Noise reduction structure, fan and electronic equipment

Abstract

The invention provides a noise reduction structure, a fan and electronic equipment, the noise reduction structure comprises an air guide short pipe (130), the cross section of an inner cavity of the air guide short pipe (130) is polygonal, the air guide short pipe (130) is provided with a front end opening and a rear end opening which are communicated with each other, the rear end opening is used for being communicated with an air inlet or an air outlet of the fan (100), and the front end opening and the rear end opening are communicated with each other. And the air guide short pipe (130) is used for conducting flow guide and noise reduction on inlet air or outlet air of the fan (100). According to the noise reduction structure, inlet air or exhaust air of the fan can be guided, modal cut-off can be conducted on sound waves in the flow guiding process, and the operation noise of the fan can be reliably reduced.

Description

Technical Field

[0001] The present application relates to the technical field of electronic equipment, and in particular to a noise reduction structure, a fan and an electronic equipment. Background Art

[0002] As the performance of electronic devices continues to improve, the power of the electronic devices inside the devices also increases, causing the electronic devices to generate more heat, which requires the cooling fan to have a higher speed to generate a stronger cooling airflow. However, high-speed fans will bring loud aerodynamic noise, affecting consumers' experience.

[0003] In the related art, a common solution is to reduce fan noise by reducing fan speed. At the same time, in order to ensure that the heat dissipation performance of the fan is not affected, this solution also requires increasing the size of the fan to compensate for air volume and pressure. However, increasing the size of the fan means that more space needs to be occupied inside the electronic device, which is disadvantageous to the miniaturization design of the electronic device.

[0004] Another solution is to focus on the shape of the fan blades, and to achieve the effect of suppressing noise generation by optimizing the shape, inclination, number, spacing, etc. of the fan blades. For example, adding a serrated structure to the trailing edge of the blade, or opening holes in the blade. However, researchers in related fields have been looking for noise solutions in the shape of fan blades for many years, and there is not much room for improvement. In addition, improvements in blade shape such as serrations on the trailing edge of the blade and opening holes in the blade will also bring about problems such as increased manufacturing difficulty and increased costs.

[0005] Based on the above situation, providing a fan noise solution that does not affect the heat dissipation performance of the fan and can achieve reliable noise reduction in a limited space has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The embodiment of the present application provides a noise reduction structure, a fan and an electronic device. The noise reduction structure can guide the air intake or exhaust of the fan, and can perform modal cutoff on the sound waves during the guiding process, so as to reliably reduce the operating noise of the fan.

[0007] In a first aspect, a noise reduction structure is provided, comprising: a short air guide tube, the cross-section of the inner cavity of the short air guide tube is a polygon, the short air guide tube has a front port and a rear port that are interconnected, the rear port is used to communicate with the air inlet or outlet of a fan, so that the short air guide tube can guide and reduce the noise of the inlet or outlet of the fan.

[0008] The noise reduction structure provided in the embodiment of the present application includes a short air guide tube, and the short air guide tube includes a front port and a rear port that are interconnected. When the noise reduction structure is configured on a fan, the noise reduction structure can be set on the air inlet or outlet of the fan, and the rear port of the short air guide tube is connected to the air inlet or outlet of the fan, so that the short air guide tube can guide the air inlet or outlet of the fan. In the process of guiding the airflow, the short air guide tube can also play an acoustic mode cutoff role, for example, it can cut off the rotational circumferential sound mode propagating along the axial direction, so that the aerodynamic noise of the fan can be effectively suppressed, and the operating noise of the fan can be effectively reduced.

[0009] In addition, considering that the inner contour of current fans is usually a non-standard circle with straight edges, the cross-section of the inner cavity of the air guide short tube in the embodiment of the present application is also constructed as a polygon, so that the inner contour of the air guide short tube and the shape of the inner contour of the fan can match each other. This not only ensures that the air guide short tube has a larger cross-sectional area to ensure the heat dissipation performance of the fan, but also ensures that the air guide short tube has a better modal cutoff effect on sound waves.

[0010] The noise reduction structure provided in the embodiment of the present application can effectively suppress the axial propagation of the acoustic mode through the acoustic cutoff of the pipeline, realize the attenuation of the sound wave sound pressure, and can effectively reduce the aerodynamic noise of the fan. The noise reduction structure has a small volume and can be installed in the limited space inside the electronic equipment, and has little effect on the heat dissipation performance of the fan itself, or even no effect. The noise reduction structure has a simple structure, does not have problems such as difficult processing and molding or high cost, is conducive to large-scale promotion and implementation, and has great commercial value.

[0011] Here, when the noise reduction structure is installed on the fan, the rear port is the port close to the fan, that is, Figure 6 and Figure 7 The front port is the port closest to the fan bracket, while the front port is the port farthest from the fan. Figure 6 and Figure 7 The port away from the fan bracket. When the rear port of the air guide short tube is connected to the air inlet of the fan, the air can first enter the interior of the air guide short tube through the front port, and then enter the fan through the rear port. When the rear port of the air guide short tube is connected to the air outlet of the fan, the air (exhaust) of the fan enters the interior of the air guide short tube through the rear port, and then is discharged from the front port. In the description of this application, "front" and "rear" do not constitute the only limitation on the installation position of the port. In some cases, the front port here can also be referred to as the first port, and the rear port can be referred to as the second port.

[0012] Optionally, the short air guide pipe may be a hard pipe or a soft pipe, or a straight pipe or a curved pipe, which is not limited in the present application.

[0013] Optionally, the short air guide tube may be a plastic tube or a metal tube, such as a hard plastic tube, but is not limited thereto.

[0014] Optionally, the cross-section of the inner cavity of the air guide short tube may be in the shape of a 3-12-gon, such as a triangular shape, a quadrilateral, a pentagon, a hexagon, a heptagon, an octagon, a nonagon, a decagon, an eleven-gon, or a twelve-sided shape, etc. The polygon may be, for example, a regular polygon.

[0015] Optionally, the cross-section of the inner cavity or inner contour of the air guide short tube is a polygon, some of the edges thereof may be arc-shaped edges, for example, one or more of the edges may be arc-shaped edges, and the remaining edges may be straight edges.

[0016] In a possible implementation manner, in a direction from the front port to the rear port, the caliber of the front port gradually decreases.

[0017] While the air guide short pipe plays a modal cutoff role and reduces the sound pressure amplitude, it also has a negative impact, which is to increase the unevenness of the airflow at the fan inlet end, that is, to increase the irregularity of the airflow. Therefore, this application gradually reduces the diameter of the front port so that the front port can optimize the airflow uniformity, thereby alleviating the interference of the front end to the air intake airflow, avoiding the occurrence of abnormal tones, and obtaining noise reduction benefits.

[0018] Here, the caliber gradually decreases, which can be a smooth transition type of gradually getting smaller, or a step-like gradual decrease, or a combination of the above two methods. The present application does not limit the specific implementation method of "gradually reducing the caliber". For example, the structural member formed from the front port to the rear port can be constructed into (including) any shape or structure, that is, its cross-sectional shape on different cross sections can be the same or different, but the overall trend of gradually reducing the caliber is satisfied.

[0019] Optionally, in the direction from the front port to the rear port, the caliber of the front port gradually decreases until it finally becomes the same as the caliber of the air guide short duct.

[0020] In a possible implementation, the front port includes a front end surface that is stepped and gradually concave.

[0021] Specifically, the air guide short tube has a certain wall thickness, and the front end face of the air guide short tube is not a plane, but is composed of multiple (for example, 2, 3 or 4) annular faces of different heights. The height here refers to the distance relative to the rear end face or the relative side plate 122. Due to the different heights, multiple annular faces that are connected in sequence together form a stepped structure and gradually concave toward the inside of the short tube, that is, the closer the annular face is to the rear end face of the short tube. Correspondingly, the smaller the diameter of the annular face is, that is, the outermost (i.e., the front end) annular face has the largest diameter, and the innermost (i.e., the rear end) annular face has the smallest diameter, and the diameter of the innermost annular face is equal to the inner diameter of the air guide short tube.

[0022] While the short air guide tube plays a modal cutoff role and reduces the sound pressure amplitude, it also has a negative impact, which is that it increases the unevenness of the airflow at the fan inlet end, that is, it increases the irregularity of the airflow. Therefore, 2-3 layers of stepped features can be added to a certain thickness space of the air inlet end face (i.e., the front end face), that is, the front end face is set to be composed of multiple annular surfaces, and the multiple annular surfaces are stepped and gradually concave. The multiple annular surfaces can cut the airflow (such as vortex), so as to alleviate the interference of the front end face on the intake airflow, reduce the velocity gradient, and increase the uniformity of the airflow, thereby avoiding the occurrence of abnormal tones. After actual measurement and verification, the stepped front end face does have the effect of reducing the noise of the fan unit.

[0023] In a possible implementation, the front port includes a bell-mouth structure, and the diameter of the bell-mouth structure gradually decreases in the direction from the front port to the rear port. Through the above arrangement, the uniformity of the airflow at the air inlet end can also be increased and optimized, the occurrence of abnormal tones can be avoided, and noise reduction benefits can be obtained.

[0024] In a possible implementation, the fan is an axial flow fan, and the cross-sectional area of ​​the air guide short pipe is greater than or equal to the cross-sectional area of ​​the air guide channel of the fan.

[0025] Through the above arrangement, it is possible to avoid or reduce the adverse effect on the heat dissipation performance of the fan caused by the arrangement of the short air guide tube.

[0026] In some cases, considering that the cross-sectional areas of the air guide short duct and the air guide channel may change in the direction of air flow, the cross-sectional area of ​​the aforementioned air guide short duct is greater than or equal to the cross-sectional area of ​​the air guide channel, which means that the minimum cross-sectional area of ​​the air guide short duct is greater than or equal to the maximum cross-sectional area of ​​the air guide channel, thereby reliably ensuring that the heat dissipation performance of the fan is not affected.

[0027] In a possible implementation, the polygon is a hexagon, an octagon, or a dodecagon. Experimental results show that when the polygon is a hexagon, an octagon, or a dodecagon, better noise reduction benefits can be obtained, the aerodynamic noise of the fan can be effectively suppressed, and the operating noise of the fan can be effectively reduced.

[0028] In a possible implementation, the polygon is an octagon, the fan is an axial flow fan, and the cross-sectional shape of the air guide channel of the fan includes four straight sides and four arcuate sides, and any two adjacent straight sides are connected by one arcuate side.

[0029] Through the above settings, the cross-sectional shape of the air guide short duct can be adapted to the inner contour of the fan, which not only ensures that the air guide short duct has a larger cross-sectional area (i.e., ensures that the heat dissipation performance of the fan is not affected), but also ensures that the air guide short duct has a better modal cutoff effect on sound waves.

[0030] In a possible implementation, the noise reduction structure further includes: a fan bracket, the fan bracket is provided with an opening, the opening constitutes the air inlet or the air outlet, and the opening is sealed and docked with the rear port.

[0031] Through the above arrangement, the short air guide duct and the fan bracket can be integrated into an integrated structure, and the inherent bracket of the fan can be reused. The short air guide duct can be directly set on the air inlet or outlet on the fan bracket, which is conducive to simplifying the structure and reducing the implementation cost, and is also conducive to reducing the volume of the noise reduction structure and facilitating the miniaturization design of electronic equipment.

[0032] In a possible implementation, the fan bracket includes an annular frame and a side plate, the annular frame is used to be mounted on the outer periphery of the fan body of the fan, the side plate covers a port of the annular frame, and the opening is formed on the side plate.

[0033] In a possible implementation, the short air guide pipe and the fan bracket are formed into an integral structure through an integral molding process.

[0034] For example, the one-piece molding process may be injection molding, 3D printing, or powder metallurgy.

[0035] Optionally, in other implementations, the short air guide duct and the fan bracket may also be two independent components, and the two may be connected into an integrated structure by bonding, snapping, or screwing.

[0036] In a possible implementation manner, a reinforcing rib is provided between the short air guide pipe and the fan bracket.

[0037] By providing reinforcing ribs, the connection strength between the short pipe and the fan bracket can be improved, ensuring that the noise reduction structure as a whole has sufficient mechanical strength.

[0038] Optionally, a plurality of reinforcing ribs may be provided and distributed at intervals or evenly on the periphery of the short air guide pipe.

[0039] In a possible implementation, the short air guide tube has a length of 8 to 50 mm.

[0040] For example, it can be 8-10mm, 11-18mm, 12-20mm, 13-23mm, 15-25mm, 18-35mm, 30-40mm, 32-45mm, etc. The height of the air guide short duct can be reasonably selected according to the internal volume of the electronic equipment.

[0041] In a second aspect, a fan is provided, comprising: a noise reduction structure provided by any possible implementation of the first aspect.

[0042] Optionally, the fan may be an axial flow cooling fan.

[0043] In a third aspect, an electronic device is provided, comprising a heating element and the fan provided in the second aspect, wherein the fan is used to dissipate heat for the heating element.

[0044] Optionally, the electronic device may be, for example, a server, a smart host, a whole-house central control host, a router, customer premise equipment (CPE), a base station, a mobile terminal, a computer (such as a desktop computer), a robot, a machine tool, semiconductor processing equipment, a printer, a vacuum cleaner, a hair dryer or a game console, etc., but is not limited thereto.

[0045] Optionally, the type of the heating element is also not limited, for example, it can be various electronic devices such as a chip, a processor, a controller, a heating wire, an integrated circuit or a transistor, but is not limited thereto. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention is a structural exploded diagram of a heat dissipation fan in the prior art.

[0047] Figure 2 It is a structural block diagram of an electronic device provided in an embodiment of the present application.

[0048] Figure 3 It is a structural schematic diagram of the fan provided in an embodiment of the present application from a front perspective.

[0049] Figure 4 It is a schematic structural diagram of the fan provided in an embodiment of the present application from a rear perspective.

[0050] Figure 5 This is a structural exploded diagram of the fan provided in an embodiment of the present application.

[0051] Figure 6 It is a structural schematic diagram of a fan bracket provided in an embodiment of the present application from one perspective.

[0052] Figure 7 It is a structural schematic diagram of the fan bracket provided in an embodiment of the present application from another perspective.

[0053] Figure 8 The following are the top and side views of the fan bracket.

[0054] Fig. 9 It is a cross-sectional view of the noise reduction structure provided in an embodiment of the present application.

[0055] Fig.10 is a cross-sectional view of another example of the air guide duct.

[0056] Fig.11 It is a schematic diagram of the airflow direction when the openings on the fan bracket are used as air inlets and air outlets respectively.

[0057] Fig.12 yes Figure 6 A partial enlarged view of part A.

[0058] Fig.13 It is a schematic diagram of the front end of the air guide short duct including the bell-mouth structure.

[0059] Fig.14 It is a top view of a specific example of the noise reduction structure provided in an embodiment of the present application.

[0060] Reference numerals:

[0061] 10. Cooling fan; 11. Fan frame; 12. Moving blades; 13. Stationary blades;

[0062] 100, fan; 110, fan body; 111, fan frame; 112, moving blades; 113, stationary blades; 114, mounting seat; 115, wheel hub; 116, air guide channel;

[0063] 120. fan bracket; 121. annular frame; 122. side panel; 123. opening;

[0064] 130. air guide short pipe; 131. front end surface; 132. bell mouth structure;

[0065] 140. Strengthen the ribs. DETAILED DESCRIPTION

[0066] The embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and cannot be understood as limiting the present application.

[0067] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or mutual communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0068] In the description of the present application, it should be understood that the terms "upper", "lower", "side", "front", "rear", etc. indicate orientations or positional relationships based on the installation, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0069] It should also be noted that, in the embodiments of the present application, the same figure mark is used to represent the same component or the same part. For the same parts in the embodiments of the present application, the figure may only mark one of the parts or components as an example. It should be understood that the figure mark also applies to other identical parts or components.

[0070] With the development of society and the advancement of science and technology, the miniaturization of consumer-oriented electronic products has become one of the trends in the industry. At the same time, the requirements for heat dissipation of electronic products have become higher and higher, and the traditional conduction heat dissipation method sometimes cannot meet the requirements. Therefore, small cooling fans, as key components for enhancing heat dissipation, are widely used in various electronic devices such as computers, communication servers, routers, etc. However, the ensuing fan noise problem, mainly pneumatic noise, has caused great trouble to R&D personnel and is also a pain point that affects consumers' experience.

[0071] The noise sources of cooling fans mainly include aerodynamic noise, mechanical noise and electromagnetic noise. Among them, aerodynamic noise is the main noise contributor, accounting for about 75%. After exploring the aerodynamic noise mechanism of cooling fans, it can be learned that aerodynamic noise mainly includes two types of noise: discrete noise and broadband noise. Discrete noise, also known as rotational noise, is caused by the interaction between the asymmetric structure around the blades and the circumferential uneven flow field formed by the rotation of the blades. It is related to the speed of the impeller, especially under high speed and low load conditions, this noise is particularly prominent. Broadband noise is also called eddy noise, which is mainly caused by the turbulent boundary layer and the splitting and separation of vortices and vortices when the airflow passes through the blades, causing pressure pulsation on the blades. Caused by eddy noise.

[0072] Discrete noise and broadband noise are the two main types of noise generated by general cooling fans. Taking a 120mm*120mm fan at 9000 rpm as an example, discrete noise accounts for about 75% and broadband noise accounts for about 25%. As the speed decreases, the amplitude of discrete noise will decrease significantly, while the proportion of broadband noise will increase. For axial flow cooling fans and centrifugal cooling fans commonly used in small electronic devices, discrete noise is the main source of fan noise.

[0073] Discrete noise is mainly caused by the mutual interference between the moving blades and the stationary blades. At present, cooling fans with a moving and stationary blade interference structure are widely used in electronic equipment such as servers and communication routers. Figure 1 The figure is a structural exploded diagram of a heat dissipation fan in the prior art. The heat dissipation fan can be used in electronic equipment to dissipate heat for electronic devices in the electronic equipment. The heat dissipation fan is an axial flow fan and has a moving and stationary blade interference structure. Specifically, Figure 1 As shown, the heat dissipation fan 10 includes a fan frame 11, an impeller and a stationary blade support structure. The fan frame 11 is a hollow cylindrical structure with two ends transparent, and the impeller and the stationary blade support structure are arranged in the hollow cylindrical structure. The impeller includes a hub and a plurality of moving blades 12 fixed and spaced at the outer edge of the hub. The stationary blade support structure includes a plurality of stationary blades 13 and a mounting seat. One end of the plurality of stationary blades 13 is connected to the inner wall of the fan frame 11, and the other end is connected to the mounting seat. The mounting seat is used to install a motor, and the motor is used to drive the impeller to rotate to generate airflow. In the process of impeller rotation, due to the interference effect between the moving blades 12 and the stationary blades 13, the heat dissipation fan 10 will generate a large discrete noise, thereby reducing the user experience of the electronic device.

[0074] In the related art, in order to reduce fan noise, a commonly used solution is to change the fan parameters. Specifically, the main source of fan noise is aerodynamic noise, and the size of aerodynamic noise is proportional to the fan speed. Therefore, significant noise reduction benefits can be obtained by reducing the fan speed. At the same time, in order to ensure that the heat dissipation performance of the fan is not affected, it is also necessary to compensate for the air volume and pressure by increasing the size of the fan. The above scheme obtains noise reduction benefits by lowering the fan speed, and in order to ensure that the heat dissipation performance of the fan is not affected, the fan size needs to be increased. Increasing the size of the fan means that more space needs to be occupied inside the electronic device, which is not conducive to the miniaturization design of the electronic device.

[0075] Another solution is to focus on the shape of the fan blades, and to achieve the effect of suppressing noise generation by optimizing the shape, inclination, number, spacing, etc. of the fan blades. For example, adding a serrated structure to the trailing edge of the blade, or opening holes in the blade. However, researchers in related fields have been looking for noise solutions in the shape of fan blades for many years, and there is not much room for improvement. In addition, improvements in blade shape such as serrations on the trailing edge of the blade and opening holes in the blade will also bring about problems such as increased manufacturing difficulty and increased costs.

[0076] Based on the above situation, for those skilled in the art, providing a fan noise solution that does not affect the heat dissipation performance of the fan and can achieve reliable noise reduction in a limited space has become an urgent problem to be solved.

[0077] The present application embodiment first provides an electronic device, Figure 2 1 is a structural block diagram of an electronic device 1000 provided in an embodiment of the present application. Figure 2 As shown, the electronic device 1000 includes a housing, a fan 100 and a heating element 200, and the fan 100 and the heating element 200 are arranged in the housing. The type of the electronic device 1000 is not limited, for example, it can be a server, an intelligent host, a whole house central control host, a router, a customer premise equipment (CPE), a base station, a mobile terminal, a desktop computer, a robot, a machine tool, a semiconductor processing equipment, a printer, a vacuum cleaner, a hair dryer or a game console, etc., which is not specifically limited in this application. In addition, the type of the heating element 200 is also not limited, for example, it can be various electronic devices such as a chip, a processor, a controller, a heating wire, an integrated circuit or a transistor, which is not specifically limited in this application.

[0078] During the operation of the electronic device 1000, the heating element 200 continuously generates heat. In order to prevent the heating element 200 from overheating, the fan 100 can dissipate heat from the heating element 200. Specifically, the airflow generated by the rotation of the fan 100 undergoes forced convection heat exchange with the heating element 200, and the high-temperature airflow after the heat exchange dissipates the heat generated by the heating element 200 to the external environment, thereby achieving the purpose of heat dissipation and cooling of the heating element 200. The fan 100 can be arranged around the heating element 200 and fixedly connected to the housing. The fan 100 and the housing can be detachably assembled, such as riveted, screwed or clamped, so that it is easy to repair, clean and replace the fan.

[0079] The electronic device 1000 may have one or more heating elements 200, and in order to meet the heat dissipation requirements, one or more fans 100 may also be provided. For example, the electronic device 1000 may have multiple fans 100, and the multiple fans 100 are connected to each other and arranged in parallel to form a fan array, and the fan array continuously discharges the heat generated by the heating element 200 to the external environment, ensuring that the heating element 200 is always kept at a relatively low temperature, and the electronic device 1000 can operate reliably for a long time.

[0080] Optionally, the electronic device 1000 also includes a radiator thermally connected to the heating element 200. The radiator first absorbs the heat generated by the heating element 200 by heat conduction, and then the airflow generated by the fan 100 flows through the radiator and undergoes forced convection heat exchange with the radiator, and the heat is taken away by the airflow, so that the heat generated by the heating element 200 can be continuously dissipated to the external environment through the radiator and the fan airflow. The heat dissipation and cooling effect of the heating element 200 can be enhanced by providing a radiator, and since the radiator can conduct heat to any position according to design requirements, it is also beneficial to optimize the internal layout design of the electronic device 1000. The radiator may, for example, include one or more of a heat sink (fin), a heat sink, and a heat pipe.

[0081] The fan 100 is disposed inside the electronic device 1000 and can dissipate heat and cool the heating element 200. The fan 100 can be, for example, a DC fan, an axial flow fan, a cross flow fan, a mixed flow fan or a centrifugal fan, but is not limited thereto. The fan 100 is introduced below by taking an axial flow fan as an example.

[0082] Figure 3 is a schematic diagram of the structure of the fan 100 provided in an embodiment of the present application from a front perspective, Figure 4 is a schematic diagram of the structure of the fan 100 provided in an embodiment of the present application from a back view. Figure 5 is a structural exploded view of the fan 100 provided in an embodiment of the present application, Figure 5Part (a) is a schematic diagram of the structure of the fan body 110. Figure 5 Part (b) in FIG. 1 is a schematic diagram of the structure of the fan bracket 120. Figure 3-Figure 5 As shown, the fan 100 provided in the embodiment of the present application includes a fan body 110 and a fan bracket 120 .

[0083] The fan body 110 is the main structure of the fan 100, and includes a fan frame 111, an impeller, and a stationary blade support structure. The fan frame 11 is a hollow cylindrical structure, and has an air guide channel 116 with two ends that are transparent (through) inside. The impeller and the stationary blade support structure are arranged in the air guide channel 116. The fan frame 11, the impeller, and the stationary blade support structure can all be constructed as flat structures. For example, the air guide channel 116 has a large cross-sectional area and a small longitudinal depth ( Figure 3 The fan frame 11, the impeller and the stationary blade support structure can all be made of lightweight plastic with sufficient strength, which is conducive to reducing the weight of the electronic device 1000.

[0084] like Figure 3-Figure 5 As shown, the outline of the fan frame 111 in the embodiment of the present application is rectangular (for example, square). In other embodiments, the outline of the fan frame 111 may also be circular, elliptical, rhombus or trapezoidal or other structures. The outline (i.e., cross-sectional area) of the air guide channel 116 is roughly circular. In the embodiment of the present application, the outline of the air guide channel 116 includes at least one straight edge. For example, the air guide channel 116 includes 4 pairs of staggered arc edges and straight edges, and the arc edges and straight edges are staggered and connected to form a closed ring. In other words, the shape of the cross section of the air guide channel 116 includes 4 straight edges and 4 arc edges, and any two adjacent straight edges are connected by one arc edge, and any two adjacent arc edges are connected by one straight edge. The four arc edges can be intercepted from the same circle, and the straight edge is equivalent to cutting off a section of the arc of the circle and connecting two adjacent arc edges. By setting the straight edge, it is beneficial to increase the mechanical strength of the fan frame 111, and it can also facilitate the manufacturing and molding (for example, injection molding) of the fan frame 111.

[0085] The impeller is rotatably disposed in the air guide channel 116, and airflow is generated by the rotation of the impeller, so that the heat-generating element 200 can be cooled and cooled. The impeller includes a hub 115 and a plurality of moving blades 112, and the plurality of moving blades 112 protrude and extend radially outward with the central axis of the hub 115 as the center and are evenly arranged on the outer edge of the hub 115. The stationary blade support structure includes a plurality of stationary blades 113 and a mounting seat 114, and one end of the plurality of stationary blades 113 is connected to the inner wall of the fan frame 111, and the other end is connected to the mounting seat 114. The mounting seat 114 is used to install a driving component such as a motor or an electric motor, and the driving component is connected to the hub 115, and is used to drive the impeller to rotate to generate airflow.

[0086] like Figure 3-Figure 5 As shown, in the embodiment of the present application, the fan 100 is an axial flow fan, and the impeller pushes the air in the same direction as the axis (i.e. Figure 3 The impeller and the stationary blade support structure can be arranged along the axial direction (the direction of air flow). For example, the stationary blade support structure can be arranged on the downstream side of the impeller, and the airflow generated by the impeller flows to the outside of the fan after passing through the stationary blade support structure.

[0087] Figure 6 It is a structural schematic diagram of the fan bracket 120 provided in an embodiment of the present application from one perspective. Figure 7 FIG. 1 is a schematic structural diagram of the fan bracket 120 provided in another perspective of the embodiment of the present application. Figure 3-Figure 7 As shown, the fan 100 provided in the embodiment of the present application also includes a fan bracket 120, which can also be called a fan outer frame (the aforementioned fan frame 111 can be called a fan inner frame). The shapes of the fan bracket 120 and the fan body 110 are adapted to each other for achieving the installation and fixation of the fan body 110.

[0088] like Figure 6As shown, in the embodiment of the present application, the fan bracket 120 can be an enclosing bracket sleeved on the periphery of the fan body 110. The fan bracket 120 is a hat-shaped structure as a whole, including an annular frame 121 and a side plate 122. The annular frame 121 is a ring-shaped structure with two ends open as a whole. The side plate 122 covers one of the ports of the annular frame 121 to form a "hat top", and the other port of the annular frame 121 constitutes the "hat mouth" of the hat-shaped structure. The middle part of the side plate 122 is hollowed out to form an opening 123, and the opening 123 can constitute the air inlet or outlet of the fan 100. During assembly, the other port (i.e., the "hat mouth") of the annular frame 121 can be gradually sleeved on the fan body 110. After the fan body 110 is fitted in place, the side of the side plate 122 and the fan body 110 can fit each other, and the opening 123 is opposite to the inlet of the air guide channel 116. In this way, the airflow can enter the interior of the air guide channel 116 through the opening 123 on the side plate 122 (that is, the opening 123 is used as an air inlet), and under the driving and supercharging effect of the impeller, the strong airflow generated passes through the stationary blade support structure and flows to the outside of the fan. Alternatively, the airflow in the air guide channel 116 can also be discharged to the outside of the fan 100 through the opening 123 (that is, the opening 123 is used as an air outlet).

[0089] Figure 8 1 are a top view and a side view of the fan bracket 120, wherein: Figure 8 Part (a) is a top view of the fan bracket 120. Figure 8 Part (b) in FIG. 1 is a side view of the fan bracket 120. Figure 3-Figure 8 As shown, the fan bracket 120 and the fan body 110 are adapted to each other in shape, and the fan body 110 is in a rectangular shape (e.g., a square shape), and the contour or opening shape of the annular frame 121 is also set to a rectangular shape, and the side plate 122 is also set to a rectangular shape. In other implementations, the fan body 110 may be in other shapes such as a circle, and the contour or opening shape of the annular frame 121 is also adaptively set to a circle, and the side plate 122 is also set to a circle.

[0090] like Figure 8 As shown in part (a) of FIG. 1 , in the embodiment of the present application, the shapes (outer contours) of the fan body 110 and the fan bracket 120 are both square, the width w2 of the fan bracket 120 matches the width of the fan body 110, and the size of the opening 123 matches the size of the air guide channel 116, for example, the width w1 of the opening 123 is greater than the width of the air guide channel 116. The area of ​​the opening 123 should be greater than or equal to the cross-sectional area of ​​the air guide channel 116, the opening 123 should be directly opposite to the air guide channel 116, and the contour of the opening 123 should surround the contour of the air guide channel 116 (i.e. Figure 8This helps reduce fan noise while ensuring sufficient air volume. Figure 8 As shown in part (b), the thickness h2 of the fan bracket 120 should be compatible with the thickness of the fan body 110. For example, when the fan body 110 is accurately embedded in the annular frame 121, the inner end surface of the fan body 110 fits with the inner wall surface of the side panel 122, and the outer end surface of the fan body 110 remains flush with the port of the annular frame 121 away from the side panel 122 (i.e., the "cap mouth").

[0091] The above content roughly introduces the basic structure of the fan 100. On the basis of the above fan 100, the embodiment of the present application also provides a noise reduction structure, which can be applied to the fan 100. The noise reduction structure can be regarded as an accessory (external single-body accessory) or a part of the fan 100. The noise reduction structure includes a short air guide tube 130 with a polygonal cross-section of the inner cavity. In the process of guiding the air intake or exhaust of the fan 100, the short air guide tube 130 can also perform modal cutoff on the sound waves, for example, cut off the rotational circumferential sound mode propagating along the axial direction, which can effectively suppress the aerodynamic noise of the fan 100, thereby reducing the operating noise of the fan 100.

[0092] The noise reduction structure provided in the embodiment of the present application includes a short air guide tube 130 having a polygonal cross-sectional shape. The short air guide tube 130 reduces noise by the modal cutoff effect on sound waves. The specific inventive concept (process) is as follows:

[0093] The essence of noise is the vibration of sound waves. One way to achieve noise reduction is to weaken the vibration of sound waves. According to the basic theory of acoustics, pipes are a good environment for sound wave propagation. For example, the invention of the "stethoscope" utilizes the principle of sound transmission in pipes. At the same time, pipe silencing (silencing) is also an important topic in pipe acoustic research, and there are many related studies. Therefore, using pipes to weaken the vibration of sound waves propagating in them has become a consideration for fan noise reduction.

[0094] For pipes, there are boundaries in the range in which sound waves move, so sound waves can only appear in a specific form in the pipe, that is, "mode". When the convection wave equation is solved under the restriction of a circular or annular pipe, and the general solution is expanded into the Fourier-Bessel form, it will be found that the sound wave solution appears and propagates in the pipe in a spiral form, that is, the sound wave has a rotating circumferential sound mode that propagates axially (in the direction of the pipe length) in the pipe. When analyzing this general solution, the corresponding cutoff frequency fc can be found. When the sound wave frequency f is lower than the cutoff frequency fc, the axial wave number is an imaginary number, and the exponential term of the propagation factor will add an absolute value. At this time, the sound pressure amplitude will decay exponentially with the increase of the axial distance. According to the record of the pipe sound mode attenuation diagram in the literature, even if the pipe length is only 10 to 20 mm, the attenuation of the modal amplitude can reach 40%-50%. At the same time, considering the actual use scenario of the cooling fan, that is, it is generally a narrow space inside the shell, so it is highly likely that the longer pipe length size cannot be met. Therefore, the length of the pipe (i.e. short pipe) can be preliminarily determined as 10mm, and based on this value, it can be adjusted up or down according to the actual available space.

[0095] After determining that the short tube is used for noise reduction and the length of the short tube is determined, the shape of the short tube needs to be determined next. Considering the heat dissipation performance of the fan, the setting of the pipe shape should minimize the impact on the heat dissipation flow of the pipe. The larger the cross-sectional area, the larger the volume of airflow that can pass through at the same speed, which is more conducive to heat convection heat dissipation. Therefore, when designing the shape of the pipe, one point that needs to be considered is to maximize the cross-sectional area of ​​the pipe.

[0096] At the same time, a practical factor must also be considered, that is, the shape limitation of the fan itself. According to the investigation of small cooling fans, it is easy to find that the inner contour of a large number of fans is not a standard circle, but a certain change is made on the basis of the circle to add four straight edges in consideration of the structural strength of the fan frame and the difficulty of processing. For example, in Figure 1 In the heat dissipation fan 10 in the prior art shown, the shape of the fan inner contour (i.e., the cross section of the air guide channel) includes 4 arcuate edges and 4 straight edges, and any two adjacent arcuate edges are connected by a straight edge. Therefore, when designing the shape of the short tube, the actual fan inner contour shape should also be considered, which can not only ensure that the short tube has a larger cross-sectional area, but also ensure that the pipeline has a better modal cutoff effect on sound waves.

[0097] In summary, the larger short tube cross-sectional area and the matching with the inner contour of the fan are the two main factors to be considered in designing the pipe shape. Finally, a short tube structure with an octagonal cross-sectional shape was designed to maximize the above conditions. After experimental verification, the octagonal short tube does have a significant effect in reducing the noise of the fan operation.

[0098] Based on the above technical analysis, the specific details of the noise reduction structure provided in the embodiment of the present application are introduced below in conjunction with the accompanying drawings to continue to specifically analyze and solve the technical problems raised in the present application.

[0099] The noise reduction structure provided in the embodiment of the present application can be installed at the air inlet or the air outlet of the fan 100 to reduce the operating noise of the fan 100 . Fig. 9 is a cross-sectional view of a noise reduction structure provided in an embodiment of the present application, wherein: Fig. 9 Part (a) of Figure 7 Cross-sectional view from CC perspective, Fig. 9 Part (b) of Figure 6 Cross-section from the middle BB perspective.

[0100] like Figure 6-Figure 9 As shown, the noise reduction structure provided in the embodiment of the present application includes a short air guide tube 130, the cross-section of the inner cavity of the short air guide tube 130 is polygonal, the short air guide tube 130 has a front port and a rear port that are interconnected, and the rear port is used to be connected to the air inlet or outlet of the fan 100, for example, connected to the opening 123 on the fan bracket 120, so that the short air guide tube 130 can guide and reduce the noise of the air inlet or outlet of the fan 100, thereby reducing the operating noise of the fan 100.

[0101] Specifically, the air guide short tube 130 is a hollow short tube structure with two ends transparent and capable of guiding airflow. The air guide short tube 130 can be a hard tube or a soft tube, or a straight tube or a curved tube, which is not limited in this application. The air guide short tube 130 has a front port and a rear port that are interconnected, wherein the rear port is used to communicate with the air inlet or outlet of the fan 100. When the noise reduction structure is installed on the fan 100, the rear port is the port close to the fan 100, that is, Figure 6 and Figure 7 The front port is the port close to the fan bracket 120, and the front port is the port far away from the fan 100, that is, Figure 6 and Figure 7 The port far away from the fan bracket 120. When the rear port of the air guide short tube 130 is connected to the air inlet of the fan 100, the air can first enter the interior of the air guide short tube 130 through the front port, and then enter the fan 100 through the rear port. When the rear port of the air guide short tube 130 is connected to the air outlet of the fan 100, the outlet air (exhaust air) of the fan 100 enters the interior of the air guide short tube 130 through the rear port, and then is discharged from the front port. In the description of this application, "front" and "rear" do not constitute a limitation on the installation position of the port. In some cases, the front port here can also be called the first port, and the rear port can be called the second port.

[0102] Optionally, the short air guide tube 130 may be a plastic tube or a metal tube, such as a hard plastic tube, but is not limited thereto.

[0103] like Figure 6 as well as Fig. 9 As shown in part (a) of the figure, the cross section of the inner cavity of the air guide short tube 130 is a polygon (for example, an octagon in the figure), that is, the shape of the radial cross section of the inner wall (inner diameter) of the air guide short tube 130 is a polygon, or in other words, the inner contour of the air guide short tube 130 is a polygon. A plane figure composed of three or more straight edges (line segments) connected end to end is called a polygon. Therefore, the cross section of the inner cavity of the air guide short tube 130 in the present application can be a 3-12-sided polygon, for example, a triangular (triangle), quadrilateral, pentagon, hexagon, heptagon, octagon, nonagon, decagon, eleven-sided polygon or twelve-sided deformation. The polygon can be, for example, a regular polygon.

[0104] Optionally, in the embodiment of the present application, the cross-section of the inner cavity or inner contour of the air guide short tube 130 is a polygon, some of the edges thereof may be arc-shaped edges, for example, one or more of the edges may be arc-shaped edges, and the remaining edges may be straight edges.

[0105] For example, the cross section of the inner cavity of the air guide short tube 130 is an octagon, which is similar to Figure 1 or Figure 3 The profile of the middle air guide channel includes 4 straight edges and 4 curved edges, any two adjacent straight edges are connected by one curved edge, and any two adjacent curved edges are connected by one straight edge.

[0106] like Figure 6 as well as Fig. 9 As shown in part (a), the cross-sectional shape (ie, outer contour) of the outer wall of the air guide short tube 130 can be a polygon, that is, the inner wall and the outer wall of the air guide short tube 130 are parallel to each other, and the tube wall thickness is the same at all locations. Fig.10 is a cross-sectional view of another example of the air guide short duct 130. Fig.10 In other implementations shown, the cross-sectional shape (ie, outer contour) of the outer wall of the air guide short tube 130 may also be a circle or other shapes, and in this case, the tube wall thickness at different locations of the air guide short tube 130 may be different.

[0107] The noise reduction structure provided in the embodiment of the present application includes a short air guide tube 130, which includes a front port and a rear port that are interconnected. When the noise reduction structure is configured on the fan 100, the noise reduction structure can be set on the air inlet or outlet of the fan 100, and the rear port of the short air guide tube 130 is connected to the air inlet or outlet of the fan 100, so that the short air guide tube 130 can guide the air inlet or outlet of the fan 100. In the process of guiding the airflow, the short air guide tube 130 can also play an acoustic mode cutoff role, for example, it cuts off the rotational circumferential acoustic mode propagating along the axial direction, so that the aerodynamic noise of the fan 100 can be effectively suppressed, and the operating noise of the fan 100 can be effectively reduced.

[0108] In addition, considering that the inner contour of current fans is usually a non-standard circle with straight edges, the cross-section of the inner cavity of the air guide short tube 130 in the embodiment of the present application is also constructed as a polygon, so that the inner contour of the air guide short tube 130 and the shape of the inner contour of the fan 100 can match each other. This not only ensures that the air guide short tube 130 has a larger cross-sectional area to ensure the heat dissipation performance of the fan 100, but also ensures that the air guide short tube 130 has a better modal cutoff effect on sound waves.

[0109] The noise reduction structure provided in the embodiment of the present application can effectively suppress the axial propagation of the acoustic mode through the acoustic cutoff of the pipeline, realize the attenuation of the sound wave sound pressure, and can effectively reduce the aerodynamic noise of the fan 100. The noise reduction structure has a small volume and can be installed in the limited space inside the electronic device 1000, and has little or no effect on the heat dissipation performance of the fan 100 itself. The noise reduction structure has a simple structure, does not have problems such as difficult processing and molding or high cost, is conducive to large-scale promotion and implementation, and has great commercial value.

[0110] Optionally, the polygon may be a hexagon, an octagon or a dodecagon. Experimental results show that when the polygon is a hexagon, an octagon or a dodecagon, better noise reduction benefits can be obtained, the aerodynamic noise of the fan 100 can be effectively suppressed, and the operating noise of the fan 100 can be effectively reduced.

[0111] Optionally, in the embodiment of the present application, the cross section of the inner cavity or inner contour of the air guide short tube 130 is a polygon, and the polygon can be adapted to the inner contour of the fan 100, such as Figure 3 and Figure 5 As shown, the inner contour of the fan 100 (i.e., the cross-sectional shape of the air guide channel 116) includes 4 straight sides and 4 arc sides, so the cross-sectional shape of the inner cavity of the air guide short tube 130 can be an octagon. This can not only ensure that the air guide short tube 130 has a larger cross-sectional area (i.e., ensure that the heat dissipation performance of the fan 100 is not affected), but also ensure that the air guide short tube 130 has a better modal cutoff effect on sound waves.

[0112] Alternatively, if Figure 8 As shown in part (b), the height h1 of the short air guide tube 130 can be 8 to 50 mm, for example, 8 to 10 mm, 11 to 18 mm, 12 to 20 mm, 13 to 23 mm, 15 to 25 mm, 18 to 35 mm, 30 to 40 mm, 32 to 45 mm, etc. The height of the short air guide tube 130 can be reasonably selected according to the internal volume of the electronic device 1000.

[0113] Furthermore, the noise reduction structure may further include a mounting bracket, through which the air guide short pipe 130 can be reliably mounted on the air inlet or outlet of the fan.

[0114] Furthermore, the mounting bracket may be the aforementioned fan bracket 120, that is, the mounting bracket may be an inherent bracket of the fan. Figure 6-Figure 9 The noise reduction structure provided by the embodiment of the present application is also shown. Figure 6-Figure 9 As shown, the noise reduction structure provided in the embodiment of the present application may also include the aforementioned fan bracket 120 , the air guide short pipe 130 is arranged on the opening 123 on the fan bracket 120 , and the rear port of the air guide short pipe 130 is sealed and connected to the opening 123 .

[0115] Through the above arrangement, the short air guide duct 130 and the fan bracket 120 can be integrated into an integrated structure, and the inherent bracket of the fan 100 can be reused. The short air guide duct 130 can be directly set on the air inlet or outlet on the fan bracket 120, which is beneficial to simplify the structure and reduce the implementation cost, and is beneficial to reducing the volume of the noise reduction structure, facilitating the miniaturization design of the electronic device 1000.

[0116] Fig.11 1 is a schematic diagram of the airflow direction when the opening 123 on the fan bracket 120 is used as an air inlet and an air outlet. Fig.11 As shown in part (a), the opening 123 can be the air inlet of the fan 100. At this time, the rear port of the air guide short tube 130 is sealed and connected to the air inlet. The air guide short tube 130 guides the air intake of the fan 100. The external air can first enter the tube through the front port of the air guide short tube 130, and then enter the interior of the fan through the rear port of the air guide short tube 130 and the opening 123.

[0117] like Fig.11As shown in part (b), the opening 123 can be the air outlet (i.e., exhaust port) of the fan 100. At this time, the rear port of the air guide short duct 130 is sealed and connected to the air outlet, and the air guide short duct 130 guides the air outlet of the fan 100. The airflow in the fan enters the interior of the air guide short duct 130 through the opening 123 and the rear port of the air guide short duct 130, and then is discharged through the front port of the air guide short duct 130.

[0118] like Figure 6 , Figure 7 as well as Fig. 9 As shown in part (a), the rear port of the air guide short tube 130 and the opening 123 can be completely consistent in diameter, and the rear port of the air guide short tube 130 and the inner wall of the opening 123 can be aligned. At this time, the rear port of the air guide short tube 130 and the opening 123 can be regarded as the same opening.

[0119] Optionally, in other implementations, the diameter of the rear port of the air guide short pipe 130 may also be larger than the diameter of the opening 123, so as to maximize the cross-sectional area of ​​the pipe and ensure that the heat dissipation performance of the fan 100 is not affected.

[0120] like Figure 8 As shown in part (a) of FIG. 1 , the cross-sectional area of ​​the air guide short tube 130 is greater than or equal to the cross-sectional area of ​​the air guide channel 116. In other words, the diameter of the air guide short tube 130 is greater than the diameter of the air guide channel 116, and the inner contour of the air guide short tube 130 is greater than the inner contour of the air guide channel 116. Through the above arrangement, the adverse effect on the heat dissipation performance of the fan 100 caused by the arrangement of the air guide short tube 130 can be avoided or reduced.

[0121] In some cases, considering that the cross-sectional areas of the air guide short duct 130 and the air guide channel 116 may change in the air flow direction, the cross-sectional area of ​​the aforementioned air guide short duct 130 is greater than or equal to the cross-sectional area of ​​the air guide channel 116, which means that the minimum cross-sectional area of ​​the air guide short duct 130 is greater than or equal to the maximum cross-sectional area of ​​the air guide channel 116, thereby reliably ensuring that the heat dissipation performance of the fan 100 is not affected.

[0122] Optionally, the air guide short pipe 130 and the fan bracket 120 can be made into an integrated structure through an integrated molding process, so that the noise reduction structure has a strong mechanical strength and is conducive to reducing production costs. For example, the integrated molding process can be injection molding, 3D printing or powder metallurgy.

[0123] Optionally, in other implementations, the short air guide tube 130 and the fan bracket 120 may also be two independent components, and the two may be connected into an integrated structure by bonding, snap-fitting, or screwing.

[0124] Optionally, a reinforcing rib 140 is provided between the air guide short tube 130 and the fan bracket 120. By providing the reinforcing rib 140, the connection strength between the air guide short tube 130 and the fan bracket 120 can be improved, ensuring that the noise reduction structure as a whole has sufficient mechanical strength.

[0125] like Figure 6-Figure 9 As shown, a plurality of reinforcing ribs 140 may be provided and spaced apart on the outer periphery of the air guide short tube 130 . For example, two reinforcing ribs 140 are provided at each of the four corners of the side panel 122 . The two reinforcing ribs 140 are spaced apart and arranged in parallel, and the two ends are fixedly connected to the outer wall surface of the air guide short tube 130 and the outer surface of the side panel 122 , respectively.

[0126] Fig.12 yes Figure 6 A partial enlarged view of part A in the figure. Figure 6 , Fig. 9 Part (b) of Fig.12 As shown, in the embodiment of the present application, the caliber of the front port gradually decreases in the direction from the front port to the rear port.

[0127] While the air guide short pipe 130 plays a modal cutoff role and reduces the sound pressure amplitude, it also has a negative effect, which is to increase the unevenness of the airflow at the air inlet end of the fan 100, that is, to increase the irregularity of the airflow. Therefore, the present application sets the front port to gradually reduce the caliber so that the front port can optimize the airflow uniformity, thereby alleviating the interference of the front end to the air intake airflow, avoiding the occurrence of abnormal tones, and obtaining noise reduction benefits.

[0128] Here, the caliber gradually decreases, which can be a smooth transition to a smaller size (see Fig.13 ), or it can be a step-by-step gradual decrease (see Figure 6 or Fig. 9 ), or it may be a combination of the above two methods. The present application does not limit the specific implementation method of "gradually reducing the aperture". For example, the front port can be constructed into (including) any shape or structure, as long as the condition of "gradually reducing the aperture" can be met.

[0129] Optionally, in the direction from the front port to the rear port, the caliber of the front port gradually decreases until it finally becomes the same as the caliber of the air guide short duct.

[0130] Furthermore, if Figure 6 , Fig. 9 Part (b) of Fig.12 As shown, in the embodiment of the present application, the front port of the short air guide tube 130 includes a front end surface 131 that is stepped and gradually concave.

[0131] Specifically, in the embodiment of the present application, the air guide short tube 130 has a certain wall thickness, and the front end face 131 of the air guide short tube 130 is not a plane, but is composed of multiple (for example, 2, 3 or 4) annular faces of different heights. The height here refers to the distance relative to the rear end face or the relative side plate 122. Due to the different heights, multiple annular faces that are connected in sequence together form a stepped structure and gradually concave toward the inside of the short tube, that is, the closer the annular face is to the rear end face of the short tube. Correspondingly, the smaller the diameter of the annular face is, that is, the outermost (i.e., the front end) annular face has the largest diameter, and the innermost (i.e., the rear end) annular face has the smallest diameter, and the diameter of the innermost annular face is equal to the inner diameter of the air guide short tube 130.

[0132] While the air guide short tube 130 plays a modal cutoff role and reduces the sound pressure amplitude, it also has a negative impact, which is that it increases the unevenness of the airflow at the air inlet end of the fan 100, that is, it increases the irregularity of the airflow. Therefore, 2-3 layers of stepped features can be added to a certain thickness space of the air inlet end face (i.e., the front end face 131), that is, the front end face 131 is set to be composed of multiple annular surfaces, and the multiple annular surfaces are stepped and gradually concave. The multiple annular surfaces can cut the airflow (such as vortex), so as to alleviate the interference of the front end face 131 on the intake airflow, reduce the velocity gradient, and increase the uniformity of the airflow, thereby avoiding the occurrence of abnormal tones. After actual measurement and verification, the stepped front end face 131 does have the effect of reducing the noise of the fan unit.

[0133] Optionally, in other implementations, the stepped and gradually concave front end surface may also be replaced by a bell mouth. Fig.13 1 is a schematic diagram showing that the front end of the air guide short pipe 130 includes a bell mouth structure 132. Fig.13 As shown, the front port of the air guide short pipe 130 includes a bell-mouth structure 132, or in other words, the front port of the air guide short pipe 130 is a bell-mouth structure, and the diameter of the bell-mouth structure 132 gradually decreases in the direction from the front port to the rear port until it is equal to the diameter of the subsequent air guide short pipe 130. Through the above arrangement, the uniformity of the airflow at the air intake end can also be increased and optimized, the occurrence of abnormal tones can be avoided, and noise reduction benefits can be obtained.

[0134] Fig.14 : is a top view of a specific example of the noise reduction structure provided in the embodiment of the present application. As a specific example, take a 40*40*10mm axial flow cooling fan as an example, Fig.14The relevant dimensional features of the noise reduction structure applied to the fan are shown, namely, the cross-sectional shape of the short air guide tube 130 is an octagon, including 4 long sides and 4 short sides, the length of the 4 long sides is 18 mm, the length of the 4 short sides is 14.1 mm, the long sides and the short sides are arranged in sequence at intervals, and the length of the short air guide tube 130 is 10 mm, which can achieve a noise reduction of more than 2dB for the fan unit, and has been verified by multiple rounds of axial flow fans of various sizes, with fan specifications ranging from 40mm to 80mm, and the noise reduction effect is consistent.

[0135] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any person skilled in the art who is familiar with the present technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A noise reduction structure, characterized in that: include: An air guide short tube (130), wherein the cross-section of the inner cavity of the air guide short tube (130) is polygonal, and the air guide short tube (130) has a front port and a rear port that are interconnected, and the rear port is used to communicate with an air inlet or an air outlet of a fan (100), so that the air guide short tube (130) can guide and reduce the noise of the air inlet or air outlet of the fan (100).

2. The noise reduction structure according to claim 1, characterized in that: In the direction from the front port to the rear port, the diameter of the front port gradually decreases.

3. The noise reduction structure according to claim 2, characterized in that: The front port comprises a front end surface (131) which is stepped and gradually concave.

4. The noise reduction structure according to claim 2, characterized in that: The front port comprises a bell-mouth structure (132), and the diameter of the bell-mouth structure (132) gradually decreases in the direction from the front port to the rear port.

5. The noise reduction structure according to any one of claims 1 to 4, characterized in that: The fan (100) is an axial flow fan, and the cross-sectional area of ​​the air guide short pipe (130) is greater than or equal to the cross-sectional area of ​​the air guide channel (116) of the fan (100).

6. The noise reduction structure according to any one of claims 1 to 5, characterized in that: The polygon is a hexagon, an octagon or a dodecagon.

7. The noise reduction structure according to any one of claims 1 to 5, characterized in that: The polygon is an octagon, the fan (100) is an axial flow fan, and the cross-sectional shape of the air guide channel (116) of the fan (100) includes four straight sides and four arcuate sides, and any two adjacent straight sides are connected by one arcuate side.

8. The noise reduction structure according to any one of claims 1 to 7, characterized in that: The noise reduction structure also includes: A fan bracket (120), wherein the fan bracket (120) is provided with an opening (123), wherein the opening (123) constitutes the air inlet or the air outlet, and the opening (123) is sealed and butted with the rear port.

9. The noise reduction structure according to claim 8, characterized in that: The fan bracket (120) comprises an annular frame (121) and a side plate (122); the annular frame (121) is used to be sleeved on the outer periphery of the fan body (110) of the fan (100); the side plate (122) covers a port of the annular frame (121); and the opening (123) is formed on the side plate (122).

10. The noise reduction structure according to claim 8 or 9, characterized in that: The short air guide tube (130) and the fan bracket (120) are formed into an integral structure through an integral molding process.

11. The noise reduction structure according to any one of claims 8 to 10, characterized in that: A reinforcing rib (140) is provided between the short air guide tube (130) and the fan bracket (120).

12. The noise reduction structure according to any one of claims 1 to 11, characterized in that: The length of the short air guide tube (130) is 8 to 50 mm.

13. A fan, characterized in that: include: The noise reduction structure according to any one of claims 1 to 12.

14. An electronic device, characterized in that: include: A heating element (200) and a fan as claimed in claim 13, wherein the fan is used to dissipate heat for the heating element (200).

15. The electronic device according to claim 14, characterized in that: The electronic device is a server, a smart host, a whole-house central control host, a router, a user-end device, a base station, a mobile terminal, a desktop computer, a robot, a machine tool, a semiconductor processing equipment, a printer, a vacuum cleaner, a hair dryer or a game console.

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