Electric air blower and vacuum cleaner comprising the same

Abstract

To provide an electric air blower that is compact and lightweight, has high efficiency in a wide air volume range, and in which cooling efficiency of a motor is high.SOLUTION: In an electric air blower, a first flow passage passes through an air blower part, and a second flow passage passes through a motor part. The motor part comprises a motor housing holding a stator core, in which an upstream side radial opening and a downstream side radial opening are opened in a side surface. The air blower part comprises a fan casing, an upstream side housing surrounding an upstream side outer periphery of the motor part, and a downstream side housing surrounding a downstream side outer periphery of the motor part. The first flow passage passes through 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. The second flow passage passes through the downstream side radial opening, the inside of the motor part, the upstream side radial opening, between the motor housing and the inner wall and the upstream side housing, and between the motor housing and the inner wall of the downstream side housing. An annular diffuser opposed to the downstream side radial opening is provided on the downstream side of the downstream side housing.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present invention relates to an electric blower and a vacuum cleaner equipped with the same.

Background Art

[0002] As an example of an electric blower (air blowing device) incorporated in a vacuum cleaner, Patent Document 1 describes "an impeller 10 that rotates around a central axis C extending vertically, a motor 20 that is disposed below the impeller and has a stator 24 to rotate 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 a first flow path 5 in a gap with the motor housing. The upper part of the fan casing covers above the impeller and has an intake port 3 that opens vertically. An exhaust port 4 that communicates with the intake port via the first flow path is provided at the lower part of the fan casing. The motor housing is provided with an inlet 21a that penetrates in the radial direction and communicates with the first flow path below the upper surface of the stator fixed to the inner surface of the motor housing. The motor housing has a second flow path 6 that extends upward from the inlet and communicates with a space above the stator."

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is known that the operating air volume of a vacuum cleaner varies greatly depending on factors such as clogging of the filter by dust and operating conditions such as the material of the floor to be cleaned. Therefore, as an electric blower for a vacuum cleaner, an electric blower with a strong suction force in a wide air volume range is required.

[0005] In addition, from the perspective of the usability of the vacuum cleaner, miniaturization and weight reduction of the electric blower are also required. However, along with this, the heat dissipation area of the electric blower decreases, and the heat generation density inside the electric blower increases. Therefore, it is necessary to improve the cooling performance of the motor and bearings.

[0006] In particular, vacuum cleaners driven by a battery (secondary battery), such as cordless stick-type cleaners and autonomous driving-type cleaners (robot cleaners), have low power consumption of the electric blower and a small maximum air volume due to the battery capacity. Therefore, there is a problem that the dust conveying ability decreases when the filter is clogged, and the suction power of the vacuum cleaner decreases. Furthermore, battery-driven vacuum cleaners are required to be small and lightweight, and the electric blower mounted on the vacuum cleaner is required to have strong suction power in a wide air volume range and be small.

[0007] Here, if a diffuser vane (referred to as "static vane 40" in Patent Document 1) is used, excellent pressure recovery can be achieved at the designed air volume. However, when the air volume decreases due to factors such as filter clogging compared to the designed air volume, the diffuser performance may decrease due to the mismatch between the inlet angle of the diffuser vane and the inflow angle of the air flow into the diffuser, and the suction power of the vacuum cleaner may decrease.

[0008] In addition, in the blower device of Patent Document 1, as shown in FIG. 4 and the like of the same document, a part of the air flow S flowing through the outer first flow path 5 flows into the inner second flow path 6 through the inlet 21a provided on the peripheral wall of the motor housing 21, cools the upper bearing 26, and then further cools the lower bearing 26, and is exhausted to the outside of the blower device 1 from the outlet (outlet 29a) of the second flow path 6 without merging with the first flow path 5. In this way, when adopting a configuration in which the second flow path 6 branched from the first flow path 5 does not merge with the first flow path 5, due to the pressure loss (resistance) when a part of the air flow S flowing through the first flow path 5 branches into the second flow path 6, in the first flow path 5, the air volume on the downstream side of the inlet 21a (branch point) is reduced compared to the air volume on the upstream side of the inlet 21a (branch point).

[0009] In addition, since the second flow path 6 of Patent Document 1 is small in size, the flow path area is small. Further, since it flows while bending inside the motor 20, the pressure loss of the flow path is large, the cooling air volume decreases, the temperature inside the motor 20 increases, and there is a concern that the motor efficiency decreases.

[0010] The present invention solves the above problems, and an object thereof is to provide an electric blower that is small and lightweight, has high efficiency in a wide air volume range, and has high cooling efficiency for the motor, and a vacuum cleaner equipped with the same.

Means for Solving the Problems

[0011] In order to solve the above problems, the electric blower of the present invention is an electric blower in which a first flow path flows inside the blower unit and a second flow path flows inside the motor unit. 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 disposed so as to surround the outer periphery of the rotor core, and a motor housing that holds the stator core and has an upstream radially opening and a downstream radially opening on the side surface. The blower unit includes an impeller fixed to the tip of the rotating shaft, a fan casing that covers the outer periphery of the impeller, an upstream housing that surrounds the upstream outer periphery of the motor unit, and a downstream housing that surrounds the downstream outer periphery of the motor unit. 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 downstream housing. The second flow path flows through the downstream radially opening, the inside of the motor unit, the upstream radially opening, between the motor housing and the inner wall of the upstream housing, and between the motor housing and the inner wall of the downstream housing. An electric blower is provided with an annular diffuser facing the downstream radially opening on the downstream side of the downstream housing.

Effects of the Invention

[0012] According to the present invention, it is possible to provide an electric blower that is small and lightweight, has high efficiency in a wide air volume range, and has high cooling efficiency for the motor, and a vacuum cleaner equipped with the same.

Brief Description of the Drawings

[0013]

Fig. 1A

Fig. 1B

Fig. 2A

Fig. 2B

Fig. 3A

Fig. 3B

Fig. 3C

Fig. 4A

Fig. 4B

Fig. 4C

Fig. 5A

Fig. 5B

Fig. 6A

Fig. 6B

Fig. 6C

Fig. 6D

Fig. 7

Fig. 8

Fig. 9

Fig. 10

Modes for Carrying Out the Invention

[0014] Hereinafter, an embodiment of the electric blower of the present invention and a vacuum cleaner equipped with the same will be described in detail with reference to the drawings.

[0015] <Schematic Configuration of Vacuum Cleaner 100> First, the 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 the vacuum cleaner 100, and FIG. 8 is a longitudinal sectional view of the vacuum cleaner 100. The illustrated vacuum cleaner 100 is a rechargeable cordless stick vacuum cleaner in which the cleaner main body 110 is attached to the holding part 120 and can be charged when placed on the charging base 130. Here, a rechargeable cordless stick vacuum cleaner is exemplified, but the electric blower 200 of the present invention may be incorporated in a non-rechargeable stick vacuum cleaner equipped with a power cord.

[0016] The cleaner main body 110 is a unit that can be used alone as a handy vacuum cleaner. It is provided with a main body grip part 111 that a user grips when using it as a handy vacuum cleaner at the upper part, and an air intake opening 112 that sucks dust when using it as a handy vacuum cleaner at the lower part. In addition, inside the cleaner main body 110, there are provided a dust collection chamber 113 for collecting dust, an electric blower 200 for generating a suction air flow necessary for dust collection, a drive circuit 114 for driving the electric blower 200, and a battery unit 115 for supplying power to the drive circuit 114.

[0017] On the other hand, the holding part 120 is a unit to which the cleaner main body 110 can be attached and detached. It is provided with a grip part 121 that a user grips when using it as a stick vacuum cleaner at the upper part, a suction port body 122 that sucks dust when using it as a stick vacuum cleaner at the lower part, and a connection part 122a that connects the suction port body 122 and the air intake opening 112.

[0018] In addition, a main body switch portion 111a for turning on / off the drive of the electric blower 200 is provided on the main body grip portion 111 of the cleaner main body 110, and a switch portion 121a for turning on / off the drive of the electric blower 200 is provided on the grip portion 121 of the holding portion 120 when used as a stick vacuum cleaner.

[0019] <Electric blower 200> Next, the details of the electric blower 200 of the present embodiment will be described with reference to FIGS. 1A to 6, 9, and 10. The electric blower 200 of the present 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, an upstream diffuser vane 8, a downstream diffuser vane 9, etc., and a blower unit 201 and a motor unit 202 are constituted by these.

[0020] FIG. 1A is an external view of the electric blower 200, and FIG. 1B is a longitudinal sectional view of the electric blower 200. Since the electric blower 200 of the present embodiment is a blower that sucks air from the upper intake port 200a and discharges air from the lower exhaust port 200b when the impeller 1 is rotated, the upstream side and the downstream side are defined as shown in the figure. Also, paying attention to the installation direction of the rotating shaft 2, the axial direction and the radial direction are defined as shown in the figure. It is assumed that the electric blower 200 is installed inside the electric cleaner 100 with the intake port 200a of the electric blower 200 facing downward and the exhaust port 200b facing upward so that dust can be sucked from the lower suction body 122 of the electric cleaner 100 into the upper dust collection chamber 113 (see FIG. 8).

[0021] As shown in FIG. 1A, the outer periphery of the electric blower 200 is covered with an outer shell in which the three members of the fan casing 3, the upstream housing 4, and the downstream housing 5 are integrated. The specific method of integrating these will be described later.

[0022] Further, as shown in FIG. 1B, inside the electric blower 200, a rotating shaft 2 is rotatably arranged, and at the upper end thereof, an impeller 1 that rotates integrally with the rotating shaft 2 is fixed. In FIG. 1B, the impeller 1 is fixed by a nut screwed onto the upper end of the rotating shaft 2, but the impeller 1 may also be fixed by press-fitting it onto the tip of the rotating shaft 2.

[0023] When this impeller 1 rotates, inside the electric blower 200, as illustrated on the left side of FIG. 1B, an air flow path indicated by a solid line arrow (hereinafter referred to as "first flow path F1") that circulates through the blower unit 201 from the suction port 200a toward the exhaust port 200b, and an air flow path indicated by a dotted line arrow (hereinafter referred to as "second flow path F2") that branches on the downstream side of the first flow path F1 and circulates through the motor unit 202 from the downstream side to the upstream side are formed. Hereinafter, the structure of the electric blower 200 of the present embodiment that can circulate a desired air flow through the first flow path F1 and the second flow path F2 and sufficiently cool the inside of the motor unit 202 while maintaining suction force in a wide air volume range will be sequentially described by dividing it into the blower unit 201 and the motor unit 202.

[0024] <Blower unit 201> The blower unit 201 is a unit for generating an air flow for the vacuum cleaner 100 to suck dust. As shown in FIG. 1B, in order from the upstream side, an impeller 1 which is a rotating blade, an upstream diffuser blade 8 provided on the inner circumference of the upstream housing 4, a downstream diffuser blade 9 provided on the inner circumference of the downstream housing 5, etc. are arranged. In the present embodiment, upper and lower diffuser blades are provided to control the flow velocity of the air flow on the downstream side of the impeller 1 or to control the static pressure, but as long as the Venturi effect described later can be sufficiently maintained, a configuration in which part or all of the diffuser blades are omitted may also be adopted. Hereinafter, each part will be sequentially described.

[0025] <Impeller 1 and fan casing 3> First, the impeller 1 will be described with reference to FIGS. 2A and 2B. FIG. 2A is a perspective view of the impeller 1, and FIG. 2B is a longitudinal sectional view of the impeller 1. The impeller 1 in both figures is an open-type mixed-flow impeller without a shroud plate, and has a hub 11, a plurality of blades 12, and a boss 13 for inserting the rotating shaft 2, which are integrally formed of engineering plastic or thermoplastic resin. Note that the impeller 1 of this embodiment may be a mixed-flow impeller with a shroud plate, or may be a centrifugal impeller or an axial-flow impeller.

[0026] On the back side of the hub 11, a metal sleeve 14 is integrally provided 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 clearance 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, so that the vibration and noise during the rotational drive of the impeller 1 can be reduced. In addition, a convex portion 14a is provided on the downstream side of the sleeve 14. The function of this convex portion 14a will be described later.

[0027] The fan casing 3 is a cover that covers the outer periphery of the impeller 1 and is integrally formed of engineering plastic or thermoplastic resin. As shown in FIG. 1B, an air inlet 200a is opened on the upstream side, and it also functions as a shroud plate of the impeller 1.

[0028] <Upstream housing 4 and upstream diffuser vane 8> Next, the upstream housing 4 and the upstream diffuser vane 8 will be described with reference to FIGS. 3A to 3C. FIG. 3A is a plan view of the upstream housing 4 as viewed from the upstream side, FIG. 3B is a longitudinal sectional view of the upstream housing 4, and FIG. 3C is a partial sectional view of the upstream housing 4 as viewed from the outer periphery. In FIG. 3C, by partially omitting the shroud of the upstream housing 4, the shape of the upstream diffuser vane 8 (particularly, the positions of the leading edge 8a and the trailing edge 8b) is shown.

[0029] The upstream housing 4 and the upstream diffuser vanes 8 are integrally molded from engineering plastics or thermoplastic resins. As shown in FIGS. 3A to 3C, between the inner wall 4a (hub) and the outer wall 4b (shroud) of the upstream housing 4, a plurality of upstream diffuser vanes 8 integrally molded therewith are arranged at equal intervals in the circumferential direction.

[0030] The length (chord length) from the leading edge 8a to the trailing edge 8b of the upstream diffuser vane 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. Therefore, by making the outer side longer than the inner side of the upstream diffuser vane 8, losses can be suppressed while achieving high efficiency of the blower. Here, a configuration in which 15 upstream diffuser vanes 8 are provided is illustrated, but the number of upstream diffuser vanes 8 can be changed according to the specifications of the electric blower 200.

[0031] Also, as shown in FIGS. 3A and 3C, protrusions 4c are provided at three equal intervals on the outer periphery of the outer wall 4b of the upstream housing 4. By fitting the claw portions 5c of the downstream housing 5 described later here, the upstream housing 4 and the downstream housing 5 can be integrated while centering (see FIG. 1B).

[0032] Also, as shown in FIGS. 3A and 3B, fastening portions 4d are provided at two locations on the upper surface of the upstream housing 4. The motor portion 202 can be fastened here while centering (see FIG. 1B).

[0033] Furthermore, as shown in FIGS. 3A to 3C, a fitting portion 4e is provided on the portion of the outer periphery of the outer wall 4b of the upstream housing 4 other than the protrusions 4c. By fitting and adhesively fixing the lower end of the fan casing 3 here, the fan casing 3 and the upstream housing 4 can be integrated while centering (see FIG. 1B).

[0034] <Downstream housing 5 and downstream diffuser vanes 9> Next, the downstream housing 5 and the downstream diffuser vanes 9 will be described with reference to FIGS. 4A to 4C. FIG. 4A is a plan view of the downstream housing 5 as viewed from the upstream side, FIG. 4B is a longitudinal sectional view of the downstream housing 5, and FIG. 4C is a partial sectional perspective view of the downstream housing 5 as 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 vanes 9 (particularly, the positions of the leading edge 9a and the trailing edge 9b).

[0035] The downstream housing 5 and the downstream diffuser vanes 9 are integrally molded from engineering plastics or thermoplastic resins. As shown in FIGS. 4A to 4C, a plurality of downstream diffuser vanes 9 integrally molded therewith are arranged at equal intervals in the circumferential direction between the inner wall 5a (hub) and the outer wall 5b (shroud) of the downstream housing 5. Here, a configuration in which 15 downstream diffuser vanes 9 are provided is illustrated. This is because the downstream diffuser vanes 9 are arranged downstream of each upstream diffuser vane 8, so that the number of upstream diffuser vanes 8 and the number of downstream diffuser vanes 9 are made the same.

[0036] Also, as shown in FIGS. 4A to 4C, claw portions 5c are provided at three equally spaced positions on the outer periphery of the upper end of the downstream housing 5, and a fitting portion 5d is provided at a portion other than the claw portions 5c on the outer periphery of the upper end. 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 protrusions 4c, the upstream housing 4 and the downstream housing 5 can be integrated while centering (see FIG. 1B).

[0037] Furthermore, as shown in FIGS. 4B and 4C, an annular diffuser 5e without the downstream diffuser vanes 9 is provided on the downstream side of the downstream housing 5. Details of this annular diffuser 5e will be described later.

[0038] Here, as shown in FIG. 1B, in this embodiment, for any combination of the inner wall 4a of the upstream housing 4 and the inner wall 5a of the downstream housing 5, and the outer wall 4b of the upstream housing 4 and the outer wall 5b of the downstream housing 5, they are integrated while making the radial positions substantially coincide. Thereby, the inner surfaces of the respective flow paths are smoothed, and the losses in the respective flow paths are reduced. Further, in this embodiment, the circumferential positions of the trailing edge 8b of the upstream diffuser vane 8 and the leading edge 9a of the downstream diffuser vane 9 are made to coincide so that the pair of upstream diffuser vanes 8 and downstream diffuser vanes 9 function as one diffuser vane, and the curved surfaces of the upstream diffuser vane 8 and the downstream diffuser vane 9 are smoothly continuous. Furthermore, in this embodiment, by making the thickness of each diffuser vane increase from the upstream side to the downstream side, the static pressure can be increased, and the high efficiency of the blower unit 201 can be realized.

[0039] <Motor unit 202> Next, the motor unit 202 will be described with reference to FIGS. 5A and 5B. FIG. 5A is a side external view of the motor unit 202, and FIG. 5B is a longitudinal sectional view of the motor unit 202. 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 is composed of a rotating shaft 2, an upstream bearing 21, a downstream bearing 22, a rotor core 23, a stator core 24, a collar 25, an upstream motor housing 6, a downstream motor housing 7, and the like. Hereinafter, each part will be described sequentially.

[0040] <Housing of the motor unit 202> As shown in both figures, the motor unit 202 has an upstream motor housing 6 and a downstream motor housing 7 as a housing for holding the stator core 24 and the like. By fixing the upper surface of the upstream motor housing 6 to the lower surface of the upstream housing 4 with screws or the like, the motor unit 202 can be built into the electric blower 200 (see FIG. 1B).

[0041] The upstream motor housing 6 is a metal housing (such as an aluminum alloy material or a steel material) that covers the upstream side of the motor unit 202. As shown in Fig. 5A, it has a plurality of (for example, six) radially openings 6a on the side surface. Further, 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. And the axial positioning of the upstream bearing 21 is performed by an upstream spacer 21a below the upstream bearing 21. Note that an axial opening may be provided in the upstream motor housing 6. When provided, cooling air can flow to the bearing 21 for cooling.

[0042] On the other hand, the downstream motor housing 7 is a metal housing (such as an aluminum alloy material or a steel material) that covers the downstream side of the motor unit 202. As shown in Fig. 5A, it has a plurality of (for example, six) radially openings 7a on the side surface and a plurality of axial openings 7b on the lower surface. Further, 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. And the axial positioning of the downstream bearing 22 is performed by a downstream spacer 22a above the downstream bearing 22.

[0043] Also, as shown in Fig. 5A, in this embodiment, the upstream radial opening 6a and the downstream radial opening 7a are installed so as not to overlap in the axial direction. Further, the radial openings 6a, 7a of each motor housing are arranged so as to overlap in the axial direction with the axial end portions of the coil 24b described later. Note that the radial openings of each motor housing are uniformly arranged in the circumferential direction, and the number of openings and the number of diffuser vanes are set so that the greatest common divisor of the number of radial openings and the number of diffuser vanes is 3. Thereby, inside the motor unit 202, the same flow field is formed at three locations in the circumferential direction, so that the circumferential temperature distribution can be reduced. Note that the number of radial openings and the number of diffuser vanes may be set with a predetermined value other than 3 as the greatest common divisor.

[0044] In this embodiment, in order to enhance the cooling performance of the motor unit 202, each motor housing is made of metal to improve the heat dissipation performance, and a region (exposed portion 24a) where the stator core 24 is exposed is provided between the upper and lower motor housings so that the stator core 24 can be cooled from the outside. However, when the heat generation amount of the motor unit 202 is relatively small, etc., each motor housing may be made of heat-resistant resin, or the upper and lower motor housings may be connected to form a structure in which the stator core 24 is not exposed.

[0045] Also, for the radial opening 7a and the axial opening 7b of the downstream motor housing 7, although motor cooling is possible with only the radial opening 7a, the presence of the axial opening 7b can reduce the pressure loss when taking in motor cooling, increase the motor cooling air volume, and enable motor cooling.

[0046] <The rotor of the motor unit 202> As shown in FIG. 5B, on the rotating shaft 2, a rotor core 23 is fixed in a region sandwiched between upper and lower spacers. This rotor core 23 is a rotor of the motor unit 202 incorporating a rare earth-based bonded magnet such as a samarium iron nitrogen magnet or a neodymium magnet.

[0047] Also, as shown in FIG. 5A, a collar 25 is fixed to the rotating shaft 2 protruding from the upper part of the upstream motor housing 6, and a recess 25a is provided in the upper part of the collar 25. By fitting this recess 25a to the convex portion 14a of the sleeve 14 of the impeller 1 described above, the torque of the rotating shaft 2 can be reliably transmitted to the impeller 1, and the idling of the impeller 1 can be prevented.

[0048] <The stator of the motor unit 202> As shown in FIG. 5B, on the outer periphery of the motor unit 202, a stator core 24, which is the stator of the motor unit 202, is arranged so as to surround a rotor core 23, which is the rotor of the motor unit 202. A coil 24b, in which an aluminum wire or a copper wire is covered with a coating material, is wound around the winding frame portion of the stator core 24. By supplying desired AC power from the drive circuit 114 in FIG. 8 to this coil 24b, the stator core 24 can be made into an electromagnet, and the rotor core 23, the rotary shaft 2, and the impeller 1 can be integrally rotated at high speed.

[0049] Note that the upstream motor housing 6 is driven into the upstream side of the stator core 24 and fixed with an adhesive, and the downstream motor housing 7 is driven into the downstream side and fixed with an adhesive material, so that the stator core 24, the upstream motor housing 6, and the downstream motor housing 7 can be integrated. Thereby, a radial opening 6a of the upstream motor housing 6 can be provided at the height of the upstream end portion of the coil 24b, and a radial opening 7a of the downstream motor housing 7 can be provided at the height of the downstream end portion of the coil 24b.

[0050] <Structure of the first flow path F1 and the second flow path F2> Next, with reference to FIGS. 1B and 6A, the structures of the first flow path F1 and the second flow path F2 of the present embodiment will be described in detail.

[0051] As shown in FIG. 1B, when the dimensions defining the shapes of the first flow path F1 and the second flow path F2 are the radial height H1 of the downstream diffuser vane 9, the radial distance H2 between the inner surface of the annular diffuser 5e and the outer surface of the downstream motor housing 7, the axial length L1 of the inner wall 5a, the axial length L2 of the downstream diffuser vane 9, and the axial length L3 of the annular diffuser 5e, in the electric blower 200 of the present embodiment, in order to achieve both an improvement in the blower efficiency of the blower unit 201 and an improvement in the cooling efficiency of the motor unit 202, each dimension is set by the following formulas. Hereinafter, the operation of each formula will be described with reference to FIG. 6A, which is an enlarged cross-sectional view of the right flow path in FIG. 1B.

[0052] H1 ≧ 0.5×H2 ··· (Equation 1) More preferably, H1 ≧ 0.66×H2 ··· (Equation 1’) 0.5×L2 ≦ L1 ≦ L2 ··· (Equation 2) More preferably, L1≒0.5×L2 ··· (Equation 2’) L3 ≧ 2.5×H1 ··· (Equation 3) More preferably, L3 ≧ 3×H1 ··· (Equation 3’) When power is supplied to the motor unit 202 to rotate the impeller 1, as shown in Fig. 6A, inside the electric blower 200, a first flow path F1 flowing through the blower unit 201 and a second flow path F2 mainly flowing inside the motor unit 202 are formed. And 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).

[0053] (1) First, the air flow branched from the first flow path F1 inside the annular diffuser 5e flows into the inside of the motor unit 202 from the downstream radial opening 7a and the axial opening 7b. In this embodiment, by disposing the annular diffuser 5e on the outer peripheral side of the downstream radial opening 7a, diffusion of the air flow flowing out from the downstream diffuser blade 9 in the outer peripheral direction is suppressed, and the air flow branched from the first flow path F1 can be efficiently guided into the inside of the motor unit 202.

[0054] (2) The air flow flowing into the inside of the motor unit 202 from the downstream radial opening 7a efficiently cools the downstream bearing 22, the rotor core 23, the stator core 24, the upstream bearing 21, etc. in a high-temperature state while flowing from the downstream side to the upstream side.

[0055] (3) The air flow that has flowed through the inside of the motor unit 202 to the upstream side flows out of the motor unit 202 from the upstream radial opening 6a, and then flows downstream through the gap between the inner surface of the inner wall 4a of the upstream housing 4 and the outer surface of the upstream motor housing 6 to further cool the exposed portion 24a of the stator core 24.

[0056] (4) The air flow 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, since the radial height H1 of the downstream diffuser blade 9 is set large as in (Equation 1) or (Equation 1'), the downstream diffuser blade 9 can be brought closer to the downstream motor housing 7, and the flow velocity in the outer peripheral region of the downstream motor housing 7 can be increased. Further, if the lower end of the inner wall 5a of the downstream housing 5 is arranged at a position approximately half the axial length of the downstream diffuser blade 9 (for example, L1 / L2 = 0.5 to 0.6) as in (Equation 2'), the second flow path F2 can be merged into the first flow path F1 in the region where the high-speed flow passing through the downstream diffuser blade 9 exists. Therefore, due to the Venturi effect of the high-speed first flow path F1, the air inside the motor unit 202 can be efficiently sucked from the upstream radial opening 6a, and as a result, the cooling air can be efficiently taken into the interior of the motor unit 202, which has become a negative pressure, from the downstream radial opening 7a and the axial opening 7b. That is, due to the Venturi effect of the first flow path F1, the cooling efficiency of the motor unit 202 can be improved regardless of the operating range of the electric blower 200.

[0057] (5) The air flow that has merged into the first flow path F1 is exhausted from the exhaust port 200b. In this embodiment, an annular diffuser 5e with an axial length L3 corresponding to the radial height H1 of the downstream diffuser blade 9 is provided as shown in (Equation 3) or (Equation 3'). Since the axial length L3 of the annular diffuser 5e is sufficiently longer than the radial height H1 of the downstream diffuser blade 9, the sudden expansion of the flow path downstream of the downstream diffuser blade 9 is suppressed, and as a result, the blowing efficiency of the blower unit 201 is improved.

[0058] <Effect of the annular diffuser 5e> Next, with reference to the experimental results of FIGS. 9 and 10, the effect of the annular diffuser 5e of this embodiment will be described. The comparative examples shown in FIGS. 9 and 10 correspond to an electric blower in which the portion of the annular diffuser 5e is removed from the electric blower 200 of FIG. 6A.

[0059] In the electric blower of the comparative example, since the annular diffuser 5e does not exist at the position facing the radially outward opening 7a on the downstream side, the flow path rapidly expands downstream of the trailing edge 9b of the downstream diffuser blade 9 through which a high-speed air flow passes. In that case, as shown in the experimental results of FIG. 9, the blower efficiency deteriorates significantly compared to the electric blower 200 of the present embodiment provided with the annular diffuser 5e. Along with this, in the electric blower of the comparative example, since the amount of air flowing into the motor unit 202 decreases, as shown in FIG. 10, the temperature of the bearings (upstream bearing 21, downstream bearing 22), stator core 24, coil 24b, etc. inside the motor unit 202 is about 25 to 40 K higher than that of the electric blower 200 of the present embodiment.

[0060] 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, compared to the electric blower of the comparative example without the annular diffuser, not only is the blowing efficiency of the blower unit 201 improved, but it can also be seen that the cooling efficiency of the motor unit 202 is improved.

[0061] <Modification Example> Next, a modification of the structure of FIG. 6A will be described with reference to FIGS. 6B to 6D.

[0062] FIG. 6B shows the radially outward opening 7a on the downstream side arranged further downstream than in FIG. 6A. In this case, among the air flows in the first flow path F1 indicated by the solid line, the second flow path F2 branches from the first flow path F1 in the vicinity of the position where the air flow on the innermost peripheral side adheres to the downstream motor housing 7. Therefore, the amount of air sucked into the motor unit 202 from the radially outward opening 7a on the downstream side increases, and the cooling efficiency of the motor unit 202 can be further enhanced compared to FIG. 6A.

[0063] FIG. 6C shows the radially outward opening 7a on the downstream side arranged further upstream than in FIG. 6A. In this case, among the air flows in the first flow path F1 indicated by the solid line, since the air flow on the innermost peripheral side adheres to the outer peripheral surface of the downstream motor housing 7 further upstream, the separation of the air flow in the region of the annular diffuser 5e where the flow path expands can be suppressed, and the blowing efficiency of the blower unit 201 can be further enhanced compared to FIG. 6A.

[0064] FIG. 6D shows a configuration in which a corner opening 7c having the functions of both the above-described radial opening 7a and axial opening 7b is provided instead of them. In this case, with a simplified configuration, the same effect as that of FIG. 6B can be obtained.

[0065] In FIGS. 6A to 6D, an annular diffuser 5e is provided on the downstream side of the downstream housing 5. However, a configuration in which the annular diffuser 5e is omitted may also be used. 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 downstream radial opening 7a, the downstream diffuser blade 9 may be lengthened at least to the axial position facing the downstream radial opening 7a.

[0066] Note that, with the cooling by the Venturi effect of this configuration, the motor can be cooled even without the diffuser blades of the upstream housing or the downstream housing.

[0067] <Effects of this embodiment> According to the present embodiment described above, it is possible to provide an electric blower that is small and lightweight, has high efficiency in a wide air volume range, and also has high motor cooling efficiency, and a vacuum cleaner equipped with the same.

[0068] Note that the present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Also, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Also, for a part of the configuration of each embodiment, addition, deletion, or replacement with other configurations is possible.

Description of reference numerals

[0069] 100 Vacuum cleaner 110 Cleaner main body 111 Main body grip part 111a Main body switch part 112 Intake opening 113 Dust collection chamber 114 Drive circuit 115 Battery unit 120 Holding part 121 Grip part 121a Switch part 122 Suction port body 122a Connection part 130 Charging stand 200 Electric blower 200a Intake port 200b Exhaust port 201 Blower part 202 Motor part 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 bearing 21a Upstream spacer 22 Downstream bearing 22a Downstream spacer 23 Rotor core 24 Stator core 24a Exposed part 24b Coil 25 Collar 25a Concave part 3 Fan casing 4 Upstream housing 4a Inner wall 4b Outer wall 4c Protrusion 4d Fastening part 4e Fitting part 5 Downstream 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 vane 8a Leading edge 8b Trailing edge 9 Downstream diffuser vane 9a Leading edge 9b Trailing edge F1 First flow path F2 Second flow path

Claims

1. An electric blower having a first flow path in a blower unit and a second flow path in a motor unit, 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 disposed to surround the outer periphery of the rotor core, and a bearing that holds the stator core. a motor housing having an upstream radial opening and a downstream radial opening on a side surface, the blower unit including an impeller fixed to a tip of the rotary shaft, a fan casing covering an outer periphery of the impeller, an upstream housing surrounding an outer periphery of the upstream side of the motor unit; and a downstream housing surrounding an outer periphery of the downstream side of the motor unit, the first flow passage extends between an inner wall and an outer wall of the upstream housing and between an inner wall and an outer wall of the downstream housing; the second flow passage passes through the downstream radial opening, an interior of the motor portion, the upstream radial opening, a gap between the motor housing and an inner wall of the upstream housing, and a gap between the motor housing and an inner wall of the downstream housing; a downstream housing having a radial opening extending from the downstream housing to the downstream side of the downstream housing;

2. The electric blower according to claim 1, an upstream diffuser vane is provided between an inner wall and an outer wall of the upstream housing; a downstream diffuser vane provided between the inner wall and the outer wall of the downstream housing.

3. The electric blower according to claim 2, 1. An electric blower comprising: a downstream diffuser vane having a radial height H1 and a radial distance between an inner surface of the annular diffuser and an outer surface of the motor housing H2, the ... and the H1 ≧ 0.5×H2, H1 ≧ 0.66×H2

4. The electric blower according to claim 2, 1. An electric blower comprising: a downstream housing having an inner wall with an axial length of L1; and a downstream diffuser vane with an axial length of L2; the downstream housing having an inner wall with an axial length of L1; 0.5×L2 ≦ L1 ≦ L2, L1 ≒ 0.5 × L2

5. The electric blower according to claim 2, 1. An electric blower comprising: a downstream diffuser vane having a radial height of H1 and an annular diffuser having an axial length of L3, the downstream diffuser vane having a radial height of H1 and ... L3 ≧ 2.5×H1, L3≧3×H1

6. The electric blower according to claim 1, The electric blower is characterized in that the motor housing is made up of an upstream motor housing covering the upstream side of the stator core and a downstream motor housing covering the downstream side of the stator core, which are connected to each other so that the stator core is not exposed.

7. The electric blower according to any one of claims 1 to 6, An electric blower having an axial opening in either an upstream or downstream motor housing or in both.

8. An electric vacuum cleaner comprising the electric blower according to any one of claims 1 to 7.

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