ES2686246T3 - Turboventilator and air conditioner - Google Patents

Abstract

A turbo fan comprising: a disk-shaped main plate (2) having an elevation (2a) that is a fixed piece to which a rotational shaft (O) of an engine is secured; an annular side plate (3) having a side plate opening formed in the center thereof and forming a wind guide wall together with the main plate (2); and a plurality of blades (4) mounted to extend between the main plate (2) and the side plate (3); in a plan view of the blade (4), each blade (4) is positioned further away from the rotational tree (O), when it comes from a blade leading edge (4a) to a blade leading edge (4e); wherein an outer circumferential surface (4b) and an inner circumferential surface (4c) of the blade (4) at the blade leading edge (4a) have a central region in the height direction substantially parallel to the rotational shaft (O), characterized in that the blade has a skirt area near the main plate (2) that is located radially further away from the main plate (2) when approaching the main plate (2) at the blade leading edge ( 4a), and another skirt area near the side plate (3) that is located radially further out of the side plate (3) when approaching the side plate (3) at the blade leading edge (4a) , and the outer circumferential surface of the blade (4b) of the blade leading edge (4a) on the side of the main plate (2) is curved out of the main plate (2).

Description

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DESCRIPTION

Turbo fan and air conditioner Technical field

The present invention relates to a turbo fan and an air conditioner, and, more particularly, to a turbo fan for use in an air conditioner for purposes of air cleaning, humidification, dehumidification, cooling, or heating and with an apparatus air conditioner provided with it. Prior art

(A) A turbo fan having a fan blade formed in a three-dimensional shape is widely used for a blower fan that is mounted in a conventional ceiling-type air conditioning apparatus.

For example, a turbo fan is described which has a blade inlet diameter that gradually increases towards a side plate side from a main plate side, which has an inlet diameter at an inner end of a blade side plate that is larger than an inlet diameter of a side plate and having an upper end of the blade tilted in a rotational direction of an impeller, and a turbo fan in which an inclination angle between the rotational axis of the impeller and the upper end of the blade is set to a greater angle at a position closer to the outer impeller circumference than to the inner impeller circumference, while the inclination angle is set at a smaller angle in the vicinity of the side plate, in a cross-sectional view taken in the form of a concentric cylinder with the impeller shaft (see patent document 1, for example).

The turbo fan according to this arrangement prevents an air flow from an upper blade end from separating on a surface of negative blade pressure as well as prevents degradation in air blowing performance and an increase in the noise level due to turbulent flow.

(B) Also, as another conventional example, a turbo fan is described in which the position of a joined piece of side plate side of a blade outlet edge is displaced from a joined piece of side of main plate in a rotational direction opposite of the impeller a predetermined distance, and at the same time the position of a piece attached to the side of the side plate of a leading edge of the blade moves from the piece connected to the side of the main plate in a rotational direction of the impeller a predetermined distance (see patent document 2, for example).

The turbo fan according to this arrangement allows a blade pressure surface to be knocked towards the side plate side at the blade exit edge, which causes a force exerted by the pressure surface in the air to rest against the side plate, preventing the separation of air flow on the outlet side of the side plate. Additionally, it extends a length of blade rope on the side of the blade side plate that has a higher flow rate at the blade leading edge, which causes air flow to enter the blade leading edge near the plate main to the head on the side plate side and prevents separate flow from occurring on the outlet side of the blade side plate, thereby homogenizing the wind speed distribution on the front face side of the heat exchanger arranged waters below the impeller in the entire vertical region.

(C) In addition, a turbo fan is described having an end joined with the side plate moved in the rotational direction relative to an end connected with the main plate in a region from the leading edge to the exit edge, and having the side plate end on the leading edge side of the blade tilted towards the rotational direction, a turbo fan having the side plate end on the leading edge side of the blade tilted radially inward in the rotational direction with a greater angle of tilt (entry angle a) on the central side than on the sides of the main and side plate or a smaller angle of inclination on the side of the side plate than on the side of the main plate, and a turbo fan having the plate end side at the edge of the blade edge tilted radially outward in the opposite rotational direction with a greater angle of inclination (exit angle p) on the central side than on the l main and side plate plates (see patent document 3, for example).

The turbo fans according to these arrangements cause the side plate side end of the blade leading edge having a particularly greater velocity component in the axial direction of the inlet air to be tilted in the rotational direction to follow the air inlet direction , thereby safely preventing a separation that easily forms in the opposite rotational direction of the blade and consequently providing better performance and reduced noise levels. Also, a greater angle of inclination to the leading edge side in the center allows air to be taken very smoothly from the inner circumferential side. In addition, if an angle of inclination a on the side of the side plate is smaller than on the side of the main plate, air can be taken gently as the blade is formed to follow the inlet angle. At the blade exit edge, a greater inclination angle (exit angle p) on the central side than on the sides of the main and side plate allows homogenization of blown air on the outer circumferential side.

[Patent document 1] Japanese patent application pending review publication No. 10-30590 (page 4, figure 8)

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[Patent document 2] Japanese patent No. 2701604 (page 4, figure 3)

[Patent document 3] Japanese patent No. 3861008 (page 7, figure 4)

Description of the invention Problems to be solved by the invention

However, a turbo fan and an air conditioner described in patent documents 1 to 3 have the following problems.

(A) A turbo fan described in patent document 1 has assembly difficulty. That is, at least in the case of a turbo fan in which an impeller is formed integrally after molding a blade and a side plate separately and joining them to a unit by welding or fitting, if an upper blade end is tilted in the direction Rotational impeller, such a tilted upper end causes an effort exerted on the joined piece of main plate, to prevent a force from being properly applied to the side plate, because the side plate and the blade are joined by pressing the side plate on the blade in the direction of the rotational axis.

(B) In case of thermoplastic resin formation, there is the problem of weight gain due to the increase

of quantity of materials and poor ease of work. That is, forming a thermoplastic resin can cause a

surface subsidence, which leads to poor ease of work. As a thickness of a blade with poor ease of work it is substantially equal along the impeller height direction from the main plate to the side plate, in the case of wing type blade in which the thickness of the blade gradually increases from the inner impeller circumference in a plan view perpendicular to the rotational axis and also decreases towards the outer impeller circumference, in the vicinity of the center of the blade having a larger thickness, for example, the thickness increases at the upper edge of the tilted blade in a side view resulting in an increase in the amount of materials used, resulting weight gain and the appearance of a surface subsidence.

(C) Additionally, an inclination angle at the upper edge of the blade is increased at least toward the outer impeller circumference from the inner circumference so that the amount of incoming flow air in the joined piece of blade side plate and as a result it interferes with the air flow from the inner circumference of the blade blade impeller, causing noise or vibration that degrades the surrounding environment (later in this report called "degraded noise problem").

(D) In a turbo fan described in patent document 2, the joined piece of side plate side of the blade exit edge is displaced a predetermined amount in the opposite rotational direction from the attached piece of main plate side, which improves the homogenization of the wind speed distribution on the front face side of the heat exchanger disposed downstream of the impeller, but causes the air flow to concentrate on the side plate side at the blade outlet edge in the impeller output, which leads to a problem of degraded noise.

(E) Moving the joined piece of side plate side of the blade leading edge a predetermined amount in the rotational direction from the joined piece of main plate side prevents a separation around the joined piece of side plate side, but remains without change a gap in a region from the intermediate piece of the blade leading edge to the blade side, piece still attached to the plate side, so that there is room for noise reduction.

(F) In addition, the joined piece of side of blade side plate is tilted in the rational direction relative to the piece joined of side of main plate, and the surface of the main plate and the surface of blade pressure (surface of the opposite rotational direction) forms a pronounced angle of less than 90 degrees. This causes a flow of incoming air from the leading edge to drift to the side of the main plate, leaving a separation region at the leading edge of the blade on the side of the side plate.

(G) Additionally, moving the joined piece of side of the blade side plate on the sides of the leading and trailing edges in the reverse direction causes a region from the piece attached to the side of the blade side plate attached to the plate lateral to the piece attached to the side of the main plate tilts with respect to the side plate, which leads to difficulty of assembly, such as a turbo fan described in patent document 1.

(H) While, in a turbo fan described in patent document 3, the joined piece of side plate side moves on a piece from the blade leading edge to the exit edge in the rotational direction relative to the attached piece of main plate side, and the side plate side end on the leading edge side tilts in the rotational direction, which prevents the separation of an air inlet flow at the side end of the side plate and the piece attached on the side of the side plate, but it causes an inlet air flow from the leading edge to drift on the side of the main plate, leaving a separation region at the edge of the blade on the side of the side plate.

(I) In the case of a turbo fan formed by molding at least one blade and a side plate separately and joining them by welding or coupling to a unit, as the entire blade tilts in the rotational direction,

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the blade and the side plate are joined by pressing the blade in the direction of the rotational axis, which causes an effort to be exerted on the joined piece of the main plate side and prevents a force from being properly applied to the blade on the plate side lateral, which leads to difficulty of assembly.

JP 2008-2379 describes a centrifugal fan that includes a circular main plate and a circular side plate and a plurality of hollow blades provided in parallel between the main plate and the side plate at predetermined blade intervals in the circumferential direction. On the side plate side of the blade an auxiliary air intake port is provided to take air into a hollow area, while an auxiliary air intake port is provided on the negative pressure face side of the outer peripheral part of the blade.

The present invention has managed to solve the problems described above. An object of the present invention is to provide a turbo fan and an air conditioning apparatus provided therewith, which provides low noise emission, ease of assembly and good workability by suppressing a separation region at a blade leading edge, a side plate side end, and a trailing edge, while performance degradation is minimized even if resistance to air flow is added.

Means to solve the problems

(1) According to the present invention, a turbo fan is provided as specified in the claims.

(2) An air conditioning apparatus according to the present invention includes the mounted turbo fan, and a ventilation pressure loss unit provided on the side of an inlet opening of the turbo fan.

Advantages

(i) With this arrangement, a turbo fan according to the present invention provides a homogeneous wind speed distribution in the fan outlet opening. As a result, if a heat exchanger is provided downstream of the turbo fan, air flows vertically uniformly at least in the vicinity of the fan outlet opening, thereby suppressing a flow of air flowing over the surface without passing through of the heat exchanger due to a difference in wind speed as well as reducing a loss of pressure, resulting in a reduction in the level of operating noise.

(ii) Also, an air conditioning apparatus according to the present invention suppresses the separation of air at a blade leading edge of the turbo fan and provides low noise operation, even if a ventilation pressure loss unit is provided, such as a filter, in a turbo fan inlet opening.

Brief description of the drawings

[Figure 1] Figure 1 is a longitudinal sectional view showing an air conditioning apparatus according to embodiment 1 of the present invention.

[Figure 2] Figure 2 is a perspective view showing a turbo fan according to embodiment 2 of the present invention.

[Figure 3] Figure 3 is a plan view, partially in cross section, of a turbo fan shown in Figure 2, as seen from a fan inlet opening side.

[Figure 4] Figure 4 is a side view showing a section taken along the line X-X of Figure 3.

[Figure 5] Figure 5 is a side view showing a blade of a turbo fan shown in Figure 2.

[Figure 6] Figure 6 is a sectional view showing a section taken along the line L1-L1 of Figure 5.

[Figure 7] Figure 7 is a sectional view showing a section taken along the line L2-L2 of Figure 5.

[Figure 8] Figure 8 is a sectional view showing a section taken along line L3-L3 of Figure 5.

[Figure 9] Figure 9 is a sectional view showing a section taken along line L4-L4 of Figure 5.

[Figure 10] Figure 10 is a plan view showing a section taken along line L5-L5 of Figure 5.

[Figure 11] Figure 11 is a longitudinal sectional view showing a section taken along the line K1-K1 of Figure 3.

[Figure 12] Figure 12 is a longitudinal sectional view showing a section taken along the line K2-

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K2 of figure 3.

[Figure 13] Figure 13 is a diagram showing the relationship between an angle of inclination to the blade's leading edge and a noise level associated with the same volume of air.

[Figure 14] Figure 14 is a diagram showing the relationship between a circumferential angle of curvature and a noise level associated with the same volume of air.

[Figure 15] Figure 15 is a diagram showing the relationship between an angular difference of Ap2 output and a noise level associated with the same volume of air.

[Figure 16] Figure 16 is a diagram showing the relationship between an angle of curvature £ and a noise level associated with the same volume of air.

[Figure 17] Figure 17 is a diagram showing the relationship between an angular input difference Ap1 and a noise level associated with the same volume of air.

[Figure 18] Figure 18 is a perspective view showing a turbo fan according to embodiment 3 of the present invention.

[Figure 19] Figure 19 is a longitudinal sectional view of a blade of a turbo fan shown in Figure 18.

[Embodiment 1: air conditioner]

Figure 1 is a longitudinal sectional view showing an air conditioner according to embodiment 1 of the present invention. An air conditioning apparatus according to embodiment 1 of the present invention is equipped with a turbo fan according to embodiment 2 which will be described below, and is described below with reference to the accompanying drawings.

In Fig. 1, a type of air conditioner body embedded in the ceiling (later referred to herein as "air conditioner body") 10 is mounted on a ceiling 21 of a room 20 of such that it is embedded in a rectangular shaped hole formed in the ceiling 21. In other words, the air conditioning apparatus body is a box that has an opening formed in the lower part thereof and that has an upper plate 10a and a side plate 10b opposite the top plate 10a. The side plate 10b has a side plate opening (which communicates with a body inlet opening 10c) formed in the center thereof and has a bottom edge substantially flush with the roof 21, whereby an opening of the body of Air conditioner is also substantially flush with the roof 21.

Additionally, the decorative panel 11 in substantially rectangular form in a plan view is installed in the side plate 10b or the ceiling 20 while facing the room 20 to cover the lower end of the side plate 10b and the hole in rectangular form of the ceiling 21. The decorative panel 11 includes an inlet grille 11a, which is an air inlet opening for the air conditioner body 10, provided in the center thereof, a filter 12 for removing dust from the air that A panel exit opening 11b formed along each side of the decorative panel 11 has passed through the inlet grill 11a. Each panel outlet opening 11b is provided with a wind direction vane 13.

In addition, a turbo fan 1, a bell mouth 14 forming an inlet air passage for the turbo fan, a fan motor 15 for rotating and driving the turbo fan 1 and a heat exchanger are disposed within the body of the air conditioner 10 heat 16 to perform heat exchange of the room air attracted to the body of the apparatus (later referred to herein as "attracted air") respectively. The heat exchanger 16 is formed to have a substantial C shape in plan view, installed upright to surround the periphery of the turbo fan 1, and connected to an outdoor unit (not shown) through the piping system of Connection.

The body of the air conditioning apparatus 10 includes a body inlet opening 10c formed in the center thereof, and around the body inlet opening 10c a body outlet opening 10d is formed. The body inlet opening 10c communicates with the inlet grill 11a of the oriented panel 11, while the body outlet opening 10d communicates with the panel outlet opening 11b of the decorative panel 11.

In the air conditioner 10 according to this arrangement, when the turbo fan 1 rotates, the air in the room 20 is attracted to the turbo fan 1 after passing through the inlet grill 11a of the decorative panel 11, the dust-removing filter 12 , the body inlet opening 10c, and the bell mouth 14. Next, the air blows into the heat exchanger 16 where the air is subjected to heat exchange including heating or cooling and dehumidification, and is blown out of the panel outlet opening 11 b towards the room 20 through the body outlet opening 10d while being subjected to wind direction control by the wind direction vane 13. So the air in room 20 is air conditioning (later in this report it is referred to as "air conditioning").

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[Embodiment 2: turbo fan]

Figures 2 to 17 are views showing a turbo fan according to embodiment 2 of the present invention. Figure 2 is a perspective view. Figure 3 is a plan view, partially in cross section, of a turbo fan, as seen from a fan inlet opening side. Figure 4 is a side view showing a section taken along the line X-X of Figure 3, Figure 5 is a partial side view. Figures 6 to 9 are partial flat sectional views. Figure 10 is a partial plan view. Figures 11 and 12 with partial sectional views. Figures 13 to 17 are diagrams showing the relationship between a noise level and an angle of each section.

Figure 2 corresponds to a perspective view of Figure 1, as seen when looking up at the ceiling 21. Figure 4 and Figure 1 (Embodiment 1) are inverted views, where air is drawn from the upper side in the figure 4 and is blown out to the right and left directions in Figure 4. A top-to-bottom address in Figure 4 is called "height direction", while a left-to-right direction and a direction facing back is called "horizontal direction" for convenience. In Figure 1 and the other figures, the same reference numbers and symbols refer to the same components, and descriptions of the components are partially omitted.

Fig. 13 is a diagram showing the relationship between an angle of inclination to of the leading edge of the blade and a noise level associated with the same volume of air. Figure 14 is a diagram showing the relationship between a circumferential angle of curvature and a noise level associated with the same volume of air. Figure 15 is a diagram showing the relationship between an angular difference of Ap2 output and a noise level associated with the same volume of air. Figure 16 is a diagram showing the relationship between an angle of curvature £ at a leading edge of blade 4a3 and a noise level associated with the same volume of air in relation to the ratio of an airflow resistance no dust accumulation in a filter disposed on one side of the dust accumulation inlet. Figure 17 is a diagram showing the relationship between an angular input difference Ap1 and a noise level associated with the same volume of air, the angular input difference is an angular difference between an input angle of the leading edge of the leading edge. of blade and an entry angle at one end of the inner circumferential side of the blade leading edge at a height of a concave shaped bottom where a vertical warping line C12 becomes the maximum along the opposite rotational direction in an outer circumferential surface of blade.

In Figures 2 to 5, the turbo fan 1 is integrally formed from a main plate 2 of a revolution body (disk) having a substantially angular section, a side plate 3 of a circular ring having a substantially arc section circular arranged to be opposite the periphery of the main plate 2, and a plurality of blades 4 arranged to extend from the main plate 2 to the side plate 3. The main plate 2 includes an elevation 2a formed in the center (convex piece which it has a substantially angular formed section thereof), the elevation 2a is a fixed area to which a rotational shaft O of the fan motor 15 is secured. Consequently, a rotational axis is parallel to the height direction and perpendicular to the horizontal direction

In the circular ring-shaped side plate 3, a side plate opening formed in the center of it forms a fan inlet opening 1a. The peripheral piece (skirt having a substantially angular section formed) of the main plate 2 and the side plate 3 form wind guide walls, and a space defined by these components forms a fan outlet opening 1b. In other words, in Figure 1, as the peripheral edge section of the main plate 2 and the section of the side plate 3 are ascending towards the outer circumference, air flow is formed that rises (indicated by a given down arrow that the upper side is down in figures 2 to 12) and then moves horizontally towards the outer circumference.

(Blade arrangement)

In a plan view of the blade 4, the blade 4 is located further away from the rotational axis O as it approaches the blade leading edge from the blade leading edge 4a. The blade is connected at its end edge of the blade 4 near the side plate 3 to the side plate in a region (4ec4 ~ 4g1) near the trailing edge of blade 4e, and is located in the side plate opening that moves away of the side plate 3 in a region (4g1 ~ 4a3) near the leading edge of blade 4a. The blade 4 has a hollow structure having a cavity therein and an opening formed outside the impeller of the main plate 2 such that a wall thickness T (equal to the distance between the outer circumferential surface of the blade and the surface inner circumferential of the blade) in a horizontal section perpendicular to the rotational axis O of the blade 4 decreases from a position near the main plate 2 to a position near the side plate 3.

(Blade trailing edge)

The blade exit edge 4e of the blade 4 is located in a hypothetical cylinder defined by connecting the circumferential edges of the main plate 2 and the side plate 3, and has a wavy shape that has at least two inflection points in a hypothetical cylinder of this type. That is to say, an intersection of a horizontal warping line C1 and the leading edge of blade 4e represents, in relation to an intersection 4ec1 as a joined point of main board side in the height direction, an intersection 4ec2 which is a point of main plate side inflection that

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it has a curvature towards a rotational direction in a convex shape at a predetermined position on the side of the main plate 2 closer to the center of the fan outlet opening 1b, an intersection 4ec3 which is a turning point of side plate side which has a curvature towards the rotational direction of recoil in a concave shape on the side of the side plate 3 closer to the center of the fan outlet opening 1b, and an intersection 4ec4 which is a joined point of side plate side of the side plate 3. In other words, a line G connecting between the joined piece of the main plate side 4ec1 and the joined piece of the side plate side 4ec4 is erected in the vicinity of the main plate 2 and the side plate 3 for be parallel to the rotational axis O, while the blade leading edge on the side of the main plate 2 tilts in the rotational direction A relative to that of the side of the side plate 3 between the inflection point of the main plate side 4ec2 and the inflection point of the side plate side 4ec3 so that the blade leading edge 4e has a substantial S shape.

At this time, the blade exit edge 4e is located on a hypothetical cylinder defined by connecting the outer circumferential edges of the main plate 2 and the side plate 3, and a line G connecting a joined point on the side of the main plate 4ec1 and a point attached to the side plate side 4ec4 is orthogonal (orthogonal as a normal line) to the outer circumferential surface of the main plate 2 to be parallel to the rotational axis O.

Also, the trailing edge of blade 4e is parallel to the normal line of the side plate 3 in the vicinity of the side plate 3. Furthermore, between the point of curvature of the main plate side 4ec2, which is a location in a stub curved side of main plate which is the one that protrudes most in the rotational direction A, and the point of curvature of side plate side 4ec3, which is a location in a curved side piece of lateral plate that is the most protruding in the direction opposite the rotational direction A, the trailing edge of blade 4e protrudes more in the rotational direction A as it is closer to the main plate 2, to be inclined in a side view. As a result, the trailing edge of blade 4e has a substantial form of S.

Accordingly, on the outer circumferential surface of blade 4b, attracted air is divided by the point of curvature of the main plate side 4ec2 to the sides of the main plate 2 and the central area in the height direction of the outlet opening 1b , thereby preventing the air flow from concentrating on the side of the main plate 2. An inclined section 4e5 between the point of curvature of the main plate side 4ec2 and the point of curvature of the side plate 4ec3 exerts a force in the direction of the side plate 3, guiding the air flow. Additionally, a piece between the lateral plate side curvature point 4ec3 and the joined lateral plate side point 4ec4 guides, on the inner circumferential surface of the blade 4c thereof, the flow of air from a piece around the piece attached to the side plate side 4g at the leading edge of the side plate side end 4a1 of the blade 4 to the side of the side plate 3 in the fan outlet opening 1b.

(Shape in cross section of the blade)

The horizontal cross-sectional shape of the blade 4 will be described. Figures 6 to 10 are sectional views taken along the line L1-L1, the line L2-L2, the line L3-L3, the line L4-L4, and line L5-L5 of Figure 4, respectively. The rotational direction is indicated by the "arrow A".

In other words, Figure 6 is a sectional view taken along the line L1-L1 at the side end of main board 4d attached to the main board 2. Figure 7 is a cross-sectional view taken at along the line L2-L2 located on the side of the main board 2 from the center of the fan outlet opening 1b. Figure 8 is a cross-sectional view taken along the line L3-L3 located on the side of the side plate 3 from the center of the fan outlet opening 1b. Figure 9 is a cross-sectional view taken along the line L4-L4 that goes through the side plate 3 in the fan outlet opening 1b. Figure 10 is a cross-sectional view taken along line L5-L5 when the side plate 3 corresponding to a blade 4 is removed.

In section L1-L1 (figure 6), a central line of wall thickness (equal to the center between the inner and outer circumferential surfaces of the blade) in the section is indicated by the "horizontal warping line C1", and "the intersection of the horizontal warping line C1 and the blade leading edge 4a "and" the intersection of the horizontal warping line C1 and the leading edge of blade 4e "are indicated by" 4ac1 "and" 4ec1 ", respectively.

Also, in section L2-L2 (Figure 7), a center line of wall thickness in the section is indicated by the "horizontal warping line C2", and "the intersection of the horizontal warping line C2 and the edge of blade attack 4a "and" the intersection of the horizontal warping line C2 and the trailing edge of blade 4e "are indicated by" 4ac2 "and" 4ec2 ", respectively.

Similarly, in section L3-L3 (figure 8), "horizontal warping line C3" is indicated by "4ac3" and "4ec3". Also, in section L4-L4 (figure 9), the "horizontal warping line C3" is indicated by "4ac4" and "4ec4". To each figure reference numerals "4ac1" and "4ec1" are added to make clear a phase in the height direction.

In Figures 6 to 9, the blade 4 is a wing-like blade that gradually thickens toward the center of the blade from the leading edge of the inner circumference side of the blade 4a2, and gradually thins towards the leading edge of the blade 4e .

In a section L1-L1 shown in Figure 6, the blade 4 is tilted back against the rotational direction A and

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curved radially out. In a section L2-L2 shown in Figure 7, the side of the main plate 2 of the blade exit edge 4e curves in an oblique way backward in the rotational direction A. Additionally, in a section L3-L3 shown in Figure 8, the vane trailing edge 4e curves obliquely in the opposite direction to the rotational direction A against the joined area of the main board side 4ec1.

In section L4-L4 shown in figure 9, the joined point of side plate side 4ec4 and the joined point of side of main plate 4ec1 in section L1-L1 shown in figure 6 have the same phase in a view in plant as seen from the fan inlet opening 1a, and the inner circumference side end of the leading edge bends radially outward.

Additionally, in a plan view shown in Figure 10, the point of curvature of the main plate side 4ec2 and the point of curvature of the side plate side 4ec3 are arranged to form a predetermined angle and crossing the joined point of the side of main plate 4ec1 and the joined point of side plate side 4ec4.

In Fig. 6 (section L1-L1), the angle (acute angle) between a tangent line E1 to the horizontal warping line C1 at the intersection 4ec1 of the horizontal warping line C1 and the trailing edge of blade 4e, and a line of tangent F1 to a concentric circle with the rotational axis O and passing through the intersection 4ec1 is referred to as "exit angle p21".

In Figure 7 (L2-L21 section), the angle (acute angle) between a tangent line E2 to the horizontal warping line C2 at the intersection 4ec2 of the horizontal warping line C2 and the trailing edge of blade 4e, and a line of tangent F2 to a concentric circle with the rotational axis O and passing through the intersection 4ec2 is referred to as "exit angle p22". Similarly, "outlet angle p23" and "outlet angle p24" are defined in Figure 8 (section L3-L3) and Figure 9 (section L4-L4), respectively.

The blade 4 is formed so that these exit angles have the relationship "p23 <p21 = p24 <p22".

(Blade leading edge)

In Figures 2 and 3, the blade leading edge 4a in the blade 4 on the air inlet side has a shape defined by the side end of the side plate 4a1 and the inner circumferential side end 4a2 continuously formed with the leading edge 4a3 as a bending point. The side plate side end 4a1 collapses towards the fan inlet opening 1a as it approaches the "joined piece of side plate 4g (see Figure 4) where the blade 4 and the side plate 3" meet from the end of leading edge 4a3. In other words, the side plate side end 4a1 approaches the side plate 3 by tilting to approximate the normal line of the side plate 4.

In Figure 3, the intersection of the horizontal warping line C1 and the inner circumferential side end of the blade leading edge 4a2 is called "intersection 4ac1", the intersection of the horizontal warping line C1 and the trailing edge of Extreme blade 4e is called "intersection 4ec1", and a line that connects intersection 4ac1 and intersection 4ec1 is called "rope line D".

A longitudinal section perpendicular to the rope line D in the vicinity of the inner circumferential end of the blade leading edge 4a2 is called "section K1-K1", and the blade 4 in section K1-K1 is shown in Figure 11. A longitudinal section perpendicular to the rope line D at the end in a 4g1 rotational direction of the joined piece of side plate (equal to the border between a joined region and a region located in the side plate opening) is called "section K2-K2 ", and blade 4 in section K2-K2 is shown in Figure 12.

In Figures 11 and 12, central lines of vertical thickness (equal to the center line between the inner circumferential surface of the blade and the outer circumferential surface of the blade) in section K1-K1 and section K2-K2 are called "lines of vertical warping C12 ", while angles between the vertical warping line C12 and the rotational axis O at the blade leading edge 4a3 (section K1-K1) and on the joined piece of blade side plate 4g1 (section K2 -K2) are called "angle of curvature £ 1" and angle of curvature £ 2 ", respectively.

In Figures 2, 11 and 12, a separate region of the side plate 3, at an end edge of the blade near the side plate 3 (equal to the region located in the side plate opening), is curved to be located radially farther out in a position closer to the blade leading edge 4a in a plan view, and expands to be further away from the end edge in the curved region closer to the blade leading edge 4a in a side view.

In other words, the blade end side of the blade leading edge 4a1 and the inner circumferential side end of the leading edge 4a2 on the side of the side plate 3 curves radially outward so that the angle of curvature it becomes larger at a position closer to the inner impeller circumference (equal to a position closer to the blade leading edge 4a) with the end in the rotational direction 4g1 on the outer circumferential surface of the blade of the joined piece of plate lateral 4g is as a support point and the blade leading edge of blade 4a3 is as a power point.

Consequently, the curved region is formed to have a substantial triangle shape in a side view, causing an oblique "fold line B" to be created on the outer circumferential surface 4b of the blade 4 to

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extend towards the inner circumferential side end of the blade leading edge 4a2 of the blade leading edge from the end in the rotational direction 4g1 to the main plate 2.

Additionally, as shown in Figures 4 and 11, the blade thickness T gradually becomes larger so that the outer circumferential surface of blade 4b of the blade leading edge 4a on the side of the main plate 2 is radially curved. outwards, and at the same time the vertical warping line C12 bends radially outwards.

In section K2-K2 shown in Figure 12, the outer circumferential surface of blade 4b is substantially perpendicular to the outer circumferential surface of the main plate 2. Only the inner circumferential surface of blade 4c on the side of the side plate 3 is bends radially outward, and the blade 4 remains substantially erect with its thickness becoming smaller towards the side plate 3 from the main plate 2 (with increasing height), as a whole.

For the entry angles (311, (312, (313 and (314) shown in cross-sectional views of Figures 6 to 10, an entry angle p1 gradually becomes larger in a region from the leading edge of the leading edge of blade 4a3 to the side plate 3 to cause the entrance angle p14 at the blade leading edge 4a3 to be the smallest, so that p14 is smaller than p11, and p12 and p13 of middle pieces in the direction of height are greater than at least p11 and p14, respectively (p12> p11, p13> p14).

As described above, in a side view as seen from the inner circumference, the blade leading edge 4a is formed at least so that the outer circumferential surface of blade 4b on the sides of the blade side plate 4a1 and the main plate 2 is formed to have a convex shape in relation to the rotational direction A, while the inner circumferential surface of blade 4c is formed to be radially curved outward.

(Effects and advantages)

As shown in Figure 2, when rotated by the fan motor 15 in the rotational direction A, the turbo fan 1 having the above structure substantially blows the room air (attracted air), which has been attracted through radially outwardly. from the fan inlet opening 1a and passed through the blade 4, through the fan outlet opening 1b, providing the following effects and advantages.

(i) A homogeneous distribution of wind speed is provided in the fan outlet opening 1b. As a result, if the heat exchanger 16 is provided downstream of the turbo fan 1, the air flows uniformly to the heat exchanger, at least in the vicinity of the fan outlet opening 1b, thereby suppressing a secondary air flow that it flows over the surface without passing through the heat exchanger 16 due to a difference in wind speed as well as reducing a loss of pressure, resulting in a reduction in the level of operating noise (see Figure 1).

Also, the trailing edge of blade 4e remains upright in the vicinity of the main plate 2 and the side plate 3, which makes it possible to precisely apply a force parallel to the rotational axis O at the time of welding work during assembly, in comparison with conventional turbo fans where the trailing edge 4e tilts in relation to the main plate 2 and the side plate 3, thereby preventing defective welding caused by the rear clearance of the blade 4.

(ii) "Tilt angle of exit edge a2" or an angle of inclination between an inclined section 4e5, which is located between the point of curvature of the main plate side 4ec2 and the point of curvature of the side plate side 4ec3, and a line G parallel to the rotational axis O is established from 10 to 30 degrees. This prevents flow from concentrating on the outer circumferential surface of blade 4b on the side of the side plate 3 in the fan outlet opening 1b. Also, this prevents a flow from the side end of the leading edge side plate 4a1 from being concentrated on the inner circumferential surface of the blade 4c on the side of the side plate 3, thereby reducing a noise level as shown in the relationship between the inclination angle of the trailing edge a and the noise level associated with the same wind volume (see Figure 13).

(iii) In Figure 10, a circumferential curvature angle and between a line connecting the impeller rotational axis with the main plate side curvature point 4ec2 and a line connecting the rotational axis with the side curvature point 4ec3 side plate is set from 5 to 15 degrees. When the heat exchanger 16 is disposed downstream of the fan outlet opening 1b, this arrangement allows the air flow to be dispersed even at the moment when the blade outlet edge 4e approaches the heat exchanger 16 due to the 1 turbo fan running and the resistance to air flow increases locally. As the effects of the angle of inclination a of leading edge, this arrangement also prevents a flow from being concentrated on the side of the side plate 3 of the outer circumferential surface of blade 4b in the fan outlet opening 1b, as well as prevents that a flow from the leading edge of the side plate 4a1 be concentrated on the side of the side plate 3 of the inner circumferential surface of the blade 4c, thereby reducing a noise level as shown in the relationship between the angle of circumferential curvature and and the noise level associated with the same wind volume (see Figure 14).

(iv) In each cross-sectional view of the blade in a plane perpendicular to the rotational axis, "angular difference

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Ap2 "which is a difference between the exit angle p22 at the point of curvature of the main board side 4ec2 and the exit angle p23 at the point of curvature of the side plate side 4ec3 is set at 20 to 35 degrees. Accordingly , in the air conditioner 10, the blade outlet edge is formed to have a substantial S shape with concave and convex curvature, so that even if a distance between the heat exchanger 16 (pressure loss body of ventilation having a substantial form of C in a plan view) disposed on the fan outlet side and the fan outlet opening 1b changes in the circumferential direction, the blade outlet edge 4e regulates an air flow due to to the substantial form of S.

Accordingly, the present invention provides a small change in the wind speed distribution, thereby reducing a noise level, unlike conventional apparatus in which an air flow is concentrated in the fan outlet opening 1b in the side of the main plate 2, in a region where the fan 1 is close to the heat exchanger 16, which causes a greater separation on the side of the side plate 3 and a significant increase in the noise level (see Figure 15 which shows the relationship between an angular difference of Ap2 output and a noise level associated with the same volume of air).

(v) At the blade leading edge 4a, the attracted air is gently introduced without hitting the outer circumferential surface 4b and producing a turbulent flow at the inner circumferential side end of the blade leading edge 4a2 on the plate side side 2 and on the side plate side induction piece 4b1 (side end side of the leading edge 4a1 curves radially outwardly) on the outer circumferential surface of blade 4b, since, in a side view as viewed from the center (rotational axis O), the outer circumferential surface 4b on the side of the side plate 3 and the main plate 2 is curved to have a concave shape in relation to the rotational direction A.

This arrangement increases a volume of air blown at the same fan rotation speed, which leads to a lower fan rotation speed than to obtain the volume of air blown necessary for heat exchange of the air conditioning apparatus 10, which gives as result in reduced operating noise levels as well as reduced motor power consumption due to a rotational drive of the fan with a reduced drive torque.

(vi) The outer circumferential surface of blade 4b of the blade leading edge 4a on the side of the main plate 2 is formed to bend radially outward, which allows an air flow to pass through the surface of the plate main 2 from the elevation 2a so that it is directed towards the center of the blade height, preventing the air flow from concentrating on the side of the main plate 2, together with an air flow from the inner circumferential side end of blade leading edge 4a2.

Also, the air flow can be smoothly introduced to the outer circumferential surface of blade 4b without hitting blade 4, thereby preventing turbulence.

Consequently, a homogeneous distribution of wind speed can be achieved as well as reduced noise levels by preventing a separation on the side plate side and a concentration on the main plate side, while conventional devices suffer from the concentration distribution of wind speed on the side of main board at the fan outlet opening.

(vii) The inner circumferential surface of the blade 4c of the leading edge of the blade 4a on the side of the side plate 3 is formed to lean radially outward and curl, which allows air attracted on the inner circumferential surface 4c to flow smoothly to along the curved surface tilted towards the trailing edge of blade 4e. This prevents the separation of air flow from near the side plate 3 which is found in conventional turbo fans, thereby reducing noise levels.

(viii) With the end in the rotational direction 4g1 on the circumferential surface of blade 4b on the joined piece of side plate 4g as a support point and the blade leading edge of blade 4a3 as a power point, the "bend angle £ (equal to an angle between the vertical warping line C12 and a line parallel to the rotational axis O) becomes larger towards the inner circumference side of the impeller in a longitudinal cross section perpendicular to the rope D in a horizontal section in the Blade main plate side end 4d In other words, the leading edge side plate edge of leading edge 4a1 and the inner circumferential side end of leading edge 4a2 on the side of the side plate 3 curves radially towards out towards the rotational direction surface 4b of the blade 4 (towards the inner circumferential side end of the blade leading edge 4a2 from the inner circumferential side end 4g1 d the joined piece of side plate) to create a fold line B (oblique line, see figure 2) that goes to the side of the main plate 2.

This arrangement reduces the difference between an incoming flow at the inner circumferential side end of the blade leading edge 4a2 on the side of the side plate 3 and an incoming flow at the side end of the side edge of the leading edge 4a1, in comparison with a conventional curvature with an initial point on the horizontal line perpendicular to the rotational axis O.

(ix) The inner circumferential side end of the leading edge 4a2, and the side end of the leading edge side plate 4a1 are connectively formed to a substantially triangular shape with the leading leading edge 4a3 as an apex, which homogenizes a vertical vortex that occurs at the end of the circumferential side

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inside blade leading edge 4a2 and the side end of the leading edge side plate 4a1 around the blade leading edge 4a3, causing it to be stabilized by an air flow is guided on the inner circumferential surface of the blade 4c. Therefore, even if the filter 12 (ventilation pressure loss body disposed on the side of the fan inlet opening 1a) has dust accumulated thereon and the resistance to air flow is increased, flow separation hardly occurs of air, thereby suppressing deterioration of noise levels that is low.

(x) Figure 16 is a diagram showing the relationship between an angle of curvature £ and the "noise level ratio in relation to the resistance to air flow" associated with the same volume of air. That is, it shows the "noise level ratio in relation to resistance to air flow" which is the ratio of a value for the filter that does not have accumulated dust with that of the filter that has accumulated dust. As shown in Figure 16, if £ 1 is within a range between 25 and 45 degrees, a low noise turbo fan and a low noise air conditioner can be obtained which hardly suffers airflow separation regardless of a change in resistance to air flow in the fan inlet opening 1a.

(xi) Additionally, as shown in Figure 12, the blade 4 has its thickness T decreasing towards the side plate 3 in the height direction of the fan from the main plate 2 and has a hollow structure having an opening 2b in the outer impeller of main plate 2, which contributes to a reduction in weight. This arrangement reduces the starting torque exerted on the lift 2a at a start of a fan motor as well as suppresses distortion, which leads to an improvement in the durability of the turbo fan 1.

(xii) In addition, in the blade 4, the longitudinal cross section K1-K1 shown in Figure 6 (longitudinal cross section containing the end in the rotational direction 4g1 in the joined piece of side plate of the blade 4 perpendicular to the rope D in a horizontal cross section at the side end of the blade main plate 4d) and a predetermined region is formed towards the trailing edge of the downstream blade 4e to remain substantially erect parallel to the rotational axis O in relation to the main plate 2 Consequently, when the main plate 2 is pressed against the blade 4 parallel to the rotational axis O in order to weld the blade 4 and the side plate 2 in a body, the "concentration of stresses at the side end can be mitigated. of blade main plate 4d "that a conventional blade will be found that tilts with respect to the main plate 2, thereby preventing buckling of blade 4 so that assembly is facilitated relax as well as improve reliability.

(xiii) As at an angle of entry p1 in each cross-sectional view of the blade 4 taken along a plane perpendicular to the rotational axis O, the angle of entry (314 at the blade leading edge of blade 4a3 is the smaller at the leading edge 4a Additionally, the entry angle p1 in a piece near the center in the impeller height direction at the inner circumferential end of the blade leading edge 4a2, is formed radially inwardly to be larger that the entry angle p11 on the main board side and the entry angle p14 on the advanced end blade, that is, has a ratio of p1> p11> p14.

Additionally, the entry angle p1 is designed to gradually become larger towards the joined piece of side plate 4g from the blade leading edge 4a3 on the side blade side end blade 4a1, thereby reducing "an angle incident 8 "which is the angular difference between" inlet flow J "and the inlet angle p1 in a horizontal section perpendicular to the rotational axis O at the inner circumferential side end of the blade leading edge 4a2, as well as allowing air attracted be gently attracted with less separation, which leads to a reduction in noise levels.

(xiv) From the blade leading edge 4a3 to the joined piece of side plate 4g at the side edge of the blade leading edge 4a1, the drawn air is introduced radially with a slope towards the inlet opening of fan 1a, and also introduced radially by gradually increasing the inlet angle p, to mitigate the separation on the side of the side plate 3 as well as to homogenize the wind speed distribution in the fan outlet opening 1b.

(xv) An angular difference between the entry angle p14 (see Figures 8 and 11) at the blade leading edge 4a3 and the entry angle p12 at the inner circumferential side end of leading edge 4a2 (see Figures 7 and 11) in a position of height in a concave shaped lower part in which the vertical warping line C12 is directed mainly in the opposite rotational direction on the outer circumferential surface of blade 4b is established as "angular difference Ap1 ".

With this arrangement, as shown in Figure 17, although an excessively greater angular difference Ap1 causes a separation on the inner circumferential surface of blade 4c on the side of the main board 2 as well as increased noise levels, the angular difference Ap1 from 10 to 20 degrees causes a reduction in noise levels.

(xvi) By the way, a blade leading edge 4e formed to a curved shape as a substantial S shape and a blade leading edge 4a formed to bend radially outwardly provide noise reduction effects individually, as compared to the blade conventional.

Additionally, the combination of these shapes allows the attracted air to be gently attracted along the leading edge of the entire blade 4a, causing a rectified air flow to be drawn to the trailing edge.

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of blade 4e. This facilitates the flow of the attracted air along the substantially S-shaped surface of the blade with less turbulence, in addition to homogenizing the wind speed distribution and reducing noise levels due to synergistic effect.

As described above, a turbo fan according to the present invention is a reliable and durable low noise turbo fan.

An air conditioner equipped with this type of turbo fan ensures a comfortable use environment free from annoying noise as well as trouble free use for a long time. Thus, an air conditioner of low cost and high quality can be provided.

[Embodiment 3: turbo fan]

Figures 18 and 19 show a turbo fan according to embodiment 3 of the present invention. Figure 18 is a perspective view, while Figure 19 is a partial cross-sectional view (to be precise, a longitudinal sectional view of the blade 4 in a plane perpendicular to the rope D at the side end of the main plate of blade 4b). The same symbols and reference numerals in Figures 18 and 19 as those of embodiment 2 (Figures 2 to 12) refer to the same components, and repeated descriptions of the same components are partially omitted.

In Fig. 18, an end side of the leading edge side plate 4a1 which is an edge of the blade 4 near the curved side plate 3 to be placed radially further outwardly as it approaches the inner circumferential side end of the edge of attack 4a2 in a plan view, in a region that moves away from the side plate 3 (equal to a region located in the side plate opening), and the curved region expands to move away from that end as it approaches the end of inner circumferential side of leading edge 4a2 in a side view.

In other words, the turbo fan 30 has a fold line B gradually oriented in the direction of the main plate 2, which is formed at the side end of the leading edge side plate 4a1 curved radially out of the blade 4 and in the outer circumferential surface of blade 4b at the inner circumferential side end of leading edge 4a2 on the side of the side plate 3 to be directed towards the inner circumferential side end of leading edge 4a2 of the blade 4 from the end in the direction rotational 4g1 on the outer circumferential surface of blade 4b on the joined piece of side plate 4g.

Additionally, a rectangular concave groove 5 is formed on the inner circumferential surface of blade 4c in the curved region to be substantially perpendicular to the fold line B and extends obliquely outwardly to the side of the main plate 2 from the side of the side plate 3 in relation to the rotational axis O.

In Figure 19, the concave groove 5 becomes more shallow as it is closer to the side end of the leading edge side plate 4a1.

In other words, the blade 4 is formed of a component that constitutes the outer circumferential surface of the blade and a component that constitutes the inner circumferential surface of the blade, and has a dual structure that has a gap formed therein. These two components are joined together at the side end of the leading edge side plate 4a1, and the distance between them becomes larger at a position further away from the side end side of the leading edge of the leading edge 4a1.

The lower part of the groove 5a of the concave groove 5 is formed with the component that constitutes the outer circumferential surface of the blade, whereby the depth of the concave groove 5 corresponds to the distance between the inner circumferential surface of the component constituting the outer circumferential surface of blade and the inner circumferential surface of the component constituting the inner circumferential surface of blade.

When driven by a fan motor in the rotational direction A, the turbo fan 30 having the above structure attracts air through the fan inlet opening 1a and substantially blows the air attracted in the rotational direction through the fan outlet opening 1b, after passing through the blade 4.

When air is drawn to the blade 4, the air flows smoothly over and along the outer circumferential surface of the blade 4c to the blade exit edge without turbulence, since the side end of the leading edge side plate 4a1 curves in the direction radially out. Also, the concave groove 5 extends obliquely to expand towards the side of the main plate 2 from the side of the side plate 3 in relation to the rotational axis O, thereby allowing the lower part groove 5a to rectify the air flow and suppress turbulence, which leads to further reduction of noise levels.

The bottom of the groove 5a of the concave groove 5 is formed to extend along the outer circumferential surface of the blade 4b, to make the thickness of the blade 4 smaller. In case of a turbo fan formed of thermoplastic resin, this arrangement prevents Surface sinking due to smaller wall thickness even in a curved piece that tends to have a larger wall thickness, resulting in better formation reliability.

In particular, the turbo fan 30, if installed in an air conditioner 10 (see Figure 1) that has a ventilation pressure loss body such as a filter disposed in the fan inlet opening 1a thereof, prevents The separation of air flow and keeps low noise levels even if dust gradually accumulates on the filter and results in increased resistance to air flow.

5 Industrial applicability

A turbo fan according to the present invention can be widely used for domestic and industrial use due to its low noise and high manufacturing reliability. Additionally, such a turbo fan can be widely used for home and industrial air conditioners.

Claims (15)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 1. A turbo fan comprising: a disc-shaped main plate (2) having an elevation (2a) that is a fixed piece to which a rotational shaft (O) of an engine is secured; an annular side plate (3) having a side plate opening formed in the center thereof and forming a wind guide wall together with the main plate (2); Y a plurality of blades (4) mounted to extend between the main plate (2) and the side plate (3); in a plan view of the blade (4), each blade (4) is positioned further away from the rotational tree (O), when it comes from a blade leading edge (4a) to a blade leading edge (4e); wherein an outer circumferential surface (4b) and an inner circumferential surface (4c) of the blade (4) at the blade leading edge (4a) have a central region in the height direction substantially parallel to the rotational shaft (O), characterized by that the blade has a skirt area near the main plate (2) that is located radially further out of the main plate (2) when approaching the main plate (2) at the blade leading edge (4a), and another skirt area near the side plate (3) that is located radially further out of the side plate (3) when approaching the side plate (3) at the blade leading edge (4a), and The outer circumferential surface of the blade (4b) of the blade leading edge (4a) on the side of the main plate (2) is curved outwardly from the main plate (2). 2. The turbo fan of claim 1, wherein the blade (4) is connected at its end edge near the side plate (3) to the side plate (3) in a region near the blade exit edge (4e ), and is located in the side plate opening away from the side plate (3), in a region near the blade leading edge (4a), and the blade leading edge (4e) of the blade (4) has a wavy shape that has at least two inflection points located in a hypothetical cylinder that connects outer circumferential edges of the main plate (2) and the side plate (3) and has a curved side piece of main plate that protrudes in a rotational direction in a region closer to the main plate (2) and a curved side piece of side plate protruding in an opposite rotational direction in a region closer to the side plate (3). 3. The turbo fan of claim 1, wherein, in a region located in the side plate opening, an end edge of the blade (4) near the side plate (3) bends to be located radially further outwardly in accordance with the extreme edge approaches the blade leading edge (4a) in a plan view, and expands to be positioned further away from the end edge as its curved region approaches the blade leading edge (4a) in a side view. 4. The turbo fan of any one of claims 1 to 3, wherein a line connecting a piece where the blade leading edge (4e) joins the main plate (2) and a piece where the outlet edge of blade (4e) joins the side plate (3) is parallel to the rotational shaft (O). 5. The turbo fan of any one of claims 1 to 4, wherein the blade (4) has a hollow structure with a decreasing shape, which has a gap formed therein where the distance between the outer circumferential surface of the blade (4b ) and the inner circumferential surface of the blade (4c) is gradually smaller towards the side plate (3) from the main plate (2). 6. The turbo fan of any one of claims 1 to 5, wherein a central line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) is parallel to the rotational shaft (O) in a region where the blade (4) joins the side plate (3). 7. The turbo fan of claim 2 or 4, wherein, in a side view of one end of the blade exit edge (4e), an inclined line connecting a maximum projection (4ec2) in the rotational direction in the curved piece side of main plate and a maximum projection (4ec3) in the opposite direction on the curved piece of side plate inclines from 10 to 30 degrees with a vertical line connecting a connection part with the main plate (2) and a connection part with the side plate (3). 8. The turbo fan of claim 2 or 4, wherein, an angle of circumferential curvature (y), which is an angle in a plan view, formed by a line connecting a center of the rotational shaft (O) and an intersection of a horizontal warping line showing a central line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) and an outer circumferential edge of the main plate (2) in a plan view of the connecting part with the main plate (2), and a line connecting the center of the rotational shaft (O) and the intersection of the horizontal warping line showing the center line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) and a circumferential edge of the side plate (3) in a plan view of the connection part with the side plate (3) is 5 to 15 degrees. 5 10 fifteen twenty 25 30 35 40 9. The turbo fan of claim 2 or 4, wherein an angular difference (Ap2) between a lateral outlet angle of main plate, in a plan view of the curved side piece of main plate, formed between a tangent to a line of horizontal warping showing a central line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) at one end of the blade exit edge (4e) and a tangent at the end of the exit edge of blade (4e) to a circle that passes through the end of the blade exit edge (4e) having its center in the center of the rotational shaft (O), and a lateral plate side exit angle, in a plan view of the lateral curved piece of lateral plate, between a tangent to the horizontal warping line showing the central line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) at the end d the blade exit edge (4e) and a tangent at the end of the blade exit edge (4e) to the circle passing through the end of the blade exit edge (4e) having its center in the center of the tree Rotational (O), is 20 to 35 degrees. 10. The turbo fan of claim 3, wherein, in a side view, an angle of curvature (e) that is an angle formed between a tangent at one end of the blade leading edge (4a) to the vertical warping line which shows the center line between the outer circumferential surface of the blade (4b) and the inner circumferential surface of the blade (4c) and the rotational shaft (O) is 25 to 45 degrees. 11. The turbo fan of any one of claims 1 to 10, wherein, at one end of the blade leading edge (4a) in a plan view, a side entry angle of blade side plate which is an angle of entry at a position closer to the side plate (3), an average blade entry angle that is an angle of entry in the middle of the side plate (3) and the main plate (2) in a height direction, and a lateral entry angle of blade main plate which is an entry angle at a position closer to the main plate (2) have a ratio of "the average blade entry angle> the side entry angle of main plate of blade> the side entry angle of blade side plate ". 12. The turbo fan of claim 11, wherein at the end of the blade leading edge (4a) in a plan view, an angular difference (Ap1) between an average inner circumferential entry angle of blade which is an angle of entrance at one end of the inner circumferential side in the middle of the side plate (3) and the main plate (2) in a height direction and a side entry angle of the blade side plate which is an angle of entry at one end Closer to the side plate (3) is 10 to 20 degrees. 13. The turbo fan of claim 3, wherein a concave groove (5) is formed on the inner circumferential surface of the blade in the curved region of the blade (4) to extend to one end near the side plate (3), is defines a fold line (B) at a boundary of the curved region and the inner circumferential surface of the blade except the curved region, and the concave groove (5) is substantially parallel to the fold line (B); where, optionally, the concave groove (5) has a rectangular section and is gradually more shallow towards an end near the side plate (3). 14. An air conditioning apparatus, wherein the turbo fan of any one of claims 1 to 13 is mounted, and a ventilation pressure loss unit (12) is provided at an air inlet opening of the turbo fan. 15. An air conditioning apparatus, wherein the turbo fan of any one of claims 1 to 13 is mounted, and a ventilation pressure loss unit (12) is provided in an air outlet opening of the turbo fan.