CN114151383A - Axial flow fan blade, axial flow fan and air conditioner - Google Patents

Abstract

The application relates to an axial fan blade, axial fan and air conditioner, an axial fan blade includes: a hub; blades arranged on the peripheral side of the hub; the blade is provided with a blade root, a blade top, a leading edge and a trailing edge, the blade root is connected to the peripheral side of the hub, and the leading edge and the trailing edge are oppositely connected between the blade top and the blade root; the rear edge is provided with a plurality of sawteeth, and the sawteeth are connected through arc sections; the rear edge is divided into a plurality of adjacent edge areas from the blade root to the blade top, the radians of the arc sections in the same edge area are equal, and the radians of the arc sections in different edge areas are gradually increased from the blade root to the blade top. An axial flow fan comprises the axial flow fan blade and an air guide ring, wherein the axial flow fan blade is arranged in the air guide ring. An air conditioner comprises the axial flow fan. The axial flow fan blade, the axial flow fan and the air conditioner weaken the trailing edge shedding vortex of the axial flow fan blade and can reduce aerodynamic noise.

Description

Axial flow fan blade, axial flow fan and air conditioner

Technical Field

The application relates to the technical field of fans, in particular to an axial flow fan blade, an axial flow fan and an air conditioner.

Background

At present, the axial flow fan is widely applied to various air treatment equipment, and the working efficiency and various performances of the axial flow fan have important influences on the capacity, the energy efficiency and the use comfort of the air treatment equipment.

Vortex separation is generated on the surface of the fan blade, is particularly obvious at the rear edge of the fan blade, and can cause random lift pulsation, meanwhile, the air flow along the radial direction is interfered, broadband vortex noise is easily generated, and therefore the performance of the fan blade is influenced.

Disclosure of Invention

Based on this, it is necessary to provide an axial flow fan blade, an axial flow fan and an air conditioner for reducing the noise of the trailing edge of the blade.

An axial flow fan blade comprising:

a hub;

blades arranged on the peripheral side of the hub; the blade is provided with a blade root, a blade top, a leading edge and a trailing edge, the blade root is connected to the peripheral side of the hub, and the leading edge and the trailing edge are oppositely connected between the blade top and the blade root;

the rear edge is provided with a plurality of sawteeth, and the sawteeth are connected through arc sections; the rear edge is divided into a plurality of adjacent edge areas from the blade root to the blade top, the radians of the arc sections in the same edge area are equal, and the radians of the arc sections in different edge areas are gradually increased from the blade root to the blade top.

The sawtooth structure arranged at the rear edge of the axial flow fan blade can effectively cut shedding vortexes generated by rotation, the number and scale of the shedding vortexes at the rear edge are reduced, and the aerodynamic noise of the fan blade can be reduced; the radian of the arc sections of the sawteeth in different edge areas is gradually increased from the blade root to the blade top, so that the air quantity of the axial flow fan blade during rotation is ensured while the trailing edge shedding vortex is weakened.

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 arranged at an included angle, the arc segment is connected to an 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 end points of the first straight line segment and the second straight line segment is the tooth width w of the saw tooth.

In one embodiment, each of the saw teeth further comprises a connecting section, and the first straight line segment and the second straight line segment are connected through the connecting section.

In one embodiment, the radian of each connecting section in the same edge region is equal, and the radians of the connecting sections in different edge regions are gradually increased from the blade root to the blade tip.

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

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 are linearly changed or equal.

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

In one embodiment, the chord length of the blade is L, the tooth height h of the saw tooth ranges from 0.05L to 0.15L, and the arc length L of the arc section ranges from 0.1h to 0.15 h.

In one embodiment, the thickness of the saw teeth is gradually reduced from the front edge to the rear edge.

In one embodiment, the thickness of the saw teeth is gradually reduced from the blade root to the blade tip.

In one embodiment, a section obtained by intersecting a cylindrical surface concentric with the cylindrical surface of the hub and the blade is a profile of the blade, the number of the profiles is four, and the four profiles divide the trailing edge into three edge regions from the blade root to the blade tip.

In one embodiment, the length of the first edge region is L1, the number of the saw teeth of the first edge region is n1, and the tooth width w1 of the saw teeth of the first edge region ranges from (0.2 to 1) × L1/n 1; the length of the second edge region is L2, the number of the sawteeth of the second edge region is n2, and the tooth width w2 of the sawteeth of the second edge region ranges from (0.5-1.5) × L2/n 2; the length of the third edge region is L3, the number of the saw teeth of the third edge region is n3, and the tooth width w3 of the saw teeth of the third edge region ranges from (0.8-2) × L3/n 3.

In one embodiment, the number of the sawteeth n1, n2 and n3 is 2-10.

In one embodiment, the first profile is located at 12.5% (r-Ra)/(Rb-Ra), the second profile is located at 37.5% (r-Ra)/(Rb-Ra), the third profile is located at 62.5% (r-Ra)/(Rb-Ra), and the fourth profile is located at 87.5% (r-Ra)/(Rb-Ra), wherein r is the radius of the cylindrical surface of the hub, Ra is the radius of the virtual cylindrical surface concentric with the cylindrical surface of the hub, and Rb is the radius of the apical cylindrical surface.

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 recesses with different recess depths.

In one embodiment, the recessed portions are spaced side by side in a direction from the blade root to the blade tip, the blade shapes are similar, and the edges of the recessed portions are spaced from the leading edge, the trailing edge, the blade tip and the blade root.

In one embodiment, the first recess is in a first region defined by the first and second profiles, the second recess is in a second region defined by the second and third profiles, and the third recess is in a second region defined by the third and fourth profiles.

In one embodiment, the average thickness of the blades in the first region is H1, and the recess depth of the first recess ranges from 0.15H1 to 0.35H 1; the average thickness of the blades in the second region is H2, and the depression depth range of the second depression part is 0.15H 2-0.35H 2; the average thickness of the blades in the third area is H3, and the depression depth range of the third depression part is 0.15H 3-0.35H 3.

In one embodiment, the blade is provided with a suction surface and a pressure surface departing from the suction surface, a bent part is arranged at a position, close to the blade top, of the blade, and the bent part is turned over from the pressure surface to the direction of the suction surface.

In one embodiment, the bending portion is disposed in a fourth region 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.

In one embodiment, a first section, a second section and a third section are taken from the blade root to the blade tip in the direction of the blade tip, 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.

In one embodiment, the blade thickness decreases from the blade root to the blade tip.

An axial flow fan comprises the axial flow fan blade and an air guide ring, wherein the axial flow fan blade is arranged in the air guide ring.

The axial flow fan weakens the trailing edge shedding vortex of the axial flow fan blade and can reduce the pneumatic noise of the fan blade.

An air conditioner comprises the axial flow fan.

The air conditioner weakens the vortex shedding at the rear edge of the axial flow fan blade, and can reduce the pneumatic noise of the axial flow fan.

Drawings

FIG. 1 is a first schematic view of an axial-flow fan blade according to an embodiment;

FIG. 2 is a second schematic view of the axial-flow fan blade shown in FIG. 1;

FIG. 3 is a schematic view of a middle edge region of the axial-flow fan blade shown in FIG. 1;

FIG. 4 is a schematic view of serrations in the blade shown in FIG. 3;

FIG. 5 is a schematic view of a profile in the blade of FIG. 4;

FIG. 6 is a schematic view of a blade bending portion in the axial-flow fan blade shown in FIG. 1;

FIG. 7 is a schematic view of a blade in the axial flow fan of FIG. 1;

FIG. 8 is a cross-sectional view of a first cross-section of the blade shown in FIG. 7;

FIG. 9 is a cross-sectional view of a second cross-section of the blade shown in FIG. 7;

FIG. 10 is a cross-sectional view of a third cross-section of the blade shown in FIG. 7.

Fig. 11 is a schematic diagram showing the linear variation of the chord length L of the blade and the height percentage of the blade.

Reference numerals:

100. a hub; 200. a blade; 210. a blade root; 220. leaf tops; 230. a leading edge; 240. a trailing edge; 250. an edge region; 251. a first edge region; 252. a second edge region; 253. a third edge region; 260. A suction surface; 261. a recessed portion; 261a, a first recess; 261b, a second recess; 261c, a third recess; 270. a pressure surface; 280. a bending part; 281. a first bend; 282. a second bend; 283. a third bend; 300. saw teeth; 301. a circular arc section; 302. a first straight line segment; 303. a second straight line segment; 304. a connecting section; s1, a first molded surface; s2, a second molded surface; s3, a third molded surface; s4, a fourth molded surface; a1, a first area; a2, second area; a3, third area; a4, fourth area; theta, the inclination angle of the saw teeth; w, the tooth width of the saw teeth; h. the tooth height of the saw teeth; d. the tooth thickness of the saw teeth.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.

In the description of the present application, it is to be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," "circumferential," and the like are used in the orientations and positional relationships indicated in the drawings for convenience in describing the present application and for simplicity in description, and are not intended to indicate or imply that the referenced devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and are therefore not to be considered limiting of the present application.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.

In this application, unless expressly stated or limited otherwise, the terms "initially", "connected", "secured", and the like are to be construed broadly and can include, for example, fixed connections, removable connections, or integral parts; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art as appropriate.

In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may be directly contacting the first and second features or indirectly contacting the first and second features through intervening media. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.

It will be understood that when an element is referred to as being "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

Referring to fig. 1, an axial-flow fan blade in an embodiment includes a hub 100 and blades 200, and the blades 200 are disposed on a peripheral side of the hub 100. Blade 200 has a blade root 210, a blade tip 220, a leading edge 230 and a trailing edge 240, blade root 210 is connected to the peripheral side of hub 100, and leading edge 230 and trailing edge 240 are oppositely connected between blade tip 220 and blade root 210.

As shown in fig. 2, the rear edge 240 is provided with a plurality of saw teeth 300, and the saw teeth 300 are connected by an arc segment 301; referring to fig. 3, the trailing edge 240 is divided into a plurality of adjacent edge areas 250 from the blade root 210 to the blade tip 220, the radians of the arc sections 301 in the same edge area 250 are equal, and the radians of the arc sections 301 in different edge areas 250 are gradually increased from the blade root 210 to the blade tip 220.

It should be noted that, during the rotation of the blade 200, a vortex is generated on the surface of the blade 200 to separate, which causes random lift pulsation and causes interference of radial air flow, and broadband vortex noise is easily generated, thereby affecting the performance of the fan blade. Since the airflow flows from the leading edge 230 to the trailing edge 240, strong periodic shedding vortices are easily generated particularly at the trailing edge 240 of the blade 200, increasing kinetic energy loss.

Through the arrangement, the sawtooth 300 structure arranged on the rear edge 240 can effectively cut falling vortexes generated by rotation, the number and scale of the falling vortexes of the rear edge 240 are reduced, and aerodynamic noise of the fan blade can be reduced; the radian of the arc segment 301 of the sawtooth 300 in different edge regions 250 is gradually increased from the blade root 210 to the blade top 220, so that the air volume of the axial flow fan blade during rotation is ensured while the falling vortex of the trailing edge 240 is weakened.

In the embodiment shown in fig. 2, each sawtooth 300 includes a first straight line segment 302, a second straight line segment 303 and a circular arc segment 301, and the first straight line segment 302 and the second straight line segment 303 are arranged at an included angle.

In this embodiment, as shown in fig. 2, each sawtooth 300 further comprises a connecting section 304, and the first straight section 302 and the second straight section 303 are connected by the connecting section 304.

It is understood 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 sawteeth 300 are connected through a circular arc segment 301, that is, the end of a first straight line segment 302 of one sawtooth 300 is connected with the circular arc segment 301 of another adjacent sawtooth 300.

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

In the embodiment shown in fig. 2, the connecting section 304 has a circular arc shape. In other embodiments, the connecting section 304 may also be straight or otherwise shaped.

In the embodiment shown in fig. 2, the connecting sections 304 in the same edge region 250 have the same curvature, and the curvature of the connecting sections 304 in different edge regions 250 gradually increases from the blade root 210 to the blade tip 220.

Through the arrangement, the air quantity of the axial flow fan blade during rotation is ensured while the vortex shedding of the rear edge 240 is further weakened.

In this embodiment, and as shown in FIG. 4, the tip of each sawtooth 300 is located on the curve fitted to the trailing edge 240, and the angle between the first straight line segment 302 and the tangent Q of the curve fitted to the trailing edge 240 is the inclination angle θ of the sawtooth. 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, and the length of the second straight line segment 303 is the tooth height h of the sawtooth.

In the present embodiment, the inclination angle θ of each of the saw teeth, the width w of the saw teeth, and the height h of the saw teeth in the same edge region 250 may be linearly changed. Alternatively, the inclination angle θ of each of the saw teeth, the tooth width w of the saw teeth, and the tooth height h of the saw teeth in the same edge region 250 may be equal.

In other embodiments, the inclination angle θ of each sawtooth in the same edge region 250, the width w of the sawtooth, and the height h of the sawtooth may be designed according to actual use requirements.

In the present embodiment, as shown in fig. 4, the inclination angle θ of the serrations ranges from 25 degrees to 60 degrees. With this arrangement, each serration 300 can be made to effectively cut the trailing edge 240 off the vortex.

In this embodiment, as shown in fig. 2 and 4, the chord length of the blade 200 is L, the tooth height h of the saw tooth ranges from 0.05L to 0.15L, and the arc length L of the arc segment 301 ranges from 0.1h to 0.15 h. Through this setting, can make the smooth transition of junction through circular arc section 301 between each sawtooth 300, and effectively cut trailing edge 240 and drop the vortex.

It should be noted that, as shown in fig. 2, the blade 200 has a suction surface 260 and a pressure surface 270 facing away from the suction surface 260, and the height from the suction surface 260 to the pressure surface 270 is the thickness of the blade 200, i.e., the tooth thickness d of the serrations.

In the present embodiment, the chord length L of the blade 200 changes linearly.

For example, the chord length of the blade 200 increases linearly with increasing blade height percentage, which is defined as (r-Ra)/(Rb-Ra). Referring to fig. 5, 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.

When the values of (r-Ra)/(Rb-Ra) are 0%, 12.5%, 25%, 37.5%, 50%, 62.5%, 75%, 87.5% and 100%, respectively, the chord length of the corresponding vane 200 increases linearly, as shown in FIG. 11.

In one embodiment, as shown in FIG. 2, the tooth thickness d of the serrations decreases from the leading edge 230 to the trailing edge 240. Through the arrangement, on the premise of ensuring the performance and the structural reliability of the fan blade, the effects of reducing the weight of the fan blade and reducing the load are achieved.

In another embodiment, as shown in FIG. 2, the tooth thickness d of the serrations tapers from the leading edge 230 to the trailing edge 240, and the tooth thickness d of the serrations tapers from the root 210 to the tip 220.

In this embodiment, the thickness of the blade 200 is gradually reduced from the blade root 210 to the blade tip 220, so that the tooth thickness d of the saw tooth is gradually reduced from the blade root 210 to the blade tip 220. In other embodiments, only the portion of the blade 200 where the serrations 300 are provided may be gradually reduced in thickness from the blade root 210 to the blade tip 220, and the thickness of the portion of the blade 200 where the serrations 300 are not provided may be equal.

In the embodiment shown in fig. 3, the cross section of the cylindrical surface concentric with the cylindrical surface of the hub 100 intersecting the blade 200 is the profile of the blade 200. The number of profiles is four and the four profiles divide the trailing edge 240 into three edge regions 250 from the blade root 210 to the blade tip 220.

Specifically, as shown in fig. 3, the first profile S1 is located at 12.5% (r-Ra)/(Rb-Ra), the second profile S2 is located at 37.5% (r-Ra)/(Rb-Ra), the third profile S3 is located at 62.5% (r-Ra)/(Rb-Ra), the fourth profile S4 is located at 87.5% (r-Ra)/(Rb-Ra),

in other embodiments, the number of the profiles can be other values, and the number and the positions of the profiles can be set according to actual use requirements. For example, the number of profiles may be five, five profiles dividing the trailing edge 240 into four edge regions 250 in the direction from the root 210 to the tip 220.

In this embodiment, as shown in fig. 3, the length of the first edge zone 251 is L1, the number of the saw teeth 300 of the first edge zone 251 is n1, and the tooth width w1 of the saw teeth of the first edge zone 251 is (0.2-1) × L1/n 1; the length of the second edge region 252 is L2, the number of the saw teeth 300 of the second edge region 252 is n2, and the tooth width w2 of the saw teeth of the second edge region 252 ranges from (0.5 to 1.5) × L2/n 2; the length of the third edge region 253 is L3, the number of the saw teeth 300 of the third edge region 253 is n3, and the tooth width w3 of the saw teeth of the third edge region 253 ranges from (0.8-2) × L3/n 3.

It should be noted that, as shown in fig. 3, 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.

In this embodiment, as shown in fig. 3, the number n1 of the sawteeth 300 of the first edge region 251, the number n2 of the sawteeth 300 of the second edge region 252, and the number n3 of the sawteeth 300 of the third edge region 253 all range from 2 to 10.

In the present embodiment, the length of the first edge region 251, the length of the second edge region 252, and the length of the third edge region 253 are not equal. In other embodiments, the length of the first edge region 251, the length of the second edge region 252, and the length of the third edge region 253 may also all be equal.

In the present embodiment, the number n1 of the saw teeth 300 of the first edge region 251, the number n2 of the saw teeth 300 of the second edge region 252, and the number n3 of the saw teeth 300 of the third edge region 253 are different. In other embodiments, the number n1 of serrations 300 of the first edge region 251, the number n2 of serrations 300 of the second edge region 252, and the number n3 of serrations 300 of the third edge region 253 may be equal.

In the embodiment shown in fig. 3, the suction surface 260 is provided with a plurality of depressions 261 having different depression depths.

With this arrangement, the recessed portion 261 can suppress the development of the vortex generated at the surface of the blade 200 during the rotation of the blade 200, reducing the disturbance occurring in the radial air flow to attenuate the broadband vortex noise generated. Meanwhile, the structural reliability of the fan blade is ensured, and the weight of the fan blade is further reduced.

Note that, as shown in fig. 2, the concave portion 261 is formed by the suction surface 260 being concave downward toward the pressure surface 270.

In this embodiment, as shown in fig. 2, the recesses 261 are spaced side by side in a direction from the blade root 210 to the blade tip 220, and an edge of each recess 261 is spaced apart from the leading edge 230, the trailing edge 240, the blade tip 220, and the blade root 210.

In a particular embodiment, the edge of the depression 261 is spaced from the leading edge 230 by 0.15L to 0.2L, the edge of the depression 261 is spaced from the trailing edge 240 by 0.15L to 0.2L, the edge of the depression 261 is spaced from the tip 220 by 0.08L to 0.15L, and the edge of the depression 261 is spaced from the tip 220 by 0.125L to 0.175L.

As in the embodiment shown in fig. 5, the number of the recesses 261 is three. The first depression 261a is within a first region a1 defined by the first and second profiles S1 and S2, the second depression 261b is within a second region a2 defined by the second and third profiles S2 and S3, and the third depression 261c is within a third region A3 defined by the third and fourth profiles S3 and S4.

Specifically, as shown in fig. 2, the average thickness of the blade 200 in the first region a1 is H1, and the depression depth of the first depression 261a ranges from 0.15H1 to 0.35H 1; the average thickness of the blades 200 in the second area A2 is H2, and the depression depth range of the second depression part 261b is 0.15H 2-0.35H 2; the average thickness of the blades 200 in the third region a3 is H3, and the depression depth of the third depression 261c ranges from 0.15H3 to 0.35H 3.

In the present embodiment, the average thickness of the blades 200 in the first region a1 is H1, the average thickness of the blades 200 in the second region a2 is H2, and the average thickness of the blades 200 in the third region A3 is H3, which decrease in order, and the depression depth of the first depression 261a, the depression depth of the second depression 261b, and the depression depth of the third depression 261c increase in order. By this arrangement, it is possible to have a better attenuation effect on vortex shedding that may be generated on the surface of the blade 200.

In other embodiments, the average thickness of the blades 200 in the first region a1 may be equal to H1, the average thickness of the blades 200 in the second region a2 may be equal to H2, and the average thickness of the blades 200 in the third region A3 may be equal to H3, and the depression depth of the first depression 261a, the depression depth of the second depression 261b, and the depression depth of the third depression 261c may be equal to each other.

In the present embodiment, as shown in fig. 5, the first, second, and third recesses 261a, 261b, 261c are each shaped like the blade 200, and the edge of each recess 261 is spaced apart from the leading edge 230, trailing edge 240, tip 220, and root 210. With this arrangement, the recessed area of the recess 261 is enlarged as much as possible in a limited space to have a better attenuating effect on vortex shedding that may be generated on the surface of the blade 200.

In other embodiments, the recesses 261 may be arranged in a circular, rectangular, or other pattern. The shape of each depression 261 may also be circular or other irregular shape.

During rotation of the blade 200, due to the clearance of the blade tip 220, a portion of the fluid on the suction surface 260 may flow toward the pressure surface 270 under the pressure differential, thereby generating leakage vortex on the blade tip 220, increasing kinetic energy loss and noise. In view of the above, as shown in fig. 6, the blade 200 is provided with a bent portion 280 near the blade tip 220, and the bent portion 280 is bent from the pressure surface 270 toward the suction surface 260.

Through the setting, effectively reduce the blade top 220 air current leakage rate, reduce blade top 220 and leak the flow pulsation near whirlpool and blade top 220 to improve fan efficiency, reduce the aerodynamic noise of low-frequency range.

In the embodiment shown in fig. 5 and 6, the bend 280 is disposed in a fourth region a4 defined by the fourth profile S4 and the tip 220.

Specifically, as shown in fig. 1, the bending portion 280 extends from the front edge 230 to the rear edge 240, and the bending angle changes from small to large and then decreases from the front edge 230 to the rear edge 240.

It should be understood that, referring to fig. 7, the first cross section J1, the second cross section J2 and the third cross section J3 are cut from the blade root 210 to the blade tip 220 of the blade 200, fig. 8 is a schematic cross section of the first cross section J1, fig. 9 is a schematic cross section of the second cross section J1, and fig. 10 is a schematic cross section of the first cross section J1. The bending angle of the first bending 281 on the first section J1 is smaller than that of the second bending 282 on the second section J2, and the bending angle of the second bending 282 on the second section J2 is larger than that of the third bending 283 on the third section J3.

In the present embodiment, the number of the blades 200 is at least two, and each of the blades 200 is uniformly distributed around the circumferential direction of the hub 100.

Referring to fig. 1, an axial flow fan in an embodiment includes an air guiding ring and the axial flow fan blade described above, and the axial flow fan blade is disposed in the air guiding ring.

In a specific embodiment, the suction surface 260 of the blade 200 faces the air inlet end of the air guide ring, and the pressure surface 270 of the blade 200 faces the air outlet end of the air guide ring.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims (24)

1. An axial flow fan blade, comprising:

a hub (100);

a blade (200) provided on the circumferential side of the hub (100); the blade (200) is provided with a blade root (210), a blade top (220), a leading edge (230) and a trailing edge (240), the blade root (210) is connected to the peripheral side of the hub (100), and the leading edge (230) and the trailing edge (240) are oppositely connected between the blade top (220) and the blade root (210);

the rear edge (240) is provided with a plurality of sawteeth (300), and the sawteeth (300) are connected through arc sections (301); the trailing edge (240) is divided into a plurality of adjacent edge areas (250) from the blade root (210) to the blade top (220), the radians of the arc sections (301) in the same edge area (250) are equal, and the radians of the arc sections (301) in different edge areas (250) are gradually increased from the blade root (210) to the blade top (220).

2. The axial-flow fan blade as claimed in claim 1, wherein each of the saw teeth (300) includes a first straight line segment (302), a second straight line segment (303) and an arc segment (301), the first straight line segment (302) and the second straight line segment (303) are arranged at an included angle, the arc segment (301) is connected to an end of the second straight line segment (303), the length of the second straight line segment (303) is a tooth height h of the saw tooth (300), and an end point distance between the first straight line segment (302) and the second straight line segment (303) is a tooth width w of the saw tooth (300).

3. The axial-flow fan blade according to claim 2, characterized in that each said sawtooth (300) further comprises a connecting section (304), said first straight section (302) and said second straight section (303) being connected by said connecting section (304).

4. The axial-flow fan blade according to claim 3, wherein the radian of each connecting section (304) in the same edge region (250) is equal, and the radian of each connecting section (304) in different edge regions (250) is gradually increased from the blade root (210) to the blade tip (220).

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

6. The axial-flow fan blade according to claim 5, wherein the inclination angle θ of each sawtooth (300), the tooth width w of the sawtooth (300) and the tooth height h of the sawtooth (300) in the same edge region (250) are linearly changed or equal.

7. The axial-flow fan blade according to claim 5, wherein the inclination angle θ of the sawteeth (300) ranges from 25 degrees to 60 degrees.

8. The axial-flow fan blade according to claim 2, wherein the chord length of the blade (200) is L, the tooth height h of the saw tooth (300) ranges from 0.05L to 0.15L, and the arc length L of the arc section (301) ranges from 0.1h to 0.15 h.

9. The axial-flow fan blade according to claim 1, wherein the thickness of the teeth (300) is gradually reduced from the leading edge (230) to the trailing edge (240).

10. The axial-flow fan blade according to claim 1 or 9, wherein the thickness of the teeth (300) decreases from the blade root (210) to the blade tip (220).

11. The axial-flow fan blade according to claim 1, wherein a 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) into three edge regions (250) from the blade root (210) to the blade tip (220).

12. The axial-flow fan blade according to claim 11, wherein the length of the first edge zone (251) is L1, the number of the saw teeth (300) of the first edge zone (251) is n1, and the tooth width w1 of the saw teeth (300) of the first edge zone (251) is in the range of (0.2-1) × L1/n 1; the length of the second edge region (252) is L2, the number of the sawteeth (300) of the second edge region (252) is n2, and the tooth width w2 of the sawteeth (300) of the second edge region (252) ranges from (0.5-1.5) × L2/n 2; the length of the third edge region (253) is L3, the number of the saw teeth (300) of the third edge region (253) is n3, and the tooth width w3 of the saw teeth (300) of the third edge region (253) is in the range of (0.8-2) × L3/n 3.

13. The axial-flow fan blade according to claim 12, wherein the number n1 of the saw teeth (300) of the first edge zone (251) (250), the number n2 of the saw teeth (300) of the second edge zone (252), and the number n3 of the saw teeth (300) of the third edge zone (253) all have a value range of 2-10.

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

15. The axial-flow fan blade according to claim 14, wherein the blade (200) has 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 recesses (261) having different recess depths.

16. The axial-flow fan blade according to claim 15, wherein each of the recesses (261) is spaced side by side in a direction from the blade root (210) to the blade tip (220) and the blades (200) have similar shapes, and the edge of the recess (261) is spaced from the leading edge (230), the trailing edge (240), the blade tip (220) and the blade root (210).

17. The axial fan blade according to claim 15, wherein a first recess (261a) is in a first region defined by said first and second profiles, a second recess (261b) is in a second region defined by said second and third profiles, and a third recess (261c) is in a second region defined by said third and fourth profiles.

18. The axial-flow fan blade according to claim 17, wherein the average thickness of the blade (200) in the first region is H1, and the depression depth of the first depression (261a) is in the range of 0.15H 1-0.35H 1; the average thickness of the blades (200) in the second area is H2, and the depression depth of the second depression part (261b) ranges from 0.15H2 to 0.35H 2; the average thickness of the blades (200) in the third area is H3, and the depression depth range of the third depression part (261c) is 0.15H 3-0.35H 3.

19. The axial-flow fan blade according to claim 14, wherein the blade (200) has a suction surface (260) and a pressure surface (270) facing away from the suction surface (260), a bent portion (280) is provided at a position of the blade (200) close to the blade tip (220), and the bent portion (280) is bent from the pressure surface (270) to the direction of the suction surface (260).

20. The axial fan blade according to claim 19, wherein the bending portion (280) is disposed in a fourth area defined by the fourth profile and the blade tip (220), and the bending angle is gradually increased and then gradually decreased from the leading edge (230) to the trailing edge (240).

21. The axial fan blade according to claim 20, wherein a first cross section (J1), a second cross section (J2) and a third cross section (J3) are taken through the blade (200) from the blade root (210) to the blade tip (220), the bending angle of the first bend (281) on the first cross section (J1) is smaller than the bending angle of the second bend (282) on the second cross section (J2), and the bending angle of the second bend (282) on the second cross section (J2) is larger than the bending angle of the third bend (283) on the third cross section (J3).

22. The axial-flow fan blade according to claim 1, wherein the thickness of the blade (200) is gradually reduced from the blade root (210) to the blade tip (220).

23. An axial flow fan is characterized by comprising the axial flow fan blade and an air guide ring as claimed 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 by comprising the axial flow fan according to claim 23.

Images