JPS61294198A - Motor-driven blower - Google Patents

Abstract

PURPOSE:To efficiently reduce the noise generated in an impeller, by forming a rib in the diffuser of an air guide so as to form between the diffuser and a casing, a space which makes a face of contact between the rib and the air flow to be wide, so as to shape a resonant-type silencer from said space. CONSTITUTION:An intake port 22 is formed at the center of a casing 21, and a part of this casing 21 opposite to said intake port 22, is attached to a motor frame 23. Plural diffusers 26 are formed on the outer circumference of an impeller 24 which has plural blades, and return passages 28 which are connected to these diffusers 26 and lead air flow to an intake port 27 of the motor, are formed, and these diffusers 26 and return passages 28 constitute an air guide 25. In this case, a ring rib 29 is formed at the upper part of each of the diffusers 26, so as to form a space 30 between the diffuser 26 and a casing 21. Then, this space 30 is connected to each of the diffusers 26 through the connecting part 31 formed in the rib 29. In this way, a resonant-type silencer is formed from the space 30, and thus, the noise generated in the impeller 24 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electric blower for use in a vacuum cleaner.

Conventional technology Conventional electric blowers of this type are, for example, 52-49168.

That is, as shown in FIG. 7, an impeller 2 and an air guide 3 are provided in a casing 1, and a motor 4 drives the impeller 2.
It was supposed to rotate at high speed to obtain air volume and vacuum pressure.

Problems to be Solved by the Invention In an electric blower having a structure in which the air guide 3 is provided on the outer periphery of the impeller 2, when the airflow discharged from the impeller 2 flows into the air guide 3, the air guide inlet The noise thought to be caused by collisions was a problem. This occurs as a product of the number Z of the impeller 20 blades and the rotation speed N (r, pom) of the impeller 2, and is commonly called NZ sound.

The present invention is intended to solve these problems, and aims to reduce noise by improving the diffuser section of the air guide itself.

Means for Solving the Problems The technical means of the present invention for solving the above problems is to provide a rib in the diffuser of the air guide to form a space between it and the casing, and to provide a communication part in the rib. It was established.

Effect This technical means works as follows. That is, the space formed by the ribs and the casing forms a resonant muffler, and the noise generated by the impeller is reduced by this resonant muffler.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In FIGS. 1 to 4, 21 is a casing, and an intake hole 22 is opened in the center. Further, the opposite side of the intake port 22 contains an impeller and an air guide, which will be described later, and is attached to the motor frame 23 so as to prevent air leakage. 2
4 is a centrifugal impeller having a plurality of blades, and is driven by a motor 32. On the outer periphery of this impeller 24,
A plurality of diffusers 26 are provided to recover the pressure of the airflow sent out from the impeller 24 (eight in the embodiment), and a return passage 28 that communicates with the diffusers 26 and guides the airflow to the motor intake hole 27 There is. The diffuser 26 and the return passage 28 are formed in the air guide 25. Diffuser 2 of the air guide 26 above
6 is provided with an annular rib 29 on its upper part, and forms a space 30 with the casing 21. This space portion 30 is connected to the diffuser 26 through a communication portion 31 provided in the rib 29. This communication portion 31 is a round hole as shown in FIG. In this example, the round hole diameter φ
2.6 and there are 63 pieces lined up on the circumference.

Next, the operation of the configuration of this embodiment will be explained. The airflow discharged from the impeller 24 flows into the diffuser 26 of the air guide 26 and the pressure is recovered. The airflow then flows over the upper surface of the diffuser 26 as indicated by the arrows in FIGS. 2 and 4, flows into the return passage 28, and enters the motor 32.

When airflow flows through this diffuser 26, the space 30 on the outer periphery plays the role of a resonant muffler with the communication section 31 as an inlet (-1) to reduce the noise contained in the airflow. The sound at the frequencies that occur is greatly reduced, making it possible to obtain a quiet fan.

Furthermore, filling this space 30 with soundproofing material further enhanced the effect. In this example, urethane was used as the soundproofing material, but there is no particular limitation.

Further, the shape of the communicating portion 31 may be formed into a slit shape as shown in FIG. 5, but is not particularly limited.

Further, in the embodiment of the present invention, an annular rib 29 is installed on the upper part of the diffuser 26. Therefore, the lower end of the rib 29 is connected to the diffuser 2 as shown in FIG.
It has a complex shape along the slope of 6. However, as shown in FIG.
It is also conceivable to provide the air guide 25 on the outer periphery of the motor frame 2.
It has a simple shape that can be placed on the flat surface of No. 3.

Incidentally, in any of the embodiments, the rib 29 may be formed integrally with the air guide 25.

Effects of the Invention In the present invention, since a rib is provided in the diffuser part of the air guide and a space is provided between it and the casing, the contact surface between the rib and the airflow is large, and noise can be significantly reduced. This can be theoretically proven to be effective as a resonant silencer, and its practical effects are great.

[Brief explanation of the drawing]

FIG. 1 is a partially cutaway side view of an electric blower showing an embodiment of the present invention, and FIG. 2 is a plan view of the air guide.
3 is a sectional view taken along the line A-A in FIG. 2, FIG. 4 is a side view taken from the direction B in FIG. 2, FIG. 5 is a side view of another embodiment corresponding to FIG. 4, and FIG. FIG. 7 is a partial sectional view showing still another embodiment, and is an exploded perspective view of a conventional electric blower. 21... Casing, 24... Impeller, 25... Air guide, 26... Diffuser, 29... Rib, 30... ...
Space section, 31... communication section. Name of agent: Patent attorney Toshio Nakao and 1 other person30
-Kenjitsu Figure 4 Figure 5 Figure 6 Figure 23 Mo! -717-mu

Claims (2)

[Claims] (1) a centrifugal impeller driven by a motor; an air guide having a plurality of diffusers that recover the pressure of the airflow sent out from the impeller; and a plurality of return passages that guide the airflow to the motor; 1. An electric blower comprising: a casing containing an air guide; a diffuser of the air guide is provided with a rib having a communicating portion; and a space is formed between the rib and the casing. (2) The electric blower according to claim 1, wherein a soundproofing material is provided in the space.