JPH01280700A - Electric blower - Google Patents

Abstract

PURPOSE:To obtain an electric blower of low noise and high output by providing such constitution that the smallest clearance between a fan casing for passing exhaust air and the guide blade of a diffuser is set so as to provide a specific ratio with respect to the inside diameter of the fan casing. CONSTITUTION:Air sucked from the suction port 8 of a fan casing 7 is discharged from the vent hole part of a motor flame 2 through the passage of the spiral guide blade of diffuser 4. When a clearance 11 between the guide of the diffuser 4 and the fan casing 7 is wide, uneven density of air is generated inside the passage so as to generate turbulence. On the other hand, when the clearance 11 is narrow, the vent passage is so narrow that turbulence is generated. When the turbulence is minimum, the noise is lowest, while air output is maximized. By setting the clearance 11 in a ratio of 0.016 to 0.02 with respect to the inside diameter 12 of the fan casing 7, it is possible to obtain an electrically driven blower having low noise and high air output.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an electric blower used in a vacuum cleaner or the like.

BACKGROUND OF THE INVENTION Conventional electric blowers of this type include a fan and a diffuser provided in a casing, and a motor rotates the fan at high speed to obtain air volume and vacuum pressure.

Hereinafter, a conventional electric blower as described above will be described without reference to the drawings.

FIG. 4 is a side view of a conventional electric blower, and the upper half is a cross-sectional view. In FIG. 4, a cylindrical motor frame 1 and a disc-shaped motor frame 2 are fixed by caulking with beam heads 3.

In order to smooth the flow of air, motor frame 2 is equipped with
A diffuser 4 made of resin molding is attached.

A fan 6 is attached to the rotating shaft 5 and covered with a fan casing 7. The fan casing 7 is provided with a suction port 8, and the motor frame 2 is provided with a ventilation hole 9.

The operation of the electric blower configured as above will be described below.

As the rotating shaft 5 rotates, the fan 6 rotates and sucks air through the suction port 8 of the fan casing 7.

Air passes through the inside of the fan 6, passes through the diffuser 4, passes through the ventilation holes 9 of the disc-shaped motor frame 2, and is discharged from the ventilation holes of the cylindrical motor frame 1. This is how air moves.

The diffuser 4 has a large number of spiral guide vanes, and the cross-sectional area of the passage is larger than the outlet area of the fan 6.

Moreover, FIG. 5 is a characteristic curve diagram of vacuum pressure and air output of a conventional electric blower. In FIG. 5, the characteristic curve of the air output draws a parabola with respect to the air volume, and there is a point where the maximum value occurs. The vacuum pressure reaches its maximum value when the air volume is zero.

Problems to be Solved by the Invention However, with the above configuration, when the air coming out of the fan passes through the diffuser 4 and is refracted toward the motor frame 2, the air density in the fan casing 7 increases, causing the passage to become denser and denser. turbulent flow occurs. This causes noise, energy loss, and a reduction in air output.

In view of the above drawbacks, the present invention provides an electric blower with low noise and high air output by improving the shape of the diffuser.

Means for Solving the Problems To achieve this object, the electric blower of the present invention has a minimum clearance between the fan casing and the knife user's guide vane, which is the ratio of the outer circumference of the fan casing to the inner diameter of 0.
016 to 0.02.

Function: With the above-described configuration, when the air coming out of the fan passes between the fan casing and the diffuser, hits the side of the fan casing, and is refracted toward the motor frame, the air density is compressed to approximately double. By reducing the cross-sectional area of the bending portion, air turbulence can be prevented.

Therefore, the air flow becomes smooth, noise is reduced, and a large air output can be obtained.

EXAMPLE Hereinafter, an electric blower according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows the configuration of an electric blower in one embodiment of the present invention. FIG. 2 shows the diffuser fixed to the motor frame. Here, 2 is a cylindrical motor frame, 9 is a ventilation hole portion of the motor frame 2, 4 is a diffuser 110, which is a spiral guide blade provided on the surface of the diffuser 4 on the motor frame side, and 6
is a fan, and 7 is a fan casing. The operation is the same as that of a conventional electric blower, in which air is sucked in from the suction port 8 of the fan casing 7, passes through the inside of the fan 6, passes between the fan casing 7 and the diffuser 4, and is then sent to the side of the fan casing to drive the motor. It is bent toward the frame, passes through the path of the spiral guide blade 10 of the diffuser 4, and is discharged from the ventilation hole 9 of the motor frame 2.

Here, if the gap 11 between the guide vane 10 of the diffuser 4 and the fan casing 7 is large, the passage will be densely spaced and turbulent flow will occur. Further, when the gap 11 is small, turbulent flow occurs because the ventilation path is narrow. When turbulence is at its lowest, noise is at its lowest and at the same time air output is at its highest. By setting the ratio of the gap 11 to the inner diameter 12 of the fan casing 7 to be 0.016 to 0.02, an electric blower with low noise and high air output can be obtained. FIG. 3 is a characteristic correlation diagram showing changes in noise and maximum air output when the gap 11 is changed.

Effects of the Invention As described above, the present invention achieves low noise by setting the ratio of the gap between the guide vanes of the diffuser and the fan casing to the inner diameter of the outer periphery of the fan casing to be O, 16 to 0.02. , a high-output electric blower can be obtained.This is because when a conventional electric blower is used for a vacuum cleaner,
It was necessary to attach a sound-deadening material around the motor, but when using the electric blower of the present invention, it is possible to reduce the size and cost of the equipment without having to attach a sound-deadening material.
Great practical effects can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a partially sectional side view of an electric blower according to an embodiment of the present invention, and Fig. 2 is a partially sectional plan view of the electric blower of the present invention with a diffuser fixed to the motor frame. , Fig. 3 is a characteristic correlation diagram of noise and maximum air output with respect to the gap between the fan casing and the diffuser guide vane, Fig. 4 is a partially sectional side view of a conventional electric blower, and Fig. 5 is a diagram of the characteristics of the electric blower. It is a characteristic curve diagram. 1... Cylindrical motor frame, 2... Disc-shaped motor frame, 3... Rivet, 4...
... Diffuser 15 ... Rotating shaft, 6.
...Fan, 7...Fan casing,
8... Suction port, 9... Ventilation hole, 10
...Guide vane, 11...Gap, 12.
...Fan casing inner diameter. Name of agent Patent attorney Toshio Nakao 1 person Figure 2 Figure 3 0.012 0.0+6 0.02 0.024q″B
Hikyo Figure 4 Figure 5 Air volume [m3/m1n]

Claims (1)

[Claims] A motor frame, a fan fixed to the end of the rotating shaft of the motor, a fan casing fixed to the motor frame, and a large number of spirals fixed between the motor frame and the fan, on the surface on the motor frame side. a diffuser having a shaped guide vane, and the minimum gap between the fan casing and the guide vane of the diffuser through which the exhaust air flow discharged from the fan passes is 0.016 in ratio to the inner diameter of the outer periphery of the fan casing. An electric blower characterized in that the air pressure is set to 0.02.