US 12,409,889 B2
Rear structure for an electric vehicle
Alexandre Sotty, Compiègne (FR); Elie Gibeau, Pont-Sainte-Maxence (FR); Nicolas Schneider, Saint Martin Longueau (FR); and Yves Drouadaine, Pontoise (FR)
Assigned to ArcelorMittal, Luxembourg (LU)
Appl. No. 17/640,058
Filed by ArcelorMittal, Luxembourg (LU)
PCT Filed Jul. 31, 2020, PCT No. PCT/IB2020/057274
§ 371(c)(1), (2) Date Mar. 3, 2022,
PCT Pub. No. WO2021/044234, PCT Pub. Date Mar. 11, 2021.
Prior Publication US 2022/0332371 A1, Oct. 20, 2022
Int. Cl. B62D 21/15 (2006.01); B62D 29/00 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/22 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/38 (2006.01)
CPC B62D 21/152 (2013.01) [B62D 29/007 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/06 (2013.01); C22C 38/22 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A rear structure for an electric vehicle, the rear structure comprising:
at least two rear rails, each comprising at least:
a rear portion extending in the longitudinal direction at a same elevation as a rear bumper assembly and attached at a rear end to the rear bumper assembly;
a front portion extending in the longitudinal direction at a lower elevation than the rear portion and attached to a vehicle lateral reinforcement structure; and
a transition zone including at least an upper bend and a lower bend, linking the rear portion and the front portion;
wherein a product of an ultimate tensile strength by an average thickness of the transition zone is between 1 and 1.5 times a product of the ultimate tensile strength by an average thickness of the rear portion and wherein the transition zone is made from a material having a fracture strain of at least 0.6 and a critical bending angle of at least 75°, wherein at least part of at least one of rear rails is made by cold stamping a material having a tensile strength of at least 950 MPa,
wherein the material has a chemical composition having in weight %: 0.13%<C<0.25%, 2.0%<Mn<3.0%, 1.2%<Si<2.5%, 0.02%<AI<1.0%, with 1.22%<Si+AI<2.5%, Nb<0.05%, Cr<0.5%, Mo<0.5%, Ti<0.05%, a remainder being Fe and unavoidable impurities and having a microstructure comprising between 8% and 15% of retained austenite, a microstructure remainder being ferrite, martensite and bainite, wherein a sum of martensite and bainite fractions is between 70% and 92%.