Mixed flow impeller, power system and bladeless fan

Abstract

The application provides a mixed flow impeller, a power system and a bladeless fan, and relates to the technical field of household appliance parts. The mixed flow impeller comprises a hub and a plurality of main blades. The plurality of main blades are arranged on the hub and surround a central axis. The main blade comprises a leading edge and a trailing edge. The included angle between the projection of the leading edge of the main blade on a first plane and the projection of the trailing edge of the main blade on the first plane is alpha 1. Alpha 1 satisfies 60 DEG <= alpha 1 <= 90 DEG. In this way, the wrap angle of the main blade can be ensured to be within a suitable range under the condition that the height of the main blade is unchanged. When the mixed flow impeller rotates around the central axis, the airflow can flow approximately in the axial direction, the flow of the airflow is increased, the airflow has sufficient wind pressure, the energy efficiency is improved, the noise is reduced, and thus the performance of the small-volume power system is improved.

Description

Technical Field

[0001] This application relates to the field of home appliance component technology, and in particular to a diagonal flow impeller, a power system, and a bladeless fan. Background Technology

[0002] Currently, functional integration has become an important development trend for bladeless fans. For example, bladeless fans are gradually integrating multiple functions such as air purification, heating, and humidification.

[0003] However, the addition of additional functions often leads to increased airflow resistance, and the overall size of the product is often limited by the user's needs for product storage or appearance. This results in a smaller space for the design of the power system, which in turn reduces the overall performance of the bladeless fan and causes problems such as low airflow speed, small air volume, and high operating noise. Summary of the Invention

[0004] This application provides a mixed-flow impeller, a power system, and a bladeless fan, which can solve the technical problem of overall performance degradation of bladeless fans.

[0005] In a first aspect, embodiments of this application provide a mixed-flow impeller, comprising: A wheel hub has a central axis; Multiple main blades are disposed on the hub, and the multiple main blades are arranged around the central axis. Each main blade includes a leading edge and a trailing edge. The projection of the leading edge onto the first plane forms an angle with the projection of the trailing edge onto the first plane, the angle being α1, where α1 satisfies: 60°≤α1≤90°, and the first plane is perpendicular to the central axis.

[0006] In some embodiments, the leading edge has a first inner end point near the hub and a first outer end point away from the hub, the trailing edge has a second inner end point near the hub and a second outer end point away from the hub, and the main blade further includes a first profile near the hub and a second profile away from the hub, the first inner end point and the second inner end point being located on the first profile, and the first outer end point and the second outer end point being located on the second profile; Wherein, the angle between the tangent of the first profile at the first inner endpoint and the first plane is β1, and β1 satisfies: 70°≤β1≤80°; The angle between the tangent of the first profile at the second inner endpoint and the first plane is β2, and β2 satisfies: 80°≤β2≤90°; The angle between the tangent of the second shape at the first outer endpoint and the first plane is β3, where β3 satisfies: 70°≤β3≤80°; The angle between the tangent of the second profile at the second outer endpoint and the first plane is β4, and β4 satisfies: 30°≤β4≤40°.

[0007] In some embodiments, the line connecting the first inner endpoint and the first outer endpoint is a leading edge line with a length of L1, and the line connecting the second inner endpoint and the second outer endpoint is a trailing edge line with a length of L2. L1 and L2 satisfy: 0.5L1≤L2≤L1.

[0008] In some embodiments, the angle formed by the leading edge line and the central axis is A1, and the angle formed by the trailing edge line and the central axis is A2, wherein A1 and A2 satisfy: 80°≤A1≤100°, 35°≤A2≤60°.

[0009] In some embodiments, along a direction perpendicular to the central axis, the distance between the first inner endpoint and the central axis is R1, the distance between the first outer endpoint and the central axis is R2, the distance between the second inner endpoint and the central axis is R3, and the distance between the second outer endpoint and the central axis is R4. Among them, R1, R2, R3 and R4 satisfy: 0.1R3≤R1≤0.35R3, 0.65R4≤R2≤0.85R4, 0.55R4≤R3≤0.8R4.

[0010] In some embodiments, the height of the main blade extending along the central axis is H1, and the ratio of H1 to R4 satisfies: 0.4≤H1 / R4≤1.

[0011] In some embodiments, the oblique flow impeller further includes a plurality of flow-dividing blades, all of which are disposed on the hub and arranged around the central axis, with one flow-dividing blade located between two adjacent main blades.

[0012] In some embodiments, at least one of the trailing edge of the main blade and the trailing edge of the diverter blade is provided with a plurality of trailing edge serrations; The plurality of trailing edge serrations are arranged sequentially in a direction away from the wheel hub, and the height of the trailing edge serrations is greater than or equal to the width of the trailing edge serrations.

[0013] Secondly, embodiments of this application provide a power system, which includes: The casing has a receiving cavity; The oblique flow impeller described above is disposed within the receiving cavity; A drive unit is mounted on the housing, and the output shaft of the drive unit is driven to drive the diagonal flow impeller. The drive unit is used to drive the diagonal flow impeller to rotate around the central axis.

[0014] In some embodiments, the housing has an air outlet, and the air outlet is provided with a plurality of stationary guide vanes, which are arranged sequentially at intervals around the central axis; Wherein, along the extension direction of the central axis, the height of the stationary guide vane is H2, and H2 satisfies: 35mm≤H2≤65mm.

[0015] In some embodiments, the trailing edge has a second inner end point near the hub and a second outer end point away from the hub, and the midpoint of the line connecting the second inner end point and the second outer end point is a first center point; Wherein, along the extension direction of the central axis, the distance between the first center point and the stationary guide vane is H3, and H3 satisfies: 10mm≤H3≤35mm.

[0016] In some embodiments, the trailing edge has a second inner end point near the hub and a second outer end point away from the hub. The distance between the second inner end point and the central axis is R3 in a direction perpendicular to the central axis. The clearance between the oblique flow impeller and the housing is W. W and R3 satisfy: 1.5mm≤W≤0.15R3.

[0017] In some embodiments, the housing has an air outlet communicating with the receiving cavity, and the housing includes a first annular wall and a second annular wall disposed around the central axis, the air outlet being formed between the first annular wall and the second annular wall, the first annular wall being located inside the second annular wall; The trailing edge has a second inner end point near the hub and a second outer end point away from the hub. In a direction perpendicular to the central axis, the distance between the second inner end point and the central axis is R3, the distance between the second outer end point and the central axis is R4, the distance between the first annular wall and the central axis is R5, and the distance between the second annular wall and the central axis is R6. R3, R4, R5, and R6 satisfy: R3≤R5≤1.35R3, R4≤R6≤1.3R4.

[0018] Thirdly, embodiments of this application provide a bladeless fan, which includes: The base is equipped with a filter structure; The power system described above has an air inlet and an air outlet, the power system is mounted on the base, and the air inlet is connected to the filter structure; The air duct housing has an air outlet duct, the air duct housing is installed in the power system, and the air outlet duct is connected to the air outlet.

[0019] In some embodiments, the air outlet duct extends along the extension direction of the central axis, and the air outlet duct has a first connecting port communicating with the air outlet and a second connecting port for blowing air outward, the air outlet direction of the second connecting port is set at an angle to the extension direction of the central axis, and the flow area of ​​the air outlet duct gradually decreases in the direction away from the first connecting port.

[0020] In some embodiments, the second communication port includes a plurality of sub-ports, which are arranged sequentially along the extension direction of the central axis; The height of the sub-port along the central axis is H4, and the height H4 of the multiple sub-ports decreases sequentially in the direction away from the first connecting port.

[0021] In some embodiments, the duct shell has multiple perforations, all of which are connected to the air outlet duct and penetrate the outer surface of the duct shell. The diameter of the perforations is D, where D satisfies: 3mm≤D≤10mm.

[0022] In some embodiments, the bladeless fan further includes a sound-absorbing element disposed on the outer surface of the duct housing and covering the plurality of perforations.

[0023] The mixed-flow impeller, power system, and bladeless fan based on the embodiments of this application have at least the following beneficial effects: By arranging multiple main blades around the central axis on the outer surface of the hub, and with each main blade including a leading edge and a trailing edge, the projection of the leading edge onto the first plane and the projection of the trailing edge onto the first plane form an angle α1, where α1 satisfies: 60°≤α1≤90°. In this way, with the main blade height remaining constant, the wrap angle of the main blades can be ensured to be within a suitable range. When the oblique flow impeller rotates around the central axis, the airflow can be made to flow approximately axially, increasing the airflow rate and ensuring sufficient wind pressure, thereby improving energy efficiency, reducing noise, and thus enhancing the performance of the small-volume power system. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 A three-dimensional structural schematic diagram of a diagonal flow impeller provided for an embodiment of this application; Figure 2 A three-dimensional structural diagram of a power system provided in an embodiment of this application; Figure 3 A front view of the power system provided in an embodiment of this application; Figure 4 for Figure 3 Schematic diagram of the cross-sectional structure at point AA; Figure 5 A simplified projection diagram of a diagonal flow impeller on a first plane provided in an embodiment of this application; Figure 6 A simplified schematic diagram of the structure of the mixed-flow impeller provided in the embodiments of this application; Figure 7 A simplified cross-sectional view of the oblique flow impeller in the meridional plane provided in the embodiments of this application; Figure 8 A simplified cross-sectional view of the oblique flow impeller in the meridional plane provided in the embodiments of this application is shown, and the first set of parameters is labeled. Figure 9 A simplified cross-sectional diagram of the oblique flow impeller in the meridional plane provided in the embodiments of this application is shown, and the second set of parameters is marked. Figure 10 A simplified schematic diagram of the tail-edge serrations provided in the embodiments of this application; Figure 11 A three-dimensional structural diagram of a bladeless fan provided in an embodiment of this application; Figure 12 A schematic diagram of airflow within an air outlet duct provided in an embodiment of this application; Figure 13 A front view of the air duct shell provided in an embodiment of this application; Figure 14 This is a schematic diagram of a duct shell with multiple perforations provided in an embodiment of this application. Figure 15 This is a schematic diagram of the structure of the sound-absorbing component provided in the embodiment of this application, which is disposed on the air duct shell.

[0026] Explanation of reference numerals in the attached figures: 1000, bladeless fan; 100. Power system; 10. Oblique flow impeller; 101. Impeller flow channel; 1. Hub; 2. Main blade; 21. Leading edge; 211. First inner end point; 212. First outer end point; 22. Trailing edge; 221. Second inner end point; 222. Second outer end point; 223. First center point; 23. First profile; 24. Second profile; 25. Leading edge line; 26. Trailing edge line; 27. Trailing edge serrations; 3. Flow splitter blade; 20. Housing; 201. Receiving cavity; 202. Air outlet; 203. Air inlet; 204. Stationary guide vane; 205. First annular wall; 206. Second annular wall; 30. Driving components; 200. Base; 2001. Filter structure; 300. Air duct housing; 301. Air outlet duct; 302. First connecting port; 303. Second connecting port; 3031. Sub-connecting port; 304. Perforation; 400. Sound-absorbing parts; N, central axis. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] Firstly, please refer to Figure 1 This document describes the detailed structure of a diagonal flow impeller 10 provided in an embodiment of this application. To facilitate a deeper understanding of the structure of the diagonal flow impeller 10, the basic structure of the power system 100 employing this diagonal flow impeller 10 is briefly described below.

[0029] Please see Figures 2 to 4 This application provides a power system 100, which includes a housing 20, a diagonal flow impeller 10, and a drive member 30. The housing 20 has a receiving cavity 201, the diagonal flow impeller 10 is disposed in the receiving cavity 201, the drive member 30 is installed in the housing 20, and the output shaft of the drive member 30 is drivenly connected to the diagonal flow impeller 10. The drive member 30 can drive the diagonal flow impeller 10 to rotate around the central axis N. The diagonal flow impeller 10 can draw external airflow from the air inlet 203 of the power system 100 into the receiving cavity 201 and blow the airflow out from the air outlet 202 of the power system 100.

[0030] Please see Figure 1 and Figure 5 The oblique flow impeller 10 in this embodiment includes a hub 1 and a plurality of main blades 2. The hub 1 has a central axis N, and the plurality of main blades 2 are disposed on the outer surface of the hub 1 and arranged around the central axis N. The main blades 2 include a leading edge 21 and a trailing edge 22. The projection of the leading edge 21 on the first plane and the projection of the trailing edge 22 on the first plane form an angle α1, which satisfies: 60°≤α1≤90°. The first plane is perpendicular to the central axis N.

[0031] Optionally, the hub 1 is a supporting component of the diagonal flow impeller 10. The hub 1 has a shaft hole at its center, and the axis of the shaft hole is collinear with the central axis N. The shaft hole can be inserted and engaged with the output shaft of the drive member 30, so that the drive member 30 can drive the hub 1 to rotate. Multiple main blades 2 can be installed on the outer surface of the hub 1. The hub 1 can transmit the rotational power of the drive member 30 to all the main blades 2, and the hub 1 can withstand the centrifugal force and aerodynamic load generated by rotation.

[0032] Multiple main blades 2 are disposed on the outer surface of the hub 1, and the multiple main blades 2 are spirally arranged around the central axis N. An impeller flow channel 101 is formed between two adjacent main blades 2. When the driving member 30 drives the oblique flow impeller 10 to rotate, the multiple main blades 2 can do work to draw external air into the impeller flow channel 101, and the airflow can flow along the main impeller to the air outlet 202. The shape of the main blades 2 can directly affect the flow state of the airflow in the impeller flow channel 101.

[0033] In this embodiment, the multiple main blades 2 have the same shape. The main blade 2 includes a leading edge 21 and a trailing edge 22 arranged along the airflow direction. The leading edge 21 is the position where the airflow first contacts the main blade 2, and the trailing edge 22 is the position where the airflow leaves the main blade 2. The angle formed by the projection of the leading edge 21 onto the first plane and the projection of the trailing edge 22 onto the first plane is α1. The angle α1 is the wrap angle of the main blade 2. When the height of the main blade 2 remains unchanged, the angle α1 is mainly used to limit the curvature, coverage area and turning direction of the airflow in the impeller channel 101 of the main blade 2.

[0034] More specifically, when α1 > 90°, the wrap angle of the main blade 2 is too large, causing the main blade 2 to wrap too long around the circumference of the oblique flow impeller 10, and the curvature of the main blade 2 is also too large. This results in excessive deflection of the airflow within the impeller channel 101, leading to excessive flow losses. When α1 < 60°, the wrap angle of the main blade 2 is too small, causing the main blade 2 to wrap too little around the circumference of the oblique flow impeller 10, and the curvature of the main blade 2 is also too small. This results in fewer airflow deflections and a smaller pressure rise. Therefore, when 60° ≤ α1 ≤ 90°, the airflow can flow approximately axially within the impeller channel 101, resulting in low resistance within the impeller channel 101, increased airflow rate, and sufficient pressure rise. This improves energy efficiency, reduces noise, and enhances the performance of the small-volume power system 100.

[0035] Please see Figure 1 and Figure 6In some embodiments, the leading edge 21 has a first inner endpoint 211 near the hub 1 and a first outer endpoint 212 away from the hub 1, the trailing edge 22 has a second inner endpoint 221 near the hub 1 and a second outer endpoint 222 away from the hub 1, and the main blade 2 further includes a first profile 23 near the hub 1 and a second profile 24 away from the hub 1. The first inner endpoint 211 and the second inner endpoint 221 are both located on the first profile 23, and the first outer endpoint 212 and the second outer endpoint 222 are both located on the second profile 24; wherein, the first profile 23 is located on the first inner endpoint 211 near the hub 1 and a second outer endpoint 212 away from the hub 1. The angle between the tangent at endpoint 211 and the first plane is β1, where β1 satisfies: 70°≤β1≤80°; the angle between the tangent at the second inner endpoint 221 of the first shape line 23 and the first plane is β2, where β2 satisfies: 80°≤β2≤90°; the angle between the tangent at the first outer endpoint 212 of the second shape line 24 and the first plane is β3, where β3 satisfies: 70°≤β3≤80°; the angle between the tangent at the second outer endpoint 222 of the second shape line 24 and the first plane is β4, where β4 satisfies: 30°≤β4≤40°. In this embodiment, the first inner endpoint 211 is the endpoint of the main blade 2 closest to the hub 1 at the leading edge 21, the first outer endpoint 212 is the endpoint of the main blade 2 furthest from the hub 1 at the leading edge 21, the second inner endpoint 221 is the endpoint of the main blade 2 closest to the hub 1 at the trailing edge 22, and the second outer endpoint 222 is the endpoint of the main blade 2 furthest from the hub 1 at the trailing edge 22. The first inner endpoint 211, the first outer endpoint 212, the second inner endpoint 221, and the second outer endpoint 222 are the four endpoints at the four corners of the main blade 2. The first profile 23 is the profile tangent between the main blade 2 and the outer surface of the hub 1, and the second profile 24 is the profile of the outermost edge of the main blade 2 on the side furthest from the hub 1. The first inner endpoint 211 and the second inner endpoint 221 are both located on the first profile 23, and the first outer endpoint 212 and the second outer endpoint 222 are both located on the second profile 24.

[0036] Among them, the angle formed by the tangent of the first profile line 23 at the first inner end point 211 and the first plane is β1, the angle formed by the tangent of the first profile line 23 at the second inner end point 221 and the first plane is β2, the angle formed by the tangent of the second profile line 24 at the first outer end point 212 and the first plane is β3, and the angle formed by the tangent of the second profile line 24 at the second outer end point 222 and the first plane is β4. α1, β1, β2, β3 and β4 satisfy: 60°≤α1≤90°, 70°≤β1≤80°, 80°≤β2≤90°, 70°≤β3≤80° and 30°≤β4≤40°. The above four angles and the wrap angle α1 of the main blade 2 are important parameters constituting the blade shape of the main blade 2.

[0037] The included angle β1 can be regarded as the inlet angle of the main blade 2 at the first inner end point 211, and the included angle β3 can be regarded as the inlet angle of the main blade 2 at the first outer end point 212. When the driving member 30 drives the oblique flow impeller 10 to rotate, the external airflow enters the impeller flow channel 101 approximately along the axial direction of the oblique flow impeller 10. When β1 and β3 satisfy: 70°≤β1≤80°, 70°≤β3≤80°, the inlet angle of the main blade 2 and the incoming flow angle of the external airflow (the inflow angle of the airflow relative to the rotation direction of the oblique flow impeller 10 before the airflow hits the leading edge 21 of the main blade 2) have a high degree of matching, that is, the inlet angle of the main blade 2 and the incoming flow angle are approximately equal, so that the airflow can enter the impeller flow channel 101 more smoothly, reduce the impact loss between the airflow and the main blade 2, and thus reduce the vortex and noise generated by the airflow in the impeller flow channel 101.

[0038] The included angle β2 can be regarded as the exit angle of the main blade 2 at the second inner end point 221, and the included angle β4 can be regarded as the exit angle of the main blade 2 at the second outer end point 222. The exit angle determines the direction in which the airflow is thrown out when it leaves the main blade 2. When β2 and β4 satisfy: 80°≤β2≤90°, 30°≤β4≤40°, the exit angle of the part of the trailing edge 22 of the main blade 2 near the hub 1 is large enough to ensure a large air volume and relatively small flow loss of the outflowing air, which can reduce noise. On the other hand, the exit angle of the part of the trailing edge 22 of the main blade 2 away from the hub 1 is small enough to make the main blade 2 more capable of doing work, thereby increasing the pressure of the airflow in the impeller flow channel 101.

[0039] Thus, the shape of the main blade 2 can be fitted by the above four included angles and the wrap angle. The main blade 2 fitted within the range of the above four included angles and the wrap angle can improve the aerodynamic performance of the oblique flow impeller 10. When the airflow passes through the impeller flow channel 101 between two adjacent main blades 2, the airflow can flow more smoothly along the main blade 2, which can improve the air volume and efficiency. In addition, there are fewer vortices in the impeller flow channel 101, which can reduce noise and thus improve the overall performance of the bladeless fan 1000.

[0040] Please see Figure 7 and Figure 8 In some embodiments, the line connecting the first inner endpoint 211 and the first outer endpoint 212 is the leading edge line 25, and the length of the leading edge line 25 is L1. The connection between the second inner endpoint 221 and the second outer endpoint 222 is the trailing edge line 26, and the length of the trailing edge line 26 is L2. L1 and L2 satisfy: 0.5L1≤L2≤L1.

[0041] It should be noted that in the process of designing the oblique flow impeller 10, the outline shape of the main blade 2 needs to be determined on the meridional plane of the oblique flow impeller 10. The outline shape of the main blade 2 includes four curves: leading edge line 25, trailing edge line 26, first profile line 23, and second profile line 24. The leading edge line 25, first profile line 23, trailing edge line 26, and second profile line 24 are connected in sequence, and the leading edge line 25 is connected to the second profile line 24, so that the leading edge line 25, first profile line 23, trailing edge line 26, and second profile line 24 together form the outline shape of the main blade 2.

[0042] In this embodiment, the distance between the first profile 23 and the second profile 24 is the radial width of the main blade 2. The radial width of the main blade 2 gradually decreases along the direction of airflow entering the impeller channel 101, making the impeller channel 101 gradually contract. After entering the impeller channel 101, the airflow is accelerated inside the impeller channel 101, thereby improving the pressure resistance of the oblique flow impeller 10 and reducing airflow backflow. However, if the impeller channel 101 contracts too much, it will lead to excessive resistance and a significant reduction in airflow. Thus, when 0.5L1≤L2≤L1, it ensures that the airflow has sufficient pressure within the impeller channel 101, reducing airflow backflow, while also ensuring sufficient outlet airflow.

[0043] Please see Figure 7 In some embodiments, the angle formed by the leading edge line 25 and the central axis N is A1, and the angle formed by the trailing edge line 26 and the central axis N is A2. A1 and A2 satisfy: 80°≤A1≤100°, 35°≤A2≤60°.

[0044] Optionally, the leading edge 25 is the air inlet edge of the main blade 2. Since the oblique flow impeller 10 is used in the power system 100, the oblique flow impeller 10 is axially inlet. Therefore, the angle between the leading edge 25 and the central axis N should not be too small. When 80°≤A1≤100°, the airflow can enter the impeller flow channel 101 more smoothly and the impact loss between the airflow and the main blade 2 can be reduced.

[0045] The trailing edge 26 is the outlet edge of the main blade 2 and also the outlet boundary of the impeller flow channel 101. Since the oblique flow impeller 10 is used in the power system 100, the airflow needs to move along the axial direction after leaving the oblique flow impeller 10. Therefore, the angle between the trailing edge 26 and the central axis N should not be too small. When 35°≤A2≤60°, the main blade 2 can do enough work on the airflow and guide the airflow to flow smoothly along the axial direction.

[0046] Please see Figure 7 and Figure 8In some embodiments, along a direction perpendicular to the central axis N, the distance between the first inner endpoint 211 and the central axis N is R1, the distance between the first outer endpoint 212 and the central axis N is R2, the distance between the second inner endpoint 221 and the central axis N is R3, and the distance between the second outer endpoint 222 and the central axis N is R4; wherein R1, R2, R3 and R4 satisfy: 0.1R3≤R1≤0.35R3, 0.65R4≤R2≤0.85R4, 0.55R4≤R3≤0.8R4.

[0047] It should be noted that when the diagonal flow impeller 10 is applied to the power system 100, the diagonal flow impeller 10 is installed inside the housing 20 of the power system 100. In order to prevent the diagonal flow impeller 10 from colliding with the housing 20 when it rotates, there needs to be a certain gap between the main blade 2 of the diagonal flow impeller 10 and the inner wall surface of the housing 20. The inner contour dimension of the housing 20 constrains the outer contour dimension of the diagonal flow impeller 10.

[0048] The distance R4 between the second outer end point 222 and the central axis N is the maximum distance between the main blade 2 and the central axis N. Within the limits of the internal space of the casing 20, the larger the value of R4, the better. A sufficiently large R4 can reduce the rotational speed of the diagonal flow impeller 10, thereby reducing noise. Furthermore, when 0.1R3≤R1≤0.35R3, 0.65R4≤R2≤0.85R4, and 0.55R4≤R3≤0.8R4, under this size structure, the radial dimension of the inlet end of the diagonal flow impeller 10 is smaller than the radial dimension of the outlet end. This allows the airflow to smoothly enter the impeller channel 101 and accelerate, while simultaneously achieving effective diffusion work during the rotation of the diagonal flow impeller 10. This ensures both the axial air delivery capacity of the diagonal flow impeller 10 and reduces noise.

[0049] Please see Figures 7 to 9 In some embodiments, the height of the main blade 2 extending along the central axis N is H1, and the ratio of H1 to R4 satisfies: 0.4≤H1 / R4≤1.

[0050] In this embodiment, when the mixed-flow impeller 10 is applied to the power system 100, in order to adapt to the needs of miniaturization of the overall structure of the power system 100, the height H1 of the main blade 2 is reduced. In order to compensate for the reduction in the working surface of the main blade 2 due to the reduction in the height of the main blade 2, the radial width R4 of the main blade 2 is appropriately increased. When 0.4≤H1 / R4≤1, the space required for installing the mixed-flow impeller 10 can be reduced, and the main blade 2 can be ensured to have sufficient working surface.

[0051] Please see Figure 1In some embodiments, the diagonal flow impeller 10 also includes a plurality of diverter blades 3, which are all disposed on the hub 1 and arranged around the central axis N. One diverter blade 3 is located between two adjacent main blades 2.

[0052] Optionally, a splitting blade 3 can be added between two adjacent main blades 2 to divide a relatively wide impeller channel 101 into two sub-channels, so that the airflow is more evenly distributed in the impeller channel 101, which can reduce the probability of low-speed zone and backflow zone in the impeller channel 101, and thus the airflow in the impeller channel 101 is more stable.

[0053] Furthermore, without significantly increasing the flow resistance of the impeller channel 101, the splitting blade 3 can increase the working area and number of times the oblique flow impeller 10 performs work on the airflow, thereby improving the overall pressure boosting effect of the oblique flow impeller 10. In addition, the splitting blade 3 also shares part of the aerodynamic load of the main blade 2, making the pressure distribution on the surface of the main blade 2 more uniform, reducing airflow separation and turbulent pulsation, which is beneficial to reducing operating noise.

[0054] Please see Figure 1 and Figure 10 In some embodiments, at least one of the trailing edge 22 of the main blade 2 and the trailing edge 22 of the splitter blade 3 is provided with a plurality of trailing edge serrations 27; wherein, the plurality of trailing edge serrations 27 are arranged sequentially in a direction away from the hub 1, and the height of the trailing edge serrations 27 is greater than or equal to the width of the trailing edge serrations 27.

[0055] In this embodiment, the trailing edge 22 of the main blade 2 is provided with a plurality of trailing edge serrations 27, and the plurality of trailing edge serrations 27 are arranged sequentially in the direction away from the hub 1, and the height d1 of the trailing edge serrations 27 is greater than or equal to the width d2 of the trailing edge serrations 27, so that the trailing edge serrations 27 can divide the large-scale eddies that fall off the trailing edge 22 of the main blade 2 into a plurality of small eddies, reduce the pressure pulsation caused by the eddy shedding, and significantly reduce the eddy noise and broadband noise when the oblique flow impeller 10 rotates.

[0056] In some other embodiments, the trailing edge 22 of the splitter blade 3 can also be provided with multiple trailing edge serrations 27, and the multiple trailing edge serrations 27 are arranged sequentially in the direction away from the hub 1, and the height of the trailing edge serrations 27 is greater than or equal to the width of the trailing edge serrations 27. The trailing edge serrations 27 on the splitter blade 3 can also reduce the noise when the diagonal flow impeller 10 rotates. Of course, both the main blade 2 and the splitter blade 3 can be provided with trailing edge serrations 27.

[0057] Secondly, please refer to Figures 2 to 4The present application provides a power system 100, which includes a housing 20, the aforementioned diagonal flow impeller 10, and a drive member 30. The housing 20 has a receiving cavity 201, the diagonal flow impeller 10 is disposed in the receiving cavity 201, the drive member 30 is mounted on the housing 20, and the output shaft of the drive member 30 is drivenly connected to the diagonal flow impeller 10. The drive member 30 is used to drive the diagonal flow impeller 10 to rotate around the central axis N.

[0058] Optionally, the housing 20 also has an air outlet 202 and an air inlet 203 communicating with the receiving cavity 201. The air outlet 202 and the air inlet 203 are arranged along the extension direction of the central axis N. When the diagonal flow impeller 10 rotates in the receiving cavity 201, it can drive the airflow from the air inlet 203 into the receiving cavity 201 and drive the airflow out from the air outlet 202.

[0059] In this embodiment, the power system 100 also includes a bracket, which is installed at the air outlet 202 of the housing 20. The drive unit 30 is installed on the bracket, and the output shaft of the drive unit 30 is drivenly connected to the diagonal flow impeller 10. The drive unit 30 can be a rotary motor, and the drive unit 30 can drive the diagonal flow impeller 10 to rotate. The beneficial effects of the power system 100 in this application are the same as the beneficial effects of the diagonal flow impeller 10 in this application, and will not be described in detail here.

[0060] Please see Figure 7 and Figure 9 In some embodiments, the housing 20 has an air outlet 202, and a plurality of stationary guide vanes 204 are provided at the air outlet 202. The plurality of stationary guide vanes 204 are arranged in sequence at intervals around the central axis N. The height of the stationary guide vanes 204 along the extension direction of the central axis N is H2, and H2 satisfies: 35mm≤H2≤65mm.

[0061] Optionally, the air outlet 202 is an annular opening, and multiple stationary guide vanes 204 are arranged sequentially and at intervals around the central axis N within the air outlet 202, and the stationary guide vanes 204 extend along the extension direction of the central axis N.

[0062] Understandably, the airflow discharged from the oblique flow impeller 10 has a circumferential swirling velocity. Multiple stationary guide vanes 204 can eliminate the swirling component of the discharged airflow, thereby rectifying the rotating airflow discharged from the oblique flow impeller 10, so that the airflow can flow out smoothly along the axial direction, reducing the pressure loss at the air outlet 202. At the same time, the stationary guide vanes 204 can also suppress the vortex at the air outlet 202 and reduce aerodynamic noise.

[0063] When H2 < 35mm, the axial height of the stationary guide vane 204 is too small, resulting in poor rectification of the rotating airflow discharged from the oblique flow impeller 10. The airflow exiting from the outlet 202 exhibits excessive circumferential swirling speed, preventing smooth outward flow. When H2 > 65mm, although the stationary guide vane 204 effectively rectifies the rotating airflow discharged from the oblique flow impeller 10, it leads to an excessively large overall size of the power system 100. Therefore, when 35mm ≤ H2 ≤ 65mm, the rotating airflow discharged from the oblique flow impeller 10 is effectively rectified without causing an excessively large overall size of the power system 100.

[0064] Please see Figure 7 and Figure 9 In some embodiments, the trailing edge 22 has a second inner end point 221 close to the hub 1 and a second outer end point 222 away from the hub 1. The midpoint connecting the second inner end point 221 and the second outer end point 222 is the first center point 223. The distance between the first center point 223 and the stationary guide vane 204 along the extension direction of the central axis N is H3, and H3 satisfies: 10mm≤H3≤35mm.

[0065] Optionally, there is a certain gap between the trailing edge 22 of the main blade 2 and the stationary guide vane 204 to prevent the impeller 10 from colliding with the stationary guide vane 204 when it rotates. The first center point 223 between the second inner end point 221 and the second outer end point 222 is the midpoint on the trailing edge 22 of the main blade 2, and the distance between the first center point 223 and the leading edge 21 of the stationary guide vane 204 is H3.

[0066] When H3 < 10 mm, the gap between the main blade 2 and the stationary guide vane 204 is too small, which will cause the high-speed airflow leaving the main blade 2 to impact the leading edge 21 of the stationary guide vane 204, resulting in excessive aerodynamic noise. When H3 > 35 mm, the gap between the main blade 2 and the stationary guide vane 204 is too large, which will cause the stationary guide vane 204 to have a poorer effect in rectifying the rotating airflow discharged from the diagonal flow impeller 10. Therefore, when 10 mm ≤ H3 ≤ 35 mm, it can ensure that the stationary guide vane 204 has a good rectification effect and prevent the airflow from impacting the leading edge 21 of the stationary guide vane 204.

[0067] Please see Figures 7 to 9 In some embodiments, the trailing edge 22 has a second inner end point 221 near the hub 1 and a second outer end point 222 away from the hub 1. The distance between the second inner end point 221 and the central axis N is R3 in a direction perpendicular to the central axis N. The gap between the oblique flow impeller 10 and the housing 20 is W. W and R3 satisfy: 1.5mm≤W≤0.15R3.

[0068] It should be noted that the diagonal flow impeller 10 needs to rotate relative to the casing 20, while the casing 20 is stationary. Therefore, a certain gap needs to be maintained between the diagonal flow impeller 10 and the casing 20. The smaller the gap W between the diagonal flow impeller 10 and the casing 20, the better the performance of the power system 100. Thus, when W≤0.15R3, the power system 100 can have better performance. However, when W<1.5mm, it will be difficult to assemble the diagonal flow impeller 10 into the casing 20, and the diagonal flow impeller 10 will also easily rub against the casing 20. Therefore, W and R3 satisfy: 1.5mm≤W≤0.15R3.

[0069] Please see Figure 2 , Figure 7 and Figure 8 In some embodiments, the housing 20 has an air outlet 202 communicating with the receiving cavity 201, and the housing 20 includes a first annular wall 205 and a second annular wall 206 arranged around the central axis N, with the air outlet 202 formed between the first annular wall 205 and the second annular wall 206, and the first annular wall 205 located inside the second annular wall 206; wherein, the trailing edge 22 has a second inner end point 221 near the hub 1 and a second outer end point 222 away from the hub 1, and along a direction perpendicular to the central axis N, the distance between the second inner end point 221 and the central axis N is R3, the distance between the second outer end point 222 and the central axis N is R4, the distance between the first annular wall 205 and the central axis N is R5, and the distance between the second annular wall 206 and the central axis N is R6, and R3, R4, R5 and R6 satisfy: R3≤R5≤1.35R3, R4≤R6≤1.3R4.

[0070] Optionally, the air outlet end of the housing 20 has a first annular wall 205 and a second annular wall 206. The first annular wall 205 and the second annular wall 206 are both arranged around the central axis N, and the first annular wall 205 is located inside the second annular wall 206. An annular air outlet 202 is formed between the first annular wall 205 and the second annular wall 206. Multiple stationary guide vanes 204 are arranged between the first annular wall 205 and the second annular wall 206.

[0071] It is understandable that the distance R6 between the second annular wall 206 and the central axis N is the outer diameter of the annular air outlet 202, and the distance R4 between the second outer end point 222 and the central axis N is the maximum distance between the trailing edge 22 of the main blade 2 and the central axis N. Since the airflow does not flow completely axially as it leaves the trailing edge 22 of the main blade 2 and flows towards the air outlet 202, the airflow also carries a circumferential swirling speed. Thus, when R4≤R6, the airflow leaving the main blade 2 can flow more smoothly towards the air outlet 202, preventing the airflow leaving the main blade 2 from deflecting at a large angle and reducing airflow resistance. In addition, when R6>1.3R4, it will cause the overall structural size of the power system 100 to be too large. Therefore, R6 satisfies: R4≤R6≤1.3R4.

[0072] It can also be understood that the distance R5 between the first annular wall 205 and the central axis N is the inner diameter of the annular air outlet 202, and the distance R3 between the second inner end point 221 and the central axis N is the minimum distance between the trailing edge 22 of the main blade 2 and the central axis N. Similarly, since the airflow leaving the trailing edge 22 of the main blade 2 also has a circumferential swirling speed, when R3≤R5, the airflow leaving the main blade 2 can flow more smoothly to the air outlet 202, preventing the airflow leaving the main blade 2 from deflecting too much and reducing airflow resistance. In order to prevent the overall structural size of the power system 100 from being too large, it is also necessary to ensure that R5≤1.35R3. Thus, R3≤R5≤1.35R3.

[0073] Thirdly, please refer to Figure 11 This application provides a bladeless fan 1000, which includes a base 200, the aforementioned power system 100, and a duct shell 300. The base 200 is provided with a filter structure 2001. The power system 100 is installed on the base 200, and the air inlet 203 of the power system 100 is connected to the filter structure 2001. The duct shell 300 has an air outlet duct 301, which is installed on the power system 100 and is connected to the air outlet 202.

[0074] Optionally, the power system 100 is installed above the base 200, the air duct shell 300 is installed above the power system 100, and the air inlet 203 of the power system 100 is connected to the filter structure 2001, and the air outlet 202 of the power system 100 is connected to the air outlet duct 301. When the power system 100 is working, the power system 100 can drive the external air into the filter structure 2001. The air purified by the filter structure 2001 flows into the power system 100, and then flows into the air outlet duct 301 through the air outlet 202. Finally, it is blown to the user through the air outlet duct 301, so that the bladeless fan 1000 can provide the user with a clean and comfortable air supply experience.

[0075] Furthermore, the beneficial effects of the bladeless fan 1000 in this application are the same as those of the power system 100 in this application, and will not be repeated here.

[0076] Please see Figure 12 and Figure 13 In some embodiments, the air outlet duct 301 extends along the extension direction of the central axis N, and the air outlet duct 301 has a first connecting port 302 communicating with the air outlet 202 and a second connecting port 303 for blowing air outward. The air outlet direction of the second connecting port 303 is set at an angle to the extension direction of the central axis N, and the flow area of ​​the air outlet duct 301 gradually decreases in the direction away from the first connecting port 302.

[0077] Optionally, the duct housing 300 is a housing extending upward from the air outlet 202 of the power system 100. The bottom end of the duct housing 300 has a first connecting port 302 that communicates with the air outlet duct 301. The first connecting port 302 is connected to the air outlet 202 of the power system 100. When the power system 100 is working, the airflow discharged by the power system 100 flows into the air outlet duct 301 from the first connecting port 302. Figure 12 The arrows indicate the direction of airflow. The air outlet duct 301 extends along the extension direction of the central axis N, and the circumferential side of the duct shell 300 has a second connecting port 303 that communicates with the air outlet duct 301. The opening direction of the second connecting port 303 is perpendicular to the extension direction of the central axis N, so that when the airflow blows out from the second connecting port 303, the air outlet direction of the second connecting port 303 is perpendicular to the extension direction of the central axis N, which makes it convenient for the bladeless fan 1000 to blow air to the user.

[0078] It should be noted that the main function of the air outlet duct 301 is to rectify the airflow discharged from the power system 100, thereby changing the airflow direction and converting the axial flow into radial flow. It also concentrates the airflow to increase its velocity, thus achieving a high wind speed. However, because the initial momentum of the airflow discharged from the power system 100 is large, more airflow will concentrate at the top of the air outlet duct 301, resulting in uneven airflow from the second connecting port 303.

[0079] In this embodiment, the flow area of ​​the air outlet duct 301 gradually decreases along the direction away from the first connecting port 302, resulting in greater airflow resistance at positions further away from the first connecting port 302 within the air outlet duct 301. This forces more airflow out from the bottom of the air outlet duct 301, allowing for more uniform airflow from the second connecting port 303 and improving the comfort of the air supply. In some embodiments, the flow area at the top of the air outlet duct 301 is S1, and the flow area at the bottom of the air outlet duct 301 is S2, where S1 ≤ 0.5S2.

[0080] Please see Figure 13 In some embodiments, the second connection port 303 includes a plurality of sub-ports 3031, which are arranged sequentially along the extension direction of the central axis N; wherein, the height of the sub-ports 3031 along the extension direction of the central axis N is H4, and the height H4 of the plurality of sub-ports 3031 decreases sequentially along the direction away from the first connection port 302.

[0081] Optionally, the second connecting port 303 is a square opening, and multiple spacer ribs are provided inside the second connecting port 303. The multiple spacer ribs are arranged sequentially at intervals along the extension direction of the central axis N, and the multiple spacer ribs divide the second connecting port 303 into multiple sub-ports 3031. A sub-port 3031 is formed between two adjacent spacer ribs. The height of the sub-port 3031 along the extension direction of the central axis N is H4. And along the direction away from the first connecting port 302, the height H4 of the multiple sub-ports 3031 decreases sequentially, that is, the flow area of ​​the multiple sub-ports 3031 decreases sequentially. Similarly, the airflow resistance in the air outlet duct 301 is greater the further away from the first connecting port 302, thereby making the air outlet duct 301 have a better rectification effect.

[0082] Please see Figure 14 In some embodiments, the air duct housing 300 has a plurality of perforations 304, all of which are connected to the air outlet duct 301 and penetrate the outer surface of the air duct housing 300. The diameter of the perforations 304 is D, and D satisfies: 3mm≤D≤10mm.

[0083] Optionally, the duct housing 300 is made of perforated 304 plate, so that the outer surface of the duct housing 300 has multiple perforations 304, which are connected to the air outlet duct 301. The axial direction of the perforations 304 is set at an angle to the extension direction of the central axis N. When the airflow flows in the air outlet duct 301, since the airflow direction is set at an angle to the axial direction of the perforations 304, the airflow will basically not flow into the perforations 304. The airflow will flow along the air outlet duct 301. However, the sound propagation is non-directional, and the sound will enter the perforations 304, thereby reducing airflow noise.

[0084] It should be noted that when D < 3mm, the aperture of the perforation 304 is too small, which prevents sound from being transmitted well into the perforation 304, resulting in poor noise reduction. When D > 10mm, the aperture of the perforation 304 is too large. Although the noise reduction effect is improved, more airflow will enter the perforation 304, affecting the air outlet effect of the air duct 301 and weakening the overall structural strength of the duct shell 300. Therefore, when 3mm ≤ D ≤ 10mm, airflow noise can be reduced without significantly affecting the air outlet effect of the air duct 301.

[0085] Please see Figure 14 and Figure 15 In some embodiments, the bladeless fan 1000 further includes a sound-absorbing element 400 disposed on the outer surface of the duct housing 300 and covering a plurality of perforations 304.

[0086] Optionally, the sound-absorbing component 400 is typically made of porous sound-absorbing material, such as polyurethane sound-absorbing cotton, fiberglass cotton, non-woven fabric, felt, or open-pore sponge. By placing the sound-absorbing component 400 on the outer surface of the air duct shell 300 and covering multiple perforations 304, the airflow resistance of the perforations 304 can be increased, preventing airflow in the air outlet duct 301 from flowing into the perforations 304. The sound-absorbing component 400 itself can absorb noise in the air outlet duct 301, further reducing the operating noise of the bladeless fan 1000.

[0087] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," and "right" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing this application 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, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting this patent. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0088] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A diagonal flow impeller, characterized in that, include: A wheel hub has a central axis; Multiple main blades are disposed on the hub, and the multiple main blades are arranged around the central axis. Each main blade includes a leading edge and a trailing edge. The projection of the leading edge onto the first plane forms an angle with the projection of the trailing edge onto the first plane, the angle being α1, where α1 satisfies: 60°≤α1≤90°, and the first plane is perpendicular to the central axis.

2. The oblique flow impeller according to claim 1, characterized in that, The leading edge has a first inner end point near the hub and a first outer end point away from the hub, the trailing edge has a second inner end point near the hub and a second outer end point away from the hub, and the main blade also includes a first profile near the hub and a second profile away from the hub, the first inner end point and the second inner end point are located on the first profile, and the first outer end point and the second outer end point are located on the second profile. Wherein, the angle between the tangent of the first profile at the first inner endpoint and the first plane is β1, and β1 satisfies: 70°≤β1≤80°; The angle between the tangent of the first profile at the second inner endpoint and the first plane is β2, and β2 satisfies: 80°≤β2≤90°; The angle between the tangent of the second shape at the first outer endpoint and the first plane is β3, where β3 satisfies: 70°≤β3≤80°; The angle between the tangent of the second profile at the second outer endpoint and the first plane is β4, and β4 satisfies: 30°≤β4≤40°.

3. The oblique flow impeller according to claim 2, characterized in that, The line connecting the first inner endpoint and the first outer endpoint is the leading edge line, and the length of the leading edge line is L1. The line connecting the second inner endpoint and the second outer endpoint is the trailing edge line, and the length of the trailing edge line is L2. L1 and L2 satisfy: 0.5L1≤L2≤L1.

4. The oblique flow impeller according to claim 3, characterized in that, The angle formed by the leading edge line and the central axis is A1, and the angle formed by the trailing edge line and the central axis is A2. A1 and A2 satisfy: 80°≤A1≤100°, 35°≤A2≤60°.

5. The oblique flow impeller according to claim 2, characterized in that, Along a direction perpendicular to the central axis, the distance between the first inner endpoint and the central axis is R1, the distance between the first outer endpoint and the central axis is R2, the distance between the second inner endpoint and the central axis is R3, and the distance between the second outer endpoint and the central axis is R4. Among them, R1, R2, R3 and R4 satisfy: 0.1R3≤R1≤0.35R3, 0.65R4≤R2≤0.85R4, 0.55R4≤R3≤0.8R4.

6. The oblique flow impeller according to claim 5, characterized in that, The height of the main blade along the central axis is H1, and the ratio of H1 to R4 satisfies: 0.4≤H1 / R4≤1.

7. The oblique flow impeller according to claim 1, characterized in that, The oblique flow impeller also includes multiple flow-dividing blades, all of which are disposed on the hub and arranged around the central axis, with one flow-dividing blade located between two adjacent main blades.

8. The oblique flow impeller according to claim 7, characterized in that, At least one of the trailing edge of the main blade and the trailing edge of the diverter blade is provided with a plurality of trailing edge serrations; The plurality of trailing edge serrations are arranged sequentially in a direction away from the wheel hub, and the height of the trailing edge serrations is greater than or equal to the width of the trailing edge serrations.

9. A power system, characterized in that, include: The casing has a receiving cavity; The oblique flow impeller as described in any one of claims 1-8, wherein the oblique flow impeller is disposed within the receiving cavity; A drive unit is mounted on the housing, and the output shaft of the drive unit is driven to drive the diagonal flow impeller. The drive unit is used to drive the diagonal flow impeller to rotate around the central axis.

10. The power system according to claim 9, characterized in that, The housing has an air outlet, and the air outlet is provided with multiple stationary guide vanes, which are arranged at intervals around the central axis. Wherein, along the extension direction of the central axis, the height of the stationary guide vane is H2, and H2 satisfies: 35mm≤H2≤65mm.

11. The power system according to claim 10, characterized in that, The trailing edge has a second inner end point close to the hub and a second outer end point away from the hub, and the midpoint of the line connecting the second inner end point and the second outer end point is the first center point; Wherein, along the extension direction of the central axis, the distance between the first center point and the stationary guide vane is H3, and H3 satisfies: 10mm≤H3≤35mm.

12. The power system according to claim 9, characterized in that, The trailing edge has a second inner end point near the hub and a second outer end point away from the hub. In a direction perpendicular to the central axis, the distance between the second inner end point and the central axis is R3. The gap between the oblique flow impeller and the housing is W. W and R3 satisfy: 1.5mm≤W≤0.15R3.

13. The power system according to claim 9, characterized in that, The housing has an air outlet communicating with the receiving cavity, and the housing includes a first annular wall and a second annular wall arranged around the central axis, the air outlet being formed between the first annular wall and the second annular wall, and the first annular wall being located inside the second annular wall; The trailing edge has a second inner end point near the hub and a second outer end point away from the hub. In a direction perpendicular to the central axis, the distance between the second inner end point and the central axis is R3, the distance between the second outer end point and the central axis is R4, the distance between the first annular wall and the central axis is R5, and the distance between the second annular wall and the central axis is R6. R3, R4, R5, and R6 satisfy: R3≤R5≤1.35R3, R4≤R6≤1.3R4.

14. A bladeless fan, characterized in that, include: The base is equipped with a filter structure; The power system as described in any one of claims 9 to 13, the power system having an air inlet and an air outlet, the power system being mounted on the base, and the air inlet being in communication with the filter structure; The air duct housing has an air outlet duct, the air duct housing is installed in the power system, and the air outlet duct is connected to the air outlet.

15. The bladeless fan according to claim 14, characterized in that, The air outlet duct extends along the extension direction of the central axis, and the air outlet duct has a first connecting port that communicates with the air outlet and a second connecting port for blowing air outward. The air outlet direction of the second connecting port is set at an angle to the extension direction of the central axis, and the flow area of ​​the air outlet duct gradually decreases in the direction away from the first connecting port.

16. The bladeless fan according to claim 15, characterized in that, The second communication port includes multiple sub-ports, which are arranged sequentially along the extension direction of the central axis; The height of the sub-port along the central axis is H4, and the height H4 of the multiple sub-ports decreases sequentially in the direction away from the first connecting port.

17. The bladeless fan according to claim 14, characterized in that, The duct shell has multiple perforations, all of which are connected to the air outlet duct and penetrate the outer surface of the duct shell. The diameter of the perforations is D, which satisfies the condition: 3mm≤D≤10mm.

18. The bladeless fan according to claim 17, characterized in that, The bladeless fan also includes a sound-absorbing component, which is disposed on the outer surface of the air duct shell and covers the plurality of perforations.

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