Patent Publication Number: US-2011061237-A1

Title: Tubular B-Pillar to Stamped Rocker Joint and Method of Assembling The Same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a division of U.S. application Ser. No. 11/539,766 filed Oct. 9, 2006, the disclosure of which is incorporated in its entirety by reference herein. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a B-pillar to a rocker panel joint for vehicles and a method of assembling a tubular B-pillar to a rocker panel assembly. 
     2. Background Art 
     Vehicle bodies generally include a B-pillar that is defined as the pillar located behind a front seat door that extends between a rocker panel of the vehicle and a roof. Conventional B-pillars are manufactured by assembling stamped panels that are welded together with spot welds formed by resistance welding equipment. 
     It has been proposed to form body framing components by hydro-forming tubular members to provide stronger and more durable body framing members. Hydro-formed components provide stronger structural support members that are lighter weight. However, joining a tubular B-pillar with a stamped body component presents challenges compared to joining sheet metal components together because the closed section of the tubular members makes it difficult to weld using resistance welding equipment. 
     The B-pillar must be joined to both the roof joint and the rocker joint. The B-pillar to rocker joint is critical for crash safety and noise, vibration and harshness (NVH) performance. If the B-pillar to rocker joint is not sufficiently robust, the load carrying capacity of the B-pillar for crash safety will not be fully utilized. Any weakness in the B-pillar to rocker joint may also downgrade the vehicle&#39;s torsion and bending stiffness. 
     Hydro-formed B-pillars having a tubular cross-section do not normally have flanges that may be spot welded to a stamped rocker panel assembly and the outer panel of the body. In addition, the contact area between a hydro-formed tubular member and a stamped rocker assembly is normally smaller because in the hydro-forming process a constant periphery of the tube must be maintained. 
     These and other challenges are addressed by Applicants&#39; invention as summarized below: 
     SUMMARY OF THE INVENTION 
     According to one aspect of the present invention, a pillar to rocker joint assembly is provided for a vehicle. The assembly comprises a tubular pillar having a pinched flange proximate a lower end of the pillar. A first access opening is provided on an inner side of the pillar and a second access opening is provided on an outer side of the pillar. A rocker outer panel is attached to the pillar through one of the first and second access openings and a rocker reinforcement is assembled to the pillar through the other of the first and second access openings. The side sill and rocker reinforcement are attached to each other and are both connected to the pillar. An outer panel is secured to the pillar which are in turn attached to the assembled rocker reinforcement and side sill. 
     According to other aspects of the invention as they relate to the pillar to rocker joint assembly, the cross-section of the pillar is box-shaped in the middle portion of the pillar. The cross-section of the pillar is an elongated rectangular cross-section at a lower portion of the pillar that fits between the rocker reinforcement and outer panel. The pillar is welded to itself at the pinched flange. The outer surface of the pillar is attached to the outer panel. An inner surface of the pillar is attached to the rocker reinforcement through an access hole in the side sill, an access hole in the outer surface of the pillar and an access opening in the outer panel. A bottom flange is formed by the outer panel, rocker reinforcement and side sill. Welds in portions of the bottom flange may be formed through one thickness of metal of the pillar, one thickness of metal of the rocker reinforcement and one thickness of metal of the side sill. 
     According to another aspect of the present invention, a method of making a pillar to rocker joint assembly is provided. The rocker joint assembly has a pillar, a rocker reinforcement, a side sill, and an outer body panel. The method comprises welding the pillar to the outer body panel through a first access opening in the inner wall of the pillar. The rocker reinforcement is welded to the side sill. The rocker reinforcement is welded to the pillar through an access opening in the side sill, a second access opening in the pillar that is vertically spaced from the first access opening in the pillar and an access area in the body outer panel. A bottom flange of the pillar, a bottom flange of the rocker reinforcement, and a bottom flange of the side sill are welded together. 
     According to other aspects of the method of making a pillar to rocker joint assembly, the bottom flange of the pillar is a pinched double flange that is provided adjacent the lower end of the pillar and the method further comprises welding the pinched double flange together prior to welding the pillar to the body outer panel. A single wall thickness may be removed from the pinched double flange to provide a single wall thickness of the pillar that is welded to the bottom side sill flange and the bottom rocker reinforcement flange. The weld of the pinched double flange, the bottom side sill flange and the bottom rocker reinforcement flange is formed below the location where the pinched double flange is welded together. The step of welding the rocker reinforcement to the side sill results in the formation of a tubular assembly. The pillar may be welded to an outer side of the rocker reinforcement. The side sill is welded to an inner side of the rocker reinforcement, thereby forming a joint in which the rocker reinforcement is sandwiched between the pillar and the side sill. The welding steps may be performed by a resistance welding operation. The pillar may have an elongated box cross-section in the longitudinal vehicle direction that is provided above a pinched double flange formed adjacent a lower end of the pillar. The pillar may have a substantially equilateral cross-section above the elongated box-shaped cross-section. 
     According to another aspect of the present invention, a method of making a vehicle structural support is provided. The method comprises hydro-forming a pillar having a box-shaped cross-section that is located above an elongated box section, and a pinched double flange adjacent a lower end of the pillar. A body panel is stamped and welded to the pillar. A rocker reinforcement and side sill are stamped and then welded together with the side sill being welded to an inner side of the rocker reinforcement. The pillar is welded to an outer side of the rocker reinforcement. 
     According to other aspects of the method of making a vehicle structural support, a single wall thickness may be removed from the area of the pinched double flange to provide a single wall thickness of the pillar that is welded to a side sill flange and a rocker reinforcement flange. The pillar may be welded to an outer side of the rocker reinforcement within the side sill being welded to an inner side of the rocker reinforcement thereby forming a joint in which the rocker reinforcement is sandwiched between the pillar and the side sill. The method may also further comprise removing a single wall thickness of the pillar in multiple vertically spaced locations to form an upper access hole and a lower access hole in the pillar. An inner surface of the pillar is welded to the rocker reinforcement through the upper access hole and a side sill access hole in the side sill and an access hole in the body outer panel. An outer surface of the pillar is welded to the body outer panel through the lower access hole in the inner surface of the pillar before the rocker reinforcement and side sill are assembled to the pillar. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a fragmentary side elevation view of a hydro-formed tubular B-pillar to a stamped rocker joint made according to one embodiment of the present invention; 
         FIG. 2  is a front elevation view of the hydro-formed B-pillar; 
         FIG. 3  is an inside elevation view of the hydro-formed B-pillar; 
         FIG. 4  is a cross-sectional view taken along the line  4 - 4  in  FIGS. 2 and 3 ; 
         FIG. 5  is a cross-sectional view taken along the line  5 - 5  in  FIGS. 2 and 3 ; 
         FIG. 6  is a fragmentary side elevation view of a side sill portion of the rocker assembly; 
         FIG. 7  is a side elevation view of a rocker reinforcement portion of the rocker assembly; and 
         FIG. 8  is a fragmentary transverse cross-sectional view of the B-pillar to the stamped rocker joint made according to one embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT 
     Referring to  FIG. 1 , a tubular B-pillar to stamped rocker joint assembly  10  is shown. The joint assembly  10  is used to join the B-pillar  12  to a side sill  16  and a rocker reinforcement  18 . The B-pillar  12  is welded to an outer body panel  20 . While the invention is described with reference to a B-pillar  12 , the invention is not limited to a B-pillar and it should be understood that the same general joint assembly and method of making a joint assembly for the present invention could also be applied to other structural pillars of the vehicle. 
     An upper access hole  22  is also shown in  FIG. 1  that is formed in an outer wall  24  of the B-pillar  12 . The upper access hole  22  is provided to permit welding the B-pillar  12  to the rocker reinforcement  18  as will be more fully described with reference to  FIG. 8  below. 
     Referring to  FIGS. 2 and 3 , two views of a B-pillar  12  are shown. The B-pillar extends between the roof (not shown) of a vehicle and a rocker panel assembly that is partially shown in  FIG. 1  above. The B-pillar  12  has a pinched double flange  28  on its lower end that may also be referred to as the bottom flange of the pillar. Referring specifically to  FIG. 3 , a single wall area  30  is provided on the pinched double flange  28 . The single wall area  30  of the B-pillar  12  is provided to facilitate welding the pinched double flange  28  to the side sill  16  and rocker reinforcement  18 . 
     Referring to  FIGS. 2-4 , a lower portion  32  of the B-pillar  12  is shown to be formed as an elongated box cross-section in the longitudinal vehicle direction. The lower portion  32  is provided above the pinched double flange that is located at the lower end of the B-pillar. The lower portion  32  of the B-pillar  12  has an outer wall  24  and an inner wall  38  that are joined by a front wall  42  and a back wall  44 . 
     Referring to  FIGS. 2 ,  3  and  5 , a middle portion  36  of the B-pillar  12  is shown to have a substantially equilateral cross-section that is provided above the lower portion  32 . As used herein the term “substantially equilateral cross-section” should be construed to mean a generally boxed shaped cross-section having nearly equal sides that are disposed at nearly right angles to each other. The corners of the elongated box cross-section are rounded and the walls may have non-linear areas depending upon the requirements of the vehicle design. 
     Referring to  FIG. 6 , the side sill  16  is shown secured to the B-pillar  12 . The side sill  16  includes an access hole  48  that provides access to allow welding the rocker reinforcement  18  to the B-pillar  12 . 
     Referring to  FIG. 7 , a rocker reinforcement  18  is shown. The rocker reinforcement  18  is joined to the side sill  16  and B-pillar  12  as will be more specifically described with reference to  FIG. 8  below. 
     Referring to  FIG. 8 , the joint assembly  10  is illustrated in cross-section to show how the B-pillar  12  and body outer panel are joined as a first subassembly. The side sill  16  and rocker reinforcement  18  are also joined together as a second subassembly. The two subassemblies are joined by welding the rocker reinforcement  18  to the inner wall  38  of the B-pillar  12 . A weld is formed that is accessible through an upper access hole  22  in the outer wall  24  of the B-pillar  12 , an access hole  48  formed in the side sill  16 , and an access hole  52  formed in the outer panel  20 . The outer wall  24  of the B-pillar  12  includes a single wall area  30  at the lower end of the B-pillar where it is joined to a bottom flange  58  of the side sill  16  and a bottom flange  60  of the rocker reinforcement  18 . 
     A lower access hole  50  is provided in the inner wall  38  of the B-pillar  12  to permit welding the outer wall  24  to the body outer panel  20  to form the subassembly of the B-pillar  12  and the outer body panel  20  before the B-pillar  12  is joined to the rocker reinforcement  18  as described above. 
     The side sill  16  and rocker reinforcement  18  are joined at their upper edges by welding an upper edge flange  54  of the side sill  16  to an upper edge flange  56  of the rocker reinforcement  18 . Similarly, a lower edge flange  58  of the side sill  16  is welded to a lower edge flange  60  of the rocker reinforcement  18 . The single wall area  30  of the B-pillar  12  is also welded to the bottom or lower edge flanges  58  and  60  when the subassemblies are joined together. 
     While the best mode for carrying out the invention has been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims.