JPWO2017154151A1 - Electric blower and vacuum cleaner - Google Patents

Abstract

A highly efficient electric blower and a vacuum cleaner equipped with the same can be obtained. The electric blower (6) includes a centrifugal impeller (11), a fan cover (16), and an electric part. The centrifugal impeller (11) includes a disk-shaped hub (23) having a surface, an annular shroud (24), and a plurality of blades (25). A plurality of rotor blades (25) are provided in the circumferential direction of the shroud (24) between the hub (23) and the shroud (24). The fan cover (16) is installed outside the shroud (24) in the axial direction of the centrifugal impeller (11) so as to enclose the centrifugal impeller (11). The fan cover (16) has an opening (18) having a center point on the rotation axis. The electric part rotates the centrifugal impeller. In the moving blade (25), the first portion located on the rotating shaft side is located inside the outer peripheral edge of the opening (18).

Description

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

  Conventionally, an electric blower used for a vacuum cleaner is known. The electric blower rotates an annular shroud, a hub disposed opposite the shroud, a plurality of circumferentially disposed moving blades between the shroud and the hub, and a shroud, the hub, and the moving blade. A centrifugal impeller. In such an electric blower, for high efficiency, the airflow flowing out from the centrifugal impeller outlet does not flow into the centrifugal impeller inlet again in the gap between the centrifugal impeller inlet and the fan cover containing the centrifugal impeller. Some have leakage prevention means (for example, see FIGS. 1 to 3 of JP2013-60839A (Patent Document 1) and JP2000-154797A).

JP 2013-60839 A JP 2000-154797 A

  As disclosed in Japanese Patent Application Laid-Open No. 2013-60839, a seal member that does not hinder the rotation of the centrifugal impeller may be used as the leakage preventing means provided in the gap between the centrifugal impeller inlet and the fan cover. In this case, when the centrifugal impeller rotates, the shroud and the seal member are rubbed and the seal member is worn. As a result, the leakage preventing effect of the seal member is reduced. When the leakage prevention effect is lowered, the circulation flow in which the airflow flowing out from the centrifugal impeller outlet re-inflows from the centrifugal impeller inlet increases. When such a circulating flow increases, there is a problem that the load applied to the moving blade increases and the efficiency decreases.

  Also, as shown in Japanese Patent Application Laid-Open No. 2000-154797, there is a case in which a groove is provided on the inner peripheral side end surface of the shroud and the inner peripheral side end of the fan cover is fitted in this groove as a seal structure. is there. However, even with such a configuration, the airflow re-entering the centrifugal impeller inlet from the seal structure is mixed with the main flow of air sucked from the extending impeller inlet. When such re-inflowing airflow is mixed with the mainstream at the centrifugal impeller inlet, there is a problem that the collision loss of the moving blade leading edge increases and the efficiency also decreases.

  This invention is made | formed in order to solve the above subjects, and the objective of this invention is obtaining the highly efficient electric blower and the vacuum cleaner carrying it.

  The electric blower according to the present invention includes a centrifugal impeller, a fan cover, and an electric part. The centrifugal impeller includes a disk-shaped hub having a surface, an annular shroud, and a plurality of moving blades. The shroud faces the surface of the hub. A plurality of rotor blades are provided in the circumferential direction of the shroud between the hub and the shroud. The bucket is connected to a hub and a shroud. The fan cover is installed outside the shroud in the direction of the rotation axis of the centrifugal impeller so as to include the centrifugal impeller. The fan cover has an opening having a center point on the rotation axis. The electric part rotates the centrifugal impeller. The moving blade includes a first portion located inside the outer peripheral edge of the opening.

  In the electric blower of the present invention, the inner wall of the opening of the fan cover is located on the outer peripheral side (downstream side) of the first portion located on the upstream side in the air flow direction in the rotor blade. A gap between the inner wall of the opening of the fan cover and the shroud is a flow path of air (circulation flow) re-entering from the centrifugal impeller outlet to the centrifugal impeller inlet. Therefore, the circulating flow flows into the centrifugal impeller from the downstream side of the first portion of the moving blade. Therefore, when the circulating flow flows upstream from the first portion of the moving blade, the main flow and the circulating flow are mixed to generate a complicated air flow. As a result, the load on the moving blade is increased and the efficiency is increased. Can be prevented from occurring. As a result, a highly efficient electric blower can be realized. Furthermore, a highly efficient electric vacuum cleaner can be obtained by mounting this electric blower.

It is a schematic diagram of the vacuum cleaner which shows embodiment of this invention. It is a cross-sectional schematic diagram of the perpendicular direction of the electric blower in embodiment of this invention. It is a cross-sectional schematic diagram of the perpendicular direction which shows a part of electric blower in embodiment of this invention. It is a perspective schematic diagram of the centrifugal impeller in embodiment of this invention. It is a cross-sectional schematic diagram of the perpendicular direction which shows a part of moving blade of the centrifugal impeller in embodiment of this invention. It is a cross-sectional schematic diagram of the perpendicular direction which shows a part of modification of the moving blade shown in FIG.

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

<Configuration of electric vacuum cleaner according to this embodiment>
FIG. 1 is a schematic view of a vacuum cleaner according to an embodiment of the present invention. In FIG. 1, the present vacuum cleaner includes a vacuum cleaner body 1, a suction tool 4, a dust collecting unit 5, an electric blower 6, and a discharge port 7. The suction tool 4 is connected to the main body 1 of the vacuum cleaner by a hose 2 and an extension pipe 3 as a conduit, and sucks air in a portion to be cleaned. The hose 2 is connected to the main body 1 of the vacuum cleaner. The extension pipe 3 is connected to the tip end side of the hose 2. The suction tool 4 is connected to the tip of the extension pipe 3.

  The dust collection unit 5 is provided inside the vacuum cleaner main body 1, communicates with the suction tool 4, and stores sucked air dust. The electric blower 6 is provided inside the vacuum cleaner main body 1 and sucks air from the suction tool 4 to the dust collecting unit 5. The electric blower 6 is an electric blower according to an embodiment of the present invention described later. The discharge port 7 is provided outside the vacuum cleaner main body 1 and discharges the air after being collected by the dust collecting unit 5 to the outside of the vacuum cleaner main body 1. The discharge port 7 is provided in the back of the vacuum cleaner main body 1 as shown in FIG.

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

<Configuration of electric blower according to this embodiment>
FIG. 2 is a schematic cross-sectional view in the vertical direction of the electric blower according to the embodiment of the present invention. In FIG. 2, the arrows indicate the air flow. FIG. 3 is a schematic cross-sectional view in the vertical direction showing a part of the electric blower shown in FIG. 4 is a schematic perspective view of a centrifugal impeller constituting the electric blower shown in FIG. FIG. 5 is a schematic cross-sectional view in the vertical direction showing a part of the moving blade of the centrifugal impeller in the embodiment of the present invention.

  As shown in FIGS. 2 to 5, the electric blower 6 according to the embodiment of the present invention includes a centrifugal impeller 11, a fan cover 16, and an electric unit 9. The centrifugal impeller 11 includes a disk-shaped hub 23 having a surface, an annular shroud 24, and a plurality of moving blades 25. The shroud 24 faces the surface of the hub 23. A plurality of moving blades 25 are provided in the circumferential direction of the shroud 24 between the hub 23 and the shroud 24. The moving blade 25 is connected to the hub 23 and the shroud 24. The fan cover 16 is installed outside the shroud 24 in the axial direction of the centrifugal impeller 11 so as to include the centrifugal impeller 11. The electric unit 9 rotates the centrifugal impeller 11. The electric unit 9 is disposed inside the electric blower 6. The motorized part 9 includes a shaft 10. The centrifugal impeller 11 is fixed to the shaft 10. The electric part 9 rotates the centrifugal impeller 11 by rotating the shaft 10. The electric motor 9 is an electric motor such as a motor.

  A diffuser 15 is disposed between the electric unit 9 and the centrifugal impeller 11. The diffuser 15 includes a plurality of stationary blades 12, a plurality of return stationary blades 13, and a main plate 14. The plurality of stationary blades 12 are disposed on the outer peripheral side of the centrifugal impeller 11. The return vane 13 is disposed so as to be adjacent to the vane 12 in the rotation axis direction that is the extending direction of the shaft 10. The main plate 14 is located between the stationary blade 12 and the return stationary blade 13, and connects the stationary blade 12 and the returning stationary blade 13.

  As described above, the fan cover 16 is provided on the upper portion of the centrifugal impeller 11. The fan cover 16 includes the centrifugal impeller 11 and the stationary blades 12 of the diffuser 15. The outer diameter of the fan cover 16 is larger than the outer diameter of the stationary blade 12. A bell mouth 18 as an opening having a center point on the rotation axis of the centrifugal impeller 11 is formed at the center of the fan cover 16. Here, the center point of the bell mouth 18 is the center point of a circle formed by the outer peripheral edge if the planar shape of the outer peripheral edge of the bell mouth 18 is circular. When the planar shape of the outer periphery of the bell mouth 18 is a shape other than a circular shape (for example, a polygonal shape), the center point of the bell mouth 18 may be the center of gravity of the planar shape. Further, having a center point on the rotation axis does not only mean that the rotation axis and the center point overlap, but also includes a case where the center point is included in a cylindrical region having a radius of 5 mm centered on the rotation axis, for example. means. From a different point of view, the bell mouth 18 is provided at a position facing the suction port 17 of the centrifugal impeller 11. From a different point of view, the fan cover 16 is formed with a bell mouth 18 having a center point on the rotation axis of the centrifugal impeller 11. A gap 21 is provided between the fan cover 16 and the diffuser 15 and serves as a gas flow path from the stationary blade 12 to the returning stationary blade 13 on the outer peripheral side of the stationary blade 12.

  The moving blade 25 of the centrifugal impeller 11 includes a first portion 36 located inside the bell mouth 18 as shown in FIG. The first portion 36 has an end surface 36 </ b> A that faces the inner wall of the bell mouth 18 in the fan cover 16. In the shroud 24, the second portion 34 located on the rotating shaft side is disposed so as to face the end surface 36 </ b> A of the first portion 36. The second portion 34 is formed so as to extend in a direction along the rotation axis indicated by a one-dot chain line located at the right end of FIG. In the shroud 24, the second portion 34 has an annular planar shape as shown in FIG. The inner wall of the bell mouth 18 is located between the end face 36 </ b> A and the second portion 34. From another point of view, a region sandwiched between the end surface 36A of the first portion 36 of the rotor blade 25 and the second portion 34 of the shroud 24 constitutes a groove portion 35. The inner wall of the bell mouth 18 is located inside the groove portion 35. The inner wall of the bell mouth 18 extends along the second portion 34 of the shroud 24. The inner wall of the bell mouth 18 is an end portion on the inner peripheral side of the fan cover 16. The inner wall of the bell mouth 18 extends along the end face 36 </ b> A of the first portion 36. The position of the top surface 36 </ b> B of the first portion 36 is disposed at a position farther from the lower end 18 </ b> A of the inner wall of the bell mouth 18 when viewed from the hub 23. That is, the first portion 36 of the moving blade 25 is located on the inner side of the outer peripheral edge of the bell mouth 18 of the fan cover 16 and extends upward from the lower end of the wall portion of the bell mouth 18.

  As shown in FIGS. 4 and 5, the first portion 36 includes an inclined portion 26 that is inclined by an inclination angle θ toward the rotation direction R of the moving blade 25 with respect to the rotation axis direction. Here, the inclination angle θ refers to an angle formed by the rotational axis direction of the centrifugal impeller 11 and a line segment passing through the central portion in the thickness direction of the inclined portion 26. Note that a broken line arrow R in FIG.

  A bracket 19 that is connected to the fan cover 16 and encloses the return vane 13 is disposed on the side surface of the electric blower 6. In addition, a motor frame 20 that is connected to the bracket 19 and encloses the electric unit 9 is provided on a side surface of the electric blower 6. The motor frame 20 is provided with several discharge holes 22 through which the air that has passed through the centrifugal impeller 11, the diffuser 15, and the electric motor 9 is discharged.

<Effects of electric blower>
2 to 5, the bell mouth 18 as an opening of the fan cover 16 is provided on the outer peripheral side (downstream side) of the first portion 36 located on the upstream side in the air flow direction in the rotor blade 25. The inner wall of is located. A gap between the inner wall of the bell mouth 18 and the second portion 34 of the shroud 24 is a flow path of air (circulation flow) re-entering from the centrifugal impeller outlet to the centrifugal impeller inlet as shown by an arrow 41 in FIG. It has become. Therefore, the circulating flow flows into the centrifugal impeller from the downstream side of the first portion 36 of the moving blade 25. Therefore, a phenomenon in which a complex air flow is generated by mixing the main flow indicated by the arrow 42 in FIG. 3 and the circulation flow when the circulation flow flows into the upstream side of the first portion 36 of the rotor blade 25. Can be prevented. Therefore, compared to the case where such a complicated air flow is generated on the upstream side of the moving blade 25, the collision loss at the leading edge of the moving blade 25 (the edge of the first portion 36) can be reduced. As a result, the load applied to the moving blade 25 can be reduced, and the highly efficient electric blower 6 can be realized. Furthermore, by mounting this electric blower 6, a highly efficient vacuum cleaner can be obtained.

  In the electric blower 6 described above, the first portion 36 has an end surface 36 </ b> A that faces the inner wall of the bell mouth 18 in the fan cover 16. In the shroud 24, the second portion 34 located on the rotating shaft side is disposed so as to face the end surface 36 </ b> A of the first portion 36. The inner wall of the bell mouth 18 is located between the end face 36 </ b> A and the second portion 34. By adopting such a configuration, the path through which the circulating flow flows into the centrifugal impeller is a narrow region between the second portion 34 of the shroud 24 and the inner wall of the bell mouth 18 as shown by an arrow 41 in FIG. can do. For this reason, the inflow amount of the circulation flow can be reduced by setting the distance between the second portion 34 and the inner wall of the bell mouth 18 to be sufficiently narrow. For example, the distance can be 0.1 mm or more and 0.3 mm or less. In this way, the load on the rotor blade 25 can be reliably reduced.

  In the electric blower 6 described above, the inner wall of the bell mouth 18 extends along the second portion 34 of the shroud 24. In this case, since the flow resistance in the gap between the inner wall of the bell mouth 18 and the second portion 34 can be increased, the inflow amount of the circulating flow from the gap can be effectively reduced. For example, as shown in FIG. 3, the length of the region where the second portion 34 and the inner wall of the bell mouth 18 face each other in the direction along the rotation axis is 1 mm or more and 5 mm or less, more preferably 2 mm or more and 4 mm or less. Can do.

  In the electric blower 6 described above, the first portion 36 includes the inclined portion 26 that is inclined by the inclination angle θ toward the rotation direction R of the rotor blade 25 with respect to the rotation axis direction. Then, as shown in FIG. 5, the inclination angle θ is set so that the extending direction of the inclined portion 26 matches the direction of the moving blade inlet relative speed (the combined peripheral speed of the moving blade and the absolute speed of the moving blade inlet). Can be set. In this case, the collision loss between the leading edge of the moving blade 25 and the main flow can be reduced, and the load on the moving blade 25 can be reduced.

<Operation and effect of vacuum cleaner>
Next, the operation of the vacuum cleaner will be described.

  In the electric vacuum cleaner configured as described above, when electric power is supplied to the motor unit 9, the shaft 10 rotates. As the shaft 10 rotates, the centrifugal impeller 11 attached to the shaft 10 rotates and sucks air from the suction port 17. Thereby, the air on the surface to be cleaned is sucked into the vacuum cleaner body 1 through the hose 2, the extension pipe 3, and the suction tool 4 connected to the vacuum cleaner body 1. The air sucked into the electric vacuum cleaner main body 1 is collected in the dust collecting unit 5. Thereafter, the air discharged from the dust collecting unit 5 passes through the bell mouth 18 of the electric blower 6 and is sucked from the suction port 17 of the centrifugal impeller 11. The air sucked into the centrifugal impeller 11 is increased in pressure and accelerated by the centrifugal impeller 11, and travels radially outward while turning. Part of the air discharged from the centrifugal impeller 11 becomes a circulating flow that re-enters the suction port of the centrifugal impeller 11 through the gap between the shroud 24 and the fan cover 16. On the other hand, most of the air discharged from the centrifugal impeller 11 is decelerated and boosted between the vanes of the stationary blade 12 of the diffuser 15. Thereafter, the air passes through the gap 21 between the diffuser 15 and the fan cover 16. Further, the air is guided to the electric unit 9 side by the return stationary blade 13 to cool the electric unit 9. Thereafter, air is discharged from the discharge hole 22 provided in the motor frame 20 to the outside of the electric blower. And air is discharged | emitted from the discharge port 7 provided in the vacuum cleaner main body 1 to the outer side of the vacuum cleaner main body 1. FIG.

  Since the electric vacuum cleaner described above uses the electric blower 6 configured as shown in FIGS. 2 to 5, after the air is discharged from the centrifugal impeller 11, the gap between the shroud 24 and the fan cover 16 is formed. Air that re-enters the centrifugal impeller 11 through the intermediate blade (groove portion 35) of the blade 25 is supplied to the space between the adjacent blades 25. For this reason, the re-inflowing air does not disturb the mainstream air flow on the upstream side of the rotor blade 25. Therefore, it is possible to suppress the occurrence of the problem that the load on the rotor blade 25 increases due to the disturbance of the mainstream air flow. As a result, a highly efficient electric blower and vacuum cleaner can be obtained. Moreover, in the electric blower 6 having the above-described configuration, the air flow discharged from the centrifugal impeller 11 easily flows into the fan cover 16 side of the stationary blade 12. For this reason, since it becomes easy to decelerate and pressurize in the stationary blade 12, a vacuum cleaner provided with a high static pressure and a highly efficient electric blower can be obtained.

<Configuration and operation effect of modified example of electric blower>
FIG. 6 is a schematic cross-sectional view in the vertical direction of the rotor blade 25 in a modification of the embodiment of the present invention. The electric blower including the moving blade 25 shown in FIG. 6 basically has the same configuration as the electric blower shown in FIGS. 2 to 5, but the shape of the inclined portion 26 of the moving blade 25 is different. Specifically, in the moving blade of the electric blower, the portion 26C on the shroud 24 (see FIG. 3) side of the inclined portion 26 has a first inclination angle θ1 with respect to the rotation axis direction. In the inclined portion 26, the portion 26B closer to the hub 23 than the portion 26C has a second inclination angle θ2 with respect to the rotation axis direction. The first inclination angle θ1 is larger than the second inclination angle θ2. Further, in the inclined portion 26, the portion 26A closer to the hub 23 than the portion 26B has a third inclination angle with respect to the rotation axis direction. The third inclination angle is, for example, 0 °. For this reason, the first inclination angle θ1 is larger than the third inclination angle. Further, the second inclination angle θ2 is also larger than the third inclination angle. Note that an arbitrary value can be selected as long as the third inclination angle is smaller than the first and second inclination angles.

  By providing such a structure, the load concerning the moving blade 25 can be reduced effectively similarly to the electric blower shown in FIGS.

  Here, the main flow that flows into the moving blade 25 generally tends to flow into the hub 23 side. Therefore, the amount of air flowing into the shroud 24 is reduced. When the inflow air volume on the shroud 24 side is small, the absolute speed on the shroud 24 side becomes small. As a result, the relative speed on the shroud 24 side is more radial than the relative speed on the hub 23 side. The inclined portion 26 of the moving blade 25 shown in FIGS. 5 and 6 has an inclination angle θ on the shroud 24 (see FIG. 3) side larger than an inclination angle on the hub 23 side, and is peeled in the radial direction. The leading edge shape of the rotor blade 25 follows this flow. For this reason, on the shroud 24 side of the moving blade 25, the collision loss between the leading edge of the moving blade 25 and the main flow can be reduced, and the load applied to the moving blade 25 can be effectively reduced.

  As described above, the electric blower 6 of the present embodiment does not prevent the circulation flow flowing through the gap between the shroud 24 and the fan cover 16 by using the seal member, but the shape and positional relationship between the shroud 24 and the fan cover 16. Suppress with. Further, the circulating flow does not flow between the blades of the moving blade 25 and collide with the leading edge of the moving blade 25. For this reason, there is little decrease in the load reduction effect of the moving blade 25 due to deterioration over time, and the performance can be maintained over a long period of time.

  The electric blower as described above is not limited to a household or commercial vacuum cleaner, and can be applied to any device using an electric blower such as a hand dryer. As a result, a highly efficient and long-life device can be realized.

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

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

  DESCRIPTION OF SYMBOLS 1 Vacuum cleaner main body, 2 hose, 3 extension pipe, 4 suction tool, 5 dust collecting part, 6 electric blower, 7 discharge port, 8 rear wheel, 9 electric part, 10 shaft, 11 centrifugal impeller, 12 stationary blade, 13 Return vane, 14 Main plate, 15 Diffuser, 16 Fan cover, 17 Suction port, 18 Bell mouth, 18A Lower end, 19 Bracket, 20 Motor frame, 21 Clearance, 22 Discharge hole, 23 Hub, 24 Shroud, 25 Rotor blade, 26 slope part, 26A-26C part, 34 2nd part, 35 groove part, 36 1st part, 36A end face, 36B top face, 41, 42 arrow.

The electric blower according to the present invention includes a centrifugal impeller, a fan cover, and an electric part. The centrifugal impeller includes a disk-shaped hub having a surface, an annular shroud, and a plurality of moving blades. The shroud faces the surface of the hub. A plurality of rotor blades are provided in the circumferential direction of the shroud between the hub and the shroud. The bucket is connected to a hub and a shroud. The fan cover is installed outside the shroud in the direction of the rotation axis of the centrifugal impeller so as to include the centrifugal impeller. The fan cover has an opening having a center point on the rotation axis. The electric part rotates the centrifugal impeller. The moving blade includes a first portion located inside the outer peripheral edge of the opening. The first portion has an end surface facing the inner wall of the opening in the fan cover. The shroud includes a second portion that is located on the rotating shaft side and extends in a direction along the rotating shaft. The second portion is disposed so as to face the end surface of the first portion. The inner wall of the opening is located between the end surface and the second portion.

Claims (6)

A centrifugal impeller including a disk-shaped hub having a surface, an annular shroud, and a plurality of moving blades connected to each other;
The shroud faces the surface;
A plurality of the blades are provided in a circumferential direction of the shroud between the hub and the shroud, and are connected to the hub and the shroud.
A fan cover installed outside the shroud in the rotational axis direction of the centrifugal impeller so as to contain the centrifugal impeller,
The fan cover has an opening having a center point on the rotating shaft, and
An electric part for rotating the centrifugal impeller,
The said moving blade is an electric blower containing the 1st part located inside the outer periphery of the said opening part. The first portion has an end surface facing an inner wall of the opening in the fan cover,
In the shroud, the second portion located on the rotating shaft side is disposed to face the end surface of the first portion,
The electric blower according to claim 1, wherein the inner wall of the opening is located between the end surface and the second portion.   The electric blower according to claim 2, wherein the inner wall of the opening extends along the second portion of the shroud.   The electric blower according to any one of claims 1 to 3, wherein the first portion includes an inclined portion that is inclined in a rotation direction of the moving blade with respect to the rotation axis direction. The shroud side portion of the inclined portion has a first inclination angle with respect to the rotation axis direction,
The hub side portion of the inclined portion has a second inclination angle with respect to the rotation axis direction,
The electric blower according to claim 4, wherein the first inclination angle is larger than the second inclination angle. The vacuum cleaner body,
A vacuum cleaner connected to the main body of the vacuum cleaner, and a suction tool for sucking air in the portion to be cleaned;
A dust collection unit provided inside the vacuum cleaner body, communicating with the suction tool, and storing dust of sucked air;
The electric blower according to any one of claims 1 to 5, wherein the electric blower is provided inside the vacuum cleaner main body and sucks air from the suction tool to the dust collecting unit.
A vacuum cleaner provided on the outer side of the main body of the vacuum cleaner, and comprising a discharge port for discharging the air after being collected by the dust collector to the outside of the main body of the vacuum cleaner.

Images