Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D25/00—Superstructure or monocoque structure sub-units; Parts or details thereof not otherwise provided for
  • B62D25/08—Front or rear portions
  • B62D25/14—Dashboards as superstructure sub-units
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
  • B60K37/00—Dashboards
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D21/00—Understructures, i.e. chassis frame on which a vehicle body may be mounted
  • B62D21/15—Understructures, i.e. chassis frame on which a vehicle body may be mounted having impact absorbing means, e.g. a frame designed to permanently or temporarily change shape or dimension upon impact with another body
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
  • B62D—MOTOR VEHICLES; TRAILERS
  • B62D27/00—Connections between superstructure or understructure sub-units
  • B62D27/02—Connections between superstructure or understructure sub-units rigid
  • B62D27/023—Assembly of structural joints

Definitions

• the present invention relates to structural parts for an automotive vehicle and in particular to the dash panel assembly of a vehicle.
• Car makers are submitted to ever more demanding requirements. They are requested to increase the passive safety of vehicles and at the same time to reduce the vehicle weight in order to minimize greenhouse gas emissions for internal combustion engines or increase the vehicle’s driving range for electric vehicles. At the same time, vehicle production costs must stay low and productivity rates high. Furthermore, car makers are looking to simplify vehicle production by lowering the number of separate individual parts making up a vehicle.
• the dash panel assembly separates the front motor compartment from the passenger compartment. It is a large assembly comprising several sub-parts, typically around ten individual sub-parts. It extends over the entire width of the vehicle and over a substantive portion in the elevation direction. It is involved in absorbing the crash energy and resisting intrusion in the case of a frontal crash or in the case of side impacts. It is an important structural element and one of the key passenger safety components. It also plays a significant role in ensuring the overall rigidity of the body in white.
• the object of the present invention is achieved by providing a dash panel assembly according to claim 1 , optionally comprising the features of claims 2 to 4 taken individually or according to any possible combination.
• a further object of the present invention is achieved by providing an automotive vehicle according to claim 5.
• said passenger compartment 101 needs to be protected in the case of a crash.
• the lower part of the passenger compartment is delimited by a floor panel 3, which extends transversally in between right and left side sills 6.
• the High Voltage (HV) battery housing is generally located below the floor panel 3.
• a dash panel assembly 1 is a structural part delimiting the passenger compartment 101 at its lower front end and separating it from said front motor compartment 102.
• the dash panel assembly 1 is also known as the firewall or the cowl. It extends in a generally longitudinal and elevation direction between the floor panel 3 and the windshield (not represented in the figures). It is also possible to have intermediate parts between the dash panel assembly 1 and the windshield, such as for example a cowl upper 4, as represented on figure 2.
• Said cowl upper can for example be dedicated to supporting the windshield and I or the hood hinges. In any case, said cowl upper does not play a major structural part in the vehicle and in particular does not play a role in the case of a front impact in which the elements located inside the front motor compartment are thrust backwards and impact the dash panel.
• the overlap portion 12 comprises at least one flat overlap area 122, in which the upper and lower dash panels 21 and 22 lay flat onto each other.
• the dash panel lower overlap portion 212 and the dash panel upper overlap portion 222 have the same shape so that once assembled they fit flat onto one another in said flat overlap area 122. It is possible to assemble the upper and lower dash panel 22, 21 together in the at least one flat overlap area 122, for example by resistance spot welding or by laser welding.
• the flat overlap area 122 further offers the technical advantage of having a greatly increased resistance against intrusion because two layers of formed sheet metal are available in this area to resist intrusion conjointly.
• the hollow portion 120 is formed by designing substantially horizontal walls in the dash panel upper overlap portion 212 over the entire width of the part and also by designing substantially horizontal walls in the side sections of the dash panel lower overlap portion 222 - the central portion of the dash panel lower overlap portion 222 is kept substantially flat in the hollow portion 120, acting as a flat closing plate of the inner volume.
• this design allows to create larger hollow volumes in the sides of the dash panel assembly, allowing to further resist intrusion on the sides. This is particularly useful in the case of a front impact with a small overlap during which the load will mainly be applied on one side only of the part.
• the amount of absorbed crash energy and of anti-intrusion resistance will be greater if the horizontal walls are designed in the sheet metal having the greatest mechanical resistance.
• the amount of absorbed crash energy and of anti-intrusion resistance will be greater if the horizontal walls are designed in the sheet metal having the greatest sheet metal thickness, or having the greatest yield strength, or having the greatest product of yield strength by sheet metal thickness.
• the design of the current invention allows to greatly simplify the conception and the manufacturing process of the dash panel assembly by slashing the number of sub-parts. In turn it allows to greatly reduce the number of assembly points between the sup-parts. The reduction of the number of overlap regions necessary to assemble the different sub parts, associated with an optimal choice of materials, also leads to a significant weight reduction of the assembly.
• the dash panel assembly is made by hot stamping steel sheets and the blanks used to produce it comprise one of the following materials, either in the form of monolithic blanks or combined in the form of tailor welded blanks:
• -Steel having a composition comprising in % weight: 0.06% ⁇ C ⁇ 0.1 %, 1 % ⁇ Mn ⁇ 2%, Si ⁇ 0.5%, Al ⁇ 0.1 %, 0.02% ⁇ Cr ⁇ 0.1 %, 0.02% ⁇ Nb ⁇ 0.1 %, 0.0003% ⁇ B ⁇ 0.01 %, N ⁇ 0.01 %, S ⁇ 0.003%, P ⁇ 0.020% less than 0,1 % of Cu, Ni and Mo, the remainder being iron and unavoidable impurities resulting from the elaboration.
• the yield strength of the corresponding area after hot stamping is comprised between 700 and 950MPa, the tensile strength between 950MPa and 1200MPa and the bending angle is above 75°.
• this material is used in the area corresponding to the upper portion 221 of the upper dash panel, because it absorbs energy without cracking and this area does not need to resist intrusion as much as the upper dash panel overlap portion 222.
• -Steel having an ultimate tensile strength after hot stamping which is comprised between 1300MPa and 1650MPa and a yield strength which is comprised between 950MPa and 1250MPa -Steel having an ultimate tensile strength after hot stamping which is comprised between 1300MPa and 1650MPa, a yield strength which is comprised between 950MPa and 1250MPa and a bending angle which is above 75°.
• this composition range the ultimate tensile strength of the corresponding area of the part after hot stamping is comprised between 1300MPa and 1650MPa and the yield strength is comprised between 950MPa and 1250MPa.
• this steel composition is used for the areas corresponding to the overlap portion 12 of the dash panel assembly (i.e. for the steel making up the overlap portions 212, 222 of the dash panel lower and upper). Indeed, this steel grade has high anti-intrusion properties.
• -Steel having a composition which comprises in %weight : C : 0.2 - 0.34 %, Mn: 0.50 - 1 .24 %, Si: 0.5 - 2 %, P ⁇ 0.020 %, S ⁇ 0.010 %, N ⁇ 0.010 %, and comprising optionally one or more of the following elements, by weight percent: Al: ⁇ 0.2 %, Cr
• the tensile strength of the corresponding area of the dash panel assembly after hot stamping is equal to or higher than 1000 MPa and the bending angle is higher than 55°.
• -Steel having a composition which comprises in %weight : C : 0.13 - 0.4 %, Mn: 0.4 - 4.2 %, Si : 0.1 - 2.5%, Cr ⁇ 2 %, Mo ⁇ 0.65 %, Nb ⁇ 0.1 %, Al ⁇ 3.0 %, Ti ⁇ 0.1 %, B ⁇ 0.005 %, P ⁇ 0.025 %, S ⁇ 0.01 %, N ⁇ 0.01 %, Ni ⁇ 2.0%, Ca ⁇ 0.1 %, W ⁇ 0.30%, V ⁇ 0.1 %, Cu ⁇ 0.2%, and verifying the following combination: 114 — 68*C - 18*Mn + 20*Si - 56*Cr - 60*Ni - 36*AI + 38*Mo + 79*Nb - 17691 *B ⁇ 20, the remainder of the composition being iron and unavoidable impurities resulting from the smelting.
• this composition is used
• the metallic coating is an aluminum-based coating comprising 8 - 12% in weight of Si.
• the metallic coating is applied by dipping the base material in a molten metallic bath.
• applying an aluminum-based metallic coating avoids the formation of surface scale during the heating step of the hot stamping process, which in turns allows to produce the parts by hot stamping without a subsequent sand blasting operation.
• the aluminum-based coating also provides corrosion protection to the part while in service on the vehicle.
• Sub-blanks 212A and 212B correspond to the overlap portion 212 of the lower dash panel upper once the part is formed.
• sub-blanks 21 1 A and 21 1 B correspond to the lower portion 21 1 of the dash panel lower once the part is formed.
• Sub blank 21 A spans both the overlap portion and the lower portion once the part is formed.
• the material thickness is higher on the sub blanks occupying the sides of the part (212A, 212B, 211 A, 21 1 B) than on the sub-blank occupying the center of the part (21 A). This is to provide better resistance of the part in the case of a partial overlap crash such as the ones simulated by the above detailed ODB or SORB regulatory tests. Furthermore, the blanks 212A, 212B corresponding to the sides of the overlap portion have higher thickness than the ones corresponding to the lower portion because of the necessity to have a higher anti-intrusion resistance in the overlap portion.
• the state-of-the-art assembly weighs 18.70kg, while the inventive design weighs 17.34kg, a significant 7% weight reduction.
• FIGs 9A, B to 11 A,B represent a simulated IIHS’s front overlap deformable barrier (ODB) crash test involving the above detailed specific embodiment of the invention.
• ODB front overlap deformable barrier

Landscapes

• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Transportation (AREA)
• Mechanical Engineering (AREA)
• Body Structure For Vehicles (AREA)
• Instrument Panels (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=83508666

Family Applications (1)

Country Status (8)

Family Cites Families (2)

• 2022
  • 2022-09-12 WO PCT/IB2022/058553 patent/WO2024057057A1/en not_active Ceased
• 2023
  • 2023-09-11 EP EP23768958.3A patent/EP4587313A1/de active Pending
  • 2023-09-11 KR KR1020257006614A patent/KR20250048045A/ko active Pending
  • 2023-09-11 WO PCT/IB2023/058981 patent/WO2024057171A1/en not_active Ceased
  • 2023-09-11 JP JP2025514768A patent/JP2025528585A/ja active Pending
  • 2023-09-11 CN CN202380064809.8A patent/CN119836381A/zh active Pending
  • 2023-09-11 CA CA3265198A patent/CA3265198A1/en active Pending
• 2025
  • 2025-02-05 ZA ZA2025/01132A patent/ZA202501132B/en unknown
  • 2025-03-10 MX MX2025002833A patent/MX2025002833A/es unknown

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