Centrifugal fan wheel, centrifugal fan and air conditioning device

Abstract

The utility model discloses a centrifugal fan wheel, centrifugal fan and air conditioning equipment, centrifugal fan wheel includes a plurality of interval arrangement blade along the circumference, and the adjacent two blade between define airflow passage, airflow passage has first wall surface and second wall surface relatively and interval arrangement along the circumference, on the cross section of centrifugal fan wheel, the first wall surface and second wall surface of airflow passage have a plurality of first common tangent circle of tangency first wall surface and second wall surface, in the radial direction of centrifugal fan wheel, the both ends of airflow passage are respectively inner end and outer end, and the radius of a plurality of first common tangent circle increases first and then decreases along the direction of inner end to outer end. The width of airflow passage increases first and then decreases along the direction of inner end to outer end, can reduce airflow flow velocity at inner end, is favorable to airflow steady flow and flows into airflow passage, reduces turbulence, reduces airflow loss, and can reduce vortex noise, and after airflow steady flow, the width of airflow passage gradually reduces, and airflow flow velocity increases, can promote aerodynamic efficiency.

Description

Technical Field

[0001] This utility model relates to the field of air conditioning equipment technology, and in particular to a centrifugal impeller, a centrifugal fan and an air conditioning device. Background Technology

[0002] In related technologies, the impeller of a centrifugal fan is sensitive to the incoming flow. The flow loss of the airflow in the airflow channel defined between two adjacent blades of the centrifugal fan is large, which can easily generate vortex noise and reduce aerodynamic efficiency, leaving room for improvement. Utility Model Content

[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 centrifugal impeller that can reduce airflow loss, lower eddy noise, and improve aerodynamic efficiency.

[0004] This utility model also proposes a centrifugal fan having the above-mentioned centrifugal impeller.

[0005] This utility model further proposes an air conditioning device having the aforementioned centrifugal fan.

[0006] According to a first aspect of the present invention, a centrifugal impeller includes: a plurality of blades, the plurality of blades being arranged circumferentially at intervals, and an airflow channel being defined between two adjacent blades; the airflow channel having a first wall and a second wall arranged circumferentially opposite and at intervals; in the cross-section of the centrifugal impeller, a plurality of first common tangent circles are formed between the first wall and the second wall of the airflow channel, each of the first common tangent circles being tangent to the first wall and the second wall of the airflow channel; in the radial direction of the centrifugal impeller, the two ends of the airflow channel are an inner end and an outer end, respectively; the radius of the plurality of first common tangent circles first increases and then decreases along the direction from the inner end to the outer end.

[0007] According to the centrifugal impeller of this utility model embodiment, by designing the width of the airflow channel to first increase and then decrease along the direction from the inner end to the outer end, the flow area entering the airflow channel is first increased, thereby reducing the airflow velocity at the inner end. This can increase the fault tolerance rate of the turbulence at the inner end of the airflow channel, which is conducive to the stable flow of air into the airflow channel, reducing turbulence, reducing airflow loss, and reducing eddy noise. After the airflow enters the airflow channel and flows stably, the width of the airflow channel gradually decreases, the airflow velocity increases and it is discharged from the outer end, which can improve aerodynamic efficiency.

[0008] In some embodiments, in the radial direction of the centrifugal impeller, the thickness of the blade first increases and then decreases along the direction from the inner end to the outer end.

[0009] In some embodiments, the thickness of the blade has two side walls, which are respectively the first wall of one of the airflow channels and the second wall of the other airflow channel. On the cross-section of the centrifugal impeller, there are multiple second common tangent circles between the first wall and the second wall of the blade, each of the second common tangent circles being tangent to the first wall and the second wall of the blade. In the radial direction of the centrifugal impeller, the radii of the multiple second common tangent circles first increase and then decrease along the direction from the inner end to the outer end.

[0010] In some embodiments, the blade has a centerline in its thickness direction, and the centers of a plurality of second common tangent circles are all located on the centerline. The centerline is divided into a first segment corresponding to the inner end and a second segment corresponding to the outer end by the center of the largest of the plurality of second common tangent circles. The ratio of the length of the first segment to the length of the second segment is x, where 0.3 ≤ x ≤ 0.6.

[0011] In some embodiments, the maximum diameter of the plurality of second common tangent circles is Dmax, the minimum diameter is Dmin, the second common tangent circle with diameter Dmin corresponds to the outer end, and 0.3≤Dmin / Dmax≤0.6.

[0012] In some embodiments, the thickness of the blade is divided into a first side and a second side, the first wall surface is disposed corresponding to the first side, the second wall surface is disposed corresponding to the second side, and both the first wall surface and the second wall surface are convex toward the second side. The position on the first wall surface corresponding to the largest radius of the first common tangent circle is disposed adjacent to the inner end.

[0013] In some embodiments, the blade has a centerline in its thickness direction, and the angle between the tangents at both ends of the centerline toward the blade is α, where 94°≤α≤110°.

[0014] A centrifugal fan according to a second aspect of the present invention includes a volute and a centrifugal impeller according to a first aspect of the present invention, wherein the centrifugal impeller is rotatably disposed within the volute.

[0015] According to the centrifugal fan of the present invention, by setting the centrifugal impeller of the first aspect of the present invention, airflow noise can be reduced and airflow conveying efficiency can be improved.

[0016] In some embodiments, the volute has air inlets at both axial ends, and a diffuser section is provided inside the volute. The diffuser section is connected to the air outlet side of the centrifugal impeller and includes a first diffuser wall and a second diffuser wall disposed opposite to each other. One end of the first diffuser wall is connected to the volute tongue of the volute, and the other end extends to the air outlet of the volute. At least the middle region of the volute tongue and the first diffuser wall in the axial direction protrudes away from the second diffuser wall.

[0017] In some embodiments, the radial distance between the volute tongue and the centrifugal impeller remains constant along the axial direction.

[0018] In some embodiments, the centrifugal impeller includes an impeller body and a plurality of reinforcing frames spaced apart along the axial direction. The impeller body includes at least one set of blades, each set of blades including a plurality of blades spaced apart along the circumferential direction. The outer circumferential contour of the impeller body does not exceed the outer circumferential contour of the blades. The reinforcing frames protrude outward from the outer circumferential contour of the impeller body. The volute has a volute section inside, and the centrifugal impeller is disposed in the volute section. The circumferential wall of the volute section forms a recessed groove that is recessed outward along the radial direction. The groove wall extends circumferentially to connect with the volute tongue of the volute, and the groove corresponds to the reinforcing frames.

[0019] In some embodiments, the reinforcing frame consists of two parts, located at opposite ends of the centrifugal impeller.

[0020] In some embodiments, the volute has air inlets at both axial ends, and a diffuser section is provided inside the volute. The diffuser section is connected to the air outlet side of the centrifugal impeller and includes a first diffuser wall and a second diffuser wall disposed opposite to each other. One end of the first diffuser wall is connected to the volute tongue of the volute, and the other end extends to the air outlet of the volute. The volute tongue includes a first wall portion and a second wall portion. The first wall portion spans across opposite sides of the axial center plane of the volute, and the distance between the first wall portion and the second diffuser wall first increases and then decreases along the axial direction. The distance between the second wall portion and the second diffuser wall is along the axial direction. The first wall portion is connected to the second wall portion at both axial ends. The first diffuser wall includes a third wall portion and a fourth wall portion. The third wall portion spans across the opposite sides of the central plane of the volute in the axial direction. The distance between the third wall portion and the second diffuser wall increases and then decreases along the axial direction. The distance between the fourth wall portion and the second diffuser wall remains unchanged along the axial direction. The first wall portion is connected to the third wall portion and is axially offset from the settling tank. The second wall portion is connected between the tank wall of the settling tank and the fourth wall portion.

[0021] In some embodiments, the volute is provided with a flow collecting ring at the air inlet, and the flow collecting ring has a flow guiding channel. The flow guiding channel has an air inlet end and an air outlet end that are spaced apart along the axial direction. The flow guiding channel includes a first flow channel section and a second flow channel section. The end of the first flow channel section away from the second flow channel section defines the air inlet end, and the end of the second flow channel section away from the first flow channel section defines the air outlet end. The flow area of ​​the first flow channel section decreases along the direction from the air inlet end to the air outlet end, and the flow area of ​​the second flow channel section increases along the direction from the air inlet end to the air outlet end.

[0022] In some embodiments, the outer peripheral wall of the flow collecting ring includes a first flow collecting wall and a second flow collecting wall that are axially connected. The first flow collecting wall is disposed corresponding to the first flow channel segment, and the second flow collecting wall is disposed corresponding to the second flow channel segment. In the longitudinal section of the flow collecting ring, the first flow collecting wall extends as an arc and the second flow collecting wall extends as a straight line. The inner peripheral wall of the flow collecting ring includes a third flow collecting wall and a fourth flow collecting wall that are axially connected. The third flow collecting wall is disposed corresponding to the first flow channel segment, and the fourth flow collecting wall is disposed corresponding to the second flow channel segment. In the longitudinal section of the flow collecting ring, the third flow collecting wall extends as an arc and the fourth flow collecting wall extends as a curve and extends close to the second flow collecting wall in the direction toward the air outlet end; and / or, the flow guide channel is provided with a sound-absorbing sawtooth structure at the air outlet end.

[0023] In some embodiments, the volute has a diffuser section connected to the air outlet side of the centrifugal impeller, and includes a third diffuser wall and a fourth diffuser wall disposed opposite to each other. The third diffuser wall and the fourth diffuser wall are respectively connected to the two ends of the volute tongue of the volute, and both extend away from each other in the direction toward the air outlet of the volute.

[0024] An air conditioning device according to a third aspect of the present invention includes a centrifugal fan according to a second aspect of the present invention.

[0025] According to the embodiments of the present invention, by setting the centrifugal fan described in the second aspect, the overall performance of the air conditioning equipment is improved, which is conducive to increasing the air supply volume of the air conditioning equipment and reducing the operating noise of the air conditioning equipment.

[0026] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the structure of a centrifugal impeller according to some embodiments of the present invention; Figure 2This is a cross-sectional view of the centrifugal impeller according to some embodiments of the present invention; Figure 3 This is a schematic diagram of the flow channel between two adjacent blades according to some embodiments of the present invention; Figure 4 This is an axial cross-sectional view of the blades of a centrifugal impeller according to some embodiments of the present invention; Figure 5 This is an axial cross-sectional view of two adjacent blades according to some embodiments of the present invention; Figure 6 This is a schematic diagram of the airflow deflection angle of the blades of a centrifugal impeller according to some embodiments of the present invention; Figure 7 This is a structural schematic diagram of a centrifugal fan according to some embodiments of the present invention; Figure 8 This is an axial cross-sectional view of the volute of a centrifugal fan according to some embodiments of the present invention; Figure 9 This is a front view of a centrifugal fan according to some embodiments of the present invention; Figure 10 This is a cross-sectional view of the volute of a centrifugal fan according to some embodiments of the present invention; Figure 11 This is another cross-sectional view of the volute of a centrifugal fan according to some embodiments of the present invention; Figure 12 This is a cross-sectional view of the volute of a centrifugal fan according to some embodiments of the present invention.

[0028] Figure label: Centrifugal fan 1000; Centrifugal impeller 100; impeller body 100a; blade assembly 10; Blade 1; Centerline 11; First segment 111; Second segment 112; First tangent 113; Second tangent 114; First side 12; Second side 13; Airflow channel 2; First wall 21; Second wall 22; Inner end 23; Outer end 24; First common tangent circle 3; First circle 31; Second circle 32; Third circle 33; Second common tangent circle 4; Fourth circle 41; Fifth circle 42; Sixth circle 43; 100b reinforced border; 200 volute; 201 air inlet; 202 air outlet; center surface M; 200a spiral section; 55mm settling tank; Diffusion section 200b; First diffusion wall 51; Third wall portion 511; Fourth wall portion 512; Second diffusion wall 52; Third diffusion wall 53; Fourth diffusion wall 54; 6. Cochlear tongue; 61. First wall portion; 62. Flow collector ring 7; flow guide channel 71; air inlet end 711; air outlet end 712; first flow channel section 713; second flow channel section 714; noise-absorbing sawtooth structure 715; first flow collector wall 72; second flow collector wall 73. Detailed Implementation

[0029] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0030] The following disclosure provides numerous different embodiments or examples for implementing various structures of the present invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of the invention. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0031] The centrifugal impeller 100 of the first aspect of this utility model is described below with reference to the accompanying drawings.

[0032] According to the centrifugal impeller 100 of this utility model embodiment, such as Figures 1-3 As shown, the centrifugal impeller 100 includes: a plurality of blades 1, which are spaced apart circumferentially, and an airflow channel 2 is defined between two adjacent blades 1. The airflow channel 2 has a first wall 21 and a second wall 22 that are circumferentially opposite and spaced apart. On the cross-section of the centrifugal impeller 100, there are a plurality of first common tangent circles 3 between the first wall 21 and the second wall 22 of the airflow channel 2. Each first common tangent circle 3 is tangent to the first wall 21 and the second wall 22 of the airflow channel 2. In the radial direction of the centrifugal impeller 100, the two ends of the airflow channel 2 are an inner end 23 and an outer end 24, respectively. The radius of the plurality of first common tangent circles 3 first increases and then decreases along the direction from the inner end 23 to the outer end 24.

[0033] The centrifugal impeller 100 includes multiple blades 1, which are spaced apart circumferentially along the centrifugal impeller 100. When the centrifugal impeller 100 rotates, airflow enters along the axial direction of the centrifugal impeller 100 and exits along the radial direction of the centrifugal impeller 100. When the airflow passes through the blades 1, the airflow flows into the airflow channel 2 defined between two adjacent blades 1. The two ends of the airflow channel 2 are the inner end 23 and the outer end 24, respectively. The leading edge of the blade 1 defines the inner end 23 of the airflow channel 2, and the trailing edge of the blade 1 defines the outer end 24 of the airflow channel 2. The airflow flows from the leading edge of the blade 1 to the trailing edge of the blade 1. Therefore, when the airflow flows in the airflow channel 2, it flows from the inner end 23 to the outer end 24.

[0034] In related technologies, the airflow loss within the airflow channel defined between two adjacent blades of a centrifugal impeller is large, which easily generates vortex noise and reduces aerodynamic efficiency, leaving room for improvement.

[0035] The centrifugal impeller 100 of this embodiment improves the airflow channel 2 between two adjacent blades 1. The airflow channel 2 has a first wall 21 and a second wall 22 that are circumferentially opposite and spaced apart. The first wall 21 and the second wall 22 are respectively constructed on the two circumferentially opposite sides of the two adjacent blades 1. The diameter of the first common tangent circle 3 that is tangent to both the first wall 21 and the second wall 22 can be expressed as the width of the airflow channel 2. There are multiple first common tangent circles 3 between the first wall 21 and the second wall 22. In the direction from the inner end 23 to the outer end 24, the diameter of the first common tangent circle 3 first increases and then decreases. That is, in the direction of airflow, the width of the airflow channel 2 first increases and then decreases.

[0036] It is worth noting that there are multiple first common tangent circles 3 between the first wall 21 and the second wall 22 of the airflow channel 2. This means that the first common tangent circle 3 is the circle that is tangent to both the first wall 21 and the second wall 22 in the same airflow channel 2. The common tangent circles of the first wall 21 and the second wall 22 of different airflow channels 2 do not belong to the first common tangent circle 3.

[0037] like Figure 3 As shown, the first common tangent circle 3 includes a first circle 31, a second circle 32, and a third circle 33 arranged sequentially from the inner end 23 to the outer end 24. The diameter of the first circle 31 is... 1 is less than the diameter of the second circle 32. 2. The diameter of the third circle 33 3 is less than the diameter of the second circle 32. 2. That is, the width of the airflow channel 2 increases first and then decreases along the direction from the inner end 23 to the outer end 24.

[0038] By designing the width of the airflow channel 2 to first increase and then decrease along the direction from the inner end 23 to the outer end 24, the airflow entering the airflow channel 2 decelerates and then accelerates. Increasing the flow area entering the airflow channel 2 first, thereby reducing the airflow velocity at the inner end 23, increases the turbulence tolerance of the inner end 23 of the airflow channel 2, which is beneficial for the stable flow of airflow into the airflow channel 2, reduces turbulence, reduces airflow losses, and also reduces eddy noise. After the airflow enters the airflow channel 2 and flows stably, the flow area of ​​the airflow channel 2 gradually decreases and the airflow velocity increases, which can improve aerodynamic efficiency.

[0039] According to the centrifugal impeller 100 of this utility model embodiment, by designing the width of the airflow channel 2 to first increase and then decrease along the direction from the inner end 23 to the outer end 24, the flow area entering the airflow channel 2 is first increased, thereby reducing the airflow velocity at the inner end 23. This can increase the fault tolerance rate of the turbulence at the inner end 23 of the airflow channel 2, which is conducive to the stable flow of air into the airflow channel 2, reducing turbulence, reducing airflow loss, and reducing eddy noise. After the airflow enters the airflow channel 2 and flows stably, the width of the airflow channel 2 gradually decreases, the airflow velocity increases and it is discharged from the outer end 24, which can improve aerodynamic efficiency.

[0040] In some embodiments of this utility model, such as Figure 4 As shown, in the radial direction of the centrifugal impeller 100, the thickness of the blade 1 first increases and then decreases along the direction from the inner end 23 to the outer end 24.

[0041] The airflow moves from the inner end 23 to the outer end 24 within the airflow channel 2. By designing the thickness of the blade 1 to first increase and then decrease along the direction from the inner end 23 to the outer end 24, the thickness of the blade 1 near the inner end 23 is smaller. This increases the width of the inner end 23 of the airflow channel 2, which is beneficial for increasing the intake volume. Furthermore, the relatively thin leading edge of the blade 1 reduces airflow separation and inlet impact losses, further increasing the intake volume and reducing airflow losses. Reducing the thickness of the blade 1 near the leading edge also reduces the moment of inertia, which helps to lower manufacturing costs.

[0042] The blade 1 is thicker in the middle part from the inner end 23 to the outer end 24, which can improve the tensile stiffness of the blade 1, reduce the occurrence of deformation or breakage of the blade 1, and improve the working reliability of the blade 1.

[0043] The reduced thickness of blade 1 near the outer end 24 can reduce trailing edge vortex loss, improve the flow of airflow from the outer end 24, and reduce aerodynamic noise.

[0044] In addition, the thickness of blade 1 is designed to increase first and then decrease along the direction from the inner end 23 to the outer end 24. The change in thickness makes the centrifugal force evenly distributed along the span of blade 1, which can reduce the stress concentration near the outer end 24 of blade 1 and help extend the working life of blade 1.

[0045] In some embodiments of this utility model, such as Figure 4 As shown, the thickness of the blade 1 is such that the two side walls are the first wall 21 of one airflow channel 2 and the second wall 22 of the other airflow channel 2. On the cross-section of the centrifugal impeller 100, there are multiple second common tangent circles 4 between the first wall 21 and the second wall 22 of the blade 1. Each second common tangent circle 4 is tangent to the first wall 21 and the second wall 22 of the blade 1. In the radial direction of the centrifugal impeller 100, the radius of the multiple second common tangent circles 4 first increases and then decreases along the direction from the inner end 23 to the outer end 24.

[0046] The centrifugal impeller 100 has multiple blades 1 spaced apart circumferentially. An airflow channel 2 is defined between two adjacent blades 1, thus the same blade 1 simultaneously defines two circumferentially adjacent airflow channels 2. The thickness direction of the blade 1 is circumferential to the centrifugal impeller 100. One of the two side walls of the blade 1 is the first wall 21 of the airflow channel 2, and the other side wall is the second wall 22 of the airflow channel 2. The diameter of the second common tangent circle 4, which is tangent to both side walls of the same blade 1, represents the thickness dimension of the blade 1.

[0047] The thickness of the same blade 1 defines the first wall 21 and the second wall 22 of different airflow channels 2 on both sides. The diameter of the second common tangent circle 4 that is tangent to both sides of the thickness of the same blade 1 can be expressed as the thickness dimension of the blade 1. In other words, the diameter of the second common tangent circle 4 that is tangent to both the first wall 21 and the second wall 22 of the same blade 1 can be expressed as the thickness dimension of the blade 1.

[0048] Along the direction from the inner end 23 to the outer end 24, the radii of the plurality of second common tangent circles 4 first increase and then decrease, that is, the thickness of the blade 1 first increases and then decreases along the direction from the inner end 23 to the outer end 24.

[0049] like Figure 4 As shown, the second common tangent circle 4 includes a fourth circle 41, a fifth circle 42 and a sixth circle 43 arranged sequentially from the inner end 23 to the outer end 24. The diameter D1 of the fourth circle 41 is smaller than the diameter Dmax of the fifth circle 42, and the diameter Dmin of the sixth circle 43 is smaller than the diameter Dmax of the fifth circle 42. That is, the thickness of the blade 1 first increases and then decreases along the direction from the inner end 23 to the outer end 24.

[0050] In some embodiments of this utility model, such as Figure 4As shown, the blade 1 has a centerline 11 in its thickness direction. The centers of multiple second common tangent circles 4 are all located on the centerline 11. The center of the largest diameter of the multiple second common tangent circles 4 divides the centerline 11 into a first segment 111 corresponding to the inner end 23 and a second segment 112 corresponding to the outer end 24. The ratio of the length L1 of the first segment 111 to the length L2 of the second segment 112, L1 / L2, is x, where 0.3≤x≤0.6.

[0051] The center of the second common tangent circle 4, which has the largest diameter, represents the thickest point of blade 1. The length L1 of the first line segment 111 represents the length from the inner end 23 to the thickest point of blade 1, and the length L2 of the second line segment 112 represents the length from the outer end 24 to the thickest point of blade 1. Here, the length L1 of the first line segment 111 refers to the arc length along the extension direction of the first line segment 111, and the length L2 of the second line segment 112 refers to the arc length along the extension direction of the second line segment 112.

[0052] By designing the ratio x of the length L1 of the first segment 111 to the length L2 of the second segment 112 to be 0.3≤x≤0.6, the thickest part of the blade 1 is positioned closer to the inner end 23 relative to the middle of the centerline 11. This provides stronger structural support for the position of the blade 1 near the inner end 23. The outer end 24 of the blade 1 is fixedly connected, while the inner end 23 of the blade 1 is a free end, which improves the deformation resistance of the blade 1 near the inner end 23 and enhances the operational reliability of the blade 1.

[0053] Furthermore, the thickness of blade 1 increases first and then decreases along the direction from the inner end 23 to the outer end 24. The thickest part of blade 1 is located closer to the inner end 23 than the middle of the center line 11. Therefore, the thickness of blade 1 decreases from the thickest part of blade 1 to the longer part of the outer end 24. This can significantly reduce the thickness of blade 1 near the outer end 24, which is beneficial for reducing the trailing edge loss and airflow noise of blade 1.

[0054] Optionally, the ratio x of the length L1 of the first line segment 111 to the length L2 of the second line segment 112 can be 0.3, 0.4, 0.45, 0.5, 0.6, etc.

[0055] In some embodiments of this utility model, such as Figure 4 As shown, the maximum diameter of the multiple second common tangent circles 4 is Dmax, and the minimum diameter is Dmin. The second common tangent circle 4 with diameter Dmin corresponds to the outer end 24 and is set with 0.3≤Dmin / Dmax≤0.6.

[0056] like Figure 4As shown, the diameter of the second common tangent circle 4 closest to the outer end 24 is the smallest, with a diameter of Dmin. By designing the thickness of the blade 1 closest to the outer end 24 to be the smallest, the trailing edge loss and airflow noise of the blade 1 can be further reduced. Furthermore, it can reduce stress concentration near the outer end 24 of the blade 1, which is beneficial for improving the service life of the blade 1.

[0057] A ratio that is too large or too small between the diameters of the largest and smallest second common tangent circles 4 (Dmax and Dmin) is detrimental to the operation of blade 1. If the ratio is too large, the thickness of blade 1 near its outer end 24 is too small, or the thickness near its inner end 23 is too large, resulting in a weak structure near the outer end 24 and increasing the moment of inertia, thus reducing the operational stability of blade 1. If the ratio is too small, the thickness variation of blade 1 is not significant, leading to greater airflow loss and noticeable airflow noise.

[0058] Therefore, the optimal ratio of the diameter Dmax of the largest second common tangent circle 4 to the diameter Dmin of the smallest second common tangent circle 4, Dmin / Dmax, is 0.3 ≤ Dmin / Dmax ≤ 0.6. This reduces the wake loss near the outer end 24 of the blade 1 and lowers airflow noise. Furthermore, it improves the structural stability of the blade 1, reduces the moment of inertia, and enhances the operational stability of the blade 1.

[0059] Optionally, the ratio of the diameter Dmax of the largest second common tangent circle 4 to the diameter Dmin of the smallest second common tangent circle 4, Dmin / Dmax, can be 0.3, 0.4, 0.44, 0.45, 0.5, 0.6, etc.

[0060] In some embodiments of this utility model, such as Figure 5 As shown, the thickness of the blade 1 is divided into two sides: the first side 12 and the second side 13. The first wall surface 21 is set corresponding to the first side 12, and the second wall surface 22 is set corresponding to the second side 13. Both the first wall surface 21 and the second wall surface 22 protrude towards the second side 13. The first wall surface 21 is set near the inner end 23, which is located at the position with the largest radius corresponding to the first common tangent circle 3 on the first wall surface 21.

[0061] The centrifugal impeller 100 has multiple blades 1 spaced apart circumferentially. An airflow channel 2 is defined between two adjacent blades 1. Therefore, the same blade 1 simultaneously defines two circumferentially adjacent airflow channels 2. The thickness direction of the blade 1 is circumferential to the centrifugal impeller 100. The two sides of the thickness of the blade 1 are a first side 12 and a second side 13, respectively. The first side 12 defines a first wall 21 of one airflow channel 2, and the second side 13 defines a second wall 22 of another airflow channel 2. Both the first wall 21 and the second wall 22 protrude toward the second side 13.

[0062] The radii of the multiple first common tangent circles 3 increase first and then decrease along the direction from the inner end 23 to the outer end 24, and the radii of the multiple second common tangent circles 4 also increase first and then decrease along the direction from the inner end 23 to the outer end 24. The tangent point of the second common tangent circle 4 with the largest diameter on the first wall surface 21 of the same blade 1 is located closer to the inner end 23 than the tangent point of the first common tangent circle 3 with the largest diameter within the airflow channel 2 defined by the first wall surface 21 of this blade 1. In other words, the tangent point of the second common tangent circle 4 with the largest diameter is closer to the inner end 23 than the tangent point of the first common tangent circle 3 with the largest diameter.

[0063] The airflow channel 2 is positioned at its widest point, corresponding to the point where the thickness of the blade 1 gradually decreases. This facilitates the formation of an airflow channel 2 with a width that first increases and then decreases between two adjacent blades 1. This allows for a smoother change in the airflow arc, reduces stress concentration on the blade 1, and minimizes airflow loss.

[0064] In some embodiments of this utility model, such as Figure 6 As shown, the blade 1 has a centerline 11 in its thickness direction, and the angle between the tangents at both ends of the centerline 11 toward the blade 1 is α, 94°≤α≤110°.

[0065] like Figure 6 As shown, the tangent line closest to the inner end 23 of the centerline 11 is the first tangent line 113, and the tangent line closest to the outer end 24 of the centerline 11 is the second tangent line 114. The angle between the first tangent line and the second tangent line toward the blade 1 is α, and α satisfies: 94°≤α≤110°.

[0066] An angle α between the tangents at both ends of the centerline 11 and the blade 1, whether too large or too small, is detrimental to airflow guidance. If the angle α is too small, the risk of boundary layer separation increases, airflow loss increases, and vortices are easily generated. Conversely, if the angle α is too large, the blade 1 tends to extend in a straight line, weakening its airflow guidance effect.

[0067] Therefore, it is better to design the angle α between the tangents at both ends of the centerline 11 toward the blade 1 as 94°≤α≤110°, which can improve the airflow guiding effect, reduce airflow loss, and reduce the generation of vortices.

[0068] Optionally, the included angle α between the tangents at both ends of the centerline 11 toward the blade 1 can be 94°, 95°, 100°, 104°, 110°, etc.

[0069] Table 1 below is a data comparison chart of centrifugal impellers in related technologies and centrifugal impellers 100 in some embodiments of the present invention. The rotational speed of the centrifugal impeller in the related technologies is 920 rpm, while the rotational speed of the centrifugal impeller 100 in some embodiments of the present invention is 865 rpm. This can be regarded as a comparison under similar conditions.

[0070] Table 1

[0071] In some embodiments of this utility model, the centrifugal impeller 100 has a larger air volume and lower noise.

[0072] The centrifugal fan 1000 of the second aspect of the present invention is described below with reference to the accompanying drawings.

[0073] According to an embodiment of the present utility model, the centrifugal fan 1000, such as Figure 7 As shown, the centrifugal fan 1000 includes a volute 200 and a centrifugal impeller 100 according to the first aspect of the present invention, wherein the centrifugal impeller 100 is rotatably disposed within the volute 200. The volute 200 is the outline of the centrifugal fan 1000, and the centrifugal impeller 100 is disposed within the volute 200.

[0074] According to the centrifugal fan 1000 of the present invention, by setting the centrifugal impeller 100 of the first aspect, airflow noise can be reduced and airflow conveying efficiency can be improved.

[0075] In some embodiments of this utility model, such as Figure 7 and Figure 8 As shown, the volute 200 has air inlets 201 at both ends of its axial direction. The volute 200 has a diffuser section 200b inside, which is connected to the air outlet side of the centrifugal impeller 100 and includes a first diffuser wall 51 and a second diffuser wall 52 arranged opposite to each other. One end of the first diffuser wall 51 is connected to the volute tongue 6 of the volute 200, and the other end extends to the air outlet 202 of the volute 200. At least the middle region of the volute tongue 6 and the first diffuser wall 51 in the axial direction protrudes away from the second diffuser wall 52.

[0076] The volute 200 has air inlets 201 at both axial ends. The centrifugal fan 1000 drives the airflow to enter the volute 200 from the two air inlets 201 at both axial ends, which can increase the air volume and improve the working efficiency of the centrifugal fan 1000.

[0077] The diffuser section 200b is connected to the outlet side of the centrifugal impeller 100. The diffuser section 200b includes a first diffuser wall 51 and a second diffuser wall 52 arranged opposite to each other. Both the first diffuser wall 51 and the second diffuser wall 52 extend axially. The diffuser section 200b reduces the flow velocity of the outflowing air, converts dynamic pressure into static pressure, recovers kinetic energy, and increases the static pressure of the airflow, thereby transporting the airflow further and improving the airflow effect.

[0078] The volute tongue 6 can prevent airflow backflow and guide the airflow smoothly to the diffuser section 200b. In addition, the volute tongue 6 can also affect the vortex noise and airflow efficiency of the volute 200.

[0079] In related technologies, centrifugal fans draw air in from the air inlets at both ends of the axial direction of the volute. Due to the airflow characteristics of centrifugal fans, the airflow is not uniformly distributed within the flow cross-section.

[0080] The centrifugal fan 1000 of this embodiment improves the diffuser section 200b and the volute tongue 6. At least the central region of both the volute tongue 6 and the first diffuser wall 51 protrudes axially away from the second diffuser wall 52, thereby increasing the flow area near the central part of the volute 200 compared to the area near the axial end. This increases the flow area in the concentrated airflow region within the volute 200, reducing the airflow velocity in the concentrated airflow region and decreasing aerodynamic noise. Furthermore, it reduces the pressure gradient at different locations along the same cross-section along the airflow direction, minimizing airflow loss and improving energy conversion efficiency.

[0081] In some embodiments of this utility model, the radial distance between the volute tongue 6 and the centrifugal impeller 100 remains unchanged along the axial direction.

[0082] At least the central region in the axial direction protrudes away from the second diffuser wall 52, but the gap between the volute tongue 6 and the effective diameter of the centrifugal impeller 100 remains constant, which can effectively guide the airflow to be discharged more smoothly from the volute 200, reduce the turbulence of the airflow at the outlet, and reduce the flow resistance; at the same time, it prevents the airflow backflow, the pressure of the outlet airflow is more stable, reduces pressure fluctuations, and improves the stability of the output of the centrifugal fan 1000.

[0083] In some embodiments of this utility model, such as Figure 1 and Figure 9As shown, the centrifugal impeller 100 includes an impeller body 100a and a plurality of reinforcing frame 100b spaced apart along the axial direction. The impeller body 100a includes at least one set of blade groups 10, and each set of blade groups 10 includes a plurality of blades 1 spaced apart along the circumferential direction. The outer circumferential contour of the impeller body 100a does not exceed the outer circumferential contour of the blade group 10, and the reinforcing frame 100b protrudes outward from the outer circumferential contour of the impeller body 100a.

[0084] The wind turbine body 100a includes at least one set of blades 10, each set of blades 10 including multiple blades 1 spaced apart circumferentially. The blades 10 are used to drive airflow. The reinforcing frame 100b is used to support and mount the blades 10, providing support and protection. The outer periphery of the wind turbine body 100a does not exceed the outer periphery of the blades 10, while the reinforcing frame 100b protrudes outward from the outer periphery of the wind turbine body 100a. By providing the reinforcing frame 100b, the structural stability of the centrifugal wind turbine 100 can be improved.

[0085] like Figure 8 , Figure 10 and Figure 11 As shown, the volute 200 has a volute section 200a, and the centrifugal impeller 100 is disposed in the volute section 200a. The peripheral wall of the volute section 200a has a recessed groove 55 that is recessed radially outward. The groove wall of the groove 55 extends circumferentially to connect with the volute tongue 6 of the volute 200, and the groove 55 is provided corresponding to the reinforcing frame 100b.

[0086] The centrifugal impeller 100 is rotatably disposed within the volute section 200a, while the reinforcing frame 100b is disposed at the axial center away from the volute 200, resulting in a smaller airflow. A radially outward recessed groove 55 can be formed on the peripheral wall of the volute section 200a, corresponding to the reinforcing frame 100b. The groove 55 can avoid the reinforcing frame 100b without affecting the airflow, thereby reducing the interference caused by the rotation of the volute 200 and the centrifugal impeller 100 and improving the operational reliability of the centrifugal fan 1000.

[0087] In some embodiments of this utility model, such as Figure 1 and Figure 9 As shown, there are two reinforcing frames 100b, which are located at the two ends of the centrifugal impeller 100.

[0088] By providing reinforcing frame 100b at both ends of the centrifugal impeller 100 along its axial direction, the structural stability of the centrifugal impeller 100 can be improved, and the center of gravity of the centrifugal impeller 100 can be stabilized, thereby improving the rotational stability of the centrifugal impeller 100.

[0089] Correspondingly, two radially outward recessed grooves 55 are formed on the peripheral wall of the spiral section 200a. The two grooves 55 are spaced apart along the axial direction, and the grooves 55 correspond one-to-one with the reinforcing frame 100b.

[0090] In some embodiments of this utility model, such as Figure 7 and Figure 8 As shown, the volute 200 has air inlets 201 at both axial ends. The volute 200 has a diffuser section 200b inside. The diffuser section 200b is connected to the air outlet side of the centrifugal impeller 100 and includes a first diffuser wall 51 and a second diffuser wall 52 arranged opposite to each other. One end of the first diffuser wall 51 is connected to the volute tongue 6 of the volute 200, and the other end extends to the air outlet 202 of the volute 200.

[0091] The diffuser section 200b is connected to the outlet side of the centrifugal impeller 100. The diffuser section 200b includes a first diffuser wall 51 and a second diffuser wall 52 arranged opposite each other. Both the first diffuser wall 51 and the second diffuser wall 52 extend axially. The diffuser section 200b reduces the velocity of the outflowing airflow, converts dynamic pressure into static pressure, recovers kinetic energy, and increases the static pressure of the airflow, thereby transporting the airflow further and improving the airflow efficiency. The volute tongue 6 prevents airflow backflow and guides the airflow smoothly to the diffuser section 200b. Furthermore, the volute tongue 6 can also affect the vortex noise and airflow efficiency of the volute casing 200.

[0092] like Figures 8-10 As shown, the volute tongue 6 includes a first wall portion 61 and a second wall portion 62. The first wall portion 61 spans across the opposite sides of the axial center plane M of the volute 200, and the distance between the first wall portion 61 and the second diffuser wall 52 first increases and then decreases along the axial direction, while the distance between the second wall portion 62 and the second diffuser wall 52 remains constant along the axial direction. The axial ends of the first wall portion 61 are respectively connected to the second wall portion 62. The first diffuser wall 51 includes a third wall portion 511 and a fourth wall portion 512. The third wall portion 511 spans across the opposite sides of the axial center plane M of the volute 200, and the distance between the third wall portion 511 and the second diffuser wall 52 first increases and then decreases along the axial direction, while the distance between the fourth wall portion 512 and the second diffuser wall 52 remains constant along the axial direction. The axial ends of the third wall portion 511 are respectively connected to the fourth wall portion 512. Figure 10 As shown, the first wall portion 61 is connected to the third wall portion 511 and is axially offset from the settling tank 55, and the second wall portion 62 is connected between the tank wall of the settling tank 55 and the fourth wall portion 512.

[0093] The centrifugal fan 1000 enters the volute 200 through two inlets 201 at both ends of the axial direction. Therefore, the airflow rate inside the volute 200 first increases and then decreases along the axial direction. Thus, the distance between the first wall 61 and the second diffuser wall 52 is designed to first increase and then decrease along the axial direction of the volute 200, and the distance between the third wall 511 and the second diffuser wall 52 is designed to first increase and then decrease along the axial direction of the volute 200, thereby matching the airflow rate change trend inside the volute 200. This increases the flow area of ​​the concentrated airflow region inside the volute 200, thereby reducing airflow noise and energy loss in the volute 200.

[0094] The second wall portion 62 is connected to both ends of the first wall portion 61 along the axial direction, and the second wall portion 62 is provided corresponding to the reinforcing frame 100b. The air flow at the second wall portion 62 is relatively small. Therefore, the second wall portion 62 is designed such that the distance between the second wall portion 62 and the second diffuser wall 52 remains unchanged along the axial direction. This can reduce the modification of the volute 200, reduce manufacturing costs, and help improve the structural stability of the volute 200.

[0095] Similarly, the fourth wall portion 512 is connected to both ends of the third wall portion 511 in the axial direction, and the fourth wall portion 512 is provided corresponding to the reinforcing frame 100b. The air flow at the fourth wall portion 512 is relatively small. Therefore, the fourth wall portion 512 is designed such that the distance between the fourth wall portion 512 and the second diffuser wall 52 remains unchanged in the axial direction. This can reduce the modification of the volute 200, reduce manufacturing costs, and help improve the structural stability of the volute 200.

[0096] In some embodiments of this utility model, such as Figure 10 and Figure 12 As shown, a flow collecting ring 7 is provided at the air inlet 201 of the volute 200. The flow collecting ring 7 has a flow guiding channel 71. The flow guiding channel 71 has an air inlet end 711 and an air outlet end 712 arranged axially. The flow guiding channel 71 includes a first flow channel section 713 and a second flow channel section 714. The end of the first flow channel section 713 away from the second flow channel section 714 defines the air inlet end 711. The end of the second flow channel section 714 away from the first flow channel section 713 defines the air outlet end 712. The flow area of ​​the first flow channel section 713 decreases along the direction from the air inlet end 711 to the air outlet end 712. The flow area of ​​the second flow channel section 714 increases along the direction from the air inlet end 711 to the air outlet end 712.

[0097] The flow collector 7 is used to guide the airflow into the volute 200. However, the design of the flow collector in the related technology is unreasonable, which makes it impossible for the flow collector to guide the airflow into the volute evenly. The airflow has turbulence on the inner wall of the flow collector and separation vortices on the end face, resulting in high airflow noise.

[0098] In some embodiments of this utility model, the centrifugal fan 1000 improves the structure of the collector ring 7. The collector ring 7 has a guide channel 71. The guide channel guides the airflow outside the volute 200 to the centrifugal impeller 100 installed inside the volute 200. The air inlet end 711 of the guide channel 71 is away from the centrifugal impeller 100, and the air outlet end 712 of the guide channel is close to the centrifugal impeller 100.

[0099] The airflow area within the guide channel 71 first decreases and then increases along the direction from the air inlet 711 to the air outlet 712. This allows the airflow to enter the centrifugal impeller 100 more smoothly, reducing flow losses as the airflow enters the volute 200 from the outside and thus improving the air intake volume.

[0100] In some embodiments of this utility model, such as Figure 12 As shown, the outer peripheral wall of the flow collecting ring 7 includes a first flow collecting wall 72 and a second flow collecting wall 73 that are connected along the axial direction. The first flow collecting wall 72 is set corresponding to the first flow channel section 713, and the second flow collecting wall 73 is set corresponding to the second flow channel section 714. In the longitudinal section of the flow collecting ring 7, the first flow collecting wall 72 extends as an arc and the second flow collecting wall 73 extends as a straight line. The inner peripheral wall of the flow collecting ring 3 includes a third flow collecting wall 74 and a fourth flow collecting wall 75 that are connected along the axial direction X. The third flow collecting wall 74 is set corresponding to the first flow channel section 313, and the fourth flow collecting wall 75 is set corresponding to the second flow channel section 314. In the longitudinal section of the flow collecting ring 3, the third flow collecting wall 74 extends as an arc and the fourth flow collecting wall 75 extends as a curve and extends close to the second flow collecting wall 73 in the direction toward the air outlet.

[0101] The first collector wall 72 extends into an arc, which helps guide the airflow and improves its fluidity; while the second collector wall 73 extends into a straight line, which is beneficial for the manufacturing of the collector ring 7, reducing manufacturing difficulty, minimizing mold usage, and lowering operating costs.

[0102] The third collector wall 74 extends into an arc, which helps guide the airflow and improves its fluidity. Furthermore, the third collector wall 74 is positioned in correspondence with the first collector wall 72, which can improve the structural stability of the collector ring 3. The fourth collector wall 75 extends into a curve, which can improve the guiding effect on the airflow. It also extends close to the second collector wall 73 in the direction towards the air outlet 312, so that the fourth collector wall 75 forms an opening along the extension direction of the airflow, which is conducive to the airflow entering the volute 100.

[0103] In some embodiments of this utility model, such as Figure 12 As shown, the airflow channel 71 is provided with a sound-absorbing sawtooth structure 715 at the air outlet end 712.

[0104] The airflow flows along the inner wall of the collector ring 7 from the inlet end 711 to the outlet end 712, where it begins to detach, and then enters the centrifugal impeller 100. During this process, the airflow generates deturbulence and pressure pulsation, forming vortices and increasing aerodynamic noise. In some embodiments of this invention, a sound-absorbing sawtooth structure 715 is designed at the outlet end 712 of the collector ring 7, which disrupts the periodicity of the vortex, decomposing the large vortex into smaller, more dispersed vortices, thereby reducing the noise intensity of vortex shedding.

[0105] In some embodiments of this utility model, such as Figure 7 and Figure 9 As shown, the volute 200 has a diffuser section 200b, which is connected to the air outlet side of the centrifugal impeller 100 and includes a third diffuser wall 53 and a fourth diffuser wall 54 arranged opposite to each other. The third diffuser wall 53 and the fourth diffuser wall 54 are respectively connected to the two ends of the volute tongue 6 of the volute 200, and both extend away from each other in the direction toward the air outlet 202 of the volute 200.

[0106] The diffuser section 200b reduces the velocity of the outflowing airflow, converts dynamic pressure into static pressure, recovers kinetic energy, and increases the static pressure of the airflow, thereby allowing the airflow to be transported further and improving the airflow effect.

[0107] By extending the third diffuser wall 53 and the fourth diffuser wall 54 away from each other in the direction toward the air outlet 202, the flow area of ​​the diffuser section 200b gradually increases along the airflow direction, thereby reducing the airflow velocity. According to the principle of fluid mechanics, the static pressure increases accordingly when the velocity decreases, thus increasing the static pressure at the air outlet 202 of the centrifugal fan 1000, meeting the static pressure requirements of actual working conditions, and helping to improve the airflow delivery range.

[0108] An air conditioning device according to a third aspect of the present invention includes a centrifugal fan 1000 according to a second aspect of the present invention.

[0109] According to the embodiment of the present invention, by setting the centrifugal fan 1000 of the second aspect, the overall performance of the air conditioning equipment is improved, which is conducive to increasing the air supply volume of the air conditioning equipment and reducing the operating noise of the air conditioning equipment.

[0110] In the description of this utility model, it should be understood that the terms "center", "length", "width", "thickness", "upper", "lower", "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0112] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0113] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0114] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0115] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A centrifugal impeller, characterized in that, include: Multiple blades are arranged circumferentially and spaced apart, with an airflow channel defined between adjacent blades. The airflow channel has a first wall and a second wall that are circumferentially opposite and spaced apart. On the cross-section of the centrifugal impeller, multiple first common tangent circles are formed between the first wall and the second wall of the airflow channel. Each first common tangent circle is tangent to the first wall and the second wall of the airflow channel. In the radial direction of the centrifugal impeller, the two ends of the airflow channel are an inner end and an outer end, respectively. The radius of the multiple first common tangent circles first increases and then decreases along the direction from the inner end to the outer end.

2. The centrifugal impeller according to claim 1, characterized in that, In the radial direction of the centrifugal impeller, the thickness of the blade first increases and then decreases along the direction from the inner end to the outer end.

3. The centrifugal impeller according to claim 2, characterized in that, The thickness of the blade has two side walls, which are respectively the first wall of one of the airflow channels and the second wall of the other airflow channel. On the cross-section of the centrifugal impeller, there are multiple second common tangent circles between the first wall and the second wall of the blade, and each second common tangent circle is tangent to the first wall and the second wall of the blade. In the radial direction of the centrifugal impeller, the radii of the plurality of second common tangent circles first increase and then decrease along the direction from the inner end toward the outer end.

4. The centrifugal impeller according to claim 3, characterized in that, The blade has a centerline in its thickness direction, and the centers of a plurality of second common tangent circles are all located on the centerline. The centerline is divided into a first segment corresponding to the inner end and a second segment corresponding to the outer end by the center of the largest of the plurality of second common tangent circles. The ratio of the length of the first segment to the length of the second segment is x, where 0.3 ≤ x ≤ 0.

6.

5. The centrifugal impeller according to claim 3, characterized in that, The maximum diameter of the plurality of second common tangent circles is Dmax, the minimum diameter is Dmin, and the second common tangent circle with diameter Dmin corresponds to the outer end setting, where 0.3≤Dmin / Dmax≤0.

6.

6. The centrifugal impeller according to claim 3, characterized in that, The blade has a first side and a second side on its two sides, respectively. The first wall is disposed corresponding to the first side, and the second wall is disposed corresponding to the second side. Both the first wall and the second wall are convex toward the second side. The first wall is disposed near the inner end of the first wall at the position with the largest radius corresponding to the first common tangent circle.

7. The centrifugal impeller according to any one of claims 1-6, characterized in that, The blade has a centerline in its thickness direction, and the angle between the tangents at both ends of the centerline toward the blade is α, where 94°≤α≤110°.

8. A centrifugal fan, characterized in that, It includes a volute and a centrifugal impeller according to any one of claims 1-7, wherein the centrifugal impeller is rotatably disposed within the volute.

9. The centrifugal fan according to claim 8, characterized in that, The volute has air inlets at both axial ends. The volute has a diffuser section connected to the air outlet side of the centrifugal impeller and includes a first diffuser wall and a second diffuser wall arranged opposite to each other. One end of the first diffuser wall is connected to the volute tongue of the volute, and the other end extends to the air outlet of the volute. At least the middle region of the volute tongue and the first diffuser wall in the axial direction protrudes away from the second diffuser wall.

10. The centrifugal fan according to claim 9, characterized in that, The radial distance between the volute tongue and the centrifugal impeller remains constant along the axial direction.

11. The centrifugal fan according to claim 8, characterized in that, The centrifugal impeller includes an impeller body and a plurality of reinforcing frames spaced apart along the axial direction. The impeller body includes at least one set of blades, and each set of blades includes a plurality of blades spaced apart along the circumferential direction. The outer circumferential contour of the impeller body does not exceed the outer circumferential contour of the blade set. The reinforcing frames protrude outward from the outer circumferential contour of the impeller body. The volute has a volute section inside, and the centrifugal impeller is disposed in the volute section. The circumferential wall of the volute section forms a recessed groove that is recessed outward along the radial direction. The groove wall extends circumferentially to connect with the volute tongue of the volute, and the groove is provided corresponding to the reinforcing frames.

12. The centrifugal fan according to claim 11, characterized in that, The reinforcing frame consists of two parts, located at opposite ends of the centrifugal impeller.

13. The centrifugal fan according to claim 12, characterized in that, The volute has air inlets at both axial ends, and a diffuser section inside the volute is connected to the air outlet side of the centrifugal impeller. The diffuser section includes a first diffuser wall and a second diffuser wall arranged opposite to each other. One end of the first diffuser wall is connected to the volute tongue of the volute, and the other end extends to the air outlet of the volute. The volute tongue includes a first wall portion and a second wall portion. The first wall portion spans across the opposite sides of the central surface of the volute shell in the axial direction. The distance between the first wall portion and the second diffuser wall increases first and then decreases along the axial direction. The distance between the second wall portion and the second diffuser wall remains unchanged along the axial direction. The second wall portion is connected to both ends of the first wall portion in the axial direction. The first diffuser wall includes a third wall portion and a fourth wall portion. The third wall portion spans across the opposite sides of the central surface of the volute in the axial direction. The distance between the third wall portion and the second diffuser wall increases first and then decreases along the axial direction. The distance between the fourth wall portion and the second diffuser wall remains unchanged along the axial direction. The fourth wall portion is connected to both ends of the third wall portion in the axial direction. The first wall portion is connected to the third wall portion and is axially offset from the settling tank. The second wall portion is connected between the tank wall and the fourth wall portion.

14. The centrifugal fan according to claim 8, characterized in that, The volute is provided with a flow collecting ring at the air inlet, and the flow collecting ring has a flow guiding channel. The flow guiding channel has an air inlet end and an air outlet end that are spaced apart along the axial direction. The flow guiding channel includes a first flow channel section and a second flow channel section. The end of the first flow channel section away from the second flow channel section defines the air inlet end, and the end of the second flow channel section away from the first flow channel section defines the air outlet end. The flow area of ​​the first flow channel section decreases along the direction from the air inlet end to the air outlet end, and the flow area of ​​the second flow channel section increases along the direction from the air inlet end to the air outlet end.

15. The centrifugal fan according to claim 14, characterized in that, The outer peripheral wall of the flow collecting ring includes a first flow collecting wall and a second flow collecting wall that are axially connected. The first flow collecting wall is set corresponding to the first flow channel segment, and the second flow collecting wall is set corresponding to the second flow channel segment. In the longitudinal section of the flow collecting ring, the first flow collecting wall extends as an arc and the second flow collecting wall extends as a straight line. The inner peripheral wall of the flow collecting ring includes a third flow collecting wall and a fourth flow collecting wall that are axially connected. The third flow collecting wall is set corresponding to the first flow channel segment, and the fourth flow collecting wall is set corresponding to the second flow channel segment. In the longitudinal section of the flow collecting ring, the third flow collecting wall extends as an arc and the fourth flow collecting wall extends as a curve and extends close to the second flow collecting wall in the direction toward the air outlet end. And / or, the airflow channel is provided with a sound-absorbing serrated structure at the air outlet end.

16. The centrifugal fan according to any one of claims 8-15, characterized in that, The volute has a diffuser section connected to the air outlet side of the centrifugal impeller, and includes a third diffuser wall and a fourth diffuser wall arranged opposite to each other. The third diffuser wall and the fourth diffuser wall are respectively connected to the two ends of the volute tongue of the volute, and both extend away from each other in the direction toward the air outlet of the volute.

17. An air conditioning device, characterized in that, Includes the centrifugal fan according to any one of claims 8-16.

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