DE102010020080A1 - Bumper arrangement for motor car to protect pedestrian during e.g. front collision, has plate provided at guide profile and coupled with crash box, where guide profile is moved relative to crash box - Google Patents

Abstract

The arrangement (1) has a cross beam (2) coupled with a crash box (4) through a guide profile (3). The guide profile is moved relative to the crash box. A plate (7) is provided at the guide profile and coupled with the crash box. The guide profile is coupled with the crash box in form-fit and force-fit manner. The plate is oriented toward a longitudinal axis of the crash box. The guide profile is coupled with the crash box through a locking element (9) i.e. blind rivet, that is arranged in an oblong hole (8) of the plate.

Description

The present invention relates to a bumper assembly according to the preamble of claim 1.

The purpose of bumpers is primarily to absorb impact forces in an impact on an obstacle and to protect the body against structural damage in a low-speed impact. Furthermore, the bumper arrangement serves the protection of pedestrians in a front or rear collision with the motor vehicle.

Buffer assemblies of known type consist mainly in the horizontal plane perpendicular to a respective direction of travel (forward or reverse) arranged rigid cross member. The cross member is preferably connected to two parts under inclusion of designated as crash box components with side member structures of the motor vehicle, or rigidly connected thereto. The crash boxes take the impact energy z. B. in a low-speed frontal crash, as is typical for a rear-end collision, by plastic deformation.

Legal regulations and self-commitments of the automobile industry with regard to pedestrian protection stipulate that the bumpers additionally reduce the load on the lower extremities, for B: to minimize on the legs, if it comes to a collision, for example, between a pedestrian and the vehicle front. Among other things, impact tests with a leg impactor are carried out, whereby certain limit values must be adhered to.

It is known, in particular for pedestrian protection, to arrange or install an energy absorber directly on the front side of the cross member.

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. As a result, a compliance behavior to two levels of force can be realized. The cavity profile consists of two U-shaped nested shell bodies, which are joined together by means of bolts and slot connections. The aim of the arrangement is to first decelerate and decelerate an impact at various levels of force, before permanent plastic deformations of the arrangement occur. The hollow part can penetrate in the event of an impact under compression of the plastic to 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 the case of a pedestrian impact, the lock is switched so that the cross member can be moved backwards with a small force, so that the impact region softens in the leg area. 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.

One of the main disadvantages of the known bumper arrangements is that they largely lead to a significant increase in the overhang in the area of the bumper, for example in the area of the front end of the vehicle. The additional components, mainly molded plastic foam, require additional mounting space in front of the cross member, which must be housed under the outer skin or the plastic cover.

A disadvantage of active systems is that they are usually much heavier than bumper assemblies without active systems. By way of example, systems may be mentioned here which use hydraulic or pneumatic impact absorbers. In addition, such systems significantly increase the cost of an entire bumper assembly over non-actuator or active damping designs. Another disadvantage of actively driven systems can be seen in the additional effort to the relevant components for permanent warranty of functionality z. B. to protect against weather or pollution.

The invention is based on the prior art based on the object to provide a bumper assembly with improved impact absorption available, which is particularly inexpensive to produce, is weight-optimized and has high reliability.

According to the invention the object is achieved with a bumper assembly having the features of patent claim 1.

Advantageous developments of the invention are part of the dependent claims.

The bumper assembly according to the invention for a motor vehicle, which has a cross member and a crash box, wherein the cross member coupled via a guide profile with the crash box and the guide profile is relatively movably connected to the crash box, characterized in that on the guide profile a tab for coupling with the Crashbox is provided.

The coupling of crash box and guide profile according to the invention is preferably formed in a kind of sliding seat. In this case, the guide profile sits in a standby state on the crash box in such a way that it experiences a relative displacement in the event of a vehicle crash via the sliding seat in the direction of the crash box. This relative displacement is preferably carried out by a sliding movement in which the guide profile slides over or in the crash box.

In the context of the invention preferably two crash boxes are installed in the bumper assembly. For coupling Crashbox and guide profile, the guide profile additionally has at least one tab. Preferably, in the context of the invention, two or more tabs are formed. The tab is particularly preferably formed integrally with the guide profile. The tab can also be formed in several pieces with the guide profile. In this case, it is conceivable within the scope of the invention, for example, that the tab is coupled to the guide profile. This coupling can be done, for example, non-positively, positively and / or cohesively.

The components of the bumper assembly are preferably made of metallic materials, such. As steel materials or even made of light metal materials. In the context of the invention, however, it is also conceivable that the components are made of composite materials such as GRP or CFRP. It is also particularly advantageous that hybrid components can be coupled to the bumper arrangement according to the invention. For example, a CFRP crash box can be coupled with a light metal cross member arrangement in turn with a light metal guide profile. For example, however, a composite material guide profile with a metal tab would also be conceivable within the scope of the invention.

Preferably, the guide profile with the crash box is positively and / or non-positively coupled. This ensures that the sliding movement can be transferred as a relative movement between the guide profile and crash box both from a standby state to an activation state, as well as during the slip occurring in the activation state, to absorb crash energy. Tilting of the guide profile to Crashbox is avoided as far as possible. Furthermore, the guide profile and crash box are formed substantially with mutually corresponding shapes. For example, both are designed as a polygonal profile or as a c-shaped profile.

Preferably, the tab is oriented in the direction of the longitudinal axis of the crash box. In the example of a mounting on a front motor vehicle component assembly thus shows the tab in the direction of the vehicle or the crash box. Due to the orientation in the direction of the longitudinal axis of the crash box Here is again given a particularly advantageous arrangement possibility in connection with the positive and / or non-positive coupling. Moving in the direction of the longitudinal axis of the crash box in the event of an accident is also promoted by an orientation of the tab oriented toward the crash box longitudinal axis.

The bumper assembly according to the invention also allows by their construction a special consideration to meet the requirements of pedestrian protection. By retracting the cross member over the path of the guide profile until the crash box comes to a stop with the cross member, only a small impact force is required. This is the case, for example, if a motor vehicle encounters a pedestrian. Furthermore, in the context of the invention, a spring means and / or a damper means may be arranged inside the guide profile. This may be, for example, an elastomeric element, in particular in the form of an elastomeric spring. On the one hand, the spring ensures that the system returns to the stop determined by a locking element or, in the case of an elastomer, also takes over a damping action.

In a further particularly preferred embodiment, the tab rests against the crash box at least in places. This regional concern increases the efficiency of the positive and / or positive coupling of guide profile with Crashbox. Here, it is conceivable, for example, that the crash box is made of a hollow profile without recesses or with recesses. The tab would thus rest at least partially on the crash box.

In the case of a crash box with recesses, it is thus possible within the scope of the invention to influence the section of the crash box with the recess by the fold-throw behavior of the tab for a positive crash energy absorption capacity. In the case of the crash box without a recess, the entire area of the flap in relation to the flap is preferably used to generate an activation state. It therefore requires an increased impact force to activate the sliding seat of the bumper assembly. In the case of application in a motor vehicle, for example, a slight impact as a result of a parking bump will not be decisive for the fact that the system is already activated. In the event of impact with a stronger object, this force threshold is exceeded, resulting in a relative shift of the guide profile to the crash box.

In a further preferred embodiment, the tab has an opening, preferably a slot, wherein a central axis of the opening is oriented in the direction of the crash box. The tab offers with the opening a weight reduction, without appreciable influences on the drape behavior or the possibilities of positive and / or non-positive coupling. Furthermore, an opening, for example in the form of a mounting opening or even an elongated hole, offers the possibility of further positive and / or non-positive coupling possibilities with the crash box. Likewise, the opening, for example in the form of a mounting opening or else also weight-reducing openings, makes it possible to configure the tabs in such a way that they have a specific bending behavior or else also a drape behavior.

Particularly preferably, the guide profile is coupled to the crash box via a locking element arranged in the opening. The locking element offers the possibility of positively locking the system together in a particularly preferred manner. The locking element is particularly preferably a blind rivet. This offers, in particular, the possibility of coupling the entire system cost-effectively and quickly producible with high production reliability with different materials. In the context of the invention, however, the locking element can also be a locking element, which is designed, for example, in the form of a bolt and is coupled to the Crahsbox by means of a material-locking and / or positive-locking connection. For example, this cohesive connection in the form of a weld, in particular a spot welding, done and / or the form-fitting coupling, for example in the form of a screw arrangement. It is also possible to additionally cohesively couple a screw arrangement, for example by gluing, soldering or welding.

Another resulting advantage of the locking element is that the system is prevented from jamming when being slammed into each other. It is also possible with the locking element, for example, to guide the tab parallel spaced to the crash box. Furthermore, with the locking element by variations of the cross section of a slot the possibility to generate different retraction stages of the system. These retraction stages may include, for example, a breakdown of crash energy in several steps. Furthermore, the release force can be selected selectively in any height by the locking element. Likewise, targeted guidance of the tab during the relative movement between the tab and the crash box with the locking element is possible. For example, guiding the tabs away from the crash box would be conceivable, so that the crash box is not hindered by the tabs in their drape behavior.

In a further embodiment, a guiding of the tabs parallel to the crash box is conceivable, so that the drape behavior of the crash box is complemented by the drape behavior of the tabs.

In a further preferred embodiment variant, a displacement path of the guide profile in relation to the crash box is determined at least in sections by the length of the opening. This results in the possibility that the guide profile performs a relative movement to the crash box, which is limited by the displacement, which is given by the slot in connection with the locking element. This may, for example, be an advantage in the form of different crash energy absorption levels of the entire bumper system.

With the possibility of kinetic energy dissipation during a vehicle crash, it is thus conceivable that moves first by the relative movement of the cross member on the sliding seat on the crash box. At the end of the displacement of the sliding seat, the slot meets the locking element, so initially further retraction is prevented. Subsequently, the degree of energy absorption capacity increases due to the fact that the crash box guide profile and cross member are positively engaged. For example, now the Führungsprofilfalten until the cross member completely meets the crash box. Depending on the requirement profile of the energy absorption capacity, there is a particularly advantageous embodiment possibility here.

In a further preferred embodiment of the present invention, the tab and the guide profile have different hardness from each other. It is particularly advantageous if, for example, the tabs in relation to the rest of the guide profile have a high hardness, so that they could break off during or after activation of the system. Another particularly advantageous embodiment is that the tabs in relation to the guide profile have a lower hardness, so they do not hinder the drape behavior of the crash box.

Preferably, the locking element is arranged in a standby state of the bumper assembly so that a relative movement of the guide profile against the direction of the crash box is not possible. In the case of the sliding seat between the guide profile and crash box, the locking element is inserted into the opening of the tab in a production process after attaching the guide profile on the crash box or even plugging into the crash box. After insertion, it is no longer possible to separate the components Crashbox and guide profile from each other, as a positive end stop limit is given against the mounting direction by the locking element. This guarantees that the system basically remains in its standby state and is not accidentally tilted or otherwise deformed, for example, during a workshop visit.

Particularly preferably, the locking element is designed as a blind rivet. The blind rivet here offers the particular advantage that it is particularly simple and inexpensive in a slot and a mounting hole can be introduced. The blind rivet also has the advantage that it can be riveted with different strengths, so that, for example, a frictional grinding movement takes place during the relative movement between crash box and guide profile. However, the blind rivets can also be designed so that it only makes an end stop limit on the guide profile, but does not hinder the movement. For example, a blind rivet is conceivable, which is used as a spacer between the guide profile and tab.

In the context of the invention, it is also conceivable that a transition region extending between the tab and the guide profile and the guide profile and the tab itself have different stiffnesses. These stiffnesses can be adjusted for example by different material strengths. It is also conceivable to use different materials, for example a steel material and also an aluminum material. Likewise, the rigidity or strength behavior and, as a result, a bending behavior of the flange can be achieved by means of different wall thicknesses or even cross-sectional geometries.

Further advantages, features, properties and aspects of the present invention will become apparent from the following description, a preferred embodiment with reference to the schematic figures. This is for easy understanding of the invention. Show it:

1 a bumper assembly according to the invention in a perspective view;

2 a bumper assembly according to the invention in a side view;

3 a bumper assembly according to the invention in a sectional view and

4 a detailed view of the section of 3 ,

In the figures, the same reference numerals are used for the same or similar parts, if corresponding or comparable advantages are achieved, even if a repeated description is omitted for reasons of simplification.

1 shows a bumper assembly according to the invention 1 , comprising a cross member shown in sections 2 , a leadership profile 3 , a crashbox 4 and a coupling plate 5 , In the embodiment shown here is the cross member 2 with the guide profile 3 positively coupled. The coupling can take place cohesively and / or positively and / or non-positively. The leadership profile 3 again has a receiving area 6 on top of it the crashbox 4 includes. In addition, there is a tab 7 on the guide profile 3 educated. The tab 7 again has a slot 8th on. The leadership profile 3 goes in a transition area Ü in the tab 7 above.

In the slot 8th is a locking element 9 arranged. The bumper arrangement 1 is in a ready state B. The locking element 9 prevents a movement opposite to the direction RC of the crash box 4 , At the same time it allows a relative movement R in the direction of RC crash box 4 , Through the slot 8th in engagement with the locking element 9 learns the entire bumper assembly 1 a guide so that angling with respect to the image plane up, down, left or right is not possible.

2 shows the bumper assembly 1 in a side view. It can be seen here that the guide profile 3 on the cross member 2 is fixed. The leadership profile 3 overlaps in this embodiment in the receiving area 6 the crashbox 4 , Furthermore, a displacement path 6a through the tab 7 in engagement with the locking element 9 specified. Also is in 2 to realize that the leadership profile 3 the crashbox 4 at a cross beam end 10 the crashbox 4 in the recording area 6 covered. The crashbox 4 itself may have further beads or shapes and reinforcing plates to influence the drape behavior. However, these are not shown here for reasons of simplification.

3 shows a sectional view in the horizontal center plane of the crash box assembly. It can be seen that the tabs 7 on both sides of the crashbox 4 are arranged. The tabs 7 experienced by the locking element 9 a positive fixation.

Out 4 is evident that the tab 7 with her slot 8th through the locking element 9 is guided. The bumper arrangement 1 is in a standby state B. In the event of a vehicle crash, the tab experiences 7 and the associated, not shown here, guide profile a relative movement R in the direction RC of the crash box. The tab 7 is doing over the slot 8th and the locking element 9 guided. Furthermore, it is shown that the thickness DV of the area for receiving the tab 7 on the locking element 9 is greater than the thickness DL of the tab 7 ,

LIST OF REFERENCE NUMBERS

1

bumper assembly

2

crossbeam

3

guide profile

4

crash box

5

coupling plate

6

reception area

7

flap

8th

Long hole

9

locking element

10

End to 4 ,

B

standby

RC

Direction crash box

R

relative movement

DV

Thickness of 9

DL

Thickness of 7

Ü

Transition area

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 4413641 C1 [0006]
• DE 3232940 C2 [0007]
• DE 19806541 A1 [0008]
• DE 10329754 B3 [0009]
• DE 19847385 C1 [0010]
• DE 102004059545 A1 [0011]

Claims (13)

Bumper assembly ( 1 ) for a motor vehicle having a cross member ( 2 ) and a crashbox ( 4 ), wherein the cross member ( 2 ) via a leadership profile ( 3 ) with the crash box ( 4 ) and the management profile ( 3 ) relatively movable at the crash box ( 4 ), characterized in that on the guide profile ( 3 ) a tab ( 7 ) for coupling with the crash box ( 4 ) is provided. Bumper arrangement according to claim 1, characterized in that the guide profile ( 3 ) with the crash box ( 4 ) is coupled positively and / or non-positively. Bumper arrangement according to claim 1 or 2, characterized in that the tab ( 7 ) in the direction (RC) of the longitudinal axis of the crash box ( 4 ) is oriented. Bumper arrangement according to one of claims 1 to 3, characterized in that the tab ( 7 ) at the crash box ( 4 ) at least partially applied. Bumper arrangement according to one of claims 1 to 4, characterized in that the tab ( 7 ) has an opening, preferably a slot ( 8th ), wherein a central axis of the opening in the direction (RC) of the crash box ( 4 ) is oriented. Bumper arrangement according to claim 5, characterized in that the guide profile ( 3 ) with the crash box ( 4 ) via a locking element arranged in the opening ( 9 ) is coupled and the locking element ( 9 ) positively and / or cohesively with the crash box ( 4 ) connected is. Bumper arrangement according to claim 5 or 6, characterized in that a displacement of the guide profile ( 3 ) in relation to the crash box ( 4 ) is determined at least in sections by the length of the opening. Bumper arrangement according to one of claims 1 to 7, characterized in that the tab ( 7 ) and the leadership profile ( 3 ) have different hardnesses from each other. Bumper arrangement according to one of claims 1 to 8, characterized in that the locking element ( 9 ) in a standby state (B) of the bumper assembly (FIG. 1 ) is arranged so that a relative movement (R) of the guide profile ( 3 ) against the crash box ( 4 ) not possible. Bumper arrangement according to one of claims 6 to 9, characterized in that the locking element ( 9 ) is designed as a blind rivet. Bumper arrangement according to one of claims 1 to 10, characterized in that between the guide profile ( 3 ) and the crashbox ( 4 ) At least one spring means, preferably an elastomeric spring, and / or a damper means is arranged. Bumper arrangement according to one of claims 1 to 11, characterized in that between the tab ( 7 ) and the leadership profile ( 3 ) a transition region is formed, wherein the transition region and the tab ( 7 ) have different cross-sectional geometries. Bumper arrangement according to claim 12, characterized in that the tab ( 7 ) and / or the leadership profile ( 3 ) and / or the transition region Ü have a mutually different wall thickness.

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