Underbody assembly and motor vehicle comprising such an assembly

Abstract

Underbody assembly and motor vehicle comprising such an assembly. The invention relates to an underbody assembly for a motor vehicle, comprising:- a floor (5), comprising two half-floors,- a longitudinal central tunnel (7), extending between said half-floors,- at least one front seat crossmember, fixed to said floor and comprising a first end connected to said tunnel and a second end fixed to a longitudinal side member,- a heel board (23), mounted behind said at least one front seat crossmember, comprising a transverse face (27) extending perpendicularly relative to said floor (5).According to the invention, the underbody assembly comprises a force distribution device comprising at least one oblique rib (29, 31, 33, 35, 37) arranged on said transverse face (27) of said heel board (23) so as to approach said central tunnel (7).The invention also relates to a motor vehicle comprising such an underbody assembly. Figure 2.

Description

Title of the invention: Underbody assembly and motor vehicle comprising such an 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.

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

[0003] A motor vehicle body structure comprises a set of sheet metal structural elements providing stiffness to the motor vehicle, assembled together and forming the frame of the motor vehicle.

[0004] The body structure comprises, in particular, a left side structure and a right side structure. Each side structure comprises a set of upper and lower horizontal elements, extending substantially longitudinally relative to the body, and a set of vertical elements, extending substantially vertically relative to the body. The lower horizontal elements comprise lateral longitudinal side members defining a portion of the periphery of a body underbody assembly.

[0005] The body structure further comprises, among these sheet metal elements, a floor defining a part of the platform of the passenger compartment of the motor vehicle.

[0006] The floor comprises a right half-floor and a left half-floor, separated from each other by a central tunnel extending longitudinally relative to the motor vehicle and consisting of a hollow body. The floor is bordered laterally by the right and left side rails.

[0007] The underbody assembly further comprises a front seat cross member and a front seat rear cross member, extending transversely relative to the vehicle and connecting the right and left side members to the central tunnel.

[0008] 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.

[0009] This test consists of projecting the motor vehicle at a speed of approximately 32 km / h laterally against a rigid post, so that the vehicle defines an angle of approximately 75° relative to the post.

[0010] In the event of a side impact, the post becomes embedded in the motor vehicle at the level of the driver's side front door.

[0011] The side member, the first element of the underbody assembly of the motor vehicle to be impacted, is subjected to bending stress, causing the front and rear cross members of the front seat to be stressed.

[0012] This results in the appearance of folds oriented substantially at 45° on the front seating floor, the portion of floor on which the seats of the front row rest and adjoining the heel board, an intermediate transverse piece present between the seats of the front row and the seats of the rear row and on which the heels of the occupants of the rear row rest.

[0013] Bending the front seat floor causes the creases to propagate to the heel board, which is then stressed during a side impact.

[0014] However, an excessively large deformation amplitude of the heel board increases the risk of the post entering the passenger compartment of the motor vehicle.

[0015] This degrades the safety of the motor vehicle and limits the survival space of the occupants present on board the motor vehicle.

[0016] Document FR3026712B1 is known from the prior art, which discloses a means of reinforcing the heel board using reinforcements which double the upper angle of the heel board.

[0017] Document FR3040969B1 is also known, which discloses a heel board reinforced by means of ribs formed by a peripheral stamping and by a reinforcing piece forming a lining of the rear part of the heel board.

[0018] In these prior art solutions, the addition of an added reinforcement part is necessary, which goes against the recurring problem of reducing the mass of the motor vehicle.

[0019] Also, during a side impact, the fold propagates to the tunnel, which causes a bend in the heel board, increasing the risk of intrusion of the post into the passenger compartment in the event of a side impact. Statement of the invention

[0020] The present invention aims to overcome the aforementioned drawbacks, and to do so relates to an underbody assembly for a motor vehicle, comprising: - a floor, comprising two half-floors, - a longitudinal central tunnel, extending between said half-floors, - at least one front seat crossmember, fixed to said floor and comprising a first end connected to said tunnel and a second end fixed to a longitudinal side member laterally bordering said floor, - a heel board, mounted behind said at least one front seat cross member, comprising a transverse face extending perpendicularly relative to said floor, said underbody assembly being remarkable in that it comprises a force distribution device comprising at least one oblique rib arranged on said transverse face of said heel board so as to approach said central tunnel.

[0021] Thus, by providing a heel board comprising oblique ribs at its transverse face so as to approach the central tunnel, the oblique ribs are substantially perpendicular to the folds which come from the front seat floor during a lateral impact suffered by the motor vehicle.

[0022] This allows us to reduce the amplitude of the forces perceived by the heel board.

[0023] The localization of the forces is therefore controlled, and bending the board is avoided. heel during a side impact.

[0024] By avoiding deformation of the heel board, the overall level of intrusion of the post into the passenger compartment of the motor vehicle is reduced, thereby increasing the survival space of the occupants and allowing the deployment of occupant protection devices, for example airbags, more effectively.

[0025] Thus, thanks to the present invention, the safety of the motor vehicle is greatly improved without adding an additional reinforcement part, which makes it possible not to impact the mass of the motor vehicle.

[0026] Furthermore, the present invention can be implemented without requiring any additional action at the line edge. Indeed, the oblique ribs can be directly formed during the stamping step of the heel board.

[0027] According to optional characteristics of the base assembly according to the invention: - the angle formed between a median plane of said at least one oblique rib and a horizontal plane containing said floor is between approximately 25° and approximately 60°; - said force distribution device comprises a plurality of oblique ribs arranged on said transverse face of said heel board so as to approach said central tunnel, said oblique ribs being discontinuous and regularly spaced apart; - said force distribution device comprises at least one vertical rib arranged between said at least one oblique rib and said central tunnel. In this way, the propagation of the folds towards the central part of the heel board is blocked by the vertical rib, which further reduces the risk of propagation of the folds towards the central tunnel. The risk of loss of the force path during a lateral impact is further limited; - the distance between said central tunnel and a median plane of said at least one vertical rib is between approximately 20% and approximately 40% of the distance between said longitudinal spar and said central tunnel; - the length of said at least one vertical rib is between approximately 70% and approximately 90% of the height of said transverse face of said heel board; - the length of said at least one oblique rib is between approximately 20% and approximately 50% of the length of said at least one vertical rib; - the thickness of said at least one oblique rib and / or the thickness of said at least one vertical rib is less than approximately 10 mm.

[0028] The invention also relates to a motor vehicle comprising an underbody assembly, remarkable in that said underbody assembly is according to the invention. Brief description of the drawings

[0029] 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:

[0030] [Fig-1] shows an underbody assembly of a motor vehicle according to the invention, seen from above.

[0031] [Fig.2] shows the base assembly in perspective, centered on zone II of [Fig.l].

[0032] [Fig.3] is a sectional view along line III-III of [Fig.2].

[0033] [Fig.4] is a view similar to that of [Fig.2], in which are shown some ribs of the heel board of the invention.

[0034] [Fig.5] shows the path of forces on the heel board of the invention when the motor vehicle is subjected to a side impact. Description of the embodiments

[0035] In the remainder of the description, elements having an identical structure or similar functions are designated by the same reference.

[0036] By convention, longitudinal, vertical and transverse orientations will be adopted, without limitation, indicated by the direct trihedron (L, V, T) designating the longitudinal, vertical and transverse axes of the vehicle.

[0037] In the following, the terms “left”, “right”, “lower” and “upper” are understood in relation to the vehicle.

[0038] 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.

[0039] Reference is made to [Fig.l] showing an underbody assembly 1 of a motor vehicle 3 according to the invention, seen from above.

[0040] The underbody assembly 1 comprises a floor 5, in the lower part of the motor vehicle 3.

[0041] The floor 5 comprises a right half-floor 5d and a left half-floor 5g, separated from each other by a longitudinal central tunnel 7, extending substantially longitudinally relative to the motor vehicle 3 and consisting of a hollow body.

[0042] Laterally, the floor 5 is bordered by a right longitudinal side member 9d and by a left longitudinal side member 9g defining part of the perimeter of the body underbody.

[0043] The underbody assembly 1 further comprises a set of front cross members 11 for the front seat and a set of rear cross members 13 for the front seat.

[0044] The front 11 and rear 13 cross members are fixed to the floor 5, for example by welding.

[0045] The front crossmembers 11 each comprise a first end 15 connected to the central tunnel 7 and a second end 17 fixed to the respective longitudinal spar 9d, 9g.

[0046] Similarly, the rear cross members 13 each comprise a first end 19 connected to the central tunnel 7 and a second end 21 fixed to the respective longitudinal spar 9d, 9g.

[0047] The front 11 and rear 13 cross members are transverse, that is to say that they both extend substantially transversely relative to the underbody assembly 1 and are adapted to support slides (not shown) on which the front seats are mounted.

[0048] According to an alternative embodiment, a single front seat cross member can equip the underbody assembly 1.

[0049] The floor portion 5 on which the seats of the front row rest is called the front seating floor and adjoins a heel board 23 of the underbody assembly 1.

[0050] The heel board 23 is an intermediate transverse piece present between the seats of the front row and the seats of the rear row, on which the heels of the occupants of the rear row rest.

[0051] The heel board 23 extends from the right longitudinal spar 9d to the left longitudinal spar 9g.

[0052] We refer to [Fig.2] showing the base assembly 1 in perspective, centered on zone II of [Fig.l].

[0053] The heel board 23 is mounted behind the rear cross member 13 of the front seat.

[0054] The heel board 23 has a horizontal face 25, extending in a plane (L, T) substantially horizontal merged with the plane containing floor 5.

[0055] Behind its horizontal face 25, the heel board 23 has a transverse face 27, extending perpendicularly relative to the floor 5, and therefore perpendicularly relative to the horizontal face 25 of the heel board 23.

[0056] When the heel board 23 is mounted in the motor vehicle 3, the transverse face 27 of the heel board 23 extends transversely relative to the motor vehicle.

[0057] According to the invention, the underbody assembly 1 comprises a force distribution device designed to distribute the forces undergone by the heel board 23 so as to filter and reduce the amplitude of the forces absorbed by the heel board 23 during a lateral impact.

[0058] In the embodiment illustrated in the figures, the force distribution device comprises a plurality of oblique ribs 29, 31, 33, 35, 37 arranged on the transverse face 27 of the heel board 23 so as to approach the central tunnel 7. The oblique ribs 29, 31, 33, 35, 37 thus extend in the transverse face 27 of the heel board 23 from the bottom to the top of the transverse face 27, from the longitudinal spar 9g (respectively from the longitudinal spar 9d) towards the central tunnel 7.

[0059] In a particular embodiment of the invention, the ribs are said to be oblique when the angle a formed between a median plane Pi of the oblique rib 29, respectively a median plane P2 of the oblique ribs 31, 33, respectively a median plane P3 of the oblique ribs 35, 37, and a horizontal plane PH containing the floor 5, is between approximately 25° and approximately 60°. In the exemplary embodiment illustrated in the figures, the angle a is equal to approximately 45°.

[0060] As will be seen in the remainder of the description, such an arrangement allows the oblique ribs 29, 31, 33, 35 to be substantially perpendicular to the folds which come from the front seat floor when the motor vehicle 3 is subjected to a side impact.

[0061] In the embodiment illustrated in the figures, the oblique ribs 29, 31, 33, 35, 37 are discontinuous and are regularly spaced apart.

[0062] Also, five oblique ribs 29, 31, 33, 35, 37 are shown in the figures. However, the number of oblique ribs may be different. In particular, the force distribution device may comprise a single oblique rib 29, 31, 33, 35, 37 made on the transverse face 27 of the heel board 23. This could therefore make it possible to reduce the amplitude of the forces taken up by the transverse face 27 of the heel board 23.

[0063] In the embodiment illustrated in the figures, the force distribution device comprises a vertical rib 39 arranged between the oblique ribs 29, 31, 33, 35, 37 and the tunnel 7.

[0064] The rib is said to be vertical when the angle [3 formed between a median plane P4 of the vertical rib 39 and the horizontal plane PH containing the floor 5 is equal to approximately 90°.

[0065] As will be seen in the remainder of the description, the presence of the vertical rib 39 makes it possible to block the propagation of the folds towards the central part of the heel board 23 during the impact. Thanks to such an arrangement, the risk of propagation of the folds towards the tunnel 7 is reduced, which could lead to a loss of the force path.

[0066] In the embodiment illustrated in the figures, the force distribution device comprises a single vertical rib 39. However, the number of vertical ribs may be different. In particular, the force distribution device may comprise more vertical ribs 39 made on the transverse face 27 of the heel board 23. Also, the force distribution device may not comprise a vertical rib 39, for example when the force distribution device comprises an oblique rib extending over almost the entire height of the transverse face 27 of the heel board 23.

[0067] Reference is made to [Fig.3] which is a sectional view along line III-III of [Fig.2].

[0068] In one embodiment of the invention, the thickness of at least one of the oblique ribs 29, 31, 33, 35, 37 and / or the thickness of the vertical rib 39 is less than approximately 10mm.

[0069] Reference is made to [Fig.4] which is a view similar to that of [Fig.2], on which certain ribs of the heel board 23 are shown.

[0070] In one embodiment of the invention, the distance Di between the tunnel 7 and the plane P4 of the vertical rib 39 is between approximately 20% and approximately 40% of the distance D2 between the longitudinal spar 9g and the tunnel 7.

[0071] In one embodiment of the invention, the length Li of the vertical rib 39 is between approximately 70% and approximately 90% of the height H of the transverse face 27 of the heel board 23.

[0072] In one embodiment of the invention, the length L2 of one of the oblique ribs 29, 31, 33, 35, 37 is between approximately 20% and approximately 50% of the length Li of the vertical rib 39.

[0073] More particularly, in the embodiment illustrated in the figures, the length L2 of one of the oblique ribs 29, 33, 37 made in the lower part of the transverse face 27 of the heel board 23 is between approximately 20% and approximately 50% of the length Li of the vertical rib 39.

[0074] In one embodiment of the invention, the oblique ribs 29, 33, 37 have the same length L2.

[0075] In one embodiment of the invention, the oblique ribs 29, 33, 37 formed in the lower part of the transverse face 27 of the heel board 23 have the same length L2 while the oblique ribs 31, 35 formed in the upper part of the transverse face 27 of the heel board 23 have a length L3 equal to approximately twice the length L2.

[0076] According to one arrangement, the distance D3 between the median plane Pi of the oblique rib 29 and the median plane P2 of the oblique ribs 31, 33 is approximately equal to the distance Di between the tunnel 7 and the plane P4 of the vertical rib 39.

[0077] Similarly, in one embodiment, the distance D4 between the median plane P2 of the oblique ribs 31, 33 is approximately equal to the distance D3.

[0078] In one embodiment of the invention, the distance D5 between the oblique ribs 31, 33 is approximately equal to the length L2 of one of the oblique ribs 29, 33, 37.

[0079] Similarly, the distance D6 between the oblique ribs 37, 39 is approximately equal to the distance D5.

[0080] Reference is made to [Fig.5] showing the path of forces on the heel board 23 of the invention when the motor vehicle 3 is subjected to a lateral impact.

[0081] When the motor vehicle 3 is subjected to a side impact, a post 41 becomes embedded in the motor vehicle 3 at the front door.

[0082] The spar 9g (or the spar 9d depending on the point of impact of the post) is subjected to bending stress, causing the front cross member (not visible) and the rear cross member 13 of the front seat to be stressed.

[0083] This results in the appearance of folds 43 oriented substantially at 45° on the front seat floor.

[0084] Folding the front seat floor causes the folds 43 to propagate to the heel board 23, as shown by the arrows 45 in [Fig.5].

[0085] The oblique ribs 29, 31, 33, 35, 37, made on the transverse face 27 of the heel board 23 so as to approach the central tunnel 7, are thus substantially perpendicular to the folds 43 which come from the front seat floor, which makes it possible to reduce the amplitude of the forces perceived by the heel board 23, as represented by the arrows 47.

[0086] Thus, thanks to the present invention, the localization of the forces is controlled and bending of the heel board 23 is avoided.

[0087] By avoiding deformation of the heel board 23, the overall level of intrusion of the post 41 into the passenger compartment of the motor vehicle 3 is reduced, thereby increasing the survival space of the occupants. Occupant protection devices, for example airbags, can also be deployed more effectively.

[0088] When the heel board comprises the vertical rib 39, the propagation of the folds represented by the arrows 47 towards the central part of the heel board 23 is blocked by the vertical rib 39, which makes it possible to further reduce the risk of propagation of the folds towards the tunnel 7. The risk of loss of the force path during a lateral impact is further limited.

[0089] Thus, thanks to the present invention, the safety of the motor vehicle 3 is greatly improved without adding an additional reinforcement part, which makes it possible not to impact the mass of the motor vehicle.

[0090] Furthermore, the present invention can be implemented without requiring any additional action at the line edge. Indeed, the oblique ribs 29, 31, 33, 35, 37 and the vertical rib 39 can be directly formed during the stamping step of the heel board 23.

[0091] As goes without saying, the present invention is not limited to the embodiments of this underbody assembly and of this motor vehicle comprising such an 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) for a motor vehicle (3), comprising: - a floor (5), comprising two half-floors (5d, 5g), - a longitudinal central tunnel (7), extending between said half-floors (5d, 5g), - at least one front seat crossmember (11, 13), fixed to said floor (5) and comprising a first end (15) connected to said central tunnel (7) and a second end (17) fixed to a longitudinal side member (9g, 9d) laterally bordering said floor (5), - a heel board (23), mounted behind said at least one front seat crossmember (11, 13), comprising a transverse face (27) extending perpendicularly relative to said floor (5), said underbody assembly (1) being characterized in that it comprises a force distribution device comprising at least one oblique rib (29, 31, 33, 35,37) arranged on said transverse face (27) of said heel board (23) so as to approach said central tunnel (7), said at least one oblique rib (29, 31, 33, 35, 37) extending in said transverse face (27) of said heel board (23) from bottom to top of said transverse face (27), from said longitudinal spar (9g, 9d) towards said central tunnel (7).,

2. Base assembly (1) according to claim 1, characterized in that the angle (a) formed between a median plane (Pb P2, P3) of said at least one oblique rib (29, 31, 33, 35, 37) and a horizontal plane (PH) containing said floor (5) is between approximately 25° and approximately 60°.

3. A base assembly (1) according to one of claims 1 or 2, characterized in that said force distribution device comprises a plurality of oblique ribs (29, 31, 33, 35, 37) arranged on said transverse face (27) of said heel board (23) so as to approach said central tunnel (7), said plurality of oblique ribs (29, 31, 33, 35, 37) extending in said transverse face (27) of said heel board (23) from bottom to top of said transverse face (27), from said longitudinal spar (9g, 9d) towards said central tunnel (7), said oblique ribs (29, 31, 33, 35, 37) being discontinuous and regularly spaced apart.

4. Base assembly (1) according to any one of claims 1 to 3, characterized in that said force distribution device comprises at least one vertical rib (39) arranged between said at least one oblique rib (29, 31, 33, 35, 37) and said central tunnel (7).

5. Underbody assembly (1) according to claim 4, characterized in that the distance (DJ between said central tunnel (7) and a median plane (P4) of said at least one vertical rib (39) is between approximately 20% and approximately 40% of the distance (D2) between said longitudinal spar (9g, 9d) and said central tunnel (7).

6. Base assembly (1) according to one of claims 4 or 5, characterized in that the length (Li) of said at least one vertical rib (39) is between approximately 70% and approximately 90% of the height (H) of said transverse face (27) of said heel board (23).

7. Base assembly (1) according to any one of claims 4 to 6, characterized in that the length (L2) of said at least one oblique rib (29, 31, 33, 35, 37) is between approximately 20% and approximately 50% of the length (LJ) of said at least one vertical rib (39).

8. Base assembly (1) according to any one of claims 4 to 7, characterized in that the thickness (E) of said at least one oblique rib (29, 31, 33, 35, 37) and / or the thickness (E) of said at least one vertical rib (39) is less than approximately 10mm.

9. Motor vehicle (3) comprising an underbody assembly (1), characterized in that said underbody assembly (1) is according to any one of claims 1 to 8.

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