COMPONENT PROVIDED FOR ENERGY ABSORPTION

Abstract

The proposed solution relates to a component that is provided for energy absorption in the event of a force (F) acting on the component (1).

The component (1) is configured with a component structure (10) integrating at least one first energy absorption mechanism and at least one second energy absorption mechanism, by means of which the first and second energy absorption mechanisms can be activated in the event of a force acting on the component (1) and exceeding a threshold value.

Claims

1. A component that is provided for energy absorption in the event of a force (F) acting on the component (1), characterized in that the component (1) is formed with a component structure (10) integrating at least one first energy absorption mechanism and at least one second energy absorption mechanism, with which the first and second energy absorption mechanisms can be activated in the event of a force acting on the component (1) and exceeding a threshold value.

2. The component according to claim 1, characterized in that in the event of a force acting on the component (1) and exceeding a threshold value, the first and second energy absorption mechanisms can be activated in time succession by means of the component structure (10), so that at least part of the energy introduced into the component (1) via the acting force (F) is absorbed via the first energy absorption mechanism before the at least one second energy absorption mechanism is activated.

3. The component according to claim 1 or 2, characterized in that an activation of at least one of the first and second energy absorption mechanisms requires a plastic deformation of at least one portion of the component structure (10).

4. The component according to claim 3, characterized in that at least one of the first and second energy absorption mechanisms defines breaking points (120a, 120b; 14a, 14b) within the component structure (10) for one fracture or several fractures, in particular one shear fracture or several shear fractures.

5. The component according to claim 4, characterized in that at least one breaking point (120a, 120b; 14a, 14b) is provided at a region (120; 14) of the component structure (10) bordering at least one cutout (12, 13) in the component structure (10).

6. The component according to claim 5, characterized in that the bordering area (120; 14) is present between two cutouts (12; 13) in the component structure (10), so that, in the event of a force exceeding the threshold value and acting on the component (1), a shear fracture occurring at the at least one breaking point (120a, 120b, 14a, 14b) extends between the two cutouts (12; 13) and leads to a connection of the two cutouts.

7. The component according to claim 5 or 6, characterized in that the cutout (12, 13) is elliptical, in particular circular, hexagonal, in particular honeycomb-shaped, or octagonal in cross-section.

8. The component according to any of the preceding claims, characterized in that one of the first and second energy absorption mechanisms comprises an interface (12.1, 12.2) within the component structure (10) for an energy-absorbing positive and/or non-positive connection when a force (F) exceeding the threshold value is applied onto the component (1).

9. The component according to claim 8, characterized in that the second energy absorption mechanism comprises the interface (12.1, 12.2) and the first energy absorption mechanism defines at least one first contact area to be brought in contact with the interface (12.1,12.2) at least partly by positive and/or non-positive engagement in the event of a force exceeding the threshold value and acting on the component (1).

10. The component according to claim 9, characterized in that the interface is formed by at least one second contact area (12.1, 12.2) at least partly recessed with respect to an adjacent area (120) of the component structure (10), in which at least part of the first contact area (120) can engage in the event of a force exceeding the threshold value and acting on the component (1) and by plastic deformation of at least one portion of the component (1).

11. The component according to any of claims 4 to 7 and any of claim 9 or 10, characterized in that the first contact area (120) includes at least one of the breaking points (120a, 120b) for a shear fracture.

12. The component according to claim 11, characterized in that the first contact area (120) in the component structure (10) is configured and dimensioned in such a way that, in the event of a force (F) exceeding the threshold value and acting on the component (1), at least one shear fracture appears at the first contact area (120) and a shear fracture surface (120.1, 120.2) protruding with respect to the adjacent second contact area (12.1, 12.2) is obtained, which is brought into positive and/or non-positive contact with the second contact area (12.1, 12.2) when the force (F) continues to act on the component (1).

13. The component according to claim 5 and claim 12, characterized in that the second contact area (12.1, 12.2) comprises a shell surface of a cutout (12).

14. The component according to claim 13, characterized in that the first contact area (120) is formed by a partition wall between two cutouts (12), which extends along a spatial direction (y) with a wall length (l.sub.1), wherein the wall length (l.sub.2) is less than a cutout length (l.sub.2) with which each of the two cutouts (12) extends along the same spatial direction (y).

15. The component according to any of the preceding claims, characterized in that the component structure (10) is formed lattice-shaped.

16. The component according to claim 15, characterized in that the lattice-shaped component structure (10) extends along three mutually perpendicular spatial directions (x, y, z), wherein in two mutually perpendicular cross-sectional views a lattice structure each is formed with cutouts (11, 12, 13) arranged in a pattern and the cutouts (12, 13) of two cross-sectional views are different.

17. The component according to claim 16, characterized in that the cutouts (12, 13) of two cross-sectional views differ from each other in terms of their dimensions and/or in terms of their respective geometric shape.

18. The component according to claim 17, characterized in that cutouts (12) of a first cross-sectional view are each hexagonal and cutouts (13) of a second cross-sectional view perpendicular to the first cross-sectional view are each octagonal.

19. The component according to any one of claims 16 to 18, characterized in that, in a cross-sectional view, four cutouts (13) are distributed around a support portion (15) of the lattice-shaped component structure (10), wherein the support portion (15) is located at a crossing point of partition walls bordering the cutouts (13), and the support portion (15) has a larger moment of resistance than each of the four partition walls (120).

20. The component according to any of claims 15 to 19, characterized in that the lattice-shaped component structure (10) is based on at least one lattice made up of identical elementary cells (100), in which the geometry, dimension, thickness of webs each bordering an elementary cell (100) and/or a volumetric filling ratio are predetermined on the basis of a reference cell (100R) in dependence on an intended use, a portion of the component (1) to be formed therewith and/or forces (F) acting on the component (1) in a properly mounted state.

21. An assembly for a vehicle interior space including a component according to any of the preceding claims.

22. A vehicle seat comprising a component according to any of claims 1 to 20.

23. A vehicle door comprising a component according to any of claims 1 to 20.

Description

[0027] The attached Figures by way of example illustrate possible design variants of the proposed solution.

[0028] In the drawings:

[0029] FIGS. 1A-1F show a design variant of a proposed component loaded in the event of a force exceeding a threshold value, which acts on the component as a bending force and leads to the activation of different energy absorption mechanisms within the component, before failure of the component occurs;

[0030] FIGS. 2A-2B show different views of a development of the component of FIGS. 1A to 1F with differently designed lattice-shaped component structures;

[0031] FIG. 3 sectionally and in a side view shows another design variant of a proposed component with a Y-shaped end portion formed by a lattice-shaped component structure;

[0032] FIG. 4 sectionally shows another design variant of a proposed component with an O-shaped portion on which a lattice-shaped component structure is provided;

[0033] FIGS. 5A-5B show another design variant of a proposed component, which is configured as an armor steel plate with a lattice-shaped component structure, in two different phases on bombardment with a projectile;

[0034] FIGS. 6A-6D each sectionally show a design variant of a proposed component with a lattice-shaped component structure made up of elementary cells, wherein in FIGS. 6A to 6D dimensions, web thicknesses and volumetric filling ratios of the elementary cells are varied so that the lattice-shaped component structures are designed for different force-path characteristic curves;

[0035] FIG. 7 shows a force-path diagram with an illustration of different characteristic curves for the design of a lattice-shaped component structure of FIGS. 6A to 6D;

[0036] FIG. 8 sectionally shows a lattice-shaped component structure by highlighting a reference cell for the construction of the lattice-shaped component structure.

[0037] FIGS. 1A to 1F schematically show a design variant of a proposed component 1 that is loaded with a force F. In the present case, the force F by way of example is a bending force that leads to a moment on the component 1 around a bearing point L at which the component 1 is fixed. The component 1 for example can be a component for a vehicle, for example for a vehicle seat, and form a crash absorber. Such crash absorbers are designed in particular for occurring crash cases and associated excessive loads in order to specifically absorb (crash) energy. In the present case, the component 1 therefore integrates several (at least two) energy absorption mechanisms based on different action principles, which can be activated in the event of the force F acting on the component 1 and exceeding a threshold value and only permit failure of the component 1 when the component 1 has absorbed a comparatively large amount of energy.

[0038] In the present case, the component 1 therefor is configured with a lattice-shaped component structure 10 and extends along three mutually perpendicular spatial directions x, y and z. Due to the lattice-shaped component structure 10 of the component 1, a lattice structure formed of a pattern of cutouts 11, 12 or 13 uniformly distributed here is formed in each of three mutually perpendicular cross-sectional views, i.e. in an xy-plane, an xz-plane and a yz-plane. The lattice-shaped component structure 10 with the cutouts 11, 12 and 13, which in FIGS. 1A to 1F by way of example each are elliptical in cross-section, is shaped and dimensioned such that in the event of the force F exceeding the threshold value and acting on the component 1, for example as a result of a crash, interlinked, temporally successive energy absorption mechanisms are activated within the lattice-shaped component structure 10 in order to absorb at least part of the (crash) energy introduced into the component 1 by the force F.

[0039] In the illustrated design variant, the force F in FIG. 1A acts along the direction −z and due to its height exceeding the threshold value initially leads to a plastic deformation of the component 1, by which part of the energy is absorbed already. The cutouts 12 visible in a cross-sectional view along the yz-plane are dimensioned and separated from each other in the y-direction via partition walls 120 acting as first contact areas in such a way that in the area along the shell surface of the cutouts 12 located in the y-direction the largest inherent tensions are present and hence (predetermined) breaking points 120a, 120b are defined. Under the applied force F and shear forces resulting therefrom cracks are formed at these breaking points, which then grow towards a respectively adjacent cutout 12 and hence primarily in the direction y or −y (cf. FIG. 1B). Due to the dimensioning of the lattice-shaped component structure 10, breaking points 120a, 120b thus are specifically provided in the vicinity of the partition walls 120, along which a crack starts to form due to the force F (FIG. 1C), which with a continued force F leads to shear bridges 121 of the partition walls 120 due to resulting shear forces (FIG. 1D).

[0040] A first energy absorption mechanism of the component F thus is formed by the combination of the cutouts 12 and partition walls 120 and the breaking points 120a and 120b provided on the same. As a result of the force F exceeding the threshold value and acting on the component 1, this combination and corresponding design of the lattice-shaped component structure 10 permits a plastic deformation of the component 1 not only for energy absorption. Rather, the occurring plastic deformation of the component 1 also is utilized for activating the first energy absorption mechanism based on another action principle, for which a formation of shear fractures 121 is decisive in order to absorb energy in the component 1, without the component 1 failing completely.

[0041] A second energy absorption mechanism is connected in series with the first energy absorption mechanism of the component 1. This second energy absorption mechanism utilizes the shear surfaces 120.1 and 120.2 formed by a shear fracture 121 on an original partition wall 120 (cf. FIGS. 1D and 1E) for providing a positive and/or non-positive connection additionally absorbing energy within the component structure 10. In addition to a partition wall 120 acting as a first contact area, two second contact areas 12.1 and 12.2 form part of the second energy absorption mechanism, which are formed by shell surfaces of an adjacent cutout 12. Each part of a shell surface of a cutout 12, which adjoins a resulting shear surface 120.1 or 120.2 along the spatial direction y, acts as a second contact area 12.1 and 12.2 of the second energy absorption mechanism, with which an opposite adjacent shear surface 120.1, 120.2 can be brought in contact by positive and/or non-positive engagement, when the component 1 continues to be loaded with the (bending) force F. Thus, two structural parts 10a and 10b shearing off on each other are formed within the component structure 10 due to the shear fractures 121. Consequently, the shear fractures 121 lead to the connection of individual cutouts 12 to each other. When the resulting structural parts 10a, 10b continue to shear off, the structural parts 10a, 10b can get entangled with each other upon displacement relative to each other. The parts of the original partition wall 120 having the shear surfaces 120.1, 120.2 then alternately dip into the recessed areas of the cutouts 12 and form a positive and/or non-positive connection which provides an additional force of resistance to the force F. Furthermore, cutouts 12 and partition walls 120 in the lattice-shaped component structure 10 can also be dimensioned in such a way that with a persistently applied force F—and an associated further shearing of the structural parts 10a and 10b-skipping occurs of the tooth-like protruding parts of the (broken/cracked) partition walls 120 forming the shear surfaces 120.1 and 120.2 into recessed areas of the original cutouts 12 adjacent along the y-direction.

[0042] Only after no more energy can be absorbed by the second energy absorption mechanism, which is provided downstream and thus connected in series with the first energy absorption mechanism, and thus the force F on the component 1 continues to be maintained, does the component 1 fail via a failure crack V in an area close to the bearing corresponding to FIG. 1F.

[0043] Due to the design of the component structure 11 a plurality of energy absorption mechanisms are connected in series, whereby the effectivity for an absorption of a force F applied from outside has increased significantly as compared to conventional component structures. In the design of the (lattice-shaped) component structure 10, different failure stages can be predetermined and be controlled specifically, and in particular the component structure 1 can be designed specifically for different load directions.

[0044] FIGS. 2A and 2B show further details of a lattice-shaped component structure 10 for a component 1 of FIGS. 1A to 1F. FIGS. 2A and 2B in particular show different patterns for lattices underlying the component structure 10 in mutually perpendicular cross-sectional views. While the cutouts 12 each are of hexagonal shape in the yz-plane, the cutouts 13 which in a top view are disposed along the y or −y direction and hence lie in an xz-plane each are geometrically dissimilar and octagonal. Moreover, the thicknesses of the (web-shaped) partition walls 120 or 14 located between the individual cutouts 12 and 13 also are different.

[0045] The different geometrical configuration of the lattice-shaped component structure 10 in the different mutually perpendicular cross-sectional views in particular results from the integration of the different energy absorption mechanisms into the component structure 10, which is useful to specifically control the plastic deformations obtained under a load that is caused by a force applied onto the component 1 from outside, and to control the shear forces introduced into the component structure 10. For example, support portions 15 of the lattice-shaped component structure 10, which in a cross-sectional view located in the xz-plane lie in a crossing point of four partition walls, are uniformly distributed around the four cutouts 13, are formed with a greater supporting cross-section and hence a greater moment of resistance than the adjacent, intersecting partition walls 14. It hence is ensured that in the event of a (bending) force acting on the component 1 and its lattice-shaped component structure 10 along the z-direction, a plastic deformation does not lead to a shear fracture 121 in the support portion 15, but in an adjacent partition wall 14.

[0046] To specifically influence the fracture tendency of the partition wall 14 as well as the location and course of a fracture, waisting for example is provided approximately centrally on each partition wall 14, which approximately centrally leads to a reduced wall thickness and hence results in an indentation extending in the y-direction. On an area of reduced wall thickness, breaking points 14a and 14b are specifically defined in this way along the indentations for a shear fracture.

[0047] Furthermore, in order to support the formation of an energy-absorbing positive and/or non-positive connection and the entanglement of the structural parts 10a, 10b at the contact areas 120 and 12.1, 12.2 during the shearing of two structural parts 10a and 10b formed by shear fractures, which is described with FIGS. 1A to 1F. (cutout) lengths l.sub.2—measured in the y-direction—of the cutouts 12 following each other in the y-direction are chosen greater than (wall) lengths l.sub.1 of a partition wall 120 provided between two cutouts 12 in each case.

[0048] An angle α of a flank defined in the circumference of each hexagonal cutout 12 can also be used to control the extent to which, after a shear fracture, an additional and possibly repeated (at least two times) skipping of the parts of a fractured partition wall 120 having the shear surfaces 120.1 and 120.2 and of the second contact areas 12.1 and 12.2 defined by the cutouts 12 occurs. The (flank) angle α defines an inclination of a flank at a cutout 12 with respect to the spatial direction y, wherein this flank extends along an edge of the hexagonal basic shape of a cutout 12 shown in the yz-plane and opens at a breaking point 120a or 120b. Hence, on appearance of a shear fracture 121 a shear surface 120.1, 120.2 can slide into the opposite part of the adjacent cutout 12 along the corresponding flank.

[0049] When the second energy absorption mechanism is active via the interlocking structural parts 10a, 10b shearing off, an additional resistance force is added to a resistance force counteracting the deformation of the component 1 and applied by the support portions 15 due to the overlapping, interlocking structural parts 10a, 10b. In this way, the final strength at least temporarily is significantly increased until the failure crack V appears.

[0050] The principle underlying the exemplary embodiments of FIGS. 1A to 1F ultimately is independent of the geometry of the component 1. For example, the proposed principle can also be used for a component 1 of FIG. 3. Here, the component 1 with a lattice-shaped component structure 10 is formed on an end portion that is Y-shaped in FIG. 3. The end portion of the component 1 hence has two component arms 10.1 and 10.2 extended at an angle to each other, which protrude from a common component base 10.3. Both in the component arms 10.1 and 10.2 and in the component base 10.3, successive cutouts 12 corresponding to the design variants of FIGS. 1A to 2B are provided along a respective direction of extension. On the partition walls 120 between these cutouts 12, (predetermined) breaking points 120a, 120b again are specifically provided for a defined crack formation and a defined crack growth. The design of the underlying lattice correspondingly is chosen such that shear fractures 121 are formed in the partition walls 120 in such a way that adjacent cutouts 12 thereby are connected to each other under plastic deformation of the component 1.

[0051] The same applies for a design variant corresponding to FIG. 4. Here, the component 1 by way of example is provided with an O-shaped component opening 10.0 which is circumferentially bordered by two mutually opposite component arms 10.1 and 10.2. These component arms 10.1, 10.2 as well as the adjoining areas of the component structure 10 of the component 1 also are each formed as a lattice with a plurality of cutouts 12 and with (web-shaped) partition walls 120 provided with breaking points 120a, 120b.

[0052] FIGS. 5A and 5B show the utilization of a component structure 10 in an energy-absorbing component 1, which is configured as an armor steel plate. Here, a force exceeding a threshold value acts on the component 1 via a projectile G. As a result of the force of the projectile G, the component 1 is plastically deformed at a bending or buckling point B. Again, as a result of the plastic deformation occurring along successive partition walls 120 and cutouts 12 of a lattice-shaped component structure 10, a multitude of energy-absorbing shear fractures 121 are permitted without complete failure of the component 1. Structural parts shearing off on each other and hence fragments of the component 1 continue to be held in place and the armor plate can withstand further bombardment.

[0053] FIGS. 6A, 6B, 6C and 6D show another exemplary embodiment of a component 1 with a differently designed lattice-shaped component structure 10. The component 1 here can integrate the energy absorption mechanisms explained in connection with FIGS. 1A to 5B. For a simplified and use-related adaptation of the lattice-shaped component structure 10 in connection with a design preceding the manufacture, the lattice-shaped component structure 10 is made up of lattices with identically designed elementary cells 100. Each elementary cell 100 originates from a reference cell 100R underlying all component structures of FIGS. 6A to 6D, which is varied merely in dependence on certain component parameters. In the final analysis, each component 1 of FIGS. 6A to 6D is adapted for different requirements merely via adaptations of the elementary cells and of a lattice formed therewith, without the dimensions of component 1 and its outer contour having to be different. In particular, by varying an elementary cell 100 and a lattice of the component structure 10 formed therewith, a simple design can be achieved on different characteristic curves.

[0054] A relevant characteristic curve with different areas here is shown with reference to FIG. 7. The characteristic curve f indicates the degree of a deformation s of a component 1 in dependence on a force F until failure. In different areas I, II and III the characteristic curve has different slopes. The individual areas I, II and III can correspond for example to the requirements for different utilization scenarios of a seat component formed with the component 1. The course of the characteristic curve in the area I is provided for a seat component typically carrying a child, the characteristic curve in the area II is provided for a seat component carrying a “lightweight” adult (50th percentile of the weight), and the characteristic curve in the area III is provided for a seat component carrying a “heavy” adult (95th percentile of the weight). Depending on the desired characteristic curve or characteristic curve area I, II, III, the lattice-shaped component structure 10 can be varied by varying the respective elementary cells 100 and hence can be adapted with regard to its energy absorption capacity, possibly by several orders of magnitude.

[0055] The lattice-shaped component structure here can be easily adapted and manufactured, e.g. additively, due to the geometry of the elementary cells 100, the thickness of the elementary cells 100 of a partition wall and a (volumetric) filling ratio. The starting point here for example is a reference cell 100R of a lattice-shaped component structure 10, which is shown by way of example in FIG. 8. This reference cell 100R has a cross-sectional area A, defined by edge lengths a, b. The adjacent webs have a web width or wall thickness d1 and d2. In particular the area A, the edge lengths a, b and the web widths d1, d2 can be varied in connection with a design in order to specify a lattice adapted to changed requirements and, on this basis, specify a lattice-shaped component structure 10. In particular, a simple modeling process can be used to specify a component 1 for different applications with a varied lattice structure 10 without having to vary the dimensions of the component 1 itself. i.e. in particular its required volume of installation space. Via an adaptation of the lattice-shaped component structure 10, however, for example the energy absorption capacity per volume or per kg weight of the component 1 can be varied. In particular, the lattice-based or reference cell-based design of the component 1 can take account of different design, installation space, weight, safety and performance requirements without having to significantly change the basic design of the component 1 and its outer contour. Merely one elementary cell 100 on which the respective lattice structure is to be based is varied on the basis of the predefined reference cell 100R.

[0056] In particular, the component can form different portions and hence zones that differ from each other with regard to the lattice taken as a basis for the lattice structure. Thus, at least two portions of the component each are formed in a lattice-shaped component structure, but here with differently designed lattices whose elementary cells 100 hence differ from each other in terms of their variation proceeding from the reference cell 100R.

[0057] The lattice-shaped component structures 10 of the illustrated design variants of FIGS. 1A to 8 in principle can be manufactured by means of additive manufacturing. The proposed solution, however, is not fixed on such a manufacturing method.

LIST OF REFERENCE NUMERALS

[0058] 1 component [0059] 10 component structure [0060] 10.0 component opening [0061] 10.1, 10.2 component arm [0062] 10.3 component base [0063] 100 elementary cell [0064] 100R reference cell [0065] 10a, 10b structural part [0066] 11 cutout (first type) [0067] 12 cutout (second type) [0068] 12.1, 12.2 second contact area [0069] 120 partition wall/first contact area [0070] 120.1, 120.2 shear surface [0071] 120a, 120b breaking point [0072] 121 (shear) fracture [0073] 13 cutout (third type) [0074] 14 partition wall [0075] 14a, 14b breaking point [0076] 15 support portion [0077] A area [0078] a, b edge length [0079] B bending/buckling point [0080] d1, d2 web width/wall thickness [0081] F force [0082] G projectile [0083] L bearing [0084] l.sub.1, l.sub.2 length [0085] S shear force [0086] V failure crack [0087] α flank angle