DE102008027811A1 - Bumper arrangement for e.g. front area of motor vehicle, has cross beam comprising guiding profile that is designed corresponding to crash-box and connected to crash-box over guiding profile in movable manner relative to crash-box - Google Patents

Abstract

The arrangement has a cross beam (2) comprising a guiding profile (7) that is designed corresponding to a crash-box (3) and connected to the crash-box over the guiding profile in a movable manner relative to the crash-box. An energy absorption unit (14) is arranged between the crash-box and the cross beam, and locking units (15) are arranged between the guiding profile and the crash box, where the locking units are designed as screws or bolts. Openings formed as longitudinal holes are arranged in a wall of the crash-box, where the crash-box has a supporting unit (9).

Description

The The invention relates to a bumper assembly for the front or rear area covered by an outer skin a motor vehicle according to the features in the preamble of claim 1, wherein the bumper assembly having a cross member, the inclusion of at least one crash box with side member structures of the motor vehicle is connected.

bumper serve primarily the purpose in case of an impact on an obstacle To absorb shock forces and the body at a low speed impact from structural damage to protect. Furthermore, the bumper assembly is used the protection of pedestrians at a front or Rear-end collision with the motor vehicle.

bumper assemblies known type consist in the main of one in the horizontal plane perpendicular to a respective direction of travel (forward or Reverse drive) arranged rigid cross member. The cross member is preferably in two places under inclusion of Crashbox designated components with side member structures connected to the motor vehicle, or rigidly connected to this. The crash boxes take the impact energy z. B. in a frontal impact at low speed, as is typical for a rear-end collision inland, by plastic deformation. Legal provisions and self-commitments of the automotive industry a pedestrian protection specify that the bumper In addition, the stresses on the lower extremities z. B: to minimize on the legs, in case of a collision, for example between a pedestrian and the vehicle front comes. These include impact tests with a leg impactor carried out, whereby certain limit values are to be kept.

Known is, especially for pedestrian protection an energy absorber directly to the front of the cross member to arrange or to install.

The DE 44 13 641 C1 for example, provides a trained as an energy absorber cross member. On the front side of the cross member are arranged on this supporting impact damper made of an energy absorbing material, which preferably consists of plastic foam or a honeycomb structure made of plastic.

In addition to plastic foams or honeycomb or pore-shaped energy absorber elements and resilient structures are arranged or mounted in front of the cross member. The DE 32 32 940 C2 z. B. discloses a bumper for a motor vehicle, consisting of a vehicle-fixed parts supporting rigid carrier with bent in the vehicle longitudinal direction lateral end portions, which is preceded by a wave-shaped, over the length of the bumper including its bent end portions extending leaf spring. The leaf spring and the carrier are integrally formed of plastic.

In the scope of DE 198 06 541 A1 is a bumper assembly with a cross member known, which is designed as a hollow part, in which plastic foam layers of different density are provided.

hereby should realize a compliance behavior on two levels of force can be. The cavity profile consists of two U-shaped nested shell bodies, which by means of bolts and Slot connections are joined together. The order pursues the goal of impacting at different levels of force first slow down and slow down before it becomes permanent plastic deformation of the arrangement comes. The hollow part can in case of an impact under compression of the plastic after penetrate the rear and so absorb the impact energy (partially).

From the DE 103 29 754 B3 , which goes back to the applicant, a bumper assembly is known, which has a cross member connected to the longitudinal members of the motor vehicle frame. The cross member is preceded by a running in the longitudinal direction of the force distribution element with a distance x, which is supported by springs on the cross member and is surrounded by a foam body. The cross member is closed at the front by a strike plate, whereby the springs pass through the strike plate.

In addition to the passively designed systems, bumper arrangements are also known which can react to an impact with actively activatable elements. For example, the DE 198 47 385 C1 a bumper assembly having a bumper movably mounted between a rest position and a functional position. For this purpose, springs are provided, one of which is formed from a shape memory material, which retrieves the bumper from the operating position to the rest position.

It is also known to integrate an active lock in the crash box parts, so as to obtain a switchable system which can switch between two operating states. If the lock is switched for a hard impact, the crash box takes over the load and destroys the impact energy by plastic deformation. In case of a pedestrian impact, the locks switched so that the cross member can be moved with a small force to the rear, so that the impact region in the leg area is softer. With such an active system, for example, the DE 10 2004 059 545 A1 , which discloses that for each of the three basic crash types "parking bumps", "pedestrian impact" and "vehicle crash" with the occurring different impact velocities or kinetic energies to be absorbed, selectively different compliances in the area of the vehicle front should be provided.

When a major disadvantage of the known bumper assemblies is to be regarded that this largely to a significant increase in the overhang in the bumper area, so for example in the area of the front end. The additional Components, mainly moldings made of plastic foam, need additional mounting space in front of the cross member, the additionally under the outer skin or the plastic cover must be accommodated.

adversely In active systems, these are usually much heavier as bumper arrangements without active systems are. By way of example, systems can be mentioned here. which use hydraulic or pneumatic impact absorbers. In addition, such systems increase the cost of an entire bumper assembly clearly opposite the construction methods without actuators or actively damping elements. Another disadvantage of actively driven systems is in the additional effort to see the relevant components for permanent guarantee of functionality z. B. against weather or against contamination to protect.

Of the Invention is therefore based on the prior art, the task based, a bumper assembly with improved Shock absorption behavior and simultaneous reduction or elimination of components in front of the cross member for Reduction of an overhang available too put.

According to the invention the task with a bumper assembly with the features of claim 1, wherein the cross member a so executed to Crashbox corresponding guide profile having that cross member over the guide profile movable relative to the crash box attached to this.

Of the Cross member is made of a rigid, at least partially opened, preferably completely open profile, z. B. one U-profile with a U-bar and two extending away from it U-legs executed. It is also conceivable, the cross member as a hollow body from an at least partially closed, preferably completely closed profile z. B. from an extruded profile or from To form interconnected metal shells. The crossbeam may be one or more extending in its longitudinal direction Have hollow chambers. For a closed profile can only openings provided for attachment of the guide profile be. About the crash box is the cross member Side member structures of the motor vehicle tethered.

In preferred embodiment, the crash box is at her to the cross member oriented end designed such that axial forces can be introduced into the crash box. The crashbox can be welded together Sheet metal shells, pipe profiles or also from hydroforming parts be formed, just to give a few examples to the design of the crash box call, and is usually designed as a hollow profile. To initiate axial forces in the crash box is advantageously provided, at least that to the cross member oriented end of the crash box, for example, with a support element to provide. The support element can be designed, for example, as an end wall be, but also conceivable, the support element as to perform circumferential edge or as a bent edge. Of course, other suitable measures can be taken be taken to initiate an axial force in the crash box to be able to.

The axially movable connection of the cross member to the crash box is achieved in a preferred embodiment so that the guide profile has an inner contour, which on the outer contour of the crash box at least in the region of the end oriented to the cross member is adjusted. More specifically, the leadership profile one adapted to the outside diameter of the crash box Inner diameter on, so that the crash box in the guide profile, preferred essentially free of play is inserted. The leadership profile surrounds the crash box so at least in the area of the cross member oriented end. This is an axial displacement of the cross member over allows the guide profile relative to the crash box. Alternatively, the outer contour of the guide profile be adapted to the inner contour of the crash box to an axial displacement of the cross member over the guide profile relative to the crashbox.

In a preferred embodiment, the cross member is oriented in its open configuration with its exemplary U-web oriented either to the front or to the rear side, so that the respective U-legs are oriented towards a vehicle center. In other words, the U-legs of a front cross member extend to the rear, where are oriented towards the U-legs of the rear cross member forward. By This advantageous arrangement is created by the U-legs formed additional space that can be used as an additional space for movement of the axial displacement. Conveniently, it is therefore provided to arrange the guide profile on a front wall opposite to the rear side of the cross member. In a preferred embodiment, the guide profile with its free end is about something over the free ends of the U-leg over. If the cross member designed as a closed profile (extruded profile), as mentioned above, usefully made breakthroughs in the opposite front wall to the rear wall in order to secure the guide profile sufficiently to the cross member can. Of course, in an open profile, a separate closing wall can be provided as a rear wall with corresponding recesses or openings.

expedient in the context of the invention, when the guide profile sleeve-like with a fixing end and the opposite free End is executed. With the attachment end is the guide profile attached to the back of the cross member, being the free ends, as already described, preferred over free ends of the U-legs or on the rear wall survive the cross member. Thus, the crash box inserted in a preferred embodiment in the guide profile become. In a further preferred embodiment, the crash box with their end oriented to the cross member so in the leadership profile pushed in that a clearance between the to the cross member oriented end and the back of the cross member is formed. In a preferred embodiment is in the open space arranged an energy absorbing element, which z. B. as elastic Compression spring or damper is executed. The energy absorption element stands in the ground state under such a compression bias, that the cross member is also secure during the journey is held. This means that the cross member during the ride can not move uncontrollably and rattling noises or similar causes.

Possible is, the guide profile cohesively, form-fitting or frictionally connected to the cross member, for example, welded joints, glued joints or screw connections are possible to only a few exemplary types of connection to call.

Around To maintain the compressive bias, are in an advantageous embodiment Locking elements between the guide profile and the crash box intended. The locking elements can be designed as sheet metal tabs be that from the leadership profile towards the inside the crash box can be inflected. In a preferred embodiment the locking elements are designed as a bolt or screw, which be plugged through the guide profile and the crash box can, and optionally z. B. via a mother can be secured.

expedient in the context of the invention, if openings for the blocking elements in the walls of the crash box or the guide profile are arranged, which preferably at least in the wall of the crash box are designed as slots. The metal tabs engage in the openings of the crash box. Are the Locking elements designed as screws or bolts are of course both in the management profile and in the Crashbox provided corresponding openings, wherein the openings in the wall of the guide profile may preferably be designed as a round hole. The slots in the wall of the crash box are corresponding the desired axial displacement of the cross member executed relative to the crashbox. At the cross member oriented end of the slot, the blocking element is supported in the ground state, which means that the blocking element in the ground state at a cross member oriented end of the opening in the crash box wall.

In another aspect of the invention is advantageously provided that the openings for the blocking elements so executed are that the slot width may be less than a diameter, for example of the bolt, so that the opening or the thus formed Slot is widened in an impact. This will be cheaper A way of converting the impact energy into deformation energy. The opening can be executed quasi keyhole-like be. It is also conceivable, for example, the bolt with oversize fit insert into the opening to a widening or deformation at to effect a longitudinal displacement.

Possible is a towing hook directly to the side rail structure to arrange. Of course, the blocking elements are included usefully designed so that tensile forces, which z. B. occur when towing, introduced into the vehicle structure can be. It is possible, of course also, a (detachable) screw connection of the towing hook to provide at the crash box. For example, while the towing hook pushed through an opening in the cross member and in a arranged on the front of the crash box or on the end wall Screwed nut or threaded hole.

At the entire length of the front wall of the cross member Optionally, a thin foam element as additional Be arranged protection (eg pedestrian), which as Füllschaum between the cross member and the Outer shell or lining acts and also a first having impact damping function.

at The invention converts the energy absorbing element located in the space between the cross member and the crash box the impact energy in the event of an impact first in an elastic deformation around. The amount of energy that is absorbed corresponds the energy that comes in a collision z. B. with a pedestrian leg or at a slight parking bump arises. Is the initiated Energy z. B. in a collision on a stationary motor vehicle larger, so the energy absorption element on Block, so loaded all over, and the maximum load is fully initiated in the crash box, so there a plastic deformation can take place for energy absorption.

All in all is the space between the cross member and the outer skin kept low with the invention and only by a thin Able filling foam filled, which a rattle and prevent other sounds. An additional overhang, As usual in the art, it will be successful avoided. In the case of a slight impact will only an elastic, reversible deformation of the structures around the Cross member produced.

The The functionality of the crash box remains complete receive. Furthermore, one to the requirements of a vehicle manufacturer Custom Crashbox possible, as there are only a few restrictions for the outer contour of the crash box apply. So should the outer contour z. B. on the length, which an axial displacement or a compression should of course be constant stay in the leadership profile without resistance to be able to deflect.

the Pedestrian protection is successful by the elastic Displacement of the crossbeam taken into account. Across from a fixed cross member are advantageous acceleration peaks avoided, with a homogeneous energy transfer z. B. between the bouncing leg and the front or rear car structure takes place.

The The invention will be described below with reference to the schematic drawings illustrated embodiments explained in more detail. Show it:

1 a bumper assembly in a longitudinal section,

2 the bumper arrangement 1 in a perspective view,

3 to 5 a bumper assembly with different connection possibilities of the guide profile to an open cross member, and

6 a configuration of an opening for receiving a blocking element.

1 shows a bumper assembly 1 for the front area of a motor vehicle clad by an outer skin (not shown). Of course, the erfindungemäße bumper assembly can also be used for the rear of the vehicle. The bumper arrangement 1 should absorb the energy resulting from an impact and both the vehicle structure and z. B. protect pedestrians from damage or injury.

The bumper arrangement 1 has a cross member 2 on, the inclusion of crash boxes 3 is connected to the side member structures of the motor vehicle. In the illustrated embodiment, only one of the possible two or more crash boxes is possible 3 shown.

The crossbeam 2 is an example as an open profile U-shaped with a U-web 4 and two U-thighs 5 executed. The U-thighs 5 are at their free ends 6 toward a center axis X of the bumper assembly 1 bent. The U-thighs 5 are oriented in the illustrated embodiment in the direction of a vehicle tail, not shown. The crossbeam 2 assigns one to the crash box 3 executed guide profile 7 on that the cross member 2 about the leadership profile 7 relative to the crashbox 3 axially movably guided on this. In that sense comes the crashbox 3 a double function too. On the one hand, the crashbox connects 3 the crossbeam 2 with the side member structure. On the other hand, the crash box takes over 3 a guide function in the case of an impact possible axial displacement of the cross member 2 ,

The crashbox 3 is at her to the cross member 2 oriented end 8th by way of example with a support element 9 provided to axial forces in the crash box 3 to be able to initiate. In the illustrated embodiment, the support element 9 designed as an end wall. Conceivable but also embodiments of the support element 9 as a circumferential border or as a bent edge, just to name a few examples. The crashbox 3 is formed by way of example from a hollow tube profile.

The leadership profile 7 is sleeve-like designed as a hollow profile, and with its attachment end 10 on a backside 11 of the subway 4 attached, for example, welded. Further connection possibilities and configurations are in the 3 to 5 shown, which will be discussed in more detail below. To the attachment end 10 oppositely arranged free ends 12 of the leadership profile 7 stand something over the free ends 6 of the crossbeam 2 above. In this respect, the leadership profile 7 advantageous in the space between the two U-legs 5 arranged so that additional movement space for the axial displacement of the cross member 2 can be used.

As in 1 shown by way of example is the crash box 3 with her to the cross member 2 oriented end 8th in the leadership profile 7 inserted. Here is the support element 9 preferably to the back 11 of the underground bridge 4 spaced, leaving a free space 13 is formed.

In the open space 13 is an energy absorbing element 14 taken, which is designed in the illustrated embodiment as an elastomer damper. The energy absorption element 14 fills the free space 13 seen in the longitudinal direction (central axis X) completely off, so that this one on the back 11 of the underground bridge 4 and on the other to the cross member 2 oriented end 8th the crashbox 3 or on the support element 9 the crashbox 3 is applied.

The energy absorption element 14 is in the in 1 illustrated basic state under such a compressive bias that the cross member 2 is also kept secure during the journey.

In order to maintain the pressure bias are blocking elements 15 between the leadership profile 7 and the crashbox 3 intended. In the embodiment shown, the locking elements 15 designed as a bolt, which by the guide profile 7 and the crashbox 3 are plugged. These are in the walls of both the guide profile 7 as well as the crashbox 3 openings 16 respectively. 17 brought in.

Again 2 can be seen more clearly, is the opening 16 in the wall of the guide profile 7 designed as a round hole. The round hole is due to the design of the blocking element 15 customized. The opening 17 in the wall of the crash box 3 In contrast, in the embodiment according to 2 designed as a slot which extends parallel to the central axis X extending. The slot is preferably designed so that a sufficient, axial displacement of the cross member 2 to the crashbox 3 is possible. In the ground state are the blocking elements 15 at a cross member oriented end of the opening 17 at.

6 shows a further embodiment of at least the opening 17 in the wall of the crash box 3 , In the illustrated embodiment, the opening 17 quasi keyhole-like with a diameter of the bolt, for example, adapted head area 18 , which in a longitudinally extending slot area 19 passes over. The head area 18 is to the cross member 2 oriented. The slot area 19 can have a smaller slot width relative to the diameter of the exemplary bolt, so that the slot area 19 in an impact and the resulting longitudinal displacement is widened. In this respect, impact energy can be converted into deformation energy.

Of course, the openings 16 respectively. 17 respectively arranged opposite one another, so that the blocking elements 15 or the exemplary bolts can be arranged accordingly.

3 shows a possible embodiment of the cross member 2 , which on the U-thighs 5 each one in the direction of the central axis X bent inner flange 20 having. The inner flange 20 extends in the illustrated embodiment with its free ends 21 to the management profile 7 , The leadership profile 7 in each case has a connection bottle arranged on both sides of the central axis X. 22 on, which with the inner flange 20 connected is. In this respect, an additional connection of the guide profile 7 to the cross member 2 In addition to the previously described connection of the guide profile 7 with the back 11 of the underground bridge 4 possible. Of course, either one of the compounds described or both can be realized together. As connection type of the guide profile 7 to the cross member 2 is a cohesive, a positive or a non-positive connection possible. It is conceivable, for example, a welding, gluing or screwing. In the embodiment according to 3 is a screw connection 23 selected.

Usually a cross member 2 several crash boxes 3 assigned, so of course, several leadership profiles 7 are provided. Possible is the leadership profiles 7 To connect via a connecting element, for example in the embodiment as a connecting plate, which is more or less as a closing wall for closing the opened cross member 2 can serve. The connecting plate is of course as previously described with the inner flange 20 connectable.

According to the embodiment 4 are the free ends 21 of the inner flange 20 Seen in cross section something to the leadership profile 7 spaced. Otherwise, the embodiment corresponds to 4 that of the embodiment too 3 , where also in 3 as in 4 illustrated two screw connections 23 possible are. Alternatively or additionally, bonding is possible.

In 5 are the free ends 21 of the inner flange 20 how to 3 described down to the leadership profile 7 guided. By waiving the in 3 illustrated connecting flange 22 is this guide profile 7 with the inner flange 20 example cohesively connected. The cohesive connection is, for example, as a weld, z. B. as fillet weld 24 executed.

The embodiments of the 3 - 5 have in common that the leadership profile 7 almost as a strike plate for the U-shaped cross member 2 serves.

1

bumper assembly

2

crossbeam

3

crash box

4

U-web

5

U-leg

6

free ends of 5

7

guide profile

8th

to 2 oriented end of 3

9

supporting

10

attachment end

11

Back of 4

12

free end of 7

13

free space

14

Energy absorbing element

15

blocking element

16

Opening in 7

17

Opening in 3

18

head area

19

slot area

20

inner flange

21

free end of 20

22

connecting flange

23

screw

24

fillet

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 4413641 C1 [0005]
• - DE 3232940 C2 [0006]
• - DE 19806541 A1 [0007]
• - DE 10329754 B3 [0009]
• - DE 19847385 C1 [0010]
• DE 102004059545 A1 [0011]

Claims (10)

Bumpers arrangement, for the front or rear of a motor vehicle, which a cross member ( 2 ), which incorporates crash boxes ( 3 ) is connectable to side member structures of the motor vehicle, characterized in that the cross member ( 2 ) so to the crash box ( 3 ) correspondingly executed guide profile ( 7 ), that the cross member ( 2 ) via the leadership profile ( 7 ) relative to the crash box ( 3 ) is movably connected to this. Bumper arrangement according to claim 1, characterized in that the cross member ( 2 ) is formed from an at least partially open and / or from an at least partially closed profile. Bumper arrangement according to claim 1 or 2, characterized in that the crash box ( 3 ) at her to the cross member ( 2 ) oriented end ( 8th ) a supporting element ( 9 ) having. Bumper arrangement according to one of the preceding claims, characterized in that the crash box ( 3 ) with her to the cross member ( 2 ) oriented end ( 8th ) in the leadership profile ( 7 ), wherein the guide profile ( 7 ) to the crossbeam ( 2 ) oriented end ( 8th ) of the crash box ( 3 ) surrounds. Bumper arrangement according to one of the preceding claims, characterized in that the guide profile ( 7 ) on a back side ( 11 ) of the underground bridge ( 4 ) of the cross member ( 2 ) is arranged. Bumper arrangement according to one of the preceding claims, characterized in that the crash box ( 3 ) with her to the cross member ( 2 ) oriented end ( 8th ) so in the leadership profile ( 7 ), that a free space ( 13 ) between the cross member ( 2 ) or its rear side ( 11 ) and to the cross member ( 2 ) oriented end ( 8th ) of the crash box ( 3 ) is formed. Bumper arrangement according to one of the preceding claims, characterized by an energy absorption element ( 14 ), which is located between the crash box ( 3 ) or to the cross member ( 2 ) oriented end ( 8th ) of the crash box ( 3 ) and the cross member ( 2 ) or its rear side ( 11 ) is arranged. Bumper arrangement according to one of the preceding claims, characterized by blocking elements ( 15 ), which between the leadership profile ( 7 ) and the crashbox ( 3 ), wherein at least openings ( 17 ) in the wall of the crash box ( 3 ) are arranged. Bumper arrangement according to claim 8, characterized in that the locking elements ( 15 ) are designed as sheet metal tabs or as bolts or screws, wherein the openings ( 17 ) are formed as a slot. Bumper arrangement according to claim 8 or 9, characterized in that the opening ( 17 ) has a slot width which is smaller than a diameter of the blocking element ( 15 ) or the bolt.