JP6758243B2 - Electric blower and vacuum cleaner equipped with it - Google Patents

Description

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

A conventional blower is disclosed in Japanese Patent No. 5903756 (Patent Document 1).

This Patent Document 1 states, "A centrifugal compressor for a vacuum cleaner, which has an impeller and a diffuser, operates between a low flow rate and a high flow rate, and the fluid flows at the low flow rate. It flows out from the impeller at the first flow angle, flows out from the impeller at the second flow angle at the high flow rate, and the difference between the first flow angle and the second flow angle is at least 20. The number of blades of the radial vanes is 15 in order for the diffuser to have multiple radial vanes and to perform positive pressure recovery without causing stall between the low and high flow rates. ~ 20, the solidity of the radial vane is 0.6 to 0.8, the radius ratio from the vane inlet to the impeller exit of the radial vane is less than 1.5, and the impeller. Is a centrifugal compressor that rotates at a speed exceeding 80 krpm at both the low flow rate and the high flow rate. "

Japanese Patent No. 5903756

Since the operating air volume of an electric vacuum cleaner changes greatly depending on operating conditions such as clogging of a filter and the material of the floor to be cleaned, an electric blower having a strong suction force in a wide air volume range is required. Further, the blade passing frequency noise obtained by the product of the number of blades of the impeller and the number of revolutions is related to the sound quality during operation, and its reduction is required.

A diffuser with blades can perform excellent pressure recovery at a design point air volume, but at a non-design point air volume, the diffuser performance deteriorates due to the mismatch between the inlet angle of the diffuser blades and the inflow angle of the air flow into the diffuser. Therefore, the suction power of the vacuum cleaner is high at the design point air volume, but there is a problem that it decreases at the non-design point air volume.

A vacuum cleaner driven by a battery (secondary battery) such as a cordless stick type or an autonomous driving type has a small power consumption of an electric blower and a small maximum air volume. Therefore, there is a problem that the dust transporting ability is lowered when the filter is clogged, and the suction power of the vacuum cleaner is lowered. Furthermore, a cordless stick type or battery-powered vacuum cleaner is required to be small and lightweight, and the electric blower mounted on the vacuum cleaner has a strong suction force over a wide air volume range and is compact. At the same time, it is required that the blade passing frequency noise during operation is small.

Patent Document 1 states that "the diffuser has a plurality of radial vanes, and the number of blades of the radial vanes is increased in order to perform positive pressure recovery without causing stall between the low flow rate and the high flow rate. It is 15 to 20, the solidity of the radial vane is 0.6 to 0.8, and the radial ratio from the vane inlet to the impeller exit of the radial vane is less than 1.5. " Patent Document 1 describes a centrifugal compressor equipped with a diffuser. The diffuser mounted on the centrifugal compressor provides positive pressure recovery that does not cause stall within the operating range. There is a description that the solidity should be in the range of 0.6 to 0.65. Here, the solidity is a value obtained by dividing the chord length of the diffuser blade by the circumferential distance (mounting interval) from the adjacent blades at the diffuser blade inlet radius.

Since the above centrifugal compressor has a small solidity of 0.8 or less, a wide operating range can be obtained, but it is considered that there is room for improvement in the efficiency of the blower. In addition, if the solidity is small, the chord length will be small, so unless the maximum thickness of the wing is set large for resin molding, the resin will not flow easily during molding, and short shots and sink marks will easily occur. It may cause variation. Further, if the maximum thickness of the blade is increased, the drag force of the blade is increased and the blower efficiency is lowered.

An object of the present invention is to solve the above problems, and in addition to improving efficiency, it is possible to improve sound quality by reducing mass productivity, driving noise, and blade passing frequency noise. That is, a compact and lightweight electric blower with high efficiency in a wide air volume range, low noise and blade passing frequency noise, and good sound quality is provided while suppressing performance variations during molding and mass production, and a small size with improved suction power in a wide air volume range. The purpose is to provide a vacuum cleaner with low driving noise and good sound quality.

In order to solve the above problems and to achieve the above object, for example, the configuration described in the claims is adopted.

The present invention includes a large number of means for solving the above problems. For example, an electric motor provided with a rotor and a stator, a housing having an opening at one end for accommodating the electric motor, and the rotor. A plurality of rotary shafts provided, a rotary blade fixed to the rotary shaft, a partition plate arranged on the electric motor side of the rotary blade, and a plurality of on the outer peripheral portion of the rotary blade provided on the opening side of the housing. The diffuser blade is provided with a fan casing covering the diffuser blade, the diffuser blade forms a throat portion by adjacent blades, and the throat portion is formed on the trailing edge side of the center of the chord length of the adjacent blade, and the diffuser The line connecting the front edge of the blade and the center of rotation has 15 to 17 diffuser blades without contacting the adjacent diffuser blades, and the inner surface of the fan casing and the circular outer peripheral end of the partition plate. The area of the annular flow path formed between the fan casings is set to be larger than the outlet area of the centrifugal impeller, and the end of the fan casing on the motor portion side is the end of the housing on the blower portion side. This is achieved by fitting and connecting to the parts.

According to the present invention, in addition to high efficiency, mass productivity, reduction of driving noise, and reduction of blade passing frequency noise enable improvement of sound quality. That is, a compact and lightweight electric blower with high efficiency in a wide air volume range, low noise and blade passing frequency noise, and good sound quality is provided while suppressing performance variations during molding and mass production, and a small size with improved suction power in a wide air volume range. Moreover, it is possible to provide an electric vacuum cleaner having a low driving noise and good sound quality.

Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is external drawing of the electric blower in 1st Embodiment of this invention. It is a vertical sectional view of the electric blower in 1st Embodiment of this invention. (A) is a perspective view of the centrifugal impeller according to the first embodiment of the present invention, and (b) is a vertical sectional view of the centrifugal impeller. It is a figure which shows the blower part in 1st Embodiment of the invention, and is the sectional view of the electric blower of FIG. 1A in line AA. It is a figure which shows the diffuser part of the blower in 1st Embodiment of an invention. It is a comparative figure of the electric blower efficiency in the experiment which combined the blower in the embodiment of this invention individually with an electric motor. It is a figure which compared the electric blower efficiency by the number of blowers and diffuser blades in the embodiment of this invention, and the noise of a blade passing frequency primary component. It is a perspective view of the electric vacuum cleaner to which the electric blower in embodiment of this invention is applied. It is sectional drawing of the vacuum cleaner main body in the electric vacuum cleaner of FIG.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The vacuum cleaner 400 will be described as an embodiment of the present invention with reference to FIGS. 7 and 8.

In the following, the case where it is applied to a rechargeable vacuum cleaner 400 that can be used by appropriately switching between the stick type and the handy type will be described as an example, but various types such as stick type only and handy type only will be described. It can be applied to vacuum cleaners.

FIG. 7 shows an electric vacuum cleaner equipped with an electric blower in this embodiment, (a) is a perspective view when used as a stick type, and (b) is a side view when using the electric vacuum cleaner as a handy type. is there.

As shown in FIG. 7A, the vacuum cleaner 400 is a vacuum cleaner that houses a dust collecting chamber 401 that collects dust and an electric blower 200 (FIG. 1) that generates a suction airflow required for collecting dust. Switch unit for turning on / off the main body 409, the telescopic pipe 402 provided to be expandable and contractible with respect to the vacuum cleaner main body 409, the stick grip 403 provided at one end of the telescopic pipe 402, and the electric blower 200 provided on the stick grip 403. It is configured with 404.

The vacuum cleaner 400 shown in FIG. 7A is in a stick state, in which the telescopic pipe 402 is extended and the stick grip 403 is fixed to the opposite side of the vacuum cleaner main body 409 via the telescopic pipe 402. .. A mouthpiece 405 is attached to the other end of the vacuum cleaner body 409, and the vacuum cleaner body 409 and the mouthpiece 405 are connected by a connecting portion 406.

The vacuum cleaner 400 shown in FIG. 7B is in a handy state, in a state where the telescopic pipe 402 is housed in the vacuum cleaner main body 409 and the stick grip 403 is close to the vacuum cleaner main body 409 via the telescopic pipe 402. is there. In this state, by using the handy grip 407 arranged on the vacuum cleaner main body 409 instead of the stick grip 403, cleaning in the handy state is facilitated. A mouthpiece (gap nozzle) 408 is attached to the other end of the vacuum cleaner body 409, and the vacuum cleaner body 409 and the mouthpiece 408 are connected by a connecting portion 406. In the above vacuum cleaner 400, by operating the switch portion 404 of the stick grip 403, the electric blower 200 (see FIG. 1) housed in the vacuum cleaner main body 409 is driven to generate a suction airflow. Then, dust is sucked from the mouthpieces 405 and 408, and is collected in the dust collecting chamber 401 of the vacuum cleaner main body 409 through the connecting portion 406.

FIG. 8 is a vertical cross-sectional view of the vacuum cleaner main body equipped with the electric blower in this embodiment. Note that FIG. 8 shows a handy state in which the mouthpiece 408 is removed from the vacuum cleaner main body 409. As shown in FIG. 8, inside the vacuum cleaner main body 409, an electric blower 200 for generating suction force, a battery unit 410 for supplying electric power to the electric blower 200, and a drive circuit 411 are provided. The air sucked from the mouthpieces 405 and 408 (see FIGS. 6A and 6B) passes through the flow path provided in the vacuum cleaner main body 409 and is arranged in the dust collecting chamber 401 in front of the electric blower 200. Is sent to and collected in the dust collecting chamber 401. Then, the air after the dust is separated in the dust collecting chamber 401 passes through the electric blower 200 and the drive circuit 411, and is discharged to the outside from an exhaust port (not shown) formed in the vacuum cleaner main body 409.

Next, the electric blower 200 will be described with reference to the external view of the electric blower shown in FIG. 1A and the vertical sectional view of the electric blower shown in FIG. 1B. The electric blower 200 is roughly classified into a blower unit 201 and an electric motor unit 202. In the blower unit 201, a partition plate 2 is arranged on the centrifugal impeller 1 which is a rotary blade and the electric motor unit 202 side which is the back surface of the centrifugal impeller 1, and the centrifugal impeller 1 and the outer peripheral portion of the centrifugal impeller 1 are arranged. The diffuser blade 23 is arranged in the fan casing 3 made of resin for accommodating the diffuser blade. The partition plate 2 is formed with an annular flow path 25 that allows air to flow into the electric motor portion 202 at the inner surface of the fan casing 3 and the outer peripheral end 2a of the partition plate 2. An air suction port 4 is provided on the upper surface of the fan casing 3. The centrifugal impeller 1 is made of thermoplastic resin and is directly connected to the rotating shaft 5. Here, in this embodiment, the centrifugal impeller 1 which is a rotary blade is press-fitted and fixed to the rotary shaft 5, but a screw is provided at the end of the rotary shaft 5 and the centrifugal impeller 1 is fixed by using a fixing nut. You may.

The electric motor unit 202 includes a rotor core 7 fixed to a rotating shaft 5 housed in the housing 6 and a stator core 8 fixed to the housing 6. A stator winding 9 is wound around the stator core 8 and together forms a phase winding. The phase winding is electrically connected to the drive circuit 109 provided in the electric blower 200.

The rotor core 7 is formed at an end of the rotating shaft 5 opposite to the end to which the centrifugal impeller 1 is fixed, and is made of a rare earth-based bond magnet. Rare earth-based bond magnets are made by mixing rare earth-based magnetic powder and an organic binder. As the rare earth-based bond magnet, for example, a samarium iron-nitrogen magnet, a neodymium magnet, or the like can be used. The rotor core 7 is integrally molded with the rotating shaft 5.

Although a permanent magnet is used for the rotor core 7 in this embodiment, a reluctance motor or the like, which is a kind of non-commutator motor, may be used without being bound by the permanent magnet.

Bearings 10 and 11 are provided between the centrifugal impeller 1 and the rotor core 7, and the rotating shaft 5 is rotatably supported. A spring 12 is arranged between the bearing 10 and the bearing 11 in a compressed state to apply a preload to the bearing 10 and the bearing 11. The bearings 10 and 11 and the spring 12 are included in the bearing cover 13. The housing 6 is made of synthetic resin and has a support portion 14 for fixing the bearing cover 13. A plurality of cooling fins 13a long in the rotation axis direction, which are heat sinks for cooling the bearings 10 and 11, are provided on the outer periphery of the bearing cover 13. The bearing cover 13 is made of a non-magnetic metal material and is integrated with the resin housing 6 by insert molding.

A screw hole 15 extending in the rotation axis direction is formed at the end of the support portion 14 of the resin housing 6. A fixing screw 16 can be screwed into the screw hole 15, and the partition plate 2 is fixedly installed in the resin housing 6 by screwing the fixing screw 16.

An annular flow path 25 is formed between the inner surface 3a of the fan casing 3 and the outer peripheral end 2a of the partition plate 2. A plurality of diffuser blades 23 are installed on the partition plate 2 in the circumferential direction around the rotation shaft 5. The area of the annular flow path formed between the inner surface 3a of the fan casing 3 and the outer peripheral end 2a of the partition plate 2 is set to be larger than the outlet area of the centrifugal impeller 1. As a result, the increase in the flow velocity in the annular flow path portion and the increase in the loss in the annular flow path portion are suppressed. Further, the diffuser blade 23 of the partition plate 2 substantially matches the flow flowing out from the centrifugal impeller 1 and the blade inlet angle at the design point, and the diffuser blade 23 reduces the velocity component in the rotation direction of the flow. , The diffuser effect is enhanced and the blower efficiency is improved.

Further, by installing the partition plate 2 on the electric motor unit 202 side which is the back surface of the centrifugal impeller 1, the flow path loss of the electric motor unit 202 is suppressed by suppressing the turbulence of the air flow in the electric motor unit 202 due to the centrifugal impeller 1. It is possible to suppress the increase in the disk friction loss of the centrifugal impeller 1 and reduce the disc friction loss.

The housing 6 is provided with an opening 17 so that air can flow into the housing 6, and an exhaust port 18 for discharging air to the outside of the electric blower 200. The stator core 8 arranged at the end of the housing 6 is fixed to the housing 6 by a fixing screw 19.

Next, the flow of air in the electric blower 200 will be described. When the centrifugal impeller 1 which is a rotary blade is rotated by driving the electric motor unit 202, air flows in from the air suction port 4 of the fan casing 3 and flows into the centrifugal impeller 1. The inflowing air is boosted and accelerated in the centrifugal impeller 1 and discharged from the outer periphery of the centrifugal impeller 1. When the air flow flowing out from the centrifugal impeller 1 passes through the diffuser blade 23, it flows along the blade and the velocity component in the rotational direction of the flow is reduced. The flow leaving the diffuser blade 23 flows into the electric motor portion 202 from the annular flow path 25 formed by the inner surface of the fan casing 3 and the outer peripheral end 2a of the partition plate 2.

The air that has flowed into the electric motor unit 202 flows into the inside of the housing 6 through the opening 17 of the housing 6. The cooling fins 13a of the bearing cover 13 are cooled by the inflow air, and the bearings 10 and 11 are cooled through the bearing cover 13. Further, the rotor core 7, the stator core 8, and the stator winding 9 are cooled and discharged to the outside. As a result, each part in the housing 6 is cooled. A part of the air flow flowing into the housing 6 is discharged to the outside from the exhaust port 18 of the housing 6. The operating rotation speed of the electric motor is 80,000 to 100,000 min ^-1 .

A protrusion 20 is provided at the end of the fan casing 3, and a mounting hole 21 for fixing the fan casing 3 to the housing 6 is provided. A claw-shaped protrusion 22 is provided at the end of the housing 6 on the blower portion 201 side, and is fitted and connected to the mounting hole 21 of the fan casing 3.

Next, the blower unit 201 of this embodiment will be described with reference to FIGS. 2 to 3. FIG. 2A is a perspective view of the centrifugal impeller according to the embodiment of the present invention, FIG. 2B is a cross-sectional view of the centrifugal impeller, FIG. 3 is a blower portion according to the embodiment of the present invention, and FIG. It is sectional drawing of the electric blower of a) in line AA.

First, the centrifugal impeller 1 which is a rotary blade in one embodiment according to the present invention will be described with reference to FIG. The centrifugal impeller 1 of the embodiment according to the present invention is composed of a shroud plate 33, a hub plate 26, and a plurality of blades 27. The hub plate 26 and the blade 27 are integrally molded with a thermoplastic resin. The shroud plate 33 made of a thermoplastic resin has an annular suction opening 28 formed in the center thereof to suck air.

A concave groove 29 is formed at a position corresponding to the blade 27 on the flow path surface of the shroud plate 33, and extends to the outer diameter side. The concave groove 29 is provided with a through hole 30. At the center of the hub plate 26, a convex boss 31 into which the rotating shaft 5 is inserted and fixed is formed. The blades 27 integrally molded with the hub plate 26 are installed at equal intervals in the circumferential direction, and have a blade shape that recedes in the rotational direction from the inner diameter side to the outer diameter direction. The boss 31 has a boss curved surface 31a formed so as to go from the axial direction to the radial direction. A protruding claw 32 and a rib for welding are formed on the upper surface of the blade 27. Centrifugal impeller 1 by engaging the protruding claw 32 of the blade 27 with the through hole 30 of the shroud plate 33, and the concave groove 29 of the shroud plate 33 with the blade 27, and joining the claw 32 and the welding rib by welding. Is formed. The number of blades in the figure is eight, but other blades may be used.

Since the welded rib melts in the concave groove 29, the volume of the welded rib is made smaller than the volume of the gap when the blade 27 is inserted into the concave groove 29. That is, it is possible to prevent the molten resin material from protruding into the flow path of the centrifugal impeller 1. Further, since the welding ribs of the blades 27 are melted and welded to the shroud plate 33, leakage flow between the blades 27 can be prevented. In this embodiment, the shroud plate 33 is provided with a through hole 30 in order to determine the positions of the shroud plate 33 and the blade 27, but the shroud plate 33 may be provided with a through hole 30 without being caught by the shroud plate 33, and may have a concave shape that does not penetrate. Any shape may be used as long as it can be fitted to 32 and the shroud plate 33 and the blade 27 can be positioned. Further, a convex portion 26a is provided on the outer periphery of the blade 27 of the hub plate 26 on the back surface side, and the balance can be corrected by rotating the centrifugal impeller 1 and scraping the convex portion 26a. As a result, the amount of imbalance of the centrifugal impeller 1 can be reduced, and vibration and noise can be reduced. Although FIG. 2 shows a closed type centrifugal impeller provided with the shroud plate 33, the boss curved surface 31a is applied to the outer peripheral portion of the impeller in the axial direction regardless of the presence or absence of the open type centrifugal impeller without the shroud plate 33 or the shroud plate. It may be a diagonal flow impeller inclined to.

Next, the blower 201 of the embodiment according to the present invention will be described with reference to FIGS. 1 and 3. In the blower 201 according to the embodiment of the present invention, 15 diffuser blades 23 arranged at equal intervals in the circumferential direction are installed on the outer peripheral portion of the centrifugal impeller 1 which is a rotary blade. The shape of the diffuser blade 23 in the axial direction is formed from the partition plate 2 toward the fan casing, and is integrally molded with the partition plate 2 (FIG. 4). The inlet height b _{3 of the} diffuser (the axial dimension of the hub plate and the fan casing 3b on the fan casing side of the partition plate 2 and the leading edge of the diffuser blade) is the flow path height (outlet height b ₂ ) at the outermost diameter of the impeller. The ratio b ₃ / b ₂ to and b ₃ / b ₂ is set to 1.16 so that the axial positions of the diffuser partition plate and the impeller hub plate are substantially the same. As a result, the deceleration of the flow at the inlet of the diffuser is increased to improve efficiency, and the performance variation due to the position of the impeller in the axial direction, which tends to occur during mass production, is reduced. Further, the diffuser inlet diameter D ₃ has a ratio D ₃ / D ₂ with the outermost diameter D ₂ of the impeller set to 1.1 to achieve both high efficiency and low noise.

Here, the diffuser blade shape will be described. The diffuser blade 23 has an eclipse angle of about 80 degrees between the chord length, the front edge of the diffuser, and the line connecting the center of rotation. This is larger than the blade outlet angle β ₂ , which is the angle formed by the straight line connecting the trailing edge of the impeller blade and the center of the rotation axis shown in FIG. 3 and the tangent line on the pressure surface of the outer edge of the blade. We are trying to improve efficiency by decelerating in the diffuser. If the outer edge of the blade is provided with a taper or R part, the blade outlet angle at the outermost edge of the outermost diameter excluding these parts may be β ₂ .

Further, the diffuser blade 23 has a blade shape in which the solidity divided by the blade chord length C (the length connecting the front edge 23a to the trailing edge 23b of the diffuser blade 23) and the blade mounting interval is about 1. The solidity may be about 1 to 1.3. If the solidity is 1 or more, the throat portion 24 is formed by the adjacent blade, and the throat portion 24 is formed on the trailing edge 23b side from the center of the chord length of the adjacent blade. It has features and can be highly efficient.

In addition, the maximum thickness ratio t / C, which is obtained by dividing the maximum thickness t of the diffuser blade by the chord length C of the diffuser blade, is set to about 8%, achieving both a thickness that is easy to mold during mass production and high efficiency by reducing the drag coefficient. ing. The maximum thickness ratio is preferably 6 to 12%. As a result, it is possible to prevent damage to the blades due to repeated stress even when operating in an unstable phenomenon such as turning stall, which tends to occur under operating conditions on the side with a lower air volume than the design point air volume. In addition, since it has a wing shape with a solidity of about 1, if the wing chord length is 9 mm or more and the maximum thickness ratio is 8%, the maximum wing thickness can be secured at 0.7 mm or more, and sink marks during molding can be secured. It is possible to prevent it and reduce performance variations during mass production. The minimum thickness of the diffuser blade 23 is set to 4% or more of the chord length to prevent the resin from chipping during molding.

The diffuser blade 23 described with reference to FIG. 4 is formed integrally with the partition plate 2 and is in contact with the fan casing 3 on the opposite side of the partition plate 2. By contacting the contact surface 3b between the fan casing 3 and the diffuser blade 23 with a sealing material or a different soft material (for example, synthetic rubber), it is possible to suppress the leakage flow between the diffuser blades and improve efficiency. Is possible. Further, as shown in FIG. 1, the flow path of the diffuser blade formed by the fan casing 3 and the partition plate 2 is not horizontal but is inclined in the axial direction. As a result, the loss when the flow emitted from the diffuser blade 23 collides with the inner wall 3a of the fan casing is reduced, and high efficiency is achieved.

Here, FIG. 5 shows the effect of the efficiency of the electric blower due to the solidity of the diffuser blade. The test results are the same for the impeller and diffuser inlet angles. That is, the difference between the diffuser having a solidity close to that of the prior art and the blower of the present embodiment provided with the diffuser blade 23 is shown. In FIG. 5, the horizontal axis shows the solidity, and the vertical axis shows the experimental result of the electric blower efficiency. Here, the definition of the electric blower efficiency in FIG. 5 is the product of the suction volume flow rate, the compressibility coefficient, and the blower pressure divided by the input of the electric blower. From FIG. 5, it can be seen that the blower efficiency is high with a solidity of about 1 to 1.3, and the blower efficiency is lowered with a diffuser of 0.9 or less as in the prior art. This is because the chord length is short, so that the deceleration by the blade, that is, the rotational velocity component of the flow flowing out from the impeller cannot be reduced. If the solidity is too large, the friction loss of the blades will increase and the blower efficiency will decrease.

Next, FIG. 6 shows the effects of the electric blower efficiency of the diffuser and the blade passing frequency noise in which the solidity of the diffuser blades is fixed and the number of diffuser blades is changed. This test result is a test result in which the impeller, diffuser inlet angle, and solidity are set to about 1. The operating rotation speed is about 84,000 min ^-1 , and the primary component of the blade passing frequency noise is about 11 kHz. In FIG. 6, the horizontal axis shows the number of diffuser blades, and the vertical axis shows the experimental results of the primary components of the electric blower efficiency and the blade passing frequency noise. From FIG. 6, it can be seen that when the number of diffuser blades is 15, the noise is the lowest and the blower efficiency is high. When the number of diffuser blades is 15 or 17, the amount of protrusion (excellent amount) from the frequency band centered on the turbulent noise, which is a frequency close to the primary component of the blade passing frequency noise, is 6 dB or less. This leads to improved sound quality. That is, in order to achieve both high efficiency and low noise, it is desirable that the solidity is about 1 to 1.3 and the number of diffuser blades is 15 to 17.

According to the electric blower 200 of the present embodiment described above, the solidity is about 1 to 1.3, and the number of diffuser blades has 15 to 17 diffusers, so that the flow flows out from the diffuser blades 23. By reducing the speed component in the direction of rotation, an efficient diffuser effect can be obtained, the predominant amount of wing passing frequency noise is as small as 6 dB or less, low noise and good sound quality, and sink marks during molding can be suppressed for mass production. It is possible to obtain an electric blower that can reduce the variation in performance. Further, by using the above-mentioned electric blower, it is possible to provide a small vacuum cleaner having an improved suction force, a small operating noise, and a good sound quality in a wide air volume range.

The present invention is not limited to the above-described examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and is not necessarily limited to those having all the described configurations. It is possible to add / delete / replace other configurations with respect to a part of the configurations of the examples.

1 Centrifugal impeller 2 Partition plate 2a Outer end of partition plate 3 Fan casing 3a Inner surface of fan casing 3b Surface on which diffuser blades are installed on the inner surface of fan casing 4 Air suction port 5 Rotating shaft 5a Rotating shaft center 6 Housing 7 Rotor core 8 stator core 9 Stator winding 10 Bearing 11 Bearing 12 Spring 13 Bearing cover 13a Cooling fin 14 Support 15 Screw hole 16 Screw 17 Opening 18 Exhaust port 19 Stator core fixing screw 20 Protrusion 21 Mounting hole 22 Claw protrusion 23 Diffuser wing 23a In front of diffuser wing Edge 23b Diffuser blade trailing edge 24 Throat part 25 Circular flow path 26 Hub plate 26a Convex part 27 Blade 28 Suction opening 29 Concave groove 30 Through hole 31 Boss 31a Boss curved surface 32 Claw 33 Shroud plate 200 Electric blower 201 Electric blower part 202 400 Vacuum cleaner body 401 Dust collection room 402 Telescopic pipe 403 Stick grip 404 Switch part 405 Mouthpiece 406 Connection part 407 Handy grip 408 Mouthpiece (gap nozzle)
409 Vacuum cleaner body 410 Battery unit 411 Drive circuit

Claims (5)

An electric motor having a rotor and a stator, a housing having one end open to accommodate the electric motor, a rotating shaft provided on the rotor, a rotating blade fixed to the rotating shaft, and the rotary blade. A partition plate arranged on the electric motor side, a plurality of diffuser blades provided on the opening side of the housing, and a fan casing covering the diffuser blades are provided on the outer peripheral portion of the rotary blades, and the diffuser blades are provided by adjacent blades. A throat portion is formed, the throat portion is formed on the trailing edge side from the center of the chord length of the adjacent wing, and the line connecting the front edge of the diffuser wing and the center of rotation does not touch the adjacent diffuser wing. The number of diffuser blades is 15 to 17, and the area of the annular flow path formed between the inner surface of the fan casing and the circular outer peripheral end of the partition plate is larger than the outlet area of the centrifugal impeller. An electric blower and an electric motor including the electric blower, wherein the end portion of the fan casing on the electric motor portion side is fitted and connected to the end portion of the housing on the blower portion side. Vacuum cleaner. An electric motor having a rotor and a stator, a housing having one end open to accommodate the electric motor, a rotating shaft provided on the rotor, a rotating blade fixed to the rotating shaft, and the rotary blade. A partition plate arranged on the electric motor side, a plurality of diffuser blades provided on the opening side of the housing, and a fan casing covering the diffuser blades are provided on the outer peripheral portion of the rotary blade, and the solidity of the diffuser blade is about. The line connecting the front edge of the diffuser blade and the center of rotation is 15 to 17 diffuser blades without contacting the adjacent diffuser blade, and the inner surface of the fan casing and the circular shape of the partition plate. The area of the annular flow path formed between the fan casing and the outer peripheral end of the fan casing is set to be larger than the outlet area of the centrifugal impeller, and the end of the fan casing on the motor portion side is the blower of the housing. An electric blower and an electric vacuum cleaner equipped with the electric blower, which are fitted and connected to an end portion on a portion side. The electric blower according to claim 1 or 2, wherein the maximum thickness ratio of the diffuser blade is formed at 6 to 12% of the chord length, and a vacuum cleaner provided with the electric blower. The electric blower according to claim 1 or 2, wherein the inlet height of the diffuser blade is larger than the impeller outlet height, and a vacuum cleaner provided with the electric blower. The electric blower according to any one of claims 1 to 4, wherein the diffuser blade is installed in a flow path inclined in the axial direction, and a vacuum cleaner provided with the electric blower.

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