Fan blade, fan and blowing equipment

Abstract

The invention discloses a fan blade, a fan and blowing equipment, the fan blade comprises a hub and a blade assembly, the blade assembly comprises N blades, and N is an integer greater than or equal to 2; the blades are connected with the hub, each blade comprises a first segment and a second segment, and a hollow area is formed between each first segment and the corresponding second segment; the pressure surface of the first segment is connected with the suction surface of the second segment, the suction surface of the first segment is connected with the pressure surface of the second segment, and projection points formed by orthographic projection of the curved surface of the blade on a projection surface perpendicular to the axis of the hub are not overlapped. According to the technical scheme, the fan blade operation noise can be lowered, the mold opening difficulty during fan blade injection molding is lowered, and production and manufacturing are convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of blowing equipment, and in particular to a fan blade, a fan and blowing equipment. Background Art

[0002] Blowing equipment is widely used in people's daily lives. Among them, blowing equipment using axial flow fan blades (such as floor fans) are favored by many users because of their strong wind force and wide blowing range. The blades of traditional fans generally adopt a simple straight plate or curved plate structure. When the blowing equipment is turned on at a higher gear, the noise is often relatively loud, which will cause certain troubles to users. In order to achieve fan noise reduction, the blades need to be designed with a more complex shape, which will make it difficult to open the mold during injection molding of the fan blades, increasing the difficulty of manufacturing the fan blades. Summary of the Invention

[0003] The main purpose of the present invention is to propose a fan blade, which aims to effectively reduce the noise during the operation of the fan blade, and at the same time reduce the difficulty of opening the mold during the injection molding of the fan blade, thereby facilitating production and manufacturing.

[0004] To achieve the above-mentioned object, the fan blade proposed by the present invention includes:

[0005] wheel hub;

[0006] 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;

[0007] 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.

[0008] 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.

[0009] 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 between the first segment, the bridging segment and the second segment.

[0010] In one embodiment, the bridge segment includes a flat surface opposite to the hub, and the flat surface is parallel to the axis of the hub.

[0011] 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.

[0012] In one embodiment, the bridging segment is provided at an end of the blade away from the hub.

[0013] 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.

[0014] 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.

[0015] In one embodiment, the first segment, the second segment and the bridge segment are integrally injection-molded; and / or,

[0016] The blades and the hub are integrally injection-molded.

[0017] 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.

[0018] In one embodiment, on the 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 fan 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.

[0019] In one embodiment, the first distance L1 is greater than 5 mm.

[0020] 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.

[0021] 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;

[0022] 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.

[0023] The present invention further provides 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.

[0024] The present invention also provides a blowing device, comprising the fan blade or blower as described above.

[0025] The technical solution of the present invention has a hollow area between the first segment and the second segment 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 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 invention 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

[0026] In order to more clearly illustrate the embodiments of the present invention 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 invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying any creative work.

[0027] Figure 1 This is a schematic structural diagram of an embodiment of a fan blade of the present invention;

[0028] Figure 2 for Figure 1 Front view of the middle fan blade;

[0029] Figure 3 for Figure 1 Projection view of the middle fan blade perpendicular to the hub axis;

[0030] Figure 4 A schematic diagram of a blade of a fan blade intersecting with a reference cylindrical surface to form a set of blade profiles;

[0031] Figure 5A schematic diagram of a fan blade intersecting with multiple reference cylindrical surfaces to form multiple sets of blade profiles;

[0032] Figure 6 for Figure 5 Schematic diagram of the structure of the same set of blades after unfolding into a plane state;

[0033] Figure 7 for Figure 5 Schematic diagram of the structure of the bridging segment of the middle blade;

[0034] Figure 8 for Figure 7 A structural diagram of the middle bridge segment from another perspective;

[0035] Figure 9 Schematic diagram of the structure of the bridging segment of the blade in a pair of scales;

[0036] Figure 10 It is a schematic diagram of the orthographic projection of a fan blade on a projection plane parallel to the hub axis according to another embodiment of the present invention.

[0037] Description of Figure Numbers:

[0038] Label name Label name 100 fan blades 22 Second segment 10 wheel hub 221a Second leading edge point 20 blade 222b Second trailing edge point 201 Hollow area 221 Second leading edge line 21 First Clip 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 Bridge Clip 212 First trailing edge line 231 Hollow ring 213 First pressure side 232 flat 214 First suction side 300 Reference cylindrical surface 201a First Projection 20a Second projection 23’ Bridge Clip 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

[0039] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings and in conjunction with the embodiments. DETAILED DESCRIPTION

[0040] 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.

[0041] It should be noted that if the embodiments of the present invention involve directional indications (such as up, down, left, right, front, back, etc.), the 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 indications will also change accordingly.

[0042] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present invention, 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 solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or solutions that satisfy both A and B. 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. 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 the present invention.

[0043] The present invention provides a fan blade 100 .

[0044] Please refer to Figures 1 to 5 In one embodiment of the present invention, the fan blade 100 includes:

[0045] Wheel hub 10;

[0046] 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.

[0047] The fan blade 100 includes a hub 10 and N blades 20 arranged on the periphery of the hub 10, wherein the number of blades 20 can be set according to actual needs, and is generally set to at least two, for example, it can be two, three, five or more; preferably, 2≤N≤9, which can not only ensure the work done by the fan blade 100, but also reduce the noise generated during the operation of the fan blade 100. More preferably, 4≤N≤7. The inner end (root) of the blade 20 is connected to the hub 10, and there are many ways to connect it. For example, the blade 20 and the hub 10 can be integrally formed, or they can be assembled together by 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 many 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, which are not specifically limited here. Optionally, 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. Optionally, 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.

[0048] Optionally, 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.

[0049] 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.

[0050] 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 invention, 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 the working capacity of the fan blade 100 can be improved on the other hand.

[0051] It should be noted that on a projection plane perpendicular to the axis of the hub 10, the projection points formed by the orthographic projection of the entire curved surface of the blade 20 do not overlap. This means that the projection points of the entire curved surface of the blade do not overlap substantially without affecting smooth mold opening. In actual applications, due to certain manufacturing errors in the production process of the fan blade 100, some of the projection points of the entire curved surface of the blade 20 may overlap. 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 curved surface of the blade 20, it can be considered that there is substantially no overlap.

[0052] The technical solution of the present invention 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. This can disperse the airflow vortex at the trailing edge of the blade 100 and prevent 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 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 invention 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] To further reduce the difficulty of mold opening, in one embodiment, the bridging segment 23 includes a plane 232 opposite to the hub 10, and the plane 232 is parallel to the axis of the hub 10. It should be noted that the plane 232 of the bridging segment 23 is parallel to the axis of the hub 10. It should be understood that, without affecting the mold opening, the plane 232 of the bridging segment 23 is substantially parallel to the axis of the hub 10, that is, a certain angle is allowed between the plane 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 the mold opening). Of course, the plane 232 of the bridging segment 23 can also be parallel to the axis of the hub 10.

[0057] like Figure 3 and Figure 5 As shown, 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 bridge segment 23 in the axial direction of the fan blade 100 is L0, wherein L0 is not greater than 5%*H1. That is, L0≤5%*H1, so that the width of the bridge segment 23 is controlled within a suitable 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,

[0058] 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.

[0059] 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. Optionally, 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. Optionally, 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 the present invention.

[0060] 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 .

[0061] like Figure 4 As shown, a reference cylindrical surface 300 is constructed around the axis of the hub 10, and the cross section of the blade 20 intercepted by the reference cylindrical surface 300 is defined as the blade profile; the blade profiles of the first segment 21 and the second segment 22 intercepted by the reference cylindrical surface 300 with the same radius are defined to belong to the same group. Figure 5 A total of four groups of blade profiles cut out by four reference cylindrical surfaces 300 of different radii are shown, including blade profile 21a and blade profile 22a, blade profile 21b and blade profile 22b, blade profile 21c and blade profile 22c, and blade profile 21d and blade profile 22d. Among them, blade profile 21a and blade profile 22a belonging to the same group are located at the root of blade 20, and the other three groups of blade profiles are distributed in sequence along the direction close to the blade tip.

[0062] Please combine Figure 5 and Figure 6 , one set of blade profiles (e.g., blade profile 21c and blade profile 22c) is unfolded into a planar state along the circumferential direction. In the rotation direction of fan 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 rotation direction of fan 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, and 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 profile of the second segment 22 (e.g., blade profile 22c) has 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.

[0063] like Figure 6As shown, 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, defining the side of the blade profile of the first segment 21 close to the rotation direction of the fan blade 100 as the first pressure side 213, and the other side 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, defining the side of the blade profile of the second segment 22 close to the rotation direction of the fan blade 100 as the second pressure side 223, and the other side as the second suction side 224. Then, 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.

[0064] like Figure 7 As shown, 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).

[0065] 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.

[0066] Figure 93 is a structural schematic 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').

[0067] 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.

[0068] Optionally, 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 connection between the segments smoother, avoiding undercuts, thereby further reducing the difficulty of opening the mold for the blade 20 during injection molding, which helps further reduce the manufacturing difficulty of the fan blade 100.

[0069] like Figure 8 and Figure 10 As shown, in some embodiments, on a projection plane parallel to the axis of the hub 10, the orthographic projection formed by the end of the blade 20 away from the hub 10 (e.g., the bridge segment 23) has a hollow ring 231. This allows the airflow velocity through the hollow ring 231 to be higher, and while achieving the same air volume, the rotation speed of the fan blade 100 can be reduced, thereby reducing the noise and power of the fan or hair dryer equipped with the fan blade 100.

[0070] like Figure 2As shown, 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 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 1 mm. It can further ensure that the projection points formed by the curved surface of the blade 20 on the axial projection surface of the 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 by injection molding. Optionally, the first distance L1 is greater than 5 mm. For example, L1 can be 6 mm, 7 mm, 8 mm, etc.

[0071] like Figure 2 As shown, in one embodiment, the orthographic projection of the blade 20 on the projection plane perpendicular to the axis of the hub 10 forms a second projection 20a, and the orthographic projection of the axis of the hub 10 forms an axis P. A reference circle 400 is constructed around the axis P on the axial projection plane of the blade 100. The reference circle 400 is defined to intercept the outer edge of the second projection 20a to obtain a second distance L2. At the end of the blade 20 away from the hub 10 (i.e., at the bridging segment 23), the second distance L2 gradually decreases in the radial direction of the blade 100 toward the side away from the hub 10. In this way, the configuration of the outer contour of the entire blade 20 is smoother, which can reduce the resistance of the airflow flowing along the outer contour of the blade 20, thereby further reducing noise.

[0072] like Figure 6 As shown, 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 intercepting 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.

[0073] 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.

[0074] Optionally, 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 is in a range of 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 is in a range of 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 may 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 may be less than or equal to the trailing edge blade thickness of the second segment 22.

[0075] There are many specific construction methods for the hollow area 201, such as Figure 1 As shown, 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 a hollow region 201. In other words, the first segment 21, the bridging segment 23, the second segment 22, and the hub 10 collectively form an annular structure. This increases the effective length of the first segment 21 and the second segment 22, thereby improving the overall working capacity of the blade 20.

[0076] 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.

[0077] The present invention also provides 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-mentioned embodiment. Since the fan adopts all the technical solutions of all the above-mentioned embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above-mentioned embodiments, which will not be described in detail 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.

[0078] The present invention also proposes a blowing device, including a fan blade 100 or a fan. The specific structure of the fan blade 100 or the fan refers to the above embodiment. Since the present blowing device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be repeated 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 fans, the noise of the blowing device can be effectively reduced and the user experience can be improved.

[0079] The above descriptions are merely optional embodiments of the present invention and do not limit the patent scope of the present invention. All equivalent structural transformations made using the contents of the present description and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A fan blade, characterized in that: include: wheel hub; a blade assembly comprising N blades, where N is an integer greater than or equal to 2; The blade is connected to the hub, and the blade includes a first segment and a second segment, and a hollow area is defined 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 a projection plane perpendicular to the hub axis, projection points formed by orthographic projections of the blade curved surfaces do not overlap. A reference cylindrical surface is constructed around the axis of the hub, and a cross section of the blade obtained by intercepting the blade with the reference cylindrical surface is defined as a blade profile; The leading edge thickness of the airfoil of the first segment is greater than the trailing edge thickness of the airfoil 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.

2. The fan blade according to claim 1, characterized in that 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.

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

4. The fan blade according to claim 3, characterized in that The bridge segment includes a flat surface opposite the hub, the flat surface being parallel to the axis of the hub.

5. The fan blade according to claim 3, characterized in that 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.

6. The fan blade according to claim 3, characterized in that The bridging segment is arranged at an end of the blade away from the hub.

7. The fan blade according to claim 3, characterized in that 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.

8. The fan blade according to claim 3, characterized in that The inner end of the first segment and the inner end of the second segment are respectively connected to the hub, and the inner end of the first segment and the inner end of the second segment are spaced apart 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, characterized in that The first segment, the second segment and the bridge segment are integrally injection-molded; and / or, The blades and the hub are integrally injection-molded.

10. The fan blade according to claim 1, wherein: On the projection surface perpendicular to the hub axis, the hollow area is projected to form a first projection, and 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 fan blade, and the reference circle is defined to intercept the first projection to obtain a first distance L1, which is greater than 1 mm.

11. The fan blade according to claim 10, characterized in that The first distance L1 is greater than 5 mm.

12. The fan blade according to claim 1, wherein: On the projection surface perpendicular to the hub axis, the orthographic projection of the blade forms a second projection, and the orthographic projection of the hub axis forms an axis P. A reference circle is constructed around the axis P on the axial projection surface of the fan blade. 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 fan blade toward the side away from the hub.

13. The fan blade according to claim 1, wherein: The maximum thickness of the airfoil of the first segment is located in a 30% chord length region from the first leading edge line of the first segment; and / or, The maximum thickness of the airfoil of the second segment is located in a 30% chord length region from the second leading edge line of the second segment.

14. The fan blade according to claim 1, wherein: The ratio of the maximum thickness of the airfoil of the first segment to the chord length of the airfoil of the first segment is in a range of 5% to 35%; and / or, A ratio of the maximum thickness of the airfoil of the second segment to the chord length of the airfoil of the second segment ranges from 5% to 35%.

15. A fan, characterized in that: It comprises a fan blade as described in any one of claims 1 to 14, and a driving member connected to the fan blade, wherein the driving member is used to drive the fan blade to rotate.

16. A blowing device, characterized in that: It comprises the fan blade according to any one of claims 1 to 14 or the fan according to claim 15.

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