JP2002138996A - Electric blower and vacuum cleaner provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric blower capable of efficiently recovering a dynamic pressure of air stream from a centrifugal impeller as a static pressure by a diffuser, reducing loss of a bent part from the diffuser to return, and improving air blow efficiency. SOLUTION: In this electric blower provided with the centrifugal impeller 12 and the diffuser 11 provided in an outer peripheral part of the centrifugal impeller 12 and having a plurality of diffuser vanes 11a, an intermediate vane 11b having a smaller dimension in the direction of height than a dimension in the direction of height of the diffuser vane 11a is provided in the vicinity of an outlet of an air flow passage formed between the diffuser vanes 11a of the diffuser 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal impeller and an electric blower having a centrifugal diffuser, and more particularly to an electric blower for a vacuum cleaner suitable for increasing the efficiency and output of the vacuum cleaner. is there.

[0002]

2. Description of the Related Art The shape of a diffuser of an electric blower is disclosed in Japanese Patent Application Laid-Open No. 10-71108.

[0003] The structure disclosed in Japanese Patent Application Laid-Open No. 10-71108 has small vanes between adjacent diffuser vanes, and the small vanes have an upstream end portion formed between adjacent diffuser vanes. The diffuser vanes on both sides of the road are located downstream of half of the overlapping portion.

According to the prior art described above, the influence of the drift generated between the diffuser vanes can be reduced, so that the air flow speed can be made uniform and the loss can be reduced. In addition, since the resonance frequency at the overlapping portion of the diffuser vane can be shifted to a high frequency by the small vane,
The frequency at which the blade sound is amplified can be shifted to a frequency that is difficult to hear. However, there is no particular description on the reduction of the bending loss from the diffuser side to the return side, which is a large loss in an electric blower.

[0005]

In recent years, electric blowers are provided with a diffuser having a diffuser vane or are rotated at a high speed to achieve a small size and high efficiency. However, when the size is reduced, there is a problem that the bent portion from the diffuser side to the return side becomes narrower, and the loss of the air flow at the bent portion increases.

In the diffuser having the diffuser vanes, the maximum efficiency of the electric blower is improved. However, when the air flow is lower than the air flow at which the maximum efficiency point is obtained, the blower efficiency is reduced due to separation at the diffuser and development of the boundary layer. It is a problem.

[0007] Further, in the vacuum cleaner, the improvement in efficiency on the low air flow side leads to maintaining the suction force even when dust accumulates in the dust collection bag.

SUMMARY OF THE INVENTION It is an object of the present invention to efficiently recover a dynamic air pressure from a centrifugal impeller as a static pressure by a diffuser, to reduce a loss of a bent portion from a diffuser side to a return side, and to improve air blowing efficiency. An object of the present invention is to provide an electric blower and a vacuum cleaner having the same.

It is another object of the present invention to provide an electric blower which improves the blowing efficiency in a wide flow range from a low air flow to a high air flow, and a vacuum cleaner having the same.

[0010]

Means for Solving the Problems In order to achieve the above object, the features of the electric blower of the present invention are as follows.
An intermediate blade having a height dimension smaller than the height dimension of the diffuser vane is provided near an air flow path outlet formed between the diffuser vanes provided on the outer peripheral portion of the centrifugal impeller.

Specifically, the present invention provides the following blowers and vacuum cleaners.

The present invention relates to an electric blower having a centrifugal impeller and a diffuser provided on an outer peripheral portion of the centrifugal impeller and having a plurality of diffuser vanes, wherein an air flow path outlet formed between the diffuser vanes is provided. In the vicinity,
An electric blower is provided, wherein an intermediate blade having a height dimension smaller than the height dimension of the diffuser vane is provided.

The present invention also includes a centrifugal impeller, and a diffuser provided on the outer peripheral portion of the centrifugal impeller, the diffuser having a plurality of diffuser vanes on the front side and a return guide vane on the back side. In the electric blower, an intermediate blade having a height dimension smaller than the height dimension of the diffuser vane is provided on the diffuser vane side and near an air flow path outlet formed between the respective diffuser vanes. An electric blower characterized by the following.

[0014] Preferably, the width of the flow path between the blades of the overlapping portion formed by the intermediate blade and the diffuser vanes on both sides thereof increases from the upstream side to the downstream side, and a negative pressure surface of the flow path between the blades. The width of the flow path between the side blades is larger than the width of the flow path between the pressure surface side blades.

Further, according to the present invention, there is provided a dust collecting chamber joined to a suction port for sucking dust on a surface to be cleaned, and an electric motor arranged behind the dust collecting chamber to form an air flow for sucking the dust from the suction port. In a vacuum cleaner having a blower, the electric blower is the electric blower according to any one of claims 1 to 3, and further provides a vacuum cleaner.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an electric blower according to an embodiment of the present invention and a vacuum cleaner having the same will be described with reference to the drawings.

FIG. 10 is an external perspective view of a vacuum cleaner provided with an electric blower according to an embodiment of the present invention.

The present vacuum cleaner is connected via an extension tube 205 to a hose handle 204 provided at the end of a hose 203 rotatably connected to a vacuum cleaner main body 201 having a built-in electric blower and a dust collecting filter. A suction port 206 is attached. Further, the hose hand section 204 is provided with a switch operation section 207 for controlling the electric blower in the vacuum cleaner main body 201.

FIG. 11 shows the vacuum cleaner main body 201 of FIG.
FIG. The outer casing of the vacuum cleaner main body 201 is constituted by a lower case 301, an upper case 302, and a dust collecting cover 303. A suction port 304 is formed in the dust collection lid 303, and inside the dust collection bag 3, the dust collection bag 3 is connected to the suction port 304.
A dust collection chamber 306 that accommodates the dust collection chamber 05 is formed. An electric blower chamber 307 follows the dust collection chamber 306, and an electric blower 308 is accommodated therein.

FIG. 9 is a longitudinal sectional view of the electric blower 308 housed in the electric vacuum cleaner main body 201 of FIG.

The electric blower 308 includes the blower 1 and the electric motor 2
They are roughly divided into The blower 1 includes a centrifugal impeller 12, a diffuser 11 provided on an outer peripheral portion of the centrifugal impeller 12,
It comprises a centrifugal impeller 12 and a fan casing 13 containing the diffuser 11.

The stationary flow path section 10 is provided with a diffuser 11 having a plurality of diffuser vanes 11a on the front side and a partition plate 10a having a return guide vane 14 on the back side.

The electric motor 2 comprises a case comprising a housing 3 and an end bracket 9, a rotor 5 having a rotating shaft 4 housed in the case, and a stator 7 opposed to the rotor 5 and having a stator coil 6 wound thereon. It is composed of

Next, the flow of air in the electric blower 308 will be described with reference to FIG.

When the motor 2 is driven to rotate the centrifugal impeller 12, an air flow 101 flows into the centrifugal impeller 12 from the suction port 13b. At this time, the airflow guide 13a rectifies the airflow flowing into the centrifugal impeller 12.

The air flow 10 discharged from the centrifugal impeller 12
2 passes between the diffuser vanes 11 a of the diffuser 11, and the passed air flow 103
At a circular gap (hereinafter referred to as a bend) between the outer circumference of the fan casing 13 and the inner circumference of the fan casing 13,
Further, after passing between the blades of the return guide vane 14, it is introduced into the electric motor 2.

At this time, the air flow 104 introduced into the electric motor 2 passes through the air flow path formed in the housing 3 to cool the rotor 5, the stator coil 6, the brush 15 and the like, and then to the outside through the exhaust port 3c. Is discharged to

In the electric blower 308 as described above,
In order to improve the blowing efficiency, the diffuser 11 decelerates the airflow 102 discharged from the centrifugal impeller 12 while preventing loss as much as possible, and converts dynamic pressure into static pressure (hereinafter referred to as pressure recovery). It is important to reduce the loss of the airflow 103 at the bend from the diffuser 11 to the return guide vane 14.

In the electric blower 308, the diffuser 11
Air flow 103 passing between the diffuser vanes 11a
Turns 180 degrees at the bend, and further passes between the vanes of the return guide vane 14. For this reason, the air flow 103 flows in the diffuser height direction on the outlet side of the diffuser 11 in the diffuser height direction.
Since the radius of curvature of the bend is small on the upper surface side, reverse flow and separation of the air flow occur, making it difficult to recover the pressure, and the loss of the air flow 103 is large. If the flow rate is lower than the flow rate at which the highest efficiency point is obtained, the air blowing efficiency decreases due to peeling, which leads to an unstable phenomenon.

Next, details of the electric blower according to one embodiment of the present invention will be described with reference to FIGS.

FIG. 1 is a plan view of a diffuser of an electric blower according to an embodiment of the present invention, and is a plan view of a diffuser provided in the electric blower of FIG. FIG.
FIG. 3 is a cross-sectional view taken along a line AB of the diffuser of FIG.
FIG. 2 is an enlarged view of a portion C of the diffuser of FIG. 1. FIG. 4 is a view showing the flow in the bent pipe, and FIG. 5 is a sectional view taken along the line D-E of FIG.

First, the flow in a general curved pipe will be described with reference to FIGS.

As shown in FIG. 4, the flow in the bent pipe 401 is deviated from the inner wall 402 to the outer wall 403. Further, the flow has a backflow region near the inner wall 402, and when the backflow region develops, the flow causes separation near the inner wall 402. In the section D-E,
Since a larger centrifugal force acts on the outer diameter side of the bend than on the inner diameter side of the bend, a secondary flow as shown in FIG. 5 is generated.

As described above, generally, in a curved pipe, the flow is biased from the inner diameter side of the bend to the outer side, and a secondary flow is generated. In addition, if the curvature of the bend is small, the flow will separate from the inner diameter wall.

As shown in FIGS. 1 and 2, the diffuser 11 has a plurality of diffuser vanes 11a formed on the upper side (front side) of a partition plate 10a.
The intermediate blade 11b having a height dimension smaller than the height dimension of the diffuser vane 11a is provided in the vicinity of the air flow path outlet formed therebetween.

As shown in FIGS. 2 and 3, the distance between the blades at the outlet of the overlapping portion of the adjacent diffuser vanes 11a is the sum of W2 and W3 on the upper surface of the partition plate 10a, and the overlapping between the diffuser vanes 11a is obtained. The distance between the blades W1 at the tip of the diffuser vane 11a at the outlet is smaller by the provision of the intermediate blade 11b.

For this reason, the partition plate 10 of the diffuser 11
The air flow velocity is higher at the upper surface portion of a than at the front end portion of the diffuser vane 11a in the height direction. For this reason, the pressure increases in the height direction of the diffuser vane 11a at the outlet of the flow channel of the diffuser 11, the tip of the diffuser vane 11a is high, and the upper surface of the partition plate 10a, that is, the root of the diffuser vane 11a is low. Occurs.

Here, a comparison of the flow of air at the bend from the diffuser 11 to the return guide vane 14 depending on the presence or absence of the intermediate blade 11b will be described with reference to FIGS. FIG. 6 shows the air flow when the intermediate blade 11b is provided, and FIG. 7 shows the air flow when the intermediate blade 11b is not provided.

As shown in FIG. 6, near the outlet flow path of the diffuser 11, as described above, a pressure difference occurs in which the front end portion of the diffuser vane 11a in the height direction is high and the root portion of the diffuser vane 11a is low. Therefore, the air flow 106 on the outer diameter side of the bend and the air flow 10 on the inner diameter side of the bend
In 5, a force acts from the outer diameter side to the inner diameter side of the bend.

Therefore, the air flow 106 on the outer diameter side of the bend and the air flow 105 on the inner diameter side of the bend can be smoothly turned from the diffuser 11 side to the return guide vane 14 side.

Further, since a force acts from the outer diameter side to the inner diameter side of the bend, the secondary flow due to the difference in the centrifugal force at the bend is suppressed, and the loss can be reduced.

Further, the air flow 105 on the inner diameter side of the bend is
Since it adheres and flows to the partition plate 10a side which is the inner diameter side of the bend, it also leads to suppression of the separation region 107 generated when there is no intermediate blade 11b shown in FIG. Can be improved.

The boundary layer developed on the pressure surface 11d side of the diffuser 11 is contracted by the flow of air at the inlet side of the intermediate blade 11b, so that the developed boundary layer is thinned.
Peeling can be suppressed and loss can be reduced.

In the vacuum cleaner, the sucked dust and air are separated by the dust collecting bag 305. If the dust is fine,
It may pass through the dust bag 305 and flow into the electric blower 308. The suppression of the separation in the diffuser 11 prevents the fine dust from adhering and accumulating in the diffuser 11 and has an effect of preventing the passage from being blocked.

Further, in the region where the intermediate blade 11b is present, as shown in FIGS. 2 and 3, the width of the inter-blade flow passage surrounded by the suction surface 11c of the diffuser vane 11a and the intermediate blade pressure surface 11f is increased. The case where the width is larger than the width of the flow path between the blades surrounded by the pressure surface 11d of the diffuser vane 11a and the intermediate blade negative pressure surface 11e will be described below.

In the electric blower for the vacuum cleaner, on the low flow rate side, the flow of air in the diffuser 11 depends on the suction surface 11c of the diffuser vane 11a on the upper surface of the partition plate 10a at the overlapping portion of the adjacent diffuser vanes 11a. And the flow velocity is fast. Conversely, diffuser vane 11
On the pressure surface 11d side of a, large-scale separation or backflow is likely to occur, and not only does the pressure recovery in the diffuser 11 decrease, but also instability occurs in the air flow in the electric blower.

The pressure surface 11d of the diffuser vane 11a
By reducing the flow of air on the upstream side of the intermediate blade 11b, the boundary layer developed on the side is prevented from developing the boundary layer and thinned, and the pressure surface 11d of the diffuser vane 11a and the intermediate blade suction surface 11e are reduced. By suppressing the deceleration of the flow path surrounded by {circle around (1)}, separation and backflow are suppressed.

Further, adjacent diffuser vanes 11
The air flow on the upper surface of the partition plate 10a is deviated and the flow velocity is high among the overlapped portions of the diffuser vanes 11a. The negative pressure surface 11c of the diffuser vanes 11a and the intermediate blade pressure surface 11f are surrounded by the diffuser vanes 11a. By increasing the flow path width, the speed can be effectively reduced and the pressure can be recovered.

Therefore, on the low air flow side, large-scale separation and backflow in the diffuser 11, which are causes of instability, are suppressed.
In addition, since the pressure recovery is performed by the diffuser 11, it is possible to prevent a decrease in the blowing efficiency. Further, the dust collecting bag 30 of the vacuum cleaner is used.
Even in the case of a low flow rate in which dust is accumulated in 5, a predetermined output of the electric blower can be obtained, and the suction power of the vacuum cleaner can be maintained.

In the overlapping portion of the diffuser vane 11a, the flow on the upper surface of the partition plate 10a is deviated and the flow speed is high, and the speed of the negative pressure surface 11c side of the diffuser vane 11a is reduced, and the pressure surface of the diffuser vane 11a is reduced. 1
By suppressing the deceleration of the flow path surrounded by 1d and the intermediate blade negative pressure surface 11e, the uneven flow is corrected and uniformized, thereby preventing the mixing loss due to the uneven flow velocity. it can.

As shown in FIG. 1, the diffuser 1
In the vicinity of the outlet of the first flow path, the partition plate 10a is cut out in a substantially triangular shape, and the flow area of the bent portion is increased, so that the air flow 103 is turned from the diffuser 11 to the return guide vane 14 side. It is possible to turn smoothly with a reduced loss without increasing the flow velocity.

FIG. 8 is a plan view of a diffuser according to another embodiment of the present invention.

The difference from the diffuser shown in FIG. 1 is that the downstream end of the intermediate blade 11b is not extended to a portion where the partition plate 10a is cut into a substantially triangular shape near the outlet of the diffuser 11 near the flow path. is there.

In the embodiment shown in FIG.
By rounding off the corners of the end of a in an R-shape to eliminate the corners, the air flow 103 at the bent portion is
At the time of turning from the 1a side to the return guide vane 14 side, peeling is prevented, and the turning can be performed smoothly. As a result, the efficiency of the electric blower is improved.

As shown in FIG. 3, the intermediate blade 11b
Is rounded at the upstream end of the intermediate blade 11b, so that separation can be suppressed when a flow hits the upstream end of the intermediate blade 11b. Therefore, an increase in loss due to peeling can be suppressed.

Although not shown in the figure, the intermediate blade 1
1b may be rounded at the tip in the height direction, or the intermediate blade 1
By providing a draft in the blade height direction of the intermediate blade 11b so as to reduce the blade thickness of the intermediate blade 11b, the intermediate blade 11
b becomes easier to mold. Even with the intermediate blade 11b molded in this way, the same effect as that of the present embodiment can be obtained.

In the embodiment of the present invention, as shown in FIG. 2, the intermediate blade 11b is
As in the case of 1a, the structure is formed integrally with the partition plate 10a, but the intermediate blade 11b may be formed of a separate member and fixedly arranged on the upper surface of the partition plate 10a.

Further, the diffuser vanes 11a and the intermediate blades 11b are provided on the upper surface of the partition plate 10a, the return guide vanes 14 are provided on the back surface of the partition plate 10a, and the partition plate 1a.
0a, and in this case, the diffuser 1
1 becomes easy to manufacture.

[0059]

According to the present invention, a pressure difference is generated in the diffuser vane height direction in the outlet flow passage portion of the diffuser where the diffuser vane tip is high and the diffuser vane root is low. A force is applied from the outer diameter side to the inner diameter side of the portion, and the air flow is smoothly turned to the return side. At this time, since a force from the outer diameter side to the inner diameter side of the bent portion acts, the secondary flow at the bent portion is suppressed, and the mixing loss caused by the uneven flow velocity can be reduced.

Further, since the secondary flow is suppressed, the separation on the inner diameter side of the bent portion can be suppressed, so that the efficiency of the electric blower can be improved.

In addition, since large-scale separation and backflow in the diffuser, which are causes of instability, are suppressed on the low air flow side and pressure recovery is performed by the diffuser, the blower can be blown over a wide flow range from low air flow to high air flow. It is possible to prevent a decrease in efficiency, and even in the case of a low flow rate in which dust is accumulated in the dust collection bag of the vacuum cleaner, the output of the predetermined electric blower can be obtained, and the suction power of the vacuum cleaner can be maintained. .

[Brief description of the drawings]

FIG. 1 is a plan view of a diffuser of an electric blower according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along a line AB of the diffuser of FIG.

FIG. 3 is an enlarged view of a portion C of the diffuser of FIG. 1;

FIG. 4 is a diagram of a flow in a bent pipe.

FIG. 5 is a sectional view taken along the line D-E of FIG. 4;

FIG. 6 is a diagram showing a flow of air when an intermediate blade is provided.

FIG. 7 is a diagram showing the flow of air when no intermediate blade is provided.

FIG. 8 is a plan view of a diffuser according to another embodiment of the present invention.

9 is a vertical sectional view of the electric blower housed in the vacuum cleaner main body of FIG.

FIG. 10 is an external perspective view of a vacuum cleaner provided with the electric blower according to the embodiment of the present invention.

FIG. 11 is a longitudinal sectional view of the vacuum cleaner main body of FIG. 10;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... blower, 2 ... electric motor, 3 ... housing, 3c ... exhaust port, 4 ... rotating shaft, 5 ... rotor, 6 ... stator coil, 7
... Stator, 9 ... End bracket, 10 ... Stationary flow path section, 10a ... Partition plate, 11 ... Diffuser, 11a ... Diffuser vane, 11b ... Intermediate blade, 11c ... Negative pressure surface, 11d ... Pressure surface, 11e ... Intermediate blade negative pressure surface , 11f
... Intermediate impeller pressure surface, 12... Centrifugal impeller, 13... Fan casing, 13a.
... Return guide vane, 15 ... Brush, 32 ... Power supply terminal, 101,102,103,104 ... Air flow, 201 ...
Vacuum cleaner body, 203 ... Hose, 205 ... Extension tube, 2
06 ... suction port, 301 ... lower case, 302 ... upper case, 3
06 ... dust collection room, 307 ... electric blower room, 308 ... electric blower

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Fumio Joraku 1-1-1, Higashitagacho, Hitachi City, Ibaraki Prefecture Inside Hitachi Taga Electronics Co., Ltd. (72) Inventor Hideyuki Harada 1-1-1, Higashitagacho, Hitachi City, Ibaraki Prefecture No. 1 Inside Hitachi Taga Electronics Co., Ltd. (72) Inventor Kazuyuki Sugimura 502 Kandate-cho, Tsuchiura-shi, Ibaraki F-term in Mechanical Engineering Laboratory, Hitachi, Ltd. (Reference) 3B006 FA02 3H034 AA02 AA13 BB02 BB06 BB20 CC03 DD07 DD22 EE05 EE18

Claims (4)

[Claims] An electric blower comprising: a centrifugal impeller; and a diffuser provided on an outer peripheral portion of the centrifugal impeller and having a plurality of diffuser vanes. And an intermediate blade having a height dimension smaller than a height dimension of the diffuser vane. 2. An electric blower comprising a centrifugal impeller and a diffuser provided on an outer peripheral portion of the centrifugal impeller, the diffuser having a plurality of diffuser vanes on a front side and a return plate vane on a back side. An intermediate blade having a height dimension smaller than the height dimension of the diffuser vane is provided on the diffuser vane side and in the vicinity of an air flow path outlet formed between the respective diffuser vanes. Electric blower. 3. The inter-blade passage width of the overlapping portion formed by the intermediate blade and the diffuser vanes on both sides thereof increases from the upstream side to the downstream side according to claim 1 or 2, and An electric blower characterized in that the width of the suction-side inter-blade flow path in the inter-blade flow path is larger than the expansion of the pressure-surface side inter-blade flow path width. 4. A dust collecting chamber joined to a suction port for sucking dust on a surface to be cleaned, and an electric blower arranged behind the dust collecting chamber to form an air flow for sucking the dust from the suction port. An electric vacuum cleaner, wherein the electric blower is the electric blower according to any one of claims 1 to 3.