MOTOR VEHICLE STRUCTURE

Description

[0001] The invention relates to a chassis side member of a motor vehicle structure comprising a first bent profile and a second bent profile adjacent to the first profile.

[0002] The published patent document WO 2012 / 0168611 A1 describes a motor vehicle structure, and in particular a vehicle chassis side member. This side member is subjected to stress during frontal or side impacts and thus contributes to the vehicle's passive safety. It also provides a support for attaching other chassis or body parts. The mechanical strength of such side members can be improved, for example, by increasing the thickness of the sheet metal used. This solution directly results in an increase in the vehicle's weight. Using thicker sheet metal also necessitates modifications to the tools and / or assembly methods. This is undesirable in an assembly line that must be able to flexibly handle different vehicle types with minimal tooling changes. Another way to increase mechanical strength is by adding localized reinforcements, but these impair the curing properties of the cataphoresis coating.

[0003] Document JP 2009 173110 A describes a rocker panel made up of two assembled sides, the inner side of which has a sheet metal thickness reinforcement on the assembly rebates to suppress rocker panel deformations during collisions.

[0004] The invention therefore aims to provide a motor vehicle structure that meets mechanical strength criteria, can be assembled with existing tools and does not increase the vehicle weight more than strictly necessary.

[0005] The invention relates to a chassis side member according to claim 1. "Folded" means a profile shaped by plastic deformation of the type folding, stamping or profiling.

[0006] Therefore, the tools used to assemble automotive structures that do not exhibit variations in side thickness can also be used to assemble this new structure. This is particularly true for performing spot welding at the joint rebates. Furthermore, the extent of the excess material required to ensure the structure's mechanical strength is limited to the necessary areas.

[0007] Advantageously, the junction rebate(s) include an assembly of the profile edges by electric spot welding.

[0008] According to an advantageous embodiment, the first thickness is greater than 0.8 mm and / or less than 1.1 mm.

[0009] Advantageously, the second thickness is greater than 2 mm and / or less than 2.8 mm. This range of values ​​allows, for example, the impact resistance of a PHEV (Plug-In Hybrid Electric Vehicle).

[0010] According to an advantageous embodiment, the second layer is greater than at least twice the first layer.

[0011] According to an advantageous embodiment, each of the first and second profiles is a hollow section profile formed by the second thickness sheet(s), and with two opposing edges laterally forming two of the junction rebates of the profiles, said edges being formed by two of the first thickness sheets.

[0012] According to an advantageous embodiment, the first profile is an inner side member of the rocker panel and the second profile is an outer side member of said rocker panel.

[0013] According to an advantageous embodiment, the hollow section of the second profile is U-shaped.

[0014] According to an advantageous embodiment, the metal sheets are joined end to end by laser welding.

[0015] Other features and advantages of the present invention will be better understood with the aid of the description and drawings, among which are: There figure 1 describes the two profiles before their assembly; The figure 2 the assembled profiles.

[0016] There figure 1 represents a section of a first profile (1) and a second profile (2) intended to be assembled to form part of the structure of a motor vehicle.

[0017] Bent profiles are to be understood in a broad sense, meaning they are obtained by bending, stamping, or profiling a sheet of metal (profile 1 in the illustrated embodiment) or several sheets of metal previously joined together (profile 2). The technique used to join the sheets end-to-end before shaping can be laser welding. Such sheets are commercially available, notably from ArcelorMittal®. They are commonly referred to as butted or laser-welded blanks, combining several grades and / or thicknesses. Another technique that can be used to join the sheets before plastic deformation is roller butting.

[0018] In the illustrated example, the profiles are chassis side members. The representation of figures 1 et 2 is done in the plane orthogonal to the longitudinal direction of the stringers.

[0019] In the illustrated embodiment, each profile has two edges (1.1, 1.2, 2.1, 2.2) which are intended to face each other (see figure 2 The edges are joined by electric welding, preferably by spot welding. The vehicle structure may naturally comprise more than two profiles, joined together at at least one of their respective edges.

[0020] Between the two edges is a concave intermediate zone, which may be generally U-shaped and / or may have multiple folds, curves, or angles. The shape of the profiles is derived from the vehicle's structural design, particularly for sealing or sound insulation requirements. Very schematically, they are represented in figure 2 the bottom of the vehicle door (3) and the seals (4) between the door and the bottom of the body.

[0021] At least one of the profiles has a non-constant thickness. In other words, at least one of the sheets (2.3) from which it is formed is thicker than the other sheets (2.1, 2.2). The thicker sheet is located further from the edges. This allows the edges to be joined using the same techniques and tools as for profiles of constant thickness. The area of ​​greater thickness allows the profile to withstand the mechanical stresses to which it may be subjected.

[0022] In this example, it is the profile (2) located on the outer side of the vehicle that exhibits this variation in thickness. Alternatively, or in combination, the inner profile (1) may also exhibit a variation in thickness. When the vehicle structure comprises more than two profiles, any other profile may also exhibit this characteristic.

[0023] In a non-limiting example, the thickness values ​​can range from 0.8 to 1.1 mm for edges or thin areas (1.1, 1.2, 1.3, 2.1, 2.2) and from 2 to 2.8 mm for thicker areas (1.3). The ratio between the maximum and minimum thicknesses is approximately 2. It is understood that a person skilled in the art would be able to adapt these values ​​and the maximum / minimum thickness ratio according to standard sizing criteria.

Claims

1. Chassis side member of a motor vehicle structure, comprising: - first folded section (1); - a second folded section (2) adjacent to the first section (1) and having two edges (2.1, 2.2) each fixed to a different edge (1.1, 1.2) of the first section (1) so as to form a joining rabbet; the second section (2) being constituted by a blank comprising at least three metal sheets (2.1, 2.2, 2.3) joined end to end, at least two of said sheets (2.1, 2.2) each comprising one of the edges forming the rebate and having a first thickness, and at least one other of said sheets (2. 3) being at a distance from said edges (2.1, 2.2) forming the rebate, characterised in that the other of said sheets (2.3) at a distance from said edges of the two of said sheets has a second thickness greater than the first thickness, the sheet of greater thickness being at a distance from the edges.

2. Chassis side member of a motor vehicle structure, according to claim 1, characterised in that the first thickness is greater than 0.8 mm and / or less than 1.1 mm.

3. Chassis side member of a motor vehicle structure, according to one of claims 1 and 2, characterised in that the second thickness is greater than 2 mm and / or less than 2.8 mm.

4. Chassis side member of a motor vehicle structure, according to one of claims 1 to 3, characterised in that the second thickness is greater than at least twice the first thickness.

5. Chassis side member of a motor vehicle structure, according to one of Claims 1 to 4, characterised in that each of the first and second sections (1, 2) is a section of hollow section formed by the sheet or sheets of second thickness (2.3), and with two opposite edges (1.1, 1.2, 2.1, 2.2) laterally forming two of the junction rabbets of the sections, said edges being formed by two of the sheets of first thickness.

6. A chassis spar of a motor vehicle structure, according to claim 5, characterised in that the first section is an inner side spar of the lower body and the second section is an outer side spar of said lower body.

7. Chassis side member of a motor vehicle structure, according to one of claims 5 and 6, characterised in that the hollow section of the second section is U-shaped.

8. Chassis side member of a motor vehicle structure, according to one of claims 1 to 7, characterised in that the metal sheets (1.1, 1.2, 1.3, 2.1, 2.2, 2.3) are joined end to end by laser welding or by splicing before they are shaped.