JPH04311698A - Motor fan - Google Patents

Abstract

PURPOSE:To provide a motor fan enabling the reduction of passage loss in an air guide. CONSTITUTION:There are provided a motor 25, and a casing 21 for enclosing an impeller 23 and an air guide 24, with a suction part provided at its center. A blade 23a forming the impeller 23 is placed inward from the outer peripheral end of a front face shroud 23b or a rear face shroud 23c, and the entrance part of the diffuser blade 24b of the air guide 24 is extended as far as around the exit of the blade 23a of the impeller 23, without coming in contact with the front face shroud 23b or the rear face shroud 23c.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric blower used in a vacuum cleaner.

0002

BACKGROUND OF THE INVENTION In recent years, vacuum cleaners using electric blowers have tended to have higher output in order to be used for cleaning carpets and sucking in dust mites. A conventional electric blower will be explained below based on FIGS. 8 and 9. A casing 1 houses an air guide 2 and an impeller 3, and is airtightly attached to a motor 4. The impeller 3 is composed of a blade 5, a front shroud 6 sandwiching the blade 5, and a rear shroud 7.

With the above configuration, the impeller 3 is rotated at high speed by the motor 4, and the required air volume and vacuum pressure are obtained by the generated centrifugal force.

0004

[Problems to be Solved by the Invention] In the electric blower having the conventional configuration described above, when the airflow flows from the outlet of the impeller 3 to the air guide 2, there is a gap between the casing 1 and the impeller 3 and a gap between the impeller 3 and the air guide 2. Airflow flows in through the gap between the air guides 2 and 2, and turbulence occurs in the upper and lower portions of the diffuser 8 of the air guide 2. This turbulence in airflow causes passage loss, reducing the efficiency of the electric blower. Further, wind noise caused by the blade 5 was generated, which caused a harsh noise.

[0005] Therefore, the present invention is an attempt to solve the problems that such conventional configurations had, and its primary purpose is to provide an electric blower that can reduce passage loss due to airflow. It is. In addition to the first object, a second object is to provide an electric blower that can reduce wind noise caused by high-speed airflow.

[0006]

[Means for Solving the Problems] A first means of the present invention for achieving the first object includes a motor, a casing containing an impeller and an air guide, and a casing having a suction portion in the center thereof, The blades constituting the air guide are at least inside the outer peripheral edge of the front shroud or the rear shroud, and the inlet portion of the diffuser blade of the air guide extends to the vicinity of the impeller blade outlet without contacting the front shroud or the rear shroud. This is an electric blower.

A second means of the present invention to achieve the second object is, in addition to the configuration of the first means of the present invention described above, to provide an inlet portion of the diffuser blade of the air guide with an inclined or curved shape. This is an electric blower.

[0008]

[Operation] The first means of the present invention is to extend the inlet portion of the diffuser blade of the air guide to the vicinity of the impeller blade outlet without contacting the front shroud and the rear shroud. Therefore, the high-speed airflow discharged from the impeller smoothly flows into the diffuser of the air guide without being subjected to disturbance, and passage loss is significantly reduced.

The second means of the present invention is that the inlet portion of the diffuser blade of the air guide is formed into an inclined or curved shape, so that the entire high-speed airflow discharged from the impeller collides with the inlet portion of the diffuser blade at the same time. will disappear. In addition, because the inlet of the diffuser blade is located between the front shroud and the rear shroud,
The airflow passage area does not suddenly expand and there is almost no decrease in efficiency. Therefore, the generation of wind noise can be suppressed.

0010

[Example] The following is an example of the first means of the present invention as shown in FIG.
This will be explained based on FIGS. 2, 3, and 4. 21 is a casing, which has an intake hole 21a in the center. Casing 2
1 has an impeller 23 and an air guide 24 inside, and is attached to a motor frame 22 of a motor 25 on the opposite side of the intake hole 21a so as to prevent air leakage. Further, the impeller 23 includes a plurality of blades 23a, a front shroud 23b, and a rear shroud 23c. The air guide 24 guides the high-speed airflow discharged from the impeller 23 to the motor intake hole 25b of the motor 25. The air guide 24 includes a diffuser 24a that is formed by the air guide 24 and the casing 21 and has a passage that expands toward the outer periphery, and diffuser blades 24b. A return passage 24c smoothly communicates with the end of the diffuser 24a, and guides the airflow to the motor intake hole 25b. The motor 25 described above is a commutator motor in this embodiment, and the airflow flowing into the motor intake hole 25b is discharged from the exhaust hole 25c while cooling the inside of the motor 25. The blades 23a constituting the impeller 23 are attached to the front shroud 23.
b. It is located inside the outer peripheral end of the rear shroud 23c. Also, the diffuser blade 24b of the air guide 24
The entrance part of the front shroud 23b and the rear shroud 2
blades 23 of impeller 23 without contacting 3c.
It has a configuration in which it extends to the vicinity of the exit a. In other words, in this example, the penetration from the shroud surface is 2 m in diameter.
The setting is m. FIG. 2 shows the structure of the impeller 23 and the air guide 24 viewed from above, and the tiffuser blade 24b is inserted into the impeller 23. In this embodiment, the number of blades 23a constituting the impeller 23 is nine, but there is no particular restriction on the number of blades. Similarly, there is no limit to the number of air guides 24. Also, the assembly is done by the diffuser blade 24b
The impeller 23 is forcibly expanded from the diameter of the impeller 23 using a ring-shaped jig, and then the impeller 23 is assembled, and then this jig is removed.

The operation of this embodiment will be explained below with reference to FIG. The high-speed airflow discharged from the impeller 23 smoothly flows into the diffuser 24a because the inlet portion of the diffuser blade 24b extends to the vicinity of the outlet of the blade 23a of the impeller 23. At this time, the high-speed airflow flows through the front shroud 23b and the rear shroud 2.
3c exists, there are almost no gaps, and there is no influence from the outside on the airflow. Also, front shroud 2
3b and rear shroud 23c suppress expansion of the airflow passage area. Therefore, the high-speed airflow discharged from the impeller 23 flows into the diffuser 24a without causing a rapid expansion of the passage area. Air flow is impeller 23
When it is discharged outside, it is decelerated and is hardly affected by the gap.

As described above, according to this embodiment, there is no turbulence due to airflow leaking from the gap, and loss due to sudden expansion is suppressed, so passage loss can be reduced and efficiency can be improved.

5 and 6 show other embodiments. In the configuration shown in FIG. 5, the blades 23a constituting the impeller 21 are placed inside the outer peripheral end of the rear shroud 23c, and the inlet portion of the diffuser blade 24b constituting the air guide is not brought into contact with the rear shroud 23c.
This is an electric blower that extends to the vicinity of the blade outlet of the impeller 21. In addition, the configuration shown in Figure 6 is
The blades 23a constituting the impeller 21 are located inside the outer peripheral end of the front shroud 23b, and the inlet portion of the diffuser blade 24b constituting the air guide is extended to the vicinity of the blade outlet of the impeller 21 without contacting the front shroud 23b. This is an electric blower.

Even with the above configuration, the object of the first means of the present invention can be fully achieved.

Next, an embodiment of the second means of the present invention will be explained based on FIG. The configuration of this embodiment is the same as the embodiment of the first means, and the inlet portion 24c, that is, the end portion of the diffuser blade 24b of the air guide 24 is set to have an inclined or curved shape.

The operation of this embodiment will be explained below. When high-speed airflow is discharged from the impeller 23, wind noise is generated when it enters the diffuser blade 24b. In the embodiment of the first means, since the inlet portion of the diuser blade 24b is straight, the entire high-speed airflow discharged from the impeller 23 flows into the diuser blade 24b almost simultaneously, producing a harsh noise. I have issues. In this embodiment, the diffuser blade 24
Since the inlet portion 24c of the diffuser blade 24c is inclined, that is, retreated toward the outer circumference from the top to the bottom, the discharged high-speed airflow gradually flows into the diffuser blade 24b.

According to the results of experiments, the rotation speed of the configuration of this embodiment is 35,000 r/min. Since the number of blades 23a constituting the impeller 23 is nine, 5.
Generates noise with a peak at 25kHz. The magnitude of this noise is approximately 5% higher at the peak value than that of the conventional configuration.
I was able to lower it by dB. In addition, efficiency is improved due to the presence of the front shroud 23b and rear shroud 23c.
No air leakage occurred and there was almost no effect.

As described above, according to this embodiment, it is possible to reduce harsh noise without reducing efficiency.

[0019]

As described above, according to the first means of the present invention, the blades are located on the inner peripheral side from the outer peripheral ends of the front and rear shrouds of the impeller, and the diffuser blades of the air guide are located opposite to the blades. By extending the inlet portion to the vicinity of the impeller blade outlet without contacting the front and rear shrouds, passage loss can be significantly reduced and a highly efficient electric blower can be achieved.

The second means of the present invention is that the inlet portion of the diffuser blade of the air guide is formed into an inclined or curved shape, so that the high-speed airflow coming out of the impeller blades does not collide with the inlet portion of the diffuser blade at the same time. Therefore, it is possible to create an electric blower that can reduce wind noise and reduce harsh noise.

[Brief explanation of drawings]

FIG. 1 is a partial sectional view of an electric blower in an embodiment of the first means of the present invention.

[Figure 2] Plan view of the impeller and air guide of the electric blower of the same example

[Fig. 3] Enlarged sectional view of main parts explaining the operation of the same embodiment

[Figure 4] Cross-sectional view of the electric blower in the same example

[Fig. 5] Partial cross-sectional view of the electric blower showing the second embodiment.

[Fig. 6] Partial cross-sectional view of the electric blower showing the third embodiment.

FIG. 7 is a partial sectional view of an electric blower that is an embodiment of the second means of the present invention.

[Figure 8] Cross-sectional view of a conventional electric blower

[Figure 9] Partial cross-sectional view explaining the operation of a conventional electric blower

[Explanation of symbols]

21 Casing 23 Impeller 23a Blade 23b Front shroud 23c rear shroud 24 Air guide 24b Diffuser blade 25 Motor

Claims (2)

[Claims] Claim 1: A motor, a casing that encloses an impeller and an air guide and has a suction section in the center, wherein the blades constituting the impeller are located inside the outer peripheral edge of at least a front shroud or a rear shroud, and An electric blower in which the inlet part of the diffuser blade of the guide extends to the vicinity of the impeller blade outlet without contacting the front shroud or rear shroud. 2. The electric blower according to claim 1, wherein the inlet portion of the diffuser blade of the air guide has an inclined or curved shape.