Electric blowers and vacuum cleaners

Abstract

The present invention provides an electric blower that can improve the cooling performance of heat-generating parts and achieve this cooling performance with low pressure loss. [Solution] The electric blower according to the present invention comprises a rotor 50 having a rotating shaft 51, an impeller 10 fixed to one end of the rotating shaft 51, and a rotor core 55 fixed to the rotating shaft 51; a stator 60 having a stator core 61 located on the outer circumference side of the rotor core 55; and a frame 70. The rotor 50 includes a downstream bearing 53 located between the impeller 10 and the rotor core 55 and supporting the rotating shaft 51, and an upstream bearing 52 located between the impeller 10 and the downstream bearing 53 and supporting the rotating shaft 51. The frame 70 has a rising portion 76 that protrudes radially inward and abuts against the downstream bearing 53, and an exhaust hole 73 that penetrates the side radially, and covers from the upstream end 52d of the upstream bearing 52 to the downstream end 61a of the stator core 61 in the axial direction.

Description

Technical Field

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

Background Art

[0002] In recent years, there has been an increasing demand for miniaturization and weight reduction of vacuum cleaners. For miniaturization and weight reduction of vacuum cleaners, increasing the operating rotational speed of the impeller and rotor of an electric blower, i.e., high-speed rotation, is effective. For this reason, an electric blower having a structure corresponding to high-speed rotation using a brushless motor has been proposed.

[0003] An example of a conventional electric blower is described in Patent Document 1. The electric blower described in Patent Document 1 includes a rotor assembly and a housing that houses the rotor assembly and has an air inlet and an air outlet. The rotor assembly includes a shaft, an impeller attached to the shaft, a rotor core attached to the shaft, and a pair of bearings whose inner peripheral side is attached to the outer periphery of the shaft and whose outer peripheral side is fixed to the housing. The pair of bearings is disposed between the impeller and the rotor core. The housing includes a frame integrally formed of a bearing holding portion that holds the outer peripheral surface of the pair of bearings in contact therewith and a stator holding portion that holds a stator that drives the rotor core.

[0004] Since the electric blower described in Patent Document 1 includes a frame in which a bearing holding portion that holds the outer peripheral surface of the bearing in contact therewith and a stator holding portion are integrally formed, heat generated by the bearing can be efficiently dissipated.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In electric vacuum cleaners and similar devices, further increases in the rotational speed of electric blowers are required from the standpoint of miniaturization and weight reduction. In electric blowers, miniaturization and weight reduction reduce the heat dissipation area of ​​the heat-generating parts, and the losses in the bearings and stator core increase due to high-speed rotation. As a result, the internal heat density of electric blowers increases, so it is necessary to improve the cooling performance of the heat-generating parts.

[0007] Furthermore, electric blowers are required to be smaller, lighter, and more efficient, and it is necessary to cool the heat-generating parts, where the heat density increases, with low pressure loss.

[0008] The object of the present invention is to provide an electric blower that can improve the cooling performance of heat-generating parts and achieve this cooling performance with low pressure loss, and an electric vacuum cleaner equipped with this electric blower. [Means for solving the problem]

[0009] The electric blower according to the present invention comprises a rotor having a rotating shaft, an impeller fixed to one end of the rotating shaft, and a rotor core fixed to the rotating shaft, a stator having a stator core located on the outer circumference side of the rotor core, and a frame. The direction of extension of the rotating shaft is defined as the axial direction, and the radial direction as the radial direction. The upstream side and the downstream side represent the direction of the airflow generated by the rotation of the impeller. The rotor comprises a downstream bearing located between the impeller and the rotor core and supporting the rotating shaft, and an upstream bearing located between the impeller and the downstream bearing and supporting the rotating shaft. The frame comprises a rising portion that protrudes inward in the radial direction and abuts against the downstream bearing, and an exhaust hole that penetrates the side surface in the radial direction, and covers from the upstream end of the upstream bearing to the downstream end of the stator core in the axial direction.

[0010] The vacuum cleaner according to the present invention is equipped with an electric blower according to the present invention. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide an electric blower that can improve the cooling performance of a heat-generating part and can achieve this cooling performance with low pressure loss, and a vacuum cleaner including this electric blower.

Brief Description of the Drawings

[0012] [Figure 1A] External view of the electric blower according to an embodiment of the present invention. [Figure 1B] Longitudinal sectional view of the electric blower according to this embodiment. [Figure 2] Exploded perspective view of the electric blower according to this embodiment. [Figure 3A] Perspective view of the impeller. [Figure 3B] Longitudinal sectional view of the impeller. [Figure 4A] Front view of the upstream housing as seen from the upstream side. [Figure 4B] Longitudinal sectional view of the upstream housing. [Figure 4C] View showing the upstream housing excluding a part of its outer peripheral portion. [Figure 5A] Front view of the downstream housing as seen from the upstream side. [Figure 5B] Longitudinal sectional view of the downstream housing. [Figure 6A] External view of the rotor. [Figure 6B] Longitudinal sectional view of the rotor. [Figure 7] External view of the stator. [Figure 8A] Perspective view showing the appearance of the frame. [Figure 8B] Longitudinal sectional view of the frame. [Figure 8C] View showing the rising part of the frame, which is an enlarged view of the part shown in circle A in FIG. 8B. [Figure 9A] External view of the rotating body support assembly included in the electric blower according to this embodiment. [Figure 9B] Longitudinal sectional view of the rotating body support assembly. [Figure 9C] View showing a cross section perpendicular to the axial direction of the stator core of the stator and the frame, which is the X-X cross-sectional view in FIG. 9A. [Figure 10] Perspective view showing the appearance of the vacuum cleaner according to this embodiment.

Embodiment for Carrying out the Invention

[0013] The electric blower according to the present invention includes a rotor having a rotating shaft and a pair of bearings (an upstream bearing and a downstream bearing), a stator located on the outer peripheral side of the rotor core, and a frame that covers from the upstream end portion of the upstream bearing to the downstream end portion of the stator core. It can improve the cooling performance of the heat-generating part, and can realize this cooling performance with low pressure loss. According to the present invention, it is possible to provide a small and lightweight electric blower with suppressed heat generation amount, and a vacuum cleaner provided with this electric blower.

[0014] Hereinafter, the electric blower and the vacuum cleaner according to the embodiments of the present invention will be described in detail with reference to the drawings. Hereinafter, the extending direction of the rotating shaft of the rotor included in the electric blower is called the axial direction, the rotating direction of the rotating shaft is called the circumferential direction, and the radial direction of the rotating shaft is called the radial direction. Also, in the axial direction, the upstream side of the air flow inside the electric blower is called up (upper side, upward direction), and the downstream side is called down (lower side, downward direction). The upstream side and the downstream side represent the directions regarding the axial flow of air generated by the rotation of the impeller included in the electric blower. The upstream side and the downstream side of the air flow may also be simply called the upstream and the downstream, respectively.

[0015] In the drawings referred to in this specification, the same or corresponding components are denoted by the same reference numerals, and repeated descriptions of these components may be omitted.

Embodiment

[0016] <Electric Blower> FIG. 1A is an external view of an electric blower 100 according to an embodiment of the present invention. FIG. 1B is a longitudinal sectional view of the electric blower 100 according to this embodiment. FIG. 2 is an exploded perspective view of the electric blower 凭0 according to this embodiment.

[0017] As shown in Figures 1A, 1B, and 2, the electric blower 100 comprises a fan casing 1 covering the impeller 10, a bearing cap 4, an upstream housing 20, a downstream housing 30, a rotor 50, a stator 60, and a frame 70. The upstream housing 20 and the downstream housing 30 constitute a housing 3. The frame 70 covers the axial direction from the upper end 52d (upstream end) of the upstream bearing 52 of the rotor 50 to the lower end 61a (downstream end) of the stator core 61 of the stator 60. The frame 70 covers the outer circumference of the upstream bearing 52 and the stator core 61.

[0018] The fan casing 1 is made of resin or the like and has a hollow conical shape. The fan casing 1 has openings at its upper and lower axial ends and accommodates part or all of the impeller 10. The opening at the upper end of the fan casing 1 is the air intake port 90.

[0019] The fan casing 1 is attached to the upstream housing 20 by being placed over the impeller 10 from the axial upper side. The fan casing 1 is positioned when its fitting portion 2 engages with a protrusion 25 on the upstream housing 20. By injecting adhesive or the like into the fitting portion 2, the fan casing 1 is fixed to the upstream housing 20 and leakage of fluid (cooling air) from the fitting portion 2 is prevented.

[0020] Figure 4A is a front view of the upstream housing 20 as seen from the upstream side. Figure 4B is a longitudinal cross-sectional view of the upstream housing 20. Figure 4C is a view of the upstream housing 20 with a portion of its outer periphery removed.

[0021] As shown in Figures 4A, 4B, and 4C, the upstream housing 20 comprises a disc-shaped mounting portion 24 including a plane perpendicular to the axial direction, an upstream inner wall 21, an upstream outer wall 22, and a first axial flow diffuser blade 23. The upstream inner wall 21 extends from the outer circumference of the mounting portion 24 downward in the axial direction, inclined with respect to the axial direction. The upstream outer wall 22 is provided radially outside the upstream inner wall 21, with a gap between it and the upstream inner wall 21. The first axial flow diffuser blade 23 is located downstream of the impeller 10 and is installed in the gap between the upstream inner wall 21 and the upstream outer wall 22, connecting the upstream inner wall 21 and the upstream outer wall 22 while decelerating the fluid (cooling air) and increasing the fluid pressure.

[0022] Figure 5A is a front view of the downstream housing 30 as seen from the upstream side. Figure 5B is a longitudinal cross-sectional view of the downstream housing 30.

[0023] As shown in Figures 5A and 5B, the downstream housing 30 includes a downstream outer wall 31 provided on its outer circumference and a second axial flow diffuser blade 32 that decelerates the fluid (cooling air) and increases the fluid pressure. The second axial flow diffuser blade 32 is located downstream of the first axial flow diffuser blade 23 and is installed radially inward from the downstream outer wall 31.

[0024] The upstream housing 20 and the downstream housing 30 are fixed to each other by fitting the claw projection 26 (Figure 4C) of the upstream housing 20 into a fitting hole 34 provided in the downstream projection 33 (Figure 5B) of the downstream housing 30 (Figure 1A). The upstream housing 20 and the downstream housing 30 constitute the housing 3 in this way. However, in addition to fitting the claw projection 26 and the fitting hole 34, the upstream housing 20 and the downstream housing 30 may also be fixed to each other using adhesive or other means.

[0025] As a result, the upstream outer wall 22 of the upstream housing 20 and the downstream outer wall 31 of the downstream housing 30 become one with each other, forming a substantially cylindrical, thick outer wall 41 (Figure 1B) that extends in the axial direction. The outer wall 41 faces the exhaust holes 73 (see Figures 8A and 8B described later) of the frame 70 radially, with a gap in between. The materials used for the upstream housing 20 and the downstream housing 30 can be resin, aluminum alloy, etc. In this embodiment, the housing 3 is divided into the upstream housing 20 and the downstream housing 30, but it may not be divided into multiple parts and may be constructed as a single unit from the beginning.

[0026] The bearing cap 4 (Figures 1B and 2) is held in the upstream housing 20 and fixed by adhesive or the like. As shown in Figure 1B, the bearing cap 4, together with the upstream inner wall 21 (Figure 4B) of the upstream housing 20 and the fan casing 1, forms a vaneless diffuser 28, which is a flow path, in order to guide the airflow from the impeller 10 to the first axial diffuser blades 23. The bearing cap 4 is also fitted into the upstream housing fitting hole 27 (Figure 4) of the upstream housing 20 so as to abut against the frame 70, and prevents the rotor 50 from coming off due to the negative pressure of the impeller 10. The bearing cap 4 may be composed of, for example, a plurality of semicircular parts connected in the circumferential direction.

[0027] The rotor 50 (Figure 2) is inserted from the upper axial side into the bearing housing 71 (see Figure 2 and Figures 8A and 8B described later) of the frame 70, and is fixed by adhesive or the like so as to abut against the rising portion 76 of the frame 70 (see Figure 1B and Figures 8B and 8C described later).

[0028] The stator 60 is inserted from the axial lower side to the end of the stator housing 72 (see Figures 8A and 8B described later) provided in the frame 70, and is fixed using, for example, a grub screw. At this time, the frame 70 is inserted into the upstream housing 20 and positioned. In this embodiment, the upstream housing 20 and the stator 60 are fixed to each other by screws, but they may be fixed by other methods such as adhesive, press-fit, and welding.

[0029] Figure 6A is an external view of the rotor 50.

[0030] The rotor 50 comprises an impeller 10, a rotating shaft 51, an upstream bearing 52, a spring 54, a downstream bearing 53, a rotor core 55, and a balance ring 56. The impeller 10, upstream bearing 52, spring 54, downstream bearing 53, rotor core 55, and balance ring 56 are mounted on the rotating shaft 51 in this order from upstream to downstream. The upstream bearing 52 and the downstream bearing 53 support the rotating shaft 51. Figure 6A also shows the axial upper end 52d of the upstream bearing 52.

[0031] The rotor 50 is circumferentially rotatable as the rotation shaft 51 rotates. When the rotor 50 rotates, the impeller 10 rotates, creating an airflow inside the electric blower 100. This air flows axially from the impeller 10 towards the rotor core 55.

[0032] Because the rotor 50 rotates at high speeds, such as 200,000 revolutions per minute, poor balance of the rotating body can affect vibrations during operation of the electric blower 100 and damage to the bearings. Therefore, by machining the impeller 10 and balance ring 56 during the manufacturing of the rotor 50, the rotational balance of the rotor 50 can be adjusted, and the rotor 50 can be assembled to the frame 70 in a well-balanced state during rotation.

[0033] Figure 3A is a perspective view of the impeller 10. Figure 3B is a longitudinal cross-sectional view of the impeller 10.

[0034] The impeller 10 has a press-fit portion 13 on its upstream side. The press-fit portion 13 of the impeller 10 is fixed to one end of the rotor 50's rotating shaft 51 by press-fitting (Figure 6A). The impeller 10 comprises a hub plate 11 and a plurality of blades 12. The hub plate 11 and the blades 12 are made of aluminum alloy or magnesium alloy and are integrally formed by machining.

[0035] A protrusion 11a (Figure 3B) is provided on the back (downstream) surface of the hub plate 11. By rotating the impeller 10 during the manufacturing of the rotor 50 and grinding down the protrusion 11a, the balance of the rotor 50 during rotation can be adjusted in conjunction with the balance ring 56.

[0036] The impeller 10 is preferably made of a material with high thermal conductivity, such as an aluminum alloy or magnesium alloy, or a high-strength resin mixed with a material that enhances thermal conductivity. An impeller 10 configured in this way can improve the cooling performance of the upstream bearing 52 and the downstream bearing 53.

[0037] The rotating shaft 51 shown in Figure 6A has an elongated cylindrical shape and is made of a magnetic material such as iron. However, the rotating shaft 51 is not limited to such magnetic materials and may be made of a non-magnetic material such as stainless steel (SUS).

[0038] As shown in Figure 6A, the upstream bearing 52 and the downstream bearing 53 are located approximately in the axial center of the rotating shaft 51, spaced apart from each other in the axial direction. The downstream bearing 53 is located between the impeller 10 and the rotor core 55. The upstream bearing 52 is located upstream of the downstream bearing 53, i.e., between the impeller 10 and the downstream bearing 53. A spring 54 is provided between the upstream bearing 52 and the downstream bearing 53.

[0039] Figure 6B is a longitudinal cross-sectional view of the rotor 50. Figure 6B also shows the axial upper end 52d of the upstream bearing 52.

[0040] The upstream bearing 52 comprises, for example, an upstream bearing outer ring 52a, an upstream bearing inner ring 52b, and a plurality of upstream balls 52c. The upstream bearing outer ring 52a is fixed to the bearing housing 71 of the frame 70 (see Figures 8A and 8B described later). The upstream bearing inner ring 52b is fixed to the rotating shaft 51.

[0041] The downstream bearing 53 comprises, for example, a downstream bearing outer ring 53a, a downstream bearing inner ring 53b, and a plurality of downstream balls 53c. The downstream bearing outer ring 53a is fixed to the bearing housing 71 of the frame 70. The downstream bearing inner ring 53b is fixed to the rotating shaft 51.

[0042] The spring 54 is a coil spring and biases the outer ring 52a of the upstream bearing 52 and the outer ring 53a of the downstream bearing 53 in a direction that moves them apart from each other. By preventing rattling between the upstream bearing 52 and the downstream bearing 53, the spring 54 suppresses noise and vibration of the electric blower 100.

[0043] The rotor core 55 (Figures 6A and 6B) is made up of permanent magnets and is fixed to the side of the rotating shaft 51. A balance ring 56 is also fixed around the rotating shaft 51 on the axial downstream side of the rotor core 55.

[0044] The balance ring 56 can be made of a non-magnetic metal material such as brass. The balance ring 56 has the same diameter as the rotor core 55 and is fixed to the rotating shaft 51 so as to be in contact with the downstream end face of the rotor core 55. The balance ring 56 is formed by machining or other processes and, as mentioned above, has the function of adjusting the balance of the rotor 50 during rotation together with the impeller 10.

[0045] Figure 7 is an external view of the stator 60.

[0046] The stator 60 comprises a stator core 61, an upstream insulator 62, a downstream insulator 63, a coil 64, and terminals 65. The coil 64 is wound around the upstream insulator 62 and the downstream insulator 63. Figure 7 also shows the lower end portion 61a of the stator core 61. The rotor 50 is located inside the stator 60.

[0047] The rotor core 55 (Figures 6A and 6B) is positioned on the inner circumference side of the stator core 61, separated by an air gap. In other words, the stator core 61 is located on the outer circumference side of the rotor core 55, and the inner surface of the stator core 61 faces the outer surface of the rotor core 55. The stator core 61 is made of electrical steel sheet with iron as the main component.

[0048] The upstream insulator 62 and the downstream insulator 63 are made of resin such as PET (polyethylene terephthalate). The coil 64 is made of copper or aluminum alloy.

[0049] In the electric blower 100 according to this embodiment, the upstream bearing 52 and downstream bearing 53 of the rotor 50 (Figure 6A), and the stator core 61 and coil 64 of the stator 60 (Figure 7) are the heat-generating parts.

[0050] The stator 60 and the rotor 50 located inside the stator 60 are covered in the axial direction by the frame 70 from the upper end 52d of the upstream bearing 52 of the rotor 50 to the lower end 61a of the stator core 61.

[0051] The frame 70 covers the area from the upper end 52d of the upstream bearing 52 to the lower end 61a of the stator core 61 in the axial direction, and covers the outer circumference of the upstream bearing 52 and the stator core 61 in the circumferential direction.

[0052] Figure 8A is a perspective view showing the external appearance of frame 70. Figure 8B is a longitudinal cross-sectional view (cross-sectional view seen from the side) of frame 70. Figure 8C shows the rising portion 76 of frame 70, and is an enlarged view of the portion indicated by circle A in Figure 8B.

[0053] The frame 70 comprises a cylindrical bearing housing 71 with an open upstream side and a cylindrical stator housing 72 with an open downstream side. The downstream opening of the stator housing 72 is the opening 77 of the frame 70. The frame 70 is made of an aluminum alloy or a magnesium alloy.

[0054] The bearing housing 71 is provided with upstream housing fitting ribs 75 on its sides, which are fitted with the upstream housing 20.

[0055] The stator housing 72 is located downstream of the bearing housing 71 and is radially larger than the bearing housing 71. The upstream surface (top surface) of the stator housing 72 is in contact with the bearing housing 71. The stator housing 72 is provided with a plurality of exhaust holes 73 on its side.

[0056] Multiple exhaust holes 73 are through-holes that penetrate radially through the side of the frame 70 and are arranged circumferentially on the upper part of the side of the stator housing 72. The exhaust holes 73 are located upstream of the stator core 61 (towards the impeller 10). In addition, set screw holes 74 are provided on the side of the stator housing 72 through which set screws that fix the stator housing 72 to the stator 60 pass.

[0057] The rising portion 76 (Figures 8B and 8C) is the part of the upper surface (upstream side) of the stator housing 72 that protrudes radially inward from the inner circumferential surface of the bearing housing 71. The rising portion 76 is in contact with the downstream bearing 53 of the rotor 50.

[0058] Since the multiple exhaust ports 73 are provided on the side of the stator housing 72, they are located downstream of the rising section 76.

[0059] The following describes the characteristic configuration of the electric blower 100 according to this embodiment.

[0060] Figure 9A is an external view of the rotating body support assembly 200 provided in the electric blower 100 according to this embodiment. Figure 9B is a longitudinal cross-sectional view (cross-sectional view seen from the side) of the rotating body support assembly 200.

[0061] The rotating body support assembly 200 comprises a frame 70, a rotor 50, and a stator 60.

[0062] The frame 70 is made of an aluminum alloy or a magnesium alloy. Aluminum and magnesium alloys are lighter and have higher thermal conductivity than stainless steel. In the axial direction, the frame 70 covers from the upper end 52d of the upstream bearing 52 of the rotor 50 to the lower end 61a of the stator core 61 of the stator 60, and is in contact with the outer ring 52a of the upstream bearing, the outer ring 53a of the downstream bearing, and the stator core 61. As a result, the frame 70 increases the heat dissipation area of ​​the heat-generating parts, namely the upstream bearing 52, the downstream bearing 53, and the stator core 61, thereby improving the cooling performance of the heat-generating parts.

[0063] Furthermore, the stator housing portion 72 of the frame 70 abuts the stator core 61 on its inner circumferential surface and abuts the second axial-flow diffuser blade 32 (Figure 5B) of the downstream housing 30 on its outer circumferential surface (Figure 1B). As a result, the frame 70 can improve the cooling performance of heat-generating parts by cooling air, as will be described later. Cooling air flows into the opening 77 of the frame 70, as will be described later.

[0064] The rotor 50 is inserted into the bearing housing 71 of the frame 70 from the upstream side and assembled to the frame 70. In the axial direction, the frame 70 covers the rotor 50 from the upper end 52d of the upstream bearing 52 to the lower end of the downstream bearing 53. The frame 70 houses the upstream bearing 52, the spring 54, and the downstream bearing 53, and supports the downstream bearing 53 at the rising portion 76 to determine the position of the downstream bearing 53.

[0065] The stator 60 is housed in the stator housing 72 so as to surround the rotor core 55 of the rotor 50. The frame 70 covers the stator 60 in the axial direction from the upper end of the stator 60 to the lower end 61a of the stator core 61.

[0066] Figure 9C is a diagram showing a cross-section of the stator core 61 and frame 70 of the stator 60 perpendicular to the axial direction, and is the XX cross-section of Figure 9A.

[0067] The stator core 61 has an annular outer surface and includes a recess 84, teeth 81 around which the coils 64 are wound, slots 82, and an air gap 83. The recess 84 is provided on the outer surface of the stator core 61 and is recessed radially inward. The slots 82 are flow paths formed by adjacent coils 64. The air gap 83 is the gap between the rotor core 55 and the stator core 61.

[0068] The frame 70 covers the stator core 61 in the axial and circumferential directions and is in close contact with the stator core 61 without any gaps, except for the portion of the recess 84. The portion of the stator core 61 surrounded by the frame 70 and the recess 84 is the recessed flow path 85.

[0069] The rotating body support assembly 200 is equipped with a recessed flow channel 85, which generates airflow. This airflow improves the cooling performance of the outer circumference of the stator 60 and the cooling performance of the frame 70.

[0070] <Airflow inside the electric blower 100> Next, the airflow inside the electric blower 100 will be explained with reference to Figure 1B. When the rotor 50 rotates and the impeller 10 rotates, a main flow is generated inside the electric blower 100, flowing from the upstream side to the downstream side.

[0071] Figure 1B shows the main flow F1 flowing from upstream to downstream with a dashed arrow. The main flow F1 is the air that flows into the electric blower 100 from the air intake 90 of the fan casing 1 and flows into the impeller 10. If the impeller 10 is a mixed-flow type impeller, the impeller 10 pressurizes the incoming air with its blades 12, adding a radial flow component to the axial flow, and generating an inclined flow with both axial and radial components. In this way, at the impeller outlet 14, the main flow F1 becomes a flow in which the circumferential (rotational direction) component and the axial component are combined and flow out of the impeller 10.

[0072] The main flow F1 flowing out from the impeller 10 gradually changes direction within the vaneless diffuser 28 to a radial position identical to the outermost diameter portion of the stator core 61 or the outermost diameter portion 78 of the frame 70, and the flow is slowed down by a gradual increase in the flow path cross-sectional area within the vaneless diffuser 28. Subsequently, the main flow F1 passes through the first axial diffuser blades 23 and the second axial diffuser blades 32, where the circumferential component (rotational component) is converted to an axial component and slowed down, causing the static pressure to increase, and it is exhausted from the exhaust port 91. The exhaust port 91 is the downstream opening of the downstream housing 30.

[0073] The main flow F1 has a high velocity and lower pressure at the outlet of the first axial diffuser blade 23 than at the exhaust port 91. The opening 77 of the frame 70 is located close to the outlet of the first axial diffuser blade 23 and therefore has the same effect on the air as the outlet of the first axial diffuser blade 23. As a result, due to the Venturi effect, a cooling flow F2 is generated that enters the opening 77 of the frame 70 from the exhaust port 91, passes through the inside of the electric blower 100, and heads toward the exhaust port 73 of the frame 70 (Figures 8A and 8B). In Figure 1B, the cooling flow F2 is shown by a dashed arrow.

[0074] Since the bearing housing 71 of the impeller 10 and frame 70 is made of aluminum alloy or magnesium alloy, which have high thermal conductivity, the upstream bearing 52 and downstream bearing 53 are cooled by heat transfer when the main flow F1 flows along the outer wall (outermost diameter part 78) of the frame 70. In addition, the upstream bearing 52, which is closer to the impeller 10 in the axial direction, is also cooled by the cooling of the rotating impeller 10, which in turn cools the part of the rotating shaft 51 closest to the impeller 10 through heat conduction.

[0075] Next, let's explain the cooling flow F2. The cooling flow F2 is the flow of fluid (cooling air) that cools the rotating body support assembly 200 (frame 70, rotor 50, and stator 60).

[0076] The cooling flow F2 is drawn in through the opening 77 of the frame 70 and flows through the stator core 61 and coil 64, etc., towards the exhaust port 73 of the frame 70 (Figures 8A and 8B). The cooling flow F2 is then exhausted from the exhaust port 73 between the frame 70 and the upstream outer wall 22 of the upstream housing 20. In the frame 70, the bearing housing 71 is in communication with the stator housing 72, but the cooling flow F2 that flows into the stator housing 72 is exhausted from the exhaust port 73 and does not flow into the bearing housing 71. The cooling flow F2 exhausted from the exhaust port 73 flows outside the stator housing 72, which is made of aluminum alloy or magnesium alloy, and cools the stator housing 72.

[0077] The cooling flow F2 exhausted from the exhaust port 73 between the frame 70 and the upstream outer wall 22 of the upstream housing 20 flows toward the exhaust port 91, merges with the main flow F1 either upstream of the second axial diffuser blade 32 or within the inter-blade flow path of the second axial diffuser blade 32, and is exhausted at the exhaust port 91.

[0078] The airflow rate through the second axial diffuser blade 32 is increased by the amount of the cooling flow F2 compared to the airflow rate of the main flow F1 through the first axial diffuser blade 23. This increase in airflow rate reduces airflow separation at the second axial diffuser blade 32, enabling higher efficiency of the electric blower 100.

[0079] As the cooling flow F2 moves from the opening 77 of the frame 70 towards the exhaust port 73 of the frame 70, it branches into a flow that passes through the recessed passage 85 of the stator core 61 (Figure 9C), the air gap 83, and the slot 82. After cooling the stator core 61, the coil 64, and the permanent magnets of the rotor 50, it collides with the rising portion 76 of the frame 70 and the downstream bearing 53, where it is further cooled. After cooling, the cooling flow F2 merges with the main flow F1 and exchanges heat with the main flow F1. The combined flow of the main flow F1 and the cooling flow F2 is then exhausted to the outside, cooling the electric blower 100.

[0080] The electric blower 100 according to this embodiment does not have a deflector or guide to change the direction of the airflow in order to draw cooling air into the electric blower 100, and cools the inside of the electric blower 100 by drawing in air (cooling flow F2) through the Venturi effect. Therefore, the electric blower 100 according to this embodiment can achieve cooling of heat-generating parts with low pressure loss and can also be made highly efficient. Furthermore, since the electric blower 100 according to this embodiment does not have a deflector or guide for the cooling air, it can maintain high airflow efficiency even at non-design points and can achieve high efficiency over a wide operating range.

[0081] Next, the effects of the electric blower 100 according to this embodiment will be described. In the electric blower 100, as shown in Figure 9C, the stator 60 has a recessed flow path 85 in addition to the slot 82 and air gap 83. The recessed flow path 85 is open in the axial direction, and a cooling flow F2 flows through it. That is, in the electric blower 100, the flow area of ​​the cooling flow F2 can be increased by the recessed flow path 85, so that the flow resistance can be reduced and the flow rate of the cooling air can be increased. As a result, the electric blower 100 according to this embodiment can promote the cooling of the rotating body support assembly 200 (frame 70, rotor 50, and stator 60).

[0082] The inner wall of the stator housing 72 of the frame 70 (Figure 8B) covers the stator core 61 in the axial and circumferential directions, and is configured to be in close contact with the stator core 61 without any gaps except for the portion of the recess 84 (Figure 9C). The frame 70 also has an exhaust hole 73 that penetrates radially at a position upstream of the stator core 61 (towards the impeller 10). With this configuration, the electric blower 100 guides the cooling flow F2 toward the side of the stator core 61 closer to the impeller 10 without the cooling flow leaking radially outward along the recess flow path 85.

[0083] The side of the rotating body support assembly 200 (frame 70, rotor 50, and stator 60) closest to the impeller 10 is located downstream of the cooling flow F2. Compared to the opening 77 of the frame 70 into which the cooling flow F2 is drawn, the fluid temperature is higher due to heat transfer from the stator core 61, downstream bearing 53, and coil 64, raising concerns about temperature rise. However, in the electric blower 100, the cooled air (cooling flow F2) after cooling collides with the rising portion 76 of the frame 70 and is cooled, thus efficiently reducing the temperature on the side of the rotating body support assembly 200 closest to the impeller 10.

[0084] The frame 70 is constructed as a separate component from the upstream housing 20 and the downstream housing 30. This allows the frame 70 to have exhaust holes 73 at any position and of any area, without excessively impairing the rigidity of the rotating body support assembly 200 or the holding force between the stator core 61 and the mounting portion 24 (Figure 4B) of the upstream housing 20. As a result, the electric blower 100 can reduce pressure loss due to the flow of cooling air, increase the amount of cooling air, and improve the cooling performance of the rotating body support assembly 200.

[0085] The frame 70 is made of a metal alloy (aluminum alloy or magnesium alloy) with high thermal conductivity and high rigidity. As a result, the electric blower 100 promotes heat transfer from the upstream bearing 52, the downstream bearing 53 and the stator core 61 to the cooling flow F2, reducing the temperature of the rotating body support assembly 200 and increasing the rigidity of the rotating body support assembly 200, thereby suppressing vibration and noise during operation.

[0086] <Vacuum Cleaner Configuration> The following describes the vacuum cleaner according to this embodiment. The electric blower 100 according to this embodiment described above can be used, for example, as the fan motor of the vacuum cleaner according to this embodiment.

[0087] Figure 10 is a perspective view showing the external appearance of the vacuum cleaner 300 according to this embodiment. The vacuum cleaner 300 according to this embodiment includes the electric blower 100 according to this embodiment. Figure 10 shows a stick-type vacuum cleaner as an example.

[0088] The vacuum cleaner 300 according to this embodiment includes a dust collection chamber 302 for collecting dust, a vacuum cleaner body 301, an extension tube 306, and a suction nozzle 307.

[0089] The vacuum cleaner body 301 houses an electric blower 100 that generates the suction airflow necessary for dust collection. The vacuum cleaner body 301 also includes a battery unit 303, which is the power source, a grip section 304, and a switch section 305 located on the grip section 304. The switch section 305 is used to turn the electric blower 100 on and off.

[0090] When the switch unit 305 is operated and the power to the electric blower 100 is turned on, the electric blower 100 starts operating, and an intake airflow is generated at the suction port 307. This intake airflow draws dust from the floor surface through the suction port 307. The sucked-in dust is collected in the dust collection chamber 302 of the vacuum cleaner body 301 via the extension pipe 306.

[0091] Furthermore, the vacuum cleaner 300 according to this embodiment is not limited to the stick-type vacuum cleaner shown in Figure 10, but can be applied to any vacuum cleaner, such as a handheld vacuum cleaner or a canister vacuum cleaner (cylinder-type vacuum cleaner). Also, the vacuum cleaner 300 according to this embodiment is not limited to a cordless vacuum cleaner equipped with a battery unit 303, but may be a corded vacuum cleaner.

[0092] It should be noted that the present invention is not limited to the embodiments described above, and various modifications are possible. For example, the embodiments described above are explained in detail to make the present invention easier to understand, and the present invention is not necessarily limited to embodiments having all the configurations described. Furthermore, it is possible to replace parts of the configuration of one embodiment with the configuration of another embodiment. It is also possible to add configurations from other embodiments to the configuration of one embodiment. Furthermore, it is possible to delete parts of the configuration of each embodiment, or to add or replace other configurations. [Explanation of symbols]

[0093] 1...Fan casing, 2...Matching part, 3...Housing, 4...Bearing cap, 10...Impeller, 11...Hub plate, 11a...Protrusion, 12...Blade, 13...Press-fit part, 14...Impeller outlet, 20...Upstream housing, 21...Upstream inner wall, 22...Upstream outer wall, 23...First axial diffuser blade, 24...Mounting part, 25...Protrusion, 26...Claw projection, 27...Upstream housing fitting hole, 28...Vaneless diffuser The, 30...downstream housing, 31...downstream outer wall, 32...second axial diffuser blade, 33...downstream projection, 34...fitting hole, 41...outer wall, 50...rotor, 51...rotating shaft, 52...upstream bearing, 52a...upstream bearing outer ring, 52b...upstream bearing inner ring, 52c...upstream ball, 52d...upstream bearing upper end, 53...downstream bearing, 53a...downstream bearing outer ring, 53b...downstream bearing inner ring, 53c...downstream ball, 54...spring, 55...rotor core, 56...balance ring, 60...stator, 61...stator core, 61a...lower end of stator core, 62...upstream insulator, 63...downstream insulator, 64...coil, 65...terminal, 70...frame, 71...bearing housing, 72...stator housing, 73...exhaust port, 74...grub screw hole, 75...upstream housing fitting rib, 76...rising section, 77...frame Frame opening, 78... outermost diameter part of the frame, 81... teeth, 82... slot, 83... air gap, 84... recess, 85... recessed flow path, 90... air intake, 91... exhaust port, 100... electric blower, 200... rotating body support assembly, 300... electric vacuum cleaner, 301... vacuum cleaner body, 302... dust collection chamber, 303... battery unit, 304... grip part, 305... switch part, 306... extension tube, 307... suction nozzle.

Claims

1. A rotor comprising a rotating shaft, an impeller fixed to one end of the rotating shaft, and a rotor core fixed to the rotating shaft, A stator comprising a stator core located on the outer circumference side of the rotor core, Frame and, Equipped with, The direction of extension of the aforementioned rotating shaft is defined as the axial direction, and the radial direction is defined as the radial direction. The upstream and downstream sides indicate the direction of the airflow generated by the rotation of the impeller. The rotor comprises a downstream bearing located between the impeller and the rotor core and supporting the rotating shaft, and an upstream bearing located between the impeller and the downstream bearing and supporting the rotating shaft. The aforementioned frame is The rising portion that protrudes radially inward and abuts against the downstream bearing, The side surface has an exhaust port that penetrates in the radial direction, Equipped with, In the axial direction, covering from the upstream end of the upstream bearing to the downstream end of the stator core, An electric blower characterized by the following features.

2. A first axial diffuser blade located downstream of the impeller, A second axial-flow diffuser blade located downstream of the first axial-flow diffuser blade, Equipped with, The frame is in contact with the second axial diffuser wing. The electric blower according to claim 1.

3. The aforementioned frame is A cylindrical bearing housing, A stator housing is cylindrical, located downstream of the bearing housing, and has a larger radial size than the bearing housing, Equipped with, The electric blower according to claim 1.

4. The rising portion is the part of the upstream surface of the stator housing that protrudes radially inward from the inner circumferential surface of the bearing housing. The electric blower according to claim 3.

5. The exhaust port is located downstream of the rising portion in the axial direction. The electric blower according to claim 1.

6. The aforementioned frame is made of aluminum alloy. The electric blower according to claim 1.

7. A vacuum cleaner characterized by comprising an electric blower as described in any one of claims 1 to 6.

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