Abstract:
Disclosed is a profiled element ( 66 ) which is designed as a hollow profiled support section and is used for fastening a bumper to longitudinal beams ( 30 ) of a vehicle. Said profiled element ( 66 ) is assigned to a longitudinal beam ( 30 ) made of steel as an insertable section for the interior ( 32 ) of the longitudinal beam ( 30 ). The final edge ( 67 ) of at least two opposite walls ( 68 ) of the insertable section of the profiled element ( 66 ), which is made of a light metal material, is attached inside an insertion member ( 70 ) which, as a separation layer, prevents adjacent surfaces that are made of light metal and iron-carbon alloys from corroding. The insertable section is inserted into the longitudinal beam ( 30 ) along with the insertion members ( 70 ).

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. National-Stage entry under 35 U.S.C. §371 based on International Application No. PCT/EP2007/003375, filed Apr. 17, 2007, which was published under PCT Article 21(2), and claims priority to German Application Nos. 102006019654.6, filed Apr. 25, 2006, and claims priority to German Application No. 102006040178.6, filed Apr. 25, 2006, which are all hereby incorporated in their entirety by reference. 
     TECHNICAL FIELD 
     The invention relates to a profiled element for fastening a bumper to longitudinal beams of a vehicle; the profiled element is embodied as a profile containing at least one side wall and two transverse walls adjoining said side wall with a hollow profile beam section which is assigned to a longitudinal beam made of steel as an insertable section for the interior space of the longitudinal beam. In addition, the invention covers a method for the installation of the profiled element. 
     BACKGROUND 
     A device in a vehicle for absorbing impact energy with a fastening beam for a bumper element on the vehicle frame can be taken from EP1 079 992 B1; that fastening beam has at least two walls running in longitudinal direction which are provided with one or several openings in order to accommodate one or several through-bolts. In the event of a collision impact or a vehicle collision the bolts are moved along predetermined lines relative to the respective energy-absorbing walls of the fastening beam and/or the vehicle frame and/or the bumper in order to enlarge those openings subject to the formation of strips. To this end, the bolts are designed so that they shear off the wall material in order to enlarge or elongate the openings in the energy-absorbing wall. 
     A bumper with the plate-like holders crossing the longitudinal axis of its longitudinal beam is described in EP0 718 158 B1 with the reference that in addition to the cross-sectional shape of the bumper the embodiment of the connection to the vehicle longitudinal beam also influences the shape retention capability of said bumper as well as its compensating capacity for the impacting deformation energy. 
     For fastening the bumper to the vehicle a multiplicity of holders are known. For example, from U.S. Pat. No. 5,080,410 or U.S. Pat. No. 4,563,028, but which are hardly able to improve the shape retention capability of a bumper upon an impact. 
     In EP0 894 675 A1 a bumper arrangement is described, wherein the holding elements of the bumper expand conically and thus its outer walls come to hug the profile wall of the bumper or merge with said profile wall of the bumper. 
     With DE 298 23 973 U1 particularly light bumpers are proposed which, in severely loaded regions, are reinforced by an additional profile. Here, the reinforcement profile can also consist of a part of a holding device for the bumper. In the latter case the side walls of the holding device expand conically and come hug the profile strips of the bumper. 
     Knowing these circumstances the inventor has made it his objective to create a bumper of the type mentioned at the outset which with low weight comprises a high degree of shape retention with adequate compensation capacity for the impacting deformation energy, i.e. an efficient energy absorption element is created. Manufacture and handling of the bumper as well as the profiled element are to be very simple and the longitudinal beam forces are to be lower as well as central. In addition, there is the object of compensating the influence of the various materials on one another; the corrosion between a profiled element or a crashbox of aluminum and a longitudinal steel beam must be prevented. In addition, the inaccuracy of the components during the joining process is to be compensated and a relatively large gap between crashbox and longitudinal beam is to be closed. 
     The teaching of the independent claim leads to the solution of this object; the subclaims state favorable further developments. The scope of the invention additionally comprises all combinations of at least two characteristics disclosed in the description, the drawing and/or the claims. With stated designation regions, values located within the mentioned limits are to be disclosed as limit values and applicable as desired. 
     SUMMARY 
     According to an embodiment of the invention, walls of the insertable section of the profiled element formed from a light metal material are arranged with its final edge in an insertion member with material preventing corrosion on adjacent surfaces of light metal alloys on the one hand and iron-carbon alloys on the other hand, and the insertable section is inserted in the longitudinal beam with the insertion members. 
     This profiled element formed of light metal material can also comprise a lesser cross section than the longitudinal beam which with at least two of its inner surfaces towards the profiled element limit a gap space each; in addition, at least two walls of the insertable section following its insertion in the longitudinal beam are embodied deformable towards the inner surfaces of said longitudinal beam and fixable to these. 
     Said insertion member with surface coatings of corrosion protection agent, for example of non-metal material, forms a protective or separating layer between the light metal or aluminum material of the profiled element on the one hand and the ferrous longitudinal beam on the other hand in order to stop corrosion damages. The surface can have been treated through alitizing, anodizing, sherardizing, chromizing, phosphatizing, enameling, lead-plating, tin-plating, copper-plating and similar coating methods or through plating, metal spraying methods, hot dipping, galvanizing and the like. Solid corrosion protection agents can be applied through gluing and wrapping of bands or films through rolling-on, pressing and the like, through applying of paints by painting on with spray-on, roll-on or brush-on compounds such as lacquers or varnishes or by melting-on of melting compounds for protective skins and fluidized bed coating. 
     It has proved to be favorable if the profiled element on at least two walls located opposite each other is provided with an insertion member enclosing a wall region each and fixes said insertion member against the wall. This insertion member is to comprise two wall plates resting against both surfaces of the wall which are connected through a groove web subject to the formation of an interior space; the width of the interior space approximately corresponds to the thickness of the wall of the profiled element and the groove web in installation position is to form a stop for the final edge of the insertable section. 
     According to a further embodiment of the invention, the outer wall plate is provided with two lateral strips which run outside the lateral edges of the inner wall plate and below the groove web comprise lugs inclined towards the interior space of the insertable section and serving as insertion aids, which are each preferably inclined at an angle of approximately 30° relative to the wall surface. 
     Advantageously, a nut fixed to the outer surface of the inner wall plate, preferably approximately at the middle of the height of said wall plate, is assigned to each lateral edge with the screw penetration for accommodating a profiled element and screw securely connecting the insertion member of which a perforation in the outer wall plate is in alignment. 
     With another embodiment of the insertion member according to an embodiment of the invention, cantilever elements, more preferably ring-like shaped collars, are molded out of the inner wall of said insertion member and inserted in the inner perforations of the wall of the insertion member in order to closely join said insertion member with the wall plate. 
     According to an embodiment of the invention, at least one lug-like strap laterally cantilevered from the outer wall of the insertion member is additionally molded to the upper edge of said outer wall of the insertion members, which in installation position rests on a corresponding lateral molding of the longitudinal beam and is capable of being joined with the latter through spot welding; the longitudinal member to this end comprises lateral termination wings at its face edge and the straps of the insertion member that can be placed on these are welded to these. 
     With a particular embodiment the wall plates of the insertion member and the walls of the profiled element hugging their insides are joined by at least one rivet as additional fixing element, which after the fastening of the screws can also be removed again. 
     It is within the scope of the invention that two parallel walls of the longitudinal beam comprising two perforations arranged in alignment with each other are each located opposite walls of a profiled element with perforations at a distance; these perforations of longitudinal beam and profiled element determine a common center axis with threaded perforations of two material strips each of which is assigned on the inside to the walls of the profiled element. These material strips are preferably of square or hexagonal cross section. 
     In this case the insertion of the profiled element or the crashbox in the longitudinal beam is simplified since the crashbox is cross-sectionally considerably smaller than the longitudinal beam; according to the invention the lateral walls and the transverse walls of the longitudinal beam with the side walls and the transverse walls of the profiled elements connecting the longitudinal beam each delimit gap spaces, i.e. spacing regions. With this profiled element an inner wall is assigned each at a distance to the two lateral walls in the interior space of the profiled element which on both ends are molded to the transverse walls and into which approximately in its longitudinal middle a groove region shortening its cross section is molded. This groove region with the following transverse wall of the profiled element is to delimit an accommodation space for one of the material strips which according to the invention lies flat against the transverse wall of the profiled element assigned to the inner surface at least in the region of the insertable section. 
     In order to be able to guide the transverse wall of the profiled element against the longitudinal beam the perforations of neighboring walls of the two system parts are penetratable by a tensile screw which engages in the thread of the thread perforation of the material strip hugging the inside and is mounted in a rotatable manner in said thread. By tightening the tensile screw towards the longitudinal beam the region of the transverse wall behind which the material strip engages is deformed until the deformed profiled element with the regions of its transverse walls deformed to the outside parallel to its center line hugs the inner surfaces of the neighboring walls of the longitudinal beam. Advantageously the two transverse walls of the profiled element then merge into the region deformed to the outside at an integrated curved region, and the inner walls in a deformed state now comprise a linear cross section. The method according to the invention for the installation of the profiled element comprises that in the thread perforation of the material strip a tension screw penetrating the profiled element and the longitudinal beam is inserted and said tension screw through rotation is pulled with the material strip to the transverse wall of the longitudinal beam; as mentioned, the transverse wall of the profiled element is placed against the transverse wall of the longitudinal beam and the cross section of the two inner walls appended to the transverse wall of the profiled element is linearly molded-out through stretching its groove region. 
     According to an embodiment of the invention, an insertion member with corrosion protection layer is thus attached to the crashbox which prevents that the steel longitudinal beam and the crashbox come into contact. The insertion member of steel plate is embodied with a bevel towards the end which during the joining process facilitates the insertion of the crashbox in the longitudinal beam. The crashbox wall is enclosed by steel plate. On its inner side at least one nut is fastened. When the crashbox is screwed tight the outer wall of the aluminum profile is pulled against the longitudinal beam. The bent aluminum webs are stretched and the joining gap between crashbox and longitudinal beam is closed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention will hereinafter be described in conjunction with the following drawing figures, wherein like numerals denote like elements, and 
         FIG. 1  is the top view of a bumper with holders according to the state of the art embodied differently on both ends of the bumper for connection to a longitudinal beam; 
         FIG. 2  is an inclined view of a part of the bumper with holder enlarged compared with  FIG. 1 ; 
         FIG. 3  and  FIG. 4  are a cross section through a longitudinal beam with profiled element as holder inserted in said longitudinal beam or a partial longitudinal section thereto; 
         FIG. 5  and  FIG. 6  are a cross section through the longitudinal beam after the change of the profiled member inserted as holder or the part longitudinal section thereto; 
         FIG. 7  is a sketch of a partially reproduced longitudinal beam with profiled member arranged at a distance and comprising insertion aids; 
         FIG. 8  is an inclined view of a pair of insertion aids; 
         FIG. 9  is the details of  FIG. 7  following the assembly; 
         FIG. 10  is a representation of another embodiment of a longitudinal beam corresponding to  FIG. 9  with profiled element arranged therein comprising insertion aids; and 
         FIG. 11  is an enlarged detail of a further embodiment of an insertion aid. 
     
    
    
     DETAILED DESCRIPTION 
     The following detailed description is merely exemplary in nature and is not intended to limit application and uses. Furthermore, there is no intention to be bound by any theory presented in the preceding background or summary or the following detailed description. 
     A bumper  10  extruded from an aluminum alloy for a passenger car which is not reproduced for the sake of clarity according to  FIG. 1  comprises a box-shaped hollow profile  12  with two profile walls  14 ,  16  running at a distance a to each other, which are connected by two transverse or flank walls  18 . The hollow profile  12  is assigned to a transverse plane E, running at a right angle to the vehicle longitudinal axis indicated at A, and on both sides of the vehicle longitudinal axis A here forming a symmetry plane evenly curved towards said transverse plane E; towards the latter the hollow profile  12  in the longitudinal axis A located in the curvature zenith determines a curvature dimension k. In installation position the outer profile wall  14  facing away from the transverse plane E forms a shock forces absorbing outer or compression belt the other, inner, profile wall  14 , an inner or tension belt. 
     Here, the bumper  10  is assigned to a pair of vehicle longitudinal members  30  of rectangular cross section molded of steel, which run on both sides parallel to the vehicle longitudinal axis A. These in turn are composed of two parallel side walls  34  and transverse walls  36  connecting these, which delimit an interior space  32  of the vehicle longitudinal beam  30 . 
     Near the right face edge  20  of the hollow profile  12  on the right-hand side in  FIG. 1  a tubular deformation element  40  of a profile piece is indicated, which on one end is attached to the inner profile wall  16  and on the other end is assigned to the vehicle longitudinal beam  30  with an insertable section  43 . The deformation element  40  also designated crashbox is likewise manufactured from a profiled element extruded from light metal and at the end facing the bumper  10  is beveled transversely to the center line M of the deformation element  40 ; the beveled edge  44  of the profiled element  40  so created determines an angle w of approximately 10° with the transverse plane E. 
     Another embodiment of the connection of the hollow profile  12  to the vehicle longitudinal member  30  is sketched on the left end in  FIG. 1  of the bumper  10  and shown in  FIG. 2 . It becomes clear here that the profile wall  14  which serves as outer belt, in itself embodied wave-like in terms of cross section, engages over both transverse or flank walls  18  with wing-like wall sections as edge strips  15 ,  15   t . From  FIG. 2  it is also evident that the side wall  34  of the vehicle longitudinal beam  30  likewise protrudes over the outer surface of the joined-on transverse wall  36  with an edge strip  35 . Otherwise, the second side wall  34  is not drawn in here for the sake of clarity, its fastening region is emphasized hatched. 
     In the profile interior space  22  of the hollow profile  12  a transverse wall  24 , directed parallel to the profile walls  14 ,  16 , each with a middle wall  26  running between said transverse wall and the profile walls  14 ,  16  is provided in one piece with the profile walls  14 ,  16  and the flank walls  18  connecting said profile walls. These middle walls  26  are noticeably offset vertically and laterally relative to each other. 
     The connection of the hollow profile  12  to the vehicle longitudinal beam  30  is established here through a holding link  46  in turn embodied of an extruded aluminum alloy hollow profile of width b of for example 55 mm and the height h of 75 mm. This holding link the insertable section  48  of said holding link assigned to and screwed into the vehicle longitudinal beam  30  of the profile height e and its face edge  31  of approximately rectangular cross section, of two parallel side walls  49  and transverse walls  50  of the hollow profile of the holder  46  joining these, is followed by a curved section  52 ; the in  FIG. 2  right side wall  49  is curved outward, that is here from the longitudinal axis M 1  of the insertable section  48  to the right, and the other side wall  49  endwards guided against the former so that both side walls  49  rest on top of each other and each of the two transverse walls  50  is folded approximately in its longitudinal center. The inner curvature contour runs in accordance with the outer surface of the inner profile wall  16  of the hollow profile  12 , i.e., it encloses the mentioned angle w with a parallel line to the transverse plane E. 
     The double-layer legs  54  of the groove-like curved section  52  so created are penetrated by screws  56  or similar connecting elements in the region of perforations—not evident in the drawing, which additionally engage in perforations of the flank walls  18  on the bumper side. Corresponding perforations for connecting elements  56   a  are provided in the insertable section  48  of the holding link  46 . These connecting elements  56   a  are mounted in perforations  38  in the vehicle longitudinal beam  30 . 
     A profiled element or a crashbox  42   a  substantially of rectangular cross section of two side walls  45   a  and two transverse walls  47   a  of the wall lengths c,f connecting these is inserted in the longitudinal beam  30  of FIGS.  3 , 4 . The transitions of the side walls  45   a  to the transverse walls  47   a  form corner regions  45   e  curved in the form of pitch circles. 
     To simplify the insertion process, the side walls  45   a ,  47   a  each run at a distance g to the neighboring interior space surface  28  of the side walls  34  as well as the transverse walls  36  of the longitudinal beam  30  subject to the formation of gap spaces  41  and  41   q.    
     In the profiled element  42   a  an inner wall  51   a  is set in front on the inside of each side wall  45   a  which on both ends is molded onto the transverse walls  47   a  and at a distance to these offers a groove-like cross section. On each molded-on region is located a mounting space  55 , determined by the groove region  53  of the inner wall  51 , for a material strip  60  of hexagonal solid cross section mounted therein. The latter is equipped with a thread perforation  58  which is in alignment with a perforation  57  of the neighboring transverse wall  47   a  and the perforation  38  in the longitudinal beam  30 . 
     In  FIG. 4 , the centerline M of the profiled element  42   a  is in alignment with the longitudinal axis B of the surrounding longitudinal member  30 . The transverse walls  47   a  of the profiled element  42   a  positioned at said distance g to the inner surfaces  28  of the longitudinal member  30  run noticeably parallel to the axis. The lined-up perforations  38 ,  57 ,  58  of the one system side with the perforations  58 ,  57 ,  38  of the other system side determine a common center axis Q and accommodate a tensile screw  56   b  indicated in  FIG. 4  each, which towards the end is screwed together with the thread  59  of the thread perforation  58  and subject to deformation of the profiled element  42   a  pulls the transverse wall  47   a  of said profiled element including the material strip  60  against the neighboring side wall  34  of the longitudinal beam  30 . The profiled element  42  sketched in  FIG. 5 ,  6  is created through this deformation. 
     This profiled element  42  in FIGS.  5 , 6 , thanks to the bending process that has taken place, instead of those bent inner walls  51   a  of  FIG. 3  towards the side walls  45  to the center axis Q, comprises inner walls  51  parallel to the axis so that the regions  47  of the transverse walls raised by this directly rest against the inner surfaces  28  of the longitudinal member  30  here and their outer distance C 1  approximately corresponds to the width of the profiled element  42 , which according to  FIG. 6 , thanks to a curved region  47   k , is reduced to the wall length c mentioned in  FIG. 3 . Thus is created within the longitudinal beam  30 , an insertable section  62  of axial length z hugging said longitudinal beam on both sides. The two side walls  45  which are parallel to the center axis Q which merge with corner regions  45   g , which are more stretched compared with  FIG. 3 , to form the adjoining transverse walls  47 , maintain the gap distance g to the inner surface  28  of the longitudinal member  30 . 
     A particular construction is evident in  FIGS. 7 ,  8 . Since longitudinal beam  30  and profiled elements have to be automatically joined and spot-welded in the body in white construction, the following problems might arise among others.
         a) Inaccuracy of the component dimensioning during the joining process has to be compensated;   b) Corrosion must be prevented between the crashbox of aluminum material and the steel longitudinal beam;   c) The profiled element formed from an aluminum alloy and the longitudinal beam have to be joined by spot welding; and/or   d) The large gap between profile wall and longitudinal member has to be closed.       

     In order to create a solution here an insertion member  70  of steel plate with corrosion protection layer, a protective paint or a foil—is provided on the profiled element or the rectangular crashbox  66  of  FIG. 7 ; the latter prevents that the steel longitudinal beam  30  and the aluminum material of the parallel crashbox walls  68 , joined by transverse walls  69 , come into contact. 
     As is especially evident from  FIG. 8  the insertion member  70  has a cross sectionally U-shaped body of two parallel wall plates  72 ,  72   i , which are connected by a lower groove web  74 , which runs transversely to the center line M in installation position, and delimit an interior space  80 . Its width approximately corresponds to the thickness i of the wall  68  of the crashbox  66 . 
     The outer wall plate  72  contains two lateral strips  76  which are parallel to each other, which run outside the lateral edges  86  of the inner wall plate  72   i  as well as are inclined endwards to said wall plate and comprise lugs  78  which protrude over the groove molding  74 . Here, the inclination angle t between the lug  78  and the wall surface of the wall plate  72  measures approximately 30°. These lugs  78  facilitate the insertion of the crashbox  66  mounted in the interior space  80  of the insertion member  70  in the longitudinal beam  30 , i.e., its parallel walls  68  are each enclosed by the steel plate. 
     From the upper edge  82  of the outer wall plate  72  there protrudes a way to the outside a lug-like strap  84  molded on to said wall plate and on the inner wall plate  72   i  two nuts ( 88 ) are fixed at half height h 1  each assigned to one of its lateral edges  86 . Its central screw perforation  89  is aligned with a perforation  73  in the outer wall plate  72 . 
     The crashbox  66  is lowered coaxially into the longitudinal beam  30  with the end region serving as insertable section  62   a  of axial length z; the crashbox  66  serves as insertion aid while the four lugs  78  of the insertion member  70  constitute additional insertion aids. 
     In order to guarantee a fixed connection between crashbox  66  and longitudinal beam  30  the insertion member  70  and the crashbox  66  must also be joined through a fixed connection. To this end, the latter is provided with screws  64  protruding into the nuts  88 . This unit is then pushed into the longitudinal beam  30  and spot-welded to the latter, i.e., the straps  84  are joined with lateral termination wings  29  of the longitudinal beams  30  through spot-welding. The screws  64  are now actuated which pull the outer wall plate  72  of the insertion member  70  against the longitudinal beam  30 . The bent webs of aluminum material are stretched and the joining gap between crashbox  66  and longitudinal beam  30  is closed. 
     Before screwing the crashbox  66  to the longitudinal beam  30 , the vehicle body is coated with substrate system KTL and painted. 
       FIG. 4  is a sketch of a further embodiment of the connection of an insertion member  70  with the crashbox  66 . This insertion member  70  is connected with the wall  68  of the crashbox  66  by means of a metal rivet  90  as fixing aid and can additionally be fixed with screws  64 ; its nuts  88  are visible at a lateral distance to the rivet  90 . 
     The wall  68  of the profiled element  66   a  of  FIG. 11  is provided with perforations  92  of diameter d near its end edge  67 , in each of which a shaped collar  94  as cantilever element of the inner wall plate  72   i  of the hugging insertion member  70   a  is pressed. That shaped collar  94  is created through a punching process and results in a permanent fixation. 
     While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.