Crash box, bumper assembly and method for producing bumper assembly

Abstract

The invention relates to a crash box for a bumper assembly of a motor vehicle, said crash box having an outer hollow chamber, an inner hollow chamber, a vehicle-side end section and a bumper-side front section, the outer hollow chamber is connected to the inner hollow chamber and forms a closed multi-chamber profile, and in the bumper side front section, the outer hollow chamber is separated from the inner hollow chamber and is spaced apart from the inner hollow chamber. The crash box is characterized in that in the end section, the outer hollow chamber and the inner hollow chamber each have a partition wall, which delimits the outer hollow chamber and the inner hollow chamber on the inside, the partition walls are preferably spaced apart from each other and form a further hollow chamber in the end section together with an upper bridge and a lower bridge that connect the outer hollow chamber and the inner hollow chamber.

Description

Technical Field

[0001] The invention relates to a crash box for a bumper assembly of a motor vehicle, as well as a bumper assembly of a motor vehicle having two such crash boxes and a method for producing such a bumper assembly. Background Art

[0002] Crash boxes and bumper assemblies are generally used in all motor vehicles and have the task of absorbing the energy introduced via the bumper assembly in the crash box by corresponding folding or deformation of the crash box and conducting the excess energy into the frame or vehicle longitudinal beams of the motor vehicle in order to conduct the energy introduced into the motor vehicle by the collision around the passenger compartment and to minimize damage to the passenger compartment and thus reduce the risk of injury to the occupants.

[0003] In typical tests such as the following, the folding of the crash box must correspond to corresponding specifications: the bumper assembly must pass the typical test in order for the vehicle to pass the safety test. It is therefore important that the force level can be matched to the maximum peak value when the crash box is folded. However, in addition to matching the profile geometry of the wall thickness of the trigger embossing and its position, number and depth, further precautions must be taken in order to optimize the folding of the crash box and the energy absorption and energy conduction.

[0004] In particular, the joint connection between the crash box and the cross member of the bumper assembly must not be damaged or destroyed in the event of a crash so that the crash box folds according to the specification and excess energy is transferred to the frame of the motor vehicle or to the vehicle longitudinal beams of the motor vehicle.

[0005] For example, a bumper assembly with a crash box is known from the document WO 2007 / 121896 A2, wherein the crash box there is bent toward the middle area of ​​the crossbar of the bumper assembly there and is screwed to the crossbar there. However, in this bumper assembly, in the event of a collision in which the main force is introduced between two crash boxes into the crossbar of the bumper assembly, the screwing of the crash box to the crossbar is subjected to extremely high loads, so that there is the risk that the screwing is damaged and possibly even completely destroyed in the event of a collision, and therefore it is no longer possible to ensure that the crash box folds in accordance with a predefined regulation. Therefore, it is no longer guaranteed that the collision energy is directed to the vehicle frame around the passenger compartment. As a result, the risk of injury to the personnel in the passenger compartment is significantly increased.

[0006] Furthermore, WO 94 / 27841 A1 discloses a bumper assembly in which the contact surface between the crash box and the cross member of the bumper assembly is reduced in the joint region. In this case, in the event of a collision in which the main forces are introduced between the two crash boxes into the cross member of the bumper assembly, the joint region is also subjected to extremely high loads, which can lead to damage in the joint connection and possibly to the destruction of the joint connection. Therefore, in this bumper assembly, a targeted conduction of the collision energy around the passenger compartment into the vehicle frame is no longer guaranteed. As a result, the risk of injury to people in the passenger compartment is significantly increased.

[0007] In addition, EP 0 894 675 A1 shows a bumper assembly with a crash box consisting of a single-chamber profile. Here, the inner and outer walls of the crash box are bent away from the crash box and joined to the crossbeam of the bumper assembly like the lower and upper walls of the crash box. Here, in the case of a collision in which the main force is introduced into the crossbeam of the bumper assembly between two crash boxes, the joining area is also subjected to extremely high loads, which are distributed over a larger area of ​​the crossbeam, but still cause damage in the joining connection and may cause the destruction of the joining connection. This is especially because the folding characteristics of the hollow chamber of the crash box that is open to the crossbeam are significantly more unfavorable and have a lower predictability. Therefore, in this bumper assembly, it is no longer guaranteed that the collision energy is directed to the vehicle frame around the passenger compartment. As a result, in this bumper assembly, the risk of injury to the personnel in the passenger compartment is significantly increased again.

[0008] Furthermore, US 2015 / 108775 A1 shows a crash box according to the preamble of claim 1. However, there is still a need for improvement in this crash box as well, in order to make the joint connection between the crash box and the cross member of the bumper assembly more resistant to destruction in the event of a collision.

[0009] In general, therefore, there is still an increasing need to make the joint connection between the crash box and the cross member of the bumper assembly more resistant to destruction in the event of a crash in which major forces are introduced between two crash boxes into the cross member of the bumper assembly. In particular, welded connections should be avoided, since cracks may occur in the event of a crash in the welded connection or in its heat-affected zone, which may lead to failure of the crash management system of the bumper assembly. Summary of the invention

[0010] The object of the present invention is therefore to provide a crash box for a bumper assembly of a motor vehicle, wherein the folding in the event of a collision in which the main forces are introduced between two crash boxes into the cross member of the bumper assembly and the energy conduction into the motor vehicle frame are further optimized and improved, wherein the probability of failure of the crash management system or of the bumper assembly and the probability of destruction of the joint connection between the crash box and the cross member of the bumper assembly are significantly minimized compared to the prior art. In addition, the object of the present invention is to provide a corresponding bumper assembly with such a crash box and a method for producing such a bumper assembly.

[0011] With regard to a crash box, this object is achieved by a crash box having all the features of claim 1. With regard to a bumper assembly, this object is achieved by a bumper assembly having all the features of claim 11. With regard to a method for producing a bumper assembly, this object is achieved by a method having all the features of claim 15. Advantageous embodiments of the invention are to be found in the dependent claims.

[0012] The crash box of the bumper assembly for a motor vehicle according to the present invention is characterized in that the crash box has at least one outer hollow chamber and at least one inner hollow chamber and a vehicle-side end section and a bumper-side front section, wherein in the vehicle-side end section, the at least one outer hollow chamber is connected to the at least one inner hollow chamber and forms a closed multi-chamber profile, while in the bumper-side front section, the at least one outer hollow chamber is separated and spaced apart from the at least one inner hollow chamber. Here, in the end section, the at least one outer hollow chamber and the at least one inner hollow chamber each have a partition wall, which delimits the at least one outer hollow chamber and the at least one inner hollow chamber on the inside, wherein the partition walls are preferably spaced apart from each other and form a further hollow chamber in the end section together with an upper bridge and a lower bridge, which connect the at least one outer hollow chamber and the at least one inner hollow chamber. A crash box of this type can be produced in a simple manner from a multi-chamber hollow profile, wherein a further hollow chamber is arranged between at least one outer hollow chamber and at least one inner hollow chamber. For this purpose, a gap is introduced in a simple manner in the front region of the multi-chamber hollow profile between at least one outer hollow chamber and at least one inner hollow chamber in the further hollow chamber. This results in a crash box that has a closed inner hollow chamber and an outer hollow chamber in the front region. Subsequently, the connection region of the crash box to the crossbeam can also be widened, for example by bending or folding the closed inner hollow chamber and / or the outer hollow chamber.

[0013] The configuration of the crash box according to the invention makes it possible that, in the event of a collision in which the main forces are introduced between the two crash boxes into the cross member of the bumper assembly, both the joint connection of the at least one outer hollow chamber and the joint connection of the at least one inner hollow chamber are subjected to significantly less load than in the case of the crash boxes known from the prior art. As a result, the risk of failure of the crash management system of the bumper assembly and destruction of the joint connection is significantly minimized, because the at least one outer hollow chamber and the at least one inner hollow chamber are subjected to load independently of each other due to their separation and spacing in the front area, and therefore there are independent energy dissipation paths. Through these different energy dissipation paths, even more targeted folding of the crash box can be achieved in such a collision, and the introduction of excess collision energy around the passenger compartment into the vehicle body can be achieved. As a result, the safety of the occupants in the passenger compartment is significantly increased by the crash box according to the invention, because the risk of failure of the crash management system and uncontrolled collapse of the bumper assembly is significantly minimized. This type of crash box according to the invention is particularly effective if a welded connection is used as a joining connection, because a large-area material-locked connection is achieved between the cross member and the crash box, which makes it possible to calculate and predict the targeted folding of the crash box and the introduction of excess crash energy around the passenger compartment into the vehicle body in such a crash situation particularly well. Particularly advantageous in the crash box according to the invention is its one-piece design, which also contributes to improved performance in the event of a crash, because the number of weld seams or their length can also be significantly minimized. This allows a lower heat input when producing the welded connection, so that overall the risk of cracks in the heat-affected zone can be minimized. The one-piece design of the crash box also allows for less parts logistics.

[0014] Here, according to an advantageous first configuration, two alternative embodiments are possible. On the one hand, in the vehicle-side end section, at least one outer hollow chamber can be connected to at least one inner hollow chamber in the horizontal direction and form a closed multi-chamber profile, while in the bumper-side front section, at least one outer hollow chamber is separated and spaced apart from at least one inner hollow chamber in the horizontal direction. On the other hand, in the vehicle-side end section, at least one outer hollow chamber can be connected to at least one inner hollow chamber in the vertical direction and form a closed multi-chamber profile, while in the bumper-side front section, at least one outer hollow chamber is separated and spaced apart from at least one inner hollow chamber in the horizontal direction.

[0015] According to another advantageous embodiment of the invention, both the at least one inner hollow chamber and the at least one outer hollow chamber are provided over their entire longitudinal extension from the bumper-side end to the vehicle-side end. The crash box according to the invention is designed to be closed on the upper side. Such a closed hollow profile has particularly good and predictable folding behavior in the event of a collision and can particularly well direct excess collision energy around the passenger compartment into the vehicle body. The crash box according to the invention thus contributes to increasing the safety of people in the passenger compartment of a motor vehicle.

[0016] Alternatively, it is also possible that at least one outer hollow chamber or at least one inner hollow chamber is constructed openly in the front section on its longitudinal extension, in particular as an open C-shaped profile. In such a configuration of the crash box, a particularly good and predictable folding performance of the crash box is also provided, so that this type of crash box also introduces excess collision energy particularly well into the vehicle body around the passenger compartment. In particular, this is particularly applicable when at least one outer hollow chamber or at least one inner hollow chamber is constructed openly to at least one other hollow chamber in its longitudinal extension in the front section. Therefore, this type of configuration of the crash box also helps to improve the safety of people in the passenger compartment of the motor vehicle.

[0017] According to a particularly advantageous embodiment of the crash box according to the invention, at least one outer hollow chamber has a longitudinal axis in the front section, which forms an angle α of less than 40° with respect to the longitudinal axis of at least one inner hollow chamber, wherein the angle α is preferably designed to be greater than 3°. Due to this embodiment of the crash box according to the invention, at least one inner hollow chamber and at least one outer hollow chamber are spaced farther and farther apart from each other in the front region, wherein the spacing increases linearly as the end of the crash box on the bumper side approaches. As a result, the crash box is significantly widened in its joining region with the cross member. This results in a significant reduction in the forces acting on the joining connection and, in particular, the forces acting on the weld seam when a welded connection is used. Therefore, due to this embodiment of the crash box according to the invention, an uncontrolled collapse of the crash management system or a destruction of the joining connection between the crash box and the cross member in the event of a collision in which the main forces are introduced between the two crash boxes into the cross member of the bumper assembly is prevented, which in turn improves the safety of people in the passenger compartment of a motor vehicle having such a crash box.

[0018] Alternatively, it can also be provided that, in the front section, at least one outer hollow chamber and at least one inner hollow chamber have a spacing that increases continuously toward the bumper side end, without the corresponding longitudinal axis of the hollow chamber forming a constant angle. In particular, at least one inner hollow chamber and / or at least one outer hollow chamber can be bent accordingly in the front region. Here, the bend can have a variety of forms, so that not only a bending radius can exist, but also a continuously increasing bend can exist. It is also possible that the bend changes direction in its direction. By this type of configuration of the crash box according to the present invention, at least one inner hollow chamber and at least one outer hollow chamber are also spaced farther and farther apart from each other in the front region, but wherein, the closer to the bumper side end of the crash box, the linear increase of the spacing of the hollow chambers does not occur. However, here, the crash box is also significantly widened in its joint region with the crossbeam. Here, this also leads to a significant reduction in the forces acting on the joint connection and, in particular, the forces acting on the weld seam when a welded connection is used. Thus, by means of this embodiment of the crash box according to the invention, an uncontrolled collapse of the crash management system or a destruction of the joint connection between the crash box and the cross member in the event of a crash in which major forces are introduced between two crash boxes into the cross member of the bumper assembly is also prevented, which in turn increases the safety of people in the passenger compartment of a motor vehicle having such a crash box.

[0019] It has proven to be particularly advantageous here if the front section extends over 1 / 5 to 2 / 3 of the total length of the crash box. Such a design of the crash box achieves particularly good crash management of the bumper assembly. This results in particularly good and predictable folding behavior in the event of a crash, and particularly good introduction of excess crash energy around the passenger compartment into the vehicle body. This design of the crash box according to the invention therefore contributes to increasing the safety of people in the passenger compartment of a motor vehicle.

[0020] In order to achieve a separation and spacing of at least one inner hollow chamber and at least one outer inner hollow chamber in the front region, at least one outer hollow chamber is separated from at least one inner hollow chamber in the front region by a gap, which is preferably rounded toward the end section, in particular rounded by a radius, wherein the radius corresponds at least to the wall thickness of the hollow chamber in the end section. The introduction of such a gap can be achieved particularly simply and effectively, in particular in terms of tool technology, by using a milling tool or a punching tool. In particular, with the aid of such a processing technology or processing tool, a corresponding rounding or radius can be produced simply and accurately toward the end section.

[0021] Alternatively, it is possible that in the front section a further hollow chamber is arranged in the gap between the inner hollow chamber and the outer hollow chamber, so that separate gaps are arranged between the inner hollow chamber and the further hollow chamber and between the further hollow chamber and the outer hollow chamber.

[0022] In order to achieve particularly good introduction of excess impact energy and to optimize the folding behavior of the crash box, the hollow chamber has desired deformation points on the inside and / or on the outside in the front section and / or in the end section.

[0023] The following configuration of the present invention is also directed in the same direction: according to this configuration, in the front section, a bridging portion is arranged on the hollow chamber, in particular a bridging portion constructed on the entire longitudinal extension of the front section, in which a crimp is arranged as a deformation element, wherein the crimp preferably extends (fortsetzen) into the partition wall and the upper and / or lower limiting wall of the hollow chamber.

[0024] According to another advantageous embodiment of the crash box according to the invention, the hollow chamber has a constant width of at least 20 mm over its entire longitudinal extension from the vehicle-side end to the bumper-side end. This constant width allows particularly good design of the crash management, since the folding of the crash box and the introduction of excess crash energy around the passenger compartment into the vehicle body can be particularly predicted or calculated.

[0025] The bumper assembly according to the invention for a motor vehicle has two crash boxes as described above, which are connected to one another via at least one cross member. With such a bumper assembly, particularly good crash management can be achieved, wherein the folding of the crash boxes and the introduction of excess crash energy around the passenger compartment into the vehicle body can be predicted or calculated, whereby the safety of the people in the passenger compartment is significantly increased.

[0026] Even though the directional specifications concerning the inner and outer hollow chambers of the crash box are to be understood as referring to the installation position and the vehicle coordinate lines (X, Y, Z), it is also possible within the scope of the invention to use a crash box which is installed rotated by 90° about the longitudinal axis (X) of the vehicle so that the inner and / or outer hollow chambers are inclined in the vehicle height direction instead of towards the side of the vehicle.

[0027] Therefore, alternatively, the bumper assembly according to the present invention may be constructed such that

[0028] a) at least one outer hollow chamber is arranged closer to the end of at least one cross-member than at least one inner hollow chamber, or

[0029] b) The at least one outer hollow chamber of the crash box is arranged above the at least one inner hollow chamber.

[0030] According to another advantageous embodiment of the invention, the height of the at least one cross member is greater than the cross-sectional height of the vehicle end section of the crash box, wherein at least one outer hollow chamber of the crash box is arranged above at least one inner hollow chamber and supported on an upper fastening region of the at least one cross member, and at least one inner hollow chamber is supported on a lower fastening region of the at least one cross member.

[0031] It has proven to be advantageous here if the crash box is joined, preferably screwed or integrally joined, in particular welded, to the cross member. This type of joint connection can be produced simply and economically advantageously.

[0032] It is also advantageous that the crash box is designed to be connectable, in particular weldable or screwable, in particular screwable to each other via a flange plate, with the end section of the motor vehicle, in particular with the longitudinal beam of the motor vehicle. This type of joint connection can also be produced simply and economically advantageously.

[0033] The method according to the invention for producing the above-described bumper assembly having two above-described crash boxes has the following method steps:

[0034] a) providing two multi-chamber hollow profiles having at least one outer hollow chamber and at least one inner hollow chamber,

[0035] b) introducing a slot into a front section of the multi-chamber hollow profile for separating and spacing at least one outer hollow chamber from at least one inner hollow chamber and for producing two crash boxes,

[0036] c) Provide two collision boxes,

[0037] d) Joining the two crash boxes to at least one cross member.

[0038] Here, the joining can be achieved by means of different joining methods, such as screwing and in particular welding. Here, there are various possibilities for connecting the crossbeam and the crash box. On the one hand, at least one inner hollow chamber and an outer hollow chamber can have overlapping front areas, by means of which the crash box grips the crossbeam above and below, and by means of which the crash box can be joined, in particular screwed and / or welded, to the crossbeam of the bumper assembly. On the other hand, at least one inner hollow chamber and an outer hollow chamber can be welded directly to the crossbeam. Here, on the one hand, it is possible to weld the at least one inner hollow chamber and an outer hollow chamber directly to the rear wall of the crossbeam. On the other hand, the rear wall of the crossbeam can also have a through-hole, through which at least one inner hollow chamber and an outer hollow chamber can pass, so as to be subsequently welded to the front wall of the crossbeam. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Further objects, advantages, features and application possibilities of the present invention are apparent from the following description of the exemplary embodiments according to the drawings. All features described and / or illustrated in the form of images constitute the subject matter of the present invention individually or in any meaningful combination, regardless of their summary in the claims or their reference relationships.

[0040] The accompanying drawings show:

[0041] Figure 1 A first exemplary embodiment of a crash box according to the invention is shown in a plan view from below.

[0042] Figure 2 The bumper-side end of the crash box is shown in a perspective view. Figure 1 An embodiment of

[0043] Figure 3 An embodiment of a crash box according to the invention is shown in a perspective view of one end of a bumper assembly, in which the bumper assembly has been connected to a Figure 1 and 2 The collision box is connected,

[0044] Figure 4 A further embodiment of a bumper assembly according to the invention is shown in a view from above of one end of the bumper assembly, in which the bumper assembly has been joined to a crash box according to the invention.

[0045] Figure 5a shows a cross-sectional view of a front section of an exemplary embodiment of a crash box according to the invention,

[0046] Figure 5b Show Figure 5a A cross-sectional view of an end section of an exemplary embodiment of a crash box of

[0047] Figure 6a shows a cross-sectional view of a front section of an exemplary embodiment of a crash box,

[0048] Figure 6b Show Figure 1 and 2 of the collision box or Figure 5a A cross-sectional view of an end section of an exemplary embodiment of a crash box of

[0049] Figure 7a shows a cross-sectional view of a front section of a further exemplary embodiment of a crash box according to the invention,

[0050] Figure 7b Show Figure 7a A cross-sectional view of an end section of an exemplary embodiment of a crash box of

[0051] Figure 8 The left end of the bumper assembly is shown in a view from above of an embodiment of the bumper assembly according to the invention at the beginning of a center impact between two crash boxes of the bumper assembly.

[0052] Fig. 9 The view from above of one end of the bumper assembly shows the central impact between two crash boxes of the bumper assembly during a center impact. Figure 8 An embodiment of a bumper assembly according to the present invention,

[0053] Fig.10 A further embodiment of a crash box according to the invention is shown in a top view from one side.

[0054] Fig.11 An embodiment of a bumper assembly according to the present invention is shown. DETAILED DESCRIPTION

[0055] Figure 1 A first embodiment of a crash box 1 according to the invention is shown in a top view from below. As can be seen therein, the crash box 1 comprises an outer hollow chamber 5 and an inner hollow chamber 7, which extend from the vehicle-side end 4 to the bumper-side end 3. The two hollow chambers 5 and 7 are connected in the vehicle-side end section 9 by means of a lower bridge 16.

[0056] At the end of the lower bridge 16 pointing toward the bumper-side end 3, the lower bridge has a radius 17 toward its end. From here, the two hollow chambers 5 and 7 are separated and spaced apart from each other by a gap in the horizontal direction 22 in the front section 10 on the bumper side. In this case, the gap 11 increases continuously from its end at the radius 17 of the bridge 16 pointing toward the vehicle-side end 4 of the crash box 1 toward the bumper-side end 3. The two hollow chambers 5 and 7 are therefore designed in a manner bent at an angle to each other in the front section 10, wherein the longitudinal axis 18 of the inner hollow chamber 7 forms an angle α of approximately 40° with the longitudinal axis 19 of the outer hollow chamber 5.

[0057] exist Figure 1 In the figure, a further hollow chamber 14 is also shown, which is arranged in the vehicle-side end section 9 between the inner hollow chamber 7 and the outer hollow chamber 5 and is connected by a lower bridge 16 and in Figure 2 The upper bridge 15 and the partition walls 12 and 13 are formed in Figure 2 1 shows a perspective view of the bumper-side end of the crash box 1 from above. In this case, the partition walls 12 and 13 form the inner wall between the two hollow chambers 5 and 7 in the vehicle-side end region 9 .

[0058] from Figure 2 It can also be seen in the schematic diagram that both the inner hollow chamber 7 and the outer hollow chamber 5 are designed as closed hollow chambers 5 and 7 over their entire longitudinal extension. The crash box 1 can now be joined, preferably welded, to the cross member of the bumper assembly at the bumper-side end 3 via the inner crash box 7 and the outer crash box 5. At the vehicle-side end 4, the entire crash box 1 can also be joined, especially welded, to the body of the motor vehicle, preferably to the longitudinal beam of the motor vehicle.

[0059] Now, in Figure 3 In one embodiment of a bumper assembly according to the present invention, a perspective view of one end of the bumper assembly is shown. Figure 1 and 2 A crash box 1 is shown which, in this perspective view, has been joined to a bumper assembly 2 of a motor vehicle. The joining is carried out by means of a welded connection, by means of which a weld seam 26 is formed between the cross member 20 of the bumper assembly 2 and the outer hollow chamber 5 in the bumper-side front section 10. The weld seam 26 is shown here only in the outer region, but preferably extends over the entire closed region of the hollow chamber 5 facing the cross member 20, so that the cross member 20 and the hollow chamber 5 are connected to each other in a material-locking manner over the entire circumference of the hollow chamber 5.

[0060] Likewise, the inner hollow chamber 7 in the front section 10 is joined, in particular welded, to the cross member 20 of the bumper component 2 , wherein here too a materially bonded connection is produced over the entire circumference of the hollow chamber 7 by the weld seam 27 between the cross member 20 and the hollow chamber 7 .

[0061] Now, in Figure 3 It can also be clearly seen that in the assembled state of the bumper assembly 2 according to the invention, the crash box 1 is designed such that the two hollow chambers 5 and 7 in the front region 10 are separated from one another by a gap 11, wherein the gap 11 increases continuously toward the cross member 20 of the bumper assembly 2. As a result, the entire action area of ​​the crash box 1 on the cross member 20 of the bumper assembly 2 is significantly widened, so that the energy introduced in the event of a collision is introduced into the crash box 1 via the cross member 20 over a significantly larger area, thereby achieving a significantly more favorable force distribution.

[0062] In addition, Figure 3 It can also be seen that there is another hollow chamber 14 between the inner hollow chamber 7 and the outer hollow chamber 5, which is formed by the inner partition wall 12 of the inner hollow chamber 7 and the inner partition wall 13 of the outer hollow chamber 5 as well as the upper bridge 15 and the lower bridge 16, which connect the inner hollow chamber 7 with the outer hollow chamber 5.

[0063] Furthermore, the radius 17 of the upper bridge 15 at its bumper-side end 3 can be clearly seen. In the event of a crash, the configuration of this radius allows for a better introduction of forces into the body of the vehicle and a more targeted folding of the cross member 1 .

[0064] Figure 4 A view from above shows a schematic embodiment of a bumper assembly 2 according to the invention, which has a cross member 20, which is joined to a crash box 1 according to the invention at its bumper-side end 3 with inner hollow chamber 7 and outer hollow chamber 5 via weld seams 27 and 26. At the vehicle-side end 3, the crash box 1 is likewise joined, in particular screwed or welded, to a longitudinal member 25 of the motor vehicle.

[0065] Figure 5a A cross-sectional view of a front section 10 of an exemplary embodiment of a crash box 1 according to the invention is shown. Figure 5b The cross section of the end section 9 of this embodiment is shown. It can be seen here that in this embodiment there are two closed inner hollow chambers 7 and 8 and two closed hollow chambers 5 and 6. Figure 5a In the figure, the gap 11 in the front section 10 can be seen, by which the inner hollow chambers 7 and 8 are separated and spaced apart from the outer hollow chambers 5 and 6. In this case, the inner hollow chambers 7 and 8 have a common inner partition wall 12, which points in the direction of the common inner partition wall 13 of the outer hollow chambers 5 and 6.

[0066] Now, in Figure 5b It can be seen that the two inner hollow chambers 7 and 8 are connected to the outer hollow chambers 5 and 6 in the vehicle-side end region 9 via the upper bridge 15 and the lower bridge 14. Here, the upper bridge 15 and the lower bridge 16 together with the upper bridge 15 and the lower bridge 16 form a further hollow chamber 14, which is arranged between the outer hollow chambers 5 and 6 and the inner hollow chambers 7 and 8.

[0067] In addition, Figure 5a The bridges 15' and 16' are shown in FIG. Figure 5b The bridges 15 and 16 shown in the figure protrude from the upper and lower limiting walls 30 and 31 of the hollow chambers 5 and 7 and extend from the upper limiting walls 30 and 31 of the hollow chambers 6 and 8. In these bridges 15 ′ and 16 ′, beads (not shown here) can be introduced, which extend into the partition walls 12 and 13 and the upper and lower limiting walls 30 and 31.

[0068] Figure 6a and 6b Another embodiment of a transverse box 1 according to the invention is shown, in which: Figure 6a shows a cross section of the front section 10 , Figure 6bThe cross section of the end section 9 is shown. In this embodiment, according to Figure 1 and 2 In the embodiment of the embodiment of the present invention, only one inner hollow chamber 7 and only one outer hollow chamber 5 are provided. In the cross section shown in FIG. 6 in the front section 10, the inner hollow chamber 7 and the outer hollow chamber 5 are again spaced apart and separated from each other by a gap 11. In this embodiment, the hollow chambers 5 and 7 are designed to be closed over their entire longitudinal extension, so that the inner partition walls 12 and 13 of the hollow chambers point toward each other.

[0069] In such as Figure 6a In the end section 9 shown in cross section, the inner hollow chamber 7 and the outer hollow chamber 5 are again connected to one another via an upper bridge 15 and a lower bridge 16. In this embodiment, the upper bridge 15 and the lower bridge 16 together with the inner partition walls 12 and 13 of the inner hollow chamber 7 and the outer hollow chamber 5 form a further hollow chamber 14.

[0070] and Figure 5a and Figure 5b Similar to the embodiment of Figure 6a The bridges 15' and 16' are shown in FIG. Figure 6b The bridges 15 and 16 shown in the figure protrude from the upper and lower limiting walls 30 and 31 of the hollow chambers 5 and 7 and extend through the upper limiting walls 30 and 31 of the hollow chambers 5 and 7. A bead not shown here can be introduced into these bridges 15 ′ and 16 ′, which extends into the partition walls 12 and 13 and the upper and lower limiting walls 30 and 31.

[0071] exist Figure 7a and 7b Another embodiment of a crash box 1 according to the invention is shown in cross section. Figure 7a 7 shows a cross section in the front region 10 of the crash box 1, while FIG. 8 shows a cross section in the end region 9 of the crash box 1. Figure 7b As shown, the crash box 1 again has two outer hollow chambers 5 and 6 and two inner hollow chambers 7 and 8. In this embodiment, the outer hollow chambers 5 and 6 and the inner hollow chambers 7 and 8 have a common partition wall 12. As a result, this embodiment of the crash box according to the invention does not require a separate partition wall 12 as in Figure 5b and 6b The further hollow chamber 14 is given in the embodiment of FIG.

[0072] In such as Figure 7aIn the front section 10 shown in cross section, the outer hollow chambers 5 and 6 are now designed to be open to the inner hollow chambers 7 and 8, but are also separated and spaced apart from the inner hollow chambers by gaps 11. In this embodiment, the inner hollow chambers 7 and 8 are designed as closed hollow chambers 7 and 8, wherein the inner hollow chambers have a partition wall 12 as a termination to the open outer hollow chambers 5 and 6.

[0073] Now, Figure 8 The top view of the left end of the bumper assembly shows the bumper assembly 2 according to the invention at the beginning of a central impact between two crash boxes 1 of the bumper assembly 2. It can be seen here that the cross member 20 of the bumper assembly 2 is hit by an obstacle 23 between the two crash boxes 1.

[0074] exist Figure 8 In the schematic diagram of , no force action of the obstacle 23 on the bumper assembly 2 has yet occurred, so that the crash box 1 still has its unchanged arrangement relative to the cross member 20 of the bumper assembly 2, wherein in this exemplary embodiment, a closed inner hollow chamber 7 and a closed outer hollow chamber 5 are provided. The inner hollow chamber 7 and the outer hollow chamber 5, which are separated and spaced apart from each other by the gap 11, are connected to the cross member 20 of the bumper assembly 2 in a materially bonded manner in the front region 10 via their welded connections 26 and 27.

[0075] In the end section 9 of the crash box 1 which is joined to the longitudinal beam 25 of the motor vehicle via the flange plate 29 , in the region of the inner hollow space, on its outer side, the outer wall pointing toward the center of the bumper assembly has a desired deformation point 24 .

[0076] Now, in Fig. 9 , the left end of the bumper assembly is shown from above during a center impact between two crash boxes 1 of the bumper assembly 2. Figure 8 . As can be seen, in the region of the desired deformation point 24, a targeted folding of the crash box 1 already occurs in the end region 9 of the crash box, wherein the material connection of the outer hollow chamber 5 and the inner hollow chamber 7 formed by the weld seams 26 and 27 in the front region 10 of the crash box 1 remains intact. Since the weld seams have a significantly wider point of action on the cross member 20 of the bumper assembly 2 due to the configuration of the crash box 1 according to the invention, the energy introduced into the cross member 20 is distributed over a larger area, where it is introduced into the crash box, wherein in the event of a crash, a force distribution also occurs that acts on a larger area of ​​the cross member, so that the probability of failure of the welded connection due to tearing of the weld seams 26 and 27 is significantly minimized.

[0077] Fig.10The crash box 1 according to the invention is shown in an installation position in a motor vehicle which is rotated by 90° relative to the previous embodiment, wherein the inner and outer hollow chambers 5, 7 are spaced apart from one another on the front section 10 on the cross member side not in the vehicle transverse direction 22 but in the vehicle height direction 28, so that an increasing spacing extending toward the cross member 20 is formed between the hollow chambers 5 and 7.

[0078] and Figure 4 The implementation methods are different. Fig.11 It is shown that only one of the hollow chambers, namely the outer hollow chamber 5 , is designed obliquely or angled in the cross-member-side end section 9 , whereas the inner hollow chamber 7 extends substantially continuously and straightly between the two crash box ends.

[0079] exist Fig.10 and 11 In the exemplary embodiment, a flange plate 29 is arranged at each end of the vehicle-side end section 9 in order to connect the crash box 1 to the vehicle longitudinal beam, in particular to screw it to the flange plate arranged on the vehicle longitudinal beam.

[0080] Reference numerals list

[0081] 1 collision box

[0082] 2 Bumper assembly

[0083] 3 Bumper side end

[0084] 4 Vehicle side end

[0085] 5 Hollow Chamber

[0086] 6 Hollow Chamber

[0087] 7 Hollow Chamber

[0088] 8 Hollow Chamber

[0089] 9 End section

[0090] 10Front section

[0091] 11 Gap

[0092] 12 Divider Wall

[0093] 13 Divider Wall

[0094] 14 Hollow Chamber

[0095] 15 Upper bridge

[0096] 15' bridge

[0097] 16 Lower bridge

[0098] 16' bridge

[0099] 17 Radius

[0100] 18 Vertical axis

[0101] 19 Vertical axis

[0102] 20 Beam

[0103] 21 Multi-chamber hollow profile

[0104] 22 Horizontal

[0105] 23 Obstacles

[0106] 24 Expected deformation area

[0107] 25 Stringer

[0108] 26 Weld

[0109] 27 Weld

[0110] 28 vertical direction / vehicle height direction

[0111] 29 Flange plate

[0112] 30 Boundary Wall

[0113] 31 Boundary wall

[0114] α angle

Claims

1. A crash box (1) for a bumper assembly (2) of a motor vehicle, wherein: The crash box (1) comprises at least one outer hollow chamber (5, 6) and at least one inner hollow chamber (7, 8) and a vehicle-side end section (9) and a bumper-side front section (10), wherein, in the vehicle-side end section (9), the at least one outer hollow chamber (5, 6) is connected to the at least one inner hollow chamber (7, 8) and forms a closed multi-chamber profile, and in the bumper-side front section (10), the at least one outer hollow chamber (5, 6) is separated and spaced from the at least one inner hollow chamber (7, 8), characterized in that, in the end section (9), the At least one outer hollow chamber (5, 6) and the at least one inner hollow chamber (7, 8) respectively have a partition wall (12, 13), which limits the at least one outer hollow chamber (5, 6) and the at least one inner hollow chamber (7, 8) on the inside, wherein the partition walls (12, 13) are preferably spaced apart from each other and together with an upper bridge (15) and a lower bridge (16) form a further hollow chamber (14) in the end section (9), wherein the upper bridge and the lower bridge connect the at least one outer hollow chamber (5, 6) and the at least one inner hollow chamber (7, 8).

2. The crash box according to claim 1, characterized in that: In the vehicle-side end section (9), the at least one outer hollow chamber (5, 6) is connected to the at least one inner hollow chamber (7, 8) in the horizontal direction (22) or the vertical direction (28) and forms a closed multi-chamber profile, while in the bumper-side front section (10), the at least one outer hollow chamber (5, 6) is separated and spaced apart from the at least one inner hollow chamber (7, 8) in the horizontal direction (22) or the vertical direction (28).

3. The crash box according to claim 1 or 2, characterized in that: The hollow chambers (5, 6, 7, 8) are designed to be closed over their entire longitudinal extension from the bumper-side end (3) to the vehicle-side end (4).

4. The crash box according to claim 1 or 2, characterized in that: The at least one outer hollow chamber (5, 6) or the at least one inner hollow chamber (7, 8) is designed to be open in its longitudinal extension in the front section (10), preferably to be open to at least one other hollow chamber (7, 8; 5, 6) in each case.

5. The crash box according to any one of the preceding claims, characterized in that The at least one outer hollow chamber (5, 6) has a longitudinal axis (18) in the front section (10), which forms an angle α of less than 40° with respect to the longitudinal axis (19) of the at least one inner hollow chamber (7, 8), wherein the angle α is preferably designed to be greater than 3°.

6. The crash box according to any one of the preceding claims, characterized in that In the front section (10), the at least one outer hollow chamber (5, 6) and the at least one inner hollow chamber (7, 8) have a spacing which increases continuously towards the bumper-side end (3).

7. The crash box according to any one of the preceding claims, characterized in that The front section (10) extends over 1 / 5 to 2 / 3 of the total length of the crash box (1).

8. The crash box according to any one of the preceding claims, characterized in that In the front section (10), the at least one outer hollow chamber (5, 6) is separated from the at least one inner hollow chamber (7, 8) by a gap (11), which is preferably rounded towards the end section (9), in particular rounded by a radius (17), wherein the radius (17) corresponds at least to the wall thickness of the hollow chamber (5, 6, 7, 8) in the end section (9).

9. The crash box according to any one of the preceding claims, characterized in that In the front section (10), a bridge (15', 16') is arranged on the hollow chamber (5, 6, 7, 8), a bead is arranged in the bridge as a deformation element, wherein the bead preferably extends into the partition wall (12, 13) and the upper and / or lower limiting wall (30, 31) of the hollow chamber (5, 6, 7, 8).

10. The crash box according to claim 1, characterized in that The hollow chambers (5, 6, 7, 8) each have a constant width of at least 20 mm over their entire longitudinal extension from the vehicle-side end (4) to the bumper-side end (3).

11. A bumper assembly (2) for a motor vehicle, comprising two crash boxes (1) according to any one of the preceding claims and at least one cross member (20), the two crash boxes (1) being connected to one another via the at least one cross member.

12. The bumper assembly (2) according to claim 11, characterized in that: a) the at least one outer hollow chamber (5, 6) is arranged closer to the end of the at least one crossbeam (20) than the at least one inner hollow chamber (7, 8), or b) The at least one outer hollow chamber (5, 6) of the crash box (1) is arranged above the at least one inner hollow chamber (7, 8).

13. The bumper assembly (2) according to claim 11, characterized in that: The height of the at least one cross beam (20) is greater than the cross-sectional height of the vehicle end section of the crash box (1), wherein at least one outer hollow chamber (5, 6) of the crash box (1) is arranged above the at least one inner hollow chamber (7, 8) and supported on an upper fastening area of ​​the at least one cross beam (20), while the at least one inner hollow chamber (7, 8) is supported on a lower fastening area of ​​the at least one cross beam (20).

14. The bumper assembly according to claim 11, characterized in that: The crash box (1) is joined, preferably screwed or integrally joined, in particular welded, to the at least one cross member (20).

15. A method for producing a bumper assembly according to any one of claims 11 to 14, the bumper assembly having two crash boxes (1) according to any one of claims 1 to 10, the method comprising the following method steps: a) providing two multi-chamber hollow profiles (21) having at least one outer hollow chamber (5, 6) and at least one inner hollow chamber (7, 8), b) introducing a slot (11) into the front section (10) of the multi-chamber hollow profile (30) for separating and spacing the at least one outer hollow chamber (5, 6) from the at least one inner hollow chamber (7, 8) and for producing two crash boxes, c) providing two crash boxes ( 1 ) according to any one of claims 1 to 10, d) Joining the two crash boxes (1) to at least one cross member (20).

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