Bumper Cross Beam For A Motor Vehicle

Abstract

A bumper crossmember for a motor vehicle having a crossmember extending transversely to the longitudinal axis of the vehicle and two crashboxes connected thereto. Each crashbox is connected with its end facing away from the vehicle to the crossmember in a respective end section thereof, and with its end facing the vehicle is connectable to a structural component of the vehicle, e.g., a longitudinal member. The crossmember has a corrugated structure in the area where a crashbox is connected. A tow sleeve is integrated into the bumper crossmember in the connection area of the crashbox. The tow sleeve is held in a vertex structure of the corrugated structure in a form-fitting manner in the z and y directions, the vertex area of this vertex structure facing away from the crashbox, with the lateral surface of the tow sleeve on the flanks facing one another and forming the vertex structure.

Claims

1-11. (canceled)

12. A bumper crossmember for a motor vehicle, wherein an x-direction corresponds to a longitudinal extension of the vehicle, a y-direction corresponds to a transverse extension of the vehicle, and a z-direction corresponds to a vertical direction, the bumper crossmember comprising: a crossmember having a longitudinal extension extending in the y-direction and two crashboxes connected thereto in respective end sections of the crossmember, the crashboxes each having a first end connected to the crossmember and an opposite second end configured to be connected to a structural component of the vehicle, wherein the crossmember has a corrugated structure in a connection area of at least one of the crashboxes, and a tow sleeve integrated in the bumper crossmember in the connection area of the crashbox, wherein the tow sleeve is held in the corrugated structure in a form-fitting manner in the z-direction and in the y-direction in a vertex structure of the corrugated structure, the vertex structure having a vertex area pointing away from the crashbox, with a lateral surface of the tow sleeve on flanks of the corrugated structure facing one another and forming the vertex structure.

13. The bumper crossmember of claim 12, wherein the vertex structure has a vertex surface which is widened in the z-direction in an area around the tow sleeve.

14. The bumper crossmember of claim 12, wherein vertex areas of vertex structures adjacent to the vertex structure carrying the tow sleeve are unaffected by accommodation of the tow sleeve.

15. The bumper crossmember of claim 12, wherein the flanks forming the vertex structure carrying the tow sleeve are inclined toward one another relative to a horizontal in a direction pointing away from the crashbox.

16. The bumper crossmember of claim 12, wherein the tow sleeve has a collar with a conical lateral surface as flank contact for the flanks.

17. The bumper crossmember of claim 16, wherein a tow sleeve aperture is formed in the vertex structure of the crossmember for the tow sleeve to pass through, and wall sections of the vertex structure forming the tow sleeve aperture abut against an outer surface of the tow sleeve.

18. The bumper crossmember of claim 17, wherein abutment of the tow sleeve aperture against the outer surface of the tow sleeve is provided at a distance in the x-direction from the collar.

19. The bumper crossmember of claim 12, wherein a tow sleeve aperture is formed in the vertex structure of the crossmember for the tow sleeve to pass through, and wall sections of the vertex structure forming the aperture abut against an outer surface of the tow sleeve.

20. The bumper crossmember of claim 12, wherein the corrugated structure of the crossmember is aligned in the z-direction, and the corrugated structure comprises at least three vertex structures following the longitudinal extension of the crossmember, wherein two vertex structures adjacent in the z-direction are connected to one another by a flank inclined relative to a horizontal, and upper and lower end-face areas of the crashbox are supported on flanks of the corrugated structure.

21. The bumper crossmember of claim 20 wherein the upper end-face area is supported on an upper flank which faces upward in the z-direction and the lower end-face area is supported on a lower flank which faces downward in the z-direction.

22. The bumper crossmember of claim 21, wherein the first end of the crashbox has a support lug which projects toward a rear side of the crossmember and which is only supported on the flanks facing one another and forming the vertex structure carrying the tow sleeve, each of said flanks connecting the vertex structure carrying the tow sleeve to an adjacent vertex structure of the corrugated structure.

23. The bumper crossmember of claim 22, wherein the crashbox is connected by joining to the crossmember only along its support on the crossmember.

24. The bumper crossmember of claim 21, wherein the crashbox is connected by joining to the crossmember only along its support on the crossmember.

25. The bumper crossmember of claim 20, wherein the crashbox is connected by joining to the crossmember only along its support on the crossmember.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The following description is provided on the basis of an example embodiment with reference to the accompanying drawings, wherein:

[0021] FIG. 1 shows a perspective view of a bumper crossmember,

[0022] FIG. 2 shows a cross-sectional view through the bumper crossmember of FIG. 1 with a line of intersection at the center of its longitudinal extension, as viewed in the direction toward the left end shown in FIG. 1,

[0023] FIGS. 3a and 3b show a front side view of the bumper crossmember of FIG. 1 (FIG. 3a) and an enlarged view of its left end section (FIG. 3b), and

[0024] FIG. 4 shows a sectional view through the bumper crossmember along line A-A of FIG. 3a.

DETAILED DESCRIPTION

[0025] With reference to FIG. 1, a bumper crossmember 1 comprises a crossmember 2 to which a crashbox 3, 3.1 is connected in the area of either end. The crossmember 2 of the bumper crossmember 1 has a corrugated structure aligned in the z-direction. The profiling of the corrugated structure extends with its vertex structures in the longitudinal direction of the crossmember 2. The crossmember 2 is a press-formed steel component.

[0026] Crashbox 3—crashbox 3.1 is of identical design—is composed of two U-shaped half shells 4, 4.1, each press-formed from a steel blank. The two half shells 4, 4.1 adjoin each other with their longitudinal joints and are welded together at this point. At the end facing a vehicle not shown in the figures, the crashbox 3 carries a so-called baseplate 5, with which the bumper crossmember 1 is connected to a vehicle side member in the embodiment shown.

[0027] Due to the profiling of the crossmember 2 in the vertical direction, as shown in FIG. 1, the end face of the crashbox 3 facing the rear of the crossmember 2 is also profiled accordingly, as can be seen in FIG. 2.

[0028] As is seen more clearly in FIG. 2, the corrugated structure of the crossmember 2 has three positive vertex structures 6, 6.1, 6.2 facing away from the vehicle, as well as two intermediate negative vertex structures 7, 7.1 in the form of recesses opposite the positive vertex structures 6, 6.1, 6.2. In the direction toward the crashbox 3, the negative vertex structures 7, 7.1 represent the positive vertex structures, and the vertex structures 6, 6.1, 6.2 represent the negative vertex structures, in that these recede with in relation to the vertex structures 7, 7.1. Adjacent vertex structures are connected to one another by means of a flank 8, 8.1, 8.2, 8.3, respectively. These flanks 8, 8.1, 8.2, 8.3 are inclined relative to the horizontal at about 30 degrees in the embodiment shown.

[0029] The contouring of the end face of the crashbox 3 facing the crossmember 2 is designed, such that the upper end-face area 10 provided by the upper wall 9 and the lower end-face area 12 provided by the lower wall 11 are each supported over their extension in the y direction on a flank 8, 8.3 facing in the vertical direction and joined to the latter by a welded joint. The area of support of the upper and lower end-face areas 10, 12 on the flank 8 and 8.3, respectively, is indicated in FIG. 2 by a block arrow. In contrast, the vertex structure 7, 7.1 facing the crashbox 3 is not supported on the complementary contour 13, 13.1 in the end-face design of the crashbox 3.

[0030] The two side walls 14 of the crashbox 3, of which only the side wall 14 is visible in FIG. 1, carry a support lug 15 projecting in the direction of the longitudinal extension of the crashbox 3 in the direction of the crossmember 2. This support lug 15 engages in the negative vertex structure 6.1 located between the vertex structures 7, 7.1 when viewed from the direction of the crashbox 3. With regard to its outline geometry, which is visible in FIG. 2, the support bracket 15 is designed such that it is supported only on the inclined flanks 8.1, 8.2 facing one another. Each of these support areas are also indicated by a block arrow. The vertex of the support lug 15 facing the crossmember 2 is in turn spaced apart from the vertex structure 6.1.

[0031] In the case of impact energy absorption, as indicated by the block arrow in FIG. 2, the impact energy is initially introduced in the crashbox 3 only in the end-face areas located on the flanks 8, 8.1, 8.2, 8.3. Only when the end-face areas supported directly on the rear of the crossmember 2 have begun to deform, i.e., are deformed in the direction of the base plate 5, do the vertex structures 6.1, 7, 7.1 come into contact with the complementary geometries 13, 13.1, as well as the vertex of the support bracket 15, with their sides facing the crashbox 3. Only then, the crashbox 3 becomes deformed over its whole cross-sectional area facing the crossmember 2 for further energy absorption.

[0032] The design of the crashbox 3 support shown in FIG. 2 with its end facing away from the vehicle at the rear of the crossmember 2 indicates that the distance between the vertex structures 7, 7.1 to the complementary geometries 13, 13.1 of the crashbox 3 is less than the distance of the vertex of the support lug 15 to the vertex structure 6.1. Thus, an initial application of force until an application of force over the whole cross-sectional area of the crashbox is devised in three stages from the crossmember 2 to the crashbox. While at the beginning of a first deformation phase, energy is only applied to the crashbox 3 via the upper and lower end-face areas 10, 12, after the first deformation phase of the crashbox 3, the vertices 7, 7.1 come into contact against the complementary geometries 13, 13.1 of the crashbox 3, such that these support areas are also included in the further deformation. Only after further deformation does the side of the vertex structure 6.1 facing the crashbox 3 come into contact with the vertex of the support bracket 15. Subsequently, a force is applied to the crashbox 3 over its whole cross-sectional geometry.

[0033] The above-described design of the bumper crossmember 1 results in a substantially reduced initial peak, if the deformation behavior described above is plotted in a force-displacement diagram.

[0034] A tow sleeve 16 is integrated into the bumper crossmember 1 in its left end section. The tow sleeve 16 protrudes slightly from the front of the crossmember 2 and thus from its side facing away from the vehicle. The purpose of the tow sleeve 16 is to fasten a tow hook or tow eye therein, such that the vehicle to which the bumper crossmember 1 is connected may be towed, if necessary.

[0035] The tow sleeve 16 is located within the connection area of the crashbox 3 to the crossmember 2, as shown in the front views of FIGS. 3a and 3b. The tow sleeve 16 is located in the center of the end face enclosed by the walls 9, 11, 14 of the crashbox 3. The tow sleeve 16 is integrated in the corrugated structure of the crossmember 2, specifically in the vertex structure 6.1 with its vertex or vertex area facing away from the crashbox 3. The vertex structure 6.1 has a vertex surface 17, which is widened in the vertical direction (z-direction) in the area around the tow sleeve 16. In the example embodiment shown, the vertex surface 16 is designed to be non-curved. Thus, this vertex surface 17 differs from the otherwise curved vertex area of vertex structure 6.1. A tow sleeve aperture 18 is introduced into the widened vertex surface 17 of the vertex structure 6.1. Due to the widening of the vertex surface 17 of the vertex structure 6.1 in the area of the edging of the tow sleeve 16, and since the vertex areas of the adjacent vertex structures 7, 7.1 are unaffected by the widening of the vertex surface 17, the flank formation differs from that of the adjacent sections. The flanks 8.1, 8.2 forming the vertex structure 6.1 are adapted to the diameter of the tow sleeve aperture 18, such that their wall sections facing one another enclose the lateral surface of the tow sleeve 16 in its upper and lower vertex areas (see in particular FIG. 3b). In the illustrated embodiment, the tow sleeve 16 is bordered externally by the relevant flank sections of the flanks 8.1, 8.2 over approximately 50 degrees, wherein the upper and lower vertex lines of the tow sleeve 16 are preferably located centrally in this border section.

[0036] As can be seen in FIG. 4, the tow sleeve 16 is basically a cylindrical component with a front insertion opening 19 and a rear section with an internal thread 20. The thread of a tow eye or tow hook is fastened to the internal thread 20. The tow sleeve 16 carries a collar 21 projecting from its cylindrical outer surface, wherein the outer surface of said collar 21 is inclined conically in the direction of the tow sleeve aperture 18 in accordance with the inclination of the flank sections of the flanks 8.1, 8.2 enclosing the tow sleeve 16. As can be seen in FIG. 4, it has a longitudinally axial, straight extension (x direction), and thus bears at least substantially along the full height of these curved flank sections of the flanks 8.1, 8.2 against the lateral surface of the collar 21 of the tow sleeve 16.

[0037] The tow sleeve aperture 18 is introduced into the vertex surface 17 of the vertex structure 6.1. As a result, the curved sections to the flanks 8.1, 8.2 remain and thus the wall sections of the vertex structure 6.1 enclosing the tow sleeve aperture 18 abut against the front cylindrical portion of the tow sleeve 16. The tow sleeve 16 is thus supported in the vertex structure 6.1 via a two-point support, wherein the rear support in the direction of the crashbox 3 is the above-described flat support. The hole edge area of the tow sleeve aperture 18 is located at a certain distance in the x direction from the collar 21.

[0038] Enclosing the tow sleeve 16 on the lateral surface of its collar 21 in its upper and lower vertex areas provides effective two-point support for the tow eye 16 circumferentially in the transverse direction, which is the reason for the particular transverse force loading of this section sleeve 16.

[0039] Due to the conical support of the tow sleeve 16 with its conical lateral surface of the collar 21 on the inner sides of the flanks 8.1, 8.2, the tow eye 16 can be inserted in this vertex structure 6.1 from the side of the crossmember 2 facing the vehicle and is initially frictionally held therein. Instead of a frictional connection, the tow sleeve 16 may also be bonded with the lateral surface of its collar 21 to the inner sides of the flanks 8.1, 8.2. This facilitates assembly of the tow sleeve 16 in or on the crossmember 2, during which assembly, the tow sleeve 16 is welded to the vertex surface 17 of the vertex structure 6.1, typically in a circumferential fashion. This is done in the circumferential groove between the section of the tow sleeve 16 projecting from the vertex structure 6.1 and the outside of the vertex surface 17.

[0040] The corrugated structure is stiffened in the connection area of the crashbox 3 by connecting the latter thereto. This applies in particular to the vertex structure 6.1. Due to the connection of the crashbox 3 with its upper end area 10 to the flank 8, and with its lower end area 12 to the flank 8.3, and due to the engagement of the support lug 15 in the mutually facing flanks 8.1, 8.2 of the vertex structure 6.1 carrying the tow sleeve 16, transverse forces acting in the vertical direction (z-direction) on a tow eye inserted in the tow sleeve 16 may also be absorbed without deformation.

REFERENCE NUMERAL LIST

[0041] 1 Bumper crossmember [0042] 2 Crossmember [0043] 3, 3.1 Crashbox [0044] 4, 4.1 Half shell [0045] 5. Baseplate [0046] 6, 6.1, 6.2 Vertex structure [0047] 7, 7.1 Vertex structure [0048] 8, 8.1-8.3 Flank [0049] 9 Wall [0050] 10 upper face [0051] 11 Wall [0052] 12 lower front [0053] 13, 13.1 Complementary contour [0054] 14 Side wall [0055] 15 Support lug [0056] 16 Tow sleeve [0057] 17 Vertex area [0058] 18 Tow sleeve aperture [0059] 19 Insertion opening [0060] 20 Internal thread [0061] 21 Collar