Motor vehicle component and method for producing a motor vehicle component

Abstract

The invention relates to a motor vehicle component (1) for a motor vehicle, comprising a main strut (2) extending in the transverse direction (Y) of the motor vehicle in the installed position, and an auxiliary strut (3) extending substantially parallel to it and offset, which also extends oriented in the transverse direction (Y) of the motor vehicle, wherein the main strut (2) and the auxiliary strut (3) are connected to one another via at least one connecting strut (4), characterized in that the main strut (2) and the auxiliary strut (3) are designed in their cross-section as a closed hollow profile (14) and the main strut (2), the auxiliary strut (3) and the connecting strut (4) are manufactured in one piece and from the same material.

Description

[0001] The following invention relates to a motor vehicle component according to the features in the preamble of claim 1.

[0002] The present invention further relates to a method according to the features in claim 10.

[0003] It is known from the prior art to provide motor vehicles that have a so-called self-supporting vehicle body. This means that the passenger compartment, as well as the mounting points for a chassis, are integrated into the vehicle body.

[0004] In the area of ​​the front axle, and also in the area of ​​the rear axle, so-called strut towers, also known as strut towers, are located in the area of ​​a wheel arch or wheel suspension. A corresponding strut, for example a spring damper element, is then inserted into this tower from the outside. This can be, for example, a McPherson strut suspension. However, other independent wheel suspensions or axles may also be present.

[0005] Especially during driving, and particularly when cornering, dynamic forces acting on the wheels create stresses in the vehicle body. The vehicle body can twist or flex slightly. When designing the stiffness of a vehicle body, this is also referred to as torsional stiffness. To minimize these twists and flexes when cornering or during other dynamic driving conditions, stiffening or reinforcing elements are used.

[0006] Strut braces are used particularly in the area of ​​the strut towers. These are braces that extend laterally across the vehicle and are usually attached to the upper part of the respective strut tower, primarily with bolts. This connects the strut towers on opposite sides in the transverse direction, so that the strut brace acts as a push or pull rod, providing additional stiffening to the vehicle's handling.

[0007] For example, such a strut is known from DE 10 2015 118 810 A1.

[0008] Furthermore, generic motor vehicle components are known from DE 10 2012 021 857 A1 or DE 10 2007 034 826 A1.

[0009] The object of the present invention is to provide a motor vehicle component, in particular a strut brace or bumper cross member, which produces a high degree of stiffness and freedom of shape, while at the same time being easy to produce.

[0010] The aforementioned problem is solved with a motor vehicle component for a motor vehicle having the features in claim 1.

[0011] The process engineering part of the problem is solved by the features in claim 10.

[0012] Advantageous embodiments of the invention are described in the dependent claims.

[0013] The motor vehicle component, in particular a strut brace for a motor vehicle or a bumper crossmember, has a main strut extending in the transverse direction of the motor vehicle when installed. Furthermore, the strut brace has an auxiliary strut running substantially parallel to the main strut and offset from it. For the purposes of this invention, "parallel" does not necessarily mean that two straight lines are perfectly parallel. Both the main strut and the auxiliary strut are oriented substantially in the transverse direction of the motor vehicle. Depending on installation space requirements, for example, to bridge an engine in the form of an internal combustion engine or similar, both the main strut and the auxiliary strut may also have bends or features in the vertical or longitudinal direction of the motor vehicle. The main longitudinal axis or...However, the main direction of the longitudinal course of the main strut and also the auxiliary strut, as already mentioned, is oriented in the transverse direction of the motor vehicle, so that the main strut and auxiliary strut are essentially arranged parallel to each other.

[0014] The main strut and the auxiliary strut are connected to each other via at least one connecting strut.

[0015] For ease of understanding, the automotive component is described below using the example of a strut brace. However, the automotive component can also be designed as a crossmember in the form of a bumper crossmember. Therefore, the terms "strut brace" and "bumper crossmember" can be used interchangeably, and the described embodiments can be used interchangeably or transferred between each other.

[0016] According to the invention, the strut is now characterized in that the main strut and the auxiliary strut are each designed as a closed hollow profile in their cross-section. This hollow profile preferably has a rectangular cross-section. The connecting strut arranged between the main strut and the auxiliary strut preferably has a round cross-section. "Round" means not only "circular" but also "oval".

[0017] Furthermore, the main strut, the auxiliary strut, and the connecting strut are simultaneously manufactured in one piece and from a single material. In the context of the invention, this means that the main strut, auxiliary strut, and connecting strut are formed in one piece. This is achieved in particular according to the manufacturing process described below, which involves the cutting and forming of an extruded profile. Thus, in the context of the invention, "one piece" and "from a single material" or "one-piece" mean that, in particular, no additional joining operation of the three components is required; therefore, no welding or other joining is necessary.

[0018] Preferably, the connecting strut itself is designed as a closed hollow profile in cross-section. The connecting strut runs at an angle between the main and auxiliary struts, so that they are connected via the connecting strut.

[0019] A connecting strut may be present, which then runs diagonally between the main and auxiliary struts. However, according to the invention, two connecting strut sections may also be formed, whereby in the case of two connecting strut sections these may be arranged mirror-symmetrically and result in an increase in bending and torsional stiffness with simultaneously more symmetrical plastic and elastic deformation behavior during driving and in crashes, and wherein each section runs diagonally.

[0020] In particular, the angle at which the connecting strut runs is between 10° and 45°, most preferably between 12° and 30°, and especially between 15° and 25°. This has resulted in an optimum during the manufacturing process from the extruded profile, with regard to the formability and inherent stiffness of the manufactured strut.

[0021] According to the invention, two connecting struts can also be formed. The two connecting struts are then arranged side by side in cross-section, with both connecting struts being arranged between the main strut and the auxiliary strut of the hollow chamber of the main strut and the auxiliary strut.

[0022] In a further preferred embodiment of the invention, the main strut and connecting strut, or the connecting strut and auxiliary strut, can be coupled to one another in cross-section by a connecting web or a web. This proves advantageous for the manufacturing process. First, an extruded profile can be provided, which can then be machined in the area of ​​the connecting web, particularly in sections along its length, for example, by a cutting operation. Subsequently, by forming, the hollow chamber of the future main strut and the hollow chamber of the future auxiliary strut can be pulled apart or moved away from each other, relative to the installation situation in the longitudinal direction of the vehicle, so that the connecting strut acquires its inclined profile between the main strut and the auxiliary strut as a result of this bending operation.

[0023] For this purpose, the connecting strut is coupled to the main strut, particularly in an outer section of its length, specifically between 4% and 25%, and especially between 5% and 15% of its total length. In particular, the connecting strut runs parallel to the main strut in this area.

[0024] Furthermore, it is particularly preferred that in a middle length section between 4% and 25%, especially between 5% and 15% of the total length of the strut, the connecting strut runs parallel to the auxiliary strut and is coupled to the auxiliary strut, particularly in this section.

[0025] In the described case, there is a connecting strut which runs in two parts at an angle between the main strut and the auxiliary strut.

[0026] In a further preferred embodiment of the present invention, the main strut and the auxiliary strut are themselves configured with a rectangular cross-section. The rectangular configuration has an advantageous cross-section with regard to the subsequent connection stiffness as a tension-compression strut and is simultaneously particularly torsionally stiff against both torsion and bending about the vehicle vertical direction.

[0027] The connecting strut itself has a round cross-section. This, in turn, offers an advantage with regard to the forming operation for manufacturing the strut.

[0028] The aforementioned strut brace or bumper crossmember can be manufactured using the manufacturing process described below, which is illustrated using the example of a strut brace:

[0029] The aforementioned strut brace can be manufactured using the production process described below. The process comprises the following steps: • Providing an extruded profile which has a hollow chamber on the outside in cross-section and a solid material or a third hollow chamber in the middle, wherein the hollow chambers are connected to the solid material or the middle hollow chamber in cross-section via a connecting web, • Separating the connecting webs section by section, • Pulling apart the outer hollow chambers in such a way that a main strut is formed through a first hollow chamber and, parallel to it and spaced apart, an auxiliary strut is formed through a second hollow chamber, and the solid material or the middle hollow chamber forms a connecting strut which connects the main strut and the auxiliary strut in one piece and with a uniform material, • Optional further processing, in particular reshaping and / or punching and / or trimming of the strut produced in this way, • Optional heat treatment of the dome brace produced in this way by natural aging for at least one day or artificial aging for at least six hours.

[0030] For all the aforementioned designs of the strut brace, it is preferable that it be manufactured from a light metal alloy, in particular an aluminum alloy. For this purpose, a raw material is first provided as an extruded profile. This is then processed, as described above, using cutting and forming or bending techniques. This results in a strut brace blank or a strut brace preform in which the main brace and auxiliary brace are spaced parallel to each other and connected via the connecting brace.

[0031] For example, the ends can then be further processed by a bending or pressing operation, and especially by drilling holes to provide mounting points for the strut brace to be installed in the vehicle. Main crossmembers and auxiliary crossmembers can also be bent to create curves or bends around the vehicle's vertical or longitudinal direction. However, a primary direction of the main brace and auxiliary brace, essentially oriented transversely to the vehicle in relation to the installation situation, should be maintained.

[0032] As mentioned at the outset, as an alternative to a strut brace, all of the above, as well as the manufacturing process, can be used to produce a motor vehicle component as a crossmember, in particular a bumper crossmember. The bumper crossmember is then mounted in a substantially vertical orientation when installed in the motor vehicle. The main and auxiliary struts are designed to extend in the motor vehicle with their respective longitudinal directions in the transverse direction.

[0033] The bumper crossmember has a minimum yield strength (Rp 0.2) of 250 MPa. Furthermore, crash boxes are provided, which connect the bumper crossmember to the vehicle, particularly in the area of ​​the front of the vehicle. The crash boxes can, for example, be connected to longitudinal members. The crash boxes themselves are preferably welded to the main strut or auxiliary strut; alternatively, they can also be additionally bolted. The main strut is the one that incorporates the crash boxes. The auxiliary strut, which is designed as a lower auxiliary crossmember, may optionally incorporate additional crash boxes. However, this is not mandatory.

[0034] The hollow chamber connecting struts between the main strut and the auxiliary strut ensure high stiffness of the cross members to each other as well as an increased impact area in the event of a frontal crash with full or partial overlap, especially also in a so-called MPDB crash test.

[0035] Further advantages, features, properties, and aspects of the present invention are the subject of the following description. Preferred embodiments are illustrated in schematic figures. These serve to facilitate understanding of the invention. They show: Fig. 1 a strut according to the invention in perspective view, Fig. 2 the strut according to the invention in top view, Fig. 3a -c each respective cross-section, in particular of the initially provided extruded profile, Fig. 4a +b the provided extruded profile in top view and perspective view, Fig. 5 a further embodiment of the invention, Fig. 6 a further embodiment variant of the strut according to the invention in plan view, Fig. 7 a further embodiment of the present invention, Fig. 8 a further embodiment variant according to the invention, Fig. 9a - c different top views of the longitudinal profile in the transverse direction of the motor vehicle of the main strut, Fig. 10a +b an embodiment of a bumper cross member according to the invention.

[0036] In the figures, the same reference symbols are used for identical or similar components, even if a repeated description or representation of the reference symbols is omitted for the sake of simplicity.

[0037] The previously described and subsequently shown embodiment variants can be combined arbitrarily and individually with each other without leaving the scope of the invention.

[0038] Fig. Figure 1 shows a strut brace 1 according to the invention in a perspective view. The strut brace 1 has a main strut 2 extending in the transverse direction Y of the vehicle when installed. Parallel to this, and in particular offset in the longitudinal direction X of the vehicle, is an auxiliary strut 3. A connecting strut 4 is formed between the main strut 2 and the auxiliary strut 3. The connecting strut 4 is divided into two parts or sections, a first part 4.1 and a second part 4.2. Both parts 4.1 and 4.2 are, however, formed in one piece and from a single material. The first part 4.1 extends obliquely at an angle α between the main strut 2 and the auxiliary strut 3. The second part 4.2 extends in the opposite direction at an angle β, also obliquely between the main strut 2 and the auxiliary strut 3. Angles α and β are preferably equal and are preferably between 10° and 45°, in particular between 12° and 25°, and most preferably between 15° and 20°.

[0039] The in Fig. The strut brace shown in Figure 1 is not yet fully finished. In particular, the ends can be further processed, for example by forming or pressing together, and especially by drilling holes to provide mounting points 8 on a vehicle body.

[0040] In a central area, a central longitudinal section 5 is formed in which the connecting strut 4 runs parallel to the auxiliary strut 3 and, in particular, is integrally and materially connected to the auxiliary strut 3 in this area. End sections 6 are shown in each end area, in which the connecting strut 4 runs parallel to the main strut 2 and is integrally and materially connected in this area. The length sections 5 and 6 are preferably between 2% and 20% of the total length 7 of the strut 1.

[0041] Fig. Figure 2 shows the strut 1 according to the invention in a top view. In contrast to Fig. Figure 1 shows the respective end section already machined. Specifically, connection points or bolting points 8 for application to a motor vehicle (not shown in detail), particularly a vehicle body, are depicted. The ends of the auxiliary strut 3 are not only perforated but also bent. Furthermore, a bolting point 8 is shown on the left side of the image plane. On the right side of the image plane, elongated holes 9 or oval holes are shown. This allows for the compensation of manufacturing tolerances between, in particular, the strut brace 1 and the vehicle body, thus enabling simple initial assembly. Tightening the bolting points 8 and elongated holes 9 (not shown in detail) then provides the necessary torsional rigidity. Due to the elongated holes 9, no further machining is required for installation, especially for initial installation.

[0042] In the middle length section 5, but also in the end length sections 6, a connecting web 10 is formed between the end length sections 6, main strut 2 and connecting web 4, and in the middle length section 5 between connecting web 4 and auxiliary strut 3.

[0043] Fig. 3a and Fig. Figure 3b shows the respective cross-sections, in particular of the initially provided extruded profile. Rectangular hollow chambers 11 and 12 are shown on the outer surface of each cross-section. The left hollow chamber 11, shown on the plane of the image, is larger than the right hollow chamber 12. The left hollow chamber 11 can later be used to form the main strut 2, and the right hollow chamber 12 can then be used to form the auxiliary strut 3. In the case of... Fig. 3a a solid material 13 is shown and in the case of Fig. 3b a hollow profile 14 with a closed cross-section. The individual chambers 11, 12 or hollow profiles 14 are each connected to one another via connecting webs 10. The component is manufactured in one piece and of a uniform material by extrusion and subsequent forming. Fig. Figure 3c shows another embodiment. Here, the left hollow chamber 11 and the right hollow chamber 12 are again designed as rectangular profiles. The hollow profile 14 located between them is connected to the respective rectangular hollow chambers via two double webs 10 each.

[0044] Fig. Figures 4a and 4b show the extruded profile provided in a top and perspective view. The rectangular hollow chambers 11, 12, and the central hollow profile 14 are depicted. Connecting webs 10 are formed between these. It can be seen, however, that the connecting webs 10 have been separated or recessed along their length, thus creating recesses 15. For ease of production, these recesses 15 can be created by simple machining. However, it would also be conceivable, in accordance with the invention, to create the recesses 15 by completely removing the webs in this area.

[0045] Once the blank is prepared in this way, the profiles are created according to the Fig. 5, such that, with regard to the later installation situation, they are pulled away from each other in the longitudinal direction X of the motor vehicle according to the arrows shown, so that in plan view the in Fig. The geometry shown in Figure 5 results. Therefore, the connecting strut 4, formed from the hollow profile 14, is processed using bending techniques. This results in bending zones on the connecting strut, particularly at the transition between the outer and central longitudinal sections 6. In particular, the hollow profile 14 of the subsequent connecting strut 4 could undergo a change in length in the transverse direction Y of the vehicle, relative to its later installation position, as a result of this forming operation. The hollow profile 11 and the hollow profile 12, forming the subsequent main strut 2 and auxiliary strut 3, remain largely unchanged with respect to any change in length.

[0046] Following this process step, further processing steps are carried out, particularly for finishing the end areas. The remaining webs or connecting webs ensure a seamless connection and material uniformity between the later main strut 2 and auxiliary strut 3, as well as connecting strut 4. No further welding operations are necessary, which is particularly advantageous for corresponding aluminum components.

[0047] Fig. Figure 6 shows a further embodiment of the strut brace 1 according to the invention in a top view. Here, the end regions 16 of the auxiliary strut 3 are bent. These rest against the connecting strut 4 and can optionally be welded to it. In a subsequent fastening, for example, only the main strut 2 can then be used to bolt the strut brace 1 according to the invention. The auxiliary strut 3 provides additional torsional stiffness about the vehicle's vertical direction Z.

[0048] Fig. Figure 7 shows a further embodiment of the present invention. Here, a connecting strut 4 is also formed. However, the connecting strut 3 differs from that in the previous version. Fig. 2 is not formed in two parts, but in one part, so that only one diagonal of the connecting strut 4 results. This is preferably then arranged at an angle α between the main strut 2 and the auxiliary strut 3. A respective connecting web 10 then connects the main strut 2 to the connecting strut 4 and the connecting strut 4 to the auxiliary strut 3.

[0049] Another embodiment of the invention is described in Fig. 8a and b are shown. Fig. 8b shows a top view and Fig. 8a a cross-sectional view of an extruded profile for the production of the design variant according to the Fig. 8b. Here, two external rectangular hollow chambers 11, 12 are formed, and two hollow profiles 14 are located between them. The respective hollow chambers 11, 12 and hollow profiles 14 are connected to each other via connecting webs 10. This results in a first connecting strut 4, which is formed in two parts, and a second connecting strut 17, which is connected to the first connecting strut 10. The connecting struts 10, 17 each run at an angle α and β to the main strut 2 and auxiliary strut 3, respectively. In this case, too, the component is manufactured in one piece and from a single material. Additional welding operations, especially of a light metal alloy, particularly an aluminum alloy, can be omitted.

[0050] Fig. Figures 9a to c show various top views of the longitudinal profile of the main strut 2 in the transverse direction of the motor vehicle. This can be seen according to Fig. 9a slightly convex or curved. In particular, the curvature then runs around the vehicle vertical direction Z. The ends can be bent to achieve this.

[0051] Fig. Figure 9b shows a simple design. The longitudinal profile of the main strut 2 is essentially straight. This is easy to manufacture, since the extruded profile does not require further forming work, especially in its end regions.

[0052] Fig. Figure 9c shows a superimposition of main strut 2 and auxiliary strut 3. The end regions of main strut 2 are, for example, according to Fig. 9a is bent, resulting in an overall curvature for the main strut 2. The auxiliary strut 3, on the other hand, runs in a straight line. The connecting strut between them is also present in relation to the previous design variants. Fig. Figure 9c serves to illustrate the longitudinal path of main strut 2 and auxiliary strut 3.

[0053] Fig. Figures 10a and 10b show an embodiment of a bumper crossmember 18 according to the invention. The upper main strut 2 can be arranged as the main crossmember. This is arranged at the top of the vehicle's vertical direction Z. The auxiliary strut 3 is arranged as the lower auxiliary crossmember. The respective ends are bent. The connecting struts 4 according to the invention are arranged between them. The main strut 2 and the auxiliary strut 3 are produced by pulling them apart in parallel, so that the connecting strut 4 located between them is deformed accordingly. The bent ends can then be processed using bending techniques and, for example, also welded or mechanically coupled to mutually stabilize the lateral ends of the upper and lower crossmembers.

[0054] Fig. Figure 10b shows a top view of the bumper crossmember 18 according to the invention. It can be seen that the upper section is arranged according to Fig. 10b, the main crossbeam projecting forward in the longitudinal direction X of the vehicle, acts as the main strut 2 and has a curvature around the vertical direction Z of the vehicle. Below this, located according to Fig. 10a and according to Fig. Located behind 10b, the auxiliary crossmember is arranged as an auxiliary strut 3. The main and auxiliary crossmembers of the bumper crossmember 18 according to the invention are each connected to a motor vehicle (not shown) via crash boxes 19. Connecting struts are arranged between them, extending slightly obliquely in the vertical direction Z of the motor vehicle and connecting the main and auxiliary crossmembers to each other. Reference symbol: 1 Strut 2 Main strut 3 auxiliary strut 4 Connecting strut 4.1 first part of 4 4.2 Part two of 4 5 middle length section 6 end-side length section 7 Total length to 1 8 Screw point 9 elongated holes 10 Connecting bridge 11 Hollow chamber 12 Hollow chamber 13 Solid material 14 Hollow profile 15 recess 16 End to 3 17 second connecting strut 17.1 first part of 17 17.2 second part of 17 18 bumper crossmembers 19 Crashbox X Motor vehicle longitudinal direction Y Motor vehicle transverse direction Z Motor vehicle vertical direction α angle β angle

Claims

[1] Motor vehicle component, in particular strut brace (1) for a motor vehicle or motor vehicle cross member (18), comprising a main strut (2) extending in the transverse direction (Y) of the motor vehicle in the installed position, and an auxiliary strut (3) extending substantially parallel to it in the longitudinal direction (X) of the motor vehicle or offset in the vertical direction (Z) of the motor vehicle, which also extends in the transverse direction (Y) of the motor vehicle, wherein the main strut (2) and the auxiliary strut (3) are connected to each other via at least one connecting strut (4), wherein the main strut (2) and the auxiliary strut (3) are designed in their cross-section as a closed hollow profile (14), characterized by , that the main strut (2), the auxiliary strut (3) and the connecting strut (4) are manufactured in one piece and of the same material and the connecting strut (4) has a round cross-section. [2] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to claim 1, characterized by , that the connecting strut (4) is designed in cross-section as a closed hollow profile (14). [3] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to one of claims 1 or 2, characterized by , that two connecting struts (4) are formed. [4] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to one of the preceding claims, characterized by , that a connecting strut (4) is arranged at an angle between 10 and 45 degrees between the main strut (2) and the auxiliary strut (3). [5] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to one of the preceding claims, characterized by , that the connecting strut (4) runs in two sections at an angle between the main strut (2) and the auxiliary strut (3). [6] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to one of the preceding claims, characterized by , that in an outer length section between 4% and 25% of the total length (7) the connecting strut (4) runs parallel to the main strut (2). [7] Motor vehicle component, in particular strut brace (1) or motor vehicle cross member (18) according to any of the preceding claims, characterized by , that in a middle length section (5) between 4% and 25% of the total length (7) the connecting strut (4) runs parallel to the auxiliary strut (3). [8] Motor vehicle component, in particular strut brace (1) according to one of the preceding claims, characterized by that the main strut (2) and / or the auxiliary strut (3) are configured in a rectangular cross-section or in a round cross-section. [9] Motor vehicle component, in particular strut brace (1) according to one of the preceding claims, characterized by, that the main strut (2) and the connecting strut (4) and the connecting strut (4) and the auxiliary strut (3) are connected at least in sections along their length in cross-section via a connecting web (10). [10] Method for manufacturing a motor vehicle component, in particular a strut brace (1) for a motor vehicle, having the features of claim 1, characterized by the following steps: • Providing an extruded profile which has a hollow chamber (11, 12) on the outside in cross-section and a solid material (13) or a third hollow chamber in the middle, wherein the hollow chambers (11, 12) are connected to the solid material (13) or the middle hollow chamber (12) in cross-section via a connecting web (17), • Separating the connecting webs section by section (17), • Pulling apart the outer hollow chambers (11, 12) such that a main strut (2) is formed by a first hollow chamber (11) and, parallel to it and spaced apart, an auxiliary strut (3) is formed by a second hollow chamber (12) and the solid material (13) or the middle hollow chamber (12) forms a connecting strut (17) which connects the main strut (2) and the auxiliary strut (3) in one piece and with a uniform material. • Optional further processing, in particular forming and / or punching and / or trimming of the motor vehicle component produced in this way, in particular strut brace (1).

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