Fan blade of electric fan

Abstract

The electric fan blade comprises a rotatable hub and a plurality of blades arranged on the periphery of the hub, a shaft hole is formed in the hub, the blades are obliquely arranged on the periphery of the hub in the direction opposite to the rotating direction of the hub from the air inlet direction to the air outlet direction, a plurality of sawtooth-shaped air cutting openings are formed in the tail ends of the blades in the air inlet direction, and the blades are arranged in the shaft hole. Turbulent flow in airflow can be effectively broken, and noise caused by irregular airflow movement is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric fan, in particular to the technical field of electric fan blade. BACKGROUND

[0002] Electric fan is a relatively mature and popular household appliance. Therefore, at present, the development of electric fan, more specifically the development and design of fan blade, is mainly focused on how to balance the relationship among air volume, air speed and noise.

[0003] Especially the noise, which is inversely proportional to air volume and air speed, so theoretically, as long as the noise is reduced, at least the air volume and air speed can be improved under the same noise level. For this purpose, the patent CN114294086A discloses a cooling fan with a blade tip sawtooth structure and a method for calculating the aerodynamic noise of the cooling fan, which designs a sawtooth structure on the blade tip of the fan blade to reduce noise.

[0004] However, the market test of electric fan is the overall experience, which requires low noise, considers coolness, that is, sufficient air volume, and also considers the air outlet distance. In addition to increasing air speed, the air outlet distance can also be increased by wind aggregation. SUMMARY

[0005] In view of the above-mentioned needs, the present application proposes an electric fan blade, which optimizes the structural design of the fan blade to achieve the best balance among air volume, air speed, energy efficiency and noise.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0007] The present application proposes an electric fan blade, which comprises a rotatable hub, a plurality of blades arranged on the outer periphery of the hub, and a shaft hole provided in the hub.

[0008] The blades are arranged obliquely on the outer periphery of the hub against the rotation direction of the hub from the air inlet direction to the air outlet direction, and the air inlet end of the blade is provided with a plurality of sawtooth-shaped air cutting ports.

[0009] In this way, the sawtooth-shaped air cutting port arranged at the air inlet end of the blade can effectively break the turbulence in the airflow and reduce the noise caused by irregular airflow movement. This helps the air to pass through the blade more smoothly, and the obliquely arranged blade design can more effectively capture and accelerate the airflow, thereby providing greater air volume and higher air speed.

[0010] In some possible embodiments, the number of blades is 5.

[0011] In some possible embodiments, the blade is provided with a negative curvature concave portion recessed towards the air inlet direction.

[0012] In some possible implementation manners, the curvature of the inner recess gradually decreases towards the blade tip.

[0013] In some possible implementation manners, the number of the air cutting openings is at least 3, and the sawtooth depth gradually decreases towards the hub.

[0014] In some possible implementation manners, the number of the air cutting openings is 4.

[0015] In some possible implementation manners, the blade coverage angle of the blade on the hub is more than 70% of the static inter-blade angle.

[0016] In some possible implementation manners, the inner side of the hub is provided with a shaft column, the shaft hole is arranged in the shaft column, and a plurality of reinforcing ribs are arranged between the shaft column and the hub. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 is a schematic view of the overall rear view of the fan blade of the electric fan according to the present application;

[0018] Figure 2 is a schematic view of the side view of the fan blade of the electric fan according to the present application;

[0019] Figure 3 is a schematic view of the sectional view of the blade of the fan blade of the electric fan according to the present application;

[0020] Figure 4 is a schematic view of the rear view projection of the fan blade of the electric fan according to the present application;

[0021] Figure 5 is Figure 4 is a schematic view of the enlarged view of the part D in FIG. 8. DETAILED DESCRIPTION

[0022] The features of the present application and other related features are further described in detail by the following examples, so as to facilitate the understanding of the skilled in the art:

[0023] It should be noted that the words "front", "rear", "left", "right", "upper" and "lower" used in the following description refer to the directions in the drawings, and the words "bottom surface" and "top surface", "inner" and "outer" refer to the directions towards or away from the geometric center of the specific component.

[0024] Further, unless otherwise clearly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be directly connected, or indirectly connected through an intermediate medium; can be the communication inside two elements. For those skilled in the art, the specific meaning of the above terms in the present case can be understood according to the specific circumstances.

[0025] Please refer to Figure 1 and Figure 2 , the applied scenario of the electric fan blade of the present application is mainly low-frequency noise, that is, the fan speed is generally in the range of 1100-1800r / min. This noise is mainly caused by the cutting of air by the blade and the turbulence formed after the airflow passes through the blade.

[0026] To this end, the electric fan blade of the present application comprises a rotatable hub 1, the hub 1 is provided with a shaft hole 11, and a plurality of blades 2 are arranged on the outer periphery of the hub 1. In the preferred embodiment, the number of blades 2 is 5. Specifically, a shaft column 12 is arranged on the inner side of the hub 1, and at this time the shaft hole 11 is arranged in the shaft column 12. At the same time, a plurality of reinforcing ribs 13 are arranged between the shaft column 12 and the hub 1, which can control the contact area of the hub 1 and the blade 2 in the design end.

[0027] Firstly, in the contact between the blade 2 and the hub 1, the connection line 21 presents an oblique line. Specifically, the blade 2 is arranged obliquely on the outer periphery of the hub 1 from the air inlet to the air outlet against the rotation direction of the hub 1, and the connection line 21 formed thereby is an oblique line. The obliquely arranged blade 2 design can more effectively capture and accelerate air flow, thereby providing greater air volume and higher air speed.

[0028] Further, a plurality of sawtooth-shaped air cutting openings 22 are arranged at the end of the air inlet direction of the blade 2. In some embodiments, the number of air cutting openings 22 is at least 3, and the sawtooth depth X1 gradually decreases towards the hub 1, which can better control the separation point of the airflow and avoid noise caused by sudden pressure changes. Preferably, the number of air cutting openings 22 is 4.

[0029] In this way, the sawtooth-shaped air cutting openings arranged at the end of the air inlet direction of the blade 2 can effectively break the turbulence in the airflow, reduce the noise caused by irregular airflow movement, and help the air to pass through the blade more smoothly. Specifically, when the fan blade 2 rotates at high speed, the end of the blade 2 is the area with the fastest speed, which is prone to strong turbulence. These turbulent flows will cause irregular airflow movement, thereby causing noise. The sawtooth design can effectively disperse the airflow, making the airflow pass through the edge of the blade 2 more smoothly and reducing the formation of turbulence.

[0030] The balance design of air volume and air speed is described as follows in combination with the blade 2 and the connection design of the blade 2 with the hub 1.

[0031] Please refer to Figure 2 and Figure 3 , the blade 2 is provided with a concave portion 23 with negative curvature recessed towards the air inlet direction. Specifically, this concave portion 23 is recessed towards the air inlet direction, so from the air inlet end the blade 2 is the part bulging out of the concave portion 23, and from the air outlet end it is recessed.

[0032] Therefore, this area can effectively gather air, and when the fan blades rotate, it can blow out a larger amount of air from the front, improving the blowing performance and energy efficiency of the fan blades. Figure 3 The application continuously refers to the cross-sectional effects of A-A, B-B, and C-C, which are the cross-sectional effects of the numbered blades Y1 alone. That is, the absolute value of the curvature of the inner recess 23 gradually decreases towards the end of the blade 2, and the inner recess 23 is deeper near the hub 1. The air gathering effect is better, and the amount of air in the middle is more. At the same rotation speed, the increase in local air volume will lead to an increase in local wind speed, which will improve the air supply distance.

[0033] Further, please refer to Figure 4 As mentioned above, the blades 2 are obliquely arranged on the outer periphery of the hub 1, and the blade coverage angle Z1 accounts for more than 70% of the static blade angle Z2. That is, when there are 5 blades 2, the static blade angle Z2 is 72°, and at this time, the blade coverage angle Z1 is at least 50.4°. In this way, each blade 2 can cover more circumferential space. This means that when the fan rotates, each blade 2 can more effectively push the air, thereby increasing the air flow per unit time. A larger blade 2 coverage angle directly translates into higher air intake and exhaust efficiency, resulting in a significant increase in overall air volume.

[0034] As mentioned above, the present application protects a fan blade for an electric fan, and all technical solutions that are the same or similar to the present application should be considered to fall within the scope of protection of the present application.

Claims

1. A fan blade for an electric fan, characterized in that, It includes a rotatable hub (1) and a plurality of blades (2) disposed on the outer periphery of the hub (1), the hub (1) being provided with a shaft hole (11); The blade (2) is obliquely arranged on the outer periphery of the hub (1) from the air inlet direction to the air outlet direction, in the opposite direction of the hub (1) rotation. The air inlet end of the blade (2) is provided with multiple serrated air cut-outs (22).

2. The fan blade as described in claim 1, characterized in that, The number of blades (2) is 5.

3. The fan blade as described in claim 1, characterized in that, The blade (2) is provided with a negative curvature concave portion (23) that is recessed towards the air intake direction.

4. The fan blade as described in claim 3, characterized in that, The absolute value of the curvature of the concave portion (23) gradually decreases toward the end of the blade (2).

5. The fan blade as described in claim 1, characterized in that, The number of air cuts (22) is at least 3, and the serration depth (X1) gradually decreases towards the hub (1).

6. The fan blade as described in claim 5, characterized in that, The number of air cutters (22) is 4.

7. A fan blade as described in claim 1, characterized in that, The blade (2) has a blade coverage angle (Z1) on the hub (1) that accounts for more than 70% of the static inter-blade angle (Z2).

8. The fan blade as described in claim 1, characterized in that, The hub (1) has a shaft post (12) inside, the shaft hole (11) is located inside the shaft post (12), and a plurality of reinforcing ribs (13) are provided between the shaft post (12) and the hub (1).

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