FR3047866A1 - CASE FOR AVIONIC EQUIPMENT - Google Patents

Abstract

The invention relates to a housing for avionic equipment of an aircraft comprising: - a bottom face (10) configured to include first mounting means of at least one electronic card, - a substantially parallel and opposite upper face (12) at the bottom face (10) and configured to comprise second mounting means of the at least one electronic card, and - two substantially parallel lateral faces (14) extending between the upper face (12) and the face base (10), the bottom face (10), the upper face (12) and the side faces (14) being formed from single pieces (20, 30, 40, 50, 60) and each having a profile, said parts having at most three different profiles.

Description

FIELD OF THE INVENTION The invention relates generally to the field of electronic equipment mounted in avionics bays, and more particularly to the packaging of such equipment.

BACKGROUND

An electronic equipment intended to be mounted in an avionics bay includes, in an often metal packaging also known as a package or "packaging", a set of heat dissipating electronic cards.

An avionics bay is a mechanical structure of "shelf" type generally placed under the cockpit of the aircraft and designed to accommodate the various electronic equipment intended to operate the aircraft and its services via electric adaptation chairs and mechanical. The avionics bay makes it possible to mechanically and electrically connect one or more electrical equipment removably to the various on-board networks, communication networks, power distribution networks, control networks, etc. of the aircraft.

The size and shape of the avionics equipment housings inserted in the avionics bay is dictated by the ARINC 600 standard. The evolution of current aircraft has the effect of subjecting these avionics equipment cases to increasingly severe thermal and vibration environments. . Electronic cards dissipate more and more heat in a smaller and smaller volume. At the same time, aircraft manufacturers are seeking to significantly reduce the weight of the casings, while respecting the criteria imposed by the ARINC 600 standard.

It is therefore sought to evacuate more efficiently the power dissipated by the electronic cards in the same volume.

It has already been proposed to make cases for avionic equipment in a thermosetting composite material. However, it turns out that the manufacturing process of this type of housing is difficult to apply on an industrial scale. Indeed, the different parts to be made are of small size, so that the manufacturing tolerance is low and therefore drastically increases their cost of manufacture. The mass gain associated with this choice of material is not sufficient to offset the increase in the cost of the housing.

SUMMARY OF THE INVENTION

An objective of the invention is therefore to propose a case for avionic equipment meeting the requirements of the ARINC 600 standard, that is to say, to be fixed on an electric and mechanical adaptation chair conforming to the ARINC 600 standard, which can be manufactured on an industrial scale at a lower cost while having a reduced mass and an equivalent size compared to current avionics equipment housings, the housing must also be able to withstand severe thermal and vibratory environments and to respect the electromagnetic continuity required to protect the electronic card (s) it receives as well as the external equipment.

For this, the invention proposes a case for avionic equipment of an aircraft comprising: - a bottom face configured to include first mounting means of at least one electronic card, - an upper face substantially parallel and opposite to the face bottom and configured to include second mounting means of the at least one electronic card, and - two substantially parallel lateral faces, extending between the upper face and the bottom face.

The bottom face, the upper face and the lateral faces are formed from single pieces and each having a profile and the parts forming the bottom face, the upper face and the lateral faces have at most three different profiles. .

In one embodiment, the lateral faces are each formed of two lateral pieces having an elongated profile, while the bottom face and the upper face are respectively formed by two end pieces each having a fixing profile.

Some preferred but non-limiting features of this embodiment of the housing described above are the following, taken individually or in combination: the elongated profile of each lateral piece has a planar face extending between the upper face and the face of bottom and comprising at its free ends a recess configured to connect said side piece to the end pieces, - the attachment profile of the end pieces each comprise two planar faces, extending in the same plane and separated by a groove central, and two recessed walls extending on either side of said planar faces, said recessed walls being configured to be connected to one of the side pieces, respectively; the housing further comprises a separating piece, extending between the side pieces, and configured to separate an internal volume of the housing in two spacers The parts are made of at least one of the following group of materials: a composite material comprising a fibrous reinforcement densified by a polymer matrix or a metal alloy having a thermal conductivity greater than or equal to 140 W / m / K all or part of the parts are made of a composite material and furthermore comprise, on an inner face and / or on an external face, an electrically conductive coating configured to block electromagnetic waves, said coating possibly comprising a metallic mesh, metal foils and / or a metal fabric, - all or part of the parts are made of a composite material comprising a matrix-reinforced fibrous reinforcement and are obtained by stamping or by draping folds on a preform, and / or - the upper face and the bottom face are symmetrical.

In a second embodiment, the lateral faces each comprise an upper portion and a lower portion, the upper face and the upper portion of the lateral faces being formed in at least a first piece having a U-shaped profile while the bottom face and the lower portion of the lateral faces are formed in at least one second piece having a U-shaped profile, the profiles and U of the first piece and the second piece each comprising a base and two lateral flanks extending from ends of the base .

Some preferred but non-limiting characteristics of the housing described above are the following, taken individually or in combination: the U-shaped profiles of the first part and the second part are identical, a first one of the lateral flanks of each of the profiles in U has a recess at a free end so as to allow interlocking of the first lateral flanks with the second lateral flanks of said U-shaped profiles, the housing further comprises a third part and a fourth part each having a fastening profile respectively connected at the base of the U-profile of the first piece and the second piece, said fixing profiles being configured to fix the first mounting means and the second mounting means, respectively; each a planar face and a first and a second groove grooves extending from and other of the planar face, the third piece and the fourth piece being connected to the first piece and the second piece through the first groove and the second groove, respectively, the housing comprises at least two housing subassemblies each formed by a first assembled part with a second part, the housing subassemblies being fastened in pairs by assembling the lateral flanks of the U-sections of the first part and the second part,

BRIEF DESCRIPTION OF THE DRAWINGS Other features, objects and advantages of the present invention will appear better on reading the detailed description which follows, and with reference to the appended drawings given by way of non-limiting examples and in which:

FIG. 1 is an exploded perspective view of an exemplary embodiment of an avionic equipment box according to a first embodiment,

FIG. 2 is a sectional view of the avionic equipment box of FIG. 1,

FIG. 3a is a sectional view of a U-profile of the avionic equipment box of FIG. 1,

FIG. 3b is a sectional view of a fastening profile of the avionic equipment box of FIG. 1,

FIG. 4 is an exploded perspective view of an exemplary embodiment of an avionic equipment box according to a second embodiment,

FIG. 5 is a sectional view of the avionic equipment box of FIG. 4,

FIG. 6a is a sectional view of an elongate profile of the avionics equipment case of FIG. 4,

FIG. 6b is a sectional view of an end profile of the avionics equipment case of FIG. 4 and

FIG. 6c is a sectional view of a separation part of the avionic equipment box of FIG. 4,

DETAILED DESCRIPTION OF AN EMBODIMENT

A box 1 for avionic equipment of an aircraft comprises: a bottom face 10 configured to comprise first mounting means of at least one electronic card, an upper face 12, substantially parallel and opposite to the bottom face and configured to include second mounting means of the at least one electronic card, and - two lateral faces 14, extending between the upper face 12 and the bottom face 10. The lateral faces 14 each comprise an upper portion, adjacent to the upper face 12, and a lower portion, adjacent to the bottom face 10.

The bottom face 10, the upper face 12 and the lateral faces 14 are formed of integral parts (that is to say, one-piece, or integrally formed) and each having a profile. By profile, here will be understood the section of the part in a direction perpendicular to its inner surface.

In the usual way, the housing 1 houses several electronic cards and as many first and second mounting means of said electronic cards. These first and second mounting means are generally identical and may comprise, in a manner known per se, cardlock type slide-holder supports (not visible in the figures).

The housing 1 is configured to be fixed, for example by screwing, on an electric and mechanical adapter chair, preferably in accordance with the ARINC 600 standard. It comprises for this purpose a rear face 18 comprising inverters configured to be connected with electrical connectors formed in a plate of the chair. The rear face 18 extends between the bottom face 10 and the upper face 12 on the one hand and between the lateral faces 14 on the other. The housing 1 also comprises a front face 16 opposite the rear face 18 and substantially parallel thereto.

Typically, the casing 1 may have a length (dimension between the front face 16 and the rear face 18) outside the doghouse of 319 mm (379 mm with doghouse), a height (dimension between the bottom face 10 and the upper face 12). 193 mm and a width (dimension between the side faces 14) equal to 248 mm. By doghouse, here will be understood the advance (optional) of the front face 16 of the housing 1 configured to move the front face 16 beyond the fixing screws of the housing 1 to the chair.

In order to facilitate the production of the housing 1 and thus to reduce its production costs, the parts forming the bottom face 10, the upper face 12 and the lateral faces 14 have at most three different profiles.

It is then possible to produce the casing 1 of composite material having a fiber reinforcement densified by a polymer matrix, or alternatively metal alloy, in a simple, fast, inexpensive and easily achievable on an industrial scale. Indeed, it is sufficient to perform, at the chain, the parts forming the casing 1 and to assemble them to obtain a casing 1 for avionics equipment having a low mass, the dimensions and shape of which comply with the ARINC 600 standard and which in addition, it is able to resist and protect electronic boards in severe temperature and vibration environments.

The composite material may in particular comprise a fibrous reinforcement comprising long fibers, such as carbon fibers, while the polymer matrix may comprise a thermoplastic material such as polyphenylene sulphide PPS, polyetheretherketone PEEK, a polyamide and / or or polycarbonate, or alternatively a thermosetting material such as an epoxy resin. The metal alloy may comprise any type of alloy having a thermal conductivity greater than or equal to 140 W / m / K, such as a type 6061 aluminum alloy (T6 state) or a copper alloy.

In a first embodiment illustrated in Figures 1 to 3b, the parts forming the bottom face 10, the upper face 12 and the side faces 14 have exactly two different profiles.

More specifically, in this embodiment, the housing 1 comprises two sub-assemblies 2, 3 configured to each accommodate an LRU (acronym for Line-Replaceable Unit, for an on-line replacement unit, that is to say one unit comprising a series of electronic cards).

For each subassembly 2, 3, an upper part 20 having a U-shaped profile forms the upper face 12 and the upper portion of the lateral faces 14 while a lower part 25 also having a U-shaped profile forms the bottom face 10 and the lower portion of the lateral faces 14. The profiles and U of these parts each comprise a base 21 and two lateral flanks 22 extending from ends of the base 21. The lateral flanks 22 are substantially perpendicular to the base 21.

In one embodiment, the upper part 20 and the lower part 25 are identical, which reduces the manufacturing cost of the housing 1. In this case, it is indeed possible to pool the machines for the production of these parts .

As a variant, the upper part 20 and the lower part 25 may have distinct U-shaped profiles, and in particular profiles whose height of the lateral flanks 22 is different.

The upper part 20 and the lower part 25 can be assembled by connecting the free end of the lateral flanks 22 of their respective U-profile by mechanical assembly (for example by screwing, snapping, riveting), gluing or welding (when the constituent material parts allow it). Note that in assembled configuration, the bases 21 of the U-shaped profiles are then placed opposite one another and each define one of the bottom face 10 and the upper face 12 of the housing 1, while the lateral flanks 22 form two by two its lateral faces 14.

For example, one of the lateral flanks 22 of each of the U-shaped profiles may have a recess 23 at its free end (that is to say opposite to its base 21). In this way, when the upper part 20 and the lower part 25 are assembled, the free end of each side flank having a recess 23 is housed against the outer face (or against the inner face) of the free end 24 of the side flank devoid of recess 23 and extending opposite. The pieces are then brought closer until their respective recess 23 comes to a stop.

Where appropriate, as shown in Figures 2 and 3 attached, one of the side flanks 14 may have a height slightly larger than the other, to facilitate assembly.

Each subassembly 2, 3 further comprises a first fastener 30 fixed against the base 21 of the U-profile of the lower part 25 and a second fastener 35 fixed against the base 21 of the U-profile of the upper part. 20. The first fastener 30 and the second fastener 35 are configured to attach the first mounting means and the second mounting means, respectively.

In one embodiment, the first fastener 30 and the second lower part 25 are identical, which reduces the manufacturing cost of the housing 1 by pooling the machines for the production of these parts.

Here, each fixing piece 30, 35 comprises a flat face 31 and two grooves 32 extending on either side of the flat face 31. The grooves 32 thus allow the attachment of mounting means of the electronic cards of the support type. slide holder with lock (such as a Cardlock).

Each fixing piece 30, 35 can then be connected to the upper or lower piece associated with its grooves 32.

Each subassembly 2, 3 of the housing 1 is configured to house an LRU. In order to obtain a housing 1 housing two LRUs, it is sufficient to assemble side by side two subassemblies 2, 3 according to the first embodiment and preferably having an identical length and height. Typically, the subassemblies 2, 3 can be fixed along their lateral faces 14 by mechanical assembly (for example by screwing, snapping, riveting), bonding or welding (when the constituent material of the parts allows it).

It will of course be understood that a larger number of subassemblies 2, 3 can be assembled, so as to accommodate a larger number of LRUs in the housing 1.

In a second embodiment illustrated in Figures 4 to 6c, the parts forming the bottom face 10, the upper face 12 and the side faces 14 have between two and three different profiles.

In this embodiment, the housing 1 may comprise a separation piece 40 extending between the side faces 14 to form two subassemblies 2, 3 configured to each house an LRU.

Here, the housing 1 comprises two lateral pieces 50, each having an elongated profile and configured to form the side faces 14 of the housing 1, and two end pieces 60 each having a fixing profile and configured to form the bottom face 10 and the upper face 12. Each end piece 60 is configured to attach one of the first and second mounting means.

In one embodiment, the side pieces 50 are identical, which makes it possible to reduce the manufacturing cost of the case 1. As a variant, the lateral pieces 50 may have distinct elongate profiles, and in particular profiles whose free ends are different. .

Similarly, the end pieces 60 may be identical or have separate fastening profiles to accommodate different mounting means.

Each lateral piece 50 may have a flat face 52 extending between the upper face 12 and the bottom face 10 of the casing 1 and comprise, at its free ends, a recess 54 configured to connect the lateral piece 50 to the parts of the casing. end 60. Here, the recess is double and forms a stair comprising a first step 54a (or elbow) configured to be fixed on the associated end piece 60 and a second step 54b connecting the first step 54a and the flat face 52 and thus making it possible to offset the mounting means with respect to said plane face 52.

The fastening profiles of the end pieces 60 each comprise at least two plane faces 62 extending in the same plane and separated by a central groove 64 and two recessed walls 66 extending on either side of said planar faces. 62. The fastening profiles therefore have a substantially corrugated shape.

The bottom of the central groove 64 and the recessed walls 66 of the fastening profiles extend in the same plane. The central groove 64 is configured to allow (optional) attachment of the separating piece 40. Each recessed wall 66 is arranged to cooperate with a recess 54 (for example with the first step 54a) of the associated lateral piece 50 to form a groove 68 adapted to allow, in combination with the central groove 64, the attachment of one of the mounting means on the corresponding end piece 60. For this, one of the surfaces of the first step 54a of the recess 54 may for example be fixed on the surface facing the recessed wall 66 of the end piece 60.

The grooves 68 and the central groove 64 may in particular be configured to fix a cardlock-type slide holder support.

Alternatively, the fixing profiles may comprise, in place of each of the recessed walls 66, an additional groove and an additional wall extending in the extension of the flat face 22, the additional groove being closer to the central groove 64 than the additional wall. The additional groove is then configured to allow, in combination with the central groove 64, the fixing of one of the mounting means on the corresponding end wall, while the additional wall is adapted to be fixed on the recess 54 ( for example, the first step 54a) of the associated lateral piece 50.

The separating piece 40 may comprise a substantially flat plate 42 comprising, at its free edges, connecting means 44 to the end pieces 60. Typically, when the end pieces 60 comprise a central groove 64, the means connection 44 can be obtained by folding the free edges of the plate 42 so as to form a 90 ° elbow at each of said edges. The bent edges 44 of the plate 42 then extend in a direction substantially parallel to that of the bottom of the central groove 64, thus allowing easy fixing of said edges, for example by gluing or welding. The angled edges 44 may be oriented towards the same lateral face 14 of the casing 1, or alternatively (as illustrated in FIG. 5) towards opposite lateral faces 14.

Alternatively, in the case where the housing 1 is devoid of separation part 40, the fastening profiles of the end pieces 60 may comprise only one flat face 62 and the recessed walls 66 (or, if appropriate, the additional groove and the additional wall) extending on either side of the flat face 62.

It will be noted that whatever the embodiment, the parts 20, 30, 40, 50, 60 have a substantially identical profile over a majority of their length.

In order to obtain a casing 1 housing two LRUs, it is then sufficient to assemble two lateral pieces 50 with two end pieces 60 and to fix between the end pieces 60 a separating piece 40 so that the separating piece 40 extends substantially parallel to the side pieces 50. The separating piece 40 thus delimits two distinct and separate spaces of the housing 1.

Of course, it will be understood that a larger number of LRUs can be housed in the same housing 1 comprising two lateral parts 50, by using several separating pieces 40 and end pieces 60 whose fastening profiles have a greater number planar faces 62 and central grooves 64. Typically, for a housing 1 housing three LRU, the fixing profiles may comprise three flat faces 62 separated in pairs by two central grooves 64, each central groove 64 being configured to receive a means connecting a separating part 40, and recessed walls 66 extending on either side of the set of flat faces 62, at the side faces 14. More generally, a housing 1 configured to house n LRU may comprise two lateral pieces 50 and two end pieces 60 whose attachment profiles comprise n planar faces separated in pairs by n-1 groove s 64, each central groove 64 being configured to receive a connection means 44 of a separating part 40, and recessed walls 66 extending on either side of the flat faces 62.

The housings 1 according to the first and second embodiments described above can be obtained by stamping or folding plates made of the desired material for each of the parts 20, 30, 40, 50, 60.

Typically, in the case of a casing 1 made of composite material comprising a fiber reinforcement densified by a polymer matrix, preferably a thermoplastic matrix, the parts 20, 30, 40, 50, 60 can be obtained by stamping or by pleat draping. on a preform.

In the case of stamping, a prepreg fabric may for example be consolidated in a first step. For this, the different plies of the prepreg fabric are placed in the desired orientation and then heated and pressed in order to move from a stack of independent monoplants to a flat laminate devoid of voids interfaces.

In a second step, the laminate can be stamped in a conventional manner, by heating the laminate to a temperature greater than or equal to the melting temperature of the polymer constituting the matrix and then by hot stamping the laminate thus heated between a punch and a stamping die. In particular, reference may be made to document FR 2 922 276 for details on an example of a process for stamping a part made of composite material.

The parts 20, 30, 40, 50, 60 are then cut away in order to put them to length and realize, if necessary, the doghouse.

During the trimming step, the upper face 12 and the bottom face 10 of the housings 1 may further be machined to form ventilation holes 15. For example, two ventilation holes 15 having a substantially rectangular contour may each of these faces 10, 12 is formed. Thus, in the case of the first embodiment, the base 21 of the U-shaped profiles of the upper and lower parts 25 of each of the sub-assemblies 2, 3 can be machined before assembling said parts 20, 25 so as to form a ventilation hole 15. In the case of the second embodiment, a ventilation hole 15 may be machined in the flat faces 62 of each end piece 60.

A metal grid can then be fixed in the ventilation holes 15 thus formed.

Note that the size and position of ventilation holes 15 is conventional for a case 1 for avionics equipment. It is the same for the metal grid.

Optionally, the lateral faces 14 of the casing 1 may comprise stiffeners in order to structurally reinforce the casing 1. These stiffeners may be attached and fixed on the lateral faces 14, for example by gluing or welding, or alternatively be made by stamping the faces lateral 14 (or where appropriate, during the step of stamping the side faces 14, using a punch and a stamping die adapted).

Optionally also, some of the parts 20, 30, 40 may be recessed to reduce the mass of the housing 1. Typically, through recesses can be made in the separation part 40 of the housing 1 according to the second embodiment or in the lateral flanks 22 of U-shaped profiles which are fixed against each other during the assembly of two subassemblies 2, 3 according to the first embodiment.

Once the pieces 20, 30, 40, 50, 60 have been made, it is then sufficient to assemble them so as to obtain the casing 1. For this purpose, the different parts 20, 30, 40, 50, 60 of the casing 1 can be assembled, as indicated above, by mechanical assembly (for example by screwing, snapping, riveting), gluing or welding (when the constituent material of the parts allows it).

A front face 16 and a rear face 18 can then be attached and fixed on the casing 1 thus assembled, in particular by mechanical fastening (using riveted or screwed nuts for example) on the lateral faces 14 (axially, c that is to say on the edge of the lateral faces 14, or laterally, that is to say perpendicularly to the side faces 14). For this purpose, the front face 16 and the rear face 18 comprise tabs 17 in order to facilitate this mechanical fixing.

The front face 16 and / or the rear face 18 may comprise a composite material reinforced by a polymer matrix. Typically, the fibrous reinforcement may comprise long fibers such as carbon fibers, while the polymer matrix may comprise a thermoplastic material such as polyphenylene sulphide PPS, polyetheretherketone PEEK, a polyamide and / or polycarbonate, or alternatively a thermosetting material such as an epoxy resin.

As a variant, the front face 16 and / or the rear face 18 may be made of a metal alloy having a thermal conductivity greater than or equal to 140 W / m / K, such as an aluminum alloy of the 6061 type (T6 state ) or a copper alloy.

The front face 16 and the rear face 18 can be obtained by stamping, in a manner similar to that described for the other faces of the housing 1.

Alternatively, the front face 16 being lightly loaded, it can be performed by injection. Similarly, the weakly charged areas of the rear face 18 can be made by injection while the loaded faces (areas for fixing an inverter) can be obtained by stamping and then assembled with the injected areas, for example by mechanical assembly.

Finally, when the parts 20, 30, 40, 50, 60 are made of a composite material, they also comprise, on an inner face (facing the electronic boards) and / or on an outer face, an electrically conductive coating configured to block electromagnetic waves. Preferably, the parts 20, 30, 40, 50, 60 comprise on their inner face and on their outer face such a conductive coating.

The conductive coating may comprise in particular a metal mesh, metal foils and / or a metal fabric, or be obtained by metallization of the walls. The conductive coating may in particular be made of a metal alloy preferably having a thermal conductivity greater than or equal to 140 W / m / K, such as a 6061 T6 type aluminum alloy or a copper alloy.

The bottom face 10, the upper face 12 and the side faces 14 of the housing 1, and if appropriate the front face 16 and the rear face 18, are preferably made of the same material.

Claims (8)

1. Box (1) for avionic equipment of an aircraft comprising: - a bottom face (10) configured to include first mounting means of at least one electronic card, - a substantially parallel and opposite upper face (12) at the bottom face (10) and configured to comprise second mounting means of the at least one electronic card, and - two substantially parallel lateral faces (14) extending between the upper face (12) and the face base (10), the bottom face (10), the upper face (12) and the side faces (14) being formed from single pieces (20, 30, 40, 50, 60) and each having a profile, the housing (1) being characterized in that the parts (20, 30, 40, 50, 60) forming the bottom face (10), the upper face (12) and the side faces (14) have at most three different profiles the side faces (14) being each formed of two side pieces (50) present an elongate profile, while the bottom face (10) and the upper face (12) are respectively formed by two end pieces (60) each having a fixing profile. Housing (1) according to claim 1, wherein the elongate profile of each side piece (50) has a flat face (52) extending between the upper face (12) and the bottom face (10) and comprising at its free ends a recess (54) configured connect said side piece (50) to the end pieces (60). 3. Housing (1) according to one of claims 1 or 2, wherein the fastening profile of the end pieces (60) each comprise two planar faces (62), extending in the same plane and separated by a central groove (64), and two recessed walls (66) extending on either side of said flat faces (62), said recessed walls (66) being configured to be connected to one of the side pieces ( 50), respectively. 4. Housing (1) according to one of claims 1 to 3, further comprising a separating piece (40) extending between the side pieces (50), and configured to separate an internal volume of the housing (1) in two distinct spaces. 5. Housing (1) according to one of claims 1 to 4, wherein the parts (20, 30, 40, 50, 60) are made in at least one of the following group of materials: a composite material comprising a fibrous reinforcement densified by a polymer matrix or metal alloy having a thermal conductivity greater than or equal to 140 W / m / K. 6. Housing (1) according to one of claims 1 to 5, wherein all or part of the parts (20, 30, 40, 50, 60) are made of a composite material and further comprise, on an inner face and or on an outer face, an electrically conductive coating configured to block electromagnetic waves, said coating may comprise a metal mesh, metal foils and / or a metal fabric. 7. Housing (1) according to one of claims 5 or 6, wherein all or part of the parts (20, 30, 40, 50, 60) are made of a composite material comprising a reinforcing fiber reinforced matrix and are obtained by stamping or draping folds on a preform. 8. Housing (1) according to one of claims 1 to 7, wherein the upper face (12) and the bottom face (10) are symmetrical.