JP2932975B2 - Axial blower, air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower widely used in air conditioners for home use and industrial use, and more particularly to an axial blower capable of minimizing aerodynamic noise. is there.

[0002]

2. Description of the Related Art Blowers are widely used in air conditioners, ventilation fans and the like, and it is very important in society to reduce the noise generated by the impeller as much as possible. Among the conventional techniques, a method for reducing noise is disclosed in
As disclosed in Japanese Patent Application Publication No. 000, the parameters for determining the three-dimensional shape of the impeller are clarified and the shape is optimized. FIG. 97 is a perspective view showing a conventional impeller disclosed in Japanese Patent Publication No. 2-2000. In the figure, 1 is the blade of the impeller, 1a is the tip of the blade, 1b is the leading edge of the blade, 1c is the trailing edge of the blade, 1d is the outer peripheral portion of the blade, 2 is the boss for attaching the blade, 3 is the rotating shaft, and 4 is the rotating shaft. The direction of rotation.

FIG. 98 is a projection view when the impeller is projected on a plane orthogonal to the rotation axis 3, wherein 1 ′ is a blade in the plane projection view, 1 a ′ is a tip of the blade in the plane projection view,
1b 'is a leading edge of the blade in the plan view, 1c' is a trailing edge of the blade in the plan view, and 1d 'is a blade outer periphery in the plan view. Further, FIG. 100 shows a case where the boss chord line center point Pb ′ in FIG.
Of the chord line center point PR at an arbitrary radius R with respect to the trajectory Pb'-PR'-Pt 'in the radial direction up to the plane OX.
The radial distribution of the chord line center point PR, which is rotationally projected on the surface with the radius R, and the cross section at the same position of the blade 1 are shown.
FIG. 100 is a developed view obtained by cutting the blade 1 with a cylindrical surface having a radius R when the blade surface is formed with the chord battle center point PR as a relative origin, and expanding the cross section into a two-dimensional plane. 5 is a sled line, 5a is a blade negative pressure surface, 5b is a blade pressure surface, and 6 is a rotation axis parallel line.

In this impeller, the three-dimensional curved surface shape of the blade 1 is concretely defined by clarifying various factors constituting the blade 1. On a projection plane when the impeller is projected on a plane orthogonal to the rotation axis in FIG. 98, a chord line center point in a cross section when the boss portion of the blade is cut by a cylindrical surface having a radius Rb is Pb ′, With the rotation axis as the origin O and a coordinate system with the straight line connecting the point O and the point Pb 'as the X axis, the chord line center point when the blade is cut by a cylindrical surface with a radius R as PR', As a straight line Pb ′,
The angle between the straight line Pb′-O and the X axis is δθ (δθ:
(Rotational advance angle), the radial distribution of δθ is δ
θ = δθt × (R−Rb) / (Rt−Rb) (Rt: radius of blade tip, Rb: radius of blade boss, δθt: straight line P
R'-O and the X axis), δθt = 40 ° to 50 °, and in FIG. 98, the cross section of the impeller cut along a cylindrical surface of radius R centered on the rotation axis. When the distance between the chord line center point PR and a plane SC passing through the chord line center point Pb in a cross section when the boss portion of the blade is cut by a cylindrical surface having a radius Rb and orthogonal to the rotation axis is Ls. In the coordinate system in which the airflow suction side is set to the positive direction, the chord line center point PR is always located in the positive direction with respect to the SC plane, and δz = tan ⁻¹ (Ls / (R−Rb))
Δz the value of δz that can be expressed by: (δz suction direction anteversion)
= 12.5 ゜ -32.5 ゜,

In FIG. 100, a blade is cut along a cylindrical surface having a radius R, and a cross-section thereof is developed into a two-dimensional plane. When the central angle for forming the shape is θ (θ: warp angle), the radial distribution of θ is θ
= (Θt−θb) × (R−Rb) / (Rt−Rb) + θ
b (θt: deflection angle at the blade tip, θb: deflection angle at the blade boss), θt = 20 ° to 30 °, θb = 27 ° to 37 °, θt <θb, and mounting of the blade The position is parallel to the chord line 1b-1c and the rotation axis 3 and the blade leading edge 1
If the angle formed by the straight line 6 passing through b and the stagger angle ξ is defined as ξ, the radial distribution of ξ is expressed as ξ = (ξt−ξb) × (R−
Rb) / (Rt−Rb) + ξb (ξt: stagger angle at the blade tip, ξb: stagger angle at the blade boss), {t = 62} to 72 ゜, {b = 53 to 63 ゜, ξt>
100, L is a chord length, and the size of the blade is limited by the chord ratio T / L using the circumferential distance T between the blades shown in FIG. T / L = 1 to 1.1 at each radius point. By making the impeller having such a three-dimensional curved surface shape, the development of the boundary layer on the blade surface is suppressed and the state of the discharge vortex is changed. Had become.

[0006]

Although the conventional axial blower has the characteristic of low noise as described above, the vicinity of the operating point where the air volume is large and the wind pressure is not so small as shown in FIG. In the vicinity of the edge boss portion, there is a problem that the sucked air collides against the negative pressure surface side of the blade, causing turbulence in the flow on the negative pressure surface of the blade, causing pressure fluctuation and increasing noise. Also, when the pressure loss of the suction flow is large, that is, when dust or the like adheres to the suction port side and suction becomes difficult, a flow separation phenomenon occurs near the leading edge of the blade on the blade negative pressure surface, causing a large turbulence. Since the included flow flows on the blade negative pressure surface, a large pressure fluctuation occurs, and there is a problem that noise increases.

Further, the blades of the conventional axial blower are not
There was a tendency for stress concentration to escape by increasing the thickness of the plate near the boss of the leading edge of the blade. Therefore, when the leading edge of the blade is locally thickened, the flow collides with the thicker leading edge boss portion of the blade, and the resulting turbulence disturbs the flow on the blade surface, causing pressure fluctuation. The noise tended to increase, resulting in an increase in noise. The present invention has been made in order to solve the above-mentioned problems, and it is a high-performance, low-noise, and high-strength device that prevents a collision of a suction flow at a blade leading edge boss portion and also achieves a high static pressure. The objective is to obtain a sufficient axial flow fan. Still another object of the present invention is to obtain a low-noise air conditioner.

[0008]

According to a first aspect of the present invention, there is provided an axial flow blower mounted on a rotating boss portion, the leading edge of the blade facing in the rotating direction, and the trailing edge of the blade facing in the opposite direction to the rotating direction. And a blade having a periphery formed by a blade outer peripheral portion opposed to the boss portion, and one side along the boss portion of the blade front edge portion, and another along the outer periphery of the boss portion adjacent to the blade front edge portion. And a plate-like member having a thickness substantially equal to the thickness of the blade, the side being disposed, and being attached to at least one of the blade leading edge portion and the boss portion and integrally formed with the blade. .

In the axial flow blower according to the second aspect of the present invention, the center of rotation is defined as the origin O, and a radius O-1bs 'with respect to a point 1bs' on the leading edge of the blade at an arbitrary radius is angle β in the rotation direction.
The intersection point with the outer periphery of the boss portion when rotated is 1bb ', and the plate-like member has a substantially triangular shape passing through the 1bs' and 1bb'. In the axial blower according to the third aspect of the present invention, the center of rotation is defined as the origin O, and the radius O- of an arbitrary radius relative to the point 1bs' on the leading edge of the blade is obtained.
1bb 'is defined as 1bb', where the intersection with the outer periphery of the boss portion when 1bs 'is rotated by an angle β in the rotation direction is 1bb'.
When placed between s ′ and 1bb ′, the angle β is 1
It is selected from 0 to 40 degrees.

In the axial blower according to a fourth aspect of the present invention, the plate-like member may be formed such that the center of rotation is the origin O, the point 1bs' on the leading edge of the blade at an arbitrary radius, and the radius of the outer periphery of the blade is Rt. When one side is disposed between the boss portion and 1bs 'of the blade front edge, the radius O-1bs' is selected to be 40 to 75% of the blade outer radius Rt. Further, in the axial blower according to the fifth invention, the plate-shaped member is attached to the blade front edge portion in close contact with the blade in the rotational direction.

An axial flow blower according to a sixth aspect of the present invention is provided with a blade front edge facing the rotating direction, a blade trailing edge facing the rotating direction, and a boss mounted on the rotating boss. And a side along the outer periphery of the boss portion adjacent to the blade front edge portion, and one side along the boss portion of the blade front edge portion, and the other side disposed along the outer periphery of the boss portion adjacent to the blade front edge portion. Along with at least one of the blade leading edge portion and the boss portion and integrally formed with the blade, a plate-like member having a thickness substantially equal to the blade thickness, and an axis O of rotation as an origin O, Point 1 on leading edge of blade at arbitrary radius
bs', and a radius O-1bs' between the bs' and the origin O.
And a plate-like member passing through 1bs 'and 1bb' when the intersection with the outer periphery of the boss portion is rotated by an angle β in the rotation direction, and the angle β is selected from 10 to 40 degrees. And the radius O-1bs' is 40 to 7 of the blade outer radius Rt.
5% was selected.

An axial blower according to a seventh aspect of the present invention is provided with a blade front edge facing the rotating direction, a blade trailing edge facing the rotating direction, and a boss mounted on the rotating boss. And a radius O-1bs 'of an arbitrary radius and a point 1bs' on the leading edge of the blade at an arbitrary radius and an angle β rotation in the rotation direction. The point of intersection with the outer periphery of the boss at the time of
b ′, a blade shape in which a portion near the boss portion of the blade front edge is extended in the rotation direction in a shape passing through 1bs ′ and 1bb ′, and the angle β is selected from 10 to 40 degrees. It is. The axial blower according to the eighth invention has a radius O
-1bs' is selected as 40 to 75% of the blade outer radius Rt. The axial blower according to the ninth invention is
It has a plurality of blades whose angle β is changed with respect to the individual blades. Also, the axial blower according to the tenth aspect of the present invention,
Each of the blades has a plurality of blades whose radius O-1bs' is changed.

[0013] In the axial blower according to the eleventh aspect, the blade shape in which a portion of the blade front edge portion is extended from the boss portion in the rotation direction may be formed such that tangent lines at 1bs 'and 1bb' are concave with respect to the rotation direction. It is formed so as to be a knotted blade front edge portion with a curved line. In the axial blower according to the twelfth aspect, the connecting portion between the leading edge of the blade and the boss portion may be concave in the rotating direction in which the radius of the blade is 15 to 35% of the outer radius of the blade. The blade shape is formed so as to be connected by a curve and to be the leading edge of the blade.

An axial flow blower according to a thirteenth aspect of the present invention is the axial flow blower, wherein the blade is mounted and rotated, the blade front edge facing in the rotation direction, the blade rear edge facing in the direction opposite to the rotation direction, and A blade having a circumference formed by a blade outer peripheral portion facing the boss portion, and an arbitrary point 1bs ′ on the blade front edge portion.
A leading edge of the blade is formed so as to linearly connect a point 1bb 'on the side surface of the boss located in the rotational direction from a tangent line between the point 1bb' and the point 1bs' with respect to the tip of the leading edge of the blade. Is the origin O, the radius O-1bs' is 40 to 75% of the blade outer radius Rt.

[0015] Further, axial-flow fan according to a fourteenth aspect of the present invention, the axial center of the rotation as the origin O, connecting the origin O and 1BaO 'point on the front blades of the blade root edge straight 1BaO'-O
Is rotated by an angle δαb between 20 ° and 50 ° in the rotation direction about the origin O, the point 1b of the boss radius Rb
The shape between b ′ and the point 1bs ′ on the leading edge of the blade having a radius Rs of 40 to 70% of the radius of the outer peripheral portion of the blade is defined as the boss radius Rb of the blade with respect to the leading edge of the blade. The radius Rc between the boss portion radius Rb and the radius Rs existing between the point 1bb 'on the blade front edge and the boss portion radius Rb when rotated in the rotation direction by the angle δαb from the point 1ba' on the edge. Point of
A straight line 1bc'- O connecting 1bc ' and the origin O and a straight line 1b
δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs), and a point 1b on the leading edge of the blade so as to be continuous with the blade.
The blade front edge of the portion closer to the boss portion than s' is extended in the rotation direction to form a blade shape.

In the blower according to the fifteenth aspect of the present invention, a straight line connecting the origin O with the origin O being the center of the rotation axis and the point 1baO 'on the leading edge of the blade at the boss radius Rb of the base blade 1O'. When the point at which 1baO′-O is rotated by an angle δαb between 20 ° and 50 ° in the rotation direction about the origin O is defined as a blade leading edge boss portion extension end point 1bb ′, the blade has an arbitrary radius R. In a developed view obtained by cutting the cylindrical surface of FIG. 1 and expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is changed to the point 1bb while the blade 10 and the warp angle θ and the stagger angle 同一 are the same. At this time, the chord length LbO at the boss radius Rb of the blade 1O and the chord length Lb from the point 1bb to the blade trailing edge 1cb, and the difference between them is ΔLb ,
Assuming the chord length Ls at the point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the radius of the outer peripheral portion of the blade, the boss portion radius R
The radial distribution of the chord length L from b to the point 1 bs on the leading edge of the blade is given by L = △ Lb / (Rs−Rb) ² × (R−Rs) ² + Ls (Rb ≦ R ≦ Rs) A blade shape is formed.

An axial blower according to a sixteenth aspect of the present invention is characterized in that a blade of the axial blower is cut by a cylindrical surface having an arbitrary radius R, and a cross-section thereof is developed into a two-dimensional plane. When the shape of the warp line in the cross section is an arc shape and the center angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (R−
Rb) / (Rt−Rb) + θb (θt: slew angle at the outer periphery of the blade, θb: slew angle at the radius Rb of the blade boss portion), and θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt
<Θb, and in the developed view, when an angle between a chord line of the blade and a straight line that is parallel to the rotation axis and passes through the leading edge of the blade is denoted by ξ (ξ: stagger angle), the radial direction of ξ The distribution is expressed as ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery 部, ξ
b: stagger angle at boss radius Rb), Δt
= 55 ゜ -70 ゜, ξb = 40 ゜ -65 ゜, ξt> ξb, and the chord ratio defined by the chord length L and the ratio of T to the circumferential distance (pitch) between the blades. The value of T / L is
T / L = 1.1 to 2.0 at each radial point, and in the projection of the axial blower projected on a plane perpendicular to the rotation axis, when cut at the cylindrical surface of the boss radius Rb of the blade. In the coordinate system in which the chord line center point in the cross section is Pb ′, the rotation axis is the origin O, and a straight line connecting the point O and the point Pb ′ is the X axis, the blade is a cylindrical surface having an arbitrary radius R. The center point of the chord line at the time of cutting is PR ', and the straight line P
When the angle between R′-O and the X axis is δθ (δθ: advancing angle in the rotation direction), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt−Rb) (Rt: Blade outer radius, Rb: Blade boss radius, δθ
t: the angle between the straight line Pt'-O and the X axis), δθt
Is set to 25 to 40 °, a blade shape is first formed, and a straight line 1ba′-O connecting the point 1ba ′ on the blade front edge portion of the root of the blade at this time and the origin O is rotated around the origin O. To 2
The point 1bb ′ of the boss radius Rb when rotated by an angle δαb between 0 and 50 ° and the radius of the outer periphery of the blade 40 to 70
% From the point 1ba 'on the leading edge of the blade, which is the boss radius Rb of the blade, with respect to the leading edge of the blade, with respect to the leading edge of the blade. The boss radius R existing between points 1bb 'on the blade leading edge at the boss radius Rb when rotated in the rotation direction by the angle δαb
b~ the radial distribution of .delta..alpha showing points 1bc radius Rc an angle between -O and linear 1Ba'-O 'linearly 1bc connecting the origin O' of between radius Rs δα = (δαb / (Rb- Rs) ² ) × (R-Rs) ² (Rb ≦ R ≦ Rs), and a blade shape is formed by extending the blade front edge portion closer to the boss portion from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. It is.

An axial blower according to a seventeenth aspect of the present invention is a development in which the blade of the axial blower is cut by a cylindrical surface having an arbitrary radius R, and the cross section is developed on a two-dimensional plane. Assuming that the shape of the warp line in the cross section is an arc shape and the central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (R−
Rb) / (Rt−Rb) + θb (θt: slew angle at the outer periphery of the blade, θb: slew angle at the radius Rb of the blade boss portion), and θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt
<Θb, and in the developed view, when an angle between a chord line of the blade and a straight line that is parallel to the rotation axis and passes through the leading edge of the blade is denoted by ξ (ξ: stagger angle), the radial direction of ξ The distribution is expressed as ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery 部, ξ
b: stagger angle at boss radius Rb), Δt
= 55 ゜ -70 ゜, ξb = 40 ゜ -65 ゜, ξt> ξb, and the projection of the axial flow blower on a plane perpendicular to the rotation axis shows the cylindrical surface having the boss radius Rb of the blade. The chord line center point in the cross section when cut is Pb
O ′, the rotation axis is the origin O, and the point O and Pb
In a coordinate system in which the straight line connecting the point O ′ is the X axis, the chord line center point when the blade is cut by a cylindrical surface having an arbitrary radius R is PR
Assuming that the angle between the straight line PRO′-O and the X axis is δθ (δθ: advancing angle in the rotation direction) as O ′, the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt− Rb) (Rt: radius of outer periphery of blade, Rb: radius of blade boss, δθ
t: the angle between the straight line PtO'-O and the X axis), δθ
t is set to 25 to 40 °, and the value of the chord ratio T / LO defined by the chord length LO and the ratio of T to the circumferential distance (pitch) between the blades is defined as T / LO at each radial point. / LO = 1.
First, a blade shape 1O 'is formed, and a straight line 1ba connecting the origin O with the point 1baO' on the front edge of the blade at the boss radius Rb of the blade 1O 'in the projection view.
When the point when O′-O is rotated by an angle δαb between 20 and 50 ° around the origin O in the rotation direction is defined as a blade leading edge boss portion extension end point 1bb ′, the blade has an arbitrary radius R. In the developed view obtained by cutting the cylindrical surface of FIG. 1 and expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is set to the same value as the blade 10 and the warp angle θ and the stagger angle 同一. The blade chord length LbO at the boss radius Rb of the blade 1O at this time and the chord length Lb from the point 1bb to the blade trailing edge 1cb, and the difference between the chord length Lb and the blade outer periphery radius Assuming the chord length Ls at the point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the radial direction of the chord length L from the boss radius Rb to the point 1bs on the leading edge of the blade distribution L = △ Lb / (Rs- Rb) 2 × (R-Rs) 2 + Ls (Rb ≦ R ≦ R Given by), it is obtained by forming a blade shape. An air conditioner according to an eighteenth aspect uses the above-described axial blower.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 An embodiment will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of an axial blower according to the present invention.
For example, it has a three-blade shape, and its operation is mainly described for one blade 1, but the same applies to other blades. In the drawing, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached, 3 is a rotation axis of the blade 1, 4 is an arrow indicating a rotation direction, 1b is a blade front edge, and 1d is a blade front edge. An outer peripheral portion of the blade, 1c is a trailing edge portion of the blade, and 7 is a triangular flat plate attached to a boss portion of the leading edge portion 1b of the blade. FIG. 2 is a plan view of FIG.

FIG. 3 shows the blade 1 on a plane orthogonal to the rotation axis 3.
FIG. In the drawing, the same reference numerals as those in FIG. 1 indicate the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the figure, a flat plate 7 'having substantially the same thickness as the blade and having a substantially triangular shape is adhered to one side 7b' substantially along the circumference of the boss portion 2 and the other side 7c 'to the boss portion of the blade front edge portion 1b'. It is extrapolated so as to be integral with the blade from the rotation direction to form a blade shape. FIG. 4 is an enlarged view in which a YY cross section obtained by cutting the vicinity of the triangular flat plate 7 ′ and the blade front edge 1b ′ of FIG. In the figure, reference numeral 1 denotes a blade of an axial blower, 7 denotes a triangular flat plate extrapolated to a boss portion of a blade front edge 1b, 7
c is an adhesive surface between the triangular flat plate 7 and the blade leading edge 1b;
a shows the suction side end of the triangular flat plate 7 which is continuous with the blade front edge 1b.

By forming as described above, at the time of high-voltage loss, the triangular flat plate 7 shown in FIG.
Of the flow from the pressure surface 9 to the suction surface 8 at one side 7a connected to the leading edge 1b of the blade, the flow is directed along the blade surface and the suction flow 12 The air is sent to the outside while being guided by 10. Thus, as a problem in the conventional axial blower, as shown in FIG. 101, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced. FIG. 6 shows the relationship between the flow coefficient φ and the pressure coefficient 流量 and the specific noise Ks [dB (A)] of the conventional axial flow fan and the axial flow fan according to the first embodiment of the present invention. It is a characteristic diagram.

Here, the flow coefficient φ, the pressure coefficient ψ, and the specific noise Ks will be described. The flow coefficient φ is expressed as follows, and is a dimensionless number. ^{φ = Q / (π 2/} 4 · D 3 · (1-ν 2) · N) Q: air volume [m ³ / min] D: the blade outer peripheral part radius [m] [nu: Boss ratio (boss radius / feather N: Number of rotations [rpm] The pressure coefficient ψ is a dimensionless number of the ratio between the dynamic pressure corresponding to the blade outer peripheral speed u and the pressure rise P. ψ = 7200 Ps / (ρ (πDN) ² ) Ps: Static pressure [Pa] D: Blade outer radius [m] N: Rotational speed [rpm] ρ: Air density [Kg / m ³ ] On the other hand, specific noise Ks is It is defined as: Ks = SPL-10 Log (Q · Ps ^2.5 ) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m ³ / min] Ps: Static pressure [mmAq]

In the figure, black circles and black squares show the characteristics and the minimum specific noise of the conventional axial flow fan, and x and □ show the characteristics and the minimum specific noise of the axial flow fan in one embodiment of the present invention. As can be seen from this characteristic diagram, the operating region where the blades are not stalled extends to the low air volume side and higher static pressure is achieved as a whole as compared with the conventional art. On the other hand, the specific noise Ks can be reduced by 1 [dB (A)] at the maximum, and the noise is low.

This axial flow blower has a boss mounted on a blade and rotating, a blade front edge facing the rotating direction, a blade rear edge facing the direction opposite to the rotating direction, and a blade outer periphery facing the boss. In the projected view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade composed of a periphery from a portion, a flat plate having a thickness substantially the same as the blade thickness on the blade front edge is substantially one side. Along the circumference of the boss, the other side is integrally formed with the blade so as to be extrapolated from the rotation direction so that the other side is close to the boss near the blade front edge, so dust accumulates at the suction port When a high pressure loss occurs, for example, when the flow wraps around from the pressure surface to the suction surface on one side connected to the leading edge of the triangular flat plate, the flow goes along the blade surface and the suction flow Sent outside by being guided by the vertical vortex By being, Nakuse flow disturbances 11 on the blade suction surface 8 due to separation of the suction flow 12 near the blade leading edge 1b at the time of the high pressure loss, it is possible to reduce noise.

Embodiment 2 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 7 is a perspective view showing an embodiment of the axial blower according to the present invention.
For example, it has a three-blade shape, and its operation is mainly described for one blade 1, but the same applies to other blades. In the drawing, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached, 3 is a rotation axis of the blade 1, 4 is an arrow indicating a rotation direction, 1b is a blade front edge, and 1d is a blade front edge. An outer peripheral portion of the blade, 1c is a trailing edge portion of the blade, and 7 is a triangular flat plate attached to a boss portion of the leading edge portion 1b of the blade. FIG. 8 is a plan view of FIG.

FIG. 9 shows the blade 1 on a plane orthogonal to the rotation axis 3.
FIG. In the drawing, the same reference numerals as those in FIG. 8 indicate the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the figure, the rotation axis is defined as the origin O,
In a coordinate system using a straight line connecting a point and an arbitrary point 1bs' on the blade leading edge 1b 'as an X axis, a boss portion when the straight line O-1bs' is rotated β around the origin O in the rotation direction. A flat plate 7 'having substantially the same thickness as that of the blade and having a substantially triangular shape is passed through the intersection 1bb' with the side surface and the point 1bs'.
b 'is made substantially along the circumference of the boss portion 2', and the other side 7c 'is brought into close contact with the boss portion of the blade front edge portion 1b'. The blade shape is formed by bonding or welding with a material.

FIG. 10 is a cross-sectional view taken along the line YY of FIG.
It is the enlarged view which expanded the cross section in the two-dimensional plane. In the figure, 1 'is a blade of the axial blower, 7' is a triangular flat plate extrapolated near the boss of the blade front edge 1b, and 7c 'is an adhesion surface between the triangular flat plate 7' and the blade front edge 1b '. , 7a 'indicate the blade leading edge 1b' and the triangular flat plate suction side end. FIG. 11 shows an example of a method of attaching the triangular flat plate 7 to the blade leading edge 1b. Reference numeral 14 denotes an insertion direction of the triangular plate, 15 denotes a three-dimensionally movable mounting jig, 1 denotes a blade, 2 denotes a boss, and 3 denotes a rotation axis. The mounting method of the triangular flat plate 7 is as follows. First, the jig 15 is inserted into the rotating shaft, and the height and angle of the blade front edge 1b to which the triangular flat plate 7 is mounted are adjusted, and then the triangular flat plate 7 is brought into close contact with the blade front edge 1b. The adhesive is applied to the flat portion of the portion 7b which is brought into close contact with the recess of the portion 7c and the side surface of the boss portion,
The jig 15 is attached by moving it in the insertion direction 14.

By forming the blade shape as described above, at the time of high pressure loss, as shown in FIG. 12, which shows a cross section taken along line X--X in FIG. Due to the stable vertical vortex 10 generated by the flow of the flow from the flow to the suction surface 8, the flow follows the blade surface, and the suction flow 12 is blown to the outside while being guided by the vertical vortex 10. Thus, as a problem in the conventional axial blower, as shown in FIG. 102, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced. In addition, the existing axial blower can be easily improved.

Here, a point 1bs on the blade leading edge 1b through which one vertex of the triangular plate 7 passes and the straight line O-1bs
Is rotated about the origin O, and the intersection 1b with the side surface of the boss 2
If the rotation angle β for obtaining b is too large or too small, the blades will be disturbed conversely, and the noise will be deteriorated. Therefore, there is an optimum range of the position of the point 1bs on the blade leading edge 1b and the rotation angle β. FIG. 13 shows that when the rotation angle β is constant, for example, when the angle is about 20 to 30 degrees, the position of the point 1bs on the blade leading edge 1b is determined by the ratio of the radius Rs at the point 1bs to the radius Rt of the blade outer peripheral portion. The effect on the water was determined experimentally. At this time, the specific noise Ks
Varies with the operating point, and the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. Here, the specific noise Ks is defined as the following equation. Ks = SPL-10 Log (Q · Ps ^2.5 ) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m ³ / min] Ps: Static pressure [mmAq] As shown in the figure, the radius Rs at the point 1bs on the blade front edge 1b is 0.4 of the blade outer radius Rt. When the value is between 0.75 and 0.75 times, the value of the minimum specific noise Ksmin is small and the noise is low. Also, in the figure, Rs / Rt = 0 (on the Y axis) indicates the value of the conventional axial flow fan with no flat plate attached,
It can be seen that the noise is at most 1 [dB (A)] lower than the conventional value.

FIG. 14 shows a ratio Rs /
The effect of the rotation angle β in FIG. 9 on noise characteristics when Rt = constant, for example, when 0.6 to 0.7, is obtained experimentally. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimum is graphed as the minimum specific noise Ksmin. As shown in the figure, the rotation angle β when rotating in the fan rotation direction around a straight line O-1bs connecting the point 1bs on the blade leading edge 1b and the origin O around the origin O is between 10 ° and 40 °. , The value of the minimum specific noise Ksmin is small and the noise is low.
Also, the value of about -10 ° around the figure shows the value of the conventional axial blower without the flat plate attached, but compared to the conventional value.
It can be seen that the maximum noise is 1 [dB (A)].

FIG. 15 shows the effect of the ratio Rs / Rt of the radius Rs at the position of 1 bs and the radius Rt of the outer peripheral portion of the blade and the effect of the rotation angle β on the noise characteristics. The results of graphing the values at points are shown. From FIG. 15, if 0.4 ≦ Rs / Rt ≦ 0.75 and 10 ° ≦ β ≦ 40 °, the minimum specific noise Ksmin is sufficiently small and the noise is low.

This axial flow blower has a boss mounted with blades and rotating, a leading edge of the blade facing the rotating direction, a trailing edge of the blade facing the direction opposite to the rotating direction, and a blade facing the boss. In a projected view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose circumference is formed from the outer peripheral portion, the thickness at the blade front edge is substantially the same as the blade thickness, and substantially triangular In a coordinate system in which one side is along the circumference of the boss portion and the rotation axis is the origin O, and the straight line connecting the point O and the point 1bs' on the leading edge of the blade at an arbitrary radius is the X axis, When O-1bs 'is rotated by an angle β in the rotation direction around the origin O, the intersection with the boss portion of radius Rb is 1bb' as a vertex, and the angle β is 10 ° ~
40 °, and the other side is 40 to 7 of the blade outer radius Rt.
5% of the blade front edge is formed so as to pass through the point 1bs' on the blade front edge, closely contacted with the boss portion of the blade front edge, and integrally formed with the blade so as to be extrapolated from the rotation direction.
At the time of high pressure loss, the vertical vortex generated by the flow of the flow from the pressure surface to the suction surface at one side 7a connected to the blade leading edge 1b of the triangular flat plate 7 causes the flow along the blade surface, and the suction flow Of the flow on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of a high pressure loss
Noise can be eliminated and noise can be reduced.

Embodiment 3 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 16 is a perspective view showing one embodiment of the axial flow blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge.

FIG. 17 is a plan view of FIG.
FIG. 18 is a projection view in which the blade 1 is projected on a plane orthogonal to the rotation axis 3. In the figure, the same reference numerals as those in FIG. 17 indicate the same components. 1 'is the blade in the projection, 1b'
Is the leading edge of the blade in the projection, 1c 'is the trailing edge of the blade in the projection, and 1d' is the outer periphery of the blade in the projection. In the figure, in a coordinate system in which a rotation axis is an origin O and a straight line connecting the point O and an arbitrary point 1bs' on the blade leading edge 1b 'is an X axis, a straight line O-1bs' is centered on the origin O. 1bb'-1 passing through the point of intersection 1bb 'with the side surface of the boss when rotated by an angle β in the rotation direction.
bs 'is the blade leading edge 1b' so that the blade leading edge 1
A blade shape is formed such that a portion of b ′ near the boss portion 2 is extended in the rotation direction of the axial blower.

By forming as described above, at the time of high pressure loss, 1bs'- which is a part of the blade leading edge portion 1b 'of FIG.
In FIG. 19 which is an XX section of 1bb ′,
Due to the stable vertical vortex 10 generated by the flow of the flow from the pressure surface 9 to the suction surface 8 of s-1bb, the flow is on the blade surface, and the suction flow 12 is blown to the outside while being guided by the vertical vortex 10. Is done. Thus, as a problem in the conventional axial blower, as shown in FIG. 102, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced.

Unlike the case where the blade shape is formed by attaching a separate part as in the second embodiment, the blade is manufactured by integral molding, so that the flow is disturbed by the concave portion at the joint or the convex portion due to the adhesive. Can be prevented and noise can be reduced. Here, the position of the point 1bs when extending the portion 1bs'-1bb 'of the blade front edge portion 1b from the boss portion 2 in the rotation direction and the straight line O-1bs are rotated about the origin O, and the boss portion 2 is rotated. If the rotation angle β when determining the intersection 1bb with the side surface is too large or too small, the blades will be disturbed conversely, and the noise will be deteriorated. Therefore, there is an optimum range of the position of the point 1bs on the blade leading edge 1b and the rotation angle β. FIG. 20 shows the position of the point 1bs on the leading edge 1b of the blade when the rotation angle β is constant and the effect on the noise characteristics is experimentally obtained by the ratio of the radius Rs at the point 1bs to the radius Rt of the outer peripheral portion of the blade. It is a thing.
At this time, since the specific noise Ks changes depending on the operating point,
The value at the operating point where the specific noise Ks is minimum is defined as the minimum specific noise Ks.
Graphed as min. Here, the specific noise Ks is defined as the following equation. Ks = SPL-10 Log (Q · Ps ^2.5 ) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m ³ / min] Ps: Static pressure [mmAq]

As shown in the figure, the point 1 on the blade leading edge 1b
The radius Rs at the position of bs is 0.4 of the blade outer radius Rt.
When the value is between 0.75 and 0.75 times, the value of the minimum specific noise Ksmin is small and the noise is low. Also, Rs / Rt = 0 in FIG.
(On the Y-axis) shows the value of the conventional axial blower without a flat plate attached. It can be seen that the noise is up to 2 [dB (A)] lower than the conventional value.

FIG. 21 shows the ratio Rs / indicating the position of the point 1bs.
The effect of the rotation angle β in FIG. 18 on the noise characteristics when Rt = constant was determined experimentally. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimum is graphed as the minimum specific noise Ksmin. As shown in the figure, the rotation angle β when rotating in the fan rotation direction about a straight line O-1bs connecting the point 1bs on the blade leading edge 1b and the origin O is the center of the origin O.
When it is between 0 ° and 40 °, the value of the minimum specific noise Ksmin is small and the noise is low. The value around -10 ° in the figure indicates the value of the conventional axial blower without the flat plate attached, but the noise is up to 2 [dB (A)] lower than the conventional value. I understand.

FIG. 22 experimentally examines the effects of the ratio Rs / Rt of the radius Rs at the position of 1 bs and the radius Rt of the outer peripheral portion of the blade and the rotation angle β on the noise characteristics. The results of graphing the values at points are shown. As shown in FIG. 22, when 0.4 ≦ Rs / Rt ≦ 0.75 and 10 ° ≦ β ≦ 40 °, the minimum specific noise Ksmin is sufficiently small and the noise is low.

This axial flow blower has a boss mounted with a blade and rotating, a leading edge of the blade facing the rotating direction, a trailing edge of the blade facing the direction opposite to the rotating direction, and a blade outer periphery facing the boss. In the projection view of projecting the axial blower on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference constituted by a portion, the rotation axis O and the blade outer peripheral radius on the blade front edge portion are 40 to 75. A straight line O-1bs 'connecting the point 1bs' which is a radius of 10% in the rotational direction around the origin O is 10 to 40 [deg.].
And an intersection 1bb 'between the straight line O-1bs' and the boss part side surface, which is the boss part radius, and the above 1b
s 'is connected by a straight line to form a blade shape in which the portion of the blade front edge portion near the boss is extended in the rotation direction, so that X is a part of the blade front edge portion 1b' when high pressure loss occurs. In the -X cross section, the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow to the outside while being guided by the vertical vortex. In addition, the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced.

Embodiment 4 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 23 is a perspective view showing an embodiment of an axial blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge.

FIG. 24 is a projection view in which the blade 1 is projected on a plane orthogonal to the rotation axis 3. In the figure, the same reference numerals as those in FIG. 1I 'is the blade in the projection, 1bI' is the leading edge of the blade in the projection, 1cI '
Denotes a trailing edge of the blade in the projection, and 1I ′ denotes an outer periphery of the blade in the projection. The subscripts II and III indicate the same ones of the other blades. In the figure, the rotation axis is the origin O, and the point O and the blade outer peripheral portion radius Rt that is different for each blade are 40 to 7.
In a coordinate system using a straight line connecting the point 1bs 'on the blade leading edge 1b' at a radius of 5% as the X axis, a straight line O-1b
A straight line 1bb'-1bs' passing through the point 1bs' and an intersection 1bb 'with the side surface of the boss when the s' is rotated by an angle β in the rotation direction about the origin O is the blade leading edge 1b'. The blade shape is such that the portion of the blade front edge 1b 'of each blade near the boss 2 is extended in the rotation direction of the axial blower. By forming in this way, at the time of high pressure loss,
1bs'-1b which is a part of the blade leading edge 1b 'of FIG.
In FIG. 25 which is an AA cross section of b ′, the 1bs-
Due to the stable vertical vortex 10 generated by the flow of 1bb from the pressure surface 9 to the suction surface 8, the flow flows along the blade surface and the suction flow 12 is blown to the outside while being guided by the vertical vortex 10. . Accordingly, as a problem in the conventional axial blower, as shown in FIG. 101, the suction flow 12 near the blade leading edge 1b at the time of high pressure loss
The turbulence of the flow 11 on the blade negative pressure surface 8 due to the separation of the blades can be eliminated, and the noise can be reduced.

The leading edge 1bI ', 1bI of each blade
Since the portions are different from the boss portions of I ′ and 1bIII ′, FIG.
, The number of blades Z and the number of rotations N indicated by a solid line in the prior art.
The rotation sound determined by [rpm] and the peak sound due to a sound that is a positive multiple of this generation frequency (NZ / 60 [Hz]) disappear as shown by the broken line, and the sound due to the specific frequency can be reduced.
As a result, abnormal sounds that are problematic in products can be avoided.

This axial flow blower has a boss mounted on the blade and rotating, a leading edge of the blade facing in the rotating direction, a trailing edge of the blade facing in the direction opposite to the rotating direction, and an outer periphery of the blade facing the boss. In the projection view of projecting the axial blower on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference constituted by a portion, the rotation axis O and the blade outer peripheral radius on the blade front edge portion are 40 to 75. A straight line O-1bs 'connecting the point 1bs' which is a radius of 10% to 40.degree.
Between the straight line O-1bs' and the boss portion side surface, which is the boss portion radius, is changed for each blade in the range, thereby forming a blade shape. At the time of damage, 1bs 'which is a part of the blade leading edge 1b'
Due to the stable vertical vortex 10 generated by the flow of -1bb 'from the pressure surface 9 to the suction surface 8, the flow flows along the blade surface, and the suction flow 12 is blown to the outside while being guided by the vertical vortex 10. By doing so, the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced. In addition, since the portion of each blade is different from that of the boss at the blade front edge, the rotation noise determined by the number of blades Z and the rotation speed N [rpm] in the conventional axial flow blower and the frequency of generation thereof (NZ / 60 [Hz]) The peak sound due to a sound that is a positive multiple of is eliminated, and the sound due to the specific frequency can be reduced. As a result, abnormal sounds that are problematic in products can be avoided.

Embodiment 5 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 27 is a perspective view showing an embodiment of an axial blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 28 is a front view of FIG.

FIG. 29 is a projection view in which the blade 1 is projected on a plane orthogonal to the rotation axis 3. In the figure, the same components as those in FIG. 28 indicate the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the projected view, a straight line O-1b 'is obtained by rotating a straight line O-1bs' connecting the rotation axis O and an arbitrary point 1bs' on the leading edge of the blade around the origin O in the rotation direction.
The blade shape is formed such that a tangent at an intersection 1bb 'between the s' and the boss portion side surface, which is the boss portion radius, and the point 1bs' is a knotted blade front edge with an arbitrary curve that becomes concave in the rotation direction. doing.

By forming in this way, at the time of high-pressure loss, as shown in FIG. 30 showing a cross section taken along line XX of FIG. Stable longitudinal vortex 1 generated by the flow wrap around 8
0, the flow is on the blade surface and the suction flow 1
2 is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, as shown in FIG. 102, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced. FIG. 32 shows the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks [dB] between the conventional axial fan and the axial fan according to the fifth embodiment of the present invention.
(A)] is a characteristic diagram obtained experimentally. In the figure, black circles and black squares show the characteristics and minimum specific noise of the conventional axial fan, and x and □ show the characteristics and minimum specific noise of the axial fan in one embodiment of the present invention. As can be seen from this characteristic diagram, the operating region extends to the low air volume side and higher static pressure is achieved as a whole as compared with the related art. On the other hand, the specific noise Ks is 2.5 [dB] at the maximum.
(A)] and low noise.

This axial flow blower has a boss portion to which a blade is attached and which rotates, a leading edge portion of the blade facing in the rotating direction, a trailing edge portion of the blade facing in the direction opposite to the rotating direction, and an outer periphery of the blade facing the boss portion. In the projection view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference formed from a portion, the rotation axis O and an arbitrary point 1b on the blade front edge are shown.
When the straight line O-1bs' connecting the s' is rotated in the rotation direction around the origin O, the intersection 1bb 'between the straight line O-1bs' and the boss part side surface which is the boss part radius and the point 1bs' Since the blade shape is formed so that the tangent line becomes the knotted blade front edge with an arbitrary curve that becomes concave with respect to the rotation direction, the blade near the boss portion of the blade front edge at high pressure loss The vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow is blown to the outside while being guided by the vertical vortex. The disturbance of the flow on the blade negative pressure surface due to the separation of the suction flow near the blade front edge 1b at the time can be eliminated, and the noise can be reduced.

Embodiment 6 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 33 is a perspective view showing one embodiment of the axial flow blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 34 is a front view of FIG.

FIG. 35 is a projection view in which the blade 1 is projected on a plane orthogonal to the rotation axis 3. In the figure, the same reference numerals as those in FIG. 34 denote the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the figure, in a coordinate system in which a rotation axis is an origin O and a straight line connecting the point O and an arbitrary point 1bs' on the blade leading edge 1b 'is an X axis, a straight line O-1bs' is centered on the origin O. The tangent at the point of intersection 1bb 'with the side surface of the boss when rotated β in the rotational direction and the tangent at the point 1bs' is formed as a knotting blade leading edge 1b' with an arbitrary curve that is concave with respect to the rotational direction. A tied blade shape is formed.

By forming as described above, at the time of high-pressure loss, 1bs'- which is a part of the blade leading edge portion 1b 'in FIG.
1bb ′ in FIG. 36, which is an XX cross section of 1bb ′.
Due to the stable vertical vortex 10 generated by the flow of the -1bb from the pressure surface 9 to the suction surface 8, the flow is blown to the outside while the suction flow 12 is guided by the vertical vortex 10 along the blade surface. You. Thereby, as a problem in the conventional axial blower, as shown in FIG.
Suction flow 1 near blade leading edge 1b at high pressure loss
2. Disturbing the flow on the blade negative pressure surface 8 due to the separation of
Noise can be reduced.

Here, when extending the portion 1bs'-1bb 'of the blade front edge portion 1b from the boss portion 2 in the rotation direction, point 1
bs and the straight line O-1bs are rotated about the origin O, and if the rotation angle β when determining the intersection 1bb with the side surface of the boss portion 2 is too large or too small, the blade is disturbed conversely. It will make noise worse. Accordingly, the position of the point 1bs on the blade leading edge 1b and the rotation angle β
There is an optimal range of FIG. 37 shows the position of the point 1bs on the blade leading edge 1b when the rotation angle β = constant by the ratio of the radius Rs at the point 1bs to the blade outer radius Rt.
The effect on noise characteristics was determined experimentally. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimized is set to the minimum specific noise Ksmin.
As a graph. Here, the specific noise Ks is defined as the following equation. Ks = SPL-10 Log (Q · Ps ^2.5 ) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m ³ / min]

Ps: Static pressure [mmAq] As shown in the figure, when the radius Rs at the point 1bs on the blade leading edge 1b is between 0.4 and 0.75 times the blade outer radius Rt. , The value of the minimum specific noise Ksmin is small and the noise is low. In the figure, Rs / Rt = 0 (on the Y axis) indicates the value of the conventional axial blower. As a result, it can be seen that the maximum noise is 2 [dB (A)] lower than the conventional value. FIG. 38 shows experimentally obtained effects of the rotation angle β in FIG. 35 on noise characteristics when the ratio Rs / Rt indicating the position of the point 1bs is constant. At this time, the specific noise K
Since s varies depending on the operating point, the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin.

As shown in the figure, the point 1 on the blade leading edge 1b
The rotation angle β when rotating the straight line O-1bs connecting bs and the origin O in the fan rotation direction around the origin O is 10 ° to
When it is between 40 °, the value of the minimum specific noise Ksmin is small and the noise is low. The value around -10 ° in the figure is
The values of the conventional axial blower are shown. It can be seen that the axial blower according to the present invention has a maximum noise of 2 [dB (A)] lower than the conventional one. FIG. 39 experimentally examines the effect of the ratio Rs / Rt of the radius Rs at the position of the point 1bs on the leading edge of the blade to the radius Rt of the blade outer periphery and the rotation angle β on noise characteristics.
The result of having graphed the value at the operating point where the specific noise Ks is minimized is shown. From FIG. 39, 0.4 ≦ Rs / Rt ≦ 0.75 and 1
If 0 ° ≦ β ≦ 40 °, the minimum specific noise Ksmin is sufficiently small and the noise is low.

This axial flow blower has a boss portion to which a blade is attached and which rotates, a leading edge portion of the blade facing in the rotating direction, a trailing edge portion of the blade facing in the opposite direction to the rotating direction, and an outer periphery of the blade facing the boss portion. In the projection view of projecting the axial blower on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference constituted by a portion, the rotation axis O and the blade outer peripheral radius on the blade front edge portion are 40 to 75. A straight line O-1bs 'connecting the point 1bs' which is a radius of 10% in the rotational direction around the origin O is 10 to 40 [deg.].
And an intersection 1bb 'between the straight line O-1bs' and the boss part side surface, which is the boss part radius, and the above 1b
Since the tangent at s' is formed in such a manner that the tangent line in the rotation direction is formed as a knotted blade front edge with an arbitrary curve that becomes concave, at the time of high pressure loss, near the boss portion of the blade front edge portion Due to the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 of a certain 1bs'-1bb ', the flow is blown to the outside along the blade surface, and the suction flow is guided outside by the vertical vortex. Thereby, disturbance of the flow on the blade negative pressure surface due to separation of the suction flow near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced.

Embodiment 7 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 40 is a perspective view showing an embodiment of the axial blower according to the present invention, which has a three-blade shape, for example, and its operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 41 is a front view of FIG. FIG.
FIG. 3 is a projection view in which a blade 1 is projected on a plane orthogonal to a rotation axis 3. In the figure, the same reference numerals as those in FIG. 41 denote the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the figure, the connecting portion between the leading edge of the blade and the boss is connected by an R curve having a radius of 15 to 35% of the radius Rt of the outer peripheral portion of the blade, and the blade shape is formed so as to be the leading edge of the blade. ing.

By forming in this way, at the time of high-pressure loss, FIG. 4 is a cross-sectional view taken along the line AA of the blade leading edge portion 1b 'in FIG.
In FIG. 3, the stable longitudinal vortex 10 generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow along the blade surface, and the suction flow 12 is guided by the longitudinal vortex 10 as shown in FIG. To the outside. Thus, as a problem in the conventional axial blower, FIG.
As described above, the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and the noise can be reduced.

In the conventional axial blower, as a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, the vicinity of the boss portion of the blade front edge portion 1b and the boss portion 2 as shown in FIG. In this connection, the thickness of the blade at the connection portion was partially increased to avoid stress concentration due to strong wind at the root of the blade, thereby preventing breakage. Therefore, as shown in FIG. 103, which is a developed view of the cross section taken along the line BB in FIG. 98, the suction flow 12 collides with the blade leading edge 1b having a large thickness, and the suction flow 11 on the negative pressure surface is disturbed. Was. In the present invention, the blade leading edge 1
Since the connection portion between b near the boss portion and the connection portion with the boss portion 2 has a large R curve, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness. However, if the radius RR of the R-curve at the connection between the blade front edge 1b and the boss 2 is too small or too large, noise deteriorates and strength is insufficient. Therefore, there is an optimum range of the radius RR of the R curve.

FIG. 45 shows the effect on the noise characteristics experimentally determined by the ratio (= RR / Rt) of the radius Rt of the radius of the R curve to the radius Rt of the outer periphery of the blade.
At this time, since the specific noise Ks changes depending on the operating point,
The value at the operating point where the specific noise Ks is minimum is defined as the minimum specific noise Ks.
Graphed as min. From FIG. 45, if the radius RR of the R curve is between 10% and 35% of the blade outer peripheral radius Rt, the minimum specific noise Ksmin is small and 1 [dB (A)] lower noise than the conventional one. is there. Further, FIG. 46 is a graph in which the value of the maximum stress σ near the boss portion of the blade front edge is experimentally obtained by the ratio (= RR / Rt) of the radius of the radius RR of the R curve to the radius Rt of the blade outer peripheral portion. It is. FIG.
Thus, the radius RR of the R curve is 15% of the blade outer peripheral radius Rt.
If it is above, it turns out that there is enough strength. Therefore,
45 and 46, if the radius RR of the R curve is between 15% and 35% of the blade outer peripheral radius Rt, low noise and sufficient strength are obtained.

This axial flow blower has a boss mounted on a blade and rotating, a blade leading edge facing in the rotating direction, a blade trailing edge facing in the direction opposite to the rotating direction, and a blade outer periphery facing the boss. In the projected view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference formed from the portion, the connecting portion between the blade front edge and the boss portion is set at 15% of the blade outer peripheral radius. Since the blade shape is formed so as to be a leading edge of the blade by being connected by an R curve having a radius of about 35%, at the time of high pressure loss, in the portion of the blade leading edge 1b 'near the boss, The vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow is blown to the outside while being guided by the vertical vortex. Due to separation of the suction flow near the part 1b The turbulence of the flow on the blade negative pressure surface 8 can be eliminated, the noise can be reduced, and when the fan is forcibly rotated at a high speed by a strong wind such as a typhoon, the boss portion of the blade front edge 1b is shifted toward the boss. The thickness of the blade at the connection between the vicinity and the boss 2 is partially increased to avoid stress concentration due to strong wind at the root of the blade, and to prevent damage to the blade front edge 1b near the boss. Since the connection between the and the boss has a large R curve, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

Embodiment 8 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 47 is a perspective view showing an embodiment of an axial blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 48 is a front view of FIG.

FIG. 49 is a projection view in which the blade 1 is projected on a plane orthogonal to the rotation axis 3. In the figure, the same components as those in FIG. 48 indicate the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. In the figure, the blade outer radius Rt and the blade boss radius Rb of the base blade 1O 'indicated by broken lines in the figure are shown.
A point 1bs'(1bs': blade front edge boss extension start point) on the blade front edge 1bO 'having an arbitrary radius Rs between
Blade leading edge 1b with boss radius Rb, which is the root of the blade
A straight line 1baO 'connecting the point 1baO' on O 'and the origin O
−O to the angle δαb (δα
b: Point 1 when rotated by the blade leading edge boss forward extension angle)
When bb ′ (1bb ′: blade leading edge boss extension end point), the straight line 1baO′-O is rotated by an arbitrary angle δα between 0 ° and the blade leading edge boss portion advance extension angle δαb,
Assuming that a point 1bc 'at an arbitrary radius Rc between the radius Rb and the radius Rs when extending in the blade outer peripheral direction, the radial distribution of the arbitrary rotation angle δα at this time is δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs), and the base blade 1 is continuous with the blade.
With reference to the blade front edge portion 1bO 'of O', the blade front edge boss portion extension end point 1b of the radius Rs passes through the point 1bc 'from the blade front edge boss portion extension start point 1bs' and the boss portion radius Rb.
The blade front edge portion 1bO 'between b' is advanced in the rotation direction to form a blade shape.

FIG. 50 shows a case where the blade surface is formed with the chord line center point PbO ′ at the boss radius Rb of the base blade 1O ′ indicated by the broken line in FIG. 49 as a relative origin. FIG. 3 is a development view obtained by cutting the blade 1O ′ of the base with a cylindrical surface having a boss radius Rb and developing the cross section into a two-dimensional plane. The solid line indicates the blade 1 of the present invention. In the figure, the sled line 5 of the base blade is formed in an arc shape, the sled angle θ which is the central angle for forming the arc, and the radius of the arc formed are RR. As described above, the blade of the axial blower according to the present invention is different from the base blade 10 in the straight line 1ba shown in FIG.
The point 1bb 'at the boss radius Rb when the O'-O is rotated by δαb in the rotation direction about the origin O is extended to the point 1bb in the developed view of FIG. 50 by the same arc in the rotation direction. .

By forming in this manner, at the time of high-pressure loss, FIG.
In FIG. 52, a stable vertical vortex 10 generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow 12 is guided by the vertical vortex 10 as shown in FIG. It is sent to the outside. Thus, as a problem in the conventional axial blower, FIG.
As described above, the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and the noise can be reduced. Further, in the conventional axial blower, as a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, as shown in FIG. The thickness of the blades was partially increased to avoid stress concentration due to strong wind at the roots of the blades, thereby preventing breakage. Therefore, FIG. 10 is a developed view in which the BB section of FIG. 98 is developed.
As shown in FIG. 3, the suction flow 12 collided with the blade leading edge 1b having a large thickness, and the suction flow 11 on the negative pressure surface was disturbed. In the present invention, since the connection between the blade 1 and the boss portion is formed in the shape of a blade in the form of an R shape as shown in FIG. 37, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

However, if the blade boss forward extension angle δαb and the radius Rs at the blade front edge boss extension start point 1bs ′ when the straight line 1ba′-O is rotated around the origin O are too large, FIG. As shown in FIG. 53, the suction flow 12 collides at the leading edge 1bb of the blade, causing turbulence on the blade surface and deteriorating noise. If it is too small, the effect is lost and the strength is insufficient. Therefore, there is an optimum range of the angle δαb and the radius Rs. FIG. 54 shows experimentally the influence on the noise characteristics obtained by the magnitude of the blade front edge boss forward extension angle δαb when the radius Rs is constant at the blade front edge boss extension start point 1bs. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, when the blade front edge boss portion advance extension angle δαb is between 20 ° and 50 °, the minimum specific noise Ksmi is smaller than that of the conventional axial flow fan which is the base blade.
The value of n is small, and the noise is 2.5 [dB (A)] at maximum.

FIG. 55 shows a blade leading edge boss forward extension angle δα.
When b = constant, the effect on the noise characteristics is experimentally determined by the magnitude of the ratio (= Rs / Rt) between the radius Rs at the blade leading edge boss portion extension start point 1bs' in FIG. 49 and the blade outer radius Rt. It is what we asked for. At this time, the specific noise Ks
Varies with the operating point, and the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss portion extension start point 1bs' is 4 times the blade outer peripheral radius Rt.
If it is between 0 and 70%, the minimum specific noise Ksmin is low, and the maximum noise is 2.5 [dB (A)] lower than that of the conventional axial fan which is the base blade. FIG. 56 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs to the blade outer periphery radius Rt at the blade leading edge boss extension start point 1bs (= Rs / Rt) and the effect of the blade leading edge boss forward extension angle δαb on the noise characteristics. This is a graph obtained by examining the values at the operating point where the specific noise Ks is minimized. From the figure, 0.4 ≦ Rs / Rt ≦ 0.7 and 20 ° ≦ δα
If b ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and the maximum noise is 2.5 [dB (A)] low.

FIG. 57 shows a blade leading edge boss portion extension start point 1b.
The effect of the ratio of the radius Rs to the radius Rt of the blade outer periphery at s and the maximum stress σ on the blade of the blade front edge boss portion extension elongation angle δαb is experimentally examined. The black circles showing the values of Rb / Rt in the figure are the maximum stresses when the plate thickness is not locally increased at the portion from the boss portion at the leading edge of the blade of the axial flow blower as the base blade. As shown in the figure, if 0.4 ≦ Rs / Rt and 20 ° ≦ δαb, the blade strength is sufficient.
Therefore, from FIGS. 56 and 57, 0.4 ≦ Rs / Rt ≦ 0.7 and 2
If 0 ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

An axial flow blower according to the present invention is characterized in that a boss portion to which a blade is attached and rotated, a blade front edge portion facing in the rotation direction, a blade rear edge portion facing in a direction opposite to the rotation direction, and the boss portion. In a projection view of projecting the axial flow fan on a plane orthogonal to the rotation axis of the axial flow fan having a blade whose circumference is formed from the opposing blade outer peripheral portion, the rotation axis is the origin O,
Point 1baO 'on the leading edge of the blade at the root of the blade and origin O
The point 1bb 'of the boss portion radius Rb when the straight line 1baO'-O connecting the points is rotated by an angle δαb between 20 and 50 ° around the origin O and the radius 4
Point 1bs' on blade leading edge with radius Rs of 0-70%
The boss portion radius Rb when the shape of the boss portion is rotated from the point 1ba ′ on the blade front edge which is the boss portion radius Rb of the blade by the angle δαb with respect to the blade front edge portion as a reference. the linear 1bc '-O and linear 1Ba'-O connecting the origin O and' 1bc point radius Rc between the boss portion radially Rb~ radius Rs that exists between 'the blade leading 1bb point on the edge The radial distribution of δα indicating the angle formed is represented by δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs), and a blade shape is formed by extending the blade front edge portion closer to the boss portion from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. It is.

The axial flow blower according to the present invention is characterized in that a boss portion to which a blade is attached and rotated, a blade front edge portion facing in the rotation direction, a blade rear edge portion facing in the opposite direction to the rotation direction, and the boss portion are provided. In a projection view of projecting the axial flow fan on a plane orthogonal to the rotation axis of the axial flow fan having a blade whose circumference is formed from the opposing blade outer peripheral portion, the rotation axis is the origin O,
Point 1baO 'on the leading edge of the blade at the root of the blade and origin O
The point 1bb 'of the boss portion radius Rb when the straight line 1baO'-O connecting the points is rotated by an angle δαb between 20 and 50 ° around the origin O and the radius 4
Point 1bs' on blade leading edge with radius Rs of 0-70%
Is defined as a point 1baO ′ on the blade front edge which is the boss radius Rb of the blade with respect to the blade front edge.
And the point 1bc ' of the radius Rc between the boss radius Rb and the radius Rs existing between the point 1bb' on the blade leading edge with the boss radius Rb when rotated in the rotation direction by the angle δαb.
1bc'- O and 1baO '
Δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs), and the blade front edge of the portion closer to the boss portion is extended in the rotation direction from point 1bs ′ on the blade front edge so as to be continuous with the blade, thereby forming a blade shape. Therefore, at the time of high pressure loss, in the portion near the boss portion of the leading edge of the blade, the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow along the blade surface and the suction flow. The air is blown to the outside while being guided by the vertical vortex, and the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced. As a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, the thickness of the blade near the boss at the leading edge of the blade and at the connection with the boss is partially increased, Avoid stress concentration due to strong wind at the base of Without preventing, since they are the connection portion of the blade 1 and the boss portion forming the blade shape R shape Gimi, you can avoid stress concentration, it is not necessary to increase the plate thickness locally.

The axial-flow blower according to the present invention is characterized in that a boss portion to which the blades are attached and rotated, a blade front edge portion facing in the rotation direction, a blade rear edge portion facing in the opposite direction to the rotation direction, and the boss portion. In a projected view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is formed from opposing blade outer peripheral portions, a point 1ba ′ on the blade front edge of the root of the blade is shown. Straight line 1ba'-O connecting the origin O
Is rotated by an angle δαb between 20 ° and 50 ° in the rotation direction about the origin O, the point 1b of the boss radius Rb
The shape between b ′ and a point 1bs ′ on the leading edge of the blade having a radius Rs of 40 to 70% of the radius of the outer peripheral portion of the blade is the boss radius Rb of the blade with respect to the leading edge of the blade. Point 1 on the blade front edge of boss radius Rb when rotated in the rotation direction by the angle δαb from point 1ba ′ on the blade front edge
straight 1bc connecting the origin O and 'point 1bc radius Rc between the boss portion radially Rb~ radius Rs that exists between the' bb '-
Δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² represents the radial distribution of δα indicating the angle between O and the straight line 1ba′-O. (Rb ≦ R ≦ Rs), and the blade front edge of the portion closer to the boss portion is extended in the rotation direction from point 1bs ′ on the blade front edge so as to be continuous with the blade, thereby forming a blade shape. Therefore, at the time of high pressure loss, in the portion near the boss portion of the leading edge of the blade, the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow along the blade surface and the suction flow. The air is blown to the outside while being guided by the vertical vortex, and the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced. As a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, the thickness of the blade near the boss at the leading edge of the blade and at the connection with the boss is partially increased, Avoid stress concentration due to strong wind at the base of Without preventing, since they are the connection portion of the blade 1 and the boss portion forming the blade shape R shape Gimi, you can avoid stress concentration, it is not necessary to increase the plate thickness locally.

Embodiment 9 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 58 is a perspective view showing one embodiment of an axial blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
3 indicates the rotation axis of the blade 1 and 4 indicates the rotation direction.

FIG. 59 is a front view of FIG. In this figure, L is a chord length and indicates a circumferential distance (pitch) T between the blades. Ls is the blade outer radius R
The chord length passing through a point 1bs on the blade leading edge 1b with a radius Rs of 40 to 60% of t is shown. FIG.
FIG. 4 is a projection view of the blade 1 projected on a plane orthogonal to FIG. In the figure, the same components as those in FIG. 59 indicate the same components.
1 'is the blade in the projection, 1b' is the leading edge of the blade in the projection, 1c 'is the trailing edge of the blade in the projection, 1d'
Is the outer periphery of the blade in the projection view. A blade leading edge 1b having an arbitrary radius Rs between the blade outer radius Rt and the blade boss radius Rb of the base blade 1O 'indicated by a broken line in the figure.
Point 1bs' on O '(1bs': blade front edge boss extension start point), straight line 1b connecting origin 1 O with point 1baO' on blade front edge 1bO 'with boss radius Rb, which is the root of the blade
aO′−O is converted to an angle δαb
(Δαb: blade front edge boss forward extension angle) When rotated by the point 1bb ′ (1bb ′: blade front edge boss extension end point), from the radius Rs at the blade front edge boss extension start point The blade chord length is extended in the rotation direction up to the radius Rb at the blade leading edge boss portion extension end point 1bb '. Also, an arbitrary radius R between the radius Rs and the boss radius Rb.
The point on the blade leading edge 1b 'after the extension is 1bR'
And

FIG. 61 shows an arc 1ba at the boss radius Rb of the base blade 1O 'shown by the broken line in FIG.
When the blade surface is formed with the chord line center point PbO ', which is the middle point of O'-1cb', as a relative origin, the base blade 1O 'is cut by a cylindrical surface having a boss radius Rb, A development view obtained by developing the cross section into a two-dimensional plane is shown. The solid line indicates the blade 1 of the present invention. In the figure, the sled line 5 of the base blade is formed in an arc shape, the sled angle θ which is a central angle for forming the arc, and the radius forming the arc is RRO.
In the figure, the blade 1 is different from the base blade 10 in the drawing.
Boss radius R with the same sled angle θ and stagger angle ξ
b, the chord length LbO at the boss radius Rb of the blade 10 and the chord length LbO and the point 1bb are extended to the blade front edge boss portion extension end point 1bb 'shown in FIG.
-Chord length Lb up to the trailing edge 1cb of the blade,
(= Lb−LbO), and the blade boss portion extension start point 1bs
Is the chord length Ls at the radius Rs, the radial distribution of the chord length L from the boss radius Rb to the radius Rs is L = △ Lb / (Rs−Rb) ² × (R−Rs) ² + Ls (Rb ≦ R ≦ Rs) to form a blade shape.

By forming in this manner, the chord length becomes longer than that of the base blade 10 as shown in FIG. 61, and a pressure increase on the blade surface can be obtained.
62, which is a cross section taken along line XX of FIG.
0, the flow is on the blade surface and the suction flow 1
While being guided by the vertical vortex 10, the air 2 is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, as shown in FIG. 101, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced.

In the conventional axial flow blower, as a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, the vicinity of the boss portion of the blade front edge 1b and the boss portion 2 as shown in FIG. In this connection, the thickness of the blade at the connection portion was partially increased to avoid stress concentration due to strong wind at the root of the blade, thereby preventing breakage. Therefore, as shown in FIG. 102, which is a developed view of the cross section taken along the line BB of FIG. 97, the suction flow 12 collides at the blade leading edge 1b having a large thickness, and the suction flow 11 on the negative pressure surface is disturbed. Was. In the present invention, since the connecting portion between the blade 1 and the boss portion is formed in the shape of a blade in the shape of an R as shown in FIG. 60, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

However, the straight line 1ba O'- O is
Blade boss forward extension angle δαb when rotating to center
That is, if the chord length Lb at the boss radius Rb is too large, the blade trailing edge 1 in FIG. 64 corresponding to FIG.
In the vicinity of cb , the flow 11 and the vertical vortex 10 on the blade suction surface 8 cause separation from the blade suction surface 8, or the entire circumference of the axial flow blower shown in FIG. Is developed into a two-dimensional plane, the flow 11 on the suction surface where the suction surface 8 of the blade 1 is peeled off and the pressure surface of the blade 1N where the vertical vortex 10 next turns are shown. The 9N flow 13 is disturbed and noise is deteriorated. If the radius Rs at the blade leading edge boss portion extension start point 1bs' is too small, the effect is lost and the strength is insufficient.

Therefore, there is an optimum range of the angle δαb and the radius Rs. FIG. 66 shows the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks [dB (A)] of the conventional axial blower as the base and the axial blower according to the ninth embodiment of the present invention. FIG. In the figure, black circles and black squares show the characteristics and the minimum specific noise of the conventional axial flow fan, and x and □ show the characteristics and the minimum specific noise of the axial flow fan in one embodiment of the ninth invention. As can be seen from this characteristic diagram, the operating region extends to the low air volume side and higher static pressure is achieved as a whole as compared with the related art. On the other hand, the specific noise Ks can be reduced by a maximum of 3 [dB (A)] and is low noise.

FIG. 67 shows a blade leading edge boss portion extension starting point 1b.
The influence on the noise characteristics was experimentally obtained by the magnitude of the blade front edge boss portion advance extension angle δαb when the radius Rs at s = constant. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, the blade leading edge boss portion advance extension angle δαb
Is between 20 ° and 50 °, the value of the minimum specific noise Ksmin is smaller than that of the conventional axial blower as the base blade, and the maximum noise is 3.0 [dB (A)].

FIG. 68 shows a blade leading edge boss forward extension angle δα.
When b = constant, the effect on noise characteristics is experimentally determined by the magnitude of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss portion extension start point 1bs' in FIG. 60 to the blade outer radius Rt. It is what we asked for. At this time, the specific noise Ks
Varies with the operating point, and the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss portion extension start point 1bs' is 4 times the blade outer peripheral radius Rt.
If it is between 0 and 60%, the minimum specific noise Ksmin is low, and the maximum noise is 3.0 [dB (A)] lower than that of the conventional axial blower which is the blade of the base. FIG. 69 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs to the blade outer peripheral radius Rt at the blade leading edge boss extension start point 1bs (= Rs / Rt) and the effect of the blade leading edge boss forward extension angle δαb on the noise characteristics. This is a graph obtained by examining the values at the operating point where the specific noise Ks is minimized.

As shown in the figure, 0.4 ≦ Rs / Rt ≦ 0.6 and 20 °
If ≦ δαb ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and low noise. FIG. 70 experimentally examined the influence of the ratio of the radius Rs to the blade outer peripheral radius Rt at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss forward extension angle δαb on the maximum stress σ on the blade. Things. R in the figure
The black circle indicating the value of b / Rt is the maximum stress when the plate thickness is not locally increased from the boss portion at the blade front edge portion of the axial flow blower as the base blade. From the figure, 0.4 ≦ R
If s / Rt and 20 ° ≦ δαb, the blade strength is sufficient. Therefore, from FIGS. 69 and 70, 0.4 ≦ Rs / Rt
If ≦ 0.6 and 20 ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

The axial blower according to the present invention is characterized in that a boss portion to which the blades are attached and rotated, a blade front edge portion facing in the rotation direction, a blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view of projecting the axial flow fan on a plane orthogonal to the rotation axis of the axial flow fan having a blade whose circumference is formed from the opposing blade outer peripheral portion, the rotation axis is the origin O,
A straight line 1baO'- connecting the point 1baO 'on the leading edge of the blade at the boss radius Rb of the blade 1O' of the base to the origin O.
When the point O is rotated by an angle δαb between 20 and 50 ° in the direction of rotation about the origin O as the center, the blade front edge boss portion extension end point 1bb ′ is defined, and the blade is a cylindrical surface having an arbitrary radius R. In a developed view obtained by expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is changed to the point 1bb while the blade 1O has the same warp angle θ and stagger angle ξ.
And the boss radius Rb of the blade 10 at this time.
Chord length LbO and point 1bb to blade trailing edge 1C
a point 1 on the leading edge of the blade at a radius Rs of 40 to 60% of the outer peripheral radius of the blade.
Assuming that the chord length Ls at bs, the radial distribution of the chord length L from the boss radius Rb to the point 1bs on the blade leading edge is L = △ Lb / (Rs−Rb) ² × (R− Rs) ² + Ls (Rb ≦ R ≦ Rs) to form a blade shape.

An axial flow blower according to a ninth aspect of the present invention provides a boss portion to which the blades are attached and rotated, a blade front edge portion facing the rotation direction, a blade rear edge portion facing the rotation direction, and the boss. In the projection view of the axial flow blower projected on a plane orthogonal to the rotation axis of the axial flow blower having a blade configured from the outer periphery of the blade facing the portion, the rotation axis is the origin O,
A straight line 1baO'- connecting the point 1baO 'on the leading edge of the blade at the boss radius Rb of the blade 1O' of the base to the origin O.
When the point O is rotated by an angle δαb between 20 and 50 ° in the direction of rotation about the origin O as the center, the blade front edge boss portion extension end point 1bb ′ is defined, and the blade is a cylindrical surface having an arbitrary radius R. In a developed view obtained by expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is changed to the point 1bb while the blade 1O has the same warp angle θ and stagger angle ξ.
And the boss radius Rb of the blade 10 at this time.
Chord length LbO and point 1bb to blade trailing edge 1c
a point 1 on the leading edge of the blade at a radius Rs of 40 to 60% of the outer peripheral radius of the blade, where chord length Lb up to b is ΔLb.
Assuming that the chord length Ls at bs, the radial distribution of the chord length L from the boss radius Rb to the point 1bs on the blade leading edge is L = △ Lb / (Rs−Rb) ² × (R− Rs) ² + Ls (Rb ≦ R ≦ Rs), and the blade shape is formed. Therefore, the chord length is longer than that of the base blade 10 and the pressure rise on the blade surface is increased, and the high pressure loss is obtained. At the time, at a portion of the blade leading edge near the boss, a vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow is guided by the vertical vortex. The turbulent air is blown to the outside, and the turbulence of the flow on the blade negative pressure surface due to the separation of the suction flow near the leading edge of the blade at high pressure loss can be eliminated, noise can be reduced, and forced by strong wind such as typhoon When the fan rotates at high speed,
The thickness of the blade near the boss near the blade front edge and at the connection with the boss is partially increased to avoid stress concentration due to strong wind at the root of the blade and prevent damage to the blade and boss. Since the connecting portions of the portions are formed in the shape of a wing in the form of an R shape, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

The axial-flow blower according to the present invention is characterized in that a boss mounted with a blade and rotating, a blade leading edge facing in the rotating direction, a blade trailing edge facing in the direction opposite to the rotating direction, and the boss. In a projected view of the axial blower projected on a plane orthogonal to the rotation axis of the axial blower having a blade having a circumference formed from the outer periphery of the facing blade, the blade front edge at the boss radius Rb of the base blade 1O 'is shown. The point at which the straight line 1baO'-O connecting the point 1baO 'on the part and the origin O is rotated about the origin O by an angle δαb between 20 and 50 ° in the rotation direction is defined as the blade leading edge boss. When the extension end point is 1bb ', the blade is cut by a cylindrical surface having an arbitrary radius R, and its cross section is 2
In a developed view obtained by developing the blade into a three-dimensional plane, the chord at the boss radius Rb is extended to the point 1bb while the blade 1O has the same warp angle θ and stagger angle 、, and the blade Chord length LbO at boss radius Rb of 10
And the chord length Lb from the point 1bb to the blade trailing edge 1cb ,
Assuming that this difference is ΔLb and the chord length Ls at a point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the radius of the outer peripheral portion of the blade, the boss radius Rb indicates Point 1b
The radial distribution of the chord length L up to s is given by L = △ Lb / (Rs−Rb) ² × (R−Rs) ² + Ls (Rb ≦ R ≦ Rs), and the blade shape is formed. The chord length is longer than that of the base blade 10 to increase the pressure on the blade surface, and at the time of high pressure loss, the flow from the pressure surface 9 to the suction surface 8 at a portion of the blade front edge near the boss. Due to the vertical vortex generated by the swirl, the flow is along the blade surface and the suction flow is blown to the outside while being guided by this vertical vortex, and the blade flow due to the separation of the suction flow near the leading edge of the blade at high pressure loss The turbulence of the flow on the pressure surface can be eliminated, noise can be reduced, and as a countermeasure when the fan is forcibly rotated at high speed due to strong wind such as typhoon,
The thickness of the blade near the boss near the blade front edge and at the connection with the boss is partially increased to avoid stress concentration due to strong wind at the root of the blade and prevent damage to the blade and boss. Since the connecting portions of the portions are formed in the shape of a wing in the form of an R shape, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

Embodiment 10 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 71 is a perspective view showing an embodiment of the axial flow blower according to the present invention, which has, for example, a three-blade shape. The operation is mainly described for one blade 1, but the same applies to other blades. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 72 is a front view of FIG. 71. In the figure, L is a chord length, and the value of the chord ratio T / L defined by the ratio to T, which is the circumferential distance (pitch) between the blades, is T / L = 1. 1 to 2.0. FIG. 73
FIG. 3 is a projection view in which a blade 1 is projected on a plane orthogonal to a rotation axis 3. In the figure, the same reference numerals as those in FIG. 72 denote the same components. 1 'is a blade in the projection, 1b' is a blade leading edge in the projection, 1c 'is a blade trailing edge in the projection, and 1d' is a blade outer periphery in the projection. Also,
The broken line in the figure indicates the blade 1O 'serving as a base when forming the blade 1' of the axial blower according to the present invention, wherein 1bO 'is the blade front edge of the base blade and 1dO' is the blade of the base blade. The outer peripheral portion, 1cO ′ , indicates the trailing edge of the base blade.

Further, an arc 1bRO'-PR in a developed view obtained by cutting the base blade 1O 'with a cylindrical surface having an arbitrary radius R from the rotation shaft 3 and developing the cross section into a two-dimensional plane.
O'-1cRO 'has a blade cross-sectional shape. Where P
RO 'is the midpoint of the arc 1bRO'-1cRO', and is the center point of the chord line in the projection of the blade 1O 'on a plane orthogonal to the rotation axis 3. PRO 'in this projection
In order to clarify the position, the blade 1O ′ is cut by a cylindrical surface having a boss radius Rb, and the boss chord line center point PbO ′ in a developed view obtained by expanding the cross section into a two-dimensional plane, A straight line Pb connecting the position O in the projected view of the rotation axis 3
A coordinate system having O'-O as the X axis and O as the origin is formed in the projection view. PtO 'is a chord center point of the blade outer peripheral portion 1dO' at the blade outer peripheral portion radius Rt. In the above coordinate system, the angle between the straight line PRO′-O and the X axis is δ
θ (δθ: advancing angle in the rotation direction), the angle between the X-axis and a straight line PtO′-O connecting the chord center point PtO ′ and the origin O at the outer periphery of the blade is δθt, and δθ = δθt × (R -Rb) / (Rt-Rb),
δθt = 25 to 40 °.

The axial flow blower according to the present invention has a blade outer radius R of a base blade 1O 'indicated by a broken line in the figure.
Point 1bs'(1bs': blade front edge boss portion extension start point) on blade front edge portion 1bO 'having arbitrary radius Rs between t and blade boss portion radius Rb, boss portion radius Rb which is the root of the blade A straight line 1baO'-O connecting the point 1baO 'on the blade leading edge 1bO' and the origin O is rotated about the origin O by the angle δαb (δαb: blade leading edge boss forward extension angle) in the rotation direction. When the point 1bb '(1bb': blade front edge boss portion extension end point) at the time of
A point 1bc 'at an arbitrary radius Rc between the radius Rb and the radius Rs when the blade is rotated by an arbitrary angle δα between the blade leading edge boss portion advance extension angle δαb and extended toward the blade outer peripheral portion.
Then, the radial distribution of the arbitrary rotation angle δα at this time is represented by δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs), and the base blade 1 is continuous with the blade.
With reference to the blade front edge portion 1bO 'of O', the blade front edge boss portion extension end point 1b of the radius Rs passes through the point 1bc 'from the blade front edge boss portion extension start point 1bs' and the boss portion radius Rb.
The blade front edge portion 1bO 'between b' is advanced in the rotation direction to form a blade shape.

FIG. 74 shows a case where the blade surface is formed with the chord line center point PbO ′ at the boss radius Rb of the base blade 1O ′ indicated by the broken line in FIG. 73 as a relative origin. FIG. 3 is a development view obtained by cutting the blade 1O ′ of the base with a cylindrical surface having a boss radius Rb and developing the cross section into a two-dimensional plane. The solid line indicates the blade 1 of the present invention. In the figure, the sled line 5 of the base blade is formed in an arc shape, the sled angle θ which is the central angle for forming the arc, and the radius of the arc formed are RR. At this time, the radial distribution of the warp angle θ is represented by θ =
(Θt−θb) × (R−Rb) / (Rt−Rb) + θb
(Θt: deflection angle at the blade outer peripheral portion, θb: deflection angle at the blade boss portion), θt = 25 to 35 °, θb = 30 to 5
5 ° and θt <θb. In addition, the mounting position of the blade is defined as an angle between a chord line 1baO- 1cO and a straight line 6 that is parallel to the rotation axis 3 and passes through the blade front edge 1baO of the base blade 1O. It is determined by giving a distribution of directions. That is, the radial distribution of ξ is given by ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery, ξ
b: stagger angle at the blade boss) and Δt = 55-7
0 °, ξb = 40 to 65 °, and ξt> ξb. In contrast to the base blade 1O, the blade of the axial blower according to the present invention has a boss radius R when the straight line 1baO'-O shown in FIG.
b in the development of FIG. 74 at point 1bb '
b is extended in the rotation direction by the same arc.

By forming in this manner, at the time of high-pressure loss, FIG.
In, due to the longitudinal vortex 10 generated by the flow of the flow from the pressure surface 9 to the suction surface 8, the flow follows the blade surface,
The suction flow 12 is blown to the outside as shown in FIG. 76 while being guided by the vertical vortex 10. Thus, as a problem in the conventional axial blower, as shown in FIG. 102, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced. Further, in the conventional axial blower, as a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, as shown in FIG. The thickness of the blades was partially increased to avoid stress concentration due to strong wind at the roots of the blades, thereby preventing breakage. Therefore, FIG. 98
As shown in FIG. 103 which is a developed view of the cross section taken along the line BB of FIG. 103, the suction flow 12 collides with the blade leading edge 1b having a large thickness, and the suction flow 11 on the negative pressure surface was disturbed. In the present invention, since the connecting portion between the blade 1 and the boss portion is formed in a blade shape with a rounded shape as shown in FIG. 73, stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

However, the straight line 1baO'-O is set at the origin O
Blade boss forward extension angle δαb when rotating to center
And radius Rs at the blade leading edge boss extension start point 1bs'
Is too large, the suction flow 12 collides at the leading edge 1bb of the blade as shown in FIG. 77 corresponding to FIG. 74, causing disturbance on the blade surface and deteriorating the noise.
And the strength is insufficient. Therefore, there is an optimum range of the angle δαb and the radius Rs. FIG. 78 shows experimentally the influence on the noise characteristics obtained by the magnitude of the blade front edge boss forward extension angle δαb when the radius Rs is constant at the blade front edge boss extension start point 1bs. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, when the blade leading edge boss portion advance extension angle δαb is between 20 ° and 50 °, the minimum specific noise Ksm is smaller than that of the conventional axial flow fan which is the base blade.
The value of in is small, and the noise is 2.5 [dB (A)] at maximum.

FIG. 79 shows the blade leading edge boss forward extension angle δα.
When b = constant, the effect on noise characteristics is experimentally determined by the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss portion extension start point 1bs' in FIG. 73 to the blade outer radius Rt. It is what we asked for. At this time, the specific noise Ks
Varies with the operating point, and the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss portion extension start point 1bs' is 4 times the blade outer peripheral radius Rt.
If it is between 0 and 70%, the minimum specific noise Ksmin is low, and the maximum noise is 2.5 [dB (A)] lower than that of the conventional axial fan which is the base blade. FIG. 80 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs to the blade outer periphery radius Rt at the blade leading edge boss extension start point 1bs (= Rs / Rt) and the effect of the blade leading edge boss forward extension angle δαb on the noise characteristics. This is a graph obtained by examining the values at the operating point where the specific noise Ks becomes minimum. From the figure, 0.4 ≦ Rs / Rt ≦ 0.7 and 20 ° ≦ δα
If b ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and the maximum noise is 2.5 [dB (A)] low. FIG. 81 shows the ratio of the radius Rs to the blade outer peripheral radius Rt at the blade leading edge boss extension start point 1bs and the blade leading edge boss forward extension angle δα.
The effect of b on the maximum stress σ on the blade is experimentally examined. The black circles showing the values of Rb / Rt in the figure are the maximum stresses when the plate thickness is not locally increased at the portion from the boss portion at the leading edge of the blade of the axial flow blower as the base blade. As shown in the figure, if 0.4 ≦ Rs / Rt and 20 ° ≦ δαb, the blade strength is sufficient. Therefore, from FIGS. 80 and 81, if 0.4 ≦ Rs / Rt ≦ 0.7 and 20 ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

This axial-flow blower has a boss portion to which the blades are attached and rotated, a blade front edge portion facing the rotation direction, a blade rear edge portion facing the rotation direction and a blade outer periphery facing the boss portion. In the developed view obtained by cutting the blade of the axial flow blower having the blade having the circumference from the part with a cylindrical surface having an arbitrary radius R, and developing the cross section into a two-dimensional plane, When the shape is an arc shape and the center angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (R−R
b) / (Rt−Rb) + θb (θt: sled angle at the outer periphery of the blade, θb: sled angle at the radius Rb of the blade boss portion), and θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt <
θb, and in the above developed view, when an angle between a chord line of the blade and a straight line parallel to the rotation axis and passing through the leading edge of the blade is denoted by ξ (ξ: stagger angle), the radial distribution of ξ Ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery 部, ξ
b: stagger angle at boss radius Rb), Δt
= 55 ° to 70 °, ξb = 40 ° to 65 °, and ξt> ξb, and L in this figure is the chord length and the circumferential distance (pitch) between the blades shown in FIG. T
The value of the chord ratio T / L defined by the ratio is defined as T / L = 1.1 to 2.0 at each radial point, and the axial flow fan is projected on a plane orthogonal to the rotation axis. In the figure, a chord line center point in a cross section when cut by a cylindrical surface having a boss portion radius Rb of the blade is Pb ′, and a line connecting the O point and the Pb ′ point is the origin of the rotation axis. In a coordinate system with the X axis, the chord line center point when the blade is cut by a cylindrical surface having an arbitrary radius R is PR ′, and the angle between the straight line PR′-O and the X axis is δθ (δθ: When the rotation angle advance angle is set, the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt−Rb) (Rt: radius of blade outer peripheral portion, Rb: radius of blade boss portion, δθ
t: the angle between the straight line Pt'-O and the X axis), δθt
Is set to 25 to 40 °, a blade shape is first formed, and a straight line 1baO′-O connecting the point 1baO ′ on the blade front edge of the root of the blade at this time to the origin O is rotated around the origin O. The point 1bb 'of the boss radius Rb when rotated by an angle δαb between 20 and 50 ° and the blade outer radius of
The shape between the points 1bs 'on the leading edge of the blade having a radius Rs of 70% is defined from the point 1baO' on the leading edge of the blade, which is the boss radius Rb of the blade with respect to the leading edge of the blade. The point 1bc ' of the radius Rc between the boss radius Rb and the radius Rs existing between the points 1bb' on the blade leading edge of the boss radius Rb when rotated in the rotation direction by the angle δαb and the origin O the radial distribution of .delta..alpha indicating the angle between the straight line 1bc '-O and linear 1baO'-O which connects the δα = (δαb / (Rb- Rs) 2) × (R-Rs) 2 (Rb ≦ R ≦ Rs), and the blade front edge of the portion closer to the boss portion is extended in the rotation direction from point 1bs ′ on the blade front edge so as to be continuous with the blade, thereby forming a blade shape. Therefore, at the time of high pressure loss, in the portion near the boss portion of the leading edge of the blade, the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow along the blade surface and the suction flow. The air is blown to the outside while being guided by the vertical vortex, and the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss can be eliminated, and noise can be reduced. As a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, the thickness of the blade near the boss at the leading edge of the blade and at the connection with the boss is partially increased, Avoid stress concentration due to strong wind at the base of Without preventing, since they are the connection portion of the blade 1 and the boss portion forming the blade shape R shape Gimi, you can avoid stress concentration, it is not necessary to increase the plate thickness locally.

Embodiment 11 Hereinafter, another embodiment will be described with reference to the drawings. FIG. 82 is a perspective view showing an embodiment of the axial flow blower according to the present invention, which has, for example, a three-bladed shape. It is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion for attaching the blade,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade front edge, 1d denotes a blade outer peripheral portion, and 1c denotes a blade rear edge. FIG. 83 is a plan view of FIG. In the figure, L is a chord length, and a value of a chord ratio T / L defined by a ratio with T which is a circumferential distance (pitch) between the blades at each radial point is given by:
T / L = 1.1 to 2.0.

FIG. 84 is a projection view in which the blade 1 and the blade 1O ′ serving as the base of the blade 1 ′ are projected on a plane orthogonal to the rotation axis 3. In the figure, the same reference numerals as those in FIG. 83 denote the same components. 1 'is the blade in the projection, 1b'
Is the leading edge of the blade in the projection, 1c 'is the trailing edge of the blade in the projection, and 1d' is the outer periphery of the blade in the projection. The broken line in the figure is a blade 1O 'serving as a base when forming the blade 1' of the axial blower according to the present invention, and 1b.
O 'denotes the leading edge of the base blade, 1dO' denotes the outer peripheral portion of the base blade, and 1cO ' denotes the trailing edge of the base blade. Further, the base blade 1O ′ is cut from the rotating shaft 3 with a cylindrical surface having an arbitrary radius R, and the cross-section thereof is expanded into a two-dimensional plane to obtain an arc 1bR in a developed view.
O'-PRO'-1cRO 'has a blade cross-sectional shape.
Here, PRO 'is the midpoint of the arc 1bRO'-1cRO', and is the center point of the chord line in the projection of the blade 1O 'projected on a plane orthogonal to the rotation axis 3. In order to clarify the position of PRO ′ in this projection, the boss radius Rb
A straight line connecting the boss chord line center point PbO 'in a developed view obtained by cutting the blade 1O' on the cylindrical surface of the above and developing the cross section into a two-dimensional plane, and the position O in the projected view of the rotation axis 3 A coordinate system with PbO'-O as the X axis and O as the origin is formed in the projection view. PtO 'is a chord center point of the blade outer peripheral portion 1dO' at the blade outer peripheral portion radius Rt. In the above coordinate system, an angle formed between the straight line PRO′-O and the X axis is δθ (δθ: advancing angle in the rotation direction), and a straight line Pt connecting the chord line center point PtO ′ and the origin O at the outer periphery of the blade.
The angle between O′-O and the X axis is δθt, and δθ = δθt
× (R−Rb) / (Rt−Rb), δθt = 25
４０40 °. The axial-flow blower according to the present invention has a blade outer peripheral radius Rt of the base blade 1O 'indicated by a broken line in the figure.
1b '(1bs': blade front edge boss extension start point) on the blade front edge 1bO' having an arbitrary radius Rs between the boss portion radius Rb and the boss portion radius R which is the root of the blade
b, a straight line 1baO'-O connecting the point 1baO 'on the blade leading edge 1bO' and the origin O is rotated by an angle δαb (δαb: blade leading edge boss forward extension angle) in the rotation direction about the origin O. When the point 1bb ′ (1bb ′: blade leading edge boss portion extension end point) at this time is set, the distance from the radius Rs at the blade leading edge boss portion extension start point to the radius Rb at the blade leading edge boss portion extension end point 1bb ′ is set. The shape is such that the chord length of the blade is extended in the rotation direction. This is described in detail in the following figure.

FIG. 85 shows the case where the blade surface is formed with the chord line center point PbO ′ at the boss radius Rb of the base blade 1O ′ indicated by the broken line in FIG. 84 as a relative origin. FIG. 3 is a development view obtained by cutting the blade 1O ′ of the base with a cylindrical surface having a boss radius Rb and developing the cross section into a two-dimensional plane. The solid line indicates the blade 1 of the present invention. In the figure, the sled line 5 of the base blade is formed in an arc shape, the sled angle θ which is a central angle for forming the arc, and the radius forming the arc is RRO. At this time, the radial distribution of the warp angle θ is θ
= (Θt−θb) × (R−Rb) / (Rt−Rb) + θ
b (θt: slew angle at the outer periphery of the blade, θb: slew angle at the blade boss), θt = 25 to 35 °, θb = 30 to
55 ° and θt <θb. In addition, the mounting position of the blade is defined as an angle between a chord line 1baO- 1cO and a straight line 6 that is parallel to the rotation axis 3 and passes through the blade front edge 1baO of the base blade 1O. It is determined by giving a distribution of directions. That is, the radial distribution of ξ is given by ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery, ξ
b: stagger angle at the blade boss) and Δt = 55-7
0 °, ξb = 40 to 65 °, and ξt> ξb. In contrast to such a base blade 10, the blade 1 of the axial blower according to the present invention has a sled angle θ and a stagger angle と with the blade 10.
While the chord at the boss radius Rb is extended in the rotational direction to the blade leading edge boss extension extension end point 1bb ′ shown in FIG. 84, and the chord at the boss radius Rb of the blade 1O in this drawing is obtained. The length LbO and the chord length Lb from the point 1bb to the blade trailing edge 1cb , and this difference is defined as △ Lb (= Lb−LbO),
Assuming the chord length Ls at the radius Rs at the blade boss portion extension start point 1bs, the radial distribution of the chord length L from the boss portion radius Rb to the radius Rs is L = △ Lb / (Rs−Rb) ² × (R−Rs) ² + Ls (Rb ≦ R ≦ Rs) to form a blade shape.

By forming as described above, the chord length is longer than that of the base blade 10 as shown in FIG. 85, and a pressure increase on the blade surface can be obtained.
86, which is a YY cross section of FIG. 86, a stable longitudinal vortex 1 generated by the flow
0, the flow is on the blade surface and the suction flow 1
87 is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, as shown in FIG. 102, it is possible to eliminate the disturbance of the flow 11 on the blade negative pressure surface 8 due to the separation of the suction flow 12 near the blade leading edge 1b at the time of high pressure loss. In addition, noise can be reduced. Further, in the conventional axial blower, as a countermeasure when the fan is forcibly rotated at a high speed due to a strong wind such as a typhoon, as shown in FIG. The thickness of the blades was partially increased to avoid stress concentration due to strong wind at the roots of the blades, thereby preventing breakage. Therefore, as shown in FIG. 103, which is a developed view of the cross section taken along the line BB in FIG. 98, the suction flow 12 collides with the blade leading edge 1b having a large thickness, and the suction flow 11 on the negative pressure surface is disturbed. Was. In the present invention, FIG.
As shown in FIG. 4, since the connection between the blade 1 and the boss portion is formed in the shape of a blade with an R shape, stress concentration can be avoided,
There is no need to locally increase the plate thickness.

However, when the straight line 1ba'-O is rotated about the origin O in the rotational direction, the blade boss portion advance extension angle δαb, that is, if the chord length Lb at the boss portion radius Rb is too large, FIG. At the blade trailing edge 1cb
In the vicinity, the flow 11 and the longitudinal vortex 10 on the blade negative pressure surface 8 cause separation from the blade negative pressure surface 8, or the entire circumference of the axial flow blower shown in FIG. As shown in the expanded view obtained by expanding to a two-dimensional plane,
The flow 11 on the suction surface where the suction surface 8 of the blade 1 is separated and the flow 1 on the pressure surface 9N of the blade 1N in which the vertical vortex 10 turns next.
3 is disturbed, noise is deteriorated, and if the radius Rs at the blade leading edge boss portion extension start point 1bs' is too small, the effect is lost and the strength is insufficient. Therefore, there is an optimum range of the angle δαb and the radius Rs.

FIG. 90 is a graph showing the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks between the conventional axial fan and the axial fan according to the eleventh embodiment of the present invention.
FIG. 9 is a characteristic diagram obtained by experimentally obtaining [dB (A)]. The black circles and black squares in the figure indicate the characteristics and minimum specific noise of the conventional axial blower.
X and □ show the characteristics and the minimum specific noise of the axial blower in one embodiment of the eleventh invention. As can be seen from this characteristic diagram, the operating region extends to the low air volume side and higher static pressure is achieved as a whole as compared with the related art. On the other hand, the specific noise Ks can be reduced by a maximum of 3 [dB (A)] and is low noise. FIG. 91 shows the effect on the noise characteristics experimentally determined by the magnitude of the blade front edge boss forward extension angle δαb when the radius Rs is constant at the blade front edge boss extension start point 1bs. At this time, since the specific noise Ks changes depending on the operating point, the value at the operating point at which the specific noise Ks is minimized is set to the minimum specific noise Ksm.
Graphed as in. As shown in the figure, when the blade leading edge boss portion advance extension angle δαb is between 20 ° and 50 °, the value of the minimum specific noise Ksmin is smaller than that of the conventional axial flow 0.0 [dB (A)]
Low noise.

FIG. 92 shows a blade leading edge boss portion advance extension angle δα.
When b = constant, the influence on the noise characteristics is experimentally determined by the magnitude of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss portion extension start point 1bs ′ in FIG. 47 and the blade outer radius Rt. It is what we asked for. At this time, the specific noise Ks
Varies with the operating point, and the value at the operating point where the specific noise Ks is minimized is graphed as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss portion extension start point 1bs' is 4 times the blade outer peripheral radius Rt.
If it is between 0 and 60%, the minimum specific noise Ksmin is low, and the maximum noise is 3.0 [dB (A)] lower than that of the conventional axial blower which is the blade of the base. FIG. 93 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs to the blade outer periphery radius Rt at the blade leading edge boss extension start point 1bs (= Rs / Rt) and the effect of the blade leading edge boss forward extension angle δαb on the noise characteristics. This is a graph obtained by examining the values at the operating point where the specific noise Ks is minimized.

As shown in the figure, 0.4 ≦ Rs / Rt ≦ 0.6 and 20 °
If ≦ δαb ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and low noise. FIG. 94 experimentally examined the influence of the ratio of the radius Rs to the blade outer peripheral radius Rt at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss forward extension angle δαb on the maximum stress σ on the blade. Things. R in the figure
The black circle indicating the value of b / Rt is the maximum stress when the plate thickness is not locally increased from the boss portion at the blade front edge portion of the axial flow blower as the base blade. From the figure, 0.4 ≦ R
If s / Rt and 20 ° ≦ δαb, the blade strength is sufficient. Therefore, from FIGS. 93 and 94, 0.4 ≦ Rs / Rt
If ≦ 0.6 and 20 ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

This axial flow blower has a boss portion to which a blade is attached and rotated, a leading edge of the blade facing the rotating direction, a trailing edge portion of the blade facing the direction opposite to the rotating direction, and a blade outer periphery facing the boss portion. In the developed view obtained by cutting a blade of an axial blower having a blade having a circumference formed from a part with a cylindrical surface having an arbitrary radius R, and developing a cross section of the blade into a two-dimensional plane, When the shape is an arc shape and the center angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (R−R
b) / (Rt−Rb) + θb (θt: sled angle at the outer periphery of the blade, θb: sled angle at the radius Rb of the blade boss portion), and θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt <
θb, and in the above developed view, when an angle between a chord line of the blade and a straight line parallel to the rotation axis and passing through the leading edge of the blade is denoted by ξ (ξ: stagger angle), the radial distribution of ξ Ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle at blade outer periphery 部, ξ
b: stagger angle at boss radius Rb), Δt
= 55 ゜ -70 ゜, ξb = 40 ゜ -65 ゜, ξt> ξb, and the projection of the axial flow blower on a plane perpendicular to the rotation axis shows the cylindrical surface having the boss radius Rb of the blade. The chord line center point in the cross section when cut is Pb
O ′, the rotation axis is the origin O, and the point O and Pb
In a coordinate system in which the straight line connecting the point O ′ is the X axis, the chord line center point when the blade is cut by a cylindrical surface having an arbitrary radius R is PR
Assuming that the angle between the straight line PRO′-O and the X axis is δθ (δθ: advancing angle in the rotation direction) as O ′, the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt− Rb) (Rt: radius of outer periphery of blade, Rb: radius of blade boss, δθ
t: the angle between the straight line PtO'-O and the X axis), δθ
t is set to 25 to 40 °, and the value of the chord ratio T / LO defined by the chord length LO and the ratio of T to the circumferential distance (pitch) between the blades is defined as T / LO at each radial point. / LO = 1.
First, a blade shape 1O 'is formed, and a straight line 1ba connecting the origin O with the point 1baO' on the front edge of the blade at the boss radius Rb of the blade 1O 'in the projection view.
When the point when O′-O is rotated by an angle δαb between 20 and 50 ° around the origin O in the rotation direction is defined as a blade leading edge boss portion extension end point 1bb ′, the blade has an arbitrary radius R. In the developed view obtained by cutting the cylindrical surface of FIG. 1 and expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is set to the same value as the blade 10 and the warp angle θ and the stagger angle 同一. The blade chord length LbO at the boss radius Rb of the blade 1O at this time and the chord length Lb from the point 1bb to the blade trailing edge 1cb, and the difference between the chord length Lb and the blade outer periphery radius Assuming the chord length Ls at the point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the radial direction of the chord length L from the boss radius Rb to the point 1bs on the leading edge of the blade distribution L = △ Lb / (Rs- Rb) 2 × (R-Rs) 2 + Ls (Rb ≦ R ≦ R ), The blade shape is formed, so that the chord length is longer than that of the base blade 1O, a pressure increase on the blade surface is obtained, and at the time of high pressure loss, the blade front edge is closer to the boss portion. In the portion, the vertical vortex generated by the flow of the flow from the pressure surface 9 to the suction surface 8 causes the flow to flow along the blade surface, and the suction flow is blown to the outside while being guided by the vertical vortex. Disturbance of the flow on the negative pressure surface due to separation of the suction flow near the leading edge of the blade can be eliminated, noise can be reduced, and as a countermeasure when the fan is forced to rotate at high speed due to strong wind such as typhoon ,
The thickness of the blade near the boss near the blade front edge and at the connection with the boss is partially increased to avoid stress concentration due to strong wind at the root of the blade and prevent damage to the blade and boss. Since the connecting portions of the portions are formed in the shape of a wing in the form of an R shape, stress concentration can be avoided, and it is not necessary to locally increase the plate thickness.

Embodiment 12 FIG. 95 is a perspective view showing an outdoor unit of an air conditioner incorporating the axial blower according to the first to eleventh inventions. FIG. 95
FIG. 3 is an explanatory view showing an outdoor unit 18 of an air conditioner incorporating an axial blower 20 having the blade 1 according to the above-described invention. FIG. 96 is an explanatory view of a refrigeration cycle including the axial blower 20 of the present invention. In FIG. 96, the flow of the refrigerant during cooling is indicated by solid arrows, and the flow of the refrigerant during heating is indicated by broken arrows. Four-way valve 2 from compressor 21 during heating
The refrigerant passing through 3 is condensed in the indoor heat exchanger 25, the pressure is reduced by the throttle 29 through the flare 27, the extension pipe 28, and the flare valve 26, and the refrigerant evaporates in the outdoor heat exchanger 24. Return to The outdoor unit heat exchanger 24 is exposed to changes in the outside air environment, and is liable to be exposed to dew and frost. In addition, there are many more machines that suck in dust and dirt around them. If dew or frost adheres to the entire surface or a part of the outdoor heat exchanger 24, or dust or the like is slightly attached to the outdoor heat exchanger 24, the air path resistance becomes excessive and a high pressure loss state occurs. Moreover, when used as an evaporator, a high air volume is required. Even under such conditions, the axial blower having the blades of the present invention can exhibit performance in a wide range characteristically and can maintain low noise. Furthermore, since a larger air volume can be obtained as compared with the conventional apparatus, the heat exchange capacity of the heat exchanger is increased, and an efficient air conditioner can be realized.

[0102]

The axial blower according to the present invention can increase the pressure rise of the gas generated on the blade surface, and can be used even when the air path resistance, that is, the pressure loss is large. Further, even in an air path having a small resistance, the wind can be taken in from the outside by the vortex on the blade surface, so that a large air volume can be obtained. Therefore, an axial blower having a wide fan range with a small stall as a fan performance can be obtained. Further, the axial flow blower according to the present invention can control the vortex stably by the blade shape, and the vortex causes the flow of the wind to follow the blade surface, so that the turbulence of the flow on the pressure surface side of the next rotating blade is reduced. Noise can be reduced. Further, in the present invention, an axial blower having high performance and high strength and high reliability can be obtained. Also, an air conditioner that is less affected by changes in the surroundings can be obtained.

[Brief description of the drawings]

FIG. 1 is a perspective view of an axial blower according to Embodiment 1 of the present invention.

FIG. 2 is a front view of the axial blower according to the first embodiment of the present invention.

FIG. 3 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial blower according to the first embodiment of the present invention.

FIG. 4 is a sectional view taken along line YY in FIG. 3 of the axial blower according to Embodiment 1 of the present invention;

5 is a cross-sectional view of the axial blower according to the first embodiment of the present invention, taken along the line XX in FIG. 3;

FIG. 6 shows the flow coefficient φ, the specific noise Ks, and the pressure coefficient の of the axial blower according to the first embodiment of the present invention and the conventional axial blower.
Graph showing the relationship

FIG. 7 is a perspective view of an axial blower according to Embodiment 2 of the present invention.

FIG. 8 is a front view of an axial blower according to Embodiment 2 of the present invention.

FIG. 9 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial blower according to the second embodiment of the present invention.

10 is a sectional view of the axial blower according to a second embodiment of the present invention, taken along the line YY in FIG. 9;

FIG. 11 is a view showing a method of mounting the triangular flat plate 7 of the axial blower according to the second embodiment of the present invention.

FIG. 12 is a cross-sectional view of the axial blower according to the second embodiment of the present invention, taken along line XX in FIG. 9;

FIG. 13 is a ratio Rs of an arbitrary radius Rs at a point 1bs on the leading edge of the triangular flat plate 7 to the blade outer radius Rt when the rotation angle β of the axial blower according to the second embodiment of the present invention is constant. Graph of minimum specific noise against / Rt

FIG. 14 is a graph of the minimum specific noise with respect to the rotation angle β when determining the apex of the boss radius Rb of the triangular flat plate 7 at an arbitrary radius Rs / Rt = constant of the axial blower according to the second embodiment of the present invention.

FIG. 15 shows a ratio R of an arbitrary radius Rs at a point 1bs on the leading edge of the blade, which is the vertex of the triangular plate 7, to the blade outer radius Rt of the axial flow fan according to the second embodiment of the present invention.
s / Rt and the minimum specific noise Ksmi with respect to the rotation angle β when determining the vertex at the boss radius Rb of the triangular plate 7
graph of n

FIG. 16 is a perspective view of an axial blower according to a third embodiment of the present invention.

FIG. 17 is a front view of an axial blower according to a third embodiment of the present invention.

FIG. 18 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial blower according to the third embodiment of the present invention.

FIG. 19 is a sectional view taken along line XX of FIG. 18 of the axial blower according to Embodiment 3 of the present invention.

FIG. 20 shows a ratio Rs of an arbitrary radius Rs at a point 1bs on the leading edge of the triangular flat plate 7 to a blade outer radius Rt at a constant rotation angle β of the axial flow fan according to the third embodiment of the present invention. Graph of minimum specific noise against / Rt

FIG. 21 is a graph of the minimum specific noise with respect to the rotation angle β when determining the apex of the boss radius Rb of the triangular flat plate 7 at an arbitrary radius Rs / Rt = constant of the axial blower according to the third embodiment of the present invention.

FIG. 22 is a ratio R of an arbitrary radius Rs at a point 1bs on the leading edge of the blade, which is the vertex of the triangular plate 7, to the blade outer radius Rt of the axial flow fan according to the third embodiment of the present invention.
Graph of minimum specific noise with respect to rotation angle β when determining s / Rt and vertex at boss radius Rb of triangular plate 7

FIG. 23 is a perspective view of an axial blower according to Embodiment 4 of the present invention.

FIG. 24 is a front view of an axial blower according to a fourth embodiment of the present invention.

FIG. 25 is a sectional view taken along line AA in FIG. 24 of the axial blower according to Embodiment 4 of the present invention;

FIG. 26 is a diagram showing frequency characteristics of the axial blower according to the fourth embodiment of the present invention and a conventional axial blower.

FIG. 27 is a perspective view of an axial blower according to Embodiment 5 of the present invention.

FIG. 28 is a front view of an axial blower according to Embodiment 5 of the present invention.

FIG. 29 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial blower according to the fifth embodiment of the present invention.

30 is a sectional view taken along line XX in FIG. 29 of the axial blower according to Embodiment 5 of the present invention.

FIG. 31 is a perspective view showing a flow on a negative pressure surface of an axial blower according to a fifth embodiment of the present invention.

FIG. 32 is a graph showing a relationship between a flow coefficient φ, a specific noise Ks, and a pressure coefficient の of an axial blower according to a fourth embodiment of the present invention and a conventional axial blower.

FIG. 33 is a perspective view of an axial blower according to Embodiment 6 of the present invention.

FIG. 34 is a front view of an axial blower according to Embodiment 6 of the present invention.

FIG. 35 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to the sixth embodiment of the present invention.

FIG. 36 is a sectional view taken along line XX of FIG. 35 of the axial blower according to Embodiment 6 of the present invention;

FIG. 37 shows the ratio Rs / of the arbitrary radius Rs at point 1bs on the leading edge of the blade to the radius Rt of the blade outer periphery at a fixed rotation angle β of the axial flow blower according to the sixth embodiment of the present invention.
Graph of minimum specific noise against Rt

FIG. 38 is a graph of the minimum specific noise with respect to the rotation angle β at an arbitrary radius Rs = constant of the axial flow fan according to the sixth embodiment of the present invention.

FIG. 39 is a diagram illustrating a ratio Rs / of an arbitrary radius Rs to a blade outer radius Rt of an axial blower according to a sixth embodiment of the present invention.
Graph of minimum specific noise with respect to Rt and rotation angle β

FIG. 40 is a perspective view of an axial blower according to a seventh embodiment of the present invention.

FIG. 41 is a front view of an axial blower according to a seventh embodiment of the present invention.

FIG. 42 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to the seventh embodiment of the present invention.

FIG. 43 is a sectional view taken along line AA in FIG. 42 of the axial blower according to Embodiment 7 of the present invention;

FIG. 44 is a perspective view showing the flow on the negative pressure surface of the axial blower according to the seventh embodiment of the present invention.

FIG. 45 is a graph of the minimum specific noise with respect to the radius RR of the corner R of the connection portion between the boss portion near the blade front edge and the boss portion with respect to the blade outer peripheral portion Rt of the axial blower according to the seventh embodiment of the present invention.

FIG. 46 is a graph of the maximum stress σ applied to the axial flow fan according to the seventh embodiment of the present invention, with respect to the radius RR of the R-shaped portion of the connection between the blade front edge and the boss with respect to the blade outer peripheral portion Rt of the axial blower.

FIG. 47 is a perspective view of an axial blower according to an eighth embodiment of the present invention.

FIG. 48 is a front view of an axial blower according to an eighth embodiment of the present invention.

FIG. 49 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to the eighth embodiment of the present invention.

50 shows the boss radius R of the blade of FIG. 49 according to the invention.
(b) A developed view obtained by cutting the cylindrical surface and expanding the cross section into a two-dimensional plane

FIG. 51 is a view showing a state of a stable longitudinal vortex and flow in the XX section in FIG. 49 according to the present invention;

FIG. 52 is a perspective view showing the flow on the negative pressure surface of the axial blower according to the eighth embodiment of the present invention.

FIG. 53 is a diagram showing the flow on the blade negative pressure surface when the blade front edge boss portion advance extension angle δαb of the axial flow blower according to the eighth embodiment of the present invention is large.

54. Minimum specific noise with respect to the blade front edge boss forward extension angle δαb at a constant radius Rs at the blade front edge boss extension start point 1bs on the blade front edge of the blade of the axial blower according to Embodiment 8 of the present invention. Graph of

FIG. 55: Extension start point 1 of blade leading edge boss relative to blade outer peripheral radius Rt when blade leading edge boss forward extension angle δαb = constant at axial flow blower according to embodiment 8 of the present invention
graph of the minimum specific noise with respect to the ratio Rs / Rt to the radius Rs in bs

FIG. 56: A blade leading edge boss portion advance extension angle δαb and a blade outer peripheral radius Rt of the axial flow fan according to the eighth embodiment of the present invention.
Of minimum specific noise to ratio Rs / Rt with radius Rs at blade leading edge boss extension start point 1bs

FIG. 57: A blade leading edge boss portion advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow blower according to an eighth embodiment of the present invention.
Of the maximum stress σ applied to the blade against the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to

FIG. 58 is a perspective view of an axial blower according to a ninth embodiment of the present invention.

FIG. 59 is a front view of an axial blower according to a ninth embodiment of the present invention.

FIG. 60 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to the ninth embodiment of the present invention.

61 shows the boss radius R of the blade of FIG. 60 according to the invention.
(b) A developed view obtained by cutting the cylindrical surface and expanding the cross section into a two-dimensional plane

FIG. 62 is a view showing the flow in the XX section in FIG. 60 of the axial blower according to the ninth embodiment of the present invention;

FIG. 63 is a perspective view showing a flow on a negative pressure surface of an axial blower according to a ninth embodiment of the present invention.

FIG. 64 is a view showing the flow on the negative pressure surface when the blade leading edge boss portion advance extension angle δαb in the view corresponding to FIG. 61 of the axial flow blower according to the ninth embodiment of the invention is too large.

FIG. 65 is an all-round development diagram obtained by cutting the entire circumference of the axial-flow blower with a cylindrical surface having an arbitrary radius R in FIG. 60 of the axial-flow blower according to the ninth embodiment of the invention, and developing the cross section into a two-dimensional plane;

FIG. 66 shows the relationship between the flow coefficient φ, the specific noise Ks, and the pressure coefficient の of the axial blower according to the ninth embodiment of the present invention and the axial blower having the blade serving as the base of the blade of the axial flow fan of the ninth embodiment. Figure

FIG. 67: Minimum specific noise with respect to a blade leading edge boss forward extension angle δαb at a constant radius Rs at a blade leading edge boss extending start point 1bs on the blade leading edge of the axial flow blower according to the ninth embodiment of the present invention. Graph of

FIG. 68: Extension start point 1 of the blade front edge boss portion with respect to the blade outer peripheral portion radius Rt when the blade front edge boss portion advance extension angle δαb = constant at the axial flow blower according to the ninth embodiment of the present invention.
graph of the minimum specific noise with respect to the ratio Rs / Rt to the radius Rs in bs

FIG. 69 is a blade leading edge boss advancing extension angle δαb and a blade outer peripheral radius Rt of an axial blower according to a ninth embodiment of the present invention.
Of minimum specific noise to ratio Rs / Rt with radius Rs at blade leading edge boss extension start point 1bs

FIG. 70: A blade leading edge boss forward extension angle δαb and a blade outer peripheral radius Rt of an axial blower according to a ninth embodiment of the present invention.
Of the maximum stress σ applied to the blade against the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to

FIG. 71 is a perspective view of an axial blower according to a tenth embodiment of the present invention.

FIG. 72 is a front view of an axial blower according to a tenth embodiment of the present invention.

FIG. 73 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to the tenth embodiment of the present invention.

74 is an exploded view obtained by cutting the blade of the axial flow blower according to the tenth embodiment of the present invention with a cylindrical surface having a boss radius Rb, and developing the cross section into a two-dimensional plane. FIG.

FIG. 75 is a view showing a flow in an XX section of FIG. 73 of the axial blower according to the tenth embodiment of the present invention;

FIG. 76 is a perspective view showing the flow on the negative pressure surface of the axial blower according to the tenth embodiment of the present invention.

FIG. 77 is a diagram showing the flow on the blade negative pressure surface when the blade front edge boss portion advance extension angle δαb of the axial flow blower according to the tenth embodiment of the present invention is large.

FIG. 78: Minimum specific noise with respect to a blade leading edge boss forward extension angle δαb at a constant radius Rs at a blade leading edge boss extending start point 1bs on the blade leading edge of the axial flow fan according to Embodiment 10 of the present invention. Graph of

FIG. 79: When the blade front edge boss portion advance extension angle δαb = constant when the axial flow blower according to the tenth embodiment of the present invention is constant.
Graph of the minimum specific noise with respect to the ratio Rs / Rt of the blade outer edge radius Rt to the ratio of the radius Rs at the blade leading edge boss portion extension start point 1bs to the radius Rt.

FIG. 80: A blade leading edge boss advancing extension angle δαb and a blade outer peripheral radius R of an axial blower according to embodiment 10 of the present invention.
The graph of the minimum specific noise with respect to the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to t

FIG. 81: A blade leading edge boss portion advance extension angle δαb and a blade outer peripheral radius R of an axial flow blower according to embodiment 10 of the present invention.
Graph of the maximum stress σ applied to the blade against the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to t

FIG. 82 is a perspective view of an axial blower according to Embodiment 11 of the present invention;

FIG. 83 is a front view of an axial blower according to Embodiment 11 of the present invention;

FIG. 84 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the axial blower according to Embodiment 11 of the present invention.

FIG. 85 is an exploded view obtained by cutting a blade having a radius Rb of a boss portion of a blade of an axial blower according to an eleventh embodiment of the present invention and developing the cross section into a two-dimensional plane;

86 is a view showing the flow in the Y-Y section in FIG. 84 of the axial blower according to Embodiment 11 of the present invention.

FIG. 87 is a perspective view showing the flow on the negative pressure surface of the axial blower according to Embodiment 11 of the present invention.

FIG. 88 shows the flow on the suction surface when the blade front edge boss portion advance extension angle δαb in the view corresponding to FIG. 85 of the axial flow blower according to Embodiment 11 of the present invention is too large.

89 is an all-round developed view obtained by cutting the entire circumference of the axial blower with a cylindrical surface having an arbitrary radius R in FIG. 84 of the axial blower according to Embodiment 11 of the present invention, and developing the cross section into a two-dimensional plane.

FIG. 90 shows the flow coefficient φ, the specific noise Ks, and the pressure coefficient の of the axial flow fan according to the eleventh embodiment and the axial flow fan having the blades serving as the bases of the blades of the axial flow fan of the eleventh embodiment.
Diagram showing the relationship

FIG. 91 is a minimum specific noise with respect to a blade leading edge boss forward extension angle δαb at a constant radius Rs at a blade leading edge boss extending start point 1bs on the blade leading edge of the axial flow blower according to Embodiment 11 of the present invention; Graph of

FIG. 92: When the blade front edge boss forward extension angle δαb of the axial flow blower according to the eleventh embodiment of the present invention is constant,
Graph of the minimum specific noise with respect to the ratio Rs / Rt of the blade outer edge radius Rt to the ratio of the radius Rs at the blade leading edge boss portion extension start point 1bs to the radius Rt.

93. A blade leading edge boss portion advance extension angle δαb and a blade outer peripheral radius R of an axial flow fan according to Embodiment 11 of the present invention.
The graph of the minimum specific noise with respect to the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to t

94. A blade leading edge boss forward extension angle δαb and a blade outer peripheral radius R of an axial flow blower according to an eleventh embodiment of the present invention.
Graph of the maximum stress σ applied to the blade against the ratio Rs / Rt to the radius Rs at the blade leading edge boss portion extension start point 1bs with respect to t

FIG. 95 is a perspective view of an outdoor unit of an air conditioner incorporating one of the axial blowers according to the first to eleventh aspects of the present invention.

FIG. 96 is an explanatory view of a refrigeration cycle according to the present invention.

FIG. 97 is a perspective view showing a conventional axial blower.

FIG. 98 is a projection view when the blade is projected on a plane orthogonal to the rotation axis of the conventional axial flow blower.

FIG. 99: Chord line center point P of the blade of the conventional axial flow fan
W distribution in the radial direction and sectional view of the blade at the same position

FIG. 100 is an exploded view obtained by cutting a blade of a conventional axial flow blower on a cylindrical surface having an arbitrary radius R and developing the cross section on a two-dimensional plane.

FIG. 101 is a front view of a conventional axial blower.

FIG. 102 of a conventional axial blower according to the present invention.
Showing the flow on the blade negative pressure surface at the time of high pressure loss in the AA section in FIG.

Fig. 103 of a conventional axial blower in Fig. 97;
The figure which showed the flow on the blade front-edge part and the blade negative pressure surface in the place where a blade plate thickness is thick near the boss | hub part of the blade front-edge part in B cross section.

[Explanation of symbols]

1. Feather 10O. Base blade 1 '. Blade in projection 10O'. Base blade in projection 1a. Blade tip 1a '. Blade tip in projection 1aO'. Blade tip of base in projection 1b. Blade leading edge 1bO. Blade leading edge of base blade 1baO. Point 1b 'in the boss radius of the blade front edge of the base blade 1b'. Blade front edge 1bO 'in the projection view. Blade front edge 1baO'. Of the base blade in the projection view. Point 1c in the radius of the boss at the leading edge of the blade of the base blade . 1c. Blade trailing edge 1cO. Blade trailing edge of base blade 1cb. Point 1c 'at the boss radius on the trailing edge of the blade . The trailing edge 1cO ′. Blade trailing edge of base blade in projection view 1cb '. Point at boss radius on blade trailing edge in projection 1d. Blade outer periphery 1dO. 1d '. Blade outer periphery 1dO ′. 1. Blade outer periphery of blade serving as a base in projection view Boss part 3. Rotation axis 4. 4. Rotation direction Sled line 6. 6. Rotation axis parallel line Triangular plate cut 7 '. 7. Triangular plate in projection view Blade negative pressure surface 8N. 8. Blade suction surface of next swirling blade Blade pressure surface 9N. 9. Blade pressure surface of the next swirling blade 10. Vertical vortex generated near the boss at the blade front edge 11. Flow on blade suction surface 12. Suction flow of blade 13. Flow over blade pressure surface 14. Insertion direction of triangular plate 7 11. Insertion jig for triangular plate 7 Vortex at outer periphery of blade 17. Motor 18. Main body of air conditioner 20. Axial blower 22. Accumulator 23. Four-way valve 24. Outdoor heat exchanger 25. Indoor heat exchanger 26. Flare valve 27. Flare 29. Aperture

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuo Hironaka 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Inside Mitsubishi Electric Corporation (56) References JP-A-5-280493 (JP, A) JP-A Heisei 6-159290 (JP, A) JP-T-62-500040 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) F04C 29/18-29/38

Claims (18)

(57) [Claims] 1. A blade is attached to a rotating boss, and has a blade leading edge facing in the rotating direction, a blade trailing edge facing in a direction opposite to the rotating direction, and a blade outer periphery facing the boss, and has a periphery. And one side is arranged along the outer periphery of the boss adjacent to the blade front edge, and at least the blade front edge is arranged along the outer periphery of the boss adjacent to the blade front edge. An axial flow blower, comprising: a plate-like member having a thickness substantially equal to the thickness of the blade, which is attached to one of the portion and the boss portion and integrally formed with the blade. 2. A center O of rotation is defined as an origin O, and a radius O-1bs 'with respect to a point 1bs' on the leading edge of the blade at an arbitrary radius.
The point of intersection with the outer periphery of the boss when the is rotated by an angle β in the rotation direction is 1bb ', and the plate-like member has a substantially triangular shape passing through the 1bs' and 1bb'. The axial blower according to claim 1. 3. A center O of the rotation is defined as an origin O, and a radius O-1bs 'with respect to a point 1bs' on the leading edge of the blade at an arbitrary radius.
When the point of intersection with the outer periphery of the boss when the is rotated by an angle β in the rotation direction is 1bb ′, the other side of the plate member is disposed between the leading edge of the blade and this 1bb ′, the angle β 10
2. The axial flow blower according to claim 1, wherein the angle is selected to be from 40 to 40 degrees. 4. An axis O of rotation is defined as an origin O, a point 1bs 'on the leading edge of the blade at an arbitrary radius, a radius of the outer peripheral portion of the blade is Rt, and one side of the plate member is 1bs' of the leading edge of the blade.
2. The axial blower according to claim 1, wherein a radius O-1bs' is selected to be 40 to 75% of the blade outer peripheral radius Rt when disposed between the blade and the boss. 5. The axial blower according to claim 1, wherein the plate-like member is attached to the leading edge of the blade in close contact with the blade in a rotational direction. 6. A blade is attached to a rotating boss and has a blade leading edge facing in the rotating direction, a blade trailing edge facing in a direction opposite to the rotating direction, and a blade outer periphery facing the boss. And one side is arranged along the outer periphery of the boss portion adjacent to the blade front edge portion, and at least the blade front edge is arranged along the outer periphery of the boss portion adjacent to the blade front edge portion. A plate member having a thickness substantially equal to the thickness of the blade attached to one of the portion and the boss portion and integrally formed with the blade. Point 1b on the leading edge of the blade
s', and a radius O-1bs' between the 1bs' and the origin O
A plate-like member passing through the above 1bs' and 1bb ', with the intersection point with the outer periphery of the boss portion when the is rotated by an angle β in the rotation direction, as 1bb'.
An axial blower, wherein the fan is selected at 40 degrees and the radius O-1bs' is selected to be 40 to 75% of the blade outer radius Rt. 7. A blade is attached to a rotating boss and has a periphery formed by a blade leading edge facing in the rotating direction, a blade trailing edge facing in a direction opposite to the rotating direction, and a blade outer peripheral portion facing the boss. The center of rotation is defined as the origin O, and the radius O-1bs 'of an arbitrary radius with respect to the point 1bs' on the leading edge of the blade is rotated by an angle β in the rotation direction. And a blade shape in which a portion of the leading edge of the blade near the boss is extended in the rotation direction so as to pass through 1bs ′ and 1bb ′, and the angle β The axial flow blower, wherein is selected from 10 to 40 degrees. 8. The radius O-1bs' is defined as the blade outer radius Rt.
The axial flow blower according to claim 7, wherein 40% to 75% of the value is selected. 9. The axial flow blower according to claim 2, comprising a plurality of blades whose angle β is changed with respect to each of the blades. 10. A blade having a plurality of blades having different radii O-1bs' with respect to each of the blades.
The axial flow blower according to the item. 11. A blade shape in which a portion of the blade front edge portion extending from the boss portion in the rotation direction is connected to a tangent line at 1bs ′ and 1bb ′ by a curved line that is concave with respect to the rotation direction. 9. The axial flow blower according to claim 2, wherein the axial flow blower is formed as follows. 12. The blade leading edge portion is connected to a connecting portion between the blade leading edge portion and the boss portion with a curve having a radius of 15 to 35% of the radius of the blade outer peripheral portion so as to be concave in the rotation direction. The axial flow blower according to any one of claims 1 to 11, wherein the blade shape is formed as follows. 13. A boss portion to which a blade is attached and which rotates.
A blade front edge portion facing in the rotation direction, a blade rear edge portion facing in the opposite direction to the rotation direction, and a blade having a circumference formed by a blade outer peripheral portion facing the boss portion; Any point 1bs' of the blade and the leading edge of the blade
Boss located in the direction of rotation from the tangent to the tip of
The point 1bb 'on the side and the above point 1bs' are linearly connected.
The radius O-1bs' when the shape of the blade is the leading edge and the center of rotation is the origin O
40 to 75% of the blade outer radius Rt
Axial blower. 14. A boss portion which rotates by attaching a blade,
Blade leading edge facing in the direction of rotation, facing in the direction opposite to the direction of rotation
Trailing edge of the blade and the outer periphery of the blade facing the boss
A rotation center of rotation is defined as an origin O, and the origin O
A straight line 1bs'-O connecting the point 1bs'
The line 1bs'-O and the
At the point of intersection 1bb 'with the side surface of the boss and the point 1bs'
Connect the tangent with an arbitrary curve that is concave in the direction of rotation.
A straight line 1baO'-O connecting the origin O to the point 1baO 'on the blade front edge of the root of the blade, with the center of rotation being the origin O.
Is the point 1b of the boss portion radius Rb when rotated by an angle δαb, which is a question of 20 to 50 ° in the rotation direction about the origin O as a center.
The shape of the point 1bs 'on the leading edge of the blade having b' and a radius Rs of 40 to 70% of the radius of the outer peripheral portion of the blade is the boss radius Rb of the blade with respect to the leading edge of the blade. Point 1 on the blade front edge of boss radius Rb when rotated in the rotation direction by the angle δαb from point 1ba ′ on the blade front edge
A straight line 1bc'- connecting the point 1bc 'of the radius Rc of the boss portion radius Rb to the radius Rs existing in the region of bb' and the origin O.
The radial distribution of δα indicating the angle between O and the straight line 1ba′-O is given by δα = (δαb / (Rb−Rs) ² ) × (R−Rs) ² (Rb ≦ R ≦ Rs) An axial blower characterized in that the blade front edge of the portion closer to the boss portion is extended in the rotation direction from point 1bs' on the blade front edge so as to be continuous with the blade front edge to form a blade shape. 15. A boss portion to which a blade is attached and which rotates.
Blade leading edge facing in the direction of rotation, facing in the direction opposite to the direction of rotation
Trailing edge of the blade and the outer periphery of the blade facing the boss
A rotation center of rotation is defined as an origin O, and the origin O
A straight line 1bs'-O connecting the point 1bs'
The line 1bs'-O and the
Tangent line at intersection 1bb 'and point 1bs' with boss side surface
With an arbitrary curve that is concave with respect to the direction of rotation.
A straight line 1baO'-O connecting the origin O with the point 1baO 'on the blade front edge in the boss radius Rb of the blade 1O' of the base as the root front edge and the rotation axis center as the origin O, When the point when rotated by an angle δαb between 20 and 50 ° in the rotation direction about the origin O is defined as the blade front edge boss extension end point 1bb ′,
In a developed view obtained by cutting the blade at a cylindrical surface having an arbitrary radius R and expanding the cross section into a two-dimensional plane, the blade 10
The boss radius R while maintaining the same sled angle θ and stagger angle ε
b, the chord length LbO at the boss radius Rb of the blade 1O and the chord length Lb from the point 1bb to the blade rear edge 1cb, and the difference between the chord length LbO at this point and Let ΔLb be the chord length Ls at point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the radius of the outer periphery of the blade, from the radius Rb of the boss to point 1bs on the leading edge of the blade. A radial distribution of the chord length L of L = Lb / (Rs-Rb) ² × (R-Rs) ² + Ls (Rb ≦ R ≦ Rs) to form a blade shape. Flow blower. 16. A boss portion which rotates by attaching a blade,
Blade leading edge facing in the direction of rotation, facing in the direction opposite to the direction of rotation
Trailing edge of the blade and the outer periphery of the blade facing the boss
A rotation center of rotation is defined as an origin O, and the origin O
A straight line 1bs'-O connecting the point 1bs'
The line 1bs'-O and the
Tangent line at intersection 1bb 'and point 1bs' with boss side surface
With an arbitrary curve that is concave with respect to the direction of rotation.
In the developed view obtained by cutting the blade of the axial blower with a cylindrical surface having an arbitrary radius R and developing the cross section into a two-dimensional plane,
If the shape of the warp line in the blade cross section is an arc shape and the central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt-θb) × (R
−Rb) / (Rt−Rb) + θb (θt: sled angle at the outer periphery of the blade, θb: sled angle at the blade boss radius Rb)
Θt = 25 ° to 35 °, θb = 30 ° to 55
In the above development, the angle between the chord line of the hagi and a straight line parallel to the rotation axis and passing through the front edge of the blade is ε (ε:
Stagger angle), the radial distribution of ε is given by ε =
(Εt−εb) × (R−Rb) / (Rt−Rb) + εb
(Εt: bite angle ε at the outer periphery of the blade, εb = bite angle at boss radius Rb), εt = 55 ° to 7
0 °, εb = 40 ° to 65 °, εt> εb. Further, the chord length L, the chord ratio T / L defined by the ratio to the circumferential distance (pitch) T between the blades, T / L, The value is set to T / L = 1.1 to 2.0 at each radial point, and the projection of the axial flow blower on a plane perpendicular to the rotation axis indicates the cylindrical surface of the boss radius Rb of the blade. In the coordinate system in which the chord line center point in the cross section at the time of cutting is Pb ′, the rotation axis is the origin O, and a straight line connecting the point O and the point Pb ′ is the X axis, the blade has an arbitrary radius R. The center point of the chord line when cut along the cylindrical surface is PR ′, and the angle between the straight line PR′-O and the X axis is δθ (δ
When θ is the advancing angle in the rotation direction, the radial distribution of δθ is δθ = δθt × (R-Rb) / (Rt-Rb) (Rt: radius of outer periphery of blade, Rb: radius of blade boss, δθ
t: the angle between the straight line Pt′-O and the X axis), and δθt
Is set to 25 to 40 °, a blade shape is first formed, and a straight line 1ba′-O connecting the point 1ba ′ on the blade front edge portion of the root of the blade at this time and the origin O is rotated around the origin O. To 2
The point 1bb ′ of the boss radius Rb when rotated by an angle δαb between 0 and 50 ° and the radius of the outer periphery of the blade 40 to 70
% From the point 1ba 'on the leading edge of the blade, which is the boss radius Rb of the blade, with respect to the leading edge of the blade, with respect to the leading edge of the blade. The boss radius R existing between points 1bb 'on the blade leading edge at the boss radius Rb when rotated in the rotation direction by the angle δαb
The radial distribution of δα indicating the angle formed between the straight line 1bc′-O and the straight line 1ba′-O connecting the point 1bc ′ of the radius Rc and the origin O between b and the radius Rs is represented by δα = (δαb / (Rb-1 Rs) ² ) × (R-Rs) ² (Rb ≦ R ≦ Rs), and rotate the leading edge of the blade closer to the boss from the point 1bs ′ on the leading edge of the blade so as to be continuous with the blade. An axial blower characterized by extending in the direction and forming a blade shape. 17. A boss portion which rotates by attaching a blade,
Blade leading edge facing in the direction of rotation, facing in the direction opposite to the direction of rotation
Trailing edge of the blade and the outer periphery of the blade facing the boss
A rotation center of rotation is defined as an origin O, and the origin O
A straight line 1bs'-O connecting the point 1bs'
The line 1bs'-O and the
Tangent line at intersection 1bb 'and point 1bs' with boss side surface
With an arbitrary curve that is concave with respect to the direction of rotation.
In the developed view obtained by cutting the blade of the axial blower with a cylindrical surface having an arbitrary radius R and developing the cross section into a two-dimensional plane,
If the shape of the warp line in the blade cross section is an arc shape and the central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt-θb) × (R
−Rb) / (Rt−Rb) + θb (θt: sled angle at the outer periphery of the blade, θb: sled angle at the blade boss radius Rb)
Θt = 25 ° to 35 °, θb = 30 ° to 55
Θ, θt <θb, and in the above developed view, the angle formed between the chord line of the blade and a straight line parallel to the rotation axis and passing through the leading edge of the blade is ε (ε:
Stagger angle), the radial distribution of ε is given by ε =
(Εt−εb) × (R−Rb) / (Rt−Rb) + εb
(Εt: stagger angle ε at blade outer periphery, εb: stagger angle at boss radius Rb), and εt = 55 ° to 7
0 °, εb = 40 ° to 65 °, εt> εb, and in an engraved view in which the axial flow blower is projected on a plane perpendicular to the rotation axis, the blade is cut by a cylindrical surface having a boss radius Rb of the blade. In the coordinate system in which the chord line center point in the cross section is PbO ', the rotation axis is the origin O, and a straight line connecting the point O and the PbO' point is the X axis, the blade is a cylindrical surface having an arbitrary radius R. Assuming that the chord line center point at the time of cutting is PRO ′, the angle between the straight line PRO′-O and the X axis is δθ.
When (δθ: rotational angle advancing angle), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt−Rb) (Rt: radius of outer periphery of blade, Rb: radius of blade boss, δθ
t: the angle between the straight line PtO'-O and the X axis), δθ
t is 25-40 °, chord length LO, circumferential distance (pitch) between blades
The value of the chord ratio T / LO defined by the ratio of T to T / LO is set to T / LO = 1.1 to 2.0 at each radial point to first form a blade shape 1O ′. A straight line 1baO'-O connecting the point 1baO 'on the leading edge of the blade at the boss radius Rb of the blade 1O' and the origin O is rotated by an angle δαb between 20 and 50 ° about the origin O. When the point at which the blade is extended is defined as a blade leading edge boss portion extension end point 1bb ', the blade is cut by a cylindrical surface having an arbitrary radius R, and the cross-section thereof is developed into a two-dimensional plane. Warp angle θ, stagger angle ε
Is the same, the chord at the boss radius Rb is changed to the point 1b.
b, and the boss radius R of the blade 10 at this time is
b at chord length LbO and point 1bb to blade trailing edge 1
Assuming that the chord length Lb up to cb, the difference is ΔLb, and the chord length Ls at the point 1bs on the leading edge of the blade at a radius Rs of 40 to 60% of the outer radius of the blade, the boss portion radius Rb And the radial distribution of the chord length L from the point to the point 1 bs on the blade leading edge is given by L = Lb / (Rs−Rb) ² × (R−Rs) ² + Ls (Rb ≦ R ≦ Rs) An axial blower characterized by having a blade shape. 18. An air conditioner using the axial blower according to any one of claims 1 to 17.