Improved fibrous assembly for double clevis part in composite material

Abstract

Improved fiber assembly for a double-cleated composite material part. The invention relates to a core fiber assembly (100) intended to form the fiber reinforcement of a core (11) of a composite material part (10) comprising a first body (110) and a second body (120), the core fiber assembly (100) being characterized in that it further comprises at least one first connecting fin (111) extending from the first body (110) and a second connecting fin (122) extending from the second body (120), the end portion (111e) of the first connecting fin (111) and the end portion (122e) of the second connecting fin (122) overlapping so as to form an upper connecting portion (100a) linking the upper ends (110a, 120a) of the two bodies (110, 120), the lower ends (110b, 120b) of the two bodies (110, 120) being connected by a lower connecting portion (100b). Figure for the abbreviation: Fig. 6

Description

Title of the invention: Improved fibrous assembly for a double-clamped part made of composite material technical field

[0001] The present invention relates to a part made of composite material intended to be articulated by means of a double clevis with one or more other parts, in particular a connecting rod or a landing gear lever. Previous technique

[0002] Fig. 1 shows a landing gear comprising two pairs of struts 1 and 1', respectively referred to as the main strut pair and the lateral strut pair. These struts are articulated to the landing gear leg 4 and the landing gear frame 5. Each strut 1 and 1' is formed of two connecting rods, as illustrated in Fig. 2. Thus, strut 1 comprises an upper connecting rod 3 and a lower connecting rod 2. The connecting rods of a strut are articulated to each other and to other parts of the landing gear at their ends by means of pivot pins. Such connecting rods are subjected in operation to significant mechanical stresses, primarily in compression and tension, oriented along the longitudinal axis of the part.

[0003] These connecting rods were usually made of steel, aluminum, or titanium alloys. To reduce their weight, they can now be made of composite material. Indeed, manufacturing connecting rods from composite material allows for lighter rods than those made of metal while maintaining good mechanical properties. Composite connecting rods are thus easier to operate during landing gear operation and reduce the aircraft's mass, thereby lowering fuel consumption.

[0004] Documents FR 2 887 601 A1 and FR 3 017 819 describe such connecting rods made of composite material, comprising a web surrounded by a belt, the fibrous reinforcements of the web and the belt being produced by three-dimensional weaving and then co-injected. Documents FR 2 887 601 A1 and FR 3 017 819 describe in particular connecting rods with a double clevis whose web has an "H" cross-section. The resistance to stress of such connecting rods can be improved. Description of the invention

[0005] It was found that a web with an "H" shaped cross-section was not optimal, and that a web with a so-called "box" shaped cross-section was preferable. Indeed, a "box" shaped cross-section improves rigidity and resistance to torsion and in bending of the part. By "box" section, we mean here a section comprising a closed hollow rectangular part, for example a section in the shape of a Roman "II".

[0006] To this end, the invention proposes a fibrous core assembly intended to form the fibrous reinforcement of a core of a part made of composite material comprising a first body and a second body extending lengthwise along a longitudinal direction and each extending along a thickness direction perpendicular to the longitudinal direction between an upper end and a lower end, the fibrous core assembly being characterized in that it further comprises at least one first connecting fin extending from the upper end of the first body along a transverse direction perpendicular to the longitudinal and thickness directions and a second connecting fin extending from the upper end of the second body along the transverse direction,The end portion of the first connecting fin and the end portion of the second connecting fin overlap along the thickness direction, such that the first and second connecting fins form an upper connecting portion linking the upper ends of the two bodies; the fibrous core assembly further comprises a lower connecting portion linking the lower ends of the two bodies.

[0007] Thus, the core fiber assembly has a particularly rigid and torsionally and flexurally resistant "box" cross-section. The overlap of the connecting fins along the thickness direction allows for the transmission of forces between the two connecting fins and excellent compressive and tensile strength of the core fiber assembly in the final part.

[0008] According to a particular aspect of the invention, the fibrous core assembly further comprises a plurality of external fins extending from the upper or lower end of the bodies in the transverse direction opposite the connecting portions.

[0009] Such external fins make it possible to improve the resistance of the part to buckling.

[0010] According to a particular aspect of the invention, the fibrous core assembly further comprises at least a third connecting fin extending from the lower end of the first body in the transverse direction and a fourth connecting fin extending from the lower end of the second body in the transverse direction, the end portion of the third connecting fin and the end portion of the fourth connecting fin overlapping in the thickness direction so that the third and fourth connecting fins form the lower connecting portion.

[0011] According to a first embodiment of the invention, the first body and the fin(s) extending from the upper and lower ends of said first body belong to the same first fibrous preform, and in which the second the body and the fin(s) extending from the upper and lower extremities of said second body belong to the same second fibrous preform.

[0012] Thus, the core fiber assembly comprises only two fiber preforms. This improves both the transmission of forces within the core fiber assembly and its mechanical strength. The small number of fiber preforms constituting the core fiber assembly also simplifies the manufacturing process for said core fiber assembly. Furthermore, the two fiber preforms are nearly identical, which further facilitates manufacturing and reduces production costs even more.

[0013] In particular, the first fibrous preform and the second fibrous preform may be identical.

[0014] According to a second embodiment of the invention, the fibrous core assembly is formed by a single one-piece fibrous preform.

[0015] Thus, the transmission of forces in the fibrous core assembly as well as its mechanical strength are excellent, the latter being made in a single continuous fibrous preform.

[0016] According to a particular aspect of the invention, the thickness along the thickness direction of the end portions of the connecting fins gradually decreases along the transverse direction up to the end of said connecting fins.

[0017] Indeed, when the part is subjected to tension or compression, the forces transmitted through the core fiber assembly promote the separation of the connecting fins. Such a beveled shape allows for a progressive transmission of forces between the connecting fins, which improves the mechanical strength of the core fiber assembly and makes separation of the connecting fins more difficult.

[0018] The invention also relates to a fibrous assembly of a part comprising a fibrous core assembly as described above and a fibrous belt assembly, the fibrous belt assembly surrounding the fibrous core assembly so as to provide at least a first orifice adjacent to the first body along the longitudinal direction and a second orifice adjacent to the second body along the longitudinal direction, the fibrous belt assembly surrounding the orifices, the first and second orifices being coaxial.

[0019] Furthermore, the invention relates to a mechanical part made of composite material whose fibrous reinforcement is formed by the fibrous assembly of the part as described above densified by a matrix, the fibrous assembly of the core densified by the matrix forming a core and the fibrous assembly of the belt densified by the matrix forming one or more belts surrounding the core and the coaxial orifices so as to form at least a double cap.

[0020] The invention relates to a method for manufacturing a fibrous core assembly intended to form the fibrous reinforcement of a core of a part made of composite material, comprising:

[0021] - the production by weaving of a first body and a second body extending in length along a longitudinal direction and each extending along a thickness direction perpendicular to the longitudinal direction between an upper end and a lower end, of at least a first connecting fin extending from the upper end of the first body along a transverse direction perpendicular to the longitudinal and thickness directions and a second connecting fin extending from the upper end of the second body along the transverse direction,

[0022] - the formation of a lower connecting portion linking the lower ends of the two bodies,

[0023] - the overlap of the end portion of the first connecting fin and the end portion of the second connecting fin along the thickness direction so that the first and second connecting fins form an upper connecting portion linking the upper ends of the two bodies.

[0024] The invention also relates to a method for manufacturing a fibrous assembly of a part comprising:

[0025] - the production of a fibrous core assembly according to the process described above,

[0026] - the production of a fibrous belt assembly,

[0027] - the assembly of the fibrous belt assembly with the fibrous core assembly, the fibrous belt assembly surrounding the fibrous core assembly so as to provide at least one first orifice adjacent to the first body along the longitudinal direction and a second orifice adjacent to the second body along the longitudinal direction, the fibrous belt assembly surrounding the orifices, the first and second orifices being coaxial.

[0028] Finally, the invention relates to a method for manufacturing a mechanical part made of composite material comprising:

[0029] - the manufacture of a fibrous assembly of parts according to the process described previously,

[0030] - the densification of the fibrous assembly of the part by a matrix while preserving the orifices devoid of matrix so as to obtain a mechanical part in composite material, the fibrous core assembly densified by the matrix forming a core and the fibrous belt assembly densified by the matrix forming one or more belts surrounding the core and the coaxial orifices so as to form at least a double cap. Brief description of the drawings

[0031] [Fig.1] Fig.1 is a schematic view of a landing gear.

[0032] [Fig.2] The [Fig.2] is a schematic view of a strut of the landing gear of the [Fig. 1].

[0033] [Fig.3] The [Fig.3] is a schematic perspective view of a first fibrous preform of core according to a first embodiment of a fibrous core assembly.

[0034] [Fig.4] The [Fig.4] is a schematic perspective view of a second fibrous core preform according to the first embodiment of a fibrous core assembly.

[0035] [Fig.5] The [Fig.5] is a schematic top view of the core fiber assembly according to the first embodiment.

[0036] [Fig.6] The [Fig.6] is a schematic cross-sectional view of the core fibrous assembly of the [Fig.5].

[0037] [Fig.7] The [Fig.7] is a schematic cross-sectional view of the core fibrous assembly of the [Fig.5].

[0038] [Fig.8] The [Fig.8] is a schematic cross-sectional view of a fibrous core assembly according to a second embodiment.

[0039] [Fig.9] The [Fig.9] is a schematic cross-sectional view of a fibrous blank allowing the fibrous core assembly of the [Fig.8] to be obtained.

[0040] [Fig. 10] The [Fig. 10] is a schematic perspective view of a fibrous assembly of a part comprising a fibrous belt assembly according to a first embodiment.

[0041] [Fig. 11] The [Fig. 11] is a schematic cross-sectional view of the fibrous assembly of part of the [Fig. 10].

[0042] [Fig. 12] The [Fig. 12] is a schematic perspective view of a fibrous assembly of a part comprising a fibrous belt assembly according to a second embodiment.

[0043] [Fig. 13] The [Fig. 13] is a schematic cross-sectional view of the fibrous assembly of part of the [Fig. 12].

[0044] [Fig. 14] The [Fig. 14] is a schematic perspective view of a mechanical part. Description of the implementation methods

[0045] The present invention relates to a core fiber assembly intended to be densified by a matrix. The core fiber assembly is intended to form the fibrous reinforcement of a core of a mechanical part made of composite material comprising a double clevis.

[0046] According to a first embodiment of the core fiber assembly illustrated in Figures 3 to 6, the core fiber assembly 100 is formed by a first core fiber preform 101 and by a second core fiber preform 102. The core fiber assembly 100 comprises only the two core fiber preforms 101 and 102.

[0047] Figures 3 and 4 illustrate respectively the first and second fibrous core preforms 101 and 102.

[0048] The first fibrous core preform 101 comprises a first body 110, as illustrated in [Fig. 3]. The first body 110 extends lengthwise along a longitudinal direction DL between a first edge and a second edge. At least the first edge has a circular shape. The first body 110 also extends along a thickness direction DE between an upper end 110a and a lower end 110b. The thickness direction DE is perpendicular to the longitudinal direction DL.

[0049] The first fiber core preform 101 further comprises a first connecting fin 111 extending from the upper end 110a of the first body 110 in a transverse direction DT. The transverse direction DT is perpendicular to the longitudinal direction DL and to the thickness direction DE. The first fiber core preform 101 further comprises a third connecting fin 113 extending from the lower end 110b of the first body 110 in the transverse direction DT. The third connecting fin 113 extends in the same direction as the first connecting fin 111. Thus, the first connecting fin 111 and the third connecting fin 113 overlap in the thickness direction DE.

[0050] The first connecting fin 111 comprises a proximal portion and an end portion 111e along the transverse direction DT. The proximal portion of the first connecting fin 111 connects the end portion 11le of said first connecting fin 111 to the first body 110. The proximal portion of the first connecting fin 111 may have a constant thickness along the thickness direction DE. The thickness of the end portion 111e along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the end portion 111e has a thickness along the thickness direction DE that gradually decreases along the transverse direction DT to the end of the connecting fin 111. The end portion 11le of the first connecting fin 111 then has a beveled shape.Such a shape allows for a more gradual transmission of forces between the first fibrous preform 101 and the second fibrous preform 102.

[0051] The first connecting fin 111 may have a constant width along the transverse direction DT along the longitudinal direction DL. The first connecting fin 111 may include a central portion 111c extending along the longitudinal direction DL. The first connecting fin 111 may include transition portions 11 It at the longitudinal ends of said first connecting fin 111 along the longitudinal direction DL. The portions of Transitions 11 and 11 are present on either side of the central portion 111c along the longitudinal direction DL. The width along the transverse direction DT of the transition portion 11 and 11 of the first connecting fin 111 increases progressively from the longitudinal end of the first connecting fin 111 to the central portion 11 and 11. The width of the central portion 111c along the transverse direction DT may be constant along the longitudinal direction DL. Conversely, the width of the central portion 111c along the transverse direction DT may be variable along the longitudinal direction DL. In particular, the width of the central portion 111c along the transverse direction DT may increase progressively along the longitudinal direction DL, as illustrated in [Fig. 3].

[0052] The third connecting fin 113 comprises a proximal portion and an end portion 113e along the transverse direction DT. The proximal portion of the third connecting fin 113 connects the end portion 113e of said third connecting fin 113 to the first body 110. The proximal portion of the third connecting fin 113 may have a constant thickness along the thickness direction DE. The thickness of the end portion 113e along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the end portion 113e has a thickness along the thickness direction DE that gradually decreases along the transverse direction DT to the end of the connecting fin 113. The end portion 113e of the third connecting fin 113 then has a beveled shape.Such a shape allows for a more gradual transmission of forces between the first fibrous preform 101 and the second fibrous preform 102.

[0053] The third connecting fin 113 may have a constant width along the transverse direction DT along the longitudinal direction DL. The third connecting fin 113 may include a central portion 113c extending along the longitudinal direction DL. The third connecting fin 113 may include transition portions 113t at the longitudinal ends of said third connecting fin 113 along the longitudinal direction DL. The transition portions 113t are present on either side of the central portion 113c along the longitudinal direction DL. The width along the transverse direction DT of the transition portion 113t of the third connecting fin 113 increases progressively from the longitudinal end of the third connecting fin 113 to the central portion 113c.The width of the central portion 113c along the transverse direction Dt may be constant along the longitudinal direction DL. Conversely, the width of the central portion 113c along the transverse direction DT may be variable along the longitudinal direction DL. In particular, the width of the central portion. 113c following the transverse direction DT can gradually increase along the longitudinal direction DL, as illustrated in [Fig.3].

[0054] The first fibrous core preform 101 may further include a second external fin 112 extending from the upper end 110a of the first body 110 along the transverse direction DT. The second external fin 112 extends beyond the first body 110. The second external fin 112 extends opposite the first connecting fin 111. The first fibrous core preform 101 may further include a fourth external fin 114 extending from the lower end 110b of the first body 110 along the transverse direction DT. The fourth outer fin 114 extends beyond the first body 110. The fourth outer fin 114 extends opposite the third connecting fin 113. The fourth outer fin 114 extends in the same direction as the second outer fin 112. Thus, the second outer fin 112 and the fourth connecting fin 114 overlap along the thickness direction DE.Thus, the fibrous core preform 101 has an "I" shaped cross-section. If the fibrous core preform 101 does not include external fins, it has a "C" shaped cross-section.

[0055] The second fibrous core preform 102 comprises a second body 120, as illustrated in [Fig. 4]. The second body 120 extends lengthwise along the longitudinal direction DL between a first edge and a second edge. At least the first edge has a circular shape. The second body 120 also extends along the thickness direction DE between an upper end 120a and a lower end 120b.

[0056] The second core fiber preform 102 further comprises a second connecting fin 122 extending from the upper end 120a of the second body 120 along the transverse direction DT. The second core fiber preform 102 further comprises a fourth connecting fin 124 extending from the lower end 120b of the second body 120 along the transverse direction DT. The fourth connecting fin 124 extends in the same direction as the second connecting fin 122. Thus, the second connecting fin 122 and the fourth connecting fin 124 overlap along the thickness direction DE.

[0057] The second connecting fin 122 comprises a proximal portion and an end portion 122e along the transverse direction DT. The proximal portion of the second connecting fin 122 connects the end portion 122e of said second connecting fin 122 to the second body 120. The proximal portion of the second connecting fin 122 may have a constant thickness along the thickness direction DE. The thickness of the end portion 122e along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the The end portion 122e has a thickness along the thickness direction DE that gradually decreases along the transverse direction DT until it reaches the end of the connecting fin 122. The end portion 122e of the second connecting fin 122 then has a beveled shape. This shape allows for a more gradual transmission of forces between the first fibrous preform 101 and the second fibrous preform 102.

[0058] The second connecting fin 122 may have a constant width along the transverse direction DT along the longitudinal direction DL. The second connecting fin 122 may include a central portion 122c extending along the longitudinal direction DL. The second connecting fin 122 may include transition portions 122t at the longitudinal ends of said second connecting fin 122 along the longitudinal direction DL. The transition portions 122t are present on either side of the central portion 122c along the longitudinal direction DL. The width along the transverse direction DT of the transition portion 122t of the second connecting fin 122 increases progressively from the longitudinal end of the second connecting fin 122 to the central portion 122c.The width of the central portion 122c along the transverse direction Dt can be constant along the longitudinal direction DL. In this case, the first body 110 and the second body 120 are parallel in the core fiber assembly 100. Conversely, the width of the central portion 122c along the transverse direction Dt can be variable along the longitudinal direction DL. In this case, the first body 110 and the second body 120 are not parallel in the core fiber assembly 100. In particular, the width of the central portion 122c along the transverse direction DT can gradually increase along the longitudinal direction Dl, as illustrated in [Fig. 4].

[0059] The fourth connecting fin 124 comprises a proximal portion and an end portion 124e along the transverse direction DT. The proximal portion of the fourth connecting fin 124 connects the end portion 124e of said fourth connecting fin 124 to the second body 120. The proximal portion of the fourth connecting fin 124 may have a constant thickness along the thickness direction DE. The thickness of the end portion 124e along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the end portion 124e has a thickness along the thickness direction DE that gradually decreases along the transverse direction DT to the end of the connecting fin 124. The end portion 124e of the fourth connecting fin 124 then has a beveled shape. Such a shape allows for transmission more progressive efforts between the first fibrous preform 101 and the second fibrous preform 102.

[0060] The fourth connecting fin 124 may have a constant width along the transverse direction DT along the longitudinal direction DL. The fourth connecting fin 124 may include a central portion 124c extending along the longitudinal direction DL. The fourth connecting fin 124 may include transition portions 124t at the longitudinal ends of said fourth connecting fin 124 along the longitudinal direction DL. The transition portions 124t are present on either side of the central portion 124c along the longitudinal direction DL. The width along the transverse direction DT of the transition portion 124t of the fourth connecting fin 124 increases progressively from the longitudinal end of the fourth connecting fin 124 to the central portion 124c.The width of the central portion 124c along the transverse direction Dt can be constant along the longitudinal direction DL. In this case, the first body 110 and the second body 120 are parallel in the core fiber assembly 100. Conversely, the width of the central portion 124c along the transverse direction Dt can be variable along the longitudinal direction DL. In this case, the first body 110 and the second body 120 are not parallel in the core fiber assembly 100. In particular, the width of the central portion 124c along the transverse direction DT can gradually increase along the longitudinal direction Dl, as illustrated in [Fig. 4].

[0061] The second fibrous core preform 102 may further include a first external fin 121 extending from the upper end 120a of the second body 120 along the transverse direction DT. The first external fin 121 extends beyond the second body 120. The first external fin 121 extends opposite the second connecting fin 122. The second fibrous core preform 102 may further include a third external fin 123 extending from the lower end 120b of the second body 120 along the transverse direction DT. The third outer fin 123 extends beyond the second body 120. The third outer fin 123 extends opposite the fourth connecting fin 124. The third outer fin 123 extends in the same direction as the first outer fin 121. Thus, the first outer fin 121 and the third connecting fin 123 overlap along the thickness direction DE.Thus, the fibrous core preform 102 has an "I" shaped cross-section. If the fibrous core preform 102 does not include external fins, it has a "C" shaped cross-section.

[0062] The presence of external fins helps to limit the risk of buckling of the part.

[0063] The core fiber preforms 101 and 102 are produced by weaving. Preferably, the core fiber preforms 101 and 102 are produced by three-dimensional weaving. Each core fiber preform 101, 102 can be produced in a single piece by three-dimensional weaving. By "three-dimensional weaving" is meant a weaving method in which at least some of the warp yarns bind weft yarns over several weft layers. A reversal of roles between warp and weft is possible. The core fiber preforms 101 and 102 can be produced in a well-known manner using a Jacquard-type loom. Preferably, the core fiber preforms 101 and 102 are formed from carbon fibers. The core fiber preforms 101 and 102 preferably have an interlock weave.Interlock weaving refers to a three-dimensional weave structure in which each warp layer connects multiple weft layers, with all yarns in the same warp column having the same movement within the plane of the weave.

[0064] The fibrous core preforms 101 and 102 are assembled to obtain the fibrous core assembly 100, as illustrated in the top view in [Fig. 5] and in cross-section in Figures 6 and 7. In the example shown here, the bodies 110 and 120 are not parallel. Of course, this does not depart from the scope of the first embodiment if the bodies 110 and 120 are parallel.

[0065] The core fiber preforms 101 and 102 are assembled such that the first connecting fin 111 and the second connecting fin 122 overlap along the thickness direction DE and such that the third connecting fin 113 and the fourth connecting fin 124 overlap along the thickness direction DE. In particular, the core fiber preforms 101 and 102 are assembled such that the end portion 111e of the first connecting fin 111 and the end portion 122e of the second connecting fin 122 overlap along the thickness direction DE and such that the end portion 113e of the third connecting fin 113 and the end portion 124e of the fourth connecting fin 124 overlap along the thickness direction DE.The first connecting fin 111 and the second connecting fin 122 overlap to form an upper connecting portion 100a linking the upper ends 110a and 120a of the first and second bodies 110 and 120. The third connecting fin 113 and the fourth connecting fin 124 overlap to form a lower connecting portion 100b linking the lower ends 110b and 120b of the first and second bodies 110 and 120.

[0066] If it is desired to form an upper connecting portion 100a of constant or quasi-constant cross-section, the end portion 111e of the first connecting fin 111 and the end portion 122e of the second connecting fin 122 must be complementary. Similarly, if we wish to form a lower link portion 100b of constant or quasi-constant cross-section, the end portion 113e of the third link fin 113 and the end portion 124e of the fourth link fin 124 must be complementary.

[0067] Preferably, to simplify the manufacturing process, the first fibrous preform 101 and the second fibrous preform 102 are identical. Thus, in this case, the end portion 122e of the second connecting fin 122 and the end portion 113e of the third connecting fin 113 must be between the end portion 11e of the first connecting fin 111 and the end portion 124e of the fourth connecting fin 124. In this case, the central portions 111c, 113c, 122c and 124c of the connecting fins must have a constant width along the transverse direction DT along the longitudinal direction DL and the bodies 110 and 120 must be parallel.

[0068] According to a second embodiment of the core fiber assembly illustrated in Figures 8 to 9, the core fiber assembly 200 is formed by a single core fiber preform 200.

[0069] The fibrous core preform 200 comprises a first body 210 and a second body 220, as illustrated in cross-section in [Fig. 8]. The first body 210 extends lengthwise along a longitudinal direction DL between a first edge and a second edge. At least the first edge has a circular shape. The first body 210 also extends along a thickness direction DE between an upper end 210a and a lower end 210b. The thickness direction DE is perpendicular to the longitudinal direction DL. The second body 220 extends lengthwise along the longitudinal direction DL between a first edge and a second edge. At least the first edge has a circular shape. The second body 220 also extends along the thickness direction DE between an upper end 220a and a lower end 220b.

[0070] The fibrous core preform 200 further comprises a first connecting fin 211 extending from the upper end 210a of the first body 210 in a transverse direction DT. The transverse direction DT is perpendicular to the longitudinal direction DL and to the thickness direction DE. The first connecting fin 211 comprises a proximal portion and an end portion 211 along the transverse direction DT. The proximal portion of the first connecting fin 211 connects the end portion 211 of said first connecting fin 211 to the first body 210. The proximal portion of the first connecting fin 211 may have a constant thickness along the thickness direction DE. The thickness of the end portion 211 along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the end portion 21 has a thickness along the thickness direction DE which gradually decreases along the transverse direction DT up to the end of the connecting fin 211. The end portion 21 of the first connecting fin 211 then has a beveled shape.

[0071] The first connecting fin 211 may have a constant width along the transverse direction DT along the longitudinal direction DL. The first connecting fin 211 may include a central portion extending along the longitudinal direction DL. The first connecting fin 211 may include transition portions at the longitudinal ends of said first connecting fin 211 along the longitudinal direction DL. The transition portions are present on either side of the central portion along the longitudinal direction DL. The width along the transverse direction DT of the transition portion of the first connecting fin 211 increases progressively from the longitudinal end of the first connecting fin 211 to the central portion.In this second embodiment of the invention, the width of the central portion along the transverse direction DT is constant along the longitudinal direction DL. Thus, the first body 210 and the second body 220 are parallel.

[0072] The fibrous core preform 200 further comprises a second connecting fin 222 extending from the upper end 220a of the second body 220 along the transverse direction DT. The second connecting fin 222 comprises a proximal portion and an end portion 222e along the transverse direction DT. The proximal portion of the second connecting fin 222 connects the end portion 222e of said second connecting fin 222 to the second body 220. The proximal portion of the second connecting fin 222 may have a constant thickness along the thickness direction DE. The thickness of the end portion 222e along the thickness direction DE is less than the thickness of the proximal portion. Preferably, the end portion 222e has a thickness along the thickness direction DE which gradually decreases along the transverse direction DT up to the end of the connecting fin 222.The end portion 222e of the second connecting fin 222 then has a beveled shape. Such a shape allows a more gradual transmission of forces between the first connecting fin 211 and the second connecting fin 222.

[0073] The second connecting fin 222 may have a constant width along the transverse direction DT along the longitudinal direction DL. The second connecting fin 222 may include a central portion extending along the longitudinal direction DL. The second connecting fin 222 may include transition portions at the longitudinal ends of said second connecting fin. 222 along the longitudinal direction DL. Transition portions are present on either side of the central portion along the longitudinal direction DL. The width along the transverse direction DT of the transition portion of the second connecting fin 222 increases progressively from the longitudinal end of the first connecting fin 222 to the central portion. In this second embodiment of the invention, the width of the central portion along the transverse direction DT is constant along the longitudinal direction DL. Thus, the first body 210 and the second body 220 are parallel.

[0074] The fibrous core preform includes a lower bonding portion 200b connecting the lower end 210b of the first body 210 and the lower end 220b of the second body 220. The lower bonding portion 200b extends along the transverse direction DT.

[0075] The core fiber preform 200 may further include a first external fin 221 extending from the upper end 220a of the second body 220 along the transverse direction DT. The first external fin 221 extends beyond the second body 220. The first external fin 221 extends opposite the second connecting fin 222. The core fiber preform 200 may further include a second external fin 212 extending from the upper end 210a of the first body 210 along the transverse direction DT. The second outer fin 212 extends beyond the first body 210. The second outer fin 212 extends opposite the first connecting fin 211. The fibrous core preform 200 may further include a third outer fin 223 extending from the lower end 220b of the second body 220 along the transverse direction DT. The third outer fin 223 extends beyond the second body 220.The third outer fin 223 extends opposite the lower connecting portion 200b. The third outer fin 223 extends in the same direction as the first outer fin 221. Thus, the first outer fin 221 and the third connecting fin 223 overlap along the thickness direction DE. The fibrous core preform 200 may further include a fourth outer fin 214 extending from the lower end 210b of the first body 210 along the transverse direction DT. The fourth outer fin 214 extends beyond the first body 210. The fourth outer fin 214 extends opposite the lower connecting portion 200b. The fourth outer fin 214 extends in the same direction as the second outer fin 212. Thus, the second outer fin 212 and the fourth connecting fin 214 overlap along the thickness direction DE.

[0076] The core fiber preform 200 can be produced by weaving. Preferably, the core fiber preform 200 is produced by three-dimensional weaving. The preform The 200 core fiber preform can be produced in a single piece by three-dimensional weaving. The 200 core fiber preform can be produced in a well-known manner using a Jacquard-type loom. Preferably, the 200 core fiber preform is made of carbon fibers. The 200 core fiber preform preferably has an interlock weave.

[0077] The first connecting fin 211 and the second connecting fin 222 overlap along the thickness direction DE. In particular, the end portion 21le of the first connecting fin 211 and the end portion 222e of the second connecting fin 222 overlap along the thickness direction DE. The first connecting fin 211 and the second connecting fin 222 overlap so as to form an upper connecting portion 200a linking the upper ends 210a and 220a of the first and second bodies 210 and 220. If it is desired to form an upper connecting portion 200a of constant or nearly constant cross-section, the end portion 21le of the first connecting fin 211 and the end portion 222e of the second connecting fin 222 must be complementary.

[0078] Figure 9 illustrates in cross-section an example of a fibrous blank 700 exiting the loom. weaving, intended to be shaped to obtain the 200 core fibrous preform.

[0079] The fiber blank 700 comprises a first body 710 and a second body 720 extending lengthwise along the longitudinal direction DL. The first body 710 of the fiber blank 700 is intended to form the first body 210 of the core fiber preform 200. The second body 720 of the fiber blank 700 is intended to form the second body 220 of the core fiber preform 200. The first body 710 and the second body 720 of the fiber blank 700 extend parallel to each other.

[0080] The first body 710 of the fibrous blank 700 extends along the transverse direction DT between an upper end 710a and a lower end 710b. The second body 720 of the fibrous blank 700 extends along the transverse direction DT between an upper end 720a and a lower end 720b. The upper ends 710a, 720a of the bodies 710, 720 of the fibrous blank 700 are intended to form the upper ends 210a, 220a of the bodies 210, 220 of the fibrous preform 200. The lower ends 710b, 720b of the bodies 710, 720 of the fibrous blank 700 are intended to form the lower ends 210b, 220b of the bodies 210, 220 of the fibrous preform 200.

[0081] The first body 710 of the fibrous blank 700 extends along the thickness direction DE between a first side 710c and a second side 710d. The second body 720 of the fibrous blank 700 extends along the thickness direction DE between a first side 720c and a second side 720d.

[0082] The fibrous blank 700 includes a lower connecting portion 700b linking the lower ends 710b, 720b of the first body 710 and the second body 720 at the level of the first sides 710c, 720c of said bodies 710 and 720. The lower connecting portion 700b extends along the transverse direction DT.

[0083] The fiber blank 700 includes a first connecting fin 711 extending from the upper end 710a of the first body 710 along the transverse direction DT. The first connecting fin 711 extends from the first side 710c of the first body 710. The first connecting fin 711 extends opposite the lower connecting portion 700b. The first connecting fin 711 of the blank 700 is intended to form the first connecting fin 211 of the core fiber preform 200.

[0084] The fiber blank 700 includes a second connecting fin 722 extending from the upper end 720a of the second body 720 in the transverse direction DT. The second connecting fin 722 extends from the first side 720c of the second body 720. The second connecting fin 722 extends opposite the lower connecting portion 700b. The second connecting fin 722 of the blank 700 is intended to form the second connecting fin 222 of the core fiber preform 200.

[0085] The fiber blank 700 includes a first outer fin 721 extending from the upper end 720a of the second body 720 along the transverse direction DT. The first outer fin 721 extends from the second side 720d of the second body 720. The first outer fin 721 of the blank 700 is intended to form the first outer fin 221 of the core fiber preform 200.

[0086] The fibrous blank 700 includes a second outer fin 712 extending from the upper end 710a of the first body 710 along the transverse direction DT. The second outer fin 712 extends from the second side 710d of the first body 710. The second outer fin 712 of the blank 700 is intended to form the second outer fin 212 of the fibrous core preform 200.

[0087] The fiber blank 700 includes a third external fin 723 extending from the lower end 720b of the second body 720 along the transverse direction DT. The third external fin 723 extends from the second side 720d of the second body 720. The third external fin 723 extends opposite the first external fin 721. The third external fin 723 of the blank 700 is intended to form the third external fin 223 of the core fiber preform 200.

[0088] The fibrous blank 700 includes a fourth external fin 714 extending from the lower end 710b of the first body 710 along the transverse direction DT. The fourth external fin 714 extends from the second side 710d of the first body 120. The fourth outer fin 714 extends opposite the second outer fin 712. The fourth outer fin 714 of the blank 700 is intended to form the fourth outer fin 214 of the fibrous core preform 200.

[0089] The fiber blank 700 is then folded to obtain the fiber core preform 200. In particular, the fiber blank 700 is folded so that the bodies 710 and 720 extend between their upper end 710a, 720a and their lower end 710b, 720b along the thickness direction DE and no longer along the transverse direction DT. The connecting fins 711, 722 are folded relative to the bodies 710, 720 so as to overlap. All the external fins 721, 712, 723, 714 are folded relative to the bodies.

[0090] The resulting core fiber assembly 100 or 200 is then assembled with a belt fiber assembly to form a part fiber assembly.

[0091] According to a first embodiment of the fibrous assembly of the part illustrated in Figures 10 and 11, the fibrous belt assembly is formed by a single fibrous belt preform 300.

[0092] The assembly of the core fiber assembly 100 or 200 with the belt fiber assembly 300 to obtain the part fiber assembly 1000 is carried out such that the belt fiber preform 300 surrounds the core fiber assembly 100 or 200. The belt fiber preform 300 defines at least two openings 330a, 330b. The first opening 330a is adjacent to the first body 110 or 210 along the longitudinal direction DL. In particular, the first opening 330a may be defined by the first edge of the first body 110 or 210. The second opening 330b is adjacent to the second body 120 or 220 along the longitudinal direction DL. In particular, the second orifice 330b can be delimited by the first edge of the second body 120 or 220. The orifices 330a and 330b extend along the transverse direction DT. The first orifice 330a and the second orifice 330b extend along the same axis. Thus, the first orifice 330a and the second orifice 330b are coaxial.The first orifice 330a and the second orifice 330b of the fibrous assembly of part 1000 are configured to form the two orifices of a double clevis of the mechanical part to be obtained.

[0093] If a mechanical part is to be made comprising a double clevis at each end, the fibrous belt preform 300 further defines a third orifice 330c and a fourth orifice 330d. The third orifice 330c is adjacent to the first body 110 or 210 along the longitudinal direction DL. In particular, the third orifice 330a can be defined by the second edge of the first body 110 or 210. The third orifice 330c is opposite the first orifice 330a along the longitudinal direction DL. The fourth orifice 330d is adjacent to the second body 120 or 220 along the longitudinal direction DL. In particular, the fourth orifice 330d can to be delimited by the second edge of the second body 120 or 220. The orifices 330c and 330d extend along the transverse direction DT. The third orifice 330c and the fourth orifice 330d extend along the same axis. Thus, the third orifice 330c and the fourth orifice 330d are coaxial. The third orifice 330c and the fourth orifice 330d of the fibrous assembly of part 1000 are configured to form the two orifices of another double clevis of the mechanical part to be obtained.

[0094] To facilitate the positioning of the fibrous belt preform 300 around the fibrous core assembly 100 or 300, positioning elements may be used. The positioning elements are arranged against the first and / or second edges of the bodies of the fibrous core assembly 100 or 300. The positioning elements allow the orifice(s) 330a, 330b, 330c, 330d to be defined.

[0095] The fibrous preform of the belt 300 is in contact with the first body 110 or 210 of the fibrous core assembly 100 or 200 and in contact with the second body 120 or 220 of the fibrous core assembly 100 or 200.

[0096] According to a second embodiment of the fibrous assembly of the part illustrated in Figures 12 and 13, the fibrous belt assembly is formed by a first fibrous belt preform 401 and by a second fibrous belt preform 402. The fibrous belt assembly 400 comprises only the two fibrous belt preforms 401 and 402.

[0097] The assembly of the core fiber assembly 100 or 200 with the belt fiber assembly 400 to obtain the part fiber assembly 2000 is carried out such that the belt fiber preforms 401, 402 surround the core fiber assembly 100 or 200. In particular, the first belt fiber preform 401 surrounds the first body 110 or 210 of the core fiber assembly 100 or 200. The first belt fiber preform 401 may be in contact with the first body 110 or 210 of the core fiber assembly 100 or 200. The second belt fiber preform 402 surrounds the second body 120 or 220 of the core fiber assembly 100 or 200. The second belt fiber preform 402 may to be in contact with the second body 120 or 220 of the fibrous core assembly 100 or 200.

[0098] The fibrous belt preforms 401, 402 can be in contact with each other. Conversely, preferably, the first fibrous belt preform 401 can be spaced from the second fibrous belt preform 402 by a non-zero distance along the transverse direction DT. Thus, the fibrous assembly of part 2000 is lighter.

[0099] The first fibrous belt preform 401 defines at least one first orifice 430a. The first orifice 430a is adjacent to the first body 110 or 210 along the longitudinal direction DL. In particular, the first orifice 430a may be defined by the first edge of the first body 110 or 210. The second fibrous preform The belt 402 defines at least one second orifice 430b. The second orifice 430b is adjacent to the second body 120 or 220 along the longitudinal direction D1. In particular, the second orifice 430b may be defined by the first edge of the second body 120 or 220. The orifices 430a and 430b extend along the transverse direction DT. The first orifice 430a and the second orifice 430b extend along the same axis. Thus, the first orifice 430a and the second orifice 430b are coaxial. The first orifice 430a and the second orifice 430b of the fibrous assembly of part 2000 are configured to form the two orifices of a double clevis of the mechanical part to be obtained.

[0100] If a mechanical part is to be made comprising a double clevis at each end, the fibrous belt preforms 401, 402 further define a third orifice 430c and a fourth orifice 430d. The first fibrous belt preform 401 defines the third orifice 430c. The third orifice 430c is adjacent to the first body 110 or 210 along the longitudinal direction DL. In particular, the third orifice 430a can be defined by the second edge of the first body 110 or 210. The third orifice 430c is opposite the first orifice 430a along the longitudinal direction DL. The second fibrous belt preform 402 defines the fourth orifice 430d. The fourth orifice 430d is adjacent to the second body 120 or 220 along the longitudinal direction DL. In particular, the fourth orifice 430d can be delimited by the second edge of the second body 120 or 220. The orifices 430c, 430d extend along the transverse direction DT.The third orifice 430c and the fourth orifice 430d extend along the same axis. Thus, the third orifice 430c and the fourth orifice 430d are coaxial. The third orifice 430c and the fourth orifice 430d of the fibrous assembly of part 2000 are configured to form the two orifices of another double clevis of the mechanical part to be obtained.

[0101] To facilitate the positioning of the fibrous belt preforms 401, 402 around the core fiber assembly 100 or 300, positioning elements may be used. The positioning elements are arranged against the first and / or second edges of the bodies of the core fiber assembly 100 or 300. The positioning elements allow the orifice(s) 430a, 430b, 430c, 430d to be defined.

[0102] The fibrous belt preform(s) 300, 401, 402 can be produced by three-dimensional weaving. The fibrous belt preform(s) 300, 401, 402 can be produced in a well-known manner using a Jacquard-type loom. Preferably, the fibrous belt preform(s) 300, 401, 402 are formed from carbon fibers. The fibrous belt preform(s) 300, 401, 402 preferably have an interlock weave. The same type of fibers and Fibers of the same material can be used for the core fiber assembly of 100 or 200 and the belt fiber assembly of 300 or 400.

[0103] The resulting fibrous assembly can be used to form the fibrous reinforcement of a connecting rod or lever having at least one double clevis. The fibrous assembly can be used to form the fibrous reinforcement of a mechanical part for aeronautical equipment intended for flight. For example, the fibrous assembly according to the invention can be used to form the fibrous reinforcement of a connecting rod or landing gear lever having at least one double clevis.

[0104] The resulting fiber assembly of part 1000 or 2000 is then densified by a matrix. The core fiber assembly 100 or 200 and the belt fiber assembly 300 or 400 are thus co-densified. Preferably, the mechanical part is made of an organic matrix composite material, known as an "OMC". For this purpose, the fiber assembly of part 1000 or 2000 can be placed in a mold. Densification by the matrix can be achieved by introducing a resin into the fiber assembly of part 1000 or 2000, such as an epoxy resin. The introduction of the resin is followed by cross-linking if it is a thermosetting resin or by cooling if it is a thermoplastic resin. The matrix formation can be achieved by resin transfer molding technique (“Resin Transfer Molding”), which is a well-known technique in itself.The positioning elements described above can be retained during densification, in order to prevent the matrix material from filling the orifice(s).

[0105] This gives us a mechanical part 10 made of composite material, as illustrated in [Fig. 14], whose fibrous reinforcement is formed by the fibrous assembly of part 1000 or 2000.

[0106] The mechanical part 10 comprises a core 11 whose fibrous reinforcement is formed by the core fiber assembly 100 or 200. The mechanical part 10 comprises one or two belts 12 whose fibrous reinforcement is formed by the belt fiber assembly 300 or 400. The mechanical part 10 comprises at least two coaxial openings 13a, 13b adjacent to the core 11. The openings 13a, 13b are intended to be traversed by a shaft to create a connection with another part. The openings 13a, 13b form a double yoke. The belt(s) 12 surround the core 11 and the opening(s) 13a, 13b. The mechanical part 10 may include two other coaxial openings 13c, 13d adjacent to the web 11. The openings 13c, 13d are intended to be traversed by another shaft to create a connection with another part. The openings 13c, 13d form another double yoke. The belt(s) 12 surround the web 11 and the opening(s) 13c, 13d.

[0107] The mechanical part 10 may include one or more rings. The ring(s) may be added to the holes 13a, 13b, 13c, 13d. It is, of course, within the scope of the invention if the rings are attached to the fibrous assembly of the part. 1000 before densification by the matrix. At least one ring can be placed in each orifice 13a, 13b, 13c, 13d. The outer surface of the ring can correspond to the inner surface of the orifice 13a, 13b, 13c, 13d. The core 11 can conform to the shape of the ring(s). The belt(s) 12 can conform to the shape of the ring(s). The ring(s) can be made of metal. The ring(s) can also be made of composite material.

[0108] The part according to the invention may or may not be intended for an aeronautical application. The part may, for example, be a connecting rod, a landing gear strut or a component thereof, or a brake rod, which includes at least one double clevis.

Claims

Demands

1. A core fiber assembly (100) intended to form the fiber reinforcement of a core (11) of a part (10) made of composite material comprising a first body (110) and a second body (120) extending lengthwise along a longitudinal direction (DL) and each extending along a thickness direction (DE) perpendicular to the longitudinal direction (DL) between an upper end (110a, 120a) and a lower end (110b, 120b), the core fiber assembly (100) being characterized in that it further comprises at least one first connecting fin (111) extending from the upper end (110a) of the first body (110) along a transverse direction (DT) perpendicular to the longitudinal (DL) and thickness (DE) directions and a second connecting fin (122) extending from the upper end (120a) of the second body (120) along the transverse direction (DT),the end portion (111e) of the first connecting fin (111) and the end portion (122e) of the second connecting fin (122) overlap along the thickness direction (DE) such that the first and second connecting fins (111, 122) form an upper connecting portion (100a) linking the upper ends (110a, 120a) of the two bodies (110, 120), the core fiber assembly (100) further comprising a lower connecting portion (100b) linking the lower ends (110b, 120b) of the two bodies (110, 120).

2. Core fiber assembly (100) according to claim 1, the core fiber assembly (100) further comprising a plurality of external fins (121, 112, 123, 114) extending from the upper (110a, 120a) or lower (110b, 120b) end of the bodies (110, 120) in the transverse direction (DT) opposite the connecting portions (100a, 100b).

3. Core fiber assembly (100) according to claim 1 or 2, the core fiber assembly (100) further comprising at least one third connecting fin (113) extending from the lower end (110b) of the first body (110) in the transverse direction (DT) and a fourth connecting fin (124) extending from the lower end (120b) of the second body (120) in the transverse direction (DT), the end portion (113e) of the third connecting fin (113) and the end portion (124e) of the fourth connecting fin (124) overlap along the thickness direction (DE) so that the third and fourth connecting fins (113, 124) form the lower connecting portion (100b).

4. Core fibrous assembly (100) according to claim 3, wherein the first body (110) and the fin(s) (111, 112, 113, 114) extending from the upper and lower ends (110a, 110b) of said first body (110) belong to the same first fibrous preform (101) and wherein the second body (120) and the fin(s) (121, 122, 123, 124) extending from the upper and lower ends (120a, 120b) of said second body (120) belong to the same second fibrous preform (102).

5. Core fiber assembly (200) according to claim 1 or 2, the core fiber assembly (200) being formed by a single one-piece fibrous preform (200).

6. Core fiber assembly (100) according to any one of claims 1 to 5, wherein the thickness along the thickness direction (DE) of the end portions (111e, 122e, 113e, 124e) of the connecting fins (111, 122, 113, 124) gradually decreases along the transverse direction (DT) to the end of said connecting fins.

7. Part fiber assembly (1000; 2000) comprising a core fiber assembly (100, 200) according to any one of claims 1 to 6 and a belt fiber assembly (300, 400), the belt fiber assembly (300, 400) surrounding the core fiber assembly (100, 200) so as to provide at least a first orifice (330a, 430a) adjacent to the first body (110) along the longitudinal direction (DL) and a second orifice (330b, 430b) adjacent to the second body (120) along the longitudinal direction (DL), the belt fiber assembly (300, 400) surrounding the orifices, the first and second orifices being coaxial.

8. Mechanical part (10) made of composite material, the fibrous reinforcement of which is formed by the part fiber assembly (1000; 2000) according to claim 7 densified by a matrix, the core fiber assembly (100; 200) densified by the matrix forming a core (11), and the belt fiber assembly (300; 400) densified by the matrix forming one or more belts (12) surrounding the core (11) and the coaxial ports (13a, 13b, 13c, 13d) so as to form at least a double cap.

9. A method for manufacturing a fibrous core assembly (100; 200) intended to form the fibrous reinforcement of a core (11) of a part (10) made of composite material, comprising: - the creation by weaving of a first body (110) and a second body (120) extending lengthwise along a longitudinal direction (DL) and each extending along a thickness direction (DE) perpendicular to the longitudinal direction (DL) between an upper end (110a, 120a) and a lower end (110b, 120b), of at least one first connecting fin (111) extending from the upper end (110a) of the first body (110) along a transverse direction (DT) perpendicular to the longitudinal (DL) and thickness (DE) directions, and a second connecting fin (122) extending from the upper end (120a) of the second body (120) along the transverse direction (DT),- the formation of a lower connecting portion (100b) linking the lower ends (110b, 120b) of the two bodies (110, 120), - the overlapping of the end portion (11e) of the first connecting fin (111) and the end portion (122e) of the second connecting fin (122) along the thickness direction (De) so that the first and second connecting fins (111, 122) form an upper connecting portion (100a) linking the upper ends (110a, 120a) of the two bodies (110, 120).

10. A method for manufacturing a fibrous assembly of a part (1000; 2000) comprising: - producing a core fiber assembly (100, 200) according to claim 9, - producing a belt fiber assembly (300, 400), - assembling the belt fiber assembly (300, 400) with the core fiber assembly (100, 200), the belt fiber assembly (300, 400) surrounding the core fiber assembly (100, 200) so as to provide at least one first opening (330a, 430a) adjacent to the first body (110) along the longitudinal direction (DL) and a second opening (330b, 430b) adjacent to the second body (120) along the longitudinal direction (DL), the belt fiber assembly (300, 400) surrounding the orifices, the first and second orifices being coaxial.

11. A method for manufacturing a mechanical part (10) made of composite material comprising: - manufacturing a fibrous part assembly (1000; 2000) according to claim 10, - densifying the fibrous part assembly (1000; 2000) by a matrix while retaining the orifices devoid of matrix so as to obtain a mechanical part (10) made of composite material, the fibrous core assembly (100, 200) densified by the matrix forming a core (11) and the fibrous belt assembly (300, 400) densified by the matrix forming one or more belts (12) surrounding the core (11) and the coaxial orifices (13a, 13b, 13c, 13d) so as to form at least a double cap.

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