Rear part structure of a vehicle body and a motor vehicle

Abstract

The present invention relates to a structure (1) of a rear part of a motor vehicle body, which has a longitudinal direction and a transverse direction perpendicular to the longitudinal direction. The structure includes two lateral spars (10, 11) extending in the longitudinal direction, one end of each lateral spar being connected to a front transverse structural element (12) and the other end thereof being connected to a rear transverse structural element (13). Each transverse structural element (12, 13) extends in the transverse direction. It is characterized in that the structure includes two auxiliary spars (14, 15) between the two spars (10, 11). The two auxiliary spars extend in the longitudinal direction and are each positioned at a certain distance from the spars (10, 11) in the transverse direction. One end of each auxiliary spar (14, 15) is connected to the front transverse structural element (12) and the other end thereof is connected to the rear transverse structural element (13).

Description

Technical Field

[0001] The present invention relates to a structure of a rear part of a motor vehicle body equipped with a spar and an auxiliary spar. Background Art

[0002] Hybrid vehicles (vehicles called HEV “Hybrid Electric Vehicle” or PHEV “Plug-in Hybrid Electric Vehicle”) include a thermal engine connected to a fuel tank and a traction battery. The battery and the fuel tank are generally located at the level of the rear structure of the vehicle body, in particular close to the rear axle system that supports the rear wheels of the vehicle. This rear structure of the vehicle body generally has two lateral spars that extend along the longitudinal direction of the vehicle and are connected to two transverse members that extend along the transverse direction of the vehicle. Thus, the spars and the transverse members form a frame to which the rear axle system is attached. Both the fuel tank and the battery can be positioned adjacent to the rear axle system, towards the front of the vehicle.

[0003] In the case of a longitudinal rear impact, it is necessary to ensure the integrity of the fuel tank in order to reduce the risk of leakage, and to ensure the integrity of the battery in order to reduce repair costs and the risk of fire caused by the deterioration of the electrical modules inside the battery.

[0004] There are arrangements for absorbing rear impacts. In particular, document FR 3050704 A1 describes a rear structure that includes an energy absorption system that includes two longitudinal absorption portions that are each attached to a spar along the spar and are shorter in length than the spar, and the end of the spar located on the rear side of the vehicle is equipped with an energy absorption box also called a “crash box”. Such an energy absorption system functions for high-speed impacts (80 km / h) and helps to absorb energy after the spar has deformed. Thus, this type of energy absorption system does not allow energy to be absorbed from the moment the spar begins to deform. In addition, the use of the crash box increases the mass and makes the construction of the absorption system more complex. Summary of the Invention

[0005] Therefore, there is a need for a structure of a rear part of a motor vehicle body that improves the absorption of high-speed rear impacts and is simple, inexpensive to produce and does not significantly increase the weight.

[0006] To this end, the present invention relates to a structure of a rear part of a motor vehicle body, which structure has a longitudinal direction and a transverse direction perpendicular to the longitudinal direction. The structure according to the invention comprises two lateral beams extending in the longitudinal direction, one end of each lateral beam being connected to a front transverse structural element and the other end thereof being connected to a rear transverse structural element, each transverse structural element extending in the transverse direction. According to the invention, the structure further comprises two auxiliary beams between the two lateral beams, the two auxiliary beams extending in the longitudinal direction and each being positioned at a distance from the lateral beam in the transverse direction, one end of each auxiliary beam being connected to the front transverse structural element and the other end thereof being connected to the rear transverse structural element.

[0007] In such an arrangement, the auxiliary beams thus have the same length as the lateral beams. The auxiliary beams are also spaced apart from the lateral beams in the transverse direction, in particular by a predetermined distance. In other words, the auxiliary beams do not abut against the lateral beams. The auxiliary beams are also not attached to the lateral beams. In particular, in the transverse direction, each auxiliary beam can be separated from the adjacent lateral beam by a distance smaller than the distance separating this auxiliary beam from the other auxiliary beam.

[0008] It should be noted that the longitudinal direction and the transverse direction of the rear part structure of the vehicle body according to the invention correspond to the longitudinal direction and the transverse direction of the vehicle when this structure is mounted on the vehicle. The front-rear direction corresponds to the front-rear direction of the vehicle in this longitudinal direction.

[0009] Due to the arrangement according to the invention, the energy of a longitudinal rear impact to which the vehicle is subjected is absorbed simultaneously by the lateral beams and the auxiliary beams, the ends of each lateral beam being connected to the same transverse structural element, thus improving the ability of the rear structure to withstand impacts, especially high-speed impacts (for example = 51 km / h, to meet the requirements of the standard NF EN 12767 - October 2011, rear impact of a rigid moving obstacle with a mass of 1100 kg - also known as impact BMR1100).

[0010] Advantageously, each auxiliary beam can be a section. Thus, the auxiliary beams can be created in a simple and inexpensive manner. Each auxiliary beam can in particular have a U-shaped or Ω-shaped open cross-section to obtain better strength. When the rear part structure according to the invention is mounted in the vehicle, the opening of this cross-section can in particular be oriented towards the top of the vehicle.

[0011] Such a section can be made of a metallic material, such as steel (especially stainless steel), aluminium, aluminium alloy or any other suitable metal or metal alloy.

[0012] Generally, the lateral beams can also be sections with a similar open cross-section, which section is in particular made of metal.

[0013] Moreover, generally, the auxiliary spar and possibly the spar can be attached to a structural element that forms a bottom plate on the open side of the cross-section of the auxiliary spar and the spar.

[0014] Advantageously, each spar and auxiliary spar can include at least one attachment member for the rear axle system. Such an attachment member can be a simple hole for attaching the rear axle system by means of threaded connection, riveting, etc. In particular, each auxiliary spar can be positioned at a sufficient distance from the lateral spar in the longitudinal direction so as to attach the rear axle system to the auxiliary spar. This makes it possible to attach the rear axle system to the rear part structure according to the invention without having to provide a specific attachment housing, thus facilitating assembly and reducing the number of components.

[0015] Advantageously, the structure can include means for receiving shock absorber springs on each side in the lateral direction, one end of the receiving means being attached to the spar and the other end being attached to an adjacent auxiliary spar. The receiving means is thus encapsulated between the auxiliary spar and the adjacent spar, which improves the stability of the receiving means by allowing the force exerted by the shock absorber spring to be distributed between the spar and the adjacent auxiliary spar. Preferably, for better stability and simpler attachment, each receiving means can extend in the lateral direction. In particular, each receiving means can have a receiving area for the shock absorber spring, which is located between the spar and the adjacent auxiliary spar.

[0016] Advantageously, the lateral structural element, the spar and the auxiliary spar are made of a metallic material, such as steel (especially stainless steel), aluminium, aluminium alloy or any other suitable metal or metal alloy. The auxiliary spar is then fixed to the lateral structural element by welding.

[0017] The invention also relates to a motor vehicle having a rear part structure of the vehicle body according to the invention.

[0018] Advantageously, the vehicle includes a thermal engine connected to a fuel tank and a traction battery, the traction battery being positioned between the auxiliary spar and the front and rear lateral structural elements, and the fuel tank being positioned along the front lateral structural element on the front side of the vehicle.

[0019] A motor vehicle generally has a rear axle system that includes a transverse member that extends in the lateral direction and connects two arms, each of which supports a wheel. Advantageously, the rear axle system can be attached both to the spar and to the auxiliary spar. This arrangement makes it possible to avoid having to provide additional specific fasteners on the rear part structure.

[0020] Typically, the rear axle system also has shock absorber springs which are connected to the rear body part structure on each side in the lateral direction of the structure. Advantageously, each shock absorber spring can be supported on the receiving means of the rear part structure as described above. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The present invention will now be described with reference to the non - limiting drawings, in which:

[0022] Figure 1 Figure 1 A bottom view of a rear body part structure according to an embodiment of the present invention is shown, to which a rear axle system, a traction battery and a fuel tank are attached.

[0023] Figure 2 Figure 2 Shows Figure 1 a bottom view of the rear part structure shown above.

[0024] Figure 3 Figure 3 A perspective view of an auxiliary wing beam is shown.

[0025] Figure 4 Figure 4 Shows Figure 1 and Figure 2 a bottom perspective view of the details of the rear part structure shown above. DETAILED DESCRIPTION

[0026] In this specification, the terms front, rear, upper and lower refer to the front - to - rear direction of the vehicle when the rear body part structure of the vehicle is mounted on the vehicle. The X - axis, Y - axis and Z - axis respectively correspond to the longitudinal axis (from front to rear), transverse axis and vertical axis of the vehicle when the vehicle is parked on the ground. Thus, the vertical direction corresponds to the direction of gravity.

[0027] Figure 1 A bottom view of a rear part structure 1 of a motor vehicle is shown, to which a rear axle system 2, a traction battery 3 and a fuel tank 4 are attached, the fuel tank being intended to supply a thermal engine (not shown). The traction battery 3 and the fuel tank 4 are arranged in front of the rear axle system 2 in the longitudinal direction X of the vehicle.

[0028] The rear part structure 1 of the motor vehicle includes a left lateral wing beam 10 and a right lateral wing beam 11, each of which extends along the longitudinal direction X of the vehicle. These lateral wing beams 10, 11 are connected to each other by a front transverse structural element 12 and a rear transverse structural element 13 to form a rigid frame. In other words, the front end of each lateral wing beam is connected to the front transverse structural element, and its rear end is connected to the rear transverse structural element 13.

[0029] ​​​​​​​​Typically, the rear transverse structural element 13 may have a closed hollow cross-section. Such an element can contribute to the torsional strength of the rear structural part and limit rolling vibrations. This type of rear transverse structural element is positioned, for example, along the rear opening of the vehicle's trunk.

[0030] Typically, regardless of the embodiment, the rear part structure 1 may also have a rear end transverse member 20, as shown in the example, which is located behind the rear transverse structural element 13 and is intended to receive and absorb low-speed impacts (e.g., less than 10 km / h, to meet the impact protocols specified by Euro NCAP (European New Car Assessment Programme) and RCAR (Research Council for Automobile Repairs)). The rear end transverse member 20 is connected in a conventional manner to the side spars 10, 11, here by connecting elements 20a, 20b, which each extend along the extension of the side spar.

[0031] According to the invention, the rear part structure 1 of a motor vehicle comprises two auxiliary spars 14, 15, which each extend in the longitudinal direction of the vehicle close to the spars 10, 11. Thus, the rear part structure 1 has a left lateral auxiliary spar 14 and a right lateral auxiliary spar 15. These auxiliary spars are positioned at a distance from the side spars in the transverse direction. This distance can be determined by a person skilled in the art depending on the distance between the spars, depending on the position of the rear axle system attachments as described below and / or depending on the technical elements that may be accommodated between the auxiliary spars and / or between a spar and an adjacent auxiliary spar. Advantageously, for a better distribution of impact absorption, each of the auxiliary spars may be positioned at the same distance from the laterally adjacent side spar.

[0032] Furthermore, each auxiliary spar 14, 15 extends between the front transverse structural element 12 and the rear transverse structural element 13 and is connected to the front transverse structural element and the rear transverse structural element. Thus, the front end of each auxiliary spar 14, 15 is connected to the front transverse structural element 12, and its rear end is connected to the rear transverse structural element 13. The auxiliary spars 14, 15 thus have the same length as the spars 10, 11.

[0033] In this example, each auxiliary spar is positioned in the middle of the rear part structure 1 and the side spar in the transverse direction Y. Preferably, each of the auxiliary spars is closer to the side spar in the transverse direction Y than to the other auxiliary spar, in particular than to the center of the rear part structure 1. This allows for a sufficiently large space to be left between the auxiliary spars 14, 15 to accommodate one or more technical elements, such as the fuel tank 4 in the example described.

[0034] In the embodiment described, each auxiliary spar 14, 15 is a metal section having a U-shaped or Ω-shaped open cross-section (in this case an Ω-shaped open cross-section), as inFigure 3 can be seen more clearly. It should be noted that the opening of this cross-section points towards the top of the vehicle. In this example, this opening is closed by a structural element forming the floor panel 5, which extends over the spar and the auxiliary spar and is shown in Figure 4 as shown.

[0035] Advantageously, the spars 10, 11 are also metal sections, having an open cross-section similar to, for example, the open cross-section of the auxiliary spars 14, 15, and are also closed by the structural element forming the floor panel 5.

[0036] In this example, each spar 10, 11 and each auxiliary spar 14, 15 also has at least one attachment member for the rear axle system. Here, each spar 10, 11 has two attachment members 101, 102, 111, 112, and each auxiliary spar 14, 15 has one attachment member, namely 141 and 151 respectively. These attachment members 101, 102, 111, 112, 141, 145 are in this case simple apertures through which screws, rivets, etc. can pass. Of course, the present invention is not limited by the number of attachment parts provided on the spars and auxiliary spars for attaching the rear axle system.

[0037] In the example shown, the rear part structure 1 also has means 16, 17 for receiving the shock absorber springs on each side. One end of each of the receiving means 16, 17 is attached to the spar, and the other end is attached to the adjacent auxiliary spar. This arrangement of the receiving means 16, 17 allows them to participate in maintaining the geometry of the auxiliary spar. In addition, the forces borne by each of the receiving means 16, 17 are distributed between the spar to which these means are attached and the adjacent auxiliary spar. These receiving means 16, 17 are here in the form of sections having an Ω-shaped open cross-section, the opening of which also points towards the top of the vehicle (and can also be closed by the structural element forming the floor panel 5). The bottom of each section 16, 17 has areas 161, 171 ( Figure 4 ) for supporting the shock absorber springs. These areas 161, 171 extend here in the same horizontal plane as the surfaces of the spar and the auxiliary spar.

[0038] Advantageously, the transverse structural elements, the spars and the auxiliary spars of the rear part structure 1 are made of metal material, and so are the receiving means 16, 17. These different elements can thus be joined to each other by welding, which makes it possible to simplify the production of the rear part structure 1 according to the present invention.

[0039] As required, it should be noted that the auxiliary spars 14, 15 may extend at one or each end thereof with section segments of the same shape. This makes it possible to use mass-produced auxiliary spars of a fixed length to produce rear part structures 1 of different lengths, the length of each auxiliary spar being adapted to the length of the structure 1 by adding one or more section segments of a suitable length. In this example, each of the auxiliary spars 14, 15 extends with a section segment on its rear end side. Figure 3 A section segment 142 for the auxiliary spar 14 is shown in Figure 3 . It should be noted that the section segment 142 can also be used to attach the auxiliary spar to the rear transverse structural element 13.

[0040] As can be seen from Figure 1 the rear part structure 1 receives the rear axle system 2 for attachment purposes. The rear axle system has a transverse member 21 that extends in the transverse direction and connects two arms 22, 23, each of which supports a wheel 24, 25. The shock absorber springs 26, 27 extend between the rear axle system and the rear part structure on each side of the rear axle system in the transverse direction (only the lower receiving area of the shock absorber spring is visible in Figure 1 .

[0041] The arms 22, 23 of the rear axle system 2 are attached to the auxiliary spars and the main spars by attachment members of the auxiliary spars 14, 15 and the main spars 10, 11. The rear axle system 2 is thus attached to the structure 1 only via the main spars and the auxiliary spars, such that no separate specific attachment means need be provided to attach the rear axle system to the structure.

[0042] Each shock absorber spring is also supported on receiving devices 16, 17 of the rear part structure.

[0043] In the event of a rear impact, the rear end transverse member 20 will deform first. If the rear impact speed is low (e.g., <10 km / h), only the rear end transverse member deforms and must be replaced for repair. If the rear impact speed is high (e.g., =51 km / h), the rear end transverse member continues to deform until the rear end transverse member presses against the rear transverse structural element 13. Thus, the main spars 10, 11 and the auxiliary spars 14, 15 deform simultaneously and absorb the impact energy. For repair, it will then be necessary to replace each of the elements deformed by the impact.

[0044] Of course, the present invention is not limited to the described embodiments. In particular, the rear transverse structural element may form the rear end transverse member, although this is less advantageous for limiting repair costs. Then, starting from a low-speed impact, the deformation of the main spars and the auxiliary spars occurs.

Claims

1. A rear body part structure (1) of a motor vehicle, the rear body part structure having a longitudinal direction and a transverse direction perpendicular to the longitudinal direction, the rear body part structure comprising two lateral side members (10, 11) extending along the longitudinal direction, one end of each lateral side member being connected to a front transverse structural element (12) and the other end thereof being connected to a rear transverse structural element (13), each transverse structural element (12, 13) extending along the transverse direction, characterized in that, The rear part structure of the vehicle body includes two auxiliary wing beams (14, 15) between the two lateral wing beams (10, 11). These two auxiliary wing beams extend along the longitudinal direction and are each positioned at a certain distance from the lateral wing beams (10, 11) in the transverse direction. One end of each auxiliary wing beam (14, 15) is connected to the front transverse structural element (12), and the other end thereof is connected to the rear transverse structural element (13). The rear part structure of the vehicle body has receiving means (16, 17) for receiving shock absorber springs on each side in the transverse direction. One end of the receiving means is attached to the lateral wing beams (10, 11), and the other end thereof is attached to the adjacent auxiliary wing beam (14, 15).

2. The rear body part structure (1) according to claim 1, characterized in that, Each auxiliary wing beam (14, 15) is a section.

3. The rear body part structure (1) according to claim 2, characterized in that, Each auxiliary wing beam (14, 15) is a section having a U-shaped or Ω-shaped open cross-section.

4. The structure (1) of the rear part of the vehicle body according to any one of claims 1 to 3, characterized in that Each lateral wing beam (10, 11) and each auxiliary wing beam (14, 15) have at least one attachment member (101, 102, 111, 112, 141, 151) for the rear axle system.

5. The rear body part structure (1) according to claim 1, characterized in that, Each receiving means (16, 17) extends in the transverse direction.

6. The structure (1) of the rear part of the vehicle body according to any one of claims 1 to 3, characterized in that, These transverse structural elements (12, 13), these lateral wing beams (10, 11) and these auxiliary wing beams (14, 15) are made of a metallic material, and are characterized in that these lateral wing beams and these auxiliary wing beams are fixed to these transverse structural elements by welding.

7. A motor vehicle having a rear part structure (1) of the vehicle body according to any one of claims 1 to 6.

8. The motor vehicle according to claim 7, comprising a thermal engine connected to a fuel tank (4) and a traction battery (3), characterized in that, The traction battery is positioned between these auxiliary wing beams (14, 15) and the front and rear transverse structural elements, and the fuel tank (4) is positioned along the front transverse structural element on the front side of the vehicle.

9. The motor vehicle according to claim 7 or 8, comprising a vehicle rear axle system (2), said vehicle rear axle system having a transverse member (21) and shock-absorber springs (26, 27), said transverse member extending in said transverse direction and connecting two arms (22, 23), each of said two arms supporting a wheel (24, 25), said shock-absorber springs being connected to a rear body sub-structure, characterized in that, The rear axle system is attached to these auxiliary wing beams (14, 15) and these lateral wing beams (10, 11).

10. The motor vehicle according to claim 9, characterized in that, Each shock absorber spring (26, 27) is supported on the receiving means (16, 17) of the rear part structure (1) of the vehicle body.

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