Integrated firewall panel for vehicles

Abstract

This disclosure relates to a method for manufacturing a vehicle-type integrated firewall panel. The method includes providing a plurality of blanks, joining the blanks together to form a combined blank, and hot stamping the combined blank to form an integrated firewall panel. The disclosure further relates to an integrated firewall panel that can be obtained by such a method.

Description

Technical Field

[0001] This application claims the benefit of European Patent Application No. 23382332.7, filed on April 5, 2023.

[0002] The present disclosure relates to a firewall panel for a vehicle, and more particularly, to an integrated firewall panel for a vehicle and a method for manufacturing the integrated firewall panel for a vehicle.

Background Art

[0003] Vehicles such as automobiles incorporate a structural skeleton designed to withstand the loads that the vehicle may be subjected to during its lifespan. The structural skeleton is further designed to withstand and absorb impacts, for example, in preparation for collisions with other automobiles or road structures.

[0004] The trend towards manufacturing vehicles with lower emissions and greater efficiency has increased dramatically in recent decades. The rapid development of hybrid and electric vehicles has forced the industry to design new automotive parts, i.e., requirements such as weight reduction and thereby extended vehicle range, as well as accommodation and protection of new automotive parts are demanded. Thus, the demand for weight reduction in the automotive industry has led to the development and introduction of lightweight materials or parts and related manufacturing processes and tools. The demand for weight reduction is particularly driven by the goal of reducing CO2 emissions. The increasing concern for passenger safety has also led to the adoption of materials that improve the integrity of the vehicle during collisions and also improve energy absorption.

[0005] Press hardening, also known as hot-formed quenching (HFDQ), typically uses boron steel sheets to produce stamped parts with the properties of ultra-high-strength steel (UHSS), for example, having tensile strengths of 1,500 MPa, 2,000 MPa, or even higher. The increased strength allows for the use of thinner gauge materials, resulting in weight reductions that outperform conventional cold-stamped mild steel parts. Throughout this disclosure, UHSS can be considered steel having a maximum tensile strength of 1,000 MPa or more, particularly after the press hardening process.

[0006] In the HFDQ process, the blank to be hot-formed can be heated to a predetermined temperature, for example, above the austenitizing temperature (particularly between the evaporation temperature of Ac3 and the coating of the blank). A furnace system can be used for this purpose. Depending on specific needs, the furnace system may be supplemented with additional heaters such as induction heaters or infrared heaters. Heating the blank reduces its strength and improves its deformability, thus facilitating the hot stamping process.

[0007] Several ultra-high-strength steels (UHSS) are known for hot stamping and hardening. The blanks to be hot-formed can be made from coated or uncoated boron steel, such as Usibor® (22MnB5), commercially available from ArcelorMittal.

[0008] Typical vehicle components that can be manufactured using the HFDQ process include door beams, bumper beams, crossbars / lateral members, A / B pillar reinforcements, front / rear rails, seat crossbars, and roof rails.

[0009] It is known that introducing softer regions within a component can improve ductility and energy absorption in specific areas of the component. This locally improves ductility while maintaining the high overall strength required. By locally tuning the microstructure and mechanical properties of specific structural components so that they consist of regions with very high strength (very hard regions), i.e., regions with high maximum tensile strength and high yield strength, and regions with increased ductility (softer regions), i.e., regions with lower maximum tensile strength and lower yield strength and increased elongation before fracture, it may be possible to improve overall energy absorption, maintain structural integrity during impact, and further reduce overall weight. Such softer regions can also favorably alter the kinematic behavior when the component collapses under impact.

[0010] Known methods for creating areas of increased ductility ("soft areas" or "flexible areas") in vehicle structural components include providing a tool comprising a pair of complementary upper and lower die units, each unit having a separate die element (steel block). The blank to be hot-formed is preheated to a predetermined temperature, such as the austenitizing temperature, for example, by a furnace system, in order to reduce its strength, i.e., to facilitate the hot stamping process.

[0011] Die elements can be designed to operate at different temperatures, with the aim of varying the cooling rates in different areas of the part being formed during the quenching process, thereby resulting in various material properties of the final product, such as softer areas that generally have lower maximum tensile strength and lower yield strength but allow for greater elongation before fracture. For example, one die element can be cooled to quench a corresponding area of ​​the part being manufactured at a high cooling rate, thereby rapidly lowering the temperature of the part to obtain a hard martensite microstructure. Another adjacent die element can be heated to cool a corresponding part of the part being manufactured at a lower cooling rate to obtain a softer microstructure, such as bainite, ferrite, and / or pearlite. Such areas of the part may remain at a higher temperature than the rest of the part when they leave the die.

[0012] Other methods for obtaining hot-stamped parts with areas having different mechanical properties include, for example, pre-stamping adjustment or differentiated heating, and localized heat treatment after the stamping process, to alter the local microstructure and obtain different mechanical properties. Yet another possibility is patchwork blanks, as well as tailor-welded blanks (TWBs) that combine blanks of different thicknesses and / or materials.

[0013] UHSS can exhibit high tensile strengths of 1,500 MPa or even over 2,000 MPa, especially after press hardening. Once hardened, UHSS may possess a martensite microstructure. This microstructure allows for increased maximum tensile strength and yield strength per unit weight.

[0014] In addition to the aforementioned ultra-high-strength steels, more ductile steels may be used in structural frameworks requiring energy absorption. These steels can be used in the hot stamping process, but they do not achieve a martensitic microstructure. Ductibor® 1000 is an example of a suitable more ductile steel.

[0015] A vehicle such as an automobile comprises a passenger compartment or cabin, which is a space adapted to accommodate the driver and other passengers, and an engine compartment located in front of the passenger compartment, which in particular houses the motor.

[0016] The passenger compartment is separated from the engine compartment by a so-called "firewall." These firewalls are generally made of lightweight materials and insulate the cabin from engine noise and heat.

[0017] Firewalls are generally manufactured by welding together different workpieces that have been pre-cold-stamped or otherwise formed. These workpieces typically vary in thickness and are made from multiple different materials, particularly those suitable for cold stamping.

[0018] Firewalls are generally not designed or configured to withstand or absorb impacts in the event of a collision with another vehicle, other vehicle, or obstacle. For this reason, reinforcing members are known to be provided, which are generally welded to the firewall so that the firewall has elements that distribute the impact force to the vehicle's structural frame, such as rockers or hinge pillars, in the event of a collision.

[0019] Firewalls are manufactured separately from reinforcing materials, which vary in size and shape depending on the specifications of the firewall being installed. These reinforcing materials include various thicknesses and materials, enabling the firewall to achieve the required rigidity. For example, such reinforcing materials can be made from press-hardened boron steel.

[0020] One of the problems we have faced so far is that manufacturing firewalls by welding multiple stamped workpieces together is a time-consuming process, which can result in weak points in the structure. Another issue to consider is that reinforcing materials welded to the firewalls to increase resistance to impact loads may increase the weight of the vehicle.

[0021] This disclosure provides examples of systems and methods that offer improvements over prior art firewalls. [Overview of the Initiative]

[0022] In a first embodiment, a method for manufacturing a firewall panel is provided. This method includes providing a plurality of blanks, joining the blanks to form a combined blank, and hot stamping the combined blank to form a single firewall panel.

[0023] By joining blanks together to form a bonded blank, and then hot-stamping the bonded blank, post-formation welding is reduced, resulting in a lightweight, durable, one-piece firewall panel constructed with fewer steps. Avoiding or reducing post-formation welding also reduces the area affected by the corresponding heat. The one-piece firewall panel can improve impact performance while maintaining a lightweight design.

[0024] Hot stamping is a process that, for example, appropriately deforms ultra-high-strength steel, enabling the formation of complex structures for integrated firewall panels.

[0025] In some cases, blanks of different material thicknesses and / or grades can be used to meet specific strength and energy absorption and distribution requirements and to optimize weight.

[0026] In some examples, joining blanks involves forming one or more overlapping regions by partially overlapping the blanks with each other. In this disclosure, partially overlapping two blanks means that only portions of the two blanks overlap.

[0027] One or more overlapping regions can provide a region with a greater thickness by means of a firewall panel, thereby distributing collision energy to the structural components of the vehicle skeleton. It is possible to provide a firewall that also has a structural function, rather than just a physical partition between the engine compartment and the passenger cabin. The integrated firewall panel may be more rigid and preferably can distribute collision energy without the need to weld additional reinforcing materials. Thus, it is possible to achieve an improvement in the collision performance of the vehicle with fewer components.

[0028] In some examples, an overlapping region can be formed along the longitudinal direction of the integrated firewall panel. In this specification, the longitudinal direction can be considered as a direction substantially transverse to the longitudinal direction of the vehicle. In the case of a frontal collision, the overlapping region can impart rigidity to the firewall panel and distribute impact energy to the sides of the firewall panel and to the structural elements of the vehicle. Reinforcement can be applied to regions that are vulnerable to impact loads, improving the collision performance of the firewall panel.

[0029] In other examples, an overlapping region can be formed along the vertical direction of the integrated firewall panel. It is possible to provide a more rigid firewall panel that distributes impact loads to structural elements of the vehicle, such as rockers, tunnels, or hinge pillars. The overlapping region can be positioned on the first lateral side or both lateral sides of the body firewall panel. The overlap along the vertical direction can also be positioned in a substantially central area and the lower half of the firewall panel. Such an overlap locally strengthens the firewall panel and can direct loads to, for example, a tunnel.

[0030] In some examples, the deformation of the joining blank can be performed in a single operation. As a result of deforming the joining blank in one operation, the efficiency of the manufacturing process of the vehicle's firewall panel can be improved.

[0031] In several examples, the joining blank is provided with a thickened area (either by an overlapping area or by providing a patch blank, for example) for the purpose of providing a load path for directing loads to, for example, hinge pillars, floors, or tunnels. Such a thickened area can be positioned so that the area of ​​the firewall panel joined to other parts of the vehicle framework has increased strength and rigidity. Such a thickened area may extend, for example, from the central area of ​​the firewall panel (centered horizontally and / or vertically) toward the area where the firewall panel is joined to other parts of the vehicle structural framework, particularly rockers, floors, tunnels, hinge pillars, or A-pillars.

[0032] In a further embodiment, an integrated firewall panel is provided, such as one obtained by a method according to any of the examples described herein.

[0033] The following describes some non-limiting examples of this disclosure, with reference to the attached diagrams. [Brief explanation of the drawing]

[0034] [Figure 1] This figure shows an example of a vehicle firewall using conventional technology. [Figure 2a] This figure shows examples of multiple blanks before they are joined together to form a combined blank. [Figure 2b] This figure shows an example of a bonded blank formed by two joined blanks. [Figure 3a] This figure shows further examples of multiple blanks before they are joined together to form a combined blank. [Figure 3b] This figure shows an example of a bonded blank formed by two joined blanks in Figure 3a. [Figure 4] This figure shows an example of a combined blank with a patch blank. [Figure 5] This figure shows a further example of a combined blank with multiple patch blanks. [Figure 6] This figure shows an example of an integrated fireproof wall panel for a vehicle according to this disclosure. [Figure 7] This is a flowchart of the method for manufacturing integrated firewall panels for vehicles. [Modes for carrying out the invention]

[0035] The figures illustrate exemplary embodiments and should be used solely as an aid to understanding the claimed subject matter, and should not be limited in any way.

[0036] In these diagrams, the same reference numerals are used to indicate matching elements.

[0037] Figure 1 schematically shows a conventional firewall panel. The firewall panel is manufactured from a plurality of independent cold-formed parts 1, which are then welded together. The plurality of cold-formed parts may have different shapes and different thicknesses. The firewall panel is merely a physical partition between the engine compartment and the passenger cabin of a vehicle and is not configured to withstand or absorb impact in the event of a collision with another vehicle, for example.

[0038] Furthermore, the firewall panel includes multiple horizontal members 2 or reinforcing members extending along the longitudinal direction of the firewall panel. These horizontal members 2 are welded to the firewall panel and function as reinforcement in the event of a collision.

[0039] In one aspect of this disclosure, an integrated firewall panel 100 is provided. The integrated firewall panel 100 is manufactured from a plurality of blanks that are joined together to form a bonded blank. The integrated firewall panel is obtained after hot stamping of the bonded blanks. Thus, an integrated firewall panel with improved impact performance can be obtained.

[0040] As schematically shown in Figure 2a, the integrated firewall panel 100 can be manufactured by joining a first blank 10 and a second blank 20 to form a combined blank 30. In the example in Figure 2a, the first blank 10 can define the upper portion of the firewall panel, while the second blank 20 can define the lower portion of the firewall panel. In other examples, the integrated firewall panel 100 can be manufactured by joining blanks that define other portions of the firewall panel, or by joining three or more blanks.

[0041] The thickness of the blanks is 0.5 to 5 mm, preferably 0.8 to 3 mm. In some examples, the thicknesses of the various blanks may be substantially the same. In other examples, blanks of different thicknesses may be desired depending on their position in the firewall panel, and blanks of different thicknesses can be joined to form a combined blank. Furthermore, the multiple blanks 10, 20 forming the combined blank 30 may be made from different materials. In some examples, the blanks 10, 20 can be made from ultra-high-strength steel (UHSS), such as Usibor® or Ductibor®. In other examples, aluminum blanks, such as 6000 or 7000 series aluminum, can be used.

[0042] A combined blank 30 containing two blanks 10 and 20 can be formed in this way, as shown in Figure 2b, by joining the first blank 10 and the second blank 20. Joining the blanks can involve forming one or more overlapping regions formed by partially overlapping the blanks with each other, that is, one blank can be partially positioned on top of another blank, and the blanks are then joined together. In some examples, the overlapping region may have a width of at least 5 cm. The overlapping region thus acquires an increased thickness compared to the rest of the blank. This increase in thickness can be used to adjust the mechanical properties as needed and to provide local strength and / or rigidity in areas where reinforcement is required in the prior art of integrated fireproof wall panels.

[0043] Furthermore, overlapping regions can be used to distribute impact energy to other parts of the vehicle. The overlapping regions may have load paths that can transfer impact energy to other elements of the vehicle configured to absorb such energy. For example, in a frontal collision, the impact load can be transmitted through the entire firewall to structural elements of the vehicle designed to absorb the energy generated during the collision. This avoids the need for additional structural reinforcement in the firewall panels, improving the impact performance of the firewall while reducing the number of components.

[0044] The blanks can be joined using laser welding, spot welding, or arc welding.

[0045] Referring again to Figure 2b, when the first blank 10 and the second blank 20 of Figure 2a are joined, an overlapping region 40 may be formed along the longitudinal direction of the integrated firewall panel. The overlapping region 40 can form a horizontal strip in the lower half of the firewall panel; that is, the overlapping region 40 may be a substantially linear region offset vertically from the center toward the bottom of the joining blank 30. The overlapping region 40 may extend from the first end to the second end of the joining blank 30, i.e., across the entire length of the firewall panel (or substantially across the entire width of the vehicle). Furthermore, both ends of the overlapping region may be aligned vertically.

[0046] In a frontal collision, the overlapping region along the longitudinal direction can provide rigidity to the firewall panel, allowing impact energy to be distributed to the vehicle's structural elements. This may eliminate the need for additional structural reinforcement in the firewall panel. Thus, an integrated firewall panel can be obtained that includes longitudinal reinforcement capable of distributing collision loads, for example, in a frontal collision with another vehicle. Therefore, an integrated firewall that can be manufactured with fewer parts and distribute collision energy can be provided.

[0047] In some examples, the overlapping region may have a length L1 corresponding to the length of the integrated firewall panel 100. In the example of Figure 2b, the overlapping region may have a length L1 corresponding to the length of the integrated firewall panel and a width W1 of at least 1 cm, for example, 1 to 5 cm. In some examples, the width of the overlapping region may be at least 5 cm. In some examples, the width of the overlapping region does not have to be constant; for example, the overlapping region may widen towards the central part of the joint blank 30. An appropriate dimension of the overlapping region 40 can be selected considering the requirements of weldability, strength, rigidity, and energy distribution. A larger overlapping region 40 means an increase in thickness over a wider area, resulting in locally increased strength and rigidity in the integrated firewall panel 100, as well as improved energy distribution.

[0048] In the subsequent process, the bonded blank 30 is hot-stamped to form an integrated firewall panel. In particular, the bonded blank can be heated in a furnace to a temperature above the austenitization temperature, for example, about 900-920°C. After that, the bonded blank can be deformed and hardened using a press. In particular, rapid cooling exceeding the critical cooling rate of the bonded blank can achieve a martensitic microstructure, high maximum tensile strength, and high yield strength.

[0049] In some examples, partially overlapping the blanks may include forming substantially vertically overlapping regions of the integrated firewall panel 100.

[0050] Figure 3a shows another example of joining a first blank 10 and a second blank 20 to form a combined blank 30. As shown, the blank in Figure 3a has a different shape from the blank in the example in Figure 2a, and therefore, by partially overlapping the blanks 10 and 20 with each other, a different overlapping region 40 is obtained than that in Figure 2b.

[0051] In the example shown in Figure 3b, a substantially U-shaped overlapping region can be formed by partially overlapping the blanks 10 and 20 with each other. In addition to the overlapping region 40 formed in Figure 2b, one or more overlapping regions 50, 60 can be formed along the vertical direction of the integrated firewall panel 100, such that the overlapping regions may be located on the first lateral side of the integrated firewall panel 100. Figure 3b shows the first lateral side of the bonded blank 30 with the first vertical overlapping region 50 and the second lateral side of the bonded blank 30 with the second vertical overlapping region 60. In some examples, the vertical overlapping regions may have a width of at least 1 cm, preferably at least 5 cm. Overlapping regions located on the lateral side of the integrated firewall panel can provide additional thickness in that region, and can provide an integrated firewall panel that can distribute loads from a frontal collision to, for example, the vehicle's rocker and / or hinge pillars.

[0052] Furthermore, the size and shape of the blank may depend on where the overlapping regions 40, 50, and 60 are desired within the blank. In another example, a first blank that can define the left side of the firewall panel can be joined to a second blank that can define the right side of the panel to form a vertical overlapping region substantially in the center of the firewall panel. This can result in a one-piece firewall panel that may have increased rigidity in the central part and substantially along the vertical direction, and which may be able to distribute impact loads to structural elements of the vehicle body, such as tunnels.

[0053] As schematically shown in Figure 4, in some examples, the patch blank 70 can be joined to at least one of the multiple blanks forming the joint blank 30. The patch blank 70 may also be added substantially to the central portion of one of the blanks. The patch blank 70 can be added as reinforcement to increase strength and distribute the impact load from a specific area of ​​the joint blank 30 to structural parts of the vehicle configured to absorb impact energy, such as the floor tunnel and rockers.

[0054] In this particular example, the patch blank 70 is added to the central portion of the blank 20, substantially below the center of the coupling blank 30, allowing load energy to be transferred to the vehicle's tunnel. In other examples, the patch blank 70 may be positioned along the vertical direction of the coupling blank 30, optionally on the first lateral side of the coupling blank. Thus, impact loads can be distributed to the vehicle's hinge pillars and / or rockers.

[0055] The patch blanks 70 can be joined by overlapping one blank onto the other using spot welding. In other cases, alternative welding techniques such as laser welding or arc welding can be used.

[0056] Figure 5 schematically shows a further example of a jointed blank 30 having four patch blanks. As shown in Figure 6, a first patch blank 71 can be joined to the lower central portion of the blank, thereby directing the impact load to the tunnel of the vehicle floor in the event of an impact. A second patch blank 72 and a third patch blank 73 can be joined to the upper portion of the jointed blank, i.e., the upper half of the panel. The second and third patch blanks are shown positioned offset from the vertical centerline of the panel.

[0057] Furthermore, the blank 10 in Figure 6 may extend longitudinally from end to end of the connecting blank and may also include a fourth patch blank 74 which may be located between the first patch blank 71, the second patch blank 72, and the third patch blank 73. In other examples, the connecting blank may include additional or fewer patch blanks depending on where increased strength and / or distribution of impact loads are desired in the integrated firewall panel.

[0058] In other examples, the blanks 10, 20 joined to form a joint blank 30 may be formed by multiple blanks or subblanks of different thicknesses and / or materials, for example. In these examples, the multiple blanks may be tailor-welded blanks (TWBs). TWBs can be formed by joining subblanks by welding their edges together, and the welding may include laser welding. In other examples, the multiple blanks joined to form a joint blank may be joined by forming one or more overlapping regions formed by partially overlapping the blanks. In such cases, laser welding, arc welding, or spot welding can be used.

[0059] In some examples, the multiple blanks 10, 20 forming the combined blank 30 may be made from different materials. In some examples, the blanks 10, 20 may be made from ultra-high-strength steel (UHSS). Boron steel, e.g., 22MnB5, or other steel compositions described or mentioned earlier may be suitable UHSS. These blanks, e.g., boron steel blanks, may have an aluminum-silicon coating or a zinc coating.

[0060] Usibor® 1500P is an example of 22MnB5 steel. The composition of Usibor®, summarized in weight percent, is as follows (the remainder being iron (Fe) and impurities): Maximum carbon (C) (%): 0.25 Maximum silicon (Si) (%): 0.4 Maximum manganese (Mn) (%): 1.4 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01~0.1 Maximum Titanium (Ti) (%): 0.05 Maximum niobium (Nb) (%): 0.01 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum chromium (Cr) (%): 0.35

[0061] Usibor® 1500P may have, for example, a yield strength of 1,100 MPa and a maximum tensile strength of 1,500 MPa.

[0062] Usibor® 2000 is another boron steel with even higher strength. Usibor® 2000 can have a yield strength of over 1,400 MPa and a maximum tensile strength exceeding 1,800 MPa. The composition of Usibor® 2000, summarized in weight percent, is as follows (the remainder being iron (Fe) and impurities): Maximum carbon (C) (%): 0.36 Maximum silicon (Si) (%): 0.8 Maximum manganese (Mn) (%): 0.8 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01~0.06 Maximum Titanium (Ti) (%): 0.07 Maximum niobium (Nb) (%): 0.07 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum chromium (Cr) (%): 0.50 Maximum molybdenum (Mb) (%): 0.50

[0063] The multiple blanks forming the bonded blank 30 may be made of different materials and / or have different thicknesses. For example, blanks made of Usibor® (e.g., Usibor® 1500 and / or Usibor® 2000) can be used to form the bonded blank 30. When this type of material is used in the hot forming and subsequent quenching process, the martensitic structure becomes dominant in Usibor®. One or more of the blanks may be made from different, particularly more ductile, materials, such as Ductibor® 1000.

[0064] Ductibor® 1000 is a different material used to increase elongation in hot stamping compared to Usibor® 1500 and Usibor® 2000. Ductibor® 1000 can have a yield strength of 800 MPa or higher and a maximum tensile strength of 1000 MPa or higher. The composition of Ductibor® 1000, summarized by weight percentage, is as follows (the remainder being iron (Fe) and impurities): Maximum carbon (C) (%): 0.10 Maximum silicon (Si) (%): 0.6 Maximum manganese (Mn) (%): 1.8 Maximum phosphorus (P) (%): 0.03 Maximum sulfur (S) (%): 0.01 Aluminum (Al) (%): 0.01~0.1 Maximum Titanium (Ti) (%): 0.05 Maximum niobium (Nb) (%): 0.10 Maximum copper (Cu)(%):0.20 Maximum boron (B) (%): 0.005 Maximum chromium (Cr) (%): 0.20

[0065] In other examples, the multiple blanks 10, 20 forming the combined blank 30 may be made from aluminum. The aluminum of the multiple blanks may be an aluminum alloy selected from the 6000 and 7000 series aluminum alloy groups. The characteristics of these systems are their strength, corrosion resistance, and weldability.

[0066] In some examples, the integrated fireproof wall panel 100 may comprise multiple areas having different maximum tensile strengths, according to any of the examples described herein. In some of these examples, different materials may be used for the bonding blank 30.

[0067] In some of these examples, areas with different maximum tensile strengths may have different microstructures.

[0068] Various microstructures can be created in the hot-formed firewall panel 100. These various microstructures can be created by heating the bonded blank 30 above its austenitizing temperature and then controlling the cooling of the bonded blank 30 while shaping the bonded blank 30 to form the integrated firewall panel 100 for the vehicle. Cooling of different areas of the bonded blank 30 can be controlled by providing heaters in areas with the forming tools. Thus, the integrated firewall panel 100 comprises areas having a martensite-based structure and areas having ferrite, pearlite, or bainite, or mixed structures thereof. Alternatively, different microstructures can also be created by partially heating a portion of the press-hardened integrated firewall panel, for example using a laser beam, to change the martensite-based structure to one containing ferrite and / or pearlite and / or bainite and / or tempered martensite and mixed structures thereof. The tensile strength of a martensite-based structure can exceed 1400 MPa, and especially exceed 1500 MPa.

[0069] The integrated firewall panel 100 can thus be manufactured from a material that can be effective in absorbing energy during impact. In some examples, multiple blanks 10, 20 can be manufactured from at least ultra-high-strength steel.

[0070] Multiple blanks can have a maximum tensile strength of 1,000 to 2,000 MPa, particularly 1,500 to 2,000 MPa.

[0071] In some examples, the thicknesses of multiple blanks may differ; for example, the thickness of the first blank 10 may differ from the thickness of the second blank 20.

[0072] In some cases, joining blanks to each other involves welding the blanks to each other. In some cases, the blanks may be welded by spot welding and / or laser welding. Joining the blanks before deformation can make joining easier because the blanks are substantially flat at the time of joining. Welding the blanks before the deformation process by laser welding and / or spot welding can be efficient and precise.

[0073] In some examples, hot stamping or hot forming of a bonded blank may include heating the bonded blank 30 above its austenitizing temperature and then forming the bonded blank 30 to produce a single, integrated firewall panel 100. In some examples, forming may involve two or more forming steps. These forming steps may include, for example, shaping, trimming, or cutting, and may be performed in a single multi-stage press. Examples of multi-stage presses are known, for example, from U.S. Patent No. 9,492,859B2 and International Patent Publication No. 2016142367A1.

[0074] The deformation may involve hot forming, i.e., heating the bonded blank 30 in an oven, possibly above the austenitizing temperature, particularly above Ac3. After heating in the oven, the bonded blank 30 can be transferred to a press, where it is deformed to obtain the final shape of the integrated firewall panel 100. Quenching can be performed during and immediately after forming. In particular, quenching may include cooling above the critical cooling rate to obtain a martensitic microstructure. In some examples, quenching can be avoided in selected portions of the firewall panel.

[0075] In some cases, the transformation can be performed in a single operation.

[0076] Figure 6 schematically shows an integral firewall panel 100 according to an example of the present disclosure. The integral firewall panel 100 is manufactured from a plurality of blanks that are joined together to form a bonded blank. The integral firewall panel is obtained after hot stamping of the bonded blanks.

[0077] In some examples, the integrated firewall panel 100 can be positioned between the passenger compartment and the engine compartment of a vehicle and can be joined to other parts of the vehicle framework, such as hinge pillars and the floor, for example, by welding.

[0078] It is possible to provide a firewall that is no longer merely a physical partition between the engine compartment and the occupant's cabin. The integrated firewall panel 100 of this disclosure can have increased rigidity and can have a load path that can transmit the impact load generated in the event of a collision to other parts of the vehicle designed to absorb such impact loads, such as hinge pillars, A-pillars, rockers, or floor tunnels. Furthermore, the integrated firewall panel can be produced in fewer processes. Thus, collision performance can be improved while avoiding the need to weld additional structural reinforcements to the firewall panel.

[0079] Figure 7 shows a flowchart of a manufacturing method 200 for a vehicle integrated firewall panel. This method includes providing a plurality of blanks 202, joining the blanks to each other to form a combined blank 204, and hot stamping the combined blank to form an integrated firewall panel 206.

[0080] In some examples, the multiple blanks 10, 20 forming the combined blank 30 may be made from different materials. In some examples, the multiple blanks 10, 20 may be made from ultra-high-strength steel or aluminum.

[0081] In some examples, joining blanks together to form a combined blank 202 may involve forming one or more overlapping regions 40, 50, 60 formed by partially overlapping the blanks. The overlapping regions result in increased thickness, which can give rigidity to the integrated firewall panel and can be used to distribute impact energy to other parts of the vehicle.

[0082] The overlapping area can be positioned to provide a load path for directing loads to, for example, hinge pillars, floors, or tunnels. The overlapping area can also be positioned so that the area of ​​the firewall panel joined to other parts of the vehicle framework has increased strength and rigidity.

[0083] In some examples, overlapping regions can be formed along the longitudinal direction of the integrated firewall panel. This allows for the provision of integrated firewall panels that may have higher rigidity in the longitudinal direction and may be capable of distributing impact loads to the vehicle's structural components.

[0084] Forming a one-piece firewall panel 206 by hot stamping or hot forming a bonded blank may involve creating various microstructures in the hot-formed firewall panel. These various microstructures can be created by heating the bonded blank 30 above its austenitizing temperature. In some examples, quenching may be performed during and after forming. Quenching may involve cooling above a critical cooling rate to obtain a martensitic microstructure.

[0085] In some cases, various microstructures can be obtained by heating the bonded blank 30 above its austenitizing temperature and then controlling the cooling of the bonded blank 30 while shaping it to form an integrated firewall panel 100. In some cases, quenching can be avoided in selected portions of the integrated firewall panel 100.

[0086] In some cases, hot stamping of bonding blanks to form a single-piece firewall panel 206 can be done in a single operation.

[0087] While this specification discloses only a few examples, other alternatives, modifications, uses, and / or equivalents are possible. Furthermore, this includes all possible combinations of the examples described. Therefore, the scope of this disclosure should not be limited by any particular example, but should be determined solely by a fair reading of the subsequent claims.

Claims

1. A method for manufacturing an integrated firewall panel (100) for a vehicle, wherein the method is To provide multiple blanks (10, 20), The blanks are joined together to form a combined blank (30), This includes hot stamping a bonding blank (30) to form an integrated fireproof wall panel (100), Joining the blanks includes forming one or more overlapping regions (40, 50, 60) by partially overlapping the blanks with each other. The overlapping region (40) is formed along the longitudinal direction of the integrated firewall panel and / or A method wherein the overlapping region is formed along the vertical direction of the integrated firewall panel (100) and is located on the first side and the second side of the integrated firewall panel.

2. The method according to claim 1, wherein the overlapping region (40) formed along the longitudinal direction of the integrated firewall panel extends along the entire length of the integrated firewall panel.

3. The method according to claim 1, wherein the integrated firewall panel comprises a substantially U-shaped overlapping region.

4. The method according to any one of claims 1 to 3, wherein the width of the overlapping region is at least 5 cm.

5. The method according to any one of claims 1 to 4, wherein the deformation is performed in a single operation.

6. The method according to any one of claims 1 to 5, wherein the bonding blank (30) includes at least a patch blank (70).

7. The method according to claim 6, wherein the patch blank (70) is arranged along the vertical direction of the bonding blank.

8. The method according to claim 7, wherein the patch blank (70) is positioned on the first lateral side of the bonding blank.

9. The method according to any one of claims 6 to 8, wherein the patch blank (70) is positioned in a substantially central lower portion of the bonded blank.

10. The method according to any one of claims 1 to 9, wherein joining the blanks includes welding the blanks together.

11. The method according to claim 10, wherein the welding includes laser welding.

12. The method according to any one of claims 1 to 11, wherein the plurality of blanks (10, 20) are made of ultra-high-strength steel.

13. The method according to any one of claims 1 to 11, wherein the plurality of blanks (10, 20) are made of aluminum.

14. An integrated fireproof wall panel (100) obtained by the method described in any one of claims 1 to 13.

15. A vehicle comprising the integrated firewall panel (100) described in claim 14.

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