WO2021090562A1

WO2021090562A1 - Mobile air purifier

Info

Publication number: WO2021090562A1
Application number: PCT/JP2020/032635
Authority: WO
Inventors: 浩平京谷; 梓網野; 大平　昭義; 健太郎佐野; 佐知田中
Original assignee: 株式会社日立製作所
Priority date: 2019-11-06
Filing date: 2020-08-28
Publication date: 2021-05-14
Also published as: JP7384637B2; JP2021076268A

Abstract

Achieved is a mobile air purifier capable of suitably capturing both particles suspended in the air and particles accumulated on the floor. To this end, a mobile air purifier (1) comprises: a housing (2); a filter (3) that is provided in the housing (2) and that filters air which passes through the filter; an impeller (6) that is provided in the housing (2) and that causes air to pass through the filter (3), an upper end surface (6h2) of said impeller being installed in a higher position than an upper end surface (3a) of the filter (3); a first motor (6m) that is provided in the housing (2) and that drives the impeller (6); a bottom surface plate (2t) that is provided to the bottom section of the housing (2) and that has formed therein an intake port (2i) for sucking in air; a plurality of wheels that are mounted on the housing (2) and that separate the bottom surface plate (2t) from an installation surface Y; and a brush (10b) that protrudes downward from the bottom surface plate (2t) so as to make contact with the installation surface Y.

Description

Mobile air purifier

The present invention relates to a mobile air purifier.

As an example of the autonomous traveling type air purifier, in paragraph [0007] of Patent Document 1 below, "... in the self-propelled air purifier, an intake port is provided in the center of the upper surface of the housing, and the side surface or the side surface or Since the exhaust ports are provided on the outer edge and the side surface of the upper surface, the flow of clean air exhausted from the self-propelled air purifier contains a horizontal component. As a result, the middle layer space of the room, Air purification (replacement with clean air) in a so-called living space can be performed quickly. Further, since the first filter member and the second filter member are provided, the air can be purified more reliably. Since the first filter member and the second filter member are rotated by the motor, both quietness and high dust collection can be achieved at the same time. Further, the fan, the first filter member and the second filter member can be easily made. It is possible to achieve miniaturization of the self-propelled air purifier. "
Further, as an example of the self-propelled vacuum cleaner, in paragraphs [0011] and [0012] of Patent Document 2, "the effect of the invention" is described as "the support structure of the rotary shaft for the auxiliary brush of the present invention is the rotation of the rotary shaft. At times, the rotating shaft and the housing are configured so that the first sliding contact surface of the rotating shaft and the second sliding contact surface of the slide bearing can be pressure-contacted in the axial direction of the rotating shaft and sliding-contacted in the rotational direction. As a result, according to the present invention, for an auxiliary brush that can reduce wear and rattling of the rotation shaft and rotation shaft of the side brush and the bottom of the housing. A support structure for a rotating shaft and a self-propelled vacuum cleaner equipped with the support structure can be provided. "

International Publication No. 2018/074052 JP-A-2018-473557

By the way, some fine particles such as pollen and house dust existing in the living space continue to float for a long time and some are deposited on the floor surface in a relatively short time. And even if the fine particles are once deposited on the floor surface, there is a concern that they will fly up again due to human activities and will be sucked by humans. Therefore, when purifying these fine particles, it is considered preferable to collect both those floating in the air and those deposited on the floor surface. However, the self-propelled air purifier described in Patent Document 1 has a low function of collecting fine particles deposited on the floor surface. Further, the self-propelled vacuum cleaner described in Patent Document 2 has a low function of collecting fine particles suspended in the air.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mobile air purifier capable of appropriately collecting both fine particles suspended in air and fine particles deposited on a floor surface.

In order to solve the above problems, the mobile air purifier of the present invention includes a housing, a filter provided in the housing for filtering the passing air, and a filter provided in the housing for passing air through the filter. An impeller whose upper end surface is installed at a position higher than the upper end surface of the filter, a first motor provided in the housing to drive the impeller, and an impeller provided at the bottom of the housing to allow air to flow. A bottom plate having a suction port formed therein, a plurality of wheels mounted on the housing and separating the bottom plate from the installation surface, and a brush protruding downward from the bottom plate so as to come into contact with the installation surface. It is characterized by having.

According to the present invention, both fine particles suspended in the air and fine particles deposited on the floor surface can be appropriately collected.

It is a perspective view of the mobile air purifier by a preferable 1st Embodiment. It is a top view of the mobile air purifier. It is a bottom view of a mobile air purifier. FIG. 2 is a sectional view taken along line IV-IV of FIG. It is a figure which shows the numerical simulation result of the flow field in a mobile air purifier. It is a figure which shows the numerical simulation result of another flow field in a mobile air purifier. It is a figure which shows the relationship between a speed ratio and an area ratio. It is a bottom view of the mobile air purifier according to a preferred second embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate. The following description shows specific examples of the contents of the present invention, and the present invention is not limited to these descriptions. Various changes and modifications can be made by those skilled in the art within the scope of the technical ideas disclosed in the present specification, and it is planned from the beginning that the following configurations are appropriately combined. Further, in all the drawings for explaining the present invention, those having the same function may be designated by the same reference numerals, and the repeated description thereof may be omitted. Then, as shown in FIG. 1 and the like, front and back, top and bottom, and left and right are defined.

[First Embodiment]
<Structure of the first embodiment>
(overall structure)
FIG. 1 is a perspective view of the mobile air purifier 1 according to the preferred first embodiment.
The mobile air purifier 1 includes a main body 1H formed in a flat substantially columnar shape and a traveling mechanism 1r for running the main body 1H. The traveling mechanism 1r includes the side wheels 9s1. The main body 1H includes an outer cover 2 (housing) that covers the upper surface and the side surface, and a plurality of main body discharge ports 2o are formed on the upper surface of the outer cover 2.

Further, the main body 1H includes a sensor unit 22, a control unit 24, and a storage battery 26. The sensor unit 22 is arranged at the front portion of the main body 1H. The sensor unit 22 may include a dust sensor that detects dust, an odor sensor that detects odors, an infrared sensor that detects obstacles, and / or a TOF (Time of Flight) sensor that measures the distance to obstacles. ..

Further, the storage battery 26 is a power source for each part of the mobile air purifier 1, and is arranged inside the main body 1H. The control unit 24 is also arranged inside the main body 1H. Power is supplied to the control unit 24 from the storage battery 26. As a result, the control unit 24 controls each unit of the mobile air purifier 1 based on the information from the sensor unit 22. That is, the control unit 24 selects one of three operation modes of "weak", "standard", and "strong" for the mobile air purifier 1 based on the information from the sensor unit 22. To do. As described above, by having a plurality of operation modes, the mobile air purifier 1 can automatically select an operation mode suitable for the degree of contamination of the air or the floor surface. However, the operation mode may be manually specified by the user.

FIG. 2 is a plan view of the mobile air purifier 1. The upper surface of the exterior cover 2 is formed in a substantially disk shape. The main body discharge port 2o described above has a shape in which an oval is curved in an arc shape, and is formed at eight positions equally divided in the circumferential direction along the outer circumference of the upper surface of the exterior cover 2.

FIG. 3 is a bottom view of the mobile air purifier 1.
As shown in FIG. 3, the bottom surface of the main body 1H is covered with a substantially disk-shaped bottom cover 2t (bottom plate). The bottom surface shape of the exterior cover 2 has a shape that is slightly wider in the left-right direction than the circular shape. Inside the portion of the exterior cover 2 that slightly spreads in the left-right direction, a pair of left and right side wheels 9s1, 9s2 (wheels), a pair of left and right wheel motors 9m1, 9m2 (second motor), and a pulley 9p1, 9p2 and are stored. These are included in the traveling mechanism 1r. The rotational force of the wheel motors 9m1 and 9m2 is transmitted to the side wheels 9s1 and 9s2 via a belt (not shown) as a power transmission mechanism and pulleys 9p1 and 9p2. As a result, the wheel motors 9m1 and 9m2 rotate and drive the side wheels 9s1 and 9s2, respectively.

The brush 10b is formed in a substantially rectangular plate shape, and the central portion of the brush 10b is rotatably supported at the center point O of the bottom cover 2t. When the brush 10b is rotationally driven, the brush 10b slides on the floor surface and winds up the fine particles accumulated on the floor surface. The brush 10b is included in the floor cleaning mechanism 1z. The width of the brush 10b is called the brush diameter Db (brush width). The brush 10b is rotationally driven in the direction of arrow β so that the tip speed becomes Vb. The front wheel 9k is attached to the bottom cover 2t via the caster 9c slightly in front of the rotation range of the brush 10b. The caster 9c is rotatably supported by the bottom cover 2t. Here, the side wheels 9s1 and 9s2 become driving wheels, and the front wheels 9k become driven wheels. The front wheels 9k and casters 9c are also included in the traveling mechanism 1r.

Further, in the front and rear parts of the bottom cover 2t, a total of 4 main body suction ports 2i (suction ports), which are through holes having an elliptical shape curved in an arc shape, are provided along the outer circumference of the bottom cover 2t. It is formed at several locations. Here, as shown in the figure, the distance from the center point O to the shortest point Pm in the opening region of the main body suction port 2i is referred to as a suction port inner diameter Rm. Further, the distance from the center point O to the farthest point Pn in the opening region of the main body suction port 2i is referred to as a suction port outer diameter Rn.

The brush diameter Db is preferably shorter than twice the suction port outer diameter Rn. This makes it easier to collect the dust rolled up by the brush 10b from the main body suction port 2i, so that the amount of dust scattered in the room can be suppressed. Further, as shown in the illustrated example, it is more preferable that the brush diameter Db is shorter than twice the suction port inner diameter Rm. This is because the dust wound up by the brush 10b can be more easily collected from the main body suction port 2i. Further, in the area occupied by the side wheels 9s1 and 9s2, the distance from the center point O to the shortest position Pw is called the wheel distance Rw. The wheel distance Rw is also preferably shorter than the suction port outer diameter Rn. This makes it easier to collect the dust rolled up by the side wheels 9s1 and 9s2 from the main body suction port 2i, so that the amount of dust scattered in the room can be suppressed.

FIG. 4 is a sectional view taken along line IV-IV of FIG. As shown in FIG. 4, the mobile air purifier 1 cleans the blower mechanism 1w that blows air from the lower side to the upper side of the main body 1H, the traveling mechanism 1r that runs the main body 1H, and the floor surface Y (installation surface). It includes a floor cleaning mechanism 1z, a filter 3, an exterior cover 2 containing these, and a bottom cover 2t. That is, the main body 1H is covered with an exterior cover 2 which is a flat and substantially columnar housing, and a bottom cover 2t.

As shown in the figure, the bottom cover 2t is located above the floor surface Y by a distance L. Therefore, the main body suction port 2i (see FIG. 3) is also separated from the floor surface by the separation distance L. The air near the floor surface Y on the entire circumference of the main body 1H flows into the inside of the main body 1H along the arrows α1 and α7 through the main body suction port 2i (see FIG. 3). Dust and the like contained in the inflowing air are removed by the filter 3. Then, the purified air is discharged to the outside from the main body discharge port 2o (see FIG. 2) along the arrow α2.

The blower mechanism 1w includes a centrifugal impeller 6 (impeller), an impeller motor 6m (first motor), and a winged diffuser 7. The impeller motor 6m is coaxially arranged with the centrifugal impeller 6 and rotationally drives the centrifugal impeller 6. The centrifugal impeller 6 includes a plurality of blades 6h, and the upper end surface 6h2 of these blades 6h is a substantially flat surface. Further, as shown in the drawing, the side wheel 9s1 projects downward from the bottom cover 2t and comes into contact with the floor surface Y. The other side wheel 9s2 (see FIG. 3) is also arranged so as to be symmetrical with respect to the side wheel 9s1.

The filter 3 shown in FIG. 4 is formed in a substantially cylindrical shape and is arranged inside the main body suction port 2i (see FIG. 3). Although the structure of the filter 3 is not shown, the filter 3 is a pre-filter for removing dust having a large particle size and a HEPA filter for removing dust having a small particle size from the outer circumference to the inner circumference. And a deodorizing filter for removing odorous components.

In FIG. 4, the meanings of the suction port outer diameter Rn and the suction port inner diameter Rm are as described in FIG. In the present embodiment, the radius R3 of the outer peripheral surface of the filter 3 is shorter than the suction port outer diameter Rn. This facilitates the formation of an air flow from the outer peripheral surface to the inner peripheral surface of the filter 3. Further, as shown in FIG. 4, when the radius R3 is shorter than the suction port inner diameter Rm, it becomes easier to form an air flow from the outer peripheral surface to the inner peripheral surface of the filter 3, which is more preferable.

The brush motor 10m (third motor) has a vertical (more specifically, orthogonal to the floor surface Y) rotation axis M, and rotationally drives the brush 10b. The control unit 24 (see FIG. 1) has an impeller motor 6 m, a wheel motor 9 m 1, 9 m 2 (see FIG. 3), a brush motor 10 m, etc., based on various sensor information from the sensor unit 22 (see FIG. 1). To control. As a result, the mobile air purifier 1 purifies the air in the room by passing through the filter 3 while autonomously traveling.

(Details of air flow)
Next, the details of the air flow in the present embodiment will be described with reference to FIG.
As shown by the arrow α3 in FIG. 4, when the impeller motor 6m is rotationally driven, the centrifugal impeller 6 connected to the motor 6m rotates. Due to the rotation of the centrifugal impeller 6, indoor air is sucked into the main body 1H from the main body suction port 2i (see FIG. 3) as shown by arrows α1 and α7. The air flowing in from the main body suction port 2i passes through the filter 3 from the outer peripheral surface to the inner peripheral surface along the arrow α4 in FIG. As a result, dust, odor, and the like are removed from the air, and the air is purified. The purified air is deflected upward from the inner peripheral surface of the filter 3 at a substantially right angle and reaches the suction port 6i of the centrifugal impeller 6.

In the centrifugal impeller 6, the air that was heading upward is deflected at a substantially right angle so as to face sideways, as shown by the arrow α5. The air flowing to the side reaches the winged diffuser 7 provided on the outer circumference of the centrifugal impeller 6. As shown by the arrow α6 in FIG. 4, the air reaching the winged diffuser 7 is decelerated and boosted inside the winged diffuser 7 from the main body discharge port 2o (see FIG. 2) along the arrow α2. It is released to the outside (indoor).

(Arrangement of filter 3 and centrifugal impeller 6)
As shown in FIG. 4, in the present embodiment, the filter 3 is arranged closer to the side than the center of the main body 1H. As a result, the air flowing in from the outer periphery of the filter 3 (arrows α1 and α7 in FIG. 4) is deflected at a substantially right angle and flows into the suction port 6i of the centrifugal impeller 6. In other words, the air that has passed through the filter 3 from the outer peripheral surface to the inner peripheral surface is deflected at a substantially right angle and flows into the suction port 6i of the centrifugal impeller 6. Since the filter 3 is arranged below the centrifugal impeller 6, the fine particles sucked from the main body suction port 2i (see FIG. 3) are collected by the filter 3 immediately after the suction, so that the inside of the main body 1H is collected. It is possible to suppress the accumulation of dust on the surface.

Further, the height of the suction port 6i of the centrifugal impeller 6 from the floor surface Y is substantially the same as the upper end surface 3a of the filter 3. With this configuration, it is possible to reduce the energy loss when the air that has passed through the filter 3 flows into the main body suction port 2i.

(Collecting suspended particles)
Next, the collection of fine particles suspended in the air will be described.
In FIG. 4, the main body suction port 2i is opened facing the floor surface Y, but since the bottom cover 2t is separated from the floor surface Y by the separation distance L, the outer cover 2 is along the arrow α7 from the periphery. It is possible to inhale air and collect fine particles suspended in the air. Further, by providing the main body suction port 2i away from the floor surface Y, it is possible to reduce the pressure loss of the flow from the periphery of the exterior cover 2 to the main body suction port 2i. As a result, the amount of air sucked by the main body 1H becomes large, and the air in the room can be quickly cleaned. The separation distance L between the main body suction port 2i and the floor surface Y is, for example, 20 mm. Further, in the space below the exterior cover 2, a band-shaped region having a width of a separation distance L along the bottom edge portion of the exterior cover 2 is referred to as a “bottom boundary D”.

(Collecting accumulated fine particles)
Next, the collection of fine particles deposited on the floor surface Y will be described.
In FIG. 4, the brush 10b is rotationally driven by the brush motor 10m in the direction of the arrow β in FIG. 3 about the vertical direction (more specifically, the direction orthogonal to the floor surface Y) to reach the floor surface Y. Roll up the accumulated fine particles. The fine particles wound up by the brush 10b are taken into the main body 1H together with air and cleaned along the arrow α1 in FIG.

5 and 6 are numerical simulation results showing the flow field in the VV cross section of FIG. In these figures, the direction of the arrow corresponds to the direction of air flow and the length of the arrow corresponds to the wind speed.
FIG. 5 shows an example in which the flow direction is inward in the radial direction on the entire circumference of the bottom boundary D. On the other hand, FIG. 6 shows a case where the flow direction is outward in the radial direction in a part region G of the bottom boundary D. Here, the product of the "bottom boundary length Dm (length of the bottom boundary D)" and the "distance distance L between the main body suction port 2i and the floor surface Y" is referred to as the bottom boundary area A. That is, the bottom boundary area A is represented by the following equation (1).
A = Dm × L ... Equation (1)
In the formula (1), the unit of the bottom surface boundary area A is, for example, [m ² ], and the unit of the bottom surface boundary length Dm and the separation distance L is, for example, [m].

In FIGS. 5 and 6, the air volume of the air flowing from the bottom boundary D below the exterior cover 2, in other words, the air volume of the centrifugal impeller 6 is referred to as the air volume Q. When the air volume Q is relatively large and the tip velocity Vb (FIG. 3) of the brush 10b is relatively low, as shown in FIG. 5, air flows from the outside to the bottom boundary D over the entire circumference of the bottom boundary D. It flows inside. On the other hand, when the air volume Q is relatively small and the tip velocity Vb of the brush 10b is relatively high, as shown in FIG. 6, a region where the air flow direction is outward in the radial direction in a part of the bottom boundary D. G is produced. In the state shown in FIG. 6, there is a concern that the fine particles wound up by the brush 10b are scattered in the air.

FIG. 7 is a diagram showing the relationship between the speed ratio Va / Vb and the area ratio A _{1 / A.}
In FIG. 7, the horizontal axis is the speed ratio Va / Vb of the speed Va and the tip speed Vb. Here, the velocity Va and the tip velocity Vb are the values represented by the following equations (2) and (3), respectively. The unit of the air volume Q is, for example, [m ³ / min ^-1 ], the unit of the brush diameter Db is, for example, [m], and the unit of the brush rotation speed Nd is, for example, [min ^-1 ].
Va = Q / (60 × A)… Equation (2)
Vb = Db × π × Nd / 60 ... Equation (3)

Further, the vertical axis of FIG. 7 is the area ratio A ₁ / A _{between the area A 1 of} the two regions G (see FIG. 6) in which the radial outward flow occurs at the bottom boundary D and the bottom boundary area A. Is.
As shown in FIG. 7, as the value of the velocity ratio Va / Vb becomes smaller, the value of the area ratio A ₁ / A becomes larger and the amount of fine particles scattered in the air increases. Here, the speed ratio Va / Vb is preferably set to 0.1 or more. The reason is that, as shown in the figure, when the speed ratio Va / Vb is set to 0.1 or more, the area ratio A ₁ / A can be suppressed to less than 0.01, and the fine particles wound up by the brush 10b are put into the air. This is because it is possible to sufficiently suppress the scattering.

The numerical simulation results shown in FIGS. 5 and 6 show the cases where the speed ratios Va / Vb are 0.28 and 0.02, respectively.
As an example of specific parameters in the standard mode of the present embodiment, Dm = 0.95 [m], L = 0.02 [m], Db = 0.12 [m], Nd = 1000 [min ^-1 ]. , Q = 1.0 [m ³ / min ^-1 ], the speed ratio Va / Vb can be set to 0.14.

<Effect of the first embodiment>
As described above, in the mobile air purifier (1) of the present embodiment, air is passed through the filter (3) provided in the housing (2), and the upper end surface (6h2) thereof is the filter (3). An impeller (6) installed at a position higher than the upper end surface (3a), a first motor (6 m) provided in the housing (2) to drive the impeller (6), and a housing (2). A bottom plate (2t) provided at the bottom of the) and formed with a suction port (2i) for sucking air, and a plurality of bottom plates (2t) attached to the housing (2) and separated from the installation surface (Y). A brush width (Db) that includes wheels (9s1, 9s2) and a brush (10b) that protrudes downward from the bottom plate (2t) so as to come into contact with the installation surface (Y), and is the width of the brush (10b). Is the distance from the center point (O) to the farthest point (Pn) in the region of the suction port (2i) from the center point (O) of the brush (10b) in bottom view, which is the outer diameter (Rn) of the suction port. Shorter than twice. Thereby, according to the present embodiment, both the fine particles suspended in the air and the fine particles deposited on the floor surface can be appropriately collected.

The brush width (Db), which is the width of the brush (10b), is the farthest point from the center point (O) in the area of the suction port (2i) from the center point (O) of the brush (10b) in bottom view. It is preferably shorter than twice the suction port outer diameter (Rn), which is the distance to (Pn), and the brush width (Db) is from the center point (O) of the brush (10b) in bottom view to the suction port (2i). ), It is more preferable that the distance from the center point (O) to the shortest point (Pm) is shorter than twice the inner diameter (Rm) of the suction port. This makes it easier to collect the dust rolled up by the brush (10b) from the suction port (2i).
Further, it is more preferable that the mobile air purifier (1) further includes a second motor (9 m1, 9 m2) for driving a plurality of wheels (9s1, 9s2). As a result, the mobile air purifier (1) can be automatically driven.

Further, it is more preferable that the wheel distance (Rw), which is the distance from the center point (O) to the shortest position (Pw) of the wheels (9s1, 9s2), is shorter than the suction port outer diameter (Rn). As a result, dust and the like rolled up by the wheels (9s1, 9s2) can be effectively collected from the suction port (2i).

Further, it is more preferable that the brush (10b) is rotated while sliding with respect to the installation surface (Y). As a result, the brush (10b) can be slid on the installation surface (Y) at a speed faster than the moving speed of the mobile air purifier (1).

Further, it is more preferable to further include a third motor (10 m) for rotating the brush (10b). Thereby, the rotation speed of the brush (10b) can be controlled independently of the rotation speed of the impeller (6).

Further, it is more preferable that the rotation axis (M) of the brush (10b) is in a direction orthogonal to the installation surface (Y). As a result, the brush (10b) can be slid over a wide range of the installation surface (Y).

Further, the length of the outer circumference of the bottom surface of the housing (2) is defined as the bottom surface boundary length Dm, the distance between the suction port (2i) and the installation surface (Y) is defined as the separation distance L, and Dm × L is defined as the bottom surface boundary area A. The air volume by the impeller (6) is the air volume Q, Q / (60 × A) is the speed Va, the brush width (Db) is Db, the rotation speed of the brush (10b) is the brush rotation speed Nd, and Db × When π × Nd / 60 is the tip speed Vb of the brush (10b), it is more preferable that Va / Vb is larger than 0.1. As a result, the amount of fine particles scattered in the air can be effectively suppressed.

Further, it is more preferable that the filter (3) is formed in a cylindrical shape and the radius (R3) of the outer circumference of the filter (3) is shorter than the outer diameter (Rn) of the suction port. This facilitates the formation of an air flow from the outer peripheral surface to the inner peripheral surface of the filter (3).

[Second Embodiment]
FIG. 8 is a bottom view of the mobile air purifier 1C according to the preferred second embodiment. In the following description, the same reference numerals may be given to the parts corresponding to the respective parts of the first embodiment described above, and the description thereof may be omitted.
Instead of the main body suction port 2i (see FIG. 3) of the first embodiment, in the present embodiment, the main body suction port 2i2 is formed on the bottom cover 2t as shown in FIG. The main body suction port 2i2 has a shape in which an oval is curved in an arc shape, and is formed at four positions equally divided in the circumferential direction along the outer circumference of the bottom cover 2t.

Further, instead of the side wheels 9s1, 9s2 (see FIG. 3) in the first embodiment, in the present embodiment, as shown in FIG. 8, the side wheels 9s3, 9s4 are located inside the suction port inner diameter Rm. It is installed. Although the brush 10b (see FIG. 3) is also provided in the present embodiment, the illustration of the brush 10b is omitted in FIG. However, in the present embodiment, the brush diameter Db is shorter than twice the wheel distance Rw. The configuration of the present embodiment other than the above is the same as that of the first embodiment (see FIGS. 1 to 7).

In the present embodiment, the entire side wheels 9s3 and 9s4 are located inside the suction port outer diameter Rn. As a result, the dust and the like rolled up by the side wheels 9s3 and 9s4 can be effectively collected from the main body suction port 2i2, and the dust and the like can be further suppressed from being scattered to the outside (indoor). Further, as shown in FIG. 8, it is more preferable that the entire side wheels 9s3 and 9s4 are positioned inside the suction port inner diameter Rm. This is because the dust and the like rolled up by the side wheels 9s3 and 9s4 can be more effectively collected from the main body suction port 2i2.

[Modification example]
The present invention is not limited to the above-described embodiment, and various modifications are possible. Possible modifications to the above embodiment are, for example, as follows.
(1) In each of the above embodiments, the brush 10b (see FIG. 4) is rotationally driven by the brush motor 10m. However, the brush 10b does not necessarily have to be rotated. That is, even if the brush 10b is fixed to the bottom cover 2t, when the

mobile air purifiers

1 and 1C move, the brush 10b slides on the floor surface Y, so that the fine particles accumulated on the floor surface Y are wound up. Can be done.

(2) In each of the above embodiments, a brush motor 10m for rotationally driving the brush 10b and an impeller motor 6m for rotationally driving the centrifugal impeller 6 are provided. However, one common motor (for example, an impeller motor 6m) may rotate the brush 10b and the centrifugal impeller 6 to drive the brush 10b and the centrifugal impeller 6. As a result, the number of motors can be reduced and the cost of the

mobile air purifiers

1 and 1C can be reduced.

(3)
In each of the above embodiments, the filter 3 is formed in a substantially cylindrical shape, but the filter 3 may be formed by connecting filter plates (not shown) formed in a rectangular plate shape or a curved plate shape in an annular shape. Good.

(4) In each of the above embodiments, the height of the suction port 6i of the centrifugal impeller 6 from the floor surface Y is substantially the same as the height of the upper end surface 3a of the filter 3. However, the suction port 6i may be loosely inserted into the space (unsigned) on the inner peripheral side of the filter 3. In other words, the height of the suction port 6i may be lower than the height of the upper end surface 3a. That is, the upper end surface 3a of the filter 3 may be arranged below the upper end surface 6h2 of the blades 6h of the centrifugal impeller 6.

(5) In each of the above embodiments, the brush 10b has a substantially rectangular plate shape, but the brush 10b may have, for example, a cross shape in the bottom view or an asterisk shape (*).

1 Mobile air purifier 2 Exterior cover (housing)
2i Main unit suction port (suction port)
2t bottom cover (bottom plate)
3 Filter 3a Upper end surface 6 Centrifugal impeller (impeller)
6m impeller motor (first motor)
6h2 Upper end surface 9m1, 9m2 Wheel motor (second motor)
9s1, 9s2 side wheels (wheels)
10b Brush 10m Brush motor (third motor)
M Rotation axis O Center point Y Floor surface (installation surface)
Db brush diameter (brush width)
Pm Shortest point Pn Farthest point Pw Shortest position R3 Radius (outer diameter radius)
Rm Suction port inner diameter Rn Suction port outer diameter Rw Wheel distance

Claims

With the housing
A filter provided in the housing, which is formed in a tubular shape and filters air passing from the outer peripheral surface to the inner peripheral surface.
An impeller provided in the housing to allow air to pass through the filter and whose upper end surface is higher than the upper end surface of the filter.
A first motor provided in the housing and driving the impeller, and
A bottom plate provided at the bottom of the housing and formed with a suction port for sucking air, and a bottom plate.
A plurality of wheels mounted on the housing and separating the bottom plate from the installation surface,
A mobile air purifier comprising: a brush protruding downward from the bottom plate so as to come into contact with the installation surface.
The brush width, which is the width of the brush, is shorter than twice the outer diameter of the suction port, which is the distance from the center point of the suction port to the farthest point in the area of the suction port from the center point of the brush in bottom view. The mobile air purifier according to claim 1, wherein the mobile air purifier is characterized.
The brush width, which is the width of the brush, is shorter than twice the inner diameter of the suction port, which is the distance from the center point to the shortest point in the suction port region from the center point of the brush in bottom view. The mobile air purifier according to claim 2.
The mobile air purifier according to claim 1, further comprising a second motor for driving the plurality of wheels.
The mobile air purifier according to claim 1, wherein the wheel distance, which is the distance from the center point to the shortest position of the wheel, is shorter than the outer diameter of the suction port.
The mobile air purifier according to claim 1, wherein the brush rotates while sliding with respect to the installation surface.
The mobile air purifier according to claim 6, further comprising a third motor for rotating the brush.
The mobile air purifier according to claim 6, wherein the rotation axis of the brush is in a direction orthogonal to the installation surface.
The mobile air purifier according to claim 6, wherein the first motor rotates the brush together with the impeller.
The length of the outer circumference of the bottom surface of the housing is the bottom surface boundary length Dm, the distance between the suction port and the installation surface is the separation distance L, Dm × L is the bottom surface boundary area A, and the air volume by the impeller is the air volume. Q, Q / (60 × A) was the speed Va, the brush width was Db, the rotation speed of the brush was the brush rotation speed Nd, and Db × π × Nd / 60 was the tip speed Vb of the brush. The mobile air purifier according to claim 6, wherein Va / Vb is larger than 0.1.
The mobile air purifier according to claim 1, wherein the filter is formed in a cylindrical shape, and the radius of the outer circumference of the filter is shorter than the outer diameter of the suction port.
With the housing
A first filter provided in the housing and filtering the passing air,
An impeller provided in the housing and
A first motor provided in the housing and driving the impeller, and
A bottom plate provided at the bottom of the housing and formed with a suction port for sucking air, and a bottom plate.
A mobile air purifier comprising a plurality of wheels mounted on the housing and separating the bottom plate from the installation surface.
The mobile air purifier according to claim 12, wherein the suction port is provided so as to face the installation surface.