Axial flow fan blade, axial flow fan and air conditioner

Abstract

The present application relates to an axial flow fan blade, an axial flow fan and an air conditioner. An axial flow fan blade comprises: a hub; a blade, which is arranged on the circumference of the hub; the blade has a blade root, a blade top, a leading edge and a trailing edge, the blade root is connected to the circumference of the hub, and the leading edge and the trailing edge are relatively connected between the blade top and the blade root; wherein the trailing edge is provided with a plurality of saw teeth, and each of the saw teeth is connected by an arc segment; the trailing edge is divided into a plurality of adjacent edge areas from the blade root to the blade top, the arcs of each of the arc segments in the same edge area are equal, and the arcs of the arc segments in different edge areas gradually increase from the blade root to the blade top. An axial flow fan comprises the above-mentioned axial flow fan blade and an air guide ring, and the axial flow fan blade is arranged in the air guide ring. An air conditioner comprises the above-mentioned axial flow fan. The above-mentioned axial flow fan blade, axial flow fan and air conditioner can reduce the aerodynamic noise by weakening the trailing edge shedding vortex of the axial flow fan blade.

Description

Technical Field

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

[0002] At present, axial flow fans are widely used in various air handling equipment. Their working efficiency and various performances have an important impact on the energy efficiency and comfort of air handling equipment.

[0003] Vortex detachment will occur on the surface of the wind blade, which is particularly obvious at the trailing edge of the blade. Vortex detachment will cause random lift pulsation and interfere with the radial airflow, which can easily generate broadband vortex noise and affect the performance of the wind blade. Summary of the invention

[0004] Based on this, it is necessary to provide an axial flow fan blade, an axial flow fan and an air conditioner to address the problem of how to reduce the noise at the trailing edge of the blade.

[0005] An axial flow fan blade, comprising:

[0006] Wheel hub;

[0007] A blade is arranged on the circumferential side of the hub; the blade has a blade root, a blade tip, a leading edge and a trailing edge, the blade root is connected to the circumferential side of the hub, and the leading edge and the trailing edge are relatively connected between the blade tip and the blade root;

[0008] Among them, the trailing edge is provided with a plurality of serrations, and each of the serrations is connected by an arc segment; the trailing edge is divided into a plurality of adjacent edge areas from the blade root to the blade top, the curvature of each arc segment in the same edge area is equal, and the curvature of the arc segments in different edge areas gradually increases from the blade root to the blade top.

[0009] The serrated structure arranged at the trailing edge of the above-mentioned axial flow fan blade can effectively cut the vortex shedding generated by rotation, reduce the number and size of the vortex shedding at the trailing edge, and reduce the aerodynamic noise of the fan blade; the arc segment curvature of the serrations in different edge areas gradually increases from the blade root to the blade top, weakening the vortex shedding at the trailing edge while ensuring the air volume when the axial flow fan blade rotates.

[0010] In one embodiment, each of the saw teeth includes a first straight line segment, a second straight line segment and an arc segment, the first straight line segment and the second straight line segment are set at an angle, the arc segment is connected to the end of the second straight line segment, the length of the second straight line segment is the tooth height h of the saw tooth, and the distance between the endpoints of the first straight line segment and the second straight line segment is the tooth width w of the saw tooth.

[0011] In one embodiment, each of the saw teeth further includes a connecting segment, and the first straight line segment and the second straight line segment are connected by the connecting segment.

[0012] In one of the embodiments, the curvatures of the connecting segments in the same edge region are equal, and the curvatures of the connecting segments in different edge regions gradually increase from the blade root to the blade tip.

[0013] In one embodiment, the tooth tip of each sawtooth is located on the trailing edge fitting curve, and the angle between the first straight line segment and the tangent of the trailing edge fitting curve is the inclination angle θ of the sawtooth.

[0014] In one embodiment, the inclination angle θ of each sawtooth in the same edge region, the tooth width w of the sawtooth, and the tooth height h of the sawtooth change linearly or are equal.

[0015] In one embodiment, the inclination angle θ of the sawtooth ranges from 25 degrees to 60 degrees.

[0016] In one embodiment, the chord length of the blade is L, the tooth height h of the sawtooth is in the range of 0.05L to 0.15L, and the arc length l of the circular arc segment is in the range of 0.1h to 0.15h.

[0017] In one of the embodiments, the tooth thickness of the sawtooth gradually decreases from the leading edge to the trailing edge.

[0018] In one of the embodiments, the tooth thickness of the sawtooth gradually decreases from the blade root to the blade tip.

[0019] In one of the embodiments, the cross-section obtained by the intersection of a cylindrical surface concentric with the cylindrical surface of the hub and the blade is the profile of the blade, the number of the profiles is four, and the four profiles divide the trailing edge from the blade root to the blade top into three edge areas.

[0020] In one embodiment, the length of the first edge zone is L1, the number of saw teeth in the first edge zone is n1, and the tooth width w1 of the saw teeth in the first edge zone is in the range of (0.2-1)*L1 / n1; the length of the second edge zone is L2, the number of saw teeth in the second edge zone is n2, and the tooth width w2 of the saw teeth in the second edge zone is in the range of (0.5-1.5)*L2 / n2; the length of the third edge zone is L3, the number of saw teeth in the third edge zone is n3, and the tooth width w3 of the saw teeth in the third edge zone is in the range of (0.8-2)*L3 / n3.

[0021] In one embodiment, the number of saw teeth n1, n2, and n3 are all in the range of 2 to 10.

[0022] In one embodiment, the position of the first profile is (r-Ra) / (Rb-Ra)=12.5%, the position of the second profile is (r-Ra) / (Rb-Ra)=37.5%, the position of the third profile is (r-Ra) / (Rb-Ra)=62.5%, and the position of the fourth profile is (r-Ra) / (Rb-Ra)=87.5%, wherein r is the cylindrical radius of the hub, Ra is the radius of a virtual cylinder concentric with the cylindrical surface of the hub, and Rb is the cylindrical radius of the blade tip.

[0023] In one embodiment, the blade has a suction surface and a pressure surface facing away from the suction surface, and the suction surface is provided with a plurality of recessed portions with different recessed depths.

[0024] In one embodiment, the recessed portions are spaced side by side from the blade root to the blade top and the blades have similar shapes. The edges of the recessed portions are spaced apart from the leading edge, the trailing edge, the blade top and the blade root.

[0025] In one embodiment, the first recessed portion is within a first region defined by the first profile and the second profile, the second recessed portion is within a second region defined by the second profile and the third profile, and the third recessed portion is within a second region defined by the third profile and the fourth profile.

[0026] In one embodiment, the average thickness of the blades in the first region is H1, and the depression depth of the first recessed portion ranges from 0.15H1 to 0.35H1; the average thickness of the blades in the second region is H2, and the depression depth of the second recessed portion ranges from 0.15H2 to 0.35H2; the average thickness of the blades in the third region is H3, and the depression depth of the third recessed portion ranges from 0.15H3 to 0.35H3.

[0027] In one embodiment, the blade has a suction surface and a pressure surface facing away from the suction surface, and a bending portion is provided on the blade near the blade top, and the bending portion is folded from the pressure surface toward the suction surface.

[0028] In one of the embodiments, the bending portion is arranged in a fourth area defined by the fourth profile and the blade tip, and the bending angle gradually increases and then gradually decreases from the leading edge to the trailing edge.

[0029] In one embodiment, a first section, a second section and a third section are cut on the blade from the blade root to the blade top, and the bending angle of the first bend on the first section is smaller than the bending angle of the second bend on the second section, and the bending angle of the second bend on the second section is larger than the bending angle of the third bend on the third section.

[0030] In one of the embodiments, the thickness of the blade gradually decreases from the blade root to the blade tip.

[0031] An axial flow fan comprises the above-mentioned axial flow fan blade and an air guide ring, wherein the axial flow fan blade is arranged in the air guide ring.

[0032] The above-mentioned axial flow fan weakens the trailing edge shedding vortex of the axial flow fan blade, thereby reducing the aerodynamic noise of the fan blade.

[0033] An air conditioner comprises the above-mentioned axial flow fan.

[0034] The above-mentioned air conditioner weakens the trailing edge shedding vortex of the axial flow fan blade and can reduce the aerodynamic noise of the axial flow fan. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a first schematic diagram of an axial flow fan blade in an embodiment;

[0036] Figure 2 for Figure 1 A second schematic diagram of an axial flow fan blade is shown;

[0037] Figure 3 for Figure 1 A schematic diagram of the edge area of ​​the axial flow fan blade shown;

[0038] Figure 4 for Figure 3 Schematic diagram of the serrations in the blade shown;

[0039] Figure 5 for Figure 4 A schematic diagram of the profile of the blade shown;

[0040] Figure 6 for Figure 1 A schematic diagram of the blade bending portion of an axial flow fan blade is shown;

[0041] Figure 7 for Figure 1 A schematic diagram of a blade in an axial flow fan blade is shown;

[0042] Figure 8 for Figure 7 a cross-sectional view of a first section of the blade shown;

[0043] Fig. 9 for Figure 7 a cross-sectional view of a second section of the blade shown;

[0044] Fig.10 for Figure 7 a cross-sectional view of a third section of the blade shown;

[0045] Fig.11This is a schematic diagram of the linear variation of the chord length L of the blade and the percentage of the blade height.

[0046] Reference numerals:

[0047] 100, hub; 200, blade; 210, blade root; 220, blade tip; 230, leading edge; 240, trailing edge; 250, edge area; 251, first edge area; 252, second edge area; 253, third edge area; 260, suction surface; 261, recessed portion; 261a, first recessed portion; 261b, second recessed portion; 261c, third recessed portion; 270, pressure surface; 280, bending portion; 281, first bending portion; 28 2. Second bending point; 283. Third bending point; 300. Sawtooth; 301. Arc segment; 302. First straight line segment; 303. Second straight line segment; 304. Connecting segment; S1. First profile; S2. Second profile; S3. Third profile; S4. Fourth profile; A1. First area; A2. Second area; A3. Third area; A4. Fourth area; θ. Sawtooth inclination angle; w. Sawtooth tooth width; h. Sawtooth tooth height; d. Sawtooth tooth thickness. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0049] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0050] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0051] In this application, unless otherwise clearly specified and limited, the terms "initial", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0052] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0053] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0054] Please refer to Figure 1 The axial flow fan blade in one embodiment includes a hub 100 and a blade 200, and the blade 200 is arranged on the circumference of the hub 100. The blade 200 has a blade root 210, a blade tip 220, a leading edge 230 and a trailing edge 240, the blade root 210 is connected to the circumference of the hub 100, and the leading edge 230 and the trailing edge 240 are relatively connected between the blade tip 220 and the blade root 210.

[0055] Among them, combined Figure 2 As shown, the trailing edge 240 is provided with a plurality of saw teeth 300, and each saw tooth 300 is connected by an arc segment 301; Figure 3 As shown, the trailing edge 240 is divided into a plurality of adjacent edge areas 250 from the blade root 210 toward the blade tip 220 , the curvature of each arc segment 301 in the same edge area 250 is equal, and the curvature of the arc segment 301 in different edge areas 250 gradually increases from the blade root 210 toward the blade tip 220 .

[0056] It should be noted that during the rotation of the blade 200, vortex shedding will occur on the surface of the blade 200, causing random lift pulsation and disturbing the radial airflow, which is likely to generate broadband vortex noise, thereby affecting the performance of the wind blade. As the airflow flows from the leading edge 230 to the trailing edge 240, strong periodic shedding vortices are likely to be generated, especially at the trailing edge 240 of the blade 200, increasing kinetic energy loss.

[0057] Through the above-mentioned arrangement, the sawtooth 300 structure arranged at the trailing edge 240 can effectively cut the vortex shedding generated by the rotation, reduce the number and size of the vortex shedding at the trailing edge 240, and reduce the aerodynamic noise of the fan blade; the arc segment 301 of the sawtooth 300 in different edge areas 250 gradually increases in curvature from the blade root 210 to the blade top 220, thereby weakening the vortex shedding at the trailing edge 240 while ensuring the wind volume when the axial flow fan blade rotates.

[0058] like Figure 2 In the illustrated embodiment, each sawtooth 300 includes a first straight line segment 302 , a second straight line segment 303 and an arc segment 301 , and the first straight line segment 302 and the second straight line segment 303 are arranged at an angle.

[0059] In this embodiment, if Figure 2 As shown, each sawtooth 300 further includes a connecting segment 304 , and the first straight segment 302 and the second straight segment 303 are connected by the connecting segment 304 .

[0060] It is understandable that the first straight line segment 302 and the second straight line segment 303 in a single sawtooth 300 are connected by a connecting segment 304. Two adjacent sawtooths 300 are connected by an arc segment 301, that is, the end of the first straight line segment 302 of one sawtooth 300 is connected to the arc segment 301 of another adjacent sawtooth 300.

[0061] In other embodiments, the connecting segment 304 may not be provided, and the first straight segment 302 and the second straight segment 303 are directly connected.

[0062] like Figure 2 In the illustrated embodiment, the connecting section 304 is in an arc shape. In other embodiments, the connecting section 304 may also be in a straight line or other shapes.

[0063] like Figure 2 In the illustrated embodiment, the curvatures of the connecting segments 304 in the same edge region 250 are equal, and the curvatures of the connecting segments 304 in different edge regions 250 gradually increase from the blade root 210 to the blade tip 220 .

[0064] Through this arrangement, the vortex shedding of the trailing edge 240 is further weakened while ensuring the air volume when the axial flow fan blades rotate.

[0065] In this embodiment, combined Figure 4As shown, the tip of each sawtooth 300 is located on the fitting curve of the trailing edge 240, and the angle between the first straight segment 302 and the tangent Q of the fitting curve of the trailing edge 240 is the sawtooth inclination angle θ. The distance between the endpoints of the first straight segment 302 and the second straight segment 303 is the sawtooth tooth width w, and the length of the second straight segment 303 is the sawtooth tooth height h.

[0066] In this embodiment, the inclination angle θ, the tooth width w and the tooth height h of each sawtooth in the same edge area 250 may vary linearly. Alternatively, the inclination angle θ, the tooth width w and the tooth height h of each sawtooth in the same edge area 250 may be equal.

[0067] In other embodiments, according to actual use requirements, the inclination angle θ of each sawtooth in the same edge area 250 , the tooth width w of the sawtooth, and the tooth height h of the sawtooth may also be designed as a linear or nonlinear combination of parameters.

[0068] In this embodiment, if Figure 4 As shown, the value range of the inclination angle θ of the sawtooth is 25 degrees to 60 degrees. Through this arrangement, each sawtooth 300 can effectively cut the vortex shedding of the trailing edge 240.

[0069] In this embodiment, combined with Figure 2 and Figure 4 As shown, the chord length of the blade 200 is L, the tooth height h of the sawtooth is in the range of 0.05L to 0.15L, and the arc length l of the arc segment 301 is in the range of 0.1h to 0.15h. With this arrangement, the connection between the sawtooths 300 can be smoothly transitioned through the arc segment 301, and the trailing edge 240 shedding vortex can be effectively cut.

[0070] It should be noted that if Figure 2 As shown, the blade 200 has a suction surface 260 and a pressure surface 270 facing away from the suction surface 260 . The height from the suction surface 260 to the pressure surface 270 is the thickness of the blade 200 , that is, the tooth thickness d of the sawtooth.

[0071] In this embodiment, the chord length L of the blade 200 changes linearly.

[0072] For example, the chord length of the blade 200 increases linearly with the increase of the blade height percentage, and the blade height percentage is defined as (r-Ra) / (Rb-Ra). Figure 5 As shown, Ra is the radius of the cylindrical surface of the hub 100 , r is the radius of the cylindrical surface concentric with the cylindrical surface of the hub 100 , and Rb is the radius of the cylindrical surface of the blade tip 220 .

[0073] When (r-Ra) / (Rb-Ra) takes values ​​of 0%, 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5% and 100%, the corresponding chord length of the blade 200 increases linearly, such as Fig.11 shown.

[0074] like Figure 2 In the illustrated embodiment, the tooth thickness d of the saw teeth gradually decreases from the leading edge 230 to the trailing edge 240. Through this arrangement, the weight of the fan blade and the load can be reduced while ensuring the performance and structural reliability of the fan blade.

[0075] like Figure 2 In another embodiment shown, the tooth thickness d of the sawtooth gradually decreases from the leading edge 230 to the trailing edge 240 , and the tooth thickness d of the sawtooth gradually decreases from the blade root 210 to the blade tip 220 .

[0076] In this embodiment, the thickness of the blade 200 as a whole gradually decreases from the blade root 210 to the blade tip 220, which causes the tooth thickness d of the sawtooth to gradually decrease from the blade root 210 to the blade tip 220. In other embodiments, only the thickness of the portion of the blade 200 provided with the sawtooth 300 may gradually decrease from the blade root 210 to the blade tip 220, and the thickness of the portion of the blade 200 not provided with the sawtooth 300 may be equal.

[0077] like Figure 3 In the illustrated embodiment, the cross section obtained by the intersection of the cylindrical surface concentric with the cylindrical surface of the hub 100 and the blade 200 is the profile of the blade 200. There are four profiles, and the four profiles divide the trailing edge 240 from the blade root 210 to the blade tip 220 into three edge areas 250.

[0078] Specifically, Figure 3 As shown, the position of the first profile S1 is (r-Ra) / (Rb-Ra)=12.5%, the position of the second profile S2 is (r-Ra) / (Rb-Ra)=37.5%, the position of the third profile S3 is (r-Ra) / (Rb-Ra)=62.5%, and the position of the fourth profile S4 is (r-Ra) / (Rb-Ra)=87.5%.

[0079] In other embodiments, the number of profiles may be other values, and the number and position of the profiles may be set according to actual use requirements. For example, the number of profiles may be five, and the five profiles divide the trailing edge 240 from the blade root 210 to the blade tip 220 into four edge areas 250 .

[0080] In this embodiment, if Figure 3As shown, the length of the first edge zone 251 is L1, the number of the saw teeth 300 in the first edge zone 251 is n1, and the tooth width w1 of the saw teeth in the first edge zone 251 is in the range of (0.2~1)*L1 / n1; the length of the second edge zone 252 is L2, the number of the saw teeth 300 in the second edge zone 252 is n2, and the tooth width w2 of the saw teeth in the second edge zone 252 is in the range of (0.5~1.5)*L2 / n2; the length of the third edge zone 253 is L3, the number of the saw teeth 300 in the third edge zone 253 is n3, and the tooth width w3 of the saw teeth in the third edge zone 253 is in the range of (0.8~2)*L3 / n3.

[0081] It should be noted here that if Figure 3 As shown, the length of the first edge zone 251 is the distance between the first profile S1 and the second profile S2, the length of the second edge zone 252 is the distance between the second profile S2 and the third profile S3, and the length of the third edge zone 253 is the distance between the third profile S3 and the fourth profile S4.

[0082] In this embodiment, if Figure 3 As shown, the number n1 of the saw teeth 300 in the first edge region 251 , the number n2 of the saw teeth 300 in the second edge region 252 , and the number n3 of the saw teeth 300 in the third edge region 253 are all in the range of 2-10.

[0083] In this embodiment, the lengths of the first edge region 251, the second edge region 252, and the third edge region 253 are not equal. In other embodiments, the lengths of the first edge region 251, the second edge region 252, and the third edge region 253 may be equal.

[0084] In this embodiment, the number n1 of the saw teeth 300 in the first edge region 251, the number n2 of the saw teeth 300 in the second edge region 252, and the number n3 of the saw teeth 300 in the third edge region 253 are all different. In other embodiments, the number n1 of the saw teeth 300 in the first edge region 251, the number n2 of the saw teeth 300 in the second edge region 252, and the number n3 of the saw teeth 300 in the third edge region 253 may be equal.

[0085] like Figure 3 In the illustrated embodiment, the suction surface 260 is provided with a plurality of recessed portions 261 having different recessed depths.

[0086] Through this arrangement, during the rotation of the blade 200, the recessed portion 261 can inhibit the development of the vortex generated on the surface of the blade 200, reduce the interference of the radial airflow, and weaken the generated broadband vortex noise. At the same time, the structural reliability of the fan blade is ensured, and the weight of the fan blade is further reduced.

[0087] It should be noted that, combined with Figure 2As shown, the recessed portion 261 is formed by the suction surface 260 being recessed downward toward the pressure surface 270 .

[0088] In this embodiment, if Figure 2 As shown, the recessed portions 261 are spaced apart from each other in a direction from the blade root 210 to the blade tip 220 , and a distance is provided between the edge of each recessed portion 261 and the leading edge 230 , the trailing edge 240 , the blade tip 220 and the blade root 210 .

[0089] In a specific embodiment, the distance between the edge of the recessed portion 261 and the leading edge 230 is 0.15L-0.2L, the distance between the edge of the recessed portion 261 and the trailing edge 240 is 0.15L-0.2L, the distance between the edge of the recessed portion 261 and the blade top 220 is 0.08L-0.15L, and the distance between the edge of the recessed portion 261 and the blade top 220 is 0.125L-0.175L.

[0090] like Figure 5 In the illustrated embodiment, the number of the recessed portions 261 is three. The first recessed portion 261a is within the first area A1 defined by the first profile S1 and the second profile S2, the second recessed portion 261b is within the second area A2 defined by the second profile S2 and the third profile S3, and the third recessed portion 261c is within the third area A3 defined by the third profile S3 and the fourth profile S4.

[0091] Specifically, combined Figure 2 As shown, the average thickness of the blade 200 in the first area A1 is H1, and the depression depth of the first recessed portion 261a ranges from 0.15H1 to 0.35H1; the average thickness of the blade 200 in the second area A2 is H2, and the depression depth of the second recessed portion 261b ranges from 0.15H2 to 0.35H2; the average thickness of the blade 200 in the third area A3 is H3, and the depression depth of the third recessed portion 261c ranges from 0.15H3 to 0.35H3.

[0092] In this embodiment, the average thickness of the blade 200 in the first area A1 is H1, the average thickness of the blade 200 in the second area A2 is H2, and the average thickness of the blade 200 in the third area A3 is H3, which decreases in sequence, and the depression depth of the first recessed portion 261a, the depression depth of the second recessed portion 261b, and the depression depth of the third recessed portion 261c increase in sequence. Through this arrangement, the vortex separation generated on the surface of the blade 200 can be better weakened.

[0093] In other embodiments, the average thickness H1 of the blade 200 in the first area A1, the average thickness H2 of the blade 200 in the second area A2, and the average thickness H3 of the blade 200 in the third area A3 may be equal, and the depression depths of the first recessed portion 261a, the second recessed portion 261b, and the third recessed portion 261c may be equal.

[0094] In this embodiment, if Figure 5 As shown, the shapes of the first recessed portion 261a, the second recessed portion 261b and the third recessed portion 261c are similar to the shape of the blade 200, and the edges of each recessed portion 261 are spaced from the leading edge 230, the trailing edge 240, the blade top 220 and the blade root 210. Through this arrangement, the recessed area of ​​the recessed portion 261 is expanded as much as possible within a limited space, so as to better weaken the vortex separation generated on the surface of the blade 200.

[0095] In other embodiments, each recessed portion 261 may also be circular, rectangular or arranged in other ways. Each recessed portion 261 may also be circular or in other irregular shapes.

[0096] During the rotation of the blade 200, due to the existence of the gap at the blade tip 220, part of the fluid at the suction surface 260 will flow to the pressure surface 270 under the action of the pressure difference, thereby generating a leakage vortex at the blade tip 220, increasing kinetic energy loss and noise. Based on the above considerations, Figure 6 As shown, a bending portion 280 is provided near the blade tip 220 of the blade 200 , and the bending portion 280 is folded from the pressure surface 270 to the suction surface 260 .

[0097] Through this arrangement, the airflow leakage rate of the blade tip 220 is effectively reduced, the leakage vortex of the blade tip 220 and the flow pulsation near the blade tip 220 are reduced, thereby improving the fan efficiency and reducing the aerodynamic noise in the medium and low frequency bands.

[0098] like Figure 5 and Figure 6 In the illustrated embodiment, the bent portion 280 is disposed in a fourth area A4 defined by the fourth profile S4 and the blade tip 220 .

[0099] Specific as Figure 1 As shown, the bending portion 280 extends from the front edge 230 to the rear edge 240 , and the bending angle increases from small to large and then decreases from the front edge 230 to the rear edge 240 .

[0100] It is understandable that, combined with Figure 7 As shown, the first section J1, the second section J2 and the third section J3 of the blade 200 are cut from the blade root 210 to the blade tip 220. Figure 8 is a schematic cross-sectional view of the first section J1, Fig. 9 is a cross-sectional schematic diagram of the second section J1, Fig.10 The first bend 281 on the first section J1 has a smaller bending angle than the second bend 282 on the second section J2, and the second bend 282 on the second section J2 has a larger bending angle than the third bend 283 on the third section J3.

[0101] In this embodiment, the number of the blades 200 is at least two, and the blades 200 are evenly distributed around the circumference of the hub 100 .

[0102] Please refer to Figure 1 In one embodiment, the axial flow fan includes an air guide ring and the above-mentioned axial flow fan blades, and the axial flow fan blades are arranged in the air guide ring.

[0103] In a specific implementation, the suction surface 260 of the blade 200 faces the air inlet end of the air guide circle, and the pressure surface 270 of the blade 200 faces the air outlet end of the air guide circle.

[0104] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0105] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be subject to the attached claims.

Claims

1. An axial flow fan blade, characterized in that: include: Wheel hub (100); Blades (200) are arranged on the circumferential side of the hub (100); The blade (200) comprises a blade root (210), a blade tip (220), a leading edge (230) and a trailing edge (240); the blade root (210) is connected to the peripheral side of the hub (100); the leading edge (230) and the trailing edge (240) are relatively connected between the blade tip (220) and the blade root (210); The trailing edge (240) is provided with a plurality of saw teeth (300), each of the saw teeth (300) comprises a first straight line segment (302), a second straight line segment (303) and a circular arc segment (301), the first straight line segment (302) and the second straight line segment (303) being connected via the circular arc segment (301); the trailing edge (240) is divided into a plurality of adjacent edge areas (250) from the blade root (210) toward the blade tip (220), the curvature of each circular arc segment (301) in the same edge area (250) is equal, and the curvature of the circular arc segments (301) in different edge areas (250) gradually increases from the blade root (210) toward the blade tip (220).

2. The axial flow fan blade according to claim 1, characterized in that: The first straight line segment (302) and the second straight line segment (303) are arranged at an angle, the arc segment (301) is connected to the end of the second straight line segment (303), the length of the second straight line segment (303) is the tooth height h of the sawtooth (300), and the distance between the end points of the first straight line segment (302) and the second straight line segment (303) is the tooth width w of the sawtooth (300).

3. The axial flow fan blade according to claim 2, characterized in that: Each of the saw teeth (300) further comprises a connecting section (304), and the saw teeth (300) are connected via the connecting section (304).

4. The axial flow fan blade according to claim 3, characterized in that: Each connecting section (304) is in an arc shape, the curvature of each connecting section (304) in the same edge zone (250) is equal, and the curvature of the connecting sections (304) in different edge zones (250) gradually increases from the blade root (210) to the blade tip (220).

5. The axial flow fan blade according to claim 2, characterized in that: The tooth tip of each saw tooth (300) is located on the trailing edge (240) fitting curve, and the angle between the first straight line segment (302) and the tangent of the trailing edge (240) fitting curve is the inclination angle θ of the saw tooth (300).

6. The axial flow fan blade according to claim 5, characterized in that: The inclination angle θ of each saw tooth (300) in the same edge area (250), the tooth width w of the saw tooth (300) and the tooth height h of the saw tooth (300) change linearly or are equal.

7. The axial flow fan blade according to claim 5, characterized in that: The inclination angle θ of the sawtooth (300) ranges from 25 degrees to 60 degrees.

8. The axial flow fan blade according to claim 2, characterized in that: The chord length of the blade (200) is L, the tooth height h of the sawtooth (300) is in the range of 0.05L to 0.15L, and the arc length l of the circular arc segment (301) is in the range of 0.1h to 0.15h.

9. The axial flow fan blade according to claim 1, characterized in that: The tooth thickness of the sawtooth (300) gradually decreases from the front edge (230) toward the rear edge (240).

10. The axial flow fan blade according to claim 1 or 9, characterized in that: The tooth thickness of the sawtooth (300) gradually decreases from the blade root (210) toward the blade tip (220).

11. The axial flow fan blade according to claim 1, characterized in that: A cross section obtained by intersecting a virtual cylindrical surface concentric with the cylindrical surface of the hub (100) and the blade (200) is a profile of the blade (200), the number of the profiles is four, and the four profiles divide the trailing edge (240) from the blade root (210) to the blade tip (220) into a first edge area (251), a second edge area (252) and a third edge area (253).

12. The axial flow fan blade according to claim 11, characterized in that: The length of the first edge zone (251) is L1, the number of the saw teeth (300) in the first edge zone (251) is n1, and the tooth width w1 of the saw teeth (300) in the first edge zone (251) is in the range of (0.2 to 1)*L1 / n1; the length of the second edge zone (252) is L2, the number of the saw teeth (300) in the second edge zone (252) is n2, and the tooth width w2 of the saw teeth (300) in the second edge zone (252) is in the range of (0.5 to 1.5)*L2 / n2; the length of the third edge zone (253) is L3, the number of the saw teeth (300) in the third edge zone (253) is n3, and the tooth width w3 of the saw teeth (300) in the third edge zone (253) is in the range of (0.8 to 2)*L3 / n3.

13. The axial flow fan blade according to claim 12, characterized in that: The number n1 of the saw teeth (300) in the first edge area (251), the number n2 of the saw teeth (300) in the second edge area (252), and the number n3 of the saw teeth (300) in the third edge area (253) all range from 2 to 10.

14. The axial flow fan blade according to claim 11, characterized in that: The position of the first profile is (r-Ra) / (Rb-Ra)=12.5%, the position of the second profile is (r-Ra) / (Rb-Ra)=37.5%, the position of the third profile is (r-Ra) / (Rb-Ra)=62.5%, and the position of the fourth profile is (r-Ra) / (Rb-Ra)=87.5%, wherein Ra is the radius of the cylindrical surface of the hub (100), r is the radius of the cylindrical surface concentric with the cylindrical surface of the hub (100), and Rb is the radius of the cylindrical surface of the blade tip (220).

15. The axial flow fan blade according to claim 14, characterized in that: The blade (200) comprises a suction surface (260) and a pressure surface (270) facing away from the suction surface (260), and the suction surface (260) is provided with a plurality of recessed portions (261) having different recessed depths.

16. The axial flow fan blade according to claim 15, characterized in that: The recessed portions (261) are spaced apart from each other in a direction from the blade root (210) to the blade top (220), and the blades (200) are similar in shape. The edges of the recessed portions (261) are spaced apart from the leading edge (230), the trailing edge (240), the blade top (220), and the blade root (210).

17. The axial flow fan blade according to claim 15, characterized in that: The first recessed portion (261a) is within a first area defined by the first profile and the second profile, the second recessed portion (261b) is within a second area defined by the second profile and the third profile, and the third recessed portion (261c) is within a third area defined by the third profile and the fourth profile.

18. The axial flow fan blade according to claim 17, characterized in that: The average thickness of the blades (200) in the first region is H1, and the depression depth of the first depression (261a) ranges from 0.15H1 to 0.35H1; the average thickness of the blades (200) in the second region is H2, and the depression depth of the second depression (261b) ranges from 0.15H2 to 0.35H2; the average thickness of the blades (200) in the third region is H3, and the depression depth of the third depression (261c) ranges from 0.15H3 to 0.35H3.

19. The axial flow fan blade according to claim 14, characterized in that: The blade (200) has a suction surface (260) and a pressure surface (270) facing away from the suction surface (260); the blade (200) is provided with a bending portion (280) near the blade tip (220); the bending portion (280) is folded from the pressure surface (270) toward the suction surface (260).

20. The axial flow fan blade according to claim 19, characterized in that: The bent portion (280) is arranged in a fourth area defined by the fourth profile and the blade tip (220), and a bending angle of the bent portion (280) gradually increases and then gradually decreases in a direction from the leading edge (230) to the trailing edge (240).

21. The axial flow fan blade according to claim 20, characterized in that: A first section (J1), a second section (J2) and a third section (J3) are cut on the blade (200) in the direction from the blade root (210) to the blade top (220), wherein a bending angle of a first bending point (281) on the first section (J1) is smaller than a bending angle of a second bending point (282) on the second section (J2), and a bending angle of the second bending point (282) on the second section (J2) is larger than a bending angle of a third bending point (283) on the third section (J3).

22. The axial flow fan blade according to claim 1, characterized in that: The thickness of the blade (200) gradually decreases from the blade root (210) to the blade tip (220).

23. An axial flow fan, characterized in that: It comprises an axial flow fan blade and an air guide ring as described in any one of claims 1 to 22, wherein the axial flow fan blade is arranged in the air guide ring.

24. An air conditioner, characterized in that: Comprising the axial flow fan as claimed in claim 23.

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