Blade, impeller assembly and centrifugal fan

Abstract

The invention discloses a blade, an impeller assembly and a centrifugal fan. The blade comprises a blade body, the two ends of the blade body in the first direction are the first end and the second end respectively, the first end is provided with a first end face, the second end is provided with a second end face, and a plane parallel to the first end face and the second end face is defined as an interception plane; the blade body comprises a first air guide face and a second air guide face which are arranged oppositely, the intercepting plane intercepts the first air guide face to obtain a first air guide line, and the first air guide line comprises a first arc line section and a straight line section which are connected with each other; the intercepting plane intercepts the second air guide surface to obtain a second air guide line, the second air guide line comprises at least two arc line sections, and the curvature radiuses of the at least two arc line sections are different. According to the blade, through the combination of the straight line sections and the arc line sections of the first air guide lines and the cooperation of the multiple arc line sections with different curvature radiuses of the second air guide lines, air flow is finely regulated and controlled, the air flow separation phenomenon can be effectively restrained, vortex generation is reduced, and therefore energy loss is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of fans, and in particular relates to a blade, an impeller assembly and a centrifugal fan. Background Art

[0002] Currently, the air guide surface of traditional centrifugal fan blades typically utilizes a single curvature arc segment design. From a fluid dynamics perspective, this design has significant limitations. During centrifugal fan operation, the velocity and pressure distribution of airflow along the blade's air guide surface constantly change. A single curvature air guide surface struggles to balance velocity differences between different blade sections, preventing precise matching of velocity and pressure distribution across different regions.

[0003] For example, when the airflow passes through the blades, in the blade inlet area, since the single curvature wind guide surface cannot provide an ideal guiding angle for the airflow, when the airflow enters the channel between the blades, the angle with the wind guide surface is often too large or too small, and the impact angle is unreasonable, causing the airflow to be unable to adhere smoothly to the wind guide surface, thereby generating impact loss and increasing energy consumption.

[0004] At the blade outlet, the airflow must make a large turn to exit the fan. The single-curvature air guide surface has a single curvature change at the outlet, making it impossible to achieve a smooth transition and guidance of the airflow. The sudden change in curvature causes the airflow to separate during the turn, resulting in wake loss. The airflow in the wake area becomes turbulent, forming strong vortices that not only increase air flow resistance but also significantly reduce the fan's aerodynamic efficiency. Furthermore, the vortices generated by airflow separation can also cause airflow pulsation. These pulsating airflows periodically impact the blades and other fan components, generating high-frequency noise. Summary of the Invention

[0005] One of the purposes of the present invention is to disclose a blade that can finely control the airflow through the combination of straight segments and arc segments of the first air guide line and the coordination of multiple arc segments with different curvature radii of the second air guide line, thereby effectively suppressing the airflow separation phenomenon, reducing the generation of vortexes, and thus reducing energy loss.

[0006] The second purpose of the present invention is to disclose an impeller assembly whose blade structure effectively suppresses the airflow separation phenomenon, significantly reduces the generation of vortexes, and fundamentally reduces the energy loss caused by airflow turbulence.

[0007] A third objective of the present invention is to disclose a centrifugal fan whose impeller assembly, during airflow guidance, effectively suppresses airflow separation through its blade structure, significantly reducing the generation of eddies, and thus fundamentally reducing energy loss due to airflow turbulence. Because the blade structure effectively suppresses airflow separation and eddies, vibrations caused by unstable airflow during operation of the impeller assembly are significantly reduced, significantly reducing fan noise.

[0008] To achieve one of the above objectives, the present invention discloses a blade, comprising a blade body, wherein two ends of the blade body in a first direction are respectively a first end and a second end, the first end having a first end surface, the second end having a second end surface, and a plane parallel to the first end surface and the second end surface is defined as a cutting plane; The blade body includes a first wind guide surface and a second wind guide surface that are arranged back to back with each other. The intercepting plane intercepts the first wind guide surface to obtain a first wind guide line, and the first wind guide line includes a first arc segment and a straight line segment that are connected to each other; the intercepting plane intercepts the second wind guide surface to obtain a second wind guide line, and the second wind guide line includes at least two arc segments, and the curvature radii of the at least two arc segments are different.

[0009] As an optional implementation, the connecting point of the first arc segment and the straight line segment is defined as point A, and the tangent line L1 of the first arc segment at point A coincides with the straight line where the straight line segment is located.

[0010] As an optional embodiment, the blade body includes a first section and a second section that are connected to each other, a plane section is provided on one side of the first section, and a first arc surface section is provided on one side of the second section; the first arc surface section is connected with the plane section to form the first wind guide surface; the intercepting plane intercepts the plane section to obtain the straight line segment, and the intercepting plane intercepts the first arc surface section to obtain the first arc line segment.

[0011] As an optional implementation, along the first direction, the curvature radii of the first arc segments obtained by intercepting the first arc segment by each of the intercepting planes are all the same.

[0012] As an optional implementation manner, the straight line direction in which the straight line segment is located is defined as a second direction, and along the first direction, the width of the first segment in the second direction gradually decreases.

[0013] As an optional embodiment, the second wind-guiding surface includes three arc surface segments, which are the second arc surface segment, the third arc surface segment and the fourth arc surface segment connected in sequence. The intercepting plane intercepts the second arc surface segment to obtain the second arc line segment, the intercepting plane intercepts the third arc surface segment to obtain the third arc line segment, and the intercepting plane intercepts the fourth arc surface segment to obtain the fourth arc line segment; the curvature radius of the second arc line segment is smaller than the curvature radius of the third arc line segment, and the curvature radius of the third arc line segment is larger than the curvature radius of the fourth arc line segment.

[0014] As an optional embodiment, along the first direction, the curvature radii of the second arc segments obtained by the cutting plane intercepting the second arc surface segment are all the same; the curvature radii of the third arc segments obtained by the cutting plane intercepting the third arc surface segment are all the same; and the curvature radii of the fourth arc segments obtained by the cutting plane intercepting the fourth arc surface segment are all the same.

[0015] As an optional embodiment, the inlet angle of the blade body is α, and the value range of α is 25°<α<49°; the outlet angle of the blade body is β, and the value range of β is 90°<β<140°.

[0016] As an optional implementation, along the first direction, the inlet angle α on each intercepting plane gradually decreases, and the outlet angle β gradually increases.

[0017] In order to achieve the second of the above-mentioned purposes, the present invention discloses an impeller assembly, including a mounting plate and a plurality of blades as described above, wherein the mounting plate has a central axis and a mounting surface, and the plurality of blade bodies are arranged at equal intervals along the circumferential direction around the central axis and are mounted on the mounting surface through the first end.

[0018] In order to achieve the third of the above objectives, the present invention discloses a centrifugal fan, comprising a volute and the impeller assembly as described above, wherein the impeller assembly is mounted on the volute.

[0019] As an optional embodiment, the centrifugal fan also includes an air guide member, the volute has an installation port, an air outlet and an air cavity, the air guide member is installed at the installation port, the impeller assembly is installed in the air cavity, and the air guide member and the impeller assembly are coaxially arranged; the air guide member is provided with an air guide channel, the air guide channel is connected with the air cavity and guides the airflow into the air cavity, the air outlet is connected with the air cavity and guides the airflow out of the air cavity; the air guide member is provided with a blocking section on the side facing the impeller assembly, the blocking section is spaced apart from the second end of the blade body, and forms an anti-leakage channel.

[0020] Compared with the prior art, the present invention has the following beneficial effects: 1. The blade of the present invention can finely control the airflow by arranging straight segments and arc segments on the first air guide line of the blade body and arranging multiple arc segments with different curvature radii on the second air guide line, which can effectively suppress the airflow separation phenomenon, reduce the generation of vortex, and thus reduce energy loss.

[0021] 2. The impeller assembly of the present invention effectively suppresses airflow separation through its blade structure, significantly reducing the generation of vortices and fundamentally reducing energy loss caused by airflow turbulence. Because the blade structure effectively suppresses airflow separation and vortices, vibrations caused by unstable airflow during operation of the impeller assembly are significantly reduced.

[0022] 3. During the airflow guidance process, the impeller assembly of the centrifugal fan of the present invention effectively suppresses airflow separation through its blade structure, significantly reducing the generation of eddies, and thus fundamentally reducing energy loss caused by airflow turbulence. Because the blade structure effectively suppresses airflow separation and eddies, the vibration generated by unstable airflow during operation of the impeller assembly is significantly reduced, significantly reducing fan noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0024] Figure 1 is a schematic structural diagram of a blade body cut by multiple cutting planes according to a first embodiment of the present invention; Figure 2 This is a schematic structural diagram of a blade body according to a first embodiment of the present invention; Figure 3 This is a structural schematic diagram of a first end of a blade body according to a first embodiment of the present invention, cut off by a cutting plane; Figure 4 This is a structural schematic diagram of the second end of the blade body of the first embodiment of the present invention cut by a cutting plane; Figure 5 This is a schematic structural diagram of an impeller assembly according to a second embodiment of the present invention; Figure 6 It is a front view of the impeller assembly of the second embodiment of the present invention; Figure 7 Schematic diagram of the inlet angle and outlet angle of the blade body at the first end surface of the first and second embodiments of the present invention; Figure 8 Schematic diagram of the inlet angle and outlet angle of the blade body at the second end surface of the first and second embodiments of the present invention; Figure 9 This is a structural diagram of the centrifugal fan of Example 3 of the present invention when its components are disassembled; Figure 10 This is a cross-sectional schematic diagram of the assembled components of the centrifugal fan according to the third embodiment of the present invention; Figure 11Schematic diagram of the internal airflow direction of the centrifugal fan in operation according to the third embodiment of the present invention; Figure 12 A side view of an air guide member according to a third embodiment of the present invention; Figure 13 The figure is a cross-sectional diagram of the assembled components of the centrifugal fan in the prior art.

[0025] Description of main reference numerals: 10. Blade body; 101. First end surface; 102. Second end surface; 103. Intersecting plane; 11. First air guide surface; 111. First arc segment; 112. Plane segment; 12. Second air guide surface; 121. Second arc segment; 122. Third arc segment; 13. First air guide line; 131. First arc segment; 132. Straight line segment; 14. Second air guide line; 141. Second arc segment; 142. Third arc segment; 143. Fourth arc segment; 144. Fifth arc segment; 15. Leading edge transition surface; 151. Leading edge arc line; 16. Trailing edge Transition surface; 161, trailing edge arc line; 17, center line; 20, impeller assembly; 21, mounting plate; 211, mounting surface; 22, diffuser channel; 23, hub; 30, volute; 31, mounting port; 32, air outlet; 33, air cavity; 331, annular cavity section; 34, first side plate; 35, second side plate; 36, enclosure; 40, air guide; 41, blocking section; 411, anti-leakage channel; 42, air guide channel; 43, air guide ring; 44, mounting section; 45, arc-shaped transition section; 50, drive motor; 51, drive shaft; 511, connecting end. DETAILED DESCRIPTION

[0026] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0027] In the present invention, terms such as "upper," "lower," "left," "right," "front," "back," "top," "bottom," "inner," "outer," "center," "vertical," "horizontal," "transverse," and "longitudinal" indicate positions or locations based on the positions or locations shown in the accompanying drawings. These terms are primarily intended to better describe the present invention and its embodiments and are not intended to limit the devices, elements, or components indicated to having a specific orientation, or to being constructed or operated in a specific orientation.

[0028] Furthermore, some of the above terms may be used to express other meanings besides indicating a position or location. For example, the term "on" may also be used to indicate a dependency or connection in certain circumstances. Those skilled in the art will understand the specific meanings of these terms in the present invention based on the specific circumstances.

[0029] Furthermore, the terms "installed," "disposed," "provided with," "connected," and "connected" should be interpreted broadly. For example, they can refer to fixed connections, removable connections, or integral structures; mechanical connections or electrical connections; direct connections or indirect connections through an intermediary; or internal communication between two devices, elements, or components. Those skilled in the art will understand the specific meanings of these terms in the present invention based on specific circumstances.

[0030] Furthermore, the terms "first," "second," and the like are primarily used to distinguish different devices, elements, or components (which may or may not be the same in type and configuration) and are not intended to indicate or imply the relative importance or quantity of the devices, elements, or components indicated. Unless otherwise specified, "plurality" means two or more.

[0031] The technical solution of the present invention will be further described below in conjunction with embodiments and drawings.

[0032] Example 1 See also Figure 1 and Figure 2 As shown, an embodiment of the present application provides a blade, including a blade body 10, and the two ends of the blade body 10 in the first direction are respectively a first end and a second end, the first end has a first end face 101, and the second end has a second end face 102, and a plane parallel to the first end face 101 and the second end face 102 is defined as a cutting plane 103.

[0033] Specifically, the blade body 10 includes a first wind guide surface 11 and a second wind guide surface 12 that are arranged to face away from each other. Figure 3 or Figure 4 A first wind guide line 13 is obtained by cutting the first wind guide surface 11 with a cutting plane 103. The first wind guide line 13 includes a first arc segment 131 and a straight line segment 132 that are connected to each other. Meanwhile, a second wind guide line 14 is obtained by cutting the second wind guide surface 12 with the cutting plane 103. The second wind guide line 14 includes at least two arc segments, and the curvature radii of the at least two arc segments are different.

[0034] It should be noted that, in the present application, the first direction is the height direction of the blade. The first wind guide surface 11 and the second wind guide surface 12 are two side surfaces of the blade body 10 in the thickness direction.

[0035] Based on this structure, when the blades of the present invention are used to generate and guide airflow, the airflow enters the diffuser channel 22 from the air inlet end formed between the two blades. Within the diffuser channel 22, the airflow is pressurized by the combined action of the first air guide surface 11 of the blade and the second air guide surface 12 of the adjacent blade. Simultaneously, guided by both air guide surfaces, the airflow is directed out of the air outlet end of the diffuser channel 22. Specifically, the airflow guidance process of the first air guide line 13 and the second air guide line 14 at a certain blade height will be described below.

[0036] When airflow enters the inlet end of the diffuser duct 22, the airflow direction at that end often exhibits significant directional deviations, presenting a chaotic state. A portion of the airflow first encounters the straight segment 132 of the first air guide 13, located near the inlet end. This straight segment 132, through its straight trajectory, quickly regularizes the chaotic airflow direction at the inlet end, allowing the airflow to enter the diffuser duct 22 in a stable and orderly manner. This effectively avoids localized high-speed impacts caused by the initial chaotic airflow direction, reduces the degree of turbulence upon entry, and thus minimizes energy loss caused by the initial turbulence.

[0037] When airflow flows along straight segment 132 to first curved segment 131 of first air guide 13, the curvature of first curved segment 131 aligns with the airflow direction directed by straight segment 132, smoothly receiving the airflow. When the airflow contacts first curved segment 131, the arc of the curved segment exerts a continuous force on the airflow, causing the airflow to change direction under the influence of this continuous force, achieving a gradual transition in direction. This reduces separation and turbulence caused by sudden changes in the airflow direction, guiding the airflow to flow smoothly along its curved path within diffuser channel 22.

[0038] At the same time, part of the airflow at the air inlet end will also come into contact with the arc segment of the second air guide line 14. The arc segment uses its arc trajectory to preliminarily guide the airflow to change its flow direction, thereby achieving preliminary rectification and guidance of the airflow at the air inlet end. As the airflow advances in the diffuser channel 22, since the second air guide line 14 is composed of at least two arc segments with different curvature radii, it can be understood that the arc segment with a smaller curvature can exert a stronger constraint and guiding force on the airflow through a compact curve trajectory, thereby controlling the flow trajectory of the airflow, and accelerating and compressing the airflow at the air inlet end according to a predetermined path in the diffuser channel 22. The arc segment with a larger curvature can guide the airflow at a relatively gentle angle, so that the airflow gradually adjusts its direction and speed in a relatively spacious space. The present application combines arc segments with different curvature radii into the second air guide line 14, which can coordinately adjust the airflow speed and pressure.

[0039] More specifically, this embodiment is illustrated by taking the second air guide line 14 as including two arc segments, the two arc segments are the second arc segment 141 and the third arc segment 142, wherein the curvature radius of the second arc segment 141 is smaller than the curvature radius of the third arc segment 142, and the second arc segment 141 is arranged at the air inlet end of the blade.

[0040] It should be noted that the geometric characteristics of the arc segment with a larger curvature radius (such as the third arc segment 142) are characterized by a flatter curve. If it is used alone for the entire air guide line, in order to meet the required profile length for airflow guidance, the blade's physical structure needs to extend further radially, thereby increasing the radial length of the blade.

[0041] The arc segment with a smaller curvature radius (such as the second arc segment 141) has a steeper curve, and the length of the profile required to guide the airflow to change the same angle is shorter than the length of the profile with a large curvature radius. If it is used alone for the entire wind guide line, although the blade width can be reduced, the steeper curve curvature can easily cause the airflow speed to change sharply during the flow process. The airflow in the boundary layer cannot continue to flow along the blade surface, and separation will occur, forming a large number of vortices.

[0042] Therefore, this application utilizes a small curvature radius arc segment (second arc segment 141) at the air inlet, enabling rapid airflow direction change and reducing the need for radial extension. A large curvature radius arc segment (third arc segment 142) is employed at the air outlet. While this requires a certain radial length, the large curvature arc segment ensures smooth airflow discharge, as the airflow has already undergone major deflection. By combining arc segments with various curvature radii, the increased radial length of the blade, which would result from the full use of a large curvature radius, is avoided, and airflow separation losses are also reduced.

[0043] Thus, the coordinated cooperation between the first air guide surface 11 and the second air guide surface 12 can effectively suppress airflow separation, reduce the generation of vortices and pulsations, and when the blade of the present application is applied to a fan, it can reduce the operating noise of the fan. At the same time, by reducing airflow energy loss, it can improve the aerodynamic efficiency of the fan and reduce energy consumption per unit air volume.

[0044] As an optional implementation, see Figure 3 , the connecting point of the first arc segment 131 and the straight line segment 132 is defined as point A, and the tangent line L1 of the first arc segment 131 at point A coincides with the straight line where the straight line segment 132 is located.

[0045] Thus, when airflow enters the air inlet end of the diffuser channel 22, it first encounters the straight segment 132 of the first air guide 13. With its straight trajectory, straight segment 132 initially regularizes the turbulent airflow, allowing it to flow relatively smoothly toward point A. Because the tangent line L1 of the first arc segment 131 at point A coincides with the line along which straight segment 132 lies, upon reaching point A, the airflow's direction of flow is the same as the direction of the first arc segment 131 at point A. This allows the airflow to transition naturally and smoothly from straight segment 132 to the first arc segment 131 without changing its trajectory. It should be noted that if there is an angle difference between the straight segment 132 and the first arc segment 131, the airflow will produce greater impact and turbulence due to the sudden change in direction when passing through this position, which will lead to increased energy loss and may even cause airflow separation.

[0046] Therefore, by aligning the tangent line L1 of the first arc segment 131 at point A with the line along which the straight line segment 132 lies, the present application effectively avoids sudden changes in the airflow direction during the transition from the straight line segment 132 to the first arc segment 131. The airflow then smoothly continues to flow along the curved trajectory of the first arc segment 131. The first arc segment 131, through its curved trajectory, exerts a continuous force on the airflow, guiding it to change direction without excessive loss of kinetic energy, allowing it to continue its stable flow within the diffuser channel 22. Furthermore, the blades' stability and reliability in the process of generating and guiding airflow are ensured. Under actual operating conditions, airflow parameters such as velocity and pressure are constantly changing. The angular connection between the straight segment 132 and the first arc segment 131 allows the blades to consistently and efficiently guide airflow under various complex airflow conditions, reducing the additional forces on the blades caused by airflow fluctuations and extending their service life.

[0047] As an optional embodiment, the blade body 10 includes a first section and a second section that are connected to each other. Specifically, a flat section 112 is provided on one side of the first section, and a first curved section 111 is provided on one side of the second section. The first curved section 111 and the flat section 112 are connected to form the first wind-guiding surface 11. The straight line segment 132 is obtained by cutting the flat section 112 using the cutting plane 103, and the first curved section 111 is obtained by cutting the first curved section 111 using the cutting plane 103.

[0048] Based on this structure, when in use, after the airflow enters from the air inlet end of the diffuser channel 22, it first contacts the planar section 112 of the first section. The planar section 112 can generate friction and geometric constraints by contacting the airflow with its flat surface, thereby preliminarily regularizing the chaotic airflow direction. In addition, its straight structure can effectively prevent the airflow from generating local high-speed impacts due to collisions, so that the airflow flows in a relatively stable and orderly state toward the junction of the planar section 112 and the first arc section 111. As the airflow flows along the flat section 112 to the connection position with the first curved section 111, the curvature of the first curved section 111 is the same as the airflow direction derived from the flat section 112. When the airflow reaches the connection point, the first curved section 111, with its continuous curved surface, can achieve a seamless transition with the flat section 112. The airflow can continue to flow naturally along the curved trajectory of the first curved section 111 without significantly changing its own movement trend. During this process, the curved surface structure of the first curved section 111 will exert a continuous force on the airflow, guiding the airflow to change direction without losing too much kinetic energy of the airflow, achieving smooth turning of the airflow within the diffuser channel 22, effectively avoiding turbulence and separation caused by sudden changes in the airflow direction, and reducing energy loss. Thus, the first flat section 112 and the second curved section 111 work together: the flat section 112 provides preliminary airflow rectification, while the first curved section 111 provides refined guidance and direction adjustment. In actual operating conditions, this segmented structure ensures continuous and stable airflow guidance, reducing the additional stress on the blades caused by airflow fluctuations and improving blade durability.

[0049] In addition, at least one arc segment is provided on the side of the first section facing away from the plane section 112 and the side of the second section facing away from the first arc segment 111, and these arc segments are connected in sequence to form the second wind guide surface 12, and two adjacent arc segments are connected at the same angle.

[0050] As an optional implementation, along the first direction, the curvature radii of the first arc segments 131 obtained by intercepting the first arc segment 111 by each intercepting plane 103 are all the same.

[0051] Based on this structure, when the airflow flows in the first direction along the diffuser channel 22, since the curvature radius of the first arc segment 131 at each height position is consistent, the guiding force and flow constraint on the airflow in the cross section perpendicular to the blade height direction tend to be stable.

[0052] After entering the diffuser 22, the airflow is initially regularized by the first planar segment 112 before entering the second curved segment 111. During ascent or descent along the first direction, the airflow is guided by the first curved segment 131 with the same curvature regardless of the blade's height. This consistency ensures the continuity of the airflow's vertical trajectory within the diffuser 22. For example, after the airflow smoothly turns along the first curved segment 131 at a certain height, it will continue to change direction in the same manner and to the same extent at higher or lower locations, preventing sudden changes in airflow direction or additional disturbances due to altitude changes. Thus, the first arc segments 131 having the same curvature radius can effectively reduce the unevenness of the airflow along the height direction within the diffuser channel 22. It should be noted that if the curvature radius of the first arc segments 131 at different heights were different, the guiding force and flow resistance experienced by the airflow would vary when passing through different heights, potentially causing local vortices or airflow separation within the diffuser channel 22.

[0053] However, the present application maintains a consistent radius of curvature of the first arc segment 131 at each height, so that the airflow can flow smoothly and evenly throughout the entire blade height range, which helps to improve the overall stability and smoothness of the airflow.

[0054] As an optional implementation, see again Figure 2 , define the straight line direction where the straight line segment 132 is located as the second direction. Figure 3 and Figure 4 ,in, Figure 3 The cutting plane 103 coincides with the first end face 101, and the cutting plane 103 cuts off the blade profile at the first end. Figure 4 The cutting plane 103 coincides with the second end face 102, and the cutting plane 103 cuts off the blade at the second end to obtain the blade profile. Along the first direction, the width of the first segment in the second direction gradually decreases.

[0055] Based on this structure, as airflow enters diffuser channel 22, it first encounters planar section 112 of the first section. Since airflow at the inlet typically experiences uneven velocity and turbulent direction, the structure of the first section, whose width gradually decreases along the first and second directions, enables preliminary diversion and adjustment of the airflow. When airflow enters from the inlet, the wider blade root receives more airflow. As the airflow flows along the first direction, the width of the first section gradually narrows, constraining the airflow in the width direction and promoting a gradual uniformity of airflow velocity, thereby avoiding localized excessively high or low airflow velocities. During use, as the airflow flows along the flat section 112 of the first section to the first curved section 111 of the second section, the width of the second section gradually decreases, which can also effectively reduce the risk of boundary layer separation of the airflow on the blade surface. When the airflow flows over the surface of an object, the boundary layer is prone to separation at the point where the shape suddenly changes, generating vortices and increasing energy loss. The structure of the first section with a gradual width change provides a smooth transition space for the airflow, allowing the airflow to better fit the flow of the blade surface. The trend of gradually narrowing the width will produce a pressure gradient related to the flow direction for the airflow. This pressure gradient helps to push the airflow to overcome surface friction, maintain the stability of the boundary layer, reduce the energy loss caused by boundary layer separation, and improve the flow efficiency of the airflow in the diffuser channel 22. In addition, when the multiple blades of the present application are installed on the impeller, the first end of the blade is installed on the mounting plate 21 of the impeller, and the second end is cantilevered. This will cause the second end of the blade to be subjected to greater centrifugal force and vibration load during the high-speed rotation of the impeller. The present application can reduce the weight of the blade at the second end by gradually narrowing the width of the first section of the blade from the first end to the second end of the blade. When the impeller rotates at high speed, the second end of the blade, which originally has a larger mass, will generate a strong centrifugal pull, causing a large load on the root of the blade and the entire impeller structure. After reducing the weight of the second end, the centrifugal force is significantly reduced, which effectively reduces the risk of deformation of the blade due to centrifugal force, avoids fatigue damage or fracture caused by excessive stress on the root of the blade, and thus enhances the reliability and safety of the blade structure.

[0056] As an optional implementation, see Figure 3 The second air guide surface 12 includes three arcuate segments: a second arcuate segment 121, a third arcuate segment 122, and a fourth arcuate segment, which are connected in sequence. The second arcuate segment 121 is cut using the cutting plane 103 to obtain the second arcuate segment 141, the third arcuate segment 122 is cut using the cutting plane 103 to obtain the third arcuate segment 142, and the fourth arcuate segment 143 is cut using the cutting plane 103 to obtain the fourth arcuate segment. Furthermore, the radius of curvature of the second arcuate segment 141 is smaller than the radius of curvature of the third arcuate segment 142, and the radius of curvature of the third arcuate segment 142 is larger than the radius of curvature of the fourth arcuate segment 143.

[0057] Based on this structure, when airflow enters the inlet end of the diffuser duct 22, a portion of it first encounters the second curved segment 141 near the inlet end. Because airflow at the inlet end typically exhibits high turbulence and significant velocity fluctuations, the smaller radius of curvature of the second curved segment 141 creates a compact curved trajectory, exerting a strong restraining and guiding force on the airflow, rapidly changing its initial direction and initially directing the turbulent airflow into the diffuser duct 22. In other words, the smaller radius of curvature forces the airflow to accelerate as it passes through this segment, not only helping to dissipate vortices at the inlet end but also allowing the airflow to quickly achieve a relatively stable flow direction. As the airflow continues to flow through the diffuser duct 22, it enters the area of ​​action of the third arc segment 142. The larger radius of curvature of the third arc segment 142 provides a relatively gentle curve and ample flow space. Here, the high velocity achieved by the airflow in the second arc segment 141 is adjusted. The third arc segment 142, with its gently curved surface, relatively weakens the force exerted on the airflow, allowing the airflow to further adjust its direction and velocity in a relatively stable state. When the airflow reaches fourth arc segment 143, its radius of curvature decreases again, allowing it to provide a final, precise guide and acceleration. At this point, fourth arc segment 143, thanks to its compact curved structure, imposes a strong constraint on the airflow, accelerating it along a predetermined path within diffuser duct 22 and exiting the outlet of diffuser duct 22 at a specific speed and direction.

[0058] As a result, the three arc segments of the second air-guiding surface 12 cooperate with each other. The second arc segment 141 quickly rectifies and initially accelerates the turbulent airflow at the air inlet; the third arc segment 142 further adjusts the airflow speed and direction and balances the pressure; and the fourth arc segment 143 achieves precise guidance and final acceleration of the airflow. By differentiating the curvature radius, the three segments finely control the speed, direction, and pressure of the airflow at different stages, effectively suppressing the airflow separation phenomenon, reducing the generation of vortices and pulsations, and reducing the operating noise of the fan. At the same time, this precise airflow guidance method minimizes airflow energy loss, significantly improves the aerodynamic efficiency of the fan, and reduces energy consumption per unit air volume.

[0059] In addition, the second wind guide surface 12 may also include four arc segments, see Figure 4 Correspondingly, the second wind guide line 14 includes four arc segments, namely the second arc segment 141, the third arc segment 142, the fourth arc segment 143 and the fifth arc segment 144, and the curvature radius of the third arc segment 142 is greater than the curvature radius of the second arc segment 141, the curvature radius of the fourth arc segment 143 is greater than the curvature radius of the third arc segment 142, and the curvature radius of the fifth arc segment 144 is smaller than the curvature radius of the fourth arc segment 143.

[0060] It can be understood that each arc segment can exert a force of specific direction and intensity on the airflow based on its own unique curvature. By setting more arc segments, the arc segments can gradually change the direction of the airflow at a shorter distance and finer scale, avoiding large energy loss and eddy currents caused by sudden changes in direction of the airflow, thereby achieving more precise and complex control of the airflow and significantly improving the blade's guidance effect on the airflow.

[0061] As an optional implementation, see Figure 3 as well as Figure 4 Along the first direction, the curvature radius of the second arc segment 141 obtained by the intercepting plane 103 intercepting the second arc surface segment 121 is the same, the curvature radius of the third arc segment 142 obtained by the intercepting plane 103 intercepting the third arc surface segment 122 is the same, and the curvature radius of the fourth arc segment 143 obtained by the intercepting plane 103 intercepting the fourth arc surface segment is the same.

[0062] Based on this structure, when the airflow enters the diffuser channel 22 and contacts the second arc segment 121, since all the second arc segments 141 have the same radius of curvature, the airflow is subject to the same guiding force and degree of constraint at each cross section perpendicular to the blade height direction. This prevents the airflow from experiencing a sudden change in guiding force due to height changes when rising or falling in the first direction. For example, at a certain height, after the airflow completes initial direction adjustment and acceleration through the second arc segment 141, it will continue to change direction and speed to the same degree and in the same manner at higher or lower positions, ensuring that the airflow maintains a stable and coherent flow trajectory throughout the entire blade height range, reducing airflow turbulence, separation, or vortex phenomena caused by uneven guidance, and greatly improving the stability of the airflow. Similarly, when the airflow reaches the third arc segment 122 or the fourth arc segment, it can also maintain a stable and coherent flow trajectory at different heights.

[0063] Therefore, the stable airflow guidance characteristics can effectively reduce the fatigue damage of the airflow to the blades. It should be noted that if the curvature radius of the arc segments at different height positions is different, the force of the airflow on the blade surface will fluctuate with the height, and long-term action will easily cause fatigue cracks in the blades. However, the curvature radius of the corresponding arc segments of each arc surface segment remains consistent, making the force of the airflow on the blade surface more evenly distributed, reducing the local stress concentration caused by uneven force, reducing the risk of fatigue damage to the blades, and thus extending the service life of the blades.

[0064] Furthermore, the tangent directions of the two connected arc segments at the connection point are the same, enabling seamless airflow transition. When air flows from one arc segment to another along the second air guide 14, the consistent tangent directions at the connection point allow the airflow to smoothly transition from one arc segment to the next without changing its own motion trend. This effectively avoids airflow shock and turbulence caused by sudden changes in direction, reducing the risk of airflow separation.

[0065] As an optional embodiment, the inlet angle of the blade body 10 is α, and the value range of α is 25°<α<49°; at the same time, the outlet angle of the blade body 10 is β, and the value range of β is 90°<β<140°.

[0066] Specifically, the blade body 10 also includes a leading edge transition surface 15 and a trailing edge transition surface 16, wherein the air inlet end of the first air guide surface 11 and the air inlet end of the second air guide surface 12 are connected by the leading edge transition surface 15, and the air outlet end of the first air guide surface 11 and the air outlet end of the second air guide surface 12 are connected by the trailing edge transition surface 16, and both the leading edge transition surface 15 and the trailing edge transition surface 16 are arc-shaped guiding surfaces.

[0067] When airflow enters from the air inlet, the leading edge transition surface 15, with its smooth curved surface, effectively guides the airflow smoothly into the diffuser duct 22, preventing the airflow from generating strong impacts and vortices due to sudden turns at the air inlet. Compared to the planar leading edge transition surface 15, the curved guide surface is less likely to form sharp corners at the air inlet, reducing energy loss during airflow entry and allowing the airflow to contact the first and second air guide surfaces 11, 12 in a relatively orderly manner. After the airflow completes its flow within the diffuser duct 22, the curved structure of the trailing edge transition surface 16 ensures that the airflow can be smoothly discharged from the diffuser duct 22.

[0068] The cutting plane 103 cuts the leading edge transition surface 15 to obtain the leading edge arc line 151, and the cutting plane 103 cuts the trailing edge transition surface 16 to obtain the trailing edge arc line 161. Figure 7 A centerline 17 is defined between the first air guide line 13 and the second air guide line 14. It should be noted that centerline 17 is a curve and divides the blade body 10 into two equal sections along the thickness direction. The point where the leading edge arc line 151 meets centerline 17 is defined as point B, and the tangent to centerline 17 at point B is defined as L2. A circle is constructed with the rotation center of the mounting plate 21 as the center and the distance from point B to the rotation center of the mounting plate 21 as the radius. The tangent to this circle at point B is defined as L3. The angle between L2 and L3 is the blade inlet angle α.

[0069] Similarly, the connection point of the trailing edge arc line 161 and the center line 17 is defined as point C, and the tangent of the center line 17 at point C is L4. A circle is drawn with the rotation center of the mounting plate 21 as the center and the distance from point C to the rotation center of the mounting plate 21 as the radius. The tangent of the circle at point C is L5, and the angle between L4 and L5 is the outlet angle β of the blade.

[0070] If α is too small (≤25°), the angle between the airflow's inlet direction and the tangent to the blade's centerline 17 is too steep, easily creating a strong impact with the air guide surface, generating vortices and energy loss. If α is too large (≥49°), the airflow is prone to boundary layer separation on both sides of the blade body 1, resulting in airflow separation losses. Therefore, when the blade's inlet angle α is set between 25° and 49°, the curved transition surface of the blade's leading edge matches the inlet angle, guiding the airflow smoothly into the diffuser duct 22, reducing impact losses and improving intake efficiency.

[0071] If β ≤ 90°, the blades are backward-facing, and the circumferential component of the absolute velocity at the airflow outlet is low, reducing pressure conversion efficiency and lowering the fan's total pressure, making it difficult to meet high pressure requirements. If β ≥ 140°, the blades are tilted too far forward, and the width of diffuser channel 22 decreases at the outlet. Diffuser channel 22 has a small inlet width, then gradually increases in width, and then decreases again. The relative velocity of the airflow first decreases and then increases, easily causing separation losses and reducing impeller efficiency. Therefore, when the blade outlet angle β is set between 90° and 140°, the circumferential component of the absolute velocity at the outlet is low, while the radial component is high. This allows the gradual expansion of diffuser channel 22 to more effectively convert the airflow's kinetic energy into pressure energy. The airflow can be discharged from diffuser channel 22 at an appropriate speed and direction, ensuring that the airflow's kinetic energy is fully utilized while avoiding airflow turbulence and energy loss caused by improper angles.

[0072] In addition, reasonable blade inlet and outlet angles can optimize the pressure distribution on the blade surface, reduce the impact of airflow on the blade trailing edge, reduce the vibration and noise caused by uneven force on the blade, extend the service life of the blade, and improve the stability and reliability of equipment operation.

[0073] Thus, this embodiment optimizes the entire process from airflow entry to exit by utilizing the curved structures of the leading edge transition surface 15 and the trailing edge transition surface 16, as well as limiting the blade inlet and outlet angles within a certain range. This reduces energy loss during airflow entry and exit from the diffuser 22, and inhibits the generation of vortices and airflow separation. Furthermore, the stable airflow reduces vibration and noise during operation, lowering maintenance costs and enabling more efficient and stable operation.

[0074] It should be added that each cutting plane 103 obtains a cross-sectional profile after cutting the entire blade, and the cross-sectional profile is formed by connecting the first wind guide line 13, the leading edge arc line 151, the second wind guide line 14 and the trailing edge arc line 161 in sequence to form a closed profile.

[0075] As an optional embodiment, along the first direction, the inlet angle α on each intercepting plane 103 gradually decreases, and the outlet angle β gradually increases.

[0076] See Figure 7 , the blade body 10 is at a height position of the first end surface 101, its inlet angle is α1, and its outlet angle is β1; Figure 8 , at the height position of the second end face 102, the blade body 10 has an inlet angle of α2 and an outlet angle of β2, and α1 is greater than α2, β1 is smaller than β2, and this change is gradual in the first direction. For example, a cutting plane 103 can be set between the first end face 101 and the second end face 102, and the distances between the cutting plane 103 and the first end face 101 and the second end face 102 are the same. Then the inlet angle on the cutting plane 103 is α3, and the outlet angle is β3. At this time, α1, α3, and α2 can gradually decrease at equidistant angles. Similarly, β1, β3, and α2 can gradually increase at equidistant angles, so that the angle change is more uniform and gentle.

[0077] Among them, as the airflow rises along the height direction of the blade, the inlet angle gradually decreases, which can provide a more fitting introduction angle for the airflow at the air inlet end of the blade. Specifically, during the rising process, the airflow can gradually adapt to the changes in the circumferential speed caused by the rotation of the blade, and adjust the entry posture according to the changes in the inlet angle on the intercepting plane 103 at different heights, so as to avoid excessive impact or poor introduction of the airflow at a certain height due to the fixed inlet angle. For example, at a lower position, a larger inlet angle can better adapt to the lower circumferential speed here, allowing the airflow to smoothly transition from axial to radial flow, reducing the impact loss at the initial entry; and at a higher position, appropriately reducing the inlet angle can match the significantly increased circumferential speed here, so that the airflow enters the diffuser channel 22 with a posture that is more in line with the blade angle, avoiding vortices caused by mismatched velocity directions, and ensuring that the airflow can maintain an orderly flow state during the entry stage.

[0078] During the process of airflow flowing along the height direction of the blade, as the airflow rises along the height direction of the blade, the outlet angle gradually increases, which provides a looser outlet space for the airflow at the air outlet end of the blade. At this time, the airflow can gradually adjust its own speed and direction during the upward process, and change the flow trend according to the change of the outlet angle on the intercepting plane 103 at different heights, avoiding the situation where the airflow is over-constrained or over-dispersed at a certain height due to the fixed outlet angle. For example, at a lower position, a smaller outlet angle allows the airflow to quickly regularize its direction and moderately accelerate; at a higher position, appropriately increasing the outlet angle can improve the blade's ability to work on the airflow, allowing the airflow to be exported more smoothly. It should be noted that the traditional blades with fixed inlet and outlet angles may produce large adverse pressure gradients or airflow diffusion losses at certain height positions due to the mismatch between the inlet and outlet angles and the actual needs of the airflow. However, the present application gradually reduces the inlet angle and gradually increases the outlet angle, so that the flow of the airflow at each height position can be adapted to the inlet and outlet angles. At the lower position of the blade, although the smaller outlet angle will impose certain constraints on the airflow, this constraint helps to quickly sort out the airflow, and because the airflow speed and energy have not yet fully developed, the energy loss generated is relatively small; as the airflow rises, the outlet angle increases, which just meets the needs of the change in speed and direction of the airflow during the flow process, reduces the airflow deceleration and boundary layer separation caused by the adverse pressure gradient, and also avoids the excessive dispersion of the airflow caused by an excessively large outlet angle.

[0079] In this way, the airflow can maintain a relatively stable energy state throughout the entire blade height range, converting more kinetic energy into the pressure energy required by the equipment, greatly improving the aerodynamic efficiency of the equipment and reducing energy consumption per unit air volume. In addition, since the inlet angle α on each intercepting plane 103 gradually decreases and the outlet angle β gradually increases in the first direction, and the shapes and angles of the first air guide line 13 and the second air guide line 14 differ on the intercepting planes 103 at different heights of the blade, when observed from a three-dimensional perspective, the changes in the cross-sectional shapes at different heights cause the blade as a whole to appear twisted. In other words, the blade of the present application is a three-dimensional twisted blade.

[0080] Example 2 See Figure 5 and Figure 6 This embodiment discloses an impeller assembly 20, which includes a mounting plate 21 and multiple blades of embodiment 1, wherein the mounting plate 21 has a central axis and a mounting surface 211, and multiple blade bodies 10 are arranged at equal intervals along the circumferential direction around the central axis and are mounted on the mounting surface 211 through the first end.

[0081] Based on this structure, when using the impeller assembly 20 of the present invention, during assembly, multiple blade bodies 10 are arranged at equal intervals along the circumferential direction around the central axis. In this application, the central axis of the mounting plate 21 extends along the first direction. The blades are mounted on the mounting surface 211 via their first ends, and the first ends and the mounting surface 211 can be fixed by welding, bolting, or mortise and tenon joints to ensure that the blades do not loosen during high-speed rotation.

[0082] As a result, the blades can be firmly attached to the mounting plate 21 and rotate at high speed driven by the mounting plate 21 to perform work and guide the airflow; and the blades are evenly distributed, which can balance the force during rotation.

[0083] Among them, see Figure 7 and Figure 8 The outlet angle β of the blade body 10 at the height of the first end face 101 and the second end face 102 is greater than 90°, and the outlet angle β of the blade body 10 at different heights between the first end face 101 and the second end face 102 is also greater than 90°. The outlet direction of the airflow is toward the rotation direction of the impeller assembly 20, and the blade is a forward-facing three-dimensional twisted blade.

[0084] It should be noted that the first wind guiding surface 11 in the present application is a windward surface, and the second wind guiding surface 12 is a wind suction surface.

[0085] When the impeller assembly 20 begins operation, turbulent airflow rushes into the inlet of the diffuser duct 22 formed between the blades. Because the straight segment 132 of the first air-guiding surface 11 of the blade is close to the inlet, the airflow first encounters this segment 132. This segment, with its straight trajectory, quickly regularizes the airflow, allowing it to enter the diffuser duct 22 in a stable state. Simultaneously, a portion of the airflow at the inlet contacts the small-radius curved segment of the second air-guiding surface 12, which provides a preliminary, rapid, and steeply directed redirection of the airflow. As the impeller continues to rotate, airflow continues to flow within the diffuser channel 22. At this point, the curved section of the first air-guiding surface 11 and the arc segment with a large radius of curvature of the second air-guiding surface 12 come into play. The curved section of the first air-guiding surface 11 smoothly connects with the straight section 132, and its curvature matches the airflow direction derived from the straight section 132, further guiding the airflow to change direction within the channel. The arc segment with a large radius of curvature of the second air-guiding surface 12 utilizes a gentle arc to adjust the airflow's velocity and pressure, preventing separation due to excessive velocity or sudden changes in direction. When the airflow reaches the outlet of diffuser duct 22, because the blade outlet angle β is greater than 90°, the airflow not only has tangential velocity but also acquires an additional radial velocity component when leaving diffuser duct 22. During the rotation of impeller assembly 20, the forward blade outlet angle causes the airflow to deviate from the radial direction at a larger angle, increasing the circumferential velocity of the airflow and significantly improving the blade outlet pressure.

[0086] Finally, the curved structure of the blade trailing edge transition surface 16 and the specific blade outlet angle ensure that airflow is directed at the appropriate speed and direction. Multiple blades are evenly spaced around the central axis, and the mounting plate 21 drives the blades to rotate at high speed around the central axis, continuously drawing in external airflow and performing work, achieving efficient airflow processing and energy conversion. Ultimately, the processed airflow is delivered to the target location, meeting the equipment's operational requirements.

[0087] The blades are capable of performing work and guiding the airflow within the diffuser channel 22. The blade structure, including the combination of the planar segment 112 and the first curved segment 111 of the first air-guiding surface 11, the coordinated use of multiple curved segments with different curvature radii of the second air-guiding surface 12, and the curved guiding surfaces of the leading and trailing edge transition surfaces 16, finely regulates the airflow from multiple dimensions. During the airflow guidance process, the blade structure effectively suppresses airflow separation, significantly reduces the generation of vortices, and fundamentally reduces energy loss caused by airflow turbulence. Due to the blade structure's effective suppression of airflow separation and vortices, the vibration caused by airflow instability during operation of the impeller assembly 20 is significantly reduced.

[0088] The specific structural details of the blade and its guiding mechanism for the airflow have been described in detail in Example 1, including the design principles of the curvature of each arc segment, the influence of the outlet angle on the airflow, etc., and will not be repeated here.

[0089] It should be noted that in this embodiment, the first end of the blade is mounted on the mounting plate 21, while the second end of the blade is away from the mounting plate 21 and is in a cantilever state, and there is no need to set up an additional intermediate support structure to maintain the blade shape and stability. Compared with the traditional two-end support or multi-support blade structure, the present application can reduce the metal material required for the support components, including connectors, support beams and other components, thereby reducing the overall weight of the impeller assembly 20. In this way, when the impeller is working, its rotational inertia is reduced, and the energy required to overcome inertia during acceleration, deceleration and variable operating conditions of the impeller assembly 20 is reduced. Therefore, the impeller assembly 20 can reach the rated speed from a stationary state more quickly, shortening the startup time of the equipment and improving the response efficiency of the equipment.

[0090] Example 3 See Figure 9 and Figure 10This embodiment discloses a centrifugal fan, which includes a volute 30 and an impeller assembly 20 as described in the second embodiment above. The impeller assembly 20 is installed in the volute 30.

[0091] On the basis of this structure, when the centrifugal fan of the present application is used, after the centrifugal fan is started, the outside gas enters the inside of the fan from the preset air inlet on the volute 30. At this time, the impeller assembly 20 rotates at high speed under the drive of the motor, and a negative pressure area is formed at the air inlet inside the volute 30, and the outside gas is sucked in under the action of the pressure difference. The gas entering the fan first contacts the high-speed rotating impeller assembly 20. The blades in the impeller assembly 20 are arranged at equal intervals around the circumference of the central axis, and the first end of the blade is fixed to the mounting plate 21 and the second end is cantilevered. During the rotation of the impeller, the gas flows along the channel formed by the first air guide surface 11 and the second air guide surface 12 of the blade. The unique structure of the blade, such as the combination of the straight segment 132 and the arc segment of the first air guide line 13, the coordination of multiple arc segments with different curvature radii of the second air guide line 14, and the specific blade outlet angle design, perform work and guide the gas. During the airflow guidance process, the straight section 132 at the air inlet end quickly regularizes the turbulent airflow, and the arc segment with a small curvature radius performs a preliminary deflection on the airflow; the combination of arc segments with different curvature radii in the channel makes the airflow velocity and pressure distribution more reasonable, avoiding separation caused by sudden changes in direction or speed; the trailing edge arc line 161 at the air outlet end and the specific blade outlet angle ensure that the airflow is discharged in a stable state. As the blades continue to rotate, the gas is thrown from the center of the impeller to the edge of the impeller under the action of centrifugal force, gaining kinetic energy. The accelerated gas enters the annular cavity section 331 between the volute 30 and the impeller assembly 20. Due to the restriction of the volute 30, the gas flow space gradually expands. According to Bernoulli's principle, the gas flow rate decreases and the pressure increases, realizing the gas pressurization process. Finally, the pressurized gas is discharged from the outlet of the volute 30.

[0092] As a result, during the airflow guidance process, the centrifugal fan's blade structure effectively suppresses airflow separation, significantly reducing the generation of eddies, and fundamentally reducing energy loss caused by airflow turbulence. Because the blade structure effectively suppresses airflow separation and eddies, the vibration generated by unstable airflow during operation of the impeller assembly 20 is significantly reduced, significantly reducing fan noise.

[0093] As an optional embodiment, the centrifugal fan further includes an air guide 40. The volute 30 has an installation opening 31, an air outlet 32, and an air cavity 33. Specifically, the air guide 40 is installed in the installation opening 31, and the impeller assembly 20 is installed in the air cavity 33. The air guide 40 and the impeller assembly 20 are coaxially arranged. The air guide 40 is provided with an air guide channel 42. The air guide channel 42 is connected to the air cavity 33 and guides the air flow into the air cavity 33. The air outlet 32 ​​is connected to the air cavity 33 and guides the air flow out of the air cavity 33. Figure 10 and Figure 12 A blocking section 41 is provided on the side of the air guide 40 facing the impeller assembly 20 , and the blocking section 41 is spaced apart from the second end of the blade body 10 to form an anti-leakage channel 411 .

[0094] Based on this structure, when the centrifugal fan starts operating, the external airflow first reaches the mounting opening 31 of the volute 30 and enters the air guide channel 42 of the air guide member 40. The shape and angle of the air guide channel 42 can initially organize and guide the turbulent initial airflow, allowing the airflow to flow relatively smoothly and orderly toward the air cavity 33. Because the air guide member 40 is coaxially arranged with the impeller assembly 20, the airflow adjusted by the air guide channel 42 can be accurately aligned with the air inlet area of ​​the impeller assembly 20 and smoothly enter the air cavity 33. The airflow entering the wind cavity 33 meets the high-speed rotating impeller assembly 20, is accelerated by the blades and is thrown to the edge of the impeller. Subsequently, the airflow completes the expansion process in the annular cavity section 331 between the volute 30 and the impeller assembly 20. In the process of the airflow flowing from the impeller assembly 20 to the air outlet 32, the anti-leakage channel 411 formed by the blocking section 41 of the air guide 40 facing the side of the impeller assembly 20 and the second end of the blade body 10 begins to play a role. The anti-leakage channel 411 limits the backflow path of the airflow, ensuring that the airflow can only be discharged from the air outlet 32 ​​in a predetermined direction, thereby avoiding the disordered flow of the airflow inside the fan. Finally, the airflow that has been expanded and guided is discharged from the air outlet 32 ​​and transported to the target position, completing the entire gas delivery process.

[0095] Among them, see Figure 13 In the centrifugal fan of the related art shown, the air guide 40 and the impeller assembly 20 are axially spaced apart, forming a mounting gap. The first and second ends of the blades in the impeller assembly 20 are connected to the first and second end mounting plates, respectively. As the fan starts and the impeller assembly 20 rotates, the air guide channel 42 within the air guide 40 forms a region a with a negative pressure and a minimum pressure value, continuously drawing in external air. Region b is formed between the two blades and between the first and second end mounting plates. When the impeller assembly 20 rotates at high speed, the blades exert centrifugal force on the gas in region b, resulting in a positive pressure in region b. The annular region between the volute 30 and the impeller assembly 20 is region c. As the gas flows from region b to region c, the spatial structure of region c is wider than that of region b, so the flow space suddenly increases after entering region c. According to the principles of fluid mechanics, as the gas flow rate decreases, its kinetic energy gradually converts into pressure energy. This region c is positively pressurized and has the highest pressure value.

[0096] Due to the directional flow of the airflow, the radial ends of the installation gap formed axially between the air guide 40 and the impeller assembly 20 have a pressure value at one end close to the pressure value of area a, and a pressure value at the other end close to the pressure value of area c, that is, there is a large pressure difference between the two ends. At this time, the airflow will flow from the high-pressure end to the low-pressure end, that is, the airflow in area c will leak back from the gap, and the pressure difference between area a and area c is too large, resulting in a large flow rate of the leakage airflow. The leakage airflow is perpendicular to the main airflow direction in area a, which seriously interferes with the flow of the main airflow and affects the air intake state and working efficiency of the impeller.

[0097] See Figure 9 and Figure 10 In this application, a blocking section 41 is provided at the axial end of the air guide 40, so that the blade is mounted on the mounting plate 21 only by the first end of the blade body 10, and the second end of the blade body 10 and the blocking section 41 of the air guide 40 are spaced apart in the axial direction to form an anti-leakage channel 411. Figure 11 At this point, the air guide passage 42 within the air guide member 40 remains at negative pressure, while the area b formed between the two blades and the mounting plate 21 is at positive pressure. The area c formed between the volute 30 and the impeller assembly 20 is at positive pressure and has the highest pressure value. It is important to note that since there is no second end mounting plate between area b and the anti-leakage passage 411, communication between area b and the anti-leakage passage 411 is possible.

[0098] At this point, the pressure at one radial end of leak prevention channel 411 is close to that of region b, while the pressure at the other is close to that of region c. Because both regions b and c are at positive pressure and there is a small pressure differential between them, the radial pressure differential at leak prevention channel 411 is small, reducing the amount of air leaking back through the gap. Furthermore, because the amount of air leakage is minimal and its flow direction is opposite to that of the main airflow, leakage at the gap is further reduced under the influence of the main airflow.

[0099] Thus, the present invention effectively prevents airflow from flowing back through the gap between the impeller assembly 20 and the air guide 40, ensuring that the main airflow enters the impeller stably and evenly, reducing the degree of airflow turbulence within the fan and maintaining stable rotation of the impeller. Simultaneously, the blocking section 41 can block the airflow between the blades at the second end, allowing more gas to remain between the blades to fully perform work before entering the annular cavity section 331.

[0100] It should be noted that during airflow guidance, the centrifugal fan in this embodiment effectively suppresses airflow separation through its blade structure, significantly reducing the generation of vortices. Furthermore, by optimizing the structure and installation of the air guide 40 and blade assembly, the flow interference of backflow within the air cavity 33 on the main airflow is reduced. This significantly improves the fan's aerodynamic efficiency, reduces energy loss, enhances fan operational stability, and reduces vibration and noise.

[0101] As an optional embodiment, the volute 30 includes a first side panel 34, a second side panel 35, and a surrounding panel 36. Specifically, the first side panel 34 and the second side panel 35 are arranged opposite each other, and the surrounding panel 36 is arranged between the first side panel 34 and the second side panel 35. The first side panel 34, the second side panel 35, and the surrounding panel 36 together enclose an air cavity 33. The mounting opening 31 is provided on the first side panel 34, and the air outlet 32 ​​is provided on the surrounding panel 36. The second side panel 35 has a through opening. The centrifugal fan also includes a drive assembly, which includes a drive shaft 51. The drive shaft 51 passes through the through opening and is connected to the mounting disk 21. The drive assembly is used to drive the mounting disk 21 to rotate.

[0102] On the basis of this structure, during assembly, the drive shaft 51 is provided with a connecting end 511, the mounting plate 21 is provided with a hub 23, and the connecting end 511 is fixedly connected to the hub 23. Figure 10 The hub 23 includes a mounting groove, an axial end portion of the mounting groove is provided with a mounting hole, and a radial side of the mounting groove is provided with a protrusion; a groove is provided on the outer periphery of the connecting end 511, the connecting end 511 is inserted into the mounting groove, and the protrusion in the mounting groove is connected to the groove on the connecting end 511, limiting the circumferential separation of the drive shaft 51 and the mounting disk 21; the axial end surface of the connecting end 511 is also provided with a mounting hole, and the mounting hole is connected to the mounting hole of the mounting groove by a connecting member such as a bolt or a screw, thereby limiting the axial separation of the drive shaft 51 and the mounting disk 21.

[0103] When the centrifugal fan is started, the drive shaft 51 in the drive assembly begins to rotate, driven by a power source such as a motor. The drive shaft 51 passes through the opening in the second side panel 35 and connects to the mounting plate 21, thereby transmitting rotational power to the mounting plate 21 and driving the impeller assembly 20 to rotate at high speed. Ambient airflow enters through the mounting opening 31 in the first side panel 34, passes through the air guide channel 42 of the air guide 40, and after initial flow, enters the air cavity 33 enclosed by the first side panel 34, the second side panel 35, and the surrounding panel 36.

[0104] In the wind cavity 33, the airflow meets the high-speed rotating impeller assembly 20, and the blades exert centrifugal force on the airflow, causing the airflow to move from the center of the impeller to the edge, thereby gaining kinetic energy. The accelerated airflow enters the annular cavity section 331 between the volute 30 and the impeller assembly 20 along the edge of the impeller. The annular cavity section 331 is composed of the enclosure 36 and the outer edge of the impeller. Due to the restriction of the enclosure 36, the airflow flow space gradually expands. According to Bernoulli's principle, the airflow velocity decreases and the pressure increases, realizing the gas pressurization process. Finally, the pressurized airflow is discharged from the air outlet 32 ​​on the enclosure 36 and transported to the target position, completing the entire gas delivery process. During the operation of the fan, the various components of the volute 30 work closely together to provide a stable operating environment for the impeller assembly 20, while effectively guiding and constraining the airflow.

[0105] The drive assembly further includes a drive motor 50 , and the drive motor 50 and the drive shaft 51 are driven by direct connection, belt drive or coupling.

[0106] Also, see Figure 12 The air guide member 40 further includes an air guide ring 43, a mounting section 44, and an arcuate transition section 45. The mounting section 44 is disposed opposite the blocking section 41 and is connected to the axial ends of the air guide ring 43. The mounting section 44 is also connected to the air guide ring 43 via the arcuate transition section 45. Both the mounting section 44 and the blocking section 41 are flanges extending radially from the ends of the air guide ring 43. The flange of the mounting section 44 is mounted to the mounting opening 31 of the first side plate 34 using fasteners such as screws and bolts. The inner circumference of the air guide ring 43 and the arcuate transition section 45 forms the air guide channel 42.

[0107] Therefore, the mounting section 44 is connected by tight bolts to firmly fix the air guide 40 on the first side panel 34 to prevent the air guide 40 from loosening or displacement; the arc-shaped transition section 45 gradually guides the airflow to the direction of the impeller assembly 20 through smooth arc changes, thereby reducing the impact of the airflow and the channel wall and reducing energy loss.

[0108] The technical means disclosed in the solutions of the present invention are not limited to those disclosed in the above-mentioned embodiments, but also include technical solutions composed of any combination of the above-mentioned technical features. It should be noted that those skilled in the art may make various improvements and modifications without departing from the principles of the present invention, and such improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. A blade, characterized in that: The blade body comprises a first end and a second end at two ends in a first direction, the first end having a first end surface, the second end having a second end surface, and a plane parallel to the first end surface and the second end surface is defined as a cutting plane; The blade body includes a first wind guide surface and a second wind guide surface that are arranged back to back with each other. The intercepting plane intercepts the first wind guide surface to obtain a first wind guide line, and the first wind guide line includes a first arc segment and a straight line segment that are connected to each other; the intercepting plane intercepts the second wind guide surface to obtain a second wind guide line, and the second wind guide line includes at least two arc segments, and the curvature radii of the at least two arc segments are different.

2. The blade according to claim 1, characterized in that: The connecting point of the first arc segment and the straight line segment is defined as point A, and the tangent line L1 of the first arc segment at point A coincides with the straight line where the straight line segment is located.

3. The blade according to claim 1, characterized in that: The blade body includes a first section and a second section that are connected to each other, a plane section is provided on one side of the first section, and a first arc section is provided on one side of the second section; the first arc section is connected with the plane section to form the first wind-guiding surface; the intercepting plane intercepts the plane section to obtain the straight line segment, and the intercepting plane intercepts the first arc section to obtain the first arc segment.

4. The blade according to claim 3, characterized in that: Along the first direction, the curvature radii of the first arc segments obtained by intercepting the first arc segment by each of the intercepting planes are all the same.

5. The blade according to claim 3, characterized in that: The straight line direction in which the straight line segment is located is defined as a second direction. Along the first direction, the width of the first segment in the second direction gradually decreases.

6. The blade according to claim 1, characterized in that: The second wind-guiding surface includes three arc surface segments, which are the second arc surface segment, the third arc surface segment and the fourth arc surface segment connected in sequence. The intercepting plane intercepts the second arc surface segment to obtain the second arc line segment, the intercepting plane intercepts the third arc surface segment to obtain the third arc line segment, and the intercepting plane intercepts the fourth arc surface segment to obtain the fourth arc line segment; the curvature radius of the second arc line segment is smaller than the curvature radius of the third arc line segment, and the curvature radius of the third arc line segment is larger than the curvature radius of the fourth arc line segment.

7. The blade according to claim 6, characterized in that: Along the first direction, the curvature radii of the second arc segments obtained by the intercepting plane intercepting the second arc surface segment are all the same; the curvature radii of the third arc segments obtained by the intercepting plane intercepting the third arc surface segment are all the same; the curvature radii of the fourth arc segments obtained by the intercepting plane intercepting the fourth arc surface segment are all the same.

8. The blade according to claim 1, characterized in that: The inlet angle of the blade body is α, and the value range of α is 25°<α<49°; the outlet angle of the blade body is β, and the value range of β is 90°<β<140°.

9. The blade according to claim 8, characterized in that: Along the first direction, the inlet angle α on each intercepting plane gradually decreases, and the outlet angle β gradually increases.

10. An impeller assembly, characterized in that: It comprises a mounting plate and a plurality of blades as described in any one of claims 1 to 9, wherein the mounting plate has a central axis and a mounting surface, and the plurality of blade bodies are arranged at equal intervals along the circumferential direction around the central axis and are mounted on the mounting surface through the first end.

11. A centrifugal fan, characterized in that: The invention comprises a volute and an impeller assembly according to claim 10, wherein the impeller assembly is mounted on the volute.

12. The centrifugal fan according to claim 11, characterized in that: The centrifugal fan also includes an air guide member, the volute has a mounting port, an air outlet and an air cavity, the air guide member is installed at the mounting port, the impeller assembly is installed at the air cavity, and the air guide member and the impeller assembly are coaxially arranged; the air guide member is provided with an air guide channel, the air guide channel is communicated with the air cavity and guides the air flow into the air cavity, the air outlet is communicated with the air cavity and guides the air flow out of the air cavity; the air guide member is provided with a blocking section on the side facing the impeller assembly, the blocking section is spaced apart from the second end of the blade body, and forms an anti-leakage channel.

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