Air guide ring and axial flow fan comprising same

1 . An air guide ring for an axial flow fan, comprising:

an annular air guide portion, wherein the annular air guide portion has an axis (x) and is rotationally symmetric about the axis (x), the annular air guide portion comprises an air duct configured to accommodate an impeller of the axial flow fan to rotate therein, the annular air guide portion has an inner side wall and an outer side wall, and the air duct is enclosed by the inner side wall; and

a plurality of noise reduction devices, wherein the plurality of noise reduction devices is arranged on the inner side wall of the annular air guide portion in a circumferential direction of the air guide ring, each noise reduction device of the plurality of noise reduction devices comprises a resonant cavity and a connecting tube, the resonant cavity is provided between the inner side wall and the outer side wall, and the connecting tube is connected to the inner side wall and extends from the inner side wall to the corresponding resonant cavity in a radial direction relative to the axis (x),

wherein each noise reduction device of the plurality of noise reduction devices is configured to reduce noise in the air duct, and each noise reduction device of the plurality of noise reduction devices comprises a channel provided inside the connecting tube, and the channel is in fluid communication with the corresponding resonant cavity and the air duct.

2 . The air guide ring of claim 1 , wherein each noise reduction device of plurality of the noise reduction devices is configured to have a preset inherent frequency to reduce the noise in the air duct by resonating with sound waves having the preset inherent frequency in the noise.

3 . The air guide ring of claim 2 , wherein at least two noise reduction devices of the plurality of noise reduction devices are configured to have different preset inherent frequencies.

4 . The air guide ring of claim 1 , wherein the resonant cavity and the channel of each noise reduction device of the plurality of noise reduction devices extend in the radial direction and extend perpendicular to the inner side wall and the outer side wall.

5 . The air guide ring of claim 1 , wherein the plurality of noise reduction devices is evenly arranged in an array in the circumferential direction.

6 . The air guide ring of claim 5 , wherein:

the plurality of noise reduction devices comprises a plurality of annular dividing walls, and each annular dividing wall of the plurality of annular dividing walls is connected between the inner side wall and the outer side wall, and

the plurality of noise reduction devices further comprises:

first noise reduction devices, wherein the first noise reduction devices comprise first resonant cavities, and the first resonant cavities are enclosed by the plurality of annular dividing walls; and

second noise reduction devices, wherein the second noise reduction devices comprise second resonant cavities, and the second resonant cavities are formed between adjacent annular dividing walls of the plurality of annular dividing walls.

7 . The air guide ring of claim 5 , wherein each noise reduction device of the plurality of noise reduction devices is configured to form the preset inherent frequency via a volume (V) of the resonant cavity, a length (l) of the connecting tube, and an inner tube diameter (d) of the connecting tube.

8 . The air guide ring of claim 5 , wherein the preset inherent frequency of each noise reduction device of the plurality of noise reduction devices is different from those of adjacent noise reduction devices of the plurality of noise reduction devices.

9 . An axial flow fan, comprising:

an impeller; and

the air guide ring according to claim 1 .

10 . The air guide ring of claim 1 , wherein the connecting tube at least partially overlaps a portion of the corresponding resonant cavity in the radial direction.

11 . An air guide ring for an axial flow fan, comprising:

an annular air guide portion, wherein the annular air guide portion has an axis (x) and is rotationally symmetric about the axis (x), the annular air guide portion comprises an air duct configured to accommodate an impeller of the axial flow fan to rotate therein, the annular air guide portion has an inner side wall and an outer side wall, and the air duct is enclosed by the inner side wall; and

a plurality of noise reduction devices, wherein the plurality of noise reduction devices is arranged on the inner side wall of the annular air guide portion in a circumferential direction of the air guide ring, each noise reduction device of the plurality of noise reduction devices comprises a resonant cavity and a connecting tube, the resonant cavity is provided between the inner side wall and the outer side wall, the connecting tube is connected to the inner side wall and extends from the inner side wall to the corresponding resonant cavity in a radial direction relative to the axis (x), and the connecting tube at least partially overlaps a portion of the corresponding resonant cavity in the radial direction,

wherein each noise reduction device of the plurality of noise reduction devices is configured to reduce noise in the air duct.

12 . The air guide ring of claim 11 , wherein each noise reduction device of plurality of the noise reduction devices is configured to have a preset inherent frequency to reduce the noise in the air duct by resonating with sound waves having the preset inherent frequency in the noise.

13 . The air guide ring of claim 12 , wherein at least two noise reduction devices of the plurality of noise reduction devices are configured to have different preset inherent frequencies.

14 . The air guide ring of claim 13 , wherein each noise reduction device of the plurality of noise reduction devices comprises a channel provided inside the connecting tube, and the channel is in fluid communication with the corresponding resonant cavity and the air duct.

15 . The air guide ring of claim 14 , wherein the resonant cavity and the channel of each noise reduction device of the plurality of noise reduction devices extend in the radial direction and extend perpendicular to the inner side wall and the outer side wall.

16 . The air guide ring of claim 14 , wherein the plurality of noise reduction devices is evenly arranged in an array in the circumferential direction.

17 . The air guide ring of claim 16 , wherein:

the plurality of noise reduction devices comprises a plurality of annular dividing walls, and each annular dividing wall of the plurality of annular dividing walls is connected between the inner side wall and the outer side wall, and

the plurality of noise reduction devices further comprises:

first noise reduction devices, wherein the first noise reduction devices comprise first resonant cavities, and the first resonant cavities are enclosed by the plurality of annular dividing walls; and

second noise reduction devices, wherein the second noise reduction devices comprise second resonant cavities, and the second resonant cavities are formed between adjacent annular dividing walls of the plurality of annular dividing walls.

18 . The air guide ring of claim 16 , wherein each noise reduction device of the plurality of noise reduction devices is configured to form the preset inherent frequency via a volume (V) of the resonant cavity, a length (l) of the connecting tube, and an inner tube diameter (d) of the connecting tube.

19 . The air guide ring of claim 16 , wherein the preset inherent frequency of each noise reduction device of the plurality of noise reduction devices is different from those of adjacent noise reduction devices of the plurality of noise reduction devices.