Abstract:
A blower assembly including a housing for a first scroll fan and a second scroll fan that are connected by a shaft to a motor that rotates the fans. The first and second scroll fans are coaxially mounted on the shaft. Fresh air ports and recirculated air ports are provided for the circulation of fresh air and recirculated air, respectively. The fresh air ports and recirculated air ports may be selectively opened and closed by doors to control the flow of air from the outside and from the passenger compartment as controlled by the HVAC system.

Description:
TECHNICAL FIELD 
       [0001]    This disclosure relates to vehicle heating ventilation and air conditioning (HVAC) system blower fans and blower housings. 
       BACKGROUND 
       [0002]    Vehicle HVAC systems have a separate air inlet for fresh air and for recirculated air. Air is directed from the fresh air inlet and/or the recirculated air inlet to the blower within the blower housing. The blower housing structurally supports the blower fan. Blower housings with separate fresh air inlets and recirculated air inlets may encounter problems relating to noise levels and vibration. 
         [0003]    Another problem encountered by vehicle HVAC systems is that they tend to be bulky. As the volume of air moved through the system is increased, the space required to house the blower housing also increases. Space available for a blower housing in a vehicle is limited and may impact vehicle design freedom. 
         [0004]    In HVAC systems having more than one fan, each fan typically has one inlet that is shifted between a fresh air source and a recirculation air source. Multiple fans are not used to draw fresh air and recirculated air through the same inlet. 
         [0005]    The above problems and other problems are addressed by this disclosure as summarized below. 
       SUMMARY 
       [0006]    This disclosure is directed to a HVAC housing for a dual wheel/dual scroll fan blower that is assembled to a blower housing to create a coaxial air flow path within the blower housing. The blower housing may have integral internal ribs that direct air flow from the cowl air flow inlet and indirectly to the blower. The internal rib design in the coaxial fan chamber also provides structural support for directly assembling the fans, motor and other components to the blower housing assembly. The internal rib design reduces noise and vibrations while improving the flow of air into the blower inlet. 
         [0007]    In one embodiment, the fresh air from the cowl air flow inlet may be the only fresh air inlet that provides fresh air to both fans. Fresh air may be provided to two more inlet openings from the cowl area to the fans. Recirculation air inlets may also be provided that may operate in combination with or independently of the fresh air inlets. 
         [0008]    The dual wheel/dual scroll fan blower may be horizontally oriented, vertically oriented or oriented in any angular orientation required to meet the packaging requirements in the limited space available for the HVAC blower housing assembly in a vehicle. The size of the HVAC blower housing assembly may be reduced due to increased efficiency of the coaxial fans and, as a direct result, the size and weight of the instrument panel may be reduced. A smaller HVAC blower housing assembly allows more design freedom for instrument panel designs. 
         [0009]    The HVAC blower housing assembly may facilitate providing a partial recirculation strategy that permits part of the air flow to be recirculated with fresh air. Partial recirculation of air within the vehicle in combination with limited fresh air may reduce the load on the HVAC system and may permit system specifications to be less rigorous. 
         [0010]    According to one aspect of this disclosure, a HVAC blower housing assembly is disclosed that includes a housing and a motor assembled to the housing. A first fan and a second fan are operatively connected to the motor and are coaxially aligned to draw air from a first inlet and a second inlet, respectively. An outlet receives air from the first fan and the second fan and forces the air to the passenger compartment. 
         [0011]    According to another aspect of this disclosure, a HVAC blower housing assembly is disclosed that includes a housing that defines a first opening and a second opening. A motor is disposed within the housing and is connected to a first blower scroll fan and a second blower scroll fan. The first blower scroll fan is operatively connected to the motor that draws air through the first opening. The second blower scroll fan is operatively connected to the motor that draws air through the second opening. A first closure member controls the flow of air through the first opening by controlling the volume of air drawn from a fresh air source and the volume of air drawn from a passenger compartment. A second closure member controls the flow of air through the second opening from the passenger compartment. 
         [0012]    According to further aspects of this disclosure, the HVAC blower housing assemblies summarized above may also include a jacket that defines an annulus disposed around the housing that facilitates air flow around the housing from one end of the housing to the opposite end of the housing. A wide variety of fresh air and recirculated air inlets are disclosed. Different door combinations may be provided to control the sources of air provided to the blower scroll fans. The blower scroll fans are coaxially aligned and may be oriented vertically, horizontally or in another orientation to suit packaging requirements and space limitations within an instrument panel. 
         [0013]    The above aspects of this disclosure and other aspects will be more fully described in the following detailed description of the illustrated embodiments and with reference to the attached drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0014]      FIG. 1  is a cross-sectional view of a HVAC blower housing assembly having recirculation air inlets on both ends of the assembly and a fresh air inlet on one ends of the assembly that also provides fresh air through a partial annulus to the opposite end of the assembly. 
           [0015]      FIG. 2  is a diagrammatic cross-sectional view taken along the line  2 - 2  in  FIG. 1 . 
           [0016]      FIG. 3  is a cross-sectional view of a HVAC blower housing assembly having recirculation air inlets on both ends of the assembly and a fresh air inlet on one end of the assembly that also provides fresh air through a cylindrical annulus to the opposite end of the assembly. 
           [0017]      FIG. 4  is a cross-sectional view of a vertically oriented HVAC blower housing assembly having recirculation air inlets on both ends of the assembly and fresh air inlets on both ends of the assembly. 
           [0018]      FIG. 5  is a cross-sectional view of a horizontally oriented HVAC blower housing assembly having recirculation air inlets on both ends of the assembly and fresh air inlets on both ends of the assembly. 
       
    
    
     DETAILED DESCRIPTION 
       [0019]    The illustrated embodiments are disclosed with reference to the drawings. However, it is to be understood that the disclosed embodiments are intended to be merely examples that may be embodied in various and alternative forms. The figures are not necessarily to scale and some features may be exaggerated or minimized to show details of particular components. The specific structural and functional details disclosed are not to be interpreted as limiting, but as a representative basis for teaching one skilled in the art how to practice the disclosed concepts. 
         [0020]    Referring to  FIG. 1 , a blower assembly  10  is illustrated that includes a housing  12 . A motor  16  is disposed within the housing and is operatively connected to a first scroll fan  18  and a second scroll fan  20  by a shaft  22 . The first and second scroll fans  18  and  20  are coaxially aligned on the shaft  22  and draw air from opposite ends of the housing because they are oppositely oriented on the shaft  22 . The first scroll fan  18  is connected to a first end  26  of the shaft  22  and the second scroll fan  20  is connected to a second end  28  of the shaft  22 . The motor  16  rotates the shaft  22  to operate the first and second scroll fans  18  and  20 . 
         [0021]    A fresh air port  30  admits fresh air F into the housing  12 . The fresh air F is also selectively provided to the fresh air duct  32 . The fresh air duct  32  is a semi-annular duct that routes air around the first and second scroll fans  18  and  20 . A fresh air door  34  may be shifted between a position blocking the fresh air port  30  and an open position in which fresh air F may be provided to the fresh air duct  32 . A first recirculated air duct  36  provides recirculated air R. A first recirculated air door  38  may be opened and closed to permit or prevent the flow of recirculated air R through the first recirculated air duct  36 . The first recirculated air door  38  may be a pivoting door or a roll film door depending on cost and space requirements. A second recirculated air duct  40  is provided at the opposite or lower end of the housing  12  and an alternate recirculated air duct  42  may also be provided on the housing  12  to permit recirculated air R to flow into housing  12 . A combination door  44  may be moved to a blocking position blocking the second recirculated air duct  40  and the alternate recirculated air duct  42 . The combination door  44  may also be moved to block the flow of fresh air F through the fresh air duct  32 . 
         [0022]    Referring to  FIG. 2 , a diagrammatic representation of the apparatus shown in  FIG. 1  is provided. The first scroll fan  18  is shown disposed within the housing  12 . The fresh air duct  32  is shown to be a semi-annular duct attached to the outside of the housing  12 . The first scroll fan  18  is shown in operation expelling air into an outlet duct  50 . The air in the outlet duct  50  is outlet air that is provided to a passenger compartment  52 . 
         [0023]    Referring to  FIG. 3 , a blower assembly  54  is shown that includes a housing  56 . The blower assembly  54  is attached to a bulkhead  58  by a fastener  60 . A cowl  62  is also shown at one end of the housing  56  that separates the interior of the vehicle (not shown) from the exterior. 
         [0024]    A motor  64  is assembled to the housing  56  and bulkhead  58  by motor mount ribs  66  that operatively support the motor  64  within the housing  56 . A first scroll fan  68  and a second scroll fan  70  are provided on opposite ends of a shaft  72 . The shaft  72  is rotated by the motor  64  to provide air flow by rotation of the scroll fans  68  and  70 . 
         [0025]    A fresh air port  76  is defined by the cowl  62  and the housing  56 . Fresh air F is supplied to the blower housing assembly  54  through the fresh air port  76  when a fresh air door  78  is opened. Fresh air door  78  may be closed to operate the blower housing assembly  54  in a recirculation mode. A fresh air duct  80  is provided that encloses the housing  56 . The fresh air duct  80  may be a cylindrical annulus through which fresh air is permitted to flow from the fresh air port  76  through a plurality of acoustic air flow ribs  82  to the opposite ends of the blower assembly  54 . The acoustic air flow ribs  82  support the housing  56  within the fresh air duct  80  and are constructed to eliminate unwanted noise in the blower assembly  54 . A first recirculated air duct  84  is provided in the fresh air duct  80  adjacent the fresh air port  76 . Recirculated air R is admitted through the first recirculated air duct  84  from the passenger compartment  52  (shown in  FIG. 2 ). The first recirculated air duct  84  may be opened and closed by a first roll film door  86  depending upon whether air is requested to be recirculated through the blower assembly  54 . A second recirculated air duct  88  is provided on the opposite end of the blower assembly  54  from the fresh air port  76 . A second roll film door  90  may be provided that opens and closes the second recirculated air duct  88  to either permit or restrict air from being recirculated by the blower housing assembly  54 . 
         [0026]    Referring to  FIG. 4 , another alternative embodiment of a blower assembly  96  is illustrated. A housing  98  of the blower assembly  96  is attached to a cowl  100  of the vehicle (not shown). 
         [0027]    A first scroll fan  106  and a second scroll fan  108  are attached to opposite ends of a shaft  110 . A motor  102  operates the scroll fans  106  and  108 , as previously described. A first fresh air port  112  is provided through the cowl  100  and may be opened and closed by a first fresh air door  114 . A second fresh air port  116  is provided near the other end of the housing  98  and is adapted to be opened and closed by a second fresh air door  118 . The second fresh air port  116  may receive air from the outer side of the bulkhead (not shown) that is similar to the bulkhead  58  shown in  FIG. 3 . A second fresh air door  118  may be opened and closed to allow fresh air F to flow into the housing  98 . A first recirculated air duct  120  is provided in the housing  98  near the first fresh air port  112 . A first roll film door  122  is provided to open and close the first recirculated air duct  120 . A second recirculated air duct  124  is provided in the opposite end of the housing  98  from the first fresh air port  112 . The second recirculated air duct  124  may be opened and closed by a second roll film door  126 , as previously described. 
         [0028]    Referring to  FIG. 5 , a horizontal blower assembly  130  is illustrated that includes a housing  132  that is adapted to be secured below the cowl  134  of the vehicle (not shown). A motor  136  is operatively connected to a first scroll fan  140  and a second scroll fan  142  by a shaft  144 . 
         [0029]    A first fresh air port  146  is provided in the housing  132  on the left side of  FIG. 5 . The first fresh air port  146  may be opened and closed by rotating a dual function door  148  to open and close the first fresh air port  146 . A second fresh air port  150  may be provided between the cowl  134  and housing  132 . The second fresh air port  150  is adapted to be opened and closed by a second fresh air door  152 . A first recirculated air duct  154  may be provided in the housing  132  to permit air to be recirculated in the passenger compartment  52  (as shown in  FIG. 2 ). The dual door  148  may be used to open and close the first recirculated air duct  154  by rotating the dual door  148  between the position shown in  FIG. 5  in solid lines and a position shown in phantom lines in  FIG. 5 . 
         [0030]    A second recirculated air duct  158  is provided in the opposite end of the housing  132  from the first recirculated air duct  154 . The second recirculated air duct  158  may be opened and closed by a roll film door  160 , as previously described. 
         [0031]    While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the disclosed apparatus and method. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure as claimed. The features of various implementing embodiments may be combined to form further embodiments of the disclosed concepts.