WO2018003017A1

WO2018003017A1 - Electric blower and electric vacuum cleaner

Info

Publication number: WO2018003017A1
Application number: PCT/JP2016/069150
Authority: WO
Inventors: 奈穂安達; 池田　尚史; 光将浜崎
Original assignee: 三菱電機株式会社; 三菱電機ホーム機器株式会社
Priority date: 2016-06-28
Filing date: 2016-06-28
Publication date: 2018-01-04
Also published as: TWI619465B; TW201800048A; JPWO2018003017A1; JP6636150B2

Abstract

The purpose of the present invention is to provide an electric blower that is highly efficient even with a small diameter and an electric cleaner equipped with the electric blower. The present invention is equipped with a centrifugal impeller (11), an electric motor (9), and a diffuser (15) disposed between the centrifugal impeller (11) and the electric motor in the direction of the rotating shaft of the centrifugal impeller (11). The diffuser (15) includes a main plate (14) and a plurality of stator blades (12) and a plurality of return stator blades (13) that are disposed on the main plate. The main plate comprises a connecting section (14A) that is located further toward the outer circumference side, relative to the rotating shaft, than the centrifugal impeller (11) and that is connected to the plurality of stator blades. Each of the plurality of stator blades comprises an outer circumference section (12B) that is located farther from the rotating shaft than the connecting section. Each of the outer circumference sections of the plurality of stator blades comprises an extension section (23) that extends further toward the electric motor side than the connecting section of the main plate in the abovementioned direction. The ratio D0/D1 of the diameter D0 of a circle internally tangential to an outer edge section of the main plate to the diameter D1 of a circle externally tangential to the outer circumference sections of the plurality of stator vanes is greater than 0.9.

Description

Electric blower and vacuum cleaner

This invention relates to an electric blower and a vacuum cleaner.

Conventionally, an electric blower used for a vacuum cleaner is known. The conventional electric blower includes an electric motor, a centrifugal impeller, and a diffuser between the electric motor and the centrifugal impeller. The diffuser has a diffuser vane provided on the centrifugal impeller side and a return guide vane provided on the electric motor side. Between the fan casing and the diffuser, from the gap that forms the flow path from the diffuser vane side to the return guide vane side, and from the outer peripheral end of the diffuser (the outer peripheral end of the partition plate that partitions the diffuser vane side and the return guide vane side) A recess reaching the outer peripheral surface of the diffuser vane is provided. Further, there is an apparatus in which the outer diameter of the return guide vane is made smaller than the outer diameter of the diffuser vane to reduce the air flow resistance from the diffuser vane side to the return guide vane (for example, Japanese Patent Laid-Open No. 10-71107). (See Patent Document 1), pages 5-7 and FIG. 1).

JP-A-10-71107

As shown in Patent Document 1, the conventional electric blower is provided such that the flow path rapidly expands between the rear edge of the diffuser vane and the front edge of the return guide vane. For this reason, the conventional electric blower becomes unstable because the pressure on the downstream side of the trailing edge of the diffuser vane rises, causing local backflow in the flow between the vanes of the diffuser vane. There was a problem that it was easy to stall when it was on the air volume side. In addition, there is a problem that the degree of reduction in efficiency due to the local backflow as described above becomes particularly large in the electric blower with a reduced diameter.

The present invention has been made to solve the above-described problems, and a main object of the present invention is to provide a highly efficient electric blower and a vacuum cleaner including the same even if the diameter is reduced. .

The electric blower according to the present invention includes a centrifugal impeller, an electric motor that rotates the centrifugal impeller, and a diffuser provided between the centrifugal impeller and the electric motor in a direction along the rotation axis of the centrifugal impeller. The diffuser includes a main plate provided between the centrifugal impeller and the electric motor in the direction, a plurality of stationary blades provided in an annular shape on a surface of the main plate facing the centrifugal impeller in the direction, and the main plate in the direction. And a plurality of return vanes provided in an annular shape on the surface facing the electric motor. The main plate has a connecting portion that is located on the outer peripheral side of the centrifugal impeller and is connected to a plurality of stationary blades. Each of the plurality of stationary blades has an outer peripheral portion located on the outer peripheral side with respect to the connecting portion. Each of the outer peripheral portions of the plurality of stationary blades has an extending portion that extends toward the electric motor side of the connecting portion of the main plate in the above direction. The ratio D0 / D1 of the diameter D0 of the circle inscribed in the outer edge portion of the main plate to the diameter D1 of the circle inscribed on the outer peripheral portions of the plurality of stationary blades exceeds 0.9.

According to the present invention, it is possible to provide a highly efficient electric blower and a vacuum cleaner including the same even if the diameter is reduced.

It is a schematic diagram which shows the electric vacuum cleaner which concerns on Embodiment 1. FIG. 1 is a cross-sectional view showing an electric blower according to Embodiment 1. FIG. 3 is a plan view showing a diffuser of the electric blower according to Embodiment 1. FIG. It is a perspective view of the diffuser shown in FIG. In the electric blower according to Embodiment 1, it is a graph showing the relationship between the ratio D0 / D1 of the minimum value of the outer diameter of the main plate to the maximum value of the outer diameter of the stationary blade and the efficiency of the electric blower. It is sectional drawing which shows the electric blower which concerns on Embodiment 2. FIG. 6 is a plan view showing a diffuser of an electric blower according to Embodiment 3. FIG. It is a top view which shows the diffuser of the electric blower which concerns on Embodiment 4. It is a top view which shows the comparative example for demonstrating the effect of the electric blower which concerns on Embodiment 4. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following drawings, the same or corresponding parts are denoted by the same reference numerals, and description thereof will not be repeated.

Embodiment 1 FIG.
<Configuration of electric vacuum cleaner>
Drawing 1 is a mimetic diagram of a vacuum cleaner concerning an embodiment. In FIG. 1, the present vacuum cleaner includes a vacuum cleaner body 1, a suction part 4, a dust collection part 5, an electric blower 6 and a discharge port 7. The suction part 4 is connected to the main body 1 of the electric vacuum cleaner by a hose 2 and an extension pipe 3 as a pipe line, and sucks air in the part to be cleaned. The hose 2 is connected to the main body 1 of the vacuum cleaner. The extension pipe 3 is connected to the tip end side of the hose 2. The suction part 4 is connected to the tip part of the extension pipe 3. The dust collecting unit 5 is provided inside the vacuum cleaner main body 1, communicates with the suction unit 4, and stores sucked air dust. The electric blower 6 is provided inside the vacuum cleaner body 1 and sucks air from the suction part 4 to the dust collecting part 5. The electric blower 6 is an electric blower according to an embodiment of the present invention described later. The discharge port 7 is provided outside the vacuum cleaner main body 1 and discharges the air after being collected by the dust collecting unit 5 to the outside of the vacuum cleaner main body 1. The discharge port 7 is provided in the back of the vacuum cleaner main body 1 as shown in FIG.

In the side part of the vacuum cleaner body 1, rear wheels 8 are arranged on the rear side in the traveling direction. A front wheel (not shown) is provided on the lower side of the vacuum cleaner body 1 on the front side in the traveling direction.

<Configuration of electric blower>
With reference to FIGS. 2 to 5, the electric blower 6 according to the first embodiment includes a centrifugal impeller 11, an electric motor 9, and a diffuser 15. The electric motor 9 includes a shaft 10. The centrifugal impeller 11 is fixed to the shaft 10. The electric motor 9 rotates the centrifugal impeller 11 by rotating the shaft 10. The electric motor 9 is an electric motor such as a motor. The centrifugal impeller 11 and the diffuser 15 are accommodated in the fan cover 16, and form an air path with the fan cover 16. In FIGS. 2 and 4, the arrows indicate the flow of air.

The diffuser 15 forms an air passage in which a cross-sectional area perpendicular to the air flow direction (hereinafter simply referred to as a flow passage area) is gradually enlarged with the fan cover 16. The diffuser 15 includes a plurality of stationary blades 12, a plurality of return stationary blades 13, and a main plate 14. The main plate 14 is provided between the centrifugal impeller 11 and the electric motor 9 in a direction along the rotational axis O of the centrifugal impeller 11 (hereinafter simply referred to as a rotational axis direction). The main plate 14 has a connecting portion 14 A that is located on the outer peripheral side of the centrifugal impeller 11 and connected to the plurality of stationary blades 12. The main plate 14 has a surface facing the centrifugal impeller 11 and a surface facing the electric motor 9 in the rotation axis direction. The connecting portion 14 A has an outer edge portion 14 o located on the outer peripheral side of the main plate 14. In plan view from the direction of the rotation axis, the planar shape of the main plate 14 is a substantially polygonal shape. The main plate 14 has a relatively long portion and a short portion from the rotation axis O to the outer edge portion 14o. In the main plate 14, relatively long portions and short portions from the rotation axis O to the outer edge portion 14 o are alternately formed in the rotation direction of the centrifugal impeller 11. The planar shape of the main plate 14 is such that, for example, a portion where the distance from the rotation axis O to the outer edge portion 14o is relatively long forms an apex whose inner angle is less than 180 degrees, and the distance from the rotation axis O to the outer edge portion 14o is relative. Therefore, the short part is provided so as to form a vertex whose inner angle exceeds 180 degrees. In addition, the planar shape of the main plate 14 may be provided such that only a portion where the distance from the rotation axis O to the outer edge portion 14o is relatively long forms a vertex.

The plurality of stationary blades 12 are provided in a ring shape on the surface facing the centrifugal impeller 11 of the connecting portion 14 A of the main plate 14. That is, the plurality of stationary blades 12 are arranged on the outer peripheral side with respect to the centrifugal impeller 11.

Each of the plurality of stationary blades 12 includes a first portion 12A located on the connecting portion 14A of the main plate 14 and a second portion 12B (outer periphery) located on the outer peripheral side with respect to the rotation axis O than the connecting portion 14A of the main plate 14. Part). That is, the diameter D1 of the circle C1 circumscribing each second portion 12B of the plurality of stationary blades 12 around the rotation axis O is larger than the maximum value of the outer diameter of the main plate 14. Each of the plurality of stationary blades 12 has an inner edge portion 12i where the first portion 12A is located on the inner peripheral side, and an outer edge portion 12o where the second portion 12B is located on the outer peripheral side.

Each of the second portions 12B of the plurality of stationary blades 12 has an extending portion 23 that extends toward the electric motor 9 from the connecting portion 14A of the main plate 14 in the rotational axis direction. That is, the second portion 12B has a portion that is longer in the rotation axis direction than the first portion 12A.

2, 3 and 5, the diameter D0 of the circle C0 inscribed in the outer edge portion 14o of the main plate 14 with respect to the diameter D1 of the circle C1 circumscribed in the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12. The ratio D0 / D1 is over 0.9 (D0 / D1> 0.9). A circle C0 that is inscribed in the outer edge portion 14o of the main plate 14 with the rotation axis O as the center is inscribed in a portion of the main plate 14 that has a relatively short distance from the rotation axis O to the outer edge portion 14o.

The plurality of return vanes 13 are provided in an annular shape on the surface of the main plate 14 located on the motor 9 side in the rotation axis direction. Outer edge part 13o located in the outermost peripheral side in a plurality of return vanes 13 is located in the inner peripheral side rather than outer edge part 14o of main board 14, for example.

At the upper part of the centrifugal impeller 11, a fan cover 16 that includes the centrifugal impeller 11 and the stationary blade 12 of the diffuser 15 is provided. An opening and a bell mouth 18 are provided in the center of the fan cover 16 at a position facing the suction port 17 of the centrifugal impeller 11. In the cross section perpendicular to the rotation axis direction, the inner peripheral surface of the fan cover 16 is provided in a circular shape, for example.

On the side of the electric blower 6, there are provided a bracket 19 that is connected to the fan cover 16 and encloses the return vane 13, and a motor frame 20 that is connected to the bracket 19 and encloses the electric motor 9.

Between the fan cover 16 and the diffuser 15, a gap 21 serving as a gas flow path from the stationary blade 12 to the stationary blade 13 side is provided on the outer peripheral side of the stationary blade 12. The motor frame 20 is provided with several discharge holes 22 through which the air that has passed through the centrifugal impeller 11, the diffuser 15, and the electric motor 9 is discharged.

<Operation of electric blower>
In the electric blower 6, when electric power is supplied to the electric motor 9, the centrifugal impeller 11 attached to the shaft 10 rotates and sucks air into the bell mouth 18 from the suction port 17. The air sucked into the bell mouth 18 by the centrifugal impeller 11 is boosted and accelerated by the centrifugal impeller 11, and a plurality of air positioned on the outer peripheral side with respect to the rotation axis O from the centrifugal impeller 11 while turning. It flows between the blades of the stationary blade 12. Thereafter, the air is pressurized and decelerated between the blades of the plurality of stationary blades 12. Further, the air passes through the gap 21 between the diffuser 15 and the fan cover 16, is guided to the electric motor 9 side by the return stationary blade 13, and cools the electric motor 9. Thereafter, air is discharged from the discharge hole 22 provided in the motor frame 20 to the outside of the electric blower.

<Effects of electric blower>
The electric blower 6 has the second part 12B (outer peripheral part) in which the stationary blade 12 is positioned on the outer peripheral side with respect to the rotation axis O with respect to the connecting portion 14A of the main plate 14, and therefore the stationary blade is the second part 12B. Compared with a conventional electric blower that does not have a vortex, it is possible to reduce the ventilation resistance of the air passage that passes between the plurality of stationary blades 12 and moves between the plurality of return stationary blades 13. Furthermore, since each of the second portions 12B of the plurality of stationary blades 12 has an extending portion 23 that extends toward the electric motor 9 with respect to the connecting portion 14A of the main plate 14 in the rotational axis direction, Compared with the conventional electric blower that does not have the extension 23, while reducing the draft resistance of the air path that passes between the plurality of stationary blades 12 and between the plurality of return stationary blades 13, the stationary blade 12 and the return The local backflow between the stationary blade 13 can be prevented.

Further, in the electric blower 6, the ratio D0 / D1 of the diameter D0 of the circle C0 inscribed in the outer edge portion 14o of the main plate 14 to the diameter D1 of the circle C1 circumscribed in the second portions 12B of the plurality of stationary blades 12 exceeds 0.9. It is. FIG. 5 is a graph showing the relationship between the ratio D0 / D1 obtained by numerical analysis and the blower efficiency for an electric blower having the same configuration as the electric blower 6 except for the ratio D0 / D1. The horizontal axis in FIG. 5 indicates the ratio D0 / D1, and the vertical axis in FIG. 5 indicates the efficiency of the electric blower. As shown in FIG. 5, the electric blower 6 configured such that the ratio D0 / D1 exceeds 0.9 is an electric blower configured such that the ratio D0 / D1 is 0.9 or less. In comparison, it was confirmed that the efficiency was high. This is considered to be due to the following reason.

When the diameter D0 of the circle C0 inscribed in the outer edge portion 14o of the main plate 14 becomes relatively smaller than the diameter D1 of the circle C1 circumscribed in the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12, the plurality of stationary blades The area on the plane perpendicular to the rotation axis direction of the gap 21 formed on the air path that passes between 12 and between the plurality of return vanes 13 increases. Therefore, the influence which the said area of the clearance gap 21 has on the ventilation resistance of the electric blower 6, a work rate, and efficiency becomes large. Specifically, when the area of the gap 21 is increased, the ventilation resistance of the air path that passes between the plurality of stationary blades 12 and between the plurality of return stationary blades 13 is reduced, and the efficiency is improved. However, when the ratio D0 / D1 is 0.9 or less and the area of the gap 21 is configured to be a predetermined size or more, a part of the air flowing between the plurality of stationary blades 12 is stationary blades. Before reaching the outer edge portion 12o of 12, the flow returns from the gap 21 and flows into the stationary blade 13 side, so that a sufficient amount of pressure increase between the stationary blades 12 cannot be secured, and the efficiency is lowered. This reduction in efficiency is particularly problematic on the low air volume side where the wind speed in the radial direction of the centrifugal impeller 11 is slow.

On the other hand, since the electric blower 6 is configured such that the ratio D0 / D1 exceeds 0.9, most of the air flowing between the plurality of stationary blades 12 reaches the second portion 12B and is not a gap. 21 returns to the stationary vane 13 side. Therefore, in the electric blower 6, since the air that has passed between the first portions 12A and the second portions 12B of the plurality of stationary blades 12 returns from the gap 21 and flows between the stationary blades 13, the passage resistance of the air passage is reduced. In addition, the amount of pressure increase between the stationary blades 12 is ensured. As a result, the electric blower 6 is highly efficient even when the diameter is reduced.

<Specific example of electric blower>
Next, a specific example of the electric blower 6 will be described with reference to FIGS. The electric blower 6 may further include the following configuration in addition to the above configuration.

As shown in FIG. 2, the outer edge portion 14o located on the outermost peripheral side with respect to the rotational axis O in the connecting portion 14A of the main plate 14 is a portion located on the innermost peripheral side with respect to the rotational axis O in the connecting portion 14A. That is, the connecting portion 14A may be located closer to the electric motor 9 in the rotational axis direction than the portion 14i connected to the inner edge portion 12i of the stationary blade 12. If it says from a different viewpoint, 14 A of connection parts incline with respect to the rotating shaft O so that it may go to the motor 9 side in the rotating shaft direction toward the outer edge part 14o from the said part 14i.

In this way, the width of the air passage formed between the plurality of stationary blades 12 and the fan cover 16 can be gradually increased in the radial direction of the centrifugal impeller 11 and in the direction of the rotation axis. Can also be gradually expanded. For this reason, the electric blower 6 configured in this manner is provided between the plurality of stationary blades 12 and the fan cover 16 as compared with the electric blower 6 having a configuration in which the width of the air passage is gradually enlarged only in the radial direction. Since the area of the air passage formed therebetween can be increased and the amount of pressure increase in the air passage can be increased, the efficiency is high.

As shown in FIG. 2, the extending portion 23 includes an end portion of the extending portion 23 located on the electric motor 9 side in the rotating shaft direction, and a portion (outer edge) located farthest from the rotating shaft O in the connecting portion 14A. The distance in the direction of the rotation axis between the portion 14o) and the portion 14o) may be configured to increase toward the outer peripheral side.

In this way, even when the operating condition of the electric blower 6 is on the relatively low air volume side, air can be smoothly guided from between the stationary blades 12 to the stationary blades 13 to reduce passage resistance. be able to. Therefore, such an electric blower 6 is highly efficient because the amount of power required for operation is reduced.

<Operation and effect of vacuum cleaner>
Next, the operation of the vacuum cleaner will be described. In the electric vacuum cleaner configured as described above, when electric power is supplied to the electric motor 9, the shaft 10 rotates. As the shaft 10 rotates, the centrifugal impeller 11 attached to the shaft 10 rotates and sucks air from the suction port 17. Thereby, the air on the surface to be cleaned is sucked into the vacuum cleaner body 1 through the hose 2, the extension pipe 3, and the suction portion 4 connected to the vacuum cleaner body 1. The air sucked into the electric vacuum cleaner main body 1 is collected in the dust collecting unit 5. Thereafter, the air discharged from the dust collecting unit 5 passes through the bell mouth 18 of the electric blower 6 and is sucked from the suction port 17 of the centrifugal impeller 11. The air sucked into the centrifugal impeller 11 is increased in pressure and accelerated by the centrifugal impeller 11, and travels radially outward while turning. Most of the air discharged from the centrifugal impeller 11 is decelerated and boosted between the vanes of the stationary blade 12 of the diffuser 15. Thereafter, the air passes through the gap 21 between the diffuser 15 and the fan cover 16. Further, the air is guided to the electric motor 9 side by the return vane 13 to cool the electric motor 9. Thereafter, air is discharged from the discharge hole 22 provided in the motor frame 20 to the outside of the electric blower. And air is discharged | emitted from the discharge port 7 provided in the vacuum cleaner main body 1 to the outer side of the vacuum cleaner main body 1. FIG.

Since the above-described electric vacuum cleaner uses the electric blower 6 having the above-described configuration, a small and highly efficient electric blower and vacuum cleaner can be obtained.

Embodiment 2. FIG.
Next, an electric blower 60 according to Embodiment 2 will be described with reference to FIG. The electric blower 60 basically has the same configuration as the electric blower 6 according to the first embodiment, but the connecting portion 14A of the main plate 14 is curved toward the electric motor 9 in the rotation axis direction. It differs in that it has 25. In FIG. 6, arrows indicate the air flow.

The plurality of stationary blades 12 may not be connected to the lower edge portion 14u in the rotation axis direction of the main plate 14, for example. Each of the second portions 12B (outer peripheral portions) of the plurality of stationary blades 12 extends to the electric motor 9 side with respect to the connecting portion 14A connected to the plurality of stationary blades 12 in the rotation axis direction. have. A portion (inner edge portion) located on the innermost peripheral side in the extending portion 23 is connected to, for example, a portion located between the lower edge portion 14 u of the main plate 14 and the curved portion 25. The portion (outer edge portion) located on the outermost peripheral side in the extension portion 23 is located closer to the motor 9 in the rotation axis direction than the inner edge portion of the extension portion 23, and preferably the lower edge portion 14 u of the main plate 14. It is located on the electric motor 9 side in the rotation axis direction.

The plurality of return vanes 13 are connected to a portion of the main plate 14 located on the inner peripheral side of the curved portion 25.

Even in this case, the electric blower 60 basically has the same configuration as the electric blower 6, and therefore, the same effect as the electric blower 6 can be obtained. Further, since the electric blower 60 has the curved portion 25 in which the connecting portion 14A of the main plate 14 is curved toward the side opposite to the centrifugal impeller 11, the main plate 14 does not have the curved portion 25 and is a flat plate. Compared with the electric blower 6 provided in a shape, the main plate 14 has a high strength and exhibits a high strength against deformation such as twisting.

Embodiment 3 FIG.
Next, an electric blower according to Embodiment 3 will be described with reference to FIG. The electric blower according to the third embodiment basically has the same configuration as the electric blower 6 according to the first embodiment, but the planar shape of the main plate 14 is circular in a plan view from the rotation axis direction. It is different. In FIG. 7, arrows indicate the air flow.

In this way, the distance between the outer edge portion 14o of the main plate 14 and the inner peripheral surface of the fan cover 16 can be made constant in the rotational direction. Therefore, the planar shape of each gap 21 formed between the fan cover 16 and the diffuser 15 is made uniform in a plan view from the rotation axis direction. As a result, the electric blower according to Embodiment 3 is more efficient than the electric blower 6 because the passage resistance is further reduced.

Embodiment 4 FIG.
Next, an electric blower according to Embodiment 4 will be described with reference to FIG. The electric blower according to the fourth embodiment basically has the same configuration as the electric blower 6 according to the first embodiment, but the second parts 12B (outer peripheral parts) of the plurality of stationary blades 12 are It differs in that it is in contact with the inner peripheral surface. In FIG. 8, arrows indicate the air flow.

Here, the state in which the second portions 12B (outer peripheral portions) of the plurality of stationary blades 12 are in contact with the inner peripheral surface of the fan cover 16 means that the second portion 12B and the fan cover 16 are in contact with each other. Alternatively, the second portion 12B and the fan cover 16 are arranged with a small gap (for example, the interval is 1 mm or less). From a different point of view, the diameter D1 of the circle C1 circumscribing the second part 12B (outer peripheral part) of the plurality of stationary blades 12 with the rotational axis O as the center is on the inner peripheral surface of the fan cover 16 with the rotational axis O as the center. It is substantially equal to the diameter D2 of the inscribed circle C2.

FIG. 9 shows, as a comparative example of the electric blower according to the fourth embodiment, an electric blower diffuser 15 having a configuration in which the second portions 12B of the plurality of stationary blades 12 are not in contact with the inner peripheral surface of the fan cover 16. It is a top view. In FIG. 9, the arrows indicate the flow of air.

As shown in FIG. 9, when the second portions 12 B of the plurality of stationary blades 12 are not in contact with the inner peripheral surface of the fan cover 16, the second portions 12 B of the plurality of stationary blades 12 are the inner periphery of the fan cover 16. A gap 24 is formed between the surfaces. In this case, in addition to the air path Q1 flowing between the stationary blades 12 through the gap 21 and returning between the stationary blades 13, it is adjacent to between the plurality of stationary blades 12 through the gap 24 and previously between the stationary blades 12. An air path Q2 flowing between the stationary blades 12 is formed. The air passing through the air path Q2 merges with the air passing through the air path Q1, and is mixed therewith. When the air passing through the air passage Q1 and the air passing through the air passage Q2 are mixed between the stationary blades 12, the pressurization between the stationary blades 12 is hindered, and the work rate may be reduced.

On the other hand, according to the electric blower according to the fourth embodiment, the gap 24 is not formed between the second portion 12B of the plurality of stationary blades 12 and the inner peripheral surface of the fan cover 16, and thus the plurality of stationary blades 12 are provided. The air flowing between them can return through the gap 21 and flow into the stationary blades 13 without mixing with the air flowing between the adjacent stationary blades 12. As a result, according to the electric blower according to the fourth embodiment, since the pressure increase between the stationary blades 12 is promoted, the power is high and the efficiency is high.

As described above, the electric blower according to the first to fourth embodiments can be mounted on the canister type vacuum cleaner main body 1 to which the hose 2 and the extension pipe 3 are connected as shown in FIG. It is not limited. The electric blower according to Embodiments 1 to 4 can be mounted on a vacuum cleaner body of a vacuum cleaner of another structure, such as a cordless type or a stick type vacuum cleaner in which an extension pipe is connected to the vacuum cleaner body. .

The electric blower according to the first to fourth embodiments is configured as an electric blower including the centrifugal impeller 11 using two-dimensional blades, but the form of the centrifugal impeller 11 is not particularly limited. For example, you may be comprised as an electric blower provided with the centrifugal impeller which uses a three-dimensional wing | blade.

Further, the electric blower according to Embodiments 1 to 4 is not limited to a household or commercial vacuum cleaner, and can be applied to any device using an electric blower such as a hand dryer. As a result, a highly efficient and long-life device can be realized.

Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified. The scope of the present invention is not limited to the above-described embodiment. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

The present invention is particularly advantageously applied to devices using an electric blower such as household and commercial vacuum cleaners and hand dryers.

1 Vacuum cleaner body, 2 hose, 3 extension pipe, 4 suction part, 5 dust collection part, 6,60 electric blower, 7 outlet, 8 rear wheel, 9 electric motor, 10 shaft, 11 centrifugal impeller, 12 stationary blade , 13 Return vane, 12A 1st part, 12B 2nd part, 12i inner edge, 12o, 13o, 14o outer edge, 14 main plate, 14A connecting part, 14u lower edge, 15 diffuser, 16 fan cover, 17 inlet , 18 bell mouth, 19 bracket, 20 motor frame, 21, 24 gap, 22 discharge hole, 23 extension part, 25 bending part.

Claims

A centrifugal impeller,
An electric motor for rotating the centrifugal impeller;
A diffuser provided between the centrifugal impeller and the electric motor in a direction along the rotation axis of the centrifugal impeller,
The diffuser includes a main plate provided between the centrifugal impeller and the electric motor in the direction, and a plurality of stationary blades provided annularly on a surface of the main plate facing the centrifugal impeller in the direction. A plurality of return vanes provided annularly on the surface of the main plate facing the electric motor in the direction,
The main plate has a connecting portion that is positioned on the outer peripheral side with respect to the rotation shaft than the centrifugal impeller and is connected to the plurality of stationary blades,
Each of the plurality of stationary blades has an outer peripheral portion located on the outer peripheral side with respect to the rotation shaft with respect to the coupling portion,
Each of the outer peripheral portions of the plurality of stationary blades has an extending portion that extends to the electric motor side with respect to the connecting portion of the main plate in the direction,
An electric blower in which a ratio D0 / D1 of a diameter D0 of a circle inscribed in the outer edge of the main plate to a diameter D1 of a circle inscribed on the outer peripheral portion of the plurality of stationary blades exceeds 0.9.
The part located farthest from the rotating shaft in the connecting part is located closer to the electric motor in the direction than the part located closest to the rotating shaft in the connecting part. The electric blower described in 1.
The extension portion is configured such that a distance in the direction between an end portion of the extension portion located on the motor side in the direction and a portion farthest from the rotation shaft in the connection portion is an outer peripheral side. The electric blower according to claim 1, wherein the electric blower is configured to increase as it goes toward the center.
The electric blower according to any one of claims 1 to 3, wherein a planar shape of the main plate is a circular shape.
The electric blower according to any one of claims 1 to 4, wherein the connecting portion has a curved portion that is curved toward the electric motor side in the direction.
Further comprising a fan cover that houses the centrifugal impeller and the diffuser inside,
The electric blower according to any one of claims 1 to 5, wherein the outer peripheral portions of the plurality of stationary blades are in contact with an inner peripheral surface of the fan cover.
The vacuum cleaner body,
The vacuum cleaner body is connected to the main body by a pipe line, and a suction part for sucking air of a part to be cleaned;
A dust collection unit that is provided inside the vacuum cleaner main body, communicates with the suction unit, and stores the dust of the sucked air;
An electric vacuum cleaner comprising the electric blower according to any one of claims 1 to 6, which is provided inside the main body of the electric vacuum cleaner and sucks air from the suction part to the dust collecting part.