Pedestrian protection device for a motor vehicle

Abstract

A pedestrian protection device for a motor vehicle, for example for a motor vehicle front end or a motor vehicle rear end, has a bumper crossmember with a deformation element arranged on the outer side thereof, i.e. the side directed towards the front. In particular, the deformation element is arranged between a bumper skin and the bumper crossmember. The deformation element has a first element and a second element which are displaceable relative to one another in the event of a collision. Furthermore, the pedestrian protection device has a locking mechanism which, in dependence on a displacement speed, and thus on a collision speed, of the motor vehicle, and while exploiting a mass inertia of a locking element which is arranged or mounted on the first element or the second element, is adjustable between a locked state in which a displacement of the first element relative to the second element is at least partially prevented by, in particular, positive engagement, and an unlocked state in which a displacement of the first element is allowed.

Claims

1. A pedestrian protection device for a motor vehicle, comprising: a bumper transverse support; a deformation element, which is arranged on an exterior side of the bumper transverse support, the deformation element having (i) a first element and a second element, which, in the event of a collision, are displaceable relative to one another in the direction of the bumper transverse support, and (ii) a mechanical latching mechanism having a latching element and a spring device, wherein: the mechanical latching mechanism, as a function of a displacement speed while utilizing a mass inertia of the latching element, is adjustable between a latched condition, in which a displacement of the first element relative to the second element is at least partially prevented, and, an unlatched condition, in which a displacement of the first element is permitted, the latching element and the spring device are constructed for interacting such that, via displacement of the first element and the second element relative to one another, the latching element is prestressed by the spring device before the latching element reaches the latched condition.

2. The pedestrian protection device according to claim 1, wherein the latching mechanism is latched below a collision speed threshold value and is unlatched when the collision speed threshold value is reached.

3. The pedestrian protection device according to claim 1, wherein in the case of a displacement of the first element and the second element relative to one another, the latching element engages in an indentation of the second element or first element such that a further displacement of the first element and of the second element relative to one another is prevented.

4. The pedestrian protection device according to claim 3, wherein the spring device is essentially relaxed in an idle state, and the latching mechanism has a contact surface by way of which the latching element is movable against the spring force of the spring device and is thereby prestressed, before the latching element reaches the indentation.

5. The pedestrian protection device according to claim 3, wherein the latching element, the spring device and the indentation are constructed to be interacting such that, in the case of a slow displacement of the first element and the second element relative to one another, the latching element engages in the indentation and, in the case of a fast displacement of the first element and the second element relative to one another, the latching element does not engage in the indentation.

6. The pedestrian protection device according to claim 1, wherein the spring device additionally has a damping device which appropriately dampens a movement of the latching element.

7. A pedestrian protection device for a motor vehicle, comprising: a bumper transverse support; a deformation element, which is arranged on the transverse support and whose deformation region is constructed on an exterior side of the transverse support, wherein the deformation element has: (i) a first element and a second element, which, in the event of a collision, are displaceable relative to one another in the direction of the transverse support, and (ii) a mechanical latching mechanism which has a movable latching element and a spring device, the movable latching element being pre-stressable or being prestressed via the spring device, which latching element is arranged on the first element or the second element and is form-lockingly engageable with an indentation or a step at the other of the first element or the second element, and wherein the latching element and the spring device are constructed to be interacting such that, with a displacement of the first element and the second element relative to one another, the latching element is prestressable via the spring device before the latching element reaches the form-locking engagement with the indentation or the step.

8. The pedestrian protection device according to claim 7, wherein the latching mechanism has a contact surface which is arranged and constructed such that, during a relative movement of the first element and the second element relative to one another, the latching element is movable along the contact surface in contact with the contact surface against the spring force of the spring device and thereby is prestressable before the latching element reaches the form-locking engagement with the indentation or the step.

9. The pedestrian protection device according to claim 8, wherein the spring device, the latching element and the contact surface interact such that: (i) at a high displacement speed, which is greater than or equal to a collision speed threshold value, when the latching element engages with the contact surface, a movement of the latching element along the contact surface is made possible and the latching element upon leaving the contact surface as a result of a mass inertia of the latching element jumps over the indentation or step, and therefore does not form-lockingly engage, and a further displacement of the first element and of the second element relative to one another is made possible, and (ii) at a low displacement speed, which is lower than the defined collision speed threshold value, during the engagement of the latching element with the contact surface, a movement of the latching element along the contact surface is made possible, and the latching element engages with the indentation or the step in a form-locking manner after leaving the contact surface at the low displacement speed.

10. The pedestrian protection device according to claim 9, wherein the contact surface is constructed in a slanted fashion with respect to a displacement direction of the first element and the second element relative to one another.

11. The pedestrian protection device according to claim 1, wherein a deformation region of the deformation element is constructed between a vehicle skin or a bumper covering and the transverse support.

12. The pedestrian protection device according to claim 7, wherein a deformation region of the deformation element is constructed between a vehicle skin or a bumper covering and the transverse support.

13. The pedestrian protection device according to claim 1, wherein the second element is fixed to the transverse support or is an integral component of the transverse support.

14. The pedestrian protection device according to claim 7, wherein the first element is fixed to the transverse support or is an integral component of the transverse support.

15. The pedestrian protection device according to claim 13, wherein the first element is displaceable into an opening of the transverse support.

16. The pedestrian protection device according to claim 1, wherein the deformation element is adapted to absorb, in a latched condition of the locking mechanism, collision energy by plastic deformation and/or brittle failure of the deformation element over a predefined deformation distance in a range of 60 mm to 110 mm.

17. The pedestrian protection device according to claim 16, wherein an energy absorption of the deformation element in the case of the unlatched condition of the latching mechanism is lower than an energy absorption of the deformation element in the case of the latched condition of the latching mechanism.

18. The pedestrian protection device according to claim 1, wherein the deformation element has a length of from 50 to 150 mm, and the first element and the second element are moveable relative to one another in an unlatched condition over a distance of from 60 to 110 mm.

19. The pedestrian protection device according to claim 1, wherein the first element is a cylindrical element, which is displaceable in a corresponding guide of the second element, and the latching element is mounted on the first element or the second element.

20. The pedestrian protection device according to claim 1, wherein the first element is an elastically deformable wall, which forms the spring device, having an end which forms the latching element.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a pedestrian protection device according to a first embodiment of the present invention.

(2) FIG. 2 is a schematic view of the pedestrian protection device according to the first embodiment of the present invention with a prestressed spring device.

(3) FIG. 3 is a schematic view of the pedestrian protection device according to the first embodiment of the present invention in a latched condition.

(4) FIG. 4 is a schematic view of the pedestrian protection device according to the first embodiment of the present invention in an unlatched condition.

(5) FIG. 5 is a schematic perspective view of a pedestrian protection device according to a second embodiment of the present invention.

(6) FIG. 6 is a schematic lateral view of the pedestrian protection device according to the second embodiment of the present invention.

(7) FIG. 7 is a schematic lateral view of the pedestrian protection device according to the second embodiment of the present invention in a condition in which a spring device is prestressed.

(8) FIG. 8 is a schematic lateral view of the pedestrian protection device according to the second embodiment of the present invention in a latched condition.

(9) FIG. 9 is a schematic lateral view of the pedestrian protection device according to the second embodiment of the present invention in an unlatched condition.

DETAILED DESCRIPTION OF THE DRAWINGS

(10) In the following, embodiments of the present invention will be described with reference to FIGS. 1 to 9.

(11) FIGS. 1 to 4 show a pedestrian protection device for a motor vehicle according to a first embodiment of the present invention.

(12) The pedestrian protection device 1 is mounted on a front end of the motor vehicle, particularly a motor vehicle front, having a transverse bumper support 23. In particular, the pedestrian protection device is arranged in a space between a vehicle skin, i.e. a bumper covering 21, and the bumper transverse support 23. As illustrated in FIG. 1, the pedestrian protection device has a deformation element 1 with a first element 3 and a second element 5. The first element 3 and the second element 5 basically have a mutually displaceable or shiftable construction. In particular, the first element 3 can be displaced into the second element 5. The second element 5 is fixed to the bumper transverse support 23 and is rigidly connected with the latter. In addition, the deformation element 1 has a latching mechanism, which can restrict a displacement of the first element 3 with respect to the second element 5. The latching mechanism has a latching element 7 which, by way of a spring 9, can be prestressed and displaced in the transverse direction. In other words, the latching element 7 is arranged in/on the first element 3 so that it can be displaced transversely to the longitudinal direction of the vehicle. The latching mechanism further has a contact surface 13, which is constructed on an interior side of the second element 5, as well as a recess (a type of indentation) 11, which is also constructed in the second element 5, i.e. on its circumference.

(13) The function of the deformation element 1 and particularly of the latching mechanism, will be described in the following with reference to FIGS. 2 to 4. FIG. 2 illustrates a condition in which the motor vehicle is subjected to a collision, and a collision load therefore acts by way of the bumper covering 21 upon the first element 3, whereby the first element 3 is displaced in the direction of the second element 5 and thereby of the bumper transverse support 23. In this case, the latching element 7 comes in contact with the contact surface 13, which is constructed on an interior side of the second element 5. The contact surface 13 is provided with a slope in the longitudinal direction of the vehicle, i.e. in the displacement direction of the first element 3, so that by an interaction between the latching element 7 and the contact surface 13, the latching element 7 is moved in the transverse direction in the course of the displacement and is thereby pressed against the spring device 9, so that this spring device 9 is prestressed. The spring device 9 may additionally have a damping device 20 (illustrated only schematically in FIG. 1 via dashed lines). FIG. 2 illustrates the condition in which a maximal prestressing of the spring 9 has been reached.

(14) FIG. 3 shows a further course of the collision at a relatively slow displacement speed of the first element 3 and, therefore, a relatively low collision speed. After a maximal prestressing of the spring 9 and of the latching element 7, respectively, and a departing from of the contact surface 13, the latching element 7 is pressed in the transverse direction toward the exterior wall of the second element 5. In this case, the latching element 7 engages with a recess 11 in the wall of the second element 5. In this condition, the latching element 7 is in a form-locking engagement with the first element 3 as well as with the second element 5, so that a further displacement of the first element 3 relative to the second element 5 is blocked by the latching element 7. As soon as the condition illustrated in FIG. 3 has been reached, the deformation element 1 will act as a rigid element. In this condition, the deformation element 1 can transmit collision loads from the collision opponent directly to the bumper transverse support 23 and the crash structure of the motor vehicle situated behind the latter. When a specific collision load is exceeded, the deformation element 1 will fail by plastic deformation or brittle failure and will thereby absorb collision energy over a predefined failure distance of maximally the length of the deformation element 1 in the latched condition.

(15) The deformation element 1 is particularly designed such that, at collision speeds of, for example, less than 4 km/h, it can transmit to the crash structure a collision load without deforming.

(16) At a greater collision speed, which is, however, not yet relevant to a pedestrian protection, as, for example, a speed of between 4 km/h and 20 km/h, the deformation element 1 will be deformed at a defined load level, so that the deformation element 1 contributes to the reduction of collision energy, without any damage to, for example, components, such as a radiator, present behind the bumper transverse support 23.

(17) FIG. 4 illustrates a condition, in which no form-locking engagement of the latching element 7 and thereby of the first element 3 with the second element 5 has taken place, and therefore the first element 3 was displaced farther in the direction of the bumper transverse support 23 relative to the second element 5. The condition illustrated in FIG. 4 is reached at a higher displacement speed and, therefore, a higher collision speed. The deformation element 1 may, for example, be constructed such that, starting from a collision speed of approximately 20 km/h, no engagement takes place between the first element 3 and the second element 5, and the deformation element therefore, as a whole, clearly reacts in a softer manner over a longer deforming distance than in the case of the latched condition or engaged condition illustrated in FIG. 3.

(18) As a result of the mass inertia of the latching element 7, the latching element 7 needs a certain time until it has been moved sufficiently far in the transverse direction. At the fast displacement speed of the first element 3, this has the result that the latching element 7 cannot engage in the recess 11 of the second element 5, so that the first element 3 can be displaced farther in the direction of the bumper transverse support 23 and the latching element 7 comes in contact with an interior side of the second element 5 and can be displaced along the interior side. No form-locking engagement will take place between the latching element and the second element 5. The first element may be displaceable into an opening 30 (only shown schematically in dashed lines in FIG. 4) of the transverse support 23.

(19) Starting at the collision speed of, for example, 20 km/h, it is important that the front end of the motor vehicle front section, and particularly the bumper covering in connection with the deformation element 1, react sufficiently softly at a low deforming force level.

(20) According to the invention, this is implemented by the described latching mechanism, which functions on the basis of a mass inertia of the latching element 7 while interacting with the spring force of the spring 9.

(21) Thus, the conflicting objectives can be solved which, on the one hand, at very low collision speeds, requires a sufficiently high rigidity of the deformation element 1 or a sufficiently high deforming force level of the deformation element 1 and, at a slightly higher collision speed, ensures a sufficient pedestrian protection as a result of a low deforming force level.

(22) With reference to FIGS. 5 to 9, the following is a description of a pedestrian protection device according to a second embodiment of the present invention. The pedestrian protection device of the second embodiment is functionally constructed analogous to the pedestrian protection device of the first embodiment but differs from the first embodiment in structural details, in which case, particularly such details with be explained in the following.

(23) FIG. 5 is a perspective view of the pedestrian protection device of the second embodiment having a deformation element 201, which is mounted on a forward side of a bumper transverse support 23 of a front end of a motor vehicle front section. The deformation element 201 is therefore arranged in a space between a bumper covering (not shown) and the bumper transverse support 23. The deformation element 201 has a first element 203 and a second element 205 which, in a latchable manner, can be displaced relative to one another. In particular, in the event of a frontal collision load, the second element 205 can be displaced in the direction of the bumper transverse support 23 and thereby in the direction of the first element 203. The first element 203 is arranged on the bumper transverse support 23.

(24) As illustrated in FIG. 6, the first element 203 has two opposite walls 209, which extend essentially in the longitudinal direction of the vehicle, in which case, the following explanation refers only to the top wall 209, the bottom wall having a construction that is symmetrical thereto. A forward end 207 of the wall 209 is appropriately engaged with the second element 205. The forward end 207 of the wall acts as a latching element according to the present invention and has a hook-shaped curvature. The wall 209 itself further forms a spring device according to the invention, which can be elastically prestressed in a transverse direction. The second element 205 further has a recess 211 in which the latching element 207 can engage. Furthermore, the second element 205 has a contact surface 213 with a slope in the longitudinal direction of the vehicle, by way of which the forward end of the wall 207 as a latching element can be prestressed by way of the wall 209 as the spring device.

(25) FIG. 7 illustrates a condition in which the latching element 207, as a result of the contact with the contact surface 213, was maximally prestressed by way of the wall and spring device 209. The condition shown in FIG. 7 is reached at the start of a frontal collision, during which the second element 205 is displaced in the direction of the first element 203 relative to the first element 203.

(26) FIG. 8 shows a condition in which the forward end of the wall 207, as latching element of the latching mechanism of the deformation element 201, at a relatively low speed of the second element 205, for example, less than 20 km/h, has arrived in a form-locking engagement with the recess 211 and thereby prevents a further displacement of the second element 205 relative to the first element 203.

(27) In this case, an effect of the deformation element 201 is analogous to the deformation element 1 of the first embodiment. At a very low collision speed, the deformation element 201 acts in a sufficiently rigid manner and can thereby transmit collision loads directly to the crash structure situated behind the latter. At a slightly higher collision speed of, for example, 4 km/h to 20 km/h, the deformation element 201 is deformed by plastic and/or brittle failure at a defined force level, so that the deformation element 201 can contribute to a collision energy reduction.

(28) In FIG. 9, a condition is illustrated in which the deformation element 201 is not in the engaged condition in the course of the collision. This condition is reached, starting at a defined displacement speed or collision speed of the second element 205 relative to the first element 203, at which a mass inertia of the latching element 207 has the result that it does not arrive in a form-locking engagement with the recess 211 of the second element 205. As a result, the second element 205 can be displaced at a lower load in the direction of the bumper transverse support 23, in which case, the walls of the first element 203 without an engagement with the second element 205 can be pressed away at a relatively low force level.

(29) As a result, the deformation element 201 of the second embodiment, analogous to the deformation element 1 of the first embodiment, at a relatively high collision speed of, for example, more than 20 km/h, is softer for the benefit of a pedestrian protection.

(30) 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.