JP3801855B2 - Electric blower and vacuum cleaner provided with the same - Google Patents

Description

[0001]
BACKGROUND 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 a vacuum cleaner.
[0002]
[Prior art]
Some diffuser shapes of electric blowers are disclosed in JP-A-10-71108.
[0003]
The structure disclosed in Japanese Patent Application Laid-Open No. 10-71108 includes a small vane between adjacent diffuser vanes, and the small vanes are arranged on both sides of the inter-blade channel formed by the adjacent diffuser vanes at the upstream end. It arrange | positions downstream from the half of the overlap part of a diffuser vane.
[0004]
According to the conventional technique as described above, since the influence of the drift generated between the diffuser vanes can be reduced, the speed of the air flow can be made uniform and the loss can be reduced. In addition, since the resonance frequency at the overlapping portion of the diffuser vanes can be shifted to a higher frequency by the small vanes, the frequency at which the blade sound is amplified can be shifted to a frequency that is difficult to be heard. However, there is no particular description about reducing the bending loss from the diffuser side to the return side, which has a large loss in the electric blower.
[0005]
[Problems to be solved by the invention]
In recent years, an electric blower is provided with a diffuser having a diffuser vane or is rotated at a high speed to achieve a small size and high efficiency. However, when the size is reduced, the bent portion from the diffuser side to the return side becomes narrow, and there is a problem that the loss of air flow at the bent portion increases.
[0006]
In addition, in a diffuser with a diffuser vane, the maximum efficiency of the electric blower is improved. ing.
[0007]
Further, in the vacuum cleaner, the improvement in efficiency on the low air volume side leads to maintaining the suction force even when dust accumulates in the dust collection bag.
[0008]
An object of the present invention is to recover an air flow from a centrifugal impeller efficiently with a diffuser as a dynamic pressure, to reduce a loss of a bent portion from the diffuser side to a return side, and to improve an air blowing efficiency and It is in providing the vacuum cleaner provided with it.
[0009]
It is another object of the present invention to provide an electric blower that improves the blowing efficiency in a wide flow rate range from a low air volume to a high air volume, and a vacuum cleaner including the same.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, the electric blower according to the present invention is characterized by changing the direction of the air flow that has passed between the diffuser vanes at a gap formed between the inner periphery of the fan casing and the outer periphery of the diffuser. After that, the flow path is configured to pass between the return guide vanes, and in the vicinity of the air flow path outlet formed between the diffuser vanes, the height direction is smaller than the height direction dimension of the diffuser vane extending from the partition plate An intermediate blade having a size is provided, and the sum of the distance between the blades of the intermediate blade and each diffuser vane is made smaller than the distance between the blades at the tip of each diffuser vane.
[0011]
Specifically, the present invention provides the following blower and vacuum cleaner.
[0013]
The present invention provides a centrifugal impeller, a diffuser provided on an outer peripheral portion of the centrifugal impeller, and provided with a partition plate having a plurality of diffuser vanes on the front side and a return guide vane on the back side, the centrifugal impeller, and the In the electric blower including a fan casing containing the diffuser, a gap is formed between the inner periphery of the fan casing and the outer periphery of the diffuser, and the air flow that has passed between the diffuser vanes is changed in direction in the gap. The diffuser vane extending from the partition plate is configured so as to pass between the return guide vanes and on the diffuser vane side and in the vicinity of an air flow path outlet formed between the diffuser vanes. An intermediate vane having a height direction dimension smaller than the height direction dimension of the intermediate vane and each of the diffs The sum of the inter-blade distance between Zaben is to provide an electric blower, characterized in that said set smaller than the inter-blade distance of each diffuser vane tip.
[0014]
Preferably, the inter-blade channel width of the overlapping portion constituted by the intermediate vane and the diffuser vanes on both sides thereof widens from the upstream side to the downstream side, and the suction surface side inter-blade flow in the inter-blade channel The expansion of the passage width is larger than the expansion of the passage width between the pressure side blades.
[0015]
Further, the present invention includes a dust collection chamber joined to a suction port for sucking dust on a surface to be cleaned, and an electric blower that is arranged behind the dust collection chamber and forms an air flow for sucking the dust from the suction port. In the vacuum cleaner which has, the said electric blower is an electric blower of Claim 1 or Claim 2 , It provides the vacuum cleaner characterized by the above-mentioned.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an electric blower according to an embodiment of the present invention and a vacuum cleaner including the same will be described with reference to the drawings.
[0017]
FIG. 10 is an external perspective view of a vacuum cleaner provided with an electric blower according to an embodiment of the present invention.
[0018]
In the present vacuum cleaner, a suction port 206 is connected to a hose proximal portion 204 provided at the tip of a hose 203 rotatably connected to a vacuum cleaner main body 201 containing an electric blower and a dust collecting filter via an extension pipe 205. It is attached. Further, the hose handle portion 204 is provided with a switch operation portion 207 for controlling the electric blower in the electric vacuum cleaner main body 201.
[0019]
FIG. 11 is a longitudinal sectional view of the electric vacuum cleaner main body 201 of FIG. The vacuum cleaner main body 201 is configured by an outer case 301, an upper case 302, and a dust collecting lid 303. A suction port 304 is formed in the dust collection lid 303, and a dust collection chamber 306 that houses a dust collection bag 305 joined to the suction port 304 is formed inside the dust collection lid 303. An electric blower chamber 307 follows behind the dust collection chamber 306, and an electric blower 308 is accommodated.
[0020]
FIG. 9 is a longitudinal sectional view of the electric blower 308 housed in the electric vacuum cleaner main body 201 of FIG.
[0021]
The electric blower 308 is roughly classified into the blower 1 and the electric motor 2. The blower 1 includes a centrifugal impeller 12, a diffuser 11 provided on the outer periphery of the centrifugal impeller 12, and a fan casing 13 that encloses the centrifugal impeller 12 and the diffuser 11.
[0022]
The stationary flow path unit 10 includes 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.
[0023]
The electric motor 2 includes a case composed of a housing 3 and an end bracket 9, a rotor 5 having a rotating shaft 4 housed in the case, and a stator 7 on which a stator coil 6 is wound so as to face the rotor 5. Has been.
[0024]
Next, the flow of air in the electric blower 308 will be described with reference to FIG.
[0025]
When the electric motor 2 is driven and the centrifugal impeller 12 is rotated, the air flow 101 flows into the centrifugal impeller 12 from the suction port 13b. At this time, the airflow guide 13 a rectifies the airflow flowing into the centrifugal impeller 12.
[0026]
The air flow 102 discharged from the centrifugal impeller 12 passes between the diffuser vanes 11 a of the diffuser 11, and the passed air flow 103 is an annular shape between the outer periphery of the stationary flow path portion 10 and the inner periphery of the fan casing 13. In the gap portion (hereinafter referred to as a bent portion), the direction is changed by 180 degrees, and after passing between the blades of the return guide vane 14, it is introduced into the electric motor 2.
[0027]
At this time, the air flow 104 introduced into the electric motor 2 passes through an air flow path formed in the housing 3, cools the rotor 5, the stator coil 6, the brush 15, and the like and is discharged to the outside from the exhaust port 3 c. The
[0028]
In the electric blower 308 as described above, in order to improve the air blowing efficiency, the air flow 102 discharged from the centrifugal impeller 12 is decelerated by the diffuser 11 while preventing loss as much as possible, and the dynamic pressure is made static. It is important to convert (hereinafter referred to as pressure recovery) and to reduce the loss of the air flow 103 at the bend from the diffuser 11 to the return guide vane 14.
[0029]
In the electric blower 308, the air flow 103 that has passed between the diffuser vanes 11 a of the diffuser 11 changes direction by 180 degrees at the bent portion, and further passes between the blades of the return guide vane 14. For this reason, the air flow 103 recovers pressure by causing a reverse flow or separation of the air flow, because the curvature radius of the bending is small on the upper surface side of the partition plate 10a of the diffuser 11 in the diffuser height direction on the outlet side of the diffuser 11. It is difficult and the loss of the air flow 103 is large. In addition, when the flow rate is lower than the flow rate at which the highest efficiency point is obtained, the air blowing efficiency is reduced due to peeling, leading to an unstable phenomenon.
[0030]
Next, details of the electric blower according to the embodiment of the present invention will be described with reference to FIGS.
[0031]
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. 2 is a cross-sectional view taken along the line AB of the diffuser of FIG. 1, and FIG. 3 is an enlarged view of a C portion of the diffuser of FIG. 4 is a flow diagram in the bent pipe, and FIG. 5 is a sectional view taken along the line D-E in FIG.
[0032]
First, the flow in a general bent pipe will be described with reference to FIGS.
[0033]
As shown in FIG. 4, the flow in the bent tube 401 is biased from the inner wall 402 side of the bent toward the outer wall 403 side. In addition, a reverse flow region is generated in the vicinity of the inner diameter side wall 402, and when this reverse flow region is developed, the flow is separated near the inner diameter side wall 402. Moreover, in the DE cross section, since a centrifugal force larger than the inner diameter side of the curve acts on the outer diameter side of the curve, a secondary flow as shown in FIG. 5 occurs.
[0034]
As described above, generally, in the bent pipe, the flow is biased from the inner diameter side to the outer shape side, and a secondary flow is generated. Furthermore, when the curvature of bending is small, the flow causes separation from the inner wall.
[0035]
As shown in FIGS. 1 and 2, the diffuser 11 is formed with a plurality of diffuser vanes 11a on the upper side (front side) of the partition plate 10a, and in the vicinity of the air flow path outlet formed between the diffuser vanes 11a. The intermediate blade 11b having a height direction dimension smaller than the height direction dimension of the vane 11a is provided.
[0036]
Further, as shown in FIGS. 2 and 3, the distance between the blades at the overlapping portion outlet of the adjacent diffuser vane 11a is the sum of W2 and W3 on the upper surface of the partition plate 10a, and the overlapping portion outlet between the diffuser vanes 11a is the sum of the distances. Compared to the distance W1 between the blades at the tip of the diffuser vane 11a, the distance is smaller by the amount of the intermediate blade 11b.
[0037]
For this reason, the upper surface part of the partition plate 10a of the diffuser 11 has a higher air flow rate than the tip part in the height direction of the diffuser vane 11a. For this reason, in the diffuser vane 11a height direction of the flow path outlet of the diffuser 11, the pressure is high at the tip of the diffuser vane 11a, and the upper surface of the partition plate 10a, that is, the root of the diffuser vane 11a is lowered. Occurs.
[0038]
Here, the comparison of the air flow in the bent part from the diffuser 11 to the return guide vane 14 with and without the intermediate blade 11b will be described with reference to FIGS. 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.
[0039]
As shown in FIG. 6, in the vicinity of the outlet flow channel portion of the diffuser 11, a pressure difference is generated in which the tip portion in the height direction of the diffuser vane 11 a is high and the root portion of the diffuser vane 11 a is lowered as described above. The air flow 106 on the outer diameter side and the air flow 105 on the inner diameter side of the bending act as a force from the outer diameter side to the inner diameter side of the bending.
[0040]
For this reason, the air flow 106 on the bent outer diameter side and the air flow 105 on the bent inner diameter side can smoothly turn from the diffuser 11 side to the return guide vane 14 side.
[0041]
Moreover, since the force which goes to the inner diameter side from the outer diameter side of the bending works, the secondary flow due to the difference in the centrifugal force of the bending portion is suppressed, and the loss can be reduced.
[0042]
Further, since the air flow 105 on the inner diameter side of the curve adheres and flows on the partition plate 10a side which is the inner diameter side of the curve, it also suppresses the separation region 107 that occurs when the intermediate blade 11b shown in FIG. Loss due to connection and peeling can be reduced, and the efficiency of the electric blower can be improved.
[0043]
Further, the boundary layer developed on the pressure surface 11d side of the diffuser 11 is contracted by the air flow on the inlet side of the intermediate blade 11b, so that the developed boundary layer can be thinned, separation can be suppressed, and loss can be reduced.
[0044]
In the vacuum cleaner, the sucked dust and air are separated by the dust collection bag 305. However, if the dust is fine, it may pass through the dust collection bag 305 and flow into the electric blower 308. The suppression of the peeling by the diffuser 11 described above can prevent the fine dust from adhering and accumulating in the diffuser 11 and the effect of preventing the blockage of the flow path.
[0045]
Further, in the region where the intermediate blade 11b exists, as shown in FIGS. 2 and 3, the expansion of the inter-blade channel width surrounded by the negative pressure surface 11c and the intermediate blade pressure surface 11f of the diffuser vane 11a is performed. Next, a case where the width of the passage between the blades surrounded by the pressure surface 11d of 11a and the intermediate blade negative pressure surface 11e is enlarged will be described.
[0046]
In the electric blower for a vacuum cleaner, on the low flow rate side, the air flow in the diffuser 11 flows toward the negative pressure surface 11c side of the diffuser vane 11a on the upper surface of the partition plate 10a at the overlapping portion of the adjacent diffuser vanes 11a. Bias and fast flow. On the other hand, on the pressure surface 11d side of the diffuser vane 11a, large-scale separation and backflow are likely to occur, and not only pressure recovery at the diffuser 11 is reduced, but also instability occurs in the air flow in the electric blower.
[0047]
The boundary layer developed on the pressure surface 11d side of the diffuser vane 11a is made thinner by reducing the flow of air on the upstream side of the intermediate blade 11b, thereby preventing the boundary layer from developing and reducing the pressure surface of the diffuser vane 11a. By suppressing the deceleration of the flow path surrounded by 11d and the intermediate blade negative pressure surface 11e, separation and backflow are suppressed.
[0048]
Further, in the overlapping surface of the adjacent diffuser vanes 11a, the air flow on the upper surface of the partition plate 10a is biased and the flow velocity is high. By increasing the width of the flow passage surrounded by the blade pressure surface 11f, it is possible to effectively decelerate and recover the pressure.
[0049]
Therefore, on the low air volume side, large-scale separation or backflow in the diffuser 11 that is a factor of instability is suppressed, and pressure recovery is performed by the diffuser 11, so that a reduction in blowing efficiency can be prevented. Further, even when the flow rate is a low flow rate in which dust is collected in the dust collection bag 305 of the vacuum cleaner, the output of a predetermined electric blower can be obtained and the suction force of the vacuum cleaner can be maintained.
[0050]
In addition, among the overlapping portions of the diffuser vane 11a, the flow on the upper surface of the partition plate 10a is uneven and the negative pressure surface 11c side of the diffuser vane 11a, which is a region where the flow velocity is high, is decelerated, By suppressing the deceleration of the flow path surrounded by the blade negative pressure surface 11e, the flow with a bias is corrected and uniformed, thereby preventing the mixing loss due to the non-uniform flow velocity.
[0051]
As shown in FIG. 1, the partition plate 10 a is notched in a substantially triangular shape in the vicinity of the flow path outlet of the diffuser 11, and the flow area of the bent portion is large, so that the air flow 103 flows from the diffuser 11. When turning toward the return guide vane 14, the flow rate can be reduced smoothly without increasing the flow velocity, and the loss can be reduced.
[0052]
FIG. 8 is a plan view of a diffuser according to another embodiment of the present invention.
[0053]
The difference from the diffuser of FIG. 1 is that the downstream end of the intermediate blade 11b is not extended to the vicinity of the flow channel outlet of the diffuser 11 up to a portion where the partition plate 10a is cut out in a substantially triangular shape.
[0054]
In the embodiment of FIG. 8, the end of the partition plate 10a is chamfered in an R shape to eliminate the corners, so that the air flow 103 is transferred from the diffuser vane 11a side to the return guide vane 14 side at the bent portion. Prevents peeling when turning, and can turn smoothly. As a result, the efficiency of the electric blower is improved.
[0055]
Moreover, as shown in FIG. 3, since the upstream tip of the intermediate blade 11b is rounded, it is possible to suppress separation when the upstream tip of the intermediate blade 11b is flowed. Therefore, an increase in loss due to peeling can be suppressed.
[0056]
Although not shown in the figure, a draft is provided so that the tip of the intermediate blade 11b is rounded in the blade height direction or the blade thickness of the intermediate blade 11b is reduced in the blade height direction of the intermediate blade 11b. By providing, it becomes easy to mold the intermediate blade 11b. Even with the intermediate blade 11b molded in this way, an effect equivalent to that of the present embodiment can be obtained.
[0057]
In the embodiment of the present invention, as shown in FIG. 2, the intermediate blade 11b has a structure integrally formed with the partition plate 10a in the same manner as the diffuser vane 11a. You may comprise by another member and may be fixedly arranged on the upper surface of the partition plate 10a.
[0058]
Further, the diffuser vane 11a and the intermediate blade 11b may be integrally formed with the partition plate 10a on the upper surface of the partition plate 10a, and the return guide vane 14 may be integrally formed with the rear surface of the partition plate 10a. It becomes easy.
[0059]
【The invention's effect】
According to the present invention, since the pressure difference is such that the diffuser vane tip is high and the diffuser vane root is low in the diffuser vane height direction of the outlet flow passage of the diffuser, the outer diameter side of the bent portion in the bent portion Therefore, the force toward the inner diameter side works, and the air flow is smoothly turned to the return side. At this time, since a force directed from the outer diameter side to the inner diameter side of the bent portion acts, the secondary flow in the bent portion is suppressed, and the mixing loss due to the non-uniform flow velocity can be reduced.
[0060]
Furthermore, since the secondary flow is suppressed, it is possible to suppress the peeling of the bent portion on the inner diameter side, so that the efficiency of the electric blower can be improved.
[0061]
In addition, on the low airflow side, large-scale separation and backflow in the diffuser, which is the cause of instability, are suppressed, and pressure recovery is performed by the diffuser, so the airflow efficiency is reduced over a wide flow range from low airflow to high airflow. Even in the case of a low flow rate where dust is accumulated in the dust bag of the vacuum cleaner, the output of a predetermined electric blower can be obtained and the suction force 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.
2 is a cross-sectional view of the diffuser of FIG. 1 taken along the line AB.
3 is an enlarged view of a C portion of the diffuser in FIG. 1. FIG.
FIG. 4 is a flow diagram in a bent pipe.
5 is a cross-sectional view taken along the line D-E in FIG. 4;
FIG. 6 is a diagram showing an air flow when an intermediate blade is provided.
FIG. 7 is a diagram showing an air flow 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 longitudinal sectional view of the electric blower housed in the electric vacuum cleaner main body of FIG.
FIG. 10 is an external perspective view of a vacuum cleaner provided with an electric blower according to an embodiment of the present invention.
11 is a longitudinal sectional view of the main body of the vacuum cleaner of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Blower, 2 ... Electric motor, 3 ... Housing, 3c ... Exhaust port, 4 ... Rotary shaft, 5 ... Rotor, 6 ... Stator coil, 7 ... Stator, 9 ... End bracket, 10 ... Static flow path part, 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 blade pressure surface, 12 ... Centrifugal impeller, 13 ... Fan casing , 13a ... Airflow guide, 13b ... Suction port, 14 ... Return guide vane, 15 ... Brush, 32 ... Power supply terminal, 101, 102, 103, 104 ... Air flow, 201 ... Main body of vacuum cleaner, 203 ... Hose, 205 ... Extension pipe, 206 ... suction port, 301 ... lower case, 302 ... upper case, 306 ... dust collecting chamber, 307 ... electric blower room, 308 ... electric blower

Claims (3)

A centrifugal impeller, a diffuser provided on an outer peripheral portion of the centrifugal impeller, and including a partition plate having a plurality of diffuser vanes on the front side and a return guide vane on the back side; and the centrifugal impeller and the diffuser are included. In the electric blower comprising a fan casing ,
A gap is formed between the inner periphery of the fan casing and the outer periphery of the diffuser, and the air flow that passes between the diffuser vanes in the gap changes its direction, and then the flow path passes between the return guide vanes. Configure
An intermediate vane having a height direction dimension smaller than the height direction dimension of the diffuser vane extending from the partition plate is provided on the diffuser vane side and in the vicinity of an air flow path outlet formed between the diffuser vanes. ,
The electric blower characterized in that the sum of the distances between the blades of the intermediate blade and each of the diffuser vanes is smaller than the distance between the blades at the tip of each diffuser vane.   In Claim 1, the flow path width between the blades of the overlapping portion constituted by the intermediate blade and the diffuser vanes on both sides thereof widens from the upstream side toward the downstream side, and the suction surface side blade in the flow path between the blades. The electric blower characterized in that the expansion of the inter-passage channel width is larger than the expansion of the pressure-surface-side inter-blade channel width. In a vacuum cleaner having a dust collection chamber joined to a suction port for sucking dust on a surface to be cleaned, and an electric blower that is arranged behind the dust collection chamber and forms an air flow for sucking the dust from the suction port.
The electric blower according to claim 1 or 2, wherein the electric blower is the electric blower.

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