Bumper arrangement for a motor vehicle and method for manufacturing a cross member or an element arranged directly in front of a cross member of a motor vehicle, viewed in the longitudinal direction of a motor vehicle, for a bumper arrangement

Abstract

Bumper arrangement for a motor vehicle with a cross member (16) having a U-shaped cross-section and a body element (44) arranged in front of and at a distance from the cross member (16) when viewed in the longitudinal direction of the vehicle, characterized in that at least one moment support (24) projecting in the longitudinal direction of the vehicle is formed or arranged on the cross member (16) and / or on the body element (44), which, upon contact between the cross member (16) and the body element (44), counteracts a rotational movement (30) between the body element (44) and the cross member (16) due to a relative movement of the cross member (16) and the body element (44) in the longitudinal direction of the vehicle, wherein an opening (28), a predetermined breaking point or an elastic material area is formed or arranged on the other element for receiving the moment support (24) on the body element (44) or cross member (16).

Description

[0001] The invention relates to a bumper assembly according to the preamble of claim 1 and to a method for manufacturing a U-shaped cross member according to claim 8. In particular, the invention relates to a bumper assembly in the area of ​​a front bumper of a motor vehicle. A bumper assembly within the meaning of the invention is understood to be the arrangement of components of a motor vehicle that may include the bumper or of which at least one component is arranged on a bumper in such a way that it moves relative to another component of the bumper assembly even under slight forces (e.g., in the event of a pedestrian collision).

[0002] From DE 36 39 195 A1 a bumper arrangement for a motor vehicle is known in which a cross member designated as a support element, a foam and a bumper are arranged adjacent to one another when viewed in the longitudinal direction of the vehicle.

[0003] A similar arrangement to that described in DE 36 39 195 A1 is also described in DE 32 24 979 A1.

[0004] From EP 1 633 603 B1 a bumper arrangement for a motor vehicle is known in which a cross member is directly connected to insert parts, wherein the bumper with the insert parts is arranged at a distance in the longitudinal direction of the vehicle from a further element (here: bumper cover).

[0005] From DE 10 2005 056 961 A1, a bumper arrangement for a motor vehicle is known in which a body element designated as a spoiler is supported by a rear support element in the form of an engine compartment cover. The engine compartment cover has a plurality of ribs extending longitudinally in the direction of the vehicle, which have a varying rib height along their length.

[0006] From DE 10 2007 052 ​​569 A1 a bumper arrangement for a motor vehicle is known in which a body element designated as a bumper cover is mounted against a front-end mounting bracket via a pedestrian protection cross member formed in one piece with the bumper cover and made of the same material.

[0007] Furthermore, DE 10 2004 053 020 A1 discloses a body part for a motor vehicle with a deformable outer skin. The outer skin conceals a supporting structure and a plurality of elements arranged between the outer skin and the supporting structure, which are deformable upon impact.

[0008] The invention is based on the objective of providing a bumper arrangement for a motor vehicle comprising a crossmember and a body element arranged in front of and at a distance from the crossmember when viewed in the longitudinal direction of the vehicle, as well as a method for manufacturing such elements, which are optimized for pedestrian protection and can be manufactured or implemented cost-effectively. In particular, the invention aims to counteract rotation of the body element around the crossmember.

[0009] The problem is solved according to the invention by the features of the independent claims. Advantageous embodiments are described in the dependent claims.

[0010] A bumper arrangement according to the invention for a motor vehicle comprises a cross member which has a U-shaped cross-section and a body element arranged in front of the cross member and at a distance from the cross member when viewed in the longitudinal direction of the vehicle, wherein at least one moment support projecting in the longitudinal direction of the vehicle is formed or arranged on the cross member and / or on the body element, which, when the cross member and body element come into contact, counteracts a rotational movement between the body element and the cross member due to a relative movement of the cross member and body element in the longitudinal direction of the vehicle.Such a bumper arrangement has the advantage that, in the event of relative movements between the crossmember and the body panel, which occur particularly during accident-related impacts on the front of the vehicle (rear-end collisions and pedestrian collisions), the body panel remains in a controlled position in front of the crossmember and does not rotate around it, thus avoiding energy absorption and its relative position to the crossmember. Maintaining this position of the body panel relative to the crossmember is particularly desirable with regard to pedestrian safety, for example, to prevent injury from excessive knee flexion.A further advantage of a spaced arrangement between the crossmember and the body panel, as described above, is that component tolerances occurring on the crossmember and the body panel itself, as well as on any components connected to them, and assembly-related tolerances, can be relatively large and are not limited by the solution according to the invention. The moment support, which counteracts a rotational movement between the body panel and the crossmember—particularly by means of a positive locking mechanism—only becomes active under load and thus only acts after the application of external forces. The crossmember has a U-shaped cross-section, as such an element exhibits particularly high bending stiffness. Such a U-shaped element is preferably arranged so that, viewed in the longitudinal direction of the vehicle, the open side faces either rearward or forwardward.In the bumper arrangement according to the invention, an opening for receiving the moment support is formed on the respective other element, i.e., if the moment support is formed on the body element, an opening for receiving this moment support is formed on the cross member, and vice versa. An opening for receiving the moment support is preferably funnel-shaped and / or complementary to the moment support. Particularly preferably, the opening is initially funnel-shaped in the area facing the moment support and complementary in the contact area, so that during relative movement between the cross member and the body element, it is first ensured that the moment support is received by the opening, and during further relative movement, the moment support is moved into a complementary position defined by the opening.

[0011] As an alternative to an opening, a predetermined breaking point or an elastic material area can also be provided on the other element, designed so that the moment support dips into the other element during relative movements between the cross member and the body element in order to counteract a rotation of the elements relative to each other.

[0012] In a practical embodiment of a bumper arrangement according to the invention, the body element is a ventilation grille and / or a cover element, in particular a spoiler cladding the engine compartment from below, arranged in the area of ​​the front of a motor vehicle. Such ventilation grilles and cover elements are frequently arranged in the lower area of ​​the front of a motor vehicle, particularly below the area of ​​a bumper generally referred to as the bumper. In this area, the risk of a knee injury as described above is particularly high, so the invention, in conjunction with such a ventilation grille, has a beneficial effect.

[0013] It is possible to form only one moment support and, optionally, only one receptacle in the transverse direction of the cross member on the cross member and the body element. However, it is particularly preferred if a plurality of moment supports and / or receptacles in the transverse direction of the cross member and / or the body element are formed or arranged. Such an embodiment can be manufactured simply and cost-effectively, as will be discussed in detail in connection with the method according to the invention. With regard to the arrangement of moment supports, particular reference is made to the possibility of manufacturing an element (especially a sheet metal part) with one or more moment supports as a separate component and firmly connecting this component to the body element and / or the cross member, for example by gluing, riveting, welding, and / or brazing.

[0014] It is also preferred for manufacturing reasons if the at least one moment support is a material tongue formed integrally on the cross member or the body element. A material tongue is understood to be a material projection that, through the addition of extra or formed material, acts as a moment support, providing a superior connection to adjacent material areas on a component. This applies to all moment supports when multiple moment supports are formed. In this case, no additional components are required, so the invention can be implemented on existing bumper assemblies with virtually no additional cost by forming one or more material tongues (material projections) during manufacturing.

[0015] The formation of one or more material tongues can be achieved in a particularly simple way by one or more punching operations on a material blank and by subsequent forming of the material blank.

[0016] In another practical embodiment of a bumper according to the invention, the body element is arranged adjacent to a bumper cover that is at least partially in the field of vision and / or to a lower cover element of the engine compartment. These elements, like the aforementioned ventilation grille, are located in the lower area of ​​the front of a motor vehicle, where pedestrian protection optimized with regard to knee injuries is of particular importance.

[0017] The invention relates in particular to a crossmember arranged parallel to and below another crossmember. The other crossmember is the "conventional" crossmember known for decades in all motor vehicles, which is usually located directly behind the bumper area. Due to its relative position to the other crossmember, this crossmember can be called the upper crossmember. The invention relates in particular to a lower crossmember, i.e., a crossmember arranged below and parallel to the "conventional" crossmember described above. Such a lower crossmember is preferably connected to the upper crossmember via retaining arms. It often has a lower bending stiffness than the upper crossmember.

[0018] The invention also relates to a method for manufacturing a U-shaped cross member, in particular for a bumper arrangement according to one of the preceding claims, comprising the following method steps: a) Punching out at least one material tongue for a moment support from a material blank using a first tool (36), b) Forming the material tongue and / or the material blank in such a way that at least one material tongue protrudes in the longitudinal direction of the vehicle compared to the adjacent areas of the material blank after the forming process, wherein process steps a) and b) are either followed by the subsequent process step c) or a single punching and bending tool is used to carry out process steps a) and b) in a single operation: c) Forming the material blank (34) with a second tool (38) into a crossbeam with a U-shaped profile, wherein the second tool (38) is a two-part bending tool with a first punch (40a) and a second punch (40b) which are brought together for the forming process, wherein the second punch (40b) has recesses (42) in the areas with formed material tongues (26) on the material blank, so that the second punch (40b) does not come into contact with the material tongues (26) during the forming process.

[0019] In this context, a material tongue is defined in particular as an open area that, after the punching process, remains connected to the material blank via an unpunched area. Such a material tongue can be easily and cost-effectively "folded out" from the remaining area of ​​the material blank. This folding out can be achieved through a separate forming process or simultaneously during a punching process and / or another forming process of the entire material blank. In a particularly preferred embodiment, all punching and forming processes take place in a single operation.

[0020] Further practical embodiments and advantages of the invention are described below in connection with the drawings. They show: Fig. 1. A bumper arrangement known from the prior art, comprising a bumper cover, an upper cross member arranged behind it, and a lower cross member connected to the upper cross member via retaining elements, in a front view. Fig. 2 a sectional view according to lines II - II in Fig. 1, Fig. 3 a detailed view of the in Fig. 2 areas marked with III, Fig. 4 an embodiment of a bumper arrangement according to the invention in a view analogous to Fig. 3, Fig. 5 a perspective representation of the in Fig. 4 shown in the inventive arrangement in a view from an oblique front and Fig. 6a / 6b a schematic representation of two process steps of a process according to the invention.

[0021] Fig. Figure 1 shows a front bumper 10 of a motor vehicle with cutouts 12 for in Fig. 1 ventilation grille (not shown). Behind the front bumper 10, an upper cross member 14 and a lower cross member 16 are arranged, extending over more than 50 percent of the width B of the bumper 10. The upper cross member 14 and the lower cross member 16 are connected to each other by retaining elements 18 extending in the vehicle's vertical direction (z-direction). The upper cross member 14 and the lower cross member 16, as well as the areas of the retaining elements 18 concealed by the bumper 10, are in Fig. 1 shown as a dashed line.

[0022] As in the Fig. As can be seen in Figure 2, both the upper cross member 14 and the lower cross member 16 are U-shaped, with the open side of the U-shaped profile of the upper cross member 14 facing forward when viewed in the longitudinal direction (x-direction) of the vehicle, and the open side of the U-shaped profile of the lower cross member 16 facing rearward when viewed in the longitudinal direction of the vehicle. Fig. Figure 2 also shows a lower cover element 20 for an engine compartment and an associated ventilation grille 22. Due to the aerodynamic importance and design of the lower cover element 20, it is also referred to as a spoiler. An element 10a of the bumper 10 in the lower area partially covers – when viewed from the front of the vehicle – the lower cover element 20 and the ventilation grille 22.

[0023] In Fig. 3, which shows an enlarged representation of the in Fig. As shown in Figure 2, which depicts the area marked III with a bumper assembly 32, it is clearly visible that the lower part of the ventilation grille 22 and the lower cross member 16 are spaced apart from each other by the amount d in the longitudinal direction of the vehicle (x-direction) and are arranged directly adjacent to each other. The ventilation grille 22 is therefore a body element 44 within the meaning of the invention. The amount d is preferably greater than 2 mm and less than 10 mm, and particularly preferably between 3 mm and 5 mm, especially approximately 4 mm. This amount d is provided because the two elements are assigned to different assemblies and the additive component and assembly tolerances of these assemblies must be compensated for.

[0024] An embodiment of a bumper arrangement 32 according to the invention is described below in conjunction with the Fig. 4 and Fig. 5 described. In addition, in connection with the Fig. 6a and Fig. 6b Some process steps of a process according to the invention are explained in more detail. For the purpose of explaining the invention, the same reference numerals are used as in the Fig. 1, Fig. 2 to Fig. 3 is used if the elements are identical or at least functionally equivalent.

[0025] As in Fig. As can be seen in Figure 5, a multitude of material tongues 26, serving as moment supports 24 and projecting forward in the longitudinal direction (x-direction) of the vehicle, are formed on the lower cross member 16 in the transverse direction (y-direction) of the vehicle. Furthermore, as shown in Figure 5, the following details are also present: Fig. As can be seen in Figure 4, funnel-shaped openings 28 for receiving the material tongues 26 are formed on the side of the ventilation grille 22 facing the lower cross member 16. If a relative movement occurs between the ventilation grille 22 and the lower cross member 16, e.g., in the event of an unforeseen collision of the motor vehicle with a pedestrian, the material tongues 26 dip into the funnel-shaped opening 28 of the ventilation grille 22 until the lower cross member 16 comes into contact with the ventilation grille and exert a rotational movement in the direction of arrow 30. Fig. 3 then as moment supports 24 opposite.

[0026] In the Fig. 4 and Fig. In the embodiment of a bumper arrangement 32 shown in Figure 5, the material tongues 26 serving as moment supports 24 are formed in the foremost region of the cross member 16. Additionally or alternatively, material tongues 26 can also be formed in other regions of the cross member 16, in particular in regions that come into contact with the ventilation grille 22 or another body element during relative movement between the cross member 16 and the grille 22, so that the moment supports 24 act directly.

[0027] In the Fig. 6a and Fig. Figure 6b illustrates the simple process steps of a method according to the invention for producing a crossbeam 16 or an element arranged directly in front of the crossbeam 16. In a first process step, a material blank 34, particularly a flat one, is punched using a first tool 36 such that a material tongue 26, which remains partially connected to the material blank 34 even after the punching process, is punched out. Subsequently or simultaneously, the material tongue 26 is "folded out" of the material blank 34 by forming it. In a subsequent process step, according to Fig.6b The material blank 34 is formed with a second tool 38 as a crossbeam 16 with a U-shaped profile. In the illustrated embodiment, the second tool 38 is a two-part bending tool with a first punch 40a and a second punch 40b, which are brought together for the forming process. The second punch 40b has recesses 42 in the areas with formed material tongues 26 on the material blank 34, so that the second punch 40b does not come into contact with the material tongues 26 during the forming process. In general, it should at least be ensured that after the forming process the material tongues 26 protrude in a desired direction relative to the adjacent areas of the material blank 34. This can also be achieved by the fact that the material tongues 26 are only "folded out" during the forming process due to a suitable design of the punches 40a and 40b.

[0028] Instead of the first tool 36 and second tool 38 described, only a single punching and bending tool (not shown) can be used to perform process steps a) and b) in a single operation.

[0029] The features of the invention disclosed in this description, in the drawings, and in the claims can be essential for realizing the invention in its various embodiments, both individually and in any combination. The invention is not limited to the described embodiments. It can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. Reference symbol list 10 bumpers 10a Bumper element 12 Exclusion 14 upper crossbeam 16 lower crossbeam 18 retaining element 20 cover element 22 ventilation grilles 24 Moment support 26 Material tongue 28 Opening 30 Arrow 32 Bumper arrangement 34 Material cutting 36 first tool 38 second tool 40a first stamp 40b second stamp 42 recess 44 Body element B width d amount

Claims

Bumper arrangement for a motor vehicle with a cross member (16) having a U-shaped cross-section and a body element (44) arranged in front of and at a distance from the cross member (16) when viewed in the longitudinal direction of the vehicle, characterized in that at least one moment support (24) projecting in the longitudinal direction of the vehicle is formed or arranged on the cross member (16) and / or on the body element (44), which, upon contact between the cross member (16) and the body element (44), counteracts a rotational movement (30) between the body element (44) and the cross member (16) due to a relative movement of the cross member (16) and the body element (44) in the longitudinal direction of the vehicle, wherein an opening (28), a predetermined breaking point or an elastic material area is formed or arranged on the other element for receiving the moment support (24) on the body element (44) or cross member (16). Bumper arrangement according to the preceding claim, characterized in that the body element (44) is a ventilation grille (22) and / or a cover element (20) arranged in the area of ​​the front of a motor vehicle. Bumper arrangement according to one or more of the preceding claims, characterized in that a plurality of moment supports (24) and / or openings (28) are formed or arranged in the transverse direction of the vehicle of the cross member (16) and / or the body element (44). Bumper arrangement according to one or more of the preceding claims, characterized in that the at least one moment support (24) is a material tongue (26) formed in one piece on the cross member (16) or on the body element (44). Bumper arrangement according to the preceding claim, characterized in that the material tongue (26) is formed by one or more punching operations on a material blank (34) and by subsequent forming of the material blank (34). Bumper arrangement according to one or more of the preceding claims, characterized in that the body element (44) is arranged adjacent to a bumper (10) arranged at least partially in the field of vision and / or to a lower cover element (20) of the engine compartment. Bumper arrangement according to one or more of the preceding claims, characterized in that the cross member (16) is arranged parallel to a further cross member (14) and below this further cross member (14). Method for manufacturing a U-shaped crossbeam (16), characterized by the following process steps: a) punching out at least one material tongue (26) for a moment support (24) from a material blank (34) with a first tool (36), b) forming the material tongue (26) and / or the material blank (34) such that the at least one material tongue (26) projects in the longitudinal direction of the vehicle compared to the adjacent areas of the material blank (34) after the forming process, wherein process steps a) and b) are either followed by the subsequent process step c) or a single punching and bending tool is used to carry out process steps a) and b) in a single operation: c) forming the material blank (34) with a second tool (38) into a crossbeam (16) with a U-shaped profile,wherein the second tool (38) is a two-part bending tool with a first punch (40a) and a second punch (40b) which are brought together for forming, wherein the second punch (40b) has recesses (42) in the areas with formed material tongues (26) on the material blank (34) so ​​that the second punch (40b) does not come into contact with the material tongues (26) during forming.

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