JP2019002305A - Electric blower and vacuum cleaner including the same - Google Patents

Abstract

The present invention provides an electric blower that is small, lightweight, and highly efficient in a wide air volume range, and also provides an electric vacuum cleaner having an improved suction power in a wide air volume range. An electric motor having a rotor and a stator, a housing having an open end and accommodating the electric motor, a rotating shaft provided on the rotor, a rotating wing fixed to the rotating shaft, A partition plate arranged on the electric motor side of the rotor, a diffuser blade provided on the opening side of the housing, and having a plurality of rows of diffuser blades in an outer peripheral portion of the rotor in a radial direction, and a fan casing covering the diffuser blade. The chord length of the diffuser vane on the rotating vane side is substantially equal to or greater than the chord length of a subsequent stage. [Selection diagram] FIG.

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. 3356510 (Patent Document 1).

In this patent document 1, “in a diffuser with blades of a centrifugal or mixed flow pump having a configuration in which the blades are arranged in the fluid flow field on the outer periphery of the impeller of the centrifugal or mixed flow pump, the blades of the diffuser are arranged in the circumferential direction. The first and second rows are arranged in the same number and in the radial direction, and are arranged so that the strings of the first row blades and the second row blades are parallel to each other ± 7.5 °. Set up
Centrifugal or mixed flow type characterized in that the trailing edge of the first row of blades and the leading edge of the second row of blades are spaced apart in the radial direction by a distance ΔR = 0.05L to 0.4L. Diffuser with pump blades. Where L is the chord length of the first row of blades. Is described.

Japanese Patent No. 3356510

Since the electric airflow greatly changes depending on the operating conditions such as clogging of the filter and the material of the floor to be cleaned, an electric blower having a strong suction force in a wide airflow range is required.
The air that flows in from the suction port of the electric blower is boosted and accelerated by the impeller and decelerated by the diffuser blades, so that the kinetic energy of the air that flows into the diffuser is converted into pressure energy and the static pressure increases. .
The vaned diffuser can perform an excellent pressure recovery at the design point air volume, but at the non-design point air volume, the diffuser performance deteriorates due to a mismatch between the inlet angle of the diffuser blade and the inflow angle of the air flow into the diffuser. Therefore, although the suction force of the vacuum cleaner is high at the design point air volume, there is a problem that the suction force 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 running type has a small power consumption and a small maximum air volume. For this reason, when the filter is clogged, there is a problem in that the dust conveying ability is reduced and the suction force of the vacuum cleaner is reduced. Furthermore, a vacuum cleaner driven by a cordless stick type or a battery (secondary battery) is required to be small and lightweight, and the electric blower mounted on the vacuum cleaner has a strong suction force in a wide air flow range, and is small in size. There must be a balance between things.
Patent Document 1 relates to a vaned diffuser such as a centrifugal or mixed flow type liquid pump, a gas blower, a compressor or the like (collectively referred to as “pump” in the present specification). In Patent Document 1, a centrifugal compressor equipped with a vaned diffuser is described. Centrifugal compressors have two rows of diffuser blades arranged radially in the outer periphery of the impeller to efficiently convert the kinetic energy of the fluid flowing out from the impeller into static pressure, and the outer diameter of the diffuser blade At a larger position, a vaneless diffuser and a return flow path that redirects radial flow to axial flow are installed. In addition, it is shown by the centrifugal compressor of patent document 1 that the diffuser blade close | similar to a centrifugal impeller is smaller than another diffuser blade. The centrifugal compressor of Patent Document 1 has a vaneless diffuser formed on the outer periphery of the diffuser blade, and a return channel (a channel bent in the axial direction by the casing) on the outer periphery. When the technique of Patent Document 1 is applied to an electric blower to be used, the blower becomes large, resulting in a problem that the product becomes large. Moreover, when the return flow path which consists of a diffuser and a casing is made to adjoin, fan efficiency may fall.

  An object of the present invention is to solve the above-described problem, and even when a return flow path composed of a diffuser blade and a casing is adjacent, while providing a small and lightweight electric blower that is highly efficient in a wide air volume range, An object of the present invention is to provide a small vacuum cleaner with improved suction power in a wide air volume range.

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

  The present invention includes a number of means for solving the above problems. For example, an electric motor having a rotor and a stator, a housing having one end opened and housing the electric motor, and the rotor are provided. A rotating shaft, a rotating blade fixed to the rotating shaft, a partition plate arranged on the motor side of the rotating blade, a diffuser in which a plurality of diffuser blades are radially formed on the outer peripheral side of the rotating blade, and an outer periphery of the diffuser The fan chord length of the diffuser blade close to the outer diameter of the rotary blade is approximately the same as or greater than the chord length of the diffuser blade installed on the other outer peripheral portion. The

  According to the present invention, even when a return flow path composed of a diffuser blade and a casing is adjacent to each other, a small and light electric blower that is highly efficient in a wide air flow area and has a suction capacity improved in a wide air flow area. Can provide a vacuum cleaner.

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

External view of the electric blower in the first embodiment of the present invention It is a longitudinal cross-sectional view of an electric blower. (A) is a perspective view of the centrifugal impeller in the 1st Embodiment of this invention, (b) is a longitudinal cross-sectional view of a centrifugal impeller. It is a figure which shows the air blower part in the 1st Embodiment of invention, and is sectional drawing in the AA of the electric blower of Fig.1 (a). It is a figure which shows the diffuser part of the air blower in the 1st Embodiment of invention. It is a figure which shows the fan casing of the air blower in the 1st Embodiment of invention. It is a comparison figure of the electric blower efficiency which experimented combining the air blower in embodiment of this invention, and the air blower of only the diffuser blade | wing 23 individually with the electric motor. It is a figure which shows the fan casing part of the air blower in the 2nd Embodiment of invention. It is a figure which shows the diffuser part of the air blower in the 3rd Embodiment of invention. It is the comparison figure which computed the fan efficiency of the air blower in embodiment of this invention, and the air blower of a prior art using the flow analysis. It is a perspective view of the vacuum cleaner to which the electric blower in the embodiment of the present invention is applied. It is sectional drawing of the vacuum cleaner main body in the vacuum cleaner of FIG.

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

  A vacuum cleaner 300 according to an embodiment of the present invention will be described with reference to FIGS. 10 and 11. FIG. 10 shows a perspective view of a vacuum cleaner to which the electric blower of this embodiment is applied. As shown in FIG. 10, reference numeral 100 denotes a dust collecting chamber 101 that collects dust and an electric blower 200 (FIG. 1) that generates a suction airflow necessary for collecting dust, and 102 denotes a cleaner main body. A holding part to which 100 is attached, 103 is a grip part provided at one end of the holding part 102, and 104 is a switch part for turning on and off the electric blower 200 provided in the grip part. A suction body 105 is attached to the other end of the holding part 102, and the cleaner body 100 and the suction body 105 are connected by a connection part 106. Reference numeral 107 denotes a charging stand for charging the battery unit 108.

  In the above configuration, when the switch unit 104 of the grip unit 103 is operated, the electric blower 200 housed in the cleaner body 100 is operated to generate a suction airflow. Then, dust is sucked from the suction body 105 and collected in the dust collecting chamber 101 of the cleaner body 100 through the connecting portion 106.

Next, the cleaner body 100 will be described using a cross-sectional view schematically showing the cleaner body 100 in the electric vacuum cleaner shown in FIG. An electric blower 200 that generates suction force, a battery unit 108 that drives the electric blower 200, a drive circuit 109, and a dust collection chamber 101 are disposed inside the cleaner body 100.
The vacuum cleaner main body 100 can be removed from the holding portion 102 and used as a handy vacuum cleaner. The vacuum cleaner main body 100 is provided with a main body grip portion 110 and a mouth opening 111. Reference numeral 112 (FIG. 10) denotes a main body switch unit for turning on and off the electric blower 200 when used as a handy cleaner. The main body switch 112 can be operated even when the cleaner main body 100 is attached to the holding unit 102. 10 and 11 show a cordless vacuum cleaner in which the suction opening 111 and the connecting portion 106 can be removed, but a vacuum cleaner with a power cord not equipped with a battery may be used.

  Next, the electric blower 200 will be described with reference to an external view of the electric blower shown in FIG. 1A and a longitudinal sectional view of the electric blower shown in FIG. The electric blower 200 is roughly divided into a blower unit 201 and an electric motor unit 202. The blower unit 201 includes a centrifugal impeller 1 that is a rotary blade, and a partition plate 2 disposed on the electric motor unit 202 side that is the back surface of the centrifugal impeller 1, and the outer peripheral portion of the centrifugal impeller 1 and the centrifugal impeller 1. In the radial direction, two rows of diffuser blades 23 and 24 are arranged, and the resin fan casing 3 accommodates the diffuser blades. In the partition plate 2, an annular flow path 25 through which air flows into the electric motor unit 202 is formed by the inner surface of the fan casing 3 and the outer peripheral end 2 a 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 a 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 using a fixing nut. May be.

  The electric motor unit 202 includes a rotor core 7 fixed to the rotary 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 a driving circuit 109 provided in the electric blower 200.

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

  In this embodiment, a permanent magnet is used for the rotor core 7. However, a reluctance motor that is a kind of a non-commutator motor may be used without being bound by this.

  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 disposed between the bearing 10 and the bearing 11 in a compressed state, and preload is applied to the bearing 10 and the bearing 11. The bearings 10 and 11 and the spring 12 are contained in a bearing cover 13. The housing 6 is made of synthetic resin and has a support portion 14 for fixing the bearing cover 13. On the outer periphery of the bearing cover 13, a plurality of cooling fins 13 a that are long in the direction of the rotation axis, which is a heat sink for cooling the bearings 10 and 11, are provided. The bearing cover 13 is made of a nonmagnetic 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 on the resin housing 6 by screwing the fixing screw 16.
An annular channel 25 is formed between the inner surface 3 a of the fan casing 3 and the outer peripheral end 2 a of the partition plate 2. In the partition plate 2, a plurality of diffuser blades 23 are installed in the circumferential direction around the rotation shaft 5. In addition, a plurality of subsequent diffuser blades 24 are installed on the outer peripheral portion of the diffuser blade 23 in the circumferential direction around the rotation shaft 5. The rear edge 24b of the diffuser blade 24 protrudes from the outer peripheral end 2a of the partition plate 2 into the annular flow path.
The area of the annular flow path formed between the inner surface 3 a of the fan casing 3 and the outer peripheral end 2 a of the partition plate 2 is set to be larger than the exit area of the centrifugal impeller 1. Thereby, 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. In addition, the diffuser blade 23 of the partition plate 2 has a blade inlet angle substantially coincident with the flow flowing out from the centrifugal impeller 1 at the design point, and the diffuser blade 23 reduces the rotational speed component of the flow. The diffuser effect is enhanced and the blower efficiency is improved. Further, the diffuser blade 24 installed on the outer periphery of the diffuser blade 23 can further suppress the pressure loss generated in the annular flow path and the electric motor by further reducing the rotational speed component of the flow flowing out from the diffuser blade 23. Thus, the fan efficiency can be further improved.
Moreover, the flow path loss of the electric motor part 202 is suppressed by installing the partition plate 2 on the electric motor part 202 side which is the back surface of the centrifugal impeller 1, thereby suppressing the disturbance of the air flow in the electric motor part 202 by the centrifugal impeller 1. And the disc friction loss of the centrifugal impeller 1 can be reduced.

  The housing 6 is provided with an opening 17 so that air flows into the housing 6 and an exhaust port 18 for discharging the air to the outside of the electric blower 200. The stator core 8 disposed 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 motor unit 202 is driven to rotate the centrifugal impeller 1 that is a rotor blade, air flows from the air suction port 4 of the fan casing 3 and flows into the centrifugal impeller 1. The air that has flowed in is boosted and accelerated in the centrifugal impeller 1 and flows out from the outer periphery of the centrifugal impeller 1. The air flow flowing out from the centrifugal impeller 1 flows along the wing when passing through the diffuser blade 23 and the diffuser blade 24, and the rotational speed component of the flow is reduced. The flow exiting the diffuser blade 24 flows into the electric motor unit 202 from the annular flow path 25 formed by the inner surface of the fan casing 3 and the outer peripheral end 2 a of the partition plate 2.

The air that has flowed into the electric motor unit 202 flows into the housing 6 from the opening 17 of the housing 6. The cooling fins 13 a of the bearing cover 13 are cooled by the inflow air, and the bearings 10 and 11 are cooled via 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. Thereby, 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.
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-like protrusion 22 is provided at the end of the housing 6 on the blower unit 201 side, and is fitted and connected to the mounting hole 21 of the fan casing 3.

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

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

  On the flow path surface of the shroud plate 33, a concave groove 29 is formed at a position corresponding to the blade 27 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 is formed on which the rotary shaft 5 is inserted and fixed. The blades 27 integrally formed with the hub plate 26 are installed at equal intervals in the circumferential direction, and have a blade shape that retreats in the rotation direction from the inner diameter side toward the outer diameter direction. A boss curved surface 31a is formed so that the boss 31 is directed from the axial direction to the radial direction. Protruding claws 32 and welding ribs are formed on the upper surface of the blade 27. The centrifugal impeller 1 is obtained by engaging the projection 27 of the blade 27 with the through hole 30 of the shroud plate 33 and the concave groove 29 of the shroud plate 33 and the blade 27 and joining the claw 32 and the welding rib by welding. Is formed.

  Since the welding rib melts in the concave groove 29, the volume of the welding rib is made smaller than the volume of the gap when the blades 27 are inserted into the concave groove 29. That is, it can suppress that the molten resin material protrudes into the flow path of the centrifugal impeller 1. In addition, since the welding ribs of the blades 27 are melted and welded to the shroud plate 33, the leakage flow between the blades 27 can be prevented. In the present embodiment, the through hole 30 is provided in the shroud plate 33 in order to determine the positions of the shroud plate 33 and the blades 27. As long as the shroud plate 33 and the blades 27 can be positioned by being fitted with the pin 32, any shape may be used. Moreover, the convex part 26a is provided in the outer periphery of the back surface side of the blade | wing 27 of the hub board 26, and balance correction can be performed by rotating the centrifugal impeller 1 and shaving the convex part 26a. Thereby, the amount of unbalance of the centrifugal impeller 1 can be reduced, and vibration and noise can be reduced. FIG. 2 shows a closed type centrifugal impeller provided with a shroud plate 33. However, an open type centrifugal impeller without a shroud plate 33 or a boss curved surface 31a is applied to the outer periphery of the impeller regardless of the presence or absence of the shroud plate. It may be a mixed-flow impeller inclined in the direction.

Next, an air blower 201 according to an embodiment of the present invention will be described with reference to FIGS. In the blower 201 in one embodiment according to 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 formed with the partition plate 2 (FIG. 4). On the outer periphery of the diffuser blade 23, the same number of diffuser blades 24 as the diffuser blade 23 are installed. FIG. 5 is a perspective view of the fan casing 3 as seen from the electric motor side. The shape of the diffuser blades 24 in the height direction is formed from the suction opening 28 side of the fan casing 3 toward the partition plate 2 and is formed integrally with the fan casing 3. The rear edge 24b of the diffuser blade 24 protrudes from the outer peripheral end 2a of the partition plate 2 into the annular flow path, and is integrated with the inner surface 3a of the fan casing. The trailing edge 24b of the diffuser blade 24 is integrated with the inner surface 3a of the fan casing 3, so that the rotational component in the rotational direction of the flow on the trailing edge side of the diffuser blade 24 is reduced, and the flow generated in the return flow path and the motor section. The loss of is suppressed. Note that the rear edge 24 b of the diffuser blade 24 does not have to protrude into the annular flow path 25 when an annular flow path area larger than the exit area of the centrifugal impeller can be secured.
Here, the diffuser blade shape will be described. The chord length C of the diffuser blade 23 (the length connecting the leading edge 23a to the trailing edge 23b of the diffuser blade 23) is the chord length D of the diffuser blade 24 (the length connecting the leading edge to the trailing edge of the diffuser blade 24). The diffuser vane 23 is longer than the centrifugal impeller, and the flow direction is increased. The circumferential positions of the diffuser blade 23 and the subsequent diffuser blade 24 are a line connecting the rear edge 23b of the diffuser blade 23 and the rotation axis center 5a, and a line connecting the front edge 24a of the diffuser blade 24 and the rotation axis center 5a. And the leading edge 24a of the diffuser blade 24 at the rear stage is the trailing edge of the diffuser blade 23. It is installed so as to be located in the counter-rotating direction compared to 23b.
Further, the maximum thickness ratio obtained by dividing the maximum thickness t of the diffuser blade by the diffuser blade chord length C is 10 to 25%, and the diffuser blade 23 and the diffuser blade 24 have the same value. That is, the maximum blade thickness of the diffuser blade 23 close to the centrifugal impeller is thicker than that of the diffuser blade 24 at the subsequent stage. This makes it possible to prevent damage to the blade due to repeated stress even when operating in an unstable phenomenon such as turning stall, which is likely to occur under operating conditions on the low air volume side compared to the design point air volume.
The diffuser blade 23 described with reference to FIGS. 4 to 5 is formed integrally with the partition plate 2 and the diffuser blade 24 with the fan casing, and the diffuser blade 23 close to the centrifugal impeller and the diffuser blade 23 at the rear stage are formed at different parts. ing. In addition, the contact surface 3b between the fan casing 3 and the diffuser blade 23 is brought into contact with a sealing material or a different soft material (for example, synthetic rubber), so that the leakage flow between the diffuser blades can be suppressed and the efficiency can be improved. Is possible. In addition, even on the surface where the partition plate 2 and the diffuser blade 24 are in contact with each other, the leakage flow between the diffuser blades can be suppressed by using a sealing material or a different soft material to make contact, and high efficiency can be achieved. .
The number of diffuser blades 23 and 24, the number of projections 20 at the end of the fan casing 3, and the number of mounting holes 21 for fixing the fan casing 3 to the housing 6 are configured by mutual greatest common divisors. The circumferential positions of 23 and 24 are set to predetermined positions, and mass productivity is improved so as not to cause an error in the circumferential position during assembly.
Moreover, although the number of diffuser blades of the present embodiment is 15, it may be 13-19. When the number of diffuser blades is large, the blade length and the maximum thickness of the diffuser blade 23 close to the centrifugal impeller and the subsequent diffuser blade 24 may be substantially the same.
Here, FIG. 6 shows a comparison of the efficiency of the electric blower in which the blower of the present embodiment provided with the diffuser blade 23 and the diffuser blade 24 and the blower having only the diffuser blade 23 are individually combined with the electric motor and tested. FIG. 6 shows the dimensionless airflow with the design point airflow set to 1 on the horizontal axis, and the experimental results of the electric fan efficiency on the vertical axis. Here, the definition of the electric blower efficiency in FIG. 6 is obtained by dividing the product of the suction volume flow rate, the compressibility coefficient, and the blower pressure by the input of the electric blower. As shown in FIG. 6, the blower equipped with the diffuser blades of the embodiment has an improved efficiency at a dimensionless airflow 1 (design point airflow) compared to a fan with only the diffuser blades 23, and the fan efficiency on the larger airflow side than the dimensionless airflow. It can be seen that it can be improved. That is, it can be seen that by installing the diffuser blade 24 installed in the subsequent stage, the efficiency can be maintained high over a wide operation range.

  According to the electric blower 200 of the present embodiment described above, even when the return flow path composed of the diffuser blade and the fan casing is adjacent, the diffuser blade 24 with the chord length of the diffuser blade 23 installed on the outer periphery. The rotational speed component in the rotational direction of the flow that flows out of the diffuser blade 23 is further reduced by reducing the diffuser effect and the pressure loss that occurs in the annular flow path and the motor, thereby reducing the fan efficiency. Thus, it is possible to obtain a small and light electric blower that is highly efficient in a wide air volume range.

Next, a second embodiment will be described with reference to FIG. FIG. 7 is a perspective view of the fan casing 3 of the blower according to the second embodiment of the present invention as viewed from the electric motor side. Since the basic configuration is the same as that in the first embodiment, the same reference numerals are used for the same elements, and descriptions thereof are omitted.
In the present embodiment, the shape of the diffuser blade 24 in the height direction is formed from the suction opening 28 side of the fan casing 3 toward the partition plate 2 and is formed integrally with the fan casing 3. Further, the rear edge 24b of the diffuser blade 24 protrudes from the outer peripheral end 2a of the partition plate 2 to the annular flow path, and forms a gap of 2 mm or less with the inner surface 3a of the fan casing. If the gap between the rear edge 24b of the diffuser blade 24 and the inner surface 3a of the fan casing 3 is 2 mm or less, the rotational speed component of the flow on the rear edge side of the diffuser blade 24 can be reduced, which occurs in the return flow path and the motor section. A loss of flow is possible.
As described above, even when the return flow path composed of the diffuser blade and the fan casing is adjacent, by making the chord length of the diffuser blade 23 substantially equal to or greater than that of the diffuser blade 24 installed on the outer periphery. The rotational speed component of the flow that flows out of the diffuser blades 23 is further reduced to reduce the diffuser effect and the pressure loss that occurs inside the annular flow path and the motor, thereby contributing to the improvement of the fan efficiency and high efficiency in a wide air flow range. A small and lightweight electric blower can be obtained.

Next, a third embodiment will be described with reference to FIG. FIG. 8 is a perspective view of the diffuser portion of the blower in the third embodiment of the present invention. Since the basic configuration is the same as that in the first embodiment, the same reference numerals are used for the same elements, and descriptions thereof are omitted.
In this embodiment, the diffuser blade 23 and the diffuser blade 24 are integrally formed with the partition plate. When the diffuser blade 23 and the diffuser blade 24 are molded integrally with the partition plate 2, the shortest gap between the rear edge 23b of the diffuser blade 23 close to the centrifugal impeller 1 and the front edge 24a of the rear diffuser blade 24 is 1 mm or more. By doing so, chipping of the wing shape during resin molding and residual resin on the mold can be alleviated. The diffuser blades 23 and 24 may be molded integrally with the fan casing.
Further, when the diffuser blades 23 and 24 are integrally molded with the partition plate 2, the contact surface 3b of the fan casing 3 and the diffuser blade is brought into contact using a sealing material or a different soft material (for example, synthetic rubber), Leakage flow between the diffuser blades can be suppressed, and high efficiency can be achieved. In the case where the diffuser blade is molded integrally with the fan casing, the same effect can be obtained by using a sealing material or a different soft material on the surface where the partition plate 2 and the diffuser blade contact.
Next, FIG. 9 shows the diffuser blade described in the first to third embodiments (the chord length of the diffuser blade on the centrifugal impeller side is longer than that of the diffuser blade on the subsequent stage), and the diffuser blade of the prior art ( The comparison of the fan efficiency when the chord length of the diffuser blade on the centrifugal impeller side is shorter than that of the latter diffuser blade is shown. In addition, FIG. 9 shows the result of calculating the fan efficiency when the airflow is changed by using the dimensionless airflow with the design point airflow being 1 on the horizontal axis and the flow analysis on the vertical axis. Here, the definition of the fan efficiency in FIG. 9 is obtained by dividing the product of the suction volume flow rate, the compressibility coefficient, and the fan pressure by the impeller power.
The diffuser blade described in the embodiment from FIG. 9 can improve the efficiency with a dimensionless airflow 1 (design point airflow) and improve the blower efficiency on the low airflow side where the dimensionless airflow is 1 or less compared to the prior art. Recognize. That is, even when the return flow path composed of the diffuser blades and the fan casing is adjacent, the efficiency can be maintained high over a wide operating range, so that a small and lightweight electric blower that is highly efficient in a wide air flow range and a wide air flow rate are provided. It is possible to provide a small vacuum cleaner with improved suction power in the area.

According to the electric blower 200 of the present embodiment described above, even when the return flow path composed of the diffuser blade and the fan casing is adjacent, the diffuser blade 24 with the chord length of the diffuser blade 23 installed on the outer periphery. As compared with the above, the efficiency of the blower is improved by further reducing the rotational speed component of the flow flowing out from the diffuser blade 23 and suppressing the diffuser effect and the pressure loss generated in the annular flow path and the motor. Thus, a small and lightweight electric blower that is highly efficient in a wide air volume range can be obtained.
In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Further, a part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. In addition, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment.

DESCRIPTION OF SYMBOLS 1 Centrifugal impeller 2 Partition plate 2a Outer peripheral 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 DESCRIPTION OF SYMBOLS 9 Stator winding 10 Bearing 11 Bearing 12 Spring 13 Bearing cover 13a Cooling fin 14 Support part 15 Screw hole 16 Screw 17 Opening 18 Exhaust port 19 Stator core fixing screw 20 Projection 21 Mounting hole 22 Claw-shaped projection 23 Diffuser blade on centrifugal impeller side 23a The leading edge of the diffuser blade on the centrifugal impeller side 23b The trailing edge of the diffuser blade on the centrifugal impeller side 24 The rear diffuser blade 24a The leading edge of the following diffuser blade 24b The trailing edge of the following diffuser blade 25 Annular flow path 26 Hub plate 26a Convex part 27 Feather 8 suction opening 29 recessed groove 30 through hole 31 boss 31a boss curved 32 pawl 33 shroud plate 100 vacuum cleaner main body 200 electric blower 201 blower unit 202 motor unit

Claims (6)

  An electric motor including a rotor and a stator, a housing having one end opened to accommodate the electric motor, a rotary shaft provided in the rotor, a rotary blade fixed to the rotary shaft, and the rotary blade A partition plate disposed on an electric motor side; provided on an opening side of the housing; and a plurality of rows of diffuser blades in a radial direction on an outer peripheral portion of the rotor blade; and a fan casing that covers the diffuser blade, the rotor blade side A chord length of the diffuser blade is substantially equal to or longer than a chord length of the rear diffuser blade, and an electric blower and an electric vacuum cleaner provided with the electric blower.   An electric motor including a rotor and a stator, a housing having one end opened to accommodate the electric motor, a rotary shaft provided in the rotor, a rotary blade fixed to the rotary shaft, and the rotary blade A partition plate disposed on an electric motor side; provided on an opening side of the housing; and a plurality of rows of diffuser blades in a radial direction on an outer peripheral portion of the rotor blade; and a fan casing that covers the diffuser blade, the rotor blade side The maximum thickness of the diffuser blade is approximately equal to or greater than the maximum thickness of the latter stage, and an electric blower and a vacuum cleaner provided with the electric blower.   3. The electric blower according to claim 1, wherein the rear edge of the diffuser blade of the diffuser blade is in contact with or integral with an inner surface of the fan casing, and an electric vacuum cleaner provided with the electric blower. .   3. The electric blower according to claim 1, wherein the gap between the rear edge of the rear diffuser blade and the inner surface of the fan casing is 2 mm or less among the diffuser blades, and the electric blower is provided. Electric vacuum cleaner.   3. The electric blower according to claim 1, wherein a rear edge of a diffuser blade of a rear stage protrudes from an outer peripheral end of the partition plate among the diffuser blades, and a vacuum cleaner provided with the electric blower. .   The electric blower according to any one of claims 1 to 5, and an electric vacuum cleaner provided with the electric blower, wherein the diffuser blades are configured by different parts of the diffuser blades and the diffuser blades at the rear stage.

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