fan

Abstract

To provide a fan capable of improving air-blowing efficiency.SOLUTION: A fan according to an embodiment includes a blade and a bell mouth. The blade rotates around a rotation axis along a first direction. The bell mouth includes a staircase structure positioned around the blade along a first surface perpendicular to the first direction. The staircase structure is formed in such a manner that an opening surrounded by the staircase structure is widened toward an air-blow direction by the blade.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD An embodiment of the present invention relates to a fan. [Background technology]

[0002] There are fans that blow air, and there is a demand for technology that can improve the airflow efficiency of these fans. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-173210 Summary of the Invention [Problem to be solved by the invention]

[0004] The problem to be solved by the present invention is to provide a fan that can improve air blowing efficiency. [Means for solving the problem]

[0005] A fan according to an embodiment includes blades and a bell mouth. The blades rotate about a rotation axis along a first direction. The bell mouth includes a staircase structure positioned around the blades along a first plane perpendicular to the first direction. The staircase structure is formed so that an opening surrounded by the staircase structure widens in the direction of air blown by the blades. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view showing a fan according to an embodiment. [Figure 2] FIG. 2 is a side view showing the fan according to the embodiment. [Figure 3] FIG. 3 is a side view showing a part of the fan according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing a part of a fan according to a reference example. [Figure 5] 5(a) and 5(b) are schematic diagrams showing a part of the fan according to the embodiment. [Figure 6] FIG. 6 shows simulation results showing the characteristics of the fans according to the reference example and the embodiment. [Figure 7] FIG. 7 is a schematic diagram showing the manufacturing process of a bell mouth. [Figure 8] FIG. 8 is a schematic diagram showing a fan according to a first modified example of the embodiment. [Figure 9] FIG. 9 is a schematic diagram showing the characteristics of a fan according to a first modified example of the embodiment. [Figure 10] FIG. 10 is a schematic diagram showing a fan according to a second modified example of the embodiment. [Figure 11] FIG. 11 is a schematic diagram showing a fan according to a third modified example of the embodiment. [Figure 12] FIG. 12 is a schematic diagram showing a fan according to a fourth modified example of the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily the same as those in reality. Even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In the present specification and the drawings, elements similar to those already explained are given the same reference numerals and detailed explanations will be omitted as appropriate.

[0008] FIG. 1 is a perspective view showing a fan according to an embodiment. As shown in Fig. 1, a fan 1 according to this embodiment includes blades 10 and a bell mouth 20. For the sake of explanation, an X direction, a Y direction, and a Z direction (first direction) are used here. The X direction, the Y direction, and the Z direction are perpendicular to each other.

[0009] The blades 10 rotate about a rotation axis R along the Z direction. The blades 10 include a plurality of plates 11 inclined with respect to an XY plane (first plane) perpendicular to the Z direction. In the illustrated example, three plates 11 are provided. The number of plates 11 can be changed as appropriate. As the blades 10 rotate, air moves in the air blowing direction D1.

[0010] The bell mouth 20 includes a base portion 21 and an annular portion 22. The base portion 21 is plate-shaped and extends along the XY plane. When viewed from the Z direction, the annular portion 22 is circular and has its center on the rotation axis R. The blade 10 is provided inside the annular portion 22.

[0011] The fan 1 according to the embodiment is used in, for example, an outdoor unit, a ventilation fan, and the like.

[0012] Fig. 2 is a side view showing the fan according to the embodiment. Note that Fig. 2 shows the cross-sectional structure of the bell mouth. Also, Fig. 1 omits the drive unit 12 shown in Fig. 2.

[0013] 2, a driving unit 12 is connected to the blade 10. The driving unit 12 is, for example, a motor. A rotation axis R of the driving unit 12 is connected to the center of the blade 10 in the XY plane. The driving unit 12 rotates the blade 10 in a rotation direction RD.

[0014] 2, the drive unit 12 is provided on the opposite side of the blade 10 to the airflow direction D1. That is, the drive unit 12 is provided on the upstream side of the blade 10. This example is not limiting, and the drive unit 12 may be provided on the airflow direction D1 side of the blade 10.

[0015] The annular portion 22 is positioned around the blade 10 in the XY plane. The annular portion 22 has an inner peripheral surface 22a facing the blade 10 and an outer peripheral surface 22b opposite to the inner peripheral surface 22a.

[0016] Fig. 3 is a side view showing a part of the fan according to the embodiment, in which the cross-sectional structure of the bell mouth is shown. 3, a staircase structure 23 is provided on the inner peripheral surface 22a of the annular portion 22. The staircase structure 23 is positioned around the blade 10 in the XY plane.

[0017] The staircase structure 23 includes a plurality of steps 23a arranged along the Z direction. Each step 23a is formed along the circumferential direction on the inner circumferential surface 22a. A step 23b is formed between adjacent steps 23a in the Z direction. The distance between each step 23a and the rotation axis R of the blade 10 increases toward the airflow direction D1. In other words, the opening surrounded by the staircase structure 23 widens toward the airflow direction D1.

[0018] The outer peripheral surface 22b is inclined with respect to the Z direction so that the thickness of the annular portion 22 is substantially constant. The outer peripheral surface 22b does not have a stepped structure. Alternatively, the outer peripheral surface 22b may have a stepped structure similar to that of the inner peripheral surface 22a.

[0019] The advantages of the embodiment will be described. It is desirable for fans to have high airflow efficiency. Airflow efficiency can be expressed using the PQ characteristic, which is expressed as the product of the airflow volume and static pressure when the fan is operating. For example, even if the airflow volume is constant, the PQ characteristic can be improved by increasing the static pressure.

[0020] FIG. 4 is a schematic diagram showing a part of a fan according to a reference example. In the fan 1r according to the reference example shown in FIG. 4, the inner circumferential surface 22a of the annular portion 22 does not have a stepped structure. The inner circumferential surface 22a is flat in the airflow direction D1. When the fan 1r is operating, the blades 10 send air in the airflow direction D1. At this time, a forward flow F1 and a reverse flow F2 are generated in the gap between the blades 10 and the annular portion 22. The forward flow F1 is an air flow in the airflow direction D1. The reverse flow F2 is an air flow in the opposite direction to the forward flow F1. If the flow rate of the reverse flow F2 is large, the static pressure decreases and the PQ characteristics deteriorate. For this reason, it is desirable that the flow rate of the reverse flow F2 is small.

[0021] 5(a) and 5(b) are schematic diagrams showing a part of the fan according to the embodiment. As described above, in the fan 1 according to this embodiment, the bellmouth 20 is provided with a staircase structure 23. As shown in FIG. 5(a), the staircase structure 23 has substantially no effect on the forward flow F1. On the other hand, as shown in FIG. 5(b), the backflow F2 is obstructed by the steps 23b of the staircase structure 23. This reduces the flow rate of the backflow F2 and increases its static pressure. As a result, the PQ characteristics can be improved.

[0022] FIG. 6 shows simulation results showing the characteristics of the fans according to the reference example and the embodiment. In Figure 6, the horizontal axis represents the flow rate (m 3 / h). The vertical axis represents static pressure (Pa). The solid line represents the characteristics of fan 1 according to the embodiment. The dashed line represents the characteristics of fan 1r according to the reference example. The conditions for the simulation of Figure 6 are as follows: The diameter of blade 10 is 58 cm. The inclination θ1 (shown in Figure 3) of inner circumferential surface 22a with respect to the Z direction is 3 degrees. The inclination θ1 corresponds to the angle between line segment L and the Z direction. Line segment L is obtained by connecting one end E1 and the other end E2 of staircase structure 23 in the Z direction. The inclination θ2 of outer circumferential surface 22b with respect to the Z direction is 3 degrees.

[0023] When compared at the same flow rate, the higher the static pressure, the better the PQ characteristics. As can be seen from FIG. 6, the fan 1 according to the embodiment has a higher static pressure than the fan 1r according to the reference example at any flow rate. In other words, the fan 1 according to the embodiment has better PQ characteristics than the fan 1r according to the reference example. According to the embodiment, the air blowing efficiency of the fan can be improved.

[0024] Although a portion of blade 10 may be outside the area surrounded by staircase structure 23, at least a portion of staircase structure 23 must be positioned around blade 10 in the XY plane. If the entire staircase structure 23 is positioned outside the periphery of blade 10, the effect of suppressing backflow F2 cannot be obtained.

[0025] FIG. 7 is a schematic diagram showing the manufacturing process of a bell mouth. The bell mouth 20 can be produced by injection molding. For example, as shown in FIG. 7, two molds, M1 and M2, are used. When mold M1 and mold M2 are fitted together in the Z direction, a space SP corresponding to the shape of the bell mouth 20 is formed. Resin Re is injected into the space SP from an injection port IN. After the space SP is filled with resin Re, the resin Re is cured. In this way, the bell mouth 20 is produced. Then, mold M1 and mold M2 are separated from the bell mouth 20.

[0026] 3, the inner peripheral surface 22a (step structure 23) and the outer peripheral surface 22b of the annular portion 22 are not parallel to the Z direction but are inclined relative to the Z direction. e After hardening, when the dies M1 and M2 are separated from the bell mouth 20 in the Z direction, friction can be reduced, making it easier to separate the dies M1 and M2.

[0027] The greater the inclination θ1 of the inner circumferential surface 22a relative to the Z direction, the easier it is to separate the mold M1 from the bell mouth 20. From the perspective of ease of separation of the mold M1 and the bell mouth 20, it is preferable that the inclination θ1 be greater than 2 degrees. On the other hand, if the inclination θ1 is too large, the gap between the blade 10 and the inner circumferential surface 22a on the other end E2 side will become too large, and the PQ characteristics may deteriorate excessively. From the perspective of the air blowing efficiency of the fan 1, it is preferable that the inclination θ1 be less than 5 degrees.

[0028] Similarly, the inclination θ2 of the outer peripheral surface 22b with respect to the Z direction is preferably greater than 2 degrees from the viewpoint of facilitating separation of the mold M2 and the bell mouth 20. The upper limit of the inclination θ2 is arbitrary, but if the difference between the inclinations θ1 and θ2 is excessively large, portions of the annular portion 22 will be thicker than necessary, and an excessive amount of resin Re will be used.

[0029] Preferably, each step 23a in the staircase structure 23 is also inclined with respect to the Z direction. The inclination of the steps 23a with respect to the Z direction is smaller than the inclination θ1. The inclination of the steps 23a with respect to the Z direction is preferably greater than 0 degrees and less than 0.5 degrees. The inclination of the steps 23a makes it easier to separate the mold M1 from the bell mouth 20.

[0030] (First Modification) FIG. 8 is a schematic diagram showing a fan according to a first modified example of the embodiment. In the fan 1a according to the first modification, the staircase structure 23 is formed in a spiral shape centered on the rotation axis R. The spiral is formed such that the steps 23a rotate in the rotation direction RD of the blades 10 as they move toward the airflow direction D1.

[0031] FIG. 9 is a schematic diagram showing the characteristics of a fan according to a first modified example of the embodiment. When the blade 10 rotates, a backflow F3 is generated along the blade 10, as shown in FIG. 9. The greater the flow rate of the backflow F3, the greater the decrease in static pressure. By providing a spiral shape, in the fan 1a according to the first modification, a step 23b is formed so as to intersect with the direction of the backflow F3. This makes it easier for the air in the backflow F3 to hit the step 23b. By obstructing the backflow F3, the static pressure can be further increased. According to the first modification, the air blowing efficiency can be further improved compared to the fan 1.

[0032] (Second Modification) FIG. 10 is a schematic diagram showing a fan according to a second modified example of the embodiment. In the fan 1b according to the second modification, as shown in FIG. 10, the length in the Z direction of the steps 23a of the staircase structure 23 increases toward the direction D2 opposite to the airflow direction D1.

[0033] For example, the multiple steps 23a include a step 23a1 and a step 23a2. The step 23a1 is located on the opposite side of the step 23a2 in the direction D2. The length La1 of the step 23a1 in the Z direction is longer than the length La2 of the step 23a2 in the Z direction.

[0034] The gap between the blades 10 and the staircase structure 23 is narrower on the upstream side of the annular portion 22 than on the downstream side. The longer the narrow gap portion is in the Z direction, the easier it is to increase the static pressure. By increasing the length of the steps 23a in the Z direction in the opposite direction D2, the narrow gap portion is lengthened, and the static pressure can be increased. According to the second modification, the air blowing efficiency can be further improved compared to the fan 1.

[0035] (Third Modification) FIG. 11 is a schematic diagram showing a fan according to a third modified example of the embodiment. In a fan 1c according to the third modification, as shown in FIG. 11, the steps 23b in the staircase structure 23 become smaller in the opposite direction D2.

[0036] For example, the staircase structure 23 includes steps 23b1 and 23b2. The step 23b1 is located on the opposite side of the step 23b2 in the direction D2. The size Lb1 of the step 23b1 is smaller than the size Lb2 of the step 23b2.

[0037] The gap between the blades 10 and the staircase structure 23 is narrower on the upstream side of the annular portion 22 than on the downstream side. The narrower the gap, the easier it is to increase the static pressure. The size of the step 23b decreases in the opposite direction D2, making it possible to further narrow the gap. For example, compared to fan 1, the distance between the step 23a2 between the steps 23b1 and 23b2 and the blades 10 can be made shorter. As a result, the static pressure in fan 1c can be increased. According to the third modification, the air blowing efficiency can be further improved compared to fan 1.

[0038] (Fourth Modification) FIG. 12 is a schematic diagram showing a fan according to a fourth modified example of the embodiment. 12, in fan 1d according to the fourth modification, the length of step 23a in the Z direction increases in the opposite direction D2, and step 23b decreases in the opposite direction D2. By combining the structure of fan 1b according to the second modification with the structure of fan 1c according to the third modification, the air blowing efficiency can be further improved.

[0039] Although several embodiments of the present invention have been described above, these embodiments are presented by way of example only and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, modifications, etc. can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, as well as within the scope of the invention and its equivalents as set forth in the claims. Furthermore, the above-described embodiments can be implemented in combination with each other. [Explanation of symbols]

[0040] 1, 1a to 1d, 1r: fan, 10: blade, 11: plate, 12: drive unit, 20: bell mouth, 21: base, 22: annular portion, 22a: inner peripheral surface, 22b: outer peripheral surface, 23: staircase structure, 23a, 23a1, 23a2: steps, 23b, 23b1, 23b2: step difference, D1: blowing direction, D2: opposite direction, E1: one end, E2: other end, F1: forward flow, F2, F3: reverse flow, IN: inlet, L: line segment, M1, M2: mold, R: rotation axis, RD: rotation direction, SP: space, θ1, θ2: tilt

Claims

1. a blade that rotates around a rotation axis along a first direction; a bellmouth including a staircase structure located around the blade along a first plane perpendicular to the first direction, the staircase structure being formed so that an opening surrounded by the staircase structure widens in the air blowing direction by the blade; Equipped with the staircase structure is formed in a spiral shape centered on the rotation axis, A fan in which the steps of the staircase structure rotate in a direction opposite to the rotation direction of the blades as they move toward the air blowing direction.

2. the bell mouth includes an annular portion that surrounds the blade along the first surface, the annular portion has an inner circumferential surface facing the blade, The fan according to claim 1 , wherein the step structure is provided on the inner circumferential surface.

3. the annular portion has an outer circumferential surface opposite the inner circumferential surface, The fan according to claim 2 , wherein the outer circumferential surface is inclined with respect to the first direction.

4. The fan according to claim 3 , wherein the inclination of the outer peripheral surface with respect to the first direction is greater than 2 degrees and less than 5 degrees.

5. the staircase structure includes a plurality of steps; 5. The fan according to claim 1, wherein the length of each of the plurality of stages in the first direction increases as it goes in a direction opposite to the air blowing direction.

6. The fan of claim 5 , wherein each of the plurality of stages is inclined with respect to the first direction.

7. The staircase structure has a plurality of steps formed therein, 7. The fan according to claim 1, wherein the plurality of steps become smaller as they extend in a direction opposite to the airflow direction.

8. The bell mouth includes a first opening and a second opening, The direction from the first opening to the second opening is along the air blowing direction, 8. The fan according to claim 1, wherein the second opening has a larger diameter than the first opening.

9. The bell mouth includes a plate-shaped base, 5. The fan according to claim 2, wherein the base portion is provided around the annular portion along the first surface and is positioned on the airflow direction side of the fan.

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