Bumper system for a motor vehicle

Abstract

A bumper system for a motor vehicle, comprising at least one crash box (1) arranged on a bumper cross member (3) by means of a bracket (2), the bracket (2) being provided with a first bracket plate (4) and a second bracket plate (5), the first bracket plate (4) at least partially abutting a first limiting element (8) and the second bracket plate (5) abutting a second limiting element (9) of the bumper cross member (3), characterized in that the bumper cross member (3) is received in the bracket (2) such that the first bracket plate (4) and / or the second bracket plate (5) extend in the direction of the vehicle's longitudinal axis (7) over at least ¾ of the bumper cross member (3) in the direction of a bumper cross member front wall (10), the first bracket plate (4) being designed as an upper bracket plate and the second bracket plate (5) as a lower bracket plate.which are connected to each other via a rear console plate (6), wherein the console (2) is integrally connected to the crash box (1) as a separate component.

Description

[0001] The invention relates to a bumper system for a motor vehicle according to the preamble of patent claim 1.

[0002] A generic bumper system is known, for example, from DE 10 2004 013 713 A1 and DE 10 2004 056 249 A1. In both publications, a C-shaped bracket, which is welded to the crash box, is arranged on a bumper cross member. The C-shaped bracket profiles of these bumper systems are arranged with an upper bracket plate and a lower bracket plate in the rear, vehicle-center-facing area of ​​an upper and a lower boundary wall of the bumper cross member. The bracket is attached to the bumper cross member by means of a detachable screw connection. Using these screw connections, the bumper cross member can be detached from the bracket, which is particularly advantageous if the bumper cross member needs to be replaced as a result of a motor vehicle accident.

[0003] Such bumper systems for motor vehicles exhibit a specific deformation behavior in the event of an accident. Back in the 1980s, the Allianz Center for Technology (AZT) developed a crash repair test with the goal of reducing vehicle damage in rear-end collisions. To this day, this test forms the basis for insurance companies' vehicle type classifications. Vehicle manufacturers consider it when developing new vehicle models, and car owners benefit from it through reduced vehicle damage in the event of a traffic accident. The AZT crash repair test laid the foundation for ensuring good deformation behavior. It was introduced into an international network of research institutes in 1999 and adopted there as an international standard. It has been further developed under the name RCAR (Research Council for Automobile Repairs) test.

[0004] However, in the two publications mentioned above, the connection of the bracket to the bumper cross member does not allow for a sufficiently predictable high force level in the AZT load case with a correspondingly defined introduction of energy into the bumper system. This becomes particularly difficult when an aluminum profile is used as the bumper cross member, which is relatively soft and deforms uncontrollably in the first few millimeters of deformation during the load case, resulting in no or only insufficiently predictable energy introduction and minimal intrusion into the bumper system.

[0005] DE 195 45 069 A1 discloses a bumper system for motor vehicles, which has a bumper with a cross member in a half-shell design and crash boxes.

[0006] DE 196 11 934 C1 and US 6 318 775 B1 also classify such bumper systems for motor vehicles as state of the art.

[0007] The object of the invention is therefore to further develop a bumper system for motor vehicles of the type mentioned above in such a way that a defined high force level can be transferred to the body in a controlled manner during the AZT load case, thereby minimizing consequential damage to the vehicle. This would not only make it possible to keep costs low for the car owner or the car insurer, but would also result in a resource-efficient bumper system, as spare parts could be saved.

[0008] This object is achieved by a bumper system having all the features of patent claim 1. Advantageous embodiments of the invention can be found in the subclaims.

[0009] The bumper system according to the invention for a motor vehicle comprises at least one crash box, which is arranged on a bumper cross member by means of a bracket. The bracket is provided with a first bracket plate and a second bracket plate, with the first bracket plate at least partially abutting a first limiting element and the second bracket plate abutting a second limiting element of the bumper cross member.According to the invention, the bumper cross member is now received in the console in such a way that the first console plate and / or the second console plate extends in the direction of the vehicle's longitudinal axis over at least ¾ of the bumper cross member in the direction of a bumper cross member front wall, wherein the first console plate is designed as an upper console plate and the second console plate as a lower console plate, which are connected to one another via a rear console plate, wherein the console is integrally connected to the crash box as a separate component.

[0010] Thanks to this design of the bumper system for motor vehicles according to the invention, deformation energy is now introduced directly and in a very targeted and predictable manner into the console in the area of ​​the crash boxes when a load is applied, as this extends as far as the front wall of the bumper cross member. When a load is applied, the bumper cross member is then unable to deform in the area where it is connected to the console without energy being introduced directly into the console and thus into the crash box, the bumper system, and the body. Because the energy is thus introduced directly into the crash box, the energy can be intercepted in a very targeted manner and introduced into the crash box when a load is applied, minimizing damage to the area outside the crash box, the console, and the bumper cross member. This increases the force level, resulting in greater energy dissipation and absorption in the bumper cross member.This minimizes the subsequent costs for the car owner or the car insurer in the event of an accident, as the invention also significantly reduces damage outside the bumper system. Furthermore, this results in a resource-efficient bumper system, as in the event of an accident involving motor vehicles with the bumper system according to the invention, significantly fewer parts outside the bumper system need to be replaced, as these are significantly less damaged due to the highly targeted energy and deformation input into the bumper system than with prior art bumper systems.

[0011] According to the invention, the first console plate is designed as an upper console plate and the second console plate is designed as a lower console plate, which are connected or joined to one another via a rear console plate.

[0012] According to a first advantageous embodiment of the invention, the front wall of the bumper cross member is provided with a flange which extends, at least in the region of the at least one crash box, in the direction of the vehicle's vertical axis with an upper end pointing upwards and / or a lower end pointing downwards beyond the rest of the bumper cross member. This embodiment of the invention also further increases the targeted energy input into the crash box in the event of an accident or a load case. This flange ensures that the bumper cross member introduces its deformation into the console and thus into the crash box right at the start of a load case, thus further reducing damage to vehicle components outside the bumper system.

[0013] It has also proven advantageous that the flange of the bumper cross member front wall is shaped such that its upper and / or lower ends, which extend beyond the rest of the bumper cross member in the direction of the vehicle's vertical axis, are deformed toward the vehicle's center in the direction of the vehicle's longitudinal axis. This special shape of the flange, with its ends projecting beyond the bumper cross member, provides additional positive locking or interlocking of these ends, and thus of the flange, with the upper and / or lower console plate in the event of a crash. This also allows for particularly effective and targeted dissipation of deformation energy. This in turn reduces follow-up costs for repairs and thus also saves resources in the form of spare parts.

[0014] In order to further improve the dissipation of the energy introduced into the crash box, the upper end of the flange can nestle against the upper console plate and / or the lower end of the flange can nestle against the lower console plate, in particular nestle against it over its entire surface.

[0015] The bumper system according to the invention for a motor vehicle is particularly advantageous when the bumper cross member is designed as an aluminum profile, in particular as a single-chamber aluminum profile or multi-chamber aluminum profile and optionally with additional three-dimensional deformations and / or curvatures. By designing the bumper cross member as an aluminum profile, a particularly lightweight bumper system is provided, which, however, results in very rapid deformation of the bumper cross member under load due to the physical properties of aluminum. Due to the special connection of the console to the bumper cross member, the invention now achieves, when using aluminum profiles as bumper cross members, that despite weight savings, a very targeted and predictable dissipation of energy into the bumper system, in particular the crash box, is enabled in the event of a crash.The use of aluminum also allows for weight savings and thus a significant reduction in the operating costs of the vehicle, without having to forego a defined and predictable dissipation of energy into the bumper system or the crash box in the event of an accident.

[0016] To further increase the stability of the bumper cross member, it has proven advantageous to provide the bumper cross member with at least one preferably continuous bead or longitudinal groove along its longitudinal extension, transverse to the vehicle's longitudinal axis, in the front and / or rear walls of the bumper cross member. Such beads or longitudinal grooves significantly increase the stability of a hollow profile of the bumper cross member without the use of additional material. This also allows for resource savings in the event of a crash and makes the operation of the vehicle more resource-efficient.

[0017] The design of the invention also aims in the same direction, in which the crash box is provided with longitudinal ribs along the vehicle's longitudinal axis. This also further increases the stability and force level, or rather, the energy dissipation, of the entire bumper system. Waves and transverse ribs parallel to the vehicle's vertical and transverse axes allow the energy dissipation and deformation progression to be controlled even more precisely in the bumper system or crash box under load.

[0018] Advantageously, the crash box consists of at least one sheet steel shell, preferably a left-hand steel shell and a right-hand steel shell, preferably integrally connected by welding. The cross-section of the crash box is polygonal, particularly rectangular, with rounded corners transverse to the vehicle's longitudinal axis. This embodiment of the invention also serves to increase the stability of the bumper system, with damage to other elements of the motor vehicle being further minimized in the event of a load, particularly due to the rounded corners of the polygonal cross-section of the crash box.

[0019] Advantageously, the bracket, formed from sheet steel, is connected to the crash box by welding, with the bracket being provided with a zinc coating at least in the connection area to the bumper cross member. The zinc coating serves primarily as corrosion protection, as the bumper cross member to which the bracket is connected is made of aluminum. Due to the physical and chemical properties of aluminum and steel, direct contact between the two could otherwise result in corrosion of the steel, which would lead to a non-functional bumper system. The zinc coating can also be used for brazing the bracket and bumper cross member if a reversible connection is not desired or necessary.

[0020] The bracket is connected to the bumper cross member in a force-fitting but detachable manner, particularly by screwing. Such a detachable connection, such as a screw connection (to which the invention is not intended to be limited), makes it possible, in the event of an accident, to replace a damaged bumper cross member without having to replace the rest of the bumper system, provided it is still functional.

[0021] Furthermore, it can be provided that the rear console plate is provided with a through-opening, in particular for passing through a towing device or a towing eye.

[0022] Further objects, features and possible applications of the present invention will become apparent from the following description of an embodiment with reference to the drawing.

[0023] They show: Fig. 1 to 10: various representations of bumper systems according to the invention for a motor vehicle, Fig. 11a: partial representation of a further embodiment of the invention as an aluminum bumper system in a longitudinal section, Fig. 11b: the aluminum bumper system of the Fig. 11a in a plan view, Fig. 12: an embodiment of the console 2 of a bumper system according to the invention and

[0024] In the Fig. 9 and Fig. Figure 10 shows an embodiment of a bumper system according to the invention for a motor vehicle as a wireframe model. The bumper system there comprises a bumper cross member 3 configured as a multi-chamber profile. The bumper cross member 3 has an upper limiting element 8, a lower limiting element 9, a bumper cross member front wall 10, and a bumper cross member rear wall 17.

[0025] The bumper cross member 3 is essentially rectangular in shape and bent or curved along its longitudinal extent. Within the bumper cross member 3, which is designed as a multi-chamber profile, a corrugated partition wall 19 is arranged, connecting the bumper cross member front wall 10 to the bumper cross member rear wall 17. The partition wall 19 is arranged in the center of the bumper cross member 3.

[0026] The bumper cross member front wall 10 has two continuous beads 18 along its entire longitudinal extent, which increase the stability of the bumper cross member 3. The present bumper cross member 3 is designed as a hollow aluminum profile, at each end of which a crash box 1 is arranged via a bracket 2. Both the brackets 2 and the crash boxes 1 are made of sheet steel.

[0027] While the console 2 is integrally connected to the crash boxes 1 by welding, the consoles 2 are firmly but detachably bolted to the bumper cross member 3 at fastening points 15. Such screw connections allow damaged bumper cross members 3 to be easily removed from the bumper system after an accident and replaced with a new bumper cross member 3. Visible here is a screw connection at four fastening points 15 of the rear console plate 6.

[0028] In the Fig. 7 and Fig. 8 is a bumper system according to the invention according to the Fig. 9 and Fig. 10 in a side view, where in Fig. 7 the bumper cross member 3 is a single-chamber hollow profile without intermediate wall 19 and in Fig. 8 the bumper cross member 3 is shown as a multi-chamber hollow profile with intermediate wall 19. It is clearly visible in the Fig. 7 and Fig. 8, such as the console 2 with a first console plate 4, which is designed as an upper console plate, is arranged on an upper, corrugated boundary element 8 of the bumper cross member 3, while a second console plate 5, which is designed as a lower console plate, is arranged on a lower, corrugated boundary element 9 of the bumper cross member 3. The upper console plate 4 rests partially on the upper boundary element 8 and the lower console plate 5 rests partially on the lower boundary element 9.

[0029] The lower console plate 5 is connected to the upper console plate 4 via a rear console plate 6 and is formed in one piece, wherein the rear console plate 6 lies flat against a bumper cross member rear wall 17 and the console 2 is detachably arranged there by means of screw connections at the fastening points 15 on the bumper cross member 3.

[0030] Both the upper console plate 4 and the lower console plate 5 extend from the bumper cross member rear wall 17 to the bumper cross member front wall 10. The bumper cross member front wall 10 is formed with a flange 11 which extends in the direction of the vehicle vertical axis 12 beyond the remaining bumper cross member 3 with a lower end 14 and an upper end 13.

[0031] The cross-section and / or a depth T1 of the bumper cross member 3 is designed to be reduced in the area of ​​its connection to the console 2 or the crash box 1 compared to its remaining cross-section or its remaining depth T. This provides better energy dissipation and reproducible deformation behavior in the event of a crash.

[0032] As in particular the Fig. 7 and Fig. 8 and also the Fig. 1 to 6, the upper end 13 and the lower end 14 of the flange 11 in the area where the bumper cross member 3 is connected to the bracket 2 or the crash box 1 are shaped in the direction of the vehicle's longitudinal axis 7 towards the vehicle center. This ensures that the upper bracket plate 4 and the lower bracket plate 5 immediately come into contact with the flange 11 in the area of ​​its upper end 13 and its lower end 14 in the event of an accident, so that a very targeted and rapid introduction of energy into the crash box 1 or the bumper system and the body takes place and the lower bracket plate 5 and the upper bracket plate 4 are supported on the repositioned flange 11 and hook into it. This also prevents the bumper cross member 3 from sliding relative to the bracket 2.

[0033] In the exemplary embodiments shown in the figures, the crash box 1 has a transverse bead 16 in the area of ​​its upper boundary wall. This transverse bead 16 also serves to increase the stability of the entire bumper system.

[0034] The Fig. 1 to 6 show detailed views of an embodiment of a bumper system according to the invention, wherein the console 2 is welded to the crash box 1 and the bumper cross member 3 is detachably connected to the console 2 by means of screw connections at the fastening points 15.

[0035] In Fig. 1 and Fig. 4 also shows a side console plate 21 which is joined to the upper console plate 4 and the lower console plate 5 by a weld.

[0036] Furthermore, especially in the Fig. 2 and Fig. 3 also shows a further transverse bead 20 on the inner wall of the crash box 1, which serves to control deformation during a crash.

[0037] Also the Fig. 1 to 6, it can be clearly seen that the upper end 13 and the lower end 14 of the flange 11 are curved or bent toward the center of the vehicle only in the area where the bumper cross member 3 is connected to the bracket 2. This provides additional positive locking or interlocking in the event of a crash, which also relieves the load on the connection to the crash box 1. Furthermore, such a design of the upper end 13 and the lower end 14 of the flange further increases the stability of the bumper cross member 3 and thus of the entire bumper system and enables a more targeted introduction of energy into the bumper system in the event of a crash.

[0038] In the Fig. 1 to 6 it is also clearly visible that the crash box 1 is made of two sheet steel shells which are joined by welding.

[0039] The Fig. 11 a and Fig. 11b show a further embodiment of the invention as an aluminum bumper system in a longitudinal section ( Fig. 11a) and in a top view Fig. 11b). A bumper cross member 3 with two hollow chambers formed in its longitudinal direction is encompassed at the rear by a bracket 2, with an upper bracket plate 4 of the bracket 2 spanning an upper limiting element 8 of the bumper cross member, and a lower bracket plate 5 spanning a lower limiting element 9 of the bumper cross member 3, and contacting them in sections. Both the upper and lower limiting elements 8 and 9, as well as an intermediate wall 19, have a longitudinal groove only in the connection area to the crash box 1. The bracket 2 is materially coupled to a crash box 1 made of aluminum, designed as a multi-chamber profile, and has a partition wall and two hollow chambers in longitudinal section. The crash box 1 itself is arranged in sections in a longitudinal member of the vehicle body and can be secured thereto via screw bolts. These are indicated in Fig. 11b.

[0040] Fig.Figure 12 shows an embodiment of the console 2 with an upper console plate 4, a lower console plate 5, a side console plate 21, and a rear console plate 6, the latter having passages for screwing to a rear wall of the bumper cross member. The adjacent side, upper, and lower console walls are connected to each other by weld seams 22. List of reference symbols 1 crash box 2 consoles 3 bumper cross members 4 first console plate 5 second console plate 6 rear console plate 7 Vehicle longitudinal axis 8 Boundary element 9 Boundary element 10 bumper cross member front wall 11 Flange 12 Vehicle vertical axis 13 upper end 14 lower end 15 attachment points 16 cross beads 17 Bumper cross member rear wall 18 bead 19 Partition wall 20 cross beads 21 side console plate 22 Weld seam T Depth T1 depth

Claims

[1] Bumper system for a motor vehicle with at least one crash box (1) which is arranged on a bumper cross member (3) by means of a bracket (2), wherein the bracket (2) is provided with a first bracket plate (4) and a second bracket plate (5), wherein the first bracket plate (4) at least partially rests on a first limiting element (8) and the second bracket plate (5) on a second limiting element (9) of the bumper cross member (3), characterized byin that the bumper cross member (3) is received in the console (2) in such a way that the first console plate (4) and / or the second console plate (5) extends in the direction of the vehicle's longitudinal axis (7) over at least ¾ of the bumper cross member (3) in the direction of a bumper cross member front wall (10), wherein the first console plate (4) is designed as an upper console plate and the second console plate (5) is designed as a lower console plate, which are connected to one another via a rear console plate (6), wherein the console (2) is connected to the crash box (1) as a separate component in a materially bonded manner. [2] Bumper system according to claim 1, characterized bythat the bumper cross member front wall (10) is provided with a flange (11) which extends at least in the region of the at least one crash box (1) in the direction of the vehicle vertical axis (12) with an upper end (13) upwards and / or with a lower end (14) downwards beyond the remaining bumper cross member (3). [3] Bumper system according to claim 2, characterized by that the flange (11) of the bumper cross member front wall (10) is shaped at least in the region of the crash box (1) in such a way that it is shaped with its upper end (13) and / or lower end (14) extending beyond the remaining bumper cross member (3) in the direction of the vehicle's vertical axis (12) towards a passenger compartment, opposite to the direction of the vehicle's longitudinal axis (7). [4] Bumper system according to one of the preceding claims, characterized by that the bumper cross member (3) is designed as an aluminum profile. [5] Bumper system according to claim 4, characterized by that the bumper cross member (3) is designed as a single-chamber aluminum profile or multi-chamber aluminum profile. [6] Bumper system according to claim 4 or 5, characterized by that the bumper cross member (3) is designed with additional three-dimensional deformations and / or curvatures. [7] Bumper system according to one of the preceding claims, characterized by that the bumper cross member (3) is provided with at least one bead or longitudinal groove over its longitudinal extent transversely to the vehicle's longitudinal axis (7). [8] Bumper system according to one of the preceding claims, characterized by that the crash box (1) consists of at least one sheet steel shell, wherein the cross section of the crash box (1) transverse to the vehicle longitudinal axis (7) is polygonal with rounded corners. [9] Bumper system according to one of the preceding claims, characterized bythat the console (2) is formed from a steel sheet and is connected to the crash box (1) by welding, wherein the console (2) is provided with a zinc coating at least in a connection area to the bumper cross member (3). [10] Bumper system according to one of the preceding claims, characterized by that the console (2) is firmly connected to the bumper cross member (3) by screwing. [11] Bumper system according to one of claims 2 to 10, characterized by that the rear console plate (6) is provided with a through-opening for the passage of a towing device or a towing eye.

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