Body structure for motor vehicle

Abstract

The invention relates to a body structure (1) for a motor vehicle (2), the body structure (1) comprising a lateral longitudinal member (11) connected to a rear cross member (12) which extends in a secant manner to the lateral longitudinal member (11) in the direction of another lateral longitudinal member (11) of the body structure (1), the rear cross member (12) being fixed by each of its ends to a rear part (18) of the lateral longitudinal member (11), a rear wheel set (13) secured to the lateral longitudinal member (11) and located close to the rear cross member (12). According to the invention, the body structure (1) further comprises a side member reinforcement (14) which extends from the rear part (18) of the side member (11), the side member reinforcement (14) extending, at a distance – along the transverse axis (Y) – from the side member (11) between said rear part (18) and the rear wheel set (13). Figure to be published with the abstract: Fig. 1

Description

Title of the invention: Body structure for a motor vehicle

[0001] The technical context of the present invention is that of motor vehicle chassis, and in particular those equipped with means of protection against their deformation in the event of a collision. More particularly, the invention relates to a body structure for a motor vehicle.

[0002] As is known, motor vehicles are equipped with a chassis forming a body structure generally comprising at least lateral side members braced by cross members. The lateral side members extend longitudinally between the front and the rear of the body structure, along each lateral side thereof. The cross members are oriented transversely to the lateral side members, each cross member extending between the two lateral side members. The lateral side members and / or the cross members are commonly formed from steel profiles giving the body structure its robustness.

[0003] A current trend also lies in the development of electrified motor vehicles, whether they are exclusively electric-powered or equipped with a hybrid engine. Since such electrified vehicles must carry electric batteries necessary for the electrical supply of an electric motor, their mass increases significantly. Such increases in mass lead to resizing or imagining new architectures for body structures, so that the mechanical stresses resulting from an accident can be absorbed or transmitted by them while preserving the integrity of the passenger compartment and the safety of its occupants.

[0004] In the state of the art, known body structures comprise structural protection elements which comprise both shock absorption systems for dissipating the mechanical energy resulting from impacts, and transmission paths for these forces through the body structures in order to preserve the passenger compartment of the motor vehicle as much as possible. Among these structural protection elements intended to improve the passive safety of motor vehicles, an upper path is identified which passes through a roof of the motor vehicles, and a lower path which passes through the chassis of said motor vehicles. In the state of the art, the transmission of mechanical forces arising from an impact via the lower path is preferred.

[0005] Also, in this context of both the electrification of motor vehicles, leading to an increase in their mass, and the compactification of said motor vehicles, the design constraints of the various body structure elements are increasingly stringent in order to best resolve these technical problems. sometimes contradictory to each other. In particular, in the case of motor vehicles of the "coupe" type, the spaces available at the rear area are very limited and subject to significant mechanical constraints in the event of a rear impact. Also, a general technical problem of the invention aims to reinforce the body structure at the rear area of the motor vehicle.

[0006] The object of the present invention is to propose a new body structure for a motor vehicle in order to respond at least to a large extent to the preceding problems and to further lead to other advantages.

[0007] Another aim of the invention is to reinforce the rigidity of the side members at the level of a rear wheel assembly of the motor vehicle.

[0008] Another object of the invention is to limit or even prevent the rear wheel from pivoting towards the side member during a rear impact or a wheel impact on the side member. More generally, the invention aims to limit the damage caused by an impact in the rear zone of the motor vehicle on the rear wheel assembly of said motor vehicle.

[0009] According to a first aspect of the invention, at least one of the aforementioned objectives is achieved with a body structure for a motor vehicle, the body structure comprising:

[0010] - a lateral side member extending along a longitudinal axis of the motor vehicle;

[0011] - a rear cross member which extends along a transverse axis of the motor vehicle, one end of the rear cross member being securely fixed to a rear part of the side member;

[0012] - a rear wheel assembly secured to the side member and located near the rear cross member.

[0013] According to the invention, the body structure further comprises a side member reinforcement which extends from the rear part of the side member, the side member reinforcement extending at a distance from the side member between said rear part and the rear wheel set.

[0014] In the context of the present invention, a longitudinal axis, a lateral axis and a vertical axis are defined relative to the motor vehicle on which the body structure according to the first aspect of the invention is intended to be mounted. More particularly, the transverse axis is understood as a direction taken between a lateral side of the motor vehicle and an opposite lateral side of said motor vehicle. In other words, the transverse axis is understood as a direction which extends from a passenger side of the motor vehicle to a driver's side of said motor vehicle, or vice versa. The adjectives lateral, inboard and outboard refer to such a transverse axis. Furthermore, the longitudinal axis extends as being taken along a direction which extends from front to rear or from back to front of the motor vehicle. The longitudinal axis is perpendicular to the transverse axis. The adjectives frontal, front and rear refer to this longitudinal axis. Finally, the vertical axis is understood to be taken along an axis that extends from the wheels of the motor vehicle and towards the roof of said motor vehicle, or vice versa, the vertical axis being simultaneously perpendicular to the transverse axis and to the longitudinal axis. The adjectives above and below, or lower and upper refer to this vertical axis.

[0015] In the context of the present invention, the body structure is an underbody frame of the motor vehicle.

[0016] In the context of the present invention, the lateral side member forms a prismatic span which extends relative to the longitudinal axis of the motor vehicle, at each lateral edge of said motor vehicle. The lateral side members form structural elements of the motor vehicle to which other parts of the motor vehicle are attached. The lateral side members thus make it possible to provide the rigidity necessary for the operation of the motor vehicle, during driving sequences, but also in the event of an accident in order to transmit the forces resulting from said impact towards absorption devices or towards the running gear of the motor vehicle for example. The lateral side members are generally formed from steel profiles giving the body structure its robustness.

[0017] In the context of the present invention, the crossmember is a beam - straight or curved - which extends mainly along the transverse axis. The crossmember is fixed integrally by its lateral ends to the lateral side members of the body structure of the motor vehicle. The crossmember thus forms a spacer device for the lateral side members. The body structure of the motor vehicle comprises one or more crossmembers connecting the lateral side members, the crossmembers being distributed along the longitudinal axis. Each crossmember thus makes it possible to provide the rigidity necessary for the operation of the motor vehicle, during driving sequences, but also to transmit the mechanical forces resulting from an impact to each lateral side member and towards the body structure of the motor vehicle. Each crossmember is generally formed from a steel profile giving the body structure its robustness.

[0018] In the context of the present invention, the rear portion of the side rail comprises the portion of said side rail proximal to a rear bumper of the motor vehicle, relative to the longitudinal axis. The rear portion of the side rail is intended to be associated with a side rail support of the motor vehicle. The side rail support forms an interface zone between the side rail, the rear cross member and, henceforth, the side rail reinforcement.

[0019] In the context of the present invention, the side member reinforcement comprises a prismatic bearing surface which extends relative to the longitudinal axis of the motor vehicle, from the rear part of the side member and in the direction of the rear wheel assembly. The side member reinforcement is attached to the side member and associated with it in order to reinforce it. its rigidity. From a kinematic point of view, the spar reinforcement extends parallel to the lateral spar to which it is associated. Generally speaking, the spar reinforcement is formed from a profile, for example in steel, whose shape and dimensions can be variable depending on the desired effects and the constraints of available space.

[0020] Thus, the body structure according to the first aspect of the invention solves the technical problem in that it makes it possible to reinforce the rigidity of the side members at the level of a rear wheel assembly of the motor vehicle, thus contributing to reinforcing the safety of the occupants of the passenger compartment of the motor vehicle and to prevent the rear wheel assembly from being excessively damaged following an impact in the rear zone of said motor vehicle.

[0021] The body structure according to the first aspect of the invention advantageously comprises at least one of the improvements below, the technical characteristics forming these improvements being able to be taken alone or in combination:

[0022] - the side member has a curved section near the rear wheel assembly. More particularly, the curved portion of the side spar is located between the rear wheel set and the rear portion of said side spar. The curved portion of the side spar forms a curved portion along the vertical axis. Near the rear portion, the rear spar is located higher than a front portion of the rear spar located beyond the rear wheel set, relative to the longitudinal axis;

[0023] - the side member is located in an intermediate position between the rear cross member and the side member reinforcement. In other words, the side member reinforcement is located laterally outside the side member, relative to the body structure and to a median longitudinal axis of said body structure. This advantageous configuration makes it possible to provide additional protection for the side member in the event of a side impact and to reinforce the bending rigidity of said side member. In addition, this also makes it possible to better protect the rear wheel assembly located in the direct vicinity of the side member reinforcement;

[0024] - the spar reinforcement is attached to the side spar. The spar reinforcement is fixed integrally to the side rail and to a rear floor of the body structure. By way of non-limiting examples, the side rail reinforcement is fixed by bolting and / or by welding, in the context of the present invention, the rear floor comprises a thin mechanical sheet metal and fixed to the side rail. The rear floor extends transversely between a first side rail and a second side rail opposite the first side rail, relative to the transverse axis. The rear floor thus makes it possible to delimit from below the passenger compartment at the level of the rear zone of the body structure according to the first aspect of the invention;

[0025] - the spar reinforcement extends in a horizontal or substantially horizontal plane. More generally, the spar reinforcement extends in a plane intersecting with the curved portion of the side spar. The spar reinforcement extends above the curved portion of the side spar, relative to the longitudinal axis;

[0026] - the spar reinforcement extends in a curvilinear manner from the rear part of the side member. More particularly, in a horizontal plane formed by the longitudinal axis and the transverse axis, the side member reinforcement has a curvilinear shape, so that it extends concavely beyond the side member. This advantageous configuration makes it possible to force the side member reinforcement to deform in the direction of the side member in the event of an impact on the body structure, in order to be able to absorb the corresponding mechanical forces and better protect the rear wheel assembly. More particularly, the side member reinforcement takes the form of a finger which extends from the rear part of the side member and in the direction of the rear wheel assembly;

[0027] - the spar reinforcement delimits a light between the lateral spar and said reinforcement of side member. In the context of the present invention, the light forms an empty space delimited on the one hand by the side member and, on the other hand, by the side member reinforcement. The light thus forms a reserve for the deformation of the side member reinforcement in the event of an impact on the body structure, in order to be able to absorb the corresponding mechanical forces and better protect the rear wheel assembly;

[0028] - the spar reinforcement has a variable inertia relative to the long axis longitudinal, so as to promote pivoting around a vertical axis and in the direction of the side member in the event of a rear impact or side impact on the motor vehicle, this advantageous configuration allows the side member reinforcement to deform during an impact at the rear part of the body structure and, in doing so, to dissipate part of the mechanical energy resulting from the impact and transmitted by the body structure in accordance with the first aspect of the invention;

[0029] - according to a first embodiment, the spar reinforcement has a section variable transverse between a proximal portion of the rear portion of the side spar and a free end of the spar reinforcement. In particular, in this first embodiment, the spar reinforcement has a portion of lesser inertia along which a width - taken relative to the transverse axis - and / or a height - taken relative to the vertical axis - of the spar reinforcement is less than that of said spar reinforcement taken outside the portion of lesser inertia;

[0030] - according to a second alternative or complementary embodiment of the first embodiment, the spar reinforcement has a variable sheet thickness between a proximal portion of the rear portion of the side spar and a free end of the spar reinforcement. In particular, in this second embodiment, the spar reinforcement has a portion of lesser inertia along which a thickness of sheet metal forming said spar reinforcement is less than that of said spar reinforcement taken outside the portion of least inertia;

[0031] - the body structure comprises a closing plate extending between a free end of the side member reinforcement and the side member. This advantageous configuration makes it possible to form a retaining element for the free end of the side member reinforcement, thus facilitating the deformation of said side member reinforcement in the direction of the side member in the event of an impact on the rear part of the body structure;

[0032] - the closing plate is fixed securely to the side member reinforcement at the level of its free end, and at the level of the side member located opposite, the closing plate is fixed to the member by any means, and in particular by screwing and / or by bolting and / or by welding;

[0033] - the closing plate delimits the light relative to the longitudinal axis, to the level of the free end of the spar reinforcement;

[0034] - the closing plate takes the form of a sheet metal part, formed from a material metallic or comprising a metallic alloy, such as for example steel;

[0035] - in order to facilitate the deformation of the spar reinforcement in the direction of the spar lateral in the event of an impact against the rear part of the body structure according to the first aspect of the invention, the closing plate comprises at least one bending initiation configured to deform in the event of an impact. The at least one bending initiation is configured to cause the side member reinforcement to pivot in the direction of the lateral side member, in the event of an impact on the rear part of the body structure according to the first aspect of the invention. More particularly, the at least one bending initiation comprises at least one rib and / or at least one groove which extend relative to the vertical axis or substantially to said vertical axis. The at least one bending initiation of the closing plate is proximal to the side member reinforcement;

[0036] - in order to facilitate the deformation of the spar reinforcement in the direction of the spar lateral in the event of impact against the rear part of the body structure according to the first aspect of the invention, the closing plate has a section with variable inertia, relative to the transverse axis. In particular, a height of the closing plate taken from the side of the side member reinforcement is greater than a height of the closing plate taken from the side of the side member.

[0037] According to a second aspect of the invention, there is provided a motor vehicle comprising a body structure in accordance with the first aspect of the invention or according to any of its improvements.

[0038] Various embodiments of the invention are provided, integrating according to all of their possible combinations the different optional characteristics set out here.

[0039] Other characteristics and advantages of the invention will become apparent from the following description on the one hand, and of several examples of embodiment given for informational and non-limiting purposes with reference to the attached schematic drawings on the other hand, in which:

[0040] [Fig.l] illustrates a bottom view of an exemplary embodiment of a body structure of a motor vehicle, in accordance with the first aspect of the invention;

[0041] [Fig.2] illustrates a detail and perspective view of the illustrated body structure on [Fig.l].

[0042] Of course, the features, variants and different embodiments of the invention may be combined with each other, in various combinations, provided that they are not incompatible or mutually exclusive. In particular, variants of the invention may be imagined comprising only a selection of features described below in isolation from the other features described, if this selection of features is sufficient to confer a technical advantage or to differentiate the invention from the prior art.

[0043] In particular, all the variants and all the embodiments described can be combined with each other if nothing prevents this combination from a technical point of view.

[0044] In the figures, the elements common to several figures retain the same reference.

[0045] In the FIGURES described below, a longitudinal axis X, a lateral axis and a vertical axis Z are defined relative to the motor vehicle 2 on which the conforming body structure 1 is intended to be mounted.

[0046] More particularly, the transverse axis Y is understood as a direction taken between a lateral side of the motor vehicle 2 and an opposite lateral side of said motor vehicle 2. In other words, the transverse axis Y is understood in a direction which extends from a passenger side of the motor vehicle 2 to a driver's side of said motor vehicle 2, or vice versa. The adjectives lateral, interior and exterior refer to such a transverse axis Y.

[0047] Furthermore, the longitudinal axis X extends as taken along a direction that extends from front to rear or from back to front of the motor vehicle 2. The longitudinal axis X is perpendicular to the transverse axis Y. The adjectives frontal, front and rear refer to this longitudinal axis X.

[0048] Finally, the vertical axis Z is understood as being taken along an axis which extends from the wheels of the motor vehicle 2 and towards the roof of said motor vehicle 2, or vice versa, the vertical axis Z being simultaneously perpendicular to the transverse axis Y and to the longitudinal axis X. The adjectives above and below, or lower and upper refer to this vertical axis Z.

[0049] With reference to FIGURES 1 and 2, the invention addresses a body structure 1 for motor vehicle 2, the body structure 1 comprising:

[0050] - a lateral side member 11 extending along a longitudinal axis X of the vehicle at car 2;

[0051] - a rear cross member 12 which extends along a transverse axis Y of the vehicle to the car 2, one end of the rear cross member 12 being securely fixed to a rear part 18 of the side member 11;

[0052] - a rear wheel train 13 secured to the side member 11 and located near the cross member 12 rear;

[0053] - a spar reinforcement 14 which extends from the rear portion 18 of the side spar 11, the side member reinforcement 14 extending at a distance from the side member 11 between said rear part 18 and the rear wheel assembly 13.

[0054] In the embodiment illustrated in the FIGURES, the body structure 1 comprises two lateral side members 11 each located at a lateral side of the motor vehicle 2, the lateral side members 11 being connected to each other by one or more cross members 12 forming spacers. The invention relates more particularly to the connection of the lateral side members 11 to the rear cross member 12 of the body structure 1.

[0055] Although not limiting, the invention is particularly suitable for compact motor vehicles, for example of the type of a coupe or an urban sports vehicle. Their compactness in fact leads to technical problems linked to the dimensioning and the available space that the invention skillfully resolves. As illustrated in the FIGURES, when the lateral side members 11 have a curved section, so that the rear part 18 of the body structure 1 is greater than a front part of said body structure 1, the presence of the side member reinforcements 14 near the rear wheel set 13 makes it possible to stiffen this part of the body structure 1.

[0056] At this rear portion 18, the side member reinforcement 14 is connected to the side member 11, and the side member reinforcement 14 extends forwards towards the rear wheel assembly 13 and outside the side member 11, i.e. on a side opposite the passenger compartment of the motor vehicle 2 relative to the side member 11. The side member 11 forms with the side member reinforcement 14 a “Y” or “V” shaped portion, as can be seen more particularly in [Fig.l].

[0057] The spar reinforcement 14 is attached to the lateral spar 11 and fixed thereto by welding and / or by bolting and / or by screwing. Of course, in order to maximize the rigidity and the connection between the spar reinforcement 14 and the lateral spar 11, several fixing points are provided and distributed at the level of this rear part 18 forming the interface between the two parts.

[0058] The spar reinforcement 14, just like the lateral spar 11, form prismatic profiles, preferably hollow, in order to provide great axial rigidity, rela tively to their direction of elongation, as well as good bending strength. The spar reinforcement 14 and the lateral spar 11 comprise several grooves assembled to each other, possibly around a web, so as to form such a prismatic beam.

[0059] Advantageously, the side member reinforcement 14 is configured to allow, in the event of a sufficiently strong impact against the body structure 1, to deform in a particular manner. Indeed, in such circumstances, it is desired that the side member reinforcement 14 deforms in the direction of the lateral side member 11 with which it is associated, rather than moving away from it. This advantageous configuration is sought both to absorb the mechanical energy of the impact and to attenuate the residual forces transmitted to the rest of the body structure 1, but also in order to reduce the damage caused to the rear wheel set 13 located nearby.

[0060] For this purpose, the side member reinforcement 14 advantageously comprises a variable inertia profile, so that the inertia of the side member reinforcement 14 is greater on the side of a proximal portion 141 of the lateral side member 11 and of the rear portion 18, and so that said inertia is lower at a free end 142 of the side member reinforcement 14. The free end 142 of the side member reinforcement 14 is located opposite and close to the rear wheel set 13. By variable inertia, it is understood that the side member reinforcement 14 is more rigid at its end located on the side of the lateral side member 11, that is to say at the rear portion 18 of the body structure 1, while the side member reinforcement 14 is less rigid at its free end 142. As visible in [Fig.l] in particular, a width of the spar reinforcement 14, taken along the transverse axis Y, is greater at the proximal part 141 of the lateral spar 11 than at its free end 142. Advantageously, the spar reinforcement 14 comprises a middle part 143 which has a section of minimum width.

[0061] As visible in the FIGURES, the side member reinforcement 14 has a curved shape, in a horizontal plane. The side member reinforcement 14 extends from the proximal portion 141 of the rear portion 18 of the body structure 1, at a distance from the lateral side member 11, relative to the transverse axis Y, and thus delimiting a slot 16 between the side member reinforcement 14 and the lateral side member 11.

[0062] At its free end 142, the side member reinforcement 14 is connected to the lateral side member 11 by means of a closing plate 17 which delimits the central opening 16, relative to the longitudinal axis X and towards the front, the closing plate 17 takes the form of a metal plate fixed integrally both to the lateral side member 11 and to the side member reinforcement 14. The closing plate 17 makes it possible to prevent the side member reinforcement 14 from moving away from the lateral side member 11 in the event of an impact at the rear part 18 of the body structure 1.

[0063] In order to reinforce the pivoting of the side member reinforcement 14 towards the lateral side member 11 in the event of an impact at the rear part 18 of the body structure 1, the closing plate 17 comprises at least one bending incipient 171, taking the form of a rib or a groove extending along the vertical axis Z. In the embodiment illustrated in the FIGURES, the closing plate 17 comprises a single bending incipient 171, located in the direct vicinity of the side member reinforcement 14, and extending along the vertical axis Z. Thus, in the event of an impact at the rear part 18 of the body structure 1, the mechanical stresses will be localized at the bending incipient 171, leading to its elastic or plastic deformation, and leading to promoting a rotational movement of the free end 142 of the side member reinforcement 14 in the direction of the lateral side member 11, that is, inwards relative to the transverse axis Y.

[0064] The free end 142 of the side member reinforcement 14 and the closing plate 17 are located opposite the rear wheel assembly 13, relative to the longitudinal axis X.

[0065] In summary, the invention relates to a body structure 1 for a motor vehicle 2, the body structure 1 comprising a lateral side member 11 connected to a rear cross member 12 which extends in a secant manner to the lateral side member 11 in the direction of another lateral side member 11 of the body structure 1, the rear cross member 12 being fixed by each of its ends to a rear part 18 of the lateral side member 11, a rear wheel set 13 secured to the lateral side member 11 and located close to the rear cross member 12. According to the invention, the body structure 1 further comprises a side member reinforcement 14 which extends from the rear part 18 of the lateral side member 11, the side member reinforcement 14 extending, at a distance - along the transverse axis Y - from the lateral side member 11 between said rear part 18 and the rear wheel set 13.

[0066] Of course, the invention is not limited to the examples which have just been described and numerous adjustments can be made to these examples without departing from the scope of the invention. In particular, the different characteristics, forms, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or mutually exclusive. In particular, all the variants and embodiments described above can be combined with each other.

Claims

Claims

1. Body structure (1) for a motor vehicle (2), the body structure (1) comprising: - a lateral side member (11) extending along a longitudinal axis (X) of the motor vehicle (2); - a rear cross member (12) which extends along a transverse axis (Y) of the motor vehicle (2), one end of the rear cross member (12) being fixed integrally to a rear part (18) of the lateral side member (11); - a rear wheel assembly (13) integral with the lateral side member (11) and located close to the rear cross member (12); characterized in that the body structure (1) further comprises a side member reinforcement (14) which extends from the rear part (18) of the side member (11), the side member reinforcement (14) extending at a distance from the side member (11) between said rear part (18) and the rear wheel set (13).

2. Body structure (1) according to the preceding claim, in which the lateral side member (11) comprises a curved section near the rear wheel set (13), the curved portion of the lateral side member (11) being located between the rear wheel set (13) and the rear part (18) of said lateral side member (11).

3. Body structure (1) according to any one of the preceding claims, in which the side member reinforcement (14) is attached to the side member (11), the side member reinforcement (14) being fixed integrally to the side member (11) and to a rear floor (15) of the body structure (1).

4. Body structure (1) according to any one of the preceding claims, in which the side member reinforcement (14) takes the form of a finger which extends from the rear part (18) of the side member (11) and in the direction of the rear wheel set (13), the side member reinforcement (14) delimiting a slot (16) between the side member (11) and said side member reinforcement (14).

5. Body structure (1) according to any one of the preceding claims, in which the side member reinforcement (14) has a variable inertia relative to the longitudinal axis (X), so as to promote pivoting around a vertical axis (Z) and in the direction of the side member (11) in the event of a rear impact or side impact on the motor vehicle (2).

6. A body structure (1) according to any preceding claim, wherein the body structure (1) comprises a closure plate (17) extending between a free end (142) of the side member reinforcement (14) and the side member (11).

7. Body structure (1) according to the preceding claim, in which the closing plate (17) is fixed integrally to the side member reinforcement (14) at its free end (142), and at the side member (11) located opposite.

8. Body structure (1) according to any one of claims 6 or 7, in which the closing plate (17) comprises at least one bending initiation (171) configured to deform in the event of an impact, the at least one bending initiation (171) being configured to cause the side member reinforcement (14) to pivot in the direction of the lateral side member (H).

9. Body structure (1) according to the preceding claim, in which the at least one fold initiation (171) comprises at least one rib and / or at least one groove which extend relative to the vertical axis (Z) or substantially to said vertical axis (Z).

10. Motor vehicle (2) comprising a body structure (1) according to any one of the preceding claims.

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