WO2023286293A1

WO2023286293A1 - Electric blower, and electric vacuum cleaner provided with same

Info

Publication number: WO2023286293A1
Application number: PCT/JP2022/000839
Authority: WO
Inventors: 武史本多; 誠二坂上; 啓祐竹内; 賢宏伊藤; 将太山上; 孔陽川本; 聡菊地; 真一湧井
Original assignee: 日立グローバルライフソリューションズ株式会社
Priority date: 2021-07-14
Filing date: 2022-01-13
Publication date: 2023-01-19
Also published as: TWI843058B; TW202302025A; JP7663441B2; JP2023012650A; JP2025098249A; CN117597522A

Abstract

In the present invention, a motor unit has a rotational shaft, a bearing, a rotor core, a stator core, and a motor housing having an upstream-side radial opening and a downstream-side radial opening formed in the lateral surface thereof. A blower unit has an impeller fixed to the distal end of the rotational shaft, a fan casing covering the periphery of the impeller, an upstream-side housing surrounding the upstream-side periphery of the motor unit, and a downstream-side housing surrounding the downstream-side periphery of the motor unit. A first flow path passes between an inner wall and an outer wall of the upstream-side housing and between an inner wall and an outer wall of the downstream side housing. A second flow path passes through the downstream-side radial opening or a rotational axis-direction opening in the downstream-side motor housing, through the interior of the motor unit, through the upstream-side radial opening, between the motor housing and the inner wall of the upstream-side housing, and between the motor housing and the inner wall of the downstream-side housing. On the downstream side of the downstream-side housing, an annular diffuser facing the downstream-side radial opening is provided.

Description

Electric blower and vacuum cleaner equipped with the same

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

As an example of an electric blower (blower device) built into a vacuum cleaner, Patent Document 1 describes "an impeller having an impeller 10 rotating around a vertically extending central axis C and a stator 24 disposed below the impeller. , a motor housing 21 that houses the stator, and a fan casing 2 that houses the impeller and the motor housing and forms the first flow path 5 in the gap between the motor housing and the upper part of the fan casing. covers the top of the impeller and has an intake port 3 that opens vertically, and an exhaust port 4 that communicates with the intake port via a first flow path is provided in the lower part of the fan casing. Below the upper surface of the stator fixed to the inner surface of the housing, an inlet 21a penetrating in the radial direction and communicating with the first flow path is provided, and the motor housing extends upward from the inlet and is above the stator. A blower device having a second flow path 6 communicating with the space of .

JP 2018-105269 A

It is known that the operating air volume of electric vacuum cleaners varies greatly depending on operating conditions such as filter clogging due to dust and the material of the floor to be cleaned. Therefore, as an electric blower for vacuum cleaners, an electric blower with a strong suction force over a wide air volume range is desired.

In addition, due to the ease of use of electric vacuum cleaners, electric blowers are also required to be smaller and lighter. It is necessary to improve the cooling performance of

In particular, vacuum cleaners driven by batteries (secondary batteries) such as cordless stick vacuum cleaners and autonomous driving vacuum cleaners (robot vacuum cleaners) consume less power due to the battery capacity, and the maximum air flow is also low. small. Therefore, when the filter is clogged, there is a problem that the dust carrying capacity is lowered and the suction power of the vacuum cleaner is lowered. Furthermore, battery-powered vacuum cleaners are required to be compact and lightweight, and electric blowers mounted on vacuum cleaners are required to have both a strong suction force over a wide air volume range and a small size.

Here, if a diffuser blade ("stationary blade 40" in Patent Document 1) is used, excellent pressure recovery can be performed at the design point air volume, but the air volume is lower than the design point air volume due to filter clogging and the like. If so, the mismatch between the entrance angle of the diffuser blades and the angle of entry of the airflow into the diffuser can degrade diffuser performance and reduce the suction power of the vacuum cleaner.

Further, in the air blower of Patent Document 1, as shown in FIG. 4 and the like of the same document, part of the airflow S flowing through the outer first flow path 5 flows into the inlet 21a provided in the peripheral wall of the motor housing 21. , flows into the inner second flow path 6, cools the upper bearing 26, further cools the lower bearing 26, and flows into the second flow path 6 without joining the first flow path 5. The air is exhausted to the outside of the blower 1 from the outlet (outflow port 29a). Thus, when adopting a configuration in which the second flow path 6 branched from the first flow path 5 does not join the first flow path 5 , part of the airflow S flowing through the first flow path 5 is In the first flow path 5, the air volume downstream of the inflow port 21a (branch point) is smaller than the air volume upstream of the inflow port 21a (branch point) due to the pressure loss (resistance) at the time of branching. rice field.

In addition, since the second flow passage 6 of Patent Document 1 is small, the flow passage area is small. There is concern that the temperature inside the motor 20 will rise and the motor efficiency will decrease.

The present invention is intended to solve the above problems, and is an electric blower that is compact and lightweight, has high efficiency in a wide air volume range, and has high motor cooling efficiency, and a vacuum cleaner equipped with the same. for the purpose of providing

In order to solve the above-mentioned problems, an electric blower according to the present invention is an electric blower in which a first flow path circulates inside a blower section and a second flow path circulates inside a motor section, wherein the motor section rotates a shaft, a bearing that rotatably supports the rotating shaft, a rotor core fixed to the rotating shaft, a stator core that surrounds the outer periphery of the rotor core, a stator core that holds the stator core, and an upstream radial direction on the side surface. An opening and a motor housing having a downstream radial opening are provided, and the blower section includes an impeller fixed to the tip of the rotating shaft, a fan casing covering the outer circumference of the impeller, and the motor section. and a downstream housing surrounding the downstream outer periphery of the motor section, wherein the first flow path extends between the inner wall and the outer wall of the upstream housing and the downstream Circulating between the inner wall and the outer wall of the side housing, the second flow path extends from the downstream side radial opening to the rotation axis direction opening of the downstream side motor housing, the inside of the motor section, the upstream side radial opening, Circulates between the inner wall of the motor housing and the upstream housing and between the inner wall of the motor housing and the downstream housing, and faces the downstream radial opening on the downstream side of the downstream housing. An electric blower with an annular diffuser was used.

ADVANTAGE OF THE INVENTION According to the present invention, it is possible to provide an electric blower that is compact and lightweight, has high efficiency in a wide air volume range, and has a high motor cooling efficiency, and a vacuum cleaner equipped with the electric blower. .

The external view of the electric blower of one Example. 1 is a longitudinal sectional view of an electric blower of one embodiment; FIG. The perspective view of the impeller of one Example. FIG. 1 is a longitudinal sectional view of an impeller of one embodiment; FIG. 4 is a plan view of the upstream housing of one embodiment; FIG. 4 is a vertical cross-sectional view of the upstream housing of one embodiment; FIG. 4 is a partial cross-sectional view of the upstream housing of one embodiment; FIG. 4 is a plan view of the downstream housing of one embodiment; FIG. 4 is a vertical cross-sectional view of the downstream side housing of one embodiment; FIG. 4 is a partial cross-sectional perspective view of an example downstream housing. FIG. 2 is an external view of a motor section of one embodiment; FIG. 2 is a vertical cross-sectional view of the motor portion of one embodiment; FIG. 4 is a longitudinal sectional view showing an example of the structure of the second channel; FIG. 4 is a longitudinal sectional view showing an example of the structure of the second channel; FIG. 4 is a longitudinal sectional view showing an example of the structure of the second channel; 1 is a perspective view of an electric vacuum cleaner of one embodiment; FIG. 1 is a longitudinal sectional view of an electric vacuum cleaner of one embodiment; FIG. 4 is a graph comparing blower efficiencies of electric blowers of an example and a comparative example. 4 is a graph comparing temperature rises of electric blowers of an example and a comparative example.

　Hereinafter, an electric blower of the present invention and an electric vacuum cleaner equipped with the same will be described in detail with reference to the drawings.

<Schematic configuration of electric vacuum cleaner 100>
First, a vacuum cleaner 100 according to an embodiment of the present invention will be described with reference to FIGS. 7 and 8. FIG. 7 is a perspective view of vacuum cleaner 100, and FIG. 8 is a longitudinal sectional view of vacuum cleaner 100. As shown in FIG. The illustrated electric vacuum cleaner 100 is a rechargeable cordless stick vacuum cleaner in which a cleaner main body 110 is attached to a holding portion 120, and can be charged while placed on a charging base 130. FIG. Although a rechargeable cordless stick cleaner is exemplified here, the electric blower 200 of the present invention may be incorporated in a non-rechargeable stick cleaner equipped with a power cord.

The cleaner main body 110 is a unit that can be used independently as a handy cleaner, and has a main body grip part 111 on the upper part to be gripped by the user when using it as a handy cleaner, and a lower part that can be used as a handy cleaner. A suction opening 112 is provided for sucking dust when cleaning. Inside the cleaner body 110 are a dust collection chamber 113 for collecting dust, an electric blower 200 for generating a suction airflow necessary for dust collection, a drive circuit 114 for driving the electric blower 200, and a drive circuit. It has a battery unit 115 that supplies power to 114 .

On the other hand, the holding part 120 is a unit to which the cleaner main body 110 can be attached and detached. A suction body 122 for sucking dust and a connecting portion 122a for connecting the suction body 122 and the suction opening 112 are provided.

In addition, the body grip portion 111 of the cleaner body 110 is provided with a body switch portion 111a for turning on/off the drive of the electric blower 200 when used as a handy cleaner. 121 is provided with a switch portion 121a for turning on/off the driving of the electric blower 200 when used as a stick cleaner.

<Electric blower 200>
Next, details of the electric blower 200 of this embodiment will be described with reference to FIGS. 1A to 6, 9, and 10. FIG. The electric blower 200 of this embodiment mainly includes an impeller 1, a rotating shaft 2, a fan casing 3, an upstream housing 4, a downstream housing 5, an upstream motor housing 6, a downstream motor housing 7, and an upstream diffuser blade. 8, a downstream diffuser blade 9, etc., which constitute a blower section 201 and a motor section 202. As shown in FIG.

1A is an external view of the electric blower 200, and FIG. 1B is a longitudinal sectional view of the electric blower 200. FIG. Since the electric blower 200 of the present embodiment is a blower that sucks in air from the upper air intake port 200a and discharges air from the lower air exhaust port 200b when the impeller 1 is rotated, Define downstream. Focusing on the installation direction of the rotating shaft 2, the axial direction and the radial direction are defined as shown in the figure. In this state, the air intake port 200a of the electric blower 200 is directed downward and the exhaust port 200b is directed upward so that dust can be sucked up from the suction port body 122 in the lower part of the electric vacuum cleaner 100 into the upper dust collection chamber 113. It is assumed that the electric blower 200 is installed inside the electric vacuum cleaner 100 (see FIG. 8).

As shown in FIG. 1A, the outer circumference of the electric blower 200 is covered with an outer shell that integrates the fan casing 3, the upstream housing 4, and the downstream housing 5. As shown in FIG. A specific method for integrating these will be described later.

In addition, as shown in FIG. 1B, a rotating shaft 2 is rotatably arranged inside the electric blower 200, and an impeller 1 that rotates integrally with the rotating shaft 2 is fixed to its upper end. In addition, in FIG. 1B, the impeller 1 is fixed by a nut screwed to the upper end of the rotating shaft 2, but the impeller 1 may be fixed by being press-fitted to the tip of the rotating shaft 2. FIG.

When the impeller 1 rotates, inside the electric blower 200, as illustrated on the left side of FIG. hereinafter referred to as the "first flow path F1") and an air flow path indicated by a dotted arrow that branches downstream of the first flow path F1 and circulates from the downstream side to the upstream side in the motor unit 202 (hereinafter referred to as the "second flow A path F2") is formed. Hereinafter, the electric blower 200 of the present embodiment can sufficiently cool the inside of the motor unit 202 while maintaining the suction force in a wide air volume range by circulating a desired air flow through the first flow path F1 and the second flow path F2. The structure of is divided into the blower section 201 and the motor section 202 and will be described in order.

<Blower unit 201>
The blower unit 201 is a unit for the electric vacuum cleaner 100 to generate an air flow for sucking dust, and as shown in FIG. An upstream diffuser blade 8 provided on the inner circumference, a downstream diffuser blade 9 provided on the inner circumference of the downstream housing 5, and the like are arranged. In this embodiment, the upper and lower diffuser blades are provided to control the flow velocity of the air flow on the downstream side of the impeller 1 and to control the static pressure. As long as it can be maintained, it is also possible to omit part or all of the diffuser blades. Each part will be described in order below.

<Impeller 1 and Fan Casing 3>
First, the impeller 1 will be described with reference to FIGS. 2A and 2B. 2A is a perspective view of the impeller 1, and FIG. 2B is a longitudinal sectional view of the impeller 1. FIG. The impeller 1 shown in both figures is an open-type mixed-flow impeller without a shroud plate. has a boss 13 of The impeller 1 of this embodiment may be a diagonal flow impeller having a shroud plate, a centrifugal impeller, or an axial flow impeller.

A metal sleeve 14 is integrally formed on the back side of the hub 11 coaxially with the boss 13 of the impeller 1 . By using such a sleeve 14, it is possible to reduce the variation in the fitting gap between the impeller 1 and the rotating shaft 2, which is likely to occur when the sleeve is not used, and to reduce the imbalance of the impeller 1. Vibration and noise when the impeller 1 is rotationally driven can be reduced. A convex portion 14 a is provided on the downstream side of the sleeve 14 . The function of this convex portion 14a will be described later.

The fan casing 3 is a cover that covers the outer circumference of the impeller 1 and is integrally molded of engineering plastic or thermoplastic resin. As shown in FIG. 1 shroud plate function.

<Upstream Housing 4 and Upstream Diffuser Blade 8>
Next, the upstream housing 4 and the upstream diffuser blades 8 will be described with reference to FIGS. 3A to 3C. 3A is a plan view of the upstream housing 4 viewed from the upstream side, FIG. 3B is a vertical cross-sectional view of the upstream housing 4, and FIG. 3C is a partial cross-sectional view of the upstream housing 4 viewed from the outer circumference. In FIG. 3C, the shroud of the upstream housing 4 is partially omitted to show the shape of the upstream diffuser blade 8 (in particular, the positions of the leading edge 8a and the trailing edge 8b).

The upstream housing 4 and the upstream diffuser blades 8 are integrally molded from engineering plastic or thermoplastic resin. As shown in FIGS. Between the shrouds, a plurality of upstream diffuser blades 8 integrally formed therewith are arranged at regular intervals in the circumferential direction.

The length (chord length) from the leading edge 8a to the trailing edge 8b of the upstream diffuser blade 8 is longer on the outer wall 4b side than on the inner wall 4a side. This is because, downstream of the impeller 1, the wind speed on the outer peripheral side is faster than that on the inner peripheral side. It is for the purpose of planning. Although a configuration in which 15 upstream diffuser blades 8 are provided is exemplified here, the number of upstream diffuser blades 8 can be changed according to the specifications of the electric blower 200 .

Further, as shown in FIGS. 3A and 3C, projections 4c are provided at three equal intervals on the outer periphery of the outer wall 4b of the upstream housing 4, into which the claw portions 5c of the downstream housing 5, which will be described later, are fitted. As a result, the upstream housing 4 and the downstream housing 5 can be integrated while being centered (see FIG. 1B).

In addition, as shown in FIGS. 3A and 3B, fastening portions 4d are provided at two locations on the top surface of the upstream housing 4, and the motor portion 202 can be fastened there while being centered (FIG. 1B). reference).

Further, as shown in FIGS. 3A to 3C, a fitting portion 4e is provided on the outer periphery of the outer wall 4b of the upstream side housing 4 except for the protrusion 4c, and the lower end of the fan casing 3 is fitted into the fitting portion 4e and fixed by adhesion. By doing so, the fan casing 3 and the upstream housing 4 can be integrated while being centered (see FIG. 1B).

<Downstream Housing 5 and Downstream Diffuser Blade 9>
Next, the downstream housing 5 and the downstream diffuser blades 9 will be described with reference to FIGS. 4A to 4C. 4A is a plan view of the downstream housing 5 viewed from the upstream side, FIG. 4B is a vertical sectional view of the downstream housing 5, and FIG. 4C is a partial cross-sectional perspective view of the downstream housing 5 viewed from the outer periphery. In FIG. 4C, the shroud of the downstream housing 5 is partially omitted to show the shape of the downstream diffuser blade 9 (in particular, the positions of the leading edge 9a and the trailing edge 9b).

The downstream housing 5 and the downstream diffuser blades 9 are integrally molded from engineering plastic or thermoplastic resin. As shown in FIGS. Between the shrouds, a plurality of downstream diffuser blades 9 integrally formed therewith are arranged at regular intervals in the circumferential direction. Here, a configuration in which 15 downstream diffuser blades 9 are provided is exemplified. This is because the number of blades 8 and the number of downstream diffuser blades 9 are matched.

In addition, as shown in FIGS. 4A to 4C, claw portions 5c are provided at three locations on the outer circumference of the upper end of the downstream housing 5 at equal intervals, and a portion of the outer circumference of the upper end excluding the claw portions 5c has a fitting portion. 5d is provided. By pressing the lower end of the upstream housing 4 against the fitting portion 5d of the downstream housing 5 and fitting the three claw portions 5c into the three projections 4c, the upstream housing 4 and the downstream housing 5 are separated. It can be integrated while being centered (see FIG. 1B).

Furthermore, as shown in FIGS. 4B and 4C, an annular diffuser 5 e without downstream diffuser blades 9 is provided on the downstream side of the downstream housing 5 . Details of the ring diffuser 5e will be described later.

Here, as shown in FIG. 1B, in this embodiment, either the inner wall 4a of the upstream housing 4 or the inner wall 5a of the downstream housing 5, or the outer wall 4b of the upstream housing 4 or the outer wall 5b of the downstream housing 5 is are also integrated while their radial positions are substantially matched. As a result, the inner surface of each flow path is made smooth and the loss in each flow path is reduced. Further, in this embodiment, the trailing edge 8b of the upstream diffuser blade 8 and the leading edge 9a of the downstream diffuser blade 9 are arranged such that the pair of upstream diffuser blade 8 and downstream diffuser blade 9 function as one diffuser blade. , and the curved surfaces of the upstream diffuser blade 8 and the downstream diffuser blade 9 are smoothly continued. Furthermore, in this embodiment, the thickness of each diffuser blade increases from the upstream side to the downstream side, thereby increasing the static pressure and realizing high efficiency of the blower section 201.

<Motor unit 202>
Next, the motor section 202 will be described with reference to FIGS. 5A and 5B. 5A is a side external view of the motor section 202, and FIG. 5B is a longitudinal sectional view of the motor section 202. FIG. The illustrated motor unit 202 is a unit for rotating the impeller 1 of the blower unit 201, for example, within a range of 50,000 to 200,000 [rpm], and includes a rotating shaft 2, an upstream bearing 21, a downstream bearing 22, and a rotor core. 23, a stator core 24, a collar 25, an upstream motor housing 6, a downstream motor housing 7, and the like. Each part will be described in order below.

<Housing of Motor Unit 202>
As shown in both figures, the motor section 202 has an upstream motor housing 6 and a downstream motor housing 7 as housings for holding the stator core 24 and the like. By fixing the upper surface of 6 with a screw or the like, the motor section 202 can be incorporated in the electric blower 200 (see FIG. 1B).

The upstream motor housing 6 is a housing made of metal (aluminum alloy material, steel material, etc.) that covers the upstream side of the motor section 202, and as shown in FIG. It has an opening 6a. As shown in FIG. 5B, the center of the upper surface of the upstream motor housing 6 protrudes upward, and an upstream bearing 21 that rotatably supports the upstream side of the rotating shaft 2 is provided inside the protrusion. there is Axial positioning of the upstream bearing 21 is performed by an upstream spacer 21 a below the upstream bearing 21 . An axial opening may be provided in the upstream side motor housing 6, and when provided, cooling air can flow to the bearing 21 for cooling.

On the other hand, the downstream motor housing 7 is a housing made of metal (aluminum alloy material, steel material, etc.) that covers the downstream side of the motor section 202, and as shown in FIG. It has a radial opening 7a and a plurality of axial openings 7b on its lower surface. As shown in FIG. 5B, the center of the lower surface of the downstream motor housing 7 protrudes downward, and a downstream bearing 22 that rotatably supports the downstream side of the rotating shaft 2 is provided inside the protrusion. there is A downstream spacer 22a above the downstream bearing 22 positions the downstream bearing 22 in the axial direction.

Further, as shown in FIG. 5A, in this embodiment, the radial opening 6a on the upstream side and the radial opening 7a on the downstream side are installed so as not to overlap in the axial direction. Also, the

radial openings

6a and 7a of each motor housing are arranged so as to axially overlap the axial ends of the coils 24b, which will be described later. The radial openings of each motor housing are arranged uniformly in the circumferential direction. there is As a result, the same flow field is formed at three locations in the circumferential direction inside the motor section 202, so that the temperature distribution in the circumferential direction can be reduced. Note that the number of radial openings and the number of diffuser blades may be set using a predetermined value other than 3 as the greatest common divisor.

In this embodiment, in order to improve the cooling performance of the motor section 202, each motor housing is made of metal to improve heat radiation performance, and a region (exposed portion 24a) where the stator core 24 is exposed is provided between the upper and lower motor housings. However, when the amount of heat generated by the motor section 202 is relatively small, each motor housing may be made of heat-resistant resin, or the upper and lower motor housings may be connected to cool the stator core 24. You may make it the structure which is not exposed.

Although the radial opening 7a and the axial opening 7b of the downstream motor housing 7 can cool the motor only with the radial opening 7a, the presence of the axial opening 7b causes pressure loss when the motor is cooled. can be reduced, the motor cooling air volume increases, and the motor can be cooled.

<Rotor of Motor Unit 202>
As shown in FIG. 5B, a rotor core 23 is fixed to the rotating shaft 2 in a region sandwiched between upper and lower spacers. The rotor core 23 is the rotor of the motor section 202 and contains a rare earth bond magnet such as a samarium iron nitrogen magnet or a neodymium magnet.

Further, as shown in FIG. 5A, a collar 25 is fixed to the rotary shaft 2 protruding from the upper portion of the upstream motor housing 6, and the upper portion of the collar 25 is provided with a concave portion 25a. By fitting the concave portion 25a to the convex portion 14a of the sleeve 14 of the impeller 1, the torque of the rotating shaft 2 can be reliably transmitted to the impeller 1, and the impeller 1 is prevented from spinning. can do.

<Stator of Motor Unit 202>
As shown in FIG. 5B , a stator core 24 that is a stator of motor section 202 is arranged on the outer periphery of motor section 202 so as to surround rotor core 23 that is a rotor of motor section 202 . A coil 24b made of aluminum wire or copper wire covered with a covering material is wound around the winding frame of the stator core 24. When a desired AC power is supplied to the coil 24b from the drive circuit 114 shown in FIG. The stator core 24 can be an electromagnet, and the rotor core 23, rotating shaft 2, and impeller 1 can be rotated together at high speed.

The upstream motor housing 6 is driven into the upstream side of the stator core 24 and fixed with an adhesive, and the downstream side motor housing 7 is driven into the downstream side and fixed with an adhesive. The motor housing 7 can be integrated so that at the level of the upstream end of the coil 24b there is a radial opening 6a in the upstream motor housing 6 and at the level of the downstream end of the coil 24b. , a radial opening 7a in the downstream motor housing 7 may be provided.

<Structures of first flow path F1 and second flow path F2>
Next, the structures of the first flow path F1 and the second flow path F2 of this embodiment will be described in detail with reference to FIGS. 1B and 6A.

As shown in FIG. 1B, the dimensions that define the shapes of the first flow path F1 and the second flow path F2 are the radial height H1 of the downstream diffuser blade 9, the inner surface of the annular diffuser 5e and the downstream motor housing 7. Assuming that the radial distance H2 of the outer surface, the axial length L1 of the inner wall 5a, the axial length L2 of the downstream diffuser blade 9, and the axial length L3 of the annular diffuser 5e, the electric blower 200 of this embodiment In order to improve both the efficiency of the blower unit 201 and the improvement of the cooling efficiency of the motor unit 202, each dimension is set according to the following equations. The action of each formula will be described below with reference to FIG. 6A, which is an enlarged cross-sectional view of the right channel of FIG. 1B.

H1≧0.5×H2 (Equation 1)
More preferably, H1≧0.66×H2 (formula 1′)
0.5×L2≦L1≦L2 (Equation 2)
More preferably, L1≈0.5×L2 (Formula 2′)
L3≧2.5×H1 (Equation 3)
More preferably, L3≧3×H1 (Formula 3′)
When electric power is supplied to the motor section 202 to rotate the impeller 1, as shown in FIG. A flowing second flow path F2 is formed. Then, the second flow path F2 branched from the first flow path F1 is exhausted from the exhaust port 200b of the electric blower 200 through the following flow paths (1) to (5).

(1) First, the air flow branched from the first flow path F1 inside the annular diffuser 5e flows into the motor section 202 through the radial opening 7a and the axial opening 7b on the downstream side. In this embodiment, by arranging the annular diffuser 5e on the outer peripheral side of the radial direction opening 7a on the downstream side, the diffusion of the air flow discharged from the downstream diffuser blade 9 in the outer peripheral direction is suppressed. The airflow branched from the path F1 can be efficiently guided inside the motor section 202 .

(2) The airflow that has flowed into the motor section 202 from the radial opening 7a on the downstream side flows from the downstream side to the upstream side, causing the downstream side bearing 22, the rotor core 23, the stator core 24, and the upstream side bearing in a high temperature state. 21 etc. are efficiently cooled.

(3) The airflow that has flowed upstream inside the motor portion 202 flows out of the motor portion 202 through the radial opening 6a on the upstream side, and then flows into the inner surface of the inner wall 4a of the upstream housing 4 and the upstream motor housing. 6 flows downstream to further cool the exposed portion 24 a of the stator core 24 .

(4) The airflow that has cooled the exposed portion 24a merges with the first flow path F1 near the lower end of the inner wall 5a of the downstream housing 5 . In this embodiment, the radial height H1 of the downstream diffuser blade 9 is set large as in (Formula 1) or (Formula 1'), so that the downstream diffuser blade 9 is attached to the downstream motor housing 7. It can be brought closer, and the flow velocity in the outer peripheral region of the downstream side motor housing 7 can be increased. Further, as shown in (Equation 2'), the lower end of the inner wall 5a of the downstream housing 5 is positioned at a position approximately half the axial length of the downstream diffuser blade 9 (for example, L1/L2=0.5 to 0.5. 6) allows the second flow path F2 to merge with the first flow path F1 in the presence region of the high-speed flow flowing through the downstream diffuser blade 9 . Therefore, due to the venturi effect of the high-speed first flow path F1, the air inside the motor section 202 can be efficiently sucked from the radial opening 6a on the upstream side. The cooling air can be efficiently taken in from the radial opening 7a and the axial opening 7b on the downstream side. That is, the venturi effect of the first flow path F1 can improve the cooling efficiency of the motor section 202 regardless of the operating range of the electric blower 200 .

(5) The airflow that joins the first flow path F1 is exhausted from the exhaust port 200b. In this embodiment, as shown in (Equation 3) or (Equation 3'), an annular diffuser 5e having an axial length L3 corresponding to the radial height H1 of the downstream diffuser blade 9 is provided. Since the axial length L3 of the ring diffuser 5e is sufficiently longer than the radial height H1 of the downstream diffuser blade 9, rapid expansion of the flow path on the downstream side of the downstream diffuser blade 9 is suppressed. As a result, the blowing efficiency of the blower unit 201 is improved.

<Effect of annular diffuser 5e>
Next, the effect of the annular diffuser 5e of this embodiment will be described with reference to the experimental results of FIGS. 9 and 10. FIG. The comparative example shown in FIGS. 9 and 10 corresponds to an electric blower obtained by removing the annular diffuser 5e from the electric blower 200 of FIG. 6A.

In the electric blower of the comparative example, since the ring-shaped diffuser 5e does not exist at the position facing the radial opening 7a on the downstream side, the flow path is formed on the downstream side of the trailing edge 9b of the downstream diffuser blade 9 through which the high-speed air flows. will expand rapidly. In that case, as shown in the experimental results of FIG. 9, the efficiency of the electric blower is greatly deteriorated compared to the electric blower 200 of this embodiment having the annular diffuser 5e. Accordingly, in the electric blower of the comparative example, since the amount of air flowing into the motor portion 202 is reduced, as shown in FIG. (Upstream side bearing 21, downstream side bearing 22), stator core 24, coil 24b, etc. are increased by about 25 to 40K.

Therefore, as is clear from FIGS. 9 and 10, according to the electric blower 200 of the present embodiment provided with the annular diffuser 5e, the blowing capacity of the blower section 201 is greater than that of the electric blower of the comparative example which does not have the annular diffuser. It can be seen that not only the efficiency is improved, but also the cooling efficiency of the motor section 202 is improved.

<Modification>
Next, a modification of the structure of FIG. 6A will be described with reference to FIGS. 6B to 6D.

In FIG. 6B, the radial opening 7a on the downstream side is arranged on the downstream side from FIG. 6A. In this case, the second flow path F2 branches from the first flow path F1 in the vicinity of the position where the innermost air flow of the first flow path F1 shown by the solid line adheres to the downstream motor housing 7. As a result, the amount of air sucked into the motor section 202 from the radial opening 7a on the downstream side increases, and the cooling efficiency of the motor section 202 can be further improved as compared with FIG. 6A.

In FIG. 6C, the radial opening 7a on the downstream side is arranged on the upstream side from FIG. 6A. In this case, of the air flow in the first flow path F1 indicated by the solid line, the innermost air flow adheres to the outer peripheral surface of the downstream motor housing 7 on the upstream side, so that the flow path expands in the annular diffuser 5e. It is possible to suppress the separation of the air flow in the area of , and the blowing efficiency of the blower section 201 can be further increased as compared with that in FIG. 6A.

In FIG. 6D, instead of the radial opening 7a and the axial opening 7b, a corner opening 7c having both functions is provided. In this case, the same effect as in FIG. 6B can be obtained with a simplified configuration.

In addition, in FIGS. 6A to 6D, the annular diffuser 5e is provided on the downstream side of the downstream housing 5, but the annular diffuser 5e may be omitted. In that case, in order to suppress the rapid expansion of the flow path of the first flow path F1 in the vicinity of the radial opening 7a on the downstream side, the downstream diffuser blade is extended to at least the axial position facing the radial opening 7a on the downstream side. 9 should be longer.

It should be noted that the cooling by the venturi effect of this configuration can cool the motor without the diffuser blades of the upstream housing and the downstream housing.

<Effect of this embodiment>
According to the present embodiment described above, an electric blower that is compact and lightweight, has high efficiency in a wide air volume range, and has a high motor cooling efficiency, and a vacuum cleaner equipped with the electric blower are provided. be able to.

It should be noted that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above embodiments have been described in detail to facilitate understanding of the present invention, and are not necessarily limited to those having all the described configurations. In addition, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Moreover, it is possible to add, delete, or replace a part of the configuration of each embodiment with another configuration.

DESCRIPTION OF SYMBOLS 100... Vacuum cleaner, 110... Vacuum cleaner main body, 111... Main body grip part, 111a... Main body switch part, 112... Air intake opening, 113... Dust collection chamber, 114... Drive circuit, 115... Battery unit, 120... Holding part, DESCRIPTION OF SYMBOLS 121... Grip part 121a... Switch part 122... Inlet body 122a... Connection part 130... Charging stand 200... Electric blower 200a... Intake port 200b... Exhaust port 201... Air blower part 202... Motor part, DESCRIPTION OF SYMBOLS 1... Impeller 11... Hub 11a... Hub convex part 12... Blade 13... Boss 13a... Boss curved surface 14... Sleeve 14a... Convex part 2... Rotating shaft 21... Upstream side bearing 21a... Upstream spacer 22 Downstream bearing 22a Downstream spacer 23 Rotor core 24 Stator core 24a Exposed portion 24b Coil 25 Collar 25a Recess 3 Fan casing 4 Upstream Housing 4a... Inner wall 4b... Outer wall 4c... Protrusion 4d... Fastening part 4e... Fitting part 5... Downstream side housing 5a... Inner wall 5b... Outer wall 5c... Claw part 5d... Fitting part 5e Annular diffuser 6 Upstream motor housing 6a Radial opening 7 Downstream motor housing 7a Radial opening 7b Axial opening 7c Corner opening 8 Upstream diffuser blade , 8a... Leading edge 8b... Trailing edge 9... Downstream diffuser blade 9a... Leading edge 9b... Trailing edge F1... First flow path F2... Second flow path

Claims

An electric blower in which a first flow path circulates inside the blower part and a second flow path circulates inside the motor part,
The motor unit includes a rotating shaft, a bearing that rotatably supports the rotating shaft, a rotor core fixed to the rotating shaft, a stator core that surrounds the outer circumference of the rotor core, and the stator core, a motor housing having an upstream radial opening and a downstream radial opening formed in a side surface thereof;
The blower section includes an impeller fixed to the tip of the rotating shaft, a fan casing covering the outer circumference of the impeller, an upstream housing surrounding the upstream outer circumference of the motor section, and a downstream outer circumference of the motor section. a downstream housing enclosing
the first flow path circulates between the inner wall and the outer wall of the upstream housing and between the inner wall and the outer wall of the downstream housing;
The second flow path extends from the downstream radial opening to the rotational axis direction opening of the downstream motor housing, the inside of the motor section, the upstream radial opening, and between the motor housing and the inner wall of the upstream housing. , and between inner walls of the motor housing and the downstream housing,
An electric blower, wherein an annular diffuser facing the downstream radial opening is provided on the downstream side of the downstream housing.
In the electric blower according to claim 1,
An upstream diffuser blade is provided between an inner wall and an outer wall of the upstream housing,
An electric blower comprising a downstream diffuser blade provided between an inner wall and an outer wall of the downstream housing.
In the electric blower according to claim 2,
An electric blower that satisfies any one of the following expressions, where H1 is the radial height of the downstream diffuser blade, and H2 is the radial distance between the inner surface of the annular diffuser and the outer surface of the motor housing. .
H1≧0.5×H2,
H1≧0.66×H2
In the electric blower according to claim 2,
An electric blower that satisfies any one of the following expressions, where L1 is the axial length of the inner wall of the downstream housing and L2 is the axial length of the downstream diffuser blade.
0.5×L2≦L1≦L2,
L1≈0.5×L2
In the electric blower according to claim 2,
An electric blower that satisfies any one of the following expressions, where H1 is the radial height of the downstream diffuser blade and L3 is the axial length of the annular diffuser.
L3≧2.5×H1,
L3 ≧ 3×H1
In the electric blower according to claim 1,
The motor housing includes an upstream motor housing that covers the upstream side of the stator core and a downstream motor housing that covers the downstream side of the stator core, and the second flow path is formed between the upstream motor housing and the downstream motor housing. An electric blower characterized by circulating along the exposed portion of the stator core that is not covered with.
An electric blower in which a first flow path circulates inside the blower part and a second flow path circulates inside the motor part,
The motor unit includes a rotating shaft, a bearing that rotatably supports the rotating shaft, a rotor core fixed to the rotating shaft, a stator core that surrounds the outer circumference of the rotor core, and the stator core, a motor housing having an upstream radial opening and a downstream radial opening formed in a side surface thereof;
The blower section includes an impeller fixed to the tip of the rotating shaft, a fan casing covering the outer circumference of the impeller, an upstream housing surrounding the upstream outer circumference of the motor section, and a downstream outer circumference of the motor section. a downstream housing enclosing
the first flow path flows between the inner wall and the outer wall of the upstream housing and between the inner wall and the outer wall of the upstream housing;
The second flow path extends through the downstream radial opening, the interior of the motor section, the upstream radial opening, between the motor housing and the inner wall of the upstream housing, and between the motor housing and the downstream housing. circulating between the inner walls of
An electric blower, wherein a downstream diffuser blade facing the downstream radial opening is provided downstream of the downstream housing.
In the electric blower according to any one of claims 1 to 7,
An electric blower characterized by having an axial opening in an upstream or downstream motor housing or both.
A vacuum cleaner comprising the electric blower according to any one of claims 1 to 8.