A noise-reducing fan assembly and a window cleaning robot using it

Abstract

This utility model discloses a noise-reducing fan assembly and a window cleaning robot using the same. The noise-reducing fan assembly includes a lower housing, an upper housing, and a fan support, a drive device, and fan blades disposed within the air cavity formed by the two. Multiple rectification structures are provided on the fan support, downstream of the airflow from the rotating fan blades. These rectification structures actively regulate and streamline the rotating airflow with a tangential velocity component generated from the fan blades, reducing its rotational intensity at the source and thus suppressing vortex formation. Through this design, not only can the operating noise of the fan assembly be significantly reduced, greatly improving the acoustic quality and user experience of the product; simultaneously, because the rectification structures optimize the internal airflow state and reduce energy loss, they also effectively improve the operating efficiency of the fan assembly, thereby enhancing the adsorption performance or battery life of the window cleaning robot.

Description

[Technical Field]

[0001] This utility model relates to the field of cleaning robot technology, and in particular to a noise-reducing fan assembly and a window cleaning robot using the same. [Background Technology]

[0002] Window cleaning robots are a rapidly developing smart home appliance product in recent years. They typically use a built-in fan assembly to generate negative pressure, allowing them to adhere to vertical surfaces such as glass and move autonomously to perform cleaning tasks. The fan assembly, as the core component enabling its suction function, needs to provide continuous and powerful airflow suction within a compact size.

[0003] However, existing window cleaning robots often generate significant operating noise from their fan components during operation, which has become a common technical problem affecting user experience and hindering product promotion. This noise primarily stems from the complex aerodynamic effects within the fan components. Specifically, when the fan blades rotate at high speed, the exhaust airflow is not a smooth, straight flow but naturally carries a strong rotational component, forming a high-speed, unstable rotating airflow. Within the compact internal space of the window cleaning robot, this rotating airflow directly impacts various internal structural components, such as the inner walls of the air chamber.

[0004] In existing designs, the primary design goal of these internal structural components is usually to achieve mechanical support, positioning, or component housing. Their shapes are often not aerodynamically optimized, and they contain many blunt surfaces and sharp angles. The interaction between rotating airflow and these structures can easily induce severe airflow separation, vortex shedding, and pressure pulsation, thereby radiating harsh high-frequency aerodynamic noise, commonly known as "wind whistling" or "howling," which seriously affects the acoustic quality of the product and the user experience. [Utility Model Content]

[0005] The purpose of this utility model is to provide a noise-reducing fan assembly and a window cleaning robot using it, aiming to solve the technical problems in the prior art, such as the severe eddies and high-frequency aerodynamic noise generated by the high-speed rotating airflow discharged from the fan blades impacting the internal structure, resulting in high overall machine operating noise and poor acoustic quality.

[0006] This utility model is achieved through the following technical solution:

[0007] A noise reduction fan assembly, comprising:

[0008] The lower casing has an air inlet at its bottom;

[0009] The upper housing is connected to the lower housing to form an internal air cavity and has an air outlet channel communicating with the air cavity;

[0010] The fan bracket is installed inside the air cavity;

[0011] The drive unit is mounted on the fan bracket;

[0012] The fan blades, connected to the drive device and located below the fan bracket, are used to draw airflow from the air inlet into the air cavity;

[0013] The fan support is provided with multiple rectification structures for rectifying the rotating airflow with a tangential velocity component generated from the fan blades, so as to reduce the tangential velocity component of the rotating airflow.

[0014] As described above, in the noise reduction fan assembly, the rectification structure consists of multiple integrally formed and circularly arrayed guide ribs, with air holes for airflow between any two adjacent guide ribs.

[0015] As described above, in the noise reduction fan assembly, the lower end of the guide rib has a smooth leading edge for smoothly separating the airflow, and the guide rib gradually narrows upward from the smooth leading edge, and the upper end has a angular trailing edge for stabilizing the airflow separation point.

[0016] In the noise reduction fan assembly described above, the extension direction of the plurality of guide ribs is parallel to the central rotation axis of the fan blades.

[0017] As described above, in the noise reduction fan assembly, multiple quick-release structures are provided between the outer side wall of the fan bracket and the inner side wall of the lower housing to achieve detachable fixing of the two.

[0018] The noise reduction fan assembly described above, wherein the quick-installation structure includes:

[0019] A first engaging portion is disposed on one of the lower housing and the fan bracket; and

[0020] The second engaging part is provided on the other and engages with the first engaging part;

[0021] The first engaging part and the second engaging part can be detachably locked together by an axial insertion action and a subsequent circumferential rotation action.

[0022] In the noise reduction fan assembly described above, the first engaging part is an L-shaped groove, and the second engaging part is a rectangular protrusion that engages with and connects to the L-shaped groove.

[0023] As described above, in the noise reduction fan assembly, the upper and lower edges of the fan bracket are tightly aligned with the inner walls of the upper and lower housings after assembly, so as to form a smooth and continuous transition surface at the connection of the three components in the air cavity.

[0024] As described above, the noise reduction fan assembly has a mating groove on the inner wall of the lower housing for radial and circumferential positioning of the fan bracket, and a mating part at the lower end of the fan bracket that mates with the mating groove. After the upper housing is assembled with the fan bracket, the lower end of the inner wall of the upper housing applies axial pressure to the upper end of the fan bracket so that the mating part abuts against the mating groove.

[0025] A window cleaning robot, including the noise-reducing fan assembly as described above.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] 1. This utility model, by setting a rectification structure downstream of the fan blades, forcibly regulates and sorts the high-speed rotating airflow discharged from the fan blades at its source, actively and effectively reducing the tangential velocity component that generates vortex noise. This design fundamentally solves the problem of high-frequency "whistling" noise generated by the impact of rotating airflow on the internal structure of traditional fans, making the operation of the fan components and even the entire window cleaning robot quieter and softer, greatly improving the acoustic quality of the product and the user experience.

[0028] 2. The rectifying structure of this invention not only reduces noise, but its optimized aerodynamic shape, combined with the smoothly designed inner wall of the air cavity, makes the airflow within the fan assembly smoother, minimizing energy loss. This means that, with the same power consumption, the fan assembly of this invention can generate stronger suction force, improving the adsorption performance of the window cleaning robot; or, while maintaining the same adsorption force, it consumes less power, effectively extending the overall runtime.

[0029] 3. This utility model, through its optimized assembly structure, ensures that core components such as the fan bracket are precisely and securely fixed within the housing assembly. This highly stable structure not only guarantees the precise alignment of the smooth transition surfaces between components but also effectively suppresses vibrations generated by the fan assembly during high-speed operation, thereby improving the long-term reliability of the fan assembly and extending the service life of the entire machine. [Attached Image Description]

[0030] To more clearly illustrate the technical solutions in the embodiments of the utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below.

[0031] Figure 1 This is a schematic diagram of the three-dimensional structure of this embodiment. Figure 1 ;

[0032] Figure 2 This is a schematic diagram of the three-dimensional structure of this embodiment. Figure 2 ;

[0033] Figure 3 This is a schematic diagram of the three-dimensional structure of this embodiment. Figure 3 ;

[0034] Figure 4 This is a top view of this embodiment;

[0035] Figure 5 for Figure 4 Sectional view along line AA;

[0036] Figure 6 for Figure 4 Sectional view along the BB line;

[0037] Figure 7 for Figure 5 A magnified schematic diagram of the change in airflow direction at point C;

[0038] Figure 8 This is a schematic diagram of the exploded structure of this embodiment. Figure 1 ;

[0039] Figure 9 This is a schematic diagram of the exploded structure of this embodiment. Figure 2 ;

[0040] Figure 10 This is a schematic diagram of the assembly of the fan bracket and the lower housing in this embodiment;

[0041] Figure 11 This is a three-dimensional structural diagram of the lower shell in this embodiment;

[0042] Figure 12 This is a three-dimensional structural diagram of the wind turbine support in this embodiment.

Detailed Implementation Methods

[0043] To make the technical problems solved by this application, the technical solutions, and the beneficial effects clearer, this application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0044] Example 1

[0045] This embodiment provides a noise reduction fan assembly. Please refer to the appendix. Figures 1 to 12 The basic structure of the noise reduction fan assembly includes a lower housing 1, an upper housing 2, a fan bracket 4, a drive unit 5, and a fan blade 6.

[0046] Specifically, the lower housing 1 has an air inlet 11 at its bottom center for drawing in air from the outside. The upper housing 2 is connected to the lower housing 1 by snap-fit, screw-fit, or other conventional connection methods in the art, together defining an internal air cavity 3 for accommodating other components and guiding airflow. The upper housing 2 also has one or more air outlet channels 21 for discharging the airflow from the air cavity 3 outward.

[0047] The fan bracket 4, as a key load-bearing and functional component, is fixedly installed inside the air chamber 3. The drive unit 5, such as a brushless or brushed DC motor, is mounted and fixed to the fan bracket 4. The fan blades 6, such as a centrifugal or mixed-flow impeller, are connected to the output shaft of the drive unit 5 and are located below the fan bracket 4. When the drive unit 5 operates, it drives the fan blades 6 to rotate at high speed, thereby generating a strong suction force that draws air in from the air inlet 11, flows through the fan blades 6, and impacts upwards into the air chamber 3.

[0048] The core innovation of this embodiment lies in the integral installation of multiple rectification structures 41 on the fan support 4, downstream of the airflow from the fan blades 6. Due to its high-speed rotation, the airflow discharged from the fan blades 6 possesses not only axial velocity but also a strong tangential velocity component, thus forming a rotating airflow. This rotating airflow is the primary source of vortices and high-frequency aerodynamic noise. The rectification structure 41 in this embodiment does not primarily guide the airflow but actively and forcibly rectifys this rotating airflow. Through interaction with the airflow, it effectively reduces its tangential velocity component, disrupting the conditions for vortex formation at its source, thereby achieving a significant noise reduction effect and making the airflow smoother.

[0049] Furthermore, as a preferred embodiment, the rectifying structure 41 specifically comprises a plurality of annularly arrayed guide ribs 411. These guide ribs 411 are integrally formed on the fan bracket 4, resulting in high structural strength and good production consistency. Between any two adjacent guide ribs 411, air holes 412 are naturally defined for airflow to pass through. After being accelerated by the fan blades 6, the airflow will pass through these air holes 412.

[0050] Furthermore, to maximize the rectification and noise reduction effect, this embodiment features a special aerodynamic design for the cross-sectional profile of the guide rib 411. Please refer to the appendix for details. Figures 5 to 7The guide rib 411 has a streamlined cross-section that is symmetrical along its central axis but has different front and rear profiles along the airflow direction. Specifically, the lower end of the guide rib 411, i.e., the side facing the airflow impact, has a smooth leading edge 4111 for smoothly separating the airflow. When the high-speed airflow impacts this smooth leading edge 4111, it can be smoothly separated to both sides, avoiding the violent pressure pulsation and impact noise caused by the head-on collision of the airflow with the blunt body. Subsequently, the rib of the guide rib 411 gradually narrows upward from the smooth leading edge 4111, and forms a angular trailing edge 4112 at its upper end for stabilizing the airflow separation point. This structure allows the airflow flowing around the rib to form a stable and clear separation point at the angular trailing edge 4112, greatly suppressing the wake vortex formed behind the rib due to the alternating shedding of airflow, thereby further reducing fluid noise. Of course, those skilled in the art will understand that the above-mentioned technical effects of smooth flow separation and wake suppression are not limited to the specific cross-sectional shape mentioned above. Based on the core concept of this application, there are several other feasible cross-sectional profile options. For example, in some alternatives, the cross-section of the guide rib 411 can be designed as a standard ellipse, with its major axis aligned along the axial direction of the airflow, i.e., parallel to the central rotation axis of the fan blade 6. Preferably, a high-eccentricity ellipse with a large ratio between its major and minor axes can be used. This configuration results in the guide rib presenting the narrowest windward face and a smooth flow profile to the main axial airflow, thereby significantly reducing form drag; while its thickness along the minor axis effectively impedes and regulates the lateral rotating airflow. Its perfectly smooth surface minimizes frictional and pressure drag when the airflow contacts the rib. Compared to angular shapes, the elliptical cross-section better maintains the boundary layer adhesion state, delaying the occurrence of airflow separation points, thereby effectively reducing broadband turbulent noise and resulting in a cleaner overall wind noise.

[0051] Furthermore, as a preferred embodiment, the extension direction of the plurality of guide ribs 411 is set to be parallel to the central rotation axis of the fan blade 6. This axially parallel arrangement makes the ribs of each guide rib form a direct obstruction surface for the tangential velocity component of the rotating airflow, which can effectively cut and block the rotating airflow, forcibly changing its motion direction from tangential to axial, thereby achieving a highly efficient rectification effect.

[0052] This arrangement differs fundamentally from the commonly used spiral or inclined guide structures in existing technologies. The latter are designed to follow the rotational trend of the airflow and smoothly change its flow path through an inclined guide surface; while the axial parallel layout of this embodiment aims to actively and forcibly eliminate the rotational component of the airflow through direct obstruction and segmentation, thereby suppressing the generation of vortices at the source.

[0053] Furthermore, as an alternative, the rectifying structure 41 can be a honeycomb rectifier (not shown in the figure). Specifically, the honeycomb rectifier can be an integral, disc-shaped, or annular structure with a large number of axially parallel microchannels with small apertures running through it. The cross-section of these channels can be hexagonal, quadrilateral, or circular. This rectifier is also fixedly positioned downstream of the airflow of the fan blade 6. When the high-speed rotating airflow impacts this structure, it is forcibly divided into hundreds of fine airflows and enters these parallel microchannels. Under the constraint of the channel walls, the rotational kinetic energy of the airflow is rapidly dissipated, and each fine airflow, upon leaving the channel, has been straightened into a straight flow parallel to the channel axis. In this way, effective rectification of the rotating airflow is also achieved, thereby reducing eddy noise. This honeycomb rectifier can be injection molded from polymer materials or stamped and welded from metal sheets.

[0054] Furthermore, as an alternative, the rectifying structure 41 can also be a multi-stage stator guide ring (not shown in the figure). In this design, the rectification of the rotating airflow is accomplished by at least two fixed blade stages arranged sequentially along the airflow path, achieving a finer, more gradual streamlining of the airflow. Specifically, the fan support 4 itself is designed with a multi-stage guide structure. Specifically, the fan support 4, in a cross-section perpendicular to the airflow direction, is constructed with at least two layers of concentric or series-connected fixed guide blades.

[0055] The first-stage guide vanes (not shown in the figure) are located at the lower part of the fan support 4, that is, downstream of the airflow immediately adjacent to the rotating fan blades 6. These first-stage vanes can be set at a specific tilt angle opposite to the direction of airflow rotation. Their main function is to make the first impact and initial deceleration on the high-speed rotating airflow, weakening most of its tangential kinetic energy.

[0056] The second-stage guide vanes (not shown in the figure) are located on the upper part of the fan support 4, directly above the first-stage guide vanes. When the airflow, which has undergone initial rectification but still carries some residual rotation and turbulence, continues to flow upward, it will immediately impact the second-stage guide vanes. The tilt angle, curvature, or number of the second-stage guide vanes can differ from the first stage, for example, by using a smaller tilt angle or a denser arrangement, to perform a second, more refined sorting and reverse deflection of the airflow, thereby further eliminating residual rotational components and ensuring that the airflow is essentially a straight axial flow when it finally leaves the fan support.

[0057] In this embodiment, a preferred assembly scheme is also provided. Multiple quick-connect structures 7 are provided between the outer wall of the fan bracket 4 and the inner wall of the lower housing 1 to achieve quick, reliable, and detachable fixing between the two. This design greatly simplifies the assembly process on the production line and improves production efficiency.

[0058] Specifically, the quick-connect structure 7 includes a first engaging portion 71 disposed on one of the lower housing 1 and the fan bracket 4, and a second engaging portion 72 disposed on the other and cooperating with the first engaging portion 71. During assembly, a simple axial insertion action followed by a slight circumferential rotation action locks the two engaging portions together. Specifically, as an optional preferred embodiment, the first engaging portion 71 can be multiple L-shaped grooves formed on the inner wall of the lower housing 1, while the second engaging portion 72 can be multiple rectangular protrusions correspondingly disposed on the outer wall of the fan bracket 4. Of course, those skilled in the art will understand that the positions of the protrusions and the grooves can be interchanged, and their specific shapes can also be circular, T-shaped, or any other mechanical structure capable of achieving the function of rotational locking after insertion.

[0059] Furthermore, another important innovation of this embodiment lies in the coordinated design of the overall inner wall contour of the air cavity 3. In a preferred embodiment, the upper and lower edges of the fan bracket 4 are tightly aligned with the inner walls of the upper housing 2 and the lower housing 1 after assembly, so that these three independent physical components together form a smooth and continuous transition surface at their connecting seams. The core idea of ​​this design is to treat the inner wall of the air cavity 3 as a whole aerodynamic surface, eliminating steps, gaps, or sharp corners caused by component assembly tolerances in traditional designs, thereby avoiding severe secondary turbulence in the airflow at these small obstacles, and ensuring the achievement of ultimate quietness. It should be added that by optimizing the smoothness of the inner wall of the air cavity 3 and the aerodynamic shape of the rectifying structure 41, the energy loss of the airflow inside the fan assembly is greatly reduced. This means that, under the same power consumption, the window cleaning robot using the noise reduction fan assembly of this embodiment can generate stronger adsorption force, or consume less power while maintaining the same adsorption force, thereby extending the battery life. Meanwhile, the precise and robust assembly structure and vibration suppression also improve the long-term reliability of the wind turbine components and the service life of the entire unit.

[0060] To stably achieve the aforementioned smooth and continuous transition surface, this embodiment also provides a preferred precision positioning and locking structure. Specifically, one or more mating grooves 12 are provided on the inner wall of the lower housing 1 for precise radial and circumferential positioning of the fan bracket 4. Correspondingly, a mating part 42 is provided at the lower end of the fan bracket 4 to mate with the mating groove 12. During assembly, the mating part 42 is embedded in the mating groove 12, thus eliminating the swaying of the fan bracket 4 in the horizontal plane. Based on this, when the upper housing 2 and the lower housing 1 are finally closed and locked, the lower end of the inner wall of the upper housing 2 applies a continuous axial pressure to the upper end of the fan bracket 4, causing the mating part 42 of the fan bracket 4 to abut against the mating groove 12 of the lower housing 1. In this way, through the pressure from above and the support from below, the fan bracket 4 is stably axially locked within the air cavity 3 formed by the upper housing 2 and the lower housing 1.

[0061] As a further optimization, one or more annular reinforcing ribs 43 are integrally formed on the outer wall of the wind turbine support 4. The outer diameter of the annular reinforcing rib 43 is designed to be slightly larger than the inner diameter of the corresponding position of the lower housing 1, so that a stable interference fit can be formed between the two during assembly. This interference fit not only provides additional radial support force for the wind turbine support 4 and enhances the rigidity of the overall structure, but also effectively suppresses the transmission of high-frequency vibrations between components, playing an auxiliary role in vibration reduction and noise reduction.

[0062] Furthermore, as an alternative to the quick-installation structure 7, the quick-installation structure 7 can be an elastic snap-fit ​​structure. Specifically, multiple elastic cantilever hooks (not shown in the figure) can be integrally formed on the outer wall of the fan bracket 4. Correspondingly, slots (not shown in the figure) that mate with the cantilever hooks are formed on the inner wall of the lower housing 1. During assembly, no rotation is required; the fan bracket 4 is simply pressed directly into the lower housing 1 axially. During this process, the inclined surface of the cantilever hook will contact and be compressed against the inner wall of the lower housing 1, producing elastic deformation. When the fan bracket 4 is pressed into place, the hook crosses the edge of the slot and locks into the slot due to its own elastic recovery. The horizontal surface of the hook and the horizontal surface of the slot cooperate with each other to achieve a firm axial fixation. The advantage of this solution is that the assembly action is simple and extremely fast, and it is particularly suitable for applications using engineering plastics with good toughness such as ABS and PC. In contrast, the presence of hooks or slots to achieve the snap-fit ​​function may introduce some local discontinuities in the smoothness of the inner wall of the air cavity, and its contribution to the overall airflow smoothness is slightly different from that of the aforementioned plug-in rotation locking structure.

[0063] Furthermore, as another alternative to the quick-installation structure 7, the quick-installation structure 7 can also be an axially sliding locking structure. Specifically, one or more axially extending guide rails (not shown in the figure), such as T-shaped guide rails or dovetail grooves, can be provided on the inner wall of the lower housing 1. Correspondingly, a slider (not shown in the figure) or dovetail tenon (not shown in the figure) matching the guide rail is provided on the outer wall of the fan bracket 4. During assembly, the slider of the fan bracket 4 is aligned with the guide rail inlet of the lower housing 1, and then smoothly slid in axially until it reaches the predetermined position. To prevent accidental slippage after assembly, a positioning protrusion (not shown in the figure) can be provided at the end of the guide rail, and a corresponding positioning recess (not shown in the figure) can be provided on the slider. When the slider slides into place, the protrusion and the recess will create a slight engagement, providing clear confirmation of placement and reliable axial locking. The advantage of this solution is high connection strength and the ability to withstand large torques. When designing, it is necessary to consider that the presence of guide rails and sliders may introduce additional seams into the inner wall of the air cavity, which will place higher design and processing requirements on achieving a smooth and continuous transition surface.

[0064] In summary, this embodiment, through the coordinated design of the rectifier structure, the inner wall contour of the air cavity, and the assembly structure of each component, not only achieves a significant noise reduction effect, but also achieves a comprehensive improvement in overall performance.

[0065] Example 2

[0066] This embodiment provides a window cleaning robot. Those skilled in the art will understand that the window cleaning robot may include conventional components such as a body for housing internal components, a motion component for moving on the cleaning surface, a cleaning component for performing cleaning tasks, a control component for processing data and executing instructions, and a power supply component for providing power to the entire machine. Furthermore, in order to adhere to vertical glass surfaces, the window cleaning robot must also include a fan component capable of generating negative pressure. The innovation of the window cleaning robot provided in this embodiment lies in its use of the noise-reducing fan component as described in Embodiment 1.

[0067] This window cleaning robot uses negative pressure generated by its fan assembly to adhere to the glass surface to be cleaned. Thanks to the rectification and noise reduction structure, smooth airflow design, and precise and stable assembly structure described in Example 1, the built-in fan assembly provides strong suction while significantly reducing operating noise compared to existing products. In particular, it eliminates the unpleasant high-frequency whistling sound, resulting in a quieter and gentler overall operation. This greatly improves the user experience in indoor environments and solves the problem of excessive noise in existing window cleaning robots. Furthermore, the energy loss of airflow within the fan assembly is significantly reduced. This means that, with the same power consumption, the window cleaning robot using the noise-reducing fan assembly described in Example 1 can generate stronger suction, or consume less power while maintaining the same suction, thus extending battery life. Simultaneously, the precise and stable assembly structure and vibration suppression also improve the long-term reliability and overall lifespan of the window cleaning robot. In summary, it has significant practical value and a competitive advantage in the market.

[0068] The above are implementation methods provided in conjunction with specific content, and it is not intended that the specific implementation of this application is limited to these descriptions. Any methods or structures that are similar to those of this application, or any technical deductions or substitutions made based on the concept of this application, should be considered within the scope of protection of this application.

Claims

1. A noise reducing fan assembly comprising: include: The lower housing (1) has an air inlet (11) at its bottom. The upper housing (2) is connected to the lower housing (1) to form an internal air cavity (3) and has an air outlet channel (21) communicating with the air cavity (3). A fan bracket (4) is installed inside the air cavity (3); The drive unit (5) is installed on the fan bracket (4); The fan blade (6) is connected to the drive device (5) and located below the fan bracket (4) to draw airflow from the air inlet (11) into the air cavity (3); The fan support (4) is provided with multiple rectification structures (41) for rectifying the rotating airflow with tangential velocity component generated from the fan blade (6) to reduce the tangential velocity component of the rotating airflow.

2. The noise reducing fan assembly of claim 1, wherein, The rectifying structure (41) consists of multiple integrally formed and circularly arrayed guide ribs (411), with air holes (412) for airflow to pass through between any two adjacent guide ribs (411).

3. The noise reducing fan assembly of claim 2, wherein, The lower end of the guide rib (411) has a smooth leading edge (4111) for smooth airflow separation, and the guide rib (411) gradually narrows upward from the smooth leading edge (4111) and has an angular trailing edge (4112) at the upper end for stabilizing the airflow separation point.

4. The noise reducing fan assembly of claim 2, wherein, The extension direction of the plurality of guide ribs (411) is parallel to the central rotation axis of the fan blade (6).

5. The noise reducing fan assembly of claim 1, wherein, Multiple quick-installation structures (7) are provided between the outer side wall of the fan bracket (4) and the inner side wall of the lower housing (1) to achieve detachable fixing of the two.

6. The noise reducing fan assembly of claim 5, wherein, The quick-assembly structure (7) includes: A first engaging portion (71) is provided on one of the lower housing (1) and the fan bracket (4); and The second engaging part (72) is provided on the other and engages with the first engaging part (71); The first engaging part (71) and the second engaging part (72) can be detachably locked together by an axial insertion action and a subsequent circumferential rotation action.

7. The noise reducing fan assembly of claim 6, wherein, The first engaging part (71) is an L-shaped groove, and the second engaging part (72) is a rectangular protrusion that engages with the L-shaped groove.

8. The reduced noise fan assembly of any of claims 1, 4, or 7, wherein, The upper and lower edges of the fan bracket (4) are closely aligned with the inner walls of the upper housing (2) and the lower housing (1) after assembly, so as to form a smooth and continuous transition surface at the connection of the three in the air cavity (3).

9. The noise reducing fan assembly of claim 8, wherein, The inner wall of the lower housing (1) is provided with a docking groove (12) for radial and circumferential positioning of the fan bracket (4). The lower end of the fan bracket (4) is provided with a docking part (42) that is connected to the docking groove (12). After the upper housing (2) is assembled with the fan bracket (4), the lower end of the inner wall of the upper housing (2) applies axial pressure to the upper end of the fan bracket (4) so ​​that the docking part (42) and the docking groove (12) abut against each other.

10. A window cleaning robot, characterized in that, Includes the noise-reducing fan assembly as described in any one of claims 1-9.

Images