Reversible Fan

Abstract

To provide a reversible fan of which a noise level during blowing in a positive direction and a noise level during blowing in a reverse direction are made equal to each other by enhancing the noise level during blowing in the positive direction.SOLUTION: A reversible fan 1 for generating an air flow both in a positive direction and in a reverse direction includes an impeller 2 rotatable around a rotation axis X, a motor 3 for rotating the impeller 2, and a cylindrical frame 5 extending along the rotation axis X and storing the impeller 2, and the motor 3. Fins 10 having such a shape that a magnitude of noise to be generated for the air flow in the positive direction is greater than a magnitude of noise to be generated for the air flow in the reverse direction, are provided protruding from an inner peripheral face of the frame 5 to a radial inside.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a reversible fan. [Background technology]

[0002] 2. Description of the Related Art A reversible fan that generates airflow in both forward and reverse directions is known, as disclosed in Patent Document 1 and the like. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6802022 Summary of the Invention [Problem to be solved by the invention]

[0004] By the way, such a reversible fan may be attached to the wall of a house, for example, and used to raise the room temperature by taking in outside air when the outside air is warmer, and to lower the room temperature by expelling indoor air when the indoor temperature is high. In this case, if the noise generated when taking in outside air differs from the noise generated when expelling indoor air, residents may suspect that the fan is broken.

[0005] When equivalent noise characteristics are required when blowing air in the forward and reverse directions, the general idea is to reduce the noise level when blowing air in the reverse direction to match the low noise level when blowing air in the forward direction.

[0006] However, contrary to this idea, the inventor realized that, depending on the application, it would be possible to make the noise levels of both the forward and reverse directions equal by increasing the noise level during forward and reverse blowing. For example, in the above-mentioned application, since the noise levels during forward and reverse blowing are not equal, equipment failure would be suspected, but even if the noise levels during forward and reverse blowing are constantly high, equipment failure would not be suspected.

[0007] Therefore, an object of the present invention is to provide a reversible fan in which the noise level during forward blowing is increased so that the noise level during forward blowing is equal to the noise level during reverse blowing. [Means for solving the problem]

[0008] A reversible fan according to one aspect of the present invention includes: A reversible fan that generates airflow in both forward and reverse directions, An impeller rotatable about a rotation axis; A motor that rotates the impeller; a cylindrical frame that houses the impeller and the motor; Fins shaped to generate greater noise in response to a forward airflow than in response to a reverse airflow are provided so as to protrude radially inward from the inner circumferential surface of the frame. Effect of the Invention

[0009] According to the present invention, it is possible to provide a reversible fan in which the noise level during forward blowing is increased so that the noise level during forward blowing is equal to the noise level during reverse blowing. [Brief description of the drawings]

[0010] [Figure 1] 1 is a perspective view of a reversible fan according to an embodiment of the present invention, seen from the opposite direction. [Diagram 2] 2 is a partially enlarged view showing the fins in region A in FIG. 1. [Diagram 3] FIG. 3 is a cross-sectional view taken along line BB in FIG. [Figure 4] 11A and 11B are diagrams illustrating the flow of air around the fins when an airflow is generated in the forward direction. [Diagram 5] 11A and 11B are diagrams illustrating the flow of wind around the fins when an airflow is generated in the opposite direction. [Figure 6]FIG. 2 is a perspective view showing a first comparative example of a fin. [Figure 7] FIG. 11 is a perspective view showing a second comparative example of the fin. [Figure 8] FIG. 11 is a perspective view showing a third comparative example of a fin. [Figure 9] FIG. 13 is a perspective view showing a first modified example of the fin. [Figure 10] FIG. 11 is a cross-sectional view showing a second modified example of the fin. [Figure 11] FIG. 11 is a cross-sectional view showing a third modified example of the fin. [Figure 12] FIG. 11 is a cross-sectional view showing a fourth modified example of the fin. [Figure 13] FIG. 11 is a cross-sectional view showing a fifth modified example of the fin. [Figure 14] FIG. 13 is a diagram showing a sixth modified example of the fin. [Figure 15] FIG. 13 is a diagram showing a seventh modified example of the fin. [Figure 16] FIG. 13 is a diagram showing an eighth modified example of the fin. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. For the sake of convenience, the description of the components having the same reference numbers as those already described in the description of the embodiment will be omitted. Also, for the sake of convenience, the dimensions of each component shown in the drawings may differ from the actual dimensions of each component.

[0012] FIG. 1 is a perspective view of a reversible fan 1 according to an embodiment of the present invention. 1, reversible fan 1 includes an impeller 2 that is rotatable about a rotation axis X, a motor 3 that rotates the impeller 2, a base 4 that supports the motor 3, and a cylindrical frame 5 that houses these components. The impeller 2, motor 3, and base 4 are housed within frame 5 so as to overlap along the direction of the rotation axis X.

[0013] In this embodiment, the direction in which air (airflow) is discharged when the impeller 2 of the reversible fan 1 shown in Fig. 1 rotates in the direction of the arrow n (forward rotation direction) is referred to as the forward direction (direction of the arrow N) of the reversible fan 1. Also, the direction in which air (airflow) is discharged when the impeller 2 rotates in the direction of the arrow r (reverse rotation direction) is referred to as the reverse direction (direction of the arrow R) of the reversible fan 1.

[0014] The reversible fan 1 is a fan that can blow air (generate airflow) in both the forward and reverse directions.

[0015] The impeller 2 is formed in a generally cup shape. A plurality of blades 2a (five in the illustrated example) are attached radially around the periphery of the impeller 2. The blades 2a are attached to the impeller 2 in a state inclined with respect to the axial direction of the rotating shaft of the reversible fan 1 (the same direction as the rotation axis X). The impeller 2 generates an airflow in the forward or reverse direction by the rotation of the blades 2a.

[0016] The motor 3 is provided inside the impeller 2. The motor 3 is, for example, an outer rotor type brushless motor. The motor 3 has a stator and a rotor arranged on the outer periphery of the stator. The motor 3 inside the impeller 2 has a rotor portion fixed to the impeller 2. The motor 3 is assembled inside the impeller 2 so as to be located on the front side (positive direction side) of the impeller 2.

[0017] The base portion 4 is formed, for example, in a circular cup shape. The base portion 4 is provided so as to cover the front side of the motor 3. The base portion 4 supports a stator portion of the motor 3. The base portion 4 is assembled in the frame 5 so as to be disposed on the front side of the motor 3.

[0018] The base portion 4 is supported by a plurality of spokes 6. The spokes 6 each extend radially from the periphery of the base portion 4 and are connected to the inner circumferential surface of the frame 5. The base portion 4 supported by the spokes 6 is attached to a position close to the front side of the cylindrical frame 5 extending along the rotation axis X.

[0019] The frame 5 has a main body 51 forming a cylindrical portion, and flanges 52a, 52b provided on the outer periphery of both ends of the main body 51. The frame 5 is provided with a plurality of fins 10 protruding radially inward from the inner circumferential surface of the frame 5. When the number of blades 2a is five as in this example, the number of fins 10 is preferably, for example, 7 to 9 or 11 to 14. However, n times the number of blades (10 in the example shown in the figure) is excluded because sound resonance is likely to occur.

[0020] Next, the fins 10 provided on the frame 5 will be described with reference to FIGS. Fig. 2 is a partial enlarged view showing the fin 10 provided in region A in Fig. 1. Fig. 3 is a cross-sectional view taken along line BB in Fig. 2.

[0021] As shown in Figs. 2 and 3, the fin 10 is provided at an end of the main body 51 in the opposite direction (arrow R direction) in the direction of the rotation axis X of the frame 5. The fin 10 extends along the direction of the rotation axis X. A tapered surface 53 expanding in diameter in the opposite direction is provided on the inner periphery of the inner periphery of the end of the main body 51 in the opposite direction of the inner periphery of the frame 5. The fin 10 is provided so as to protrude from the tapered surface 53 of the main body 51, or to protrude from a surface in a range spanning the tapered surface 53 of the main body 51 and the inner periphery of the main body 51 continuing to the tapered surface 53. In the example shown in the figures, the tapered surface 53 of the main body 51 is formed to have a curved shape protruding radially inward.

[0022] The fins 10 are formed so that the width in the circumferential direction is, for example, 3° to 40° with respect to the inner peripheral surface of the frame 5. For example, when the diameter of the reversible fan 1 is 160 mm, the width of the fins 10 is formed so that the width is 3° to 7° with respect to the inner peripheral surface of the frame 5. When the diameter is 136 to 126 mm, the width is formed so that the width is 4° to 10°. When the diameter is 80 mm, the width is formed so that the width is 5° to 15°. When the diameter is 40 mm, the width is formed so that the width is 10° to 30°. Moreover, the fins 10 are formed so that the height of the fins 10 protruding radially inward is a height that does not contact the blades 2a of the impeller 2. Moreover, the fins 10 are formed so that the length in the direction of the rotation axis X is within a range that does not interfere with the orbit of the impeller 2.

[0023] The fin 10 has a first curved surface 11 constituting a surface in the forward rotation direction (arrow n direction), a second curved surface 12 constituting a surface in the reverse rotation direction (arrow r direction), and an edge portion 13 connecting the first curved surface 11 and the second curved surface 12. The first curved surface 11 is formed to be a curved surface that protrudes toward the forward rotation direction. The second curved surface 12 is formed to be a curved surface that is recessed in the forward rotation direction. In the example shown in the figure, the fin 10 is formed in a thin plate shape with the first curved surface 11 and the second curved surface 12 as the front and back surfaces.

[0024] A separation space 14, through which part of the airflow in a predetermined direction flows, is formed between the second curved surface 12 of the fin 10 and the inner circumferential surface of the frame 5 facing the second curved surface 12. In the example shown in the figure, the separation space 14 is formed between the second curved surface 12 of the fin 10 and the tapered surface 53 of the main body 51 of the frame 5.

[0025] Next, the airflow in the reversible fan 1 will be described with reference to Figures 4 and 5. Figure 4 is a diagram showing the airflow around the fins 10 when an airflow is generated in the forward direction in the reversible fan 1. Figure 5 is a diagram showing the airflow around the fins 10 when an airflow is generated in the reverse direction in the reversible fan 1.

[0026] For example, when the impeller 2 is rotated in the reverse rotation direction, part of the airflow generated in the reverse direction is separated at the end 13p in the reverse rotation direction of the edge 13 of the fin 10 and flows into the separation space 14. In addition, for example, when the impeller 2 is rotated in the forward rotation direction, part of the airflow generated in the forward direction flows into the separation space 14.

[0027] The fins 10 have openings that open in the forward rotation direction of the impeller and open to the forward airflow. That is, the fins 10 are formed so as to have a bulging shape toward the reverse airflow and a recessed shape toward the forward airflow. In other words, the fins 10 are formed so as to have a lower fluid resistance against the reverse airflow than against the forward airflow. The fins 10 are configured to generate noise when the airflow collides with the fins 10. The fins 10 are formed so as to generate a louder noise against the forward airflow than against the reverse airflow.

[0028] When the impeller 2 of the reversible fan 1 is rotated in the forward direction (the direction of the arrow n) to generate an airflow in the forward direction (the direction of the arrow N), the airflow entering from the opening in the reverse direction of the frame 5 enters the frame 5 while part of the airflow flows into the separation space 14 of the fin 10 provided at the end of the main body 51 in the reverse direction. For this reason, for example, as shown by the arrows C1 and C2, the airflow flowing into the separation space 14 is blown against the second curved surface 12 of the fin 10, causing the flow to become disturbed and preventing the air from being smoothly drawn into the frame 5. At this time, noise is generated due to the airflow being obstructed by the fin 10.

[0029] On the other hand, as shown in FIG. 5, when the impeller 2 of the reversible fan 1 is rotated in the reverse direction (arrow r direction) to generate an airflow in the reverse direction (arrow R direction), a part of the airflow that enters from the forward opening of the frame 5 collides with the first curved surface 11 of the fin 10 provided at the end of the main body 51 in the reverse direction when it flows out from the forward opening. The airflow that collides with the first curved surface 11 flows along the first curved surface 11 and flows smoothly without generating large noise. Furthermore, the airflow that flows along the first curved surface 11 is separated from the first curved surface 11 (circular arc portion) of the fin 10 by the end 13p of the edge portion 13 of the fin 10 into the separation space 14. As a result, for example, as shown by the arrows D1 and D2, a certain vortex (turbulence) 15 is generated in the separated airflow in the separation space 14, and the flow becomes regular and stable. This reduces noise caused by the airflow in the reverse direction.

[0030] In order to deepen understanding of the fin 10 of this embodiment, fins of first to third comparative examples, which have shapes in which the noise level during forward airflow and the noise level during reverse airflow are not equal to each other, unlike those of this embodiment, will be described with reference to Figs. 6 to 8.

[0031] 6 is a perspective view showing a fin 100 of a first comparative example. The fin 100 is formed as a linear protrusion that protrudes vertically from an inner circumferential surface 151 of a frame 150 toward the inside in the radial direction. However, in the case of the fin 100 configured in this way, since the surface of the fin 100 in the forward rotation direction (direction of arrow n) is configured as a flat surface, when the impeller is rotated in the reverse rotation direction (direction of arrow r) to generate an airflow in the reverse direction (direction of arrow R), the airflow is obstructed by the fin 100 as shown by arrows E1 and E2. As a result, the noise level increases when air is blown in the reverse direction, and the occurrence of a difference in noise level cannot be suppressed.

[0032] 7 is a perspective view showing a fin 200 of a second comparative example. The surface of the fin 200 in the forward rotation direction (arrow n direction) is curved like the fin 10 of the above embodiment, and the surface in the reverse rotation direction (arrow r direction) is flat like the fin 100 of the above first comparative example. In the case of the fin 200 having such a configuration, since the surface in the forward rotation direction of the fin 100 is curved, the noise level decreases slightly when the impeller is rotated in the reverse rotation direction to generate an airflow in the reverse direction (arrow R direction). However, since the surface in the reverse rotation direction of the fin 100 is flat, the noise level hardly increases when the impeller is rotated in the forward rotation direction to generate an airflow in the forward direction (arrow N direction), and the difference between the noise level when blowing air in the forward direction and the noise level when blowing air in the reverse direction cannot be reduced.

[0033] 8 is a perspective view showing a fin 300 of a third comparative example. The fin 300 is configured such that the surface in the forward rotation direction (arrow n direction) is curved like the fin 10 of the above embodiment, and the surface in the reverse rotation direction (arrow r direction) is curved and protrudes toward the reverse rotation direction. However, the separation space 14 like the fin 10 of the above embodiment is not provided. In the case of the fin 300 configured in this way, when the impeller is rotated in the forward rotation direction to generate an airflow in the forward direction (arrow N direction) and when the impeller is rotated in the reverse rotation direction to generate an airflow in the reverse direction (arrow R direction), the turbulence of the airflow becomes large, resulting in a high noise level when blowing air in both directions.

[0034] In contrast, in the reversible fan 1 according to this embodiment, the fins 10 are provided so as to protrude radially inward from the inner circumferential surface of the frame 5. The fin 10 has a first curved surface 11 that protrudes in the forward rotation direction and constitutes the forward rotation direction surface of the fin 10, a second curved surface 12 that is recessed in the forward rotation direction and constitutes the reverse rotation direction surface of the fin 10, and an edge portion 13 that connects the first curved surface 11 and the second curved surface 12. A separation space 14 is formed between the second curved surface 12 and the inner circumferential surface of the frame 5, which separates part of the flow at an end 13p in the reverse rotation direction of the edge portion 13 when the impeller 2 is rotated in the reverse rotation direction. Therefore, the airflow generated during forward rotation and flowing in the forward direction (forward direction) collides with the second curved surface 12. The airflow that collides with the second curved surface 12 is disturbed by the second curved surface 12, and the noise level increases. On the other hand, the airflow generated during reverse rotation and flowing in the reverse direction (reverse direction) collides with the first curved surface 11. The airflow that collides with the first curved surface 11 flows along the first curved surface 11, so the noise level does not increase. Furthermore, part of the airflow generated during reverse rotation is separated by the separation space 14 and forms a certain vortex. This makes it possible to stabilize the airflow during reverse rotation and suppress noise. In this way, by suppressing the noise level during reverse blowing and increasing the noise level during forward blowing, the noise level during forward blowing and the noise level during reverse blowing can be made equal.

[0035] Furthermore, with the reversible fan 1, the fins 10 are recessed toward the airflow in the forward direction and bulge toward the airflow in the reverse direction. That is, the fins 10 are configured so that the fluid resistance to the airflow in the reverse direction is lower than the fluid resistance to the airflow in the forward direction. As a result, the noise generated by the fins 10 in response to the airflow in the forward direction is greater than the noise generated by the airflow in the reverse direction. This makes it possible to make the noise levels of the forward and reverse directions equivalent. It is possible to make the noise levels of the forward and reverse directions equivalent without affecting the air volume and static pressure characteristics of the reversible fan 1 or the power consumption.

[0036] Furthermore, according to the reversible fan 1, a tapered surface 53 that expands in diameter in the opposite direction is formed at the end of the frame 5 on the opposite side in the direction of the rotation axis X, and the fins 10 are provided on the tapered surface 53 of the frame 5 so as to extend in the direction of the rotation axis X. This structure makes it easy to demold the frame 5 even though the fins 10 are provided.

[0037] (Modification) Next, modified examples of the fins will be described. Fig. 9 is a cross-sectional view showing a fin 10A of a first modified example. As shown in Fig. 9, the fin 10A is different from the fin 10 of the embodiment shown in Fig. 3 in that the cross-sectional shape of the separation space 14A is formed to be rectangular. The fin 10 is formed so that a surface 53A on the frame 5A side constituting the separation space 14A, i.e., the surface 53A facing the second curved surface 12A of the fin 10A, extends along the positive direction of the rotation axis X (the direction of the arrow N).

[0038] Fig. 10 is a cross-sectional view showing a fin 10B of a second modified example. As shown in Fig. 10, the fin 10B is different from the fin 10 of the embodiment shown in Fig. 3 in that the surface 53B on the frame 5B side constituting the peeling space 14B, i.e., the surface 53B facing the second curved surface 12B of the fin 10B, is formed as a curved surface recessed toward the outside in the radial direction, which is different from the fin 10 of the embodiment formed as a curved surface protruding toward the inside in the radial direction. Note that the shape of the curved surface recessed toward the outside in the radial direction may be provided only on the surface 53B facing the second curved surface 12B, or may be provided on a portion corresponding to the entire tapered surface 53 of the main body portion 51 of the frame 5 described in the embodiment.

[0039] Fig. 11 is a cross-sectional view showing a fin 10C of a third modified example. As shown in Fig. 11, the fin 10C differs from the fin 10B of the second modified example shown in Fig. 10 in that the extension direction of the fin 10C is inclined with respect to the direction of the rotation axis X. The fin 10C is inclined radially inward (direction away from the surface 53C of the frame 5C that constitutes the peeling space 14C) as it progresses in the opposite direction (the direction of the arrow R), which differs from the fin 10B of the second modified example that is provided to extend in the direction of the rotation axis X.

[0040] Fig. 12 is a cross-sectional view showing a fin 10D of a fourth modified example. As shown in Fig. 12, the fin 10D is the same as the fin 10C of the third modified example shown in Fig. 11 in that the fin 10D is formed to be inclined radially inward (in a direction away from the surface 53D of the frame 5D side that constitutes the peeling space 14D) as it proceeds in the opposite direction (the direction of the arrow R). However, the fin 10D is formed to have a curved surface that protrudes radially inward, which differs from the fin 10C of the third modified example that does not have such a curved surface.

[0041] Fig. 13 is a cross-sectional view showing a fin 10E of a fifth modified example. As shown in Fig. 13, the fin 10E is different from the fin 10D of the fourth modified example shown in Fig. 12 in that a surface 53E on the frame 5E side constituting the peeling space 14E, i.e., a surface 53E facing the second curved surface 12E of the fin 10E, is formed along the direction of the rotation axis X, and is therefore different from the fin 10D of the fourth modified example which is formed to be a curved surface recessed radially outward.

[0042] Fig. 14 is a diagram showing a fin 10F of a sixth modified example. As shown in Fig. 14, the fin 10F is different from the fin 10 of the embodiment shown in Fig. 2 in that a surface 53F on the frame 5F side constituting the peeling space 14F, i.e., a surface 53F facing the second curved surface 12F of the fin 10F, is formed along the direction of the rotation axis X, and thus differs from the fin 10 of the embodiment formed to have a curved surface that protrudes radially inward.

[0043] Fig. 15 is a diagram showing a fin 10G of a seventh modified example. As shown in Fig. 15, the fin 10G is different from the fin 10 of the embodiment shown in Fig. 2 in that a surface 53G on the frame 5G side constituting the peeling space 14G, i.e., a surface 53G facing the second curved surface 12G of the fin 10G, is formed by cutting out the peripheral wall of the frame 5G in an arc shape toward the outside in the radial direction, and thus differs from the fin 10 of the embodiment formed to have a curved surface protruding toward the inside in the radial direction.

[0044] Fig. 16 is a diagram showing a fin 10H of an eighth modified example. As shown in Fig. 16, the fin 10H is different from the fin 10 of the embodiment shown in Fig. 2 in that a surface 53H on the frame 5H side constituting the separation space 14H, i.e., a surface 53H facing the second curved surface 12H of the fin 10H, is formed by cutting out the peripheral wall of the frame 5H in a rectangular shape toward the outside in the radial direction, and thus differs from the fin 10 of the embodiment formed to have a curved surface protruding toward the inside in the radial direction.

[0045] According to the fins 10A to 10H of the above-mentioned modified examples, it is possible to secure large separation spaces 14A to 14H, respectively, and to increase the noise level during forward air blowing. As a result, the noise level during forward air blowing and the noise level during reverse air blowing can be made equal to each other.

[0046] Although the embodiment of the present invention has 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 the embodiment. The embodiment is merely an example, and it is understood by those skilled in the art that various modifications of the embodiment 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 its equivalents. [Explanation of symbols]

[0047] 1 Reversible Fan 2 Impeller 2a Feather 3 Motor 4 Base 5(5A~5H) Frame 6 spokes 10(10A~10H) Fins 11 First surface 12(12B,12E~12H) Second curved surface 13 Edge 13p end 14(14A~14H) Peeling space 15 Eddy (Turbulence) 51 Main body 52a, 52b Flange part 53 Tapered surface 53A~53H side n Positive rotation direction r Reverse rotation direction N positive direction R Reverse direction X rotation axis

Claims

1. A reversible fan that generates airflow in both forward and reverse directions, An impeller rotatable about a rotation axis; A motor that rotates the impeller; a cylindrical frame that houses the impeller and the motor; A reversible fan having fins shaped to generate greater noise in a forward airflow than in a reverse airflow, the fins protruding radially inward from the inner circumferential surface of the frame.

2. When the rotation direction of the impeller when generating an airflow in the positive direction is called a positive rotation direction, The reversible fan according to claim 1 , wherein the fins have openings that are open in the forward rotation direction of the impeller and open to the forward airflow.

3. When the rotation direction of the impeller when generating an airflow in the forward direction is called the forward rotation direction, and when the rotation direction of the impeller when generating an airflow in the reverse direction is called the reverse rotation direction, The fin is A first curved surface that constitutes the positive rotation direction surface of the fin and that protrudes toward the positive rotation direction; A second curved surface that constitutes the reverse rotation direction surface of the fin and is recessed in the forward rotation direction; an edge portion connecting the first curved surface and the second curved surface; 2. The reversible fan of claim 1, wherein a separation space is formed between the second curved surface and an inner circumferential surface of the frame, which separates a portion of the flow at an end of the edge portion in the reverse rotation direction when the impeller is rotated in the reverse rotation direction.

4. 2. The reversible fan according to claim 1, wherein the fins are provided at the opposite end of the frame with respect to the direction of the rotation axis.

5. a tapered surface that expands in diameter in the opposite direction is provided at the end of the frame in the opposite direction, The reversible fan according to claim 1 , wherein the fins extend in the direction of the axis of rotation.

6. The reversible fan according to claim 3 , wherein a portion of an inner circumferential surface of the frame facing the second curved surface of the fin is recessed radially outward.

Images