FR3136710A1 - Polymorphic tanks and corresponding manufacturing processes - Google Patents

Abstract

Tank (1) for a transport device such as a motor vehicle, an aircraft or a boat, comprising a body which delimits a cavity (4) intended to contain a fluid, in particular a gas, the body comprising walls (5- 7) forming an envelope (2) of the tank (1) and one or more reinforcements (3), each of the reinforcements (3) connecting two of said walls (5, 6) arranged opposite each other screw in relation to each other. Process for manufacturing such a tank (1). Figure for abstract: Fig. 1

Description

Polymorphic tanks and corresponding manufacturing processes

The invention relates to the field of fluid storage, in particular a fluid forming a fuel contained in a tank of a transport device such as a motor vehicle, an aircraft, a boat, or any other mobile equipment.

The invention is of particular interest, in no way limiting, in the sector of vehicles using gas as fuel.

State of the prior art

In the transport sector, the use of gas as fuel helps reduce greenhouse gas emissions.

Given the limited space available for storing fuel in contemporary and future transportation devices, one solution is to use not a single tank as large as possible but several small tanks.

The use of several tanks of restricted size makes it possible in particular to reduce the mechanical stresses exerted by the fluid stored on the tanks, and therefore to reduce the thickness of their shell.

However, there is a need to increase the useful fluid storage volume taking into account the space actually available to place the tank(s).

The invention aims to provide a solution for storing a fluid under pressure by maximizing the useful storage volume while reducing the risks resulting from the pressure exerted by the fluid thus stored.

To this end, the subject of the invention is a reservoir 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, in particular a gas, the body comprising walls forming an envelope of the tank. According to the invention, the body comprises one or more reinforcements, each of the reinforcements connecting two of said walls arranged opposite each other.

The size of the tank, that is to say the total volume that it occupies in space, is mainly determined by the geometry of its envelope and therefore by the geometry of said walls, which designate different parts of the envelope which can together constitute a single, monolithic piece. In particular and in a clever way, the reinforcements can remain completely contained in this volume.

According to the proposed arrangement, the reinforcements occupy a space in the tank which could constitute an additional part of the fluid storage cavity. However, such an arrangement of reinforcements makes it possible to improve the mechanical resistance of the envelope and to confer the required mechanical properties to the tank, the envelope of which can have a very wide variety of geometries.

The invention thus makes it possible to produce a polymorphic reservoir, optimizing the fluid storage volume formed by the cavity taking into account the space actually available in the vehicle that it is intended to equip.

This storage volume can thus be greater than that which would be constituted by a conventional cylindrical tank, or by an assembly of conventional tanks and makes it possible to eliminate the connections between tanks as well as the risks associated with such an assembly.

Depending on the shape of the space available for the tank, the latter may comprise a relatively simple geometry, for example a generally parallelepiped shape or other elementary shapes, or comprise several parts, at least some of which have a relatively simple geometry. The tank can also include parts of more complex shape, for example defining convex or concave walls or surfaces and/or walls or surfaces respectively oriented in different directions of space.

The reinforcements make it possible to join together different parts of the envelope, in this case the walls that they connect, so as to locally reinforce the mechanical resistance of the tank.

The invention thus makes it possible to improve both the compactness, the storage volume and the mechanical resistance of the tank.

In one embodiment, the reinforcements come integrally with the envelope.

In other words, the reinforcements can form a continuous extension of material with the envelope, in particular with the walls that they connect.

Generally speaking, each of the reinforcements can have a connection direction along which it extends.

The direction of connection of each of the reinforcements can be perpendicular or oblique with respect to one and/or the other of the first walls which are connected to each other by this reinforcement.

By way of non-limiting example, in the case of a reinforcement connecting two walls parallel to each other, the direction of connection of this reinforcement can be perpendicular to each of these walls. In the case of a reinforcement connecting two walls oblique to each other, the direction of connection of this reinforcement can be perpendicular to one of these walls and oblique by relation to the other of these walls.

In one embodiment, each of the reinforcements, or at least one among them, forms an external surface circumferentially closed around the direction of connection.

Preferably, the entirety of this external surface, or at least part of it, delimits the cavity.

In one embodiment, each of the reinforcements, or at least one among them, forms an internal surface delimiting a hollow space.

Preferably, this hollow space defines an opening which passes through the tank in the connection direction.

In other words, a given reinforcement can be formed by a wall which forms a solid of revolution or more generally by a solid closed around the direction of connection that it constitutes.

By way of non-limiting example, such a reinforcement may have a generally annular or frustoconical geometry, which may be different on different sections of the reinforcement along the connection direction.

A tank comprising reinforcements forming such hollow spaces can thus form a cellular structure, the envelope delimiting a volume comprising the fluid storage cavity crossed by cells formed by the hollow spaces of the reinforcements.

A reinforcement provided with such a hollow space makes it possible both to fulfill its mechanical strength function, to reduce the mass of the tank and, when the hollow space forms an opening passing through the tank, to form empty spaces in which can be housed additional elements such as tank fixing elements.

In one embodiment, the connection direction of one or more of said reinforcements is perpendicular or oblique relative to the connection direction of one or more other of said reinforcements.

In particular, in a non-limiting manner, certain reinforcements can connect two walls of the tank which extend for example parallel to a first reference direction while other reinforcements can connect two walls of the tank which extend in this direction. example parallel to a second reference direction oblique or perpendicular to the first reference direction.

In one embodiment, each of the reinforcements, or at least one among them, comprises a first end part secured to one of said walls which it connects, a second end part secured to the other of said walls that it connects and a central part extending between the first end part and the second end part.

As a non-limiting example, the central part may have a tubular geometry.

The first end part and/or the second end part can each have an increasing dimension going from the central part towards the first wall to which it is respectively connected.

Such a geometry of the end parts makes it possible to reduce the shear stresses introduced by the internal pressure of the tank.

Preferably, the walls and/or reinforcements comprise a material chosen from thermoplastics, such as polyethylene, polyamide, polyurethane, thermosets, and biosourced resins.

Among other advantages of these materials, thermoplastic in particular makes it possible to give the body of the tank flexibility and resistance properties.

The invention also relates to a transport device such as a motor vehicle, an aircraft or a boat, comprising one or more tanks as defined above.

According to another aspect, the invention relates to a method of manufacturing a tank as defined above.

This method preferably comprises a step of assembling elements of material so as to form a continuous extension of material between the envelope and the reinforcement(s).

In a non-limiting manner, the assembly can be carried out by molding, for example by rotation and/or by extrusion and blowing.

In one embodiment, the body of the tank is manufactured in one piece.

Alternatively, the tank body can be manufactured by assembling several previously manufactured parts.

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

The detailed description which follows refers to the appended drawings in which:

is a schematic perspective view, partially cut away, of a tank conforming to a first embodiment of the invention, the tank comprising reinforcements oriented in a single direction, forming a network of mono-axial reinforcements;

is a partial schematic perspective view of a reservoir similar to that of the , showing four adjacent reinforcements;

is a schematic perspective view, partially cut away, of a tank conforming to a second embodiment of the invention, the tank comprising reinforcements oriented in two mutually orthogonal directions, forming a network of bi-axial reinforcements;

is a schematic perspective view, partially cut away, of a tank conforming to a third embodiment of the invention, the tank comprising reinforcements oriented in three mutually orthogonal directions, forming a network of tri-axial reinforcements;

is a partial schematic sectional view of manufacturing elements of a tank according to a first mode of implementation of the invention;

is a partial schematic sectional view of manufacturing elements of a tank according to a second mode of implementation of the invention;

is a partial schematic sectional view of manufacturing elements of a tank according to a third mode of implementation of the invention.

Detailed description of embodiments

Figures 1 to 4 include a frame of reference defining three mutually orthogonal directions D1, D2 and D3. In this example, D1 is a longitudinal direction, D2 a vertical direction and D3 a transverse direction.

He is represented on the a tank 1 conforming to a first embodiment of the invention.

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

In reference to the , the tank 1 has a generally flattened shape, in this case a dimension in the vertical direction D2, or height, relatively small compared to its longitudinal and transverse dimensions, that is to say in the directions D1 and D3 respectively.

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

The dimension of the tank 1 according to the transverse direction D3, or width, varies along the direction D1. Starting from the longitudinal end located towards the left and the bottom of the , the width increases up to a first longitudinal coordinate, remains constant up to a second longitudinal coordinate then decreases up to the opposite longitudinal end, located towards the right and the top of the .

In this example, the tank 1 comprises a body forming an envelope 2, also called a “shell”, as well as reinforcements 3.

The envelope 2 delimits the external contours of a cavity 4 intended to contain a fluid under pressure which constitutes said fuel in this example.

In this example, cavity 4 is intended to contain a fluid, gas or liquid, having a pressure of around 300 MPa.

The envelope 2 is formed of different walls 5-7, also called “skins”, which are in this example made in one piece (see further below), so as to form a monolithic shell.

In reference to the , the envelope 2 more precisely comprises a lower wall 5, an upper wall 6 and side walls 7.

The lower wall 5 and the upper wall 6 are spaced apart from each other in the direction D2 so as to define on the one hand the height of the tank 1, which corresponds to the distance along D2 between an external surface of the wall lower 5 and an external surface of the upper wall 6 and, on the other hand, a height of the cavity 4 which corresponds to the distance along D2 between an internal surface of the lower wall 5 and an internal surface of the upper wall 6.

In this example, the walls 5 and 6 are parallel, facing each other, and the side walls 7 connect the walls 5 and 6 to each other so as to form edges rounding of tank 1.

The reservoir 1 also comprises a filling member 8 having in this example a tubular geometry and being integral with one of the side walls 7.

The member 8 is configured to establish fluid communication between the cavity 4 and the exterior of the reservoir 1, with a view to filling it or sampling the fluid it contains.

The reinforcements 3 are in this example configured to connect the walls 5 and 6 to each other, so as to reinforce the mechanical resistance of the envelope 2 and therefore of the tank 1, taking into account in particular the pressures and depressions that it suffers during its use.

In reference to the which shows part of a tank 1 similar to that of the , each of the reinforcements 3 has a generally elongated shape along a direction D4, called “connection direction”. In this example, the connection direction D4 of each of the reinforcements 3 is substantially parallel to the vertical direction D1 and therefore substantially perpendicular to the walls 5 and 6.

The geometry of a reinforcement 3 will now be described with reference to the second reinforcement 3 starting from the right of the .

The reinforcement 3 comprises a central part 11, a lower end part 12 connected to the wall 5 and an upper end part 13 connected to the wall 6.

The central part 11 has a cylindrical geometry and has an axis of symmetry which corresponds to the direction D4.

The lower end part 12 has a flared geometry, in this case an increasing dimension from the end of the central part 11 to which it is connected towards the wall 5. Similarly, the upper end part 13 has also a flared geometry having an increasing dimension from the end of the central part 11 to which it is connected towards the wall 6.

In this example, the central part 11 and the end parts 12 and 13 define radially inside with respect to the direction D4 a hollow space 14 which crosses the tank 1 in the direction D4 (visible on the ).

The wall constituted by these different parts 11, 12 and 13 of the reinforcement 3 thus extends circumferentially around the connection direction D4 by defining an internal surface and an external surface.

The internal surface of the reinforcement 3 delimits said hollow space 14. In this example, this internal surface of the reinforcement 3 is connected to, or opens onto, the external surface of the walls 5 and 6.

The external surface of the reinforcement 3 is a circumferentially closed surface around the direction D4 and the entirety of this external surface delimits the cavity 4 of the tank 1. In other words, the cavity 4 extends all around the reinforcement 3.

In this example, reinforcement 3 thus forms a well which passes through cavity 4.

The other reinforcements 3 represented on the , as well as each of the reinforcements 3 of the tank 1 of the are similar to reinforcement 3 which has just been described.

In reference to the , the reinforcements 3 are distributed over the entire length and width of the tank 1, being spaced two by two at a substantially constant distance in direction D1 and in direction D3.

Of course, the geometry, position and number of reinforcements 3 can be modified without departing from the scope of the invention, depending on the distribution of forces in the tank 2 during its use, which depends in particular on the geometry of envelope 2.

In this example, the envelope 2 and the reinforcements 3 comprise a thermoplastic material.

Each of the 3 reinforcements of the is also made of material with the envelope 2, more precisely with the walls 5 and 6, so as to form a continuous extension of material.

Optionally, the envelope 2 and/or the reinforcements 3 can also include technical fillers or fibers in order to increase resistance to pressure forces generated by the fluid. In a non-limiting manner, the thermoplastic matrix can be reinforced by mineral or fibrous fillers, by filaments of glass, carbon, aramid, basalt, or even by plant fibers, so as to produce a fibrous texture. Such fillers or fibers can be integrated into the thermoplastic matrix for example by weaving, braiding, roto-molding, blowing or even by injection.

The reinforcements 3 and/or the envelope 2 may include an additive in order to improve adhesion with the retained base and/or be doped with adjuvants, for example in the form of nanoparticles, in order to reinforce the sealing properties, the mechanical strength and/or resistance to pressure of tank 1.

Alternatively, the envelope 2 and/or the reinforcements 3 can be manufactured by deposition, for example by roto-molding, of several layers of different thermoplastic materials which, agglomerated together, ensure better sealing or mechanical properties. .

Methods for manufacturing such a tank 1 are described further below by way of example.

There shows a tank 1 according to a second embodiment which is described below only according to its differences compared to that of the . The preceding description applies by analogy to this second embodiment.

In this example, the tank 1 has a dimension in the direction D2 relatively greater than the height of the tank of the .

The upper part of the envelope 2 comprises several upper walls 61-65 facing the lower wall 5 as well as two transverse walls 71.

The upper walls 61, 63 and 65 are parallel to the lower wall 5 while the upper walls 62 and 64 are inclined relative to the walls 61, 63 and 65 so as to create a bulge in the tank 1 at its central longitudinal part. .

In particular, the distance along D2 between the lower wall 5 and the upper wall 63 is greater than the distance along D2 between the lower wall 5 and the upper walls 61 and 65. The distance along D2 between the lower wall 5 and the upper wall 62 evolves monotonically along D1 so as to achieve a transition between the upper walls 61 and 63. Likewise, the distance along D2 between the lower wall 5 and the upper wall 64 evolves monotonically along D1 so as to achieve a transition between the upper walls 63 and 65.

As an indication, the maximum height of tank 1, that is to say the distance along D2 between the lower wall 5 and the upper wall 63, can be approximately 150 mm.

Concerning said transverse walls 71, only one of which is visible on the , these are parallel to directions D1 and D2 and are distant from each other in direction D3 so as to define a constant width of tank 1.

The reinforcements 3 comprise on the one hand reinforcements 31 similar to those of the tank of the , that is to say reinforcements 31 connecting the lower wall 5 and the upper part of the envelope 2 to each other. Thus, certain reinforcements 31, called "first reinforcements", connect one to the other. the other the lower wall 5 and the upper wall 61, or the lower wall 5 and the upper wall 63, or the lower wall 5 and the upper wall 65. Other reinforcements 31, called "second reinforcements", connect the one to the other the lower wall 5 and the upper wall 62, or the lower wall 5 and the upper wall 64. Taking into account the respective orientation of the walls 5 and 61-65, the first reinforcements 31 have a connection direction perpendicular to the walls 5, 61, 63 and 65 to which they are respectively connected, while the second reinforcements 31 have a direction of connection perpendicular to the lower wall 5 and oblique with respect to the upper walls 62 and 64 to which they are respectively connected.

The reinforcements 3 also comprise reinforcements 32 which connect the transverse walls 71 to each other and which in this case have a direction of connection perpendicular to these walls 71 and to the direction of connection reinforcements 31.

Reinforcements 3 of tank 1 of the thus extend by intersecting in two different directions of space, in this case D2 and D3, forming a bi-axial network of reinforcements 3.

There shows a tank 1 according to a third embodiment which is described below only according to its differences compared to that of the . The preceding description applies by analogy to this third embodiment.

The upper part of the envelope 2 comprises two upper walls 66 and 67 facing the lower wall 5, two lower longitudinal walls 72 and two upper longitudinal walls 73.

The upper walls 66 and 67 are parallel to the lower wall 5.

The distance along D2 between the lower wall 5 and the upper wall 66 is greater than the distance along D2 between the lower wall 5 and the upper wall 67, forming a stepped tank.

As an indication, the maximum height of tank 1, that is to say the distance along D2 between the lower wall 5 and the upper wall 66, can be approximately 150 mm.

The lower longitudinal walls 72, only one of which is visible on the , are substantially parallel to directions D2 and D3 and are spaced apart from each other in direction D1 so as to define a length of tank 1.

One of the upper longitudinal walls 73 provides the connection between one of the lower longitudinal walls 72 and the upper wall 66, while the other upper longitudinal wall 73 (not visible on the ) ensures the connection between the upper wall 66 and the upper wall 67.

The upper longitudinal walls 73 face each other and extend along a plane slightly oblique to the plane D2-D3.

The reinforcements 3 comprise on the one hand reinforcements 31 similar to the reinforcements 31 of the tank of the , that is to say reinforcements 31 connecting the lower wall 5 and the upper part of the envelope 2 to each other. Thus, certain reinforcements 31 connect the lower wall 5 to each other and the upper wall 66 and other reinforcements 31 connect the lower wall 5 and the upper wall 67 to each other.

The reinforcements 3 also include reinforcements 32 similar to the reinforcements 32 of the tank of the , connecting the transverse walls 71 of the envelope 2 to each other.

In this embodiment, the reinforcements 3 also include reinforcements 33, some of which connect the two lower longitudinal walls 72 to each other and others which connect the two upper longitudinal walls 73 to each other.

Reinforcements 3 of tank 1 of the thus extend, intersecting in three different directions of space, in this case D1, D2 and D3, forming a tri-axial network of reinforcements 3.

The invention thus makes it possible to create polymorphic reservoirs that can include a network of multi-axial/multi-directional reinforcements.

Non-limiting examples of methods of manufacturing tanks conforming to the invention will now be described.

Reinforcements 3 of the well type, for example those of the tank 1 of the , can be manufactured in the manner described below with reference to the which shows tooling and material elements intended to form one of the reinforcements 3 as well as the walls 5 and 6 of the envelope 2.

Said material elements comprise, on the one hand, a part 101 comprising a central part 102 and two end parts 103 and 104 and, on the other hand, wall elements 105 and 106.

Part 101 is in this example prefabricated by machining, injection, roto-molding or even extrusion-blowing.

The tooling includes a mold provided with outer shells 111 and 112, well heads 113 and 114, a centering pin 115 and a holding rod 116.

The outer shells 111 and 112 are arranged opposite each other and closed on top of each other so as to delimit an interior volume delimited by surfaces of the shells 111 and 112 on which said elements walls 105 and 106 are arranged using a roto-molding process, blow molding or a similar process.

The end parts 103 and 104 of the part 101 have a general shape progressively widened as one approaches the respective wall elements 105 and 106 so as to allow their substantially tangential connection to these wall elements 105 and 106 The part 101 thus extends over the entire distance separating the wall elements 105 and 106.

The wall elements 105 and 106 are arranged so as to cover the ends of the part 101 to ensure effective anchoring. This solution is particularly preferred for materials of high viscosity where the material has difficulty being injected even when hot.

In this example, the centering pin 115 has a cylindrical shape and can be solid or hollow. It is arranged in an adjusted manner inside the part 101 so as to extend at the level of the central part 102. The centering pin 115 is fitted at its respective ends into the wellheads 113 and 114, which are themselves centered and held between the two shells 111 and 112 of the mold which include corresponding openings or passages for this purpose. The centering pin 115 thus constitutes a spacer between the wellheads 113 and 114.

In this example, the centering pin 115 contributes to maintaining the well heads 113 and 114 resting against opposite surfaces of the mold shells, the well heads comprising a shoulder resting against these surfaces. The centering pin 115 is intended to hold the part 101 between the shells 111 and 112 of the mold prior to the shaping and crystallization of the material of the wall elements 105 and 106. This pin 115 can be drilled radially to improve heat exchanges during the shaping process, which can be a roto-molding, extrusion-blowing or similar process.

Each of the wellheads 113 and 114 has a shape gradually widening between the centering axis 115 and the corresponding shell 111, 112 of the mold to which it is connected. These well heads extend the internal shape of the mold shells on which the material of the wall elements 105 and 106 will be deposited during the shaping process.

In this example, the wellheads 113 and 114 form cores along which the material will be deposited, and these wellheads maintain the part 101 in position, centered on the axis A1 along which it extends. Alternatively, the wellheads 113 and 114 can essentially serve to hold the part 101 in position, centered on the axis A1, by constituting support zones for the part 101 in the end parts 103 and 104.

The holding rod 116 is intended to pass along the axis A1 of the part 101 the shells 111 and 112, the well heads 113 and 114, the centering axis 115, as well as the part 101. This holding rod 116 comprises tightening means at these ends, such as nuts screwed onto threaded parts, making it possible to keep the elements assembled together with appropriate tightening. This assembly using a holding rod 116 prevents any bending of the part 101 during the softening phase, allowing marriage with the material of the wall elements 105 and 106.

This non-limiting process thus comprises the following steps:
– installation and maintenance between the two wellheads 113 and 114 of the centering pin 115 inside the part 101, this centering pin 115 being fitted onto the wellheads 113 and 114;
– positioning and maintaining the shells 111 and 112 of the mold before closing these shells one on the other, of the assembly formed by the centering pin 115, the part 101 and the well heads 113 and 114 ;
– installation of the holding rod 116 passing through the shells 111 and 112, the well heads 113 and 114, the centering pin 115 and the part 101 via corresponding passages provided in each of these elements;
– final shaping of the material inside the mold, in order to create the body of the tank.

After crystallization or crosslinking of the thermoplastic material, the mold is dismantled, the holding rod 116 is removed, the shells 111 and 112 of the mold are opened, the well heads 113 and 114 are removed, as well as the centering pin 115 There then remains the envelope 2 formed by the wall elements 105 and 106 as well as the reinforcement formed by the part 101 made integrally with the wall elements 105 and 106, the material of the end parts 103 and 104 forming an extension continuous with the material of the wall elements 105 and 106.

Of course, the method described above can be implemented to produce several reinforcements 3 simultaneously.

Many variations can be made to this manufacturing process, for example that which is described below with reference to the by distinction with that of the . The preceding description applies by analogy.

In the example of the , the outer shells 111 and 112 of the mold and the well heads 113 and 114 are configured so that the well heads 113 and 114 are clamped between the centering axis 115 and, respectively, the outer shells 111 and 112.

The material elements intended to form the envelope and the reinforcement comprise on the one hand a prefabricated tubular part 121 and, on the other hand, wall elements 105 and 106 which comprise parts 122 and 123 intended to form said parts of ends of the reinforcement.

The end parts 122 and 123 have a general shape that is progressively restricted as one approaches the respective ends of the part 121 so as to allow their substantially tangential connection to this part 121.

This manufacturing variant can for example be used to manufacture a relatively long reinforcement or several reinforcements of variable length by varying the length of the part 121.

In a manner known per se, the admissible length of the reinforcement depends on the material used and the conditions of implementation. For example, in the context of roto-molding, the adjustment parameters include the rotation speed, the fluidity of the material or even the softening point of this material. Typically, the use of a thermoplastic such as polyethylene HD 1000 is suitable for manufacturing a 50 mm reinforcement in the manner described above.

There illustrates tools and material elements used in a manner analogous to what has just been described with reference to the , for the manufacture of reinforcements connecting facing walls inclined relative to each other. The preceding description applies by analogy to the example of the .

According to the invention, the body of the tank 1, including the envelope 2 and the reinforcements 3, can therefore be manufactured using a shaping process of the roto-molding or blow-molding type, or any other technique molding or casting, so as to create an assembly by adhesion of material elements forming on the one hand the walls of the envelope and on the other hand the reinforcements. To do this, when the reinforcements form wells, the tooling can include members for holding the elements of material intended to form the reinforcements, these members being housed in the parts forming these wells during molding. When the reinforcements are not hollow but solid, they can be positioned axially in the mold by fitting onto pivots placed in the mold.

The methods described above are suitable for the manufacture of tanks 1 comprising reinforcements 3 which have connection directions substantially parallel to each other, or slightly oblique to each other, forming a mono-axial network as illustrated in the .

To manufacture a tank 1 equipped with intersecting reinforcements 3 forming a multi-axial network of reinforcements, such as those illustrated in Figures 3 and 4, the external mold can comprise different parts each presenting the pivots necessary for maintaining the well supports. Alternatively, the mold can include keys representative of each of the faces presenting the pivots holding the wells, which keys can then be enclosed in an external mold.

The invention is not limited to the embodiments and variants described above. In general, the invention makes it possible to produce polymorphic tanks, capable of conforming to available volumes, which makes it possible to increase the fluid carrying capacity and therefore the autonomy of the vehicles they equip. The invention thus makes it possible to produce tanks having a relatively complex geometry, or on the contrary a relatively simple or even conventional geometry, for example a tank with a cylindrical envelope which can be intended for the aeronautics sector in order to store a large quantity of fuel.

The geometry and structure of the reinforcements 3 may be different from those described above. For example, the end parts of the reinforcements may have a concave or other shape of revolution. The central part of the reinforcements or all of their parts may have a square, hexagonal or other section. Furthermore, the reinforcements can be solid or include a filling material, unlike the well-type reinforcements which are described above.

The respective orientation of the reinforcements can also present numerous variations, whether in relation to one or more walls of the envelope to which they are connected or in relation to other reinforcements.

In terms of material, the envelope 2 and/or the reinforcements 3 may comprise another type of thermoplastic or another type of material, for example a thermosetting material or even a resin.

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 vehicle.

Claims (10)

Tank (1) for a transport device such as a motor vehicle, an aircraft or a boat, comprising a body which delimits a cavity (4) intended to contain a fluid, in particular a gas, the body comprising walls (5- 7) forming an envelope (2) of the tank (1), characterized in that the body comprises one or more reinforcements (3), each of the reinforcements (3) connecting two of said walls (5, 6) to each other ) arranged opposite each other. Tank (1) according to claim 1, in which the reinforcements (3) are integral with the envelope (2). Tank (1) according to claim 1 or 2, in which each of the reinforcements (3) has a connection direction (D4) along which it extends, the connection direction (D4) being preferably perpendicular or oblique by relative to one and/or the other of the walls (5, 6) which are connected to each other by this reinforcement (3). Tank (1) according to claim 3, in which each of the reinforcements (3) forms an external surface circumferentially closed around the direction of connection (D4), the entirety of this external surface preferably delimiting the cavity (4). Tank (1) according to claim 3 or 4, in which each of the reinforcements (3) forms an internal surface delimiting a hollow space (14), this hollow space (14) preferably defining an opening which passes through the tank (1) according to the connection direction (D4). Tank (1) according to any one of claims 3 to 5, in which the connection direction (D4) of one or more of said reinforcements (3) is perpendicular or oblique with respect to the connection direction (D3) of one or more other of said reinforcements (3). Tank (1) according to any one of claims 1 to 6, in which each of the reinforcements (3) comprises a first end portion (12) secured to one of said walls (5) which it connects, a second end part (13) integral with the other of said walls (6) which it connects and a central part (11) extending between the first end part (12) and the second end part (13 ), the first end part (12) and/or the second end part (13) each preferably having an increasing dimension going from the central part (11) towards the first wall (5, 6) to which it is respectively connected. Transport device such as a motor vehicle, an aircraft or a boat, comprising one or more tanks (1) according to any one of claims 1 to 7. Method of manufacturing a tank (1) according to any one of claims 1 to 7, comprising a step of assembling, for example by molding, elements of material so as to form a continuous extension of material between the envelope (2) and the reinforcement(s) (3). Method according to claim 9, in which the body of the tank (1) is manufactured in one piece.