JP2010174671A - Turbofan and air-conditioning device having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a turbofan and an air-conditioning device with reduced noise and power consumption. <P>SOLUTION: In blades 22 of the turbofan 200, a disc-like main board 20, a bell-shaped shroud 21 opposed to the main board, and a plurality of blades 22 connecting between them, are provided. A rear edge of the blade 22 lags behind the front edge 23 in a rotational direction more than in a radial direction, at the outer periphery than the blade front edge 23. The blade 22 is constituted of three regions in a height direction. In a region A close to the main board 20, an inlet angle β1 of the blade front edge 23 gets larger with a distance from the main board 20. In a region C close to the shroud 21, the blade front edge 23 gets thinner while approaching the blade rear edge 24 as the blade front edge 23 gets closer to the shroud 21. In an inner face (negative pressure face) 25 of the region C, a recessed part 28 is formed to absorb a gap flow in a position corresponding to gaps g between a bell-mouth end edge 8a and the shroud end edge 21a. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a turbo fan and an air conditioner including the turbo fan, and more particularly, to a turbo fan that blows out air sucked from the rotation center direction in a direction substantially perpendicular to the rotation center, and an air conditioner including the turbo fan.

A ceiling-embedded air conditioner (or a commercial packaged air conditioner) sucks indoor air vertically upward, and blows out cooled or heated air substantially horizontally along the ceiling.
Conventionally, there has been a demand for noise reduction and power consumption reduction. For this reason, efforts have been made in the past to solve this problem by improving the impeller of a turbofan into a complicated three-dimensional shape (for example, Patent Document 1).

JP 2007-2708 (page 4-5, FIG. 3)

The turbofan disclosed in Patent Document 1 has a main plate to which a rotation shaft of a motor is fixed, a plurality of blades arranged equiangularly on the main plate, and an annular shroud arranged to face the main plate. ing. That is, one end of the wing is joined (integral molding) to the main plate, and the other end of the wing is joined (integral molding) to the shroud.
A morning glory bell mouth (not rotating) is installed to guide air to the rotating shroud. At this time, a gap (gap) having a predetermined interval is formed between the edge of the shroud and the edge of the bell mouth.
The wing has a leading edge on the side closer to the center of rotation (inner circumferential side), a rear edge on the side farther from the center of rotation (outer circumferential side), and a radial straight line connecting the center of rotation and the leading edge. The rear edge is located behind (in the direction of delay) the rotational direction. And while the cross-sectional shape parallel to the main plate is linear in the range close to the main plate, the cross-sectional shape is bent in a substantially square shape in the range close to the shroud.

  That is, the rear edge portion close to the shroud is formed in a curved shape that bends toward the suction surface (the surface that intersects with the radiation from the rotation center on the rotation center side, which corresponds to the inner peripheral surface). The air flowing on the pressure surface side smoothly flows along the curved surface. Therefore, the phenomenon of flow separation due to the generation of turbulent flow is suppressed, the flow path loss is reduced as much as possible, the occurrence of backflow vortices is prevented, and the reduction in blowing efficiency can be reduced as much as possible.

However, since the turbofan disclosed in Patent Document 1 focuses only on the flow on the suction surface side of the blade (hereinafter sometimes referred to as “inner peripheral surface side”), for the following reason, There has been a problem that the noise reduction effect and the power consumption reduction effect cannot be obtained sufficiently.
(A) It is not considered enough that the “gap flow” flowing through the gap between the shroud and the bell mouth joins the suction surface side of the blade and disturbs the flow on the blade surface. .
(Ii) In addition, the entrance angle at the leading edge of the blade (which will be described in detail later) is not sufficiently considered to cause separation on the suction surface side if it does not fit the flow at the leading edge. .
(U) In addition, although the shroud forms an air passage that gradually shrinks in the morning glory shape, the air passage is contracted and the air flow resistance (energy loss due to friction between the wall and the wind) increases. It has not been.

  The present invention solves the above-mentioned problem, taking into account the gap flow, the inlet angle at the leading edge of the blade, and the increase in ventilation resistance in the shroud, a turbofan capable of reducing noise and power consumption, And it aims at providing the air conditioning apparatus provided with this turbofan.

(1) A turbofan according to the present invention comprises a disk-shaped main plate having a bulging portion at the center and having the center as a rotation center;
An annular shroud disposed opposite the main plate;
A rear edge which is disposed between the main plate and the shroud and which is on a virtual cylinder formed by the outer periphery of the main plate and the outer periphery of the shroud, and advances in the direction of rotation with respect to the rear edge and is closer to the center of rotation. A plurality of wings having a leading edge;
Have
In a predetermined first region near the main plate of the wing, the farther away from the main plate, the gradually increasing the entrance angle of the leading edge of the wing,
In a predetermined third region of the wing close to the shroud, the closer to the shroud, the closer the leading edge of the wing gradually approaches the trailing edge, the thickness of the wing gradually decreases, and the rotation of the wing. A concave portion that is smoothly recessed is formed on the surface on the center side,
The shape of the cross section perpendicular to the rotation center at the position closest to the shroud in the first region is the same as the shape of the cross section perpendicular to the rotation center at the position closest to the main plate in the third region. In the second region sandwiched between the first region and the third region, the leading edge of the blade is parallel to the center of rotation.
(2) Moreover, the air conditioning apparatus which concerns on this invention has the housing | casing which comprises the suction inlet which breathes in air, and the blower outlet which blows off air,
The turbofan according to (1) disposed in the housing;
A motor coupled to the main plate of the turbofan;
A bell mouth for guiding air to the shroud of the turbofan;
A heat exchanger disposed around the turbofan;
It is characterized by having.

  (I) Since the turbo fan according to the present invention has the shape described above, in the first region, the deviation between the inflow angle α1 and the inlet angle β1 is corrected, and generation of separation vortices on the suction surface is suppressed. In the region, the speed increase of the air flow due to the reduction of the cross-sectional area of the ventilation path is mitigated, the energy loss due to the increase of the flow velocity is suppressed, and the concave portion where the air flow substantially parallel to the rotation center is interrupted is formed. The occurrence of turbulence and vortices in the air flow substantially perpendicular to the center of rotation is suppressed.

Sectional drawing of the side view which shows the air conditioning apparatus which concerns on Embodiment 1 of this invention. The perspective view explaining the turbo fan which concerns on Embodiment 2 of this invention. The top view which permeate | transmitted a part of turbofan shown in FIG. The top view which permeate | transmitted a part of turbofan shown in FIG. The side view which permeate | transmitted a part of turbofan shown in FIG. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. FIG. 3 is an enlarged sectional view of a part of the turbofan shown in FIG. 2. The side view for demonstrating the internal flow of the turbo fan shown in FIG. Sectional drawing of planar view for demonstrating the effect | action of the turbofan shown in FIG. Sectional drawing of planar view for demonstrating the effect | action of the turbofan shown in FIG. The performance curve figure which shows the effect of the turbo fan shown in FIG. The side view explaining the turbo fan which concerns on Embodiment 3 of this invention. FIG. 3 is a schematic cross-sectional view showing a part (a hump) of the turbo fan shown in FIG. 2 in an enlarged manner. FIG. 3 is a schematic perspective view for explaining the operation of a part (hump) of the turbo fan shown in FIG. 2. The top view explaining the effect | action of a part (hump) of the turbo fan shown in FIG. Sectional drawing explaining the effect | action of a part (hump) of the turbo fan shown in FIG. The characteristic curve figure which shows the relationship between the angle of attack and lift of the turbofan shown in FIG. The side view which shows the variation of the turbo fan shown in FIG. The perspective view explaining the turbo fan which concerns on Embodiment 4 of this invention. FIG. 24 is an enlarged cross-sectional view of a part of the turbo fan shown in FIG. 23. FIG. 24 is an enlarged cross-sectional view of a part of the turbo fan shown in FIG. 23. FIG. 24 is an enlarged cross-sectional view of a part of the turbo fan shown in FIG. 23. The perspective view which shows the part of the turbo fan which concerns on Embodiment 5 of this invention. The schematic diagram explaining the effect of the turbofan shown in FIG. The perspective view which shows the variation of the turbo fan shown in FIG.

[Embodiment 1]
FIG. 1 is a side sectional view schematically showing the air-conditioning apparatus according to Embodiment 1 of the present invention. In addition, since FIG. 1 is drawn typically, the relative magnitude relationship (including aspect ratio) of each member is not limited.

(Air conditioner)
In FIG. 1, the air conditioner 100 is embedded in a recess 901 formed in a ceiling 900 and is suspended by a bolt 903 and a nut 904 on a mounting wall 902 which is the bottom (upper surface in FIG. 1) of the recess 901. Yes.
The air conditioner 100 includes a rectangular parallelepiped housing 1 whose one surface (lower surface in FIG. 1) is open, a motor mounting member 6 fixed to a bottom (upper surface in FIG. 1) 11, and a motor mounting member 6. The motor 5 is attached, and a turbofan 200 is attached to the rotating shaft of the motor 5.

The central range of the opening (the lower surface in FIG. 1) of the housing 1 is a suction port 12 where a filter 7 is installed. An air outlet 13 is formed around the inlet 12 (the side away from the center of rotation in the horizontal plane), and a flap 9 for changing the wind direction is installed at the air outlet 13. Further, in order to guide the air sucked from the suction port 12 to the turbo fan 200, a bell mouth 8 which is gradually reduced in diameter in a roughly morning glory shape (trumpet shape) is provided.
Furthermore, the heat exchanger 4 is installed around the turbofan 200 (on the side away from the rotation center in the horizontal plane).

(Turbo fan)
The turbo fan 200 includes a disc-shaped main plate 20 having a main plate bulging portion 20a at the center, a plurality of blades 22 arranged at an equal angle with respect to the center of rotation, and an annular shape arranged at a predetermined interval from the main plate 20. And the shroud 21. That is, one end of the wing 22 is joined (integral molding) to the main plate 20, and the other end of the wing 22 is joined (integral molding) to the shroud 21.
At this time, the side (motor 5 side) where the blades 22 of the main plate swelling portion 20a are not joined is a cavity, and the motor 5 is housed in the cavity.

The edge of the bell mouth 8 having the smallest inner diameter (same as the edge on the turbofan 200 side, hereinafter referred to as “bell mouth edge”) 8a has the diameter of the shroud 21 having the smallest inner diameter (the bell mouth 8 side). Is smaller than the diameter of 21a). Since the bell mouth edge 8a penetrates into the shroud 21, a predetermined gap (hereinafter referred to as "gap") is formed between the bell mouth edge 8a and the shroud edge 21a in the radial direction of the rotation center. ) G is formed, and a predetermined distance in the rotation center direction overlaps.
The diameter of the outer periphery 21b of the shroud 21 is the same as the diameter of the outer periphery 20b of the main plate 20.

(Air flow)
Next, the operation of the air conditioning apparatus 100 will be described. In FIG. 1, when the turbo fan 200 rotates, the sucked air becomes a suction flow W <b> 1 and passes through the filter 7 and is removed. Then, after being guided to the turbo fan 200 by the bell mouth 8 and becoming the internal flow W2 of the turbo fan, it is blown out to the surroundings. Further, the air is cooled or heated to a predetermined temperature in the heat exchanger 4 to become a conditioned air flow W4. And it becomes the blowing flow W5 which is orient | assigned to the predetermined direction by the flap 9 and blows off into the room | chamber interior from the blower outlet 13. FIG.

  Further, since the gap g is formed between the bell mouth edge 8a and the shroud edge 21a, a gap flow W3 flowing through the gap g is generated. That is, a part of the air blown out from the turbofan to the surroundings does not pass through the heat exchanger 4 but passes through the gap g and is sucked into the internal flow W2.

Since the turbo fan 200 mounted on the air conditioner 100 has a configuration described in detail in the second embodiment, even if the internal flow W2 passes between the blades 22 while being bent at a substantially right angle, the blades Vortex due to flow separation hardly occurs on the surface 22, noise is suppressed, and a reduction in blowing efficiency is prevented.
Further, the gap flow W3 joins the internal flow W2 from the middle, but the occurrence of turbulence on the surface of the blade 22 is minimized.
That is, the air conditioner 100 is designed to reduce noise (silent operation) and save energy.
In the above description, the air conditioner 100 is described as a ceiling-embedded business packaged air conditioner. However, the present invention is not limited to this, and the turbo fan described in the second embodiment is used even for home use. The type is not limited as long as the air conditioner is used. Further, in place of the heat exchanger 4, other air conditioning means such as dehumidifying / humidifying means, dust or bacteria removing means, ozone or fragrance adding means may be installed.

[Embodiment 2]
2 to 10 illustrate a turbo fan according to Embodiment 2 of the present invention. FIG. 2 is a perspective view, FIGS. 3 and 4 are partially transparent plan views, and FIG. 6 to 11 are cross-sectional views in plan view showing a part thereof enlarged, FIG. 12 is a side view showing the internal flow, and FIGS. 13 and 14 are diagrams for schematically explaining the operation. FIG. 15 is a performance curve diagram showing the effect.

(Turbo fan)
In FIG. 2, a turbofan 200 is mounted on the air conditioner 100 (Embodiment 1), and includes a disk-shaped main plate 20 and a morning glory shape (a trumpet) arranged at a predetermined interval from the main plate 20. And a plurality of blades 22 having one end connected to the main plate 20 and the other end connected to the shroud 21 (integral molding).
Seven blades 22 are arranged equiangularly in the circumferential direction, but the present invention does not limit the number. In the blade 22, the blade leading edge 23, which is an edge near the rotation center O (O), advances in the rotation direction (indicated by an arrow) more than the blade trailing edge 24, which is an edge far from the rotation center O (O). Located in the direction. That is, the blade trailing edge 24 is located on the delay side in the rotational direction with respect to the blade leading edge 23.

The center of the main plate 20 rises to form a main plate bulge portion 20a. A motor 5 (not shown) is disposed in a cavity formed by the main plate bulge portion 20a, and cooling air passes through the main plate bulge portion 20a. A main plate cooling hole 20c is formed.
The shroud 21 has air that flows in from the small-diameter side of the morning glory (trumpet-shaped), and air flows out from the large-diameter side, but the large-diameter side faces the main plate 20, and therefore the airflow path through which air flows Is configured such that the distance parallel to the rotation center O is gradually narrowed and the cross-sectional area is narrowed.

(Entrance angle)
Before describing the detailed shape of the blade 22, the definitions of the inlet angle and the inflow angle will be described in advance. For convenience of the following description, the main plate 20 side at the rotation center O is defined as “−Z direction or downward direction”, and the shroud 21 side at the rotation center O is defined as “+ Z direction or upward direction”. Further, the radiation direction from the rotation center O is “r-axis”, the radiation direction away from the rotation center O is “+ r direction or outward direction”, and the radiation direction toward the rotation center O is “−r direction or inward direction”. To do. Further, an axis perpendicular to the r axis is defined as “θ axis”. A plane perpendicular to the rotation center O is referred to as “horizontal or horizontal direction”.

FIG. 3 is a cross-sectional view of the blade 22 cut at a predetermined position in the Z direction, and a point Q is set at the blade leading edge 23 of the blade 22. A surface (hereinafter referred to as “inner surface or suction surface”) 25 closer to the rotation center O of the blade 22 and a surface far from the rotation center O of the blade 22 (hereinafter referred to as “outer surface or pressure surface”) 26. A chord center line 31 is defined as a line segment that is continuously connected to the midpoint (the same as the midpoint of the blade thickness).
The angle formed between the straight line 32 obtained by extending the chord centerline 31 at the Q point and the θ axis at the Q point is defined as “entrance angle β1”.
That is, when the entrance angle β1 is 0 °, the direction of the chord centerline 31 at the Q point coincides with the θ axis, and when the entrance angle β1 is 90 °, the direction of the chord centerline 31 at the Q point is the r axis. Matches. Therefore, as the entrance angle β1 increases, the direction of the chord centerline 31 at the point Q becomes closer to the radial direction, so the entrance angle β1 is a guideline indicating “the degree that the wing is standing”.

(Inflow angle)
Next, the inflow angle will be described. FIG. 4 is a cross-sectional view of the blade 22 cut at a predetermined position in the Z direction, and a point P is set on the upstream side (rotation center O side) in the vicinity of the blade leading edge 23 of the blade 22. An air flow at the point P is defined as a velocity V, and an angle formed by the velocity V and the θ axis is defined as an “inflow angle α1”. Further, components obtained by decomposing the velocity V into the r-axis direction and the θ-axis direction at the point P are defined as Vr and Vθ, respectively.
In general, in order to carry a lot of wind, it is desirable to raise the blade (increase the entrance angle β1, that is, close to the radial direction) so that the entrance angle β1 is larger than the inflow angle α1 (β1> α1). . However, if the inlet angle β1 is made too large, a separation vortex W9 is generated on the suction surface 25 side as shown in FIG. 3A, so that noise increases and air flow decreases. When the air flow rate decreases, it is necessary to increase the rotational speed to achieve the target air volume, and the power consumption of the motor 5 increases. That is, if the air blowing efficiency is increased, the number of revolutions can be reduced, and thus power consumption can be reduced.

(Three-dimensional wing shape)
Next, the three-dimensional blade shape of the turbofan 200 will be described.
In FIG. 5, for convenience of explanation, only one blade 22 is illustrated. The wings 22 are sequentially arranged in a height direction (from the −Z direction to the + Z direction) in a region A (corresponding to the first region), a region B (corresponding to the second region), and a region C (corresponding to the third region). (Corresponding) three regions.
The cross-sectional shape of the region A and the region C changes in the height direction, and the cross-sectional shape of the region B is substantially constant in the height direction. That is, the uppermost part of region A (same as the lowest part of region B) is substantially the same as the lowest part of region C (same as the uppermost part of region B).

The area A is horizontally divided into two, and the lowermost section (position closest to the main plate 20) is the A1 section, the middle section is the A2 section, and the uppermost section is the A3 section.
Further, the region C is horizontally divided into four, and the lowermost cross section is defined as a C1 cross section, which are sequentially defined as a C2 cross section, a C3 cross section, and a C4 cross section.
Since the lowermost portion of the region B is the same as the A3 cross section and the uppermost cross section is the same as the C1 cross section, the A3 cross section and the C1 cross section are substantially the same.
Further, the outer diameter D8 of the bell mouth edge 8a of the bell mouth 8 is smaller than the inner diameter D21 of the shroud edge 21a of the shroud 21 (D8 <D21), and the bell mouth edge 8a enters the shroud 21 and both A gap g is formed between them.

(A area)
In FIG. 6, the A1 cross section, the A2 cross section and the A3 cross section are drawn to overlap each other, and a gap g (gap between the outer diameter D8 of the bell mouth end edge 8a and the inner diameter D21 of the shroud end edge 21a is formed. The space in which no exists is indicated by diagonal lines.
As the position of the cross section becomes higher (in the + Z direction), that is, the entrance angle β1 is gradually increased in the A2 cross section than in the A1 cross section and in the A3 cross section than the A2 cross section. (Β1 (A1) <β1 (A2) <β1 (A3)). That is, the closer to the main plate 20, the smaller the entrance angle β1. The A3 cross section employs the NACA-65 series cascade widely used in aircraft and the like.

(B area)
The region B (not shown) has a constant shape regardless of the position of the cross section, and is configured as a two-dimensional wing substantially upright with respect to the main plate 20. That is, the same cross section as the A3 cross section adopts a NACA-65 series cascade that has been widely used in aircrafts and the like.

(C area)
In FIG. 7, the C1 to C4 cross sections are overlapped, and a gap g formed between the outer diameter D8 of the bell mouth edge 8a and the inner diameter D21 of the shroud edge 21a (actually a gap, and a member exists) (Not space) is indicated by diagonal lines. Further, a virtual circle 91 (hereinafter referred to as a “concave portion start circle”) having a diameter smaller than the outer diameter D8 of the bell mouth edge 8a around the rotation center O by twice the gap g, and the rotation center O as the center. An imaginary circle 92 (hereinafter referred to as a “concave portion end circle”) having a diameter that is twice as large as the gap g than the inner diameter D21 of the shroud edge 21a is shown by a two-dot chain line.

As the position of the cross-section increases (in the + Z direction), the blade 22 gradually decreases in thickness while the blade leading edge 23 gradually retracts toward the blade trailing edge 24, and the blade leading edge 23 and The distance from the wing trailing edge 24 is shortened. At this time, the inlet angle β1 at the blade leading edge 23 is substantially constant regardless of the position of the cross section.
In FIG. 7, the Cj cross section has a leading edge 23 (Cj), a trailing edge 24 (Cj), a blade inner surface 25 (Cj), and a blade outer surface 26 (Cj) (j = 1 to 4).
That is, the blade leading edge 23 (C1), the blade leading edge 23 (C2), the blade leading edge 23 (C3), and the blade leading edge 23 (C4) approach the outer direction in this order and are delayed with respect to the rotation direction. Is located. On the other hand, the blade trailing edge 24 (C1), the blade trailing edge 24 (C2), the blade trailing edge 24 (C3), and the blade trailing edge 24 (C4) approach inward in this order, and advance in the rotational direction. Is located.
Hereinafter, the Cj cross section will be described in detail.

(C1 cross section)
In FIG. 8, the C1 cross section is substantially the same as the A3 cross section, that is, substantially the same as the cross section of the B region. The blade leading edge 23 (C1) is substantially at the same position as the region A and the region B with respect to the rotation center O, and the blade trailing edge 24 (C1) coincides with the outer periphery 20b of the main plate 20.
The inner surface (negative pressure surface) 25 (C1) has a smooth concave surface that is concave on the inner side (rotation center O side), and the outer surface (same as the positive pressure surface) 26 (C1) swells outward (in the direction away from the rotation center O). Exhibits a convex surface. The range corresponding to the gap g is a thick range.

(C2 cross section)
In FIG. 9, the blade C2 cross section is at a position where the blade leading edge 23 (C2) is outside the blade leading edge 23 (C1) and delayed with respect to the rotational direction, and the blade trailing edge 24 (C2) is the blade trailing edge 24 ( In the same position as C1).
The blade inner surface 25 (C2) has a concave portion 28 (C2) formed between the concave portion start circle 91 and the concave portion end circle 92. That is, a virtual surface 27 (C2) smoothly connecting the range of the blade inner surface 25 (C2) near the blade leading edge 23 (C2) and the range of the blade inner surface 25 (C2) near the blade trailing edge 24 (C2). On the other hand, the actual blade inner surface 25 (C2) lacks a range indicated by hatching and is recessed.
The concave portion 28 (C2) has the deepest range corresponding to the gap g (corresponding to a position immediately below between the bell mouth edge 8a and the shroud edge 21a), and the concave portion 28 (C2) is smooth from the position of the concave portion start circle 91 toward this. From then on, it becomes shallower smoothly toward the position of the concave end circle 92.

(C3 cross section)
In FIG. 10, the C3 cross section is at a position where the blade leading edge 23 (C3) is outside the blade leading edge 23 (C2), that is, slightly outside the concave portion start circle 91 and delayed from the rotational direction.
Further, since the blade trailing edge 24 (C3) is joined to the reduced diameter range 21c of the shroud 21, it is located closer to the inner diameter than the main plate outer periphery 20b of the main plate 20.
The wing inner surface 25 (C3) has a concave portion 28 (C3) formed between the bell mouth edge 8a and the concave portion end circle 92. That is, a virtual surface 27 (C3) that smoothly connects the range near the blade leading edge 23 (C2) of the blade inner surface 25 (C3) and the range near the blade trailing edge 24 (C3) of the blade inner surface 25 (C2). On the other hand, the actual blade inner surface 25 (C3) lacks a range indicated by hatching and is recessed.
The concave portion 28 (C2) is deepest at a position substantially corresponding to the bell mouth edge 8a, and smoothly becomes deeper from a position corresponding to the bell mouth edge 8a toward the concave mouth 28 (C2). Smooth and shallow.

(C4 cross section)
In FIG. 11, the C4 cross section is at a position where the wing leading edge 23 (C4) is outside the wing leading edge 23 (C3), that is, outside the position corresponding to the bell mouth edge 8a and delayed with respect to the rotation direction. is there.
Further, since the blade trailing edge 24 (C4) is joined to the reduced diameter range 21d of the shroud 21, it is located closer to the inner diameter than the outer periphery 20b of the main plate 20.
The blade inner surface 25 (C4) has a concave portion 28 (C4) formed between the shroud edge 21a and the concave portion end circle 92.
That is, a virtual surface 27 (C4) smoothly connecting the range near the blade leading edge 23 (C4) of the blade inner surface 25 (C4) and the range near the blade trailing edge 24 (C4) of the blade inner surface 25 (C4). On the other hand, the actual blade inner surface 25 (C4) lacks a range indicated by hatching and is recessed. The concave portion 28 (C4) has a substantially square cross section, and gradually becomes deeper from a position substantially corresponding to the bell mouth edge 8a, and smoothly becomes shallower toward a position corresponding to the concave portion end circle 92.
The concave portion 28 (C2), the concave portion 28 (C3), and the concave portion 28 (C4) (hereinafter, these may be collectively referred to as “concave portion 28”) form a smoothly connected curved surface. To do.

(Operation)
Next, the operation of the turbo fan 200 will be described.
FIG. 12 is a side view for schematically explaining the internal flow of the turbofan 200.
In FIG. 12, an internal flow W2 that is an air flow that flows into the shroud 21 from the bell mouth edge 8a includes an air flow W20 that flows in a region A close to the main plate 20, an air flow W22 that flows in a region C close to the shroud 21, It can be divided into the air flow W21 flowing through the region B sandwiched between the two.

(Area A)
The air flow W20 in the region A has a wall surface frictional force in the vicinity of the main plate 20, so that the closer to the main plate 20 (the same as the wall surface), the slower the flow velocity. The inventors conduct numerical fluid analysis to investigate the internal flow W2 (particularly, air flow W20) of the turbofan 200 in detail, and the blade leading edge 23 (particularly the blade leading edge 23 (A1), the blade leading edge 23). (A2) When the inflow angle α1 at the blade leading edge 23 (A3)) was analyzed, it was found that the inflow angle α1 became smaller as the main plate 20 was approached.
And since the inlet angle (beta) 1 of the blade front edge 23 in the area | region A is so small that the turbofan 200 approaches the main plate 20, the shift | offset | difference of the inflow angle (alpha) 1 and the inlet angle (beta) 1 in the vicinity of the main plate 20 is corrected, The separation vortex W9 on the suction surface (outer surface) side is not generated.

(Region C)
Further, in the region C, the shroud 21 is approaching the main plate 20 while expanding the diameter, so that the cross-sectional area of the ventilation path is gradually reduced toward the downstream side of the air flow W22. As the blade 22 in the region C becomes downstream of the air flow W22, the turbo fan 200 gradually decreases in thickness while the position of the blade leading edge 23 gradually recedes toward the blade trailing edge 24. For this reason, the increase in the air flow W22 due to the reduction in the cross-sectional area of the ventilation path is mitigated, and the energy loss due to the increase in the flow velocity is suppressed.

(Gap flow)
Next, the gap flow W3 that has passed through the gap g will be described.
13 and 14 schematically illustrate the influence of the gap flow W3. FIG. 13 is a sectional view in plan view of the present invention, and FIG. 14 is a sectional view in plan view for comparison.
In FIG. 13, a gap g is formed between the bell mouth edge 8a (fixed side) and the shroud edge 21a (rotation side). Then, the rotation of the turbo fan 200 generates a negative pressure on the negative pressure surface (inner surface) side of the blade 22, so that the gap flow in the direction of the main plate 20 (substantially −Z direction) sucked by the negative pressure and passing through the gap g. W3 is formed.

The gap flow W3 enters (inhales) the concave portion 28 (C4), the concave portion 28 (C3), and the concave portion 28 (C2) formed on the suction surface (inner surface) side of the blade 22 in this order. However, the air flow W22 gradually changes its direction in the horizontal direction.
At this time, since the concave portion 28 is formed, a space (wind passage) into which the gap flow W3 is interrupted is secured, and the gap flow W3 smoothly joins the air flow W22 without disturbing the air flow W22. Thus, the air flows toward the blade trailing edge 24 without generating any turbulence or vortex (the occurrence of turbulence or vortex is suppressed). Therefore, since the vortex does not collide with the heat exchanger 4 located on the outer periphery of the turbofan 200, generation of noise can be suppressed.

In FIG. 14, for comparison, the blade 922 has no concave portion on the suction surface (inner surface) 925. That is, the blade 922 smoothly connects the range of the inner surface 925 near the front edge 923 and the range near the rear edge 924.
At this time, since the concave portion 28 as described above is not formed, the gap flow W3 in the direction of the main plate 20 (substantially in the −Z direction) gradually changes in the horizontal direction because there is no space for interruption. Collides with the air flow W22. Then, the air flow W22 is greatly disturbed by the air flow W7 whose flow direction is abruptly changed, and a vortex W8 is generated by merging with the gap flow W3. When the vortex W8 collides with the heat exchanger 4 located on the outer periphery of the turbofan 200, noise is generated.

(Region B)
Since the region B is hardly affected by the deviation of the inflow angle α1 in the region A and the speed increase due to the gap flow W3 and the contracted flow in the region C, a stable two-dimensional flow is formed along the blade 22; Air is blown efficiently.

As described above, in the turbofan 200, the blade shape in a cross section (corresponding to a horizontal cross section) orthogonal to the rotation center O is the blade leading edge from the main plate 20 side toward the shroud 21 side (to the + Z direction). A region A where the inlet angle β1 of the blade 23 gradually increases, a region B where the inlet angle β1 of the blade leading edge 23 is constant and substantially upright with respect to the main plate 20, and the position of the blade leading edge 23 of the blade 22 is The wing 22 is gradually retracted toward the trailing edge 24, and the thickness of the wing 22 is gradually reduced. Further, the wing inner surface 25 of the wing 22 is recessed in the middle of the wing leading edge 23 and the wing trailing edge 24. And a region C in which is formed.
For this reason, in the region A, the separation vortex W9 on the inner surface (negative pressure surface) side due to the deviation between the inflow angle α1 in the vicinity of the main plate 20 and the inlet angle β1 at the blade leading edge 23 is suppressed.
In the region B, highly efficient and stable air blowing is realized.
Furthermore, in the region C, it is possible to reduce the disturbance due to the gap flow W3 joining the air flow W22 flowing through the inner surface (negative pressure surface) 25 and the increase in energy loss due to the increase in speed due to the shape of the shroud 21. The noise and power consumption of the air conditioner can be reduced.

(Noise reduction effect)
FIG. 15 explains the noise reduction effect of the air-conditioning apparatus according to Embodiment 1 of the present invention (in which the turbo fan according to Embodiment 2 of the present invention is mounted).
In FIG. 15, the vertical axis represents the actually measured noise value, the horizontal axis represents the frequency, and the measured noise value in the case of the turbofan 200 having the blades 22 formed with the concave portions 28 is referred to as a “developed product” and is a thin solid line. The measured value of noise in the case of a turbofan having blades in which the concave portion 28 is not formed is referred to as “conventional product” and indicated by a thick solid line.
The noise measurement was performed by installing a microphone at a position 1 m from the suction port 12. Compared to the conventional 47.1 [dBA], the developed product of Embodiment 1 is 45.9 [dBA], and the noise of 1.2 [dBA] could be reduced.
As for the ventilation efficiency, the air volume at the same rotation speed increased 1.06 times in the developed product. As a result, the amount of power consumption required to blow the same air can be reduced by about 6%.

(Numerical fluid analysis)
In addition, about the internal flow W2 of a turbofan, detailed investigation was implemented using the numerical fluid analysis (CFD: Computational Fluid Dynamics). The software was STAR-CD, and the analysis model was created based on a three-dimensional CAD database. The number of analysis grids was about 2 million, the time step of one rotation was 336, and unsteady calculation was performed with sufficient resolution in terms of time and space. In order to verify the validity of the numerical analysis, the wind speed value at the outlet was compared with the measured results, and it was confirmed that they were almost the same.
Although the blade shape in the region B is NACA-65, the present invention is not limited to this, and the same effect can be obtained even if another highly efficient blade shape is employed.
In addition, although the region B is described as a substantially upright shape with respect to the main plate 20, if a slight draft is required in the resin molding manufacturing, the region B is slightly allowed and slightly inclined to correspond to the draft. May be. The draft angle is about 1 ° in this case, although there is a difference depending on the material of the resin forming the blade 22.

[Embodiment 3]
FIGS. 16 to 22 illustrate a turbo fan according to Embodiment 3 of the present invention. FIG. 16 is a side view through which a part is transmitted, and FIG. 17 is an enlarged cross section of a part (hump). FIG. 18 is a schematic perspective view for schematically explaining the action of a part (gump), and FIG. 19 is a plan view through which part of the action is schematically explained. 20 is a cross-sectional view in side view schematically explaining the action of a part (gump), FIG. 21 is a characteristic curve diagram showing the relationship between the angle of attack and lift, and FIG. 22 is a side view through a part showing variation. FIG. In addition, the same code | symbol is attached | subjected to the part which is the same as that of Embodiment 2, or an equivalent part, and one part description is abbreviate | omitted.

(Turbo fan)
In FIG. 16, a turbofan 300 is mounted on the air conditioner 100 (Embodiment 1) and has blades 322. The blade 322 is formed with a plurality of “humps 50” protruding toward the upstream side of the air flow W2 on the blade leading edge 23 in the region C of the blade 22 of the turbo fan 200 (Embodiment 2).
The tip of the hump 50 is a part of a sphere or a bulge-like bulge, and the slope becomes gentler as it goes to the skirt, and the adjacent humps 50 along the wing leading edge 23 are smoothly connected at the end of the skirt. ing.
FIG. 17 schematically illustrates the hump 50, and a plane (position A, position B, position H) from the position “I”, which is the apex of the hump 50 (the top of the raised portion), toward the blade trailing edge 24. And a plane cut along a plane (including position d, position e, and position f) from the position “d” where the skirts of the hump 50 are joined to each other to the blade trailing edge 24.

(Air flow on the inner surface)
18 and 19 schematically illustrate the air flow on the inner surface 25 (same as the suction surface). FIG. 18 (a) is a perspective view, and FIG. 18 (b) is from the front edge to the rear. FIG. 19A is a sectional view in plan view, and FIG. 19B is a sectional view in plan view for comparison.
In FIG. 18, the air flow W22 is formed with a plurality of small (narrow range) vertical vortices W61 and vertical vortices W62 by a hump 50 installed on the blade leading edge 23.
That is, when the hump 50 is not installed on the blade leading edge 23, the air flow W22 is divided into the inner surface (negative pressure surface) 25 and the outer surface (positive pressure surface) 26, and the inner and outer surfaces (substantially secondary surface). When the hump 50 is installed on the leading edge 23, the air flow W <b> 22 is divided by the hump 50 in the direction of the inside and outside and the blade leading edge 23 (in the tertiary plane).

At this time, the air flow along the curved surface (same as the slope on the right side with respect to the vertex in FIG. 18B) surrounded by the position a, the position b, the position d, and the position e is rotated forward (clockwise). The vertical vortex W62 is formed in the direction of the blade trailing edge 24. That is, the vertical vortex W62 becomes a “forward rotating vertical vortex” which is a swirling flow having a rotation center in the flow direction.
On the other hand, the vertical vortex W61 along the curved surface (same as the slope on the left side with respect to the apex in FIG. 18B) surrounded by the positions A, B, G and H is “negative positive rotation ( It becomes a vertical vortex ".

In FIG. 19A, when the hump 50 is present, the blade inner surface 25 is formed with spiral longitudinal vortices W61 and W62 whose rotation directions are alternately changed over a plurality of rows. Even if separation of the air flow occurs, the separation flow is caught in the vertical vortex, so that generation of turbulent flow accompanying separation is suppressed. Therefore, the generation of noise in the air conditioner equipped with the turbo fan 300 can be suppressed.
On the other hand, in FIG. 19B, when there is no hump 50, separation is not suppressed, and turbulent flow W63 is generated. Therefore, an air conditioner equipped with the turbulent flow W63 may generate noise.

(Lift acting on the inner surface)
Next, the lift acting on the blade inner surface 25 when the hump 50 is present will be described.
FIG. 20A shows a case where the hump 50 is not installed on the blade leading edge 23 (two-dimensional blade), and the main flow direction 56 of the air flow W22 and the thickness chord centerline of the blade 22 are shown. The angle formed by the extending direction 57 at the blade leading edge 23 of 31 is “attack angle η”, and the lift acting on the inner surface (negative pressure surface) 25 is “lift L”.
FIG. 21 shows the relationship between the angle of attack and the lift force. The vertical axis represents the lift coefficient obtained by making the lift L dimensionless, and the horizontal axis represents the angle of attack η. When the angle of attack η is increased, the lift increases, but peeling occurs on the suction surface side and the lift starts to decrease. It is known that the peak of the lift coefficient is normally 15 to 20 degrees, and in this case, it was about 16 degrees.

In FIG. 20 (b), when the hump 50 is installed on the blade leading edge 23, as described above, a plurality of vertical vortices whose rotational directions are alternately changed are formed, so that peeling is suppressed, Such a plurality of longitudinal vortices have an action of entraining a high-speed flow having a relatively high flow velocity flowing in a place away from the surface and moving it close to the surface, so that generation of vortices (turbulent flow) can be suppressed.
For this reason, by attaching the hump 50 to the leading edge 23 of the blade 22, even when the angle of attack η is increased, the blade 22 can be prevented from stalling and the lift L can be increased. Note that the angle of attack η in the case of the turbofan 300 corresponds to the difference (η = α1−β1) between the inflow angle α1 and the inlet angle β1.

  As described above, the turbofan 300 is provided with the plurality of bumps 50 at the blade leading edge 23 of the blade, so even when the deviation between the inlet angle β1 and the inflow angle α1 is large, the turbofan 300 is located on the inner surface (negative pressure surface) 25 side. Separation is suppressed and no large-scale vortex (W9) is generated. Therefore, in the air conditioner equipped with the turbo fan 300, noise and power consumption can be reduced.

(Other forms)
FIG. 22 is a partially transparent side view illustrating a variation of the turbofan according to Embodiment 3 of the present invention. In FIG. 22, the turbo fan 310 has a blade 322 b in which a hump 50 is installed on the entire blade leading edge 23. At this time, the same effect as the turbofan 300 is obtained in the entire region (region A, region B, and region C) of the blade 22.
Note that the present invention is not limited to the form of the turbofan illustrated, and for example, the hump 50 may be installed in the region A and the region C of the blade 22.
Further, the shape (size, protrusion amount, sharpness of the apex, etc.) and interval of the hump 50 are not limited, and the vertical vortices W61 and W62 can be generated on the inner surface (negative pressure surface) 25 side to suppress separation. If it is a thing, the height and the width of the mountain are not asked. Moreover, although it described arrange | positioning at equal intervals, there exists an equivalent effect even if an interval is random.

[Embodiment 4]
FIGS. 23 to 26 illustrate a turbo fan according to Embodiment 4 of the present invention. FIG. 23 is a perspective view, and FIGS. is there. In addition, the same code | symbol is attached | subjected to the part which is the same as that of Embodiment 2, or an equivalent part, and one part description is abbreviate | omitted. Further, in FIG. 23, an interval (an interval parallel to the rotation center O) between the shroud outer periphery 21b and the main plate outer periphery 20b is “h”.
The turbofan 400 has wings 422. The blade 422 has the same shape as the blade 22 of the turbofan 400 (Embodiment 2) in the range of “0.5 h” close to the main plate 20. Further, the range of the blades 422 close to the blade leading edge 423 is the same as the shape of the range close to the blade leading edge 23 in the range (total height) from the main plate 20 to the shroud 21.

However, the blade trailing edge 424 of the blade 422 is closer to the shroud 21 than the trailing edge 24 of the blade 22 in the range closer to the shroud 21 than the height “0.5 h” from the main plate 20 (corresponding to the fourth region). Is also formed so as to be delayed with respect to the rotation direction.
That is, the trailing edge 24 of the blade 22 is parallel to the rotation center O, and is located on the line connecting “position” and “position” in FIG. On the other hand, the trailing edge 423 of the wing 422 is higher than the “position” of the height “0.5 h” from the main plate 20, and is delayed with respect to the rotation direction as it approaches the shroud 21. Connected to. Here, in a plan view, an angle φ formed by the radiation 72 passing through the “position” and the radiation 71 passing through the “position” from the rotation center O is about 8.5 ° (see FIG. 24). .

24 to 26 show the shapes of the blades 422 in the C2, C3, and C4 cross sections (see FIG. 5), respectively.
For example, in the C2 cross section shown in FIG. 24, the position of the blade trailing edge 424 (C2) of the blade 422 is “position” in a plan view, whereas the blade trailing edge 24 (C2) of the blade 22 is a plan view. Therefore, since it is “position (position, position)”, it is delayed with respect to the rotation direction by an angle close to the angle φ.

(Operation)
Next, the operation will be described. The air flows that flow along the inner surface (vacuum surface side) 425 and the outer surface (pressure surface side) 426 of the blade 422 are merged at the trailing edge 423 to generate a radial direction (more precisely, a rotational direction rather than a radial direction). It is blown in the delay direction). At that time, a new disturbance occurs due to the speed difference.
However, in the blade 422 of the turbofan 400, the air flow along the inner surface (negative pressure surface side) 425 and the outer surface (pressure surface) of the blade 422 are delayed as the trailing edge 424 approaches the shroud 21. Side) 426 and the air flow along 426 are gradually mixed, and disturbance due to mixing is suppressed. Therefore, in the air conditioner equipped with the turbo fan 400, noise and power consumption can be reduced.
The range in which the blade trailing edge 424 of the blade 422 is delayed with respect to the rotation direction with respect to the rotation direction of the blade 22 (fourth region) is not limited to the shroud 21 rather than “0.5 h”. It may be wider or narrower.

[Embodiment 5]
FIGS. 27 to 29 illustrate a turbo fan according to Embodiment 5 of the present invention. FIG. 27 is a perspective view schematically showing an enlarged portion, and FIG. 28 is a schematic diagram for explaining operational effects. FIG. 29 is a perspective view showing a variation. The same parts as those in the second embodiment are denoted by the same reference numerals, and a part of the description is omitted.
In FIG. 27, the turbo fan 500 has blades 522. The blade 522 is formed with horizontal slits 80a... 80e (hereinafter sometimes referred to as “slits 80” collectively) at predetermined intervals and in five steps at a range near the main plate 20 of the blade trailing edge 24. ing.

The range closer to the main plate 20 than the slit 80a, the range sandwiched between the slit 80b and the slit 80c, and the range sandwiched between the slit 80d and the slit 80e are relative to the rotation direction (indicated by arrows). The extended rear edge portion 82a, the extended rear edge portion 82b, and the extended rear edge portion 82c are formed (hereinafter sometimes collectively referred to as “extended rear edge portion 82”). ).
A strip-shaped rear edge 81a sandwiched between the slit 80a and the slit 80b, a strip-shaped rear edge 81b sandwiched between the slit 80c and the slit 80d, and a strip-shaped rear edge 81c closer to the shroud 21 than the slit 80e ( Hereinafter, they may be collectively referred to as “strip-shaped trailing edge portion 81”), and have the same shape as the blade trailing edge 24 of the blade 22.

That is, the rearmost end of the belt-like rear edge 81 is positioned on a virtual cylinder formed by the shroud outer periphery 21b and the main plate outer periphery 20b, and is “position”, “position” and “position” parallel to the rotation center O. It is located on a straight line passing through.
Further, the slit 80 is cut to a straight line position that is parallel to the rotation center O and passes through “position”, “position”, and “position”. That is, in a plan view, the radiation 83 that passes “position” from the rotation center O advances by an angle φ3 in the rotation direction relative to the radiation 71 that passes “position”.
The rear end of the extended rear edge 82 is positioned on a virtual cylinder formed by the shroud outer periphery 21b and the main plate outer periphery 20b, and is “position”, “position”, and “position” parallel to the rotation center O. It is located on a straight line passing through. That is, in a plan view, the radiation 84 that passes “position” from the rotation center O is delayed from the radiation 71 that passes “position” by an angle φ4 with respect to the rotation direction.

(Operation)
FIGS. 28A and 28B are schematic views for explaining the operation and effect of the turbofan 500, wherein FIG. 28A is a perspective view showing the operation of the extended rear edge, and FIG. 28B is a plan view showing the case where there is no extended rear edge. is there.
In FIG. 28B, when the turbo fan 200 rotates, air is blown out from the blades 22 in a direction that tends to be delayed with respect to the rotational direction rather than the radial direction. At this time, the heat exchanger 4 is arranged on the outer periphery of the turbofan 200 with a predetermined interval.
Therefore, an air flow W <b> 24 swirling in a cylindrical shape is formed between the heat exchanger surface 41 on the turbo fan 200 side of the heat exchanger 4 and the turbo fan 200. The air flow W24 moves in the rotational direction along the heat exchanger surface 41 so that the cylinder rolls in contact with the heat exchanger surface 41. If it does so, the flow of the air which penetrate | invades into the heat exchanger 4 will be inhibited, and there exists a possibility that heat exchange may become inadequate or the air volume of the conditioned air flow W4 may reduce. Further, at the downstream position in the rotation direction of the heat exchanger surface 41, the vibration when the air flow W24 disappears contributes to the generation of noise.

In FIG. 28 (b), when the turbo fan 500 rotates, the rear end of the belt-like rear edge 81 and the rear end of the extended rear edge 82 are out of phase with respect to the rotation direction. The cylindrical air between the heat exchanger surface 41 of the heat exchanger 4 and the turbofan 500 by the air blown from the air, that is, the air blown from the belt-like rear edge 81 and the extended rear edge 82. A flow W81 and an air flow W82 are about to be formed.
However, since the generation positions of the air flow W81 and the air flow W82 are different, they interfere with each other and disappear or become weak. If it does so, the flow of the air which penetrate | invades into the heat exchanger 4 will become smooth, the air volume of heat exchange and the conditioned air flow W4 is guaranteed, and also generation | occurrence | production of noise is suppressed.

  The present invention does not limit the number of slits 80, the depth of cut (φ3), or the amount of extension (φ4) of the extended rear edge 82, but the depth of cut (φ3) and extension of each slit 80. The extension amount (φ4) of each of the trailing edge portions 82 may be different. Further, the range (corresponding to the fifth region) in which the slit 80 is formed may be a predetermined range of the trailing edge 24, for example, a wide range from the main plate 20 to the shroud 21.

  The extended trailing edge 82 is formed on either the turbo fan 300 (Embodiment 3, with the hump 50) or the turbo fan 400 (Embodiment 4, the blade trailing edge 24 near the shroud 21 is delayed). May be. For reference, FIG. 29 shows a turbo fan 600 in which an extended trailing edge 82 is formed on the blade trailing edge 424 of the turbo fan 400.

  According to the present invention, since noise and power consumption can be reduced, the present invention can be widely used as a turbo fan constituting a blowing means of various devices, and as various air conditioners for business use or household use.

  1: Housing, 4: Heat exchanger, 5: Motor, 6: Motor mounting member, 7: Filter, 8: Bell mouth, 8a: Bell mouth edge, 9: Flap, 12: Suction port, 13: Blow Outlet, 20: main plate, 20a: main plate bulge, 20b: main plate outer periphery, 20c: main plate cooling hole, 21: shroud, 21a: shroud edge, 21b: bell mouth outer periphery, 21c: reduced diameter range, 21d: reduced diameter range , 22: wing, 23: wing leading edge, 24: wing trailing edge, 25: wing inner surface, 26: wing outer surface, 27: virtual surface, 28: concave portion, 31: chord centerline, 32: straight line, 41: Heat exchanger surface, 56: flow direction, 57: extension direction, 71: radiation, 72: radiation, 80a: slit, 80b: slit, 80c: slit, 80d: slit, 80e: slit, 81a: strip-shaped rear edge, 81b: belt-like trailing edge , 81c: belt-shaped rear edge, 82a: extended rear edge, 82b: extended rear edge, 82c: extended rear edge, 83: radiation, 84: radiation, 91: concave part start circle, 92: concave part end circle , Α1: inlet angle, β1: inlet angle, η: angle of attack, φ3: angle, φ4: angle, 100: air conditioner (Embodiment 1), 200: turbo fan (Embodiment 2), 300: turbo Fan (Embodiment 3), 310: Turbo fan (Embodiment 3), 322: Blade, 322b: Blade, 400: Turbo fan (Embodiment 4), 422: Blade, 423: Blade leading edge, 424: Wing trailing edge, 500: Turbo fan (Embodiment 5), 522: Wing, 600: Turbo fan (Embodiment 5), 900: Ceiling, 901: Recess, 902: Wall, 903: Bolt, 904: Nut, O: rotation center, W1: suction flow, W2: Partial flow, W20: Air flow, W21: Air flow, W22: Air flow, W24: Air flow, W3: Gap flow, W4: Harmonic air flow, W5: Blowing flow, W61: Longitudinal vortex, W62: Longitudinal vortex, W63 : Turbulent flow, W8: Vortex, W81: Air flow, W82: Air flow, W9: Separation vortex, g: Gap.

Claims (6)

A disk-shaped main plate having a bulge at the center and having the center as the center of rotation;
An annular shroud disposed opposite the main plate;
A rear edge which is disposed between the main plate and the shroud and which is on a virtual cylinder formed by the outer periphery of the main plate and the outer periphery of the shroud, and advances in the direction of rotation with respect to the rear edge and is closer to the center of rotation. A plurality of wings having a leading edge;
Have
In a predetermined first region near the main plate of the wing, the farther away from the main plate, the gradually increasing the entrance angle of the leading edge of the wing,
In a predetermined third region of the wing close to the shroud, the closer to the shroud, the closer the leading edge of the wing gradually approaches the trailing edge, the thickness of the wing gradually decreases, and the rotation of the wing. A concave portion that is smoothly recessed is formed on the surface on the center side,
The shape of the cross section perpendicular to the rotation center at the position closest to the shroud in the first region is the same as the shape of the cross section perpendicular to the rotation center at the position closest to the main plate in the third region. In the second region sandwiched between the first region and the third region, the front edge of the blade is parallel to the center of rotation. Air flows into the shroud from a bell mouth arranged with a predetermined gap substantially parallel to the center of rotation,
From the space formed by the outer periphery of the main plate, the outer periphery of the shroud, and the trailing edge of the blade, air flows in and out substantially perpendicularly to the rotation center,
The turbofan according to claim 1, wherein the concave portion is formed at a position corresponding to a gap between an outer periphery of the shroud and an inner periphery of the bell mouth.   The turbofan according to claim 1 or 2, wherein a plurality of bumps are installed in a predetermined range of a front edge of the blade.   The trailing edge of the wing gradually recedes in a direction opposite to the rotation direction as it approaches the shroud at least in a predetermined fourth region close to the shroud. The turbo fan as described in any one.   The trailing edge of the blade is divided by the slit at one position of the trailing edge divided by a plurality of slits formed substantially perpendicular to the rotation center at least in a predetermined fifth region close to the main plate. The turbofan according to claim 1, wherein the other position of the trailing edge is different. A housing having a suction port for sucking air and a blow-out port for blowing air;
The turbo fan according to any one of claims 1 to 5 disposed in the housing;
A motor coupled to the main plate of the turbofan;
A bell mouth for guiding air to the shroud of the turbofan;
A heat exchanger disposed around the turbofan;
An air conditioner characterized by comprising:

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