WO2021235197A1

WO2021235197A1 - Electric blower

Info

Publication number: WO2021235197A1
Application number: PCT/JP2021/016756
Authority: WO
Inventors: 静横手
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2020-05-19
Filing date: 2021-04-27
Publication date: 2021-11-25

Abstract

An electric blower (11) is provided with an electric motor (12) including a rotating shaft, an impeller (13) which is fixed to the rotating shaft and which is rotationally driven by the electric motor, and an air guide (14) into which air discharged from the impeller flows, wherein: the impeller includes a rear surface shroud (16), a front surface shroud (17) disposed spaced apart from the rear surface shroud, an intake port (18) provided in a central portion of an upper surface of the front surface shroud, a centrifugal fan (20) consisting of a plurality of first blade portions (19) which are attached to the rear surface shroud and which are arranged at equal intervals in the circumferential direction, and an axial flow fan (22) positioned inward of the centrifugal fan in the radial direction; the centrifugal fan and the axial flow fan rotate in the circumferential direction; and the axial flow fan faces upward in the direction of the rotating shaft, and comprises a plurality of second blade portions (axial flow fan) (21) which are inclined relative to the rotating shaft and which are arranged at equal intervals in the circumferential direction.

Description

Electric blower

This disclosure relates to an electric blower used in various devices including household electric devices.

As a conventional electric blower for a vacuum cleaner, a DC electric blower using a DC motor is used. This type of electric blower is configured to discharge most of the sucked wind to the rear as much as possible. The air sucked by the rotary fan is passed through the inside of the frame and discharged to the outside.

For example, in the conventional electric blowers shown in FIGS. 13 to 15, the electric motor 2 having the rotating shaft 1, the impeller 3 fixed to the rotating shaft 1 and driven to rotate by the electric motor 2, and the air discharged from the impeller 3 are used. It has an inflowing air guide 4, an impeller 3, and a fan case 5 containing the air guide 4. The impeller 3 includes a rear shroud 6, a front shroud 7 spaced apart from the rear shroud 6, an intake port 8 provided in the center of the front shroud 7, and a plurality of wing portions 9 attached to the rear shroud 6. And prepare.

Here, FIG. 13 is a side view of the conventional electric blower, FIG. 14 is a perspective view of the main part of the electric blower, and FIG. 15 is a perspective view showing the impeller 3 of the electric blower. In FIG. 14, the fan case 5 is omitted.

When the impeller 3 rotates, air flows into the fan case 5 from the intake port 8 side. The air that has flowed into the fan case 5 flows between the blades 9. The air extruded between the blades 9 between the two

shrouds

6 and 7 is increased in total pressure by the rotation of the impeller 3 and flows into the air guide 4 formed on the outer peripheral portion of the impeller 3. The air rectified by the air guide 4 is sent into the motor case 10. The air that has passed through the motor case 10 flows out from the exhaust port to the outside of the motor case.

As the prior art document, for example, Patent Document 1 is known.

FIG. 16 is a side view showing the air flow of a conventional electric blower. In the conventional electric blower, as shown in FIG. 16, since the inflowing air is discharged to the outer peripheral side (air guide 4 side) of the impeller 3, the lower part of the central part of the space between the two

shrouds

6 and 7. On the side (rear shroud 6 side), a low-speed basin with slow air flow is created. This has the problem that the fan efficiency may deteriorate.

International Publication No. 2017/104009

This disclosure solves the above problems. It is an object of the present disclosure to provide an electric fan capable of improving fan efficiency.

The electric blower according to the first aspect of the present disclosure includes an electric motor having a rotating shaft, an impeller fixed to the rotating shaft and rotationally driven by the electric motor, and an impeller provided on the outer peripheral portion of the impeller and discharged from the impeller. The impeller is provided with an air guide through which air flows in, and the impeller has a rear shroud, a front shroud arranged at a distance from the rear shroud, an intake port provided in the center of the upper surface of the front shroud, and the rear shroud. A centrifugal fan composed of a plurality of first blades attached to both or one of the front shroud and arranged at equal intervals in the circumferential direction, and an axial flow fan located inside the centrifugal fan in the radial direction. The centrifugal fan and the axial flow fan rotate in the circumferential direction, and the axial flow fan faces upward in the direction of the rotation axis and is inclined with respect to the rotation axis. The two wings are arranged at equal intervals in the circumferential direction.

In the electric blower according to the second aspect of the present disclosure, in the first aspect, the number of blades of the plurality of first blades and the number of blades of the plurality of second blades are equivalent.

In the first or second aspect, the electric blower according to the third aspect of the present disclosure includes the rotational trailing edge portion of the plurality of second wing portions and the rotational direction leading edge portion of the plurality of first wing portions. The angle formed by the wing is in the range of 15 to 40 degrees.

The electric blower according to the fourth aspect of the present disclosure has, in any one of the first to third aspects, the axial direction between the axial upper surface of the impeller facing the air guide and the rear shroud. The dimension of h0, the axial dimension between the rear surface shroud and the rotational trailing edges of the plurality of second blades is t1, and the axial direction between the rear surface shroud and the axial center of the facing portion. When t0 and t1-t0 are h, −20% ≦ h / h0 ≦ 70%.

According to the present disclosure, it is possible to provide an electric blower capable of improving fan efficiency.

Side view of the electric blower according to the embodiment of the present disclosure. An exploded perspective view of the main part of the electric blower Perspective view of the impeller of the electric blower Side view of the impeller of the electric blower The figure which shows the relationship between the number of blades of a plurality of 2nd blades, and the static pressure characteristic when the number of blades of a plurality of 1st blades of the electric blower is 6. The figure which shows the relationship between the number of blades of a plurality of 2nd blades, and the efficiency characteristic when the number of blades of a plurality of 1st blades of the electric blower is 6. Relative velocity vector distribution diagram when the number of blades of the plurality of first blades of the same electric blower is six, and when the number of blades of the plurality of second blades is six. Relative velocity vector distribution diagram when the number of blades of the plurality of first blades of the same electric blower is six and the number of blades of the plurality of second blades is nine. Top view showing the angle between the trailing edge portion in the rotation direction of the plurality of second blade portions and the leading edge portion in the rotation direction of the plurality of first blade portions in the electric blower. The figure which shows the rotation direction trailing edge part, the leading edge part, and the rotation direction leading edge part, the trailing edge part of a plurality of first wing parts in the electric blower. In the same electric blower, the figure which shows the relationship between the rotational position and static pressure characteristic which a plurality of rotation direction trailing edges of a 2nd wing part and the rotation direction leading edge part of a plurality of 1st wing parts form. The figure which shows the relationship between the rotation position and the efficiency characteristic formed by the rotation direction trailing edge part of a plurality of 2nd wing parts, and the rotation direction front edge part of a plurality of 1st wing parts in the electric blower. The figure which shows the flow velocity of the air in the same electric blower when the rotation position formed by the rotation direction trailing edge part of a plurality of 2nd wing parts and the rotation direction front edge part of a plurality of 1st wing parts is 4 degrees. In the same electric blower, the magnitude of the circumferential component of the air flow velocity when the rotation position formed by the rotation direction trailing edges of the plurality of second blades and the rotation direction leading edges of the first blades is 27 degrees. Diagram showing the distribution In the same electric blower, the axial dimension h0 between the axial upper surface L1 of the facing portion between the rear shroud and the air guide of the impeller and the rear shroud, to the rotational trailing edges of the rear shroud and the plurality of second blades. The figure which shows the dimension t1 in the axial direction between, the dimension t0 in the axial direction up to the axial center portion L0 of the rear shroud and the air guide facing portion, and the dimension h obtained by subtracting t0 from t1. The figure which shows the relationship between the height and the static pressure characteristic in the electric blower. The figure which shows the relationship between the height and the efficiency characteristic in the electric blower. Side view of a conventional electric blower Perspective view of the main part of the electric blower Perspective view showing the impeller of the electric blower Side view showing the air flow of the electric blower

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments and examples.

FIG. 1 is a side view of the electric blower according to the embodiment of the present disclosure. FIG. 2 is an exploded perspective view of the main part of the electric blower. FIG. 3 is a perspective view of the impeller of the electric blower.

The electric blower 11 according to the embodiment is located on the outer peripheral portion of the motor 12, the impeller 13 fixed to the rotary shaft RC and rotationally driven by the motor 12, and is discharged from the impeller 13. It includes an air guide 14 into which the air flows in, and a fan case 15 including an impeller 13 and an air guide 14.

The impeller 13 includes a rear shroud 16, a front shroud 17 spaced apart from the rear shroud 16, an intake port 18 provided in the center of the front shroud 17, and / or both of the rear shroud 16 and the front shroud 17. It has a plurality of first wing portions 19 attached to and arranged at equal intervals in the circumferential direction. The centrifugal fan 20 is composed of a plurality of first wing portions 19.

A plurality of first wing portions 19 attached to the rear shroud 16 inside (the radial inside of the centrifugal fan 20), facing upward in the rotation axis RC direction, and inclined with respect to the rotation axis RC. The second wing portions 21 are arranged at equal intervals in the circumferential direction. The axial flow fan 22 is composed of a plurality of second wing portions 21 (omitted in FIG. 2).

Here, the impeller 13 side from the electric motor 12, that is, the direction from the rear shroud 16 to the front shroud 17 is upward in the axial direction, the rotation direction of the impeller 13 is the circumferential direction, and the rotation direction is orthogonal to the circumferential direction toward the rotation axis RC. The direction is sometimes called the radial direction.

The motor 12 is a motor having at least a rotor portion 121, a stator portion 122, and a bracket 123 covering them. The rotor portion 121 is fixed to the rotating shaft RC (shaft 124), and the coil portion 125 is provided. The bracket 123 is formed in a cylindrical shape, and an exhaust port (not shown) is opened below the bracket 123. The impeller 13 is rotatably connected to the rotary shaft RC.

The fan case 15 (omitted in FIG. 2) has a cylindrical shape and is attached to the upper part of the bracket 123. Inside the fan case 15, an impeller 13 and an air guide 14 facing the impeller 13 and forming a space through which the air discharged from the impeller 13 flows are housed.

The impeller 13 includes a rear shroud 16, a front shroud 17 spaced apart from the rear shroud 16, an intake port 18 provided in the center of the front shroud 17, and / or both of the rear shroud 16 and the front shroud 17. A plurality of first wing portions 19 (centrifugal fan 20) and a plurality of second wing portions 21 (axial flow fan 22) attached to the above are provided.

The rear shroud 16 has a disk shape. The front shroud 17 has a ring shape with a curved cross section. An intake port 18 is provided at the radial center portion of the surface (upper surface) of the front shroud 17 that does not face the rear shroud. The rear shroud 16 and the front shroud 17 are arranged coaxially. The rear shroud 16 and the front shroud 17 are made of, for example, resin or sheet metal. The rear shroud 16 and the front shroud 17 are arranged at regular intervals. The upper surface refers to a surface that is higher in the axial direction, and the same applies to the following description.

The plurality of first wing portions 19 (centrifugal fans 20) are integrally molded with the rear shroud 16 or the front shroud 17, for example, made of resin or sheet metal. The plurality of first wing portions 19 are formed so as to extend radially around the rotation axis RC. The plurality of first wing portions 19 are formed so as to stand up from the rear shroud 16 in the direction of the rotation axis RC. Further, for example, the rear tilting blade shape is inclined toward the reverse side toward the outer periphery of the rear surface shroud 16 in the rotation direction (counterclockwise in the drawing).

The plurality of wings of the first wing portion 19 are provided at equal intervals in the circumferential direction. The number of the plurality of first wing portions 19 is, for example, six.

A plurality of second wing portions 21 (axial flow fans 22) are attached to the radial center portion of the upper surface of the rear shroud 16. The plurality of second wing portions 21 are made of, for example, resin or sheet metal. The plurality of second wing portions 21 are arranged inside the plurality of first wing portions 19 (centrifugal fan 20) in the radial direction.

The plurality of second wing portions 21 are oriented upward in the rotation axis RC direction, and are inclined with respect to the rotation axis RC so that the leading edge in the rotation direction is located above the trailing edge. ..

The blades of the plurality of second wing portions 21 are provided at equal intervals in the circumferential direction. The number of the plurality of second wing portions 21 is, for example, six.

The centrifugal fan 20 and the axial fan 22 are separate bodies, and both are fixed to the rotating shaft RC. Therefore, it rotates synchronously. If the axial flow fan 22 is formed of sheet metal, it is easy to manufacture.

The centrifugal fan 20 and the axial flow fan 22 may be integrally formed with the rear shroud 16, or may be formed separately and then attached to the rear shroud 16.

In the electric blower 11 in the above embodiment, when the impeller 13 is rotated by the electric motor 12, air is made to flow into the fan case 15 from the intake port 18 side. The air that has flowed into the fan case 15 from the radial outside of the intake port 18 flows between the blade portions of the plurality of first blade portions 19. The total pressure of the air extruded between each wing portion of the first wing portion 19 between the rear surface shroud 16 and the front shroud 17 is increased by the rotation of the impeller 13, and the air guide 14 formed on the outer peripheral portion of the impeller 13 is formed. Inflow to.

Further, the air that has flowed into the fan case 15 from the radial center side of the intake port 18 flows between the blade portions of the plurality of second blade portions 21. The total pressure of the air extruded between the wing portions of the second wing portion 21 is increased by the rotation of the impeller 13, and flows into the air guide 14 through the wing portions of the plurality of first wing portions 19.

The air rectified by the air guide 14 is sent into the bracket 123 of the motor 12. The air that has passed through the bracket 123 flows out of the bracket 123 from the exhaust port (not shown).

The electric blower 11 is provided with an axial flow fan 22 at the radial center of the space between the rear shroud 16 and the front shroud 17. Therefore, as shown in FIG. 4, a plurality of centrifugal fans 20 are used at high speed without causing a low-speed basin in which the flow is slow even for the air flowing into the fan case 15 from the radial center side of the intake port 18. It can be drained between the wing portions of the first wing portion 19 of the above. FIG. 4 is a side view of the impeller of the electric blower according to the embodiment of the present disclosure. Therefore, air can be discharged to the outer peripheral side (air guide 14) by the centrifugal fan 20. This can be expected to have the effect of improving fan efficiency.

In the embodiment of the present disclosure, the number of blades of the plurality of first wing portions 19 and the number of blades of the plurality of second wing portions 21 are 6 and are equivalent.

FIG. 5A shows the relationship between the number of blades of the plurality of second blade portions 21 and the static pressure characteristic when the number of blades of the plurality of first blade portions 19 of the electric blower according to the embodiment of the present disclosure is six. It is a figure. FIG. 5B is a diagram showing the relationship between the number of blades of the plurality of second blade portions 21 and the efficiency characteristics when the number of blades of the plurality of first blade portions 19 of the electric blower is six.

As is clear from FIGS. 5A and 5B, when the number of blades of the plurality of second blade portions 21 is 6, that is, the number of blades is the same as the number of blades of the plurality of first blade portions 19, the static pressure characteristic and the efficiency characteristic are the most. It can be seen that the fan efficiency is good, the loss is small, and the fan efficiency is good.

FIG. 6A shows a relative velocity vector when the number of blades of the plurality of first blade portions 19 of the electric blower according to the embodiment of the present disclosure is six, and when the number of blades of the plurality of second blade portions 21 is six. It is a distribution (cross section perpendicular to the rotation axis RC) diagram. FIG. 6B is a relative velocity vector distribution diagram when the number of blades of the plurality of first blade portions 19 of the electric blower is six and the number of blades of the plurality of second blade portions 21 is nine.

When the number of blades of the plurality of second blade portions 21 is 9, as shown in FIG. 6B, the inflow of air into the plurality of first blade portions 19 is different for each blade, so that the blade of the first blade portion 19 is used. Of these, there are wings with large losses (points indicated by arrows).

FIG. 7 shows an angle formed by the rotation direction trailing edge portion 21a of the plurality of second wing portions 21 and the rotation direction leading edge portion 19a of the plurality of first wing portions 19 in the electric blower according to the embodiment of the present disclosure. It is a top view which shows. The angle θ is in the range of 15 to 40 degrees.

FIG. 8 shows, in the electric blower according to the embodiment of the present disclosure, the rotation direction trailing edge portion and the leading edge portion of the plurality of second wing portions 21, and the rotation direction leading edge portion and the trailing edge portion of the plurality of first wing portions 19. It is a figure which shows the part. As shown in FIG. 8, the rotation direction leading edge portion 19a of the first wing portion 19 refers to the frontmost portion in the rotation direction of the first wing portion 19. The trailing edge portion 21a in the rotation direction of the second wing portion 21 refers to the rearmost portion of the second wing portion 21 in the rotation direction. The trailing edge portion 19b in the rotation direction of the first wing portion 19 refers to the rearmost portion of the first wing portion 19 in the rotation direction. The leading edge portion 21b in the rotation direction of the second wing portion 21 refers to the frontmost portion in the rotation direction of the second wing portion 21. The trailing edge portion 21a in the rotation direction of the second wing portion 21 is located below the leading edge portion 21b in the rotation direction of the second wing portion 21 in the axial direction.

FIG. 9A shows an angle θ formed by the rotational trailing edge 21a of the plurality of second wing portions 21 and the rotational leading edge 19a of the first wing 19 in the electric blower according to the embodiment of the present disclosure. It is a figure which shows the relationship between static pressure characteristic and static pressure characteristic. FIG. 9B shows the relationship between the rotational position and the efficiency characteristic formed by the rotational trailing edge 21a of the plurality of second wing portions 21 and the rotational leading edge 19a of the first wing 19 in the electric blower. It is a figure which shows.

As is clear from FIGS. 9A and 9B, when the angle θ is in the range of 15 to 40 degrees, the improvement rate of static pressure or efficiency is 1% or more (static pressure difference of 150 Pa corresponds to 1% improvement). It can be seen that the loss is small and the fan efficiency is good.

That is, the axial flow fan 22 and the centrifugal fan 20 are set to the optimum relative positions so that the main flow (high speed flow) of the axial flow fan 22 flows into the centrifugal fan 20 at a position where the loss is low.

FIG. 10A shows an angle θ formed by the rotational trailing edge 21a of the plurality of second wing portions 21 and the rotational leading edge 19a of the first wing 19 in the electric blower according to the embodiment of the present disclosure. It is a figure which shows the magnitude distribution (cross section perpendicular to the rotation axis RC) of the circumferential component of the air flow velocity when is 4 degrees. FIG. 10B shows the air when the angle θ formed by the rotational trailing edge 21a of the plurality of second wing portions 21 and the rotational leading edge 19a of the first wing 19 in the electric blower is 27 degrees. It is a figure which shows the size distribution of the circumferential component of the flow velocity of. When the angle θ is 27 degrees, the circumferential component of the flow velocity is larger and the output is larger.

Since the first wing portion 19 and the second wing portion 21 rotate in synchronization with each other, this angle θ does not change.

FIG. 11 shows, in the electric blower according to the embodiment of the present disclosure, a portion facing the air guide 14 of the impeller 13 (air guide facing portion) 14a (located radially outside the impeller 13 and an outlet portion of the centrifugal fan 20). ) Axial dimension h0 between the axial upper surface L1 and the rear surface shroud 16, axial dimension t1 between the rear surface shroud 16 and the rotational trailing edge 21a of the plurality of second wing portions 21, and the rear surface. It is a figure which shows the dimension h which subtracted t0 from the dimension t0 and t1 in the axial direction up to the axial center portion L0 of the shroud 16 and the air guide facing portion 14a. At this time, −20% ≦ h / h0 ≦ 70%.

FIG. 12A is a diagram showing the relationship between the height (%) and the static pressure characteristic in the electric blower according to the embodiment of the present disclosure. FIG. 12B is a diagram showing the relationship between the height (%) and the efficiency characteristics in the electric blower.

As is clear from FIG. 12, when -20% ≤ h / h0 ≤ 70%, the improvement rate of static pressure or efficiency is 1% or more (static pressure difference of 150 Pa corresponds to 1% improvement), the loss is small, and the fan efficiency is small. Turns out to be good.

That is, the trailing edge portion 21a of the axial flow fan 22 may be arranged at a position facing the center portion L0 of the outlet height of the centrifugal fan 20 (the portion facing the air guide 14 14a). Since the wing portion has a large amount of work at the trailing edge, the trailing edge portion 21a of the axial flow fan 22 is arranged at a position facing the axial height center of the trailing edge portion 19b of the centrifugal fan 20, and the axial flow fan 22 is arranged. Prevents a decrease in the work load at the lower portion of the trailing edge portion 21a.

As described above, the electric blower 11 according to the embodiment of the present disclosure includes an electric motor 12 having a rotary shaft RC, an impeller 13 fixed to the rotary shaft RC and rotationally driven by the motor 12, and an outer peripheral portion of the impeller 13. The impeller 13 is provided with an air guide 14 from which the air discharged from the impeller 13 flows in, and the impeller 13 includes a rear shroud 16, a front shroud 17 arranged at a distance from the rear shroud 16, and the center of the upper surface of the front shroud 17. An intake port 18 provided in the portion, a centrifugal fan 20 composed of a plurality of first wing portions 19 attached to both or one of the rear shroud 16 and the front shroud 17 and arranged at equal intervals in the circumferential direction, and a centrifugal fan 20. It has an axial flow fan 22 located inside the centrifugal fan 20 in the radial direction, the centrifugal fan 20 and the axial flow fan 22 rotate in the circumferential direction, and the axial flow fan 22 faces upward in the direction of the rotating shaft RC. A plurality of second wing portions 21 which are inclined with respect to the rotation axis RC are arranged at equal intervals in the circumferential direction.

This makes it possible to provide an electric fan that can improve fan efficiency.

Further, it is preferable that the number of blades of the plurality of first blade portions 19 and the number of blades of the plurality of second blade portions 21 are the same.

Further, it is preferable that the angle formed by the trailing edge portion 21a in the rotation direction of the plurality of second wing portions 21 and the leading edge portion 19a in the rotation direction of the plurality of first wing portions 19 is within the range of 15 degrees to 40 degrees.

Further, the axial dimension between the axial upper surface of the impeller 13 facing the air guide 14 (air guide facing portion) and the rear surface shroud 16 is h0, and the rotation of the rear surface shroud 16 and the plurality of second wing portions 21. When the axial dimension between the directional trailing edge 21a is t1, the axial dimension between the rear shroud 16 and the axial center of the air guide facing portion is t0, and t1-t0 is h. It is preferably −20% ≦ h / h0 ≦ 70%.

Note that the above embodiment is only an example, and the present invention is not limited to this and can be appropriately modified.

The electric blower according to the present disclosure can be widely used for electric blowers and the like used in various devices including household electric devices.

11 Electric blower 12 Motor 13 Impeller 14 Air guide 15 Fan case 16 Rear shroud 17 Front shroud 18 Intake port 19 1st wing 20 Centrifugal fan 21 2nd wing 22 Axial flow fan 121 Rotor 122 Stator 123 Bracket 124 Shaft 125 Coil part

Claims

An electric motor with a rotating shaft and
An impeller fixed to the rotating shaft and driven to rotate by the motor,
An air guide provided on the outer peripheral portion of the impeller and into which the air discharged from the impeller flows is provided.
The impeller is
With the rear shroud,
The front shroud, which is spaced apart from the rear shroud,
An intake port provided in the center of the upper surface of the front shroud that does not face the rear shroud,
A centrifugal fan composed of a plurality of first blades attached to the rear shroud and / or one of the front shroud and arranged at equal intervals in the circumferential direction.
It has an axial fan located inside the centrifugal fan in the radial direction.
The centrifugal fan and the axial flow fan rotate in the circumferential direction, and the centrifugal fan and the axial flow fan rotate in the circumferential direction.
The axial flow fan faces upward from the rear surface shroud toward the front shroud in the direction of the rotation axis, and a plurality of second blade portions inclined with respect to the rotation axis are arranged at equal intervals in the circumferential direction. The electric blower that has been.
The electric blower according to claim 1, wherein the number of blades of the plurality of first blade portions is equal to the number of blades of the plurality of second blade portions.
The invention according to claim 1 or 2, wherein the angle formed by the rotational trailing edge portion of the plurality of second wing portions and the rotational leading edge portion of the plurality of first wing portions is in the range of 15 degrees to 40 degrees. Electric blower.
The axial dimension between the axial upper surface of the impeller facing the air guide and the rear surface shroud facing the rear surface shroud is h0, and the rotational direction of the rear surface shroud and the plurality of second wing portions. -20% ≦ when the axial dimension to the trailing edge is t1, the axial dimension to the axial center of the rear surface shroud and the facing portion is t0, and t1-t0 is h. The electric blower according to any one of claims 1 to 3, wherein h / h0 ≦ 70%.