CN111441969B - Electric fan and electric dust collector with same - Google Patents
Electric fan and electric dust collector with same Download PDFInfo
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- CN111441969B CN111441969B CN201910823879.2A CN201910823879A CN111441969B CN 111441969 B CN111441969 B CN 111441969B CN 201910823879 A CN201910823879 A CN 201910823879A CN 111441969 B CN111441969 B CN 111441969B
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- Prior art keywords
- diffuser
- blade
- centrifugal
- axial
- blades
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D25/00—Pumping installations or systems
- F04D25/02—Units comprising pumps and their driving means
- F04D25/08—Units comprising pumps and their driving means the working fluid being air, e.g. for ventilation
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- A—HUMAN NECESSITIES
- A47—FURNITURE; DOMESTIC ARTICLES OR APPLIANCES; COFFEE MILLS; SPICE MILLS; SUCTION CLEANERS IN GENERAL
- A47L—DOMESTIC WASHING OR CLEANING; SUCTION CLEANERS IN GENERAL
- A47L9/00—Details or accessories of suction cleaners, e.g. mechanical means for controlling the suction or for effecting pulsating action; Storing devices specially adapted to suction cleaners or parts thereof; Carrying-vehicles specially adapted for suction cleaners
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/4206—Casings; Connections of working fluid for radial or helico-centrifugal pumps especially adapted for elastic fluid pumps
- F04D29/4226—Fan casings
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/40—Casings; Connections of working fluid
- F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
- F04D29/44—Fluid-guiding means, e.g. diffusers
- F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
- F04D29/444—Bladed diffusers
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Electric Suction Cleaners (AREA)
Abstract
The invention provides a small-sized light-weight electric fan with wide air volume range and high efficiency, and provides an electric dust collector with improved suction force in the wide air volume range. The electric blower includes: an electric motor having a rotor and a stator; a rotating shaft provided to the rotor; a rotary blade fixed to the rotary shaft; a centrifugal diffuser having a plurality of centrifugal diffuser blades formed radially on the outer peripheral side of the rotary blade; and a fan case covering the impeller, and an axial flow type diffuser having axial flow type diffuser blades forming a blade height in a radius direction is provided downstream of the centrifugal diffuser blades.
Description
Technical Field
The present invention relates to an electric blower and an electric vacuum cleaner equipped with the same.
Background
WO2016/194697 (patent document 1) discloses a conventional fan.
[ Prior art documents ]
[ patent document ]
[ patent document 1] WO2016/194697
Disclosure of Invention
[ problem to be solved by the invention ]
Since the operating air flow rate of the electric vacuum cleaner greatly varies depending on operating conditions such as clogging of the filter and the material of the floor to be cleaned, a powerful electric fan having a large suction force in a wide air flow rate range is desired. The air flowing in from the suction port of the electric fan is boosted and accelerated by the impeller and decelerated by the diffuser blades, so that the kinetic energy of the air flowing in the diffuser is converted into pressure energy, and the static pressure is increased.
The vane diffuser can perform excellent pressure recovery in terms of design point air volume, and in terms of non-design point air volume, the performance of the diffuser is reduced due to the inconsistency between the inlet angle of the diffuser vane and the inflow angle of the air flow to the diffuser. Therefore, there is a problem that the suction force of the electric vacuum cleaner is high in the design point and the air volume is reduced in the non-design point.
In a vacuum cleaner driven by a battery (2-time battery) such as a cordless stick (コードレススティック) type or an autonomous traveling type, the electric fan consumes less power and the maximum air volume is also small. Therefore, there is a problem that the dust conveying ability is lowered when the filter is clogged, and the suction force of the vacuum cleaner is lowered. Further, a vacuum cleaner driven by a cordless stick type or a battery (2-time battery) is required to be small and light, and an electric fan mounted on the vacuum cleaner is required to have 2 kinds of performances while being small in size, and the suction force is required to be strong in a wide air volume range.
The fan of patent document 1 has a curved flow path formed downstream of the impeller to turn the radial wind speed in the axial direction, and a stationary blade extending in the axial direction is provided downstream of the curved flow path. When the technique of patent document 1 is applied to an electric fan mounted in a vacuum cleaner which is required to be downsized, there is a problem that the wind speed at the bent portion is high, the pressure loss at the bent portion is increased, and the performance is degraded. In order to reduce the pressure loss at the curved portion, it is considered effective to increase the radial distance between the impeller (impeller) and the curved portion, but there is a problem that the outer diameter of the fan becomes large and the product becomes large.
The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a small-sized and lightweight electric blower having high efficiency over a wide air flow rate range, and a small-sized electric vacuum cleaner having improved suction force over a wide air flow rate range.
[ means for solving the problems ]
In order to solve the above-described problems and achieve the above-described object, for example, the configuration described in the summary of the invention is adopted.
The present invention includes a plurality of technical means for solving the above-mentioned technical problems, and for example, the present invention provides an electric blower including: an electric motor having a rotor and a stator; a rotating shaft provided to the rotor; a rotary blade fixed to the rotary shaft; a centrifugal diffuser having a plurality of centrifugal diffuser blades formed radially on the outer peripheral side of the rotary blade; and a fan casing covering the impeller, wherein an axial flow type diffuser blade having a blade height formed in a radial direction is provided downstream of the centrifugal diffuser blade.
[ effect of the invention ]
According to the present invention, a small-sized and light (weight) electric blower having high efficiency in a wide air volume range can be realized. Further, a small-sized vacuum cleaner having improved suction force in a wide air volume region can be realized.
Other technical problems, structures, and effects than those described above will be apparent from the following description of the embodiments.
Drawings
Fig. 1(a) is an external view of an electric blower according to embodiment 1 of the present invention.
Fig. 1(b) is a longitudinal sectional view of the electric blower.
Fig. 2(a) is a perspective view of an impeller in embodiment 1 of the present invention, and (b) is a vertical sectional view of the impeller.
Fig. 3 is a view showing a fan unit according to embodiment 1 of the present invention, and is a sectional view taken along line a-a of the electric fan of fig. 1 (a).
Fig. 4 is a view showing a diffuser portion of a fan according to embodiment 1 of the present invention.
Fig. 5 is a diagram showing a fan case of a fan according to embodiment 1 of the present invention.
Fig. 6 is a graph comparing fan efficiencies (fluid analysis results) of a fan in an embodiment of the present invention and a fan having only axial-flow diffuser blades.
Fig. 7 is a view showing a diffuser portion of a fan according to embodiment 2 of the present invention.
Fig. 8 is a perspective view of an electric vacuum cleaner to which an electric blower according to an embodiment of the present invention is applied.
Fig. 9 is a sectional view of a cleaner body of the electric cleaner of fig. 8.
Detailed Description
An embodiment of the present invention will be described below with reference to the drawings.
[ example 1]
Referring to fig. 8 and 9, a vacuum cleaner 300 according to an embodiment of the present invention will be described. Fig. 8 is a perspective view of an electric vacuum cleaner to which the electric blower of the present embodiment is applied. As shown in fig. 8, 100 is a cleaner body which houses a dust collecting chamber 101 for collecting dust and an electric fan 200 (fig. 1) for generating a suction airflow necessary for dust collection, 102 is a holding portion for attaching the cleaner body 100, 103 is a handle portion provided at one end of the holding portion 102, and 104 is a switch portion provided at the handle portion for turning on/off the electric fan 200. A suction port body 105 is attached to the other end of the holding portion 102, and the cleaner main body 100 and the suction port body 105 are connected by a connecting portion 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 handle unit 103 is operated, the electric fan 200 housed in the cleaner body 100 is operated to generate a suction airflow. Dust is sucked from the suction body 105 and collected into the dust collecting chamber 101 of the cleaner body 100 through the connecting portion 106.
Next, the dust collector main body 100 will be described with reference to a cross-sectional view schematically showing the dust collector main body 100 of the electric vacuum cleaner shown in fig. 9. Inside the cleaner body 100, an electric fan 200 for generating suction force, a battery unit 108 for driving the electric fan 200, a driving circuit 109, and a dust collecting chamber 101 are disposed.
The cleaner main body 100 is detachable from the holding portion 102 and is used as a hand-held cleaner, and the main body handle portion 110 and the suction opening 111 are provided in the cleaner main body 100. Reference numeral 112 (fig. 8) denotes a main body switch unit for turning on/off the electric fan 200 when the hand-held cleaner is used. The main body switch 112 can be operated even when the cleaner main body 100 is attached to the holding portion 102. Fig. 8 and 9 show a cordless (rechargeable) vacuum cleaner in which the suction port opening 111 and the connection portion 106 can be detached, but a vacuum cleaner with a power cord without 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. 1(a) and a vertical cross-sectional view of the electric blower shown in fig. 1 (b). The electric blower 200 is roughly divided into a blower part 201 and a motor part 202. The fan section 201 includes: an impeller 1 as a rotating blade; a partition plate 2 disposed on the back surface of the impeller 1, i.e., on the motor portion 202 side, and forming a hub surface of the centrifugal diffuser blade in the 1 st row (row) on the outer periphery of the impeller; 2 rows of centrifugal diffuser blades 23 and 24 arranged in the radial direction on the outer peripheral portion of the impeller 1; and a resin fan case 3 covering the impeller. The partition plate 2 forms a curved flow path 25 that turns the airflow in the radial direction in the axial direction on the inner surface of the fan case 3 and the outer peripheral end 2a of the partition plate 2. An air inlet 4 is provided on the upper surface of the fan case 3. The impeller 1 is made of thermoplastic resin and is directly connected to the rotating shaft 5. Here, although the impeller 1 as the rotary blade is press-fitted and fixed to the rotary shaft 5 in the present embodiment, the impeller 1 may be fixed by a fixing nut by providing a screw at an end of the rotary shaft 5.
The motor portion 202 includes: a rotor core 7 housed in the motor case 9 and fixed to the rotary shaft 5; and a stator core 8 at an outer peripheral portion thereof. A winding is wound around stator core 8, and the winding is electrically connected to a driving circuit 109 provided in electric fan 200.
The rotor core 7 is made of rare earth bonded magnets. The rare earth bonded magnet is produced by mixing rare earth magnetic powder and an organic binder. As the rare earth-based bonded magnet, for example, a samarium-iron-nitrogen magnet, a neodymium magnet, or the like can be used. The rotor core 7 is formed integrally with the rotary shaft 5 or fixed to the rotary shaft 5.
In the present embodiment, a permanent magnet is used for the rotor core 7, but the present invention is not limited to this, and a reluctance motor or the like which is a kind of a commutatorless motor may be used.
A bearing 10 is provided between the impeller 1 and the rotor core 7, and a bearing 11 is provided on the opposite side of the rotor core 7 in the rotation axis direction to rotatably support the rotation axis 5. Motor case 9 is made of metal and is fixed to bearing case 34 supporting bearing 11.
Screw holes 15 extending in the direction of the rotation axis are formed in the end of the metal motor case 9. Fixing screws 16 are screwed into screw holes 15, and partition plate 2 is fixedly provided to metal motor case 9 by screwing of fixing screws 16.
The minimum area of the circular flow path formed between the inner surface 3a of the fan case 3 and the outer circumferential end 2a of the partition plate 2 is set to be larger than the outlet area of the impeller 1. With such a configuration, an increase in the wind speed and the pressure loss of the circular flow path portion can be suppressed.
The centrifugal diffuser vane 23 closest to the rotary vane on the partition plate 2 is provided in a plurality of pieces in the circumferential direction around the rotary shaft 5. The centrifugal diffuser blades 24 of the subsequent stage are provided in a plurality of pieces in the circumferential direction around the rotary shaft 5 at the outer peripheral portion of the centrifugal diffuser blades 23. The radial position of the leading edge 24a of the 2 nd row centrifugal diffuser blade 24 is larger than the outer peripheral end of the hub surface of the centrifugal diffuser blade 23 (the outer peripheral end 2a of the partition plate 2) close to the rotor blade, and the centrifugal diffuser blade 24 extends from the outer peripheral end 2a of the partition plate 2 to the curved flow path 25. In the partition plate 2, the axial-flow type diffuser blades 12 located downstream of the centrifugal type diffuser blades 24 are provided in plural pieces with the rotation axis as the center.
An annular ring 6 is provided on a shroud (radially outer end of the blade) of the axial flow diffuser blade 12, and the fan case 3 is fixed to the ring 6.
Vibration-proof rubber 19 is provided in the installation parts of the fan case 3 and the cleaner body, and vibration of the electric fan is suppressed and air leakage between the fan case 3 and the installation parts of the cleaner body is prevented, thereby achieving noise reduction and high efficiency. The electric fan is fixed to the cleaner body by a support portion 14 extending in the axial direction from the partition plate 2.
In the design point of the centrifugal diffuser vane 23 of the partition plate 2, the air flow flowing out from the impeller 1 is made to substantially match the vane inlet angle, so that the rotational direction velocity component of the air flow is reduced by the centrifugal diffuser vane 23, thereby improving the diffuser effect and the fan efficiency. The centrifugal diffuser vane 24 provided on the outer periphery of the centrifugal diffuser vane 23 further reduces the rotational direction velocity component of the airflow flowing out from the centrifugal diffuser vane 23 to divert the airflow in the axial direction, thereby suppressing the pressure loss generated in the curved flow path. Further, the axial-flow diffuser blade 12 effectively reduces the rotational-direction velocity component existing in the axial-flow air flowing out from the centrifugal diffuser blade 24 by the blade-type shape, and can further improve the fan efficiency. In the shroud of the axial-flow diffuser blade 12, since the flow velocity of the air flow on the fan casing side (3a side) of the centrifugal diffuser blade 24 is high, the blade chord length (chord length) can be shortened (the blade leading edge 12a and the blade trailing edge 12b) and the blade chord length can be increased on the hub side (2a side) where the flow velocity is low, and the air flow is slowly diverted, thereby effectively reducing the rotational direction velocity component.
Next, the flow of air in electric fan 200 will be described. When the motor portion 202 is driven to rotate the impeller 1 as a rotating blade, air flows in from the air inlet 4 of the fan case 3 and flows into the impeller 1. The air flowing in is pressurized and accelerated in the impeller 1, and flows out from the outer periphery of the impeller 1. When the air flow flowing out of the impeller 1 passes through the centrifugal diffuser blades 23 and 24, the air flow flows along the blades, and thereby the rotational direction velocity component of the air flow can be reduced. Further, the airflow passing through the centrifugal diffuser blades 24 is turned in the axial direction, flows into the axial diffuser blades 12 through the curved flow path 25 formed by the inner surface of the fan case 3 and the outer circumferential end 2a of the partition plate 2, and flows along the blades, whereby the rotational direction velocity component of the airflow can be further reduced and the airflow can be discharged.
Next, a fan unit 201 of an example of the present embodiment will be described with reference to fig. 2 and 3. Fig. 2(a) is a perspective view of an impeller according to an embodiment of the present invention, (b) is a sectional view of the impeller, and fig. 3 is a blower unit according to an embodiment of the present invention, which is a sectional view taken along line a-a of the electric blower of fig. 1 (a).
First, an impeller 1 as a rotary blade according to an embodiment of the present invention will be described with reference to fig. 2. The impeller 1 of one embodiment of the present invention is constituted by 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 cover plate 33 made of thermoplastic resin has an annular suction opening 28 formed in the center thereof for sucking air.
A concave groove 29 is formed in the flow path surface of the shroud plate 33 at a position corresponding to the vane 27, and the concave groove 29 is provided to extend to the outer diameter side. The concave groove 29 is provided with a through hole 30. A convex hub 31 is formed at the center of the hub plate 26, and the rotary shaft 5 is inserted into and fixed to the hub 31. The blades 27 integrally formed with the hub plate 26 are provided at equal intervals in the circumferential direction, and have a blade shape that retreats in the rotational direction as it goes from the inner diameter side to the radial outer side. The hub 31 is formed with a hub curved surface 31a radially outward from the axial direction. A projection-shaped claw 32 and a welding rib are formed on the upper surface of the blade 27. The impeller 1 is formed by engaging the protruding claws 32 of the blades 27 with the through holes 30 of the shroud plate 33, engaging the concave grooves 29 of the shroud plate 33 with the blades 27, and joining the claws 32 and the welding ribs by welding.
Since the welding rib is melted in the concave groove 29, the volume of the welding rib is made smaller than the volume of the gap when the blade 27 is inserted into the concave groove 29. That is, the melted resin material can be prevented from overflowing into the flow path of the impeller 1. Further, since the welding ribs of the blades 27 are melted and welded to the shroud plate 33, leakage 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 position of the shroud plate 33 and the vane 27, but the present invention is not limited to this, and may be a recess shape without passing through, and any shape may be used as long as the shroud plate 33 and the vane 27 can be positioned by being fitted to the claw 32 of the vane 27. Further, the boss 26a is provided on the outer periphery of the hub plate 26 on the back side of the blade 27, and the balance correction can be performed by rotating the impeller 1 and cutting off the boss 26 a. By adopting the above structure, the unbalance amount of the impeller 1 can be reduced, and vibration and noise can be reduced. Although fig. 2 shows a closed centrifugal impeller provided with a shroud plate 33, the hub curved surface 31a may be a diagonal flow impeller inclined with respect to the axial direction as it goes to the outer peripheral portion of the impeller, regardless of the presence or absence of an open centrifugal impeller and a shroud plate not provided with a shroud plate 33.
Next, a fan 201 according to an embodiment of the present invention will be described with reference to fig. 1 and 3 to 5.
In the fan 201 according to an embodiment of the present invention, 15 centrifugal diffuser blades 23 are provided at equal intervals in the circumferential direction on the outer peripheral portion of the impeller 1 as a rotating blade. The centrifugal diffuser vane 23 is formed in a vane shape extending from the partition plate 2 toward the fan casing and is formed integrally with the partition plate 2 (fig. 4). The ring 6 is integrally formed with the axial-flow diffuser blades 12 extending from the bulkhead 2 in the substantially radial direction. In fig. 4, a part of the ring 6 is removed to show the shape of the axial flow diffuser blade 12 for ease of explanation. The centrifugal diffuser vanes 24 are provided in the same number as the number of the centrifugal diffuser vanes 23 in the outer peripheral portion of the centrifugal diffuser vanes 23. Fig. 5 is a perspective view of the fan case 3 viewed from the motor side.
The centrifugal diffuser blades 24 are formed in a height direction from the intake opening 28 side of the fan case 3 toward the partition plate 2, and are integrally molded with the fan case 3 by resin. The leading edge 24a of the centrifugal diffuser vane 24 is located radially closer to the outer periphery than the outer peripheral end 2a of the diaphragm 2. That is, the centrifugal diffuser vane 24 is located radially outward of the outer peripheral end 2a of the diaphragm 2.
The trailing edge 24b of the centrifugal diffuser vane 24 is integral with the inner surface 3a of the fan case 3, and a fillet (angle R) is provided on the rotation direction retreating side 24c of the angle at which the trailing edge 24b of the centrifugal diffuser vane 24 contacts the fan case inner surface 3 a. By providing the fillet on the retreated side 24c, the rotational direction velocity component of the airflow on the trailing edge side of the centrifugal diffuser vane 24 is reduced, and the axial airflow is promoted by the draft angle at the time of forming the fillet, thereby suppressing the pressure loss of the airflow generated in the curved flow path 25. Further, by increasing the radius of the receding side 24c, sink marks can be prevented from being generated at the time of molding.
Here, the axial positional relationship of the centrifugal diffuser vanes will be described.
The ratio b3/b2 of the inlet height b3 of the centrifugal diffuser (the axial dimension of the fan case side of the partition plate 2, the hub plate of the centrifugal diffuser blade leading edge, and the fan case 3 b) to the flow path height at the outermost diameter of the rotary blade (the outlet height b2) is set to approximately 1.0 to 1.2, and the axial positions of the hub surface of the centrifugal diffuser and the hub plate of the rotary blade are approximately matched. With such a configuration, the airflow can be decelerated at the inlet of the centrifugal diffuser, so that the efficiency can be improved, and the performance variation in the axial position of the rotary blade, which is likely to occur in mass production, can be reduced. Further, the ratio D3/D2 between the inlet diameter D3 of the centrifugal diffuser and the outermost diameter D2 of the rotary blade is set to about 1.1, and high efficiency and low noise are achieved. The axial end 24d of the leading edge of the centrifugal diffuser blade 24 is located on the suction side or substantially at the same axial position as the outer peripheral end 2b of the hub surface constituting the partition plate 2, and the axial end 24e of the trailing edge of the centrifugal diffuser blade 24 is located on the motor side with respect to the outer peripheral end 2b of the hub surface constituting the partition plate 2. With such a configuration, the airflow that collides with the fan case can be guided, and the airflow can be effectively diverted in the axial direction, thereby suppressing the pressure loss of the airflow generated at the bent portion of the bent flow path 25.
Here, the centrifugal diffuser vane shape will be explained. The chord length of the centrifugal diffuser vane 23 (the length between the connection leading edge 23a and the connection trailing edge 23b of the diffuser vane 23) is longer than the chord length of the centrifugal diffuser vane 24 (the length between the connection leading edge 24a and the connection trailing edge 24b of the centrifugal diffuser vane 24), and the diffuser vane 23 close to the impeller increases the turning direction of the airflow. The circumferential positions of the centrifugal diffuser vane 23 and the succeeding centrifugal diffuser vane 24 are set such that an angle θ formed by a line connecting the trailing edge 23b of the centrifugal diffuser vane 23 and the rotation axis center 5a and a line connecting the leading edge 24a of the centrifugal diffuser vane 24 and the rotation axis center 5a is about 9% of the circumferential attachment interval of the centrifugal diffuser vane (a value obtained by dividing 360 ° by the number of vanes) and the leading edge 24a of the succeeding centrifugal diffuser vane 24 is located in a position opposite to the trailing edge 23b of the centrifugal diffuser vane 23. Further, the blade chord of the centrifugal diffuser blade 24 is substantially parallel to the blade chord of the centrifugal diffuser blade 23.
The centrifugal diffuser vane 23 has a vane shape in which the solidity (ソリディティ) obtained by dividing the vane chord length C (the length of the connection leading edge 23a and trailing edge 23b of the centrifugal diffuser vane 23) by the distance in the circumferential direction of the vane attachment interval is about 1. The solidity may be about 1 to 1.3, and if the solidity is 1 or more, the throat 13 may be formed by the adjacent blades, and the throat 13 may be formed on the trailing edge 23b side of the center of the blade chord length of the adjacent blade, thereby achieving high efficiency.
The maximum thickness ratio of the maximum thickness t of the centrifugal diffuser blade divided by the diffuser blade chord length C is set to 8 to 25%, and the centrifugal diffuser blade 23 and the diffuser blade 24 are set to the same value (except for the plate thickness formed by the angle R formed by the trailing edge 24b of the diffuser blade and the inner surface 3a of the fan casing). That is, the maximum blade thickness of the centrifugal diffuser blades 23 near the impeller is made thicker than the centrifugal diffuser blades 24 at the subsequent stage. With such a configuration, even when the fan is operated under unstable conditions such as whirling stall that is likely to occur under operating conditions on the low air flow side of the design point air flow rate, damage to the blades due to repeated stress can be prevented.
The maximum thickness of the blade is ensured to be more than 0.7mm, and sink marks during forming are prevented, and performance deviation during production is reduced. The minimum thickness of the centrifugal diffuser vanes 23 and 24 is set to 4% or more of the chord length of the vanes, thereby preventing resin chipping during molding.
The centrifugal diffuser vane 23 described with reference to fig. 4 to 5 is formed integrally with the partition plate 2, the centrifugal diffuser vane 24 is formed integrally with the fan case, and the centrifugal diffuser vane 23 close to the impeller and the diffuser vane 24 at the subsequent stage are formed at different positions. By using a sealing material or a different soft material (for example, synthetic rubber) to contact the contact surface 3b between the fan case 3 and the centrifugal diffuser vane 23, leakage flow between the centrifugal diffuser vanes can be suppressed, and high efficiency can be achieved. In order to suppress the leakage flow between the centrifugal diffuser blades, it is preferable that the blade ends of the centrifugal diffuser blades 23 come into surface contact with the contact surface 3b of the fan case 3 or sink into the contact surface 3b of the fan case 3.
The number of the centrifugal diffuser blades 23 and 24, the number of the protrusions 20 at the end of the fan case 3, and the number of the mounting holes 21 for fixing the fan case 3 to the case 6 are made the greatest common divisor of each other, and the circumferential positions of the diffuser blades 23 and 24 are set to predetermined positions, so that there is no difference between the circumferential positions at the time of assembly, thereby improving the performance of mass production. The number of the blades of the centrifugal diffuser in the embodiment is 15, but 13 to 19 blades may be used. When the number of the centrifugal diffuser blades is large, the centrifugal diffuser blades 23 close to the impeller and the centrifugal diffuser blades 24 at the subsequent stage may have substantially the same blade length and maximum thickness.
Next, the structure of the axial-flow type diffuser blade 12 located downstream of the centrifugal diffuser blade 24 will be described. The axial-flow diffuser blades 12 have blade heights extending outward from the hub surface of the diaphragm 2 in a substantially radial direction, and are provided in plural numbers around the rotation axis. The number of blades of the axial-flow diffuser blades 12 is preferably the same as the number of blades of the centrifugal diffuser blades 24. The axial-flow diffuser blades 12 are arranged to overlap the centrifugal diffuser blades 24 of the final stage in the radial direction when viewed from the axial suction side. The trailing edge of the axial-flow diffuser blade 12 (the end 12b on the downstream side in the axial direction of the blade) is provided so as to intersect the blade chord of the centrifugal diffuser blade 24 when viewed in the axial direction. Since the axial-flow diffuser blades 12 and the centrifugal diffuser blades 24 overlap in the radial direction and the airflow passing through the radial direction outer side (3a side) of the fan case 3 of the centrifugal diffuser blades 24 flows out along the centrifugal diffuser blades 24, the rotational direction velocity component on the shroud side of the axial-flow diffuser blades 12 can be effectively reduced, the efficiency can be improved, and the size can be reduced.
Here, the shape of the axial diffuser blade 12 will be explained. The blade chord length 12d on the hub side (the blade root 2a integral with the diaphragm 2) of the axial-flow diffuser blade 12 is longer than the shroud (the radially outer side 12c of the blade). That is, the turning of the airflow is made gentle by increasing the chord length of the blade on the hub side. The circumferential position of the hub-side leading edge of the axial-flow diffuser blade 12 substantially coincides with the leading edge of the centrifugal diffuser blade 24. By making the circumferential position of the hub-side front edge of the axial-flow diffuser blade 12 substantially coincide with the front edge of the centrifugal diffuser blade 24, the turning of the hub-side airflow is gentle, and the separation of the hub-side airflow can be suppressed, thereby improving the efficiency.
The shroud outlet angle β s of the axial flow diffuser blade 12 is set to be substantially axial, and the hub outlet angle β h is a shape having a larger outlet angle from the axial direction than the shroud. That is, the axial-flow diffuser blade 12 is twisted in the blade height direction and has a shape in which the blade chord length is shortened from the hub side to the shroud side. As the shape twisted in the height direction of the axial flow diffuser blade 12, by orienting the shroud-side outlet angle in the axial direction, it is possible to largely turn on the shroud side where the airflow is easily turned, and to suppress turning on the hub side where the airflow is easily deviated, and it is possible to achieve high efficiency in a wide operating range. When the outlet angle coincides with the axial direction, the rotational direction component velocity can be reduced.
When the turning angle of the axial flow diffuser 12 is small, even if the same axial flow diffuser blades as the axial flow diffuser 12 are provided downstream of the axial flow diffuser blades 12, the speed of the rotational direction speed component can be reduced efficiently in the axial direction of the axial flow diffuser blades of 2 rows, and high efficiency can be achieved in a wide operating range.
The axial-flow diffuser blade 12 has a blade shape in which the solidity obtained by dividing the blade chord length C (the length of the shroud connected from the leading edge 12a to the trailing edge 12b of the axial-flow diffuser blade 12) by the distance in the circumferential direction of the blade attachment interval is about 1 or less in both the shroud and the hub, and the shroud has a small solidity. If the solidity is 1 or less, the blade shape can be molded by a resin molded article, and the cost can be reduced because the mold structure is easily formed.
The maximum thickness ratio obtained by dividing the maximum thickness t of the axial-flow diffuser blade 12 by the diffuser blade chord length C is 8-25%. Further, by securing the maximum thickness of the blade to 0.7mm or more, sink marks can be prevented from being generated during molding, and variations in performance can be reduced during mass production. The minimum thickness of the axial-flow diffuser blade 12 is set to 4% or more of the chord length of the blade, and the occurrence of resin chipping is prevented during molding.
In the present embodiment, as an example, a diffuser blade of a structure having 2 rows of centrifugal diffuser blades in the radial direction downstream of the impeller and having an axial diffuser blade downstream thereof has been described, so that there are 3 rows of centrifugal and axial flow. Each diffuser blade has an aspect ratio (chordal/temperate ratio) of 1 or less, and a diffuser blade having 3 rows with an aspect ratio of 1 or less is described. Wherein, the degree of solidity can be about 1 to 1.3, if the degree of solidity is more than 1, the adjacent blade can be used to form the throat, and high efficiency can be realized.
Here, the axial positional relationship of the blades of the axial-flow diffuser will be described.
The axial position of the leading edge 12a of the axial-flow diffuser blade 12 on the hub side is S or less (shown in fig. 3 and 4) and the clearance of the curved flow path is S or less at the axial downstream side from the axial position having the outermost diameter 2b of the hub surface of the centrifugal diffuser blade 23. With such a configuration, the air flow is diverted by the centrifugal diffuser blades 24 and then flows into the axial diffuser blades 12 before being separated, so that the pressure loss of the air flow due to the rotational direction velocity component can be reduced, and high efficiency can be achieved in a wide operating range.
In the shroud of the axial flow diffuser blade 12, an annular ring 6 is provided on the trailing edge side of the shroud, and a blade end 12e on the leading edge side of the shroud protrudes. The position on the suction side of the annular ring 6 substantially coincides with the maximum blade thickness position of the shroud. By adopting such a configuration, the inner surface 3a of the fan case 3 and the maximum thickness position are provided, and the concentricity of the shafts can be secured, thereby improving the assembling convenience.
The ring 6 is provided with claw-like projections 22 in the circumferential direction 3, and is fitted into and connected to the mounting hole 21 of the fan case 3. The axial-flow diffuser blade 17 located at the claw-like projection 22 can suppress an increase in the outer diameter of the fan due to the claw structure by reducing the blade height as compared with the other axial-flow diffuser blades 12, thereby achieving a reduction in the size of the fan.
Here, fig. 6 shows a comparison of fan efficiency between the fan of the present embodiment having the centrifugal diffuser blades 23, the centrifugal diffuser blades 24, and the axial diffuser blades 12 and the fan of the related art having a curved flow path downstream of the impeller and an axial diffuser blade downstream of the curved flow path as in the related art. In fig. 6, the abscissa represents a dimensionless air volume with a design point air volume of 1, and the ordinate represents the fluid analysis result of the fan efficiency. Here, the fan efficiency in fig. 6 is defined as the product of the suction volume flow rate and the static pressure rise at the inlet and outlet of the fan divided by the shaft power of the fan. As is apparent from fig. 6, the fan of the present embodiment in which 2 rows of the centrifugal diffuser blades of the present embodiment are provided in the radial direction and the axial-flow diffuser blades are mounted can improve the fan efficiency over a wider operating range than the fan of the related art. That is, it is found that high efficiency can be maintained over a wide operating range by arranging 2 rows of centrifugal diffuser blades and mounting the axial flow type diffuser blades 12 on the rear stage of the centrifugal diffuser. In the present embodiment, the centrifugal diffuser blades 24 and the axial diffuser blades 12 are arranged to overlap in the radial direction when viewed from the suction side, and the size can be reduced.
In accordance with the electric blower 200 of the example of the present embodiment described above, the electric blower 200 includes: an electric motor having a rotor and a stator; a rotating shaft provided to the rotor; a rotary blade fixed to the rotary shaft; a centrifugal diffuser having a plurality of centrifugal diffuser blades formed radially on the outer peripheral side of the rotary blade; and a fan case covering the impeller, wherein an axial flow type diffuser blade forming a blade height is provided in a radial direction downstream of the centrifugal diffuser blade, and by adopting such a configuration, an electric fan can be obtained which further reduces a rotational direction velocity component of an air flow flowing out from the centrifugal diffuser blade 24 by the axial flow type diffuser blade 12, suppresses a pressure loss generated at the exhaust port 18, contributes to improvement of fan efficiency, and is high in efficiency, small in size, and light in a wide air volume region.
[ example 2]
Next, embodiment 2 will be described with reference to fig. 7. Fig. 7 is a perspective view of a diffuser portion of a fan according to embodiment 2 of the present invention. Since the basic configuration is the same as that of embodiment 1 described above, the same reference numerals are used for the same elements, and the description thereof is omitted.
In the present embodiment, the partition plate 2 is provided with the centrifugal diffuser blades 23 and the axial diffuser blades 12, and the axial diffuser blades 35 located downstream thereof. The axial-flow diffuser blades 12 have blade heights extending outward in a substantially radial direction from a hub surface of the partition plate 2, and a plurality of axial-flow diffuser blades 12 are provided around the rotation axis. The axial flow type diffuser blades 35 extend radially outward from a hub 36 having the same flow path as the hub surface 2a of the axial flow type diffuser blades 12. The boss 36 is fixed to the bulkhead 2 by an engaging structure such as adhesion, welding, or claw-like projection 22. The number of blades of the axial-flow diffuser blade 12 and the axial-flow diffuser 35 is preferably the same as that of the centrifugal diffuser blade 23. Although the present embodiment has been described using the centrifugal diffuser vane 23 integrated with the partition plate 2, the centrifugal diffuser vane 24 integrated with the fan case 3 shown in fig. 5 may be used.
The axial flow diffuser blades 35 effectively reduce the velocity component in the rotational direction of the air flow flowing through the axial flow diffuser 12, suppress the pressure loss generated at the exhaust port 18, and achieve high efficiency over a wide operating range.
The electric blower 200 according to the present embodiment described above includes: an electric motor having a rotor and a stator; a rotating shaft provided to the rotor; a rotary blade fixed to the rotary shaft; a centrifugal diffuser having centrifugal diffuser blades on the outer peripheral side of the rotary blades; and a fan case covering the impeller, wherein a plurality of rows of axial flow type diffuser blades having a blade height in the radial direction are provided in the axial direction at the downstream of the centrifugal diffuser blades, and by adopting such a configuration, an electric fan can be obtained which further reduces the rotational direction velocity component of the air flow flowing out from the centrifugal diffuser blades 23 or the centrifugal diffuser blades 24 by the axial flow type diffuser blades 12 and the axial flow type diffuser blades 35 at the downstream thereof, suppresses the pressure loss generated at the exhaust port 18, contributes to the improvement of the fan efficiency, and is highly efficient, small-sized, and lightweight in a wide air volume region.
The present invention is not limited to the above-described embodiments, and various modifications are possible.
For example, the above-described embodiments have been described in detail to explain the present invention easily and understandably, and are not limited to having all the structures described. A part of the structure of one embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of one embodiment. In addition, some of the configurations of the embodiments may be added, deleted, or replaced with other configurations.
[ description of reference numerals ]
1 impeller
2 partition board
2a outer peripheral end of the separator
2b outer peripheral end of hub surface of partition plate
3 Fan case
Inner surface of 3a fan case
3b at the surface of the fan casing in contact with the diffuser blades
4 air suction inlet
5 rotating shaft
5a center of the rotation axis
6 Ring
7 rotor core
8 stator core
9 Motor casing
10 bearing
11 bearing
12 axial flow diffuser vane
13 throat part
14 support part
15 screw hole
16 screw
17 axial flow diffuser vane with protrusion
18 exhaust port
19 vibration-proof rubber
20 protrusion
21 mounting hole
22 claw-shaped protrusion
23 impeller-side diffuser vane
23a leading edge of diffuser vane on impeller side
23b trailing edge of diffuser vane on impeller side
23c diffuser vane and baffle contact surface
24 rear stage diffuser vane
24a leading edge of diffuser vane of the latter stage
24b trailing edge of diffuser vane of the latter stage
24c fillet of corner (retreating side in rotation direction) where diffuser blade of the latter stage contacts fan case
Axial end of leading edge of 24d rear stage diffuser vane
Axial end of trailing edge of 24e rear stage diffuser vane
25 curved flow path
26 hub plate
26a convex part
27 blade
28 suction opening
29 concave groove
30 through hole
31 wheel hub
31a hub camber
32 claw
33 protective cover
34 bearing shell
35 axial flow diffuser
Hub of 36 axial-flow diffuser
100 electric vacuum cleaner main body
200 electric fan
201 blower part
202 motor unit
Claims (10)
1. An electric blower, comprising:
an electric motor having a rotor and a stator;
a rotating shaft provided to the rotor;
a rotary blade fixed to the rotary shaft;
a centrifugal diffuser having a plurality of centrifugal diffuser blades formed radially on the outer peripheral side of the rotary blade; and
a fan case covering the impeller is provided with a fan,
an axial flow diffuser having axial flow diffuser blades forming a blade height in a radial direction is provided downstream of a centrifugal diffuser blade of a last stage farthest from a center of a rotation shaft among the plurality of centrifugal diffuser blades,
the axial flow diffuser blade overlaps with the centrifugal diffuser blade of the final stage in a radial direction when viewed from an intake side in an axial direction,
a centrifugal diffuser vane closest to the center of the rotating shaft among the plurality of centrifugal diffuser vanes is provided in the partition plate,
the centrifugal diffuser vane of the last stage is disposed in the curved flow path, and the leading end of the vane is disposed so as not to overlap the partition in the axial direction.
2. An electric blower, comprising:
an electric motor having a rotor and a stator;
a rotating shaft provided to the rotor;
a rotary blade fixed to the rotary shaft;
a plurality of centrifugal diffusers each having a centrifugal diffuser blade on an outer peripheral side of the rotating blade; and
a fan case covering the impeller is provided with a fan,
a plurality of rows of axial-flow diffusers are arranged in the axial direction downstream of the centrifugal diffuser blades, the axial-flow diffusers have axial-flow diffuser blades with blade heights formed in the radial direction,
a trailing edge of the centrifugal diffuser vane is formed integrally with an inner surface of the fan case, the trailing edge of the centrifugal diffuser vane has a rounded corner on a rotation direction retreating side of a corner in contact with the inner surface of the fan case,
a centrifugal diffuser vane closest to the center of the rotating shaft among the plurality of centrifugal diffuser vanes is provided in the partition plate,
the centrifugal diffuser vane of the last stage, which is farthest from the center of the rotating shaft, among the plurality of centrifugal diffuser vanes is disposed in the curved flow path, and the leading end of the vane is disposed so as not to overlap the partition in the axial direction.
3. An electric blower, comprising:
an electric motor having a rotor and a stator;
a rotating shaft provided to the rotor;
a rotary blade fixed to the rotary shaft;
a centrifugal diffuser having centrifugal diffuser blades on the outer peripheral side of the rotating blades; and
a fan case covering the impeller is provided with a fan,
an axial flow diffuser is arranged downstream of the centrifugal diffuser blades, the axial flow diffuser having axial flow diffuser blades forming a blade height in the radial direction,
there are provided 3 rows of diffuser blades in the direction of the air flow consisting of 2 rows of centrifugal diffuser blades and 1 row of axial flow diffuser blades in the radial direction,
in a cross section centered on the rotation axis, the first centrifugal diffuser blade is disposed at a distance from the second centrifugal diffuser blade and the axial diffuser blade, the second centrifugal diffuser blade and the axial diffuser blade overlap each other when viewed in the axial direction,
the first centrifugal diffuser vane of the 3 rows of diffuser vanes is disposed at the position closest to the center of the rotating shaft.
4. The electric blower according to any one of claims 1 to 3, wherein:
a curved portion for deflecting an air flow from a radial direction to an axial direction is provided between the centrifugal diffuser and the axial flow diffuser.
5. The electric blower according to any one of claims 1 to 3, wherein:
some or all of the centrifugal diffuser and the axial flow diffuser have diffuser blades having an aspect ratio of 1 or less.
6. The electric blower according to any one of claims 1 to 3, wherein:
the axial flow diffuser blade has a hub blade chord length longer than the shroud.
7. The electric blower according to any one of claims 1 to 3, wherein:
a portion of the shroud of the axial flow diffuser blade contacts the inner surface of the fan case.
8. The electric blower according to any one of claims 1 to 3, wherein:
a blade chord of a centrifugal diffuser blade of a last stage farthest from a center of the rotation shaft among the plurality of centrifugal diffuser blades intersects with a trailing edge of the axial diffuser blade.
9. The electric blower according to any one of claims 1 to 3, wherein:
the centrifugal diffuser blades closest to the impeller and the axial diffuser blades are formed as one body.
10. An electric vacuum cleaner, characterized in that:
an electric blower according to any one of claims 1 to 9.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019-005673 | 2019-01-17 | ||
| JP2019005673A JP2020112145A (en) | 2019-01-17 | 2019-01-17 | Electric blower and vacuum cleaner with the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN111441969A CN111441969A (en) | 2020-07-24 |
| CN111441969B true CN111441969B (en) | 2022-02-22 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201910823879.2A Active CN111441969B (en) | 2019-01-17 | 2019-09-02 | Electric fan and electric dust collector with same |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP2020112145A (en) |
| CN (1) | CN111441969B (en) |
| TW (1) | TWI723518B (en) |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114183402A (en) * | 2020-09-14 | 2022-03-15 | 北京石头世纪科技股份有限公司 | Fan and cleaning equipment |
| KR20240040818A (en) * | 2021-09-06 | 2024-03-28 | 광동 웰링 모터 매뉴팩처링 컴퍼니, 리미티드 | Electric blowers and cleaning devices |
| CN114876876A (en) * | 2022-06-29 | 2022-08-09 | 沈阳鼓风机集团核电泵业有限公司 | Pumping chamber and centrifugal pump |
| JP2024011656A (en) * | 2022-07-15 | 2024-01-25 | 日立グローバルライフソリューションズ株式会社 | Electrically-driven air blower and vacuum cleaner with the same |
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| CN1724878A (en) * | 2004-07-20 | 2006-01-25 | Lg电子株式会社 | Centrifugal fan and vacuum cleaner having the centrifugal fan |
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| GB2467968B (en) * | 2009-02-24 | 2015-04-22 | Dyson Technology Ltd | Centrifugal compressor with a diffuser |
| JP2011080427A (en) * | 2009-10-08 | 2011-04-21 | Panasonic Corp | Electric blower and vacuum cleaner using the same |
| CN206190606U (en) * | 2016-10-18 | 2017-05-24 | 美的集团股份有限公司 | Centrifugal fan and dust catcher that has it |
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2019
- 2019-01-17 JP JP2019005673A patent/JP2020112145A/en active Pending
- 2019-08-30 TW TW108131177A patent/TWI723518B/en active
- 2019-09-02 CN CN201910823879.2A patent/CN111441969B/en active Active
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| CN1724878A (en) * | 2004-07-20 | 2006-01-25 | Lg电子株式会社 | Centrifugal fan and vacuum cleaner having the centrifugal fan |
| KR20060026343A (en) * | 2004-09-20 | 2006-03-23 | 엘지전자 주식회사 | Guide vane structure of fan-motor for vacuum cleaner |
| CN103889295A (en) * | 2011-10-13 | 2014-06-25 | 伊莱克斯公司 | Vacuum cleaner |
| CN106572773A (en) * | 2014-08-11 | 2017-04-19 | 三星电子株式会社 | Vacuum cleaner |
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Also Published As
| Publication number | Publication date |
|---|---|
| CN111441969A (en) | 2020-07-24 |
| JP2020112145A (en) | 2020-07-27 |
| TWI723518B (en) | 2021-04-01 |
| TW202028616A (en) | 2020-08-01 |
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