JPS63243490A - Electric fan - Google Patents

Abstract

PURPOSE:To promote the thinness of each guard and the reduction of noise, by specifying each crossing angle or the like of each guard piece with respect to suction and delivery side surfaces of a blade in an impeller, in case of the suction and delivery side guards provided before and after the impeller of axial flow type. CONSTITUTION:An electric fan mounts an impeller 2 of axial flow type to an electric motor 1, mounted to a stand 6, while provides suction and delivery side guards 3, 4 respectively so as to cover the impeller 2. And each guard 3, 4 is constituted connecting a circular ring 8 with a mark 9 by many guard pieces 7. Here each guard piece 7 is formed in such a manner that it has crossing angles alpha, beta respectively of 15 deg.-165 deg. in whatever position the guard piece 7 may be placed on a suction or delivery side end surface in a blade 5 of the impeller 2. While the delivery side guard 4 respectively sets its axial direction length l to 5mm or more further ratio of the guard piece 7 to its space to 0.3 or more.

Description

[Detailed description of the invention] Industrial applications The present invention relates to an electric fan.

2. Description of the Related Art Conventionally, this type of electric fan has a large thickness in the axial direction, and there has been a demand for a thinner product. Therefore, in the conventional electric fan, as shown in FIGS. 9 and 10, an electric motor 1, an impeller 2 driven by the electric motor 1, a suction side guard 3 attached to the electric motor 1, and the suction side guard 3 The aim was to make the discharge side guard 4 attached to each one thinner, thereby reducing the thickness of the product.

Problems to be Solved by the Invention In the above-mentioned conventional electric fan, noise is increased because the gaps between the impeller 2 and the suction side guard 3 and the discharge side guard 4 are small. In addition, in order to suppress noise as much as possible, the impeller 2
Since the installation angle of the blades 6 is large and the operation is performed at low rotation speed, there is a problem that the discharge flow has a large rotational turn in the rotational direction, the wind speed on the discharge side is poor, and the distance traveled by the discharge flow is shortened.

The present invention has been made in consideration of the above-mentioned conventional problems, and an object of the present invention is to provide an electric fan that reduces noise and has a high wind speed.

Means for solving the problem In order to solve this problem, the present invention installs a suction side guard and a discharge side guard at the front and rear of an axial flow type impeller.
The suction side guard has an intersecting angle of 16° to 166° with the suction side end face of the blade of the impeller, and the discharge side guard has an intersection angle of 16° to 166° with the suction side end face of the blade of the impeller.
The radial guard has a crossing angle of 65°, and the axial width of the discharge side guard is 511111 or more, and the total ratio to the guard interval is 0.3 or more.

Effect: With this configuration, the air sucked from the suction side is sucked with the sound phase shifted between the blade and the suction side guard, and the air discharged from the impeller is sucked with the sound phase shifted and the sound phase shifted between the blade and the suction side guard. The air is discharged while being guided toward the center by the discharge side guard, reducing noise and increasing wind speed.

EXAMPLE Hereinafter, an example of the present invention will be explained based on FIGS. 1 to 8. Note that the same numbers are given to the same parts as in the conventional example, and detailed explanations are omitted. In the figure, reference numeral 1 denotes an electric motor mounted on a stand 6, on which a trickle-type impeller 2 is fixed. A locking side guard 3 is attached to the electric motor 1 so as to cover the impeller 2. The above-mentioned suction side guard 3 includes
A discharge side guard 4 is attached to cover the impeller 2. In addition, as shown in FIG. 8, the impeller 2 normally has a blade 5 attached to the blade boss 1o at an installation angle θ, and sucks air from the suction side end face ab and from the discharge side end face cd↓. Exhale air. As shown in FIG. 1, the suction side guard 3 and the discharge side guard 4 are constructed by connecting a ring 8 and a mark 9 with a large number of guard pieces 7. The guard piece 7 of No. 3 has an angle of 15° to 1° at any position on the suction side end face ab of the blade 6.
The guard piece 7 of the discharge side guard 4 also has a cross angle β of 16° to 166° at any position on the discharge side end face ad of the blade 6. It is configured.

In the above configuration, when the impeller 2 is rotated by the electric motor 1, the air sucked through the suction side guard 3 is moved between the suction side end surface of the blade 6 of the impeller 2 and the suction side guard [
a and generates a sound with a specific frequency, which is usually called rotational sound, but since the intersection angle α between the suction side guard 3 and the end face of the blade 5 is 15° to 165°, there is a time delay in the rotational sound. occurs and is reduced. In addition, the discharge flow after passing through the impeller is compressed by the gap between the discharge side end face of the blade 6 and the discharge side guard, and similarly rotation noise is generated, or the discharge flow between the discharge side guard 4 and the blade 6 is compressed. Since the intersection angle β with the discharge side end face is also 15' to 1650, rotation noise is reduced. In general, the discharge flow of an axial flow impeller usually has a nodal component, but if the impeller is thin in the axial direction, it will generate a lot of noise, so it is recommended to increase the mounting angle and reduce the rotation. Noise is reduced. In this case, the nodal component of the discharge flow is large, and the flow after exiting the discharge 21I flow is scattered left and right, but the discharge side guard 4 is axially
Since it has the above length l and the ratio of the guard piece 7 to the interval t is 0.3 or more, the discharge flow collides with the guard piece 7 and is guided in the axial direction. Further, since the discharge side guard is not simply radial but twisted in the opposite direction to the rotational direction, the discharge flow that hits the guard piece 7 is also guided toward the center with a centerward component cf. As a result, the wind speed distribution measured at a position three times the blade diameter (JIS measurement) on the discharge side of the electric fan has a wind speed type as shown in FIG.

Effects of the Invention As is clear from the description of the embodiments above, according to the present invention, even if the guard is thinned and the gap between the impeller and the guard approaches, the noise does not increase and the wind speed at the outlet increases. , the effect of a wind speed with a long reach can be obtained.

[Brief explanation of drawings]

Fig. 1 is a front view of the discharge side of an electric fan according to an embodiment of the present invention, Fig. 2 is a front view of the suction side of the electric fan, Fig. 3 is a side view of the electric fan, and Fig. 4 is a guard on the discharge side of the electric fan. Figure 6 is a wind speed distribution diagram showing a comparison between the present invention and the conventional example, Figure 6 is a characteristic diagram showing the relationship between the guard interval and maximum wind speed of the discharge side guard, and Figure 7 is the intersection angle. FIG. 8 is a side view of the impeller of the electric fan, FIG. 9 is a front view of the conventional electric fan, and FIG. 10 is a side view of the electric fan. 2... Impeller, 3... Suction side guard,
4...-Discharge side guard, 6...Blade. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 3
Figure 4 Figure 5 Figure 6 t Figure 7 Sarakan ll4m, β

Claims (1)

[Claims] A suction side guard and a discharge side guard are attached to the front and rear of the axial flow type impeller, and the suction side guard is a radial guard having an intersecting angle of 15° to 165° with the suction side end face of the blade of the impeller, The discharge side guard is a radial guard with an intersecting angle of 15° to 165° with the discharge side end face of the blade of the impeller, and the axial width of the discharge side guard is 5 mm or more, and the guard spacing is ratio to 0
．． A fan with a rating of 3 or higher.