Blower and cleaner

Abstract

To improve performance of a blower having an impeller in which a shroud is disposed.SOLUTION: An impeller 1 of a blower 100 may rotate around a rotation axis J extending in an axial direction with a shaft 21 of a motor 2. A hub 11 of the impeller has a cone shape in which an outer diameter becomes smaller toward one side in the axial direction. A plurality of blades 12 extends from a radial outer surface of the hub to the radial outer side and is arranged in a circumferential direction and extends in at least the axial direction along the radial outer surface of the hub. A cylindrical shroud 13 encloses a portion at one side in the axial direction of each blade and the rotation axis and is connected to a radial outer end of the portion at the one side in the axial direction of the blade. An annular opening 30 is disposed on a radial inner surface of an impeller case 3 which encloses and houses the impeller. The shroud is disposed in the annular opening.SELECTED DRAWING: Figure 1A

Description

[Technical Field]

[0001] The present invention relates to a blower device and a vacuum cleaner. [Background technology]

[0002] Conventionally, impellers with three-dimensionally arranged blades have been used in air blowers for vacuum cleaners to improve rotational speed and fluid efficiency. Such impellers are sometimes called mixed-flow impellers. For example, the hub surface of an impeller extends like a disk with a curved surface resembling the outer surface of a cone with the rotation axis as its central axis. On the hub surface, multiple blades extend radially from the rotation axis and are arranged at equal intervals around the hub surface (see JP 2000-515944 A). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2000-515944 Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the blades of a mixed-flow impeller are not covered with a shroud, leakage flow of fluid occurring at the blade tips may deteriorate the fluid efficiency of the impeller.Furthermore, the leakage flow may affect the main flow of fluid, causing uneven relative velocity distribution between adjacent blades.

[0005] SUMMARY OF THE INVENTION The present invention aims to improve the performance of a blower having an impeller with a shroud disposed thereon. [Means for solving the problem]

[0006] An exemplary blower device of the present invention includes an impeller, a motor, and an impeller case. The impeller is rotatable about a rotation axis extending in the axial direction. The motor has a shaft. The shaft is rotatable together with the impeller. The impeller case is cylindrical and extends in the axial direction, and surrounds and houses the impeller. The impeller includes a hub, blades, and a shroud. The hub has a conical shape whose outer diameter, as viewed in the axial direction, decreases in one axial direction, and is connected to one axial end of the shaft. The blades are arranged in multiple circumferential directions, extending radially outward from a radially outer surface of the hub, and extend at least in the axial direction along the radially outer surface of the hub. The shroud is cylindrical and extends at least in the axial direction, surrounds one axial side portion of the blades and the rotation shaft, and is connected to the radially outer end of the one axial side portion of the blades. The impeller case has a radially inner surface on which an annular opening extending in a circumferential direction is disposed, and the shroud is disposed within the annular opening.

[0007] Moreover, the exemplary vacuum cleaner of the present invention includes the above-mentioned blower device.

[0008] Further features and advantages of the present invention will become more apparent from the following embodiments. [Effects of the Invention]

[0009] According to the exemplary blower device and vacuum cleaner of the present invention, the performance of a blower device having an impeller with a shroud disposed thereon can be improved. [Brief explanation of the drawings]

[0010] [Figure 1A] FIG. 1A is a cross-sectional view showing an example of the configuration of a blower device according to an embodiment. [Figure 1B] FIG. 1B is an enlarged cross-sectional view of a main part of the blower according to the embodiment. [Figure 2] FIG. 2 is an external view of the blower according to the embodiment. [Figure 3]FIG. 3 is an exploded perspective view of the blower according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram showing an example of a vacuum cleaner equipped with a blower device. [Figure 5] FIG. 5 is an external view showing a configuration example of an impeller according to an embodiment. [Figure 6A] FIG. 6A is an exploded perspective view of a blower according to a first modified example. [Figure 6B] FIG. 6B is an enlarged cross-sectional view showing an example of the configuration of the annular opening of the first modified example. [Figure 7A] FIG. 7A is an exploded perspective view showing a configuration example of a blower device according to a second modified example. [Figure 7B] FIG. 7B is an enlarged cross-sectional view showing an example of the configuration of the annular opening of the second modified example. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0012] In this specification, in the blower device 100, the direction parallel to the rotation axis J of the impeller 1, which will be described later, is referred to as the "axial direction Da." Within the axial direction Da, the direction from the motor 2 toward the impeller case 3, which will be described later, is referred to as the "one axial direction Da1," and the direction from the impeller case 3 toward the motor 2 is referred to as the "other axial direction Da2." Additionally, the direction perpendicular to the rotation axis J is referred to as the "radial direction," and the direction of rotation about the rotation axis J is referred to as the "circumferential direction." Within the radial direction, the direction approaching the rotation axis J is referred to as the "radial inward direction," and the direction away from the rotation axis J is referred to as the "radial outward direction."

[0013] In this specification, the term "annular" refers not only to a shape that is continuous and uninterrupted throughout the entire circumferential direction centered on the rotation axis J, but also to a shape that has one or more interruptions in a portion of the entire area centered on the rotation axis J. It also refers to a shape that describes a closed curve on a curved surface that intersects with the rotation axis J and is centered on the rotation axis J.

[0014] Furthermore, in the positional relationship between one of a direction, a line, and a plane and another, "parallel" includes not only a state in which they do not intersect at all no matter how far they are extended, but also a state in which they are substantially parallel. Furthermore, "perpendicular" and "orthogonal" each include not only a state in which they intersect at 90 degrees, but also a state in which they are substantially perpendicular and a state in which they are substantially orthogonal. In other words, "parallel," "perpendicular," and "orthogonal" each include a state in which there is an angular deviation in the positional relationship between the two to an extent that does not deviate from the spirit of the present invention.

[0015] It should be noted that these are names used merely for the purpose of explanation and are not intended to limit the actual positional relationships, directions, names, etc.

[0016] <1. Embodiment> FIG. 1A is a cross-sectional view showing an example of the configuration of a blower device 100 according to an embodiment. FIG. 1B is an enlarged cross-sectional view of a main part of the blower device 100 according to an embodiment. FIG. 2 is an external view of the blower device 100 according to an embodiment. FIG. 3 is an exploded perspective view of the blower device 100 according to an embodiment. FIG. 4 is a schematic view showing an example of a vacuum cleaner 500 incorporating the blower device 100. Note that FIG. 1A shows a cross-sectional structure obtained by virtually cutting the blower device 100 along a plane including the two-dot chain line IA-IA and the rotation axis J in FIG. 2. Also, FIG. 1B corresponds to a portion IB surrounded by a dashed line in FIG. 1A.

[0017] <1-1. Blower device 100> The blower device 100 is a fan device equipped with a so-called mixed-flow impeller, and sucks in an airflow (i.e., air) from a suction port 101 on one axial direction Da1. The airflow flows radially outward as it approaches the other axial direction Da2, and is then discharged from a discharge port 102 to the other axial direction Da2. However, without being limited to this example, the blower device 100 may also suck in and discharge fluids other than air, such as gases and liquids. For example, as shown in FIG. 4, the blower device 100 is mounted on a stick-type vacuum cleaner 500 that is integrally configured with a suction pipe 502 having a head 501 disposed at the tip and a main body 503. In other words, the vacuum cleaner 500 is equipped with the blower device 100. However, the use of the blower device 100 is not limited to this example. The blower device 100 may be installed in other types of vacuum cleaners, such as canister vacuum cleaners, hand cleaners, and robot vacuum cleaners, or in devices other than vacuum cleaners that are capable of suction and delivery of fluids such as airflow.

[0018] The blower device 100 includes an impeller 1, a motor 2, an impeller case 3, and a wind tunnel case 4.

[0019] The impeller 1 is rotatable around a rotation axis J (that is, in the circumferential direction) that extends in the axial direction Da. The impeller 1 is attached to a motor 2.

[0020] The motor 2 is a drive source that rotates the impeller 1, and is disposed on one axial direction Da1 side of the impeller 1. The motor 2 has a shaft 21 that extends in the axial direction Da along a rotation axis J that extends in the axial direction Da. The shaft 21 is rotatable together with the impeller 1 about the rotation axis J. More specifically, the impeller 1 is coupled to one axial end of the shaft 21. The motor 2 rotates the shaft 21 about the rotation axis J, thereby rotating the impeller 1 together with the shaft 21.

[0021] The impeller case 3 is cylindrical and extends in the axial direction Da, and surrounds and houses the impeller 1. Specifically, the impeller case 3 is a cylindrical member having a truncated cone shape whose outer and inner diameters decrease toward one side in the axial direction Da1, and is a single member in this embodiment. However, this example does not exclude a configuration in which the impeller case 3 is composed of multiple individual members.

[0022] One axial end of the impeller case 3 functions as a suction port 101. The other axial end of the impeller case 3 is joined to one axial end of the wind tunnel case 4 over its entire circumferential area. In other words, the two are joined without any gaps to prevent airflow leakage. The joining means is not particularly limited, but may be, for example, adhesive bonding, press-fitting, screwing, welding, brazing, etc.

[0023] Furthermore, an annular opening 30 extending in the circumferential direction is disposed on the radially inner surface of the impeller case 3. The annular opening 30 is recessed radially outward on the radially inner surface of the impeller case 3.

[0024] In this embodiment, the inner surface of the annular opening 30 has an annular first surface 301 and a cylindrical second surface 302 extending in the axial direction Da. The first surface 301 extends radially and faces, in the axial direction Da, one axial end of a shroud 13 (described later) of the impeller 1. The second surface 302 faces, in the radial direction, the other axial end of the shroud 13. The second surface 302 surrounds the other axial end of the shroud 13.

[0025] 1A and 1B, the second surface 302 preferably extends in the axial direction Da. However, the present invention is not limited to this example, and the second surface 302 may extend radially outward toward the other axial direction Da2. In other words, the second surface 302 may have a cylindrical shape or a truncated cone shape.

[0026] In this way, by attaching the impeller case 3 from one axial direction Da1 side of the impeller 1 toward the other axial direction Da2, the impeller 1 can be disposed within the impeller case 3, and in particular, the shroud 13 can be accommodated within the annular opening 30 of the impeller case 3. This makes it easy to attach the impeller case 3. Furthermore, when molding the impeller case 3 with a die, the impeller case 3 can be molded by removing the die in the axial direction Da. This makes it easy to mold the impeller case 3 without using a die with a complex shape. However, this example does not exclude a configuration in which the second surface 302 is neither cylindrical nor a truncated cone shape extending radially outward toward the other axial direction Da2.

[0027] The impeller case 3 has a case cylindrical portion 31, an inner edge portion 32, and an inner wall portion 33. The case cylindrical portion 31 is the main body of the impeller case 3 and is cylindrical and extends in the axial direction Da. The outer shape of the case cylindrical portion 31 is a truncated cone whose outer diameter decreases toward one axial direction Da1. The inner edge portion 32 is annular and surrounds the rotation axis J, and extends radially inward from the radially inner end portion of the case cylindrical portion 31. The inner wall portion 33 is cylindrical and extends in the axial direction Da, and extends from the radially inner end portion of the inner edge portion 32 toward the other axial direction Da2.

[0028] The portion of the case tubular portion 31 on one axial direction Da1 side, the inner edge portion 32, and the inner wall portion 33 form a cylindrical hollow portion 300 in the portion of the impeller case 3 on one axial direction Da1 side. The formation of the hollow portion 300 reduces the amount of material used for the impeller case 3. This allows the impeller case 3 to be made lighter and its manufacturing costs to be reduced.

[0029] A portion of the hollow portion 300 on the other axial direction Da2 side (for example, a portion closer to the other axial direction Da2 than the other axial end portion of the inner wall portion 33) functions as the annular opening 30. In this embodiment, a first surface 301 of the annular opening 30 facing the other axial direction Da2 is the other axial end face of the inner wall portion 33. In addition, the radially inner surface of the case cylindrical portion 31 includes a second surface 302 of the annular opening 30.

[0030] However, the example of this embodiment does not exclude a configuration in which the impeller case 3 does not have the inner edge portion 32 and the inner wall portion 33. For example, the impeller case 3 may be configured such that the annular opening 30 is formed on the radially inner surface of the case cylindrical portion 31. Also, the portion of the hollow portion 300 on the one axial direction Da1 side of the annular opening 30 does not need to be formed.

[0031] In this embodiment, the radially inner surface of the impeller case 3 and the radially inner surface of the shroud 13 have a truncated conical shape in which the inner diameter, as viewed in the axial direction Da, decreases toward one axial direction Da1. For example, a region of the radially inner surface of the cylindrical case portion 31 that is closer to the other axial direction Da2 than the annular opening 30, the radially inner surface of the shroud 13, and the radially inner surface of the inner wall portion 33 form an inner peripheral surface having the above-described truncated conical shape. Preferably, the inner peripheral surface is similar to the radially outer surface of the hub 11.

[0032] By making the radially inner surface of the impeller case 3 and the radially inner surface of the shroud 13 similar in shape to the radially outer surface of the hub 11, the airflow sucked in from one axial end of the impeller case 3 (i.e., the suction port 101) can be smoothly flowed radially outward from the hub 11.

[0033] Furthermore, since the gap between the blades 12 and the radially inner surface of the impeller case 3 can be reduced, leakage loss of the airflow at the blade tips of the blades 12 can be reduced. For example, if the flow path suddenly increases between the end of the radially inner surface of the shroud and the end of the radially inner surface of the impeller case, leakage loss at the blade tips may increase. Furthermore, the expansion of the flow path may increase secondary flow, which may result in further leakage loss. On the other hand, in this embodiment, the change in the flow path between the end of the radially inner surface of the shroud 13 and the end of the radially inner surface of the impeller case 3 is small. Therefore, the above-mentioned problem is unlikely to occur.

[0034] However, the above example does not exclude a configuration in which the radially inner surface of the impeller case 3 and the radially inner surface of the shroud 13 are not frustoconical in shape similar to (especially similar to) the radially outer surface of the hub 11 .

[0035] The air tunnel case 4 is cylindrical and surrounds at least a portion of the motor 2 on one axial direction Da1 side, and extends in the axial direction Da. The air tunnel case 4 faces the motor 2 radially with a gap therebetween, and forms an air tunnel 40 between the motor 2 and at least a portion of the motor 2 on one axial direction Da1 side. Within the air tunnel 40, air flows in the other axial direction Da2. As the impeller 1 rotates, the air flows from between the other axial end of the impeller case 3 and the one axial end of the motor 2 (or the impeller 1) into the one axial end Da1 of the air tunnel 40, and is then discharged from the other axial end of the air tunnel 40 to the outside of the blower device 100. The other axial end of the air tunnel 40 functions as a discharge outlet 102.

[0036] A plurality of stator vanes 41 are arranged in the circumferential direction inside the wind tunnel case 4. In other words, the blower 100 further includes a plurality of stator vanes 41. The stator vanes 41 extend in the axial direction Da and radial directions, and convert the speed of the air flowing in from the impeller 1 into pressure. The wind tunnel case 4 is supported by the motor 2 via the stator vanes 41. The radially outer end of each stator vane 41 is connected to the radially inner surface of the wind tunnel case 4. The radially inner end of each stator vane 41 is connected to the radially outer surface of the motor 2 (for example, the housing thereof).

[0037] <1-1-1. Impeller 1> Next, the configuration of the impeller 1 will be described with reference to Figures 1A to 3 and 5. Figure 5 is an external view showing an example of the configuration of the impeller 1 according to the embodiment.

[0038] The impeller 1 includes a hub 11, a plurality of blades 12, and a shroud 13. The hub 11, the plurality of blades 12, and the shroud 13 may each be made of resin or a metal such as aluminum (Al) or an alloy thereof. In this embodiment, the hub 11, the plurality of blades 12, and the shroud 13 are integral with each other, and preferably form a single member. However, this example does not exclude a configuration in which at least some of these components are separate from the other components.

[0039] The outer shape of the hub 11 is a cone extending in the axial direction Da. Here, the "cone shape" includes both a cone shape where the cone at the apex is not cut off and a truncated cone shape where the cone at the apex is cut off. The outer diameter of the hub 11 as viewed from the axial direction Da decreases toward one axial direction Da1. The hub 11 is connected to one axial end of the shaft 21.

[0040] In this embodiment, as shown in Figure 5 and other figures, the hub 11 is a covered cylinder having a truncated cone-shaped outer shape. In this specification, a shape in which one end of a cylinder (for example, the radial outer surface of the hub 11) is covered with a cover-shaped body (for example, one axial end surface of the hub 11) is referred to as a "covered cylinder." One axial end of the shaft 21 is housed inside the hub 11 and fixed to the hub 11. The center of rotation of the hub 11 is on the rotation axis J of the shaft 21.

[0041] The blades 12 extend radially outward from the radially outer surface of the hub 11 and are arranged in multiple numbers in the circumferential direction. That is, the multiple blades 12 are lined up in the circumferential direction on the radially outer surface of the hub 11. Each blade 12 extends at least in the axial direction Da along the radially outer surface of the hub 11, and, for example, moves in one circumferential direction as it extends in the other axial direction Da2 (see FIG. 5, etc.). However, this example does not exclude a configuration in which at least some of the blades 12 on the radially outer surface of the hub 11 extend in the axial direction Da. Each blade 12 is rotatable around the rotation axis J together with the shaft 21. The rotation of the blades 12 causes airflow to flow in the other axial direction Da2 and radially outward.

[0042] The shroud 13 has a cylindrical shape extending at least in the axial direction Da, and surrounds the portion of the blade 12 on one axial direction Da1 side and the rotation axis J. The shroud 13 is arranged on the portion of the blade 12 on one axial direction Da1 side, and is connected to the blade tip (i.e., the radially outer end). In other words, the shroud 13 is arranged on the radially inner side of the blade 12, and is connected to the blade tip. The shroud 13 is not arranged on or connected to the blade tip (i.e., the radially outer end) of the portion of the blade 12 on the other axial direction Da2 side (in other words, the radially outer side portion).

[0043] By arranging the shroud 13 on the axial side Da1 of the blade 12 (in other words, the radially inner side), the performance of the blower device 100 having the impeller 1 on which the shroud 13 is arranged can be improved.

[0044] For example, the centrifugal force acting on the shroud 13 due to the rotation of the impeller 1 reduces the stress generated between the blades 12 and the shroud 13. As a result, deformation of the impeller 1 due to the stress is reduced, and the shroud 13 is less likely to come off the blades 12.

[0045] Furthermore, it is possible to suppress airflow leakage that occurs in the gap between the blades 12 and the impeller case 3, and also to suppress uneven distribution of the relative speed of the airflow between circumferentially adjacent blades 12. Furthermore, compared to a configuration in which the shroud 13 is disposed over the entire blades 12 in the axial direction Da, it is possible to improve the total pressure efficiency of the impeller 1 alone. Note that the total pressure efficiency is the pressure increase efficiency of the impeller 1 alone, calculated from the total pressure difference between the upstream side (intake side) and downstream side (exhaust side) of the impeller 1. Due to these effects, the blower device 100 can improve the fluid efficiency of the impeller 1.

[0046] Furthermore, by connecting a portion of the blades 12 (i.e., a portion on one axial side Da1) to the cylindrical shroud 13, stress applied to the boundary portion (or connecting portion) between the blades 12 and the shroud 13 can be reduced compared to a configuration in which the entire blades 12 are connected to the shroud 13. Therefore, the shroud 13 is less likely to come off the blades 12, and the life of the impeller 1 can be extended.

[0047] Furthermore, in addition to the uniform distribution of the relative speed of the airflow between adjacent blades 12, the flow velocity distribution of the airflow discharged from between the impeller 1 and the impeller case 3 is also uniform. Therefore, the blower device 100 can reduce noise generated downstream of the area between the impeller 1 and the impeller case 3. For example, noise (such as discrete frequency noise) caused by interference with the stator vanes 41 arranged in the wind tunnel 40 can be reduced.

[0048] 1A and 1B, the shroud 13 is disposed within the annular opening 30 of the impeller case 3. In this way, even if a component of the centrifugal force generated by the rotation of the impeller 1, directed in one axial direction Da1, acts on the shroud 13, the first surface 301 of the annular opening 30 facing the one axial end of the shroud 13 in the axial direction Da can prevent the shroud 13 (and the impeller 1 itself) from lifting up in the one axial direction Da1. This also prevents the shroud 13 from becoming detached from the blades 12 due to the above-mentioned component force. Therefore, it is possible to suppress or prevent the shroud 13 from lifting up and becoming detached from the blades 12 in the impeller 1 of the blower 100.

[0049] Preferably, the shroud 13 is disposed within the annular opening 30 and closely faces the inner surface of the annular opening 30. In other words, the distances W1 and W2 between the axial ends of the shroud 13 and the inner surface of the annular opening 30 are smaller than the thickness ds of the shroud 13 (see FIG. 1B). Here, the thickness ds of the shroud 13 is the distance between the radially outer surface and the radially inner surface of the shroud 13, or in other words, the shortest distance from one of them to the other.

[0050] For example, in the present embodiment, a distance W1 in the axial direction Da between one axial end of the shroud 13 and an inner surface facing the other axial direction Da2 of the annular opening 30 (for example, the other axial end surface of the inner wall portion 33 in FIGS. 1A and 1B) is smaller than a thickness ds of the shroud 13. Furthermore, a distance W2 in the radial direction between (the radially outer end of) the other axial end of the shroud 13 and an inner surface of the annular opening 30 (for example, the second surface 302 in FIGS. 1A and 1B) is smaller than a thickness ds of the shroud 13.

[0051] This narrows the gap between the shroud 13 and the inner surface of the annular opening 30. Therefore, even if there is a pressure difference between the upstream side (intake side) and downstream side (delivery side) of the gap, a portion of the airflow flowing downstream is less likely to return to the upstream side through the gap. This prevents a decrease in the fluid efficiency of the impeller 1. However, this example does not exclude a configuration where W1 ≥ ds, or a configuration where W2 ≥ ds.

[0052] Preferably, the extension length Ls of the shroud 13 extending at least in the axial direction Da is 15% to 25% of the extension length Lb of the blade 12 extending at least in the axial direction Da along the radially outer surface of the hub 11. For example, the extension length Ls is the shortest distance from one axial end to the other axial end of the shroud 13 along the radially inner surface of the shroud 13 (see FIG. 1B). Also, the extension length Lb is the distance from one axial end to the other axial end of the blade 12 along the radially outer end of the blade 12 (see FIG. 1A).

[0053] By satisfying the relationship 0.15≦(Ls / Lb)≦0.25, the blower device 100 can achieve a good balance between reducing the stress applied to the boundary portion between the blades 12 and the shroud 13 and improving the fluid efficiency of the impeller 1. Therefore, the blower device 100 can improve the fluid efficiency of the impeller 1 while suppressing or preventing the shroud 13 from lifting up and coming off the blades 12.

[0054] If the extension length Ls of the shroud 13 is less than 15% of the extension length Lb of the blades 12, the effects of making the distribution of the relative velocity of the airflow between the circumferentially adjacent blades 12 uniform and improving the total pressure efficiency of the impeller 1 alone will be reduced. Therefore, there is a risk that the fluid efficiency of the impeller 1 will not be sufficiently improved. Furthermore, there is a risk that the effect of suppressing noise such as broadband noise and discrete frequency noise will be reduced or not realized.

[0055] Furthermore, if the extension length Ls of the shroud 13 is greater than 25% of the extension length Lb of the blades 12, a large stress is applied to the boundary between the blades 12 and the shroud 13. As a result, there is a risk that the shroud 13 may easily come off the blades 12.

[0056] However, the above examples do not exclude a configuration where (Ls / Lb)<0.15, nor do they exclude a configuration where 0.25<(Ls / Lb).

[0057] Preferably, one axial end of the shroud 13 is located on one axial side Da1 of the blade 12 (one axial end of the blade 12). More preferably, the axial width Wa between the one axial end of the shroud 13 and the one axial end of the blade 12 is 10% to 30% of the axial width Ws of the shroud 13 (see FIG. 1B). For example, the axial width Wa is the distance between the one axial end of the shroud 13 and the one axial end of the blade 12 in the axial direction Da, in other words, the shortest distance between them as viewed in the radial direction. The axial width Ws is the distance between the one axial end and the other axial end of the shroud 13 in the axial direction Da, in other words, the shortest distance between them as viewed in the radial direction.

[0058] By setting the relationship 0.10≦(Wa / Ws)≦0.30, leakage of airflow occurring in the gap between the blades 12 and the impeller case 3 can be more effectively suppressed. This makes it possible to make the distribution of the relative speed of the airflow between the blades 12 adjacent in the circumferential direction more uniform. Therefore, the blower device 100 can more effectively improve the fluid efficiency of the impeller 1.

[0059] Furthermore, if the above-mentioned axial width Wa is less than 10% of the axial width Ws of the shroud 13, the effects of suppressing airflow leakage and uniformizing the distribution of the relative velocity of the airflow between the blades 12 as described above will be reduced, and there is a risk that the fluid efficiency of the impeller 1 will not be sufficiently improved.

[0060] Furthermore, if the axial width Wa is greater than 30% of the axial width Ws of the shroud 13, the shroud 13 will be positioned closer to the hub 11 in the axial direction Da1, which may increase the axial size of the impeller 1 and result in an increase in the size of the blower 100. Alternatively, if the axial width Wa of the blades 12 (see FIG. 1B ) is shortened to make the axial width Wa greater than 30% of the axial width Ws of the shroud 13, it will be difficult for the blades 12 to deliver the airflow. The axial width Wb is the distance between the one axial end and the other axial end of the blade 12 in the axial direction Da; in other words, it is the shortest distance between them as viewed from the radial direction. This may result in a decrease in the fluid efficiency of the impeller 1.

[0061] However, the above example does not exclude a configuration in which one axial end of the shroud 13 is located at a position Da2 on the other axial side relative to one axial end of the blade 12. Furthermore, the above example does not exclude a configuration in which (Wa / Ws)<0.10, nor does it exclude a configuration in which 0.30<(Wa / Ws).

[0062] <1-2. First Modification of the Embodiment> Next, a first modified example of the embodiment will be described with reference to Figures 6A and 6B. Figure 6 is an exploded perspective view of a blower device 100 according to the first modified example. Figure 6B is an enlarged cross-sectional view showing an example of the configuration of the annular opening 30 of the first modified example. Note that Figure 6B corresponds to the portion IB surrounded by the dashed line in Figure 1A. Below, configurations that differ from the above-described embodiment will be described. However, the same components as those in the above-described embodiment will be assigned the same reference numerals, and descriptions of configurations similar to those in the above-described embodiment may be omitted.

[0063] In the first modified example, as shown in FIGS. 6A and 6B , the impeller case 3 further includes an annular protrusion 34. The annular protrusion 34 has an annular shape surrounding the rotation axis J, protrudes radially inward from the radially inner surface of the cylindrical case portion 31, and extends circumferentially. The annular protrusion 34 is positioned on the other axial side Da2 of the inner wall portion 33 relative to the other axial end of the inner wall portion 33, and forms an annular opening 30 between the other axial end of the inner wall portion 33 and the other axial end of the inner wall portion 33. The one axial end face (the radially outer end) of the annular protrusion 34 faces the other axial end of the shroud 13 in the axial direction Da. Preferably, the two are closely opposed to each other, and a distance W3 between them in the axial direction Da is smaller than a thickness ds of the shroud 13 (see FIG. 6B ). However, this example does not exclude a configuration in which the above-mentioned distance W3 is equal to or greater than the thickness ds of the shroud 13.

[0064] Furthermore, the impeller case 3 is made up of multiple members divided by an imaginary plane including the rotation axis J. For example, as shown in Fig. 6A, the impeller case 3 is made up of case pieces 35 obtained by dividing the impeller case 3 into two. However, without being limited to the example shown in Fig. 6A, the impeller case 3 may be divided into three or more pieces. In other words, the impeller case 3 may be made up of three or more case pieces 35.

[0065] When the impeller case 3 is attached to the impeller 1, each case piece 35 is attached to the impeller 1 from the radially outer side toward the radially inner side so as to sandwich the impeller 1 in the radial direction. At this time, the shroud 13 is inserted radially into the divided annular openings 30 of each case piece 35. Then, the circumferentially opposing ends of each case piece 35 are joined together. The joining means used at this time is not particularly limited, and may be, for example, adhesive bonding, press-fitting, screwing, welding, brazing, or the like.

[0066] As described above, by attaching the above-mentioned multiple members (i.e., case pieces 35) from the radially outer side toward the radially inner side of the impeller 1, the impeller 1 can be disposed within the impeller case 3, and in particular, the shroud 13 can be housed within the annular opening 30 of the impeller case 3. This configuration is effective, for example, when the inner surface of the annular opening 30 has a surface that faces the other axial end of the shroud 13 in the axial direction Da (for example, one axial end surface of the annular protrusion 34).

[0067] The shaft 21 may be connected to the impeller 1 before or after the impeller case 3 is attached to the impeller 1. After the impeller case 3 is attached to the impeller 1, the impeller case 3 is attached to and joined to the wind tunnel case 4.

[0068] <1-3. Second Modification of the Embodiment> Next, a second modified example of the embodiment will be described with reference to Figures 7A and 7B. Figure 7A is an exploded perspective view showing an example of the configuration of a blower device 100 according to the second modified example. Figure 7B is an enlarged cross-sectional view showing an example of the configuration of an annular opening 30 of the second modified example. Note that Figure 7B corresponds to the portion IB surrounded by the dashed line in Figure 1A. Below, configurations that differ from the above-described embodiment and its first modified example will be described. However, the same reference numerals will be used to designate components that are the same as those in the above-described embodiment and its first modified example, and descriptions of configurations that are the same as those in the above-described embodiment and its first modified example may be omitted.

[0069] In the second modified example, the impeller case 3 is composed of multiple individual components. For example, as shown in FIGS. 7A and 7B , the impeller case 3 has a first case 36 and a second case 37. The first case 36 is cylindrical and surrounds at least one axial end of the shroud 13. The second case 37 is connected to the other axial end of the first case 36 and surrounds the portion of the impeller 1 on the other axial direction Da2 side. For example, as shown in FIGS. 7A and 7B , the impeller case 3 is divided into two by an imaginary plane that is perpendicular to the rotation axis J and includes one axial end face of the annular protrusion 34. The portion of the impeller case 3 on the one axial direction Da1 side of the plane is the first case 36, and the portion on the other axial direction Da2 side of the plane is the first case 36.

[0070] Furthermore, in the second modified example, the second case 37 is made up of multiple members divided by an imaginary plane including the rotation axis J. For example, as shown in FIG. 7A, the second case 37 is made up of second case halves 370 obtained by dividing the second case 37 into two. However, without being limited to the example shown in FIG. 7A, the second case 37 may be divided into three or more multiple parts. In other words, the second case 37 may be made up of three or more multiple second case halves 370.

[0071] When attaching the impeller case 3 to the impeller 1, each second case half 370 is attached to a portion of the impeller 1 located on the other axial direction Da2 side of the annular protrusion 34 from the radially outer side toward the radially inner side so as to sandwich the portion in the radial direction. At this time, the other axial end of the shroud 13 faces one axial end of the annular protrusion 34. Then, the circumferential ends of the second case half 370 that face each other in the circumferential direction are joined together. The joining means used at this time is not particularly limited, and may be, for example, adhesive bonding, welding, brazing, or the like.

[0072] Furthermore, when the first case 36 is attached to the second case 37, the first case 36 is attached to the one axial end face of the second case 37 so as to cover the portion of the impeller 1 on the one axial direction Da1 side (particularly the shroud 13) from the one axial direction Da1 side toward the other axial direction Da2. At this time, the shroud 13 is disposed between the other axial end of the inner wall portion 33 of the first case 36 and the one axial end face of the annular protrusion 34 of the second case half 370. As a result, the shroud 13 is disposed within the annular opening 30 formed between the other axial end of the inner wall portion 33 and the one axial end face of the annular protrusion 34. The other axial end of the first case 36 and the one axial end of the second case 37 are joined. The joining means used at this time is not particularly limited, and may be, for example, adhesive bonding, press-fitting, screwing, welding, brazing, or the like.

[0073] As described above, the second case 37 can be assembled by attaching the above-mentioned multiple members (i.e., the second case piece 370) to the portion of the impeller 1 on the other axial direction Da2 side from the radially outer side toward the radially inner side. Thereafter, the first case 36 is attached to the shroud 13 from the one axial direction Da1 side toward the other axial direction Da2, and joined to one axial end of the second case 37, thereby assembling the impeller case 3. In particular, the shroud 13 can be housed within the annular opening 30 of the impeller case 3. This configuration is effective, for example, when the inner surface of the annular opening 30 has a surface that faces the other axial end of the shroud 13 in the axial direction Da.

[0074] <2. Notes> The above describes an embodiment of the present invention. Note that the above embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each process, and that these modifications are within the scope of the present invention.

[0075] <3. Summary> The following will provide an overview of the embodiments described so far.

[0076] For example, the blower device disclosed herein may an impeller rotatable about a rotation axis extending in the axial direction; a motor having a shaft rotatable with the impeller; an impeller case that is cylindrical and extends in the axial direction and surrounds and houses the impeller; Equipped with The impeller is a hub having a conical shape whose outer diameter, as viewed in the axial direction, decreases toward one end in the axial direction and which is connected to one end of the shaft in the axial direction; a plurality of blades arranged in a circumferential direction and extending radially outward from the radially outer surface of the hub, the blades extending at least in the axial direction along the radially outer surface of the hub; a shroud having a cylindrical shape extending at least in the axial direction, surrounding one axial side portion of the blade and the rotary shaft, and connected to a radially outer end portion of the one axial side portion of the blade; and A circular opening extending in a circumferential direction is disposed on a radially inner surface of the impeller case, The shroud is configured to be disposed within the annular opening (first configuration).

[0077] The blower device of the first configuration is The extension length of the shroud extending at least in the axial direction may be 15% or more and 25% or less of the extension length of the blade extending at least in the axial direction along the radially outer surface of the hub (second configuration).

[0078] Furthermore, the blower device of the first or second configuration is one axial end of the shroud is located one axially further to the blade, The axial width between one axial end of the shroud and one axial end of the blade may be 10% to 30% of the axial width of the shroud (third configuration).

[0079] In addition, the blower device having any one of the first to third configurations described above may A configuration (fourth configuration) may be employed in which the distance between the axial end of the shroud and the inner surface of the annular opening is smaller than the thickness of the shroud.

[0080] In addition, the blower device having any one of the first to fourth configurations described above may The inner surface of the annular opening is a first surface having an annular shape that extends radially and faces one axial end of the shroud in the axial direction; a cylindrical second surface that faces the other axial end of the shroud in a radial direction; and The second surface may be configured to extend in the axial direction, or to extend radially outward as it moves toward the other axial direction (fifth configuration).

[0081] In addition, the blower device having any one of the first to fifth configurations described above may The impeller case may be configured (sixth configuration) to be composed of a plurality of members divided by an imaginary plane including the rotation axis.

[0082] In addition, the blower device having any one of the first to fifth configurations described above may The impeller case is a cylindrical first case surrounding at least one axial end of the shroud; a second case connected to the other axial end of the first case and surrounding the other axial side portion of the impeller; and The second case may be configured (seventh configuration) to be composed of a plurality of members divided by an imaginary plane including the rotation axis.

[0083] In addition, the blower device having any one of the first to seventh configurations described above may The radially inner surface of the impeller case and the radially inner surface of the shroud may have a truncated cone shape whose inner diameter, as viewed in the axial direction, decreases in one axial direction (eighth configuration).

[0084] The vacuum cleaner disclosed in this specification has a configuration (ninth configuration) including the air blower device having any one of the first to eighth configurations. [Industrial Applicability]

[0085] The present invention is useful in devices for aspirating and dispensing fluids. [Explanation of symbols]

[0086] 100 blower, 101 suction port, 102 outlet port, 1 impeller, 11 hub, 12 rotor blade, 13 shroud, 2 motor, 21 shaft, 3 impeller case, 30 annular opening, 300 cavity, 301 first surface, 302 second surface, 31 case cylindrical portion, 32 inner edge portion, 33 inner wall part, 34 annular convex part, 35 case piece, 36 first case, 37 second case, 370 second case piece, 4 wind tunnel case, 40 wind tunnel, 41 stator blade, 500 vacuum cleaner, 501 head, 502 suction pipe, 503 main body part, J rotating shaft, Da axial direction, Da1 one axial direction, Da2 other axial direction

Claims

1. an impeller rotatable about a rotation axis extending in the axial direction; a motor having a shaft rotatable with the impeller; an impeller case that is cylindrical and extends in the axial direction and surrounds and houses the impeller; Equipped with The impeller is a hub having a conical shape whose outer diameter, as viewed in the axial direction, decreases toward one end in the axial direction and which is connected to one end of the shaft in the axial direction; a plurality of blades arranged in a circumferential direction and extending radially outward from the radially outer surface of the hub, the blades extending at least in the axial direction along the radially outer surface of the hub; a shroud having a cylindrical shape extending at least in the axial direction, surrounding one axial side portion of the blade and the rotary shaft, and connected to a radially outer end portion of the one axial side portion of the blade; and A circular opening extending in a circumferential direction is disposed on a radially inner surface of the impeller case, The shroud is disposed within the annular opening.

2. 2. The blower device of claim 1, wherein an extension length of the shroud extending at least in the axial direction is 15% or more and 25% or less of an extension length of the blade extending at least in the axial direction along the radially outer surface of the hub.

3. one axial end of the shroud is located one axially further to the blade, 2. The blower device according to claim 1, wherein an axial width between one axial end of the shroud and one axial end of the blade is equal to or greater than 10% and equal to or less than 30% of the axial width of the shroud.

4. The blower device according to claim 1 , wherein a distance between an axial end of the shroud and an inner surface of the annular opening is smaller than a thickness of the shroud.

5. The inner surface of the annular opening is a first surface having an annular shape that extends radially and faces one axial end of the shroud in the axial direction; a cylindrical second surface that faces the other axial end of the shroud in a radial direction; and The blower device according to claim 1 , wherein the second surface extends in the axial direction or extends radially outward as it moves toward the other axial direction.

6. The blower device according to claim 1 , wherein the impeller case is made up of a plurality of members divided by an imaginary plane including the rotation axis.

7. The impeller case is a cylindrical first case surrounding at least one axial end of the shroud; a second case connected to the other axial end of the first case and surrounding the other axial side portion of the impeller; and The blower device according to claim 1 , wherein the second case is made up of a plurality of members divided by an imaginary plane including the rotation axis.

8. 2. The blower device according to claim 1, wherein the radially inner surface of the impeller case and the radially inner surface of the shroud have a truncated conical shape whose inner diameter, as viewed in the axial direction, decreases in one axial direction.

9. A vacuum cleaner comprising the air blower device according to any one of claims 1 to 8.

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