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

Abstract

The invention relates to a front structure of a motor vehicle comprising two lateral crossbars (10), two front supports (20) each comprising a main front wall (21) fixed to the front end of said crossbar and at least one external side wall (22B), an upper bumper reinforcement comprising two lateral shock absorbers (42) extending in line with said crossbars and each comprising an anchoring plate (43) fixed by screwing via several longitudinal screws (V1) onto the main front wall of a corresponding front support, two hollow reinforcing boxes (50) each interposed longitudinally between the front face of said front support and the anchoring plate of said absorber, through which said longitudinal screws pass.and two wing linings (80) whose respective front ends are each fixed by screwing via several transverse screws (V2) to the external side wall of said facade support and to said box. Figure to be published with the abbreviation: 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 concerns a front structure of a motor vehicle as well as a motor vehicle comprising such a front structure. Previous technique

[0002] Among the plurality of tests used for the homologation of motor vehicles, a small overlap frontal crash test is applied, in particular for the American market via the IIHS protocol (Anglo-Saxon acronym for "Insurance Institute for Highway Safety") and for the Chinese market via the IASI protocol (Anglo-Saxon acronym for "Insurance Automobile Safety Index").

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

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

[0005] Conventionally, the front ends of these stretchers are welded onto front front supports extending vertically relative to the vehicle and serving in particular to support the front front 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 assembly.

[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 lateral shock absorbers, commonly referred to by the Anglo-Saxon term "crash boxes", extending in line with the frame members and each fixed by screws via a mounting plate on a corresponding facade support.

[0007] This first sub-assembly consisting of the upper bumper reinforcement and the two stretchers forms a first path for the transfer of 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 and a lower bumper reinforcement extending in front of these cradle extensions.

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

[0010] This second sub-assembly consisting of the lower bumper reinforcement and the two cradle extensions forms a second way of absorbing vehicle forces in the event of a frontal impact, generally called the "lower track" or "lower track".

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

[0012] Wing linings extending longitudinally on either side of the vehicle's powertrain compartment and whose front end is fixed by screwing to an external side wall of a corresponding front support form a third way of force transfer 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 most of the forces and transmits them to the corresponding front support responsible for transmitting them in particular to the upper transverse beam.

[0014] It has unfortunately been observed that this facade support undergoes a strong deformation which prevents it from properly transmitting the forces to this upper transverse beam.

[0015] Also, during a high-speed frontal impact against a rigid obstacle with minimal overlap, the front structure of the vehicle is subjected to combined transverse and longitudinal forces due to the vehicle's forward movement against the obstacle, creating a torsional moment. The front support area is also relatively resistant to this torsional moment.

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

[0017] In order to structurally reinforce the facade support, particularly in the area of ​​transmission of transverse forces occurring during a low overlap frontal impact, it is known from document FR 3 137 044 Al to provide between each facade support and the fixing plate of a corresponding lateral absorber of the upper bumper reinforcement, a hollow metal reinforcing body through which the fixing screws of this absorber to this facade support are passed. Description of the invention

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

[0019] For this purpose, it proposes a front structure for a motor vehicle comprising: - two lateral beams 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 lateral stretcher and at least one external lateral wall projecting in front of this main front wall from its external lateral 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 line with said stretchers and each comprising an anchoring plate fixed by screwing via several longitudinal screws on the main front wall of a corresponding said facade support; - two hollow reinforcing boxes, each interposed longitudinally between the front face of said facade support and the anchoring plate of said corresponding absorber, through which said longitudinal screws pass; and - two wing linings, the respective front ends of which are each fixed by screwing via several transverse screws to the external side wall of 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 hollow reinforcing box.

[0020] Fixing each front end of a wing lining to the corresponding hollow reinforcement box also ensures, in the event of a low overlap frontal impact, 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 reinforcing box comprises a front plated facade against the anchoring plate of a corresponding lateral absorber, a rear front face 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 side panel of each said hollow reinforcement box is attached to the external side wall of a said respective facade support, at least at the level of the area of ​​attachment by the said transverse screws of the said corresponding wing lining; - each said hollow reinforcing box houses several internal spacers extending longitudinally between said front facades and being crossed by said longitudinal screws; - the front faces of each of said hollow reinforcing box each have, near their lower end, a respective fixing hole, said fixing holes of said faces being aligned longitudinally and crossed by a screw also passing through the main front wall of a respective face support and screwing into a nut welded on the rear face of this main front wall; - each said hollow reinforcing box is formed by the assembly of two half-shells, each made by stamping from a sheet of metal; - said front structure includes a reinforcing cross member extending transversely between the two said hollow reinforcing boxes and whose two ends are fixed by screwing via two anchoring tabs to the summit portions of said boxes; - said reinforcing cross member consists of two pieces of stamped sheet metal welded together to form a hollow body; and / or - said reinforcing cross member comprises a hollow metal tube onto the ends of which said two anchoring lugs are welded.

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

[0023] The description of the invention will now be continued by a detailed description of an exemplary embodiment, given below by way of illustration but not limitation, with reference to the accompanying drawings, on 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 cross-sectional view taken from zone II of [Fig.1], taken along a horizontal cross-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 that comprise the front structure of the motor vehicle in [Fig.1]; - [Fig.4] is a perspective view of the reinforcing cross member that is part of the front structure of the motor vehicle in [Fig.1] and extending fixedly between - [Fig.5] represents a partial perspective cross-sectional view of this reinforcing cross member taken along a vertical longitudinal section plane. Description of the implementation methods

[0024] Fig. 1 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 following description, and by convention, an orthogonal XYZ coordinate system comprising three axes perpendicular in pairs is defined with respect to this structure before 1, namely: - an X-axis, defining a longitudinal, horizontal direction, - a Y-axis, defining a horizontal, transverse direction, which, together 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 following description and with reference to the frame 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 structure before 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 within the scope of the invention. For example, "substantially vertical" indicates that a deviation of approximately 15 to 20° from a strictly vertical orientation is permitted within the scope of the invention.

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

[0031] Two front 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 in the shape of a rectangular parallelepiped and having an internal summit protrusion on which a corresponding end of a front front crossmember 30 of the vehicle (generally made of plastic) is fixed by screwing, 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 assembly.

[0033] With reference to [Fig.2], each front support 20 thus classically 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 dropped edge projecting in front of this main front wall 21 and comprising in particular two internal lateral walls 22A and external lateral walls 22B extending from the internal and external lateral edges of said main front wall 21.

[0034] The front structure 1 also includes 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 left one being shown in this [Fig.1]) extending in line with the lateral side rails 10.

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

[0036] In order to structurally reinforce these facade supports 20 and to improve in particular their resistance to bending, the front structure 1 also includes, in a known manner, two hollow reinforcing boxes 50 of substantially rectangular parallelepiped shape (only the one on the left being shown on 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 reinforcing boxes 50 are each interposed longitudinally between the main front wall 21 of a facade support 20 and the anchor plate 43 of a corresponding lateral absorber 42, being traversed by the longitudinal screws Vp

[0038] As illustrated by [Fig. 3] showing an exploded view, each hollow reinforcing 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 main wall substantially rectangular bordered along at least its upper and lateral sides by a dropped edge.

[0039] Each hollow reinforcing box 50 thus comprises: - a front front face 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 main front wall 21 of a corresponding facade support 20 and formed by the half-shell 50B; - an upper section 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 overlapping internal lateral walls 54A, 54B of the dropped 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 front faces 51 and rear faces 52 of each hollow reinforcing box 50 each have a plurality of respective passage holes 511, 521, these holes 511, 521 being aligned longitudinally in pairs, so as to allow the longitudinal screws Vi to pass through the boxes 50.

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

[0042] Advantageously, each hollow reinforcing box 50 can house several internal spacers (not shown) extending longitudinally between its two front faces 51, 52 at the level of the perimeter of its openings 511, 521 and being traversed by the longitudinal screws Vp

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

[0044] In order to improve the holding of each hollow reinforcing box 50, these front front faces 51 and rear faces 52 can each advantageously have, near their lower end, a respective fixing hole 513, 523, these holes 513, 523 being aligned longitudinally and through which is passed a screw not shown also passing through the main front wall 21 of a respective front support 20 and screwing into a nut welded on the rear face of this main front wall 21.

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

[0046] Below the side rails 10, the front structure 1 further comprises two cradle extensions 60 (only the left one being shown in this [Fig.1]) extending longitudinally on either side of the vehicle's powertrain compartment, 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 and two lateral absorbers 72 extending in line with the cradle extensions 60 and each fixed by screwing via an anchor plate 73 on the front end of the corresponding cradle extension 60.

[0048] The front structure 1 also includes two wing linings 80 (only the left one being shown in this [Fig.1]) extending longitudinally on either side of the vehicle's powertrain compartment and whose respective front ends are each fixed by screwing, via several transverse screws V2, to the external side wall 22B of a front support 20 corresponding, and according to the invention, to the external side 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 front 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 area of ​​attachment by said screws V2 of this wing lining 80), screwing itself in this case onto a nut E2 welded on the internal perimeter of the upper portion of the external side wall 55B of the half-shell 50B and interposed 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] Fixing each front end of a wing lining 80 to the corresponding hollow reinforcement box 50 also ensures, in the event of a low overlap frontal impact, better transmission of 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 reinforcing box 50 thus optimizes the mechanical strength of the facade support 20 and limits notably its structural deformation during such an impact.

[0052] In order to allow a portion of the forces to be absorbed by the lateral part opposite the impact of the front structure 1 of the vehicle, the latter may advantageously include a reinforcing cross member 90 extending transversely between the two hollow reinforcing boxes 50, in front of the front front cross member 30, and whose two ends are fixed by screwing to the summit portions of these boxes 50.

[0053] Reserved for example for certain high-end vehicle models, the addition of such a 90 reinforcement crossmember could thus make it possible to obtain a better rating in the low overlap frontal crash 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 reinforcing boxes 50 and with reference to [Fig.4], each end of this reinforcing cross member 90 includes an anchoring bracket 91 in the shape of an angle, comprising a front wall 911 and an upper wall 912 projecting from 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 bracket 91 has at least one oblong orifice 913 oriented transversely (in this case, two spaced transversely apart) and through which passes a respective screw V3 also through a corresponding orifice 515 provided in the upper part of the front front face 51 of a corresponding hollow reinforcement box 50 (see [Fig.3]) and screwed onto a nut E3 welded on the rear face of this front front face 51 (see [Fig.2]).

[0056] Similarly, 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 through which passes a respective screw V4 also through a corresponding orifice provided in the upper face 53 of a corresponding hollow reinforcing box 50 (this orifice being formed by two superimposed orifices 516A, 516B provided in the partially superimposed upper walls 53A, 53B of these half-shells 50A, 50B as illustrated by [Fig.3]) and screwing onto a nut not visible in the figures welded on the lower face of the upper wall 53A of the half-shell 50A.

[0057] It will be noted that 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 reinforcing boxes 50 due to the normal manufacturing tolerances of the different constituent parts of this structure before 1.

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

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

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

Claims

Demands

1. Front structure (1) of a motor vehicle comprising: - two lateral struts (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 lateral strut (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 and two lateral shock absorbers (42) extending in line with said struts (10) and each comprising an anchor plate (43) fixed by screwing via several longitudinal screws (Vi) to the main front wall (21) of said corresponding front support (20);- two hollow reinforcing boxes (50) each interposed longitudinally between the front face (21) of said facade support (20) and the anchoring plate (43) of said corresponding absorber (42) by being traversed 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 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 said corresponding hollow reinforcing box (50).

2. Front structure (1) according to claim 1, characterized in that each said hollow reinforcement box (50) comprises a front front face (51) pressed against the anchor plate (43) of a corresponding lateral absorber (42), a rear front face (52) pressed against the main front wall (21) of a corresponding front support (20), an upper panel (53) extending between the upper edges of said faces (51, 52), an internal lateral panel (54) extending between the internal lateral edges of said faces (51, 52), and an external lateral panel (55) extending between the external lateral edges of said faces (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 said respective front support (20), at least at the level of the area of ​​attachment by said transverse screws (V2) of said corresponding wing lining (80).

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

5. Front structure (1) according to any one of claims 2 to 4, characterized in that the front faces (51, 52) of each said hollow reinforcing box (50) each have, near their lower end, a respective fixing hole (513, 523), said fixing holes (513, 523) of said faces (51, 52) being aligned longitudinally and through which is passed a screw also passing through the main front wall (21) of a respective front support (20) and screwing into a nut welded to the rear face of this main front wall (21).

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

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

8. Front structure (1) according to claim 7, characterized in that said reinforcing cross member (90) is made up of two pieces of stamped sheet metal (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 cross member (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 any one of claims 1 to 9.

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