JP2003065295A - Axial flow blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an axial flow blower which can keep load of a generator low even if a blowing amount is increased by raising the number of rotation. SOLUTION: In this axial flow blower with a plurality of blades 12 integrally formed around a hub 11, at a corner part where a blade rear edge part 21 which is an air outflow part during rotation crosses a blade outer circumference part 22, an expanded part 23 expanding in the protruding state in the air outflow direction is formed, and the expansion part is formed within the range of 0.6R to R where a radius from the center of a rotation shaft to the outermost circumference of the blade is R.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an axial blower used for an outdoor unit of an air conditioner.

[0002]

2. Description of the Related Art As an axial blower of this type, one having a structure shown in FIGS. 13 and 14 is known. Among these, in the axial blower 10A shown in FIG. 13, the hub 11 and the plurality of blades 12 (only one is shown here) are integrally formed. This axial blower 1
Since 0A rotates in the direction of the arrow X, the blade trailing edge portion 21 that is in contact with the air outflow portion of the blade 12 is formed in a substantially linear shape. Therefore, when increasing the air volume, the load of the electric motor that drives the blower becomes large. There was also a problem that the blowing noise increased.

On the other hand, the blade trailing edge portion 21 of the axial blower 10B shown in FIG. 14 is curved in a substantially arc shape, and the blade trailing edge portion 21 is formed.
The corner portion where the blade and the blade outer peripheral portion 22 intersect is a bulging portion 23 that bulges in a convex shape. However, the range forming the bulging portion 23 exists in a wide region exceeding 0.5r, where r is the radius from the center O of the rotating shaft to the blade outer peripheral portion 22,
When the rotational speed of the blower is increased to increase the air volume in the same manner as described above, the flow loss at the blade trailing edge portion 21 increases, the load on the blower drive motor increases, and the blower noise increases. There was a problem of doing.

The present invention has been made to solve the above problems, and its purpose is to reduce the load on the electric motor even when the number of rotations is increased to increase the amount of blown air. To provide a blower.

Another object of the present invention is to provide an axial blower capable of suppressing vortices generated at the trailing edge of the blade and suppressing an increase in blast noise.

Another object of the present invention is to provide an axial-flow blower excellent in moldability and cost reduction.

[0007]

The invention according to claim 1 is
In an axial-flow blower in which a plurality of blades are integrally formed around the hub, the corner where the trailing edge of the blade, which is the rotating air outlet, and the outer periphery of the blade intersect is expanded in a convex shape in the air outlet direction. The bulging portion is formed in the range of 0.6R to R, where R is the radius from the center of the rotating shaft to the outermost periphery of the blade.

According to a second aspect of the present invention, in the axial blower according to the first aspect, the bulging portion has a contour in which three or more different arcs are connected.

According to a third aspect of the present invention, in the axial blower according to the first or second aspect, the blade trailing edge portion extending from the bulging portion in the rotation axis direction is curved in a wind inflow direction, and after being curved. The edge is made up of two or more arcs.

According to a fourth aspect of the present invention, in the axial blower according to the third aspect, when the arc length of the outer peripheral edge of one blade is CL, the arc length of the curved portion at the trailing edge of the blade is 0. 4-0.6C
It is characterized in that the range is L.

According to a fifth aspect of the present invention, in the axial blower according to the third aspect, the center of the rotary shaft is O, and the center is derived from this center O to contact the inner part (Q) of the bay at the trailing edge of the blade. Km, a line segment that is derived from the center O and comes into contact with the tip (T) of the bulge portion is Kn, and a line segment that is derived from the center O and that corresponds to the rotating air inflow portion is the outer peripheral end of the blade leading edge ( Sf) is a line segment that comes into contact with Kf, and the central angle between the line segment Km and the line segment Kn is α1,
When the central angle between the line segment Kn and the line segment Kf is α2,
It is characterized in that α1 = 0.05 × α2 to 0.15 × α2.

According to a sixth aspect of the invention, in the axial blower according to the third aspect, the starting point of the curved portion on the radially inner side of the blade trailing edge portion is U, and the blade is derived from the center O of the rotary shaft and is located behind the blade. The line segment that contacts the inner part of the bay (Q) at the edge is Km, the leg length of the perpendicular line drawn from the point U to the line segment Km is L1, and the line segment Km from the tip of the bulge (T). The length of the leg of the perpendicular line
When set to 2, it is characterized in that L2 = 0.5 × L1 to 0.7 × L1.

According to a seventh aspect of the present invention, in the axial blower according to the first aspect, the radius from the center of rotation to the outer circumference of the blade is R, the arc length of the outer circumference is CL, and the radius from the center of rotation is 0. Among the arcs having a radius of 6 × R, Ye = 0.4CL to 0.6C, where Ye is the arc length from the blade leading edge portion that hits the air inflow portion to the blade trailing edge portion that hits the air outflow portion.
It is characterized in that it is L.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will now be described in detail based on the preferred embodiments shown in the drawings. FIG. 1 is a plan view showing the overall configuration of an axial blower according to the present invention as viewed in the axial direction. This axial blower 1 has a hub 11 and three blades 1.
2 and 1 are integrally formed and rotate in the direction of arrow X. 2 shows one blade 12 of the axial blower 1 shown in FIG.
Is an enlarged view of the wing 12 rotating in the direction of the arrow X.
The bulging portion 23 is formed by bulging a portion of the blade trailing edge portion 21 corresponding to the air outflow portion and the blade outer peripheral portion 22 in a convex shape in the air flowing direction. In this case, when the radius of the bulging portion 23 from the center O of the rotating shaft to the blade outer peripheral portion 22 is R, the bulging portion 23 is 0.6R to R of the blade trailing edge portion 21.
Is formed in the range.

FIG. 3 is a diagram showing the relationship between the range of formation of the bulging portion 23 and the amount of air blow and the input of the electric motor.
Is formed in the range from 0.6R to R in the blade trailing edge portion 21, flow loss near the blade trailing edge portion 21 can be suppressed, and the load applied to the electric motor can be reduced. Therefore, the load applied to the electric motor can be reduced while increasing the peripheral speed of the blade outer peripheral portion 22 to increase the blown air amount, so that the energy saving performance of the air conditioner or the like can be improved.

FIG. 4 is for explaining the contour shapes of the blade trailing edge portion 21 and the bulging portion 23 shown in FIG. 2. First, the bulging portion 23 is connected to the blade outer peripheral portion 22 and is radially outward. An arc 31 with a relatively large radius of curvature that enters the inside, an arc 32 with a smallest radius of curvature that is convex in the air outflow direction, and an arc 33 that has a radius of curvature larger than this arc 32 and is concave in the air outflow direction. It has a shape in which and are sequentially connected. Further, the blade trailing edge portion 21 on the radially inner side of the bulging portion 23 has a relatively large radius of curvature, and the arc 34 that is concave in the air outflow direction and the air outflow with the radius of curvature smaller than this arc 34. It has a shape in which a circular arc 35 having a concave shape in the direction is sequentially connected.

As described above, by forming the bulging portion 23 into a shape in which three or more different arcs are connected, it is possible to suppress the generation of vortices and reduce noise. Further, by making the portion on the radially inner side of the bulging portion 23 into a shape in which two circular arcs are connected, the blade area can be increased as compared with the case where it is formed by one circular arc, and the air flow rate is increased. be able to.

FIG. 5 shows the relationship between the arc length CL of the blade outer peripheral portion 22 of the blade 12 and the arc length LW of the curved portion of the blade trailing edge portion 21. The arc length of the curved portion of the blade trailing edge portion 21 is shown in FIG. LW 0.4
The range is set to CL to 0.6 CL.

FIG. 6 is a diagram showing the relationship between the ratio of the curved portion LW to the arc length CL, the air flow rate, and the motor input.
By setting the arc length LW of the curved portion in the range of 40% to 60% with respect to the arc length CL, it is possible to suppress the load given to the electric motor while securing a constant amount of air flow.

FIG. 7 is a view for explaining the ratio of the bulging portion 23 occupied in the circumferential direction of the blade 12, where the center of the rotation axis is O,
A line segment that is derived from this center O and comes into contact with the inner part Q of the blade trailing edge portion 21 is Km, and a line segment that is derived from this center O and is in contact with the tip portion T of the bulging part 23 is from Kn and from the center O. Let Kf be the line segment that comes out and contacts the outer peripheral edge S of the blade leading edge that hits the rotating air inflow portion, and let the central angle between the line segment Km and the line segment Kn be α.
1, when the central angle between the line segment Kn and the line segment Kf is α2, α1 = 0.05 × α2 to 0.15 × α2 is shown.

FIG. 8 is a diagram showing the relationship between α1 / α2 and the amount of blown air and the input of the electric motor. When the number of revolutions of the blower is increased and the amount of blown air is increased, the blowing noise is increased. Therefore, the load applied to the electric motor can be reduced.

FIG. 9 shows the radially outer portion of the curved portion of the blade trailing edge portion 21 and the radially inner portion thereof protruding in the air outflow direction. The radially inner portion of the blade trailing edge portion 21 is curved. The starting point of the section is U, the line segment that is derived from the center O of the rotating shaft and comes into contact with the inner part Q of the blade trailing edge portion 21 is Km, and the line segment Km from the point U
Let L1 be the length of the leg of the perpendicular drawn down to L2, and let L2 be the length of the leg of the perpendicular drawn from the tip T of the bulging portion 23 to the line segment Km. It is set to 7 × L1.

According to this configuration, as is apparent from the relationship between the ratio of L2 to L1 shown in FIG. 10, the air flow rate, and the motor input, the load applied to the electric motor can be suppressed to a low level without reducing the air flow rate. You can

FIG. 11 shows the relationship between the arc length of the blade outer peripheral portion 22 of the blade 12 and the circumferential arc length of the portion of the blade trailing edge portion 21 corresponding to the inner part of the bay. R is the radius to the outer periphery of the blade, and CL is the arc length of the outer periphery, and among the arcs having a radius of 0.6 × R from the center of rotation, the blade trailing edge that contacts the air inflow portion to the air outflow portion Ye = 0.4CL to 0.6C when the arc length to the part is Ye
It is set to L.

FIG. 12 is a diagram showing the relationship between the ratio of the arc length Ye from the blade leading edge to the blade trailing edge with respect to the arc length CL of the outer circumference, the noise value, and the motor input, which is clear from this diagram. As described above, the load on the electric motor can be reduced without increasing the blowing noise.

[0026]

As is apparent from the above description, according to the present invention, there is provided an axial blower capable of suppressing the load on the electric motor even when the rotation speed is increased to increase the blown air volume. To be

[Brief description of drawings]

FIG. 1 is a plan view showing the overall configuration of an axial blower according to the present invention as viewed in the axial direction.

FIG. 2 is an enlarged view showing one blade of the axial blower 1 shown in FIG.

FIG. 3 is a diagram showing a relationship between a formation range of a bulge portion, an air flow rate and an input of an electric motor.

FIG. 4 is a diagram for explaining contour shapes of a blade trailing edge portion and a bulging portion shown in FIG. 2;

FIG. 5 is a plan view showing the relationship between the arc length of the blade outer peripheral portion and the arc length of the blade trailing edge portion 2 curved portion.

FIG. 6 is a diagram showing the relationship between the arc length, the air flow rate, and the motor input.

FIG. 7 is a diagram for explaining the ratio of the bulging portion occupied in the circumferential direction of the blade.

FIG. 8 is a diagram showing the relationship between the ratio of the bulging portion occupied in the circumferential direction of the blade, the air flow rate, and the motor input.

FIG. 9 is a view showing a radially outer side portion and a radially inner side portion of a curved portion of a blade trailing edge portion in a protruding state in a wind outflow direction.

10 is a diagram showing the relationship between the ratio of the radially outer portion shown in FIG. 9 to the protruding portion in the air outflow direction, the air flow rate, and the motor input.

FIG. 11 is a diagram showing the relationship between the arc length of the blade outer peripheral portion and the arc length in the circumferential direction of the portion of the blade trailing edge portion corresponding to the inner part of the bay.

FIG. 12 is a diagram showing a relationship between the ratio of the arc length from the blade leading edge portion to the blade trailing edge portion to the arc length of the outer circumference, the noise value, and the motor input.

FIG. 13 is a plan view seen from the axial direction to show the configuration of a conventional axial-flow blower.

FIG. 14 is a view showing another configuration of the conventional axial blower,
The top view seen from the axial direction.

[Explanation of symbols]

1 axial blower 11 hubs 12 wings 21 Wing trailing edge 22 Wing periphery 23 bulge 31-34 arc

Claims (7)

[Claims] 1. An axial flow blower in which a plurality of blades are integrally formed around a hub, wherein a corner portion where a trailing edge portion of the blade, which corresponds to an air outlet portion during rotation, intersects with an outer peripheral portion of the blade, is formed in an air outlet direction. In addition to forming a bulging portion that bulges in a convex shape at the same time, and assuming that the radius from the center of the rotating shaft to the outermost periphery of the blade is R, the bulging portion is formed in the range of 0.6R to R. A characteristic axial-flow blower. 2. The axial blower according to claim 1, wherein the bulging portion has a contour in which three or more different arcs are connected. 3. The blade trailing edge portion extending from the bulging portion in the rotation axis direction is curved in the direction in which wind flows, and the curved trailing edge portion is formed by connecting two or more arcs. Axial blower described in. 4. When the arc length of the outer peripheral edge of one blade is CL, the arc length of the curved portion at the trailing edge of the blade is 0.4 to 0.6 CL.
The axial flow blower according to claim 3, wherein 5. A line segment that is derived from the center O and contacts the inner part of the blade (Q) at the trailing edge of the blade is K.
m, a line segment that is derived from the center O and comes into contact with the tip end portion (T) of the bulge portion is Kn, and an outer peripheral end (S) of the blade leading edge portion that is derived from the center O and abuts the rotating air inflow portion. The contacting line segment is Kf, and the central angle between the line segment Km and the line segment Kn is α1,
When the central angle between the line segment Kn and the line segment Kf is α2,
The axial blower according to claim 3, wherein α1 = 0.05 × α2 to 0.15 × α2. 6. A line segment that is derived from the center O of the rotating shaft and is in contact with the deep part (Q) of the trailing edge of the blade, where U is the starting point of the curved portion on the radially inner side of the trailing edge of the blade. Km, the length of the leg of the perpendicular drawn from the point U to the line Km is L1, and the length of the leg of the perpendicular drawn from the tip (T) of the bulge to the line Km is L2. , L2 = 0.5 × L1 to 0.7 × L1
The axial-flow blower according to claim 3, wherein 7. The radius from the center of rotation to the outer circumference of the blade is R, the arc length of the outer circumference is CL, and the arc length from the center of rotation is 0.6.
Among the arcs having a radius of × R, when Ye is the arc length from the blade leading edge portion that hits the air inflow portion to the blade trailing edge portion that hits the air outflow portion, Ye = 0.4CL to 0.6CL. The axial blower according to claim 1, which is characterized in that.