Noise reduction garden fan

Abstract

The invention discloses a noise reduction garden fan, belongs to the field of garden fans, solves the problems that a noise reduction assembly is complex in structure and tedious in installation, and adopts the technical scheme that the noise reduction garden fan mainly comprises a machine shell and an airflow channel connected to the front end of the machine shell, and a driving motor used for forming airflow and a fan are arranged in the airflow channel; the inner wall of the air flow channel is provided with a noise reduction area which is annularly distributed, orthographic projections of blades of the fan on the inner wall of the air flow channel are located in the noise reduction area, a plurality of noise reduction hole grooves are formed in the noise reduction area, the air inlet end of the air flow channel is in a horn shape, and a plurality of continuous noise reduction steps are arranged on the inner wall of the air inlet end. The structure of the airflow channel can be simplified while the noise reduction effect is achieved.

Description

Technical Field

[0001] The present invention discloses a noise-reducing garden blower, belonging to the technical field of garden blowers. Background Art

[0002] A garden blower is a gardening tool that can use air flow to help users blow grass clippings, fallen leaves, etc., so as to clean a courtyard or a garden.

[0003] During the use of a garden blower, a driving motor is used as a driving device, and drives a fan to rotate at a high speed, thereby forming a high-speed air flow in the housing. The high-speed rotation of the blades will generate eddy currents in the air flow channel. In addition, the blades will cut the air flow and generate friction with the air flow, and the air flow will also generate friction with the inner wall of the air flow channel, thereby generating relatively large noise and affecting the user experience.

[0004] For example, a garden blower disclosed in Patent CN211975528U includes a housing assembly, a sound-absorbing hole area, and a sound-absorbing component. The sound-absorbing hole area is formed by a plurality of sound-absorbing holes distributed in a ring along the air flow channel. The sound-absorbing holes are opened through the side wall of the duct. There is a preset distance between the sound-absorbing hole area and the blade area of the fan blades facing the duct. At least part of the sound-absorbing component covers the outer wall of the sound-absorbing hole area, so as to achieve a noise reduction effect through the sound-absorbing component.

[0005] However, in the above patent, the sound-absorbing component is fixed on the outer wall of the duct, which will affect the overall diameter of the duct, resulting in an overly large overall volume of the duct. In addition, since the sound-absorbing holes penetrate the side wall of the duct, in order to prevent the air flow in the duct from leaking to the outside of the duct through the sound-absorbing holes, the sound-absorbing component needs to seal all the sound-absorbing holes. Therefore, the structure of the sound-absorbing component is relatively complex and the installation is rather cumbersome. In addition, after long-term use, air leakage is likely to occur, which will affect the blowing efficiency of the garden blower. Summary of the Invention

[0006] The purpose of the present invention is to solve the problem that the structure of the sound-absorbing component is relatively complex and the installation is rather cumbersome. For this reason, a noise-reducing garden blower is provided, which can simplify the structure of the air flow channel while having a noise reduction effect.

[0007] To solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A noise-reducing garden blower includes a housing, an air flow channel connected to the front end of the housing, a fan disposed in the air flow channel for forming an air flow, and a driving motor disposed in the air flow channel or the housing for driving the fan. The inner wall of the air flow channel is provided with a sound-absorbing area distributed in a ring. The orthographic projection of the fan blades on the inner wall of the air flow channel is within the sound-absorbing area, and a plurality of sound-absorbing hole grooves are provided in the sound-absorbing area.

[0009] The beneficial effects of adopting the present invention are as follows:

[0010] In the present invention, a sound-absorbing area is provided on the inner wall of the air flow channel. The sound-absorbing area is annularly distributed on the outer peripheral side of the blade. A plurality of sound-absorbing holes and grooves are provided in the sound-absorbing area. When the blade of the fan rotates to generate air flow, noise will also be generated. The noise propagates in the air flow channel in the form of sound waves. Part of the noise will pass through the air flow channel and propagate to the outside of the casing. When the sound wave enters the sound-absorbing holes and grooves, part of the energy of the sound wave will be absorbed and dispersed by the groove walls of the sound-absorbing holes and grooves. The concave structure of the sound-absorbing holes and grooves can increase the contact area between the sound wave and the groove walls, thereby improving the efficiency of the sound-absorbing holes and grooves in absorbing sound waves. In addition, the air molecules in the sound-absorbing holes and grooves will also interact with the sound wave, converting part of the energy of the sound wave into heat energy, further consuming the energy of the sound wave, which helps to significantly reduce the intensity and frequency of the noise and achieve a better noise reduction effect. Secondly, since the fan rotates at a high speed in the air flow channel to generate a stable air flow, and the noise is mainly generated by the rotation of the fan, setting the sound-absorbing area on the outer peripheral side of the blade can improve the absorption efficiency of the sound-absorbing holes and grooves in absorbing sound waves, which helps to improve the noise reduction effect of the sound-absorbing area.

[0011] Preferably, the sound-absorbing holes and grooves do not completely penetrate the side wall of the air flow channel. By adopting the foregoing technical solution, the sound-absorbing holes and grooves do not completely penetrate the side wall of the air flow channel, so the overall structure of the air flow channel remains intact, and the air flow in the air flow channel will not leak to the outside from the sound-absorbing holes and grooves. Therefore, the design of the sound-absorbing holes and grooves is not likely to affect the blowing effect of the garden blower, and the air flow channel does not need to additionally fix sound-absorbing parts, keeping the overall structure of the air flow channel simple and reducing the assembly difficulty of the air flow channel.

[0012] Preferably, the air flow channel sequentially includes a collector, a diffuser barrel and an air duct along the air flow direction. The fan is located in the collector, and the sound-absorbing area is provided on the inner wall of the collector.

[0013] Preferably, the shape of the orifice of the sound-absorbing holes and grooves is triangular, and the sound-absorbing holes and grooves are recessed along the radial direction of the air flow channel.

[0014] Preferably, the shape of the sound-absorbing holes and grooves is a triangular prism, and the apex angle of the sound-absorbing holes and grooves is an acute angle, with the apex angle facing the end of the collector away from the air duct. By adopting the foregoing technical solution, since the end away from the air duct is the air inlet end, in order to allow more air flow to enter the collector, the inner diameter of the air inlet end of the collector is the largest. When manufacturing the collector, it will be more convenient and simple to demold from the air inlet end of the collector. The sound-absorbing holes and grooves adopt a triangular prism structure, and the apex angle of the triangular prism faces the air inlet end. During the demolding process, the contact area between the sound-absorbing holes and grooves and the mold can be reduced, thereby reducing the friction force between the sound-absorbing holes and grooves and the mold, making it easier for the collector to be removed from the mold and reducing the demolding difficulty of the collector.

[0015] Preferably, the depth of the sound-absorbing hole groove is H, and 0.3 mm ≤ H ≤ 1 mm. By adopting the foregoing technical solution, the area of the side wall of the sound-absorbing hole groove can be increased, so that the sound-absorbing hole groove can absorb more sound waves, which helps to improve the sound absorption efficiency of the sound-absorbing hole groove, can enhance the noise reduction effect of the sound-absorbing hole groove, make the noise generated during the use of the garden fan smaller, and helps to improve the user experience; when H < 0.3 mm, the depth of the sound-absorbing hole groove is relatively shallow, the side wall area of the sound-absorbing hole groove is small, and after the sound wave enters the sound-absorbing hole groove, the sound wave that the groove wall can absorb is small, which will reduce the noise reduction effect of the sound-absorbing hole groove; when H > 1 mm, the depth of the sound-absorbing hole groove is too large, which easily causes the wall surface of the air flow channel where the sound-absorbing hole groove is located to be too thin, and will reduce the strength of the side wall of the air flow channel, making the air flow channel easily damaged.

[0016] Preferably, the air flow channel sequentially includes a collector, a diffuser barrel and an air duct along the air flow direction. One end of the collector away from the diffuser barrel is the air inlet end, the air inlet end is in a horn shape, and a plurality of continuous sound-absorbing steps are provided on the inner wall of the air inlet end. By adopting the foregoing technical solution, during the rotation of the fan, the air flow will enter the air flow channel through the air inlet end. During this process, the turning of the air flow at the air inlet end is relatively large, and a large amount of noise will be generated at the air inlet end. When the sound wave formed by the noise encounters the sound-absorbing step, phenomena such as reflection and refraction will occur, thereby changing the propagation direction of the sound wave, and then helping to guide the sound wave to different directions, reducing the superposition and enhancement of the sound wave in a specific direction, and further reducing the intensity and influence range of the noise; in addition, the sound-absorbing step can also increase the area of the air inlet end, increase the contact area between the sound wave and the air inlet end, and then can improve the sound absorption efficiency of the air inlet end to the sound wave, which helps to reduce the intensity of the noise.

[0017] Preferably, the sound-absorbing steps are arranged in a circumferential direction around the inner wall of the collector. The sound-absorbing step has a first wall surface and a second wall surface, wherein the first wall surface is perpendicular to the second wall surface, the first wall surface is parallel to the axial direction of the collector, and the second wall surface is parallel to the radial direction of the collector; or, an obtuse angle is formed between the first wall surface and the second wall surface. By adopting the foregoing technical solution, the first wall surface and the second wall surface are perpendicular to each other, which can form a reflecting surface. After the sound wave encounters the sound-absorbing step, the number of reflections and refractions of the sound wave between the first wall surface and the second wall surface can be increased, and then the sound wave is dispersed to different directions, reducing the superposition and enhancement of the sound wave in a specific direction, and further reducing the intensity and influence range of the noise.

[0018] Preferably, a transition curved surface is provided at the connection between the first wall surface and the second wall surface.

[0019] Preferably, the air flow channel sequentially includes a collector, a diffuser tube, and an air duct along the air flow direction. A fixing frame for fixing the driving motor is provided in the middle of the diffuser tube. A plurality of guide vanes are provided on the outer peripheral side of the fixing frame. The guide vanes extend towards the inner wall of the diffuser tube and are fixedly connected to the diffuser tube. A plurality of sound-absorbing sawteeth are provided on the side of the guide vane away from the collector, and the width of the sound-absorbing sawteeth gradually decreases in the air flow direction.

[0020] Preferably, the air flow channel sequentially includes a collector, a diffuser tube, and an air duct along the air flow direction. The air duct is provided with an air outlet at one end away from the collector. A plurality of sound-absorbing sawteeth are provided on the edge of the air outlet along the circumferential direction of the air outlet. The width of the sound-absorbing sawteeth gradually decreases in the air flow direction. With the foregoing technical solution, in the prior art, the edge of the air outlet of the air flow channel is flat. Since the air flow velocity outside the air flow channel is gentle, when the high-speed air flow blows out from the air outlet to the outside, eddy currents will be formed between the air flow and the outside air, and thus relatively large noise will be generated at the air outlet. In this embodiment, the sound-absorbing sawteeth can split the eddy currents formed at the air outlet into laminar flows, thereby reducing the formation of eddy currents at the air outlet, and thus achieving the effects of stabilizing the air flow and reducing noise.

[0021] Preferably, the end of the sound-absorbing sawtooth is an arc surface; or, the end contour of the sound-absorbing sawtooth is an owl wing contour, and the polynomial fitting formula of the end contour of the sound-absorbing sawtooth is:

[0022] Y = 0.123067 + 3.68671*X 2 -1.1723431*X 3 +0.33178*X 4 -0.033697*X 5 ;

[0023] The range of each coefficient in the fitting formula is ±50%.

[0024] Other features and advantages of the present invention will be disclosed in detail in the following specific embodiments and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The following further describes the present invention with reference to the drawings:

[0026] Figure 1 is a schematic structural diagram of a noise-reducing garden blower of the present invention;

[0027] Figure 2 is an exploded view of a noise-reducing garden blower of the present invention;

[0028] Figure 3 is a sectional view of a noise-reducing garden blower of the present invention;

[0029] Figure 4 is Figure 3 a partial enlarged view of part A in

[0030] Figure 5 a schematic structural view of an air collector in a noise-reducing garden blower of the present invention;

[0031] Figure 6 a sectional view of an air collector in a noise-reducing garden blower of the present invention;

[0032] Figure 7 is Figure 6 a partial enlarged view of part B in

[0033] Figure 8 a schematic structural view of a diffuser tube in a noise-reducing garden blower of the present invention;

[0034] Figure 9 a schematic structural view of an air outlet nozzle in a noise-reducing garden blower of the present invention;

[0035] Figure 10 a fitting diagram of the end contour of a sound-absorbing sawtooth in a noise-reducing garden blower of the present invention.

[0036] Reference numerals: 1, housing; 2, air flow channel; 21, air collector; 211, air inlet end; 212, sound-absorbing area; 213, sound-absorbing hole groove; 214, sound-absorbing step; 2141, first wall surface; 2142, second wall surface; 22, diffuser tube; 221, fixing bracket; 222, guide plate; 23, air duct; 24, air outlet nozzle; 241, sound-absorbing sawtooth; 25, drive motor; 26, fan; 261, blade; 3, battery pack. Detailed implementation manners

[0037] The technical solutions of the embodiments of the present invention will be explained and described below with reference to the accompanying drawings of the embodiments of the present invention. However, the following embodiments are only the preferred embodiments of the present invention and not all of them. Based on the embodiments in the implementation manners, other embodiments obtained by those skilled in the art without creative efforts all fall within the protection scope of the present invention.

[0038] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention 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 construed as a limitation to the present invention.

[0039] In the present invention, unless otherwise clearly specified and defined, terms such as "installed", "connected", "linked", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be a direct connection or an indirect connection through an intermediate medium, and it may be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0040] As Figures 1 to 10 shown, this embodiment shows a noise-reducing garden blower, including a housing 1, an air flow channel 2 connected to the front end of the housing 1, a fan 26 disposed in the air flow channel 2 for forming an air flow, and a drive motor 25 disposed in the air flow channel 2 and for driving the fan 26. A battery pack 3 for supplying power to the drive motor 25 is detachably installed on the housing 1. The air flow channel 2 has an air inlet end 211 inside the housing 1 and an air outlet end extending outside the housing 1. When the drive motor 25 starts to drive the fan 26 to rotate, the air outside the garden blower enters the housing 1 and enters the air flow channel 2 through the air inlet end 211. Under the action of the fan 26, an air flow with a relatively large flow rate is formed and finally blown out from the air outlet end of the air flow channel 2 to achieve the effect of blowing grass clippings, fallen leaves, etc.

[0041] Of course, it can be understood that in other embodiments, the drive motor 25 may also be disposed outside the air flow channel 2 and inside the housing 1.

[0042] As Figure 3 and Figure 4As shown in the figure, in this embodiment, the inner wall of the air flow channel 2 is provided with a sound absorption area 212 distributed in a ring shape. The orthographic projection of the blade 261 of the fan 26 on the inner wall of the air flow channel 2 is within the sound absorption area 212, that is, the sound absorption area 212 surrounds the outer peripheral side of the blade 261. A plurality of sound absorption hole grooves 213 recessed along the radial direction of the air flow channel 2 are provided in the sound absorption area 212. The sound absorption hole grooves 213 do not completely penetrate the side wall of the air flow channel 2. During the operation of the garden blower, the drive motor 25 drives the fan 26 to rotate rapidly to generate air flow. During the rotation of the fan 26, the blade 261 will rub against the air flow, and the air flow will also form eddies at the blade 261, thereby generating relatively large noise. The noise generated by the garden blower is mainly concentrated in the area where the blade 261 is located. After the noise is formed, it will propagate in the air flow channel 2 in the form of sound waves. The sound absorption area 212 is arranged around the outer peripheral side of the blade 261, so that more sound waves will enter the sound absorption area 212 during the propagation process, thereby fully improving the utilization rate of the sound absorption area 212. When the sound waves enter the sound absorption hole grooves 213, part of the energy of the sound waves will be absorbed and dispersed by the groove walls of the sound absorption hole grooves 213. The concave structure of the sound absorption hole grooves 213 can increase the contact area between the sound waves and the groove walls, thereby improving the efficiency of the sound absorption hole grooves 213 in absorbing sound waves. In addition, the air molecules in the sound absorption hole grooves 213 will also interact with the sound waves, converting part of the energy of the sound waves into heat energy, further consuming the energy of the sound waves, which helps to significantly reduce the intensity and frequency of the noise and achieve a better noise reduction effect. Secondly, the sound absorption hole grooves 213 do not completely penetrate the side wall of the air flow channel 2, so the overall structure of the air flow channel 2 remains intact, and the air flow in the air flow channel 2 will not leak from the outside of the sound absorption hole grooves 213. Therefore, the design of the sound absorption hole grooves 213 is not likely to affect the blowing effect of the garden blower, and the air flow channel 2 does not need to be additionally fixed with sound absorption components, making the overall structure of the air flow channel 2 simple and also reducing the assembly difficulty of the air flow channel 2.

[0043] As Figure 2As shown in the figure, in this embodiment, the air flow channel 2 sequentially includes a collector 21, a diffuser 22, and a duct 23 along the air flow direction. The inlet end 211 of the air flow channel 2 is formed at one end of the collector 21 away from the duct 23, and the outlet end of the air flow channel 2 is formed at one end of the duct 23 away from the collector 21. The collector 21 is fixed inside the housing 1, and the inlet end 211 of the collector 21 is a flared opening. A pressure ring is also provided inside the housing 1. The pressure ring wraps the edge of the inlet end 211 and is connected to the housing 1, thereby realizing the fixed connection between the collector 21 and the housing 1. A fixing bracket 221 for fixing the driving motor 25 is provided in the middle of the diffuser 22. The output end of the driving motor 25 extends towards the collector 21. The fan 26 is fixedly connected to the driving motor 25, and the fan 26 is located inside the collector 21. A sound-absorbing area 212 is also provided on the inner wall of the collector 21. The sound-absorbing area 212 is annularly distributed along the circumferential direction of the inner wall of the collector 21. A number of sound-absorbing holes 213 are provided in the sound-absorbing area 212. The sound-absorbing holes 213 are evenly spaced in the sound-absorbing area 212. The depth of the sound-absorbing holes 213 recessed along the radial direction of the collector 21 is H, and 0.3 mm ≤ H ≤ 1 mm. Using the above depth can increase the side wall area of the sound-absorbing holes 213, enabling the sound-absorbing holes 213 to absorb more sound waves, which helps to improve the absorption efficiency of the sound-absorbing holes 213 for sound waves, can enhance the noise reduction effect of the sound-absorbing holes 213, making the noise generated during the use of the garden blower smaller, and helping to improve the user experience. In addition, the sound-absorbing holes 213 are evenly spaced, which can make the sound absorption effect of the sound-absorbing area 212 more uniform, avoiding the possibility of excessive sound wave intensity at one place in the collector 21, and helping to improve the noise reduction effect of the sound-absorbing area 212.

[0044] When H < 0.3 mm, the depth of the sound-absorbing holes 213 is relatively shallow, and the side wall area of the sound-absorbing holes 213 is small. After the sound waves enter the sound-absorbing holes 213, the sound waves that the groove walls can absorb are small, which will reduce the noise reduction effect of the sound-absorbing holes 213. When H > 1 mm, the depth of the sound-absorbing holes 213 is too large, which easily causes the wall surface of the air flow channel 2 where the sound-absorbing holes 213 are located to be too thin, reducing the strength of the side wall of the air flow channel 2 and making the air flow channel 2 easily damaged.

[0045] Such as Figure 4 and Figure 5As shown, in this embodiment, the notch shape of the sound-absorbing hole groove 213 is an isosceles triangle. The sound-absorbing hole groove 213 is recessed along the radial direction of the air flow channel 2, so that the shape of the sound-absorbing hole groove 213 is a triangular prism. The apex angle of the sound-absorbing hole groove 213 is an acute angle, and the angle range of the apex angle is 15° to 25°. The distance from the apex angle to the bottom edge is h, and 1.5 mm ≤ h ≤ 8 mm. The apex angle faces the end of the air collector 21 away from the air duct 23. That is, in the air flow direction, the width of the sound-absorbing hole groove 213 gradually increases. In this embodiment, the air collector 21 is made by injection molding. After injection molding, demolding is required. The diameter of the air collector 21 at the air inlet end 211 is larger. Therefore, it is easier to demold from the air inlet end 211. During the demolding process, the groove wall of the sound-absorbing hole groove 213 will generate friction with the mold, which will hinder the demolding of the air collector 21. In this embodiment, the apex angle of the sound-absorbing hole groove 213 faces the air inlet end 211, which can reduce the contact area between the sound-absorbing hole groove 213 and the mold, and then reduce the friction between the sound-absorbing hole groove 213 and the mold, making it easier for the air collector 21 to be demolded from the mold and reducing the demolding difficulty of the air collector 21.

[0046] When the angle of the apex angle is less than 15°, the apex angle of the sound-absorbing hole groove 213 is too narrow, which will reduce the sound wave entering the sound-absorbing hole groove 213 and reduce the noise reduction effect of the sound-absorbing hole groove 213. When the angle of the apex angle is greater than 25°, the area of the apex angle of the sound-absorbing hole groove 213 facing the air inlet end 211 will increase, which will increase the contact area between the sound-absorbing hole groove 213 and the mold during the demolding process, increase the friction between the sound-absorbing hole groove 213 and the mold, and make the demolding of the air collector 21 more difficult.

[0047] Of course, it can be understood that in other embodiments, the notch shape of the sound-absorbing hole groove 213 can also be other shapes such as circular, rectangular or polygonal.

[0048] To further improve the noise reduction effect of the garden fan, such as Figure 6 and Figure 7As shown in the figure, in this embodiment, the inner wall of the air inlet end 211 is provided with a plurality of sound-absorbing steps 214. Each sound-absorbing step 214 is arranged in a ring shape along the circumferential direction of the air inlet end 211. A plurality of sound-absorbing steps 214 are arranged continuously along the axial direction of the air inlet end 211. The sound-absorbing step 214 includes a first wall surface 2141 and a second wall surface 2142 that are perpendicular to each other. Among them, the first wall surface 2141 is parallel to the axial direction of the air collector 21, and the second wall surface 2142 is parallel to the radial direction of the air collector 21. During the rotation of the fan 26, the air flow will enter the air flow channel 2 through the air inlet end 211 under the action of the fan 26. Since the air inlet end 211 is a flared opening, it can expand the range of air flow absorbed by the air inlet end. During this process, the turning of the air flow at the air inlet end 211 is relatively large, and a large amount of noise will be generated at the air inlet end 211. When the sound wave formed by the noise encounters the sound-absorbing step 214, phenomena such as reflection and refraction will occur, thereby changing the propagation direction of the sound wave, and then helping to guide the sound wave to different directions, reducing the superposition and enhancement of the sound wave in a specific direction, and further reducing the intensity and influence range of the noise; in addition, the sound-absorbing step 214 can also increase the area of the air inlet end 211, increase the contact area between the sound wave and the air inlet end 211, and then improve the absorption efficiency of the air inlet end 211 for the sound wave, which helps to reduce the intensity of the noise.

[0049] As Figure 7 shown in the figure, in this embodiment, the length of the first wall surface 2141 in the axial direction of the air collector 21 is L, and 1 mm ≤ L ≤ 5 mm; the width of the second wall surface 2142 in the radial direction of the air collector 21 is D, and 0.3 mm ≤ D ≤ 1.5 mm. The sound-absorbing step 214 adopts the above structure, which can improve the absorption efficiency of the sound-absorbing step 214 for the sound wave while reducing the influence of the sound-absorbing step 214 on the air flow; when D < 0.3 mm, the width of the second wall surface 2142 is relatively small, which will reduce the contact area between the sound wave and the second wall surface 2142, and then reduce the absorption efficiency of the second wall surface 2142 for the sound wave, and reduce the noise reduction effect of the sound-absorbing step 214; when D > 1.5 mm, the width of the second wall surface 2142 is too large. When the air flow flows towards the second wall surface 2142, the second wall surface 2142 will obstruct the air flow, easily cause energy loss of the air flow, reduce the flow velocity of the air flow, and thus affect the blowing effect of the garden blower.

[0050] Of course, it can be understood that in other embodiments, the first wall surface 2141 and the second wall surface 2142 may also be in an obtuse angle structure, which can reduce the resistance of the sound-absorbing step 214 to the air flow entering the air collector 21, reduce the energy loss of the air flow, help maintain the flow velocity of the air flow, and make the garden blower have a better blowing effect.

[0051] Of course, it can be understood that in other embodiments, the connection between the first wall surface 2141 and the second wall surface 2142 has a transition surface, which can be drawn using a spline curve, thereby increasing the area of the sound-absorbing step 214 and contributing to improving the noise reduction effect of the sound-absorbing step 214.

[0052] As Figure 8 shown, in this embodiment, a fixing bracket 221 for fixing the driving motor 25 is provided in the middle of the air diffuser 22. A plurality of guide vanes 222 are provided on the outer peripheral side of the fixing bracket 221. The guide vanes 222 extend towards the inner wall of the air diffuser 22 and are fixedly connected to the air diffuser 22. A plurality of sound-absorbing sawteeth 241 are provided on the side of the guide vanes 222 away from the air collector 21. The fixing bracket 221 is arranged in the middle of the air diffuser 22 so that the gap between the fixing bracket 221 and the air diffuser 22 remains uniform, enabling the air flow to be stable and uniform after passing through the fixing bracket 221. In addition, the guide vanes 222 can also guide the air flow, reducing the eddy currents generated in the air diffuser 22, making the air flow more stable, contributing to maintaining the air flow velocity, enabling the garden blower to have a better blowing effect, and at the same time reducing the noise generated by the air flow in the air diffuser 22, contributing to improving the user experience; secondly, by providing the sound-absorbing sawteeth 241 at the ends of the guide vanes 222, the eddy currents formed at the ends of the guide vanes 222 can also be split into laminar flows, thereby reducing the formation of eddy currents at the ends of the guide vanes 222, and thus achieving the effects of stabilizing the air flow and reducing noise.

[0053] As Figure 9 shown, in this embodiment, an air outlet nozzle 24 is installed at the air outlet end of the air duct 23. A plurality of sound-absorbing sawteeth 241 distributed axially along the air outlet nozzle 24 are provided at the end of the air outlet nozzle 24 away from the air duct 23. The width of the sound-absorbing sawteeth 241 gradually decreases in the air flow direction, that is, the ends of the sound-absorbing sawteeth 241 form tips. A gap is formed between adjacent two sound-absorbing sawteeth 241, and the width of the gap gradually increases in the air flow direction. In the prior art, the edge of the air outlet end of the air flow channel 2 is flat. Since the air flow velocity outside the air flow channel 2 is gentle, when the high-speed air flow blows out from the air outlet end to the outside, eddy currents will be formed between the air flow and the outside air, and thus a large amount of noise will be generated at the air outlet end. In this embodiment, the sound-absorbing sawteeth 241 can split the eddy currents formed at the air outlet end into laminar flows, thereby reducing the formation of eddy currents at the air outlet end, and thus achieving the effects of stabilizing the air flow and reducing noise.

[0054] As Figure 9 and Figure 10 shown, in this embodiment, the number of the sound-absorbing sawteeth 241 at the end of the air outlet nozzle 24 is 10 to 30. The end contour of the sound-absorbing sawteeth 241 is an imitation of the owl wing contour. The polynomial fitting formula of the end contour of the sound-absorbing sawteeth 241 is:

[0055] Y = 0.123067 + 3.68671*X 2 -1.1723431*X 3 +0.33178*X 4 -0.033697*X 5 ;

[0056] The range of the coefficients of each term in the fitting formula is ±50%.

[0057] Of course, it can be understood that in other embodiments, the end of the sound-absorbing serration 241 can also be an arc surface.

[0058] As described above, the above is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that the present invention includes but is not limited to the content described in the drawings and the above specific implementation manner. Any modification that does not deviate from the functional and structural principles of the present invention will be included in the scope of the claims.

Claims

1. A noise-reducing garden fan, comprising a housing (1), an airflow channel (2) connected to the front end of the housing (1), a fan (26) arranged in the airflow channel (2) for forming an airflow, and a drive motor (25) arranged in the airflow channel (2) or the housing (1) and for driving the fan (26), characterized in that: The inner wall of the airflow channel (2) is provided with a sound-absorbing area (212) distributed in an annular shape, the orthographic projection of the blades (261) of the fan (26) on the inner wall of the airflow channel (2) is located in the sound-absorbing area (212), and a plurality of sound-absorbing holes (213) are provided in the sound-absorbing area (212).

2. A noise reduction garden fan according to claim 1, characterized in that: The muffler hole groove (213) does not completely penetrate the side wall of the air flow channel (2).

3. The noise reduction garden fan according to claim 1 is characterized in that: The air flow channel (2) comprises a collector (21), an air diffuser (22) and an air duct (23) in sequence along the air flow direction; the fan (26) is located in the collector (21); and the silencer zone (212) is arranged on the inner wall of the collector (21).

4. The noise reduction garden fan according to claim 1, characterized in that: The notch shape of the silencer hole groove (213) is triangular, and the silencer hole groove (213) is formed by being recessed radially along the airflow channel (2).

5. A noise reduction garden fan according to claim 4, characterized in that: The shape of the silencer hole groove (213) is a triangular prism, and the top angle of the silencer hole groove (213) is an acute angle, and the top angle faces the end of the collector (21) away from the air duct (23).

6. A noise reduction garden fan according to claim 4, characterized in that: The depth of the muffler hole groove (213) is H, and 0.3 mm ≤ H ≤ 1 mm.

7. The noise reduction garden fan according to claim 1, characterized in that: The air flow channel (2) comprises a flow collector (21), an air dispersion tube (22) and an air duct (23) in sequence along the air flow direction; the end of the flow collector (21) away from the air dispersion tube (22) is an air inlet end (211); the air inlet end (211) is trumpet-shaped; and a plurality of continuous sound-absorbing steps (214) are provided on the inner wall of the air inlet end (211).

8. The noise reduction garden fan according to claim 7, characterized in that: The silencer step (214) is arranged circumferentially along the inner wall of the collector (21), and the silencer step (214) has a first wall surface (2141) and a second wall surface (2142), wherein the first wall surface (2141) is perpendicular to the second wall surface (2142), the first wall surface (2141) is parallel to the axial direction of the collector (21), and the second wall surface (2142) is parallel to the radial direction of the collector (21); or, an obtuse angle is formed between the first wall surface and the second wall surface.

9. A noise-reducing garden fan according to claim 8, characterized in that: A transitional curved surface is provided at the connection between the first wall surface (2141) and the second wall surface (2142).

10. The noise reduction garden fan according to claim 1, characterized in that: The air flow channel (2) comprises a collector (21), an air dispersion tube (22) and an air duct (23) in sequence along the air flow direction; a fixing frame (221) for fixing a driving motor (25) is provided in the middle of the air dispersion tube (22); a plurality of guide plates (222) are provided on the outer peripheral side of the fixing frame (221); the guide plates (222) extend toward the inner wall of the air dispersion tube (22) and are fixedly connected to the air dispersion tube (22); a plurality of silencer saw teeth (241) are provided on a side of the guide plate (222) away from the collector (21); and the width of the silencer saw teeth (241) gradually decreases in the air flow direction.

11. The noise reduction garden fan according to claim 1, characterized in that: The air flow channel (2) comprises a flow collector (21), an air diffuser (22) and an air duct (23) in sequence along the air flow direction; one end of the air duct (23) away from the flow collector (21) is an air outlet end; a plurality of silencer saw teeth (241) distributed along the circumference of the air outlet end are provided at the edge of the air outlet end; the width of the silencer saw teeth (241) gradually decreases in the air flow direction.

12. A noise-reducing garden fan according to claim 10 or 11, characterized in that: The end of the noise-reducing sawtooth (241) is a curved surface; or, the end profile of the noise-reducing sawtooth (241) is an owl-wing-like profile, and the polynomial fitting formula of the end profile of the noise-reducing sawtooth (241) is: Y=0.123067+3.68671*X 2 -1.1723431*X 3 +0.33178*X 4 -0.033697*X 5 ; The range of each coefficient in the fitting formula is ±50%.

Images