JPH063198B2 - Electric blower - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an electric blower used for a vacuum cleaner.

2. Description of the Related Art Conventionally, this type of electric blower is disclosed in, for example, Japanese Patent Publication No. 52-491.
No. 68 publication. That is, as shown in FIG. 5, the impeller 2 and the air guide 3 are provided in the casing 1, and the motor 4 rotates the impeller 2 at a high speed to obtain the air volume vacuum pressure.

Problems to be Solved by the Invention With the structure in which the air guide 3 is provided on the outer periphery of the impeller 2 as in the above electric blower, when the airflow discharged from the impeller 2 flows into the air guide 3, Noise, which is thought to be caused by a collision, was a problem. In addition, air flow noise generated by the flow of air flow has been a problem.

The present invention solves such a problem, and provides an electric blower that reduces noise without deteriorating the performance of the blower and also considers the configuration and assemblability.

Means for Solving the Problems Technical means of the electric blower of the present invention for solving the above problems are provided with an annular protrusion in the return passage of the air guide, and the air guide is provided on the inner peripheral side of the protrusion. The space portion is formed in cooperation with the motor frame, and the projection portion is provided with a communication hole that connects the space portion and the return passage.

Action This technical means acts as follows. That is, by providing an annular protrusion on the return passage of the air guide and forming a space on the inner peripheral side of the protrusion, the space forms a muffler with the communication hole as an inlet, and the air flow inside the return passage. The noise can be greatly reduced when flowing into the motor.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 4. In the figure, 21 is a casing, and an intake port 22 is opened in the center. The opposite side of the intake port 22 is attached to the motor frame 23 so that there is no air leakage. Reference numeral 24 is a centrifugal impeller having a plurality of blades, and a diffuser 26 formed by a casing 21 and an air guide 25 is arranged on the outer circumference of the impeller 24 so as to have a passage enlarged toward the outer circumference. A return passage 28 is formed on the back surface of the air guide 25 so as to smoothly and independently communicate with the end of the diffuser 26 and guide the airflow to the intake hole 27. Reference numeral 29 is a commutator motor for driving, and the airflow flowing into the motor intake hole 27 is discharged from the exhaust hole 30 while cooling the inside of the motor.

An annular projection 31 is integrally provided in the return passage 28 of the air guide 25, and a communication hole 32 is provided in the projection 31. A space A as a silencer is formed on the inner peripheral side of the protrusion 31 in cooperation with the air guide 25 and the motor frame 23. In the case of the present embodiment, four of the guide walls 33 of the return passage 28 extend to the inner circumference, and consequently four space portions A are formed. The shape of the space A is not limited to that of the embodiment, but may be various shapes. The same applies to the protrusion 31. In addition,
The intake hole 27 is provided in the motor frame 23 outside (outer peripheral side) of the annular protrusion 31.

As can be seen from FIG. 1, in this embodiment, when incorporated with the air guide 25, the space A surrounded by the motor frame 23, the return passage 28 of the air guide, and the protrusion 31 is automatically formed. . The protrusion 3 serves as an inlet of the space A.
That is, the communication hole 32 is provided in 1. In the embodiment, the communication hole 32 provided in the protruding portion 31 is elongated and cut to about half the height of the protruding portion 31, but there is no restriction on the number, size, or shape. Experiments were conducted by arranging φ4 holes instead of the communication holes 32 of the embodiment on the circumference of the protrusion 31 at an equal pitch.
The same muffling effect as in the case of the communication hole 32 was obtained.

Next, the operation of the configuration of this embodiment will be described. Generally, the noise of a fan is transmitted to the outside through a device in which the fan is incorporated, and causes many problems.
As measures against this, measures such as attaching soundproofing materials have been taken, but it is becoming difficult for devices that tend to be miniaturized. Therefore, in the embodiment of the present invention, noise is reduced by the fan itself. Airflow is diffuser 26
When flowing into the return passage 28 from the above and further into the intake hole 27, the space portion A acts as a silencer with the communication hole 32 as an inlet to reduce noise in the air flow. In particular, the space A is provided so that the NZ sound (noise generated by the product of the number of blades Z of the impeller 24 and the number of rotations N) that is a problem for the fan can be silenced
If the shape of is optimized, a great effect can be obtained. In the example, a reduction of about 6 dB was achieved.

Advantageous Effects of Invention The electric blower of the present invention is provided with an annular protrusion in the return passage of the air guide, and a space is formed between the motor frame and the communication hole formed in the protrusion, thereby forming an impeller. The generated NZ noise and the noise in the airflow can be greatly reduced by the action of the silencer in the space. Also, as its structure, it is easy to form the air guide integrally with the air guide simply by providing the protrusion, and the space part as the silencer is automatically formed by simply assembling the air guide at a predetermined position. It can be formed, has excellent assemblability, and has no external appearance that is similar to the conventional electric blower.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view of an electric blower showing an embodiment of the present invention, FIG. 2 is a plan view of a return passage side of the air guide,
FIG. 3 is a plan view of the air guide on the diffuser side, FIG. 4 is a view taken along the line BB in FIG. 2, and FIG. 5 is an exploded perspective view of a conventional electric blower. 23 ... Motor frame, 24 ... Impeller, 25 ...
Air guide, 27 ... Intake hole, 28 ... Return passage, 29
...... Motor, 31 …… Projection, 32 …… Communication hole, A ……
Space section.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Kogei Kato, 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-59-93998 (JP, A)

Claims (1)

[Claims] 1. A motor and a casing mounted on a motor frame of the motor and containing an air guide and an impeller. The air guide is provided with an annular protrusion in its return passage. An electric blower having a space formed on the circumferential side in cooperation with an air guide and a motor frame, and a protrusion provided with a communication hole communicating the space and the return passage.