Deformation Structure, in Particular for Pedestrian Protection for a Motor Vehicle

Abstract

A deformation structure, which is an energy absorption structure, has a series of deformation elements arranged one behind the other in a deformation direction, i.e. the direction in which a load acts. Each two adjacent deformation elements are coupled together by a coupling mechanism, such that in a first load case, in particular a first collision load case, two adjacent deformation elements enter into a latching engagement with one another or are positioned in a latching engagement, such that a relative displacement of the adjacent deformation elements with respect to one another in the deformation direction is prevented, or at least made more difficult, and a deforming of the deformation structure occurs at a high level of force, and in a second load case, in particular a second collision load case, two adjacent deformation elements do not enter into the latching engagement or leave a latching engagement, such that a relative displacement of the adjacent deformation elements in the deformation direction is enabled, or at least made easier, and a deforming of the deformation structure occurs at a low level of force.

Claims

1. A deformation structure for a motor vehicle arranged between a bumper covering and a bumper transverse support, comprising: a row of deformation elements arranged one behind the other in a deformation direction, wherein in each case, two mutually adjoining deformation elements are mutually coupled via a coupling mechanism such that: (i) in a first load event, two adjoining deformation elements will enter into a mutual latching engagement or are in a latching engagement, so that a relative displacement of the adjoining deformation elements with respect to one another in the deformation direction is prevented or at least made more difficult and a deforming of the deformation structure takes place at a high force level, and (ii) in a second load event, two adjoining deformation elements do not enter into the latching engagement or leave the latching engagement, so that a relative displacement of the adjoining deformation elements in the deformation direction is made possible or at least facilitated, and a deforming of the deformation structure takes place at a low force level.

2. The deformation structure according to claim 1, wherein each deformation element, as a component of the coupling mechanism, has an elastically deformable element, which engages with the adjoining deformation element and, in the first load event, is in the latching engagement with the adjoining deformation element, or enters into the latching engagement with the adjoining deformation element and, in the second load event, does not enter into the latching engagement with the adjoining deformation element or leaves the latching engagement of the adjoining deformation element.

3. The deformation structure according to claim 2, wherein the coupling mechanism is designed such that the elastically deformable element is elastically prestressed or is elastically prestressable by a relative displacement of two adjoining deformation elements, and the coupling mechanism is designed such that, while utilizing a mass inertia of the prestressed elastically deformable element, at a first displacement speed, the elastically deformable element of the one deformation element enters in the latching engagement with an indentation or a projection of the other deformation element, and the elastically deformable element, at a second higher displacement speed, does not enter into the latching engagement with the indentation or the projection.

4. The deformation structure according to claim 3, wherein the first displacement speed is lower than the second displacement speed.

5. The deformation structure according to claim 2, wherein the elastically deformable element of a deformation element is designed to interact with an adjoining deformation element such that, with a displacement of the adjoining deformation elements with respect to one another, the elastically deformable element is elastically deformable and prestressable by way of a slanted contact surface of the adjoining deformation element.

6. The deformation structure according to claim 3, wherein the elastically deformable element of a deformation element is designed to interact with an adjoining deformation element such that, with a displacement of the adjoining deformation elements with respect to one another, the elastically deformable element is elastically deformable and prestressable by way of a slanted contact surface of the adjoining deformation element.

7. The deformation structure according to claim 2, wherein the elastically deformable element is a leaf-shaped leg, whose forward end has a detent or a detent indentation for a latching engagement with the adjoining deformation element.

8. The deformation structure according to claim 6, wherein the elastically deformable element is a leaf-shaped leg, whose forward end has a detent or a detent indentation for a latching engagement with the adjoining deformation element.

9. The deformation structure according to claim 7, wherein each deformation element in constructed to be U-shaped with a basic element and two opposite legs, which each form the elastic element, and ends of the legs are coupled with the basic element of a further deformation element.

10. The deformation structure according to claim 1, wherein each deformation element is constructed in one piece, and the deformation elements are made of a plastic material.

11. The deformation structure according to claim 1, wherein a plurality of rows of deformation elements are arranged side-by-side.

12. The deformation structure according to claim 11, wherein deformation elements arranged directly side-by-side are mutually connected via a web which is constructed so as to fail in a brittle and/or plastic manner in an event of a collision load.

13. The deformation structure according to claim 1, wherein the deformation elements are adapted to absorb, in the latching engagement state, energy by plastic deforming and/or brittle failure of the deformation element along a specified deformation distance.

14. The deformation structure according to claim 13, wherein an energy absorption capacity of the deformation elements, which are in a latching engagement or remain in the latching engagement, is greater than an energy absorption capacity of the deformation elements which do not enter in the latching engagement or leave the latching engagement.

15. The deformation structure according to claim 1, wherein the deformation elements have identical constructions.

16. The deformation structure according to claim 1, wherein the deformation structure is configured as a pedestrian protection structure between the bumper covering and the bumper transverse support.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0053] FIG. 1 is a schematic lateral view of a section of a deformation structure for pedestrian protection for a motor vehicle according to an embodiment of the present invention.

[0054] FIG. 2 is a schematic perspective view of the deformation structure according to the embodiment of the present invention.

[0055] FIGS. 3A to 3G are schematic lateral views of the deformation structure according to the embodiment of the present invention in a collision load event at a higher speed.

[0056] FIGS. 4A to 4G are schematic lateral views of the deformation structure according to the embodiment of the present invention in a collision load event at a lower speed.

DETAILED DESCRIPTION OF THE DRAWINGS

[0057] In the following, embodiments of the present invention will be described with reference to FIGS. 1, 2 3A to 3G and 4A to 4G.

[0058] FIG. 1 illustrates a basic section of a deformation structure 1 according to an embodiment of the present invention. According to the embodiment, the deformation structure 1 is mounted on a front end of a motor vehicle, particularly in front of a bumper transverse support, which is not shown, instead of a known pedestrian protection foam. In particular, the deformation structure 1 is arranged in a space between a vehicle skin, i.e. a bumper covering, and the bumper transverse support.

[0059] As illustrated in FIG. 1, the deformation structure 1 has a row of deformation elements 3 arranged one behind the other. The deformation elements 3 are mutually coupled by way of a coupling mechanism 5. Each deformation element 3 has an essentially U-shaped construction consisting of a basic element on which two leaf-shaped legs 51 are arranged which can be elastically deformed toward the outside. The two opposite legs 51 extend essentially in the longitudinal direction of the vehicle, in which case the following explanation will only relate to one leg 51, and in which case the other leg 51 is constructed symmetrically thereto. A forward end of the leg 51 borders on the basic element of the adjoining deformation element 3 and has a detent 55, which, as required, engages with the adjoining basic element. The basic element has a slanted contact surface 57, behind which a detent indentation 53 is constructed. The contact surface 57 has a slope in the longitudinal direction of the vehicle.

[0060] FIG. 2 is a perspective view of the deformation structure 1. The deformation structure 1 has several rows of deformation elements 3 arranged side-by-side, i.e. in the y-direction of the motor vehicle, and above one another, i.e. in the z-direction of the motor vehicle. Deformation elements arranged side-by-side and above one another are mutually connected by way of thin webs 7. As a result of the webs 7, the rows of deformation elements 3 are mutually connected and the deformation structure 1 forms an integral modular unit. The number of rows of deformation elements 3 and the number of the deformation elements 3 in each row can be selected according to the requirements.

[0061] The deformation structure 1 is preferably produced of a plastic material, whereby the deformation structure can be produced in a cost-effective manner and can be constructed to be of a sufficiently light weight. In particular, the deformation structure 1 can be produced in one piece by way of a rapid manufacturing process. As an alternative, the deformation elements 3 may be produced separately and be combined with one another and connected via a suitable automated mounting process.

[0062] In the following, a function of the deformation structure 1 will be described with reference to FIG. 1 and FIG. 2 as well as FIGS. 3A to 3G and FIGS. 4A to 4G.

[0063] In the case in which a load is applied in the longitudinal direction of the row of deformation elements 3 as a result of a collision—in FIG. 1 from the right side—the forward end of the leg 51 is pressed via the detent 55 against the slanted contact surface 57. As soon as a frictional force between the detent 55 and the contact surface 57 has been overcome, the detent 55 will slide along the contact surface 57, whereby the leg 51 is elastically deformed toward the outside, while the deformation element 3 is displaced by the collision load in the direction of the adjoining deformation element 3. As a result, the leg 51 is successively prestressed until it reaches the end of the contact surface.

[0064] The further course of the displacement of the adjoining deformation elements 3 with respect to one another depends on the respective collision load event. In FIGS. 3A to 3G, the pedestrian protection load event is indicated to be equal to or above a predefined collision speed of 20 km/h. In FIGS. 4A to 4G, the low speed load event is indicated to be below the predefined collision speed of 20 km/h. The specified collision speed is only mentioned here as an example and may also have a different value.

[0065] With reference to FIGS. 3A to 3G, a function of the deformation structure 1 is first described in the event of a collision of the motor vehicle at a collision speed of approximately 20 km/h and more.

[0066] FIG. 3A illustrates the condition before the start of the deforming of the deformation structure 1. FIG. 3B finally shows an initial elastic deforming of the legs 51 of the first deformation element 3-1 and of the second deformation element 3-2. FIG. 3C illustrates how the detents 55 of the legs 51 of the second deformation element 3-2 start to slide along the slanted contact surfaces 57 of the third deformation element 3-3 and are thereby elastically prestressed. FIG. 3D shows how the detents 55 of the legs 51 of the second deformation element 3-2, as a result of a fast displacement speed and its mass inertia, slide over and beyond the indentations 53 of the third deformation element 3-3 without penetrating into the indentations 53 or engaging with the latter. FIG. 3E illustrates how the second deformation element 3-2 is therefore pushed further in the direction of the third deformation element 3-3, wherein the legs 51, as required, are correspondingly further elastically deformed, wherein, however, this elastic deforming takes place at a comparatively low force level. FIG. 3F finally shows how the second deformation element 3-2 was pushed completely against the third deformation element 3-3, and the two basic elements essentially adjoin one another, wherein the collision load acts in an intensified manner upon the third deformation element 3-3, whose detents 55 of the legs 51 finally slide along the contact surfaces 57 of the fourth deformation element 3-4, and the legs 51 of the third deformation element 3-3 are thereby elastically prestressed. FIG. 3G then shows how also the detents 55 of the legs 51 of the third deformation element 3-3 do not engage in the indentations 53 of the fourth deformation element 3-4, and the third deformation element 3-3 at a low force level is displaced further in the direction of the fourth deformation element 3-4. Depending on the course of the collision load, all deformation elements 3 can therefore successively be pushed into one another for the benefit of a pedestrian protection at a lower force level.

[0067] Starting at the collision speed of approximately 20 km/h, it is important that the front end of the motor vehicle front, and particularly the bumper covering in connection with the deformation structure 1 reacts sufficiently softly at a low deformation force level for the protection of a pedestrian. If the collision opponent is a pedestrian, at a speed of approximately 20 km/h and more, a relatively low force therefore acts upon the pedestrian.

[0068] According to the invention, this is implemented by the described coupling mechanism 5 which, on the basis of a mass inertia of the legs 51, functions in an interaction with their elastic prestressing in the course of the collision.

[0069] With reference to FIGS. 4A to 4G, a function of the deformation structure 1 during a collision of the motor vehicle at a collision speed of less than approximately 20 km/h will be described in the following.

[0070] FIG. 4A illustrates the condition before the start of the deforming of the deformation structure 1. FIG. 4B finally shows an initial elastic deforming of the legs 51 of the first deformation element 3-1 and a sliding of the detents 55 on the contact surfaces 57 of the second deformation element 3-2.

[0071] FIG. 4C shows how the detents 55 of the first deformation element 3-1 have reached a maximal prestressing and have arrived at the end of the contact surfaces 57. In FIG. 4D, it is illustrated how the detents 55 of the first deformation element 3-1, as a result of the slow displacement speed and its elastic prestressing, engage in the indentations 53. As a result, a further displacement of the deformation element 3-1 with respect to the deformation element 3-2 is blocked in a form-locking manner. FIG. 4E illustrates how the detents 55 of the second deformation element 3-2 slide along the contact surfaces 57 of the third deformation element 3-3, and the legs 51 of the second deformation element 3-2 are thereby elastically deformed. FIG. 4F shows how a prestressing of the legs 51 of the second deformation element 3-2 reaches a maximum, and the detents 55 have arrived at the end of the contact surfaces 57, and the detents 55 of the leg 51 of the third deformation element 3-3 are already sliding along the contact surfaces 57 of the fourth deformation element 3-4. FIG. 4G illustrates how also the detents 55 of the legs 51 of the second deformation element 3-2 engage in the indentations 53 of the third deformation element 3-3, whereby therefore a further displacement of the second deformation element 3-2 with respect to the third deformation element 3-3 is blocked in a form-locking manner, and the detents 55 of the legs 51 of the third deformation element 3-3 have already arrived at the end of the contact surfaces 57 of the fourth deformation element 3-4 and have reached a maximal prestressing. Depending on the course of the collision load, all deformation elements 3 can therefore form-lockingly engage with one another, so that, on the whole, as a result of the slow collision speed of the motor vehicle and the thereby caused slow displacement speed of the deformation elements 3 relative to one another, the deformation structure 1 has a more rigid effect than in the case of the faster collision speed at which a form-locking engagement of the deformation elements 3 does not take place.

[0072] Therefore, in the case of the slow collision speed, depending on the collision load level, the deformation structure 1 transmits the collision load directly to a structure of the motor vehicle situated behind it, or the individual deformation elements 3 of the deformation structure 1 fail in a brittle manner by breaking and/or failing by plasticly deforming at a higher load level than at the faster collision speed.

[0073] In particular, the deformation structure 1 may be designed such that, at collision speeds of, for example, less than 4 km/h, it can transmit a collision load to the crash structure without any failing of the deformation elements 3. This is advantageous when, in the case of so-called trivial damage when parking a car, or the like, there is to be no damage at the motor vehicle requiring repair, and it influences, for example, an insurance-related classification of the motor vehicle.

[0074] At a higher collision speed which, however, is not yet relevant in terms of pedestrian protection, for example, a speed of between 4 km/h and 20 km/h, the deformation structure 1 may be plastically deformed at a specified load level and/or fail in a brittle manner, so that the deformation structure 1 contributes to the reduction of collision energy, without any damage, for example, to structural elements situated, for example, behind the bumper transverse support, such as a radiator. In this case, only the comparatively cost-efficient deformation structure 1 and, as required, the bumper covering, has to be replaced.

[0075] On the whole, by use of the deformation structure 1 according to the invention, a conflict of objectives can be solved, which, on the one hand, at very low collision speeds, which are not relevant in terms of pedestrian protection, permits a sufficiently high rigidity of the structure or a sufficiently large deforming force level of the deformation structure 1 and, at a slightly higher collision speed, which is relevant in terms of pedestrian protection, ensures sufficient pedestrian protection by means of a low deforming force level.

[0076] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.