A middle section wind blade, a through-flow wind blade and an air conditioner

Abstract

The present application relates to air conditioning technical field, it relates to a middle section fan blade, cross flow fan blade and air conditioner, wherein, the middle section fan blade includes disc, the disc has opposite first side and second side, the first side is equipped with blade, the second side is equipped with the welding groove for welding with the blade on another middle section fan blade, the number of the welding groove is two or more, and sequentially interval arrangement along the circumference of disc;The second side is equipped with sound attenuation groove still, the sound attenuation groove is located between two welding grooves of adjacent. According to the technical scheme of the present application, airflow can flow through sound attenuation groove when cross flow fan blade rotates, the sound attenuation groove can change the frequency of airflow and the wall surface collision of disc, reduce the aerodynamic noise when cross flow fan blade rotates;In addition, the sound attenuation groove can form sound attenuation cavity structure and carry out sound attenuation treatment to the airflow passing through, so that the propagation of noise can be further reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the air conditioning technical field, in particular to a middle section fan blade, a cross-flow fan blade and an air conditioner. BACKGROUND

[0002] As shown in Figure 1 , the cross-flow fan blade includes a shaft cover 1, an end cover 3 and a plurality of middle section fan blades 2. As shown in Figure 2 , the middle section fan blade 2 includes a disc 21 and a blade 22 arranged on one side of the disc 21. The disc 21 is provided with a welding groove 211 on the side away from the blade 22, and the disc 21 is welded with the blade 22 of another middle section fan blade 2 through the welding groove 211. Wherein, the blade 22 is welded by manually rotating the middle section fan blade 2 to find the welding groove 211.

[0003] The above-mentioned cross-flow fan blade generates aerodynamic rotating noise in the process of rotating work due to the periodic impact of airflow and the surrounding solid wall surface, which includes the surface of the blade 22 and the disc 21 fixing the blade 22. The aerodynamic noise of the existing cross-flow fan blade is improved by changing the structure design of the blade surface. In the case that the existing blade structure mold is fixed, how to further improve the aerodynamic noise of the cross-flow fan blade has become a problem to be solved in the field. SUMMARY

[0004] Therefore, the present application provides a middle section fan blade, a cross-flow fan blade and an air conditioner, which mainly solves the technical problem of how to further reduce the aerodynamic noise of the cross-flow fan blade in rotation.

[0005] To achieve the above-mentioned purpose, the present application mainly provides the following technical scheme:

[0006] In a first aspect, the embodiments of the present application provide a middle section fan blade, which includes a disc, the disc has a first side and a second side opposite to each other, the first side is provided with a blade, and the second side is provided with a welding groove for welding with a blade on another middle section fan blade, the number of the welding groove is two or more, and the welding grooves are arranged in sequence and spaced along the circumference of the disc.

[0007] Wherein, the second side is further provided with a sound-absorbing groove, and the sound-absorbing groove is located between the two adjacent welding grooves.

[0008] In some embodiments, the number of the sound-absorbing grooves is two or more, and the sound-absorbing grooves are arranged in sequence and spaced along the circumference of the disc.

[0009] In the cross section perpendicular to the axial direction of the middle section fan blade, the cross-sectional area of each sound-absorbing groove is different.

[0010] In some embodiments, the angle between the line connecting the center of each of the two adjacent welding grooves and the center of the middle blade is β, and the sound-absorbing groove is arranged between the two welding grooves only when β≥9°.

[0011] Alternatively, the sound-absorbing groove is arranged between each of the two adjacent welding grooves.

[0012] In some embodiments, the three welding grooves arranged in sequence along the circumference of the disc are a first welding groove, a second welding groove, and a third welding groove.

[0013] The sound-absorbing groove includes a first sound-absorbing groove between the first welding groove and the second welding groove and a second sound-absorbing groove between the second welding groove and the third welding groove.

[0014] In a cross section perpendicular to the axial direction of the middle blade, the angle between the line connecting the center of each of the first sound-absorbing groove and the second sound-absorbing groove and the center of the middle blade is θ, the angle between the line connecting the center of each of the first welding groove and the second welding groove and the center of the middle blade is β1, and the angle between the line connecting the center of each of the second welding groove and the third welding groove and the center of the middle blade is β2; wherein θ=(β1+β2) / 2.

[0015] In some embodiments, the depth h of the sound-absorbing groove satisfies 0.5mm≤h≤2mm.

[0016] And / or, the distance d between the sound-absorbing groove and the adjacent welding groove satisfies 1mm≤d≤1.2mm.

[0017] In some embodiments, in a cross section perpendicular to the axial direction of the middle blade, the cross-sectional profile of the sound-absorbing groove has opposite first and second curves, both of which are connected by a first circular arc near the center of the middle blade, and both of which are connected by a second circular arc away from the center of the middle blade.

[0018] Wherein the distance between the center of the first circular arc and the center of the middle blade is equal to the inner diameter D1 of the blade, the distance between the center of the second circular arc and the center of the middle blade is D2, and the outer diameter of the blade is D3, wherein D2≤0.95D3.

[0019] In some embodiments, the first curve is a convex curve, and the convex curve is consistent with the convex direction of both the convex surface of the blade.

[0020] And / or, the second curve is a concave curve, and the concave curve is consistent with the concave direction of both the concave surface of the blade.

[0021] In some embodiments, the distance L between the first curve and the second curve gradually increases in a direction approaching the center of the mid-section blade, and the distance L between the first curve and the second curve satisfies: 0.6mm≤L≤2.85mm.

[0022] In some embodiments, in a cross-section perpendicular to the axial direction of the mid-section blade, the centerline of the cross-sectional profile of the blade comprises two or more circular arcs connected in sequence, each circular arc has different radius and central angle, wherein the center of the maximum thickness of the blade is located on the circular arc on the side of the centerline away from the center of the mid-section blade; and in a direction approaching the center of the mid-section blade, the thickness of the blade gradually increases to a maximum, and then gradually decreases.

[0023] In a second aspect, embodiments of the present application provide a cross-flow blade, which can include any of the above-mentioned mid-section blades.

[0024] In a third aspect, embodiments of the present application provide an air conditioner, which can include any of the above-mentioned cross-flow blades.

[0025] By the above technical solutions, the mid-section blade, the cross-flow blade and the air conditioner of the present application have at least the following beneficial effects:

[0026] 1. In the technical solution provided by the present application, the sound-absorbing groove is arranged between the two adjacent welding grooves, so that the airflow can flow through the sound-absorbing groove when the cross-flow blade rotates. The sound-absorbing groove can change the frequency of the collision between the airflow and the wall of the disc, reduce the aerodynamic noise when the cross-flow blade rotates, and improve the noise quality of the air conditioner when the cross-flow blade is applied to the air conditioner. In addition, the center line of the sound-absorbing groove is parallel to the axis of the mid-section blade, the airflow flows into the cross-flow blade along the radial direction when the cross-flow blade rotates, and the center line of the sound-absorbing groove is perpendicular to the airflow direction, so that the sound-absorbing groove can form a sound-absorbing cavity structure to absorb the airflow, thereby further reducing the propagation of noise. In addition, by opening the sound-absorbing groove on the disc, the weight of the disc is reduced, so that the power consumption of the cross-flow blade can be reduced. When the cross-flow blade is applied to the air conditioner, the power of the air conditioner can be reduced.

[0027] 2. By designing the shape of the blade, the inlet angle of the airflow can be changed and the separation vortex on the surface of the blade can be reduced, thereby reducing the power loss and improving the air volume, reducing the vortex noise on the surface of the blade, and further improving the noise effect.

[0028] The above description is only a summary of the technical solutions of the present application. In order to more clearly understand the technical means of the present application and can be implemented according to the content of the specification, the following will be described in detail with the preferred embodiments of the present application and with the help of the accompanying drawings. BRIEF DESCRIPTION OF DRAWINGS

[0029] In order to make the technical solutions in the embodiments of the present application or the prior art clearer, the accompanying drawings needed in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description only show some embodiments of the present application, and for those skilled in the art, other drawings can be obtained from the structures shown in the drawings without any creative effort.

[0030] Figure 1 is a structure diagram of a cross-flow fan blade in the prior art;

[0031] Figure 2 is a structure diagram of a middle-section fan blade in the prior art;

[0032] Figure 3 is a structure diagram of a middle-section fan blade provided by an embodiment of the present application;

[0033] Figure 4 is a plan view of the middle-section fan blade;

[0034] Figure 5 is Figure 4 an enlarged diagram of position A in the middle-section fan blade;

[0035] Figure 6 is Figure 4 a sectional view of C-C in the middle-section fan blade;

[0036] Figure 7 is Figure 6 an enlarged diagram of position B in the middle-section fan blade;

[0037] Figure 8 is a structure diagram of a fan blade;

[0038] Figure 9 shows a comparison diagram of noise effects of an existing cross-flow fan blade and a cross-flow fan blade of the present application.

[0039] The accompanying drawings are as follows: 1, sound-absorbing groove; 2, welding groove; 3, disc; 4, blade; 11, first sound-absorbing groove; 12, second sound-absorbing groove; 21, first welding groove; 22, second welding groove; 23, third welding groove; 31, first side; 32, second side; 41, first a circular arc; 42, second a circular arc; 43, convex surface of the blade; 44, concave surface of the blade; 101, first curve; 102, second curve; 103, first circular arc; 104, second circular arc. DETAILED DESCRIPTION

[0040] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0043] like Figure 3 and Figure 6 As shown, an embodiment of the present invention provides a mid-section wind turbine blade, which includes a disk 3 having a first side 31 and a second side 32 facing away from each other. The first side 31 is provided with blades 4, which can be integrally formed on the disk 3. The second side 32 is provided with welding grooves 2 for welding to blades 4 on another mid-section wind turbine blade. The number of welding grooves 2 is two or more, and they are arranged sequentially at intervals along the circumference of the disk 3. Preferably, the size of each welding groove 2 is the same, and the number of welding grooves 2 is the same as the number of blades 4.

[0044] The second side 32 is also provided with a noise-absorbing groove 1, which is located between two adjacent welding grooves 2.

[0045] In the above example, by arranging the sound-absorbing groove 1 between the two adjacent welding grooves 2, the airflow can flow through the sound-absorbing groove 1 when the cross-flow fan blade rotates. The sound-absorbing groove 1 can change the frequency of the airflow colliding with the wall of the disc 3, reduce the aerodynamic noise when the cross-flow fan blade rotates, and improve the noise quality of the air conditioner when the cross-flow fan blade is applied to the air conditioner. In addition, the center line of the sound-absorbing groove 1 is parallel to the axis of the middle blade, and the airflow flows into the cross-flow fan blade along the radial direction when the cross-flow fan blade rotates. The center line of the sound-absorbing groove 1 is perpendicular to the direction of the airflow, so that the sound-absorbing groove 1 can form a sound-absorbing cavity structure to absorb the airflow, thereby further reducing the propagation of noise. In addition, by opening the sound-absorbing groove 1 on the disc 3, the weight of the disc 3 is reduced, so that the power consumption of the cross-flow fan blade can be reduced. When the cross-flow fan blade is applied to the air conditioner, the power of the air conditioner can be reduced.

[0046] It should be noted that in the case of a fixed existing blade structure mold, in order to maintain the structure of the existing blade structure mold, the modification cost of the mold is reduced. The above-mentioned sound-absorbing groove 1 is preferably a cutout arranged on the disc 3. Specifically, the existing blade structure mold can be used to integrally injection mold the middle blade, and then the injection molded middle blade can be sent to a milling machine or the like for cutting processing to cut the sound-absorbing groove 1 on the second side 32 of the disc 3. Therefore, the above-mentioned sound-absorbing groove 1 can also be called a sound-absorbing cutout or a cutout.

[0047] As shown in Figure 3 , the number of the foregoing sound-absorbing grooves 1 can be two or more, and are arranged in sequence and spaced apart along the circumference of the disc 3. In the cross section perpendicular to the axial direction of the middle blade, the cross-sectional area of each sound-absorbing groove 1 is different.

[0048] In the above example, by arranging a larger number of sound-absorbing grooves 1, the aerodynamic noise when the cross-flow fan blade rotates can be further reduced. In addition, by making the cross-sectional area of each sound-absorbing groove 1 different, the frequency of the airflow colliding with the wall of the disc 3 when the cross-flow fan blade rotates can be further changed, thereby further reducing the aerodynamic noise when the cross-flow fan blade rotates.

[0049] In a specific application example, as shown in Figure 4 , the centers of the two adjacent welding grooves 2 are connected with the center of the middle blade, and the included angle between the two lines is β. Among them, only the sound-absorbing groove 1 is arranged between the two welding grooves 2 with β≥9°. In other words, no sound-absorbing groove 1 is arranged between the two welding grooves 2 with β less than 9°.

[0050] In the above example, when the included angle β between the two welding grooves 2 is greater than or equal to 9°, the area between the two welding grooves 2 is relatively spacious, thereby facilitating the processing of the sound-absorbing groove 1.

[0051] It should be noted that the center of the welding groove 2 can refer to the center of the circular arc of the welding groove 2 on the side close to the center of the middle blade.

[0052] In another example, in the case of ensuring the overall strength of the middle blade and the distance d between the sound reduction groove 1 and the welding groove 2, the aforementioned sound reduction groove 1 can be arranged between each two adjacent welding grooves 2, so that a larger number of sound reduction grooves 1 can further reduce the aerodynamic noise when the cross-flow fan blade rotates.

[0053] It should be noted that in order to facilitate processing, only one sound reduction groove 1 is arranged between the aforementioned two adjacent welding grooves 2.

[0054] In a specific application example, as shown in Figure 4 The aforementioned three welding grooves 2 arranged in sequence along the circumference of the disc 3 are respectively a first welding groove 21, a second welding groove 22, and a third welding groove 23. The sound reduction groove 1 includes a first sound reduction groove 11 located between the first welding groove 2 and the second welding groove 2, and a second sound reduction groove 12 located between the second welding groove 2 and the third welding groove 2.

[0055] In the cross section perpendicular to the axial direction of the middle blade, the centers of the first sound reduction groove 11 and the second sound reduction groove 12 are respectively connected with the center of the middle blade, and the included angle between the two connecting lines is θ. The centers of the first welding groove 21 and the second welding groove 22 are respectively connected with the center of the middle blade, and the included angle between the two connecting lines is β1. The centers of the second welding groove 22 and the third welding groove 23 are respectively connected with the center of the middle blade, and the included angle between the two connecting lines is β2. Among them, θ=(β1+β2) / 2.

[0056] In the above example, through the above angle setting, the sound reduction groove 1 can be located at the center position between the two adjacent welding grooves 2, the distance between the sound reduction groove 1 and the two adjacent welding grooves 2 is equal, so that the mass distribution uniformity on the disc 3 can be improved, which is beneficial to further reduce the aerodynamic noise when the cross-flow fan blade rotates. And by arranging the sound reduction groove 1 at the center position between the two adjacent welding grooves 2, the processing of the sound reduction groove 1 is also facilitated.

[0057] It should be noted that the center of each sound reduction groove 1 can refer to the center of the circular arc of the sound reduction groove 1 on the side close to the center of the middle blade. The center of each welding groove 2 can refer to the center of the circular arc of the welding groove 2 on the side close to the center of the middle blade.

[0058] As shown in Figure 6 and Figure 7As shown, in a cross-section parallel to the axial direction of the middle section blade, the cross-sectional profile of the noise-absorbing groove 1 is U-shaped. In a specific application example, the depth h of the aforementioned noise-absorbing groove 1 satisfies: 0.5mm ≤ h ≤ 2mm. This design ensures that the depth h of the noise-absorbing groove 1 is neither too small, thus having an insignificant effect on reducing aerodynamic noise, nor too large, thus affecting the strength of the disk 3 and the middle section blade.

[0059] like Figure 5 As shown, the distance d between the aforementioned silencing groove 1 and the adjacent welding groove 2 satisfies: 1mm≤d≤1.2mm. This ensures that the distance d between the silencing groove 1 and the adjacent welding groove 2 is not too small and easily deformed, nor too large and the silencing groove 1 does not significantly reduce aerodynamic noise.

[0060] like Figure 5 As shown, in a cross-section perpendicular to the axial direction of the middle section of the fan blade, the cross-sectional profile of the aforementioned noise-absorbing groove 1 has opposing first curves 101 and second curves 102. The first curve 101 and the second curve 102 are connected by a first arc 103 on the side near the center of the middle section of the fan blade. The first curve 101 and the second curve 102 are connected by a second arc 104 on the side away from the center of the middle section of the fan blade. Wherein, as... Figure 4 As shown, the distance between the center of the first arc 103 and the center of the middle section of the blade is equal to the inner diameter D1 of the blade 4. That is, the center of the first arc 103 of the cross-sectional profile of each noise-absorbing groove 1 is located on the circle of the inner diameter D1 of the blade 4. The distance between the center of the aforementioned second arc 104 and the center of the middle section of the blade is D2, and the outer diameter of the blade 4 is D3, where D2≤0.95D3.

[0061] In the above example, when there are two or more noise-reducing grooves 1, the center of the first arc 103 of the cross-sectional profile of each noise-reducing groove is located on the circle of the inner diameter D1 of the blade 4. This allows each noise-reducing groove 1 to be machined starting from the circle of the inner diameter D1 of the blade 4, ensuring a consistent starting point for machining each groove and facilitating the machining of each groove 1. Furthermore, by ensuring that D2 ≤ 0.95D3, the machining position of the second arc 104 can be controlled, preventing the second arc 104 from becoming too large and deformed.

[0062] It should be noted that in the cross section perpendicular to the axial direction of the middle section blade, the distance D2 between the center of the second arc 104 of the cross section profile of each of the two noise-absorbing grooves 1 and the center of the middle section blade is not equal, so that the area of ​​the cross section profile of each noise-absorbing groove 1 is different, thereby further changing the frequency of the airflow colliding with the wall of the disk 3 when the cross-flow blade rotates, and further reducing the aerodynamic noise when the cross-flow blade rotates.

[0063] In a specific application example, such asFigure 5 As shown, the aforementioned first curve 101 is a convex curve, and the convex direction of this convex curve is consistent with that of the convex surface 43 of the blade. The aforementioned second curve 102 can be a concave curve, and the concave curve is consistent with that of the concave surface 44 of the blade.

[0064] In the above example, through the above settings, the noise-reducing groove 1 can have a similar shape to the blade 4. Since the shape of the blade 4 can reduce noise in the airflow, the noise-reducing groove 1 with a similar shape can further reduce noise in the airflow by matching the shape of the blade 4. Figure 9 The image shows a noise comparison between a conventional cross-flow fan blade and the cross-flow fan blade of the present invention, which employs the aforementioned silencing groove shape. From... Figure 9 As can be seen from the above, under the same air volume, the cross-flow fan blade with the above-mentioned sound-absorbing groove has lower noise, and can generally reduce the fan blade noise by at least 1-1.5 dBA.

[0065] like Figure 5 As shown, along the direction close to the center of the middle section of the fan blade, the distance L between the first curve 101 and the second curve 102 gradually increases. Thus, along the path of the airflow through the silencing groove 1, the volume of the silencing groove 1 gradually increases, which can play a role in gradually expanding the airflow, thereby further silencing and reducing noise of the airflow.

[0066] In a specific application example, the distance L between the first curve 101 and the second curve 102 satisfies: 0.6mm≤L≤2.85mm. This ensures that the distance L between the first curve 101 and the second curve 102 is not too large and would affect the strength of the blade 4, nor too small and would make the noise reduction effect of the silencing groove 1 on aerodynamic noise insignificant.

[0067] like Figure 8 As shown, in a cross-section perpendicular to the axial direction of the middle section blade, the centerline of the cross-sectional profile of the aforementioned blade 4 comprises two or more sequentially connected arcs, each with a different radius and central angle. The center O of the blade 4 at its maximum thickness is located on the arc on the side of the centerline away from the center of the middle section blade. Furthermore, along the direction closer to the center of the middle section blade, the thickness of the blade 4 gradually increases to its maximum and then gradually decreases.

[0068] In a specific application example, such as Figure 8As shown, in a cross-section perpendicular to the axial direction of the middle section blade, the centerline of the cross-sectional profile of the aforementioned blade 4 is composed of a first a-circular arc 41 and a-circular arc 42 connected sequentially. The central angle of the first a-circular arc 41 is θ1, and the radius of the first a-circular arc 41 is r1. The central angle of the second a-circular arc 42 is θ2, and the radius of the first a-circular arc 41 is r2. The radii and central angles of the first a-circular arc 41 and the second a-circular arc 42 are not the same; that is, θ1 is not equal to θ2, and r1 is not equal to r2. The first a-circular arc 41 is farther from the center of the middle section blade relative to the second a-circular arc 42, and the center of the maximum thickness of the blade 4 is located on the first a-circular arc 41.

[0069] In the example above, by designing the shape of blade 4, the airflow inlet angle can be changed and the separation vortex on the surface of blade 4 can be reduced, thereby reducing power loss and increasing air volume, reducing vortex noise on the surface of blade 4, and further improving noise performance.

[0070] An embodiment of the present invention also proposes a cross-flow fan blade, which may include any of the aforementioned middle-section fan blades. Because the cross-flow fan blade uses the aforementioned middle-section fan blade, by providing a sound-absorbing groove 1 between two adjacent welding slots 2, the airflow can flow through the sound-absorbing groove 1 when the cross-flow fan blade rotates. This sound-absorbing groove 1 can change the frequency of airflow collision with the wall of the disc 3, reducing the aerodynamic noise when the cross-flow fan blade rotates. When the cross-flow fan blade is applied to an air conditioner, it can improve the noise quality of the air conditioner. Furthermore, the centerline of the sound-absorbing groove 1 is parallel to the axis of the middle-section fan blade. When the cross-flow fan blade rotates, the airflow flows radially into the interior of the cross-flow fan blade. The centerline of the sound-absorbing groove 1 intersects perpendicularly with the airflow direction, thus forming a sound-absorbing cavity structure to silence the flowing airflow, thereby further reducing noise propagation. Additionally, by creating the sound-absorbing groove 1 on the disc 3, the weight of the disc 3 is reduced, thus reducing the power consumption of the cross-flow fan blade. When the cross-flow fan blade is applied to an air conditioner, the power consumption of the air conditioner can be reduced.

[0071] An embodiment of the present invention also provides an air conditioner that may include any of the cross-flow fan blades described above. Because the air conditioner uses the aforementioned cross-flow fan blades, aerodynamic noise can be reduced.

[0072] For ease of understanding, the overall structure of the present invention will be described below, and its working principle will be explained.

[0073] The application is to design a middle section wind blade and a cross flow fan blade using the middle section wind blade, which can be used in an air conditioner. The middle section wind blade is provided with a plurality of spaced apart sound absorbing grooves 1 on the side of a disc 3 away from a blade 4. The sound absorbing grooves 1 are of different sizes and can be formed by cutting. The sound absorbing grooves 1 are concave structures on the disc 3 except the welding grooves 2. The sound absorbing grooves 1 are arranged between two adjacent welding grooves 2. The included angle between the centers of the two adjacent welding grooves 2 and the center of the middle section wind blade is β. The sound absorbing grooves 1 are arranged only between the two welding grooves 2 with β≥9°. The included angle between the two sound absorbing grooves 1 is designed in relation to the included angle between the three adjacent welding grooves 2. The sound absorbing grooves 1 are stretched to the side of the disc 3 close to the blade 4 along the axial direction of the cross flow fan blade with a depth h. In the cross section perpendicular to the axial direction of the middle section wind blade, the cross section profile of the sound absorbing grooves 1 has a first curve 101 and a second curve 102. The first curve 101 and the second curve 102 are connected by a first circular arc 103 on the side close to the center of the middle section wind blade. The first curve 101 and the second curve 102 are connected by a second circular arc 104 on the side away from the center of the middle section wind blade. The first curve 101 is a convex curve and the second curve 102 is a concave curve. The shapes of the first curve 101 and the second curve 102 are designed as irregular curves. The center of the second circular arc 104 is away from the center of the middle section wind blade with a distance less than the outer diameter of the welding groove 2.

[0074] The side of the disc 3 away from the sound absorbing grooves 1 is provided with the blade 4. In the cross section perpendicular to the axial direction of the middle section wind blade, the center line of the cross section profile of the blade 4 is a non-circular arc structure composed of two or more circular arcs. The center of the blade 4 at the maximum thickness is located close to the front end of the center line. The front end of the center line refers to the end of the center line away from the center of the middle section wind blade. The shape of the welding groove 2 is designed to be the same as that of the blade 4. The sound absorbing grooves 1 are arranged between the welding grooves 2.

[0075] The above newly designed blade structure can improve the boundary layer and airflow separation of the blade surface, thereby reducing power loss, increasing air volume, and reducing vortex noise of the air conditioner.

[0076] The cross flow fan blade designed by the application can reduce the weight of the cross flow fan blade by designing the sound absorbing groove structure, thereby reducing the power of the air conditioner and reducing the fan noise by at least 1-1.5dBA.

[0077] The above only describes the preferred embodiments of the application and does not limit the patent scope of the application. Any equivalent structural transformation made according to the application concept, the content of the specification and the drawings, or direct / indirect application in other related technical fields is included in the patent protection scope of the application.

Claims

1. A medium-section wind turbine blade, characterized in that, The device includes a disc (3) having a first side (31) and a second side (32) facing away from each other. The first side (31) is provided with blades (4), and the second side (32) is provided with welding grooves (2) for welding with blades (4) on another middle section of the fan blade. The number of welding grooves (2) is two or more, and they are arranged alternately along the circumference of the disc (3). The second side (32) is also provided with a noise-absorbing groove (1), which is located between two adjacent welding grooves (2). The number of the noise-absorbing grooves (1) is two or more, and they are arranged sequentially at intervals along the circumference of the disc (3); in the cross section perpendicular to the axial direction of the middle section blade, the area of ​​the cross section profile of each noise-absorbing groove (1) is different.

2. The middle-section fan blade as described in claim 1, characterized in that, The angle between the lines connecting the center of two adjacent welding grooves (2) and the center of the middle section fan blade is β, wherein the sound-absorbing groove (1) is provided only between two welding grooves (2) with β≥9°; Alternatively, the aforementioned sound-absorbing groove (1) may be provided between each pair of adjacent welding grooves (2).

3. The middle-section fan blade as described in claim 1, characterized in that, The three welding grooves (2) arranged sequentially along the circumference of the disk (3) are the first welding groove (21), the second welding groove (22) and the third welding groove (23); The noise-reducing groove (1) includes a first noise-reducing groove (11) located between the first welding groove (21) and the second welding groove (22) and a second noise-reducing groove (12) located between the second welding groove (22) and the third welding groove (23); In a cross section perpendicular to the axial direction of the middle section fan blade, the angle between the lines connecting the centers of the first silencing groove (11) and the second silencing groove (12) to the center of the middle section fan blade is θ, the angle between the lines connecting the centers of the first welding groove (21) and the second welding groove (22) to the center of the middle section fan blade is β1, and the angle between the lines connecting the centers of the second welding groove (22) and the third welding groove (23) to the center of the middle section fan blade is β2; where θ = (β1 + β2) / 2.

4. The middle-section wind turbine blade as described in claim 1, characterized in that, The depth h of the noise-absorbing groove (1) satisfies: 0.5 mm ≤ h ≤ 2 mm; And / or, the distance d between the silencing groove (1) and the adjacent welding groove (2) satisfies: 1 mm ≤ d ≤ 1.2 mm.

5. The medium-section wind turbine blade as described in claim 1, characterized in that, In a cross section perpendicular to the axial direction of the middle section blade, the cross section profile of the silencing groove (1) has a first curve (101) and a second curve (102) with opposite curves. The first curve (101) and the second curve (102) are connected by a first arc (103) on the side near the center of the middle section blade, and the first curve (101) and the second curve (102) are connected by a second arc (104) on the side away from the center of the middle section blade. Wherein, the distance between the center of the first arc (103) and the center of the middle section of the blade is equal to the inner diameter D1 of the blade (4), the distance between the center of the second arc (104) and the center of the middle section of the blade is D2, and the outer diameter of the blade (4) is D3, wherein D2≤0.95D3.

6. The middle section fan blade as described in claim 5, characterized in that, The first curve (101) is a convex curve, and the convex curve and the convex surface of the blade (4) have the same convex direction. And / or, the second curve (102) is a concave curve, and the concave curve and the concave surface of the blade (4) are in the same concave direction.

7. The middle-section wind turbine blade as described in claim 5, characterized in that, Along the direction close to the center of the middle section blade, the distance L between the first curve (101) and the second curve (102) gradually increases, and the distance L between the first curve (101) and the second curve (102) satisfies: 0.6mm≤L≤2.85mm.

8. The middle section wind turbine blade as described in any one of claims 1 to 7, characterized in that, In a cross section perpendicular to the axial direction of the middle section blade, the centerline of the cross section profile of the blade (4) includes two or more arcs connected in sequence, each arc having a different radius and central angle. The center of the maximum thickness of the blade (4) is located on the arc on the side of the centerline away from the center of the middle section blade. Along the direction close to the center of the middle section blade, the thickness of the blade (4) gradually increases to the maximum and then gradually decreases.

9. A cross-flow fan blade, characterized in that, Includes the middle section of the wind turbine blade as described in any one of claims 1 to 8.

10. An air conditioner, characterized in that, Includes the cross-flow fan blades as described in claim 9.

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