JPH0968199A - Axial blower and air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an axial blower to broaden particularly its aerodynamic performance to a limit, relating to the axial blower used in a ventilating fan, air conditioner, etc. SOLUTION: This axial blower is provided with a boss part 2 rotated by mounting a blade 1 and the blade constituting the periphery from a blade leading edge part facing the direction of rotation, from a blade trailing edge part facing an opposite direction of rotation and from a blade peripheral part opposed to the boss part. In a projection drawing projecting the axial blower to a plane orthogonal to a rotary shaft of axial blower the rotary shaft serves as an origin O, and a straight line O-1bs' connecting the origin O to an arbitrary point 1bs' on the blade leading edge part is rotated in the direction of rotation with the origin O serving as the center. A blade shape is formed by connecting an intersection 1bb', between this straight line O-1bs' and a boss part side surface which is a boss part radius, and a tangent in the point 1bs' by an arbitrary curve such as being a hollow relating to the direction of rotation, so as to provide a blade leading edge part.

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 domestic use, industrial use, etc., and more particularly to an axial blower capable of reducing aerodynamic noise to an extremely low level. is there.

[0002]

Blowers are widely used for air conditioners, ventilation fans and the like, and it is very important for society to reduce the noise generated from the impeller as much as possible. Among the conventional techniques, Japanese Patent Publication No. 2-2
As disclosed in Japanese Laid-Open Patent Publication No. 000, this was done by clarifying the parameters that determine the three-dimensional shape of the impeller and optimizing the shape. FIG. 97 is a perspective view showing a conventional impeller disclosed in Japanese Patent Publication No. 2000-2000. In the figure, 1 is a blade of an impeller, 1a is a blade tip portion, 1b is a blade leading edge portion, 1c is a blade trailing edge portion, 1d is a blade outer peripheral portion, 2 is a boss portion for attaching the blade, 3 is a rotating shaft, 4 is a It is the direction of rotation.

FIG. 98 is a projection view of the impeller projected on a plane orthogonal to the rotation axis 3, where 1'is a blade in the plan view and 1a 'is a tip of the blade in the plan view.
1b 'is a blade leading edge portion in the plan view, 1c' is a blade trailing edge portion in the plan view, and 1d 'is a blade outer peripheral portion in the plan view. Further, FIG. 100 shows that from the wing chord line center point Pb ′ in FIG. 99 to the outer peripheral chord line center point Pt ′.
For the locus Pb'-PR'-Pt 'in the radial direction up to, the blade chord line center point PR at an arbitrary radius R is set to the plane OX.
The radial direction distribution of the chord line center point PR, which is rotationally projected on the surface with the radius R, and the cross section of the blade 1 at the same position are shown.
Further, FIG. 100 is a development view obtained by cutting the blade 1 with a cylindrical surface having a radius R and developing the cross section into a two-dimensional plane when the blade surface is formed with the chord battle center point PR as a relative origin. 5 is a warp 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. In the projection plane when the impeller is projected on the plane orthogonal to the rotation axis in FIG. 98, the chord line center point in the cross section when the boss portion of the blade is cut by the cylindrical surface of the radius Rb is Pb ′, and In the coordinate system with the axis of rotation as the origin O and the straight line connecting the point O and the point Pb ′ as the X axis, the blade chord line center point when the blade is cut by the cylindrical surface of radius R is PR ′, As a straight line Pb ',
The angle formed by the straight line Pb′-O and the X axis is δθ (δθ:
(Advancing angle in the rotation direction), the radial distribution of δθ is δ
θ = δθt × (R−Rb) / (Rt−Rb) (Rt: blade tip radius, Rb: blade boss radius, δθt: straight line P
R'-O and the X axis), δθt = 40 ° to 50 °, and in FIG. 98, in a cross section when the impeller is cut along a cylindrical surface having a radius R centered on the rotation axis. When the distance between the chord line center point PR and the plane SC passing through the chord line center point Pb in the cross section when the boss portion of the blade is cut by the cylindrical surface of the radius Rb and orthogonal to the rotation axis is Ls , In the coordinate system in which the suction side of the airflow is in the positive direction, the chord line center point PR is always positioned in the positive direction with respect to the SC plane, and δZ = tan−1 (LS / (R−Rb))
The value of δZ that can be expressed by (δZ: Suction direction forward tilt angle) is δZ
= 12.5 ° to 32.5 °,

Further, in FIG. 100, in a development view obtained by cutting the blade with a cylindrical surface of radius R and developing the cross section into a two-dimensional plane, the shape of the warp line in the blade cross section is an arc shape, and the arc When the central angle for forming a shape is θ (θ: warp angle), the radial distribution of θ is θ
= (Θt−θb) × (R−Rb) / (Rt−Rb) + θ
b (θt: warp angle at blade tip, θb: warp angle at blade boss), θt = 20 ° to 30 °, θb = 27 ° to 37 °, θt <θb, and blade mounting The position is parallel to the chord line 1b-1c and the rotation axis 3, and the blade front edge portion 1
When the angle formed by the straight line 6 passing through b is the stagger angle ξ, the radial distribution of ξ is ξ = (ξt−ξb) × (R−
Rb) / (Rt−Rb) + ξb (ξt: stagger angle at blade tip, ξb: stagger angle at blade boss), and ξt = 62 ° to 72 °, ξb = 53 ° to 63 °, ξt>
Further, L in FIG. 100 is the chord length, and the blade size is limited by the node 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 using such an impeller having a three-dimensional curved surface, the development of the boundary layer on the impeller surface is suppressed and the state of the discharge vortex is changed, so that the axial blower with a considerably low noise over a relatively wide operating region. It was.

[0006]

The conventional axial-flow blower has the characteristics of low noise as described above, but in the vicinity of the operating point where the air volume is large and the wind pressure is not so high, as shown in FIG. In the vicinity of the edge boss, the air sucked collides with the suction surface side of the blade, causing turbulence in the flow on the suction 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 etc. adheres to the suction port side and it becomes difficult to suction, a flow separation phenomenon occurs near the blade leading edge on the blade negative pressure surface, causing large turbulence. Since the included flow flows on the suction surface of the blade, there is a problem that a large pressure fluctuation occurs and noise increases.

Further, the blade of the conventional axial blower is strong in terms of strength.
There was a tendency for stress concentration to escape by partially thickening the plate thickness near the blade leading edge boss. Therefore, the blade leading edge becomes locally thick, and the flow collides with the thick blade leading edge boss, and the resulting turbulence gives rise to turbulence in the flow on the blade surface, resulting in pressure fluctuations. There was a tendency for the noise to worsen with an increase. The present invention has been made to solve the above-described problems, and prevents the suction flow from colliding with the blade leading edge boss portion, and also has a high static pressure, high performance, low noise, and high strength. The purpose is to obtain a sufficient axial flow fan. Still another object of the present invention is to obtain an air conditioner with low noise.

[0008]

The axial blower according to the first aspect of the present invention is attached to a rotating boss and has a blade leading edge facing the rotational direction and a blade trailing edge facing the opposite direction. , And a blade whose periphery is formed by the outer peripheral portion of the blade facing the boss portion, and one side along the outer periphery of the boss portion adjacent to the front edge portion of the blade and the other side along the outer periphery of the boss portion of the blade front edge portion. And a plate-shaped member having a thickness substantially equal to the thickness of the blade, which is arranged integrally with the blade and is attached to at least one of the leading edge portion and the boss portion of the blade. .

Further, in the axial blower according to the second aspect of the present invention, the center of rotation is the origin O, and the radius O-1bs 'with the point 1bs' on the blade leading edge portion at an arbitrary radius is an angle β in the rotation direction.
An intersection with the outer periphery of the boss portion when rotated is 1bb ', and the plate-shaped member has a substantially triangular shape so as to pass through 1bs' and 1bb'. Further, in the axial blower according to the third aspect of the present invention, the origin is O at the axis of rotation, and the radius O- with the point 1bs' on the blade leading edge portion at an arbitrary radius.
Let 1bb 'be the intersection with the outer circumference of the boss portion when 1bs' is rotated by an angle β in the rotation direction, and the plate-shaped member is the above 1b.
When placed between s'and the above 1bb ', the angle β is set to 1
It is selected from 0 to 40 degrees.

In the axial blower according to the fourth aspect of the present invention, the center of rotation is the origin O, the point 1bs' on the blade leading edge portion at an arbitrary radius is set, and the blade outer peripheral radius is set to Rt. The radius O-1bs 'is selected to be 40 to 75% of the blade outer peripheral radius Rt when one side is arranged between 1bs' of the blade leading edge portion and the boss portion. Further, in the axial blower according to the fifth aspect of the present invention, the plate-shaped member is attached to the blade leading edge portion in close contact with each other in the rotation direction.

The axial blower according to the sixth aspect of the present invention is attached to a rotating boss portion, and has a blade front edge portion facing the rotational direction, a blade rear edge portion facing the opposite direction, and a boss portion. And a blade whose periphery is defined by the outer peripheral portion of the blade, and one side of which is arranged along the boss portion of the blade leading edge portion, and the other side of which is arranged along the outer periphery of the boss portion adjacent to the blade leading edge portion. At the same time, it is a plate-shaped member that is attached to at least one of the blade leading edge portion or the boss portion and is integrally formed with the blade, and has a thickness that is substantially the same as the blade thickness, with the axis O of rotation as the origin O. Point 1 on the blade leading edge at any radius
bs', and the radius O-1bs' between the bs' and the origin O
The angle β is selected to be 10 to 40 degrees, with a plate-shaped member that passes through 1bs ′ and 1bb ′ with 1 bb ′ as the intersection with the outer circumference of the boss portion when the is rotated by the angle β in the rotation direction. Then, set the radius O-1bs' to 40 to 7 of the blade outer peripheral radius Rt.
It was selected to be 5%.

In the axial blower according to the seventh aspect of the invention, the blade is attached to the rotating boss portion and faces the rotation direction, the blade front edge portion, the blade rear edge portion facing the opposite direction, and the boss portion. The origin of the blade is the outer periphery of the blade and the center of rotation is the origin O, and the radius O-1bs 'with the point 1bs' on the blade leading edge at an arbitrary radius is rotated by the angle β in the rotation direction. The intersection with the outer circumference of the boss when it is moved is 1b
As b ', a blade shape in which a portion near the boss portion of the blade front edge is extended in the rotational direction in a shape that passes through 1bs' and 1bb', and the angle β is selected to be 10 to 40 degrees. Is. The axial blower according to the eighth invention has a radius O
-1bs' is selected as 40 to 75% of the outer peripheral radius Rt of the blade. The axial blower according to the ninth invention is
It has a plurality of blades whose angle β is changed for each blade. The axial blower according to the tenth invention is
It has a plurality of blades whose radius O-1bs' is changed for each blade.

Also, in the axial blower according to the eleventh aspect of the present invention, the blade shape obtained by extending a portion from the boss portion of the blade front edge portion in the rotational direction is formed such that the tangent lines at 1bs 'and 1bb' are concave with respect to the rotational direction. It is formed so as to form the front edge of the knotting blade with such a curved line. Further, the axial blower according to the twelfth aspect of the invention is such that the connecting portion between the blade leading edge portion and the boss portion is concave with respect to the rotational direction having a radius of 15 to 35% of the radius of the blade outer peripheral portion. The blade shape is formed so that it is connected by a curved line to form the blade leading edge portion.

In the axial blower according to the thirteenth aspect of the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and A vane whose circumference is composed of the vane outer peripheral portion facing the boss portion, and an origin O that is the axis of rotation, and a straight line 1bs'-O that connects the origin O and an arbitrary point 1bs' on the vane leading edge portion. Straight line 1bs' when rotated in the direction of rotation around O
-Intersection point 1bb 'between O and the side surface of the boss, which is the radius of the boss.
And the blade shape is formed so that the tangent line at the point 1bs' is connected to the blade front edge by an arbitrary curve that is concave with respect to the rotation direction.

In the axial blower according to the fourteenth aspect of the invention, the origin O is the center of rotation, and the straight line 1baO'-O connecting the origin O with the point 1baO 'on the blade leading edge of the root of the blade.
Is rotated about the origin O by an angle δαb which is between 20 and 50 ° in the rotation direction, and the point 1b of the boss radius Rb.
Before the blade, the shape between b ′ and the point 1bs ′ on the blade leading edge having a radius Rs of 40 to 70% of the blade outer peripheral radius is the boss radius Rb of the blade with respect to the blade leading edge. The radius Rc between the boss radius Rb and the radius Rs existing between the point 1bb 'on the blade leading edge of the boss radius Rb when rotated from the point 1ba' on the edge by the angle δαb. Line 1bC'-O connecting the point 1bC 'and the origin O and the line 1b
The radial distribution of δα indicating the angle formed by a′-O is δα = (δαb / (Rb-RS) 2) × (R-RS) 2
(Rb ≦ R ≦ Rs), so that the point 1b on the blade leading edge is continuous with the blade.
The blade shape is formed by extending the blade front edge portion closer to the boss portion than s ′ in the rotation direction.

Further, in the blower according to the fifteenth aspect of the present invention, the center of rotation is set as an origin O, and a straight line connecting the origin O with the point 1baO 'on the blade leading edge portion at the boss radius Rb of the blade 1O' of the base. When 1baO'-O is rotated about the origin O in the rotation direction by an angle δαb that is between 20 and 50 ° and the blade front edge boss extension end point 1bb 'is defined, the blade has an arbitrary radius R In a development view obtained by cutting the cross section at a cylindrical surface and developing the cross section into a two-dimensional plane, the blade chord at the boss radius Rb is set to the point 1bb while the blade 1O has the same warp angle θ and stagger angle ξ. The 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 portion 1Cb, and the difference is ΔLb,
Assuming that the chord length LS at the point 1bs on the blade leading edge at a radius Rs of 40 to 60% of the blade outer peripheral radius is the boss radius R
The radial distribution of the chord length L from b to the point 1bs on the blade leading edge is L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
(Rb ≦ R ≦ Rs) to form a blade shape.

In the axial blower according to the sixteenth invention, the blade of the axial blower is cut along a cylindrical surface having an arbitrary radius R and the cross section is developed into a two-dimensional plane. When 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: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt
<Θb, and in the above developed view, when the angle formed by the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge of the blade is ξ (ξ: stagger angle), the radial direction of ξ The distribution is ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle ξ, ξ at the outer periphery of the blade
b: stagger angle at boss radius Rb), ξt
= 55 ° to 70 °, ξb = 40 ° to 65 °, ξt> ξb, and a chord ratio defined by the ratio of the chord length L and the circumferential distance (pitch) T between the blades. The value of T / L is
When T / L = 1.1 to 2.0 at each radius point and a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis, when cut by a cylindrical surface having a boss radius Rb of the blade. The center point of the chord line in the cross section of Fig. 4 is Pb ', the axis of rotation is the origin O, and the straight line connecting the point O and Pb' is the X axis, and the blade is a cylindrical surface of arbitrary radius R. Let PR ′ be the center point of the chord line when cut with
When the angle between R′-O and the X axis is δθ (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt−Rb) (Rt: Blade outer radius, Rb: Blade boss radius, δθ
t: angle formed by 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 a point 1ba ′ on the blade leading edge portion of the blade root and an origin O at this time is rotated about the origin O. To 2
A point 1bb ′ of the boss radius Rb when rotated by an angle δαb between 0 and 50 ° and a blade outer peripheral radius of 40 to 70.
The shape between points 1bs ′ on the blade leading edge having a radius Rs of% is defined from the point 1ba ′ on the blade leading edge which is the boss radius Rb of the blade with the blade leading edge as a reference. The boss radius R 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.
The radial direction distribution of δα, which represents the angle between the straight line 1bC′-O connecting the point 1bC ′ of the radius Rc between the radius b and the radius Rs and the origin O, is δα = (δαb / (Rb- RS) 2) x (R-RS) 2
(Rb ≦ R ≦ Rs), and a blade shape is formed by extending the blade front edge portion closer to the boss from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. Is.

In the axial blower according to the seventeenth aspect of the present invention, the blade of the axial blower is cut along a cylindrical surface having an arbitrary radius R, and its cross section is developed into a two-dimensional plane. When 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: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt
<Θb, and in the above developed view, when the angle formed by the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge of the blade is ξ (ξ: stagger angle), the radial direction of ξ The distribution is ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle ξ, ξ at the outer periphery of the blade
b: stagger angle at boss radius Rb), ξt
= 55 ° to 70 °, ξb = 40 ° to 65 °, ξt> ξb, and a projection view of the axial blower projected on a plane orthogonal to the rotation axis, a cylindrical surface having a boss radius Rb of the blade Let Pb be the center point of the chord line in the cross section when cut.
O ′, the rotation axis as the origin O, and the point O and Pb
In a coordinate system with the straight line connecting the O'point as the X axis, the center point of the chord line when the blade is cut along a cylindrical surface with an arbitrary radius R is PR
As O ′, when the angle between the straight line PRO′-O and the X-axis is δθ (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt− Rb) (Rt: blade outer radius, Rb: blade boss radius, δθ
t: angle formed by the straight line PtO'-O and the X-axis), and δθ
Further, t is set to 25 to 40 °, and the value of the chord chord ratio T / LO defined by the ratio of the blade chord length LO and the circumferential distance (pitch) between the blades T is T at each radius point. / LO = 1.
1 to 2.0, first, a blade shape 1O 'is formed, and in the above projection, a straight line 1ba connecting a point 1baO' on the blade leading edge portion at the boss radius Rb of the blade 1O 'and an origin O.
When the point when the O′-O is rotated about the origin O in the rotation direction by an angle δαb that is between 20 and 50 ° is taken as the blade leading edge boss extension end point 1bb ′, the blade has an arbitrary radius R In a developed view obtained by cutting the cross section into a two-dimensional plane by cutting it along the cylindrical surface of, the blade chord at the boss radius Rb is the same as that of the blade 10 and the warp angle θ and the stagger angle ξ are the same. 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 at this time, the difference being ΔLb, and the blade outer circumference radius And a chord length LS at a point 1bs on the blade leading edge 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 blade leading edge. Distribution is L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
(Rb ≦ R ≦ Rs) to form a blade shape. An air conditioner according to the 18th aspect of the invention uses the axial blower described above.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION

Example 1 An example will be described below with reference to the drawings. FIG. 1 is a perspective view showing an embodiment of the axial blower according to the present invention.
For example, it has a shape of three blades, and the operation will be described mainly for one blade 1, but the same applies to the other blades. In the figure, 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 leading edge portion, and 1d is a blade. The outer peripheral portion of the blade, 1C is a trailing edge portion of the blade, and 7 is a triangular flat plate attached from the 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.
It is the projection figure which projected. In the figure, the same symbols as those in FIG. 1 indicate the same components. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. In the figure, a flat plate 7'having almost the same thickness as the blade and having a substantially triangular shape is attached so that one side 7b 'is substantially along the circumference of the boss portion 2 and the other side 7c' is closer to the boss portion of the blade front edge portion 1b '. Then, the blade is formed so as to be integrated with the blade in the rotation direction so as to be integrated with the blade. FIG. 4 is an enlarged view in which a YY cross section obtained by cutting the triangular flat plate 7 ′ and the vicinity of the blade leading edge portion 1b ′ of FIG. 3 with a cylindrical surface having an arbitrary radius R is developed into a two-dimensional plane. In the figure, 1 is a blade of an axial blower, 7 is a triangular flat plate that is externally inserted near the boss portion of the blade front edge portion 1b, 7
c is a bonding surface between the triangular flat plate 7 and the blade front edge portion 1b, 7
Reference symbol a indicates the suction side end of the triangular flat plate 7 which is continuous with the blade front edge 1b.

By forming in this way, the triangular flat plate 7 is formed at the time of high pressure loss as shown in FIG. 5 showing the XX cross section of FIG.
The stable longitudinal vortex 10 generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 at one side 7a connected to the blade leading edge portion 1b causes the flow along the blade surface and the suction flow 12 The air is blown outside while being guided by 10. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise. FIG. 6 is a characteristic diagram obtained by experimentally determining the relationship between the pressure coefficient ψ and the specific noise Ks [dB (A)] of the conventional axial flow fan and the axial flow fan according to the embodiment of the invention described above. Is.

The flow coefficient φ, the pressure coefficient ψ, and the specific noise Ks will be described. The flow coefficient φ can be expressed as follows and is a dimensionless number. φ = Q / (π2 / 4 ・ D3 ・ (1-ν2) ・ N) Q: Air volume [m3 / min] D: Blade outer radius [m] ν: Boss ratio (boss radius / blade outer radius) N: Number of revolutions [rpm] Further, the pressure coefficient ψ is a dimensionless number of the ratio of the dynamic pressure corresponding to the blade outer peripheral speed u to the pressure increase P. ψ = 7200Ps / (ρ (πDN) 2) Ps: Static pressure [Pa] D: Blade outer radius [m] N: Rotation speed [rpm] ρ: Air density [Kg / m3] On the other hand, the specific noise Ks is It is defined like an expression. Ks = SPL-10Log (Q ・ Ps2.5) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m3 / 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, compared to the conventional case, the operating region in which the blades do not stall extends to the low air volume side and the static pressure is increased as a whole. On the other hand, the specific noise Ks can be reduced by 1 [dB (A)] at the maximum, which is low noise.

In this axial blower, a boss portion having blades attached thereto and rotating, a blade front edge portion facing in the rotation direction, a blade trailing edge portion facing in the opposite direction to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is composed of a portion, a flat plate whose thickness is almost the same as the blade thickness is approximately one side at the leading edge of the blade. Along the circumference of the boss, the other side is formed integrally with the blade so as to be attached to the front edge of the blade close to the boss, so that dust is accumulated on the suction port. At the time of high pressure loss, such as when a high pressure loss occurs, the longitudinal vortex generated by the wraparound of the flow from the pressure surface to the suction surface on one side connected to the blade leading edge of the triangular flat plate causes the flow to follow the blade surface and the suction flow Sending to the outside while 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.

Second Embodiment Another embodiment will be described below 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 shape of three blades, and the operation will be described mainly for one blade 1, but the same applies to the other blades. In the figure, 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 leading edge portion, and 1d is a blade. The outer peripheral portion of the blade, 1C is a trailing edge portion of the blade, and 7 is a triangular flat plate attached from the 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.
It is the projection figure which projected. In the figure, the same symbols as in FIG. 8 indicate the same components. Reference numeral 1'denotes a blade in the projection view, 1b 'denotes a blade front edge portion in the projection view, 1c' denotes a blade trailing edge portion in the projection view, and 1d 'denotes a blade outer peripheral portion in the projection view. In the figure, the rotation axis is the origin O, and the above O
In a coordinate system with a straight line connecting the point and the arbitrary point 1bs' on the blade leading edge 1b 'as the X axis, the straight line O-1bs' is rotated by .beta. A flat plate 7'having substantially the same thickness as the blade and having a substantially triangular shape is attached to one side 7 so as to pass through the intersection 1bb 'with the side surface and the point 1bs'.
b'almost 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 ', and is externally attached so as to be integrated with the blade in the rotation direction, and adhered. The blade shape is formed by adhering or welding with a material.

FIG. 10 is a Y-Y obtained by cutting the triangular flat plate 7'and the blade leading edge portion 1b 'shown in FIG. 9 by a cylindrical surface having an arbitrary radius R.
It is an enlarged view which expanded the cross section to a two-dimensional plane. In the figure, 1'is a blade of an axial blower, 7'is a triangular flat plate externally inserted near the boss portion of the blade leading edge 1b, and 7c 'is an adhesive surface between the triangular flat plate 7'and the blade leading edge 1b'. , 7a 'indicate the blade leading edge portion 1b' and the triangular plate suction side end portion. FIG. 11 shows an example of a method of attaching the triangular flat plate 7 to the blade front edge portion 1b. Reference numeral 14 is a direction of inserting the triangular flat plate, 15 is a three-dimensionally movable mounting jig, 1 is a blade, 2 is a boss portion, and 3 is a rotation axis. As for the method of attaching the triangular flat plate 7, first, the jig 15 is inserted into the rotary shaft, the height and angle of the blade front edge 1b to which the triangular flat plate 7 is attached are adjusted, and then the triangular flat plate 7 is brought into close contact with the blade front edge 1b. Part 7c Part 7b that is in close contact with the recess and the side surface of the boss
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, the pressure surface 9 is formed at one side 7a connected to the blade front edge portion 1b of the triangular flat plate 7 as shown in FIG. Due to the stable vertical vortex 10 generated by the wraparound of the flow from the suction surface 8 to the suction surface 8, the flow follows the vane 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, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise. In addition, the existing axial blower can be easily improved.

Here, a point 1bs on the blade leading edge 1b through which one apex of the triangular flat plate 7 passes and the straight line O-1bs.
Is rotated about the origin O and the intersection point 1b with the side surface of the boss portion 2
If the rotation angle β at the time of obtaining b is too large or too small, on the contrary, the blades are disturbed and the noise is 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 a noise characteristic when the rotation angle β = constant, for example, when the rotation angle β 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 blade outer peripheral radius Rt. This is an experimentally obtained effect. At this time, the specific noise Ks
Changes depending on the operating point, so the value at the operating point where the specific noise Ks is the minimum is plotted as the minimum specific noise Ksmin. Here, the specific noise Ks is defined by the following equation. Ks = SPL-10Log (Q ・ Ps2.5) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m3 / min] Ps: Static pressure [mmAq] As shown in the figure, the radius Rs at the position of the point 1bs on the blade leading edge 1b is 0.4 to 0.4 of the blade outer peripheral radius Rt. When the value is between 0.75 times, the value of the minimum specific noise Ksmin is small and the noise is low. Further, in the figure, Rs / Rt = 0 (on the Y-axis) shows the value of the conventional axial blower to which the flat plate is not attached,
It can be seen that the maximum noise is 1 [dB (A)] lower than the conventional value.

FIG. 14 shows a ratio Rs / indicating the position of the point 1bs.
This is an experimentally obtained effect of the rotation angle β in FIG. 9 on the noise characteristic when Rt = constant, for example, 0.6 to 0.7. 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 becomes the minimum is graphed as the minimum specific noise Ksmin. As shown in the figure, when the straight line O-1bs connecting the point 1bs on the blade leading edge portion 1b and the origin O is rotated in the fan rotation direction around the origin O, the rotation angle β is between 10 ° and 40 °. In the case of, the value of the minimum specific noise Ksmin is small and the noise is low.
Also, the value around -10 ° in the figure shows the value of the conventional axial blower without the flat plate attached, but compared with the conventional value,
It can be seen that the maximum noise is 1 [dB (A)].

FIG. 15 shows experimentally the effect of the ratio Rs / Rt between the radius Rs at the position of 1bs and the blade outer radius Rt and the rotation angle β on the noise characteristics, and the operation that minimizes the specific noise Ks. 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.

In this axial blower, a boss portion having blades attached thereto and rotating, a blade front edge portion facing in the rotation direction, a blade trailing edge portion facing in the direction opposite to the rotation direction, and a blade facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a vane whose circumference is formed from the outer peripheral portion, the thickness is almost the same as the blade thickness at the leading edge of the vane, and is substantially triangular. In the coordinate system with one side along the circumference of the boss and the axis of rotation as the origin O and the line connecting the point O and the point 1bs' on the blade leading edge at an arbitrary radius as the X axis, When O-1bs 'is rotated about the origin O in the rotation direction by an angle β, the intersection point with the boss portion having the radius Rb is 1bb', and the angle β is 10 ° to 10 °.
40 °, and the other side is 40 to 7 of the blade outer radius Rt.
Since it is shaped so as to pass through the point 1bs' on the blade leading edge portion of 5%, it is closely attached to the blade leading edge portion near the boss portion, and is integrally formed on the blade so as to be extrapolated from the rotational direction.
At the time of high pressure loss, the longitudinal vortex generated by the wraparound of the flow from the pressure surface to the suction surface at one side 7a connected to the blade front edge portion 1b of the triangular flat plate 7 causes the flow to follow the blade surface and the suction flow to be the longitudinal vortex. Of the flow on the blade negative pressure surface 8 due to separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss by being blown to the outside while being guided to
Disturbance can be eliminated, and noise can be reduced.

Third Embodiment Another embodiment will be described below with reference to the drawings. FIG. 16 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a shape of three blades, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade leading edge portion, 1d denotes a blade outer peripheral portion, and 1C denotes a blade trailing edge portion.

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 symbols as those in FIG. 17 indicate the same components. 1'is the blade in the projection, 1b '
Is a blade front edge portion in the projection view, 1c ′ is a blade trailing edge portion in the projection view, and 1d ′ is a blade outer peripheral portion in the projection view. In the figure, in the coordinate system with the rotation axis as the origin O and the straight line connecting the point O and any point 1bs' on the blade leading edge 1b 'as the X axis, the straight line O-1bs' is centered at the origin O. A straight line 1bb'-1 passing through the intersection point 1bb 'with the side surface of the boss and the point 1bs' when rotated by the angle β in the rotation direction.
so that bs 'becomes the blade leading edge 1b', 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 in this way, at the time of high pressure loss, 1bs'- which is a part of the blade leading edge 1b 'of FIG.
In FIG. 19, which is an XX cross section of 1bb ′,
By the stable vertical vortex 10 generated by the sneak of the flow from the pressure surface 9 to the suction surface 8 of s-1bb, the flow is along the vane surface, and the suction flow 12 is guided to the vertical vortex 10 and is blown to the outside. To be done. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise.

Further, unlike the case where the blade shape is formed by attaching another component as in the second embodiment, since the blade is integrally formed, the flow is disturbed by the concave portion at the joint or the convex portion due to the adhesive. It is possible to prevent the occurrence of noise and reduce noise. Here, the position of the point 1bs at the time of extending the portion 1bs'-1bb 'from the boss portion 2 of the blade leading edge portion 1b 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 at the time of determining the intersection 1bb with the side surface is too large or too small, on the contrary, the blade is disturbed and noise is 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 experimentally the influence on the noise characteristic of 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. It is a thing.
At this time, the specific noise Ks changes depending on the operating point.
The value at the operating point where the specific noise Ks is the minimum is the minimum specific noise Ks
Graphed as min. Here, the specific noise Ks is defined by the following equation. Ks = SPL-10Log (Q ・ Ps2.5) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m3 / 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 outer radius Rt of the blade.
The value of the minimum specific noise Ksmin is small and low when it is between 0.75 and 0.75 times. Further, in the figure, Rs / Rt = 0
(On the Y-axis) shows the value of the conventional axial flow fan without the flat plate attached, but it can be seen that the maximum noise is 2 [dB (A)] lower than the conventional value.

FIG. 21 shows a ratio Rs / indicating the position of the point 1bs.
It is an experimental result of the influence of the rotation angle β in FIG. 18 on the noise characteristics when Rt = 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 becomes the minimum is graphed as the minimum specific noise Ksmin. As shown in the figure, when the straight line O-1bs connecting the point 1bs on the blade leading edge 1b and the origin O is rotated in the fan rotation direction about the origin O, the rotation angle β is 1.
When it is between 0 ° and 40 °, the value of the minimum specific noise Ksmin is small and the noise is low. In addition, the value around -10 ° in the figure shows the value of the conventional axial flow fan without the flat plate attached, but it is 2 [dB (A)] low noise at maximum compared to the conventional value. I understand.

FIG. 22 experimentally examines the effect of the ratio Rs / Rt of the radius Rs at the position of 1 bs and the outer peripheral radius Rt of the blade and the rotation angle β on the noise characteristics, and the operation that minimizes the specific noise Ks. The results of graphing the values at points are shown. From FIG. 22, 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 portion that is rotated by attaching a blade, a blade front edge portion that faces in the rotation direction, a blade trailing edge portion that faces in the opposite direction to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is formed by a portion, a rotation axis O and a blade outer peripheral radius of 40 to 75 on a blade leading edge portion are included. The straight line O-1bs 'connecting with the point 1bs' having a radius of 10% is rotated about the origin O in the rotation direction by 10 to 40 °.
Between the straight line O-1bs' and the side surface of the boss portion which is the radius of the boss portion 1bb 'and 1b'.
Since s'is connected by a straight line and a blade shape is formed by extending a portion of the blade leading edge portion near the boss portion in the rotational direction, X is a part of the blade leading edge portion 1b 'during high pressure loss. In the −X cross section, the longitudinal vortex generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 causes the flow to follow the vane surface, and the suction flow is blown to the outside while being guided by the vertical vortex. 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 front edge portion 1b at the time of high pressure loss can be eliminated, and noise can be reduced.

Fourth Embodiment Another embodiment will be described below with reference to the drawings. FIG. 23 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a three-blade shape, and the operation will be described mainly for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 is a rotation axis of the blade 1, 4 is an arrow indicating a rotation direction, 1b is a blade leading edge portion, 1d is a blade outer peripheral portion, and 1C is a blade trailing edge portion.

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 symbols as those in FIG. 23 indicate the same components. 1I 'is the blade in the projection, 1bI' is the leading edge of the blade in the projection, 1cI '
Is the trailing edge of the blade in the projected view, and 1I 'is the outer peripheral portion of the blade in the projected view. Also, the subscripts II and III indicate the same of the other blades. In the drawing, the rotation axis is the origin O, and the blade outer radius Rt of 40 to 7 different from the above point O for each blade.
In the coordinate system with the X axis being the straight line connecting the point 1bs 'on the blade leading edge 1b' at the radius of 5%, the straight line O-1b
The straight line 1bb'-1bs 'passing through the point 1bs' and the intersection 1bb 'with the side surface of the boss portion when s'is rotated by the angle β in the rotation direction about the origin O becomes the blade leading edge 1b'. A blade shape is formed such that a portion of each blade near the boss portion 2 of the blade leading edge portion 1b ′ 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 portion 1b 'of FIG.
In FIG. 25 which is an AA cross section of b ′, 1bs-
A stable vertical vortex 10 generated by the wraparound of the flow from the pressure surface 9 of 1 bb to the suction surface 8 causes the flow to follow the vane surface, and the suction flow 12 is guided to the vertical vortex 10 and blown to the outside. . Therefore, as a problem in the conventional axial blower, the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG.
It is possible to eliminate the turbulence of the flow 11 on the blade negative pressure surface 8 due to the separation of, and to reduce the noise.

Further, the blade leading edges 1bI ', 1bI of each blade
Since the part is different from the boss part of I ', 1bIII',
As shown in FIG.
The rotation sound determined by [rpm] and the peak sound due to a sound that is a positive multiple of the generated frequency (NZ / 60 [Hz]) are eliminated as indicated by the broken line, and the sound at the specific frequency can be reduced.
As a result, it is possible to avoid the abnormal sound that is a problem in the product.

This axial-flow blower has a boss portion with the blades attached and rotating, a blade front edge portion facing the rotation direction, a blade trailing edge portion facing the direction opposite to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is formed by a portion, a rotation axis O and a blade outer peripheral radius of 40 to 75 on a blade leading edge portion are included. The straight line O-1bs 'connecting the point 1bs' having a radius of 10% is rotated about the origin O in the rotation direction by 10 to 40 °
The blade shape is formed by changing the intersection point 1bb 'between this straight line O-1bs' and the boss side surface, which is the radius of the boss section, for each blade within a range, At the time of loss, 1bs 'which is a part of the blade leading edge 1b'
By the stable vertical vortex 10 generated by the wraparound of the flow from the pressure surface 9 of -1bb 'to the suction surface 8, the flow is along the blade surface, and the suction flow 12 is guided to the vertical vortex 10 and is blown to the outside. As a result, turbulence of the flow 11 on the blade negative pressure surface 8 due to separation of the suction flow 12 near the blade front edge portion 1b at the time of high pressure loss can be eliminated, and noise can be reduced. In addition, since the portion of each blade that is different from the boss portion of the blade leading edge is different, the rotation noise determined by the number of blades Z and the rotation speed N [rpm] in the conventional axial blower, and the generation frequency (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, it is possible to avoid the abnormal sound that is a problem in the product.

Fifth Embodiment Another embodiment will be described below with reference to the drawings. FIG. 27 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a three-blade shape, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 is a rotation axis of the blade 1, 4 is an arrow indicating a rotation direction, 1b is a blade leading edge portion, 1d is a blade outer peripheral portion, and 1C is a blade trailing edge portion. 28 is a front view of FIG. 27.

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 symbols as in FIG. 28 indicate the same items. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. In the projection view, a straight line O-1bs ′ connecting the rotation axis O and an arbitrary point 1bs ′ on the blade front edge portion is rotated about the origin O in the rotation direction to obtain a straight line O-1b.
A blade shape is formed so that a tangent line at an intersection point 1bb ′ between s ′ and a side surface of the boss which is the radius of the boss and the tangent line at the point 1bs ′ is an arbitrary curve which is concave with respect to the rotation direction to form a blade leading edge portion. are doing.

With this structure, at the time of high pressure loss, as shown in FIG. 30 showing the XX cross section of FIG. 29, the blade pressure surface 9 to the suction surface of the blade front edge portion 1b near the boss portion. Stable vertical vortex 1 generated by wraparound flow
By 0, the flow is along the vane surface, and the suction flow is 1
2 is blown to the outside as shown in FIG. 31 while being guided by the vertical vortex 10. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise. FIG. 32 shows the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks [dB of the conventional axial flow fan and the axial flow fan according to the embodiment of the fifth invention.
It is a characteristic view which calculated | required (A)] experimentally. 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, compared with the conventional case, the operating region extends to the low air volume side and the static pressure is increased as a whole. On the other hand, the maximum specific noise Ks is 2.5 [dB
(A)] and low noise.

In this axial blower, a boss portion having blades attached thereto and rotated, a blade front edge portion facing in the rotation direction, a blade trailing edge portion facing in the direction opposite to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is composed of a portion, the rotation axis O and an arbitrary point 1b on the blade leading edge portion
When the straight line O-1bs 'connecting to s'is rotated in the rotation direction about the origin O, the intersection point 1bb' between the straight line O-1bs 'and the side surface of the boss portion, which is the radius of the boss portion, and the point 1bs' Since the blade shape is formed by connecting the tangent line with an arbitrary curve that is concave with respect to the rotation direction to form the blade leading edge, the blade at the portion near the boss at the blade leading edge at high pressure loss Of the flow from the pressure surface 9 to the suction surface 8 due to the vertical vortex, the flow follows the blade surface, and the suction flow is blown to the outside while being guided by the vertical vortex. At this time, the disturbance of the flow on the blade negative pressure surface due to the separation of the suction flow near the blade front edge portion 1b can be eliminated, and the noise can be reduced.

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

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 symbols as in FIG. 34 indicate the same components. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. In the figure, in the coordinate system with the rotation axis as the origin O and the straight line connecting the point O and the arbitrary point 1bs' on the blade leading edge 1b 'as the X axis, the straight line O-1bs' is centered at the origin O. The tangent line at the intersection point 1bb ′ with the side surface of the boss portion when rotated by β in the rotational direction and the tangent line at the point 1bs ′ are knotted blade front edge portion 1b ′ with an arbitrary curve that is concave with respect to the rotational direction. It forms a blade shape that is tied together.

By forming in this way, at the time of high pressure loss, 1bs'- which is a part of the blade leading edge 1b 'in FIG.
The 1bs in FIG. 36, which is an X-X section of 1bb ′.
By the stable vertical vortex 10 generated by the wraparound of the flow from the pressure surface 9 of -1 bb to the suction surface 8, the flow follows the vane surface, and the suction flow 12 is blown to the outside while being guided by the vertical vortex 10. It Accordingly, as a problem in the conventional axial blower, as shown in FIG.
Suction flow 1 near the blade leading edge 1b at the time of high pressure loss
The turbulence of the flow on the blade negative pressure surface 8 due to the separation of 2 can be eliminated,
It is possible to reduce noise.

Here, the point 1 when extending the portion 1bs'-1bb 'from the boss portion 2 of the blade front edge portion 1b in the rotational direction
If the rotation angle β when the position of bs and the straight line O-1bs is rotated about the origin O and the intersection point 1bb with the side surface of the boss portion 2 is determined is too large or too small, the blades are disturbed on the contrary. And the noise gets worse. Therefore, the position of the point 1bs on the blade leading edge 1b and the rotation angle β
There exists an optimum range of. FIG. 37 shows the position of the point 1bs on the blade leading edge portion 1b when the rotation angle β is constant by the ratio of the radius Rs at the point 1bs to the blade outer peripheral radius Rt.
This is an experimentally obtained effect on noise characteristics. 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 becomes the minimum is the minimum specific noise Ksmin.
Is graphed as. Here, the specific noise Ks is defined by the following equation. Ks = SPL-10Log (Q ・ Ps2.5) SPL: Noise characteristic (SOUND PRESSURE LEVEL) [dB
(A)] Q: Air volume [m3 / min]

Ps: Static pressure [mmAq] As shown in the figure, when the radius Rs at the position of 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. Further, Rs / Rt = 0 (on the Y-axis) in the figure indicates the value of the conventional axial-flow blower. As a result, it can be seen that the maximum noise level is 2 [dB (A)] lower than the conventional value. FIG. 38 shows experimentally obtained influence of the rotation angle β in FIG. 35 on the noise characteristic when the ratio Rs / Rt indicating the position of the point 1bs is constant. At this time, the specific noise K
Since s changes depending on the operating point, the value at the operating point where the specific noise Ks is minimum is plotted 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 the straight line O-1bs connecting bs and the origin O is rotated 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. Also, the value around -10 ° in the figure is
The values of the conventional axial blower are shown, and it can be seen that the axial blower according to the present invention has a maximum noise of 2 [dB (A)] as compared with the conventional one. FIG. 39 is an experimental study of the influence of the ratio Rs / Rt of the radius Rs at the position of the point 1bs on the blade leading edge to the blade outer radius Rt and the rotation angle β on the noise characteristics.
The results of graphing the values at the operating point where the specific noise Ks is minimized are 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.

In this axial blower, a boss portion having blades attached thereto and rotating, a blade front edge portion facing in the rotation direction, a blade trailing edge portion facing in the direction opposite to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is formed by a portion, a rotation axis O and a blade outer peripheral radius of 40 to 75 on a blade leading edge portion are included. The straight line O-1bs 'connecting the point 1bs' having a radius of 10% is rotated about the origin O by 10 to 40 °
Between the straight line O-1bs' and the side surface of the boss portion which is the radius of the boss portion 1bb 'and 1b'.
Since the blade shape is formed by connecting the tangent line at s ′ with an arbitrary curve that is concave with respect to the rotation direction to form the blade leading edge portion, at the time of high pressure loss, near the boss portion of the blade leading edge portion. A longitudinal vortex generated by the wraparound of the flow from a certain 1bs'-1bb 'pressure surface 9 to the suction surface 8 causes the flow to follow the vane surface, and the suction flow is guided to this longitudinal vortex and is blown to the outside. As a result, the disturbance of the flow on the blade negative pressure surface due to the separation of the suction flow near the blade front edge portion 1b at the time of high pressure loss can be eliminated, and noise can be reduced.

Seventh Embodiment Another embodiment will be described below 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, for example, a three-blade shape, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade leading edge portion, 1d denotes a blade outer peripheral portion, and 1C denotes a blade trailing edge portion. 41 shows a front view of FIG. 40. FIG. 42 shows
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 symbols as in FIG. 41 indicate the same components. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. In the figure, the blade shape is formed so that the connecting portion between the blade leading edge portion and the boss portion is connected by an R curve having a radius of 15 to 35% of the blade outer peripheral portion radius Rt to form the blade leading edge portion. ing.

By forming in this way, at the time of high pressure loss, the blade leading edge portion 1b 'of FIG.
In Fig. 3, the stable longitudinal vortex 10 generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 causes the flow to follow the vane surface, and the suction flow 12 is guided to the longitudinal vortex 10 as shown in Fig. 44. Is blown to the outside. Therefore, as a problem in the conventional axial blower, FIG.
It is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade front edge portion 1b at the time of high pressure loss as shown in FIG.

Further, in the conventional axial blower, as a measure against the forced high rotation of the fan due to a strong wind such as a typhoon, as shown in FIG. 98, the blade front edge portion 1b near the boss portion and the boss portion 2 are provided. A part of the blade of the connecting part was thickened to avoid the stress concentration due to the strong wind at the base of the blade and prevent the damage. Therefore, as shown in FIG. 103, which is a developed view of the BB cross section of FIG. 98, the suction flow 12 collides with the blade leading edge portion 1b having a large plate thickness, and the suction flow 11 on the suction surface is disturbed. It was In the present invention, the blade leading edge portion 1
Since the connecting portion between b near the boss portion and 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 of the connecting portion between the blade leading edge portion 1b and the boss portion 2 is too small or too large, the noise is worsened and the strength becomes insufficient. Therefore, there is an optimum range of the radius RR of this R curve.

FIG. 45 shows the effect on noise characteristics experimentally obtained by the ratio (= RR / Rt) of the radius Rr of the R curve to the radius Rt of the outer circumference of the blade.
At this time, the specific noise Ks changes depending on the operating point.
The value at the operating point where the specific noise Ks is the minimum is 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)] low noise compared to the conventional case. is there. Further, in FIG. 46, the value of the maximum stress σ near the blade front edge boss portion is experimentally obtained by the ratio of the blade outer peripheral radius Rt to the size of the radius RR of the R curve (= RR / Rt). Is. Figure 46
Therefore, the radius RR of the R curve is 15% of the blade outer radius Rt.
If it is above, it turns out that it has sufficient strength. Therefore,
45 and 46, if the radius RR of the R curve is within 15 to 35% of the blade outer peripheral radius Rt, the noise is low and the strength is sufficient.

In this axial blower, a boss portion having blades attached thereto and rotated, a blade front edge portion facing in the rotation direction, a blade trailing edge portion facing in the opposite direction to the rotation direction, and a blade outer periphery facing the boss portion. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a blade whose periphery is formed by a portion, the connecting portion between the blade leading edge portion and the boss portion is defined by the blade outer peripheral radius of 15 Since the blade shape is formed so as to be the blade front edge portion by connecting with an R curve having a radius of ˜35% as a radius, at the time of high pressure loss, in the blade front edge portion 1b ′ near the boss portion, A longitudinal vortex generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 causes the flow to follow the vane surface, and the suction flow is blown to the outside while being guided by the longitudinal vortex. Due to the separation of the suction flow near section 1b The turbulence of the flow on the blade negative pressure surface 8 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 a typhoon, the blade front edge portion 1b is closer to the boss portion. Near the boss portion of the blade front edge portion 1b, without increasing the thickness of the blade at the connecting portion between the vicinity and the boss portion 2 to avoid stress concentration due to the strong wind at the root of the blade and preventing damage. Since the connecting portion between and and the boss portion has a large R curve, stress concentration can be avoided, and it becomes unnecessary to locally increase the plate thickness.

Embodiment 8 Another embodiment will be described below 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, and the operation will be described mainly for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade leading edge portion, 1d denotes a blade outer peripheral portion, and 1C denotes a blade trailing edge portion. 48 shows a front view of FIG. 47.

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 symbols as in FIG. 48 indicate the same items. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. In the figure, the blade outer peripheral radius Rt and the blade boss radius Rb of the base blade 10 'shown by the broken line in the figure
Point 1bs' on the blade leading edge 1bO 'having an arbitrary radius Rs between (1bs': blade leading edge boss extension start point),
Blade front edge 1b having a boss radius Rb which is the base of the blade
A straight line 1baO 'connecting the origin O with the point 1baO' on O '
-O is an angle δαb (δα
b: Point 1 when rotated by the blade leading edge boss advance extension angle)
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 extension extension angle δαb,
Assuming a point 1bc ′ at an arbitrary radius Rc between the radius Rb and the radius Rs when extended 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) so that the base blade 1 is continuous with the blade 1.
Based on the blade leading edge 1b of O ', the blade leading edge boss extension end point 1b of radius Rs passes from the blade leading edge boss extension start point 1bs' to the point 1bc'.
A blade shape is formed by advancing and extending the blade leading edge portion 1bO ′ between b ′ in the rotation direction.

In FIG. 50, when the blade surface is formed with the blade chord line center point PbO ′ at the boss radius Rb of the base blade 1O ′ shown by the broken line in FIG. 49 as the relative origin, 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 is shown. The solid line indicates the blade 1 of the present invention. In the figure, the warp line 5 of the blades of the base has an arc shape, a warp angle θ that is a central angle for forming the arc, and a radius RR that forms the arc. Thus, the blade of the axial blower according to the present invention is different from the blade 1O of the base in the straight line 1ba shown in FIG.
The point 1bb 'at the boss radius Rb when the O'-O is rotated about the origin O in the direction of rotation by δαb is extended to the point 1bb in the development view of FIG. 50 by the same arc in the direction of rotation. ..

By forming in this way, at the time of high pressure loss, it is an XX cross section taken along the radius Rc in FIG.
In Fig. 52, the stable longitudinal vortex 10 generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 causes the flow to follow the vane surface, and the suction flow 12 is guided by the longitudinal vortex 10 as shown in Fig. 52. It is blown to the outside. Therefore, as a problem in the conventional axial blower, FIG.
It is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade front edge portion 1b at the time of high pressure loss as shown in FIG. Further, in the conventional axial blower, as a measure against the forced high rotation of the fan due to a strong wind such as a typhoon, as shown in FIG. 98, the connecting portion between the boss portion 2 near the boss portion of the blade front edge portion 1b is connected. Part of the blade of the blade was thickened to avoid stress concentration due to strong wind at the root of the blade and prevent damage. Therefore, FIG. 10 which is a developed view of the BB cross section of FIG. 98.
As shown in FIG. 3, the suction flow 12 collided with the blade leading edge portion 1b having a large plate thickness, and the suction flow 11 on the suction surface was disturbed. In the present invention, as shown in FIG. 37, since the connecting portion between the blade 1 and the boss portion is formed in a rounded shape with a rounded shape, stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

However, when the blade boss advance extension angle δαb and the radius Rs at the blade leading edge boss extension start point 1bs' when the straight line 1ba'-O is rotated around the origin O are too large, the result is shown in FIG. As shown in the corresponding FIG. 53, the suction flow 12 collides with the blade leading edge portion 1bb, causing turbulence on the blade surface and deteriorating noise. Therefore, there is an optimum range of the angle δαb and the radius Rs. FIG. 54 is a graph in which the influence on the noise characteristics is experimentally obtained by the size of the blade leading edge boss extension extension angle δαb when the radius Rs at the blade leading edge boss extension starting point 1bs is 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 becomes the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, if the blade leading edge boss advance extension angle δαb is between 20 and 50 °, the minimum specific noise Ksmi is lower than that of the conventional axial flow fan that is the base blade.
The value of n is small, and the maximum noise is 2.5 [dB (A)].

FIG. 55 shows the advance extension angle δα of the blade leading edge boss portion.
When b = constant, the influence on the noise characteristics was experimentally determined by the size of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss extension extension start point 1bs ′ in FIG. Is what I asked for. At this time, the specific noise Ks
Changes depending on the operating point, so the value at the operating point where the specific noise Ks is the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss extension starting point 1bs ′ is 4 of the blade outer peripheral radius Rt.
If it is in the range of 0 to 70%, the minimum specific noise Ksmin is low, which is a maximum of 2.5 [dB (A)] low noise as compared with the conventional axial flow fan that is the blade of the base. FIG. 56 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs and the outer radius Rt of the blade at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss advance extension angle δαb on the noise characteristics. This is a graph of the values at the operating point where the specific noise Ks was minimized after examination. 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)].

FIG. 57 shows the blade start edge boss extension starting point 1b.
It is an experimental study of the influence of the ratio of the radius Rs of the blade to the blade outer peripheral radius Rt and the blade front edge boss advance extension angle δαb on the maximum stress σ on the blade. In the figure, the value in Rb / Rt indicates the maximum stress when the plate thickness is not locally thickened from the boss portion of the blade of the axial flow fan, which is the blade of the base. From the figure, if 0.4 ≦ Rs / Rt and 20 ° ≦ δαb, the strength of the blade is sufficient. Therefore, from FIGS. 56 and 57, 0.4 ≦ Rs / Rt ≦ 0.7 and 20
If ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotary axis of the axial blower having vanes whose circumferences are formed from opposing vane outer peripheral portions, the rotary axis is the origin O,
Point 1baO 'on the front edge of the blade at the base of the blade and the origin O
The straight line 1baO'-O connecting the points 1bbO'-O is rotated about the origin O by an angle δαb which is between 20 and 50 ° and the point 1bb ′ of the boss radius Rb and the blade outer radius 4
Point 1bs' on the blade leading edge with radius Rs of 0-70%
With respect to the shape of the blade, the boss radius Rb when the blade is rotated in the rotation direction by the angle δαb from the point 1ba ′ on the blade front edge which is the boss radius Rb of the blade. Of a straight line 1bC'-O and a straight line 1ba'-O connecting the origin O with a point 1bC 'having a radius Rc between the radius Rb and the radius Rs existing between the points 1bb' on the leading edge of the blade. The radial distribution of δα indicating the angle formed is 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 from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. Is.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade trailing edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having blades whose circumferences are formed from opposing blade outer peripheral portions, the rotation axis is the origin O,
Point 1baO 'on the front edge of the blade at the base of the blade and the origin O
The straight line 1baO'-O connecting the points 1bbO'-O is rotated about the origin O by an angle δαb which is between 20 and 50 ° and the point 1bb ′ of the boss radius Rb and the blade outer radius 4
Point 1bs' on the blade leading edge with radius Rs of 0-70%
With reference to the front edge of the blade, the shape between the points is a point 1baO ′ on the front edge of the blade that is the boss radius Rb of the blade.
From the point 1bC ′ of the radius Rc between the radius Rb and the radius Rs existing between the points 1bb ′ on the blade leading edge portion of the boss radius Rb when rotated in the rotation direction by the angle δαb.
And a straight line 1bC'-O connecting the origin O and a straight line 1baO '
The radial distribution of δα indicating the angle formed with −O is δα = (δαb / (Rb-RS) 2) × (R-RS) 2
(Rb ≦ R ≦ Rs), and the blade shape is formed by extending the blade front edge portion closer to the boss from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. Therefore, at the time of high pressure loss, the flow along the blade surface and the suction flow due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 at the boss portion of the blade front edge portion. It is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss, while being guided by this vertical vortex and to reduce noise. In addition, as a countermeasure when the fan is forced to rotate at high speed due to a strong wind such as a typhoon, part of the blade thickness near the boss near the blade front edge and the boss is thickened to 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.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having a vane having a vane whose outer circumferences are opposed to each other, a point 1ba ′ on the vane front edge portion of the root of the vane Straight line 1ba'-O connecting origin O
Is rotated about the origin O by an angle δαb which is between 20 and 50 ° in the rotation direction, and the point 1b of the boss radius Rb.
The shape between b ′ and a point 1bs ′ on the blade leading edge having a radius Rs of 40 to 70% of the blade outer peripheral radius is a boss radius Rb of the blade with the blade leading edge as a reference. Point 1 on the blade leading edge of the boss radius Rb when rotated in the rotation direction by the angle δαb from point 1ba ′ on the blade leading edge.
A straight line 1bC 'that connects the origin O with a point 1bC' having a radius Rc between the radius Rb and the radius Rs existing between bb 'and bb'.
The radial distribution of δα indicating the angle between O and the straight line 1ba′-O is δα = (δαb / (Rb-RS) 2) × (R-RS) 2
(Rb ≦ R ≦ Rs), and the blade shape is formed by extending the blade front edge portion closer to the boss from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. Therefore, at the time of high pressure loss, the flow along the blade surface and the suction flow due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 at the boss portion of the blade front edge portion. It is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss, while being guided by this vertical vortex and to reduce noise. In addition, as a countermeasure when the fan is forced to rotate at high speed due to a strong wind such as a typhoon, part of the blade thickness near the boss near the blade front edge and the boss is thickened to 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.

Ninth Embodiment Another embodiment will be described below with reference to the drawings. FIG. 58 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a three-blade shape, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 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 indicates the rotation axis of the blade 1 and 4 indicates the rotation direction

FIG. 59 shows a front view of FIG. L in this figure is the chord length, and indicates the circumferential distance (pitch) T between the blades. Further, Ls is a blade outer peripheral radius R
The chord length passing through the point 1bs on the blade leading edge portion 1b having a radius Rs of 40 to 60% of t is shown. FIG. 60 shows the rotary shaft 3
It is a projection view which projected wing 1 on the plane which intersects perpendicularly. In the figure, the same reference numerals as those in FIG. 59 denote the same elements.
1'is a blade in the projected view, 1b 'is a leading edge of the blade in the projected view, 1c' is a trailing edge of the blade in the projected view, 1d '
Is the outer peripheral portion of the blade in the projected 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 10 'shown by the broken line in the figure.
A point 1bs' on O '(1bs': start point of the blade leading edge boss extension), a point 1baO' on the blade leading edge 1bO 'having a boss radius Rb which is the root of the blade, and a straight line 1b connecting the origin O.
aO'-O is rotated about the origin O by an angle δαb
(Δαb: blade leading edge boss advance extension angle) When the point is 1bb ′ (1bb ′: blade leading edge boss extension end point) when rotated, from the radius Rs at the blade leading edge boss extension start point This is a shape in which the chord length of the blade up to the radius Rb at the blade leading edge boss extension end point 1bb ′ is extended in the rotational direction. Also, an arbitrary radius R between the radius Rs and the boss radius Rb
The point on the blade leading edge 1b ′ after the above 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 midpoint of O′-1cb ′, as the relative origin, when the blade surface is formed, the blade 10O ′ of the base is cut by the cylindrical surface of the boss radius Rb, The development view obtained by developing the cross section in a two-dimensional plane is shown. The solid line indicates the blade 1 of the present invention. In the figure, the warp line 5 of the blades of the base is formed into an arc shape, and the warp angle θ which is the central angle for forming the arc and the radius forming the arc are RRO.
The blade 1 is the same as the blade 1O of the base in the figure.
While the warp angle θ and the stagger angle ξ are the same, the boss radius R
The chord at b is extended in the rotational direction to the blade leading edge boss extension end point 1bb ′ shown in FIG. 60, and the chord length LbO and the point 1bb at the boss radius Rb of the blade 1O in this figure.
~ Chord length Lb to the blade trailing edge 1Cb, this difference is ΔLb
(= Lb-LbO), and the blade boss extension start point 1bs
Is the chord length LS at the radius Rs at R, the radial distribution of the chord length L from the boss radius Rb to the radius Rs is L = ΔLb / (Rs-Rb) 2 × (R-Rs) 2 + LS
(Rb ≦ R ≦ Rs) to form a blade shape.

With this structure, the chord length becomes longer than that of the base blade 1O as shown in FIG. 61, and the pressure rise on the blade surface can be increased.
62, which is an X-X cross section of FIG.
By 0, the flow is along the vane surface, and the suction flow is 1
The air 2 is guided to the vertical vortex 10 and is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise.

Further, in the conventional axial-flow blower, as a measure against the forced high rotation of the fan due to strong wind such as typhoon, as shown in FIG. 97, the blade front edge portion 1b near the boss portion and the boss portion 2 are provided. A part of the blade thickness of the connection part was thickened to avoid the stress concentration due to the strong wind at the root of the blade and prevent the damage. Therefore, as shown in FIG. 102 which is a developed view of the BB cross section of FIG. 97, the suction flow 12 collides with the blade leading edge portion 1b having a thick plate thickness, and the suction flow 11 on the suction surface is disturbed. It was In the present invention, as shown in FIG. 60, the connecting portion between the blade 1 and the boss portion is formed into a blade shape with a rounded shape, so that stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

However, when the straight line 1baO'-O is rotated about the origin O, the blade boss advance extension angle δα
b That is, when the chord length Lb at the boss radius Rb is too large, in FIG. 64 corresponding to FIG. 61, in the vicinity of the blade trailing edge portion 1Cb, the flow 11 and the vertical vortex 10 on the blade suction surface 8 are the blade suction surface. No. 8 is caused, or the entire circumference of the axial blower shown in FIG. 65 is cut by a cylindrical surface having a boss radius Rb, and its cross section is expanded into a two-dimensional plane. Flow 11 on the suction surface separated from suction surface 8
And the vertical vortex 10 disturbs the flow 13 of the pressure surface 9N of the blade 1N that swirls next, causing noise deterioration, and if the radius Rs at the blade leading edge boss 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 experimentally the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks [dB (A)] of the conventional conventional axial flow fan and the axial flow fan according to the embodiment of the ninth 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 the embodiment of the ninth invention. As can be seen from this characteristic diagram, compared with the conventional case, the operating region extends to the low air volume side and the static pressure is increased as a whole. On the other hand, the specific noise Ks can be reduced by 3 [dB (A)] at the maximum, which is low noise.

FIG. 67 shows the starting point 1b of the blade leading edge boss extension.
The effect on the noise characteristics was experimentally obtained by the size of the blade leading edge boss 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 becomes the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, the blade leading edge boss advance extension angle δαb
Is between 20 and 50 °, the minimum specific noise Ksmin is small and the maximum noise is 3.0 [dB (A)] as compared with the conventional axial flow fan that is the base blade.

FIG. 68 shows the forward extension angle δα of the blade leading edge boss.
When b = constant, the influence on the noise characteristics was experimentally determined by the size of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss extension starting point 1bs ′ in FIG. 60 and the blade outer peripheral radius Rt. Is what I asked for. At this time, the specific noise Ks
Changes depending on the operating point, so the value at the operating point where the specific noise Ks is the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss extension starting point 1bs ′ is 4 of the blade outer peripheral radius Rt.
If it is in the range of 0 to 60%, the minimum specific noise Ksmin is low, and the maximum noise is 3.0 [dB (A)] lower than that of the conventional axial flow fan that is the blade of the base. FIG. 69 shows experimentally the influence of the ratio (= Rs / Rt) of the radius Rs and the blade outer radius Rt at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss advance extension angle δαb on the noise characteristics. This is a graph of the values at the operating point where the specific noise Ks was minimized after examination.

From the figure, 0.4 ≦ Rs / Rt ≦ 0.6 and 20 °
If ≦ δαb ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and the noise is low. FIG. 70 is an experimental study on the influence of the ratio of the radius Rs and the outer radius Rt of the blade at the blade leading edge boss extension start point 1bs and the blade leading edge boss advance extension angle δαb on the maximum stress σ to the blade. It is a thing. R in the figure
The value indicated by b / Rt indicates the maximum stress when the plate thickness is not locally thickened from the blade front edge boss portion of the axial flow fan, which is the blade of the base. From the figure, 0.4 ≦ Rs
If / Rt and 20 ° ≦ δαb, the strength of the blade 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.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having blades whose circumferences are formed from opposing blade outer peripheral portions, the rotation axis is the origin O,
A straight line 1baO'-connecting the origin O with the point 1baO 'on the blade leading edge at the boss radius Rb of the blade 1O' of the base-
When O is rotated about the origin O in the rotation direction by an angle δαb that is between 20 and 50 °, and the point is the blade leading edge boss extension end point 1bb ′, the blade has a cylindrical surface with an arbitrary radius R. In a development view obtained by cutting the cross section with the blade and expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is set to the point 1bb while the blade 1O has the same warp angle θ and stagger angle ξ.
To the boss radius Rb of the blade 10 at this time
Chord length LbO and point 1bb to blade trailing edge portion 1C
The chord length Lb up to b, the difference being ΔLb, and the point 1 on the blade leading edge portion at a radius Rs of 40 to 60% of the blade outer peripheral radius.
Letting 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 = ΔLb / (Rs−Rb) 2 × (R− Rs) 2 + LS
(Rb ≦ R ≦ Rs) to form a blade shape.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having blades whose circumferences are formed from opposing blade outer peripheral portions, the rotation axis is the origin O,
A straight line 1baO'-connecting the origin O with the point 1baO 'on the blade leading edge at the boss radius Rb of the blade 1O' of the base-
When O is rotated about the origin O in the rotation direction by an angle δαb that is between 20 and 50 °, and the point is the blade leading edge boss extension end point 1bb ′, the blade has a cylindrical surface with an arbitrary radius R. In a development view obtained by cutting the cross section with the blade and expanding the cross section into a two-dimensional plane, the chord at the boss radius Rb is set to the point 1bb while the blade 1O has the same warp angle θ and stagger angle ξ.
To the boss radius Rb of the blade 10 at this time
Chord length LbO and point 1bb to blade trailing edge portion 1C
The chord length Lb up to b, the difference being ΔLb, and the point 1 on the blade leading edge portion at a radius Rs of 40 to 60% of the blade outer peripheral radius.
Letting 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 = ΔLb / (Rs−Rb) 2 × (R− Rs) 2 + LS
(Rb ≦ R ≦ Rs), the blade shape is formed, so that the chord length is longer than that of the base blade 10 and the pressure rise on the blade surface is increased. At the edge of the edge portion near the boss portion, the flow is along the blade surface due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the negative pressure surface 8, and the suction flow is guided to this vertical vortex and is blown to the outside. As a result, the disturbance of the flow on the suction surface of the blade due to the separation of the suction flow near the blade front edge at the time of high pressure loss can be eliminated, and noise can be reduced, and the fan is forced to rise by strong wind such as typhoon. As a measure when rotating,
A part of the blade is thickened near the boss near the front edge of the blade and at the connection between the boss and the blade 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 portion of each portion is formed into a blade shape with a radius of R, stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

In the axial blower according to the present invention, the boss portion having the blade attached thereto and rotated, the blade front edge portion facing in the rotation direction, the blade rear edge portion facing in the direction opposite to the rotation direction, and the boss portion are provided. In a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis of the axial blower having vanes whose circumferences are formed of opposing vane outer peripheral portions, the vane leading edge at the boss radius Rb of the vane 1O ′ of the base Point 1baO 'on the part and a straight line 1baO'-O connecting the origin O are rotated about the origin O by an angle δαb which is between 20 and 50 °. When the extension end point is 1 bb ', the blade is cut along a cylindrical surface with an arbitrary radius R and its cross section is divided into 2
In a development view obtained by developing on a three-dimensional plane, the chord at the boss radius Rb is extended to the point 1bb with the same deflection angle θ and stagger angle ξ as the blade 10 and the blade at this time. Chord length LbO at boss radius Rb of 10
And the chord length Lb from the point 1bb to the blade trailing edge portion 1Cb,
Let this difference be ΔLb, and let the chord length LS at the point 1bs on the blade leading edge portion at a radius Rs of 40 to 60% of the blade outer peripheral radius be the boss radius Rb on the blade leading edge portion. Point 1b
The radial distribution of the chord length L up to s is L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
(Rb ≦ R ≦ Rs), the blade shape is formed, so that the chord length is longer than that of the base blade 10 and the pressure rise on the blade surface is increased. At the edge of the edge portion near the boss portion, the flow is along the blade surface due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the negative pressure surface 8, and the suction flow is guided to this vertical vortex and is blown to the outside. As a result, the disturbance of the flow on the suction surface of the blade due to the separation of the suction flow near the blade front edge at the time of high pressure loss can be eliminated, and noise can be reduced, and the fan is forced to rise by strong wind such as typhoon. As a measure when rotating,
A part of the blade is thickened near the boss near the front edge of the blade and at the connection between the boss and the blade 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 portion of each portion is formed into a blade shape with a radius of R, stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

Tenth Embodiment Another embodiment will be described below with reference to the drawings. FIG. 71 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a three-blade shape, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade leading edge portion, 1d denotes a blade outer peripheral portion, and 1C denotes a blade trailing edge portion. FIG. 72 is a front view of FIG. 71. In the figure, L is the chord length, and the value of the chord ratio T / L defined by the ratio with T, which is the circumferential distance (pitch) between the blades, is T / L = 1. It is set to 1 to 2.0. FIG. 73 shows
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 indicate the same elements. Reference numeral 1'denotes a blade in the projection drawing, 1b 'denotes a blade leading edge portion in the projection drawing, 1c' denotes a blade trailing edge portion in the projection drawing, and 1d 'denotes a blade outer peripheral portion in the projection drawing. Also,
In the figure, the broken line is a blade 10O 'which becomes a base when forming the blade 1'of the axial blower according to the present invention, 1bO' is a blade leading edge portion of the base blade, and 1dO 'is a blade blade of the base. The outer peripheral portion, 1CO ', indicates the blade trailing edge portion of the blade that is the base.

Further, the blade 1O 'of the base is cut from the rotary shaft 3 with a cylindrical surface of an arbitrary radius R, and its cross section is developed 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 chord line center point in the projection drawing in which the blade 1O 'is projected on the plane orthogonal to the rotation axis 3. PRO 'in this projection
In order to clarify the position of, the blade 1O ′ is cut at the cylindrical surface of the boss radius Rb and the cross section is developed into a two-dimensional plane, which is taken as the boss chord chord line center point PbO ′, A straight line Pb connecting the position O on the projection of the rotation axis 3
A coordinate system with O′-O as the X axis and O as the origin is formed on the projection view. Further, PtO ′ is the center point of the chord line in 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 rotational direction), the angle between the straight line PtO′−O connecting the chord line center point PtO ′ at the blade outer periphery and the origin O and the X axis is δθt, and δθ = δθt × (R -R
b) / (Rt-Rb), and δθt = 25-40 °.

In the axial blower according to the present invention, the outer peripheral radius R of the blade 10O 'of the base shown by the broken line in the figure is R.
Point 1bs'(1bs': blade leading edge boss extension start point) on blade leading edge 1bO 'having an arbitrary radius Rs between t and blade boss radius Rb, boss radius Rb which is the root of the blade The 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 an angle δαb (δαb: blade leading edge boss advance extension angle). When the point is 1 bb '(1 bb': end point of the blade leading edge boss extension) when the straight line 1 baO'-O is 0 °
-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 advance extension angles δαb and extended in the blade outer peripheral direction.
Then, the radial distribution of the arbitrary rotation angle δα at this time is δα = (δαb / (Rb-RS) 2) × (R-RS) 2
(Rb ≦ R ≦ Rs) so that the base blade 1 is continuous with the blade 1.
Based on the blade leading edge 1b of O ', the blade leading edge boss extension end point 1b of radius Rs passes from the blade leading edge boss extension start point 1bs' to the point 1bc'.
A blade shape is formed by advancing and extending the blade leading edge portion 1bO ′ between b ′ in the rotation direction.

In FIG. 74, when the blade surface is formed with the blade chord line center point PbO ′ at the boss radius Rb of the base blade 1O ′ shown by the broken line in FIG. 73 as the relative origin, 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 is shown. The solid line indicates the blade 1 of the present invention. In the figure, the warp line 5 of the blades of the base has an arc shape, a warp angle θ that is a central angle for forming the arc, and a radius RR that forms the arc. At this time, the radial distribution of the deflection angle θ is θ = (θt−θb) × (R−Rb) / (Rt−Rb) +
Let θb (θt: warp angle at blade outer periphery, θb: warp angle at blade boss portion), θt = 25 to 35 °, θb = 30 to 55 °, θt
<Θb. The blade mounting position is defined by the angle ξ between the chord line 1baO-1CO and the straight line 6 parallel to the rotating shaft 3 and passing through the blade front edge 1baO of the base blade 1O, and the radius ξ It is determined by giving the distribution of directions. That is, the radial distribution of ξ is ξ = (ξt−ξb) × (R−Rb) / (Rt−Rb) +
ξb (ξt: stagger angle at blade outer periphery, ξb: stagger angle at blade boss), ξt = 55 to 70 °, ξb = 40 to 65 °, ξt
> Ξb. In contrast to the blade 1O of such a base, the blade of the axial blower according to the present invention has a boss radius Rb when the straight line 1baO′-O shown in FIG. 73 is rotated δαb in the rotation direction about the origin O. Figure 74 at point 1bb '
The point up to the point 1bb in the development view of is extended in the rotational direction with the same arc.

By forming in this manner, at the time of high pressure loss, the cross section taken along the line XX in the radius Rc of FIG. 73 is shown.
At, in the vertical vortex 10 generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8, the flow is along the blade surface,
Moreover, the suction flow 12 is guided to the vertical vortex 10 and is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise. Further, in the conventional axial blower, as a measure against the forced high rotation of the fan due to a strong wind such as a typhoon, as shown in FIG. 98, the connecting portion between the boss portion 2 near the boss portion of the blade front edge portion 1b is connected. Part of the blade of the blade was thickened to avoid stress concentration due to strong wind at the root of the blade and prevent damage. Therefore, FIG.
As shown in FIG. 103 which is a developed view of the BB cross section of No. 3, the suction flow 12 collided with the blade leading edge portion 1b having a thick plate thickness, and the suction flow 11 on the suction surface was disturbed. In the present invention, as shown in FIG. 73, since the connecting portion between the blade 1 and the boss portion is formed in a blade shape with a rounded shape, stress concentration can be avoided and it is not necessary to locally increase the plate thickness.

However, the straight line 1baO'-O is the origin O.
Blade boss advance extension angle δαb when rotating to the center
And the radius Rs at the blade leading edge boss extension starting point 1bs'
Is too large, as shown in FIG. 77 corresponding to FIG. 74, the suction flow 12 collides with the blade leading edge portion 1bb, causing turbulence on the blade surface and deteriorating noise.
And the strength is insufficient. Therefore, there is an optimum range of the angle δαb and the radius Rs. FIG. 78 is an experimental result of the influence on the noise characteristic depending on the size of the blade leading edge boss advance extension angle δαb when the radius Rs at the blade leading edge boss extension start point 1bs is 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 becomes the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, when the blade leading edge boss advance extension angle δαb is between 20 and 50 °, the minimum specific noise Ksm is lower than that of the conventional axial flow fan that is the base blade.
The value of in is small, and the maximum noise is 2.5 [dB (A)].

FIG. 79 shows the advance extension angle δα of the blade leading edge boss portion.
When b = constant, the influence on the noise characteristics was experimentally determined by the size of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss extension starting point 1bs ′ in FIG. 73 and the blade outer radius Rt. Is what I asked for. At this time, the specific noise Ks
Changes depending on the operating point, so the value at the operating point where the specific noise Ks is the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss extension starting point 1bs ′ is 4 of the blade outer peripheral radius Rt.
If it is in the range of 0 to 70%, the minimum specific noise Ksmin is low, which is a maximum of 2.5 [dB (A)] low noise as compared with the conventional axial flow fan that is the blade of the base. FIG. 80 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs and the blade outer radius Rt at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss advance extension angle δαb on the noise characteristics. This is a graph of the values at the operating point where the specific noise Ks was minimized after examination. 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)]. FIG. 81 shows the ratio of the radius Rs to the outer radius Rt of the blade at the blade leading edge boss extension start point 1bs and the blade leading edge boss advance extension angle δα.
This is an experimental study of the effect of b on the maximum stress σ on the blade. In the figure, the value in Rb / Rt indicates the maximum stress when the plate thickness is not locally thickened from the boss portion of the blade of the axial flow fan, which is the blade of the base. From the figure, if 0.4 ≦ Rs / Rt and 20 ° ≦ δαb,
The strength of the blade is sufficient. Therefore, from FIGS. 80 and 81, 0.
If 4 ≦ Rs / Rt ≦ 0.7 and 20 ° ≦ δαb ≦ 50 °, a blade with low noise and sufficient strength can be obtained.

In this axial blower, the boss portion with the blades attached and rotating, the blade front edge portion facing in the rotation direction, the blade trailing edge portion facing in the direction opposite to the rotation direction, and the blade outer periphery facing the boss portion. In a development view obtained by cutting a blade of an axial-flow blower having a blade whose periphery is formed by a section 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 central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (RR
b) / (Rt−Rb) + θb (θt: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt <
Let θb be the angle between the chord line of the blade and the straight line that is parallel to the rotation axis and that passes through the leading edge of the blade in the above developed view and is ξ (ξ: stagger angle). Ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle ξ, ξ at the outer periphery of the blade
b: stagger angle at boss radius Rb), ξt
= 55 ° to 70 °, ξb = 40 ° to 65 °, ξt> ξb, and L in this figure is the chord length, which is the circumferential distance (pitch) between the blades shown in FIG. T
And the value of the chordal ratio T / L defined by the ratio of T and L is 1.1 to 2.0 at each radial point, and the axial blower is projected on a plane orthogonal to the rotation axis. In the figure, Pb 'is the center point of the chord line in the cross section when cut by a cylindrical surface having the boss radius Rb of the blade, the rotation axis is the origin O, and a straight line connecting the points O and Pb' is In the coordinate system with the X-axis, the angle between the straight line PR'-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: angle formed by the straight line Pt′−O and the X axis), and δθt
Is 25 to 40 °, a blade shape is first formed, and a straight line 1baO′-O connecting a point 1baO ′ on the blade leading edge portion of the blade root and the origin O at this time is rotated about 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 circumference radius of 40˜.
From the point 1baO ′ on the blade leading edge which is the boss radius Rb of the blade with respect to the blade leading edge, the shape between points 1bs ′ on the blade leading edge having a radius Rs of 70% is used. A point 1bC 'of a radius Rc between a radius Rb and a radius Rs existing between points 1bb' on the blade leading edge portion of the boss radius Rb when rotated in the rotation direction by the angle δαb and an origin O. The radial distribution of δα indicating the angle formed by the straight line 1bC′−O and the straight line 1baO′−O that connect is δα = (δαb / (Rb−RS) 2) × (R−RS) 2
(Rb ≦ R ≦ Rs), and the blade shape is formed by extending the blade front edge portion closer to the boss from the point 1bs ′ on the blade front edge portion in the rotation direction so as to be continuous with the blade. Therefore, at the time of high pressure loss, the flow along the blade surface and the suction flow due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8 at the boss portion of the blade front edge portion. It is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss, while being guided by this vertical vortex and to reduce noise. In addition, as a countermeasure when the fan is forced to rotate at high speed due to a strong wind such as a typhoon, part of the blade thickness near the boss near the blade front edge and the boss is thickened to 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 Another embodiment will be described below with reference to the drawings. FIG. 82 is a perspective view showing an embodiment of the axial blower according to the present invention, which has, for example, a three-blade shape, and the operation will be mainly described for one blade 1, but the same applies to other blades. Is. In the figure, 1 is a blade of an axial blower having a three-dimensional shape, 2 is a boss portion to which the blade is attached,
Reference numeral 3 denotes a rotation axis of the blade 1, 4 denotes an arrow indicating a rotation direction, 1b denotes a blade leading edge portion, 1d denotes a blade outer peripheral portion, and 1C denotes a blade trailing edge portion. 83 is a plan view of FIG. 82. In the figure, L is the chord length, and the value of the chordal chord ratio T / L defined by the ratio with T, which is the circumferential distance (pitch) between the blades, at each radius point,
T / L = 1.1 to 2.0.

FIG. 84 is a projection view in which the blade 1 and the blade 1O ′ which is the base of the blade 1 ′ are projected on the plane orthogonal to the rotation axis 3. In the figure, the same symbols as those in FIG. 83 denote the same elements. 1'is the blade in the projection, 1b '
Is a blade front edge portion in the projection view, 1c ′ is a blade trailing edge portion in the projection view, and 1d ′ is a blade outer peripheral portion in the projection view. In addition, the broken line in the figure is a blade 1O 'which is a base for forming the blade 1'of the axial blower according to the present invention, and 1b.
O'denotes the blade leading edge portion of the base blade, 1dO 'denotes the blade outer peripheral portion of the base blade, and 1CO' denotes the blade trailing edge portion of the base blade. Further, the blade 1O 'of the base is cut from the rotary shaft 3 with a cylindrical surface having an arbitrary radius R, and its cross section is developed into a two-dimensional plane.
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 drawing in which the blade 1O 'is projected on the plane orthogonal to the rotation axis 3. In order to clarify the position of PRO 'in this projection view, the boss radius Rb
The blade 1O ′ is cut along the cylindrical surface of the above, and its cross section is expanded to a two-dimensional plane to be the boss chord line center point PbO ′ in the developed view, and a straight line connecting 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. Further, PtO ′ is the center point of the chord line in 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 δθ (δθ: forward direction angle in the rotational direction), and the straight line Pt connecting the chord line center point PtO ′ at the blade outer periphery and the origin O.
Let δθt be the angle between O′-O and the X axis, and give by δθ = δθt × (R−Rb) / (Rt−Rb)
δθt = 25-40 °. The axial blower according to the present invention has a point 1bs on the blade leading edge 1bO 'having an arbitrary radius Rs between the blade outer radius Rt and the blade boss radius Rb of the blade 1O' of the base shown by the broken line in the figure. '(1bs': blade leading edge boss extension start point), a point 1baO 'on the blade leading edge 1bO' having a boss radius Rb which is the root of the blade, and a straight line 1baO'-O connecting the origin O are the origins. Angle δα in the direction of rotation around O
Point 1bb '(1bb': blade leading edge boss extension end point) when rotated by b (δαb: blade leading edge boss extension extension angle)
In this case, the blade chord length from the radius Rs at the blade leading edge boss extension start point to the radius Rb at the blade leading edge boss extension end point 1bb ′ is extended in the rotational direction. Details are given in the following figure.

In FIG. 85, when the blade surface is formed with the blade chord line center point PbO ′ at the boss radius Rb of the blade 10O ′ of the base shown by the broken line in FIG. 84 as the relative origin, 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 is shown. The solid line indicates the blade 1 of the present invention. In the figure, the warp line 5 of the blades of the base is formed into an arc shape, and the warp angle θ which is the central angle for forming the arc and the radius forming the arc are RRO. At this time, the radial distribution of the deflection angle θ is θ = (θt−θb) × (R−Rb) / (Rt−Rb) +
Let θb (θt: warp angle at blade outer periphery, θb: warp angle at blade boss portion), θt = 25 to 35 °, θb = 30 to 55 °, θt
<Θb. The blade mounting position is defined by the angle ξ between the chord line 1baO-1CO and the straight line 6 parallel to the rotating shaft 3 and passing through the blade front edge 1baO of the base blade 1O, and the radius ξ It is determined by giving the distribution of directions. That is, the radial distribution of ξ is ξ = (ξt−ξb) × (R−Rb) / (Rt−Rb) +
ξb (ξt: stagger angle at blade outer periphery, ξb: stagger angle at blade boss), ξt = 55 to 70 °, ξb = 40 to 65 °, ξt
> Ξb. In contrast to the blade 1O of such a base, the blade 1 of the axial-flow fan according to the present invention has the same boss radius Rb and the same deflection angle θ and stagger angle ξ as those of the blade 1O.
The chord in Fig. 84 is the end point 1 of the blade leading edge boss extension shown in Fig.
It extends to the rotation direction up to bb ',
Chord length LbO at boss radius Rb of O and point 1bb
The chord length Lb to the blade trailing edge 1Cb, this difference is ΔLb
(= Lb-LbO), and the blade boss extension start point 1bs
Is the chord length LS at the radius Rs at R, the radial distribution of the chord length L from the boss radius Rb to the radius Rs is L = ΔLb / (Rs-Rb) 2 × (R-Rs) 2 + LS
(Rb ≦ R ≦ Rs) to form a blade shape.

By forming in this way, as shown in FIG. 85, the chord length becomes longer than that of the base blade 1O, the pressure rise on the blade surface can be increased, and at the time of high pressure loss, FIG.
86 which is a YY cross section of FIG. 86, the stable vertical vortex 1 generated by the wraparound of the flow from the pressure surface 9 to the suction surface 8
By 0, the flow is along the vane surface, and the suction flow is 1
2 is guided to the vertical vortex 10 and is blown to the outside as shown in FIG. Thus, as a problem in the conventional axial blower, it is possible to eliminate the turbulence of the flow 11 on the blade suction surface 8 due to the separation of the suction flow 12 near the blade leading edge portion 1b at the time of high pressure loss as shown in FIG. It is possible to reduce noise. Further, in the conventional axial blower, as a measure against the forced high rotation of the fan due to a strong wind such as a typhoon, as shown in FIG. 98, the connecting portion between the boss portion 2 near the boss portion of the blade front edge portion 1b is connected. Part of the blade of the blade was thickened to avoid stress concentration due to strong wind at the root of the blade and prevent damage. Therefore, as shown in FIG. 103, which is a developed view of the BB cross section of FIG. 98, the suction flow 12 collides with the blade leading edge portion 1b having a large plate thickness, and the suction flow 11 on the suction surface is disturbed. It was In the present invention, FIG.
As shown in Fig. 4, since the connecting portion between the blade 1 and the boss portion is formed into a blade shape with a rounded shape, stress concentration can be avoided,
It is not necessary to locally increase the plate thickness.

However, when the blade boss advance extension angle δαb when the straight line 1ba′-O is rotated about the origin O, that is, when the chord length Lb at the boss radius Rb is too large, FIG. 88 corresponding to FIG. At the blade trailing edge 1Cb
In the vicinity, the flow 11 on the blade suction surface 8 and the vertical vortex 10 cause separation from the blade suction surface 8, or the entire circumference of the axial blower shown in FIG. As shown in the full-circle development diagram obtained by developing on a two-dimensional plane,
Flow 11 on the suction surface separated from suction surface 8 of blade 1 and flow 1 on pressure surface 9N of blade 1N where vertical vortex 10 swirls next
3 is disturbed, noise is deteriorated, and if the radius Rs at the blade leading edge boss extension start point 1bs' is too small, the effect is lost and the strength becomes insufficient. Therefore, there is an optimum range of the angle δαb and the radius Rs.

FIG. 90 shows the relationship between the flow coefficient φ and the pressure coefficient ψ and the specific noise Ks of the conventional axial fan as the base and the axial fan according to the embodiment of the eleventh invention.
It is the characteristic view which experimentally calculated | required [dB (A)]. The black circles and black squares in the figure indicate the characteristics and minimum specific noise of the conventional axial blower.
The symbols x and □ represent the characteristics and the minimum specific noise of the axial flow fan in the embodiment of the eleventh invention. As can be seen from this characteristic diagram, compared with the conventional case, the operating region extends to the low air volume side and the static pressure is increased as a whole. On the other hand, the specific noise Ks can be reduced by 3 [dB (A)] at the maximum, which is low noise. FIG. 91 is an experimental result of the influence on the noise characteristic depending on the size of the blade leading edge boss advance extension angle δαb when the radius Rs at the blade leading edge boss extension start point 1bs is 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 the minimum is the minimum specific noise Ksm.
Graphed as in. As shown in the figure, when the blade leading edge boss advance extension angle δαb is between 20 and 50 °, the value of the minimum specific noise Ksmin is small compared to the conventional axial flow fan that is the base blade, and the maximum value is 3 or less. 0.0 [dB (A)]
It has low noise.

FIG. 92 shows the blade leading edge boss advance extension angle δα.
When b = constant, the influence on the noise characteristic was experimentally determined by the size of the ratio (= Rs / Rt) of the radius Rs at the blade leading edge boss extension start point 1bs ′ in FIG. 47 and the blade outer peripheral radius Rt. Is what I asked for. At this time, the specific noise Ks
Changes depending on the operating point, so the value at the operating point where the specific noise Ks is the minimum is plotted as the minimum specific noise Ksmin. As shown in the figure, the radius Rs at the blade leading edge boss extension starting point 1bs ′ is 4 of the blade outer peripheral radius Rt.
If it is in the range of 0 to 60%, the minimum specific noise Ksmin is low, and the maximum noise is 3.0 [dB (A)] lower than that of the conventional axial flow fan that is the blade of the base. FIG. 93 shows experimentally the effect of the ratio (= Rs / Rt) of the radius Rs and the blade outer radius Rt at the blade leading edge boss extension start point 1bs and the effect of the blade leading edge boss advance extension angle δαb on the noise characteristics. This is a graph in which the values at the operating point where the specific noise Ks is minimized are examined.

From the figure, 0.4 ≦ Rs / Rt ≦ 0.6 and 20 °
If ≦ δαb ≦ 50 °, the minimum specific noise Ksmin is sufficiently small and the noise is low. In FIG. 94, the effect of the ratio of the radius Rs at the blade leading edge boss extension starting point 1bs to the blade outer peripheral radius Rt and the influence of the blade leading edge boss forward extension angle δαb on the maximum stress σ on the blade was experimentally examined. It is a thing. R in the figure
The value indicated by b / Rt indicates the maximum stress when the plate thickness is not locally thickened from the blade front edge boss portion of the axial flow fan, which is the blade of the base. From the figure, 0.4 ≦ Rs
If / Rt and 20 ° ≦ δαb, the strength of the blade 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.

In this axial blower, the boss portion with the blades attached and rotating, the blade front edge portion facing in the rotation direction, the blade trailing edge portion facing in the direction opposite to the rotation direction, and the blade outer periphery facing the boss portion. In a development view obtained by cutting a blade of an axial-flow blower having a blade whose periphery is formed by a section 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 central angle for forming the arc is θ (θ: warp angle), the radial distribution of θ is θ = (θt−θb) × (RR
b) / (Rt−Rb) + θb (θt: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θb = 30 ° to 55 °, θt <
Let θb be the angle between the chord line of the blade and the straight line that is parallel to the rotation axis and that passes through the leading edge of the blade in the above developed view and is ξ (ξ: stagger angle). Ξ = (ξt−ξb) × (R−Rb) / (Rt−R
b) + ξb (ξt: stagger angle ξ, ξ at the outer periphery of the blade
b: stagger angle at boss radius Rb), ξt
= 55 ° to 70 °, ξb = 40 ° to 65 °, ξt> ξb, and a projection view of the axial blower projected on a plane orthogonal to the rotation axis, a cylindrical surface having a boss radius Rb of the blade Let Pb be the center point of the chord line in the cross section when cut.
O ′, the rotation axis as the origin O, and the point O and Pb
In a coordinate system with the straight line connecting the O'point as the X axis, the center point of the chord line when the blade is cut along a cylindrical surface with an arbitrary radius R is PR
As O ′, when the angle between the straight line PRO′-O and the X-axis is δθ (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt− Rb) (Rt: blade outer radius, Rb: blade boss radius, δθ
t: angle formed by the straight line PtO'-O and the X-axis), and δθ
Further, t is set to 25 to 40 °, and the value of the chord chord ratio T / LO defined by the ratio of the blade chord length LO and the circumferential distance (pitch) between the blades T is T at each radius point. / LO = 1.
1 to 2.0, first, a blade shape 1O 'is formed, and in the above projection, a straight line 1ba connecting a point 1baO' on the blade leading edge portion at the boss radius Rb of the blade 1O 'and an origin O.
When the point when the O′-O is rotated about the origin O in the rotation direction by an angle δαb that is between 20 and 50 ° is taken as the blade leading edge boss extension end point 1bb ′, the blade has an arbitrary radius R In a developed view obtained by cutting the cross section into a two-dimensional plane by cutting it along the cylindrical surface of, the blade chord at the boss radius Rb is the same as that of the blade 10 and the warp angle θ and the stagger angle ξ are the same. 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 at this time, the difference being ΔLb, and the blade outer circumference radius And a chord length LS at a point 1bs on the blade leading edge 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 blade leading edge. Distribution is L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
(Rb ≦ R ≦ Rs), the blade shape is formed, so that the chord length is longer than that of the base blade 10 and the pressure rise on the blade surface is increased. At the edge of the edge portion near the boss portion, the flow is along the blade surface due to the vertical vortex generated by the wraparound of the flow from the pressure surface 9 to the negative pressure surface 8, and the suction flow is guided to this vertical vortex and is blown to the outside. As a result, the disturbance of the flow on the suction surface of the blade due to the separation of the suction flow near the blade front edge at the time of high pressure loss can be eliminated, and noise can be reduced, and the fan is forced to rise by strong wind such as typhoon. As a measure when rotating,
A part of the blade is thickened near the boss near the front edge of the blade and at the connection between the boss and the blade 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 portion of each portion is formed into a blade shape with a radius of R, 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 above invention. FIG. 95 is an explanatory diagram showing the outdoor unit 18 of the air conditioner in which the axial blower 20 having the blades 1 according to the above-described invention is incorporated. See also FIG.
6 is an explanatory view of a refrigeration cycle including the axial flow fan 20 of the present invention similarly. In FIG. 96, the flow of the refrigerant during cooling is indicated by the solid arrow, and the flow of the refrigerant during heating is indicated by the broken arrow. During heating, the refrigerant that has passed through the four-way valve 23 from the compressor 21 is condensed in the indoor heat exchanger 25, and flares 27,
The pressure is reduced at the throttle 29 via the extension pipe 28 and the flare valve 26, evaporated in the outdoor heat exchanger 24, and returned to the compressor. The outdoor unit heat exchanger 24 is exposed to changes in the outside air environment and is liable to form dew or frost. In addition, there are more machines that inhale dust and dirt around them. Dew or frost may adhere to the entire or part of the outdoor heat exchanger 24,
If some dust or the like is attached, the resistance of the air passage becomes excessive, resulting in a high pressure loss state. 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 a wide range of characteristics and can maintain low noise. Further, since it is possible to obtain a large air volume as compared with the conventional device, 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 therefore can be used even when the air passage resistance, that is, the pressure loss is large. Even in an air passage with low resistance, the wind can be taken in from the outside by the blade surface vortex, and a large amount of air can be output. Therefore, it is possible to obtain an axial blower that has a wide range of use with less stall as fan performance. Further, the axial blower according to the present invention can stably control the vortex by the shape of the blade, and since the vortex causes the flow of the wind to follow the blade surface, the turbulence of the flow on the pressure surface side of the next rotating blade is prevented. It can be prevented and noise can be reduced. Further, according to the present invention, an axial blower having good performance 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 drawings]

FIG. 1 is a perspective view of an axial blower according to a first embodiment of the invention.

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

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

FIG. 4 is a diagram of an axial-flow blower according to a first embodiment of the invention.
YY sectional view in

FIG. 5 is a diagram of an axial-flow blower according to a first embodiment of the invention.
XX cross section in FIG.

FIG. 6 is a graph showing the relationship between the flow coefficient φ, the specific noise Ks, and the pressure coefficient ψ of the axial blower according to the first embodiment of the invention and the conventional axial blower.

FIG. 7 is a perspective view of an axial blower according to a second embodiment of the invention.

FIG. 8 is a front view of an axial blower according to a second embodiment of the invention.

FIG. 9 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the second embodiment of the invention.

FIG. 10 is a sectional view taken along line YY in FIG. 9 of the axial flow fan according to the second embodiment of the invention.

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

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

FIG. 13 is a ratio Rs of an arbitrary radius Rs at a point 1bs on the blade leading edge, which is the apex of the triangular flat plate 7, to a blade outer peripheral radius Rt when the rotation angle β of the axial blower according to the second embodiment of the 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 when the arbitrary radius Rs / Rt of the axial flow fan according to the second embodiment of the invention is constant.

FIG. 15 is a ratio Rs of an arbitrary radius Rs at a point 1bs on the blade leading edge, which is the apex of the triangular flat plate 7, with respect to the blade outer peripheral radius Rt of the axial blower according to the second embodiment of the present invention.
/ Rt and the minimum specific noise Ksmin with respect to the rotation angle β when determining the apex at the boss radius Rb of the triangular flat plate 7.
Graph of

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

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

FIG. 18 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the third embodiment of the invention.

FIG. 19 is a sectional view taken along line XX in FIG. 18 of the axial-flow blower according to the third embodiment of the invention.

FIG. 20 is a ratio Rs of an arbitrary radius Rs at a point 1bs on the blade leading edge which is the apex of the triangular flat plate 7 to a blade outer peripheral radius Rt at a constant rotation angle β of the axial blower according to the third embodiment of the 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 when the arbitrary radius Rs / Rt of the axial flow fan according to the third embodiment of the present invention is constant.

FIG. 22 is a ratio Rs of an arbitrary radius Rs at a point 1bs on the blade leading edge which is the apex of the triangular flat plate 7 to the blade outer radius Rt of the axial flow fan according to the third embodiment of the invention.
/ Rt and graph of minimum specific noise against rotation angle β when determining apex at boss radius Rb of triangular flat plate 7

FIG. 23 is a perspective view of an axial flow fan according to a fourth embodiment of the invention.

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

FIG. 25 is a cross-sectional view taken along the line AA in FIG. 24 of the axial-flow blower according to the fourth embodiment of the invention.

FIG. 26 is a frequency characteristic diagram of an axial flow fan according to a fourth embodiment of the invention and a conventional axial flow fan.

FIG. 27 is a perspective view of an axial blower according to a fifth embodiment of the invention.

FIG. 28 is a front view of an axial flow fan according to a fifth embodiment of the invention.

FIG. 29 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the fifth embodiment of the invention.

30 is a cross-sectional view taken along line XX in FIG. 29 of the axial blower according to the fifth embodiment of the invention.

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

FIG. 32 is a flow coefficient φ, a specific noise Ks, and a pressure coefficient ψ of the axial flow fan according to the fourth embodiment of the invention and the conventional axial flow fan.
Graph showing the relationship

FIG. 33 is a perspective view of an axial blower according to a sixth embodiment of the invention.

FIG. 34 is a front view of an axial flow fan according to a sixth embodiment of the invention.

FIG. 35 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the sixth embodiment of the invention.

FIG. 36 is a cross-sectional view taken along line XX in FIG. 35 of the axial-flow blower according to the sixth embodiment of the invention.

FIG. 37 is a ratio Rs / R of the arbitrary radius Rs at the point 1bs on the blade leading edge portion to the blade outer peripheral radius Rt when the rotation angle β of the axial flow fan according to the sixth embodiment of the invention is constant.
Graph of minimum specific noise against t

FIG. 38 is a graph of the minimum specific noise with respect to the rotation angle β when the arbitrary radius Rs of the axial blower according to the sixth embodiment of the present invention is constant.

FIG. 39 is a ratio Rs / R of an arbitrary radius Rs to a blade outer radius Rt of an axial flow fan according to a sixth embodiment of the invention.
Graph of minimum specific noise for t and rotation angle β

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

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

FIG. 42 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the seventh embodiment of the invention.

43 is a cross-sectional view taken along the line AA in FIG. 42 of the axial blower according to the seventh embodiment of the present invention.

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

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

FIG. 46 is a graph of the maximum stress σ applied to the outer peripheral portion Rt of the axial flow fan according to the seventh embodiment of the invention and the radius RR of the R shape of the connecting portion of the blade leading edge portion and the boss portion with respect to this portion.

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

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

FIG. 49 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the eighth embodiment of the invention.

50 is a boss radius Rb of the blade of FIG. 49 according to the invention;
Development view obtained by cutting at the cylindrical surface of and developing the cross section into a two-dimensional plane

51 is a diagram showing a state of stable vertical vortices and flows in the XX cross section in FIG. 49 according to the invention.

FIG. 52 is a perspective view showing the flow on the suction side of the axial blower according to Example 8 of the invention.

FIG. 53 is a diagram showing a flow on the blade suction surface when the blade leading edge boss advance extension angle δαb of the axial blower according to Example 8 of the invention is large.

FIG. 54 is a radius Rs of the blade leading edge boss extension starting point 1bs on the blade leading edge of the axial blower according to the eighth embodiment of the invention;
Graph of minimum specific noise against αb

FIG. 55 is a diagram showing a blade leading edge boss extension starting point 1b with respect to the blade outer peripheral radius Rt when the blade leading edge boss advance extension angle δαb of the axial blower according to Example 8 of the invention is constant.
Graph of minimum specific noise against ratio Rs / Rt with radius Rs in s

[FIG. 56] A radius R at a blade leading edge boss extension starting point 1bs with respect to a blade leading edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial blower according to Example 8 of the invention.
Graph of minimum specific noise against ratio Rs / Rt with s

[FIG. 57] A radius R at a blade leading edge boss extension starting point 1bs with respect to a blade leading edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow fan according to an eighth embodiment of the invention.
The maximum stress σ on the blade with respect to the ratio Rs / Rt with s
Graph of

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

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

FIG. 60 is a projection view of the blades projected onto a plane orthogonal to the rotation axis of the axial flow fan according to the ninth embodiment of the invention.

61 is a boss radius Rb of the blade of FIG. 60 according to the invention;
Development view obtained by cutting at the cylindrical surface of and developing the cross section into a two-dimensional plane

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

FIG. 63 is a perspective view showing the flow on the suction side of the axial blower according to Example 9 of the invention.

64 is a diagram showing the axial extension fan according to the ninth embodiment of the invention, which corresponds to FIG. 61 and corresponds to FIG. 61.
Diagram showing flow on suction side when αb is too large

FIG. 65 is an all-round development view 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 Example 9 of the present 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 ψ of the axial blower according to the ninth embodiment of the invention and the axial blower having the blades that are the bases of the blades of the axial blower of the ninth embodiment. Figure

FIG. 67 is a radius Rs of a blade leading edge boss extension starting point 1bs on a blade leading edge of an axial blower according to Example 9 according to the invention, where the blade leading edge boss advance extension angle δ at a constant time.
Graph of minimum specific noise against αb

FIG. 68 is a blade leading edge boss extension starting point 1b relative to the blade outer peripheral radius Rt when the blade leading edge boss advance extension angle δαb of the axial blower according to Example 9 of the invention is constant.
Graph of minimum specific noise against ratio Rs / Rt with radius Rs in s

FIG. 69 is a radius R at a blade leading edge boss extension starting point 1bs relative to a blade leading edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial blower according to Example 9 of the invention.
Graph of minimum specific noise against ratio Rs / Rt with s

[FIG. 70] A radius R at a blade leading edge boss extension starting point 1bs relative to a blade leading edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial-flow blower according to Embodiment 9 of the present invention.
The maximum stress σ on the blade with respect to the ratio Rs / Rt with s
Graph of

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

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

FIG. 73 is a projection view of the blades projected on a plane orthogonal to the rotation axis of the axial flow fan according to the tenth embodiment of the invention.

FIG. 74 is a development view obtained by cutting the blade of the axial 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. 75 is a view showing a flow in the XX cross section of FIG. 73 of the axial blower according to the tenth embodiment of the invention.

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

77 is a view showing a flow on the blade suction surface when the blade leading edge boss advance extension angle δαb of the axial blower according to Example 10 of the invention is large. FIG.

FIG. 78 is a minimum specific noise with respect to the blade leading edge boss advance extension angle δαb when the radius Rs at the blade leading edge boss extension start point 1bs on the blade leading edge of the axial flow fan according to the tenth embodiment of the invention is constant. Graph of

FIG. 79 is a diagram illustrating a blade leading edge boss extension starting point 1 with respect to a blade outer peripheral radius Rt when the blade leading edge boss advance extension angle δαb of the axial blower according to the tenth embodiment of the present invention is constant.
Graph of minimum specific noise against ratio Rs / Rt with radius Rs in bs

FIG. 80 is a diagram illustrating a blade front edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow fan according to a tenth embodiment of the invention.
Of the minimum specific noise against the ratio Rs / Rt with the radius Rs at the blade leading edge boss extension starting point 1bs for

81] A blade front edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow fan according to a tenth embodiment of the present invention.
Of the maximum stress σ applied to the blade with respect to the ratio Rs / Rt with the radius Rs at the blade leading edge boss extension starting point 1bs

FIG. 82 is a perspective view of an axial blower according to an eleventh embodiment of the invention.

FIG. 83 is a front view of an axial blower according to an eleventh embodiment of the invention.

FIG. 84 is a projection view when the blades are projected on a plane orthogonal to the rotation axis of the axial flow fan according to the eleventh embodiment of the invention.

FIG. 85 is a development view obtained by cutting the blade of the axial-flow blower according to the eleventh embodiment of the invention with a cylindrical surface having a boss radius Rb and developing the cross section into a two-dimensional plane.

FIG. 86 is a view showing the flow in the YY cross section of FIG. 84 of the axial blower according to the eleventh embodiment of the invention.

FIG. 87 is a perspective view showing the flow on the suction side of the axial blower according to Example 11 of the invention.

88 is a view showing the flow on the suction surface when the blade leading edge boss advance extension angle δαb in the diagram corresponding to FIG. 85 of the axial blower according to the eleventh embodiment of the invention is too large.

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

FIG. 90 shows the relationship between the flow coefficient φ, the specific noise Ks, and the pressure coefficient ψ of the axial blower according to the eleventh embodiment of the present invention and the axial blower having the blades that are the bases of the blades of the axial blower of the eleventh embodiment. Figure

FIG. 91 is a minimum specific noise with respect to a blade leading edge boss advance extension angle δαb when a radius Rs at a blade leading edge boss extension start point 1bs on a blade leading edge of an axial blower according to Example 11 according to the invention is constant. Graph of

FIG. 92 is a diagram showing a blade leading edge boss extension start point 1 with respect to a blade outer peripheral radius Rt when the blade leading edge boss advance extension angle δαb of the axial blower according to the eleventh embodiment of the invention is constant.
Graph of minimum specific noise against ratio Rs / Rt with radius Rs in bs

FIG. 93 is a diagram showing a blade front edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow fan according to an eleventh embodiment of the invention;
Of the minimum specific noise against the ratio Rs / Rt with the radius Rs at the blade leading edge boss extension starting point 1bs for

FIG. 94 is a diagram showing a blade leading edge boss advance extension angle δαb and a blade outer peripheral radius Rt of an axial flow fan according to an eleventh embodiment of the invention;
Of the maximum stress σ applied to the blade with respect to the ratio Rs / Rt with the radius Rs at the blade leading edge boss extension starting point 1bs

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 diagram of a refrigeration cycle according to the invention.

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

FIG. 98 is a projection diagram when the blades are projected on a plane orthogonal to the rotation axis of the conventional axial flow fan.

FIG. 99 is a center point P of a chord line of blades of a conventional axial-flow blower.
Radial distribution of W and sectional view at the same position of the blade

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

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

102 is a view of a conventional axial-flow blower according to the invention, FIG.
Showing the flow on the blade suction surface at the time of high pressure loss in the AA cross section in FIG.

103 is a B- in FIG. 97 of the conventional axial blower.
The figure which showed the flow on the blade front edge part and the blade suction surface in the part where the blade plate thickness is thick near the boss part of the blade front edge part in the B section.

[Explanation of symbols]

1. Feather 1O. Base blade 1 '. Blade in projection view 1O'. Base blade in projection view 1a. Blade tip 1a '. Blade tip 1aO' in projection view Blade tip of base blade in projection 1b. Blade leading edge 1bO. Blade front edge of base blade 1baO. A point at the boss radius of the blade leading edge of the base blade 1b '. A blade leading edge 1bO' in the projected view. A blade leading edge 1baO 'of the base blade in the projected view. Point at the boss radius of the blade leading edge 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. Blade trailing edge 1CO '. Blade trailing edge 1cb '. Point on boss radius on blade trailing edge in projection 1d. Blade outer peripheral portion 1 dO. Outer peripheral portion of base blade 1d '. Peripheral portion of blade in projection view 1dO '. The outer peripheral portion of the base blade in the projected view 1. Boss 3. Rotation axis 4. Direction of rotation 5. Sled line 6. Parallel axis of rotation 7. Triangular plate cut 7 '. Triangular flat plate in projection diagram 8. Blade suction surface 8N. Blade negative pressure surface of next rotating blade 9. Blade pressure surface 9N. Vane pressure surface of the next swirling blade 10. Longitudinal vortices generated in the portion of the blade leading edge near the boss 11. Flow on blade suction surface 12. Flow of suction of blades 13. Flow on blade pressure surface 14. Insertion direction of triangular flat plate 15. Insertion jig for triangular flat plate 16. Vortex in the outer peripheral portion of the 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 2-3-3 Marunouchi, Chiyoda-ku, Tokyo Sanryo Electric Co., Ltd.

Claims (18)

[Claims] 1. A periphery is constituted by a blade front edge portion which is attached to a rotating boss portion and faces the rotation direction, a blade trailing edge portion which faces the direction opposite to the rotation direction, and a blade outer peripheral portion which faces the boss portion. And one side along the boss portion of the blade leading edge portion and the other side along the outer circumference of the boss portion adjacent to the blade leading edge portion, and at least the blade leading edge. An axial-flow blower, comprising: a plate-shaped member having a thickness substantially equal to the blade thickness, the plate-shaped member being attached to one of the blade portion and the boss portion and integrally formed with the blade. 2. An origin O is the center of rotation, and a radius O-1bs 'with a point 1bs' on the blade leading edge at an arbitrary radius.
1 bb 'is the intersection with the outer circumference of the boss when the is rotated by an angle β in the rotation direction, and the plate-like member has a substantially triangular shape so as to pass through the above 1bs' and 1bb'. The axial blower according to claim 1. 3. An origin O is the axis of rotation, and a radius O-1bs 'with a point 1bs' on the blade leading edge portion at an arbitrary radius.
When the other side of the plate member is arranged between the blade front edge portion and this 1bb ′, the intersection point with the outer circumference of the boss portion when the blade is rotated by the angle β in the rotation direction is 1bb ′. 10
The axial blower according to claim 1, wherein the axial blower is selected to be -40 degrees. 4. An origin O is the axis of rotation, a point 1bs 'on the blade leading edge portion at an arbitrary radius, a blade outer peripheral radius is Rt, and one side of the plate member is 1bs' of the blade leading edge portion.
The axial blower according to claim 1, wherein a radius O-1bs' is selected to be 40% to 75% of the outer peripheral radius Rt of the blade when the blade is disposed between the blade and the boss. 5. The axial blower according to claim 1, wherein the plate-shaped member is attached to the front edge of the blade so as to be in close contact with the blade from the rotational direction. 6. A periphery is constituted by a blade front edge portion which is attached to a rotating boss portion and faces the rotation direction, a blade rear edge portion which faces the direction opposite to the rotation direction, and a blade outer peripheral portion which faces the boss portion. And one side along the boss portion of the blade leading edge portion and the other side along the outer circumference of the boss portion adjacent to the blade leading edge portion, and at least the blade leading edge. Is a plate-shaped member attached to either one of the boss and the boss and formed integrally with the blade, and having a thickness substantially equal to the blade thickness, wherein the axis O of rotation is the origin O, and the above is set at an arbitrary radius. The point 1bs' on the leading edge of the blade is defined as the point 1bs', and the intersection point with the outer circumference of the boss when the radius O-1bs' between the point 1bs' and the origin O is rotated by an angle β in the rotation direction is defined as 1bb '. A plate-like member that passes through'and 1bb ', The angle β is selected to be 10 to 40 degrees, and the radius O-1bs ′ is 40 to 75% of the blade outer peripheral radius Rt.
An axial blower characterized by being selected for. 7. A periphery is constituted by a blade front edge portion facing the rotation direction, attached to a rotating boss portion, a blade rear edge portion facing in the direction opposite to the rotation direction, and a blade outer peripheral portion facing the boss portion. On the outer circumference of the boss when the radius O-1bs 'between the blade to be rotated and the axis O of the rotation is the origin O and the point 1bs' on the blade leading edge at an arbitrary radius is rotated by the angle β in the rotation direction. And a blade shape in which the portion near the boss portion of the blade leading edge portion is extended in the rotational direction in a shape that passes through 1bs ′ and 1bb ′, and the angle β The axial-flow blower is characterized by selecting 10 to 40 degrees. 8. The radius O-1bs' is defined as the blade outer peripheral radius Rt.
The axial flow fan according to claim 7, wherein the axial flow fan is selected from 40 to 75%. 9. The axial blower according to claim 2, wherein the blade has a plurality of blades whose angle β is changed with respect to each blade. 10. A plurality of blades having a radius O-1bs' varied with respect to each blade, wherein the blade has a plurality of blades.
Axial blower according to item. 11. A blade shape obtained by extending a portion from a boss portion of a blade front edge portion in a rotational direction is connected to a tangent line at 1bs 'and 1bb' by a curved line which is concave with respect to the rotational direction, and the blade leading edge portion is formed. The axial blower according to claim 2, 3 or 4, 6 or 7 or 8, wherein the axial blower is formed as follows. 12. A blade leading edge portion is formed by connecting a connecting portion between the blade leading edge portion and a boss portion with a curve that is concave with respect to a rotation direction having a radius of 15 to 35% of a radius of the blade outer peripheral portion. The axial flow fan according to any one of claims 1 to 11, wherein the blade shape is formed as follows. 13. A boss part which is attached with blades and rotates,
A blade whose front edge is facing the rotation direction, a blade trailing edge which faces the direction opposite to the rotation direction, and a blade outer circumference which faces the boss, and a circumference of which is defined as an origin O. , A boss that is the radius of the boss and the straight line 1bs'-O when the straight line 1bs'-O connecting the origin O and the arbitrary point 1bs' on the blade leading edge is rotated in the rotation direction about the origin O. The axial flow fan is characterized in that the tangent line at the intersection point 1bb 'with the side surface of the part and the tangent point at the point 1bs' are connected to each other by an arbitrary curve that is concave with respect to the rotation direction to form a blade leading edge portion. . 14. A straight line 1baO'-O connecting a point 1baO 'on the front edge of the blade at the base of the blade and the origin O is defined as an origin O with respect to the origin O as the center of rotation, and 2 in the direction of rotation about the origin O.
A point 1bb ′ of the boss radius Rb when rotated by an angle δαb between 0 and 50 ° and a blade outer peripheral radius of 40 to 70.
The shape between points 1bs ′ on the blade leading edge having a radius Rs of% is defined from the point 1ba ′ on the blade leading edge which is the boss radius Rb of the blade with the blade leading edge as a reference. The boss radius R 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.
The radial direction distribution of δα, which represents the angle between the straight line 1bC′-O connecting the point 1bC ′ of the radius Rc between the radius b and the radius Rs and the origin O, is δα = (δαb / (Rb- RS) 2) x (R-RS) 2
(Rb ≦ R ≦ Rs) and the blade shape is formed by extending the blade front edge portion near the boss portion in the rotation direction from the point 1bs ′ on the blade front edge portion so as to be continuous with the blade. Claim 1 characterized by the above-mentioned.
The axial blower described in 3. 15. A straight line 1baO′-O that connects the origin O with a point 1baO ′ on the blade leading edge portion at the boss radius Rb of the blade 1O ′ of the base is defined as the origin O, and the origin O is defined as the origin O. An angle δ centered in the direction of rotation between 20 and 50 °
The point when rotated by αb is the end point 1b of the blade front edge boss extension.
b ′, the blade is cut by a cylindrical surface with an arbitrary radius R,
In a development view obtained by developing the cross section into a two-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 ξ. At this time, the blade 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 portion 1Cb, which is ΔLb, is 4 times the blade outer peripheral radius.
Radius distribution of the chord length L from the boss radius Rb to the point 1bs on the vane leading edge, where the chord length LS at the point 1bs on the vane leading edge is 0 to 60%. L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
The blade shape is formed by providing (Rb ≦ R ≦ Rs).
The axial blower described in 3. 16. In a developed view obtained by cutting a blade of an axial blower with a cylindrical surface having an arbitrary radius R and developing the cross section into a two-dimensional plane, the shape of the warp line in the cross section of the blade is an arc shape. 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: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θ
b = 30 ° to 55 °, θt <θb, and in the above developed view, the angle between the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge of the blade is ξ (ξ:
Stagger angle), the radial distribution of ξ is ξ =
(Ξt−ξb) × (R−Rb) / (Rt−Rb) + ξb
(Ξt: stagger angle ξ at blade outer periphery, ξb: stagger angle at boss radius Rb), ξt = 55 ° to 7
0 °, ξb = 40 ° to 65 °, ξt> ξb, and a chord ratio T / L defined by the ratio of the chord length L and the circumferential distance (pitch) T between the blades. The value is T / L = 1.1 to 2.0 at each radius point, and in a projection view in which the axial blower is projected on a plane orthogonal to the rotation axis, a cylindrical surface having a boss radius Rb of the blade is used. The blade chord line center point in the cross section when cut is Pb ′, the rotation axis is the origin O, and the straight line connecting the point O and Pb ′ is the X axis in a coordinate system, and the blades have an arbitrary radius R. Let PR ′ be the center point of the chord line when cut along the cylindrical surface of the above, and the angle between the straight line PR′−O and the X axis is δθ (δ
(θ: advance angle in rotation direction), the radial distribution of δθ is δθ = δθt × (R-Rb) / (Rt-Rb) (Rt: blade outer peripheral radius, Rb: blade boss radius, δθ
t: angle formed by 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 a point 1ba ′ on the blade leading edge portion of the blade root and an origin O at this time is rotated about the origin O. To 2
A point 1bb ′ of the boss radius Rb when rotated by an angle δαb between 0 and 50 ° and a blade outer peripheral radius of 40 to 70.
The shape between points 1bs ′ on the blade leading edge having a radius Rs of% is defined from the point 1ba ′ on the blade leading edge which is the boss radius Rb of the blade with the blade leading edge as a reference. The boss radius R 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.
The radial direction distribution of δα, which represents the angle between the straight line 1bC′-O connecting the point 1bC ′ of the radius Rc between the radius b and the radius Rs and the origin O, is δα = (δαb / (Rb- RS) 2) x (R-RS) 2
(Rb ≦ R ≦ Rs) and the blade shape is formed by extending the blade front edge portion near the boss portion in the rotation direction from the point 1bs ′ on the blade front edge portion so as to be continuous with the blade. Claim 1 characterized by the above-mentioned.
The axial blower described in 3. 17. A development view obtained by cutting a blade of an axial blower with a cylindrical surface having an arbitrary radius R and developing the cross section into a two-dimensional plane, wherein the shape of the warp line in the blade cross section is an arc shape, 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: warp angle at blade outer periphery, θb: warp angle at blade boss radius Rb), θt = 25 ° to 35 °, θ
b = 30 ° to 55 °, θt <θb, and in the above developed view, the angle between the chord line of the blade and the straight line parallel to the rotation axis and passing through the leading edge of the blade is ξ (ξ:
Stagger angle), the radial distribution of ξ is ξ =
(Ξt−ξb) × (R−Rb) / (Rt−Rb) + ξb
(Ξt: stagger angle ξ at blade outer periphery, ξb: stagger angle at boss radius Rb), ξt = 55 ° to 7
In a projection view in which 0 °, ξb = 40 ° to 65 °, ξt> ξb are set, and an axial blower is projected on a plane orthogonal to the rotation axis, the blade is cut by a cylindrical surface having a boss radius Rb. The center point of the chord line in the cross section is PbO ′, the rotation axis is the origin O, and the straight line connecting the point O and the point PbO ′ is the X axis, and the blade is a cylindrical surface with an arbitrary radius R. Let PRO 'be the center point of the chord line when cut, and the angle between the straight line PRO'-O and the X axis is δθ.
When (δθ: forward angle of rotation), the radial distribution of δθ is δθ = δθt × (R−Rb) / (Rt−Rb) (Rt: blade outer peripheral radius, Rb: blade boss radius, δθ
t: angle formed by the straight line PtO'-O and the X-axis), and δθ
t is 25 to 40 °, and the chord length LO is the circumferential distance (pitch) between the blades.
The value of the chordal ratio T / LO defined by the ratio with T is set to T / LO = 1.1 to 2.0 at each radius point, and first, the blade shape 1O ′ is formed. , A straight line 1baO′-O that connects the origin O with the point 1baO ′ on the blade leading edge portion at the boss radius Rb of the blade 1O ′ is 20 to 5 in the rotation direction about the origin O.
When the point when rotated by an angle δαb that is between 0 ° is the blade leading edge boss extension end point 1bb ′, the blade is cut with a cylindrical surface of an arbitrary radius R and its cross section is developed into a two-dimensional plane. In the developed view obtained as above, the chord at the boss radius Rb is the same as that of the blade 1O with the same deflection angle θ and stagger angle ξ.
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, which is ΔLb, is defined as ΔLb. Letting the chord length LS at the point 1bs on the blade leading edge at a radius Rs of 40 to 60% of the radius, the chord length L from the boss radius Rb to the point 1bs on the blade leading edge.
The radial distribution of L = ΔLb / (Rs−Rb) 2 × (R−Rs) 2 + LS
The blade shape is formed by providing (Rb ≦ R ≦ Rs).
The axial blower described in 3. 18. An air conditioner using the axial blower according to any one of claims 1 to 17.