Reverse thrust device for aircraft bypass turbojet nacelle

Abstract

A thrust reverser (30) for bypassing a turbojet engine nacelle in an aircraft, the thrust reverser having a generally annular shape around an axis and including an annular frame (34) for securing a deflection cascade (38), the frame (34) including: - a first truncated conical wall (52) widening in a downstream direction and including an upstream peripheral edge (52a) and a downstream peripheral edge (52b), the upstream peripheral edge being configured to attach to the casing of the turbojet engine, the downstream peripheral edge extending in a continuation of the wall and for securing the upstream end (38a) of the cascade (38); and - a second annular wall (54) extending radially outward from the outer truncated conical surface (52c) of the first wall (52), the first wall and the second wall (52, 54) being integrally formed, and the second wall (54) including an axial orifice (64) through which an actuator (44) passes.

Description

Technical Field

[0001] This invention relates to the field of bypass turbojet engine nacelles for aircraft, and particularly to thrust reversers mounted on such nacelles. Background Technology

[0002] The prior art includes document US 4,998,409 A.

[0003] Thrust reversers are now widely used in aircraft nacelles, particularly those housing bypass turbojet engines. In a known manner, such turbojet engines generate a hot airflow (called the main flow) from the combustion chamber via rotating fan blades, and a cool airflow (called the secondary flow) that flows outside the turbojet engine through an annular channel formed between the turbojet engine's shield and the nacelle's inner wall. These two airflows are then expelled from the turbojet engine through the rear of the nacelle, thus generating thrust.

[0004] In this configuration, the role of the thrust reverser is to enhance the aircraft's ground braking capability during the landing phase by redirecting at least a portion of the thrust generated by the turbojet engine forward. Specifically, when the thrust reverser is operational, it obstructs annular channels of cold airflow (i.e., secondary airflow) and directs that airflow toward the front of the cabin, thereby generating reverse thrust.

[0005] The device used to redirect the cold airflow varies depending on the type of thrust reverser. However, in all cases, the thrust reverser is constructed with a movable fairing that can move between an deployed position (also known as the reverse thrust position) and a retracted position (also known as the direct injection position). In the deployed position, the fairing opens a channel for the deflected airflow within the nacelle; in the retracted position, it closes this channel. In this way, the fairing can activate other deflecting devices, such as wings. In this case, the wings, activated by the movement of the movable fairing, at least partially obstruct the passageway through which the secondary airflow flows.

[0006] In addition, in the case of a thrust reverser with deflector blades, the deflector blades redirect the airflow.

[0007] Figure 1 and Figure 2 The diagram illustrates a prior art thrust reverser. This thrust reverser is either a cascade thrust reverser type or a cascade-type thrust reverser.

[0008] This type of thrust reverser includes at least one movable fairing 9 movable relative to a fixed portion including an upstream annular frame 15, the fairing 9 having an outer wall 17 and an inner wall 10, the inner wall being designed for direct injection of the turbojet engine ( Figure 1 The outer wall of the annular channel 6 is defined, and the secondary flow F11 flows in the annular channel. The thrust reverser also includes at least one wing 11, which is hinged to the movable fairing 9, and is actuated by at least one link 12 when the movable fairing moves downstream, such that in the thrust reverse position ( Figure 2 Each wing 11 includes an extension into the annular channel 6 to deflect at least a portion of the secondary flow F11 to a region outside the annular channel 6.

[0009] In the case of this type of thrust reverser, the reorientation of the secondary flow F11 is achieved by deflecting the blades 13. The movable fairing 9 has only a simple sliding function designed to expose or cover these blades 13. The translation of the movable fairing 9 is achieved along a longitudinal axis that is substantially parallel to the axis of the nacelle 1 and the thrust reverser.

[0010] like Figure 1 As shown, the receiving portion 14 is provided in the fairing 10 to accommodate the blade array 13 when the thrust reverser is not activated (i.e., in the direct injection position).

[0011] The gratings 13 are arranged adjacent to each other in the annular region surrounding the annular channel 6, and the blade gratings 13 are arranged side-to-side such that there are no gaps between these blade gratings. In this way, the entire secondary flow F11 deflected by the wing 10 passes through the blade gratings 13. A device (not shown) for moving and guiding the movable fairing 9 is located below the blade gratings 13.

[0012] An annular deflection shield 19, commonly referred to as the deflection edge, covers the inner periphery of the frame 15. The shield 19 has a circular cross-sectional shape and extends from the outer periphery of the annular channel 6 to the upstream end of the blade cascade 13.

[0013] For efficiency reasons, the shroud 19 must have a large radius of curvature. Furthermore, in order to maximize the length of the blade cascade 13 and deflect the secondary flow F11 upstream as much as possible, it is necessary to arrange the blade cascade 13 as close as possible to the outer wall 17 of the fairing 9. The limited length of the fairing's housing and the large radius of the shroud 19 reduce the length of the blade cascade 13.

[0014] To overcome this drawback, it is known to arrange the blade cascade 13 at an angle. Thus, the blade cascade extends as a whole around the annular channel 6 in a truncated cone manner.

[0015] Document EP-A1-1 229 237 describes such a thrust reverser in which the blade cascades are arranged at an angle. However, in this case, it is no longer possible to arrange a device for moving and guiding the movable fairing below the blade cascades. The blade cascades are then spaced apart from each other, such that the aforementioned moving and guiding device is arranged between two adjacent blade cascades.

[0016] In this situation, a portion of the secondary flow may escape into the gap between the blades, which has the effect of reducing the deflection of the secondary flow and thus reducing the efficiency of the thrust reverser.

[0017] Furthermore, the frame 15 of the thrust reverser is a multifunctional structural component that can be complex and expensive to manufacture. The frame 15 is fixed to and holds the blade cascade 13 at its upstream end. The frame 15 holds the shroud 19, which limits interference with the airflow through the blade cascade 13. Finally, the frame 15 can be used to support the moving parts (not shown) of the fairing 9, and therefore must withstand relatively high forces.

[0018] The frame 15 of the thrust reverser is typically assembled from multiple components (especially multiple plates).

[0019] Figure 3 and Figure 4 Another prior art thrust reverser is shown, and the position of one of the devices that move the fairing 9 between its two aforementioned positions is shown, these moving devices being in the form of actuator 20.

[0020] The actuator 20 has an elongated shape and extends parallel to the longitudinal axis of the nacelle and the thrust reverser. The actuator has an upstream end 20a fixed to a fixed portion including the frame 15 and a downstream end 20b fixed to the fairing 9.

[0021] As in Figure 4 As can be seen more clearly, the frame 15 is assembled from multiple components 15a, 15b, 15c, 15d, etc., and a large opening 21 is formed axially through the frame 15 to allow the actuator 20 to be mounted. This opening 21 extends on the multiple components and in the connection areas of the multiple components, which weakens the frame 15 and may require the frame to be oversized (in particular, to extend the frame along the axis or thicken it in the radial direction) to ensure that the blade cascade 13 is held in place.

[0022] In particular, the present invention proposes an improvement over the prior art that simplifies the design of the thrust reverser frame, and especially simplifies the manufacture of the thrust reverser frame. Summary of the Invention

[0023] This invention proposes a thrust reverser for the nacelle of an aircraft bypass turbojet engine, the thrust reverser having a generally annular shape about an axis and comprising:

[0024] - A fixed upstream portion, said fixed upstream portion comprising a ring frame.

[0025] -Downstream annular support component,

[0026] - A deflection vane cascade, the upstream end of which is fixed to the frame, and the downstream end of which is fixed to the support member.

[0027] - A fairing, movable from an upstream position to a thrust-reversing downstream position, wherein the fairing covers the blade cascades in the upstream position and the blade cascades are uncovered in the thrust-reversing downstream position.

[0028] - A deflecting element for deflecting the secondary flow of a turbojet engine through the blade cascade when the cowling is in a downstream position of the cowling, and

[0029] - An actuator with an elongated shape, the upstream end of which is fixed to a fixed portion, and the downstream end of which is fixed to the fairing.

[0030] The frame is characterized in that it comprises:

[0031] - A first truncated conical wall, the first truncated conical wall widening in a downstream direction and including an upstream peripheral edge and a downstream peripheral edge, the upstream peripheral edge being configured to be fixed to the casing of a turbojet engine, the downstream peripheral edge extending in a continuation of the wall and used to fix the upstream end of the blade cascade, and

[0032] - A second annular wall, the second annular wall extending radially outward from the outer truncated conical surface of the first wall.

[0033] The first wall and the second wall are integrally formed, and the second wall includes an axial orifice through which the actuator passes.

[0034] The advantage of this invention is that the frame of the thrust reverser is formed as a single piece, and therefore is integral. This simplifies the design and manufacture of the frame, preferably by machining a block of material, for example, in the form of a plate. Furthermore, the actuator passes through an opening formed only in one wall of the frame, which simplifies assembly and has almost no impact on the mechanical strength of the frame. Additionally, the first wall of the frame has a truncated conical shape, and the downstream edge of this first wall is configured to be directly fixed to the upstream end of the blade cascades, which is particularly advantageous when these blade cascades are inclined relative to the axis of the thrust reverser and extend substantially within the continuation of this wall.

[0035] The thrust reverser according to the invention may include one or more of the following features, which are employed in isolation or in combination with each other:

[0036] - The actuator extends parallel to the axis;

[0037] - Each blade in the blade cascade extends in a plane inclined at an angle between 5° and 20° relative to the axis; and

[0038] - Each actuator extends between two adjacent cascades and traverses the plane of those cascades;

[0039] -The downstream end of the actuator is surrounded by the support members in a way that they are far apart from each other;

[0040] - The second wall includes an upstream surface having a first recess and a downstream surface having a second recess, the orifice being formed at the bottom of the first recess;

[0041] - At least two partitions, parallel to each other and parallel to the axis, extend into each of the first recesses in the first recesses, these partitions being connected to the bottom of the recesses and arranged on both sides of the orifice;

[0042] - The actuator is fixed to the partition;

[0043] - The second recess is formed by a plurality of cavities defined by a first annular web and a second radial web;

[0044] - The frame includes a third annular wall extending radially inward from the inner truncated conical surface of the first wall, and reinforcing ribs extending radially between the inner truncated conical surface and the downstream annular surface of the third wall;

[0045] - The annular deflector shield is supported and fixed on the inner circumference of the third wall and the downstream end of the inner truncated conical surface.

[0046] The present invention also relates to a bypass turbojet engine for an aircraft, including the thrust reverser as described above. Attached Figure Description

[0047] The invention will be better understood through the following description of non-limiting examples and with reference to the accompanying drawings, and other details, features, advantages and characteristics of the invention will become clearer in the drawings:

[0048] - Figure 1 This is a partial schematic diagram of the longitudinal section of a thrust reverser device according to existing technology, located in the direct injection position;

[0049] - Figure 2It is in the reverse thrust position. Figure 1 A partial schematic diagram of the longitudinal section of the thrust reverser;

[0050] - Figure 3 This is a partial schematic diagram of the longitudinal section of another thrust reverser device according to the prior art, located in the reverse thrust position;

[0051] - Figure 4 yes Figure 3 An enlarged view of a portion of the thrust reverser;

[0052] - Figure 5 This is a partial schematic diagram of the longitudinal section of a thrust reverser device according to an embodiment of the present invention, located in the direct injection position;

[0053] - Figure 6 It is in the reverse thrust position. Figure 5 A partial schematic diagram of the longitudinal section of the thrust reverser;

[0054] - Figure 7 yes Figure 5 An enlarged view of a portion of the thrust reverser;

[0055] - Figure 8 yes Figure 5 A partial schematic diagram of the longitudinal section of the frame of the thrust reverser device;

[0056] - Figure 9 This is observed from the downstream. Figure 5 A partial schematic perspective view of the thrust reverser device;

[0057] - Figure 10 It was observed from upstream. Figure 5 A partial schematic perspective view of the thrust reverser device;

[0058] - Figure 11 It was observed from upstream. Figure 5 A partial schematic perspective view of the frame of the thrust reverser; and

[0059] - Figure 12 This is observed from the downstream. Figure 5 A partial schematic perspective view of the frame of the thrust reverser device. Detailed Implementation

[0060] Now for reference Figures 5 to 12 , Figures 5 to 12 A preferred embodiment of the thrust reverser 30 according to the invention for use in the nacelle of an aircraft turbojet engine is shown.

[0061] The thrust reverser 30 has a generally annular shape around an axis (not visible), which is the longitudinal axis of the turbojet engine and its nacelle. The thrust reverser 30 includes:

[0062] - Fixed upstream portion 32, which includes an annular frame 34.

[0063] -Downstream annular support 36

[0064] - Deflection vane 38, the upstream end 38a of which is fixed to the frame 34, and the downstream end 38b of which is fixed to the support 36.

[0065] - Fairing 40, which can be... Figure 5 The upstream position shown is shifted to Figure 6 The diagram shows the thrust-reverse downstream position, where the fairing covers and surrounds the blade cascade 38; in the thrust-reverse downstream position, the blade cascade 38 is not covered and is therefore unrestricted.

[0066] - A deflecting element 42 for deflecting the secondary flow F11 of the turbojet engine through the blade cascade 38 when the cowling 40 is in its downstream position, and

[0067] - An actuator 44 with an elongated shape, the upstream end 44a of which is fixed to the fixed portion 32 and the downstream end 44b of which is fixed to the fairing 40.

[0068] In the prior art, deflection element 42 may include a wing 46 associated with link 48.

[0069] The fairing 40 may be similar to existing fairings, which will not be described further.

[0070] Preferably, the actuator 44 is cylindrical. For example, there are two or more actuators evenly distributed around the axis of the thrust reverser. Each actuator 44 includes a fixed body 44c and a movable rod 44c. In the example shown, the body 44c is fixed to a fixed portion 32, and the rod 44c is fixed to one or more fairings 40. Therefore, it should be understood that the upstream end 44a of the body 44c is fixed to the fixed portion 32, while the downstream end 44b of the rod 44c is fixed to one or more fairings.

[0071] Here, the rod 44d is attached to one or more fairings 40 by adding and securing a clamp 50 to one or more fairings 40. The attachment of the body 44c will be described in more detail below.

[0072] The deflection vane cascade 38 is similar to the deflection vane cascade of the aforementioned technology, except that, in the example shown, each of the deflection vane cascades 38 extends in a plane P, which is inclined at an angle α between 5° and 20° relative to the axis of the thrust reverser. Figure 6 ).

[0073] As can be seen, the plane P of the blade cascade 38 is transversely traversed by the actuator 44. Specifically, as in... Figure 9 and Figure 10 As can be seen, each actuator 44 passes between the opposing longitudinal edges of two adjacent blade cascades 38. Therefore, the blade cascades 38 arranged on both sides of the actuator 44 are circumferentially spaced to allow the actuator to pass through. The adjacent blade cascades 38 not arranged on both sides of the actuator are arranged circumferentially side by side.

[0074] Preferably, the support member 36 extends continuously for 360° around the axis of the thrust reverser 30. In the example shown, the support member is formed of a ring.

[0075] The downstream end 38b of the blade cascade 38 is applied to the outer annular surface 36a of the support 36 and is fixed to the support by welding or by, for example, a screw and nut type fixing device. Figure 10 ).

[0076] As can be seen, the support member 36 extends around the actuator 44. Figure 5 and Figure 6 The actuator 44 is shown to be positioned at a certain distance from the support 38.

[0077] The upstream end 38a of the blade cascade 38 is applied to the outer truncated conical surface 52c of the frame 34 and is fixed to the frame by welding or by, for example, screw and nut type fasteners. Figure 7 ).

[0078] Frame 34 only Figure 8 It can be seen in the axial section view and in the perspective view of the following figures.

[0079] Framework 34 includes:

[0080] - A first truncated conical wall 52, which widens in the downstream direction and includes an upstream peripheral edge 52a and a downstream peripheral edge 52b, the downstream peripheral edge extending in a continuation of the wall 52 and including the aforementioned surface 52c, and

[0081] - A second annular wall 54 extends radially outward from the surface 52c.

[0082] According to one feature of the invention, the walls 52, 54 and even other walls of the frame 34 are integrally formed (or as a single material). In fact, one of the objectives of the invention is to produce a one-piece frame 34 without requiring the assembly of components. The frame 34 is made of, for example, aluminum.

[0083] The frame can be continuous 360°, or it can be sectored into two or more consecutive sectors.

[0084] In the context of this invention, frame 34 can be manufactured 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 inner and outer diameters of which correspond, for example, in the range of a few millimeters, to the inner diameter Dint and outer diameter Dext of the frame, for finishing purposes. The maximum thickness of the plate corresponds to the maximum axial dimension Emax1 of the frame. Emax1 is, for example, between 150 mm and 250 mm, preferably between 200 mm and 220 mm. The block or plate is then intended to be machined to form walls 52, 54 and other parts of the frame, which will be described in detail below.

[0085] In the example shown, frame 34 includes a third annular wall 56 that extends radially inward from the inner truncated conical surface 52d of wall 52.

[0086] Wall 56 is also formed integrally with walls 52 and 54.

[0087] In the example shown, the cross-section of wall 56 is generally inverted L-shaped, and the wall includes a radially outer annular leg 56a, the outer periphery of which is connected to face 52d, and the inner periphery of which is connected to an annular flange 56b, which is oriented axially upstream. Leg 56a will have a generally truncated conical shape that opens from downstream to upstream.

[0088] An annular deflector 58 is supported and secured to one side of flange 56b and the downstream end of face 52d. The shroud 58 includes a downstream end 58a, which is flat and applied to face 52d, and the remainder of the shroud is dome-shaped or curved, having concave surfaces oriented radially outward and upstream.

[0089] As in Figure 7 As can be seen, the downstream end 58a of the shield 58 is positioned radially toward the interior of the actuator 44, so that it is not interrupted by any passages required by these actuators.

[0090] As can be seen in the same figure, the upstream end of the blade cascade 38 is parallel to the downstream end 58a. This is because the downstream edge 58b of the wall 52 extends in the continuation of the wall, thus having a truncated conical shape, and when viewed in cross-section, the inner surface 52d and the outer surface 52c of the wall are parallel.

[0091] The opposite upstream edge 52a of the wall 52 (referred to as the J-ring) has a specific cross-sectional shape that allows the opposite upstream edge to be secured to the turbojet engine housing, as is well known to those skilled in the art.

[0092] Wall 54 has a relatively large axial thickness Emax2, and is recessed on its two faces 54a and 54b by machining. Figures 8 to 10 Therefore, wall 54 includes an upstream surface 54a and a downstream surface 54b, the upstream surface including a first recess 60. Figure 10 and Figure 11 The downstream surface includes a second recess 62. Figure 9 and Figure 12 ).

[0093] In the example shown, the number of recesses 60 is the same as the number of actuators 44, because each actuator is designed to pass through an aperture 64 formed in the bottom 60a of the recess 60.

[0094] Each recess 60 has a generally parallelepiped shape and opens 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 parallel to the axis of the thrust reverser. The partitions 66 are connected to the bottom 60a of the recess 60 and are arranged on both sides of the orifice 64. In the radial direction, the two partitions further extend between the surface 52c and the outer periphery of the wall 54.

[0095] Actuators 44 are secured to these partitions 66, which may include two aligned holes 68 for receiving and securing the shaft (not shown) of the actuator 44. Each actuator 44, particularly its end 44a or its cylinder 44c, is secured to the frame 34, and more particularly to the partitions 66 of the frame.

[0096] The recess 62 reduces the weight of the frame 34 while maintaining its mechanical strength. Therefore, as in... Figure 12 As can be seen, the recess 62 of the downstream surface 54b can take the form of multiple cavities defined by the first annular web 68 and the second radial web 70. From Figure 12 It can also be seen that the frame 34 includes reinforcing ribs 72 that extend radially between the inner truncated conical surface 52d and the downstream annular surface 56c of the wall 56.

[0097] The construction of the one-piece frame 34 brings several advantages mentioned above. In particular, the one-piece frame construction avoids the assembly of components. The one-piece frame construction also makes it possible to integrate multiple functions into the frame, especially by fixing it to the housing via edge 52a, fixing it to the blade cascade via edge 52b, allowing the actuator 44 to pass through the orifice 60 of the wall 54, fixing the actuator 44 via the partition 66, reducing the weight of the frame 34 and reinforcing the frame 34 via the webs 68, 70 and ribs 72, and so on.

[0098] The alignment of the blade cascade 38 within the continuation of the truncated conical wall 52 is also advantageous, as this alignment optimizes the flow of the secondary flow F11 through the blade cascade in the reverse thrust position. This alignment brings the upstream end 38a of the cascade 38 closer to the downstream end of the shroud 58, thus guiding the flow as it leaves the shroud and limiting the risk of air separation on the shroud. This alignment can reduce the axial dimension of the shroud to further limit the risk of such separation.

Claims

1. A thrust reverser (30) for the nacelle of an aircraft bypass turbojet engine, the thrust reverser having a generally annular shape about an axis and comprising: - Fixed upstream portion (32), the fixed upstream portion including an annular frame (34). - Downstream annular support (36). - A deflection blade cascade (38), the upstream end (38a) of which is fixed to the annular frame (34), and the downstream end (38b) of which is fixed to the downstream annular support (36). - A fairing (40) that can be translated from an upstream position to a thrust-reversing downstream position, in which the fairing covers the deflector cascade (38) and in which the deflector cascade is not covered at the thrust-reversing downstream position. - A deflecting element (42) for deflecting the secondary flow (F11) of the aircraft bypass turbojet engine through the deflecting vane cascade (38) when the fairing (40) is in the thrust-reverse downstream position of the fairing, and - An actuator (44) having an elongated shape, the upstream end (44a) of which is fixed to the fixed upstream portion (32), and the downstream end (44b) of which is fixed to the fairing (40). The ring frame (34) is characterized in that it comprises: - A first truncated conical wall (52), which widens in a downstream direction and includes an upstream peripheral edge (52a) and a downstream peripheral edge (52b), the upstream peripheral edge being configured to be fixed to the housing of the aircraft bypass turbojet engine, the downstream peripheral edge extending in a continuation of the first truncated conical wall (52) and used to fix the upstream end (38a) of the deflection blade cascade (38), and - A second annular wall (54) extends radially outward from the outer truncated conical surface (52c) of the first truncated conical wall (52). The first truncated conical wall (52) and the second annular wall (54) are integrally formed, and the second annular wall (54) includes an axial orifice (64) through which the actuator (44) passes.

2. The thrust reverser (30) according to claim 1, wherein, The actuator (44) extends parallel to the axis.

3. The thrust reverser (30) according to claim 1 or 2, wherein, Each of the deflection blades (38) extends in a plane (P) inclined at an angle (α) between 5° and 20° relative to the axis.

4. The thrust reverser (30) according to claim 2, wherein, Each actuator (44) extends between two adjacent deflection vane grates (38) and passes through the plane (P) of these deflection vane grates.

5. The thrust reverser (30) according to claim 1 or 2, wherein, The downstream end (44b) of the actuator (44) is surrounded by the downstream annular support (36) in a way that keeps them at a distance from each other.

6. The thrust reverser (30) according to claim 1 or 2, wherein, The second annular wall (54) includes an upstream surface having a first recess (60) and a downstream surface having a second recess (62), wherein the axial orifice (64) is formed at the bottom (60a) of the first recess (60).

7. The thrust reverser (30) according to claim 6, wherein, At least two partitions (66) that are parallel to each other and parallel to the axis extend into each of the first recesses (60), the partitions being connected to the bottom (60a) of the first recess and arranged on both sides of the axial opening (64).

8. The thrust reverser (30) according to claim 7, wherein, The actuator (44) is fixed to the partition (66).

9. The thrust reverser (30) according to claim 6, wherein, The second recess (62) is formed by a plurality of cavities defined by a first annular web (68) and a second radial web (70).

10. The thrust reverser (30) according to claim 1 or 2, wherein, The annular frame (34) includes a third annular wall (56) extending radially inward from the inner truncated conical surface (52d) of the first truncated conical wall, and a reinforcing rib (72) extending radially between the inner truncated conical surface (52d) and the downstream annular surface (56c) of the third annular wall (56).

11. The thrust reverser (30) according to claim 10, wherein, The annular deflection shield (58) is supported and fixed on the inner circumference of the third annular wall (56) and the downstream end of the inner truncated conical surface (52d).

12. A bypass turbojet engine for an aircraft, comprising a thrust reverser (30) according to any one of claims 1 to 11.

Images