Axial flow fan blades and axial flow fans

Abstract

The present invention relates to an axial flow fan blade and an axial flow fan, wherein the blade includes a blade body having a connecting end, an outer edge away from the connecting end, and a leading edge and a trailing edge correspondingly arranged on opposite sides of the outer edge. When installed, the blade body faces the air outlet area from the front, and a plurality of comb teeth are formed on the trailing edge that can effectively cut and comb large vortices into countless small vortices. The axial flow fan blade also includes a flow guide fold that bends from the outer edge to the back of the blade body. On the one hand, the present invention can avoid the generation of strong turbulence in the gap between the blade end and the wall ring, thereby reducing noise; on the other hand, it can effectively cut and comb large vortices into countless small vortices, and can also effectively separate the viscous airflow of the blade to form an ideal airflow, thereby achieving high efficiency and low noise.

Description

Technical Field

[0001] The present invention belongs to the field of fans, and in particular relates to an axial flow fan blade, and also relates to an axial flow fan having the blade. Background Art

[0002] Axial flow fans are widely used in air handling devices and various ventilation and heat dissipation environments due to their large air volume, low noise and low pressure. The design of axial flow fans has a great impact on the efficiency and noise of the fans. As the country improves the energy efficiency of air conditioners, the efficiency requirements for fans used for heat dissipation are also higher, requiring the wind wheel to have low noise and high efficiency.

[0003] However, in fans equipped with wall rings, the main source of noise is located at the radial outer edge of the blades. The specific reason is that there is a small gap between the end of the blade and the wall ring, and noise is generated in this area due to high turbulence. At the same time, the trailing edge of the blade can neither effectively cut and comb the large vortex generated at the outlet into countless small vortices, nor effectively separate the viscous airflow on the blades, and can not play a guiding role, and cannot form an ideal airflow, so the efficiency is low and the noise is high. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art and provide an improved axial flow fan blade.

[0005] At the same time, the present invention also provides an axial flow fan.

[0006] In order to solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0007] An axial flow fan blade includes a blade body, the blade body having a connecting end for connecting to a hub, an outer edge away from the connecting end, and a leading edge and a trailing edge correspondingly arranged on opposite sides of the outer edge. The blade body has a front side facing the air outlet direction and a back side corresponding to the front side, wherein a plurality of spaced-apart tooth grooves are formed by recessing from the trailing edge into the blade body, and a comb tooth is formed between each two adjacent tooth grooves. The comb teeth on the trailing edge can effectively cut and comb large vortices into small vortices. The axial flow fan blade also includes a guide fold bent from the outer edge to the back side of the blade body.

[0008] Preferably, the outer edge has a first end and a second end relatively close to and far away from the center of the hub, and the connecting end corresponds to the outer edge and forms a third end and a fourth end, wherein a trailing edge is formed between the first end and the third end, and a leading edge is formed between the second end and the fourth end.

[0009] According to the present invention, the outer edge, leading edge and trailing edge are all arc-shaped, and the corresponding radii are R, R1 and R2 respectively, wherein the outer edge protrudes from the first end and the second end toward the direction away from the connecting end, the leading edge protrudes from the second end and the fourth end toward the side where the trailing edge is located, and the trailing edge protrudes from the first end and the third end toward the direction away from the leading edge, and R1≤R2≤R.

[0010] Preferably, the connecting end protrudes from the third and fourth ends toward the leading edge and forms an arc shape with a radius of R3, where R3 ≤ R1 ≤ R2 ≤ R, and the third and fourth ends are rounded at their connection to the leading and trailing edges, respectively. The arc shape of the connecting end facilitates installation while also reducing drag and noise during the rounded transition.

[0011] According to another specific embodiment and preferred aspect of the present invention, the blade body is arched from the front to the back along the sides where the leading edge and the trailing edge are located, and the guide flanges are arched from both ends toward the back. In this way, the multiple comb teeth are arranged unevenly on the orthographic projection plane of the blade body in the thickness direction, thereby combing the stratified airflow, further improving the blade's efficiency and further reducing noise.

[0012] The arch is located in the middle of the blade body and the guide fold, and is in the shape of an arc with a radius of R4, where R≤R4≤2.6R. In this example, R4=2.2R. At this time, the air volume from the blade is large and the noise is small.

[0013] Preferably, the area of ​​each tooth groove is different. In this way, on the one hand, the large vortex generated at the air outlet is cut and combed into countless small vortices, and on the other hand, the viscous airflow of the blade is effectively separated. Therefore, it can not only reduce noise but also improve the cutting and combing effect of the blade.

[0014] Each tooth groove is V-shaped, with its tip facing inwards towards the rear edge; each comb tooth is also V-shaped, which makes it easier to process and shape the comb teeth.

[0015] According to another specific embodiment and preferred aspect of the present invention, the tooth pitch between each two adjacent comb teeth is γ, the tooth height of each comb tooth is H, and multiple arc segments are formed from the leading edge to the trailing edge, concentric with the outer edge, passing through the tooth tip of each comb tooth. The radius corresponding to the arc segment is r, and the chord length corresponding to the arc segment is x, where r / R∈[0.50-1.00], γ / H∈[1.00-1.60], and H / x∈[0.05-0.15]. Based on the above ratio information, the shape of the comb teeth and the position of the tooth tips can be determined.

[0016] Preferably, the relationship between the r / R value and the γ / H value satisfies the following formula: Y = -12.295X2 + 19.976X - 6.7155, where X corresponds to the r / R value and Y corresponds to the γ / H value. Under this relationship, the formed comb teeth can achieve the desired effect.

[0017] According to another specific embodiment and preferred aspect of the present invention, the guide edge has an inner folded surface facing the connection end and an outer folded surface opposite the inner folded surface. The outer folded surface has a rounded transition to the front of the blade body, and the angle A formed between the inner folded surface and the back of the blade body is obtuse. With such a large angle of guide, the particularly strong turbulence in the gap area is greatly reduced.

[0018] Preferably, the angle formed between the inner folded surface and the back surface of the blade body is gradually reduced from the front end of the outer edge to the rear end of the outer edge, thereby achieving the best diversion effect and reducing noise.

[0019] Furthermore, 120°≤∠A≤160°.

[0020] In addition, the width of the guide fold is gradually reduced from the front end of the outer edge to the rear end of the outer edge, thereby reducing wind resistance and improving airflow dispersion, thereby providing a larger air volume output while satisfying the turbulence suppression effect.

[0021] Preferably, the width of the fold formed by the guide fold is w, wherein R / 200≤w≤R / 100.

[0022] Specifically, the guide fold has a fifth end and a sixth end, and the guide fold is arc-shaped from the fifth end and the sixth end toward the side away from the connecting end, wherein the radius of the guide fold is equal to the radius of the outer edge.

[0023] Preferably, the fifth end is connected to the second end, and the sixth end is connected to the first end, wherein the fifth end is located on the side of the line connecting the second and fourth ends that is relatively far from the leading edge, and the fifth end of the guide edge, the second end of the outer edge, and the end of the leading edge away from the connecting end form the blade tip. The arrangement of the blade tip can reduce noise and improve efficiency on the one hand, and reduce wind resistance on the other hand, while also breaking up part of the airflow and avoiding turbulence.

[0024] Another technical solution of the present invention is: an axial flow fan, including a hub, blades and an air guide ring, the blades are the above-mentioned axial flow fan blades, and the axial flow fan blades have at least two pieces, wherein the two or more pieces are evenly distributed around the circumference of the hub, and the self-connecting end is connected to the hub, and the front of the axial flow fan blade faces the air outlet end of the air guide ring.

[0025] Due to the implementation of the above technical solution, the present invention has the following advantages compared with the prior art:

[0026] On the one hand, the present invention can avoid the generation of strong turbulence in the gap between the blade end and the wall ring, thereby reducing noise; on the other hand, it can effectively cut and comb large vortices into countless small vortices, and can also effectively separate the viscous airflow of the blade to form an ideal airflow. Therefore, it has high efficiency and low noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of the axial flow fan of the present invention;

[0028] Figure 2 This is a front structural schematic diagram of an axial flow fan blade of the present invention;

[0029] Figure 3 This is a schematic diagram of the back structure of the axial flow fan blade of the present invention;

[0030] Figure 4 Schematic diagram of comb tooth distribution of axial flow fan blades of the present invention;

[0031] Figure 5 4 is a schematic cross-sectional view in the AA direction;

[0032] Figure 6 The figure is a comparison curve diagram of the air volume and efficiency before and after the implementation of the blade;

[0033] Figure 7 The figure is a comparison curve diagram of the air volume and noise before and after the blade is implemented;

[0034] Among them: A, wheel hub;

[0035] B. Axial fan blades; 1. Blade body; a. Front; b. Back; 1a. Connecting end; 1b. Outer edge; 1c. Leading edge; 1d. Trailing edge; 1e. Comb teeth; 1e. Tooth grooves; 2. Guide fold;

[0036] C. Air guide ring;

[0037] Y, leaf tip. DETAILED DESCRIPTION

[0038] To make the above-mentioned objects, features, and advantages of the present application more clearly understood, the specific embodiments of the present application are described in detail below with reference to the accompanying drawings. The following description sets forth many specific details to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways than those described herein, and those skilled in the art can make similar improvements without violating the scope of the present application. Therefore, the present application is not limited to the specific embodiments disclosed below.

[0039] like Figure 1As shown, the axial flow fan of this embodiment includes a hub A, axial flow fan blades B and an air guide ring C, wherein the blades B have five pieces and are evenly distributed around the circumference of the hub A.

[0040] Specifically, the axial flow fan blade B includes a blade body 1 and a flow guide fold 2, wherein the blade body 1 and the flow guide fold 2 are integrally formed.

[0041] Combine Figure 2 and Figure 3 As shown, the blade body 1 has a front side a and a back side b. The blade body 1 also has a connecting end 1a, an outer edge 1b away from the connecting end 1a, and a leading edge 1c and a trailing edge 1d correspondingly arranged on opposite sides of the outer edge 1b. When installed, the blade body 1 faces the air guide ring C from the front side a, that is, the front side a faces the air outlet direction, and the back side b is the surface corresponding to the front side a.

[0042] Specifically, the outer edge 1b has a first end and a second end relatively close to and far away from the center of the hub A, and the connecting end 1a corresponds to the outer edge 1b and forms a third end and a fourth end, wherein a trailing edge 1d is formed between the first end and the third end, and a leading edge 1c is formed between the second end and the fourth end.

[0043] Combine Figure 4 As shown, in this example, the connecting end 1a, outer edge 1b, front edge 1c, and rear edge 1d are all arc-shaped, and the corresponding radii are R, R1, R2, and R3, respectively, where R3≤R1≤R2≤R.

[0044] Specifically, the connecting end 1a protrudes from the third end and the fourth end toward the side where the outer edge 1b is located; the outer edge 1b protrudes from the first end and the second end toward a direction away from the connecting end 1a, the leading edge 1c protrudes from the second end and the fourth end toward the side where the trailing edge 1d is located, and the trailing edge 1d protrudes from the first end and the third end toward a direction away from the leading edge 1c.

[0045] In this example, the blade body 1 is arched from the front side a to the back side b from the side where the leading edge 1c and the trailing edge 1d are located, and the guide fold 2 is bent from the outer edge 1b to the back side b to form a fifth end and a sixth end, wherein the fifth end is connected to the second end, and the sixth end is connected to the first end. In addition, the above-mentioned arc-shaped connecting end 1a, outer edge 1b, leading edge 1c, and trailing edge 1d are arranged to determine the shape of the blade.

[0046] Specifically, the guide fold 2 is in an arc shape from the fifth end and the sixth end toward the side away from the connecting end 1a, wherein the radius of the guide fold 2 is equal to that of the outer edge 1b.

[0047] At the same time, the fifth end is located on the side of the line connecting the second end and the fourth end relatively far from the leading edge 1c.

[0048] In this way, the fifth end of the guide flange 2, the second end of the outer edge 1b, and the end of the leading edge 1c away from the connecting end 1a form a blade tip Y, with the fifth end having a rounded transition. The blade tip reduces noise and improves efficiency while also reducing wind resistance and partially breaking up the airflow to avoid turbulence.

[0049] In this example, the circular arc design of the leading edge 1c reduces wind resistance and, in turn, noise. The circular arc design of the trailing edge 1 prevents the comb teeth from being aligned, thereby enhancing the effect of cutting and combing large vortices and preventing the formation of eddies. The circular arc design of the outer edge 1b further facilitates the formation of the blade tip, and the blade tip is the first part to come into contact with the airflow, making it less likely to obstruct the flow. The third and fourth ends have rounded transitions where they connect with the leading edge 1c and trailing edge 1d, respectively. The circular arc design of the connecting ends facilitates installation, while also reducing drag and noise during the rounded transition.

[0050] In this example, a plurality of comb teeth 1f are formed on the trailing edge 1d, which can effectively cut and comb the large vortex into numerous small vortices, wherein the plurality of comb teeth 1f are sequentially distributed between the first end and the third end.

[0051] Specifically, the arc-shaped side of the trailing edge 1d is recessed toward the leading edge 1c to form a plurality of spaced-apart groves 1e. Each adjacent grove 1e forms a comb tooth 1f, and the areas of each grove 1e vary. This not only cuts and combs the large vortex generated at the air outlet into numerous small vortices, but also effectively separates the viscous airflow of the blade, thereby reducing noise while improving the blade's ability to cut and comb the small vortices.

[0052] In this example, each tooth groove 1e is in a "V" shape, with its tip portion facing inwardly toward the rear edge 1d; and each comb tooth 1f is correspondingly in a "V" shape.

[0053] At the same time, the plurality of comb teeth 1f are arranged unevenly on the orthographic projection surface in the thickness direction of the blade body 1. In this way, the stratified airflow can be combed, the efficiency of the blade is further improved, and the noise is further reduced.

[0054] Specifically, the flow guide fold 2 has an outer fold surface 2a and an inner fold surface 2b. The outer fold surface 2a forms a circular arc transition with the front surface a of the blade body 1, and the inner fold surface 2b forms an obtuse angle with the back surface b of the blade body 1. With such a large flow guide angle, the particularly strong turbulence in the gap area is greatly reduced.

[0055] The angle formed between the inner folded surface 2b and the back surface b of the blade body 1 is gradually reduced from the second end to the first end, thereby achieving the best diversion effect and more obvious noise reduction effect.

[0056] In this example, the angle between the inner folded surface 2b where the second end is located and the back surface b of the blade body 1 is ∠α=156°, and the angle between the inner folded surface 2b where the first end is located and the back surface b of the blade body 1 is ∠β=132°. This not only reduces wind resistance but also disperses airflow and reduces noise.

[0057] In addition, the width of the guide fold 2 gradually decreases from the second end to the first end, thereby reducing wind resistance and improving airflow dispersion, thereby providing a larger air volume output while satisfying the turbulence suppression effect.

[0058] Specifically, the width of the guide fold 2 at the second end is R / 100, and the width of the guide fold 2 at the first end is R / 200.

[0059] In this example, there are 8 tooth grooves 1e, and every two adjacent tooth grooves 1e form a comb tooth 1f, where the tooth pitch between every two adjacent comb teeth is γ, the tooth height of each comb tooth is H, and multiple arc segments passing through the tooth tip of each comb tooth are formed from the leading edge to the trailing edge, which are concentric with the outer edge. The radius corresponding to the arc segment is r, and the chord length corresponding to the arc segment is x.

[0060] Specifically, taking the radius R=475 of the outer edge 1b as an example, the corresponding relationships among the above γ, H, r, and x are shown in the following table.

[0061]

[0062] At the same time, let X = r / R, Y = γ / H, and the values ​​of X and Y satisfy the following formula: Y = -12.295X 2 +19.976X-6.7155, that is, only the comb teeth designed to meet the above relationship can achieve the expected technical effect of this application.

[0063] Combine Figure 5 As shown, the arch is located in the middle of the blade body 1 and is in the shape of an arc with a radius of R4, wherein R4=2.2R, and the effect is best at this time.

[0064] In summary, this embodiment has the following advantages:

[0065] 1) The blade body, formed by the special arc shape and its edges, and the integrally formed guide fold, can, on the one hand, avoid strong turbulence in the gap between the blade end and the wall ring, thereby reducing noise; on the other hand, it can effectively cut and comb large vortices into countless small vortices, and can also effectively separate the viscous airflow of the blade to form an ideal airflow, thus achieving high efficiency and low noise;

[0066] 2) The multiple comb teeth are arranged unevenly in the thickness direction of the blade body. This can comb the stratified airflow, improve the efficiency of the blade, and further reduce noise;

[0067] 3) By setting the angle and width of the guide fold, not only can the wind resistance be reduced, but the working efficiency of the fan blades can also be improved while reducing noise.

[0068] In addition, combined with the Figure 6 and Figure 7 As shown, it can be intuitively seen that after the blade of the present application is used, its working efficiency is significantly improved under the same air volume, and the noise generated during operation is significantly reduced. At the same time, in this example, the size and gradual change of the angle formed by the guide fold and the back of the blade body, combined with the gradual change of the width formed by the guide fold, form an overall solution for the shape of the blade itself. The technical effects brought about by this can best achieve the advantages of low noise and high efficiency.

[0069] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the scope of protection of the present invention. Any equivalent changes or modifications made based on the spirit of the present invention should be included in the scope of protection of the present invention.

Claims

1. An axial flow fan blade, comprising a blade body, the blade body having a connecting end for connecting to a hub, an outer edge remote from the connecting end, and a leading edge and a trailing edge correspondingly disposed on opposite sides of the outer edge, the blade body having a front side facing the air outlet direction and a back side corresponding to the front side, characterized in that: A plurality of spaced-apart tooth grooves are formed from the trailing edge into the blade body, and a comb tooth is formed between each two adjacent tooth grooves. The comb teeth on the trailing edge can effectively cut and comb the large vortex into small vortices. The axial fan blade also includes a guide fold bent from the outer edge to the back of the blade body; each tooth groove is "V" shaped, the tooth pitch between each two adjacent comb teeth is γ, the tooth height of each comb tooth is H, and it is concentric with the outer edge and draws an arc from the leading edge to the trailing edge to form multiple lines passing through each comb tooth. The arc segment of the tooth tip, the radius of the arc segment is r, the chord length of the arc segment is x, where r / R∈[0.50~1.00],γ / H∈[1.00~1.60],H / x∈[0.05~0.15]; X=r / R, Y=γ / H, and the value of X and the corresponding Y satisfy the formula: Y=-12.295X2+19.976X-6.7155; the outer edge has a relatively close and far away from the hub center. The first end and the second end of the heart, the connecting end corresponds to the outer edge and forms a third end and a fourth end, wherein a trailing edge is formed between the first end and the third end, and a leading edge is formed between the second end and the fourth end, the outer edge and the leading edge are both arc-shaped, and the corresponding radii are R and R1 respectively, wherein the outer edge protrudes from the first end and the second end toward the direction away from the connecting end, and the leading edge protrudes from the second end and the fourth end toward the side where the trailing edge is located, and R1≤R; the guide fold has an inner fold surface facing the connecting end and an outer fold surface opposite to the inner fold surface, a rounded transition between the outer fold surface and the front side of the blade body, and an angle A is formed between the inner fold surface and the back side of the blade body, wherein the angle A is an obtuse angle, 120°≤∠A≤160°, and the fold width of the guide fold gradually decreases from the second end of the outer edge to the first end of the outer edge; the fold width formed by the guide fold is w, wherein R / 200≤w≤R / 100.

2. The axial flow fan blade according to claim 1, characterized in that: The trailing edge protrudes from the first end and the third end toward a direction away from the leading edge in an arc shape, wherein the radius of the arc is R2, and R1≤R2≤R.

3. The axial flow fan blade according to claim 2, characterized in that: The connecting end protrudes from the third end and the fourth end toward the side where the outer edge is located and is in an arc shape with a radius of R3, where R3≤R1≤R2≤R, and the third end and the fourth end are connected to the leading edge and the trailing edge respectively with rounded corners.

4. The axial flow fan blade according to claim 1, characterized in that: The blade body is arched from the front side to the back side from the side where the leading edge and the trailing edge are located, and the guide folds are arched from both ends toward the back side.

5. The axial flow fan blade according to claim 4, characterized in that: The arch is located in the middle of the blade body and the guide fold, and is in the shape of an arc with a radius of R4, wherein R≤R4≤2.6R.

6. The axial flow fan blade according to claim 1, characterized in that: The angle formed between the inner folding surface and the back surface of the blade body is gradually reduced from the second end portion to the first end portion.

7. The axial flow fan blade according to claim 1, characterized in that: The guide fold has a fifth end and a sixth end, and the guide fold is arc-shaped from the fifth end and the sixth end toward the side away from the connecting end, wherein the radius of the guide fold is equal to the radius of the outer edge.

8. The axial flow fan blade according to claim 7, characterized in that: The fifth end is connected to the second end, and the sixth end is connected to the first end, wherein the fifth end is located on the side of the line connecting the second end and the fourth end relatively away from the leading edge, and the fifth end of the guide fold, the second end of the outer edge, and the end of the leading edge away from the connecting end form a blade tip.

9. An axial flow fan comprising a hub, blades and an air guide ring, characterized in that: The blade is an axial flow fan blade according to any one of claims 1 to 8, and there are at least two axial flow fan blades, wherein two or more blades are evenly distributed around the circumference of the hub and are connected to the hub from the connecting end, and the front of the axial flow fan blade faces the air outlet end of the air guide ring.

Images