Centrifugal fan impeller structure and centrifugal fan

Abstract

The present invention provides a centrifugal fan impeller structure and a centrifugal fan. The impeller structure includes an impeller body, the impeller body includes blades, and the blades include a planar segment near their root and a curved segment near their tip, with a smooth transition between the planar segment and the curved segment. Based on the technical solution of the present invention, on the one hand, without additionally increasing the size of the blades, the curved segment increases the contact area between the blades and the airflow, thereby improving pressure and air volume. On the other hand, the smooth transition between the planar segment and the curved segment reduces the noise generated when the blades come into contact with the air, thereby achieving noise reduction. These two improvements overall improve the performance of the impeller structure and the corresponding centrifugal fan.

Description

Technical Field

[0001] The present invention relates to the technical field of centrifugal fan impellers, and in particular to a centrifugal fan impeller structure and a centrifugal fan. Background Art

[0002] Centrifugal fans accelerate gas using high-speed rotating impellers and are widely used in the home appliance industry. In the prior art, the blade structures inside the impellers are all straight or arc-shaped plate-like blades. When the impeller rotates, the internal moving airflow is simultaneously affected by the fluid viscosity, adverse pressure gradient, and rotational Coriolis force, resulting in flow separation and the formation of secondary vortices, which can lead to low impeller efficiency and thus affect the aerodynamic performance and operating noise of the fan. At the same time, under the conditions of the same impeller diameter and blade thickness, the smaller the contact area between the blade and the medium, the greater the energy loss during the conversion process, and at the same time, there are problems such as low pressure, insufficient air volume, and low motor efficiency.

[0003] To address the above problems, the impeller blade structure needs to be designed to reduce boundary layer separation, lower the discrete noise of the centrifugal fan, and at the same time meet the fan's high pressure and large air volume requirements. Summary of the Invention

[0004] In order to solve the problems of low working efficiency, low aerodynamic performance and high noise in the fan impeller in the prior art, the present application proposes a centrifugal fan impeller structure and a centrifugal fan.

[0005] In a first aspect, the present invention proposes a centrifugal fan impeller structure, comprising an impeller body, wherein the impeller body comprises blades, wherein the blades comprise a planar segment near their roots and an arc segment near their tips, and a smooth transition is formed between the planar segment and the arc segment.

[0006] In one embodiment, the blade is a symmetrical tapered structure with gradually increasing width from its root to its tip. This ensures that the tip of the blade is sufficiently large without increasing the root width, reducing the blade's own weight and improving the performance of the impeller structure.

[0007] In one embodiment, the impeller body further includes an inner disk and an outer disk. A plurality of blades are evenly distributed circumferentially in the annular region between the inner disk and the outer disk, and the arcuate segments of all blades are oriented in the same circumferential direction. This embodiment secures the ends of the blades using the inner disk and the outer disk, ensuring the stability and reliability of the impeller structure.

[0008] In one embodiment, the root of the blade connects to the outer circumferential surface of the inner impeller to form a first connection point. A blade inlet angle α between a tangent to the outer circumferential surface of the inner impeller at the first connection point and the plane of the planar segment is defined, with the angle being 25°≤α≤35°. This embodiment helps reduce boundary layer separation, vortices, and noise during operation of the centrifugal fan.

[0009] In one embodiment, the tips of the blades connect to the inner circumferential surface of the outer disk to form a second connection point. A tangent to the inner circumferential surface of the outer disk at the second connection point and a tangent to the arc corresponding to the arc segment at the second connection point form an exit angle β, where 52°≤β≤60°. This embodiment helps reduce boundary layer separation, vortices, and noise during operation of the centrifugal fan.

[0010] In one embodiment, the roots of the blades connect to the outer circumference of the inner disk, forming a first connection point. The angle between a line passing through the center of the inner disk and the first connection point and a tangent to the arc corresponding to the arc segment passing through the center of the inner disk is the blade wrap angle θ, where 26°≤θ≤31°. This embodiment helps reduce boundary layer separation, vortices, and noise during operation of the centrifugal fan.

[0011] In one embodiment, the roots of the blades connect to the outer circumference of the inner disk, forming a first connection point. The angle between two lines connecting the two first connection points corresponding to two adjacent blades and the center of the inner disk is the blade distribution angle γ, where γ = 10°. This embodiment helps reduce boundary layer separation, vortices, and noise during operation of the centrifugal fan.

[0012] In one embodiment, the projection trajectory of the portion of the blade's outer contour between the root and tip onto a target plane matches a branch of a hyperbola; the target plane is a plane passing through both the axis of the inner impeller and the connection point between the blade's root and the inner impeller. This embodiment effectively reduces the degree of flow separation within the impeller flow channel, improves centrifugal impeller efficiency, and reduces eddy current noise.

[0013] In one embodiment, a middle portion of the root of the blade has an assembly opening for connecting to the inner wheel disc, and the assembly opening passes through the blade in a direction perpendicular to the plane where the planar segment is located.

[0014] In one embodiment, the minimum vertical distance from the wall of the assembly opening to the edge of the blade root is h, half the maximum width of the blade tip is H, and 0.1H≤h≤0.15H. This embodiment enhances structural strength while ensuring outlet air pressure and air volume, thereby improving the reliability of the impeller structure.

[0015] In one embodiment, the inner wheel disc has a protruding connecting portion on its circumferential surface for matching with the assembly opening, and the connecting portion can be snapped into the assembly opening.

[0016] In one embodiment, it also includes a volute for accommodating the impeller body, the extension path of the volute matches the Archimedean spiral, the volute has an extension starting point with the smallest distance from the impeller body and an extension end point with the largest distance from the impeller body, and an air outlet is between the extension starting point and the extension end point.

[0017] In one embodiment, the air outlet is provided with an air guide structure comprising an air guide plate and a volute tongue. The air guide plate is tangent to the volute at the end of the extension, and the volute tongue is provided at the starting point of the extension. This embodiment, combined with a volute structure that matches the Archimedean spiral, allows tangential air discharge to increase the internal air pressure of the volute, thereby overcoming air resistance within the air duct of the air supply device and improving the operating efficiency of the centrifugal fan.

[0018] In one embodiment, the minimum distance between the volute and the impeller body is δ, where δ = (0.05-0.1)D, where D is the outer diameter of the impeller body. This embodiment can reduce the noise of the centrifugal fan during operation, thereby improving the user experience; it also reduces air leakage from the volute, increases the air output of the centrifugal fan, and thus improves the operating efficiency of the centrifugal fan.

[0019] In one embodiment, the angle between the two lines connecting the center of the impeller body at the extension start point and the extension end point is 90°. Through this embodiment, the size of the air outlet duct is guaranteed to the greatest extent, which is conducive to increasing the air volume.

[0020] In a second aspect, the present invention provides a centrifugal fan comprising the above-mentioned impeller structure.

[0021] The above technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0022] The centrifugal fan impeller structure and centrifugal fan provided by the present invention have at least the following beneficial effects compared with the prior art:

[0023] A centrifugal fan impeller structure and a centrifugal fan of the present invention are based on a blade structure that combines a plane segment and a curved segment. On the one hand, without additionally increasing the size of the blade, the curved segment increases the contact area between the blade and the airflow, thereby achieving an increase in pressure and air volume. On the other hand, the smooth transition between the plane segment and the curved segment makes the noise generated when the blade contacts the air smaller, thereby achieving noise reduction. Through the improvements in the above two aspects, the performance of the impeller structure and the corresponding centrifugal fan are improved as a whole. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be described in more detail below based on embodiments and with reference to the accompanying drawings, wherein:

[0025] Figure 1 A schematic structural diagram showing an impeller body of the impeller structure of the present invention;

[0026] Figure 2 A schematic cross-sectional view of the impeller body of the impeller structure of the present invention is shown;

[0027] Figure 3 Shows the overall structural schematic diagram of the impeller structure of the present invention;

[0028] Figure 4 An exploded view of the impeller structure of the present invention is shown;

[0029] Figure 5 It shows the velocity cloud diagram of the centrifugal fan corresponding to the impeller structure of the present invention when it is running;

[0030] Figure 6 The velocity cloud diagram of the centrifugal fan during operation corresponding to the existing impeller structure is shown.

[0031] In the drawings, like reference numerals are used for like parts, but the drawings are not necessarily true to scale.

[0032] Reference numerals:

[0033] 10-impeller body, 11-blade, 111-plane segment, 112-arc segment, 12-inner wheel disc, 121-connecting part, 13-outer wheel disc, 20-volute, 201-front shell, 202-rear shell, 21-extension starting point, 22-extension end point, 23-air outlet, 24-air inlet, 30-air guide structure, 31-volute tongue, 32-air guide plate, 40-base circle. DETAILED DESCRIPTION

[0034] The present invention will be further described below with reference to the accompanying drawings.

[0035] An embodiment of the present invention provides a centrifugal fan impeller structure, including an impeller body 10, the impeller body 10 includes a blade 11, the blade 11 includes a planar segment 111 near its root and an arc segment 112 near its tip, and a smooth transition is formed between the planar segment 111 and the arc segment 112.

[0036] Specifically, as shown in the attached figure Figure 1 As shown, the impeller structure of the present invention primarily improves the structure of blade 11. Blade 11 utilizes a structure combining a flat section 111 with a curved section 112. Without increasing the size of blade 11, the curved section 112 at the tip of blade 11 increases the contact area with the airflow, thereby increasing the airflow pressure and air volume, thereby meeting the corresponding usage requirements. Furthermore, the smooth transition between flat section 111 and curved section 112 avoids excessive resistance when in contact with the airflow, thereby helping to reduce noise.

[0037] In one embodiment, the blade 11 as a whole is a symmetrical conical structure with a width gradually increasing from its root to its tip.

[0038] Specifically, in the centrifugal fan corresponding to the impeller structure of the present invention, air enters from the root end of the blade 11 and exits from the tip end. Therefore, the pressure and volume of the air outlet mainly depend on the structure of the tip end of the blade 11. Therefore, it is mainly necessary to ensure that the contact area between the tip part of the blade 11 and the airflow is large enough.

[0039] As shown in the attached picture Figure 2 As shown, in this embodiment, the blade 11 is further configured as a plane-symmetrical conical structure with a small root width and a large tip width, that is, the width of the arc segment 112 is greater than the width of the straight segment, ensuring that the area of ​​the tip portion of the blade 11 is large enough without additionally increasing the root width, thereby reducing the deadweight of the blade 11 and improving the performance of the impeller structure.

[0040] In one embodiment, the impeller body 10 further includes an inner wheel disc 12 and an outer wheel disc 13 , and a plurality of blades 11 are evenly distributed circumferentially in the annular area between the inner wheel disc 12 and the outer wheel disc 13 , and the arc surface segments 112 of all blades 11 have the same circumferential orientation.

[0041] Specifically, as shown in the accompanying drawings Figure 1 As shown, blades 11 are fixed to the annular area between inner disk 12 and outer disk 13, with their roots fixedly connected to inner disk 12 and their tips fixedly connected to outer disk 13. Blades 11 are tilted, meaning that the overall extension direction of blades 11 is not along the radial direction of inner disk 12, but rather at a certain angle to the radial direction of inner disk 12. Furthermore, the cambered segments 112 of multiple blades 11 are oriented in the same circumferential direction, meaning that all cambered segments 112 of blades 11 have the same orientation relative to the concave side surface, and their orientation corresponds to the direction of rotation of inner disk 12.

[0042] Furthermore, as shown in the accompanying drawings Figure 1 As shown, both the inner wheel disc 12 and the outer wheel disc 13 are annular structures, and the radial thickness of the inner wheel disc 12 is greater than the radial thickness of the outer wheel disc 13. Because the inner wheel disc 12 plays the role of transmitting torque, its thickness is increased to enhance its structural strength and prevent cracking and deformation.

[0043] In one embodiment, as shown in the accompanying drawings Figure 1 As shown, the root of the blade 11 is connected to the outer circumferential surface of the inner wheel disc 12 and forms a first connection point, and the tangent line of the outer circumferential surface of the inner wheel disc 12 at the first connection point and the plane where the plane segment 111 is located have an inlet angle α of the blade 11, 25°≤α≤35°.

[0044] Furthermore, as shown in the accompanying drawings Figure 1 As shown, the tip of the blade 11 is connected to the inner circumferential surface of the outer wheel disc 13 and forms a second connection point. The tangent of the inner circumferential surface of the outer wheel disc 13 at the second connection point and the arc corresponding to the arc surface segment 112 at the second connection point have an outlet angle β between them, 52°≤β≤60°.

[0045] Furthermore, as shown in the accompanying drawings Figure 1 As shown, the root of the blade 11 is connected to the outer circumferential surface of the inner wheel disc 12 and forms a first connection point. The angle between the straight line passing through the center of the inner wheel disc 12 and the first connection point and the tangent of the arc corresponding to the arc segment 112 passing through the center of the inner wheel disc 12 is the blade 11 wrap angle θ, 26°≤θ≤31°.

[0046] Furthermore, as shown in the accompanying drawings Figure 1 As shown, the root of the blade 11 is connected to the outer circumferential surface of the inner wheel disc 12 and forms a first connection point. The angle between the two connecting lines connecting the two first connection points corresponding to two adjacent blades 11 to the center of the inner wheel disc 12 is the blade 11 distribution angle γ, γ = 10°.

[0047] Specifically, the above-mentioned targeted design of each angle of the blade 11 is conducive to reducing boundary layer separation, reducing vortices and reducing noise during operation of the centrifugal fan.

[0048] In one embodiment, the projection trajectory of the portion of the outer contour of the blade 11 between the root and the tip on the target plane matches a branch of a hyperbola;

[0049] The target plane is a plane that passes through the axis of the inner wheel disk 12 and the connection point between the root of the corresponding blade 11 and the inner wheel disk 12 .

[0050] Specifically, as shown in FIG. Figure 2As shown, the target plane is a cross section of the inner impeller 12 axis passing through the connection point between the root of blade 11 and the inner impeller 12. The projection trajectory of the outer contour line of blade 11 extending from the root to the tip on this cross section matches one branch of the hyperbola. For the two blades 11 on either side of the inner impeller 12 whose connection points are within the same cross section, the projection trajectory of their outer contour lines on the corresponding cross sections matches the hyperbola. This structure can effectively reduce the degree of flow separation in the impeller flow channel, improve the efficiency of the centrifugal impeller, and reduce eddy current noise.

[0051] In one embodiment, a middle portion of the root of the blade 11 has an assembly opening for connecting to the inner wheel disc 12 , and the assembly opening passes through the blade 11 in a direction perpendicular to the plane where the planar section 111 is located.

[0052] Preferably, the minimum vertical distance from the wall surface on one side of the assembly opening to the root edge of the blade 11 is h, half of the maximum width of the tip of the blade 11 is H, and 0.1H≤h≤0.15H.

[0053] Specifically, as shown in the accompanying drawings Figure 1 and Figure 2 As shown, the root of blade 11 has an assembly opening, flanked by two remaining portions of equal width at the root of blade 11. The width of each remaining portion must be maintained at a certain value to ensure the strength of the root of blade 11. The strength of the root of blade 11 is related to its resistance to airflow, specifically the width of the tip of blade 11. A wider tip of blade 11 theoretically improves airflow performance, but also increases the strength requirement for the root, leading to a need to strike a balance between strength and performance.

[0054] Through experiments, it is found that when 0.1H≤h≤0.15H, the balance between the strength of the blade and its working performance is optimal.

[0055] In one embodiment, a protruding connecting portion 121 for matching with the assembly opening is provided on the circumferential surface of the inner wheel disc 12 , and the connecting portion 121 can be snapped into the assembly opening.

[0056] Specifically, as shown in the attached figure Figure 1 and Figure 2 As shown, the connecting portion 121 protrudes outward from the outer circumference of the inner wheel disc 12, and its structure can be adaptively set. Considering the convenience of manufacturing and assembly, the connecting portion 121 is set as an annular plate structure that continuously extends along the circumference.

[0057] In one embodiment, a volute 20 is further included to accommodate the impeller body 10. The extension path of the volute 20 matches the Archimedean spiral. The volute 20 has an extension starting point 21 with the smallest distance from the impeller body 10 and an extension end point 22 with the largest distance from the impeller body 10. An air outlet 23 is located between the extension starting point 21 and the extension end point 22.

[0058] Specifically, as shown in FIG. Figure 3 As shown, the impeller structure also includes a volute 20 that accommodates the impeller body 10. The cavity inside the volute 20 is not only used to install the impeller body 10, but also to guide the airflow. The volute 20 adopts a continuous extension structure that matches the Archimedean spiral, which is conducive to guiding the airflow.

[0059] In one embodiment, an air guide structure 30 is provided at the air outlet 23 , and the air guide structure 30 includes an air guide plate 32 and a volute tongue 31 . The air guide plate 32 is tangent to the volute 20 at the extension end 22 , and the volute tongue 31 is provided at the extension starting point 21 .

[0060] Specifically, as shown in the accompanying drawings Figure 3 As shown, the air guide structure 30 includes a curved volute tongue 31 and a straight air guide plate 32, forming an air outlet channel between the two. The air outlet channel extends along the tangent direction of the volute 20 at the extension end 22. Combined with the volute 20 structure that matches the Archimedean spiral, the tangential air outlet can increase the internal wind pressure of the volute 20, overcome the air resistance in the air supply device duct, and thus improve the operating efficiency of the centrifugal fan.

[0061] Preferably, the angle between the two connecting lines connecting the extension starting point 21 and the extension end point 22 to the center of the impeller body 10 is 90°.

[0062] Furthermore, the volute 20 is formed by snapping together a front shell 201 and a rear shell 202. The center of the front shell 201 has an air inlet 24. The air flow enters from the center along the axis direction of the impeller body 10 and exits along the tangential direction of the impeller body 10 along the air outlet 23.

[0063] In one embodiment, the minimum value of the distance between the volute 20 and the impeller body 10 is δ, δ=(0.05-0.1)D, where D is the outer diameter of the impeller body 10 .

[0064] Specifically, the point where the distance between the volute 20 and the impeller body 10 is the smallest corresponds to the position of the volute tongue 31, which can reduce the noise during operation of the centrifugal fan, thereby improving the user experience; at the same time, it can slow down the air leakage of the volute 20, increase the air output of the centrifugal fan, and thus improve the working efficiency of the centrifugal fan.

[0065] Furthermore, as shown in the accompanying drawings Figure 3As shown, the starting point of the Archimedean spiral corresponding to the volute 20, that is, the position of the extension starting point 21 of the volute 20, is determined with reference to the base circle 40. That is, the extension starting point 21 is located on the circumference of the base circle 40. The size of the base circle 40 is determined by the size of the impeller body 10, that is, the radius of the base circle 40 = the radius of the impeller body 10 + δ, δ = (0.05-0.1)D, where D is the outer diameter of the impeller body 10.

[0066] The impeller structure of the present invention obtained based on the above improvements has a greater performance improvement in actual application compared with the existing impeller structure. Figure 5 and Figure 6 The speed cloud diagram of the centrifugal fan corresponding to the corresponding impeller structure is shown in the figure. At 3500rpm, the performance parameters of the two are compared as shown in the following table:

[0067] Air volume Torque noise Centrifugal fan of the present invention 47.1 5.34 87 / 88 Universal arc plate centrifugal fan 43.22 5 110 / 99

[0068] from Figure 5 and Figure 6 It can be seen from the speed cloud diagram shown that the speed distribution of the centrifugal fan corresponding to the impeller structure of the present invention is more uniform. Compared with the currently common centrifugal fans with arc blades, the impeller structure of the present invention and the corresponding centrifugal fan have greatly improved in two performance indicators: noise and air volume.

[0069] An embodiment of the present invention further provides a centrifugal fan, which includes the above-mentioned impeller structure and thus has all the technical effects thereof.

[0070] In the description of the present invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "back", "inside", "outside", "left", "right", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the present invention.

[0071] Although the present invention is described herein with reference to specific embodiments, it should be understood that these embodiments are merely illustrative of the principles and applications of the invention. It should be understood that many modifications may be made to the illustrative embodiments, and that other arrangements may be devised, without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that the various dependent claims and features described herein may be combined in ways other than those described in the original claims. It should also be understood that features described in conjunction with individual embodiments may be employed in conjunction with other described embodiments.

Claims

1. A centrifugal fan impeller structure, comprising an impeller body, characterized in that: The impeller body includes a blade, and the blade includes a flat section near its root and a curved section near its tip, and there is a smooth transition between the flat section and the curved section; The impeller body further comprises an inner wheel disc and an outer wheel disc, wherein a plurality of blades are evenly distributed along the circumferential direction in the annular region between the inner wheel disc and the outer wheel disc, and the arc surface segments of all the blades have the same orientation in the circumferential direction; The blade as a whole is a symmetrical cone-shaped structure with gradually increasing width from the root to the tip; The projection trajectory of the portion of the outer contour of the blade between the root and the tip on the target plane matches a branch of a hyperbola; wherein the target plane is a plane passing through the axis of the inner wheel disk and the corresponding connection point between the root of the blade and the inner wheel disk; The middle portion of the blade root has an assembly opening for connecting to the inner wheel disc, the assembly opening passes through the blade in a direction perpendicular to the plane of the planar segment, the minimum vertical distance from a wall surface on one side of the assembly opening to the edge of the blade root is h, half of the maximum width of the blade tip is H, and 0.1H≤h≤0.15H; The inner wheel disc has a protruding connecting portion on its circumferential surface for matching with the assembly opening. The connecting portion can be inserted into the assembly opening and protrudes outward from the outer circumferential surface of the inner wheel disc.

2. The centrifugal fan impeller structure according to claim 1, characterized in that: The root of the blade is connected to the outer circumferential surface of the inner wheel disc and forms a first connection point. A blade inlet angle α is formed between a tangent line of the outer circumferential surface of the inner wheel disc at the first connection point and the plane where the plane segment is located, and the angle is 25°≤α≤35°.

3. The centrifugal fan impeller structure according to claim 1, characterized in that: The tip of the blade is connected to the inner circumferential surface of the outer wheel disc and forms a second connection point. The tangent of the inner circumferential surface of the outer wheel disc at the second connection point and the tangent of the arc corresponding to the arc surface segment at the second connection point have an outlet angle β, 52°≤β≤60°.

4. The centrifugal fan impeller structure according to claim 1, characterized in that: The root of the blade is connected to the outer circumferential surface of the inner wheel disc and forms a first connection point. The angle between the straight line passing through the center of the inner wheel disc and the first connection point and the tangent of the arc corresponding to the arc surface segment passing through the center of the inner wheel disc is the blade wrap angle θ, 26°≤θ≤31°.

5. The centrifugal fan impeller structure according to claim 1, characterized in that: The root of the blade is connected to the outer circumferential surface of the inner wheel disc and forms a first connection point. The angle between the two connecting lines connecting the two first connection points corresponding to two adjacent blades to the center of the inner wheel disc is the blade distribution angle γ, γ=10°.

6. The centrifugal fan impeller structure according to claim 1, characterized in that: It also includes a volute for accommodating the impeller body, wherein the extension path of the volute matches the Archimedean spiral, and the volute has an extension starting point with the smallest distance from the impeller body and an extension end point with the largest distance from the impeller body, and an air outlet is between the extension starting point and the extension end point.

7. The centrifugal fan impeller structure according to claim 6, characterized in that: An air guide structure is provided at the air outlet, and the air guide structure includes an air guide plate and a volute tongue. The air guide plate is tangent to the volute at the extension end point, and the volute tongue is provided at the extension starting point.

8. The centrifugal fan impeller structure according to claim 6 or 7, characterized in that: The minimum value of the distance between the volute and the impeller body is δ, δ=(0.05~0.1)D, where D is the outer diameter of the impeller body.

9. The centrifugal fan impeller structure according to claim 6 or 7, characterized in that: The angle between the two connecting lines connecting the extension starting point and the extension end point to the center of the impeller body is 90°.

10. A centrifugal fan, characterized in that: It comprises the impeller structure according to any one of claims 1 to 9.

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