Method for protecting an electronic housing and associated electronic housing, measurement system and aircraft

Abstract

The invention relates to a method for protecting an electronic housing, comprising the steps of: - injecting at least one liquid or semi-liquid filling product into the housing (1) via at least one first injection opening provided in one of the walls of the housing; - stopping injection of the product when the product is present in at least one portion of at least one first opening and / or of at least one second opening provided in one of the walls of the housing; and - curing the product. The invention also relates to a corresponding housing, measurement system and aircraft.

Description

[0001] METHOD FOR PROTECTING AN ELECTRONIC UNIT, ELECTRONIC UNIT, MEASURING SYSTEM AND ASSOCIATED AIRCRAFT

[0002] The invention relates to a method for protecting an electronic housing.

[0003] The invention also relates to an electronic box thus protected.

[0004] The invention also relates to a tire pressure measurement system comprising such an electronic box. The invention also relates to an aircraft equipped with such a measurement system.

[0005] BACKGROUND OF THE INVENTION

[0006] In the aeronautical field, it is known to measure the tire pressure of the landing gear of an aircraft using one or more pressure measurement sensors. The data they generate are supplied to a computer remote from the landing gear via at least one electronic box, communication between the pressure sensors and the box taking place by radio link.

[0007] Such a box is generally arranged in a sensitive area of ​​the aircraft, such as, for example, at the level of one of the holds provided in the fuselage of the aircraft to receive at least one of the landing gears.

[0008] Regardless of its position in the aircraft, such a box is subject to very high environmental and mechanical constraints.

[0009] Consequently, such a box must meet numerous constraints (lightning resistance, explosion resistance, etc.) in order to protect the aircraft in the event of a failure. In addition to all this, the radio link between the pressure sensors and the box must not be disrupted by the presence of one or more protections to meet such constraints. This implies, when designing the box, respecting significant electrical insulation distances and dielectric levels between the various electronic elements of the box by using generously sized connectors and / or mechanical parts.

[0010] The size of the case is greatly increased. This also means that the case must comply with explosion resistance constraints.

[0011] To this end, a first technique is to use explosion-proof enclosures. An explosion-proof enclosure is designed to withstand an explosion occurring inside it and to prevent the ignition of combustible materials surrounding the enclosure. Explosion-proof enclosures must also ensure an external temperature (skin temperature) lower than that which is sufficient to ignite the surrounding materials.

[0012] However, such boxes are very bulky.

[0013] A second technique is to protect the housing by a purge system providing a protective gas around and / or in the housing to limit the presence of flammable gases around and / or in the housing.

[0014] However, purge systems are relatively complex and involve the addition of a gas supply source.

[0015] One could imagine using intrinsically safe electrical circuits (limiting the energy used so that the circuit cannot provide enough energy to trigger a fire or an explosion).

[0016] Unfortunately, this technique is difficult to apply to the aeronautical field, given that the box is directly powered by the aircraft's electrical network. OBJECT OF THE INVENTION

[0017] The invention aims in particular to respond at least in part to the aforementioned problems.

[0018] SUMMARY OF THE INVENTION

[0019] To this end, the invention provides a method for protecting an electronic housing comprising the steps of: injecting at least one liquid or semi-liquid filling product into the electronic housing via at least one first orifice provided in one of the walls of the housing, stopping the injection of the product when the first orifice is at least partially filled with the product and, if the housing comprises one or more additional orifices provided in one or more walls of the housing, when the additional orifice(s) are also partially filled with the product, hardening the product.

[0020] Thus, the product fills most of the gaps present in the housing (or even all of the gaps) and also helps to limit or even eliminate the presence of air bubbles in the housing.

[0021] This prevents the presence of gas inside the housing, gas which could potentially ignite when using the housing in the presence of a flame or spark.

[0022] Therefore, the invention makes it possible to effectively protect an electronic box and thus better preserve its performance.

[0023] Furthermore, the invention proves advantageously simple to implement. In addition, the invention makes it possible to obtain a relatively compact protected housing.

[0024] It is noted that the housing thus protected is of simple construction. It is also compact. It thus meets the constraints of electrical insulation, lightning resistance and resistance to explosive atmospheres (in particular in a confined environment). Advantageously, even if the housing were to explode, the hardened product would also make it possible to greatly limit or even eliminate a risk of material being projected into the environment of the housing. In addition, the invention makes it possible to significantly reduce insulation distances and creepage lines inside the electronic housing compared with an electronic housing of the prior art.

[0025] A "liquid" or "semi-liquid" product is any product that is fluid enough to move inside the housing when injected. The product can be a resin or a foam. It should also be noted that the product must have hardening properties once injected into the housing.

[0026] Optionally, the method includes an additional step of removing one of the walls of the housing once the product has hardened to replace it with a wall making it possible to define an air gap inside the housing between said wall and the hardened product.

[0027] Optionally the filler is a resin and / or a foam.

[0028] Optionally the resin is an elastomer and / or silicone and / or epoxy resin.

[0029] Optionally the resin is an RTV resin.

[0030] Optionally, the filling product is composed of at least two different by-products.

[0031] Optionally, the process includes a step of preliminary degassing of the resin before its injection into the housing. Optionally, the product is hardened by heating the housing.

[0032] The invention also relates to an electronic housing comprising walls jointly defining a housing, at least one of the walls being pierced with at least one additional orifice, the housing being furthermore filled at least in part with a filling product.

[0033] Optionally, the housing comprises a substrate on which at least one antenna is mounted, the substrate being mounted on a wall of the housing such that the antenna faces towards said wall.

[0034] Optionally, the housing comprises at least one sealing element compressed between the substrate and the wall carrying the substrate, the sealing element externally surrounding the antenna.

[0035] The invention also relates to a tire pressure measuring system comprising a housing as mentioned above. The invention also relates to an aircraft equipped with a measuring system as mentioned above.

[0036] Other characteristics and advantages of the invention will emerge upon reading the following description of a particular and non-limiting implementation of the invention.

[0037] BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Reference will be made to the attached drawings, among which: [Fig. 1] Figure 1 schematically represents a first step of a method of protecting a housing according to a particular implementation of the invention;

[0039] [Fig. 2] Figure 2 schematically represents a second stage following the first stage shown schematically in Figure 1;

[0040] [Fig. 3] Figure 3 schematically represents the end of the second stage shown in Figure 2;

[0041] [Fig. 4] Figure 4 schematically represents a subsequent stage following the second stage shown schematically in Figure 2;

[0042] [Fig. 5] Figure 5 is a rear view of an electronic housing protected by the method whose steps are shown diagrammatically in Figures 1 to 4;

[0043] [Fig. 6] Figure 6 is a front view of the electronics housing shown in Figure 5;

[0044] [Fig. 7] Figure 7 is a schematic view of an aircraft including the electronic box shown in Figure 5;

[0045] [Fig. 8] Figure 8 is a side view of a bottom cover of the housing shown in Figure 1;

[0046] [Fig. 9] Figure 9 is a side view of a final bottom cover of the housing shown in Figure 4.

[0047] DETAILED DESCRIPTION OF THE INVENTION

[0048] With reference to figures 1 to 6 and to figures 8 and 9, a method of protecting an electronic housing 1, according to a particular implementation of the invention, will be described.

[0049] During a first step, shown diagrammatically in Figure 1, the housing 1 is first assembled. However, at least one of the parts forming the housing 1 is then a temporary part.

[0050] Said temporary part is thus intended to be used only during the process of protecting the housing 1 and then to be removed from the housing at the end of the various stages of said process. When using the housing 1, the temporary part is therefore no longer present.

[0051] At the end of this first stage, the housing 1 comprises a box 2 having two main faces connected by lateral sides.

[0052] For example, the box 2 is in three parts and comprises a casing 3 on which a first cover (or upper cover 4) is mounted on the top and a second cover (or lower cover 5) is mounted on the bottom.

[0053] In this way, the casing 3 forms the lateral sides of the box 2, the upper cover 4 the upper main face of the box 2 and the lower cover 5 the lower main face of the box 2.

[0054] The casing 3 is for example made of a metallic material. The casing 3 is for example shaped as a closed frame. The frame is formed of a succession of walls and for example is formed of at least four walls. In the present case, the casing 3 has four walls parallel two by two. The casing 3 here externally delimits a square.

[0055] The lower cover 5 is preferably a temporary part. It is therefore only used during the protection process and will therefore not belong to the housing 1 when it is put into operation. The lower cover 5 is generally shaped as a plate. The lower cover 5 rests on the underside of the frame formed by the casing 3 so as to close the casing 3 at the bottom. The upper cover 4 is generally shaped as a plate. The upper cover 4 rests on the top of the frame formed by the casing 3 so as to close the casing 3 at the top. The upper cover 4 is optionally made of a material allowing the passage of radio waves through it in order to allow communication by radio waves between the inside of the housing 1 and the outside of the housing 1. The upper cover 4 is for example made of plastic.

[0056] The covers 4, 5 are for example screwed, glued, etc. onto the casing 3.

[0057] Box 2 thus defined is generally shaped like a rectangular parallelepiped.

[0058] The box 2 thus defined is hollow and therefore internally delimits a housing 6.

[0059] Inside this housing 6 is housed at least one substrate carrying at least one electronic element. The substrates are fixed to the box 2 for example by screwing, by gluing, etc.

[0060] For example, the substrate is a printed circuit board. The electronic element is directly etched onto at least one of the printed circuits of said board or is attached to said board (for example by soldering).

[0061] In the present case, the housing 6 comprises a first substrate 7 carrying at least one first electronic element and at least one second substrate 8 carrying at least one second electronic element.

[0062] The first substrate carries a radiofrequency antenna 9. The first substrate is also here a printed circuit board. Subsequently the first substrate is called a radiofrequency board. The radiofrequency board 7 is here carried by the upper cover 4. Preferably, the radiofrequency board 7 is carried by the upper cover 4 so as to be attached to said upper cover 4.

[0063] Optionally, a recess 10 is provided in the face of the upper cover 4 facing the inside of the housing 6 in order to house the radiofrequency antenna 9 of the radiofrequency card 7 when the radiofrequency card 7 is secured to the upper cover 4.

[0064] This limits the risk of damaging said radiofrequency antenna 9 or hindering its operation.

[0065] Therefore, the performance of the radiofrequency antenna 9 and its reliability are preserved.

[0066] More preferably, the housing 1 comprises at least one sealing element 12 compressed between the radiofrequency card 7 and the upper cover 4. For example, the upper cover 4 has a groove 11 in which the sealing element 12 is arranged at least in part.

[0067] The sealing element 12 is here arranged so as to externally surround the radiofrequency antenna 9 when the radiofrequency card 7 is fixed to the upper cover 4. It is therefore understood that the groove 11 is arranged so as to externally surround the recess 10 in the upper cover 4.

[0068] The sealing element 12 also completely encircles the radiofrequency antenna 9. It is therefore understood that the groove 11 forms a closed path in the upper cover 4.

[0069] In this way, the radiofrequency antenna 9 is well protected by being enclosed between the upper cover 4 and the radiofrequency card 7 in the recess 10 and by being surrounded by the sealing element 12.

[0070] The sealing element 12 is for example a seal. The seal is for example a silicone-based seal. The seal is for example made from sealant, such as a polymer sealant, such as a silicone-based sealant. Optionally, at least the top cover 4 and the radiofrequency card 7 are kept pressed against each other (for example by at least one clamp, at least one robotic hand, etc.) while the seal hardens.

[0071] This greatly limits the risk that a filler injected at a later stage may not reach the radiofrequency antenna 9.

[0072] The second substrate 8 carries, for example, one or more components for powering the housing 1 and / or exchanging data with the outside. The second substrate 8 is also a printed circuit board. Preferably, the second substrate 8 is connected to the radiofrequency board 7 by at least one board-to-board connector 13 (board-to-card connector 13 also arranged in the housing 6).

[0073] The second substrate 8 is here carried by the lower cover 5. Preferably the second substrate 8 is carried by the lower cover 5 by means of one or more spacers 14. In this way, the second substrate 8 is offset from the lower cover 5. The second substrate 8 thus does not directly touch the lower cover 5 and is only connected to it by means of the spacers 14.

[0074] This will simplify the removal of the lower cover 5 (which is for the moment the temporary lower cover) as will be seen later. Furthermore, the second substrate 8 carries a connector 15 which extends so as to open outside the box 2 via an orifice 16 provided on one of the lateral sides of the box 2 (i.e. in this case one of the walls of the casing 3). Preferably, the connector 15 cooperates with the orifice 16 so as to ensure a seal of the orifice 16 around the connector 15 (by pins of the connector, by a tight mounting in the orifice, by the presence of at least one seal surrounding the connector 15 and / or the orifice 16, etc.).

[0075] For example, the housing 1 can be electrically powered and / or communicated with the housing 1 via this connector 15. Furthermore, at least one of the walls of the box 2 is equipped with at least one first orifice 17 serving as an orifice for injecting the filling product and / or for controlling the insertion of the filling product into the box 2. The first orifice 17 is optionally arranged in one of the walls of the casing 3, therefore at the level of one of the lateral flanks of the box 2. For example, the first orifice 17 is provided on a flank different from that receiving the orifice of the connector 15 and for example on a flank opposite thereto. The first orifice 17 is for example centered on said flank. The first orifice 17 has for example a circular cross-section.

[0076] In addition, at least one of the walls of the box 2 is equipped with at least one second orifice 18 serving as an orifice for injecting the filling product and / or for controlling the insertion of the filling product into the box 2. The second orifice 18 may have an identical diameter, smaller or larger than the first orifice 17. The housing 1 here comprises only three orifices 17, 18, 22 serving as an orifice for injecting the filling product and / or for controlling the insertion of the filling product into the box 2.

[0077] The second orifice 18 and the third orifice 22 are provided in at least one of the walls of the box 2. The second orifice 18 and the third orifice 22 are provided on the same wall of the box 2. The second orifice 18 and the third orifice 22 are preferably provided on the same wall as the first orifice 17 or on an adjacent wall. The second orifice 18 and the third orifice 22 are arranged in one of the walls of the casing 3, therefore at the level of one of the lateral flanks of the box 2. For example, the second orifice 18 and the third orifice 22 are provided on a flank different from that receiving the orifice 16 of the connector 15 and for example on a flank opposite thereto. The second orifice 18 and the third orifice 22 have, for example, a circular cross-section. The second orifice 18 and the third orifice 22 are for example equidistant from the first orifice 17.The second orifice 18 and the third orifice 22 are for example arranged closer to the upper cover 4 than the first orifice 17. The second orifice 18 and the third orifice 22 are for example distributed symmetrically along at least one axis of symmetry belonging to the associated wall.

[0078] Optionally and non-limitingly, the different substrates are carried by walls of the box 2 other than the one(s) comprising the orifices 17, 18 and 22. In particular, the radiofrequency card 7 is secured to a wall other than that carrying the orifices 17, 18 and 22. Once the housing 1 has been assembled during the first step, the filling product can be injected inside the housing 1 during a second step illustrated in FIG. 2 and in a localized manner thanks to the presence of the orifices as described below.

[0079] For this, an operator uses an injection system 20, the terminal part of which inserts the filling product into the housing 1 via at least one of the orifices 17, 18 and 22. The injection system 20 is for example a syringe or any other device making it possible to perform this function.

[0080] A fluid filling product is chosen as the filling product, namely a liquid or semi-liquid product.

[0081] In this way, the filling product can be inserted into the gaps present inside the housing 1 even if they are small.

[0082] This limits or even eliminates the presence of air bubbles or cavities in the housing 1 not filled at the end of the second stage.

[0083] The filler here is a resin.

[0084] The resin is thus chosen so as to have a viscosity suitable for filling small spaces. In particular, the resin is sufficiently fluid to be able to fit into all the interstices present inside the housing 1. This ensures the absence of air bubbles or unfilled cavities inside the housing 1 at the end of the second stage.

[0085] The resin is also chosen to have a coefficient of expansion that is not too high to avoid damaging the housing 1 during its hardening. The resin is for example a polymer resin. The resin is for example an elastomer-based and / or silicone-based resin and / or an epoxy resin. Preferably the resin is an epoxy resin.

[0086] Furthermore, the resin here is an RTV resin (for “Room-Temperature-Vulcanizing silicone” or vulcanization at room temperature).

[0087] The resin may be a single-component or multi-component resin (either a mixture of several sub-resins and / or a mixture of at least one resin with at least a plurality of divided solids (solid and / or hollow beads, granules, powders, crystals, etc.).

[0088] Adding divided solids to the resin allows:

[0089] - to reduce the density of the injected resin and therefore the weight of the resin injected into the housing 1, and / or

[0090] - to reduce the hardness of the resin (once it has hardened as we will see later) in the case where the added divided solids are hollow and / or flexible - this allows the resin to better adapt to the thermal conditions to which it is subjected, particularly in terms of thermal expansion.

[0091] For example, the resin is two-component.

[0092] Optionally, the resin is a mixture of a first RTV sub-resin and a second RTV sub-resin. Optionally, the resin is a mixture of RTV147A and RTV147B sub-resins.

[0093] Optionally, the resin may be a two-component or multi-component resin comprising at least one silicone-based resin or at least one epoxy resin. Optionally, the resin may be a two-component or multi-component resin comprising at least one epoxy resin and at least a plurality of divided solids. Optionally, the resin may be a two-component or multi-component resin comprising at least one silicone resin and at least a plurality of divided solids.

[0094] During this second step, the operator injects the resin into the housing 1 in at least one of the orifices while monitoring the other orifices. For example, the operator injects the resin into orifice 17 while monitoring orifices 18 and 22.

[0095] When the resin begins to rise in the orifices (here 18 and 22), the operator can stop injecting the resin.

[0096] The operator can decide to stop injecting the resin when, for each orifice considered: a) it comes out completely from said orifice, or b) when the resin is flush with the external wall into which said orifice opens, or c) when the resin is present in only part of said orifice (but visible from the outside as symbolized by the eye in figure 3).

[0097] We therefore understand that the operator must ensure that one of the conditions a, b or c is met for all the orifices (here 18 and 22) to stop the injection of resin - without the condition met necessarily being the same for all the orifices.

[0098] Indeed, the fact that the resin comes out of the housing 1 and appears visually at the orifices means that it has filled the housing 1. It is noted that thanks to the sealing element 12 and the recess 10, the resin cannot reach the radiofrequency antenna 9. In this way, while protecting the housing 1, the resin does not interfere with the operation of the radiofrequency antenna 9.

[0099] The orifices advantageously make it possible to check at any time the filling of the housing 1 with the resin.

[0100] It is noted that the sealing of the orifice 16 around the connector 15 limits the risk that resin may escape through this orifice 16 during this second step.

[0101] It is noted that the volume of resin injected is greater than when simply depositing a bead to create a seal. The volume of resin injected into the housing 1 is, for example, at least 20 cubic centimeters and, for example, at least 40 cubic centimeters and, for example, at least 50 cubic centimeters.

[0102] The third step of the process consists of hardening the resin.

[0103] This curing step can be done naturally at room temperature or can be accelerated by a heating step of the housing, by a cooling step, by polymerization, by drying, by chemical reaction ... or by any known curing method. Of course the step can be broken down into several phases to harden the resin. For example, a first phase consists of bringing the filling product into contact with water or a solvent then a second step consists of natural curing at room temperature. If the curing step is done at room temperature (natural curing) then it optionally lasts between 30 and 40 hours.

[0104] If the curing step is carried out at a temperature higher than room temperature (forced curing), the housing 1 is for example heated (for example by baking). The housing 1 is for example heated to a temperature optionally between 80 and 150 degrees Celsius.

[0105] At the end of this step, the resin is in a solid state.

[0106] During a fourth step, shown diagrammatically in Figure 4, once the resin has hardened, the operator removes the temporary wall(s) (in the case described, only the lower cover 5 is concerned).

[0107] The operator preferably arranges one or more definitive walls in place: in this case, the operator arranges the definitive lower cover 5'.

[0108] The final lower cover 5' and the temporary lower cover 5 do not have the same shape as seen in Figures 8 and 9. In fact, they have different shapes so that the final lower cover 5' can define with the hardened resin at least one air gap.

[0109] For example, the temporary lower cover 5 has a flat internal surface (forming an internal wall of the housing 6 of the box 2) while the final lower cover 5' has an internal surface with at least one recess 19. As the hardened resin has been fixed against the flat surface of the temporary lower cover 5, it has a flat surface opposite the flat internal surface of the temporary lower cover 5. When the temporary lower cover 5 is replaced by the final lower cover 5', the flat surface of the resin and the recess therefore together define at least one air gap 21.

[0110] Preferably, the final lower cover 5' is shaped as a plate. The final lower cover 5' preferably has the same thickness as the temporary lower cover 5 (apart from the recess 19).

[0111] More preferably, the final lower cover 5' and the temporary lower cover 5 are identical apart from the presence of the recess 19 in the final lower cover 5'.

[0112] In fact, the recess 19 is of small dimensions so that the air blade 21 is also small.

[0113] For example, the recess 19 has a height (defined according to the direction of the thickness of the final lower cover 5') between 1 tenth of a millimeter and 1 millimeter and for example between 1 and 9 tenths of millimeters and for example between 1 and 5 tenths of millimeters and for example between 1 and 3 tenths of millimeters.

[0114] The fact that the final lower cover 5' is not attached to the resin allows it to expand if necessary inside the housing 1.

[0115] This limits the risk of breakage of an electronic element and / or a substrate in the event of expansion of the resin due to thermal variations to which the housing 1 is subjected during its operational use.

[0116] Once the final lower cover 5' is fixed to the housing 1 (for example by screwing, by gluing, etc.), the housing 1 is protected. The housing 1 thus protected is the one visible in figure 4.

[0117] Thanks to the resin, the housing 1 is well protected so as to comply with the constraints of electrical insulation, lightning resistance and resistance to explosive atmospheres (in particular in a confined environment). The housing 1 also advantageously remains compact in volume.

[0118] In addition, the radio frequency antenna 9 is not in direct contact with the resin so as not to be hindered by the resin in order to operate.

[0119] Case 1 thus proves to be reliable.

[0120] This housing 1 can be used in numerous applications and for example, with reference to figure 7, in a system for measuring a pressure 101 of a tire 102. The housing 1 is then connected on the one hand to one or more pressure sensors 103 of the tire (sensors forming part or not of the measuring system 101) and on the other hand to a computer remote from the tire 102.

[0121] Optionally, for an aircraft 100 comprising landing gear fitted with tires 102, at least one of said tires 102 can be associated with such a measuring system 101.

[0122] Of course, the invention is not limited to the implementation described but encompasses any variant falling within the scope of the invention as defined by the claims.

[0123] In particular, the shape of the housing (the box and / or the top cover and / or the bottom cover, etc.) may be different from what has been indicated. The box may therefore have a different number of parts than what has been indicated and, for example, only include two parts assembled together.

[0124] The number of control and / or injection orifices may be different from what has been indicated. The housing may even have only one orifice (for example for cases where the same volume or weight of filling product is always injected, in the case of vacuum injection, etc.). The process may include a different number of steps than what has been indicated. For example, although here the resin has been injected directly, the process may include a preliminary step of degassing the resin (which can be carried out upstream or simultaneously with the first step of assembling the housing illustrated in Figure 1). This will further limit the risk of air bubbles in the housing at the end of the protection process. Although here a temporary lower cover is used at the start of the protection process, a definitive lower cover can be used from the start of the protection process.

[0125] Alternatively or in addition to the temporary lower cover, the housing may have at least one other temporary wall at the start of the protection process, a wall optionally replaced by a definitive wall, a definitive wall optionally forming at least one air gap with the rest of the housing.

[0126] Preferably, the housing must have at least one air gap at the end of the protection process so that the filling product can expand freely inside it (along at least one expansion axis). This will make it possible to avoid or limit mechanical stresses exerted on internal components of the housing. This air gap may be defined as indicated above by the removal of a temporary cover and its replacement by a definitive cover having another shape or to do otherwise. For example, at least one of the walls of the housing (optionally the lower cover) may have on its internal face at least one layer of compressible material (such as for example sponge, foam, ...): the air gap is then created inside said layer since it can deform so that the filling product can expand freely inside the housing.It is therefore understood that the wall provided with the layer of compressible material can therefore be directly a definitive wall such as those assembled in the first step. The housing may comprise at least one other sealing element than that indicated and for example at least one sealing element arranged between the casing and at least one of the covers, around the orifice of the connector once the latter is in place in the housing, ... The sealing element may be a sealing gasket and for example a sealing gasket manufactured from a bead of mastic. The mastic forming the bead may be a polymer mastic and / or a silicone-based mastic.

[0127] Although here the injection is done in a single step, the injection could be done in several steps. For example, a first injection could be carried out followed by a pause time before at least a second injection is carried out. The pause time At could optionally be between 5 and 60 minutes and for example be between 10 and 50 minutes and for example be between 20 and 40 minutes. The operator could for example carry out a first injection until the filling product is seen in at least one of the orifices, take a pause (for example during the pause time At defined above) and then reinject the filling product a second time.

[0128] The filling product may be a foam in place of a resin. The foam may, for example, be a viscoelastic foam and / or a memory foam. The foam may, for example, be the foam marketed under the name Ecofoam. The hardening stage will then be broken down into at least two phases: a first phase of chemical reaction (the foam will swell when in contact with ambient humidity) and a second phase of hardening (the moistened foam will harden when in contact with ambient air).

[0129] The filler may be in the form of divided solids (powder, crystals, beads (solid and / or hollow), granules, etc.) instead of being a resin and / or a foam. For example, the filler may be in the form of cork granules, silica aerogel-based crystals (such as the crystals marketed under the name Kwark - registered trademark).

[0130] Although only one type of filler is injected here, it is possible to consider injecting several types of fillers simultaneously or successively into the housing to protect it. For example, a foam could be injected first, then a resin and / or a first foam, then a second foam and / or a first resin, then a second resin.

[0131] The housing may be different from what has been indicated and may be, for example, an electronic housing without a radiofrequency antenna. With or without a radiofrequency antenna, the housing may be an ATEX (ATmosphères EXplosibles) type housing, i.e. a housing complying with ATEX directives.

[0132] Although here it is an operator who carries out the injection step of the filling product, this step can be done automatically using an automatic filling system.

[0133] Although here it is an operator who decides to stop the filling product injection step, this step can be done automatically. For example, the injection can be done via an automatic filling system that will deliver a predefined volume of filling product into the housing. For example, the injection can be stopped by detecting the presence of the filling product in the orifice(s) by an optical sensor, a presence sensor, etc.

[0134] This will allow for automatic filling (with or without automatic stop) via at least one dispenser fitted on a robot.

[0135] Although here the electrical connection between two cards is ensured by at least one card-to-card connector, the electrical connection between two cards may additionally and / or as a replacement be ensured by at least one electrical wire and / or at least one electrical ribbon cable.

Claims

CLAIMS 1. Method for protecting an electronic box comprising the steps of: Injection of at least one liquid or semi-liquid filling product inside the housing (1) via at least one first orifice (17) provided in one of the walls of the housing, Stopping the injection of the product when the first orifice is at least partially filled with the product and, if the housing has one or more additional orifices provided in one or more walls of the housing, when the additional orifice(s) are also partially filled with the product, Curing of the product, the process being defined so that at the end of the protection process, the housing has at least one air gap inside the housing between at least one of the walls of the housing and the cured product.

2. Method according to claim 1, comprising an additional step of removing one of the walls of the housing (1) once the product has hardened to replace it with a wall making it possible to define an air gap (21) inside the housing between said wall and the hardened product.

3. Method according to one of the preceding claims, in which the filling product is a resin and / or a foam.

4. Method according to claim 3, in which the resin is an elastomeric and / or silicone and / or epoxy resin.

5. A method according to claim 3 or claim 4, wherein the resin is an RTV resin.

6. Method according to one of claims 3 to 5, in which the filling product is composed of at least two different by-products.

7. Method according to one of claims 3 to 6, comprising a step of prior degassing of the resin before its injection into the housing (1).

8. Method according to one of the preceding claims, in which the hardening of the product is carried out by heating the housing (1).

9. Electronic housing comprising walls jointly defining a housing (6), at least one of the walls being pierced with at least one additional orifice, the housing being furthermore filled at least in part with a filling product.

10. Housing according to claim 9, comprising a substrate (7) on which at least one antenna (9) is mounted, the substrate being mounted on a wall (4) of the housing so that the antenna faces towards said wall.

11. Housing according to claim 10, comprising at least one sealing element (12) compressed between the substrate (7) and the wall (4) carrying the substrate, the sealing element externally surrounding the antenna (9).

12. Pressure measuring system (101) of a tire (102) comprising a housing (1) according to one of claims 9 to 11.

13. Aircraft (100) provided with a measuring system (101) according to claim 12.

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