EP3038814A1

EP3038814A1 - Key tool and composite panel, in particular for an aircraft engine nacelle, produced using such a tool

Info

Publication number: EP3038814A1
Application number: EP14790160.7A
Authority: EP
Inventors: Eric Pillon; Christophe MAHU; Denis GRENET
Original assignee: Aircelle SA
Current assignee: Safran Nacelles SAS
Priority date: 2013-08-28
Filing date: 2014-07-30
Publication date: 2016-07-06
Also published as: US20160167316A1; FR3009992B1; WO2015028736A1; FR3009992A1

Abstract

The key tool of the invention comprises at least two keys having adjacent edges, the tool (14, 15) being substantially cylindrical in shape with a central axis, the adjacent edges being substantially parallel to the central axis. The adjacent edges have covers (20, 21) that are tangential relative to the inner and/or outer surface of the key tool. Application to the production of composite panels, in particular for an aircraft engine nacelle.

Description

Key tools and composite panel, in particular for an aircraft engine nacelle manufactured using such tools

The present invention relates to a key tool with flat junction and a composite panel in particular for aircraft engine nacelle manufactured using such tooling.

The present invention relates to the field of the manufacture of composite parts by draping folds on a key tool.

More particularly, when a composite part extends over more than 180 ° of revolution and has a convex shape, it is necessary to manufacture it with a key tool.

This tool has an outer shape corresponding to the inner shape of the part to be manufactured, and is formed of a plurality of sectors - or keys, which can be disassembled once the part manufactured.

In practice, the production of the part first requires a step of compacting the folds on the outer wall of the key tool, then a step of migration of the resin in the folds, and polymerization of this resin.

These compaction and resin migration steps, which are carried out under vacuum thanks to an external bladder that envelops the folds arranged on the key tools, require perfect sealing of the joints between the different sectors of the tooling. key.

In practice, this seal is obtained by means of a bladder internal to the tooling, which is placed under vacuum so that it comes to press against the joint lines between the different sectors of the tooling.

These joint lines are conventionally defined by radial returns of the different sectors forming the key tool, these returns being fixed together by bolts.

These returns thus form protuberances towards the inside of the tooling, which protuberances are likely to tear the internal bladder, and thus to compromise the desired seal.

The present invention aims to remedy this, and thus proposes a key tool in which the edges of the sectors have mutual contact surfaces which are circumferential, and preferably provided with joints.

With this particular arrangement, it provides a seal to do without a bladder internal tooling, or to put only partial internal bladders covering only the joint line.

In an arrangement according to the invention, there are no more radial returns of the different sectors of the tooling, so that in the case of the implementation of partial internal bladders, there is no longer any risk of tearing of these bladders, as was the case in the prior art.

To this end, the invention relates to a key tool of the type comprising at least two keys having adjacent edges, the tool having a substantially cylindrical shape of central axis, the adjacent edges being substantially parallel to the central axis. According to the invention, the adjacent edges have tangential overlaps relative to the inner and / or outer surface of the key tool.

According to other additional features of the invention:

the tangential covering of two adjacent edges of the keys comprises a thinning of a first edge of an inner side of the tooling vis-à-vis a thinning of a second edge of an outer side of the tooling so that no extra thickness is introduced on the inner and / or outer surface of the key tool;

the tangential recovery portions of two adjacent edges cooperate with a seal;

at least one tangential overlap of adjacent edges of keys is covered by an inner and / or outer partial bladder, two seals substantially parallel to the central axis of the key tool being arranged on either side of said at least one tangential overlap between the inner and / or outer partial bladder and the inner and / or outer surface of the key tool;

an inner or outer partial bladder cooperates with an outer or inner bladder, respectively, by means of a return passing over the annular edge of the key tool and a tab coming into contact with a seal on the surface facing a counterpart of said outer bladder, respectively inner;

a seal is disposed on an annular edge of the key tool so as to seal an inner or outer partial bladder at its return; the key tool cooperates with at least one inner and outer partial bladder, and an outer and inner full bladder, respectively;

the key tool cooperates with only a complete outer bladder, respectively inner;

keys are secured by tangential connection means to bolt or stud, and / or by a key binding system and manipulation.

The invention finally relates to a composite panel, in particular for an aircraft engine nacelle, having a symmetry of revolution and comprising a pleated draped preform, shaped, compacted and impregnated with resin using a key tool according to the invention. .

Other features and advantages according to the present invention will be better understood with the help of the description and the drawings, among which:

Figures 1a and 1b show a schematic view and a detail of the schematic view of a key tool with bladders according to the state of the art;

Figures 2a and 2b show a schematic view and a detail of the schematic view of a key tool with bladders according to a first embodiment of the invention;

Figures 3a and 3b show a schematic view and a detail of the schematic view of a key tool with bladders according to a second embodiment of the invention;

Figures 4a and 4b show schematic perspective views of tools according to another embodiment of the invention; and

Figure 5 shows a partial sectional view of bladders used in the embodiment of Figures 4a and 4b.

In Figure 1a, there is shown a schematic view of a key tool with bladders according to the state of the art. The key tool 1 is seen from above with an inner bladder 2. Of course, around the central axis of the key tool of substantially cylindrical shape, shape variations are provided in the radial direction and which are not not shown to simplify the drawing. Four sectors or keys have been represented as sectors 5, 6 and 7. Each sector 5, 6 or 7 is limited by a substantially radial return and directed towards the inside of the tooling. Radial returns such as return 3, require that the inner bladder 2 has longitudinal pockets, along the central axis of the tooling to surround closer to the inner surface of the tooling.

To improve the seal, as shown in Figure 1a on the return 4, the gap between two key edge bends (or sector) is lined with a seal.

In Figure 1b, there is shown the detail of a radial return between the keys 6 and 7. The key 6 has a folded edge 8 which returns to the inside of the tool. The key 7 has a folded edge 9 which is disposed substantially parallel to the folded edge 8. A seal, as for the return 4 (Figure 1a) can be inserted. Step by step the radial edge connection means such as the bolt 10 are arranged to secure the keys 6 and 7 on the radial return 8, 9. Note that their number can be high which makes the assembly and disassembly operations of the key tools during production quite long.

An inner bladder 2 sealing must still be disposed on the inner surface of the key tool. It is therefore necessary to form a pocket 1 1 to surround closely the radial return 8, 9. But during the pressurization or depression, during the introduction and removal of the inner bladder 2, there is a high risk tearing of the inner bladder on radial returns.

In Figure 2a is shown in plan view, a new key tool arrangement according to a first embodiment. In this embodiment, the edges facing the keys are no longer oriented radially but substantially along the tangent to the inner surface of the key tool at the point of connection between the two keys facing each other. The tangential overlap of the edges of two adjacent keys is such that the edges of the sectors or keys have mutual contact surfaces which are circumferential with respect to the central axis of the key tool.

There is shown a tool with four keys or cylindrical sectors. Another number of keys, from three to five for example, is planned.

In a first embodiment, the edges of the keys are folded so as to reduce the extra thickness provided by the tangential returns formed by these folded edges. Their attachment may include the same kind of bolts as in the state of the art. The four keys of the tool thus have four tangential returns as the tangential return 12 between the keys. Due to the circumferential overlap of the opposite edges, this "tangential recovery" arrangement to indicate that the direction of overlap is perpendicular to that of the state of the art.

Then there is not a single inner bladder making the entire inner surface of the key tool, but two partial inner bladders 18 and 18 ', arranged inside the smaller keys as the key 15 and the two bladders inner partial covering a sector wide enough to cover tangential overlays on both sides of each "small" key, such as key 15.

In the embodiment shown in FIG. 2a (the same thing being true for FIG. 3a), the structure of each key is a "thin" structure, that is to say whose thickness in the radial direction n ' is not taken into account. The edges of the "thin" structures are then bent so that the bearing direction is substantially in a radial direction relative to the central axis of the key tool. It follows that the support of the adjacent edges executes in front support when forces are applied to the key tool during its use for the manufacture of a composite panel comprising, in particular, the compaction of the initial preform, then its impregnation of resin.

Note that the tangential overlap 12 of the adjacent edges of the keys causes a moderate oversize on the inner surface of the tool so that the pocket 19 of the partial inner bladder 18 has a reduced height when compared to the height of the pockets. the single inner bladder of the state of the art (Figures 1a and 1b) in which the overlaps of the edges are radial and in which the supports then work in shear, which is not a satisfactory solution.

In addition, the cutting parts of the radial return of the state of the art (Figure 1a or 1b) no longer exist, since the edges of the keys are folded substantially along the local tangent to the inner surface of the tool to key. This solves the problem of tears of the inner bladder, in particular because the radial return is removed and also because the inner bladder has been separated into two parts more easily manipulated by an operator during the steps of production of the ferrule.

Of course, it is possible to have more than two partial internal bladders such as the partial inner bladders 18 and 18 '. For example, if only two keys are used to carry out all the key tools, including a small key, covering an angular sector a narrow key, for example 60 ° and a large key, covering a wide angular sector, for example 320 °, it is then expected to have a single partial inner bladder covering the angular sector of the narrow key and beyond beyond to provide, beyond the tangential overlaps of the key edges, sealing adhesive strips between the inner wall of the key and the wall facing the partial inner bladder.

This arrangement is illustrated in Figure 2a for an embodiment with four keys and two partial inner bladders. The inner partial bladder 18, disposed on the inner surface of the key 15 of small angular extent, extends beyond the tangential overlays such as the tangential lap 12, and the other tangential lap without reference but on the key 15, the On the other side of each of the tangential overlays are adhesive sealing strips 13 and 14. The seal 13 is disposed between the inner surface of the key 16 and the facing surface of the partial bladder 18. The seal sealing 14 is disposed between the inner surface of the key 17 and the surface facing the partial bladder 18.

Of course, the same provisions are repeated on the second inner partial bladder 18 'and they are not recalled.

FIG. 2b shows a detail of a tooling of the first embodiment of FIG. 2a, but in which the tangential covering is made by a particular conformation of the edges facing two successive keys and in which a seal is disposed between the partial partial bladder and an outer bladder.

The two adjacent keys 14 and 15 are made of a thick structure, and they have edges intended to overlap tangentially in their thickness so that their overlap does not introduce any extra thickness on the inner surface of the key tool when the keys are assembled and secured by means of removable means for securing keying tool wrenches.

In another embodiment, the homologous edges of two adjacent keys are also shaped so that in their tangential covering, no excess thickness is introduced on the outer surface of the key tool when the keys are assembled and secured to using known means for removable attachment of key tools.

Thus, in FIG. 2b, the edge of the right-hand key 14 has a thinning on the inside of the key tool in its thickness. while the edge of the left wrench 15 has a thinning 21 of the outer side of the key tool in its thickness. The thinned edges 20 and 21 are shaped so that their tangential coating does not introduce any extra thickness on the inner surface or on the outer surface of the key tool thus formed.

To provide guidance when mounting the key 15 from inside the key tool on the key 14 and on the other key (not visible on the other side of the key 15) the homologous edge has the right of the thinning 20 a chamfer 22 which guards the end of the thinning 21 of the homologous edge of the key 15.

To ensure a seal between the limited internal volume between the inner partial bladder 18 and the inner surface of the key tool, tangential overlap 20, 21 is arranged a seal 23 engaged in a parallel elongated groove to the central axis of the key tool. The groove is made along the thinning 21 of the right edge of the key 15 vis-à-vis the thinning 20 of the left edge of the key 14. The seal 23 is disposed over the entire height of the tooling key in the direction of the central axis of the key tool.

An outer bladder 28, partially shown in Figure 2b, completely surrounds the outer surface of the key tool beyond the wrenches 14 and 15. The view of Figure 2b is a view from above, there is shown schematically a return 26 of the inner partial bladder 18 which passes over the upper edge (not shown to show the tangential overlap structure of the edges of the adjacent keys 14 and 15). The seal between the inner partial bladder 18 and the outer bladder 28 is made in particular by means of a seal 24 made between a flap 27 integral with the return 26 of the partial partial bladder 18 which passes over the upper edge of the key tool.

The seal of the inner partial bladder 18 is completed with another seal deposited between the inner partial bladder 19 and the inner surface of the key 14 close to the right of the tangential covering 20, 21.

Of course, the same arrangements, including sealing, are practiced on the left at the tangential overlap as the tangential covering 12 (Figure 2a) on the other tangential covering made between the left edge of the key 15 and the edge of the adjacent key on the left (not visible in Figure 2b). In Figure 3a, there is shown another embodiment of a key tool according to the invention. It comprises four keys 30 - 33 including two narrow keys 30 and 32. The four keys are joined by four tangential covers each covered by its own inner partial bladder 38 -41. Each internal partial bladder such as the bladder 38 is associated with the inner surface of the key tool with seals 35 and 37 on either side of the tangential cover 36. As in the embodiment of FIG. 2a, the inner partial bladders 38-41 have an extension along the central axis of the key tool of substantially cylindrical shape and the seal as the seals 35 and 37 on both sides of the tangential recovery 36 key edges are substantially aligned on generatrices of this substantially cylindrical shape.

In Figure 3b, which shows a detail of the interface between the keys 30 and 33 of the key tool of Figure 3a, there is shown a particular embodiment of a tangential overlap adjacent key edges as in the case of Figure 2b. The adjacent edges have a thinning 51 on the key 30 and a thinning 52 on the key 33 so that no extra thickness appears neither on the inner surface nor on the outer surface of the key tool. A seal 50 is disposed between the two thinning 51 and 52 as the seal 23 of the embodiment of Figure 2b.

In the embodiment of Figure 3b, the inner partial bladder 38 has two seals 48 and 49 on either side of the tangential covering 51, 52 and disposed on the inner surface of the key tool according to generatrices of its substantially cylindrical shape.

On the upper part of the partial partial bladder 38, partial inner bladder returns 57 and 55 are arranged which are connected with flaps 58 and 56 which are intended to come on seals 46 and 47 placed between the flap. of the partial partial bladder and the inner surface of an outer bladder 28.

In Figure 4a, there is shown an embodiment of a key tool with two keys 60 and 61. The key 61 has an angular extension around the central axis of the smaller key tooling than the angular extension of the key 60. The tangential overlap of the adjacent edges is based on the thinning technique described in FIGS. 2a and 2b. Thus the key 61 has thinning 66 and 67 on both sides which are arranged on the side of the outer surface of the key tool, while the key 60 has thinning 64 and 657 on its two edges which are arranged on the side of the inner surface of the key tool. Elongated seals 63 and 62 are disposed between the homologous thinnings of the tangential overlap edges as described above.

In Figure 4b, there is disposed a seal 68 disposed over the entire upper ring forming the upper edge of the key tool. The seal 68 is used to seal between the inner and outer bladders by their returns as has been described in Figures 2b and 3b.

In Figure 5, there is shown a schematic section of an inner partial bladder 70 according to the invention by a radial plane containing the central axis 71 of the key tool. Key tooling has not been shown to simplify the drawing. Dashed the position of the outer bladder 72 which, in the invention realize the complete entourage of the key tool beyond its outer surface. The key tool is of course disposed in the volume between the inner partial bladder 70 and the outer bladder 72.

The inner partial bladder 70 has a complex generating line 73 rather parallel to the central axis 71 of the key tool. On the cylindrical shape thus generated, is connected an internal partial bladder return 74 which is then extended by a tab 75. The partial partial bladder return 74 is intended to be applied on the upper edge of the key tool (see Figures 4a and 4b) through a seal 76 (similar to seal 68, Figure 4b). It finally carries a lug 75 which returns parallel to the inner surface of the outer bladder 72 to which it is connected by a seal 77 on a portion 78 configured for this purpose.

Preferably, the key tool of the invention contains from three to five keys using tangential overlap edges as described above.

Removable attachment of the adjacent keys is achieved by tangential bolting internally of the key edge structure. In particular, at positions along the tangential liner aligned at predetermined levels along the central axis of the key tool, tangential bores are made on the inner surface or the outer surface, through each of which a tapping smaller diameter crosses the two edges opposite two adjacent keys. A bolt is then introduced into the tangential drilling and is screwed through the tapping common to both keys, so that they are then integral with each other. Upon disassembly, the bolt head is accessible to the operator who can then release the bolt and disconnect the two adjacent keys. By repeating the same bolt and tapping assembly on various levels along the central axis of the key tool and on each tangential covering of each pair of adjacent keys, it is thus possible to perform a removable connection of the keys which can be thus easily secured and disengaged. Of course, a stud system traversing a tangential bore of the same axis for the two adjacent wrench edges and tightened with nuts on the two threaded ends of the stud is also provided.

In another embodiment, each key, or the keys that must be moved during the handling of the key tool, is provided with a means of attachment to a complex system of automatic connection and manipulation of keys. Such an automatic connection and key manipulation system may comprise one or more robotic arms which are controlled so as to maintain the connection between the keys on their tangential overlaps during the duration of the operations of use of the key tool such as the compaction of the folds of the preform in technical fabric, and as the polymerization during the impregnation of the preform compacted and folded by a thermoformable resin. The robotic arm or arms are also controlled to separate the keys of the key tool after each of its uses and to drive the mobilized key to a specific rest position.

The solution provided by the new technique of tangential overlapping of the adjacent edges of keys is to postpone the sealing of the key tool on a face parallel to the lines of the mold in order to have a sealing by crushing and not by lateral contact with a Bladder placement management before either:

by at least one internal partial bladder associated with a bladder external to the tooling;

- by a bladder external to the tooling only.

According to a first concept of application of the key tool, the invention consists in the application of at least one internal partial bladder associated with a bladder external to the tooling so as to: - make a flat join between keys to have a front interface;

- integrate a seal between keys to achieve at least compaction without internal bladder. Indeed, the compacting applies an intermediate compression during the manufacture of the panel for packing the folds of the fabric preform previously installed in the key tool;

performing at least one partial internal bladder covering at least one junction of two keys instead of an internal peripheral bladder covering all the keys.

The advantages of the first application concept of the key tools of the invention are mainly that:

- The front interface is more reliable thanks to a support, for the positioning between two keys that the interface obtained by a connection by radial returns of the keys;

- It reduces the risk of improper placement of the bladder, and therefore it limits the risk of rupture during the polymerization;

- It facilitates the removal of keys during the demolding operation;

- the time required to pass within the key tool for the operators is limited, so that the health and safety conditions of the staff at work are greatly improved.

According to a second application concept of the key tool, the invention consists in applying a single external bladder to the tooling only, so as to:

- make a flat join between keys to have a front interface;

- integrating a seal between keys to achieve compaction and polymerization without internal bladder Indeed, the compaction applies an intermediate compression during the manufacture of the panel for packing folds of preform fabric previously installed in the tooling keys ;

- Ensure a definition of the specific seal allowing a continuity of tightness of the keys without having to achieve sealing by the internal tooling.

The advantages of the second application concept of the key tools of the invention are mainly that: - the front interface is more reliable (free support) for the positioning between two keys that a connection by radial returns of the keys;

- the risks of bad placement of the internal bladder are eliminated;

- It facilitates the removal of keys during the demolding operation;

the time necessary to pass inside the mold for the operators is eliminated.

As has already been mentioned above, the technique of the invention can indifferently be implemented inside or outside the key tool. Thus, if solutions with one or more partial inner or inner bladders have been described, then only one outer or outer bladder is provided, but completely surrounds the outer surface of the key tool. It is intended to reverse the partial bladders by placing them outside the key tool, becoming external or external partial bladders and then there is disposed a complete inner or inner bladder.

Similarly, the key connection means can be indifferently disposed on the inner surface or on the outer surface of the key tool.

The tool of the invention is used for the production of a composite panel, in particular for an aircraft engine nacelle. The panel has a symmetry of revolution which, during manufacture is determined by the central axis of the key tool. The composite panel comprises a preform in a technical textile such as carbon fiber, or kevlar, in the form of a weave which is then draped, folded, compacted and impregnated with resin using a key tool according to the previous description.

Claims

1. A key tool of the type having at least two keys having adjacent edges, the tool having a substantially cylindrical shape with a central axis, the adjacent edges being substantially parallel to the central axis, characterized in that the adjacent edges have overlaps tangential (12; 20, 21; 36; 51, 52) relative to the inner and / or outer surface of the key tool.

2. Key tool according to claim 1, characterized in that the tangential overlap of two adjacent edges of keys comprises a thinning (51) of a first edge of an inner side of the tool vis-à-vis thinning (52) a second edge of an outer side of the tool so that no extra thickness is introduced on the inner and / or outer surface of the key tool.

3. Key tool according to claim 1 or 2, characterized in that tangential overlapping portions of two adjacent edges cooperate with a seal (23; 50).

4. Key tool according to any one of the preceding claims, characterized in that at least one tangential overlap of adjacent edges of keys is covered by an inner and / or outer partial bladder (18; 38; 70), two joints sealing means (13, 14; 35, 37) substantially parallel to the central axis of the key tool being arranged on either side of said at least one tangential covering between the inner and / or outer partial bladder ( 18; 38) and the inner and / or outer surface of the key tool.

5. A key tool according to claim 4, characterized in that an inner or outer partial bladder (18; 38; 70) cooperates with an outer or inner bladder (28; 45; return (26; 55; 74) passing over the annular rim of the key tool and a tab contacting a seal (24; 46; 47; 77) on the facing surface; a counterpart (78) of said outer bladder, respectively inner (28; 45; 72).

6. Key tool according to claim 5, characterized in that a seal (68; 76) is disposed on an annular edge of the key tool so as to seal an inner partial bladder. or outside at its return (26; 55; 74) passing over the annular edge of the key tool.

7. Key tool according to any one of the preceding claims, characterized in that it cooperates with at least one inner partial bladder, respectively outer, and an outer full bladder, respectively inner.

8. Key tool according to any one of claims 1 to 6, characterized in that it cooperates with only a complete outer bladder, respectively inner.

9. Key tool according to any one of the preceding claims characterized in that keys are secured by tangential connection means to bolt or stud, and / or by a connection system and key manipulation.

10. Composite panel, especially for aircraft engine nacelle, having a symmetry of revolution, characterized in that it comprises a pleated draped preform, shaped, compacted and impregnated with resin using a key tool according to the invention. any preceding claim.