Patent Publication Number: US-2002005621-A1

Title: Control suspension arm for a motor vehicle

Description:
CROSS-REFERENCES TO RELATED APPLICATIONS  
     [0001] This application claims the priority of German Utility Model Application, Serial No. 200 09695.8, filed May 31, 2000, the subject matter of which is incorporated herein by reference. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] The present invention relates, in general, to a control suspension arm for a motor vehicle.  
       [0003] Structural steel is typically used to date for making suspension components in the automobile industry. Apart from their costs and weight, structural steel forms a compromise between malleability and yield strength of steel, because an increase in yield strength is normally accompanied by a decrease in malleability of the steel.  
       [0004] Control arms have been typically configured as hollow steel structures in order to reconcile a higher demand on the suspension components with the limitations of installation space and/or desired weight reduction. Hereby, pressed parts, pipes or other profiled rods have been used, sometimes also in combination. Compared to massive structures, the use of hollow structures exhibits significantly better behavior under tensile stress and torsional stress while at the same time permits a weight reduction. However, such types of control arms oftentimes show a very critical buckling behavior, in particular when exposed to buckling loads in several directions.  
       [0005] It would therefore be desirable and advantageous to provide an improved control arm as suspension component for a motor vehicle, which obviates prior art shortcomings and exhibits significantly improved buckling resistance while yet exhibiting a slight weight and allowing installation in limited spaces.  
       SUMMARY OF THE INVENTION  
       [0006] According to one aspect of the present invention, a control arm as suspension component for a motor vehicle, includes a hollow steel structure of steel sheets which are at least partially pressed and welded together, and a reinforcing sheet provided in a predetermined area of the steel structure for increasing a resistance against buckling.  
       [0007] Through the provision of at least partially pressed steel sheets of a configuration that can be suited to the respective function of a control arm, it is possible to improved the resistance against buckling by providing the hollow structure with an inner reinforcing sheet at those areas which are exposed to particular high degree of buckling loads. The reinforcing sheet is hereby disposed in a plane in which the buckling loads are encountered. Without appreciably increasing the weight and without restricting the available installation space in the suspension system, a control arm according to the invention can thus be subjected to a significantly higher degree of buckling loads.  
       [0008] According to another feature of the present invention, the control arm may be formed by a U-shaped troughed shell formed having a base and legs which extend from the base and terminate in free ends which are interconnected by a transverse sheet or a complementary U-shaped sheet, having opposite ends which are welded to the free ends of the shell, thereby bounding an interior space, wherein the reinforcing sheet is welded in the interior space between the legs. A higher twist stiffness and rigidity may be realized by forming crease-like depressions in the base or also in the legs of the U-shaped shell. The reinforcing sheets is welded to the legs of the shell before attachment of the transverse sheet of complementary sheet, and, like the transverse sheet or the web of the complementary sheet that closes the shell, may have a flat configuration, optionally with crease-like depressions.  
       [0009] Through integration of such reinforcement, the weight of a control arm according to the present invention can be reduced by up to about 15%, and the acceptable buckling loads can be increased by at least 15%.  
       [0010] According to another feature of the present invention, a control arm may be configured as a transverse control arm of substantial L-shape, with substantially two straight legs which are interconnected by a central curved length section. This length section is oftentimes in danger of buckling because this area serves as attachment of a rubber bearing. Therefore, the reinforcing sheet is suitably disposed in the area of the length section and welded thereto. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWING  
     [0011] Other features and advantages of the present invention will be more readily apparent upon reading the following description of preferred exemplified embodiments of the invention with reference to the accompanying drawing, in which:  
     [0012]FIG. 1 is a schematic plan view of a transverse control arm as suspension component for a motor vehicle in accordance with the present invention;  
     [0013]FIG. 2 is a view of the control arm in the direction of arrow II of FIG. 1;  
     [0014]FIG. 3 is a sectional view of the control arm, taken along the line III-III in FIG. 1 in the direction of arrow III a;    
     [0015]FIG. 4 is a sectional view of the control arm, taken along the line IV-IV in FIG. 1 in the direction of arrow IV a;  and  
     [0016]FIG. 5 is a sectional view of another embodiment of a control arm according to the present invention. 
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS  
     [0017] Throughout all the Figures, same or corresponding elements are generally indicated by same reference numerals.  
     [0018] Turning now to the drawing, and in particular to FIGS. 1 and 2, there are shown schematic illustrations of a control arm in the form of a transverse control arm, generally designated by reference numeral  1 , for use as a suspension component for a motor vehicle in accordance with the present invention. The control arm  1  is formed as hollow steel structure and exhibits a substantially L-shaped configuration with two legs  2 ,  3  and an arched length section  4  between the legs  2 ,  3 . At its length-section-distal end, the leg  2  has a receptacle  5  for attachment of a, not shown, ball-and-socket joint, whereas the leg  3  has a length-section-distal end formed with a receptacle  6  for a, not shown, rubber bearing. Projecting the outer periphery of the curved length section  4  is an extension  7  for attachment of a rubber bearing  8 , shown only schematically.  
     [0019] As shown in FIG. 3 and  4 , the control arm  1  is comprised between the terminal receptacles  5 ,  6  of a U-shaped shell  9 , which has opposite legs  11  interconnected by a base  13 , and a flat transverse sheet  12  which extends between the legs  11  of the shell  9  and is welded to the free ends  10  of the legs  11  to thereby define an interior space  15 . The base  13  of the shell  9  is formed with a longitudinal crease  14 .  
     [0020] As shown in particular in FIG. 4, the control arm  1  is reinforced in the curved central length section  4  by a reinforcing sheet  16  which extends across the interior space  15  in a region between the base  13  of the shell  9  and the transverse sheet  12 , and is welded at its ends to the legs  11 . The reinforcing sheet  16  is attached to the legs  11  of the shell  9  before welding the transverse sheet  12 . As shown in FIG. 1, the reinforcing sheet  16  is provided at its end faces with semi-round recesses  17 .  
     [0021]FIG. 5 shows another embodiment of a control arm  1 . Parts corresponding with those in FIGS.  1  to  4  are denoted by identical reference numerals and not explained again. In this embodiment, provision is made for a complementary U-shaped shell  18 , instead of a transverse sheet  12 , for connecting the free ends  10  of the legs  11 .  
     [0022] While the invention has been illustrated and described as embodied in a control suspension arm for a motor vehicle, it is not intended to be limited to the details shown since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.  
     [0023] What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims: