESCRIPTION OF THE INVENTION

[0059] Reference is now made to FIGS. 5 to 12 which illustrate a preferred embodiment of a thrust reverser 30 according to the invention for an aircraft turbojet engine nacelle.

[0060] The thrust reverser 30 has a generally annular shape about an axis (not visible) which is the longitudinal axis of the turbojet engine and its nacelle. The thrust reverser 30 comprises: [0061] a fixed upstream part 32 comprising an annular frame 34, [0062] a downstream annular support 36, [0063] deflection grids 38, the upstream ends of which 38a are secured to the frame 34 and the downstream ends of which 38b are secured to the support 36, [0064] cowls 40 which can be moved in translation from an upstream position shown in FIG. 5, in which they cover and enclose the grids 38, to a thrust reversal downstream position shown in FIG. 6, in which the grids 38 are uncovered and therefore free, [0065] elements 42 for deflecting the secondary flux F11 of the turbojet engine through the grids 38 when the cowls 40 are in their downstream position, and [0066] actuators 44 of elongated shape, the upstream ends 44a of which are secured to the fixed part 32 and the downstream ends 44b are secured to the cowls 40.

[0067] The deflection elements 42 may comprise flaps 46 associated with connecting rods 48, as in the prior art.

[0068] The cowls 40 may be similar to those of the prior art and will not be further described.

[0069] The actuators 44 are preferably cylinders. There are, for example, two or more of them, evenly distributed around the axis of the reverser. Each reverser 44 comprises a fixed body 44c and a movable rod 44c. In the example shown, the body 44c is secured to the fixed part 32 and the rod 44d is secured to the cowl(s) 40. It is therefore understood that it is the upstream end 44a of the body 44c that is secured to the fixed part 32, and the downstream end 44b of the rod 44c is secured to the cowl(s).

[0070] The attachment of the rod 44d to the cowl(s) 40 is achieved here by a clevis 50 added and secured to the cowl(s) 40. The attachment of the body 44c will be described in more detail in the following.

[0071] The deflection grids 38 are similar to those of the previous technique except that, in the example shown, they each extend in a plane P which is inclined at an angle α of between 5° and 20° with respect to the axis of the reverser (FIG. 6).

[0072] It can be seen that the planes P of the grids 38 are traversed by the actuators 44. As can be seen in FIGS. 9 and 10 in particular, each of the actuators 44 passes between the facing longitudinal edges of two adjacent grids 38. The grids 38, arranged on either side of an actuator 44, are therefore circumferentially spaced apart to provide a passage for the actuator. The adjacent grids 38 which are not arranged on either side of an actuator are instead arranged circumferentially edge to edge.

[0073] The support 36 preferably extends continuously through 360° around the axis of the reverser 30. It is formed by a ring in the example shown.

[0074] The downstream ends 38b of the grids 38 are applied to an external annular face 36a of the support 36 and are secured to the support by welding or by securing means of the screw-nut type for example (FIG. 10).

[0075] It can be seen that the support 36 extends around the actuators 44. FIGS. 5 and 6 show that the actuators 44 are located at a certain distance from this support 38. The upstream ends 38a of the grids 38 are applied to an external frustoconical face 52c of the frame 34 and are secured to this frame by welding or by securing means of the screw-nut type for example (FIG. 7).

[0076] The frame 34 is only visible in axial section in FIG. 8 and in perspective in the following figures.

[0077] The frame 34 comprises: [0078] a first frustoconical wall 52 widening in the downstream direction and comprising an upstream peripheral edge 52a and a downstream peripheral edge 52b which extends in the continuation of the wall 52 and which comprises the aforementioned face 52c, and [0079] a second annular wall 54 which extends radially towards the outside from this face 52c.

[0080] According to one of the characteristics of the invention, the walls 52, 54 and even other walls of the frame 34 are integrally formed (or come as a whole of material). Indeed, one of the aims of the invention is to produce a one-piece frame 34 eliminating any need for assembly of parts. The frame 34 is for example made of aluminium.

[0081] The frame may be continuous over 360° or may be sectorised into two or more consecutive sectors.

[0082] In the context of the present invention, the frame 34 may be made by machining a block of material. The block of material may be in the form of a plate which is cut to obtain an annular shape, the internal and external diameters of which correspond to the internal diameter Dint and external diameter Dext of the frame, to within a few millimetres, for example, in order to allow finishing machining. This plate has a maximum thickness which corresponds to the maximum axial dimension Emax1 of the frame. Emax1 is for example between 150 and 250 mm, and preferably between 200 and 220 mm. This block or plate is then intended to be machined to form the walls 52, 54 and other parts of the frame which will be detailed in the following.

[0083] In the example shown, the frame 34 includes a third annular wall 56 which extends radially towards the inside from an internal frustoconical face 52d of the wall 52.

[0084] This wall 56 is also formed integrally with the walls 52, 54.

[0085] In the example shown, the wall 56 is generally inverted L-shaped in cross-section and comprises a radially external annular leg 56a, the external periphery of which is connected to face 52d and the internal periphery of which is connected to an annular flange 56b which is here oriented axially upstream. The leg 56a would have a generally frustoconical shape flaring from downstream to upstream.

[0086] An annular deflection fairing 58 is supported and secured on one side on the flange 56b and on a downstream end of the face 52d. The fairing 58 comprises a downstream end portion 58a which is planar and is applied to the face 52d, the remainder of the fairing being domed or curved with a concavity directed radially towards the outside and upstream.

[0087] As can be seen in FIG. 7, this downstream end portion 58a of the fairing 58 is located radially towards the inside of the actuators 44 and is therefore not interrupted by any passages required for those actuators.

[0088] From the same figure it can be seen that the upstream ends of the grids 38 are parallel to this downstream end portion 58a. This is due to the fact that the downstream edge 58b of the wall 52 extends in the continuation of this wall and therefore has a frustoconical shape, the internal 52d and external 52c faces of which are parallel when viewed in cross-section.

[0089] The opposite upstream edge 52a of the wall 52, known as the J-ring, has a specific cross-sectional shape which allows it to be secured to a turbojet engine casing, as is well known to the person skilled in the art.

[0090] The wall 54 has a relatively large axial thickness Emax2 and is recessed on its two faces 54a, 54b by machining (FIGS. 8 to 10). The wall 54 thus comprises an upstream face 54a comprising first recesses 60 (FIGS. 10 and 11), and a downstream face 54b having second recesses 62 (FIGS. 9 and 12).

[0091] In the example shown, there are as many recesses 60 as there are actuators 44 because each actuator is intended to pass through an orifice 64 formed in the bottom 60a of a recess 60.

[0092] Each recess 60 is generally parallelepipedic in shape and is open axially upstream. In the example shown, the recess 60 is divided into three parts by two partitions 66 which are parallel to each other and to the axis of the reverser. The partitions 66 are connected to the bottom 60a of the recess 60 and are arranged on either side of the orifice 64. In the radial direction, they further extend between the face 52c and the external periphery of the wall 54.

[0093] The actuators 44 are secured to these partitions 66 which may comprise two aligned orifices 68 for receiving and securing a shaft (not shown) of the actuator 44. Each actuator 44 and in particular its end 44a or its cylinder 44c is secured to the frame 34 and more particularly to partitions 66 of the frame.

[0094] The recesses 62 enables to lighten the frame 34 while guaranteeing its mechanical strength. For this purpose, the recesses 62 of the downstream face 54b may take the form of a multitude of cavities defined by first annular webs 68 and second radial webs 70, as can be seen in FIG. 12. It can also be seen from FIG. 12 that the frame 34 includes stiffening ribs 72 which extend radially between the internal frustoconical face 52d and a downstream annular face 56c of the wall 56.

[0095] The construction of the frame 34 in a single piece brings several advantages mentioned above. In particular, it avoids the assembly of parts. It also allows several functions to be integrated into this frame, in particular securing to the casing by the edge 52a, securing to the grids by the edge 52b, passing the actuators 44 through the orifices 60 of the wall 54, securing the actuators 44 by the partitions 66, lightening and reinforcing the frame 34 by the webs 68, 70 and the ribs 72, etc.

[0096] The alignment of the grids 38 in the continuation of the frustoconical wall 52 is also advantageous because it optimises the flow of the secondary flux F11 through the grids in the reverse thrust position. It allows the upstream ends 38a of the grids 38 to be brought closer to the downstream end of the fairing 58 and therefore to guide the flux just after it leaves the fairing, thus limiting the risks of air separation on the latter. It is then possible to reduce the axial dimension of this fairing to further limit this risk of detachment.