Crash management system for a motor vehicle in metal-plastic hybrid construction and method for its manufacture

Abstract

The invention relates to a crash management system (100) for a motor vehicle, with - several elongated metal profile elements (110) arranged adjacent to each other, and - several injection-molded connecting sections (120, 130) made of plastic, which are positively connected to the profile elements (110) in axial areas and are designed to fix the profile elements (110) locally relative to each other. In addition, one of the connecting sections (120, 130) has a receptacle designed as a metal element (150) and embedded in the plastic for attaching a towing eye, wherein a weld or an undercut is provided between the metal element (150) and at least one of the profile elements (110) for the purpose of transmitting tensile force. The invention further relates to a method for manufacturing such a crash management system (100).

Description

[0001] The invention relates to a so-called crash management system for a motor vehicle according to the preamble of patent claim 1. The invention further relates to a method for producing such a crash management system according to the preamble of patent claim 9.

[0002] A crash management system (CMS) is designed to absorb the crash energy acting on a motor vehicle in the event of a crash, to reduce it through deformation work if a certain energy level is exceeded and to transfer it to the body structure.

[0003] From DE 10 2021 130 442 B3 a crash management system for a motor vehicle is known, with - a plurality of preformed, elongated hollow profile elements made of a first, fiber-reinforced plastic material, which are arranged adjacent to one another; - a plurality of connecting sections made of a second plastic material, which are integrally connected to the hollow profile elements and are designed to fix the plurality of hollow profile elements locally relative to one another; - a plurality of crash box elements made of the second plastic material, wherein each crash box element is formed integrally with at least one of the connecting sections.

[0004] DE 10 2021 130 442 B3 further describes a method for producing the crash management system, comprising the steps: - producing and providing a plurality of elongated, substantially straight hollow profile elements made of a first, fiber-reinforced plastic material; - Forming the elongated hollow profile elements into curved hollow profile elements; - Arranging the curved hollow profile elements in an injection molding tool; - Injecting injection molding compound made of a second plastic material at several positions along the hollow profile elements in order to locally connect the hollow profile elements to one another to form connecting sections, wherein at least during the injection of the injection molding compound a counterpressure is generated in the cavities of the hollow profile elements by means of fluid introduced under pressure.

[0005] The closest document DE 10 2015 121 021 A1 describes a bumper unit of a vehicle and a method for manufacturing the same. Unlike the aforementioned prior art, the profile elements referred to as bumper beams can be formed from a metal, namely high-strength steel. A connecting portion referred to as a bumper reinforcement element can be formed by injection molding by inserting the bumper beams into a mold and injecting a synthetic resin (e.g., plastic and / or polymer) around the outer surface of the bumper beams.

[0006] Regarding the state of the art, reference is also made to DE 10 2016 200 674 A1, KR 10 2015 0 129 204 A and KR 10 2018 0 098 981 A.

[0007] The invention is based on the object of providing an improved and comparatively easy-to-manufacture crash management system.

[0008] This object is achieved by the inventive crash management system of patent claim 1 and by the inventive crash management system of patent claim 2. With the independent patent claim 9, the invention also extends to a method for manufacturing. Additional features of the invention are evident analogously for all subject matter of the invention from the dependent patent claims, the following description of the invention (this expressly includes features described optionally and by way of example), and the figures.

[0009] The crash management system according to the invention comprises - several, ie at least two, elongated profile elements made of metal, which are arranged adjacent and in particular substantially parallel to one another, and - several, i.e. at least two, connecting sections made of plastic produced by injection moulding, which are positively connected in axial regions to the (several) profile elements and which are designed to fix the (several) profile elements locally relative to one another.

[0010] The crash management system according to the invention is preferably a front crash management system for the front area of ​​a motor vehicle or a rear crash management system for the rear area of ​​a motor vehicle, which is designed in particular for crash energy acting at least approximately frontally on the front or rear area. The crash management system according to the invention is preferably designed as a single piece, i.e., as a non-disassemblable component. The crash management system according to the invention has a metal-plastic hybrid construction, as explained below.

[0011] In the crash management system, the profile elements are made of metal, which is comparatively stable, especially compared to hollow profile elements made of plastic, and has a high crash energy absorption capacity. The profile elements can also be referred to as metallic profile elements or metal profile elements. The connection sections can be created without counter or internal pressure, especially when using hollow profile elements (see below), which simplifies production.

[0012] The profile elements can be designed as solid material profile elements or, preferably, as hollow profile elements. The profile elements are preferably made of magnesium (or a magnesium alloy), aluminum (or an aluminum alloy), or steel. The profile elements can have a round cross-section, in particular a circular cross-section, or a polygonal cross-section, in particular a rectangular cross-section, in particular with an outer diameter (or a comparable outer dimension) of 40 mm to 60 mm. The profile elements can be essentially straight or curved or bent at least in sections. The profile elements are preferably produced from a semi-finished rod, e.g. a tube, with further forming optionally taking place after cutting to length. The profile elements are elongated, which means that they have an axial longitudinal extent that is a multiple of the outer diameter. The profile elements can, for example,have an axial length of 800 mm to 1200 mm. Preferably, all profile elements of the crash management system are identical. However, the profile elements can also be different.

[0013] In the crash management system, the profile elements are secured to one another by so-called connecting sections. The connecting sections are made of plastic or plastic material and produced by injection molding, in particular by direct injection molding onto the profile elements. The connecting sections are positively connected to the profile elements in axial regions (meaning axial longitudinal sections of the profile elements), in particular in such a way that the profile elements are completely enclosed or framed by the plastic in the relevant axial regions.

[0014] The connecting sections are preferably formed from a thermoplastic (e.g. PP or PA), in particular a fiber-filled thermoplastic (e.g. PP-GF or PA6-GF).

[0015] The crash management system can have a plurality of, i.e. at least two and in particular exactly two, crash box elements made of plastic and produced by injection molding. Each of these crash box elements is connected to one of the connecting sections. In other words, at least two of the connecting sections each have a crash box element (produced by injection molding and made of plastic) connected to it. Thus, the same number of connecting sections and crash box elements or more connecting sections than crash box elements can be provided. The crash box elements are provided to absorb crash energy. The crash box elements also serve, in particular, to connect the crash management system to the vehicle body, in particular to longitudinal members of the vehicle body.

[0016] The crash box elements are preferably made of a thermoplastic (e.g., PP or PA), in particular a fiber-filled thermoplastic (e.g., PP-GF or PA6-GF). The crash box elements are preferably made of the same plastic as the connecting sections.

[0017] The crashbox elements can be manufactured as separate components and joined to the respective connecting sections by screwing, welding, gluing, or the like. However, it is preferably provided that each crashbox element is formed integrally with one of the connecting sections. This means, in particular, that the crashbox elements are injection-molded onto the respective connecting sections or are produced together with the connecting sections in the same process step. The integral formation of a connecting section and a crashbox element can also be referred to as an injection-molding unit or injection-molding module.

[0018] The crash box elements preferably have a honeycomb structure oriented transversely to the intended crash loading direction. This means that the honeycombs of such a honeycomb structure extend transversely to the direction of force application of an assumed or expected crash. In a front or rear crash management system, the honeycombs would therefore be aligned substantially in the vehicle transverse direction (y-direction of the vehicle coordinate system). The honeycombs of the honeycomb structure preferably have a diamond-shaped and / or triangular contour, which is formed by a corresponding rib structure. In addition, the crash box elements can have a wall surrounding the honeycomb structure and / or connecting flanges. Furthermore, it is preferably provided that the honeycomb structure (of the crash box elements) extends counter to the intended crash loading direction, i.e. in the direction of the profile elements, with decreasing stiffness or in the loading direction, i.e.in a direction away from the profile elements, with increasing stiffness. This results in a gradual failure of the honeycomb structure in the event of a crash, beginning at the end closest to the profile elements (i.e., the end facing the profile elements). Decreasing stiffness is achieved, in particular, by increasing honeycomb sizes and / or by decreasing, in particular continuously decreasing, wall thickness of the rib structure, and vice versa.

[0019] According to the invention, at least one of the connecting sections, in particular a connecting section formed integrally with a crash box element, is provided with or has a receptacle formed as a metal element and embedded in the plastic for attaching a towing eye or the like. The metal element can have a threaded bushing or the like for detachable attachment of the towing eye. One of the profile elements can be formed with a bore or opening into which the metal element is inserted, with a weld or undercut being provided between the metal element and the profile element for the purpose of transmitting tensile force. Alternatively, the metal element can also be arranged between two profile elements which are provided with recesses or indentations at the relevant location to create a passage or opening.a clearance, wherein a weld or an undercut is provided between the metal element and at least one of the profile elements for the purpose of transmitting tensile force.

[0020] The method according to the invention for producing the crash management system comprises at least the following steps: - Providing the profile elements, if necessary forming the profile elements, and arranging the profile elements with the intended relative position in an injection molding tool; - Injection moulding of the connecting sections, in particular by directly injecting the plastic onto the profile elements, and, if necessary, injection moulding of the crash box elements; - Demoulding of the crash management system (after curing or cooling of the plastic).

[0021] The profile elements are preferably hollow profile elements. Injection molding of the connecting sections can then be carried out without counterpressure or internal pressure, since the metal profile elements can withstand high injection pressures, even with thin walls, especially if they have a round or circular cross-section. In principle, however, injection molding can also be carried out with counterpressure or internal pressure.

[0022] Regarding the mount for attaching a towing eye, the metal element intended for this purpose is positioned on one of the profile elements or between two profile elements before injection molding, as described above, if necessary after appropriate preparation of the respective profile element(s). Welding may also be performed if necessary. During injection molding, the metal element is then overmolded with plastic and embedded in the plastic, providing additional stabilization.

[0023] Within the scope of the invention, both the features described above and those explained below are applicable not only in the respective combination of features specified, but also in other combinations of features or in isolation. This also applies to the features shown in the figures.

[0024] The invention is explained in more detail below in a non-limiting manner with reference to the figures. Fig. 1 shows a crash management system according to the invention designed in metal-plastic hybrid construction. Fig. 2 shows the crash management system of the Fig. 1 in a top view. Fig. 3 shows a first possible embodiment for arranging a receptacle for attaching a towing eye to the crash management system of the Fig. 1. Fig. 4 shows analogous to Fig. 3 a second possible embodiment for arranging the recording.

[0025] In the Fig. The crash management system 100 shown in Figure 1 is, by way of example, a front crash management system for the front area of ​​a motor vehicle. The crash management system 100 is designed for at least approximately frontal impact of the crash energy or crash load, which is illustrated non-limitingly by the arrow E.

[0026] The crash management system 100 comprises a plurality of elongated profile elements 110 made of metal, which are arranged adjacent to one another, and a plurality of injection-molded connecting sections 120, 130 made of plastic, which are positively connected to the profile elements 110 in axial regions and are configured to locally fix the plurality of profile elements 110 relative to one another. The slightly curved profile elements 110 are designed as tubular or hollow-cylindrical hollow profile elements. The profile elements 110 extend in the vehicle transverse direction (y-direction of the vehicle coordinate system) and are arranged one above the other with a parallel alignment in the vehicle vertical direction (z-direction of the vehicle coordinate system). There are two outer connecting sections 130 and a central connecting section 120. The crash management system 100 can also comprise a different number of profile elements 110 and / or connecting sections 120, 130.

[0027] The crash management system 100 further comprises two crash box elements 140, which are arranged behind the outer connecting sections 130 in the vehicle longitudinal direction (x-direction of the vehicle coordinate system) and are formed integrally with them. The crash box elements 140 have a honeycomb structure 141 oriented transversely to the intended crash loading direction (see arrow E), i.e., in the vehicle transverse direction (y-direction of the vehicle coordinate system). The honeycomb structures 141 can be configured with decreasing rigidity, counter to the intended crash loading direction, i.e., forward toward the profile elements 110, as explained above. The crash box elements 140 further comprise connecting flanges 142 for connecting the crash management system 100 to the vehicle body.

[0028] Furthermore, one of the outer connecting sections 130 features a receptacle 150, formed as a metal element and embedded in the plastic, for the releasable attachment of a towing eye or the like. The receptacle 150 is located in front of the crash box element 140, which is formed integrally with the respective connecting section 130 and can thus also function as a force flow mediator between the towing eye and the vehicle body.

[0029] Fig. Figure 2 shows the crash management system 100 in a top view. The double arrows S indicate the movements of the tool slides of an injection molding tool. During the manufacture of the crash management system 100 (as described above), the integral formation of the connecting sections 130 and crash box elements 140 with the honeycomb structures 141 can be realized using such tool slides.

[0030] A preferred arrangement of the receptacle 150 designed as a metal element for the attachment of a towing eye is shown in Fig. 3. One of the profile elements 110 is formed with a bore or opening into which the metal element or receptacle 150 is inserted. To transmit tensile forces, a weld 151 and / or an undercut 152 may be provided.

[0031] Another preferred arrangement of the receptacle 150 formed as a metal element is shown in Fig. 4. The metal element or the receptacle 150 is arranged here between two profile elements 110, which are formed with recesses or indentations 111 at the relevant location. To transmit tensile forces, a weld and / or an undercut can also be provided here.

Claims

[1] Crash management system (100) for a motor vehicle, comprising - a plurality of elongated profile elements (110) made of metal, which are arranged adjacent to one another, and - a plurality of connecting sections (120, 130) made of plastic produced by injection moulding, which are positively connected to the profile elements (110) in axial regions and are designed to fix the profile elements (110) locally relative to one another, characterized by , that on one of the connecting sections (120, 130) there is a receptacle designed as a metal element (150) and embedded in the plastic for attaching a towing eye, wherein one of the profile elements (110) is formed with a bore into which the metal element (150) is inserted, wherein a weld (151) or an undercut (152) is provided between the metal element (150) and the profile element (110) for the purpose of transmitting tensile force. [2] Crash management system (100) for a motor vehicle, comprising - a plurality of elongated profile elements (110) made of metal, which are arranged adjacent to one another, and - a plurality of connecting sections (120, 130) made of plastic produced by injection moulding, which are positively connected to the profile elements (110) in axial regions and are designed to fix the profile elements (110) locally relative to one another, characterized by , that on one of the connecting sections (120, 130) there is a receptacle designed as a metal element (150) and embedded in the plastic for fastening a towing eye, wherein the metal element (150) is arranged between two profile elements (110) which are designed with recesses or impressions (111) at the relevant point to create a passage, wherein a weld or an undercut is provided between the metal element (150) and at least one of the profile elements (110) for the purpose of transmitting tensile force. [3] Crash management system (100) according to claim 1 or 2, characterized by that the profile elements (110) are hollow profile elements. [4] Crash management system (100) according to one of the preceding claims, with - a plurality of injection-molded crash box elements (140) made of plastic, each crash box element (140) being connected to one of the connecting sections (130). [5] Crash management system (100) according to claim 4, characterized by that each crash box element (140) is formed integrally with one of the connecting sections (130). [6] Crash management system (100) according to claim 4 or 5, characterized by that the crash box elements (140) have a honeycomb structure (141) oriented transversely to the intended crash loading direction (E). [7] Crash management system (100) according to claim 6, characterized by that the honeycomb structure (141) is designed with decreasing rigidity opposite to the intended crash load direction (E). [8] Crash management system (100) according to one of claims 5 to 7, characterized by that the receptacle designed as a metal element (150) for fastening a towing eye is arranged on a connecting section (130) formed in one piece with a crash box element (140). [9] Method for producing a crash management system (100) according to one of the preceding claims, comprising the following steps: - Providing the profile elements (110) and arranging the profile elements (110) with the intended relative position in an injection molding tool; - injection molding of the connecting sections (120, 130); - demoulding of the crash management system (100); characterized by that before injection molding, the metal element (150) provided as a receptacle for attaching a towing eye is arranged on the relevant profile element (110) or between the two relevant profile elements (110) after appropriate preparation of the relevant profile element (110) or the relevant profile elements (110) and, if necessary, a welding (151) is also carried out, and that during injection molding, the metal element (150) is then overmolded with plastic and embedded in the plastic.

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