JP6531457B2 - Propeller fan - Google Patents

Description

  The present invention relates to a propeller fan.

Conventionally, a notch is provided at the blade trailing edge of a propeller fan (see, for example, Patent Literature 1 and Patent Literature 2).
In the propeller fan described in Patent Document 1, it is noted that a notch is provided at the trailing edge of the blade, noting that noise is generated due to separation of the vortices generated near the blade tip on the negative pressure side from the blade surface. It is
More specifically, since the vortices generated in the vicinity of the blade tip are captured and held along the blade surface by the notches, the fluctuation and development of the vortices are suppressed and the generation of noise is suppressed.

Further, in the propeller fan described in Patent Document 2, a notch is provided at the trailing edge of the blade, noting that the air volume is reduced because air leaks from the high pressure side to the negative pressure side when the fan rotates. It is something like that.
That is, on the blade positive pressure surface, air flows from the axial direction to the blade outer peripheral edge in the centrifugal direction by the action of the centrifugal force, and leakage occurs from the outer peripheral edge to the negative pressure side. By reducing the pressure rise and causing the air flowing from the leading edge to the trailing edge of the wing to be restricted and flow in the circumferential direction as it is, air leakage is reduced and the air volume is increased. Therefore, the propeller fan provided with the notch can exhibit the same air volume with lower input power as compared with the propeller fan without the conventional notch.

JP, 2014-80970, A JP 2003-206894 A

However, when a conventional propeller fan provided with a notch at the trailing edge of the blade was examined, in the conventional propeller fan, a sufficient reduction in power (reduction of power consumption) was obtained by the notch at the trailing edge of the blade. I found it was not.
That is, if the notch area is small, the effect of low input can not be obtained sufficiently, and if the notch area is too large, the air volume reduction will be large, so it is necessary to compensate for the air volume reduction by increasing the rotational speed, There is a problem that the input becomes high.

  The present invention has been made to solve the conventional problems, and it is an object of the present invention to provide a propeller fan capable of suppressing the generation of noise and achieving low input.

(1) One aspect according to the present invention is
A rotating shaft that rotates around the rotation center,
A plurality of blades are provided in the circumferential direction of the rotary shaft, and are formed outward from the rotary shaft;
And a notch formed from a rear edge located opposite to the side in the rotational direction of the wing toward the front edge located on the side of the rotational direction,
The notch portion is formed between a point E on the rear edge portion closer to the rotary shaft portion and a point A farther from the rotary shaft portion than the point E,
Assuming that the point closest to the rotary shaft side at the tip of the front edge side of the notch is the point C,
Said wing, said distance from the rotation center to the point E Rin0 short distance Rin 1 by remote from the rotational center to the point C, the cutout portion than the straight line connecting the a point C said point E A propeller fan is provided, which has a convex portion that extends and whose distance Rin2 from the rotation center to a point D of the convex portion farthest away exceeds the distance Rin1.

(2) In the propeller fan described in (1) above,
The distance from the center of rotation of the rotary shaft portion to the point of the blade furthest outward is R0,
The distance Rin1 is not less than 0.6 times and not more than 0.8 times R0,
The propeller fan may be a propeller fan in which a distance Rin2 from the rotation center to a point D of the convex portion farthest outside is more than 1.0 times and not more than 1.2 times the distance Rin1.

(3) Furthermore, in the propeller fan described in (2),
The tip is defined by the point C and the point B,
The tip portion is either a shape in which the point B overlaps and converges to the point C or a shape having a width having two points of the point C and the point B outside the point C,
The distance Rin3 from the rotation center to the point B is 0.6 times or more and 0.8 times or less of the R0,
A distance Rin4 from the rotation center to the point A is shorter than the R0 and longer than the distance Rin3;
The point D is positioned within a range of 5 ° to 25 ° on the rear edge side at an angle of the rotation direction based on a line connecting the point C and the rotation center,
The point A may be a propeller fan located between a straight line LD passing through the rotation center and the point D and a straight line LE passing through the rotation center and the point E.

  According to the present invention, a propeller fan capable of achieving low input can be provided.

It is the front view which looked at the propeller fan of the embodiment of the present invention from the pressure side. It is the rear view which looked at the propeller fan of the embodiment of the present invention from the suction side. It is sectional drawing of the propeller fan cut | disconnected along the rotating shaft part. It is explanatory drawing which shows the shape and dimension of the notch part and convex part which were provided in the wing | blade. It is sectional drawing which shows the flow of the air which flows through the surface and notch part of a wing | blade. (A) is a front view of the wing | blade of a comparative example, (B) is a front view of the wing | wing of an Example. It is a graph which shows the measurement result with respect to an Example and a comparative example, (A) is a graph which shows the relationship between air volume and electric power (input power), (B) is a graph which shows the relationship between air volume and static pressure. , (C) is a graph showing the relationship between the air volume and the rotational speed. It is the front view seen from the positive pressure side which shows the modification of the propeller fan of embodiment of this invention. It is a figure corresponding to Drawing 4 in a modification of a propeller fan of an embodiment of the present invention.

Hereinafter, a propeller fan according to an embodiment of the present invention will be described using the drawings.
As shown in FIGS. 1 and 2, a propeller fan 10 according to an embodiment of the present invention includes a rotating shaft portion 20 attached to a rotating shaft (not shown) of a fan motor, and the rotating shaft portion 20 is doubled. It is formed in a cylindrical shape having a cylindrical portion, and has a boss 24 for attaching a rotation axis at the center of the inner cylindrical portion 21.
Further, the outer cylindrical portion 22 of the rotary shaft portion 20 is firmly connected to the outer side of the inner cylindrical portion 21 via a rib.

A plurality of (for example, three) wings 30 formed outward are provided on the outer side of the outer cylindrical portion 22 along the circumferential direction of the rotary shaft portion 20.
The wing 30 is a plate-like member, and the outer peripheral edge portion 32 is wider than the base end portion 31 which is the connection side with the rotary shaft portion 20.
The front edge 33, which is the front side in the rotational direction of the wing 30 (hereinafter also referred to as “front side”), is the rear edge 34 side located on the opposite side of the rotation direction (hereinafter also referred to as “rear side”) For example, an arc-shaped notch 35 is provided which is curved toward the end.

As shown in FIG. 3, the base end portion 31 of the wing 30 is coupled to the outer cylinder portion 22 along the circumferential direction of the outer peripheral surface of the outer cylinder portion 22 of the rotary shaft portion 20.
The wing 30 is formed so that the surface 301 of the wing 30 is gently curved from the negative pressure side to the positive pressure side from the front edge 33 to the rear edge 34 in the circumferential direction of the rotary shaft 20 There is.
Thus, when the propeller fan 10 rotates, the air is cut by the front edge 33 at the notch 35 of the wing 30 and flows along the surface 301 of the wing 30 to flow to the positive pressure side.

As shown in FIGS. 1 and 4, the trailing edge 34 of the wing 30 is provided with a notch 40 towards the leading edge 33.
The notch 40 is formed in a substantially V-shape that opens rearward from the rear edge 34 and tapers toward the front edge 33.

  As shown in FIG. 4, the notch 40 is formed between a point E on the rear edge 34 of the wing 30 on the side of the rotary shaft 20 and a point A farther from the rotary shaft than the point E, Assuming that the point closest to the rotary shaft portion 20 in the tip 42 on the front edge 33 side of the notch 40 is a point C, the wing 30 has a notch that is a notch from a straight line LCE connecting the point E and the point C A projecting portion 41 (see hatching in FIG. 1) extending to the 40 side is provided.

FIG. 5 is a cross-sectional view of propeller fan 10 cut along a straight line connecting X and X ′ in FIG. 4, in which wing surface 40 and notch portion 40 in a wing provided with convex portion 41 in notch portion 40 are shown. It shows the flow of flowing air.
FIG. 5 particularly shows the flow of centrifugal air flowing on the surface 301 of the wing 30.

Air flows circumferentially from the front edge 33 to the rear edge 34 of the wing 30 on the surface 301 of the wing 30, but as the rotational speed of the propeller fan 10 increases, air in the centrifugal direction as shown in FIG. Flow of As shown in FIG. 5, a part of the air W2 of the centrifugal air W1 flowing on the surface 301 of the wing 30 flows to the negative pressure side through the notch 40. As in the present embodiment, the convex portion 41 is provided so as to extend from the surface 301 of the wing to the notch 40 side. Further, when the flat surface 411 of the convex portion 41 is inclined toward the negative pressure surface with respect to the surface 301 of the wing 30, a part of the air W2 in the centrifugal air W1 flows along the flat surface 411 to the negative pressure surface However, in the present embodiment, since the flat surface 411 of the convex portion 41 extends along the surface 301 of the wing, the amount of air W2 flowing from the notch 40 to the negative pressure side is suppressed.
As described above, the centrifugal component of the wind flowing from the notch 40 to the negative pressure side can be suppressed, and the centrifugal component of the wind can be effectively used. Thus, the air volume of the propeller fan can be improved, which results in low Input can be realized.

  Next, to obtain the shape of the notch 40 provided with such a convex portion 41, the preferred range of each of the points A, B, C, D, E, and F (the rotation center of the rotation shaft 20) The distance from the point 23 and the circumferential position about the rotary shaft 20 will be described in detail with reference to FIG.

First, in the wing 30, with the distance R0 from the center of rotation 23 of the rotary shaft portion 20 to the point furthest outward as a reference for the distance from the center of rotation 23 at each point, points A, B, C, D, and A range in which the distance from the rotation center 23 of E is a suitable distance is shown below.
In addition, since the point F is located on the outer periphery of the wing 30, which is equal to the distance R0 from the rotation center 23 of the rotation shaft portion 20 to the outermost point in the wing 30, the distance from the rotation center 23 is R0 is there.
The distance Rin1 of the point C from the rotation center 23 is preferably selected in the range of 0.6 times to 0.8 times the R0, and the distance Rin0 of the point E from the rotation center 23 is greater than Rin1. It is preferable to be shortened.

Further, the point D is the most distant point from the rotation center 23 in the convex portion 41, and the distance Rin2 from the rotation center 23 of the point D is 1.0 times or more and 1.2 times the distance Rin1. It is preferable to select in the following range.
Since the points C, E, D are distances selected from the above range, the distance Rin2 from the rotation center 23 to the point D is not less than the distance Rin1 from the rotation center 23 to the point C, and Since it becomes longer than the distance Rin0 from the center 23 to the point E, it is possible to form the convex portion 41 which surely protrudes to the notch 40 side.

Next, the point B is preferably selected such that the distance Rin3 from the rotation center 23 is in the range of not less than 0.6 times and not more than 0.8 times R0.
In the present embodiment, the point B is provided on the extension of the line LC connecting the rotation center 23 and the point C, but the point B is an extension of the line LC connecting the rotation center 23 and the point C It is not essential to be located on the line.
However, since the position on the straight line that extends the line LC connecting the rotation center 23 and the point C is one of the preferable positions of the point B in the circumferential direction around the rotation shaft portion 20, such a point By defining B, the circumferential position of point B can be easily determined.

  The tip end portion 42 of the notch 40 is defined by points B and C, and in the present embodiment, has a width having two points of the point C and the point B outside the point C as shown in FIG. The tip portion 42 may have a shape such that the distance Rin3 from the rotation center 23 to the point B is equal to Rin1 so that the point B overlaps the point C and converges.

  In addition, although it is preferable that the point Rin is selected within a range in which the distance Rin4 from the rotation center 23 is shorter than R0 and longer than the distance Rin3, the point Rin is the same as R0. If A is positioned on the outer peripheral edge 32 (uppermost periphery) of the wing 30, for example, as indicated by a point A 'in FIG. good.

Next, the circumferential position around the rotation shaft portion 20 will be described.
The circumferential positions of the point C and the point B around the rotary shaft 20 may be determined according to the depth of cut required for the notch 40.
That is, the notch 40 may be set to have a cut depth that can achieve the same effect as that of the conventionally provided notch.
As described above, in the case where the point B is positioned on a straight line extending the line LC connecting the rotation center 23 and the point C, the point C is determined so that the necessary cutting depth can be obtained in the notch 40 Just good.

The point F is, as described above, a point on the outer periphery of the wing 30 and also a point on the trailing edge 34 of the wing 30.
Therefore, in other words, the point F is the outermost point of the trailing edge 34 located on the outermost periphery (on the outer peripheral edge 32) of the wing 30, and this point F corresponds to the point C and the rotation center 23 It is preferable to be disposed within a range of 15 ° on the front end side to 15 ° on the rear end side at an angle in the rotational direction with reference to the connecting line LC.

The point D is preferably disposed within a range of 5 ° to 25 ° on the rear edge side at an angle in the rotational direction with reference to a line LC connecting the point C and the rotational center 23.
Furthermore, it is sufficient that at least point A of the point A be disposed on the rear edge side of the line LC connecting the point C and the rotation center 23, a straight line LD passing through the rotation center 23 and the point D; Preferably, it is disposed between the point 23 and a straight line LE passing through the point E.

  By providing the points A and B within the range as described above, the outer side of the notch 40 suitable for the edge on the rotary shaft 20 side of the notch 40 defined by the points E, D and C is provided. The edge can be defined, and by providing the point F within the range as described above, the shape of a suitable wing 30 to be provided on the outside adjacent to the notch 40 can be defined. .

Next, measurement results of a specific example in which the convex portion 41 is provided in the notch 40 and a comparative example in which the convex portion 41 is not provided will be described.
FIG. 6A shows the blade shape of a propeller fan of a comparative example, and FIG. 6B shows the blade shape of a propeller fan of an embodiment.

In the wing 30 of the embodiment, the reference length R0 is 220 mm and the point B is at a position slightly distant from the rotation center 23 than the point C, and the distance from the rotation center 23 for each of the points A, C and D In the above-described preferred range, the convex portion 41 is formed so as to protrude into the notch 40 as a substantially central distance.
Moreover, the comparative example has the same shape and dimensions as those of the example except that the convex portion 41 is not provided.

FIG. 7 is a graph showing measurement results for the example and the comparative example.
7 (A), (B), and (C) show an example by a solid line, and a broken line shows a comparative example.
FIG. 7 (A) is a graph showing the relationship between air volume and power (input power), FIG. 7 (B) is a graph showing the relationship between air volume and static pressure, and FIG. It is a graph which shows a relation with number of rotations of a minute.
In FIGS. 7A, 7B, and 7C, the scale of the air volume on the horizontal axis is the same.

As shown in FIG. 7A, it can be seen that the air flow can be generated in the example with the same input power than in the comparative example.
In particular, it can be seen that the air flow can be taken out in the example as well as in the comparative example at the point of intersection with the resistance curve shown in FIG. 7 (B).
Similarly, looking at the time of use air volume in FIG. 7C, it can be seen that the air volume is obtained with a small number of rotations in the example, and from this also it is confirmed that low input can be realized It can.

  As described above, the propeller fan 10 according to the present embodiment is provided in the circumferential direction of the rotary shaft portion 20 rotating around the rotation center 23 and in the circumferential direction of the rotary shaft portion 20 and formed outward from the rotary shaft portion 20 Although the notch 30 is provided in the wing 30 from the rear edge 34 toward the front edge 33, the projection 30 has a convex shape that protrudes to the notch 40 in the notch 40. Since the centrifugal component of the wind flowing from the notch 40 to the negative pressure side is suppressed and the centrifugal component of the wind is effectively used by providing 41, the input can be reduced (power consumption can be reduced).

As mentioned above, although the propeller fan of the present invention has been described based on the specific embodiment, the present invention is not limited to the above specific embodiment, and a range which does not deviate from the technical concept of the present invention It goes without saying that various modifications and improvements may be made.
For example, in the above embodiment, the points A, B, C, D, E, and F have angular shapes, but the points of these points are rounded in FIGS. 8 and 9. It may be shaped as shown, in which case each point is defined as the vertex of the rounded portion (the point that is the most out) as shown in FIG.
As described above, various modifications and improvements without departing from the technical concept are also included in the technical scope of the present invention, which will be apparent to those skilled in the art from the description of the claims. It is.

DESCRIPTION OF SYMBOLS 10 propeller fan 20 rotation shaft part 23 rotation center 30 wing | wing 32 outer periphery part 33 front edge part 34 rear edge part 40 notch part 41 convex shape part 42 tip part LCE straight line

Claims (3)

A rotating shaft that rotates around the rotation center,
A plurality of blades are provided in the circumferential direction of the rotary shaft, and are formed outward from the rotary shaft;
And a notch formed from a rear edge located opposite to the side in the rotational direction of the wing toward the front edge located on the side of the rotational direction,
The notch portion is formed between a point E on the rear edge portion closer to the rotary shaft portion and a point A farther from the rotary shaft portion than the point E,
Assuming that the point closest to the rotary shaft side at the tip of the front edge side of the notch is the point C,
Said wing, said distance from the rotation center to the point E Rin0 short distance Rin 1 by remote from the rotational center to the point C, the cutout portion than the straight line connecting the a point C said point E A propeller fan having a convex portion that extends and a distance Rin2 from the rotation center to a point D of the convex portion farthest away exceeds the distance Rin1. The distance from the center of rotation of the rotary shaft portion to the point of the blade furthest outward is R0,
The distance Rin1 is not less than 0.6 times and not more than 0.8 times R0,
The distance Rin2 from the center of rotation to the point D of the convex portion farthest outside is more than 1.0 times and not more than 1.2 times the distance Rin1. Propeller fan described in. The tip is defined by the point C and the point B,
The tip portion is either a shape in which the point B overlaps and converges to the point C or a shape having a width having two points of the point C and the point B outside the point C,
The distance Rin3 from the rotation center to the point B is 0.6 times or more and 0.8 times or less of the R0,
A distance Rin4 from the rotation center to the point A is shorter than the R0 and longer than the distance Rin3;
The point D is positioned within a range of 5 ° to 25 ° on the rear edge side at an angle of the rotation direction based on a line connecting the point C and the rotation center,
The propeller fan according to claim 2, wherein the point A is located between a straight line LD passing through the rotation center and the point D, and a straight line LE passing through the rotation center and the point E.

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