KR920004970Y1 - Impeller for multiblade blower - Google Patents

Abstract

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Description

Impeller of Multiblade Blower

Figure 1a is a partially notched perspective view of a typical crossflow blower.

1b Turning round main part cross section.

2A and 2B are analysis diagrams of noise frequencies of a blower using different conventional configurations, respectively.

3 is a perspective view in which part of the impeller is notched in different conventional examples.

Figure 4 is a perspective view of the blade portion of the impeller of the cross flow in one embodiment of the present invention.

Sections 5a, 5b or cross sectional blowers with said blades respectively.

6 is an explanatory diagram showing a state of air flow by the blade.

7 is a diagram illustrating the noise frequency of a blower equipped with the same cross flow impeller.

8A, 8B are a perspective view of a centrifugal impeller according to another embodiment of the present invention, and a cross-sectional view of a blower having an impeller.

9 is a perspective view of the blade portion of the impeller according to another embodiment of the present invention.

10 is an explanatory diagram showing a state of air flow by the same blade.

11 is a characteristic view of the blower provided with the said impeller and the blower of a prior art example.

* Explanation of symbols for main parts of the drawings

1: impeller 2: ballast

3: rear guider 4: partition

5 blade 6,7 circumference

The present invention relates to a multiblade impeller such as a cross flow fan or a sirocco fan widely used as a blower such as an air conditioner.

As an example of a multiblade blower, a general crossflow blower was the same as that disclosed in JP-A-60-17296 or JP-A-59-167990.

That is, as shown by the arrow of FIG. 1A, the cross flow blower has a structure in which the inflow direction and the outflow direction of the air are opposite to each other, and when the blower is extended in the axial direction, the air volume increases approximately in proportion to its length. In recent years, it has become widely available because it has features that are not seen.

As shown in Fig. 1a, the pitch angle between the blades a of the impeller does not have periodicity, and the rotation noise (nz noise, n: rotational speed, z: number of blades) that can be felt by arranging randomly is felt to be reduced. The technique to do is also known.

The general nz frequency analysis characteristics are shown in FIG. 2a, and the nz frequency analysis characteristics are shown in FIG.

Another example is the configuration of a centrifugal blower as disclosed in Japanese Unexamined Patent Publication No. 60-12959.

The centrifugal blower shown in FIG. 3 has a structure in which fluid flows from the radial or otherwise oblique direction at the fan inlet b and widens in the radial direction at the outlet a and flows out.

The above structure is often used in a place with high load due to high static pressure, and the blade (d) is formed into an airfoil shape to improve air force characteristics and air volume characteristics.

However, with respect to the crossflow blower shown in FIG. 1, the pitch angles of the blades are irregularly arranged as described above, and as shown in FIG. Although the flute sound is alleviated, n sounds (n: revolutions) per cycle are remarkable, and the hearing can be actually reduced.

In addition, the pitch angle between the blades is irregular, there is also a problem that the air volume is lowered.

In the centrifugal blower shown in FIG. 3, the blade is used as an airfoil to improve efficiency. However, the thickness of the blade increases, so that the weight becomes heavy. For example, even with a hollow structure, the number of parts increases and the cost increases. Will rise.

The present invention aims to provide a low cost, light weight multiblade blower designed to reduce and reduce fan noise and improve air volume characteristics thereon in view of the above problems.

In order to solve the above problems, the multi-blade blower of the present invention extends in the longitudinal direction to the blade tip of the impeller outer circumference and provides a circumferential portion having a diameter larger than the thickness of the blade tip.

According to the above configuration, the air that crosses the blades is relaxed by the circumference of the air generated when it crosses, and as a result, it is possible to mitigate wind noise or n sound, and furthermore, the trailing flow swirl vortex).

Next, some embodiments of the present invention will be described with reference to the accompanying drawings.

First, the case of employing the crossflow fan according to FIGS. 4 to 6 will be described.

Since the basic structure of the blower employing the crossflow fan is the same as that of FIG. 1a, the basic structure will be described using FIG. 1a.

In the figure, (1) is a crossflow fan (hereinafter referred to as an impeller) (2) is a ballast, (3) a rear guider, (4) a partition arranged at a predetermined interval, (5) a partition (4) It is a blade disposed between. According to these, the blower is comprised.

4, the circumferential part 6 is provided in the outer peripheral side front end of the blade 5 in the longitudinal direction of the blade 5, and is provided.

The diameter T of this circumferential part 6 is set larger than the thickness t of the tip of the blade 5, as shown in FIG.

In the blower having the above-described configuration, when the arrangement pitches of the blades 5 are not equally spaced, the fifth pitch is the same. When the pitches of the blades 5 are equally spaced, the fifth pitch is the same. do.

Next, the flow of air across the blade 5 will be described with reference to FIG.

Arrows in this figure indicate the direction of wind flow.

Generally, separation by the turbulent boundary layer near the trailing edge of the blade 5, trailing edge swirl at the exit of the blade, lift force fluctuation of the blade surface, pressure fluctuation, and the like can be cited as the causes of the noise.

However, by providing the circumferential portion 6 at the blade tip portion on the outer peripheral side of the fan, even if the sound is generated by being blocked at the deposit tip portion of the wing on the conventional suction side, the sound can be smoothly traversed without being distracted by the flow of the wind. Can be.

In addition, when the dead water region hangs over the wind due to the fluctuation of the downstream flow width, the wind speed can be reduced to prevent the loss.

In such a case, the generation of the trailing stream vortex is also irregular, the size of the vortex is also dispersed, and the generation of sound due to the vortex can be reduced.

7 shows frequency analysis when the present invention is implemented in a crossflow fan arranged at a blade random.

As apparent from the drawing, the present invention has n sounds compared to the conventional random fan, so that the noise in the low frequency region can be reduced as shown in the following table (1).

As a result, it was very good that the sound that actually heard and disappeared was lost. Moreover, such results were obtained according to the following experiment.

[Fan size]

Fan diameter: 86mm

Number of wings: 36

Inside and outside diameter ratio: about 0.79

Blade Thickness: 4.4mm

Now of the circumferential part 6: about 1mm

Number of trainings: 8

TABLE 1

In addition, according to the present invention, similar results can be obtained when the blades 5 are arranged at the same pitch as shown in FIG. 5B.

Furthermore, the present invention can be similarly implemented for the centrifugal blower as shown in FIG.

That is, such an impeller has a characteristic that air flows in from the axial direction, otherwise the oblique direction, expands in the radial direction and flows out as shown by the arrow of this drawing, and the outer diameter side of the impeller in the blade 5 The circumference is provided at the tip.

Also in such a structure, the favorable result of the same tendency as 7th grade was obtained.

In the eighth aspect, (1) is an impeller, (2a) is a spiral casing, (3a) is a boss, (4) is a partition, (5) is a blade, and (6) is a circumference.

As described above, according to the present embodiment, the blade 5 is formed by providing the circumferential portion 6 having a diameter T larger than the thickness t of the tip of the blade 5 at the fan outer peripheral side end of the blade 5. Separation of the air generated when the air at the exit side of the gas traverses can be suppressed, and noise resulting from this can be reduced.

In particular, audible dominant sounds such as n sounds and nz sounds can be alleviated.

Next, another embodiment of the present invention will be described with reference to FIGS. 9 to 11.

In these figures, (4) is a partition, (5) is a blade, (6) is a circumference part provided in the fan outer peripheral side front end in the blade 5, (7) is a fan inner peripheral side in the blade 5 It means the circumference part provided in the front-end | tip, and each circumference | surroundings 6 and 7 are formed with diameter larger than the thickness of the blade 5 front-end | tip.

These circumferential portions 6 and 7 extend in the longitudinal direction of the blade 5 in the same manner as in the first embodiment.

The flow of air across the blade 5 in the multiblade blower constructed as described above will be described with reference to FIG.

When the blades cross the flow of air with respect to the conventional suction flow, a sharp wind-wind noise (air noise) is generated, or the airflow characteristics are significantly reduced by the collision loss at the inflow. come.

Thus, since the circumferential portion 7 is also provided on the inner circumferential side of the blade 5 in addition to the above embodiment, separation of air is unlikely to occur even if the direction of the suction flow and the wing entrance angle are slightly shifted.

Therefore, the fall of the blowing efficiency and noise generation by air separation become small. 11 is a graph comparing the air volume characteristics of the present invention with the conventional structure in the crossflow blower.

In the drawing, (e) is a fan with an irregular pitch angle of a conventional blade, (d) is a fan with a same pitch angle with a copper blade, and (f) is a fan of the present invention. It is the structure which provided the circumference part 6,7.

From the above drawings, the amount of air tends to decrease as the number of rotations increases as compared to fans having the same pitch angle.

However, in the constitution of the present invention, by providing the circumferential portions 6 and 7 on the inner and outer circumferences of the random fan, the air flow characteristics of the same pitch can be obtained, and the blowing performance can be improved.

The experimental content and result of such a structure are shown next.

[Fan size]

Package diameter: 86mm

Number of wings: 36

Inside and outside diameter ratio: about 0.79

Blade Thickness: 0.5mm

Diameter of the circumferential part 6: about 1mm

Diameter of the circumferential portion 7: about 1mm

Number of trainings: 8

TABLE 2

As described above, the circumferential portions 6 and 7 having a diameter larger than the thickness of the tip of the blade 5 are provided at both ends of the blade in the longitudinal direction of the blade 5, thereby simultaneously reducing noise and airflow characteristics. can do.

In addition, the blade shape of the blade is also lightweight and can be molded in a relatively low cost.

It is apparent that such a configuration can be similarly applied to the centrifugal impeller as shown in FIG.

Furthermore, in each of the above embodiments, the transverse flow pen has been described in the case of a so-called plurality of configurations in which end plates and partitions 4 are arranged at regular intervals in the axial direction. It goes without saying that the same effect can be obtained also in the case of annealing.

As is apparent from the above-described embodiment, the present invention is an impeller of a multi-blade blower, which extends over the entire length of the blade in the blade tip on the outer peripheral side of the impeller, and also has a circumference having a diameter larger than the thickness of the blade tip. With the provision, it is possible to suppress the unique n sound and nz sound of the impeller, and to achieve a silent sound.

In addition to the above-described configuration, by installing the same circumferential portion at the blade tip of the impeller inner circumferential side, the noise characteristic and the air volume characteristic can be improved at the same time.

Claims (2)

In the impeller (1) in which a circular end pate or partition (4) disposed at regular intervals and a plurality of blades (5) arranged at the peripheral edge of the end plate or partition between the end plates or partitions, At the tip of the blade 5 of the outer circumference, the circumferential portion 6 is provided to extend over the entire length of the blade, and the diameter of the circumferential portion is larger than the thickness of the portion connecting the circumferential portion in the blade 5. Impeller of the multi-blade blower characterized in that. The impeller 1 is provided with a circumferential portion 7 at the tip of the blade 5 on the inner side of the impeller over the entire length of the blade, and the diameter of the circumferential portion is equal to that of the circumferential portion on the blade. The impeller of the multi-blade blower characterized by being larger than the thickness of the part to connect.