IMPELLER AND BLOWER

Abstract

A blower includes an impeller rotatable about a central axis and a motor driving the impeller. The impeller includes a first impeller, and a second impeller connected to the first impeller. The first impeller includes a base and first blades arranged in a circumferential direction. The base includes a cup portion of which an axially upper end is closed and a flange extending radially outward from an axially lower end of the cup portion. The second impeller includes a shroud with an annular or substantially annular shape about the central axis and axially opposes an upper surface of the flange, and second blades arranged in the circumferential direction. Each first blade protrudes axially upward from the flange. Each second blade protrudes axially downward from the shroud.

Description

1. FIELD OF THE INVENTION

The present disclosure relates to an impeller and a blower.

2. BACKGROUND

In the related art, a centrifugal fan is known, which radially outward sends out air taken in the fan by a rotation of an impeller. For example, in related art, a centrifugal blower fan is known, in which a motor and an impeller are accommodated inside a casing. The impeller integrally includes a plurality of blades, an annular band which is defined by joining one end side of the plurality of blades into one, and a flat donut-shaped disk which is defined by joining the other side of the plurality of blades into one. A claw located on the disk side of the impeller is inserted into a notch which is provided in a flange of a bottomed cylindrical back yoke. Accordingly, the impeller is fixed to the back yoke constituting a rotor of the motor.

However, in the centrifugal blower fan of the related art, a portion of the air taken into the impeller may escape to the outside from a gap between the disk and the back yoke on the one end side of the plurality of blades. In this case, it is not possible to radially outward send out the air taken into the impeller efficiently.

SUMMARY

An example embodiment of an impeller of the present disclosure is rotatable about a central axis extending in an axial direction. The impeller includes a first impeller, and a second impeller connected to the first impeller. The first impeller includes a base and a plurality of first blades arranged in a circumferential direction. The base includes a cup portion of which an axially upper end is closed and a flange extending radially outward from an axially lower end of the cup portion. The second impeller includes a shroud and a plurality of second blades. The shroud has an annular or substantially annular shape about the central axis and opposes an upper surface of the flange in an axial direction. The second blades are arranged in the circumferential direction. Each of the first blades protrudes axially upward from the flange. Each of the second blades protrudes axially downward from the shroud. In the circumferential direction, at least one second blade is located between the first blades adjacent to each other.

An example embodiment of a blower of the present disclosure includes the impeller which is rotatable about the central axis and a motor which drives the impeller.

The above and other elements, features, steps, characteristics and advantages of the present disclosure will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view illustrating a configuration example of a centrifugal fan according to an example embodiment of the present disclosure.

FIG. 2 is a perspective view of an impeller according to an example embodiment of the present disclosure when viewed from an axially upper side.

FIG. 3 is an exploded perspective view of the impeller.

FIG. 4 is an enlarged perspective view of a second impeller according to an example embodiment of the present disclosure when viewed from an axially lower side.

FIG. 5 is a top view of the impeller.

FIG. 6 is a cross-sectional view illustrating a configuration example of a fixing portion according to an example embodiment of the present disclosure.

FIG. 7 is a cross-sectional view illustrating another configuration example of the fixing portion according to an example embodiment of the present disclosure.

DETAILED DESCRIPTION

Hereinafter, example embodiments of the present disclosure will be described with reference to the drawings.

In the present specification, in an impeller 100 and a centrifugal fan 200, a direction parallel to a central axis CA is referred to as an “axial direction”. Furthermore, in the axial direction, a direction from a first impeller 1 to a second impeller 2 is referred to as an “axially upper side”, and a direction from the second impeller 2 to the first impeller 1 is referred to as an “axially lower side”. In each component, an end on the axially upper side is referred to as an “axially upper end”, and an end on the axially lower side is referred to as an “axially lower end”. Further, in surfaces of each component, a surface facing the axially upper side is referred to as an “upper surface”, and a surface facing the axially lower side is referred to as a “lower surface”.

A direction orthogonal to the central axis CA is referred to as a “radial direction”, and a rotation direction about the central axis CA is referred to as a “circumferential direction”. Further, in the radial direction, a direction toward the central axis CA is referred to as a “radially inner side”, and a direction away from the central axis CA is referred to as a “radially outer side”. In each component, an end on the radially inner side is referred to as a “radially inner end”, and an end on the radially outer side is referred to as a “radially outer end”. In addition, in side surfaces of each component, a side surface facing the radially inner side is referred to as an “inner side surface”, a side surface facing the radially outer side is referred to as an “outer side surface”, and a side surface facing the circumferential direction is referred to as a “circumferential side surface”.

Moreover, the above-described designations with respect to the directions and the surfaces do not indicate a positional relationship and a direction when incorporated in an actual device.

FIG. 1 is a cross-sectional view illustrating a configuration example of the centrifugal fan 200. Moreover, in FIG. 1, the centrifugal fan 200 is cut along a cut surface including the central axis CA. As illustrated in FIG. 1, the centrifugal fan 200 is a blower including the impeller 100 and a motor 110 which rotationally drives the impeller 100. The impeller 100 is attached to a rotor (not illustrated) of the motor 110, and is rotatable about the central axis CA extending vertically, together with the rotor.

FIG. 2 is a perspective view of the impeller 100 when viewed from the axially upper side. FIG. 3 is an exploded perspective view of the impeller 100. The impeller 100 includes the first impeller 1 and the second impeller 2 which is connected to the first impeller 1. According to this configuration, the first impeller 1 and the second impeller 2 are assembled to each other in the vertical direction, and thus, the impeller 100 is able to be obtained.

The first impeller 1 has a base 11 and a plurality of first blades 12 which are arranged in the circumferential direction. The base 11 has a cup portion 111 extending in the axial direction and an annular flange 112. An axially upper end of the cup portion 111 is closed. An axially lower end of the cup portion 111 is open, and an upper portion of the motor 110 is accommodated in the cup portion 111 through an opening of the axially lower end. The flange 112 extends radially outward from the axially lower end of the cup portion 111.

A first groove 11a and a through-hole 11b are provided in the base 11. In other words, the base 11 further includes the first groove 11a and the through-hole 11b. The first groove 11a is provided on an upper surface of the flange 112 of the base 11. The first groove 11a is recessed axially downward between the first blades 12 adjacent to each other in the circumferential direction. The first groove 11a extends in a direction including at least a radial component of the radial component and a circumferential component. The through-hole 11b is provided in a radially inner end of the first groove 11a and penetrates the base 11 in the axial direction.

If the impeller 100 rotates, air flows in from an annular shroud 21. That is, the air flows in from the radially inner side rather than a radially inner peripheral edge 21b of the shroud 21. Each of the first blades 12 protrudes axially upward from an upper surface of at least flange 112 of the base 11. Therefore, a gap is not defined between the first blades 12 and the flange 112. Accordingly, the air does not escape in the circumferential direction through the gap. Therefore, when the impeller 100 rotates, the first blades 12 are able to efficiently send out the air to the radially outer side of the impeller 100. The first blade 12 extends in a direction including at least a radial component of the radial component and a circumferential component.

FIG. 4 is an enlarged perspective view of the second impeller 2 when viewed from the axially lower side. The second impeller 2 has a shroud 21 and a plurality of second blades 22 which are arranged in the circumferential direction.

The shroud 21 has an annular or substantially annular shape about the central axis CA and faces the base 11 of the first impeller 1 in the axial direction. In the example embodiment of the present disclosure, the shroud 21 faces the upper surface of the flange 112 of the base 11 in the axial direction. A second groove 21a is provided on a lower surface of the shroud 21. In other words, the shroud 21 has the second groove 21a. The second groove 21a is recessed axially upward between the second blades 22 adjacent to each other in the circumferential direction. The second groove 21a extends in a direction including at least a radial component of the radial component and a circumferential component.

The second groove 21a extends along the first blade 12 when viewed in the axial direction. Therefore, in a case where the second impeller 2 is connected to the first impeller 1, an axially upper end of the first blade 12 is located in the second groove 21a. Thereby, even in a case where a gap is defined between the first blade 12 and the shroud 21, it is possible to prevent the air from leaking from a portion between the first blade 12 and the shroud 21. Accordingly, when the impeller 100 rotates, it is possible to suppress a decrease in efficiency which the air is sent to the radially outer side of the impeller 100 by the first blades 12.

Each of the second blades 22 protrudes axially downward from the shroud 21. Therefore, a gap is not defined between the second blades 22 and the shroud 21. Accordingly, when the impeller 100 rotates, the second blades 22 are able to efficiently send out the air to the radially outer side of the impeller 100.

The second blade 22 extends in a direction including at least a radial component of the radial component and a circumferential component. FIG. 5 is a top view of the impeller 100. In addition, in FIG. 5, the shroud 21 is indicated by broken lines. When viewed in the axial direction, as illustrated in FIG. 5, each of the second blades 22 extends along the first groove 11a of the base 11. Therefore, in the case where the second impeller 2 is connected to the first impeller 1, an axially lower end of the second blade 22 is located in the first groove 11a. Thereby, even in the case where a gap is defined between the second blade 22 and the base 11, it is possible to prevent the air from leaking from a portion between the second blade 22 and the base 11. Accordingly, when the impeller 100 rotates, it is possible to suppress a decrease in efficiency which the air is sent to the radially outer side of the impeller 100 by the second blades 22.

In the example embodiment of the present disclosure, the axially lower ends of all the second blade portions 22 are located in the respective first grooves 11a. However, the present disclosure is not limited to this example, and the axially lower ends of some of the second blades 22 may be located in the first grooves 11a. In other words, in the circumferential direction, the axially lower end of at least one second blade 22 may be located in the first groove 11a.

In the case where the second impeller 2 is connected to the first impeller 1, in the circumferential direction, the second blade 22 is located between the first blades 12 adjacent to each other. That is, the second blade 22 is located between the first blades 12 adjacent to each other in the circumferential direction. Thereby, blowing efficiency of impeller 100 is further improved.

In the example embodiment of the present disclosure, all the second blades 22 are located between the first blades 12 adjacent to each other. However, the present disclosure is not limited to this example, and some of the second blades 22 may be located between the first blades 12 adjacent to each other. In other words, in the circumferential direction, at least one second blade 22 may be located between the first blades 12 adjacent to each other.

When viewed in the axial direction, as illustrated in FIG. 5, a radially inner end of the second blade 22 is located radially outside a radially inner end of the first blade 12. Accordingly, it is possible to prevent a gap between the first blade 12 and the second blade 22 from being narrowed which occurs because the first blade 12 and the second blade 22 are adjacent to each other at the radially inner end. Accordingly, a flow of the air flowing through a portion between the first blades 12 adjacent to each other is not able to be easily hindered.

Moreover, when viewed in the axial direction, as illustrated in FIG. 5, the radially inner end of the second blade 22 is located radially outside a radially outer end of the cup portion 111. Accordingly, when the second impeller 2 is connected to the first impeller 1, it is possible prevent the second blades 22 from abutting on the cup portion 111. Therefore, a connection operation of the first impeller 1 and the second impeller 2 is easily performed.

As illustrated in FIG. 5, when viewed in the axial direction, a length in an extension direction of the second blade 22 is shorter than a length in an extension direction of the first blade 12. Accordingly, when the second impeller 2 is connected to the first impeller 1, the second blade 22 does not easily abut on the cup portion 111. Therefore, a connection operation of the first impeller 1 and the second impeller 2 is easily performed.

A fixing portion 221 is provided in the axially lower end of the second blade 22. In other words, the second blade 22 has the fixing portion 221. The fixing portion 221 extends axially downward from the second blade 22 and is fixed to the base 11 through the through-hole 11b. Accordingly, the second impeller 2 is able to be easily connected to the first impeller 1. Moreover, in the example embodiment the present disclosure, the fixing portion 221 is provided in all the second blade portions 22. However, the present disclosure is not limited to this example, and the fixing portion 221 may be provided in some second blades 22. In other words, the fixing portion 221 may be provided in at least one second blade 22 in the circumferential direction.

The impeller 100 further has a filler 3. The filler 3 is provided inside the through-hole 11b through which the fixing portion 221 passes. In the through-hole 11b, the filler 3A fills a portion between the fixing portion 221 and an radially inner side surface of the through-hole 11b. According to the filling of the filler 3, it is possible to prevent the air flowing between the first blades 12 from leaking in the axial direction through the through-hole 11b.

FIG. 6 is a cross-sectional view illustrating a configuration example of the fixing portion 221. As illustrated in FIG. 6, the fixing portion 221 has a claw 221a. After the fixing portion 221 passes through the through-hole 11b, the claw 221a is hooked to a lower surface of the base 11. Accordingly, when the impeller 100 is assembled, the second impeller 2 is able to be easily connected to the first impeller 1. Moreover, in the example embodiment of the present disclosure, the claw 221a is provided in all the second blade portions 22. However, the present disclosure is not limited to this example, and the claw 221a may be provided in some second blades 22. In other words, the claw 221a may be provided in at least one second blade 22 in the circumferential direction.

In a case where the claw 221a is hooked to the lower surface of the base 11, as illustrated in FIG. 6, an upper surface of the claw 221a is in contact with the lower surface of the base 11. Further, the axially lower end of the second blade 22 inserted into the first groove 11a faces a bottom surface of the first groove 11a with a gap between the bottom surface of the first groove 11a and the axially lower end of the second blade 22. That is, when the second impeller 2 is connected to the first impeller 1, first, the upper surface of the claw 221a and the lower surface of the base 11 come into contact with each other. Accordingly, it is possible to prevent a gap from being generated between the upper surface of the claw 221a and the lower surface of the base 11. Therefore, it is possible to increase connection strength between the first impeller 1 and the second impeller 2.

Moreover, the claw 221a is covered with the filler 3 outside the through-hole 11b. Accordingly, at least a portion of the claw 221a is able to be fixed to the base 11 by the filler 3, and thus, it is possible to further increase the connection strength between the first impeller 1 and the second impeller 2. In addition, in the example embodiment of the present disclosure, the claw 221a is covered with the filler 3 provided in the through-hole 11b. However, the present disclosure is not limited to this example, and the claw 221a may be covered with a member different from the filler 3.

The claw 221a is provided on an axially lower side of a radially one end of at least one second blade 22. Accordingly, when the second impeller 2 is molded using a metal mold, it is possible to extract the metal mold in the axial direction. Accordingly, the impeller 100 is easily manufactured. In the example embodiment of the present disclosure, the claw 221a is provided on an axially lower side of the radially inner end of the second blade 22. Accordingly, compared to a case where the claw 221a is provided on an axially lower side of a radially outer end of the second blade 22, it is possible to prevent the claw 221a from jumping out to the radially outer side of the base 11. When the impeller 100 is assembled, the claw 221a does not easily interfere with other members, which facilitates an assembling operation. Moreover, the claw 221a is not limited to the example of the example embodiment of the present disclosure, and the claw 221a may be provided on the axially lower side of the radially outer end of the second blade 22.

The claw 221a is located radially inside the radially inner peripheral edge 21b of the shroud 21. When viewed in the axial direction, the claw 221a extends from the radially inner end of the second blade 22 to the central axis CA side in the direction in which the second blade 22 extends. Accordingly, when the second impeller 2 is molded using the metal mold, it is possible to extract the metal mold in the axial direction. Accordingly, the impeller 100 is easily manufactured. Moreover, when the second impeller 2 is connected to the first impeller 1, the first blade 12 adjacent to at least one second blade 22 does not easily come into contact with the claw 221a.

FIG. 7 is a cross-sectional view illustrating another configuration example of the fixing portion 221. As illustrated in FIG. 7, the fixing portion 221 has a thermal deformation portion 221b. A portion of the fixing portion 221 is thermally deformed, and thus, the thermal deformation portion 221b is defined. The thermal deformation portion 221b is in contact with the lower surface of the base 11. More specifically, for example, after the fixing portion 221 defined using a thermally deformable material such as a thermoplastic resin passes through the through-hole 11b, a distal end of the fixing portion 221 protruding outside the through-hole 11b is welded to the lower surface of the base 11. This welded portion becomes the thermal deformation portion 221b. Accordingly, when the impeller 100 is assembled, the second impeller 2 is able to be easily connected to the first impeller 1.

According to the above-described example embodiment of the present disclosure, the centrifugal fan 200 includes the impeller 100 which is rotatable about the central axis CA, and the motor 110 which drives the impeller 100.

According to the above-described example embodiment of the present disclosure, the impeller 100 which is rotatable about the central axis CA extending in the vertical direction includes the first impeller 1 and the second impeller 2 which is connected to the first impeller 1. The first impeller 1 has the base 11 and a plurality of first blades 12 which are arranged in the circumferential direction. The base 11 has the cup portion 111 of which the axially upper end is closed and the flange 112 which extends radially outward from the axially lower end of the cup portion 111. The second impeller 2 has the shroud 21 which has an annular or substantially annular shape about the central axis CA and faces the upper surface of the flange 112 in the axial direction, and the plurality of second blades 22 which are arranged in the circumferential direction. Each first blade 12 protrudes axially upward from the flange 112. Each second blade 22 protrudes axially downward from the shroud 21. In the circumferential direction, At least one second blade 22 is located between the first blades 12 adjacent to each other.

Accordingly, since, in the circumferential direction, at least one second blade 22 is located between the first blades 12 adjacent to each other, when the impeller 100 rotates, it is possible to efficiently send out the air radially outward from a portion radially inside the radially inner peripheral edge 21b of the annular shroud 21 via a portion between the shroud 21 and the base 11. In addition, the first blade 12 protrudes from the flange 112 facing the shroud 21. Thereby, a gap is not able to be defined between the first blade 12 and the flange 112. Accordingly, when the impeller 100 rotates, the air does not escape in the circumferential direction through the gap. Moreover, the second blade 22 protrudes from the shroud 21. Thereby, a gap is not able to be defined between the second blade 22 and the shroud 21. Accordingly, the first blades 12 and the second blades 22 are able to efficiently send out the air radially outward. Moreover, the impeller 100 is another member including the first impeller 1 and the second impeller 2. Accordingly, there is a possibility that the air may leak from a connection portion between the first blade 12 and the second blade 22. However, the gap is not able to be defined between the first blade 12 and the flange 112. Accordingly, even when the air leaks from the connection portion, it is possible to suppress an influence on a flow of the air sent out to the radially outer side of the impeller 100. Therefore, it is possible to improve the blowing efficiency of the impeller 100.

The impeller 100 includes the first impeller 1 and the second impeller 2. Accordingly, even when the base 11 of the first impeller 1 is configured to face the shroud 21 of the second impeller 2 in the axial direction, it is possible to mold the first impeller 1 and the second impeller 2 by extracting the metal molds in the vertical direction, respectively.

According to the above-described example embodiment of the present disclosure, the base 11 has the first groove 11a which is recessed axially downward. The first groove 11a is provided between the first blades 12 adjacent to each other and extends in the direction in which at least one second blade 22 extends. The axially lower end of at least one second blade 22 is located in the first groove 11a.

Accordingly, even in the case where a gap is defined between at least one second blade 22 and the base 11, it is possible to prevent the air from leaking from a portion between the second blade 22 and the base 11. Thereby, it is possible to suppress the decrease in efficiency which the air is sent to the radially outer side of the impeller 100 by at least one second blade 22.

According to the above-described example embodiment of the present disclosure, the base 11 has the through-hole 11b which penetrates the base 11 in the axial direction. At least one second blade 22 has the fixing portion 221 extending in the axial direction. The fixing portion 221 is fixed to the base 11 through the through-hole 11b.

Accordingly, the fixing portion 221 is fixed to the base 11, and thus, it is possible to easily connect the first impeller 1 and the second impeller 2, which are combined in the vertical direction, to each other.

According to the above-described example embodiment of the present disclosure, the fixing portion 221 may have the thermal deformation portion 221b in which a portion of the fixing portion 221 is thermally deformed. The thermal deformation portion 221b is in contact with the lower surface of the base 11.

Therefore, according to the structure in which the thermal deformation portion 221b is in contact with the lower surface of the base 11, it is possible to easily connect the second impeller 2 to the first impeller 1.

According to the above-described example embodiment of the present disclosure, the fixing portion 221 may have the claw 221a. The claw 221a is hooked to the lower surface of the base 11.

Therefore, according to the structure in which the claw 221a is hooked to the lower surface of the base 11, it is possible to easily connect the second impeller 2 to the first impeller 1.

According to the above-described example embodiment of the present disclosure, the claw 221a is provided on the axially lower side of the radially one end of at least one second blade 22.

Therefore, when the second impeller 2 is molded, it is possible to extract the metal mold in the axial direction.

According to the above-described example embodiment of the present disclosure, the claw 221a is provided on the axially lower side of the radially inner end of at least one second blade 22.

Accordingly, compared to the case where the claw 221a is provided on the axially lower side of the radially outer end of the second blade 22, the claw 221a does not easily interfere with other members when the impeller 100 is assembled.

According to the above-described example embodiment of the present disclosure, the claw 221a is located radially inside the radially inner peripheral edge 21b of the shroud 21.

Accordingly, when the second impeller 2 is molded using the metal mold, it is possible to extract the metal mold in the axial direction. Thereby, the impeller 100 is easily manufactured.

According to the above-described example embodiment of the present disclosure, when viewed in the axial direction, the claw 221a extends from the radially inner end of at least one second blade 22 to the central axis CA side in the direction in which at least one second blade 22 extends.

Accordingly, when the second impeller 2 is connected to the first impeller 1, the first blade 12 adjacent to at least one second blade 22 does not easily come into contact with the claw 221a.

According to the above-described example embodiment of the present disclosure, the upper surface of the claw 221a is in contact with the lower surface of the base 11. The axially lower end of the second blade 22 faces the bottom surface of the first groove 11a with a gap between the bottom surface of the first groove 11a and the axially lower end of the second blade 22.

Accordingly, it is possible to easily hook the claw 221a to the lower surface of the base 11. In addition, it is possible to prevent a gap from being generated between the upper surface of the claw 221a and the lower surface of the base 11. Therefore, it is possible to increase connection strength between the first impeller 1 and the second impeller 2. In addition, it is possible to effectively suppress or prevent occurrence of a gap between the second blade 22 and the flange 112.

According to the above-described example embodiment of the present disclosure, the impeller 100 further includes the filler 3 provided inside the through-hole 11b.

Accordingly, it is possible to prevent the air flowing between the first blades 12 from leaking in the axial direction through the through-hole 11b.

According to the above-described example embodiment of the present disclosure, the filler 3 covers at least a portion of the claw 221a outside the through-hole 11b.

Accordingly, at least a portion of the claw 221a is able to be fixed to the base 11 by the filler 3, and thus, it is possible to further increase the connection strength between the first impeller 1 and the second impeller 2.

According to the above-described example embodiment of the present disclosure, the shroud 21 has the second groove 21a which is recessed axially upward. The second groove 21a is provided between the second blades 22 adjacent to each other and extends in the direction in which at least one first blade 12 extends. The axially upper end of at least one first blade 12 is located in the second groove 21a.

Accordingly, even in a case where a gap is defined between at least one first blade 12 and the shroud 21, it is possible to prevent the air from leaking from a portion between the first blade 12 and the shroud 21. Therefore, it is possible to suppress the decrease in efficiency which the air is sent to the radially outer side of the impeller 100 by at least one first blade 12.

According to the above-described example embodiment of the present disclosure, the radially inner end of the second blade 22 is located radially outside the radially inner end of the first blade 12.

Accordingly, it is possible to prevent the gap between the radially inner ends of the first blades 12 from being too narrowed by the second blade 22. Accordingly, a flow of the air flowing into a portion between the first blades 12 is not able to be easily hindered by the second blade 22.

According to the above-described example embodiment of the present disclosure, the radially inner end of the second blade 22 is located radially outside a radially outer end of the cup portion 111.

Accordingly, when the second impeller 2 is connected to the first impeller 1, it is possible prevent the second blades 22 from abutting on the cup portion 111. Therefore, the connection operation of the first impeller 1 and the second impeller 2 is easily performed.

According to the above-described example embodiment of the present disclosure, when viewed in the axial direction, the length of the second blade 22 along the direction in which the second blade 22 extends is shorter than the length of the first blade 12 along the direction in which the first blade 12 extends.

Accordingly, when the second impeller 2 is connected to the first impeller 1, the second blade 22 does not easily abut on the cup portion 111. Therefore, a connection between the first impeller 1 and the second impeller 2 is easily performed.

For example, the example embodiment of the present disclosure is useful for an impeller of a blower which radially outward sends out the air taken into the blower.

Features of the above-described example embodiments and the modifications thereof may be combined appropriately as long as no conflict arises.

While example embodiments of the present disclosure have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present disclosure. The scope of the present disclosure, therefore, is to be determined solely by the following claims.

Claims

1-17. (canceled)

18: An impeller rotatable about a central axis extending in an axial direction, the impeller comprising: a first impeller; anda second impeller connected to the first impeller; whereinthe first impeller includes: a base; anda plurality of first blades arranged in a circumferential direction;the base includes: a cup portion including an axially upper end that is closed; anda flange extending radially outward from an axially lower end of the cup portion;the second impeller includes: a shroud with an annular or substantially annular shape about the central axis and opposing an upper surface of the flange in an axial direction; anda plurality of second blades arranged in the circumferential direction;each of the first blades protrudes axially upward from the flange;each of the second blades protrudes axially downward from the shroud; andin the circumferential direction, at least one second blade is located between the first blades adjacent to each other.

19: The impeller according to claim 18, wherein the base includes a first groove recessed axially downward;the first groove is between the first blades adjacent to each other and extends in a direction in which the at least one second blade extends; andan axially lower end of the at least one second blade is located in the first groove.

20: The impeller according to claim 18, wherein the base includes a through-hole penetrating the base in the axial direction;the at least one second blade includes a fixing portion extending in the axial direction; andthe fixing portion is fixed to the base through the through-hole.

21: The impeller according to 20, wherein a fixing portion includes a thermal deformation portion in which a portion of the fixing portion is thermally deformed; andthe thermal deformation portion is in contact with a lower surface of the base.

22: The impeller according to claim 20, wherein the fixing portion includes a claw; andthe claw is hooked to a lower surface of the base.

23: The impeller according to claim 22, wherein the claw is provided on an axially lower side of a radial end of the at least one second blade.

24: The impeller according to claim 23, wherein the claw is provided on an axially lower side of a radially inner end of the at least one second blade.

25: The impeller according to claim 23, wherein the claw is located radially inside of a radially inner peripheral edge of the shroud.

26: The impeller according to claim 25, wherein when viewed in the axial direction, the claw extends from the radially inner end of the at least one second blade to the central axis side in a direction in which the at least one second blade extends.

27: The impeller according to claim 19, wherein an upper surface of the claw is in contact with the lower surface of the base; andthe axially lower end of the second blade opposes a bottom surface of the first groove with a gap therebetween.

28: The impeller according to claim 23, wherein the impeller further includes a filler inside the through-hole.

29: The impeller according to claim 28, wherein the filler covers at least a portion of the claw outside the through-hole.

30: The impeller according to claim 18, wherein the shroud includes a second groove recessed axially upward;the second groove is provided between two of the second blades adjacent to each other and extends in a direction in which the at least one first blade extends; andan axially upper end of the at least one first blade is located in the second groove.

31: The impeller according to claim 18, wherein a radially inner end of the second blade is located radially outside a radially inner end of the first blade.

32: The impeller according to claim 18, wherein a radially inner end of the second blade is located radially outside a radially outer end of the cup portion.

33: The impeller according to claim 18, wherein when viewed in the axial direction, a length of the second blade along a direction in which the second blade extends is shorter than a length of the first blade along a direction in which the first blade extends.

34: A blower comprising: the impeller according to claim 18 that is rotatable about the central axis; anda motor to drive the impeller.