Blowing equipment

Abstract

The present invention discloses a blowing device, which comprises: a fan blade, the fan blade comprises a hub and a blade connected to the hub, the blade comprises a first segment and a second segment, at least parts of the first segment and the second segment are arranged at intervals in the circumferential and / or axial direction of the hub, and the first segment and the second segment enclose a hollow area; a reference cylindrical surface is constructed around the axis of the hub, and the cross section obtained by intercepting the blade by the reference cylindrical surface is defined as a blade profile; at least within a part of the preset height interval of the blade, the blade profile of the first segment and / or the second segment adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge. The technical solution of the present invention can effectively reduce the noise of the blowing device.

Description

Technical Field

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

[0002] Blowing equipment is widely used in people's daily life. Among them, blowing equipment using axial flow fan blades (such as floor fans) are favored by many users due to their strong wind force and wide blowing range. The blades of traditional fan blades 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, affecting the user experience. Summary of the invention

[0003] The main purpose of the present invention is to provide a blowing device, aiming to effectively reduce the noise of the blowing device.

[0004] To achieve the above object, the blowing device proposed by the present invention comprises:

[0005] A fan blade, the fan blade comprising a hub and a blade connected to the hub, the blade comprising a first segment and a second segment, at least parts of the first segment and the second segment are spaced apart in a circumferential and / or axial direction of the hub, and the first segment and the second segment enclose a hollow area;

[0006] A reference cylindrical surface is constructed around the axis of the hub, and the cross-section of the blade obtained by intercepting the reference cylindrical surface is defined as a blade profile; at least within a partial preset height range of the blade, the blade profile of the first segment and / or the second segment adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge.

[0007] In one of the embodiments, a two-dimensional rectangular coordinate system is constructed with the dimensionless mean arc line of the blade as the horizontal coordinate axis and the thickness of the blade as the vertical coordinate axis, and the horizontal coordinate of the leading edge point of the blade is defined as 0, and the horizontal coordinate of the trailing edge point of the blade is defined as 1; the horizontal coordinate corresponding to the maximum thickness Tmax1 of the leading edge of the blade is Lmax1, and the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax1 is within the range of 0 to 0.3.

[0008] In one embodiment, the preset geometric configuration satisfies that, on the transverse coordinate axis, Lmax1 is within the range of 0.05 to 0.15.

[0009] In one embodiment, the outer diameter of the fan blade is D1, and the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.01 to 0.04; and / or,

[0010] The blowing device also includes an air inlet grille, the leading edge of the blade profile faces the air inlet grille, the air inlet grille has a plurality of first grille bars arranged at intervals along the rotation direction of the fan blade, the reference cylindrical surface cuts the first grille bars to obtain a first cross-section, in the plan view unfolded from the reference cylindrical surface, the projection width formed by the axial projection of the first cross-section toward the fan blade is L1, and the preset geometric configuration satisfies that the ratio of Tmax1 to L1 is in the range of 1 to 4.

[0011] In one embodiment, the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.015 to 0.03; and the ratio of Tmax1 to L1 is in the range of 1.5 to 3.

[0012] In one of the embodiments, the horizontal coordinate corresponding to the maximum thickness Tmax2 of the trailing edge of the blade profile is Lmax2, and the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax2 is within the range of 0.7 to 1.

[0013] In one embodiment, the outer diameter of the fan blade is D1, and the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is in the range of 0 to 0.01; and / or,

[0014] The blowing device also includes an air outlet grille, the trailing edge of the blade profile faces the air outlet grille, the air outlet grille has a plurality of second grille bars arranged at intervals along the rotation direction of the fan blade, the reference cylindrical surface cuts the second grille bars to obtain a second cross-section, and in the plan view unfolded from the reference cylindrical surface, the projection width formed by the axial projection of the second cross-section toward the fan blade is L2, and the preset geometric configuration satisfies that the ratio of Tmax2 to L2 is in the range of 0 to 2.

[0015] In one embodiment, the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is in the range of 0 to 0.01; and the ratio of Tmax2 to L2 is in the range of 0 to 1.5.

[0016] In one embodiment, the blade further includes a bridging segment connecting an outer end of the first segment and an outer end of the second segment, and the first segment, the bridging segment and the second segment together define the hollow area.

[0017] In one embodiment, the blowing device also includes a mesh cover, which includes an air inlet grille and an air outlet grille, and the fan blade is rotatably arranged in the mesh cover, with the leading edge of the blade facing the air inlet grille and the trailing edge of the blade facing the air outlet grille.

[0018] In one of the embodiments, the height of the blade in the radial direction of the fan blade is H1, and the partial preset height interval is a height interval of 20% H1 to H1.

[0019] In one of the embodiments, within the entire height range of the blade, the blade profiles of the first segment and the second segment both adopt the preset geometric configuration.

[0020] The technical solution of the present invention is to construct the blade of the fan blade into an annular or quasi-annular structure, and to enclose a hollow area through 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. And at least within a part of the preset height range of the blade, the blade profile of the first segment and / or the second segment adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge. In this way, the blade profile presents the characteristics of a thick front end and a thin tail, which can effectively improve the flow field and further reduce noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0022] Figure 1 It is a structural schematic diagram of an embodiment of a blowing device of the present invention;

[0023] Figure 2 for Figure 1 Schematic diagram of the exploded structure of the screen cover of the medium-blowing device;

[0024] Figure 3 It is a structural schematic diagram of an embodiment of a fan blade of a blowing device;

[0025] Figure 4 for Figure 3 Front view of the middle fan blade;

[0026] Figure 5 for Figure 2 Schematic diagram of the structure of the middle air inlet grille;

[0027] Figure 6 for Figure 2 Schematic diagram of the structure of the middle air outlet grille;

[0028] Figure 7 The schematic diagram of using a reference cylindrical surface to intercept the mesh cover and fan blades;

[0029] Figure 8 for Figure 7 The schematic diagram of the cross section obtained by cutting the mesh cover and the fan blades with the reference cylindrical surface and unfolding them into a plane along the turning direction;

[0030] Fig. 9 A cross-sectional schematic diagram of another embodiment of a first grille bar of an air inlet grille or a second grille bar of an air outlet grille;

[0031] Fig.10 is a schematic structural diagram of a blade shape (a first blade shape or a second blade shape);

[0032] Fig.11 It is a curve diagram showing the relationship between the blade thickness and the position on the dimensionless mid-arc line;

[0033] Fig.12 A schematic diagram of the working mechanism principle of the blowing device of the present invention to achieve noise reduction;

[0034] Fig.13 A schematic structural diagram of another embodiment of a fan blade of a blowing device;

[0035] Fig.14 A schematic structural diagram of another embodiment of a fan blade of a blowing device;

[0036] Fig.15 It is a schematic structural diagram of a bridging segment of a fan blade of a blowing device according to an embodiment of the present invention;

[0037] Fig.16 It is a structural schematic diagram of a bridging segment of a fan blade of a blowing device in a comparative example;

[0038] Fig.17 This is a thickness relationship diagram between the noise of the blowing equipment and (Tmax1 / D1).

[0039] Description of Figure Numbers:

[0040] Label name Label name 100 Blowing equipment 223 Bridge Clip 10 Grille 2211 Leading edge point 10a Air intake grille 2212 Trailing edge point 11 Air intake grille 2213 First side 111 First grille bar 2214 Second side 10b Air outlet grille 2215 Middle arc 12 Air outlet grille 2211a First leading edge line 121 Second grille bar 2212a First trailing edge line 20 Fan blade 2211b Second leading edge line 201 Hollow area 2212b Second trailing edge line 21 Wheels 2213a First suction side 22 blade 2214a First pressure side 221 First Clip 2213b Second suction side 221a First leaf type 2214b Second pressure side 222 Second segment 30 Bracket 222a Second leaf type 300 Reference cylindrical surface 223’ Bridge Clip 2211a’ First leading edge line 2213a’ First suction side 2212a’ First trailing edge line 2214a’ First pressure side 2211b’ Second leading edge line 2213b’ Second suction side 2212b’ Second trailing edge line 2214b’ Second pressure side

[0041] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0042] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0043] 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 in a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0044] 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 used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of the 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 contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0045] The present invention provides a blowing device 100. The blowing device 100 includes but is not limited to fan products such as floor fans, ceiling fans, and desktop fans. The blowing device 100 can also be other devices with axial flow fan blades 20 (such as air conditioner outdoor units). The following mainly takes the blowing device 100 as a fan as an example for description.

[0046] Please refer to Figures 1 to 8In one embodiment of the present invention, the blowing device 100 includes a fan blade 20, the fan blade 20 includes a hub 21 and a blade 22 connected to the hub 21, the blade 22 includes a first segment 221 and a second segment 222, at least parts of the first segment 221 and the second segment 222 are spaced apart in the circumferential and / or axial direction of the hub 21, and the first segment 221 and the second segment 222 enclose a hollow area 201; a reference cylindrical surface 300 is constructed around the axis of the hub 21, and a cross section of the blade 22 obtained by intercepting the reference cylindrical surface 300 is defined as a blade profile; at least within a partial preset height range of the blade 22, the blade profile of the first segment 221 and / or the second segment 222 adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge.

[0047] like Figure 1 and Figure 2 As shown, the blowing device 100 may specifically include a mesh cover 10 and a fan blade 20. The mesh cover 10 includes an air inlet mesh cover 10a and an air outlet mesh cover 10b that are interlocked. The air inlet mesh cover 10a and the air outlet mesh cover 10b are enclosed to form a receiving cavity for accommodating the fan blade 20. The air inlet mesh cover 10a has an air inlet grille 11 formed by a combination of a plurality of first grille bars 111, and the air outlet mesh cover 10b has an air outlet grille 12 formed by a combination of a plurality of second grille bars 121. The fan blade 20 is rotatably arranged in the receiving cavity of the mesh cover 10. The blowing device 100 also includes a driving member connected to the air inlet mesh cover 10a, and a bracket 30 connected to the driving member. The driving member can drive the fan blade 20 to rotate, and the bracket 30 can support the blowing device 100 as a whole.

[0048] like Figure 3 , Fig.13 and Fig.14 As shown, the fan blade 20 includes a hub 21 and N blades 22 arranged on the periphery of the hub 21, wherein the number of blades 22 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 20, but also reduce the noise generated during the operation of the fan blade 20. More preferably, 4≤N≤7. The inner end (root) of the blade 22 is connected to the hub 21, and there can be many ways to connect it. For example, the blade 22 and the hub 21 can be integrally formed, or they can be assembled together by assembly structures such as screws and buckles, which are not specifically limited here.

[0049] It can be understood that at least part of the first segment 221 and the second segment 222 are spaced apart in the circumferential and / or axial direction of the hub 21, which may mean that at least part of the first segment 221 and the second segment 222 are spaced apart only in the axial direction of the hub 21, in which case the first segment 221 and the second segment 222 are arranged opposite to each other in the axial direction of the hub 21, and the corresponding hollow area 201 has a certain thickness; it may also mean that at least part of the first segment 221 and the second segment 222 are spaced apart only in the circumferential direction of the hub 21, in which case the first segment 221 and the second segment 222 are arranged opposite to each other in the circumferential direction of the hub 21, and the corresponding hollow area 201 has a certain width; it may also mean that at least part of the first segment 221 and the second segment 222 are spaced apart in both the axial and circumferential directions of the hub 21, in which case the first segment 221 and the second segment 222 are staggered on the hub 21.

[0050] The first segment 221 and the second segment 222 enclose a hollow area 201, so that the blade 22 forms an annular structure, and the hollow area 201 is the center of the annular structure. The annular structure enclosed by the first segment 221 and the second segment 222 can be either a closed annular structure or a non-closed annular structure. It should be noted that the so-called closed annular structure means that the first segment 221 and the second segment 222 are closed and connected, so that the periphery of the hollow area 201 is continuously connected without a gap. The non-closed annular structure means that the first segment 221 and the second segment 222 are at least partially not closed and connected, and some positions of the periphery of the hollow area 201 are discontinuous. For example, the first segment 221 and the second segment 222 are disconnected at one end of the top of the blade 22, but the blade 22 as a whole still presents an annular shape with a hollow area 201.

[0051] The leading edge of the blade 22 refers to the part of the blade 22 that first contacts the airflow during the rotation of the blade 20, and the trailing edge of the blade 22 refers to the part of the blade 22 where the airflow finally flows out of the blade, that is, in the air inlet direction of the blade 20, the airflow flows in from the leading edge of the blade 22 and flows out from the trailing edge of the blade 22. The pressure side of the blade 22 is the side of the blade 22 facing the impact of the airflow, and the suction side of the blade 22 is the side of the blade 22 facing away from the impact of the airflow.

[0052] It is understandable that part of the noise of the current traditional axial flow fan blades comes from the shedding vortex formed at the trailing edge of the blade when the fan blade rotates. That is, when the fan blade rotates, the airflow will form an airflow vortex at the trailing edge of the blade, and the airflow vortex will directly fall off from the trailing edge of the blade, which will produce a large noise. In the technical solution of the present invention, the blade 22 of the fan blade 20 is an annular or quasi-annular structure, and the first segment 221 and the second segment 222 of the blade 22 jointly enclose a hollow area 201, and the hollow area 201 has a certain guiding effect on the airflow on the blade 22. When the fan blade 20 rotates, the airflow at the trailing edge of the blade 22 is guided to the pressure surface of the blade 22 along the suction surface of the blade 22 through the hollow area 201. In this way, the airflow vortex at the trailing edge of the blade 20 can be dispersed to prevent the airflow vortex from directly detaching from the trailing edge of the blade 22 and generating a large shedding vortex noise.

[0053] like Figure 4 As shown, the outer diameter of the blade 20 is D1, the diameter of the hub 21 is D2; the height of the blade 22 in the radial direction of the blade 20 is H1, where H1 = (D1-D2) / 2. Figure 7 and Figure 8 As shown, a reference cylindrical surface 300 is constructed around the axis of the hub 21, and the cross section obtained by intercepting the blade 22 by the reference cylindrical surface 300 is defined as a blade profile. The blade profiles of the first segment 221 and the second segment 222 intercepted by the reference cylindrical surface 300 of the same radius are defined to belong to the same group. For the convenience of description below, the blade profile of the first segment 221 is referred to as the first blade profile 221a, and the blade profile of the second segment 222 is referred to as the second blade profile 222a. When a plurality of reference cylindrical surfaces 300 of different radii are used to intercept the blade 22 along the height direction of the blade 22 (that is, the direction from the inner end of the blade 22 to the outer end of the blade 22), a plurality of groups of blade profiles arranged within the height range of the blade 22 can be obtained. It should be noted that the inner end of the blade 22 refers to the end thereof close to the hub 21, and the outer end refers to the end thereof away from the hub 21, that is, the inner end of the blade 22 corresponds to the root portion thereof, and the outer end of the blade 22 corresponds to the tip portion thereof.

[0054] like Fig.10As shown, one of the blade profiles (the first blade profile 221a or the second blade profile 222a) of the blade 22 is taken as an example to illustrate its construction method. The blade profile has a leading edge point 2211, a trailing edge point 2212 and a center camber line 2215. The leading edge point 2211 of the blade profile refers to the intersection of the contour line of the blade profile and the leading edge of the blade 22, and the trailing edge point 2212 of the blade profile refers to the intersection of the contour line of the blade profile and the trailing edge of the blade 22. The blade profile is obtained by superimposing thicknesses T1 and T2 on the center camber line 2215. Specifically, starting from the leading edge point 2211 of the center camber line 2215 and ending at the trailing edge point 2212, two side edges of the blade profile (i.e., the first side edge 2213 and the second side edge 2214) are obtained by offsetting the distances T1 and T2 respectively along its two normal directions, wherein the sum of T1 and T2 is defined as the thickness of the blade profile. And along the direction of the center camber line 2215, the thickness of the blade profile is a variable. The maximum thickness of the leading edge of the blade refers to the thickness of the blade at the thickest part of the blade near its leading edge point 2211; the maximum thickness of the trailing edge of the blade refers to the thickness of the blade at the thickest part of the blade near its trailing edge point 2212.

[0055] At least in a part of the preset height interval of the blade 22, the blade profile of the first segment 221 and / or the second segment 222 adopts a preset geometric configuration. For example, only the first segment 221 may adopt a preset geometric configuration in a part of the preset height interval or the entire height interval of the blade 22; or only the second segment 222 may adopt a preset geometric configuration in a part of the preset height interval or the entire height interval of the blade 22. Alternatively, one of the first segment 221 and the second segment 222 adopts a preset geometric configuration in the entire height interval of the blade 22, and the other adopts a preset geometric configuration in a part of the preset height interval of the blade 22. Alternatively, both the first segment 221 and the second segment 222 adopt a preset geometric configuration in a part of the preset height interval of the blade 22. Alternatively, both the first segment 221 and the second segment 222 adopt a preset geometric configuration in the entire height interval of the blade 22. The preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge. That is, the blade profile presents the characteristics of a thick leading edge and a thin trailing edge.

[0056] Among them, the entire height interval of the blade 22 can be understood as the entire height interval from the root of the blade 22 to the tip of the blade 22. The partial preset height interval of the blade 22 can be understood as a certain preset interval within the entire height interval of the blade 22. For example, the height interval of 0 to 20% H1 can be understood as the height interval between the root of the blade 22 and the height position of 20% H1. The height interval of 20% H1 to H1 can be understood as the height interval between the height position of 20% H1 to the tip position of the blade 22. The partial preset height interval can be the height interval of 20% H1 to H1. Of course, the partial preset height interval can also be the height interval of 20% H1 to 80% H1; or other preset height intervals, etc.

[0057] The technical solution of the present invention is to construct the blade 22 of the fan blade 20 into an annular or quasi-annular structure, and to enclose a hollow area 201 by the first segment 221 and the second segment 222 of the blade 22. The hollow area 201 has a certain guiding effect on the airflow on the blade 22. When the fan blade 20 rotates, the airflow at the trailing edge of the blade 22 is guided to the pressure surface of the blade 22 along the suction surface of the blade 22 through the hollow area 201. In this way, the airflow vortex at the trailing edge of the fan blade 20 can be dispersed to prevent the airflow vortex from directly detaching from the trailing edge of the blade 22 and generating a large vortex shedding noise. And at least in a partial height range of the blade 22, the blade profile of the first segment 221 and / or the second segment 222 adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge. In this way, the blade profile presents the characteristics of a thick front end and a thin tail, which can effectively improve the flow field and further reduce noise.

[0058] like Fig.12 As shown, the blowing device 100 generally further includes a mesh cover 10, which has an air inlet grille 11 and an air outlet grille 12. After the airflow passes through the air inlet grille 11, a low-speed zone will be formed thereafter, which will interfere with the rotating impeller during the downstream transportation process, thereby generating aerodynamic noise and also causing blade flow loss. Similarly, after the airflow passes through the blade, a low-speed zone will also be formed, which will also generate strong aerodynamic noise during the interaction with the air outlet grille 12.

[0059] In order to reduce the interference between the fan blades 20 and the mesh cover 10, Figure 1 and Figure 8 As shown, in one embodiment, the blowing device 100 further includes a mesh cover 10, the mesh cover 10 includes an air inlet grille 11 and an air outlet grille 12, and the fan blade 20 is rotatably arranged in the mesh cover 10, the leading edge of the blade is facing the air inlet grille 11, and the trailing edge of the blade is facing the air outlet grille 12. In this embodiment, the front end of the blade is thicker, and the adaptability to the uneven flow at the outlet of the air inlet grille 11 is enhanced, thereby reducing aerodynamic noise and flow loss; while the tail of the blade is thinner, which can reduce the range and intensity of the low-speed area at the outlet of the blade, reduce the unevenness of the outlet speed of the blade 22, and thus reduce the interference noise with the air outlet grille 12. In this way, the interference between the fan blade 20 and the mesh cover 10 is weakened, and the noise of the blowing device 100 can be significantly reduced, and the efficiency of the whole machine can also be improved.

[0060] like Fig.11As shown, a two-dimensional rectangular coordinate system is constructed with the dimensionless mean arc line 2215 of the blade as the horizontal coordinate axis and the thickness of the blade as the vertical coordinate axis. The horizontal coordinate of the leading edge point 2211 of the blade is defined as 0, and the horizontal coordinate of the trailing edge point 2212 of the blade is defined as 1; the horizontal coordinate corresponding to the maximum thickness Tmax1 of the leading edge of the blade is Lmax1, and the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax1 is within the range of 0 to 0.3.

[0061] In this embodiment, the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax1 is within the interval of 0 to 0.3. That is, Lmax1∈[0, 0.3]. In this way, the maximum thickness position of the leading edge of the blade appears within the interval of the length of the middle camber line 2215 moving 30% from the leading edge point 2211 along the middle camber line 2215 toward the trailing edge point 2212. For example, Lmax1 can be 0, 0.1, 0.2, 0.3, or any other value between 0 and 0.3. For example, when Lmax1 is 0.1, it indicates that the maximum thickness position of the leading edge of the blade is the position at which the length of the middle camber line 2215 moves 10% from the leading edge point 2211 along the middle camber line 2215 toward the trailing edge point 2212. When Lmax1 is 0.3, it indicates that the leading edge maximum thickness position of the blade is the position when moving 30% of the length of the middle arc line 2215 from the leading edge point 2211 along the middle arc line 2215 toward the trailing edge point 2212. By optimizing the leading edge maximum thickness position of the blade, the leading edge maximum thickness position of the blade is located at a relatively forward position of the blade, which can better adapt to the uneven flow at the outlet of the air inlet grille 11, thereby being more conducive to reducing aerodynamic noise and flow loss.

[0062] Optionally, the preset geometric configuration satisfies that, on the transverse coordinate axis, Lmax1 is within the range of 0.05 to 0.15. That is, Lmax1∈[0.05, 0.15]. In this way, the maximum thickness position of the leading edge of the blade appears in the length interval between the 5% length position of the middle arc line 2215 and the 15% length position of the middle arc line 2215. In this way, the leading edge thickness of the blade changes from narrow to wide, and at the same time, the maximum thickness position of the leading edge of the blade is closer to the front, which is beneficial to improve the flow field, thereby further enhancing the adaptability to the uneven flow at the outlet of the air inlet grille 11, and further reducing aerodynamic noise and flow losses. For example, Lmax1 can be 0.05, 0.08, 0.11, 0.14, 0.15, and so on.

[0063] In one of the embodiments, the outer contour diameter of the fan blade 20 is D1, and the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.01 to 0.04. That is, Tmax1∈[0.01, 0.04]×D1, that is, 0.01≤(Tmax1 / D1)≤0.04. For example, Tmax1 can be 0.01D1, 0.02D1, 0.03D1, 0.04D1, and so on. If Tmax1 is less than 0.01D1, the maximum thickness of the leading edge of the blade is too small, and the effect of enhancing the adaptability to the uneven flow at the outlet of the air inlet grille 11 is not obvious. If Tmax1 is greater than 0.04D1, the maximum thickness of the leading edge of the blade is too large, which is not conducive to improving the flow field. By optimizing the relationship between the maximum thickness of the leading edge of the blade and the outer diameter of the blade 20, the maximum thickness of the leading edge of the blade is moderate, which can better adapt to the uneven flow at the outlet of the air inlet grille 11, thereby being more conducive to reducing aerodynamic noise and flow loss. Fig.17 The figure shows the relationship between the noise of the blowing equipment and the thickness of (Tmax1 / D1). Fig.17 It can be seen that when the maximum thickness Tmax1 of the leading edge of the blade is too large or too small, it will have a certain impact on the noise. When the range of Tmax1 / D1 is between 0.01 and 0.04, the noise is relatively low, which can achieve a good noise reduction effect.

[0064] Please refer to Figure 5 , Figures 7 to 9 In one embodiment, the blowing device 100 also includes an air inlet grille 11, the leading edge of the blade shape faces the air inlet grille 11, the air inlet grille 11 has a plurality of first grille bars 111 arranged at intervals along the rotation direction of the fan blade 20, and the first grille bars 111 are cut with reference to the cylindrical surface 300 to obtain a first cross section. In the plan view unfolded with reference to the cylindrical surface 300, the projection width formed by the axial projection of the first cross section toward the fan blade 20 is L1, and the preset geometric configuration satisfies that the ratio of Tmax1 to L1 is in the range of 1 to 4.

[0065] like Figure 7 and Figure 8 As shown, the air inlet grille 11 of the mesh cover 10 is cut by the reference cylindrical surface 300 to obtain a plurality of first cross sections, each of which is a cross section of a first grille bar 111. In the plan view of the reference cylindrical surface 300, the plurality of first cross sections are arranged in a row along the rotation direction of the fan blade 20. Each first cross section is generally a regular or irregular quadrilateral structure. For example, Figure 8 As shown, the first cross section may be a regular rectangle, so that the structure of the first grid bar 111 is simple and easy to manufacture. Fig. 9As shown, the first cross section can be a special-shaped structure, for example, the first cross section is an irregular quadrilateral structure that is wide in the front and narrow in the back, and a chamfer is formed at the corner of the quadrilateral, which is more conducive to noise reduction. Of course, the first cross section can also be other shapes, which are not specifically limited here.

[0066] The projection width formed by the axial projection of the first section toward the fan blade 20 is L1, and the preset geometric configuration satisfies that the ratio of Tmax1 to L1 is in the range of 1 to 4. That is, Tmax1∈[1,4]×L1. That is, 1≤(Tmax1 / L1)≤4. For example, Tmax1 can be L1, 2L1, 3L1, 4L1, and so on. If Tmax1 is less than L1, the maximum thickness of the leading edge of the blade is too small, and the effect of enhancing the adaptability to the uneven flow at the outlet of the air inlet grille 11 is not obvious. If Tmax1 is greater than 4L1, the maximum thickness of the leading edge of the blade is too large, which is not conducive to improving the flow field. By optimizing the relationship between the maximum thickness of the leading edge of the blade and the width dimension of the first grille bar 111 of the air inlet grille 11, the maximum thickness of the leading edge of the blade is moderate, which can better adapt to the uneven flow at the outlet of the air inlet grille 11, thereby being more conducive to reducing aerodynamic noise and flow losses.

[0067] Optionally, the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.01 to 0.04; the ratio of Tmax1 to L1 is in the range of 1 to 4. That is, Tmax1∈[0.01, 0.04]×D1, Tmax1∈[1, 4]×L1. That is, 0.01≤(Tmax1 / D1)≤0.04, 1≤(Tmax1 / L1)≤4. In this way, the maximum thickness dimension of the leading edge of the blade profile can be matched with the outer contour diameter dimension of the fan blade 20 and the width dimension of the first grille bar 111 of the air inlet grille 11 at the same time, which is beneficial to improve the flow field, can further enhance the adaptability to the uneven flow at the outlet of the air inlet grille 11, and can further reduce aerodynamic noise and flow losses.

[0068] Optionally, the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.015 to 0.03; the ratio of Tmax1 to L1 is in the range of 1.5 to 3. That is, Tmax1∈[0.015, 0.03]×D1, Tmax1∈[1.5, 3]×L1. That is, 0.015≤(Tmax1 / D1)≤0.03, 1.5≤(Tmax1 / L1)≤3. In this way, the maximum thickness dimension of the leading edge of the blade profile can better match the outer contour diameter dimension of the fan blade 20 and the width dimension of the first grille bar 111 at the same time, which is more conducive to improving the flow field, and can further enhance the adaptability to the uneven flow at the outlet of the air inlet grille 11, and can further reduce aerodynamic noise and flow losses.

[0069] like Fig.11 As shown, in one embodiment, the horizontal coordinate corresponding to the maximum thickness Tmax2 of the trailing edge of the blade is Lmax2, and the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax2 is within the range of 0.7 to 1.

[0070] In this embodiment, the preset geometric configuration satisfies that, on the transverse coordinate axis, Lmax2 is within the range of 0.7 to 1. That is, Lmax2∈[0.7, 1]. In this way, the trailing edge thickness of the blade in the length interval between 70% of the length of the mid-arc line 2215 and the trailing edge point 2212 has a peak value, and the peak value is the maximum thickness of the trailing edge of the blade. The increase in the thickness of the blade in this part is beneficial to increase the lift of the blade 22 at supersonic speed and improve the work efficiency. Of course, in some embodiments, the trailing edge thickness of the blade may also be generally consistent in the length interval between 70% of the length of the mid-arc line 2215 and the trailing edge point 2212.

[0071] In one embodiment, the outer diameter of the fan blade 20 is D1, and the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is in the range of 0 to 0.01. That is, Tmax2∈(0, 0.01]×D1. That is, 0<(Tmax2 / D1)≤0.01. For example, Tmax2 can be 0.005D1, 0.008D1, 0.01D1, and so on. In this way, the maximum thickness of the trailing edge of the blade is matched with the outer diameter of the fan blade 20, and the maximum thickness of the trailing edge is as thin as possible, which can reduce the range and strength of the low-speed zone at the outlet of the blade, reduce the unevenness of the outlet velocity of the blade 22, and thereby reduce the interference noise with the air outlet grille 12.

[0072] Please refer to Figures 6 to 9 In one embodiment, the blowing device 100 also includes an air outlet grille 12, the trailing edge of the blade shape faces the air outlet grille 12, the air outlet grille 12 has a plurality of second grille bars 121 arranged at intervals along the rotation direction of the fan blade 20, and the second grille bars 121 are cut with reference to the cylindrical surface 300 to obtain a second cross section. In the plan view unfolded with reference to the cylindrical surface 300, the projection width formed by the axial projection of the second cross section toward the fan blade 20 is L2, and the preset geometric configuration satisfies that the ratio of Tmax2 to L2 is in the range of 0 to 2.

[0073] like Figure 8As shown, the air outlet grille 12 of the mesh cover 10 is intercepted with a reference cylindrical surface 300 to obtain a plurality of second sections, and each second section is a section of a second grille bar 121. In the plan view unfolded by the reference cylindrical surface 300, the plurality of second sections are arranged in a row at intervals along the rotation direction of the fan blade 20. Each second section generally presents a regular or irregular quadrilateral structure. For example, the second section may be a regular rectangle, so that the structure of the second grille bar 121 is simple and easy to manufacture. For another example, the second section may be an irregular quadrilateral structure that is wide in the front and narrow in the back, and chamfers are formed at the corners of the quadrilateral, so that it is more conducive to the noise reduction effect. Of course, the second section may also be other shapes, which are not specifically limited here.

[0074] The projection width formed by the axial projection of the second section toward the fan blade 20 is L2, and the preset geometric configuration satisfies that the ratio of Tmax2 to L2 is in the range of 0 to 2. That is, Tmax2∈(0, 2]×L2. That is, 0<(Tmax2 / L2)≤2. For example, Tmax2 can be 0.5L2, L2, 1.5L2, 2L2, and so on. In this way, the maximum thickness of the trailing edge of the blade profile is matched with the width of the second grille bar 121 of the air outlet grille 12, and the maximum thickness of the trailing edge is made as thin as possible, which can reduce the range and strength of the low-speed zone at the outlet of the blade profile, reduce the unevenness of the outlet velocity of the blade 22, and thereby reduce the interference noise with the air outlet grille 12.

[0075] Optionally, the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is in the range of 0 to 0.01; the ratio of Tmax2 to L2 is in the range of 0 to 2. That is, Tmax2∈(0, 0.01]×D1, Tmax2∈(0, 2]×L2. That is, 0<(Tmax2 / D1)≤0.01, 0<(Tmax2 / L2)≤2. In this way, the maximum thickness dimension of the trailing edge of the blade profile can be matched with the outer contour diameter dimension of the fan blade 20 and the width of the second grille bar 121 of the air outlet grille 12 at the same time, so that the maximum thickness of the trailing edge is as thin as possible, which can further reduce the range and intensity of the low-speed zone at the blade profile outlet, and further reduce the interference noise with the air outlet grille 12.

[0076] Optionally, the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is in the range of 0 to 0.01; the ratio of Tmax2 to L2 is in the range of 0 to 1.5. That is, Tmax2∈[0, 0.01]×D1, Tmax2∈[0, 1.5]×L2. That is, 0<(Tmax2 / D1)≤0.01, 0<(Tmax2 / L2)≤1.5. In this way, the maximum thickness dimension of the leading edge of the blade profile can better match the outer contour diameter dimension of the fan blade 20 and the width dimension of the second grille bar 121 at the same time, thereby minimizing the interference noise with the air outlet grille 12 and achieving a better noise reduction effect.

[0077] It should be noted that when the first segment 221 and / or the second segment 222 adopts a preset geometric configuration, the preset geometric configuration can selectively meet the above conditions, or meet the above conditions at the same time. When the preset geometric configuration meets the above conditions at the same time, the noise reduction effect is better.

[0078] As shown in Table 1, the optimal values ​​of various parameters are given when the outer contour diameter D1 of the fan blade 20 is 300 mm.

[0079] Table 1 Optimal values ​​for diameter D1 = 300 mm

[0080] parameter Lmax1 Tmax1 Tmax2 Tmax1 / D1 Tmax2 / D1 Tmax1 / L1 Tmax2 / L2 Numeric 0.11 6mm 2.5mm 0.02 0.0083 2 0.92

[0081] like Figure 3 As shown, in one embodiment, the blade 22 further includes a bridging segment 223 , which connects the outer end of the first segment 221 and the outer end of the second segment 222 , and the first segment 221 , the bridging segment 223 and the second segment 222 together define the hollow area 201 .

[0082] In this embodiment, the first segment 221, the bridging segment 223 and the second segment 222 of the blade 22 jointly enclose a hollow area 201, and the hollow area 201 has a certain guiding effect on the airflow on the blade 22. When the fan blade 20 rotates, the airflow at the trailing edge of the blade 22 is guided along the suction surface of the blade 22 to the pressure surface of the blade 22 through the hollow area 201. In this way, the airflow vortex at the trailing edge of the blade 20 can be dispersed to prevent the airflow vortex from directly detaching from the trailing edge of the blade 22 to the outside and generating a large shedding vortex noise; on the other hand, by connecting the outer end of the first segment 221 with the outer end of the second segment 222 through the bridging segment 223, the leakage vortex at the outer end of the blade 22 can be further reduced, further reducing the noise of the fan blade 20, and on the other hand, it can also improve the working capacity of the fan blade 20.

[0083] Alternatively, if Fig.15As shown, in this embodiment, at the bridge segment 223, the leading edge line of the first segment 221 (i.e., the first leading edge line 2211a) is connected to the leading edge line of the second segment 222 (i.e., the second leading edge line 2211b), the trailing edge line of the first segment 221 (i.e., the first trailing edge line 2212a) is connected to the trailing edge line of the second segment 222 (i.e., the second trailing edge line 2212b); the pressure side of the first segment 221 (i.e., the first pressure side 2214a) is connected to the suction side of the second segment 222 (i.e., the second suction side 2213b), and the suction side of the first segment 221 (i.e., the first suction side 2213a) is connected to the pressure side of the second segment 222 (i.e., the second pressure side 2214b). By optimizing the configuration design of the bridge segment 223, the configuration of the entire blade 22 is smoother, which can play a better role in guiding airflow. For example, in the rotation direction of the fan blade 20, the first segment 221 is located upstream of the second segment 222, the outer end of the first segment 221 and the outer end of the second segment 222 are connected together by the bridge segment 223, the pressure surface of the first segment 221 is connected to the suction surface of the second segment 222 via the outer side surface of the bridge segment 223, and the suction surface of the first segment 221 is connected to the pressure surface of the second segment 222 via the inner side surface of the bridge segment 223. When the fan blade 20 rotates, the airflow vortex at the outer end of the pressure surface of the first segment 221 can flow along the outer side surface of the bridge segment 223 to the suction surface of the second segment 222, which can effectively reduce the vortex noise at the outer end of the first segment 221, and can effectively reduce the noise of the operation of the fan blade 20. The airflow vortex at the outer end of the pressure surface of the second segment 222 can be guided to the suction surface of the first segment 221 along the inner side surface of the bridge segment 223, which can effectively reduce the vortex noise at the outer end of the first segment 221, and can effectively reduce the noise of the operation of the fan blade 20.

[0084] Fig.16 3 is a schematic diagram of the structure of the bridging segment 223' in a comparative example. The structure of the bridging segment in the comparative example and the structure of the bridging segment in this embodiment adopt an opposite connection method, that is, in the comparative example, at the bridging segment 223', the leading edge line of the first segment (that is, the first leading edge line 2211a') is connected to the trailing edge line of the second segment (that is, the second trailing edge line 2212b'), the trailing edge line of the first segment (that is, the first trailing edge line 2212a') is connected to the leading edge line of the second segment (that is, the second leading edge line 2211b'), the suction side of the first segment (that is, the first suction side 2213a') is connected to the suction side of the second segment (that is, the second suction side 2213b'), and the pressure side of the first segment (that is, the first pressure side 2214a') is connected to the pressure side of the second segment (that is, the second pressure side 2214b').

[0085] The fan with the bridge segment structure of the present embodiment and the fan with the bridge structure of the comparative example were tested for performance respectively, and the performance test data were shown in Table 2. Table 2 is a performance test comparison table of the fan of the present solution and the fan of the comparative solution under the same air volume, wherein the fan blades of the fan of the present solution adopt the bridge segment structure of the present embodiment (that is, as shown in Table 2). Fig.15 The fan blades of the comparative fan adopt the bridging segment structure in the above comparative example (that is, as shown in Fig.16 The bridging fragment structure shown).

[0086] Table 2 Performance test comparison of a certain type of fan under the same air volume

[0087] plan Speed / RPM Noise / dB Power / w Fan of this solution 916 51.5 13.7 Comparison Fan 975 55.6 19.6

[0088] It can be seen from Table 2 that under the same air volume, the speed, noise and power of the fan of this solution are all lower than those of the fan of the comparative solution. That is, the use of the bridge segment structure in this embodiment can effectively reduce the fan noise while keeping the air volume unchanged, and can also reduce the fan speed and power.

[0089] Optionally, in one embodiment, a hollow ring is constructed at a portion of the bridge segment 223 away from the hub 21 on a projection plane parallel to the axis of the hub 21. In this way, a hollow ring is formed inside the bridge segment 223 near the outer edge of the blade 20, so that the air flow velocity passing through the hollow ring is higher, and the rotation speed of the blade 20 can be reduced under the condition of achieving the same air volume, thereby reducing the noise and power of the fan or blowing device 100 having the blade 20.

[0090] On the basis of the above embodiment, in one embodiment, the height of the blade 22 in the radial direction of the fan blade 20 is H1, and part of the preset height interval is the height interval of 20% H1 to H1. That is, at least in the height interval of 20% H1 to H1, the blade profile of the first segment 221 and / or the second segment 222 adopts a preset geometric configuration. In other words, at least from the height position of 20% H1 upward, the blade profile of at least one of the first segment 221 and the second segment 222 adopts a preset geometric configuration that meets the above conditions to achieve a better noise reduction effect. In the height interval below 20% H1, the blade 22 is close to the root of the blade, and other geometric configurations may be adopted.

[0091] On the basis of the above embodiments, in one embodiment, within the full height range of the blade 22, the blade profiles of the first segment 221 and the second segment 222 both adopt a preset geometric configuration. That is, within the entire height range from the root portion to the tip portion of the blade 22, the first blade profile 221a of the first segment 221 and the second blade profile 222a of the second segment 222 both present the characteristics of a thick leading edge and a thin trailing edge. The front ends of the first blade profile 221a and the second blade profile 222a are relatively thick, and the adaptability to the uneven flow at the outlet of the air inlet grille 11 is enhanced, thereby reducing aerodynamic noise and flow loss; while the tails of the first blade profile 221a and the second blade profile 222a are relatively thin, which can reduce the range and intensity of the low-speed zone at the blade profile outlet, reduce the unevenness of the outlet velocity of the blade 22, and more effectively reduce the interference noise with the air outlet grille 12. The interference between the fan blade 20 and the mesh cover 10 is greatly reduced, which can significantly reduce the noise of the blowing device 100 and also improve the efficiency of the whole machine.

[0092] In addition, there are many specific construction methods for the hollow area 201. In one embodiment, Figure 3 As shown, the inner end of the first segment 221 and the inner end of the second segment 222 are respectively connected to the hub 21, that is, at this time, the blade 22 is divided into two spaced-apart blades on the hub 21, and the first segment 221, the bridging segment 223, the second segment 222 and the hub 21 are enclosed together to form an annular structure. In this way, the effective length of the first segment 221 and the second segment 222 can be increased, thereby improving the total working capacity of the blade 22. It should be noted that the inner end of the blade 22 refers to the end close to the hub 21, and the outer end refers to the end away from the hub 21, that is, the inner end of the blade 22 corresponds to the root of the blade, and the outer end of the blade 22 corresponds to the tip of the blade.

[0093] like Fig.13 As shown, in another embodiment, the hollow area 201 can also be directly opened on the blade 22 and arranged near the outer end of the blade 22. The inner end of the second segment 222 is connected to the side edge of the first segment 221, and the inner end of the first segment 221 is connected to the hub 21. That is, the inner end of the first segment 221 serves as the root of the blade 22 and is directly connected to the hub 21, while the second segment 222 is not directly connected to the hub 21, and the end of the blade 22 away from the hub 21 is bent and circuitous toward the downstream direction of the airflow to form the hollow area 201. In this way, the root of the blade 22 can be made smaller, which is conducive to reducing the weight of the blade 22.

[0094] like Fig.14As shown, in another embodiment, the inner end of the first segment 221 is connected to the inner end of the second segment 222, and is also connected to the hub 21. That is, the root portion of the blade 22 is composed of the first segment 221 and the second segment 222 at the same time, and the hollow area 201 is directly opened on the blade 22. In this way, the structural strength of the root portion of the blade 22 can be improved. In the rotation direction of the fan blade 20, the first segment 221 is located upstream of the second segment 222. When the fan blade 20 rotates, most of the airflow can be directly blown out positively by the pressure surface of the first segment 221 and the second segment 222. At the same time, the airflow vortex on the suction surface of the first segment 221 can flow to the pressure surface of the second segment 222, so that the airflow vortex at the trailing edge of the first segment 221 can be absorbed by the second segment 222, reducing the direct shedding of the airflow vortex at the trailing edge of the first segment 221 and generating a large noise, thereby effectively reducing the noise of the fan blade 20.

[0095] 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 blowing device, characterized in that: include: A fan blade, the fan blade comprising a hub and a blade connected to the hub, the blade comprising a first segment and a second segment, at least parts of the first segment and the second segment are spaced apart in a circumferential and / or axial direction of the hub, and the first segment and the second segment enclose a hollow area; 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; at least in a part of the preset height range of the blade, the blade profile of the first segment and / or the second segment adopts a preset geometric configuration, and the preset geometric configuration satisfies that the maximum thickness of the leading edge of the blade profile is greater than the maximum thickness of the trailing edge; A two-dimensional rectangular coordinate system is constructed with the dimensionless mean arc line of the blade as the horizontal coordinate axis and the thickness of the blade as the vertical coordinate axis, and the horizontal coordinate of the leading edge point of the blade is defined as 0, and the horizontal coordinate of the trailing edge point of the blade is defined as 1; the horizontal coordinate corresponding to the maximum thickness Tmax1 of the leading edge of the blade is Lmax1, the outer contour diameter of the fan blade is D1, and the preset geometric configuration satisfies that the ratio of Tmax1 to D1 is in the range of 0.01 to 0.

04.

2. The blowing device according to claim 1, characterized in that The preset geometric configuration satisfies that, on the transverse coordinate axis, Lmax1 is within the interval range of 0 to 0.

3.

3. The blowing device according to claim 2, characterized in that The preset geometric configuration satisfies that, on the transverse coordinate axis, Lmax1 is within the interval range of 0.05 to 0.

15.

4. The blowing device according to claim 2, characterized in that: The blowing device also includes an air inlet grille, the leading edge of the blade profile faces the air inlet grille, the air inlet grille has a plurality of first grille bars arranged at intervals along the rotation direction of the fan blade, the reference cylindrical surface cuts the first grille bars to obtain a first cross-section, in the plan view unfolded from the reference cylindrical surface, the projection width formed by the axial projection of the first cross-section toward the fan blade is L1, and the preset geometric configuration satisfies that the ratio of Tmax1 to L1 is in the range of 1 to 4.

5. The blowing device according to claim 4, characterized in that The preset geometric configuration satisfies that the ratio of Tmax1 to D1 is within the range of 0.015 to 0.03; and the ratio of Tmax1 to L1 is within the range of 1.5 to 3.

6. The blowing device according to claim 2, characterized in that The horizontal coordinate corresponding to the maximum thickness Tmax2 of the trailing edge of the blade profile is Lmax2, and the preset geometric configuration satisfies that, on the horizontal coordinate axis, Lmax2 is within the range of 0.7 to 1.

7. The blowing device according to claim 6, characterized in that The outer diameter of the fan blade is D1, and the preset geometric configuration satisfies that the ratio of Tmax2 to D1 is within the range of 0 to 0.01; and / or, The blowing device also includes an air outlet grille, the trailing edge of the blade profile faces the air outlet grille, the air outlet grille has a plurality of second grille bars arranged at intervals along the rotation direction of the fan blade, the reference cylindrical surface cuts the second grille bars to obtain a second cross-section, and in the plan view unfolded from the reference cylindrical surface, the projection width formed by the axial projection of the second cross-section toward the fan blade is L2, and the preset geometric configuration satisfies that the ratio of Tmax2 to L2 is in the range of 0 to 2.

8. The blowing device according to claim 7, characterized in that The preset geometric configuration satisfies that the ratio of Tmax2 to D1 is within the range of 0 to 0.01; and the ratio of Tmax2 to L2 is within the range of 0 to 1.

5.

9. The blowing device according to claim 1, characterized in that: The blade further includes a bridge segment connecting an outer end of the first segment and an outer end of the second segment, the first segment, the bridge segment and the second segment together defining the hollow area.

10. The blowing device according to claim 1, characterized in that The blowing device also includes a mesh cover, which includes an air inlet grille and an air outlet grille. The fan blade is rotatably arranged in the mesh cover, with the leading edge of the blade facing the air inlet grille and the trailing edge of the blade facing the air outlet grille.

11. The blowing device according to any one of claims 1 to 10, characterized in that: The height of the blade in the radial direction of the fan blade is H1, and the partial preset height interval is a height interval of 20% H1 to H1.

12. The blowing device according to any one of claims 1 to 10, characterized in that: In the entire height range of the blade, the blade profiles of the first segment and the second segment both adopt the preset geometric configuration.

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