Axial flow fan blade, axial flow fan and air conditioning equipment

Abstract

The present application relates to the technical field of air conditioning equipment, and in particular, to an axial flow fan, an axial flow fan and an air conditioning equipment. The axial flow fan includes a hub rotating around a central axis and blades extending radially outward from the hub and arranged around the central axis. A guide surface is formed on the side of the hub between the suction surface of the first blade and the pressure surface of the second blade adjacent to the first blade. The guide surface is a curved surface surrounded by a first curve AB, a second curve BC, a third curve CD and a fourth curve DA. The second curve BC is located on the front end surface of the hub, the fourth curve DA is close to the inner edge of the first blade, the endpoints A and B are located in front of the front end point of the inner edge of the first blade, and the endpoints C and D are located at the rear of the front end point of the inner edge of the first blade and in front of the front end point of the inner edge of the second blade. The axial flow fan blade is applied to the axial flow fan, which improves the fan efficiency and reduces turbulence and aerodynamic noise.

Description

Technical Field

[0001] The present application relates to the technical field of air conditioning equipment, and in particular to an axial flow fan blade, and also to an axial flow fan and air conditioning equipment including the axial flow fan blade. Background Art

[0002] Axial flow fans are widely used in air conditioning products due to their large air volume and low noise. The efficiency of axial flow fans and air ducts in air conditioners has an important impact on the air conditioning capacity, energy efficiency and comfort. Low air volume of the fan blades will cause poor heat exchange on the air conditioner heat exchanger side, resulting in low air conditioning capacity and increased system power on the refrigerant side; at the same time, low fan efficiency will result in high fan input power. Therefore, the air volume and efficiency of axial flow fans and air ducts in air conditioners have a significant impact on the performance of air conditioners.

[0003] The existing axial flow fan blades have low efficiency and high aerodynamic noise when working. Summary of the invention

[0004] The technical problem to be solved by the embodiments of the present invention is that the existing axial flow fan blades have low efficiency and high aerodynamic noise when working. In order to solve the above technical problems, the present application provides an axial flow fan blade, an axial flow fan including the axial flow fan blade, and an air conditioning device, so as to improve the aerodynamic characteristics of the axial flow fan blade, improve working efficiency, reduce aerodynamic noise, and provide comfort for air conditioning use.

[0005] In order to achieve the above objective, according to one aspect of the present technical solution, an embodiment of the present invention provides an axial flow fan blade.

[0006] According to an embodiment of the present invention, an axial flow fan blade includes a hub rotating around a central axis and blades extending radially outward from the hub and arranged around the central axis, the inner edge of the blade is connected to the side of the hub, each of the blades has a suction surface and a pressure surface, the extension direction of the central axis is defined as a front-to-back direction, a guide surface is formed on the side of the hub between the suction surface of the first blade and the pressure surface of the second blade adjacent to the first blade, the guide surface is a curved surface surrounded by a first curve AB, a second curve BC, a third curve CD and a fourth curve DA, the second curve BC is located on the front end surface of the hub, the fourth curve DA is close to the inner edge of the first blade, endpoints A and B are located in front of the front end point of the inner edge of the first blade, endpoints C and D are located in the rear of the rear end point of the inner edge of the first blade and in front of the front end point of the inner edge of the second blade.

[0007] Furthermore, in a cross section of the axis passing through the central axis, an angle θ is included between a tangent line at the end point of the guide surface away from the central axis and a tangent line at the suction surface of the blade connected to the hub. Angle θ is located between the blade and the hub, and θ gradually increases along the rotation direction of the axial flow fan blade.

[0008] Furthermore, in a cross section passing through the axis of the central axis, the curvature of the guide surface gradually decreases along the rotation direction of the axial flow fan blade.

[0009] Furthermore, the projection of the second curve BC in a plane perpendicular to the central axis is a curve B1C1, and any point on the curve B1C1 is located on the first equation curve, and the first equation curve is given by the parametric equation

[0010] x=(R c +λ)t-(R c +λ)*sin(t)-R b and

[0011] y=(R c +λ)-(R c +λ)*cos(t)

[0012] Determined, where R b is the distance from B to the center axis, R c is the distance from C to the central axis, λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

[0013] Furthermore, the projection of the second curve BC in a plane perpendicular to the central axis is a curve B1C1, and any point on the curve B1C1 is located on the second equation curve, and the second equation curve is given by the parametric equation

[0014] x=2R b *sin(t)+R b and

[0015] y=(R c +λ)*cos(t)

[0016] Determined, where R b is the distance from B to the center axis, R c is the distance from C to the central axis, λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

[0017] Furthermore, at least one reinforcing rib is provided on the wheel hub.

[0018] Furthermore, at least two blades are provided.

[0019] Furthermore, the edges of the guide surface are transitioned by rounding.

[0020] In order to achieve the above-mentioned purpose, according to the second aspect of the present technical solution, the present technical solution also provides an axial flow fan.

[0021] According to the axial flow fan of the embodiment of the present application, it includes the axial flow fan blade provided by the first aspect of the present invention.

[0022] In order to achieve the above-mentioned purpose, according to the third aspect of the present technical solution, the present technical solution also provides an air conditioning device.

[0023] The air conditioning equipment according to the embodiment of the present application includes the axial flow fan provided by the second aspect of the present invention.

[0024] The axial flow blades provided in the above technical solution are applied to axial flow fans or air conditioners, which improves the structural characteristics of the axial flow blades, makes the air intake of the flow channel smoother, improves the fan efficiency, solves the problem of low energy efficiency caused by poor heat exchange of the air conditioner, reduces turbulence, and reduces the aerodynamic noise of the blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The drawings constituting a part of this application are used to provide a further understanding of this application, so that other features, purposes and advantages of this application become more obvious. The schematic embodiment drawings and their descriptions of this application are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0026] Figure 1 A three-dimensional diagram of an axial flow fan blade provided in an embodiment of the present application;

[0027] Figure 2 A front view of an axial flow fan blade provided in an embodiment of the present application;

[0028] Figure 3 A side view of an axial flow fan blade provided in an embodiment of the present application;

[0029] Figure 4 A rear view of an axial flow fan blade provided in an embodiment of the present application;

[0030] Figure 5 The orthographic projection of the axial flow fan blade provided in the embodiment of the present application Figure 1 ;

[0031] Figure 6 The orthographic projection of the axial flow fan blade provided in the embodiment of the present application Figure 2 ;

[0032] Figure 7 A front view of an axial flow fan blade provided in an embodiment of the present application;

[0033] Figure 8 for Figure 7 MM cross-section diagram in;

[0034] Fig. 9 for Figure 7 LL cross-section diagram in;

[0035] Fig.10 for Figure 7 NN cross-section diagram in;

[0036] Fig.11 A three-dimensional diagram of an axial flow fan blade provided in an embodiment of the present application;

[0037] Fig.12 A power data comparison curve of the axial flow fan blades in the embodiment of the present application and the comparative example;

[0038] Fig.13 It is a noise data comparison curve of the axial flow fan blades in the embodiment of the present application and the comparative example.

[0039] In the figure:

[0040] 1. Hub; 101. Shaft hole; 102. Front end face; 103. Rear end face; 104. Guide surface; 105. Reinforcing rib; 106. Chamfered corner; 2. Blades; 2-1. First blade; 2-2. Second blade; 201. Leading edge; 202. Outer edge; 203. Trailing edge; 204. Inner edge; 205. Suction surface; 206. Pressure surface. DETAILED DESCRIPTION

[0041] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0042] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a system, product or device comprising a series of units is not necessarily limited to those units explicitly listed, but may include units that are not explicitly listed or inherent to these products or devices.

[0043] In this application, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "middle", "outer", etc. are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0044] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0045] In addition, the terms "disposed", "connected", and "fixed" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application may be combined with each other.

[0047] like Figure 1-4 As shown, the axial flow fan blade according to the embodiment of the present invention includes a hub 1 and blades 2 .

[0048] The hub 1 is a columnar or column-like structure, and a shaft hole 101 is provided in the center thereof for the central axis to pass through. The extension direction of the central axis is defined as the front-to-back direction, and the specific direction indication is shown by the arrow in the figure. The hub 1 includes a front face 102, a rear face 103 and a side face, and can rotate around the central axis. The blades 2 extend radially outward from the hub 1 and are arranged around the central axis. The blades 2 are curved panels formed by four curves, namely, a leading edge 201, an outer edge 202, a trailing edge 203 and an inner edge, and the blades 2 are connected to the side face of the hub 1 through an inner edge 204. Each blade 2 includes a suction surface 205 and a pressure surface 206. The suction surface 205 of each blade 2 forms an airflow channel of the axial flow blade with the pressure surface 206 of the next blade 2 and the side face of the hub 1.

[0049] For the convenience of description, Figure 1As shown, two adjacent blades 2 on the hub 1 are taken as an example for explanation, wherein one blade 2 is a first blade 21, and the other adjacent blade 2 is a second blade 22. An air flow channel of the axial flow blade is formed between the suction surface 205 of the first blade 21, the pressure surface 206 of the second blade 22 and the side surface of the hub 1, and a guide surface 104 is formed on the side surface of the hub 1 between the suction surface 205 of the first blade 21 and the pressure surface 206 of the second blade 22, that is, the guide surface 104 is located between the first blade 21 and the second blade 22 and is formed on the side surface of the hub 1. The guide surface 104 is a curved surface surrounded by a first curve AB, a second curve BC, a third curve CD and a fourth curve DA, wherein the second curve BC is located on the front end surface 102 of the hub 1, the fourth curve DA is close to the inner edge of the first blade 21, the endpoints of the second curve BC are B and C, the endpoints of the fourth curve DA are A and D, the front endpoint of the inner edge of the first blade 21 is E, the rear endpoint of the inner edge of the first blade 21 is F, and the front endpoint of the inner edge of the second blade 22 is G. In the embodiment of the present invention, endpoints A and B are located in front of the front end point E of the inner edge of the first blade 21, and endpoints C and D are located in the rear of the rear endpoint F of the inner edge of the first blade 21 and in front of the front end point G of the inner edge of the second blade 22. When the axial flow fan blades with the above structural design are working, the inner edge of the suction surface 205 of the first blade 21 is at low pressure, so that the gas is gradually accelerated along the axial direction of the axial flow fan on the outer side of the hub 1. Therefore, the guide surface range is set to include the inner edge of the first blade, so that the airflow starts to be guided at the front section of the air blade flow channel to reduce the air intake loss.

[0050] The first curve AB, the third curve CD and the fourth curve DA can be set as a straight line or a non-straight line. For example, as shown in the drawings of the present application, the first curve AB and the third curve CD can be set as a straight line, and the fourth curve DA is a non-straight line set along the inner edge of the first blade.

[0051] like Figure 5 and 6 As shown, the projection of the second curve BC in the plane perpendicular to the central axis is curve B1C1, and a plane rectangular coordinate system is established in the projection plane, wherein the coordinate origin O is located on the axis of the central axis, the positive direction of the X-axis is from B1 to O, and the X-axis is rotated 90° along the rotation direction of the axial flow fan blade in the coordinate system plane to obtain the Y-axis.

[0052] As an optional implementation, Figure 5 As shown, based on the above rectangular coordinate system, any point on the curve B1C1 is located on the first equation curve, and the first equation curve is determined by the parameter equation (I), and the parameter equation (I) is

[0053] x=(R c +λ)t-(Rc +λ)*sin(t)-R b and

[0054] y=(R c +λ)-(R c +λ)*cos(t)

[0055] Among them, R b is the distance from B to the center axis, in mm; R c is the distance from C to the center axis, in mm; λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

[0056] As an optional implementation, Figure 6 As shown, based on the above rectangular coordinate system, the projection of the second curve BC in the plane perpendicular to the central axis is a curve B1C1, and any point on the curve B1C1 is located on the second equation curve, and the second equation curve is determined by the parametric equation (II), and the parametric equation (II) is

[0057] x=2R b *sin(t)+R b and

[0058] y=(R c +λ)*cos(t)

[0059] Among them, R b is the distance from B to the center axis, in mm; R c is the distance from C to the center axis, in mm; λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

[0060] In the above embodiment, if Figure 7-10 As shown, in the cross section of the axis through the central axis, the angle between the tangent of the guide surface 104 at the end point away from the central axis and the tangent of the suction surface 205 of the blade 2 connecting to the hub 1 is θ, and the angle θ is located between the blade and the hub, and θ gradually increases along the rotation direction of the axial flow fan blade. Specifically in the accompanying drawings, the rotation direction of the axial flow fan blade is counterclockwise, and along the rotation direction, the values ​​of θ are θ3, θ2 and θ1, respectively, and θ1≥θ2≥θ3 is satisfied.

[0061] In the above embodiment, the guide surface 104 in the embodiment of the present invention is designed to be in a variable curvature form, and in the cross section of the axis through the central axis, the curvature of the guide surface 104 gradually decreases along the rotation direction of the axial flow fan blade. Specifically in the figure, the rotation direction of the axial flow fan blade is counterclockwise, and along the rotation direction, the curvature of the guide surface 104 in the cross section takes the values ​​of ρ3, ρ2 and ρ1 in sequence, and ρ1≤ρ2≤ρ3 is satisfied.

[0062] By setting the angle θ and the curvature of the guide surface 104, the specific convex curved surface structure of the guide surface is more conducive to guiding the gas during the rotation of the axial flow fan blade, thereby reducing the fan power and noise.

[0063] In order to enhance the strength of the wheel hub 1 , at least one reinforcing rib 105 is disposed on the wheel hub 1 . The reinforcing rib 105 can be designed to be spoke-shaped or circular as required.

[0064] The axial flow fan blade provided in the embodiment of the present invention has at least two blades 2, and may also have more blades. Preferably, the blades 2 are evenly arranged circumferentially on the hub 1. Of course, the angles between the blades 2 may be changed according to actual requirements, so that the blades 2 are unevenly arranged on the hub 1. Fig.11 As shown, the edges of the guide surface 104 are transitioned through rounded corners 106. This can reduce stress concentration at the edges, extend the service life, and prevent sharp edges from cutting people or objects during storage and transportation.

[0065] Example 1

[0066] An axial flow fan blade includes a hub 1 and blades 2. The hub 1 is provided with an axial hole 101 for the central axis to pass through at its center. The hub 1 includes a front face 102, a rear face 103 and a side face, and can rotate around the central axis. The blades 2 extend radially outward from the hub 1 and are arranged around the central axis. The blades 2 are curved panels formed by four curves, namely, a leading edge 201, an outer edge 202, a trailing edge 203 and an inner edge. The blades 2 are connected to the side face of the hub 1 through an inner edge 204. Each blade 2 includes a suction face 205 and a pressure face 206. The suction face 205 of each blade 2, the pressure face 206 of the next blade 2 and the side face of the hub 1 form an airflow channel of the axial flow fan blade. Each axial flow fan blade is evenly provided with three blades 2. Two adjacent blades 2 on the hub 1 are taken as an example for explanation. One blade 2 is a first blade 21, and the other adjacent blade 2 is a second blade 22. An air flow channel of the axial flow fan blade is formed between the suction surface 205 of the first blade 21, the pressure surface 206 of the second blade 22 and the side of the hub 1. A guide surface 104 is formed on the side of the hub 1 between the suction surface 205 of the first blade 21 and the pressure surface 206 of the second blade 22, that is, the guide surface 104 is located between the first blade 21 and the second blade 22 and is formed on the side of the hub 1. The guide surface 104 is a curved surface surrounded by a first curve AB, a second curve BC, a third curve CD and a fourth curve DA. The first curve AB and the third curve CD can be set in a straight line form, and the fourth curve DA is a non-straight line set along the inner edge of the first blade. The second curve BC is located on the front end face 102 of the hub 1, the fourth curve DA is close to the inner edge of the first blade 21, the endpoints of the second curve BC are B and C, the endpoints of the fourth curve DA are A and D, the front endpoint of the inner edge of the first blade 21 is E, the rear endpoint of the inner edge of the first blade 21 is F, and the front endpoint of the inner edge of the second blade 22 is G. In the embodiment of the present invention, endpoints A and B are located in front of the front end point E of the inner edge of the first blade 21, and endpoints C and D are located in the rear of the rear endpoint F of the inner edge of the first blade 21 and in front of the front end point G of the inner edge of the second blade 22. In the cross section passing through the axis of the central axis, the angle between the tangent of the guide surface 104 at the endpoint away from the central axis and the tangent of the suction surface 205 of the blade 2 connecting to the hub 1 is θ, and θ gradually increases along the rotation direction of the axial flow fan blade. In the cross section passing through the axis of the central axis, the curvature of the guide surface 104 gradually decreases along the rotation direction of the axial flow fan blade.

[0067] According to Figure 5 As shown, the projection of the second curve BC in a plane perpendicular to the central axis is a curve B1C1, and any point on the curve B1C1 is located on the first equation curve, and the first equation curve is determined by the parametric equation (I), and the parametric equation (I) is

[0068] x=(R c +λ)t-(R c +λ)*sin(t)-R b and

[0069] y=(R c +λ)-(R c +λ)*cos(t),

[0070] Where R b =20mm, R c =48mm, λ=-10. That is, the parameter equation (I) is

[0071] x=38t-38sin(t)-20, y=38-38cos(t).

[0072] Example 2

[0073] The difference between an axial flow fan blade of this embodiment and embodiment 1 is that:

[0074] According to Figure 6 As shown, the projection of the second curve BC in the plane perpendicular to the central axis is a curve B1C1, and any point on the curve B1C1 is located on the first equation curve, and the first equation curve is determined by the parametric equation (II), and the parametric equation (II) is

[0075] x=2R b *sin(t)+R b and

[0076] y=(R c +λ)*cos(t),

[0077] Where R b =20mm, R c =48mm, λ=0, that is, the parameter equation (II) is

[0078] x=40sin(t)+20, y=48cos(t).

[0079] The other configurations of the axial flow fan blades are exactly the same as those in the first embodiment.

[0080] Comparative Example

[0081] This comparative example is used to achieve a comparison with the effects of the embodiments 1-2 of the present application. This comparative example uses an axial flow fan blade in the prior art. The difference between the axial flow fan blade and the embodiments 1-2 is that the hub is a cylindrical structure and no guide surface is set on the side. The other structural settings are the same as those of the embodiments 1-2.

[0082] The present application conducts tests and comparisons on the fans used for the axial flow fan blades provided in Examples 1-2 and Comparative Examples. The test data are shown in Tables 1-3 and Figure 12-13 .

[0083] Table 1 Comparative Example Test Data

[0084] Power(W) <![CDATA[Air volume (m 3 / h)]]> Speed ​​(rpm) Noise(dB) 48.2 1377 771.1 46.9 50.0 1461 815.3 47.2 51.2 1512 846.1 47.3 52.6 1551 868.6 47.4 54.1 1579 884.8 47.5 55.8 1602 897.6 47.6 57.7 1619 908.2 47.6 59.5 1635 916.6 47.6 61.0 1646 923 47.7

[0085] Table 2 Experimental data of Example 1

[0086] Power(W) <![CDATA[Air volume (m 3 / h)]]> Speed ​​(rpm) Noise(dB) 48.3 1389 768.7 46.8 50.2 1475 810.6 47.0 51.3 1539 842.2 47.2 53.0 1595 861.2 47.3 54.3 1629 879.5 47.4 56.1 1659 889.3 47.6 57.8 1685 899.2 47.7 59.6 1705 910.2 47.9 61.1 1719 916.3 48.1

[0087] Table 3 Axial flow fan blade test data of Example 2

[0088] Power(W) <![CDATA[Air volume (m 3 / h)]]> Speed ​​(rpm) Noise(dB) 48.6 1383 769.2 46.8 50.5 1471 811.1 47.1 51.5 1536 842.7 47.2 53.3 1591 861.7 47.4 54.6 1626 880 47.5 56.4 1656 889.8 47.6 58.1 1680 899.7 47.8 59.9 1701 910.7 47.9 61.4 1713 916.8 48.1

[0089] By comparing the experimental data of Examples 1 and 2 of the present application with the axial flow fan blades of the prior art, it can be clearly seen that when the axial flow fan blades of the present application are used, the fan power and fan noise are significantly reduced compared with the axial flow fan blades of the prior art under the same air volume conditions.

[0090] It should be noted that other structures and operations of the axial flow fan blades provided in the embodiments of the present invention are known to those skilled in the art and can refer to the structures of related devices in the prior art, and will not be described in detail here.

[0091] The embodiment of the present application also provides an axial flow fan and air conditioning equipment, wherein the axial flow fan includes the axial flow fan blades provided in the above embodiment of the present application, and the air conditioning equipment includes the axial flow fan. The air conditioning equipment includes but is not limited to an air conditioner, an air purifier, an air humidifier and an air exchanger.

[0092] Since the axial flow fan and air conditioning equipment disclosed in the embodiments of the present application include the axial flow fan blades provided in the above embodiments, the axial flow fan and air conditioning equipment having the axial flow fan blades also have all the above technical effects, which will not be described one by one here. Other structures and operations of the axial flow fan blades and air conditioning equipment are known to ordinary technicians in the field and will not be described in detail here.

[0093] Some embodiments in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the embodiments can be referenced to each other.

[0094] The foregoing is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features claimed herein.

Claims

1. An axial flow fan blade, comprising a hub rotating around a central axis and blades extending radially outward from the hub and arranged around the central axis, wherein the inner edges of the blades are connected to the side surfaces of the hub, each of the blades has a suction surface and a pressure surface, and the extension direction of the central axis is defined as a front-rear direction, characterized in that: A guide surface is formed on the side surface of the hub between the suction surface of the first blade and the pressure surface of the second blade adjacent to the first blade, and the guide surface is a curved surface surrounded by a first curve AB, a second curve BC, a third curve CD and a fourth curve DA, the second curve BC is located on the front end surface of the hub, the fourth curve DA is close to the inner edge of the first blade, endpoints A and B are located in front of the front end point of the inner edge of the first blade, endpoints C and D are located in the rear of the rear end point of the inner edge of the first blade and in front of the front end point of the inner edge of the second blade; in a cross section of the axis passing through the central axis, an angle θ is included between a tangent of the guide surface at the end point away from the central axis and a tangent of the suction surface of the blade connected to the hub, and the angle θ is located between the blade and the hub, and the angle gradually increases along the rotation direction of the axial flow fan blade.

2. The axial flow fan blade according to claim 1, characterized in that: In a cross section passing through the axis of the central axis, the curvature of the guide surface gradually decreases along the rotation direction of the axial flow fan blade.

3. The axial flow fan blade according to claim 1, characterized in that: The projection of the second curve BC in a plane perpendicular to the central axis is a curve B1C1. Any point on the curve B1C1 is located on the first equation curve. The first equation curve is given by the parametric equation x=(R c +λ)t-(R c +λ)*sin(t)-R b and y=(R c +λ)-(R c +λ)*cos(t) Determined, where R b is the distance from the end point B to the axis of the central axis, R c is the distance from the end point C to the axis of the central axis, λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

4. The axial flow fan blade according to claim 1, characterized in that: The projection of the second curve BC in a plane perpendicular to the central axis is a curve B1C1. Any point on the curve B1C1 is located on the second equation curve. The second equation curve is given by the parametric equation x=2R b *sin(t)+R b and y=(R c +λ)*cos(t) Determined, where R b is the distance from the end point B to the axis of the central axis, R c is the distance from the end point C to the axis of the central axis, λ is a constant and -R c ≤λ≤R c , t is a parameter and 0≤t≤2π.

5. The axial flow fan blade according to claim 1, characterized in that: At least one reinforcing rib is arranged on the wheel hub.

6. The axial flow fan blade according to claim 1, characterized in that: At least two blades are provided.

7. The axial flow fan blade according to claim 1, characterized in that: The edges of the flow guide surface are transitioned through rounded corners.

8. An axial flow fan, characterized in that: It comprises the axial flow fan blade as described in any one of claims 1 to 7.

9. An air conditioning device, characterized in that: Including the axial flow fan as described in claim 8.

Images