Axial flow fan air conditioner

Abstract

The utility model relates to a kind of axial flow fan and air conditioner, wherein axial flow fan includes hub and multiple blades;Blade includes: blade root, blade top, leading edge and trailing edge;Trailing edge is equipped with the gap extending towards leading edge direction;The side wall of gap includes first inclined wall and second inclined wall, first inclined wall and second inclined wall are located at the opposite sides of the gap, and the included angle between first inclined wall and second inclined wall is in the angle range of 67.7 °-71.7 °.Through trailing edge gap design, the continuous structure of blade trailing edge can be effectively destroyed, periodic vortex shedding at trailing edge is interfered and weakened, so as to realize vortex suppression, reduce high-frequency sound noise;Through the angle range of axial development angle between first inclined wall and second inclined wall is 67.7 °-71.7 °, the periodic shedding of vortex can be effectively disturbed, noise is dispersed and weakened, trailing edge gap noise reduction effect is improved, the problem of noise reduction of axial flow fan is solved.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning technology, and in particular to an axial flow fan and an air conditioner. Background Technology

[0002] An air conditioner is a device used to regulate indoor air temperature, humidity, airflow speed, and air cleanliness. It is widely used in homes, offices, commercial spaces, and industrial environments. Its basic principle is to transfer heat through the circulation of refrigerant, utilizing the physical processes of evaporation (absorbing heat) and condensation (releasing heat), thereby achieving a cooling or heating effect.

[0003] An axial fan is a component of the outdoor unit of an air conditioner. The rotation of the axial fan generates a directional flow of air that passes through the outdoor heat exchanger, where the air exchanges heat with the heat exchanger to dissipate heat.

[0004] Among axial fans, axial fans are relatively noisy, and how to reduce the noise of axial fans has become an urgent problem to be solved. Utility Model Content

[0005] The purpose of this invention is to provide an axial fan and an air conditioner to solve the problem of noise reduction of axial fans.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: According to one aspect of the present invention, an axial flow fan is provided, comprising: a hub; a plurality of blades spaced apart on the hub in a circumferential direction, each blade comprising: a blade root formed on the edge of the blade connected to the hub; a blade tip formed on the edge of the blade away from the hub; a leading edge formed on the edge of the blade at the windward end in the direction of rotation; and a trailing edge formed on the edge of the blade at the leeward end in the direction of rotation; the trailing edge having a notch extending toward the leading edge; wherein the sidewall of the notch comprises: a first inclined wall disposed on the side of the notch near the blade root; and a second inclined wall disposed on the side of the notch near the blade tip; the first inclined wall and the second inclined wall are disposed on opposite sides of the notch, and the included angle between the first inclined wall and the second inclined wall is an axial expansion angle, the axial expansion angle being in the range of 67.7°-71.7°.

[0007] The above-mentioned technical solution has the following advantages or beneficial effects: The trailing edge notch design effectively disrupts the continuous structure of the blade's trailing edge, interfering with and reducing the periodic vortex shedding at the trailing edge (Karman vortex street phenomenon), thereby achieving vortex suppression and reducing high-frequency noise. The first and second inclined walls on both sides of the notch, with an axial expansion angle between them ranging from 67.7° to 71.7°, effectively disrupt the periodic vortex shedding, dispersing and weakening noise, improving the trailing edge notch noise reduction effect, and solving the noise reduction problem of axial flow fans. Furthermore, if the axial expansion angle is too large, it can easily generate additional noise. For example, an excessively large notch can create strong local airflow separation and turbulence, forming a broadband noise source, and may even generate additional discrete-tone noise (such as whistling). If the axial expansion angle is too small, the noise reduction effect is weak, failing to effectively disrupt the periodic vortex shedding, and its effect on noise dispersion and weakening is limited, failing to achieve the expected noise reduction target.

[0008] In some embodiments of this application, the ratio of the chord length corresponding to the deepest part of the notch to the chord length corresponding to the tip of the leaf ranges from 0.52 to 0.56.

[0009] The above-mentioned technical solution has the following advantages or beneficial effects: by using a ratio of chord length corresponding to the deepest part of the notch to chord length corresponding to the tip of the blade in the range of 0.52-0.56, it can ensure that the notch has sufficient depth while avoiding excessive notch depth, thereby enabling the notch to effectively disrupt the formation of vortices at the trailing edge and improve the airflow field; while ensuring the fan air volume, it effectively reduces the fan power and noise.

[0010] In some embodiments of this application, the radius of the hub is R0, the radius of the blade tip is R1, and the radius of the deepest point of the notch is R2; then the ratio of the distance R2-R0 between the deepest point of the notch and the hub to the distance R1-R0 between the blade tip and the hub is in the range of 0.63-0.67.

[0011] The above-mentioned technical solution has the following advantages or beneficial effects: by setting the ratio of the distance between the deepest part of the notch and the hub to the distance between the blade tip and the hub in the range of 0.63-0.67, the notch can be close to the blade tip and maintain a certain distance from the blade tip, while also being far away from the blade root and hub. This can effectively disrupt the formation of vortices at the trailing edge, improve the airflow field, and reduce the power and noise of the fan.

[0012] In some embodiments of this application, the sidewall of the notch includes an arc-shaped wall located between the first inclined wall and the second inclined wall; one end of the arc-shaped wall is connected to the first inclined wall, and the other end is connected to the second inclined wall; the deepest part of the notch is located on the arc-shaped wall.

[0013] The above-mentioned technical solution has the following advantages or beneficial effects: the gap can be formed by the first inclined wall, the arc-shaped wall and the second inclined wall being connected in sequence, so that the first inclined wall and the second inclined wall can be smoothly connected through the arc-shaped wall, effectively disrupting the periodic shedding of the eddy current and ensuring the noise reduction effect of the eddy current noise.

[0014] In some embodiments of this application, a first thickened area is provided on the suction surface of the blade. The first thickened area is located on the periphery of the notch and in the connection area between the trailing edge and the blade tip. The edge of the first thickened area facing the leading edge is provided in an arc shape.

[0015] The above-mentioned technical solution has the following advantages or beneficial effects: The first thickened area can enhance both the structural strength at the notch and the structural strength of the connection area between the trailing edge and the blade tip, which helps reduce stress concentration, enhances the local strength of the blade, and avoids fatigue failure caused by long-term operation and stress concentration failure caused by drops during transportation. By thickening the trailing edge notch, vortex shedding can be controlled, broadband noise can be suppressed, and high-frequency vortex shedding noise can be reduced.

[0016] In some embodiments of this application, the angle between the line connecting one end of the arcuate edge of the first thickened area to the center of the arcuate wall and the line connecting the other end of the arcuate edge of the first thickened area to the center of the arcuate wall is the circumferential unfolding angle, and the circumferential unfolding angle ranges from 157° to 163°.

[0017] The above-mentioned technical solution has the following advantages or beneficial effects: by using a circumferential unfolding angle β with an angle range of 157°-163°, it can ensure that the arc edge of the first thickened area is large enough to surround the periphery of the gap and ensure the thickening effect on the gap area, while avoiding the arc edge of the first thickened area being too large and reducing costs.

[0018] In some embodiments of this application, the radius of the first thickened area near the end of the blade root is R3; the radius of the blade tip is R1; and the radius of the hub is R0. Then, the ratio of the distance R3-R0 between the end of the first thickened area near the blade root and the hub to the distance R1-R0 between the blade tip and the hub is in the range of 0.42-0.46.

[0019] The above-mentioned technical solution has the following advantages or beneficial effects: by making the ratio of the distance between the end of the first thickened area near the blade root and the hub to the distance between the blade tip and the hub range from 0.42 to 0.46, it can be ensured that the range of the first thickened area is large enough to surround the periphery of the notch, thus ensuring the thickening effect on the notch area, and also avoiding the radial position range of the first thickened area being too large, thereby avoiding increased costs.

[0020] In some embodiments of this application, a second thickened area is provided on the suction surface of the blade. The second thickened area is arranged along the edge of the leading edge, one end of the second thickened area is connected to the leaf root, and the other end of the second thickened area is spaced apart from the leaf tip.

[0021] The above-mentioned technical solution has the following advantages or beneficial effects: the second thickened zone can enhance the structural strength at the leading edge, which helps to reduce stress concentration, enhance the local strength of the blade, and avoid fatigue failure caused by long-term operation and stress concentration failure caused by drops during transportation. By thickening the leading edge, the local structural strength of the blade can be improved, and flow separation can be delayed.

[0022] In some embodiments of this application, the ratio of the chord length of the region where the second thickened area is connected to the leaf root to the chord length of the leaf root ranges from 0.18 to 0.22.

[0023] The above technical solution has the following advantages or beneficial effects: by setting 0.18≤C3 / C4≤0.22, the second thickened area can have sufficient width to ensure that the structural strength at the leading edge can be enhanced; at the same time, the width of the second thickened area can be avoided to prevent the cost from increasing.

[0024] According to one aspect of the present invention, the present invention also provides an air conditioner that includes the aforementioned axial fan.

[0025] The above-mentioned technical solution has the following advantages or beneficial effects: by including the above-mentioned axial flow fan in the air conditioner, the continuous structure of the trailing edge of the fan blades can be effectively destroyed, the periodic eddy current shedding at the trailing edge (Karman vortex street phenomenon) can be interfered with and weakened, thereby achieving eddy current suppression, reducing high-frequency noise of the fan, and solving the problem of noise reduction of axial flow fans. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of an axial fan according to some embodiments of this application.

[0027] Figure 2 yes Figure 1 A structural diagram from another perspective.

[0028] Figure 3 yes Figure 1 The front view.

[0029] Figure 4 yes Figure 3 A magnified view of the local structure.

[0030] Figure 5 yes Figure 4 Another structural diagram.

[0031] Figure 6 yes Figure 4 Another structural diagram.

[0032] Figure 7 yes Figure 2 The front view.

[0033] Figure 8 yes Figure 7 A magnified view of the local structure.

[0034] Figure 9 yes Figure 8 Another structural diagram.

[0035] Figure 10 yes Figure 8 Another structural diagram.

[0036] Figure 11 yes Figure 1 Side view.

[0037] The reference numerals in the attached drawings are explained as follows: 100, axial flow fan; 1, hub; 2, blade; 201, pressure surface; 202, suction surface; 21, blade root; 22, blade tip; 23, leading edge; 24, trailing edge; 241, notch; 2411, first inclined wall; 2412, second inclined wall; 2413, arc-shaped wall; 25, first thickened area; 251, arc-shaped edge; 26, second thickened area; 27, flange. Detailed Implementation

[0038] Typical embodiments embodying the features and advantages of this utility model will be described in detail in the following description. It should be understood that this utility model can have various variations in different embodiments, all of which do not depart from the scope of this utility model, and the descriptions and illustrations therein are for illustrative purposes only and not intended to limit this utility model.

[0039] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0042] Figure 1 This is a schematic diagram of the structure of an axial fan 100 according to some embodiments of this application. Figure 2 yes Figure 1 A structural diagram from another perspective.

[0043] like Figure 1 and Figure 2 As shown, the axial fan 100 provided in some embodiments of this application can be a component of the outdoor unit of an air conditioner. The rotation of the axial fan 100 generates directional airflow to pass through the outdoor heat exchanger, where the air exchanges heat with the heat exchanger to dissipate heat from the outdoor heat exchanger.

[0044] In some embodiments, the axial fan 100 may include a hub 1. The axial fan 100 rotates about the central axis of the hub 1, thereby generating airflow.

[0045] like Figure 1 and Figure 2 As shown, in some embodiments, the axial fan 100 may include blades 2, which are disposed on the outer peripheral wall of the hub 1. Multiple blades 2 may be provided, and these blades 2 may be spaced apart along the circumferential direction on the outer peripheral wall of the hub 1. The multiple blades 2 may be evenly arranged relative to the hub 1. In this embodiment, three blades 2 are provided. It should be noted that in other embodiments, the number of blades 2 may not be limited to three.

[0046] In some embodiments, the connection between the blade 2 and the hub 1 has a certain inclination arc, that is, the blade 2 is connected to the outer peripheral wall of the hub 1 after rotating at a certain angle, so that the outside air can flow along the axial direction of the axial fan 100.

[0047] Figure 3 yes Figure 1The front view. Figure 3 This is a side view of the axial fan 100 along the axial direction.

[0048] like Figure 3 As shown, in some embodiments, the blade 2 may include a blade root 21, which is formed at the edge where the blade 2 connects to the hub 1. The blade root 21 may be arranged spirally around the outer peripheral wall of the hub 1.

[0049] In some embodiments, the blade 2 may include a blade tip 22, which is formed at the outermost edge of the blade 2. The blade tip 22 may be formed at the edge of the blade 2 away from the hub 1.

[0050] In some embodiments, the blade 2 may include a leading edge 23, which is formed on the blade 2 at an edge extending outward from the outer peripheral wall of the wheel, and the leading edge 23 is formed at the edge of the windward end of the blade 2 in the direction of rotation.

[0051] In some embodiments, the blade 2 may include a trailing edge 24, which is formed on another edge of the blade 2 extending outward from the outer peripheral wall, and is formed at the leeward edge of the blade 2 in the direction of rotation. The leading edge 23 and the trailing edge 24 are located on opposite sides of the blade 2 in the direction of rotation. In the direction of rotation, the leading edge 23 is in front of the trailing edge 24, and the trailing edge 24 is behind the leading edge 23. The two ends of the blade root 21 may be connected to the inner ends of the leading edge 23 and the trailing edge 24, respectively. The two ends of the blade tip 22 may be connected to the outermost ends of the leading edge 23 and the trailing edge 24, respectively.

[0052] like Figure 3 As shown, in some embodiments, in the axial side view of the axial fan 100, the blade roots 21 of a plurality of blades 2 may be located on the outer peripheral wall of the hub 1, and the blade roots 21 of a plurality of blades 2 are located on the same circumference.

[0053] In some embodiments, in an axial side view of the axial fan 100, the tips 22 of the plurality of blades 2 may be located on the outermost side of the fan, and the tips 22 of the plurality of blades 2 may be located on another circumference.

[0054] like Figure 1 and Figure 2 As shown, in some embodiments, the blade 2 has a pressure surface 201 and a suction surface 202, which are located on opposite sides of the blade 2. The pressure surface 201 is typically the front side of the blade 2, and can also be called a positive pressure surface. The suction surface 202 is typically the back side of the blade 2, and can also be called a negative pressure surface. Taking the airflow direction M when the axial fan 100 rotates as a reference, the pressure surface 201 is located downstream of the suction surface 202. The suction surface 202 is located upstream of the pressure surface 201.

[0055] Figure 4 yes Figure 3 A magnified view of the local structure.

[0056] like Figure 3 and Figure 4 As shown, in some embodiments, a notch 241 extending towards the leading edge 23 may be provided at the trailing edge 24. The notch 241 design of the trailing edge 24 effectively disrupts the continuous structure of the trailing edge 24 of the blade 2, interfering with and reducing the periodic vortex shedding (Karman vortex street phenomenon) at the trailing edge 24, thereby achieving vortex suppression and reducing high-frequency noise. The notch 241 can disrupt the airflow separation point near the trailing edge 24 of the blade 2, making airflow separation smoother and more dispersed, reducing the generation of large-scale vortices, and thus improving the stability of airflow. When the smooth trailing edge 24 of the blade 2 rotates at high speed, the airflow shedding at the trailing edge 24 will generate periodic, high-intensity vortex shedding noise, manifested as a noticeable whistling sound and / or buzzing sound. The notch 241 design can effectively disrupt, disperse, and weaken the formation and intensity of this periodic vortex noise.

[0057] The related smooth trailing edge 24 structure design results in a relatively fixed airflow separation point, leading to relatively uniform and high-intensity vortex sizes and shedding frequencies, concentrated at specific frequencies. The notch 241 design of the trailing edge 24 disrupts the periodicity of the vortices, promotes small-scale turbulence, and alters the spectral characteristics of the sound source. Specifically, the presence of the notch 241 causes slight variations in the airflow separation point at different locations on the trailing edge 24, resulting in vortex sizes of varying sizes, asynchronous shedding times, and phase differences at different locations. This effectively disperses the strong noise energy originally concentrated at a certain frequency across a wider frequency range and reduces the peak sound pressure level at each frequency point, thus dispersing the energy. The edge of the notch 241 induces numerous smaller-scale turbulent vortices. These smaller vortices have lower energy, producing higher-frequency noise that is relatively less sensitive to the human ear and dissipates more quickly in the air. The final effect is to transform the originally prominent narrow-frequency discrete tone into a relatively smooth, broadband noise that is more easily masked by ambient background noise. The human ear is generally more comfortable to perceive broadband noise than narrow-frequency noise at the same sound pressure level.

[0058] like Figure 3 and Figure 4 As shown, in some embodiments, the sidewall of the notch 241 may include a first inclined wall 2411, which is disposed on the side of the notch 241 near the leaf root 21. The first inclined wall 2411 may extend toward the leaf root 21. The end of the first inclined wall 2411 near the leaf root 21 may be smoothly connected to the inner end of the trailing edge 24.

[0059] In some embodiments, the sidewall of the notch 241 may include a second inclined wall 2412, which is disposed on the side of the notch 241 near the blade tip 22. The first inclined wall 2411 and the second inclined wall 2412 are disposed on opposite sides of the notch 241. The second inclined wall 2412 may extend toward the blade tip 22. The end of the second inclined wall 2412 near the blade tip 22 may smoothly transition to the outer end of the trailing edge 24. The connection between the outer end of the trailing edge 24 and the end of the blade tip 22 may be an arc-shaped structure, so that the outer end of the trailing edge 24 smoothly transitions to the end of the blade tip 22.

[0060] like Figure 4 As shown, in some embodiments, the included angle between the first inclined wall 2411 and the second inclined wall 2412 is the axial expansion angle α, which is ≥67.7°. By setting the axial expansion angle α ≥67.7°, the notch 241 at the trailing edge 24 is sufficiently large, effectively disrupting the periodic shedding of the eddy current and dispersing and reducing eddy current noise. If the axial expansion angle α is less than 67.7°, the noise reduction effect is weak, failing to effectively disrupt the periodic shedding of the eddy current, and its effect on noise dispersion and reduction is limited, thus failing to achieve the expected noise reduction target.

[0061] In some embodiments, the axial expansion angle α ≤ 71.7°. By setting the axial expansion angle α ≤ 71.7°, the range of the notch 241 at the trailing edge 24 can be avoided from being too large, as an excessively large notch 241 can easily generate additional noise. An excessively large notch 241 will create strong local airflow separation and turbulence, which may itself become a new and significant broadband noise source, and may even generate new and undesirable discrete tone noise (such as whistling).

[0062] In some embodiments, the axial unfolding angle α can be in the range of 67.7°-71.7°. By setting the axial unfolding angle to 67.7°≤α≤71.7°, the range of the notch 241 at the trailing edge 24 can be made sufficiently large, while avoiding the notch 241 at the trailing edge 24 being too large, thus ensuring the noise reduction effect on eddy current noise and achieving the expected noise reduction target.

[0063] Figure 5 yes Figure 4 Another structural diagram.

[0064] like Figure 4 and Figure 5As shown, in some embodiments, the sidewall of the notch 241 may include an arc-shaped wall 2413, located between the first inclined wall 2411 and the second inclined wall 2412. One end of the arc-shaped wall 2413 is connected to one end of the first inclined wall 2411, and the other end of the arc-shaped wall 2413 is connected to one end of the second inclined wall 2412. Thus, the notch 241 can be formed by sequentially connecting the first inclined wall 2411, the arc-shaped wall 2413, and the second inclined wall 2412, allowing the first inclined wall 2411 and the second inclined wall 2412 to smoothly connect via the arc-shaped wall 2413, effectively disrupting the periodic shedding of the eddy current and ensuring noise reduction of the eddy current.

[0065] In some embodiments, the arc-shaped wall 2413 may have an arc structure. The center O of the arc-shaped wall 2413 is located inside the notch 241, so that the first inclined wall 2411 and the second inclined wall 2412 can be arranged to extend along the tangent directions on both sides of the arc-shaped wall 2413, respectively.

[0066] In some embodiments, the first inclined wall 2411 and the trailing edge 24 can be smoothly connected, and the second inclined wall 2412 and the trailing edge 24 can be smoothly connected.

[0067] like Figure 5 As shown, in some embodiments, the connection point between the leaf root 21 and the inner end of the trailing edge 24 is point A. The outer end of the trailing edge 24 and the leaf tip 22 form an arc structure. The tangent between point A and the outer end of the trailing edge 24 is at point B. A perpendicular line is drawn from the notch 241 relative to the connection between A and B. The point where the perpendicular line is at its maximum distance is the deepest point of the notch 241 in the trailing edge 24.

[0068] like Figure 5 As shown, in some embodiments, the chord length C1 corresponding to the blade tip 22 and the chord length C2 corresponding to the deepest point P of the notch 241 are given. The ratio of the chord length C2 corresponding to the deepest point P of the notch 241 to the chord length C1 corresponding to the blade tip 22 is C2 / C1≤0.56. By setting C2 / C1≤0.56, it can be ensured that the notch 241 has sufficient depth, thereby avoiding the notch 241 being too small. A notch 241 that is too small has a weak noise reduction effect, cannot effectively disrupt the periodic shedding of the eddy current, and has limited effect on noise dispersion and attenuation, failing to achieve the expected noise reduction target.

[0069] In some embodiments, the ratio of the chord length C2 corresponding to the deepest point P of the notch 241 to the chord length C1 corresponding to the blade tip 22 is C2 / C1≥0.52. By setting C2 / C1≥0.52, the depth of the notch 241 can be avoided, thus preventing the notch 241 from being too large. An excessively large notch 241 will disrupt the aerodynamic shape of the blade 2, significantly increase the aerodynamic drag of the blade 2, leading to decreased fan efficiency, increased energy consumption, and the possibility that the airflow / pressure may not meet design requirements. An excessively large notch 241 will also weaken the structural strength of the blade 2, and under high-speed rotation and alternating loads, it may increase stress concentration at the root of the blade 2 and at the notch 241, leading to an increased risk of fatigue fracture.

[0070] In some embodiments, the ratio of the chord length C2 corresponding to the deepest point P of the notch 241 to the chord length C1 corresponding to the tip 22 is in the range of 0.52-0.56, i.e., 0.52≤C2 / C1≤0.56. By setting 0.52≤C2 / C1≤0.56, it is possible to ensure that the notch 241 has sufficient depth while avoiding excessive depth, thereby enabling the notch 241 to effectively disrupt the formation of vortices at the trailing edge 24 and improve the airflow field; while ensuring the fan airflow, it effectively reduces the fan power and noise.

[0071] Figure 6 yes Figure 4 Another structural diagram.

[0072] like Figure 6 As shown, in some embodiments, the radius of the hub 1 is R0, the radius corresponding to the blade tip 22 is R1, and the radius corresponding to the deepest point P of the notch 241 is R2. Then, the distance L1 between the blade tip 22 and the hub 1 is L1 = (R1 - R0), and the distance L2 between the deepest point P of the notch 241 and the hub 1 is L2 = (R2 - R0). The ratio of the distance L2 between the deepest point of the notch 241 and the hub 1 to the distance L1 between the blade tip 22 and the hub 1 is L2 / L1 ≤ 0.67. By setting L2 / L1 ≤ 0.67, the notch 241 can maintain a certain distance from the blade tip 22, avoiding an excessively small distance between them. This prevents the airflow stability near the blade tip 22 on the trailing edge 24 from deteriorating, causing turbulent transitions at the trailing edge 24 and negatively impacting the overall smooth stability of the blade 2.

[0073] In some embodiments, the ratio of the distance L2 between the deepest part of the notch 241 and the hub 1 to the distance L1 between the blade tip 22 and the hub 1 is L2 / L1≥0.63. By setting L2 / L1≥0.63, the notch 241 can maintain a certain distance from the blade root 21, avoiding the situation where the distance between the notch 241 and the blade root 21 and the hub 1 is too small, resulting in a low airflow velocity near the hub 1, which would fail to achieve the effects of noise reduction and power reduction.

[0074] In some embodiments, the ratio of the distance L2 between the deepest part of the notch 241 and the hub 1 to the distance L1 between the blade tip 22 and the hub 1 ranges from 0.63 to 0.67, i.e., 0.63 ≤ L2 / L1 ≤ 0.67. By setting 0.63 ≤ L2 / L1 ≤ 0.67, the notch 241 can be close to the blade tip 22 while maintaining a certain distance from it, and also away from the blade root 21 and the hub 1. This effectively disrupts the formation of vortices at the trailing edge 24, improves the airflow field, and reduces the fan's power and noise.

[0075] Figure 7 yes Figure 2 The front view. Figure 8 yes Figure 7 A magnified view of the local structure.

[0076] like Figure 7 and Figure 8 As shown, in some embodiments, a first thickened area 25 may be provided on the suction surface 202 of the blade 2. The first thickened area 25 is located on the periphery of the notch 241 and in the connection area between the trailing edge 24 and the blade tip 22. The first thickened area 25 may be arc-shaped and protrude towards the leading edge 23, forming an arc-shaped edge 251. The first thickened area 25 can enhance the structural strength at the notch 241 and the structural strength of the connection area between the trailing edge 24 and the blade tip 22, which helps to reduce stress concentration, enhance the local strength of the blade 2, and avoid fatigue failure caused by long-term operation and stress concentration failure caused by drops during transportation. By thickening the notch 241 at the trailing edge 24, vortex shedding control can be achieved, broadband noise suppression can be achieved, and high-frequency vortex shedding noise can be weakened.

[0077] like Figure 8 As shown, in some embodiments, one end of the arcuate edge 251 of the first thickened region 25 connects to the blade tip 22 at point D. The other end of the arcuate edge 251 of the first thickened region 25 connects to the notch 241 of the trailing edge 24 at point E. The center of the arcuate edge 251 is O, and the angle between the line OD connecting the center of the arcuate edge 251 to one end of the arcuate edge 251 of the first thickened region 25 and the line OE connecting the center of the arcuate edge 251 to the other end of the arcuate edge 251 of the first thickened region 25 is the circumferential unfolding angle β, which is ≥157°. By setting the circumferential unfolding angle β≥157°, the range of the arcuate edge 251 of the first thickened region 25 can be made large enough to surround the peripheral area of ​​the notch 241, ensuring the thickening effect on the area of ​​the notch 241. If the circumferential unfolding angle β is too small, it will not be able to enclose the area of ​​gap 241 and will not be able to strengthen the gap 241.

[0078] like Figure 8As shown, in some embodiments, the circumferential unfolding angle β between the line OD connecting the center of the arcuate edge 251 to one end of the arcuate edge 251 of the first thickened area 25 and the line OE connecting the center of the arcuate edge 251 to the other end of the arcuate edge 251 of the first thickened area 25 satisfies the condition that the circumferential unfolding angle β ≤ 163°. By setting the circumferential unfolding angle β ≤ 163°, the range of the arcuate edge 251 of the first thickened area 25 can be avoided from being too large, as an excessively large arcuate edge 251 of the first thickened area 25 can easily increase costs.

[0079] like Figure 8 As shown, in some embodiments, the circumferential expansion angle β between the line OD connecting the center of the arc-shaped edge 251 to one end of the arc-shaped edge 251 of the first thickened area 25 and the line OE connecting the center of the arc-shaped edge 251 to the other end of the arc-shaped edge 251 of the first thickened area 25 satisfies the condition that the circumferential expansion angle β ranges from 157° to 163°, i.e., 157° ≤ β ≤ 163°. By limiting the circumferential expansion angle β to 157°-163°, it is possible to ensure that the arc-shaped edge 251 of the first thickened area 25 is large enough to surround the peripheral area of ​​the notch 241, thus ensuring the thickening effect on the notch 241 area, while also preventing the arc-shaped edge 251 of the first thickened area 25 from becoming too large, thereby reducing costs.

[0080] Figure 9 yes Figure 8 Another structural diagram.

[0081] like Figure 9 As shown, in some embodiments, the radius of the hub 1 is R0, the radius corresponding to the blade tip 22 is R1, and the radius of the position of the first thickened area 25 near the blade root 21 is R3. Then, the distance L3 between the end of the first thickened area 25 near the blade root 21 and the hub 1 is L3 = R3 - R0, and the distance L1 between the blade tip 22 and the hub 1 is L1 = R1 - R0. Therefore, the ratio L3 / L1 ≥ 0.42 is the same as the distance L3 between the end of the first thickened area 25 near the blade root 21 and the hub 1. By setting L3 / L1 ≥ 0.42, the radial position range of the first thickened area 25 can be avoided from being too large, thereby avoiding increased costs.

[0082] In some embodiments, the ratio L3 / L1 of the distance L3 between the end of the first thickened region 25 near the blade root 21 and the hub 1 and the distance L1 between the blade tip 22 and the hub 1 is ≤0.46. By setting L3 / L1≤0.46, the range of the first thickened region 25 can be avoided from being too small, ensuring that the range of the first thickened region 25 is large enough to surround the peripheral area of ​​the notch 241 and ensure the thickening effect on the area of ​​the notch 241.

[0083] In some embodiments, the ratio L3 / L1, which is the distance L3 between the end of the first thickened region 25 near the blade root 21 and the hub 1 and the distance L1 between the blade tip 22 and the hub 1, ranges from 0.42 to 0.46. This L3 / L1 ratio range of 0.42-0.46 ensures that the first thickened region 25 is sufficiently large to surround the peripheral area of ​​the notch 241, thus ensuring a thickening effect on the notch 241 area. It also avoids the first thickened region 25 having an excessively large radial position, thereby preventing increased costs.

[0084] Figure 10 yes Figure 8 Another structural diagram.

[0085] like Figure 7 and Figure 10 As shown, in some embodiments, a second thickened region 26 may be provided on the suction surface 202 of the blade 2. The second thickened region 26 is arranged along the edge of the leading edge 23, one end of the second thickened region 26 is connected to the blade root 21, and the other end of the second thickened region 26 is spaced apart from the blade tip 22. The second thickened region 26 can enhance the structural strength at the leading edge 23, which helps to reduce stress concentration, enhance the local strength of the blade 2, and avoid fatigue failure caused by long-term operation and stress concentration failure caused by drops during transportation. By thickening the leading edge 23, the local structural strength of the blade 2 can be improved, and flow separation can be delayed.

[0086] like Figure 10 As shown, in some embodiments, the chord length of the region connecting the second thickened region 26 and the leaf root 21 is C3, and the chord length of the leaf root 21 is C4. The ratio of C3 to C4 satisfies C3 / C4 ≥ 0.18. By setting C3 / C4 ≥ 0.18, the second thickened region 26 has sufficient width to ensure that the structural strength at the leading edge 23 is enhanced. If the width of the second thickened region 26 is too small, its strength-enhancing effect on the leading edge 23 will be minimal, failing to provide an effective strength enhancement.

[0087] In some embodiments, the ratio of the chord length C3 of the region where the second thickened region 26 is connected to the leaf root 21 to the chord length C4 of the leaf root 21 satisfies C3 / C4≤0.22. By setting C3 / C4≤0.22, the width of the second thickened region 26 can be avoided from being too large, which would increase the cost.

[0088] In some embodiments, the ratio of the chord length C3 of the region where the second thickened region 26 is connected to the leaf root 21 to the chord length C4 of the leaf root 21 ranges from 0.18 to 0.22, i.e., 0.18 ≤ C3 / C4 ≤ 0.22. By setting 0.18 ≤ C3 / C4 ≤ 0.22, the second thickened region 26 can have sufficient width to ensure that the structural strength at the leading edge 23 is enhanced; at the same time, the width of the second thickened region 26 can be avoided to prevent it from being too large and thus avoid increasing costs.

[0089] Figure 11 yes Figure 1 Side view.

[0090] like Figure 1 and Figure 10 As shown, in some embodiments, the blade tip 22 is bent towards the pressure surface 201 to form a flange 27. The flange 27 can help increase the air volume, thereby reducing power and noise while maintaining the same air volume.

[0091] In some embodiments, this application also provides an air conditioner including an outdoor unit, which houses an outdoor heat exchanger and an axial fan 100. The axial fan 100 is the axial fan 100 described in the above embodiments. The axial fan 100 is used to dissipate heat from the outdoor heat exchanger. The rotation of the axial fan 100 generates directional airflow to pass through the outdoor heat exchanger, whereby the air exchanges heat with the heat exchanger to dissipate heat from the outdoor heat exchanger.

[0092] Although the present invention has been described with reference to several typical embodiments, it should be understood that the terminology used is descriptive and exemplary, and not restrictive. Since the present invention can be embodied in many forms without departing from the spirit or essence of the invention, it should be understood that the above embodiments are not limited to any of the foregoing details, but should be interpreted broadly within the spirit and scope defined by the appended claims. Therefore, all variations and modifications falling within the scope of the claims or their equivalents should be covered by the appended claims.

Claims

1. An axial flow fan, characterized in that, include: Wheel hub; Multiple blades are spaced apart along the circumferential direction on the outer peripheral wall of the hub, the blades comprising: Leaf roots are formed at the edge of the blade that connects to the hub; The blade tip is formed at the edge of the blade away from the hub; Leading edge, formed at the windward edge of the blade in the direction of rotation; The trailing edge is formed at the edge of the leeward end in the direction of rotation of the blade; the trailing edge has a notch extending toward the leading edge. The sidewall of the notch includes: A first inclined wall is provided on the side of the notch closer to the leaf root; A second inclined wall is provided on the side of the notch near the tip of the blade; The first inclined wall and the second inclined wall are located on opposite sides of the notch, and the included angle between the first inclined wall and the second inclined wall is the axial expansion angle, which ranges from 67.7° to 71.7°.

2. The axial flow fan as described in claim 1, characterized in that, The ratio of the chord length corresponding to the deepest part of the notch to the chord length corresponding to the tip of the leaf ranges from 0.52 to 0.

56.

3. The axial flow fan as described in claim 1, characterized in that, The radius of the hub is R0, the radius of the blade tip is R1, and the radius of the deepest part of the notch is R2. The ratio of the distance R2-R0 between the deepest part of the notch and the hub to the distance R1-R0 between the blade tip and the hub is in the range of 0.63-0.

67.

4. The axial flow fan as described in claim 1, characterized in that, The sidewall of the notch includes: An arc-shaped wall is located between the first inclined wall and the second inclined wall; One end of the arc-shaped wall is connected to the first inclined wall, and the other end is connected to the second inclined wall; the deepest part of the notch is located on the arc-shaped wall.

5. The axial flow fan as described in claim 4, characterized in that, The blade has a first thickened area on its suction surface. The first thickened area is located around the notch and in the connection area between the trailing edge and the blade tip. The first thickened area has an arc-shaped protrusion along one side of the leading edge.

6. The axial flow fan as described in claim 5, characterized in that, The angle between the line connecting one end of the arc-shaped edge of the first thickened area to the center of the arc-shaped wall and the line connecting the other end of the arc-shaped edge of the first thickened area to the center of the arc-shaped wall is the circumferential unfolding angle, and the circumferential unfolding angle ranges from 157° to 163°.

7. The axial flow fan as described in claim 5, characterized in that, The radius of the first thickened area near the end of the leaf root is R3; The radius of the blade tip is R1, and the radius of the hub is R0; The ratio of the distance R3-R0 between the end of the first thickened area near the blade root and the hub to the distance R1-R0 between the blade tip and the hub is in the range of 0.42-0.

46.

8. The axial flow fan as described in claim 1, characterized in that, The blade has a second thickened area on its suction surface. The second thickened area is arranged along the edge of the leading edge. One end of the second thickened area is connected to the leaf root, and the other end of the second thickened area is spaced apart from the leaf tip.

9. The axial flow fan as described in claim 8, characterized in that, The ratio of the chord length of the second thickened area connected to the leaf root to the chord length of the leaf root ranges from 0.18 to 0.

22.

10. An air conditioner, characterized in that, An axial fan comprising any one of claims 1-9.

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