VEHICLE WING WITH FUSABLE AREA FOR PROGRAMMED DEFORMATION

Description

[0001] The invention relates to the field of managing front impacts involving motor vehicles and the passive safety means that can be implemented in managing such impacts. In particular, the invention relates to motor vehicles suitable for managing low-speed frontal impacts, of the "repairable impact" type. The invention also relates to the wings of such vehicles.

[0002] Current regulations require motor vehicle manufacturers to comply with certain safety constraints and to carry out tests in order to obtain the approval necessary for any marketing. Thus, the front of a vehicle must simultaneously satisfy several frontal impact protocols, including the high-speed offset frontal impact protocol and the low-speed frontal impact (or "frontal impact repairability"). The various requirements are often met through so-called "passive safety" methods that require no action on the part of the vehicle user.

[0003] In the "front impact repairability" protocol, a vehicle is launched at 16 km / h over 40% of its width against a buffer. This tests the deformation process of the front of the vehicle. The objective is to promote deformation processes that minimize damage by absorbing all of the impact energy. This prevents other vehicle components (such as the strut heads and cooling equipment) from being damaged by the impact. This makes it possible to limit vehicle repair costs and keep the vehicle drivable after the impact.

[0004] In such an impact, the front headlight (or headlight optic) on the impact side is affected. The front headlight will usually be displaced towards the rear of the vehicle and rotate when the barrier shows an impact angle of, for example, 10°. The front wing of the vehicle, running alongside the wheel and housing the shock absorber, is also likely to be affected, in particular due to the rearward movement of the headlight. Indeed, in certain vehicle architectures, the support of the headlight on the front wing causes it to move backward, generating contact with the front side door. The mobility of the front side door, which is pivotally hinged at the rear limit of the wing, may be compromised when the front wing is deformed. In other words, the opening of the door may be hindered or prevented by contact with the deformed sheet metal of the wing.

[0005] It is understood that this contact risks damaging the side door before it is during the impact itself or after the impact, the next time it is opened. Indeed, the contact between the rear edge of the wing and the front edge of the door generates, in the best case, a scratch requiring a paint touch-up. In other more serious cases, the door is damaged, deformed, when it is opened and it must be replaced.

[0006] Damage to the door generates additional costs in terms of vehicle repairs and a poor classification of the vehicle in terms of repairability in the rate schedules of some insurance companies. A solution therefore remains to be found to overcome this problem.

[0007] Document JP H11 222154 discloses a fender for a motor vehicle according to the preamble of claim 1.

[0008] Document FR3058689 proposes a set of elements intended to prevent rotation of material from the wing towards the front side door in the event of a low-speed front impact. In the proposed solution, a support is arranged between the wing, the headlight and the vehicle structure. Furthermore, a frangible spacer is arranged between the wing and the headlight. The support is arranged in sliding connection with the headlight body and fixed to the wing. In the event of an impact at the front of the vehicle, a reciprocal approach of the headlight body and the wing by sliding along the slide and retraction of the frangible spacer is favored to the detriment of said rotation of material from the wing. This set of elements makes it possible to preserve the maneuverability of the door after the impact.

[0009] This solution is interesting. However, it was found that the wing could still be subjected to heavy stress and deform, generating recoil and thus contact between the wing and the front door.

[0010] The invention aims to provide a solution to at least one of the problems or drawbacks encountered in the prior art. In particular, the invention aims to propose a solution for improving the management of low-speed frontal impacts so as to avoid, or at least limit, the risk of damage to the front side doors.

[0011] For this purpose and according to a first aspect, the invention relates to a wing for a motor vehicle according to claim 1, said wing showing an upper edge and a wheel arch delimited by a dropped edge, the wing is remarkable in that it comprises at least one fusible zone arranged at the level of the wheel arch and / or at the level of the upper edge in its portion arranged vertically to the wheel arch.

[0012] According to another definition, the invention relates to a wing for a motor vehicle, said wing showing an upper edge and a wheel arch delimited by a dropped edge, the wing is remarkable in that it comprises at least one fusible zone showing reduced mechanical resistance compared to the rest of the wing, at least one fusible zone being arranged at the level of the wheel arch and / or at the level of the upper edge in its portion arranged vertically to the wheel arch.

[0013] As will be understood from reading the definition just given, the invention consists in promoting a deformation of the vehicle wing at the wheel arch by providing a fusible zone to said arch and / or the upper edge of the wing arranged vertically to said arch. A fusible zone is an area showing reduced mechanical resistance compared to the rest of the wing. Thus, under the application of a force greater than a predetermined threshold, the wing will bend at the fusible zone instead of moving back towards the door. Contact between the wing and the door is therefore avoided, or at least, the risk of contact is reduced.

[0014] According to a first preferred embodiment of the invention, there or at least one fusible zone is arranged on the fallen edge of the wheel arch. Preferably, there or at least one fusible zone comprises at least one notch made in the fallen edge. More preferably, said notch has a U or V shape.

[0015] The upper edge also showing a fallen edge, where at least one fusible zone is arranged on the fallen edge of the upper edge of the wing. Preferably, where at least one fusible zone comprises at least one notch made in the fallen edge. More preferably, said notch shows a U or V shape.

[0016] The flanged edge has, among other things, a role of stiffening the edge of the wing forming the wheel arch or the upper edge of the wing depending on its location. By making a notch on said flanged edge, the invention promotes the initiation of a folding of the wing at the level of said notch. This folding allows the wing to move back less compared to the previous situation, or even to no longer move back, and therefore limits the risks of damage to the door. The notch is made during the production of the wing, and more particularly by cutting during the stamping operations.

[0017] Advantageously, where at least one fusible zone comprises at least one notch made in the fallen edge of the wheel arch, the wing is remarkable in that it comprises a single notch forming a fusible zone on the fallen edge of the wheel arch. Indeed, it has been found by the inventors that wings showing a single notch on the fallen edge of their wheel arch, showed better performance in terms of door protection than wings showing two or more notches distributed on the fallen edge forming the wheel arch.

[0018] Ideally, where at least one fusible zone comprises at least one notch made in the fallen edge of the wheel arch, the fender is remarkable in that where at least one notch is arranged at the high point of said wheel arch. It has been found by the inventors that the arrangement of the notch at the high point of said wheel arch is the arrangement in which the presence of a notch on the fallen edge gives the best results in terms of protection of the door, compared to a fender showing a notch on said fallen edge arranged in front of or behind said high point.

[0019] According to a second alternative or complementary embodiment to the first embodiment, the wing being formed by a sheet metal, the wing is remarkable in that there or at least one fusible zone is formed by a strip of sheet metal showing a reduced thickness compared to the thickness of the rest of the sheet metal forming the wing. Due to its reduced thickness, the strip of sheet metal shows a reduced mechanical resistance compared to the mechanical resistance shown by the rest of the sheet metal forming the wing.

[0020] According to a third alternative or complementary embodiment to the first and / or second embodiment, the wing being formed by a sheet metal, the wing is remarkable in that there or at least one fusible zone is formed by a strip of sheet metal heat-treated so as to show reduced mechanical resistance compared to the mechanical resistance shown by the rest of the sheet metal forming the wing.

[0021] Whether the sheet metal strip forming a fusible zone shows a reduced thickness and / or has been heat-treated, the wing showing an upper edge, the wing is remarkable in that the sheet metal strip forming a fusible zone is arranged on the flanged edge of the wheel arch; and / or extends between the upper edge of the wing and the flanged edge of the wheel arch in a vertical direction or in a direction showing an angle with the vertical equal to or less than 45°.

[0022] Ideally, the fender showing an upper edge, the fender is notable in that the sheet metal strip forming a fusible zone extends between the upper edge of the fender and the fallen edge of the wheel arch and in that said strip extends from the high point of the wheel arch and / or in that the sheet metal strip forming a fusible zone further shows a notch at the fallen edge of the wheel arch.

[0023] According to a second aspect, the invention relates to a motor vehicle which is remarkable in that it comprises at least one wing according to the first aspect; preferably, said wing is a front wing.

[0024] According to a third aspect, the invention relates to a method of manufacturing a wing according to the first aspect from a sheet metal.

[0025] In the first variant embodiment of the invention according to which the wing shows at least one notch arranged on its fallen edge, the method is remarkable in that it comprises a step of cutting at least one notch in the wheel arch followed by the production of a fallen edge on the wheel arch, said notch or notches being sized to be confined to said fallen edge.

[0026] In the second embodiment of the invention according to which the wing shows at least one strip of sheet metal of reduced thickness, the method is remarkable in that it comprises a step of flexible rolling of said sheet metal so as to form at least one strip showing a reduced thickness; preferably, said flexible rolling step is followed by a step of stamping and cutting the sheet metal so as to form said wing.

[0027] In the third embodiment of the invention according to which the wing shows at least one strip of sheet metal heat-treated so as to show reduced mechanical resistance, said sheet being made of steel, the method is remarkable in that it comprises a localized heat treatment step capable of creating a soft zone showing reduced mechanical resistance in which the strip of sheet metal is heated to a temperature between Ac1 and Ac3 of the steel sheet; preferably, said heat treatment step is followed by a step of stamping and cutting the sheet metal so as to form said wing.

[0028] The invention will be well understood and other aspects and advantages will appear clearly on reading the following description given with reference to the attached drawings in which: [ Fig.1 ] There figure 1 is a partial view of a motor vehicle wing as seen from its internal face with inset the detail of an example of the production of a fusible zone on the fallen edge of the wheel arch. Fig.2 ] There figure 2 is a graph showing the results of wing recoil tests with and without a fusible zone in a low-speed frontal impact.

[0029] In the following description, the term "comprise" is synonymous with "include" and is not limiting in that it allows the presence of other elements in the vehicle or in the wing to which it relates. It is understood that the term "comprise" includes the terms "consist of". "Lower" or "low" will denote a greater proximity to the ground than "upper" or "high" along the vertical axis. The terms "front" and "rear" will be understood in relation to the general orientation of the vehicle. In the different figures, the same references denote identical or similar elements.

[0030] We will first refer to the figure 1 partially showing a wing 1 of a motor vehicle as seen from its internal face, that is to say facing towards the inside of the vehicle, as opposed to the external face. According to the invention, the wing has at least one fusible zone 7 at the level of the wheel arch 3 and / or at the level of the upper edge 9 in its portion arranged vertically of the wheel arch 3.

[0031] The wing 1 may have one or more fusible zones 7; preferably, the wing 1 has a single fusible zone 7.

[0032] This fusible zone 7 can take different forms. According to a first embodiment illustrated in figure 1 , the fusible zone 7 is arranged on the fallen edge 5 of the wheel arch 3 and comprises at least one notch made in said fallen edge 5. The characteristics of the fusible zone 7 arranged on the fallen edge 5 of the wheel arch 3 are applicable to a fusible zone arranged on the fallen edge of the upper edge 9 of the wing.

[0033] Indeed, in a known manner, the wing 1 comprises a wheel arch 3 bordered by a flanged edge 5. It is recalled, if necessary, that a flanged edge 5 corresponds to the edge of a sheet metal part which is returned at 90° in a given stamping direction. In the present case, the flanged edge 5 extends on the side of the internal face of the wing 1. The flanged edge 5 conventionally has two functions: on the one hand, it makes it possible to reduce the severity of injuries in the event of physical impact of a pedestrian on the edge of the wheel arch; on the other hand, its function is to reinforce the edge of the panel forming the wing 1. As such, it contributes to the transmission of the forces received by the wing and to its rigidity.

[0034] The invention is therefore remarkable in that it proposes a motor vehicle fender 1 in which the flanged edge 5 shows a fusible zone 7 so as to initiate a folding of said fender 1 by proposing a zone of reduced mechanical resistance at the level of a reinforcement relief of said fender 1. The fusible zone 7 comprises at least one notch; preferably a single notch. Said notch is advantageously produced by a cutting operation during the manufacturing process of the fender 1 by stamping before the production of the flanged edge 5 itself. To this end, it advantageously has a V or U shape; preferably a V shape. At least one notch extends over at least 50% of the width of the flanged edge 5, preferably over at least 80% of the width of the flanged edge 5; more preferably over the entire width of the flanged edge 5.

[0035] It is possible to make several notches distributed along the length of the flanged edge 5 of the wheel arch 3, for example two or three notches. However, the tests carried out have shown that the configuration with a single notch was the most effective. Similarly, if it is possible to cut the notch or notches in different locations of the wheel arch, it is preferable to cut a notch at the high point of said wheel arch, that is to say at the point where a tangent to the arc of a circle formed by the wheel arch is horizontal. However, other locations may be envisaged by those skilled in the art, in front of or behind said high point. For example, the notch or notches may be arranged on an arc of a circle shown on the wheel arch subtending an angle centered on the vertical and showing a total value of 60°, that is to say 30° on either side of the vertical; preferably a total value of 45°.

[0036] According to a second alternative or complementary embodiment to the first embodiment, where at least one fusible zone is formed by a strip of sheet metal showing a reduced thickness compared to the thickness of the rest of the sheet metal forming the wing. The production of sheets showing different thicknesses is known to those skilled in the art and can be carried out by a flexible rolling process. The use of sheets showing a variable thickness as well as the methods for manufacturing such a sheet metal by flexible rolling are known to those skilled in the art. Document KR101825427 describes a method for flexible rolling of the bodywork of a vehicle opening. Another example is given by document EP2044234. Those skilled in the art will carry out the flexible rolling step before the steps of stamping and cutting the wing.

[0037] When the reduced thickness sheet metal strip is confined to the flanged edge, the thickness reduction can be achieved by machining.

[0038] According to a third alternative or complementary embodiment to the first and / or second embodiment, there or at least one fusible zone is formed by a strip of sheet metal heat-treated so as to show reduced mechanical strength compared to the mechanical strength shown by the rest of the sheet metal forming the wing. In a known manner, a localized heat treatment can allow the creation of soft zones (called "soft zones" in English) by a local modification of the microstructure of the steel from a martensitic type structure to a microstructure composed of ferrite or pearlite. The local modification of the microstructure of the steel causes a local reduction in its mechanical strength. Document US2017044637 describes such a heat treatment in the context of the assembly by riveting of two sheets.The method implemented comprises a heat treatment step with heating of the area intended to show reduced mechanical strength of the steel to a temperature below the Ac3 temperature of the steel sheet and above the Ac1 temperature or up to the Ac1 temperature minus 20°C of said steel sheet. The implementation of such a heat treatment makes it possible, for example, to go from a tensile strength of at least 1200 MPa to less than 750 MPa, without affecting the tensile strength of the rest of the sheet, outside the soft zones. The strip of sheet showing a soft zone can be confined to the flanged edge.

[0039] The production of at least one fusible zone at the level of the fallen edge of the wheel arch corresponds to a preferred implementation of the invention, however other locations can be envisaged. Thus, the person skilled in the art will be able to provide fusible zones arranged on the fallen edge of the upper edge of the wing as taken vertically from the wheel arch, or extending beyond the fallen edge of the wheel arch or the upper edge of the wing.

[0040] Whether the sheet metal strip forming a fusible zone has a reduced thickness and / or has been heat-treated, the wing showing an upper edge 9, the person skilled in the art will benefit from the sheet metal strip forming a fusible zone extending between the upper edge 9 of the wing 1 and the edge forming the wheel arch 3 and in a vertical direction or in a direction showing an angle with the vertical equal to or less than 45°. Preferably, the sheet metal strip forming the fusible zone is arranged vertically and joins the upper edge 9 of the wing 1 with the high point of the wheel arch 3.

[0041] It is possible to combine the embodiments of the fusible zones. For example, it is possible to make a notch on the fallen edge of the wheel arch at the point where a strip of sheet metal showing reduced mechanical resistance joins said wheel arch.

[0042] There figure 2illustrates the results of comparative tests carried out within the framework of the invention. The graph shows the maximum dynamic recoil as measured at the midpoint of the rear edge of a wing during a low-speed impact. Curve A represents the recoil of a wing showing a fusible zone 7 formed by a notch arranged on the fallen edge of the wheel arch of said wing at its high point. Curve B represents the recoil of a wing according to the prior art, that is to say without a fusible zone. It can be seen that the recoil is significantly lower in the case of the wing according to the invention.

Claims

1. Motor vehicle wing (1), said wing (1) showing an upper edge (9) and a wheel arch (3) delimited by a flanged edge (5), the wing (1) comprises at least one fusible zone (7) showing reduced mechanical strength by report with the remainder of the wing (1), at least one fusible zone (7) being arranged on the level of the wheel arch (3) and / or on the level of the upper edge (9) in its portion arranged vertically above the wheel arch (3), the wing (1) being formed by a On the sheet metal, the flange (1) is characterised in that where at least one fusible zone (7) is formed by a sheet metal strip showing a reduced thickness by report with the thickness of the remainder of the sheet metal forming the flange (1) and / or by a sheet metal strip heat-treated so as to show a reduced mechanical strength by report with the mechanical strength shown by the remainder of the sheet metal forming the flange (1).

2. Wing (1) according to Claim 1, characterised in that there or at least one fusible zone (7) is arranged on the flanged edge (5) of the wheel arch (3); preferably, there or at least one fusible zone comprises at least one realised notch in the flanged edge (5) of the wheel arch (3).

3. Wing (1) according to Claim 2, where at least one fusible zone comprises at least one realised notch in the flanged edge of the wheel arch; the wing (1) is characterised in that it comprises a single notch forming a fusible zone (7) on its flanged edge (5) and / or in that where at least one notch is arranged at the high point of said wheel arch (3).

4. Wing (1) according to any one of the previous claims, the wing (1) showing an upper edge (9), the wing (1) being characterised in that the strip of sheet metal forming a fusible zone extends between the upper edge (9) of the wing (1) and the flanged edge (5) of the wheel arch (3) according to a vertical management or according to a management showing an angle with the vertical equal to or less than 45°.

5. Wing (1) according to any one of the previous claims, the wing (1) showing an upper edge (9), the wing (1) being characterised in that the sheet metal strip forming a fusible zone extends between the upper edge (9) of the wing (1) and the flanged edge (5) of the wheel arch (3) and in that the said strip extends from the top point of the wheel arch (3) and / or in that the sheet metal strip forming a fusible zone also shows a notch on the level of the flanged edge (5) of the wheel arch (3).

6. Motor vehicle, characterised in that it comprises at least one wing (1) according to one of Claims 1 to 5; preferably, the said wing (1) is a front wing.

7. Process for manufacturing a wing (1) according to one of Claims 1 to 3 or 5, characterised in that it comprises a step of cutting at least one notch in the wheel arch (3) followed by the production of a flanged edge (5) on the wheel arch (3), the said notch or notches being dimensioned to be confined to the said flanged edge (5).

8. Process for manufacturing a wing (1) according to one of Claims 1 to 5, from a sheet, the wing (1) showing at least one strip of sheet of reduced thickness, the process being characterised in that it comprises a step of flexible rolling of the said sheet so as to form at least one strip showing a sub-thickness; preferably, the said step of flexible rolling is followed by a step of stamping and cutting of the sheet so as to form the said wing (1).

9. Process for manufacturing a wing (1) according to one of Claims 1 to 5, from a sheet, the wing (1) showing at least one strip of sheet metal heat-treated so as to show reduced mechanical strength, the said sheet metal being made of steel, the process being characterised in that it comprises a localised heat treatment step capable of producing a soft zone showing reduced mechanical strength in which the strip of sheet metal is heated to a temperature comprised between the Ac1 and Ac3 of the sheet metal; preferably, the said heat treatment step is followed by a stamping and heating step cutting the sheep so as to form said flange (1).