Integrated bumper beam assembly for vehicle

Abstract

The present disclosure relates to a method of manufacturing an integrated bumper beam assembly for a vehicle. The method includes providing a plurality of blanks, joining the blanks to each other to form a composite blank, and deforming the composite blank to form the integrated bumper beam assembly. The integrated 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 joining the blanks includes forming one or more overlapping regions formed by partially overlapping the blanks with each other. The present disclosure further relates to an integrated bumper beam assembly obtained by such a method.

Description

Technical Field

[0001] This application claims the benefit of EP22382650.4, filed on Jul. 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 automobiles incorporate a structural framework designed to withstand all loads that the vehicle may be subjected to during its lifespan. The structural framework is further designed to withstand and absorb impacts in the event of a collision with another vehicle, an obstacle, or a pedestrian.

[0004] The structural framework of a vehicle in this sense, for example an automobile, includes, for example, the following: bumpers, pillars (A-pillar, B-pillar, C-pillar, D-pillar), side impact beams, rockers or sills, hinge pillars, and shock absorbers.

[0005] One structure that plays a role in protecting the vehicle during a collision from the front or the rear is the bumper beam. A bumper typically consists of a bumper beam (i.e., a lateral beam made of a high-strength material that is the main structural part of the bumper) and a cover and absorber structure (which can usually be made of resin).

[0006] The main function of the bumper beam is to protect the vehicle and its occupants. The bumper beam is an energy-absorbing component that protects the vehicle body during a collision. The front bumper beam is usually connected to the front rail by a crash box. Therefore, deformation of the front rail may only occur when the energy absorption capacity of the bumper beam and the crash box is exceeded.

[0007] Furthermore, the vehicle may include a lower bumper beam, also known as a pedestrian beam, at the front end. The pedestrian beam may be coupled to the bumper beam via a vertical bracket and may form a bumper beam assembly. The bumper beam is an energy-absorbing component that protects the vehicle body during a collision, while the lower bumper beam or pedestrian beam is part of the bumper beam assembly aimed at ensuring pedestrian safety.

[0008] Since the bumper beam and the pedestrian beam have different functions, they are usually made of different materials and can be manufactured in different ways.

[0009] The upper beam is a component with the desired high rigidity, generally achieved by hot stamping ( "press hardening"), aiming to be relatively lightweight and limit intrusion during a collision. The pedestrian beam is a member coupled to the bumper beam aimed at protecting pedestrians during a collision. Therefore, the pedestrian beam may be a softer component. Usually, the pedestrian beam is thinner than the bumper beam and is typically made of a material suitable for cold stamping.

[0010] In press hardening, also known as hot forming die quenching (HFDQ), boron steel sheets are usually used to create stamping parts with ultra-high strength steel (UHSS) properties having a tensile strength of, for example, 1500 MPa or 2000 MPa or more. As the strength increases, a thinner gauge material can be used, making it lighter than conventional cold stamping mild steel parts. Throughout the present disclosure, UHSS can be regarded as steel with an ultimate tensile strength of 1000 MPa or more after the press hardening process.

[0011] In the HFDQ process, the blank to be hot-formed can be heated to a predetermined temperature, for example, above the austenitization temperature (especially between Ac3 and the evaporation temperature of the blank coating). For this purpose, a furnace system can be used. Depending on specific needs, additional heaters such as induction heating or infrared heating can be added to the furnace system. By heating the blank, the strength of the blank decreases and the formability improves. That is, the hot stamping process becomes easier.

[0012] Several ultra-high-strength steels (UHSS) for hot stamping and hardening are known. The blank can be made of boron steel with or without a coating such as Usibor® (22MnB5) commercially available from ArcelorMittal.

[0013] Usibor® 1500P is an example of 22MnB5 steel. The composition of Usibor® can be summarized as follows in weight percent (the rest being iron (Fe) and impurities): Maximum carbon (C) content (%): 0.25 Maximum silicon (Si) content (%): 0.4 Maximum manganese (Mn) content (%): 1.4 Maximum phosphorus (P) content (%): 0.03 Maximum sulfur (S) content (%): 0.01 Aluminum (Al) content (%): 0.01 - 0.1 Maximum titanium (Ti) content (%): 0.05 Maximum niobium (Nb) content (%): 0.01 Maximum copper (Cu) content (%): 0.20 Maximum boron (B) content (%): 0.005 Maximum chromium (Cr) content (%): 0.35.

[0014] Usibor® 1500P has a yield strength of, for example, 1100 MPa and an ultimate tensile strength of 1500 MPa.

[0015] The yield strength of Usibor® 2000 is 1400 MPa or more, and the ultimate tensile strength exceeds 1800 MPa. The composition of Usibor® 2000 can be summarized as follows in weight percent (the balance being iron (Fe) and impurities): Maximum carbon (C) content (%): 0.36 Maximum silicon (Si) content (%): 0.8 Maximum manganese (Mn) content (%): 0.8 Maximum phosphorus (P) content (%): 0.03 Maximum sulfur (S) content (%): 0.01 Aluminum (Al) content (%): 0.01 - 0.06 Maximum titanium (Ti) content (%): 0.07 Maximum niobium (Nb) content (%): 0.07 Maximum copper (Cu) content (%): 0.20 Maximum boron (B) content (%): 0.005 Maximum chromium (Cr) content (%): 0.50 Maximum molybdenum (Mb) content (%): 0.50

[0016] As described above, hot formed direct quenching is also referred to as "press hardening", and the term "hot stamping" is also used. These terms are used interchangeably throughout this disclosure.

[0017] Typical vehicle parts that can be manufactured using the HFDQ process include door beams, bumper beams, cross / side members, A / B pillar reinforcements, front rails and rear rails, seat cross members, and roof rails.

[0018] The hot forming of boron steel is becoming increasingly popular in the automotive industry due to its excellent strength and formability. As a result, many structural parts that were conventionally cold formed from mild steel have been replaced by hot formed equivalents with significantly improved strength. This allows the thickness (and thus weight) of the material to be reduced while maintaining the same strength.

[0019] In order to improve the ductility and energy absorption in specific regions of a component, it is known to introduce softer regions within the same component. This improves the ductility locally while maintaining the overall required high strength. By locally adjusting the microstructure and mechanical properties of a specific structural component to consist of regions that are very high in strength (very hard), i.e., have high ultimate tensile strength and yield strength, and regions where the ductility is increased (softer), i.e., have low ultimate tensile strength, low yield strength, and long elongation before fracture, it may be possible to improve the overall energy absorption, maintain structural integrity in a collision situation, and also reduce the overall weight. Such soft regions can also advantageously change the kinematic behavior in the event that the component collapses upon impact.

[0020] Known methods for creating regions of increased ductility (soft zones) in vehicle structural components include providing a tool that includes a pair of complementary upper and lower die units. Each unit has individual die elements (steel blocks). The blank to be hot formed is preheated to a predetermined temperature, for example, 100 - 200 °C. For example, heating by a furnace system above the austenitizing temperature reduces the strength and facilitates the hot stamping process.

[0021] The die elements are designed to operate at different temperatures and have different cooling rates in different regions of the component being formed during the quenching process, such that different material properties of the final product, for example, generally lower ultimate tensile strength and yield strength but greater elongation before fracture, can be obtained. For example, one die element can be cooled to quench the corresponding region of the component being manufactured at a high cooling rate, thereby rapidly lowering the temperature of the component to obtain a hard martensite microstructure. Another adjacent die element can be heated so that the corresponding portion of the component being manufactured is cooled at a lower cooling rate, obtaining a softer microstructure that includes, for example, bainite, ferrite, and / or pearlite. Such regions of the component may remain at a higher temperature than the rest of the component when exiting the die.

[0022] As another method for obtaining hot stamping parts having regions with different mechanical properties, for example, there are adjusting heating or differential heating before stamping, and changing local microstructures by local heat treatment after the stamping process to obtain different mechanical properties. Further, the use of patchwork blanks and tailor welded blanks (TWB) combining different thicknesses and / or materials within the blank are also conceivable.

[0023] UHSS can reach a tensile strength of up to 1500 MPa, or even 2000 MPa or more, especially after press hardening operations. When hardened, UHSS may have a martensite microstructure. This microstructure improves the maximum tensile strength and yield strength per unit weight.

[0024] In addition to the above-mentioned ultra-high strength steel, steels with higher ductility can also be used for parts of the structural skeleton that require energy absorption. These steels can be used in the hot stamping process, but a martensite microstructure cannot be obtained during the process. Examples of suitable steels with higher ductility include Ductibor® 500, Ductibor® 1000, CRL-340LA, etc.

[0025] Another material used for hot stamping is Ductibor® 500. Ductibor® 500 is a steel material with much higher ductility and is effective in absorbing energy during impact. The yield strength of Ductibor® 500 is 400 MPa or more, and the ultimate tensile strength is 550 MPa or more.

[0026] The composition of Ductibor® 500 can be summarized as follows in weight percent (the balance is Fe and impurities): Maximum carbon (C) content (%): 0.1 Maximum silicon (Si) content (%): 0.5 Maximum manganese (Mn) content (%): 1.7 Maximum phosphorus (P) content (%): 0.03 Maximum sulfur (S) content (%): 0.025 Aluminum (Al) content (%): 0.015 - 0.2 Maximum titanium (Ti) content (%): 0.09 Maximum niobium (Nb) content (%): 0.10 Maximum copper (Cu) content (%): 0.20 Maximum boron (B) content (%): 0.001 Maximum chromium (Cr) content (%): 0.20

[0027] Ductibor® 1000 is another material used in hot stamping to increase the elongation rate compared to Usibor® 1500 and Usibor® 2000. The yield strength of Ductibor® 1000 is 800 MPa or more, and the ultimate tensile strength is 1000 MPa or more. The components of Ductibor® 1000 can be summarized as follows in weight percent (the balance being Fe and impurities): Maximum carbon (C) content (%): 0.10 Maximum silicon (Si) content (%): 0.6 Maximum manganese (Mn) content (%): 1.8 Maximum phosphorus (P) content (%): 0.03 Maximum sulfur (S) content (%): 0.01 Aluminum (Al) content (%): 0.01 - 0.1 Maximum titanium (Ti) content (%): 0.05 Maximum niobium (Nb) content (%): 0.10 Maximum copper (Cu) content (%): 0.20 Maximum boron (B) content (%): 0.005 Maximum chromium (Cr) content (%): 0.20

[0028] Since the requirements for each component are very different, bumper beam assemblies are typically manufactured from multiple components. Typically, a bumper beam assembly is formed by hot stamping a bumper beam blank and cold stamping a pedestrian beam blank. After each forming process, the beams may be connected to each other via vertical brackets. The brackets may be welded to both the bumper beam and the pedestrian beam. Thus, a bumper beam assembly is formed, for example, by welding four separate stamp pieces. Welding is usually performed by metal active gas (MAG). Disclosure of the Invention Problems to be Solved by the Invention

[0029] One problem encountered is that multiple weld spots and seams can lead to vulnerable areas during a collision. Weight, manufacturability, and cost are also issues to be considered.

[0030] This disclosure provides examples of systems and methods that at least partially address some of the above-mentioned drawbacks. Means for Solving the Problems

[0031] In a first aspect, a method of manufacturing an integrated bumper beam assembly for a vehicle is provided. The method includes providing a plurality of blanks, joining the blanks to form a composite blank, and deforming the composite blank to form a bumper beam assembly, the bumper beam assembly including a bumper beam, a pedestrian beam, and at least one bracket connecting the bumper beam to the pedestrian beam.

[0032] By joining blanks together to form a composite blank and then deforming the composite blank, a lightweight and durable bumper beam assembly is manufactured with fewer steps. By joining the blanks before deformation, post-forming welding operations are reduced, enabling the production of a bumper beam assembly with no or few heat-affected zones. Fewer heat-affected zones reduce the risk of cracking during an accident.

[0033] In this specification, a bracket can be considered a substantially vertical connector for attaching a bumper beam to a pedestrian beam.

[0034] In some examples, blanks of different material thicknesses and / or grades may be used to meet specific strength, intrusion prevention, and energy absorption requirements and to optimize weight.

[0035] In some examples, the plurality of blanks includes 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 more ductile material than the bumper beam blank.

[0036] Throughout this disclosure, a bumper beam blank may be considered a blank that is subsequently deformed to form a bumper beam. Similarly, a pedestrian beam blank and a bracket blank may be considered blanks that are subsequently deformed to form a pedestrian beam and a bracket, respectively.

[0037] A bumper beam blank may be a blank formed by one or more sub-blanks. A pedestrian beam blank may also be a blank formed by one or more sub-blanks. The bumper beam blank and the pedestrian beam blank may be joined by at least one bracket.

[0038] In some examples, deforming the joined blank to form the one-piece bumper beam assembly includes hot stamping the joined blank. Hot stamping is a process that appropriately deforms ultra-high strength steel to form the complex structure of the one-piece bumper beam assembly.

[0039] In some examples, deforming the joined blank may be performed in a single operation. This can increase the strength of the bumper beam assembly while reducing the thickness of the blank and reducing the weaknesses of the final assembly. The joined blank may be formed prior to the deformation operation. The risk of cracking in the one-piece bumper beam assembly during a collision event is reduced as there is no risk caused by joining.

[0040] In a further aspect, a one-piece bumper beam assembly obtained by the method according to any of the examples described herein is provided.

Brief Description of the Drawings

[0041]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6

Figure 7

Figure 8

Figure 9A

Figure 9B

Figure 10

[0042] Non-limiting examples of the present disclosure will be described below with reference to the accompanying drawings. The figures illustrate embodiments and can be used only as an aid in understanding the claimed subject matter and do not limit the claimed subject matter in any way.

[0043] In these figures, the same reference numerals are used to indicate corresponding elements.

[0044] Figure 1 shows a state-of-the-art bumper beam assembly. This bumper beam assembly is composed of a bumper beam 10, a pedestrian beam 20, and two connection brackets 30. This bumper beam assembly is made from four independent components, which are then welded together. The bumper beam 10 can be regarded as the main component of the bumper designed to absorb impacts. The bumper beam 10 can be made from UHSS by a hot stamping process. In the example, the bumper beam 10 can include one or more softer zones, i.e., zones with lower mechanical strength than other parts of the bumper beam, to enhance energy absorption during impacts and control the movement of deformation.

[0045] The pedestrian beam 20 generally does not require the same strength and rigidity and can be created by cold forming. For example, dual-phase steel or complex-phase steel can be used. The pedestrian beam 20 is generally configured to avoid or reduce lower limb injuries during a collision with a pedestrian.

[0046] A grille (not shown), i.e., a cover for an opening of a vehicle for an air inlet or outlet, can generally be arranged between the bumper beam 10 and the pedestrian beam 20. The arrangement of the bracket 30 can be adapted to the desired shape of the grille.

[0047] FIG. 2 schematically shows an integrated bumper beam assembly 100 of a vehicle according to an example of the present disclosure. The integrated bumper beam assembly 100 includes a bumper beam 10, a pedestrian beam 20, and at least one connection bracket 30. The bumper beam 10 and the pedestrian beam 20 are connected to the vehicle via a crash box 40.

[0048] In this example, the crash box 40 is provided on both the bumper beam 10 and the pedestrian beam 20. In other examples, the crash box 40 is provided only on the bumper beam 10. The crash box 40 of the bumper beam 10 may be connected to the rails of the vehicle framework.

[0049] In some examples, the integrated bumper beam assembly 100 may define a front collision management system of the vehicle. That is, the assembly may be arranged on the front side of the vehicle and may be connected to the front rails.

[0050] The one-piece bumper beam assembly 100 can be manufactured from a plurality of blanks in a single deformation process. As schematically shown in FIG. 3, the one-piece bumper beam assembly 100 can be manufactured from three blanks, namely a first blank 1, a second blank 2, and a third blank 3. The first blank 1 can be a bumper beam blank 1, the second blank 2 can be a pedestrian beam blank 2, and the third blank 3 can be a bracket blank 3. The bumper beam blank 1 can be joined to the bracket blank 3, and the bracket blank 3 can be joined to the pedestrian beam blank 2. In this way, as shown in FIG. 4, a composite blank 4 including the three blanks 1, 2, and 3 can be formed. The blanks can be welded to each other, for example, by laser welding or spot welding. In a subsequent process, the composite blank 4 can be heated and deformed.

[0051] In other examples, the bumper beam assembly 100 is made from a first blank 1 and a second blank 2. The first blank 1 is a bumper beam blank 1, and the second blank 2 is a pedestrian beam blank 2. In these examples, the first and / or second blanks 1, 2 can include a part of the blank forming the bracket 30.

[0052] In some embodiments, the bumper beam blank 1 may be formed of a single blank. In other examples, the bumper beam blank 1 may be formed of a plurality of blanks or sub-blanks of, for example, different thicknesses and / or different materials. In these examples, the plurality of blanks forming the bumper beam blank 1 may be tailor welded blanks (TWB). The TWB may be formed by joining the sub-blanks by edge-to-edge welding, and the welding may include laser welding. In other examples, the plurality of blanks forming the bumper beam blank 1 may be joined by forming one or more overlapping regions formed by partially overlapping the blanks with each other. In these cases, any of laser welding, arc welding, or spot welding may be used.

[0053] In some examples, the bumper beam blank 1 may comprise at least one vertical vertical portion to form (a part of) the bracket 30. The vertical vertical portion may be of a width sufficient to ensure a functional and safe joint between the bumper beam blank 1 and the pedestrian beam blank 2.

[0054] In some embodiments, the pedestrian beam blank 2 is formed by a single blank. In other examples, the pedestrian beam blank 2 is formed by a plurality of blanks such as a tailor welded blank including sub-blanks of different thicknesses and / or different materials.

[0055] In some examples, the pedestrian beam blank 2 may comprise at least one vertical vertical portion. The vertical vertical portion may be of 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.

[0056] As schematically shown in FIG. 4, the blanks forming the integrated bumper beam assembly 100 may be joined to form the coupling blank 4. In one example, the coupling blank 4 may be formed by joining the bumper beam blank 1 to the pedestrian beam blank 2 at least by the bracket blank 3. The bracket blank 3 may function 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, specifically 5 - 15 cm.

[0057] 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 (specifically edge-to-edge) or spot welding. The region 5 where the blanks are joined is shown in FIG. 4. In some examples, the width W2 of the overlapping 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) may be, for example, 2 cm to 10 cm. The appropriate dimensions of the overlapping region may be selected considering the requirements of weldability, strength, and rigidity. A larger overlapping region means an increase in thickness over a wider area, and thus an increase in the local strength and rigidity of the bumper beam.

[0058] As can be seen from some of the following examples, the overlapping region may be part of the U-shaped sidewall formed in the hot stamping process or may cover the entire height of the sidewall.

[0059] Similarly, an overlapping region may also be formed between the bracket blank and the pedestrian beam blank.

[0060] Therefore, one or more overlapping regions may be formed in the transition region between the bumper beam and the bracket beam and / or in the transition region between the pedestrian beam and the bracket beam to reinforce these regions. The one or more overlapping regions may be formed within the horizontal portion of the bumper beam and / or within the horizontal portion of the pedestrian beam. The thickness obtained by the overlapping region increases the strength and rigidity of the transition region, realizing a more resistant bumper beam assembly.

[0061] In some examples, the bracket blank 3 may be joined to the bumper beam blank 1 on 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.

[0062] As schematically shown in FIG. 5A, in some examples, the integrated bumper beam assembly 100 includes one bracket 30b that connects the bumper beam 10 to the pedestrian beam 20. In other examples, the integrated bumper beam assembly 100 includes two or more brackets 30 that connect the bumper beam 10 to the pedestrian beam 20. FIG. 5B shows an example of an integrated bumper beam assembly 100 that includes two brackets 30a, 30c that connect the bumper beam 10 to the pedestrian beam 20. In other examples, the integrated bumper beam assembly 100 includes three brackets that connect the bumper beam 10 to the pedestrian beam 20. Depending on the integrated bumper beam assembly and the design of the vehicle, multiple possibilities are conceivable.

[0063] In another example (not shown), the composite blank 4 can be formed by directly joining the bumper beam blank 1 including one or more vertical portions to the pedestrian beam blank 2, or by joining the vertical portion of the bumper beam blank 1 to the pedestrian beam blank 2. In another example, the composite blank 4 can be formed by directly joining the bumper beam blank 1 to the pedestrian beam blank 2, or by directly joining at least one vertical portion of the pedestrian beam blank 2 to the bumper beam blank 1. When forming the composite blank in this way, there may be fewer joining steps.

[0064] In some examples, the plurality of blanks forming the composite blank 4 can be made of different materials. At least a portion of the blanks can be made of ultra-high strength steel (UHSS). In some examples, the bumper beam blank 1 can be made of ultra-high strength steel. Boron steel, such as 22MnB5, or other steel compositions described above may be suitable UHSS. These blanks, such as boron steel blanks, may include an aluminum silicon coating or a zinc coating.

[0065] The plurality of blanks forming the composite blank 4 may be composed of 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 of Usibor® (e.g., Usibor® 1500 or Usibor® 2000) and blanks or parts of blanks of Ductibor® (e.g., Ductibor® 500 or Ductibor® 1000) may be used as the blanks forming the composite blank 4. When these types of materials are used in a hot forming and subsequent quenching process, Usibor® parts such as bumper beam blanks mainly have a martensite structure, and Ductibor® parts such as pedestrian beam blanks and / or bracket blanks mainly have a ferrite pearlite structure. According to these aspects, the characteristics of the integrated bumper beam assembly 100 can be customized.

[0066] In some examples, the integrated bumper beam assembly 100 can include regions having different ultimate tensile strengths, according to any of the examples described herein. In some of these examples, the regions having different ultimate tensile strengths can have different microstructures.

[0067] In some examples, at least one of the blanks 1, 2, 3 can include regions having different ultimate tensile strengths. The blank may be composed of two different materials having different tensile strengths. Thus, the ductility of the region with a lower tensile strength is higher, and thus the energy absorption during a collision may increase.

[0068] In a hot-formed bumper beam assembly, different microstructures can be generated. These different microstructures may be generated by heating the composite blank 4 above the austenitizing temperature and then controlling the cooling of the composite blank 4 when forming the composite blank 4 to form a bumper beam assembly. The cooling of different regions of the composite blank 4 can be controlled by providing heaters in the regions of the forming tool. Therefore, the integrated bumper beam assembly 100 includes a region mainly having a martensite structure and a region containing ferrite, pearlite, bainite, or a mixture thereof. Alternatively, a part of the integrated bumper beam assembly can be partially heated, for example, using a laser beam, and the press-hardened mainly martensite structure can be changed to a structure containing ferrite and / or pearlite and / or bainite and / or tempered martensite and mixtures thereof to create different microstructures. The tensile strength of the mainly martensite structure is 1400 MPa or more, specifically 1500 MPa or more, while the region with low strength is less than 1000 MPa, specifically less than 800 MPa, for example, between 800 MPa and 500 MPa.

[0069] Therefore, the bumper beam blank 1 may be made of a material that may be effective in absorbing energy during a collision. In some examples, the bumper beam blank 1 may be made of at least ultra-high-strength steel.

[0070] The thickness of the bumper beam 10 may be 1.5 to 3 mm. The bumper beam 10 may have an ultimate tensile strength of 1500 to 2000 MPa.

[0071] The pedestrian beam blank 2 may be made of a material different from that of the bumper beam blank 1. The pedestrian beam blank 2 may be made of a material and thickness that meet the pedestrian protection requirements. The thickness of the pedestrian beam 20 may be thinner than the thickness of the bumper beam 10. In one example, at least a part of the pedestrian beam blank 2 is made of a material that is more ductile than the bumper beam blank 1.

[0072] The thickness of the pedestrian beam 20 may be 1 to 2 mm. The pedestrian beam 20 may have an ultimate tensile strength of 500 to 1000 MPa.

[0073] The bracket blank 3 can be manufactured from a material that is more ductile than the bumper beam blank 2. In this way, the bracket 30 can accurately control the deformation during a collision. In other examples, the material of the bracket blank 3 may be the same as the material of the bumper beam blank 1.

[0074] In other examples, the bracket 30 can be manufactured from the same material as the pedestrian beam 20. The thickness of the bracket 30 may be 1.5 to 3 mm. The bracket 30 may have an ultimate tensile strength of 500 to 1000 MPa.

[0075] In some examples, the joining of the blanks includes welding the blanks together. In some examples, the blanks may be welded by spot welding and / or laser welding. Joining the blanks before deformation may facilitate joining because the blanks are substantially flat during joining. Welding the blanks by laser and / or spot welding before the deformation process is efficient and accurate.

[0076] Figure 6 schematically shows an example of the joined blanks after deformation. In this example, the bracket blank 3 can be joined to the bumper beam blank 1 and the pedestrian beam blank 2 by overlaying one blank on the other and using spot welding. In some examples, the overlap region 5 between the bracket blank and the bumper beam blank and the pedestrian beam blank may have a width of 2 cm to 10 cm.

[0077] In other examples, joining the blanks together can include forming one or more overlapping regions formed by partially overlapping the blanks with each other. In other examples, one or more overlapping regions can be formed by partially overlapping the bracket blank 3 with the bumper beam blank 1 and / or the pedestrian beam blank 2. This can be done by laser or spot welding.

[0078] When joining the blanks, there may be a weld seam or a weld spot, which is an important area that can be easily damaged during a vehicle accident. By deforming after joining, it is possible to ensure that there is no weld seam or weld spot between the blanks, improving the durability of the integrated bumper beam assembly 100. In the integrated bumper beam assembly 100, since the risk caused by this weld seam or weld spot is eliminated, the risk of cracking in the integrated bumper beam assembly 100 during a collision is reduced.

[0079] The process of deforming the composite blank 4 to form the integrated bumper beam assembly 100 can include hot forming or hot stamping the composite blank 4.

[0080] In some examples, hot forming can include heating the composite blank above the austenitization temperature and then forming the composite blank to create the integrated bumper beam assembly. In some examples, the forming can include two or more forming steps. These forming steps can include, for example, forming, trimming, or cutting and can be performed in a single multi-stage press. Examples of multi-stage presses are known, for example, from US9,492,859B2 and WO2016142367A1.

[0081] The deformation includes hot forming, i.e., heating the combined blank in a furnace, probably above the austenitizing temperature, specifically above Ac3. After heating in the furnace, the combined blank 4 is transferred to a press where the combined blank 4 is deformed to obtain the final shape of the integrated bumper beam assembly 100. Quenching is performed during and immediately after forming. In particular, quenching includes cooling at a rate exceeding the critical cooling rate so as to obtain a martensite microstructure. In some examples, quenching may be avoided in selected portions of the bumper beam assembly.

[0082] In some examples, the deformation is performed in one operation. By deforming the combined blank 4, an integrated bumper beam assembly 100 with improved crash resistance and manufactured in fewer steps may be provided.

[0083] In some examples, deforming the composite blank 4 to form the integrated bumper beam assembly 100 includes providing hat-shaped cross-sections to the bumper beam 10 and the pedestrian beam 20 to better support the bending load.

[0084] In some examples, as shown in FIGS. 5A and 5B for example, 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. In other examples, as shown in FIG. 7, 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 also open on the first side. At least one bracket 30 can connect the bumper beam 10 to the pedestrian beam 20.

[0085] FIG. 8 shows a side view of the integrated bumper beam assembly 100 and can further understand the connection between the bumper beam 10 and the pedestrian beam 20 formed by the bracket 30.

[0086] Figure 9A schematically shows a further example of the bumper beam assembly 100. In the example of Figure 9A, the integrated bumper beam assembly 100 may include supports 60 for an auxiliary system. In the example of Figure 9A, two supports 60 are included. The size and position of the supports may vary according to the specific requirements of the auxiliary system. The auxiliary system may include one or more sensors, such as proximity sensors for assisting in parking the vehicle. The support 60 may be joined to the bumper beam blank before deforming the composite blank. That is, the support 60 forms part of the composite blank 4, and the bumper beam assembly is reformed by a single deformation process, specifically a single forming process, such as hot stamping. The addition of the auxiliary system is ensured without adding weld seams or spots to the integrated bumper beam assembly 100 that may be damaged during a collision. Unnecessary danger areas can be avoided.

[0087] In some examples, the support 60 for the auxiliary system may have a thickness of 1.5 to 3 mm. In some examples, the support 60 for the auxiliary system may have an ultimate tensile strength of 500 to 1500 MPa. In other examples, the maximum tensile strength of the support 60 for the auxiliary system is 500 to 1000 MPa.

[0088] The blank for forming the support 60 can be joined to the bumper beam blank by laser welding, such as edge-to-edge welding. In another example as shown in Figure 9B, the blank for the support 60 can be joined to the bumper beam blank by overlapping one blank with the other and using spot welding.

[0089] Figure 10 represents a flowchart of a method for manufacturing an integrated bumper beam assembly for a vehicle 200. This method includes preparing a plurality of blanks (201), joining the blanks together to form a composite blank (202), and deforming the joined blank to form an integrated bumper beam assembly (203).

[0090] In some examples, the step (201) of providing a plurality of blanks includes 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 are made of different materials. In some examples, the bumper beam blank is made of ultra-high strength steel, and the pedestrian beam blank is made of a material with higher ductility than the bumper beam blank.

[0091] In some examples, the step (202) of joining the blanks together to form a combined blank includes welding the blanks together. The blanks may be welded by spot welding and / or laser welding.

[0092] The step (203) of deforming the combined blank to form a one-piece bumper beam assembly includes hot forming or hot stamping the combined blank. In the hot-formed bumper beam assembly, different microstructures may be generated. These different microstructures can be created by heating the composite blank above the austenitizing temperature. In some examples, quenching may be performed during and after forming. Quenching may include cooling at a rate above the critical cooling rate so as to obtain a martensite microstructure.

[0093] In some examples, different microstructures may be obtained by heating the composite blank above the austenitizing temperature and then controlling the cooling of the composite blank when forming the composite blank to form a bumper beam assembly. In some examples, quenching can be avoided at selected portions of the one-piece bumper beam assembly.

[0094] In some examples, deforming the composite 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 composite blank 203 includes a bumper beam 10, a pedestrian beam 20, and at least one bracket 30 that connects the bumper beam to the pedestrian beam.

[0095] For completeness, various aspects of the present disclosure are set forth in the following numbered paragraphs.

[0096] Paragraph 1. A method of manufacturing an integrated bumper beam assembly (100) for a vehicle, the method comprising the following steps: Providing a plurality of blanks (1, 2, 3); Combining the blanks to form an integrated blank (4); Deforming the combined blank (4) to form an integrated bumper beam assembly (100). The integrated bumper beam assembly (100) includes a bumper beam (10), a pedestrian beam (20), and at least one bracket (30) that connects the bumper beam to the pedestrian beam.

[0097] Paragraph 2. The method of manufacturing the integrated bumper beam assembly (100) according to Paragraph 1, wherein joining the blanks includes welding the blanks together.

[0098] Paragraph 3. The method of manufacturing the integrated bumper beam assembly (100) according to Paragraph 2, wherein the welding includes resistance spot welding and / or laser welding.

[0099] Paragraph 4. The method of manufacturing the integrated bumper beam assembly (100) according to any one of Paragraphs 1 to 3, wherein deforming the composite blank (4) to form the integrated bumper beam assembly (100) includes hot stamping the composite blank (4).

[0100] Item 5. A method for manufacturing the integrated bumper beam assembly (100) according to any one of Items 1 to 4, wherein the deformation is performed in a single operation.

[0101] Item 6. A method for manufacturing the integrated bumper beam assembly (100) according to any one of Items 1 to 4, wherein the deformation is performed in a plurality of operations.

[0102] Item 7. A method for manufacturing the integrated bumper beam assembly (100) according to any one of Items 1 to 6, wherein the integrated bumper beam assembly (100) includes two or more brackets (30) that connect the bumper beam (10) to the pedestrian beam (20).

[0103] Item 8. The method according to any one of Items 1 to 7, wherein the plurality of blanks includes a bumper beam blank (1) and a pedestrian beam blank (2).

[0104] Item 9. The method according to Item 8, wherein the bumper beam blank (1) is directly joined to the pedestrian beam blank (2).

[0105] Item 10. The method according to Item 8, wherein the plurality of blanks includes a bumper beam blank (1), a bracket blank (3), and a pedestrian beam blank (2).

[0106] Item 11. The method according to any one of Items 1 to 10, wherein the step of joining the blanks includes forming one or more overlapping regions formed by partially overlapping the blanks with each other.

[0107] Item 12. The method according to Item 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).

[0108] Item 13. The method according to any one of Items 1 to 12, wherein the thickness of the pedestrian beam (20) is smaller than the thickness of the bumper beam (10).

[0109] Item 14. The method according to item 8, wherein at least a part of the pedestrian beam blank (2) is made of a material with higher ductility than the bumper beam blank (1).

[0110] Item 15. The method according to item 8, wherein the bumper beam blank (1) is made of ultra-high-strength steel.

[0111] Item 16. The method according to any one of items 1 to 15, wherein the bumper beam (10) has an ultimate tensile strength of 1200 MPa to 2200 MPa, specifically 1400 MPa to 2000 MPa.

[0112] Item 17. The method according to any one of items 1 to 16, wherein the pedestrian beam (20) has an ultimate tensile strength of 500 MPa to 1000 MPa, specifically 500 MPa to 800 MPa.

[0113] Item 18. The method according to any one of items 1 to 17, wherein the integrated bumper beam assembly (100) comprises a support (60) for an auxiliary system, and optionally the auxiliary system comprises one or more sensors.

[0114] Item 19. The method according to item 18, wherein the thickness of the support (60) for the auxiliary system is 1.5 to 3 mm.

[0115] Item 20. The method according to item 19, wherein the maximum tensile strength of the support (60) for the auxiliary system is 500 to 1500 MPa, specifically 500 to 1000 MPa.

[0116] Item 21. The method according to any one of items 1 to 20, wherein deforming the bonding blank (4) to form the integrated bumper beam assembly (100) includes providing the bumper beam (10) and the pedestrian beam (20) with a hat-shaped cross-section.

[0117] Item 22. The method according to Item 21, wherein the hat-shaped cross-section of the pedestrian beam (20) is open on a first side, 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).

[0118] Item 23. The method according to Item 21, wherein the hat-shaped cross-section of the pedestrian beam (20) is open on a first side, the hat-shaped cross-section of the bumper beam (10) is also open on the first side, and at least one bracket (30) connects the bumper beam (10) to the pedestrian beam (20).

[0119] Item 24. The method according to any one of Items 1 to 22, wherein the deformation is carried out by a multi-stage press.

[0120] Item 25. An integrated bumper beam assembly obtained by the method according to any one of Items 1 to 24.

[0121] Item 26. The integrated bumper beam assembly according to Item 25, wherein the integrated bumper beam assembly is a front bumper beam assembly.

[0122] Item 27. A vehicle provided with the integrated bumper beam assembly according to Item 26.

[0123] Although only some examples have been disclosed here, other alternative, modified, usage, and / or equivalent examples are also possible. Furthermore, any possible combination of the described examples is also targeted. Therefore, the scope of the present disclosure should not be limited to specific examples and should be determined only by fairly reading the following claims.

Claims

1. The process involves preparing multiple blanks (1, 2, 3), A step of joining blanks to form a composite blank (4), The process involves deforming the joining blank (4) to form an integrated bumper beam assembly (100), and Includes, 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. Multiple blanks include a bumper beam blank (1) and a pedestrian beam blank (2). The process of joining blanks includes the process of forming one or more overlapping regions by partially overlapping the blanks with each other. A method for manufacturing an integrated bumper beam assembly (100) for a vehicle.

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

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

4. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the step of joining the blanks includes welding the blanks together.

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

6. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the step of deforming a composite blank (4) to form an integrated bumper beam assembly (100) includes hot stamping the composite blank (4).

7. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the deformation is performed in a single operation.

8. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, comprising two or more brackets (30) connecting a bumper beam (10) to a pedestrian beam (20).

9. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein at least a portion of the pedestrian beam blank (2) is made from a material that is more ductile than the bumper beam blank (1).

10. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the bumper beam blank (1) is made from ultra-high-strength steel.

11. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the integrated bumper beam assembly (100) comprises a support (60) for an auxiliary system, and optionally the auxiliary system comprises one or more sensors.

12. A method for manufacturing an integrated bumper beam assembly (100) according to claim 1, wherein the step of deforming a composite blank (4) to form an integrated bumper beam assembly (100) includes the step of providing a hat-shaped cross section to the bumper beam (10) and the pedestrian beam (20).

13. A method for manufacturing an integrated bumper beam assembly (100) according to claim 12, wherein the hat-shaped cross section of the pedestrian beam (20) is open on a first side, 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 integrated bumper beam assembly obtained by the manufacturing method described in claim 3.

15. A vehicle comprising the integrated bumper beam assembly described in claim 14.

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