DE102014224444A1 - Impact-damping component arrangement for a motor vehicle - Google Patents

Abstract

The invention relates to an impact-damping component arrangement for a motor vehicle. The invention has for its object to provide an impact-damping component assembly for a motor vehicle available, which has a small footprint and yet high demands on pedestrian protection justice. An impact-damping component arrangement (10) according to the invention in the region of a front carriage (12) of a motor vehicle (14) comprises a transverse support (22) and a first energy absorption part (24) arranged in front of the transverse support (22) viewed in the vehicle longitudinal direction, wherein the first energy absorption part (24) an integrated or immediately adjacent arranged sensing element (28) for controlling the movement of a motor vehicle part in dependence on the state of the first energy absorption part (24) and viewed in the vehicle longitudinal direction in front of the first energy absorption part (24), a second energy absorption part (32) is arranged and wherein the second energy absorption part (32) is designed and arranged such that it causes an at least partial compression of the first energy absorption part (24) in the longitudinal direction of the motor vehicle (14) from the front to the second energy absorption part (32) acting, sufficiently large forces.

Description

The invention relates to an impact-damping component arrangement for a motor vehicle according to the preamble of claim 1.

Out DE 10 2004 024 468 A1 an impact-damping component arrangement for a vehicle is known, according to which one or more crease walls are to be arranged as absorption elements between an outer skin and a bumper cross member. The kink walls are to be used instead of known from the prior art foam parts and compared to these have the advantage that they have no block length and thus a larger deformation path between the outer skin and bumper cross member is available.

Out DE 10 2006 030 504 A1 For example, a bumper for a motor vehicle is known, in which an energy absorption element is arranged between an outer skin designated as a bumper cover and a bumper cross member.

The invention has for its object to provide an impact-damping component assembly for a motor vehicle available, which has a small footprint and yet high demands on pedestrian protection justice.

The object is achieved according to the invention with the features of claim 1. Further practical embodiments and advantages of the invention are described below in conjunction with the subclaims.

An impact-damping component arrangement according to the invention in the region of a front end of a motor vehicle comprises a cross member and a first energy absorption part arranged in front of the cross member viewed in the vehicle longitudinal direction, the first energy absorption part being an integrated or immediately adjacent sensing element for controlling the movement of a motor vehicle part in dependence on the state of the first energy absorption part includes. As an example of a sensing element is at this point in particular referred to a hose whose compression (caused by the first energy absorption part) can be used as a control signal to move an engine hood of a motor vehicle in the vehicle vertical direction upwards. Thus, pedestrian protection can be improved in the event of a pedestrian impact with the hood, since then the hood is enlarged to the engine block underneath and other solid components due to an increased distance, and more deformation path for impacting body parts of the pedestrian is available. In the same way, due to the signal detected by the hose (compression) as a motor vehicle part according to the invention, a pedestrian protection airbag (eg a windshield airbag) may be fired to protect a pedestrian falling on a hood or car window from injury , In a collision-damping component arrangement according to the invention, a second energy absorption part is furthermore arranged in front of the first energy absorption part in the vehicle longitudinal direction, the second energy absorption part being designed and arranged such that it has at least partial forces acting on the second energy absorption part in the longitudinal direction of the motor vehicle Compression of the first energy absorption part causes. In other words, in the component arrangement according to the invention, two different energy absorption parts are arranged "in series". This makes it possible to provide a component arrangement by selecting at least one energy absorption part with a small space requirement, which overall has a reduced space requirement and yet meets high requirements for pedestrian protection. Due to the arrangement of at least two energy absorption parts "in series", the total energy absorption caused by the first energy absorption part and the second energy absorption part is not necessarily reduced. It may even be increased if the second energy absorption part allows greater energy absorption than exclusive use of the first energy absorption part over the same "energy absorption length". This will be explained in detail in connection with the figures. Under energy absorption is present in particular the conversion of kinetic energy by plastic deformation of components understood, such. As compression, bending, torsion including bursting of elements in two or more parts (with and without predetermined breaking points).

In a further practical embodiment of a component arrangement according to the invention, the second energy absorption part is designed such that when the energy absorption is intended, the compression of the first energy absorption part begins before the energy absorption by the second energy absorption part is completed. This also includes the possibility that the energy absorption of the first energy absorption part begins before the energy absorption of the second energy absorption part has begun. Such an arrangement has the advantage that the sensing element, which is functionally connected to the first energy absorption part, detects a corresponding collision early in the event of a collision that causes an energy absorption (ie force from the front of the motor vehicle) and thus early Movement of a motor vehicle part, such as the employment of an engine hood or the ignition of a windshield, can cause.

In a further practical embodiment of a component arrangement according to the invention, a front side of the first energy absorption part is arranged at least partially immediately adjacent to a rear side of the second energy absorption part, so that a contact region exists between the first energy absorption part and the second energy absorption part. Preferably, such a contact area is flat and has an extension of at least several centimeters (preferably several decimeters) in the vehicle transverse direction and in the vehicle vertical direction. Further preferably, such a contact area, viewed in the vehicle vertical direction, is at the same height as a sensing element arranged behind the contact area. In a particularly preferred embodiment, there is a full-surface contact between the front of the first energy absorption part and the back of the second energy absorption part, so that in case of a force acting in the vehicle longitudinal direction from the front of the motor vehicle in a relative movement between the first energy absorption part and the second energy absorption part, the second energy absorption part over the entire surface is detected by the first energy absorption part. This design has the advantage that the functional reliability of a component arrangement according to the invention is particularly high, since in this case it is ensured even with relative movements between the first energy absorption part and the second energy absorption part in the vehicle vertical direction that the second energy absorption part will at least partially lead to a compression of the first energy absorption part ,

• a) das Verhältnis zwischen Ausgangslänge und Stauchungslänge des ersten Energieabsorptionsteils l_A1/l_S1 kleiner ist als das Verhältnis zwischen Ausgangslänge und Stauchungslänge des zweiten Energieabsorptionsteils l_A2/l_S2 und/oder
• b) die Stauchungslänge des ersten Energieabsorptionsteils l_S1 größer ist als die Stauchungslänge l_S2 des zweiten Energieabsorptionsteils.

In further practical embodiments of a component arrangement according to the invention, the first energy absorption part and the second energy absorption part in the vehicle longitudinal direction, when intended for energy absorption, are compressed from an initial length l _A to a compression length l _S in the longitudinal direction,

• a) the ratio between the initial length and compression length of the first energy absorption part l _A1 / l _{S1 is} smaller than the ratio between the initial length and compression length of the second energy absorption part l _A2 / l _S2 and / or
• b) the compression length of the first energy absorption part l _{S1 is} greater than the compression length l _{S2 of} the second energy absorption part.

The length referred to above as the compression length of an energy absorption part is often referred to as block length, in particular if the energy absorption part is a planar part which is compressed by stopping or compressing to a length which is greater than 10 percent of the initial length l _A. In other words, the above-described condition of (a) means that the second energy absorption part is an energy absorption part which is compressed more than the first energy absorption part. This can be done by selecting a more compressible material or by choosing an energy absorption part with a different energy absorption mechanism.

The above-mentioned condition according to b) relates to the absolute compression length of the first energy absorption part. This condition is due to the fact that sensing elements are often integrated into energy absorption parts having a relatively large compression length (block length). In order to achieve large design and design freedom according to the invention and to be able to take account of other design-related conditions, it is preferred if the absolute compression length l _{S2 of} the second energy absorption part is smaller than the absolute compression length l _{S1 of} the first energy absorption part.

The first energy absorption part is in particular a foam part into consideration. Such foam parts are not only available inexpensively, but also allow a simple and inexpensive way to embed a sensing element or to arrange immediately adjacent. When energy is absorbed by the foam member, compression occurs which also results in compression of the embedded or immediately adjacent sensing element. This compression can be used to control the movements of a motor vehicle part. In a particularly practical embodiment of a second energy absorption part, the latter has a contact surface extending in the vehicle transverse direction and in the vehicle vertical direction to the first energy absorption part which, upon relative approach of the first energy absorption part to the second energy absorption part with a contact surface of the first energy absorption part extending in the vehicle vertical direction and in the vehicle transverse direction Plant comes. In this embodiment, the first energy absorption part and the second energy absorption part are not initially contacted, but are designed so that they are also "in series" and relative movement of the second energy absorption part toward the first energy absorption part results in the first energy absorption part absorbing energy early and in particular a sensing element can detect energy absorption at an early stage.

The second energy absorption part is preferably designed as a deformation element extending in the vehicle longitudinal direction. As an example of such a deformation element, reference is made in particular to elements that deform by (in particular plastic) bending and - optionally subsequent failure - and thus absorb energy. Such elements are also referred to in the art as buckling elements.

In another practical embodiment of a component arrangement according to the invention, a contact surface formed on the second energy absorption part is formed integrally with the deformation element. Alternatively, a contact surface can also be produced as a separate element and firmly connected to the deformation element. Which production method is preferred in an individual case depends in particular on the type of production. In the case of energy absorption parts produced by the plastic injection molding process, the integral formation of a contact surface on the deformation element is preferred.

The invention can be realized in a particularly cost-effective and functionally advantageous manner if at least one rib of a radiator grille of a motor vehicle is formed as part of the second energy absorption part. In this case, forces acting in the region of the front side of the motor vehicle can be used directly for energy absorption of the second energy absorption part and of the first energy absorption part "connected in series" behind it. In this case, a particularly early detection of a collision by means of a sensing element is possible.

As Sensierelement such elements are preferably used, which detect at least one mechanical characteristic. In this regard, reference is made, in particular, to pressure hoses known from the prior art with a connected actuator, to force measuring foils, to optical waveguides and to other mechanical components which make it possible to detect the compression of an energy absorption part, in particular of the first energy absorption part, and depending on this detection To control movements of a motor vehicle part. The detection of at least one mechanical parameter is preferred because purely electronic parameters (eg electronic detection of acceleration and vehicle speed) are not suitable in a particular case, the collision of a pedestrian from the collision with other obstacles and / or measurement errors or measurement inaccuracies to distinguish.

As already mentioned, it is preferred if the sensing element is provided for controlling the installation of an engine hood of a motor vehicle and / or for triggering at least one pedestrian protection airbag. Pedestrian protection airbags are understood in particular as those airbags that deploy outside the motor vehicle in the region of the outer skin of a body in order to cushion the impact of a pedestrian on the outer skin.

A component assembly according to the invention has particular advantages when viewed in the vertical direction of the vehicle below the cross member, another cross member is arranged, in particular a cross member, which is viewed in the vertical direction of the vehicle at the same height as arranged in the vehicle longitudinal direction in front bumper. In such a case, the design of a component arrangement according to the invention in the region of the upper cross member to any existing between the lower cross member and the front bumper existing free spaces can be adjusted insofar as the sum of the compression length of the first energy absorption part and the second energy absorption part is selected so that In the case of a pedestrian impact results in a knee angle of a pedestrian, which is as low as possible. This will be explained in detail in connection with the description of the figures. A component arrangement according to the invention has particular advantages when the free space between the lower cross member and a front-mounted bumper extends over at least 50 mm in the vehicle longitudinal direction. In a particularly preferred embodiment, the length of the free space in the longitudinal direction between 80 mm and 120 mm, more preferably between 100 mm and 120 mm. In this case, it is preferable if the first energy absorption part and the second energy absorption part in the undeformed state have a total length of about 30 mm to 70 mm and in the deformed state a compression length (block length) of a total of about 10 mm to 20 mm. This results in an energy absorption length from the front edge of the first energy absorption part to the vehicle longitudinal direction behind the following cross member of about 70 mm and a minimum compression length of 10 mm (70 mm-60 mm). The maximum plastic deformation of the first and second energy absorption part in front of the cross member thus amounts to a maximum of 60 mm in this example.

The first energy absorption element and the second energy absorption element preferably extend over at least 50 percent of the entire vehicle width (without exterior mirrors), more preferably over at least 70 percent and more preferably over at least 80 percent of the vehicle width, in particular across the width of a radiator grille, which is often between the Front headlamps of a motor vehicle is located.

Further details of a practical embodiment are described below in connection with the drawings. Show it:

1 An embodiment of an impact-damping component arrangement according to the invention in a schematic representation in a side view,

2 the in 1 marked with II area in an enlarged view,

3 a front end of a motor vehicle with the from the 1 and 2 Component assembly according to the invention immediately before the impact of a Beinimpaktors and

4 the in 3 shown front of a motor vehicle immediately after the impact of a leg impactor.

1 shows an impact-damping component assembly according to the invention 10 in the area of a front end 12 a motor vehicle 14 , In 1 is from the front end 12 the hood 16 , A schematically illustrated contour of a radiator grille 18 as well as a bumper 20 to recognize. The hood 16 , the radiator grille 18 and the bumper 20 can also be used as the outer skin of the motor vehicle 14 be designated.

As in particular in 1 can be seen, is in the vehicle vertical direction (z-direction) viewed at the same height of the radiator grille 18 an upper cross member 22 , In the vehicle longitudinal direction (x-direction) considered immediately in front of the cross member 22 is the first energy absorption part 24 a foam part 26 arranged. Inside the foam part 26 is as a sensing element 28 a hose 30 arranged, which extends in the vehicle transverse direction (y-direction) and viewed in the vehicle longitudinal direction (x-direction) immediately before the upper cross member 22 is positioned. The upper cross member 22 serves as an abutment for the hose 30 , Using the sensing element 28 be in the vehicle longitudinal direction (x-direction) on the first energy absorption part 24 acting forces, which lead to a compression of the first energy absorption part detected. If such forces are detected by the sensing element 28 controlled the movement of a motor vehicle part. In the present case, upon detection of a force by the sensing element 28 the hood 16 from in the vehicle longitudinal direction (x-direction) considered rear end of the hood 16 moved up to the distance of the hood 16 from the directly below the hood 16 to increase massive engine block. This may cause a possibly bouncing head (or other body part) of a pedestrian from the hood 16 softer cushioned, because the distance of the hood 16 is enlarged by the engine block or other solid component in the event of an impact.

Immediately before the first energy absorption part 24 there is a second energy absorption part 32 , The second energy absorption part 32 is in the embodiment shown an integrally formed rib 34 the radiator grille 18 , The rib 34 extends from the outer contour of the motor vehicle 14 in the longitudinal direction of the vehicle 14 looks backwards to the front 36 of the foam part 26 , As in particular in 2 is clearly visible, lies a back 38 of the second energy absorption part 32 on the front side 36 of the first energy absorption part 24 immediately.

In 2 is the second energy absorption part 32 so shown that it is made of a first single element 40 and a second single element 42 exists, which are firmly connected. The first single element 40 extends forward and is considered one of the front 36 of the motor vehicle 14 made of recognizable Köhlrippe. The second single element 42 initially extends on the inside along the first single element 40 and from a kink 44 only in vehicle vertical direction over the entire height of the front 36 of the first energy absorption part 24 ,

In 2 are the initial length l _{A1 of} the first energy absorption part 24 and the output length l _{A2 of} the second energy absorption part 32 shown, as the initial length in 2 just up to the front 36 of the first energy absorption part 24 extending length was assumed. In 2 Furthermore, the length l _{D is} entered, which the deformation path of the first energy absorption part 24 and the second energy absorption part 32 equivalent.

In the 3 and 4 are in addition to the above-mentioned elements still a lower cross member 46 as well as a leg impactor 48 shown. Furthermore, the front wheel 56 of the motor vehicle 14 to recognize.

As in 3 can be seen, is located between the lower cross member 46 and the bumper 20 a free space with the length l _F. This clearance l _F is approximately 100 mm in the illustrated embodiment. This results in the case of a pedestrian impact against the front end 12 of the motor vehicle 14 which is caused by the leg impactor 48 is simulated, due to the clearance at the height of the joint 50 indicated knee in the longitudinal direction can penetrate relatively far into the body.

The component assembly according to the invention 10 allows it in case of an impact of a leg impactor 48 an upper part 52 of the leg impactor 48 by energy absorption (plastic deformation) in the vehicle longitudinal direction can also penetrate far into the body, so that the resulting angle α (this simulates the knee angle of a colliding with the motor vehicle pedestrian) between the upper part 52 and a lower part 54 of the leg impactor 48 small and thus remains in a knee-protecting area (see 4 ).

The invention makes it possible by designing a component arrangement according to the invention, in particular in vehicles with the above-described free spaces l _F between a bumper 20 and a lower cross member 46 to keep the angle α (knee bending angle) that is relevant for pedestrian impact simply and cost-effectively within a permissible range. Preferably, a component arrangement according to the invention is designed so that at a pedestrian impact a knee bending angle α is smaller than 19 °, the ligament strains in the inner and outer bands are smaller than 19 mm and the ligament strains in the cruciate ligament are smaller than 10 mm.

The features of the invention disclosed in the present description, in the drawings and in the claims may be essential both individually and in any desired combinations for the realization of the invention in its various embodiments. The invention is not limited to the described embodiments. This can be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art.

LIST OF REFERENCE NUMBERS

10

Impact-absorbing component assembly

12

front end

14

motor vehicle

16

Engine Hood

18

Radiator grille

20

bumper

22

upper cross member

24

first energy absorption part

26

foam part

28

sensing element

30

tube

32

second energy absorption part

34

rib

36

front

38

back

40

first single element

42

second single element

44

kink

46

lower cross member

48

Beinimpaktor

50

joint

52

upper part (of the leg impactor)

54

lower part (of the leg impactor)

56

front

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 102004024468 A1 [0002]
• DE 102006030504 A1 [0003]

Claims (10)

Impact-damping component arrangement in the region of a front end ( 12 ) of a motor vehicle ( 14 ) with a cross member ( 22 ), viewed in the vehicle longitudinal direction in front of the cross member ( 22 ) arranged first energy absorption part ( 24 ), wherein the first energy absorption part ( 24 ) an integrated or immediately adjacent sensing element ( 28 ) for controlling the movement of a motor vehicle part in dependence on the state of the first energy absorption part ( 24 ), characterized in that viewed in the vehicle longitudinal direction before the first energy absorption part ( 24 ) a second energy absorption part ( 32 ), wherein the second energy absorption part ( 32 ) is designed and arranged such that it is in the longitudinal direction of the motor vehicle ( 14 ) from the front to the second energy absorption part ( 32 ), sufficiently large forces an at least partial compression of the first energy absorption part ( 24 ) causes. Component arrangement according to the preceding claim, characterized in that the second energy absorption part ( 32 ) is designed such that at normal energy absorption the compression of the first energy absorption part ( 24 ) begins before the energy absorption by the second energy absorption part ( 32 ) is completed. Component arrangement according to one or more of the preceding claims, characterized in that a front side ( 36 ) of the first energy absorption part ( 24 ) at least partially immediately adjacent to a rear side ( 38 ) of the second energy absorption part ( 32 ) is arranged. Component arrangement according to one or more of the preceding claims, characterized in that the first energy absorption part ( 24 ) and the second energy absorption part ( 32 ) considered in the vehicle longitudinal direction at normal energy absorption from an initial length l _A to a compression length l _S are compressed in the longitudinal direction, wherein a) the ratio between initial length and compression length l _A1 / l _{S1 of} the first energy absorption part ( 24 ) is smaller than the ratio between initial length and compression length l _A2 / l _{S2 of} the second energy absorption part ( 32 ) and / or b) the compression length l _S1 , of the first energy absorption part ( 24 ) is greater than the compression length l _{S2 of} the second energy absorption part ( 32 ). Component arrangement according to one or more of the preceding claims, characterized in that the first energy absorption part ( 24 ) a foam part ( 26 ) and / or the second energy absorption part ( 32 ) extending in the vehicle transverse direction and in the vehicle vertical direction contact surface to the first energy absorption part ( 24 ), which upon relative approach of the first energy absorption part ( 24 ) to the second energy absorption part ( 32 ) with a contact surface of the first energy absorption part extending in the vehicle vertical direction and in the vehicle transverse direction (US Pat. 24 ) comes to the plant. Component arrangement according to one or more of the preceding claims, characterized in that the second energy absorption part ( 32 ) is formed as a deforming element extending in the vehicle longitudinal direction and / or a) on the second energy absorption part ( 32 ) formed contact surface is integrally formed on the deformation element or b) formed a contact surface as a separate element and is firmly connected to the deformation element. Component arrangement according to one or more of the preceding claims, characterized in that at least one rib ( 34 ) of a radiator grille ( 18 ) as a component of the second energy absorption part ( 32 ) is trained. Component arrangement according to one or more of the preceding claims, characterized in that the sensing element ( 28 ) is a component that detects at least one mechanical parameter. Component arrangement according to one or more of the preceding claims, characterized in that the sensing element ( 28 ) for controlling the installation of a bonnet ( 16 ) of a motor vehicle ( 14 ) and / or provided for triggering at least one pedestrian protection airbag. Component arrangement according to one or more of the preceding claims, characterized in that viewed in the vehicle vertical direction below the cross member ( 22 ) another cross member ( 46 ) is arranged.

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