JPS6242000A - Electric blower - Google Patents

Abstract

PURPOSE:To reduce noise level by furnishing small holes and an enclosed space associate with each of them in those places of an air guide where air stream runs against, and by reducing the sonic energy including a wave of condensation and rarefaction by means of reflection etc. in said enclosed spaces. CONSTITUTION:Air stream in the impeller is eccentrical in such a way as dense in front of each blade in its rotating direction and rare behind. WHen intruding into a diffuser 16, the air stream will become a wave of condensation and rarefaction, and be superposed with sounds originating otherwise to become an air stream with a greater sound level, which will then reach small holes 20. Within an enclosed space 21 adjoining to each of such holes 20, however, the sonic energy of the wave of condensation and rarefaction etc. reduces through reflections etc., and the difference between dense and rare is nullified to cause lessening of sound level. This should accomplish an electric blower with a low noise level.

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 The structure of a conventional electric blower of this type will be explained with reference to FIG.

A centrifugal impeller 3 is fixed to the motor shaft 2 of the drive motor 1, and an air guide 6 in which a diffuser 4 and a return passage 5 following it are integrally formed is provided around the impeller 3, and these impellers 2... The impeller 3 and the air guide 6 are covered with a casing 7, and the impeller 3 is rotated at high speed to obtain air volume and vacuum pressure.

Problems to be Solved by the Invention In such a conventional configuration, there is a problem in that the electric blower generates a lot of noise when operating. This is due to the following reasons.

The airflow discharged from between each blade in the impeller 3 flows into the diffuser 4 in a biased flow state, with a dense flow on the front side of the blades and a sparse flow on the rear side in the direction of rotation. By colliding with the tip of the diffuser wall at the entrance of the diffuser 4, the compressional wave is emphasized and is heard outside as a thick phonetic sound.

The present invention solves these problems and lowers the sound level.

Means for Solving the Problems The technical means of the present invention for solving the above problems are as follows. That is, small holes and 3, in the air guide where the airflow faces.

A closed space is provided next to it.

action The effect of this technical means is as follows.

In other words, the air current with a high sound level, including compressional waves generated by the impeller, flows to a location where there are small holes provided in the air guide. Inside the closed space following the small hole, sound energy including compressional waves is reduced by reflection, etc., and as a result, an electric blower with a low noise level can be obtained.

Embodiments Hereinafter, embodiments of the present invention will be described based on the accompanying drawings.

In FIGS. 1 and 2, 8 is a casing, and an intake port 9 is opened in the center of the casing, and the opposite side of the intake port 9 is attached to the motor frame 10 to prevent air leakage. There is. A centrifugal impeller 12 having a plurality of blades 11 is attached to a motor shaft 13 via a nut (not shown), a spacer 14, and a washer 15.

On the outer periphery of the impeller 12, an air guide 18 is installed, in which a diffuser 16 consisting of a plurality of enlarged passages and a return passage 17 communicating with each enlarged passage of the diffuser 16 are integrally formed.

19 is a motor.

A closed space 21 is provided by closing a recess formed in the wall of the diffuser 16 with a part of the casing 8, and a small hole 2° communicating with the closed space 21 is provided in the wall of the diffuser 16. It is formed.

Next, the operation of this embodiment will be explained. Impeller 1
The airflow inside the flade 11 is biased, with a dense flow on the front side and a sparse flow on the rear side with respect to the direction of rotation of the flade 11. When this air enters the diffuser 16, it becomes a compressional wave, overlaps with the sound generated by other causes, and becomes an airflow with a high sound level, which approaches the small hole 2o.

Inside the closed space 21 following this small hole 2o, the energy of sound such as compressional waves is reduced by reflection, etc., and the level of sound is reduced due to the elimination of the difference in density.

5 to 7' Effects of the Invention As described above, according to the present invention, by providing a small hole and a closed space following the air guide at a location facing the airflow, it is possible to easily replace the conventional air guide by simply replacing the air guide. It is possible to reduce the sound energy that has been a problem since
As a result, it is possible to obtain an electric blower with a low noise level.

[Brief explanation of drawings]

Fig. 1a is a top view of the air guide in an embodiment of the present invention, Fig. 1 is an enlarged top view of section A in Fig. 1, Fig. 2 is a partially cutaway side view showing the overall configuration, and Fig. 3 is a partially cutaway side view of a conventional example. 8... Casing, 12... Impeller, 18... Air guide, 19... Motor, 20... Small hole, 21... Closed space.

Claims (1)

[Claims] It is equipped with a centrifugal impeller, an air guide that guides airflow, a casing that covers the impeller and the air guide, and a motor that drives the impeller, and a small hole and a small hole in the air guide at a place facing the airflow. Electric blower with closed space.