Component and method for vehicle

Abstract

The present disclosure relates to a component for a vehicle frame, the component comprising a main frame (100) extending from a front end (200) to a rear end (300) in a longitudinal direction of the vehicle frame. The main frame (100) substantially defines a closed annular shape and includes a first side beam (110) and a second side beam (120) and a first cross beam (130) and a second cross beam (140). Further, the main frame (100) is formed by deforming a single blank. The present disclosure further relates to a method for manufacturing such a component.

Description

[0001] This application claims the benefit of European patent application No. 22 382 870.8 filed on September 21, 2022. Technical Field

[0002] The present disclosure relates to components for vehicle frames, the components including a main frame defining a substantially annular shape. The present disclosure also relates to methods for making such components. Background Art

[0003] Vehicles such as cars contain a structural framework designed to withstand the loads that the vehicle may be subjected to during its service life. The structural framework is further designed to withstand and absorb shock in the event of, for example, a collision with another car or road structure.

[0004] The trend toward lower-emission and more efficient vehicles has increased dramatically over the past few decades. The rapid development of hybrid and electric vehicles has forced the industry to design new vehicle components, both to reduce weight to achieve increased vehicle range and to accommodate and protect new vehicle components.

[0005] The automotive industry's demand for weight reduction has led to the development and implementation of lightweight materials and components, as well as related manufacturing processes and tools. This demand for weight reduction is particularly driven by the goal of reducing CO2 emissions. The increasing focus on occupant safety has also led to the adoption of materials that improve vehicle integrity and energy absorption during a crash.

[0006] A process called Hot Forming Die Quenching (HFDQ) typically uses thin sheets of boron steel to produce stamped parts with the properties of Ultra High Strength Steel (UHSS), with a tensile strength of, for example, 1500 MPa or 2000 MPa or even higher. The increase in strength allows the use of thinner gauge material, which results in a weight reduction compared to conventional cold stamped mild steel parts. Throughout this disclosure, UHSS can be considered to be steel with an ultimate tensile strength of 1000 MPa or higher after the press hardening process.

[0007] In the HFDQ process, the blank to be hot-formed can be heated to a predetermined temperature, such as the austenitizing temperature or higher (and particularly between Ac3 and, for example, the evaporation temperature of the blank's coating). A high-temperature furnace system can be used for this purpose. Depending on specific needs, the high-temperature furnace system can be supplemented with additional heaters, such as induction heaters or infrared heaters. By heating the blank, its strength is reduced and its deformability is increased, facilitating the hot stamping process.

[0008] There are several known ultra high strength steels (UHSS) for hot stamping and hardening. The blank may be made of, for example, coated or uncoated boron steel, such as is commercially available from ArcelorMittal (22MnB5).

[0009] Hot forming die quenching may also be referred to as “press hardening” or “hot stamping.” These terms will be used interchangeably throughout this disclosure.

[0010] Hot forming of boron steels is becoming increasingly popular in the automotive industry due to their superior strength and formability. Consequently, many structural components traditionally cold-formed from mild steels are being replaced with hot-formed equivalents, which offer significantly increased strength. This allows for a reduction in material thickness (and therefore weight) while maintaining the same strength. However, hot-formed components, in the conditions in which they are formed, may offer low levels of ductility and energy absorption.

[0011] In order to improve the ductility and energy absorption of specific areas of a component, it is known to introduce softer areas within the same component. This improves ductility locally while maintaining the desired high strength overall. By locally tailoring the microstructure and mechanical properties of certain structural components so that they include areas with very high strength (very hard), i.e., high ultimate tensile strength and high yield strength, and areas with increased ductility (softer), i.e., lower ultimate tensile strength and lower yield strength and increased elongation before fracture, it is possible to improve the overall energy absorption of these structural components and maintain their structural integrity during a crash situation while also reducing their overall weight. Such soft areas can also advantageously modify the kinematic behavior in the event of a component collapse under impact.

[0012] A known method for producing an area of ​​increased ductility ("soft zone") in a structural component of a vehicle comprises providing a tool comprising a pair of complementary upper and lower die units, each of which has a separate die element (steel block). The blank to be hot-formed is preheated to a predetermined temperature, such as the austenitizing temperature or higher, by, for example, a high-temperature furnace system, in order to reduce the strength, i.e., to facilitate the hot stamping process.

[0013] Mold elements can be designed to operate at different temperatures so that different regions of the part being formed experience different cooling rates during the quenching process, resulting in different material properties in the final product, such as softer regions that typically have lower ultimate tensile strength and yield strength, but allow for greater elongation before fracture. For example, one mold element can be cooled to quench a corresponding region of the part being manufactured at a high cooling rate, thereby rapidly reducing the part's temperature and achieving a hard martensitic microstructure. Another, adjacent mold element can be heated to ensure that the corresponding portion of the part being manufactured cools at a lower cooling rate, resulting in a softer microstructure, including, for example, bainite, ferrite, and / or pearlite. Such regions of the part can be maintained at a higher temperature than the rest of the part as it exits the mold.

[0014] Other methods for obtaining hot stamped parts with different mechanical properties include, for example, customized or differential heating before stamping, and local heat treatment after the stamping process to change the local microstructure and obtain different mechanical properties. Further possible methods include the use of patchwork blanks and tailor-welded blanks (TWBs) that combine different thicknesses and / or materials in the blank.

[0015] In addition to the ultra-high strength steels mentioned previously, more ductile ductile steels can be used in parts of the structural skeleton where energy needs to be absorbed. Examples of ductile steels include 500, 1000 and CRL-340LA.

[0016] UHSS can exhibit tensile strengths as high as 1500 MPa, or even 2000 MPa or higher, particularly after a press-hardening operation. Once hardened, UHSS can have a martensitic microstructure. This microstructure increases the maximum tensile strength and yield strength per unit weight.

[0017] Some ductile steels can also be heated and pressed (i.e. used in a hot stamping process), but will not have a martensitic microstructure after this process. Therefore, they will have lower tensile strength and yield strength than UHSS, but they will have higher elongation at break.

[0018] While ductile steel enables structural components to absorb energy, controlling and predicting how these components will behave during a vehicle collision can be challenging. Furthermore, the overall weight of a vehicle frame is preferably as low as possible to reduce fuel consumption. Furthermore, enhancing energy absorption while maintaining a certain level of structural integrity is not straightforward.

[0019] Automakers are also increasingly using composite materials to try to further reduce weight.

[0020] In hybrid and electric vehicles, the introduction of relatively large battery assemblies has created a need to modify several structural components (i.e., structural components related to the newly introduced battery assemblies). These structural components should be designed so that the battery assemblies can be accommodated and also protect the battery assemblies from vehicle collisions and other external impacts, i.e., under-floor impacts. These structural components can be manufactured in various ways and can be made of various materials. Lightweight materials that improve energy absorption during a collision while also maintaining the integrity of the vehicle are desired.

[0021] The present disclosure is directed to providing improvements in integrating traction batteries into the structural framework of an automobile. Summary of the Invention

[0022] In a first aspect, a component for a vehicle frame is provided. The component includes a main frame extending from a front end to a rear end along a longitudinal direction of the vehicle frame. The main frame substantially defines a closed annular shape and includes first and second side members and first and second cross members. The main frame is formed by deforming a single blank.

[0023] According to this aspect, a component with a simplified manufacturing process is provided. Since the main frame is manufactured by deforming a single blank, manufacturing time and associated costs can be reduced. In addition, other post-manufacturing processes that may affect the mechanical properties of the component, such as welding, are avoided. At the same time, the provided component can have sufficient strength and rigidity as well as energy absorption to provide protection for the central free space of the annular shape in the event of an impact. The front and rear ends of the main frame can absorb energy in the event of a frontal or rear impact, while the side beams of the main frame can absorb energy in the event of a side impact. The annular main frame is generally designed to transfer impact loads to appropriate areas of the vehicle frame. Therefore, the main frame can reduce the acceleration in the car caused by a collision. In addition, the component can improve the protection of other vehicle components located inside the annular shape, such as the battery assembly. In addition, the main frame can prevent deformation of the safe area inside the vehicle, thereby improving the safety of passengers.

[0024] Furthermore, the component according to this aspect can provide a reduction in the weight of the vehicle compared to existing counterparts. This directly impacts the efficiency of the vehicle, i.e. a higher battery autonomy.

[0025] Throughout this disclosure, a "ring-shaped shape" may be understood as a closed shape having a central free space. This closed shape may define a substantially rectangular perimeter, a square perimeter, or a substantially elliptical perimeter, etc. Similarly, the central free space may define any suitable shape.

[0026] Furthermore, throughout this disclosure, references to "mechanical properties of a portion" may be understood to refer to the mechanical properties of the material from which the portion is formed. Thus, unless otherwise stated, comparisons of mechanical properties of parts, components, etc. relate to the material, not its geometry or other characteristics.

[0027] Throughout this disclosure, a blank may be considered to be a thin metal sheet or plate to be formed into a final product or semi-finished product. The blank to be formed into a main frame may in particular be a composite blank consisting of several blanks or "sub-blanks" of the same or different materials and / or thicknesses.

[0028] The sub-blank, a plurality of sub-blanks or all sub-blanks may be made of hardenable steel, in particular boron steel.The thickness of the blank may typically be between 0.8 mm and 3 mm.

[0029] A patch can be thought of as a blank that will form a partial patch on the main frame of a component. A blank to which a patch has been added is sometimes called a "seamless blank." This is to distinguish it from a "tailor-welded blank," in which at least two sub-blanks are joined together by edge-to-edge welding.

[0030] Higher mechanical properties are understood herein as higher ultimate tensile strength and / or higher yield strength, while lower mechanical properties are understood as lower ultimate tensile strength and / or lower yield strength. Ultimate tensile strength and yield strength are considered herein as material properties after the manufacturing process. Ultimate tensile strength and yield strength can be determined in standardized tensile strength tests, for example using A30, A50, or A80 specimens in quasi-static load tests.

[0031] Comparisons between lower and higher mechanical properties should be made using the same test conditions and specimen dimensions. To compare the yield strength of different parts, specimens can be prepared and tested in a Universal Testing Machine (UTM).

[0032] In an example, the main frame can be made by hot stamping.Thus, the main frame can have at least some of the benefits of components made by such manufacturing processes previously disclosed.

[0033] In some examples, a single blank ("combination blank") to be formed into a main frame includes at least two sub-blanks that form one or more overlapping areas. The overlapping area can be formed by partially overlapping two sub-blanks. In some examples, at least one of the overlapping areas is located in a portion of the main frame that is configured to be connected to other components of the vehicle frame, that is, the overlap is arranged in an area of ​​the combination blank so that after deformation it is arranged in a suitable part of the main frame. Due to the increased thickness at the overlap of the sub-blanks, the mechanical strength and rigidity of the overlapping area can be higher than the rest of the main frame. Providing overlapping areas in areas for connection to other parts of the vehicle frame promotes a stable connection between the components, that is, when the connection is configured to transfer loads between the components.

[0034] In another example, an overlap region may be formed at the transition between the side rails and the rear cross member.

[0035] Furthermore, using appropriate materials, the main frame can be given appropriate properties in terms of crash behavior and weight reduction by, for example, using patch welding. For example, welding the first patch to the main frame strengthens the main frame where necessary without adding additional, undesirable weight.

[0036] In one example, a patchwork blank can have overlapping soft (or "ductile") and hard materials in areas envisioned to be subject to compression or bending forces in a crash situation. In these areas, the component can withstand greater deformation (e.g., higher bend angles) without risk of fracture, and can make the vehicle safer.

[0037] Typically, the patch is joined to the main part by spot welding, a well-known and widely used welding technique in the automotive industry. Overlapping sub-blanks can also be joined by spot welding.

[0038] In some examples, a single blank may include a tailor-welded blank comprising at least two sub-blanks of varying thickness or material. In some examples, one or more of the sub-blanks that together form a combined blank may be tailor-welded. The sub-blanks may comprise materials having varying mechanical properties to adjust the strength, stiffness, and deformation characteristics of the main frame.

[0039] In an example, at least a portion of the main frame, ie the side beams and / or the cross beams, may be made of a steel having an ultimate tensile strength higher than 1500 MPa after a press hardening process.

[0040] In some examples, at least a portion of the main frame may have a substantially U-shaped cross-section. The U-shaped cross-section includes a bottom wall, a first side wall, a second side wall, a first side flange protruding outward at one end of the first side wall, and a second side flange protruding outward at one end of the second side wall. The portion having the U-shaped cross-section may be part of a member, i.e., part of a beam, or a portion extending along several members.

[0041] The U-shaped cross section provides rigidity to the main frame, is easy to manufacture and provides convenient areas, i.e. flanges, to connect with other structural elements. Throughout this disclosure, a U-shaped cross section may be understood to refer to a structural member having a bottom wall and two side walls in cross section (typically in a transverse plane substantially perpendicular to the longitudinal axis of the structural member). It is well known that a U-shaped cross section has a good moment of inertia to weight ratio. The two side walls may form an obtuse angle with the bottom wall, for example between 90° and 135°. The two side walls may include side flanges extending outwards. The bottom wall and side walls may be substantially straight, but they may also include transition portions, bends, recesses or protrusions.

[0042] In some examples, the main frame can be configured to receive the battery assembly within the central free space of the annular shape. Furthermore, in some examples, the side sills include a central region between the front and rear ends that is configured to connect to the battery assembly. Thus, the main frame can provide support and protection for the vehicle's battery assembly.

[0043] In an example, the side members are configured to connect to front and rear longitudinal members of the vehicle frame at the front and rear ends, respectively.

[0044] In some examples, each side sill is configured to be connected to a side sill of the vehicle frame. This connection can be performed horizontally, i.e., the side sill and the side sill can be one after another in a horizontal direction, or vertically, i.e., the side sill can be substantially on top of the sill, or vice versa.

[0045] The component of the present disclosure may be part of a vehicle frame, ie it may be part of the body-in-white of the vehicle.

[0046] In an example, a battery assembly (battery box or tray, battery cells, cover, etc.) can be connected to a component. The connection between the battery assembly and the main frame of the component can be performed after the component is attached to the rest of the vehicle frame. The connection between the battery assemblies can be direct, i.e., using a fastener assembly, or using an intermediate component.

[0047] In another aspect, a method for manufacturing a component for a vehicle frame is provided. The component includes a main frame substantially defining a closed annular shape and including first and second side beams and first and second cross beams.

[0048] The method includes providing a single blank. The method further includes heating the single blank to a temperature above the Ac3 austenitizing temperature and press-hardening the heated single blank to form a component.

[0049] Compared to known methods, this method offers a simpler and more efficient way to manufacture components. Furthermore, the resulting components can have a reduced weight compared to components with similar mechanical properties manufactured using other methods. Furthermore, the resulting components can have improved deformation behavior, and this method can make it possible to tailor how the component deforms during, for example, a car crash. Consequently, energy absorption and overall vehicle safety can be enhanced.

[0050] In some examples of the method, the single blank includes at least two sub-blanks, and the method further includes joining the sub-blanks to each other. The joining step may include forming one or more overlapping regions by partially overlapping the two sub-blanks. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Non-limiting examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

[0052] Figure 1 A top perspective view of an example of a component for a vehicle is schematically shown.

[0053] Figure 2 Schematically shows Figure 1 A top view of the components in .

[0054] Figure 3 Schematically shows Figure 1 Side view of the components in .

[0055] Figure 4 A top perspective view of another example of a component for a vehicle is schematically shown.

[0056] Figure 5 Schematic diagram showing the passage of components Figure 4 The cross section of plane AA in .

[0057] Figure 6 Another example of a component in a vehicle frame is schematically shown.

[0058] Figure 7 A single blank is schematically shown prior to forming into another example of a component.

[0059] Figure 8 is a flow chart of a method for manufacturing a component.

[0060] The drawings relate to exemplary embodiments and are merely intended to aid in understanding the claimed subject matter and are not intended to be limiting in any sense. DETAILED DESCRIPTION

[0061] Figure 1 A top perspective view of an example of a component for a vehicle frame is schematically shown. The component includes a main frame 100 extending from a front end 200 to a rear end 300 along the longitudinal direction of the vehicle frame. The main frame substantially defines a closed annular shape and includes a first side member 110, a second side member 120, a first cross member 130, and a second cross member 140. Furthermore, the main frame 100 is manufactured by deforming a single blank.

[0062] As in e.g. Figure 1 and Figure 2 As can be seen in FIG, the first side member 110 and the second side member 120 extend generally along the longitudinal direction of the vehicle frame. The first cross member and the second cross member generally extend in a transverse direction, ie substantially horizontally and substantially perpendicular to the longitudinal direction of the vehicle frame.

[0063] Figure 1 The example of the main frame 100 shown is also manufactured by hot stamping. For example, it can be made in a direct hot stamping manufacturing process or in an indirect hot stamping manufacturing process. In other examples, the main frame 100 can be manufactured by cold stamping or by other manufacturing processes. Figure 5 Further details regarding the manufacturing process of the component are described.

[0064] The main frame 100 of the component can have at least a portion having a substantially U-shaped cross-section. The U-shaped cross-section can have a bottom wall, a first side wall, a second side wall, a first side flange protruding outwardly at one end of the first side wall, and a second side flange protruding outwardly at one end of the second side wall. The side flanges provide convenient attachment points, such as for riveting or spot welding, to connect the main frame 100 to other parts of the vehicle (e.g., other components of the vehicle's structural frame). Once installed in the vehicle frame, the U-shape can be generally pointed upward, i.e., with the bottom wall at the bottom and the open side of the U at the top.

[0065] In addition, the bottom wall can be substantially perpendicular to the side wall. In a further example, the bottom wall can define an angle different from 90 degrees relative to the side wall. The radius of curvature between the bottom wall and the side wall can be adjusted according to the specifications of the main frame 100 (i.e., the mechanical properties of the material used, the desired maximum local strength, etc.). The radius of curvature between the side wall and the side flange can also vary according to the specifications of the main frame 100, as described above.

[0066] Figure 2 and Figure 3 Shown respectively Figure 1These figures illustrate that the main frame 100 can be configured to receive a battery assembly in a central free space 150 of an annular shape.

[0067] Furthermore, in some examples, the main frame 100 may include side beams 110, 120 having a central region 111, 121 between the front end 200 and the rear end 300, wherein the central region 111, 121 is configured to connect to a battery assembly (not shown). A battery tray or battery box may be connected to the main frame 100 via one or more brackets. For example, a battery assembly may be connected to each of the side beams using two brackets.

[0068] The main frame 100 of the components may also include one or more soft zones (not shown) having lower mechanical properties than other zones of the main frame 100. The soft zones may cover certain areas of the main frame 100 to absorb energy in the event of an impact and limit the degree of intrusion into other areas of the main frame 100. Thus, to improve battery and occupant safety, components with different mechanical properties may be provided at different locations in the main frame 100.

[0069] In some examples, the outer sidewalls of the side sills may include soft zones to absorb energy and protect the battery assembly in a side impact.

[0070] In a specific example, the portion of the main frame that is connected to the rear rail can be more ductile than other portions.In some examples, the soft zone can extend along a portion of the side rail, such as along 5% to 20% of the length of the side rail.

[0071] The yield strength of the soft zone may be between 600 MPa and 950 MPa, specifically between 650 MPa and 800 MPa. In addition, the main frame 100 of the component may have an ultimate tensile strength (outside the soft zone) of primarily 1000 MPa or more, specifically 1200 MPa or more, and more specifically 1500 MPa or more.

[0072] The main frame 100 may have a transition zone, ie a transition zone between the soft zone and the rest of the main frame 100 having a width less than 30 mm, specifically between 20 mm and 5 mm.

[0073] In some examples, the main frame 100 may be made of boron steel, such as For example 1500 (22MnB5 steel, with or without protective coating), 2000 (37MnB5) or any martensitic steel or ultra-high strength steel (UHSS). Commercially available from ArcelorMittal.

[0074] 1500 is supplied in a ferrite-pearlite phase. Its fine-grained structure is uniformly distributed. Its mechanical properties are related to this structure. After heating, the hot stamping process, and subsequent quenching, a martensitic microstructure develops. As a result, tensile and yield strengths increase significantly.

[0075] The composition of 1500 is summarized in weight percentage as follows (the rest is iron (Fe) and impurities):

[0076] Maximum carbon (C) content (%): 0.25

[0077] Maximum silicon (Si) content (%): 0.4

[0078] Maximum manganese (Mn) content (%): 1.4

[0079] Maximum phosphorus (P) content (%): 0.03

[0080] Maximum sulfur (S) content (%): 0.01

[0081] Aluminum (Al) content (%): 0.01-0.1

[0082] Maximum titanium (Ti) content (%): 0.05

[0083] Maximum niobium (Nb) content (%): 0.01

[0084] Maximum copper (Cu) content (%): 0.20

[0085] Maximum boron (B) content (%): 0.005

[0086] Maximum chromium (Cr) content (%): 0.35

[0087] 2000 is another boron steel 37MnB5 with even higher strength. After hot stamping die quenching process, The yield strength of 2000 can be 1300 MPa or higher, and its ultimate tensile strength can be higher than 1800 MPa.

[0088] The composition of 2000 is summarized in weight percentage as follows (the rest is iron (Fe) and impurities):

[0089] Maximum carbon (C) content (%): 0.36

[0090] Maximum silicon (Si) content (%): 0.8

[0091] Maximum manganese (Mn) content (%): 0.8

[0092] Maximum phosphorus (P) content (%): 0.03

[0093] Maximum sulfur (S) content (%): 0.01

[0094] Aluminum (Al) content (%): 0.01-0.06

[0095] Maximum titanium (Ti) content (%): 0.07

[0096] Maximum niobium (Nb) content (%): 0.07

[0097] Maximum copper (Cu) content (%): 0.20

[0098] Maximum boron (B) content (%): 0.005

[0099] Maximum chromium (Cr) content (%): 0.50

[0100] Maximum molybdenum (Mb) content (%): 0.50

[0101] 22MnB5 and other boron steels may have an aluminum-silicon coating to prevent decarburization and scaling during the forming process. Several 22MnB5 steels with similar chemical compositions are commercially available. However, the exact amounts of each component in the 22MnB5 steel composition can vary slightly between manufacturers. Other ultra-high-strength steels include, for example, BTR165, commercially available from Benteler.

[0102] In an example, the main frame 100 may include components made of different materials. For example, the main frame 100 may include a first UHSS (e.g., 1500 or 22MnB5) and the side members 110, 120 made of another UHSS (e.g. 2000 or 37MnB5). Other materials for each component can be selected to form a component with a given dynamic response and mechanical properties.

[0103] Figure 3 The front end 200 and rear end 300 of the main frame 100, shown as components, can be at different heights relative to the central region 121 of the side rails 120. Therefore, the main frame 100 can include a front transition region 201 and a rear transition region 301 to provide this height transition between different regions of the main frame 100. In the illustrated diagram, the front transition region 201 shows a steeper transition than the rear transition region 301. However, in other examples, this characteristic can be reversed. The radius of curvature of these transition regions 201, 301 can be adjusted to customize the stress distribution in the event of an impact.

[0104] Figure 4 and Figure 5 Another example of a component according to the present disclosure is shown. Figure 4 is a perspective view of the main frame 100 of the component, and Figure 5 Shows the pass-through of the component Figure 4 The cross section of plane AA in .

[0105] exist Figure 4 and Figure 5 In the example shown, the main frame 100 may comprise two or more sub-blanks 101, 102 which, when formed, obtain a substantially L-shaped cross section. In addition, the two sub-blanks 101, 102 together may define a substantially U-shaped cross section, as in Figure 5 . Thus, two or more sub-blanks 101, 102 can define an overlapping region 19 at the base of the U-shaped cross section. It should be clear that the sub-blanks 101, 102 are connected to each other when they are both substantially flat plates, that is, one sub-blank can be positioned to partially overlap the other sub-blank, and the sub-blanks can then be connected, for example, by welding. Once connected to each other (and optionally after being connected to another sub-blank), the combined blank can be deformed to obtain the shown annular component with a U-shaped cross section.

[0106] Each of the two or more sub-blanks 101, 102 may be made of a different material. For example, the sub-blank 101 designed to be located outside the U-shaped cross section (relative to the central free space 150) may be made of UHSS (e.g., boron steel, such as 22MnB5 or the like), and the sub-blank 102 designed to be located inside the U-shaped cross section may be made of a more ductile steel (e.g., 1000 or similar).

[0107] is a ductility ratio Steel material is much higher, and components made of this material can effectively absorb energy during impact. The yield strength of 500 may be 400 MPa or higher, and the ultimate tensile strength may be 550 MPa or higher.

[0108] The composition of 500 is summarized in weight percentage as follows (the rest is iron (Fe) and impurities):

[0109] Maximum carbon (C) content (%): 0.1

[0110] Maximum silicon (Si) content (%): 0.5

[0111] Maximum manganese (Mn) content (%): 1.7

[0112] Maximum phosphorus (P) content (%): 0.03

[0113] Maximum sulfur (S) content (%): 0.025

[0114] Aluminum (Al) content (%): 0.015-0.2

[0115] Maximum titanium (Ti) content (%): 0.09

[0116] Maximum niobium (Nb) content (%): 0.10

[0117] Maximum copper (Cu) content (%): 0.20

[0118] Maximum boron (B) content (%): 0.001

[0119] Maximum chromium (Cr) content (%): 0.20

[0120] The yield strength of 1000 may be 800 MPa or higher, and the ultimate tensile strength may be 1000 MPa or higher. The composition of 1000 is summarized in weight percentage as follows (the rest is iron (Fe) and impurities):

[0121] Maximum carbon (C) content (%): 0.10

[0122] Maximum silicon (Si) content (%): 0.6

[0123] Maximum manganese (Mn) content (%): 1.8

[0124] Maximum phosphorus (P) content (%): 0.03

[0125] Maximum sulfur (S) content (%): 0.01

[0126] Aluminum (Al) content (%): 0.01-0.1

[0127] Maximum titanium (Ti) content (%): 0.05

[0128] Maximum niobium (Nb) content (%): 0.10

[0129] Maximum copper (Cu) content (%): 0.20

[0130] Maximum boron (B) content (%): 0.005

[0131] Maximum chromium (Cr) content (%): 0.20

[0132] In an example, the two sub-blanks 101 , 102 may be joined by spot welding before the forming process.

[0133] exist Figure 4 and Figure 5 In the example of FIG, the two sub-blanks 101, 102 extend along the periphery of the entire main frame 100, but in other examples, the component may include a main frame 100, wherein the sub-blanks do not extend along the entire length of the main frame 100. For example, the main frame 100 may include a first crossbeam 130 (e.g., Figure 1 The first beam 130 is formed by The first blank and The second blank of the main frame 100 is overlapped and defines a U-shaped cross section. Further, the crossbeam can be connected to the rest of the main frame 100 by an additional overlapping area. In addition, the rest of the main frame 100 can be formed by a single sub-blank or by a plurality of sub-blanks.

[0134] Figure 6 Another example of components coupled to a vehicle frame 1000 is schematically shown from a bottom isometric perspective. The illustrated vehicle frame 1000 includes front longitudinal members 31, rear longitudinal members 41, and components of the present disclosure comprising the main frame 100. In other examples, the vehicle frame 1000 may further include the floor structure and side structures or other components of the vehicle.

[0135] As previously disclosed, the main frame 100 can be configured to receive the battery assembly 50. The battery assembly 50 can be received in the central free space of the annular shape. Furthermore, the side members 110, 120 of the main frame 100 can be configured to connect to the front and rear longitudinal members 31, 41 at the front end 200 and rear end 300 of the vehicle frame 1000, respectively. In some examples, the main frame 100 can be welded to the front and rear longitudinal members 31, 41.

[0136] Additionally, the side sills 110, 120 can be configured to connect to side sills (not shown) of the vehicle frame 1000. The connection can be made at various points along the longitudinal direction. In some examples, the connection between the side sills 110, 120 and the side sills occurs at a substantially fore-aft location, i.e., more centrally than the connection to the front and rear side rails 31, 41, respectively.

[0137] Note that areas of the main frame 100 configured to connect to other structural elements of the vehicle frame 1000 may have suitable mechanical properties to achieve a safe and secure connection. These areas may include materials with different mechanical properties than the rest of the main frame 100 (e.g., soft areas or metal patches). Furthermore, specific overlapping areas of the sub-blanks may be formed in these areas to increase local thickness.

[0138] Although not in Figure 6100, but the assembly may include one or more additional components attached to the main frame 100. The additional components may be covers, panels, or structural components similar to the main frame 100.

[0139] Figure 7 The blank 10 according to another example is schematically shown before being formed into an annular main frame. The blank 10 may include at least two sub-blanks, the at least two sub-blanks forming one or more overlapping regions, and the one or more overlapping regions are formed by partially overlapping the two sub-blanks. Figure 7 In the example shown, a single blank 10 includes eight sub-blanks 11, 12, 13, 14, 15, 16, 17, 18. In this example, each sub-blank 11, 12, 13, 14, 15, 16, 17, 18 can be formed from the same material (eg, boron steel, etc.). 2000 or 1500, but in other examples, the sub-blanks may be formed from different materials so that the mechanical properties after forming the main frame may be significantly different.

[0140] Furthermore, in other examples, one or more sub-blanks may be formed from a material having a substantially uniform composition, but may be subjected to heat treatment such that, after forming, the mechanical properties of the corresponding component are not uniform. Thus, a sub-blank may include a first portion having higher mechanical properties than a second portion. Furthermore, the first portion may be configured to withstand high impact loads, and the second portion may include a connection point to the main frame 100 or other components of the vehicle frame.

[0141] Furthermore, Figure 7 A single blank 10 is shown including multiple overlap regions 19. The overlap regions 19 may be located where the main frame 100 requires higher mechanical properties to withstand the loads acting thereon. The length and shape of the overlap regions 19 may be designed so as to cover only those locations where high loads are likely to exist. Additionally, the overlap regions 19 may be designed to cover areas where the cross section transitions from one member to another, such as between a cross member and a side member. Figure 7 In the example shown, the overlap region 19 represents the transition between the side members and the cross members, for example, the transition between the cross member 14 and the side members 15, 13. Furthermore, the shape and size of the overlap region 19 can be designed to improve the main frame 100 (see Figure 1 )'s overall strength without causing excessive weight.

[0142] In an example, the first sub-blank may extend onto the second sub-blank by a length between 2 cm and 30 cm.

[0143] Also by appropriately selecting and providing the overlap regions 19, internal bracing between the main frame 100 and other components of the vehicle may be eliminated or reduced.

[0144] In addition, the overlapping area 19 can improve the rigidity of the connection between the main frame 100 and other components (such as the battery module fixing portion). Figure 7 In the example of FIG, the side member 12 includes a connection point 125 for a battery module fastening portion, which is at least partially located in the overlapping area 19. In addition, the side members 11, 12 include a connection point 115 for a chassis fastening portion, which is at least partially located in the overlapping area 19.

[0145] Further, the overlap region 19 may be designed to provide improved NVH (noise, vibration and harshness) performance, particularly around the main frame connection points 115 to the front and rear chassis.

[0146] Note that the connection points 125, 115 are shown on only one side of the single blank 10. The connection points 125, 115 may be arranged symmetrically on the single blank 10 relative to the central longitudinal axis 1. In other examples, the connection points 125, 115 may not be symmetrical relative to the central longitudinal axis 1.

[0147] In other examples, patches (not shown) may be included on the sub-blank by overlapping the patches to the sub-blank and spot welding them. As previously mentioned, more than one patch may be welded to a single blank 10 prior to stamping.

[0148] Furthermore, the thickness of at least some of the sub-blanks 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 may be between 0.8 mm and 3 mm, specifically between 1 mm and 2.5 mm.

[0149] In the example, other suitable steels can be used, any steel suitable for hot stamping or cold stamping. In the example, the blank or sub-blank can be made of dual phase steel (DP steel), such as side beams and / or cross beams. DP steel is a high strength steel with a ferrite-martensite microstructure, which is obtained by quenching the component from a temperature above Ac1 but below Ac3. DP steel includes a microstructure consisting of a soft ferrite matrix containing martensite islands. Components made of DP steel can have an ultimate tensile strength of less than 900 MPa, relatively good fatigue resistance and high strain rate sensitivity, i.e. the faster it collapses in the event of an impact, the more energy it absorbs.

[0150] Further, other steels showing high formability, possibly in combination with high strength, may also be used to manufacture (a portion of) the main frame 110 by a cold forming process. The resulting components, such as side members and / or cross members, may provide additional weight savings compared to components made from DP steel having similar mechanical properties. Steel is commercially available from ArcelorMittal.

[0151] In some examples, the main frame 110 may be composed of For example, the main frame 110 can be made of 1180 (HF1180Y850), which has a tensile strength of 1180 MPa to 1330 MPa. In other examples, the main frame 110 can be made of S1270, which has a tensile strength of 1270 MPa to 1400 MPa. In another example, the main frame 110 may include 1180 made of components and In addition, the main frame 110 is made of The fabricated components can be welded together using conventional welding techniques (eg, spot welding).

[0152] The composition of 1180 is summarized in weight percentage as follows (the rest is iron (Fe) and impurities):

[0153] Maximum carbon (C) content (%): 0.23

[0154] Maximum silicon (Si) content (%): 2.0

[0155] Maximum manganese (Mn) content (%): 2.9

[0156] Maximum phosphorus (P) content (%): 0.040

[0157] Maximum sulfur (S) content (%): 0.010

[0158] Aluminum (Al) content (%): 0.015-1.0

[0159] Maximum titanium plus niobium (Ti+Nb) content (%): 0.15

[0160] Maximum niobium (Nb) content (%): 0.10

[0161] Maximum copper (Cu) content (%): 0.20

[0162] Maximum boron (B) content (%): 0.005

[0163] Maximum chromium plus molybdenum (Cr+Mo) content (%): 0.60

[0164] The composition of S1270 is summarized as follows in weight percentage (the rest is iron (Fe) and impurities):

[0165] Maximum carbon (C) content (%): 0.21

[0166] Maximum silicon (Si) content (%): 1.5

[0167] Maximum manganese (Mn) content (%): 4.1

[0168] Maximum phosphorus (P) content (%): 0.04

[0169] Maximum sulfur (S) content (%): 0.01

[0170] Aluminum (Al) content (%): 0.015-1.0

[0171] Maximum titanium plus niobium (Ti+Nb) content (%): 0.15

[0172] Maximum niobium (Nb) content (%): 0.10

[0173] Maximum copper (Cu) content (%): 0.2

[0174] Maximum chromium plus molybdenum (Cr+Mo) content (%): 0.6

[0175] Steels suitable for hot and cold forming in combination with other materials may also be used to fabricate at least some components of the disclosed main frame 110 .

[0176] In another aspect of the present disclosure, a method 400 is provided for manufacturing a component of a vehicle frame including a main frame 100. The main frame 100 substantially defines a closed annular shape and includes first and second side rails 110, 120 and first and second cross rails 130, 140.

[0177] exist Figure 8 An example of a method 400 is schematically shown in FIG. Method 400 includes, at block 401, providing a single blank 10. Method 400 further includes, at block 402, at least partially heating the single blank 10 to a temperature above the Ac3 austenitizing temperature. Furthermore, method 400 includes, at block 403, press-hardening the heated single blank 10 to form a component.

[0178] In the example, as previously mentioned, the single blank 10 is made of hardenable steel and the soft zone can be created during controlled cooling within the mold of the formed part or after the formed part has been heated.

[0179] In some examples, the single blank 10 of the method 400 can include at least two sub-blanks 11, 12, 13, 14, 15, 16, 17, 18, and the method 400 can further include joining the sub-blanks 11, 12, 13, 14, 15, 16, 17, 18 to each other. The step of joining the sub-blanks 11, 12, 13, 14, 15, 16, 17, 18 includes forming one or more overlapping regions 19 by partially overlapping the two sub-blanks 11, 12, 13, 14, 15, 16, 17, 18.

[0180] In an example, the single blank 10 of the method 400 may include a tailor-welded blank including at least two sub-blanks 11 , 12 , 13 , 14 , 15 , 16 .

[0181] The single blank 10 may be made from any type of hardenable steel, particularly boron steel, as previously discussed with respect to the main frame 100 .

[0182] The heating step 402 of the method 400 may include substantially uniformly heating the individual blanks 10 to above an austenitizing temperature and subsequently cooling specifically portions of the individual blanks 10 to below the austenitizing temperature.

[0183] In an example, a single blank 10 is heated to above Ac3 and a portion of the single blank 10 is cooled to a temperature below Ac3, or even below Ac1, before deforming the blank 10. Other portions may be kept above Ac3 until the blank 10 is deformed, or may be temporarily cooled and then heated again to above Ac3.

[0184] In some examples, different portions of the blank 10 may have different temperatures when the blank 10 is positioned in the pressing tool, while the temperature within those locations is substantially constant.

[0185] Thus, different temperatures may lead to different microstructural or strength properties being set in the corresponding parts of the main frame 100 , in particular during the subsequent rapid cooling (“quenching”), for example in the mold of a pressing tool.

[0186] In an example, the composite blank 10 is formed during the press-hardening step 403 to form the main frame 100 and simultaneously quenched to below 400° C., or specifically below 300° C.

[0187] In some examples, method 400 may further include the step of bake-hardening component 100. During bake-hardening, the component may be heated between 170 degrees Celsius and 200 degrees Celsius, and more specifically, at approximately 170 degrees Celsius, for approximately 20 minutes.

[0188] Although only a few examples are disclosed herein, other alternatives, modifications, uses, and / or their equivalents are possible. In addition, all possible combinations of the described examples are contemplated. Therefore, the scope of this disclosure should not be limited by the specific examples, but should be determined solely by a reasonable reading of the appended claims.

Claims

1. A component for a vehicle frame, comprising: a main frame extending from a front end to a rear end along a longitudinal direction of the vehicle frame, wherein The main frame substantially defines a closed annular shape and is configured to receive a battery assembly in a central free space of the closed annular shape, and wherein The main frame includes a first side beam and a second side beam extending substantially along the longitudinal direction of the vehicle frame, and a first cross beam and a second cross beam extending substantially horizontally and perpendicularly to the longitudinal direction of the vehicle frame, wherein The main frame is formed by deforming a single blank.

2. The component according to claim 1, wherein The main frame is manufactured by hot stamping.

3. A component according to any one of claims 1 and 2, wherein The single blank comprises at least a first sub-blank, the first sub-blank being joined to a second sub-blank such that the first sub-blank partially overlaps the second blank, thereby forming an overlapping region.

4. The component according to claim 3, wherein The overlap region is located in a portion of the main frame that is configured to be connected to other components of the vehicle frame.

5. A component according to claim 3 or 4, wherein: The length of the first sub-blank extending onto the second sub-blank is at least 1 cm, in particular between 2 cm and 30 cm.

6. A component according to any one of claims 1 to 5, wherein The single blank comprises a tailored welded blank comprising at least two sub-blanks joined to each other edge to edge.

7. A component according to any one of claims 1 to 6, wherein At least a portion of the main frame is made of steel having an ultimate tensile strength higher than 1500 MPa after a press hardening process.

8. A component according to any one of claims 1 to 7, wherein At least a portion of the main frame has a substantially U-shaped cross-section, wherein The U-shape has a bottom wall, a first side wall, a second side wall, a first side flange protruding outward at one end of the first side wall, and a second side flange protruding outward at one end of the second side wall.

9. A component according to any one of claims 1 to 8, wherein The side beam includes a central region between the front end and the rear end, and wherein the central region is configured to be connected to the battery assembly.

10. A component according to any one of claims 1 to 9, wherein The side members are configured to be connected to front and rear side members of the vehicle frame at the front and rear ends, respectively.

11. A component according to any one of claims 1 to 12, wherein Each side member is configured to be connected to a lateral sill of the vehicle frame.

12. A component according to any one of claims 1 to 11, wherein The main frame includes a soft zone having a lower yield strength and / or tensile strength than the remainder of the main frame.

13. A method for manufacturing a component for a vehicle frame, the component comprising a main frame substantially defining a closed annular shape and configured for receiving a battery assembly in a central free space formed within the closed annular shape, and the main frame comprising first and second side beams and first and second cross beams, The method comprises: Provide single blanks; heating the single blank at least partially to above the Ac3 austenitizing temperature; as well as The heated individual blank is press-hardened to form a component according to any one of claims 1 to 13 .

14. The method according to claim 13, wherein: The single blank comprises at least two sub-blanks, and the method comprises joining the sub-blanks to each other before press-hardening.

15. The method according to claim 14, wherein: Joining the sub-blanks includes forming one or more overlapping regions by partially overlapping two sub-blanks.

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