Abstract:
A method of manufacturing a mechanical component, and winding device to implementing the method. The component includes at least one insert of metal matrix composite, within which matrix ceramic fibers extend, the composite insert obtained from a plurality of coated filaments each including a ceramic fiber coated with a metal sheath. The method manufactures an insert preform by winding a bonded lap or bundle of coated filaments about a cylindrical component. At least some of the winding is performed in at least one rectilinear direction. The method further inserts the insert preform in a first container; performs hot isostatic compaction of the first container; and machines the first container to form a rectilinear insert.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a mechanical component comprising an insert made of composite of the type consisting of ceramic fibers in a metal matrix, and to a method of manufacturing this mechanical component and to a winding device designed to implement the method of manufacture. The invention applies to any kind of mechanical component the purpose of which is to transmit a tensile and/or compressive force chiefly in one direction. 
         [0002]    In the field of aeronautical engineering in particular, there is a constant drive toward optimizing the strength of mechanical components for minimal mass and size. Hence, certain mechanical components may have an insert made of metal matrix composite, it being possible for such components to be of one piece. A composite such as this comprises a metal alloy matrix, for example made of titanium Ti alloy, within which fibers, for example ceramic silicon carbide SiC fibers, extend. Such fibers have a far higher tensile and compressive strength than titanium. It is therefore mainly the fibers that react the load, the metal alloy matrix acting as a binder connecting to the remainder of the component, as well as protecting and insulating the fibers, which have not to come into contact with one another. Furthermore, the ceramic fibers are resistant to erosion, but it is essential that they be reinforced with metal. 
         [0003]    The composites as described hereinabove are known for their use, in the field of aeronautical engineering, in the manufacture of disks, shafts, the bodies of actuating cylinders, casings, struts or as reinforcements for one-piece components such as vanes. 
       DESCRIPTION OF THE PRIOR ART 
       [0004]    One technique for manufacturing these components is described in document FR 2886290, which represent the technological background of the invention, in which document one of the essential steps in the manufacture consists in winding a bundle or lap of coated filaments around a circular component of revolution perpendicular to the axis of rotation thereof. The described components obtained in this way are of circular type and are mainly suited to the production of circular components such as shafts, the bodies of actuating cylinders, casings or disks. 
         [0005]    However, some mechanical components require properties that differ from those exhibited by circular components. This is particularly the case of rods, which are essentially oblong in shape, and the purpose of which is to transmit a tensile and/or compressive load in one direction. 
       SUMMARY OF THE INVENTION 
       [0006]    One particular subject of the invention is a method of manufacturing the mechanical component comprising at least one insert made of a composite of the type consisting of ceramic fibers in a metal matrix that is capable of transmitting tensile and/or compressive loads in one direction between its ends. 
         [0007]    To this end, the invention relates to a method of manufacturing a mechanical component comprising at least one insert made of metal matrix composite, within which matrix ceramic fibers extend, the composite insert being obtained from a plurality of coated filaments each comprising a ceramic fiber coated with a metal sheath, the method involving manufacturing an insert preform with a step of winding a bonded lap or bundle of coated filaments about a component of revolution. According to the invention, at least some of the winding is done in at least one rectilinear direction. The method further comprises:
       a step of inserting the insert preform in a first container;   a step of hot isostatic compaction of the first container; and   a step of machining the first container to form a rectilinear insert.       
 
         [0011]    Once the insert has been manufactured, the method of manufacturing a mechanical component is followed by the following steps:
       a step of inserting the insert in a second container;   a step of hot isostatic compaction of the second container; and   a step of machining the second container to form a mechanical component.       
 
         [0015]    The mechanical component thus obtained, for example a rod, is advantageously able to transmit tensile and/or compressive loads in one direction. 
         [0016]    The invention also relates to a winding device specially designed to implement the method of manufacture according to the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0017]    Further advantages and features of the invention will become apparent from reading the detailed description which follows, with reference to the attached drawings in which: 
           [0018]      FIG. 1  is a perspective view of one example of a mechanical component according to the prior art; 
           [0019]      FIG. 2  is a perspective view of one example of a winding device according to a first embodiment of the invention; 
           [0020]      FIG. 3  is a perspective view of one example of an insert preform obtained according to the method of manufacture of the invention; 
           [0021]      FIG. 4  is one example of an insert preform, of a first container intended to accommodate the insert preform and of a metal lid intended to seal said container and the insert preform; 
           [0022]      FIG. 5  is a perspective view of one example of an intermediate component obtained during one step of the method of manufacture according to a first embodiment of the invention; 
           [0023]      FIG. 6  is one example of an insert, of a second container intended to accommodate the insert preform and of a metal lid intended to seal said container and the insert; 
           [0024]      FIG. 7  is a perspective view of one example of a mechanical component obtained according to the method of manufacture of the invention; 
           [0025]      FIG. 8  is an alternative form of the method of manufacture of the invention; 
           [0026]      FIG. 9  is a cross section through one example of a mechanical component obtained according to the alternative form of the method of manufacture of the invention; 
           [0027]      FIG. 10  is a perspective view of the example of a mechanical component obtained according to the alternative form of the method of manufacture of the invention; 
           [0028]      FIG. 11  is a schematic view of an insert preform according to a first embodiment of the invention; 
           [0029]      FIG. 12  is a schematic view of an insert preform according to a second embodiment of the invention; 
           [0030]      FIG. 13  is a schematic view of an insert preform according to a third embodiment of the invention; 
           [0031]      FIG. 14  is a perspective view of one example of a winding device according to a third embodiment of the invention; and 
           [0032]      FIG. 15  is a perspective view of an undercarriage comprising a mechanical component according to the invention. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    The techniques of manufacturing a mechanical component comprising an insert made of composite, as described in document FR 2886290, can be used in the context of the present invention. Thus, the teaching of that document is to be considered to be incorporated into this application and, for example, and nonlimitingly, the structure of the coated filaments, the manufacture thereof, the manufacture of a bonded lap of coated filaments, the securing of this lap either to the metal support onto which it is wound or onto the lap of the layer below, the laser-welding of the filaments or their welding by contact between two electrodes, the hot isostatic compaction and machining. 
         [0034]      FIG. 1  depicts one example of a mechanical component such as a rod  1  the shape of which is oblong overall, that is to say of elongate shape. It has two ends  13  and  14 . The purpose of a rod  1  is to transmit a movement and/or tensile T and/or compressive C forces between two components articulated to the ends thereof about parallel axes Z 1  and Z 2 . The rod  1 , at each of its ends  13  and  14 , has a cylindrical recess  11  or  12 , the axes of which correspond to the parallel axes Z 1  and Z 2 . This type of rod  1  may be used, for example, in the design of undercarriages or in that of turbomachines comprising thrust rods. 
         [0035]      FIG. 2  depicts an example of a winding device  20  according to a first embodiment of the invention. In this example, the winding device  20  is particularly well suited to create an insert  3  for a mechanical component  10  or  110  such as a rod. This winding device  20  comprises a component  2  of revolution that is hollow and of oblong shape acting as a mandrel and two end plates  21  and  22  of oblong shape and substantially identical. The component of revolution  2  has a geometry of revolution, that is to say a geometry that describes a closed structure, usually curved. The dimensions of the end plates  20  and  22  are greater than the dimensions of the component of revolution  2  which means that the periphery  27  of each end plate  21  and  22  extends beyond the periphery of the component of revolution  2 . The component of revolution  2  is sandwiched between the end plates  21  and  22 . The filaments  32  are wound onto the component of revolution when the winding device  20  is rotated about the winding axis Z. The end plates  21  and  22  axially retain the coated filaments  32  and wind them. 
         [0036]    The winding device  20  belongs to an assembly that forms a winding system. The winding system further comprises means for rotating the winding device  20  and means for supplying a bonded lap or bundle of coated filaments  32 . 
         [0037]    The component of revolution  2  comprises two rectilinear winding portions  24 . These rectilinear winding portions are directed perpendicular to the winding axis Z. Thus, at least some of the winding of the filaments  32  about the component of revolution  2  is done in a rectilinear direction. The winding of the coated filaments  32  is performed perpendicular to the winding axis Z, or in other words, the coated filaments  32  are directed substantially perpendicular to the winding axis Z. 
         [0038]    In the example depicted in  FIG. 2 , these rectilinear winding portions  24  are parallel and fitted in between two circular portions  25 . It is possible to vary the dimensions of the component of revolution  2 , particularly 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 , according to the dimensions of the desired insert  3 . The circular parts  25  may also have different radii. Thus, the rectilinear winding portions  24  may be non-parallel. 
         [0039]    Winding around the component of revolution  2  comprising rectilinear winding portions  24  makes it possible, in a short space of time, to generate an insert  3  preform  33  having at least one rectilinear generatrix consisting of a great many parallel and uni-directional coated filaments  32 . 
         [0040]    The insert  3  preform  33 , once wound, can be removed from the winding device  20  by detaching the end plates  21  and  22  from one another. The shape of the insert  3  preform  33  thus formed needs to be set so as to prevent the filaments  32  from losing their orientation. There are various techniques that can be employed to achieve this. 
         [0041]    One first technique for maintaining the shape of the insert  3  preform  33  is to provide, at the start of winding, a step of winding a first metal foil that secures the internal part of the insert  3  preform  33  and to provide, at the end of winding, a step of winding a second metal foil  28  that secures the external part of the insert  3  preform  33 . In this example, the first metal foil constitutes the component of revolution  2 . The coated filaments  32  therefore find themselves between the foils  2  and  28  as depicted in  FIG. 3 . 
         [0042]    Moreover, as illustrated in  FIG. 2 , each end plate  21  and  22  has slots  23  on its periphery  27 . Each slot  23  of the end plate  21  is positioned facing a slot  23  of the end plate  22 , thus forming a pair of slots  23 . The fitting of metal bands  31  is made easier by the dimensions of the slots  23  extending toward the inside of the end plates  21  and  22  over a depth d. The depth d of the slots  23  has to be such that it is possible to access the hollow inside  29  of the component of revolution  2 , which is positioned around a hub of the winding device  20 , not visible in  FIG. 2 , comprising an alternation of slots and of teeth, the slots of the hub being in register with the slots  23  of the end plates  21  and  22 . The depth d extends beyond the winding surface of the component of revolution  2 . 
         [0043]    Each pair of slots  23  is intended to allow the attachment of a metal band  31 . The metal bands  31  are made of a metallic material identical to that of the containers  4  and  104 , described in conjunction with  FIGS. 4 and 6 , and of the component of revolution  2 . The metal bands  31  are fixed around the insert  3  preform  33  by a contact welding process. The metal bands  31  are positioned at regular intervals along the wound insert  3  preform  33 . 
         [0044]    Once the insert  3  preform  33  has been wound and the metal bands  31  have been fitted, this preform can be removed from the winding device  20  by detaching the end plates  21  and  22  from one another. An example of an insert  3  preform  33  thus obtained is depicted in  FIG. 3 . This consists of a component of revolution of oblong shape comprising two rectilinear and parallel portions  34  fitted in between two circular portions  35 . 
         [0045]    A second technique for keeping the insert  3  preform  33  in shape, that does not involve the use of bands  31 , is to provide a component of revolution  2  forming an oblong mandrel comprising at least one radial rim, for example with an L-shaped or U-shaped cross section, onto which the filaments  32  are wound. When a bonded lap of coated filaments  32  is used, it is possible to secure it to the component of revolution  2  onto which it is wound and to the lap of the layer below using a method of contact welding between two electrodes and by passing a medium frequency current. The filaments  32  are thus welded together as winding progresses which means that when the insert  3  preform  33  is removed from the winding device  20 , it forms a component as one with the component of revolution  2 . 
         [0046]    The insert  3  preform  33  is then inserted in a first container  4 , as depicted in  FIG. 4 . The container  4  for this purpose comprises a groove  41  of a shape that complements the insert  3  preform  33  and into which the insert  3  preform  33  is housed. A lid  5  is attached to the container  4  by electron welding, is evacuated, then compacted using a hot isostatic compaction process. The component thus obtained, depicted in  FIG. 5 , contains the insert  3  preform  33 . In the insert  3  preform  33  that describes a revolution, the parts that make the most effective contribution toward transmitting one-way tensile and/or compressive forces are the rectilinear portions  34  of coated filaments  32 . The hot isostatic compaction process is followed by a machining step aimed at extracting at least one rectilinear portion  34  forming an insert  3 . 
         [0047]    As depicted in  FIG. 6 , the inserts  3  obtained after machining are then inserted in a second container  104 . The second container  104  for this purpose has grooves  141  of a shape that complements the inserts  3  and in which the inserts  3  become housed. A lid  105  is attached to the container  104  by electron welding, is evacuated, then compacted using a hot isostatic compaction process. In  FIG. 6 , the inserts  3  are arranged parallel in the second container  104 . It is equally possible to arrange them non-parallel, depending on the shape of the desired finished mechanical component. It is also possible to insert just one insert  3  in a container  104 , depending on the dimensions of the desired finished mechanical component  10 . 
         [0048]    The whole is then machined to obtain the finished mechanical component  10 : a rod  10 , depicted in  FIG. 7 . The rod  10 , identical in shape to the rod  1  in  FIG. 1 , further comprises a plurality of inserts  3  made of composite, the filaments  32  of which are directed in a rectilinear direction. This rectilinear direction is perpendicular to the axes Z 1  and Z 2 . This rod  10  is advantageously able to transmit one-way tensile and/or compressive forces. All the filaments of an insert  3  are directed in one and the same rectilinear direction. 
         [0049]    The invention applies to any type of mechanical component the function of which is to transmit a tensile and/or compressive force mainly in one direction and is therefore not restricted solely to rods, which are just one application example. 
         [0050]    According to an alternative form of the invention, the mechanical component may be of more complex shape and comprise a plurality of inserts  3 , each insert  3  comprising filaments  32  directed in a rectilinear direction. In the example depicted in  FIG. 8 , the method of manufacture is modified by using a second container  104  which comprises, on each side of two of its opposing faces  42 , grooves  41  intended to accommodate inserts  3 . Following hot isostatic compaction and machining, the mechanical component  110  obtained is that depicted in  FIG. 9  and thus comprises inserts  3 . The inserts  3  are positioned on each side of a mid-plane P 1  of the mechanical component  110 . They are positioned in planes P 2  and P 3  that are at a non-zero angle α to one another.  FIG. 10  is a perspective view of a mechanical component  110  thus obtained. This mechanical component  110  may equally have recesses  15  intended to reduce the weight thereof. 
         [0051]    According to a second embodiment of the invention, depicted in  FIG. 12 , a component of revolution  2 , comprising rectilinear winding portions  24  longer than those of the first embodiment, is used. Thus, it is possible to extract and manufacture a greater number of inserts  3 . To do this, the preform  133  is cut, extracting several inserts  3  from one and the same rectilinear portion  34  of the preform  133 . 
         [0052]      FIG. 11  corresponds to the first embodiment of the invention. 
         [0053]    According to the third embodiment of the invention, a great many inserts  3  can be obtained by using a component of revolution  233  of polygonal shape, that is to say a component of revolution  220  comprising a plurality of rectilinear winding portions  224 .  FIG. 13  depicts one example of an insert  3  preform  233  obtained according to this third embodiment. The preform  233  of polygonal shape, depicted 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 other than six by using a polygon having more than or less than six sides. 
         [0054]    To obtain such a preform, it is necessary to use a winding device  220  comprising a component of revolution  202  of polygonal shape, it being possible for this component of revolution  202 , preferably, to be sandwiched between two polygonal end plates  221  and  222 . The winding device  220  of the third embodiment according to the invention, depicted in  FIG. 14 , has features in common with the winding device  20  of the first embodiment of the invention because is has slots  223  on its periphery  227  and because the inside  229  of the polygonal component of revolution  202  is hollow, its operation being identical. 
         [0055]    Such mechanical components  10  or  110  are perfectly suited to aeronautical applications, for example to undercarriages or to the turbomachines intended for an aircraft. 
         [0056]    An example of an undercarriage  6  is depicted in  FIG. 15 . An undercarriage  6  comprises a box  61 , constituting the major structural component, and arms  62 . The arms are intended to transmit a tensile and/or compressive force mainly in one direction. The arms  62  may therefore constitute mechanical components according to the invention without actually forming rods  110 . In this case, the inserts  3  are contained in the arms  62 .