Electric fan and electric vacuum cleaner with it

Abstract

This invention provides an electric fan capable of improving the cooling efficiency of an electric motor. The electric fan of this invention has a first axial diffuser fin (23) and a second axial diffuser fin (24) downstream of the impeller, which has two motor housings located on the impeller side and the reverse impeller side. An impeller-side housing (6) integral with the first axial diffuser fin (23) is fixed to the impeller-side motor housing (6) and arranged to cover the surrounding area. A reverse impeller-side housing (9) having the second axial diffuser fin (24) is arranged to cover the reverse impeller-side motor housing (10), and both motor housings have multiple openings arranged in the radial direction. The radial openings of the reverse impeller-side motor housing (10) serve as intake ports for cooling air flowing into the motor, and the radial openings of the impeller-side motor housing (6) serve as exhaust ports for cooling air flowing out of the motor.

Description

Technical Field

[0001] This invention relates to an electric fan and an electric vacuum cleaner having the same. Background Technology

[0002] In recent years, the demand for cordless or self-propelled electric vacuum cleaners has increased rapidly. To achieve sufficient power even when powered by low-voltage batteries, and to reduce vibration and noise, electric fans utilizing DC brushless motors are employed. Furthermore, miniaturization of the electric fan is also required to achieve miniaturization of the electric vacuum cleaner itself. Regarding the miniaturization of the electric fan, the outer diameter of the impeller can be reduced by increasing the speed of the electric fan. Therefore, there are cases where the speed of the brushless motor is approximately 50,000 revolutions per minute or more. For example, the structure disclosed in Patent Document 1 is an example of such an electric fan.

[0003] Patent document 1 describes: "The air supply device 1 includes: an impeller 10 that rotates about a vertically extending central axis C; an electric motor 20 disposed below the impeller 10 and having a stator 24 to rotate the impeller; an electric motor housing 21 that houses the stator; and a fan housing 2 that houses the impeller and the electric motor housing and forms a first flow path 5 in the gap with the electric motor housing. The upper part of the fan housing covers the upper part of the impeller and has an air intake 3 that opens in the vertical direction. An exhaust port 4 that communicates with the air intake via the first flow path is provided at the lower part of the fan housing. An inlet 21a that penetrates in the radial direction and communicates with the first flow path is provided in the electric motor housing at a position lower than the upper surface of the stator fixed to the inner surface of the electric motor housing. The electric motor housing has a second flow path 6 that extends upward from the inlet and communicates with a space above the stator."

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-105269 Summary of the Invention

[0007] The technical problem that the invention aims to solve

[0008] However, the operating airflow of vacuum cleaners varies significantly due to factors such as filter clogging caused by dust and the material of the floor being cleaned. Therefore, vacuum cleaners strive for motors with strong suction power across a wide airflow range. Furthermore, the ease of use of vacuum cleaners necessitates miniaturization and weight reduction of the motor. This results in a reduced heat dissipation area, increased heat density within the motor, and a need for improved cooling performance for the motor and bearings.

[0009] Furthermore, while winged diffusers offer excellent pressure recovery at the design airflow rate, their performance deteriorates at off-design airflow rates because the inlet angle of the diffuser fins does not align with the inflow angle of the airflow towards the diffuser. Therefore, it's possible for a vacuum cleaner's suction power to be high at the design airflow rate but low at off-design airflow rates.

[0010] Battery-powered vacuum cleaners, such as cordless or self-propelled models, have lower power consumption and maximum airflow due to battery capacity limitations. Therefore, when the filter becomes clogged, the dust collection capacity decreases, leading to reduced suction power. Furthermore, battery-powered vacuum cleaners like cordless or self-propelled models require small size and lightweight construction, necessitating a motor that balances strong suction power across a wide airflow range with a compact design.

[0011] In the prior art described in Patent Document 1, a first flow path is formed in the gap between the fan housing and the motor housing. The upstream side of the first flow path is connected to the impeller, and an exhaust port is formed on the downstream side of the flow path. An inlet communicating with the first flow path is provided on the peripheral wall of the motor housing. The inlet is located below the upper surface of the stator, which is fixed to the inner surface of the motor housing, and extends radially through it. In addition, the motor housing has a second flow path extending upward from the inlet and communicating with a space above the stator. The lower end of the second flow path is closed, and all airflow entering the second flow path flows upward.

[0012] In this way, the flow of the first flow path is branched, flowing from the inlet into the second flow path, cooling the stator, flowing near the ball bearings on the impeller side located above the stator, then cooling the sliding bearings on the reverse impeller side, and exhausting to the outside of the motor without merging with the first flow path.

[0013] However, since the airflow in the first flow path flows axially, it needs to bend 90 degrees to flow radially into the inlet. Furthermore, the second flow path flows upwards while radially flowing to cool the ball bearings on the impeller side, then bends 90 degrees to flow towards the reverse impeller side to cool the sliding bearings before exhausting the air. Therefore, there is a problem of large pressure loss in the flow paths, reduced airflow into the second flow path, and insufficient cooling of the stator and bearings inside the motor.

[0014] Furthermore, the downstream airflow from the inlet of the first flow path is reduced due to the airflow flowing into the second flow path. While the winged diffuser provides excellent pressure recovery at the design airflow, its performance deteriorates when the airflow is lower than the design airflow, potentially reducing the suction power of the vacuum cleaner.

[0015] The present invention is proposed to solve the above-mentioned problems. Its main objective is to provide an electric fan and an electric vacuum cleaner that achieves a small, lightweight and highly reliable structure, and can fully cool the operating motor and bearings, thereby achieving high efficiency in a wide air volume.

[0016] Technical solutions for solving the problem

[0017] To achieve the above objectives, the present invention provides an electric fan and an electric vacuum cleaner equipped with the electric fan. The electric fan is characterized by comprising: an electric motor having: a rotating rotor core; a stator core and windings located on the outer periphery of the rotor core; and two motor housings disposed on an impeller side and an anti-impeller side (opposite sides of the impeller) with a portion of the outer periphery of the stator core exposed; and a fan having a first axial diffuser vane and a second axial diffuser vane axially downstream of the impeller. The electric motor and the fan are formed by separate assemblies, and the impeller-side housing, integral with the first axial diffuser vane, is fixed to the impeller-side motor housing. Furthermore, the motor housing on the impeller side is arranged such that it covers the periphery of the motor housing on the impeller side from upstream to approximately the center along the long axis direction. The reverse impeller side housing, having second axial diffuser vanes, is also arranged such that it covers the reverse impeller side motor housing from approximately the center to downstream along the long axis direction. Both motor housings have multiple openings arranged radially. The radial openings of the reverse impeller side motor housing serve as intake ports for cooling air to flow into the motor, and the radial openings of the impeller side motor housing serve as exhaust ports for cooling air to flow out of the motor. Other configurations will be described later.

[0018] Invention Effects

[0019] According to the present invention, a small, lightweight and highly reliable structure can be realized, and the cooling efficiency of the operating electric motor can be improved, enabling high efficiency in a wide air volume range. Attached Figure Description

[0020] Figure 1A This is a perspective view of an electric vacuum cleaner equipped with an electric fan for use in a stick-type configuration.

[0021] Figure 1B This is a side view of an electric vacuum cleaner equipped with an electric fan for handheld use.

[0022] Figure 2 This is a longitudinal cross-sectional view of the main body of a vacuum cleaner equipped with an electric fan according to the implementation method.

[0023] Figure 3A This is an external view of the electric fan in the implementation method.

[0024] Figure 3B This is a longitudinal cross-sectional view of the electric fan in the implementation method.

[0025] Figure 4A It is a 3D diagram of the impeller.

[0026] Figure 4B This is a cross-sectional view of the impeller.

[0027] Figure 5A This is a front view of the casing with the first axial diffuser blades, viewed from the impeller side.

[0028] Figure 5B It is a cross-sectional view of the shell with the first axial diffuser blade.

[0029] Figure 5C It is a partial cross-sectional view of the shroud with a portion of the first axial diffuser blades removed.

[0030] Figure 6A This is a front view of the casing with the second axial diffuser blades, viewed from the impeller side.

[0031] Figure 6B It is a cross-sectional view of the shell with a second axial diffuser fin.

[0032] Figure 6C It is a partial cross-sectional perspective view of a shroud with a portion of the second axial diffuser blades removed.

[0033] Figure 7A This is a 3D view of the motor section.

[0034] Figure 7B This is a longitudinal cross-sectional view of the motor section.

[0035] Figure 7C It is a perspective view of the motor section cut through a horizontal cross-section located above the radial opening of the motor housing on the reverse impeller side.

[0036] Figure 8 This is a longitudinal cross-sectional view of the electric fan according to the second embodiment of the present invention. Detailed Implementation

[0037] Hereinafter, embodiments of the present invention (hereinafter referred to as "this embodiment") will be described in detail with reference to the accompanying drawings. Furthermore, the drawings are merely schematic representations to provide a sufficient understanding of the present invention. Therefore, the present invention is not limited to the illustrated examples. Additionally, in the drawings, common or identical components are labeled with the same reference numerals, and repeated descriptions of them are omitted.

[0038] <Structure of an electric vacuum cleaner equipped with a motorized fan>

[0039] The following is for reference Figure 1A , Figure 1B ,and Figure 2 The structure of the electric vacuum cleaner 400 equipped with the electric fan 200 in this embodiment will be described. Figure 1A This is a perspective view of the electric vacuum cleaner 400 equipped with an electric fan 200 in this embodiment when used in a stick mode. Figure 1B This is a side view of the 400 electric vacuum cleaner being used in a handheld manner. Figure 2 This is a longitudinal cross-sectional view of the vacuum cleaner body 410 of the electric vacuum cleaner 400.

[0040] Furthermore, in this embodiment, the description assumes that the electric fan 200 is mounted on a rechargeable vacuum cleaner 400 that can be used in both stick and handheld modes. However, the electric fan 200 can also be mounted on various types of vacuum cleaners 400, such as stick-only or handheld-only models.

[0041] like Figure 1A As shown, the electric vacuum cleaner 400 includes: a dust collection chamber 401 for collecting dust; and a vacuum cleaner body 410 that houses an electric fan 200 for generating the suction airflow required for dust collection (see reference). Figure 2 ); a telescopic tube 402 retractably provided relative to the vacuum cleaner body 410; a handle portion 403 provided at one end of the telescopic tube 402; and an electric fan 200 provided in the handle portion 403 (see reference). Figure 2 The switch part 404 of the switch.

[0042] exist Figure 1A In the example shown, the vacuum cleaner 400 is in a stick state, and the telescopic tube 402 is in an extended state. In the stick state, a suction port 405 is installed at the other end of the vacuum cleaner body 410, and the vacuum cleaner body 410 and the suction port 405 are connected by a connecting part 406.

[0043] On the other hand, Figure 1B In the example shown, the vacuum cleaner 400 is in a handheld state, with the telescopic tube 402 housed within the vacuum cleaner body 410, and the handle portion 403 positioned near the telescopic tube 402. In the handheld state, a handle portion 407, serving as a handle, is positioned on the upper surface of the vacuum cleaner body 410 between the handle portion 403 and the dust collection chamber 401. Furthermore, a suction nozzle 408 (gap nozzle) is installed at the other end of the vacuum cleaner body 410, and the vacuum cleaner body 410 and the suction nozzle 408 are connected via a connecting portion 406.

[0044] In this structure, in the vacuum cleaner 400, the electric fan 200 housed in the vacuum cleaner body 410 is activated by operating the switch 404 of the handle 403. Figure 2(Refer to) the operation, causing an airflow to be generated. The vacuum cleaner 400 draws air from the suction port 405 (refer to) Figure 1A ) or suction body 408 (refer to) Figure 1B Dust is sucked in and collected in the dust collection chamber 401 of the vacuum cleaner body 410 through the connection part 406.

[0045] like Figure 2 As shown, an electric fan 200 that generates suction force, a battery assembly 420 that supplies power to the electric fan 200, and a drive circuit 430 are installed inside the vacuum cleaner body 410. Furthermore, in Figure 2 In the example shown, the vacuum cleaner 400 is in a handheld state, and the suction nozzle 408 has been detached from the vacuum cleaner body 410.

[0046] From the suction body 405 (reference) Figure 1A ) or suction body 408 (refer to) Figure 1B The drawn-in air is transported through a flow path 440 provided in the vacuum cleaner body 410 to a dust collection chamber 401 located in front of the electric fan 200, where dust is collected. The air, after the dust has been separated in the dust collection chamber 401, is discharged to the outside through an exhaust port (not shown) formed in the vacuum cleaner body 410 via the electric fan 200 and the drive circuit 430.

[0047] <Structure of an electric fan>

[0048] The structure of the electric fan 200 will be described below with reference to Figures 3 to 7.

[0049] Figure 3A This is an exterior view of the electric fan 200. Figure 3B This is a longitudinal section view of the electric fan 200. Figure 4A It is a 3D diagram of the impeller. Figure 4B This is a cross-sectional view of the impeller. Figure 5A This is a front view of the impeller-side casing with the first axial diffuser blades, viewed from the impeller side. Figure 5B It is a cross-sectional view of the impeller-side casing with the first axial diffuser blades. Figure 5C The figure shows a portion of the shroud of the impeller-side casing with the first axial diffuser blades removed. Figure 6A This is a front view of the anti-impeller side casing with second axial diffuser blades, viewed from the impeller side. Figure 6B A cross-sectional view of the impeller-side casing with a second axial diffuser vane. Figure 6C It is a perspective view of a portion of the shroud of the anti-impeller side casing with the second axial diffuser blades removed. Figure 7A This is a 3D view of the electric motor. Figure 7B This is a longitudinal cross-sectional view of the electric motor. Figure 7CThis is a perspective view of the electric motor cut through a horizontal section located above the radial opening of the motor housing on the impeller side. Furthermore, in Figure 3B The text indicates the application of ring-shaped anti-vibration rubber 21 in the electric fan 200. Additionally, in... Figure 3B In China only Figure 3B The left side is represented by solid arrow α1 and dashed arrow α2 to indicate representative airflow.

[0050] like Figure 2 As shown, the electric fan 200 is installed inside the electric vacuum cleaner 400. At this time, the impeller 1 (refer to...) Figure 3B The suction port 405 faces the lower part of the vacuum cleaner 400 (see reference). Figure 1A ) or suction body 408 (refer to) Figure 1B The electric fan 200 is installed on the electric vacuum cleaner 400 in the direction of the electric fan 200.

[0051] As shown in Figures 3 to 7, the electric fan 200 has a motor unit 202 located radially inside the fan unit 201. The fan unit 201 has an impeller 1 (serving as a rotor), a first axial diffuser vane 23 on the impeller side, and a second axial diffuser vane 24, arranged from upstream of the airflow intake. An exhaust port 32 is located downstream of the second axial diffuser vane 24. The impeller-side housing 2 holds the first axial diffuser vane 23 and is mounted in a threaded hole 36 provided in the impeller-side motor housing 6 by a threaded fastener (e.g., a screw) 39. The reverse impeller-side housing 9 holds the second axial diffuser vane 24 and has an exhaust port 32 located downstream of the impeller-side housing 2. The motor unit 202 is located radially inside the impeller-side housing 2 and the reverse impeller-side housing 9. The impeller-side housing 2 is positioned to cover the impeller-side motor housing 6, and the reverse impeller-side housing 9 is positioned to cover a portion of the axial direction of the reverse impeller-side motor housing 10, with a portion of the opening 20 provided in the radial direction of the outer periphery of the reverse impeller-side motor housing 10 exposed. The impeller-side motor housing 6 holds the bearing 11 on the impeller 1 side of the motor section 202 in the axial direction. The reverse impeller-side motor housing 10 holds the bearing 12 on the reverse impeller side of the motor section 202 in the axial direction.

[0052] The impeller-side motor housing 6 and the reverse impeller-side motor housing 10 have the same shape, with multiple openings in the radial and axial directions of their outer periphery. The axial opening 34 of the reverse impeller-side motor housing 10 communicates with the outside, while the axial opening 33 of the impeller-side motor housing 6 is closed by the impeller-side housing 2. The impeller-side motor housing 6 has six openings in the circumferential direction, one in the radial direction (15) and the reverse impeller-side motor housing 10 has six openings (20). Furthermore, the openings 15 of the impeller-side motor housing 6 and 20 of the reverse impeller-side motor housing 10 are arranged so as not to overlap with the stator core 8 in the axial direction. Additionally, the openings 15 and 20 of each motor housing are arranged to overlap with the axial ends of the winding 17 in the axial direction. Moreover, the radial openings of each motor housing are evenly distributed in the circumferential direction, and the number of openings has a greatest common divisor of 3 with the number of blades of the second axial diffuser blade 24 on the reverse impeller 1 side. That is, the same flow field can be introduced into the opening 20 at 3 points in the circumferential direction, thereby reducing the circumferential temperature distribution. In addition, the greatest common divisor is greater than 2, preferably 3 or more, or the same as the number of openings.

[0053] On the side of the electric fan 200, a first flow path 18 is provided, passing through the impeller 1 and the first axial flow diffuser vane 23 and the second axial flow diffuser vane 24 on the side of the impeller 1. The first flow path 18 is the suction inlet 405 on the lower side of the electric vacuum cleaner 400 (see reference). Figure 1A ) or suction body 408 (refer to) Figure 1B The second flow path 19 is the flow path through which air flows by the attraction of the airflow. Air flows into the interior of the motor section 202 from the radial opening 20 and the axial opening 34 of the motor housing 10 on the impeller side, flows towards the impeller 1 side inside the motor section 202, and flows towards the exhaust port 32 side of the impeller side housing 9 from the radial opening 15 of the motor housing 6 on the impeller side, through the gap formed between the impeller side housing 2, the impeller side housing 9 and the motor housing 6 and the motor housing 10 on the impeller side, towards the exhaust port 32 side of the impeller side housing 9.

[0054] The first flow path 18 and the second flow path 19 merge at the axial end 9c of the inner wall 9a of the impeller-side housing 9. Furthermore, the axial end 9c is located approximately halfway along the axial dimension of the second axial diffuser vane 24. By merging the first flow path 18 and the second flow path 19 at the axial end 9c, the Venturi effect generated by the main flow of the second axial diffuser vane 24 induces flow within the second flow path 19, drawing cooling air into the motor from the opening 20 and the axial opening 34 of the impeller-side motor housing 10. This improves the cooling performance of the motor section 202 and increases the efficiency of the electric fan 200 over a wide operating range. Furthermore, the axial end 9c can be approximately less than halfway along the axial dimension of the second axial diffuser vane 24, or it can extend to the trailing edge of the vane; however, to generate cooling air based on the Venturi effect, it is preferable to be located axially closer to the impeller 1 than the opening 20.

[0055] The second flow path 19 is located radially inward compared to the first flow path. Furthermore, the impeller-side motor housing 10 has an axial opening 34 and a radial opening 20. By increasing the opening size, the airflow generated by the Venturi effect can be increased, allowing for more efficient cooling of the motor interior when passing through the second flow path 19. Additionally, the opening 20 of the impeller-side motor housing 10 is located radially inward compared to the inner wall 9a of the impeller-side housing 9, thus easily ensuring the flow path area of ​​the second flow path 19 and enabling more efficient cooling of the motor section 202. Furthermore, a portion of the winding 17 is exposed from the opening 34 (not shown), connecting with the drive circuit 430 (see reference). Figure 2 Electrical connection. Here, the opening of the motor housing can be a quadrilateral hole, a round hole, or a hole of other shapes.

[0056] Figure 3B The impeller 1 shown in Figure 4 is covered by a metal sleeve 13 using a hub plate 26 made of thermoplastic resin. The impeller 1 is fixed by a fixing nut screwed into an internal thread threaded at the end of the rotating shaft 5. Furthermore, in this embodiment, the impeller 1, which serves as a rotor blade, is fixed to the rotating shaft 5 by providing an internal thread at the end of the rotating shaft 5 and using a fixing nut; however, it can also be fixed to the rotating shaft by pressing it in. Additionally, as... Figure 3B As shown in Figure 4, in this embodiment, the impeller 1 is a diagonal flow impeller, but it can also be a centrifugal impeller or an axial flow impeller.

[0057] <Electric Motor Section 202>

[0058] The structure of the motor section 202 in this embodiment will be explained in conjunction with the following description.

[0059] Figure 7A This is a perspective view of the motor section 202 from an angle. Figure 7B This is a longitudinal cross-sectional view of the motor section 202. Figure 7C This is a perspective view of the electric motor cut through a horizontal section above the radial opening 20 of the impeller-side motor housing 10. The motor section 202 includes a rotor core 7 and a stator core 8 disposed on its outer periphery. The rotor core 7 is housed within the two impeller-side motor housings 6 and the impeller-side motor housing 10, and fixed to the rotating shaft 5. The stator core 8 has an annular yoke 8b, pole portion 8c, and tooth portion 8d. A slot 8e is formed in the space surrounded by the yoke 8b, pole portion 8c, and tooth portion 8d for insertion of the winding 17. The pole portion 8c extends radially inward from the inner periphery of the yoke 8b towards the rotor core 7, and the winding 17 is wound around the pole portion 8c via a winding frame 25. The winding 17 and the drive circuit 430 (see reference) provided in the electric fan 200... Figure 2 Electrical connection. In addition, while winding 17 uses copper wire, a smaller and lighter electric fan can be provided by using aluminum wire or a composite material with copper material around the aluminum wire.

[0060] The rotor core 7 has a rare-earth-based bonded magnet. The rare-earth-based bonded magnet is made by mixing rare-earth-based magnetic powder with an organic binder. Examples of rare-earth-based bonded magnets include samarium iron nitride magnets and neodymium magnets. The rotor core 7 can be integrally formed with the rotating shaft 5 or fixed to the rotating shaft 5. Furthermore, the operating speed of the electric fan 200 is approximately 50,000 to 200,000 revolutions per minute. In this embodiment, a permanent magnet is used for the rotor core 7, but it is not limited to this; a reluctance motor, a type of commutatorless motor, can also be used.

[0061] The impeller 1 side of the rotor core 7 has a bearing 11. A bearing 12 is located on the opposite side of the rotor core 7, opposite to the direction of the rotation shaft 5 of the bearing 11. The rotation shaft 5 is rotatably supported by the bearing 11 on one side and the bearing 12 on the other side. The impeller-side motor housing 6 supports the bearing 11, and the reverse impeller-side motor housing 10 supports the bearing 11. The impeller-side motor housing 6 and the reverse impeller-side motor housing 10 are made of metal, preferably aluminum alloy, which improves cooling performance and reduces weight due to heat conduction. Alternatively, the motor housing may not be made of metal but of resin. In the case of resin, cooling of the bearing can be promoted by providing a metal support between the bearing and the motor housing. Furthermore, the impeller-side motor housing 6 and the reverse impeller-side motor housing 10 may also be made of aluminum alloy or steel.

[0062] Spacers 16 are provided on the rotor core 7 side of bearings 11 and 12 for axial positioning of the bearings. Furthermore, regarding the adjustment of the imbalance of the rotating body, the imbalance is minimized by providing a magnet cover on the outer periphery of the magnet and a resin-made balance adjustment member 14 at the end of the magnet. This reduces the noise and vibration of the electric fan 200.

[0063] The impeller-side motor housing 6 and the reverse impeller-side motor housing 10 have the same shape and are arranged to clamp the stator core 8 in the axial direction. The outer periphery of the stator core 8 overlaps the inner wall of the motor housing in the axial direction and is assembled by bonding or pressing. The stator core 8 contacts the two impeller-side motor housings 6 and the reverse impeller-side motor housing 10, and has an exposed portion 8a at approximately the center of the stator core 8, where a portion of the outer periphery of the yoke 8b protrudes from the motor housing. By forming such a stator core 8 and motor housing structure, the heat generated by the stator core 8 is facilitated by the heat conduction of the impeller-side motor housing 6 and the reverse impeller-side motor housing 10, as well as the exposed portion 8a disposed in the second flow path 19, thus promoting the cooling of the stator core 8 and achieving low-loss cooling with high heat density. By using motor housings with the same structure, both cost reduction and improved cooling performance can be achieved.

[0064] The opening 20, located in the radial direction of the impeller-side motor housing 6, is positioned circumferentially between the pole portions 8c of the stator core 8. Specifically, the opening 20 is positioned radially in the slot portion 8e of the stator core 8, ensuring that its axial position does not overlap with the stator core 8. This allows cooling air to easily flow into the opening 20. Furthermore, since the cooling air blows onto the high-heat-generating winding 17 in the motor section 202, the cooling performance of the motor section 202 is improved. In this embodiment, six slot portions 8e and six openings 20 are formed, resulting in three openings in total. This improves the rigidity of the impeller-side motor housing 6 and the impeller-side motor housing 10, which is beneficial for reducing vibration and noise. Additionally, a winding frame 25 for winding the winding 17 is positioned radially inside the opening 20. Because cooling air flows into the motor section 202 from both ends of the winding frame 25, the airflow velocity is increased, effectively cooling the winding 17. Furthermore, since cooling air also flows into the motor section 202 from the axial opening 34, sufficient airflow can be obtained to cool the winding 17, stator core 8, and bearings 11 and 12.

[0065] The radial opening 20 of the impeller-side motor housing 10 and the radial opening 15 of the impeller-side motor housing 6 are located at different positions in the circumferential direction. Even though the axial opening 33 of the motor housing 6 is closed by the impeller-side housing 2, since no winding frame 25 is arranged inside the radial opening 15 of the impeller-side motor housing 6, the opening area of ​​the opening 15 can be sufficiently ensured, and the cooling of each part of the motor section 202 can be reduced, resulting in a highly reliable electric fan.

[0066] Next, the circumferential positions of the first axial diffuser vane 23 on the impeller 1 side shown in Figure 5 and the second axial diffuser vane 24 on the reverse impeller 1 side shown in Figure 6 will be explained. Protrusions 35 are provided at three circumferential locations on the outer periphery of the impeller-side housing 2. Claws 22 provided on the outer periphery of the reverse impeller-side housing 9 are fitted into and connected to the protrusions 35 of the impeller-side housing 2. Furthermore, the number of vanes of the first axial diffuser vane 23 on the impeller 1 side, the number of claws 22 at the end of the reverse impeller-side housing 9, and the number of protrusions 35 on the impeller-side housing 2 are configured such that the greatest common divisor of the number of vanes and the number of protrusions 35 is 3. Thus, the circumferential positions of the first axial diffuser vane 23 and the second axial diffuser vane 24 on the impeller 1 side are predetermined circumferential positions, enabling improved mass production capabilities. In addition, the greatest common divisor of the number of fins and the protrusion 35 only needs to be greater than 2. When the number of protrusions is used to construct the diffuser fins, the circumferential position of each diffuser fin is determined, and the mass production capability during assembly is optimal.

[0067] Figure 3B The fan housing 3 covering the impeller 1 shown is engaged and fixed to the impeller-side housing 2 by inserting the lower end 3a of the fan housing 3 into the fitting portion 28 (see Figure 5) of the impeller-side housing 2. Furthermore, a mounting portion is provided in the vacuum cleaner body 410 of the fan housing 3. Figure 3B The vibration damping rubber 21 is shown. By providing the vibration damping rubber 21, the vibration of the electric fan 200 is suppressed, and air leakage between the fan housing 3 and the mounting part of the vacuum cleaner body 410 is prevented, thereby achieving low noise and high efficiency.

[0068] The impeller-side housing 2 has a through hole 40 for fixing to the impeller-side motor housing 6, and is fixed to the impeller-side motor housing 6 using a fixing thread 39. The electric fan 200 is assembled by inserting the impeller-side housing 2 from the impeller 1 side through the threaded hole 36 provided in the impeller-side motor housing 6 of the separately assembled motor unit 202, and then fixing it using the fixing thread 39. Next, the impeller 1 is inserted into the rotating shaft 5 of the motor and fixed with an internal thread. Then, the fan housing 3 is inserted into the fitting portion 28 of the impeller-side housing 2, and the fan housing 3 and impeller-side housing 2 are bonded together using adhesive. The motor assembly, which is integral with the fan housing 3, is assembled by fitting the claw portion 22 and the protrusion 35 of the reverse impeller-side housing 9. Furthermore, by applying adhesive to the fitting portion 37 of the reverse impeller-side housing 9 and fixing it, the impeller-side housing 2 and the reverse impeller-side housing 9 are integrated, which can suppress the generation of vibration and noise. In this way, the assembly of the motor and the fan is carried out from the upstream direction of the impeller, which improves the assemblability during mass production.

[0069] In addition, the fitting part 28 between the fan housing 3 and the impeller side housing 2 is provided with some gaps in the axial and circumferential directions in a way that allows the impeller core to shift. By adjusting during assembly, the shaft core of the impeller 1 and the fan housing 3 can be adjusted, thereby achieving high efficiency and improved mass production.

[0070] Here, as Figure 3B As shown, the axial length Lm of the motor, which connects the upper and lower ends of the motor housing forming the outer periphery, is approximately the same as the axial length Ld of the diffuser from the impeller outlet to the exhaust port, and is shorter than the axial length Lf of the fan from the fan inlet to the exhaust port. Furthermore, the ratio of the fan axial length Lf to the motor axial length Lm is approximately 3:2, and the fan axial length Lf and the motor axial length Lm are arranged to overlap axially. By implementing this structure, the Venturi effect at the diffuser outlet can be fully utilized, the cooling airflow into the motor can be introduced with low loss, and a small and highly efficient electric fan can be achieved.

[0071] Furthermore, in order to maximize the Venturi effect generated by the flow in the first flow path 18, which is a feature of this embodiment, it is preferable to have a small difference in the maximum diameter of the flow path formed by the inner wall 2a of the housing 2 of the first flow path 18 and the second flow path 19 and the impeller-side motor housing 6. In this structure, in order to take in cooling air utilizing the Venturi effect, the maximum diameter Rd of the flow path of the impeller-side housing 9 with the second axial diffuser vanes (the diameter of the outer wall 9b of the impeller-side housing 9 on the impeller-side motor housing 10 side) is formed to be approximately 1.5 times the outer diameter Rm of the outer periphery of the impeller-side motor housing 10. In addition, the smaller the ratio of the maximum diameter Rd of the flow path of the impeller-side housing 9 with the second axial diffuser vanes 24 to the outer diameter Rm of the outer periphery of the impeller-side motor housing 10 is than approximately 1.5 times, the more effectively the Venturi effect can be obtained, and a small and highly efficient electric fan can be realized. Furthermore, in this embodiment, a structure with a second axial diffuser fin 24 is described, but as long as the Venturi effect can be obtained, the flow path can be annular regardless of whether there is a second axial diffuser fin 24.

[0072] The first axial diffuser vane 23 on the impeller 1 side is designed so that the flow exiting the impeller 1 is approximately at the same angle as the vane inlet, reducing pressure loss. Therefore, by utilizing the first axial diffuser vane 23, the rotational velocity component of the airflow can be reduced, improving the diffuser effect and increasing fan efficiency. Furthermore, the second axial diffuser vane 24, located axially downstream of the first axial diffuser vane 23, further reduces the rotational velocity component of the airflow exiting the first axial diffuser vane 23. This further reduces the deceleration of airflow in the direction of the rotation axis 5, further improving fan efficiency.

[0073] <Airflow within the electric fan 200>

[0074] Next, the airflow within the electric fan 200 will be explained.

[0075] drive Figure 3B When the impeller 1 is rotated by the motor unit 202 shown, air flows in from the intake port 4 of the fan housing 3 and into the impeller 1. In the case of a diagonal-flow impeller, the incoming air is pressurized within the impeller 1 while a radial component is imparted to the airflow drawn in from the direction of the rotation axis 5, resulting in a flow inclined from the direction of the rotation axis 5. Thus, the airflow exits the impeller 1 at the impeller outlet 1a as an airflow having both a rotational component and a component from the direction of the rotation axis 5.

[0076] The airflow exiting from the impeller 1 flows along the first axial diffuser vane 23 and the second axial diffuser vane 24 as it passes through them, thereby reducing the rotational velocity component of the airflow. Furthermore, the axial end 9c (lower end of the inner wall) of the reverse impeller-side housing 9 is located upstream of the trailing edge 24b of the second axial diffuser vane 24 (the trailing edge 24b of the second axial diffuser vane 24 protrudes from the inner wall of the second axial diffuser vane 24), thus widening the flow path radially inward in the rear half of the second axial diffuser vane 24. This results in a radially inward flow in the rear half of the second axial diffuser vane 24, leading to exhaust (the airflow expands in the direction without the inner wall). This radially inward flow promotes the inflow into the opening 20 of the reverse impeller-side motor housing 10. Additionally, the first flow path 18... Figure 3B The solid arrow α1 indicates the flow path from the intake port 4 of the fan housing 3 to the exhaust port 32 of the reverse impeller side housing 9.

[0077] Regarding the second flow path 19, due to the high outlet velocity of the second axial diffuser vane 24, a flow towards the outlet of the second axial diffuser vane 24 is generated within the second flow path due to the Venturi effect. The flow towards the outlet of the second axial diffuser vane 24 in the second flow path is achieved by drawing in airflow from the opening 20 of the impeller-side motor housing 10, passing near the bearing 12 on the impeller side inside the motor, and between the circumferentially arranged windings 17, thereby cooling the impeller-side bearing 12 and windings. Furthermore, the airflow passing between the windings passes around the bearing 11 on the impeller 1 side and through the opening 15 of the impeller-side motor housing 6, flowing axially downstream (to the outlet of the second axial diffuser vane 24) in the radial gap between the impeller-side motor housing 6 and the inner wall 2a of the impeller-side housing 2, merging with the first flow path. Furthermore, the stator core 8 is cooled with low loss because the cooling air passes through the radial gap between the impeller-side motor housing 6 and the inner wall 2a of the impeller-side housing 2.

[0078] Near the second axial diffuser vane 24, the first flow path and the second flow path merge, thereby enabling efficient utilization of the Venturi effect to cool the inside of the motor. That is, when the cooling air for the motor is drawn in, since there is no change in the flow direction caused by the structure, the fan efficiency can be maintained at a high level even at non-design points, achieving high efficiency over a wide operating range.

[0079] <Fan Unit 201>

[0080] Next, the structure of the fan unit 201 in the embodiment will be described.

[0081] Figure 4A This is a perspective view of the impeller 1 in the embodiment. Figure 4BThis is a cross-sectional view of impeller 1. Figure 5A This is a front view of the impeller-side housing 2 with the first axial flow diffuser blade 23 on the impeller side, viewed from the impeller 1 side. Figure 5B It is a longitudinal section view of the impeller-side casing 2 with the first axial diffuser blade 23. Figure 5C It is a partial cross-sectional view of the shroud with a portion of the first axial diffuser blades removed. Figure 6A This is a front view of the anti-impeller side casing 9 with the second axial flow diffuser blades 24, viewed from the impeller 1 side. Figure 6B It is a longitudinal section view of the impeller-side housing 9 with the second axial diffuser blade 24. Figure 6C This is a partial cross-sectional perspective view of the impeller-side casing 9, viewed from the outer periphery, after a portion of the shroud with the second axial diffuser blades 24 has been removed. Furthermore, Figure 5C and Figure 6C To show the shapes of the first axial diffuser fin 23 and the second axial diffuser fin 24, the view shown is a partial cross-sectional view with the shield removed.

[0082] <Impeller 1>

[0083] First, using Figure 4A , Figure 4B The impeller 1 of the rotor according to an embodiment of the present invention will be described. The impeller 1 is composed of a hub plate 26 and a plurality of blades 27. The hub plate 26 and the blades 27 are integrally molded from engineering plastic and thermoplastic resin.

[0084] A protrusion 26a is provided on the back side of the hub plate 26. By rotating the impeller 1 and grinding the protrusion 26a, the balance of the impeller 1 can be corrected. This reduces the imbalance of the impeller 1, thereby reducing vibration and noise. In addition, a metal sleeve 13 is integrally formed on the back side of the hub plate 26. By using the sleeve 13, the unevenness of the fitting gap between the rotating shaft 5 and the impeller 1, which would occur without the sleeve, can be reduced. By reducing the imbalance of the impeller 1, vibration and noise can be reduced. Furthermore, by providing the metal sleeve 13 on the boss portion 29 of the impeller 1, heat emitted by the bearing 11 is transferred to the sleeve, thereby improving the cooling performance of the bearing 11 caused by the rotation of the sleeve 13.

[0085] The impeller 1 and the fan housing 3 are made of resin. The impeller 1 and the fan housing 3 are made of resin materials with different sliding properties. By running in a state where the impeller 1 is in contact with the fan housing 3, the material of either the impeller 1 or the fan housing 3 is ground, which can minimize the gap between the impeller 1 and the fan housing 3.

[0086] In order to grind the resin of the fan housing 3 when the centrifugal stress during the operation of the impeller 1 causes a large amount of blade deformation, a material with a low Young's modulus is used for the fan housing 3. This minimizes the gap between the impeller 1 and the fan housing 3 during operation, thereby obtaining a high-efficiency electric fan.

[0087] Impeller 1 has a convex curved surface 29a on its outer periphery in the direction of rotation shaft 5. Figure 4B (The downward direction) inclined oblique flow impeller. Figure 4A , Figure 4B In the figure, impeller 1 is an open-type diagonal flow impeller without a shroud, but it can also be a centrifugal impeller regardless of whether it has a shroud or not.

[0088] Next, the fan unit 201 of the first embodiment will be described.

[0089] like Figure 3B As shown in Figures 5 and 6, the fan unit 201 of this embodiment is provided with 15 first axial diffuser vanes 23 arranged at equal intervals in the circumferential direction on the downstream side of the impeller 1. The first axial diffuser vanes 23 are disposed between the inner wall 2a and the outer wall 2b of the impeller-side housing 2 and are integrally formed with the impeller-side housing 2. Second axial diffuser vanes 24 are disposed between the inner wall 9a and the outer wall 9b of the reverse impeller-side housing 9 and are integrally formed with the reverse impeller-side housing 9. Furthermore, the number of vanes in the second axial diffuser vanes 24 is the same as that of the first axial diffuser vanes 23 on the impeller 1 side, consisting of 15.

[0090] Figure 5 shows the trailing edge 23b of the first axial diffuser blade 23 on the impeller 1 side and the leading edge 24a of the second axial diffuser blade 24 (see reference). Figure 6C The circumferential positions of the first axial diffuser vane 23 and the second axial diffuser vane 24 are approximately aligned in the circumferential direction. Improvement in efficiency on the low-volume side can be achieved by aligning the trailing edge 23b of the first axial diffuser vane 23 and the leading edge 24a of the second axial diffuser vane 24 in the circumferential direction. To improve efficiency on the high-volume side, a vane pitch (360° / number of blades Zd) of 15-50% is preferable.

[0091] Figure 3B As shown, the inner wall 2a (hub) of the first axial diffuser vane 23 is substantially the same as the inner wall 9a (hub) of the second axial diffuser vane 24. Preferably, the inner wall 2a of the first axial diffuser vane 23 and the inner wall 9a of the second axial diffuser vane 24 are in the same plane (flush). This is because, for example, if the inner wall 9a of the reverse impeller side casing 9 after the flow convergence is large (the diameter of the hub surface is large) and protrudes into the flow path, the losses of the first axial diffuser vane 23 and the second axial diffuser vane 24 increase.

[0092] like Figure 3B As shown, the inner wall 2a of the impeller-side housing 2 and the inner wall 9a of the reverse impeller housing 9 are provided without axial clearance. The outer wall 2b of the impeller-side housing 2 and the outer wall 9b of the reverse impeller-side housing 9 are connected by a fitting part 37 (see reference). Figure 6B Centering of housing 2 is performed using the claw portion 22 on the outer periphery of housing 9 on the impeller side (refer to...). Figure 6B The structure is fixed circumferentially and bonded together, making it easy to assemble and improving its mass production capability.

[0093] Figure 5A ~C shows the shape of the first axial diffuser vane 23 on the impeller 1 side in the height direction, which is inclined from the inner wall 2a to the outer wall 2b of the impeller-side housing 2 towards the anti-impeller 1 side (from the side away from the impeller 1) (see reference). Figure 3B It has an inclination from near the center in the radial direction to the outer periphery, and is curved in the height direction.

[0094] like Figure 5C As shown, the chord length of the first axial diffuser vane 23 on the impeller 1 side (the line connecting the leading edge 23a and the trailing edge 23b) on the shroud side is longer than that on the hub side (inner wall 2a side). Furthermore, regarding the chord length on the shroud side, since the wind speed is high on the shroud side of the impeller 1 outlet, a gentler shape is formed to suppress losses and achieve high efficiency. Additionally, by bending the first axial diffuser vane 23 in the height direction, secondary flows generated on the diffuser hub side (inner wall 2a side) of the airfoil (the surface of the first axial diffuser vane 23) and the hub surface (inner wall 2a) can be suppressed. Therefore, stripping inside the diffuser (the airfoil on the inner wall 2a side of the first axial diffuser vane 23 and the inner wall 2a) can be suppressed, achieving high efficiency.

[0095] As shown in Figure 6, the thickness of the second axial diffuser vane 24 (the thickness of the vane on the trailing edge side) increases as it moves towards the exhaust port 32, and is thicker than the thickness of the first axial diffuser vane 23 on the impeller 1 side (see Figure 5). Furthermore, the chord length of the second axial diffuser vane 24 (the line connecting the leading edge 24a and the trailing edge 24b) is approximately the same as the chord length of the first axial diffuser vane 23 on the impeller 1 side on the shroud side. By employing a larger chord length for the second axial diffuser vane 24, and as... Figure 6C The trailing edge 24b of the second axial diffuser blade 24, as shown, has a larger blade thickness, which can slow down the airflow, improve static pressure recovery, and achieve high efficiency.

[0096] Here, the shapes of the first axial diffuser blade 23 and the second axial diffuser blade 24 will be described.

[0097] The first axial diffuser wing 23 and the second axial diffuser wing 24 have an airfoil shape with a wing chord length (e.g., the straight-line length connecting the first axial diffuser wing 23 from the leading edge 23a to the trailing edge 23b) divided by the circumferential distance of the wing mounting interval, as shown in FIG. 5, resulting in a wing solidity (wing chord length / inter-wing pitch) of less than 1. Furthermore, if the wing solidity is less than 1, it can be manufactured using a mold structure formed in the direction of the rotation axis 5, enabling high efficiency and increased productivity.

[0098] Furthermore, the axial end 9c (lower end of the inner wall) of the second axial diffuser vane 24 is located upstream of the rear edge 24b of the second axial diffuser vane 24 (the rear edge 24b of the second axial diffuser vane 24 protrudes from the inner wall 9a of the second axial diffuser vane 24). This causes the flow path to widen radially inward in the rear half of the second axial diffuser vane 24, thereby generating radially inward flow and exhausting the air. This promotes the inflow into the opening 20 of the motor housing 10 on the impeller side, improving cooling performance. Additionally, the axial position of the rear edge 24b of the second axial diffuser vane 24 is located between the radial and axial directions of the opening 20 of the motor housing 10 on the impeller side. This improves the deceleration of the flow in the rotational direction generated by the second axial diffuser vane 24, increasing static pressure. Furthermore, the deflection generated by the vane generates radially inward flow towards the opening 20, further improving cooling performance.

[0099] That is, the electric fan 200 of the embodiment can maintain high efficiency over a wide operating range. Therefore, it is possible to provide an electric vacuum cleaner 400 with high suction power over a wide range (see Figure 1).

[0100] In one implementation method, as an example, Figure 3B The opening of the motor housing 10 on the impeller side shown has a radial opening 20 and an axial opening 34, but it can also be an opening in either direction, or it can be an inclined opening that has both radial and axial directions.

[0101] The electric fan 200 according to the above-described embodiment is characterized by comprising: a motor unit 202 having a rotating rotor core 7, a stator core 8 and winding 17 on the outer periphery of the rotor core 7, an impeller-side motor housing 6 and an impeller-side motor housing 10 disposed on the impeller 1 side and the reverse impeller side in such a way that a portion of the outer periphery of the stator core 8 is exposed; and a fan unit 201 having a first axial diffuser vane 23 and a second axial diffuser vane 24 having vanes in the circumferential direction downstream of the impeller 1, wherein the motor unit 202 and the fan unit 201 are formed as separate assemblies, and the impeller-side housing 2, which is integral with the first axial diffuser vane 23, is fixed to the impeller-side motor housing. 6. The impeller-side motor housing 6 is arranged from upstream to approximately the center position along the long axis direction to cover the periphery of the impeller-side motor housing 6. The reverse impeller-side housing 9, which has a second axial diffuser vane 24, is arranged from approximately the center to downstream along the long axis direction to cover the reverse impeller-side motor housing 10 on the impeller side. The two motor housings have a plurality of openings 15 and 20 provided in the radial direction. The radial opening of the reverse impeller-side motor housing serves as an intake port for cooling air to flow into the motor, and the radial opening of the impeller-side motor housing serves as an exhaust port for cooling air to flow out of the motor.

[0102] Therefore, a highly efficient, compact, lightweight, and reliable electric fan 200 with a wide airflow range can be provided. Consequently, a compact electric vacuum cleaner 400 with improved suction power over a wide airflow range can be obtained, capable of cooling the stator core 8, windings 17, and bearings 11 and 12 of the motor section 202.

[0103] <<Second Implementation Method>>

[0104] Next, the second embodiment will be utilized. Figure 8 Please provide an explanation.

[0105] Figure 8 This is a longitudinal cross-sectional view of the electric fan 200 according to the second embodiment of the present invention.

[0106] The electric fan 200 of the second embodiment differs from the electric fan 200 of the first embodiment. The second flow path passes through the axial opening 33 of the impeller-side motor housing 6 and through the axial gap flow path 30 formed by the impeller-side housing 2 and the impeller-side motor housing 6. Furthermore, the cooling air passing through the axial gap flow path 30 passes through the annular flow path 38 formed by the radial gap between the impeller-side motor housing 6 and the impeller-side housing 2. The airflow passing through the annular flow path 38 merges with the second axial flow diffuser vane 24 through the connecting gap 31 between the first axial flow diffuser vane 23 on the impeller 1 side and the second axial flow diffuser vane 24 on the reverse impeller 1 side.

[0107] Since the electric fan 200 has the same basic structure as the first embodiment described above, the same reference numerals are used for the same components, and their descriptions are omitted.

[0108] The airflow in the second flow path 19, formed by the axial gap flow path 30, the annular flow path 38, and the connecting gap 31, generates a flow from inside the motor through the connecting gap 31 to the inlet of the second axial diffuser vane 24 on the side of the impeller 1 due to the high wind speed and low static pressure at the inlet. This flow utilizes the Venturi effect. The airflow through the connecting gap 31 flows into the motor from the opening 20 or axial opening 34 of the impeller-side motor housing 10 on the impeller side of the impeller 1, passes through the motor interior, and then through the axial opening 33 of the impeller-side motor housing 6, and through the axial gap flow path 30 between the impeller-side housing 2 and the impeller-side motor housing 6. Subsequently, the cooling air passing through the axial clearance flow path 30 passes through the radial gap (annular flow path 38) between the impeller-side motor housing 6 and the impeller-side housing 2, and then through the connecting gap 31 connecting the first axial diffuser vane 23 on the impeller 1 side and the second axial diffuser vane 24 on the reverse impeller side, merging with the second axial diffuser vane 24. The airflow in the second flow path 19 is drawn into the interior of the motor section 202, thereby cooling the bearing 12 on the reverse impeller 1 side. In addition, the airflow in the second flow path 19 flows on the outer periphery of the stator core 8, thereby cooling the stator core 8, the winding 17, and the bearing 11 on the impeller 1 side, flowing to the connecting gap 31.

[0109] Alternatively, the second flow path structure without axial clearance flow path shown in the first embodiment can also be used. In this case, cooling air can flow through the radial opening 15 of the impeller-side motor housing 6 to the connecting gap 31, thus achieving motor cooling. Furthermore, the connecting gap 31 is formed by the inner wall 2a of the impeller-side housing 2 and the reverse impeller-side housing 9. The connecting gap 31 slopes axially towards the exhaust side as it flows from the outer periphery of the stator core 8 towards the second axial diffuser vane 24. Therefore, the airflow flowing in the connecting gap 31 can smoothly merge with the airflow flowing in the first flow path 18, achieving cooling and increased efficiency.

[0110] The airflow flowing from the connecting gap 31 into the first flow path 18 merges with the airflow pressurized by the impeller 1, flows to the second axial diffuser vane 24, and is exhausted from the exhaust port 32. Furthermore, the airflow through the second axial diffuser vane 24, together with the airflow from the impeller 1 through the first axial diffuser vane 23 and the airflow flowing from the second flow path 19 through the connecting gap 31, becomes the maximum airflow inside the electric fan 200.

[0111] At non-design points with lower airflow, the second axial diffuser vane 24 is prone to generating a trailing vortex at the trailing edge of the first axial diffuser vane 23, making the inlet airflow of the second axial diffuser vane 24 more complex. However, regarding the second axial diffuser vane 24 in this structure, the airflow from the connecting gap 31 merges with the first axial diffuser vane 23 on the impeller 1 side and flows to the second axial diffuser vane 24.

[0112] Therefore, even outside the design point, the airflow inside the second axial diffuser vane 24 increases. This helps suppress delamination inside the second axial diffuser vane 24, improving fan efficiency. Furthermore, the airflow from the opening 20 of the motor housing 10 on the reverse impeller side to the connecting gap 31 flows more on the high-volume side, where the airflow at the outlet of the first axial diffuser vane 23 is increased. Therefore, in this structure, fan efficiency on the high-volume side can be improved, achieving high efficiency over a wide operating range.

[0113] According to the electric fan 200 of the second embodiment described above, the electric fan includes: an electric motor having a rotating rotor, a stator core at the outer periphery of the rotor, windings, and an electric motor housing disposed in both the impeller side and the reverse impeller side, with a portion of the outer periphery of the stator core exposed; and a fan having a first axial diffuser vane and a second axial diffuser vane having circumferentially fins downstream of the impeller. The electric motor and the fan are formed by separate assemblies. The impeller-side housing, integral with the first axial diffuser vane, is fixed to the impeller-side electric motor housing and is arranged to cover the periphery of the impeller-side electric motor housing in the long axis direction from upstream to approximately the center position. The impeller-side housing having the second axial diffuser fins is arranged to cover the impeller-side motor housing from approximately the center to downstream in the long axis direction. The two motor housings have multiple openings in the radial direction. The inner wall of the impeller-side housing and the motor housing have a gap in the radial direction. The opening of the impeller-side motor housing is located downstream of the second axial diffuser fins. The impeller-side motor housing has an opening in the axial direction. There is a gap in the axial direction between the impeller-side motor housing and the impeller-side housing. A connecting flow path is provided between the impeller-side axial diffuser fins and the impeller-side axial diffuser fins.

[0114] Therefore, a highly efficient, compact, and lightweight electric fan 200 with a wide airflow range can be provided. Thus, a compact electric vacuum cleaner 400 with improved suction power across a wide airflow range can be obtained by cooling the stator core 8 and bearing 11 of the motor unit 202.

[0115] Furthermore, the present invention is not limited to the embodiments described above, but includes various modifications. For example, the embodiments described above are examples given in detail for ease of understanding of the present invention, and are not limited to having all the structures described. Additionally, a portion of the structure of one embodiment can be replaced with the structure of another embodiment, and structures of other embodiments can be added to the structure of one embodiment. Furthermore, other structures can be added, deleted, or replaced in relation to a portion of the structure of each embodiment.

[0116] Explanation of reference numerals in the attached figures

[0117] 1… Impeller, 1a… Impeller outlet, 2… Impeller side casing, 2a… Inner wall of impeller side casing (first axial diffuser), 2b… Outer wall of impeller side casing (first axial diffuser), 3… Fan casing, 3a… Lower end of fan casing, 4… Inlet, 5… Rotating shaft, 6… Impeller side motor casing, 7… Rotor core, 8… Stator core, 8a… Exposed part (outer periphery of yoke), 8b… Yoke, 8c… Pole part, 8d… Tooth part, 8e… Groove part, 9… Reverse impeller side casing, 9a… ...the inner wall of the impeller-side casing (hub surface of the second axial diffuser wing), 9b...the outer wall of the impeller-side casing (shroud surface of the second axial diffuser wing), 9c...the axial end of the impeller-side casing (lower end of the inner wall), 10...the motor casing on the impeller side, 11...the bearing (impeller-side bearing), 12...the bearing (impeller-side bearing), 13...the sleeve, 14...the balance adjustment component, 15...the opening (imeller-side motor casing opening), 16...the spacer, 17...the winding, 18...the first... Flow path, 19…Second flow path, 20…Mouth (opening of motor housing on the impeller side), 21…Anti-vibration rubber, 22…Claw (housing on the impeller side), 23…First axial diffuser vane (axial diffuser vane on the impeller side), 23a…Front edge, 23b…Rear edge, 24…Second axial diffuser vane (axial diffuser vane on the impeller side), 24a…Front edge, 24b…Rear edge, 25…Winding frame, 26…Hub plate, 26a…Protrusion, 27…Impeller blades, 28… ...Matching part, 29...Protrusion of impeller, 29a...Protrusion curved surface, 30...Axial clearance flow path, 31...Connecting clearance, 32...Exhaust port, 33...Axial opening of motor housing on impeller side, 34...Axial opening of motor housing on reverse impeller side, 35...Protrusion, 36...Threaded hole, 37...Matching part, 38...Annular flow path, 39...Fixed threaded part, 40...Through hole, 200...Electric fan, 201...Fan part, 202...Motor part, 400...Electric vacuum cleaner.

Claims

1. An electrically powered fan characterised in that, Comprising: a motor having a rotating rotor core; a stator core and a winding located at an outer peripheral portion of the rotor core; and two motor housings provided at an impeller side and a counter-impeller side in a manner that exposes a part of the outer peripheral portion of the stator core; and a blower having a first axial-flow diffuser fin and a second axial-flow diffuser fin downstream of the impeller in an axial direction, the motor and the blower are formed by a split assembly, the impeller-side housing integrated with the first axial-flow diffuser fin is fixed to the impeller-side motor housing, and is arranged in a manner that covers the periphery of the impeller-side motor housing from upstream to substantially the center position in the long axis direction of the impeller-side motor housing, the counter-impeller-side housing having the second axial-flow diffuser fin is arranged in a manner that covers the counter-impeller-side motor housing from substantially the center to downstream in the long axis direction of the impeller-side motor housing, the two motor housings have a plurality of opening portions provided in a radial direction, the radial-direction opening of the counter-impeller-side motor housing serves as an air intake port for air flowing into the motor for cooling, and the radial-direction opening of the impeller-side motor housing serves as an air exhaust port for air flowing out of the motor for cooling.

2. The electric blower according to claim 1, wherein: the radial-direction opening of the counter-impeller-side motor housing is different in position from the radial-direction opening of the impeller-side motor housing in a circumferential direction.

3. The electric blower according to claim 1 or 2, wherein: the stator core has a ring-shaped yoke portion, a pole portion, and a tooth portion, a slot portion for insertion of the winding is formed using a space surrounded by the yoke portion, the pole portion, and the tooth portion, the radial-direction opening of the counter-impeller-side motor housing is provided at positions opposite in the radial direction in the slot portion.

4. The electric blower according to any one of claims 1 to 3, wherein: the impeller-side motor housing and the counter-impeller-side motor housing are the same shape.

5. The electric blower according to claim 4, wherein: the motor housing is provided with a plurality of openings in the radial direction and the axial direction.

6. The electric blower according to any one of claims 1 to 5, wherein: the greatest common divisor of the number of radial-direction openings of the motor housing and the number of vanes of the second axial-flow diffuser fin is 3, and the number of radial-direction openings is equal to or greater than the greatest common divisor.

7. An electrical vacuum cleaner characterised in that Having: the electric blower according to any one of claims 1 to 6; a dust collecting chamber for collecting dust; a handle portion as a handle for operation; and a switch portion that performs switching of a power source.

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