Method of manufacturing a composite part, and resulting part

Abstract

The invention relates to a method for manufacturing a composite part intended for being subjected, via at least one attachment point, to pulling and/or compression forces. The method includes: winding fibers on a hub so as to form a portion of the wall of the part, and creating an externally convex rounded area at the location intended to form the area for applying the pulling and/or compression forces. The forces are radial thereto. The method also includes placing an insert on the convex rounded area, the insert including the attachment point or a mechanism for rigidly connecting the attachment point, and continuing to wind fibers so as to form the rest of the wall, while covering a portion of the insert and leaving the attachment point or the mechanism for rigidly connecting the attachment point accessible.

Claims

1. A method for manufacturing a composite part, the method comprising the steps of: forming a wall by winding fibers on a hub so as to form a wall in a set direction; forming a first end portion by winding said fibers on an end of said hub, said first end portion having a first externally convex rounded area comprised of a first outer surface, a first inner surface, and a first attachment end surface orthogonal to said set direction, wherein a first group of said fibers are wound in a orthogonal direction to said set direction along said first attachment end surface to a first height; placing an insert on said first end portion, said insert having an attachment point surface, said first attachment end surface being aligned with said attachment point so as to form a continuous attachment surface; forming a second end portion by winding said fibers over at least a portion of said insert, said second end portion having a second externally convex rounded area comprised of a second outer surface, a second inner surface, and a second attachment end surface orthogonal to said set direction, wherein a second group of said fibers are wound in a orthogonal direction to said set direction along said second attachment end surface to a second height, and wherein said second attachment end surface aligns with said continuous attachment surface, said continuous attachment surface being comprised of said first attachment surface, said attachment point surface, and said second attachment surface; and embedding said fibers in a matrix.

2. The method for manufacturing a composite part, according to claim 1, said first height corresponding to thickness of said first end portion and an angle of curvature of said first end portion being externally convex.

3. The method for manufacturing a composite part, according to claim 2, said thickness of said first end portion being equal to a thickness of said first attachment end surface.

4. The method for manufacturing a composite part, according to claim 1, said second height corresponding to said first height.

5. The method for manufacturing a composite part, according to claim 4, wherein thickness of said second attachment end surface is equal to said thickness of said first attachment end surface.

6. The method for manufacturing a composite part, according to claim 1, wherein said at least a portion of said insert comprises a concave face joined to said first outer surface of said first end portion and a convex face joined to said second inner surface of said second end portion.

7. The method for manufacturing a composite part, according to claim 6, wherein said concave face has a first constant radius of curvature, wherein said convex face has a second constant radius of curvature, and wherein said first constant radius of curvature is generally identical to said second constant radius of curvature.

8. The method for manufacturing a composite part, according to claim 1, wherein said insert is comprised of another composite material, said another composite material being comprised of insert fibers and an insert matrix, wherein said insert fibers are generally identical to said fibers, and wherein said insert matrix is generally identical to said matrix.

9. The method for manufacturing a composite part, according to claim 8, wherein said insert matrix is a thermoplastic resin, and wherein said matrix is a thermoplastic resin, the method further comprising the step of: fusing said insert with said wall.

10. The method for manufacturing a composite part, according to claim 1, wherein the step of placing said insert on said first end portion comprises the steps of: winding additional fibers in another set direction so as to form said attachment point surface with said additional fibers.

11. The method for manufacturing a composite part, according to claim 10, wherein said another set direction is different from said set direction.

12. The method for manufacturing a composite part, according to claim 10, wherein said another set direction is generally identical to said set direction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 represents a schematic partial cross-sectional view of a composite part achieved by the method according to the invention.

(2) FIGS. 2a and 2b represent schematic partial cross-sectional views of the same composite part.

(3) FIGS. 3a, 3b and 3c represent schematic partial cross-sectional views showing variants of implementation of the method according to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(4) When referring now to FIG. 1, one can see the end 10 of a part 1 made out of composite material manufactured according to the inventive method. This end is aimed at being provided with an attachment point, in order to be capable of subjecting the part 1 to pulling and/or compression forces. The part 1 consists in this case, but not restrictively, of a connecting rod.

(5) The part 1 comprises a tubular wall 11 formed of fibers and resin, and its end 10 includes an insert 2, embedded in the thickness of the wall 11.

(6) The insert 2 includes, on the one hand, a bowl-shaped portion 20, comprising a concave inner face 21, a convex outer face 22 and, on the other hand, an axial shaft 23 aimed at permitting the fixing of securing means.

(7) At the level of the end 10 of the part 1, the tubular wall 11 is divided into two layers, one inner layer 13 and one outer layer 14, between which the insert 2 is inserted.

(8) The inner layer 13, having a first outer surface 13′, a first inner surface 13″, and a first attachment end surface 13′″ orthogonal to a set direction, matches the shape of the concave inner face 21, and the fibers passing through it are parallel to the latter.

(9) Likewise, the outer layer 14, having a second outer surface 14′, a second inner surface 14″, and a second attachment end surface 14′″ orthogonal to a set direction, matches the shape of the convex outer face 22, and the fibers passing through it are parallel to the latter.

(10) Under pulling the force is made between the outer layer 14 and the convex outer face 22, while under compression the force is made between the inner layer 13 and the concave inner face 21.

(11) The part 1 is obtained through the inventive manufacturing method, i.e. fibers are wound so as to form the tubular wall 11 and the end 10, e.g. using a core, in a first time until forming the inner layer 13. Then the insert 2 is placed, the concave inner face 21 of its portion 20 being joined to the inner layer 13, which has a rounded shape at the level of the end 10, then the winding of fibers is continued so as to form the rest of the tubular wall 11 and the outer layer 14, by covering the convex outer face 22 of the portion 20 of the insert 2, while leaving the axial shaft 23 accessible, in order to be able to fix a securing means, not shown.

(12) The insert 2 can be made out of metal, or of a composite material, eventually identical to that, which the tubular wall 11 is made of. In the case of a thermoplastic matrix, it is possible to finally obtain a fusion of the insert 2 and the wall 11.

(13) When referring now to FIGS. 2a and 2b, one can see variants of the invention, in which the insert is created during the manufacturing of the part.

(14) In these figures can be seen the tubular wall 11 and its inner 13 and outer 14 layers, wherein each of which have a rounded shape, while the insert is replaced by an extra quantity 15 of material arranged between these inner 13 and outer 14 layers.

(15) The means for fixing the securing means is filled with a threaded hole 16, obtained by previously and temporarily placing a threaded rod, not shown, and essentially made in the extra quantity 15 of material, as shown in FIG. 2a, or only in the inner layer 13, as shown in FIG. 2b.

(16) As regards the embodiment of FIG. 2b, during the forming of the inner layer 13, one proceeds to winding fibers on the threaded rod of the core, not shown, so as to create, simultaneously with the inner layer 13, a threaded shaft 17, around which the extra quantity 15 of material will be created.

(17) The extra quantity 15 can consist of an excess coiling of fibers, after forming the inner layer 13, by winding in directions different from those in which are wound the fibers for forming the tubular wall 11, for example coaxially to the axis XX′ of the part 11.

(18) The extra quantity 15 cooperates with the fibers of the wall 11, in the same way as the insert 2, it also includes a concave inner face 150 and a convex outer face 151.

(19) When referring to FIGS. 3a, 3b and 3c, one can see examples of cores likely to be used for manufacturing a part 1.

(20) In FIG. 3a is used a fusible core N through which axially passes a threaded rod T, in FIG. 3b is used a fusible core N provided at each of its ends with a threaded rod T′, while in FIG. 3c is used a core N that includes, from its manufacturing, at each of its ends an excrescence T″ in the form of a threaded rod.

(21) It should be noted that the core N can be made out of wax or preferably out of metal with a low melting point, while the threaded rods T and T′ are preferably polished and waxed.

(22) Of course, in the various above-mentioned methods, when we talk about winding fibers, it should be understood that the latter are embedded in a thermoplastic or thermosetting matrix, eventually by being pre-impregnated.

(23) It should be noted that, according to the method, it is possible to carry out a polymerization between each winding operation, or only one polymerization after the last winding operation, this also depending on the nature of the matrix used.