Abstract:
The invention concerns an automotive vehicle having a roof pillar defining a structurally-integrated HVAC duct. The structurally-integrated HVAC duct includes an interior surface having an insulating coating covering the surface. The invention also concerns a method of forming a structural HVAC duct that includes coating a surface that forms an interior of the duct with an insulating coating.

Description:
BACKGROUND OF INVENTION  
       [0001]     The present invention relates generally to an HVAC duct in a vehicle, and in particular to an HVAC duct integrated into a roof pillar of an automotive vehicle and a method of forming the duct.  
         [0002]     In many automotive vehicles today, the heating, ventilation and air conditioning (HVAC) system includes vents in or near the headliner. Sport utility, multi-activity, and station wagons, in particular, may include such vents, which may receive air from a rear auxiliary unit. A blower, and other components of the auxiliary system, are typically located in a side wall with ducts extending up along or within one or more of the roof pillars to direct air to these upper vents. For auxiliary HVAC units, the ducts typically extend along or within one or more of the C-pillars and D-pillars. Separate ducts are employed because an insulating layer is needed between the heated or cooled air flowing through the ducts and the metal (typically steel or aluminum) roof pillars, which are not effective for maintaining the temperature of the flowing air.  
         [0003]     If the HVAC duct will be contained between two or more stampings, then a separate insulating HVAC duct is typically inserted between the stampings before the stampings are permanently secured together. If the HVAC duct will be contained within a closed section that does not have any severe bends, then the separate HVAC duct is also typically mounted inside the closed section. Unfortunately, the separate duct has fabrication and assembly costs, which add to the cost of the vehicle. Moreover, in both of these cases, the materials for this duct are relatively expensive since they must maintain their shape while withstanding the high temperatures of a paint oven. If the roof pillar includes a closed section that does have severe bends, then a separate HVAC duct is typically mounted adjacent to but outside of the closed section. Not only are the extra fabrication and assembly costs incurred with this adjacent duct, but the duct now takes up extra space.  
         [0004]     Thus, it is desirable to eliminate the extra cost of fabrication and assembly—and sometimes extra space taken—for these HVAC ducts running through or along roof pillar components.  
       SUMMARY OF INVENTION  
       [0005]     An embodiment of the present invention contemplates an automotive vehicle having a body with a roof and a roof pillar extending to and supporting the roof. The roof pillar includes at least one hollow structural member defining a structural HVAC duct including an interior surface for airflow there through, and having an insulating coating covering substantially the entire interior surface.  
         [0006]     An embodiment according to the present invention may also contemplate a method of forming a structural HVAC duct that is defined by a portion of a roof pillar in an automotive vehicle, the method comprising the steps of: (a) providing at least one metal blank; (b) coating a surface of the at least one metal blank with an insulating coating; (c) forming the at least one metal blank into a hollow structural member defining the structural HVAC duct after step (b); and (d) assembling the roof pillar to the automotive vehicle.  
         [0007]     An advantage of an embodiment of the present invention is that the structurally integrated HVAC duct provides a path for directing air flow without requiring the expense of fabricating and assembling an extra duct to provide this flow path.  
         [0008]     Another advantage of an embodiment of the present invention is that the structurally integrated HVAC duct saves space in vehicles having a pillar with a severe bend since a separate duct does have to be mounted outside of the vehicle pillar.  
         [0009]     An additional advantage of an embodiment of the present invention is that the structurally integrated HVAC duct provides an insulating effect to assure that the temperature of the air flowing through the duct is substantially maintained. 
     
    
     BRIEF DESCRIPTION OF DRAWINGS  
       [0010]      FIG. 1  is a rear perspective view of a portion of an automotive vehicle, in accordance with the present invention.  
         [0011]      FIG. 2  is a perspective view of the D-ring portion of the automotive vehicle of  FIG. 1 .  
         [0012]      FIG. 3  is an exploded perspective view of a portion of the D-ring of  FIG. 2 .  
         [0013]      FIG. 4  is a schematic cross section view of coated sheet metal that is employed to form the structural HVAC duct illustrated in  FIG. 3 .  
         [0014]      FIG. 5  is a schematic cross section through the structural HVAC duct of  FIG. 3 .  
         [0015]      FIG. 6  is an exploded perspective view similar to  FIG. 3 , but illustrating a second embodiment of the present invention.  
         [0016]      FIG. 7  is a schematic cross section view of a coated tube that is employed to form the structural HVAC duct illustrated in  FIG. 6 .  
         [0017]      FIG. 8  is a schematic cross section through the structural HVAC duct of  FIG. 6 . 
     
    
     DETAILED DESCRIPTION  
       [0018]      FIGS. 1-3  illustrate a vehicle, indicated generally at  10 , and portions thereof, in accordance with a first embodiment of the present invention. The vehicle  10  has a vehicle body  12  with a floor  14  and a roof  16  that define a vehicle interior. The frame also includes A-pillars  18 , B-pillars (not shown), C-pillars  22 , and D-pillars  24  that support the roof  16 . The D-pillars  24  are part of a D-ring  26 , which defines the rear and rear opening of the body  12 .  
         [0019]     The D-ring  26  includes a lower outer D-ring member  28  and a lower inner D-ring member  30  that define a lower portion  31  of the D-ring  26 . An upper outer D-ring member  32 , an upper inner D-ring member  34 , a left upper reinforcement member  36 , and a right upper body reinforcement member  38  define an upper portion  39  of the D-ring  26 . A left inner pillar D-ring member  40 , a left inner pillar D-ring panel  42 , and a left outer pillar D-ring member  44  define a left side of the D-ring  26 , as well as forming the left pillar  46  of the D-pillars  24 . A right inner pillar D-ring member  48 , a right inner pillar D-ring panel  50 , and a right outer pillar D-ring member  52  define a right side of the D-ring  26 , as well as forming the right pillar  54  of the D-pillars  24 .  
         [0020]     The right pillar  54  and a portion of the upper portion  39  of the D-ring  26  also defines a structural HVAC duct  56  (Shown in  FIG. 5 ). The term structural, as used herein, means that the particular component or components are load bearing or otherwise provide some type of support for the vehicle body. This HVAC duct  56  is a hollow closed section extending through the right D-pillar  54  and part of the way through the upper portion  39 . The hollow space is employed to direct warm/cool air there through. A lower open end of the HVAC duct  56  may be in fluid communication with a portion of an auxiliary HVAC unit (not shown) mounted in a side wall (not shown) near a rear wheel well  60  of the vehicle  10 . An upper open end of the HVAC duct  56  is typically in fluid communication with a duct/vent (not shown) that extends under the roof  16  and directs air flow into the vehicle interior. The vehicle structural members that combine to form the structural HVAC duct  56  include an insulating coating  64  covering their interior surfaces  66 , as is shown and will be described in more detail with reference to  FIGS. 4 and 5 . For this embodiment, all or portions of the interior surfaces of the right inner pillar D-ring member  48 , the right inner pillar D-ring panel  50  and the right outer pillar D-ring member  52 , as well as the upper outer D-ring member  32  and the upper inner D-ring member  34 , would be coated with the insulating coating  64 .  
         [0021]      FIG. 4  is a schematic illustration of a pair of blanks  68 . The blanks  68  may be formed from, for example, a metal such as steel. The blanks  68  illustrate the sheet metal that may be used to form the structural members that combine to define the structural HVAC duct. Each of the blanks  68  is coated on one surface with the insulating coating  64 , which is preferably applied prior to stamping and assembly operations. It is preferably applied prior to these operations because the structural HVAC duct  56  is a closed section and may include severe bends, which would make application of an insulating coating much more difficult after the HVAC duct  56  is formed. The insulating coating  64  can be, for example, a polyester urethane solvent based coating. This material is particularly suited for use as the insulating coating  64  since it provides a good insulating effect while also having the flexibility needed during the part forming process and the temperature resistance needed when the vehicle frame is being subjected to a high temperature oven bake. Alternatively, if reduced cost is a more significant factor than flexibility of the material during forming, the insulating coating  64  may be formed from a polyester melamine coating. Other examples of alternative materials for the insulating coating  64  may be a flexible phenolic, an epoxy-based coating, an acrylic-based coating, or a suitable cross-linked, thermoset material with the desired insulating properties.  
         [0022]      FIG. 5  shows a schematic cross section of the structural HVAC duct  56  that results from the forming and assembly operations performed on the blanks  68  of  FIG. 4 . Each of the blanks  68  is formed into one of the D-ring members through, for example, a stamping operation. The formed portions are then assembled and secured together into a closed section that has the insulating coating  64  covering essentially the entire interior surface  66 . The formed portions may be secured together as part of the D-ring and vehicle body by, for example, spot welding, laser welding, adhesives, rivets, or other suitable attachment methods. Thus, a structural HVAC duct  56  is formed having the insulating coating  64  to minimize the thermal transfer through the wall of the structural HVAC duct  56 . In the alternative, the insulating coating  64  may be applied inside the structural HVAC duct  56  after the forming or assembly operations.  
         [0023]      FIG. 6  illustrates a D-ring  126 , according to a second embodiment of the present invention, that may be employed with the vehicle of  FIG. 1 . The elements in this embodiment are similar to the first, except that some are preferably formed by a hydroforming process rather than a stamping process. Thus, in this embodiment, elements that are similar to those in the first embodiment will be similarly designated, but with 100-series numbers.  
         [0024]     The D-ring  126  includes a lower outer D-ring member  128 , a lower D-ring hydroformed member  133 , and a lower inner D-ring member  130  that define a lower portion of the D-ring  126 . An upper outer D-ring member  132 , a first portion  135  of an upper D-ring hydroform member  134 , a left upper reinforcement member  136 , and a right upper body reinforcement member  138  define an upper portion of the D-ring  126 . A second portion  143  of the upper D-ring hydroform member  134  and a left outer pillar D-ring member  144  define a left side of the D-ring  126 , as well as forming the left pillar of the D-pillars. A third portion  151  of the upper D-ring hydroform member  134 , and a right outer pillar D-ring member  152  define a right side of the D-ring  126 , as well as forming the right pillar of the D-pillars.  
         [0025]     In this embodiment, the structural HVAC duct  156  is defined by the third portion  151  and part of the first portion  135  of the upper D-ring hydroform member  134 . This structural HVAC duct  156  is again a hollow closed section where the hollow space is employed to direct warm/cool air. As with the first embodiment, a lower open end may be in fluid communication with a portion of an auxiliary HVAC unit (not shown) that may be mounted in, for example, a side wall (not shown) near a rear wheel well of the vehicle (shown in  FIG. 1 ). An upper open end may be in fluid communication with a duct/vent (not shown) that extends under the roof and directs air flow into the vehicle interior. The structure that defines the structural HVAC duct  156  includes an insulating coating  164  covering the interior surface  166 , as is shown and will be described in more detail with reference to  FIGS. 7 and 8 . As with the first embodiment, the insulating coating  164  minimizes the thermal transfer through the wall of the duct  156 .  
         [0026]      FIG. 7  is a schematic illustration of a tubular blank  168 , which may be formed from, for example, a metal such as steel. Preferably, a sheet material—prior to making the tubular blank  168 —is coated on one side with the insulating coating  164 . The insulating coating  164  may be similar to those examples suggested with reference to the first embodiment. The sheet material is then formed into the tubular blank  168  and secured by, for example, welding. Thus, the tubular blank  168  will include the insulating material  164  on its interior surface  166 .  
         [0027]      FIG. 8  shows a schematic cross section of the structural HVAC duct  156  that results from a hydroforming operation performed on the blank  168  of  FIG. 7 . Preferably, for a hydroforming operation when the duct  156  includes sever bending, care is taken in selecting the mandrel material and clearance between the mandrel (not shown) and the inside dimensions of tubular blank  168 . This will assure that the hydroforming operation will not adversely affect the insulating coating  164 . In the alternative, the insulating coating  164  may be applied inside the structural HVAC duct  156  after the hydroforming operation. The formed closed section has the insulating coating  164  covering essentially the entire interior surface  166 , thus providing a thermal barrier for air flowing through it.  
         [0028]     Even though the example embodiments discussed herein are directed to a structural HVAC duct defined by structure of the D-pillar, other hollow closed section body members may form the HVAC duct having the insulating material coating therein. For example, the structural HVAC duct with insulating material can form a part of one of the other roof pillars, such as a C-pillar of the vehicle. Thus, while certain embodiments of the present 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 invention as defined by the following claims.