Vehicle floor structure equipped with side impact absorbers

Abstract

The invention relates to a vehicle floor structure (10) formed by a front part (12) comprising a cab chassis (120) and by a rear part (14) comprising two longitudinal members (16) and a plurality of crossmembers (18) connecting the longitudinal members, characterized in that each longitudinal member (16) is equipped with a hollow side impact absorber (20) of omega-shaped cross section fastened to the longitudinal member (16) on the opposite side to the crossmembers (18) and extending from the cab chassis over a portion of the length of the rear part, the impact absorber (20) having a central part of U-shaped cross section secured to two flanges fastened to a vertical longitudinal wall of the longitudinal member.

Description

[0001] Title of the invention: Vehicle floor structure equipped with side impact absorbers

[0002] The invention relates to a vehicle floor structure equipped with side impact absorbers, in particular to protect an energy storage module or a sensitive element from side impacts.

[0003] For several years, the impact of vehicles on environmental conditions has been a central concern for car manufacturers and their customers. In particular, electric vehicles, whether for private or commercial use, are now emerging as a necessity to meet increasingly stringent requirements for reducing polluting emissions.

[0004] Some utility vehicles have a floor structure formed by a front section comprising a cab chassis and a rear section comprising two side members and a plurality of cross members connecting the side members. The rear section is intended to be fitted in the factory, or by bodywork converters, with a structure adapted to the customer's needs. This structure rests on the side members and cross members of the rear section while being fixed to the latter. The structure can be a closed cell, refrigerated or not, a drop-side body or a simple platform.

[0005] When a utility vehicle of this type, also called a chassis cab type vehicle, includes an electric traction battery, the chassis must ensure protection of the battery, particularly against side impacts, regardless of the structure fitted to the rear part of the chassis cab. This protection is essential to keep the battery attached to the vehicle in the event of a side impact and thus avoid damage to it as well as the disadvantages associated with damage, namely environmental risks linked to chemical leaks into the environment, fire risks linked to significant degradation of the battery and the costs of replacing and repairing the battery.

[0006] Document EP2729348B1 describes a vehicle floor structure comprising two main side members connected by cross members between which energy storage modules are arranged. This structure is integrated into the vehicle. The cross members comprise deformation zones with defined behavior. Two secondary side members are also provided, located laterally outside the main side members and connected by two upper cross members extending above the main and secondary side members. These upper cross members are secured to a horizontal upper face of the side members and may or may not be fixed to the main side members. The upper cross members also have deformation zones located transversely between the main and secondary side members. Due to this arrangement of the upper cross members, the latter may be detached from the side members in the event of a side impact, which is not desirable.In one embodiment, additional deformation zones located between the main and secondary side members extend transversely in the same plane as these side members, but are not in alignment with the cross members. While they allow energy to be absorbed, these additional deformation zones are nevertheless likely to cause deformation of the main side members and degradation of the energy storage modules, which is not desirable. The structure described in this document also has the disadvantage of being relatively complex to implement and specific: it cannot be adapted to an existing floor structure of a vehicle.

[0007] There is therefore a need for a vehicle floor structure that provides effective protection for a battery or sensitive element, in particular limiting the risks of the battery or sensitive element becoming detached, and that is simple to produce. There is also a need to easily modify an existing vehicle floor structure and add side protection.

[0008] To this end, the invention relates to a vehicle floor structure formed of a front part comprising a cab chassis and a rear part comprising two side members and a plurality of cross members connecting the side members, characterized in that each side member is equipped with a hollow lateral shock absorber of omega-shaped cross section fixed to the side member on the side opposite the cross members and extending from the cab chassis over a portion of the length of the rear part, the shock absorber having a central part of U-shaped cross section secured to two wings fixed to a vertical longitudinal wall of the side member.

[0009] This arrangement provides effective and simple protection for the side members against side impacts. Existing floor structures can also be easily reinforced laterally without the need for structural modifications.

[0010] Advantageously, the central portion of each side impact absorber may comprise side walls connected by a bottom wall and the side walls may be pierced with a plurality of holes. This allows the force level of the impact absorber to be adjusted to the desired level.

[0011] Advantageously, each side member may be formed from a first part of omega-shaped cross-section and a second part assembled to the first part and closing it, and the cross-section of each side impact absorber may be identical to the cross-section of the first side member part. The same tooling may then be used to produce both the side members and the side impact absorbers, which makes it possible to reduce the manufacturing cost of the floor structure.

[0012] Advantageously, at least one reinforcing element of U-shaped cross-section may be attached to the central portion of each side impact absorber, each reinforcing element being fitted inside or outside the central portion and extending over at least part of the length of the side impact absorber to which it is secured. This makes it possible to reinforce the structure of a shock absorber and / or to adjust its capacity to absorb the energy of an impact.

[0013] The reinforcing element may in particular define with the central part of the side impact absorber a cavity in a transverse direction of the floor structure. When the reinforcing element is external to the side impact absorber, it is understood that it is thus possible to adjust the dimension of the impact absorber in a transverse direction (by adjusting the dimension of the cavity in this direction by choosing a reinforcing element of appropriate dimensions) and thus to adjust the quantity of energy that can be absorbed by the side impact absorber.

[0014] Generally, each side impact absorber can be attached to the side member by screwing or welding, preferably by screwing.

[0015] In general, each side impact absorber may be made of aluminum or steel, preferably aluminum. Aluminum, and in particular extruded aluminum, will preferably be used to reduce weight compared to a steel solution and to reduce the cost of tooling investments (tooling for an aluminum part, in particular extruded aluminum, is less expensive than tooling for profiling a steel part). The floor structure according to the invention may also comprise a support structure for at least one energy storage module fixed to the floor structure, under the latter. The support structure then extends between the side members and the cross members of the rear part over a portion of its length. In this case, the side impact absorbers extend over the entire length of this portion of the rear part.

[0016] The invention also relates to a motor vehicle comprising a floor structure according to the invention. The invention is particularly suitable for electric or hybrid vehicles of the utility type.

[0017] Other features and advantages of the invention will emerge from reading the description given below of several particular embodiments of the invention, given for informational purposes but not as a limitation, with reference to the appended drawings in which:

[0018] [Fig. 1] Figure 1 is a perspective view of a vehicle floor structure according to one embodiment of the invention.

[0019] [Fig. 2] Figure 2 is an enlarged view of a portion of Figure 1.

[0020] [Fig. 3] Figure 3 shows a perspective view of a side impact absorber according to another embodiment of the invention.

[0021] [Fig. 4] Figure 4 shows a perspective view of a side impact absorber according to yet another embodiment of the invention.

[0022] [Fig. 5] Figure 5 represents a cross-section of Figure 1 taken along a sleeper.

[0023] In the present description, the terms front, rear, upper, lower, refer to the front and rear directions of the vehicle, when the floor structure according to the invention is mounted on the vehicle. The axes X, Y, Z, correspond respectively to the longitudinal (front to back), transverse (oriented towards the right of the vehicle) and vertical axis of the vehicle (and consequently of the floor structure), the latter vehicle resting on horizontal ground. The vertical direction thus corresponds to the direction of gravity.

[0024] Figure 1 shows a vehicle floor structure 10 formed of a front part 12 comprising a cab chassis 120 and a rear part 14 comprising two side members 16 and a plurality of cross members 18 connecting the side members 16. The side members 16 of the rear part 14 are typically secured to a base 121 of the cab chassis 120.

[0025] Usually, for greater rigidity, the side members 16 and the cross members 18, typically made of steel, are hollow elongated pieces, preferably with a closed cross section, for example with a rectangular or parallelepiped section. These elongated pieces can be formed in two parts assembled to each other and defining an internal cavity extending in their longitudinal direction. The internal cavity of the side members thus extends in the longitudinal direction of the floor structure 10 while the internal cavity of the cross members extends in the transverse direction of the floor structure 10.

[0026] In the examples shown, each spar 16 is formed of a first part 160 of omega-shaped cross-section and a second part 170 assembled to the first part and closing it. The first part 160 comprises a central part 161 of U-shaped cross-section formed of two side walls 162, 163 connected by a bottom wall 164, this central part 161 being integral with two wings 17 which are fixed to the second part 170, generally a flat plate, as visible in FIG. 2. The side walls 162, 163 thus extend vertically in the longitudinal direction of the floor structure 10. Each spar 16 thus extends vertically over a height LH and extends transversely over a length LL (see FIG. 2).

[0027] According to the invention, each side member 16 is equipped with a hollow lateral shock absorber 20 which will make it possible to absorb the transverse shocks suffered by the floor structure 10.

[0028] For this purpose, each side impact absorber 20 has an omega-shaped cross-section and is fixed to the side member 16 on the side opposite the cross members. Furthermore, each side impact absorber 20 extends from the cab chassis 120 over a portion of the length of the rear part 12. In particular, the side impact absorber 20 has a central part 21 of U-shaped cross-section secured to two wings 22 fixed to the vertical longitudinal wall 162 of the side member. The attachment of the impact absorber 20 to the side member can be carried out by welding, for example by spot welding or the like, or by screwing. The impact absorber 20 can also be made of steel or aluminum.

[0029] The central portion 21 of U-shaped cross-section of the shock absorber 20 is here formed of two side walls 210, 211 connected by a bottom wall 212. In general, the different walls of the shock absorber 20 are typically oriented at right angles to each other, as shown in the figures. The invention is however not limited to this embodiment and a different orientation of the walls relative to each other could be envisaged, provided that the wings 22 extend in the same plane for their attachment to the wall 162 of the side member and that the shock absorber has a cross-section whose shape is similar to an omega (Q).

[0030] The side impact absorber 20 thus defines a longitudinal cavity 23 with the side member 16 which will allow absorption of side impacts.

[0031] The side impact absorber 20 has in particular a dimension L measured in the transverse direction and a dimension H measured vertically. By adjusting the length of the dimension L, it is possible to adjust the amount of energy that the impact absorber will be able to absorb during an impact.

[0032] In order to adjust the resistance to force of the shock absorber 20, its side walls 210, 211 may be pierced with holes 24, as shown in Figure 2. The dimensions and number of holes 24 may be chosen according to the desired resistance to force.

[0033] To simplify the production of the floor structure 10, each side impact absorber 20 may have a cross-section identical to the cross-section of the first part 161 of a side member. The dimensions LH and LL of the side member 16 are then identical to the dimensions L and H respectively of a shock absorber 20 (see FIG. 2). Each side member 16 and shock absorber 20 may thus be produced using the same tooling, the shock absorber 20 being rotated 90° relative to the side member in use, as seen in FIG. 2.

[0034] As shown in Figures 3 and 4, each side impact absorber 20 may further be equipped with one or more reinforcing elements 30, 30' of U-shaped cross-section, which is fixed to the central portion 161 of a side impact absorber. In particular, as shown in Figures 3 and 4, the reinforcing element 30 is fitted outside the central portion 161 (see Figure 3) or the reinforcing element 30' is fitted inside the central portion 161 (Figure 4). In all cases, the reinforcing element 30, 30' extends over at least part of the length of the side impact absorber to which it is secured, preferably over its entire length (along the longitudinal direction). It will thus be possible to provide one or more reinforcement elements 30, 30' for each side member, or a single reinforcement element 30, 30'.Optionally, a shock absorber may comprise at least one outer reinforcing element 30 and at least one inner reinforcing element 30'.

[0035] Each reinforcing element 30, 30' is formed of two side walls 31a, 31b; 31'a, 31'b respectively, connected to each other by a bottom wall 31c, 31'c respectively, as shown in Figures 3 and 4. Due to the interlocking, the side walls 31a, 31b; 31'a, 31'b are thus supported partially (over a length £ for example - see Figure 3) or entirely (Figure 4) on the side walls 210, 211 of the central part of the side impact absorber.

[0036] When the reinforcing element 30 is located outside the shock absorber 20, it can in particular define a cavity 32 with the latter as shown in FIG. 3. This cavity 32 makes it possible to lengthen the shock absorber transversely, its length L' being greater than the length L of the shock absorber alone. This makes it possible to absorb more energy.

[0037] When the reinforcing element 30' is located outside the shock absorber 20, it may or may not define a cavity with the latter. In the example shown in Figure 4, the reinforcing element 30' simply bears against the bottom wall of the shock absorber to reinforce it structurally. However, it could be moved apart transversely to create a cavity with the bottom of the shock absorber.

[0038] Whatever the embodiment, the reinforcing element 30, 30', which may be made of steel or aluminum, is advantageously fixed by welding to the shock absorber 20. In particular, the reinforcing element 30, 30' may be made so that its side walls 31a, 31b; 31'a, 31'b bear on the side walls 210, 211 of the central part of the side shock absorber over a sufficient length to achieve the fixing by welding. If the side walls of the shock absorber are pierced with holes, the reinforcing element(s) may then advantageously be arranged so as not to close the holes. It will be noted that the different embodiments previously described (presence or absence of holes 24 and reinforcing elements 30, 30') may be combined according to the desired strength of the shock absorber.

[0039] The floor structure 10 according to the invention thus makes it possible to protect one or more energy storage modules 40, such as electric battery modules, typically supported by a support structure 50 which is fixed to the floor structure, under the latter, generally to the side members 16. As visible in Figures 1 and 5, the support structure 50 extends between the side members 16 and the cross members 18 of the rear part over a portion of the length thereof. The support structure 50 also extends partly under the underbody 121 of the cabin chassis 120. As shown in these figures, the two side impact absorbers 20 extend over the entire length of the portion of the length of the rear part over which the support structure 50 extends.Thus, in the event of a side impact, the side impact absorber 20 can absorb the energy of the impact, limit the deformation of the side member of the floor structure to which it is attached, and thus limit the risk of breakage of the attachments of the support structure 50 to this side member.

[0040] The side impact absorbers 20 also make it possible to choose a support structure 50 designed to participate in the protection of the energy storage modules 40 or not. It will be noted that this type of side impact absorber 20 can also equip a thermal vehicle when a sensitive element (tank or other) that one wishes to protect from side impacts is fixed to the floor structure near the cab chassis. The invention can thus be applied to a thermal motor vehicle as well as to an electric motor vehicle, although use for an electric or hybrid motor vehicle is preferred.

Claims

Claims

1. Vehicle floor structure (10) formed of a front part (12) comprising a cab frame (120) and a rear part (14) comprising two side members (16) and a plurality of cross members (18) connecting the side members, characterized in that each side member (16) is equipped with a hollow lateral shock absorber (20) of omega-shaped cross section fixed to the side member (16) on the side opposite the cross members (18) and extending from the cab frame over a portion of the length of the rear part, the shock absorber (20) having a central part (21) of U-shaped cross section secured to two wings (22) fixed to a vertical longitudinal wall (162) of the side member.

2. Floor structure (10) according to claim 1, characterized in that the central part (21) of each side impact absorber comprises side walls (210, 211) connected by a bottom wall (212) and in that the side walls (210, 211) are pierced with a plurality of holes (24).

3. Floor structure (10) according to claim 1 or 2, characterized in that each side member (16) is formed of a first part (161) of omega-shaped cross-section and a second part (170) assembled to the first part and closing it, and in that the cross-section of each side impact absorber is identical to the cross-section of the first side member part (161).

4. Floor structure (10) according to any one of claims 1 to 3, characterized in that at least one reinforcing element (30, 30') of U-shaped cross-section is fixed to the central part (21) of each side impact absorber (20), each reinforcing element (30, 30') being fitted inside or outside the central part (21) and extending over at least part of the length of the side impact absorber to which it is secured.

5. Floor structure (10) according to claim 4, characterized in that the reinforcing element (30, 30') defines with the central part (21) of the lateral impact absorber a cavity (32) in a transverse direction of the floor structure.

6. Floor structure (10) according to any one of claims 1 to 5, characterized in that each side impact absorber (20) is fixed to the side member (16) by screwing or welding.

7. Floor structure (10) according to any one of claims 1 to 6, characterized in that each side impact absorber (20) is made of aluminum or steel, preferably aluminum.

8. Floor structure (10) according to any one of claims 1 to 7, characterized in that it comprises a support structure (50) of at least one energy storage module (40) fixed to the floor structure (10), under the latter, the support structure (50) extending between the side members (16) and the cross members (18) of the rear part (14) over a portion of the length thereof, and in that the side impact absorbers (20) extend over the entire length of this portion of the length of the rear part.

9. Motor vehicle characterized in that it comprises a floor structure (10) according to any one of claims 1 to 8.

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