Abstract:
A body panel includes a hood portion configured to extend over and across a vehicle front compartment, and two fender portions. A unitary, one-piece inner panel and a unitary, one-piece outer panel cooperate to define the hood portion and the two fender portions. The inner panel and the outer panel comprise a substantial portion of a vehicle body front end, replacing the multitude of inner panels, outer panels, and reinforcements in a prior art vehicle body. The body panel preferably functions as a load-bearing vehicle frame portion, reducing or eliminating prior art vehicle frame components. A method of manufacturing the body panel includes forming an inner panel and an outer panel using superplastic forming, quick plastic forming, or sheet hydroforming, and connecting the inner panel and the outer panel.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. application Ser. No. 10/305,379 filed on Nov. 26, 2002 entitled “Load-Bearing Body Panel Assembly for a Motor Vehicle”, which is hereby incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD  
       [0002]     This invention relates to vehicle body panels that have a hood portion and two fender portions at least partially defined by a unitary inner panel and a unitary outer panel.  
       BACKGROUND OF THE INVENTION  
       [0003]     A typical prior art vehicle body includes a hood and two fenders. The hood and two fenders are mounted to various vehicle frame members such as upper rails, a cowl bar, and an upper tie bar.  
       SUMMARY OF THE INVENTION  
       [0004]     A body panel for a vehicle is provided. The body panel has a hood portion and two fender portions. A unitary, i.e., one-piece, outer panel at least partially defines the hood portion and the two fender portions. A unitary, one-piece inner panel is operatively connected to the outer panel and further defines the hood portion and the two fender portions. The inner panel is preferably configured with sufficient strength such that the body panel does not require the use of reinforcement members.  
         [0005]     The body panel is also preferably configured to be a load-bearing vehicle frame portion, reducing or replacing prior art frame members such as upper rails and upper tie bars. The body panel would thus replace a significant number of parts, components and subcomponents found in prior art vehicle bodies with a single integrated body panel comprising the unitary inner panel and the outer panel.  
         [0006]     The elimination of frame members reduces the quantity of “hard” locations on a vehicle front end and correspondingly increases the quantity of deformable, energy-absorbing areas. The consolidation of fenders and hood into an integrated body panel eliminates the hard points formed at the seams between body panels in some prior art vehicles. The body panel also enables the placement of fastening elements such as hinges and/or latches near front hinge pillars instead of along a cowl and upper tie bar.  
         [0007]     A method of manufacturing a body panel is also provided. The method includes forming an outer panel and an inner panel using a process selected from the group consisting of sheet hydroforming, superplastic forming, and quick plastic forming, and connecting the inner panel to the outer panel. The inner panel and the outer panel each partially define a hood portion and two fender portions of the body panel.  
         [0008]     The above features and advantages, and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a schematic perspective view of a structural load-bearing body panel in accordance with the invention;  
         [0010]      FIG. 2  is a schematic perspective view of an inner panel of the body panel of  FIG. 1 ;  
         [0011]      FIG. 3  is a schematic perspective view of a vehicle frame in an attachment scenario with the body panel of  FIG. 1 ;  
         [0012]      FIG. 4  is another schematic perspective view of the vehicle frame of  FIG. 3  in an attachment scenario with the body panel of  FIG. 1 ;  
         [0013]      FIG. 5  is a schematic perspective view of an alternative vehicle frame structure in an attachment scenario with the body panel of  FIG. 1 ;  
         [0014]      FIG. 6  is a schematic perspective view of an alternative body panel configuration-pivotably mounted to yet another alternative vehicle frame structure;  
         [0015]      FIG. 7  is a schematic perspective view of the body panel of  FIG. 1  rigidly mounted to a vehicle frame; and  
         [0016]      FIG. 8  is a schematic perspective view of an alternative body panel configuration mounted to a substantially flat chassis. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0017]      FIG. 1  is a schematic depiction of a body panel assembly  20  having a hood portion  23  configured to extend generally horizontally above and over a vehicle front compartment, and fender portions  26  extending generally vertically from opposite sides of the hood portion  23 . The body panel assembly  20  is preferably configured to be a structural load-bearing vehicle frame portion which rigidly mounts to body frame members to transfer loads therebetween. However, within the scope of the claimed invention, the body panel assembly  20  need not be a structural load-bearing member.  
         [0018]     An outer panel  27  partially defines the hood portion  23  and the fender portions  26 . The outer panel  27  also defines part of the exterior surface of the body panel assembly  20  and partially defines the exterior surface of a vehicle. The outer panel  27  defines two wheel openings  28  along portions of the outer panel peripheral edge  29 . The body panel assembly  20  is preferably a preassembled unit and includes a grill  30  and headlights  31 .  
         [0019]     The outer panel  27  is fastened to an inner panel  32 , depicted schematically in  FIG. 2 . The outer panel  27  and the inner panel  32  preferably substantially continuously abut one another at their respective peripheral edges  29 ,  33 . In the context of the present invention, “continuously” means “at every point” or “in entirety.” Thus, substantially every point of the inner panel peripheral edge  33  abuts the outer panel peripheral edge  29 . In the context of the present invention, “abut” means to touch or to be closely adjacent without touching. Those skilled in the art will recognize a variety of fastening techniques that may be used to fasten the outer panel to the inner panel  32 , such as adhesive bonding, laser welding, etc. In the preferred embodiment, hemming is employed to fasten the inner panel to the outer panel. The inner panel  32  further defines the hood portion and the fender portions.  
         [0020]     The inner panel  32  serves as a structural member for the body panel assembly. The inner panel  32  is characterized by channel-shaped formations  35  configured to provide the inner panel  32  with structural integrity. Some of the formations are configured to bear or transfer loads that certain specific frame elements on a vehicle typically bear or transfer; these formations are configured to act as vehicle frame members that are an integral part of the body panel assembly. Integral frame member formations include an integral tie bar formation  38 , integral upper rail formations  41 , and an integral cowl bar formation  44 . A formation  47  in each of the fender portions is configured to improve the structural rigidity of the fender portion and for bearing loads from front hinge pillars (not shown).  
         [0021]     The integral frame member formations may be used in conjunction with a corresponding non-integral vehicle frame member to assist the non-integral frame member, or the integral frame member may entirely replace the corresponding non-integral frame member. For example, the integral upper rail formations  41  may be used with upper rails, facilitating the use of smaller, less prominent upper rails, or the integral upper rail formations may facilitate the elimination of upper rails in a vehicle body by performing the functions of upper rails. The formations  35 ,  38 ,  41 ,  44 ,  47  are preferably sufficiently configured such that the body panel assembly has suitable structural integrity and rigidity without separate reinforcement members connected to the inner panel or the outer panel. Formations  50  are configured to absorb energy in the event of a frontal impact.  
         [0022]     The inner panel  32  preferably defines holes  52  between formations  35 ,  38 ,  41 ,  44 ,  47  where material has been removed to reduce the mass of the panel. Those skilled in the art will recognize a variety of processes that may be used within the scope of the claimed invention to form the holes, including laser cutting, punching, etc.  
         [0023]     Clinch nuts  53  mounted to the inner panel  32  serve as attachment couplings configured to rigidly mount the body panel assembly  20  to load-bearing frame members on a vehicle. Those skilled in the art will recognize a variety of rigid and releasable fasteners and fastening systems that may be employed to enable the body panel assembly  20  to receive and transfer loads to and from the frame members to which it is attached.  
         [0024]     The outer panel and the inner panel are each one piece. Those skilled in the art will recognize a variety of materials that may be employed within the scope of the claimed invention to form the inner panel and the outer panel, such as metals, plastics, composites, etc. Those skilled in the art will also recognize a variety of forming techniques that may be employed within the scope of the claimed invention to form the contours of the inner panel and the outer panel, such as stamping, injection molding, etc. However, the inner panel and the outer panel are preferably formed using sheet hydroforming, quick plastic forming, or superplastic forming so that their shapes are more complex than shapes that are generally achievable with stamping. Quick plastic forming is described in U.S. Pat. No. 6,253,588, issued Jul. 3, 2001 to Rashid, et al, which is hereby incorporated by reference in its entirety. Superplastic forming is described in U.S. Pat. No. 5,974,847, issued Nov. 2, 1999 to Saunders, et al, which is hereby incorporated by reference in its entirety.  
         [0025]      FIG. 3 , wherein like reference numbers refer to like components from  FIGS. 1 and 2 , is a schematic perspective illustration of the front and partial left side of a vehicle frame  56  forming part of a vehicle. The vehicle frame  56  has a plurality of structural load-bearing body frame members, including upper rails  59 ; mid-rails  62 ; a cowl bar  65 ; an upper tie bar  68 ; front hinge pillars  71  each having a forward edge  72 ; and front wheelhouses  74  having shock towers  75 . Some of the load-bearing body-frame members partially form a front compartment  77 . A bulkhead  78  separates the front compartment  77  from a passenger space  79 .  
         [0026]     The upper rails  59  extend substantially longitudinally from the front hinge pillars  71  forward to the upper tie bar  68 , and partially define the upper extent of the front compartment  77 . The upper tie bar  68  is a cross member that extends substantially transversely and partially defines the upper and forward extent of the front compartment  77 . The cowl bar  65  is a cross member that extends substantially transversely and partially defines the upper and rearward extent of the front compartment  77 . Mid-rails  62 , also referred to as “lower rails,” extend substantially longitudinally at a lower height than the upper rails  59 . The mid-rails  62  are inboard of the upper rails  59  to accommodate wheels. Front wheelhouses  74  extend from the mid-rails  62  to the upper rails  59 . Shock towers  75  house various suspension components (not shown).  
         [0027]     The front compartment  77  may be an “engine compartment” used to house various vehicular components, including steering system components, braking system components, and powerplant components. Within the scope of the claimed invention, the vehicle may employ any powerplant, such as a conventional internal combustion engine, an electric motor, a fuel cell, a hybrid-electric system, etc.  
         [0028]     The upper rails  59 , front hinge pillars  71 , shock towers  75 , and upper tie bar  68  each include complementary attachment couplings  80  engageable with, and positioned to align with, the attachment couplings  53  on the inner panel. In the embodiment depicted, the complementary attachment couplings  80  are holes through which threaded bolts (not shown) are placed to engage the clinch nuts  53  on the body panel assembly  20 . The attachment couplings  53 ,  80  are preferably releasably engageable so that the body panel assembly  20  is removable in the event that vehicular componentry in the front compartment  77  requires repair or replacement. The vehicle frame  56  depicted includes complementary attachment couplings  80  on the cowl bar  65  which may be used with a body panel assembly having corresponding clinch nuts. However, the body panel assembly  20  preferably, as depicted, does not include clinch nuts that align with complementary attachment couplings on the cowl bar. It may be preferable for the attachment couplings on the inner panel to be strikers and for the complementary attachment couplings to be latches to facilitate installation and removal of the body panel assembly  20 .  
         [0029]     The body panel is shown in phantom  20 □ rigidly mounted with respect to each of the upper rails  59 , front hinge pillars  71 , shock towers  75 , and upper tie bar  68  such that the body panel assembly  20 , and correspondingly the inner panel and the outer panel, substantially abut the cowl  65 , a lower front cross member  84  that functions as a bumper, and rocker panels  88 . The front cross member  84  that functions as a bumper is rigidly attached to the lower rails  62  in the embodiment depicted. However, those skilled in the art will recognize that, within the scope of the claimed invention, a “bumper” may be mounted to the frame  56  via energy-absorbers so that the bumper is movable relative to the frame  56  in an impact. A movable bumper may be preferable in order to satisfy regulations governing bumper performance.  
         [0030]     The inner panel and the outer panel  27  of the body panel assembly  20  depend generally downwardly from the hood portion  23  to abut the bumper  84 . The inner panel and the outer panel extend forward of the bumper  84  to thereby conceal the bumper  84  from view from the exterior of the vehicle. The forward edges  72  of the front hinge pillars  71  substantially continuously abut the inner panel and the outer panel of the body panel assembly  20 . Each front wheel opening  28  of the vehicle is substantially entirely defined by the outer panel  27  of the body panel  20 , including substantially the entire rearward edge  89  of each wheel opening  28 .  
         [0031]     In the context of the present invention, the body panel assembly  20  is “rigidly mounted” with respect to a frame member if a connection or fastening device fastening the body panel assembly  20  to the frame member is configured to bear and transfer loads and moments between the body panel assembly  20  and the frame member irrespective of load vector. For example, the body panel assembly  20  would not be rigidly mounted to a frame member if the only locking or fastening element interjacent the body panel and the frame member is a hinge; by design, a hinge cannot support a moment, and the body panel assembly  20  could pivot relative to the frame member. Although the body panel assembly  20  is preferably rigidly mounted with respect to frame members, it is within the scope of the claimed invention to non-rigidly mount the body panel assembly with respect to frame members. For example, hinges may be employed in conjunction with at least one latch to pivotably connect the body panel assembly to the vehicle frame.  
         [0032]     The loads borne by the frame members are smaller than those of conventional vehicles because the load-bearing body panel assembly  20  distributes loads among the frame members. As a result, the frame members need not be as large or prominent as they are in the prior art. For example, the upper rails  59 , cowl bar  65 , and upper tie bar  68  each have an open section form, as opposed to a closed box form found in the prior art.  
         [0033]      FIG. 4 , wherein like reference numbers refer to like components from  FIGS. 1-3 , shows the front and partial right side of the vehicle frame  56  and body panel assembly  20 .  
         [0034]     Referring to  FIG. 5 , wherein like reference numbers refer to like components from  FIGS. 1-4 , a vehicle frame  56 ′ with an alternative frame configuration is schematically depicted. The vehicle frame  56 ′ does not have upper rails or an upper tie bar. The body panel assembly  20 ′ is rigidly mounted to the front hinge pillars  71 , shock towers  75 , and upper front mounting brackets  90  (some of the clinch nuts  53  on the body panel assembly  20 ,  20 ′ depicted in  FIGS. 2-4  are not depicted in  FIG. 5  for clarity). The body panel assembly  20 □ functions as a structural member, transferring loads between the front hinge pillars  71 , the upper front mounting brackets  90 , and the front wheelhouses  74 , and replaces an upper tie bar and upper rails found in conventional vehicles.  
         [0035]      FIG. 6 , wherein like reference numbers refer to like components from  FIGS. 1-5 , is a schematic depiction of yet another vehicle frame  56 ″ configuration and a body panel assembly  20 ″. The vehicle frame  56 ″ is characterized by the absence of an upper tie bar and upper rails. A latch  92  is mounted at each front hinge pillar  71 . The body panel assembly  20 ″ is substantially similar to the body panel assembly  20  of  FIGS. 1-5 , except that body panel assembly  20 ″ does not include clinch nuts. Rather, body panel assembly  20 ″ is mounted to the lower front cross member  84  with a pair of hinges  91  so that the body panel assembly  20 ″ is pivotable about the hinges between a closed position and an open position (shown as  20 ′″). The body panel assembly includes a striker  93  attached thereto and positioned to engage latch  92  when the body panel assembly  20 ″ is in the closed position. The body panel assembly  20 ″ is operatively connected to the vehicle frame  56 ″ without the use of any fastening or locking elements at any upper frame components. More specifically, the body panel assembly  20 ″ is operatively connected to the vehicle frame  56 ″ at points other than on a cowl bar, upper tie bar or other upper cross member, and upper rails. Rigid fasteners may similarly be employed at the lower front cross member  84  and front hinge pillars  71  to rigidly fasten the body panel assembly  20 ″ to the vehicle frame  56 ″.  
         [0036]      FIG. 7 , wherein like reference numbers refer to like components from  FIGS. 1-6 , is a schematic depiction of the vehicle frame  56  with the body panel assembly  20  rigidly mounted to frame members. The hood portion  23  extends above and across the front compartment, thereby protecting vehicular components contained therein, including a powerplant  94 . The powerplant  94  and other underhood vehicular components are preferably designed to perform for a significant amount of time without requiring repair or replacement. The powerplant  94  is preferably configured to operate without repair or replacement for the first one hundred thousand miles of vehicle travel.  
         [0037]     The body panel assembly  20  does not exhibit overslam travel because it is rigidly mounted to the vehicle frame members. Since the body panel assembly  20  is rigidly mounted to frame members, access to battery terminals for battery recharging or jump-starts, oil fill, windshield solvent fill, and powerplant coolant fill is preferably provided in a location that does not require the removal of the body panel assembly  20 . For example, access may be provided in a trunk area, or behind a removable or retractable panel in the front of the vehicle.  
         [0038]     Referring to  FIG. 8 , wherein like reference numbers refer to like components from  FIGS. 1-7 , an alternative embodiment of the body panel assembly  20 A is mounted with respect to a chassis  96 . Body panel assembly  20 A is substantially similar to the body panel assembly  20  depicted in  FIG. 1 , but has different attachment couplings. The chassis  96  is self-contained and has substantially all of the mechanical, electrical, and structural componentry necessary for a fully functional vehicle, including at least an energy conversion system, a suspension and wheels, a steering system, and a braking system. The chassis has a simplified, and preferably standardized, interface with connection components to which bodies of substantially varying design can be attached. X-by-wire technology is preferably utilized to eliminate mechanical control linkages. The chassis  96  is described in U.S. patent application Ser. No. 10/205,007, and U.S. patent application Ser. No. 10/202,998, both of which are hereby incorporated by reference in their entireties.  
         [0039]     The chassis  96  has a substantially horizontal upper chassis face  97  achieved by distributing chassis systems throughout a chassis structural frame (not shown). Load-bearing body-retention couplings  98  are engageable with complementary attachment couplings  102  on a vehicle body or vehicle body part, such as body panel assembly  20 A, and function to physically fasten the vehicle body part  20 A to the chassis  96 . In the embodiment depicted, the load-bearing body-retention couplings  98  are support brackets with bolt holes, and the complementary attachment couplings  102  are brackets with bolt holes. A bolt and nut (not shown) are used to join a load-bearing body-retention coupling  98  and a complementary attachment coupling  102 .  
         [0040]     The front compartment  77 ′ is primarily defined by the body panel assembly  20 A, and may be a portion of an occupiable passenger space if a bulkhead is not employed to close out the front compartment  77 ′.  
         [0041]     As set forth in the claims, various features shown and described in accordance with the different embodiments of the invention illustrated may be combined.  
         [0042]     While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the scope of the invention within the scope of the appended claims.