Patent Publication Number: US-2022220974-A1

Title: Blower

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Patent Application No. PCT/JP2020/034498 filed on Sep. 11, 2020, which designated the U.S. and claims the benefit of priority from Japanese Patent Application No. 2019-192075 filed on Oct. 21, 2019. The entire disclosures of all of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a blower. 
     BACKGROUND ART 
     Conventionally, a one-sided suction type centrifugal blower is known, which capable of sucking simultaneously air inside a cabin and air outside the cabin separately from each other. In this type of centrifugal blower, a ventilation passage radially outside of an impeller is divided in an axial direction of the impeller by a partition into an upper passage and a lower passage. A separation tube is provided inside the impeller to separate the air taken in from the outside into the upper passage and the lower passage. 
     SUMMARY 
     According to one aspect of the present disclosure, the blower is configured to suck a first fluid and a second fluid separately at a same time. The blower includes a fluid introducing box, a fan, a casing, a tubular portion, and an upper end portion. The fluid introducing box defines a first inlet through which the first fluid is introduced and a second inlet through which the second fluid is introduced. The fan is configured to suck at least one of the first fluid or the second fluid in an axial direction of the fan and blow the at least one of the first fluid or the second fluid in a radial direction of the fan by rotating about a fan axis. The casing houses the fan. The tubular portion has a part disposed inside the fan and configured to introduce at least one of the first fluid or the second fluid separately into the fan. The upper end portion is connected to one end of the tubular portion in the axial direction and defines an air inlet for introducing at least one of the first fluid or the second fluid into the tubular portion. The casing has a suction port forming portion at one end of the casing in the axial direction and the suction port forming portion defines a suction port for introducing at least one of the first fluid or the second fluid into the fan. The upper end portion is disposed at a position between the suction port forming portion and the fluid introducing box to overlap with both of a part of the suction port and a part of the suction port forming portion in the axial direction. A gap passage is defined between the upper end portion and the suction port forming portion and the gap passage includes a passage inlet. At least one of the first fluid or the second fluid is introduced into the gap passage from the passage inlet and fluids through the gap passage toward a downstream portion of the gap passage that is away from the passage inlet. A distance between the upper end portion and the suction port forming portion in the axial direction at the downstream portion is less than that at the passage inlet. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of a blower according to a first embodiment. 
         FIG. 2  is a schematic plan view illustrating a part of the blower according to the first embodiment. 
         FIG. 3  is a schematic plan view of a separation tube of the blower according to the first embodiment. 
         FIG. 4  is a schematic side view of the separation tube according to the first embodiment. 
         FIG. 5  is a schematic perspective view illustrating a part of the blower according to the first embodiment. 
         FIG. 6  is a cross-sectional view taken along a line VI-VI of  FIG. 3 . 
         FIG. 7  is a cross-sectional view taken along a line VII-VII of  FIG. 3 . 
         FIG. 8  is a cross-sectional view taken along a line VIII-VIII of  FIG. 2 . 
         FIG. 9  is a diagram for explaining a relationship between a filter, an upper end portion, and a suction port of the blower according to the first embodiment. 
         FIG. 10  is a schematic cross-sectional view of a blower according to a second embodiment. 
         FIG. 11  is a diagram for explaining a relationship between a filter, an upper end portion, and a suction port of the blower according to the second embodiment. 
         FIG. 12  is a diagram for explaining a relationship between a filter, an upper end portion, and a suction port of a blower according to a third embodiment. 
         FIG. 13  is a schematic plan view illustrating a part of a blower according to a fourth embodiment. 
         FIG. 14  is a cross-sectional view taken along a line XIV-XIV of  FIG. 13 . 
         FIG. 15  is a schematic cross-sectional view of a separation tube of a blower according to a fifth embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     To begin with, examples of relevant techniques will be described. 
     Conventionally, a one-sided suction type centrifugal blower is known, which capable of sucking simultaneously air inside a cabin (hereinafter, also referred to as internal air) and air outside the cabin (hereinafter, also referred to as external air) separately from each other. In this type of centrifugal blower, a ventilation passage radially outside of an impeller is divided in an axial direction of the impeller by a partition into an upper passage and a lower passage. A separation tube is provided inside the impeller to separate the air taken in from the outside into the upper passage and the lower passage. The separation tube has a plate-shaped upper end portion that defines an air inlet. The upper end portion has a substantially rectangular cross-section. With this configuration, a part of the air from the outside flows into the separation tube through the air inlet of the upper end portion and flows through the impeller into the lower passage. Further, the rest of the air from the outside flows outside of the separation tube without passing through the air inlet of the upper end portion and flows through the impeller into the upper passage. As described above, the centrifugal blower is configured to blow air sucked from one side of the impeller in the axial direction of the impeller separately into the upper passage and the lower passage. 
     By the way, the centrifugal blower includes a casing housing the impeller and the casing has a suction port forming portion defining a suction port for air. A part of the suction port forming portion is covered with the upper end portion. When a part of the suction port forming portion is covered with the upper end portion as described above, a part of air flowing outside of the separation tube flows into a gap passage defined between the upper end portion and the suction port forming portion, and then is sucked into the impeller through the suction port. At this time, the air flowing into the gap passage is gradually sucked into the suction port, thus, a downstream portion of the gap passage that is away from the passage inlet has a region where there is almost no airflow. As a result, a stagnation of airflow is generated in the region. Thus, the pressure loss in the gap passage becomes large, and air suction efficiency of the blower deteriorates. These matters are found by diligent studies by the present inventors. 
     It is an objective of the present disclosure to provide a blower that can suck air efficiently. 
     According to one aspect of the present disclosure, the blower is configured to suck a first fluid and a second fluid separately at a same time. The blower includes a fluid introducing box, a fan, a casing, a tubular portion, and an upper end portion. The fluid introducing box defines a first inlet through which the first fluid is introduced and a second inlet through which the second fluid is introduced. The fan is configured to suck at least one of the first fluid or the second fluid in an axial direction of the fan and blow the at least one of the first fluid or the second fluid in a radial direction of the fan by rotating about a fan axis. The casing houses the fan. The tubular portion has a part disposed inside the fan and configured to introduce at least one of the first fluid or the second fluid separately into the fan. The upper end portion is connected to one end of the tubular portion in the axial direction and defines an air inlet for introducing at least one of the first fluid or the second fluid into the tubular portion. The casing has a suction port forming portion at one end of the casing in the axial direction and the suction port forming portion defines a suction port for introducing at least one of the first fluid or the second fluid into the fan. The upper end portion is disposed at a position between the suction port forming portion and the fluid introducing box to overlap with both of a part of the suction port and a part of the suction port forming portion in the axial direction. A gap passage is defined between the upper end portion and the suction port forming portion and the gap passage includes a passage inlet. At least one of the first fluid or the second fluid is introduced into the gap passage from the passage inlet and fluids through the gap passage toward a downstream portion of the gap passage that is away from the passage inlet. A distance between the upper end portion and the suction port forming portion in the axial direction at the downstream portion is less than that at the passage inlet. 
     As described above, when the distance between the upper end portion and the suction port forming portion in the axial direction at the downstream portion is less than that at the passage inlet, a useless area where there is almost no airflow is less likely to occur in the downstream portion. Further, the upper end portion serves as a guide that guides the air toward the suction port in the gap passage. 
     Therefore, according to the blower of the present disclosure, it is possible to suck air more efficiently than the conventional blower. 
     Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, portions that are the same as or equivalent to those described in the preceding embodiments are denoted by the same reference numerals, and a description of the same or equivalent portions may be omitted. In addition, when only a part of the components is described in the embodiment, the components described in the preceding embodiment can be applied to other parts of the components. 
     The following embodiments may be partially combined with each other unless such combination causes a disadvantage, even if it is not explicitly described. 
     First Embodiment 
     The present embodiment will be described with reference to  FIGS. 1 to 9 . In the present embodiment, an example in which a blower  1  of the present disclosure is applied to a two-layer internal/external air conditioner for a vehicle will be described. The blower  1  is arranged inside an instrument panel at the front part of a vehicle compartment. 
     As shown in  FIG. 1 , the blower  1  includes an internal-external air box  10 , a filter  20 , a fan  30 , an electric motor  40 , a scroll casing  50 , and a separation tube  70 . The arrows indicating up/down, front/rear, and left/right in each drawing indicate the up-down direction DR 1 , the front-rear direction DR 2 , and the right-left direction DR 3  when the blower  1  is mounted on the vehicle. 
     The internal-external air box  10  is arranged in an upper portion of the blower  1 . The upper surface of the internal-external air box  10  defines an external air introducing port  11  for introducing external air, a first internal air introducing port  12  for introducing internal air, and a second internal air introducing port  13  for introducing internal air in order from the front side in the front-rear direction DR 2 . With such configuration, external air is easily introduced into the internal-external air box  10  from the outside of the vehicle compartment and internal air is easily introduced into the internal-external air box  10  from the inside of the vehicle compartment. 
     The internal-external air box  10  defines, therein, a first introducing space  101  into which external air from the external air introducing port  11  or internal air from the first internal air introducing port  12  is introduced and a second introducing space  102  into which internal air from the second internal air introducing port  13  is introduced. The first introducing space  101  and the second introducing space  102  are in fluid communication with each other through a communication passage  103 . 
     Inside the internal-external air box  10 , a first internal-external door  14  and a second internal-external door  15  is arranged. The first internal-external door  14  is configured to selectively open and close the external air introducing port  11  and the first internal air introducing port  12 . The second internal-external door  15  is configured to selectively open and close the second internal air introducing port  13  and the communication passage  103 . Each of the first internal-external door  14  and the second internal-external door  15  is configured as a rotary door. The first internal-external door  14  and the second internal-external door  15  may be configured as a door other than the rotary door. The internal-external air box  10  enables the blower  1  to separately suck internal air and external air at the same time. 
     In the present embodiment, the external air introducing port  11  corresponds to a first introducing port through which external air as a first fluid is introduced, and the first internal air introducing port  12  and the second internal air introducing port  13  correspond a second introducing port through which internal air as a second fluid is introduced. Further, in the present embodiment, the internal-external air box  10  corresponds to a fluid introducing box. 
     The filter  20  is arranged below the internal-external air box  10 . The filter  20  is arranged to be substantially parallel to the horizontal direction (for example, the front-rear direction DR 2 ). The filter  20  filters the air introduced from the internal-external air box  10  and collects foreign matters. Each of the internal-external air box  10  and the filter  20  has a rectangular shape in a top view. 
     The fan  30  is a centrifugal fan that sucks air from one side of the blower  1  in an axial direction of the fan  30  and blows out the sucked air in a radial direction away from the fan axis CL of the fan  30 , which is a rotational axis. The fan  30  is formed of a sirocco fan. The fan  30  is not limited to a sirocco fan and may be formed of a radial fan or a turbofan. 
     Here, the axial direction of the fan  30  is a direction extending along the fan axis CL. Further, the radial direction of the fan  30  is perpendicular to the fan axis CL and extends radially about the fan axis CL. The blower  1  of the present embodiment is arranged so that the axial direction of the fan  30  is substantially parallel to the up-down direction DR 1 . Hereinafter, the axial direction of the fan  30  is referred to as a fan axial direction, and the radial direction of the fan  30  is referred to as a fan radial direction. 
     The fan  30  has a plurality of first blades  31 , a plurality of second blades  32 , a main plate  33 , and a separation plate  35 . The first blades  31  are arranged around the fan axis CL. Between the first blades  31 , first blade passages  310  through which air flows are defined. The second blades  32  are arranged around the fan axis CL. The second blades  32  are disposed on a side of the first blades  31  opposite to the internal-external air box  10  in the fan axial direction. Between the second blades  32 , second blade passages  320  through which air flows are defined. 
     The main plate  33  is formed of a disk-shaped member and its center is on the fan axis CL. The main plate  33  includes, in the center thereof, a boss  331  to which a shaft  42  of the electric motor  40  is connected not to rotate relative to each other. The lower end portions of the second blades  32  are fixed to the outer portion of the main plate  33  in the radial direction of the fan  30 . 
     The separation plate  35  is a member that connects between the first blades  31  and the second blades  32 . The separation plate  35  inhibits air flowing through the first blade passages  310  between the first blades  31  from being mixed with air flowing through the second blade passages  320  between the second blades  32 . The separation plate  35  has a ring shape about the fan axis CL, and is formed of a plate-shaped member whose plate surface extends to intersect the fan axis CL. The lower end portions of the first blades  31  are fixed to a first plate surface of the separation plate  35 , and the upper end portions of the second blades  32  are fixed to a second plate surface of the separation plate  35 . The first plate surface and the second plate surface face in the fan axial direction. 
     The fan  30  configured in this way is formed as an integrally molded product in which the first blades  31 , the second blades  32 , the main plate  33 , and the separation plate  35  are integrally molded by a molding technique such as injection molding. 
     The electric motor  40  is configured to rotate the fan  30 . The electric motor  40  has a main body  41  that generates power for rotating the fan  30 , and the shaft  42  that is rotated by the power of the main body  41 . 
     The shaft  42  extends from the main body  41  toward one side in the fan axial direction. The shaft  42  is fixed to the main plate  33  of the fan  30  by a motor cap  43 . As a result, when the shaft  42  rotates, the fan  30  rotates. 
     The scroll casing  50  is a casing housing the fan  30 . The scroll casing  50  rectifies the airflow blown out radially outward from the fan  30  into a flow in the circumferential direction of the fan  30 . The scroll casing  50  forms a spiral ventilation passage  51  on the outer side of the fan  30  in the radial direction. 
     As shown in  FIG. 2 , the scroll casing  50  has a nose portion Ps and an end portion Pe. A scroll diameter rs that is a distance between the fan axis CL and an outer circumferential wall of the scroll casing  50  is minimum at the nose portion Ps and maximum at the end portion Pe. The nose portion Ps is a start point of the ventilation passage  51  and a passage area of the ventilation passage  51  is minimum at the nose portion Ps. The end portion Pe is an end point of the ventilation passage  51  and the passage area of the ventilation passage  51  is maximum at the end portion Pe. 
     An outlet passage portion  53  defining a discharge passage  52  for discharging air toward an air conditioner unit of a vehicular air conditioner (not shown) is fluidly connected to the end portion Pe. As a result, the air flowing inside the scroll casing  50  is introduced into the air conditioning unit. 
     Although not shown, the air conditioning unit adjusts the air introduced from the blower  1  to a desired temperature and blows it into the vehicle compartment. The air conditioning unit is configured to adjust the air introduced from the blower  1  to a desired temperature with a heat exchanger such as an evaporator or a heater core. 
     Referring back to  FIG. 1 , the scroll casing  50  includes a suction port forming portion  60  in an upper portion of the scroll casing  50  that is on one side of the fan  30  in the fan axial direction. The suction port forming portion  60  forms an upper end surface of the scroll casing  50 . The suction port forming portion  60  defines, at its substantially central area, a suction port  61  through which air is sucked into the fan  30 . 
     The suction port forming portion  60  has a bell mouth  62  at an edge of the suction port  61 . The bell mouth  62  guides the air into the suction port  61 . The bell mouth  62  has an arc-shaped cross-section such that the air smoothly flows into the suction port  61 . As a result, the air that has passed through the filter  20  is sucked into the fan  30  through the bell mouth  62 . 
     To the suction port forming portion  60 , an attachment frame  63  for connecting the internal-external air box  10  and the filter  20  are attached. The internal-external air box  10  and the filter  20  are attached to the attachment frame  63 . 
     Inside the scroll casing  50 , a partition  55  for partitioning the ventilation passage  51  and the discharge passage  52  in the up-down direction into a first ventilation passage  531  and a second ventilation passage  532 . The partition  55  is arranged at a position corresponding to the separation plate  35  of the fan  30 . The partition  55  is, for example, arranged to overlap with the separation plate  35  in the radial direction of the fan  30 . As a result, the air having passed through the first blade passages  310  flows into the first ventilation passage  531 . Further, the air having passed through the second blade passages  320  flows into the second ventilation passage  532 . 
     The separation tube  70  is a tubular member extending in the fan axial direction. The separation tube  70  is open at both ends in the fan axial direction. The air to pass through the suction port  61  is divided by the separation tube  70  into an inside air flowing inside of the separation tube  70  and an outside air flowing outside of the separation tube  70 . 
     The separation tube  70  has a tubular portion  72  having a part disposed inside the fan  30  and an upper end portion  71  disposed on one side of the tubular portion  72  in the fan axial direction. The upper end portion  71  and the tubular portion  72  are configured as an integrally molded product. 
     The upper end portion  71  defines an air inlet  710  for introducing air into the tubular portion  72 . The air inlet  710  opens below the second introducing space  102  of the internal-external air box  10  so that the air having been introduced into the second introducing space  102  of the internal-external air box  10  flows into the air inlet  710 . 
     The upper end portion  71  is arranged at a position between the suction port forming portion  60  and the internal-external air box  10  to overlap with both of a part of the suction port  61  and a part of the suction port forming portion  60 . The upper end portion  71  covers a substantially half of each of the suction port  61  and the bell mouth  62 . Specifically, the upper end portion  71  covers an overlapping part of the suction port  61  with the second introducing space  102  in the up-down direction DR 1  and an overlapping part of the bell mouth  62  with the second introducing space  102  in the up-down direction DR 1 . 
     As shown in  FIG. 3 , the upper end portion  71  has a substantially rectangular outer shape when viewed from one side of the fan  30  in the fan axial direction. Further, as shown in  FIG. 4 , at least a part of the upper end portion  71  has a plate shape such that an outer shape of the upper end portion  71  viewed in the radial direction of the fan  30  has a thickness in the fan axial direction. 
     The upper end portion  71  has three edge portions  711 ,  712 ,  713  in contact with the attachment frame  63  of the suction port forming portion  60 , and an outer edge portion  714  that overlaps with the suction port  61  in the fan axial direction. The outer edge portion  714  is not in contact with the attachment frame  63 . 
     The tubular portion  72  is connected to the upper end portion  71 . The tubular portion  72  includes an upper portion  721  connected to the upper end portion  71  and a lower portion  722  disposed inside the scroll casing  50 . The upper portion  721  and the lower portion are tilted relative to the fan axial direction. 
     The tubular portion  72  is tilted relative to the fan axial direction so that an axis at a lower end portion of the upper portion  721  that is connected to the upper end portion  71  intersects the fan axis CL. Further, the lower portion  722  of the tubular portion  72  extends in the radial direction in a direction away from the tubular portion  72 . At the lower end of the lower portion  722 , an air outlet  720  through which the air flows out of the separation tube  70  is defined. 
     The lower end of the lower portion  722  is arranged at a position corresponding to the separation plate  35  of the fan  30 . The lower end of the lower portion  722  is arranged, for example, to overlap with the separation plate  35  in the radial direction of the fan  30 . As a result, the inside air flowing inside of the separation tube  70  flows into the second blade passages  320  of the fan  30 . Further, the outside air flowing outside of the separation tube  70  flows into the first blade passages  310  of the fan  30 . 
     The separation tube  70  is configured such that the air inlet  710  and the air outlet  720  partially overlap each other in the fan axial direction. Specifically, the separation tube  70  has a shape so that at least a part of the outer edges of the air inlet  710  can be visually recognized when the separation tube  70  is viewed from the air outlet  720 . 
     Here, as shown in  FIG. 5 , a gap passage  80  is defined between the upper end portion  71  and the suction port forming portion  60 . The gap passage  80  is a space defined by the suction port forming portion  60 , the attachment frame  63 , and the upper end portion  71 . A part of the outside air to pass through the outside of the separation tube  70  flows into the gap passage  80 . In the gap passage  80 , air flows from the outer edge portion  714  toward the edge portion  713  that faces the edge portion  714  of the upper end portion  71 . Therefore, the outer edge portion  714  of the upper end portion  71  defines a passage inlet  81  of the gap passage  80 . The edge portion  713  facing the outer edge portion  714  defines a downstream portion of the gap passage  80 . 
     The air that has flowed into the gap passage  80  is gradually sucked into the fan  30  through the suction port  61 . At this time, at the downstream portion of the gap passage  80  that is away from the passage inlet  81 , there is a region with almost no airflow, and stagnation of airflow is likely to generate in this region. Such stagnation of airflow is not preferable because it causes loss. 
     On the other hand, in the blower  1  of the present embodiment, the distance between the upper end portion  71  and the suction port forming portion  60  in the fan axial direction of the fan  30  at the downstream portion is less than that at the passage inlet  81 . 
       FIGS. 6 and 7  are views illustrating the cross-sectional shape of the separation tube  70 . In these figures, the suction port forming portion  60  is illustrated in a dashed line to clearly show a relationship between the upper end portion  71  and the suction port forming portion  60 . As shown in  FIGS. 6 and 7 , the distance L 2  between the upper end portion  71  and the suction port forming portion  60  at the edge portion  713  of the upper end portion  71  that faces the outer edge portion  714  is less than the distance L 1  between the upper end portion  71  and the suction port forming portion  60  at the outer edge portion  714  of the upper end portion  71 . 
     The upper end portion  71  of the present embodiment includes a flat plate portion  715  facing the suction port forming portion  60 . The flat plate portion  715  has a thickness in the fan axial direction of the fan  30 . The upper end portion  71  is arranged so that the plate surface of the plate portion  715  is tilted relative to the opening surface OS of the suction port  61 . The opening surface OS is a virtual surface surrounded by and defined by the outer edge of the suction port  61 . The opening surface OS of the present embodiment is perpendicular to the fan axis CL and is substantially parallel to the virtual line VL perpendicular to the fan axis CL. 
     Specifically, the upper end portion  71  is arranged such that a tilted angle θ between the plate surface of the plate portion  715  and the virtual line VL perpendicular to the fan axis CL is an acute angle. It is desirable that the tilted angle θ is set within a range that is larger than 0° and smaller than 45°, for example. More specifically, it is desirable that the tilted angle θ is set within a range of, for example, 5° to 20°. 
     As described above, the distance between the upper end portion  71  and the suction port forming portion  60  at the edge portion  713  is less than that at the outer edge portion  714 . However, the distance is substantially constant from one of the edge portions  711 ,  712  to the other of the edge portions of the upper end portion  71 . That is, the plate portion  715  of the upper end portion  71  is not tilted relative to the suction port forming portion  60  in the direction from one of the edge portions  711  and  712  toward the other. 
     Further, a seal structure is provided on the edge portion  713  of the upper end portion  71  to suppress air leakage from the upper end portion  71  to the suction port forming portion  60 . This seal structure is realized by labyrinth gaps formed by a protrusion  713   a  protruding from the edge portion  713  of the upper end portion  71  toward the suction port forming portion  60  and a protrusion  64  protruding from the suction port forming portion  60  toward the upper end portion  71 . The protrusion  713   a  of the upper end portion  71  is located radially outward of the protrusion  64  of the suction port forming portion  60 . The seal structure is not limited to the labyrinth gaps, and may be realized by a fitting structure. Further, the seal structure may be realized by a structure in which the protrusion  713   a  of the upper end portion  71  is abutted against the suction port forming portion  60  or a structure in which the protrusion  64  of the suction port forming portion  60  is abutted against the upper end portion  71 . 
       FIG. 8  is a cross-sectional view taken along a line VIII-VIII of  FIG. 2 . As shown in  FIG. 8 , the suction port forming portion  60  has a supporter  65  at an outer side of the bell mouth  62  in the radial direction of the fan  30 . The supporter  65  supports the upper end portion  71 . The supporter  65  protrudes from the plate surface of the suction port forming portion  60  toward the upper end portion  71 . The size of the supporter  65  is set such that the supporter  65  is in contact with the upper end portion  71  in the fan axial direction. The outer shape of the supporter  65  is a truncated cone shape and an end surface of the supporter  65  in contact with the upper end portion  71  is flat. 
     The upper end portion  71  has a supported portion  716  at a position facing the supporter  65 . The supported portion  716  has a flat shape in which the angle defined between the supported portion  716  and the opening surface OC of the suction port  61  is smaller than the angle defined between other portion of the upper end portion  71  and the opening surface OS. Specifically, the supported portion  716  has a flat surface FS that is substantially parallel to the opening surface OS of the suction port  61 . 
     As shown in  FIG. 9 , the distance between the upper end portion  71  and the filter  20  in the fan axial direction increases in a direction away from the passage inlet  81 . That is, the distance L 3  between the filter  20  and the upper end portion  71  in the fan axial direction at the edge portion  713  is greater than that at the outer edge portion  714  of the upper end portion  71 . 
     In contrast, the distance between the opening surface OS of the suction port  61  of the suction port forming portion  60  and the filter  20  is constant. That is, the suction port forming portion  60  is arranged such that the opening surface OS of the suction port  61  is substantially parallel to the filter  20 . 
     The blower  1  configured as described above can be selectively set, as an air suction mode, in an external air mode for introducing external air, an internal air mode for introducing internal air, and an internal-external air mode for separately introducing the external air and the internal air at the same time. 
     The external air mode is a mode for introducing only external air into the internal-external air box  10 . During the external air mode, the blower  1  is controlled to position the first internal-external door  14  at a position opening the external air introducing port  11  and the second internal-external door  15  at a position opening the communication passage. 
     The internal air mode is a mode for introducing only internal air into the internal-external air box  10 . During the internal air mode, the blower  1  is controlled to position the first internal-external door  14  at a position opening the first internal air introducing port  12  and the second internal-external door  15  at a position opening the second internal air introducing port  13 . 
     The internal-external air mode is a mode for introducing both of internal air and external air into the internal-external air box  10 . During the internal-external air mode, the blower  1  is controlled to position the first internal-external door  14  at a position opening the external air introducing port  11  and the second internal-external door  15  at a position opening the second internal air introducing port  13 . 
     In the blower  1  during the internal-external air mode, when the fan  30  is rotated by the electric motor  40 , external air is introduced into the first introducing space  101  through the external air introducing port  11  and internal air is introduced into the second introducing space  102  through the second internal air introducing port  13 . 
     The external air introduced into the first introducing space  101  flows through an area of the filter  20  that is not overlap with the upper end portion  71  in the fan axial direction as shown in a solid line Fao, and then flows outside of the separation tube  70  and is sucked into the first blade passages  310  of the fan  30 . The external air sucked into the first blade passages  310  is blown toward the first ventilation passage  531 . 
     On the other hand, internal air introduced into the second introducing space  102  flows through the separation tube  70  and is sucked into the second blade passages  320  of the fan  30  as shown in arrows Fai. The internal air sucked into the second blade passages  320  is blown toward the second ventilation passage  532 . 
     Although not shown, the external air flowing through the first ventilation passage  531  and the internal air flowing through the second ventilation passage  532  are introduced into the air-conditioning unit from the scroll casing  50 . The temperatures of the external air and the internal air are adjusted respectively to desired values, and then the external air and the internal air are blown toward the vehicle compartment through different outlets. 
     Here, a part of the external air having passed through the filter  20  flows into the gap passage  80  defined between the upper end portion  71  and the suction port forming portion  60 . In the blower  1  of the present embodiment, the distance between the upper end portion  71  and the suction port forming portion  60  in the fan axial direction is less at the downstream portion compared to at the passage inlet  81 . Therefore, a useless region where there is almost no airflow is less likely to occur in the downstream portion. 
     In addition, the air flowing into the gap passage  80  from the passage inlet  81  is guided toward the suction port  61  by the upper end portion  71  when flowing toward the downstream portion of the gap passage  80 . That is, the upper end portion  71  also serves as a guide that guides the air toward the suction port  61  in the gap passage  80 . Therefore, according to the blower  1  of the present embodiment, it is possible to suck air more efficiently than the conventional one. 
     Specifically, the upper end portion  71  has the plate portion  715  that faces the suction port forming portion  60  and that has a thickness in the fan axial direction. The upper end portion  71  is arranged such that the plate surface of the plate portion  715  is tilted relative to the opening surface OS of the suction port  61 . According to this, the distance between the upper end portion  71  and the suction port forming portion  60  in the fan axial direction gradually decreases in a direction away from the passage inlet  81 . Thus, a loss due to a dynamic change of the gap passage  80  is suppressed and the suction efficiency can be improved. 
     In addition, in the blower  1 , the distance between the filter  20  and the upper end portion  71  in the fan axial direction increases in a direction away from the passage inlet  81  of the gap passage  80 . According to this, a pressure loss between the filter  20  and the upper end portion  71  can be suppressed, and the air that has passed through the filter  20  can be efficiently sucked into the tubular portion  72 . Therefore, it is possible to improve the air suction efficiency as compared with the conventional one. 
     Here, the suction port forming portion  60  includes the supporter  65  that supports the upper end portion  71 . The upper end portion  71  includes the supported portion  716  supported by the supporter  65 . The supported portion  716  has a flat shape in which the angle between the supported portion  716  and the opening surface OS of the suction port  61  is less than an angle between another portion of the upper end portion  71  and the opening surface OS. When the supported portion  716  of the upper end portion  71  is supported by the supporter  65  having a flat shape that defines a small angle with the opening surface OS of the suction port  61 , the posture of the upper end portion  71  can be stable. 
     Second Embodiment 
     Next, a second embodiment will be described with reference to  FIGS. 10 and 11 . In this embodiment, the different portions from the first embodiment are mainly described and descriptions of portions similar to the first embodiment will be omitted. 
     As shown in  FIG. 10 , in the blower  1 , the filter  20  is arranged to be slightly tilted relative to the horizontal direction (that is, the front-rear direction DR 2 ). Specifically, the filter  20  is arranged in a posture in which the front portion of the filter  20  in the front-rear direction DR 2  is located above the rear portion of the filter  20  in the front-rear direction DR 2 . 
     The separation tube  70  is arranged such that the plate portion  715  of the upper end portion  71  is not tilted relative to the filter  20 . That is, the plate portion  715  is substantially parallel to the filter  20 . Specifically, the plate portion  715  of the upper end portion  71  is arranged to extend along a surface of the filter  20  through which air flows into and out of the filter  20 . The distance between the upper end portion  71  and the filter  20  in the fan axial direction is substantially constant as a whole. 
     On the other hand, the suction port forming portion  60  is arranged such that the opening surface OS of the suction port  61  is substantially parallel to the horizontal direction, as in the first embodiment. That is, in the blower  1 , the suction port forming portion  60  extends in parallel with the horizontal direction. 
     As shown in  FIG. 11 , in the blower  1 , the distance between the opening surface OS of the suction port  61  and the upper end portion  71  decreases in a direction away from the passage inlet  81 . That is, the distance L 2  between the upper end portion  71  and the suction port forming portion  60  at the edge portion  713  of the upper end portion  71  that faces the outer edge portion  714  is less than the distance L 1  between the upper end portion  71  and the suction port forming portion  60  at the outer edge portion  714 . 
     Further, in the blower  1 , the distance between the opening surface OS of the suction port  61  and the filter  20  decreases in a direction away from the passage inlet  81 . That is, the distance L 5  between the filter  20  and the suction port forming portion  60  at the edge portion  713  of the upper end portion  71  that faces the outer edge portion  714  is less than the distance L 4  between the filter  20  and the suction port forming portion  60  at the outer edge portion  714 . 
     The other configurations are similar to those of the first embodiment. The blower  1  in the present embodiment can achieve the advantages obtained from the common configuration or the equivalent configuration to the first embodiment. 
     In the blower  1  of the present embodiment, the distance between the filter  20  and the upper end portion  71  is substantially constant. Therefore, the blower  1  can be configured more compactly than the one in which a part of the distance between the filter  20  and the upper end portion  71  is large. 
     Modification of Second Embodiment 
     In the second embodiment, the filter  20  and the upper end portion  71  are arranged to be slightly tilted relative to the horizontal direction, and the suction port forming portion  60  is arranged in substantially parallel to the horizontal direction. However, the present disclosure is not limited to this. The blower  1  may be arranged, for example, such that both of the filter  20  and the upper end portion  71  are substantially parallel to the horizontal direction and the suction port forming portion  60  is slightly tilted relative to the horizontal direction. 
     Third Embodiment 
     Next, a third embodiment will be described with reference to  FIG. 12 . In this embodiment, the different portions from the first embodiment are mainly described and descriptions of portions similar to the first embodiment will be omitted. 
     As shown in  FIG. 12 , in the blower  1 , the filter  20  is arranged to be slightly tilted relative to the horizontal direction (i.e., the front-rear direction DR 2 ). Specifically, the filter  20  is arranged in a posture in which the front portion of the filter  20  in the front-rear direction DR 2  is located above the rear portion of the filter  20  in the front-rear direction DR 2 . 
     In the separation tube  70 , the plate portion  715  of the upper end portion  71  is arranged to be tilted relative to the horizontal direction (i.e., the front-rear direction DR 2 ). Specifically, the plate portion  715  of the upper end portion  71  is arranged to be tilted relative to the surfaces of the filter  20  through which air flows in and out. 
     The distance between the filter  20  and the upper end portion  71  increases in a direction away from the passage inlet  81 . That is, the distance L 3  between the filter  20  and the upper end portion  71  at the edge portion  713  that faces the outer edge portion  714  is larger than that at the outer edge portion  714 . 
     On the other hand, the suction port forming portion  60  is arranged such that the opening surface OS of the suction port  61  is substantially parallel to the horizontal direction, as in the first embodiment. That is, in the blower  1 , the suction port forming portion  60  extends in parallel with the horizontal direction. 
     In the blower  1 , the distance between the opening surface OS of the suction port  61  and the upper end portion  71  decreases in a direction away from the passage inlet  81 . That is, the distance L 2  between the upper end portion  71  and the suction port forming portion  60  at the edge portion  713  of the upper end portion  71  that faces the outer edge portion  714  is less than the distance L 1  between the upper end portion  71  and the suction port forming portion  60  at the outer edge portion  714 . 
     Further, in the blower  1 , the distance between the opening surface OS of the suction port  61  and the filter  20  and the distance between the opening surface OS of the suction port  61  and the upper end portion  71  decrease in a direction away from the passage inlet  81 . That is, the distance L 5  between the filter  20  and the suction port forming portion  60  at the edge portion  713  of the upper end portion  71  that faces the outer edge portion  714  is less than the distance L 4  between the filter  20  and the suction port forming portion  60  at the outer edge portion  714 . 
     The other configurations are similar to those of the first embodiment. The blower  1  in the present embodiment can achieve the advantages obtained from the common configuration or the equivalent configuration to the first embodiment. 
     Modification of Third Embodiment 
     In the third embodiment, both of the filter  20  and the upper end portion  71  are arranged to be tilted relative to the horizontal direction, and the suction port forming portion  60  is arranged to be substantially parallel to the horizontal direction. However, the present disclosure is not limited to this. The blower  1  may be arranged, for example, such that one of the filter  20  and the upper end portion  71  is arranged to be substantially parallel to the horizontal direction and the suction port forming portion  60  is arranged to be slightly tilted relative to the horizontal direction. 
     Fourth Embodiment 
     Next, a fourth embodiment will be described with reference to  FIGS. 13 and 14 . In this embodiment, the different portions from the first embodiment are mainly described and descriptions of portions similar to the first embodiment will be omitted. 
     As shown in  FIGS. 13 and 14 , in the blower  1 , the distance between the upper end portion  71  and the suction port forming portion  60  differs in a direction from one of the edge portions  711 ,  712  that are connected to the outer edge portion  714  to the other. 
     Specifically, the plate portion  715  of the upper end portion  71  protrudes downward such that the plate portion  715  is located lower as approaching from the edge portions  711 ,  712  to an intermediate portion  717  between the edge portions  711 ,  712 . As a result, the distance between the upper end portion  71  and the suction port forming portion  60  becomes smaller from the edge portions  711 ,  712  toward the intermediate portion  717 . That is, the distance L 7  between the upper end portion  71  and the suction port forming portion  60  at the intermediate portion  717  is smaller than the distance L 6  between the upper end portion  71  and the suction port forming portion  60  at the edge portion  711 ,  712 . 
     The other configurations are similar to those of the first embodiment. The blower  1  in the present embodiment can achieve the advantages obtained from the common configuration or the equivalent configuration to the first embodiment. 
     In the blower  1  of the present embodiment, the distance between the upper end portion  71  and the suction port forming portion  60  becomes smaller in a direction from the edge portion  711 ,  712  to the intermediate portion  717  between the edge portions  711 ,  712 . According to this, the air flowing through the gap passage  80  is easily guided toward the suction port  61  by the upper end portion  71 , and the air flowing into the gap passage  80  is easily sucked into the suction port  61  efficiently. Therefore, it is possible to improve the air suction efficiency as compared with the conventional one. 
     Modification of Fourth Embodiment 
     In the fourth embodiment, the distance between the upper end portion  71  and the suction port forming portion  60  decreases toward the intermediate portion  717  between the edge portions  711  and  712  from the edge portions  711  and  712 . However, the present disclosure is not limited to this. In the blower  1 , the plate portion  715  may be tilted near the edge portions  711 ,  712  and may be flat near the intermediate portion  717 . 
     Fifth Embodiment 
     Next, a fifth embodiment will be described with reference to  FIG. 15 . In this embodiment, the different portions from the first embodiment are mainly described and descriptions of portions similar to the first embodiment will be omitted. 
     As shown in  FIG. 15 , the upper end portion  71  includes a curved portion  718  that curvedly extends in addition to the plate portion  715  that is a tilted flat member. Specifically, a portion of the upper end portion  71  near the outer edge portion  714  is the plate portion  715  and a portion of the upper end portion  71  near the edge portion  713  that faces the outer edge portion  714  is the curved portion  718 . 
     The curved portion  718  curves such that an angle between the curved portion  718  and the suction port forming portion  60  increases from the outer edge portion  714  toward the edge portion  713 . In other words, the curved portion  718  curves such that a decrease rate of the distance between the curved portion  718  and the suction port forming portion  60  increases from the outer edge portion  714  toward the edge portion  713 . 
     The other configurations are similar to those of the first embodiment. The blower  1  in the present embodiment can achieve the advantages obtained from the common configuration or the equivalent configuration to the first embodiment. 
     Modification of Fifth Embodiment 
     The upper end portion  71  of the fifth embodiment includes the plate portion  715  that is flatly tilted. However, the present disclosure is not limited to this. The upper end portion  71  may be curvedly tilted as a whole. Further, a portion of the upper end portion  71  near the outer edge portion  714  may be the curved portion  718  and a portion of the upper end portion  71  near the edge portion  713  that faces the outer edge portion  714  may be the plate portion  715 . Further, the curved portion  718  may curve such that an angle between the curved portion  718  and the suction port forming portion  60  decreases from the outer edge portion  714  toward the edge portion  713 . The upper end portion  71  may have a stepped shape such that a passage area of the gap passage  80  decreases from the passage inlet  81  of the gap passage  80  toward the downstream portion of the gap passage  80 . 
     Other Embodiments 
     Although the representative embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments and can be variously modified as follows, for example. 
     In the above-described embodiments, the filter  20  is arranged between the internal-external air box  10  and the suction port forming portion  60 , but the blower  1  is not limited to this. In the blower  1 , for example, the filter  20  may be arranged inside the internal-external air box  10 , or the filter  20  may be omitted. 
     In the above-described embodiments, the supported portion  716  of the upper end portion  71  that has a flat shape is supported by the supporter  65  of the suction port forming portion  60 . However, the blower  1  is not limited to this. The blower  1  may have a support structure in which the plate portion  715  of the upper end portion  71  is supported by the supporter  65 . Further, the upper end portion  71  may be supported by the attachment frame  63  instead of the suction port forming portion  60 , for example. 
     In the above-described embodiments, the blower  1  is applied to an internal-external air two layers air conditioner for a vehicle that can blow external air and internal air separately. However, the blower  1  may be applied to another device other than the air conditioner. 
     In the above embodiments, it goes without saying that the components constituting the embodiments are not necessarily indispensable unless otherwise clearly stated or unless otherwise thought to be clearly indispensable in principle. 
     In the above embodiments, when a numerical value such as the number, a numerical value, an amount, or a range of the component of the embodiment is mentioned, the numerical value is not limited to the specified number unless otherwise specified to be indispensable or clearly limited to the specified number in principle. 
     In the above embodiments, when a shape, a positional relationship, or the like of the component or the like is mentioned, the shape, the positional relationship, or the like is not limited to that being mentioned unless otherwise specified or limited to a specified shape, a specified positional relationship, or the like in principle. 
     (Overview) 
     According to the first aspect shown in a part or all of the above embodiments, the separation tube of the blower includes a tubular portion configured to introduce the first fluid and the second fluid separately into the fan and an upper end portion defining an air inlet for introducing at least one of the first fluid or the second fluid into the tubular portion. The upper end portion is disposed at a position between the suction port forming portion and the fluid introducing box to overlap with both of a part of the suction port and a part of the suction port forming portion in the axial direction. A gap passage is defined between the upper end portion and the suction port forming portion and the gap passage includes a passage inlet. At least one of the first fluid or the second fluid is introduced into the gap passage from the passage inlet and fluids through the gap passage toward a downstream portion of the gap passage that is away from the passage inlet. A distance between the upper end portion and the suction port forming portion in the axial direction at the downstream portion is less than that at the passage inlet. 
     According to the second aspect, the upper end portion includes a plate portion facing the suction port forming portion and the plate portion has a thickness in the axial direction. The plate surface of the plate portion is tilted relative to an opening surface of the suction port. 
     According to this, the distance between the upper end portion and the suction port forming portion in the axial direction is decreased in a direction away from the passage inlet of the gap passage. Thus, a loss due to a dynamic change of the gap passage can be avoided and suction efficiency of the blower can be improved. In the present disclosure, “the opening surface” means a virtual surface surrounded and defined by the edge of the suction port. 
     According to the third aspect, a filter for filtering the first fluid and the second fluid introduced from the fluid introducing box is arranged between the fluid introducing box and the upper end portion. The distance between the filter and the upper end portion in the axial direction increases in a direction away from the passage inlet. 
     In this way, when the distance between the filter and the upper end portion increases in a direction away from the passage inlet, a pressure loss between the filter and the upper end portion can be suppressed and the air passing through the filter can be drawn into the tubular portion more efficiently. Therefore, the suction efficiency of the blower can be improved. 
     According to the fourth aspect, a filter for filtering the first fluid and the second fluid introduced from the fluid introducing box is arranged between the fluid introducing box and the upper end portion. The distance between the suction port forming portion and the filter in the axial direction at the downstream portion is smaller than that at the passage inlet. This also improves the air suction efficiency of the blower. 
     According to the fifth aspect, a filter for filtering the first fluid and the second fluid introduced from the fluid introducing box is arranged between the fluid introducing box and the upper end portion. The distance between the filter and the upper end portion in the axial direction increases in a direction away from the passage inlet. The distance between the suction port forming portion and the filter in the axial direction at the downstream portion is smaller than that at the passage inlet. This also improves the air suction efficiency of the blower. 
     According to the sixth aspect, the suction port forming portion includes a supporter supporting the upper end portion. The upper end portion includes a supported portion supported by the supporter. The supported portion has a flat shape such that an angle between the supported portion and an opening surface of the suction port is less than an angle between the opening surface and another portion of the upper end portion other than the supported portion. As described above, when the supporter having a flat shape that defines a small angle with the opening surface of the suction port supports the supported portion, the posture of the upper end portion can be stable.