Fan and cleaning equipment

Abstract

The invention discloses a fan and cleaning equipment, and relates to the technical field of fans. The draught fan comprises a shell, a first impeller, a second impeller, a driving device and a backflow device, the shell is provided with a first air inlet, a first air passing opening, a first air outlet, a first cavity and a second cavity, the scheme that the first impeller and the second impeller jointly suck air is adopted, primary compression is completed when airflow passes through the first impeller, and secondary compression is completed after the airflow passes through the second impeller; therefore, the fan can obtain higher vacuum degree and larger suction force after two-stage compression. Compared with the prior art, the first impeller and the second impeller do not need to adopt higher rotating speed, noise cannot be obviously increased, mechanical loss can be reduced at low rotating speed, pneumatic loss can be reduced under the guidance of the air inducing channel of the backflow device, and then the working efficiency of the fan is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of fans, and in particular to a fan and cleaning equipment. Background Art

[0002] Cleaning equipment like sweeping robots and vacuum cleaners are equipped with a volute fan for air intake. For example, in vacuum cleaners, the volute fan generates suction to draw in dust, hair, and other debris. The strength of this suction influences the cleaning performance of the vacuum cleaner. Related technologies employ multiple impellers to achieve high vacuum levels and strong suction. However, these impellers often lack proper airflow design, leading to significant airflow losses and low efficiency. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a fan that can reduce airflow loss and improve fan efficiency.

[0004] The present invention also provides a cleaning device having the above-mentioned blower.

[0005] A wind turbine according to an embodiment of the first aspect of the present invention includes:

[0006] The housing is provided with a first air inlet, a first cavity, a first air outlet, a second cavity and a first air outlet which are connected in sequence;

[0007] a first impeller rotatably disposed in the first cavity;

[0008] a second impeller rotatably disposed in the second cavity;

[0009] a driving device, drivingly connected to the first impeller and the second impeller;

[0010] A return flow device is provided in the first cavity and located between the first impeller and the second impeller. The return flow device is formed with an air induction channel, and the air induction channel is used to guide the airflow generated by the first impeller to the second impeller.

[0011] The fan according to the embodiment of the present invention has at least the following beneficial effects:

[0012] By setting the first impeller and the second impeller to rotate under the drive of the driving device, the air flow can be sucked into the first cavity from the first air inlet of the housing, and then passes through the air induction channel of the return device, the first air outlet and the second cavity in sequence, and finally blown out from the first air outlet. Since the first impeller and the second impeller adopt the scheme of jointly sucking air, the air flow completes the first stage of compression when passing through the first impeller, and completes the second stage of compression after passing through the second impeller. Therefore, after the air flow passes through the two-stage compression, the fan will obtain a higher vacuum degree and greater suction force. In addition, the first impeller and the second impeller do not need to use a higher speed, which can ensure that the noise will not increase significantly, and mechanical losses can be reduced at low speeds. At the same time, since the first impeller discharges air in its radial direction, it is easy for the air flow to directly hit the side wall of the first cavity, causing air flow turbulence and large air flow losses. Therefore, the air flow is guided to flow toward the second impeller by setting an air induction channel to reduce aerodynamic losses and thereby improve the working efficiency of the fan.

[0013] According to some embodiments of the present invention, the returner includes an air guide seat and a plurality of guide blades, the plurality of guide blades being connected to the side of the air guide seat facing away from the first impeller, and being arranged at circumferential intervals along the rotation axis of the first impeller, and the air induced channel being formed between adjacent guide blades.

[0014] According to some embodiments of the present invention, a side of the air guide seat facing away from the first impeller protrudes toward the first air outlet.

[0015] According to some embodiments of the present invention, the plurality of guide vanes are connected to the bottom wall of the first cavity, and the bottom wall of the first cavity is inclined toward the first air outlet.

[0016] According to some embodiments of the present invention, a side wall of the first cavity is provided with a guide arc surface, and the guide arc surface is recessed in a direction away from the first impeller and extends to the air inlet end of the air induction channel.

[0017] According to some embodiments of the present invention, the first impeller includes a first ring plate and a plurality of first blades connected to the first ring plate, the plurality of first blades are arranged at circumferential intervals along the rotation axis of the first impeller, and on a projection plane perpendicular to the rotation axis of the first impeller, the projection of the first blades is located between the inner contour line and the outer contour line of the projection of the first ring plate.

[0018] According to some embodiments of the present invention, the second impeller includes a second ring plate and a plurality of second blades connected to the second ring plate, the plurality of second blades are arranged at circumferential intervals along the rotation axis of the second impeller, and on a projection plane perpendicular to the rotation axis of the second impeller, the projection of the second blades protrudes from the inner contour line of the projection of the second ring plate.

[0019] According to some embodiments of the present invention, the first impeller includes a plurality of first blades arranged at circumferential intervals along the rotation axis of the first impeller, and the second impeller includes a plurality of second blades arranged at circumferential intervals along the rotation axis of the second impeller, and the number of the second blades is greater than the number of the first blades.

[0020] According to some embodiments of the present invention, along the axial direction of the first impeller, the maximum height of the first blade at one end facing the rotation axis of the first impeller is H1, and the maximum height of the second blade at one end facing the rotation axis of the second impeller is H2, satisfying: 0.6*H1≤H2≤0.9*H1.

[0021] According to some embodiments of the present invention, along the axial direction of the first impeller, the minimum height of the first blade at one end away from the rotation axis of the first impeller is H3, and the minimum height of the second blade at one end away from the rotation axis of the second impeller is H4, satisfying: 0.8*H3≤H4<H3.

[0022] According to some embodiments of the present invention, the first impeller includes a plurality of first blades arranged at circumferential intervals along the rotation axis of the first impeller, a second air outlet is formed between two adjacent first blades, and the second air outlet is located at one end away from the rotation axis of the first impeller; the second impeller includes a plurality of second blades arranged at circumferential intervals along the rotation axis of the second impeller, a third air outlet is formed between two adjacent second blades, and the third air outlet is located at one end away from the rotation axis of the second impeller, and an air outlet cross-sectional area of the third air outlet is smaller than an air outlet cross-sectional area of the second air outlet.

[0023] According to some embodiments of the present invention, the first impeller includes a first ring plate and a plurality of first blades connected to the first ring plate, the plurality of first blades are arranged at circumferential intervals along the rotation axis of the first impeller, the first ring plate is provided with a first through hole for air intake, the second impeller includes a second ring plate and a plurality of second blades connected to the second ring plate, the plurality of second blades are arranged at circumferential intervals along the rotation axis of the second impeller, the second ring plate is provided with a second through hole for air intake, and the minimum inner diameter of the first through hole is larger than the minimum inner diameter of the second through hole.

[0024] According to some embodiments of the present invention, a second air outlet connected to the first air outlet is provided on the side of the returner facing the first air outlet, the minimum inner diameter of the second air outlet is D1, the second impeller is provided with a second through hole for air intake, the minimum inner diameter of the second through hole is D2, satisfying: -2mm≤D1-D2≤2mm.

[0025] According to some embodiments of the present invention, the housing includes an air inlet shell and an air outlet volute connected to each other, the air inlet shell forms the first cavity, and the air outlet volute forms the second cavity.

[0026] According to some embodiments of the present invention, an air outlet channel is formed in the air outlet volute, and part of the bottom wall of the air outlet volute is recessed in a direction away from the second impeller to form a groove, and the groove is arranged around the second impeller and forms a partial structure of the air outlet channel.

[0027] According to some embodiments of the present invention, along the air outlet direction of the air outlet channel, the air outlet cross-sectional area of the air outlet channel gradually increases.

[0028] The cleaning device according to the second embodiment of the present invention includes the fan described in the above embodiment.

[0029] The cleaning device according to the embodiment of the present invention has at least the following beneficial effects:

[0030] By setting the first impeller and the second impeller to rotate under the drive of the driving device, the air flow can be sucked into the first cavity from the first air inlet of the housing, and then passes through the air induction channel of the return device, the first air outlet and the second cavity in sequence, and finally blown out from the first air outlet. Since the first impeller and the second impeller adopt the scheme of jointly sucking air, the air flow completes the first stage of compression when passing through the first impeller, and completes the second stage of compression after passing through the second impeller. Therefore, after the air flow passes through the two-stage compression, the fan will obtain a higher vacuum degree and greater suction force. In addition, the first impeller and the second impeller do not need to use a higher speed, which can ensure that the noise will not increase significantly, and mechanical losses can be reduced at low speeds. At the same time, since the first impeller discharges air in its radial direction, it is easy for the air flow to directly hit the side wall of the first cavity, causing air flow turbulence and large air flow losses. Therefore, the air flow is guided to flow toward the second impeller by setting an air induction channel to reduce aerodynamic losses and thereby improve the working efficiency of the fan.

[0031] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0033] Figure 1 This is a structural diagram of a fan according to an embodiment of the present invention;

[0034] Figure 2 is a structural schematic diagram of a fan from another perspective according to an embodiment of the present invention;

[0035] Figure 31 is an exploded schematic diagram of a fan according to an embodiment of the present invention;

[0036] Figure 4 is a cross-sectional view of a fan according to an embodiment of the present invention;

[0037] Figure 5 is a cross-sectional view of an air inlet housing and a return flow device according to an embodiment of the present invention;

[0038] Figure 6 is a top view of a first impeller according to an embodiment of the present invention;

[0039] Figure 7 is a schematic structural diagram of a second impeller according to an embodiment of the present invention;

[0040] Figure 8 is a top view of a second impeller according to an embodiment of the present invention;

[0041] Figure 9 is a cross-sectional view of a first impeller according to an embodiment of the present invention;

[0042] Figure 10 is a cross-sectional view of a second impeller according to an embodiment of the present invention;

[0043] Figure 11 This is an exploded view of an air outlet volute according to an embodiment of the present invention;

[0044] Figure 12 is a side view of a fan according to an embodiment of the present invention;

[0045] Figure 13 yes Figure 12 Cross-sectional view at AA in the middle.

[0046] Reference numerals:

[0047] Fan 1000;

[0048] Housing 100; air inlet housing 110; first air inlet 111; first cavity 112; guide arc surface 113; air outlet volute 120; second cavity 121; first air outlet 122; air outlet channel 123; mounting base 124; upper shell 125; lower shell 126; groove 127; first air outlet 130;

[0049] First impeller 200; first ring plate 210; first through hole 211; first blade 220; first channel 221; first bottom plate 230; second air inlet 240; second air outlet 250; first mounting portion 260;

[0050] Second impeller 300; second ring plate 310; second through hole 311; second blade 320; second channel 321; second bottom plate 330; third air inlet 340; third air outlet 350; second mounting portion 360;

[0051] Returner 400; guide vane 410; air induction channel 420; second air outlet 430; air guide seat 440;

[0052] Rotating shaft 500. DETAILED DESCRIPTION

[0053] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0054] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0055] In the description of the present invention, "several" means one or more, "many" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0056] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0057] Reference Figure 1 and Figure 2 As shown, a fan 1000 according to an embodiment of the present invention can be used in cleaning equipment such as vacuum cleaners and robot vacuums. The fan 1000 includes a housing 100, a first impeller 200, a first air inlet 111, and a first air outlet 122. The first air inlet 111 and the first air outlet 122 are both provided on the housing 100, and the first impeller 200 is provided inside the housing 100. By driving the first impeller 200 to rotate, air can be forced from the first air inlet 111 into the interior of the housing 100 and finally blown out from the first air outlet 122.

[0058] In order to enable the fan 1000 to obtain a higher vacuum degree and greater suction force without significantly increasing the noise, refer to Figure 3 and Figure 4 As shown, in the embodiment of the present invention, the fan 1000 further includes a second impeller 300, a drive device, and a return flow device 400. The drive device is not shown in the figure. A first cavity 112, a second cavity 121, and a first air outlet 130 are also provided in the housing 100. The first air outlet 130 is located between the first cavity 112 and the second cavity 121. The first impeller 200 is disposed in the first cavity 112, and the second impeller 300 is disposed in the second cavity 121. The drive device is driven and connected to the first impeller 200 and the second impeller 300 via a rotating shaft 500, and the first air inlet 111, the first cavity 112, the first air outlet 130, the second cavity 121, and the first air outlet 122 are sequentially connected.

[0059] Reference Figure 5 As shown, the return flow device 400 is disposed within the first cavity 112 and between the first impeller 200 and the second impeller 300. The return flow device 400 is provided with an air induction channel 420, which is used to guide the airflow generated by the first impeller 200 to the second impeller 300. When the driving device drives the first impeller 200 and the second impeller 300 to rotate in the same direction, the airflow enters from the first air inlet 111, then passes through the first cavity 112, the air induction channel 420, the first air outlet 130 and the second cavity 121 in sequence, and finally blows out from the first air outlet 122.

[0060] Since the first impeller 200 and the second impeller 300 are used to jointly inhale air, the airflow completes the first stage of compression when passing through the first impeller 200, and completes the second stage of compression after passing through the second impeller 300. Therefore, after the airflow undergoes two-stage compression, the fan 1000 will obtain a higher vacuum degree and greater suction force. The first impeller 200 and the second impeller 300 do not need to use a higher rotational speed, which can ensure that the noise will not increase significantly, and mechanical losses can be reduced at low rotational speeds. At the same time, since the first impeller 200 discharges air in its radial direction, it is easy for the airflow to directly hit the side wall of the first cavity 112, causing airflow turbulence and large airflow losses. Therefore, by setting an air duct 420 to guide the airflow toward the second impeller 300, aerodynamic losses are reduced, thereby improving the working efficiency of the fan 1000.

[0061] Reference Figure 5 and Figure 13As shown, in an embodiment of the present invention, the returner 400 includes an air guide base 440 and a plurality of guide vanes 410. The plurality of guide vanes 410 are connected to a side of the air guide base 440 facing away from the first impeller 200. The plurality of guide vanes 410 are spaced apart circumferentially about the rotation axis of the first impeller 200. Air induction channels 420 are formed between adjacent guide vanes 410, i.e., a plurality of air induction channels 420 are provided. The plurality of air induction channels 420 are also spaced apart circumferentially about the rotation axis of the first impeller 200, thereby guiding the airflow in multiple directions, thereby improving the uniformity of the air output.

[0062] Reference Figure 4 As shown, in an embodiment of the present invention, the air guide seat 440 protrudes toward the first air outlet 130 on the side away from the first impeller 200, which is conducive to guiding the air flow coming out of the air duct 420 to flow toward the first air outlet 130, making the air flow direction smoother, effectively reducing the air flow loss caused by air flow turbulence, and improving the working efficiency of the fan 1000.

[0063] Continue to refer to Figure 4 As shown, in an embodiment of the present invention, a plurality of guide vanes are connected to the bottom wall of the first cavity, and the bottom wall of the first cavity is inclined toward the first air outlet. Therefore, the upper end of the air induction channel 420 extends toward the first impeller 200, and the lower end of the air induction channel 420 extends toward the first air outlet 130. In other words, along the air inlet direction of the air induction channel 420, the angle between the air induction channel 420 and the axis of the rotating shaft 500 gradually decreases, which is conducive to guiding the airflow through the first air outlet 130 and then entering the second through hole 311 of the second impeller 300, further reducing airflow losses and improving the efficiency of the fan 1000.

[0064] Reference Figure 13 As shown, in an embodiment of the present invention, the air induction channel 420 is arc-shaped, and the multiple air induction channels 420 are distributed in a vortex shape. Because the airflow generated by the first impeller 200 rotates along the sidewalls of the first cavity 112, the arc-shaped and vortex-shaped air induction channels can better guide the direction of the airflow, deflecting the airflow and directing it toward the second impeller 300 at a predetermined angle, effectively avoiding the problem of airflow turbulence caused by the inconsistency between the airflow direction and the direction of the third air inlet 340.

[0065] Reference Figure 4 and Figure 5As shown, in an embodiment of the present invention, a second air outlet 430 is provided on the side of the return flow mechanism 400 facing the first air outlet 130, communicating with the first air outlet 130. The minimum inner diameter of the second air outlet 430 is D1, and the minimum inner diameter of the second through hole 311 of the second impeller 300 is D2, satisfying the following relationship: -2mm≤D1-D2≤2mm. For example, D1 and D2 can be equal. When D1-D2 is less than -2mm, the air outlet cross-sectional area of the second air outlet 430 is too small, resulting in low air outlet efficiency. When D1-D2 is greater than 2mm, the air outlet cross-sectional area of the second air outlet 430 is too large, causing some airflow to impact the inner wall of the housing 100, resulting in airflow turbulence. Therefore, by designing the relationship -2mm≤D1-D2≤2mm, the majority of the airflow guided by the return flow mechanism 400 smoothly enters the second impeller 300, improving air intake efficiency and effectively reducing airflow turbulence.

[0066] Reference Figure 4 As shown, in this embodiment of the present invention, the sidewall of the first cavity 112 is provided with a guide arc surface 113. The guide arc surface 113 is recessed in a direction away from the first impeller 200 and extends to the air inlet end of the air induction channel 420. Because the first impeller 200 is a centrifugal impeller that ejects air in its radial direction, the guide arc surface 113 is provided on the sidewall of the first cavity 112 to guide the airflow into the air induction channel 420, effectively reducing airflow losses and improving the operating efficiency of the fan 1000.

[0067] Reference Figure 3 As shown, in an embodiment of the present invention, the first impeller 200 includes a first ring plate 210, first blades 220, and a first base plate 230. The first ring plate 210 and the first base plate 230 are spaced apart along the axial direction of the first impeller 200. A plurality of first blades 220 are provided and connected between the first ring plate 210 and the first base plate 230. The plurality of first blades 220 are spaced apart around the rotation axis of the first impeller 200. The first ring plate 210 is provided with first through-holes 211 for air intake, and first channels 221 are formed between adjacent first blades 220 for air discharge. The first impeller 200 is a centrifugal impeller, meaning that the first impeller 200 can intake air axially and discharge air radially. When the first impeller 200 rotates, airflow enters through the first through-holes 211, is blown out through the first channels 221 to the sidewalls of the first cavity 112, and then, guided by the air induction channel 420 of the recirculator 400, is blown toward the second impeller 300. Compared with the axial flow impeller solution, the centrifugal impeller can generate higher wind pressure and has higher efficiency, which can improve the suction effect.

[0068] Reference Figure 6 As shown, in the embodiment of the present invention, Figure 6The dashed line in the figure represents the outline of the first blade 220, which is obscured by the first ring plate 210. On a projection plane perpendicular to the rotation axis of the first impeller 200, the projected outline of the first blade 220 lies between the inner and outer projected outlines of the first ring plate 210. Because the first blade 220 is not blocking the first through-hole 211, the air intake area of the first impeller 200 is increased, improving air intake efficiency and enhancing manufacturability with reduced production difficulty.

[0069] Reference Figure 7 As shown, in an embodiment of the present invention, the second impeller 300 includes a second ring plate 310, second blades 320, and a second base plate 330. The second ring plate 310 and the second base plate 330 are spaced apart along the axial direction of the second impeller 300. A plurality of second blades 320 are provided and connected between the second ring plate 310 and the second base plate 330. The plurality of second blades 320 are spaced apart around the rotation axis of the second impeller 300. The second ring plate 310 is provided with second through holes 311 for air intake, and second channels 321 are formed between adjacent second blades 320. The second impeller 300 is a centrifugal impeller, meaning that the second impeller 300 can take in air axially and discharge air radially. When the second impeller 300 rotates, airflow enters through the second through holes 311, is blown out through the second channels 321 to the sidewalls of the second cavity 121, and finally is blown out through the first air outlet 122.

[0070] Reference Figure 7 and Figure 8 As shown, in an embodiment of the present invention, on a projection surface perpendicular to the rotation axis of the second impeller 300, the projection contour line of the second blade 320 protrudes from the inner contour line of the projection of the second ring plate 310 on the side of the rotation axis of the second impeller 300. The purpose is to increase the contact area between the blade and the airflow and improve the ability to do work on the airflow. At the same time, the cross-sectional area of the second channel 321 can be reduced to increase the flow rate of the airflow and increase the suction force. When the fan 1000 is used inside a vacuum cleaner, it can effectively increase the negative pressure effect inside the vacuum cleaner, thereby improving the suction force and dust collection efficiency of the vacuum cleaner. It should be noted that in subsequent embodiments, if not otherwise specified, the fan 1000 is used in a vacuum cleaner as an example for explanation.

[0071] Therefore, the difference between the structures of the first impeller 200 and the second impeller 300 stems from their different functions. The purpose of the first impeller 200 is to achieve a greater air intake and facilitate manufacturing. However, after the airflow passes through the first impeller 200 and is pressurized and accelerated, the second impeller 300 needs to perform further work on the airflow to further increase its velocity. Therefore, the second impeller 300 can be designed so that the end of the second blade 320 facing the rotation axis of the second impeller 300 protrudes from the second through hole 311, thereby increasing the contact area with the airflow, improving the ability to perform work on the airflow, and further increasing the airflow velocity.

[0072] Reference Figure 6 and Figure 8 As shown, in the embodiment of the present invention, the number of first blades 220 is less than the number of second blades 320. For example, the number of first blades 220 is 9, and the number of second blades 320 is 13. Of course, the number of first blades 220 and second blades 320 can also be other numbers, for example, the number of first blades 220 is 7, and the number of second blades 320 is 11. The appropriate number is selected based on the actual situation. It is understood that because the number of second blades 320 is greater than the number of first blades 220, when the maximum outer diameter of the first impeller 200 and the maximum outer diameter of the second impeller 300 are the same, the cross-sectional area of the first channel 221 is greater than the cross-sectional area of the second channel 321. It should be noted that the cross-sectional area refers to the cross-sectional area generated when the first impeller 200 and the second impeller 300 are coaxially arranged and a cross-sectional plane parallel to the rotation axis of the first impeller 200 cuts through the first channel 221 and the second channel 321. Since the cross-sectional area of the second channel 321 is small, the gas flow rate is faster than that of the first channel 221, and more second blades 320 can further increase the contact area with the airflow, improve the efficiency of working on the airflow, effectively increase the negative pressure effect inside the vacuum cleaner, and thus improve the suction force of the vacuum cleaner.

[0073] Reference Figure 9 and Figure 10 As shown, in the embodiment of the present invention, along the axial direction of the first impeller 200, the maximum height of the first blade 220 at one end facing the rotation axis of the first impeller 200 is H1, and the maximum height of the second blade 320 at one end facing the rotation axis of the second blade 320 is H2, satisfying: 0.6*H1≤H2≤0.9*H1, which is equivalent to 0.6≤H2 / H1≤0.9, for example, H2 / H1=0.7, H2 / H1=0.75, or H2 / H1=0.8. It should be noted that the maximum height of the first blade 220 refers to the height between the end of the first blade 220 facing the rotation axis of the first impeller 200 and connected to the highest point of the first ring plate 210 and the first bottom plate 230; the maximum height of the second blade 320 refers to the height between the end of the second blade 320 facing the rotation axis of the second impeller 300 and connected to the highest point of the second ring plate 310 and the second bottom plate 330.

[0074] Among them, the end of the first channel 221 facing the rotation axis of the first impeller 200 is the second air inlet 240, and the end of the second channel 321 facing the rotation axis of the second impeller 300 is the third air inlet 340. Height affects the size of the air inlet area. When H2 / H1 is less than 0.6, the height of the second blade 320 is too low, and the air inlet area of the third air inlet 340 is too small, which can easily lead to air inlet blockage, reduced efficiency, and increased noise and vibration. When H2 / H1 is greater than 0.9, although the air inlet efficiency can be improved, it is difficult to increase the wind speed. Therefore, by rationally designing the relationship between H1 and H2, the air inlet area of the third air inlet 340 is smaller than the air inlet area of the second air inlet 240, which can ensure a certain air inlet efficiency while also increasing the wind speed.

[0075] Continue to refer to Figure 9 As shown, in the embodiment of the present invention, along the axial direction of the first impeller 200, the lowest height of the first blade 220 at the end facing away from the rotation axis of the first impeller 200 is H3, and the lowest height of the second blade 320 at the end facing away from the rotation axis of the second impeller 300 is H4, satisfying the following formula: 0.8*H3≤H4<H3, which is equivalent to 0.8≤H4 / H3<1, for example, H4 / H3=0.85, H4 / H3=0.9, or H4 / H3=0.95. It should be noted that the lowest height of the first blade 220 refers to the height between the end of the first blade 220 facing away from the rotation axis of the first impeller 200 and connected to the lowest point of the first ring plate 210 and the first bottom plate 230; the lowest height of the second blade 320 refers to the height between the end of the second blade 320 facing away from the rotation axis of the second impeller 300 and connected to the lowest point of the second ring plate 310 and the second bottom plate 330.

[0076] The end of the first channel 221 facing away from the rotation axis of the first impeller 200 is the second air outlet 250, and the end of the second channel 321 facing away from the rotation axis of the second impeller 300 is the third air outlet 350. When H4 / H3 is less than 0.8, the cross-sectional area of the third air outlet 350 is too small, which can easily lead to reduced air outlet efficiency and increased noise and vibration. When H4 / H3 is greater than or equal to 1, it is difficult to achieve the effect of increasing wind speed. Therefore, by rationally designing the relationship between H3 and H4, so that the cross-sectional area of the third air outlet 350 is smaller than the cross-sectional area of the second air outlet 250, it is possible to ensure air outlet efficiency while also increasing air outlet speed.

[0077] Reference Figure 6 and Figure 8As shown, in the embodiment of the present invention, the minimum inner diameter of the first through hole 211 is greater than the minimum inner diameter of the second through hole 311. It will be understood that the minimum inner diameters of the first through hole 211 and the second through hole 311 reflect the size of the air inlet area, i.e., the air inlet area of the first through hole 211 is greater than the air inlet area of the second through hole 311. Since the first impeller 200 primarily ensures a large air intake volume, and the second impeller 300 primarily serves to increase airflow velocity, by designing D1 to be greater than D2, the first impeller 200 can ensure a large air intake volume, while the second impeller 300 can increase airflow velocity by reducing the air intake area.

[0078] Reference Figure 3 and Figure 4 As shown, in an embodiment of the present invention, the housing 100 includes an air inlet housing 110 and an air outlet volute 120. The air inlet housing 110 and the air outlet volute 120 are connected. The air inlet housing 110 has a first cavity 112 and a first air inlet 111, and the air outlet volute 120 has a second cavity 121 and a first air outlet 122. The use of the air outlet volute 120 can adapt to the air outlet direction of the second impeller 300, thereby improving the efficiency and performance of the fan 1000.

[0079] Reference Figure 11 and Figure 12 As shown, in the embodiment of the present invention, the air outlet volute 120 includes an upper shell 125 and a lower shell 126, which are connected and define a second cavity 121 between the upper shell 125 and the lower shell 126. The air outlet volute 120 is formed with an air outlet channel 123, and a portion of the bottom wall of the lower shell 126 is concavely formed with a groove 127 along a direction away from the second impeller 300. The groove 127 is arranged around the second impeller 300 and forms a part of the structure of the air outlet channel 123. The air flow can be blown out along the air outlet channel 123, for example, along the Figure 11 Flow in the direction of the dashed arrow.

[0080] It is understood that the cross-sectional area of the outlet volute 120 during air discharge must meet certain requirements and cannot be too large or too small. A large area can cause turbulent airflow, while a small area can cause blockage and reduced efficiency. To ensure that the cross-sectional area of the outlet duct 123 meets the requirements, the groove 127 protrudes radially from the second impeller 300 or away from the second impeller 300. If the groove 127 protrudes radially from the second impeller 300, the radial dimension of the fan 1000 increases, hindering the miniaturization of the fan 1000. If the groove 127 protrudes away from the second impeller 300, the bottom wall of the outlet volute 120 still needs to be equipped with a drive device, which itself occupies a certain position in the axial direction. Therefore, the solution of this embodiment does not increase the axial length of the fan 1000, which facilitates the miniaturization of the fan 1000 and reduces the space occupied by the fan 1000.

[0081] Reference Figure 11 and Figure 12 As shown, in this embodiment of the present invention, the cross-sectional area of the air outlet channel 123 gradually increases along the outlet direction of the air outlet channel 123. This reduces the air outlet velocity and increases the air pressure in the air outlet channel 123. This increased air pressure further enhances the suction power of the vacuum cleaner, facilitates airflow through the vacuum cleaner's duct and filtration system, and improves the cleaning effect.

[0082] In summary, the first impeller 200 mainly ensures that the fan 1000 can have a larger air intake volume; the return flow device 400 plays the role of guiding the direction of the airflow and reducing airflow loss; the second impeller 300 can further increase the speed of the airflow; the air outlet channel 123 can further increase the pressure of the airflow, so that the fan 1000 can obtain a higher vacuum degree and greater suction.

[0083] Reference Figure 2 As shown, in an embodiment of the present invention, the driving device includes a motor, which is not shown in the figure. A mounting base 124 is provided at the bottom of the air outlet volute 120. The motor is fixedly connected to the mounting base 124 and is drivingly connected to the rotating shaft 500. Therefore, the motor can drive the first impeller 200 and the second impeller 300 to rotate synchronously through the rotating shaft 500. In another embodiment of the present invention, the driving device may further include two motors, which respectively drive the first impeller 200 and the second impeller 300 to rotate. The appropriate solution is selected according to the actual situation.

[0084] Reference Figure 9 and Figure 10As shown, in the embodiment of the present invention, the first base plate 230 is provided with a first mounting portion 260, and the second base plate 330 is provided with a second mounting portion 360. The first mounting portion 260 and the second mounting portion 360 are used to be fixedly connected to the rotating shaft 500. The first mounting portion 260 is cylindrical, so the overall strength of the first mounting portion 260 is relatively high, which can ensure the stability of the connection with the rotating shaft 500. The outer wall of the second mounting portion 360 is tapered. Since the second impeller 300 is located between the first impeller 200 and the motor and is connected to the middle of the rotating shaft 500, the strength requirement is lower than that of the first mounting portion 260. Therefore, the tapered design reduces airflow loss and improves the efficiency of the fan 1000.

[0085] A cleaning device according to an embodiment of the present invention includes the fan 1000 of the above embodiment, and the cleaning device can be a vacuum cleaner or a sweeping robot. The cleaning device according to the embodiment of the present invention adopts the fan 1000 of the above embodiment, and by setting the first impeller 200 and the second impeller 300 to rotate under the drive of the driving device, the air flow can be sucked into the first cavity 112 from the first air inlet 111 of the housing 100, and then passes through the air induction channel 420 of the return flow device 400, the first air outlet 130 and the second cavity 121 in sequence, and finally blown out from the first air outlet 122. Due to the scheme of jointly inhaling air by the first impeller 200 and the second impeller 300, the air flow completes the first compression when passing through the first impeller 200, and completes the second compression after passing through the second impeller 300. Therefore, after the air flow undergoes two-stage compression, the fan 1000 will obtain a higher vacuum degree and greater suction force. Moreover, the first impeller 200 and the second impeller 300 do not need to use a higher rotational speed, which can ensure that the noise will not increase significantly, and the mechanical loss can be reduced at a low rotational speed. At the same time, under the guidance of the air duct 420, the aerodynamic loss can be reduced, thereby improving the working efficiency of the fan 1000.

[0086] Since the cleaning device adopts all the technical solutions of the fan 1000 of the above embodiment, it has at least all the beneficial effects brought by the technical solutions of the above embodiment, which will not be described in detail here.

[0087] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the scope of the present invention.

Claims

1. A fan, characterized in that: include: The housing is provided with a first air inlet, a first cavity, a first air outlet, a second cavity and a first air outlet which are connected in sequence; a first impeller rotatably disposed in the first cavity; a second impeller rotatably disposed in the second cavity; a driving device, drivingly connected to the first impeller and the second impeller; A return flow device is provided in the first cavity and located between the first impeller and the second impeller. The return flow device is formed with an air induction channel, and the air induction channel is used to guide the airflow generated by the first impeller to the second impeller.

2. The fan according to claim 1, characterized in that The returner includes an air guide seat and a plurality of guide blades. The plurality of guide blades are connected to the side of the air guide seat away from the first impeller and are arranged at circumferential intervals along the rotation axis of the first impeller. The air duct is formed between adjacent guide blades.

3. The fan according to claim 2, characterized in that The side of the air guide seat facing away from the first impeller protrudes toward the first air outlet.

4. The fan according to claim 2, characterized in that: The plurality of guide vanes are connected to the bottom wall of the first cavity, and the bottom wall of the first cavity is inclined toward the first air outlet.

5. The fan according to claim 1, characterized in that A guide arc surface is provided on the side wall of the first cavity. The guide arc surface is recessed in a direction away from the first impeller and extends to the air inlet end of the air induction channel.

6. The fan according to claim 1, characterized in that The first impeller includes a first ring plate and a plurality of first blades connected to the first ring plate. The plurality of first blades are arranged at intervals along the circumferential direction of the rotation axis of the first impeller. On a projection plane perpendicular to the rotation axis of the first impeller, the projection of the first blades is located between the inner contour line and the outer contour line of the projection of the first ring plate.

7. The fan according to claim 1 or 6, characterized in that: The second impeller includes a second ring plate and a plurality of second blades connected to the second ring plate. The plurality of second blades are arranged at intervals along the circumference of the rotation axis of the second impeller. On a projection plane perpendicular to the rotation axis of the second impeller, the projection of the second blades protrudes from the inner contour line of the projection of the second ring plate.

8. The fan according to claim 1, characterized in that The first impeller includes a plurality of first blades spaced circumferentially along the rotation axis of the first impeller, and the second impeller includes a plurality of second blades spaced circumferentially along the rotation axis of the second impeller, wherein the number of the second blades is greater than the number of the first blades.

9. The fan according to claim 8, characterized in that Along the axial direction of the first impeller, the maximum height of the first blade at one end facing the rotation axis of the first impeller is H1, and the maximum height of the second blade at one end facing the rotation axis of the second impeller is H2, satisfying: 0.6*H1≤H2≤0.9*H1.

10. The fan according to claim 8, characterized in that Along the axial direction of the first impeller, the lowest height of the first blade away from the rotation axis of the first impeller is H3, and the lowest height of the second blade away from the rotation axis of the second impeller is H4, satisfying: 0.8*H3≤H4<H3.

11. The fan according to claim 1, characterized in that The first impeller includes a plurality of first blades arranged at circumferential intervals along the rotation axis of the first impeller, a second air outlet is formed between two adjacent first blades, and the second air outlet is located at one end of the first blade away from the rotation axis of the first impeller. The second impeller includes a plurality of second blades arranged at circumferential intervals along the rotation axis of the second impeller, a third air outlet is formed between two adjacent second blades, and the third air outlet is located at one end of the second blade away from the rotation axis of the second impeller. The air outlet cross-sectional area of the third air outlet is smaller than the air outlet cross-sectional area of the second air outlet.

12. The fan according to claim 1, characterized in that The first impeller includes a first ring plate and a plurality of first blades connected to the first ring plate, the plurality of first blades are arranged at circumferential intervals along the rotation axis of the first impeller, the first ring plate is provided with a first through hole for air intake, the second impeller includes a second ring plate and a plurality of second blades connected to the second ring plate, the plurality of second blades are arranged at circumferential intervals along the rotation axis of the second impeller, the second ring plate is provided with a second through hole for air intake, and the minimum inner diameter of the first through hole is greater than the minimum inner diameter of the second through hole.

13. The fan according to claim 1, characterized in that The returner is provided with a second air outlet connected to the first air outlet on the side facing the first air outlet, and the minimum inner diameter of the second air outlet is D1. The second impeller is provided with a second through hole for air intake, and the minimum inner diameter of the second through hole is D2, satisfying: -2mm≤D1-D2≤2mm.

14. The fan according to claim 1, characterized in that The housing includes an air inlet shell and an air outlet volute connected to each other. The air inlet shell forms the first cavity, and the air outlet volute forms the second cavity.

15. The fan according to claim 14, characterized in that An air outlet channel is formed in the air outlet volute, and part of the bottom wall of the air outlet volute is recessed in a direction away from the second impeller to form a groove. The groove is arranged around the second impeller and forms a partial structure of the air outlet channel.

16. The fan according to claim 15, characterized in that Along the air outlet direction of the air outlet channel, the air outlet cross-sectional area of the air outlet channel gradually increases.

17. Cleaning equipment, characterized in that: The invention comprises the wind turbine according to any one of claims 1 to 16.

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