FR3077847A1 - THRUST INVERTER WITH SHUTTERS FOR AN AIRCRAFT PROPULSIVE ASSEMBLY - Google Patents

Abstract

The invention relates to a flap thrust reverser 6 for an aircraft propulsion unit in which the flaps 6 are deployed or retracted by inflation or deflation of bladders 61.

Description

Flap thrust reverser for aircraft propulsion system

The present invention relates to the field of aircraft propulsion systems of the type comprising a nacelle, a turbofan engine and a thrust reverser. The invention relates more specifically to a shutter thrust reverser.

A shutter thrust reverser allows all or part of the cold air flow circulating in the nacelle's secondary vein to be redirected towards the front so as to create a counter-thrust contributing to the braking of the aircraft .

Such a thrust reverser is movable between a position in direct jet and a position in reverse jet. In direct jet, the flaps are retracted so as to allow the circulation of the cold air flow in the secondary stream, this air flow thus contributing to the thrust of the aircraft. In reverse jet, the flaps are deployed so as to at least partially close the secondary vein, thereby deflecting at least part of the cold air flow towards a radial opening of the nacelle. The radial opening is typically equipped with grids of blades arranged to direct the air flow thus deflected towards the front of the aircraft.

In the inverters of the prior art, the movement of the flaps from one position to another is ensured by a mechanism of connecting rods connected to the flaps.

According to a first known technique, each flap is connected on the one hand to the sliding cover (“transcowl” in English) and on the other hand to a connecting rod itself connected to the internal fixed structure of the reverser. The translation of the sliding cover thus displaces the flaps from one position to the other via the connecting rods.

However, when the reverser is in direct jet, the connecting rods extend through the secondary vein and consequently introduce aerodynamic disturbances, which reduces the efficiency of the propulsion unit in direct jet.

A second known technique consists in housing the connecting rods in the sliding hood in direct jet as described in document US 2012/0187214 A1.

The housing of the connecting rods in the sliding cover requires a larger sliding cover and therefore a relative increase in the dimensions of the nacelle, which also reduces the efficiency of the direct jet propulsion unit.

In addition, the rod reverser mechanisms are complex and costly in terms of assembly and maintenance.

An object of the present invention is to overcome the aforementioned drawbacks by proposing a thrust reverser improving the efficiency of the propulsion unit in direct jet.

To this end, the invention relates to a thrust reverser for an aircraft propulsion unit, comprising an internal fixed structure, a sliding cover, an evacuation structure and shutter flaps. The internal fixed structure and the sliding cover delimit a vein, also called secondary vein in the present document, capable of channeling an air flow in a longitudinal direction when the thrust reverser is in a position in direct jet.

The shutters are retracted when the thrust reverser is in the direct jet position.

The shutters are movable between the position in direct jet and a position in reverse jet in which they are deployed in the vein so as to deflect at least part of the air flow in the direction of the exhaust structure.

The thrust reverser according to the invention comprises inflatable bladders which cooperate with the shutter flaps. The bladders are deflated when the thrust reverser is in the direct jet position so as to retract the shutter flaps. The bladders are inflated when the thrust reverser is in the reverse jet position so as to keep the shutter flaps deployed in the vein.

Such a thrust reverser does not require any connecting rod to move the flaps from one position to another and thus limits aerodynamic disturbances in direct jet while simplifying the mechanism of the reverser, in particular by reducing the number of parts.

The invention also makes it possible to reduce the overall mass of the propulsion unit.

Preferably, the evacuation structure can comprise grids of blades in order to allow or improve the redirection towards the front of the aircraft of the air flow deflected by the flaps.

In one embodiment, the thrust reverser may comprise a device for conveying an inflation fluid capable of conveying the inflation fluid from a source of inflation fluid to the interior of the bladders.

The source of inflation fluid can be a volume inside or outside the nacelle.

Preferably, the inflation fluid can be compressed air.

In particular when the inflation fluid is compressed air, the source of inflation fluid may include an inflation fluid reservoir. Preferably in this case, the conveying device can be arranged to take the inflation fluid from this reservoir.

In this embodiment, the filling of the reservoir can be done by a pump, for example electric, capturing air outside the nacelle or in the secondary vein. This tank can be pressurized by capturing air in the reactor compressor.

Furthermore, the reverser may include one or more chemical generators of inflation fluid. This or these chemical generators can be pyrotechnic.

The chemical generator (s) can be located in one or more bladders, or in said inflation fluid reservoir, or in any other place at the level of said inflation source.

In one embodiment, the thrust reverser may include an inflation device capable of regulating an inflation pressure of the bladders. This inflation device may comprise or consist of a valve for regulating the inflation pressure.

Preferably, this inflation device can be arranged to define an inflation pressure equal to or less than an ambient pressure when the thrust reverser is in the direct jet position and an inflation pressure greater than this ambient pressure when the reverser thrust is in the reverse jet position.

The ambient pressure can be measured in the secondary vein of the nacelle or outside the nacelle.

When the inflation device defines an inflation pressure equal to or less than the ambient pressure (direct jet), this device is preferably arranged to press and stabilize the obturation flaps so as to define a smooth secondary vein.

The thrust reverser can also include a so-called mobile part, this being mobile between:

a first position when the thrust reverser is in the direct jet position, and

- a second position when the thrust reverser is in the reverse jet position.

Between this first and this second position, the reverser is "in transit".

The inflation device can cooperate with this mobile part so as to define an inflation pressure equal to or less than the ambient pressure when the mobile part is in the first position and an inflation pressure greater than the ambient pressure when the mobile part is in the second position.

Preferably, the movable part can be the sliding cover.

Alternatively, the mobile part can be another part of the thrust reverser, the mobility of which is preferably synchronized with the movement of the sliding cover.

In one embodiment, the inflation pressure can be defined or modulated as a function of the position of the movable part, for example so as to coordinate the opening of the sliding cover with the deployment of the shutters. This can make it possible to optimally adjust the cross section of the motor flow during the transit phase.

In one embodiment, the thrust reverser may comprise a deflation device capable of extracting inflation fluid from the bladders when the thrust reverser passes from the position in reverse jet to the position in direct jet. This deflation device may include a vent valve (external or downstream of the door in the vein), possibly supplemented by a suction device (for example a vacuum ejector).

The extraction can be carried out over all or part of the duration of the reversing of the inverter, for example at the end of the folding stroke.

Preferably, the thrust reverser can comprise at least one bladder inflation pressure sensor arranged to control, as a function of the bladder inflation pressure, the inflation device and / or the deflation device.

Another advantage of the thrust reverser according to the invention is that it can allow the flaps to be quickly retracted, especially in the event of an aborted landing. Indeed, the pressure of the cold air flow circulating in the secondary vein tends to favor the deflation of the bladders and therefore the retraction of the flaps.

Thus, such a thrust reverser can make it possible to accelerate the reclosing of the sliding hood in the event of an aborted landing, that is to say the passage of the sliding hood from an open position in reverse jet to a position closed in direct jet. . For example, it is possible to provide for the retraction of the flaps before total closure of the sliding cover. In fact, when the flaps are still partially deployed in the secondary stream, the air flow circulating in the nacelle exerts on these flaps a force which tends to oppose the closing of the sliding cover. Correlatively, the venting or vacuuming of the bladders and the premature retraction of the flaps which results therefrom eliminates such a force and makes it possible to accelerate the last phase of reclosing of the sliding cover.

The invention also relates to an aircraft propulsion unit comprising such a thrust reverser.

Other characteristics and advantages of the invention will appear on reading the non-limiting description which follows and the appended figures, in which:

FIG. 1 is a schematic perspective view of a propulsion unit with thrust reverser with blades of blades, in the direct jet position;

Figure 2 is a schematic perspective view of the propulsion unit of Figure 1 in which the reverser is in reverse jet position;

Figure 3 is a schematic perspective view of a propulsion unit with thrust reverser in the direct jet position;

Figure 4 is a partial schematic view of a thrust reverser according to the invention, in the direct jet position;

Figure 5 is a partial schematic view of the thrust reverser of Figure 4, in an intermediate position;

Figure 6 is a partial schematic view of the thrust reverser of Figure 4, in reverse jet position;

Figure 7 is a schematic perspective view of a flap and a thrust reverser bladder according to the invention;

FIG. 8 is a partial schematic view of a thrust reverser according to the invention, in the direct jet position;

Figure 9 is a partial schematic view of the thrust reverser of Figure 8, in reverse jet position.

Identical or similar elements are identified by identical reference signs in all of the figures.

An aircraft propulsion assembly 1 is illustrated in FIG. 1. This propulsion assembly 1 comprises a nacelle, a reactor mast 2 and a turbofan engine type engine (not shown) housed in the nacelle. The engine mast 2, partially shown, is intended to be fixed to a wing (not shown) or to the fuselage (not shown) of the aircraft.

The nacelle comprises an air inlet 11 adapted to allow optimum capture towards the turbojet of the air necessary for the supply of a fan 3 and of internal compressors (not shown) of the turbojet.

The propulsion unit 1 extends in a longitudinal direction DI shown coincident with the axis of the engine.

Figures 1 and 2 illustrate the propulsion unit 1 with a thrust reverser in the "direct jet" position and in the "reverse jet" position respectively.

The thrust reverser comprises a discharge structure 41 and a sliding cover 42.

In this example, the discharge structure 41 comprises grids of blades.

The sliding cover 42 is movable in translation between the direct jet position and the reverse jet position.

The translation of the sliding cover 42 is typically carried out by sliding this cover 42 along rails (not shown) integral with the mast 2 and arranged on either side thereof.

FIG. 3 shows an aircraft propulsion unit 1 similar to that of FIG. 1 from a perspective showing an exhaust nozzle 5 downstream of the turbojet engine. The exhaust nozzle 5 comprises a gas ejection cone 51 ("plug" in English) and a primary nozzle 52 ("nozzle" in English). The ejection cone 51 and the primary nozzle 52 of the exhaust nozzle 5 define a passage for a flow of hot air leaving the turbojet engine.

The primary nozzle 52 is integral with a fixed structure 43 of the thrust reverser. The part of the fixed structure 43 shown in FIG. 3 is also called the internal fixed structure.

The internal fixed structure 43 and the sliding cover 42 of the thrust reverser delimit a vein capable of channeling an air flow in the longitudinal direction DI when the thrust reverser is in the direct jet position illustrated in FIGS. 1 and 3.

The air flow circulating in this vein, also called secondary vein, is a cold air flow from the turbojet engine.

With reference to FIG. 2, the position in reverse jet of the thrust reverser allows a radial evacuation of the cold air flow through the evacuation structure 41.

In order to deflect at least part of this air flow towards the exhaust structure 41 when the thrust reverser is in the reverse jet position, the thrust reverser comprises shutter flaps 6 (see Figures 4 to 6, 8 and 9).

Figures 4 to 6 schematically illustrate a thrust reverser according to the invention respectively in the direct jet position, in an intermediate position and in the reverse jet position. A single shutter 6 is shown in these figures. Of course, the reverser comprises several adjacent flaps 6 in order to preferably close off the entire secondary stream in reverse jet. Each shutter 6 can operate according to the principle illustrated in FIGS. 4 to 6.

These Figures 4 to 6 and Figures 8 and 9 also show a front frame 71 of an intermediate section 7 of the nacelle, also visible in Figure 3. From one position of the inverter to the other, one can in particular note that the fixed internal structure 43 as well as the vane grids 41 are in this example fixed relative to the front frame 71. On the contrary, the sliding cover 42 is movable relative to these various elements. Thus, in the direct jet position (FIG. 4), the sliding cover 42 is advanced towards the front frame 71 and covers the grids of blades 41: the sliding cover 42 is in the closed position. When the reverser changes from the direct jet position to the reverse jet position (Figures 5, 6 and 9), the sliding cover 42 moves back with respect to the front frame 71 so as to uncover the grids of the blades 41: the cover sliding 42 is then in the open position.

In an embodiment not shown, the vane grids 41 can be movable relative to the front frame 71, in which case the grids 41 are housed in a casing of the front frame 71 in direct jet.

Still with reference to FIGS. 4 to 6, the shutter flaps 6 are movable between the position in direct jet and the position in reverse jet.

When the thrust reverser is in the direct jet position (FIG. 4), the shutter flaps 6 are retracted so as to allow the circulation of the cold air flow F1 in the secondary stream. The air flow F1 thus contributes to the thrust of the aircraft. A retracted flap forms, with an inner surface of the sliding cover 42, a common surface of the secondary stream as smooth as possible so as to limit aerodynamic disturbances.

When the thrust reverser is in the reverse jet position (FIG. 6), the shutter flaps 6 are deployed in the vein so as to deflect at least part of the air flow F1 towards the structure of evacuation 41.

As shown in FIGS. 4 to 6, the thrust reverser comprises inflatable bladders 61 which cooperate with the shutter flaps 6.

When the thrust reverser is in the direct jet position (FIG. 4), the bladders 61 are deflated so as to retract the shutter flaps 6. The bladders 61 can advantageously be put at a pressure lower than that of the vein by venting to the outside, or even under vacuum with respect to ambient pressure by the use of a suction device, for example a vacuum ejector. This allows the shutters 6 to be pressed firmly against the external part of the secondary vein and to stabilize them as much as possible in this position.

When the thrust reverser is in the reverse jet position (FIG. 6), the bladders 61 are inflated so as to keep the shutter flaps 6 deployed in the vein.

Figure 7 shows a shutter 6 and a corresponding bladder 61 inflated.

In other words, the deployment or retraction of the flaps 6 is controlled by the inflation or deflation of the bladders 61, and therefore depends in particular on the pressure of the fluid within the bladders 61.

The bladders 61 are arranged to be inflated with an inflation fluid which is preferably compressed air. Indeed, several types of compressed air sources are accessible or can be easily fitted into a propulsion unit 1.

To convey the compressed air from a source of compressed air to the interior of the bladders 61, the thrust reverser comprises a device for conveying compressed air (not shown). This device typically includes pipes and means for connection to fluid withdrawal and distribution devices.

According to a variant, the reverser comprises a reservoir (not shown) of compressed air from which the compressed air taken to the bladders 61 is taken. In another variant, the compressed air is taken directly from the engine.

In the example of FIGS. 4 to 6, the reverser comprises an inflation device 62, of the regulating valve type, and a deflation device 63, of the vacuum ejector type.

The inflation device 62 makes it possible to regulate an inflation pressure of the bladders 61.

For example, the inflation device 62 can be arranged to define an inflation pressure equal to or less than an ambient pressure, measured in the secondary vein or outside the nacelle, when the thrust reverser is in the position in direct jet (Figure 6) and an inflation pressure higher than this ambient pressure when the thrust reverser is in the reverse jet position (Figure 6) or in an intermediate position when the flaps 6 are deployed (Figure 5).

The inflation pressure in reverse jet must be able on the one hand to inflate the bladders 61 in order to deploy the flaps 6 in the secondary vein and, on the other hand, capable of maintaining the flaps 6 thus deployed to divert the flow of air F1 towards the exhaust structure 41.

In this example, the inflation device 62 cooperates with the sliding cover 42 so as to define an inflation pressure as a function of the position of this cover 42. When the sliding cover 42 is in the closed position (FIG. 4), the device inflation 62 defines an inflation pressure equal to or less than the ambient pressure. When the sliding cover 42 is in the open position (FIG. 5 or 6), the inflation device 62 defines an inflation pressure greater than the ambient pressure.

The deflation device 63 makes it possible to extract the compressed air contained in the bladders 61 when the thrust reverser passes from the position in reverse jet (FIG. 6) to the position in direct jet (FIG. 4).

The thrust reverser according to the invention preferably comprises a sensor 64 for bladder inflation pressure 61.

Such a sensor 64 makes it possible in particular to control the inflation device 62, and possibly the deflation device 63, as a function of the effective inflation pressure of the bladders 61. This device makes it possible to regulate the pressure in the bladders in all the operating phases of the reverser to ensure optimal pressurization of the bladders under all operating conditions.

Figures 8 and 9 show a thrust reverser according to the invention in direct jet (Figure 8) and reverse jet (Figure 9). This thrust reverser is similar and operates on the same principle as the reverser in Figures 4 to 6.

Of course, the invention is not limited to the examples which have just been described and numerous modifications can be made to these examples without departing from the scope of the invention. For example, the thrust reverser may include a mechanical return device (not shown) to accelerate deflation of the bladders 61. This return device may include one or more cables cooperating with the flaps 6 so as to exert on the flaps 6 an effort to retract them. For another example, the flaps 6 can be acoustically treated.

Claims (12)

1. Thrust reverser for an aircraft propulsion unit, comprising an internal fixed structure (43), a sliding cover (42), an evacuation structure (41) and shutter flaps (6), the internal fixed structure (43) and the sliding cover (42) delimiting a vein capable of channeling an air flow (Fl) in a longitudinal direction (Dl) when the thrust reverser is in a position in direct jet, the shutters (6) being retracted when the thrust reverser is in the direct jet position, the shutter flaps (6) being movable between the direct jet position and a reverse jet position in which they are deployed in the vein of so as to deflect at least part of the air flow (Fl) in the direction of the exhaust structure (41), characterized in that it comprises inflatable bladders (61) which cooperate with the shutter flaps (6 ), the bladders (61) being deflated when the thrust reverser is in the posi tion in direct jet so as to retract the shutter flaps (6), the bladders (61) being inflated when the thrust reverser is in the reverse jet position so as to keep the shutter flaps (6) deployed in the vein. 2. A thrust reverser according to claim 1, comprising a device for conveying an inflation fluid capable of conveying the inflation fluid from a source of inflation fluid to the interior of the bladders (61). 3. A thrust reverser according to claim 2, in which the inflation fluid is compressed air. 4. A thrust reverser according to claim 2 or 3, the source of inflation fluid comprising an inflation fluid reservoir, the conveying device being arranged to draw the inflation fluid from this reservoir. 5. Thrust reverser according to any one of claims 1 to 4, comprising a chemical generator of inflation fluid. 6. A thrust reverser according to any one of claims 1 to 5, comprising an inflation device (62) capable of regulating an inflation pressure of the bladders (61), this inflation device (62) being arranged to define a pressure inflation pressure equal to or less than an ambient pressure when the thrust reverser is in the direct jet position and an inflation pressure greater than this ambient pressure when the thrust reverser is in the reverse jet position. 7. Thrust reverser according to claim 6, comprising a movable part (42) between a first position when the thrust reverser is in the direct jet position and a second position when the thrust reverser is in the jet position reverse, the inflation device (62) cooperating with the mobile part (42) so as to define an inflation pressure equal to or less than the ambient pressure when the mobile part (42) is in the first position and a higher inflation pressure at this ambient pressure when the movable part (42) is in the second position. 8. A thrust reverser according to claim 7, in which the movable part (42) is the sliding cover. 9. Thrust reverser according to any one of claims 6 to 8, comprising a sensor (64) for bladder inflation pressure (61) arranged to control the inflation device (62) as a function of the bladder inflation pressure (61). 10. Thrust reverser according to any one of claims 1 to 9, comprising a deflation device (63) capable of extracting inflation fluid from the bladders (61) when the thrust reverser passes from the position in reverse jet to the position in direct jet. 11. A thrust reverser according to claim 10, comprising a bladder inflation pressure sensor arranged to control the deflation device (63) as a function of a bladder inflation pressure (61). 12. Propulsion unit (1) of an aircraft, characterized in that it comprises a thrust reverser according to any one of claims 1 to 11. 1/5