TWI619465B - Electric blower and electric vacuum cleaner - Google Patents

Abstract

Provided are an electric blower with high efficiency even if the diameter is reduced, and an electric vacuum cleaner including the electric blower. The electric blower includes: a centrifugal impeller (11); a motor (9); and a diffuser (15), which is arranged between the centrifugal impeller (11) and the motor in a rotation axis direction of the centrifugal impeller (11). The diffuser (15) includes: a main plate (14); a plurality of stationary blades (12), which are arranged on the main plate (14); and a plurality of returning stationary blades (13). The main board has a connecting portion (14A) which is located on the outer peripheral side of the counter shaft of the centrifugal impeller (11) and is connected to a plurality of stationary blades. Each of the plurality of stationary blades has an outer peripheral portion (12B) located farther from the rotation shaft than the connecting portion. Each of the outer peripheral portions of the plurality of stationary blades has an extension (23) extending in this direction toward the motor side than the connection portion of the main plate. The ratio D0 / D1 of the diameter D0 of the circle inscribed on the outer edge portion of the main board to the diameter D1 of the circle circumscribed on the outer peripheral portion of the plurality of stationary blades exceeds 0.9.

Description

Electric blower and electric vacuum cleaner

The invention relates to an electric blower and an electric vacuum cleaner.

Conventionally, electric blowers used in electric vacuum cleaners are known. Conventional electric blowers include a motor, a centrifugal impeller, and a diffuser located between the motor and the centrifugal impeller. The diffuser has a diffuser blade provided on a centrifugal impeller side and a return guide blade provided on a motor side. Between the fan casing and the diffuser, a gap is provided to serve as a flow path from the diffuser blade side to the return guide vane side; and a recessed portion is provided from the outer peripheral end of the diffuser (to separate the diffuser blade side from the return guide) Lead the outer peripheral end of the partition on the blade side) to the surface on the outer peripheral side of the diffuser blade. In addition, there are those that make the outer diameter of the return guide vane smaller than the smaller diameter of the diffuser vane to reduce the ventilation resistance from the diffuser vane side to the return guide vane (for example, refer to Japanese Patent Application Laid-Open No. 10-71107 (Patent) Reference 1), pages 5 to 7 and 1).

[Leading Patent Literature]

[Patent Literature]

[Patent Document 1] Japanese Unexamined Patent Publication No. 10-71107

As shown in Patent Document 1, a conventional electric blower is provided The flow path rapidly expands from the trailing edge of the diffuser blade to the leading edge of the return guide blade. Therefore, in the conventional electric blower, the flow between the blades of the diffuser blade was partially reversed due to the pressure increase on the downstream side of the trailing edge of the diffuser blade, and the flow became unstable, especially when the operating conditions were on the low air volume side. Vulnerable issues. In addition, the degree of reduction in efficiency caused by local backflow as described above is particularly problematic in that the electric blower is reduced in diameter.

The present invention was developed to solve the problems as described above, and a main object of the present invention is to provide an electric blower with high efficiency even if the diameter is reduced, and an electric vacuum cleaner including the same.

The electric blower of the present invention includes: a centrifugal impeller; a motor for rotating the centrifugal impeller; and a diffuser, which is arranged between the centrifugal impeller and the motor in a direction along the rotation axis of the centrifugal impeller. The diffuser includes: a main plate, which is arranged between the centrifugal impeller and the motor in this direction; a plurality of stationary blades, which are arranged annularly on the surface of the main plate facing the centrifugal impeller in this direction; and a plurality of return static vanes, It is arranged in a ring shape on the surface of the main board facing the motor in this direction. The main board has a connection portion which is located on the outer peripheral side than 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 than the connection portion. Each of the outer peripheral portions of the plurality of stationary blades has an extension portion extending in the direction toward the motor side than the connection portion of the main plate. The ratio D0 / D1 of the diameter D0 of the circle inscribed on the outer edge portion of the main board to the diameter D1 of the circle circumscribed on the outer peripheral portion of the plurality of stationary blades exceeds 0.9.

According to the present invention, it is possible to provide an electric blower with high efficiency even if the diameter is reduced, and an electric vacuum cleaner including the same.

1‧‧‧ Electric vacuum cleaner body

2‧‧‧ hose

3‧‧‧ extension tube

4‧‧‧ Inhalation

5‧‧‧ Dust collection department

6, 60‧‧‧ electric blower

7‧‧‧Exhaust

8‧‧‧ rear wheels

9‧‧‧ Motor

10‧‧‧ axis

11‧‧‧ Centrifugal Impeller

12‧‧‧ static blade

13‧‧‧Reflow static blade

12A‧‧‧Part 1

12B‧‧‧Part 2

12i‧‧‧Inner edge

12o, 13o, 14o‧‧‧‧Edge

14‧‧‧ Motherboard

14A‧‧‧Connection Department

14u‧‧‧ lower edge

15‧‧‧ diffuser

16‧‧‧fan cover

17‧‧‧ Suction port

18‧‧‧bell mouth

19‧‧‧ Bracket

20‧‧‧Motor stand

21, 24‧‧‧ Clearance

22‧‧‧Drain hole

23‧‧‧ extension

25‧‧‧ Bend

Fig. 1 is a schematic diagram showing an electric vacuum cleaner according to a first embodiment.

Fig. 2 is a sectional view showing the electric blower according to the first embodiment.

Fig. 3 is a plan view showing a diffuser of the electric blower according to the first embodiment.

Figure 4 is a perspective view of the diffuser shown in Figure 2.

Fig. 5 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 in the electric blower of the first embodiment, and the relationship between the efficiency of the electric blower.

Fig. 6 is a sectional view showing an electric blower according to a second embodiment.

Fig. 7 is a plan view showing a diffuser of the electric blower according to the third embodiment.

Fig. 8 is a plan view showing a diffuser of the electric blower according to the fourth embodiment.

Fig. 9 is a plan view showing a comparative example for explaining the effect of the electric blower according to the fourth embodiment.

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

First Embodiment

<Configuration of Electric Vacuum Cleaner>

Fig. 1 is a schematic diagram of an electric vacuum cleaner according to an embodiment. In FIG. 1, the electric vacuum cleaner includes an electric vacuum cleaner body 1, a suction unit 4, a dust collection unit 5, an electric blower 6, and a discharge port 7. The suction part 4 is connected to the electric vacuum cleaner body 1 with a hose 2 and an extension pipe 3 as a pipeline, and sucks air in the part to be cleaned. The hose 2 is connected to the electric vacuum cleaner body 1. The extension tube 3 is connected to the front end side of the hose 2. The suction portion 4 is connected to a front end portion of the extension tube 3. The dust collection unit 5 is provided inside the electric vacuum cleaner body 1, communicates with the suction unit 4, and stores dust of the sucked air. The electric blower 6 is installed inside the electric cleaner body 1 and sucks air from the suction unit 4 to the dust collection unit 5. The electric fan 6 is an electric fan according to an embodiment of the present invention described later. The exhaust port 7 is provided outside the electric vacuum cleaner body 1 and discharges the air collected by the dust collection unit 5 to the outside of the electric vacuum cleaner body 1. The discharge port 7 is provided behind the electric cleaner body 1 as shown in FIG. 1.

A rear wheel 8 is arranged on the side of the electric cleaner body 1 on the rear side in the driving direction. A front wheel (not shown) is provided on the lower side of the electric cleaner body 1 on the front side in the driving direction.

<Composition of electric blower>

2 to 5, the electric blower 6 according to the first embodiment includes a centrifugal impeller 11, a motor 9, and a diffuser 15. The motor 9 includes a shaft 10. The centrifugal impeller 11 is fixed to the shaft 10. The motor 9 drives the centrifugal impeller 11 by rotating the shaft 10. The motor 9 is, for example, a motor such as a motor. The centrifugal impeller 11 and the diffuser 15 are housed in the fan cover 16 and are formed in an air passage between the fan cover 16 and the fan cover 16. In addition, in Figures 2 and 4, arrows Represents the flow of air.

The diffuser 15 is an air passage formed between the diffuser 15 and the fan cover 16 in a cross-sectional area (hereinafter simply referred to as a flow passage area) that is perpendicular to the direction of air flow. The diffuser 15 includes a plurality of stationary vanes 12, a plurality of returning stationary vanes 13, and a main plate 14. The main plate 14 is provided between the centrifugal impeller 11 and the motor 9 in a direction (hereinafter, referred to simply as a rotation axis direction) along the rotation axis O of the centrifugal impeller 11. The main plate 14 includes a connection portion 14A 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 motor 9 in the rotation axis direction. The connecting portion 14A includes an outer edge portion 14o located on the outer peripheral side of the main plate 14. In a plan view from the rotation axis direction, the planar shape of the main board 14 is substantially polygonal. The main board 14 has a relatively long portion and a short portion with a distance from the rotation axis O to the outer edge portion 14o. The main plate 14 is formed such that a relatively long portion and a short portion have a relatively long distance from the rotating shaft O to the outer edge portion 14 o in the rotating shaft direction of the centrifugal impeller 11. The planar shape of the main plate 14 is, for example, provided such that a relatively long distance from the rotation axis O to the outer edge portion 14o constitutes 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 relatively short Part of the internal angle is a vertex exceeding 180 degrees. In addition, the planar shape of the main plate 14 may be provided such that only a portion having a relatively long distance from the rotation axis O to the outer edge portion 14o constitutes an apex.

The plurality of stationary blades 12 are provided annularly on a surface of the connection portion 14A of the main plate 14 facing the centrifugal impeller 11. That is, the plurality of stationary blades 12 are arranged on the outer peripheral side than 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 peripheral portion) located on the outer peripheral side of the counter shaft O on the connecting portion 14A of the main plate 14. That is, outside the center of the rotation axis O The diameter D1 of the circle C1 connected to each of the second portions 12B of the plurality of stationary blades 12 is larger than the maximum value of the outer diameter of the main plate 14. Each of the plurality of stationary blades 12 has a first portion 12A having an inner edge portion 12i on the inner peripheral side, and a second portion 12B having an outer edge portion 12o on the outer peripheral side.

Each of the second portions 12B of the plurality of stationary blades 12 has an extension portion 23 extending in the direction of the rotation axis toward the motor 9 than the connection portion 14A of the main plate 14. That is, the second portion 12B has a portion having a longer length in the rotation axis direction than the first portion 12A.

Referring to FIG. 2, FIG. 3, and FIG. 5, the diameter D0 of the circle C0 inscribed on the outer edge portion 14 o of the main plate 14 is related to the circle C1 of the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12. The ratio D0 / D1 of the diameter D1 exceeds 0.9 (D0 / D1> 0.9). Further, the circle C0 inscribed on the outer edge portion 14o of the main plate 14 with the rotation axis O as the center is inscribed in a portion where the distance from the rotation axis O to the outer edge portion 14o on the main plate 14 is relatively short.

The plurality of returning stationary blades 13 are provided annularly on a surface on the motor 9 side of the main plate 14 in the rotation axis direction. The outer edge portion 13 o on the outermost peripheral side of the plurality of returning stationary blades 13 is, for example, located on the inner peripheral side than the outer edge portion 14 o of the main plate 14.

On the upper part of the centrifugal impeller 11 is provided a fan cover 16 with a built-in centrifugal impeller 11 and a stationary blade 12 of the diffuser 15. In the central portion of the fan cover 16, an opening portion and a bell mouth 18 are provided at a position of the centrifugal impeller 11 facing the suction port 17. The inner peripheral surface of the fan cover 16 is provided in a circular shape in a cross section perpendicular to the rotation axis direction.

On the side of the electric blower 6 is provided: connected to the fan cover 16 A bracket 19 for returning the stationary vane 13 and a motor frame 20 connected to the bracket 19 and having a motor 9 built therein are built in.

A gap 21 is provided between the fan cover 16 and the diffuser 15 on the outer peripheral side of the stationary blade 12 to form a gas flow path from the stationary blade 12 to the side of the stationary blade 13. A plurality of exhaust holes 22 are provided in the motor frame 20 to exhaust the air that has passed through the centrifugal impeller 11, the diffuser 15, and the motor 9.

<Operation of electric blower>

The electric blower 6 is configured to supply electric power to the motor 9, and the centrifugal impeller 11 mounted on the shaft 10 rotates to suck air from the suction port 17 into the bell port 18. The air sucked into the bell mouth 18 by the centrifugal impeller 11 is boosted and accelerated by the centrifugal impeller 11 and rotates while flowing into the counter-rotating shaft O. The blades of the plurality of stationary blades 12 located on the outer peripheral side of the centrifugal impeller 11 between. Then, the air system is pressurized and decelerated between the blades of the plurality of stationary blades 12. Further, the air is guided to the motor 9 side through the gap 21 between the diffuser 15 and the fan cover 16 by the return static vane 13 to cool the motor 9. Then, the 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 a second portion 12B (outer peripheral portion) located on the outer peripheral side with respect to the rotation axis O than the connecting portion 14A of the main plate 14 because the stationary blade 12 is compared with the conventional electric blower which does not have the second portion 12B. , Can reduce the ventilation resistance through the air path between the plurality of static blades 12 and back and forth between the return static blades 13. Furthermore, each of the second portions 12B of the plurality of stationary blades 12 has an extension portion 23 that extends to the motor 9 side than the connection portion 14A of the main plate 14 in the direction of the rotation axis. Compared with the electric blower, it can prevent the local backflow between the stationary blades 12 and the returning stationary blades 13 by reducing the ventilation resistance through the air path between the multiple stationary blades 12 and back and forth between the returning stationary blades 13. .

Furthermore, the ratio D0 / D1 of the diameter D0 of the circle C0 of the electric blower 6 inscribed on the outer edge portion 14o of the main plate 14 to the diameter C of the circle C1 of the second portion 12B of the plurality of stationary blades 12 exceeds 0.9. FIG. 5 is a graph showing the relationship between the ratio D0 / D1 obtained by numerical analysis and the efficiency of the blower for the electric blower including the same configuration as the electric blower 6 except 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 series configured to have a ratio D0 / D1 exceeding 0.9 was confirmed to be more efficient than the electric blower configured to have a ratio D0 / D1 to 0.9 or less. This is considered to be for the following reasons.

The diameter D0 of the circle C0 inscribed on the outer edge portion 14o of the main plate 14 is relatively smaller than the diameter D1 of the circle C1 circumscribed on the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12, and is formed by passing through the plurality The area of the gap 21 on the air path between the blades 12 and back and forth between the returning stationary blades 13 on the plane perpendicular to the direction of the rotation axis becomes larger. Therefore, the influence of the area of the gap 21 on the ventilation resistance, power, and efficiency of the electric blower 6 becomes large. Specifically, as the area of the gap 21 becomes larger, the ventilation resistance passing through the air path between the plurality of stationary blades 12 and back and forth between the returning stationary blades 13 is reduced, and the efficiency is improved. However, in a case where the ratio D0 / D1 is 0.9 or less and the area of the gap 21 becomes a predetermined size or more, a part of the air flowing between the plurality of stationary blades 12 reaches the outer edge portion 12o of the stationary blade 12 It previously flowed from the gap 21 to the side of the returning static blades 13, so it was not possible to sufficiently ensure the The amount of boost, and the efficiency decreases. 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.

In contrast, since the electric blower 6 is configured to have a ratio D0 / D1 exceeding 0.9, most of the air flowing between the plurality of stationary blades 12 flows into the returning stationary blade 13 side from the gap 21 after reaching the second portion 12B. Therefore, in the electric blower 6, since the air passing between the first portion 12A and the second portion 12B of the plurality of static blades 12 flows into the space between the return static blades 13 from the gap 21, the ventilation resistance of the air path is reduced. And the amount of pressure increase between the stationary blades 12 is ensured. As a result, even when the electric blower 6 is reduced in diameter, the efficiency is high.

<Specific example of electric blower>

Next, a specific example of the electric blower 6 will be described with reference to FIGS. 2 to 4. The electric blower 6 may include the following configuration in addition to this configuration.

As shown in FIG. 2, the outer edge portion 14o of the connecting portion 14A of the main board 14 on the outermost peripheral side of the rotating shaft O is more than the portion of the connecting portion 14A on the innermost peripheral side of the rotating shaft O, ie, the connecting portion 14A and The portion 14i connected to the inner edge portion 12i of the blade 12 is located closer to the motor 9 side in the rotation axis direction. From a different point of view, the connecting portion 14A is inclined from the portion 14i toward the outer edge portion 14o with respect to the rotation axis O toward the motor 9 side in the rotation axis direction.

In this way, the width of the air path formed between the plurality of stationary blades 12 and the fan cover 16 can be gradually enlarged in the radial direction of the centrifugal impeller 11, and can also be gradually enlarged in the rotation axis direction. Therefore, the electric blower 6 constituted in this way can be formed between a plurality of stationary blades 12 and the fan cover 16 as compared with the electric blower 6 including a structure in which the width of the air path is gradually enlarged only in the radial direction. The larger the area of the width of the air path is, the higher the amount of pressure increase in the air path is, so it is highly efficient.

As shown in FIG. 2, the extension portion 23 may be configured between an end portion of the extension portion 23 located on the motor 9 side in the rotation axis direction and a portion (outer edge portion 14o) located at the connection portion 14A farthest from the rotation shaft O. The distance in the rotation axis direction becomes larger as it goes toward the outer peripheral side.

In this way, when the operating condition of the electric blower 6 is located on the relatively low air volume side, the air can be smoothly guided from between the stationary blades 12 to the returning stationary blades 13 to reduce the ventilation resistance. Therefore, the amount of electric power required for the operation of the electric blower 6 series is reduced, which is highly efficient.

<Operation and effect of electric vacuum cleaner>

Next, the operation of the electric vacuum cleaner will be described. When the electric vacuum cleaner configured as described above supplies power to the motor 9, the shaft 10 rotates. As the shaft 10 rotates, the centrifugal impeller 11 mounted on the shaft 10 rotates, and air is sucked in from the suction port 17. Thereby, the air to be cleaned is sucked into the electric cleaner body 1 via the hose 2, the extension pipe 3, and the suction part 4 connected to the electric cleaner body 1. The air sucked by the electric vacuum cleaner body 1 is collected in the dust collection unit 5. Then, the air discharged from the dust collecting part 5 passes through the bell mouth 18 of the electric blower 6 and is sucked in from the suction port 17 of the centrifugal impeller 11. The air sucked in by the centrifugal impeller 11 is boosted and increased in speed by the centrifugal impeller 11 and is rotated outward while being rotated. Most of the air discharged from the centrifugal impeller 11 is decelerated and boosted between the blades of the stationary blades 12 of the diffuser 15. Then, the air passes through the gap 21 between the diffuser 15 and the fan cover 16. Further, the air is guided to the motor 9 side by the return static blade 13 and cools the motor 9. The air system is then set from The discharge hole 22 of the motor frame 20 is discharged to the outside of the electric blower. Then, air is exhausted to the outside of the electric cleaner body 1 from a discharge port 7 provided in the electric cleaner body 1.

In the above-mentioned electric vacuum cleaner, since the electric blower 6 configured as described above is used, a small and highly efficient electric blower and electric vacuum cleaner can be obtained.

Second embodiment

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

The plurality of stationary blades 12 may not be connected to, for example, the main plate 14 and the lower edge portion 14u in the rotation axis direction. Each of the second portions 12B (outer peripheral portions) of the plurality of stationary blades 12 has an extension portion 23 extending toward the motor 9 in the rotation axis direction than the connection portion 14A connected to the plurality of stationary blades 12. The portion (inner edge portion) on the innermost peripheral side of the extension portion 23 is connected to, for example, a portion located between the lower edge portion 14 u of the main plate 14 and the bent portion 25. The portion (outer edge portion) on the outermost peripheral side of the extension portion 23 is located closer to the motor 9 side in the rotation axis direction than the inner edge portion of the extension portion 23 and is closer to the motor in the rotation axis direction than the lower edge portion 14u of the main plate 14 9 sides are better.

The plurality of return static blades 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 way, because the electric blower 60 series basically includes Since the configuration is the same as that of the electric blower 6, the same effects as those of the electric blower 6 can be obtained. Furthermore, the electric blower 60 is a main plate 14 in which the connecting portion 14A of the main plate 14 has a bent portion 25 that is bent toward the side opposite to the centrifugal impeller 11, and therefore the main plate 14 The 14 series has high strength, and shows strong strength against distortion such as distortion.

Third Embodiment

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

In this manner, the interval between the outer edge portion 14o of the main board 14 and the inner peripheral surface of the fan cover 16 can be made constant in the rotation axis direction. Therefore, the planar shape of each gap 21 formed between the fan cover 16 and the diffuser 15 is uniformized in a plan view from the rotation axis direction. As a result, the electric blower according to the third embodiment is more efficient because the ventilation resistance is smaller than that of the electric blower 6.

Fourth Embodiment

Next, an electric blower according to a fourth embodiment will be described with reference to Fig. 8. The electric blower of the fourth embodiment basically includes the same configuration as the electric blower 6 of the first embodiment, but the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12 is in contact with the inner peripheral surface of the fan cover 16 Different. In addition, in Fig. 8, arrows indicate the flow of air.

Here, in a state where the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12 is in contact with the inner peripheral surface of the fan cover 16, the second portion 12B and the fan cover are shown. 16 is in a state of contact, or a state in which the second portion 12B and the fan cover 16 are arranged with a slight gap (for example, an interval of 1 mm or less). From a different point of view, the diameter D1 of the circle C1 circumscribing the second portion 12B (outer peripheral portion) of the plurality of stationary blades 12 with the rotation axis O as the center is connected to the inside of the fan cover 16 with the rotation axis O as the center. The diameter D2 of the circumferential circle C2 is substantially equal.

FIG. 9 is a plan view showing a diffuser 15 of the electric blower as a comparative example of the electric blower according to the fourth embodiment, including the second portion 12B of the plurality of stationary blades 12 without contacting the inner peripheral surface of the fan cover 16. In addition, in Fig. 9, arrows indicate the flow of air.

As shown in FIG. 9, when the second portion 12B of the plurality of stationary blades 12 is not in contact with the inner peripheral surface of the fan cover 16, the second portion 12B of the plurality of stationary blades 12 and the inner peripheral surface of the fan cover 16 A gap 24 is formed between them. In this case, in addition to the air path Q1 flowing from the stationary blades 12 through the gap 21 to the returning stationary blades 13, a plurality of stationary blades 12 are also formed to flow through the gaps 24 to the stationary blades 12 passing by first. Wind path Q2 between adjacent stationary blades 12. The air passing through the air passage Q2 merges with the air passing through the air passage Q1 and mixes with it. When the air that has passed through the air passage Q1 between the stationary blades 12 and the air that has passed through the air passage Q2 are mixed, the pressure increase between the stationary blades 12 is hindered, and the power may be reduced.

In contrast, if the electric blower according to the fourth embodiment has no gap 24 formed between the second portion 12B of the plurality of stationary blades 12 and the inner peripheral surface of the fan cover 16, it flows between the plurality of stationary blades 12. The air system does not mix with the air flowing between the adjacent stationary blades 12, but flows into the returning stationary blades 13 after passing through the gap 21. As a result, according to the fourth embodiment, The electric blower promotes the pressure increase between the stationary blades 12 and the power becomes higher, so the efficiency is high.

The electric blowers according to the first to fourth embodiments are as described above, and can be mounted on the cylindrical electric vacuum cleaner body 1 connected to the hose 2 and the extension pipe 3 as shown in FIG. 1, but it is not limited to this. . The electric blower according to the first to fourth embodiments may be an electric cleaner body that is mounted on other types of electric cleaners such as a cordless type or a rod type electric cleaner that connects the extension tube to the electric cleaner body.

The electric blower according to the first to fourth embodiments described above is configured as an electric blower including a centrifugal impeller 11 using a two-dimensional blade, but the form of the centrifugal impeller 11 is not particularly limited, and for example, it may be configured to include a three-dimensional Electric fan of centrifugal impeller of blade.

In addition, the electric blowers according to the first to fourth embodiments are not limited to electric vacuum cleaners for home use or business use, and can be applied to any equipment using electric blowers such as hand dryers. As a result, a high-efficiency and long-life machine can be realized.

As mentioned above, although embodiment of this invention was described, various deformation | transformation of the said embodiment is possible. The scope of the present invention is not limited to the embodiments described above. The scope of the present invention is intended to include all modifications within the meaning and scope equivalent to the scope of the patent application, as indicated by the scope of the patent application.

[Industrial applicability]

The present invention is particularly advantageously used in appliances using electric blowers such as electric vacuum cleaners and hand dryers for home and business use.

Claims (7)

An electric blower includes: a centrifugal impeller; a motor that rotates the centrifugal impeller; and a diffuser, which is arranged between the centrifugal impeller and the motor in a direction along the rotation axis of the centrifugal impeller; the diffuser includes: The main plate is disposed between the centrifugal impeller and the motor in the direction; a plurality of stationary blades are annularly disposed on a surface of the main plate facing the centrifugal impeller in the direction; and a plurality of return static blades, It is arranged on the side of the main board facing the motor in a ring shape in the direction. The main board has a connecting portion which is located on the outer peripheral side of the rotating shaft than the centrifugal impeller and is connected to the plurality of stationary blades. ; Each of the outer peripheral portions of the plurality of stationary blades has an extension extending in the direction toward the motor side than the connecting portion of the main board; the diameter D0 of the circle inscribed on the outer edge portion of the main board is external The ratio D0 / D1 of the diameter D1 of the circle at the outer periphery of the plurality of stationary blades exceeds 0.9. For example, the electric blower according to item 1 of the patent application, wherein a portion of the connecting portion located farthest from the rotating shaft is located closer to the motor side in the direction than a portion of the connecting portion located closest to the rotating shaft. For example, if the electric blower of item 1 or 2 of the patent application scope, the extension is configured between an end of the extension located on the motor side in the direction and a portion of the connection located farthest from the shaft. The distance in this direction becomes larger as it goes toward the outer peripheral side. For example, the electric blower of item 1 or 2 of the patent application scope, wherein the planar shape of the main board is circular. For example, the electric blower according to item 1 or 2 of the patent application scope, wherein the connecting portion has a bent portion bent in the direction toward the motor side. For example, the electric blower for item 1 or 2 of the patent application scope further includes a fan cover that houses the centrifugal impeller and the diffuser inside; the outer peripheral portion of the plurality of stationary blades is in contact with the inner peripheral surface of the fan cover . An electric vacuum cleaner includes: an electric vacuum cleaner body; a suction part connected to the electric vacuum cleaner body by a pipe and sucking in the air of a part to be cleaned; a dust collecting part is provided inside the electric vacuum cleaner body and the suction The electric blower such as item 1 or 2 of the scope of the patent application is installed inside the electric vacuum cleaner body and sucks air from the suction part to the dust collection part.