阅读说明：本技术 一种降噪风机 (Noise reduction fan ) 是由 邵于佶 陈卫星 于 2021-09-15 设计创作，主要内容包括：本发明公开了一种降噪风机,涉及一种风机。目前,吸音组件采用等距的降噪孔,故只能对某一频率段的噪声进行吸声降噪。一种降噪风机,包括蜗壳、设置在蜗壳内的叶轮、以及用于驱动叶轮的电机,所述的蜗壳包括前板、后板和设置在前板和后板之间的侧板；所述侧板的内侧轮廓线构成蜗壳型线,所述的侧板开设多个第一通孔,侧板的外周设有与第一通孔相对的吸音层；所述的后板开设进风口；相邻第一通孔的间距尺寸大于或等于两种,形成侧板的多种通孔率。本技术方案的侧板不同的地方采用不同的通孔率,可以对多频率段的噪声进行吸声降噪,在吸音层的共同作用下,实现低频和高频噪声的有效降低,从而达到整体降噪的目的。(The invention discloses a noise reduction fan, and relates to a fan. At present, the sound absorption component adopts equidistant noise reduction holes, so that sound absorption and noise reduction can be only carried out on noise of a certain frequency band. A noise reduction fan comprises a volute, an impeller arranged in the volute and a motor used for driving the impeller, wherein the volute comprises a front plate, a rear plate and a side plate arranged between the front plate and the rear plate; the inner contour lines of the side plates form volute type lines, the side plates are provided with a plurality of first through holes, and the peripheries of the side plates are provided with sound absorbing layers opposite to the first through holes; the rear plate is provided with an air inlet; the space size of the adjacent first through holes is larger than or equal to two, and various through hole rates of the side plate are formed. Different through-hole rates are adopted in different places of the side plate of the technical scheme, noise of a multi-frequency section can be absorbed and reduced, and effective reduction of low-frequency and high-frequency noise is achieved under the combined action of the sound absorption layer, so that the purpose of integral noise reduction is achieved.)

1. A noise reduction fan comprises a volute, an impeller arranged in the volute and a motor used for driving the impeller, wherein the volute comprises a front plate (1), a rear plate (2) and a side plate (3) arranged between the front plate (1) and the rear plate (2); the inner side contour lines of the side plates (3) form volute type lines, a plurality of first through holes (301) are formed in the side plates (3), and sound absorbing layers (4) opposite to the first through holes (301) are arranged on the peripheries of the side plates (3); the rear plate (2) is provided with an air inlet (5); the method is characterized in that: the space size of the adjacent first through holes (301) is more than or equal to two, and various through hole rates of the side plate (3) are formed.

2. The noise reduction fan according to claim 1, wherein: the volute molded line of the side plate (3) close to the volute tongue (6) is a radial high-pressure end (7); the volute molded line of the side plate (3) close to the air outlet (12) is a radial low-pressure end (8); the distance between the first through holes (301) of the side plate (3) is gradually increased from the volute molded line along the radial high-pressure end (7) to the radial low-pressure end (8), so that the corresponding through hole rate of the side plate (3) is gradually reduced from the volute molded line along the radial high-pressure end (7) to the radial low-pressure end (8).

3. The noise reduction fan according to claim 2, wherein: an axial high-pressure end (9) is arranged at the position, close to the front plate (1), of the side plate (3), and an axial low-pressure end (10) is arranged at the position, close to the rear plate (2), of the side plate (3); the distance between the first through holes (301) of the side plate (3) is gradually reduced from the axial low-pressure end (10) to the axial high-pressure end (9) along the axial direction of the volute, so that the corresponding through hole rate of the side plate (3) is gradually increased from the axial low-pressure end (10) to the axial high-pressure end (9) along the axial direction of the volute.

4. The noise reduction fan according to claim 2, wherein: the circumferential distance between the adjacent first through holes (301) of the radial low-pressure end (8) is A; wherein A is more than or equal to 10mm and less than or equal to 14 mm; the circumferential distance between the adjacent first through holes (301) of the radial high-voltage end (7) is B; wherein B is more than or equal to 6mm and less than or equal to 10 mm.

5. The noise reduction fan according to claim 3, wherein: the axial distance between the adjacent first through holes (301) of the radial low-pressure end (8) is A; wherein A is more than or equal to 10mm and less than or equal to 14 mm; the axial distance between the adjacent first through holes (301) of the radial high-pressure end (7) is B; wherein B is more than or equal to 6mm and less than or equal to 10 mm.

6. The noise reduction fan according to claim 1, wherein: the aperture of the first through hole (301) is D, wherein D is more than or equal to 1.8mm and less than or equal to 2.8 mm.

7. The noise reduction fan according to claim 2, wherein: the through hole rate of the side plate (3) is p 1; wherein p1 is more than or equal to 1.8 percent and less than or equal to 9.6 percent.

8. The noise reduction fan according to claim 1, wherein: the sound absorption layer (4) is pressed against the outer side surface of the side plate (3) through the fixing plate (11); a second through hole (1101) is formed in the fixing plate (11); the through hole rate of the fixing plate (11) is larger than that of the side plate (3).

9. The noise reduction fan according to claim 8, wherein: the through hole rate of the fixing plate (11) is p 2; wherein p2 is more than or equal to 10 percent and less than or equal to 25 percent.

10. The noise reduction fan of claim 9, wherein: the diameter of the second through hole (1101) is E, wherein E is more than or equal to 3mm and less than or equal to 5 mm; the distance between the adjacent second through holes (1101) is C, wherein C is more than or equal to 6mm and less than or equal to 8 mm.

11. The noise reduction fan of claim 10, wherein: the second through hole (1101) is a square hole with the width matched with that of the fixing plate (11); the width of the square hole frame is W, wherein W is more than or equal to 10mm and less than or equal to 30 mm.

12. The noise reduction fan according to claim 1, wherein: the side plate (3) is divided into a plurality of areas along the circumferential direction, each area is divided into a plurality of units, the intervals of the first through holes (301) in the same unit are the same, and the intervals of the first through holes (301) in adjacent units are different, so that units with different through hole rates are formed; the pitches of the first through holes (301) of the corresponding units of different areas are the same.

13. The noise reduction fan of claim 12, wherein: the circumferential spacing and/or the radial spacing of the first through holes (301) of adjacent units in the same area are different.

14. The noise reduction fan according to claim 1, wherein: the volute is vertically arranged, and an oil leakage hole (13) is formed in the middle of the lowest position of the side plate (3); the aperture of the oil leakage hole (13) is at least 3 times of that of the first through hole (301).

Technical Field

The invention relates to a fan, in particular to a noise reduction fan.

Background

The fan is one of the main parts of the integrated cooker, has the function of sucking and exhausting kitchen oil smoke, drives the impeller to rotate through the power of the fan, so that the oil smoke passing through the smoke inlet is sucked into the inner wheel, and then is exhausted to the outside through the air outlet and the smoke pipe of the fan, thereby providing cleaner indoor air of the kitchen for users. At present, integrated kitchen adopts the fan of the big amount of wind to carry out the suction row to the kitchen oil smoke in order to promote the smoking effect usually, but along with the increase of the amount of wind, the noise of fan also increases thereupon, brings relatively poor experience sense for the consumer to bring certain health risk. In order to solve the problem, as shown in fig. 1, some integrated cookers are provided with a sound absorption assembly coated on the side wall of the volute of the fan, and noise reduction is realized by fixing the sound absorption assembly by using a sheet metal part, the sound absorption assembly is provided with equidistant noise reduction holes, and due to the equidistant noise reduction holes, only noise of a certain frequency band can be absorbed and reduced in noise reduction, while the noise frequency band in the fan is wider, so that the overall sound absorption effect is limited by arranging the equidistant holes, and noise reduction is not ideal.

Disclosure of Invention

The technical problem to be solved and the technical task to be solved by the invention are to perfect and improve the prior technical scheme and provide a noise reduction fan so as to achieve the purpose of reducing the noise of the fan. Therefore, the invention adopts the following technical scheme.

A noise reduction fan comprises a volute, an impeller arranged in the volute and a motor used for driving the impeller, wherein the volute comprises a front plate, a rear plate and a side plate arranged between the front plate and the rear plate; the inner contour lines of the side plates form volute type lines, the side plates are provided with a plurality of first through holes, and the peripheries of the side plates are provided with sound absorbing layers opposite to the first through holes; the rear plate is provided with an air inlet; the method is characterized in that: the space size of the adjacent first through holes is larger than or equal to two, and various through hole rates of the side plate are formed. Different through-hole rates are adopted in different places of the side plate of the technical scheme, noise of a multi-frequency section can be absorbed and reduced, and effective reduction of low-frequency and high-frequency noise is achieved under the combined action of the sound absorption layer, so that the purpose of integral noise reduction is achieved.

As a preferable technical means: the volute molded line of the side plate close to the volute tongue is a radial high-pressure end; the volute molded line of the side plate close to the air outlet is a radial low-pressure end; the distance between the first through holes of the side plate is gradually increased from the volute molded line along the radial high-pressure end to the radial low-pressure end, so that the through hole rate corresponding to the side plate is gradually reduced from the volute molded line along the radial high-pressure end to the radial low-pressure end. The side plate adopts high through hole rate at the radial high-pressure end and relatively low through hole rate at the radial low-pressure end, and the corresponding through hole rates are set according to the noise of different frequency bands, so that the noise can be better absorbed and reduced, the low-frequency and high-frequency noise can be effectively reduced, and the aim of integral noise reduction is further fulfilled.

As a preferable technical means: the position of the side plate close to the front plate is an axial high-pressure end, and the position of the side plate close to the rear plate is an axial low-pressure end; the first through hole space of the side plate is gradually reduced from the axial low-pressure end to the axial high-pressure end along the axial direction of the volute, so that the corresponding through hole rate of the side plate is gradually increased from the axial low-pressure end to the axial high-pressure end along the axial direction of the volute. According to the technical scheme, different through hole rates are also arranged in the axial direction, a low-pass hole rate is adopted at the low-pressure end in the axial direction, a low-pass hole rate is adopted at the high-pressure end in the axial direction, and the noise reduction effect is submitted according to the different pressures and the corresponding through hole rates set according to the noise frequency bands generated by the pressures in the axial direction; or a high through-hole rate can be adopted at the radial high-pressure end, and a relatively low through-hole rate can be adopted at the radial low-pressure end; the frequency range of reducing the noise is wider, so that the noise is further reduced, and the noise of the whole machine is lower.

As a preferable technical means: the circumferential distance between the adjacent first through holes of the radial low-pressure end is A; wherein A is more than or equal to 10mm and less than or equal to 14 mm; the circumferential distance between the adjacent first through holes of the radial high-voltage end is B; wherein B is more than or equal to 6mm and less than or equal to 10 mm. The penetration rate of noise is ensured, the frequency range of noise reduction can be considered, and the sound absorption layer is promoted to well absorb sound waves.

As a preferable technical means: the axial distance between the adjacent first through holes of the radial low-pressure end is A; wherein A is more than or equal to 10mm and less than or equal to 14 mm; the axial distance between the adjacent first through holes of the radial high-pressure end is B; wherein B is more than or equal to 6mm and less than or equal to 10 mm. The penetration rate of noise is further ensured, the frequency band range of noise reduction can be effectively covered, and sound absorption layer is promoted to well absorb sound waves, so that the overall noise reduction effect is improved.

As a preferable technical means: the aperture of the first through hole is D, wherein D is more than or equal to 1.8mm and less than or equal to 2.8 mm. Ensuring the penetration rate of noise.

As a preferable technical means: the through hole rate of the side plate is p 1; wherein p1 is more than or equal to 1.8 percent and less than or equal to 9.6 percent. The through hole rate has a proper span range, and the penetration rate and the multi-band noise reduction effect can be considered, so that the overall noise reduction effect is improved.

As a preferable technical means: the sound absorption layer is pressed against the outer side surface of the side plate through the fixing plate; the fixing plate is provided with a second through hole; the through hole rate of the fixing plate is larger than that of the side plate. The penetration rate of noise to the sound absorption layer is guaranteed, sound absorption of the sound absorption layer to sound waves is promoted, and the overall noise reduction effect is good. The fixing plate can be welded with the side plate to realize the connection of the fixing plate and the side plate; of course, the fixed plate and the side plate can be detachably connected by adopting a connection mode through the connecting piece, and the connection mode can conveniently realize the replacement of the sound absorption layer and is favorable for the cleaning of the fan.

As a preferable technical means: the through hole rate of the fixing plate is p 2; wherein p2 is more than or equal to 10 percent and less than or equal to 25 percent. The strength of the fixing plate can be considered, and the connection reliability and the penetration rate of noise to the sound absorption layer are guaranteed.

As a preferable technical means: the diameter of the second through hole is E, wherein E is more than or equal to 3mm and less than or equal to 5 mm; the distance between the adjacent second through holes is C, wherein C is more than or equal to 6mm and less than or equal to 8 mm. The second through holes have proper diameter range and spacing, so that the strength of the fixing plate is ensured, and the connection reliability of the fixing plate is improved; but also can improve the penetration rate of noise to the sound absorption layer and improve the whole noise reduction effect.

As a preferable technical means: the second through hole is a square hole with the width matched with that of the fixing plate; the width of the square hole frame is W, wherein W is more than or equal to 10mm and less than or equal to 30 mm. The second through hole is matched with the width of the fixing plate, so that the shielding of the sound absorption layer is reduced, and the penetration rate of noise to the sound absorption layer is improved; the frame of the fixing plate can support the sound absorption layer on the side plate, so that the sound absorption layer can be coated on the side plate, and the noise reduction effect and the connection reliability are ensured.

As a preferable technical means: the side plate is divided into a plurality of areas along the circumferential direction, each area is divided into a plurality of units, the intervals of the first through holes in the same unit are the same, and the intervals of the first through holes of adjacent units are different, so that units with different through hole ratios are formed; the pitches of the first through holes of the corresponding units in different areas are the same. Because curb plate circumferential direction's size is greater than curb plate radial dimension far away, through being divided into a plurality of regions at circumferential direction, a region is corresponding to stamping die's a punching press, and a plurality of regions correspond stamping die's a lot of punching presses, can realize that a stamping die processes the punching work of accomplishing the first through-hole of curb plate through removing, is favorable to reduce cost, reduces stamping die's volume.

As a preferable technical means: the circumferential spacing and/or the radial spacing of the first through holes of the adjacent units in the same area are different.

As a preferable technical means: the circumferential intervals of the first through holes of the adjacent units in the same area are different.

As a preferable technical means: the volute is vertically arranged, and an oil leakage hole is formed in the middle of the lowest position of the side plate; the aperture of the oil leakage hole is at least 3 times of that of the first through hole.

Has the advantages that: different through-hole rates are adopted in different places of the side plate of the technical scheme, noise of a multi-frequency section can be absorbed and reduced, and effective reduction of low-frequency and high-frequency noise is achieved under the combined action of the sound absorption layer, so that the purpose of integral noise reduction is achieved.

Drawings

Fig. 1 is a schematic diagram of a conventional structure.

Fig. 2 is a schematic view of a volute structure according to a first embodiment of the present invention.

Fig. 3 is a schematic diagram of the explosion structure of the volute according to the first embodiment of the invention.

FIG. 4 is a schematic view of the fan internal radial pressure of the present invention.

FIG. 5 is a schematic view of the fan internal axial pressure of the present invention.

Fig. 6 is a schematic view of a side panel unfolding structure according to a first embodiment of the present invention.

Fig. 7 is a schematic view of an unfolded fixing plate according to a first embodiment of the present invention.

Fig. 8 is a schematic diagram of the explosion structure of the volute according to the second embodiment of the present invention.

Fig. 9 is a schematic view of the side panel unfolding structure of the third embodiment of the present invention.

Fig. 10 is a schematic perspective view of a bent side plate according to a third embodiment of the present invention.

In the figure: 1. a front plate; 2. a back plate; 3. a side plate; 301. a first through hole; 4. a sound absorbing layer; 5. an air inlet; 6. a volute tongue; 7. a radial high pressure end; 8. a radial low pressure end; 9. an axial high pressure end; 10. an axial low pressure end; 11. a fixing plate; 1101. a second through hole; 12. an air outlet; 13. an oil leakage hole.

Detailed Description

The technical scheme of the invention is further explained in detail by combining the drawings in the specification.

In the description of the present invention, it is to be understood that the terms "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "inner," "outer," "axial," "radial," "circumferential," and the like are used in the orientation or positional relationship indicated in the drawings for convenience in describing the present invention and for simplicity in description, and do not indicate or imply that the devices or elements being referred to must have a particular orientation, be constructed and operated in a particular orientation, and that the directional terms are for illustrative purposes only and are not to be construed as limiting, e.g., "upper" and "lower" are not necessarily limited to directions opposite or consistent with the direction of gravity.

The first embodiment is as follows:

as shown in fig. 4, in the radial direction of the circumference inside the fan, the flow field pressure at the rear end of the volute tongue 6 is high, the noise frequency band is also high, and to the air outlet 12, the flow field pressure is low, and the noise frequency band is also low.

As shown in fig. 5, in the axial direction inside the fan, the flow field pressure at the air inlet 5 is lower, and the noise frequency band is also lower, and the closer to the fan back plate 2, the higher the flow field pressure is, and the higher the noise frequency band is, and as shown in fig. 4 and 5, the flow field inside the fan is more complex, and the noise frequency band range is also wider.

In order to reduce noise, the invention adopts the following structure:

as shown in fig. 2, 3, 6, and 7, the present invention includes a scroll casing including a front plate 1, a rear plate 2, and a side plate 3 disposed between the front plate 1 and the rear plate 2; the inner contour lines of the side plates 3 form volute type lines, the side plates 3 are provided with a plurality of first through holes 301, and the peripheries of the side plates 3 are provided with sound absorption layers 4 opposite to the first through holes 301; the rear plate 2 is provided with an air inlet 5; the volute molded line of the side plate 3 close to the volute tongue 6 is a radial high-pressure end 7; the volute molded line of the side plate 3 close to the air outlet 12 is a radial low-pressure end 8; the through-porosity of the side plate 3 decreases from the volute line along which the radial high-pressure end 7 follows to the radial low-pressure end 8. Different through-hole rates are adopted in different places of the side plate 3 of the technical scheme, high through-hole rate is adopted at the radial high-pressure end 7, relatively low through-hole rate is adopted at the radial low-pressure end 8, sound absorption and noise reduction can be carried out on the noise of a multi-frequency section, and effective reduction of low-frequency and high-frequency noise is realized under the combined action of the sound absorption layer 4, so that the purpose of integral noise reduction is achieved. The sound absorbing layer 4 may be a porous flexible body such as sound absorbing cotton or sponge.

When the volute is vertically arranged, in order to prevent oil from accumulating on the side plate 3, an oil leakage hole 13 is formed in the middle of the lowest position of the side plate 3, and oil flows out of the oil leakage hole 13; the aperture of the oil leakage hole 13 is far larger than that of the first through hole 301, and the diameter of the oil leakage hole 13 is at least 3 times that of the first through hole 301.

To further expand the noise reduction band: the position of the side plate 3 close to the front plate 1 is an axial high-pressure end 9, and the position of the side plate 3 close to the rear plate 2 is an axial low-pressure end 10; the through-porosity of the side plate 3 increases gradually from the axial low-pressure end 10 to the axial high-pressure end 9 in the axial direction of the volute. In the technical scheme, different through hole rates are also arranged in the axial direction, and the low through hole rate is adopted at the axial low-voltage end 10; low porosity is used at the axial high pressure end 9; a high through-hole rate is adopted at the radial high-pressure end 7, and a relatively low through-hole rate is adopted at the radial low-pressure end 8; the frequency range of reducing the noise is wider, so that the noise is further reduced, and the noise of the whole machine is lower.

In order to ensure the penetration rate of noise and also consider the frequency band range of noise reduction, in this embodiment: the circumferential distance between the adjacent first through holes 301 of the radial low-voltage end 8 is A; wherein A is 12 mm; the circumferential distance between the adjacent first through holes 301 of the radial high-voltage end 7 is B; wherein B is 8 mm.

The axial distance between the adjacent first through holes 301 of the radial low-pressure end 8 is also A; a is 12 mm; the axial distance between the adjacent first through holes 301 of the radial high-pressure end 7 is also B; wherein B is 8 mm.

The above can form the region with the lowest porosity: the axial and circumferential distances between adjacent first through holes 301 are both 12 mm; the region with the highest through-hole rate: the axial and circumferential spacing of the adjacent first through holes 301 is 8 mm; the axial and circumferential spacing of the adjacent first through holes 301 in the other areas is between 8 and 12mm, so that various combinations are formed; the frequency band range of the noise reduction is expanded. Effectively promote whole noise reduction effect.

The aperture of the first through hole 301 is D, wherein D is more than or equal to 1.8mm and less than or equal to 2.8 mm. The first through hole 301 in this aperture can avoid too much fluid to permeate into the noise damping layer, guarantees the life on noise damping layer, prescribes a limit to the size of the aperture D of first through hole 301, avoids the aperture too big, leads to pressure differential change too much, and then the energy disappears too much, influences the efficiency. The size of the aperture can be different according to the power of the fan, and the corresponding aperture can be selected, so that the penetration rate of noise is ensured.

In order to take account of the penetration rate and the noise reduction effect of multiple frequency bands: the through hole rate of the side plate 3 is p 1; wherein p1 is more than or equal to 1.8 percent and less than or equal to 9.6 percent; the through-hole rate has a suitable span range, and noise elimination of multi-band noise is realized, so that the overall noise reduction effect is improved, too much oil can be prevented from permeating into the noise elimination layer, the working reliability of the noise elimination layer is ensured, and the service life of the noise elimination layer is prolonged.

In order to improve the connection reliability of the sound absorption layer 4, the sound absorption layer 4 is pressed on the outer side surface of the side plate 3 through the fixing plate 11; a second through hole 1101 is formed in the fixing plate 11; the through-hole rate of the fixing plate 11 is greater than that of the side plate 3. The penetration rate of noise to the sound absorption layer 4 is ensured, the sound absorption layer 4 is promoted to well absorb sound waves, and the whole noise reduction effect is good. The fixing plate 11 can be welded with the side plate 3 to realize the connection of the fixing plate 11 and the side plate 3; of course, the fixed plate 11 and the side plate 3 can be detachably connected by adopting a connection mode through a connecting piece, and the connection mode can conveniently realize the replacement of the sound absorption layer 4 and is beneficial to the cleaning of the fan. The connecting piece can be a screw, a buckle and the like.

In order to take account of the strength and noise reduction effect of the fixing plate 11: the fixed plate 11 has a through-hole ratio p 2; wherein p2 is more than or equal to 10 percent and less than or equal to 25 percent. The strength of the fixing plate 11 can be considered, and the connection reliability and the penetration rate of noise to the sound absorption layer 4 can be ensured.

To ensure the strength of the fixing plate 11 and the penetration of noise: the diameter of the second through hole 1101 is E, wherein E is more than or equal to 3mm and less than or equal to 5 mm; the distance between the adjacent second through holes 1101 is C, wherein C is more than or equal to 6mm and less than or equal to 8 mm. The second through holes 1101 have a proper diameter range and a proper distance between adjacent holes, so that the strength of the fixing plate 11 is ensured, and the connection reliability is improved; but also can improve the penetration rate of noise to the sound absorption layer 4 and improve the whole noise reduction effect.

Example two

As shown in fig. 8, the same parts as those in the first embodiment are not described again, but the differences are:

the second through hole 1101 is a square hole with a width matched with that of the fixing plate 11; the width of the square hole frame is W, wherein W is more than or equal to 10mm and less than or equal to 30 mm. The second through holes 1101 are matched with the width of the fixing plate 11, so that the shielding of the sound absorption layer 4 is reduced, and the penetration rate of noise to the sound absorption layer 4 is improved; the frame of the fixing plate 11 can press the sound absorption layer 4 on the side plate 3, so that the sound absorption layer 4 can be coated on the side plate 3, and the noise reduction effect and the connection reliability are ensured.

Example three:

as shown in fig. 9 and 10, for the convenience of manufacturing, the side plate 3 is divided into a plurality of zones along the circumferential direction, each zone is divided into a plurality of units, the first through holes 301 in the same unit have the same pitch, and the first through holes 301 in adjacent units have different pitches, so as to form units with different through hole ratios; the pitches of the first through holes 301 of the corresponding units of the different regions are the same. Because curb plate circumferential direction's size is greater than curb plate radial dimension far away, through being divided into a plurality of regions at circumferential direction, a region is corresponding to stamping die's a punching press, and a plurality of regions correspond stamping die's a lot of punching presses, can realize that a stamping die processes the punching work of accomplishing the first through-hole of curb plate through removing, is favorable to reduce cost, reduces stamping die's volume.

The first through holes 301 of adjacent cells in the same region have different circumferential pitches and/or radial pitches. In this embodiment, the circumferential pitches of the first through holes 301 of the adjacent cells in the same region are different, and the radial pitches of the first through holes 301 of the adjacent cells in the same region are the same, so that the processing is more convenient.

The noise reduction fan shown in fig. 2-10 is a specific embodiment of the present invention, which has shown the substantial features and advantages of the present invention, and it is within the scope of the present invention to modify the shape, structure, etc. of the noise reduction fan according to the practical application.