US20250012292A1 - Centrifugal air-sending device and air-conditioning apparatus - Google Patents

Centrifugal air-sending device and air-conditioning apparatus Download PDF

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Publication number
US20250012292A1
US20250012292A1 US18/709,963 US202218709963A US2025012292A1 US 20250012292 A1 US20250012292 A1 US 20250012292A1 US 202218709963 A US202218709963 A US 202218709963A US 2025012292 A1 US2025012292 A1 US 2025012292A1
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United States
Prior art keywords
plate
air
sending device
fan
extension plate
Prior art date
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Pending
Application number
US18/709,963
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English (en)
Inventor
Hiroyasu Hayashi
Takuya Teramoto
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Assigned to MITSUBISHI ELECTRIC CORPORATION reassignment MITSUBISHI ELECTRIC CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TERAMOTO, TAKUYA, HAYASHI, HIROYASU
Publication of US20250012292A1 publication Critical patent/US20250012292A1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/4206—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for elastic fluid pumps
    • F04D29/422—Discharge tongues
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/4206—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for elastic fluid pumps
    • F04D29/4226—Fan casings
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D17/08—Centrifugal pumps
    • F04D17/10—Centrifugal pumps for compressing or evacuating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F24—HEATING; RANGES; VENTILATING
    • F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
    • F24F1/00—Room units for air-conditioning, e.g. separate or self-contained units or units receiving primary air from a central station
    • F24F1/0007—Indoor units, e.g. fan coil units
    • F24F1/0018—Indoor units, e.g. fan coil units characterised by fans
    • F24F1/0022—Centrifugal or radial fans

Definitions

  • the present disclosure relates to a centrifugal air-sending device having a scroll casing and to an air-conditioning apparatus.
  • An existing centrifugal air-sending device includes a fan having a main plate that is disc-shaped, a plurality of blades located around a periphery of the main plate, and a side plate that is located such that the side plate faces the main plate, and fixes the blades. Further, to raise the pressure of airflow generated by the rotation of the fan and flowing out from the blades, the existing centrifugal air-sending device includes a scroll casing that is spiral-shaped, has a tongue portion from which an air trunk starts to be gradually expanded, and guides the airflow to a discharge port.
  • the air trunk is abruptly expanded in the vicinity of the discharge port, there is a difference in direction of the airflow between one portion of the fan that is closer to the main plate than is another portion of the fan that is closer to the side plate than is the one portion and the other portion. Therefore, in the existing centrifugal air-sending device, a portion of the airflow that flows through the other portion closer to the side plate does not flow toward the discharge port but flows backward into the scroll casing while sucking in air from around the discharge port. This may reduce the volume of air and increase noise.
  • the centrifugal air-sending device of Patent Literature 1 when the centrifugal air-sending device of Patent Literature 1 is installed in a narrow space, the distance from the tongue portion to a discharge-port end cannot be lengthened. Therefore, in a state in which the wall thickness of the tongue portion is great as in the case of the centrifugal air-sending device of Patent Literature 1, the centrifugal air-sending device may not be able to raise pressure inside the scroll casing, as the air trunk cannot be sufficiently expanded, and may reduce the volume of air that is discharged, as the discharge port has a narrow opening.
  • the present disclosure is made to solve the above problems and has as an object to provide a centrifugal air-sending device and an air-conditioning apparatus that, even when installed in a narrow space, can raise pressure inside a scroll casing while preventing backflow of airflow in the scroll casing and control a reduction in the volume of air that is discharged.
  • a centrifugal air-sending device includes a fan and a scroll casing.
  • the fan has a main plate that is disc-shaped, a plurality of blades located around a periphery of the main plate, and a side plate that is ring-shaped, is located such that the side plate faces the main plate, and fixes ends of the plurality of blades that are opposite to the main plate.
  • the scroll casing has a peripheral wall that is spiral-shaped and at least one side wall that has a bell mouth that forms an air inlet that communicates with a space surrounded by the main plate and the plurality of blades.
  • the scroll casing forms a discharge port through which airflow generated by the fan is discharged.
  • the scroll casing houses the fan.
  • the scroll casing has a tongue portion and an extension plate.
  • the tongue portion forms a curved surface at a winding-start portion of the peripheral wall that is closer to a rotation axis of the fan than are other portions of the peripheral wall.
  • the tongue portion guides the airflow generated by the fan to the discharge port.
  • the extension plate is plate-shaped, projects from the tongue portion, is spaced apart from the fan, and extends from the tongue portion along an outer periphery of the fan.
  • the extension plate has one portion that is closer to the side plate than is another portion of the extension plate that is closer to the main plate than is the one portion. The one portion is formed longer than the other portion in a circumferential direction of the fan.
  • the extension plate has a distal end portion that extends in a direction of projection in which the extension plate projects from the tongue portion.
  • the distal end portion has an extreme distal end that is located at a boundary between the distal end portion and the at least one side wall.
  • the scroll casing has, in a case in which the scroll casing is projected in an axial direction of the rotation axis, a tongue-portion-side end that is located in a discharge-port edge that is a portion that corresponds to the discharge port.
  • the tongue-portion-side end is an end that is closer to the tongue portion than is another end of the discharge-port edge.
  • the tongue-portion-side end is located opposite to the extreme distal end in the circumferential direction across a reference line drawn perpendicular to the discharge-port edge from the rotation axis.
  • An air-conditioning apparatus includes the centrifugal air-sending device described above and a heat exchanger through which air caused by the centrifugal air-sending device to flow passes.
  • the centrifugal air-sending device has an extension plate that is plate-shaped, projects from the tongue portion, is spaced apart from the fan, and extends from the tongue portion along an outer periphery of the fan.
  • the extension plate has one portion that is closer to the side plate than is another portion of the extension plate that is closer to the main plate than is the one portion.
  • the one portion is formed longer than the other portion in a circumferential direction of the fan.
  • the one portion of the extension plate reduces backflow of the airflow from around the discharge port toward the inside of the scroll casing, whereby the airflow can be smoothly guided from the one portion to the discharge port.
  • the formation of the extension plate in the shape of a plate makes it possible to ensure the distance between the extension plate and the discharge port and sufficiently ensure an air trunk, thus making it possible to surely raise pressure inside the scroll casing.
  • the extension plate has a distal end portion that extends in a direction of projection in which the extension plate projects from the tongue portion.
  • the distal end portion has an extreme distal end that is located at a boundary between the distal end portion and the at least one side wall.
  • the tongue-portion-side end is located opposite to the extreme distal end in the circumferential direction across a reference line drawn perpendicular to the discharge-port edge from the rotation axis. Therefore, the centrifugal air-sending device can ensure the opening area of the discharge port and control a reduction in the volume of air that is discharged.
  • FIG. 1 is a perspective view of a centrifugal air-sending device according to Embodiment 1.
  • FIG. 2 is a side view of the centrifugal air-sending device in FIG. 1 as seen from a discharge port.
  • FIG. 3 is a schematic view of the centrifugal air-sending device according to Embodiment 1 as seen in an axial direction of a rotation axis at a position in the centrifugal air-sending device indicated by line A-A in FIG. 2 .
  • FIG. 4 is a side view of a first modification of the centrifugal air-sending device of Embodiment 1 as seen from a discharge port.
  • FIG. 5 is a side view of a second modification of the centrifugal air-sending device of Embodiment 1 as seen from a discharge port.
  • FIG. 6 is a schematic view of a centrifugal air-sending device according to a comparative example as seen in an axial direction of a rotation axis.
  • FIG. 7 is a side view of the centrifugal air-sending device in FIG. 6 as seen from a discharge port.
  • FIG. 8 is a schematic view of a centrifugal air-sending device according to Embodiment 2 as seen in an axial direction of a rotation axis at a position in the centrifugal air-sending device indicated by line A-A in FIG. 2 .
  • FIG. 9 is a side view of a centrifugal air-sending device according to Embodiment 3 as seen from a discharge port.
  • FIG. 10 is a conceptual diagram of an example of use of the centrifugal air-sending device according to Embodiment 3.
  • FIG. 11 is a side view of a centrifugal air-sending device according to Embodiment 4 as seen from a discharge port.
  • FIG. 12 is a perspective view of an air-conditioning apparatus according to Embodiment 5.
  • FIG. 13 is a schematic view showing an internal configuration of the air-conditioning apparatus according to Embodiment 5.
  • FIG. 1 is a perspective view of a centrifugal air-sending device 1 according to Embodiment 1.
  • FIG. 2 is a side view of the centrifugal air-sending device 1 in FIG. 1 as seen from a discharge port 42 a .
  • FIG. 3 is a schematic view of the centrifugal air-sending device 1 according to Embodiment 1 as seen in an axial direction of a rotation axis RA at a position in the centrifugal air-sending device 1 indicated by line A-A in FIG. 2 .
  • FIG. 3 is also a conceptual diagram in which a scroll casing 4 of the centrifugal air-sending device 1 of Embodiment 1 is projected in the axial direction of the rotation axis RA.
  • a circumferential direction CD indicated by arrows in FIGS. 1 and 3 indicates a circumferential direction of a fan 2 .
  • a basic structure of the centrifugal air-sending device 1 is described with reference to FIGS. 1 to 3
  • the centrifugal air-sending device 1 is a multi-blade centrifugal air-sending device, and includes a fan 2 , which generates airflow, and a scroll casing 4 in which the fan 2 is housed.
  • the centrifugal air-sending device 1 is a double-suction centrifugal air-sending device into which air is sucked through both ends of the scroll casing 4 in an axial direction of the rotation axis RA of the fan 2 , which is virtually drawn.
  • the fan 2 is a centrifugal fan.
  • the fan 2 is connected to a motor (not illustrated) having a drive shaft.
  • the fan 2 is driven into rotation by the motor.
  • the rotation generates a centrifugal force with which the fan 2 forcibly sends out air outward in radial directions.
  • the fan 2 is rotated, for example, by the motor in a direction of rotation R indicated by an arrow.
  • the fan 2 has a main plate 2 a , which is disc-shaped, a side plate 2 c , which is ring-shaped, and a plurality of blades 2 d arranged around a periphery 2 a 1 of the main plate 2 a in a radial manner around the rotation axis RA.
  • the fan 2 is formed in the shape of a circular cylinder by the plurality of blades 2 d arranged on the main plate 2 a .
  • the fan 2 has a fan air inlet 2 e formed in a portion of the fan 2 that is opposite to the main plate 2 a and closer to the side plate 2 c than are other portions of the fan 2 in the axial direction of the rotation axis RA.
  • the fan air inlet 2 e allows gas to flow into a space surrounded by the main plate 2 a and the plurality of blades 2 d.
  • the main plate 2 a needs only be in the shape of a plate, and may for example have a non-disc shape such as a polygonal shape. Further, the main plate 2 a may be formed such that the thickness of the main plate 2 a increases toward the center in a radial directions that start from the rotation axis RA as a radial center, or may be formed such that the thickness is uniform in radial directions that start from the rotation axis RA as a radial center. Further, instead of being formed by one plate-shaped element, the main plate 2 a may be formed by a plurality of plate-shaped elements integrally fixed to each other. It should be noted that the radial directions that start from the rotation axis RA as a radial center are each a direction perpendicular to the axial direction of the rotation axis RA.
  • a boss portion 2 b to which the drive shaft of the motor is connected is provided at a central part of the main plate 2 a .
  • the boss portion 2 b has a shaft hole into which the drive shaft of the motor is inserted.
  • the boss portion 2 b is formed in a circular columnar shape, the shape of the boss portion 2 b is not limited to the circular columnar shape.
  • the boss portion 2 b needs only be formed in a columnar shape, and may for example be formed in a polygonal columnar shape.
  • the main plate 2 a is driven into rotation by the motor by use of the boss portion 2 b in between.
  • the fan 2 has the side plate 2 c , which is ring-shaped and is attached to ends of the plurality of blades 2 d that are opposite to the main plate 2 a in the axial direction of the rotation axis RA.
  • the side plate 2 c fixes the ends of the plurality of blades 2 d that are opposite to the main plate 2 a .
  • the side plate 2 c is provided at an outer circumferential face 2 f of the fan 2 , and in the fan 2 , is located such that the side plate 2 c faces the main plate 2 a .
  • the side plate 2 c is provided at outer portions of the blades 2 d in radial directions that start from the rotation axis RA as a radial center.
  • the side plate 2 c may be provided at distal end portions of the plurality of blades 2 d that project from the main plate 2 a in a direction of the rotation axis RA.
  • the side plate 2 c joins the plurality of blades 2 d with each other, thereby maintaining a positional relationship between the distal end of each blade 2 d and the distal end of the other blade 2 d and reinforcing the plurality of blades 2 d.
  • the side plate 2 c includes a first side plate 2 ca , which is ring-shaped and is located such that the first side plate 2 ca faces the main plate 2 a , and a second side plate 2 cb , which is ring-shaped and is located such that the second side plate 2 cb faces the main plate 2 a and is located opposite to the first side plate 2 ca across the main plate 2 a .
  • the term “side plate 2 c ” is a generic name for the first side plate 2 ca and the second side plate 2 cb
  • the fan 2 has the first side plate 2 ca at one side of the main plate 2 a in the axial direction of the rotation axis RA and has the second side plate 2 cb at the other side.
  • the first side plate 2 ca is located at the right side of the main plate 2 a and the second side plate 2 cb is located at the left side of the main plate 2 a , the first side plate 2 ca and the second side plate 2 cb may swap their positions with each other.
  • the plurality of blades 2 d are arranged in the circumferential direction CD centered around the rotation axis RA. One end of each of the plurality of blades 2 d is connected to the main plate 2 a , and the other end of each of the plurality of blades 2 d is connected to the side plate 2 c . Each of the plurality of blades 2 d is located at least between the main plate 2 a and the side plate 2 c .
  • the plurality of blades 2 d are arranged in a circumferential manner centered around the boss portion 2 b and have their proximal ends fixed on surfaces of the main plate 2 a.
  • the plurality of blades 2 d are provided on one surface of the main plate 2 a and the other surface of the main plate 2 a in the axial direction of the rotation axis RA.
  • the plurality of blades 2 d are provided on both sides of the main plate 2 a in the axial direction of the rotation axis RA.
  • the blades 2 d are placed at regular spacings from each other in the circumferential direction CD around the periphery 2 a 1 of the main plate 2 a .
  • the blades 2 d are provided such that the blades 2 d rise from the main plate 2 a and are each formed in the shape of a plate.
  • the blades 2 d are provided such that the blades 2 d rise substantially perpendicular to the main plate 2 a , this is not intended to impose any limitation.
  • the blades 2 d may be provided at an angle to a direction perpendicular to the main plate 2 a.
  • the fan 2 is driven into rotation around the rotation axis RA by driving of the motor (not illustrated).
  • the rotation of the fan 2 causes gas outside the centrifugal air-sending device 1 to be sucked into the space surrounded by the main plate 2 a and the plurality of blades 2 d through an air inlet 5 formed in the scroll casing 4 and the fan air inlet 2 e of the fan 2 , which are shown in FIG. 1 .
  • the rotation of the fan 2 causes air sucked into the space surrounded by the main plate 2 a and the plurality of blades 2 d to be sent out outward in radial directions of the fan 2 through a space between a blade 2 d and an adjacent blade 2 d.
  • the scroll casing 4 houses the fan 2 inside and rectifies a flow of air blown out from the fan 2 .
  • the scroll casing 4 is a double-suction casing having side walls 4 a at both respective sides of the main plate 2 a in the axial direction of the rotation axis RA with the after-mentioned air inlets 5 formed in the side walls 4 a .
  • the scroll casing 4 has a scroll portion 41 and a discharge portion 42 .
  • the scroll casing 4 has a peripheral wall 4 c , which is spiral-shaped, and at least one side wall 4 a , which has a bell mouth 3 , which forms an air inlet 5 , which communicates with a space surrounded by the main plate 2 a and the plurality of blades 2 d.
  • the scroll portion 41 has an air trunk through which a dynamic pressure of the airflow generated by the fan 2 is converted into a static pressure.
  • the scroll portion 41 has a side wall 4 a covering the fan 2 in the axial direction of the rotation axis RA and a peripheral wall 4 c surrounding the fan 2 in radial directions that start from the rotation axis RA, as a radial center, of the boss portion 2 b.
  • the scroll casing 4 has at least one side wall 4 a , which has a bell mouth 3 , which forms an air inlet 5 .
  • the at least one side wall 4 a of the scroll casing 4 includes two side walls 4 a . These side walls 4 a of Embodiment 1 are located at both respective sides of the fan 2 in the axial direction of the rotation axis RA. The two side walls 4 a located at both respective sides of the fan 2 are formed to face each other across the peripheral wall 4 c .
  • the scroll casing 4 of Embodiment 1 includes a first side wall 4 a 1 and a second side wall 4 a 2 as the side walls 4 a.
  • the first side wall 4 a 1 is a side wall 4 a that is located at a side that is opposite to the main plate 2 a and at which the first side plate 2 ca is located.
  • the second side wall 4 a 2 is a side wall 4 a that is located at a side that is opposite to the main plate 2 a and at which the second side plate 2 cb is located.
  • the term “side wall 4 a ” is a generic name for the first side wall 4 a 1 and the second side wall 4 a 2 .
  • the side wall 4 a of the scroll casing 4 has an air inlet 5 formed in the side wall 4 a such that that air can flow between the fan 2 and the outside of the scroll casing 4 .
  • the air inlet 5 is an air inlet that communicates with the fan air inlet 2 e and allows gas to flow into the space surrounded by the main plate 2 a and the plurality of blades 2 d.
  • the air inlet 5 provided in the side wall 4 a is formed by the bell mouth 3 .
  • the air inlet 5 formed by the bell mouth 3 allows a space outside the scroll casing 4 and the space surrounded by the main plate 2 a and the plurality of blades 2 d to communicate with each other.
  • the bell mouth 3 allows gas that is to be sucked into the fan 2 to be rectified and flow into the fan 2 through the fan air inlet 2 e.
  • the peripheral wall 4 c is a wall that guides the airflow generated by the fan 2 to the discharge port 42 a along a curved wall surface.
  • the peripheral wall 4 c is formed in a spiral shape.
  • the peripheral wall 4 c is formed such that the distance of the peripheral wall 4 c from the rotation axis RA gradually increases as the peripheral wall 4 c extends in the direction of rotation R of the fan 2 .
  • the peripheral wall 4 c is formed such that in the direction of rotation R of the fan 2 , a gap between the peripheral wall 4 c and the outer circumference of the fan 2 increases at a predetermined rate from the tongue portion 43 to the discharge portion 42 and the flow passage area of air gradually increases.
  • An example of the spiral shape of the peripheral wall 4 c is a shape such as a logarithmic spiral, a spiral of Archimedes, and an involute curve.
  • the inner circumferential surface of the peripheral wall 4 c forms a curved surface smoothly curved along a circumferential direction of the fan 2 from the tongue portion 43 , from which the peripheral wall 4 c extends to be formed in the spiral shape, to a winding-end portion 41 b until which the peripheral wall 4 c extends to be formed in the spiral shape.
  • Such a configuration allows air sent out from the fan 2 to smoothly flow through the gap between the fan 2 and the peripheral wall 4 c toward the discharge portion 42 in the direction of an arrow F 1 shown in FIG. 3 . This effects an efficient rise in static pressure of air from the tongue portion 43 toward the discharge portion 42 in the scroll casing 4 .
  • the peripheral wall 4 c is a wall provided between the side walls 4 a , which face each other, and forms a curved surface extending along the direction of rotation R of the fan 2 .
  • the peripheral wall 4 c is for example located parallel to the axial direction of the rotation axis RA and covers the fan 2 . It should be noted that the peripheral wall 4 c may be formed at an angle to an axial direction of the rotation axis RA of the fan 2 , and is not limited to being located parallel to the axial direction of the rotation axis RA.
  • the peripheral wall 4 c forms an inner wall surface that faces the outer circumferential face 2 f of the fan 2 .
  • the peripheral wall 4 c faces outer circumferential ends of the plurality of blades 2 d that form the outer circumferential face 2 f of the fan 2 .
  • the peripheral wall 4 c faces ends of the blades 2 d through which air is blown out from the fan 2 .
  • the peripheral wall 4 c is provided over an area from the tongue portion 43 , from which the peripheral wall 4 c extends to be formed in the spiral shape, to the winding-end portion 41 b , which is located at a boundary between the discharge portion 42 and the scroll portion 41 that are away from the tongue portion 43 , along the direction of rotation R of the fan 2 .
  • the tongue portion 43 is an end of the peripheral wall 4 c that forms a curved surface upstream in a direction of flow of gas allowed by rotation of the fan 2 to flow along the peripheral wall 4 c through an internal space of the scroll casing 4 .
  • the winding-end portion 41 b is an end of the peripheral wall 4 c that forms a curved surface downstream in the direction of flow of gas allowed by the rotation of the fan 2 to flow along the peripheral wall 4 c through the internal space of the scroll casing 4 .
  • the scroll casing 4 has a tongue portion 43 , which forms a curved surface at a winding-start portion of the peripheral wall 4 c that is closer to the rotation axis RA of the fan 2 than are other portions of the peripheral wall 4 c , and the tongue portion 43 guides the airflow generated by the fan 2 to the discharge port 42 a .
  • the peripheral wall 4 c includes the tongue portion 43 at an end of the peripheral wall 4 c that is closer to the discharge portion 42 than is the other end of the peripheral wall 4 c .
  • the tongue portion 43 is formed at the winding-start portion of the peripheral wall 4 c , which is spiral-shaped.
  • the tongue portion 43 is located at a boundary with a diffuser plate 42 c of the after-mentioned discharge portion 42 .
  • the tongue portion 43 is formed to have a curved surface and is formed in the shape of an arc when seen in the axial direction of the rotation axis RA.
  • the tongue portion 43 is formed with a predetermined radius of curvature, and the peripheral wall 4 c is smoothly connected to the diffuser plate 42 c with the tongue portion 43 in between.
  • the tongue portion 43 is in substantially the same shape in the axial direction of the rotation axis RA when seen from the discharge port 42 a and is shaped along the axial direction of the rotation axis RA.
  • the tongue portion 43 reduces inflow of air from the winding start to the winding end of a scroll flow passage.
  • the tongue portion 43 is located in an upstream part of a ventilation flue, and has a role to effect diversion into a flow of air in the direction of rotation R of the fan 2 and a flow of air in a discharge direction from a downstream part of the ventilation flue toward the discharge port 42 a . Further, a flow of air flowing into the discharge portion 42 rises in static pressure during passage through the scroll casing 4 to be high in pressure. Therefore, the tongue portion 43 has a function of separating such different pressures.
  • the scroll casing 4 has an extension plate 45 , which is plate-shaped, projects from the tongue portion 43 , is spaced apart from the fan 2 at a spacing SP, and extends from the tongue portion 43 along outer peripheries 2 g of the fan 2 .
  • the extension plate 45 is formed to project from the tongue portion 43 in a direction of reverse rotation of the fan 2 .
  • the direction of reverse rotation of the fan 2 is a direction opposite to the direction of rotation R of the fan 2 .
  • the extension plate 45 extends from the tongue portion 43 along the outer peripheries 2 g of the fan 2 in the circumferential direction CD and extends in the axial direction of the rotation axis RA.
  • the extension plate 45 has one portion that is closer to each of the side plates 2 c than is another portion of the extension plate 45 that is closer to the main plate 2 a than is the one portion, and the one portion is formed longer than the other portion in the circumferential direction CD (see FIG. 1 ) of the fan 2 .
  • the length of the extension plate 45 which projects from the tongue portion 43 , is longest in the one portion and shortest in the other portion.
  • the extension plate 45 has one portion that is closer to each of the side plates 2 c than is another portion of the extension plate 45 that is closer to the main plate 2 a than is the one portion in the axial direction of the rotation axis RA, and the one portion is formed longer than the other portion in the circumferential direction CD. It should be noted that the one portion closer to the corresponding side plate 2 c and the other portion closer to the main plate 2 a indicate a relative positional relationship between the position of the extension plate 45 and other positions in the axial direction of the rotation axis RA.
  • the scroll casing 4 has, in a case in which the scroll casing 4 is projected in an axial direction of the rotation axis RA, a tongue-portion-side end 42 c 1 located in a discharge-port edge 42 a 1 , which is a portion that corresponds to the discharge port 42 a , and the tongue-portion-side end 42 c 1 is an end that is closer to the tongue portion 43 than is the other end of the discharge-port edge 42 a 1 . Further, as shown in FIG.
  • the scroll casing 4 has, in a case in which the scroll casing 4 is projected in an axial direction of the rotation axis RA, a far end 42 c 2 located in a discharge-port edge 42 a 1 , which is a portion that corresponds to the discharge port 42 a , and the far end 42 c 2 is an end that is opposite to tongue-portion-side end 42 c 1 .
  • the tongue-portion-side end 42 c 1 is a first end
  • the far end 42 c 2 is a second end.
  • the tongue-portion-side end 42 c 1 is located opposite to an extreme distal end 46 a in the circumferential direction CD across a reference line RL drawn perpendicular to the discharge-port edge 42 a 1 from the rotation axis RA.
  • the extreme distal ends 46 a are respective portions of distal end portions 46 that extend in a direction of projection in which the extension plate 45 projects from the tongue portion 43 , and are each located at a boundary between a corresponding distal end portion 46 and the corresponding side wall 4 a.
  • the part of the fan 2 that is farthest away from the rotation axis RA in a radial direction of the fan 2 in a case in which the scroll casing 4 is looked into from the discharge port 42 a is an apex 2 h .
  • the extension plate 45 is formed such that the extreme distal ends 46 a are located between the tongue portion 43 and the apex 2 h in a case in which the scroll casing 4 is looked into from the discharge port 42 a.
  • the extension plate 45 includes a basal portion 47 , which serves as a boundary between the extension plate 45 and the tongue portion 43 .
  • the extension plate 45 is formed such that the thickness of a plate that forms the extension plate 45 from the basal portion 47 , which serves as a boundary between the extension plate 45 and the tongue portion 43 , to the extreme distal ends 46 a is a uniform thickness that falls within a predetermined range.
  • the extension plate 45 is formed such that the thickness of a plate that forms the extension plate 45 is equal to the thickness of a plate that forms the peripheral wall 4 c .
  • the thickness of the extension plate 45 is less than or equal to 2 mm in a case in which the extension plate 45 is made from a steel plate and less than or equal to 4 mm in a case in which the extension plate 45 is made from resin, the thickness of the extension plate 45 is not limited to these thicknesses.
  • the extension plate 45 of Embodiment 1 includes a first plate portion 45 a and a second plate portion 45 b , which are formed in right triangular shapes when seen from the discharge port 42 a .
  • the extension plate 45 is formed such that an oblique side of the first plate portion 45 a and an oblique side of the second plate portion 45 b face each other in the axial direction of the rotation axis RA.
  • the extension plate 45 has a notch 46 b cut in a V shape when seen from the discharge port 42 a . Air of which pressure is raised in the scroll casing 4 and that flows toward the discharge port 42 a passes through the notch 46 b and is discharged out from the scroll casing 4 through the discharge port 42 a .
  • the distal end portions 46 of the extension plate 45 each form an edge 46 c of the extension plate 45 , and the edges 46 c of the extension plate 45 form the V-shaped notch 46 b .
  • the edges 46 c of the extension plate 45 are formed in a V shape. As with the edges 46 c shown in FIG. 2 , an edge portion of the extension plate 45 that is formed by each of the distal end portions 46 is formed in a linear shape between the one portion closer to the corresponding side plate 2 c and the other portion closer to the main plate 2 a.
  • the extension plate 45 has a shortest portion 48 , which is a portion of the extension plate 45 that is shortest in length in the direction of projection, in which the extension plate 45 projects from the tongue portion 43 , when seen from the discharge port 42 a , and the shortest portion 48 corresponds in position to the main plate 2 a in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 is formed such that as shown in FIG. 2 , in a case in which the centrifugal air-sending device 1 is looked into from the discharge port 42 a , a portion of the centrifugal air-sending device 1 in which the main plate 2 a is located in the axial direction of the rotation axis RA is largest in the width of an opening perpendicular to the rotation axis RA.
  • the discharge portion 42 forms the discharge port 42 a through which airflow that is generated by the fan 2 and passes through the scroll portion 41 is discharged.
  • the discharge portion 42 is formed by a hollow pipe having a rectangular cross-section orthogonal to a flow direction of air flowing along the peripheral wall 4 c . It should be noted that the cross-sectional shape of the discharge portion 42 is not limited to a rectangle.
  • the discharge portion 42 forms a flow passage through which air that is sent out from the fan 2 and flows through a gap between the peripheral wall 4 c and the fan 2 is guided to be exhausted out from the scroll casing 4 .
  • one end of the discharge portion 42 is fixed to the scroll casing 4 and forms an inlet 42 g through which air flows from the scroll casing 4 into the discharge portion 42 . Further, another end of the discharge portion 42 forms the discharge port 42 a , through which air having flowed through the flow passage in the discharge portion 42 is discharged into the outside air.
  • the discharge portion 42 has an extended plate 42 b , a diffuser plate 42 c , a first side plate portion 42 d , and a second side plate portion 42 e .
  • the extended plate 42 b is formed integrally with the peripheral wall 4 c to smoothly continue into the winding-end portion 41 b downstream of the peripheral wall 4 c .
  • the diffuser plate 42 c is formed integrally with the tongue portion 43 of the scroll casing 4 and faces the extended plate 42 b .
  • the diffuser plate 42 c is for example formed at a predetermined angle to the extended plate 42 b such that the cross-sectional area of the flow passage gradually increases along a direction of flow of air in the discharge portion 42 .
  • the diffuser plate 42 c is not limited to this configuration.
  • the first side plate portion 42 d is formed integrally with the first side wall 4 a 1 of the scroll casing 4
  • the second side plate portion 42 e is formed integrally with the second side wall 4 a 2 of the scroll casing 4 , which is opposite to the first side wall 4 a 1
  • the first side plate portion 42 d and the second side plate portion 42 e are formed between the extended plate 42 b and the diffuser plate 42 c .
  • the discharge portion 42 has a rectangular cross-section flow passage defined by the extended plate 42 b , the diffuser plate 42 c , the first side plate portion 42 d , and the second side plate portion 42 e.
  • a flow passage (arrow F 2 ) of airflow that flows toward the discharge port 42 a and a flow passage (arrow F 3 ) of airflow that flows again upstream from the tongue portion 43 are formed.
  • the tongue portion 43 has the function of separating different pressures and, by use of the curved surface, includes a function of guiding, to each flow passage, air that flows into the discharge portion 42 .
  • FIG. 4 is a side view of a first modification of the centrifugal air-sending device 1 of Embodiment 1 as seen from the discharge port 42 a .
  • the extension plate 45 has a notch 46 b 1 cut in a U shape when seen from the discharge port 42 a . Air of which pressure is raised in the scroll casing 4 and that flows toward the discharge port 42 a passes through the notch 46 b 1 and is discharged out from the scroll casing 4 through the discharge port 42 a .
  • the distal end portions 46 of the extension plate 45 each form an edge 46 c of the extension plate 45 , and the edges 46 c of the extension plate 45 form the U-shaped notch 46 b 1 .
  • the edges 46 c of the extension plate 45 are formed in a U shape.
  • FIG. 5 is a side view of a second modification of the centrifugal air-sending device 1 of Embodiment 1 as seen from the discharge port 42 a .
  • the extension plate 45 has a notch 46 b 2 cut in a substantially V shape as a whole when seen from the discharge port 42 a . Air of which pressure is raised in the scroll casing 4 and that flows toward the discharge port 42 a passes through the notch 46 b 2 and is discharged out from the scroll casing 4 through the discharge port 42 a.
  • the distal end portions 46 of the extension plate 45 each form an edge 46 c of the extension plate 45 , and the edges 46 c of the extension plate 45 form the V-shaped notch 46 b 2 .
  • the edges 46 c of the extension plate 45 are formed in a substantially V shape as a whole. Further, the edges 46 c each form an edge portion formed in not a linear shape but a wave shape when seen from the discharge port 42 a . As with the edges 46 c shown in FIG. 5 , edge portions of the extension plate 45 that form the notch 46 b 2 are each formed in a wave shape between the one portion closer to the corresponding side plate 2 c and the other portion closer to the main plate 2 a.
  • the centrifugal air-sending device 1 is formed such that when the motor (not illustrated) is driven, the main plate 2 a , to which a motor shaft is connected, rotates and the plurality of blades 2 d rotate around the rotation axis RA by use of the main plate 2 a in between. Rotation of the fan 2 causes air outside the scroll casing 4 to be sucked into the scroll casing 4 through the air inlets 5 .
  • the air sucked into the scroll casing 4 is guided by the bell mouths 3 and sucked into the fan 2 .
  • the air sucked into the fan 2 turns into airflow to which dynamic pressure and static pressure are applied, and the airflow is blown out outward in radial directions of the fan 2 .
  • the airflow blown out from the fan 2 is caused by the pressure-raising action of the fan 2 to be blown out from the fan 2 into the scroll casing 4 .
  • the airflow flowing through the inside of the scroll casing 4 has its pressure raised by flowing through an air trunk that is gradually expanded from a winding-start portion to a winding-end portion by the spiral-shaped peripheral wall 4 c .
  • the air blown out from the fan 2 into the scroll casing 4 recovers its static pressure by having its speed reduced through an expanded air trunk defined by the peripheral wall 4 c of the scroll casing 4 , and is blown out from the scroll casing 4 through the discharge port 42 a shown in FIG. 1 .
  • the centrifugal air-sending device 1 has the extension plate 45 , which is plate-shaped, projects from the tongue portion 43 , is spaced apart from the fan 2 , and extends from the tongue portion 43 along outer peripheries 2 g of the fan 2 .
  • the extension plate 45 has one portion that is closer to each of the side plates 2 c than is another portion of the extension plate 45 that is closer to the main plate 2 a than is the one portion.
  • the one portion of the extension plate 45 is formed longer than the other portion in the circumferential direction CD of the fan 2 .
  • the one portion of the extension plate 45 reduces backflow of the airflow from around the discharge port 42 a toward the inside of the scroll casing 4 , whereby the airflow can be smoothly guided from the one portion closer to the corresponding side plate 2 c to the discharge port 42 a .
  • the variation in length between the other portion closer to the main plate 2 a and the one portion closer to the corresponding side plate 2 c makes it possible to, without reducing the flow of air in the other portion, on which the volume of air concentrates, reduce backflow of airflow generated in the one portion, making it possible to control a reduction in the volume of air.
  • the centrifugal air-sending device 1 allows the airflow flowing through the inside of the scroll casing 4 to be discharged through the discharge port 42 a along with a wind speed distribution of the airflow.
  • the formation of the extension plate 45 in the shape of a plate makes it possible to ensure the distance between the extension plate 45 and the discharge port 42 a and sufficiently ensure an air trunk, thus making it possible to surely raise pressure inside the scroll casing 4 .
  • the extension plate 45 has a distal end portion 46 , which extends in a direction of projection in which the extension plate 45 projects from the tongue portion 43 .
  • the distal end portion 46 has an extreme distal end 46 a located at a boundary between the distal end portion 46 and the at least one side wall 4 a .
  • the tongue-portion-side end 42 c 1 is located opposite to the extreme distal end 46 a in the circumferential direction CD across the reference line RL. Therefore, the centrifugal air-sending device 1 can ensure the opening area of the discharge port 42 a and control a reduction in the volume of air that is discharged.
  • FIG. 6 is a schematic view of a centrifugal air-sending device 111 according to a comparative example as seen in an axial direction of a rotation axis RA. It should be noted that FIG. 6 is also a conceptual diagram in which a scroll casing 114 of the centrifugal air-sending device 111 of the comparative example is projected in the axial direction of the rotation axis RA.
  • FIG. 7 is a side view of the centrifugal air-sending device 111 in FIG. 6 as seen from a discharge port 142 a .
  • the centrifugal air-sending device 111 of the comparative example shown in FIGS. 6 and 7 is the one obtained by assigning reference signs to the centrifugal air-sending device of Patent Literature 1.
  • the centrifugal air-sending device 111 which is installed in a narrow space, cannot keep sufficient distance between the rotation axis RA and the discharge port 142 a . Therefore, the centrifugal air-sending device 111 cannot lengthen the length of a discharge portion 142 .
  • the centrifugal air-sending device 111 has a fan 112 and a scroll casing 114 .
  • the scroll casing 114 has a peripheral wall 114 c and a tongue portion 143 .
  • the scroll casing 4 has, in a case in which the scroll casing 114 is projected in an axial direction of the rotation axis RA, a tongue-portion-side end 142 c 1 and a far end 142 c 2 , which are located in a discharge-port edge 142 a 1 , which is a portion that corresponds to the discharge port 142 a.
  • the tongue portion 143 of the centrifugal air-sending device 111 is formed such that the thickness of a wall of the tongue portion 143 is greater than the thickness of the peripheral wall 114 c when seen in the axial direction of the rotation axis RA.
  • an increase in the thickness of the wall of the tongue portion 143 leads to a reduction in the distance between the tongue-portion-side end 142 c 1 and the far end 142 c 2 and leads to a reduction in the opening area of the discharge port 142 a .
  • an increase in the thickness of the wall of the tongue portion 143 makes an end of the tongue portion 143 in the discharge port 142 a complex in shape as shown in FIG. 7 .
  • the centrifugal air-sending device 111 of the comparative example is formed such that as shown in FIG. 6 , the centrifugal air-sending device 1 does not have a reference line RL drawn perpendicular to the discharge-port edge 42 a 1 from the rotation axis RA, and is shorter in distance between the tongue-portion-side end 142 c 1 and the far end 142 c 2 than the centrifugal air-sending device 1 of Embodiment 1. Therefore, the centrifugal air-sending device 111 according to the comparative example is smaller in opening area of the discharge port 142 a than the centrifugal air-sending device 1 of Embodiment 1.
  • the centrifugal air-sending device 111 may not be able to bring about an effect of raising pressure inside the scroll casing 4 , as the air trunk cannot be sufficiently expanded, and may reduce the volume of air that is discharged, as the discharge port 142 a has a narrow opening.
  • the centrifugal air-sending device 1 of Embodiment 1 has the extension plate 45 thus formed and the tongue-portion-side end 42 c 1 . Therefore, in the centrifugal air-sending device 1 , the extension plate 45 reduces backflow of airflow from around the discharge port 42 a toward the inside of the scroll casing 4 , and the formation of the extension plate 45 in the shape of a plate makes it possible to ensure a rise in pressure inside the scroll casing 4 . Further, in the centrifugal air-sending device 1 , the tongue-portion-side end 42 c 1 is located opposite to the extreme distal ends 46 a in the circumferential direction CD across the reference line RL.
  • the centrifugal air-sending device 1 of Embodiment 1 makes it possible to, even in a case in which the centrifugal air-sending device 1 is installed in a narrow space and cannot keep sufficient distance between the rotation axis RA and the discharge port 142 a , bring about the aforementioned effects by having the extension plate 45 and the tongue-portion-side end 42 c 1 .
  • the extension plate 45 is formed such that the thickness of a plate that forms the extension plate 45 from the basal portion 47 , which serves as a boundary between the extension plate 45 and the tongue portion 43 , to the extreme distal ends 46 a is a uniform thickness that falls within a predetermined range. Therefore, the centrifugal air-sending device 1 makes it possible to ensure the distance between the extension plate 45 and the discharge port 42 a and sufficiently ensure an air trunk, thus making it possible to ensure a rise in pressure inside the scroll casing 4 . Further, in the centrifugal air-sending device 1 , the extension plate 45 is not complex in shape. This makes it easy to manufacture the scroll casing 4 and makes it possible to reduce manufacturing cost.
  • the extension plate 45 is formed such that the thickness of a plate that forms the extension plate 45 is equal to the thickness of a plate that forms the peripheral wall 4 c . Therefore, the centrifugal air-sending device 1 does not narrow an air trunk connected to the discharge port 142 a unlike in the case of the tongue portion 143 of the centrifugal air-sending device 1 of the comparative example and makes it possible to ensure the distance between the extension plate 45 and the discharge port 42 a and sufficiently ensure an air trunk, thus making it possible to ensure a rise in pressure inside the scroll casing 4 . Further, in the centrifugal air-sending device 1 , the extension plate 45 and the peripheral wall 4 c are formed by plates of the same thickness, and the scroll casing 4 is not complex in shape. This makes it easy to manufacture the scroll casing 4 and makes it possible to reduce manufacturing cost.
  • the extension plate 45 includes the first plate portion 45 a and the second plate portion 45 b , which are formed in right triangular shapes when seen from the discharge port 42 a , and is formed such that an oblique side of the first plate portion 45 a and an oblique side of the second plate portion 45 b face each other.
  • a centrifugal air-sending device is not provided with the extension plate 45 , a backflow region of airflow increases from the other portion closer to the main plate 2 a toward the one portion closer to the corresponding side plate 2 c in the scroll casing 4 .
  • a centrifugal air-sending device is formed such that the amount of airflow from the inside of the scroll casing toward the discharge port is large in a portion that forms the main plate 2 a.
  • the centrifugal air-sending device 1 ensures an opening area in a portion of the main plate 2 a in which the amount of airflow from the inside of the scroll casing 4 toward the discharge port 42 a is large, and is formed such that the amount of airflow that is discharged does not decrease. Further, in the centrifugal air-sending device 1 , by having the first plate portion 45 a and the second plate portion 45 b , portions of an opening in the vicinity of the side plates 2 c in which the backflow amount of airflow is large in a case in which the extension plate 45 is not provided are covered by the extension plate 45 . This makes it possible to reduce backflow of the airflow.
  • the variation in length between the other portion closer to the main plate 2 a and the one portion closer to the corresponding side plate 2 c makes it possible to, without reducing the flow of air in the other portion closer to the main plate 2 a , on which the volume of air concentrates, reduce backflow of airflow generated in the one portion closer to the corresponding side plate 2 c , making it possible to control a reduction in the volume of air.
  • the extension plate 45 has a notch 46 b cut in a V shape when seen from the discharge port 42 a . Further, by having the notch 46 b , the centrifugal air-sending device 1 ensures an opening area in the other portion closer to the main plate 2 a and is formed such that the amount of airflow that is discharged does not decrease. Further, in the centrifugal air-sending device 1 , the portions of the opening in the vicinity of the side plates 2 c are covered by the extension plate 45 . This makes it possible to reduce backflow of the airflow.
  • the variation in length between the other portion closer to the main plate 2 a and the one portion closer to the corresponding side plate 2 c makes it possible to, without reducing the flow of air in the other portion closer to the main plate 2 a , on which the volume of air concentrates, reduce backflow of airflow generated in the one portion closer to the corresponding side plate 2 c , making it possible to control a reduction in the volume of air.
  • the extension plate 45 has a notch 46 b cut in a U shape when seen from the discharge port 42 a . Further, by having the notch 46 b , the centrifugal air-sending device 1 ensures an opening area in the other portion closer to the main plate 2 a and is formed such that the amount of airflow that is discharged does not decrease. Further, in the centrifugal air-sending device 1 , the portions of the opening in the vicinity of the side plates 2 c are covered by the extension plate 45 . This makes it possible to reduce backflow of the airflow.
  • the variation in length between the other portion closer to the main plate 2 a and the one portion closer to the corresponding side plate 2 c makes it possible to, without reducing the flow of air in the other portion closer to the main plate 2 a , on which the volume of air concentrates, reduce backflow of airflow generated in the one portion closer to the corresponding side plate 2 c , making it possible to control a reduction in the volume of air.
  • the extension plate 45 has an edge portion that forms the notch 46 b and is formed in a wave shape from the other portion closer to the main plate 2 a to the one portion closer to the corresponding side plate 2 c .
  • forming an end of the extension plate 45 in a wave shape makes it possible to shift a phase of pressure fluctuation that is caused when the blades 2 d pass near the end of the extension plate 45 , making it possible to reduce noise attributed to the passage of the blades 2 d.
  • FIG. 8 is a schematic view of a centrifugal air-sending device 1 according to Embodiment 2 as seen in an axial direction of the rotation axis RA at a position in the centrifugal air-sending device 1 indicated by line A-A in FIG. 2 .
  • FIG. 8 is also a conceptual diagram in which a scroll casing 4 of the centrifugal air-sending device 1 of Embodiment 2 is projected in the axial direction of the rotation axis RA.
  • components that are identical in configuration to those of the centrifugal air-sending device 1 in FIGS. 1 to 5 are given identical reference signs, and a description of such components is omitted.
  • the centrifugal air-sending device 1 according to Embodiment 2 is intended to further specify the configuration of the plurality of blades 2 d .
  • the configuration of components other than the plurality of blades 2 d is similar to that of the centrifugal air-sending device 1 according to Embodiment 1. The following thus gives a description with reference to FIG. 8 with a focus on the configuration of the plurality of blades 2 d of the centrifugal air-sending device 1 according to Embodiment 2.
  • Each of the plurality of blades 2 d has a turbo blade portion 12 including an inner circumferential end 14 located closer to the rotation axis RA than is an outer circumferential end 15 in a radial direction that starts from the rotation axis RA as a radial center, and the turbo blade portion 12 forms a backward-curved blade.
  • each of the plurality of blades 2 d has a sirocco blade portion 13 including the outer circumferential end 15 located closer to an outer circumference of the blade 2 d than is the inner circumferential end 14 in the radial direction that starts from the rotation axis RA as a radial center, and the sirocco blade portion 13 forms a forward-curved blade.
  • each of the blades 2 d is formed such that the turbo blade portion 12 and the sirocco blade portion 13 are arranged in this order from the rotation axis RA toward the outer circumference in a radial direction of the fan 2 .
  • the turbo blade portion 12 and the sirocco blade portion 13 are integrally formed.
  • the turbo blade portion 12 forms a leading edge of the blade 2 d
  • the sirocco blade portion 13 forms a trailing edge of the blade 2 d .
  • 2 d is formed such that in a radial direction of the fan 2 , a region of the blade 2 d in which the turbo blade portion 12 is formed is larger than a region of the blade 2 d in which the sirocco blade portion 13 is formed.
  • the inter-blade gap between a plurality of blades 2 d widens from the leading edges toward the trailing edges as shown in FIG. 8 .
  • the fan 2 is formed such that the inter-blade gap between turbo blade portions 12 widens from the inner circumference toward the outer circumference.
  • the fan 2 is formed such that the inter-blade gap between sirocco blade portions 13 is wider than the inter-blade gap between turbo blade portions 12 and widens from the inner circumference toward the outer circumference.
  • Each of the plurality of blades 2 d has the turbo blade portion 12 including the inner circumferential end 14 and forming a backward-curved blade and the sirocco blade portion 13 including the outer circumferential end 15 and forming a forward-curved blade.
  • the centrifugal air-sending device 1 can raise pressure in an inter-blade gap by having the turbo blade portion 12 on the inner circumference of the fan 2 and having the sirocco blade portion 13 on the outer circumference of the fan 2 .
  • centrifugal air-sending device 1 can raise pressure in an inter-blade gap by having the turbo blade portion 12 on the inner circumference of the fan 2 and having the sirocco blade portion 13 on the outer circumference of the fan 2 , airflow tends to flow backward from around the discharge port 42 a to the inside of the scroll casing 4 , as the volume of air that flows out through the inter-blade gap is small.
  • the centrifugal air-sending device 1 is formed such that the one portion of the extension plate 45 closer to the corresponding side plate 2 c reduces backflow of the airflow from around the discharge port 42 a toward the inside of the scroll casing 4 , whereby the airflow can be smoothly guided from the one portion closer to the corresponding side plate 2 c to the discharge port 42 a .
  • the centrifugal air-sending device 1 allows the extension plate 45 to more remarkably bring about an airflow backflow prevention effect than in a case in which the fan 2 does not have the turbo blade portion 12 and the sirocco blade portion 13 .
  • FIG. 9 is a side view of a centrifugal air-sending device 1 according to Embodiment 3 as seen from a discharge port 42 a .
  • FIG. 10 is a conceptual diagram of an example of use of the centrifugal air-sending device 1 according to Embodiment 3. Further, components that are identical in configuration to those of the centrifugal air-sending devices 1 in FIGS. 1 to 8 are given identical reference signs, and a description of such components is omitted.
  • the centrifugal air-sending device 1 according to Embodiment 3 is intended to further specify the configuration of the fan 2 and the extension plate 45 .
  • the configuration of components other than the fan 2 and the extension plate 45 is similar to that of the centrifugal air-sending device 1 according to Embodiment 1 or 2. The following thus gives a description with reference to FIG. 9 with a focus on the configuration of the fan 2 and the extension plate 45 of the centrifugal air-sending device 1 according to Embodiment 3.
  • the plurality of blades 2 d of the fan 2 are provided on one surface of the main plate 2 a and the other surface of the main plate 2 a in the axial direction of the rotation axis RA.
  • a plurality of first blades 2 d 1 provided on the one surface of the main plate 2 a and a plurality of second blades 2 d 2 provided on the other surface of the main plate 2 a project from the main plate 2 a by different lengths.
  • the main plate 2 a of the fan 2 is formed such that the main plate 2 a is shifted to one side from a center position M of the fan 2 in the axial direction of the rotation axis RA.
  • the fan 2 is formed such that the length L 1 of each of the plurality of first blades 2 d 1 is greater than the length L 2 of each of the plurality of second blades 2 d 2 .
  • the main plate 2 a of the fan 2 is located such that the main plate 2 a is shifted to the second side plate 2 cb from the center position M to be closer to the second side plate 2 cb than to the first side plate 2 ca.
  • the extension plate 45 has the shortest portion 48 , which is a portion of the extension plate 45 that is shortest in length in the direction of projection, in which the extension plate 45 projects from the tongue portion 43 , when seen from the discharge port 42 a , and the shortest portion 48 corresponds in position to the main plate 2 a in the axial direction of the rotation axis RA.
  • the shortest portion 48 of the extension plate 45 is formed such that the shortest portion 48 is shifted to one side from the center position M of the fan 2 in the axial direction of the rotation axis RA.
  • the extension plate 45 is formed such that in the axial direction of the rotation axis RA, the maximum width W 1 of the first plate portion 45 a is greater than the maximum width W 2 of the maximum width W 2 of the second plate portion 45 b .
  • the maximum width W 1 of the first plate portion 45 a is the width of a section of the extension plate 45 between the first side plate 4 a 1 and the shortest portion 48 in the basal portion 47
  • the maximum width W 2 of the second plate portion 45 b is the width of a section of the extension plate 45 between the second side plate 4 a 2 and the shortest portion 48 in the basal portion 47 .
  • the first plate portion 45 a covers the plurality of first blades 2 d 1 in radial directions of the fan 2
  • the second plate portion 45 b covers the plurality of second blades 2 d 2 in radial directions of the fan 2 .
  • the centrifugal air-sending device 1 is formed such that as shown in FIG. 9 , in a case in which the centrifugal air-sending device 1 is looked into from the discharge port 42 a , a portion of the centrifugal air-sending device 1 in which the main plate 2 a is located in the axial direction of the rotation axis RA is largest in the width of an opening perpendicular to the rotation axis RA.
  • the portion of the centrifugal air-sending device 1 that is largest in the width of the opening perpendicular to the rotation axis RA is formed such that the largest portion is shifted from the center position M of the fan 2 in the axial direction of the rotation axis RA.
  • a wall surface portion 60 shown in FIG. 10 is a wall surface of an after-mentioned case 16 of the air-conditioning apparatus 10 or a wall surface of any type of device such as an air-sending device into which the centrifugal air-sending device 1 is incorporated.
  • the wall surface portion 60 and a motor 9 are resistance bodies against airflow that flows into the centrifugal air-sending device 1 .
  • the motor 9 is a resistance body that is located in a position that faces the wall surface portion 60 across the centrifugal air-sending device 1 and that prevents the flow of air.
  • the motor 9 is connected to the main plate 2 a by use of a motor shaft 9 a in between.
  • the centrifugal air-sending device 1 is formed such that in the axial direction of the rotation axis RA, the main plate 2 a is located such that the main plate 2 a is shifted from the center position M of the fan 2 to a side at which the distance between the scroll casing 4 and a resistance body positioned to face one side wall 4 a is shorter than the distance between the scroll casing 4 and another resistance body positioned to face the other side wall 4 a .
  • the centrifugal air-sending device 1 is formed such that in the axial direction of the rotation axis RA, the shortest portion 48 is located such that the shortest portion 48 is shifted from the center position M of the fan 2 to a side at which the distance between the scroll casing 4 and a resistance body positioned to face one side wall 4 a is shorter than the distance between the scroll casing 4 and another resistance body positioned to face the other side wall 4 a.
  • WL 1 is the distance between the motor 9 and the other side wall 4 a .
  • WL 2 is the distance between the one side wall 4 a of the scroll casing 4 and the wall surface portion 60 .
  • the centrifugal air-sending device 1 is located such that the main plate 2 a and the shortest portion 48 are shifted from the center position M of the fan 2 to the shorter one of the distances WL 1 and WL 2 .
  • the centrifugal air-sending device 1 is formed such that the main plate 2 a and the shortest portion 48 are located closer to the second side wall 4 a 2 than is the center position M of the fan 2 .
  • the centrifugal air-sending device 1 is formed such that the main plate 2 a and the shortest portion 48 are located closer to the first side wall 4 a 1 than is the center position M of the fan 2 .
  • the centrifugal air-sending device 1 when the distance between the scroll casing 4 and a resistance body positioned to face a side wall 4 a is long, the volume of sucked air that flows in through the air inlet 5 is large.
  • the centrifugal air-sending device 1 makes it possible to achieve a rise in pressure by increasing the total area of blades 2 d in which the volume of sucked air is large, making it possible to increase the volume of discharged air.
  • the centrifugal air-sending device 1 when the distance between the scroll casing 4 and a resistance body positioned to face a side wall 4 a is long, the volume of discharged air increases and the effect of airflow generated by airflow in the vicinity of the corresponding side plate 2 c flowing backward from around the discharge port 42 a to the inside of the scroll casing 4 is great.
  • the centrifugal air-sending device 1 makes it possible to secure a great width of a portion of the extension plate 45 at which the volume of sucked air is large in the axial direction of the rotation axis RA, making it possible to reduce backflow of the airflow in the vicinity of the corresponding side plate 2 c.
  • the extension plate 45 has the shortest portion 48 , which is a portion of the extension plate 45 that is shortest in length in the direction of projection when seen from the discharge port 42 a , and the shortest portion 48 corresponds in position to the main plate 2 a in the axial direction of the rotation axis RA. Further, the main plate 2 a is formed such that the main plate 2 a is shifted to one side from the center position M of the fan 2 in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 can bring about effects that are similar to those of Embodiments 1 and 2 or other embodiments by having the main plate 2 a and the shortest portion 48 located such that the main plate 2 a and the shortest portion 48 are shifted from the center position M to a side at which the volume of sucked air is small.
  • the centrifugal air-sending device 1 makes it possible to achieve a rise in pressure by increasing the total area of blades 2 d in which the volume of sucked air is large, making it possible to increase the volume of discharged air.
  • the centrifugal air-sending device 1 has the fan 2 with the shortest portion 48 shifted to a side at which the distance between one side wall 4 a and an airflow resistance body is shorter in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 makes it possible to secure a great width of a portion of the extension plate 45 at which the volume of sucked air is large in the axial direction of the rotation axis RA, making it possible to reduce backflow of the airflow in the vicinity of the corresponding side plate 2 c.
  • the shortest portion 48 of the extension plate 45 corresponds in position to the main plate 2 a in the axial direction of the rotation axis RA.
  • the variation in length between the other portion closer to the main plate 2 a and the one portion closer to the corresponding side plate 2 c makes it possible to, without reducing the flow of air in the other portion closer to the main plate 2 a , on which the volume of air concentrates, reduce backflow of airflow generated in the one portion closer to the corresponding side plate 2 c , making it possible to control a reduction in the volume of air.
  • FIG. 11 is a side view of a centrifugal air-sending device 1 according to Embodiment 4 as seen from a discharge port 42 a .
  • components that are identical in configuration to those of the centrifugal air-sending devices 1 in FIGS. 1 to 10 are given identical reference signs and a description of such components is omitted.
  • the centrifugal air-sending device 1 described in any one of Embodiments 1 to 3 is of a double-suction type, the centrifugal air-sending device 1 is not limited to a double-suction centrifugal air-sending device 1 but may be a single-suction centrifugal air-sending device 1 .
  • the centrifugal air-sending device 1 needs only have at least one side wall 4 a in which an air inlet 5 is formed.
  • the scroll casing 4 of the centrifugal air-sending device 1 has a side wall 4 a covering the fan 2 in the axial direction of the rotation axis RA of the fan 2 and having the air inlet 5 formed in the side wall 4 a and through which air is taken in and a peripheral wall 4 c surrounding the fan 2 in radial directions that start from the rotation axis RA as a radial center.
  • the scroll casing 4 of the single-suction centrifugal air-sending device 1 has a side wall 4 a 3 perpendicular to the axial direction of the rotation axis RA.
  • the scroll casing 4 of Embodiment 4 is a single-suction casing in which the air inlet 5 is formed only at one side of the fan 2 in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 of Embodiment 4 includes one side wall 4 a in which the air inlet 5 is formed and includes one side wall 4 a in which no air inlet 5 is formed.
  • the plurality of blades 2 d of the centrifugal air-sending device 1 are provided on one side of the main plate 2 a in the axial direction of the rotation axis RA.
  • the main plate 2 a of the fan 2 is located closer to the side wall 4 a 3 than is the side plate 2 c
  • the side plate 2 c of the fan 2 is located closer to the first side wall 4 a 1 than is the main plate 2 a.
  • the extension plate 45 of Embodiment 4 is formed in a right triangular shape when seen from the discharge port 42 a .
  • the extension plate 45 has a notch 46 b cut diagonally when seen from the discharge port 42 a .
  • the distal end portion 46 of the extension plate 45 forms an edge 46 c of the extension plate 45
  • the edge 46 c of the extension plate 45 forms the diagonal notch 46 b .
  • the edge 46 c of the extension plate 45 is formed in a diagonal shape.
  • an edge portion of the extension plate 45 that is formed by the distal end portion 46 may be formed in a linear shape between the one portion closer to the side plate 2 c and the other portion closer to the main plate 2 a .
  • an edge portion of the extension plate 45 that is formed by the distal end portion 46 may be formed in a wave shape between the one portion closer to the side plate 2 c and the other portion closer to the main plate 2 a.
  • the length of the extension plate 45 which projects from the tongue portion 43 , is longest in one portion closest to the side plate 2 c and shortest in another portion closest to the main plate 2 a .
  • the length of the extension plate 45 which projects from the tongue portion 43 , is longest in one portion of the extension plate 45 that is closest to the first side wall 4 a 1 , in which the air inlet 5 is formed, and shortest in another portion of the extension plate 45 that is closest to the side wall 4 a 3 , in which no air inlet 5 is formed.
  • the extension plate 45 has the shortest portion 48 , which is a portion of the extension plate 45 that is shortest in length in the direction of projection, in which the extension plate 45 projects from the tongue portion 43 , when seen from the discharge port 42 a , and the shortest portion 48 corresponds in position to the main plate 2 a in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 is formed such that as shown in FIG. 11 , in a case in which the centrifugal air-sending device 1 is looked into from the discharge port 42 a , a portion of the centrifugal air-sending device 1 in which the main plate 2 a is located in the axial direction of the rotation axis RA is largest in the width of an opening perpendicular to the rotation axis RA.
  • the scroll casing 4 of Embodiment 4 is a single-suction casing in which the air inlet 5 is formed only at one side of the fan 2 in the axial direction of the rotation axis RA.
  • the centrifugal air-sending device 1 of Embodiment 4 is a single-suction centrifugal air-sending device 1 having one side wall 4 a in which the air inlet 5 is formed and having one-sided configuration in which air is sucked into the scroll casing 4 .
  • the single-suction centrifugal air-sending device 1 too has the tongue-portion-side end 42 c 1 and the extension plate 45 of which length of extension from the tongue portion 43 increases from the other portion closer to the main plate 2 a toward the one portion closer to the side plate 2 c.
  • the extension plate 45 reduces backflow of airflow from around the discharge port 42 a toward the inside of the scroll casing 4 , and the formation of the extension plate 45 in the shape of a plate makes it possible to ensure a rise in pressure inside the scroll casing 4 .
  • the tongue-portion-side end 42 c 1 is located opposite to the extreme distal end 46 a in the circumferential direction CD across the reference line RL. This makes it possible to ensure the opening area of the discharge port 42 a and control a reduction in the volume of air that is discharged.
  • the single-suction centrifugal air-sending device 1 too makes it possible to bring about effects that are similar to those of the centrifugal air-sending device 1 any one of Embodiments 1 to 3 by having the tongue-portion-side end 42 c 1 and the extension plate 45 .
  • FIG. 12 is a perspective view of an air-conditioning apparatus 10 according to Embodiment 5.
  • FIG. 13 is a schematic view showing an internal configuration of the air-conditioning apparatus 10 according to Embodiment 5.
  • a centrifugal air-sending device 1 which is used in the air-conditioning apparatus 10 according to Embodiment 5
  • components that are identical in configuration to those of the centrifugal air-sending device 1 or other devices in FIGS. 1 to 11 are given identical reference signs, and a description of such components is omitted.
  • FIG. 13 omits an upper surface portion 16 a to show the internal configuration of the air-conditioning apparatus 10 .
  • the air-conditioning apparatus 10 includes the centrifugal air-sending devices 1 and a heat exchanger 20 through which air caused by the centrifugal air-sending devices 1 to flow passes. It should be noted that the air-conditioning apparatus 10 may include multiple centrifugal air-sending devices 1 instead of including a single centrifugal air-sending device 1 . Further, the air-conditioning apparatus 10 according to Embodiment 5 includes a case 16 in which the centrifugal air-sending devices 1 and the heat exchanger 20 are housed.
  • One of the side surface portions 16 c of the case 16 is one side surface portion 16 c having a case discharge port 17 formed in the one side surface portion 16 c .
  • Another one of the side surface portions 16 c of the case 16 is another side surface portion 16 c having a case suction port 18 formed in the other side surface portion 16 c and being opposite to the side surface portion 16 c having the case discharge port 17 formed in the one side surface portion 16 c .
  • a filter that removes dust in the air may be disposed at the case suction port 18 .
  • the case discharge port 17 and the case suction port 18 are not limited to being formed in the side surface portions 16 c but may be formed in the lower surface portion 16 b and the upper surface portion 16 a.
  • the centrifugal air-sending devices 1 each include the fan 2 , the scroll casing 4 having the bell mouth 3 formed in the scroll casing 4 , and the motor 9 .
  • the motor 9 is supported by a motor support 9 b fixed to the upper surface portion 16 a of the case 16 .
  • the motor 9 has the motor shaft 9 a.
  • the air-conditioning apparatus 10 has two fans 2 attached to the motor shaft 9 a .
  • the fans 2 of the centrifugal air-sending devices 1 form a flow of air that is sucked into the case 16 through the case suction port 18 and blown out into an air-conditioned space through the case discharge port 17 .
  • the number of fans 2 which are disposed in the case 16 , is not limited to two but may be one or larger than or equal to three.
  • the centrifugal air-sending devices 1 are attached to a partition plate 19 that partitions an internal space of the case 16 into a space S 11 facing a suction side of the scroll casings 4 and a space S 12 facing a blowout side of the scroll casings 4 .
  • the heat exchanger 20 is located in a position that faces the discharge ports 42 a of the centrifugal air-sending devices 1 , and is disposed in the case 16 to be on an air trunk of air to be discharged by the centrifugal air-sending devices 1 .
  • the heat exchanger 20 adjusts the temperature and the humidity of air that is sucked into the case 16 through the case suction port 18 and blown out into the air-conditioned space through the case discharge port 17 .
  • Rotation of the fans 2 of the centrifugal air-sending devices 1 causes the air in the air-conditioned space to be sucked into the case 16 through the case suction port 18 .
  • the air sucked into the case 16 is guided to the bell mouths 3 and sucked into the fans 2 .
  • the air sucked into the fans 2 is blown out outward in radial directions of the respective fans 2 .
  • the air blown out from the fans 2 passes through the inside of the scroll casings 4 , is blown out from the scroll casings 4 through the discharge ports 42 a , and then is supplied to the heat exchanger 20 .
  • the air supplied to the heat exchanger 20 is subjected to temperature and humidity control by, during passage through the heat exchanger 20 , exchanging heat with refrigerant flowing through the inside of the heat exchanger 20 .
  • the air having passed through the heat exchanger 20 is blown out to the air-conditioned space through the case discharge port 17 .
  • the air-conditioning apparatus 10 according to Embodiment 5 includes the centrifugal air-sending device 1 according to any one of Embodiments 1 to 4. Therefore, the air-conditioning apparatus 10 can bring about effects that are similar to those of the centrifugal air-sending device 1 according to any one of Embodiments 1 to 4.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
US18/709,963 2022-01-17 2022-01-17 Centrifugal air-sending device and air-conditioning apparatus Pending US20250012292A1 (en)

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JP (1) JPWO2023135783A1 (https=)
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US2155631A (en) * 1936-06-20 1939-04-25 American Blower Corp Blower
US3093299A (en) * 1961-05-15 1963-06-11 Trane Co Centrifugal fan
DE4313617C2 (de) * 1993-04-26 1996-04-25 Kreis Truma Geraetebau Radialgebläse
JP3491313B2 (ja) * 1994-01-31 2004-01-26 松下電工株式会社 多翼ファンとこれを用いたヘアドライヤー
KR101901303B1 (ko) * 2012-01-31 2018-09-21 엘지전자 주식회사 공기조화기
JP2020029838A (ja) 2018-08-24 2020-02-27 日本電産株式会社 送風装置、及び自動車用空調装置
JP6987940B2 (ja) * 2019-04-25 2022-01-05 三菱電機株式会社 羽根車、多翼送風機、及び空気調和装置

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CN118525151A (zh) 2024-08-20
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TW202331109A (zh) 2023-08-01
EP4467814A4 (en) 2025-03-12

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