Improved axial fan blades can effectively overcome the shortcomings of the prior art, are easy to stack, prevent collisions, and achieve the purpose of convenient packaging, transportation and storage. The fan blades include a hub, blades and a middle plate located in the hub.

 

One end of the hub is the front mold hub end, and the other end is the rear mold hub end. The front and rear mold hub ends are both cylindrical. It is characterized in that the inner cavity of the front mold hub end of the hub is inverted “convex”, the rear mold of the hub The end of the hub is similar to the shape of "convex". The end of the hub is formed on the boss and the outer ring platform. At the axial end of the boss, there are a plurality of grooves evenly distributed along the circumference.

 

The axial length of the groove is greater than the length of the axial protrusion. The inner cavity at the end of the hub has an inner ring platform, which has an arc-shaped tongue along the surface of the inner cavity, and the end of the rear mold hub is inserted into the front mold. The hub end of the cavity is supported by the inner ring platform, and the front mold hub end is supported by the outer ring platform.

 

When the axial flow fan blades are stacked, two adjacent axial flow fan blades and one axial flow fan blade are located behind the hub, the hub end of the mold is inserted into the inner cavity of the hub end of the front mold, and the hub end of the rear mold is inserted into the inner front The cavity at the end of the mold hub supports the inner ring platform.

 

When the fan blades are separated at equal angles, a series of harmonic resonances will appear, and the frequency of the series of harmonics corresponds to an integer multiple of the blade passing frequency, which corresponds to the product of the number of fan revolutions per second and the number of blades. The resonance phenomenon generates noise, which may interfere with human hearing.

 

Although the discomfort caused by noise is mainly subjective, there are two factors that affect the interference of the sound: the sound pressure level (that is, the intensity of the noise) and the pitch distribution of the noise. Therefore, if the pitch distribution of the noise distinguishes it from the background noise On, even low-intensity noise may be annoying.

 

Provide a method for calculating the angular spacing between axial flow fan blades, which is converted into an improved fan type implementation method in terms of noise, especially in the sense of noise, so that the generated noise becomes may.

 

By calculating the integral of the sound intensity values ​​at different frequencies (total noise), the noise generated in the case of blades with unequal angles is approximately equal to the noise generated in the case of blades with equal angular intervals. However, the different pitch distribution of the noise makes Sound comfort is higher.