EP2179069B1 - Process for manufacturing a mechanical part including an insert made of a composite material - Google Patents

Description

The present invention relates to a method of manufacturing a mechanical part comprising an insert of composite material of the type consisting of ceramic fibers in a metal matrix. The invention applies to any type of mechanical part whose function is to transmit a traction force and / or compression mainly unidirectional.

In the aeronautical field, in particular, a constant objective is the optimization of the resistance of mechanical parts for a minimum mass and size. Thus, some mechanical parts may comprise an insert made of composite material with a metal matrix, such parts being able to be monobloc. Such a composite material comprises a matrix of metal alloy, for example titanium alloy Ti, within which fibers extend, for example ceramic fibers of SiC silicon carbide. Such fibers have a much higher tensile and compressive strength than titanium. It is therefore mainly the fibers that take up the efforts, the metal alloy matrix ensuring a binder function with the rest of the part, as well as protection and insulation of the fibers, which must not come into contact with each other. others. In addition, the ceramic fibers are resistant to erosion, but must necessarily be reinforced with metal.

The composite materials as described above are known to be used, in the aeronautical field, for the manufacture of disks, shafts, bodies of jacks, housings, spacers or as reinforcements of single-piece parts such as blades.

A technique for manufacturing these parts is described in the document FR 2886290 , representative of the technological background of the invention, in which one of the essential manufacturing steps consists in winding a bundle or a ply of coated wires around a circular part perpendicular to the axis of rotation of it. The described parts thus obtained are of circular type and are particularly suitable for producing circular parts such as shafts, cylinder bodies, housings or discs.

However, some mechanical parts require properties different from those presented by the circular parts. This is the case in particular connecting rods, essentially oblong shape, whose function is to transmit a tensile force and / or unidirectional compression.

The invention particularly relates to a method of manufacturing a mechanical part comprising at least one composite material insert of the type consisting of ceramic fibers in a metal matrix capable of transmitting tensile forces and / or unidirectional compression between its ends .

For this purpose, the invention relates to a method for manufacturing a mechanical part according to claim 1.

The mechanical part thus obtained, for example a connecting rod, advantageously makes it possible to transmit unidirectional traction and / or compression forces.

• la figure 1 représente une vue en perspective d'un exemple de pièce mécanique selon l'art antérieur ;
• la figure 2 représente une vue en perspective d'un exemple de dispositif de bobinage adapté pour la réalisation de l'invention ;
• la figure 3 représente une vue en perspective d'un exemple d'ébauche d'insert obtenu selon le procédé de fabrication de l'invention ;
• la figure 4 représente un exemple d'ébauche d'insert, d'un premier conteneur destiné à accueillir l'ébauche d'insert et de couvercle métallique destiné à recouvrir de manière étanche ledit conteneur et l'ébauche d'insert ;
• la figure 5 représente une vue en perspective d'un exemple d'une pièce intermédiaire obtenue au cours d'une étape du procédé de fabrication selon un premier mode de réalisation de l'invention ;
• la figure 6 représente un exemple d'insert, d'un second conteneur destiné à accueillir l'ébauche d'insert et de couvercle métallique destiné à recouvrir de manière étanche ledit conteneur et l'insert ;
• la figure 7 représente une vue en perspective d'un exemple de pièce mécanique obtenue selon le procédé de fabrication de l'invention ;
• la figure 8 représente une variante du procédé de fabrication de l'invention ;
• la figure 9 représente une vue en coupe d'un exemple de pièce mécanique obtenue selon la variante du procédé de fabrication de l'invention ; et
• la figure 10 représente une vue en perspective de l'exemple de pièce mécanique obtenue selon la variante du procédé de fabrication de l'invention.
• la figure 11 représente une vue schématique d'une ébauche d'insert selon un premier mode de réalisation de l'invention ;
• la figure 12 représente une vue schématique d'une ébauche d'insert selon un mode ne faisant pas partie l'invention ;
• la figure 13 représente une vue schématique d'une ébauche d'insert selon un mode ne faisant pas partie de l'invention ;
• la figure 14 représente une vue en perspective d'un exemple de dispositif de bobinage selon un mode ne faisant pas partie de l'invention ; et
• la figure 15 représente une vue en perspective d'un atterrisseur comportant une pièce mécanique selon l'invention.

Other advantages and features of the invention will emerge from the reading of the detailed description which follows with reference to the appended figures in which:

• the figure 1 is a perspective view of an example of a mechanical part according to the prior art;
• the figure 2 is a perspective view of an exemplary winding device adapted for carrying out the invention;
• the figure 3 is a perspective view of an example of an insert blank obtained according to the manufacturing method of the invention;
• the figure 4 is an example of insert blank, a first container for receiving the insert blank and metal cover for sealingly covering said container and the insert blank;
• the figure 5 is a perspective view of an example of an intermediate piece obtained during a step of the manufacturing method according to a first embodiment of the invention;
• the figure 6 is an example of an insert, a second container for receiving the blank insert and metal cover for sealingly covering said container and the insert;
• the figure 7 is a perspective view of an example of a mechanical part obtained according to the manufacturing method of the invention;
• the figure 8 represents a variant of the manufacturing method of the invention;
• the figure 9 represents a sectional view of an example of a mechanical part obtained according to the variant of the manufacturing method of the invention; and
• the figure 10 represents a perspective view of the example of mechanical part obtained according to the variant of the manufacturing method of the invention.
• the figure 11 is a schematic view of an insert blank according to a first embodiment of the invention;
• the figure 12 represents a schematic view of an insert blank according to a mode not forming part of the invention;
• the figure 13 is a schematic view of an insert blank according to a mode not forming part of the invention;
• the figure 14 is a perspective view of an exemplary winding device according to a mode not forming part of the invention; and
• the figure 15 represents a perspective view of an undercarriage comprising a mechanical part according to the invention.

The techniques for manufacturing a mechanical part, comprising an insert made of composite material, described in the document FR 2886290 can be used in the context of the present invention.

The figure 1 represents an example of a mechanical part such as a rod 1 whose shape is generally oblong, that is to say of elongated shape. It has two ends 13 and 14. The function of a connecting rod 1 is to transmit a movement, and / or tensile forces T and / or compression C, between two parts articulated at its ends along parallel axes Z1 and Z2 . The rod 1 has at each of its ends 13 and 14 a cylindrical recess 11 or 12 whose axes correspond to the parallel axes Z1 and Z2. This type of rod 1 can be used, for example, in the design of the undercarriages or in that of turbomachines comprising rods for taking up thrust force.

The figure 2 represents an example of winding device 20 according to a first embodiment of the invention. In this example, the winding device 20 is particularly suitable for producing an insert 3 for a mechanical part 10 or 110 such as a connecting rod. This winding device 20 comprises a hollow part 2 of oblong shape acting as a mandrel and two flanges 21 and 22 of oblong and substantially identical shape. The chuck part 2 has a geometry describing a closed structure most often curved. The dimensions of the flanges 21 and 22 are greater than the dimensions of the mandrel part 2 so that the periphery 27 of each flange 21 and 22 extends beyond the periphery of the mandrel part 2. The mandrel part 2 is sandwiched between the flanges 21 and 22. The threads 32 are wound on the mandrel piece 2 when the winding device 20 is rotated along the winding axis Z. The flanges 21 and 22 retain axially the son coatings 32 and guide them.

The winding device 20 belongs to an assembly forming a winding system. The winding system further comprises means for rotating the winding device 20 and means for providing a bundle or a bonded sheet of coated threads 32.

The chuck part 2 comprises two rectilinear winding portions 24. These straight winding portions 24 are oriented perpendicular to the winding axis Z. Thus, at least a part of the winding of the wires 32 around the mandrel part 2 is performs in a rectilinear direction. The winding of the coated wires 32 is carried out perpendicularly to the winding axis Z, in other words the coated wires 32 are substantially oriented perpendicularly to the winding axis Z.

In the example shown on the figure 2 these rectilinear winding portions 24 are parallel and interposed between two circular portions 25. It is possible to vary the dimensions of the chuck part 2, in particular its thickness in the axial direction Z, the length of the rectilinear winding portions 24 and the radius of curvature of the circular parts 25, depending on the dimensions of the desired insert 3. The circular pieces 25 may also have different radii. Thus, the portions of rectilinear windings 24 may not be parallel.

The winding around the mandrel part 2 having rectilinear winding portions 24 makes it possible to generate in a short time an insert blank 33 comprising at least one rectilinear generator consisting of a large number of parallel and unidirectional coated wires 32.

The blank 33 of insert 3, once wound, can be removed from the winding device 20 by separating the flanges 21 and 22 from one another. The shape of the blank 33 of insert 3 thus formed must be fixed to prevent the son 32 lose their orientation. Several techniques can be implemented for this purpose.

A first technique for maintaining the blank 33 of insert 3 consists in providing, at the beginning of winding, a step of winding a first metallic tinsel of attachment of the inner part of insert blank 33 3 and, at the end of winding, a step of winding a second metallic flashing 28 of attachment of the outer part of the blank 33 of insert 3. In this example, the first metal foil constitutes the mandrel piece 2 The coated threads 32 are thus between the foils 2 and 28, as shown in FIG. figure 3 .

Moreover, as illustrated on the figure 2 each flange 21 and 22 has notches 23 on its periphery 27. Each notch 23 of the flange 21 is disposed vis-à-vis a notch 23 of the flange 22, thus forming a pair of notches 23. The fixing of the metal straps 31 is facilitated by the dimensions of the notches 23 extending inwardly of the flanges 21 and 22 to a depth d. The depth d of the notches 23 must be such that it is possible to access the hollow interior 29 of the chuck part 2 which is arranged around a hub of the winding device 20, not visible on the figure 2 , comprising an alternation of notches and teeth, the notches of the hub being in phase with the notches 23 of the flanges 21 and 22. The depth d extends beyond the winding surface of the mandrel piece 2.

Each pair of notches 23 is intended to allow the attachment of a metal strap 31. The metal straps 31 are made of a metallic material identical to that of the containers 4 and 104, described in connection with the figures 4 and 6 and the mandrel piece 2. The metal straps 31 are fixed around the insert blank 33 by a contact welding process. The metal straps 31 are arranged at regular intervals on the blank 33 wound insert 3.

Once the blank insert 33 wound 3 and the metal straps 31 in place, it can be removed from the winding device 20 by separating the flanges 21 and 22 from one another. An example of blank 33 of insert 3 thus obtained is shown in FIG. figure 3 . It consists of an elongated mandrel-shaped part comprising two rectilinear and parallel portions 34 interposed between two circular portions 35.

A second technique for holding in the form of the blank 33 of insert 3, which does not require the use of straps 31, consists in providing a mandrel-forming piece 2 forming an oblong mandrel comprising at least one radial flange, for example with a section transverse L-shaped or U-shaped, on which the threads 32 are wound. When a bonded ply of coated threads 32 is used, it is possible to secure it to the mandrel piece 2 on which it is wound and to the ply. the lower layer by means of a method by contact welding between two electrodes and passage of a medium frequency current. The wires 32 are thus welded as the winding progresses so that, when the insert blank 33 is extracted from the winding device 20, it forms a part integral with the mandrel part 2.

The insert blank 33 is then inserted into a first container 4, as shown in FIG. figure 4 . The container 4 comprises for this purpose a groove 41 of complementary shape to the blank 33 of insert 3 and in which is housed the insert blank 33 3. A lid 5 is attached to the container 4 by beam welding of electrons, evacuated, and then compacted by a hot isostatic compaction process. The piece thus obtained, represented on the figure 5 contains the insert blank 33 3. In the insert insert 33 describing a revolution, the parts which most effectively contribute to transmitting unidirectional tensile and / or compression forces are the rectilinear portions 34 of coated threads. 32. The method of hot isostatic compaction is followed by a machining step for extracting at least one rectilinear portion 34 forming an insert 3.

As shown on the figure 6 the inserts 3 obtained after machining are then inserted into a second container 104. The second container 104 has for this purpose grooves 141 of complementary shape to the inserts 3 and in which are housed the inserts 3. A lid 105 is attached to the container 104 by electron beam welding, evacuated, and then compacted by a hot isostatic compaction process. On the figure 6 the inserts 3 are arranged in the second container 104 in a parallel manner. It is also possible to arrange them in a non-parallel manner depending on the shape of the desired final mechanical part. It is also possible to insert only one insert 3 into a container 104 depending on the dimensions of the desired final mechanical part.

The assembly is then machined to obtain the final mechanical part 10: a rod 10, represented on the figure 7 . The rod 10, of identical shape to the rod 1 of the figure 1 , further comprises a plurality of composite material insert 3, the son 32 are oriented in a rectilinear direction. This rectilinear direction is perpendicular to the axes Z1 and Z2. This link 10 advantageously allows to transmit the unidirectional traction and / or compression forces. All the son of an insert 3 are oriented in the same rectilinear direction.

The invention applies to any type of mechanical part whose function is to transmit a traction force and / or compression mainly unidirectional and is therefore not limited only to connecting rods that are only an example of application.

According to one variant, the mechanical part may be of more complex shape and comprise a plurality of inserts 3, each insert 3 comprising wires 32 oriented in a rectilinear direction. In the example shown in figure 8 , the manufacturing method is modified by using a second container 104 having on either side of two of its opposite faces 42 grooves 41 for receiving inserts 3. After hot isostatic compaction and machining, the mechanical part 110 obtained is the one represented in figure 9 and thus comprises inserts 3. The inserts 3 are positioned on either side of a median plane P1 of the mechanical part 110. They are positioned in planes P2 and P3 forming an angle α not zero between them. The figure 10 shows, in perspective, a mechanical part 110 thus obtained. This mechanical part 110 may also include recesses 15 intended to reduce the mass.

According to a mode not forming part of the invention, represented at figure 12 , a chuck part 2, comprising portions of rectilinear coil 24 longer than those of the first embodiment, is used. In this way, it is possible to extract and manufacture a larger number of inserts 3. To do this, the blank 133 is cut by extracting several inserts 3 on the same rectilinear portion 34 of the blank 133.

The figure 11 corresponds to the invention.

According to a mode not forming part of the invention, a large number of inserts 3 can be obtained by the use of a piece forming a polygon-shaped mandrel, that is to say a mandrel piece 220 comprising a plurality of rectilinear winding portions 224. The figure 13 represents an example of blank 233 of inserts 3 obtained according to this third embodiment. The polygon-shaped blank 233, shown by way of example, is a hexagon comprising six rectilinear portions 34 and twelve cutting planes 36. It is possible to obtain a number of inserts different from six by using a polygon comprising a number of sides less than or greater than six.

To obtain such a blank, it is necessary to use a winding device 220 comprising a mandrel piece 202 in the form of a polygon, this mandrel piece 202 being preferably able to be sandwiched into two flanges 221 and 222 in form. of polygon. The winding device 220 of this mode not forming part of the invention, represented on the figure 14 , has common features with the winding device 20 of the first embodiment of the invention by the presence of the notches 223 on its periphery 227 and the hollow interior 229 of the mandrel piece 202 in the form of a polygon, its operation being identical.

Such mechanical parts 10 or 110 are perfectly suitable for aeronautical applications, for example for undercarriages or for turbomachines intended for an aircraft.

An example of an undercarriage 6 is shown in figure 15 . An undercarriage 6 comprises a box 61, constituting the major structural part, and arms 62. The arms 62 are intended to transmit a mainly unidirectional traction and / or compression force. The arms 62 may therefore constitute mechanical parts according to the invention without forming rods 110. In this case, the inserts 3 are contained in the arms 62.

Claims (3)

1. A method of manufacturing a mechanical component (10, 110) comprising at least one insert (3) made of metal matrix composite, within which matrix ceramic fibers extend, the composite insert (3) being obtained from a plurality of coated filaments (32) each comprising a ceramic fiber coated with a metal sheath, the method involving manufacturing an insert (3) preform (33) with a step of winding a bonded lap or bundle of coated filaments (32) about a part forming a mandrel (2, 202), wherein at least some of the winding is done in at least one rectilinear direction, and which method further comprises:

   • a step of inserting the insert (3) preform (33) in a first container (4);

   • a step of hot isostatic compaction of the first container (4); and

   • a step of machining the first container (4) to form a rectilinear insert (3).

   • a step of inserting the insert (3) in a second container (104);

   • a step of hot isostatic compaction of the second container (104); and

   • a step of machining the second container (104) to form a mechanical component (10).
2. The method of manufacturing a mechanical component (10, 110) as claimed in claim 1, wherein the part forming a mandrel (2) has two rectilinear winding portions (24), fitted in between two circular portions (25).
3. The method of manufacturing a mechanical component (10, 110) as claimed in claim 1, wherein winding is performed around a part forming a mandrel (202), of polygonal shape.

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