Axial flow fan

Abstract

To provide an axial flow fan capable of improving air blow efficiency.SOLUTION: An axial fan 1 for blowing air in an air blow direction W includes an impeller cup 3 having a blade 5 extending in a radial direction, a motor for rotating the impeller cup 3, and a housing 2 storing the impeller cup 3 and the motor. The housing 2 includes a casing 21 covering an outer periphery of the impeller cup 3, a base 9 supporting the motor, and a spoke 10 connecting the base 9 and the casing 21. The casing 21 includes a suction surface sucking the air, and a discharge surface 23b discharging the air. A step 24 is provided on at least a part of the discharge surface 23b side of an inner peripheral surface of the casing 21.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to an axial fan.

Background Art

[0002] Conventionally, in an axial fan, from the viewpoint of material reduction and product quality during molding, the frame has been hollowed out. For example, Patent Document 1 discloses an axial fan provided with a hollowed-out portion on the suction surface side of the frame.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, providing a hollowed-out portion in the frame may affect the air flow in the axial fan. Therefore, the position where the hollowed-out portion of the frame is provided is important. However, the axial fan of Patent Document 1 does not disclose the relationship between the position where the hollowed-out portion is provided and the air flow. Therefore, there is room for improvement in the relationship between the position where the hollowed-out portion of the frame is provided and the air blowing efficiency of the fan.

[0005] Therefore, an object of the present invention is to provide an axial fan capable of improving the air blowing efficiency.

Means for Solving the Problems

[0006] The axial fan according to one aspect of the present invention is an axial fan that blows air in the air blowing direction, an impeller cup having blades extending in the radial direction, a motor that rotates the impeller cup, The impeller cup and the housing that houses the motor, Equipped with, The aforementioned housing is The casing portion covers the outer circumference of the impeller cup, The base portion that supports the motor, It has spokes connecting the base portion and the casing portion, The casing portion is, The intake surface that draws in air, It has a discharge surface that expels air, A stepped portion is provided on at least a part of the inner circumferential surface of the casing portion on the discharge surface side.

[0007] An axial flow fan according to one aspect of the present invention is An axial flow fan that blows air in the direction of airflow, An impeller cup having radially extending blades, A motor that rotates the impeller cup, The impeller cup and the housing that houses the motor, Equipped with, The aforementioned housing is The casing portion covers the outer circumference of the impeller cup, The base portion that supports the motor, It has spokes connecting the base portion and the casing portion, The casing portion is, The intake surface that draws in air, It has a discharge surface that expels air, On the discharge surface of the casing portion, a weight-reducing portion is opened at a position that is off-center from the longitudinal extension of the spoke portion. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide an axial flow fan that can improve airflow efficiency. [Brief explanation of the drawing]

[0009] [Figure 1]It is a perspective view of the air discharge side of the axial fan according to an embodiment of the present invention. [Figure 2] It is a perspective view of the axial fan shown in FIG. 1 as viewed from the air suction side. [Figure 3] It is a cross-sectional view taken along the line A-A of the axial fan shown in FIG. 1. [Figure 4] It is a partially enlarged view showing the stepped portion and the hollowed portion of the casing portion. [Figure 5] It is a perspective view schematically showing the air flow on the discharge port side in the axial fan. [Figure 6] It is a cross-sectional view schematically showing the air flow on the discharge port side in the axial fan. [Figure 7] It is a graph showing the relationship between the air volume and the static pressure characteristics, and the relationship between the air volume and the power consumption in the axial fan of the present invention and the axial fan of the comparative example.

Mode for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the embodiments, members having the same reference numerals as those already described will be omitted for the sake of convenience of explanation. In addition, the dimensions of each member shown in the drawings may be different from the actual dimensions of each member for the sake of convenience of explanation.

[0011] FIG. 1 is a perspective view of the axial fan according to an embodiment of the present invention as viewed from the air discharge side. FIG. 2 is a perspective view of the axial fan shown in FIG. 1 as viewed from the air suction side. As shown in FIGS. 1 and 2, the axial fan 1 according to the embodiment includes a housing 2, an impeller cup 3 disposed in the housing 2, and a motor 7 that rotationally drives the impeller cup 3. The impeller cup 3 has a plurality (in this example, seven) of blades 5. The motor 7 is housed inside the cup of the impeller cup 3.

[0012] The housing 2 has an overall polygonal shape (rectangular in this example). The housing 2 has a cylindrical casing portion 21 that covers the outer circumference of the impeller cup 3, a base portion 9 that supports the motor 7 housed in the impeller cup 3, spoke portions 10 that connect the base portion 9 and the casing portion 21, and corner portions 11 that form a rectangle. The housing 2 is made of resin.

[0013] The casing section 21 has an intake port 21a (the front casing opening in Figure 2) for drawing in air and an outlet port 21b (the front casing opening in Figure 1) for expelling the drawn-in air. The casing section 21 forms an air passage 22 that communicates with the intake port 21a and the outlet port 21b. As the blade 5 rotates, the air drawn in from the intake port 21a is sent in a direction along the air passage 22 (hereinafter referred to as the airflow direction W) and discharged to the outside from the outlet port 21b. The casing section 21 also has an intake surface 23a provided on the outer circumference of the intake port 21a and a discharge surface 23b provided on the outer circumference of the outlet port 21b. Figure 1 is a perspective view of the axial flow fan 1 as seen from the outlet port 21b side of the casing section 21. Figure 2 is a perspective view of the axial flow fan 1 as seen from the intake port 21a side of the casing section 21. The direction of arrow V shown in the figure indicates the rotation direction of wing 5.

[0014] Figure 3 is a cross-sectional view of the axial flow fan 1 shown in Figure 1 along line AA. As shown in Figure 3, the cup 30 of the impeller cup 3 has its center fixed to the rotating shaft 70 of the motor 7. In the following description, the direction along the rotating shaft 70 is referred to as the "axial direction," and the radial direction centered on the rotating shaft 70 is referred to as the "radial direction."

[0015] The rotating shaft 70 is positioned in the center of the air passage 22, aligned with the air passage 22 (airflow direction W). The impeller cup 3 is fixed to the rotating shaft 70, with the opening side of the cup 30 facing the discharge port 21b of the air passage 22, and aligned with the air passage 22. The radial outer peripheral surface 31 of the cup 30 forms the inner peripheral surface on the intake port 21a side of the air passage 22. The outer peripheral surface 31 of the cup 30 is formed to extend parallel to the airflow direction W. The impeller cup 3, having blades 5, rotates together with the rotating shaft 70 within the air passage 22, thereby sending air in the airflow direction W.

[0016] Multiple wings 5 ​​are provided so as to extend radially from the outer peripheral surface 31 of the cup 30. The wings 5 ​​are integrally provided with the cup 30. Each of the multiple wings 5 ​​is provided at an angle with respect to the direction of the rotation axis 70.

[0017] The motor 7 is housed within the cup 30 of the impeller cup 3 as a device for rotating the blade 5. The motor 7 has a roughly cup-shaped rotor yoke 71, a rotating shaft 70 pressed into the center of the rotor yoke 71, and a stator core 81 around which a coil 82 is wound.

[0018] The rotor yoke 71 is fitted into the cup 30 of the impeller cup 3 and rotates together with the rotating shaft 70. A magnet 72 is attached to the inner surface of the rotor yoke 71. The rotating shaft 70 is rotatably supported by a bearing 73. The bearing 73 is fixed to the inner surface of a cylindrical support portion 74. A stator core 81 is fixed to the outer surface of the support portion 74. The outer surface of the stator core 81 faces the inner surface of the magnet 72 of the rotor yoke 71, separated by a gap.

[0019] Furthermore, the stator core 81 of the motor 7 is attached to the base portion 9. The base portion 9 is formed in a roughly cup shape. The base portion 9 is positioned so that its opening faces the opening of the cup 30 of the impeller cup 3 on the discharge port 21b side of the air passage 22. The central part of the base portion 9 is attached to the stator core 81 of the motor 7 and is also fixed to the outer surface of the support portion 74. The radially outer peripheral surface 91 of the base portion 9 forms the inner peripheral surface on the discharge port 21b side of the air passage 22. The base portion 9 is provided coaxially with the air passage 22 in the central part of the air passage 22.

[0020] The spokes 10 connecting the base portion 9 and the casing portion 21 are provided on the discharge port 21b side of the housing 2. Multiple spokes 10 are provided at approximately equal intervals in the circumferential direction of the base portion 9. The base portion 9 and the motor 7 attached to the base portion 9 are supported by the casing portion 21 by the multiple spokes 10.

[0021] The casing portion 21 has a stepped portion 24 on the discharge surface 23b side of the inner circumferential surface 21c. The stepped portion 24 is provided on a part of the inner circumferential surface 21c in the circumferential direction. The casing portion 21 also has a weight-reducing portion 25 on the discharge surface 23b. The weight-reducing portion 25 is formed parallel to the airflow direction W, extending from the discharge surface 23b toward the suction surface 23a. The stepped portion 24 and the weight-reducing portion 25 will be described further in Figure 4.

[0022] A flange portion 26 is provided on the periphery of the corner portion 11 of the housing 2 for fixing the housing 2 to electronic equipment or the like. The flange portion 26 extends radially outward from the suction surface 23a and discharge surface 23b of the casing portion 21. A fixing hole 27 is formed in the flange portion 26 so as to penetrate the housing 2. The axial flow fan 1 can be attached to electronic equipment or the like by, for example, inserting a screw into this fixing hole 27.

[0023] Figure 4 is a partially enlarged view showing the stepped portion 24 and the weight-reducing portion 25 of the casing portion 21. As shown in Figure 4, the stepped portion 24 is formed in a shape that recesses from the discharge surface 23b toward the suction surface 23a along the air passage 22 on the inner circumferential surface 21c. In this example, the stepped portion 24 is formed to be a rectangular recess. If, for example, a tapered portion 21d that expands in diameter toward the discharge surface 23b is provided at the end of the inner circumferential surface 21c of the casing portion 21 on the discharge surface 23b side, as shown in the figure, it is preferable that the stepped portion 24 has the same length (depth) as the length of the tapered portion 21d along the air passage 22.

[0024] The weight-reducing portion 25 is formed in a part of the discharge surface 23b. The discharge surface 23b is located on the outer circumference of the discharge port 21b, but the area of ​​the region located at the corner 11 of the housing 2 is larger than, for example, the area of ​​the region located on the side of the housing 2. The weight-reducing portion 25 is formed on the discharge surface 23b located at the corner 11 of the housing 2, extending toward the center of the ventilation passage 22 (rotation axis 70). In a plan view perpendicular to the discharge surface 23b, the weight-reducing portion 25 opens, for example, in a rectangular shape.

[0025] The stepped portion 24 and the weight-reducing portion 25 are located near the corner portion 11. Furthermore, the stepped portion 24 and the weight-reducing portion 25 are located off-center from the longitudinal extension of the spoke portion 10. In other words, the position where the radial outer end of the spoke portion 10 connects to the casing portion 21 is different from the position where the stepped portion 24 and the weight-reducing portion 25 are formed on the casing portion 21. Each spoke portion 10 is connected to a position circumferentially spaced away from the position where the stepped portion 24 and the weight-reducing portion 25 are formed.

[0026] The stepped portion 24 is provided between the weight-reducing portion 25 and the ventilation passage 22, which is an internal opening of the casing portion 21. The weight-reducing portion 25 is connected to the ventilation passage 22 of the casing portion 21 via the stepped portion 24. That is, the radial inner end of the weight-reducing portion 25, which is formed to face the center of the ventilation passage 22, is connected to the stepped portion 24 formed on the inner circumferential surface 21c of the casing portion 21, and is connected to the ventilation passage 22 of the casing portion 21. The stepped portion 24 and the weight-reducing portion 25 are provided on the discharge surface 23b of each corner portion 11, respectively.

[0027] Figure 5 is a schematic perspective view showing the airflow on the discharge port 21b side of the axial flow fan 1. Figure 6 is a schematic cross-sectional view showing the airflow on the discharge port 21b side of the axial flow fan 1. As shown in Figure 5, by providing a stepped portion 24 and a weight-reducing portion 25 in the casing portion 21, it is possible to make the airflow in the stepped portion 24 and the weight-reducing portion 25 a vortex flow, for example, as shown by arrow B. This makes it possible to reduce the resistance to the airflow outside the stepped portion 24 and the weight-reducing portion 25, for example, the resistance to the airflow as shown by arrow C, and to make the airflow on the discharge port 21b side a smooth flow.

[0028] Furthermore, as shown in Figure 6, by providing a stepped portion 24 and a weight-reducing portion 25 in the casing portion 21, it is possible to make the airflow in the stepped portion 24 and the weight-reducing portion 25 uneven, as shown by arrow D, for example. This allows the airflow near the inner circumferential surface 21c of the casing portion 21 to be guided toward the stepped portion 24, as shown by arrow E, for example, and makes it possible to create a smooth airflow toward the outside of the housing on the discharge port 21b side.

[0029] As described above, the axial flow fan 1 according to the embodiment of the present invention is provided with a stepped portion 24 on at least a portion of the inner circumferential surface 21c of the casing portion 21 on the discharge surface 23b side. With this configuration, the stepped portion 24 forms a vortex of air, which reduces the resistance of the air flowing near the inner circumferential surface 21c of the casing portion 21. This improves the airflow efficiency of the axial flow fan 1.

[0030] Furthermore, the axial flow fan 1 has a weight-reducing section 25 on the discharge surface 23b of the casing section 21, at a position that is off-center from the longitudinal extension of the spoke section 10. With this configuration, the weight-reducing section 25 forms a space into which air flowing near the inner circumferential surface 21c of the casing section 21 flows. This reduces the resistance of the air flowing near the inner circumferential surface 21c, thereby improving the airflow efficiency of the axial flow fan 1. In addition, by providing the weight-reducing section 25 at a position that is off-center from the longitudinal extension of the spoke section 10, the housing 2 can be easily lightened during manufacturing.

[0031] Furthermore, the axial flow fan 1 has a stepped portion 24 between the weight-reducing portion 25 and the air passage 22 of the casing portion 21, and the weight-reducing portion 25 and the air passage 22 are connected by the stepped portion 24. By providing the stepped portion 24 between the weight-reducing portion 25 and the air passage 22 in this way, the air flowing near the inner circumferential surface 21c of the casing portion 21 can flow more easily into the weight-reducing portion 25. This reduces the resistance of the air flowing near the inner circumferential surface 21c, thereby improving the airflow efficiency of the axial flow fan 1. In addition, it becomes possible to reduce the thickness between the weight-reducing portion 25 and the air passage 22 of the casing portion 21, making it even easier for air to flow into the weight-reducing portion 25.

[0032] Furthermore, in a plan view along the airflow direction W, the axial flow fan 1 has a polygonal shape in which the housing 2 has multiple corners 11, and stepped portions 24 and weight-reducing portions 25 are provided near each of the multiple corners 11. By providing the stepped portions 24 and weight-reducing portions 25 near the corners 11 in this way, the dead space (discharge surface 23b) present in the corners 11 can be utilized, preventing the axial flow fan 1 from becoming too large.

[0033] Next, we will describe the results of tests conducted to confirm the improvement in the airflow efficiency of the axial flow fan 1 of the present invention. Figure 7 is a graph showing the relationship between airflow rate and static pressure characteristics, and the relationship between airflow rate and power consumption, for the axial flow fan 1 of the present invention and the axial flow fan of the comparative example. The axial flow fan of the comparative example was an axial flow fan that did not have the stepped portion 24 and the weight-reducing portion 25 of the axial flow fan 1 of the present invention.

[0034] As shown in Figure 7, comparing the airflow-static pressure characteristics, the performance of the axial flow fan 1 of the present invention in the operating range of the axial flow fan is, for example, airflow of 2.0 to 3.8 [m³]. 3 The performance of the axial flow fan 1 of the present invention at [ / min] can be improved compared to the performance of the comparative axial flow fan. Furthermore, when comparing airflow-power consumption, the power consumption of the axial flow fan 1 of the present invention can be reduced by approximately 5% compared to the power consumption of the comparative axial flow fan. The tests were conducted with a rotational speed of 3050 rpm for each axial flow fan.

[0035] Although embodiments of the present invention have been described above, it goes without saying that the technical scope of the present invention should not be interpreted as being limited by the description of these embodiments. These embodiments are merely examples, and it will be understood by those skilled in the art that various modifications to the embodiments are possible within the scope of the invention described in the claims. The technical scope of the present invention should be determined based on the scope of the invention described in the claims and the scope of its equivalents.

[0036] In the embodiments described above, a case was explained in which a single stepped portion 24 and a weight-reducing portion 25 are provided at the corner 11 of the housing 2, but the invention is not limited to this. For example, multiple stepped portions 24 and weight-reducing portions 25 may be provided at the corner 11 of the housing 2.

[0037] Furthermore, although the above-described embodiment described an example in which the stepped portion 24 is a rectangular recess along the air passage 22 on the inner circumferential surface 21c, the invention is not limited to this. For example, the shape of the stepped portion 24 may be semicircular, oval, or the like. In addition, although the example described in which the weight-reducing portion 25 is formed in a rectangular shape in a plan view perpendicular to the discharge surface 23b, the invention is not limited to this. For example, the shape of the weight-reducing portion 25 may be circular, oval, or the like. [Explanation of symbols]

[0038] 1 Axial flow fan 2 Housing 3 Impeller Cups 5 wings 7 Motor 9 Base section 10 Spoke section 11 corners 21 Casing section 21a Inlet 21b Discharge port 21c Inner surface 21d Tapered section 22 Ventilation duct 23a Suction surface 23b Discharge surface 24 Stepped section 25. Weight reduction section 26 Flange section 27 Fixing hole 30 cups W Airflow direction

Claims

1. An axial flow fan that blows air in the direction of airflow, An impeller cup having radially extending blades, A motor that rotates the impeller cup, The impeller cup and the housing that houses the motor, Equipped with, The aforementioned housing is The casing portion covers the outer circumference of the impeller cup, The base portion that supports the motor, It has spokes connecting the base portion and the casing portion, The casing portion is, The intake surface that draws in air, It has a discharge surface that expels air, The aforementioned discharge surface is A mounting section having a fixing hole for fixing to the object to be attached, A flat portion located on the suction surface side of the mounting portion, It has a tapered portion located on the inner diameter side of the flat portion, A stepped portion is provided on a part of the inner circumferential surface of the casing portion on the discharge surface side, The stepped portion is provided so as to span from the tapered portion to the flat portion, in an axial flow fan.

2. The axial flow fan according to claim 1, wherein at least a portion of the discharge surface of the casing is provided with a weight-reducing portion.

3. The axial flow fan according to claim 2, wherein the weight-reducing portion is provided at a position that is off the longitudinal extension of the spoke portion.

4. The housing has a polygonal shape including multiple corners in a plan view perpendicular to the airflow direction. The axial flow fan according to claim 2, wherein the stepped portion and the weight-reducing portion are provided near each of the multiple corner portions.

5. An axial flow fan that blows air in the direction of airflow, An impeller cup having radially extending blades, A motor that rotates the impeller cup, The impeller cup and the housing that houses the motor, Equipped with, The aforementioned housing is The casing portion covers the outer circumference of the impeller cup, The base portion that supports the motor, It has spokes connecting the base portion and the casing portion, The casing portion is, The intake surface that draws in air, It has a discharge surface that expels air, The aforementioned discharge surface is A mounting section having a fixing hole for fixing to the object to be attached, A flat portion located on the suction surface side of the mounting portion, It has a tapered portion located on the inner diameter side of the flat portion, On the discharge surface of the casing portion, a weight-reducing portion is opened at a position that is off-center from the longitudinal extension of the spoke portion. The aforementioned weight-reducing section opens to span from the tapered section to the flat section, in an axial flow fan.

6. The axial flow fan according to claim 5, wherein a stepped portion is provided on at least a part of the inner circumferential surface of the casing portion on the discharge surface side.

7. The housing has a polygonal shape including multiple corners in a plan view perpendicular to the airflow direction. The axial flow fan according to claim 6, wherein the stepped portion and the weight-reducing portion are provided near each of the multiple corner portions.

8. An axial flow fan according to any one of claims 2 to 4, 6, or 7, wherein the stepped portion is provided between the weight-reducing portion and the internal opening of the casing portion, and the weight-reducing portion and the internal opening are connected.

9. The axial flow fan according to claim 1, wherein the stepped portion is formed in the shape of a slit extending in the radial direction.

10. The axial flow fan according to claim 5, wherein the opening of the weight-reducing portion is a slit extending in the radial direction.

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