Abstract:
The vehicle body of the present invention includes a first body structure formed from a plurality of tube members and a second body structure formed from sheet metal. The plurality of tube members are loosely fastened together so as to form the first body structure. The first body structure is splayed in a predetermined direction, inserted between two sheet metal members of the second body structure and fixedly secured thereto. Since the tube members are not rigidly fastened together, the tube members are free to move relative to one another in a direction lateral to the longitudinal axis of the vehicle, thereby permitting for size variation in the second body structure. The tube members are then securely fastened together. The design of the first and second body structures facilitates a welding process wherein the welds joining the first and second body structures may be staggered and offset to further improve the rigidity and durability of the vehicle body.

Description:
BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention pertains generally to motor vehicles. More particularly, the present invention pertains to vehicle bodies. More specifically, but without restriction to the particular embodiment and/or use which is shown and described for purposes of illustration, the present invention relates to a vehicle body having a portion constructed from a hydroformed tubular material. 
     2. Discussion 
     In the field of motor vehicles, especially pick-up trucks and similar vehicles, it is highly desirable to provide a tubular body to increase the strength and durability of a vehicle. Despite their advantages, tubular bodies have generally not enjoyed widespread commercial use in vehicle designers for various reasons, including the ability to consistently manufacture tubular members of the body, the ability to consistently assemble the body and the ability to integrate conventional sheet metal fabrications (e.g., doors, fenders) to a tubular body. 
     With the advent of modern hydroforming techniques, many of the concerns regarding the consistency with which the various body members may be manufactured have been rendered moot. However, significant issues with both the ability with which the vehicle body may be assembled and the use of conventional sheet metal fabrications with such tubular body frames. 
     SUMMARY OF THE INVENTION 
     It is one object of the present invention to provide an improved vehicle body construction which provides the advantages of a tubular construction and the ability to easily integrate conventional sheet metal fabrications into the vehicle. 
     It is another object of the present invention to provide an improved vehicle body construction which provides the advantages of a tubular construction and the ability to easily integrate automotive systems such as battery trays, air cleaners and radiators into the vehicle. 
     It is a further object of the present invention to provide an assembly method for installing a first body portion constructed from tubular members to a second body portion constructed from sheet metal. 
     The vehicle body of the present invention includes a first body structure formed from sheet metal and a second body structure formed from a plurality of tube members. The plurality of tube members are loosely fastened together so as to form the second body structure. The second body structure is splayed in a predetermined direction, inserted between two sheet metal members of the second body structure and fixedly secured thereto. Since the tube members are not rigidly fastened together, the tube members are free to move relative to one another in a direction lateral to the longitudinal axis of the vehicle, thereby permitting for size variation in the first body structure. The tube members are then securely fastened together. The design of the first and second body structures facilitates a welding process wherein the welds joining the first and second body structures may be staggered and offset to further improve the rigidity and durability of the vehicle body. 
     Additional advantages and features of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a top view of a portion of a vehicle constructed in accordance with the teachings of the present invention; 
     FIG. 2 is a perspective view of a portion of the vehicle of FIG. 1; 
     FIG. 3 is an exploded perspective view of the portion of the vehicle of FIG. 1; 
     FIG. 4 is an exploded perspective view of a portion of the vehicle of FIG. 1; 
     FIG. 5 is an exploded perspective view of a portion of the vehicle of FIG. 1; 
     FIG. 6 is a perspective view of a portion of the vehicle of FIG. 1; 
     FIG. 7 is a cross-sectional view taken along the line  7 — 7  of FIG. 6; 
     FIG. 8 is a perspective view similar to that of FIG. 4 but showing the construction of the vehicle in accordance with the teachings of another preferred embodiment of the present invention; and 
     FIG. 9 is a perspective view similar to FIG. 8 but showing the construction of the vehicle in accordance with the teachings of another preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     With reference to FIGS. 1 and 2 of the drawings, a motor vehicle constructed in accordance with the teachings of the preferred embodiment of the present invention is generally identified at reference numeral  10 . As will be discussed in greater detail below, vehicle  10  includes a vehicle body  14 , a battery tray mount  16 , a battery  18 , an anti-lock brake module  20 , a radiator  22 , a radiator shroud  24 , an air cleaner  26  and wheel house linear wheel house liner  28 . 
     Vehicle body  14  includes a first body structure  30  and a second body structure  34 . First body structure  30  is formed from a sheet metal material and permits conventional sheet metal fabrications, such as dash  30   a , plenum  30   b  and floor  30   c , to be readily integrated into vehicle body  14 . The construction of first body structure  30  is very similar to conventional sheet metal bodies except in the area proximate the connection to second body structure  34 . Accordingly, only the unique portion of first body structure  30  will be discussed in detail. 
     With specific reference to FIG. 2, first body structure  30  is shown to include a pair of laterally spaced apart side panels  40   a  and  40   b . As side panels  40   a  and  40   b  are identical in construction, only side panels  40   a  will be discussed in detail. Side panel  40   a  includes an upper surface  44  adapted to receive conventional body panels (not shown), a first recessed portion  48  recessed a first distance below upper surface  44  and a second recessed portion  52  recessed a second distance below upper surface  44  which is greater than the first distance. With brief reference to FIG. 5, second recessed portion  52  is shown to extend in a longitudinal direction in a manner approximately parallel the longitudinal axis of vehicle  10 . Second recessed portion  52  is shown to include a plurality of first fastening apertures  56 . 
     Returning to FIG. 2, and with additional reference to FIGS. 3 and 4, second body structure  34  is shown to include a pair of lateral body structures  70   a ,  70   b , an upper radiator tube structure  74  and a lower radiator tube structure  78 . Lateral body structures  70   a ,  70   b  each include an upper fender rail structure  90 , a lower fender rail structure  94 , a front post structure  98 , a rear post structure  102  and a frame mount bracket  103 . Upper and lower fender rail structures  90  and  94 , front post structure  98  and upper and lower radiator tube structures  74  and  78  are formed from a mild steel tubing having, in the example illustrated, a nominal wall thickness of approximately 1.3 mm. Rear post structure  102  and frame mount bracket  103  are stamped sheet metal fabrications. 
     In the particular example illustrated, upper fender rail structure  90  includes a rearward end section  110 , an intermediate section  114  and a forward end section  118 , each of which lie in a generally horizontal plane. Rearward end section  110  is generally parallel the longitudinal axis of vehicle  10  and has a generally square cross section. A first upper securing aperture  122  is formed in the outer surface  126  of rearward end section  110  and a pair of second upper securing aperture  123  is formed in the inner surface  252  or rearward end section  110 . First and second upper securing apertures  122  and  123  will be discussed in greater detail, below. Intermediate section  114  is coupled to rearward end section  110  at a first end and to forward end section  118  at a distal end. Intermediate section  114  tapers inwardly from rearward end section  110  to forward end section  118 . Forward end section  118  is generally perpendicular to the longitudinal axis of vehicle  10  and includes a fastening aperture  130  which extends through its upper surface  134 . Fastening aperture  130  will be discussed in greater detail, below. 
     Upper fender rail structure  90  is formed from a tube having an initial length of about 50.5 inches and a diameter of about 2.5 inches. Upper fender rail structure  90  is initially processed through a pre-bending operation wherein intermediate and forward end sections  114  and  118  are positioned relative rearward end section  110 . Upper fender rail structure  90  is next processed through a hydroforming operation wherein its cross-section is changed in a predetermined manner and any holes, including first and second upper securing apertures  122  and  123  and fastening aperture  130  are pierced. Preferably, the pressure exerted on the tubing during the hydroforming operation is sufficient to alter the cross-section of the tube but not sufficient to substantially reduce the wall thickness of the tube. Upper fender rail structure  90  is then trimmed to size. 
     Lower fender rail structure  94  is shown to include a rearward end section  140 , an intermediate section  144 , and a forward end section  148 . Rearward end section  140  is generally rectangular in cross-section and includes a plurality of first lower securing apertures  152  formed in the outer surface  153  of lower fender rail structure  94  and a plurality of second lower securing apertures  154  formed in the inner surface  155  of lower fender rail structure  94 . First and second lower securing apertures  152  and  154  will be discussed in greater detail, below. Intermediate section  144  is shown to couple rearward end section  140  to forward end section  148 . Intermediate section  144  is shown to curve downwardly and then upwardly while tapering inwardly toward the longitudinal axis of vehicle  10  as lower fender rail structure  94  is traversed from rearward end section  140  to forward end section  148 . Forward end section  148  is generally perpendicular to the longitudinal axis of vehicle  10  and includes a pair of slotted fastening apertures  156  in each of its upper and lower surfaces  160  and  162  respectively. Forward end section also includes a generally open end which forms a tube insertion member  164 . The major axis of each of the slotted fastening apertures  156  is generally perpendicular to the longitudinal axis of vehicle  10 . Fastening apertures  156  will be discussed in greater detail, below. 
     Lower fender rail structure  94  is formed from a tube having an initial length of about 70 inches and a diameter of about 3.6 inches. Lower fender rail structure  94  is initially processed through a pre-bending operation and then through a pre-forming operation where intermediate section  144  and forward end section  148  are positioned relative rearward end section  140 . As compared to the process for forming upper fender rail structure  90 , an additional pre-forming operation has been found to be desirable due to the non-planar configuration of lower fender rail structure  94 . Lower fender rail structure  94  is next processed through a hydroforming operation wherein its cross-section is changed in a predetermined manner and any holes, including first and second lower securing apertures  152  and  154  and fastening apertures  156  are pierced. Preferably, the pressure exerted on the tubing during the hydroforming operation is sufficient to alter the cross-section of the tube but not sufficient to substantially reduce the wall thickness of the tube. Lower fender rail structure  94  is then trimmed to size. 
     Upper radiator tube structure  74  is shown to include a left end section  180 , an intermediate section  184  and a right end section  188 . Left and right end sections  180  and  188  each have a channel-shaped cross section with a slotted retention aperture  192 , the major axis of which extends along the longitudinal axis of upper radiator tube structure  74 . Upper radiator tube structure  74  is formed from a tube having an initial length of about 52.4 inches and a diameter of about 2.5 inches. Upper radiator tube structure  74  is initially processed through a pre-bending operation where left and right end sections  180  and  188  are pre-formed. Upper radiator tube structure  74  is next processed through a hydroforming operation wherein its cross-section is changed in a predetermined manner and any holes are pierced, including slotted retention apertures  192 . Preferably, the pressure exerted on the tubing during the hydroforming operation is sufficient to alter the cross-section of the tube but not sufficient to substantially reduce the wall thickness of the tube. Upper radiator tube structure  74  is then trimmed to size. 
     Lower radiator tube structure  78  is generally rectangular in cross-section and includes a plurality of fastener apertures  200  in the upper and lower surfaces  204  and  206  of each of its left and right end sections  208  and  210 , respectively. Lower radiator tube structure  78  also includes a plurality of slotted wind apertures  212  extending through its forward and rearward surfaces  216  and  220 , respectively. Rearward post structure  102  is generally channel shaped in cross-section. Forward post structure  98  includes an upper end section  240 , a lower end section  244  and a body portion  248 . Body portion  248  is generally rectangular in cross-section. Upper end section  240  is contoured to fit along the inner surface  252  of upper fender rail structure  90  proximate the intersection between intermediate section  114  and forward end section  118 . Lower end section  244  is generally rectangular in cross-section. Frame mount bracket  103  is generally U-shaped having a pair of legs  103   a  which a spaced apart sufficiently to permit front post structure  98  and lower fender rail structure to fit therebetween. 
     Lower radiator tube structure  78  and forward post structure  98  are formed from a tube having an initial length of about 84.4 inches and a diameter of about 3.25 inches. The tubing is processed through a hydroforming operation wherein its cross-section is changed in a predetermined manner and any holes are pierced, including the plurality of fastener apertures  200 . Preferably, the pressure exerted on the tubing during the hydroforming operation is sufficient to alter the cross-section of the tube but not sufficient to substantially reduce the wall thickness of the tube. The tubing is then severed in predetermined locations to form and trim to size the lower radiator tube structure  78  and forward and rearward post structures  98  and  102 . 
     Lateral body structures  70   a ,  70   b  are formed by inserting upper and lower fender rail structures  90  and  94  and front and rear post structures  98  and  102  into a fixture and welding the structures together, preferably through a M.I.G. welding process so as to maximize the strength of the structure while maintaining the heat-related distortion of the structure within desired limits. Clinch or RIV nuts, such as clinch nuts  269  and brackets (not shown) are fastened to lateral body structures  70   a ,  70   b  as desired to facilitate the mounting of various vehicle accessories (not shown). 
     Clinch nuts  270  are fixedly coupled to the fastening aperture  130  Clinch nuts  274  are also fixedly coupled in each of the plurality of fastener apertures  200  in lower radiator tube structure  78 . 
     The components comprising second body structure  34  are next subassembled as shown in FIG.  4 . Lateral body structures  70   a ,  70   b  are placed into an assembly fixture (not shown). The right and left ends  208  and  210  of lower radiator tube structure  78  are inserted into the insertion members  164  in the forward end sections  148  of lateral body structures  70   b  and  70   a , respectively. Upper radiator tube structure  74  is positioned on the top surface  134  of the forward sections  118  of the upper fender rail structures  90 . Fasteners  280  are placed into each of the lower fender rail structure  94  and the upper radiator tube structure  74  and rotated to engage the clinch nuts  270  and  274  in the upper fender rail structures  90  and lower radiator tube structure  78 . 
     Preferably, fasteners  280  are rotated sufficiently to draw the respective components together in a loose manner. A spin-off socket (not shown) may be employed to leave a small predetermined distance from the heads of fasteners and their corresponding components. Presently, a distance of approximately ⅛ inch (0.12 inch) is preferred. Assembly of the second body structure  34  in this manner permits second body structure  34  to be installed to first body structure  30  at one time while providing for size variation in the width of first body structure  30 . More specifically, the tube-in-tube design of the lower radiator tube structure  78  and lower fender rail structure  94  permits the lateral body structures  70   a ,  70   b  to telescope inwardly or outwardly as needed to adjust for the width of first body structure  30 . Similarly, fixing the clinch nuts  270  to upper fender rail structure  90  and engaging fasteners  280  through the slotted retention apertures  192  permits the forward sections  118  of the upper fender rail structures  90  to move along an axis perpendicular to the longitudinal axis of vehicle  10  to adjust for the width of first body structure  30 . In order to facilitate the movement of upper and lower radiator tube structures  74  and  78 , fasteners  280  are preferably engaged into clinch nuts  270  and  274  such that a clamping force of less than about 10 lbf. and preferably less than about 2 lbf. 
     After the second body structure  34  has been loosely assembled, a force is applied to lateral body structures  70   a ,  70   b  to splay the ends  284  of second body structure  34  (i.e., the ends corresponding to rearward end sections  110  and  140 ) outwardly from the longitudinal axis of vehicle  10 . Second body structure  34  is next introduced to first body structure  30  such that rearward end sections  110  and  140  are proximate the corresponding second recessed portions  52 . A force is then applied to the ends  284  of second body structure  34  to position the inner surfaces  252  and  256  of upper and lower frame rail structures  90  and  94 , respectively, against the outer surfaces  300  of side panels  40   a  and  40   b  such that each of the rearward end sections  110  and  140  are at least partially disposed in the respective second recessed portions  52 . 
     A securing means  304  is employed to fixedly couple upper and lower fender rail structures  90  and  94  to the respective side panels  40   a  and  40   b . Securing means  304  may include, for example, a conventional threaded fastener, a rivet or a weld. First upper and lower securing apertures  122  and  152  are employed to permit the inner wall of upper and lower fender rail structures  90  and  94  to be coupled to the associated side panel  40 . In the particular embodiment illustrated, spot welds are employed to fixedly couple upper and lower fender rail structures  90  and  94  to the respective side panels  40   a  and  40   b . A spot welding tool (not shown) is introduced through first upper and lower securing apertures  122  and  152 . The spot welding tool exerts a clamping force against the inner wall of upper and lower fender rail structures  90  and  94  and side panel  40  to draw these structures together. The spot welding tool then discharges electricity through side panel  40  and upper and lower fender rail structures  90  and  94  to fuse these structures together at predetermined points. The spot welding tool is thereafter removed. 
     With reference to FIGS. 6 and 7, a pair of aperture extension structures  400  are coupled to vehicle body so as to cover at least a portion of lateral body structures  70   a  and  70   b , respectively. Each aperture extension structure  400  is preferably formed from a sheet metal material and renders side panels  40   a  and  40   b  and lateral body structures  70   a ,  70   b  suitable for coupling to conventional sheet metal fabrications, such as fenders (not shown). 
     A securing means  404  is employed to fixedly couple upper and lower fender rail structures  90  and  94  to the respective aperture extensions  400 . Again, securing means  404  may include, for example, a conventional threaded fastener, a rivet or a weld. First securing apertures  56  and second lower securing apertures  154  are employed to permit the outer wall of lower fender rail structures  94  to be coupled to the associated aperture extension structure  400 . In the particular embodiment illustrated, spot welds are employed to fixedly couple lower fender rail structures  94  to the respective aperture extension structures  400 . A spot welding tool is introduced through one of the first securing apertures  56   a  and second lower securing aperture  154 . The spot welding tool exerts a clamping force against the inside surface of the outer wall of lower fender rail structures  94  and against the outer surface of aperture extension structure  400  to draw these structures together. The spot welding tool then discharges electricity through aperture extension structure  400  and lower fender rail structure  94  to fuse these structures together at predetermined points. The spot welding tool is thereafter removed. 
     Also in this particular embodiment, fasteners  405  are employed to fixedly couple upper fender rail structures  90  to their respective aperture extension structures  400 . Fasteners  405  are placed through fastener apertures  406  in each of the aperture extensions  400 . Fasteners  405  extend through their associated aperture extension  400  and threadably engage one of the clinch nuts  269  in upper fender rail structure  90 . In the particular embodiment illustrated, fasteners  405  also engage a hood hinge to secure aperture extension  400 , upper fender rail  90  and the hood hinge together. 
     FIG. 7 shows the spot welds  410  which secure the side panels  40   a  and  40   b  and upper and lower frame rail structures  90  and  94  together are spaced axially apart from the spot welds  414  securing the upper and lower frame rail structures  90  and  94  to the aperture extension structures  400 . The staggered relationship of welds  410  and  414  increases the strength and rigidity of this joint, improving the robustness of the design. 
     Returning to FIG. 1, wheel house liner  28  is employed to inhibit the vehicle wheels from slinging dirt, moisture and grime into the vehicle engine compartment when vehicle  10  is operating. Wheel house liner  28  is formed from a plastic sheet material, such as polypropylene and coupled to a lower surface  260  of lower fender rail structure  94 . Wheel house liner  28  may be formed from a series of strips or may be formed through a conventional molding process, such as blow molding or vacuum formed. As compared to conventional sheet metal shrouding, wheel house liner  28  is lightweight and highly flexible. 
     While the vehicle body of the present invention has been described thus far as being comprised of various hydroformed tube structures having square or rectangular cross sections which collectively form the front end of a vehicle body, those skilled in the art will appreciate that the invention, in its broader aspects, may be constructed somewhat differently. For example, one or more of the structures forming the second body portion may be formed from conventional tubing or channel as shown in FIG. 8 where the lower radiator tube structure  78 ′ is formed from a steel channel  420  having a generally C-shaped cross section. 
     In this arrangement, the fastener apertures  200 ′ in lower radiator tube structure  78 ′ are slotted. Lower fender rail structure  94 ′ is generally similar to lower fender rail structure  94  except that the fastening apertures  156 ′ in forward end section  148 ′ are round rather than slotted and a plurality of clinch nuts  424  are inserted into fastening apertures  156 ′ and coupled to the interior of forward end sections  148 ′ as shown. The right end section  208 ′ of lower radiator tube  78 ′ includes an insertion member  164 ′ which is slid over the forward end section  148 ′ of the lower fender rail structures  94 ′, providing a tube-in-channel structure. Fasteners  280  are then placed through fastener apertures  200 ′ and fastening apertures  156 ′ to threadably engage clinch nuts  424 . 
     In each of the previous examples, the second body structure included at least one tube insertion member to permit one tube or rail structure to fit at least partially within another tube or rail structure to provide a tube-in-tube or tube-in-channel design. As another example, the tube insertion member may be a discreet member as shown in FIG.  9 . 
     In this arrangement, the forward end sections  148 ″ of lower fender rail structure  94 ″ and the left end section  210 ″ of the lower radiator tube structure  78 ″ are illustrated to have a generally round cross section with outside diameters which are approximately equal. Fastener apertures  200 ″ and fastening apertures  156 ″ are slotted with the major axis of these slots being generally perpendicular to the longitudinal axis of vehicle  10 . 
     A coupler  450  is illustrated as being formed from a tubular material having an inside diameter which is slightly larger than the outside diameters of forward end sections  148 ″ and left and right end sections  208 ″ and  210 ″. Couplers  450  each include a plurality of fastening apertures  454  which extend through coupler  450  along an axis perpendicular to the longitudinal axis of vehicle  10 ″. The open ends of coupler  450  form a pair of laterally opposed tube insertion members  164   a″  and  164   b″.    
     A first one of the couplers  450  is operable for coupling one of the lower fender rail structures  94 ″ to the left end section  208 ″ of lower radiator tube structure  78 ″ and a second one of the couplers  450  is operable for coupling the other one of the lower fender rail structures  94 ″ to the right end section  210 ″ of lower radiator tube structure  78 ″. As the method for joining couplers  450  to the lower fender rail structures  94 ″ and lower radiator tube structure  78 ″ is similar, only the connection of coupler  450  to the right end section  210 ″ of lower radiator tube structure  78 ″ will be discussed in detail. The forward end section  148 ″ is placed in tube insertion member  164   a  and right end section  210 ″ is placed in tube insertion member  164   b . Fasteners  280  are placed through fastener apertures  200 ″ and fastening apertures  156 ″ and  454  and rotated to threadably engage nuts  460 . Those skilled in the art should readily understand that coupler  450  may also be prefastened to either lower fender rail structure  94 ″ or lower radiator tube structure  78 ″ through a conventional fastening or joining process, such as threaded fasteners, rivets, adhesives or welds. 
     While the invention has been described in the specification and illustrated in the drawings with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention as defined in the claims. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment illustrated by the drawings and described in the specification as the best mode presently contemplated for carrying out this invention, but that the invention will include any embodiments falling within the description of the appended claims.