Air supply device and dust collector

Abstract

The utility model provides an air supply device and a dust collector. The impeller of the blower device can rotate together with the shaft of the motor around a rotating shaft extending in the axial direction. The hub of the impeller has a conical shape in which the outer diameter becomes smaller toward one axial direction. The plurality of blades extend from the radial outer side surface of the hub to the radial outer side, are arranged in the circumferential direction, and extend at least in the axial direction along the radial outer side surface of the hub. A cylindrical shroud surrounds the rotating shaft and a portion of the blade on one side in the axial direction, and is connected to a radially outer end portion of the portion of the blade on one side in the axial direction. An annular opening part is arranged on the radial inner side surface of an impeller shell which surrounds and accommodates the impeller. And the shield is arranged in the circular ring opening part.

Description

Technical Field

[0001] This utility model relates to an air supply device and a vacuum cleaner. Background Technology

[0002] In the past, in the air supply devices used in vacuum cleaners, impellers with blades formed in three dimensions were used to improve rotational speed and fluid efficiency. Such impellers are sometimes called oblique flow impellers. For example, the hub surface of the impeller has a curved surface like the outer surface of a cone with the rotation axis as the center, extending like a disk. On this hub surface, multiple blades extend radially along the hub surface with the rotation axis as the center, and are arranged at equal intervals in the circumferential direction of the hub surface (see Japanese Patent Publication No. 2000-515944).

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent Publication No. 2000-515944

[0005] However, in a mixed-flow impeller, when the blades are not covered by a shroud, the impeller's fluid efficiency may deteriorate due to fluid leakage at the blade tips. Furthermore, because this leakage affects the mainstream fluid flow, the relative velocity distribution between adjacent blades may become uneven. Utility Model Content

[0006] The purpose of this invention is to improve the performance of an air supply device with an impeller equipped with a protective cover.

[0007] An exemplary air supply device of this utility model includes an impeller, a motor, and an impeller housing. The impeller is rotatable about a rotating shaft extending axially. The motor has a shaft. The shaft is rotatable together with the impeller. The impeller housing is a cylindrical shape extending axially and surrounds and houses the impeller. The impeller has a hub, blades, and a shroud. The hub is a conical shape with an outer diameter decreasing as it faces axially, and is connected to one axial end of the shaft. Multiple blades are arranged circumferentially extending radially outward from the radially outer side of the hub, and extend at least axially along the radially outer side of the hub. The shroud is a cylindrical shape extending at least axially and surrounds a portion of the blades on one axial side and the rotating shaft, and is connected to the radially outer end of the portion of the blades on one axial side. A circumferentially extending annular opening is disposed on the radially inner side of the impeller housing. The shroud is disposed within the annular opening.

[0008] The extension length of the shroud extending at least axially is more than 15% and less than 25% of the extension length of the blade extending at least axially along the radial outer side of the hub.

[0009] One axial end of the shield is located further axially than the blade, and the axial width between the axial end of the shield and the axial end of the blade is more than 10% and less than 30% of the axial width of the shield.

[0010] The distance between the axial end of the shield and the inner surface of the annular opening is smaller than the thickness of the shield.

[0011] The inner surface of the annular opening has: a first annular face that extends radially and is axially opposite to one end of the shield; and a second cylindrical face that is radially opposite to the other end of the shield, the second face extending axially or radially outward as it moves toward the other axial direction.

[0012] The impeller housing is composed of multiple parts divided by an imaginary plane containing the rotating shaft.

[0013] The impeller housing has: a cylindrical first housing surrounding at least one axial end of the shroud; and a second housing connected to the other axial end of the first housing and surrounding a portion of the impeller on the other axial side, the second housing being composed of a plurality of components divided by an imaginary plane containing the rotating shaft.

[0014] The radially inner surface of the impeller housing and the radially inner surface of the shroud are frustoconical shapes, with the inner diameter decreasing as viewed from the axial direction.

[0015] In addition, the exemplary vacuum cleaner of this utility model includes the above-mentioned air supply device.

[0016] Further features and advantages of this utility model are further illustrated by the embodiments shown below.

[0017] The effects of this utility model are as follows.

[0018] According to the exemplary air supply device and vacuum cleaner of this utility model, the performance of an air supply device having an impeller equipped with a protective cover can be improved. Attached Figure Description

[0019] Figure 1A This is a cross-sectional view showing a structural example of the air supply device according to an embodiment.

[0020] Figure 1B This is an enlarged cross-sectional view of the main part of the air supply device in the embodiment.

[0021] Figure 2 This is an external view of the air supply device according to the implementation method.

[0022] Figure 3This is an exploded perspective view of the air supply device in the embodiment.

[0023] Figure 4 This is a schematic diagram showing an example of a vacuum cleaner equipped with a blower.

[0024] Figure 5 This is an external view showing an example of the structure of the impeller in the embodiment.

[0025] Figure 6A This is an exploded perspective view of the air supply device in the first modified example.

[0026] Figure 6B This is a cross-sectional view showing an enlarged view of the structure of the annular opening in the first modified example.

[0027] Figure 7A This is an exploded perspective view showing the structure of the air supply device of the second modified example.

[0028] Figure 7B This is a cross-sectional view showing an enlarged view of the structure of the annular opening in the second modified example.

[0029] In the diagram: 100—Air supply device, 101—Suction port, 102—Outlet, 1—Impeller, 11—Hub, 12—Blade, 13—Guard, 2—Motor, 21—Shaft, 3—Impeller housing, 30—Annular opening, 300—Cavity, 301—First surface, 302—Second surface, 31—Housing cylinder, 32—Inner edge, 33—Inner wall, 34—Annular protrusion, 35—Housing plate, 36—First housing, 37—Second housing, 370—Second housing plate, 4—Wind tunnel housing, 40—Wind tunnel, 41—Stationary blade, 500—Vacuum cleaner, 501—Head, 502—Suction pipe, 503—Main body, J—Rotating shaft, Da—Axial direction, Da1—One side of the axial direction, Da2—The other side of the axial direction. Detailed Implementation

[0030] The embodiments of this utility model will now be described with reference to the accompanying drawings.

[0031] It should be noted that, in this specification, in the air supply device 100, the direction parallel to the rotation axis J of the impeller 1 (described later) is referred to as "axial direction Da". The direction from the motor 2 towards the impeller housing 3 within axial direction Da is referred to as "axial direction one Da1", and the direction from the impeller housing 3 towards the motor 2 is referred to as "axial direction other Da2". Furthermore, the direction orthogonal to the rotation axis J is referred to as "radial", and the direction of rotation centered on the rotation axis J is referred to as "circumferential direction". The direction closer to the rotation axis J within the radial direction is referred to as "radial inner side", and the direction farther from the rotation axis J is referred to as "radial outer side".

[0032] Furthermore, in this specification, "ring-shaped" includes not only a shape that is continuously connected without seams over the entire circumferential region centered on the rotation axis J, but also a shape having one or more seams over a portion of the entire region centered on the rotation axis J. Additionally, it also includes a shape on a curved surface that depicts a closed curve centered on and intersecting the rotation axis J.

[0033] Furthermore, in the positional relationship between any two elements—orientation, line, and plane—and any other element, "parallel" includes not only a state where they never intersect regardless of where they extend, but also a state of being substantially parallel. Similarly, "perpendicular" and "orthogonal" include not only a state where they intersect at 90 degrees, but also a state of being substantially perpendicular and substantially orthogonal. In other words, "parallel," "perpendicular," and "orthogonal" respectively include states where there is an angular offset in their positional relationship that does not depart from the spirit of this invention.

[0034] It should be noted that these names are used for illustrative purposes only and are not intended to define actual positional relationships, directions, or names.

[0035] <1. Implementation Method>

[0036] Figure 1A This is a cross-sectional view showing a structural example of the air supply device 100 according to an embodiment. Figure 1B This is an enlarged cross-sectional view of the main part of the air supply device 100 in the embodiment. Figure 2 This is an external view of the air supply device 100 according to the embodiment. Figure 3 This is an exploded perspective view of the air supply device 100 according to the embodiment. Figure 4 This is a schematic diagram showing an example of a vacuum cleaner 500 equipped with a blower 100. It should be noted that... Figure 1A It shows the use of containing Figure 2 The double-dotted line IA-IA and the plane of the rotating axis J imaginarily cut off the cross-sectional structure of the air supply device 100. Furthermore, Figure 1B Corresponding to Figure 1A The part IB enclosed by the dashed line.

[0037] <1-1. Air supply device 100>

[0038] The air supply device 100 is a fan device equipped with a so-called diagonal-flow impeller, which draws airflow (i.e., air) from the suction port 101 on one axial side, Da1. This airflow flows radially outward toward the other axial side, Da2, and is discharged from the discharge port 102 toward the other axial side, Da2. However, it is not limited to this example; the air supply device 100 can also draw in and discharge fluids other than air, such as gases and liquids. For example, Figure 4As shown, the air supply device 100 is mounted on a stick-shaped vacuum cleaner 500, which is integrally formed by a suction tube 502 with a head 501 disposed at the front end and a main body 503. That is, the vacuum cleaner 500 has an air supply device 100. However, the application of the air supply device 100 is not limited to this example. The air supply device 100 can be mounted on other types of vacuum cleaners such as canister vacuum cleaners, handheld cleaners, and robotic vacuum cleaners, and can also be mounted on devices other than vacuum cleaners capable of suction and delivery of fluids such as airflow.

[0039] The air supply device 100 includes an impeller 1, a motor 2, an impeller housing 3, and a wind tunnel housing 4.

[0040] Impeller 1 is capable of rotating about a rotating shaft J extending along the axial direction Da (i.e., circumferentially). Impeller 1 is mounted on motor 2.

[0041] Motor 2 is the drive source for rotating impeller 1, and is disposed on the axial side Da1 of impeller 1. Motor 2 has a shaft 21 extending along the axial direction Da, which is a rotating shaft J. Shaft 21 is capable of rotating together with impeller 1 about the rotating shaft J. Specifically, impeller 1 is connected to one axial end of shaft 21. Motor 2 rotates shaft 21 about the rotating shaft J, thereby causing impeller 1 to rotate together with shaft 21.

[0042] The impeller housing 3 is a cylindrical shape extending along the axial direction Da, and surrounds and houses the impeller 1. Specifically, the impeller housing 3 is a frustum-shaped cylindrical component whose outer and inner diameters decrease as it faces the axial direction Da1; in this embodiment, it is a single component. However, this example does not preclude a structure in which the impeller housing 3 is composed of multiple independent components.

[0043] One axial end of the impeller housing 3 functions as an intake port 101. The other axial end of the impeller housing 3 is engaged with one axial end of the wind tunnel housing 4 over its entire circumferential area. That is, the two are engaged without gaps to prevent airflow leakage. The engagement method is not particularly limited, and can be, for example, bonding, press-fitting, threaded connection, fusion, brazing, etc.

[0044] Furthermore, an annular opening 30 extending circumferentially is provided on the radially inner surface of the impeller housing 3. The annular opening 30 is recessed radially outward on the radially inner surface of the impeller housing 3.

[0045] In this embodiment, the inner surface of the annular opening 30 has a first annular surface 301 and a second cylindrical surface 302 extending along the axial direction Da. The first surface 301 extends radially and is opposed to one axial end of the shroud 13 of the impeller 1 (described later) along the axial direction Da. The second surface 302 is opposed to the other axial end of the shroud 13 radially. The second surface 302 surrounds the other axial end of the shroud 13.

[0046] In this embodiment, such as Figure 1A and Figure 1B As shown, the second surface 302 preferably extends along the axial direction Da. However, it is not limited to this example; the second surface 302 may also extend radially outward toward the opposite axial direction Da2. That is, the second surface 302 may be cylindrical or frustum conical.

[0047] Thus, by mounting the impeller housing 3 from one axial direction Da1 towards the other axial direction Da2 of the impeller 1, the impeller 1 can be positioned within the impeller housing 3, and in particular, the shroud 13 can be housed within the annular opening 30 of the impeller housing 3. Therefore, the installation of the impeller housing 3 can be easily performed. Furthermore, when molding the impeller housing 3, the impeller housing 3 can be formed by pulling out the mold along the axial direction Da. Therefore, the impeller housing 3 can be easily formed without using a mold with a complex shape. However, this example does not preclude a structure where the second surface 302 is neither cylindrical nor a frustum-shaped cone extending radially outward towards the other axial direction Da2.

[0048] The impeller housing 3 has a housing cylindrical portion 31, an inner edge portion 32, and an inner wall portion 33. The housing cylindrical portion 31 is the main body of the impeller housing 3 and is cylindrical in shape extending along the axial direction Da. The outer diameter of the housing cylindrical portion 31 is a frustum-shaped cone that decreases as it faces the axial direction Da1. The inner edge portion 32 is an annular shape surrounding the rotating shaft J and extends radially inward from the radially inner end of the housing cylindrical portion 31. The inner wall portion 33 is cylindrical in shape extending along the axial direction Da and extends radially inward from the radially inner end of the inner edge portion 32 in the opposite axial direction Da2.

[0049] The portion of the casing cylinder 31 on one axial side (Da1), the inner edge portion 32, and the inner wall portion 33 on the axial side (Da1) of the impeller casing 3 form a cylindrical cavity 300. By forming the cavity 300, the material of the impeller casing 3 can be reduced. Therefore, the impeller casing 3 can be made lighter and its manufacturing cost can be reduced.

[0050] The portion of the cavity 300 on the axially opposite side Da2 (e.g., the portion further on the axially opposite side Da2 than the axially opposite end of the inner wall portion 33) functions as an annular opening 30. In this embodiment, the first surface 301 of the annular opening 30 facing the axially opposite side Da2 is the axially opposite end face of the inner wall portion 33. Furthermore, the radially inner surface of the housing cylinder portion 31 includes the second surface 302 of the annular opening 30.

[0051] However, this embodiment does not preclude the impeller housing 3 from having an inner edge portion 32 and an inner wall portion 33. For example, the impeller housing 3 may also have a structure in which an annular opening portion 30 is formed on the radially inner side of the housing cylinder portion 31. Alternatively, the portion of the cavity portion 300 that is further axially towards the Da1 side than the annular opening portion 30 may not be formed.

[0052] Furthermore, in this embodiment, the radially inner surface of the impeller housing 3 and the radially inner surface of the shroud 13 are frustoconical shapes, with the inner diameter decreasing as viewed from the axial direction Da1. For example, the region of the radially inner surface of the housing cylinder 31 that is further towards the 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 33 constitute the aforementioned frustoconical inner circumferential surface. Preferably, this inner circumferential surface is similar to the radially outer surface of the hub 11.

[0053] By forming the radial inner side of the impeller housing 3 and the radial inner side of the shroud 13 into the same shape as the radial outer side of the hub 11, the airflow drawn from one axial end of the impeller housing 3 (i.e., the suction port 101) can flow smoothly to the radial outer side of the hub 11.

[0054] Furthermore, since the gap between the blade 12 and the radially inner surface of the impeller housing 3 can be reduced, leakage losses at the blade tip can be reduced. For example, if the flow path between the end of the radially inner surface of the shroud and the end of the radially inner surface of the impeller housing increases sharply, leakage losses at the blade tip may increase. Moreover, due to the increased flow path, secondary flow increases, potentially leading to further leakage losses. In this embodiment, however, 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 housing 3 is relatively small. Therefore, the aforementioned problems are less likely to occur.

[0055] However, the above examples do not preclude the possibility that the radial inner surface of the impeller housing 3 and the radial inner surface of the shroud 13 are not the same (especially similar) frustum-shaped structures as the radial outer surface of the hub 11.

[0056] The wind tunnel housing 4 is a cylindrical structure surrounding at least one axial side (Da1) of the motor 2 and extends along the axial direction (Da). The wind tunnel housing 4 is radially opposed to the motor 2, spaced apart, forming a wind tunnel 40 between the portion of the motor 2 and at least one axial side (Da1). Within this wind tunnel 40, airflow flows in the opposite axial direction (Da2). This airflow enters the wind tunnel 40 from the opposite axial end of the impeller housing 3 and the axial end of the motor 2 (or the impeller 1) via the rotation of the impeller 1, flowing into the wind tunnel 40 at one axial side (Da1), and exiting from the opposite axial end of the wind tunnel 40 to the outside of the air supply device 100. The opposite axial end of the wind tunnel 40 functions as an outlet 102.

[0057] A plurality of stationary blades 41 arranged circumferentially are disposed within the wind tunnel housing 4. That is, the air supply device 100 also includes a plurality of stationary blades 41. The stationary blades 41 extend axially Da and radially, and convert the velocity of the air flowing in from the impeller 1 into pressure. In addition, the wind tunnel housing 4 is supported on the motor 2 via the stationary blades 41. The radially outer end of each stationary blade 41 is connected to the radially inner side of the wind tunnel housing 4. The radially inner end of each stationary blade 41 is connected to the radially outer side of the motor 2 (e.g., its housing).

[0058] <1-1-1. Impeller 1>

[0059] Next, refer to Figures 1A to 3 and Figure 5 The structure of impeller 1 will be described. Figure 5 This is an external view showing an example of the structure of the impeller 1 according to the embodiment.

[0060] The impeller 1 includes a hub 11, multiple blades 12, and a shroud 13. The hub 11, multiple blades 12, and shroud 13 can be made of resin or metal such as Al (aluminum) or its alloys. In this embodiment, the hub 11, multiple blades 12, and shroud 13 are integrally formed, preferably constituting a single component. However, this example does not preclude a structure in which at least a portion of them is separate from other components.

[0061] The hub 11 has a conical shape extending along the axial direction Da. Here, "conical shape" includes both a conical shape with the apex of the cone not cut off and a frustum shape with the apex of the cone cut off. The outer diameter of the hub 11, as viewed from the axial direction Da, decreases as it faces Da1 towards the axial direction. The hub 11 is connected to one axial end of the shaft 21.

[0062] In addition, in this embodiment, such as Figure 5 As shown, the hub 11 is a covered cylindrical shape with a frustum-shaped profile. It should be noted that, in this specification, the shape in which one end of the cylindrical body (e.g., the radial outer surface of the hub 11) is covered by a cover (e.g., the axial end face of the hub 11) is referred to as a "covered cylindrical shape". The 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 located on the rotation axis J of the shaft 21.

[0063] The blades 12 extend radially outward from the radially outer surface of the hub 11, and a plurality of them are arranged circumferentially. That is, a plurality of blades 12 are arranged circumferentially on the radially outer surface of the hub 11. In addition, each blade 12 extends at least along the radially outer surface of the hub 11 in the axial direction Da, for example, extending in the circumferential direction as it extends in the opposite axial direction Da2 (see reference). Figure 5(etc.). However, this example does not exclude a structure in which at least a portion of the blades 12 extend axially in the direction of Da on the radially outer surface of the hub 11. Each blade 12 can rotate together with the shaft 21 about the rotation axis J. Through the rotation of the blades 12, the airflow flows in the opposite axial direction Da2 and radially outward.

[0064] The shield 13 is a cylindrical shape extending at least along the axial direction Da, and surrounds the portion of the blade 12 on one axial side Da1 and the rotation shaft J. The shield 13 is disposed on the portion of the blade 12 on one axial side Da1 and connected to its airfoil (i.e., the radially outer end). In other words, the shield 13 is disposed on the radially inner side of the blade 12 and connected to its airfoil. It should be noted that the shield 13 is neither disposed nor connected to the airfoil (i.e., the radially outer end) of the portion of the blade 12 on the other axial side Da2 (in other words, the radially outer side).

[0065] By arranging a shroud 13 on the axial side of the blade 12 (in other words, the radially inner side), the performance of the air supply device 100 having an impeller 1 with a shroud 13 can be improved.

[0066] 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. Therefore, the deformation of the impeller 1 caused by stress is reduced, and the shroud 13 is less likely to detach from the blades 12.

[0067] Furthermore, it can suppress airflow leakage caused by the gap between the blades 12 and the impeller housing 3, and also suppress uneven distribution of the relative velocity of the airflow between adjacent blades 12 in the circumferential direction. Additionally, compared to a structure where the shroud 13 is disposed on the blades 12 as a whole in the axial direction Da, the total pressure efficiency of the impeller 1 unit can be improved. It should be noted that this total pressure efficiency is the pressure boosting efficiency of the impeller 1 unit calculated based on the total pressure difference between the upstream side (intake side) and the downstream side (exhaust side) of the impeller 1. Through these effects, the air supply device 100 can improve the fluid efficiency of the impeller 1.

[0068] Furthermore, by connecting a portion of the blade 12 (i.e., the portion on one side of the axial direction, Da1) to the cylindrical shroud 13, the stress applied to the boundary portion (or connection portion) between the blade 12 and the shroud 13 can be reduced compared to a structure that connects the entire blade 12 to the shroud 13. Therefore, the shroud 13 is difficult to detach from the blade 12, thus enabling the impeller 1 to have a long service life.

[0069] In addition to homogenizing the relative velocity distribution of the airflow between adjacent blades 12, the airflow velocity distribution discharged from between the impeller 1 and the impeller housing 3 is also homogenized. Therefore, the air supply device 100 can reduce noise generated on the downstream side beyond between the impeller 1 and the impeller housing 3. For example, it can reduce noise (discrete frequency noise, etc.) caused by interference with the stationary blades 41 disposed in the wind tunnel 40.

[0070] like Figure 1A and Figure 1B As shown, the shroud 13 is disposed within the annular opening 30 of the impeller housing 3. Thus, even if the axial component of the centrifugal force generated by the rotation of the impeller 1 acts on the shroud 13, the first surface 301 of the annular opening 30, which faces one axial end of the shroud 13 along the axial direction Da, can prevent the shroud 13 (and the impeller 1 itself) from floating in the axial direction Da1. Furthermore, this also prevents the shroud 13 from detaching from the blades 12 due to the aforementioned component force. Therefore, it is possible to suppress or prevent the shroud 13 from floating up in the impeller 1 of the air supply device 100 and detaching from the blades 12.

[0071] Preferably, within the annular opening 30, the protective cover 13 is approximately opposite to the inner surface of the annular opening 30. In other words, the distances W1 and W2 between the axial ends of the protective cover 13 and the inner surface of the annular opening 30 are smaller than the thickness ds of the protective cover 13 (see reference). Figure 1B Here, the thickness ds of the shield 13 is the interval between the radially outer and radially inner surfaces of the shield 13, in other words, the shortest distance from one side to the other.

[0072] For example, in this embodiment, one axial end of the shield 13 and the inner surface of the annular opening 30 facing the other axial direction Da2 (e.g.) Figure 1A and Figure 1B The axial spacing W1 between the inner wall portion 33 and the other axial end face (the inner wall portion 33) is smaller than the thickness ds of the shield 13. Additionally, the axial spacing W1 between the other axial end face (the radially outer end face) of the shield 13 and the inner surface of the annular opening 30 (e.g., the outer surface) is smaller than the thickness ds of the shield 13. Figure 1A and Figure 1B The radial spacing W2 between the second surface 302) is smaller than the thickness ds of the shield 13.

[0073] This narrows the gap between the shroud 13 and the inner surface of the annular opening 30. Therefore, even if a pressure difference exists between the upstream (intake) and downstream (output) sides of this gap, a portion of the downstream airflow is unlikely to return to the upstream side through this gap. Thus, the reduction in the fluid efficiency of the impeller 1 can be suppressed. However, this example does not preclude structures where W1 ≥ ds, nor does it preclude structures where W2 ≥ ds.

[0074] Preferably, the extension length Ls of the shroud 13 extending at least along the axial direction Da is more than 15% and less than 25% of the extension length Lb of the blade 12 extending at least along the axial direction Da along the radially outer side of the hub 11. For example, the extension length Ls is the shortest distance along the radially inner side of the shroud 13 from one axial end of the shroud 13 to the other axial end (see reference). Figure 1B Additionally, the extension length Lb is the distance along the radial outer end of the blade 12 from one axial end to the other axial end (see reference). Figure 1A ).

[0075] By setting the value to 0.15 ≤ (Ls / Lb) ≤ 0.25, the air supply device 100 can evenly reduce the stress applied to the boundary between the blades 12 and the shroud 13 and improve the fluid efficiency of the impeller 1. Therefore, the air supply device 100 can suppress or prevent the shroud 13 from floating up and detaching from the blades 12 while improving the fluid efficiency of the impeller 1.

[0076] It should be noted that when the extension length Ls of the shroud 13 is less than 15% of the extension length Lb of the blade 12, the effects of homogenizing the relative velocity distribution of the airflow between adjacent blades 12 in the circumferential direction and improving the total pressure efficiency of the impeller 1 are reduced. Therefore, the fluid efficiency of the impeller 1 may not be sufficiently improved. Furthermore, the suppression effect of noise such as broadband noise and discrete frequency noise may be reduced or not achieved.

[0077] Furthermore, when the extension length Ls of the shield 13 is greater than 25% of the extension length Lb of the blade 12, the stress applied to the boundary between the blade 12 and the shield 13 increases. Therefore, the shield 13 may easily detach from the blade 12.

[0078] However, the above examples do not exclude structures where (Ls / Lb) < 0.15, nor do they exclude structures where 0.25 < (Ls / Lb).

[0079] Furthermore, preferably, one axial end of the shield 13 is located axially further to the side Da1 than the axial end of the blade 12. More preferably, the axial width Wa between the axial end of the shield 13 and the axial end of the blade 12 is 10% or more and 30% or less of the axial width Ws of the shield 13 (see reference). Figure 1B For example, the axial width Wa is the interval between one axial end of the shroud 13 and one axial end of the blade 12 on the axial direction Da; in other words, it is the shortest distance between the two as observed radially. The axial width Ws is the interval between one axial end of the shroud 13 and the other axial end on the axial direction Da; in other words, it is the shortest distance between the two as observed radially.

[0080] By setting the value to 0.10 ≤ (Wa / Ws) ≤ 0.30, airflow leakage caused by the gap between the blade 12 and the impeller housing 3 can be more effectively suppressed. Therefore, the relative velocity distribution of the airflow between adjacent blades 12 in the circumferential direction can be made more uniform. Thus, the air supply device 100 can more effectively improve the fluid efficiency of the impeller 1.

[0081] It should be noted that when the axial width Wa is less than 10% of the axial width Ws of the shroud 13, the effects of suppressing airflow leakage and homogenizing the relative velocity distribution of airflow between the blades 12 are reduced. Therefore, it may not be possible to sufficiently improve the fluid efficiency of the impeller 1.

[0082] Furthermore, when the aforementioned axial width Wa is greater than 30% of the axial width Ws of the shroud 13, the shroud 13 is positioned further axially than the hub 11 on the Da1 side. This increases the axial dimension of the impeller 1, potentially allowing for a larger air supply device 100. Alternatively, by shortening the axial width Wb of the blades 12 (refer to...) Figure 1B If the aforementioned axial width Wa is greater than 30% of the axial width Ws of the shroud 13, it will be difficult to deliver airflow through the blades 12. It should be noted that the axial width Wb is the distance between one end of the blade 12 along the axial direction Da and the other end along the axial direction; in other words, it is the shortest distance between the two as observed radially. Therefore, the fluid efficiency of the impeller 1 may be reduced.

[0083] However, the above examples do not exclude structures where one axial end of the shield 13 is located further axially on the opposite side, Da2, than one axial end of the blade 12. Furthermore, the above examples do not exclude structures where (Wa / Ws) < 0.10, nor do they exclude structures where 0.30 < (Wa / Ws).

[0084] <1-2. First variation of the implementation method>

[0085] Next, refer to Figure 6A and Figure 6B The first variation of the implementation method will be described. Figure 6A This is an exploded perspective view of the air supply device 100 of the first modified example. Figure 6B This is an enlarged cross-sectional view showing a structural example of the annular opening 30 in the first modified example. It should be noted that... Figure 6B Corresponding to Figure 1A The portion IB is enclosed by the dashed line. Hereinafter, structures different from the embodiments described above will be described. However, the same reference numerals will be used to label the same components as in the embodiments described above, and descriptions of structures identical to those in the embodiments described above will sometimes be omitted.

[0086] In the first variation, such as Figure 6Aand Figure 6B As shown, the impeller housing 3 also has an annular protrusion 34. The annular protrusion 34 is annular in shape surrounding the rotating shaft J, and extends circumferentially from the radially inner side of the housing cylinder portion 31. The annular protrusion 34 is positioned further axially than the other axial end of the inner wall portion 33, forming an annular opening 30 between it and the other axial end of the inner wall portion 33. 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, they are close to each other, and the axial distance W3 between them in the axial direction Da is smaller than the thickness ds of the shroud 13 (see reference). Figure 6B However, this example does not preclude structures where the aforementioned interval W3 is greater than the thickness ds of the shield 13.

[0087] Furthermore, the impeller housing 3 is composed of multiple parts divided by an imaginary plane containing the rotating shaft J. For example, as Figure 6A As shown, the impeller housing 3 is composed of a housing plate 35 that divides the impeller housing 3 into two parts. However, it is not limited to this. Figure 6A For example, the impeller housing 3 can also be divided into more than three parts. In other words, the housing plates 35 constituting the impeller housing 3 can also be more than three parts.

[0088] When the impeller housing 3 is installed on the impeller 1, each housing piece 35 is installed relative to the impeller 1 from the radially outer side to the radially inner side, clamping the impeller 1 in a radial manner. At this time, the shroud 13 is inserted radially through the divided annular openings 30 of each housing piece 35. Moreover, the circumferentially opposite ends of each housing piece 35 are joined together. The joining method used at this time is not particularly limited, and can be, for example, bonding, press-fitting, threaded connection, fusion, brazing, etc.

[0089] As described above, by mounting the aforementioned components (i.e., housing plates 35) relative to the impeller 1 from the radially outer side to the radially inner side, the impeller 1 can be disposed within the impeller housing 3, and in particular, the shroud 13 can be housed within the annular opening 30 of the impeller housing 3. This structure 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 (e.g., the axial end face of the annular protrusion 34).

[0090] It should be noted that the connection between the shaft 21 and the impeller 1 can be performed before or after the impeller housing 3 is installed on the impeller 1. Furthermore, after the impeller housing 3 is installed on the impeller 1, it is installed and engaged with the wind tunnel housing 4.

[0091] <1-3. Second variation of the implementation method>

[0092] Next, refer to Figure 7A and Figure 7B A second variation of the implementation method will be described. Figure 7A This is an exploded perspective view showing a structural example of the air supply device 100 of the second modified example. Figure 7B This is an enlarged cross-sectional view showing a structural example of the annular opening 30 in the second modified example. It should be noted that... Figure 7B Corresponding to Figure 1A The portion IB enclosed by the dashed line. Hereinafter, structures different from the above-described embodiments and their first variations will be described. However, the same reference numerals will be used to denote the same constituent elements as in the above-described embodiments and their first variations, and descriptions of structures identical to those in the above-described embodiments and their first variations will sometimes be omitted.

[0093] In the second variation, the impeller housing 3 is composed of multiple independent components. For example, such as... Figure 7A and Figure 7B As shown, the impeller housing 3 has a first housing 36 and a second housing 37. The first housing 36 is cylindrical, surrounding at least one axial end of the shroud 13. The second housing 37 is connected to the other axial end of the first housing 36 and surrounds the portion of the impeller 1 on the other axial Da2 side. For example, as... Figure 7A and Figure 7B As shown, the impeller housing 3 is divided into two parts by an imaginary plane perpendicular to the rotation axis J and containing an annular protrusion 34 on one end face. In the impeller housing 3, the portion on one side (Da1) of the plane in the axial direction becomes the first housing 36, and the portion on the other side (Da2) of the plane in the axial direction also becomes the first housing 36.

[0094] Furthermore, in the second variation, the second housing 37 is composed of multiple components divided by an imaginary plane containing the rotation axis J. For example, as... Figure 7A As shown, the second housing 37 is composed of a second housing piece 370 that divides the second housing 37 into two parts. However, it is not limited to this. Figure 7A For example, the second housing 37 can also be divided into more than three parts. In other words, the second housing pieces 370 constituting the second housing 37 can also be more than three parts.

[0095] When the impeller housing 3 is installed on the impeller 1, each of the second housing pieces 370 is installed in this part such that it radially clamps the portion of the impeller 1 that is further axially from the annular protrusion 34 towards the Da2 side, from the radially outer side towards the radially inner side. At this time, the other axial end of the shroud 13 is opposite to one axial end of the annular protrusion 34. Moreover, the circumferentially opposite circumferential ends of each of the second housing pieces 370 are joined together. The joining method used at this time is not particularly limited, and can be, for example, bonding, fusion, brazing, etc.

[0096] Furthermore, when the first housing 36 is installed onto the second housing 37, the first housing 36 is installed such that it covers the portion of the impeller 1 on the axial side Da1 (particularly the shroud 13) from one axial end face of the second housing 37 toward the other axial side Da2. At this time, the shroud 13 is disposed between the other axial end of the inner wall portion 33 of the first housing 36 and the axial end face of the annular protrusion 34 of the second housing piece 370. Thus, the shroud 13 is disposed within the annular opening 30 formed between the other axial end of the inner wall portion 33 and the axial end face of the annular protrusion 34. The other axial end of the first housing 36 engages with one axial end of the second housing 37. The engagement method used is not particularly limited; for example, it can be bonding, press-fitting, threaded connection, fusion welding, brazing, etc.

[0097] As described above, the second housing 37 can be assembled by mounting the aforementioned components (i.e., the second housing piece 370) from the radially outer side toward the radially inner side relative to the Da2 side of the impeller 1. Then, the first housing 36 is mounted from the Da1 side toward the Da2 side of the shroud 13 and engaged with one axial end of the second housing 37, thereby assembling the impeller housing 3. Specifically, the shroud 13 can be housed within the annular opening 30 of the impeller housing 3. This structure is effective, for example, when the inner surface of the annular opening 30 has a surface opposite the other axial end of the shroud 13 along the axial Da direction.

[0098] <2. Remarks>

[0099] The embodiments of this utility model have been described above. It should be noted that the above embodiments are merely examples, and those skilled in the art will understand that various modifications can be made to the combination of its constituent elements and processes, and such modifications are also within the scope of this utility model.

[0100] <3. Summary>

[0101] The following is a summary description of the implementation methods described so far.

[0102] For example, the air supply device disclosed in this specification is configured as follows (first structure), the air supply device comprising:

[0103] An impeller that is able to rotate about a rotating shaft that extends along the axial direction;

[0104] A motor having a shaft capable of rotating together with the impeller; and

[0105] The impeller housing is a cylindrical shape extending axially and surrounds and houses the impeller.

[0106] The impeller has:

[0107] The hub is a conical shape whose outer diameter decreases as it is axially oriented and is connected to one axial end of the shaft.

[0108] A plurality of blades, extending radially outward from the radially outer surface of the hub and arranged circumferentially, extend at least axially along the radially outer surface of the hub; and

[0109] A protective cover, which is at least cylindrical in shape extending axially, surrounds a portion of the blade on one axial side and the rotation shaft, and is connected to the radially outer end of the portion of the blade on one axial side.

[0110] A circumferentially extending annular opening is provided on the radially inner surface of the impeller housing.

[0111] The protective cover is disposed within the annular opening.

[0112] The air supply device of the first structure described above can also be of the following structure (second structure), wherein,

[0113] The extension length of the shroud extending at least axially is more than 15% and less than 25% of the extension length of the blade extending at least axially along the radial outer side of the hub.

[0114] Alternatively, the air supply device of the first or second structure described above can also be of the following structure (third structure), wherein,

[0115] One axial end of the shield is located further axially than the blade.

[0116] The axial width between one axial end of the shield and one axial end of the blade is more than 10% and less than 30% of the axial width of the shield.

[0117] Alternatively, the air supply device of any of the first to third structures mentioned above can also be the following structure (fourth structure), wherein,

[0118] The distance between the axial end of the shield and the inner surface of the annular opening is smaller than the thickness of the shield.

[0119] Alternatively, the air supply device of any of the first to fourth structures mentioned above can also be the following structure (fifth structure), wherein,

[0120] The inner surface of the annular opening has:

[0121] The first face is annular in shape, extending radially and axially opposite one end of the shield; and

[0122] The cylindrical second surface is radially opposed to the other axial end of the shield.

[0123] The second surface extends axially or radially outward as it moves toward the other side of the axial direction.

[0124] Alternatively, the air supply device of any of the first to fifth structures mentioned above can also be the following structure (sixth structure), wherein,

[0125] The impeller housing is composed of multiple parts divided by an imaginary plane containing the rotating shaft.

[0126] Alternatively, the air supply device of any of the first to fifth structures mentioned above can also be the following structure (seventh structure), wherein,

[0127] The impeller housing has:

[0128] A cylindrical first housing surrounding at least one axial end of the shield; and

[0129] The second housing is connected to the other axial end of the first housing and surrounds the portion of the impeller on the other axial side.

[0130] The second housing is composed of multiple components divided by an imaginary plane including the rotation axis.

[0131] Alternatively, the air supply device of any of the structures in the first to seventh categories mentioned above can also be the following structure (eighth structure), wherein,

[0132] The radially inner surface of the impeller housing and the radially inner surface of the shroud are frustoconical shapes, with the inner diameter decreasing as viewed from the axial direction.

[0133] Furthermore, the vacuum cleaner disclosed in this specification is configured as a structure having an air supply device having any of the structures of the first to eighth described above (ninth structure).

[0134] Industrial availability

[0135] This invention is useful for devices used to deliver suction fluid.

Claims

1. An air supply device, characterized by comprising: Possessing: an impeller capable of rotating around a rotation shaft extending in an axial direction; a motor having a shaft capable of rotating together with the impeller; and an impeller housing which is a cylindrical shape extending in an axial direction and which surrounds and houses the impeller, the impeller has: a hub which is a conical shape whose outer diameter observed in an axial direction becomes smaller as it goes toward the axial direction and which is connected to an axial one end portion of the shaft; a blade which extends from a radially outer side of the hub toward a radially outer side and which is arranged with a plurality of blades in a circumferential direction and which extends at least in an axial direction along a radially outer side surface of the hub; and a shroud which is a cylindrical shape extending at least in an axial direction and which surrounds a portion of the axial one side of the blade and the rotation shaft and which is connected to a radially outer end portion of the portion of the axial one side of the blade, a circular ring opening portion extending in a circumferential direction is arranged on a radially inner side surface of the impeller housing, the shroud is arranged inside the circular ring opening portion.

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

3. The air supply device according to claim 1, wherein an axial one end portion of the shroud is positioned at a position further toward the axial direction than the blade, an axial width between the axial one end portion of the shroud and an axial one end portion of the blade is 10% or more and 30% or less of an axial width of the shroud.

4. The air supply device according to claim 1, wherein a gap between an axial end portion of the shroud and an inner surface of the circular ring opening portion is smaller than a thickness of the shroud.

5. The air supply device according to claim 1, wherein the inner surface of the circular ring opening portion has: a first surface of a circular ring shape which expands in a radial direction and which is opposed to the axial one end portion of the shroud in an axial direction; and a second surface of a cylindrical shape which is opposed to an axial other end portion of the shroud in a radial direction, the second surface extends in an axial direction or extends toward a radially outer side as it goes toward an axial other direction.

6. The air supply device according to claim 1, wherein the impeller housing is composed of a plurality of members which are divided by an imaginary plane including the rotation shaft.

7. The air supply device according to claim 1, wherein the impeller housing has: a first housing of a cylindrical shape which surrounds at least the axial one end portion of the shroud; and a second housing which is connected to an axial other end portion of the first housing and which surrounds a portion of the axial other side of the impeller, the second housing is composed of a plurality of members which are divided by an imaginary plane including the rotation shaft.

8. The air supply device according to claim 1, wherein a radially inner side surface of the impeller housing and a radially inner side surface of the shroud are a conical frustum shape whose inner diameter observed in an axial direction becomes smaller as it goes toward the axial direction.

9. A dust collector, wherein the air supply device according to any one of claims 1 to 8 is possessed. ​

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