INTERNAL FRAME TUBE TRANSVERSE ELEMENT

Abstract

A structural support assembly for a vehicle, comprising a longitudinal frame element extending parallel to a longitudinal centerline of the vehicle and having an inner rail wall and an outer rail wall, a cross member operatively coupled to the longitudinal frame element and extending substantially perpendicular to the longitudinal centerline, and an internal frame reinforcement element operatively coupled only to the inner rail wall of the longitudinal frame element. The internal frame reinforcement element may be located near an intersection of the cross member and the longitudinal frame element.

Description

AREA OF TECHNOLOGY

[0001] Exemplary embodiments generally relate to a vehicle frame architecture and, in particular, a tubular cross-section element that may be provided within a frame element to improve performance in response to a frontal and offset barrier event. GENERAL STATE OF THE ART

[0002] In a typical frontal barrier event, adding a welded internal structure to the frame encloses deformable retraction space required for momentum management, thereby reducing power and increasing momentum. On the other hand, internal frame reinforcements are helpful in supporting a robust lateral load path for offset barrier events. Thus, a certain balance between these competing interests may be desirable. BRIEF SUMMARY OF SOME EXAMPLES

[0003] According to one embodiment, a structural support assembly can be provided for a vehicle. The structural support assembly can include a longitudinal frame element extending parallel to a longitudinal centerline of the vehicle and having an inner rail wall and an outer rail wall, a cross member operatively coupled to the longitudinal frame element and extending substantially perpendicular to the longitudinal centerline, and an internal frame reinforcement element operatively coupled only to the inner rail wall of the longitudinal frame element. The internal frame reinforcement element can be located near an intersection of the cross member and the longitudinal frame element.

[0004] In another exemplary embodiment, a vehicle frame can be provided for a ladder-frame vehicle. The vehicle frame can include a first longitudinally extending frame element spaced laterally from a longitudinal centerline of the ladder-frame vehicle, a second longitudinally extending frame element spaced laterally from the longitudinal centerline on a side opposite the longitudinal centerline relative to the first longitudinal frame element, and a cross member that operatively couples the first and second longitudinal frame elements and extends substantially perpendicular to the longitudinal centerline. Each of the first and second longitudinal frame elements can include a respective instance of an inner rail wall closest to the longitudinal centerline and an outer rail wall further away from the longitudinal centerline.Each of the first and second longitudinal frame elements can also include an internal frame reinforcement element, which is only operatively coupled to the inner rail wall near a crossing of the crossbeam and one of the respective first and second longitudinal frame elements. BRIEF DESCRIPTION OF THE MULTIPLE VIEWS OF THE DRAWING(S)

[0005] Having thus described the invention in general terms, reference is now made to the attached drawings, which are not necessarily drawn to scale and in which the following applies: Fig. Figure 1 illustrates a partially isolated top view of a frame assembly of a vehicle according to an exemplary embodiment; Fig. Figure 2 illustrates a perspective view of one side of the frame assembly (i.e., a structural support assembly) according to an exemplary embodiment; Fig. Figure 3 illustrates a top view of a pipe transverse element within a longitudinal frame element, with an upper wall removed to illustrate the placement of the pipe transverse element relative to an inner and outer rail wall of the longitudinal frame element according to an exemplary embodiment; and Fig. Figure 4 illustrates a cross-sectional view of the structural support assembly according to an exemplary embodiment. DETAILED DESCRIPTION

[0006] Some exemplary embodiments are now described in more detail below with reference to the accompanying drawings, which depict some, but not all, of the exemplary embodiments. In fact, the examples described and illustrated in this document should not be construed as limiting the scope, applicability, or configuration of the present disclosure. Rather, these exemplary embodiments are provided to enable this disclosure to meet applicable requirements. The same reference numerals refer throughout to the same elements. Furthermore, the expression "or," as used in this document, is to be interpreted as a logical operator that evaluates to true if one or more of its operators are true.As used in this document, functional coupling is understood to mean a direct or indirect connection which in any case enables a functional connection between components that are functionally coupled to each other.

[0007] As noted above, a balance between the performance attributes of the frame assembly reinforcement in response to frontal and offset barrier events may be desirable. Exemplary embodiments may provide internal lateral reinforcement that is partially decoupled from the inner frame while being strategically positioned for energy management. In this respect, for example, providing a tubular transverse element welded to only one side of a longitudinal frame member may provide engagement of an offset reinforcement structure laterally across the vehicle for an offset barrier event, while simultaneously limiting any reduction in the deformable retraction space for a frontal barrier event.The tubular cross member, used to provide internal reinforcement in exemplary embodiments, can provide a robust lateral load path in the event of an offset barrier event from an external structural cantilever (or deflector / deflection arm) by being located near a frame cross member. Furthermore, the use of a tubular cross member can also limit the longitudinal footprint of the reinforcement, thereby enabling an increased length of deformable retraction in response to a frontal barrier event, while providing a load consolidator to trigger additional deformable retraction.

[0008] In the sense used in this text, the term "deformable retraction" refers to the reduction in length of a structural element when the structural element deforms in response to a force or load exceeding the maximum compressive stress a solid structure can withstand without structural compromise (i.e., when the compressive strength of the material is exceeded). Deformable retraction (or deformable compression), a well-known phenomenon associated, for example, with placing one's full weight on an aluminum beverage can, is a useful energy absorber in response to barrier events involving other vehicles or objects. Accordingly, the management and strategic use of deformable retraction can be valuable for managing the momentum that vehicle occupants may experience when a barrier event occurs.Exemplary embodiments provide a pipe transverse element that is attached to the longitudinal frame element both strategically and at a strategic position to maximize the energy management performance of the longitudinal frame element in response to frontal and offset barrier events.

[0009] Fig. Figure 1 illustrates a partially isolated top view of a frame assembly 100 of an exemplary embodiment that can be used on a vehicle with a ladder frame body, whereas Fig. 2 is concentrated only on one side of the frame assembly 100. The frame assembly 100 comprises a first longitudinal frame element 110 and a second longitudinal frame element 112, each of which can extend substantially parallel to a longitudinal centerline 114 of the vehicle and equidistant from it. The first and second longitudinal frame elements 110 and 112 can therefore be understood as corresponding to a left and a right frame element (or vice versa). Each of the first and second longitudinal frame elements 110 and 112 can be formed from an elongated hollow metal structure (or a tube). In some cases, the first and second longitudinal frame elements 110 and 112 can further be structured to have a substantially rectangular cross-sectional shape.Thus, for example, the first and second longitudinal frame elements 110 and 112 can each have a substantially rectangular inner rail wall 111 facing a substantially rectangular outer rail wall 113, and are connected at their respective top and bottom surfaces (relative to the ground) by substantially rectangular upper and lower rail walls to delimit a cavity within the first and second longitudinal frame elements 110 and 112, respectively. The first and second longitudinal frame elements 110 and 112 can each also exhibit slight bends and changes in width or height at various points along their lengths, but can generally be mirror images of each other about the longitudinal centerline 114.

[0010] In Fig. 1 and Fig. 2 is a section removed from each of the first and second longitudinal frame elements 110 and 112 to provide visual access to the hollow interior of the first and second longitudinal frame elements 110 and 112 at a location where a pipe cross element 120 is provided for reinforcement. Removed sections of the first and second longitudinal frame elements 110 and 112 behind the pipe cross element 120 are in Fig. Figure 1 is shown in dashed lines. Furthermore, the tubular transverse element 120 is also arranged on a section of each of the first and second longitudinal frame elements 110 and 112, located near a crossbeam 130 that provides lateral reinforcement by extending between the first and second longitudinal frame elements 110 and 112. The tubular transverse element 120 of this example may have a substantially cylindrical core, which in some cases may be hollow. In addition, the tubular transverse element 120 may have flared longitudinal ends, which in some cases define a coil shape. However, other shapes and structures may be employed in alternative embodiments.

[0011] The frame assembly 100 can also include two separate instances (i.e., one on each side of the vehicle) of a deflector assembly 140. The deflector assembly 140 can include a deflector arm 142 having a curved or arcuate shape extending from one of the first and second longitudinal frame elements 110 and 112, respectively. Each instance of the deflector assembly 140 can include two interface sections that operatively couple opposite ends of the deflector arm 142 of the deflector assembly 140 to one of the first and second longitudinal frame elements 110 and 112, respectively. In this respect, a first interface, located at a distal or forward end of the corresponding first and second longitudinal frame elements 110 and 112, can be configured as a sliding interface.The sliding interface can include a sliding support 143 which is operatively connected to a distal end of the deflector arm 142 and bends inwards to extend around the outer walls of the corresponding first and second longitudinal frame elements 110 and 112 or near the front (or distal) end of the corresponding first and second longitudinal frame elements 110 and 112.

[0012] A second interface can be a fixed interface at a proximal end of the deflector arm 142, which couples the deflector arm 142 to an outer surface (e.g., the outer rail wall 113) of the corresponding first and second longitudinal frame elements 110 and 112. In some cases, the fixed interface can be provided by a coupling bracket 144, which is fixed to the outer rail wall 113 of the corresponding first and second longitudinal frame elements 110 and 112.Each instance of the deflector assembly 140 can therefore be understood as extending outwards and away from the corresponding first and second longitudinal frame elements 110 and 112 in a direction that represents the deflector assembly 140, in order to initially absorb any energy exerted in response to an offset barrier event, whereas the first and second longitudinal frame elements 110 and 112 typically initially absorb energy exerted in response to a frontal barrier event.

[0013] The coupling bracket 144 can be operatively coupled to the deflector arm 142 and the outer surface of the corresponding first and second longitudinal frame elements 110 and 112 by any suitable means. For example, one or more instances of a welded joint, a bolt or other fastening element, a shear pin, or the like can operatively couple the coupling bracket 144 to the deflector arm 142 and the outer surface of the outer rail wall 113 of the corresponding first and second longitudinal frame elements 110 and 112. In an exemplary embodiment, the coupling bracket 144 can be operatively coupled via a shear pin 147 (see Fig. 3) or another physical connection designed to shear or break at or near a predetermined force level that may occur in connection with a displaced barrier event, attached to the corresponding first and second longitudinal frame elements 110 and 112 and / or the deflector arm 142. In some cases, the coupling bracket 144 may be attached to the corresponding first and second longitudinal frame elements 110 and 112, and the shear pin 147 may attach the coupling bracket 144 to the deflector arm 142, as shown in Fig. 3 shown. In particular, after the shear pin 147 has broken in response to the application of force, the deflector arm 142 can also slide along the first or the second longitudinal frame element 110 or 112 to further provide deformable retraction and energy absorption.

[0014] Fig. Figure 3 illustrates a top view of the pipe cross element 120 inside the second longitudinal frame element 112, with the upper rail wall removed to expose the pipe cross element 120. Fig. Figure 3 also provides a clear view of how the pipe cross element 120 forms an interface with the inner rail wall 111 and is positioned relative to the coupling bracket 144 and the crossbeam 130. Fig. Figure 4 illustrates a cross-sectional view (looking from above and downwards) of the first longitudinal frame element 110, which also shows the above in relation to Fig. The three relationships mentioned above demonstrate this. With reference to... Fig. 1-4 It should be noted that in some embodiments the coupling bracket 144 may have a longitudinal length (i.e., a length substantially parallel to the longitudinal centerline 114) that overlaps with the pipe transverse element 120. In this respect, for example, a length (L cThe coupling bracket 144 is longer than the diameter (D1) of the pipe cross member 120 and can completely overlap the diameter (D1) of the pipe cross member 120 on the outside of the outer rail wall 113. Meanwhile, the width (Wc) of the cross member 130 can only partially overlap the diameter (D1) of the pipe cross member 120. Furthermore, in some cases, the width (Wc) of the cross member 130 can be significantly wider than the diameter (D1) of the pipe cross member 120, but the overlap of the width (Wc) of the cross member 130 and the pipe cross member 120 over the inner rail wall 111 can be less than half the diameter (D1) of the pipe cross member 120.

[0015] During a frontal barrier event, it may be desirable to maximize the length of the first and second longitudinal frame elements 110 and 112 available for deformable retraction, since the total length capable of deformable retraction absorbs energy from the barrier event that is not transferred to any occupant. Conversely, if the tube cross-element 120, which is an example of an internal frame reinforcement element, is fixed to an inner surface of either the inner rail wall 111 or the outer rail wall 113, the corresponding section of the inner rail wall 111 or the outer rail wall 113, which is reinforced by being fixed to the tube cross-element 120, may not be capable of deformable retraction. However, if only one side (e.g., the inner rail wall 111) of the tube cross-element 120 is fixed, then the other side (e.g., the outer rail wall 113) remains free.the outer rail wall 113) is capable of deformable retraction and thereby also increases energy absorption.

[0016] In one exemplary embodiment, the pipe transverse element 120 can actually be spaced apart from the outer rail wall 113 to ensure that the outer rail wall 113 retains the capacity for deformable retraction and corresponding energy absorption in this region. The space between them can be provided by a gap 180. The gap 180 can be small, in some cases between approximately 5 mm and 10 mm in length, although alternatively, any length for the gap 180 in the range of approximately 0.1 mm to approximately 10 mm can be used.

[0017] In some cases, by providing the aforementioned relative placement (e.g., with overlap of both the crossbeam 130 and the coupling bracket 144 relative to the diameter of the pipe cross element 120), further advantageous energy absorption for the vehicle's transverse stiffness can be provided, since the deflector assembly 140 can transfer energy to the pipe cross element 120 upon contact during an offset barrier event. The transfer of energy to the pipe cross element 120 can initially occur via energy applied to the deflector arm 142 and the coupling bracket 144, which is then transferred to the outer rail wall 113 to close the gap 180 and initiate contact with the pipe cross element 120.Energy applied to the pipe cross element 120 can then be communicated to the crossbeam 130 and deformable retraction of the crossbeam 130 can be facilitated to further absorb energy and manage energy dissipation.

[0018] Thus, the gap 180, in combination with the relative positioning described above, provides at least a twofold advantage for the frame assembly 100. In this respect, a first advantage can involve increasing the quantity of the first or second longitudinal frame element 110 or 112, which remains capable of deformable retraction by providing, for a frontal barrier event, a compression force in the direction of arrow 190. Fig.3 provides that reinforcement of the outer rail wall 113 is unnecessary (since it is only attached to the inner rail wall 111). Attaching the pipe cross-element 120 only to the inner rail wall 111 therefore allows essentially the entire outer rail wall 113 (especially in the region of the pipe cross-element 120) to be deformably retracted, and essentially the entire inner rail wall 111, with the exception of the small section fixed to the pipe cross-element 120 (and therefore having a length approximately equal to the diameter (D1) of the pipe cross-element 120), is available for deformable retraction and the associated energy absorption.

[0019] A second advantage is provided because the gap 180 also only provides a small space that needs to be removed during an offset barrier event to engage the deflector arm 142 with the pipe cross element 120 for energy transfer to the crossbeam 130. In this respect, in response to a compression force in one direction of arrow 192 during an offset barrier event, the deflector arm 142 can exert a force on the outer rail wall 113 to close the gap 180, while also absorbing energy due to its own deformable retraction. The force on the outer rail wall 113 can then be transferred via the pipe cross element 120 and the inner rail wall 111 to the crossbeam 130, which can deformably retract in one direction of arrow 194 to absorb further energy.Thus, the placement and attachment of the pipe cross element 120 relative to the crossbeam 130 and the deflector arm 142 can provide superior energy management in response to any barrier event.

[0020] A structural support assembly for a vehicle can therefore be provided. The structural support assembly can include a longitudinal frame element extending parallel to a longitudinal centerline of the vehicle and having an inner rail wall and an outer rail wall, a cross member operatively coupled to the longitudinal frame element and extending substantially perpendicular to the longitudinal centerline, and an internal frame reinforcement element operatively coupled only to the inner rail wall of the longitudinal frame element. The internal frame reinforcement element can be located near an intersection of the cross member and the longitudinal frame element.

[0021] The structural support assembly (or a vehicle frame for a ladder-frame body that incorporates such a structural support assembly) may, in some embodiments, include additional features, modifications, extensions, and / or the like to perform further functions or improve the assembly's performance. These additional features, modifications, extensions, and / or the like may be added in any combination. The following is a list of various additional features, modifications, and extensions, each of which may be added individually or in any combination. For example, the internal frame reinforcement element may be spaced apart from the outer rail wall to form a gap between the internal frame reinforcement element and the outer rail wall. In one exemplary embodiment, the gap may be between approximately 0.1 mm and 10 mm.In some cases, the structural support assembly may further include a deflector assembly extending away from the outer rail wall relative to the longitudinal centerline. The deflector assembly may have a first interface with a front portion of the longitudinal frame element and a second interface with a portion of the longitudinal frame element near the internal frame reinforcement element. In an exemplary embodiment, the first interface may be a sliding interface, and the second interface may include a coupling bracket operatively coupled to the outer rail wall. The coupling bracket may extend beyond both longitudinal ends of a diameter of the internal frame reinforcement element.In some cases, a width of the cross member may extend over an outer surface of the inner rail wall to overlap by less than half the diameter of the internal frame reinforcement element. In an exemplary embodiment, the deflector assembly may include an elongated element having an arcuate shape, extending from the longitudinal centerline from the second interface to the first interface. In some cases, a shear pin may operatively couple the elongated element to an outer surface of the outer rail wall at the second interface. In some cases, the internal frame reinforcement element may be configured as a tubular cross member having a substantially cylindrical core.

[0022] Many modifications and other embodiments of the inventions set forth in this document will be apparent to a person skilled in the art in the field to which these inventions belong, given the teachings presented in the preceding descriptions and the accompanying drawings. It is therefore understood that the inventions are not limited to the specific embodiments disclosed and that modifications and other embodiments are included within the scope of the appended claims. Furthermore, it is understood that, although the preceding descriptions and the accompanying drawings describe exemplary embodiments within the framework of certain exemplary combinations of elements and / or functions, different combinations of elements and / or functions can be provided by alternative embodiments without deviating from the scope of the appended claims.In this respect, other combinations of elements and / or functions than those expressly described above are also considered, as may be set forth in some of the appended claims. Where advantages, benefits, or solutions to problems are described herein, it is understood that such advantages, benefits, and / or solutions may be applicable to some exemplary embodiments, but not necessarily to all exemplary embodiments. Thus, all advantages, benefits, or solutions described in this document should not be considered critical, necessary, or essential for all embodiments or for the subject matter claimed herein. Although specific terms are used in this document, they are used only in a generic and descriptive sense and not for the purpose of limitation.

[0023] According to the present invention, a structural support assembly for a vehicle is provided, comprising: a longitudinal frame element extending parallel to a longitudinal centerline of the vehicle and having an inner rail wall and an outer rail wall; a cross member operatively coupled to the longitudinal frame element and extending substantially perpendicular to the longitudinal centerline; and an internal frame reinforcement element operatively coupled only to the inner rail wall of the longitudinal frame element, wherein the internal frame reinforcement element is arranged near an intersection of the cross member and the longitudinal frame element.

[0024] According to one embodiment, the internal frame reinforcement element is arranged at a distance from the outer rail wall in order to form a gap between the internal frame reinforcement element and the outer rail wall.

[0025] According to one embodiment, the gap is between approximately 0.1 mm and 10 mm.

[0026] According to one embodiment, the invention is further characterized by a deflector assembly extending away from the outer rail wall relative to the longitudinal centerline, wherein the deflector assembly includes a first interface with a front section of the longitudinal frame element and a second interface with a section of the longitudinal frame element near the internal frame reinforcement element.

[0027] According to one embodiment, the first interface comprises a sliding interface.

[0028] According to one embodiment, the second interface comprises a coupling bracket that is operatively coupled to the outer rail wall, and wherein the coupling bracket extends beyond both longitudinal ends of a diameter of the internal frame reinforcement element.

[0029] According to one embodiment, a width of the crossbeam extends over an outer surface of the inner rail wall to overlap by less than half the diameter of the internal frame reinforcement element.

[0030] According to one embodiment, the deflector assembly comprises an elongated element having an arc-shaped form that extends from the longitudinal centerline away from the second interface to the first interface.

[0031] According to one embodiment, a shear pin couples the elongated element at the second interface to an outer surface of the outer rail.

[0032] According to one embodiment, the internal frame reinforcement element comprises a tube transverse element having a substantially cylindrical core.

[0033] According to the present invention, a vehicle frame for a ladder-frame vehicle is provided, comprising: a first longitudinally extending frame element that is spaced laterally from a longitudinal centerline of the ladder-frame vehicle; a second longitudinally extending frame element that is spaced laterally from the longitudinal centerline on a side opposite the longitudinal centerline relative to the first longitudinal frame element;and a crossbeam operatively coupling the first and second longitudinal frame elements and extending substantially perpendicular to the longitudinal centerline, each of the first and second longitudinal frame elements comprising a respective instance of an inner rail wall closest to the longitudinal centerline and an outer rail wall further away from the longitudinal centerline, each of the first and second longitudinal frame elements further comprising an internal frame reinforcement element operatively coupled to the inner rail wall only near an intersection of the crossbeam and a respective of the first and second longitudinal frame elements.

[0034] According to one embodiment, the internal frame reinforcement element is arranged at a distance from the outer rail wall in order to form a gap between the internal frame reinforcement element and the outer rail wall.

[0035] According to one embodiment, the gap is between approximately 0.1 mm and 10 mm.

[0036] According to one embodiment, the invention is further characterized by a deflector assembly extending away from the outer rail wall relative to the longitudinal centerline, wherein the deflector assembly includes a first interface with a front section of the respective first and second longitudinal frame elements and a second interface with a section of the respective first and second longitudinal frame elements near the internal frame reinforcement element.

[0037] According to one embodiment, the first interface comprises a sliding interface.

[0038] According to one embodiment, the second interface comprises a coupling bracket that is operatively coupled to the outer rail wall, and wherein the coupling bracket extends beyond both longitudinal ends of a diameter of the internal frame reinforcement element.

[0039] According to one embodiment, a width of the crossbeam extends over an outer surface of the inner rail wall to overlap longitudinally by less than half the diameter of the internal frame reinforcement element.

[0040] According to one embodiment, the deflector assembly comprises an elongated element having an arc-shaped form that extends from the longitudinal centerline away from the second interface to the first interface.

[0041] According to one embodiment, a shear pin couples the elongated element to an outer surface of the outer rail wall at the second interface.

[0042] According to one embodiment, the internal frame reinforcement element comprises a tube transverse element having a substantially cylindrical core.

Claims

[1] Structural support assembly for a vehicle, wherein the structural support assembly comprises: a longitudinal frame element that extends parallel to a longitudinal centerline of the vehicle and has an inner rail wall and an outer rail wall; a crossbeam which is operatively coupled to the longitudinal frame element and extends essentially perpendicular to the longitudinal centerline; and an internal frame reinforcement element that is only operatively coupled to the inner rail wall of the longitudinal frame element, wherein the internal frame reinforcement element is located near a crossing of the cross member and the longitudinal frame element. [2] Structural support assembly according to claim 1, wherein the internal frame reinforcement element is spaced apart from the outer rail wall to form a gap between the internal frame reinforcement element and the outer rail wall. [3] Structural support assembly according to claim 2, wherein the gap is between about 0.1 mm and 10 mm. [4] Structural support assembly according to claim 1, further comprising a deflector assembly extending away from the outer rail wall relative to the longitudinal centerline, wherein the deflector assembly includes a first interface with a front section of the longitudinal frame element and a second interface with a section of the longitudinal frame element near the internal frame reinforcement element. [5] Structural support assembly according to claim 4, wherein the first interface comprises a sliding interface. [6] Structural support assembly according to claim 4, wherein the second interface comprises a coupling bracket which is operatively coupled to the outer rail wall, and wherein the coupling bracket extends beyond both longitudinal ends of a diameter of the internal frame reinforcement element. [7] Structural support assembly according to claim 6, wherein a width of the cross member extends over an outer surface of the inner rail wall to overlap by less than half the diameter of the internal frame reinforcement element. [8] Structural support assembly according to claim 4, wherein the deflector assembly comprises an elongated element having an arc-shaped form extending from the longitudinal centerline away from the second interface to the first interface. [9] Structural support assembly according to claim 8, wherein a shear pin couples the elongated element at the second interface to an outer surface of the outer rail wall. [10] Structural support assembly according to claim 1, wherein the internal frame reinforcement element comprises a tube transverse element having a substantially cylindrical core. [11] Vehicle frame for a vehicle with a ladder frame, wherein the vehicle frame comprises the structural support assembly according to one of claims 1-10, wherein the longitudinal frame element comprises a first longitudinally extending frame element which is spaced laterally from a longitudinal centerline of the vehicle with a ladder frame and the structural support assembly further a second longitudinally extending frame element, spaced laterally from the longitudinal centerline on a side opposite the longitudinal centerline relative to the first longitudinal frame element, wherein the crossbeam operatively couples the first and second longitudinal frame elements, and wherein each of the first and second longitudinal frame elements includes a respective instance of an inner rail wall closest to the longitudinal centerline and an outer rail wall further away from the longitudinal centerline, wherein each of the first and second longitudinal frame elements further includes an internal frame reinforcement element which is only operatively coupled to the inner rail wall near a crossing of the crossbeam and a respective of the first and second longitudinal frame elements.

Images