Fan blade, fan, and air-blowing device

Abstract

Disclosed in the present application are a fan blade, a fan, and an air-blowing device. The fan blade comprises a hub and a blade assembly, wherein the blade assembly comprises N blades, N being an integer greater than or equal to 2; the blades are connected to the hub, each blade comprising a first blade section and a second blade section, and a hollow region being provided between the first blade section and the second blade section; a pressure surface of the first blade section is connected to a suction surface of the second blade section, and a suction surface of the first blade section is connected to a pressure surface of the second blade section, and on a projection plane perpendicular to the axis of the hub; and projection points formed by the orthographic projections of curved surfaces of the blades do not overlap.

Description

Fans, fans and blowing equipment

[0001] This application claims priority to Chinese patent application No. 202311869658.1 filed on December 29, 2023, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the technical field of blowing equipment, and in particular to a fan blade, a fan and a blowing equipment. Background Art

[0003] Blowers are widely used in daily life. Axial-flow fans, such as floor fans, are popular among users due to their high wind power and wide airflow range. Traditional fans typically feature simple straight or curved blades. When the fan is turned up high, it often produces high noise levels, causing some discomfort to users. To achieve fan noise reduction, the blades require more complex shapes, which in turn makes it difficult to open the mold during injection molding, increasing the manufacturing complexity of the fan blades. Technical issues

[0004] The main purpose of this application is to propose a fan blade that aims to effectively reduce the noise during the operation of the fan blade, while reducing the difficulty of mold opening during injection molding of the fan blade, thereby facilitating production and manufacturing. Technical Solutions

[0005] To achieve the above objectives, the fan blade proposed in this application includes:

[0006] wheel hubs; and

[0007] a blade assembly comprising N blades, where N is an integer greater than or equal to 2; the blades are connected to the hub, the blades comprising a first segment and a second segment, and a hollow area is defined between the first segment and the second segment;

[0008] The pressure surface of the first segment is connected to the suction surface of the second segment, and the suction surface of the first segment is connected to the pressure surface of the second segment. On the projection surface perpendicular to the hub axis, the projection points formed by the orthographic projection of the blade curved surface have no overlap.

[0009] In one embodiment, on a projection plane perpendicular to the hub axis, there is no overlap between projection planes formed by orthographic projections of the N blades of the blade assembly.

[0010] In one embodiment, the blade further includes a bridging segment, which connects the first segment and an end of the second segment away from the hub, and the hollow area is enclosed by the first segment, the bridging segment and the second segment.

[0011] In one embodiment, the bridge segment comprises a flat surface opposite to the hub, the flat surface being parallel to the axis of the hub.

[0012] In one embodiment, the height of the blade in the radial direction of the fan blade is H1, and the width of the bridging segment in the axial direction of the fan blade is no more than 5%*H1.

[0013] In one embodiment, the bridging segment is provided at an end of the blade away from the hub.

[0014] In one embodiment, at the bridge segment portion, the leading edge line of the first segment is connected to the leading edge line of the second segment, and the trailing edge line of the first segment is connected to the trailing edge line of the second segment.

[0015] In one embodiment, the inner end of the first segment and the inner end of the second segment are respectively connected to the hub, the inner end of the first segment and the inner end of the second segment are spaced apart in the circumferential direction of the blade, and the first segment, the bridging segment, the second segment and the hub jointly define the hollow area.

[0016] In one embodiment, the first segment, the second segment and the bridge segment are integrally injection-molded; and / or,

[0017] The blades and the hub are integrally injection-molded.

[0018] In one embodiment, on a projection plane parallel to the hub axis, an orthographic projection formed by an end of the blade away from the hub comprises a hollow ring.

[0019] In one embodiment, on a projection surface perpendicular to the hub axis, the hollow area is projected to form a first projection, the hub axis is projected to form an axis P, a reference circle is constructed around the axis P on the axial projection surface of the blade, and the reference circle is defined to intercept the first projection to obtain a first distance L1, and the first distance L1 is greater than 1 mm.

[0020] In one embodiment, the first distance L1 is greater than 5 mm.

[0021] In one embodiment, on a projection plane perpendicular to the hub axis, the orthographic projection of the blade forms a second projection, the orthographic projection of the hub axis forms an axis P, a reference circle is constructed around the axis P on the axial projection plane of the blade, and the reference circle is defined to intercept the outer edge of the second projection to obtain a second distance L2. At the end of the blade away from the hub, the second distance L2 gradually decreases in the radial direction of the blade toward the side away from the hub.

[0022] In one embodiment, a reference cylindrical surface is constructed around the axis of the hub, and a cross section of the blade obtained by intercepting the reference cylindrical surface is defined as a blade profile;

[0023] The thickness of the airfoil leading edge of the first segment is greater than the thickness of the airfoil trailing edge of the first segment; and / or the thickness of the airfoil leading edge of the second segment is greater than the thickness of the airfoil trailing edge of the second segment.

[0024] The present application also proposes a fan, comprising the fan blades as described above, and a driving member connected to the fan blades, wherein the driving member is used to drive the fan blades to rotate.

[0025] The present application also proposes a blowing device, comprising the fan blades or blower as described above. Beneficial effects

[0026] The technical solution of the present application is to have a hollow area between the first and second segments of the blade. The hollow area has a certain guiding effect on the airflow on the blade. When the fan blade rotates, the airflow at the trailing edge of the blade is guided along the suction surface of the blade to the pressure surface of the blade through the hollow area. In this way, the airflow vortex at the trailing edge of the fan blade can be dispersed to prevent the airflow vortex from directly detaching from the trailing edge of the blade and generating a large shedding vortex noise. In addition, on the projection plane perpendicular to the axis of the hub, the projection points formed by the positive projection of the entire blade curved surface have no overlap, which greatly reduces the difficulty of mold opening of the annular blade and can be more conducive to production and manufacturing by injection molding. The technical solution of the present application can effectively reduce the noise during the operation of the fan blade, and at the same time can reduce the difficulty of mold opening during injection molding of the fan blade, which is convenient for production and manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0028] FIG1 is a schematic structural diagram of a fan blade according to an embodiment of the present application;

[0029] FIG2 is a front view of the fan blade in FIG1 ;

[0030] FIG3 is a projection view of the fan blade in FIG1 perpendicular to the hub axis;

[0031] FIG4 is a schematic diagram of a blade of a fan blade intersecting with a reference cylindrical surface to form a set of blade profiles;

[0032] FIG5 is a schematic diagram showing a fan blade intersecting with multiple reference cylindrical surfaces to form multiple groups of blade profiles;

[0033] FIG6 is a schematic diagram of the structure of the same set of blades in FIG5 after being unfolded into a planar state;

[0034] FIG7 is a schematic structural diagram of a bridging segment of the blade in FIG5 ;

[0035] FIG8 is a schematic structural diagram of the bridge segment in FIG7 from another perspective;

[0036] FIG9 is a schematic diagram of the structure of the bridge segment of the blade in a pair of proportions;

[0037] FIG10 is a schematic diagram of the orthographic projection of a fan blade according to another embodiment of the present application on a projection plane parallel to the hub axis.

[0038] Description of Figure Numbers:

[0039] Reference number name Reference number name 100 blade 22 second segment 10 hub 221a second leading edge point 20 blade 222b second trailing edge point 201 hollow area 221 second leading edge line 21 first segment 222 second trailing edge line 211a first leading edge point 223 second pressure side 212b first trailing edge point 224 second suction side 211 first leading edge line 23 bridging segment 212 first trailing edge line 231 hollow ring 213 first pressure side 232 plane 214 first suction side 300 reference cylindrical surface 201a first projection 20a second projection 23′ bridging segment 400 reference circle 211′ first leading edge line 221′ second leading edge line 212′ first trailing edge line 222′ second trailing edge line 213′ first pressure side 223′ second pressure side 214′ first suction side 224′ second suction side

[0040] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. Modes for Carrying Out the Invention

[0041] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0043] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0044] The present application proposes a fan blade 100 .

[0045] Referring to FIG. 1 to FIG. 5 , in one embodiment of the present application, the fan blade 100 includes:

[0046] Wheel hub 10;

[0047] The blade assembly includes N blades 20, where N is an integer greater than or equal to 2; the blade 20 is connected to the hub 10, and the blade 20 includes a first segment 21 and a second segment 22, with a hollow area 201 between the first segment 21 and the second segment 22; the pressure surface of the first segment 21 is connected to the suction surface of the second segment 22, and the suction surface of the first segment 21 is connected to the pressure surface of the second segment 22. On the projection plane perpendicular to the axis of the hub 10, the projection points formed by the orthographic projection of the curved surface of the entire blade 20 do not overlap.

[0048] The fan blade 100 includes a hub 10 and N blades 20 disposed on the periphery of the hub 10. The number of blades 20 can be set according to actual needs and is generally set to at least two, for example, two, three, five, or more. In one embodiment, 2≤N≤9, which can both ensure the work of the fan blade 100 and reduce the noise generated during the operation of the fan blade 100. In one embodiment, 4≤N≤7. The inner end (root) of the blade 20 is connected to the hub 10. There are various ways to connect the blade 20. For example, the blade 20 and the hub 10 can be integrally formed, or they can be assembled together using assembly structures such as screws and snaps, which are not specifically limited here. In some embodiments, the blade 20 may also include a bridging segment 23 connected between the first segment 21 and the second segment 22. There are various ways to form a single blade 20. For example, the first segment 21, the second segment 22, and the bridging segment 23 can be integrally formed, or they can be formed separately and then spliced ​​together, which are not specifically limited here. In one embodiment, the first segment 21, the second segment 22, and the bridge segment 23 are integrally injection molded, which increases the overall structural strength and stability of the blade 20 and simplifies the manufacturing process of the blade 20. In one embodiment, the blade 20 and the hub 10 are integrally injection molded, which increases the stability and reliability of the connection between the blade 20 and the hub 10 and simplifies the manufacturing process of the fan blade 100.

[0049] In one embodiment, at least portions of the first segment 21 and the second segment 22 are spaced apart in the circumferential and / or axial directions of the hub 10. It is understood that the spaced apart arrangement of at least portions of the first segment 21 and the second segment 22 in the circumferential and / or axial directions of the hub 10 may mean that at least portions of the first segment 21 and the second segment 22 are spaced apart only in the axial direction of the hub 10, in which case the first segment 21 and the second segment 22 are axially opposed to each other in the hub 10 and have a certain thickness corresponding to the hollow area 201; or at least portions of the first segment 21 and the second segment 22 are spaced apart only in the circumferential direction of the hub 10, in which case the first segment 21 and the second segment 22 are circumferentially opposed to each other in the hub 10 and have a certain width corresponding to the hollow area 201; or at least portions of the first segment 21 and the second segment 22 are spaced apart in both the axial and circumferential directions of the hub 10, in which case the first segment 21 and the second segment 22 are staggered on the hub 10.

[0050] It should be noted that the inner end of the blade 20 refers to the end thereof close to the hub 10, and the outer end refers to the end thereof away from the hub 10, that is, the inner end of the blade 20 corresponds to the root portion thereof, and the outer end of the blade 20 corresponds to the tip portion thereof. The leading edge of the blade 20 refers to the portion where the blade 20 first contacts the airflow during the rotation of the fan blade 100, and the trailing edge of the blade 20 refers to the portion where the airflow finally flows out of the blade 20, that is, in the air inlet direction of the fan blade 100, the airflow flows in from the leading edge of the blade 20 and flows out from the trailing edge of the blade 20. The pressure surface of the blade 20 is the side where the blade 20 moves relative to the airflow, that is, the direction of the airflow facing the blade 20. Correspondingly, the suction surface of the blade 20 refers to the other side where the blade 20 moves relative to the airflow, that is, the direction of the blade 20 facing away from the airflow.

[0051] It is understandable that the noise of traditional axial flow fans comes in part from the shedding vortex formed at the trailing edge of the blade as the fan rotates. That is, when the fan blade rotates, the airflow forms a vortex at the trailing edge of the blade, and the vortex directly sheds from the trailing edge of the blade, generating a lot of noise. In the technical solution of the present application, the first segment 21, the bridging segment 23 and the second segment 22 of the blade 20 jointly enclose a hollow area 201, and the hollow area 201 has a certain guiding effect on the airflow on the blade 20. When the fan blade 100 rotates, the airflow at the trailing edge of the blade 20 is guided along the suction surface of the blade 20 to the pressure surface of the blade 20 through the hollow area 201. In this way, the airflow vortex at the trailing edge of the fan blade 100 can be dispersed to avoid the airflow vortex directly detaching from the trailing edge of the blade 20 to generate a large shedding vortex noise; on the other hand, by connecting the outer end of the first segment 21 with the outer end of the second segment 22 through the bridging segment 23, the leakage vortex at the outer end of the blade 20 can be further reduced, the noise of the fan blade 100 is further reduced, and on the other hand, the working capacity of the fan blade 100 can also be improved.

[0052] It should be noted that on the projection plane perpendicular to the axis of the hub 10, the projection points formed by the orthographic projection of the entire blade 20 curved surface do not overlap. It should be understood that the projection points of the entire blade curved surface do not overlap substantially without affecting the smooth opening of the mold. In actual applications, due to certain manufacturing errors in the production process of the fan blade 100, there may be some overlap in the projection points of the entire blade 20 curved surface. For example, as long as the area occupied by all overlapping points on the blade curved surface does not exceed 5% of the projected area of ​​the entire blade 20 curved surface, it can be considered that there is substantially no overlap.

[0053] The technical solution of the present application forms a hollow region 201 between the first segment 21 and the second segment 22 of the blade 20. This hollow region 201 has a certain guiding effect on the airflow on the blade 20. When the fan blade 100 rotates, the airflow at the trailing edge of the blade 20 is guided along the suction surface of the blade 20 to the pressure surface of the blade 20 through the hollow region 201. In this way, the airflow vortex at the trailing edge of the blade 100 can be dispersed, preventing the airflow vortex from directly detaching from the trailing edge of the blade 20 and generating a large shedding vortex noise. On the other hand, the outer end of the first segment 21 is connected to the outer end of the second segment 22 by the bridge segment 23, which can further reduce the leakage vortex at the outer end of the blade 20, further reducing the noise of the fan blade 100, and also improving the work performance of the fan blade 100. In addition, on the projection plane perpendicular to the axis of the hub 10, the projection points formed by the orthographic projection of the entire blade 20 curved surface do not overlap, which greatly reduces the difficulty of mold opening of the annular blade 20 and is more conducive to production by injection molding. The technical solution of the present application can effectively reduce the noise of the fan blade 100 during operation, and at the same time can reduce the difficulty of opening the mold during injection molding of the fan blade 100, thereby facilitating production and manufacturing.

[0054] In one embodiment, on a projection plane perpendicular to the axis of the hub 10, there is no overlap between the projection planes formed by the orthographic projections of the N blades 20 of the blade assembly. This ensures smooth mold opening of the entire fan blade 100 and each blade 20.

[0055] In one embodiment, the blade 20 further includes a bridging segment 23 , which connects the first segment 21 and the second segment 22 at one end away from the hub 10 , and the hollow area 201 is enclosed between the first segment 21 , the bridging segment 23 and the second segment 22 .

[0056] The first segment 21, the bridge segment 23, and the second segment 22 collectively enclose a hollow area 201, which means that the first segment 21, the bridge segment 23, and the second segment 22 collectively enclose a ring structure, and the hollow area 201 is the center of the ring structure. The ring structure can be either a closed ring or a non-closed ring. For example, the first segment 21, the bridge segment 23, and the second segment 22 are connected end to end, and the three together enclose a closed ring structure. For another example, the first segment 21, the bridge segment 23, and the second segment 22 are connected in sequence, and a gap is formed between the inner end of the first segment 21 and the inner end of the second segment 22, and they are respectively connected to the hub 10. In this case, the first segment 21, the bridge segment 23, and the second segment 22 collectively enclose a non-closed ring structure, but the first segment 21, the bridge segment 23, the second segment 22, and the hub 10 collectively enclose a closed ring structure.

[0057] To further reduce the difficulty of mold opening, in one embodiment, the bridging segment 23 includes a flat surface 232 opposite to the hub 10, and the flat surface 232 is parallel to the axis of the hub 10. It should be noted that the flat surface 232 of the bridging segment 23 is parallel to the axis of the hub 10. It should be understood that, without affecting mold opening, the flat surface 232 of the bridging segment 23 is substantially parallel to the axis of the hub 10. In other words, a certain angle is allowed between the flat surface 232 of the bridging segment 23 and the axis of the hub 10 (for example, the angle can be 1° to 5°, or other values ​​as long as it does not affect mold opening). Of course, the flat surface 232 of the bridging segment 23 can also be parallel to the axis of the hub 10.

[0058] As shown in Figures 3 and 5, in one embodiment, the height of the blade 20 in the radial direction of the fan blade 100 is H1, and the width of the bridging segment 23 in the axial direction of the fan blade 100 is L0, where L0 is not greater than 5%*H1. In other words, L0 ≤ 5%*H1. In this way, the width of the bridging segment 23 is controlled within an appropriate range, which can effectively reduce the noise during the operation of the fan blade 100. Specifically, the outer contour of the fan blade 100 has a first diameter D1, and the hub 10 has a second diameter D2; wherein H1 = (D1-D2).

[0059] Furthermore, the bridging segment 23 is provided at one end of the blade 20 away from the hub 10. That is, the bridging segment 23 can be provided as far away from the hub 10 as possible, thus reducing interference with the mainstream of the airflow sucked by the blade 20.

[0060] Since the present technical solution optimizes the design of the structure of the fan blade 100, it can reduce the difficulty of opening the mold during injection molding, making it more suitable for the injection molding process. In one embodiment, the first segment 21, the second segment 22 and the bridging segment 23 are integrally injection molded, so that the overall structural strength of the blade 20 is higher and the stability is better, and the manufacturing process of the blade 20 can also be simplified. In one embodiment, the blade 20 and the hub 10 are integrally injection molded, so that the connection between the blade 20 and the hub 10 is more stable and reliable, and the manufacturing process of the fan blade 100 can also be simplified. It is worth noting that although the structure of the fan blade 100 in the present technical solution is more suitable for an integral injection molding process, in actual applications, other molding methods (such as 3D printing) can also be used for production and manufacturing, all of which are within the scope of protection of this application.

[0061] The blade 20 has a first leading edge line 211 and a first trailing edge line 212 disposed on both sides of the first segment 21 , and a second leading edge line 221 and a second trailing edge line 222 disposed on both sides of the second segment 22 .

[0062] As shown in Figure 4 , a reference cylindrical surface 300 is constructed around the axis of the hub 10, and the cross-section of the blade 20 obtained by the reference cylindrical surface 300 is defined as a blade profile. The blade profiles of the first segment 21 and the second segment 22 cut from the reference cylindrical surface 300 of the same radius are defined as belonging to the same group. Figure 5 shows four groups of blade profiles cut from reference cylindrical surfaces 300 of four different radii, including blade profiles 21a and 22a, blade profiles 21b and 22b, blade profiles 21c and 22c, and blade profiles 21d and 22d. Blade profiles 21a and 22a, belonging to the same group, are located at the root of blade 20, while the other three groups of blade profiles are spaced apart in a direction approaching the blade tip.

[0063] Referring to Figures 5 and 6 , unfold one set of blade profiles (e.g., blade profile 21c and blade profile 22c) along the circumferential direction into a planar configuration. In the rotational direction of blade 100, the blade profile of first segment 21 (e.g., blade profile 21c) is located upstream of the blade profile of second segment 22 (e.g., blade profile 22c). The blade profile of first segment 21 (e.g., blade profile 21c) has a first leading edge point 211a and a first trailing edge point 212b. In the rotational direction of blade 100, first leading edge point 211a is located upstream of first trailing edge point 212b. The first leading edge points 211a of the multiple blade profiles (e.g., 21a, 21b, 21c, 21d, etc.) of the first segment 21 are sequentially connected to form a first leading edge line 211. The first trailing edge points 212b of the multiple blade profiles (e.g., 21a, 21b, 21c, 21d, etc.) of the first segment 21 are sequentially connected to form a first trailing edge line 212. The first leading edge line 211 and the first trailing edge line 212 extend to the bridge segment 23. The blade profiles of the second segment 22 (e.g., blade profile 22c) have a second leading edge point 221a and a second trailing edge point 222b. In the rotation direction of the fan blade 100, the second leading edge point 221a is located upstream of the second trailing edge point 222b. The second leading edge points 221a of multiple blade profiles (such as 22a, 22b, 22c, 22d, etc.) of the second segment 22 are connected in sequence to form a second leading edge line 221, and the second trailing edge points 222b of multiple blade profiles (such as 22a, 22b, 22c, 22d, etc.) of the second segment 22 are connected in sequence to form a second trailing edge line 222; the second leading edge line 221 and the second trailing edge line 222 extend to the bridging segment 23.

[0064] As shown in Figure 6, the blade profile of the first segment 21 (such as blade profile 21c) is separated at the first leading edge point 211a and the first trailing edge point 212b to obtain two side profile lines. The side of the blade profile of the first segment 21 that is closer to the rotation direction of the fan blade 100 is defined as the first pressure side 213, and the other side is defined as the first suction side 214. The blade profile of the second segment 22 (such as blade profile 22c) is separated at the second leading edge point 221a and the second trailing edge point 222b to obtain two side profile lines. The side of the blade profile of the second segment 22 that is closer to the rotation direction of the fan blade 100 is defined as the second pressure side 223, and the other side is defined as the second suction side 224. The first pressure side 213 profile lines of the multiple blade profiles of the first segment 21 are stacked to form the pressure surface of the first segment 21, and the first suction side 214 profile lines of the multiple blade profiles are stacked to form the suction surface of the first segment 21. The second pressure side 223 profiles of the plurality of airfoil profiles of the second segment 22 are stacked to form the pressure surface of the second segment 22, while the second suction side 224 profiles of the plurality of airfoil profiles are stacked to form the suction surface of the second segment 22. It will be appreciated that the pressure surface of the blade 20 is the side of the blade 20 facing the airflow, while the suction surface of the blade 20 is the side of the blade 20 facing away from the airflow.

[0065] As shown in FIG7 , in one embodiment, at the bridging segment 23 , the leading edge line of the first segment 21 (i.e., the first leading edge line 211 ) is connected to the leading edge line of the second segment 22 (i.e., the second leading edge line 221 ), and the trailing edge line of the first segment 21 (i.e., the first trailing edge line 212 ) is connected to the trailing edge line of the second segment 22 (i.e., the second trailing edge line 222 ).

[0066] In this embodiment, by optimizing the configuration of the bridge segment 23, the configuration of the entire blade 20 is made smoother, which can play a better role in guiding airflow. For example, in the rotation direction of the fan blade 100, the first segment 21 is located upstream of the second segment 22, and the outer end of the first segment 21 and the outer end of the second segment 22 are connected together by the bridge segment 23. The pressure surface of the first segment 21 is connected to the suction surface of the second segment 22 via the outer side surface of the bridge segment 23, and the suction surface of the first segment 21 is connected to the pressure surface of the second segment 22 via the inner side surface of the bridge segment 23. When the fan blade 100 rotates, the airflow vortex at the outer end of the pressure surface of the first segment 21 can flow along the outer side surface of the bridge segment 23 to the suction surface of the second segment 22, which can effectively reduce the shedding vortex noise at the outer end of the first segment 21 and effectively reduce the noise of the fan blade 100 during operation. The airflow vortex at the outer end of the pressure surface of the second segment 22 can be guided to the suction surface of the first segment 21 along the inner side surface of the bridging segment 23, which can effectively reduce the shedding vortex noise at the outer end of the first segment 21 and the noise of the fan blade 100 during operation.

[0067] Figure 9 is a schematic structural diagram of the bridging segment 23' in a comparative example. The connection structure of the bridging segment in the comparative example is different from that of the bridging segment in this embodiment. That is, in the comparative example, at the bridging segment 23', the leading edge line of the first segment (that is, the first leading edge line 211') is connected to the trailing edge line of the second segment (that is, the second trailing edge line 222'), the trailing edge line of the first segment (that is, the first trailing edge line 212') is connected to the leading edge line of the second segment (that is, the second leading edge line 221'), the suction side of the first segment (that is, the first suction side 214') is connected to the suction side of the second segment (that is, the second suction side 224'), and the pressure side of the first segment (that is, the first pressure side 213') is connected to the pressure side of the second segment (that is, the second pressure side 214').

[0068] Performance tests were conducted on a fan with the bridge-segment structure of this embodiment (hereinafter referred to as the present embodiment) and a fan with the bridge structure of the comparative example (hereinafter referred to as the comparative example). Under the same blade size and airflow rate, the present embodiment produced at least 3dB less noise than the comparative example. This indicates that the bridge-segment structure of this embodiment effectively reduces fan noise while maintaining the same airflow rate.

[0069] At the bridging segment 23, the first leading edge line 211 smoothly transitions with the second leading edge line 221, the first trailing edge line 212 smoothly transitions with the second trailing edge line 222, the pressure side of the first segment 21 smoothly transitions with the suction side of the second segment 22, and the suction side of the first segment 21 smoothly transitions with the pressure side of the second segment 22. This optimizes the flow field of the blade 20 in the hollow region 201, particularly at the tip, and helps maintain the shape of the hollow region 201. It also makes the connections between the segments smoother, avoiding undercuts, thereby further reducing the difficulty of opening the mold during injection molding of the blade 20 and further reducing the manufacturing difficulty of the fan blade 100.

[0070] As shown in Figures 8 and 10, in some embodiments, the orthographic projection formed by the end of the blade 20 away from the hub 10 (e.g., the bridge segment 23) on a projection plane parallel to the axis of the hub 10 has a hollow ring 231. This allows the airflow velocity through the hollow ring 231 to be higher, reducing the rotational speed of the fan blade 100 while achieving the same air volume, thereby reducing the noise and power of the fan or hair dryer equipped with the fan blade 100.

[0071] As shown in Figure 2, in one embodiment, the hollow area 201 is projected on the projection surface perpendicular to the axis of the hub 10 to form a first projection 201a, and the axis of the hub 10 is projected to form an axis P. A reference circle 400 is constructed around the axis P on the axial projection surface of the fan blade 100. The reference circle 400 is defined to intercept the first projection 201a to obtain a first distance L1, and the first distance L1 is greater than 1mm. It can further ensure that the projection points formed by the curved surface of the blade 20 on the axial projection surface of the fan blade 100 do not overlap, so that the difficulty of opening the mold of the annular blade 20 is greatly reduced, which can be more conducive to production and manufacturing by injection molding. In one embodiment, the first distance L1 is greater than 5mm. For example, L1 can be 6mm, 7mm, 8mm, etc.

[0072] As shown in FIG2 , in one embodiment, the orthographic projection of blade 20 on a projection plane perpendicular to the axis of hub 10 forms a second projection 20a. The orthographic projection of the axis of hub 10 forms axis P. A reference circle 400 is constructed around axis P on the axial projection plane of blade 100. The outer edge of second projection 20a intercepted by reference circle 400 is defined as a second distance L2. At the end of blade 20 away from hub 10 (i.e., at bridging segment 23), second distance L2 gradually decreases in the radial direction of blade 100 toward the side away from hub 10. This makes the outer contour of the entire blade 20 more streamlined, reduces the resistance of airflow flowing along the outer contour of blade 20, and thus further reduces noise.

[0073] As shown in FIG6 , in some embodiments, a reference cylindrical surface 300 is constructed around the axis of the hub 10, and a cross-section of the blade 20 obtained by cutting the reference cylindrical surface 300 is defined as the airfoil; the leading edge thickness of the first segment 21 is greater than the trailing edge thickness of the first segment 21; and / or, the leading edge thickness of the second segment 22 is greater than the trailing edge thickness of the second segment 22. It should be noted that the thickness dimension of the airfoil refers to the width dimension of the airfoil in a direction perpendicular to the arc line thereof.

[0074] With this arrangement, the leading edge blade profile of the first segment 21 and / or the second segment 22 is thicker, while the trailing edge blade profile is relatively thinner. That is, the blade profile exhibits the characteristics of a thick leading edge and a thin trailing edge, which is beneficial for improving the flow field on the first segment 21 and the second segment 22, thereby reducing the aerodynamic noise of the fan blade 100. In addition, in actual applications, some fan blades 100 are installed in a mesh cover, and the interference between the mesh cover and the fan blade 100 is strong, which will generate relatively large noise. In this technical solution, the leading edge blade profile of the first segment 21 and / or the second segment 22 is thicker, which enhances the adaptability to the uneven flow at the outlet of the air inlet mesh cover; while the trailing edge blade profile of the first segment 21 and / or the second segment 22 is thinner, which can reduce the unevenness of the outlet velocity of the blade 20 and reduce the interference with the mesh cover. In this way, since the interference between the fan blade 100 and the air inlet and outlet mesh covers is reduced, the noise of the fan can be significantly reduced, and the efficiency of the entire machine can also be improved.

[0075] In one embodiment, the maximum blade thickness of the first segment 21 is located within a 30% chord length region from the first leading edge line 211, and the ratio of the maximum blade thickness to the blade chord length ranges from 5% to 35%. The maximum blade thickness of the second segment 22 is located within a 30% chord length region from the second leading edge line 221, and the ratio of the maximum blade thickness to the blade chord length ranges from 5% to 35%. In this way, the leading edges of the first segment 21 and the second segment 22 can effectively resist inlet distortion and produce a weaker wake low-speed zone, thereby further reducing the aerodynamic noise of the fan blade 100. Of course, in other embodiments, the leading edge blade thickness of the first segment 21 can be less than or equal to the trailing edge blade thickness of the first segment 21; and / or the leading edge blade thickness of the second segment 22 can be less than or equal to the trailing edge blade thickness of the second segment 22.

[0076] There are various specific configurations for the hollow region 201. As shown in FIG1 , in one embodiment, the inner ends of the first segment 21 and the second segment 22 are respectively connected to the hub 10 . The inner ends of the first segment 21 and the second segment 22 are spaced apart in the circumferential direction of the blade 100 . The first segment 21 , the bridging segment 23 , the second segment 22 , and the hub 10 collectively define the hollow region 201 . In other words, the first segment 21 , the bridging segment 23 , the second segment 22 , and the hub 10 collectively enclose an annular structure. This increases the effective length of the first segment 21 and the second segment 22 , thereby improving the overall performance of the blade 20 .

[0077] For example, in another embodiment, the inner end of the first segment 21 is connected to the side edge of the second segment 22, and the inner end of the second segment 22 is connected to the hub 10. That is, the inner end of the second segment 22 serves as the root of the blade 20 and is directly connected to the hub 10, while the first segment 21 is not directly connected to the hub 10. In other words, the end of the blade 20 away from the hub 10 is curved in a direction opposite to the direction of rotation of the fan blade 100 to form a hollow region 201. This can make the root of the blade 20 more compact, which helps reduce the weight of the blade 20. For another example, in one embodiment, the inner end of the first segment 21 and the inner end of the second segment 22 are connected and are also connected to the hub 10. That is, the root of the blade 20 is formed by both the first segment 21 and the second segment 22, and the hollow region 201 is directly formed on the blade 20. This can improve the structural strength of the root of the blade 20. In addition, in some embodiments, a filter net may be provided in the hollow area 201 to also play a role in filtering and purification.

[0078] The present application also proposes a fan, comprising a fan blade 100 and a driving member connected to the fan blade 100, the driving member being used to drive the fan blade 100 to rotate. The specific structure of the fan blade 100 refers to the above embodiment. Since the fan adopts all the technical solutions of all the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be described one by one here. Specifically, the fan can be an axial flow fan with axial flow fan blades 100, and the driving member can be any one of an electric motor, a hydraulic motor or a pneumatic motor.

[0079] The present application also proposes a blowing device, including a fan blade 100 or a blower. The specific structure of the fan blade 100 or the blower refers to the above-mentioned embodiment. Since the present blowing device adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought by the technical solutions of the above-mentioned embodiments, which will not be described one by one here. Among them, the blowing device includes but is not limited to fan products such as floor fans, ceiling fans, and desktop fans. The blowing device can also be other devices with axial flow fan blades 100 (such as air conditioner outdoor units). By adopting the above-mentioned fan blades 100 or blowers, the noise of the blowing device can be effectively reduced and the user experience can be improved.

[0080] The above description is merely an optional embodiment of the present application and does not limit the patent scope of the present application. All equivalent structural transformations made using the contents of the present application specification and drawings under the inventive concept of the present application, or direct / indirect application in other related technical fields are included in the patent protection scope of the present application.

Claims

1. A fan blade, wherein, The fan blade includes: a hub; and a blade assembly including N blades, where N is an integer greater than or equal to 2; the blades are connected to the hub, and each blade includes a first segment and a second segment, and there is a hollow area between the first segment and the second segment; The pressure surface of the first segment is connected to the suction surface of the second segment, and the suction surface of the first segment is connected to the pressure surface of the second segment. On the projection plane perpendicular to the axis of the hub, the projection points formed by the orthographic projection of the blade surface do not overlap.

2. The fan blade according to claim 1, wherein, On the projection plane perpendicular to the axis of the hub, the projection planes formed by the orthographic projections of the N blades of the blade assembly do not overlap.

3. The fan blade according to claim 1, wherein, The blade further includes a bridging segment that connects the ends of the first segment and the second segment away from the hub, and the hollow area is enclosed between the first segment, the bridging segment, and the second segment.

4. The fan blade according to claim 3, wherein, The bridging segment includes a plane opposite to the hub, and the plane is parallel to the axis of the hub.

5. The fan blade according to claim 3, wherein, The height of the blade in the radial direction of the fan blade is H1, and the width of the bridging segment in the axial direction of the fan blade is not greater than 5%*H1.

6. The fan blade according to claim 3, wherein, The bridging segment is provided at the end of the blade away from the hub.

7. The fan blade according to claim 3, wherein, At the position of the bridging segment, the leading edge line of the first segment is connected to the leading edge line of the second segment, and the trailing edge line of the first segment is connected to the trailing edge line of the second segment.

8. The fan blade according to claim 3, wherein, The inner ends of the first segment and the second segment are respectively connected to the hub, and there is a gap between the inner ends of the first segment and the second segment in the circumferential direction of the fan blade. The first segment, the bridging segment, the second segment, and the hub jointly define the hollow area.

9. The fan blade according to claim 3, wherein, The first segment, the second segment, and the bridging segment are integrally injection-molded; and / or, The blade and the hub are integrally injection-molded.

10. The fan blade according to claim 1, wherein, On the projection plane parallel to the axis of the hub, the orthographic projection formed at the end of the blade away from the hub has a hollow ring.

11. The fan blade according to claim 1, wherein, On the projection plane perpendicular to the axis of the hub, the orthographic projection of the hollow area forms a first projection, the orthographic projection of the hub axis forms an axis center P, a reference circle is configured on the axial projection plane of the fan blade around the axis center P, and a first distance L1 is defined as the first projection intercepted by the reference circle. The first distance L1 is greater than 1 mm.

12. The fan blade according to claim 11, wherein, The first distance L1 is greater than 5 mm.

13. The fan blade according to claim 1, wherein, On the projection plane perpendicular to the axis of the hub, the orthographic projection of the blade forms a second projection, the orthographic projection of the hub axis forms an axis center P, a reference circle is configured on the axial projection plane of the fan blade around the axis center P, and a second distance L2 is defined as the outer edge of the second projection intercepted by the reference circle. At the end of the blade away from the hub, the second distance L2 gradually decreases in the radial direction of the fan blade towards the side away from the hub.

14. The fan blade according to any one of claims 1 to 13, wherein, A reference cylindrical surface is configured around the axis of the hub, and the cross-section obtained by the reference cylindrical surface intercepting the blade is defined as the blade profile; The leading-edge thickness of the blade profile of the first segment is greater than the trailing-edge thickness of the blade profile of the first segment; And / or, the thickness of the leading edge of the airfoil of the second segment is greater than the thickness of the trailing edge of the airfoil of the second segment.

15. A fan, wherein, The fan includes the fan blade according to any one of claims 1 to 14, and a driving member connected to the fan blade, and the driving member is configured to drive the fan blade to rotate.

16. A blowing device, wherein, The blowing device includes the fan blade according to any one of claims 1 to 14 or the fan according to claim 15.

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