JP2023067008A - impeller and vacuum cleaner using the same - Google Patents

Abstract

To provide a small impeller suitable for a stick type vacuum cleaner.SOLUTION: An impeller 20 is rotationally driven in a constant rotational direction. The impeller comprises a boss part 21 fixed to a shaft 13a of an electric motor, a base part 22 connected to the boss part, and a plurality of blades 23 arranged on the base part 22. The impeller is configured such that air passes between the blades 23 in a radial direction or in a direction inclined with respect to a rotational axis A during rotation, to generate a suction force on the upstream side of an air channel. Each of the blades 23 has a swept wing shape, and a tip 23d side of a wind cutting edge part 23a is located higher than a base end 23c side thereof.SELECTED DRAWING: Figure 3

Description

The disclosed technology relates to an impeller and a vacuum cleaner using the impeller.

In recent years, many compact and lightweight stick-type vacuum cleaners in which the vacuum cleaner body, hose, electric cord, etc. are omitted have been put on the market. This kind of vacuum cleaner is popular because it is cordless and easy to handle.

A stick-type vacuum cleaner is equipped with a small impeller with a diameter of about 3 to 5 cm. In order to generate a high suction force with such a small impeller, the motor that rotates the impeller is also small and lightweight, and can rotate at a high speed of 50000 r/min or more while securing a certain amount of torque. .

Conventional examples of small impellers used in vacuum cleaners of this type are disclosed in Patent Document 1 and Patent Document 2.

Japanese Patent No. 3724413 JP 2017-82759 A

In the future, it is expected that motors will rotate at higher speeds in order to achieve even higher suction forces. Accordingly, impellers are also required to have higher performance.

On the other hand, when the present inventors examined it, they found that the impellers of Patent Document 1 and Patent Document 2 have room for improvement.

An object of the technology disclosed is to provide a small impeller suitable for a stick-type vacuum cleaner and capable of improving suction power.

The disclosed technology relates to an impeller that is arranged in a predetermined air passage and that is rotationally driven by an electric motor in a constant rotational direction.

The impeller includes a boss portion fixed with its rotation axis aligned with the shaft of the electric motor, a base portion connected to the boss portion and increasing in diameter from the suction side to the discharge side of the air passage, and a plurality of blades radially arranged on the base.

Air passes between the blades in a radial direction or in a direction inclined with respect to the axis of rotation during rotation, thereby generating a suction force on the upstream side of the air passage.

Then, each of the blades has a wind cutting edge formed by a center side edge formed to extend in the radial direction, and the tip end side of the wind cutting edge is further from the base end side of the wind cutting edge than the base end side of the wind cut edge. It has a swept-back wing shape positioned on the rear side of the direction, and the tip side of the wind cutting edge is positioned closer to the suction side of the air passage than the base end side of the wind cutting edge.

By shaping each blade in this way on the suction side of the impeller, the suction power can be improved. That is, by forming each blade into a swept wing shape, it is advantageous for high rotation, and efficiency can be improved. By inclining the tip side of the wind cutting edge toward the suction side, the load on the blade surface can be reduced. By combining these shapes, the suction efficiency can be increased and the suction force can be improved.

In the impeller, the receding angle of the wind cutting edge is set to 15° or more and 19° or less, and the inclination angle of the wind cutting edge toward the suction side of the air passage is set to 18° or more and 26° or less. preferable.

The inventors of the present invention conducted fluid analysis and conducted various studies on the configuration of the blade, and found that the suction efficiency can be optimized by adopting such settings. Therefore, by designing each blade of the impeller in this way, it becomes possible to improve the suction power over the conventional impeller.

The impeller described above is preferably applied to vacuum cleaners, especially stick-type vacuum cleaners. That is, a vacuum cleaner having the impeller described above and an electric motor that can be driven by power supply from a battery may be configured.

With this impeller, a high suction force can be obtained in spite of its extremely small size.

According to the impeller to which the disclosed technology is applied, the suction force can be improved more than the conventional impeller. By using this impeller in a stick-type vacuum cleaner, a high-performance vacuum cleaner can be realized.

1 is a schematic diagram showing a main part of a stick-type vacuum cleaner of an embodiment; FIG. FIG. 2 is a schematic diagram showing the internal structure of the portion indicated by the encircling line L1 in FIG. 1; It is a figure for demonstrating the structure of an impeller. It is the perspective view of an impeller, and its schematic sectional drawing. It is a figure for demonstrating the structure of an impeller. It is the figure which looked at the impeller from the suction side. It is a schematic diagram showing a model of fluid analysis. 4 is a graph summarizing the results of fluid analysis; FIG. 10 is a diagram showing an example of a fluid analysis result for each sweepback angle; 4 is a graph summarizing the results of fluid analysis; It is a figure equivalent to Drawing 2 showing a modification.

Embodiments of the disclosed technology will be described in detail below with reference to the drawings. However, the following description is essentially merely an example, and does not limit the present invention, its applications, or its uses.

<vacuum cleaner>
FIG. 1 shows an example of a main part of a stick-type vacuum cleaner (hereinafter simply referred to as a vacuum cleaner 1) suitable for the technology disclosed. This vacuum cleaner 1 is of a cordless type.

This vacuum cleaner 1 is equipped with an impeller 20 to which the technology disclosed is applied. A vacuum cleaner 1 is composed of a tube portion 2, a body portion 3, a dust case 4, a handle portion 5, and the like.

The tube portion 2 is made of an elongated cylindrical member. Although not shown, a head of a vacuum cleaner 1 for sucking dust is attached to the tip of the tube portion 2 .

The body portion 3 and the handle portion 5 are provided integrally with the base end portion of the tube portion 2 . The body portion 3 accommodates a suction unit 10 to be described later. Although not shown, the handle portion 5 accommodates a battery, a control portion, and the like. The controller controls driving of the suction unit 10 . The battery is a rechargeable secondary battery that powers the suction unit 10 .

The grip portion 5 is a portion that is gripped by the user. The vacuum cleaner 1 is configured so that the user can handle it while holding the handle portion 5 with one hand.

A dust case 4 is installed below the body portion 3 . The dust case 4 is configured to be detachable from the body portion 3 . When the suction unit 10 is driven, a strong suction force is generated in the head. As a result, dust sucked from the head passes through the tube portion 2 and is collected in the dust case 4 .

(Inside the main body)
FIG. 2 shows the internal structure of the main body 3 (the portion indicated by the encircling line L1 in FIG. 1). Note that both the cross-sectional shape and the outer shape of the diffuser 15, which will be described later, are shown to the left and right in FIG.

An exhaust chamber 30, a filtration chamber 31, and the like are provided inside the body portion 3. As shown in FIG. The exhaust chamber 30 is a cylindrical space with one end sealed, and has a plurality of inner exhaust holes 30a formed on its outer peripheral surface. The filtration chamber 31 is provided so as to surround the exhaust chamber 30 . A cylindrical filter 32 for trapping dust is attached to the entire circumference of the filtering chamber 31 .

A plurality of outer exhaust holes 33 are formed in the cover of the main body 3 that defines the outer peripheral side of the filtration chamber 31, as also shown in FIG. The suction unit 10 is accommodated inside the main body 3 with a part of the suction unit 10 entering the exhaust chamber 30 .

The suction unit 10 includes an upstream shroud 11, a downstream shroud 12, a fan motor 13 (electric motor), an impeller 20, a diffuser 15, and the like. The upstream shroud 11 and the downstream shroud 12 form a channel (airway 50) through which air flows.

The upstream shroud 11 is made of a cylindrical member and has a first large-diameter portion 11a with a large diameter and a first reduced-diameter portion 11b narrowed from the first large-diameter portion 11a. The downstream shroud 12 is also made of a cylindrical member and has a second large-diameter portion 12a having a large diameter and a second reduced-diameter portion 12b narrowed from the second large-diameter portion 12a.

The first reduced diameter portion 11 b of the upstream shroud 11 is connected to the second reduced diameter portion 12 b of the downstream shroud 12 . The upstream shroud 11 and the downstream shroud 12 are integrated with their centers aligned. The first large diameter portion 11a is connected to the dust case 4, and the upstream shroud 11 and the dust case 4 communicate with each other. The downstream shroud 12 is arranged inside the exhaust chamber 30 .

The fan motor 13 is accommodated in the upstream shroud 11 with its shaft 13a directed toward the downstream shroud 12 and the center of the upstream shroud 11 and the rotation axis A aligned.

Fan motor 13 is very small. For example, the fan motor 13 shown in the figure has an outer diameter of approximately 70 mm and a total height of approximately 40 mm (so-called palm size). Therefore, its weight is also extremely light.

However, the fan motor 13 is configured so as to obtain high efficiency and high output so as to obtain sufficient performance as the cleaner 1 by using the electric power of the battery. For example, in the case of the fan motor 13 shown in the figure, it can be driven at a high speed of 50,000 r/min or more, or even at an ultra-high speed of 100,000 r/min or more, with a power consumption of 600 W, and a suction power of 250 W or more can be obtained. It is configured.

The impeller 20 is housed in the second diameter-reduced portion 12 b that forms the air passage 50 . The impeller 20 includes a boss portion 21 fixed with the rotation axis A aligned with the shaft 13a of the fan motor 13; and a plurality of blades 23. In the technology disclosed, the structure of the impeller 20 is particularly devised. Details of the impeller 20 will be described separately later.

The diffuser 15 is accommodated in the second large diameter portion 12a. The illustrated diffuser 15 is composed of an upper diffuser 15U and a lower diffuser 15D. One diffuser 15 may be provided depending on the specifications of the suction unit 10 .

Each of the upper diffuser 15U and the lower diffuser 15D is formed of a cylindrical member, and formed with a plurality of vanes 15a extending obliquely with respect to the axial direction on the outer peripheral surface thereof. The inclination angle of the vanes 15a of the lower diffuser 15D is smaller than that of the upper diffuser 15U. Each of the upper diffuser 15U and the lower diffuser 15D is fixed to the inner peripheral surface of the second large diameter portion 12a.

While the cleaner 1 is running, the fan motor 13 is rotationally driven by the fan motor 13, so that the impeller 20 rotates in a constant rotational direction at high speed. As a result, air flows from the dust case 4 into the upstream shroud 11 as indicated by an arrow Y1, and a suction force is generated upstream of the second diameter-reduced portion 12b. The air that has flowed into the upstream shroud 11 passes through the first large diameter portion 11a and the first reduced diameter portion 11b while cooling the fan motor 13, and is sucked into the second reduced diameter portion 12b.

The air that has flowed into the second diameter-reduced portion 12b from its suction side 50a passes through the space between the inner wall surface of the second diameter-reduced portion 12b and the base portion 22 of the impeller 20 (more specifically, between the blades 23). is discharged from the second reduced diameter portion 12b and flows into the second large diameter portion 12a. The air that has flowed into the second large diameter portion 12a from the discharge side 50b of the second reduced diameter portion 12b enters the space (details and between the vanes 15a) and flows into the exhaust chamber 30.

By passing through the upper end diffuser 15 and the lower stage diffuser 15D, the air flows into the exhaust chamber 30 while being rectified in the axial direction as indicated by the arrow Y2. The air that has flowed into the exhaust chamber 30 flows through the inner exhaust hole 30a into the filter chamber 31, passes through the filter 32, and is then exhausted out of the main body 3 through the outer exhaust hole 33 as indicated by arrow Y3.

<Impeller>
The impeller 20 is shown in FIGS. As described above, impeller 20 includes boss portion 21 , base portion 22 and a plurality of blades 23 . For convenience, as shown in FIG. 3, the tip side of the boss portion 21 (the suction side 50a of the air passage 50) is referred to as the upper side in the description.

Specifically, the impeller 20 includes a boss portion 21 fixed with the rotation axis A aligned with the shaft 13a, and a boss portion 21 connected to the boss portion 21 and extending from the suction side 50a of the air passage 50 toward the discharge side 50b. It has an annular base portion 22 with a larger diameter and a plurality of blades 23 radially arranged on the upper surface of the base portion 22 . The impeller 20 is a resin molded product and is integrally formed.

The impeller 20 is driven by the fan motor 13 to rotate counterclockwise when viewed from above, as indicated by an arrow Yr in FIGS. 3 and 4 . The impeller 20 is inclined so that the outer peripheral side of each blade 23 is positioned rearward in the rotation direction from the center side, and air is inclined with respect to the rotation axis A between the blades 23 during rotation. It is configured to pass through in the direction indicated. That is, this impeller 20 corresponds to a mixed flow fan.

The boss portion 21 is formed of a cylindrical portion, and the shaft 13a is fixed to the central portion thereof. The base portion 22 is formed of a conical portion that continues to the upper portion of the boss portion 21, and the upper surface of the base portion 22 is gently curved upward toward the outer peripheral side. The degree of inclination is approximately 30°, and the inclination ranges from approximately 20° to 40°.

Each blade 23 consists of a thin plate-like portion and is provided so as to rise upward from the upper surface of the base. This impeller 20 has nine blades 23, and these blades 23 are arranged at regular intervals in the circumferential direction. Each blade 23 has a strip-like appearance with a long edge on one side and a very short edge on the other side. The longer edge (winding edge 23 a ) is located on the center side of the base portion 22 , and the shorter edge (winding edge 23 b ) is located on the outer peripheral side of the base portion 22 .

Each of the baffle edge 23a and the baffle edge 23b extends linearly. Each blade 23 has a twisted shape from a wind cutting edge 23a toward a wind sending edge 23b. The tip end side of the wind cutting edge portion 23a is twisted and slanted in the rotational advancing direction, and the tip end side of the wind blowing edge portion 23b is twisted and slanted in the reverse rotation direction. As shown in FIG. 4, the windshield edge 23a is formed to extend radially when viewed from the axial direction. As a result, the protruding side edge of each blade 23 is configured to follow the inner peripheral surface of the second diameter-reduced portion 12b with a slight gap therebetween.

In the case of this impeller 20, each blade 23 is configured so that the tip 23d side of the wind cutting edge 23a is positioned rearward in the rotational direction from the base end 23c side of the wind cutting edge 23a. , this shape is called a swept wing shape). The swept wing shape reduces the air resistance of the blade 23, which is advantageous for high rotation.

When the present inventors examined the swept-back angle θ2 of the swept-back blade shape (the angle at which the wind cutting edge 23a recedes with respect to the reference line extending in the radial direction, see FIG. 4) by fluid analysis, it was found that the swept-back It was found that the suction performance can be improved by selecting the angle θ2 (details will be described later).

(Inclination angle of wind cutting edge)
Furthermore, in the case of this impeller 20, the tip 23d side of the wind cutting edge 23a is positioned above the base end 23c side of the wind cutting edge 23a (suction side 50a of the air passage 50). Specifically, as schematically shown in FIG. 3, the wind cutting edge 23a of each blade 23 is inclined upward from the base end 23c connected to the boss 21 toward the tip end 23d.

By forming the wind cutting edge 23a of each blade 23 in such a shape, the blade load on the end portion of each blade 23 located on the air inflow side can be reduced, and the leakage flow can be reduced. Then, the present inventors examined the inclination angle θ1 of the windshield edge 23a (the angle at which the windshield edge 23a is inclined with respect to the reference line orthogonal to the rotation axis A, see FIG. 3) by fluid analysis. However, it has been found that the suction performance can be improved by selecting the inclination angle .theta.1 as well as the receding angle .theta.2.

Specifically, as shown in FIG. 5, a model of the air passage 50 (the second reduced diameter portion 12b) in which the impeller 20 is housed is set by fluid analysis, and as indicated by the arrow in FIG. It was investigated how the suction efficiency (suction force/motor output) changes by changing the magnitude of the inclination angle θ1 toward the suction side 50a of the passage 50. FIG.

FIG. 6 shows the test results. The vertical axis is the suction efficiency, and the horizontal axis is the tilt angle θ1. As the tilt angle θ1 increased, the suction efficiency increased and then decreased, and a peak was observed around the tilt angle θ1 of about 22°. Specifically, it has been found that the suction efficiency can be optimized by setting the inclination angle θ1 of the wind cutting edge 23a to 18° or more and 26° or less.

Therefore, the inclination angle θ1 of the wind cutting edge 23a of the impeller 20 is set to 18° or more and 26° or less, and is optimized so as to improve the suction force. The peak inclination angle θ1 is most preferable, but if the inclination angle θ1 is selected within this range according to the specifications of the impeller 20, the same effect can be obtained.

(retraction angle of wind edge)
Similarly to the fluid analysis of the inclination angle θ1, a model as shown in FIG. 5 is set for the sweepback angle θ2 of the wind edge 23a, and how the suction efficiency changes by changing the magnitude of the sweepback angle θ2. I investigated whether An example of the analysis result is shown in FIG.

Each figure in FIG. 7 shows the flow analysis results of the air flowing through the second reduced diameter portion 12b (specifically, between the blades 23) at three different sweepback angles θ2. The upper diagram (a) has a sweepback angle θ2 of 27°, the middle diagram (b) has a sweepback angle θ2 of 17°, and the lower diagram (c) has a sweepback angle θ2 of 7°. The high concentration portion R1 has a large amount of air flow, and the low concentration portion R2 has a small air flow amount.

In the upper diagram (a) where the receding angle θ2 is large, the air flowing between the blades 23 tends to flow toward the base portion 22 on the downstream side. On the other hand, in the lower diagram (c) where the receding angle θ2 is small, the air flowing between the blades 23 tends to flow toward the inner wall surface of the second diameter-reduced portion 12b. In the middle diagram (b) in which the sweepback angle θ2 is intermediate between these, the air flowing between the blades 23 tends to flow through the intermediate portions between the blades 23 without bias.

If the air flows biased toward the base portion 22 side, the discharge flow becomes uneven and separation occurs near the base portion 22 on the discharge side 50b, thereby increasing the mixing loss in the impeller 20. FIG. This causes a reduction in suction power. When the air flows biased toward the inner wall surface of the second diameter-reduced portion 12b, there is a gap between each blade 23 and the inner wall surface of the second diameter-reduced portion 12b. and reduce the suction power. On the other hand, when the air flows through the intermediate portions between the blades 23 without bias, the rotational force of the impeller 20 can be effectively applied to the air, and the suction force can be efficiently generated.

FIG. 8 shows the result of summarizing the relationship between the magnitude of the receding angle θ2 and the suction efficiency. As the sweepback angle θ2 increased, the suction efficiency increased and then decreased, and a peak was observed around the sweepback angle θ2 of about 17°. Specifically, it was found that the suction efficiency can be optimized by setting the receding angle θ2 of the wind cutting edge 23a to 15° or more and 19° or less.

Therefore, the receding angle θ2 of the wind cutting edge 23a of the impeller 20 is set to 15° or more and 19° or less, and is optimized so as to improve the suction force. The peak sweepback angle θ2 is most preferable, but if the sweepback angle θ2 is selected within this range according to the specifications of the impeller 20, an effect equivalent to that can be obtained.

In the case of this impeller 20, both the inclination angle .theta.1 and the swept angle .theta.2 of the wind edge 23a are optimized. Therefore, by combining these two effects, the suction force can be further improved.

That is, according to the impeller 20, the performance of the motor, which rotates at a higher speed, can be further enhanced, and a high suction force can be generated. Therefore, by combining the fan motor 13 rotating at high speed and the impeller 20, the vacuum cleaner 1 with high performance can be realized.

Note that the technology disclosed is not limited to the above-described embodiments, and includes various other configurations. For example, in the above-described embodiment, the impeller 20 corresponding to a mixed flow fan was illustrated, but it may correspond to a centrifugal fan in which air passes radially between the blades 23 during rotation.

Further, in the above-described embodiment, the fan motor 13 is arranged on the upstream side with respect to the impeller 20, but as shown in FIG. A fan motor 13 may be arranged at 30 .

In the above-described embodiment, the impeller 20 rotating counterclockwise was exemplified, but depending on the specifications, the direction of each blade 23 may be reversed to rotate clockwise.

Reference Signs List 1 vacuum cleaner 2 pipe portion 3 body portion 4 dust case 5 handle portion 10 suction unit 11 upstream shroud 12 downstream shroud 13 fan motor (electric motor)
15 Diffuser 20 Impeller 21 Boss 22 Base 23 Blade 23a Wind cutting edge 23b Winding edge 23c Base end 23d Tip 30 Exhaust chamber 30a Inside exhaust hole 31 Filtration chamber 32 Filter 33 Outside exhaust hole 50 Air passage 50a Suction side 50b Discharge Side A rotation axis

Claims (3)

An impeller arranged in a predetermined air passage and driven to rotate by an electric motor in a constant rotation direction,
a boss portion fixed in a state where the rotation axis is aligned with the shaft of the electric motor;
a base portion connected to the boss portion and having a diameter that increases from the suction side toward the discharge side of the air passage;
a plurality of blades radially arranged on the base;
with
At the time of rotation, air passes between the blades in a radial direction or in a direction inclined with respect to the rotation axis, thereby generating a suction force on the upstream side of the air passage,
Each of the blades has a wind cutting edge formed by a center side edge formed to extend in the radial direction, and the tip side of the wind cutting edge is positioned further in the rotational direction than the base end side of the wind cutting edge. An impeller having a swept back blade shape located on the rear side, and having a tip end side of the wind cutting edge portion positioned closer to the suction side of the air passage than a base end side of the wind cutting edge portion. The impeller according to claim 1,
The impeller, wherein the receding angle of the wind cutting edge is 15° or more and 19° or less, and the inclination angle of the wind cutting edge toward the suction side of the air passage is set to 18° or more and 26° or less. being a vacuum cleaner
A vacuum cleaner comprising the impeller according to claim 1 or 2 and the electric motor drivable by power supply from a battery.

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