Electric blower and vacuum cleaner equipped with it

Abstract

We provide technology to make electric blowers smaller and lighter. [Solution] The electric blower 100 of the present invention comprises a rotating shaft 51 provided on a rotor core 55, an impeller 10 fixed to the rotating shaft 51, a stator 60 arranged on the outer circumferential surface of the rotor core 55 via an air gap and equipped with a coil 63, and an upstream housing 20 arranged downstream of the impeller 10 and equipped with a first axial flow diffuser blade 23. The stator 60 is provided with a stator core 61 having a plurality of teeth 81 around which the coil 63 is wound. The upstream housing 20 and the stator 60 are provided with bolts 80 that fix them in the axial direction. The bolts 80 are arranged radially outward of the coil 63 and radially inward of the upstream inner wall 21 of the upstream housing 20 which is equipped with the first axial flow diffuser blade 23 radially outward, and the stator core 61 is provided with a notch 67 that extends axially and through which the bolts 80 pass.

Description

Technical Field

[0001] The present invention relates to an electric blower and a vacuum cleaner provided with the same.

Background Art

[0002] Cordless stick-type vacuum cleaners and self-propelled vacuum cleaners, for which demand has been rapidly increasing in recent years, are required to be smaller and lighter from the viewpoint of improving operability. To reduce the size and weight of a vacuum cleaner, it is effective to reduce the size and weight of the electric blower, which accounts for a large portion of the volume and weight among the components constituting the vacuum cleaner. Therefore, electric blowers using DC brushless motors that have small size, high output and high efficiency performance are used in vacuum cleaners.

[0003] For example, Patent Document 1 discloses a blower device including an impeller, a motor arranged below the impeller to rotate the impeller, a motor housing provided on the outer diameter side of a stator to accommodate the stator of the motor, and a fan casing that accommodates the impeller and the motor housing.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of Invention

Problems to be Solved by the Invention

[0005] From the viewpoint of reducing the size of the electric blower, it is required to reduce the diameters of the impeller, the motor, and the motor housing to reduce the diameter of the fan casing. In particular, since the diameter of the fan casing is large at the portion where the motor is accommodated, it is required to reduce the diameter of the motor accommodating portion.

[0006] However, the technology described in Patent Document 1 has the problem that the diameter of the motor housing in the fan casing becomes large because a motor housing for fixing is located on the outer diameter side of the motor stator. If the motor is made smaller in order to reduce the diameter of the motor housing in the fan casing, there is a concern that it will lead to a decrease in motor output and a deterioration in efficiency. Furthermore, although removing the motor housing is also considered to be an effective way to reduce the diameter of the motor housing in the fan casing, there is a problem that the motor housing cannot be simply removed because it would no longer be possible to fix the motor to the fan casing.

[0007] The objective of the present invention is to solve the above-mentioned problems and to provide a technology that reduces the size and weight of an electric blower while maintaining its performance. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides an electric blower comprising: a rotor; a rotating shaft provided on the rotor; an impeller fixed to the rotating shaft; a stator disposed on the outer circumferential surface of the rotor via an air gap and equipped with a coil; and a housing disposed downstream of the impeller and equipped with diffuser blades, wherein the stator is equipped with a stator core having a plurality of teeth around which the coil is wound, and the present invention provides bolts for fixing the housing and the stator in the axial direction, wherein the bolts are disposed radially outward from the coil and radially inward from the inner wall of the housing equipped with the diffuser blades radially outward, and the stator core is equipped with an insertion portion extending axially for passing the bolts. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide a technology that makes electric blowers smaller and lighter while maintaining their performance. [Brief explanation of the drawing]

[0010] [Figure 1]This is an external view of an electric blower 100 according to Embodiment 1 of the present invention. [Figure 2] This is a longitudinal cross-sectional view of an electric blower 100 according to Embodiment 1 of the present invention. [Figure 3] This is an exploded perspective view of the electric blower 100 according to Embodiment 1 of the present invention. [Figure 4A] This is a side view showing a portion of the upstream housing 20 according to Embodiment 1 of the present invention. [Figure 4B] This is a cross-sectional view of the downstream housing 30 according to Embodiment 1 of the present invention. [Figure 5A] This is a side view of the stator 60 according to Embodiment 1 of the present invention. [Figure 5B] This is a perspective view of the stator 60 according to Embodiment 1 of the present invention. [Figure 6] This is an exploded perspective view showing a method for fixing the upstream housing 20 and stator 60 according to Embodiment 1 of the present invention. [Figure 7] This is a side view showing a portion of the fan casing 1, upstream housing 20, and downstream housing 30 of an electric blower. [Figure 8] This is a cross-sectional view taken along the line VIII-VIII in Figure 7. [Figure 9A] This is a cross-sectional view of the motor 200 according to Example 1 as a comparative example, cut in a direction perpendicular to the axial direction. [Figure 9B] This is an enlarged view of section IXB in Figure 9A. [Figure 10A] This is a cross-sectional view of the motor 200 according to Embodiment 2 of the present invention, cut in a direction perpendicular to the axial direction. [Figure 10B] This is an enlarged view of section XB in Figure 10A. [Figure 11A] This is a cross-sectional view of the motor 200 according to Embodiment 3 of the present invention, cut in a direction perpendicular to the axial direction. [Figure 11B] This is an enlarged view of section XIB in Figure 11A. [Figure 12A] This is a cross-sectional view of the motor 200 according to Embodiment 4 of the present invention, cut in a direction perpendicular to the axial direction. [Figure 12B] This is an enlarged view of section XIIB in Figure 12A. [Figure 13] It is a perspective view showing the appearance of the electric vacuum cleaner 300 according to Embodiment 5 of the present invention. [Mode for Carrying Out the Invention]

[0011] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, the same reference numerals are assigned to the same elements throughout all the drawings. In addition, descriptions of parts having the same function will be omitted. The configurations described below are merely examples, and are not intended to limit the implementation modes of the present invention to the following specific modes. [Embodiment]

[0012] [Configuration of Electric Blower 100] Figure 1 is an external view of the electric blower 100 according to Embodiment 1 of the present invention. Figure 2 is a longitudinal sectional view of the electric blower 100 according to Embodiment 1 of the present invention. Figure 3 is an exploded perspective view of the electric blower 100 according to Embodiment 1 of the present invention.

[0013] The electric blower 100 includes: a motor having a rotor (rotor core 55) and a stator 60; an impeller 10 fixed to a rotating shaft 51 provided on the rotor (rotor core 55) and driven by the motor; an upstream bearing 52 and a downstream bearing 53 which are located between the impeller 10 and the rotor (rotor core 55) and serve as bearings that rotatably support the rotating shaft 51; a bearing holding portion 54 that covers the outer peripheries of the upstream bearing 52 and the downstream bearing 53; a frame 70 arranged on the outer peripheral side of the bearing holding portion 54 and covering a part of the bearings; a housing 3 located radially outward of the frame 70 and covering a part of the frame 70; a fan casing 1 fixed to the housing 3 to cover the impeller 10 and having an air suction port 90 through which air flows in; and a bearing cap 4 arranged radially outward of the frame 70 and covering a part of the frame 70. In this embodiment, the rotor assembly 50 is constituted by the rotor core 55, the rotating shaft 51, the upstream bearing 52, the downstream bearing 53, the bearing holding portion 54, and the impeller 10. The bearing holding portion 54 and the frame 70 of this embodiment are made of an aluminum alloy or a magnesium alloy.

[0014] Furthermore, the rotor core 55 is composed of permanent magnets having multiple magnetic poles and is fixed to the outer surface of the rotating shaft 51. A balance ring 56 is also fixed to the axial downstream side of the rotor core 55. Part of the rotor assembly 50 is enclosed within the stator 60 (stator core 61).

[0015] Housing 3 is located downstream of the impeller 10 and is equipped with diffuser blades. Housing 3 also consists of an upstream housing 20 that secures the fan casing 1 and a downstream housing 30 that is fixed to the upstream housing 20.

[0016] The bearing consists of an upstream bearing 52 located on the impeller 10 side, a downstream bearing 53 located on the rotor (rotor core 55) side, and a bearing retaining portion 54 that covers the upstream bearing 52 and the downstream bearing 53.

[0017] As shown in Figures 1 and 2, the fan casing 1 is molded from resin or the like and has a hollow conical shape. The fan casing 1 has an open structure at its upper and lower axial ends and accommodates part or all of the impeller 10. The fan casing 1 also encloses part or all of the leading edge 23a of the first axial diffuser blade 23 of the upstream housing. The fan casing 1 is attached to the upstream housing 20 so as to cover the impeller 10 from the axial upper side.

[0018] The electric blower 100 is positioned by inserting the fitting portion 2 of the fan casing 1 into the claw projection 25 of the upstream housing 20. The fan casing 1 and the upstream housing 20 are fixed together by injecting adhesive or the like into the fitting portion 2, while also preventing fluid leakage. The electric blower 100 also includes a downstream housing 30 mounted on the downstream side of the upstream housing 20. The downstream housing 30 is fixed to the upstream housing 20 by fitting the claw projection 26 of the upstream housing 20 into the fitting hole 34 of the downstream housing 30. The diameter of the electric blower 100 in this embodiment is 40 mm or less.

[0019] <Configuration of Upstream Housing 20> Figure 4A is a side view of a portion of the upstream housing 20 according to Embodiment 1 of the present invention. The upstream housing 20 includes a disc-shaped mounting portion 24 that includes a plane perpendicular to the axial direction, an upstream inner wall 21 (hub) extending downward in the axial direction from the outer circumference of the mounting portion 24, an upstream outer wall 22 (shroud) provided radially outside the upstream inner wall 21 with a gap in between, and a first axial flow diffuser blade 23 that connects the upstream inner wall 21 and the upstream outer wall 22, and slows down the flow from the impeller and increases the pressure. The first axial flow diffuser blade 23 has an inclination θ1 that is inclined circumferentially with respect to the axial direction.

[0020] In other words, the upstream housing 20 is located on the impeller 10 side and radially outward from the frame 70, and is equipped with a first axial diffuser blade 23 having an inclination θ1 in the circumferential direction between the upstream inner wall 21 and the upstream outer wall 22 located radially outward from the upstream inner wall 21.

[0021] The outer circumferential surface of the upstream outer wall 22 is provided with a claw projection 25 that protrudes radially outward for connection with the fan casing 1, and a claw projection 26 that protrudes radially outward for connection with the downstream housing 30. In addition, an exhaust opening 73 that opens radially outward is formed on the downstream side of the upstream inner wall 21.

[0022] <Configuration of Downstream Housing 30> Figure 4B is a cross-sectional view of a downstream housing 30 according to Embodiment 1 of the present invention. The downstream housing 30 comprises a downstream outer wall 31 and a second axial flow diffuser blade 32 located radially inward of the downstream outer wall 31, which decelerates the fluid and increases the pressure. The second axial flow diffuser blade 32 has an inclination θ2 that is inclined circumferentially with respect to the axial direction.

[0023] In other words, the downstream housing 30 is located on the side opposite the impeller of the upstream housing 20 and radially outward from the stator core 61, and is equipped with a second axial flow diffuser blade 32 having an inclination θ2 in the circumferential direction between the stator core 61 and the downstream outer wall 31 located radially outward from the stator core 61. The radially inward side of the second axial flow diffuser blade 32 is in contact with the stator core 61.

[0024] The upstream housing 20 and the downstream housing 30 are fixed together by fitting the claw projection 26 of the upstream housing 20 into a fitting hole 34 provided in the downstream projection 33 of the downstream housing 30. However, in addition to the fitting of the claw projection 26 and the fitting hole 34, the upstream housing 20 and the downstream housing 30 may also be fixed together using adhesive or the like. As a result, the upstream outer wall 22 and the downstream outer wall 31 become one and form a substantially thick cylindrical outer wall 41 (Figure 2) that extends in the axial direction. The outer wall 41 faces the radially outer side of the exhaust opening 73 of the upstream housing 20 with a gap in between.

[0025] In this embodiment, the housing 3 is divided into an upstream housing 20 and a downstream housing 30, but it may also be constructed as a single unit. The materials used for the upstream housing 20 and the downstream housing 30 may include resin or an aluminum alloy.

[0026] <Configuration of bearing cap 4> As shown in Figure 2, the bearing cap 4 is positioned on the impeller 10 side of the upstream housing 20 and frame 70, and is provided at an angle such that its diameter increases from the impeller 10 side towards the upstream housing 20 side, connecting to the upstream inner wall 21 of the upstream housing 20. The upstream inner wall 21 of the upstream housing 20, the bearing cap 4, and the fan casing 1 form a vaneless diffuser flow path 29 that guides the flow from the impeller 10 to the first axial flow diffuser blade 23. The vaneless diffuser flow path 29 is formed to be inclined radially outward from the outer diameter of the impeller 10.

[0027] Furthermore, the bearing cap 4 is fixed to the upstream housing so as to be in contact with the frame 70. The bearing cap 4 may be composed of multiple parts, for example, semicircular parts divided in the circumferential direction, and is held in the housing 3 and fixed by adhesive or the like.

[0028] <Configuration of Stator 60> Figure 5A is a side view of a stator 60 according to Embodiment 1 of the present invention. Figure 5B is a perspective view of a stator 60 according to Embodiment 1 of the present invention. The stator 60 comprises a stator core 61, an insulator 62 disposed on the stator core 61, a coil 63 wound around the insulator 62, a terminal 64, and a terminal holding portion 65 for holding the terminal 64. The stator core 61 comprises an annular yoke 86 forming the outer circumference of the stator core 61 and a plurality of teeth 81 extending radially inward from the yoke 86 (see Figure 8). Slots 82 are formed between adjacent teeth 81, in which the coil 63 is placed (see Figure 8). The insulator 62 is disposed in the slots 82 so as to cover the teeth 81 (see Figure 8).

[0029] The insulator 62 is divided into an upstream insulator 62a and a downstream insulator 62b in a plane perpendicular to the rotation axis 51. Terminals 64 are inserted into the terminal holding portion 65 of the insulator 62, and the coil 63 and terminals 64 are electrically connected. On the inner circumference side of the stator core 61, the outer surface of the rotor core 55 is positioned opposite the inner surface of the stator core 61 via an air gap 83 (see Figure 8). When a three-phase AC voltage is supplied from terminal 64 to coil 63, a rotating magnetic field is generated in the stator 60, and rotational torque is generated in the rotor core 55. The stator core 61 is constructed by laminating electrical steel sheets mainly composed of iron. The upstream insulator 62a and the downstream insulator 62b are made of resin such as polyethylene terephthalate (PET). The coil 63 is made of a conductive material such as copper or aluminum alloy.

[0030] The insulator 62 has multiple protrusions 66 that project axially away from the stator core 61 and are arranged in a circumferential direction. In addition, an axially communicating gap 66a is formed between adjacent protrusions 66 of the insulator 62. The coil 63 is wound around multiple teeth 81 (see Figure 8) via the insulator 62. The coil 63 is wound radially outward from the protrusions 66 of the insulator 62.

[0031] Figure 6 is an exploded perspective view showing a method for fixing the upstream housing 20 and stator 60 according to Embodiment 1 of the present invention. Multiple notches 67 (insertion portions) extending in the axial direction are formed on the radially outer side of the stator core 61 for passing bolts 80 through. In this embodiment, the notches 67 are formed along the axial direction of the stator core 61 and are cut out from the radially outer side to the radially inner side, with the radially outer side open.

[0032] Multiple fixing holes 27 are formed on the end of the upstream inner wall 21 of the upstream housing 20 that is opposite the impeller (towards the stator core 61), extending axially and into which bolts 80 are screwed. To fix the upstream housing 20 and the stator 60, the upstream housing 20 and the stator core 61 are brought into contact, the fixing holes 27 of the upstream housing 20 are aligned with the notches 67 of the stator core 61, the bolts 80 are inserted through the notches 67 of the stator core 61, and the tips of the bolts 80 are inserted into the fixing holes 27 and screwed in. In this way, the upstream housing 20 and the stator 60 are fixed axially by the bolts 80.

[0033] The bolt 80 is positioned radially outward from the coil 63. Since the diameter of the bolt 80 is greater than the radial thickness of the upstream inner wall 21 of the upstream housing 20, the radial thickness around the fixing hole 27 formed in the upstream inner wall 21 is greater than the radial thickness of the rest of the upstream inner wall 21. The radially outward side of the upstream inner wall 21 is provided with the first axial flow diffuser blade 23 and a vaneless diffuser flow path 29 is formed thereon. If the radially outward side of the upstream inner wall 21 protrudes to form the fixing hole 27, the protruding portion will create wind resistance in the vaneless diffuser flow path 29. Therefore, in this embodiment, the radially inward side of the upstream inner wall 21 is made to protrude to form the fixing hole 27. In other words, the bolt 80 that fixes the upstream housing 20 and the stator 60 is positioned radially inward from the radially outward surface of the upstream inner wall 21 of the upstream housing 20.

[0034] According to the embodiment described above, since the stator 60 is fixed to the upstream housing 20 using bolts 80, a motor housing or the like for fixing the stator is not required on the radially outer side of the stator 60, thus the diameter of the electric blower can be reduced. This makes it possible to provide a small and lightweight electric blower.

[0035] Furthermore, according to this embodiment, since the bolt 80 is positioned radially outward from the coil 63 and radially inward from the upstream inner wall 21 of the upstream housing 20, it is possible to suppress the bolt 80 from protruding into the vaneless diffuser flow path 29 and creating air resistance.

[0036] <Airflow inside the electric blower 100> Next, the airflow inside the electric blower 100 will be explained using Figures 2, 7, and 8. Figure 7 is a side view of a portion of the fan casing 1, upstream housing 20, and downstream housing 30 of the electric blower. Figure 8 is a cross-sectional view taken along the line VIII-VIII in Figure 7.

[0037] When a three-phase AC voltage is supplied from terminal 64 to coil 63, a rotating magnetic field is generated in the stator 60, and rotational torque is generated in the rotor core 55. As the rotor core 55 rotates, the rotating shaft 51 and impeller 10 connected to the rotor core 55 rotate. As the impeller 10 rotates, a main flow F1 is generated from the upstream side to the downstream side.

[0038] Mainstream F1 is formed when air flows in from the air intake port 90 of the fan casing 1 and into the impeller 10. In the case of a mixed-flow impeller, the incoming air is pressurized by the blades within the impeller 10, adding a radial component to the flow drawn in from the axial direction, and generating a flow that is inclined from the axial direction and has a radial component in addition to the axial direction. At the impeller outlet 14, the flow becomes a combination of the rotational and axial components and flows out from the impeller 10. The mainstream F1 that flows out from the impeller 10 flows into the vaneless diffuser flow path 29.

[0039] The main flow F1 that enters the vaneless diffuser flow path 29 is gently redirected along the upstream outer wall 22 and upstream inner wall 21 within the vaneless diffuser flow path 29 to the same diameter as the outermost diameter of the stator core 61, and the flow is decelerated due to the gradual increase in the flow path cross-sectional area within the vaneless diffuser flow path 29. Subsequently, as it passes through the first axial flow diffuser blade 23 and the second axial flow diffuser blade 32, the rotational velocity component is converted into a straight-line component and decelerated, causing the static pressure to rise and the air to be exhausted from the exhaust port 91, which is the end of the downstream housing 30. The main flow F1 flows at a circumferential inclination due to the first axial flow diffuser blade 23 and the second axial flow diffuser blade 32. That is, a first flow path is formed in the impeller 10, the first axial flow diffuser blade 23 and the second axial flow diffuser blade 32 through which the air (main flow F1) entering from the air intake port 90 flows. In this embodiment, in order to form a first flow path through which such air (mainstream F1) flows, the outer diameter of the stator 60 (stator core 61) is made smaller than the outer diameter of the second axial flow diffuser blade 32, and the outer diameter of the impeller 10 is made smaller than the outer diameter of the stator 60 (stator core 61).

[0040] Here, the flow at the outlet of the first axial flow diffuser blade 23 is a high-speed flow and has a lower pressure compared to the exhaust port 91. The exhaust opening 73 of the upstream housing 20 opens toward the first flow path and is close to the outlet of the first axial flow diffuser blade 23, so its position is equivalent to that of the outlet of the first axial flow diffuser blade 23. Therefore, due to the Venturi effect, a cooling flow F2 is generated that flows from the exhaust port 91 through the inside of the motor and toward the exhaust opening 73 of the upstream housing 20. In other words, air (cooling flow F2) passes between the exhaust port 91, the inside of the motor, and the exhaust opening 73 of the upstream housing 20, forming a second flow path that merges with the first flow path.

[0041] The impeller 10, the rotating shaft 51, and the bearing holder 54 are made of aluminum or magnesium alloy, which have high thermal conductivity. When the impeller 10 rotates, the impeller 10 is cooled by the main flow F1, and the rotating shaft 51, the upstream bearing 52, and the downstream bearing 53 are cooled by heat transfer.

[0042] Next, let's explain the cooling flow F2. The cooling flow F2 is drawn in from the exhaust port 91 of the downstream housing 30 and flows towards the exhaust opening 73 of the upstream housing 20, passing through the stator core 61, the coils 63 arranged in the circumferential direction, and so on.

[0043] The cooling flow F2 is then exhausted from the exhaust opening 73 of the upstream housing 20 between the stator core 61 and the downstream outer wall 31 of the downstream housing 30. The fluid exhausted between the stator core 61 and the downstream outer wall 31 of the downstream housing 30 flows toward the exhaust port 91, merges with the main flow F1 upstream of the second axial flow diffuser blade 32 or within the inter-blade flow path of the second axial flow diffuser blade 32, and is exhausted at the exhaust port 91.

[0044] In other words, the airflow rate passing through the second axial-flow diffuser blade 32 is increased by the airflow rate of the cooling flow F2 compared to the airflow rate of the main flow F1 passing through the first axial-flow diffuser blade 23. This increase in airflow rate makes it possible to improve efficiency by reducing flow separation in the second axial-flow diffuser blade 32.

[0045] As the cooling flow F2 moves from the exhaust port 91 towards the exhaust opening 73 of the upstream housing 20, it branches into the air gap 83 and slot 82 (a flow path composed of adjacent coils 63), cooling the stator core 61, rotor core 55, coils 63, downstream bearing 53, and bearing holder 54, before colliding with the large-diameter section 75 of the frame 70. The cooling flow F2 that collides with the large-diameter section 75 of the frame 70 is cooled by heat exchange with the frame 70 and then moves towards the exhaust opening 73 of the upstream housing 20. After cooling, the cooling flow F2 merges with the main flow F1, where heat exchange occurs, and the mixed flow is exhausted to the outside, thereby cooling the motor.

[0046] In this configuration, there is no flow redirection or guide to draw cooling air into the motor; the motor is cooled by the suction of airflow due to the Venturi effect, resulting in low pressure loss and enabling high efficiency of the electric blower. Furthermore, because there is no guide for the cooling air, high blower efficiency can be maintained even at non-design points, enabling high efficiency over a wide operating range.

[0047] Next, the effects of the electric blower 100 will be explained. The electric blower 100 has a frame 70 fixed to the upstream housing 20, and a stator 60 fixed to the upstream housing 20 to which the frame 70 is fixed, and the outer circumference of the stator core 61 of the upstream housing 20 and the stator 60 form part of the first flow path, so the external dimensions of the electric blower 100 can be reduced and the electric blower 100 can be made smaller.

[0048] Furthermore, the downstream housing 30 is fixed to the upstream housing 20, and the downstream housing 30 and the outer circumference of the stator core 61 of the stator 60 form part of the first flow path connected from the upstream housing 20 side. The stator core 61 has a notch 67 formed along the axial direction, which is cut out from the radially outer side to the radially inner side, leaving the radially outer side open. The bolts 80 that fix the upstream housing 20 and the stator 60 are inserted into the notch 67 and screwed into the upstream housing 20, but the fixing bolts 80 are not exposed to the first flow path, so the flow loss of the main flow F1 flowing through the first flow path can be reduced. In addition, since the notch 67 is formed so that the radially outer side of the stator core 61 is open, the stator core 61 can be made lighter.

[0049] In this embodiment, the stator core 61 is provided with a notch 67 that is open on the radially outer side, but the stator core 61 may also be provided with a through hole that penetrates axially and is not open on the radially outer side. [Examples]

[0050] Next, Embodiment 2 of the present invention will be described using Figures 9A to 10B. Components common to Embodiment 1 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0051] Figure 9A is a cross-sectional view of the motor 200 according to Example 1 as a comparative example, cut in a direction perpendicular to the axial direction. Figure 9B is an enlarged view of section IXB in Figure 9A. In Figures 9A and 9B, only the motor 200, which consists of the rotor assembly 50 and the stator 60, is shown.

[0052] As described in Example 1, the stator core 61 has a notch 67 formed along the axial direction, which is cut out from the radially outer side toward the radially inner side, with the radially outer side open. The direction of opening of the notch 67 coincides with the radial direction r of the motor 200 (electric blower 100).

[0053] Furthermore, the main flow F1 flows at a circumferential inclination due to the first axial diffuser blade 23 and the second axial diffuser blade 32. The main flow F1, inclined circumferentially by the second axial diffuser blade 32, flows between the downstream outer wall 31 of the downstream housing 30 and the radially outer surface of the stator core 61. Since the notch 67, which is provided so that the radially outer surface of the stator core 61 is open, is exposed to the flow path of the main flow F1, a portion of the main flow F1 becomes a separated flow Fs and flows into the notch 67, which can increase windage losses and potentially lead to a decrease in the performance of the electric blower 100. Means to solve this will be described.

[0054] Figure 10A is a cross-sectional view of the motor 200 according to Embodiment 2 of the present invention, cut in a direction perpendicular to the axial direction. Figure 10B is an enlarged view of section XB in Figure 10A. In Figures 10A and 10B, only the motor 200, which consists of a rotor assembly 50 and a stator 60, is shown.

[0055] In this embodiment, the opening direction of the notch 67 is inclined at a predetermined angle (angle of inclination θn) in the circumferential direction with respect to the radial direction r of the motor 200 (electric blower 100). The opening direction (angle of inclination) of the notch 67 is the same as the direction of inclination θ1 in the circumferential direction of the first axial flow diffuser blade 23 and the direction of inclination θ2 in the circumferential direction of the second axial flow diffuser blade 32. In other words, the opening direction (angle of inclination) of the notch 67 is oriented in the direction of the flow of the main flow F1 with respect to the radial direction r of the motor 200 (electric blower 100).

[0056] According to the embodiment described above, it is possible to suppress the amount of separation flow Fs flowing into the notch 67, thereby suppressing windage loss and preventing performance degradation of the electric blower 100. This makes it possible to provide an electric blower that is compact, lightweight, and has suppressed performance degradation. [Examples]

[0057] Next, Embodiment 3 of the present invention will be described using Figures 11A and 11B. Components common to Embodiments 1 and 2 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0058] Figure 11A is a cross-sectional view of the motor 200 according to Embodiment 3 of the present invention, cut in a direction perpendicular to the axial direction. Figure 11B is an enlarged view of section XIB in Figure 11A. In Figures 11A and 11B, only the motor 200, which consists of the rotor assembly 50 and the stator 60, is shown.

[0059] In Example 3, the difference from Examples 1 and 2 is that the corners S of the notch 67 are chamfered. In this example, the corners S of the notch 67 are processed into an arc shape with an R chamfer, but the corners S of the notch 67 may also be processed into a planar shape with a C chamfer.

[0060] According to this embodiment, in addition to the effects of Embodiment 2, the flow velocity at the outlet portion of the notch 67 can be made uniform when the separated flow Fs flowing into the notch 67 flows out. This suppresses the generation of turbulence and reduces wind loss. Furthermore, according to this embodiment, it is possible to provide an electric blower that is compact, lightweight, and has suppressed performance degradation. [Examples]

[0061] Next, Embodiment 4 of the present invention will be described using Figures 12A and 12B. Components common to Embodiments 1 to 3 are denoted by the same reference numerals, and their detailed descriptions are omitted.

[0062] Figure 12A is a cross-sectional view of the motor 200 according to Embodiment 4 of the present invention, cut in a direction perpendicular to the axial direction. Figure 12B is an enlarged view of section XIIB in Figure 12A. In Figures 12A and 12B, only the motor 200, which consists of the rotor assembly 50 and the stator 60, is shown.

[0063] In Figures 12A and 12B, if W is the minimum width of the teeth 81 of the stator core 61, and D is the width at which the distance between the bolt 80 and the stator core 61 located radially inward from the bolt 80 is minimized, then the position of the notch 67 and the inclination angle θn of the notch 67 are provided at a position that satisfies the relationship D ≥ W / 2. This makes it possible to suppress magnetic saturation in the portion of width D at which the distance between the bolt 80 and the stator core 61 located radially inward from the bolt 80 is minimized when the motor 200 is driven.

[0064] According to the embodiments described above, it is possible to suppress windage loss by suppressing the amount of separated flow Fs flowing into the notch 67, and also to suppress the deterioration of the motor characteristics of the motor 200, thereby suppressing the performance degradation of the electric blower 100. As a result, it is possible to provide an electric blower that is small, lightweight, and has suppressed performance degradation.

[0065] In the above-described embodiments 1 to 4, the bolts 80 are positioned radially outward from the teeth 81 of all stator cores 61. This is an example of an arrangement to ensure magnetic balance. [Examples]

[0066] Next, Example 5 of the present invention will be described using Figure 13. Example 5 describes the configuration of an electric vacuum cleaner 300 equipped with the electric blower 100 described in Examples 1 to 4.

[0067] <Configuration of the 300-size vacuum cleaner> Figure 13 is a perspective view showing the external appearance of the vacuum cleaner 300 according to Embodiment 5 of the present invention. The electric blower 100 described in Embodiments 1 to 4 is suitable for mounting on the vacuum cleaner 300, for example, to obtain suction power.

[0068] As shown in Figure 13, the electric vacuum cleaner 300 includes a vacuum cleaner body 301 equipped with an electric blower 100 and a dust collection unit 302 that contains dust collected by the suction force generated by the electric blower 100, an extension pipe 306 with one end connected to the vacuum cleaner body 301 and communicating with the dust collection unit 302, and a suction nozzle 307 connected to the other end of the extension pipe 306. The vacuum cleaner body 301 also includes a battery unit 303 as a power source, a grip section 304, and a switch section 305 provided on the grip section 304 for turning the electric blower 100 on and off.

[0069] When the switch unit 305 is operated, the electric blower 100 housed in the vacuum cleaner body 301 starts operating, and an intake airflow is generated at the suction port 307. The intake airflow draws dust from the floor surface through the suction port 307. The sucked-in dust is collected in the dust collection unit 302 of the vacuum cleaner body 301 through the extension pipe 306.

[0070] Furthermore, this method is not limited to the stick-type vacuum cleaner shown in the illustration; it can also be applied to handheld vacuum cleaners, canister vacuum cleaners (cylinder-type vacuum cleaners), and other types of vacuum cleaners. It can also be applied to corded vacuum cleaners with a similar configuration.

[0071] According to this embodiment, since the electric blower 100 of any of Examples 1 to 4 is included, it is possible to provide a vacuum cleaner that is small, lightweight, and has suppressed performance degradation.

[0072] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are included. For example, the embodiments described above are described in detail to make the present invention easier to understand, and are not necessarily limited to those having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add configurations from other embodiments to the configuration of one embodiment. In addition, it is possible to add, delete, or replace parts of the configuration of each embodiment with other configurations. [Explanation of Symbols]

[0073] 1...Fan casing, 2...Matching part, 3...Housing, 4...Bearing cap, 10...Impeller, 14...Impeller outlet, 20...Upstream housing, 21...Upstream inner wall, 22...Upstream outer wall, 23...First axial diffuser blade, 23a...Leading edge, 24...Mounting part, 25...Claw projection, 26...Claw projection, 27...Fixing hole, 29...Vaneless diffuser flow path, 30...Downstream housing, 31...Downstream outer wall, 32...Second axial diffuser blade, 33...Downstream projection, 34...Matching hole, 41...Outer wall, 50...Rotor assembly, 51...Rotating shaft, 52...Upstream bearing, 53...Downstream bearing, 54...Bearing holder, 55...Rotor core, 56...Balance ring, 60 ...stator, 61...stator core, 62...insulator, 62a...upstream insulator, 62b...downstream insulator, 63...coil, 64...terminal, 65...terminal holder, 66...protrusion, 66a...gap, 67...notch, 70...frame, 73...exhaust opening, 75...large diameter section, 80...bolt, 81...teeth, 82...slot, 83...air gap, 86...yoke, 90...air intake, 91...exhaust port, 100...electric blower, 200...motor, 300...electric vacuum cleaner, 301...vacuum cleaner body, 302...dust collection section, 303...battery unit, 304...grip section, 305...switch section, 306...extension tube, 307...suction nozzle

Claims

1. An electric blower comprising a rotor, a rotating shaft provided on the rotor, an impeller fixed to the rotating shaft, a stator disposed on the outer circumferential surface of the rotor via an air gap and equipped with a coil, and a housing disposed downstream of the impeller and equipped with diffuser blades, wherein the stator is provided with a stator core having a plurality of teeth around which the coil is wound, The housing and the stator are provided with bolts for fixing them in the axial direction, The bolt is positioned radially outward of the coil and radially inward of the inner wall of the housing, which has the diffuser blades radially outward. The electric blower is characterized in that the stator core is provided with an insertion portion that extends in the axial direction and through which the bolt passes.

2. An electric blower according to claim 1, The aforementioned insertion portion is a notch in the stator core that is open in the radial direction, characterized in that of the electric blower.

3. The electric blower according to claim 2, The aforementioned notches are arranged to be inclined at a predetermined angle in the circumferential direction with respect to the radial direction. An electric blower characterized in that the inclination direction of the notch is the same as the inclination direction of the diffuser blade.

4. An electric blower according to claim 3, An electric blower characterized in that the corners of the notched portion are chamfered.

5. An electric blower according to claim 3, An electric blower characterized in that, when the minimum width of the teeth is W, and the width that minimizes the distance between the bolt and the stator core located radially inward from the bolt is D, the inclination angle of the notch satisfies the relationship D ≥ W / 2.

6. An electric blower according to any one of claims 1 to 5, An electric blower characterized in that the bolt is positioned radially outward of the teeth.

7. An electric vacuum cleaner comprising: a vacuum cleaner body equipped with an electric blower and a dust collection unit for collecting dust collected by the suction force generated by the electric blower; an extension pipe with one end connected to the vacuum cleaner body and communicating with the dust collection unit; and a suction nozzle connected to the other end of the extension pipe, The electric blower is characterized in that it is the electric blower described in any one of claims 1 to 5.

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