Integral bumper beam assembly for vehicle

Abstract

The present disclosure relates to a method for manufacturing an integral bumper beam assembly for a vehicle. The method includes providing a plurality of blanks, joining the blanks to each other to form a combined blank, and deforming the combined blank to form the unitary bumper beam assembly. The integral bumper beam assembly includes a bumper beam, a pedestrian beam, and at least one bracket connecting the bumper beam to the pedestrian beam. The plurality of blanks includes a bumper beam blank and a pedestrian beam blank, and the joining blank includes forming one or more overlap regions formed by partially overlapping the blanks with each other. The present disclosure also relates to an integral bumper beam assembly obtainable by such a method.

Description

Technical Field

[0001] This application claims the benefit of EP22382650.4 filed on July 7, 2022.

[0002] The present disclosure relates to an integrated bumper beam assembly for a vehicle and a method of manufacturing the integrated bumper beam assembly for a vehicle. Background Art

[0003] Vehicles such as cars incorporate a structural framework designed to withstand all loads that the vehicle may experience during its life. The structural framework is also designed to withstand and absorb impacts in the event of a collision, such as with other cars, obstacles or pedestrians.

[0004] In this sense, the structural framework of a vehicle (eg, an automobile) may include, for example, bumpers, pillars (A-pillars, B-pillars, C-pillars, D-pillars), side impact beams, rockers or sills, hinge struts, and shock absorbers.

[0005] One of the structures that plays a role in vehicle protection in the event of a frontal or rear impact is the bumper beam. A bumper can typically include a bumper beam (i.e., a cross beam made of high-strength material that is the main structural part of the bumper), and a cover and absorber structure (which is typically made of plastic).

[0006] The main function of a bumper beam is to protect the vehicle and its passengers. The bumper beam is an energy absorbing component that protects the vehicle body in the event of a collision. The front bumper beam is usually connected to the front rail via a crash box. Therefore, deformation of the front rail only occurs when the energy absorption capacity of the bumper beam and the crash box is exceeded.

[0007] Additionally, the vehicle may include a lower bumper beam, also known as a pedestrian beam, at the front end. The pedestrian beam may be joined to the bumper beam by vertical brackets to form a bumper beam assembly. While the bumper beam is an energy absorbing component that protects the vehicle body in the event of a collision, the lower bumper beam or pedestrian beam is a component of the bumper beam assembly that is intended to ensure the safety of pedestrians.

[0008] Bumper beams and pedestrian beams have different functionalities; therefore, they are typically made of different materials and may be manufactured differently.

[0009] The upper beam is a component with a desired high stiffness, usually achieved by hot stamping ("press hardening"), the purpose of which is to limit intrusion in the event of an impact of relatively low weight. The pedestrian beam is a member joined to the bumper beam for protecting pedestrians in the event of an impact. The pedestrian beam can therefore be a softer component. Its thickness is usually less than that of the bumper beam and it is usually made of a material suitable for cold stamping.

[0010] Press hardening, also known as hot forming die quenching (HFDQ), typically uses boron steel sheets to produce stamped parts with ultra-high strength steel (UHSS) properties, which have a tensile strength of, for example, 1.500 MPa or 2.000 MPa or even higher. The increase in strength allows the use of thinner gauge material, which results in a weight saving over conventional cold stamped low carbon steel parts. Throughout this disclosure, UHSS can be considered to be a steel with an ultimate tensile strength of 1.000 MPa or higher after the press hardening process.

[0011] 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 in particular between Ac3 and, for example, the evaporation temperature of the blank coating). A furnace system can be used for this purpose. Depending on specific needs, the furnace system can be supplemented with additional heaters, such as induction or infrared. By heating the blank, the strength of the blank is reduced and the deformability is increased, i.e., facilitating the hot stamping process.

[0012] 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 commercially available from ArcelorMittal. (22MnB5).

[0013] 1500P is an example of 22MnB5 steel. The composition of is summarized as follows in weight percentage (the balance is iron (Fe) and impurities):

[0014] Maximum carbon (C) (%): 0.25

[0015] Maximum Silicon (Si) (%): 0.4

[0016] Maximum manganese (Mn) (%): 1.4

[0017] Maximum phosphorus (P) (%): 0.03

[0018] Maximum sulfur (S) (%): 0.01

[0019] Aluminum (Al) (%): 0.01-0.1

[0020] Maximum titanium (Ti) (%): 0.05

[0021] Maximum niobium (Nb) (%): 0.01

[0022] Maximum copper (Cu) (%): 0.20

[0023] Maximum boron (B) (%): 0.005

[0024] Maximum chromium (Cr) (%): 0.35

[0025] 1500P may have, for example, a yield strength of 1.100 MPa and an ultimate tensile strength of 1.500 MPa.

[0026] 2000 is another boron steel with higher strength. The yield strength of 2000 can be 1.400 MPa or higher, and the ultimate tensile strength can be higher than 1.800 MPa. The composition of 2000 is summarized in weight percentage as follows (the balance is iron (Fe) and impurities):

[0027] Maximum carbon (C) (%): 0.36

[0028] Maximum Silicon (Si) (%): 0.8

[0029] Maximum manganese (Mn) (%): 0.8

[0030] Maximum phosphorus (P) (%): 0.03

[0031] Maximum sulfur (S) (%): 0.01

[0032] Aluminum (Al) (%): 0.01-0.06

[0033] Maximum titanium (Ti) (%): 0.07

[0034] Maximum niobium (Nb) (%): 0.07

[0035] Maximum copper (Cu) (%): 0.20

[0036] Maximum boron (B) (%): 0.005

[0037] Maximum chromium (Cr) (%): 0.50

[0038] Maximum Molybdenum (Mb) (%): 0.50

[0039] As mentioned above, hot forming press quenching may also be referred to as "press hardening" and the term "hot stamping" may also be used. These terms are used interchangeably in this disclosure.

[0040] Typical vehicle parts that can be manufactured using the HFDQ method include: door beams, bumper beams, transverse / lateral members, A / B pillar reinforcements, front and rear rails, seat cross members and roof rails.

[0041] Hot forming of boron steels is becoming increasingly popular in the automotive industry due to their superior strength and formability. Many structural components that were traditionally cold formed from mild steels are therefore replaced by hot formed equivalents that offer a significant increase in strength. This allows the material thickness to be reduced (and therefore weight) while maintaining the same strength.

[0042] In order to improve the ductility and energy absorption in specific areas of a component, it is known to introduce softer areas within the same component. This improves the ductility locally while maintaining the required high strength overall. By locally adjusting 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 their overall energy absorption and maintain their structural integrity during a crash situation, and also reduce their overall weight. Such soft areas can also advantageously change the kinematic behavior in the event that the component collapses under impact.

[0043] A known method of producing a region with increased ductility ("soft zone" or "soft zone") in a structural component of a vehicle comprises 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 an austenitizing temperature or higher, by, for example, a furnace system, in order to reduce the strength, i.e., to facilitate the hot stamping process.

[0044] The die elements can be designed to operate at different temperatures so as to have different cooling rates in different areas of the component being formed during the quenching process, thereby producing different material properties in the final product, such as soft areas that typically have lower ultimate tensile strength and lower yield strength, but allow for greater elongation before fracture. For example: one die element can be cooled so as to quench a corresponding area of ​​the manufactured component at a high cooling rate, thereby quickly reducing the temperature of the component and obtaining a hard martensitic microstructure. Another adjacent die element can be heated so as to ensure that the corresponding part of the manufactured component is cooled at a lower cooling rate so as to obtain a softer microstructure, including, for example, bainite, ferrite and / or pearlite. When the component leaves the die, such an area of ​​the component can be maintained at a higher temperature than the rest of the component.

[0045] Other methods for obtaining hot stamped parts with areas of 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. Additional possibilities include the use of seamed blanks and tailored welded blanks (TWB), combining different thicknesses and / or materials in the blank.

[0046] UHSS can exhibit tensile strengths as high as 1.500 MPa, or even 2.000 MPa or more, especially after a press hardening operation. Once hardened, UHSS can have a martensitic microstructure. This microstructure can increase the maximum tensile strength and yield strength per unit weight.

[0047] In addition to the ultra-high strength steels mentioned above, more ductile steels may be used in structural skeleton components where energy absorption is required. These steels can be used in hot stamping processes, but a martensitic microstructure will not be obtained in this process. Examples of suitable more ductile steels include 500, 1000 and CRL-340LA.

[0048] Another material used in hot stamping is 500. 500 is a much more ductile steel material, and these materials can effectively absorb energy during impact. The yield strength of 500 can be 400 MPa or higher and the ultimate tensile strength is 550 MPa or higher.

[0049] The composition of 500 is summarized in weight percentage as follows (the balance is iron (Fe) and impurities):

[0050] Maximum carbon (C) (%): 0.1

[0051] Maximum Silicon (Si) (%): 0.5

[0052] Maximum manganese (Mn) (%): 1.7

[0053] Maximum phosphorus (P) (%): 0.03

[0054] Maximum sulfur (S) (%): 0.025

[0055] Aluminum (Al) (%): 0.015-0.2

[0056] Maximum titanium (Ti) (%): 0.09

[0057] Maximum niobium (Nb) (%): 0.10

[0058] Maximum copper (Cu) (%): 0.20

[0059] Maximum boron (B) (%): 0.001

[0060] Maximum chromium (Cr) (%): 0.20

[0061] and 1500 and Compared with 2000, 1000 is another material used to increase elongation in hot stamping. The yield strength of 1000 may be 800 MPa or higher, and the ultimate tensile strength is 1000 MPa or higher. The composition of 1000 is summarized in weight percentage as follows (the balance is iron (Fe) and impurities):

[0062] Maximum carbon (C) (%): 0.10

[0063] Maximum Silicon (Si) (%): 0.6

[0064] Maximum manganese (Mn) (%): 1.8

[0065] Maximum phosphorus (P) (%): 0.03

[0066] Maximum sulfur (S) (%): 0.01

[0067] Aluminum (Al) (%): 0.01-0.1

[0068] Maximum titanium (Ti) (%): 0.05

[0069] Maximum niobium (Nb) (%): 0.10

[0070] Maximum copper (Cu) (%): 0.20

[0071] Maximum boron (B) (%): 0.005

[0072] Maximum chromium (Cr) (%): 0.20

[0073] Since the requirements for each component are so different, the bumper beam assembly is usually made of several parts. Typically, the bumper beam assembly can be formed by hot stamping a bumper beam blank and cold stamping a pedestrian beam blank. After the corresponding forming process, the beams can be connected to each other by vertical brackets. The brackets can be welded to the bumper beam and the pedestrian beam. Thus, the bumper beam assembly can be formed by welding together, for example, four individual stampings. The welding is usually carried out by metal active gas (MAG).

[0074] One problem that has been encountered is that several welds and seams can lead to vulnerable parts in a crash. Weight, manufacturability and cost are also issues that need to be considered.

[0075] The present disclosure provides examples of systems and methods that at least partially address some of the above-mentioned shortcomings. Summary of the invention

[0076] In a first aspect, a method for manufacturing an integral bumper beam assembly for a vehicle is provided, the method comprising: providing a plurality of blanks; joining the blanks to form a combined blank; deforming the combined blank to form a bumper beam assembly, wherein the bumper beam assembly comprises a bumper beam and a pedestrian beam and at least one bracket connecting the bumper beam to the pedestrian beam.

[0077] Joining the blanks to each other to form a combined blank, and then deforming the combined blank, provides a lightweight and durable bumper beam assembly that is constructed in fewer steps. Joining the blanks together before deforming enables the manufacture of a bumper beam assembly with no or less heat-affected zone, since welding operations after forming are reduced. Less heat-affected zone reduces the risk of cracks in accident situations.

[0078] Herein, the bracket may be considered to be a substantially vertical connector for joining the bumper beam to the pedestrian beam.

[0079] In some examples, blanks of varying material thicknesses and / or grades may be used in order to meet specific strength, intrusion resistance, and energy absorption requirements as well as to optimize weight.

[0080] In some examples, the plurality of blanks include a bumper beam blank, a bracket blank, and a pedestrian beam blank. In some examples, the bumper beam blank may be made of ultra-high strength steel, and the pedestrian beam blank may be made of a material that is more ductile than the bumper beam blank.

[0081] Throughout this disclosure, a bumper beam blank may be considered to be a blank that is subsequently deformed to form a bumper beam. Similarly, a pedestrian beam blank and a bracket blank may be considered to be a blank that is subsequently deformed to form a pedestrian beam and a bracket, respectively.

[0082] The bumper beam blank may be a blank formed of one or more sub-blanks. The pedestrian beam blank may be a blank formed of one or more sub-blanks. The bumper beam blank and the pedestrian beam blank may be joined together by at least one bracket.

[0083] In some examples, deforming the composite blank to form the integral bumper beam assembly includes hot stamping the composite blank. Hot stamping is a process that allows the ultra-high strength steel to deform appropriately to form the complex final structure of the integral bumper beam assembly.

[0084] In some examples, deforming the combined blank can be done in a single operation. This can allow the strength of the bumper beam assembly to be increased while reducing the thickness of the blank and reducing the weak points of the final assembly. The combined blank can be formed prior to the deforming operation. The hazards caused by the joints are eliminated, thereby reducing the risk of cracks in the integral bumper beam assembly in the event of a collision.

[0085] In another aspect, there is provided an integral bumper beam assembly obtained by a method according to any example described herein. BRIEF DESCRIPTION OF THE DRAWINGS

[0086] Non-limiting examples of the present disclosure will now be described with reference to the accompanying drawings, in which:

[0087] Figure 1 An example of a bumper beam assembly for a vehicle according to the prior art is shown;

[0088] Figure 2 An example of an integral bumper beam assembly for a vehicle is shown;

[0089] Figure 3 An example of a plurality of blanks prior to being joined to form a combined blank is shown;

[0090] Figure 4 An example of a schematic diagram of a combined blank formed from four joined blanks is shown;

[0091] Figure 5A An example of a one-piece bumper beam assembly for a vehicle having a single bracket connecting the bumper beam to a pedestrian beam is shown;

[0092] Figure 5B Another example of an integral bumper beam assembly for a vehicle is shown having two brackets connecting the bumper beam to a pedestrian beam;

[0093] Figure 6 shows an example of an enlarged view of a joint blank after deformation in an integral bumper beam assembly of a vehicle;

[0094] Figure 7 Examples of alternative cross sections for bumper beams are shown;

[0095] Figure 8 An example of a side view of an integral bumper beam assembly is shown;

[0096] Fig.9A An example of an integral bumper beam assembly for a vehicle including a support for an auxiliary system is shown;

[0097] Fig. 9B An example of a support for an auxiliary system in an integral bumper beam assembly is shown; and

[0098] Fig.10 is a flow chart of a method for manufacturing a one-piece bumper beam assembly for a vehicle.

[0099] The drawings relate to example implementations and may be used merely to aid in understanding the claimed subject matter and are not intended to limit the same in any sense. DETAILED DESCRIPTION

[0100] In these figures, the same reference numerals are used to denote matching elements.

[0101] Figure 1 A prior art bumper beam assembly is shown. The bumper beam assembly comprises a bumper beam 10, a pedestrian beam 20 and two connecting brackets 30. The bumper beam assembly is made of four separate components that are subsequently welded together. The bumper beam 10 can be considered as the main component of the bumper designed to absorb impacts. The bumper beam 10 can be made of UHSS in a hot stamping process. In an example, the bumper beam 10 can include one or more softer areas, i.e., areas with lower mechanical strength than other parts of the bumper beam, to increase energy absorption and control the kinematics of deformation in the event of an impact.

[0102] The pedestrian beam 20 generally does not require the same strength and stiffness and may be made by cold forming, i.e. for example, dual phase steel or complex phase steel may be used. The pedestrian beam 20 is generally configured to avoid or reduce lower leg injuries in the event of a collision with a pedestrian.

[0103] A grille (not shown), ie a cover for an opening in the vehicle for an air inlet or outlet, may typically be arranged between the bumper beam 10 and the pedestrian beam 20. The arrangement of the bracket 30 may be adapted to the desired shape of the grille.

[0104] Figure 2 An integrated bumper beam assembly 100 of a vehicle according to an example of the present disclosure is schematically shown. The integrated bumper beam assembly 100 includes a bumper beam 10, a pedestrian beam 20, and at least one connecting bracket 30. The bumper beam 10 and the pedestrian beam 20 are connected to the vehicle through a crash box 40.

[0105] In this example, the crash box 40 is provided for the bumper beam 10 and the pedestrian beam 20. In other examples, the crash box 40 is provided only for the bumper beam 10. The crash box 40 of the bumper beam 10 may be connected to a rail of a vehicle frame.

[0106] In some examples, the integrated bumper beam assembly 100 may define a front impact management system for a vehicle, ie, the assembly may be disposed at a front side of the vehicle and connected to a front rail.

[0107] The integral bumper beam assembly 100 may be formed from multiple blanks in a single forming process. Figure 3As schematically shown in FIG. 1 , the integrated bumper beam assembly 100 may be made of three blanks, a first blank 1, a second blank 2, and a third blank 3, wherein the first blank 1 may be a bumper beam blank 1, the second blank 2 may be a pedestrian beam blank 2, and the third blank 3 may be a bracket blank 3. The bumper beam blank 1 may be joined to the bracket blank 3, and the bracket blank 3 may be joined to the pedestrian beam blank 2. The combined blank 4 including the three blanks 1, 2, 3 may thus be formed as shown in FIG. Figure 4 The blanks can be welded to each other, for example, by laser welding or spot welding. In a subsequent step, the combined blank 4 can be heated and deformed.

[0108] In other examples, the bumper beam assembly 100 may be made from a first blank 1 and a second blank 2, where the first blank 1 may be a bumper beam blank 1 and the second blank 2 may be a pedestrian beam blank 2. In these examples, the first and / or second blanks 1, 2 may include a portion of a blank for forming the bracket 30.

[0109] In some embodiments, the bumper beam blank 1 can be formed from a single blank. In other examples, the bumper beam blank 1 can be formed from a plurality of blanks or sub-blanks, for example, having different thicknesses and / or different materials. In these examples, the plurality of blanks forming the bumper beam blank 1 can be tailored welded blanks (TWBs). The TWB can be formed by joining the sub-blanks by edge-to-edge welding, wherein the welding can include laser welding. In other examples, the plurality of blanks forming the bumper beam blank 1 can be joined by forming one or more overlapping regions, wherein the one or more overlapping regions are formed by partially overlapping the blanks with each other. In these cases, any of laser welding, arc welding, or spot welding can be used.

[0110] In some examples, the bumper beam blank 1 may include at least one vertical upright portion to form (a portion of) the bracket 30. The vertical upright portion may have a width sufficient to ensure a functional and secure engagement between the bumper beam blank 1 and the pedestrian beam blank 2.

[0111] In some embodiments, the pedestrian beam blank 2 is formed from a single blank. In other examples, the pedestrian beam blank 2 is formed from a plurality of blanks, such as a welded blank including sub-blanks of different thicknesses and / or different materials.

[0112] In some examples, the pedestrian beam blank 2 may include at least one vertical upright portion. The vertical upright portion may have a width sufficient to ensure a functional and safe joint between the bumper beam blank 1 and the pedestrian beam blank 2, for example 10-15 cm.

[0113] like Figure 4As schematically shown in FIG. 1 , the blanks forming the integral bumper beam assembly 100 may be joined to form a combined blank 4. In one example, the combined blank 4 may be formed by joining the bumper beam blank 1 to the pedestrian beam blank 2 by at least a bracket blank 3. The bracket blank 3 may serve as a substantially vertical connector between the bumper beam blank 1 and the pedestrian beam blank 2. The width W1 of the bracket blank 3 may be, for example, 8-20 cm, in particular 5-15 cm.

[0114] In some examples, joining the blanks includes joining a first end of the bracket blank 3 to the bumper beam blank 1 and joining a second end of the bracket blank 3 to the pedestrian beam blank 2. The blanks may be welded to each other, for example, by laser welding (particularly edge to edge) or spot welding. Figure 4 5 where the blanks are joined. In some examples, the width W2 of the overlap region 5 between the bracket blank and the bumper beam blank (i.e., the extent to which the bracket blank extends into the bumper beam blank) can be, for example, 2 cm-10 cm. Suitable dimensions for the overlap region can be selected taking into account weldability and strength and stiffness requirements. A larger overlap region means an increase in thickness over a larger area, and therefore an increase in local strength and stiffness in the bumper beam.

[0115] As can be seen in some of the examples below, the overlap region may be such that it covers a portion of the side wall of the U-shape formed during the hot stamping process or the entire height of the side wall.

[0116] Similarly, an overlap region may be formed between the bracket blank and the pedestrian beam blank.

[0117] Thus, one or more overlapping regions can be formed in the transition region between the bumper beam and the support beam and / or between the pedestrian beam and the support beam in order to strengthen these regions. One or more overlapping regions can be formed in the horizontal portion of the bumper beam and / or in the horizontal portion of the pedestrian beam. The thickness obtained by the overlapping regions leads to an increase in strength and stiffness in the transition region, resulting in a more resistant bumper beam assembly.

[0118] In some examples, the bracket blank 3 may be joined to the bumper beam blank 1 at the open side of the hat-shaped cross-section. In other examples, the bracket blank 3 may be joined to the pedestrian beam blank 2 at the protruding portion of the hat-shaped cross-section.

[0119] like Figure 5A As shown, in some examples, the integrated bumper beam assembly 100 includes one bracket 30 b connecting the bumper beam 10 to the pedestrian beam 20 . In other examples, the integrated bumper beam assembly 100 includes two or more brackets 30 connecting the bumper beam 10 to the pedestrian beam 20 . Figure 5BAn example of an integral bumper beam assembly 100 is shown that includes two brackets 30a, 30c connecting the bumper beam 10 to the pedestrian beam 20. In other examples, the integral bumper beam assembly 100 includes three brackets connecting the bumper beam 10 to the pedestrian beam 20. A variety of possibilities are possible depending on the design of the integral bumper beam assembly and the vehicle.

[0120] In another example (not shown), the combined blank 4 can be formed by directly joining a bumper beam blank 1 including one or more vertical portions to a pedestrian beam blank 2, by joining a perpendicular vertical portion of the bumper beam blank 1 to the pedestrian beam blank 2. In another example, the combined blank 4 can be formed by directly joining a bumper beam blank 1 to a pedestrian beam blank 2, by directly joining at least one perpendicular vertical portion of the pedestrian beam blank 2 to the bumper beam blank 1. When forming the combined blank in this manner, fewer joining steps may be required.

[0121] In some examples, the multiple blanks forming the combined blank 4 may be made of different materials. At least some of the blanks may be made of ultra-high strength steel (UHSS). In some examples, the bumper beam blank 1 may be made of ultra-high strength steel. Boron steel, such as 22MnB5, or other steel compositions mentioned or mentioned above may be suitable UHSS. These blanks, such as boron steel blanks, may include an aluminum silicon coating or a zinc coating.

[0122] The multiple blanks forming the combined blank 4 may include different materials and / or thicknesses. In some examples, the pedestrian beam blank 2 may be made of a more ductile material than the bumper beam blank 1. For example, Blanks (e.g. 1500 or 2000) and A blank or a portion of a blank (eg 500 or 1000) can be used in the blanks for forming the combined blank 4. The use of these types of materials during hot forming and subsequent quenching results in The structure of the component (for example, in the bumper beam blank) is mainly martensitic and The ferrite-pearlite structure is predominant in the component (eg, in the pedestrian beam blank and / or the bracket blank). According to these aspects, the performance of the integral bumper beam assembly 100 can be adjusted.

[0123] In some examples, according to any of the examples described herein, the integral bumper beam assembly 100 can include regions having different ultimate tensile strengths. In some of these examples, the regions having different ultimate tensile strengths can have different microstructures.

[0124] In some examples, at least one of the blanks 1, 2, 3 may include regions with different ultimate tensile strengths. The blank may be made of two different materials with different tensile strengths. Therefore, the ductility of the region with lower tensile strength is higher, thereby increasing the energy absorption in a collision.

[0125] Different microstructures can be produced in the hot-formed bumper beam assembly. These different microstructures can be produced by heating the combined blank 4 above the austenitizing temperature and then controlling the cooling of the combined blank 4 during the process of forming the combined blank 4 to form the bumper beam assembly. The cooling of different regions of the combined blank 4 can be controlled by providing a heater for the region of the forming tool. Therefore, the integral bumper beam assembly 100 includes a region having a mainly martensitic structure and a region including ferrite, pearlite or bainite or a mixture thereof. Alternatively, different microstructures can be produced by partially heating a portion of the integral bumper beam assembly, for example using a laser beam, which has been press-hardened to change the structure that is mainly martensitic to a structure that includes ferrite and / or pearlite and / or bainite and / or tempered martensite and a mixture thereof. The tensile strength of the mainly martensitic structure may be higher than 1400 MPa, in particular higher than 1500 MPa, whereas the tensile strength of the regions with lower strength may be lower than 1000 MPa, in particular lower than 800 MPa, for example between 800 MPa and 500 MPa.

[0126] Therefore, the bumper beam blank 1 may be made of a material that can effectively absorb energy during an impact. In some examples, the bumper beam blank 1 may be made of at least ultra-high strength steel.

[0127] The thickness of the bumper beam 10 may be 1.5-3 mm. The bumper beam 10 may have an ultimate tensile strength of 1500-2000 MPa.

[0128] The pedestrian beam blank 2 may be made of a different material than the bumper beam blank 1. The pedestrian beam blank 2 may be made of a material and thickness that meet pedestrian protection requirements. The thickness of the pedestrian beam 20 may be less than the thickness of the bumper beam 10. In one example, at least a portion of the pedestrian beam blank 2 is made of a more ductile material than the bumper beam blank 1.

[0129] The thickness of the pedestrian beam 20 may be 1-2 mm. The pedestrian beam 20 may have an ultimate tensile strength of 500-1000 MPa.

[0130] The bracket blank 3 can be made of a material that is more ductile than the bumper beam blank 2. In this way, the bracket 30 can accurately control the deformation in the collision. In other examples, the material of the bracket blank 3 can be the same as the material of the bumper beam blank 1.

[0131] In other examples, the bracket 30 may be made of the same material as the pedestrian beam 20. The thickness of the bracket 30 may be 1.5-3 mm. The bracket 30 may have an ultimate tensile strength of 500-1000 MPa.

[0132] In some examples, joining the blanks to each other includes welding the blanks to each other. In some examples, the blanks can be welded by spot welding and / or laser welding. Since the blanks are substantially flat when joined, joining the blanks before deformation can make joining easier. Welding the blanks by laser and / or spot welding before the deformation process can be effective and accurate.

[0133] Figure 6 An example of a deformed joined blank is schematically shown. In this example, the bracket blank 3 can be joined to the bumper beam blank 1 and the pedestrian beam blank 2 by overlapping one blank with the other and using spot welding. In some examples, the overlap area 5 between the bracket blank and the bumper beam blank and the pedestrian beam blank can have a width of 2 cm-10 cm.

[0134] In other examples, joining the blanks to each other may include forming one or more overlapping regions formed by partially overlapping the blanks to each other. In other examples, the one or more overlapping regions may be formed by partially overlapping the bracket blank 3 with the bumper beam blank 1 and / or with the pedestrian beam blank 2. This may be accomplished by laser or spot welding.

[0135] Joining the blanks may result in welds or spots, critical areas that may be susceptible to rupture in the event of a car crash. The deformation after joining can ensure that there are no welds or spots between the blanks, thereby providing a more resistant integral bumper beam assembly 100. The hazards caused by such welds or spots disappear in the integral bumper beam assembly 100, thereby reducing the risk of rupture in the integral bumper beam assembly 100 in the event of a crash.

[0136] Deforming the unitized blank 4 to form the integral bumper beam assembly 100 may include hot forming or hot stamping the unitized blank 4 .

[0137] In some examples, hot forming may include heating the combined blank to above the austenitizing temperature and then forming the combined blank to form an integral bumper beam assembly. In some examples, forming may include two or more forming steps. These forming steps may include, for example, forming, trimming or cutting, and may be performed in a single multi-stage press. Examples of multi-stage presses are known from, for example, US 9,492,859 B2 and WO 2016142367 A1.

[0138] Deformation may include hot forming, i.e., heating the combined blank in an oven that may be above the austenitizing temperature, in particular above Ac3. After heating in the oven, the combined blank 4 may be transferred to a press, where the combined blank 4 is deformed to obtain the final shape of the integral bumper beam assembly 100. Quenching is performed during and immediately after forming. In particular, quenching may include cooling above a critical cooling rate, thereby obtaining a martensitic microstructure. In some examples, quenching may be avoided in selected portions of the bumper beam assembly.

[0139] In some examples, deformation is accomplished in a single operation.Deforming the combined blank 4 may provide a unitary bumper beam assembly 100 having improved crash resistance and produced with fewer processes.

[0140] In some examples, deforming the combined blank 4 to form the integral bumper beam assembly 100 includes providing the bumper beam 10 and the pedestrian beam 20 with a hat-shaped cross-section to better support bending loads.

[0141] In some examples, the hat-shaped cross-section of the pedestrian beam 20 may be open on a first side, and the hat-shaped cross-section of the bumper beam 10 may be open on a second side, such as Figure 5A and 5B In other examples, the hat-shaped cross-section of the pedestrian beam 20 may be open on the first side, and the hat-shaped cross-section of the bumper beam 10 may also be open on the first side, such as Figure 7 At least one bracket 30 may connect the bumper beam 10 to the pedestrian beam 20 .

[0142] Figure 8 A side view of the integrated bumper beam assembly 100 is shown, wherein the connection of the bumper beam 10 and the pedestrian beam 20 formed by the bracket 30 can be further understood.

[0143] Fig.9A Another example of a bumper beam assembly 100 is schematically shown. Fig.9A In the example of FIG. 1 , the integrated bumper beam assembly 100 may include a support member 60 for an auxiliary system. Fig.9AIn the example of , two supports 60 are included. The size and position of the supports may vary depending on the specific requirements of the auxiliary system. The auxiliary system may include one or more sensors, such as proximity sensors for assisting during vehicle parking. The support 60 may be joined to the bumper beam blank before deforming the combined blank, i.e. it may form part of the combined blank 4 and the bumper beam assembly is again formed in a single deformation process and specifically in a single forming step, such as by hot stamping. The addition of the auxiliary system may be ensured without adding welds or points to the integral bumper beam assembly 100, which may be at risk of fracture in the event of an impact. Unnecessary critical areas may be avoided.

[0144] In some examples, the support member 60 for the auxiliary system may include a thickness of 1.5-3 mm. In some examples, the support member 60 for the auxiliary system may have an ultimate tensile strength of 500-1500 MPa. In other examples, the ultimate tensile strength of the support member 60 for the auxiliary system may be 500-1000 MPa.

[0145] The blank for forming the support member 60 can be joined to the bumper beam blank by laser welding (e.g., edge-to-edge welding). Fig. 9B As shown, the blank for the support member 60 may be joined to the blank of the bumper beam by overlapping one blank with the other and using spot welding.

[0146] Fig.10 A flow chart showing a method for manufacturing an integrated bumper beam assembly for a vehicle 200. The method includes providing a plurality of blanks 201; joining the blanks to each other to form a combined blank 202; and deforming the combined blanks to form an integrated bumper beam assembly 203.

[0147] In some examples, providing the plurality of blanks 201 may include providing a bumper beam blank 1, a pedestrian beam blank 2, and a bracket blank 3. In some examples, the plurality of blanks forming the combined blank 4 may be made of different materials. In some examples, the bumper beam blank may be made of ultra-high strength steel, and the pedestrian beam blank may be made of a material that is more ductile than the bumper beam blank.

[0148] In some examples, joining the blanks to each other to form the combined blank 202 may include welding the blanks to each other. The blanks may be welded by spot welding and / or laser welding.

[0149] Deforming the combined blank to form the integral bumper beam assembly 203 may include hot forming or hot stamping the combined blank. Different microstructures may be produced in the hot formed bumper beam assembly. These different microstructures may be produced by heating the combined blank above the austenitizing temperature. In some examples, during and after forming, quenching may be performed. Quenching may include cooling above a critical cooling rate to obtain a martensitic microstructure.

[0150] In some examples, different microstructures may be achieved by heating the combined blank above the austenitizing temperature and then controlling cooling of the combined blank during forming the combined blank to form the bumper beam assembly. In some examples, quenching may be avoided in selected portions of the integral bumper beam assembly.

[0151] In some examples, deforming the combined blank to form the integrated bumper beam assembly 203 can be done in a single operation. The integrated bumper beam assembly 100 formed by deforming the combined blank 203 includes a bumper beam 10, a pedestrian beam 20, and at least one bracket 30 connecting the bumper beam to the pedestrian beam.

[0152] For reasons of completeness, various aspects of the disclosure are set forth in the following numbered clauses:

[0153] Clause 1. A method for manufacturing an integral bumper beam assembly (100) for a vehicle, comprising:

[0154] Providing a plurality of blanks (1, 2, 3);

[0155] joining the blanks to form a combined blank (4);

[0156] The combined blank (4) is deformed to form the integrated bumper beam assembly (100), wherein the integrated bumper beam assembly (100) includes a bumper beam (10), a pedestrian beam (20), and at least one bracket (30) connecting the bumper beam to the pedestrian beam.

[0157] Clause 2. The method for manufacturing an integral bumper beam assembly (100) according to clause 1, wherein joining the blanks comprises welding the blanks to each other.

[0158] Clause 3. The method for manufacturing a one-piece bumper beam assembly (100) according to Clause 2, wherein the welding comprises resistance spot welding and / or laser welding.

[0159] Clause 4. A method for manufacturing an integral bumper beam assembly (100) according to any one of clauses 1-3, wherein deforming the integral blank (4) to form the integral bumper beam assembly (100) includes hot stamping the integral blank (4).

[0160] Clause 5. The method for manufacturing a one-piece bumper beam assembly (100) according to any one of clauses 1 to 4, wherein the deforming is performed in a single operation.

[0161] Clause 6. The method for manufacturing an integral bumper beam assembly (100) according to any one of clauses 1 to 4, wherein the deformation is performed in more than one operation.

[0162] Clause 7. A method for manufacturing an integral bumper beam assembly (100) according to any one of clauses 1-6, wherein the integral bumper beam assembly (100) includes two or more brackets (30) connecting the bumper beam (10) to the pedestrian beam (20).

[0163] Clause 8. The method according to any one of clauses 1-7, wherein the plurality of blanks comprises a bumper beam blank (1) and a pedestrian beam blank (2).

[0164] Clause 9. The method of clause 8, wherein the bumper beam blank (1) is directly joined to the pedestrian beam blank (2).

[0165] Clause 10. The method of clause 8, wherein the plurality of blanks include a bumper beam blank (1), a bracket blank (3), and a pedestrian beam blank (2).

[0166] Clause 11. The method of any one of Clauses 1-10, wherein joining the blanks comprises forming one or more overlapping regions formed by partially overlapping the blanks with each other.

[0167] Clause 12. The method according to clause 11, wherein the one or more overlapping regions are formed by partially overlapping the bracket blank with the bumper beam blank (1) and / or the pedestrian beam blank (2).

[0168] Clause 13. The method according to any one of clauses 1 to 12, wherein the thickness of the pedestrian beam (20) is less than the thickness of the bumper beam (10).

[0169] Clause 14. The method of clause 8, wherein at least a portion of the pedestrian beam blank (2) is made of a more ductile material than the bumper beam blank (1).

[0170] Clause 15. The method according to clause 8, wherein the bumper beam blank (1) is made of ultra-high strength steel.

[0171] Clause 16. The method according to any one of clauses 1 to 15, wherein the bumper beam (10) has an ultimate tensile strength of 1.200 MPa to 2.200 MPa, in particular 1400 to 2000 MPa.

[0172] Clause 17. The method according to any one of clauses 1 to 16, wherein the pedestrian beam (20) has an ultimate tensile strength of 500-1000 MPa, in particular 500-800 MPa.

[0173] Clause 18. The method of any one of clauses 1-17, wherein the integral bumper beam assembly (100) includes a support (60) for an auxiliary system, and optionally, wherein the auxiliary system includes one or more sensors.

[0174] Clause 19. The method according to clause 18, wherein the support (60) for the auxiliary system comprises a thickness of 1.5-3 mm.

[0175] Clause 20. The method according to clause 19, wherein the support (60) for the auxiliary system has an ultimate tensile strength of 500-1500 MPa, in particular 500-1.000 MPa.

[0176] Clause 21. The method of any one of clauses 1-20, wherein deforming the combined blank (4) to form the integral bumper beam assembly (100) includes providing the bumper beam (10) and the pedestrian beam (20) with a hat-shaped cross-section.

[0177] Clause 22. A method according to clause 21, wherein the hat-shaped cross-section of the pedestrian beam (20) is open on a first side, and the hat-shaped cross-section of the bumper beam (10) is open on a second side, and at least one bracket connects the bumper beam (10) to the pedestrian beam (20).

[0178] Clause 23. A method according to clause 21, wherein the hat-shaped cross-section of the pedestrian beam (20) is open on a first side, and wherein the hat-shaped cross-section of the bumper beam (10) is open on the first side, and at least one bracket (30) connects the bumper beam (10) to the pedestrian beam (20).

[0179] Clause 24. The method according to any one of clauses 1 to 22, wherein the deforming is performed in a multi-step press.

[0180] Clause 25. An integral bumper beam assembly obtainable by a method according to any one of clauses 1-24.

[0181] Clause 26. The integrated bumper beam assembly of Clause 25, wherein the integrated bumper beam assembly is a front bumper beam assembly.

[0182] Clause 27. A vehicle comprising the integral bumper beam assembly of Clause 26.

[0183] Although only a plurality of examples are disclosed herein, other replacements, modifications, uses and / or their equivalents are possible. In addition, all possible combinations of the described examples are also contemplated. Therefore, the scope of the present disclosure should not be limited by the specific examples, but should only be determined by a reasonable reading of the appended claims.

Claims

1. A method for manufacturing an integral bumper beam assembly (100) for a vehicle, comprising: Providing a plurality of blanks (1, 2, 3); joining the blanks to form a combined blank (4); deforming the combined blank (4) to form the integrated bumper beam assembly (100), wherein the integrated bumper beam assembly (100) includes a bumper beam (10), a pedestrian beam (20), and at least one bracket (30) connecting the bumper beam to the pedestrian beam, The plurality of blanks include a bumper beam blank (1) and a pedestrian beam blank (2), and Wherein joining the blanks comprises forming one or more overlapping regions, wherein the overlapping regions are formed by partially overlapping the blanks with each other.

2. The method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the plurality of blanks include a bumper beam blank (1), a bracket blank (3) and a pedestrian beam blank (2).

3. A method for manufacturing an integral bumper beam assembly (100) according to claim 1 or 2, wherein the one or more overlapping areas are formed by partially overlapping the bracket blank (3) with the bumper beam blank (1) and / or with the pedestrian beam blank (2).

4. The method for manufacturing an integrated bumper beam assembly (100) according to any one of claims 1-3, wherein joining the blanks comprises welding the blanks to each other.

5. The method for manufacturing an integrated bumper beam assembly (100) according to claim 4, wherein the welding comprises resistance spot welding and / or laser welding.

6. The method for manufacturing an integral bumper beam assembly (100) according to any one of claims 1-5, wherein deforming the composite blank (4) to form the integral bumper beam assembly (100) comprises hot stamping the composite blank (4).

7. Method for manufacturing an integral bumper beam assembly (100) according to any one of claims 1 to 6, wherein the deformation is performed in a single operation.

8. A method for manufacturing an integrated bumper beam assembly (100) according to any one of claims 1-7, wherein the integrated bumper beam assembly (100) includes two or more brackets (30) connecting the bumper beam (10) to the pedestrian beam (20).

9. A method according to any one of claims 1 to 8, wherein at least a portion of the pedestrian beam blank (2) is made of a more ductile material than the bumper beam blank (1).

10. The method according to any one of claims 1 to 9, wherein the bumper beam blank (1) is made of ultra-high strength steel.

11. The method according to any one of claims 1-10, wherein the integral bumper beam assembly (100) comprises a support (60) for an auxiliary system, and optionally wherein the auxiliary system comprises one or more sensors.

12. The method according to any one of claims 1-11, wherein deforming the combined blank (4) to form the integral bumper beam assembly (100) includes providing the bumper beam (10) and the pedestrian beam (20) with a hat-shaped cross-section.

13. The method of claim 12, wherein the hat-shaped cross-section of the pedestrian beam (20) is open on a first side, and the hat-shaped cross-section of the bumper beam (10) is open on a second side, and at least one bracket connects the bumper beam (10) to the pedestrian beam (20).

14. An integral bumper beam assembly obtainable by a method according to any one of claims 1-13.

15. A vehicle comprising the integrated bumper beam assembly according to claim 14.

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