Crash structure for a motor vehicle, method for producing a crash structure of this type, and motor vehicle having a crash structure of this type

Abstract

The invention relates to a crash structure for a motor vehicle, comprising a carrier body, from the carrier surface of which at least one deformation unit formed integrally with the carrier body protrudes, which deformation unit is formed by at least two deformation elements arranged one over the other and connected to each other and by an impact surface, wherein: a longitudinal section of each deformation element has two longitudinal section surfaces lying opposite each other and following respective non-straight curves; the impact surface is spaced apart from the carrier surface by the deformation elements.

Claims

1. Crash structure for a motor vehicle, comprising a carrier body, from a carrier surface of which at least one deformation unit formed integrally with the carrier body protrudes, which deformation unit is formed by at least two deformation elements arranged one above the other and connected to each other and by an impact surface, wherein a longitudinal section of each deformation element has two longitudinal section surfaces lying opposite each other and following respective non-straight curves, wherein an impact surface is spaced apart from the carrier surface by the deformation elements, and wherein each of the respective non-straight curves is a branch of a hyperbola.

2. Crash structure according to claim 1, wherein a cross-section of the respective deformation elements has a cross-sectional surface following an oval.

3. Crash structure according to claim 1, wherein the two deformation elements in a respective proximal region arranged close to the carrier surface enclose a larger surface in a respective inner peripheral direction than in a respective distal region, arranged remote from the carrier surface.

4. Crash structure according to claim 1, wherein a connection element (26) arranged between the two deformation elements, via which the two deformation elements are connected to one another.

5. Crash structure according to claim 4, wherein an outer contour of the connection element is designed at least substantially as a truncated cone, the outer surface of which forms a predetermined angle with a parallel to the carrier surface.

6. Crash structure according to claim 1, wherein the impact surface and the carrier surface are arranged at an angle to each other.

7. Crash structure according to claim 1, wherein the impact surface and the carrier surface are arranged parallel to each other.

8. Crash structure according to claim 1, wherein at least one further deformation unit, wherein the first and the further deformation unit are arranged one above the other and/or next to one another along the carrier surface.

9. Crash structure according to claim 1, wherein the carrier body has at least one lateral tab, via which the crash structure can be incorporated in the motor vehicle.

10. Motor vehicle comprising a crash structure designed according to claim 1, by means of which an impact energy can be converted, at least in large part, into a deformation energy by deforming at least one of the two deformation elements.

11. Motor vehicle according to claim 10, wherein at least one bumper which is at least partially formed by the crash structure.

12. Method for manufacturing a crash structure designed according to claim 1, comprising the steps of: providing the carrier body having a flat portion; heating at least the flat portion of the carrier body by means of a heating device of a forming tool; and generating a negative pressure between the flat portion of the carrier body and a negative mould of the forming tool of the at least one deformation unit by means of a vacuum device of the forming tool, whereby a material of the flat portion is applied on an inner contour of the negative mould and as a result the at least one deformation unit is formed on the carrier body.

Description

(1) The drawing shows, in:

(2) FIG. 1 a perspective view of a crash structure:

(3) FIG. 2 a perspective view of the crash structure cut along a sectional plane shown in FIG. 1;

(4) FIG. 3 a longitudinal sectional view of a deformation unit along the sectional plane shown in FIG. 1;

(5) FIG. 4 a partial view of the crash structure, cut along a sectional plane shown in FIG. 3, with a view of the interior of the deformation unit;

(6) FIG. 5 a perspective view of the crash structure according to a further embodiment, cut along the sectional plane shown in FIG. 1;

(7) FIG. 6 a schematic illustration of a motor vehicle comprising the crash structure;

(8) FIG. 7 a schematic sequence of method for manufacturing the crash structure;

(9) FIG. 8 a perspective illustration of a flap of a motor vehicle; and

(10) FIG. 9 a sectional view along a longitudinal section plane perpendicularly intersecting the flap.

(11) In the figures, the same or similarly-functioning elements are provided with the same reference signs.

(12) FIG. 1 shows a perspective view of a crash structure 1 for a motor vehicle 2 (first shown in FIG. 6). A plurality of deformation units 4 extends from an at least substantially cuboid designed carrier body 3. In particular, the respective or individual deformation units 4 protrude from a carrier surface 5 of the carrier body 3. In the present example, the crash structure 1 has 38 deformation units 4, which are arranged in two parallel rows of 19 deformation units 4 each.

(13) The respective deformation unit 4 has at least two, in the present case three, deformation elements 6 arranged one above the other and connected to one another, by which a respective impact surface 7 is spaced apart from the carrier surface 5.

(14) When making a comparison between deformation units 4a that are arranged at least substantially centrally on the carrier body 3 and the deformation units 4b arranged outside the centre of the carrier body 3, it can be seen that the individual deformation elements 6 of the central deformation units 4 can be arranged coaxially one above the other. In the case of the deformation units 4b further away, it can be provided that the respective deformation elements 6 are not arranged coaxially to one another.

(15) In order to enable a particularly advantageous incorporation of the crash structure 1 in the motor vehicle 2, the carrier body can have a radius 8 such that the carrier body can be viewed as part of an outer surface of a circular cylinder determined by the radius 8, which can be straight or perpendicular.

(16) FIG. 2 shows the crash structure in a perspective and sectional view, wherein a section plane A-A is drawn in FIG. 1. It can be seen that the deformation units 4, in particular the deformation units 4a, have the deformation elements 6 which are each arranged coaxially to one another along a longitudinal centre axis 9 of the deformation unit 4, 4a. Further, it can dearly be seen from FIG. 2 that the deformation units 4, 4a, 4b are each formed in one piece with the carrier body 3, whereby the crash structure 1 is formed. Here, the deformation units 4 are each formed as a concave material extension of the carrier body 3 when viewed from an inner surface 10 of the carrier body 3 opposite the carrier surface 5, wherein the deformation units 4 are each formed as a convex material extension of the carrier body 3 when viewed from the carrier surface 5.

(17) The crash structure 1 can have at least one lateral tab 11, in the present example two lateral tabs 11. Looking again at FIG. 1, it can be seen that the respective lateral tab 11 can comprise a fastening device 12 which can have a plurality of through-openings 13, which completely penetrate the respective lateral tab 11. By way of example, the through-openings 13 can each be a slot through which a fastening element, for example a screw, a rivet etc., can be arranged, so that the crash structure 1 can be particularly easily fastened in a known manner to a carrier structure and/or another component of the motor vehicle 2.

(18) For the invention, it is essential that the respective deformation element 6 has two mutually opposite longitudinal section surfaces 15 and 16 in a longitudinal section 14, each of which follows a non-straight curve 17, 18 (first shown in FIG. 3).

(19) FIG. 3 shows one of the deformation units 4 in a longitudinal sectional view along the sectional plane A-A (see FIG. 1). It can be seen particularly clearly that an outer peripheral surface 19 of the respective deformation element 6 in the sectional view of FIG. 3 follows a respective one of the two curves 17, 18 along the longitudinal centre axis 9. In this case, the curves 17, 18 are each formed differently from a straight line. In particular, a mathematical function describing the respective curves 17, 18 can be given according to a formula
z=x.sup.2−y.sup.2  F1
or
x=y.Math.z  F2.

(20) It goes without saying that the formulas F1, F2 can be parameterised, in that the variables are mathematically linked to a parameter or a plurality of parameters in one or more positions. Thus, the respective curves 17, 18 can be designed, for example, as a hyperbola branch.

(21) The curve 17 and the curve 18 can be respective branches of a common hyperbola, wherein the two branches are shifted and/or rotated separately from one another in such a way that when an inner peripheral surface 20 of the corresponding deformation element 6 viewed, it is concave along the inner peripheral direction thereof. Further, the two curves 17, 18 can each belong to their own hyperbola, wherein for better understanding a hyperbola 21 belonging to the curve 17 and a hyperbola 22 belonging to the curve 18 are partially shown in FIG. 3.

(22) FIG. 3 also shows that a deformation element 6a directly adjoining the carrier surface 5 is connected in this connection region 23 to the carrier body 3. Further, the deformation element 6b adjoining the deformation element 6a has a connection region 24, via which the deformation element 6b is connected to the deformation element 6a. Analogously, the deformation element 6c adjoining the deformation element 6b has a connection region 25, via which the deformation element 6c is connected to the deformation element 6b.

(23) In the present example, a connection element 26 is arranged in each case between the deformation element 6a and the deformation element 6b, as well as between the deformation element 6b and the deformation element 6c, which connection element is arranged in the respective connection region 24, 25 and/or at least partially forms the respective connection region 24, 25. In other words, the deformation element 6a and the deformation element 6b, as well as the deformation element 6b and the deformation element 6c, are connected to one another via a respective connection element 26. In particular, it is provided that the deformation elements 6a, 6b, 6c, the connection elements 26 and the impact surface 7 are formed together with the carrier body 3, for example by deep drawing, so that the respective deformation unit 4 for the crash structure 1 is formed.

(24) In the longitudinal section of the deformation unit 4 shown in FIG. 3, and consequently of which the respective connection element 26 can be identified, it can be seen that an outer contour 27 of the respective connection element 26 is designed at least substantially as a truncated cone. Here, an outer surface 28 of the truncated cone and a parallel 29 to the carrier surface 5 or to the carrier body 5 form a predetermined angle 30 with one another. The angle 30 is particularly preferably 3 degrees, although the depiction of the deformation unit 4 in FIG. 3 is not the true angle for purposes of better illustration. In the installed state of the crash structure 1, the longitudinal centre axis 9 of the deformation unit 4 and a vehicle longitudinal direction 31 (see FIG. 6) can coincide with one another, so that the parallel 29 can be a vertical.

(25) FIG. 4 shows a partial view of the crash structure 1 cut along a sectional plane B-B shown in FIG. 3 looking into the interior of the deformation unit 4, wherein the illustrated deformation unit 4 extends in the plane of the drawing. The cross-section shown there of the deformation unit 4 follows an oval 32, which in the present example is designed as a circle. It thus emerges, in particular when looking at FIG. 4 with FIG. 3, that the inner peripheral surface 20 of the respective deformation element 6 is doubly curved. This applies in an analogous manner to the outer peripheral surface 19 of the respective deformation element 6. In the present example, the respective deformation elements 6 and the connection elements 26 each have a circular cross-sectional surface 33, which is shown as a representative of the deformation elements 6 and of the connection elements 26 on the deformation element 6a.

(26) Referring again to FIG. 3 it is clearly visible that the respective deformation element 6 has a proximal region 34 and a distal region 35. The positional information (proximal/distal) of the two regions 34, 35 are each relative to the carrier body 3 or to the carrier surface 5. This means that a respective proximal region 34 is arranged closer to the carrier body 3 or to the carrier surface 5 than the corresponding distal region 35 of the same deformation element 6. Looking at FIG. 3 together with FIG. 4, it can be seen particularly clearly that the respective deformation elements 6 in the respective proximal region 34 are designed larger than in the respective distal region 35. More precisely, the respective deformation element 6 encloses a larger surface in its proximal region 34 arranged close to the carrier surface 3 than in the respective distal region 35, arranged remote from the carrier surface 5. In the present example, the respective surface enclosed by the respective deformation element 6 designed as a circular disc. As a result, an outer contour can be given for the respective deformation element 6, which can be referred to as egg-shaped. This means that the respective deformation element tapers along the longitudinal centre axis 9 in the direction away from the carrier surface 5, wherein the enclosed surface or circular disc between the proximal region 34 and the distal region 35 of the deformation element 6 in question can be larger than the regions 34, 35. In other words, the respective deformation element 6 can first widen exactly once along the longitudinal centre axis 9 in the direction away from the carrier surface 5, in order to taper further away from the carrier surface 5 to the circular disc enclosed in the distal region 35.

(27) In the present case, one of the connection elements 26 or the impact surface 7 is arranged directly in the respective distal region 35 of the respective deformation element 6. With the deformation elements 6a, 6b, the corresponding connection region 24, 25, which can be formed by the respective connection element 26, is arranged in their respective distal region 35. It can also be clearly seen that for a pair of deformation elements 6, for example the deformation elements 6a, 6b, the deformation element 6 further away from the carrier surface 5, for example the deformation element 6b, has a proximal region 34 which is smaller than a distal region 35 of the deformation element 6 arranged closer to the carrier surface 5, for example the deformation element 6a.

(28) When considering a pair or a group of deformation elements 6, for example the deformation elements 6a, 6b, 6c, the impact surface 7 is arranged in the distal region 35 of the deformation element 6 spaced apart furthest from the carrier surface 5, in particular formed in one piece with the corresponding deformation element 6, 6c. The impact surface 7 can be arranged substantially parallel to the carrier body 3 or to the carrier surface 5. It is however also conceivable, that a respective impact surface 7 of the corresponding deformation unit 4 can be arranged at an angle to the carrier body 3 or to the carrier surface 5. This is illustrated in FIG. 5, which shows a perspective view of the crash structure 1 cut along the sectional plane A-A shown in FIG. 1. Such a geometrical design of the crash structure 1 takes into account a concept of a particularly efficient pedestrian protection in a particular way, since in the event of an impact of the motor vehicle 2 with another party involved in the accident the crash structure 1 is adapted to a contact surface of the other party involved in the accident, in particular to spatial dimensions of the other party involved in the accident, whereby in a particularly advantageous manner, the other party involved in the accident is caught by the crash structure 1, whereby the severity of injury in the accident for the other party involved in the accident is particularly low.

(29) In comparison to the previously described embodiments of the crash structure 1, the crash structure 1 depicted in FIG. 5 shows only one deformation element 6 for a respective deformation unit 4, but the specific positional design of the respective impact surface 7 can be easily transferred to deformation units 4 that have more than one deformation element 6.

(30) It can also be seen in FIG. 5 that the respective impact surface 7 can have a rounding, in particular on the outside thereof facing away from the carrier surface 5, in order to be able to even better apply the impact surface 7 on the outer contour of the other party involved in the accident.

(31) FIG. 6 shows a schematic illustration of the motor vehicle 2, which is fitted with a crash structure 1 or plurality of crash structures 1. It is in particular an advantage if regions of the motor vehicle 2, in particular along the outer contour thereof, are equipped with a crash structure 1 or a plurality of crash structures 1, which will be hit with a particularly high probability by the other party involved in the accident, in particular by a head, torso and/or at least one extremity of the other party involved in the accident. Correspondingly, it can be provided that a front bumper 36, a rear bumper 37 and/or side bumper 38 is/are formed at least partially by a respective crash structure 1 or plurality of crash structures 1. In particular in an accident of the motor vehicle 2 with a pedestrian, it can be particularly advantageous if a flap 39, in particular an engine compartment lid, a boot lid etc., is equipped with a crash structure 1 or a plurality of crash structures 1. Should the pedestrian or a cyclist hitting the side of the motor vehicle 2 be lifted on to a roof 40 of the motor vehicle 2 due to the accident and be hit there, the severity of an injury resulting from this can be kept particularly low by means of a roof 40 equipped with a crash structure 1 or a plurality of crash structures 1. In particular, the individual deformation elements 6 or the individual deformation units 4, 4a can be arranged such that the respective impact surface 7 faces the potential other party involved in the accident. Alternatively or in addition, deformation elements 6 or deformation units 4, 4a are provided, which are arranged such that the corresponding impact surface 7 faces away from the potential other party involved in the accident. For example, a respective impact surface 7 can be supported on the support structure of the motor vehicle 2. In particular, the deformation elements 6 of the crash structure 1 can protrude in a common direction from the common carrier body 3.

(32) FIG. 7 shows a schematic illustration of a sequence of a method for manufacturing the crash structure 1. Here, the carrier body 3 is provided in a first method step S1, which in the undeformed state has at least one flat portion 41 or is designed at least substantially or completely flat, in particular cuboid. Here, the carrier body 3 can be provided as sheet goods, as is also illustrated in FIG. 7. It is however also conceivable that the carrier body 3 is provided as rolled goods. Before a further method step, it can be provided that the not yet deformed carrier body 3 is trimmed, for example, with respect to its longitudinal and/or transverse dimensions.

(33) In a further, for example second, method step S2, the at least substantially completely cuboid carrier body 3 or the flat or completely cuboid portion 41 of the carrier body 3 is provided or supplied to a forming tool 42 which comprises a heating device 43. Then, at least the flat portion 41 of the carrier body 3 is heated by means of the heating device 43. In particular, the flat portion 41 of the carrier body 3 is heated by means of the heating device 43 to a deformation temperature, at which the carrier body 3 can be particularly efficiently deformed. It is therefore particularly advantageous if the carrier body 3 is manufactured at least substantially from thermoplastic, which can be deformed at the thermoplastic deformation temperature.

(34) In a further step S3, the heated carrier body 3 is brought into overlap with a negative mould 44 of the forming tool 42. Here, an inner peripheral contour 45 of the negative mould 44 follows at least substantially an outer contour of the at least one deformation unit 4 to be moulded on the carrier body 3. In particular, the negative mould 44 can be designed to form a plurality of deformation units 4 simultaneously. The heated carrier body 3 is particularly advantageously brought into interaction with the negative mould 44, in such a way that an inflow and/or outflow of a gas, in particular air, via a contact surface between the carrier body 3 and the negative mould 44 is at least substantially excluded.

(35) A negative pressure is then generated between the flat portion 41 of the heated carrier body 3 and the negative mould 44 of the forming tool 42 by means of an undepicted vacuum device of the forming tool 42. As a result, portions of the heated and consequently thermoplastically deformable carrier body 3 directly adjacent to the inner peripheral contour 45 are sucked into the negative mould 44. Accordingly, in this method step, the crash structure 1 is manufactured in that a material of the carrier body 3, in particular thermoplastic, rests on the inner peripheral contour 45 of the negative mould 44. Hence the thus deformed carder body 3 has the flat portion 41, which is interrupted by the vacuum-formed deformation units 4. Accordingly, the carrier body 3 and the respective deformation units 4 are formed in one piece. In this way, a particularly simple method for manufacturing the crash structure 1 is provided, wherein the crash structure 1 can be manufactured in a particularly material efficient manner, since machining of the carrier body 3 is completely eliminated.

(36) It can also be part of the manufacturing method that the lateral tabs 11 are connected to the carrier body 3 or, similarly to the respective deformation units 4, are formed in one piece together with the carrier body 3.

(37) Overall the invention discloses how the impact energy between the motor vehicle 2 involved in an accident and the other party involved in the accident is converted in a particularly advantageous manner into a deformation energy by means of the crash structure 1 which is particularly easy to manufacture. Particular attention is paid here to the protection of pedestrians, who are usually involved in accidents with motor vehicles, wherein the motor vehicle has a particularly low speed, in particular less than 50 kilometres per hour.

(38) The crash structure 1 manufactured from a thermoplastic, in particular polypropylene, has a particularly advantageous resistance to a hit with a high flexural strength, since polypropylene has a corresponding crystalline lattice structure.

(39) Due to the at least partially hyperbolically or parabolically formed cross-section of the respective deformation units 4, which are each at least partially defined by the formulas F1 and/or F2, a double curvature results for each individual one of the deformation elements 6 of the respective deformation units 4. As a result, the crash structure 1 can be produced in a particularly mass-efficient manner, wherein this high efficiency is effective during an impact of another party involved in the accident on the crash structure 1.

(40) By means of the manufacturing method provided, the crash structure 1 is particularly simple and/or inexpensive to manufacture, in particular to manufacture cost effectively, using a vacuum thermoforming process.

(41) A further core concept of the present invention is a stepped hyperbolic and parabolic cross-section, which in the present example is designed in three steps. This guarantees that the respective deformation unit 4 of the crash structure 1 is designed to be multiple, in particular triple, collapsible, wherein by way of example, only a first step collapses due to the impact energy, if the impact energy is particularly low. If the impact energy exceeds a certain value, then alternatively or in addition the first step, the second and/or the third step of the corresponding deformation unit 4 can be collapsed by means of the impact energy.

(42) FIG. 8 shows a perspective illustration of a flap 46, for example an engine compartment lid, of the motor vehicle 2. The crash structure 1, which is bonded to an inner side 47 of the engine compartment lid 46 via its lateral tabs 11, can clearly be seen. It can also be seen that the deformation units 4, 4a (only some of which are provided with the corresponding reference sign in FIG. 8 for reasons of clarity) starting from the carrier body 3 extend in the direction towards the interior 47 of the flap 46. In other words, the deformation units 4, 4a are arranged between the carrier body 3 and the inner side 47.

(43) FIG. 9 shows a sectional view along a longitudinal sectional plane intersecting the flap 46 perpendicularly. It can be clearly seen in this sectional view that the individual deformation units 4, 4a are supported on the inner side 47 of the flap 46 via the respective impact surface 7.

LIST OF REFERENCE SIGNS

(44) 1 crash structure 28 outer surface

(45) 2 motor vehicle 29 parallel

(46) 3 carrier body 30 angle

(47) 4 deformation unit 31 vehicle longitudinal direction

(48) 4a deformation unit 32 oval

(49) 4b deformation unit 33 cross-sectional surface

(50) 5 carrier surface 34 proximal region

(51) 6 deformation element 35 distal region

(52) 6a deformation element 36 bumper

(53) 6b deformation element 37 bumper

(54) 6c deformation element 38 bumper

(55) 7 impact surface 39 flap

(56) 8 radius 40 roof

(57) 9 longitudinal centre axis 41 portion

(58) 10 inner surface 42 forming tool

(59) 11 tab 43 heating device

(60) 12 fastening device 44 negative mould

(61) 13 through-openings 45 inner peripheral contour

(62) 14 longitudinal section 46 flap

(63) 15 longitudinal section surface 47 inner side

(64) 16 longitudinal section surface

(65) 17 curve F1 mathematical formula

(66) 18 curve F2 mathematical formula

(67) 19 outer peripheral surface

(68) 20 inner peripheral surface S1 method step

(69) 21 hyperbola S2 method step

(70) 22 hyperbola S3 method step

(71) 23 connection region

(72) 24 connection region

(73) 25 connection region

(74) 26 connection element

(75) 27 outer contour