JP2002257088A - Axial flow fan - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial flow fan capable of reducing blade area without complicating a shape of a blade trailing edge part, improving a forming property and reducing cost, and saving energy by maintaining a load on a driving motor low when rotation speed is increased to increase the quantity of air flow. SOLUTION: In an axial flow fan provided with plural blades 2 along a circumference surface of a cylindrical boss hub 1 and sending air in an axial direction with rotation thereof, the blade is provided with the blade trailing edge part 2c in an air flowing out direction, a blade leading edge part 2b in an air inlet direction, and a blade outer circumference part 2d forming an outer circumference. A contour α of the blade trailing edge part 2c is formed in a reversed arch shape recessing in the air inlet direction opposite to the air flow-out direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial fan which has a plurality of blades along a peripheral surface of a cylindrical boss hub and blows air in an axial direction with rotation.

[0002]

2. Description of the Related Art There are various types of fans for a blower. Among them, there is an axial fan that blows air sucked from the axial direction of the fan in the axial direction. The blower provided with the axial fan is disposed, for example, in an outdoor unit constituting an air conditioner, and has a function of blowing outside air to the outdoor heat exchanger.

[0003] The structure of the blower comprises a drive motor mounted and fixed to a gantry, and an axial fan fitted to a rotating shaft of the drive motor. By selecting this axial fan, the outdoor unit can be made thinner and the heat exchange efficiency for the heat exchanger can be ensured.

[0004]

FIG. 9 shows a configuration of a conventional axial fan. A plurality of blades 2A (only one blade is shown in the figure) are provided at predetermined intervals along the peripheral surface of the cylindrical boss hub 1.

A portion of the blade 2A integrally connected to the boss hub 1 is referred to as a root portion a, and when the rotation direction is clockwise, a front side of rotation is referred to as a blade front edge portion b, and a rear side of the blade is a rear portion of the blade. The outer edge of the leading edge b and the trailing edge c of the blade
An end portion connecting the outer peripheral ends is referred to as a blade outer peripheral portion d.

The air is blown in the axial direction with the rotation of the axial fan. The leading edge b of the blade is in the air introduction direction, and the trailing edge c is in the air outflow direction. As a structural feature, the tip b1 of the blade leading edge b protrudes more in the rotation direction than the rotation-side end of the root a, while the contour c1 of the blade trailing edge c is orthogonal to the rotation direction. It is formed linearly in the direction.

For this reason, the rigidity and noise reduction at the tip b1 of the blade leading edge b can be obtained. However, at the blade trailing edge c, when the rotational speed of the axial fan is increased to increase the air volume. In addition, since the contour c1 of the trailing edge c of the blade is substantially linear, the wake vortex, that is, the flow of the air flow along the pressure surface and the suction surface of the blade collides at the downstream portion of the trailing edge of the blade. As a result, the vortex generated is large, the flow loss increases, and the load on the drive motor constituting the blower increases.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to make it possible to form a small blade area without complicating the shape of the trailing edge of the blade, thereby improving the formability. The aim is to provide an axial fan that can reduce the load on the drive motor and increase energy savings when increasing the number of revolutions and increasing the air flow by reducing the cost. is there.

[0009]

According to a first aspect of the present invention, a plurality of blades are provided along the peripheral surface of a cylindrical boss hub. In the axial flow fan that blows air in the airflow direction, the blade includes a blade trailing edge in an air outflow direction, a blade leading edge in an air introduction direction, and a blade outer peripheral portion forming an outer periphery. The contour of the edge portion is characterized in that it is formed in an inverted arc-shaped concave shape that is depressed in the introduction direction opposite to the air outflow direction.

According to a second aspect of the present invention, in the axial flow fan according to the first aspect, the inverted arc shape forming the contour of the trailing edge of the blade is 1
It is characterized in that it is formed from two curves, or two curves with different curvatures are formed continuously.

According to a third aspect of the present invention, in the axial flow fan according to the first aspect, the center of rotation of the fan O, the contour α of the blade trailing edge, and the outer peripheral portion of the blade are defined with respect to a plane perpendicular to the fan rotation axis. A line connecting an intersection point Q with the contour line β is defined as OQ, a line connecting an intersection S between the fan rotation center point O, the contour line γ of the blade leading edge, and the contour line β of the blade outer peripheral portion is defined as OS, OQ and O above
Suppose that the angle formed with S is θt, and that the line segments respectively connected from the inverted arc-shaped center point P of the contour line of the trailing edge of the blade to the two inverted arc-shaped end points G1 and G2 are PG1 and PG2, respectively. The angle θk between the segment PG1 and the line segment PG2 is the angle θt
Is set to be 0.7 to 0.8 times as large as.

According to a fourth aspect of the present invention, in the axial flow fan according to the second aspect, the inverted arc shape defining the contour of the trailing edge of the blade is 2
Are formed from two curves having different curvatures, each of the arc-shaped center points is defined as T, U, and each of the arc-shaped end points is defined as J1, J.
2, J3, the angle θt between the OQ and the OS
Is an angle θm between a line segment TJ1 connecting the center point T and the end point J1, a line segment TJ2 connecting the center point T and the end point J2,
1.3 to 1.5 with respect to the angle (θm + θn) obtained by adding the line segment UJ2 connecting the center point U and the end point J2 and the angle θn formed by the line segment UJ3 connecting the center point U and the end point J3. The size is set to be twice as large.

According to a fifth aspect of the present invention, there is provided a cylindrical boss hub, wherein a plurality of blades are provided along the peripheral surface of the cylindrical boss hub. In the fan, the blade includes a wing trailing edge in an air outflow direction, a wing leading edge in an air introduction direction, and a wing outer peripheral portion forming an outer periphery.The contour of the wing trailing edge is Are formed in a substantially V-shaped concave shape that is recessed in an introduction direction opposite to the air outflow direction.

According to a sixth aspect of the present invention, in order to satisfy the above object, a plurality of blades as blades are provided along a peripheral surface of a cylindrical boss hub, and an axial flow blows in an axial direction as the blade rotates. In the fan, the blade includes a wing trailing edge in an air outflow direction, a wing leading edge in an air introduction direction, and a wing outer peripheral portion forming an outer periphery.The contour of the wing trailing edge is It is characterized in that it is formed in a substantially trapezoidal concave shape that is recessed in an introduction direction opposite to an air outflow direction.

[0015] Claim 7 is Claim 1 to Claim 6
In the axial flow fan according to any of the above, the intersection of the contour α of the blade trailing edge and the contour β of the blade outer peripheral portion is Q,
The intersection point between the contour line γ of the blade leading edge and the contour line β of the blade outer peripheral portion is S, the plane perpendicular to the fan rotation axis Y passing through the intersection Q is QY, and the plane perpendicular to the fan rotation axis Y passing through the intersection S. Assuming that the plane is SY, the plane QY and the contour α of the trailing edge of the wing with respect to the vertical line Hf extending between the plane QY and the plane SY.
The vertical maximum distance Hk is set to be in a range of 10 to 20%.

[0018] Claim 8 is Claim 1 to Claim 7
In the axial flow fan according to any one of the above, the contour line of the trailing edge portion of the blade is formed of the concave portion and the inner and outer peripheral sides of the fan.
The shoulders formed at two locations are connected to each other, and when the shoulder length on the inner peripheral side is L1 and the shoulder length on the outer peripheral side is L2, L1 ≧ L2 is set. It is characterized by.

According to the first to eighth aspects of the present invention, by adopting means for solving the above problems,
Even when the fan speed is increased and the air volume is increased, the load on the motor can be kept small, so energy saving can be improved and the blades can be made without complicating the shape of the trailing edge. The area can be reduced, and the moldability can be improved and the cost can be reduced.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram of the axial fan as viewed from the blade pressure surface side, and FIG. 2 is a diagram of a part of the fan as viewed from the blade pressure surface side, and illustrates the first embodiment. is there. That is, as a basic configuration of the axial flow fan, a plurality of (here, three) blades 2 as blades are integrally provided at a predetermined interval on a peripheral surface of the cylindrical boss hub 1, and the rotation of the fan is performed. As a result, the air is blown in the axial direction.

The portion of the blade 2 integrally connected to the boss hub 1 is referred to as a root portion 2a.
b, the rotating side is referred to as a wing trailing edge 2c, and the end connecting the outer edge of the wing leading edge 2b and the outer edge of the wing trailing edge 2c is referred to as a wing outer edge 2d.

Further, the blade 2 is rotated by the rotation of the fan.
On the basis of the air flow above, the leading edge 2b of the blade is in the air introduction direction, and the trailing edge 2c of the blade is in the air outflow direction. There is no change in that the tip of the wing leading edge 2b protrudes more in the rotation direction than the rotation-side end of the root 2a.

In particular, the contour forming the leading edge 2b of the blade is γ, the contour forming the trailing edge 2c is α, and the outer periphery 2d of the blade.
Is defined as β, the characteristic feature here is that the contour α forming the wing trailing edge portion 2c is recessed in the introduction direction opposite to the air outflow direction, and has an inverted arc shape. That is, it is formed in a concave shape.

The inverted arc shape forming the contour α of the blade trailing edge portion 2c is formed from one curve in the figure. Note that the present invention is not limited to this, and two curves having different curvatures may be continuously formed.

When the axial flow fan provided with the blade 2 having the contour α of the blade trailing edge 2c formed in an inverted arc shape is rotationally driven, even when the rotational speed is increased to increase the air volume, The wake vortex becomes smaller, the loss of air flow is reduced, the load on the drive motor can be reduced, and the energy saving of the air conditioner is improved.

FIG. 3 is a view of a part of the axial fan as viewed from the blade pressure side, and illustrates the second embodiment. That is, when the axial fan is viewed from a plane perpendicular to the rotation axis, a line connecting the intersection Q of the rotation center point O, the contour α of the blade trailing edge 2c, and the contour β of the blade outer peripheral portion 2d is represented by OQ. And In addition, a line connecting the intersection S of the rotation center point O, the contour line γ of the blade leading edge 2b, and the contour line β of the blade outer peripheral portion 2d is defined as OS. An angle between the line segment OQ and the line segment OS is defined as θt.

Further, from the inverted arc-shaped center point P forming the contour line α of the blade trailing edge 2c, two inverted arc-shaped end points G1,
Line segments connected to G2 are referred to as PG1 and PG2, respectively. The angle θk between these line segments PG1 and PG2
Is set to be 0.7 to 0.8 times the angle θt. As a result, the wake vortex of the blade becomes smaller, and the load applied to the drive motor can be reduced.

FIG. 4 is a view of a part of the axial fan as viewed from the blade pressure side, and illustrates the third embodiment. That is, although the contour α of the wing trailing edge 2c is still in the shape of an inverted arc, here, the contour is formed by two curves having different curvatures.

The rotation center point O and the contour α of the wing trailing edge 2c
OQ is the line connecting the intersection Q between the
An angle formed by the line segment OQ and the line segment OS is a line connecting the intersection S of the rotation center point O, the contour line γ of the blade leading edge portion 2b, and the contour line β of the blade outer peripheral portion 2d as OS. Is θt.

Then, each arc-shaped center point is defined as T, U from the blade outer periphery 2d side, and each inverted arc-shaped end point is defined as J1, J2, J3 from the blade outer periphery side. θt is the angle θ obtained by adding the angle θm formed by the line segment TJ1 and the line segment TJ2 and the angle θn formed by the line segment UJ2 and the line segment UJ3.
It was set to be 1.3 to 1.5 times the size of m + n. As a result, the wake vortex of the blade becomes smaller, and the load applied to the drive motor can be reduced.

FIG. 5 is an external view of a part of the axial flow fan as viewed from the blade negative pressure surface side, and illustrates the fourth embodiment. That is, assuming that the contour α of the wing trailing edge 2c is formed in an inverted arc shape, the intersection of the contour α and the contour β forming the wing outer peripheral portion 2d is Q, and The intersection point of the contour line γ of the edge 2b and the contour line β of the blade outer peripheral portion 2d is defined as S. A plane passing through the intersection Q and perpendicular to the fan rotation axis Y is denoted by QY, and a plane passing through the intersection S and perpendicular to the fan rotation axis Y is denoted by SY.

At this time, a vertical line H between the plane QY and the plane SY
f, the plane QY and the contour αa of the wing trailing edge 2c
The vertical maximum distance Hk up to the range is set to be in the range of 10 to 20%. As a result, the wake vortex of the blade becomes smaller, and the load applied to the drive motor can be reduced.

FIG. 6 is a view of a part of the axial fan as viewed from the blade pressure side, and illustrates the fifth embodiment. That is, the contour line α forming the wing trailing edge 2c
Is composed of an inverted arcuate portion α1 and two curved portions α2 and α3 on the inner and outer sides of the fan, which constitute both sides of the inverted arcuate portion.

When the length of the curved portion α2 on the inner peripheral side is L1 and the length of the curved portion α3 on the outer peripheral side is L2,
It was set so that 1 ≧ L2. As a result, the wake vortex of the blade becomes smaller, and the load applied to the drive motor can be reduced.

FIG. 7 is a view of a part of the axial fan as viewed from the blade pressure side, and illustrates the sixth embodiment. That is, an axial fan is provided with a plurality of blades 2 (here, only one blade is shown) along the peripheral surface of a cylindrical boss hub 1 and blowing air in the axial direction with the rotation thereof.

The blade 2 has a blade leading edge 2b in the air introduction direction and a blade trailing edge 2c in the air outflow direction.
And a blade outer peripheral portion 2d forming the outer periphery, and respective contour lines are referred to as γ, αa, and β. The feature here is that the contour line αa of the wing trailing edge 2c is formed in a substantially V-shaped concave shape that is recessed in the introduction direction opposite to the air outflow direction. Even with such a shape, an effect equivalent to that of the inverted arc shape can be obtained.

FIG. 8 is a view of a part of the axial fan as viewed from the blade pressure side, and illustrates the seventh embodiment. That is, an axial fan is provided with a plurality of blades 2 (here, only one blade is shown) along the peripheral surface of a cylindrical boss hub 1 and blowing air in the axial direction with the rotation thereof.

The blade 2 has a blade leading edge 2b in the air introduction direction and a blade trailing edge 2c in the air outflow direction.
And a blade outer peripheral portion 2d forming the outer periphery, and respective contour lines are referred to as γ, αb, and β. The feature here is that the contour line αb of the wing trailing edge 2c is formed in a trapezoidal concave shape that is recessed in the introduction direction opposite to the air outflow direction. Even with such a shape, an effect equivalent to that of the inverted arc shape can be obtained.

[0037]

As described above, according to the present invention, regardless of the configuration of the axial fan, the load applied to the drive motor is increased even when the fan speed is increased to increase the air flow. The size of the blade can be kept small, so that energy saving can be improved, and the blade area can be reduced without complicating the shape of the trailing edge of the blade. This has the effect of improving moldability and reducing costs. .

[Brief description of the drawings]

FIG. 1 is an external view of an entire axial flow fan as viewed from a blade pressure side, showing a first embodiment of the present invention.

FIG. 2 is an external view of a part of the axial flow fan as viewed from the blade pressure side, showing the embodiment.

FIG. 3 is an external view of a part of an axial fan as viewed from a blade pressure side according to a second embodiment of the present invention.

FIG. 4 is an external view of a part of an axial fan viewed from a blade pressure side according to a third embodiment of the present invention.

FIG. 5 is an external view of a part of an axial fan as viewed from a negative pressure side, showing a fourth embodiment of the present invention.

FIG. 6 is an external view of a part of an axial fan as viewed from a blade pressure side according to a fifth embodiment of the present invention.

FIG. 7 is an external view of a part of an axial fan as viewed from a blade pressure side according to a sixth embodiment of the present invention.

FIG. 8 is an external view of a part of an axial fan as viewed from a blade pressure side according to a seventh embodiment of the present invention.

FIG. 9 is an external view of a part of a conventional axial flow fan viewed from a blade pressure side.

[Explanation of symbols]

 1 ... boss hub, 2 ... blade (wing), 2c ... wing trailing edge, α, αa, αb ... contour line (of wing trailing edge), 2b ... wing leading edge, γ ... (of wing leading edge) Contour line, 2d ... blade outer periphery, β ... contour line (of blade outer periphery).

Claims (8)

[Claims] 1. An axial flow fan, wherein a plurality of blades are provided along a peripheral surface of a cylindrical boss hub, and the blades blow in the axial direction with the rotation of the blades. A wing trailing edge portion, a wing leading edge portion in the air introduction direction, and a wing outer peripheral portion forming an outer periphery. The contour of the wing trailing edge portion is an introduction direction opposite to the air outflow direction. An axial flow fan characterized by being formed in an inverted arc-shaped concave shape that is recessed into the fan. 2. The inverted arc forming the contour of the trailing edge of the wing,
2. The axial flow fan according to claim 1, wherein the fan is formed from one curve or two curves having different curvatures are formed continuously. 3. A line connecting an intersection point Q between a fan rotation center point O, a contour α of a blade trailing edge, and a contour β of an outer peripheral portion of the blade with reference to a plane perpendicular to the fan rotation axis. OQ, a line connecting the intersection S of the fan rotation center point O, the contour line γ of the blade leading edge, and the contour line β of the blade outer peripheral portion is OS, and the angle formed by the OQ and OS is θt; Assuming that segments PG1 and PG2 are respectively connected from the arc-shaped center point P of the profile of the trailing edge of the blade to two end points G1 and G2 of the arc, the line segment PG1 and the line segment PG2 are formed. The axial flow fan according to claim 1, wherein the angle? K is set to be 0.7 to 0.8 times the angle? T. 4. The inverted arc forming the contour of the trailing edge of the wing,
The angle θt formed by the OQ and the OS is defined by two curved curves having different curvatures, where each inverted arc-shaped center point is T, U, and each inverted arc-shaped end point is J1, J2, J3. A line segment TJ1 connecting the center point T and the end point J1, an angle θm formed by a line segment TJ2 connecting the center point T and the end point J2, a line segment UJ2 connecting the center point U and the end point J2, and a center point. The angle is set to be 1.3 to 1.5 times as large as an angle (θm + θn) obtained by adding an angle θn formed by a line segment UJ3 connecting U and the end point J3. The axial fan according to claim 2. 5. An axial flow fan comprising a plurality of blades, which are provided along a peripheral surface of a cylindrical boss hub, and blowing in an axial direction with the rotation of the blades. A wing trailing edge portion, a wing leading edge portion in the air introduction direction, and a wing outer peripheral portion forming an outer periphery. The contour of the wing trailing edge portion is an introduction direction opposite to the air outflow direction. An axial flow fan characterized in that it is formed in a substantially V-shaped concave shape. 6. An axial flow fan which comprises a plurality of blades as blades along a peripheral surface of a cylindrical boss hub, and blows in an axial direction with the rotation of the blades. A wing trailing edge portion, a wing leading edge portion in the air introduction direction, and a wing outer peripheral portion forming an outer periphery. The contour of the wing trailing edge portion is an introduction direction opposite to the air outflow direction. An axial flow fan characterized in that it is formed in a substantially trapezoidal concave shape that is depressed into a groove. 7. An intersection point between the contour line α of the trailing edge of the blade and the contour line β of the blade outer peripheral portion is defined as Q, and an intersection point of the contour line γ of the blade leading edge portion and the contour line β of the blade outer peripheral portion is defined as Q. S, and a plane perpendicular to the fan rotation axis Y passing through the intersection Q is denoted by QY, and a plane passing through the intersection S and perpendicular to the fan rotation axis Y is denoted by SY. A vertical line extending between the plane QY and the plane SY For Hf,
The vertical maximum distance Hk between the plane QY and the contour line α of the trailing edge of the wing is set so as to be in the range of 10 to 20%. Axial fan. 8. The contour line of the trailing edge of the wing includes the concave portion,
Shoulders formed at two locations on the inner circumferential side and the outer circumferential side of the fan are continuously provided, and the length of the inner circumferential side shoulder is L1 and the length of the outer circumferential side shoulder is L2. The axial fan according to any one of claims 1 to 7, wherein the axial flow fan is set so as to satisfy? L2.