WO2012104561A2

WO2012104561A2 - Nacelle with articulated fan casing covers

Info

Publication number: WO2012104561A2
Application number: PCT/FR2012/050231
Authority: WO
Inventors: Guy Bernard Vauchel
Original assignee: Aircelle
Priority date: 2011-02-04
Filing date: 2012-02-02
Publication date: 2012-08-09
Also published as: FR2971231A1; WO2012104561A3

Abstract

This aircraft propulsion assembly comprises a nacelle (1) and a turbojet engine, said nacelle comprising an intermediate part (7) and said turbojet engine comprising a fan casing (19) located inside said intermediate part (7), said intermediate part (7) comprising two fan casing half-covers (17b) each able to move about substantially longitudinal axes situated at the upper part of said nacelle, between a closed position in which they cover said casing (19) and an open position in which they allow the periphery of this casing (19) to be accessed, the propulsion assembly being characterized in that said covers (17b) are articulated at least in part directly to said propulsion assembly.

Description

Nacelle with articulated fan case hoods

The present invention relates to a propulsion unit for an aircraft, comprising a nacelle and a turbojet engine.

As is known per se, and visible in FIGS. 1 and 2, a propulsion unit for an aircraft conventionally comprises a nacelle 1 and a turbojet engine, this nacelle typically comprising an upstream part 5 forming an air inlet, an intermediate part 7 surrounding the fan 9 of a turbojet engine, and a downstream portion 1 1 in which is the engine 3 of the turbojet engine.

This rear portion may typically incorporate thrust reversal means.

Conventionally, the assembly that has just been described is suspended under the wing 13 of an aircraft by means of a connecting member called mast or pylon 15.

On this mast 15 are articulated two half-cowlings 17a, 17b of fan, between a normal closed position (solid line in Figure 2) in which they cover the intermediate portion 7 of the nacelle 1, and an open maintenance position ( dashed lines in Figure 2) in which they allow access to the bodies which are mounted on the periphery of the casing 19 of the fan 9.

In addition to its suspension function, such a mast allows the passage of electrical cables, hydraulic conduits, fuel supply conduits of the engine 3, etc.

In new generation nacelles, the amount of cables and conduits to be passed through the mast 15 is substantially reduced, in particular because of the progressive replacement of hydraulic systems by electrical systems, such as the actuation systems of the thrust reversers.

One consequence of this evolution is a significant reduction in the section of the mast, which is positioned essentially - or only on the rear part 1 1 of the nacelle 1, as can be seen in FIG.

It is understood that with this new configuration arises the problem of the articulated assembly of the two half-cowls 17a, 17b of fan, the latter can not indeed be performed on the mast 15. The present invention thus aims in particular to provide a solution for mounting the fan cowls in these new generation nacelles.

This object of the invention is achieved with a propulsion unit for an aircraft, comprising a nacelle and a turbojet, said nacelle comprising an intermediate part and said turbojet having a fan casing located inside said intermediate part, said intermediate part comprising two half-covers each movable about substantially longitudinal axes located in the upper part of said nacelle, between a closed position in which they cover said housing and an open position in which they allow access to the periphery of the housing, said half cap assemblies being articulated on fixed elements chosen from the group comprising:

at least one internal partition of said nacelle, and

- Support means formed integrally with said fan casing.

"Propulsion unit" means, in the context of the present invention, the assembly formed by the nacelle and its turbojet engine, excluding the suspension mast of this assembly under the wing of the aircraft.

Thanks to the characteristics of the invention, it is possible to dispense with the suspension mast of the propulsion unit, the articulation of the two movable half-covers being carried out on the propulsion unit itself: this articulation is possible in particular when the suspension mast cooperates only with the downstream part of the nacelle.

The fixed elements of the nacelle or turbojet have a sufficient rigidity to support the weight and movements of the two half-covers.

According to other optional features of the present invention, taken alone or in combination:

- The hinge means comprising integral fittings respectively of the partition and said covers, and pins cooperating with these fittings allowing their rotary movements relative to each other;

the support means comprise a support leg extending over the entire length of said half-covers; said support means comprise a plurality of support legs, separated from each other along the length of said half-covers;

- Sealing means are interposed between the two contiguous edges of the two dem i-covers, these means being selected from the group comprising seals and a sealing channel;

said seals are fixed on angles disposed on the inner faces of said half-covers.

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 represents, in side view, a classically propulsive assembly, including a nacelle and a rboreactor, suspended under an aircraft wing, such a conventional assembly having been described in the preamble of FIG. DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 represents a front view of this conventional assembly,

FIG. 3 represents a propulsion unit comprising a nacelle and a new-generation turbojet, as mentioned in the preamble of the present description, suspended under the wing of an aircraft by means of a mast cooperating with the downstream part of the nacelle,

FIG. 4 represents a detail view, in longitudinal section, of zone Z1 of FIG. 3, for a first embodiment of the invention,

FIG. 5 represents a view similar to that of FIG. 4, for a second embodiment of the invention,

FIG. 6 represents a sectional view taken along the line VI-VI of the assembly represented in FIG. 5;

FIGS. 7A to 7C show different variants of sealing means interposed between the two half-covers of the intermediate part of the nacelle, and

- Figures 8A and 8B show two variants of stiffening brackets interposed between the axes of said half-covers.

In all of these figures, identical or similar references designate members or sets of identical or similar members. The expressions "superior" or "upper part of nacelle" refer to the position occupied by the nacelle when it is suspended under an aircraft wing, and designate areas nearest the edges of the drawing boards annexed hereto.

Concerning the movable elements, and in particular the two half-covers, the elements are represented in solid lines when they are in the closed position, and in dotted lines when they are in the open position.

We therefore place ourselves in the particular case of a propulsion unit of new generation, as shown in Figure 3, suspended from an aircraft wing 13 via a mast 15 cooperating with the downstream portion 1 1 of the nacelle 1.

As has been indicated previously, in this particular configuration, it is no longer possible to envisage an articulation of the two half-movable covers 17a and 17b on the mast 15, or in any case, more solely on this mast.

According to a first embodiment shown in FIG. 4, for each half-cover 1 7a, 1 7b, a fitting 21 is fixed on the one hand on the upper part of the inner downstream partition 23 of the air inlet, and on the other hand a corresponding fitting 25 upstream of the inner face of the corresponding movable half cover 17a, 17b.

A pin 27 secured to one of these brackets and freely traversing the other fitting, allows to realize is a pivoting articulation of the dem i-movable cover 1 7a, 17b relative to the inner partition 23. This piece is stopped in translation by any means known to those skilled in the art once in place.

Structural and through fixing can be envisaged by providing access in the closed upstream receiving structure (air intake) or downstream (inverter) either in the internal partitions of the structures, or on the outer cowlings.

To bring here a simple precision, the internal partition 23, quite conventional in the structure of the nacelle, is a sheet metal wall of substantially an anew form, fixed on the one hand on the upstream edge of the fan casing 19, and secondly on the inner downstream face of the outer skin of the air inlet 5.

Although it has not been shown in the accompanying figures articu tion means similar to those that have just been described are also provided between the upper edge downstream of each half cover 17a, 17b and the upper upstream edge of the downstream part of nacelle 1 1, that is to say in zone Z2 shown in FIG.

In this configuration, the pivot located downstream can be supported either by the fixed upstream structure of the inverter, or by the upstream structure of the fixed structure downstream of the nacelle (case of nacelle without inverter).

As can be understood, these extremely simple design articulating means make it possible to mount the two fan half-covers 17a, 17b pivoting on the fixed structure of the nacelle 1, without any cooperation with the mast 15.

Note of course that in the event that the mast 15 extends in part in the intermediate zone 7 of the nacelle 1, it could be envisaged that each half-fan cowl 17a, 17b is mounted hinged in part upstream on the rear wall 23, and partly downstream on the mast 15.

Referring now to Figures 5 and 6, which shows another embodiment of the invention.

As can be seen in these figures, this time the upstream portion of each half-fan cover 1 7a, 17b is pivotally mounted via a hinge having a shape swan neck 29a , 29b, not on the rear wall 23, but on a support 31, integral with the fan casing 19.

The axes of rotation of these chains are respectively indicated by references 33a and 33b.

As can be seen in FIG. 6, the support 31 may have a substantially T-shaped section.

This support 31 may extend over the entire length of the nacelle intermediate portion 7.

In a variant, it is possible to envisage several supports spaced apart from one another, and in particular, a support at each upstream and downstream end of the two half-blower covers 17a, 17b.

Note that the or supports 31 may be reported by riveting or welding on the fan casing 1 9, or formed (s) in one piece with at least a portion of the fan casing.

Similarly it is conceivable to achieve a mixed pivot assembly such as an upstream structure carried by the engine casing and a downstream pivot structure carried by the nacelle or the mast. The reciprocal is also permitted, that is, the downstream pivot structure may be carried by the housing of the engine and the upstream pivot structure carried by the downstream structure of the air inlet.

Referring now to FIGS. 7A to 7C, there are shown various means for sealing between the upper edges of the two half-blower covers 17a, 17b.

According to a first variant shown in FIG. 7A, a longitudinal duct 35 is attached to one of these two half-covers, this chute being adapted to come into sealing contact (with the use of a seal 37) with the inner face of the other 17b half-blower cover.

Note that this chute 35 must have a particular section as shown in Figure 7A, so as to allow the independent opening of the two half-blower covers 17a and 17b.

More specifically, this shape allows the pivoting of the fan half-casing 17b around the axis of rotation 33b, the other half of the fan cowl 17a remaining in the closed position.

In the variant shown in Figure 7B, there are comma-section seals 39a, 39b along the two upper edges of the two half-blower covers 17a, 17b.

These joi nts are preferably of the type bu ll es, that is to say having a hollow portion, facilitating their mutual deformation when they come into contact with one another, which improves the seal.

In the variant shown in Figure 7C, the seals 41a, 41b are arranged on brackets 43, 43b respectively fixed on the inner faces of the two half-covers 17a, 17b.

Thanks to this particular disposition, it is avoided to print an overpressure at these joints when opening each half-fan cover 17a, 17b.

Referring now to Figures 8A and 8B, on which there is shown means for strengthening the stiffness of the articulation of the two half-blower covers 17a and 17b.

In the variant shown in FIG. 8A, which is compatible with the sealing means of FIGS. 7B or 7C, it can be seen that one or more of the ferrous elements 45 can be disposed between each other, which have physical axes 47a, 47b of each other. hinges of the two half-blower covers 17a, 17b. These physical axes 47a, 47b, concentric with the axes of rotation 33a, 33b, may for example extend between the fixed upstream fittings 21 and downstream in the first embodiment mentioned above, or between the T-shaped supports 31 in the second embodiment described above.

In the particular case of FIG. 8A, each fitting 45 may have a horseshoe shape, notably allowing the upper edges of the two half-blower covers 17a, 17b to be deflected, as well as their associated angles 43, 43b. , when retaining the sealing variant shown in Figure 7C.

In the variant shown in Figure 8b, it can be seen that the fitting can be flush with the outer faces of the two half-blower covers 17a, 17b, when the latter is in the closed position.

This fitting variant assumes an articulation of the two half-blower covers 17a; 17b with goose-neck hinges, similar to those shown in FIG.

As can be understood from the foregoing description, the present invention makes it possible to articulate the two half-blower covers 17a, 17b without resorting to the suspension pole 15.

This par ticularly is com plex with the new generation propulsion systems.

Note of course that, in the event that the suspension mast 15 encroach at least in part on the intermediate areas 7 of the nacelle, it would be entirely possible to combine the teachings of the present invention with a hinge at least partial of each half fan cowl 17a, 17b, on the upstream portion of the suspension mast 15.

Of course, the present invention is not limited to the modes of real isation described and shown, fou rn is as sim ple examples.

Claims

1. A propulsion unit for an aircraft, comprising a nacelle (1) and a turbojet, said nacelle comprising an intermediate part (7) and said turbojet engine comprising a fan casing (19) situated inside said intermediate part (7), said part intermediate member (7) comprising two half-fan case covers (17a, 17b) each movable about substantially longitudinal axes (33a, 33b) located in the upper part of said nacelle, between a closed position in which they cover said housing (19) and an open position in which they allow access to the periphery of this housing (19), said half-covers (17a, 17b) being articulated on fixed elements selected from the group comprising:

at least one internal partition (23) of said nacelle, and

- Support means formed integrally with said fan casing.

2. Propulsion unit according to claim 1, wherein the hinge means of said half-covers (17a, 17b) comprise fittings (21, 25) secured respectively to said partition (23) and said covers (17a, 17b), and pins (27) cooperating with these fittings (21, 25) allowing their rotary movements relative to each other.

The propulsion assembly of claim 1, wherein said support means comprises a single support leg extending the full length of said half-covers (17a, 17b).

4. Propulsion unit according to claim 1, wherein said support means comprise a plurality of support legs, separated from each other along the length of said half-covers (17a, 17b).

5. Propulsion unit according to any one of the preceding claims, wherein sealing means (35, 37; 39a, 39b; 41a, 41b) are interposed between the two contiguous edges of the two half-covers (17a, 17b), these means being selected from the group consisting of seals and a sealing trough.

6. Propulsion unit according to claim 5, wherein said seals (41a, 41b) are fixed on brackets (43a, 43b) disposed on the inner faces of said half-covers (17a, 17b).