Abstract:
The invention relates to a crossmember for a motor vehicle. Said crossmember ( 1 ) is composed of a base body ( 2 ) and a reinforcement ( 3 ) and has at least one wall ( 22 ) running transversally to the crossmember ( 1 ).

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a crossmember for a motor vehicle. 
   An aim of motor vehicle manufacturers is to reduce the weight of motor vehicles. For this reason, DE 100 46 120 A1 describes a component of hybrid construction for a motor vehicle, in particular a crossmember for the cockpit region, in which the crossmember is designed as a lightweight component with a shell-shaped basic body and with reinforcing ribs consisting of molded-on plastic. In this case, at least one duct is entirely or partially injection molded together with the reinforcing ribs in the interior of the basic body. The duct serves, for example, for conducting air of an air conditioning system. However, a component of this type leaves something to be desired. 
   Starting from this prior art, it the object of the invention to provide an improved crossmember. 
   SUMMARY OF THE INVENTION 
   The invention provides a crossmember for a motor vehicle, in particular for the cockpit region, in which at least one wall running transversely with respect to the crossmember is provided. In particular, a wall is provided at the ends of the crossmember (A-pillar connection), in the region of the connection for the airbag, steering system and tunnel strut and wherever else holders are required. 
   A passage is preferably provided between the wall and basic body. In particular, an air duct which is part of an air conditioning system can run through the passage, but also a duct for the wiping water for the headlights or the windshield, cooling water, oil, compressed air or the like, if appropriate also for the protected laying of cables, petrol lines, oil lines, compressed air lines or the like may also be provided. The air duct may be inserted or injection molded, for example. The insertion or injection molding of the air duct affords the advantage of enabling plastics which are more reasonably priced to be used, since the static is absorbed by the other elements, in particular by the basic body, the walls and optionally provided reinforcements, which are manufactured in particular from metal. 
   The wall preferably consists of a metal sheet, in particular of steel, aluminum of magnesium, and has connections at which the crossmember can be attached to an A-pillar or the like or at which other elements can be attached to the crossmember. As an alternative, other metals, in particular high-strength metals, may also be used. 
   The wall preferably forms part of the elements which are to be attached to the crossmember, such as, for example, the A-pillar connection, the steering system, the support for the scuttle, the holder for the gearshift mechanism, electronic box, glove compartment, airbag, knee bag, instrument panel, the channel strut, the pedal block and the central consoles. In this case, the walls or their functions are integrated directly in the attachment element or the wall entirely or partially takes on the functions of the attachment elements, for example forms parts of an airbag housing. In this case, the attachment elements and the walls may also, however, be of multi-part design. This enables a further reduction in weight to be achieved. 
   The crossmember, for reinforcement, preferably has ribs, rib elements and/or tension elements and/or compression elements which are attached to the basic body. In this case, the reinforcement is preferably a cast part, sintered part or forged part which is manufactured, in particular, from steel, aluminum or magnesium. The wall may, for example, also be integrated directly in the reinforcement, i.e. may be part of the reinforcement. In particular, the reinforcing elements are arranged at angle of 45° +/−10° with respect to the longitudinal direction of the crossmember if the crossmember is subject to bending and torsional loading. 
   According to one alternative embodiment for pure bending loading, the crossmember, for reinforcement, has ribs, rib elements and/or tension elements which are attached to the basic body and are arranged at angle of 0° or 90° with respect to the longitudinal direction of the crossmember. 
   According to one preferred embodiment, the rib elements have a V-shaped design and are preferably attached to one another in such a manner that they are fixed with the ends of their limbs to the basic body and with their central regions to each other. As an alternative, however, elements which correspond to a plurality of rib elements connected in such a manner may also be provided. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention is explained in detail below using a plurality of exemplary embodiments and with reference to the drawing, in which: 
       FIG. 1  shows a perspectively illustrated crossmember according to the first exemplary embodiment, 
       FIG. 2  shows an illustration of a wall in a basic body according to the first exemplary embodiment, 
       FIG. 3  shows an illustration of a variant to  FIG. 2 , 
       FIG. 4  shows an illustration of a rib element according to  FIG. 1 , 
       FIG. 5  shows an illustration of a first variant of a rib element, 
       FIG. 6  shows an illustration of a second variant of the ribbing, 
       FIG. 7  shows an illustration of a third variant of the ribbing, 
       FIG. 8  shows an illustration of part of the ribbing from  FIG. 7 , 
       FIG. 9  shows an illustration of a fourth variant of the ribbing, 
       FIG. 10  shows an illustration of a fifth variant of the ribbing, 
       FIG. 11  shows an illustration of a further exemplary embodiment, and 
       FIG. 12  illustrates the placement of the crossmember according to the invention in a typical, schematically shown vehicle body. 
   

   DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     FIG. 12  illustrates the placement of crossmember  1  of the invention in the cockpit region of a vehicle body  16 . 
     FIG. 1  shows a crossmember  1  according to the first exemplary embodiment, which is designed as a crossmember for a motor vehicle. The crossmember  1  has a basic body  2 , which is formed from a sheet-metal bent part, and a ribbing  3  which is joined onto this basic body  2  and is likewise manufactured from sheet-metal bent parts, referred to below as V-shaped rib elements  4 . The connection between the ribbing  3  and the basic body  2  takes place, for example, by means of punch rivets. One rib element  4  is illustrated in simplified form in  FIG. 4 . The rib elements  4  are arranged in the basic body  2  in such a manner that they are fixed with the ends of their limbs to the basic body  2  and with their central regions to each other. In this case, the rib element  4  form a pattern, the individual lines of which, which are formed by the ribbing  3 , are at an angle of approx. 45° with respect to the longitudinal direction of the crossmember  1 . According to a first variant of the ribbing  3  that is illustrated in  FIG. 5 , a plurality of individual rib elements are of integral design or are designed such that they are connected fixedly to one another, thus providing relatively large rib elements  104  which, however, are joined together in a manner essentially corresponding to the rib elements  4  and the function of which corresponds to that of the rib elements  4 . 
   As is apparent in particular in  FIG. 2 , the basic body  2  has an essentially U-shaped profile, with the two ends being bent outward and forming an edge region  5 . For reinforcement of the outwardly pointing edge region  5  the ends may also first of all be bent outward and then a subregion of the ends may be bent back again, with the result that two sheet-metal layers running parallel to each other are provided in the edge region  5 . The lower region of the basic body  2  has a channel-shaped depression  10  which serves for the insertion of an air duct  11 . The V-shaped rib elements  4  have corresponding cutouts  12 , pointing toward the basic body  2 , with the result that the air duct  11  can have a circular cross section. 
   Walls  22  which are formed by metal sheets and run transversely with respect to the longitudinal direction of the basic body  2  are provided at the ends  20  of the basic body  2  and in the region of the steering-system connection  21 . One wall  22  is illustrated in simplified form in  FIGS. 2 and 3 . The walls  22  also have cutouts  23 , corresponding to the rib elements  4 , with the result that the air duct  11  can easily be inserted into the crossmember  1 . 
   Connections  24  are provided on the walls  22 . These connections  24  serve to connect the crossmember  1  to the A-pillars of the motor vehicle or to connect the steering system of the motor vehicle (cf.  FIG. 2 ). 
   As illustrated in  FIGS. 1 and 3 , a plurality of walls  22  may also be arranged parallel to one another. 
   The fastening of the rib elements  4  may take place in any desired manner, for example by means of pressure joining, welding, bonding, snap fasteners, clamping or foaming into place. 
   According to an alternative embodiment which is not illustrated in the drawing, the basic body consists of a profiled metal sheet which is formed in a U-shape and, corresponding to the first exemplary embodiment, is provided with rib elements. 
   A second exemplary embodiment is briefly described below with reference to  FIG. 6 , in which parts which are identical or act in an identical manner bear reference numbers which are higher by 200 than in the first exemplary embodiment. 
   According to this exemplary embodiment, instead of the V-shaped rib elements  4  straight rib elements  204  are provided in the crossmember  201 , said rib elements running in each case at an angle of approx. 45° transversely over the crossmember  201  and not intersecting. According to the present exemplary embodiment, the function of a wall is taken on by a rib element  204 . However, the walls may also be arranged in accordance with the first exemplary embodiment. Thus, according to the exemplary embodiment, a connection  224  is provided directly on a rib element  204  serving as a wall. 
     FIGS. 7 and 8  show a third exemplary embodiment having rib elements  304  running perpendicularly with respect to the longitudinal axis of the crossmember  301 , this arrangement being suitable in particular for pure bending loading. In this case, the rib elements  304  may also fulfill the function of the walls at the same time. 
   According to the fourth exemplary embodiment illustrated in  FIG. 9 , as the ribbing  403  for the crossmember  401 , rib elements  404  which correspond to those of the preceding exemplary embodiment are provided and, in addition, wires  404 ′ are stretched, with two wires  404 ′ intersecting. The deflection of the wires  404 ′ on the edge region  405  of the basic body  402  takes place by means of bolts  430 . As an alternative, prongs, hook-shaped elements or any other desired fastening or deflecting devices may be provided. Instead of wires, cables or other tensioning means may also be used. Furthermore, the use of pressure transmission means, for example of rods, is possible. In this case, the rib element  404  may be omitted in order, for example, to save on weight and costs. 
   The angle at which the wires  404 ′ are stretched with respect to the longitudinal direction of the crossmember  401  is approx. 45°, in particular 45+/−10°. 
   Under the wires  404 ′, in the regions to be reinforced, i.e. in particular in the regions in which connections are to be provided, walls with connections (not illustrated) are provided in accordance with the first exemplary embodiment. In this case, the walls may also protrude over the wires  404 ′. The wires  404 ′ may also be fastened, for example, in the region of the walls or to the walls. The design of the walls corresponds essentially to the design of the walls  4  of the first exemplary embodiment, with the result that, in turn, an air duct  411  can be accommodated in the crossmember  401 . The air duct  411  may, for example, be a plastic blow-molded part which is inserted before the assembly, but it may also be inserted subsequently. 
     FIG. 10  shows a further exemplary embodiment according to which the ribbing  503  is formed by rib elements  504  in the manner of a cover which is placed onto the basic body  502  and has struts which run obliquely with respect to the longitudinal direction of the crossmember  501  and have reinforced edge regions which take on the function of the ribs. In this case, walls to which elements which are to be connected to the crossmember  501  can be attached or with the aid of which the crossmember  501  can be fixed in place are not provided on the basic body  502 , since devices, i.e. connections  524 , corresponding to the walls are provided directly on the rib elements  504 . As an alternative, devices corresponding to the walls may be joined to the rib elements  504 . In principle, it is also possible to provide additional walls. The reinforced edge regions which are bent upward in  FIG. 10  may also be bent inward, which reduces the constructional space required. 
     FIG. 11  shows a further exemplary embodiment of the present invention, according to which two walls  622  are provided in the crossmember  601 , said walls being connected to each other in the longitudinal direction of the crossmember  601  in such a manner that they take on the function of a housing, in the present case the function of the airbag housing. 
   LIST OF REFERENCE NUMBERS 
   
       
         1 ,  201 ,  301 ,  401 ,  501 ,  601  Crossmember 
         2 ,  402 ;  502  Basic body 
         3 ,  403 ,  503  Ribbing 
         4 ,  104 ,  204 ,  304 ,  404 ;  504  Rib element 
         5 ,  405  Edge region 
         10  Depression 
         11  Air duct 
         12  Cutout 
         20  End 
         21  Steering-system connection 
         22 ,  622  Wall 
         23  Cutout 
         24 ,  224 ,  524  Connection 
         104  Wire 
         130  Bolt 
         404 ′ Wire