Thrust reverser cascade for aero-engine
By adopting an inclined mold-forming wing beam surface in the mold design, the aerodynamic and structural strength problems caused by steps in the injection molding process are solved, and the aerodynamic performance and strength of the blade are improved.
Patent Information
- Application Number
- CN202380094131.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2022-12-29
- Filing Date
- 2023-12-28
- Publication Date
- 2025-10-03
AI Technical Summary
During the injection molding process of existing aviation jet engine thrust reverser blades, due to unreasonable design of the mold demoulding angle, sharp steps appear on the wing beam surface, affecting the aerodynamic performance and structural strength.
An inclined mold design is adopted to shape the large surface of the spar through two mold parts, so that it forms a roughly triangular third sub-surface in the XY and XZ projection planes, avoiding sudden steps in thickness changes and ensuring a smooth transition of the spar surface.
The aerodynamic performance of the blades is improved, airflow interference is reduced, structural strength is enhanced, and stress concentration is avoided.
Smart Images
Figure CN120752429A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a thrust reverser cascade for an aircraft jet engine. Background Art
[0002] A thrust reverser cascade for an aircraft jet engine typically includes a plurality of spars, each spar extending axially along a longitudinal direction X, and the spars being arranged parallel to one another and spaced apart from one another along a transverse direction Y. The cascade also includes a plurality of blade assemblies extending between the spars along the transverse direction Y and spaced apart from one another along the longitudinal direction X. The blade assemblies, together with the spars, define a plurality of cavities through which a thrust reverser airflow can flow to perform the thrust reverser function of the jet engine. Each blade assembly extends transversely along the transverse direction Y between two consecutive spars, and each blade assembly is connected to the two consecutive spars by two corresponding connecting edges facing away from one another. Each blade assembly also extends along a direction Z perpendicular to the longitudinal direction X and the transverse direction Y, from an edge referred to as a leading edge to an oppositely facing edge referred to as a trailing edge, and extends with a certain curvature so as to form an aerodynamic profile of the blade assembly between the two edges.
[0003] This thrust reverser cascade can be manufactured by injection molding using a so-called "draft" shape that facilitates integral demolding. In practice, the molding of multi-cavity cascades causes material shrinkage, making it necessary to have a draft angle relative to the demolding direction in order to avoid any indentations, entrapments, or cavities that could hinder straightforward demolding of the part.
[0004] To facilitate demolding of such a multi-cavity thrust reverser cascade, each mold tool includes a positive draft angle, particularly to shape the facing faces of the spar with the airfoil disposed transversely therebetween.
[0005] However, according to this design, the junction of the surfaces that are drafted relative to the demoulding direction forms a sharp step in the two facing faces of the spar in the form of a transverse indentation on this surface. This indentation is oriented obliquely, starting from the longitudinal edge of the spar close to the leading edge of the blade component, in the direction of the longitudinal edge facing away from the spar, to an area located near the outer arc surface of the next blade component and at a distance from this longitudinal edge facing away from the blade component.
[0006] Such locally shaped spar surfaces affect the aerodynamic performance of the cascades, as the airflow over them encounters these sharp steps, creating aerodynamic drag phenomena. Furthermore, these local shapings create concentrations of mechanical stresses that can affect the structural strength of the cascades.
[0007] In view of the above circumstances, it would be of great significance to be able to manufacture thrust reverser blades for aircraft jet engines by injection molding and to improve the aerodynamic performance and structural strength of the blades. Summary of the Invention
[0008] Therefore, the present invention relates to a thrust reverser cascade for an aircraft jet engine, comprising:
[0009] a plurality of spars, each extending along a longitudinal direction X and spaced apart from one another along a transverse direction Y, each spar also extending along a direction called height Z, perpendicular to the longitudinal direction X and the transverse direction Y, each spar comprising two large faces facing away from one another;
[0010] a plurality of blade assemblies, each blade assembly extending between the spars along the transverse direction Y, the blade assemblies arranged between two spars facing each other being spaced apart from each other along the longitudinal direction X;
[0011] Each of the two oppositely facing large faces of each spar comprises two sub-surfaces SS1, SS2 situated between two consecutive blade assemblies spaced apart along the longitudinal direction X and each connected to the associated large face of the spar, the two sub-surfaces being longitudinally offset relative to one another along the longitudinal axis X and forming together, according to the projection in the plane XY, a non-zero angle α of less than 90°, the two sub-surfaces SS1, SS2 being connected to one another by a third sub-surface SS3 having, according to the projection in the plane XZ, a substantially triangular shape with an apex situated in the lower part of the spar and a base situated in the top of the spar and longitudinally offset relative to the position of the apex.
[0012] When considering a view in plane XY (where the second sub-surface is inclined relative to the first sub-surface), the third sub-surface, which has a generally triangular shape in its projection into plane XZ, allows for a gradual transition from the first sub-surface to the second sub-surface, rather than having a third sub-surface extending transversely in an abrupt manner (step) as in the prior art. This shaping of the opposing large faces of the spar is achieved with the aid of two mold parts, which are suitably shaped to have adjacent surfaces extending in an inclined manner in the longitudinal and transverse directions, so as to produce adjacent draft surfaces on each large face of the spar. These adjacent draft surfaces join together to form a third sub-surface of the relevant large face having a generally triangular shape in its projection into plane XZ. Consequently, the change in thickness of the spar between the two blade assemblies is gradual, without sharp steps. This avoids stress concentrations caused by abrupt thickness changes, and the air flowing between the two blade assemblies along each of the two opposing large faces of the spar is less disturbed than before.
[0013] According to other possible characteristics, alone or in combination:
[0014] - according to the projection in the plane XY, the two sub-surfaces SS1, SS2 together form a non-zero angle of less than 10°, preferably less than 5°;
[0015] - each spar comprises two opposite longitudinal edges, each longitudinal edge connecting two opposite large faces of the spar to one another, the base of the substantially triangular shape of the third sub-surface SS3 of each large face of the spar being positioned, according to the projection in the plane XZ, on a longitudinal edge situated in the top of the spar, called the upper edge;
[0016] - the vertex of this substantially triangular shape is situated, according to the projection in the plane XZ, at a distance from the opposite longitudinal edge of the spar, called the lower edge;
[0017] - the substantially triangular shape of the third sub-surface SS3 of each large face of the spar, according to the projection in the plane XZ, comprises a side of the triangle adjacent to the second sub-surface SS2 and inclined at an angle β relative to the lower edge of the spar, this angle β being between 10° and 80°, preferably between 30° and 70°;
[0018] - the substantially triangular shape of the third sub-surface SS3 of each large face of the spar, according to the projection in the plane XZ, comprises another side of the triangle adjacent to the first sub-surface SS1 and inclined at an angle greater than the angle β and less than or equal to 90° relative to the lower edge of the spar;
[0019] - the third subsurface SS3 of each large face of each spar is planar according to the projection in the plane XY;
[0020] - the third subsurface of each large face of each spar is convex according to the projection in the plane XY;
[0021] - Two consecutive blade components spaced apart along the longitudinal direction X together define a cavity through which an airflow can pass, the first blade component comprising an outer camber-forming surface oriented towards the cavity, and the second blade component comprising an inner camber-forming surface oriented towards the cavity, the first sub-surface SS1 of the two sub-surfaces SS1 and SS2 of the associated large surface of the spar being adjacent to the first blade component and the second sub-surface SS2 being adjacent to the second blade component. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Other characteristics and advantages of the present disclosure will emerge from the following description of an embodiment given as a non-limiting example, with reference to the accompanying drawings.
[0023] [ Figure 1 ] Figure 1 is a general schematic diagram of a thrust reverser cascade for a jet engine according to one embodiment of the present invention;
[0024] [ Figure 2 ] Figure 2 yes Figure 1 An enlarged schematic diagram of a portion of a blade cascade;
[0025] [ Figure 3 ] Figure 3 yes Figure 2 Schematic diagram of the projection of the cascade part in the plane XZ;
[0026] [ Figure 4 ] Figure 4 yes Figure 2 A partial schematic top view of the cascade portion of FIG. 1 in projection into the plane XY;
[0027] [ Figure 5 ] Figure 5 It is similar to the prior art Figure 2 A schematic diagram of a cascade portion of a cascade portion;
[0028] [ Figure 6 ] Figure 6 is shown for manufacturing Figure 1 A general schematic top view of one possible exemplary embodiment of a portion of a mold for a cascade blade;
[0029] [ Figure 7 ] Figure 7 It is used for manufacturing Figure 1 An enlarged overall schematic partial view of two nested parts of a cascade mold (closed mold);
[0030] [ Figure 8 ] Figure 8 It is along Figure 7 Overall partial schematic diagram of section VIII-VIII. DETAILED DESCRIPTION
[0031] A possible embodiment of a thrust reverser cascade 10 for an aircraft jet engine is Figure 1, shown in a perspective top view, generally comprises: a plurality of longitudinal (axial) spars 12, each extending in a longitudinal direction X and spaced apart from one another in a transverse direction Y; and a plurality of blade assemblies 14, each extending transversely between the spars 12 in the transverse direction Y. Blade assemblies disposed between two facing spars are spaced apart from one another in the longitudinal direction X. The blade assemblies 14 intersect with the spars 12 to which they are connected, collectively forming a cascade structure when viewed in plane XY. Each spar 12 also extends in a third direction, referred to as height, Z, which is perpendicular to the longitudinal and transverse directions Y. Therefore, the cascade 10 also extends in a direction Z perpendicular to the first two directions X and Y, depending on its height. To the extent that the blade assemblies are aerodynamic profiles, they also extend in plane XZ. The cascade 10 also includes a forward flange 16 and a rearward flange 18, disposed at opposite ends of the cascade in the longitudinal direction X. These flanges 16 and 18 are used to secure the cascade to the nacelle of an aircraft jet engine.
[0032] Figure 2 Shown Figure 1 An enlarged partial perspective top view of the blade cascade. Figure 2 , two consecutive blade assemblies 14 spaced apart in the longitudinal direction X together define a cavity C through which an airflow can pass when the cascade is implemented to generate a reverse thrust flow. The two blade assemblies are each connected to two parallel spars 12 opposite each other, and the assembly formed by the blade assemblies and the spar portions located between them defines a so-called unit cell of the cascade.
[0033] More specifically, the two consecutive blade assemblies 14 include a first blade assembly 14.1 and a second blade assembly 14.2. The first blade assembly 14.1 includes an outer arc-forming surface Se1 oriented toward the cavity C, while the second blade assembly 14.2 includes an inner arc-forming surface Si2 oriented toward the cavity C. Figure 2 The represented elements form the projection of the assembly in the plane XZ Figure 3 As shown, the two blade assemblies further include an inner camber-forming surface Si1 for blade assembly 14.1 and an outer camber-forming surface Se2 for blade assembly 14.2. Each blade assembly 14 further includes a leading edge ba and a trailing edge bf connected to each other by aerodynamically contoured surfaces forming the inner camber and outer camber of each blade assembly. Alternatively, the positions of the leading and trailing edges may be reversed.
[0034] Each spar 12 comprises two oppositely facing large faces 12.1 and 12.2, which are substantially parallel to each other and extend in directions X and Z in their projection into the plane XZ. Figure 3In the background, one of the two large surfaces facing each other is shown 12.1.
[0035] Each spar 12 also comprises two opposite longitudinal edges 12.3 and 12.4 (the opposite small faces of the spar), each edge connecting the two opposite large faces 12.1 and 12.2 of the spar to each other so as to define the width or thickness of the spar in the transverse direction Y. One of the two edges is located at the top of the spar and therefore at the top of the cascade when it is as Figure 1 In the arrangement shown, its height is aligned along the axis Z and is referred to as the upper longitudinal edge 12.3; while the other opposite edge is located in the lower part of the spar and therefore in the lower part of the cascade, below the upper edge and is referred to as the lower longitudinal edge 12.4 ( Figure 3 ).
[0036] Each of the two oppositely facing large surfaces 12.1, 12.2 of each spar 12 is formed in a manner such as Figure 2 and Figure 3 Two consecutive blade assemblies 14 . 1 , 14 . 2 , each of which is connected to a related large face of the spar, comprise between them two sub-surfaces SS1 , SS2 , which are longitudinally offset from one another along the longitudinal axis X.
[0037] like Figure 2 and Figure 3 As presented in FIG, a first sub-surface (denoted as SS1 ) of the two sub-surfaces SS1 , SS2 is arranged adjacent to the first blade component 14 . 1 , while a second sub-surface (denoted as SS2 ) is arranged adjacent to the second blade component 14 . 2 .
[0038] Figure 4 The top view of the cascade shows the projection in the plane XY. Figure 2 and Figure 3 , and in particular, the two sub-surfaces SS1 and SS2 together form a non-zero angle α of less than 90°. This angle explains why each large spar face is non-planar. In practice, the two sub-surfaces SS1 and SS2 together form an angle α of less than 10°, preferably less than 5°. This angle is used to release the components of the cascade during its manufacture by injection molding.
[0039] like Figure 2 and Figure 3 As presented in FIG, the two sub-surfaces SS1, SS2 are connected to each other via a third sub-surface SS3. According to the projection diagram in the plane XZ ( Figure 3), the third sub-surface SS3 has a generally triangular shape. This triangle is characterized by a vertex S, a base B, and two sides C1 and C2 adjacent to the vertex S. The vertex S is located in the lower portion of the spar, near but at a distance from the lower longitudinal edge 12.4, while the base B is located in the lower portion of the spar, in this case, on the upper longitudinal edge 12.3. The triangle is tilted such that its base B is longitudinally offset in the direction of the inner arc surface of the second blade component 14.2 toward the cavity C relative to the position of the vertex S, which is longitudinally offset in the direction of the outer arc surface of the first blade component 14.1 toward the cavity.
[0040] According to the projection diagram in plane XZ ( Figure 3 ), the side C1 of the triangle adjacent to the second sub-surface SS2 is inclined relative to the lower edge 12.4 of the spar at an angle β between 10° and 80°, preferably between 30° and 70°. It will also be noted that the opposite side C2 of the triangle adjacent to the first sub-surface SS1 is inclined relative to the lower edge 12.4 of the spar at an angle greater than the angle β and less than or equal to 90°. Thus, the extension area of the third sub-surface SS3 can be more or less extended according to circumstances and needs.
[0041] As described above and shown in the figures, the third sub-surface SS3 defines a transition sub-surface between the two sub-surfaces SS1 and SS2 in a certain way, which ensures that the inclination of the large face 12.1 of the spar increases gradually ("gently") to transition from the inclination of sub-surface SS1 to that of sub-surface SS2.
[0042] For comparison purposes, Figure 5 The prior art schematically presented in (this perspective is similar to Figure 2 ) shows a third sub-surface between two sub-surfaces S1 and S2 of the large face of a spar L, forming a step M extending transversely relative to the spar. This step is formed on the large face of the spar due to the limitations of manufacturing the cascade blades by injection molding, which requires a draft angle for releasing the component from the mold. This configuration results in the large face of the spar having an uneven (non-smooth) surface, causing disruptions in the airflow flowing through the cavity and along the large face, and thus causing pressure losses.
[0043] In contrast, in the configuration of the above-described embodiment, the third sub-surface SS3 is smooth, or in any case does not include any surface such as Figure 5 In this exemplary embodiment, the third inclined sub-surface SS3 ( Figure 4 ) is planar, but can also be convex.
[0044] The thrust reverser blade cascade described above may be manufactured by injection molding using at least two manufacturing molds M1 and M2 .
[0045] Figure 6 A portion of a mold M1 is shown very schematically in a top view and comprises a base or support surface 20 from which a plurality of protrusions 22 extend and away from the surface (direction of extension of the protrusions Z). These protrusions are spaced apart from one another so as to form a matrix according to a projection in a plane XY.
[0046] The portion of mold M2 includes a similar configuration, also having a support / surface from which a plurality of protrusions extend away from the surface, the protrusions also being spaced apart from one another to form a similar configuration. Figure 6 The matrix in .
[0047] The shapes and positions of the protrusions 18 of the mold M1 and the protrusions of the mold M2 in the plane XY are different from and complementary to each other.
[0048] like Figure 7 As represented, the two mould parts M1 and M2 are positioned head to tail relative to each other. Figure 6 Component M1 has been flipped over and positioned above component M2, wherein the respective base / support surfaces 20 and 24 are generally oriented horizontally (ie, Figure 2 The two mold parts are arranged horizontally in the plane XY of the mold M1 and are combined together along the vertical axis Z so that the protrusion 22 of the mold M1 is inserted into or between the protrusions 26 of the other mold M2, and the two mold parts are locally abutted against each other to close the mold.
[0049] like Figure 7 As shown in , according to the projection in the plane XZ, each protrusion 22 comprises two inclined walls 22a, 22b in the direction of the flat apex 22c of the protrusion 22, which two inclined walls join and form a planar support. One of the walls 22a is straight, while the other wall 22b is concave. The two walls extend from two planar portions 22d, each of which forms a support portion of the base / support surface 20 on one side of each protrusion 22. Each of the two inclined surfaces 22a, 22b has an open surface relative to the demoulding axis or direction D, that is, these surfaces do not include local sections of the bottom cut type relative to the direction D. The inclined surface 22a generally has an opening angle of at least 1° to 2°. The demoulding axis or direction is the axis or direction along which the two parts of the mold are separated from each other in order to demould the part manufactured by molding in the mold.
[0050] According to the projection diagram in plane XZ ( Figure 7), the protrusions 26 of the mold M2 each include two inclined walls 26a, 26b in the direction of the flat apex 26c of the protrusion 26, which are joined and form a planar support. One of the walls 26a is straight, while the other wall 26b is convex. Wall 26a extends from a planar portion 26d of the support portion forming the base / support surface 24, while wall 26b extends from a downward indentation formed from the support portion 26d, which is used to form the leading edge of the blade assembly. Each of the two inclined surfaces 26a, 26b has an open surface relative to the demoulding axis or direction D, that is, these surfaces do not include undercut local sections relative to the direction D. The inclined surface 26a typically has an opening angle of at least 1° to 2°.
[0051] The curvatures of the two curved walls 22b and 26b are different from each other, so that Figure 7 In the final closed position (closed mold), the two walls are longitudinally spaced apart from each other and together define a transverse cavity Ct in which the transverse blade components of the cascade will be formed after the injection molding material is injected into the mold through a duct (not shown here) and fills the various cavities (particularly the transverse cavity Ct). For each pair of walls 22b and 26b, the two facing walls 22b and 26b define, respectively, the outer and inner camber surfaces of the future blade component, and their respective curvatures together define (in the plane XZ) the curvature of the aerodynamic profile of the blade component, the degree of which can be adjusted to a greater or lesser degree depending on the selected cascade configuration.
[0052] In addition, Figure 7 In the closed mold position, the base / support surfaces 20, 24 and the corresponding supporting supports 22d, 22c, 26c, 26d are in contact with each other, thereby forming a joint plane. It is particularly noteworthy that the two inclined straight walls 22a and 26a (with the same inclination) of two adjacent protrusions 22 and 26 are arranged to abut against each other and define the closed inclined surface of the mold. Similarly, the corresponding opposing supports 22d and 26c, 22c and 26d are also arranged to abut against each other and define two corresponding closed support surfaces of the mold. In the example shown, these surfaces are planar, but these surfaces can optionally adopt different shapes. The sum of the dimensions of the support 22d, the surface 22a, the support 22c and the surface 22b along the axis X determines the so-called longitudinal "pitch" (along X) between the two blade assemblies. The inclination of the closed inclined surface (inclined surface 22a, 26a) directly affects the pitch between the blade assemblies, just like the dimension of the closed support surface along the direction X (length).
[0053] Figure 8 Schematically shows the Figure 7 In the cross section of the section VIII-VIII, Figure 7The figure also shows two adjacent protrusions 22, 26, which are in contact with each other via respective inclined surfaces 22a and 26a. The figure also shows another pair of protrusions 22', 26' in contact with each other. These two pairs of protrusions are spaced apart from each other transversely (along Y) and thus together define a space E in which the future spar will be formed. This space E also extends along the axis X to define the length of the spar, and along the vertical axis Z to define the height of the spar. Figure 8 The portion of the space E shown in corresponds to the portion of the spar located between two consecutive blade assemblies and is located between two consecutive blade assemblies. Figures 2 to 4 is visible.
[0054] Figure 8 More specifically, the general shape of the two protrusions 22 and 26 in a top view is shown, and in section VIII-VIII, it is shown that the protrusion 22 includes a straight surface 22e and an inclined surface 22f on one of its opposite sides in the plane XY. As shown by the dotted line, the inclined surface 22f extends in the direction X and also in the direction Z (although in the Figure 8 (not shown) extends to define a surface of the third sub-surface SS3, which is relative to the plane XZ and relative to the plane XY ( Figures 1 to 3 ) are inclined surfaces. The inclination of the inclined surface relative to the longitudinal direction X is Figure 4 The bases B of the triangles in the figure have the same inclination. Figure 8 The bottom of the figure has the same structure.
[0055] The portion of the protrusion 26 has a generally trapezoidal profile, wherein the side surface 26e is inclined to define a second sub-surface SS2 inclined along the plane XY relative to the first sub-surface SS1. The side surface 26e is also inclined in the plane YZ, but this is Figure 8 Not shown.
[0056] Thus, the mould construction just described allows the construction of the surface defining the large face 12.1 of the spar, which is provided at Figures 2 to 4 between two consecutive blade assemblies 14.1 and 14.2.
[0057] The manufacture of the thrust reverser blades by injection molding using the aforementioned mold requires, in particular, the introduction of a known type of injection molding material, such as a thermoplastic or short-fiber-reinforced thermoplastic material, into the mold so that the material is distributed in the various longitudinal and transverse cavities defined between the two mold parts. After the material solidifies, the blades are demolded by removing the molded part from one mold part and the other mold part along the aforementioned demolding axis or direction D.
[0058] Although this specification refers to specific exemplary embodiments, these examples may be modified without departing from the general scope of the invention as defined by the claims. Furthermore, the features of the various embodiments shown or mentioned may be combined in other embodiments. Accordingly, the specification and drawings are to be regarded as illustrative rather than restrictive.
Claims
1. A thrust reverser cascade for an aircraft jet engine, comprising: - a plurality of spars (12), each extending along a longitudinal direction (X) and spaced apart from one another along a transverse direction (Y), each spar also extending along a direction (Z) called height, perpendicular to the longitudinal direction (X) and the transverse direction (Y), each spar comprising two large faces (12.1, 12.2) facing away from one another, a plurality of blade assemblies (14, 14.1, 14.2), each blade assembly extending between the spars (12) along the transverse direction (Y), the blade assemblies arranged between two spars facing each other being spaced apart from each other along the longitudinal direction (X), Each of the two oppositely facing large faces (12.1, 12.2) of each spar (12) comprises two sub-surfaces (SS1, SS2) located between two consecutive blade components (14.1, 14.2) spaced apart along the longitudinal direction (X) and each connected to the associated large face of the spar, the two sub-surfaces being longitudinally offset relative to each other along the longitudinal axis (X) and forming together a non-zero angle α of less than 90° according to the projection in the plane (XY), the two sub-surfaces (SS1, SS2) being connected to each other by a third sub-surface (SS3) having, according to the projection in the plane (XZ), a generally triangular shape having an apex (S) positioned in the lower part of the spar and a base (B) positioned in the top of the spar and longitudinally offset relative to the position of the apex (S).
2. The thrust reverser cascade according to claim 1, wherein: According to projection in the plane (XY), the two sub-surfaces (SS1, SS2) together form a non-zero angle of less than 10°, preferably less than 5°.
3. The thrust reverser cascade according to claim 1 or 2, wherein: Each spar (12) comprises two opposite longitudinal edges (12.3, 12.4), each longitudinal edge connecting two oppositely facing large faces (12.1, 12.2) of the spar to each other, the base (B) of the substantially triangular shape of the third subsurface (SS3) of each large face of the spar being positioned on a longitudinal edge situated in the top of the spar, called the upper edge (12.3), according to the projection in the plane (XZ).
4. The thrust reverser cascade according to claim 3, wherein: According to the projection in the plane (XZ), the vertex (S) of the substantially triangular shape is located at a distance from the opposite longitudinal edge of the spar, called the lower edge (12.4).
5. Thrust reverser cascade according to the preceding claim, wherein: The substantially triangular shape of the third subsurface (SS3) of each large face (12.1, 12.2) of the spar comprises, according to the projection in the plane (XZ), a side (C1) of the triangle adjacent to the second subsurface (SS2) and inclined at an angle β relative to the lower edge (12.4) of the spar, said angle β being between 10° and 80°, preferably between 30° and 70°.
6. The thrust reverser cascade according to claim 5, wherein: The substantially triangular shape of the third subsurface (SS3) of each large face (12.1, 12.2) of the spar comprises, according to the projection in the plane (XZ), another side (C2) of the triangle, said other side (C2) being adjacent to the first subsurface (SS1) and being inclined at an angle greater than the angle β and less than or equal to 90° relative to the lower edge (12.4) of the spar.
7. A thrust reverser cascade according to any one of the preceding claims, wherein: According to the projection in the plane (XY), the third subsurface (SS3) of each large face (12.1, 12.2) of each spar is planar.
8. The thrust reverser cascade according to any one of claims 1 to 6, wherein: According to the projection in the plane (XY), the third subsurface (SS3) of each large face (12.1, 12.2) of each spar is convex.
9. A thrust reverser cascade according to any one of the preceding claims, wherein: Two consecutive blade assemblies (14.1, 14.2) spaced apart along the longitudinal direction (X) together define a cavity (C) capable of being passed through by an airflow; the first blade assembly (14.1) includes an outer arc-forming surface (Se1) oriented toward the cavity, and the second blade assembly (14.2) includes an inner arc-forming surface (Si2) oriented toward the cavity; the first sub-surface (SS1) of the two sub-surfaces (SS1, SS2) of the relevant large surface of the wing beam is adjacent to the first blade assembly (14.1), and the second sub-surface (SS2) is adjacent to the second blade assembly (14.2).