Fan blade, fan and blowing device

Abstract

The present invention discloses a fan blade, a fan, and a blowing device. The fan blade includes a hub and a blade assembly. The blade assembly includes N blades, where N is an integer greater than or equal to 2. The blades are connected to the hub. 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. This technical solution can reduce the operating noise of the fan blade, reduce the mold opening difficulty during the injection molding of the fan blade, and facilitate production and manufacturing.

Description

Technical Field

[0001] The present invention relates to the technical field of blowing devices, and particularly to a fan blade, a fan, and a blowing device. Background Art

[0002] Blowing devices are widely used in people's daily lives. Among them, blowing devices using axial fan blades (such as floor fans) are favored by many users because of their large wind force and wide blowing range. The blades of traditional fan blades generally adopt simple straight plate or arc plate structures. When the blowing device is set to a larger gear, the noise is often relatively large, which will cause certain troubles to users. In order to reduce the noise of the fan, more complex shape designs need to be made for the blades. However, this will lead to difficulties in mold opening during the injection molding of the fan blades, increasing the manufacturing difficulty of the fan blades. Summary of the Invention

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

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

[0005] A hub;

[0006] 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;

[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 plane perpendicular to the axis of the hub, the projection points formed by the orthographic projection of the blade surface do not overlap.

[0008] In one embodiment, on the projection plane perpendicular to the axis of the hub, there is no overlap between the projection planes formed by the orthographic projections of the N blades of the blade assembly.

[0009] In one embodiment, 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.

[0010] In one embodiment, the bridging segment includes a plane opposite to the hub, and the plane 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 not greater than 5% * H1.

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

[0013] In one embodiment, at 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.

[0014] In one embodiment, the inner ends of the first segment and the second segment are respectively connected to the hub, and the inner ends of the first segment and the second segment have a gap in the circumferential direction of the fan blade. The first segment, the bridging segment, the second segment, and the hub jointly define the hollow region.

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

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

[0017] In one embodiment, on a projection plane parallel to the axis of the hub, the orthographic projection formed by the end of the blade away from the hub has a hollow ring.

[0018] In one embodiment, on a projection plane perpendicular to the axis of the hub, the orthographic projection of the hollow region forms a first projection, the orthographic projection of the axis of the hub forms a center P, a reference circle is configured on the axial projection plane of the fan blade around the center P, and a first distance L1 is defined as the reference circle intercepting the first projection. 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 axis of the hub, the orthographic projection of the blade forms a second projection, the orthographic projection of the axis of the hub forms a center P, a reference circle is configured on the axial projection plane of the fan blade around the center P, and a second distance L2 is defined as the reference circle intercepting the outer edge of the second projection. 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.

[0021] In one embodiment, 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;

[0022] The thickness of the leading edge of the airfoil of the first segment is greater than the thickness of the trailing edge of the airfoil 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.

[0023] The present invention further provides a fan, including the fan blade as described above, and a driving member connected to the fan blade, where the driving member is used to drive the fan blade to rotate.

[0024] The present invention further provides a blowing device, including the fan blade or the fan as described above.

[0025] In the technical solution of the present invention, there is a hollow area between the first segment and the second segment of the blade. This hollow area has a certain guiding effect on the air flow on the blade. When the fan blade rotates, the air flow at the trailing edge of the blade is guided along the suction surface of the blade to the pressure surface of the blade through this hollow area. In this way, the air flow vortices at the trailing edge of the fan blade can be dispersed, avoiding the large shedding vortex noise caused by the direct detachment of the air flow vortices from the trailing edge of the blade. And on the projection plane perpendicular to the hub axis, there is no overlap of the projection points formed by the orthographic projection of the entire blade surface, which greatly reduces the mold opening difficulty of the annular blade and is 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 mold opening difficulty during the injection molding of the fan blade, facilitating production and manufacturing. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on the structures shown in these drawings.

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

[0028] Figure 2 is Figure 1 the front view of the fan blade in

[0029] Figure 3 is Figure 1 the projection view of the fan blade in

[0030] Figure 4 a schematic diagram of a set of airfoils formed by the intersection of a blade of the fan blade and a reference cylindrical surface;

[0031] Figure 5Schematic diagram of a plurality of sets of blade profiles formed by the intersection of one blade of the fan blade with multiple different reference cylindrical surfaces;

[0032] Figure 6 is Figure 5 Schematic diagram of the structure of the same set of blade profiles after being unfolded into a planar state in

[0033] Figure 7 is Figure 5 Schematic diagram of the structure of the bridging segment of the blade in

[0034] Figure 8 is Figure 7 Schematic diagram of the structure of the bridging segment from another perspective in

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

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

[0037] Explanation of the reference numerals in the drawings:

[0038] Reference numeral Name Reference numeral Name 100 Fan blade 22 Second segment 10 Hub 221a Second leading edge point 20 Vane 222b Second trailing edge point 201 Hollow region 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

[0039] The realization of the object of the present invention, functional features and advantages will be further described in conjunction with the embodiments with reference to the drawings. Detailed implementation manners

[0040] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0041] It should be noted that if there are directional indications (such as up, down, left, right, front, back...) involved in the embodiments of the present invention, the directional indications are only used to explain the relative position relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0042] In addition, if the embodiments of the present invention involve descriptions such as "first", "second", etc., the descriptions of "first", "second", etc. are only for descriptive purposes and should not be construed as indicating or implying their relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel scenarios. Taking "A and / or B" as an example, it includes scenario A, or scenario B, or the scenario where both A and B are satisfied simultaneously. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the ability of those of ordinary skill in the art to implement. When the combination of technical solutions results in contradictions or inability to implement, it should be considered 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 an embodiment of the present invention, the fan blade 100 includes:

[0045] A hub 10;

[0046] A blade assembly, including N blades 20, where N is an integer greater than or equal to 2; the blades 20 are connected to the hub 10. The blade 20 includes a first segment 21 and a second segment 22, and there is 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 entire blade 20 surface do not overlap.

[0047] The fan blade 100 includes a hub 10 and N blades 20 provided on the outer periphery of the hub 10. The number of the blades 20 can be set according to actual needs, 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 various connection methods. For example, the blade 20 and the hub 10 can be integrally formed, or they can also be assembled together through assembly structures such as screws and buckles, which are not specifically limited herein. In some embodiments, the blade 20 may further include a bridging segment 23 connected between a first segment 21 and a second segment 22. There are various forming methods for 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 separately formed and then spliced, which are not specifically limited herein. 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, the stability is better, and at the same time, the manufacturing process of the blade 20 can be simplified. Optionally, the blade 20 and the hub 10 are integrally injection-molded, so that the connection part between the blade 20 and the hub 10 is more stable and reliable, and at the same time, the manufacturing process of the fan blade 100 can be simplified.

[0048] Optionally, at least part 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 can be understood that at least part of the first segment 21 and the second segment 22 being spaced apart in the circumferential and / or axial directions of the hub 10 can mean that at least part of the first segment 21 and the second segment 22 are only spaced apart along the axial direction of the hub 10. At this time, the first segment 21 and the second segment 22 are axially opposite to each other on the hub 10, and the corresponding hollow region 201 has a certain thickness. It can also mean that at least part of the first segment 21 and the second segment 22 are only spaced apart along the circumferential direction of the hub 10. At this time, the first segment 21 and the second segment 22 are circumferentially opposite to each other on the hub 10, and the corresponding hollow region 201 has a certain width. It can also be that at least part of the first segment 21 and the second segment 22 are spaced apart along both the axial and circumferential directions of the hub 10. At this time, the first segment 21 and the second segment 22 are misaligned on the hub 10.

[0049] It should be noted that the inner end of the blade 20 refers to the end close to the hub 10, and the outer end refers to the end far from the hub 10. That is to say, the inner end of the blade 20 corresponds to its root part, and the outer end of the blade 20 corresponds to its tip part. The leading edge of the blade 20 refers to the part 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 part 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 into the blade 20 from the leading edge 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 airflow direction faced by 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 that the airflow turns away from.

[0050] It can be understood that for the current traditional axial-flow fan blades, part of the noise comes from the shedding vortices formed at the trailing edge of the blades during the rotation of the fan blades. That is, when the fan blades rotate, the airflow will form airflow vortices at the trailing edge of the blades, and the direct shedding of the airflow vortices from the trailing edge of the blades will generate relatively large noise. In the technical solution of the present invention, a hollow region 201 is jointly enclosed by the first segment 21, the bridging segment 23 and the second segment 22 of the blade 20. The 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 vortices at the trailing edge of the fan blade 100 can be dispersed, avoiding the generation of relatively large shedding vortex noise due to the direct outward detachment of the airflow vortices from the trailing edge of the blade 20; on the other hand, by connecting the outer end of the first segment 21 and the outer end of the second segment 22 through the bridging segment 23, the leakage vortices at the outer end of the blade 20 can be further reduced, further reducing the noise of the fan blade 100 and improving the work capacity of the fan blade 100 on the other hand.

[0051] 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 surface do not overlap. It should be understood that, without affecting the smooth mold opening, the projection points of the entire blade surface are basically non-overlapping. In actual applications, due to certain manufacturing errors in the production process of the fan blade 100, there may be a situation where some projection points of the entire blade 20 surface overlap. For example, as long as the area occupied by all the overlapping points of the blade surface does not exceed 5% of the projection area of the entire blade 20 surface, it can be regarded as basically non-overlapping.

[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 air flow on the blade 20. When the fan blade 100 rotates, the air flow 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 this hollow region 201. In this way, the air flow vortices at the trailing edge of the fan blade 100 can be dispersed, preventing the air flow vortices from directly separating outward from the trailing edge of the blade 20 and generating a large shedding vortex noise. On the other hand, by connecting the outer end of the first segment 21 to the outer end of the second segment 22 through the bridging segment 23, the leakage vortices at the outer end of the blade 20 can be further reduced, further lowering the noise of the fan blade 100 and also improving the work - doing ability of the fan blade 100. And 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 surface do not overlap, greatly reducing the mold - opening difficulty of the annular blade 20 and being 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 100, and at the same time can reduce the mold - opening difficulty during the injection molding of the fan blade 100, facilitating production and manufacturing.

[0053] In one embodiment, on the projection plane perpendicular to the axis of the hub 10, there is no overlap in the projections of the N blades 20 of the blade assembly. In this way, the smooth mold - opening of the entire fan blade 100 and each blade 20 can be ensured.

[0054] In one of the embodiments, the blade 20 further includes a bridging segment 23. The bridging segment 23 connects the ends of the first segment 21 and the second segment 22 that are far from the hub 10, and the hollow region 201 is enclosed between the first segment 21, the bridging segment 23, and the second segment 22.

[0055] That the first segment 21, the bridging segment 23, and the second segment 22 jointly enclose the hollow region 201 means that the first segment 21, the bridging segment 23, and the second segment 22 jointly enclose a ring - shaped structure, and the hollow region 201 is the center of this ring - shaped structure. This ring - shaped structure can be either a closed ring or a non - closed ring. For example, the first segment 21, the bridging segment 23, and the second segment 22 are connected end to end in sequence, and the three jointly enclose a closed ring - shaped structure; or for another example, the first segment 21, the bridging segment 23, and the second segment 22 are connected in sequence, and there is a gap between the inner ends of the first segment 21 and the second segment 22 and they are respectively connected to the hub 10. At this time, the first segment 21, the bridging segment 23, and the second segment 22 jointly enclose a non - closed ring - shaped structure, but the first segment 21, the bridging segment 23, the second segment 22, and the hub 10 jointly enclose a closed ring - shaped structure.

[0056] In order 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 being parallel to the axis of the hub 10 should be understood as that, without affecting 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 (for example, the angle can be 1° - 5°, or other values as long as it does not affect mold opening) is allowed between the plane 232 of the bridging segment 23 and the axis of the hub 10. Of course, it can also be that the plane 232 of the bridging segment 23 is parallel to the axis of the hub 10.

[0057] As Figure 3 and Figure 5 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 bridging segment 23 in the axial direction of the fan blade 100 is L0, where L0 is not greater than 5% * H1. That is, L0 ≤ 5% * H1. In this way, the width of the bridging 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; among them,

[0058] Furthermore, the bridging segment 23 is arranged at one end of the blade 20 away from the hub 10. That is, the bridging segment 23 can be arranged as far away from the hub 10 as possible. In this way, the interference with the mainstream of the air flow inhaled by the blade 20 can be reduced.

[0059] Since the technical solution optimizes the structure of the fan blade 100, it can reduce the mold opening difficulty during its 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, making the overall structural strength of the blade 20 higher and the stability better. At the same time, it can also simplify the manufacturing process of the blade 20. Optionally, the blade 20 and the hub 10 are integrally injection molded, making the connection part between the blade 20 and the hub 10 more stable and reliable. At the same time, it can also simplify the manufacturing process of the fan blade 100. It is worth noting that although the structure of the fan blade 100 in this technical solution is more suitable for the integral injection molding process, in actual applications, other molding methods (such as 3D printing) can also be used for production and manufacturing, which are all within the protection scope 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] AsFigure 4 As shown, a reference cylindrical surface 300 is configured around the axis of the hub 10, and the cross-section obtained by the reference cylindrical surface 300 intercepting the blade 20 is defined as the airfoil; it is defined that the airfoils of the first segment 21 and the second segment 22 intercepted by the reference cylindrical surfaces 300 with the same radius belong to the same group. Figure 5 A total of 4 groups of airfoils intercepted by 4 reference cylindrical surfaces 300 with different radii are shown, including airfoil 21a and airfoil 22a, airfoil 21b and airfoil 22b, airfoil 21c and airfoil 22c, airfoil 21d and airfoil 22d. Among them, the airfoil 21a and the airfoil 22a belonging to the same group are located at the root part of the blade 20, and the other 3 groups of airfoils are sequentially spaced along the direction close to the blade tip.

[0062] Please combine Figure 5 and Figure 6 , and expand one group of airfoils (such as airfoil 21c and airfoil 22c) into a planar state along the circumferential direction. In the rotation direction of the fan blade 100, the airfoil of the first segment 21 (such as airfoil 21c) is located upstream of the airfoil of the second segment 22 (such as airfoil 22c). The airfoil of the first segment 21 (such as airfoil 21c) has a first leading edge point 211a and a first trailing edge point 212b. In the rotation direction of the fan blade 100, the first leading edge point 211a is located upstream of the first trailing edge point 212b. Connect the first leading edge points 211a of multiple airfoils of the first segment 21 (such as 21a, 21b, 21c, 21d, etc.) in sequence to form a first leading edge line 211, and connect the first trailing edge points 212b of multiple airfoils of the first segment 21 (such as 21a, 21b, 21c, 21d, etc.) in sequence to form a first trailing edge line 212; the first leading edge line 211 and the first trailing edge line 212 extend to the bridging segment 23. The airfoil of the second segment 22 (such as airfoil 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. Connect the second leading edge points 221a of multiple airfoils of the second segment 22 (such as 22a, 22b, 22c, 22d, etc.) in sequence to form a second leading edge line 221, and connect the second trailing edge points 222b of multiple airfoils of the second segment 22 (such as 22a, 22b, 22c, 22d, etc.) 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] As Figure 6As shown, at the first leading edge point 211a and the first trailing edge point 212b, the airfoil of the first segment 21 (such as airfoil 21c) is separated to obtain two side profiles. The side of the airfoil of the first segment 21 close to the rotation direction of the fan blade 100 is defined as the first pressure side 213, and the other side is the first suction side 214. At the second leading edge point 221a and the second trailing edge point 222b, the airfoil of the second segment 22 (such as airfoil 22c) is separated to obtain two side profiles. The side of the airfoil of the second segment 22 close to the rotation direction of the fan blade 100 is defined as the second pressure side 223, and the other side is the second suction side 224. Then, the profiles of the first pressure side 213 of the multiple airfoils of the first segment 21 are stacked to form the pressure surface of the first segment 21, and the profiles of the first suction side 214 of the multiple airfoils are stacked to form the suction surface of the first segment 21. The profiles of the second pressure side 223 of the multiple airfoils of the second segment 22 are stacked to form the pressure surface of the second segment 22, and the profiles of the second suction side 224 of the multiple airfoils are stacked to form the suction surface of the second segment 22. It can be understood that the pressure surface of the blade 20 is the side of the blade 20 facing the airflow impact, and the suction surface of the blade 20 refers to the side of the blade 20 facing away from the airflow impact.

[0064] As Figure 7 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, through the optimized design of the configuration of the bridging segment 23, the configuration of the entire blade 20 is made more smooth, which can play a better role in guiding the airflow. For example, in the rotation direction of the fan blade 100, the first segment 21 is located upstream of the second segment 22. The outer ends of the first segment 21 and the second segment 22 are connected by the bridging 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 bridging 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 bridging segment 23. When the fan blade 100 rotates, the airflow vortex at the outer end part of the pressure surface of the first segment 21 can flow along the outer side surface of the bridging 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 can effectively reduce the noise of the operation of the fan blade 100. The airflow vortex at the outer end of the pressure surface of the second segment 22 can be guided along the inner side surface of the bridging segment 23 to the suction surface of the first segment 21, which can effectively reduce the shedding vortex noise at the outer end of the first segment 21 and can effectively reduce the noise of the operation of the fan blade 100.

[0066] Figure 9FIG. 0 is a schematic structural view 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 position of the bridging segment 23', the leading edge line of the first segment (i.e., the first leading edge line 211') is connected to the trailing edge line of the second segment (i.e., the second trailing edge line 222'), the trailing edge line of the first segment (i.e., the first trailing edge line 212') is connected to the leading edge line of the second segment (i.e., the second leading edge line 221'), the suction side of the first segment (i.e., the first suction side 214') is connected to the suction side of the second segment (i.e., the second suction side 224'), and the pressure side of the first segment (i.e., the first pressure side 213') is connected to the pressure side of the second segment (i.e., the second pressure side 214').

[0067] Performance tests were respectively carried out on the fan with the bridging segment structure of this embodiment (referred to as this solution) and the fan with the bridging structure of the above comparative example (referred to as the comparative example). Under the same size of the fan blades and the same air volume, the noise of this solution is at least 3 dB lower than that of the comparative example. It can be seen that adopting the bridging segment structure in this embodiment can effectively reduce the fan noise under the condition of unchanged air volume.

[0068] Optionally, at the bridging segment 23, the first leading edge line 211 and the second leading edge line 221 have a smooth transition, the first trailing edge line 212 and the second trailing edge line 222 have a smooth transition, the pressure side of the first segment 21 and the suction surface of the second segment 22 have a smooth transition, and the suction surface of the first segment 21 and the pressure side of the second segment 22 have a smooth transition. In this way, the flow field of the blade 20 in the hollow region 201, especially at the tip part, can be optimized, which is beneficial to maintaining the shape of the hollow region 201. At the same time, it can also make the connection parts of each segment smoother, avoid generating undercuts, thereby further reducing the mold opening difficulty when the blade 20 is injection molded, and is beneficial to further reducing the manufacturing difficulty of the fan blade 100.

[0069] As Figure 8 and Figure 10 shown, in some embodiments, on the projection plane parallel to the axis of the hub 10, the orthographic projection formed by the end of the blade 20 far from the hub 10 (such as the position of the bridging segment 23) has a hollow ring 231. In this way, the air flow velocity passing through the hollow ring 231 is relatively high, and the rotational speed of the fan blade 100 can be reduced under the condition of the same air volume, so that the noise and power of the fan or the blowing device with the fan blade 100 are reduced.

[0070] As Figure 2As shown, in one embodiment, on the projection plane perpendicular to the axis of the hub 10, the hollow region 201 forms a first projection 201a in the orthographic projection. The axis of the hub 10 forms the center P in the orthographic projection. A reference circle 400 is configured on the axial projection plane of the fan blade 100 around the center P. It is defined that the reference circle 400 intercepts the first projection 201a to obtain a first distance L1, and the first distance L1 is greater than 1 mm. This can further ensure that the projection points formed by the curved surface of the blade 20 on the axial projection plane of the fan blade 100 do not overlap, greatly reducing the mold opening difficulty of the annular blade 20 and being more conducive to production and manufacturing 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] As Figure 2 shown, in one embodiment, on the projection plane perpendicular to the axis of the hub 10, the blade 20 forms a second projection 20a in the orthographic projection. The axis of the hub 10 forms the center P in the orthographic projection. A reference circle 400 is configured on the axial projection plane of the fan blade 100 around the center P. It is defined that the reference circle 400 intercepts the outer edge of the second projection 20a to obtain a second distance L2. At the end of the blade 20 far from the hub 10 (i.e., at the bridging segment 23), the second distance L2 gradually decreases in the radial direction of the fan blade 100 towards the side away from the hub 10. In this way, the configuration of the outer contour of the entire blade 20 is smoother, the resistance of the airflow flowing along the outer contour of the blade 20 can be reduced, and thus the noise can be further reduced.

[0072] As Figure 6 shown, in some embodiments, a reference cylindrical surface 300 is configured around the axis of the hub 10. The cross-section obtained by the reference cylindrical surface 300 intercepting the blade 20 is defined as the blade profile; the leading-edge thickness of the blade profile of the first segment 21 is greater than the trailing-edge thickness of the blade profile of the first segment 21; and / or, the leading-edge thickness of the blade profile of the second segment 22 is greater than the trailing-edge thickness of the blade profile of the second segment 22. It should be noted that the thickness dimension of the blade profile refers to the width dimension of the blade profile in the direction perpendicular to its mean camber line.

[0073] With such a setting, the leading-edge profile of the first segment 21 and / or the second segment 22 is relatively thick, while the trailing-edge profile is relatively thin. That is, the profile is thick at the leading edge and thin at the trailing edge, which is beneficial to improving the flow field on the first segment 21 and the second segment 22, and further reducing the aerodynamic noise of the fan blade 100. In addition, in practical applications, some fan blades 100 are installed inside the grille. The interference between the grille and the fan blade 100 is strong, which will generate relatively large noise. In this technical solution, the leading-edge profile of the first segment 21 and / or the second segment 22 is relatively thick, enhancing the adaptability to the uneven flow at the outlet of the inlet grille; while the trailing-edge profile of the first segment 21 and / or the second segment 22 is relatively thin, which can reduce the unevenness of the outlet velocity of the blade 20 and weaken the interference with the grille. Thus, due to the weakened interference between the fan blade 100 and the inlet and outlet grilles, the noise of the fan can be significantly reduced, and at the same time, the overall efficiency of the machine can also be improved.

[0074] Optionally, the maximum thickness of the profile of the first segment 21 is located within the 30% chord length region starting from the first leading-edge line 211, and the ratio of the maximum thickness of the profile to the chord length of the profile ranges from 5% to 35%; the maximum thickness of the profile of the second segment 22 is located within the 30% chord length region starting from the second leading-edge line 221, and the ratio of the maximum thickness of the profile to the chord length of the profile ranges from 5% to 35%. In this way, the leading edges of the first segment 21 and the second segment 22 can effectively resist the intake distortion and generate a relatively weak wake low-speed region, thereby further reducing the aerodynamic noise of the fan blade 100. Of course, in other embodiments, it may also be that the leading-edge profile thickness of the first segment 21 is less than or equal to the trailing-edge profile thickness of the first segment 21; and / or the leading-edge profile thickness of the second segment 22 is less than or equal to the trailing-edge profile thickness of the second segment 22.

[0075] And there are various specific structural forms for the hollow region 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 have a gap in the circumferential direction of the fan blade 100. The first segment 21, the bridging segment 23, the second segment 22, and the hub 10 jointly define the hollow region 201. That is, at this time, the first segment 21, the bridging segment 23, the second segment 22, and the hub 10 jointly enclose to form an annular structure. In this way, the effective lengths of the first segment 21 and the second segment 22 can be increased, thereby enhancing the total work 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, that is, the end of the blade 20 away from the hub 10 is bent and circuitous in the direction opposite to the rotation direction of the fan blade 100 to form a hollow area 201. In this way, the root of the blade 20 can be made smaller, which is conducive to reducing 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 composed of the first segment 21 and the second segment 22 at the same time, and the hollow area 201 is directly opened on the blade 20. In this way, the structural strength of the root of the blade 20 can be improved. In addition, in some embodiments, a filter net may be provided in the hollow area 201 to also play a role in filtering and purifying.

[0077] The present invention 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 by the technical solutions of the above embodiments, which will not be described one by one here. Among them, the fan can specifically be an axial flow fan with axial flow fan blades 100, and the driving member can be any one of a 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 blowing device adopts all the technical solutions of all the above embodiments, it at least has all the beneficial effects brought 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 only optional embodiments of the present invention, and are not intended to limit the patent scope of the present invention. All equivalent structural changes made using the contents of the present invention's specification and drawings, or directly / indirectly applied in other related technical fields, are included in the patent protection scope of the present invention.

Claims

1. A fan blade, characterized in that, Comprising: A hub; A blade assembly including N blades, where N is an integer greater than or equal to 2; The blades are connected to the hub. The blade includes a first segment and a second segment, and there is a hollow region 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 have no overlap; 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.

2. The fan blade according to claim 1, characterized in that, On the projection plane perpendicular to the axis of the hub, there is no overlap between the projection planes formed by the 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 that connects the ends of the first segment and the second segment away from the hub, and the hollow region is defined by enclosing 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 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 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 blade according to claim 3, characterized in that, 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 region.

9. The fan blade according to claim 3, characterized in that, 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 perpendicular to the axis of the hub, the orthographic projection of the hollow region 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 reference circle intercepting the first projection. The first distance L1 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 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 reference circle intercepting the outer edge of the second projection. 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.

13. The fan blade according to any one of claims 1 to 12, characterized in that, 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 blade profile of the second segment is greater than the thickness of the trailing edge of the blade profile of the second segment.

14. A fan, characterized in that, Comprising a fan blade according to any one of claims 1 to 13, and a driving member connected to the fan blade, the driving member being configured to drive the fan blade to rotate.

15. A blowing device, characterized in that, Comprising a fan blade according to any one of claims 1 to 13 or a fan according to claim 14.

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