Noise reduction garden fan

Abstract

The utility model 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 and a fan which are used for forming airflow 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 utility model is mainly used for reducing noise and simplifying the structure of the air flow channel at the same time.

Description

Technical Field

[0001] This utility model demonstrates a noise-reducing garden fan, belonging to the field of garden fan technology. Background Technology

[0002] A garden fan is a garden tool that uses airflow to help users blow away grass clippings, fallen leaves, etc., thereby cleaning the yard or garden.

[0003] Garden fans utilize a drive motor as a driving device during operation, which drives the fan to rotate at high speed, thereby creating a high-speed airflow within the casing. The high-speed rotation of the blades generates vortices within the airflow channel. Additionally, the blades cut and rub against the airflow, while the airflow also rubs against the inner wall of the airflow channel, resulting in significant noise and impacting the user experience.

[0004] For example, patent CN211975528U discloses a garden fan, including a housing assembly, a noise reduction hole area, and a noise reduction component. The noise reduction hole area is formed by multiple noise reduction holes arranged in a ring along the airflow channel. The noise reduction holes are opened through the side wall of the duct. The noise reduction hole area is spaced at a preset distance from the blade area of ​​the duct that faces the fan blades. The noise reduction component at least partially covers the outer wall of the noise reduction hole area, thereby achieving a noise reduction effect.

[0005] However, in the aforementioned patent, the silencing component is fixed to the outer wall of the culvert, which affects the overall diameter of the culvert and leads to an excessively large overall volume of the culvert. In addition, since the silencing holes penetrate through the side wall of the culvert, the silencing component needs to seal all the silencing holes to prevent the airflow inside the culvert from leaking to the outside of the culvert. Therefore, the structure of the silencing component is relatively complex and the installation is relatively cumbersome. Furthermore, after long-term use, airflow leakage is also prone to occur, which in turn affects the blowing efficiency of the garden fan. Utility Model Content

[0006] The purpose of this invention is to solve the problem that the structure of the noise reduction component is relatively complex and the installation is relatively cumbersome. To this end, a noise-reducing garden fan is provided, which can simplify the structure of the airflow channel while having a noise reduction effect.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] A noise-reducing garden fan includes a casing, an airflow channel connected to the front end of the casing, a fan disposed within the airflow channel for generating airflow, and a drive motor disposed within the airflow channel or the casing for driving the fan. The inner wall of the airflow channel is provided with an annularly distributed silencing zone, and the orthographic projection of the fan blades on the inner wall of the airflow channel is located within the silencing zone. The silencing zone is provided with multiple silencing slots.

[0009] The beneficial effects of using this utility model are:

[0010] The airflow channel described in this invention has a noise-absorbing area on its inner wall, which is distributed in a ring on the outer periphery of the blades. The noise-absorbing area contains multiple noise-absorbing slots. When the fan blades rotate and generate airflow, noise is also generated. This noise propagates in the airflow channel in the form of sound waves, and some of the noise passes through the airflow channel to the outside of the casing. When the sound waves enter the noise-absorbing slots, some of the sound wave energy is absorbed and dispersed by the slot walls. The concave structure of the noise-absorbing slots increases the contact area between the sound waves and the slot walls, thereby improving the efficiency of sound wave absorption. Furthermore, the air molecules within the noise-absorbing slots interact with the sound waves, converting some of the sound wave energy into heat energy, further consuming the sound wave energy and significantly reducing the intensity and frequency of the noise, resulting in better noise reduction. Secondly, since the fan rotates at high speed within the airflow channel to generate stable airflow, and noise is mainly generated by the fan's rotation, placing the noise-absorbing area on the outer periphery of the blades can improve the absorption efficiency of the noise-absorbing slots, thus enhancing the noise reduction effect of the noise-absorbing area.

[0011] Preferably, the silencing groove does not completely penetrate the sidewall of the airflow channel. By adopting the aforementioned technical solution, since the silencing groove does not completely penetrate the sidewall of the airflow channel, the overall structure of the airflow channel remains intact. Airflow within the airflow channel will not leak from the outside of the silencing groove. Therefore, the design of the silencing groove is less likely to affect the blowing effect of the garden fan, and the airflow channel does not require additional silencing components, keeping the overall structure of the airflow channel simple and reducing the assembly difficulty of the airflow channel.

[0012] Preferably, the airflow channel includes a collector, a diffuser and a duct in sequence along the airflow direction, with the fan located inside the collector and the noise reduction zone located on the inner wall of the collector.

[0013] Preferably, the groove of the silencing hole is triangular in shape and is formed by a radial indentation along the airflow channel.

[0014] Preferably, the silencing groove is shaped like a triangular prism with an acute apex facing the end of the collector furthest from the duct. Using the aforementioned technical solution, since the end furthest from the duct is the air inlet, the inner diameter of the air inlet is the largest to allow more airflow into the collector. Demolding from the air inlet is more convenient and simpler during collector manufacturing. The triangular prism structure of the silencing groove, with its apex facing the air inlet, reduces the contact area between the groove and the mold during demolding, thereby reducing friction and making the collector easier to remove from the mold, thus lowering the demolding difficulty.

[0015] Preferably, the depth of the silencing groove is H, and 0.3mm≤H≤1mm. By adopting the aforementioned technical solution, the area of ​​the sidewall of the silencing groove can be increased, allowing it to absorb more sound waves and improving its absorption efficiency. This enhances the noise reduction effect, resulting in less noise generated by the garden fan during operation and improving the user experience. However, when H<0.3mm, the groove is shallow, the sidewall area is small, and the amount of sound waves absorbed by the groove wall is reduced, decreasing the noise reduction effect. Conversely, when H>1mm, the groove is too deep, potentially causing the airflow channel wall to become too thin, reducing its strength and making it more susceptible to damage.

[0016] Preferably, the airflow channel includes a collector, a diffuser, and a duct in sequence along the airflow direction. The end of the collector furthest from the diffuser is the air inlet, which is funnel-shaped and has multiple continuous sound-absorbing steps on its inner wall. Using the aforementioned technical solution, during fan rotation, airflow enters the airflow channel through the air inlet. During this process, the airflow undergoes a significant turn at the air inlet, generating considerable noise. When the sound waves encounter the sound-absorbing steps, reflection and refraction occur, altering the direction of sound wave propagation. This helps guide the sound waves in different directions, reducing superposition and amplification in specific directions, thereby reducing the intensity and range of noise. Furthermore, the sound-absorbing steps increase the area of ​​the air inlet, increasing the contact area between the sound waves and the air inlet, thus improving the absorption efficiency of the sound waves and further reducing noise intensity.

[0017] Preferably, the silencing step is arranged circumferentially around the inner wall of the collector. The silencing step has a first wall surface and a second wall surface, wherein the first wall surface is perpendicular to the second wall surface and parallel to the axial direction of the collector, and the second wall surface is parallel to the radial direction of the collector; or, the first wall surface and the second wall surface form an obtuse angle. Using the aforementioned technical solution, the first wall surface and the second wall surface are perpendicular to each other, forming a reflective surface. When sound waves encounter the silencing step, the number of reflections and refractions between the first and second wall surfaces increases, thereby dispersing the sound waves in different directions, reducing the superposition and amplification of sound waves in a specific direction, and thus reducing the intensity and range of noise.

[0018] Preferably, the connection between the first wall and the second wall has a transition surface.

[0019] Preferably, the airflow channel includes a collector, a diffuser and a duct in sequence along the airflow direction. The diffuser is provided with a mounting bracket for fixing the drive motor in the middle. Several guide plates are provided on the outer periphery of the mounting bracket. The guide plates extend toward the inner wall of the diffuser and are fixedly connected to the diffuser. Several noise-reducing serrations are provided on the side of the guide plate away from the collector. The width of the noise-reducing serrations gradually decreases in the airflow direction.

[0020] Preferably, the airflow channel includes a collector, a diffuser, and a duct in sequence along the airflow direction. The end of the duct furthest from the collector is the air outlet. The air outlet has several silencing serrations distributed circumferentially along its edge, with the width of the serrations gradually decreasing in the airflow direction. In the prior art, the air outlet edge of the airflow channel is flush. Because the airflow velocity outside the airflow channel is gentle, when a high-speed airflow is blown out from the air outlet, vortices form between the airflow and the outside air, resulting in significant noise at the air outlet. In this embodiment, the silencing serrations can break the vortices formed at the air outlet into laminar flow, thereby reducing the formation of vortices at the air outlet and achieving the effects of stabilizing airflow and reducing noise.

[0021] Preferably, the end of the silencing sawtooth is an arc surface; or, the end profile of the silencing sawtooth is similar to that of an owl's wing, and the polynomial fitting formula for the end profile of the silencing 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 coefficients in the fitted formula is ±50%.

[0024] Other features and advantages of this utility model will be disclosed in detail in the following specific embodiments and accompanying drawings. Attached Figure Description

[0025] The present invention will be further described below with reference to the accompanying drawings:

[0026] Figure 1 This is a structural schematic diagram of a noise-reducing garden fan according to the present invention;

[0027] Figure 2 This is an exploded view of a noise-reducing garden fan according to this utility model;

[0028] Figure 3 This is a cross-sectional view of a noise-reducing garden fan according to the present invention;

[0029] Figure 4 for Figure 3 A magnified view of part A in the middle;

[0030] Figure 5 This is a schematic diagram of the collector in a noise-reducing garden fan according to the present invention;

[0031] Figure 6 This is a cross-sectional view of the collector in a noise-reducing garden fan according to this utility model;

[0032] Figure 7 for Figure 6 A magnified view of part B in the middle section;

[0033] Figure 8 This is a schematic diagram of the air duct in a noise-reducing garden fan according to the present invention;

[0034] Figure 9 This is a schematic diagram of the air outlet of a noise-reducing garden fan according to the present invention;

[0035] Figure 10 This is a fitting diagram of the end profile of the noise-reducing sawtooth in a noise-reducing garden fan of this utility model.

[0036] Reference numerals: 1. Housing; 2. Airflow channel; 21. Collector; 211. Air inlet; 212. Silencing zone; 213. Silencing slot; 214. Silencing step; 2141. First wall surface; 2142. Second wall surface; 22. Diffuser; 221. Fixing frame; 222. Guide plate; 23. Air duct; 24. Air outlet; 241. Silencing serrations; 25. Drive motor; 26. Fan; 261. Blade; 3. Battery pack. Detailed Implementation

[0037] The technical solutions of the present utility model will be explained and described below with reference to the accompanying drawings. However, the following embodiments are only preferred embodiments of the present utility model and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments in the implementation methods without creative effort are all within the protection scope of the present utility model.

[0038] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "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 accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0039] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0040] like Figures 1 to 10 As shown in the figure, this embodiment demonstrates a noise-reducing garden fan, including a housing 1, an airflow channel 2 connected to the front end of the housing 1, a fan 26 disposed in the airflow channel 2 for generating airflow, and a drive motor 25 disposed in the airflow channel 2 for driving the fan 26. A battery pack 3 for providing power to the drive motor 25 is detachably installed on the housing 1. The airflow 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, it drives the fan 26 to rotate. Air from the outdoor unit of the garden fan enters the housing 1 and enters the airflow channel 2 through the air inlet end 211. Under the action of the fan 26, an airflow with a large flow rate is formed, and finally it is blown out from the air outlet end of the airflow channel 2 to achieve the effect of blowing grass clippings, fallen leaves, etc.

[0041] It is understandable that in other embodiments, the drive motor 25 may also be located outside the airflow channel 2 and inside the housing 1.

[0042] like Figure 3 and Figure 4As shown, in this embodiment, the inner wall of the airflow channel 2 is provided with a ring-shaped silencing zone 212. The orthographic projection of the blades 261 of the fan 26 onto the inner wall of the airflow channel 2 is located within the silencing zone 212, that is, the silencing zone 212 surrounds the outer periphery of the blades 261. The silencing zone 212 is provided with multiple silencing slots 213 that are radially recessed along the airflow channel 2. The silencing slots 213 do not completely penetrate the sidewall of the airflow channel 2. During the operation of the garden fan, the drive motor 25 drives the fan 26 to rotate rapidly, thereby generating airflow. During the rotation of the fan 26, the blades 261 will rub against the airflow, and the airflow will also form vortices at the blades 261, thus generating significant noise. The noise generated by the garden fan is mainly concentrated in the area where the blades 261 are located. After the noise is formed, it will propagate in the airflow channel 2 in the form of sound waves. The silencing zone 212 surrounds the outer periphery of the blades 261, allowing more sound waves to enter the silencing zone 212 during propagation, thereby reducing noise. The utilization rate of the silencing zone 212 is fully improved. When the sound wave enters the silencing slot 213, part of the sound wave energy is absorbed and dispersed by the slot wall of the silencing slot 213. The concave structure of the silencing slot 213 can increase the contact area between the sound wave and the slot wall, thereby improving the efficiency of the silencing slot 213 in absorbing sound waves. In addition, the air molecules in the silencing slot 213 will also interact with the sound wave, converting part of the sound wave energy into heat energy, further consuming the energy of the sound wave, which helps to significantly reduce the intensity and frequency of noise and achieve a better noise reduction effect. Secondly, the silencing slot 213 does not completely penetrate the side wall of the airflow channel 2, so the overall structure of the airflow channel 2 remains intact. The airflow in the airflow channel 2 will not leak from the outside of the silencing slot 213. Therefore, the design of the silencing slot 213 is not likely to affect the blowing effect of the garden fan. Moreover, the airflow channel 2 does not require additional silencing components, keeping the overall structure of the airflow channel 2 simple and reducing the assembly difficulty of the airflow channel 2.

[0043] like Figure 2As shown, in this embodiment, the airflow channel 2 sequentially includes a collector 21, a diffuser 22, and a duct 23 along the airflow direction. The air inlet 211 of the airflow channel 2 is formed at the end of the collector 21 away from the duct 23, and the air outlet 2 is formed at the end of the duct 23 away from the collector 21. The collector 21 is fixed inside the housing 1, and the air inlet 211 of the collector 21 is a flared opening. A pressure ring is also provided inside the housing 1, which wraps around the edge of the air inlet 211 and connects it to the housing 1, thus achieving a fixed connection between the collector 21 and the housing 1. A mounting bracket 221 for fixing the drive motor 25 is provided in the middle of the diffuser 22. The output end of the drive motor 25 extends towards the collector 21. A fan 26 is fixedly connected to the drive motor 25 and is located inside the collector 21. A noise reduction zone 212 is also provided on the inner wall of the collector 21. The 12 are arranged in a ring along the circumferential direction of the inner wall of the collector 21. Several silencing slots 213 are provided within the silencing zone 212. The silencing slots 213 are evenly distributed within the silencing zone 212, and the radial depth of the silencing slots 213 along the collector 21 is H, where 0.3mm≤H≤1mm. This depth increases the area of ​​the sidewalls of the silencing slots 213, allowing them to absorb more sound waves and improving their absorption efficiency. This enhances the noise reduction effect of the silencing slots 213, resulting in less noise generated by the garden fan during operation and improving the user experience. Furthermore, the even distribution of the silencing slots 213 ensures more uniform sound wave absorption in the silencing zone 212, preventing excessively high sound wave intensity at any one point in the collector 21, thus further improving the noise reduction effect of the silencing zone 212.

[0044] When H < 0.3 mm, the depth of the silencing groove 213 is relatively shallow, and the side wall area of ​​the silencing groove 213 is relatively small. After the sound wave enters the silencing groove 213, the groove wall can absorb less sound wave, which will reduce the noise reduction effect of the silencing groove 213. When H > 1 mm, the depth of the silencing groove 213 is too large, which can easily lead to the wall of the airflow channel 2 where the silencing groove 213 is located being too thin, which will reduce the strength of the side wall of the airflow channel 2 and make the airflow channel 2 easily damaged.

[0045] like Figure 4 and Figure 5As shown, in this embodiment, the groove shape of the silencing slot 213 is an isosceles triangle. The silencing slot 213 is radially recessed along the airflow channel 2 to make the shape of the silencing slot 213 a triangular prism. The apex angle of the silencing slot 213 is an acute angle, with an angle range of 15° to 25°. The distance between the apex angle and the bottom edge is h, and 1.5mm ≤ h ≤ 8mm. The apex angle faces the end of the collector 21 away from the duct 23. That is, in the airflow direction, the width of the silencing slot 213 gradually increases. In this embodiment, the collector 21 is manufactured by injection molding. After completion, demolding is required. Since the diameter of the collector 21 at the air inlet 211 is relatively large, demolding from the air inlet 211 is simpler and easier. However, during the demolding process, the groove wall of the silencing hole groove 213 will generate friction with the mold, which will hinder the demolding of the collector 21. In this embodiment, the top corner of the silencing hole groove 213 is oriented towards the air inlet 211, which can reduce the contact area between the silencing hole groove 213 and the mold, thereby reducing the friction between the silencing hole groove 213 and the mold, making it easier for the collector 21 to be ejected from the mold and reducing the demolding difficulty of the collector 21.

[0046] When the angle of the apex is less than 15°, the apex of the silencing groove 213 is too narrow, which reduces the sound waves entering the silencing groove 213 and reduces its noise reduction effect. When the angle of the apex is greater than 25°, the area of ​​the apex of the silencing groove 213 facing the air inlet 211 will increase, which will increase the contact area between the silencing groove 213 and the mold during demolding, increase the friction between the silencing groove 213 and the mold, and make demolding of the collector 21 more difficult.

[0047] It is understandable that in other embodiments, the groove shape of the silencing hole groove 213 may also be circular, rectangular, polygonal, or other shapes.

[0048] To further improve the noise reduction effect of garden fans, such as Figure 6 and Figure 7As shown, in this embodiment, the inner wall of the air inlet 211 is provided with several noise-reducing steps 214. Each noise-reducing step 214 is arranged in a ring along the circumference of the air inlet 211, and the multiple noise-reducing steps 214 are continuously arranged along the axial direction of the air inlet 211. The noise-reducing step 214 includes a first wall surface 2141 and a second wall surface 2142 that are perpendicular to each other. 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. During the rotation of the fan 26, the airflow will enter the airflow channel 2 through the air inlet 211 under the action of the fan 26. Since the air inlet 211 is a flared opening, it can expand... The air intake end absorbs airflow over a wide area. During this process, the airflow changes direction significantly at the air intake end 211, generating considerable noise. When the sound waves generated by this noise encounter the sound-absorbing step 214, they undergo reflection and refraction, thus changing the direction of sound wave propagation. This helps guide the sound waves in different directions, reducing the superposition and amplification of sound waves in a specific direction, thereby reducing the intensity and range of noise. In addition, the sound-absorbing step 214 also increases the area of ​​the air intake end 211, increasing the contact area between the sound waves and the air intake end 211, thereby improving the absorption efficiency of the sound waves at the air intake end 211 and helping to reduce the intensity of noise.

[0049] like Figure 7 As shown, in this embodiment, the length L of the first wall surface 2141 in the axial direction of the collector 21 is 1mm≤L≤5mm; the width D of the second wall surface 2142 in the radial direction of the collector 21 is 0.3mm≤D≤1.5mm. The above structure of the silencing step 214 can improve the absorption efficiency of the silencing step 214 for sound waves while reducing the impact of the silencing step 214 on the airflow. When D<0.3mm, the width of the second wall surface 2142 is small, which will reduce the contact area between the sound waves and the second wall surface 2142, thereby reducing the absorption efficiency of the second wall surface 2142 for sound waves and reducing the noise reduction effect of the silencing step 214. When D>1.5mm, the width of the second wall surface 2142 is too large. When the airflow flows to the second wall surface 2142, the second wall surface 2142 will obstruct the airflow, which will easily lead to the loss of airflow energy and reduce the airflow velocity, thereby affecting the blowing effect of the garden fan.

[0050] It is understandable that in other embodiments, the first wall surface 2141 and the second wall surface 2142 may also be at an obtuse angle, which can reduce the resistance of the silencing step 214 to the airflow entering the collector 21, reduce the energy loss of the airflow, help maintain the airflow speed, and enable the garden fan to have a better blowing effect.

[0051] It is understandable 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 spline curves, thereby increasing the area of ​​the sound-absorbing step 214 and helping to improve the noise reduction effect of the sound-absorbing step 214.

[0052] like Figure 8 As shown, in this embodiment, the diffuser 22 has a mounting bracket 221 in the middle for fixing the drive motor 25. The outer periphery of the mounting bracket 221 has several guide plates 222. The guide plates 222 extend towards the inner wall of the diffuser 22 and are fixedly connected to it. The side of the guide plate 222 away from the collector 21 has several silencing serrations 241. The mounting bracket 221 is positioned in the middle of the diffuser 22 to maintain a uniform gap between the mounting bracket 221 and the diffuser 22, ensuring that the airflow remains stable and uniform after passing through the mounting bracket 221. Additionally, the guide plates 22... 2. It can also guide the airflow, reduce the eddies generated in the diffuser 22, make the airflow more stable, help maintain the airflow speed, and give the garden fan a better blowing effect. At the same time, it can also reduce the noise generated by the airflow in the diffuser 22, which helps to improve the user experience. Secondly, the sound-absorbing sawtooth 241 set at the end of the guide plate 222 can also convert the eddies formed at the end of the guide plate 222 into laminar flow, thereby reducing the formation of eddies at the end of the guide plate 222, thus achieving the effect of stabilizing the airflow and reducing noise.

[0053] like Figure 9 As shown, in this embodiment, the air outlet end of the duct 23 is equipped with an air outlet nozzle 24. The end of the air outlet nozzle 24 away from the duct 23 is provided with several noise-absorbing serrations 241 distributed along the axial direction of the air outlet nozzle 24. The width of the noise-absorbing serrations 241 gradually decreases in the airflow direction, that is, the end of the noise-absorbing serrations 241 forms a sharp point. A gap is formed between two adjacent noise-absorbing serrations 241, and the width of the gap gradually increases in the airflow direction. In the prior art, the air outlet edge of the airflow channel 2 is flush. Since the airflow speed outside the airflow channel 2 is slow, when the high-speed airflow blows out from the air outlet end to the outside, the airflow will form a vortex with the outside air, which will generate a large noise at the air outlet end. In this embodiment, the noise-absorbing serrations 241 can break the vortex formed at the air outlet end into laminar flow, thereby reducing the formation of vortices at the air outlet end, thereby achieving the effect of stabilizing the airflow and reducing noise.

[0054] like Figure 9 and Figure 10 As shown, in this embodiment, the number of silencing serrations 241 at the end of the air outlet 24 is 10 to 30. The end profile of the silencing serrations 241 is similar to that of an owl's wing. The polynomial fitting formula for the end profile of the silencing serrations 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 coefficients in the fitted formula is ±50%.

[0057] It is understandable that the end of the noise-silencing sawtooth 241 in other embodiments may also be an arc surface.

[0058] The above description is merely a specific embodiment of this utility model, but the protection scope of this utility model is not limited thereto. Those skilled in the art should understand that this utility model includes, but is not limited to, the content described in the accompanying drawings and the specific embodiments above. Any modifications that do not depart from the functional and structural principles of this utility model will be included within 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) disposed within the airflow channel (2) for generating airflow, and a drive motor (25) disposed within the airflow channel (2) or the housing (1) for driving the fan (26), characterized in that, The inner wall of the airflow channel (2) is provided with a ring-shaped silencing area (212). The orthographic projection of the blades (261) of the fan (26) on the inner wall of the airflow channel (2) is located within the silencing area (212). The silencing area (212) is provided with multiple silencing holes (213).

2. The noise-reducing garden fan according to claim 1, characterized in that, The silencing groove (213) does not completely penetrate the side wall of the airflow channel (2).

3. The noise-reducing garden fan according to claim 1, characterized in that, The airflow channel (2) includes a collector (21), a diffuser (22) and a duct (23) in sequence along the airflow direction. The fan (26) is located inside the collector (21), and the noise reduction zone (212) is located on the inner wall of the collector (21).

4. A noise-reducing garden fan according to claim 1, characterized in that, The groove of the silencing hole (213) is triangular in shape and is formed by radial indentation along the airflow channel (2).

5. A noise-reducing garden fan according to claim 4, characterized in that, The silencing slot (213) is a triangular prism with an acute apex that faces the end of the collector (21) away from the duct (23).

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

7. A noise-reducing garden fan according to claim 1, characterized in that, The airflow channel (2) includes a collector (21), a diffuser (22) and a duct (23) in sequence along the airflow direction. The end of the collector (21) away from the diffuser (22) is the air inlet (211). The air inlet (211) is horn-shaped, and the inner wall of the air inlet (211) is provided with multiple and continuous sound-absorbing steps (214).

8. A noise-reducing garden fan according to claim 7, characterized in that, The silencing step (214) is arranged circumferentially around the inner wall of the collector (21). The silencing 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, the first wall surface and the second wall surface form an obtuse angle.

9. A noise-reducing garden fan according to claim 8, characterized in that, The connection between the first wall surface (2141) and the second wall surface (2142) has a transition surface.

10. A noise-reducing garden fan according to claim 1, characterized in that, The airflow channel (2) includes a collector (21), a diffuser (22) and a duct (23) in sequence along the airflow direction. The diffuser (22) has a fixing frame (221) for fixing the drive motor (25) in the middle. The outer periphery of the fixing frame (221) is provided with several guide plates (222). The guide plates (222) extend to the inner wall of the diffuser (22) and are fixedly connected to the diffuser (22). The side of the guide plate (222) away from the collector (21) is provided with several noise-reducing serrations (241). The width of the noise-reducing serrations (241) gradually decreases in the airflow direction.

11. A noise-reducing garden fan according to claim 1, characterized in that, The airflow channel (2) includes a collector (21), a diffuser (22) and a duct (23) in sequence along the airflow direction. The end of the duct (23) away from the collector (21) is the air outlet. The air outlet has several silencing serrations (241) distributed circumferentially along the air outlet. The width of the silencing serrations (241) gradually decreases in the airflow direction.

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

Images