FR3086928A1 - FLUID TANK, ESPECIALLY FOR USE IN A MOTOR VEHICLE - Google Patents

Abstract

The invention relates mainly to a fluid reservoir (10), in particular intended for use in a motor vehicle, comprising: a body (11) made of a polymer material, said body (11) delimiting a space for filling with a fluid, and -a stiffening insert (12, 12 '), characterized in that the stiffening insert (12, 12') is made of a polymer material reinforced with fibers, said stiffening insert (12, 12 ' ) being overmolded on at least one wall of said tank body (11) (10).

Description

FLUID RESERVOIR, IN PARTICULAR FOR USE IN A MOTOR VEHICLE The present invention relates to a fluid reservoir, in particular intended for use in a motor vehicle. The invention finds a particularly advantageous, but not exclusive, application with fuel tanks, depollution liquid tanks, in particular for selective catalytic reduction systems (SCR system, acronym for Selective Catalytic Reduction in English), fuel additives, in particular diesel, windshield washer tanks, engine coolant tanks, or any other type of tank that can be used in the automotive industry.

In a manner known per se, a tank comprises a body made of a polymer material delimiting a space for filling with a fluid, as well as stiffening inserts made of steel allowing the tank to be fixed to a structural element, in particular the body. of the vehicle.

However, the presence of steel inserts to support the tank has the disadvantage of significantly increasing the weight and size of the assembly, and requiring the performance of a fastening operation of the inserts on the body of the tank, for example by means of screws or rivets. It is also necessary to carry out anticorrosion protection (zincing and / or painting) to avoid corrosion problems.

There are also significant design constraints, insofar as the connection zones between the steel insert and the tank body, must necessarily pass through the joint plane of the tank which is a robust zone of double thickness. of parison. In addition, the useful volume of the tank is not optimized, because the ribbed insert is not pressed perfectly on the tank.

At the end of the vehicle's life, when it is dismantled, the tank requires dismantling of the steel insert because the two materials (steel and polymer) have different recycling channels.

The invention aims to effectively remedy the aforementioned drawbacks by proposing a fluid reservoir, in particular intended for use in a motor vehicle, comprising:

a body made of a polymer material, the body defining a space for filling with a fluid, and

- A stiffening insert, characterized in that the stiffening insert is made of a polymer material reinforced with fibers, the stiffening insert being overmolded on at least one wall of the tank body.

The invention thus allows, by replacing the metal insert with an insert made of polymer material, to strengthen the mechanical strength of the tank while considerably reducing the overall weight. The invention also makes it possible to dispense with the operation of depositing an anticorrosion protection layer as well as design constraints linked to the use of steel inserts. In fact, the invention makes it possible to reassemble the interface for fixing to the body in a zone higher than the joint plane of the tank. In addition, the invention makes it possible to increase the useful volume of the reservoir, by optimizing the thickness of the insert-wall assembly of the reservoir. The invention also facilitates recycling of the tank, since it is no longer necessary to dismantle the steel inserts at the end of the vehicle's life.

In one embodiment, the fibers are continuous.

In one embodiment, the stiffening insert is formed by several layers of a ribbon superimposed on each other.

In one embodiment, the stiffening insert takes the form of a reinforcement loop extending continuously along a complete circumference of the tank body.

In one embodiment, the stiffening insert takes the form of a retaining strap provided with a fixing interface at each of its ends.

According to one embodiment, the stiffening insert and the tank body are made of the same thermoplastic material, in particular a high density polyethylene material.

In one embodiment, the fibers of the stiffening insert are unidirectional or multidirectional.

In one embodiment, the tank is chosen from one of the following tanks: fuel tank, depollution liquid tank, tank of fuel additives, windshield washer fluid tank, engine coolant tank.

The invention also relates to a method of manufacturing a tank characterized in that it comprises:

a step of manufacturing a stiffening insert made of a polymer material reinforced with fibers,

a step of placing the stiffening insert inside a mold,

- a step of extruding a parison inside the mold,

- a step of closing the mold,

- A step of blowing the parison so that at least one wall of the parison comes into contact with the mold and with the stiffening insert in order to ensure cohesion of material between the wall of the parison and the insert stiffening, and

- a step of opening the mold.

According to one implementation, the stiffening insert is produced by winding layers of a heated tape around a template so that the layers are superimposed on each other.

The invention will be better understood on reading the description which follows and on examining the figures which accompany it. These figures are given only by way of illustration but in no way limit the invention.

[Fig. 1] is a perspective view of a fluid reservoir comprising stiffening inserts according to the present invention;

[Fig. 2] is a perspective view of the stiffening inserts of a fluid reservoir according to the present invention;

[Fig. 3] is a schematic representation of a ribbon used for the production of the stiffening inserts according to the present invention;

[Fig. 4] is a schematic representation of a robot used to produce a stiffening insert by winding a heated tape around a template;

[Fig. 5a] to [Fig. 5d] are schematic representations of steps for producing a reservoir according to the invention by extrusion blow molding;

[Fig. 6] is an enlarged view of the interface between the tank body and the multilayer composite insert according to the present invention;

[Fig. 7a] to [Fig. 7b] are schematic representations illustrating alternative embodiments of the stiffening inserts for the fluid reservoir according to the present invention.

Similar or similar identical elements retain the same reference from one figure to another.

Figure 1 shows a fluid reservoir 10, in particular intended for use in a motor vehicle. The reservoir 10 may take the form of a fuel reservoir, a depollution liquid reservoir, a fuel additive reservoir, a windshield washer reservoir, a reservoir of engine cooling, or any other type of tank intended for use in a motor vehicle. The body 11 of the reservoir 10 defines a space for filling with a fluid.

The tank 10 further comprises at least one stiffening insert 12, 12 ', as shown in Figure 2, made of a polymeric material reinforced with continuous fibers. The insert 12, 12 'is overmolded on at least one wall of the tank body 11

10. The insert 12, 12 ′ may be overmolded on an internal face or on an external face of the reservoir 10. The continuous fibers may be chosen in particular from glass or carbon fibers. The stiffening insert 12, 12 ′ consists of several layers of a ribbon 17 (cf. FIG. 3) superimposed on each other, as is explained in more detail below.

The stiffening insert may take the form of a reinforcing loop 12. The insert 12 then extends continuously along a complete circumference of the body 11 of the tank 10. The insert 12 thus has an outline closed. Such a configuration makes it possible to considerably reinforce the reservoir 10. Advantageously, the reservoir 10 comprises at least one reinforcing loop 12. The number of reinforcing loops 12 is adapted as a function of the desired mechanical strength of the reservoir 10.

The stiffening insert may also take the form of a retaining strap 12 'provided with a fixing interface 14 at each of its ends in order to be able to fix the tank 10 in particular to the body of the vehicle. The strap 12 'extends over a portion of the circumference of the reservoir 10. The strap 12' is therefore open unlike the buckle 12. The attachment interface 14 may be an added interface molded onto a corresponding end of the strap 12 '. The fixing interface 14 is in this case made of a plastic material. As a variant, the fixing interface 14 is constituted by a hole for the passage of a fixing member, in particular an oblong hole, produced in a corresponding end of the strap 12 '. The end of the strap 12 ′ can be cut to obtain the hole, in particular by water jet or laser cutting, or any other cutting technology suited to the application. Likewise, the strap 12 ′ can be obtained by cutting an insert 12 in the form of a reinforcement loop according to one of the abovementioned technologies.

Advantageously, the insert 12, 12 'and the body 11 of the reservoir 10 are made of the same thermoplastic material, in particular a high density polyethylene material. Alternatively, these elements may be made of polyketone, polyamide, or any other polymeric material suitable for the application.

The following describes the method of manufacturing the reservoir 10 according to the invention provided with a stiffening insert 12, 12 'made of composite material.

This method comprises a step of producing a stiffening insert 12, 12 'made of a polymer material reinforced with fibers. For this purpose, as can be seen in FIG. 4, a robot 16 performs a winding of layers of a heated ribbon 17 around a template 18 so that the layers are superimposed on each other. All of these layers are compressed or hot-rolled to form the insert 12, 12 '. As can be seen in FIG. 5a, the insert 12, 12 ′ is placed inside a mold 25.

According to an exemplary embodiment, each layer of the ribbon 17 comprises a thermoplastic matrix 20 in which extend continuous fibers 21, as shown in FIG. 6. A width of the ribbon 17 and therefore of the insert 12, 12 'is between 2cm and 15cm, and is preferably between 2cm and 5cm. A thickness of the insert 12, 12 ′ may be between a few tenths of a millimeter and several millimeters, in particular between 1mm and 5mm, and preferably between 1mm and 2mm. The thickness could of course be adapted according to the forces that the insert 12, 12 'will have to bear.

An extruder 23 carries out an extrusion of a parison 24 inside the mold 25, as shown in FIG. 5a. The mold 25 is then closed as shown in Figure 5b. A step of blowing the parison 24 is carried out so that at least one wall of the parison 24 comes into contact with the mold 25 and with the insert 12, 12 ′ in order to ensure cohesion of material between the wall of the parison 24 and the insert 12, 12 ′, as shown in FIG. 5c. The mold 25 is opened at the end of the process and the part is removed from the mold after the part has cooled, as shown in FIG. 5d.

Figure 6 is an enlarged view of the interface I between the body 11 of the reservoir 10 and the insert 12, 12 'multilayer composite at the end of the manufacturing process. In this example, there is an insert 12, 12 ′ formed by six layers C1-C6 of ribbon 17 each comprising a matrix 20 of composite material and continuous fibers 21 seen in cross section. There is an absence of porosity or air bubbles at the interface I or between the layers C1-C6 of tape 17, so that there is no problem of decohesion of the assembly. A monobloc insert 12, 12 ′ is thus obtained which has a continuity of material with the body 11 of the reservoir 10. The mechanical connection between the reservoir 10 and the insert 12, 12 ′ is therefore robust and homogeneous.

The fibers 21 are preferably unidirectional and extend along the length of the ribbon 17. Alternatively, as shown in Figures 7a and 7b, the fibers 21 may be multidirectional, in particular extending in a vertical direction and in a horizontal direction. In the embodiment of FIG. 7a, the vertical and horizontal fibers 21 are superimposed on each other. In the embodiment of FIG. 7b, the fibers 21 of a given type (vertical or horizontal) pass alternately above and below the fibers 21 of the other type. Any other configuration of braiding the fibers 21 suitable for the application is of course conceivable.

Claims (11)

1- Fluid reservoir (10), in particular intended for use in a motor vehicle, comprising: a body (11) made of a polymer material, said body (11) delimiting a space for filling with a fluid, and, -a stiffening insert (12, 12 '), characterized in that the stiffening insert (12, 12') is made of a polymer material reinforced with fibers (21), said stiffening insert (12, 12 ' ) being overmolded on at least one wall of said tank body (11) (10). 2- fluid reservoir according to claim 1, characterized in that the fibers (21) are continuous. 3- fluid reservoir according to claim 1 or 2, characterized in that the stiffening insert (12,12 ') is constituted by several layers of a tape (17) superimposed on each other. 4- fluid reservoir according to any one of claims 1 to 3, characterized in that the stiffening insert takes the form of a reinforcement loop (12) extending continuously along a complete circumference of the body ( 11) of reservoir (10). 5- fluid reservoir according to any one of claims 1 to 3, characterized in that the stiffening insert takes the form of a retaining strap (12 ') provided with a fixing interface (14) to each of its ends. 6- Tank according to any one of claims 1 to 5, characterized in that the stiffening insert (12, 12 ') and the body (11) of the tank (10) are made of the same thermoplastic material, in particular a high density polyethylene material. 7- Tank according to any one of claims 1 to 6, characterized in that the fibers (21) of the stiffening insert (12, 12 ') are unidirectional or multidirectional. 8- Tank according to any one of claims 1 to 7, characterized in that the tank (10) is chosen from one of the following tanks: fuel tank, depollution liquid tank, tank of fuel additives, tank of windshield washer fluid, engine coolant tank. 9- Method for manufacturing a tank (10) characterized in that it comprises: a step of manufacturing a stiffening insert (12, 12 ′) made of a polymer material reinforced with fibers (21), a step of placing the stiffening insert (12, 12 ') inside a mold (25), a step of extruding a parison (24) inside said mold (25), a step of closing the mold (25), 5 - a step of blowing the parison (24) so that at least one wall of the parison (24) comes into contact with the mold (25) and with the stiffening insert (12, 12 ') in order to '' ensuring material cohesion between the wall of the parison (24) and the stiffening insert (12, 12 '), and a step of opening the mold (25). 10 10-A method according to claim 9, characterized in that the stiffening insert (12, 12 ') is produced by winding layers of a ribbon (17) heated around a template (18) so that the layers are superimposed on each other.