CN215521368U - Impeller for centrifugal fan and centrifugal fan applying impeller - Google Patents

Abstract

The utility model relates to an impeller for a centrifugal fan and the centrifugal fan using the same, comprising: a front plate; a rear disc disposed opposite to the front disc; the blades are arranged between the front disc and the rear disc and are distributed at intervals along the circumferential direction of the front disc, each blade is provided with a first side edge corresponding to one side where airflow flows in and a second side edge corresponding to one side where the airflow flows out, and at least one of the first side edge and the second side edge is provided with a wavy edge; the blades comprise a first blade and a second blade which are arranged at intervals along the circumferential direction of the impeller, and the wavy edge of the first blade and the wavy edge of the second blade are of complementary structures, namely the wavy edges of the first blade and the second blade can be matched together in a flattened state. The impeller with the blades can effectively offset vortexes generated when airflow flows through the wavy edges of the air inlet side or the air outlet side of the two adjacent blades, so that the uniformity of airflow flowing on the air inlet side or the air outlet side of the impeller is improved, and effective noise reduction is realized.

Description

Impeller for centrifugal fan and centrifugal fan applying impeller

Technical Field

The utility model relates to the technical field of centrifugal fans, in particular to an impeller for a centrifugal fan and a centrifugal fan applying the impeller.

Background

Centrifugal fans are widely used, and impellers are important components of centrifugal fans. The rotation of impeller drives the gas flow, and whether its structural setting rationally directly influences the wholeness ability of fan, and especially the structural style of the exit of the blade of impeller has great influence to centrifugal fan's aerodynamic noise.

In order to reduce the above aerodynamic noise, at least one of a pair of side edges of each blade constituting the impeller is formed into a wavy edge to prevent the separation of the air flow on the negative pressure surface side of the blade and to reduce the generation of the trailing edge vortex on the trailing edge side of the blade, as disclosed in "an impeller for a centrifugal fan" of application No. 201310639469.5 (publication No. CN103696985A), the impeller includes a front ring and a rear ring, a plurality of blades are fixed between the front ring and the rear ring, the outlet end of the blade is formed into a wavy zigzag shape by a plurality of serrations, the position where the trailing edge vortex of the blade falls off is changed, the distance between the vortex centers is increased, the disturbance of the falling vortex to the trailing flow is suppressed, and further, the aerodynamic noise caused by the unsteady pressure pulsation of the blade surface and the trailing vortex is reduced. As disclosed in the chinese patent application with an application number of 201110432234.X (with an authorization publication number of CN102536892U), "a multi-blade centrifugal fan with enhanced air intake function", the centrifugal fan has a concave, convex, concave-convex combination, or inclined plane shape of the air intake edge of the blade, and the air exhaust edge of the blade is formed by a straight line, a curved line, a broken line, or a combination of a curved line and a straight line.

Although the impeller of the conventional centrifugal fan can reduce fan noise to a certain extent by arranging the wavy structure on the side edge of the air outlet or the side edge of the air inlet of the blade, the impeller still has certain defects, firstly, under the influence of the conventional processing mode, the wavy structure on the side of the air outlet or the side of the air inlet of the adjacent blade on the impeller cannot ensure the consistency of the wavy structure, namely the shapes and the sizes of the wavy bulges and the wavy recesses of the two adjacent blades are different, so that vortexes generated when airflow flows through the wavy edges on the side of the air inlet or the side of the air outlet of the two adjacent blades cannot be effectively resisted and eliminated, the flowing uniformity of the inlet airflow and the outlet airflow of the impeller is influenced, and effective noise reduction cannot be realized; secondly, in the process of processing the wavy edge of the blade, the side edge part of each corresponding blade blank is usually punched (cut), and the punched part becomes waste. Finally, the existing blade with the tail wing has inconsistent distances for obtaining energy on the blade because the width of the blade is changed along the axis and is not in an equal-width structural design, so that the maximum static pressure of the fan is reduced, and the overall aerodynamic performance of the centrifugal fan is influenced.

SUMMERY OF THE UTILITY MODEL

The first technical problem to be solved by the present invention is to provide an impeller for a centrifugal fan, which can effectively cancel out a vortex generated when an airflow flows through wavy edges on the air inlet side or the air outlet side of two adjacent blades, so as to improve the uniformity of the airflow flow on the air inlet side or the air outlet side of the impeller and realize effective noise reduction.

The second technical problem to be solved by the utility model is to provide an impeller for a centrifugal fan, which can effectively simplify the processing process and avoid the problem of material waste in the processing process, aiming at the current situation of the prior art.

The third technical problem to be solved by the present invention is to provide an impeller for a centrifugal fan, which can maintain a high static pressure, in view of the current situation of the prior art.

The fourth technical problem to be solved by the present invention is to provide a centrifugal fan using the above impeller in view of the current situation of the prior art.

The technical solution adopted by the present invention to solve any one of the first technical problem and the second technical problem is as follows: an impeller for a centrifugal fan, comprising:

a front plate;

a rear disc disposed opposite to the front disc;

the blades are arranged between the front disc and the rear disc and are distributed at intervals along the circumferential direction of the front disc, the blades are provided with a first side edge corresponding to one side where airflow flows in and a second side edge corresponding to one side where the airflow flows out, and at least one of the first side edge and the second side edge is provided with a wavy edge which periodically changes along the axis of the impeller;

the blades comprise a first blade and a second blade which are arranged at intervals in the circumferential direction of the impeller, and the wavy edge of the first blade and the wavy edge of the second blade are in a complementary structure.

As a preferred embodiment, in order to better reduce aerodynamic noise, the first side and the second side of the blade have the wavy edge.

The technical scheme adopted by the utility model for solving the third technical problem is as follows: the wave edge of first blade is including setting up and continuous first outer convex part and the first interior concave part in turn, the wave edge of second blade is including setting up and continuous second outer convex part and the interior concave part of second in turn, first outer convex part on the first side of first blade, first interior concave part respectively with the first interior concave part on the second side of this blade, first outer convex part just to setting up on the horizontal of this blade, so that first blade is the same at the width of wave edge, the second outer convex part on the first side of second blade, the interior concave part of second respectively with the second interior concave part on the second side of this blade, the outer convex part of second just to setting up on the horizontal of this blade, so that the width of second blade in wave edge is the same. The design of the equal-width blades can ensure that the blades keep the same width along the length direction of the impeller, reduce the noise of the flow separation and simultaneously keep higher static pressure, and improve the starting performance of the centrifugal fan.

As an improvement, a first outer convex part and a first inner concave part on the first side edge of the first blade are respectively arranged opposite to a second inner concave part and a second outer convex part on the first side edge of the adjacent second blade; first outer convex part on the second side of first blade, first interior concave part just set up with second interior concave part, the outer convex part of second on the second side of adjacent second blade respectively. The flow channel formed between two adjacent blades can be subdivided into stable sub-flow channels along the axial direction of the impeller by the structural design, so that the problem of mutual interference of air flow in the axial direction of the impeller is reduced, and aerodynamic noise is reduced.

As another preferred embodiment, the wavy edge of the first blade includes first outer convex portions and first inner concave portions which are alternately arranged and connected, the wavy edge of the second blade includes second outer convex portions and second inner concave portions which are alternately arranged and connected, the wavy edge is formed only on the first side edge of each of the first blade and the second blade, and the first outer convex portions and the first inner concave portions on the first side edge of the first blade are respectively arranged opposite to the second inner concave portions and the second outer convex portions on the first side edge of the adjacent second blade; above-mentioned structural design can make the reverse swirl that the wave edge of the air current flow through two adjacent blade trailing edges formed can effectively offset, has guaranteed that the air current of the circumference air outlet side of impeller flows out more evenly.

Or, the wave edge of first blade is including setting up and continuous first outer convex part and first interior concave part in turn, the wave edge of second blade is including setting up and continuous second outer convex part and the interior concave part of second in turn, first blade and second blade all only have the shaping on the second side the wave edge, the outer convex part of second on the second side of first blade, the interior concave part of second respectively with the second on the second side of adjacent second blade interior concave part, the outer convex part of second just to setting up. Above-mentioned structural design can make the reverse swirl that the wave edge of airflow flow through adjacent two blade leading edges formed can effectively offset equally, has guaranteed that the airflow outflow of the circumference air outlet side of impeller is more even. On the other hand, the flow channel formed between two adjacent blades of the impeller is naturally divided into a plurality of relatively independent sub-flow channels along the axial direction of the impeller, so that the airflows in the adjacent sub-flow channels cannot be influenced mutually, and the flowing stability of the airflow in the whole flow channel is ensured.

As another preferred embodiment, the wavy edge of the first blade includes first outer convex portions and first inner concave portions which are alternately arranged and connected, and the wavy edge of the second blade includes second outer convex portions and second inner concave portions which are alternately arranged and connected, the wavy edge is formed on only the first side edge of the first blade, and the wavy edges are formed on only the second side edges of the second blade. The structure is arranged, the flow channel formed between two adjacent blades of the impeller is naturally divided into a plurality of relatively independent sub-channels along the axial direction of the impeller, and the wavy edge of the air inlet side and the edge of the air outlet side of the flow channel formed between the two adjacent blades of the impeller are respectively positioned on two different blades aiming at each sub-channel, so that the lengths of flow paths of airflow in the sub-channels are basically consistent, and the uniformity and the stability of airflow in the whole impeller flow channel are ensured.

In order to further reduce aerodynamic noise in the running process of the impeller, the cross section of each blade is in a circular arc shape, the radius of each blade is R0, the width of each blade is D0, and 0.4D0 is larger than or equal to R0 and smaller than or equal to 1.2D 0.

As an improvement, the amplitude of the wavy edge of the blade is H, the width of the blade is D when the blade is unfolded into a flat plate shape, and H is more than or equal to 0.05D and less than or equal to 0.3D.

Further improved, the length of the blade is L0, the length of the blade corresponding to one cycle period of the upper wavy edge of the blade is L, wherein L is more than or equal to 0.04L0 and less than or equal to 0.2L 0.

The wavy edge of the blade can adopt various existing wavy structures with periodic convex-concave change, and preferably, the wavy edge of the blade is a sine wave or a sawtooth wave which periodically changes along the axis of the impeller.

The technical scheme adopted by the utility model for solving the third technical problem is as follows: a centrifugal fan using the impeller for the centrifugal fan.

Compared with the prior art, the utility model has the advantages that: the wave-shaped convex and concave parts of two adjacent blades on the impeller are completely complementary in shape, so that reverse vortex generated when airflow flows through the wave-shaped edges of the air inlet side or the air outlet side of the two adjacent blades can be effectively resisted and eliminated as much as possible, the flowing uniformity of the air inlet airflow and the air outlet airflow of the impeller is improved, the sound quality of the centrifugal fan is improved, and the noise is reduced. On the other hand, the two blades with the complementary wavy edges can be obtained by cutting the same substrate at one time, so that the processing steps of the blades are simplified, and the problem of material waste is avoided. In a preferable scheme, the blade is designed into an equal-width structure with waved edges on both sides, so that the same width of the blade along the axial direction can be kept, and the higher static pressure can be kept while the flow separation noise is reduced.

Drawings

Fig. 1 is a schematic perspective view of an impeller in embodiment 1 of the present invention;

FIG. 2 is a front view of FIG. 1;

FIG. 3 is a front view of a substrate in embodiment 1 of the present invention;

FIG. 4 is a schematic perspective view of embodiment 1 of the present invention;

FIG. 5 is a schematic perspective view of a blade according to embodiment 1 of the present invention;

fig. 6 is a schematic perspective view of an impeller in embodiment 2 of the present invention;

FIG. 7 is a front view of FIG. 1;

FIG. 8 is a front view of a substrate in embodiment 2 of the present invention;

FIG. 9 is a schematic perspective view showing the basic structure in example 2 of the present invention;

FIG. 10 is a schematic perspective view of a blade according to embodiment 2 of the present invention;

FIG. 11 is a front view of a blade in embodiment 2 of the utility model;

fig. 12 is a transverse sectional view of a blade in embodiment 2 of the utility model.

Detailed Description

The utility model is described in further detail below with reference to the accompanying examples.

In the description of the present invention, it is to be understood that the terms "central," "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 invention and to simplify the description, but 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 that the directional terms are used for purposes of illustration and are not to be construed as limiting, for example, because the disclosed embodiments of the present invention may be oriented in different directions, "lower" is not necessarily limited to a direction opposite to or coincident with the direction of gravity. Furthermore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature.

Example 1

Referring to fig. 6-12, an impeller for a centrifugal fan includes a front disk 11, a middle disk 12, a rear disk 13 and blades 20, the front disk 11 and the rear disk 13 are disposed opposite to each other, the middle disk 12 is disposed between the front disk 11 and the rear disk 13, and has sockets for the blades to penetrate through in the circumferential direction, and the sockets are disposed between the front disk 11 and the rear disk 13 and are distributed at intervals in the circumferential direction of the front disk 11. The blade has a first side 23 corresponding to the air flow inlet side and a second side 24 corresponding to the air flow outlet side, and the blade of the present embodiment is preferably a curved blade, that is, the cross section of the blade is circular arc. The conventional centrifugal fan impeller is usually designed to prevent the air flow from being separated from the negative pressure surface side of the blade by designing one of the first side edge 23 and the second side edge 24 of each blade as a wavy edge 201, and reduce aerodynamic noise, as shown in fig. 6 in detail.

Referring to fig. 10 and 11, in the present embodiment, the first side 23 and the second side 24 of the blade 20 each have a wavy edge 201 that varies periodically along the axis of the impeller, that is, a double wavy blade, wherein the wavy edge 201 may be one segment or several segments arranged at intervals along the length direction of the first side 23 or the second side 24 of the blade. More specifically, the wavy edge 201 of the blade may adopt various existing wavy structures with periodic convex-concave variation, and the wavy edge 201 of the blade of the present embodiment may be a sine wave or a sawtooth wave periodically varying along the axis of the impeller, and particularly, a sine wave structure is preferable.

Referring to fig. 8 and 9, an important point of the present embodiment is that the two blades 20 used in the impeller can be cut from the same base plate 200, that is, the wavy edges 201 of the two blades can be obtained by one cutting, wherein the wavy edges 201 of the two blades are complementary structures (i.e., the two blades can be seamlessly butted). The base plate 200 may be a strip-shaped flat plate, and may be cut into two parts and then bent to form a blade. Specifically, the blades of the impeller in the present embodiment include a first blade 21 and a second blade 22 arranged at an interval in the circumferential direction of the impeller, wherein the wavy edge 201 of the first blade 21 includes first outer convex portions 231 and first inner concave portions 232 that are alternately arranged and connected, and the wavy edge 201 of the second blade 22 includes second outer convex portions 241 and second inner concave portions 242 that are alternately arranged and connected. The number of the first outer convex portions 231 of the first blade 21 is the same as that of the second inner concave portions 242 of the second blade 22, and the first outer convex portions and the second outer concave portions of the first blade 21 are complementary to each other, and the first inner concave portions and the second outer concave portions of the second blade 22 are complementary to each other.

Referring to fig. 8, another important point of the present embodiment is that the dual-wave-shaped blade in the present embodiment is designed with a constant width, specifically, the first outer convex portion 231 and the first inner concave portion 232 on the first side 23 of the first blade 21 are respectively opposite to the first inner concave portion 232 and the first outer convex portion 231 on the second side 24 of the blade in the transverse direction of the blade, so that the width of the first blade 21 at the wave-shaped edge 201 can be the same. Likewise, the second outer convex portion 241 and the second inner concave portion 242 on the first side 23 of the second blade 22 are respectively arranged opposite to the second inner concave portion 242 and the second outer convex portion 241 on the second side 24 of the blade in the transverse direction of the blade, so that the width of the second blade 22 at the wavy edge 201 is the same. By adopting the design of the blades, the blades can keep the same width along the length direction of the impeller, so that the impeller can keep higher static pressure while reducing the noise of the flow separation, and the starting performance of the centrifugal fan is improved.

Referring to fig. 7, in the present embodiment, a first blade 21 and a second blade 22 cut from the same base plate 200 are adjacently arranged in the circumferential direction of the impeller, wherein a first outer convex portion 231 and a first inner concave portion 232 on a first side 23 of the first blade 21 are respectively disposed opposite to a second inner concave portion 242 and a second outer convex portion 241 on the first side 23 of the adjacent second blade 22. Similarly, the first convex- concave portions 231 and 232 on the second side 24 of the first blade 21 are respectively disposed opposite to the second concave- concave portions 242 and 241 on the second side 24 of the adjacent second blade 22. The flow channel formed between two adjacent blades can be subdivided into stable sub-flow channels along the axial direction of the impeller by the structural design, and aerodynamic noise is reduced.

Referring to fig. 11 and 12, in order to further reduce aerodynamic noise during the operation of the impeller, the cross section of the blade is circular arc, the radius is R0, the width is D0, wherein 0.4D0 ≦ R0 ≦ 1.2D0, and preferably R0 ≦ 0.64D 0. The length of the blade is L0, the length of the blade corresponding to one cycle of the wavy edge 201 on the blade is L, wherein L is more than or equal to 0.04L0 and less than or equal to 0.2L0, and preferably L is less than or equal to 0.07L 0. The amplitude of the wavy edge 201 on the first side 23 and the second side 24 of the blade is H, and the width of the blade in the unfolded flat state is D, wherein H is 0.05D or less and 0.3D or less, and preferably H is 0.2D.

In the embodiment, the blade for the centrifugal fan impeller is formed by cutting the same base plate 200, so that two blades with complementary wavy edges 201 can be obtained by cutting the base plate 200 once, the processing steps of the blades are simplified, and the waste of materials is avoided. In a preferred scheme, the blade is designed into an equal-width structure with the wavy edge 201 on both sides, so that the same width of the blade can be kept along the axial direction, and the high static pressure can be kept while the flow separation noise is reduced.

Example 2

This example differs from example 1 in that: the blades used in the impeller are single undulating blades having the undulating edge 201 described above formed only on the first side 23 or the second side 24. Specifically, the two blades (the first blade 21 and the second blade 22) used in the impeller are also cut from the same base plate 200, that is, the wavy edges 201 of the two blades can be obtained by one-time cutting.

Referring to fig. 1 to 5, the wavy edge 201 may be formed only on the first side 23 of the first blade 21 and the first side 23 of the second blade 22, and specifically, the first outer convex portion 231 and the first inner concave portion 232 on the first side 23 of the first blade 21 are respectively opposite to the second inner concave portion 242 and the second outer convex portion 241 on the first side 23 of the adjacent second blade 22, as shown in fig. 2 in detail. Above-mentioned structural design can make the reverse swirl that the wave edge of the air current flow through two adjacent blade trailing edges formed can effectively offset, has guaranteed that the air current of the circumference air outlet side of impeller flows out more evenly. Similarly, when the wavy edge 201 is formed only on the second side 24 of the first blade 21 and the second side 24 of the second blade 22, specifically, the first outer convex portion 231 and the first inner concave portion 232 on the second side 24 of the first blade 21 may be disposed to face the second inner concave portion 242 and the second outer convex portion 241 on the second side 24 of the adjacent second blade 22, respectively. This kind of structural design can make the reverse swirl that the wave edge of airflow flow through adjacent two blade leading edges formed can effectively offset equally, has guaranteed that the airflow outflow of the circumference air outlet side of impeller is more even. On the other hand, the flow channel formed between two adjacent blades of the impeller can be naturally divided into a plurality of relatively independent sub-flow channels along the axial direction of the impeller, so that the airflows in the adjacent sub-flow channels cannot be influenced with each other, and the flowing stability of the airflow in the whole flow channel is ensured.

Of course, it is conceivable to adopt the impeller structure of a single-wave-shaped blade, and the first blade 21 may be formed with the above-mentioned wave-shaped edge 201 only on the first side edge 23, and the second blade 22 may be formed with the above-mentioned wave-shaped edge 201 only on the second side edge 24. The structure is arranged, the flow channel formed between two adjacent blades of the impeller is naturally divided into a plurality of relatively independent sub-channels along the axial direction of the impeller, and the wavy edge of the air inlet side and the edge of the air outlet side of the flow channel formed between the two adjacent blades of the impeller are respectively positioned on two different blades aiming at each sub-channel, so that the lengths of flow paths of airflow in the sub-channels are basically consistent, and the uniformity and the stability of airflow in the whole impeller flow channel are ensured.

Claims (10)

1. An impeller for a centrifugal fan, comprising:

a front plate (11);

a rear disc (13) arranged opposite to the front disc (11);

the blades (20) are arranged between the front disc (11) and the rear disc (13) and are distributed at intervals along the circumferential direction of the front disc (11), each blade is provided with a first side edge (23) corresponding to one side where airflow flows in and a second side edge (24) corresponding to one side where the airflow flows out, and at least one of the first side edge (23) and the second side edge (24) is provided with a wavy edge (201);

the method is characterized in that: the blades (20) comprise a first blade (21) and a second blade (22) which are arranged at intervals along the circumferential direction of the impeller, and the wavy edge (201) of the first blade (21) and the wavy edge (201) of the second blade (22) are in a complementary structure, namely the wavy edges of the first blade (21) and the second blade (22) can be matched together in a flattened state.

2. The impeller for a centrifugal fan according to claim 1, wherein: the whole side edges of the first blade (21) and the second blade (22) with the wavy edge (201) can be matched together in a flattened state.

3. The impeller for a centrifugal fan according to claim 1 or 2, wherein: the first side edge (23) and the second side edge (24) of each blade of the impeller are provided with the wavy edge (201).

4. The impeller for a centrifugal fan according to claim 3, wherein: the wavy edge (201) of the first blade (21) comprises first outer convex parts (231) and first inner concave parts (232) which are alternately arranged and connected, the wavy edge (201) of the second blade (22) comprises second outer convex parts (241) and second inner concave parts (242) which are alternately arranged and connected, the first outer convex parts (231) and the first inner concave parts (232) on the first side edge (23) of the first blade (21) are respectively opposite to the first inner concave parts (232) and the first outer convex parts (231) on the second side edge (24) of the blade in the transverse direction of the blade, so that the width of the first blade (21) at the wavy edge (201) is the same, and the second outer convex parts (241) and the second inner concave parts (242) on the first side edge (23) of the second blade (22) are respectively opposite to the second inner concave parts (242) on the second side edge (24) of the blade, The second outward protrusions (241) are arranged to face each other in the lateral direction of the blade so that the width of the second blade (22) at the wavy edge (201) is the same.

5. The impeller for a centrifugal fan according to claim 4, wherein: the first outer convex part (231) and the first inner concave part (232) on the first side edge (23) of the first blade (21) are respectively arranged opposite to the second inner concave part (242) and the second outer convex part (241) on the first side edge (23) of the adjacent second blade (22);

first outer convex part (231), first interior concave part (232) on second side (24) of first blade (21) just set up with second interior concave part (242), the outer convex part of second (241) on second side (24) of adjacent second blade (22) respectively.

6. The impeller for a centrifugal fan according to claim 1 or 2, wherein: the wavy edge (201) of the first blade (21) comprises first outer convex parts (231) and first inner concave parts (232) which are alternately arranged and connected, the wavy edge (201) of the second blade (22) comprises second outer convex parts (241) and second inner concave parts (242) which are alternately arranged and connected, the wavy edge (201) is formed on the first side edge (23) of the first blade (21) and the second blade (22), and the first outer convex parts (231) and the first inner concave parts (232) on the first side edge (23) of the first blade (21) are respectively opposite to the second inner concave parts (242) and the second outer convex parts (241) on the first side edge (23) of the adjacent second blade (22);

or, wave edge (201) of first blade (21) is including alternate setting and continuous first outer convex part (231) and first interior concave part (232), wave edge (201) of second blade (22) is including alternate setting and continuous second outer convex part (241) and second interior concave part (242), first blade (21) and second blade (22) all only have on second side (24) shaping wave edge (201), second outer convex part (241), second interior concave part (242) on second side (24) of first blade (21) respectively with second interior concave part (242), the outer convex part (241) of second on second side (24) of adjacent second blade (22) just to setting up.

7. The impeller for a centrifugal fan according to claim 1 or 2, wherein: the wavy edge (201) of the first blade (21) comprises first outer convex parts (231) and first inner concave parts (232) which are alternately arranged and connected, the wavy edge (201) of the second blade (22) comprises second outer convex parts (241) and second inner concave parts (242) which are alternately arranged and connected, the first blade (21) is only formed on the first side edge (23) and provided with the wavy edge (201), and the second blade (22) is only formed on the second side edge (24) and provided with the wavy edge (201).

8. The impeller for a centrifugal fan according to claim 1 or 2, wherein: the cross section of the blade (20) is arc-shaped, the radius is R0, the width is D0, and R0 is more than or equal to 0.4D0 and less than or equal to 1.2D 0;

the amplitude of the wavy edge (201) of the blade is H, the width of the blade is D when the blade is unfolded into a flat state, wherein H is more than or equal to 0.05D and less than or equal to 0.3D;

the length of the blade is L0, the length of the blade corresponding to one cycle period of the upper wavy edge (201) of the blade is L, wherein L is more than or equal to 0.04L0 and less than or equal to 0.2L 0.

9. The impeller for a centrifugal fan according to claim 1 or 2, wherein: the wavy edge (201) of the blade is a sine wave or a sawtooth wave which changes periodically along the axis of the impeller.

10. A centrifugal fan using the impeller for a centrifugal fan according to any one of claims 1 to 9.

Images