Fan and cleaning device

Abstract

The utility model discloses a fan and cleaning equipment relates to fan technical field, and the fan includes the casing, at least two impellers, drive assembly and at least one backflow ware, and the casing is equipped with the first air inlet, cavity and first air outlet that communicate in proper order, at least two impellers are respectively rotatory installation in the cavity, and at least two impellers are arranged in proper order from the direction of first air inlet to first air outlet and the number of blades is increasing in proper order, drive assembly is connected with at least two impellers and is used for driving impeller rotation, and backflow ware is installed in the cavity, and backflow ware is equipped with the flow guide channel, wherein, between two adjacent impellers, be equipped with a backflow ware, and the flow guide channel is used for guiding the airflow between two adjacent impellers. The utility model discloses a fan can reduce the airflow loss, improve operating efficiency, enhance the suction.

Description

Technical Field

[0001] This utility model relates to the field of fan technology, and in particular to a fan and cleaning equipment. Background Technology

[0002] Cleaning equipment such as robotic vacuum cleaners and traditional vacuum cleaners are equipped with fans. When the fans are running, they create negative pressure and generate suction. The cleaning equipment uses this suction to pick up dust, hair, and other foreign objects, thus achieving the purpose of cleaning. The strength of the fan's suction affects the cleaning effect of the equipment.

[0003] In related technologies, to improve the vacuum and suction power of a blower, multiple impellers are used to perform multi-stage compression of the gas, thereby increasing the negative pressure at the blower's inlet to enhance suction. However, due to unreasonable impeller design, as the gas is compressed sequentially by multiple impellers, turbulence occurs when the compressed gas passes through each subsequent impeller, and the turbulence becomes more pronounced at each later impeller stage. This results in significant airflow loss, low operating efficiency, and negatively impacts the cleaning effect of the cleaning equipment. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes a fan that can reduce airflow loss, improve operating efficiency, and enhance suction.

[0005] This utility model also provides a cleaning device having the above-mentioned fan.

[0006] A fan according to a first aspect of the present invention includes a housing, having a first air inlet, a cavity, and a first air outlet connected in sequence; at least two impellers, each rotatably mounted in the cavity, the at least two impellers being arranged sequentially from the first air inlet to the first air outlet with the number of blades increasing sequentially; a drive assembly connected to the at least two impellers and used to drive the impellers to rotate; and at least one return valve installed in the cavity, the return valve having a guide channel; wherein, a return valve is provided between two adjacent impellers, the guide channel being used to guide the airflow between the two adjacent impellers.

[0007] The fan according to the first aspect of the present invention has at least the following beneficial effects: By driving at least two impellers to rotate through a drive assembly, gas can be drawn into the cavity from the first air inlet. The at least two impellers sequentially compress the gas, achieving a gradual increase in gas pressure. The compressed gas is discharged from the first air outlet, thereby enabling the fan to obtain higher suction power. Since the number of blades on the at least two impellers increases sequentially from the first air inlet to the first air outlet, the size of the flow channel between adjacent blades decreases sequentially between the at least two impellers. Therefore, as the gas pressure increases, the space of the flow channel through the impeller decreases, thereby reducing the risk of airflow turbulence caused by the diffusion of high-pressure gas due to excessive space. This effectively reduces turbulence, thereby reducing airflow loss, improving the fan's operating efficiency, and contributing to increased suction power and improved cleaning effect of the cleaning equipment.

[0008] According to some embodiments of this utility model, the number of blades of any one of the impellers is N, which satisfies: 7≤N≤13.

[0009] According to some embodiments of the present invention, the reflux device includes a plurality of guide vanes, which are arranged at intervals along the direction surrounding the central axis of the reflux device. A flow channel is formed between two adjacent guide vanes, and the number of guide vanes in any reflux device is coprime to the number of blades in any impeller.

[0010] According to some embodiments of the present invention, the housing includes a first inner wall, which is located radially outside the impeller and arranged around the outer periphery of the impeller. The maximum inner diameter of the space surrounded by the first inner wall is D1, and the maximum outer diameter of the impeller is D2, satisfying: 1.25≤D1 / D2≤1.43.

[0011] According to some embodiments of this utility model, the maximum outer diameter of the reflux device is D3, and the maximum outer diameter of the impeller is D2, satisfying: 1.05≤D3 / D2≤1.2.

[0012] According to some embodiments of this utility model, the maximum outer diameter of the impeller is D2, and the minimum axial spacing between any two adjacent impellers is L, satisfying: 1.27≤D2 / L≤1.87.

[0013] According to some embodiments of this utility model, the impeller is provided with a second air inlet and a plurality of second air outlets. The second air inlet is located at one axial end of the impeller, and the plurality of second air outlets are located on the outer peripheral wall of the impeller and arranged at intervals along the circumference of the impeller. In any two adjacent impellers, the impeller closer to the first air inlet is the upper stage impeller, and the impeller closer to the first air outlet is the lower stage impeller. The minimum inner diameter of the second air inlet of the upper stage impeller is D4, and the minimum inner diameter of the second air inlet of the lower stage impeller is D5, satisfying: 0.8≤D5 / D4<1.

[0014] According to some embodiments of this utility model, the minimum axial width of the second air outlet of the upper stage impeller is W1, and the minimum axial width of the second air outlet of the lower stage impeller is W2, satisfying: 0.6≤W2 / W1≤0.9.

[0015] According to some embodiments of the present invention, the fan further includes a diffuser, which is installed in the cavity. The diffuser is located on the side of the impeller facing the first air outlet, near the first air outlet. The diffuser is provided with a diffusion channel for diffusering the airflow.

[0016] The cleaning device according to a second aspect of the present invention includes the fan of the first aspect of the present invention.

[0017] The cleaning device according to the second aspect of this utility model has at least the following beneficial effects: Because the cleaning device uses the aforementioned fan, which drives at least two impellers to rotate via a drive assembly, gas is drawn into the cavity from the first air inlet. The at least two impellers sequentially compress the gas, achieving a gradual increase in gas pressure. The compressed gas is discharged from the first air outlet, thereby enabling the fan to obtain higher suction power. Since the number of blades on the at least two impellers increases sequentially from the first air inlet to the first air outlet, the size of the flow channel between adjacent blades decreases sequentially between the at least two impellers. Therefore, as the gas pressure increases, the space of the flow channel through the impeller decreases, thereby reducing the risk of airflow turbulence caused by the diffusion of high-pressure gas due to excessive space. This effectively reduces turbulence, thereby reducing airflow loss, improving the fan's operating efficiency, and ultimately enhancing the fan's suction power and the cleaning effect of the cleaning device.

[0018] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic diagram of the fan structure in an embodiment of this utility model; Figure 2 This is a front sectional view of the fan in an embodiment of this utility model; Figure 3 This is a schematic diagram of the impeller structure in an embodiment of this utility model; Figure 4 This is a schematic diagram of the reflux device in an embodiment of this utility model; Figure 5 This is a schematic diagram of the diffuser in an embodiment of this utility model.

[0020] Figure label: Housing 100; First air inlet 110; Cavity 120; First inner wall 121; Second inner wall 122; First air outlet 130; Impeller 200; Blades 210; Flow channel 220; Second air inlet 230; Second air outlet 240; Drive assembly 300; stator 310; rotor 320; shaft 330; Reflux device 400; Flow guide plate 410; Flow guide channel 420; Diffuser 500; Diffuser channel 510. Detailed Implementation

[0021] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0022] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional 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.

[0023] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" or "second" is used in the description, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.

[0024] In the description of this utility model, unless otherwise explicitly defined, terms such as setting, installing, connecting, assembling, and cooperating should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this utility model in conjunction with the specific content of the technical solution.

[0025] Cleaning equipment such as robotic vacuum cleaners and traditional vacuum cleaners are equipped with fans. When the fans are running, they create negative pressure and generate suction. The cleaning equipment uses this suction to pick up dust, hair, and other foreign objects, thus achieving the purpose of cleaning. The strength of the fan's suction affects the cleaning effect of the equipment.

[0026] In related technologies, to improve the vacuum and suction power of a blower, multiple impellers are used to compress the gas in stages, thereby increasing the negative pressure at the blower's inlet and thus enhancing suction. However, as the gas is compressed sequentially by multiple impellers, the high-pressure gas diffuses through the flow channel of the next impeller due to the large space in the flow channel, causing airflow turbulence, significant airflow loss, reduced blower operating efficiency, decreased suction power, and ultimately affecting the cleaning effect of the cleaning equipment.

[0027] Therefore, referring to Figures 1 to 5 As shown, the first aspect of this utility model provides a fan that can be applied to cleaning equipment such as sweeping robots and vacuum cleaners. The cleaning equipment uses the suction generated by the fan to pick up foreign objects such as dust and hair to achieve the purpose of cleaning. Reference Figure 1 and Figure 2 As shown, it can be understood that the fan includes a housing 100, at least two impellers 200, a drive assembly 300, and at least one return valve 400. The housing 100 is generally cylindrical in shape and has a central axis. The housing 100 is provided with a first air inlet 110, a cavity 120, and a first air outlet 130 connected in sequence. The first air inlet 110 is located at one end of the cavity 120 along the central axis of the housing 100, and the first air outlet 130 is located at the other end of the cavity 120 along the central axis of the housing 100.

[0028] Referring to Figure 2, in some embodiments, it is understood that there are two impellers 200 and one reflux device 400. Specifically, the two impellers 200 are rotatably mounted within the cavity 120 of the housing 100, with their rotation axes arranged along the central axis of the housing 100. The two impellers 200 are arranged sequentially and at intervals along the central axis of the housing 100, i.e., from the first air inlet 110 to the first air outlet 130. The reflux device 400 is fixedly mounted within the cavity 120 of the housing 100 and positioned between the two impellers 200, with its central axis arranged along the central axis of the housing 100.

[0029] Reference Figure 1and Figure 2 As shown, the drive assembly 300 includes a stator 310, a rotor 320, and a shaft 330. The stator 310 is wound around the outer periphery of the rotor 320, and the shaft 330 is fixedly connected to the rotor 320. The stator 310 and the rotor 320 are located on one side of the back cavity 120 of the first air outlet 130. The shaft 330 is arranged along the central axis of the housing 100, and a portion of the shaft 330 extends into the cavity 120 and is fixedly connected to the two impellers 200. Thus, when the rotor 320 rotates, it drives the two impellers 200 to rotate, thereby realizing the rotation of the two impellers 200 through the drive assembly 300.

[0030] Reference Figure 2 and Figure 3 As shown, it can be understood that the impeller 200 is configured as a centrifugal impeller, meaning that the impeller 200 has axial air intake and radial air outlet. Specifically, the impeller 200 is provided with a second air inlet 230 and multiple second air outlets 240. The second air inlet 230 is located at one axial end of the impeller 200, and the multiple second air outlets 240 are located on the outer peripheral wall of the impeller 200 and are arranged at equal intervals along the axial direction of the impeller 200. It is easy to understand that the impeller 200 includes multiple blades 210, which are arranged at equal intervals along the circumference of the impeller 200. A flow passage 220 is defined between two adjacent blades 210, and the end of the flow passage 220 facing away from the rotation axis of the impeller 200 opens to become the second air outlet 240. The second air inlets 230 of both impellers 200 are located at the end of the impeller 200 facing the first air inlet 110.

[0031] Reference Figure 2 and Figure 4 As shown, the return flow device 400 is configured for radial air intake and axial air exhaust. Specifically, the return flow device 400 includes multiple guide vanes 410, which are arranged at equal intervals along the circumference of the return flow device 400. A guide channel 420 is defined between two adjacent guide vanes 410. The end of the guide channel 420 facing away from the central axis of the return flow device 400 is the air inlet of the return flow device 400. The air outlet of the return flow device 400 is located at one end of the return flow device 400 along the central axis, and the air outlet of the return flow device 400 is located at the end of the return flow device 400 facing the first air outlet 130. The guide channel 420 is used to guide the airflow between two adjacent impellers 200.

[0032] Reference Figure 2As shown, it can be understood that the cavity wall of the chamber 120 is spaced apart from the outer peripheral wall of the impeller 200 and the outer peripheral wall of the return valve 400. Therefore, when the drive assembly 300 drives the two impellers 200 to rotate, the gas outside the housing 100 enters the cavity 120 from the first air inlet 110, and flows sequentially through the flow channel 220 of one impeller 200, the space between the cavity wall of the chamber 120 and the outer peripheral wall of the impeller 200, the outer peripheral wall of the return valve 400, the guide channel 420 of the return valve 400, and the flow channel 220 of the other impeller 200, and is discharged from the first air outlet 130. When the gas flows through the impeller 200, the gas enters from the second air inlet 230, flows through the flow channel 220 and is discharged from the second air outlet 240. The high-speed rotating impeller 200 is used to compress the gas, thereby increasing the gas pressure.

[0033] Reference Figure 2 As shown, it can be understood that gas discharged radially from one impeller 200 flows axially to another impeller 200 through the guide channel 420 of the return flow 400. The guide channel 420 precisely guides the airflow between two adjacent impellers 200, which can reduce the risk of airflow turbulence and effectively reduce airflow loss.

[0034] Reference Figure 2 As shown, it can be understood that the two impellers 200 sequentially compress the gas, progressively increasing the gas pressure and thus increasing the pressure difference between the first outlet 130 and the first inlet 110, enabling the fan to achieve higher suction power. Compared to a single impeller 200 solution, using at least two impellers 200, while achieving the same suction power, can reduce the impeller speed, thereby helping to reduce noise. Simultaneously, the lower impeller speed reduces mechanical losses.

[0035] Reference Figure 2 As shown, it can be understood that the number of blades in the two impellers 200 increases sequentially from the first air inlet 110 to the first air outlet 130. That is, in two adjacent impellers 200, the impeller 200 closer to the first air outlet 130 has a greater number of blades than the impeller 200 closer to the first air inlet 110. It is easy to understand that, assuming the outer diameter and axial height of the impellers 200 remain constant, the more blades there are, the smaller the space of a single flow passage 220 in the impeller 200. Therefore, the size of the flow passage 220 in the two impellers 200 decreases sequentially from the first air inlet 110 to the first air outlet 130; that is, in two adjacent impellers 200, the impeller 200 closer to the first air outlet 130 has a smaller space of a single flow passage 220 than the impeller 200 closer to the first air inlet 110.

[0036] Therefore, during the operation of the fan, the gas flows through the cavity 120 and is compressed sequentially by the two impellers 200, gradually increasing the gas pressure. As the gas pressure increases, the space of the flow channel 220 through which the gas flows decreases, thereby reducing the risk of airflow turbulence caused by the diffusion of high-pressure gas due to excessive space. This effectively reduces turbulence, thereby reducing airflow loss, effectively improving the operating efficiency of the fan, and also helping to increase the suction power of the fan, thus achieving the goal of improving the cleaning effect of the cleaning equipment.

[0037] In other embodiments, it is understood that the number of impellers 200 is not limited to two, and the number of return valves 400 is not limited to one. For example, the number of impellers 200 can also be three, with the three impellers 200 fixedly connected to the rotating shaft 330 and arranged sequentially at intervals from the first air inlet 110 to the first air outlet 130, and the number of return valves 400 is two, with one return valve 400 provided between every two adjacent impellers 200; or, the number of impellers 200 can also be four, with the four impellers 200 fixedly connected to the rotating shaft 330 and arranged sequentially at intervals from the first air inlet 110 to the first air outlet 130, and the number of return valves 400 is three, with one return valve 400 provided between every two adjacent impellers 200, etc. Within the output capacity range of the drive assembly 300, as the number of impellers 200 increases, the gas pressure can be further increased, thereby further improving the suction power of the fan.

[0038] In other embodiments, it is understood that, similarly, when the number of return valves 400 is at least two, the number of guide vanes 410 of the at least two return valves 400 increases from the first air inlet 110 to the first air outlet 130, which can also reduce turbulence, reduce airflow loss, and effectively improve the operating efficiency and suction of the fan, which will not be elaborated here.

[0039] Reference Figure 2 and Figure 5As shown, the fan also includes a diffuser 500, which is installed within the cavity 120 and located near the first air outlet 130. The central axis of the diffuser 500 is arranged along the central axis of the housing 100. Specifically, the diffuser 500 is located on the side of the impeller 200 facing the first air outlet 130, near the first air outlet 130. The diffuser 500 is configured for axial air intake and axial air exhaust. The diffuser 500 is provided with multiple diffusion channels 510, which are located on the outer periphery of the diffuser 500 and arranged at equal intervals along the circumference of the diffuser 500. The end of the diffusion channel 510 facing the impeller 200 is the air inlet of the diffuser 500, and the end of the diffusion channel 510 facing the first air outlet 130 is the air outlet of the diffuser 500. The diffuser channel 510 is used to guide the gas discharged radially from the impeller 200 to the first air outlet 130 and to diffuse the airflow. Specifically, the cross-sectional area of ​​the diffuser channel 510 increases from the first air inlet 110 to the first air outlet 130. When the high-pressure gas passes through the diffuser channel 510, it slows down the airflow. This deceleration converts the kinetic energy of the gas into pressure energy, thereby further increasing the gas pressure and further increasing the pressure difference between the first air outlet 130 and the first air inlet 110, so that the fan can obtain higher suction.

[0040] In other embodiments, it is understood that the number of diffusers 500 is not limited to one, but may be two or more, with multiple diffusers 500 arranged sequentially along the central axis of the housing 100 to further increase the gas pressure.

[0041] Reference Figure 3 As shown, it can be understood that the number of blades in any impeller 200 is defined as N, and the number of blades N in impeller 200 satisfies: 7 ≤ N ≤ 13. For example, the number of blades in impeller 200 can be 7, 8, 10, 12, or 13, etc., but it is necessary to ensure that the number of blades in multiple impellers 200 increases from the first air inlet 110 to the first air outlet 130. It is easy to understand that if the number of blades in impeller 200 is too small, the impeller 200 has poor gas compression and pressurization capabilities, which will lead to a decrease in the suction power of the fan; if the number of blades in impeller 200 is too large, the space of the flow channel 220 of impeller 200 is small, the airflow resistance is large, the airflow loss is large, which will also affect the suction power of the fan. Therefore, by reasonably setting the number of blades in impeller 200, the suction power of the fan can be effectively improved.

[0042] Understandably, when gas flows through the flow channel 220 of the impeller 200, noise is generated due to friction between the gas and the multiple blades 210 of the impeller 200. Similarly, when gas flows through the guide channel 420 of the return flow device 400, noise is generated due to friction between the gas and the multiple guide vanes 410 of the return flow device 400. When these two types of noise have the same frequency, resonance will occur, resulting in even louder noise.

[0043] Therefore, it is understandable that the number of guide vanes 410 of any return valve 400 and the number of blades of any impeller 200 are coprime numbers. This allows the frequencies of the noise generated by the friction between the return valve 400 and the impeller 200 and the gas to be staggered, avoiding greater noise due to resonance, thereby effectively reducing the operating noise of the fan.

[0044] Reference Figure 2 As shown, it can be understood that the cavity wall of the cavity 120 is spaced apart from the outer peripheral wall of the impeller 200 and the outer peripheral wall of the return valve 400. Specifically, the cavity wall of the cavity 120 includes a first inner wall 121 and a second inner wall 122. The first inner wall 121 is located radially outside the impeller 200 and is arranged around the outer periphery of the impeller 200. The first inner wall 121 and the outer peripheral wall of the impeller 200 are spaced apart radially from each other. The second inner wall 122 is located radially outside the return valve 400 (the return valve 400 located on the side of the impeller 200 facing the first air outlet 130) and is arranged around the outer periphery of the return valve 400. The second inner wall 122 and the outer peripheral wall of the return valve 400 are spaced apart. The two ends of the second inner wall 122 and the first inner wall 121 are connected opposite each other in the direction of the central axis of the housing 100. It is easy to understand that, in a cross-section perpendicular to the central axis of the housing 100, both the first inner wall 121 and the second inner wall 122 have circular cross-sections. Furthermore, from the first air inlet 110 to the first air outlet 130, the inner diameter of the space surrounded by the first inner wall 121 increases, while the inner diameter of the space surrounded by the second inner wall 122 decreases. Specifically, in a cross-section passing through the central axis of the housing 100, both the cross-sections of the first inner wall 121 and the second inner wall 122 are arc-shaped. Therefore, the gas discharged from the impeller 200 can be guided to the return flow device 400 through the first inner wall 121 and the second inner wall 122, reducing airflow resistance and minimizing airflow loss.

[0045] Reference Figure 2 As shown, it can be understood that the maximum inner diameter of the space surrounded by the first inner wall 121 is defined as D1, which is the diameter of the largest circle intercepted by a section perpendicular to the central axis of the shell 100 on the first inner wall 121. It is easy to understand that if the section of the first inner wall 121 perpendicular to the central axis of the shell 100 is not circular, then D1 is the diameter of the largest circumscribed circle intercepted.

[0046] Reference Figure 2 As shown, it can be understood that the maximum outer diameter of impeller 200 is defined as D2. Generally speaking, the outer contour of impeller 200 is circular, then D2 is the outer diameter at any point of impeller 200. It is easy to understand that if the outer contour of impeller 200 is not circular, then D2 is the diameter of the circumcircle of the outer contour of impeller 200.

[0047] Reference Figure 2 As shown, it can be understood that the maximum inner diameter D1 of the space surrounded by the first inner wall 121 and the maximum outer diameter D2 of the impeller 200 satisfy: 1.25 ≤ D1 / D2 ≤ 1.43. The ratio between the maximum inner diameter D1 of the space surrounded by the first inner wall 121 and the maximum outer diameter D2 of the impeller 200 reflects the relative size of the space between the first inner wall 121 and the outer peripheral wall of the impeller 200 relative to the space surrounded by the first inner wall 121. If D1 / D2 < 1.25, the difference between the maximum inner diameter D1 of the space surrounded by the first inner wall 121 and the maximum outer diameter D2 of the impeller 200 is small. The space between the first inner wall 121 and the outer peripheral wall of the impeller 200 is too small, resulting in high airflow resistance and significant airflow loss when gas flows through this space. If D1 / D2 > 1.43, the difference between the maximum inner diameter D1 of the space surrounded by the first inner wall 121 and the maximum outer diameter D2 of the impeller 200 is large. The space between the first inner wall 121 and the outer peripheral wall of the impeller 200 is too large, causing diffusion when high-pressure gas flows through this space, resulting in airflow turbulence and also significant airflow loss. Therefore, ensuring that 1.25 ≤ D1 / D2 ≤ 1.43, for example, values ​​of D1 / D2 such as 1.25, 1.32, 1.38, or 1.43, can effectively reduce airflow loss and improve the operating efficiency and suction power of the fan.

[0048] Reference Figure 2 As shown, it can be understood that the maximum outer diameter of the reflux 400 is defined as D3. Generally speaking, the outer contour of the reflux 400 is circular, then D3 is the outer diameter at any point of the reflux 400. It is easy to understand that if the outer contour of the reflux 400 is not circular, then D3 is the diameter of the circumcircle of the outer contour of the reflux 400.

[0049] Reference Figure 2As shown, it can be understood that the maximum outer diameter D3 of the return valve 400 and the maximum outer diameter D2 of the impeller 200 satisfy the condition: 1.05 ≤ D3 / D2 ≤ 1.2. Typically, the impeller 200 is located on the side of the return valve 400 closest to the first air inlet 110. Given a fixed inner diameter of the housing 100 and a fixed maximum outer diameter of the impeller 200, the ratio of the maximum outer diameter D3 of the return valve 400 to the maximum outer diameter D2 of the impeller 200 reflects the size of the maximum outer diameter of the return valve 400. If D3 / D2 < 1.05, the maximum outer diameter of the return valve 400 is too small, resulting in a reduced air inlet area and high airflow resistance; if D3 / D2 > 1.2, the maximum outer diameter of the return valve 400 is too large, reducing the space between the second inner wall 122 and the outer peripheral wall of the return valve 400, which also leads to high airflow resistance. Therefore, ensuring that 1.05 ≤ D3 / D2 ≤ 1.2, for example, that the value of D3 / D2 is 1.05, 1.09, 1.15 or 1.2, can effectively reduce airflow loss and improve the operating efficiency and suction of the fan.

[0050] Reference Figure 2 As shown, it can be understood that the minimum axial spacing between any two adjacent impellers 200 is defined as L. Generally, the minimum axial spacing between any two adjacent impellers 200 is equal, and L can be understood as the minimum distance between two walls of adjacent impellers 200 arranged opposite each other along the axial direction. Since a return valve 400 is installed between two adjacent impellers 200, the minimum axial spacing L between the two adjacent impellers 200 reflects the size of the space used to install the return valve 400, and further reflects the corner size of the second inner wall 122 of the arc-shaped structure.

[0051] Reference Figure 2 As shown, it can be understood that the maximum outer diameter D2 of impeller 200 and the minimum axial distance L between any two adjacent impellers 200 satisfy: 1.27 ≤ D2 / L ≤ 1.87. Given a fixed maximum outer diameter D2 of impeller 200, if D2 / L < 1.27, the minimum axial distance between two adjacent impellers 200 is too large, resulting in an excessively large axial dimension of the fan, increasing its volume and hindering installation. If D2 / L > 1.87, while the space between two adjacent impellers 200 meets the requirements for installing the return valve 400, the minimum axial distance between two adjacent impellers 200 is too small. This results in a large corner of the arc-shaped second inner wall 122, leading to high airflow resistance and significant airflow loss when gas flows through the space between the second inner wall 122 and the outer peripheral wall of the return valve 400. Therefore, ensuring that 1.27 ≤ D² / L ≤ 1.87, for example, D² / L values ​​of 1.27, 1.38, 1.59, or 1.87, can effectively reduce airflow loss, improve the operating efficiency and suction of the fan, optimize the axial dimensions of the fan, reduce its volume, and facilitate installation.

[0052] Reference Figure 2 As shown, it can be understood that, in any two adjacent impellers 200, the impeller 200 closer to the first air inlet 110 is defined as the upper-stage impeller, and the impeller 200 closer to the first air outlet 130 is defined as the lower-stage impeller. The minimum inner diameter of the second air inlet 230 of the upper-stage impeller is defined as D4, and the minimum inner diameter of the second air inlet 230 of the lower-stage impeller is defined as D5. Generally, the outline of the second air inlet 230 in the cross-section perpendicular to the impeller 200 axis is circular, and the inner diameter at any point of the second air inlet 230 is the minimum inner diameter. It is easy to understand that if the outline of the second air inlet 230 in the cross-section perpendicular to the impeller 200 axis is not circular, the minimum inner diameter of the second air inlet 230 is the diameter of the minimum inscribed circle of the second air inlet 230.

[0053] Reference Figure 2 As shown, it can be understood that the minimum inner diameter D4 of the second air inlet 230 of the upper stage impeller and the minimum inner diameter D5 of the second air inlet 230 of the lower stage impeller satisfy: 0.8 ≤ D5 / D4 < 1. That is, the minimum inner diameter of the second air inlets 230 of multiple impellers 200 decreases from the first air inlet 110 to the first air outlet 130. Therefore, as the gas pressure gradually increases, the minimum inner diameter of the second air inlet 230 through which the gas flows decreases, thereby reducing the risk of airflow turbulence caused by the diffusion of high-pressure gas due to excessive space, effectively reducing turbulence, and thus reducing airflow loss, effectively improving the operating efficiency and suction of the fan. At the same time, ensuring D5 / D4 ≥ 0.8 avoids the disadvantage of excessively small minimum inner diameter of the second air inlet 230 of the impeller 200 closest to the first air inlet 110, which would lead to high airflow resistance, thereby reducing airflow loss. Therefore, making 0.8≤D5 / D4<1, for example, D5 / D4 values ​​of 0.8, 0.86, 0.9 or 0.98, can effectively reduce airflow loss and improve the operating efficiency and suction of the fan.

[0054] Reference Figure 2As shown, it can be understood that the minimum axial width of the second outlet 240 of the upper-stage impeller is defined as W1, and the minimum axial width of the second outlet 240 of the next stage is defined as W2, satisfying 0.6≤W2 / W1≤0.9. Generally, the axial width of the second outlet 240 is equal everywhere, and the axial width at any point of the second outlet 240 is the minimum width. It is easy to understand that if the axial width of the second outlet 240 is not equal everywhere, the minimum axial width shall prevail. Similarly, that is, the minimum width of the second outlet 240 of multiple impellers 200 decreases from the first inlet 110 to the first outlet 130. Therefore, as the gas pressure gradually increases, the minimum axial width of the second outlet 240 through which the gas flows decreases, thereby reducing the risk of airflow turbulence caused by the diffusion of high-pressure gas due to excessive space, effectively reducing turbulence, thus reducing airflow loss, and effectively improving the operating efficiency and suction of the fan. Meanwhile, ensuring W2 / W1 ≥ 0.6 avoids the drawback of excessively small axial minimum width of the second outlet 240 of the impeller 200 closest to the first air inlet 110, which would lead to high airflow resistance and thus reduce airflow loss. Therefore, ensuring 0.6 ≤ W2 / W1 ≤ 0.9, for example, with W2 / W1 values ​​of 0.6, 0.75, 0.81, or 0.9, can effectively reduce airflow loss and improve the fan's operating efficiency and suction power.

[0055] The cleaning device of the second aspect of this utility model includes the fan of the first aspect of this utility model. The cleaning device can be a sweeping robot, a vacuum cleaner, etc. The cleaning device uses the suction generated by the fan to pick up dust, hair and other foreign objects to achieve the purpose of cleaning. Since the cleaning equipment adopts all the technical solutions of the fan in the above embodiments, it has at least all the beneficial effects brought about by the technical solutions in the above embodiments.

[0056] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A fan, characterized in that, include: The housing is provided with a first air inlet, a cavity and a first air outlet connected in sequence; At least two impellers are rotatably installed in the cavity, and the at least two impellers are arranged sequentially from the first air inlet to the first air outlet with the number of blades increasing sequentially. A drive assembly, connected to at least two of the impellers and used to drive the impellers to rotate; At least one reflux device is installed in the cavity, and the reflux device is provided with a flow guiding channel; A return flow device is provided between two adjacent impellers, and the flow guide channel is used to guide the airflow between the two adjacent impellers.

2. The fan according to claim 1, characterized in that: The number of blades in any one of the impellers is N, which satisfies: 7≤N≤13.

3. The fan according to claim 1 or 2, characterized in that: The reflux device includes multiple guide vanes, which are arranged at intervals along the direction surrounding the central axis of the reflux device. A flow channel is formed between two adjacent guide vanes. The number of guide vanes in any reflux device is coprime to the number of blades in any impeller.

4. The fan according to claim 1, characterized in that: The housing includes a first inner wall located radially outside the impeller and arranged around the outer periphery of the impeller. The maximum inner diameter of the space surrounded by the first inner wall is D1, and the maximum outer diameter of the impeller is D2, satisfying: 1.25≤D1 / D2≤1.

43.

5. The fan according to claim 1 or 4, characterized in that: The maximum outer diameter of the reflux condenser is D3, and the maximum outer diameter of the impeller is D2, satisfying: 1.05≤D3 / D2≤1.

2.

6. The fan according to claim 1 or 4, characterized in that: The maximum outer diameter of the impeller is D2, and the minimum axial distance between any two adjacent impellers is L, satisfying: 1.27≤D2 / L≤1.

87.

7. The fan according to claim 1, characterized in that: The impeller is provided with a second air inlet and multiple second air outlets. The second air inlet is located at one axial end of the impeller, and the multiple second air outlets are located on the outer peripheral wall of the impeller and arranged at intervals along the circumference of the impeller. In any two adjacent impellers, the impeller closer to the first air inlet is the upper stage impeller, and the impeller closer to the first air outlet is the lower stage impeller. The minimum inner diameter of the second air inlet of the upper stage impeller is D4, and the minimum inner diameter of the second air inlet of the lower stage impeller is D5, satisfying: 0.8≤D5 / D4<1.

8. The fan according to claim 7, characterized in that: The minimum axial width of the second air outlet of the upper stage impeller is W1, and the minimum axial width of the second air outlet of the lower stage impeller is W2, satisfying: 0.6≤W2 / W1≤0.

9.

9. The fan according to claim 1, characterized in that: The fan also includes a diffuser, which is installed in the cavity. The diffuser is located on the side of the impeller facing the first air outlet, near the first air outlet. The diffuser is provided with a diffusion channel for diffusering the airflow.

10. A cleaning device, characterized in that, Includes the wind turbine as described in any one of claims 1 to 9.

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