Patent Publication Number: US-2019170147-A1

Title: Blower unit

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application is a continuation application of International Patent Application No. PCT/JP2017/020245 filed on May 31, 2017, which designated the United States and claims the benefit of priority from Japanese Patent Application No. 2016-166952 filed on Aug. 29, 2016. The entire disclosures of all of the above applications are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to a blower unit. 
     BACKGROUND ART 
     A blower unit is mounted on a vehicle, and includes an electric motor, a fan for drawing air from one side in the axial direction and blowing out the air in the radial direction, and a scroll casing housing the fan and having a spiral air passage. 
     SUMMARY 
     According to an aspect of the present disclosure, a blower unit includes: an electric motor having a rotation shaft; a fan that draws in air from one side in an axial direction of the rotation shaft and blows out the air in a radial direction of the rotation shaft; and a scroll casing housing the fan and having an air passage. The scroll casing has: a recess formed in an upper wall of the scroll casing to define a nose portion where a scrolling of the air passage starts; an air supply part communicating with a downstream side of the air passage in a flow of the air, the air supply part forming an air supply space to supply a part of the air flowing through the air passage to the electric motor; and a communication hole that causes an inside space of the recess and the air passage to communicate with each other without going through the air supply part. The air supply part has an intrusion suppressing portion configured to suppress entry of water into the air supply space. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a schematic perspective view illustrating a blower unit according to a first embodiment. 
         FIG. 2  is a schematic plan view illustrating the blower unit of the first embodiment. 
         FIG. 3  is a cross-sectional view taken along a line III-III in  FIG. 2 . 
         FIG. 4  is a cross-sectional view taken along a line IV-IV in  FIG. 2 . 
         FIG. 5  is a cross-sectional view taken along a line V-V in  FIG. 4 . 
         FIG. 6  is an explanatory diagram illustrating a flow of water accumulated in a recess of the blower unit of the first embodiment. 
         FIG. 7  is a cross-sectional view taken along a line VII-VII in  FIG. 4 . 
         FIG. 8  is an explanatory diagram illustrating a flow of cooling air from an air passage to an air supply part in the blower unit of the first embodiment. 
         FIG. 9  is a schematic cross-sectional view illustrating an air supply part according to a second embodiment. 
         FIG. 10  is a schematic view seen in an arrow direction X in  FIG. 9 . 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination. 
     First Embodiment 
     A first embodiment is described with reference to  FIGS. 1 to 8 . In the present embodiment, a blower unit  10  is applied to a vehicle air conditioner that air-conditions a passenger compartment. It should be noted that an arrow direction DRx in the drawings represents an up-down direction in a state where the blower unit  10  is mounted on the vehicle. 
     The blower unit  10  shown in  FIGS. 1 and 2  generates a flow of air to be blown into the passenger compartment. As shown in  FIG. 3 , the blower unit  10  includes an electric motor  20 , a fan  30 , and a scroll casing  40 . 
     The electric motor  20  rotates the fan  30 . The electric motor  20  has a rotation shaft  22  connected to the fan  30 , and a motor body  24  for rotationally driving the rotation shaft  22 . The electric motor  20  is, for example, a DC motor with a brush. It should be noted that the electric motor  20  is not limited to a DC motor with a brush, and may be a brushless motor, an AC motor, or the like. In  FIG. 3 , the axis center MC, which is the rotation center of the electric motor  20 , is indicated by an alternate long and short dash line. The extending direction of the axis center MC of the electric motor  20  corresponds to the axial direction of the rotation shaft  22 . 
     The bottom surface of the electric motor  20  is covered with the motor cover  26 . The motor cover  26  is connected to the scroll casing  40 . A cooling air passage  28  is defined between the motor cover  26  and the scroll casing  40 , and cooling air Fc for cooling the electric motor  20  flows through the cooling air passage  28 . The cooling air passage  28  guides a part of the flow of air generated by the fan  30  to the electric motor  20  as the cooling air Fc. 
     The fan  30  is an air flow generator that generates a flow of air. As shown by a bold arrow Fa in  FIG. 3 , the fan  30  is a centrifugal fan, such as a sirocco fan, or a turbo fan, that draws in air from one side in the axial direction of the rotation shaft  22  and blows out the air in the radial direction DRy of the rotation shaft  22 . The fan  30  is housed inside the scroll casing  40 . 
     The fan  30  includes plural blades  31  arranged around the axis center MC of the electric motor  20 , a side plate  32  connecting one ends of the blades  31 , and a main plate  33  connecting the other ends of the blades  31 . 
     The side plate  32  is made of an annular member whose center portion is opened. The side plate  32  functions as a suction part for introducing the air sucked from the bell mouth portion  422  of the scroll casing  40  into the fan  30 . 
     The main plate  33  has a boss portion  331  connected to the rotation shaft  22  at the center portion thereof. The main plate  33  has a conical surface shape in which the center portion thereof protrudes toward the side plate  32 . The shape of the main plate  33  may be a round plane. 
     The scroll casing  40  defines the outer shape of the blower unit  10 . The scroll casing  40  is produced by assembling plural components made of resin. Specifically, the scroll casing  40  has an upper part  40 A and a lower part  40 B, and is formed by fastening the upper part  40 A and the lower part  40 B by a fastening member such as screw or snap fitting. 
     As shown in  FIG. 2 , an air passage  400  is formed in a spiral shape, inside of the scroll casing  40 , on the outer side of the fan  30  in the radial direction DRy. The scroll casing  40  has a nose portion  402  that sets the start of the scrolling of the air passage  400 . An upstream side and a downstream side of the air passage  400  communicate with each other through a slight clearance near the nose portion  402 . 
     As shown in  FIG. 1 , the scroll casing  40  includes a bell mouth plate  42  that defines an upper wall, a side wall  44  connected to the bell mouth plate  42 , and a bottom wall  46  connected to the side wall  44  to oppose the bell mouth plate  42 . 
     As shown in  FIG. 3 , the bell mouth plate  42  has an air suction port  421  for sucking air at a position facing the side plate  32  of the fan  30 . The bell mouth plate  42  has the bell mouth portion  422  around a periphery of the air suction port  421 . The inner diameter of the bell mouth portion  422  is gradually increased toward the upstream side in the air flow so that air can flow easily to the air suction port  421 . In the present embodiment, the air suction port  421  and the bell mouth portion  422  correspond to an air intake portion for drawing in air. 
     As shown in  FIGS. 2 and 3 , the bell mouth plate  42  has the recess  423  for forming the nose portion  402 . The recess  423  is recessed from the bell mouth portion  422  of the bell mouth plate  42  toward the bottom wall  46 . 
     The side wall  44  defines an outer shape of the blower unit  10  exposed to the outside in the radial direction DRy of the rotation shaft  22 . The side wall  44  is formed in a spiral shape around the axis center MC of the rotation shaft  22 . 
     The bottom wall  46  forms the air passage  400  together with the bell mouth plate  42  and the side wall  44 . The bottom wall  46  forms the cooling air passage  28  together with the motor cover  26 . A motor holder  461  is attached to the bottom wall  46 , at a position facing the main plate  33  of the fan  30 , and holds the motor body  24  of the electric motor  20 . 
     Water may enter the blower unit  10  from the outside when it is raining, or when the vehicle is washed with water. The water may accumulate in the bell mouth plate  42 . Since the bell mouth plate  42  has the recess  423 , the water tends to accumulate particularly in the recess  423 . 
     In the scroll casing  40  of the present embodiment, a communication hole  424  is provided in the recess  423  such that the air passage  400  and the inner space of the recess  423  communicate with each other. The water accumulated in the recess  423  is discharged to the air passage  400  via the communication hole  424 . As shown in  FIG. 4 , the communication hole  424  is located at a position where the upper part  40 A and the lower part  40 B of the scroll casing  40  are in contact with each other. 
     As shown in  FIG. 2 , the communication hole  424  is positioned downstream of the air passage  400  in the flow of air, in the recess  423 , such that the water discharged into the air passage  400  does not interfere with the fan  30 . Specifically, the communication hole  424  of the present embodiment is formed in a part of the recess  423  not opposing to the fan  30 . 
     In addition, as shown in  FIG. 5 , the communication hole  424  is provided at a lower side of the recess  423  in order to improve the drainage performance from the recess  423 . The size of the communication hole  424  is set to such a size that the air flowing through the air passage  400  is hard to flow back to the inner space of the recess  423  through the communication hole  424 . 
     Further, the scroll casing  40  has a drainage guide groove  425  extending from the communication hole  424  toward the bottom wall  46 . The drainage guide groove  425  is formed as a groove extending in the up-down direction DRx. The drainage guide groove  425  is formed in the lower part  40 B of the scroll casing  40 . 
     Consequently, in the scroll casing  40  of the present embodiment, the water accumulated in the recess  423  is discharged to the air passage  400  via the communication hole  424  as indicated by an arrow FW in  FIG. 6 . The water discharged to the air passage  400  through the communication hole  424  flows toward the bottom wall  46  of the scroll casing  40  along the drainage guide groove  425 . 
     As shown in  FIG. 2 , the scroll casing  40  has an air supply part  50  that defines an air supply space  51  for supplying a part of the air flowing through the air passage  400  to the electric motor  20  via the cooling air passage  28 . The air supply part  50  is provided adjacent to the recess  423  of the bell mouth plate  42  in the radial direction DRy. 
     As shown in  FIGS. 4 and 7 , the air supply part  50  has a supply opening  52  for causing the air passage  400  and the air supply space  51  to communicate with each other. The supply opening  52  is formed in a portion of the air supply part  50  facing the air passage  400 . The supply opening  52  is formed at a position downstream of the communication hole  424  in the flow of air, in the scroll casing  40 . 
     The air supply part  50  has a pipe portion  53  for guiding the air from the air supply space  51  to the cooling air passage  28 . The pipe portion  53  has the upper end opening positioned above the bottom portion of the air supply part  50 , so that the water accumulated in the bottom portion of the air supply part  50  does not flow into the pipe portion  53 . 
     Further, the air supply part  50  has an intrusion suppressing portion  54  for suppressing entry of water into the air supply space  51 . The intrusion suppressing portion  54  has a rib  541  which closes a part of the supply opening  52  located near the communication hole  424 . 
     As shown in  FIG. 7 , the rib  541  protrudes upward from the bottom of the air supply part  50 . The upper end of the rib  541  is separated from the wall surface of the scroll casing  40  so that the supply opening  52  is formed on the upper side of the rib  541 . 
     The rib  541  has a drain hole  541   a  for draining the water accumulated in the air supply space  51  to the air passage  400 . The drain hole  541   a  is formed in a slit shape hole extending in the up-down direction. The drain hole  541   a  is formed in the rib  541  at a position away from the communication hole  424 . 
     As shown in  FIG. 4 , the rib  541  is configured such that the upper end position HU 1  of the rib  541  is located above the upper end position HU 2  of the communication hole  424 . In other words, the communication hole  424  is configured such that the upper end position HU 2  of the communication hole  424  is positioned lower than the upper end position HU 1  of the rib  541 . Therefore, it is possible to suppress the water discharged from the communication hole  424  to the air passage  400  from entering the air supply space  51  together with the air flowing into the air supply space  51 . 
     The drain hole  541   a  is configured such that the lower end position HL 1  of the drain hole  541   a  is located above the lower end position HL 2  of the drainage guide groove  425 . It is possible to suppress the water flowing through the drainage guide groove  425  from entering the air supply space  51  via the drain hole  541   a.    
     Next, the operation of the blower unit  10  of the present embodiment will be described. In the blower unit  10 , the fan  30  is rotated by the rotation of the rotation shaft  22  of the electric motor  20 . As a result, as shown in  FIG. 3 , due to the fan  30 , the air sucked from one side in the axial direction of the rotation shaft  22  is blown out to the air passage  400  in the radial direction DRy. 
     As shown in  FIG. 8 , a part of the air blown into the air passage  400  flows into the air supply space  51  via the supply opening  52  of the air supply part  50 . At this time, since the rib  541  is provided as the intrusion suppressing portion  54  in the supply opening  52 , entry of water existing in the air passage  400  is suppressed. 
     As shown in  FIG. 3 , the air flowing into the air supply space  51  is supplied to the electric motor  20  via the pipe portion  53  and the cooling air passage  28 . As a result, the electric motor  20  is cooled. 
     According to the blower unit  10  of the present embodiment, water accumulated in the recess  423  of the scroll casing  40  is directly discharged to the air passage  400 . Therefore, the water accumulated in the recess  423  does not directly flow into the air supply space  51 . 
     Further, the air supply part  50  has the intrusion suppressing portion  54  for suppressing entry of water from the air passage  400  to the air supply space  51 . Therefore, in the blower unit  10  of the present embodiment, it is possible to suppress the water existing in the air passage  400  from entering the air supply space  51  via the supply opening  52 . 
     Therefore, in the blower unit  10  of the present embodiment, it is possible to appropriately discharge the water accumulated in the recess  423  of the scroll casing  40  to the air passage  400  while suppressing the wetting of the electric motor  20 . 
     Specifically, in the blower unit  10  of the present embodiment, the intrusion suppressing portion  54  is constructed by the rib  541  which closes a part of the supply opening  52  located near the communication hole  424 . In this way, when a part of the supply opening  52  located close to the communication hole  424  is closed by the rib  541 , the water discharged from the communication hole  424  to the air passage  400  can be suppressed from flowing into the air supply space  51  through the supply opening  52 . 
     Further, the rib  541  has the drain hole  541   a  shaped in the slit extending in the up-down direction. As a result, in the blower unit  10  of the present embodiment, even if water enters the air supply space  51  via the supply opening  52 , the water can be drained into the air passage  400  through the drain hole  541   a , so that it is possible to sufficiently suppress the wetting of the electric motor  20 . 
     Furthermore, since the drainage guide groove  425  extending from the communication hole  424  toward the bottom wall  46  is formed in the scroll casing  40 , the water discharged from the communication hole  424  to the air passage  400  easily flows along the drainage guide groove  425  toward the bottom wall  46 . Therefore, in the blower unit  10  of the present embodiment, it is possible to sufficiently suppress the water discharged from the communication hole  424  to the air passage  400  from flowing into the electric motor  20  via the supply opening  52 . 
     Second Embodiment 
     A second embodiment is described with reference to  FIG. 9  and  FIG. 10 . The air supply part  50  of the blower unit  10  of the present embodiment is different from that of the first embodiment.  FIG. 9  is a schematic cross-sectional view in the vicinity of the air supply part  50  of the present embodiment, and corresponds to  FIG. 7  of the first embodiment. 
     As shown in  FIG. 9 , in the present embodiment, the intrusion suppressing portion  54  of the air supply part  50  for suppressing the intrusion of water into the air supply space  51  is constructed of plural ribs  542 ,  543 . Specifically, the intrusion suppressing portion  54  of the present embodiment has a lower rib  542  extending upward from a lower side of the supply opening  52  and an upper rib  543  extending downward from an upper side of the supply opening  52  so that the air supply space  51  has a labyrinth structure. 
     The lower rib  542  closes a part of the supply opening  52  located near the communication hole  424 . Specifically, the lower rib  542  is formed of the same rib as the rib  541  of the first embodiment. 
     The lower rib  542  of the present embodiment, as shown in  FIG. 10 , has a drain hole  542   a  shaped in a slit extending in the up-down direction. Since the drain hole  542   a  is configured similarly to the drain hole  541   a  described in the first embodiment, its description will be omitted. 
     As shown in  FIG. 9 , the upper rib  543  is formed at a position more distanced from the air passage  400  than the lower rib  542  is in the air flowing direction. Specifically, the upper rib  543  is located between the supply opening  52  and the pipe portion  53  in the air flowing direction, in the air supply space  51 . 
     In addition, the lower end of the upper rib  543  is separated from the bottom of the air supply part  50  so that a clearance is formed for the flow of the cooling air. Specifically, the upper rib  543  of the present embodiment is configured such that the lower end position of the upper rib  543  is located lower than the upper end position of the pipe portion  53 . Therefore, water existing in the air supply space  51  can be restricted from entering the pipe portion  53 . 
     The other structures are similar to the corresponding structures of the first embodiment. The blower unit  10  of the present embodiment can obtain the same effect as the blower unit  10  of the first embodiment, which is obtained from the configuration common to the first embodiment. 
     The blower unit  10  of the present embodiment includes the intrusion suppressing portion  54  constructed by the lower rib  542  which extends from the lower side to the upper side and the upper rib  543  which extends from the upper side to the lower side. 
     Therefore, in the blower unit  10  of the present embodiment, the air flowing into the air supply space  51  via the supply opening  52  flows up and down in the air supply space  51  and then passes through the pipe portion  53 . In this way, since the air supply space  51  has a labyrinth structure, the water discharged from the communication hole  424  to the air passage  400  can be sufficiently suppressed from flowing into the electric motor  20  via the air supply space  51 . 
     The lower rib  542  of the present embodiment has the drain hole  542   a  shaped in a slit extending in the up-down direction. As a result, in the blower unit  10  of the present embodiment, even if water enters the air supply space  51  via the supply opening  52 , the water can be drained into the air passage  400  through the drain hole  541   a , so that it is possible to sufficiently suppress the wetting of the electric motor  20 . 
     Other Embodiments 
     Although the representative embodiments have been described above, the present disclosure should not be limited to the above-described embodiments. For example, various modifications can be made as follows. 
     In the first embodiment described above, the intrusion suppressing portion  54  is configured by the rib  541  that closes a part of the supply opening  52  located near the communication hole  424 , but is not limited thereto. For example, the rib  541  of the intrusion suppressing portion  54  may be located away from the communication hole  424  to close a part of the supply opening  52 . 
     As in the first embodiment, it is preferable to form the drain hole  541   a  in the rib  541 , but is not limited thereto. The intrusion suppressing portion  54  may not have the drain hole  541   a  formed in the rib  541 . 
     It is preferable to form the drainage guide groove  425  in the scroll casing  40  as in the first embodiment, but is not limited thereto. The scroll casing  40  may not have the drainage guide groove  425 . 
     In the second embodiment, the intrusion suppressing portion  54  is configured by two ribs, that is, the lower rib  542  and the upper rib  543 , but is not limited thereto. The intrusion suppressing portion  54  may be composed of three or more ribs. Further, the intrusion suppressing portion  54  is not limited to the rib extending in the up-down direction DRx, but may also be a rib extending in a direction intersecting the up-down direction DRx. 
     It is preferable to form the drain hole  542   a  in the lower rib  542  as in the second embodiment, but is not limited thereto. The intrusion suppressing portion  54  may not have the drain hole  542   a  formed in the lower rib  542 . 
     In the respective embodiments, it goes without saying that elements forming the embodiments are not necessarily essential unless specified as being essential or deemed as being apparently essential in principle. 
     In a case where a reference is made to the components of the respective embodiments as to numerical values, such as the number, values, amounts, and ranges, the components are not limited to the numerical values unless specified as being essential or deemed as being apparently essential in principle. 
     Also, in a case where a reference is made to the components of the respective embodiments above as to shapes and positional relations, the components are not limited to the shapes and the positional relations unless explicitly specified or limited to particular shapes and positional relations in principle. 
     Examples of relevant techniques will be described as a comparison example. In a comparison example, an air blowing unit is configured to discharge water accumulated in a recess to an air passage via a space that supplies air to the electric motor. 
     In the comparison example, since water flows in the space for supplying air to the electric motor, the electric motor may be easily wetted. Wetting of the electric motor is not preferable because the wetting causes a damage to the electric motor. 
     In contrast, according to the present disclosure, the blower unit is capable of discharging water accumulated in the recess to the air passage while suppressing the electric motor from being wetted. The blower unit may be mounted on a vehicle. 
     According to one aspect of the present disclosure, the blower unit includes: an electric motor having a rotation shaft; a fan that draws in air from one side in an axial direction of the rotation shaft and blows out the air in a radial direction of the rotation shaft; and a scroll casing housing the fan and having a scroll air passage. 
     The scroll casing has an upper wall having a suction port for drawing in air, a side wall connected to the upper wall, and a bottom wall connected to the side wall to oppose the upper wall. 
     The scroll casing has: a recess formed in the upper wall to define a nose portion that regulates a start of scrolling of the air passage; an air supply part communicating with a downstream side of the air passage in a flow of the air, the air supply part forming an air supply space to supply a part of the air flowing through the air passage to the electric motor; and a communication hole that causes an inside space of the recess and the air passage to communicate with each other without going through the air supply part. The air supply part has an intrusion suppressing portion configured to suppress entry of water into the air supply space. 
     Accordingly, the water accumulated in the recess of the scroll casing is directly discharged into the air passage, so that water entering the recess does not directly flow into the air supply space. Further, the air supply part is provided with the intrusion suppressing portion for suppressing entry of water from the air passage to the air supply space. 
     Therefore, according to the blower unit of the present disclosure, it is possible to discharge the water accumulated in the recess formed in the scroll casing to the air passage while suppressing the wetting of the electric motor. 
     According to the first aspect represented by a part or all of the above embodiments, the blower unit is provided with a communication hole in the scroll casing for communicating the inside space of the recess and the air passage with each other without going through the air supply part. The air supply part is provided with an intrusion suppression unit for suppressing entry of water into the air supply space. 
     According to the second aspect, the air supply space of the blower unit communicates with the air passage via the supply opening formed in the air supply part. The intrusion suppressing portion includes at least one rib that closes a part of the supply opening located near the communication hole. 
     In this way, since the intrusion suppressing portion includes the rib to close a part of the supply opening located near the communication hole, the water discharged from the communication hole to the air passage can be restricted from flowing into the air supply space. 
     According to the third aspect, in the blower unit, the rib has a slit-shaped drain hole extending in the vertical direction. Accordingly, even if water intrudes into the air supply space through the supply opening, the water is drained to the air passage via the drain hole, so that the wetting of the electric motor can be suppressed sufficiently. 
     According to the fourth aspect, the air supply space of the blower unit communicates with the air passage via the supply opening formed in the air supply part. The intrusion suppressing portion includes a lower rib extending from the lower side to the upper side and an upper rib extending from the upper side to the lower side so that the air supply space has a labyrinthine structure. 
     In this way, since the air supply space has a labyrinth structure, it is possible to sufficiently suppress the water discharged from the communication hole to the air passage from flowing into the electric motor via the air supply space. 
     According to the fifth aspect, in the blower unit, the lower rib has a slit-shaped drain hole extending in the vertical direction. Accordingly, even if water intrudes into the air supply space through the supply opening, the water is drained to the air passage via the drain hole, so that the wetting of the electric motor can be suppressed sufficiently. 
     According to the sixth aspect, the blower unit has a drainage guide groove formed in the scroll casing and extending from the communication hole toward the bottom wall. Accordingly, the water discharged from the communication hole to the air passage easily flows toward the bottom wall along the drainage guide groove. Therefore, it is possible to sufficiently suppress the water discharged from the communication hole to the air passage from flowing into the electric motor via the supply opening.