Front structure of a motor vehicle and motor vehicle comprising such a front structure

Abstract

The invention relates to a front structure of a motor vehicle comprising two lateral stretchers (10), two front supports (20) each comprising a main front wall (21) fixed to the front end of a said stretcher and at least one external side wall (22B), an upper bumper reinforcement comprising two lateral impact absorbers (42) extending in alignment with said stretchers and each comprising an anchoring plate (43) fixed by screwing via several longitudinal screws (V1) on the main front wall of a corresponding said front support, two hollow reinforcement boxes (50) each interposed longitudinally between the front facade of a said front support and the anchoring plate of a said absorber, being crossed by said longitudinal screws,and two wing liners (80) whose respective front ends are each fixed by screwing via several transverse screws (V2) to the external side wall of a said facade support as well as to a said box. Figure to be published with the abstract: Fig. 2,

Description

Title of the invention: Front structure of a motor vehicle and motor vehicle comprising such a front structure Technical field

[0001] The invention relates to the field of motor vehicles, more particularly to the deformation behavior of motor vehicles in the event of a low-overlap frontal impact, and relates to a front structure of a motor vehicle as well as a motor vehicle comprising such a front structure. Prior art

[0002] Among the plurality of tests used for the approval of motor vehicles, a small overlap frontal impact test (“Small Overlap Frontal Crash Test” in English terminology) is applied, in particular for the American market via the IIHS protocol (English acronym for “Insurance Institute for Highway Safety”) and for the Chinese market via the IASI protocol (English acronym for “Insurance Automobile Safety Index”).

[0003] This test consists of projecting a motor vehicle at a speed of 64 km / h towards a rigid obstacle such as a barrier, with an overlap range between the obstacle and the front of the vehicle of less than 25%. This type of test makes it possible to imitate impacts with a wall or a post at the front and side of the vehicle.

[0004] Generally speaking, the front structure of a motor vehicle comprises two structural elements, typically longitudinal structural beams, commonly called "stretchers" insofar as they may have a lateral profile similar to the arms of a stretcher intended to transport a person or objects. The structural beams extend longitudinally forward relative to the vehicle, on either side of the powertrain compartment of the vehicle, from a structural element of the passenger compartment.

[0005] Conventionally, the front ends of these stretchers are welded to front facade supports extending vertically relative to the vehicle and serving in particular to support the front facade crossmember of the vehicle intended to serve as a support for certain equipment of the vehicle's cooling system such as the radiator block and the motor-fan unit.

[0006] The front structure of a motor vehicle also includes an upper bumper reinforcement extending in front of these front supports and conventionally comprising a metal beam extending transversely as well as two side impact absorbers, commonly referred to by the Anglo-Saxon term "crash boxes", extending in alignment with the stretchers and each fixed by screwing via a plate on a corresponding facade support.

[0007] This first subassembly consisting of the upper bumper reinforcement and the two side members forms a first path for absorbing forces from the vehicle in the event of a frontal impact, generally called the “upper path” or “upper path”.

[0008] Below the side rails, the front structure of a vehicle may also include cradle extensions extending longitudinally on either side of the vehicle's powertrain compartment as well as a lower bumper reinforcement extending in front of these cradle extensions.

[0009] Having a conformation similar to the upper bumper reinforcement, such a lower bumper reinforcement conventionally comprises a beam extending transversely as well as two lateral absorbers extending in alignment with the cradle extensions and each fixed by screwing via a plate on the front end of a corresponding cradle extension.

[0010] This second subassembly consisting of the lower bumper reinforcement and the two cradle extensions forms a second path for absorbing forces from the vehicle in the event of a frontal impact, generally called the “lower path” or “lower path”.

[0011] In the event of a frontal impact of the vehicle, the transmission of transverse forces from one side of the vehicle to the other is then carried out by means of the lower and upper transverse beams of these sub-assemblies.

[0012] Wing liners extending longitudinally on either side of the engine compartment of the vehicle and the front end of which is screwed to an external side wall of a corresponding front support form a third force-recovery path allowing the transmission of forces from the front of the vehicle to other structural elements of the passenger compartment.

[0013] In the case of a high-speed frontal impact against a rigid obstacle with low overlap, one of these wing linings absorbs the majority of the forces and transmits them to the corresponding front support responsible for retransmitting them in particular to the upper transverse beam.

[0014] It has unfortunately been found that this facade support undergoes a strong deformation which does not allow it to correctly transmit the forces to this upper transverse beam.

[0015] Also, during a high-speed frontal impact against a rigid obstacle with low overlap, the front structure of the vehicle is subject to an input of combined transverse and longitudinal forces due to the vehicle moving forward against the obstacle, creating a torsional moment. The area of ​​the front support is also not very resistant to this torsional moment.

[0016] This poor resistance of the front support to transverse forces and to the torsional moment causes significant damage to the front structure of the vehicle during the course of the impact, as well as a significant risk of intrusion into the vehicle's passenger compartment.

[0017] In order to structurally reinforce the front support, particularly in the area of ​​transmission of transverse forces occurring during a frontal impact with low overlap, it is known from document FR 3 137 044 A1 to provide between each front support and the fixing plate of a corresponding lateral absorber of the upper bumper reinforcement, a hollow metal reinforcement body crossed by the screws for fixing this absorber to this front support. Statement of the invention

[0018] The present invention aims to improve the situation.

[0019] To this end, it proposes a front structure of a motor vehicle comprising: - two lateral stretchers extending longitudinally on either side of the engine compartment; - two facade supports each comprising a main front wall fixed to the front end of a corresponding side stretcher and at least one external side wall projecting in front of this main front wall from its external side edge; - an upper bumper reinforcement arranged in front of said facade supports and comprising a beam extending transversely as well as two lateral shock absorbers extending in alignment with said stretchers and each comprising an anchoring plate fixed by screwing via several longitudinal screws on the main front wall of a said corresponding facade support; - two hollow reinforcement boxes each interposed longitudinally between the front facade of a said facade support and the anchoring plate of a said corresponding absorber, being crossed by said longitudinal screws; and - two wing liners, the respective front ends of which are each fixed by screwing via several transverse screws to the external side wall of a said corresponding facade support; characterized in that the front end of each said wing lining is also fixed by said transverse screws to a corresponding said hollow reinforcing box.

[0020] The fact of also fixing each front end of a wing lining to the corresponding hollow reinforcement box makes it possible to ensure, when a frontal impact with low overlap occurs, better transmission of transverse forces between this wing lining, which first absorbs the impact, and the corresponding hollow reinforcement box.

[0021] According to preferred characteristics of said front structure according to the invention: - each said hollow reinforcement box comprises a front face plated against the anchoring plate of a said corresponding lateral absorber, a rear front facade pressed against the main front wall of a corresponding facade support, an upper panel extending between the upper edges of said facades, an internal lateral panel extending between the internal lateral edges of said facades, and an external lateral panel extending between the external lateral edges of said facades; - the external lateral panel of each said hollow reinforcement box is attached to the external lateral wall of a respective said facade support, at least at the level of the fixing zone by the said transverse screws of the said corresponding wing lining; - each said hollow reinforcement box houses several internal spacers extending longitudinally between said front facades and being crossed by said longitudinal screws; - the front facades of each said hollow reinforcement box each have, near their lower end, a respective fixing orifice, said fixing orifices of said facades being aligned longitudinally and crossed by a screw also passing through the main front wall of a respective facade support and being screwed onto a nut welded onto the rear face of this main front wall; - each said hollow reinforcement box is formed by the assembly of two half-shells each produced by stamping from a sheet of metal; - said front structure comprises a reinforcing crosspiece extending transversely between the two said hollow reinforcing boxes and the two ends of which are fixed by screwing via two anchoring lugs to the top portions of said boxes; - said reinforcing crosspiece is made up of two stamped sheet metal pieces fixed to each other by welding so as to form a hollow body; and / or - said reinforcing crosspiece comprises a hollow metal tube on the ends of which said two anchoring lugs are welded.

[0022] The invention also aims, in a second aspect, at a motor vehicle comprising such a front structure. Brief description of the drawings

[0023] The description of the invention will now be continued by the detailed description of an exemplary embodiment, given below for illustrative but non-limiting purposes, with reference to the appended drawings, in which: - [Fig.l] represents a three-quarter front perspective view of a front structure of a motor vehicle according to the invention; - [Fig.2] is an enlarged perspective sectional view taken from zone II of [Fig.l], taken along a horizontal sectional plane passing through the upper part of a facade support of this front structure; - [Fig.3] represents a perspective view of one of the two hollow support boxes comprising the front structure of the motor vehicle in [Fig.l]; - [Fig.4] is a perspective view of the reinforcing crossmember which comprises the front structure of the motor vehicle of [Fig.l] and extending fixedly between - [Fig.5] represents a partial perspective sectional view of this reinforcing crossmember taken along a vertical longitudinal sectional plane. Description of the embodiments

[0024] [Fig.l] represents a three-quarter front view of the left part of a front structure 1 of a motor vehicle according to the invention.

[0025] In the description which follows and by convention, we define with respect to this front structure 1 an orthogonal reference frame XYZ comprising three axes perpendicular two by two, namely: - an X axis, defining a longitudinal, horizontal direction, - a Y axis, defining a transverse, horizontal direction, which with the X axis defines a horizontal XY plane, and - a Z axis, defining a vertical direction, perpendicular to the horizontal XY plane.

[0026] In the remainder of the description and with reference to the reference defined above, the terms “longitudinal” or “longitudinally” will refer to a direction parallel to the X axis, the terms “transverse” or “transversely” will refer to a direction parallel to the Y axis, and the terms “vertical” or “vertically” will refer to a direction parallel to the Z axis.

[0027] On the other hand, the terms "front" and "rear" will be used to specify the longitudinal positioning of certain elements relative to the orientation of the X axis. Similarly, the terms "upper" and "lower" will be used to specify the relative position of certain elements relative to the orientation of the Z axis.

[0028] The terms "external" and "internal" will be used to define the relative position of an element with reference to the median vertical longitudinal plane of symmetry of this front structure 1. The element closest to this plane will thus be described as internal as opposed to the other element further away from this same plane which will be described as external.

[0029] Finally, the term "substantially" will indicate that a slight deviation is permitted from a predetermined nominal position or arrangement, while remaining included within the scope of the invention. For example, "substantially vertical" indicates that a deviation of the order of 15 to 20° from a strictly vertical orientation is permitted within the scope of the invention.

[0030] With reference to [Fig.l], the front structure 1 of a motor vehicle according to the invention comprises two parallel lateral stretchers made of sheet metal 10 (only that of left being shown in this [Fig. 1]) extending longitudinally forward, on either side of the engine compartment of the vehicle (the latter not being shown and mounted at location 2), from a structural element of the passenger compartment.

[0031] Two facade supports 20 each made from a stamped sheet of metal (only the one on the left being shown in this [Fig. 1]) are each fixed by welding to the front end of a corresponding lateral stretcher 10.

[0032] Each front support 20 is in the form of a hollow half-shell open at the front of rectangular parallelepiped shape and having an internal top protrusion on which is screwed a corresponding end of a front crosspiece 30 of the vehicle (generally made of plastic material) intended to serve as a support for certain equipment not shown of the vehicle's cooling system such as the radiator block and the motor-fan unit.

[0033] With reference to [Fig. 2], each facade support 20 thus conventionally comprises a main front wall 21 extending along a vertical transverse mean plane and fixed to the front end of a corresponding lateral stretcher 10, as well as a peripheral fallen edge projecting in front of this main front wall 21 and comprising in particular two internal 22A and external 22B lateral walls extending from the internal and external lateral edges of said main front wall 21.

[0034] The front structure 1 also comprises an upper bumper reinforcement 40 arranged in front of these front supports 20 and conventionally comprising a beam 41 extending transversely as well as two lateral shock absorbers 42 (only the one on the left being shown in this [Fig.l]) extending in alignment with the lateral stretchers 10.

[0035] These lateral absorbers 42 each comprise an anchoring plate 43 fixed by screwing via several longitudinal screws Vi onto the main front wall 21 of a corresponding facade support 20.

[0036] In order to structurally reinforce these facade supports 20 and in particular to improve their bending strength, the front structure 1 further comprises, in a known manner, two hollow reinforcement boxes 50 of substantially rectangular parallelepiped shape (only the one on the left being shown in this [Fig. 1]), extending along a vertical transverse mean plane and each housed in the volume defined by a respective facade support 20.

[0037] These hollow reinforcement boxes 50 are each interposed longitudinally between the main front wall 21 of a facade support 20 and the anchoring plate 43 of a corresponding lateral absorber 42, being crossed by the longitudinal screws Vp

[0038] As illustrated by [Fig. 3] showing an exploded view, each hollow reinforcement box 50 is formed by the assembly, via for example several weld beads, of two half-shells 50A, 50B produced by stamping from a sheet of sheet metal and each comprising a substantially rectangular main wall bordered along at least its upper and lateral sides by a fallen edge.

[0039] Each hollow reinforcement box 50 thus comprises: - a front frontal facade 51 pressed against the anchoring plate 43 of a corresponding lateral absorber 42 and formed by the half-shell 50A; - a rear front facade 52 pressed against the front main wall 21 of a corresponding facade support 20 and formed by the half-shell 50B; - an upper panel 53 extending between the upper edges of said facades 51, 52 and formed by the partially superimposed upper walls 53A, 53B of the fallen edges of these half-shells 50A, 50B; - an internal lateral panel 54 extending between the internal lateral edges of said facades 51, 52 and formed by the partially superimposed internal lateral walls 54A, 54B of the fallen edges of these half-shells 50A, 50B; and - an external lateral panel 55 extending between the external lateral edges of said facades 51, 52 and formed by the partially superimposed external lateral walls 55A, 55B of the fallen edges of these half-shells 50A, 50B.

[0040] The front 51 and rear 52 facades of each hollow reinforcement box 50 each have a plurality of respective passage orifices 511, 521, these orifices 511, 521 being aligned longitudinally two by two, so as to allow the longitudinal screws Vi to pass through the boxes 50.

[0041] In this case, each front facade 51, 52 has four orifices 511, 521 in relation to the number of screws Vi used for fixing each lateral absorber 42 to a facade support 20, but this number could of course be different.

[0042] Advantageously, each hollow reinforcement box 50 can house several internal spacers (not shown) extending longitudinally between its two front facades 51, 52 at the level of the periphery of its orifices 511, 521 and being crossed by the longitudinal screws Vp

[0043] In order to reduce the mass of these hollow reinforcement boxes 50, their front 51 and rear 52 frontal facades can advantageously have lightening cutouts 512, 522 covered respectively by the anchoring plates 43 of the upper bumper reinforcement 40 and by the main frontal walls 21 of the facade supports 20.

[0044] In order to improve the holding of each hollow reinforcement box 50, these front 51 and rear 52 frontal facades can each advantageously have, near their lower end, a respective fixing orifice 513, 523, these orifices 513, 523 being aligned longitudinally and crossed by a screw not shown also passing through the main frontal wall 21 of a respective facade support 20 and being screwed onto a nut welded onto the rear face of this main frontal wall 21.

[0045] The front 51 and rear 52 facades may also each have a passage hole 514, 524 provided in this case in their lower part, these passage holes being aligned longitudinally and provided to be crossed by a towing hook not shown, also crossing the main front wall 21 of a respective facade support 20 and coming to be screwed onto a nut welded on the rear face of this main front wall 21.

[0046] Below the side stretchers 10, the front structure 1 further comprises two cradle extensions 60 (only the left one being shown in this [Fig.l]) extending longitudinally on either side of the powertrain compartment of the vehicle, as well as a lower bumper reinforcement 70 extending in front of these cradle extensions 60.

[0047] Having a similar conformation to the upper bumper reinforcement 40, the lower bumper reinforcement 70 comprises a beam 71 extending transversely as well as two lateral absorbers 72 extending in alignment with the cradle extensions 60 and each fixed by screwing via an anchoring plate 73 on the front end of the corresponding cradle extension 60.

[0048] The front structure 1 also comprises two wing linings 80 (only the left one being shown in this [Fig.l]) extending longitudinally on either side of the engine compartment of the vehicle and the respective front ends of which are each fixed by screwing, via several transverse screws V2, to the external lateral wall 22B of a facade support 20 thus corresponding, and according to the invention, to the external lateral panel 55 of a corresponding hollow reinforcement box 50 (see [Fig.2]).

[0049] In this case and with reference to [Fig. 2], each screw V2 thus passes successively and in a transverse direction through the front end of a wing lining 80, the external side wall 22B of a facade support 20, and the external side panel 55 of a hollow reinforcement box 50 (attached to this external side wall 22B at least at the level of the fixing zone by said screws V2 of this wing lining 80), in this case being screwed onto a nut E2 welded to the internal periphery of the upper portion of the external side wall 55B of the half-shell 50B and inserted transversely between this upper portion of the external side wall 55B and the upper portion of the external side wall 55A of the half-shell 50A.

[0050] The fact of also fixing each front end of a wing lining 80 to the corresponding hollow reinforcement box 50 makes it possible to ensure, when a frontal impact with low overlap occurs, better transmission of the transverse forces between this wing lining 80, which first absorbs the impact, and the corresponding hollow reinforcement box 50.

[0051] This improvement in the absorption of transverse forces by this hollow reinforcement box 50 thus makes it possible to optimize the mechanical strength of the facade support 20 and to limit significantly its structural deformation during such an impact.

[0052] In order to allow a part of the forces to be taken up by the lateral part opposite the impact of the front structure 1 of the vehicle, the latter may advantageously comprise a reinforcing crossmember 90 extending transversely between the two hollow reinforcing boxes 50, in front of the front facade crossmember 30, and the two ends of which are fixed by screwing to the top portions of these boxes 50.

[0053] Reserved for example for certain high-end vehicle models, the addition of such a reinforcing crossmember 90 could thus make it possible to obtain a better rating in the low overlap frontal impact test (typically moving from an acceptable safety level to a satisfactory safety level or “Good” according to Anglo-Saxon terminology).

[0054] To ensure its attachment to the two hollow reinforcement boxes 50 and with reference to [Fig.4], each end of this reinforcement crosspiece 90 comprises an anchoring lug 91 in the form of a bracket, comprising a front wall 911 and an upper wall 912 projecting at the rear of this front wall from the external portion of the upper edge of this front wall 911.

[0055] The front wall 911 of each anchoring lug 91 has at least one oblong orifice 913 oriented transversely (in this case, two spaced transversely from each other) and crossed by a respective screw V3 also crossing a corresponding orifice 515 formed in the upper part of the front front facade 51 of a corresponding hollow reinforcement box 50 (see [Fig.3]) and screwed onto a nut E3 welded onto the rear face of this front front facade 51 (see [Fig.2]).

[0056] In the same way, the upper wall 912 of each anchoring lug 91 has at least one oblong orifice 914 oriented transversely (in this case, a single orifice) and crossed by a respective screw V4 also passing through a corresponding orifice formed in the upper face 53 of a corresponding hollow reinforcement box 50 (this orifice being formed by two superimposed orifices 516A, 516B formed in the partially superimposed upper walls 53A, 53B of these half-shells 50A, 50B as illustrated by [Fig. 3]) and being screwed onto a nut not visible in the figures welded onto the lower face of the upper wall 53A of the half-shells 50A.

[0057] It will be noted that the fact of providing such oblong orifices 913, 914 on the anchoring lugs 91 makes it possible to absorb the dimensional dispersions of transverse spacing between the two hollow reinforcement boxes 50 due to the normal manufacturing tolerances of the various constituent parts of this front structure 1.

[0058] As illustrated by [Fig. 5], the reinforcing crosspiece 90 is advantageously hollow, being made up for example of two stamped sheet metal parts 90A, 90B, having respectively in section a right-angled profile and a W-shaped profile, and fixed to each other. by several electric welding points (EPS) so as to form a hollow body.

[0059] According to alternative embodiments not shown, this reinforcing crosspiece may be shaped differently; it may for example comprise a hollow metal tube on the ends of which two anchoring lugs such as the lugs 91 are welded so as to allow its attachment to the hollow reinforcing boxes 50.

[0060] Numerous variants are conceivable and it is recalled in this regard that the present invention is not limited to the embodiments described and shown, but also encompasses all the variants of execution within the reach of those skilled in the art.

Claims

Claims

1. Front structure (1) of a motor vehicle comprising: - two side stretchers (10) extending longitudinally on either side of the engine compartment; - two front supports (20) each comprising a main front wall (21) fixed to the front end of a corresponding side stretcher (10) and at least one external side wall (22B) projecting in front of this main front wall (21) from its external lateral edge; - an upper bumper reinforcement (40) arranged in front of said front supports (20) and comprising a beam (41) extending transversely as well as two lateral shock absorbers (42) extending in alignment with said stretchers (10) and each comprising an anchoring plate (43) fixed by screwing via several longitudinal screws (Vi) on the main front wall (21) of a said corresponding front support (20);- two hollow reinforcement boxes (50) each interposed longitudinally between the front facade (21) of a said facade support (20) and the anchoring plate (43) of a said corresponding absorber (42) being crossed by said longitudinal screws (VJ; and - two wing linings (80) whose respective front ends are each fixed by screwing via several transverse screws (V2) to the external side wall (22B) of a said corresponding facade support (20); characterized in that the front end of each said wing lining (80) is also fixed by said transverse screws (V2) to a said corresponding hollow reinforcement box (50).;

2. Front structure (1) according to claim 1, characterized in that each said hollow reinforcement box (50) comprises a front frontal facade (51) pressed against the anchoring plate (43) of a said corresponding lateral absorber (42), a rear frontal facade (52) pressed against the main frontal wall (21) of a corresponding facade support (20), an upper panel (53) extending between the upper edges of said facades (51, 52), an internal lateral panel (54) extending between the internal lateral edges of said facades (51, 52), and an external lateral panel (55) extending between the external lateral edges of said facades (51, 52).

3. Front structure (1) according to claim 2, characterized in that the external side panel (55) of each said hollow reinforcement box (50) is attached to the external side wall (22B) of a respective said facade support (20), at least at the level of the fixing zone by said transverse screws (V2) of said corresponding wing lining (80).

4. Front structure (1) according to one of claims 2 or 3, characterized in that each said hollow reinforcement box (50) houses several internal spacers extending longitudinally between said front facades (51, 52) and being crossed by said longitudinal screws (VJ.

5. Front structure (1) according to one of claims 2 to 4, characterized in that the front facades (51, 52) of each said hollow reinforcement box (50) each have, near their lower end, a respective fixing orifice (513, 523), said fixing orifices (513, 523) of said facades (51, 52) being aligned longitudinally and crossed by a screw also passing through the main front wall (21) of a respective facade support (20) and being screwed onto a nut welded onto the rear face of this main front wall (21).

6. Front structure (1) according to one of claims 1 to 5, characterized in that each said hollow reinforcement box (50) is formed by the assembly of two half-shells (50A, 50B) each produced by stamping from a sheet of metal.

7. Front structure (1) according to one of claims 1 to 6, characterized in that it comprises a reinforcing crosspiece (90) extending transversely between the two said hollow reinforcing boxes (50) and the two ends of which are fixed by screwing via two anchoring lugs (91) to the top portions of said boxes (50).

8. Front structure (1) according to claim 7, characterized in that said reinforcing crosspiece (90) consists of two stamped sheet metal parts (90A, 90B) fixed to each other by welding so as to form a hollow body.

9. Front structure (1) according to claim 7, characterized in that said reinforcing crosspiece (90) comprises a hollow metal tube on the ends of which said two anchoring lugs are welded.

10. Motor vehicle comprising a front structure (1) according to one of claims 1 to 9.

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