EP2572097A1

EP2572097A1 - Airplane jet engine thrust reverser having gratings or cascades

Info

Publication number: EP2572097A1
Application number: EP11725145A
Authority: EP
Inventors: Guy Bernard Vauchel
Original assignee: Aircelle SA
Current assignee: Safran Nacelles SAS
Priority date: 2010-05-17
Filing date: 2011-05-10
Publication date: 2013-03-27
Also published as: CN102893010A; RU2012153437A; BR112012027593A2; WO2011144837A1; US9109540B2; US20130075493A1; CA2798484A1; FR2960029B1; FR2960029A1; CN102893010B; RU2570482C2

Abstract

Said thrust reverser, having gratings and intended for an airplane dual flow jet engine nacelle, includes: a front frame (9) holding a plurality of cascades (7); a cowl (13) that is slidably mounted between a direct jet position, in which said cowl covers said cascades (7), and a reverse jet position, in which said cowl uncovers said cascades (7), said cowl (13) including a substantially annular diaphragm (17) that is placed edge-to-edge with said front frame (9) and radially inside said cascades (7) when said cowl (13) is located in a direct jet position; - thrust reversal flaps (31) that are pivotably mounted onto said diaphragm (17) between a direct jet position, in which said flaps enable the flow of cool air downstream from the thrust reverser, and a reverse jet position, in which said flaps direct said cool air (F2) to said cascades (7); and cylinders (19) for actuating said cowl (13) between the direct and reverse jet positions thereof. Said thrust reverser is characterized in that the upstream ends of said cylinders (19) are to intended be mounted onto a stationary portion of said nacelle and in that the downstream ends of said cylinders are mounted onto the upstream edge (27) of said diaphragm (17).

Description

Grid or cascade thrust reverser for an airplane turbojet engine

The present invention relates to a thrust reverser grid or cascade for an aircraft turbojet.

An aircraft is driven by several turbojet engines each housed in a nacelle also housing a set of ancillary actuating devices 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.

More specifically, 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 reversal means and intended to surround the engine room. combustion of the turbojet, 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 through the blades of the rotating fan a flow of hot air (also called primary flow) from the combustion chamber of the turbojet engine, and a flow of cold air (secondary flow) flowing outside the turbojet through an annular channel, also called vein, formed between a fairing 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 annular channel of the cold air flow 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 used to achieve this reorientation of the cold air flow vary according to the type of inverter. However, in all cases, the structure of an inverter comprises movable covers moved between, on the one hand, an extended position (or "reverse jet") in which they open in the nacelle a passage for the deflected flow, and secondly, a retracted position (or "direct jet") in which they close this passage.

In the case of a gate inverter, also known as a cascade inverter, the reorientation of the air flow is performed by deflection grids, the hood being slidably mounted along the axis of the nacelle. to discover or cover these grills. Complementary locking doors, also called inversion flaps, activated by the sliding of the cowling, generally allow closure of the annular channel of cold air flow downstream of the grids so as to optimize the reorientation of this air flow.

The sliding of the mobile cowl between its "direct jet" and "reverse jet" positions is ensured by cylinders distributed around the periphery of the nacelle.

Conventionally, these cylinders are fixed upstream on a fixed part of the nacelle, such as the front support frame of the deflection grilles, and downstream inside the movable cowl, through suitable fittings.

More specifically, the actuating rods of these cylinders pass through the rear support frame of the deflection grids to cooperate with the movable cowl.

This necessarily implies that the rear frame of the deflection grilles has a certain radial size.

Or in modern nacelles, where one seeks to reduce the aerodynamic losses due to wet surfaces, lines are increasingly collected, and it is therefore important in particular to be able to reduce the radial thickness of the rear frame.

The present invention is thus particularly intended to provide means for reducing the thickness of the rear support frame of the deflection grids.

This object of the invention is achieved with a thrust reverser with gates for a jet aircraft turbojet engine nacelle comprising:

a front frame supporting a plurality of deflection grids,

a cover mounted sliding between a direct jet position in which it covers said grids and a reverse jet position in which it discovers these grids, this cover comprising a substantially annular diaphragm coming to be placed edge to edge with said front frame and radially to inside said grids when said hood is in the direct jet position, - Reversing thrust flaps mounted pivoting on the diaphragm led between a jet position d irect in which they allow the circulation of cold air downstream of the inverter, and a reverse jet position in which they direct this cold air towards said grids, and

actuating cylinders of said cover between its direct jet and reverse jet positions,

this thrust reverser being remarkable that the upstream ends of said jacks are intended to be mounted on a fixed part of said nacelle, and in that the downstream ends of these jacks are mounted on the upstream edge of said diaphragm.

With these features, the cylinders do not have to go through the rear support frame of the deflection grids, since the diaphragm is located radially inside (that is to say under) this frame.

In this way, it is possible to minimize the thickness of this rear frame, and thus reduce the thickness of the movable cowl.

Moreover, as the cylinders are in the extension of the diaphragm, it does not increase the congestion in the area located radially inward (that is to say, under) this diaphragm.

Note also that the arrangement according to the invention is also suitable when the reversing gates are self-supporting, that is to say when there is no rear frame, and the gates are only fixed between them and on the front frame.

According to other optional features of this thrust reverser according to the invention:

said cylinders are located under said grids;

said cylinders are located between said grids;

the axes of these cylinders are located in the diaphragm alignment: this particular arrangement allows an optimal distribution of the forces;

said diaphragm comprises an upstream edge folded towards the inside of the nacelle, supporting fittings for fixing the downstream ends of said jacks;

said upstream edge also supports a seal capable of being pressed against said front frame when said movable cowling is in the direct jet position advantageously under the jack; said front frame comprises an annular groove provided with a seal, and the upstream edge of said diaphragm comprises a skirt adapted to fit in this groove when said movable cover is in a direct jet position;

- It it frame before com door cavities adapted to receive the downstream ends of said cylinders, and at least a portion of said fittings, when said movable cover is in the direct jet position.

The present invention also relates to a nacelle incorporating a thrust reverser according to the above.

Other characteristics and advantages of the present invention will emerge in the light of the description which follows, and on examining the appended figures, in which:

FIG. 1 shows, in axial section, the zone of the inversion gates of a thrust reverser according to the invention, when this inverter is in the direct jet position;

FIG. 2 represents this inverter in reverse jet position;

FIG. 3 represents another mode of realisation of this inverter according to the invention, in the direct jet (continuous lines) and reverse jet (dotted line) positions respectively, and

- Figure 4 shows yet another embodiment of the inverter according to the invention, in the reverse jet position.

In all of these figures, identical or similar references denote identical or similar members or sets of members.

Referring now to Figures 1 and 2, on which we can see a thrust reverser grids according to the invention, disposed downstream of the fan casing 3 of a turbofan engine, and its fan cover 5 associated.

This thrust reverser according to the invention comprises a plurality of deflection grids 7, fixed between a front frame 9 and a fixed rear frame 1 1.

A movable cover 1 3, comprising an outer panel 15 and an inner diaphragm 17, is slidably mounted between a position in which this panel and this diaphragm cover the deflection grids 7 (FIG), and a reverse jet position, in which this panel 1 5 and this diaphragm 1 7 discover these grids 7 (Figure 2). Actuation of the movable cowl 13 between these two positions is effected by a plurality of jacks 19 disposed at the periphery of the nacelle, and whose body 21 is fixed upstream of the front frame 9, and whose actuating rod 23 co-operates with the inner diaphragm 17 via a fitting 25.

More specifically, the inner diaphragm 17 comprises, in its upstream part, an edge 27 folded towards the inside of the nacelle, that is to say in the direction of the axis A of this nacelle.

The upstream edge 27 of the diaphragm 17 supports a seal 29 adapted to be pressed against the front frame 9 when the movable cover 13 is in the direct jet position, as shown in FIG.

A plurality of thrust reverser flaps 31 are moreover pivotally mounted on the diaphragm 17, between a direct jet position (FIG. 1) in which they provide continuity and dynamics with the inner wall 33 of the movable cowl 13, and a reverse jet position (Figure 2) in which they seal the cold air duct 35 delimited by the inner wall 33 of the movable cowling 13 and the fairing (often referred to as IFS: "Internai Fixed Structure") surrounding the turbojet engine ( not shown).

Note that the actuation of the thrust reversing flaps

31 is performed by connecting rods 39 interposed between these flaps and the fairing 37. Similarly the concept can adapt to any concept of driving flaps without connecting rod in the vein.

The mode of operation and the advantages of the thrust reverser, the main elements of which have just been described, are as follows.

In a direct jet situation (FIG. 1), the flow of cold air circulates inside the vein 35, along the arrow F1, towards the downstream end of the nacelle, making it possible to carry out the thrust required for the flight of the plane.

In reverse jet position (Figure 2), the rods 23 of the cylinders 19 out of the body 21 of these cylinders, sliding the movable cowl 13 downstream of the nacelle, which has the effect on the one hand to discover the inversion gates 13, and secondly, to tilt the inversion flaps 31 to a position in which they close the cold air duct 35, under the action of their respective connecting rods 39. This operation has the effect of deflecting the flow of cold air, circulating inside the vein 35 through the inversion grids 7, towards the front of the nacelle, as indicated by the arrow F2.

This air deflection towards the front of the nacelle causes braking of the aircraft during landing.

The fact that the cylinders 1 9 are placed so that their actuating rods 23 cooperate with the inner diaphragm 1 7 of the movable cover 1 3 makes it possible to overcome the need to cross the rear frame 1 1 by these rods 23, as was the case in the prior art.

One can thus have a rear frame whose radial thickness e is minimal, given the lack of need to provide orifices and festonnages in this frame.

One can even consider to completely do without such a frame, in particular applications where the deflection grids 7 are self-supporting, that is to say, fixed only to the front frame 9 and between them.

It will further be noted that the cooperation of the rods 23 of the cylinders 19 with the internal diaphragm 17 also avoids cluttering with these rods the space below (that is to say radially inside) this diaphragm.

As can be seen in FIG. 2, the geometry of the fittings 25 is studied so that in the direct jet position they are placed just upstream of the rear frame 11, without interfering with it.

Preferably, the axis desd its cylinders 1 9 is s itu é s s the exact extension of the inner diaphragm 17, so as to ensure an optimal distribution of efforts.

As shown in Figure 1, it is expected that the front frame 9 comprises housings, that is to say openings adapted to accommodate the fitting 25 when the movable cover 13 is in the direct jet position.

In this position, the seal 29, compressed between the upstream edge 27 and the front frame 9, makes it possible to guarantee the perfect seal of the cold airstream 35 vis-à-vis the outside, and thus to avoid any loss of thrust.

The embodiment of FIG. 3 differs from the preceding one essentially in that the seal 29 is now disposed inside an annular groove formed inside the front frame 9, the upstream edge 27 of the inner diaphragm 17 then comprising in this case, a skirt 43 adapted to fit into the groove 41, and therefore to compress the seal 29 in the direct jet position. In the embodiment of FIG. 4, it can be seen that the jack 19 can be arranged slightly more towards the outside of the nacelle, to the point that it interferes with the volume defined by the deflection grid 7: in this case, spaces are provided between the deflection grids 7, so as to allow the passage of the actuating rod 23 of the jack 19.

The fitting 25 is then of course shaped so as to allow the correct attachment of the end of the actuating rod 23 of the jack with the upstream edge 27 of the inner diaphragm 17.

Of course, the present invention is not limited to the embodiments described and shown, provided as simple examples.

Claims

1. A thrust reverser for grids for a jet aircraft turbojet engine nacelle, comprising:

a front frame (9) supporting a plurality of deflection grids (7),

- A cover (1 3) slidably mounted between a direct jet position in which it covers said grids (7) and a reverse jet position in which it discovers these g ril (7), the hood (1 3) comprising und ragme Substantially annular (1 7) being placed edge to edge with said front frame (9) and radially inside said grids (7) when said cover (13) is in the direct jet position,

- thrust reversing flaps (31), pivotally mounted on said diaphragm (1 7) between a direct jet position in which they allow the cold air flow (F1) downstream of the inverter, and a reverse jet position in which they direct this cold air (F2) towards said grids (7), and

actuators (1 9) for actuating the hood (1 3) between its direct jet and reverse jet positions,

this thrust reverser being characterized in that the upstream ends of said jacks (19) are intended to be mounted on a fixed part of said nacelle, and in that the downstream ends of these jacks are mounted on the upstream edge (27) of said diaphragm (17).

2. thrust reverser according to claim 1, characterized in that said jacks (19) are located under said grids (7).

3. thrust reverser according to claim 1, characterized in that said cylinders (19) are located between said grids (7).

4. thrust reverser according to claim 2, characterized in that the axes of said cylinders (19) are located in alignment with said diaphragm (17).

5. thrust reverser according to claim 1, characterized in that said diaphragm (17) comprises an upstream edge (27) folded towards the inside of the nacelle, supporting fittings (25) for fixing the downstream ends of said cylinders (19). ).

6. thrust reverser according to claim 5, characterized in that said upstream edge (27) further supports a seal (29) adapted to be pressed against said front frame (9) when said movable cover (1 3). is in the direct jet position.

7. thrust reverser according to claim 5, characterized in that said front frame (9) comprises an annular groove (41) provided with a seal (29), and the upstream edge (27) of said diaphragm comprises a skirt (43) adapted to fit into this groove (41) when said movable cover (13) is in the direct jet position.

8. thrust reverser according to claim 1, characterized in that said front frame (9) comprises cavities adapted to receive the downstream ends of said cylinders (19), and at least a portion of said fittings (25), when said movable hood (13) is in the direct jet position.

9. Aircraft turbofan engine nacelle comprising a thrust reverser according to any one of the preceding claims.