Floor structure of a motor vehicle body

A floor structure of a motor vehicle body is disclosed as having a floor panel and a support structure arranged below the floor panel. Two cross members substantially extend in vehicle transverse direction and are spaced from one another in vehicle longitudinal direction. The end sections of the cross members facing the same vehicle side are connected to one another via a profile part, each substantially extending in vehicle longitudinal direction, which extends along a side member arrangement and supports itself on the side member arrangement.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority to German Patent Application No. 102013004793.5 filed Mar. 20, 2013, which is hereby incorporated by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to a floor structure of a motor vehicle body having a floor panel and a support structure arranged below the floor panel, which is designed as a seat support structure for fastening vehicle seats to the floor structure.

BACKGROUND

In motor vehicle body construction there exist various concepts for realizing a floor structure to be provided, for example, in the region of a passenger compartment of the motor vehicle. Known floor structures typically have a center tunnel extending over almost the entire length of the passenger compartment and running in the middle above the floor structure and seat cross members separately provided for fastening vehicle seats which are arranged on the top side of a floor panel. The actual floor panel in this case is mostly formed in multiple parts, and typically adjoins the center tunnel approximately laterally with individual floor panel segments.

Thus, a floor structure of a motor vehicle body with a floor panel is known, for example from DE 10 2011 015 541 A1, wherein a seat support structure is provided below the floor panel. The floor panel in this case includes two floor sections adjoining one another in vehicle longitudinal direction (x), which, based on the vehicle vertical direction (z), are arranged offset to one another. The seat support structure in this case has at least one transverse structure stabilizing the floor section in the region of the floor section located higher with two cross members which are spaced from one another in vehicle longitudinal direction (x). A front cross member and a rear cross member in this case lie on two lateral side members substantially extending in vehicle longitudinal direction (x) and are fastened thereon. The ends of those cross members in this case are only joined to the side members of the vehicle body with their end sections located opposite in a point-like manner.

In contrast with this, the present disclosure is based on the object of providing a floor structure of a motor vehicle body which is improved with respect to its bending and structural stiffness. This is to contribute to increasing possible oscillation natural frequencies of the motor vehicle body in order to counteract possible resonance and vibration effects which develop during the operation of the vehicle. In addition to this, the floor structure is to provide improved occupant protection and optimize an intrusion behavior of the motor vehicle body, for example, in the region of the passenger compartment upon a lateral or laterally offset impact of the body against an obstacle, such as against a post or tree.

In addition to this, the present disclosure provides an increased torsional stiffness of the motor vehicle body and of the seat fastening, which is preferably accompanied by a weight reduction and which furthermore, makes possible a preferably simple, production-rational and cost-effective fabrication of the body.

SUMMARY

Accordingly, a floor structure of a motor vehicle body is provided, which includes a floor panel and a support structure arranged below the floor panel. The support structure includes two cross members which are spaced from one another in vehicle longitudinal direction (x) and substantially extend in vehicle transverse direction (y). End sections of the cross members located opposite are connected to one another via a profile part each substantially extending in vehicle direction (x).

Here, the end sections of the cross members which face the same vehicle side are connected to one another by means of the profile part. Based on the geometry of the floor structure, the end sections of the two cross members facing a left vehicle side are connected to one another via a left profile part, while right end sections of the two cross members located opposite are connected to one another via a right profile part. The profile parts which connect the cross members to one another extend along a side member arrangement of the floor structure and support themselves on the side member support structure.

Here, it is provided that the profile parts over their entire extension support themselves over the side member arrangement, each being provided on the left or right on the floor structure. In this way, an alternating contact surface of profile part and side member arrangement can be maximized. In that a single profile part is simultaneously connected to the end sections of both cross members spaced from one another in vehicle longitudinal direction (x), the cross members cannot only be subjected to a point-like support but to a comparatively large-area support on the side member arrangement via the profile part.

By means of the profile part, the end sections of the cross members can be separately connected to one another, and accordingly be fastened to the side member arrangement in a reinforced manner. In the case of external load actions into the floor structure, such as during a side impact, forces acting on the floor structure approximately in the middle between the cross members can be transmitted via the profile part in a more controlled and quite even manner onto both cross members and accordingly discharged into the floor structure.

In this way, the bending and torsional stiffness of the floor structure, thus of the entire vehicle body, can be increased. Furthermore, in a region located between the cross members further body components such as a B-pillar can adjoin the floor structure. Through the structural reinforcement of the floor structure by means of the profile, body components adjoining in such a manner can be formed under certain conditions in a more thin-walled manner or with a reduced number of parts or components so that altogether a weight saving can result.

According to a further configuration, the side member arrangement includes an inner side sill profile and a longitudinal frame profile. Side sill profile and longitudinal frame profile in this case can run adjoining one another substantially in vehicle longitudinal direction (x). The longitudinal frame profile in this case is formed as an extension extending against the travelling direction of a side member adjoining the front wall of the motor vehicle body.

The two-part configuration of the side member arrangement is advantageous for the connecting of the profile part in that the profile part can support itself along both profiles, side sill profile and longitudinal frame profile. Here it is provided that the profile part connecting the two cross members to one another extends both along the side sill profile and also along the longitudinal frame profile, and that the profile part furthermore is structurally connected both to the side sill profile and also to the longitudinal frame profile.

Here, multiple structural connections of the profile part both to the side sill profile and also to the longitudinal frame profile is provided. Transverse force action into the floor structure can thus be particularly favorably transmitted from the side member arrangement to the profile part, and finally discharged into both cross members which are connected to the profile part.

According to a further development, it is provided that the profile part supports itself on an inner side of the inner side sill profile. Because of this it can be achieved that the two end sections of the cross members which are connected to the profile part also come to contact the side sill profile on the inside. Any forces acting or deformations acting on the side sill profile from the outside can thus be discharged into the cross members at the face end.

Through this arrangement, the cross members can structurally reinforce the inner side sill profile combined with the respective profile part provided on the left and right and improve its intrusion or deformation behavior.

According to a further configuration, the profile part is formed as a closing plate for the longitudinal frame profile. Profile part and longitudinal frame profile can in this regard form a closed hollow profile. Upon an arrangement of the longitudinal frame profile on the side sill profile and with the additionally provided supporting of the profile part on the side sill profile the hollow profile of the side member arrangement can also be formed by the longitudinal frame, the profile part and the side sill profile. Profile sections of the longitudinal frame profile located opposite can thus be connected on the one hand to the profile part connecting the cross members and on the other hand to the side sill profile, while the profile part acting as closing plate can be connected on the one hand to the longitudinal frame profile and on the other hand to the side sill profile.

Through supporting and structurally connecting the profile part both on the side sill profile as well as on the longitudinal frame profile a described hollow profile can be formed, by means of which the bending and torsional stiffness as well as the overall stability of the side member arrangement can be increased.

According to a further configuration, the cross members which in vehicle longitudinal direction (x) are arranged offset relative to one another form a closed, largely rectangular support frame with the lateral profile parts connecting them for the floor panel to be fastened thereto. The configuration of a support frame formed by cross members and lateral profile parts makes possible a modular design of the floor structure. Thus, the support frame formed approximately rectangularly can be connected to the floor panel even prior to its assembly on the remaining floor structure, for example to the side member arrangement and thereby form a floor module.

The floor module thus formed can then be connected into a preconfigured structural unit with the remaining floor structure, for example, with the side member arrangements. The modular design, and in particular the advance arranging of the floor panel on the support frame makes possible forming individual structural connections of the components of the floor structure without access openings in the floor structure components. For example, the profile parts do not have to be provided for this purpose which usually act as access openings for welding tools or similar connecting means.

According to a further configuration, a front end section of the floor panel is connected to a left and to a right reinforcement profile. Left and right reinforcement profile in this case come to lie on opposite sides of a center tunnel. The two reinforcement profiles typically have a Z-shaped cross-sectional profile, wherein a rear flange section facing the front floor panel section is connected to the floor panel and/or to the front cross member of the floor structure, and wherein a profile section adjoining hereon and extending approximately vertically downwards acts as a kind of heel plate section, which forms a height offset between a front floor panel section and a floor panel section formed elevated and which adjoins hereon against the travelling direction.

The reinforcement profiles are formed overlapping or covering in vehicle transverse direction (y) and typically have a recess or a formed region, with which the reinforcement profiles can adjoin opposite sides of the center tunnel. In this regard, the left and right reinforcement profiles can form a further structural support for the longitudinal frame profile in vehicle transverse direction (y).

According to a further configuration, a structure-reinforcing insert piece is arranged between front cross member and at least one of the left or right reinforcement profiles. The insert piece can, for example, be provided in the overlap or connecting region of left and right reinforcement profile and can be arranged approximately in extension of a center tunnel, and serve for the structural reinforcement of the floor structure and the floor panel connection to the center tunnel.

According to a further configuration, left and right reinforcement profile are formed concavely curved at least in sections. The concave curvature in this case can be provided for adjoining the insert piece or adjoining the center tunnel. The reinforcement profile which in the plane that is formed by vehicle longitudinal direction (x) and vehicle vertical direction (z) and is approximately formed Z-shaped can follow an approximately L-shaped course formed in the plane formed by vehicle longitudinal direction (x) and vehicle transverse direction (y), wherein a short leg of the reinforcement profile substantially extending in vehicle longitudinal direction (x) can support itself in vehicle transverse direction (y) on the insert piece and/or on the center tunnel.

The concavely curved section in this case can have a curvature of approximately 90°, so that a longer leg of the L-shaped contour of the reinforcement profile following the shorter leg substantially extends in vehicle transverse direction (y). Through the arrangement of the reinforcement profile adjoining the insert piece and/or the center tunnel the transverse forces which are typically directed to the inside and which act on the reinforcement profile can be comparatively homogenously discharged or transferred into the center tunnel or into the reinforcement profile.

According to a further configuration, the outer ends, or the end sections of the reinforcement profiles located outside in vehicle transverse direction (y), support themselves on the inside on the side member arrangement, for example, on the inner sill profile. In this way, an additional support of the sill profile in vehicle transverse direction (y) can be formed. The inner sill profile can thus support itself not only via the cross member on the opposite sill profile, but via the reinforcement profile also directly on the center tunnel which is located approximately in the middle in the vehicle.

According to a further embodiment, the front cross member and at least one of the right or left reinforcement profiles form a closed hollow profile. The corresponding hollow profile in this case is formed, for example, in the plane that is formed by vehicle longitudinal direction (x) and vehicle vertical direction (z). Through the hollow profile configuration of front cross member and reinforcement profile the region of the support frame or of the floor module formed by support frame and floor panel located in the front in travelling direction can also be already formed particularly stable, and torsionally stiff even prior to installation in the motor vehicle body.

As a further development thereof, the hollow profile can also be formed by the front cross member, at least one the right or left reinforcement profile and the insert piece in a region approximately located in the middle between the profile parts, wherein the insert piece delimits the hollow profile in travelling direction.

According to a further development, the side member arrangement is formed continuously in a connecting region located in contact position with the profile part interconnecting the cross members. This means the side member arrangement has no through-openings or such structurally weakening contours in the connecting region to the profile part which would be required as access possibility for any connecting means, for example, welding tongs.

Such a through hole-free configuration of the side member arrangement can be achieved through the module construction and assembly of the floor structure. Since usual through-openings for welding tools which were usual up to now are now no longer a mandatory requirement, the stability and integrity of the side member arrangement, of its longitudinal frame profile and of its side sill profile can be advantageously increased.

Finally it is provided according to a further configuration that at least one of the cross members in a connecting region adjoining the lateral profile part has cross-sectional profile which becomes larger. Thus, at least one of the cross members, for example starting out from a middle section towards the outside, have a cross-sectional profile facing in vehicle transverse direction which continuously becomes larger. Through a cross-sectional structure which diverges towards the outside and becomes larger in such a manner the mechanical load absorption and a corresponding force discharge in the case of forces acting laterally into the floor structure can be improved and increased.

According to a further independent aspect, a motor vehicle body is finally provided, which has a previously described floor structure.

Furthermore, a motor vehicle is provided which is equipped with the previously described floor structure.

Finally, according to a further independent aspect, a production method for producing or forming a previously described floor structure is provided. In a first step, a support structure is formed here, which includes two cross members substantially extending in vehicle transverse direction (y) which are spaced from one another in vehicle longitudinal direction (x).

Here, the lateral end sections of the cross members, in particular those which face the same vehicle side, are each connected to a profile part substantially extending in vehicle longitudinal direction. This produces an approximately rectangular support structure with a front and rear cross member and a left and a right profile part.

The support structure thus formed is then connected to a floor panel, which is placed onto the support structure and structurally connected to support structure. In particular, the floor panel is welded to the support structure for forming a preconfigured floor module.

Following its completion, the floor module is arranged on two side member arrangements which are spaced from one another in vehicle transverse direction (y) and connected to these. The floor module preconfigured and provided with the floor panel in such a manner makes possible a connection to the side member arrangement without any through or access openings for connecting means, such as for example for welding tools, having to be provided in the side member arrangements. In this regard, the side member arrangements can be formed free of through-openings.

In a further development, the floor module can furthermore be provided with left and right reinforcement profiles, which are to be provided adjoining a front end section of the floor panel. Furthermore, the floor module can be provided with an insert piece that has to be arranged on the front cross member approximately in the middle, which together with the front cross member and with at least one right or left reinforcement profile can form a hollow profile in the region of the front cross member.

DETAILED DESCRIPTION

FIG. 1shows a floor panel10with a floor panel section12which is substantially formed flat and elevated and with a rear floor panel section14adjoining thereon against the travelling direction2of the motor vehicle. The rear floor panel section14is arranged with respect to the vehicle vertical direction (z) offset from the elevated, middle floor panel section12. It is located slightly lower than the middle floor panel section12.

The floor panel10, the region of the elevated floor panel section12located at the front in travelling direction2is furthermore provided with a left floor panel reinforcement16and with a right floor panel reinforcement18. The two floor panel reinforcements16,18shown inFIG. 2in isolated perspective representation each have an approximately L-shaped contour in the x-y plane considered on its own. In the x-z plane, the left and the right floor panel reinforcement16,18are formed approximately Z-shaped.

The reinforcement profiles16,18are arranged overlapping towards the vehicle middle and form a corresponding overlap region20. As is indicated inFIG. 1, the two reinforcement profiles16,18are multiply structurally connected to one another in their overlap region20. Here, structural connecting techniques provide for example welding connections, riveting connections, gluing connections but also a penetration joining of overlapping sheet metal components. Representative of all mentioned connecting types, various spot welds24are indicated for example inFIG. 1. As shown there, the two reinforcement profiles16,18are connected to one another in the overlap region20substantially extending in vehicle longitudinal direction (x).

The front end section of the elevated floor panel section12furthermore is supported on a rear flange section16a,18aof the two reinforcement profiles16,18extending approximately horizontally. In that overlap region, the reinforcement profiles16,18are each structurally connected separately to the front end section of the floor panel section12.FIG. 3shows a support frame30which includes two cross members32,34which are spaced from one another in vehicle longitudinal direction (x). The end sections32a,34aas well as32b,34bof the cross members32,34facing the same vehicle side are each connected to one another via a profile part36,38extending approximately in vehicle longitudinal direction (x).

The cross members32,34with the two profile parts36,38form the support frame30which is closed in circumferential direction and formed approximately rectangularly. The cross members32,34are formed double L-shaped in cross section. That double L-shaped contour is illustrated on the example of the rear cross member34inFIG. 3. Facing in travelling direction2and on its front end section, the rear cross member34includes a flange section34coriented approximately horizontally for supporting the floor panel section12. Adjoining this, a profile section34dprojecting downwards and extending approximately vertically is provided, which in turn merges into a profile section34eprojecting to the back and substantially extending horizontally. The rear end of that horizontal profile section34efinally merges into a flange section34fprojecting downwards.

The front cross member32has a double L-shaped cross-sectional contour corresponding herewith. As becomes clear by means ofFIG. 3at least the rear cross member34, preferably also the front cross member32, has a cross-sectional profile which becomes larger towards its longitudinal ends34a,34band32a,32brespectively. As is evident from the rear cross member34inFIG. 3, the approximately vertically oriented profile section34d, starting out approximately from the middle of the cross member34, is subjected to a steady enlargement towards its lateral end sections34a,34b. Through such a diverging configuration, a load and force transmission between the profile parts36and38and the cross members32,34can be improved.

InFIG. 3, an insert piece22which is provided approximately in the middle on the front cross member32is shown. This includes a front wall section22aextending approximately in the y-z plane with sections22b,22cwhich adjoin thereon and are curved in the x-y plane. Those curved sections22b,22cof the insert piece22are formed corresponding to corresponding curvatures16c,18cof the reinforcement profile16,18shown inFIG. 2. Because of those curved sections18c,16cas well as22b,22can improved load transmission in vehicle transverse direction (y), for example into a center tunnel5shown inFIG. 5can take place.

It must be noted, furthermore, that the two reinforcement profiles16,18shown inFIG. 2for example together with the insert piece22form a closing plate for the cross member32, so that from the two reinforcement profiles16,18, the front cross member32and the insert piece22fastened hereon a hollow profile31shown in cross section inFIG. 6can be formed. Towards the front, adjoining hereon in travelling direction2, the center tunnel5penetrating the front wall3of the floor structure1extends, while against the travelling direction2, adjoining the closed hollow profile31, the middle floor section12, which is elevated with respect to a front floor section11, follows.

FIG. 4shows the formation of a floor module50in perspective representation. The floor panel10provided with the reinforcement profiles16,18in this case is connected to the support frame30in such a manner that the reinforcement profiles16,18come to lie in the region of the front cross member32and that a shoulder which is formed between elevated floor panel section12and rear floor panel section14comes to lie in the region of the rear cross member34.

In this regard, the middle floor panel section12which with respect to a front floor panel section11and a rear floor panel section14is formed elevated can be supported by the two cross members32,34and suitably carried. The elevated floor panel section12which is formed opposite the front floor panel section11and rear floor panel section14can serve for the space-saving housing of motor vehicle components, for example, of energy storage devices.

The floor module50formed by the floor panel10and the support frame30can then be connected as a preassembly unit in one piece to the remaining components of the floor structure1, to their side member arrangements46,48. A final assembly state in this case is shown inFIG. 5. The floor structure1shown there includes two front side members4,6, which adjoin a front wall3from the front, and which extend along lateral side sill profiles40,42.

FIG. 7shows the connection of the floor module50to the side sill profile40and the longitudinal frame profile44with the help of the left side member arrangement46. That cross section B-B in this case extends through the front cross member32. For forming the floor module50, the front cross member32is connected to the lateral profile part36via two spot welds25which are merely shown exemplarily. Here, the profile part36, as is evident from the cross section ofFIG. 7, simultaneously acts as closing plate for the longitudinal frame profile44extending along the side sill profile40.

The longitudinal frame profile44has a U-profile like configuration that is open at the top. With a flange section44aprojecting outwardly it adjoins the side sill profile40which is formed approximately C-like in cross section from the bottom. Oriented located opposite, towards the vehicle middle, the longitudinal frame profile44has a flange section44bwhich approximately extends in horizontal direction. A flange section36bof the profile part36which is correspondingly formed comes to lie on that flange section44b, wherein the profile part36located opposite, i.e. towards the outside of the motor vehicle, has a flange section36aextending approximately in vehicle vertical direction (z). By means of the flange section36a, the profile part36acting as a closing plate supports itself on the side sill profile40in vehicle transverse direction.

ViewingFIGS. 2 and 7together it is evident that the reinforcement profile16also directly supports itself on the side sill profile40with a flange section16dobliquely projecting away upwardly, so that the reinforcement profile16in this case can also be directly connected to the side sill profile40for example by means of a spot weld26.

Because the profile part36which acts as a closing plate supports itself over its entire longitudinal extension in vehicle longitudinal direction (x) on the inner side sill profile as well as on the longitudinal frame profile44adjoining thereon and running along the side sill profile40, a comparatively large or longitudinally extended connecting region45to the side member arrangement46,48can be provided for the cross members32,34which are connected to the profile part36.

Any transverse forces acting on the floor structure1in vehicle transverse direction (y), for example in the middle between the two cross members32,34, can be distributed over the adjoining cross members32,34via the profile part36through its direct arrangement along the side member arrangement46,48.

In the cross section according toFIG. 7, two welding tools52are indicated furthermore by means of which the flange sections44b,36bof the longitudinal frame profile44which come to lie on top of one another and of the profile part36can be connected. In a similar manner, the cross section according toFIG. 8shows the formation of spot welds26for the direct fastening of the floor panel section12to the side sill profile40and of the flange section36aof the profile part36to the side sill profile40.

In modification of the configuration shown inFIG. 7, the lateral flange section16dof the reinforcement profile can also extend downwards and thus, comparable to the flange section12aof the floor panel section12shown inFIG. 8, come to lie against the interior sill profile40. Conversely, the flange section12ashown inFIG. 8can also extend upwardly and support itself on the inner sill profile corresponding to the flange section16dshown inFIG. 7.

The cross section D-D according toFIG. 9furthermore shows a cross section through the floor structure10which is offset compared withFIG. 6in vehicle transverse direction (y). There, the reinforcement16which is formed approximately Z-shaped in cross section is shown with an upper horizontal flange section16aand with a lower horizontal flange section16b. While the reinforcement profile16supports itself on the front floor panel section11with its lower flange section16bfacing towards the front, the transition to the upper flange section16ahorizontally projecting towards the back opposite to the travelling direction, is provided with the cross member32arranged below.

As shown inFIG. 9, the cross member32, similar to the rear cross member34already described inFIG. 3, also has a double L-shaped cross-sectional profile with upper and lower flange section32c,32fand profile sections32d,32elocated in between. Through the geometrical configuration of front cross member32and the reinforcement profiles16,18a hollow profile31which is merely formed by the respective reinforcement profile16,18and the cross member32can also be provided outside the region of the insert piece22.

Finally it must be noted that the connecting spots or spot welds indicated with the reference numbers24,25and26reflect the assembly sequence of the floor structure1. In a first step, the cross members32shown inFIG. 3are thus connected to one another with the profile parts36,38located opposite by means of spot welds24. In the same operation, the insert piece22is also arranged on the front cross member32and structurally connected herewith.

Parallel to this and independently of the forming of the support frame30, the elevated floor panel section12can be connected to the reinforcement profiles16,18as indicated inFIG. 1.

In a following operation and subject to forming spot welds or connecting points25, the assembly of the preconfigured floor panel10to the support frame30is provided. Here, the floor panel10, and in particular its floor panel section12which is formed elevated is connected to the cross members32,34, as well as to the profile parts36,38, as is indicated by the spot welds according toFIGS. 6 and 7.

This is followed by the installation of the floor module50obtained in this way in the motor vehicle body or in the floor structure1. In a last operation, the spot welds26are placed, by means of which the floor module50is connected to the lateral side member arrangements46,48.

Finally, the method for producing the floor structure1is again briefly sketched inFIG. 10. Block100represents a first step to form the support structure and base plate. In the first step100, the support structure30which is shown isolated inFIG. 3is formed with the two cross members32,34which are spaced from one another in vehicle longitudinal direction (x) and substantially extend in vehicle transverse direction (y). In step100, the opposite end sections32a,34a,32b,34bof the two cross members32,34are connected each to profile parts36,37substantially extending in vehicle longitudinal direction (x). Block102represents a second step to form the floor or bottom module. In the second step102, the floor panel10which is preconfigured if applicable according toFIG. 1is connected to the previously formed support structure30for forming a floor module50. Block104represents a third step to connect the floor or base module and longitudinal beams. In the third step104the floor module50thus formed is connected to the two side member arrangements46,48.