Underbody assembly of a motor vehicle and motor vehicle comprising such an underbody assembly

Abstract

Underbody assembly of a motor vehicle and motor vehicle comprising such an underbody assembly. The invention relates to an underbody assembly (1) of a hybrid motor vehicle (3) comprising a thermal engine and an electric motor, said underbody assembly comprising: - a floor (5), comprising two half-floors (5a, 5b) separated by a central tunnel (7), - a battery support (11) designed to support an electric battery of said electric motor, fixed to said floor (5), - a reinforcing flange (19) of said central tunnel (7), fixed to said floor (5) and connecting the two half-floors (5a, 5b). According to the invention, the underbody assembly (1) comprises a coupling zone (27) between said battery support (11) and said reinforcing flange (19). The invention also relates to a motor vehicle comprising such an underbody assembly. Figure 1

Description

Title of the invention: Underbody assembly of a motor vehicle and motor vehicle comprising such an underbody assembly Technical field

[0001] The invention relates to the field of motor vehicles, in particular to the field of passive safety of the motor vehicle to provide protection in the event of a side impact and a frontal impact.

[0002] The invention relates more particularly to an underbody assembly of a motor vehicle and to a motor vehicle comprising such an underbody assembly. Prior art

[0003] Hybrid type motor vehicles comprise a heat engine and an electric motor which operate simultaneously or alternately so as to reduce the power consumed by the motor vehicle.

[0004] Among hybrid motor vehicles, some are of the "MHEV" type, an acronym for "Mild Hybrid Electric Vehicle", designating a light hybrid electric vehicle. This type of vehicle electrically assists the thermal engine, making it possible to support the thermal engine, particularly during the acceleration phases of the motor vehicle. This makes it possible to improve the vehicle's consumption and CO2 emissions.

[0005] For this purpose, the electric motor is equipped with an electric battery of relatively limited size located under the floor of the motor vehicle, under the driver's seat or under the passenger seat, generally between the central tunnel and the side member of an underbody structure.

[0006] The integration of the battery into the motor vehicle is for example carried out using a battery support onto which the battery is screwed. The support is itself screwed under the floor of the motor vehicle, close to a central tunnel reinforcement flange provided under the underbody of the motor vehicle in order to reinforce the central tunnel.

[0007] Among the plurality of tests used for the approval of motor vehicles, a so-called "pole" impact, also called "side impact" is carried out, in particular in order to reveal performance criteria relating to the protection of occupants.

[0008] This test consists of projecting the motor vehicle at a speed of approximately 30 km / h laterally against a rigid post, so that the vehicle defines an angle of approximately 75° relative to the post.

[0009] In the event of a side impact, the post becomes embedded in the motor vehicle at the level of the front door on the driver's side or passenger's side.

[0010] When the motor vehicle is subjected to such a side impact, the electric battery must be protected in order to avoid damage to the battery and limit the risk of fire.

[0011] Also, a large gap in rigidity exists between the battery support and the central tunnel reinforcement flange mounted near the battery support, leading in the event of a side impact to a risk of the appearance and propagation of an oblique fold which could cause the floor to tear.

[0012] Similarly, in the event of a frontal impact, the large difference in rigidity between the battery support and the central tunnel causes a risk of the floor shearing.

[0013] We know the prior art document FR3119595 which discloses a hybrid electric motor vehicle of the “MHEV” type, comprising a reinforcement device and / or an anchoring device consisting of elongated bodies arranged and fixed under the floor of the vehicle, extending in a direction forming an angle with the longitudinal direction of the vehicle. In this way, an additional force absorption path is created, making it possible to reduce the force experienced by the stretchers in the event of a frontal impact.

[0014] Also known is the prior art document FR3121906 which discloses a hybrid motor vehicle comprising a thermal and electric engine comprising a hollow body attached under one of the front seats between one of the side members and the central tunnel and extending over a distance greater than 50% of the distance between the side member and the central tunnel. In this way, a space is provided under one of the front seats, which makes it possible to provide the vehicle with a protective environment in the event of a side impact.

[0015] In all the solutions of the prior art, the use of added reinforcement parts is necessary to reinforce the area near the battery.

[0016] This increases the number of parts of the motor vehicle, which complicates the area of ​​the motor vehicle at the underbody level and makes the motor vehicle heavier. Statement of the invention

[0017] The present invention aims to overcome the aforementioned drawbacks, and to this end relates to an underbody assembly for a hybrid motor vehicle comprising a thermal engine and an electric engine, said assembly comprising: - a floor, comprising two half-floors separated by a central tunnel, - a battery support designed to support an electric battery of said motor electric, fixed to said floor, - a reinforcing flange of said central tunnel, fixed to said floor and connecting the two half-floors together, said underbody assembly being remarkable in that it comprises a coupling zone between said battery support and said reinforcing flange.

[0018] Thus, by providing a coupling zone between the battery support and the reinforcing flange, the forces experienced by the battery support when the motor vehicle is subjected to a side impact or a frontal impact are directly transmitted to the reinforcing flange.

[0019] In this way, the electric battery of the electric motor is protected against the risk of fire which may occur following deformation of the battery support, without having to resort to the use of added reinforcement parts as is the case in the prior art.

[0020] Furthermore, by transferring the forces undergone by the battery support to the reinforcing flange, the forces at the battery support are limited, which makes it possible to reduce the risk of shearing of the floor and therefore of tearing of the floor while also avoiding the need to provide added reinforcing parts.

[0021] Thus, thanks to the present invention, the underbody assembly is reinforced without adding reinforcing parts, which makes it possible to simplify the design of the underbody assembly and to limit the weight, and therefore the cost, of the motor vehicle equipped with such an underbody assembly.

[0022] According to optional characteristics of the base assembly according to the invention: - said coupling zone comprises an overlapping portion between said battery support and said reinforcing flange, said overlapping portion comprising a fixing orifice, made on said battery support, a fixing orifice, made on said reinforcing flange, a fixing element, received in said fixing orifices and adapted to ensure a connection between said battery support and said reinforcing flange; - said coupling zone extends at a right rear end of said battery support and at a left front end of said reinforcing flange; - said battery support comprises at least one transverse rib extending substantially transversely relative to said motor vehicle; - said at least one transverse rib extends substantially from a left lateral edge to a right lateral edge of said battery support; - said battery support comprises at least one longitudinal rib extending substantially longitudinally relative to said motor vehicle; - said at least one longitudinal rib is formed along a right lateral edge of said battery support; - said reinforcing flange has mechanical characteristics adapted to allow deformation of said reinforcing flange when said motor vehicle is subjected to a pole impact.

[0023] The invention also relates to a hybrid motor vehicle comprising a thermal engine and an electric engine, said vehicle comprising an underbody assembly, remarkable in that said underbody assembly is according to the invention. Brief description of the drawings

[0024] Other characteristics, aims and advantages of the invention will appear on reading the detailed description which follows, for the understanding of which reference will be made to the appended drawings in which:

[0025] [Fig-1] shows an underbody assembly of a motor vehicle according to the invention, seen from below.

[0026] [Fig.2] is an enlargement of zone II of [Fig. 1], with only the battery holder and the reinforcing flange being shown.

[0027] [Fig.3] is an enlargement of zone III of [Fig.2], seen in perspective.

[0028] [Fig.4] schematically represents the path of forces when the underbody assembly of the motor vehicle according to the invention is subjected to a lateral impact or a frontal impact. Description of the embodiments

[0029] In the remainder of the description, elements having an identical structure or similar functions are designated by the same reference.

[0030] We will adopt by convention, without limitation, longitudinal, vertical and transverse orientations indicated by the direct trihedron (L, V, T) designating the longitudinal, vertical and transverse axes of the vehicle.

[0031] In the following, the terms “left”, “right”, “lower” and “upper” are understood in relation to the vehicle.

[0032] Similarly, the terms “front” and “rear” are understood in relation to the general orientation of the vehicle as taken in its normal direction of travel.

[0033] Reference is made to [Fig.l] showing an underbody assembly 1 of a motor vehicle 3 according to the invention, seen from below.

[0034] The motor vehicle 3 is a hybrid motor vehicle, comprising a thermal engine and an electric engine, of the “MHEV” type, an English acronym for “Mild Hybrid Electric Vehicle”, designating a light hybrid electric vehicle.

[0035] The motor vehicle 3 comprises a heat engine (not shown) and an electric motor (not shown) which operate simultaneously or alternately so as to reduce the power consumed by the motor vehicle 3. For this purpose, the electric motor is equipped with an electric battery (not shown), which may for example be a 48V electric traction battery.

[0036] The electric battery, of relatively limited size, is located under a floor 5 of the underbody assembly 1, under the driver's seat or under the passenger seat.

[0037] The floor 5 comprises a right half-floor 5a and a left half-floor 5b separated by a central tunnel 7 extending longitudinally relative to the motor vehicle 3. The floor 5 is also bordered laterally by a right side member 9a and by a left side member 9b.

[0038] The electric battery is integrated into the motor vehicle 3 by means of a battery support 11, for example a sheet metal part, on which the battery is fixed, for example by screwing. In one embodiment, the battery support 11 may comprise an upper support plate and a lower support plate fixed together, for example by welding. The lower plate, facing the ground, makes it possible to protect the upper plate from external attacks suffered by the motor vehicle 3.

[0039] The battery support 11 is itself fixed to the floor 5 of the underbody assembly 1, for example by screwing. More particularly, the battery support 11 is fixed to the left half-floor 5b.

[0040] The battery holder 11 adopts a generally rectangular geometric shape, comprising a front edge 13, a rear edge 15, a right side edge 17a and a left side edge 17b.

[0041] In order to reinforce the central tunnel 7, the underbody assembly 1 comprises a reinforcing flange 19, connecting the right half-floor 5a to the left half-floor 5b. The reinforcing flange 19 has mechanical characteristics adapted to allow deformation of the reinforcing flange 19 when the motor vehicle 3 is subjected to a pole impact.

[0042] For this purpose, the reinforcing flange 19 is made of a material having a stiffness suitable for allowing such deformation.

[0043] Also, the reinforcing flange 19 is for example made of a sheet metal part, for example CP800 steel, with a thickness of between approximately 2mm and approximately 3mm, for example 2.5mm.

[0044] The reinforcing flange 19 is fixed to the floor 5 of the base assembly 1, for example by screwing.

[0045] The reinforcing flange 19 adopts a generally rectangular geometric shape, comprising a front edge 21, a rear edge 23, a right lateral edge 25a and a left lateral edge 25b.

[0046] According to the invention, the underbody assembly comprises a coupling zone 27 provided between the battery support 11 and the reinforcing flange 19.

[0047] Thus, the fact of providing a coupling zone between the battery support 11 and the reinforcing flange 19 makes it possible to transmit the forces undergone by the battery support 11 directly to the reinforcing flange 19 when the motor vehicle 3 is subjected to a side impact or a frontal impact.

[0048] In this way, it is possible to protect the electric battery of the electric motor against the risk of fire which may occur following deformation of the battery support 11, without having to resort to the use of added reinforcement parts as is the case in the prior art.

[0049] This limits the number of parts of the motor vehicle, which makes it possible to simplify the underbody assembly 1 and to limit the weight of the motor vehicle 3.

[0050] Furthermore, by transferring the forces undergone by the battery support 11 to the reinforcing flange 19, the forces at the level of the battery support 11 are limited, which makes it possible to reduce the risk of shearing of the floor and therefore of tearing of the floor while avoiding the need to provide added reinforcing parts.

[0051] Reference is made to Figures 2 and 3 showing respectively an enlargement of zone II of [Fig.l] and an enlargement of zone III of [Fig.2] seen in perspective, only the battery support 11 and the reinforcing flange 19 being shown.

[0052] In the embodiment illustrated in the figures, the coupling zone 27 comprises an overlapping portion between the battery support 11 and the reinforcing flange 19 in which the battery support 11 and the reinforcing flange 19 are coupled.

[0053] For this purpose, the covering portion of the coupling zone 27 comprises a fixing orifice 29 made on the battery support 11, a fixing orifice 31 made on the reinforcing flange 19 and a fixing element (not shown) received in the fixing orifices 29, 31 and adapted to ensure a connection between the battery support 11 and the reinforcing flange 19. The fixing element may consist of any fixing means allowing assembly between the battery support 11 and the reinforcing flange 19, for example a fixing screw.

[0054] Thus, the battery support 11 and the reinforcing flange 19 are fixed to the floor 5 of the underbody assembly 1 and they are also fixed together at the coupling zone 27.

[0055] The reinforcing flange 19 is for example positioned below the battery support 11, that is to say as close as possible to the ground.

[0056] In the embodiment illustrated in the figures and as best seen in [Fig.3], the coupling zone 27 extends at a right rear end 33 of the battery support 11 and at a left front end 35 of the reinforcing flange 19.

[0057] However, in the case where the battery support 11 is mounted under the passenger seat, that is to say under the right front seat, the coupling zone 27 would extend at a left rear end of the battery support 11 and at a right front end of the reinforcing flange 19.

[0058] In the embodiment illustrated in the figures, the battery support 11 comprises a set of transverse ribs 37 extending substantially transversely relative to the motor vehicle 3 when the battery support 11 is mounted in the motor vehicle 3, that is to say substantially transversely relative to the battery support 11.

[0059] The presence of the transverse ribs 37 makes it possible to further improve the transfer of forces from the battery support 11 to the reinforcing flange 19 when the motor vehicle 3 is subjected to a lateral impact.

[0060] For this purpose, the transverse ribs 37 extend substantially from the left lateral edge 17b of the battery support 11 to the right lateral edge 17a of the battery support 11.

[0061] The number and size of the transverse ribs 37 can be adapted according to the dimensioning of the battery support 11 and the forces to be transmitted.

[0062] According to an alternative embodiment not shown in the figures, a single transverse rib is made on the battery support 11.

[0063] According to another variant embodiment not shown in the figures, the battery support 11 does not have any transverse rib.

[0064] Also, in the embodiment illustrated in the figures, the battery support 11 comprises a longitudinal rib 39 extending substantially longitudinally relative to the motor vehicle 3, and therefore substantially longitudinally relative to the battery support 11.

[0065] The presence of the longitudinal rib 39 makes it possible to further improve the transfer of forces from the battery support 11 to the reinforcing flange 19 when the motor vehicle 3 is subjected to a frontal impact. For this purpose, the longitudinal rib 39 is for example made along the right lateral edge 17a of said battery support 11, in the immediate vicinity of the right lateral edge 17a.

[0066] Reference is made to [Fig.4] schematically illustrating the path of forces when the underbody assembly 1 is subjected to a lateral impact or a frontal impact.

[0067] When the motor vehicle 3 is subjected to a lateral impact, a lateral force 41 is experienced by the battery support 11.

[0068] A portion of the lateral force 41 then passes through the coupling zone 27 provided between the battery support 11 and the reinforcing flange 19, via the fixing element present between the fixing orifices 29, 31.

[0069] When the battery support 11 comprises the transverse ribs 37, the transverse ribs 37 improve the transfer of forces from the battery support 11 to the reinforcing flange 19.

[0070] The reinforcing flange 19 thus takes up part of the lateral force 41, as represented by the arrow 43. The reinforcing flange 19 then deforms taking into account its mechanical characteristics, which makes it possible to attenuate the deformation of the central tunnel 7 and to avoid tearing of the battery support 11.

[0071] In the same way, when the motor vehicle 3 is subjected to a frontal impact, a frontal force 45 is experienced by the battery support 11.

[0072] A portion of the frontal force 45 then passes towards the reinforcing flange 19 via the coupling zone 27.

[0073] The transfer of forces from the battery support 11 to the reinforcing flange 19 is further improved when the battery support 11 comprises the longitudinal rib 39.

[0074] The reinforcing flange 19 thus takes up part of the frontal force 45, as represented by the arrows 47.

[0075] Thus, thanks to the present invention, it is possible to transfer a significant portion of the energy generated by a frontal or lateral impact, from the battery support 11 to the reinforcing flange 19 without having to resort to one or more added reinforcing pieces.

[0076] Thus, the electric battery is protected against the risk of fire which could be caused following the impact and the risk of shearing of the floor is reduced, while avoiding the presence of added reinforcement parts.

[0077] The weight of the base assembly 1 is therefore limited as well as the cost of such an assembly. Also, the design of such a base assembly 1 is simplified.

[0078] As goes without saying, the present invention is not limited to the sole embodiments of this motor vehicle underbody assembly and of this motor vehicle comprising such an underbody assembly, described above solely as illustrative examples, but on the contrary it embraces all the variants involving the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

Claims

Claims

1. Underbody assembly (1) of a hybrid motor vehicle (3) comprising a thermal engine and an electric engine, said underbody assembly (1) comprising: - a floor (5), comprising two half-floors (5a, 5b) separated by a central tunnel (7), - a battery support (11) designed to support an electric battery of said electric motor, fixed to said floor (5), - a reinforcing flange (19) of said central tunnel (7), fixed to said floor (5) and connecting together the two half-floors (5a, 5b), said underbody assembly (1) being characterized in that it comprises a coupling zone (27) between said battery support (11) and said reinforcing flange (19).

2. Underbody assembly (1) according to claim 1, characterized in that said coupling zone (27) comprises an overlap portion between said battery support (11) and said reinforcing flange (19), said overlap portion comprising: - a fixing orifice (29), made on said battery support (11), - a fixing orifice (31), made on said reinforcing flange (19), - a fixing element, received in said fixing orifices (29, 31) and adapted to ensure a connection between said battery support (11) and said reinforcing flange (19).

3. Underbody assembly (1) according to one of claims 1 or 2, characterized in that said coupling zone (27) extends at a right rear end (33) of said battery support (11) and at a left front end (35) of said reinforcing flange (19).

4. Underbody assembly (1) according to any one of claims 1 to 3, characterized in that said battery support (11) comprises at least one transverse rib (37) extending substantially transversely relative to said motor vehicle (3).

5. Underbody assembly (1) according to claim 4, characterized in that said at least one transverse rib (37) extends substantially from a left lateral edge (17b) to a right lateral edge (17a) of said battery support (11).

6. Underbody assembly (1) according to any one of claims 1 to 5, characterized in that said battery support (11) comprises at least one longitudinal rib (39) extending sen- possibly longitudinally relative to said motor vehicle (3).

7. Underbody assembly (1) according to claim 6, characterized in that said at least one longitudinal rib (39) is formed along a right lateral edge (17a) of said battery support (11).

8. Hybrid motor vehicle (3) comprising a thermal engine and an electric engine, said vehicle comprising a base assembly (1) and being characterized in that said base assembly (1) is according to any one of claims 1 to 7.

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