Axial fan blade structure and axial fan

Abstract

The application provides an axial fan blade structure and an axial fan, which comprise a hub, a blade and a blade ring, and are characterized in that: the root and the tip of the blade are connected with the hub and the blade ring respectively, and an air guide cavity is formed below the blade; the normal projection of the connecting end of the blade and the hub forms a surface one, the normal projection of the connecting end of the blade and the blade ring forms a surface two, and the air inlet ends of the surface one and the surface two are both inclined upward; the blade is deflected from the root to the tip in a gentle trend, so that the inclination angle of the surface two is smaller than that of the surface one; the air inlet end of the blade is provided with a horizontally bent blade surface one, and the blade surface one is connected with the blade ring. The application solves the problems of ensuring sufficient air volume and improving noise under the requirement of high static pressure of the axial fan.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of axial flow fans, and particularly relates to an axial fan blade structure and an axial flow fan. BACKGROUND

[0002] The continuous development of new energy buses, trucks and engineering machinery also drives the product and technological innovation in the field of heat dissipation. As a necessary part of the automobile cooling system, the high service life, low noise and high performance of the axial heat dissipation fan have become the primary choice of the heat dissipation system of new energy vehicles.

[0003] At present, in the design and manufacturing process of the axial heat dissipation fan, it is often difficult to achieve the best axial fan scheme. Some have good heat dissipation performance but high noise, and some have high speed but cannot meet the balance performance requirements. After a long time of use, the balance of the fan blade is affected by dust accumulation, which reduces the service life of the motor.

[0004] At the same time, the heat dissipation requirement is getting higher and higher, the static pressure is getting larger, and the air volume requirement is also getting larger. Since the static pressure and the air volume are mutually restricted, the larger the air volume is, the larger the noise is. For example, the static pressure is required to increase from the conventional 100-200 Pa to 250-350 Pa, which poses a greater challenge to the air volume and noise reduction of the heat dissipation fan. SUMMARY

[0005] The purpose of the application is to provide an axial fan blade structure and an axial flow fan to solve the problem of ensuring sufficient air volume and improving noise under the requirement of high static pressure of the axial flow fan.

[0006] The application provides the following technical scheme:

[0007] An axial fan blade structure comprises a hub, a blade and a blade ring, the root and tip of the blade are connected with the hub and the blade ring respectively to form an air guide cavity;

[0008] The normal projection of the connecting end of the blade and the hub forms a surface one, the normal projection of the connecting end of the blade and the blade ring forms a surface two, the air inlet end of the surface one and the surface two are both inclined upward, the blade is deflected from the root to the tip in a gentle trend, and the inclination angle of the surface two is smaller than that of the surface one;

[0009] The air inlet end of the blade is provided with a horizontally bent blade surface one, and the blade surface one is connected with the blade ring.

[0010] Preferably, the normal projection of the surface one and the surface two intersect with each other, the top end of the surface two is lower than that of the surface one, and the bottom end of the surface two is higher than that of the surface one.

[0011] Preferably, the blade further comprises integrally formed blade surface two and blade surface three, which are connected to the hub and the ring respectively, the angle between the wind inlet end of the blade surface two and the side wall of the hub is angle one, the angle between the wind inlet end of the blade surface three and the side wall of the ring is angle two, and the angle one is smaller than the angle two.

[0012] Preferably, the angle one ranges from 58 to 62 degrees, and the angle two ranges from 130 to 140 degrees.

[0013] Preferably, the wind inlet end of the blade surface one is arc-shapedly connected to the wind inlet end of the blade surface three.

[0014] Preferably, the connection between the blade surface one and the ring is connection surface one, and the thickness of the blade surface one gradually decreases from the wind inlet end to the connection surface one.

[0015] Preferably, the thickness of the blade surface two gradually increases first and then decreases from the wind inlet end to the wind outlet end.

[0016] Further, the plurality of blades are radially distributed at variable distances with the hub center as the center in the space between the hub and the ring.

[0017] Preferably, the interval angles of adjacent blades are 46.8-48.6°, 56.2-58.2°, 48-50.5°, 42-44°, 54.8-56.2°, 54.2-55.6°, and 52-54° in sequence.

[0018] The application also provides an axial flow fan to solve the problem of affecting static pressure caused by the pressure difference between the inside and outside of the fan air cavity.

[0019] The axial flow fan comprises a motor, a wind frame and the axial flow blade structure according to any one of claims 1-8, and the wind frame and the hub are connected to the motor; wherein:

[0020] The wind frame comprises a ring-shaped cover ring, which is coaxially covered outside the ring, and a wind gap is left between the cover ring and the ring;

[0021] The ring comprises integrally formed side ring and top ring, and the top ring is folded outward from the top of the side ring to above the cover ring;

[0022] The side ring and the side wall of the cover ring form a side wind gap, and the top ring and the top surface of the cover ring form a top wind gap;

[0023] The cover ring is further provided with a wind guide part below the ring, the inner side wall of the wind guide part protrudes below the side wind gap, and the high-pressure airflow changes direction through the wind guide part and then enters the side wind gap and is discharged through the top wind gap.

[0024] Preferably, the outer diameter of the top ring is greater than or equal to the outer diameter of the cover ring, the side wind gap size is 2-4 mm, the top wind gap size is 2-3.5 mm, the inner diameter of the air guide part is 0-2 mm less than the outer diameter of the side ring, and the top of the air guide part is 1-4 mm away from the bottom of the side ring.

[0025] The beneficial effects of the present application are:

[0026] The special blade shape of the present application deflects from the root to the tip with a gentle trend, so that the inclination angle of surface two is smaller than that of surface one, that is, the wind inlet angle of the blade root is increased, thereby increasing the static pressure, and the wind inlet area of the tip which tends to be gentle takes into account the air volume; and the blade is configured in a segmented structure of surface one, surface two and surface three, surface one is horizontally bent forward from surface three to form a wind breaking area, resisting the vibration of the blade and the blade ring, and effectively reducing the working noise.

[0027] In addition, the asymmetric variable-pitch distribution between the blade rings of the present application improves the resonance frequency band and avoids damage to mechanical parts due to system resonance, and on this basis, the effective thickness of the blade is gradually changed, the thickness of surface one and surface two gradually decreases from the air inlet end, and the thickness of surface three gradually increases first and then decreases from the air inlet end, taking into account the blade strength, wind noise and load energy consumption efficiency.

[0028] The special air guide part, side wind gap and top wind gap structure between the blade ring and the cover ring of the present application, the air inlet direction of the airflow from the low pressure area to the high pressure area, under the action of the pressure difference, backflows along the bent wind gap, which suppresses the backflow and avoids the static pressure drop of the fan; at the same time, the special wind gap size of the present application avoids the "whistling sound" caused by too small wind gap and the mechanical interference between the blade ring and the cover ring after a long time, so the whole has the effect of increasing the pressure and reducing the noise. BRIEF DESCRIPTION OF DRAWINGS

[0029] The accompanying drawings are included to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, to explain the present application, and do not constitute a limitation on the present application. In the drawings:

[0030] Figure 1 is a structural schematic diagram of embodiment 1 of the present application;

[0031] Figure 2 is a top view structural schematic diagram of embodiment 1 of the present application;

[0032] Figure 3 is Figure 2 is a sectional view structural schematic diagram of A-A in FIG. 1;

[0033] Figure 4 is Figure 2 is a sectional view structural schematic diagram of B-B in FIG. 1;

[0034] Figure 5 is a structural schematic diagram of embodiment 2 of the present application;

[0035] Figure 6 and Figure 7 are two cross-sectional schematic diagrams of embodiment 2 of the present application.

[0036] In the figure, the marks are: 1, hub; 2, blade; 21, face one; 22, face two; 23, face three; 24, face one; 25, face two; 26, connecting face one; 3, blade ring; 31, side ring; 32, top ring; 4, wind frame; 41, assembly frame; 42, rib; 43, cover ring; 431, air guide part; 44, side wind gap; 45, top wind gap; 5, wind inlet end. DETAILED DESCRIPTION

[0037] Embodiment 1

[0038] As shown in Figures 1 to 4 , an axial fan blade structure includes a hub 1, a blade 2, and a blade ring 3, the hub 1 and the blade ring 3 are coaxially arranged, and a plurality of blades 2 are installed between the hub 1 and the blade ring 3, and seven blades are taken as an example for illustration in this embodiment. The root and tip of the blade 2 are connected with the hub 1 and the blade ring 3 respectively, and an air guide cavity is formed below the blade to guide the airflow from the top to the obliquely downward.

[0039] Specifically, the following dimensions are taken as an example for illustration in this embodiment: the outer diameter of the hub 1 is 149.5 mm, the outer diameter of the blade 2 is 303.5 mm, and the projection effective length of a single blade in the horizontal plane along the axial direction is 76.75 mm, which is about 46-54% of the size of the hub, preferably 51%.

[0040] The blade 2 includes integrally formed face one 21, face two 22, and face three 23, the face two 22 and the face three 23 are connected with the hub 1 and the blade ring 3 respectively, and the face one 21 is substantially bent into a horizontal plane from the face three 23 to the front (i.e. to the wind inlet side), and considering the convenience of injection molding demolding, the wind inlet end of the face one 21 can be slightly inclined upward by 1-3°. The area proportions of the face one 21, the face two 22, and the face three 23 to the blade are 10-14%, 18-21%, and 65-70% respectively. The airflow enters the face two 22 and the face three 23 at high speed from the wind inlet end of the leading edge of the face one 21, is highly pressurized after passing through the face three 23, and rapidly flies away from the blade at the rear end of the face three 23.

[0041] The wind inlet end of the face one 21 is arc-shapedly transitioned to the wind inlet end of the face three 23, which ensures the overall strength of the blade, and the length of the wind inlet end of the face one 21 accounts for 50-60% of the entire length of the wind inlet end of the blade. The connecting end of the face one and the blade ring is defined as the connecting face one 26.

[0042] Among them, please refer to Figure 3 and Figure 4, the normal projection of the connecting end of the blade 2 on the side wall of the hub 1 forms a face one 24, the normal projection of the connecting end of the blade 2 on the side wall of the hub 1 forms a face two 25, the wind inlet end of the face one 24 and the face two 25 are both inclined upward. The blade 2 deflects from the root to the tip with a gentle trend, so that the inclination angle of the face two 25 is smaller than that of the face one 24, and the normal projection of the face one 24 and the face two 25 on the hub 1 intersects or crosses, that is, the top end of the face two 25 is lower than that of the face one 24, and the bottom end of the face two 25 is not lower than that of the face one 24.

[0043] The twisted shape of the above-mentioned blade 2 can obtain a larger wind inlet angle for the blade face two 22, increase the static pressure, and the gentle wind inlet area of the blade face three 23 can also consider a larger air volume. The horizontal bending structure of the blade face one 21 forms a broken wind area. If the original air fluctuation in the air inlet cavity is not provided, the air fluctuation can stimulate the blade and the blade ring to produce regular vibration. The blade face one breaks the original air inlet cavity and the air vibration propagation path, thereby breaking or resisting the vibration of the blade and the blade ring, and reducing the vibration noise.

[0044] Specifically, please refer to Figure 6 The included angle between the wind inlet end 5 of the blade face two and the side wall of the hub is an angle one a, and the included angle between the wind inlet end 5 of the blade face three 23 and the side wall of the blade ring 3 is an angle two b, and the angle one a is smaller than the angle two b. Preferably, the range of the angle one is 58-62°, and the range of the angle two is 130-140°.

[0045] Please refer to Figure 2 In this embodiment, the distribution structure of the blade 2 is also improved. The seven blades 2 are distributed in the space between the hub 1 and the blade ring 3 in a radial variable-pitch distribution with the hub center as the center. Preferably, the interval angles c1-c7 of adjacent blades are 46.8-48.6°, 56.2-58.2°, 48-50.5°, 42-44°, 54.8-56.2°, 54.2-55.6°, and 52-54°, respectively. More preferably, the interval angles of adjacent blades are 48°, 57°, 49°, 42.7°, 55.3°, 55°, and 53°, respectively. The variable-pitch distribution of the blades improves the resonance frequency band, avoids system resonance and damage to mechanical parts, and also reduces vibration noise.

[0046] In this embodiment, the thickness of the blade 2 is also improved. The thickness of the blade face one 21 gradually decreases from the wind inlet end to the connecting face one 26. The thickness of the blade face two 22 also gradually decreases from the wind inlet end to the wind outlet end. The thickness of the blade face three 23 first gradually increases from the wind inlet end to the wind outlet end, and then gradually decreases.

[0047] For example, in the direction from the air inlet end 5 to the rear, the thickness of the first blade surface 21 gradually changes from 2.2 mm to 1.4 mm, the thickness of the second blade surface gradually changes from 2.2 mm to 1.8 mm, and the thickness of the third blade surface 23 gradually changes from 2.0 mm to 3.2 mm in the middle part and then gradually changes from 3.2 mm in the middle part to 1.8 mm at the rear. Compared with the conventional equal-thickness blade, the thickness of the blade in the embodiment gradually changes, the thickness of the air inlet end 5 and the middle part of the third blade surface is relatively large, the thickness of the blade 2 is increased to improve the strength of the blade 2, and the rear of the blade 2 is gradually thinned to reduce the weight of the blade, the wind noise and the load energy consumption efficiency are reduced under the condition of ensuring the air volume.

[0048] According to the test standard of GB / T1236-2017, the static pressure and air volume test data of the embodiment and the conventional axial flow fan are compared as follows:

[0049]

[0050] From the above data, it can be seen that the greater the standard static pressure of the embodiment is, the more obvious the improvement of the air volume is.

[0051] Embodiment 2

[0052] Please refer to Figures 5 to 7 The application also provides an axial flow fan, which comprises a motor, a wind frame 4 and the axial flow fan blade structure in the embodiment 1, the wind frame 4 is fixedly installed on the motor, and the hub 1 is connected to the output shaft of the motor and is driven to rotate by the motor.

[0053] Please refer to Figure 5 The wind frame 4 comprises an assembly frame 41, a rib 42 and an annular cover ring 43, the assembly frame 41 is installed on the motor, and a plurality of ribs 42 are connected between the assembly frame 41 and the cover ring 43 to ensure the overall mechanical strength of the wind frame.

[0054] The cover ring 43 is coaxially covered outside the blade ring 3, and since the cover ring 43 does not contact the blade ring 3, a wind gap is formed at this position when the fan blade rotates, and the airflow flows from the low-pressure area to the high-pressure area from top to bottom. Due to the action of the pressure difference, part of the airflow in the high-pressure area flows back outward through the wind gap, thereby affecting the static pressure of the fan.

[0055] Please refer to Figure 6 and Figure 7 In order to suppress the static pressure, the blade ring 3 of the embodiment comprises an integral side ring 31 and a top ring 32, and the top ring 32 is folded outward from the top of the side ring 31 to above the cover ring 43. The side wind gap 44 is formed between the side ring 31 and the side wall of the cover ring 43, and the top wind gap 45 is formed between the top ring 32 and the top surface of the cover ring 43. The airflow enters the top wind gap 45 after turning through the side wind gap 44, and the larger wind resistance effectively suppresses the pressure difference backflow.

[0056] The cover ring 43 is further provided with a wind guide part 431 below the vane ring 3. The thickness of the wind guide part 431 is relatively large, and the inner side wall thereof protrudes inwardly below the side wind gap 44. Therefore, the high pressure air flow can only enter the side wind gap 44 after changing an angle through the wind guide part 431, and is discharged by the top wind gap 45, further suppressing the backflow.

[0057] Specifically, the outer diameter of the top ring 32 is slightly larger than or equal to the outer diameter of the cover ring 43, the size of the side wind gap 44 is 2-4 mm, the size of the top wind gap is 2-3.5 mm, the inner diameter of the wind guide part 431 is 0-2 mm smaller than the outer diameter of the side ring 31, and the top of the wind guide part 431 is 1-4 mm away from the bottom of the side ring 31. Through the above specific size configuration, it is ensured that the wind gap is large enough to facilitate assembly, and mechanical interference will not occur after long-term use, and the "whistling sound" in the backflow area is avoided; at the same time, the wind gap is not too large, and the backflow can be effectively suppressed.

[0058] The above only describes the preferred embodiments of the present application and is not used to limit the present application. Although the present application is described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments or equivalently replace some technical features. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An axial fan blade construction comprising a hub, a blade and a shroud, characterised in that: The root and tip of the blade are connected with the hub and the ring respectively, thereby forming a wind guide cavity below the blade; The connection end of the blade with the hub forms a plane one in the orthographic projection of the hub side wall, and the connection end of the blade with the ring forms a plane two in the orthographic projection of the hub side wall, the wind inlet end of the plane one and the plane two are both inclined upward; the blade deflects gently from the root to the tip, so that the inclination angle of the plane two is smaller than that of the plane one; The blade comprises integrally formed blade face one, blade face two and blade face three, the blade face two and the blade face three are connected with the hub and the ring respectively, the angle between the wind inlet end of the blade face two and the side wall of the hub is angle one, the angle between the wind inlet end of the blade face three and the side wall of the ring is angle two, the angle one is smaller than the angle two; the range of the angle one is 58-62°, and the range of the angle two is 130-140°; The wind inlet end of the blade is provided with the blade face one which is horizontally bent forward from the blade face three, forming a broken wind area, and the blade face one is connected with the ring.

2. The axial fan blade structure according to claim 1, characterized by The orthographic projection of the plane one and the plane two intersect with each other, and the top end of the plane two is lower than that of the plane one, and the bottom end of the plane two is not lower than that of the plane one.

3. The axial fan blade structure according to claim 1, characterized by The wind inlet end of the blade face one is arc-shapedly connected with the wind inlet end of the blade face three, and the length of the wind inlet end of the blade face one accounts for 50-60% of the length of the whole wind inlet end of the blade.

4. The axial fan blade construction of claim 1 wherein, The connection between the blade face one and the ring is a connection plane one, and the thickness of the blade face one gradually decreases from the wind inlet end of the blade face one to the connection plane one; the thickness of the blade face three gradually increases first and then gradually decreases from the wind inlet end to the wind outlet end.

5. The axial fan blade construction of claim 1 wherein, A plurality of blades are distributed radially with the hub center as the center in the space between the hub and the ring.

6. The axial fan blade structure according to claim 5, wherein The interval angles of adjacent blades are 46.8-48.6°, 56.2-58.2°, 48-50.5°, 42-44°, 54.8-56.2°, 54.2-55.6°, and 52-54° in sequence.

7. An axial flow fan characterised in that, The axial fan blade structure comprises a motor, a wind frame and the axial fan blade structure according to any one of claims 1-6, the wind frame and the hub are connected with the motor; wherein: The wind frame comprises a ring-shaped cover ring which is coaxially covered outside the ring, and a wind gap is left between the ring and the cover ring; The ring comprises an integrally formed side ring and a top ring, the top ring is folded outward from the top of the side ring to above the cover ring; The side wind gap is formed between the side wall of the cover ring and the side ring, and the top wind gap is formed between the top surface of the cover ring and the top ring; The cover ring is further provided with a wind guide part below the ring, the inner side wall of the wind guide part protrudes below the side wind gap, the high-pressure airflow changes the direction through the wind guide part and then enters the side wind gap and is discharged through the top wind gap.

8. The axial fan of claim 7, wherein, The outer diameter of the top ring is greater than or equal to the outer diameter of the cover ring, the size of the side wind gap is 2-4 mm, the size of the top wind gap is 2-3.5 mm, the inner diameter of the wind guide part is 0-2 mm smaller than the outer diameter of the side ring, and the top of the wind guide part is 1-4 mm away from the bottom of the side ring.

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