CN214837231U - Air supply device and electric product - Google Patents

Abstract

The embodiment of the application provides an air supply arrangement and electric product, air supply arrangement includes: a motor having a rotating shaft with a central axis as a rotating center; an impeller fixed to the rotating shaft; a first casing surrounding the impeller, the first casing having an air inlet at a center of one axial end; and a second housing having one axial end abutting against the other axial end of the first housing, the other axial end of the second housing having an air outlet, the second housing having a first wall portion extending in the axial direction and a second wall portion located radially inward of the first wall portion, the second wall portion contracting radially inward as approaching the air outlet in the axial direction. Through the embodiment of the application, the heat dissipation effect of the air supply device can be improved, and meanwhile the air supply device and the real machine are convenient to install.

Description

Air supply device and electric product

Technical Field

The application relates to the electromechanical field, in particular to an air supply device and an electrical product.

Background

Generally, an impeller is provided in the air blowing device. In some existing structures, a side-exhaust static wing structure is arranged on the periphery of an impeller, airflow flowing through the impeller is directly exhausted from the side face of the impeller through the static wing structure, and for a high-speed air supply device, high-frequency sound is easily generated by the structure and is transmitted to the outside of the air supply device to generate noise, so that the noise is difficult to eliminate; in other existing structures, the air supply device adopts a lower-row static wing structure, the lower-row static wing structure is arranged obliquely below the impeller, and the airflow flowing through the impeller is discharged from the lower-row static wing structure after the flow path direction is changed.

It should be noted that the above background description is only for the convenience of clear and complete description of the technical solutions of the present application and for the understanding of those skilled in the art. Such solutions are not considered to be known to the person skilled in the art merely because they have been set forth in the background section of the present application.

SUMMERY OF THE UTILITY MODEL

In order to solve at least one of the above problems or similar problems, embodiments of the present application provide an air supply device and an electrical product, which improve noise reduction effect.

According to a first aspect of embodiments of the present application, there is provided an air blowing device including:

a motor having a rotating shaft with a central axis as a rotating center;

an impeller fixed to the rotating shaft;

a first casing surrounding the impeller, the first casing having an air inlet at a center of one axial end,

a second shell, one axial end of which is abutted against the other axial end of the first shell, the other axial end of the second shell is provided with an air outlet,

wherein the second housing has a first wall portion extending in the axial direction and a second wall portion located radially inward of the first wall portion, the second wall portion contracting radially inward as approaching the outlet port in the axial direction.

In one or more embodiments, the inner peripheral surface of the second wall portion is a continuously curved surface.

In one or more embodiments, the second wall portion is provided with a plurality of through holes.

In one or more embodiments, a sound attenuating element is disposed between the first wall portion and the second wall portion.

In one or more embodiments, the first wall portion is cylindrical.

In one or more embodiments, the motor includes a circuit board disposed perpendicular to an axial direction, and a radial dimension of the circuit board is larger than a radial dimension of the air outlet.

In one or more embodiments, a sealing member is provided radially outside the rotating shaft, and the impeller is closer to the intake port than the sealing member.

In one or more embodiments, the second housing is provided at an outer circumference thereof with a mounting portion.

In one or more embodiments, the area of the air outlet is 1-2 times that of the air inlet.

In one or more embodiments, the air intake opening, the impeller, a first space radially inside the second housing where the second wall portion is not provided, a second space radially inside the second wall portion near one end of the air intake opening, and the air outlet form a fluid passage,

the cross-sectional area of the second space of the fluid passage at the radially inner side of the second wall portion near the end of the air inlet is larger than the cross-sectional area of the first space of the fluid passage at the radially inner side of the second housing where the second wall portion is not provided, and is also larger than the cross-sectional area of the fluid passage at the air outlet.

According to a second aspect of embodiments of the present application, there is provided an electric product including the air blowing device of the first aspect described above.

One of the beneficial effects of the embodiment of the application lies in: form the longer flow path in route between air supply arrangement's air intake and the air outlet, can improve noise reduction effect to the radial inboard setting of the first wall portion that extends along the axial has the second wall portion of binding off structure, can enough change the flow path direction through the binding off structure of second wall portion, further noise reduction can also make things convenient for air supply arrangement and real machine's installation through the first wall portion that extends along the axial.

Specific embodiments of the present application are disclosed in detail with reference to the following description and drawings, indicating the manner in which the principles of the application may be employed. It should be understood that the embodiments of the present application are not so limited in scope. The embodiments of the application include many variations, modifications and equivalents within the spirit and scope of the appended claims.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the application, are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application. It is obvious that the drawings in the following description are only some embodiments of the application, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. In the drawings:

FIG. 1 is a schematic view of an air supply apparatus according to an embodiment of the first aspect of the present application;

FIG. 2 is another schematic view of an air supply apparatus according to an embodiment of the first aspect of the present application;

FIG. 3 is a schematic axial cross-section of an air-moving device in accordance with an embodiment of the first aspect of the present application;

FIG. 4 is a partially schematic illustration of an example of a second housing in accordance with an embodiment of the first aspect of the present application;

FIG. 5 is a further schematic view of an air-moving device according to an embodiment of the first aspect of the present application;

FIG. 6 is a further schematic view of an air supply arrangement according to an embodiment of the first aspect of the present application;

FIG. 7 is a partially schematic illustration of another example of a second housing in accordance with an embodiment of the first aspect of the present application;

FIG. 8 is a schematic view of an air-moving device including the second housing shown in FIG. 7;

fig. 9 is an axial cross-sectional view of an air blowing device including the second casing shown in fig. 7.

Detailed Description

The foregoing and other features of the present application will become apparent from the following description, taken in conjunction with the accompanying drawings. In the description and drawings, particular embodiments of the application are disclosed in detail as being indicative of some of the embodiments in which the principles of the application may be employed, it being understood that the application is not limited to the described embodiments, but, on the contrary, is intended to cover all modifications, variations, and equivalents falling within the scope of the appended claims.

In embodiments of the present application, the term "and/or" includes any and all combinations of one or more of the associated listed terms. The terms "comprising," "including," "having," and the like, refer to the presence of stated features, elements, components, and do not preclude the presence or addition of one or more other features, elements, components, and elements.

In the embodiments of the present application, the singular forms "a", "an", and the like may include the plural forms and should be interpreted broadly as "a" or "an" and not limited to the meaning of "a" or "an"; furthermore, the term "comprising" should be understood to include both the singular and the plural, unless the context clearly dictates otherwise. Further, the term "according to" should be understood as "at least partially according to … …," and the term "based on" should be understood as "based at least partially on … …," unless the context clearly dictates otherwise.

In the following description of the present application, for the sake of convenience of description, a direction extending along or parallel to the central axis OO' of the motor of the air blowing device is referred to as an "axial direction", and a direction from the air outlet of the air blowing device to the air inlet of the air blowing device is referred to as an "upper side" or an "axially upper side" or an "axial side"; the direction from the air inlet of the air supply device to the air outlet of the air supply device is called as the lower side or the axial other side; a radial direction around the central axis OO 'is referred to as a "radial direction", a direction approaching the central axis OO' is referred to as a "radially inner side" or an "inner side", a direction away from the central axis OO 'is referred to as a "radially outer side" or an "outer side", and a direction around the central axis OO' is referred to as a "circumferential direction". However, it should be noted that these are for convenience of explanation only, and do not limit the direction of the blower when used or manufactured.

Embodiments of the present application will be described below with reference to the drawings.

Embodiments of the first aspect

An embodiment of a first aspect of the present application provides an air supply device.

FIG. 1 is a schematic view of an air supply apparatus according to an embodiment of the first aspect of the present application, showing the air supply apparatus as viewed from the side of an air inlet; FIG. 2 is another schematic view of the air supply apparatus according to the first embodiment of the present application, showing the air supply apparatus as viewed from the air outlet side; fig. 3 is a schematic view of an axial cross section of an air blowing device according to an embodiment of the first aspect of the present application.

As shown in fig. 1 to 3, the air blowing device of the embodiment of the present application includes a motor 10, an impeller 20, a first casing 30, and a second casing 40.

The motor 10 has a rotary shaft 11 having a central axis OO ' as a rotation center, the impeller 20 is fixed to the rotary shaft 11, the first casing 30 surrounds the impeller 20, the first casing 30 has an air inlet 31 at a center of one axial end (O end), one axial end (O end) of the second casing 40 abuts against the other axial end (O ' end) of the first casing 30, and the other axial end (O ' end) of the second casing 40 has an air outlet 41.

As shown in fig. 3, the second housing 40 has a first wall portion 42 extending in the axial direction and a second wall portion 43 located radially inward of the first wall portion 42, and the second wall portion 43 contracts radially inward as it approaches the outlet port 41 in the axial direction.

According to the above embodiments of the present invention, a flow path with a long path is formed between the air inlet 31 and the air outlet 41 of the air supply device, which can improve the noise reduction effect, and the second wall portion 43 having the closing structure is disposed on the radial inner side of the first wall portion 42 extending in the axial direction, which can change the flow path direction by the closing structure of the second wall portion 43, further reduce the noise, and facilitate the installation of the air supply device and the actual machine by the first wall portion 42 extending in the axial direction.

In the embodiment of the present application, the motor 10 may be of any type, and the motor 10 may further include a rotor, a stator, a bearing 12 (see fig. 3), and the like, in addition to the rotating shaft 11, as referred to in the related art. The second housing 40 may enclose at least a portion of the motor 10, for example, the second housing may enclose a rotor, a stator, and a bearing 12 of the motor 10, and a portion of the rotating shaft 11 is located inside the second housing 40.

In one or more embodiments, as shown in fig. 3, a sealing member 50 is disposed radially outward of the rotating shaft 11, and the impeller 20 is closer to the intake port 31 than the sealing member 50, that is, the sealing member 50 is disposed below the impeller 20 on the rotating shaft 11. Accordingly, impurities, moisture, and the like in the gas flowing through the impeller 20 can be prevented from flowing into the motor through the rotary shaft 11, for example, as shown in fig. 3, the bearing 12 positioned below the seal member 50 is provided on the outer periphery of the rotary shaft 11, and damage to the bearing 12 by the impurities and moisture can be prevented by the seal member 50. Thereby prolonging the service life of the air supply device.

In one or more embodiments, as shown in fig. 1 and 2, the second housing 40 may be provided at an outer circumference thereof with a mounting portion 60, whereby the air supply device can be mounted and fixed to a real machine, which is another component of any electric product to which the air supply device can be applied, other than the air supply device, such as a sweeping robot, a vacuum cleaner, and the like, through the mounting portion 60.

In the embodiment of the present application, the mounting portion 60 may be provided at any position of the outer periphery of the second housing 40, for example, at a position near the axial O' side of the outer periphery of the second housing 40 shown in fig. 1 and 2; further, the number of the mounting portions 60 may be any number, for example, 3 shown in fig. 1 and 2, but is not limited thereto, and the number of the mounting portions 60 may also be 1, 2, or 3 or more, and in the case of having a plurality of mounting portions 60, the plurality of mounting portions 60 may be provided at the outer periphery of the second housing 40 at equal intervals or at unequal intervals in the circumferential direction.

In one or more embodiments, as shown in fig. 3, the air inlet 31, the impeller 20, the first space 44 on the radially inner side of the second housing 40 where the second wall portion 43 is not provided, the second space 45 on the radially inner side of the second wall portion 43 near one end of the air inlet 31, and the air outlet 41 form a fluid passage P.

In the embodiment of the present application, the second casing 40 includes a portion provided with the second wall portion 43 on the radially inner side and a portion provided with no second wall portion 43 on the radially inner side, in other words, the second wall portion 43 may be provided at a position of a portion of the second casing 40 on the radially inner side of the first wall portion 42, for example, as shown in fig. 3, the second wall portion 43 may be provided at a position of the first wall portion 42 on the radially inner side close to the air outlet 41, and the second wall portion 43 may not be provided at a position of the first wall portion 42 on the radially inner side close to the air inlet 31, but is not limited thereto, the second wall portion 43 may be provided at another position on the radially inner side of the first wall portion 42, and a space on the radially inner side of the portion provided with no second wall portion 43 may be referred to as a first space 44. In addition, the space radially inside the portion of the second casing 40 radially inside which the second wall portion 43 is not provided may be provided with other components, for example, a stationary wing 46 may be provided to change the flow direction and the flow rate of the fluid.

In the embodiment of the present application, the sectional area of the second space 45 of the fluid passage P on the radially inner side of the second wall portion 43 near the end (O end) of the intake port 31 is larger than the sectional area of the first space 44 of the fluid passage P on the radially inner side of the second housing 40 where the second wall portion 43 is not provided, and the sectional area of the second space 45 of the fluid passage P on the radially inner side of the second wall portion 43 near the end (O end) of the intake port 31 is also larger than the sectional area of the fluid passage P at the outlet port 41. Here, the sectional area of the fluid passage P at each position means an area of a fluid section obtained by cutting the fluid at each position of the fluid passage P in a plane perpendicular to a flow direction of the fluid flowing through the corresponding position. Thus, by forming the fluid passage with the cross-sectional area constantly changing, the acoustic energy is attenuated repeatedly, and the noise reduction effect can be further improved.

In the embodiment of the present application, the second wall portion 43 is in a closing-in structure, so as to realize a fluid passage in which the size of the cross-sectional area of the fluid passage P is changed constantly, and as shown in fig. 3, the second wall portion 43 and the motor 10 are directly communicated, that is, no other component is provided between the second wall portion 43 and the motor 10, so that the fluid passage P has a larger cross-sectional area in the second space 45 of the second wall portion 43 near one end (O end) of the air inlet 31, so as to further realize the size change of the cross-sectional area of the fluid passage P, and it is also possible to increase the contact area of the fluid with the motor inside the air supply device, so as to enhance the heat dissipation effect, but the present application is not limited thereto, and other components are provided so that the cross-sectional area of the second space 45 of the fluid passage P on the radial inner side of the second wall portion 43 near one end (O end) of the air inlet 31 is larger than the cross-sectional area of the first space 44 of the fluid passage P on the radial inner side where the second wall portion 43 is not provided with the second wall portion 43 on the radial inner side of the second housing 40 The cross-sectional area of the fluid passage P at the air outlet 41 may be larger than the cross-sectional area of the fluid passage P.

In the embodiment of the present application, as shown in fig. 3, the airflow flows into the impeller 20 from the air inlet 31, the sectional area of the fluid passage P at the impeller 20 is increased, the airflow expands, the flow velocity is reduced, and the noise of the fluid is attenuated once; then, the fluid passes through the first space 44 of the radially inner side of the second housing 40 where the second wall portion 43 is not provided, the fluid is compressed, the fluid after being compressed is expanded again in the second space 45 of the second wall portion 43 at the end (O end) near the intake port 31, and the fluid undergoes the re-attenuation. Thus, the noise can be greatly reduced by subjecting the fluid to at least two attenuations, and the flow direction of the fluid changes many times along the fluid passage P within the fluid passage P, and the noise can be further reduced.

In one or more embodiments, as shown in fig. 3, the inner peripheral surface of the second wall portion 43 is a continuous curved surface S, whereby the noise reduction effect can be further improved. However, the inner circumferential surface of the second wall portion 43 may be an inclined surface, for example.

In one or more embodiments, as shown in fig. 3, the first wall portion 42 is cylindrical, thereby facilitating the operation of mounting the motor 10 inside the second housing 40. However, the present invention is not limited to this, and the first wall portion 42 may be tapered, for example. The air blowing device can be miniaturized.

In one or more embodiments, as shown in fig. 3, the motor 10 includes the circuit board 13 disposed perpendicular to the axial direction, and the radial dimension D of the circuit board 13 is larger than the radial dimension D of the air outlet 41, or the radially outermost side of the circuit board 13 may be located at a distance from the central axis OO' larger than the radially innermost side of the second wall portion 43. Therefore, the necking structure can be further contracted without being limited by the radial size of the circuit board, the change range of the flow path direction is increased, the noise reduction effect is further enhanced, fluid can fully flow through motor components such as the circuit board and the like, and the heat dissipation effect can be further improved. However, the present application is not limited thereto, and the radial dimension of the circuit board 13 may be smaller than or equal to the radial dimension of the air outlet 41.

Fig. 4 is a partially schematic view of an example of a second housing in an embodiment of the first aspect of the present application, showing the second housing sectioned in an axial direction.

In the embodiment of the present application, as shown in fig. 3 and 4, the second housing 40 includes a first wall portion 42 and a second wall portion 43 located radially inside the first wall portion 42, and the first wall portion 42 and the second wall portion 43 may be formed separately or integrally, for example, the first wall portion 42 and the second wall portion 43 may be formed integrally by injection molding. Further, the first wall portion 42 and the second wall portion 43 may be formed separately, and then the second wall portion 43 may be attached to the radially inner side of the first wall portion 42. The freedom of assembling the air supply device can be realized.

In some embodiments of the present application, in the case where the first wall portion 42 and the second wall portion 43 are separately molded, as shown in fig. 3 and 4, the inner diameter dimension of the first wall portion 42 may be made larger than the radial dimension D of the circuit board 13, and the inner diameter dimension of the second wall portion 43 (i.e., the radial dimension D of the air outlet 41) may be made smaller than the radial dimension D of the circuit board 13. Accordingly, the components of the motor 10 including the circuit board 13 can be easily mounted in the second casing 40, and the second wall portion 43 is mounted radially inward of the first wall portion 42 after the motor 10 is mounted in the second casing 40, whereby the contraction structure can be further contracted, the width of the change in the flow path direction can be increased, and the noise reduction effect can be further enhanced.

In one or more embodiments, as shown in fig. 3 and 4, in the case where the first wall portion 42 and the second wall portion 43 are molded separately, the second wall portion 43 may include a cylindrical wall portion 431 and an arc-shaped wall portion 432 located radially outside the cylindrical wall portion 431 and having a closed-off shape toward the outlet 41 side. Thus, the second wall portion 43 can be easily inserted and attached to the first wall portion 42 by the close contact between the cylindrical wall portion 431 and the first wall portion 42. Further, a step portion may be formed on the inner peripheral surface of the first wall portion 42, and the second wall portion 43 may be inserted into the first wall portion 42 and brought into contact with the step portion, whereby the second wall portion 43 can be positioned in the axial direction with respect to the first wall portion 42. However, the present invention is not limited to this, and the second wall portion 43 may have only the arc-shaped wall portion 432.

In one or more embodiments, the area of the air outlet is 1-2 times that of the air inlet. Therefore, the air supply device can smoothly exhaust air. For example, the area of the outlet may be 1.75 times the area of the inlet.

It should be noted that the area of the air inlet here is the area of the opening at one axial end of the first housing, and the area of the air outlet represents the cross-sectional area of the fluid passage at the air outlet, in other words, the area of the air outlet represents the area of the portion of the opening at the other axial end of the second housing for flowing the fluid, and the area of the air outlet is smaller than or equal to the area of the opening at the other axial end of the second housing. The following description will be made with reference to fig. 5 and 6.

Fig. 5 is a further schematic view of the air blowing device according to the first embodiment of the present application, as viewed from the axial direction O side in the axial direction toward the air blowing device, and fig. 6 is a further schematic view of the air blowing device according to the first embodiment of the present application, as viewed from the axial direction O' side in the axial direction toward the air blowing device.

As shown in fig. 5, the area of the air inlet is the area of a circle with r1 as a radius shown in fig. 5, where r1 represents the distance from the central axis OO ' to the edge of the air inlet of the first housing 30, as shown in fig. 6, the area of the air outlet is the difference between the area of a large circle with r2 as a radius shown in fig. 6 and the area of a small circle with r3 as a radius, where r2 represents the distance from the central axis OO ' to the inner circumferential surface of the second wall portion 43, and r3 represents the distance from the central axis OO ' to the outer circumference of the motor 10.

FIG. 7 is a partially schematic illustration of another example of a second housing in an embodiment of the first aspect of the present application, showing the second housing sectioned in an axial direction; fig. 8 is a schematic view of an air blowing device including the second casing of the example shown in fig. 7, showing the air blowing device as viewed from the air outlet side; fig. 9 is an axial cross-sectional view of an air blowing device including the second casing of the example shown in fig. 7.

In one or more embodiments, as shown in fig. 7 to 9, the second wall portion 43 is provided with a plurality of through holes 433, whereby the amount of air discharged can be increased by the through holes, and the heat radiation effect can be further improved.

In the embodiment of the present application, the number of the through holes 433 is not limited, and the plurality of through holes 433 may be provided at equal intervals in the circumferential direction on the second wall portion 43, but the present invention is not limited thereto, and the plurality of through holes 433 may be provided at unequal intervals in the circumferential direction on the second wall portion 43.

In one or more embodiments, a sound attenuating element, such as sound attenuating cotton, may be disposed between the first wall portion 42 and the second wall portion 43. Therefore, the noise reduction effect can be further enhanced while the heat dissipation effect is improved.

For example, as shown in fig. 7 to 9, a gap 47 may be formed between the first wall portion 42 and the second wall portion 43, and by disposing the silencing cotton in the gap 47, for example, at a position covering the through hole 433 in the gap 47, the effects of heat dissipation and noise reduction are further achieved.

Further, there may be no gap between the first wall portion 42 and the second wall portion 43, and for example, the second wall portion 43 may be formed to extend radially inward from the inner peripheral surface of the first wall portion 42. Therefore, the die can be simplified, and the production cost can be reduced.

The air blowing device according to the embodiments of the present invention is described above in terms of different embodiments, and the above embodiments may be combined arbitrarily, and the description thereof is omitted here. Further, the present application has been described above only by way of example, but the present application is not limited thereto, and appropriate modifications may be made on the basis of the above respective embodiments.

It should be noted that, only the structure of the air blowing device related to the present application is described above, the air blowing device may further include other structures, such as the conducting wire 70 shown in fig. 1, and the related art may be specifically referred to, and the description is omitted here. It is also possible to add components not shown in fig. 1 to 9 or to reduce one or more components in fig. 1 to 9. As for other configurations and structures of the air blowing device, the related art can be referred to, and the description thereof is omitted here.

According to the above embodiments of the present application, a flow path with a long path is formed between the air inlet 31 and the air outlet 41 of the air supply device, which can improve the noise reduction effect, and the second wall portion 43 with the closing structure is disposed on the radial inner side of the first wall portion 42 extending in the axial direction, which can change the flow path direction through the closing structure of the second wall portion 43, further reduce noise, and facilitate the installation of the air supply device and the actual machine through the first wall portion 42 extending in the axial direction.

Embodiments of the second aspect

Embodiments of the second aspect of the present application provide an electrical product having the air supply device described in the embodiments of the first aspect. Since the structure of the air blowing device has been described in detail in the embodiment of the first aspect, the contents thereof are incorporated herein, and the description thereof is omitted here.

In the embodiment of the present application, the electric product may be any device or equipment using the air supply device 10, including various home appliances, office automation equipment, industrial equipment, vehicle-mounted devices, or components in various equipment, such as a cleaning robot, a vacuum cleaner, and the like.

According to the embodiment of the present application, in the electric product including the air supply device of the first aspect, the flow path with a long path is formed between the air inlet 31 and the air outlet 41 of the air supply device, so that the noise reduction effect can be improved, and the second wall portion 43 having the closing structure is disposed on the radial inner side of the first wall portion 42 extending in the axial direction, so that the flow path direction can be changed by the closing structure of the second wall portion 43, and the noise can be further reduced, and the first wall portion 42 extending in the axial direction can facilitate the installation of the air supply device and other components of the electric product.

The present application has been described in conjunction with specific embodiments, but it should be understood by those skilled in the art that these descriptions are intended to be illustrative, and not limiting. Various modifications and adaptations of the present application may occur to those skilled in the art based on the spirit and principles of the application and are within the scope of the application.

Preferred embodiments of the present application are described above with reference to the accompanying drawings. The many features and advantages of the embodiments are apparent from the detailed specification, and thus, it is intended by the appended claims to cover all such features and advantages of the embodiments that fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the embodiments of the present application to the exact construction and operation illustrated and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope thereof.

Claims (11)

1. An air supply arrangement, comprising:

a motor having a rotating shaft with a central axis as a rotating center;

an impeller fixed to the rotating shaft;

a first casing surrounding the impeller, the first casing having an air inlet at a center of one axial end,

a second shell, one axial end of which is abutted against the other axial end of the first shell, the other axial end of the second shell is provided with an air outlet,

it is characterized in that the preparation method is characterized in that,

the second housing has a first wall portion extending in the axial direction and a second wall portion located radially inward of the first wall portion, the second wall portion contracting radially inward as approaching the outlet port in the axial direction.

2. The air supply arrangement according to claim 1,

the inner peripheral surface of the second wall portion is a continuous curved surface.

3. The air supply arrangement according to claim 1,

the second wall portion is provided with a plurality of through holes.

4. The air supply arrangement according to claim 3,

a sound attenuating member is disposed between the first wall portion and the second wall portion.

5. The air supply arrangement according to claim 1,

the first wall portion is cylindrical.

6. The air supply arrangement of claim 5,

the motor includes a circuit board disposed perpendicular to an axial direction,

the radial dimension of the circuit board is larger than that of the air outlet.

7. The air supply arrangement according to claim 1,

and a sealing part is arranged on the radial outer side of the rotating shaft, and the impeller is closer to the air inlet than the sealing part.

8. The air supply arrangement according to claim 1,

the periphery of the second shell is provided with a mounting part.

9. The air supply arrangement according to claim 1,

the area of the air outlet is 1-2 times of the area of the air inlet.

10. The air supply arrangement according to claim 1,

the air inlet, the impeller, a first space on the radial inner side of the second shell, which is not provided with the second wall part, a second space on the radial inner side of the second wall part, which is close to one end of the air inlet, and the air outlet form a fluid channel,

the cross-sectional area of the second space of the fluid passage at the radially inner side of the second wall portion near the end of the air inlet is larger than the cross-sectional area of the first space of the fluid passage at the radially inner side of the second housing where the second wall portion is not provided, and is also larger than the cross-sectional area of the fluid passage at the air outlet.

11. An electric product characterized in that the electric product has the air blowing device of any one of claims 1 to 10.

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