Rockers for vehicles and vehicles comprising such rockers

1. A vehicle comprising a rocker of a central underbody, the vehicle and the rocker comprising

a main elongation axis, a width axis and a height axis, a lower portion and an upper portion, the rocker further comprising:

a central core comprising a length extending along the main elongation axis and a height extending along the height axis;

two hollow units extending along the length of the central core and arranged on one side and the other of the central core such that one of the units is closer to an outside of the vehicle than the other unit, and such that a cross-section of the units, in the main elongation axis, forms a closed polygon on the length of the central core;

two flanges projecting from the lower portion and upper portion of the rocker; wherein

the units comprise a height extending along the height axis, and the sum of the height of the two units is not more than the height of the central core that separates the two flanges;

the rocker is adapted such that, when it is subjected to bending created by application of a force extending along the width axis or the height axis, it comprises a neutral elongation axis situated between the two units and which delimits a first area of the rocker that is subjected to tension and a second area of the rocker that is subjected to compression, and at least 80% of one of the units is situated in the first area and at least 80% of the other unit is situated in the second area;

the unit that is arranged closest to an outside of the vehicle is situated closer to an upper portion of the vehicle than the other unit.

2. The vehicle according to claim 1 , wherein each unit comprises a wall that is transverse to the length of the central core, the wall being inclined at an angle comprised between 90° and 105° relative to the height axis.

3. The vehicle according to claim 1 , wherein each unit is formed by assembling a reinforcement with the central core.

4. The vehicle according to claim 3 , wherein the reinforcements assembled with the central core have a higher elastic limit than that of the central core.

5. The vehicle according to claim 1 , wherein the rocker includes two lateral reinforcements so as to form the central core, the two units and the flanges.

6. The vehicle according to claim 1 , wherein the central core comprises reinforcements such that it is more rigid.

7. The vehicle according to claim 6 , wherein the central core comprises a lateral rib situated opposite each of the units along the width axis, the lateral rib being extending so as to project opposite the unit.

8. The vehicle according to claim 1 , wherein the whole of one unit is situated in the first area, and the whole of the other unit is situated in the second area.

9. The vehicle according to claim 1 , wherein the units are identical in shape.

10. The vehicle according to claim 1 , wherein the units are different in shape.

11. The vehicle according to claim 1 , wherein the units comprise steps.

12. A rocker of a vehicle; the rocker comprising:

a central core comprising a length extending according to the main elongation axis and a height extending along the height axis;

two hollow units extending along the length of the central core and arranged on one side and the other of the central core, such that one unit is closer to an outside of the vehicle than the other unit, and a cross-section of the units, in the main elongation axis, forms a closed polygon on the length of the central core;

two flanges projecting from the lower portion and the upper portion of the rocker.