Assembly for a tank, comprising an armature and an internal reinforcing element

Abstract

The invention relates to an assembly (10) for a plastic tank for a motor vehicle, comprising an armature (12) and an internal reinforcing element (14) of the tank fixed to the armature (12), the internal reinforcing element (14) having a length (L) extending along a longitudinal axis X and comprising a section referred to as an intermediate section (19) dividing the length (L) into two parts, the armature (12) comprising attachment means (15) for attaching the internal reinforcing element (14), wherein the attachment means (15) comprises a first hook (20) and a second hook (20); - the first hook (20) clasping an outer part (22) of the internal reinforcing element (14), at a first contact surface (24) provided on the first hook (20), the first contact surface (24) being borne by a base (26) of the first hook (20), a part (28) of which is flexible; - the second hook (20) clasping an outer part (22) of the internal reinforcing element (14), at a second contact surface (24) provided on the second hook (20), the second contact surface being borne by a base (26) of the second hook (20), a part (28) of which is flexible; - the first contact surface (24) and the second contact surface (24) being arranged, respectively, on either side of the intermediate section (19) of the internal reinforcing element; and - the base (26) of at least one of the hooks (20) bearing at least three ribs (30), the contact surface (24) of at least one of the hooks (20) being borne by the at least three ribs (30), ensuring contact with the outer part (22) of the internal reinforcing element (14), two ribs, referred to as "terminal" ribs (32), being located respectively at each end (34) of the hook (20).

Description

Tank assembly, including a frame and an internal reinforcement element

[0001] The invention relates to the technical field of plastic tanks for motor vehicles, more particularly liquid fuel tanks. The invention generally relates to an assembly comprising a frame and an internal tank reinforcement element attached to the frame, a tank comprising said assembly, and a method for manufacturing a plastic tank for motor vehicles.

[0002] Plastic fuel tanks obtained by blow molding from a parison undergo dimensional variations during their life, either firstly, as soon as they come out of the mold, due to their cooling which is accompanied by a shrinkage of the material, or during their use, due in particular to overpressure or underpressure inside the tank, or due to their thermal expansion during their life, or even due to their aging.

[0003] It is known to insert internal reinforcing elements within the tank during its manufacturing process. These internal reinforcing elements are intended to increase the resistance of the plastic tank to the mechanical stresses to which it is subjected during its lifespan.

[0004] The prior art is already known, notably from document WO2023031454, for a plastic tank assembly for motor vehicles, comprising a tank frame and an internal tank reinforcement element attached to the frame. The frame includes at least two structures, each partially enclosing or surrounding an outer portion of the internal reinforcement element. In this prior art assembly, the two structures have different internal circumferences. Consequently, attaching the reinforcement element to the frame is not straightforward. Furthermore, such a frame is not suitable for ensuring correct positioning of the internal reinforcement element within the tank when the tank is relatively tall, i.e., when its height exceeds 250 mm or 300 mm, for example, close to 400 mm.Indeed, for tanks manufactured by extrusion blow molding, the assembly is introduced into a parison in such a way as to position the internal reinforcement element horizontally. For a tall reinforcement element, this horizontal position can cause buckling of the internal reinforcement element, which can then, once mounted on the tank walls, present positional tolerance problems at the ends.

[0005] The invention aims in particular to provide an assembly whose manufacture is facilitated, while allowing for precise positioning of the reinforcement element relative to the walls of the tank.

[0006] To this end, the invention relates to a plastic tank assembly for a motor vehicle, comprising a frame and an internal tank reinforcement element attached to the frame. The internal reinforcement element has a length extending along a longitudinal axis X.The reinforcement includes a means for fixing the internal reinforcement element, in which the fixing means includes a first hook, and the first hook grips an outer part of the internal reinforcement element, at the level of a contact surface provided on the first hook, the first contact surface being supported by a base of the first hook, a part of which is flexible, - the base of the first hook has at least three ribs, the contact surface of the first hook being supported by the at least three ribs, ensuring contact with the outer part of the internal reinforcement element, two ribs of which, called "terminal", are located each at one end of the hook.

[0007] Thus, the first contact surface has a cross-section (with reference to the longitudinal direction of the internal reinforcement element) studded with ribs on the inside, the apexes of which point towards the outside of the internal reinforcement element. It is understood that the first contact surface is discontinuous; it is formed by the junction of the contact surfaces of the ribs of the first hook. More precisely, the first contact surface is formed by the junction of the contact surfaces of the apexes of the ribs of the first hook, these apexes being in contact with the outside of the internal reinforcement element.

[0008] The flexible part of the base of the first hook gives the contact surface an elasticity which allows the internal reinforcement element to be mounted easily and reliably in the hook.

[0009] Furthermore, thanks to the ribs, the contact surface can be easily adapted to the cross-section of the internal reinforcement element. Indeed, adapting the contact surface to the cross-section of the internal reinforcement element simply requires modifying the width of the ribs, which necessitates only minor modifications to the mold used to manufacture the hook. The width of a rib corresponds to the dimension of the rib in a direction perpendicular to the longitudinal axis X, measured from the base of the hook to the end of the rib that makes contact with the outer part of the internal reinforcement element. Thus, the presence of the ribs is particularly advantageous from a mold manufacturing cost perspective, especially when it is necessary to accommodate reinforcement elements of different diameters.

[0010] The term "tank" refers to a sealed reservoir suitable for storing liquid fuel under various operating and environmental conditions. The tank according to the invention is made with a plastic wall, generally comprising an inner face on its concave portion and an outer face on its convex portion. Preferably, the tank is a plastic tank designed for liquid fuel.

[0011] The term "hook" refers to a structure configured to partially surround the internal reinforcement element, with an opening in the hook to allow the insertion of the internal reinforcement element. It is understood that, thanks to the flexible section, this opening can be enlarged to facilitate the insertion of the internal reinforcement element. It is also understood that the opening can be very small, in the form of a slit, in its resting state, that is, when the flexible section is not elastically deformed.

[0012] The expression "hook gripping an outer part of the internal reinforcement element" refers to the fact that the hook comes into contact with an outer part of the internal reinforcement element and exerts pressure on it. In other words, the hook is always under tension against the internal reinforcement element.

[0013] The expression, "internal reinforcement element", refers to a structural element assembled, for example welded, at its two longitudinal ends to the plastic tank in order to limit the deformation of the tank when it is pressurized.

[0014] The frame is a structural support for the tank. Generally, the frame supports functional elements of the tank, such as attachment points for an internal reinforcement element, or even a sensor, a noise reduction element, a ventilation or fuel line, or a valve. By supporting the internal reinforcement element, it can help increase the resistance of the plastic tank to the mechanical stresses it is subjected to during its service life, particularly in the event of overpressure or underpressure within the tank.

[0015] The hook base is a part of the hook designed to surround the outer portion of the internal reinforcing element that the hook secures. The hook base carries the ribs that ensure contact with the internal reinforcing element. In one embodiment, the hook base comprises two flexible arms connected by a rigid core, the rigidity being proportional to the flexibility of the arms. In another embodiment, the hook could have a single flexible part, the other part being rigid; for example, the hook could have a shape similar to a question mark.

[0016] It is understood that the hook has two free ends that spread apart to allow the insertion of the internal reinforcing element. The term "end of the hook" refers to one of these two free ends.

[0017] In general, the assembly is configured to be fixed inside a plastic tank for a motor vehicle.

[0018] The contact surface may include up to eight ribs, or it may include five ribs. Preferably, it includes at least four ribs, more preferably five ribs, and even more preferably six ribs.

[0019] Preferably, at least one transverse plane passing through all the ribs can be defined, which allows for proper positioning of the reinforcement along the axis. Even more preferably, all the ribs extend to the same height from the base of the hook.

[0020] Advantageously, the ribs are equidistant along the base of the hook.

[0021] Depending on other optional features of the plastic tank assembly for motor vehicles, taken alone or in combination:

[0022] - The fastening means further includes a second hook clamping an outer part of the internal reinforcing element, at a second contact surface provided on the second hook, the second contact surface being supported by a base of the second hook, part of which is flexible. It is understood that the first hook and the second hook are two distinct elements. Preferably, the base of the second hook has at least three ribs, the contact surface of the second hook being supported by at least three ribs, ensuring contact with the outer part of the internal reinforcing element, two of whose ribs, called "terminal" ribs, are located at each end of the hook.

[0023] The internal reinforcement element comprises an intermediate section dividing its length (L) into two parts: a first contact surface and a second contact surface. These two parts provide the total contact surface of the fastening means, and the total contact surface is located on either side of the intermediate section of the internal reinforcement element. It is understood that the expression "the total contact surface is located on either side of the intermediate section" refers to the case where the total contact surface is composed of two separate parts, each part located on a different side of the intermediate section. It is understood that when the fastening means comprises a first hook and a second hook, the first and second contact surfaces are located on either side of the intermediate section of the internal reinforcement element, respectively.The total contact surface can consist of a single continuous portion, this continuous portion extending beyond the intermediate section on each side. It is understood that when the fastening means comprises only the first hook, i.e., does not include a second hook, the first contact surface is located on either side of the intermediate section. Preferably, the two spaces (that of the first hook and that of the second hook) are aligned along the longitudinal axis X, and the internal reinforcing element is inserted into the hook along its transverse direction through the opening thus formed.The two spaces can also be arranged in a non-aligned manner, for example, staggered with respect to the longitudinal axis X. The insertion of the internal reinforcement element into the hook is then achieved by pivoting the internal reinforcement element around an axis perpendicular to the longitudinal axis X, located at the intermediate section. Preferably, the intermediate section is a central section dividing the length of the internal reinforcement element into two equal parts. The central section of the internal reinforcement element lies in a median transverse plane of the internal reinforcement element. It generally includes the center of gravity of the internal reinforcement element.Thus, since the first and second contact surfaces are positioned on either side of the central section, preferably symmetrically with respect to the center of gravity, the hooks allow the internal reinforcement element to be held on either side of its center of gravity. The same applies when the fastening method consists of only one hook. This is particularly advantageous when the reinforcement element must be held horizontally, for example, when it is inserted into a parison during the extrusion blow molding process of the tank. It is also advantageous for limiting the movement of the internal reinforcement element in planes parallel to the weld surfaces once it has been installed in the tank. This avoids positional tolerance problems with the internal reinforcement element.

[0024] - The terminal ribs protrude from the base of the hook due to a depression in the hook's base. This gives the terminal rib a distinctive structure, forming, for example, a "V". The depression in the hook's base provides the terminal rib with additional elasticity, facilitating the insertion of the internal reinforcement element into the hook and locking the hook onto the outer part of the internal reinforcement element via a snap-fit ​​mechanism.

[0025] - the base of the first hook and the base of the second hook, when the fastening means includes a second hook equipped with ribs as described above, shall have at least four ribs each, each of said hooks further includes a hollow intermediate body carrying the base of said hook and attaching the base of said hook to a main body of the frame, the hollow intermediate body being delimited by at least four walls, one of the walls corresponding to a first portion of the base of said hook, and two ribs among the at least four ribs, distinct from the terminal ribs, project from the base of said hook from said first portion, the two ribs being positioned in the extension of two walls of the hollow intermediate body, said two walls of the intermediate body being perpendicular to the first portion of the base of said hook.Thus, the base of the hook, one of the two ribs, and one of the perpendicular walls form a particular structure, namely the intersection of the base of the hook and the perpendicular wall extended by the rib. This structure makes it possible to stiffen the first portion. In an example, the first portion of the base of the hook corresponds to the rigid web of the base of the hook.

[0026] Each contact surface has a height extending along the longitudinal axis X, such that the height is greater than or equal to 5 mm (millimeters). Since each hook grips the internal reinforcement element to a height greater than or equal to 5 mm, the contact height between the reinforcement and the internal reinforcement element ensures particularly precise positioning of the reinforcement element relative to the tank walls. In effect, the hook's height forms a kind of sheath that ensures a particularly precise orientation of the internal reinforcement element, so that it extends perfectly perpendicular to the tank walls. This sheath function is particularly relevant for correctly holding a very elongated internal reinforcement element, the height of which can reach up to 400 mm. The assembly according to the invention can therefore be used in a tank with a height of up to 400 mm.Increasing the clamping height further improves the retention of the internal reinforcement element. However, a clamping height of 25 mm or less limits the amount of material used in the reinforcement's manufacture. If the fastening method does not include a second hook, the first hook advantageously provides a clamping height of approximately 30 mm. The term "height" refers to a distance measured along an axis parallel to the central longitudinal axis of the internal reinforcement element. Therefore, if the cross-section of the internal reinforcement element varies along the longitudinal axis, the height does not correspond precisely to a length measured across the surface of the internal reinforcement element. In other words, when the internal reinforcement element is installed in the tank, the height is measured along an axis perpendicular to the weld surface.It should be noted that the two 5 mm hooks are sufficient to ensure proper support and guidance of the internal reinforcement element. Advantageously, the fastening means comprises precisely two hooks, and only two, gripping the internal reinforcement element. In other words, preferably, the reinforcement is not provided with any additional means for supporting or guiding the internal reinforcement element. Preferably, the height of the contact surface can reach 25 mm, and more preferably, the height is approximately 15 mm. Advantageously, the contact surfaces of the two hooks have the same height, which ensures that the internal reinforcement element is held in a balanced position along its height.

[0027] - The internal reinforcement element includes, for each hook, at least one axial stop protrusion, so as to block translational movement in the direction of the longitudinal axis X of the internal reinforcement element relative to the reinforcement. Thus, the internal reinforcement element has its translational movement blocked relative to the reinforcement in a direction perpendicular to the weld surface. The hooks clamping the internal reinforcement element are preferably positioned symmetrically with respect to the center of gravity of the internal reinforcement element. The protrusions project from the outer surface of the internal reinforcement element such that the two protrusions prevent the relative axial movement of the hooks in two opposite directions, which makes it possible to immobilize the internal reinforcement element relative to the reinforcement.To achieve this, the protrusions can be located either both between the two reinforcement hooks or both outside the reinforcement hooks. By butting the two hooks together, the axial positioning of the internal reinforcement element relative to the reinforcement is secured. Advantageously, the protrusions are not located in areas of high stress and therefore do not weaken the internal reinforcement element. Advantageously, at least one protrusion is shaped like a collar, which allows the buttress forces to be distributed around the central longitudinal axis of the internal reinforcement element. Preferably, both protrusions are each shaped like a collar. The collar can be solid, i.e., continuous. It can also include recesses, i.e., be discontinuous.

[0028] The assembly for a plastic automotive tank has an axial clearance between the protrusion and the corresponding hook of between 0 and 5 mm. This effectively maintains the relative axial positioning of the frame and the internal reinforcement element. A clearance greater than 0.5 mm, or even 1 mm, is particularly advantageous as it facilitates the mounting of the internal reinforcement element onto the frame. Preferably, the axial clearance is between 0.5 mm and 2 mm, and even more preferably, close to 1 mm.

[0029] Each hook clamps the outer portion of the internal reinforcement element at an angle of 240° or greater. Compared to a smaller angle, this clamps the internal reinforcement element over a significant portion of its outer surface, allowing the hook to close more securely around the reinforcement element and thus providing better support. This is particularly advantageous for tall internal reinforcement elements. Consequently, the internal reinforcement element is better supported during tank manufacturing and subsequent tank operation. Preferably, the angle can reach 340°, and more preferably, it is approximately 320°.

[0030] The fastening means includes a second hook, and the two hooks are separated by a distance of at least 60 mm. Thus, when each hook extends to a minimum height of 5 mm, the internal reinforcement element is held by the fastening means to a minimum height of 70 mm, which corresponds to slightly more than 1 / 6 of the height of a 400 mm pillar. This support, which is exerted around the intermediate section and generally around the center of gravity of the internal reinforcement element, is sufficient to ensure that the 400 mm internal reinforcement element remains horizontal, particularly when the reinforcement element is introduced into the parison during the extrusion blow molding process of the tank. This is also advantageous for limiting the movement of the internal reinforcement element in planes parallel to the weld surfaces once it has been installed in the tank.Increasing the distance improves the retention. However, a maximum distance of 200 mm is sufficient to ensure retention. Furthermore, limiting the distance to 200 mm reduces the amount of material used to manufacture the fastening device, thus limiting the overall weight and size of the frame, and consequently, the overall weight of the tank containing it. Preferably, the distance is approximately 120 mm.

[0031] The height of each contact surface is approximately 15 mm, and the distance between the two hooks is approximately 120 mm. Thus, the internal reinforcement element is held by the fastener over a height of approximately 150 mm, which is slightly more than one-third of the height of a 400 mm pillar. These values ​​represent a good compromise for achieving adequate support while minimizing the amount of material required to manufacture the fastener.

[0032] The fastening means includes a second hook, and the internal reinforcement element has the general shape of a solid of revolution, preferably a cylinder or a diabolo, and includes a zone of mechanical weakness located between its two outer parts held together by the hooks. This prevents the zone of mechanical weakness from being reinforced by being held within the fastening means. The zone of mechanical weakness is designed to cause the internal reinforcement element to break when subjected to high stresses from forces exerted on the tank, thus preventing tank rupture. This zone of mechanical weakness takes the form of a smaller cross-section, at least one notch / slit, or a reduced wall thickness.

[0033] In one embodiment, the area of ​​mechanical weakness coincides with the central section.

[0034] - The internal reinforcement element is a diabolo shape, and the ribs have a width that varies in height, so as to engage in a form-based cooperation with the diabolo. Thus, the diabolo is optimally held by the fastening means.

[0035] The internal reinforcing element includes a shape capable of imposing its orientation within the assembly; that is, this shape is configured to impose its orientation within the assembly. In other words, the internal reinforcing element includes a keying feature. This keying feature preferably corresponds to a shape on the outer part of the internal reinforcing element that imposes a limited number of radial directions in which the internal reinforcing element can be inserted into the hook, preferably only one or two radial directions. This shape is, for example, a flat surface or an indexing hole configured to cooperate with a pin of the fastening means. Advantageously, the shape corresponds to a radial projection.The shape can, for example, be a finger projecting radially from the outer part of the internal reinforcing element, uniquely designed to fit inside the hook opening defined by its free ends when the finger and the opening are radially aligned. Advantageously, each protrusion has two coaxial fingers oriented on either side of the outer surface of the internal reinforcing element.

[0036] - The length of the internal reinforcement element is between 250 and 400 mm, preferably between 300 and 400 mm.

[0037] - The height of the total contact surface is between 5 and 50 mm, preferably between 10 and 40 mm, more preferably between 25 and 35 mm, preferably about 30 mm.

[0038] The ratio of the height of the total contact surface to the length of the internal reinforcement element varies between 1 / 80 and 1 / 3 preferably between 3 / 80 and 1 / 10 preferably about 3 / 40, or about 3 / 80.

[0039] The frame and / or fastening system consists of several assembled parts. This allows for the production of a frame by molding, the dimensions of which are not limited by molding capabilities. Therefore, there is no limitation on the distance between the two hooks securing the internal reinforcement element, and this element can be held in optimal condition, even if it is tall.

[0040] The invention also relates to a plastic tank for a motor vehicle comprising an assembly as described above. Preferably, the internal reinforcing element is welded to the plastic tank at both ends.

[0041] The invention also relates to a method for manufacturing a plastic tank for a motor vehicle comprising a step of attaching an internal reinforcement element to a frame to obtain an assembly as described above. Brief description of the figures

[0042] The invention will be better understood upon reading the following description, given solely by way of example and made with reference to the accompanying drawings in which:

[0043] is a perspective view of a plastic tank assembly for a motor vehicle according to an embodiment of the invention;

[0044] is a perspective view from a different angle of the whole represented on the;

[0045] is a partial schematic longitudinal section view of an internal reinforcement element and two reinforcement hooks of the assembly shown on the;

[0046] is a cross-sectional view of an internal reinforcing element and a reinforcing hook of the assembly shown on the;

[0047] is a cross-sectional view of a reinforcement hook of the assembly shown on the;

[0048] is a front perspective view of a fastening means in the assembly shown on the;

[0049] is a front perspective view of a plastic tank assembly for a motor vehicle according to a second embodiment of the invention;

[0050] is a perspective view of the whole shown on the, before fixing the internal reinforcement element to the frame;

[0051] is a partial rear side view of the laau at the hook level;

[0052] is a partial front side view of the hook;

[0053] is a cross-sectional view according to plan XI-XI of the assembly for a plastic tank for a motor vehicle;

[0054] is a cross-sectional view similar to the cross-section of, an assembly in which the internal reinforcing element is not oriented in such a way as to allow its attachment in the reinforcement. Detailed description

[0055] Figures 1 and 2 show an assembly for a plastic tank for a motor vehicle according to a first embodiment of the invention, designated by the general reference numeral 10. The assembly 10 comprises a frame 12 and internal tank reinforcement elements 14 attached to the frame 12. The internal reinforcement element 14 is intended to connect two opposing walls of the plastic tank (not shown). It is assembled, for example by welding, at weld surfaces 13 located at its two longitudinal ends, to the plastic tank. The frame 12 includes a fastening means 15 (visible in the figure) for the internal reinforcement element 14. It also includes a deformable link 16 connecting the frame 12 and the fastening means 15. The deformable link 16 can deform to allow relative movement of the frame 12 and the fastening means 15.The frame also includes a receiving member 17 (visible in the figure) for receiving an insertion means such as an insertion rod for inserting the assembly 10 into a parison during tank manufacturing. The frame 12 also includes a support means 18 for tank components such as a pump, a level sensor, a pressure sensor, a temperature sensor, and a valve such as a check valve, a Roll Over Valve (ROV), or a Fill Limit Vent Valve (FLVV), or for venting and fuel lines. The support means 18 can act as a reinforcement element when the tank is under pressure relative to atmospheric pressure. It is generally welded to the upper wall of the tank and can be positioned as a counter-support on the lower wall of the tank.The frame 12 also carries a retention 21, providing a reinforcement function for the tank, which is intended to be welded to the upper and lower walls of the tank.

[0056] Each internal reinforcement element 14 has a visible length L extending along a longitudinal axis X and includes an intermediate section 19 dividing the length L into two parts. In the embodiment shown, the length L is between 250 and 400 mm. The fastening means 15, visible in the figure, comprises a first hook 20 and a second hook 20, arranged one above the other with respect to the direction of the longitudinal axis X. The first hook 20 grips an outer portion 22 of the internal reinforcement element 14, visible in the figure. As can be seen in particular in the figure, the first hook 20 grips the internal reinforcement element 14 at a first contact surface 24 formed on the first hook 20.Similarly, the second hook 20 grips an outer portion 22 of the internal reinforcing element 14, visible in Figure 1, at a second contact surface 24, shown in Figure 2, formed on the second hook 20, namely the lower hook. As seen in Figure 1, the first contact surface 24 is supported by a base 26 of the hook 20, a portion 28 of which is flexible. The same is true for the second contact surface 24. The hook 20 has two free ends 34 that spread apart to allow the insertion of the internal reinforcing element 14. Each of these ends is called a "hook end." These free ends 34 thus define a space forming an opening in each hook 20 to allow the insertion of the internal reinforcing element 14 into each hook 20.In the example shown here, the spaces of the first and second hooks are aligned along the longitudinal axis X, allowing the internal reinforcement to be inserted into the hooks by translation in a direction perpendicular to the longitudinal axis X. As can be seen in the figure, the first contact surface 24 and the second contact surface 24 provide a total contact surface of the fastening means 15, and the total contact surface is located on either side of the intermediate section 19. The first and second contact surfaces 24 are also located respectively on either side of the intermediate section 19 of the internal reinforcement element 14.The base 26 of at least one of the hooks 20 has at least three ribs 30, clearly visible in figures 4 to 6, the contact surface 24 of at least one of the hooks 20 being supported by the at least three ribs 30, ensuring contact with the outer part 22 of the internal reinforcing element 14. Two of these ribs, called "terminal" ribs 32, are each located at one end 34 of the hook 20. The end 34 of the hook is located in a plane parallel to the longitudinal axis X.

[0057] In figures 4 to 6, the contact surface 24 comprises six ribs 30, including two terminal ribs 32. All the ribs 30 pass through at least one of the same transverse plane, and all the ribs 30 extend over the same height h, visible on the, of the base 26 of the hook 20. The ribs 30 are distributed equidistantly along the base 26 of the hook 20.

[0058] As shown in Figure 1, the ribs 30 have a width l corresponding to the rib dimension in a direction perpendicular to the longitudinal axis X, measured from the base 26 of the hook 20 to the end of the rib that makes contact with the outer part 22 of the internal reinforcing element 14. The contact surface 24 has a height h measured along the longitudinal axis X of the internal reinforcing element. The height h is measured along an axis perpendicular to the weld surface 13, visible with the internal reinforcing element 14 in Figures 1 and 2. In the embodiment shown, the height h is greater than or equal to 5 mm, and the contact surfaces 24 of the two hooks 20 have the same height h. The height h is approximately 15 mm. Thus, the two hooks 20 provide a total contact surface with a height of approximately 30 mm.The two hooks 20 are separated by a distance d of at least 60 mm, which is approximately 120 mm in the embodiment shown. The ratio of the height h of the total contact surface to the length L of the internal reinforcing element 14 varies in the embodiment shown between 3 / 40 and 3 / 25. For a total contact surface height of 10 mm, it would vary between 1 / 40 and 1 / 25, and for a total contact surface height of 50 mm, it would vary between 1 / 8 and 1 / 5. Preferably, the ratio varies between 3 / 40 and 1 / 10, and even more preferably, it is approximately 3 / 40.

[0059] In the embodiment shown, the base 26 of the hook comprises two flexible arms 35 connected to each other by a core 36, which is rigid in comparison to the arms 35. Thus, the arms 35 are a flexible part 28 of the base 26. More precisely, in the embodiment shown, the core 36 is straight and the arms 35 have a general shape in the form of a circular arc.

[0060] In the embodiment shown, and as can be seen in particular in Figures 4 and 5, the terminal ribs 32 project from the base 26 of the hook 20 due to a depression 37 in the base 26 of the hook 20. Thus, the terminal rib 32 has a particular structure, forming, for example, a "V". The depression 37 in the base 26 of the hook 20 provides the terminal rib 32 with additional elasticity, which facilitates the insertion of the internal reinforcing element 14 inside the hook 20, and locks the hook 20 onto the outer part 22 of the internal reinforcing element 14, visible in Figure 5, by means of a snap-fit.

[0061] In the embodiment shown, the base 26 has at least four ribs 30, and the hook 20 further comprises a hollow intermediate body 38, visible in particular in Figures 4 to 6, which supports the base 26 of the hook 20 and connects the base 26 of the hook 20 to a main body 40 of the frame 12, visible in particular in Figures 1, 2, 5, and 6. The hollow intermediate body 38 is delimited by at least four walls 42. One of the walls corresponds to a first portion 44 of the base 26 of the hook 20. Two ribs 46, visible in particular in Figures 4 and 5, among the at least four ribs 30, distinct from the terminal ribs 32, project from the base 26 of the hook 20 from said first portion 44. The two ribs 46 are positioned in line with two walls 48 of the hollow intermediate body 38, and said two walls 48 of the hollow intermediate body 38 are perpendicular to the first portion 44 of the base 26 of the hook 20.In the embodiment shown, the first portion 44 corresponds to the rigid core 36 of the base of the hook 20.

[0062] In the embodiment shown, the internal reinforcing element 14, visible in particular in Figures 1 to 3, has the general shape of a solid of revolution, more precisely a diabolo, and it includes a zone of mechanical weakness 50, located between its two outer parts 22, visible in particular in Figures 1 and 3, held together by the brackets 20. The zone of mechanical weakness 50 here has the shape of a weaker section. In the internal reinforcing element 14 shown, the intermediate section 19 is a central section, dividing the length L of the internal reinforcing element 14 into two parts of equal length. The central section 19 of the internal reinforcing element 14 is located in a median transverse plane of the internal reinforcing element 14. It includes the center of gravity of the internal reinforcing element 14.As can be seen in Figure 1, the two hooks 20 are arranged respectively on either side of the central section 19, symmetrically with respect to the center of gravity. In the internal reinforcing element 14 shown, the zone of mechanical weakness 50 coincides with the central section 19. As can be seen in Figures 5 and 6, the ribs 30 have a width l that varies in height h from a width l1 to a width l2, so as to exert a form cooperation with the diabolo 14.

[0063] In the embodiment shown, the internal reinforcing element 14 comprises, for each hook 20, a protrusion 52, visible in particular in Figure 1, forming an axial stop, so as to prevent translational displacement in the direction of the longitudinal axis X of the internal reinforcing element 14 relative to the reinforcement whose hooks 20 are shown. In this embodiment, the protrusions 52 are located outside the hooks 20 of the reinforcement 12. It should be noted that the protrusions 52 are not located at the level of the area of ​​mechanical weakness 50, and therefore do not weaken the internal reinforcing element. The protrusions 52 have the shape of a solid collar, visible in Figure 1. The assembly 10, shown in Figures 1 and 2, has an axial clearance 54 between the protrusion 52 and the hook 20, shown in Figure 1. The axial play 54 is approximately 1 mm here.

[0064] On the, we see that the hook 20 clamps the outer part of the internal reinforcement element (not shown on the), at an angle α greater than or equal to 240°, more precisely here of about 320°.

[0065] Figures 7 to 11 show an assembly for a plastic fuel tank for a motor vehicle according to a second embodiment of the invention. In these figures, elements similar to those in the preceding figures are designated by identical reference numerals.

[0066] In the embodiment shown in Figures 7 to 11, the internal reinforcing element has a cross-sectional shape; it does not have the general shape of a solid of revolution. In this second embodiment, the fastening means comprises a single hook, namely a first hook 20. The first contact surface 24 is arranged on either side of the intermediate section 19. As can be seen, for example, in the figure, in which the internal reinforcing element 14 is not fixed to the reinforcement, the contact surface 24 comprises five ribs 30, including two terminal ribs 32. The ribs 30 are equidistant along the base 26 of the hook 20.

[0067] In the internal reinforcement element 14 shown, the intermediate section 19 is a central section, dividing the length L of the internal reinforcement element 14 into two equal parts. In the embodiment shown, the length L is between 250 and 400 mm. The central section 19 of the internal reinforcement element 14 is located in a median transverse plane of the internal reinforcement element 14. It includes the center of gravity of the internal reinforcement element 14. The hook 20 is arranged on either side of the central section 19, symmetrically with respect to the center of gravity. In the embodiment shown, the height h of the contact surface 24 is greater than or equal to 5 mm. The height h is approximately 30 mm. The ratio of the height h of the total contact surface to the length L of the internal reinforcement element 14 varies in the embodiment shown between 3 / 80 and 3 / 25.For a total contact surface height of 5 mm, it would vary between 1 / 80 and 1 / 50, and for a total contact surface height of 30 mm, it would vary between 3 / 40 and 3 / 25. Preferably, the ratio varies between 3 / 40 and 1 / 10, preferably still, it is about 3 / 40.

[0068] In this embodiment, the protrusions 52 of the internal reinforcing element 14 are located outside the hook 20 of the reinforcement 12. These protrusions 52 form an axial stop, so as to prevent translational displacement in the direction of the longitudinal axis X of the internal reinforcing element 14 relative to the reinforcement 12. In this embodiment, the internal reinforcing element 14 includes two protrusions 52 for the hook 20. The assembly 10 has an axial clearance between the protrusion 52 and the hook 20, not visible in the figures. The axial clearance is approximately 1 mm.

[0069] Hook 20 clamps the outer part of the internal reinforcement element at an angle α not shown, greater than or equal to 240°, more precisely here of about 320°.

[0070] In the embodiment of the invention shown in Figures 7 to 11, the internal reinforcing element 14 comprises a shape 56 adapted to impose its orientation within the assembly 10, or a keying device. The shape 56 is a finger projecting radially from the outer portion 22 of the internal reinforcing element 14. The finger 56 is able to insert into the opening of the hook 20 defined by its free ends 34 only when the finger and the opening are radially aligned, as shown, for example, in Figure 11. When the finger 56 and the opening are not aligned, as shown in Figure 11, the finger 56 cannot insert into the opening of the hook 20. In this configuration, the internal reinforcing element 14 cannot be inserted into the hook 20.

[0071] In figures 7 to 12, each protrusion 52 carries two coaxial fingers 56 oriented on either side of the external surface 22 of the internal reinforcing element 14.

[0072] In the embodiment shown in figures 7 to 11, the internal reinforcing element 14 comprises a structure made of continuous fibers coated with a polymer matrix.

[0073] The manufacturing process for a plastic fuel tank for a motor vehicle includes a step of attaching the internal reinforcing element 14 to the frame 12 to obtain the assembly 10 described above. This attachment is achieved by inserting the internal reinforcing element into each hook. Once the frame is fitted with the internal reinforcing element 14 and any other functional elements, the assembly is placed in a parison that defines the tank walls, specifically the upper and lower walls. The mold is then closed onto the parison to form the tank, and certain elements, including the internal reinforcing element 14, are welded to the tank walls.

[0074] The invention is not limited to the embodiments shown and other embodiments will be obvious to a person skilled in the art. List of references

[0075] 10: Assembly for plastic tank 12: Reinforcement 13: Weld surface 14: Internal reinforcement element 15: Fastening means 16: Deformable link 17: Receiving element for an insertion means 18: Support means 19: Intermediate section 20: Hook 21: Retention 22: Outer part of the internal reinforcement element 24: Hook contact surface 26: Hook base 28: Flexible part of the base 30: Rib 32: Terminal rib 34: Hook end 35: Base arm 36: Base core 37: Base depression 38: Hollow intermediate body 40: Main body 42: Wall of the hollow intermediate body 44: First portion 46: Rib on the first portion 48: Wall perpendicular to the first portion 50: Area of ​​mechanical weakness 52: Protrusion 54: Axial clearance 56: Keying device

Claims

Assembly (10) for a plastic tank for a motor vehicle, comprising a frame (12) and an internal tank reinforcement element (14) attached to the frame (12), the internal reinforcement element (14) having a length (L) extending along a longitudinal axis X, the frame (12) comprising a fastening means (15) for the internal reinforcement element (14), wherein the fastening means (15) comprises a first hook (20), and the first hook (20) grips an outer portion (22) of the internal reinforcement element (14) at a first contact surface (24) formed on the first hook (20), the first contact surface (24) being supported by a base (26) of the first hook (20), a portion (28) of which is flexible, the assembly (10) being characterized in that the base (26) of the first hook (20) has at least three ribs (30), the contact surface (24) of the first hook (20) being supported by at least three ribs (30),ensuring contact with the outer part (22) of the internal reinforcing element (14), two ribs of which, called "terminal" (32), are located each at one end (34) of the hook (20). Assembly (10) according to the preceding claim, the fastening means (15) further comprising a second hook (20) clamping an outer part (22) of the internal reinforcement element (14), at the level of a second contact surface (24) provided on the second hook (20), the second contact surface (24) being supported by a base (26) of the second hook (20) a part (28) of which is flexible, and preferably, the base (26) of the second hook (20) has at least three ribs (30), the contact surface (24) of the second hook (20) being supported by the at least three ribs (30), ensuring contact with the outer part (22) of the internal reinforcement element (14) two ribs of which, called "terminal" (32), are located each at one end (34) of the second hook (20). Assembly (10) according to claim 2, wherein the first hook (20) and the second hook (20) are separated by a distance (d) of at least 60 mm. Assembly (10) according to claim 2 or 3, wherein the internal reinforcement element (14) comprises an intermediate section (19) cutting the length (L) of the internal reinforcement element (14) into two parts, the first contact surface and the second contact surface providing a total contact surface of the fastening means, and the total contact surface is disposed on either side of the intermediate section of the internal reinforcement element (14). Assembly (10) according to any one of the preceding claims, wherein the terminal ribs (32) project from the base (26) of the first hook (20) and from the base (26) of the second hook (20), where the fastening means (15) comprises a second hook (20) equipped with ribs (30) according to claim 2, following a depression (37) in the base (26) of said hook (20). Assembly (10) according to any one of the preceding claims, wherein the base (26) of the first hook (20) and the base (26) of the second hook (20), where the fastening means (15) comprises a second hook (20) equipped with ribs (30) according to claim 2, each has at least four ribs (30), each of said hooks (20) further comprising a hollow intermediate body (38) carrying the base (26) of said hook (20) and attaching the base (26) of said hook (20) to a main body (40) of the frame (12), the hollow intermediate body (38) being delimited by at least four walls (42), one of the walls (42) corresponding to a first portion (44) of the base (26) of said hook (20), and two ribs (46) among the at least four ribs (30), distinct from the terminal ribs (32), project from the base (26) of said hook (20) from said first portion (44),the two ribs (46) being positioned in line with two walls (48) of the hollow intermediate body (38), said two walls (48) of the intermediate body being perpendicular to the first portion (44) of the base of said hook (20). Assembly (10) according to any one of the preceding claims, wherein each contact surface (24) has a height (h) extending along the longitudinal axis X, such that the height (h) is greater than or equal to 5 mm. Assembly (10) according to any one of the preceding claims, wherein the internal reinforcement element (14) comprises for the first hook (20), and for the second hook when the fastening means (15) comprises a second hook, at least one protrusion (52) forming an axial stop, so as to block translational displacements in the direction of the longitudinal axis X of the internal reinforcement element (14) relative to the reinforcement (12). Assembly (10) according to the preceding claim, such that it has an axial clearance (54) between the protrusion (52) and said corresponding hook (20) of between 0 and 5 mm (millimeters). Assembly (10) according to any one of the preceding claims, wherein each of the first hook (20), and second hook (20) when the fastening means (15) includes a second hook (20) clasps the outer part (22) of the internal reinforcing element (14) at an angle (α) greater than or equal to 240°. Assembly (10) according to claim 7 taken in combination with claim 3, wherein the height (h) of each contact surface (24) is about 15 mm, and the distance (d) separating the two hooks (20) is about 120 mm. Assembly (10) according to any one of the preceding claims, wherein the internal reinforcing element (14) comprises a shape configured to impose its orientation in the assembly. Assembly (10) according to claim 2 taken in combination with any one of claims 3 to 12, wherein the internal reinforcing element (14) has the general shape of a solid of revolution, preferably a cylinder or a diabolo, and it includes a zone of mechanical weakness (50) located between its two outer parts (22) held together by the hooks (20). Assembly (10) according to the preceding claim, wherein the internal reinforcing element (14) is a diabolo, and the ribs (30) have a width (l) which varies in height (h), so as to exert a form cooperation with the diabolo (14). Assembly (10) according to any one of the preceding claims, wherein the frame (12) and / or the fastening means (15) consists of several assembled parts. Plastic tank for motor vehicle comprising an assembly (10) according to any one of the preceding claims. Method of manufacturing a plastic tank for a motor vehicle comprising a step of attaching an internal reinforcement element (14) to a frame (12) to obtain an assembly (10) according to any one of claims 1 to 15.

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