CN108700084B

CN108700084B - Air supply device and dust collector

Info

Publication number: CN108700084B
Application number: CN201780013657.3A
Authority: CN
Inventors: 吉野慎吾; 早光亮介; 岸荣
Original assignee: Nidec Corp
Current assignee: Nidec Corp
Priority date: 2016-04-11
Filing date: 2017-04-07
Publication date: 2020-07-14
Anticipated expiration: 2037-04-07
Also published as: US20190290081A1; EP3444480A4; CN108700084A; WO2017179498A1; EP3444480A1; JPWO2017179498A1

Abstract

An air supply device includes: an impeller rotatable about a central axis extending in an up-down direction; a motor located at a lower side of the impeller and rotating the impeller; and a duct that houses the impeller, the duct having an airflow path in an internal space thereof, a suction port that causes a fluid to flow into the internal space, and a discharge port that discharges the fluid from the internal space, the impeller including: a plurality of blades arranged in a circumferential direction; an annular shroud that connects upper portions of the plurality of blades and has an opening at a position axially opposite to the suction port; and a base plate that connects lower portions of the plurality of blades and expands in a radial direction, wherein the duct has a cover portion that covers at least a part of the blades and an upper portion of the shroud, an inner diameter of the shroud is equal to or larger than an outer diameter of the base plate, and the cover portion has a first convex portion that protrudes from a lower surface of the cover portion toward an axially lower side and is disposed radially inward of an inner peripheral surface of the shroud.

Description

Air supply device and dust collector

Technical Field

The invention relates to a blower and a dust collector.

Background

A conventional air blowing device is disclosed in japanese laid-open patent publication No. 2002-156128. The turbofan disclosed in japanese laid-open patent publication No. 2002-156128 includes a housing, a motor, a base plate, a blade, and a shroud. The base plate, the blades, and the shroud are housed within a housing. A plurality of blades are arranged in the circumferential direction. The shroud joins the ends of the plurality of blades. A plurality of blades are arranged on the periphery of the base plate.

The casing has a suction side end portion, a straight portion, and an inclined step portion. The inner diameter of the suction side end is formed to be the same as or larger than the outer diameter of the substrate.

The air is discharged from the center portion of the turbofan in an outer circumferential direction. Further, since the shroud has the above-described feature, it is claimed that the noise of the turbofan can be reduced.

However, according to the turbofan disclosed in japanese laid-open patent publication No. 2002-156128, a part of the air discharged to the radial outside of the blade flows back to the radial inside from the gap between the shroud and the casing. In this case, there is a problem that turbulence occurs in the airflow passage inside the casing or air resistance is generated by the reverse airflow, thereby lowering the air blowing efficiency of the air blower.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a blower capable of suppressing occurrence of turbulence in an airflow path of a duct or reverse flow of an airflow radially inward, and improving blowing efficiency. Another object of the present invention is to provide a vacuum cleaner having an air blowing device capable of improving air blowing efficiency.

An air blowing device according to an exemplary embodiment of the present invention includes: an impeller rotatable about a central axis extending in an up-down direction; a motor part located at a lower side of the impeller to rotate the impeller around a central axis; and a duct that houses the impeller, the duct having an airflow passage, a suction port that causes a fluid to flow into the internal space, and a discharge port that discharges the fluid from the internal space in the internal space. The impeller has: a plurality of blades arranged in a circumferential direction; an annular shroud that connects upper portions of the plurality of blades and has an opening at a position axially opposite to the suction port; and a base plate which connects lower portions of the plurality of blades and expands in a radial direction. The duct has a shroud portion covering at least a portion of the blades and above the shroud. The inner diameter of the shield is larger than or equal to the outer diameter of the substrate. The cover portion has a first convex portion that protrudes from a lower surface of the cover portion toward an axially lower side and is disposed radially inward of an inner circumferential surface of the shroud.

According to an exemplary embodiment of the present invention, an air blowing device capable of improving air blowing efficiency can be provided. Further, according to an exemplary embodiment of the present invention, a vacuum cleaner having such a blower device can be provided.

The above and other features, elements, steps, features and advantages of the present invention will be more clearly understood from the following detailed description of preferred embodiments of the present invention with reference to the accompanying drawings.

Drawings

Fig. 1 is a sectional view of a cleaning robot according to an embodiment of the present invention.

Fig. 2 is a perspective view of the air blowing device according to the embodiment of the present invention.

Fig. 3 is a longitudinal sectional view of the blower according to the embodiment of the present invention.

Fig. 4 is a perspective view of the impeller according to the embodiment of the present invention as viewed from above.

Fig. 5 is a plan view of an impeller according to an embodiment of the present invention.

Fig. 6 is a side cross-sectional view of an impeller according to an embodiment of the present invention.

Fig. 7 is an enlarged longitudinal sectional view of a part of the blower according to the embodiment of the present invention.

Fig. 8 is an enlarged longitudinal sectional view of a part of the blower according to the embodiment of the present invention.

Fig. 9 is an enlarged vertical sectional view of a part of a blower according to a modification of the embodiment of the present invention.

Fig. 10 is an enlarged vertical cross-sectional view showing the vicinity of a shroud of a blower according to a modification of the embodiment of the present invention.

Fig. 11 is an enlarged vertical cross-sectional view showing the vicinity of a shroud of a blower according to a modification of the embodiment of the present invention.

Detailed Description

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, the extending direction of the central axis a of the air blowing device 1 shown in fig. 3 is simply referred to as "axial direction", and the radial direction and the circumferential direction around the central axis a of the air blowing device 1 are simply referred to as "radial direction" and "circumferential direction". Similarly, the direction in which the impeller 20 shown in fig. 4 to 6 coincides with the axial direction, the radial direction, and the circumferential direction of the air blowing device 1 in the state of being incorporated into the air blowing device 1 will be simply referred to as "axial direction", "radial direction", and "circumferential direction". The vertical direction is a name for explanation only, and does not limit the actual positional relationship and direction.

An air blowing device according to an exemplary embodiment of the present invention will be described. Fig. 1 is a cross-sectional view of a cleaning robot 100 according to an exemplary embodiment of the present invention, and as shown in fig. 1, an air blowing device 1 is mounted on the cleaning robot (cleaner) 100 and used as a suction member.

The cleaning robot 100 performs cleaning on the floor surface F by sucking air containing dust on the floor surface F and discharging the air from which the dust is removed while self-traveling on the floor surface F at the installation position. The cleaning robot 100 includes a suction passage 104, a dust collection container 105, a filter unit 106, an exhaust passage 107, and the blower 1 in a disc-shaped housing 101. A drive wheel 109 and a front wheel 110 are provided on the lower surface of the housing 101.

The casing 101 has an air inlet 103 in the center of the lower surface and an air outlet 108 in the side surface. By driving the blower device 1, the cleaning robot 100 sucks air containing dust on the floor surface F from the air inlet 103 while walking. Air containing dust sucked into the housing 101 through the suction port 103 flows into the dust collection container 105 through the suction passage 104. The airflow flowing into the dust collection container 105 passes through the filter unit 106 and is sucked into the air blower 1 through the exhaust passage 107. The air sucked into the air blower 1 is discharged obliquely upward rearward from the air outlet 108. At this time, the dust contained in the air flow in the dust collection container 105 is captured by the filter unit 106, and the dust D is accumulated in the dust collection container 105.

Fig. 2 is a perspective view of the air blowing device 1 according to the embodiment of the present invention. Fig. 3 is a vertical cross-sectional view of the blower device 1 according to the embodiment of the present invention. As shown in fig. 2 and 3, the blower 1 includes an impeller 20, a motor unit 30, and a duct 10. The impeller 20 is accommodated in the inner space of the duct 10. The motor unit 30 is located below the impeller 20 and rotates the impeller 20 about the central axis a.

The impeller 20 is coupled to a shaft (not shown) extending in the axial direction from the motor unit 30, and is supported to be rotatable about the central axis a. That is, the impeller 20 is rotatable about a central axis a extending in the vertical direction. The control board 40 is disposed axially below the motor unit 30, and controls the motor unit 30.

Duct 10 has an airflow passage 13, a suction port 11 for allowing a fluid to flow into the internal space, and a discharge port 12 for discharging the fluid from the internal space, and duct 10 accommodates impeller 20. The duct 10 is composed of a cover 14, a peripheral wall 15, and a motor case 16, and an airflow passage 13 is formed in an internal space surrounded by these components. In more detail, the duct 10 has a shroud portion 14 covering at least a part of the blades 23 and above the shroud 22. The cover 14 covers the upper side of the impeller 20 and is formed in an annular shape when viewed in a plane in the axial direction. The outer diameter of the cover portion 14 is larger than the outer diameter of the impeller 20. In the present embodiment, the duct 10 is configured by a member including the cover portion 14 and a part of the peripheral wall portion 15, and a member including a part of the peripheral wall portion 15 and the motor case 16. This enables the two members to be molded as separate resin members, and therefore, the duct 10 can be formed at low cost.

A cylindrical portion 14a having a cylindrical shape extending upward in the axial direction is provided at the center of the cover portion 14. The cylindrical portion 14a is formed with a circular suction port 11 when viewed in a plane in the axial direction. The suction port 11 is disposed axially opposite an opening 22a of a shroud 22 described later, and gas (fluid) flows from the outside into the internal space of the duct 10 through the suction port 11.

The peripheral wall portion 15 covers the impeller 20 from the side, and is formed in a cylindrical shape extending axially downward from the outer peripheral edge of the cover portion 14. A mouth portion 15a extending radially outward is provided in the peripheral wall portion 15, and a discharge port 12 for discharging gas (fluid) from the internal space of the duct 10 is formed in the mouth portion 15 a.

The motor housing 16 is located axially below the impeller 20. More specifically, blower device 1 further includes motor case 16 positioned below substrate 21, which will be described later. The upper surface of the motor case 16 is radially expanded, and extends to the lower end of the peripheral wall portion 15 to be coupled to the peripheral wall portion 15. The circumferential surface of the motor case 16 is formed in a cylindrical shape extending axially downward from the outer circumferential edge of the circumferential wall 15, and the motor unit 30 and the control board 40 are accommodated in the motor case 16.

An annular recess 16a recessed downward is formed on the upper surface of the motor case 16 at a position radially outward of the impeller 20. Between suction port 11 and discharge port 12, peripheral wall 15, concave portion 16a, and cover 14 form airflow path 13 including an annular region radially outside impeller 20.

Fig. 4 is a perspective view of the impeller 20 according to the embodiment of the present invention as viewed from above, and fig. 5 is a plan view of the impeller 20 according to the embodiment of the present invention. Fig. 6 is a side cross-sectional view of the impeller 20 according to the embodiment of the present invention.

As shown in fig. 4 to 6, the impeller 20 includes a plurality of blades 23, an annular shroud 22, and a base plate 21. The blades 23 are present between the base plate 21 and the shroud 22. The plurality of blades 23 are arranged in the circumferential direction.

The shroud 22 is annular, connects upper portions of the plurality of blades 23, and has an opening 22a at a position axially facing the suction port 11. More specifically, the shroud 22 is formed in an annular shape by connecting upper portions of the plurality of blades 23, and an opening 22a for sucking gas is formed in a central portion of the shroud 22. The opening 22a is circular when viewed from a plane in the axial direction.

The base plate 21 connects lower portions of the plurality of blades 23 and expands in the radial direction. The substrate 21 is formed in a disc shape. The substrate 21 has a substrate protrusion 21a protruding downward from the lower surface of the substrate 21. More specifically, the substrate protrusion 21a protrudes from the outer edge of the lower surface of the substrate 21 in the radial direction, and is formed in an annular shape (see fig. 6).

The vane 23 includes first and

second vanes

23a, 23b having different radial lengths, and the first and

second vanes

23a, 23b are alternately arranged in the circumferential direction. The first blade 23a and the second blade 23b are plate-like members that stand in the axial direction and extend outward from the inside in the radial direction. The radially inner end of the first vane 23a is located radially inward of the radially inner end of the second vane 23b, and the first vane 23a is radially longer than the second vane 23 b.

The first blade 23a and the second blade 23b are curved as follows (see fig. 5): when the impeller 20 is rotated counterclockwise as viewed from the plane on the upper side in the axial direction, the radially outer end is inclined to the rear side in the rotational direction with respect to the radially inner end, and the rear side in the rotational direction is concave. The interval between the first vane 23a and the second vane 23b is enlarged toward the radially outer side.

The radially outer end 24a of the first blade 23a and the radially outer end 24b of the second blade 23b extend radially outward beyond the outer peripheral edge of the base plate 21 (see fig. 4). In other words, the radially outer ends 24a and 24b of the vane 23 extend radially outward from the outer peripheral edge of the base plate 21. The radially inner ends of the first vane 23a and the second vane 23b extend radially inward of the suction port 11 (see fig. 3). That is, the radially inner end of the vane 23 extends radially inward of the suction port 11. This enables the blades 23 to be formed radially large, and the air volume generated by the rotation of the impeller 20 can be increased. The outer peripheral edge of the substrate 21 may have other shapes, and may be partially cut radially inward from a circumferential outer edge, for example.

The upper ends of the first blade 23a and the second blade 23b have

protrusions

25a and 25b that protrude upward in the axial direction (see fig. 6). The

projections

25a and 25b are positioned radially inward of the opening 22a, are arranged on the same circle, and project upward from the upper end of the shroud 22.

The upper ends of the first blade 23a and the second blade 23b include:

inclined surfaces

26a, 26b which are lowered from the protruding

portions

25a, 25b toward the inner side in the radial direction; and

inclined surfaces

27a and 27b which are lowered from the

projections

25a and 25b to the outside in the radial direction.

Further, the

inclined surfaces

27a and 27b have projecting

portions

28a and 28b formed at positions radially outward of the opening 22a of the shroud 22 and projecting upward in the axial direction. The upper ends of the

projections

28a and 28b extend to the lower surface of the shield 22 and are coupled to the shield 22. That is, the blade 23 has

protrusions

28a and 28b protruding axially upward at positions radially outward of the first convex portion 17 (see fig. 7) described later. This allows the blades 23 to be formed to be axially large on the radially outer side of the opening 22a, and the amount of air generated by the rotation of the impeller 20 can be increased.

The base plate 21, the shroud 22, and the blades 23 are formed of resin moldings of the same material, and the inner diameter D2 of the shroud 22 is formed to be the same size as the outer diameter D1 of the base plate 21 (see fig. 6).

Thus, when the impeller 20 spanning the base plate 21 and the shroud 22 is formed, the upper and lower molds are prevented from interfering with each other and can be withdrawn upward and downward in the axial direction. Therefore, the impeller 20 can be integrally molded by the mold, and mass productivity of the impeller 20 can be improved. Even when the inner diameter D2 of the shroud 22 is larger than the outer diameter D1 of the base plate 21, the impeller 20 can be integrally molded by a mold.

Fig. 7 and 8 are vertical sectional views showing a part of the blower device 1 according to the embodiment of the present invention in an enlarged manner, and show the relationship between the duct 10 and the impeller 20. As shown in fig. 7, the shield 22 has an inner peripheral surface 22b constituting the opening 22 a. The cover 14 has a first convex portion 17, and the first convex portion 17 is arranged radially inward of the inner circumferential surface 22b of the shroud 22, and protrudes axially downward from the lower surface of the cover 14. The outer peripheral surface of the first convex portion 17 radially faces the inner peripheral surface 22b of the shroud 22. The outer peripheral surface of the first convex portion 17 and the inner peripheral surface 22b of the shroud 22 do not necessarily have to face each other circumferentially. That is, the outer peripheral surface of the first convex portion 17 may radially face the inner peripheral surface 22b of the shroud 22. The shapes of the outer peripheral surface of the first projecting portion 17 and the inner peripheral surface 22b of the shroud 22 described herein are not limited to the peripheral surfaces. For example, the outer peripheral surface of the first convex portion 17 and the inner peripheral surface 22b of the shield 22 may have projections and depressions formed in a part of the peripheral surfaces.

The first convex portion 17 blocks the flow path of the air R1 flowing back radially inward from the gap between the shroud 22 and the cover portion 14. Therefore, a part of the air blown radially outward of impeller 20 can be suppressed from flowing backward through the gap between shroud 22 and cover 14. Therefore, it is possible to prevent the air blowing efficiency from being lowered due to air resistance caused by air having turbulence or backflow in the airflow passage 13. Further, a radial gap between the outer peripheral surface of the first convex portion 17 and the inner peripheral surface 22b of the shroud 22 is narrower than an axial gap between the shroud 22 and the cover portion 14. Therefore, the flow of the air R1 flowing back radially inward from the gap between the shroud 22 and the cover 14 can be blocked.

The radially outer end of the first projection 17 has a lower end extending to a position where the axial height is substantially equal to the height of the lower end of the inner peripheral surface 22b of the shroud 22, or axially downward. Accordingly, the air flowing radially outward along the lower surface of the cover 14 is smoothly guided from the lower end of the first projection 17 to the lower end of the inner circumferential surface 22b of the shroud 22, and is blown radially outward of the impeller 20 through the lower surface of the shroud 22. Therefore, the air blowing efficiency of the air blowing device 1 can be further improved. That is, since the collision of the circulating air with the inner peripheral surface 22b of the shroud 22 can be reduced, the circulating air can be efficiently blown out radially outward.

As shown in fig. 8, the projection 28a of the first blade 23a and the projection 28b of the second blade 23b (not shown in fig. 7, see fig. 4) are connected to the lower surface of the shroud 22 at positions radially outward of the first convex portion 17, and the first convex portion 17 faces the

inclined surfaces

27a, 27b in the vertical direction, therefore, when the region of the first blade 23a and the second blade 23b radially outward of the first convex portion 17 is defined as a blade first region L1 and the region vertically facing the first convex portion 17 is defined as a blade second region L2, the blade first region L1 is located above the upper end of the radially outer end of the blade second region L2 with respect to the upper ends of the first blade 23a and the second blade 23 b.

That is, the vane 23 has the vane first region L1 located radially outward of the first protrusion 17 and the vane second region L2 facing the first protrusion 17 in the vertical direction, and the upper end of the vane first region L1 is located upward of the upper end of the radially outer end of the vane second region L2, and therefore, even when the impeller 20 vibrates in the vertical direction during rotation, the first vane 23a and the second vane 23b can be prevented from coming into contact with the first protrusion 17.

Returning to fig. 7, an annular groove portion 16b is provided on the upper surface of the motor case 16, and the groove portion 16b axially faces a substrate protruding portion 21a protruding from the outer peripheral end of the lower surface of the substrate 21. The radial width of the groove portion 16b is larger than the radial width of the substrate protrusion portion 21 a. Thus, by disposing the substrate protruding portion 21a and the groove portion 16b close to each other, the axial gap between the lower surface of the substrate 21 and the upper surface of the motor case 16 can be reduced.

This can suppress a part of the air blown radially outward of the impeller 20 from flowing backward through the gap between the lower surface of the base plate 21 and the upper surface of the motor case 16, and can prevent a reduction in air blowing efficiency due to air resistance caused by the air having turbulence or flowing backward in the airflow passage 13.

Further, an axial gap between the lower end of the base plate protruding portion 21a and the upper surface of the motor case 16 is narrower than an axial gap between the lower surface of the base plate 21 and the upper surface of the motor case 16. Therefore, a part of the air blown radially outward of the impeller 20 can be further suppressed from flowing into the gap between the lower surface of the base plate 21 and the upper surface of the motor case 16 and flowing backward radially inward.

The substrate protrusion 21a may be formed at a position other than the outer edge of the substrate 21 in the radial direction. For example, the substrate protrusion 21a may be formed on the lower surface of the substrate 21 at a position inward of the radially outer edge. Even in this case, a part of the air blown radially outward of the impeller 20 can be prevented from flowing back radially inward into the gap between the lower surface of the base plate 21 and the upper surface of the motor case 16 as the air R2.

When the motor unit 30 is driven, the impeller 20 rotates about the central axis a. Thereby, air is sucked into the duct 10 through the suction port 11. The air sucked into the duct 10 is accelerated radially outward by the impeller 20. The air accelerated radially outward passes between the shroud 22 and the base plate 21, and is blown radially outward of the impeller 20. The air blown out radially outward of the impeller 20 is discharged from the air outlet 12 to the outside of the duct 10 through the airflow passage 13 formed circumferentially inside the duct 10.

Fig. 9 is an enlarged vertical sectional view showing a part of a modification of the blower device 1 according to the exemplary embodiment of the present invention. A second protrusion 18 protruding downward in the axial direction may be provided on the lower surface of cover 14. The inner peripheral surface of the second projection 18 radially faces the outer peripheral surface of the shroud 22.

Second lobe 18 blocks airflow into the gap between shroud 22 and hood 14. Therefore, a part of the air blown radially outward of the impeller 20 can be prevented from flowing into the gap between the shroud 22 and the cover 14, and the occurrence of turbulence or backflow in the airflow passage 13 can be further suppressed. Although both the first projection 17 and the second projection 18 may be provided, even if only one of them is provided, it is possible to prevent a reduction in air blowing efficiency due to air resistance caused by air that is turbulent or flowing backward in the airflow passage 13. Further, a radial gap between the inner circumferential surface of the second convex portion 18 and the outer circumferential surface of the shroud 22 is narrower than an axial gap between the shroud 22 and the cover portion 14. Therefore, the air flowing backward in the radial direction from the gap between shroud 22 and cover 14 can be blocked.

Fig. 10 is an enlarged vertical cross-sectional view of the vicinity of the shroud 22 of the blower 1 according to the modified example of the exemplary embodiment of the present invention. The inner peripheral surface 22b of the shroud 22 has a first inner peripheral surface 221 and a second inner peripheral surface 222, and the first inner peripheral surface 221 is disposed axially above the second inner peripheral surface 222. The first inner peripheral surface 221 is formed parallel to the axial direction, and the second inner peripheral surface 222 is formed with: inclined with respect to the axial direction so as to be farther from the center axis a toward the axially lower side, and curved convexly toward the radially inner side. The first inner peripheral surface 221 and the second inner peripheral surface 222 are connected by a curved portion 223 that is curved convexly inward in the radial direction. That is, the lower end of the first inner circumferential surface 221 and the upper end of the second inner circumferential surface 222 are smoothly connected.

That is, the radial gap between the outer peripheral surface of the first projecting portion 17 and the inner peripheral surface 22b of the shroud 22 is formed wider on the lower side in the axial direction than on the upper side in the axial direction.

Therefore, even when the impeller 20 vibrates in the vertical direction during rotation and the lower end of the inner circumferential surface 22b of the shroud 22 is lowered axially downward than the lower end of the radially outer end of the first protrusion 17, air flowing radially outward along the lower surface of the cover portion 14 can be smoothly guided radially outward along the second inner circumferential surface 222 from the lower end of the first protrusion 17. Therefore, even when the impeller 20 vibrates in the vertical direction during rotation, a decrease in the air blowing efficiency of the air blowing device 1 can be suppressed.

Further, the first inner peripheral surface 221 and the second inner peripheral surface 222 are connected by the curved portion 223 curved convexly toward the radial inner side, and the second inner peripheral surface 222 is formed curved convexly toward the radial inner side, whereby the air flowing along the inner peripheral surface 22b of the shroud 22 can be smoothly guided to the radial outer side. This can further suppress a decrease in air blowing efficiency of the air blowing device 1. Here, the expression that the first inner circumferential surface 221 is connected to the second inner circumferential surface 222 by the curved portion 223 means that the lower end of the first inner circumferential surface 221 is smoothly connected to the upper end of the second inner circumferential surface 222.

Further, since the first inner peripheral surface 221 formed parallel to the axial direction ensures a thickness of the shield 22 in the vertical direction with a predetermined width from the upper end of the inner peripheral surface 22b, a decrease in rigidity of the shield 22 can be suppressed.

Fig. 11 is an enlarged vertical sectional view showing the vicinity of the shroud 22 of the blower 1 according to the modification of the exemplary embodiment of the present invention, and as shown in fig. 11, a surface parallel to the axial direction may be omitted from the inner circumferential surface 22b of the shroud 22. In this case, the entire inner peripheral surface 22b is constituted by the second inner peripheral surface 222. With this configuration, even when the impeller 20 vibrates in the vertical direction during rotation, a decrease in the air blowing efficiency of the air blowing device 1 can be further suppressed.

In fig. 10 and 11, the second inner peripheral surface 222 is formed to be convexly curved toward the radially inner side, but the second inner peripheral surface 222 may be formed by a conical surface that is not curved and is inclined with respect to the axial direction so as to be farther from the central axis a toward the axially lower side.

According to the present embodiment, the inner diameter of the shroud 22 is formed to be equal to or larger than the outer diameter of the substrate 21, so that the upper and lower molds can be withdrawn upward and downward in the axial direction while preventing the mutual interference between the molds. Therefore, the impeller 20 can be integrally molded by the mold, and mass productivity can be improved.

The first convex portion 17 protrudes axially downward from the lower surface of the cover portion 14, and the first convex portion 17 is disposed radially inward of the inner circumferential surface of the shroud 22. Thus, the first convex portion 17 blocks the flow path of the air flowing into the gap between the shroud 22 and the cover portion 14 and flowing backward radially inward. Therefore, a part of the air blown radially outward of the impeller 20 can be suppressed from flowing into the gap between the shroud 22 and the cover 14, and a reduction in air blowing efficiency due to air resistance caused by air having turbulence or backflow in the airflow passage 13 can be prevented.

The outer peripheral surface of the first convex portion 17 radially faces the inner peripheral surface of the shroud 22. Accordingly, the first convex portion 17 closes the radially inner side of the gap between the shroud 22 and the cover portion 14, and thus the air flow efficiency can be further prevented from being lowered due to air resistance caused by air having turbulence or backflow in the air flow passage 13. In the present embodiment, the radial gap between the outer peripheral surface of the first projecting portion 17 and the inner peripheral surface of the shroud 22 is fixed in the axial direction. However, the radial gap between the outer peripheral surface of the first projecting portion 17 and the inner peripheral surface of the shroud 22 may not be fixed in the axial direction. For example, at least one of the outer peripheral surface of the first convex portion 17 and the inner peripheral surface of the shield 22 may be curved.

By providing the second convex portion 18 that protrudes axially downward from the lower surface of the cover portion 14 and faces the outer peripheral surface of the shroud 22, the second convex portion 18 blocks the airflow from flowing into the gap between the shroud 22 and the cover portion 14. Therefore, a part of the air blown radially outward of the impeller 20 can be suppressed from flowing into the gap between the shroud 22 and the cover 14, and a reduction in air blowing efficiency due to air resistance caused by air having turbulence or backflow in the airflow passage 13 can be prevented.

When the region of the vane 23 radially outward of the first projection 17 is a first vane region and the region facing the first projection 17 in the vertical direction is a second vane region, the first vane region is located above the upper end of the radially outer end of the second vane region with respect to the upper end of the vane 23. Therefore, even when the impeller 20 vibrates in the vertical direction during rotation, the upper ends of the blades 23 can be prevented from contacting the first convex portions 17. Further, the blades 23 can be formed to be axially large at a position radially outward of the first convex portion 17, and the air volume generated by the rotation of the impeller 20 can be increased.

The lower end of the inner peripheral surface 22b of the shroud 22 is substantially equal in axial height to the lower end of the radially outer end of the first projection 17. Accordingly, the air flowing radially outward along the lower surface of the cover 14 is smoothly guided from the lower end of the first projection 17 to the lower end of the inner circumferential surface 22b of the shroud 22, and is blown radially outward of the impeller 20 by the lower surface of the shroud 22. Therefore, air resistance due to the first convex portion 17 can be reduced, and air blowing efficiency can be further improved.

The lower end of the inner peripheral surface 22b of the shroud 22 may be positioned axially above the lower end of the radially outer end of the first projecting portion 17. Even in this case, since the air flowing radially outward along the lower surface of the cover portion 14 is smoothly guided from the lower end of the first convex portion 17 to the lower end of the inner circumferential surface 22b of the shroud 22, the air blowing efficiency of the air blower 1 can be improved. Further, in this configuration, since the radial gap between the inner peripheral surface 22b of the shroud 22 and the radially outer end of the first projecting portion 17 can be reduced, a part of the air blown radially outward of the impeller 20 can be suppressed from flowing backward from the gap between the shroud 22 and the cover 14.

Further, since the radially outer end of the vane 23 extends radially outward from the outer peripheral edge of the base plate 21 and the radially inner end of the vane 23 extends radially inward from the suction port 11, the vane 23 can be formed radially large, and the air volume generated by the rotation of the impeller 20 can be increased.

Also, since the axial gap between the lower end of the base plate protruding portion 21a and the upper surface of the motor case 16 is narrower than the axial gap between the lower surface of the base plate 21 and the upper surface of the motor case 16, the base plate protruding portion 21a blocks the airflow from flowing into the axial gap between the lower surface of the base plate 21 and the upper surface of the motor case 16. Therefore, a part of the air blown radially outward of the impeller 20 can be suppressed from flowing into the gap between the lower surface of the base plate 21 and the upper surface of the motor case 16, and a drop in air blowing efficiency due to air resistance caused by the air having a turbulent flow or a reverse flow in the airflow passage 13 can be prevented.

The substrate protrusion 21a is located on the outer edge of the substrate 21 in the radial direction. A groove portion 16b is provided on the upper surface of the motor case 16 so as to vertically face the substrate protruding portion 21 a. The groove portion 16b is formed to have a radial width larger than that of the substrate protrusion portion 21 a. That is, a groove portion 16b having a radial width larger than that of the substrate protruding portion 21a is formed on the upper surface of the motor case 16 so as to face the substrate protruding portion 21a in the vertical direction. Therefore, the axial gap between the lower surface of the substrate 21 and the upper surface of the motor case 16 can be further reduced by disposing the substrate protruding portion 21a and the groove portion 16b close to each other. Therefore, the flow into the gap between the lower surface of the base plate 21 and the upper surface of the motor case 16 can be further suppressed.

The embodiments and modifications described above are merely illustrative of the present invention. The configurations of the embodiment and the modification may be appropriately changed within a range not departing from the technical spirit of the present invention. The embodiment and the plurality of modifications may be combined and implemented within a possible range.

As shown in fig. 1, the air blowing device 1 of the present invention is mounted on a cleaning robot 100. The blower device 1 may be mounted not only on the cleaning robot 100 but also on a vacuum cleaner such as a portable cleaner. Thus, a vacuum cleaner with high air blowing efficiency can be realized. The present invention may be mounted on a device other than a vacuum cleaner. For example, the air blowing device 1 of the present invention may be mounted on an electronic device such as a computer for internal cooling. The blower 1 of the present invention may be mounted on various other OA equipment, medical equipment, home electric appliances, or transportation equipment.

The detailed structure of the blower 1 may be different from the above-described embodiment and modifications. Further, the respective elements appearing in the above-described embodiment and the modified examples may be appropriately combined within a range in which no contradiction occurs.

The air blowing device with high air blowing efficiency is suitable for a dust collector, for example. The air blowing device of the present invention can also be used in other electronic devices.

Claims

1. An air supply device includes:

an impeller rotatable about a central axis extending in an up-down direction;

a motor part located at a lower side of the impeller to rotate the impeller around a central axis; and

a duct that houses the impeller, the duct having an airflow passage, a suction port that flows a fluid into the internal space, and a discharge port that discharges the fluid from the internal space in an internal space,

the impeller has:

a plurality of blades arranged in a circumferential direction;

an annular shroud that connects upper portions of the plurality of blades and has an opening at a position axially opposite to the suction port; and

a base plate connecting lower portions of the plurality of blades and expanding in a radial direction,

the duct has a shroud portion covering at least a portion of the blades and above the shroud,

the air supply device is characterized in that,

the inner diameter of the shield is larger than or equal to the outer diameter of the substrate,

the cover portion has a first convex portion that protrudes from a lower surface of the cover portion toward an axially lower side and is disposed radially inward of an inner circumferential surface of the shroud,

the lower end of the radially outer end of the first projection extends to a position where the height in the axial direction is the same as the height of the lower end of the inner peripheral surface of the shroud or a position axially below the lower end,

the inner peripheral surface of the shield has a first inner peripheral surface and a second inner peripheral surface,

the first inner peripheral surface is arranged axially above the second inner peripheral surface,

the second inner peripheral surface is inclined with respect to the axial direction so as to be farther from the central axis toward an axially lower side.

2. The air supply arrangement according to claim 1,

an outer peripheral surface of the first convex portion is radially opposed to an inner peripheral surface of the shroud.

3. The air supply arrangement of claim 2,

a radial gap between an outer peripheral surface of the first convex portion and an inner peripheral surface of the shroud is wider on an axially lower side than on an axially upper side.

4. The air supply device according to any one of claims 1 to 3,

the blade has:

a first vane region located radially outward of the first projection; and

a second blade region that is opposed to the first projection in the vertical direction,

the upper end of the first region of the vane is located above the upper end of the radially outer end of the second region of the vane.

5. The air supply device according to any one of claims 1 to 3,

the blade has a protruding portion protruding axially upward at a position radially outward of the first convex portion.

6. The air supply device according to any one of claims 1 to 3,

the radially outer end of the blade extends radially outward beyond the outer peripheral edge of the base plate.

7. The air supply device according to any one of claims 1 to 3,

the radially inner end of the vane extends radially inward of the suction port.

8. The air supply device according to any one of claims 1 to 3,

the blower device also has a motor housing located on the underside of the base plate,

the substrate has a substrate protruding portion protruding from a lower surface of the substrate toward a lower side,

an axial gap between a lower end of the base plate protrusion and an upper surface of the motor case is narrower than an axial gap between a lower surface of the base plate and an upper surface of the motor case.

9. The air supply arrangement of claim 8,

the base plate protrusion is located at a radially outer edge of the base plate,

a groove portion that is opposed to the substrate protrusion portion in the up-down direction and has a radial width larger than that of the substrate protrusion portion is formed on an upper surface of the motor case.

10. A dust collector is characterized in that a dust collector is provided,

the vacuum cleaner has the air blowing device of any one of claims 1 to 9.