Arrangement for an aircraft with a wing and an engine pylon for coupling a propulsion system to the wing

Description

TECHNICAL FIELD

[0001] The present invention relates to an assembly for an aircraft which comprises a wing and a powerplant for coupling a propulsion system to the wing, as well as to an aircraft comprising a propulsion system and such an assembly for coupling the propulsion system to the wing.

[0002] The state of the art is illustrated by document US 2015 / 0251768 A1. STATE OF THE PRIOR ART

[0003] Typically, for an aircraft, a propulsion system includes, for example, a turbojet engine that is attached to a wing of the aircraft using a jet engine pylon. The jet engine pylon generally consists of a primary structure formed by a box consisting of an upper spar, a lower spar and two side panels connecting the two spars and internal ribs distributed along the box.

[0004] The turbojet engine is fixed under the engine pylon to the engine attachment means which conventionally comprise, at the front, a front engine attachment, at the rear, a rear engine attachment, and between the front and rear engine attachments, a thrust force recovery assembly comprising recovery rods fixed between the turbojet engine and the primary structure of the pylon, to absorb the thrust forces generated by the turbojet engine.

[0005] The engine pylon is further attached to the wing structure using a mounting base. More specifically, the mounting base has a substantially inverted U shape and is intended to receive the rear end of the box. The base also carries the attachments of the engine pylon to secure the latter to the wing structure using fittings through which the forces from the turbojet are transmitted to the wing structure.

[0006] Although current installations are satisfactory, the size of turbojets is increasing, but it is not preferable to modify the dimensions of the landing gear so as to modify the height of the wing above the ground for reasons of weight and space penalties. However, the box has relatively large dimensions which make it difficult to position the turbojet under the wing.

[0007] It is therefore necessary to provide a solution ensuring optimal installation of turbojets under the wings of the aircraft. STATEMENT OF THE INVENTION

[0008] An object of the present invention is to propose an assembly for an aircraft comprising a wing and a reactor mast for coupling a propulsion system to the wing and which comprises means of attachment to the wing which make it possible to reduce the size of the reactor mast while ensuring an optimized transfer of forces to the structure of the wing.

[0009] For this purpose, an assembly is proposed for mounting on an aircraft a propulsion system having a vertical median plane, said assembly comprising: a wing with a front spar, an upper surface panel fixed to the upper part of said front spar and a lower surface panel fixed to the lower part of said front spar, where the front spar carries a first fitting at the level of the vertical median plane, where the lower surface panel carries two second starboard and port fittings at a lower part of said front spar, and where the lower surface carries a third fitting positioned to the rear of the second starboard and port fittings, a reactor pylon comprising a primary structure, a shackle fixed by a fifth connection to said third fitting of said lower surface, said fifth connection having at least one degree of freedom in rotation, a first and a second connecting rod, where a first end of each first and second connecting rod is fixed to the shackle respectively by a third and a fourth pivot connection, a third connecting rod, where a first end is fixed to the first fitting by a seventh connection,said seventh connection having at least one degree of freedom in rotation, and a fixing base comprising a body secured to a rear part of the primary structure.

[0010] Said body comprises two first starboard and port fixing clevises extending to the rear and in the upper part on the sides of said fixing base, each of said first fixing clevises being fixed to one of said second fittings by a first pivot connection.

[0011] Said body also comprises two second starboard and port fixing yokes extending to the rear and in the lower part on the sides of said fixing base, each of said two second fixing yokes being fixed by a second connection to a second end respectively of the first and second connecting rods. Said second connection has at least one degree of freedom in rotation.

[0012] Said body further comprises at least a third central fixing yoke extending to the rear and at the level of the vertical median plane, said third central fixing yoke being fixed to a second end of said third connecting rod by a sixth connection, said sixth connection having at least one degree of freedom in rotation.

[0013] The assembly comprises a fourth starboard fitting and a fourth port fitting, each of said fourth fittings being fixed to the primary structure of the engine pylon. For each fourth fitting, the assembly comprises a fourth connecting rod, a first end of which is fixed to said fourth fitting by an eighth pivot connection.

[0014] Furthermore, said body comprises two fourth starboard and port fixing clevises extending at the front and in the lower part on the sides of said fixing base, each of said fourth fixing clevises being fixed to a second end of a fourth connecting rod by a ninth pivot connection.

[0015] With such a reactor mast, the engine forces that are carried by the primary structure of the mast are transmitted directly to the upper and lower panels via the mounting base. In addition, the implementation of the fourth connecting rods connecting the primary structure of the reactor mast to the mounting base makes it possible to reduce the dimensions of the primary structure of the reactor mast, thus allowing and facilitating the attachment of turbojet engines of larger dimensions to the aircraft wing.

[0016] Advantageously, said primary structure comprises an upper spar, a lower spar and two starboard and port side panels connecting the two spars, said fourth fittings being fixed on either side of said primary structure in the lower part of said side panels.

[0017] According to a particular aspect, said body comprises a first inverted U-shaped body portion extending inside a second inverted U-shaped body portion, where the rear portion of the primary structure is fixed in the first body portion, and where the two first fixing yokes, the two second fixing yokes and the two fourth fixing yokes are integral with the second body portion.

[0018] According to another particular aspect, said first body part extends inside said second body part, said first body part and said second body part extending in the same plane, parallel to the vertical plane.

[0019] According to yet another particular aspect, said body comprises at least one reinforcing rib connecting said first body part and said second body part.

[0020] According to a particular aspect, said rear part of the primary structure secured to said fixing base has a height measured in the vertical direction between said upper and lower side members and a width measured in the transverse direction between said side panels, and said fixing base has a height measured between the orthogonal projection of an axis of a second connection of said second fixing yoke and an axis of a sixth connection of said third fixing yoke and a width measured in the transverse direction between said two first fixing yokes, the height of said primary structure being less than the height of said fixing base and the width of said primary structure being less than the width of said fixing base.

[0021] According to a particular aspect, said first body part of said fixing base comprises a first port protrusion and a first starboard protrusion extending vertically in a plane generally perpendicular to the vertical median plane, said first protrusions being arranged on either side of said primary structure in the upper part of said side panels. For the first port protrusion, the assembly comprises a first connecting rod, a first end of which is fixed to said first protrusion by a tenth pivot connection. For the first starboard protrusion, the assembly comprises a second connecting rod, a first end of which is fixed to said first starboard protrusion by an eleventh pivot connection.Said second port and starboard fittings respectively comprise a second port protrusion and a second starboard protrusion extending vertically in a plane generally perpendicular to the vertical median plane, said second protrusions extending in the lower part of the second fittings, the second starboard protrusion being fixed to a second end of said first connecting rod by an eleventh pivot connection and said second port protrusion being fixed to a second end of said second connecting rod by an eleventh pivot connection.

[0022] According to another particular aspect, said tenth and eleventh pivot links have an adjusted link axis and at least one of said twelfth and thirteenth pivot links has a link axis comprising play.

[0023] According to a particular aspect, said second, fourth, fifth and sixth links are pivot links or ball joints.

[0024] The invention also provides an aircraft comprising a propulsion system and an assembly as described above, where the propulsion system is attached to the engine pylon. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above-mentioned and other features of the invention will become more clearly apparent from the following description of an exemplary embodiment, said description being made in relation to the accompanying drawings, among which: [ Fig. 1 ] is a side view of an aircraft according to the invention; [ Fig. 2 ] is a perspective view of an assembly according to one embodiment of the invention; [ Fig. 3 ] is a side view of the Fig. 2 ; And [ Fig. 4 ] is a rear view partially illustrating the whole of the Figs. 2 And 3 . DETAILED DESCRIPTION OF AN EMBODIMENT METHOD

[0026] There Fig. 1 shows an aircraft 10 which comprises a propulsion system 102, for example of the turbojet or turboprop type. The propulsion system 102 is linked to a wing 104 of the aircraft 10 via a reactor mast 106. The wing 104 and the reactor mast 106 form an assembly 100 according to the invention and the propulsion system 102 is fixed to the reactor mast 106 by any suitable fixing means known to those skilled in the art such as those disclosed in document US-A-2016 / 0221682.

[0027] In the following description, terms relating to a position are taken with reference to an aircraft in a normal flight position, that is to say as it is represented on the Fig. 1 and the "forward" and "rear" positions are taken relative to the front and rear of the propulsion system 102 and relative to the direction of advance F of the aircraft 10 when the propulsion system 102 is operating.

[0028] In the following description, and by convention, we call X the longitudinal direction of the propulsion system which is horizontal when the aircraft is on the ground, we call Y the transverse direction which is horizontal when the aircraft is on the ground, and Z the vertical direction which is vertical when the aircraft is on the ground, these three directions X, Y and Z being orthogonal to each other.

[0029] The reactor mast 106 and the propulsion system 102 have a vertical midplane XZ and the propulsion system 102 is here a turboprop with a propeller 102a, but it could be of the double-flow turbojet type with a nacelle.

[0030] There Fig. 2 shows the assembly 100 according to the invention. The reactor mast 106 comprises a rigid structure forming a box and also called primary structure 202. The primary structure 202 is formed of an upper spar 204, a lower spar 206 and two side panels 208 (only the port panel is shown in the Figs. 2 And 3 ) starboard and port connecting the two longerons 204 and 206.

[0031] The shape of the primary structure 202 is in this example configured so that the reactor mast 106 has a front pyramid 201, located at the front end of the reactor mast 106 in the direction of advance F, and a base 203, substantially rectangular, located at the rear end of the reactor mast 106 in the direction of advance F. The base 203 has a height h measured substantially in the vertical direction Z between the upper 204 and lower 206 side members and a width 1 measured substantially in the transverse direction Y between the two side panels 208.

[0032] The wing structure 104 includes a forward spar 210, an upper surface panel 214 and a lower surface panel 216 which are both attached to the forward spar 210 and extend generally in horizontal planes XY.

[0033] Of course, to ensure the rigidity of the wing, its structure includes other elements such as ribs which are distributed between the extrados panel 214 and the intrados panel 216.

[0034] The front spar 210 here takes the form of a profile in the shape of an inverted Z step on the Figs. 2 And 3, with an upper wing 210a (also called upper part) and a lower wing 210b (also called lower part) which are generally horizontal and a central part 210c generally perpendicular to the median plane and extending generally vertically parallel to the YZ plane. The extrados panel 214 is fixed above the upper wing 210a of the spar 210 and the intrados panel 216 is fixed below the lower wing 210b of the spar 210. The attachment of the front spar 210 to the panels 214 and 216 is carried out by any suitable means such as welds, bolts, etc. The extrados panel 214 is thus fixed in the upper part of the front spar 210 and the intrados panel 216 is fixed in the lower part of the front spar 210. The central part 210c is at the level of the leading edge of the wing 104.

[0035] In order to allow the engine pylon 106 to be fixed to the wing 104, the front spar 210 carries a first fitting 211a fixed at the level of the vertical median plane XZ and more particularly here to the central part 210c of the front spar 210. The lower surface panel 216 carries two second fittings, starboard 211b' and port 211b (only the second port fitting is shown in the drawings). Figs. 2 And 3 , the second starboard fitting is shown on the Fig. 4 ) which are fixed on the external face of the intrados panel 216 and in alignment with the lower part 210b of the front side member 210. In addition, the intrados panel 216 also carries a third fitting 221 (visible on the Fig. 3 ), which is in this example, fixed under the intrados 216, substantially at the level of the lowest part of the intrados 216. In this example, the third fitting 221 is positioned at the rear of the second starboard 211b' and port 211b fittings.

[0036] The assembly 100 further comprises a fixing base 270 secured to the rear part of the primary structure 202. The fixing base 270 comprises in this example a body 270a extending vertically in the YZ plane. More precisely, the body 270a has a first body part 272 in the form of an inverted U as well as a second body part 271 also in the form of an inverted U. The first body part 272 and the second body part 271 extend in a vertical plane parallel to the vertical plane YZ and the first body part 272 is arranged inside the second body part 271.

[0037] In the illustrated example, the first body portion 272 comprises a central upper wall 272a extending horizontally in a plane parallel to the XY plane. The first body portion 272 also comprises two starboard 272b' and port 272b side walls (only the port side wall is shown in the Figs. 2 And 3 , the starboard side wall is visible on the Fig. 4 ) which extend perpendicularly from the central upper wall 272a and which extend vertically in planes parallel to the vertical median plane XZ. The central upper wall 272a and the starboard 272b' and port 272b side walls are integral and extend around and above the rear portion of the primary structure 202 and form a housing 273 for receiving the base 203 of the primary structure 202. The dimensions of the housing 273 are obviously chosen to correspond to the dimensions of the base 203 of the primary structure 202. It is understood that the primary structure 202 is fixed to the housing 273 by any suitable means such as welds, bolts, etc. The fixing base 270 comprises at least one reinforcing rib 272c connecting the walls 272a, 272b, 272b' of the first body part 272 to the second body part 271. In this example, three ribs 272c are implemented (only two ribs are visible on the Fig. 2 ) and extend respectively from the upper central wall 272a and the starboard 272b' and port 272b side walls to the second body part 271. These reinforcing ribs 272c allow in particular the fixing base 270 to support and transmit the forces coming from the propulsion system 102 to the wing 104. The ribs 272c fix the walls 272a, 272b, 272b' of the first body part 272 to the walls of the second body part 271.

[0038] In order to allow the attachment of the engine pylon 106 to the wing 104, the second body part 271 of the body 270a of the attachment base 270 comprises two first starboard and port attachment yokes 273a (only the first port attachment yoke is shown in the Figs. 2 And 3) which extend from the second body part 271 of the body 270a towards the rear and which are arranged in the upper part on the sides of the fixing base 270. Each of the first fixing yokes 273a is secured to one of the second fittings 211b, 211b' by a first pivot connection 283a, in particular a sliding pivot connection.

[0039] In this example, the first fixing yokes 273a and the second fittings 211b, 211b' each comprise a bore into which an axle is threaded to form the first pivot connection 283a. This first pivot connection 283a has a substantially horizontal axis of rotation which extends generally parallel to the transverse direction Y.

[0040] The second body part 271 of the body 270a of the fixing base 270 also comprises two second starboard and port fixing yokes 273b (only the second port fixing yoke is shown in the Figs. 2 And 3) which extend from the second body part 271 of the body 270a towards the rear and which are arranged in the lower part on the sides of the fixing base 270. The two second fixing yokes 273b are integral with a shackle 280 which can be triangular, respectively by a first and a second connecting rod 281a, 281b.

[0041] In this example, the second starboard fixing clevis is fixed to a second end of the first connecting rod 281a by means of a second connection 283b, while the second port fixing clevis 283b is fixed to a second end of the second connecting rod 281b by means of another second connection 283b. The second connection 283b has at least one degree of freedom in rotation about an axis extending here substantially parallel to the transverse direction Y. In this example, the second connection 283b is a pivot connection whose axis extends generally parallel to the transverse direction Y.

[0042] In a variant not illustrated, it would be possible to substitute the second pivot link 283b with a ball joint.

[0043] The first ends of the first 281a and second 281b connecting rods are respectively attached to the shackle 280 by a third 283c and a fourth 283d pivot link. The axis of the third 283c and fourth 283d pivot links extends generally parallel to the direction perpendicular to the plane passing through the axes of the first and second connecting rods 281a, 281b. In this example, the first ends of each two second connecting rods 281a, 281b and the shackle 280 comprise bores into which axes are threaded to form said third 283c and fourth 283d pivot links.

[0044] Furthermore, the shackle 280 is fixed by a fifth connection 283e to the third fitting 221 of the intrados 216. The fifth connection 283e has at least one degree of freedom in rotation along an axis extending here substantially parallel to the vertical direction Z. In this example, the fifth connection 283e is a pivot connection whose axis extends generally parallel to the direction perpendicular to the plane passing through the axes of the first and second connecting rods 281a, 281b. To do this, the shackle 280 and the third fitting 221 each have a bore into which an axis is threaded to form the fifth pivot connection 283e.

[0045] In a variant not illustrated, it would be possible to substitute the fifth 283rd pivot link with a ball joint.

[0046] The second body portion 271 of the body 270a of the fixing base 270 also comprises at least one third central fixing yoke 273c (only one in the illustrated example) which extends from the second body portion 271 of the body 270a towards the rear and which is arranged substantially in a centered manner (i.e. at the level of the vertical median plane XZ) in the upper part of the fixing base 270.

[0047] The third central fixing yoke 273c is fixed to the first fitting 211a by a third connecting rod 282. More precisely, a first end of the third connecting rod 282 is fixed to the first fitting 211a by a seventh connection 283g and the second end of the third connecting rod 282 is fixed to the third central fixing yoke 273c by a sixth connection 283f. The sixth 283f and seventh 283g connections have at least one degree of freedom in rotation about an axis extending here substantially parallel to the transverse direction Y. In this example, the sixth 283f and seventh 283g connections are pivot connections whose axis extends generally parallel to the transverse direction Y.

[0048] To do this, the third connecting rod 282 has a bore at each of its ends in each of which an axis is threaded and cooperates respectively with a bore provided in the third central fixing yoke 273c and in the first fitting 211a to form the sixth 283f and seventh 283g pivot connections.

[0049] In a variant not illustrated, it would be possible to substitute the sixth 283f and seventh 283g pivot links with ball joints.

[0050] According to the invention, the primary structure 202 carries a fourth starboard fitting and a fourth port fitting 301 (only the fourth port fitting is visible in the Figs. 2 And 3). The fourth fittings 301 are fixed on either side of the primary structure 202. In this example, the fourth starboard fitting is fixed to the starboard side panel and the fourth port fitting 301 is fixed to the port side panel 208. Preferably, and as illustrated in the Figs. 2 And 3 , the fourth fittings 301 are fixed in the lower part of the side panels 208 so as to optimize the transmission of forces coming from the propulsion system 102 and passing through the reactor mast 106 towards the wing 104.

[0051] The second body portion 271 of the body 270a of the fixing base 270 further comprises two fourth starboard and port fixing yokes 302 extending at the front and in the upper part on the sides of said fixing base 270. Each of the fourth fixing yokes 302 is fixed to a second end of a fourth connecting rod 303 by a ninth pivot connection 305. The second end of each fourth connecting rod 303 is fixed to a fourth fitting 201 by an eighth pivot connection 304.

[0052] The axis of the eighth 304 and ninth 305 pivot links is generally parallel to the transverse direction Y.

[0053] The implementation of the fourth fittings 301, the fourth fixing yokes 302 and the fourth connecting rods 303 makes it possible to reduce the dimensions of the primary structure 202 of the engine pylon 106 while ensuring an optimized transfer of the forces coming from the propulsion system 102 to the structure of the wing 104 thanks to these additional force paths. Consequently, the reduction in the dimensions of the primary structure 202 of the engine pylon 106 allows and facilitates the installation and fixing of propulsion systems of dimensions larger than the turbojets currently fixed to the wing of the aircraft.

[0054] As illustrated on the Fig. 4, which partially represents the assembly according to a rear view, the assembly 100 further comprises a set of two connecting rods 275a, 275b making it possible to react to the forces coming from the propulsion system 102 essentially in the transverse direction Y. In this example, the fixing base 270 comprises at the level of the first body part 272, a first port protrusion 274a and a first starboard protrusion 274b. In this example, each first protrusion 274a, 274b has an ear shape and extends vertically and perpendicularly to the side walls 272b, 272b', that is to say in a plane perpendicular to the vertical median plane XZ.More specifically, the first port protrusion 274a extends substantially in the corner between the central upper wall 272a and the port side panel 208 of the primary structure 202 and the first starboard protrusion 274b extends substantially in the corner between the central upper wall 272a and the starboard side panel 208 of the primary structure 202. The first protrusions 274a, 274b are arranged in the upper part and in the rear part of the fixing base 270, that is to say at the rear of the primary structure 202.

[0055] The second port fittings 211b and starboard fittings 211b' respectively carry a second port protrusion 274c and a second starboard protrusion 274d. In this example, each second protrusion 274c, 274d also has an ear shape and extends vertically in a plane perpendicular to the vertical median plane XZ. In this example, the second protrusions 274c, 274d extend in the lower part of the second fittings 211b, 211b'.

[0056] In this example, the first protrusions 274a and 274b face each other. In the same way, the second protrusions 274c and 274d also face each other. The set of connecting rods 275a, 275b cross-connects the second fittings 211b, 211b' to the fixing base 270. More precisely, a first connecting rod 275a connects the first port protrusion 274a to the second starboard protrusion 274d while the second connecting rod 275b connects the first starboard protrusion 274b to the second port protrusion 274c. The first 275a and second 275b connecting rods are therefore crossed and extend substantially in two parallel planes perpendicular to the vertical median plane XZ. The two parallel planes are slightly spaced to facilitate the crossing of the first 275a and second 275b connecting rods.

[0057] The ends of the first connecting rod 275a are secured to the first port protrusion 274a and to the second starboard protrusion 274d respectively by a tenth 284a and an eleventh 284b pivot connection. The ends of the second connecting rod 275b are secured to the first starboard protrusion 274b and to the second port protrusion 274c respectively by a twelfth 284c and a thirteenth 284d pivot connection.

[0058] More precisely, the first connecting rod 275a is said to be “engaged” while the second connecting rod 275b is said to be “on standby”. This means that the connecting axes of the tenth 284a and eleventh 284b pivot connections are adjusted and therefore react to the forces under stress, so that the first connecting rod 275a represents the so-called “main” force path for the transmission of forces having a component substantially oriented in the transverse direction Y.

[0059] At least one of the twelfth 284c and thirteenth 284d pivot connections has a clearance which allows, in the event of breakage of the first connecting rod 275a, to engage the second connecting rod 275b so that it is the second connecting rod 275b which reacts to the forces having a component substantially oriented in the transverse direction Y. The second connecting rod 275b thus represents the so-called “secondary” force path.

[0060] For example, the twelfth 284c and thirteenth 284d pivot links each have a connecting pin carried respectively by the first starboard protrusion 274b and by the second port protrusion 274c. At least one of the bores provided at the ends of the second connecting rod 275b and cooperating with these connecting pins has, for example, an oblong shape so that the second connecting rod 275b is mounted with play at at least one of the twelfth 284c and thirteenth 284d pivot links.

[0061] The particular implementation of this set of connecting rods 275a, 275b further allows the dimensions of the primary structure 202 of the engine pylon 106 to be reduced while ensuring an optimized transfer of the forces coming from the propulsion system 102 to the structure of the wing 104. The fixing base 270 has a height H which is measured between the orthogonal projection of the axis of the second fixing yoke 273b and the axis of the third fixing yoke 273c (i.e. vertically in the vertical direction Z) while the width L is measured horizontally (i.e. in the transverse direction Y) between the two first fixing yokes 273a.

[0062] Preferably, and in order to compensate for the lower inertia of the assembly 100, the height h of the primary structure 202 is less than the height H of the fixing base 270 and the width 1 of the primary structure 202 is less than the width L of the fixing base 270.

[0063] In this way, the drainage of the forces passing through the primary structure 202 to the fixing base 270 and the associated connecting rods / shackles is optimized. Indeed, the implementation of a width L of the fixing base 270 greater than the width 1 of the primary structure 202 promotes the absorption of the moment around the vertical axis Z. In the same way, the height H of the fixing base 270 being greater than the height h of the primary structure 202, the points governing the moments around the lateral axis Y are more spaced apart. These two conditions make it possible to optimize the lever arms engaged in the absorption of the moments. This arrangement therefore ensures, locally, an inertia greater than that of the primary structure 202, thus making it possible to limit the dimensions of the primary structure 202.

[0064] It is thus possible to propose a primary structure 202 having a smaller footprint than the primary structures of the solutions of the prior art.

[0065] The primary structure 202, however, has standard dimensions at the level of the front pyramid 201 of the primary structure 202 so as to ensure the compatibility of the assembly 100 with the fixing of propulsion systems currently implemented.

Claims

1. Assembly (100) for the mounting on an aircraft (10) of a propulsion system (102) having a vertical median plane (XZ), said assembly (100) having: - a wing (104) with a front spar (210), a suction-side panel (214) fastened in the top part (210a) of said front spar (210) and a pressure-side panel (216) fastened in the bottom part (210b) of said front spar (210), wherein the front spar (210) bears a first fitting (211a) at the vertical median plane (XZ), wherein said pressure-side panel (216) bears two starboard-side (211b') and port-side (211b) second fittings at the bottom part (210b) of said front spar (210), and wherein the pressure side (216) bears a third fitting (221) positioned at the rear of said starboard-side (211b') and port-side (211b) second fittings, - an engine pylon (106) having a primary structure (202), - a shackle (280) fastened by a fifth connection (283e) to said third fitting (221) of said pressure side (216), said fifth connection (283e) having at least one degree of freedom in rotation, - a first and a second rod (281a, 281b), wherein a first end of each first and second rod (281a, 281b) is fastened to the shackle (280) respectively by a third (283c) and a fourth (283d) pivot connection, - a third rod (282), wherein a first end is fastened to the first fitting (211a) by a seventh connection (283g), said seventh connection (283g) having at least one degree of freedom in rotation, and - a fastening base (270) having a body (270a) as one with a rear part of the primary structure (202), said body (270a) having two starboard-side and port-side first fastening yokes (273a) extending to the rear and in the top part on the sides of said fastening base (270), each of said first fastening yokes (273a) being fastened to one of said second fittings (211b, 211b') by a first pivot connection (283a), said body (270a) also having two starboard-side and port-side second fastening yokes (273b) extending to the rear and in the bottom part on the sides of said fastening base (270), each of said two second fastening yokes (273b) being fastened by a second connection (283b) to a second end respectively of the first and of the second rods (281a, 281b), said second connection (283b) having at least one degree of freedom in rotation, said body (270a) having at least one central third fastening yoke (273c) extending to the rear and at the vertical median plane (XZ), said third central fastening yoke (273c) being fastened to a second end of said third rod (282) by a sixth connection (283f), said sixth connection (283f) having at least one degree of freedom in rotation, the assembly (100) having a starboard-side fourth fitting and a port-side fourth fitting (301), each of said fourth fittings (301) being fastened to the primary structure (202) of said engine pylon (160), for each fourth fitting (301), the assembly (100) having a fourth rod (303) of which a first end is fastened to said fourth fitting (301) by an eighth pivot connection (304), said body (270a) also having two starboard-side and port-side fourth fastening yokes (302) extending to the front and in the bottom part on the sides of said fastening base (270), each of said fourth fastening yokes (302) being fastened to a second end of a fourth rod (303) by a ninth pivot connection (305).

2. Assembly (100) according to Claim 1, said primary structure (202) also having an upper spar (204), a lower spar (206) and two starboard-side and port-side lateral panels (208) connecting the two spars (204, 206), said fourth fittings (301) being fastened on either side of said primary structure (202) in the bottom part of said lateral panels (208).

3. Assembly (100) according to Claim 1 or 2, wherein said body (270a) has a first body part (272) in the form of an inverted U extending inside a second body part (271) in the form of an inverted U, wherein the rear part of the primary structure (202) is fastened in the first body part (272), and wherein the two first fastening yokes (273a), the two second fastening yokes (273b) and the two fourth fastening yokes (302) are as one with the second body part (271).

4. Assembly (100) according to Claim 3, wherein said body (270a) has at least one reinforcing rib (272c) connecting said first body part (272) and said second body part (271).

5. Assembly (100) according to Claim 3, wherein said rear part of the primary structure (202) as one with said fastening base (270) has a height (h) measured in the vertical direction (Z) between said upper (204) and lower (206) spars and a width (1) measured in the transverse direction (Y) between said lateral panels (208), and in that said fastening base (270) has a height (H) measured between the orthogonal projection of an axis of a second connection (283b) of said second fastening yoke (273b) and an axis of a sixth connection (283f) of said third fastening yoke (273c) and a width (L) measured in the transverse direction (Y) between said two first fastening yokes (273a), the height (h) of said primary structure (202) being less than the height (H) of said fastening base (270) and the width (1) of said primary structure (202) being less than the width (L) of said fastening base (270).

6. Assembly (100) according to any one of Claims 3 to 5, wherein said first body part (272) of said fastening base (270) has a port-side first protuberance (274a) and a starboard-side first protuberance (274b) extending vertically in a plane generally perpendicular to the vertical median plane (XZ), said first protuberances (274a, 274b) being disposed on either side of said primary structure (202) in the top part of said lateral panels (208), for the port-side first protuberance (274a), the assembly (100) has a first connecting rod (275a) of which a first end is fastened to said first protuberance (274a) by a tenth pivot connection (284a), for the starboard-side first protuberance (274b), the assembly (100) has a second connecting rod (275b) of which a first end is fastened to said starboard-side first protuberance (274b) by an eleventh pivot connection (284b), and in that said port-side (211b) and starboard-side (211b') second fittings respectively have a port-side second protuberance (274c) and a starboard-side second protuberance (274d) extending vertically in a plane generally perpendicular to the vertical median plane (XZ), said second protuberances (274c, 274d) extending in the bottom part of the second fittings (211b, 211b'), the starboard-side second protuberance (274d) being fastened to a second end of said first connecting rod (275a) by an eleventh pivot connection (284b) and said port-side second protuberance (274c) being fastened to a second end of said second connecting rod (275b) by an eleventh pivot connection (284b).

7. Assembly (100) according to Claim 6, wherein said tenth (284a) and eleventh (284b) pivot connections have a fitted connection pin and in that at least one of said twelfth (284c) and thirteenth (284d) pivot connections has a clearance.

8. Assembly (100) according to Claim 1, wherein said second (283b), fourth (283e), fifth (283f) and sixth (283g) connections are pivot connections or ball joint connections.

9. Aircraft (10) having a propulsion system (102) and an assembly (100) according to any one of Claims 1 to 8, wherein the propulsion system (102) is fastened to the engine pylon (106).