Attachment forming a reinforcement for tanks and corresponding manufacturing and shaping processes

Abstract

A tank (1) comprising a fastener (7) passing through a body of the tank (1) via a well (6), the fastener (7) forming ends bearing on respective parts of the body so as to reduce deformations of the body along a direction (D4) along which the fastener (7) extends. A method for shaping such a fastener (7) and for manufacturing such a tank (1). Figure for the abstract: Fig. 1

Description

Title of the invention: Attachment forming a reinforcement for a tank and corresponding manufacturing and shaping processes. Technical field

[0001] The invention relates to the field of mechanical connections and is of particular interest for tanks intended to contain fluids under high pressure such as gas, liquefied gas or hydrogen. Prior art

[0002] Hydrogen, gas or liquefied gas tanks known in the prior art are generally formed of a body comprising a cylindrical jacket on which pre-impregnated technical fibers, for example carbon, are deposited by filament winding, so as to form a shell capable of resisting the pressure of such a fluid which typically ranges from 2 to 70 MPa in use, with allowable ruptures ranging from 8 to 157.5 MPa at rupture.

[0003] In general, known reservoirs are bulky, expensive, particularly considering the time required to carry out the filament winding, and susceptible to significant deformations under the effect of pressure variations of the fluid carried.

[0004] Moreover, known tanks are poorly suited to current and future motor vehicles which, on the one hand, due to the mass to be transported, have an increasingly limited space to accommodate such tanks and, on the other hand, pose problems of energy autonomy. Description of the invention

[0005] The invention aims to remedy the aforementioned problems and in particular to meet the need for additional vehicle autonomy.

[0006] A particular object of the invention is to provide a reservoir capable of storing a fluid such as biogas or hydrogen, or more generally of containing a fluid at high pressure.

[0007] Another object of the invention is to provide a solution enabling the maximization of usable storage volume in relation to the spaces actually available for this purpose in devices such as motor vehicles, aircraft, boats or other mobile equipment.

[0008] For this purpose, the invention relates to an attachment comprising a first end intended to be connected to a first part of a body of a tank and a second end intended to be connected to a second part of said body which extends opposite said first part of the body, the first end and the second end being separated from each other along a direction of connection.

[0009] According to the invention, the first end of the attachment forms a first stop surface extending around the direction of connection and intended to bear against the first part of the body so as to prevent or limit a displacement of the first part of the body in a first direction along the direction of connection.

[0010] Alternatively or preferably complementaryly, the second end of the attachment forms a second stop surface extending around the direction of connection and intended to bear against the second part of the body so as to prevent or limit a displacement of the second part of the body in a second direction along the direction of connection, the second direction being opposite to the first direction.

[0011] Such an attachment, also called a "tie," makes it possible to increase the resistance of a tank to the pressure of the fluid carried in the tank, in particular by increasing the resistance to tensile forces.

[0012] The invention thus makes it possible to design high-pressure tanks, capable of containing fluids such as gas, liquefied gas or hydrogen, and having a heteromorphic geometry.

[0013] Of course, an attachment according to the invention can also be used to reinforce a low-pressure tank and / or one having a cylindrical or other geometry, or more generally to connect different parts of another type of structure, or even to connect different structures together.

[0014] In one embodiment, the first abutment surface and / or the second abutment surface are frustoconical.

[0015] In one embodiment, the first abutment surface and / or the second abutment surface have one or more radii of curvature.

[0016] Preferably, the fastener comprises one or more layers made of fibers, the majority of which extend along the bonding direction.

[0017] The attachment can thus form a fibrous texture comprising a majority of fibers arranged longitudinally and grouped together by a slight braiding.

[0018] Such a fibrous texture makes it possible to respond specifically to tensile forces applied to the attachment, in particular by the body of the tank under the action of the pressure exerted by the fluid it contains.

[0019] The invention also relates to a tank for a transport device such as a motor vehicle, an aircraft or a boat, comprising a body which delimits a cavity intended to contain a fluid and at least one attachment as defined above.

[0020] According to the invention, the fastener connects said first part and said second part of the tank body to each other.

[0021] These parts of the tank body, arranged opposite each other, can be flat, convex or concave walls, depending on the geometry of the body.

[0022] In one embodiment, the tank includes at least one wall forming a well which passes through the cavity of the tank, the attachment being housed in the well.

[0023] In one embodiment, the reservoir includes at least one load distribution ring extending radially between the attachment and the wall forming the well.

[0024] In one embodiment, the reservoir includes one or more anti-restriction nuts respectively housed in the first end and in the second end of the attachment.

[0025] In one embodiment, the tank body comprises a sealing jacket and a braided shell on the jacket.

[0026] The liner may comprise a material such as plastic suitable for making the liner leak-proof against the fluid contained in the cavity. More generally, the liner may comprise a material of organic, vegetable, mineral, or metallic origin.

[0027] The sleeve preferably defines an internal surface which delimits the cavity and an external surface which fits an internal surface of the shell.

[0028] In one embodiment, the well comprises a wall formed from the material along with the liner. In other words, this wall can form a continuous extension of the material with the liner.

[0029] The attachment and the well in which it is housed form a reinforcement extending along a direction of connection, which may be perpendicular or oblique with respect to one and / or the other of the body parts which are connected to each other by this reinforcement.

[0030] It is preferred that this reinforcement, in particular the wall forming the well, forms an external surface circumferentially closed around the direction of connection along which it extends and that the entirety of this external surface delimits the cavity of the reservoir.

[0031] The well wall can simultaneously form a hollow space defining an opening through the reservoir along the connection direction.

[0032] In other words, said well may include a wall forming a solid of revolution, or more generally a solid closed around the direction of connection that it constitutes.

[0033] By way of non-limitation, the reinforcement and the well may have an overall annular or frustoconical geometry, which may be different on different sections of the reinforcement along the direction of connection.

[0034] A tank comprising several reinforcements defining such hollow spaces can thus form a honeycomb structure, the jacket delimiting a volume comprising the fluid storage cavity crossed by alveoli formed by the hollow spaces of the reinforcements, in which can in particular be housed respective fasteners according to the invention.

[0035] In one embodiment, the shell comprises an interlaced plies braid, that is to say, braided fibers, some of which, called "binding bias fibers", bind between them are different folds of the shell.

[0036] The following document describes principles known in themselves of interlacing pleat braiding, also known as "3D-Interlock": H. Lansiaux, D. Soulat, F. Boussu and AR Labanieh, Mechanical characterization of 3D interlock warp linen fabrics with different numbers of layers, 24th French Congress of Mechanics, Brest, August 26-30, 2019.

[0037] Such a braiding technique makes it possible to deposit, at the same time, on a mandrel made to the internal shape of the tank for example, a certain number of braids while interlacing them together in order to avoid, in use, any delamination or any movement between the different braids and thus make them work together.

[0038] This technique also allows the construction of a polymorphic shell, whether it is a shell with a simple or classic geometry of the cylindrical type or a complex heteromorphic geometry.

[0039] The shell may in particular comprise one or more layers comprising such interlaced folds.

[0040] A shell made of braided fibers with interlaced folds makes it possible in particular to obtain excellent mechanical properties in terms of toughness and to improve the fatigue resistance of the tank compared with a shell made by filament winding.

[0041] The tank shell thus preferably forms a structure comprising mainly continuous technical fibers. These fibers may be of organic, vegetable, mineral or metallic origin.

[0042] The respective fiber orientations of the shell and the attachment allow the body and the reinforcement(s) to respond to loading conditions that are completely different. The reinforcement(s) are particularly exposed to tensile forces when the pressure is inside the tank. The body's structure, on the other hand, is exposed to all kinds of stresses, namely tensile, bending, compressive, and shear forces.

[0043] In one embodiment, the first stop surface and / or the second stop surface of the attachment rests on the shell so as to clamp the shell between on the one hand the sleeve and on the other hand the first and / or the second stop surface, respectively.

[0044] Among other advantages, the invention makes it possible to manufacture tanks with resistance to high internal operating pressures, compatible with the transport of different types of fluid, for example, natural gas at medium pressure (26 MPa in use and 47 MPa at rupture) or hydrogen at high or very high pressure (35 to 70 MPa in use and 78.75 to 157.5 MPa at rupture), leak-proof to the fluid carried, particularly when the latter is a gas containing molecules of very small sizes such as hydrogen, methane or butane molecules, and exhibiting resistance to different types of environment (e.g. acid, basic, humidity, salt spray, etc.), static mechanical pressure, vibration, shock, endurance, fatigue, aging, fire, ballistic and more generally mechanical, which allows for increased safety and reliability in use.

[0045] The invention also relates to a method for shaping a fastener as defined above.

[0046] This method includes a step of deforming the first end and / or the second end of the fastener so that the first stop surface and / or the second stop surface can bear against the first part and / or the second part of the body, respectively.

[0047] The invention also relates to a method for manufacturing a tank as defined above, comprising a step of inserting, in the well, along the direction of connection, an attachment as defined above.

[0048] According to a first variant, the method includes, after insertion of the fastener into the well, a step of deforming the first end and / or the second end of the fastener according to the shaping process described above.

[0049] According to a second embodiment, the method comprises a step of deforming the first end and / or the second end of the fastener according to the shaping method described above and, after deformation: - an insertion into the well of a first part of the fastener forming said first end, along said second direction, - an insertion into the well of a second part of the fastener forming said second end, according to said first direction, - an assembly of the first part and the second part of the fastener so as to secure these parts to each other at least in translation along the direction of connection.

[0050] This assembly of the first part and the second part of the fastener can be achieved by gluing and / or screwing or by any appropriate means of fastening.

[0051] In one embodiment, the process includes, before inserting the fastener into the well, a step of braiding the fibers with interlacing folds so as to form the shell.

[0052] This braiding is preferably carried out on said tank body sleeve, used as a mandrel.

[0053] In one embodiment, the process includes a step of manufacturing the fastener by braiding the fibers forming this tie.

[0054] Other advantages and features of the invention will become apparent from the following detailed, non-limiting description. Brief description of the drawings

[0055] The detailed description that follows refers to the accompanying drawings in which:

[0056] [Fig-1] is a schematic perspective view, partially cut away, of a reservoir according to the invention, comprising a body and a reinforcement connecting two parts of the body opposite each other;

[0057] [Fig.2] is a partial schematic cross-sectional view of a tank conforming to the invention and a tooling allowing the assembly of a reinforcement attachment of the tank with the body of this tank;

[0058] [Fig.3] is a partial schematic cross-sectional view of a layer of the shell of a tank according to the invention, illustrating an example of a fiber assembly forming this layer;

[0059] [Fig.4] is a partial schematic cross-sectional view of a tank according to the invention and of a tooling for assembling an attachment of a tank reinforcement with the body of this tank, this tank being distinguished in particular from that of [Fig.2] in that the parts connected to each other by the reinforcement are walls inclined relative to each other and relative to a direction along which the reinforcement extends;

[0060] [Fig.5] is a partial schematic cross-sectional view of a tank according to the invention and of a tooling for assembling an attachment of a tank reinforcement with the body of this tank, this tank being distinguished in particular from that of [Fig.2] in that the reinforcement includes diffusers and anti-restriction nuts;

[0061] [Fig.6] is a partial schematic cross-sectional view of a tank according to the invention, showing a reinforcement comprising a diffuser and a fastener having a curved end;

[0062] [Fig.7] is a partial schematic cross-sectional view of a tank according to the invention, showing a reinforcement comprising a diffuser and a fastener having one end folded back on itself;

[0063] [Fig.8] is a partial schematic cross-sectional view of a tank according to the invention, showing a reinforcement comprising a diffuser and a fastener having one end folded over an anti-restriction nut;

[0064] [Fig.9] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising several reinforcements oriented along a single direction, forming a mono-axial reinforcement network;

[0065] [Fig. 10] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising reinforcements oriented along two directions orthogonal to each other, forming a bi-axial reinforcement network;

[0066] [Fig. 11] is a schematic perspective view, partially cut away, of a reservoir according to the invention, comprising reinforcements oriented along three directions orthogonal to each other, forming a tri-axial reinforcement network;

[0067] [Fig. 12] is a schematic cross-sectional view of a fastener according to the invention, comprising two parts fitted one inside the other and glued to each other;

[0068] [Fig. 13] is a schematic cross-sectional view of a fastener according to the invention, comprising two shouldered parts fitted one inside the other and glued to each other;

[0069] [Fig. 14] is a schematic cross-sectional view of a fastener according to the invention, comprising two parts fitted one inside the other and glued to each other, these parts forming grooves for receiving a bonding resin;

[0070] [Fig. 15] is a schematic cross-sectional view of a fastener according to the invention, comprising two shouldered parts fitted one into the other and assembled with a ring, the assembly forming a receiving chamber for a bonding resin;

[0071] [Fig.16] is a schematic cross-sectional view of a fastener according to the invention, comprising two parts screwed together;

[0072] [Fig. 17] is a schematic cross-sectional view of a fastener according to the invention, comprising two parts assembled together with a shrink ring;

[0073] [Fig. 18] is a schematic longitudinal sectional view of a fastener according to the invention, comprising two parts assembled together with a ring forming locking notches;

[0074] [Fig. 19] is a schematic cross-sectional view of the attachment of the [Fig. 18];

[0075] [Fig.20] is a schematic longitudinal cross-sectional view of a fastener conforming to the invention, comprising two conical parts assembled and fitted one inside the other;

[0076] [Fig.21] is a schematic cross-sectional view of the attachment of [Fig.20]. Detailed description of implementation methods

[0077] Figures 1 and 9 to 11 include a reference frame defining three directions D1, D2 and D3 orthogonal to each other. In this example, D1 is a longitudinal direction, D2 a first transverse direction and D3 a second transverse direction.

[0078] Figure [Fig. 1] shows a reservoir 1 conforming to a first embodiment of the invention.

[0079] In this example, which is by no means limiting, the tank 1 is intended to equip a motor vehicle in order to supply it with fuel.

[0080] The reservoir 1 of [Fig.l] has an overall ovoid shape extending along a longitudinal axis Al, parallel to Dl, so as to present two longitudinal ends IA and IB.

[0081] In this example, the reservoir 1 has a transverse dimension, in particular along D2, which varies along the axis AL. Starting from the longitudinal end IA, This transverse dimension increases up to a median longitudinal coordinate, then decreases up to the longitudinal end IB.

[0082] For the sake of indication, the maximum transverse dimension of the tank 1 according to D2, which is located in this case at the level of said median longitudinal coordinate, can be approximately 500 mm.

[0083] The tank 1 comprises a body which in this example is provided with a liner 2, a shell 3 and a reinforcement 4.

[0084] The jacket 2 forms an internal surface and an external surface defining a thickness of this jacket 2, which in this example is substantially constant in the different parts of the tank 1.

[0085] The internal surface of the sleeve 2, which also forms an internal surface of the body of the tank 1, delimits a cavity 5 intended to contain a pressurized fluid constituting in this example said fuel.

[0086] In this example, the cavity 5 is intended to contain a fluid fuel, gas or liquid, having a pressure of the order of 70 MPa.

[0087] The shell 3 also includes an internal surface and an external surface defining a thickness of this shell 3, which in this example is substantially constant in the different parts of the tank 1.

[0088] The shell 3 forms an envelope of the tank 1.

[0089] The internal surface of the shell 3 fits the external surface of the liner 2.

[0090] The jacket 2 and the shell 3 thus constitute a double-walled body and each have respective and complementary properties taking into account their respective material and manufacturing process (see further below).

[0091] In this example, the reinforcement 4 is configured to connect two parts of the body that are located opposite each other, these opposite parts forming two transverse extremities of the body along D2. The reinforcement 4 improves the mechanical resistance of the tank 1, particularly with regard to the pressures and vacuums it undergoes during its use.

[0092] The reinforcement 4 has an overall elongated shape along a direction D4, called "connection direction", which in this example is parallel to the direction D2 and which passes through said median longitudinal coordinate of the tank 1.

[0093] In the non-limiting example of [Fig. 1], the reinforcement 4 comprises an outer envelope 6, a fastener 7 also called a "tie" and two diffusers 8 (only one diffuser being visible in this figure).

[0094] The reinforcement 4 and its outer envelope 6 comprise a central part 4A and end parts 4B and 4C respectively connected to said transverse ends of the body in the manner described further below.

[0095] In this example, the central part 4A of the envelope 6 of the reinforcement 4 has a geometry globally cylindrical defining an axis of symmetry which corresponds to the direction D4.

[0096] The end parts 4B and 4C have a flared geometry, in this case a dimension increasing from the respective end of the central part 4A to which they are connected towards the corresponding part of the sleeve 2 to which they are connected.

[0097] The outer envelope 6 of the reinforcement 4 defines, radially inside with respect to the direction D4, a hollow space which crosses the sleeve 2 of the body of the tank 1 in the direction D4 so as to open onto the outer surface of this sleeve 2.

[0098] The envelope 6 thus forms a wall which extends circumferentially around D4, forming an internal surface and an external surface which define a thickness of this wall.

[0099] The internal surface of the envelope 6 delimits said hollow space.

[0100] The external surface of the envelope 6 is a circumferentially closed surface around the direction D4. In this example, the entirety of this external surface delimits the cavity 5 of the tank 1 so that the cavity 5 extends all around the reinforcement 4.

[0101] The outer envelope 6 of the reinforcement 4 thus forms a well which passes through the cavity 5.

[0102] In this example, the outer envelope 6 of the reinforcement 4 is made of material with the jacket 2, in this case with parts of the jacket 2 forming said transverse ends of the body, so as to form a continuous extension of material.

[0103] By way of non-limitation, the casing 6 and the sleeve 2 comprise a thermoplastic material, enabling a sealing function for the fluid contained in the cavity 5.

[0104] The outer envelope 6 of the reinforcement 4 is in this example made from a part previously manufactured by machining, injection, rotomolding or extrusion blow molding.

[0105] In this description, the subassembly comprising in continuous material the jacket 2 and the outer envelope 6 of the reinforcement 4 is called "membrane".

[0106] By way of non-limitation, the membrane can be obtained by crystallization or crosslinking of thermoplastic material consisting on the one hand of said prefabricated part and on the other hand of wall elements held together with respect to each other using appropriate tooling, or more generally by implementing any shaping process of the type rotomolding, blow molding, or other molding or casting technique, so as to create an assembly by adhesion of material elements.

[0107] A method for assembling such a membrane (sleeve 2 and outer casing 6 of the reinforcement 4) with the other elements of a reinforcement 4 and a shell 3 of a tank 1 conforming to will now be described, with reference in particular to Figures 2 and 3. the invention.

[0108] The shell 3 is first braided onto the membrane using a pleat interlacing braiding process, the membrane being used as a mandrel during the braiding.

[0109] In this example, four layers are successively braided onto the mandrel.

[0110] Each of the layers comprises an assembly of fibers which in this example are carbon fibers and which are braided in such a way as to form five plies.

[0111] Conventionally, depending on their arrangement in the assembly, the fibers are called "axial fibers" when they are arranged in a substantially linear manner and "bias fibers" when they are arranged in such a way as to successively intersect other fibers.

[0112] Figure 3 schematically shows a cross-sectional view of a portion of a Cl layer of the shell 3, in which the assembled plies P1-P5 define a thickness of the Cl layer along a direction D5. Each of the plies P1-P5 comprises a series of axial fibers 21, also called "longis," which are spaced from each other along a direction D6 perpendicular to the direction D5 and to a direction D7 along which they extend. The axial fibers 21 specifically increase the mechanical strength of the Cl layer in the direction D7, thereby reducing deformations of the shell 3 in this direction.

[0113] The Cl layer of [Fig.3] comprises ten bias fibers braided onto the axial fibers 21, among which are two external bias fibers 22 and eight binding bias fibers 23-30.

[0114] One of the external bias fibers 22 is braided around the axial fibers 21 of the PL ply. The other external bias fiber 22 is braided around the axial fibers 21 of the P5 ply. The external bias fibers 22 smooth the external surfaces of the CL layer.

[0115] The bias binding fibers 23-30 are braided so as to link the plies PI to P5 to each other.

[0116] More specifically, the bias binding fibers 23 and 24 link the plies PI and P2 together, the bias binding fibers 25 and 26 link the plies P2 and P3 together, the bias binding fibers 27 and 28 link the plies P3 and P4 together, and the bias binding fibers 29 and 30 link the plies P4 and P5 together.

[0117] Thus, the bias binding fibers 23-30 are braided so as to link each of two respective adjacent plies, for example plies PI and P2, so that two non-adjacent plies of layer Cl, for example plies PI and P3, are not linked to each other directly, but indirectly through in this example plies P2.

[0118] In this example, the bias binding fibers 24, 26, 28 and 30 are braided so as to evolve along parallel curves in directions D5 and D6 and in op- phase position relative to the bias bond fibers 23, 25, 27 and 29 (see [Fig.3]).

[0119] The different layers of the shell 3 can be braided in a similar manner, preferably by changing the relative orientation of the axial fibers 21 from one layer to another, so as to give the shell 3 improved mechanical strength in several directions of space.

[0120] The shell 3 thus forms a fibrous texture that can be essentially made up of interlaced continuous fibers.

[0121] Of course, the number of layers of the shell 3 and / or the number of plies per layer and / or the number of plies directly connected to each other by bias binding fibers can be modified according to the desired mechanical properties. Similarly, other technical fibers can be used to braid the shell 3, for example, glass, basalt, aramid, flax, hemp, or mixed fibers including, for example, polyamide or polyethylene filaments. The braiding of the shell 3 can also be carried out using a combination of such technical fibers and thermoplastic filaments.

[0122] Such a braiding process allows layers of dry material to be deposited in the form of several interlaced fiber plies, one by one, two by two, or even more, as required. This operation can be repeated several times, by stacking layers, in the same direction or in different directions to ensure a good framework of textures capable of withstanding the pressure forces generated by the fluid on the shell 3 of the tank 1.

[0123] Such a braiding process allows the deposited fibers to conform to the required shapes without fiber distortion and provides considerably improved properties in terms of toughness, particularly compared with a filament winding.

[0124] After braiding the shell 3 onto the mandrel formed by said membrane, i.e. by the sleeve 2 and by the outer envelope 6 of the reinforcement 4, the hollow space constituted by this outer envelope 6 is covered by the shell 3.

[0125] To open this hollow space to the outside of the body formed by the sleeve 2 and the shell 3, openings can be made in the shell 3 by separating the fibers that constitute it using a tool such as a conical point, so as not to cut the fibers and to allow the shell 3 to retain its mechanical properties.

[0126] Fig. 2 illustrates a non-limiting example in which the reinforcement 4 comprises only the outer cover 6 and the fastener 7.

[0127] The fastener 7 in this example comprises carbon fibers mainly arranged longitudinally / unidirectionally, i.e. a majority of fibers extending along the direction D4.

[0128] In this example, these fibers are linked and held together by a light braiding, using some fibers which may also be made of carbon.

[0129] Such a fiber arrangement allows, when the attachment 7 is assembled with the other parts of the tank 1, to form a reinforcement 4 capable of resisting tensile forces exerted on this reinforcement 4 under the action of the pressure of the fluid carried in the cavity 5.

[0130] Of course, other technical fibers or different combinations of fibers can be used to form the fastener 7, including, for example, glass fibers. Alternatively, the fastener 7 may comprise another material, either in combination with or not with such a fiber assembly.

[0131] In this example, the fastener 7 is made in the form of a substantially tubular part having a first end 9A and a second end 9B separated from each other along the connection direction D4.

[0132] After making the openings in the shell 3, by spreading fibers (see above), the prefabricated fastener 7 is introduced into the well, i.e. into the hollow space formed by the outer envelope 6 of the reinforcement 4, via one of these openings, by moving the fastener 7 in translation along the direction D4.

[0133] In this example, after insertion of the fastener 7 into the well, the ends 9A and 9B are simultaneously deformed so as to fold them against the body of the tank 1, for example by displacement of two bells (not shown) moved along a shaft (not shown) which passes through the fastener 7 in the direction D4.

[0134] With reference to [Fig.2], the ends 9A and 9B of the fastener 7 are thus folded against parts 10 of the shell 3 which delimit said openings obtained by spreading fibers.

[0135] In this example, the parts 10 of the shell 3 are thus sandwiched between, on the one hand, surfaces 201A and 201B of the attachment 7 called "stop surfaces" and, on the other hand, the membrane, in this case a part of the liner 2 and a part of the outer casing 6 of the reinforcement 4, ensuring a robust mechanical connection between the reinforcement 4 and the body of the tank 1.

[0136] Figure 2 shows tooling comprising a mold 31, metallic or composite, and a shaft 32 passing through the fastener 7 in the direction D4. The mold 31 is held against the outer surface of the shell 3 by tightening nuts 33 cooperating with the shaft 32, so as to hold in position the assembly of the tank body 1 and the reinforcement 4 pre-positioned using the aforementioned bells (not shown). Alternatively, all or part of the deformation step of the ends 9A and 9B of the fastener 7 can be carried out directly by the mold 31 rather than by bells.

[0137] The assembly of the reinforcement 4 and the tank body 1 is then consolidated by injecting a thermosetting resin through orifices (not shown) made in the tooling, after the formation of a vacuum in the space delimited by the mold 31 and the membrane incorporating the sleeve 2 which provides a counter-mold function.

[0138] In this example, the injection is carried out using a process known under the Anglo-Saxon name "Vacuum-Assisted Resin Transfer Molding" (VARTM).

[0139] The assembly is then subjected to heat treatment in order to stiffen the resin.

[0140] The thermosetting resin can be replaced by a thermo-type resin plastic, in particular low viscosity allowing injection into the fibrous texture of the shell 3, or even by a bio-based resin.

[0141] Alternative consolidation processes can be implemented, for example the process known under the Anglo-Saxon name "Resin Transfer Molding" (RTM) or an infusion process, or even consolidation by thermocompression for example when the shell 3 and / or the attachment 7 comprise a mixture of technical fibers and thermoplastic matrix filaments.

[0142] Following such an assembly, the ends 9A and 9B of the fastener 7 thus form surfaces 201A and 201B which in this example extend circumferentially around D4.

[0143] In this example, surfaces 201A and 201B have a frustoconical geometry, forming a curve that has a single radius of curvature, so as to extend radially outwards with respect to D4.

[0144] The surfaces 201A and 201B thus constitute stops capable of limiting deformations of the body of the tank 1 along the direction D4.

[0145] In particular, the stop surface 201A prevents or at least limits a displacement in a first direction along D4 of the part of the body bearing on this surface 201A, that is to say the part of the body located towards the top of [Fig. 2], this first direction being in this case from the bottom to the top of [Fig. 2]. The stop surface 201B prevents or limits a displacement in a second direction along D4 of the part of the body bearing on this surface 201B, that is to say the part of the body located towards the bottom of [Fig. 2], this second direction being from the top to the bottom of [Fig. 2].

[0146] Figure 4 shows tooling similar to that in Figure 2 which is specifically adapted for the assembly of a reinforcement 4 with a tank body 1 having parts connected by the reinforcement 4 which are inclined with respect to the connection direction D4. The preceding description applies by analogy to this embodiment.

[0147] The tooling of [Fig.4] differs in particular from that of [Fig.2] in that it includes heads 41 forming molds, centered on the axis 32 in openings of the mold 31. The heads 41 are arranged at the ends 9A and 9B of the attachment 7 so as to keep them folded against the shell 3 and optionally allow for final shaping. By way of comparison, in the example of [Fig. 2], the geometry of the folded ends 9A and 9B of the attachment 7 results in particular from the shape of the molds 31 themselves and / or of said bells.

[0148] The preceding description also applies by analogy to the embodiment of [Fig.5] which differs essentially from that of [Fig.2] in that the reinforcement 4 also includes diffusers 8 and nuts 51.

[0149] The diffusers 8 are here rigid rings comprising for example a reinforced thermoplastic material each sandwiched between one of the respective end parts of the outer envelope 6 of the reinforcement 4 and the shell 3 after folding down the ends 9A and 9B of the attachment 7.

[0150] Such diffusers 8 make it possible to improve the distribution of loads on the hull 3, in particular when the ends 9A and 9B of the attachment 7 are folded down.

[0151] The nuts 51 are also rigid rings which may include a reinforced thermoplastic material and which in this example have an ogive shape.

[0152] The nuts 51 are respectively housed in the ends 9A and 9B of the fastener 7, which are folded down so as to achieve axial retention of the nuts 51 in the direction D4 (see [Fig.5] and [Fig.8] described further below).

[0153] In this example, the tooling and the attachment 7 are indeed configured so that, when the ends 9A and 9B of the attachment 7 are folded down, the nuts 51 are enveloped by a radially internal surface of the ends 9A and 9B and a radially external surface of the ends 9A and 9B, forming said stop surfaces 201A and 201B, and come to rest on the shell 3.

[0154] The nuts 51 are configured to work in compression, so as to achieve an anti-stress function capable of reducing the sliding phenomena of the ends of the reinforcement 4 relative to the shell 3.

[0155] Such anti-restriction nuts 51 are particularly useful for tanks 1 intended to contain a fluid under high or very high pressure, such as hydrogen.

[0156] By way of non-limitation, the diffusers 8 and the nuts 51 may comprise materials such as polyurethane, polyamide or polyethylene, and be reinforced with glass, carbon or other fibers.

[0157] Figures 6 to 8 show further examples of reinforcements 4 illustrating different geometries of the end 9A of the fastener 7, after being folded against a corresponding part of the body of a tank 1 according to the invention. The preceding description applies, of course, by analogy to these embodiments.

[0158] In each of the embodiments shown in Figures 6 to 8, the reinforcement 4 comprises a diffuser 8 extending radially between the fastener 7 and the membrane of the reservoir body 1. According to D4, the diffuser 8 extends both at the central portion 4A and at a portion of the end portion 4C of the casing 6 forming the well. The abutment surface 201A formed by the end 9A visible in these figures has a curved geometry with a double radius of curvature.

[0159] In the example of [Fig. 7], the end 9A of the fastener 7 has a fold forming an annular arm 202 extending radially inwards towards the inside of the fastener 7, opposite the part of the end 9A forming the abutment surface 201A. Such an arm 202 makes it possible to increase the resistance of the end 9A of the fastener 7 to sliding when the body of the reservoir 1 is stressed by the fluid contained in the cavity 5.

[0160] The end 9A of the fastener 7 of [Fig.8] is folded in a similar manner, around an anti-strain nut 51, so as to constitute a reinforcing end 4 similar to that of [Fig.5].

[0161] Of course, the end 9B of the reinforcement 4, not visible in figures 6 to 8, can have a geometry similar to that just described, so as to form a symmetrical reinforcement 4.

[0162] Before deformation of the ends 9A and 9B of the fastener 7, epoxy resin can be sprayed on the shell 3, in particular at the parts 10, in order to prevent their relaxation and consequently their displacement.

[0163] Numerous variations can be implemented based on the preceding description, both in terms of the geometry of the attachment 7 and the other parts of the reservoir 1, or of the components constituting the reinforcement 4, which may or may not include one or more elements including diffusers 8 and / or anti-restriction nuts 51 and / or other components. For example, in an embodiment not shown, annular wall elements (not shown) made of fabric or fibers can be arranged between the attachment 7 and / or diffusers 8 and / or nuts 51 and / or the membrane of the reservoir body 1 so as to improve load distribution.

[0164] With further reference to the embodiment of [Fig.1], the reinforcement 4 of the reservoir 1 is in this case similar to that illustrated in [Fig.5], although the anti-restriction nuts 51 are not shown in [Fig.1].

[0165] The reservoir 1 of [Fig.1] further includes a filling nozzle 61 integrated into the structure of the shell 3 at the longitudinal end 1A of this reservoir 1.

[0166] The nozzle 61 is configured to establish fluidic communication between the cavity 5 and the outside of the reservoir 1, for the purpose of filling it or taking the fluid it contains.

[0167] It follows from the preceding description that the invention makes it possible to produce a composite tank 1, in this case having a body formed of an inner liner 2 that is leak-proof against the transported fluid and a braided shell 3, both monolithic, capable of withstanding very high pressures while considerably improving fatigue, aging, and explosion safety. In particular, depending on the geometry of the tank 1, one or more reinforcements similar to one Any of the reinforcements 4 described above make it possible to significantly reduce body deformations and to design a tank 1 of various shapes, conformable to the space reserved for its installation in a vehicle. A tank 1 according to the invention is particularly capable of withstanding pressures of several tens of MPa.

[0168] In particular, [Fig.1] shows an ovoid-shaped reservoir 1 comprising a single reinforcement 4.

[0169] Figures 9 to 11 show other examples of heteromorphic reservoirs 1 according to the invention, which can be manufactured according to the same principles as those just described.

[0170] Reservoir 1 of [Fig.9] is described below only in terms of its differences from reservoir 1 of [Fig.1], it being understood that the preceding description applies by analogy.

[0171] In the example of [Fig.9], the body of the tank 1 has an overall flattened shape, in this case a dimension along the direction D2, or height, relatively small compared to its dimensions along DI and D3.

[0172] As an indication, the height according to D2 of the tank 1 can be approximately 100 mm.

[0173] The shirt 2 and the body shell 3 define different parts 101-103 which de The final shape of the tank 1 is defined by parts 101 and 102, which have a generally flat shape, defining a lower wall 101 and an upper wall 102 of the body that extend parallel to each other. Parts 103 form lateral walls connecting walls 101 and 102 so as to form rounded edges of the tank 1.

[0174] The tank 1 in this example comprises a series of reinforcements 4 as described above and which are each configured to connect parts 101 and 102 of the body to each other.

[0175] The reinforcements 4 are distributed in the tank 1, spaced two by two at a substantially constant distance along the DI direction and along the D3 direction.

[0176] Of course, the geometry, position and number of reinforcements 4 can be modified without departing from the scope of the invention, depending on the distribution of forces in the tank 1 during its use, which depends in particular on the geometry of the body.

[0177] Figure 10 shows another example of a tank 1 according to the invention which is described below only in terms of its differences from reservoir 1 of [Fig.9], the preceding description applying by analogy.

[0178] The tank 1 of [Fig. 10] has a dimension along the direction D2 relatively larger than the height of the tank of [Fig. 6].

[0179] The upper part of the body comprises several upper walls 104-108 in vis- opposite the lower wall 101 as well as two transverse walls 109.

[0180] The upper walls 104, 106 and 108 are parallel to the lower wall 101 while the upper walls 105 and 107 are inclined relative to the walls 104, 106 and 108 so as to create a bulge in the reservoir 1 at the level of its central longitudinal part.

[0181] As an indication, the maximum height of the tank 1, i.e. the distance along D2 between the lower wall 101 and the upper wall 106, can be approximately 150 mm.

[0182] Regarding said transverse walls 109, only one of which is visible on [Fig. 10], these are parallel to the directions DI and D2 and are spaced apart from each other along the direction D3 so as to define a constant width of the reservoir 1.

[0183] The reinforcements 4 comprise, on the one hand, reinforcements 121 similar to those of the tank in [Fig. 6], that is, reinforcements 121 connecting the lower wall 101 and the upper part of the body. The reinforcements 4 also comprise, on the other hand, reinforcements 122 that connect the transverse walls 109 of the body and that, in this case, have a connection direction perpendicular to these walls 109 and to the connection direction of the reinforcements 121.

[0184] The reinforcements 4 of the tank 1 of [Fig.10] thus extend by intersecting along two different directions in space, in this case D2 and D3, forming a bi-axial network of reinforcements 4.

[0185] [Fig. 11] shows another example of a tank 1 according to the invention which is described below only in terms of its differences from the tank 1 of [Fig. 10], the preceding description applying by analogy.

[0186] The upper part of the body comprises two upper walls 131 and 132 opposite the lower wall 101, two lower longitudinal walls 133 and two upper longitudinal walls 134.

[0187] The upper walls 131 and 132 are parallel to the lower wall 101.

[0188] The distance along D2 between the lower wall 101 and the upper wall 131 is greater than the distance along D2 between the lower wall 101 and the upper wall 132, forming a stepped reservoir.

[0189] As an indication, the maximum height of the tank 1, i.e. the distance along D2 between the lower wall 101 and the upper wall 131, can be approximately 400 mm.

[0190] The lower longitudinal walls 133, only one of which is visible in [Fig. 1 1], are substantially parallel to the directions D2 and D3 and are separated from each other along the direction DI so as to define a length of the tank 1.

[0191] One of the upper longitudinal walls 134 provides the connection between one of the lower longitudinal walls 133 and the upper wall 131, while the other upper longitudinal wall (not visible on [Fig.1 1]) provides the connection between the upper wall 131 and the upper wall 132.

[0192] The upper longitudinal walls 134 are opposite each other and extend along a slightly oblique plane relative to the D2-D3 plane.

[0193] The reinforcements 4 include reinforcements 121 similar to the reinforcements 121 of the tank in [Fig. 10], that is, reinforcements 121 connecting the lower wall 101 and the upper part of the body, and reinforcements 122 similar to the reinforcements 122 of the tank in [Fig. 10], connecting the transverse walls 109 of the body. The reinforcements 4 also include reinforcements 123, some of which connect the two lower longitudinal walls 133 and others of which connect the two upper longitudinal walls 134.

[0194] The reinforcements 4 of the tank 1 of [Fig.1 1] thus extend by intersecting in three different directions of space, in this case D1, D2 and D3, forming a tri-axial network of reinforcements 4.

[0195] It follows from these various non-limiting examples that the invention makes it possible to create polymorphic reservoirs that can include a network of multi-axial / multi-directional reinforcements.

[0196] Numerous variations can be made to these embodiments. For example, with regard to the shell 3, it can include a peripheral layer comprising interlacing metallic filaments such as copper, in order to protect the reservoir 1 against electrostatic charges.

[0197] In one embodiment, the tank 1 may include a dimensional control device formed by an interlacing of optical, inductive or laser-charged filaments allowing the detection of defects or failures generated during the life of the tank 1.

[0198] In one embodiment, certain wells formed during the making of the membrane can be used not to make additional reinforcements but to fix the tank 1 to a vehicle, for example using fixing studs passing through these wells.

[0199] Furthermore, the jacket 2 and / or the outer envelope 6 of the reinforcement(s) 4 may be free of fibers, which reduces the cost, or on the contrary include fibers, for example to improve the adhesion of these elements.

[0200] The geometries described above and shown in the figures are in no way limiting. In addition to the polymorphic and heteromorphic geometry of the tank body 1, the possible reinforcement(s) 4 and / or their outer casing 6 may have a circular, oval, square, hexagonal or other cross-section.

[0201] Of course, a tank according to the invention can be used in a transport device other than a motor vehicle, for example in an aircraft or in a railway or naval vessel.

[0202] Furthermore, the fasteners 7 described above can be formed in two parts as joined together, for example in the manner illustrated in one of figures 12 to 21, each of these parts forming one of the respective ends 9A and 9B.

[0203] In the examples in Figures 12 to 15, the parts of the fastener 7 are fitted together and bonded together with an epoxy resin. In this regard, grooves 211 ([Fig. 14]) or a chamber 212 ([Fig. 15]) can be made to receive such a resin and / or a ring 213 ([Fig. 15]) can be used, for example, to simplify the geometry of the parts forming the ends 9A and 9B and / or to simplify the assembly.

[0204] The parts of the fastener 7 can also be assembled to each other by screwing ( [Fig.16]) or by means of a shrink-fitted inner ring 221 ( [Fig.17]), the latter being able to be inserted after cooling so as to achieve tightening by thermal expansion.

[0205] In the example of Figures 18 and 19, the parts of the fastener 7 are mounted on an inner ring 231 having locking notches 232 extending along the direction D4 and circumferentially spaced from each other. The parts of the fastener 7 to be assembled include additional notches allowing these parts to be inserted onto the ring 231 by translating them along D4 after they have been placed in a first angular position relative to the ring 231. These parts of the fastener 7 are then locked along D4 relative to the ring 231 by placing them in a second angular position relative to the ring 231. In this example, heads 233 are attached to the ends of the fastener 7 to improve the resistance of the ends 9A and 9B to stresses from the body of the tank 1.

[0206] Figures 20 and 21 show yet another example of a fastener 7 comprising two conical parts, one of these parts, the inner part, having notches 241 allowing it to be deformed for insertion into the other, outer part. After these inner and outer parts are fitted together, a ring 242 is press-fitted so as to exert a radial retaining force on the inner and outer parts of the fastener 7.

[0207] A two-part fastener 7, for example according to one of the embodiments of Figures 12 to 21 or according to other variants not shown, makes it possible to simplify the manufacture and assembly of the fastener 7 on the body of the tank 1. This also makes it possible to shape the ends 9A and 9B, for example by deformation, before mounting the fastener 7 on the body of the tank 1.

[0208] By way of example, the part of the fastener 7 forming end 9A can be inserted into the well through one of the openings made in the shell 3 in the manner described above, in this case in said second direction, while the part of the fastener 7 forming end 9B can be inserted into the well in said first direction by a another opening of the hull 3, these parts being able to be joined together using one of the techniques described above with reference to figures 12 to 21.

Claims

Demands

1. Tank (1) for a transport apparatus such as a motor vehicle, an aircraft or a boat, comprising a body which delimits a cavity (5) intended to contain a fluid, the body comprising a sealing jacket (2), a shell (3) and at least one reinforcement (4), the reinforcement (4) comprising an outer casing (6) and an attachment (7), the outer casing (6) of the reinforcement (4) forming a well through the cavity (5) in a direction of connection (D4) and being made of material with said jacket (2), the shell (3) comprising openings through which a hollow space formed by the outer casing (6) of the reinforcement (4) opens, the attachment (7) being housed in said hollow space and comprising a first end (9A) connected to a first part of the shell (3) and a second end (9B) connected to a second part of the shell (3) which extends opposite said first part of the shell (3),the first end (9A) and the second end (9B) being separated from each other along said connection direction (D4), characterized in that: - the first end (9A) of the fastener (7) forms a first stop surface (201 A) extending around the connection direction (D4) and bearing against a part (10) of the shell (3) which delimits one of said openings of the shell (3) so as to enclose this part (10) of the shell (3) between the sleeve (2) and said first stop surface (201A) of the fastener (7) so as to prevent or limit a displacement of the first part of the shell (3) in a first direction along the connection direction (D4), and / or - the second end (9B) of the fastener (7) forms a second stop surface (201B) extending around the direction of connection and bearing against a portion (10) of the shell (3) which delimits the other of said openings in the shell (3) so as to enclose this portion (10) of the shell (3) between the sleeve (2) and said second stop surface (201B) of the fastener (7) so as to prevent or limit a displacement of the second portion of the shell (3) in a second direction along the direction of connection (D4), the second direction being opposite to the first direction, and in that the first end (9A) and the second end (9B) are flared so that the first stop surface (201A) and the second stop surface (201B) have one or more radii of curvature.

2. Reservoir (1) according to claim 1, wherein the first stop surface (201A) and / or the second stop surface (201B) of the attachment (7) are frustoconical.

3. Reservoir (1) according to claim 1 or 2, wherein the attachment (7) comprises one or more layers made of fibers, the majority of which extend along the bonding direction (D4).

4. Reservoir (1) according to any one of claims 1 to 3, comprising at least one load distribution ring (8) extending radially between the fastener (7) and the outer casing (6) forming the well and / or comprising one or more anti-strain nuts (51) respectively housed in the first end (9A) and in the second end (9B) of the fastener (7).

5. A method for manufacturing a tank (1) according to any one of claims 1 to 4, comprising a step of shaping a fastener (7) of the tank (1), this shaping step comprising a step of deforming the first end (9A) and / or the second end (9B) of the fastener (7) so that the first buttress surface (201A) and / or the second buttress surface (201B) can bear against the first part and / or the second part of the shell (3), respectively.

6. Method according to claim 5, comprising, before the deformation step, a step of inserting the fastener (7), into the well, along the connection direction (D4).

7. A method according to claim 5, comprising, after the deformation step: - an insertion into the well of a first part of the fastener (7) forming said first end (9A), along said second direction, - an insertion into the well of a second part of the fastener forming said second end, along said first direction, - an assembly of the first part and the second part of the fastener so as to secure these parts to each other at least in translation along the direction of connection.

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