MOTOR VEHICLE WITH CLOSELY PLACED STRETCHERS AND COMPATIBLE WITH LOW FRONT IMPACT ATTACK

Abstract

MOTOR VEHICLE WITH CLOSE-SET STRETCHERS AND COMPATIBLE WITH LOW-OVERLAP FRONT IMPACT. The present invention relates to a motor vehicle comprising, on each left and right side, a longitudinal beam (2) extending forward from a passenger compartment of said motor vehicle, and a deformable box (4) fixed to a front end (6) of the longitudinal beam. The motor vehicle is notable in that, on at least one of the left and right sides, the deformable box and the longitudinal beam form external lateral faces (7, 8) having a horizontal profile with a projection (10) at a front portion (6) of the longitudinal beam such that said external lateral face (8) of the deformable box is offset laterally outward by at least 100 mm relative to said external lateral face (7) of the longitudinal beam at the rear of the projection. (Figure to be published with the abbreviation: Figure 1)

Description

Title of the invention: MOTOR VEHICLE WITH CLOSELY PLACED AND COMPATIBLE STRETCHERS FOR LOW-OVERLAP FRONT IMPACT ATTACKS technical field

[0001] The present invention relates to the field of motor vehicles, more particularly to the field of motor vehicle structure. Previous technique

[0002] Structures designed for electric vehicles have a reduced powertrain footprint in the transverse direction. This reduction is due to the fact that electric motors are less bulky than internal combustion engines. Specifically, this allows the longitudinal beams, commonly referred to as frame members, to be brought closer together along the transverse axis, thus recentering them relative to the front transverse beam. This also allows the cross-section of these longitudinal beams to be increased or maintained constant along their entire length, thereby increasing their load-bearing capacity. Another advantage of bringing the longitudinal beams closer together is the ability to increase the wheel footprint and thus reduce the turning radius, which contributes to improved driving comfort in urban environments.

[0003] Furthermore, the ability of a motor vehicle to ensure the safety of its occupants in the event of a collision is evaluated by crash tests following various protocols. Among these protocols is the frontal impact protocol against a rigid wall with 100% overlap, commonly known as the high-overlap frontal impact protocol. Indeed, recentering the longitudinal beams relative to the front transverse beam improves the results of crash tests following high-overlap frontal impact protocols.

[0004] However, among the various collision protocols, there is also the frontal impact protocol against a stationary barrier with 25% overlap, commonly called the low overlap frontal impact protocol, which consists of impacting a vehicle at a speed of 64 km / h against a stationary barrier called a buffer, the width of which is 25% of the width of the vehicle impacted. During the low overlap frontal impact protocol, the recentering of the longitudinal beams relative to the front transverse beam prevents said longitudinal beams from fulfilling their role in damping the force of the impact. In this configuration, the longitudinal beams are no longer positioned facing the barrier, causing the outer lateral face of the longitudinal beam, instead of being compressing to absorb the shock of the impact, slides along the bumper, thus giving very unfavorable results in crash tests following low overlap frontal impact protocols.

[0005] The published patent document FR 3 038 574 Al proposes a vehicle structure comprising a reinforcement element at the edge of the front wheel arch so as to extend along between the frame rail and the side member, said reinforcement being intended to prevent the penetration of the front wheel into the floor in the event of a collision, in other words, the objective of the reinforcement as disclosed in patent FR 3 038 574 B1 is to prevent the absorption of the energy of the frontal collision by the floor of the vehicle, therefore said reinforcement must have high rigidity to cause the vehicle to deflect in the transverse direction in the event of a frontal collision, which will not allow a favorable result to be obtained in the frontal collision protocol with 25% overlap in the case where the structure concerned belongs to an electric traction motor vehicle.

[0006] The published patent document FR 3 096 005 Al discloses a motor vehicle shock absorption system intended to replace deformation boxes and ensure a direct link between the transverse front shock beam and the shafts, said reinforcement as described in patent FR 3 096 005 Al not being suitable for the structure of an electric traction motor vehicle having closely spaced longitudinal beams. Description of the invention

[0007] The present invention aims to overcome at least one of the drawbacks of the aforementioned prior art. More particularly, the invention aims to improve the behavior of a motor vehicle with a compact powertrain, such as an electric powertrain, in frontal collision protocols, particularly the low overlap frontal impact protocol, in an economical manner and without significant weight increase.

[0008] For this purpose, the invention relates to a motor vehicle comprising on each left and right side a longitudinal beam extending forward from a passenger compartment of said motor vehicle a deformable box fixed to a front end of the longitudinal beam; remarkable in that on at least one of the left and right sides, the deformable box and the longitudinal beam form external lateral faces having a horizontal profile with a step at a front part of the longitudinal beam such that said external lateral face of the deformable box is offset laterally outwards by at least 100 mm relative to said external lateral face of the longitudinal beam at the rear of the step.

[0009] According to one embodiment, the horizontal profile of the outer lateral face of the deformable box is straight and longitudinal. The deformable box may, however to present transverse impressions designed to promote accordion or "baling" compression in the event of a frontal impact.

[0010] According to one embodiment, the step extends rearward from the front end of the longitudinal beam over a length between 1 / 4 and 1 / 3 of a length of said longitudinal beam between said front end and the passenger compartment.

[0011] According to one embodiment, the step is curved with a radius of curvature which gradually decreases from a front end to a rear end of said step.

[0012] According to one embodiment, the outer lateral face of the deformable box girder and / or the outer lateral face of the longitudinal beam at the step(s) have a cross-section with a longitudinal central rib. The longitudinal central rib advantageously projects laterally outwards.

[0013] According to one embodiment, the deformable box comprises a main profile and an expanding profile disposed laterally to the main profile and forming the outer lateral face of said deformable box.

[0014] According to one embodiment, the main profile of the deformable box has a rectangular cross-section with a top face and a bottom face, and the corresponding widening profile has a horizontal U-shaped cross-section with two horizontal wings attached to the top and bottom faces of said main profile.

[0015] According to one embodiment, the longitudinal beam comprises a main profile and an expanding profile arranged laterally to the main profile and forming the outer lateral face with a step of said longitudinal beam.

[0016] According to one embodiment, the main profile of the longitudinal beam has a rectangular cross-section with an upper vertical junction rebate and a lower vertical junction rebate, and the corresponding widening profile has a horizontal U-shaped cross-section with two vertical flanges fixed to said upper and lower vertical junction rebates, respectively.

[0017] According to one embodiment, the longitudinal beam includes at its front end a rear fixing plate and the deformable box includes at a rear end a front fixing plate fixed to the rear fixing plate, the widening profile of the deformable box, if applicable, being directly fixed to said front fixing plate and / or the widening profile of the longitudinal beam, if applicable, being directly fixed to said rear fixing plate.

[0018] The measures of the invention are interesting in that they allow the two longitudinal beams, commonly referred to as stretchers, to be brought closer together, particularly when the vehicle includes a small powertrain such as an electric powertrain, while maintaining an effective width, at the level of the front bumper crossbeam, capable of withstanding forces of Low overlap frontal impact. Bringing the two longitudinal beams closer together is advantageous in particular because it increases the space available for the front wheels and, therefore, reduces the turning radius, and also provides more dimensional freedom for the sections of the two longitudinal beams.

[0019] The outward lateral offset of the side face of the deformable box relative to the outer side face of the longitudinal beam at the rear of the step can be integrated into the design of said longitudinal beam and said deformable box, or achieved by adding widening profiles as defined above. This second solution has the advantage of adapting an existing design. Brief description of the drawings

[0020] [Fig-1] represents a top view of a vehicle structure according to the invention during a low overlap forward shock protocol;

[0021] [Fig.2] represents the assembly of the deformable box girder to the longitudinal beam according to the invention;

[0022] [Fig.3] is a partial perspective view of the inner side of the assembly of the deformable box with longitudinal beam according to the invention; Detailed description

[0023] Figure 1 illustrates a top view of a motor vehicle structure according to the invention during a low-overlap frontal impact protocol against a bumper 1. The motor vehicle comprises, on each left and right side, a longitudinal beam 2, commonly referred to as a frame, extending forward from a passenger compartment of said motor vehicle, and a deformable box 4, commonly referred to by the English term "crashbox" due to its capacity to absorb frontal impacts experienced by the vehicle. The deformable box 4 is rigidly connected to a front transverse beam 3 and to a front end 6 of the longitudinal beam 2.

[0024] On at least one of the left and right sides of the motor vehicle, the longitudinal beam 2 and the deformable box 4 form external lateral faces 7, 8 having a horizontal profile with a step 10 at a front part of the longitudinal beam 2 such that said external lateral face 8 of the deformable box 4 is laterally offset outwards relative to said external lateral face 7 of the longitudinal beam at the rear of the step 10. This offset is at least 100 mm, advantageously at least 110 mm.

[0025] The horizontal profile of the outer lateral face 7 at the rear of the step 10 along a longitudinal direction is generally straight.

[0026] To simplify [Fig. 1], the bumper 1 and the various offsets are shown only on one side of the vehicle; similarly, some elements are not identified that only on one side, in particular for the step 10, what is detailed for one side (left or right) of the vehicle on the [Fig.l] is valid for the other side by symmetry.

[0027] The offset (X) of at least 100 mm is measured from the outer side face 7, at the rear of the spring, to the outer side face 8 of the deformable box girder 4 in a transverse direction. Preferably, the measurement of the offset (X) at the rear of the spring 10 is taken from the longitudinal position of the axis 13 of the front axle of the motor vehicle. In this respect, the offset (X) is within a range varying from 100 mm up to (X + a), (a) being the distance between the outer face 8 of the deformable box girder 4 and a lateral end 5 of the front crossbeam 3.

[0028] According to one embodiment, the horizontal profile of the outer lateral face 8 of the deformable box 4 is generally straight and longitudinal. It should be noted that the deformable box may, however, exhibit transverse indentations or deformations that promote its accordion-like compression in the event of a frontal impact.

[0029] According to one embodiment, the step 10 extends rearward from the front end 6 of the longitudinal beam 2 over a length between 1 / 4 and 1 / 3 of a length of said longitudinal beam 2 between said front end 6 and the passenger compartment.

[0030] The step 10 is curved and may have a radius of curvature which gradually decreases from a front end 11 to a rear end 12 of said step.

[0031] Figure 2 illustrates the assembly of the deformable box 4 to the longitudinal beam. The lateral offset towards the outside of the side face 8 of the deformable box relative to the outer side face of the longitudinal beam at the rear of the step is achieved by adding widening profiles 20 and 30, thus allowing adaptation of an existing design.

[0032] The right part of [Fig.2] is a cross-sectional view of the left part of [Fig.2] along a plane transverse to the deformable box 4.

[0033] With reference to the right part of [Fig.2], the outer lateral face 8 of the deformable box 4 has a cross-section with a longitudinal central rib 14.

[0034] The deformable box 4 comprises a main profile 16 and the widening profile 20 disposed laterally to the main profile 16 and forming the outer lateral face 8 of said deformable box 4.

[0035] Preferably, the widening profile 20 is made of DP steel, an acronym for the English name "Dual Phase," which is a steel consisting of a martensitic (hard) phase dispersed in a ferritic (ductile) matrix. DP steel is characterized by fatigue resistance and energy absorption capacity, making it suitable for structural parts of automotive bodywork, the 20 widening profile has a thickness ranging from 1.2 mm to 1.8 mm.

[0036] According to one embodiment, the main profile 16 of the deformable box 4 has a rectangular cross-section with a lower face 15 and an upper face 17, and the corresponding widening profile 20 has a horizontal U-shaped cross-section with two horizontal wings 18, 19 fixed to the lower face 15 and upper face 17 of said main profile 16.

[0037] Preferably, the means for fixing the two horizontal wings 18, 19 of the widening profile 20 with the lower face 15 and upper face 17 of the main profile 16 are formed by welding.

[0038] With reference to the left part of [Fig.2], the longitudinal beam 2 comprises a main profile 26 and the widening profile 30 arranged laterally to the main profile 26 and forming the outer lateral face 7 with step 10 of the longitudinal beam 2.

[0039] Preferably, the widening profile 30 is made of DP steel, an acronym for the English name "Dual Phase", having a thickness ranging from 1.5 mm to 2 mm.

[0040] The outer lateral face 7 of the longitudinal beam 2 at the step 10 also has a cross section with the central longitudinal rib 14.

[0041] According to one embodiment, the main profile 26 of the longitudinal beam 2 has a rectangular cross-section with a lower vertical junction rebate 32 and an upper vertical junction rebate 34, and the corresponding widening profile 30 has a horizontal U-shaped cross-section with two vertical flanges 29, 28 fixed to said upper vertical junction rebates 34 and lower vertical junction rebates 32.

[0042] Preferably, the means for fixing the two vertical wings 29, 28 belonging to the widening profile 30 with the upper vertical junction rebates 34 and lower vertical 32 belonging to the longitudinal beam 2, are formed by welding.

[0043] The longitudinal beam 2 includes at its front end 6 a rear fixing plate 36 and the deformable box 4 includes at a rear end a front fixing plate 38 fixed to the rear fixing plate 36, the widening profile 20 of the deformable box 4, where applicable, being directly fixed to said front fixing plate 38 and / or the widening profile 30 of the longitudinal beam 2, where applicable, being directly fixed to said rear fixing plate 36.

[0044] Preferably, the rear mounting plate 36 and the front mounting plate 38 are made of steel with a thickness of 2 mm.

[0045] Preferably, the means for fixing the widening profile 20 to the front joining plate 38 are formed by welding. Similarly, the means for fixing the The 30 longitudinal beam 2 widening profile with the rear joining plate 36 are formed by welding.

[0046] Advantageously, the front junction plate 38 is screwed to the rear junction plate 36.

[0047] Fig. 3 illustrates a partial perspective view of the inner side of the widening profile 20, 30 comprising an internal reinforcing partition 40 rigidly connected to an inner lateral surface 9 of said widening profile 20, 30. Preferably, the internal reinforcing partition 40 is welded to the inner lateral surface 9.

[0048] Preferably, the internal reinforcing partition 40 has a flat surface parallel to the rear junction plate 36 and / or the front junction plate 38.

[0049] Advantageously, the overlap (R) between the bumper 1 (as shown in [Fig. 1]) and the deformable box according to the invention is considered satisfactory, thus preventing a potential sliding phenomenon of the bumper along the deformable box. The longitudinal beam and the deformable box of the present invention allow the motor vehicle to achieve favorable results in a frontal impact protocol with 25% overlap, thanks to the improved overlap (R) of the present invention, which maximizes the absorption of the frontal impact energy by the deformable box and the longitudinal beam.

[0050] The invention allows for a weight reduction of up to 8 kg in the vehicle, thanks to improved load transfer efficiency in the two longitudinal beams. Furthermore, a reduction in the vehicle's overhang of up to 30 mm is another advantage of the invention.

Claims

Demands

1. A motor vehicle comprising, on each left and right side: - a longitudinal beam (2) extending forward from a passenger compartment of said motor vehicle; - a deformable box (4) fixed to a front end (6) of the longitudinal beam (2); characterized in that, on at least one of the left and right sides, the longitudinal beam (2) and the deformable box (4) form external lateral faces (7, 8) having a horizontal profile with a step (10) at a front part of the longitudinal beam (2) such that said external lateral face (8) of the deformable box (4) is laterally offset outwards by at least 100 mm relative to said external lateral face (7) of the longitudinal beam at the rear of the step (10),said deformable box (4) comprises a main profile (16) and an extension profile (20) arranged laterally to the main profile (16) and forming the outer lateral face (8) of said deformable box, said main profile (16) of said deformable box (4) having a rectangular cross-section with a lower face (15) and an upper face (17), and said corresponding extension profile (20) having a horizontal U-shaped cross-section with two horizontal flanges (18, 19) fixed to the lower (15) and upper (17) faces of said main profile (16).

2. Motor vehicle according to claim 1, wherein the horizontal profile of the outer side face (8) of the deformable box (4) is straight and longitudinal.

3. Motor vehicle according to any one of claims 1 and 2, wherein the step (10) extends rearward from the end of the front part (6) of the longitudinal beam (2) over a length between 1 / 4 and 1 / 3 of a length of said longitudinal beam (2) between said front end (6) and the passenger compartment.

4. Motor vehicle according to any one of claims 1 to 3, wherein the spring (10) is curved with a radius of curvature which gradually decreases from a front end (11) to a rear end (12) of said spring.

5. Motor vehicle according to any one of claims 1 to 4, wherein the outer side face (8) of the deformable body (4) and / or the outer lateral face (7) of the longitudinal beam (2) at the step (10) has a cross section with a central longitudinal rib (14).

6. Motor vehicle according to any one of claims 1 to 5, wherein the longitudinal beam (2) comprises a main profile (26) and an expanding profile (30) arranged laterally to the main profile (26) and forming the outer lateral face (7) with step (10) of said longitudinal beam (2).

7. Motor vehicle according to claim 6, wherein the main profile (26) of the longitudinal beam (2) has a rectangular cross-section with a lower vertical joining rebate (32) and an upper vertical joining rebate (34), and the corresponding widening profile (30) has a horizontal U-shaped cross-section with two vertical wings (29, 28) attached to said upper (34) and lower (32) vertical joining rebates.

8. Motor vehicle according to any one of claims 1, 6, 7, wherein the longitudinal beam (2) comprises at its front end (6) a rear mounting plate (36) and the deformable box (4) comprises at a rear end a front mounting plate (38) fixed to the rear mounting plate (36), the widening profile (20) of the deformable box (4), if applicable, being directly fixed to said front mounting plate (38) and / or the widening profile (30) of the longitudinal beam (2), if applicable, being directly fixed to said rear mounting plate (36).

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