JP6695419B2 - Electric blower and vacuum cleaner - Google Patents

Description

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

  Conventionally, an electric blower used for an electric vacuum cleaner is known. The electric blower rotates an annular shroud, a hub arranged to face the shroud, a plurality of rotor blades arranged in the circumferential direction between the shroud and the hub, and the shroud, the hub and the rotor blade. And a centrifugal impeller. In such an electric blower, in order to improve the efficiency, in the gap between the centrifugal impeller inlet and the fan cover that contains the centrifugal impeller, the airflow that has flowed out from the centrifugal impeller outlet does not re-enter the centrifugal impeller inlet, There is a device provided with a leak prevention means (see, for example, FIGS. 1 to 3 of JP 2013-60839 A (Patent Document 1) and JP 2000-154797 A).

JP, 2013-60839, A Japanese Patent Laid-Open No. 2000-154797

  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 prevention unit 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 rub against each other, and the seal member wears. As a result, the leak prevention effect of the seal member is reduced. When the leak prevention effect is reduced, the circulation flow of the air flow that has flowed out from the centrifugal impeller outlet increases again as it flows back from the centrifugal impeller inlet. When such a circulating flow increases, there is a problem that the load applied to the moving blades increases and the efficiency decreases.

  Also, as disclosed in Japanese Patent Laid-Open No. 2000-154797, when a groove is provided on the inner peripheral side end surface of the shroud and the inner peripheral side end portion of the fan cover is fitted into this groove, the structure may be adopted. is there. However, even with such a configuration, the air flow that re-enters from the seal structure to the inlet of the centrifugal impeller is mixed with the main flow of air sucked from the inlet of the stretching impeller. When such a re-inflow airflow mixes with the main flow at the inlet of the centrifugal impeller, there is a problem in that collision loss at the leading edge of the moving blade increases and efficiency also decreases.

  The present invention has been made to solve the above problems, and an object of the present invention is to obtain a highly efficient electric blower and an electric vacuum cleaner equipped with the electric blower.

The electric blower which concerns on this invention is equipped with 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 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 blades are connected to the hub and shroud. The fan cover is installed outside the shroud in the rotational axis direction 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 rotor 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 located on the rotation axis side and extending in a direction along the rotation axis. The second portion is arranged 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.

  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 flow direction of the air in the moving blade. The gap between the inner wall of the opening of the fan cover and the shroud serves as a flow path of air (circulation flow) that re-enters 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 circulation flow flows into the upstream side of the first portion of the blade, the main flow and the circulation flow are mixed with each other to generate a complicated air flow. As a result, the load on the blade is increased and the efficiency is increased. It is possible to suppress the occurrence of the problem that As a result, a highly efficient electric blower can be realized. Furthermore, by mounting this electric blower, a highly efficient electric vacuum cleaner can be obtained.

It is a schematic diagram of the electric vacuum cleaner which shows embodiment of this invention. It is a cross-sectional schematic diagram of the vertical direction of the electric blower in embodiment of this invention. It is a cross-sectional schematic diagram of the vertical direction which shows some electric blowers in an embodiment of the invention. It is a perspective schematic diagram of the centrifugal impeller in embodiment of this invention. FIG. 3 is a schematic vertical sectional view showing a part of a moving blade of the centrifugal impeller according to the embodiment of the present invention. It is a cross-sectional schematic diagram of the vertical 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 designated by the same reference numerals, and the description thereof will not be repeated.

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

  The dust collector 5 is provided inside the electric vacuum cleaner body 1, communicates with the suction tool 4, and stores dust of the sucked air. The electric blower 6 is provided inside the electric vacuum cleaner body 1 and sucks air from the suction tool 4 to the dust collecting portion 5. The electric blower 6 is an electric blower according to an embodiment of the present invention described later. The exhaust port 7 is provided on the outside of the electric vacuum cleaner body 1 and discharges the air, which has been collected by the dust collecting portion 5, to the outside of the electric vacuum cleaner body 1. The discharge port 7 is provided at the rear of the vacuum cleaner body 1 as shown in FIG.

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

<Structure of electric blower according to the present embodiment>
FIG. 2 is a schematic vertical cross-sectional view of the electric blower according to the embodiment of the present invention. In FIG. 2, arrows indicate the flow of air. FIG. 3 is a schematic vertical sectional view showing a part of the electric blower shown in FIG. 2. FIG. 4 is a schematic perspective view of a centrifugal impeller that constitutes the electric blower shown in FIG. 2. FIG. 5 is a schematic vertical cross-sectional view showing a part of the moving blades of the centrifugal impeller according to 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 section 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 rotor blades 25 are provided in the circumferential direction of shroud 24 between hub 23 and shroud 24. The 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 part 9 rotates the centrifugal impeller 11. The electric section 9 is arranged inside the electric blower 6. The electric section 9 includes a shaft 10. The centrifugal impeller 11 is fixed to the shaft 10. The electric motor 9 rotates the shaft 10 to rotate the centrifugal impeller 11. The electric section 9 is an electric motor such as a motor.

  A diffuser 15 is arranged between the electric section 9 and the centrifugal impeller 11. The diffuser 15 includes a plurality of vanes 12, a plurality of return vanes 13, and a main plate 14. The plurality of stationary blades 12 are arranged on the outer peripheral side of the centrifugal impeller 11. The return vane 13 is arranged 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 return stationary blade 13 to each other.

  The fan cover 16 is provided above the centrifugal impeller 11 as described above. The fan cover 16 includes the centrifugal impeller 11 and the vanes 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 edge if the outer edge of the bell mouth 18 has a circular planar shape. When the outer peripheral edge of the bell mouth 18 has 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 means not only the case where the rotation axis and the center point overlap, but also the case where the center point is included in a cylindrical region having a radius of 5 mm centering on the rotation axis. 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 on the outer peripheral side of the vane 12 as a gas flow path from the vane 12 to the return vane 13 side.

  The rotor blades 25 of the centrifugal impeller 11 include 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 of the fan cover 16. In the shroud 24, the second portion 34 located on the rotation axis side is arranged so as to face the end surface 36A of the first portion 36. The second portion 34 is formed to extend in the direction along the rotation axis indicated by the alternate long and short dash line located at the right end of FIG. In the shroud 24, the second portion 34 has an annular plane shape as shown in FIG. The inner wall of the bell mouth 18 is located between the end surface 36A and the second portion 34. From a different point of view, the region sandwiched by the end surface 36A of the first portion 36 of the rotor blade 25 and the second portion 34 of the shroud 24 constitutes the groove 35. The inner wall of the bell mouth 18 is located inside the groove 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 surface 36A of the first portion 36. The position of the top surface 36B of the first portion 36 is located farther from the lower end 18A 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 inside the outer peripheral edge of the bell mouth 18 of the fan cover 16 and extends above 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 with respect to the rotation axis direction in the rotation direction R of the moving blade 25 by an inclination angle θ. Here, the inclination angle θ refers to an angle formed by the rotation axis direction of the centrifugal impeller 11 and a line segment passing through the central portion of the inclined portion 26 in the thickness direction. The broken line arrow R in FIG. 4 indicates the rotation direction R of the moving blade 25.

  On the side surface of the electric blower 6, a bracket 19 which is connected to the fan cover 16 and encloses the return vanes 13 is arranged. Further, on the side surface of the electric blower 6, a motor frame 20 that is connected to the bracket 19 and encloses the electric section 9 is provided. The motor frame 20 is provided with several discharge holes 22 for discharging the air that has passed through the centrifugal impeller 11, the diffuser 15, and the motorized portion 9.

<Effects of electric blower>
2 to 5, the bell mouth 18 serving as the 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 moving blade 25. The inner wall of is located. The 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) that re-enters from the centrifugal impeller outlet to the centrifugal impeller inlet as shown by an arrow 41 in FIG. Is becoming Therefore, the circulating flow flows into the centrifugal impeller from the downstream side of the first portion 36 of the moving blade 25. Therefore, when the circulation flow flows into the upstream side of the first portion 36 of the moving blade 25, the main flow indicated by the arrow 42 in FIG. 3 and the circulation flow are mixed to generate a complicated air flow. Can be prevented. Therefore, as compared with the case where such a complicated air flow occurs on the upstream side of the moving blade 25, the collision loss at the leading edge (the edge portion of the first portion 36) of the moving blade 25 can be reduced. As a result, the load on the moving blade 25 can be reduced, and the highly efficient electric blower 6 can be realized. Further, by mounting the electric blower 6, a highly efficient electric vacuum cleaner can be obtained.

  Further, in the electric blower 6 described above, the first portion 36 has the end surface 36 </ b> A that faces the inner wall of the bell mouth 18 of the fan cover 16. In the shroud 24, the second portion 34 located on the rotation axis side is arranged so as to face the end surface 36A of the first portion 36. The inner wall of the bell mouth 18 is located between the end surface 36A and the second portion 34. With such a configuration, the path through which the circulation flow flows into the centrifugal impeller is set to 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. Therefore, by setting the distance between the second portion 34 and the inner wall of the bell mouth 18 to be sufficiently small, the inflow amount of the circulation flow can be reduced. For example, the distance can be 0.1 mm or more and 0.3 mm or less. By doing so, the load applied to the moving 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 circulation 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 set to 1 mm or more and 5 mm or less, more preferably 2 mm or more and 4 mm or less. You can

  Further, 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 moving 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 relative velocity of the moving blade inlet (a combination of the peripheral velocity of the moving blade and the absolute velocity 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 electric vacuum cleaner will be described.

  In the electric vacuum cleaner configured as described above, when the electric power is supplied to the electric section 9, the shaft 10 rotates. When the shaft 10 rotates, the centrifugal impeller 11 attached to the shaft 10 rotates and sucks air from the suction port 17. As a result, 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 which are connected to the vacuum cleaner body 1. The air sucked by the vacuum cleaner body 1 is collected in the dust collecting section 5. After that, the air discharged from the dust collecting portion 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 by the centrifugal impeller 11 is pressurized and accelerated by the centrifugal impeller 11 and heads radially outward while turning. A 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 pressurized between the vanes of the vanes 12 of the diffuser 15. After that, the air passes through the gap 21 between the diffuser 15 and the fan cover 16. Further, the air is guided to the electric power unit 9 side by the return vanes 13 and cools the electric power unit 9. After that, the air is discharged to the outside of the electric blower from the discharge hole 22 provided in the motor frame 20. Then, air is discharged to the outside of the electric vacuum cleaner body 1 from the exhaust port 7 provided in the vacuum cleaner body 1.

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

<Structure and operation effect of modified example of electric blower>
FIG. 6 is a vertical cross-sectional schematic diagram of the moving blade 25 in the modification of the embodiment of the present invention. The electric blower including the moving blade 25 shown in FIG. 6 has basically 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, a portion 26C of the inclined portion 26 on the shroud 24 (see FIG. 3) side has a first inclination angle θ1 with respect to the rotation axis direction. A portion 26B of the inclined portion 26, which is closer to the hub 23 than the above portion 26C, has a second inclination angle θ2 with respect to the rotation axis direction. The first tilt angle θ1 is larger than the second tilt 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 tilt angle is 0 °, for example. Therefore, the first tilt angle θ1 is larger than the third tilt angle. The second tilt angle θ2 is also larger than the third tilt angle. It should be noted that the third inclination angle can be selected to any value as long as it is smaller than the first and second inclination angles.

  By providing such a configuration, similarly to the electric blower shown in FIGS. 1 to 5, the load applied to the moving blade 25 can be effectively reduced.

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

  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 rather the shape and the 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. Therefore, the effect of reducing the load on the moving blade 25 due to deterioration over time is small, and the performance can be maintained for a long time.

  The electric blower as described above is not limited to household or commercial electric vacuum cleaners, 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 embodiments of the present invention have been described above, the above-described embodiments can be variously modified. Further, the scope of the present invention is not limited to the above embodiment. The scope of the present invention is shown by the claims and is intended to include meanings equivalent to the claims and all modifications within the scope.

  INDUSTRIAL APPLICABILITY The present invention can be advantageously applied to appliances using electric blowers, such as household and commercial vacuum cleaners and hand dryers.

  1 vacuum cleaner 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 vanes, 13 return vanes, 14 main plate, 15 diffuser, 16 fan cover, 17 suction port, 18 bell mouth, 18A lower end, 19 bracket, 20 motor frame, 21 gap, 22 discharge hole, 23 hub, 24 shroud, 25 moving blade, 26 inclined portion, 26A to 26C portion, 34 second portion, 35 groove portion, 36 first portion, 36A end surface, 36B top surface, 41, 42 arrows.

Claims (4)

A centrifugal impeller including a disk-shaped hub having a surface, an annular shroud, and a plurality of blades connected to each other,
The shroud faces the surface,
A plurality of the moving blades are provided in the circumferential direction of the shroud between the hub and the shroud, are connected to the hub and the shroud, and
A fan cover installed outside the shroud in the rotational axis direction 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, and
An electric part for rotating the centrifugal impeller,
The rotor blade includes a first portion located inside an outer peripheral edge of the opening,
The first portion has an end surface facing the inner wall of the opening of the fan cover,
The shroud includes a second portion located on the rotation axis side and extending in a direction along the rotation axis,
The second portion is arranged 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,
The inner wall of the opening extends along the second portion of the shroud and is further connected to a top wall of the fan cover,
The inner wall of the opening portion has an end portion of the second portion facing the top wall of the fan cover, and an end portion of the second portion that faces the top wall of the fan cover from a length of a portion overlapping the second portion in a direction along the rotation axis . An electric blower in which the length of the line extending from the end of the two portions in the direction along the rotation axis and the intersection of the top wall on the side of the second portion of the fan cover is longer.   The electric blower according to claim 1, 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. In the inclined portion, the shroud side portion has a first inclination angle with respect to the rotation axis direction,
In the inclined portion, the hub-side portion has a second inclination angle with respect to the rotation axis direction,
The electric blower according to claim 2, wherein the first inclination angle is larger than the second inclination angle. With the vacuum cleaner body,
A suction tool that is connected to the electric vacuum cleaner body by a pipe line and sucks air in the portion to be cleaned,
A dust collecting portion that is provided inside the electric vacuum cleaner body, communicates with the suction tool, and stores dust of sucked air;
The electric blower according to claim 1, wherein the electric blower is provided inside the electric vacuum cleaner body, and sucks air from the suction tool to the dust collecting section.
An electric vacuum cleaner, comprising: an outlet provided outside the electric vacuum cleaner main body, for discharging air after being collected by the dust collecting unit to the outside of the electric vacuum cleaner main body.

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