Patent Document

BACKGROUND OF THE INVENTION 
     1. Technical Field 
     The present invention generally relates to frame assemblies for automotive vehicles and, more particularly, to a structural tube for the front end assembly of a motor vehicle unibody. 
     2. Discussion 
     A front end assembly of a motor vehicle includes various components for supporting the vehicle&#39;s engine, front body panels, and front suspension. In a unibody construction, such a front end assembly commonly includes a pair of rails extending along the longitudinal axis of the vehicle, a bumper beam extending between the pair of rails, a pair of wheel wells disposed outboard of the rails and rearward of the bumper, a fascia coupled between the rearward ends of the wheel wells opposite the bumper beam, and a pair of cowls extending between the bumper beam and fascia outboard of the wheel wells. In order to provide a base for mounting the coolant pack of the vehicle (e.g., the radiator) a support member is sometimes provided behind the bumper beam and between the cowls. 
     According to the prior art, such a support member is bolted to the rails and cowls. While bolting the support member to the other components of the front assembly is satisfactory for providing a platform for mounting the coolant pack, such bolting is susceptible to torsional failure. That is, since bolting provides a point contact between the support member and the rails and/or cowls, the support member does not add substantially to the cross-car stiffness of the front assembly. Under extreme conditions, cross-car torsion may cause the point contacts to break. 
     Bolting also requires numerous parts and manual labor during assembly which adds to manufacturing costs. Additionally, bolting is not conducive to high speed automated processing. Further, bolting does not enable small positional adjustments among the components to account for local build variations. 
     In view of the foregoing, it would be desirable to provide a support member which yields additional cross-car rigidity and stiffness. It would also be desirable to employ an improved connection between the support member and the other components of the front assembly. Additionally, it would be desirable to provide a support member capable of high speed, automated processing. 
     SUMMARY OF THE INVENTION 
     The above and other objects are provided by a front end assembly for a motor vehicle including a U-shaped cross-car support member capable of being spot welded to a pair of cowl members and a pair of rail members. The U-shaped cross-car support member preferably comprises a hydroformed tube having a lower section disposed laterally with respect to a longitudinal axis of the vehicle, a pair of upwardly projecting side sections extending essentially orthogonal to the lower section, and a pair of outwardly projecting end sections extending essentially orthogonal to the upright sections so as to be nearly parallel to the lower section. A cowl bracket is connected to each of the end sections and is spot welded to each of the cowl members. Similarly, a rail bracket is connected to each of the side sections and is spot welded to each of the rails. Advantageously, the ability to spot weld the cowl and rail brackets enables the U-shaped support member to be installed within the front end assembly in a high speed automated process. Further, the welds between the support member and the cowls and rails substantially strengthens the cross-car stiffness of the front end assembly. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     In order to appreciate the manner in which the advantages and objects of the invention are obtained, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings only depict preferred embodiments of the present invention and are not therefore to be considered limiting in scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings in which: 
     FIG. 1 is a perspective view of a front end assembly incorporating the support member of the present invention; 
     FIG. 2 is a perspective view of the U-shaped cross-car support member of the front end assembly of FIG. 1; 
     FIG. 3 is a perspective view of a cowl bracket of the support member of FIG. 2; 
     FIG. 4 is a perspective view of a rail bracket of the support member of FIG. 2; 
     FIG. 5 is a perspective view of a first radiator bracket of the support member of FIG. 2; and 
     FIG. 6 is a perspective view of a second radiator bracket of the support member of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The present invention provides a support member for adding cross-car stiffness to the front end assembly of a motor vehicle. Advantageously, the support member may be spot welded to the other components of the front end assembly thereby enabling high speed automated manufacturing. In addition to the foregoing, the support member provides a convenient platform for mounting the vehicle&#39;s coolant package including the radiator and may be adjusted to account for build variations. 
     Turning now to the drawing figures, FIG. 1 illustrates a front end assembly for a motor vehicle generally at  10 . The front end assembly  10  includes a U-shaped cross-car support member  12  having a pair of rail brackets  14 , a pair of cowl brackets  16  and a pair of radiator brackets  18  connected thereto. A pair of longitudinally extending rails  20  are connected at a forward end to the support member  12 . Preferably, the rails  20  are connected to the support member  12  by spot welding each rail  20  to a complimentary rail bracket  14 . 
     A bumper beam  22  is connected to a distal end of each of the rails  20  so as to extend laterally therebetween. Although any conventional method may be used to couple the bumper beam  22  to the rails  20 , it is presently preferred to use spot welding. A pair of wheel wells  24  are connected to the outboard edges of rails  20  rearward of the bumper beam  22 . The wheel wells  24  are preferably coupled to the rails  20  and bumper beam  22  by bolting although other methods may be substituted therefore. 
     A fascia  26  is connected to the rear end of each of the wheel wells  24  opposite the bumper beam  22  preferably by spot welding. A pair of cowls  28  are connected to the outboard edge of the wheel wells  24  rearward of the bumper beam  22 . The cowls  28  are also connected to the support member  12  and fascia  26 . Preferably, the cowls  28  are connected to the support member  12  by spot welding each cowl  28  to a cowl bracket  16 . A cross beam  30  is connected to each arm of the support member  12  so as to extend thereacross. Preferably, the cross beam  30  is connected to the support member  12  with fasteners such as bolts. 
     Turning now to FIG. 2, the U-shaped cross-car support member  12  is shown in greater detail. The support member  12  includes a first or lateral section  32 , a pair of second or upright sections  34  integrally formed with the lateral section  32  at either end thereof, and a pair of third or end sections  36  integrally formed with the upright sections  34  at an opposite end as the lateral section  32 . As can be seen, the upright sections  34  extend essentially orthogonal to the lateral section  32  while the end sections  36  project outwardly from the upright sections  34  so as to be essentially parallel with the lateral section  32 . Although the term “upright” is used herein to describe the second sections  34 , it should be noted that this does not necessarily mean that the second sections  34  are vertical but, rather, are upwardly projecting relative to the lateral section  32  even if at an angle. 
     The support member  12  is preferably tubular and incudes a leading edge  38 , a trailing edge  40 , an inboard surface  42  and outboard surface  44 . The inboard and outboard surfaces  42  and  44  extend between the leading edge  38  and trailing edge  40  to provide the support member  12  with a generally triangularly shaped cross-section. Although other methods may be used in forming the support member  12  to its desired configuration, it is presently preferred to use the hydroform technique. During or after formation of the support member  12 , contact points such as apertures  46  in the end sections  36  may be formed for accommodating additional components such as the cross beam  30  (see FIG.  1 ). If desired, additional plates, such as end plates  48 , can be mounted to the support member  12  for added rigidity. 
     As noted in FIG. 1, a pair of cowl brackets  16  are connected to the support member  12 . More particularly, the cowl brackets  16  are connected to the distal end of the end sections  36 . Although other techniques are available for connecting the cowl brackets  16  to the end sections  36 , it is presently preferred to use a bead of weld and in particular, a MIG weld. In contrast to bolting, welding enables the cowl bracket  16  to be adjusted slightly inboard or outboard to control the width of the vehicle. Although such an adjustment may be small, e.g., 2 mm, it accounts for build variations. 
     Referring momentarily to FIG. 3, the cowl bracket  16  is illustrated in greater detail. The cowl bracket  16  includes a triangular shaped body portion  50  having an annular flange  52  radially projecting substantially about an outer perimeter thereof. The annular flange  52  is specifically designed so as to enable spot welding of the cowl bracket  16  to the cowls  28  (see FIG.  1 ). The cowl bracket  16  also includes a plurality of axially extending flanges  54  projecting from an inner perimeter thereof perpendicularly relative to the annular flange  52 . In the preferred embodiment, three axial flanges  54  are provided. 
     The inner perimeter of the body portion  50  and the axial flanges  54  define a central aperture  56  of the cowl bracket  16 . Aperture  56  is shaped so as to compliment the circumferential surface of the end sections  36  of the support member  12  (see FIG.  2 ). As such, the cowl bracket  16  may be slidably disposed over the end sections  36  so that the axial flanges  54  are adjacent thereto. Thereafter, the axial flanges  54  may be welded to the inboard surface  42 , outboard surface  44  and trailing edge  40  of the end sections  36 . 
     Referring again to FIG. 2, the pair of rail brackets  14  are connected in an overlapping fashion to the outboard surface  44  of the upright sections  34 . Although other methods may be employed, it is presently preferred to connect the rail brackets  14  to the upright sections  34  with a bead of weld and particularly a MIG weld. As opposed to bolting, welding enables the inboard/outboard position of the rail brackets  14  to be controlled. This enables adjustment to the width to account for build variations. 
     Referring momentarily to FIG. 4, a rail bracket  14  is illustrated in greater detail. The rail bracket  14  includes an outboard surface  58  integrally formed with a pair of side surfaces  50 . The side surfaces  50  project essentially orthogonally with respect to the outboard surface  58 . A pair of outwardly projecting flanges  62  are integrally formed with the side surfaces  50 . The flanges  62  preferably project in a plane which is essentially parallel to the outboard surface  58  and essentially perpendicular to the side surfaces  60 . 
     The flanges  62  are specifically formed to be spot weldable to the rails  20  (see FIG.  1 ). If desired, the flanges  62  may be shaped so as to compliment the receiving surface of the rails  20 . Each of the side surfaces  60  as well as the outboard surface  58  includes at least one aperture  64  formed therein. Each aperture  64  facilitates welding of the rail bracket  14  to the leading edge  38 , trailing edge  40  and outboard surface  44  of the upright sections  34  of the support member  12  (see FIG.  2 ). 
     Turning again to FIG. 2, the radiator brackets  18  include a passenger side radiator bracket  18   a  and a driver side radiator bracket  18   b  which are connected to the inboard surface  42  of the upright sections  34  of the support member  12 . Although other techniques may be used, it is presently preferred to connect the radiator brackets  18   a, b  to the upright sections  34  with a bead of weld, particularly a MIG weld. Referring momentarily to FIG. 5, the passenger side radiator bracket  18   a  is illustrated in greater detail. 
     The radiator bracket  18   a  includes a top section  66 , having a front flange  68 , rear flange  70  and side flange  72  integrally formed therewith. The front flange  68  extends essentially perpendicular to the top section  66  and includes a radiator mounting portion  74  transitioning to a support member mounting portion  76 . The transition from the support member mounting portion  76  to the radiator mounting portion  74  is preferably stepped away from the plane of the support member mounting portion  76 . In this way, clearance is provided between a radiator eventually mounted to the radiator mounting portion  74  and the support member  12 . To accommodate the mounting of a radiator to the radiator bracket  18   a , the radiator mounting porion  54  is preferably provided with a recessed section  78  having an aperture  80  formed therethrough. 
     The rear flange  70  projects downwardly with respect to the top section  66  and is preferably formed essentially perpendicular thereto. The rear flange  70  and front flange  68  are essentially parallel and preferably project beyond an outboard edge  82  of the top section  66 . In this way, the front flange  68  and rear flange  70  may be positioned so as to overlap the leading edge  38  and trailing edge  40  of the upright section  34  of the support member  12  (see FIG.  2 ). Thereafter, the flanges  68  and  70  may be welded thereto. 
     The side flange  72  is upturned relative to the top section  66  and preferably projects essentially perpendicularly thereto. When the radiator bracket  18   a  is placed on the upright section  34  of the support member  12 , the side flange  72  is adjacent to the inboard surface  42  (see FIG.  2 ). Thereafter, the flange  72  may be welded thereto. Preferably, a pair of apertures  84  are provided in the top section  66  for accommodating additional mounting structure of a radiator eventually mounted thereto. 
     Referring now to FIG. 6, a more detailed view of the driver side radiator bracket  18   b  of FIG. 2 is illustrated. The driver side radiator bracket  18   b  includes a bottom section  86  having a front flange  88  and a rear flange  90  extending therefrom. The front flange  88  is preferably integrally formed with the bottom section  86  and is upturned relative thereto so as to extend essentially perpendicularly relative to the bottom section  86 . The front flange  88  includes a radiator mounting porion  92  transitioning to a support member mounting portion  94 . The transition from the support mounting portion  94  to the radiator mounting portion  92  is preferably stepped out with respect to the plane of the support member mounting portion  94 . In this way, clearance is provided between a radiator eventually mounted to the radiator mounting portion  92  and the support member  12 . To accommodate the mounting of a radiator thereto, the radiator mounting portion  92  preferably includes a recessed section  96  having an aperture  98  formed therein. 
     The rear flange  90  is preferably formed integrally with the bottom section  86  and upwardly projects perpendicularly thereto. The rear flange  90  and front flange  88  are preferably parallel and project beyond the outboard edge  100  of the bottom section  86 . In this way, the rear flange  90  and front flange  88  may be positioned so as to overlap the trailing edge  40  and leading edge  38  of the upright section  34  of the support member  12  (see FIG.  2 ). Thereafter, the flanges  88  and  90  may be welded thereto. If desired, a down-turned side flange (not shown) may be provided on the outboard edge  100  of the bottom section  86  to provide a surface for mounting to the inboard surface  42  of the support member  12 . Also, the bottom section  86  may be provided with at least one aperture  102  for accommodating additional mounting structure of a radiator eventually secured thereto. 
     Referring again to FIG. 1, in a manufacturing process, the front end assembly  10  is preferably assembled by providing the support member  12  having the rail brackets  14 , cowl brackets  16  and radiator brackets  18  connected thereto. Thereafter, the rails  20  are connected to the rail brackets  14  preferably by spot welding. The bumper beam  22  is then mounted to the rails  20 . The wheel wells  24  and cowls  28  are then mounted to the bumper beam  22 , rails  20 , and support member  12 . The cowls  28  are preferably connected to the support member  12  by spot welding the cowls  28  to the cowl brackets  16 . Thereafter, the cross beam  30  is bolted to the support member  12  and the fascia  26  is connected to the cowls  28 . Subsequently, a radiator (not shown) is mounted to the radiator brackets  18 . 
     Thus, a support member is provided for the front end assembly of a motor vehicle which includes brackets to enable spot welding by a high speed automated process. Due to the welding of the support member to the cowls and rails, the support member adds substantial cross-car stiffness to the front end assembly. Due to the welding of the brackets to the support member, the width of the support member can be controlled to account for build variations. Advantages in terms of piece part cost procurement, labor reduction, and weight removal are also realized. 
     Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the present invention can be implemented in a variety of forms. Therefore, while this invention has been described in connection with particular examples thereof, the true scope of the invention should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, specification, and following claims.

Technology Category: b