Rear structure for an electric vehicle

Patent metadata

Field	Value
Publication number	US-12409889-B2
Application number	US-202017640058-A
Country	US
Kind code	B2
Filing date	Jul 31, 2020
Priority date	Sep 5, 2019
Publication date	Sep 9, 2025
Grant date	Sep 9, 2025

Abstract

Rear structure for an electric vehicle having a rear rail which includes a rear portion, a front portion and a transition zone, such that in the event of a rear crash the rear portion and the transition zone are both able to deform to maximize the amount of energy absorption.

First claim

What is claimed is:

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%.

2. The rear structure as recited in claim 1 wherein the rear portion is equipped with at least one geometrical alteration locally altering a cross section.

3. The rear structure as recited in claim 1 wherein at least one of the rear rails is formed by stamping a tailor welded blank.

4. A method to produce the rear structure as recited in claim 1 , the method comprising the steps of:
providing a blank;
stamping the blank into the shape of one of the rear rails;
attaching the one rear rail to the rear bumper assembly; and
attaching the rear rail to the lateral reinforcement structure.

5. 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 %: %: 0.15%<C<0.25%, 1.4%<Mn<2.6%, 0.6%<Si<1.5%, 0.02%<AI<1.0%, with 1.0%<Si+AI<2.4%, Nb<0.05%, Cr<0.5%, Mo<0.5%, a remainder being Fe and unavoidable impurities and having a microstructure comprising between 10% and 20% of retained austenite, a microstructure remainder being ferrite, martensite and bainite.

6. The rear structure as recited in claim 5 wherein at least one of the rear rails is formed by stamping a tailor rolled blank.

7. A method to produce the rear structure as recited in claim 5 , the method comprising the steps of:
providing a blank;
stamping the blank into the shape of one of the rear rails;
attaching the one rear rail to the rear bumper assembly; and
attaching the rear rail to the lateral reinforcement structure.

8. The rear structure as recited in claim 5 wherein the rear portion is equipped with at least one geometrical alteration locally altering a cross section.

Assignees

• Arcelormittal

Inventors

• Sotty Alexandre
• Gibeau Elie
• Schneider Nicolas
• Drouadaine Yves

Classifications

• C22C38/38

  with more than 1.5% by weight of manganese · CPC title

• C22C38/32

  with boron · CPC title

• C22C38/28

  with titanium or zirconium · CPC title

• C22C38/26

  with niobium or tantalum · CPC title

• C22C38/22

  with molybdenum or tungsten · CPC title