Abstract:
A vehicle hood for achieving generally predetermined deformation in an event of a front impact. The hood may include an outer panel including at least one raised section along rear and side edges of the hood for thereby defining a reverse power dome. An inner panel may be attached to the outer panel and include at least two laterally extending beams each of which extend substantially across a width of the hood respectively adjacent front and the rear edges. At least one crush initiator may be disposed adjacent each of the laterally extending beams for enabling generally predetermined deformation of the hood in the event of a front impact.

Description:
BACKGROUND OF INVENTION  
       [0001]     a. Field of Invention  
         [0002]     The invention relates generally to vehicle structural design, and, more particularly, to a vehicle hood design for permitting generally predetermined hood deformation during a front impact event.  
         [0003]     b. Description of Related Art  
         [0004]     The front body of a vehicle generally includes a frame, a front bumper system, body panels, and a hood mounted to the body structure for allowing access to the engine compartment. During a front impact event, amongst other components, the front bumper system, body panels and hood are each designed to absorb a predetermined percentage of the impact, which is generally in direct correlation with the deformation characteristics of such components. Thus, the design of the front body plays an important role in the absorption and distribution of forces generated during a front impact event.  
         [0005]     While hoods normally include a smooth upper (i.e. exposed) surface, some existing hood designs include a variety of contours on the visible hood side for primarily providing a desired aesthetic appearance. Such contours are generally provided on a hood outer panel which is welded or otherwise attached to an inner panel including a variety of structural beams for allowing predetermined hood deformation, as well as for providing stiffness to the hood structure. Such contours on the outer panel however also affect the hood deformation characteristics during a front impact event.  
         [0006]     For example, referring to  FIG. 1  ( a ), an exemplary hood design is illustrated and includes a hood  10  having an outer panel  12 . As can be seen in  FIG. 1 ( a ), the outer panel includes a generally smooth outer surface. However, referring to  FIG. 2 ( a ), as discussed in detail below, a hood design according to the present invention includes a pair of raised longitudinal sections  14  equally spaced from the centerline of the vehicle (not shown). The raised sections each intersect with an equally raised section  16  that runs along the rear (lateral) edge  18  of the hood. This design creates a “reverse power dome” in center portion  20  of the outer panel, thus providing the hood with a desirable aesthetic appearance.  
         [0007]     As shown in  FIG. 1  ( b ), in order to prevent hood windshield intrusion during a front impact event, for the hood structure of  FIG. 1  ( a ) which includes a smooth outer panel surface, it is known to provide a single set of crush initiators  22  (or a single crush initiator  22  as shown in  FIG. 1 ( a )) on inner panel  24  generally centrally along the hood longitudinal direction. During a front impact event, this type of hood structure results in “A” shaped deformation of the hood (when viewed from the side of the deformed hood), which for conventional hood designs such as the design of  FIG. 1 ( a ), provides acceptable deformation characteristics. However, for a hood which includes the reverse power dome feature of  FIG. 2 ( a ), as well as other similar contours on the hood outer panel, during a front impact, the raised sections  14  and  16  may act as beams to potentially intrude into a windshield during the front impact event. Moreover, the reverse power dome feature has a natural tendency to buckle in a downward direction toward the vehicle engine (not shown), which is also undesirable.  
         [0008]     It would therefore be of benefit to provide a vehicle hood structure which allows for the inclusion of a variety of contours on the hood outer panel, such as the noted reverse power dome feature, without affecting the deformation characteristics of the hood. It would also be of benefit to provide a hood structure capable of predetermined deformation during a front impact event, with the hood structure meeting existing automotive hood deformation requirements, without significantly increasing the design, tooling and manufacturing costs for such structural components.  
       SUMMARY OF INVENTION  
       [0009]     The invention solves the problems and overcomes the drawbacks and deficiencies of prior art vehicle hood structure designs by providing a hood structure which is capable of predetermined deformation, generally regardless of the type of contours placed on the exterior hood panel.  
         [0010]     Thus an exemplary aspect of the present invention is to provide a hood structure which is capable of hood deformation without intrusion into a vehicle windshield area.  
         [0011]     Another exemplary aspect of the present invention is to provide a hood structure which meets or exceeds existing frontal impact hood deformation requirements.  
         [0012]     The invention achieves the aforementioned exemplary aspects by providing a vehicle hood for achieving generally predetermined deformation in an event of a front impact. The hood may include an outer panel including at least one raised section along rear and side edges of the hood for thereby defining a reverse power dome. An inner panel may be attached to the outer panel and include at least two laterally extending beams each of which extend substantially across a width of the hood respectively adjacent front and the rear edges. At least one crush initiator may be disposed adjacent each of the laterally extending beams for enabling generally predetermined deformation of the hood in the event of a front impact.  
         [0013]     For the vehicle hood described above, the reverse power dome may be formed by a raised lateral section provided adjacent the rear edge and a pair of raised longitudinal sections each respectively provided adjacent the side edges of the hood. The inner panel may further include at least one longitudinally extending beam disposed between the crush initiators adjacent the side edges of the hood. Further, the inner panel may include at least one laterally extending beam disposed between the crush initiators, generally centrally on the inner panel. The laterally extending beam may include tapered edges, and may also include hood mastic adhesive applied to the tapered edges for adding stiffness to the hood. At least one of the crush initiators may extend substantially across the width of the hood, and may include a concave profile. The vehicle hood may also include at least one transversely extending beam disposed adjacent at least one of the crush initiators for providing stiffness to the hood.  
         [0014]     The invention also provides a vehicle hood for achieving generally predetermined deformation in an event of a front impact. The hood may include an outer panel, and an inner panel attached to the outer panel and including at least two laterally extending beams each of which extend at least partially across a width of the hood respectively adjacent front and rear edges of the hood. At least one crush initiator may be disposed adjacent each of the laterally extending beams for enabling generally predetermined deformation of the hood in the event of a front impact.  
         [0015]     For the vehicle hood described above, the outer panel may include at least one raised section along side edges and the rear edge of the hood for thereby defining a reverse power dome. The reverse power dome may be formed by a raised lateral section provided adjacent the rear edge and a pair of raised longitudinal sections each respectively provided adjacent the side edges of the hood. The inner panel may further include at least one longitudinally extending beam disposed between the crush initiators adjacent side edges of the hood. Further, the inner panel may include at least one laterally extending beam disposed between the crush initiators, generally centrally on the inner panel. The laterally extending beam may include tapered edges, and hood mastic adhesive may be applied to the tapered edges for adding stiffness to the hood. At least one of the crush initiators may extend substantially across the width of the hood, and include a concave profile. The vehicle hood may further include at least one transversely extending beam disposed adjacent at least one of the crush initiators for providing stiffness to the hood.  
         [0016]     The invention yet further provides a vehicle including a hood for achieving generally predetermined deformation in an event of a front impact. The hood may include an outer panel, and an inner panel attached to the outer panel and including at least two laterally extending beams each of which extend at least partially across a width of the hood respectively adjacent front and rear edges of the hood. At least one crush initiator may be disposed adjacent each of the laterally extending beams for enabling generally predetermined deformation of the hood in the event of a front impact.  
         [0017]     Additional features, advantages, and embodiments of the invention may be set forth or apparent from consideration of the following detailed description, drawings, and claims. Moreover, it is to be understood that both the foregoing summary of the invention and the following detailed description are exemplary and intended to provide further explanation without limiting the scope of the invention as claimed. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0018]     The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate preferred embodiments of the invention and together with the detail description serve to explain the principles of the invention. In the drawings:  
         [0019]      FIG. 1 ( a ) is an isometric view of a related-art hood structure design, including a generally smooth hood outer panel;  
         [0020]      FIG. 1 ( b ) is a bottom view of the hood structure of  FIG. 1 ( a );  
         [0021]      FIG. 2 ( a ) is an isometric view of a hood structure design according to the present invention, illustrating a hood outer panel;  
         [0022]      FIG. 2 ( b ) is an isometric view of a hood structure design according to the present invention, illustrating a hood inner panel;  
         [0023]      FIG. 3  is a top view of the hood structure design of  FIG. 2 ( a );  
         [0024]      FIG. 4  is a bottom view of the hood structure design of  FIG. 2 ( a );  
         [0025]      FIG. 5  is a cross-sectional view of an exemplary structural beam for the hood structure design of  FIG. 2 ( a ), taken substantially along line  5 - 5  in  FIG. 3 ;  
         [0026]      FIG. 6  is a cross-sectional view of an exemplary crush initiator for the hood structure design of  FIG. 2 ( a ), taken substantially along line  6 - 6  in  FIG. 3 ; and  
         [0027]      FIG. 7  is a view illustrating the exemplary deformation characteristics of the hood structure design of  FIG. 2 ( a ), as a result of a front impact event. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0028]     Referring now to the drawings wherein like reference numerals designate corresponding parts throughout the several views,  FIGS. 2-7  illustrate a hood structure design according to the present invention, generally designated “hood structure  100 .” 
         [0029]     Referring to  FIGS. 2-6 , hood structure  100  may generally include an outer panel  101  including a front edge  102 , a rear edge  104  and longitudinal edges  106 ,  108 . Front edge  102  may be deflected downward as shown for providing an aerodynamic fit with the front grill (not shown) of a vehicle having hood  100  mounted thereon. Longitudinal edges  106 ,  108  may each respectively include raised longitudinal sections  110 ,  112  which intersect with raised lateral section  114  provided adjacent rear edge  104 . In this manner, the area between sections  110 ,  112  and  114  may form a reverse power dome for providing a desired aesthetic outer appearance of the hood. While in the embodiment illustrated, the area between sections  110 ,  112  and  114  is illustrated as being generally coplanar with longitudinal edges  106 ,  108 , it should be noted that this area may be likewise formed at a higher or lower elevation to edges  106 ,  108  to essentially form a structure on the outer panel which affects the hood deformation characteristics.  
         [0030]     Referring next to FIGS.  2 ( b ) and  4 , hood  100  may include an inner panel  116  attached to outer panel  101 , with the inner panel including a front beam  118  substantially spanning the entire width of the hood for providing rigidity to the hood structure. Beam  118  may be disposed adjacent front edge  102 . Likewise, a rear beam  120  may be provided adjacent rear edge  104  and substantially span the entire width of the hood. The structure of inner panel  116 , as well as front and rear beams  118  and  120 , respectively, may be contoured as shown for providing access to various components (i.e. latches, hinges etc.) for hood operation. Further, beams  118 ,  120  may be formed to include a substantially rectangular cross-section, and may be formed by stamping inner panel  116  or otherwise forming panel  116  as is known in the art.  
         [0031]     Referring to FIGS.  2 ( b ) and  4 , beams  118  and  120  may each respectively include adjacently disposed sets of crush initiators  122 ,  124 , which as shown in  FIG. 6 , may include a concave profile in the direction of outer panel  101 . As shown in FIGS.  2 ( b ) and  4 , crush initiator  122  may be disposed adjacent beam  118  on the side opposite to edge  102  (i.e. behind beam  118  in the forward to aft vehicle direction) for assisting with the management of energy transfer during a front impact event. Likewise, crush initiator  124  may be disposed adjacent beam  120  on the side opposite to edge  104  (i.e. in front of beam  1   20  in the forward to aft vehicle direction), for achieving proper buckling of the hood structure. In this manner, crush initiators  122 ,  124  may provide for predetermined deformation of hood structure  100 , as discussed in detail below. As illustrated, crush initiators  122 ,  124  may generally span the entire lateral width of hood structure  100 , or alternatively, crush initiators  122 ,  124  may only be formed adjacent the longitudinal edges  106 ,  108  of the hood. For example, for the embodiment illustrated, crush initiator  122  may include sub-section  122 ( a )-( d ), and likewise, crush initiator  124  may include sub-sections  124 ( a )-( d ), for facilitating uniform predetermined deformation of hood structure  100 , as discussed in detail below.  
         [0032]     Hood structure  100  may further include mirror-image longitudinal beams  126 ,  128  disposed between crush initiators  122 ,  124 . Beams  126 ,  128  may be provided for maintaining hood structure  100  in a predetermined configuration during a front impact event, as also discussed in detail below. Beams  126 ,  128  may be formed of a similar cross-section and in a similar manner as beams  118 ,  120 .  
         [0033]     Still referring to FIGS.  2 ( b ) and  4 , in order to provide for lateral structural rigidity, as well as for preventing windshield intrusion during a front impact event, a lateral hood beam  130  may be provided generally centrally between crush initiators  122 ,  124 . As shown in  FIG. 5 , beam  130  may include a tapered cross-section for further strengthening the structure of beam  130 , as well as for reducing the overall weight of hood structure  100 .  
         [0034]     Referring next to  FIG. 7 , in the event of a front impact event, hood structure  100  may deform as shown in  FIG. 7  such that crush initiators  122 ,  124  and beams  126 ,  128  (as well as beams  118 ,  120  and  130 ) act in concert to produce a generally inverted U-shaped hood deformation. As shown in  FIG. 7 , upon hood deformation, crush initiators  122 ,  124  may allow for deformation of the hood at edges  132 ,  134 , with longitudinal beams  126 ,  128  providing the reinforcement between the crush initiators for maintaining the hood in the inverted U-shaped configuration illustrated. Yet further, as shown in  FIG. 7 , lateral beams  118 ,  120  may likewise maintain the front and rear edges  102 ,  104 , respectively, in a generally width-wise expanded configuration without allowing the hood from significantly collapsing in the lateral direction. Additionally, as shown in  FIG. 7 , lateral hood beam  130  may also maintain the hood structure in a width-wise expanded configuration while preventing intrusion of the hood structure into the windshield area, as may be the case for hood structures including longitudinal beams in the location of beam  130 .  
         [0035]     Based on the discussion above, hood structure  100  thus provides for predetermined deformation of the hood, generally regardless of the type of contours placed on the outer hood panel. Yet further, hood structure  100  provides for predetermined deformation, without intrusion thereof into the windshield area, while meeting or exceeding existing frontal impact hood deformation characteristics.  
         [0036]     Referring next to FIGS.  2 ( b ),  4  and  5 , in another embodiment of the present invention, hood structure  100  may optionally include a plurality of asymmetrically disposed transverse beams  150  for providing additional rigidity to the structure of the hood. Beams  150  may be formed in a similar cross-sectional configuration as lateral hood beam  130 . Based on the layout illustrated in FIGS.  2 ( b ) and  4 , beams  150  may thus provide for lateral as well as longitudinal rigidity to the structure of the hood. Yet further, based on the tapered cross-sections of beam  150  (as well as beam  130 ), the structure of the hood may deform in a predetermined manner as shown in  FIG. 7 . Moreover, gaps  152  between the various lateral and longitudinal beams may be provided for reducing the overall weight of the hood structure. As shown in  FIG. 2 ( b ), beams  150  may also create an asymmetrical loading condition that allows the deeper sections  131  to be used for providing rigidity (i.e. torsional, deflection etc.) to the hood structure, with the beams then tapering to a reduced depth at area  133  that terminates toward crush initiators  122 ,  124 .  
         [0037]     Referring also to FIGS.  2 ( b ),  4  and  5 , in a yet further embodiment of the present invention, the structure of the hood may be optionally provided with hood mastic adhesive  154  along the tapered edges of beams  130 ,  150  for providing additional rigidity to the structure of the beams. The use of hood mastic adhesive  154  thus allows for stiffening of the hood without increasing the weight thereof with the use of structural rigidifying members, and while also allowing for the use of tapered beam members.  
         [0038]     Although particular embodiments of the invention have been described in detail herein with reference to the accompanying drawings, it is to be understood that the invention is not limited to those particular embodiments, and that various changes and modifications may be effected therein by one skilled in the art without departing from the scope or spirit of the invention as defined in the appended claims.