JP2014055568A - Motor driven blower and vacuum cleaner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve ventilation efficiency of a motor driven blower by reducing ventilation resistance.SOLUTION: A motor driven blower 13 includes an electric motor 30. A centrifugal impeller 23 is fixed to a shaft 31 of the electric motor 30. A main plate 25 is provided below the centrifugal impeller 23. On an upper surface of the main plate 25, a plurality of stator blades 26 which form a flow passage between the upper surface and the centrifugal impeller 23 are provided surrounding the centrifugal impeller 23. On a lower surface of the main plate 25, a plurality of return stator blades 29 which form a flow channel therebetween are provided. Further, the motor driven blower 13 includes a fan guide 14 covering the centrifugal impeller 23 and stator blades 26 therein. A curved part 19 having a curved-surface inner wall along which lower ends of the return stator blades 29 are situated without any gap are connected below the fan guide 14. In the motor driven blower 13, the flow passages change in direction at an angle smaller than 180° above and below the main plate 25.

Description

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

  Conventionally, a vacuum cleaner equipped with an electric blower is known. The electric blower is provided with a casing for storing the main part thereof. Inside the casing, there are provided a main plate and a centrifugal impeller attached above the main plate. The centrifugal impeller takes air from a suction port provided at the upper center of the casing. The taken-in air once spreads in the outer peripheral direction of the casing on the upper side of the main plate, then flows into the lower side of the main plate, and proceeds toward the center of the casing. At this time, the air flow path turns about 180 ° between the upper side and the lower side of the main plate (for example, see Patent Document 1 below).

Japanese Patent No. 4942795 JP 2009-250030 A JP 2005-226608 A

  The electric blower described in Patent Document 1 has a problem that since the flow path is turned by about 180 ° between the upper side and the lower side of the main plate, the ventilation resistance is large and the blowing efficiency tends to deteriorate.

  The present invention has been made to solve the above-described problems. The purpose is to obtain a highly efficient electric blower with reduced ventilation resistance of the flow path and a vacuum cleaner equipped with such an electric blower.

  An electric blower according to the present invention includes an electric motor, a centrifugal impeller fixed to the rotating shaft of the electric motor, a plurality of stationary blades that are provided so as to surround the centrifugal impeller, and that form a flow path therebetween. Including a main plate that supports the stator blades on one side, a plurality of return stator blades whose one end is supported by the other surface of the main plate and that forms a flow path between them, a centrifugal impeller, and a stator blade The fan guide includes a curved inner wall having a curved inner wall with which the other side end of the return stationary blade is in contact and connected to the fan guide.

  A vacuum cleaner according to the present invention includes the electric blower.

  ADVANTAGE OF THE INVENTION According to this invention, in the vacuum cleaner carrying an electric blower and an electric blower, ventilation resistance can be reduced and ventilation efficiency can be improved.

It is the schematic of the vacuum cleaner 10 which shows Embodiment 1 of this invention. It is sectional drawing of the perpendicular direction of the electric blower 13 in Embodiment 1 of this invention. It is a top view of the diffuser 24 in Embodiment 1 of this invention. It is a perspective view of the diffuser 24 in Embodiment 1 of this invention. It is a top view of the diffuser 24 in Embodiment 2 of this invention. It is a top view which shows the subject of the diffuser 24 in Embodiment 1 of this invention. It is sectional drawing of the perpendicular direction of the electric blower 13 in Embodiment 3 of this invention.

  Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals. The overlapping description will be simplified or omitted as appropriate. Moreover, in each figure, the flow of air is shown by the arrow.

Embodiment 1 FIG.
FIG. 1 is a schematic diagram of a vacuum cleaner 10 showing Embodiment 1 of the present invention.
As shown in FIG. 1, the vacuum cleaner 10 includes a vacuum cleaner body 11. The electric vacuum cleaner main body 11 includes a dust collecting unit 12 that collects dust sucked together with air. The vacuum cleaner body 11 includes an electric blower 13 that performs a suction operation.

Next, the structure of the electric blower 13 will be described with reference to FIGS.
FIG. 2 is a vertical sectional view of the electric blower 13 in the present embodiment. In this specification, unless otherwise specified, the direction is designated with reference to the vertical direction shown in FIG.

  As shown in FIG. 2, the electric blower 13 includes a fan guide 14. The outer peripheral portion 15 of the fan guide 14 has a curved inner wall. A bell mouth 16 is provided at the center of the upper surface of the fan guide 14. A suction port 17 is formed inside the bell mouth 16.

  A bracket 18 is connected below the fan guide 14. The bracket 18 includes a curved portion 19 whose inner wall is formed with a curved surface. A motor frame 20 is coupled below the bracket 18. The motor frame 20 forms the side surface and the bottom surface of the electric blower 13. A plurality of discharge holes 21 are provided on the side surface of the motor frame 20.

  The electric blower 13 includes a centrifugal impeller 23 inside. The centrifugal impeller 23 is disposed below the suction port 17 so as to be included in the fan guide 14. A diffuser 24 is provided below the centrifugal impeller 23.

  The diffuser 24 includes a circular main plate 25. A plurality of stationary blades 26 are provided on the upper surface of the main plate 25. The stationary blade 26 is included in the fan guide 14 and is provided so as to surround the side of the centrifugal impeller 23.

  Further, the stationary blade 26 includes an extending portion 27 that extends downward from the main plate 25 from the outer end portion thereof to the outer peripheral end of the main plate 25. The extension part 27 is formed so that the extension amount increases toward the outside.

  As shown in FIG. 2, a gap 28 serving as a flow path from the upper side to the lower side of the main plate 25 is provided between the fan guide 14 and the diffuser 24. A plurality of return vanes 29 are provided on the lower surface of the main plate 25.

  FIG. 3 is a top view of the diffuser 24 in the present embodiment. As shown in FIG. 3, a plurality of stationary blades 26 are annularly arranged on the upper surface of the main plate 25. Between the blades of the stationary blade 26, a flow path is formed from the center of the main plate 25 to the outside. Further, the distance from the center of the main plate 25 to the outer end portion of the stationary blade 26 (hereinafter referred to as “radius of the stationary blade 26”) is formed to be larger than the radius of the main plate 25. In other words, the stationary blade 26 is formed so as to protrude outward from the outer periphery of the main plate 25.

  FIG. 4 is a perspective view of the diffuser 24 shown in FIG. As shown in FIG. 4, a plurality of return vanes 29 are annularly arranged on the lower surface of the main plate 25. Between the blades of the return vane 29, a flow path from the outer peripheral end of the main plate 25 toward the center is formed.

  As shown in FIG. 2, the return stator blade 29 is formed such that the lower end portion on the inner peripheral side is positioned below the lower end portion on the outer peripheral side. Further, the return vane 29 is formed such that the lower end portion thereof is along the inner wall of the curved portion 19 without a gap. That is, the return stationary blade 29 is formed so as to smoothly expand in the vertical direction as it goes inward. Coupled with this shape, the flow passage cross-sectional area of the return vane 29 is provided so as to smoothly expand.

  As shown in FIG. 2, the electric blower 13 includes an electric motor 30 below the diffuser 24. The electric motor 30 includes a shaft 31 at the center. The shaft 31 is rotatably supported by the main plate 25 and the motor frame 20. A centrifugal impeller 23 is fixed to the upper portion of the shaft 31.

  In addition, the electric motor 30 includes a winding 32. The winding 32 is arranged so that a part thereof is located on the side of the bending portion 19. In other words, the winding 32 is provided so that a part of its side faces the inner peripheral side end of the flow path formed by the return vane 29. A carbon brush 33 is provided below the winding 32.

Next, the operation of the electric blower 13 will be described with reference to FIG.
When electric power is supplied to the electric motor 30, the centrifugal impeller 23 rotates. The centrifugal impeller 23 takes air into the electric blower 13 from the suction port 17. The taken-in air is boosted and accelerated by the centrifugal impeller 23 and sent to the stationary blade 26 side. The air is decelerated and pressurized between the blades of the stationary blade 26. Thereafter, the air passes through the gap 28 and flows into the return stationary blade 29 side. The air flowing in from the gap 28 flows through the flow path of the return vane 29 toward the center of the motor frame 20. At this time, the air cools the winding 32 from above and from the side. The air that has cooled the winding 32 flows downward in the motor frame 20. At this time, after the electric motor 30 is cooled, the air is discharged from the discharge hole 21 to the outside of the electric blower 13.

  As described above, the inner wall of the outer peripheral portion 15 of the fan guide 14 and the curved portion 19 of the bracket 18 has a curved surface. That is, the outer peripheral side of the flow path from the stationary blade 26 to the returning stationary blade 29 is formed with a curve. The return vane 29 is formed such that the lower end portion on the inner peripheral side is positioned below the lower end portion on the outer peripheral side. In other words, the return stationary blade 29 is formed such that the lower end portion thereof moves away from the main plate 25 as it goes from the outer peripheral side to the inner peripheral side. Thereby, the flow path is turned from the upper side to the lower side of the main plate 25 at an angle smaller than 180 °. For this reason, the air flow from the stationary blade 26 side can be smoothly guided to the return stationary blade 29. Therefore, the ventilation resistance of a flow path can be reduced and the ventilation efficiency of the electric blower 13 can be improved.

  Further, as described above, the return vane 29 is formed such that the lower end portion thereof is along the inner wall of the bending portion 19 without a gap. For this reason, the air does not flow so as to cross the return vane 29 and is efficiently guided to the electric motor 30 side. Therefore, the ventilation efficiency of the electric blower 13 can be improved.

  Further, as described above, the flow passage cross-sectional area of the return vane 29 is smoothly expanded. For this reason, pressure is gradually recovered in the flow path of the return vane 29, and unstable flow such as local backflow due to rapid expansion of the flow path does not occur. Therefore, the air blowing efficiency can be improved in the flow path of the return vane 29 regardless of the flow rate.

  Further, as described above, the winding 32 is provided so that a part of the side surface thereof faces the inner peripheral side end of the flow path of the return vane 29. For this reason, the winding 32 can be cooled not only from above but also from the side to reduce the winding resistance. Therefore, the efficiency of the electric motor 30 can be improved.

  Further, as described above, the stationary blade 26 is formed so as to protrude outward from the outer periphery of the main plate 25. When the stationary blade 26 does not protrude outside the main plate 25, a large annular gap is formed between the fan guide 14 and the diffuser 24. If such a gap exists, an unstable flow due to rapid expansion of the flow path may occur, and ventilation resistance may increase. On the other hand, in the present embodiment, it is possible to reduce the ventilation resistance while preventing a rapid expansion of the flow path from the stationary blade 26 side to the return stationary blade 29 side. Therefore, the ventilation efficiency of the electric blower 13 can be improved.

  Further, as described above, the stationary blade 26 is provided with the extending portion 27. For this reason, the local backflow between the stationary blade 26 and the return stationary blade 29 can be prevented while reducing the ventilation resistance of the flow path from the stationary blade 26 side to the returning stationary blade 29 side. Therefore, the flow from the stationary blade 26 side can be smoothly guided back to the stationary blade 29 side. As a result, the blowing efficiency of the electric blower 13 can be improved.

  Further, as described above, the extension portion 27 is formed so that the extension amount increases toward the outside. For this reason, the flow flowing out from the stationary blade 26 side can be smoothly guided to the returning stationary blade 29 side before colliding with the fan guide 14. Therefore, the ventilation resistance of the flow path can be reduced and the input can be reduced.

  Further, as described above, the main plate 25 is formed in a circular shape. For this reason, the shape of the gap 28 between the stationary blade 26 and the fan guide 14 is uniform over the entire circumference of the main plate 25. Accordingly, it is possible to prevent a sudden expansion of the flow path from the stationary blade 26 side to the returning stationary blade 29 side and reduce the ventilation resistance over the entire circumference of the stationary blade 26. As a result, the blowing efficiency of the electric blower 13 can be improved.

  In the present embodiment, the flow passage cross-sectional area of the return vane 29 is formed so as to smoothly expand, but this is not necessarily essential in the present invention.

Embodiment 2. FIG.
FIG. 5 is a top view of the diffuser 24 according to the second embodiment of the present invention. The present embodiment is the same as the first embodiment except for the structure of the diffuser 24. Hereinafter, differences from the first embodiment will be described.

FIG. 6 is a diagram for explaining the problem of the diffuser 24 in the first embodiment.
As shown in FIG. 6, in the first embodiment, the radius of the fan guide 14 is formed larger than the radius of the stationary blade 26. That is, a narrow gap 34 exists between the fan guide 14 and the outer end portion of the stationary blade 26. For this reason, in the first embodiment, separately from the flow from between the blades of the stationary blade 26 to the return stationary blade 29 side, the flow flows from between the blades of the stationary blade 26 to the adjacent blades through the narrow gap 34. Occurs. The latter flow mixes with the flow between adjacent wings and generates a mixing loss. As a result, an increase in pressure between the blades of the stationary blade 26 is hindered, and the efficiency of the electric blower 13 may be reduced.

  On the other hand, as shown in FIG. 5, in the present embodiment, the radius of the fan guide 14 and the radius of the stationary blade 26 are substantially the same. That is, the outer end portion of the stationary blade 26 is in contact with the inner wall of the fan guide 14. For this reason, all the air that has passed between the blades of the stationary blade 26 flows into the stationary blade 29 side. Therefore, in this embodiment, no mixing loss occurs between the vanes of the stationary blade 26. As a result, the blowing efficiency of the electric blower 13 can be improved.

Embodiment 3 FIG.
FIG. 7 is a vertical cross-sectional view of electric blower 13 according to Embodiment 3 of the present invention. The present embodiment is the same as the first embodiment except for the structure of the bending portion 19.

  In the first embodiment, the bending portion 19 includes a plurality of flow paths formed between the return vanes 29. The plurality of flow paths are mainly divided into a first flow path for sending air to the winding 32 or the carbon brush 33 and a second flow path for sending air mainly to a region where the winding and the carbon brush are not present. It is done.

  In the present embodiment, the sub discharge hole 35 is formed in the vicinity of the inner peripheral side end of the flow path of the return stator blade 29 where the inner peripheral end is not above the winding 32 and the carbon brush 33. ing. That is, the sub discharge hole 35 is formed in the vicinity of the inner peripheral side end of the second flow path.

  Thereby, a part of air is discharged from the sub discharge hole 35 of the second flow path, and the ventilation resistance of the flow path of the return stationary blade 29 can be reduced. Moreover, since the sub discharge hole 35 is installed in the vicinity of the inner peripheral side end of the flow path, the flow of the discharged air is decelerated compared to the case where it is installed on the outer peripheral side of the flow path. For this reason, it is possible to suppress jet noise when air is discharged and to reduce noise.

  On the other hand, the air flow sent from the first flow path cools the winding 32 or the carbon brush 33. By cooling the winding 32, the winding resistance can be reduced and the efficiency of the electric motor 30 can be improved. Moreover, the electric blower 13 with a long life can be obtained by cooling the carbon brush 33 that generally has a low life under a high temperature environment.

  As described above, in the present embodiment, it is possible to secure the air flow necessary for cooling the winding 32 and the carbon brush 33 while reducing the ventilation resistance of the flow path of the return stationary blade 29. As a result, the electric blower 13 with high efficiency and long life can be obtained.

  In the present embodiment, the configuration in which the sub-ejection hole 35 is provided near the inner peripheral side end of the flow path is combined with the configuration in which the sub-discharge hole 35 is provided in the second flow path. However, these configurations are not necessarily combined, and may be implemented separately.

DESCRIPTION OF SYMBOLS 10 Vacuum cleaner, 11 Vacuum cleaner main body, 12 Dust collection part, 13 Electric blower, 14 Fan guide, 15 Outer peripheral part, 16 Bell mouth, 17 Suction port, 18 Bracket, 19 Curved part, 20 Motor frame, 21 Discharge hole , 23 Centrifugal impeller, 24 Diffuser, 25 Main plate, 26 Stator vane, 27 Extension part, 28 Gap, 29 Return vane, 30 Motor, 31 Shaft, 32 Winding, 33 Carbon brush, 34 Narrow gap, 35 Sub discharge Hole

Claims (10)

An electric motor,
A centrifugal impeller fixed to the rotating shaft of the electric motor;
A plurality of stationary blades provided so as to surround the centrifugal impeller, and forming a flow path between them;
A main plate supporting the stationary blade on one side;
A plurality of return vanes having one side end supported by the other surface of the main plate and forming a flow path therebetween;
A fan guide containing the centrifugal impeller and the stationary blade;
A curved portion connected to the fan guide, having a curved inner wall with which the other side end of the return vane contacts;
With
The electric blower characterized in that the direction of the flow path is turned at an angle smaller than 180 ° between the one surface side and the other surface side of the main plate.   2. The electric blower according to claim 1, wherein the return stationary blade is formed so that the other side end is away from the main plate as it goes from the outer peripheral side to the inner peripheral side. The electric motor comprises a winding on the inner side of the return vane;
3. The electric blower according to claim 1, wherein a part of a side surface of the winding is opposed to an inner peripheral side end portion of a flow path formed between blades of the return stationary blade.   The stationary blade is formed so as to protrude outward from the outer peripheral end of the main plate, and an extending portion extending from the outer end portion to the outer peripheral end of the main plate toward the return stationary blade side from the main plate. It has, The electric blower of any one of Claim 1 thru | or 3 characterized by the above-mentioned.   5. The electric blower according to claim 1, wherein an inner wall of a portion of the fan guide that includes the stationary blade is formed as a curved surface. 6.   The flow path formed between blades of the return stator blade is provided so that a cross-sectional area gradually increases from the outer peripheral side of the main plate toward the central side of the main plate. The electric blower of any one of Claims.   The electric blower according to any one of claims 1 to 6, wherein an outer end portion of the stationary blade is in contact with an inner wall of the fan guide.   The electric blower according to any one of claims 1 to 7, wherein the curved portion includes a sub discharge hole in the vicinity of an inner peripheral side end portion of the return stationary blade. The electric motor comprises a carbon brush;
The flow path formed between the blades of the return vane is mainly a first flow path for sending air to the winding or the carbon brush, and air mainly in a region where the winding and the carbon brush are not present. A second flow path for sending
The electric blower according to any one of claims 1 to 8, wherein the curved portion includes the sub-ejection hole in the second flow path.   The vacuum cleaner carrying the electric blower of any one of Claims 1 thru | or 9.

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