Vehicle body structure with body reinforcement behind the second row of seats

This application is the U.S. National Stage of International Application No. PCT/EP2010/005887, filed Sep. 27, 2010, which designated the United States and has been published as International Publication No. WO 2001/03/8877 and which claims the priority of German Patent Application, Ser. No. 10 2009 047 810.8, filed Sep. 30, 2009, pursuant to 35 U.S.C. 119(a)-(d).

The invention relates to a vehicle body structure with a body reinforcement behind the second row of seats.

Such a generic body reinforcement is known from DE 10 2004 014 664 A1 and includes a beam assembly which is formed from two opposing longitudinal side beams, a floor crossbeam, and two vertical side beams. A left-side longitudinal side beam, an associated left end of the floor crossbeam, and a left-side vertical side beam are respectively connected to a left-side nodal point. Likewise, the second right-side longitudinal beam is connected with the right-side end of the floor crossbeam and the second right-side vertical side beam at a right-side nodal point. In addition, corner reinforcements are attached at both nodal points to provide increased stiffening in the transverse plane of the floor crossbeam and the vertical side beams.

Such corner reinforcements at the floor-side nodal points are well-suited and generally known measures to attain body stiffening in the rear body region, in particular against body twist as a result of operation and as protective measure against a crash from the side. DE 10 2004 027 377 A1 discloses, for example, an arrangement with a floor crossbeam which is guided on either end with a corner reinforcement over a longitudinal side beam and further is bent upwardly to a short vertical side beam element and connected with a wheel well carrier.

It is further generally known in the field of sedan bodies to improve the stiffness of the body in vehicles with a foldable rear bench seat in the area of the rear wheel wells and the rear window shelf by closing the generic beam assembly with an upper crossbeam to a torsional ring in the area of the rear window shelf. Also in this case, corner reinforcements of the floor-side nodal points are configured in a known manner by welding corner-reinforcing sheet-metal angles for material reinforcement.

A similar sheet-metal angle reinforcement is also implemented in a generally known manner in station wagons, using vertical side beams in the form of C-pillars which extend up to the roof region so as to realize also in this case a closed torsion ring via the roof structure.

The beam assembly arrangement disclosed in DE 10 2004 027 377 A1 has only a slight torsion-reducing effect as a result of the short vertical side beam attachment to the wheel wells. In addition, all beam assembly arrangements described above as related art are very complex to produce and to install, in particular when using separate corner reinforcement parts. Furthermore, each involves a conventional steel body construction without special measures to reduce weight.

In generally known modern vehicle bodies materials made of light metals or light metal alloys, in particular aluminum, are used in addition to aerodynamic designs to reduce fuel consumption in an environmentally friendly manner by saving weight. The stiffness and joining technologies for light metal components differ from the previous conventional, exclusive steel plate construction which poses problems that have to be solved with a material mix which is precisely adjusted to the respective site of the vehicle body, and a respective combination of components as well as cost-efficient and appropriate joining techniques for a use in large series.

It is an object of the invention to refine a generic vehicle body structure with body reinforcement behind the second row of seats in such a manner as to realize a cost-efficient and weight-beneficial structure with high stiffness.

This object is attained by constructing the longitudinal side beams as cast aluminum longitudinal side beams which have each formed and integrated thereon a corner reinforcement at each nodal point in the form of a corner reinforcing profile made of uniform material and protruding in a box-like manner. Connected to each of the two corner reinforcing profiles is the associated vertical side beam at the top, on one hand, and the associated end of the floor crossbeam on the side, on the other hand.

The use of a cast aluminum longitudinal side beam results in a weight-beneficial structure which can be easily and well suited to installation and stiffness demands. In addition, a corner reinforcing profile can be formed and integrated in such a casting in a simple and cost-efficient manner, without the need for additional corner reinforcement parts which have to be installed in addition. The direct connection of the floor crossbeam and a vertical side beam to a corner reinforcing profile also enables the application of a simple and stable joining technique so that the entire beam assembly for body reinforcement behind the second row of seats in the area of the rear wheel wells is especially weight-beneficial and cost-effective while effecting a good stiffening function.

To date, aluminum alloys are almost exclusively used as lightweight materials for cast and sheet metal elements in body construction and are designated in short as Alu-parts or aluminum parts also in the present application. Should other well-suited lightweight materials, such as for example magnesium alloys, become available in the future, the afore-mentioned is equally applicable for such materials and covered within the scope of protection.

According to a particularly preferred concrete embodiment, each cast aluminum longitudinal side beam has a cast aluminum beam shell member which faces the vehicle inner side and on which the corner reinforcing profile is formed as hollow profiled box which protrudes into the vehicle interior. The profiled box has a roughly triangular base shape to track the corner configuration to be reinforced and includes in vehicle longitudinal direction opposite roughly triangular box transverse walls, a box top wall, a box side wall, and a concavely formed transition zone.

A vertical side beam shell member facing towards the vehicle inner side is connected with a lap joint to formfittingly overlap the area of the box top wall or as an alternative engages behind a substantially U-shaped flange there. In like manner, a floor crossbeam shell member which faces towards the vehicle inner side is connected to the profiled box to formfittingly overlap with a lap joint the area of the box side wall. The floor crossbeam shell member is closed by the floor panel to form a floor crossbeam in the form of a hollow beam, when the body is fully assembled. Likewise, the vertical side beam shell members are closed by outer vehicle panels to form hollow beams.

The profiled box formed as described above in a cast aluminum beam shell member provides in conjunction with the indicated connection and joining techniques a particularly simple corner reinforcement which can be produced by casting in a cost-efficient manner, with the shell member also producible with reinforcing ribs in a particularly weight-beneficial manner and with relatively slight wall thicknesses and the required stiffness.

In addition, weight can be reduced while preventing contact corrosions by also producing the floor crossbeam or a floor crossbeam shell member, and the respective vertical side beam or a vertical side beam shell member, from aluminum sheet. The beam connections with the corner reinforcing profile are hereby advantageously realized by bonding and/or riveting. Possible joining processes for connecting the body parts further include MIG welding and FDS screws which advantageously require one-sided accessibility only for the connection site.

In sedan bodies, in particular in vehicles with foldable rear bench seats, the claimed beam assembly can be closed by an upper crossbeam in the area of a rear window shelf to form a floor corner reinforced torsion ring that has superior stiffness properties. The claimed beam assembly provides superior torsion reinforcement also in station wagons, in which case the vertical side beams are suitably components of the C-pillars that extend up into the roof area.

An exemplary embodiment of the invention will be described with reference to a drawing.

It is shown in:

FIG. 1 a perspective top view of part of a body with body reinforcement behind a second row of seats,

FIG. 2 an enlarged illustration of the area A of FIG. 1 ,

FIG. 3 a side bottom view upon the object of FIG. 2 in viewing direction B, and

FIG. 4 an illustration corresponding to FIG. 2 of an alternative embodiment.

FIG. 1 shows the rearward area of part of a body 1 for a sedan with foldable rear bench seat for increasing the trunk space. A torsion ring 3 is positioned in the area between opposite wheel wells 2 roughly in a vertical transverse plane for stiffening the body 1 . This torsion ring 3 includes a floor crossbeam 4 , a left-side vertical side beam 5 , and a right-side vertical side beam 6 as well as an upper crossbeam 7 in the area of and at level with a rear window shelf 8 for connecting the vertical side beams 5 , 6 . In addition, the torsion ring 3 is connected at the floor-proximal corner regions to a left-side longitudinal side beam 9 and a right-side longitudinal side beam 10 at nodal points 11 , respectively. The left-side nodal point 11 , according to the area A in FIG. 1 , is illustrated in detail with reference to FIGS. 2 and 3 .

FIG. 2 involves hereby an enlarged view of the area A of FIG. 1 , and FIG. 3 involves a side bottom view upon the object of FIG. 2 , with a viewing direction roughly according to arrow B of FIG. 2 . The longitudinal side beam 9 has a cast aluminum beam shell member 12 which has a shell outer side facing towards the vehicle inner side and which extends longitudinally along the left vehicle outer side and is complemented by an outer sheet to form a closed longitudinal hollow beam, when the body is finished. Formed on the cast aluminum beam shell member 12 in the transverse zone of the torsion ring 3 is a hollow profiled box 13 as corner reinforcing profile which protrudes into the vehicle interior.

The profiled box 13 has a basic box shape roughly in the shape of an L, including two opposite triangular box transverse walls 14 , 15 , a box side wall 17 as well as a concavely formed transition wall 18 between the top box wall 16 and the box side wall 17 . The view according to FIG. 3 further shows the reinforcement of the cast aluminum beam shell member 12 in the interior zone with suitably secured reinforcing ribs 19 to maintain the required stiffness.

The floor crossbeam 4 has a floor crossbeam shell member 20 which is placed upon a floor panel 21 for formation of a hollow beam. The floor crossbeam shell member 20 has an end to formfittingly overlap with a lap joint 22 the area of the box side wall 17 and is secured there through bonding and riveting. Likewise, a vertical side beam shell member 23 of the vertical side beam 5 formfittingly overlaps with a lap joint 24 the area of the box top wall 16 and is secured there also through bonding and riveting. The floor crossbeam shell member 20 and the vertical side beam shell member 23 are made of aluminum sheet.

The alterative embodiment according to FIG. 4 substantially corresponds to the afore-described embodiment so that same reference signs are used for same parts. The profiled box 13 is configured here differently, whereby the box profile is open to the vehicle inner side, instead of the transition wall 18 , and includes a central support web 25 . In addition, the vertical side beam shell member 23 is connected in a different way as in the first embodiment.

In this embodiment, the vertical side beam shell member 23 has an end which formfittingly engages from outside behind a U-shaped flange structure 26 in the area of the box top wall like a plug connection. This second variant is able to provide possible advantages during assembly of the body. The mode of action is basically the same as in the first embodiment.