Fastener forming a reinforcement for a tank, and corresponding manufacturing and shaping methods

Abstract

A tank (1) comprising a fastener (7) extending through a body of the tank (1) via a well (6), the fastener (7) forming ends bearing on respective parts of the body in such a way as to reduce the deformation of the body in a direction (D4) in which the fastener (7) extends. A method for shaping such a fastener (7) and for manufacturing such a tank (1).

Description

[0001] Description

[0002] Title: Fastener forming a reinforcement for a tank and corresponding manufacturing and shaping methods

[0003] Technical field

[0004] 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 even hydrogen.

[0005] State of the prior art

[0006] The hydrogen, gas or liquefied gas tanks known in the prior art are generally formed from 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 permissible ruptures ranging from 8 to 157.5 MPa at rupture.

[0007] Generally speaking, known reservoirs are bulky, expensive, particularly given the time required to complete the filament winding, and liable to undergo significant deformations under the effect of variations in pressure of the fluid carried.

[0008] Furthermore, known tanks are poorly suited to current and future motor vehicles which, on the one hand, for reasons of mass to be transported, have an increasingly restricted space to accommodate such tanks and, on the other hand, pose problems of energy autonomy.

[0009] Statement of the invention

[0010] The invention aims to remedy the aforementioned problems and in particular to meet the need for additional autonomy of vehicles.

[0011] A particular aim of the invention is to provide a tank capable of storing a fluid of the biogas or hydrogen type, or more generally of containing a fluid at high pressure. Another aim of the invention is to provide a solution making it possible to maximize the useful storage volume with regard to the spaces actually available for this purpose in vehicles of the motor vehicle, aircraft, boat or other mobile equipment type.

[0012] To this end, the invention relates to a fastener 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 distant from each other along a connection direction.

[0013] According to the invention, the first end of the fastener forms a first stop surface extending around the connection direction and intended to come to bear on the first part of the body so as to prevent or limit a movement of the first part of the body in a first direction along the connection direction.

[0014] Alternatively or preferably additionally, the second end of the fastener forms a second stop surface extending around the connection direction and intended to bear on the second part of the body so as to prevent or limit movement of the second part of the body in a second direction along the connection direction, the second direction being opposite to the first direction.

[0015] Such an attachment, also called a "tie rod", 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.

[0016] 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.

[0017] Of course, a fastener 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. In one embodiment, the first abutment surface and / or the second abutment surface are frustoconical.

[0018] In one embodiment, the first abutment surface and / or the second abutment surface have one or more radii of curvature.

[0019] Preferably, the fastener comprises one or more layers made of fibers, the majority of which extend along the bonding direction.

[0020] The attachment can thus form a fibrous texture comprising a majority of fibers arranged longitudinally and grouped by a light braiding.

[0021] 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.

[0022] 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.

[0023] According to the invention, the attachment connects said first part and said second part of the tank body to each other.

[0024] These parts of the tank body, arranged opposite each other, can be flat, convex or concave walls, depending on the geometry of the body.

[0025] In one embodiment, the reservoir comprises at least one wall forming a well which passes through the cavity of the reservoir, the fastener being housed in the well.

[0026] In one embodiment, the reservoir comprises at least one load distribution ring extending radially between the attachment and the wall forming the well.

[0027] In one embodiment, the reservoir comprises one or more anti-striction nuts respectively housed in the first end and in the second end of the fastener.

[0028] In one embodiment, the tank body includes a sealing jacket and a braided shell over the jacket. The jacket may include a material such as plastic capable of sealing the jacket against the fluid contained in the cavity. More generally, the jacket may include a material of organic, plant, mineral, or metallic origin.

[0029] The liner preferably defines an internal surface which delimits the cavity and an external surface which conforms to an internal surface of the shell.

[0030] In one embodiment, the well comprises a wall formed in one piece with the jacket. In other words, this wall can form a continuous extension of material with the jacket.

[0031] The fastener and the well in which it is housed form a reinforcement extending along a connection direction, which may be perpendicular or oblique to one and / or the other of the parts of the body which are connected to each other by this reinforcement.

[0032] It is preferred that this reinforcement, in particular the wall forming the well, forms a circumferentially closed external surface around the connection direction along which it extends and that the entirety of this external surface delimits the cavity of the reservoir.

[0033] The wall of the well can simultaneously form a hollow space defining an opening crossing the reservoir in the connection direction.

[0034] In other words, said well may comprise a wall forming a solid of revolution, or more generally a solid closed around the direction of connection that it constitutes.

[0035] Without limitation, the reinforcement and the well may have a generally annular or truncated cone-shaped geometry, which may be different on different sections of the reinforcement along the connection direction.

[0036] 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 cells formed by the hollow spaces of the reinforcements, in which can in particular be housed respective fasteners in accordance with the invention. In one embodiment, the shell comprises a braiding with interlacing of plies, that is to say braided fibers, some of which, called "binding bias fibers", bind together different plies of the shell.

[0037] The following document describes the known principles of interlock plies, also known as “3D-interlock”: H. Lansiaux, D. Soulat, F. Boussu and AR Labanieh, Mechanical characterization of 3D warp interlock linen fabrics with different numbers of layers, 24th French Congress of Mechanics, Brest, August 26-30, 2019.

[0038] Such a braiding technique makes it possible to place, 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.

[0039] 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.

[0040] The shell may in particular comprise one or more layers comprising folds thus interlaced.

[0041] A shell made of braided fibers with interlacing plies makes it possible to obtain excellent mechanical properties in terms of toughness and to improve the fatigue resistance of the tank compared to a shell made by filament winding.

[0042] The tank shell thus preferably forms a texture comprising mainly continuous technical fibers. These fibers can be of organic, vegetable, mineral or metallic origin.

[0043] The orientations of the respective fibers of the shell and the attachment make it possible to respond to loading conditions that are completely different between the body and the reinforcement(s). The reinforcement(s) are in fact particularly exposed to tensile forces when the pressure is internal to the tank. The texture of the body is exposed to all kinds of constraints, namely tensile, bending, compression or even shear forces.

[0044] In one embodiment, the first abutment surface and / or the second abutment surface of the fastener bears on the shell so as to grip the shell between, on the one hand, the liner and, on the other hand, the first and / or the second abutment surface, respectively.

[0045] Among other advantages, the invention makes it possible to manufacture tanks having a resistance to high internal functional pressures, compatible with the carriage of different types of fluid, for example medium pressure natural gas (from 26 MPa in use and 47 MPa at break) or high or very high pressure hydrogen (from 35 to 70 MPa in use and from 78.75 to 157.5 MPa at break), impervious to the fluid carried, in particular when this is a gas having very small molecules such as hydrogen, methane or butane molecules, and having resistance to different types of environment (e.g. acid, basic, humidity, salt fog, etc.), static mechanical to pressure, vibration, shock, endurance, fatigue, aging, fire, ballistic and more generally mechanical, which makes it possible to increase their safety and reliability in use.

[0046] The invention also relates to a method for shaping a fastener as defined above.

[0047] This method comprises a step of deforming the first end and / or the second end of the fastener so that the first abutment surface and / or the second abutment surface can bear on the first part and / or the second part of the body, respectively.

[0048] The invention also relates to a method of manufacturing a reservoir as defined above, comprising a step of inserting, into the well, in the connection direction, a fastener as defined above.

[0049] According to a first variant, the method comprises, 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 method described above. According to a second variant, 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:

[0050] - an insertion into the well of a first part of the attachment forming said first end, in said second direction,

[0051] - an insertion into the well of a second part of the attachment forming said second end, in said first direction,

[0052] - an assembly of the first part and the second part of the attachment so as to secure these parts to each other at least in translation in the direction of connection.

[0053] This assembly of the first part and the second part of the attachment can be carried out by gluing and / or screwing or by any suitable means of securing.

[0054] In one embodiment, the method comprises, before inserting the fastener into the well, a step of braiding the interlacing fibers of plies so as to form the shell.

[0055] This braiding is preferably carried out on said jacket of the tank body, used as a mandrel.

[0056] In one embodiment, the method comprises a step of manufacturing the fastener by braiding the fibers forming this tie rod.

[0057] Other advantages and characteristics of the invention will appear on reading the detailed, non-limiting description which follows.

[0058] Brief description of the drawings

[0059] The following detailed description refers to the attached drawings in which:

[0060] [Fig. 1] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising a body and a reinforcement connecting two parts of the body facing each other;

[0061] [Fig. 2] is a partial schematic sectional view of a tank according to the invention and of a tool for assembling a fastener of a reinforcement of the tank with the body of this tank; [Fig. 3] is a partial schematic sectional view of a layer of the shell of a tank according to the invention, illustrating an example of assembly of fibers forming this layer;

[0062] [Fig. 4] is a partial schematic sectional view of a tank according to the invention and of a tool for assembling a fastener of a reinforcement of the tank with the body of this tank, this tank being distinguished in particular from that of figure 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;

[0063] [Fig. 5] is a partial schematic sectional view of a tank according to the invention and of a tool for assembling a fastener of a reinforcement of the tank with the body of this tank, this tank being distinguished in particular from that of figure 2 in that the reinforcement comprises diffusers and anti-striction nuts;

[0064] [Fig. 6] is a partial schematic sectional view of a tank according to the invention, showing a reinforcement comprising a diffuser and a clip having a curved end;

[0065] [Fig. 7] is a partial schematic 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;

[0066] [Fig. 8] is a partial schematic 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-striction nut;

[0067] [Fig. 9] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising several reinforcements oriented in a single direction, forming a mono-axial reinforcement network;

[0068] [Fig. 10] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising reinforcements oriented in two mutually orthogonal directions, forming a biaxial reinforcement network; [Fig. 11] is a schematic perspective view, partially cut away, of a tank according to the invention, comprising reinforcements oriented in three mutually orthogonal directions, forming a triaxial reinforcement network;

[0069] [Fig. 12] is a schematic sectional view of a fastener according to the invention, comprising two parts fitted into one another and glued to one another;

[0070] [Fig. 13] is a schematic sectional view of a fastener according to the invention, comprising two shouldered parts fitted into one another and glued to one another;

[0071] [Fig. 14] is a schematic sectional view of a fastener according to the invention, comprising two parts fitted into one another and glued to one another, these parts forming grooves for receiving a bonding resin;

[0072] [Fig. 15] is a schematic sectional view of a fastener according to the invention, comprising two shouldered parts fitted into one another and assembled with a ring, the assembly forming a chamber for receiving a bonding resin;

[0073] [Fig. 16] is a schematic sectional view of a fastener according to the invention, comprising two parts screwed to each other;

[0074] [Fig. 17] is a schematic sectional view of a fastener according to the invention, comprising two parts assembled together with a hoop ring; [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;

[0075] [Fig. 19] is a schematic cross-sectional view of the fastener of Fig. 18;

[0076] [Fig. 20] is a schematic view in longitudinal section of a fastener according to the invention, comprising two assembled conical parts fitted into one another;

[0077] [Fig. 21] is a schematic cross-sectional view of the fastener of Fig. 20. Detailed Description of Embodiments

[0078] Figures 1 and 9 to 11 include a reference system defining three directions DI, D2 and D3 orthogonal to each other. In this example, DI is a longitudinal direction, D2 a first transverse direction and D3 a second transverse direction.

[0079] Figure 1 shows a tank 1 according to a first embodiment of the invention.

[0080] In this non-limiting example, the tank 1 is intended to equip a motor vehicle in order to supply it with fuel.

[0081] The tank 1 of Figure 1 has a generally ovoid shape extending along a longitudinal axis A1, parallel to D1, so as to have two longitudinal ends IA and IB.

[0082] In this example, the tank 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.

[0083] As an 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.

[0084] The tank 1 comprises a body which in this example is provided with a jacket 2, a shell 3 and a reinforcement 4.

[0085] 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.

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

[0087] The shell 3 also comprises 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] Shell 3 forms an envelope of tank 1.

[0089] The inner surface of the shell 3 matches the outer surface of the jacket 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 which are located opposite each other, these opposite parts forming two transverse ends of the body according to D2. The reinforcement 4 makes it possible to improve the mechanical resistance of the tank 1, taking into account in particular the pressures and depressions which it undergoes during its use.

[0092] The reinforcement 4 has a generally elongated shape along a direction D4, called the “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 figure 1, the reinforcement 4 comprises an external envelope 6, a fastener 7 also called a “tie rod” and two diffusers 8 (only one diffuser being visible in this figure).

[0094] The reinforcement 4 and its external 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 portion 4A of the envelope 6 of the reinforcement 4 has a generally cylindrical geometry defining an axis of symmetry which corresponds to the direction D4. The end portions 4B and 4C have a flared geometry, in this case an increasing dimension from the respective end of the central portion 4A to which they are connected towards the corresponding portion of the jacket 2 to which they are connected.

[0096] The external envelope 6 of the reinforcement 4 defines, radially inside relative to the direction D4, a hollow space which passes through the jacket 2 of the body of the tank 1 in the direction D4 so as to open onto the external surface of this jacket 2.

[0097] 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.

[0098] The internal surface of the envelope 6 delimits said hollow space.

[0099] The outer surface of the envelope 6 is a circumferentially closed surface around the direction D4. In this example, the entirety of this outer surface delimits the cavity 5 of the tank 1 so that the cavity 5 extends all around the reinforcement 4.

[0100] The external envelope 6 of the reinforcement 4 thus forms a well which crosses the cavity 5.

[0101] In this example, the external envelope 6 of the reinforcement 4 is made in one piece 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.

[0102] In a non-limiting manner, the casing 6 and the jacket 2 comprise a thermoplastic material, making it possible to provide a sealing function for the fluid contained in the cavity 5.

[0103] The external envelope 6 of the reinforcement 4 is in this example made from a part previously manufactured by machining, injection, rotational molding or even extrusion-blow molding.

[0104] In the present description, the subassembly comprising in continuity of material the jacket 2 and the external envelope 6 of the reinforcement 4 is called “membrane”.

[0105] In a non-limiting manner, 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 in relation to each other using appropriate tooling, or more generally by implementing any shaping process of the rotational molding, blow molding, or other molding or casting technique, so as to create an assembly by adhesion of material elements.

[0106] There will now be described, with particular reference to figures 2 and 3, a method of assembling such a membrane (jacket 2 and external envelope 6 of the reinforcement 4) with the other elements of a reinforcement 4 and a shell 3 of a tank 1 according to the invention.

[0107] The shell 3 is first braided onto the membrane using a ply interlacing braiding process, with the membrane being used as a mandrel during braiding.

[0108] In this example, four layers are successively braided onto the mandrel.

[0109] Each of the layers comprises an assembly of fibers which in this example are carbon fibers and which are braided to form five plies.

[0110] 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 so as to successively intersect other fibers.

[0111] Figure 3 schematically shows a sectional view of a portion of a layer C1 of the shell 3, in which the assembled plies P1-P5 define a thickness of the layer C1 in 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 in 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 layer C1 in the direction D7, making it possible in particular to reduce the deformations of the shell 3 in this direction.

[0112] The C1 layer of Figure 3 comprises ten bias fibers braided onto the axial fibers 21, including two outer bias fibers 22 and eight binding bias fibers 23-30. One of the outer bias fibers 22 is braided around the axial fibers 21 of ply P1. The other outer bias fiber 22 is braided around the axial fibers 21 of ply P5. The outer bias fibers 22 smooth the outer surfaces of the C1 layer.

[0113] The binding bias fibers 23-30 are braided to connect the plies PI to P5 to each other.

[0114] More specifically, the binding bias fibers 23 and 24 connect the plies P1 and P2 to each other, the binding bias fibers 25 and 26 connect the plies P2 and P3 to each other, the binding bias fibers 27 and 28 connect the plies P3 and P4 to each other, and the binding bias fibers 29 and 30 connect the plies P4 and P5 to each other.

[0115] Thus, the binding bias fibers 23-30 are braided so as to each connect two respective adjacent plies, for example plies P1 and P2, so that two non-adjacent plies of layer C1, for example plies P1 and P3, are not connected to each other directly, but indirectly via in this example ply P2.

[0116] In this example, the binding bias fibers 24, 26, 28 and 30 are braided so as to evolve along parallel curves in the directions D5 and D6 and in phase opposition with respect to the binding bias fibers 23, 25, 27 and 29 (see figure 3).

[0117] The different layers of the shell 3 can be braided in a similar manner, preferably by modifying the relative orientation of the axial fibers 21 from one layer to another, so as to provide the shell 3 with improved mechanical resistance in several directions of space.

[0118] The shell 3 thus forms a fibrous texture which can be essentially made up of continuous interwoven fibers.

[0119] 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 binding bias fibers can be modified depending on the desired mechanical properties. Similarly, other technical fibers can be used to braid the shell 3, for example glass, basalt, aramid, linen, hemp fibers or even mixed fibers comprising 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.

[0120] Such a braiding process makes it possible to deposit layers of dry material in the form of several plies of fibers interwoven with each other, one by one or two by two or more depending on the needs. This operation can be reproduced several times, by stacking layers, in the same direction or in different directions in order to ensure a good canvas of textures capable of responding to the pressure forces generated by the fluid on the shell 3 of the tank 1.

[0121] Such a braiding process allows the deposited fibers to be shaped into the required shapes without fiber distortion and provides considerably improved properties in terms of tenacity, particularly in comparison with filament winding.

[0122] After braiding the shell 3 on the mandrel formed by said membrane, that is to say by the jacket 2 and by the external envelope 6 of the reinforcement 4, the hollow space constituted by this external envelope 6 is covered by the shell 3.

[0123] To open this hollow space towards the outside of the body formed by the jacket 2 and the shell 3, openings can be made in the shell 3 by separating the fibers which constitute it using a tool such as a conical point, so as not to cut the fibers and allow the shell 3 to retain its mechanical properties.

[0124] Figure 2 illustrates a non-limiting example in which the reinforcement 4 comprises only the external envelope 6 and the attachment 7.

[0125] The fastener 7 in this example comprises carbon fibers mainly arranged longitudinally / unidirectionally, i.e. a majority of fibers extending along the direction D4.

[0126] In this example, these fibers are connected and held together by a light braid, using a few fibers which can also be made of carbon.

[0127] Such an arrangement of fibers makes it possible, 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 into the cavity 5. Of course, other technical fibers or different combinations of fibers can be used to form the attachment 7, including for example glass fibers. Alternatively, the attachment 7 can comprise another material in combination or not with such an assembly of fibers.

[0128] In this example, the fastener 7 is manufactured in the form of a substantially tubular part having a first end 9A and a second end 9B spaced apart from each other along the connection direction D4.

[0129] After making the openings in the shell 3, by separating the fibers (see above), the prefabricated fastener 7 is introduced into the well, that is to say into the hollow space formed by the external envelope 6 of the reinforcement 4, via one of these openings, by moving the fastener 7 in translation along the direction D4.

[0130] In this example, after insertion of the attachment 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 moving two bells (not shown) moved along a shaft (not shown) which passes through the attachment 7 in the direction D4.

[0131] With reference to Figure 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 separation of fibers.

[0132] 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 jacket 2 and a part of the external envelope 6 of the reinforcement 4, ensuring a robust mechanical connection between the reinforcement 4 and the body of the tank 1.

[0133] Figure 2 shows a tool comprising a mold 31, metallic or composite, and an axis 32 passing through the attachment 7 in the direction D4. The mold 31 is held in abutment on the external surface of the shell 3 by tightening nuts 33 cooperating with the axis 32, so as to hold in position the assembly of the body of the tank 1 and the reinforcement 4 prepositioned using the aforementioned bells (not shown). Alternatively, all or part of the step of deforming the ends 9A and 9B of the attachment 7 can be carried out directly by the mold 31 rather than by bells.

[0134] The assembly of the reinforcement 4 and the body of the tank 1 is then consolidated by injection of a thermosetting resin via orifices (not shown) made in the tooling, after formation of a vacuum in the space delimited by the mold 31 and the membrane integrating the jacket 2 which provides a counter-mold function.

[0135] In this example, the injection is carried out using a process known as “Vacuum-Assisted Resin Transfer Molding” (VARTM).

[0136] The assembly is then subjected to heat treatment in order to stiffen the resin.

[0137] The thermosetting resin can be replaced by a thermoplastic resin, in particular a low viscosity one allowing injection into the fibrous texture of the shell 3, or by a bio-sourced resin.

[0138] Alternative consolidation methods can be implemented, for example the method known under the Anglo-Saxon name “Resin Transfer Molding” (RTM) or an infusion method, 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.

[0139] At the end of such an assembly, the ends 9A and 9B of the fastener 7 thus form surfaces 201A and 201B which extend in this example circumferentially around D4.

[0140] Surfaces 201A and 201B in this example have a frustoconical geometry, forming a curve which has a single radius of curvature, so as to extend radially outwards relative to D4.

[0141] The surfaces 201A and 201B thus constitute stops capable of limiting deformations of the body of the tank 1 in the direction D4.

[0142] In particular, the stop surface 201A makes it possible to prevent or at least limit a movement in a first direction along D4 of the part of the body resting on this surface 201A, that is to say the part of the body located towards the top of Figure 2, this first direction going in this case from the bottom to the top of Figure 2. The stop surface 201B makes it possible to prevent or limit a movement in a second direction along D4 of the part of the body resting on this surface 201B, that is to say the part of the body located towards the bottom of Figure 2, this second direction going from the top to the bottom of Figure 2.

[0143] Figure 4 shows a tool similar to that of Figure 2 which is specifically adapted to the assembly of a reinforcement 4 with a tank body 1 having parts connected by the reinforcement 4 which are inclined relative to the connection direction D4. The preceding description applies by analogy to this embodiment.

[0144] The tooling of Figure 4 differs in particular from that of Figure 2 in that it comprises 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 their conformation to be finalized. For comparison, in the example of Figure 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.

[0145] The preceding description also applies by analogy to the embodiment of Figure 5 which is essentially distinguished from that of Figure 2 in that the reinforcement 4 also comprises diffusers 8 and nuts 51.

[0146] The diffusers 8 are here rigid rings comprising for example a reinforced thermoplastic material each sandwiched between a respective one of the end parts of the external envelope 6 of the reinforcement 4 and the shell 3 after folding down the ends 9A and 9B of the attachment 7.

[0147] 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.

[0148] The nuts 51 are also rigid rings which may comprise a reinforced thermoplastic material and which in this example have an ogive shape. The nuts 51 are respectively housed in the ends 9A and 9B of the fastener 7, which are folded down so as to provide axial retention of the nuts 51 in the direction D4 (see figure 5 and figure 8 described further below).

[0149] In this example, the tooling and the attachment 7 are in fact 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 abutment surfaces 201A and 201B, comes to bear on the shell 3.

[0150] The nuts 51 are configured to work in compression, so as to perform an anti-striction function capable of reducing the phenomena of sliding of the ends of the reinforcement 4 relative to the shell 3.

[0151] 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.

[0152] In a non-limiting manner, the diffusers 8 and the nuts 51 may comprise materials of the polyurethane, polyamide or even polyethylene type, and be reinforced with glass, carbon or other fibers.

[0153] Figures 6 to 8 show other examples of reinforcements 4 illustrating different geometries of the end 9A of the attachment 7, after folding against a corresponding part of the body of a tank 1 according to the invention. The preceding description naturally applies by analogy to these embodiments.

[0154] In each of the embodiments of Figures 6 to 8, the reinforcement 4 comprises a diffuser s extending radially between the attachment 7 and the membrane of the body of the tank 1. According to D4, the diffuser s extends both at the central part 4A and a portion of the end part 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.

[0155] In the example of Figure 7, the end 9A of the attachment 7 has a fold forming an annular arm 202 extending radially towards the inside of the attachment 7, opposite the part of the end 9A forming the stop surface 201A. Such an arm 202 makes it possible to reinforce the resistance of the end 9A of the attachment 7 to sliding when the body of the reservoir 1 is stressed by the fluid contained in the cavity 5.

[0156] The end 9A of the fastener 7 of figure 8 is folded in a similar manner, around an anti-striction nut 51, so as to constitute a reinforcing end 4 similar to that of figure 5.

[0157] Of course, the end 9B of the reinforcement 4, not visible in figures 6 to 8, can have a geometry similar to that which has just been described, so as to form a symmetrical reinforcement 4.

[0158] Before deformation of the ends 9A and 9B of the attachment 7, epoxy resin can be sprayed onto the shell 3, in particular at the level of the parts 10, in order to prevent their relaxation and consequently their displacement.

[0159] Many variations may be implemented based on the foregoing description, both in terms of the geometry of the attachment 7 and the other parts of the tank 1, or of the members constituting the reinforcement 4 which may or may not include one or more elements including diffusers 8 and / or anti-striction nuts 51 and / or other members. For example, in an embodiment not shown, annular wall elements (not shown) made of fabric or fibers may be arranged between the attachment 7 and / or diffusers 8 and / or nuts 51 and / or the membrane of the body of the tank 1 so as to improve the distribution of loads.

[0160] Referring again to the embodiment of Figure 1, the reinforcement 4 of the reservoir 1 is in this case similar to that illustrated in Figure 5, the anti-striction nuts 51 not being shown in Figure 1.

[0161] The tank 1 of figure 1 further comprises a filling nozzle 61 integrated into the texture of the shell 3 at the longitudinal end IA of this tank 1.

[0162] The end piece 61 is configured to establish fluid communication between the cavity 5 and the outside of the tank 1, for the purpose of filling it or drawing off the fluid it contains. 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 internal jacket 2 impervious to the transported fluid and a braided shell 3, both monolithic, capable of withstanding very high pressures while considerably improving the aspects of fatigue, aging and explosion safety. In particular, depending on the geometry of the tank 1, one or more reinforcements similar to any one of the reinforcements 4 described above make it possible to significantly reduce the deformations of the body and to design a tank 1 of varied shape, conformable to the location reserved for its installation in a vehicle.A tank 1 according to the invention can in particular withstand pressures of several tens of MPa.

[0163] In particular, Figure 1 shows a tank 1 of ovoid shape comprising a single reinforcement 4.

[0164] Figures 9 to 11 show other examples of heteromorphic tanks 1 in accordance with the invention, which can be manufactured according to the same principles as those which have just been described.

[0165] Tank 1 of Figure 9 is described below only in terms of its differences from tank 1 of Figure 1, it being understood that the preceding description applies by analogy.

[0166] In the example of Figure 9, the body of the tank 1 has a generally flattened shape, in this case a dimension along the direction D2, or height, relatively small compared to its dimensions along DI and D3.

[0167] As an indication, the height according to D2 of tank 1 can be approximately 100 mm.

[0168] The jacket 2 and the shell 3 of the body define different parts 101-103 which define the shape of the tank 1. The parts 101 and 102 have a generally planar shape defining a lower wall 101 and an upper wall 102 of the body which extend parallel, facing each other. The parts 103 form side walls connecting the walls 101 and 102 so as to form rounded edges of the tank 1. The tank 1 comprises in this example a series of reinforcements 4 as described above and which are each configured to connect the parts 101 and 102 of the body to each other.

[0169] The reinforcements 4 are distributed in the tank 1, being spaced two by two at a substantially constant distance along the direction DI and along the direction D3.

[0170] 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.

[0171] Figure 10 shows another example of a tank 1 according to the invention which is described below only according to its differences from the tank 1 of Figure 9, the preceding description applying by analogy.

[0172] The tank 1 of figure 10 has a dimension in direction D2 relatively greater than the height of the tank of figure 6.

[0173] The upper part of the body comprises several upper walls 104-108 facing the lower wall 101 as well as two transverse walls 109.

[0174] 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 tank 1 at its central longitudinal part.

[0175] 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, may be approximately 150 mm.

[0176] Concerning said transverse walls 109, only one of which is visible in Figure 10, these are parallel to the directions DI and D2 and are distant from each other in the direction D3 so as to define a constant width of the tank 1.

[0177] The reinforcements 4 comprise, on the one hand, reinforcements 121 similar to those of the tank of Figure 6, that is to say reinforcements 121 connecting the lower wall 101 and the upper part of the body to each other. The reinforcements 4 also comprise reinforcements 122 which connect the transverse walls 109 of the body to each other and which in this case have a connection direction perpendicular to these walls 109 and to the connection direction of the reinforcements 121. The reinforcements 4 of the tank 1 of Figure 10 thus extend by intersecting in two different directions in space, in this case D2 and D3, forming a biaxial network of reinforcements 4.

[0178] Figure 11 shows another example of a tank 1 according to the invention which is described below only according to its differences from the tank 1 of Figure 10, the preceding description applying by analogy.

[0179] The upper part of the body comprises two upper walls 131 and 132 facing the lower wall 101, two lower longitudinal walls 133 and two upper longitudinal walls 134.

[0180] The upper walls 131 and 132 are parallel to the lower wall 101.

[0181] 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.

[0182] 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, may be approximately 400 mm.

[0183] The lower longitudinal walls 133, only one of which is visible in FIG. 11, are substantially parallel to the directions D2 and D3 and are spaced apart from each other in the direction DI so as to define a length of the tank 1.

[0184] 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 in FIG. 11) provides the connection between the upper wall 131 and the upper wall 132.

[0185] The upper longitudinal walls 134 are opposite each other and extend along a plane slightly oblique to the plane D2-D3.

[0186] The reinforcements 4 comprise reinforcements 121 similar to the reinforcements 121 of the tank of Figure 10, that is to say reinforcements 121 connecting the lower wall 101 and the upper part of the body to each other, as well as reinforcements 122 similar to the reinforcements 122 of the tank of Figure 10, connecting the transverse walls 109 of the body to each other. The reinforcements 4 also comprise reinforcements 123, some of which connect the two lower longitudinal walls 133 to each other and others connect the two upper longitudinal walls 134 to each other.

[0187] The reinforcements 4 of the tank 1 of figure 11 thus extend by intersecting in three different directions of space, in this case DI, D2 and D3, forming a tri-axial network of reinforcements 4.

[0188] It results from these various non-limiting examples that the invention makes it possible to create polymorphic tanks which can comprise a network of multi-axial / multidirectional reinforcements.

[0189] Many variations can be made to these embodiments. For example, concerning the shell 3, it can comprise a peripheral layer comprising interlacings of metal filaments such as copper, in order to protect the tank 1 against electrostatic charges.

[0190] In one embodiment, the tank 1 may comprise 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.

[0191] In one embodiment, certain wells formed during the production of the membrane can be used not to provide additional reinforcements but to fix the tank 1 to a vehicle, for example using fixing studs passing through these wells.

[0192] Furthermore, the jacket 2 and / or the external envelope 6 of the reinforcement(s) 4 may be devoid of fibers, which makes it possible to reduce the cost, or on the contrary include fibers, for example to improve the adhesion of these elements.

[0193] The geometries described above and shown in the figures are in no way limiting. In addition to the polymorphic and heteromorphic geometry of the body of the tank 1, the possible reinforcement(s) 4 and / or their external envelope 6 may have a circular, oval, square, hexagonal or other section. Of course, a tank according to the invention may be used in a transport device other than a motor vehicle, for example in an aircraft or in a railway or naval vehicle.

[0194] Furthermore, the fasteners 7 described above may be formed in two parts assembled with each other, for example in the manner illustrated in one of Figures 12 to 21, each of these parts forming a respective one of the ends 9A and 9B.

[0195] In the examples of Figures 12 to 15, the parts of the fastener 7 are fitted into each other and bonded to each other using an epoxy resin. In this regard, grooves 211 (Figure 14) or a chamber 212 (Figure 15) may be made to receive such a resin and / or a ring 213 (Figure 15) may be used, for example, to simplify the geometry of the parts forming the ends 9A and 9B and / or to simplify assembly.

[0196] The parts of the fastener 7 can also be assembled to each other by screwing (figure 16) or using a shrink-fit internal ring 221 (figure 17), the latter being able to be inserted after cooling so as to achieve tightening by thermal expansion.

[0197] In the example of Figures 18 and 19, the parts of the fastener 7 are mounted on an internal ring 231 having locking notches 232 which extend along the direction D4 and which are circumferentially spaced from each other. The parts of the fastener 7 to be assembled comprise complementary notches allowing these parts to be inserted onto the ring 231 by translating them along D4 after having placed them in a first angular position relative to the ring 231. Said parts of the fastener 7 are then blocked 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 fixed to the ends of the fastener 7 in order to improve the resistance of the ends 9A and 9B to the stresses of the body of the tank 1.

[0198] Figures 20 and 21 show yet another example of a fastener 7 comprising two conical parts, one of these parts, internal, comprising notches 241 allowing its deformation with a view to its insertion into the other part, external. After fitting these internal and external parts, a ring 242 is force-mounted so as to exert a radial holding force on the internal and external parts of the fastener 7.

[0199] A two-part attachment 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 attachment 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 assembly of the attachment 7 on the body of the tank 1.

[0200] By way of example, the part of the attachment 7 forming the 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 attachment 7 forming the end 9B can be inserted into the well in said first direction through another opening in the shell 3, these parts being able to be secured to each other using one of the techniques described above with reference to figures 12 to 21.

Claims

Tl Claims 1. Fastener (7) comprising a first end (9A) intended to be connected to a first part of a body of a tank (1) and a second end (9B) intended to be connected to a second part of said body which extends opposite said first part of the body, the first end (9A) and the second end (9B) being spaced apart from each other along a connection direction (D4), characterized in that: the first end (9A) of the fastener (7) forms a first stop surface (201A) extending around the connection direction (D4) and intended to bear on the first part of the body so as to prevent or limit a movement of the first part of the body 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 connection direction and intended to come to bear on the second part of the body so as to prevent or limit a movement of the second part of the body in a second direction along the connection direction (D4), the second direction being opposite to the first direction., 2. Fastener (7) according to claim 1, in which the first abutment surface (201A) and / or the second abutment surface (201B) are frustoconical and / or have one or more radii of curvature.

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

4. Tank (1) for a transport device such as a motor vehicle, an aircraft or a boat, comprising a body which delimits a cavity (5) intended to contain a fluid and at least one attachment (7) according to any one of claims 1 to 3, the attachment (7) connecting to each other said first part and said second part of the body of the tank.

5. Tank (1) according to claim 4, comprising at least one wall (6) forming a well which passes through the cavity (5) of the tank (1), the fastener (7) being housed in the well.

6. Tank (1) according to claim 5, comprising at least one load distribution ring (8) extending radially between the attachment (7) and the wall (6) forming the well and / or comprising one or more anti-striction nuts (51) respectively housed in the first end (9A) and in the second end (9B) of the attachment (7).

7. Tank (1) according to any one of claims 4 to 6, wherein the body of the tank (1) comprises a sealing jacket (2) and a shell (3) braided on the jacket (2), the first abutment surface (201A) and / or the second abutment surface (201B) bearing on the shell (3) so as to enclose the shell (3) between on the one hand the jacket (2) and on the other hand the first and / or the second abutment surface, respectively.

8. Method for shaping a fastener (7) according to any one of claims 1 to 3, comprising a step of deforming the first end (9A) and / or the second end (9B) of the fastener (7) so that the first abutment surface (201A) and / or the second abutment surface (201B) can come to bear on the first part and / or the second part of the body, respectively.

9. Method for manufacturing a tank (1) according to any one of claims 4 to 7 including the characteristics of claim 5, comprising a step of inserting, into the well, in the connection direction (D4), a fastener (7) according to any one of claims 1 to 3 and, after insertion of the fastener (7) into the well, a step of deformation of the first end (9A) and / or the second end (9B) of the fastener (7) according to the method of claim 8.

10. Method for manufacturing a tank (1) according to any one of claims 4 to 7 including the characteristics of claim 5, comprising a step of deforming the first end (9A) and / or the second end (9B) of the attachment (7) according to the method of claim 8 and, after deformation: an insertion into the well of a first part of the attachment (7) forming said first end (9A), in said second direction, an insertion into the well of a second part of the attachment forming said second end, in said first direction, an assembly of the first part and the second part of the attachment so as to secure these parts to each other at least in translation in the direction of connection.

Images