Double-layer porous air guide and noise reduction axial flow fan
By using the silencer and composite buffer block design of the double-layer multi-hole air-guided noise-reducing axial flow fan, the aerodynamic noise and vibration noise problems of the axial flow fan are solved, achieving improved noise reduction effect and vibration resistance, while reducing assembly costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU FULIHUA GENERAL EQUIP
- Filing Date
- 2025-07-23
- Publication Date
- 2026-07-14
Smart Images
Figure CN224496919U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of fans, and in particular to a double-layer multi-hole air-guiding and noise-reducing axial flow fan. Background Technology
[0002] Axial flow fans are prone to aerodynamic and vibration noise during operation. To address aerodynamic noise, current market solutions involve modifying the impeller blades to avoid generating strong air turbulence, thus reducing aerodynamic noise. However, when airflow passes through the blades, periodic vortices still form at the blade trailing edges. These vortices generate high-frequency aerodynamic noise, which is directly transmitted to the air guide tube and collides with it, causing sound wave reflection and superposition, and then radiating outwards. This aerodynamic noise cannot be absorbed or reduced. As for vibration noise, rubber pads are generally used for vibration damping. However, after prolonged use, rubber pads tend to harden due to aging and lose their effectiveness in damping vibrations. Summary of the Invention
[0003] The purpose of this invention is to provide a double-layer, multi-hole, air-guided, noise-reducing axial flow fan that can reduce both aerodynamic and vibration noise.
[0004] To achieve the above objectives, the technical solution adopted by this utility model is: a double-layer multi-hole air-guiding and noise-reducing axial flow fan, comprising: a shroud, an air guide tube, an impeller, a support, and a motor. A central hole is provided at the center of the shroud. The support is circumferentially fixed to the shroud, and the inner ends of the support converge at the central hole. The motor is located in the central hole and connected to the inner ends of each support. The impeller is fixed to the motor, and the leading edge of the blades on the impeller is lower than the trailing edge. A comb tooth is provided on the trailing edge. The outer end of the support extends downward beyond the shroud and is located outside the support. The end is equipped with a connecting plate with through holes. Several notches are evenly distributed around the upper edge of the air duct. U-shaped seats are welded into each notch. A screw is vertically installed in the U-shaped seat. A composite buffer block is fitted on the screw. The connecting plate is fitted onto the screw through the through holes and abuts against the composite buffer block. A locking nut is threaded onto the screw. The locking nut is screwed onto the connecting plate. A silencer is embedded in the air duct. A cavity is left between the silencer and the air duct. Several silencer holes are evenly distributed around the circumference of the silencer.
[0005] Furthermore, in the aforementioned double-layer multi-hole air-guiding noise-reducing axial flow fan, the ratio between the diameter d of the silencing hole and the diameter D of the impeller is: 0.004≤d / D≤0.01, the ratio between the circumferential center distance L of the silencing hole and the diameter D of the impeller is: 0.03≤L / D≤0.08, and the ratio between the axial center distance H of the silencing hole and the diameter D of the impeller is: 0.0065≤H / D≤0.012.
[0006] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, the composite buffer block includes: a buffer rubber block and a buffer spring. A clearance hole for a clearance screw is provided at the center of the buffer rubber block. Four spring countersunk holes are evenly distributed around the perimeter of the buffer rubber block. A buffer spring is inserted into each of the four spring countersunk holes. The bottom of the buffer spring abuts against the bottom wall of the spring support. The top of the buffer spring is 1-1.5mm lower than the top of the spring countersunk hole.
[0007] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, a lower limit groove is provided on the bottom upper wall of the U-shaped seat, an upper limit groove is provided on the bottom lower wall of the connecting plate, the upper side wall of the buffer rubber block is inserted into the upper limit groove, and the lower side wall of the buffer rubber block is inserted into the lower limit groove.
[0008] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, a T-shaped rubber sleeve is installed in the through hole of the connecting plate. The small diameter end of the T-shaped rubber sleeve extends into the through hole, and the large diameter end of the T-shaped rubber sleeve abuts against the connecting plate. The locking nut is screwed on and abuts against the large diameter end of the T-shaped rubber sleeve.
[0009] Furthermore, in the aforementioned double-layer multi-hole air-guiding noise-reducing axial flow fan, the connection structure between the silencer and the air guide is as follows: an outer straight section is provided in the middle of the air guide, and an outwardly flared inlet arc and an outlet arc are integrally extended at the upper and lower ends of the outer straight section, with the upper edge located on the inlet arc; an inner straight section is provided in the middle of the silencer, and an outwardly flared upper and lower locking arc are integrally extended at the upper and lower ends of the inner straight section, respectively; the upper and lower locking arcs are respectively engaged with the inlet arc and the outlet arc through their own elastic deformation; and the silencer holes are provided on the inner straight section and the lower locking arc.
[0010] Furthermore, in the aforementioned double-layer multi-hole air-guiding noise-reducing axial flow fan, the thickness of the silencer is 1 to 1.5 mm, the cavity distance between the silencer and the air guide is 0 to 5.5 mm, and the silencer holes are set on the inner straight section and the lower inverted arc corresponding to the cavity distance of not less than 5 mm.
[0011] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, the trailing edge of the blade is not lower than the top of the inner straight section, and the leading edge of the blade is higher than the bottom of the inner straight section.
[0012] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, the shroud includes: several grid rings with gradually increasing diameters and concentrically arranged, the innermost grid ring serving as the central hole of the shroud, brackets welded to each grid ring, and two connecting rods equally welded on the grid rings between each pair of adjacent brackets.
[0013] Furthermore, in the aforementioned double-layer multi-hole air-guiding and noise-reducing axial flow fan, the spacing between each pair of adjacent grille rings gradually increases from the inside out.
[0014] The advantages of this utility model are as follows: setting a silencer with silencer holes inside the air duct can reduce aerodynamic noise; setting a composite buffer block between the wind cover and the air duct can reduce vibration noise; and connecting the silencer and the air duct through an interlocking structure can eliminate the need for screws, rivets and other accessories, reduce assembly costs, and improve vibration and impact resistance. Attached Figure Description
[0015] Figure 1 This utility model describes a double-layer, multi-hole, air-guided, noise-reducing axial flow fan.
[0016] Figure 2 yes Figure 1 A schematic diagram of the cross-sectional structure.
[0017] Figure 3 yes Figure 2 A schematic diagram of the structure of the composite buffer block. Detailed Implementation
[0018] The technical solution of this utility model will be further described below with reference to the accompanying drawings and preferred embodiments.
[0019] like Figures 1-3As shown, the double-layer multi-hole air-guiding noise-reducing axial flow fan of this utility model includes: a fan cover 1, an air guide tube 2, an impeller 3, a support 4, and a motor 5. The air guide tube 2 has an outer straight section 21 in the middle. An outwardly flared inlet arc 22 and an outlet arc 23 are integrally extended from the upper and lower ends of the outer straight section 21, respectively. An upper edge 24 is provided on the inlet arc 22, and four notches are evenly distributed around the circumference of the upper edge 24. A U-shaped seat 25 is welded into each of the four notches. A screw 251 is vertically installed in the U-shaped seat 25. A silencer 6 is embedded in the air duct 2. The middle part of the silencer 6 is an inner straight section 61. The upper and lower ends of the inner straight section 61 are integrally extended with outward-facing upper retaining arc 62 and lower retaining arc 63, respectively. The upper retaining arc 62 and lower retaining arc 63 are respectively engaged with the inlet arc 22 and the outlet arc 23 by their own elastic deformation, eliminating the need for additional fasteners, reducing assembly costs. The engagement area between arc 62 and inlet inverted arc 22, and the engagement area between lower inverted arc 62 and outlet inverted arc 23, can distribute the load, avoid stress concentration, and enhance the rigid structure between the silencer 6 and the air guide 2. A cavity is left between the silencer 6 and the air guide 2, with a cavity spacing of 0-5.5mm. Several silencing holes 64 are evenly distributed on the inner straight section 61 and the lower inverted arc 63. The silencing holes 64 are set on the inner straight section 61 and the lower inverted arc 63, corresponding to a cavity spacing of not less than 5mm. The thickness of the silencer 6 is 1-1.5mm, which can ensure that the silencer 6 has good elasticity and prevent excessive weight from affecting later installation. When the gas vortex passes through the silencing holes 64 and enters the cavity between the silencer 6 and the air guide 2, it will generate reflection and interference due to impedance change, thereby suppressing the noise of vortex shedding. At the same time, when the gas vortex impacts the silencer 6, 1-1.A 5mm thick silencer 6 provides sound absorption and buffering. A shroud 1 is installed above the air duct 2. The shroud 1 includes several concentrically arranged, gradually increasing diameter grille rings 11. The innermost grille ring 11 serves as the central hole of the shroud 1. Four supports 4 are welded between the grille rings 11, evenly distributed around the shroud 1. The inner ends of the supports 4 converge at the central hole of the shroud 1. Two connecting rods 12 are equally welded to the grille rings 11 between each pair of adjacent supports 4. The spacing between each pair of adjacent grille rings 11 gradually increases from the inside out. This outward-expanding spacing design between the grille rings 11 on the shroud 1 gradually releases airflow pressure, preventing sudden expansion that could cause low-frequency aerodynamic noise. The motor 5 is located... The innermost grid ring 11 is connected to the inner ends of the four supports 4. The impeller 3 is fixed to the motor 5. The leading edge 311 of the blades 31 on the impeller 3 is lower than the trailing edge 312. A comb tooth 313 is provided on the trailing edge 312. The comb tooth 313 on the trailing edge 312 of the blades 31 can decompose the single gas vortex generated when the impeller 3 rotates into multiple smaller vortices, reducing the intensity of vortex shedding and aerodynamic noise. The trailing edge 312 of the blades 31 is not lower than the top of the inner straight section 61, and the leading edge 311 of the blades 31 is higher than the bottom of the inner straight section 61. In this way, the gas vortices generated by the impeller 3 will all pass through the noise reduction holes 64 and will not directly act on the parts without noise reduction holes 64, causing aerodynamic noise to radiate directly and reduce the noise reduction effect.
[0020] The ratio between the diameter d of the silencing hole 64 and the diameter D of the impeller 3 is 0.004 ≤ d / D ≤ 0.01, similar to a frequency screen, precisely covering the noise spectrum peaks generated when the impeller 3 rotates, controlling the resonant frequency and sound absorption bandwidth. If the diameter d of the silencing hole 64 is too small, it will increase airflow resistance and cause regenerated noise; if the diameter d of the silencing hole 64 is too large, it will reduce the noise reduction effect. Controlling d / D between 0.004 and 0.01 can balance the noise reduction effect and airflow resistance. The ratio between the circumferential center distance L of the silencing hole 64 and the diameter D of the impeller 3 is 0.03 ≤ L / D ≤ 0.08, similar to a phase jammer, disintegrating the periodic noise generated when the impeller 3 rotates, and the circumferential density... Excessive density can interfere with boundary layer flow and increase turbulent noise, while insufficient circumferential density can reduce noise reduction coverage and effectiveness. Maintaining an L / D ratio between 0.03 and 0.08 avoids secondary turbulence while ensuring noise reduction. The ratio between the axial center distance H of the silencer hole 64 and the diameter D of the impeller 3 is 0.0065 ≤ H / D ≤ 0.012, similar to an axial filter, matching the boundary layer development order. Excessive axial density weakens the axial acoustic interference effect and reduces noise reduction, while insufficient axial density increases friction loss between the airflow and the impeller, affecting the air volume. Maintaining an H / D ratio between 0.0065 and 0.012 reduces noise without affecting the air volume.
[0021] If the shroud 1 is directly connected to the air guide duct 2, when the motor 5 drives the impeller 3 to rotate, it is easy to cause resonance between the shroud 1 and the air guide duct 2, resulting in vibration and noise. To solve this problem, in this embodiment, the connection structure between the shroud 1 and the air guide duct 2 is as follows: the outer ends of the four supports 4 extend downwards from the shroud 1, and a connecting plate 41 is provided on the outer ends of the supports 4. A through hole is provided on the connecting plate 41, and a T-shaped rubber sleeve 42 is inserted into the through hole. The small diameter end of the T-shaped rubber sleeve 42 extends into the through hole, and the large diameter end of the T-shaped rubber sleeve 42 abuts against the connecting plate 41. An upper limit groove is provided on the lower wall, and a lower limit groove is provided on the bottom upper wall of the U-shaped seat 25. A composite buffer block 7 is fitted on the screw 251 of the U-shaped seat 25 and is inserted into the lower limit groove. A T-shaped rubber sleeve 42 on the connecting plate 41 is fitted on the screw 251 and abuts against the composite buffer block 7. The upper limit groove on the connecting plate 41 is engaged with the composite buffer block 7. A locking nut 252 is threaded on the screw 251 and abuts against the large diameter end of the T-shaped rubber sleeve 42. Vibration is reduced by the composite buffer block 7, thereby reducing the generation of vibration noise.
[0022] The composite buffer block 7 includes a buffer rubber block 71 and a buffer spring 72. A clearance hole 711 for the clearance screw 251 is provided at the center of the buffer rubber block 71. Four spring countersunk holes 712 are evenly distributed around the circumference of the buffer rubber block 71, and a buffer spring 72 is inserted into each of the four spring countersunk holes 712. The buffer spring 72 abuts against the bottom wall of the spring countersunk hole 712, and the top of the buffer spring 72 is 1-1.5mm lower than the top of the spring countersunk hole 712. When the connecting plate 41 on the bracket 4 is connected to the U-shaped seat 25, the locking nut 252 deforms the buffer rubber block 71 and abuts against the buffer spring 72, limiting the movement of the buffer spring 72. The buffer rubber block 71 is compressed by 1-1.5mm. After storing elastic potential energy 1.5mm, the buffer block 71 and the buffer spring 72 work together to offset the natural frequency through the difference in stiffness between the two, preventing the composite buffer block 7 from resonating at a specific vibration frequency and amplifying vibration noise. When there is a small vibration between the wind cover 1 and the air guide 2, the buffer block 71 can absorb the impact force generated by the small vibration through the stored elastic potential energy, thus playing a buffering role. The buffer spring 72 plays a supporting role. When there is a large vibration, the buffer spring 72 can absorb the impact force generated by the large vibration, thus playing a buffering role. Through the buffering effect of the buffer block 71 and the buffer spring 72, the vibration noise between the wind cover 1 and the air guide 2 can be greatly reduced.
[0023] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of this utility model and not to limit it. Although the utility model has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of this utility model. Any modifications or equivalent substitutions that do not depart from the spirit and scope of this utility model should be covered within the protection scope of the claims of this utility model.
Claims
1. A double-layer, multi-hole, air-guiding, noise-reducing axial flow fan, including: A fan shroud, air guide tube, impeller, support, and motor are characterized in that: a central hole is provided at the center of the fan shroud; the support is circumferentially fixed to the fan shroud, and the inner ends of the support converge at the central hole; the motor is located in the central hole and connected to the inner ends of each support; the impeller is fixed to the motor, the leading edge of the blades on the impeller is lower than the trailing edge, and comb teeth are provided on the trailing edge; the outer end of the support extends downward beyond the fan shroud and a connecting plate with through holes is provided on the outer end of the support; several notches are evenly distributed around the upper edge of the air guide tube, and U-shaped seats are welded into each notch; a screw is vertically arranged in the U-shaped seat, and a composite buffer block is fitted on the screw; the connecting plate is fitted onto the screw through the through hole and abuts against the composite buffer block; a locking nut is threaded onto the screw and screwed against the connecting plate; a silencer is embedded in the air guide tube, and a cavity is left between the silencer and the air guide tube; several silencer holes are evenly distributed around the circumference of the silencer.
2. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 1, characterized in that: The ratio between the diameter d of the silencing hole and the diameter D of the impeller is: 0.004≤d / D≤0.01; the ratio between the circumferential center distance L of the silencing hole and the diameter D of the impeller is: 0.03≤L / D≤0.08; and the ratio between the axial center distance H of the silencing hole and the diameter D of the impeller is: 0.0065≤H / D≤0.
012.
3. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 1, characterized in that: The composite buffer block includes a buffer rubber block and a buffer spring. A clearance hole for a clearance screw is provided at the center of the buffer rubber block. Four spring countersunk holes are evenly distributed around the perimeter of the buffer rubber block. A buffer spring is inserted into each of the four spring countersunk holes. The bottom of the buffer spring abuts against the bottom wall of the spring support. The top of the buffer spring is 1-1.5mm lower than the top of the spring countersunk hole.
4. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 3, characterized in that: A lower limit groove is provided on the bottom upper wall of the U-shaped seat, and an upper limit groove is provided on the bottom lower wall of the connecting plate. The upper side wall of the buffer rubber block is inserted into the upper limit groove, and the lower side wall of the buffer rubber block is inserted into the lower limit groove.
5. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 1, characterized in that: A T-shaped rubber sleeve is installed in the through hole of the connecting plate. The small diameter end of the T-shaped rubber sleeve extends into the through hole, and the large diameter end of the T-shaped rubber sleeve abuts against the connecting plate. The locking nut is screwed on and abuts against the large diameter end of the T-shaped rubber sleeve.
6. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 1, characterized in that: The connection structure between the silencer and the air duct is as follows: an outer straight section is provided in the middle of the air duct, and an outwardly flared inlet arc and an outlet arc are integrally extended at the upper and lower ends of the outer straight section, with the upper edge located on the inlet arc. An inner straight section is provided in the middle of the silencer, and an outwardly flared upper and lower locking arc are integrally extended at the upper and lower ends of the inner straight section. The upper and lower locking arcs are respectively locked onto the inlet arc and the outlet arc through their own elastic deformation. The silencer hole is located on the inner straight section and the lower locking arc.
7. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 6, characterized in that: The thickness of the silencer is 1 to 1.5 mm, and the cavity distance between the silencer and the air guide is 0 to 5.5 mm. The silencer holes are set on the inner straight section and the lower inverted arc corresponding to the cavity distance of not less than 5 mm.
8. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 7, characterized in that: The trailing edge of the blade is not lower than the top of the inner straight section, and the leading edge of the blade is higher than the bottom of the inner straight section.
9. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 1, characterized in that: The wind shield includes: several grid rings with gradually increasing diameters and concentric arrangement, with the innermost grid ring serving as the central hole of the wind shield, brackets welded to each grid ring, and two connecting rods equally welded on the grid rings between each pair of adjacent brackets.
10. The double-layer multi-hole air-guiding and noise-reducing axial flow fan according to claim 9, characterized in that: The spacing between each pair of adjacent grid rings gradually increases from the inside out.