Fans and indoor units

Abstract

The fan (1) includes: a cross-flow impeller (8), a mechanism for rotating the cross-flow impeller (8) around a rotation axis (16), a front side tongue (14) disposed on the front side of the cross-flow impeller (8), and a back side tongue (15) disposed on the back side of the cross-flow impeller (8). The front side tongue (14) opposite to the cross-flow impeller (8) has: a plurality of front side concave and convex portions (58) with concave and convex shapes and a portion without concave and convex shapes. The convex front side flat portion (59) and the back side tongue portion (15) opposite to the cross-flow impeller (8) have: a plurality of back side concave and convex portions (65) with concave and convex shapes and a plurality of back side flat portions (66) without concave and convex shapes. The plurality of back side concave and convex portions (65) are respectively opposite to the plurality of front side flat portions (59), and the plurality of back side flat portions (66) are respectively opposite to the plurality of front side concave and convex portions (58).

Description

Technical Field

[0001] The technology disclosed herein relates to fans and indoor units. Background Technology

[0002] An indoor unit of an air conditioner is known to include a fan that delivers air by rotating a cross-flow impeller with multiple blades. The housing for housing the cross-flow impeller has a tongue disposed next to the impeller (see Patent Documents 1 to 5). To reduce blade noise generated between the cross-flow impeller and the tongue, the tongue is formed with various irregularities.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2014-70519

[0004] Patent Document 2: Japanese Patent Application Publication No. 2014-70756

[0005] Patent Document 3: Japanese Patent Application Publication No. 2014-70755 is based on

[0006] Patent Document 4: Japanese Patent Application Publication No. 2014-152724

[0007] Patent Document 5: Japanese Patent Application Publication No. 2014-190543 Summary of the Invention

[0008] This type of fan also has the following problem: surge occurs when the air flow rate is within a certain range, which reduces the air delivery performance.

[0009] The technology of the present invention was made in view of the above-mentioned problems, and its object is to provide a fan and an indoor unit that can reduce the noise generated between the cross-flow impeller and the tongue according to the blade setting interval, while suppressing the decline in air supply performance.

[0010] One aspect of the fan disclosed herein includes: a cross-flow impeller, a mechanism for rotating the cross-flow impeller about a rotation axis, a front side tongue disposed on the front side of the cross-flow impeller, and a back side tongue disposed on the back side of the cross-flow impeller. The front side tongue, on its front side impeller-facing surface opposite to the cross-flow impeller, includes: a plurality of front side convex and concave portions formed with irregularities, and a plurality of front side flat portions without irregularities. The back side tongue, on its back side impeller-facing surface opposite to the cross-flow impeller, includes: a plurality of back side convex and concave portions formed with irregularities, and a plurality of back side flat portions without irregularities. The plurality of back side convex and concave portions are respectively opposite to the plurality of front side flat portions across the cross-flow impeller. The plurality of back side flat portions are respectively opposite to the plurality of front side convex and concave portions across the cross-flow impeller.

[0011] The fan and indoor unit disclosed herein can suppress the increase in noise level while suppressing the decrease in air supply performance. Attached Figure Description

[0012] Figure 1 This is a cross-sectional view showing an indoor unit equipped with the fan of the embodiment.

[0013] Figure 2 This is a perspective view of the fan in an embodiment.

[0014] Figure 3 This is a three-dimensional view showing the portion of the front side tongue corresponding to the two impellers.

[0015] Figure 4 It is a three-dimensional view showing the part of the back side tongue that is opposite to the two impellers.

[0016] Figure 5 It is a three-dimensional diagram showing the front and back sides of the tongue. Detailed Implementation

[0017] The fan and indoor unit according to the embodiments disclosed in this application will now be described with reference to the accompanying drawings. However, the technology disclosed herein is not limited to the following description. Furthermore, in the following description, the same structural elements are labeled with the same symbols, and repeated descriptions are omitted.

[0018] Example

[0019] like Figure 1 As shown, in this embodiment, the fan 1 is installed in the indoor unit 10 of the air conditioner. Figure 1 This is a cross-sectional view showing an indoor unit 10 equipped with a fan 1 according to an embodiment. The air conditioner includes an indoor unit 10 and an outdoor unit (not shown). The outdoor unit is located outdoors. The indoor unit 10 is mounted on the wall of an air-conditioned room isolated from the outdoors. The indoor unit 10 includes a fan 1, a housing 2, and a heat exchanger 3. A ventilation duct 5 is formed inside the housing 2. An air inlet 6 is formed at the top of the housing 2, which connects the ventilation duct 5 to the outside of the housing 2. The heat exchanger 3 is disposed in the ventilation duct 5. The fan 1 is disposed in the lower region inside the housing 2 and in the downstream region of the heat exchanger 3 in the ventilation duct 5.

[0020] The fan 1 includes a fan housing 7 and a cross-flow impeller 8. The fan housing 7 is located downstream of the heat exchanger 3 in the ventilation duct 5 and is fixed to or integrally formed with the housing 2. The fan housing 7 has an air supply duct 11 and an air outlet 12. The air supply duct 11 is formed inside the fan housing 7. One end of the air supply duct 11 communicates with the area between the fan 1 and the heat exchanger 3 in the ventilation duct 5. The air outlet 12 is located at the lower end of the fan housing 7. The other end of the air supply duct 11 is connected to the air outlet 12 and communicates with the outside of the housing 2 of the indoor unit 10 via the air outlet 12.

[0021] A cross-flow impeller 8 is disposed in the air supply duct 11. The fan housing 7 has a front side tongue 14 and a rear side tongue 15. The front side tongue 14 is disposed on the front side of the air supply duct 11. The rear side tongue 15 is disposed on the rear side of the air supply duct 11.

[0022] Figure 2 This is a perspective view of the fan 1 according to an embodiment. The cross-flow impeller 8 is formed in a generally cylindrical shape. The cross-flow impeller 8 is disposed in the air supply duct 11 along the length direction (axial direction 35 in the figure) of the fan housing 7, and is supported on the fan housing 7 in a manner that allows it to rotate about the rotation axis 16. The cross-flow impeller 8 includes a plurality of impellers 31, a plurality of baffles 32, a first end plate 33, and a second end plate 34. The plurality of impellers 31 are arranged along an axial direction 35 parallel to the rotation axis 16, and are fixed to each other via the plurality of baffles 32. Figure 1 As shown, one of the plurality of impellers 31, impeller 36, has a plurality of blades 41. Each of the plurality of blades 41 is streamlined. The plurality of blades 41 are arranged in a circumferential direction centered on the axis of rotation 16. Each of the plurality of blades 41 is configured along a straight line parallel to the axis of rotation 16. Other impellers in the plurality of impellers 31, different from impeller 36, also have a plurality of blades 41 in the same manner as impeller 36.

[0023] Multiple partitions 32 are each formed into a roughly circular plate shape. For example... Figure 2 As shown, a plurality of baffles 32 are respectively arranged along a plurality of planes orthogonal to the rotation axis 16. Each of the plurality of baffles 32 is disposed between two impellers of a plurality of impellers 31 and is fixed to a plurality of blades 41 of the two impellers.

[0024] The first end plate 33 is formed in a generally circular plate shape. The first end plate 33 is disposed at one end of the cross-flow impeller 8 along a plane orthogonal to the rotation axis 16, and is fixed to multiple blades 41 of the first impeller 37 disposed at one end of the plurality of impellers 31. The second end plate 34 is formed in a generally circular plate shape. The second end plate 34 is disposed at the other end of the cross-flow impeller 8 along a plane orthogonal to the rotation axis 16, and is fixed to multiple blades 41 of the second impeller 38 disposed at the other end of the plurality of impellers 31. A third impeller 36, different from the first impeller 37 and the second impeller 38, is disposed between the first impeller 37 and the second impeller 38.

[0025] The fan 1 also includes a motor unit (not shown). The motor unit is for controlling the cross-flow fan wheel 8 as... Figure 1 The mechanism shown rotates around the rotation axis 16 along a predetermined rotation direction 40. Each of the plurality of impellers 31 is configured such that when the cross-flow fan 8 rotates along the rotation direction 40, it causes air to flow in the air supply duct 11 toward the air outlet 12.

[0026] Figure 3 This is a perspective view showing the portion of the front side tongue 14 corresponding to the two impellers. The position of the portion of the front side tongue 14 corresponding to the two impellers in the axial direction 35 is the same as the position of the two impellers in the axial direction 35. The front side tongue 14 includes a main body portion 51, a tip portion 52, and a stepped portion 53. The main body portion 51 forms a front side impeller facing surface 54. The front side impeller facing surface 54 is formed approximately along the side of a cylinder with the rotation axis 16 as its central axis. The front side impeller facing surface 54 faces the cross-flow impeller 8 and faces the back side tongue 15 across the cross-flow impeller 8. The front end portion 52 is the portion formed at the upper end of the front side tongue 14 and is disposed on the upper side of the main body portion 51. The front end portion 52 forms a front side impeller facing surface 55 facing the cross-flow impeller 8. The front-side impeller facing surface 55 is configured such that the distance between the front-side impeller facing surface 55 and the rotation axis 16 is longer than the distance between the front-side impeller facing surface 54 and the rotation axis 16, and is positioned further forward than the front-side impeller facing surface 54.

[0027] The front end portion 52 also has a plurality of protrusions 56. The plurality of protrusions 56 are formed in such a way that the upper end of the front end portion 52 is serrated. That is, the plurality of protrusions 56 are formed such that they protrude upward from the upper end of the front side tongue 14 and are arranged along the axial direction 35 at predetermined intervals. Furthermore, the plurality of protrusions 56 are also formed such that one of the protrusions 56 is formed in the portion of the front side tongue 14 corresponding to an impeller.

[0028] A stepped portion 53 is formed between the main body portion 51 and the front end portion 52 of the front side tongue portion 14. In the stepped portion 53, a stepped surface 57 is formed along a straight line parallel to the rotation axis 16. The stepped surface 57 is connected to the front side impeller opposite surface 54 and to the front side impeller opposite surface 55.

[0029] The front-side impeller facing surface 54 includes a plurality of front-side protruding portions 58 and a plurality of front-side flat portions 59. The plurality of front-side protruding portions 58 and the plurality of front-side flat portions 59 are arranged alternately along the axial direction 35, such that one of the front-side flat portions 59 is positioned between two of the protruding portions 58. That is, the plurality of front-side protruding portions 58 are arranged at predetermined intervals along the axial direction 35, such that one of the protruding portions 58 is formed in the portion of the front-side tongue 14 corresponding to the impeller 36. The plurality of front-side flat portions 59 are arranged at predetermined intervals along the axial direction 35, such that one of the front-side flat portions 59 is formed in the portion of the front-side tongue 14 corresponding to one impeller.

[0030] Each of the plurality of front-side protrusions 58 has a plurality of grooves. The grooves are formed by recessing from the front-side impeller opposing surface 54 and along a plurality of parallel lines. The parallel lines are parallel to the plane along which the front-side impeller opposing surface 54 is located and orthogonal to the rotation axis 16. Each of the plurality of front-side flat portions 59 is formed smoothly along the side surface of a cylinder centered on the rotation axis 16 without any protrusions or depressions.

[0031] Figure 4 This is a perspective view showing the portion of the back-side tongue 15 opposite to the two impellers. The position of the portion of the back-side tongue 15 corresponding to the two impellers along the axial direction 35 is the same as the position of the two impellers along the axial direction 35. The back-side tongue 15 has a front end portion 61 and a main body portion 62. The front end portion 61 is the portion formed at the upper end of the back-side tongue 15. The front end portion 61 has a plurality of protrusions 63. The plurality of protrusions 63 are formed in such a way that the upper end of the front end portion 61 is serrated. That is, the plurality of protrusions 63 are formed such that they protrude upward from the upper end of the back-side tongue 15 and are arranged along the axial direction 35 at predetermined intervals. Furthermore, the plurality of protrusions 63 are also formed such that one of the protrusions 63 is formed in the portion of the back-side tongue 15 corresponding to one impeller.

[0032] The main body 62 has a rear-side impeller facing surface 64. The rear-side impeller facing surface 64 is formed approximately along the side of a cylinder centered on the rotation axis 16. The rear-side impeller facing surface 64 faces the cross-flow impeller 8 and, across the cross-flow impeller 8, faces the front side tongue 14. The rear-side impeller facing surface 64 includes a plurality of rear-side protrusions and depressions 65 and a plurality of rear-side flat portions 66. The plurality of rear-side protrusions and depressions 65 and the plurality of rear-side flat portions 66 are arranged alternately along the axial direction 35, such that one of the rear-side flat portions 66 is positioned between two of the rear-side protrusions and depressions 65. That is, the plurality of rear-side protrusions and depressions 65 are arranged at predetermined intervals along the axial direction 35, such that one of the rear-side protrusions and depressions 65 is formed in the portion of the rear-side tongue 15 corresponding to one impeller. Multiple back-side flat portions 66 are arranged along the axial direction 35 at predetermined intervals, such that one of the multiple back-side flat portions 66 is formed in the portion of the back-side tongue 15 corresponding to an impeller 36.

[0033] Each of the plurality of back-side protrusions 65 has a plurality of grooves. The grooves are formed in a manner that recesses from the back-side impeller-facing surface 64 along a plurality of parallel lines. The parallel lines are parallel to the plane along which the back-side impeller-facing surface 64 is located and perpendicular to the rotation axis 16. Each of the plurality of back-side flat portions 66 is formed smoothly along the side of a cylinder centered on the rotation axis 16 without any protrusions or depressions.

[0034] Figure 5 This is a perspective view showing the front side tongue 14 and the rear side tongue 15. The rear side impeller facing surface 64 is formed such that a plurality of rear side concave-convex portions 65 are opposite to a plurality of front side flat portions 59 of the front side tongue 14, and a plurality of rear side flat portions 66 are opposite to a plurality of front side concave-convex portions 58 of the front side tongue 14. That is, the positions of the plurality of rear side concave-convex portions 65 in the axial direction 35 are the same as the positions of the plurality of front side flat portions 59 in the axial direction 35. The positions of the plurality of rear side flat portions 66 in the axial direction 35 are the same as the positions of the plurality of front side concave-convex portions 58 in the axial direction 35.

[0035] air conditioner operation

[0036] The air conditioner circulates refrigerant between the indoor unit 10 and the outdoor unit. The outdoor unit allows the refrigerant to exchange heat with the outside air. The fan 1 rotates the cross-flow fan 8 around the rotating shaft 16 in the rotation direction 40. Through the rotation of the cross-flow fan 8, the fan 1 supplies air from the air-conditioned room from the air inlet 6 of the indoor unit 10 to the ventilation duct 5. The heat exchanger 3 allows heat exchange between the air supplied from the air inlet 6 to the ventilation duct 5 and the refrigerant to adjust the temperature of the air supplied to the ventilation duct 5. Then, the air, whose temperature has been adjusted by the heat exchanger 3, is blown out from the air outlet 12 into the air-conditioned room. Through the above operation, the air conditioner can cool or heat the air-conditioned room where the indoor unit 10 is located.

[0037] Because the front tongue 14 of the fan 1 has a stepped surface 57, it can suppress turbulence of the air entering the air supply duct 11, thereby reducing noise generation. Because the front end of the front tongue 14 of the fan 1 has multiple protrusions 56, it can further suppress turbulence of the air entering the air supply duct 11, thereby reducing noise generation. Because the front end of the rear tongue 15 of the fan 1 has multiple protrusions 63, it can further suppress turbulence of the air entering the air supply duct 11, thereby reducing noise generation.

[0038] Between the front side impeller face 54 and the cross-flow impeller 8, when the cross-flow impeller 8 rotates and passes near the front side impeller face 54, that is, because each of the multiple blades 41 sometimes approaches the front side impeller face 54 and sometimes moves away from it, pressure fluctuations occur. Blade noise is generated here due to these pressure fluctuations. Blade noise, also known as nz noise, is a noise component with a fundamental frequency of number of blades × rotational speed. In addition to the front side blade noise, the noise component also includes front side wind noise caused by airflow turbulence between the cross-flow impeller 8 and the front side heat exchanger 3. The frequency of the front side wind noise varies depending on the airflow velocity between the cross-flow impeller 8 and the front side heat exchanger 3. The front side wind noise includes front side concave-convex side wind noise and front side flat side wind noise. The front side flat side wind noise is different from the front side concave-convex side wind noise. Specifically, due to the presence of multiple front-side irregularities 58, compared to a flat case (multiple front-side flat portions 59), a portion (groove) with a larger gap distance between itself and the cross-flow impeller 8 is formed. The larger this distance, the lower the airflow velocity. The frequency of the front-side wind noise varies with the flow velocity, thus the frequency of the front-side flat-side wind noise differs from the frequency of the front-side irregularity wind noise. If the front-side impeller opposite surface 54 is flat from one end to the other along the axial direction 35, and does not form a groove shape like the multiple front-side irregularities 58, then in the front-side heat exchanger 3, wind noise of a certain frequency is generated from one end to the other along the axial direction 35, increasing the noise level, and further increasing the noise level when it is at the same frequency as the blade noise. According to the technology of this disclosure, the portion that becomes a sound source resonating with the blade noise can be reduced, thus lowering the noise based on resonance. In wind turbine 1, since the wind noise on the concave-convex side of the front side is different from the wind noise on the flat side of the front side, the part that becomes the sound source that resonates with the blade noise can be reduced, thereby suppressing the increase of noise level.

[0039] Back-side wind noise is generated between the opposite surface 64 of the back-side impeller and the cross-flow impeller 8 due to airflow turbulence. The frequency of the back-side wind noise varies depending on the airflow velocity between the cross-flow impeller 8 and the back-side heat exchanger 3. The back-side wind noise includes back-side concave-convex side wind noise and back-side flat side wind noise. The back-side flat side wind noise is different from the back-side concave-convex side wind noise. Specifically, due to the presence of multiple back-side concave-convex portions 65, compared to the flat case (multiple front-side flat portions 66), a portion (groove) with a larger gap distance between the back-side wind noise and the cross-flow impeller 8 is formed. The larger this distance, the lower the airflow velocity, and the frequency of the wind noise varies according to the flow velocity; therefore, the frequency of the back-side flat side wind noise is different from the frequency of the back-side concave-convex side wind noise. Specifically, due to the presence of multiple back-side concave-convex portions 65, compared to the flat case (multiple front-side flat portions 66), a portion (groove) with a larger gap distance between the back-side wind noise and the cross-flow impeller 8 is formed; the larger this distance, the lower the airflow velocity. The frequency of the back side crosswind noise varies with the flow velocity, and therefore the frequency of the back side flat crosswind noise differs from the frequency of the back side concave-convex crosswind noise. Similar to the front side crosswind noise, the portion of the noise that becomes a source of resonance with the blade noise can be reduced, thus lowering the noise based on resonance. In fan 1, because the back side concave-convex crosswind noise differs from the back side flat crosswind noise, the portion of the noise that becomes a source of resonance with the blade noise can be reduced, thereby suppressing the increase in noise level.

[0040] Effect of fan 1 in the embodiment

[0041] The fan 1 of this embodiment includes: a cross-flow impeller 8, a mechanism for rotating the cross-flow impeller 8 about a rotation axis 16, a front side tongue 14 disposed on the front side of the cross-flow impeller 8, and a back side tongue 15 disposed on the back side of the cross-flow impeller 8. The front side tongue 14, on its front side impeller-facing surface 54 opposite to the cross-flow impeller 8, includes: a plurality of front side uneven portions 58 with irregularities, and a plurality of front side flat portions 59 without irregularities. The back side tongue 15, on its back side impeller-facing surface 64 opposite to the cross-flow impeller 8, includes: a plurality of back side uneven portions 65 with irregularities, and a plurality of back side flat portions 66 without irregularities. The plurality of back side uneven portions 65 are respectively opposite to the plurality of front side flat portions 59 across the cross-flow impeller 8. The plurality of back side flat portions 66 are respectively opposite to the plurality of front side uneven portions 58 across the cross-flow impeller 8.

[0042] The fan 1 of this embodiment has irregularities formed on both the front tongue 14 and the rear tongue 15. This allows for staggering the generation points of blade noise between the cross-flow impeller 8 and the front tongue 14, thus reducing the noise level. The multiple front-side irregularities 58 and the multiple rear-side irregularities 65 have a large gap distance (groove) with the cross-flow impeller 8, resulting in a reduction in airflow velocity. If the multiple front-side irregularities 58 and the multiple rear-side irregularities 65 are opposite each other, the airflow velocity will decrease excessively, causing airflow instability and potentially leading to surge. In the fan 1 of this embodiment, the multiple front-side irregularities 58 are opposite to the multiple front-side flat portions 66, and the multiple front-side flat portions 59 are opposite to the multiple rear-side irregularities 65. This prevents surge and suppresses the decrease in airflow performance.

[0043] Furthermore, multiple grooves are formed on the multiple front-side protrusions 58 and multiple rear-side protrusions 65 of the fan 1 in the above embodiment, recessed from the front-side impeller-facing surface 54 or the rear-side impeller-facing surface 64. However, other structures different from the multiple grooves can also be formed. As an example of such other structures, multiple ribs protruding from the front-side impeller-facing surface 54 or the rear-side impeller-facing surface 64 can be given. In short, any structure that makes the gap distance between the front-side tongue 14 (rear-side tongue 15) and the cross-flow impeller 8 different from the multiple front-side flat portions 59 (multiple rear-side flat portions 66) is acceptable. Fans with such structures, like the fan 1 in the above embodiment, can also suppress the decline in air delivery performance while reducing blade noise.

[0044] Furthermore, in the cross-flow impeller 8 of the fan 1 in the above embodiment, each of the plurality of impellers 31 faces one of the plurality of front-side protrusions 58, but may also face two or more of the plurality of front-side protrusions 58. Similarly, each of the plurality of impellers 31 faces one of the plurality of back-side protrusions 65, but may also face two or more of the plurality of back-side protrusions 65. A fan in which each of the plurality of impellers 31 faces two or more front-side protrusions and two or more back-side protrusions, similar to the fan 1 in the above embodiment, can suppress the increase in noise level while suppressing the decrease in air delivery performance.

[0045] Furthermore, in this embodiment, the front end of the front tongue 14 and the front end of the rear tongue 15 of the fan 1 have irregularities. In this case, the fan 1 of this embodiment can suppress turbulence of the air entering the air supply duct 11, thereby reducing noise generation. Additionally, while the front ends of the front tongue 14 and the rear tongue 15 of the fan 1 of the above embodiment have irregularities, they may not. A fan without irregularities at the front ends of the front tongue 14 and the rear tongue 15, like the fan 1 of the above embodiment, can also suppress the increase in noise level while suppressing the decrease in air supply performance.

[0046] Furthermore, a stepped surface 57 is formed on the front side impeller-facing surface 54 of the fan 1 in this embodiment, running along a straight line parallel to the rotation axis 16. Because the fan 1 in this embodiment has the stepped surface 57, air flowing into the space between the front side impeller-facing surface 54 and the stepped surface 57 forms tiny vortices. These tiny vortices can suppress turbulence in the airflow entering the air supply duct 11, reducing noise generation. Additionally, multiple grooves can be formed around the junction of the stepped surface 57 of the front side tongue 14 and the front side impeller-facing surface 55 of the fan 1 in this embodiment. A fan with these multiple grooves can further suppress turbulence in the airflow entering the air supply duct 11, further reducing noise generation.

[0047] Furthermore, in the above embodiment, the fan 1 has a stepped surface 57 formed between the front side impeller facing surface 54 and the front end impeller facing surface 55. However, it is also possible that no step is formed between the front side impeller facing surface 54 and the front end impeller facing surface 55. That is, both the front side impeller facing surface 54 and the front end impeller facing surface 55 can be formed along the side of a cylinder with the rotation axis 16 as the central axis. A fan without a stepped portion between the front side impeller facing surface 54 and the front end impeller facing surface 55 can, like the fan 1 in the above embodiment, suppress the increase in noise level while suppressing the decrease in air delivery performance.

[0048] Furthermore, while the fan 1 described in the above embodiment is used in the indoor unit 10 of an air conditioner, it can also be used in other devices different from the indoor unit 10. An example of such a device is an air curtain device. In this case, the fan 1 can also suppress the increase in noise level and the decrease in air delivery performance.

[0049] The embodiments described above are examples, but the embodiments are not limited to the above content. Furthermore, the structural elements described above include structural elements that are readily conceived by those skilled in the art, substantially the same, and within the so-called equivalent range. Moreover, the structural elements described above can be appropriately combined. Furthermore, at least one of various omissions, substitutions, and modifications can be made to the structural elements without departing from the spirit of the embodiments.

[0050] Symbol Explanation

[0051] 1: Fan, 2: Casing, 3: Heat exchanger, 7: Fan casing, 8: Cross-flow fan, 10: Indoor unit, 11: Air supply duct, 12: Air outlet, 14: Front side tongue, 15: Rear side tongue, 16: Rotating shaft, 31: Multiple impellers, 35: Axial direction, 41: Multiple blades, 54: Front side impeller opposite face, 58: Multiple front side concave and convex parts, 59: Multiple front side flat parts, 64: Rear side impeller opposite face, 65: Multiple rear side concave and convex parts, 66: Multiple rear side flat parts.

Claims

1. A fan, characterized in that, include: Crossflow wind turbine; A mechanism that causes the cross-flow fan wheel to rotate around a rotating axis; The front tongue is disposed on the front side of the cross-flow impeller; as well as The rear side tongue is configured on the rear side of the cross-flow impeller. The front side tongue portion, opposite to the cross-flow impeller, has the following features: Multiple front-side concave and convex portions are formed; as well as Multiple flat front sides without any unevenness. The rear side tongue portion, opposite to the cross-flow impeller, has the following features: Multiple uneven portions are formed on the back side; as well as Multiple flat portions on the back side without any unevenness. The plurality of concave and convex portions on the rear side are respectively opposite to the plurality of flat portions on the front side, separated by the cross-flow impeller. The plurality of flat portions on the back side are respectively opposite to the plurality of concave and convex portions on the front side, separated by the cross-flow impeller.

2. The fan according to claim 1, characterized in that, The plurality of front-side convex and concave portions form grooves that are recessed from the opposite side of the front-side impeller. The plurality of rear-side protrusions and recesses form grooves that are recessed from the opposite side of the rear-side impeller.

3. The fan according to claim 1, characterized in that, The cross-flow wind turbine has multiple impellers arranged parallel to the rotation axis. Each of the plurality of impellers is opposite to at least one of the plurality of front-side protrusions and concavities, and is also opposite to at least one of the plurality of back-side protrusions and concavities.

4. The fan according to claim 1, characterized in that, The front side impeller has a stepped portion formed on the opposite surface along a straight line parallel to the axis of rotation. The stepped portion has a plurality of protrusions and concave surfaces arranged parallel to the axis of rotation.

5. An indoor unit, characterized in that, include: Heat exchanger; as well as The fan of claim 1 delivers air after it has passed through the heat exchanger.

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