Patent Publication Number: US-10766529-B2

Title: Cowl cross bar for vehicle

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application is a Divisional of U.S. patent application Ser. No. 15/341,252, filed Nov. 2, 2016, which claims priority to Korean Patent Application No. 10-2016-0067929, filed Jun. 1, 2016, the entire contents of which applications are incorporated herein for all purposes by these references. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The present disclosure relates to a cowl cross bar for a vehicle. More particularly, it relates to a cowl cross bar for a vehicle which is configured such that the coupling structure between a main cross bar in front of a driver&#39;s seat and a sub-cross bar in front of a passenger seat is improved, whereby the stiffness of the cowl cross bar can be enhanced. 
     Description of Related Art 
     Generally, a cowl cross bar is provided in the front of a vehicle to support a steering apparatus such that the steering apparatus is fixed to a vehicle body. The cowl cross bar is directly mounted to the vehicle body in such a manner that cowl cross bar is disposed perpendicular to a steering column of the steering apparatus and oriented to extend in a transverse direction of the vehicle. 
     The cowl cross bar has a structure capable of absorbing vibration transmitted from the steering apparatus and resisting the vibration. In addition, the cowl cross bar is configured to increase the stiffness so as to enhance characteristics of resisting vibration transmitted from a steering wheel. 
     A conventional cowl cross bar is configured such that a main cross bar disposed in front of the driver&#39;s seat is coupled, by a center support bracket, with a sub-cross bar disposed in front of the passenger seat. The main cross bar and the sub-cross bar may be eccentrically disposed depending on a design by taking into account the layout of internal components of the vehicle. 
     However, the conventional cowl cross bar is problematic in that the stiffness thereof is reduced because of the eccentricity between the main cross bar and the sub-cross bar, whereby crashworthiness and vibration characteristics deteriorate. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art. 
     BRIEF SUMMARY 
     Various aspects of the present invention are directed to providing a cowl cross bar for a vehicle which is configured such that the optimal coupling structure between a main cross bar in front of a driver&#39;s seat and a sub-cross bar in front of a passenger seat is embodied depending on an eccentric rate between the main cross bar and the sub-cross bar, whereby the stiffness of the cowl cross bar can be effectively enhanced. 
     According to various aspects of the present invention, a cowl cross bar for a vehicle may include a main cross bar disposed in front of a driver&#39;s seat in a transverse direction of the vehicle, a sub-cross bar disposed in front of a passenger seat in the transverse direction of the vehicle, and a center supporter configured to couple the main cross bar and the sub-cross bar to each other such that diametric centers thereof are disposed eccentrically relative to each other, and the center supporter may include a main center support bracket provided with a connector to which a longitudinal end of the sub-cross bar is fixed, and a sub-center support bracket fixed to the main center support bracket, and having an insert hole through which a longitudinal end of the main cross bar is fixed to the sub-center support bracket. 
     The main cross bar and the sub-cross bar may be disposed such that a sum of a radius of the main cross bar and a radius of the sub-cross bar is less than a distance between the diametric center of the main cross bar and the diametric center of the sub-cross bar. 
     The connector may protrude in a conical shape from the main center support bracket, the longitudinal end of the sub-cross bar may have an expanded pipe shape, and the connector may be inserted into and fixed to the longitudinal end of the sub-cross bar. 
     A bonding flange may be provided around the insert hole, and the longitudinal end of the main cross bar that is inserted into the insert hole may be enclosed by and fixed to the bonding flange. 
     An edge of the main center support bracket may be fixed to a sub flange of the sub-center support bracket, and the connector and the insert hole are disposed to be stepped from each other. 
     According to various aspects of the present invention, a cowl cross bar for a vehicle may include a main cross bar disposed in front of a driver&#39;s seat in a transverse direction of the vehicle, a sub-cross bar disposed in front of a passenger seat in the transverse direction of the vehicle, and a center support bracket configured to couple the main cross bar and the sub-cross bar to each other such that diametric centers thereof are disposed eccentrically relative to each other, in which the center support bracket may have a cross-sectional structure enclosing a longitudinal end of the main cross bar, and may include a main bonding part and a main lower flange that are fixed to an outer circumferential surface of the main cross bar, and a sub-side flange fixed to an outer circumferential surface of the sub-cross bar. 
     The main cross bar and the sub-cross bar may be disposed such that a distance between the diametric center of the main cross bar and the diametric center of the sub-cross bar is a value obtained by subtracting a radius of the sub-cross bar from a radius of the main cross bar. 
     A longitudinal end of the sub-cross bar may be inserted into the main cross bar and disposed such that an outer circumferential surface of the sub-cross bar comes into contact with an inner circumferential surface of the main cross bar. 
     The center support bracket may include, to enclose a lower portion of the longitudinal end of the main cross bar in a “C”-shape, a center part and a side part bent from opposite sides of the center part, wherein the main lower flange and the sub-side flange are formed on an upper end of the center part, and the main bonding part may be formed on an upper end of the side part. 
     A welding hole may be formed in a portion of the longitudinal end of the main cross bar in which the sub-cross bar is inscribed, and the main cross bar and the sub-cross bar may be bonded to each other in the welding hole. 
     According to various aspects of the present invention, a cowl cross bar for a vehicle may include a main cross bar disposed in front of a driver&#39;s seat in a transverse direction of the vehicle, a sub-cross bar disposed in front of a passenger seat in the transverse direction of the vehicle, and a center supporter configured to couple the main cross bar and the sub-cross bar to each other such that diametric centers thereof are disposed eccentrically relative to each other, and the center supporter may include a main center support bracket fixed to an outer circumferential surface of a longitudinal end of the main cross bar, and provided with a connector to which a longitudinal end of the sub-cross bar is fixed, and a sub-center support bracket including an upper end fixed to the outer circumferential surface of the longitudinal end of the main cross bar, and a lower end fixed to the main center support bracket. 
     The main cross bar and the sub-cross bar may be disposed such that a sum of a radius of the main cross bar and a radius of the sub-cross bar may be less than a distance between the diametric center of the main cross bar and the diametric center of the sub-cross bar. 
     The main center support bracket may include, to have a “C”-shaped cross-sectional structure, a center part and a side part bent from opposite sides of the center part, in which a main lower flange may be provided on an upper end of the center part and fixed to the outer circumferential surface of the longitudinal end of the main cross bar, and a main bonding part may be provided on an upper end of the side part and fixed to the outer circumferential surface of the longitudinal end of the main cross bar. 
     The sub-center support bracket may be disposed at a position spaced apart from the center part by a predetermined distance in a longitudinal direction of the main cross bar, and the main cross bar, the main center support bracket and the sub-center support bracket may be coupled to each other in a closed cross-sectional structure. 
     An insert hole may be formed in the sub-center support bracket so that the longitudinal end of the sub-cross bar is fixed to the sub-center support bracket through the insert hole, and the longitudinal end of the sub-cross bar passes through the connector and is fixed thereto, and is inserted into the insert hole and fixed to the sub-center support bracket. 
     A bonding flange may be provided around the insert hole, and the longitudinal end of the sub-cross bar that is inserted into the insert hole may be enclosed by and fixed to the bonding flange. 
     The connector may protrudes in a conical shape from the sub-center support bracket, the longitudinal end of the sub-cross bar may have an expanded pipe shape, and the connector may be fixed to the longitudinal end of the sub-cross bar in a circumscribed state. 
     It is understood that the term “vehicle” or “vehicular” or other similar terms as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuel derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example, both gasoline-powered and electric-powered vehicles. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic view illustrating a layout structure of a cowl cross bar provided with a center supporter according to various embodiments of the present invention. 
         FIG. 2  is a partial perspective view illustrating the center supporter of the cowl cross bar according to various embodiments of the present invention. 
         FIG. 3  is a sectional view illustrating the center supporter of the cowl cross bar according to various embodiments of the present invention. 
         FIG. 4  is a schematic view illustrating a layout structure of a cowl cross bar provided with a center support bracket (center supporter) according to various embodiments of the present invention. 
         FIG. 5A  and  FIG. 5B  are views illustrating a detailed structure and a coupling structure of the center support bracket of the cowl cross bar according to various embodiments of the present invention. 
         FIG. 6  is a sectional view taken along line A-A of  FIG. 5B . 
         FIG. 7  is a sectional view taken along line B-B of  FIG. 5B . 
         FIG. 8  is a bottom view seen from the direction designated by the arrow C of  FIG. 5B . 
         FIG. 9  is a schematic view illustrating a layout structure of a cowl cross bar provided with a center supporter according to various embodiments of the present invention. 
         FIG. 10  is a perspective view illustrating the center supporter of the cowl cross bar according to various embodiments of the present invention. 
         FIG. 11  is a sectional view illustrating the center supporter of the cowl cross bar according to various embodiments of the present invention. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
     DETAILED DESCRIPTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     Various embodiments of the present invention relate to a cowl cross bar in which a main cross bar disposed at one of left and right sides in a transverse direction of a vehicle and a sub-cross bar disposed at the other side are coupled to each other by a center supporter. In various embodiments of the present invention, the optimized stiffness depending on an eccentric rate between the main cross bar and the sub-cross bar can be secured by an improved coupling structure of the center supporter. 
     In the case of the cowl cross bar for a vehicle, eccentricity may be caused between the main cross bar and the sub-cross bar depending on a design taking into account the layout or the like of internal components (for example, an air vent, an AVN, etc.) of the vehicle. An eccentric rate may be changed to various values depending on the design. 
     Given this, the present invention proposes three types of coupling structures according to eccentric rates (diametric center eccentric rates) between the main cross bar that is disposed in front of a driver&#39;s seat in the transverse direction of the vehicle and the sub-cross bar that is disposed in front of a passenger seat in the transverse direction of the vehicle, whereby the optimized stiffness of the cowl cross bar can be effectively secured for each layout structure of the cowl cross bar. 
     Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
     First Embodiment 
     In  FIG. 1 , there is illustrated a schematic layout structure of a cowl cross bar provided with a center supporter according to a first embodiment. In  FIGS. 2 and 3 , there is illustrated a detailed structure of the center supporter according to the first embodiment. 
     As shown in  FIG. 1 , in the cowl cross bar  10 , a main cross bar  11  and a sub-cross bar  12  may be disposed such that the sum of the radius of the main cross bar  11  and the radius of the sub-cross bar  12  is less than the distance between a diametric center (that is, a circle center) of the main cross bar  11  and a diametric center of the sub-cross bar  12 . 
     As such, the cowl cross bar  10  having the layout structure of the main cross bar  11  and the sub-cross bar  12  that are disposed such that the diametric centers thereof are positioned eccentrically relative to each other includes a center supporter  13 , which has a structure shown in  FIGS. 2 and 3  and is provided between the main cross bar  11  and the sub cross bar  12  so as to secure effective stiffness enhancement according to an eccentric rate. 
     Referring to  FIGS. 2 and 3 , the center supporter  13  includes a main center support bracket  14  to which one longitudinal end of the sub-cross bar  12  is fixed, and a sub-center support bracket  17  to which one longitudinal end of the main cross bar  11  is fixed. 
     The main center support bracket  14  is disposed to extend in a direction approximately perpendicular to the longitudinal direction of the main cross bar  11  and the sub-cross bar  12 . A connector  15  is provided on an upper longitudinal end of the main center support bracket  14  so that the longitudinal end of the sub-cross bar  12  is fixed to and supported by the connector  15 . 
     The connector  15  protrudes toward the sub-cross bar  12  from the upper end of the main center support bracket  14  that is disposed between the main cross bar  11  and the sub-cross bar  12 . In this regard, the connector  15  protrudes in a conical shape in which the diameter thereof is gradually reduced in the transverse direction (or the protruding direction). 
     The longitudinal end of the sub-cross bar  12  that is fixed to the connector  15  has an expanded pipe shape in which the diameter thereof is gradually increased toward a distal end in the longitudinal direction. 
     The expanded-pipe-shaped longitudinal end of the sub-cross bar  12  is bonded to an outer circumferential surface of the conical connector  15  by welding. In other words, since the conical connector  15  is inserted into and bonded to the expanded-pipe-shaped longitudinal end of the sub-cross bar  12 , the section modulus of the junction therebetween is increased, whereby the bending stiffness of the junction part of the sub-cross bar  12  coupled to the main cross bar  11  can be enhanced. 
     For example, an inclined angle of the junction surface between the conical connector  15  and the expanded-pipe-shaped longitudinal end of the sub-cross bar  12  may range from 30° to 60°. 
     Furthermore, the sub-center support bracket  17  is bonded to the upper end of the main center support bracket  14  by welding. An insert hole  18  is formed in the sub-center support bracket  17  so that the longitudinal end of the main cross bar  11  is supported by and fixed to the sub-center support bracket  17  through the insert hole  18 . 
     In more detail, an edge of the main center support bracket  14  that has a cross-section structure bent to have a U-shape is bonded by welding to a sub-flange  19  formed on a peripheral part of the sub-center support bracket  17 . The insert hole  18  is formed in an upper end of the sub-center support bracket  17  and, in detail, disposed over the connector  15  of the main center support bracket  14 . That is, the insert hole  18  and the connector  15  are disposed to be stepped from each other. 
     A bonding flange  18   a  protruding toward the main cross bar  11  is provided around the insert hole  18 . An outer circumferential surface of the longitudinal end of the main cross bar  11  that is inserted into the insert hole  18  is enclosed by and welded to the bonding flange  18   a.    
     In the cowl cross bar  10  having the above structure in which the main cross bar  11  and the sub-cross bar  12  are coupled to each other, the bending stiffness which may be reduced due to the eccentricity between the main cross bar  11  and the sub-cross bar  12  can be reinforced. Therefore, the stiffness against a collision, vibration or the like can be enhanced, and the degree of freedom in designing the internal components for an interior design of the vehicle can be improved. 
     Second Embodiment 
     In  FIG. 4 , there is illustrated a schematic layout structure of a cowl cross bar provided with a center support bracket (center supporter) according to a second embodiment. In  FIGS. 5A to 8 , there are illustrated a detailed structure of the center support bracket and a coupling structure between a main cross bar and a sub-cross bar, according to the second embodiment. 
     Typically, the main cross bar has a diameter greater than that of the sub-cross bar. Therefore, as shown in  FIG. 4 , in the cowl cross bar  20 , the main cross bar  21  and the sub-cross bar  22  may be disposed such that the distance between a diametric center of the main cross bar  21  and a diametric center of the sub-cross bar  22  is a value obtained by subtracting the radius of the sub-cross bar  22  from the radius of the main cross bar  21 . For reference, the length of the sub-cross bar  22  is greater than that of the main cross bar  21 . 
     As such, the cowl cross bar  20  having the layout structure of the main cross bar  21  and the sub-cross bar  22  that are disposed such that the diametric centers thereof are positioned eccentrically relative to each other may be configured such that the sub-cross bar  22  is inserted into and partially overlapped with the main cross bar  21  so as to enhance the stiffness of the junction between the main cross bar  21  and the sub-cross bar  22 . In this case, to appropriately enhance the stiffness depending on an eccentric rate between the main cross bar  21  and the sub-cross bar  22 , a center support bracket  24  having the configuration shown in  FIGS. 5A to 8  is provided as the center supporter between the main cross bar  21  and the sub-cross bar  22 . 
     Referring to  FIGS. 5A to 8 , one longitudinal end of the sub-cross bar  22  is inserted into and inscribed in one longitudinal end of the main cross bar  21 . That is, an outer circumferential surface of the longitudinal end of the sub-cross bar  22  makes partial contact with an inner circumferential surface of the longitudinal end of the main cross bar  21 . 
     The center support bracket  24  functions to couple the main cross bar  21  and the sub-cross bar  22  that are disposed such that the diametric centers thereof are positioned eccentrically relative to each other. The center support bracket  24  has a C ⊏-shaped cross-section, which encloses the longitudinal end of the main cross bar  21 . Further, the center support bracket  24  is disposed to extend in a direction approximately perpendicular to the longitudinal direction of the main cross bar  21  and the sub-cross bar  22 . Main bonding parts  25 , a main lower flange  26  and sub-side flanges  27  are formed on an upper longitudinal end of the center support bracket  24  so as to support and fix the longitudinal ends of the main cross bar  21  and the sub-cross bar  22 . 
     In detail, the center support bracket  24  includes, to enclose a lower portion of the longitudinal end of the main cross bar  21  in a U shape, a center part  24   a  and side parts  24   b  which are bent from opposite edges of the center part  24   a . An upper end of the center part  24   a  comes into contact with the longitudinal end of the main cross bar  21 . Upper ends of the side parts  24   b  come into contact with the outer circumferential surface of the main cross bar  21  and are bonded thereto by welding. 
     The main lower flange  26  which is fixed to the outer circumferential surface of the longitudinal end of the main cross bar  21 , and the sub-side flanges  27  which are fixed to the outer circumferential surface of the longitudinal end of the sub-cross bar  22 , are formed in the upper end of the center part  24   a . The main bonding parts  25  which are fixed to the outer circumferential surface of the longitudinal end of the main cross bar  21  are provided in the upper ends of the respective opposite side parts  24   b . In this regard, the main bonding parts  25  are provided as the upper distal ends of the respective side parts  24   b.    
     In more detail, after the main bonding parts  25  and the main lower flange  26  have been bonded to the outer circumferential surface of the main cross bar  21 , the sub-side flanges  27  are bonded to the outer circumferential surface of the sub-cross bar  22  by welding. 
     In this regard, on the basis of the front, rear, up and down directions of the vehicle, the main bonding parts  25  are fixed to approximately opposite front and rear portions of the outer circumferential surface of the main cross bar  21 . The main lower flange  26  is fixed to a lower portion of the outer circumferential surface of the main cross bar  21 . The sub-side flanges  27  are fixed to approximately opposite front and rear portions of the outer circumferential surface of the sub-cross bar  22 . 
     Furthermore, referring to  FIG. 8 , a welding hole  28  to be used for welding of the sub-cross bar  22  is formed in a lower portion of the main cross bar  21  in which the sub-cross bar  22  is inscribed. The main cross bar  21  and the sub-cross bar  22  can be more reliably bonded to each other through the welding hole  28 . 
     Due to the above-mentioned coupling structure between the main cross bar  21  and the sub-cross bar  22 , the stiffness of the cowl cross bar  20  which may be reduced because of the eccentricity between the main cross bar  21  and the sub-cross bar  22  can be effectively reinforced. Therefore, the stiffness of the cowl cross bar  20  against a collision, vibration or the like can be secured, and the degree of freedom in designing the internal components for an interior design of the vehicle can be enhanced. 
     Third Embodiment 
     In  FIG. 9 , there is illustrated a schematic layout structure of a cowl cross bar provided with a center supporter according to a third embodiment. In  FIGS. 10 and 11 , there are illustrated a detailed structure of the center supporter and a coupling structure between the main cross bar and a sub-cross bar, according to the third embodiment. 
     As shown in  FIG. 9 , in the cowl cross bar  30 , a main cross bar  31  and a sub-cross bar  32  may be disposed such that the sum of the radius of the main cross bar  31  and the radius of the sub-cross bar  32  is less than the distance between a diametric center of the main cross bar  31  and a diametric center of the sub-cross bar  32 . 
     As such, in the case of the cowl cross bar  30  having the layout structure of the main cross bar  31  and the sub-cross bar  32  that are disposed such that the diametric centers thereof are positioned eccentrically from each other, a center supporter  33  which has a structure shown in  FIGS. 10 and 11  is provided between the main cross bar  31  and the sub cross bar  32  so as to provide optimal stiffness enhancement according to an eccentric rate. 
     Referring to  FIGS. 10 and 11 , the center supporter  33  includes a main center support bracket  34  and a sub-center support bracket  38 . 
     The main center support bracket  34  is disposed to extend in a direction approximately perpendicular to the longitudinal direction of the main cross bar  31  and the sub-cross bar  32 . The main center support bracket  34  is fixed to an outer circumferential surface of one longitudinal end of the main cross bar  31  by welding. 
     For this, main bonding parts  35  and a main lower flange  36  which are fixed to the longitudinal end of the main cross bar  31  are provided in an upper longitudinal end of the main center support bracket  34 . In detail, the main center support bracket  34  includes a center part  34   a  and side parts  34   b  which are bent from opposite transverse side edges of the center part  34   a , and thus generally has a ⊏-shaped (C-shaped) cross-sectional structure. The main lower flange  36  is formed in an upper end of the center part  34   a . The main bonding parts  35 , each of which extends longer than the center part  34   a , are provided on upper ends of the respective side parts  34   b.    
     In the main center support bracket  34  having the above-mentioned configuration, on the basis of the front, rear, up and down directions of the vehicle, the main bonding part  35  is bonded to approximately opposite front and rear portions of the outer circumferential surface of the main cross bar  31  by welding. The main lower flange  36  is bonded to a lower portion of the outer circumferential surface of the main cross bar  31  by welding. 
     Furthermore, a connector  37  is provided on the center part  34   a  of the main center support bracket  34  so that one longitudinal end of the sub-cross bar  32  is supported on and fixed to the connector  37 . 
     The connector  37  protrudes toward the sub-cross bar  32  from the upper end of the center part  34   a  of the main center support bracket  34  that is disposed between the main cross bar  31  and the sub-cross bar  32 . In this regard, the connector  37  has a conical shape in which the diameter thereof is gradually reduced in the protruding direction (that is, in the longitudinal direction of the sub-cross bar). 
     The longitudinal end of the sub-cross bar  32  fixed to the connector  37  has an expanded pipe shape in which the diameter thereof is gradually increased toward a distal end in the longitudinal direction. 
     The expanded-pipe-shaped longitudinal end of the sub-cross bar  32  is inserted into the conical connector  37  and fixed thereto by welding in a circumscribed state. In other words, an inner circumferential surface of the conical connector  37  is bonded to an outer circumferential surface of the expanded-pipe-shaped longitudinal end of the sub-cross bar  32 . Thus, the section modulus of the junction therebetween is increased, whereby the bending stiffness of the junction part of the sub-cross bar  32  coupled to the main cross bar  31  can be enhanced. 
     Furthermore, the expanded-pipe-shaped longitudinal end of the sub-cross bar  32  passes through the sub-center support bracket  38  and then is fixed to the sub-center support bracket  38  by welding. Thus, the bending stiffness of the junction part of the sub-cross bar  32  can be further enhanced. 
     The sub-center support bracket  38  is fixed between the longitudinal end of the main cross bar  31  and the main center support bracket  34  by welding. A sub-upper flange  39  provided in the upper end of the sub-center support bracket  38  is bonded to a lower portion of the outer circumferential surface of the longitudinal end of the main cross bar  31 . A sub-lower flange  40  provided in a lower end of the sub-center support bracket  38  is bonded to an upper end (in detail, below the junction part) of the main center support bracket  34 . An insert hole  41  is formed in the sub-center support bracket  38  between the sub-upper flange  39  and the sub-lower flange  40  so that the expanded-pipe-shaped longitudinal end of the sub-cross bar  32  is supported by the sub-center support bracket  38  through the insert hole  41 . 
     A bonding flange  41   a  protruding toward the main cross bar  31  is provided around the insert hole  41 . The expanded-pipe-shaped longitudinal end of the sub-cross bar  32 , which passes through the insert hole  41  and is supported by the sub-center support bracket  38 , is enclosed by the bonding flange  41   a  and bonded thereto by welding. 
     As such, the expanded-pipe-shaped longitudinal end of the sub-cross bar  32  not only passes through the connector  37  of the main center support bracket  34  and is bonded thereto but also passes through the insert hole  41  of the sub-center support bracket  38  and is bonded to the sub-center support bracket  38 . Thus, the stiffness of the junction part of the sub-cross bar  32  coupled to the main cross bar  31  can be further enhanced. 
     As shown in  FIG. 11 , in the longitudinal end of the sub-cross bar  32 , only a portion thereof that is welded to the connector of the main center support bracket  34  has an expanded pipe shape, and a portion thereof that is fitted into the insert hole  41  of the sub-center support bracket  38  may have a normal pipe shape (not expanded-pipe shape). 
     Furthermore, as stated above, the sub-center support bracket  38  is welded to and fixed between the main cross bar  31  and the main center support bracket  34  through the sub-upper flange  39  and the sub-lower flange  40 . In this regard, the sub-center support bracket  38  is disposed at a position spaced apart from the center part  34   a  of the main center support bracket  34  in the longitudinal direction of the main cross bar  31 . Therefore, the main cross bar  31 , the main center support bracket  34  and the sub-center support bracket  38  are coupled to one another to have a closed cross-sectional structure, whereby the bending stiffness of the cowl cross bar  30  can be further enhanced. 
     Furthermore, the sub-center support bracket  38  includes support flanges  42  on respective opposite side edges thereof in the transverse direction. The support flanges  42  are seated on and bonded to edges of the respective side parts  34   b  of the main center support bracket  34 . 
     In the main cross bar  31  and the sub-cross bar  32  that are coupled to each other in the above-mentioned structure, the bending stiffness which is reduced due to the eccentricity between the main cross bar  31  and the sub-cross bar  32  can be enhanced. Therefore, the stiffness of the cowl cross bar  30  against a collision, vibration or the like can be secured, and the degree of freedom in designing the internal components for an interior design of the vehicle can be enhanced. 
     Meanwhile, the center supporter  33  may be manufactured by die-casting a magnesium material or pressing a steel material. 
     Furthermore, in the case of the main center support bracket  34 , so as to reduce the weight thereof, a weight reducing hole  43  may be formed in a region in which the significance of the stiffness is relatively low. A separate reinforcing plate  44  may be provided on a region in which the significance of the stiffness is relatively high. For example, the reinforcing plate  44  may be disposed on a lower end of the main center support bracket  34  (refer to  FIG. 10 ). 
     Although not shown in the drawings, the cowl cross bar  30  is configured such that each of the other longitudinal ends of the main cross bar  31  and the sub-cross bar  32  is supported by and coupled to the vehicle body, and the cowl cross bar  30  is also supported by and coupled to the vehicle body by a cowl bracket (not shown) coupled to the outer circumferential surface of the main cross bar  31 . 
     In a cowl cross bar for a vehicle according to various embodiments of the present invention, the optimal coupling structure between a main cross bar and a sub-cross bar is embodied depending on an eccentric rate between the main cross bar and the sub-cross bar, whereby the stiffness of the cowl cross bar can be effectively enhanced. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper” or “lower”, “inner” or “outer” and etc. are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.