Electric air blower and vacuum cleaner comprising the same

Abstract

To provide an electric air blower in which a bearing life can be improved by a compact and lightweight support structure.SOLUTION: A frame 70 comprised in an electric air blower according to the present invention comprises: a bearing housing part 71 housing a pair of bearings; a stator housing part 72 having a larger diameter than that of the bearing housing part 71, and housing a portion of the bearing housing part 71 and a stator 60; and a disk part 75 connecting an impeller side end part of the stator housing part 72 and an intermediate portion in the axial direction of the bearing housing part 71. An insulator 62 comprised in a stator core 61 of the stator 60 comprises: a plurality of protruding parts 66 on which a coil 63 is arranged, and containing an anti-impeller side end part of the bearing housing part 71; a gap 66a formed between the adjacent protruding parts 66, and communicating in the axial direction; a guide part 87 continuous with the protruding parts 66. and for guiding the coil 63; and a support part 88 in contact with teeth 81 of the stator core 61. The guide part 87 and the support part 88 are connected via an opening 89.SELECTED DRAWING: Figure 9B

Description

[Technical Field]

[0001] The present invention relates to an electric blower and an electric vacuum cleaner equipped with the same. [Background technology]

[0002] In recent years, there has been an increasing demand for smaller and lighter electric vacuum cleaners. To achieve this, it is effective to increase the operating speed of the impeller or rotor of the electric blower, so a structure that supports high-speed rotation using a brushless motor has been proposed.

[0003] For example, Patent Document 1 discloses an electric blower that is composed of a centrifugal impeller with a shroud plate that forms an intake port, and a fan casing that covers the centrifugal impeller and is arranged so that the intake port end of the shroud plate is closely facing the fan casing, and in which a rib is provided on at least one of the intake port end of the shroud plate or the closely facing fan casing in a direction opposite to the other.

[0004] In Patent Document 1, a rotor assembly has a centrifugal impeller at one end of a rotating shaft, a rotor core at the other end, and a pair of bearings located approximately in the center.The pair of bearings are fixed to a single bearing cover to ensure concentricity of the two bearings, and part of the bearings is enclosed on the inner diameter side of the coil, thereby shortening the distance from the bearings to the center of gravity of the rotor core and reducing the moment load acting on the bearings due to mass imbalance. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2019-31927 Summary of the Invention [Problem to be solved by the invention]

[0006] In electric vacuum cleaners and other appliances, electric blowers are required to rotate at higher speeds in order to make them smaller and lighter.

[0007] When electric blowers are rotated at high speeds, the load caused by mass imbalance increases, and this leads to a reduction in bearing life. To address this issue, a structure that achieves high-precision assembly to suppress the whirling of the rotating shaft and the load is required.

[0008] On the other hand, measures to cope with the increased load and improve precision require an increase in the external dimensions and mass of the support components. For example, increasing the distance between a pair of bearings is known as a way to suppress tilt of the rotating shaft, but this results in an increase in the axial length of the electric blower. In addition, while increasing the rigidity of the support member and rotating shaft is effective in reducing whirling, both require thicker walls and larger diameters, which increases the external dimensions and mass.

[0009] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an electric blower that can improve the bearing life with a small and lightweight support structure, and an electric vacuum cleaner equipped with the same. [Means for solving the problem]

[0010] In order to achieve the above object, the present invention provides: a rotor assembly including a rotor core, a rotary shaft provided in the rotor core, an impeller fixed to the rotary shaft, and a pair of bearings positioned between the impeller and the rotor core and rotatably supporting the rotary shaft; a stator including a stator core, an insulator disposed on the stator core, and a coil wound around the stator core via the insulator, the stator including a portion of the rotor assembly and constituting an electric motor together with the rotor core; a frame covering the rotor assembly and the stator; an upstream housing positioned on the impeller side and radially outward of the frame, the upstream housing including a first axial flow diffuser vane between an upstream inner wall and an upstream outer wall positioned radially outward of the upstream inner wall; a downstream housing positioned on an opposite side of the upstream housing from the impeller and radially outward of the frame, the downstream housing including a second axial flow diffuser vane between the frame and a downstream outer wall positioned radially outward of the frame; a fan casing fixed to the upstream housing, covering the impeller, and having an air inlet through which air flows, The inner radius R of the stator core s , the outer radius R of the bearing b , the outer radius R of the rotor core m is R b >R s >R m Fulfilling the relationship, the frame comprises: a bearing housing section that houses the pair of bearings; a stator housing section that has an opening on the side opposite to the impeller and is larger in diameter than the bearing housing section, and that houses a part of the bearing housing section and the stator; a disk section that connects the impeller side end of the stator housing section to an axial intermediate part of the bearing housing section; and ribs that connect the bearing housing section, the disk section, and the stator housing section, The insulator has a plurality of protruding portions that protrude axially, are arranged in a circumferential direction, and position the coil radially outward, and that contain the end of the bearing storage section opposite the impeller, gaps that are formed between adjacent protruding portions and communicate in the axial direction, guide portions that are connected to the protruding portions and guide the coil, and support portions that abut against the teeth of the stator core, and is characterized in that the guide portions and the support portions are connected via openings. [Effects of the Invention]

[0011] According to the present invention, an electric blower capable of improving the bearing life with a small and lightweight support structure, and an electric vacuum cleaner equipped with the same are provided. [Brief explanation of the drawings]

[0012] [Figure 1A] 1 is an external view of an electric blower 100 according to a first embodiment of the present invention. [Figure 1B]1B is a vertical cross-sectional view of the electric blower 100 shown in FIG. 1A. [Figure 2] FIG. 1 is an exploded perspective view of an electric blower 100 according to a first embodiment of the present invention. [Figure 3A] FIG. 2 is an external perspective view of the impeller 10. [Figure 3B] FIG. 2 is a vertical cross-sectional view of the impeller 10. [Figure 4A] FIG. 2 is a front view of the upstream housing 20 as seen from the upstream side. [Figure 4B] FIG. 2 is a cross-sectional view of the upstream housing 20. [Figure 4C] FIG. 2 is a side view of the upstream housing 20 with a portion cut away. [Figure 5A] FIG. 2 is a front view of the downstream housing 30 as viewed from the upstream side. [Figure 5B] FIG. 2 is a cross-sectional view of the downstream housing 30. [Figure 6A] FIG. 2 is a side view of the rotor assembly 50. [Figure 6B] FIG. 2 is a cross-sectional view of the rotor assembly 50. [Figure 7A] FIG. 2 is a side view of the stator 60. [Figure 7B] FIG. 2 is a perspective view of a stator 60. [Figure 8A] FIG. 2 is a perspective view showing the appearance of a frame 70. [Figure 8B] FIG. 2 is a cross-sectional view of the frame 70 as seen from the side. [Figure 8C] FIG. 2 is a perspective view showing a part of a stator storage section 72 of a frame 70 cut away. [Figure 9A] FIG. 2 is an external view of a rotating body support assembly 200. [Figure 9B] 9B is a cross-sectional view of the rotor support assembly 200 shown in FIG. 9A as viewed from the side. [Figure 9C] FIG. 9C is an enlarged view of part IX in FIG. 9B. [Figure 9D] FIG. 9B is a cross-sectional view taken along line XX in FIG. 9A. [Figure 10A] FIG. 10 is a perspective view of an upstream insulator 62A as viewed from the impeller side. [Figure 10B]FIG. 10 is a perspective view of an upstream insulator 62A as viewed from the side opposite to the impeller. [Figure 11] 10 is a diagram showing the transition of the results of electromagnetic field analysis of eddy current loss in the downstream bearing 53 and the bearing housing portion 71 when the distance Ld between the downstream bearing 53 and the rotor core 55 is changed. FIG. [Figure 12] This figure shows the change in the evaluation function obtained by multiplying the axial length Lax of the rotor assembly 50 by the larger value of the radial load of a pair of bearings (upstream bearing 52, downstream bearing 53) when the bearing span Lc is changed. [Figure 13] 1 is a perspective view showing the appearance of an electric vacuum cleaner 300 according to an embodiment of the present invention. [Figure 14] FIG. 3 is a cross-sectional view of an electric blower 100 according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In principle, identical elements are designated by the same reference numerals in all drawings. Furthermore, descriptions of parts having identical functions will be omitted. Note that the configurations described below are merely examples, and it is not intended that the embodiments of the present invention be limited to the specific embodiments below. [Example]

[0014] <Configuration of electric blower 100> Fig. 1A is an external view of electric blower 100 according to a first embodiment of the present invention. Fig. 1B is a vertical cross-sectional view of electric blower 100 shown in Fig. 1A. Fig. 2 is an exploded perspective view of electric blower 100 according to the first embodiment of the present invention.

[0015] The electric blower 100 comprises an electric motor having a rotor (rotor core 55) and a stator 60 (stator core 61), an impeller 10 fixed to a rotating shaft 51 provided on the rotor (rotor core 55) and driven by the electric motor, an upstream bearing 52 and a downstream bearing 53 located between the impeller 10 and the rotor (rotor core 55) and forming a pair of bearings that rotatably support the rotating shaft 51, a frame 70 that covers from the upstream bearing 52 to the lower end 61a of the stator core of the stator 60, a housing 3 located radially outside the frame 70 and covering part of the frame 70, a fan casing 1 fixed to the housing 3, covering the impeller 10, and having an air intake 90 for air to flow in, and a bearing cap 4 located radially outside the frame 70 that covers the upstream bearing 52. In this embodiment, a rotor assembly 50 is made up of a rotor core 55, a rotating shaft 51, an upstream bearing 52, a downstream bearing 53, an impeller 10, and a spring 54 arranged between the upstream bearing 52 and the downstream bearing 53. A part of the rotor assembly 50 is enclosed within a stator 60 (stator core 61).

[0016] The housing 3 is composed of an upstream housing 20 to which the fan casing 1 is fixed, and a downstream housing 30 fixed to the upstream housing 20. The pair of bearings in this embodiment is composed of an upstream bearing 52 located on the impeller 10 side and a downstream bearing 53 located on the rotor (rotor core 55) side.

[0017] Fig. 3A is an external perspective view of impeller 10. Fig. 3B is a longitudinal cross-sectional view of impeller 10. Impeller 10 is press-fitted and fixed to one end (tip) of rotary shaft 51 in press-fit portion 13. Impeller 10 is composed of a conical hub plate 11 and a plurality of blades 12 fixed to the hub plate. Hub plate 11 and the plurality of blades 12 are made of an aluminum alloy and are integrally formed by machining.

[0018] A protrusion 11a (see FIG. 3B) is provided on the back surface of the hub plate 11. By rotating the impeller 10 and grinding down the protrusion 11a, it is possible to correct any imbalance in the rotor assembly 50 in conjunction with a balance ring 56, which will be described later. In addition, by forming the bearing from an aluminum alloy with high thermal conductivity, or a high-strength resin mixed with a material that enhances thermal conductivity, it is possible to improve the cooling performance of the bearing.

[0019] 1 and 2, fan casing 1 is molded from resin or the like and has a hollow conical shape. Fan casing 1 has a structure in which the upper and lower axial end faces are open, and houses part or all of impeller 10. Fan casing 1 is attached to upstream housing 20 so as to cover impeller 10 from above in the axial direction.

[0020] The electric blower 100 is positioned by inserting the mating portion 2 of the fan casing 1 into the claw protrusions 25 of the upstream housing 20, and by injecting an adhesive or the like into the mating portion 2, the fan casing 1 and the upstream housing 20 are fixed together and fluid leakage is prevented.

[0021] Fig. 4A is a front view of the upstream housing 20 as viewed from the upstream side. Fig. 4B is a cross-sectional view of the upstream housing 20. Fig. 4C is a side view of the upstream housing 20 with a portion cut away.

[0022] The upstream housing 20 includes a disk-shaped mounting portion 24 including a plane perpendicular to the axial direction, an upstream inner wall 21 extending axially downward from the outer periphery of the mounting portion 24, an upstream outer wall 22 provided radially outside the upstream inner wall 21 with a gap therebetween, and a first axial flow diffuser vane 23 that connects the upstream inner wall 21 and the upstream outer wall 22, decelerating the fluid and increasing its pressure.

[0023] That is, the upstream housing 20 is located on the impeller 10 side and radially outside the frame 70, and is provided with a first axial diffuser vane 23 between the upstream inner wall 21 and the upstream outer wall 22 located radially outside the upstream inner wall 21.

[0024] The mounting portion 24 is also formed with an upstream housing fitting protrusion 27 for fitting the bearing cap 4 therein, and holes 28 for fixing to the frame 70 with screws.

[0025] The outer peripheral surface of the upstream outer wall 22 is provided with claw protrusions 25 that protrude radially outward to connect to the fan casing 1, and claw protrusions 26 that protrude radially outward to connect to the downstream housing 30.

[0026] 5A is a front view of the downstream housing 30 as viewed from the upstream side, and FIG.

[0027] The downstream housing 30 includes a downstream outer wall 31 and a second axial diffuser vane 32 located radially inward of the downstream outer wall 31 to decelerate the fluid and increase its pressure.

[0028] That is, the downstream housing 30 is located on the opposite side of the upstream housing 20 from the impeller and radially outward of the frame 70, and is provided with the second axial diffuser vanes 32 between the frame 70 and the downstream outer wall 31 located radially outward of the frame 70. The radially inner side of the second axial diffuser vanes 32 is in contact with the frame 70.

[0029] The upstream housing 20 and the downstream housing 30 are fixed together by fitting the claw projections 26 of the upstream housing 20 into fitting holes 34 provided in the downstream protrusion 33 of the downstream housing 30. However, the upstream housing 20 and the downstream housing 30 may be fixed together by additional means such as adhesive, in addition to fitting the claw projections 26 into the fitting holes 34. As a result, the upstream outer wall 22 and the downstream outer wall 31 are integrated to form a substantially thick-walled cylindrical outer wall 41 (FIG. 1B) that extends in the axial direction. The outer wall 41 faces the radially outer side of the exhaust hole 73 (see FIG. 8A) of the frame 70, with a gap therebetween.

[0030] In this embodiment, the housing 3 is divided into the upstream housing 20 and the downstream housing 30, but may be configured as an integrated unit. The upstream housing 20 and the downstream housing 30 may be made of a material such as resin or aluminum alloy.

[0031] The bearing cap 4 is disposed on the impeller 10 side of the upstream housing 20 and the frame 70, and is provided with an inclination such that the diameter increases from the impeller 10 side toward the upstream housing 20 side so as to be continuous with 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 flow path 29 that guides the flow from the impeller 10 to the first axial diffuser vane 23.

[0032] The bearing cap 4 is fitted and fixed into the upstream housing fitting protrusion 27 so as to abut against the frame 70. The bearing cap 4 may be configured to be made up of multiple parts, for example, semicircular parts divided in the circumferential direction, and is held by the housing 3 and fixed by adhesive or the like.

[0033] 6A is a side view of rotor assembly 50. FIG. 6B is a cross-sectional view of rotor assembly 50.

[0034] The rotor assembly 50 comprises a rotating shaft 51, an impeller 10 fixed to one side of the rotating shaft 51, a rotor core 55 fixed to the other side of the rotating shaft 51, a balance ring 56 fixed to the other end of the rotating shaft 51, an upstream bearing 52 and a downstream bearing 53 located between the impeller 10 and the rotor core 55, and a spring 54 arranged between the upstream bearing 52 and the downstream bearing 53.

[0035] Because rotor assembly 50 rotates at a high speed, for example, 200,000 revolutions per minute, if the rotor is unbalanced, vibrations may occur or the bearings may be damaged during operation of electric blower 100. Therefore, in this embodiment, the rotational balance of rotor assembly 50 can be corrected by grinding impeller 10 and balance ring 56.

[0036] The impeller 10 is press-fitted and fixed to one end (tip) of the rotary shaft 51. The impeller 10 is composed of a hub plate 11 and multiple blades 12. The hub plate 11 and multiple blades 12 are made of an aluminum alloy and are integrally formed by machining. A convex portion 11a (see FIG. 3B) is provided on the back surface of the hub plate 11. By rotating the impeller 10 and machining the convex portion 11a, it is possible to correct imbalances in the rotor assembly 50 together with the balance ring 56. Furthermore, by forming the impeller 10 from an aluminum alloy with high thermal conductivity or a high-strength resin mixed with a material that enhances thermal conductivity, it is possible to improve the cooling performance of the bearing.

[0037] The rotating shaft 51 has a long, thin cylindrical shape and is made of a magnetic material such as iron. Note that the material of the rotating shaft 51 is not limited to the magnetic material described above, and it may be made of a non-magnetic material such as stainless steel (SUS). Furthermore, an upstream bearing 52 and a downstream bearing 53 are provided at approximately the center of the axial direction of the rotating shaft 51 and are spaced apart from each other in the axial direction.

[0038] 6B , a spring 54 is provided on the rotating shaft 51 between the upstream bearing 52 and the downstream bearing 53. The upstream bearing 52 is composed of, for example, an upstream bearing outer ring 52a, an upstream bearing inner ring 52b, and a plurality of rolling elements 52c, with the upstream bearing outer ring 52a fixed to a bearing housing portion 71 of the frame 70 and the upstream bearing inner ring 52b fixed to the rotating shaft 51. The spring 54 is a coil spring and biases the upstream bearing outer ring 52a and the downstream bearing outer ring 53a of the upstream bearing 52 and the downstream bearing 53 in directions separating them from each other. This prevents rattling in the bearings, thereby suppressing noise and vibration of the electric blower 100 and improving the supporting rigidity of the rotating shaft 51.

[0039] Rotor core 55 is made up of a permanent magnet with multiple magnetic poles, is fixed to the outer peripheral surface of rotating shaft 51, and is disposed axially downstream of downstream bearing 53. In addition, balance ring 56 is fixed to rotor core 55 axially downstream.

[0040] The balance ring 56 is made of a non-magnetic metal material such as brass. It has the same diameter as the rotor core 55 and is fixed to the rotating shaft 51 so as to contact the axial end face of the rotor core 55. The balance ring 56 is formed by cutting or the like, and functions to correct any imbalance in the rotor assembly 50 together with the impeller 10.

[0041] The rotor assembly 50 is inserted into the bearing housing 71 of the frame 70 from the upstream side in the axial direction and fixed therein by adhesive. The stator 60 is inserted into the stator housing 72 of the frame 70 from the downstream side in the axial direction and fixed therein by a set screw (not shown). At this time, the frame 70 is inserted into the upstream housing 20 and positioned. In this embodiment, the electric blower 100 fixes the upstream housing 20 and the stator 60 together with a screw (not shown), but other fixing methods such as adhesive, press fitting, welding, and integral molding may also be used.

[0042] 7A is a side view of the stator 60. FIG. 7B is a perspective view of the stator 60.

[0043] The stator 60 includes a stator core 61, an insulator 62 disposed on the stator core 61, a coil 63 wound around the insulator 62, and terminals 64. The insulator 62 is divided into an upstream insulator 62A and a downstream insulator 62B in a plane perpendicular to the rotation axis 51. A terminal 64 is inserted into a terminal box 65 of the insulator 62, and the coil 63 and the terminal 64 are electrically connected. The rotor core 55 is disposed on the inner periphery of the stator core 61, with the outer periphery thereof facing the inner periphery of the stator core 61 via an air gap 83. When a three-phase AC voltage is supplied from the terminals 64 to the coil 63, a rotating magnetic field is generated in the stator 60, and a rotational torque is generated in the rotor core 55. The stator core 61 is formed by laminating electromagnetic steel sheets whose main component is iron. The upstream insulator 62A and the downstream insulator 62B are formed of a resin such as polyethylene terephthalate (PET). The coil 63 is made of copper, aluminum alloy, or the like.

[0044] The insulator 62 has a plurality of protruding portions 66 that protrude in the axial direction away from the stator core 61 and are arranged side by side in the circumferential direction, and an axial end portion of each of the plurality of protruding portions 66 has a locking portion 67 that extends radially outward. In addition, a gap that communicates in the axial direction is formed between adjacent protruding portions 66 of the insulator 62.

[0045] The coil 63 is wound so as to be housed radially outward of the protruding portion 66 and closer to the stator core 61 in the axial direction than the locking portion 67, thereby positioning the coil 63. In other words, the protruding portion 66 positions the coil 63 radially outward.

[0046] Fig. 8A is a perspective view showing the appearance of the frame 70. Fig. 8B is a cross-sectional view of the frame 70 as seen from the side. Fig. 8C is a perspective view of the frame 70 with a part of the stator storage section 72 cut away.

[0047] The frame 70 is open on both sides in the axial direction, and has a cylindrical bearing housing section 71 on the upstream side (impeller side) that houses a pair of bearings (upstream bearing 52 and downstream bearing 53), and a cylindrical stator housing section 72 on the downstream side (opposite the impeller side) that has a larger diameter than the bearing housing section 71 and houses part of the bearing housing section 71 and the stator 60. A disk section 75 connects the end of the stator housing section 72 on the upstream side in the axial direction (impeller side) to the middle part of the bearing housing section 71 in the axial direction.

[0048] Furthermore, the frame 70 is provided with a plurality of ribs 76 that connect the bearing housing 71, the disk portion 75, and the stator housing 72 and extend radially. The upper peripheral surface (the peripheral surface on the impeller side) of the stator housing 72 is provided with a plurality of exhaust holes 73. The exhaust holes 73 are formed at equal intervals in the circumferential direction on the side wall peripheral surface. Furthermore, a stator abutment portion 72a that protrudes radially inward is formed on the inner surface on the upstream side of the stator housing 72. Furthermore, the stator housing 72 is formed with screw holes 74 for fixing to the stator core 61 with screws.

[0049] The disk portion 75 of the frame 70 is provided with a thread groove 77, and a screw (not shown) is threaded into the thread groove 77 through the hole 28 in the upstream housing to fix the frame 70 and the upstream housing 20. The frame 70 is made of an aluminum alloy or a magnesium alloy. Aluminum or magnesium alloys are lighter and have higher thermal conductivity than stainless steel (Steel Use Stainless: SUS).

[0050] Fig. 9A is an external view of the rotor support assembly 200. Fig. 9B is a cross-sectional view of the rotor support assembly 200 shown in Fig. 9A as viewed from the side. Fig. 9C is an enlarged view of part IX in Fig. 9B. Fig. 9D is a cross-sectional view taken along line XX in Fig. 9A. Fig. 10A is a perspective view of the upstream insulator 62A as viewed from the impeller side. Fig. 10B is a perspective view of the upstream insulator 62A as viewed from the opposite side to the impeller.

[0051] Rotor support assembly 200 is constructed by combining rotor assembly 50 and stator 60 with frame 70. Rotor assembly 50 is inserted into bearing housing portion 71 of frame 70 from the axially upper side, and upstream bearing 52 and downstream bearing 53 are adhesively fixed to the inner surface of bearing housing portion 71.

[0052] The stator 60 is inserted into the stator storage portion 72 of the frame 70 from the axially lower side, and the upstream insulator 62A is brought into contact with the stator contact portion 72a, and fixed using set screws.

[0053] The stator 60 and the rotatable rotor core 55 (rotor assembly 50) arranged inside the stator 60 are covered by a frame 70 from one end of the upper part of the upstream bearing 52 of the rotor assembly 50 to the lower part of the stator core 61.

[0054] The stator core 61 is composed of an annular yoke 86 that contacts the inner periphery of the frame 70, a recess 84 formed by cutting out a portion of the outer periphery of the yoke 86, and a plurality of teeth 81 that protrude radially inward from the yoke 86. The plurality of teeth 81 are arranged at equal intervals in the circumferential direction, with slots 82 between adjacent teeth 81. Insulators 62 are arranged on the stator core 61 that contacts the slots 82 so as to cover the surface, and coils 63 are wound around the teeth 81 via the insulators 62. In this embodiment, the stator core 61 is configured with three-phase, three-slot concentrated winding.

[0055] Insulator 62 is housed in stator core 61, and at a portion radially inward of protrusion 66, has guide portions 87 that are continuous with protrusion 66 and have the same arc shape as protrusion 66, and that guide coil 63, and support portions 88 that abut against teeth 81, and guide portions 87 and support portions 88 are connected via openings 89. Guide portions 87 reliably guide coil 63 radially outward of bearing housing portion 71, and support portions 88 prevent protrusion 66 and guide portions 87 from collapsing radially inward and being deformed by the tension of coil 63. This prevents interference between bearing housing portion 71 and stator 60, shortens the distance between rotor core 55 and downstream bearing 53, reduces whirling of rotating shaft 51, and improves bearing life. Furthermore, the presence of opening 89 allows the amount of material used in insulator 62 to be reduced, contributing to the weight reduction of electric blower 100, and since support portion 88 is connected to both ends of guide portion 87, rigidity can be effectively increased and sufficient strength can be ensured, compared to the case where no opening is present.

[0056] <Air flow inside the electric blower 100> Next, we will explain the air flow inside electric blower 100. When rotor support assembly 200 shown in Figure 1B is driven to rotate impeller 10, a main flow F1 is generated from the upstream side to the downstream side.

[0057] The main flow F1 is air that flows in through the air inlet 90 of the fan casing 1 and into the impeller 10. In the case of a mixed-flow impeller, the inflowing air is pressurized by the blades inside the impeller 10, imparting a radial component to the flow drawn in from the axial direction, generating a flow that has a radial component and is tilted from the axial direction. Thus, at the impeller outlet 14, the rotational component and the axial component combine to form a flow that flows out of the impeller 10.

[0058] The main stream F1 flowing out from the impeller 10 passes through the first axial diffuser vane 23 and the second axial diffuser vane 32, where the rotational velocity component is converted into a linear velocity component, thereby reducing the velocity and increasing the static pressure, and the air is then exhausted from the exhaust port 91. That is, the impeller 10, the first axial diffuser vane 23, and the second axial diffuser vane 32 form a first flow path through which the air (main stream F1) flowing in from the air inlet port 90 flows.

[0059] Here, the flow at the outlet of the first axial diffuser vane 23 is a high-speed flow and has a lower pressure than the exhaust port 91. Because the opening 79 of the frame 70 is close to the outlet of the first axial diffuser vane 23, the pressure at the opening 79 is equivalent to that at the outlet of the first axial diffuser vane 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 hole 73 of the frame 70. In other words, air (cooling flow F2) passes between the opening 79 of the frame 70, the inside of the motor, and the exhaust hole 73 of the frame 70, forming a second flow path that merges with the first flow path.

[0060] The impeller 10 and the bearing housing 71 of the frame 70 are made of aluminum or magnesium alloy, which has high thermal conductivity. Therefore, the upstream bearing 52 and the downstream bearing 53 are cooled by heat transfer as the main flow F1 flows over the outer surface of the stator housing 72 of the frame 70. Note that the upstream bearing 52 close to the impeller 10 is made of a highly thermally conductive material (for example, an aluminum alloy), which cools the rotating impeller 10, and the impeller side of the rotating shaft 51 is cooled by heat transfer, thereby cooling the upstream bearing 52.

[0061] Next, the cooling flow F2 will be described. The cooling flow F2 is a flow of fluid (cooling air) that cools the rotor support assembly 200, and is drawn in through the openings 79 of the frame 70, passes through the stator core 61, the coils 63 arranged in the circumferential direction, and so on, and flows toward the exhaust holes 73 of the frame 70.

[0062] The cooling flow F2 is then discharged through the exhaust holes 73 to a gap between the frame 70 and the upstream outer wall 22. The fluid discharged between the frame 70 and the upstream outer wall 22 flows toward the exhaust port 91, merges with the main flow F1 upstream of the second axial diffuser vane 32 or in the inter-blade flow passage of the second axial diffuser vane 32, and is discharged at the opening 79 of the frame 70.

[0063] That is, the amount of air passing through the second axial diffuser vane 32 is increased by the amount of air flow of the cooling flow F2 relative to the amount of air flow of the main flow F1 passing through the first axial diffuser vane 23. This increase in air flow reduces flow separation on the second axial diffuser vane 32, thereby enabling higher efficiency.

[0064] As cooling flow F2 travels from opening 79 in frame 70 toward exhaust hole 73 in frame 70, it branches into recessed flow passage 85, air gap 83, and slot 82 in stator core 61, and cools stator core 61, rotor core 55, and coil 63, and then collides with and cools frame 70 and downstream bearing 53. After cooling, cooling flow F2 merges with main flow F1 to exchange heat, and the flow combined with main flow F1 is exhausted to the outside, cooling the motor.

[0065] <Characteristic configuration and effects of electric blower 100> Next, the characteristic configuration and effects of the electric blower 100 will be described. In the rotor assembly 50 of this embodiment, a pair of bearings (upstream bearing 52, downstream bearing 53) is provided approximately in the center and inserted and fixed into a cylindrical bearing housing 71. As a result, the inner circumferential surface of the bearing housing 71, into which the bearings (upstream bearing 52, downstream bearing 53) fit, is configured as a single surface, so that the concentricity of the bearings (upstream bearing 52, downstream bearing 53) can be ensured with high precision. This suppresses tilt of the rotating shaft 51 and abnormal surface pressure on the bearings, thereby improving the bearing life.

[0066] Frame 70 is configured with bearing housing 71 and stator housing 72 integrally formed. This allows the inner circumferential surfaces of bearing housing 71 and stator housing 72 to be machined with high concentricity, and allows upstream bearing 52, downstream bearing 53, rotor core 55, and stator 60 to be assembled with high concentricity. This reduces the electromagnetic force acting on rotor core 55 due to eccentricity, reduces the load on upstream bearing 52 and downstream bearing 53, and improves bearing life.

[0067] 9C, the insulator 62 has a protruding portion 66 that protrudes in the axial direction, and the coil 63 is wound radially outward from the protruding portion 66. In addition, the protruding portion 66 is provided at a position that includes at least a portion (the end portion opposite the impeller) of the bearing housing portion 71. In other words, at the position where the bearing housing portion 71 and the protruding portion 66 overlap in the axial direction, the minimum inner radius Ri of the protruding portion 66 is larger than the maximum outer radius Rc of the bearing housing portion 71. In other words, Ri > Rc. This prevents interference between the stator 60 and the bearing housing portion 71, and allows the axial position of the stator core 61 to be closer to the downstream bearing 53.

[0068] Since the rotor core 55 is disposed to face the stator core 61, the rotor core 55 can also be brought close to the downstream bearing 53. The load due to the mass imbalance is applied to the rotor core 55 and the balance ring 56 at the center of gravity m r (FIG. 6B), and the center of gravity position m of the impeller 10 i(Fig. 6B) The distance from each bearing (upstream bearing 52, downstream bearing 53) to each center of gravity m r , m i The shorter the distance between rotor core 55 and downstream bearing 53, the smaller the moment load applied to each bearing (upstream bearing 52, downstream bearing 53), improving bearing life. Also, the axial length of rotating shaft 51 can be shortened, making electric blower 100 smaller and lighter. In other words, by shortening the distance between rotor core 55 and downstream bearing 53, bearing life can be improved and electric blower 100 can be made smaller and lighter.

[0069] The protrusions 66 are provided at equal intervals in the circumferential direction, with axially communicating gaps between them. This allows the nozzle of a winding machine to be inserted into the slots 82 from the inner diameter side when winding the coil 63, making it suitable for automated manufacturing. The axially communicating gaps also increase the flow path cross-sectional area of ​​the cooling flow F2 flowing in from the downstream side, improving cooling of the electric blower 100. After passing through the air gap 83 in the axial direction, the flow path can be configured to pass radially from the space surrounded by the downstream bearing 53, the protrusions 66, and the rotor core 55 through the gaps, improving cooling, particularly of the downstream bearing 53 and the rotor core 55. This reduces the bearing temperature and improves bearing life.

[0070] The axially upstream end of the stator housing 72 and the middle (intermediate portion) of the bearing housing 71 are connected by a disk portion 75. The bearing housing 71 is connected at a connection point 78 ( FIG. 8B ), and specifically, is located between the bearings (upstream bearing 52, downstream bearing 53) in the axial direction, but does not overlap with the bearings (upstream bearing 52, downstream bearing 53). This allows the coil 63 to be housed in the space surrounded by the bearing housing 71, stator housing 72, and disk portion 75, preventing interference between the stator 60 and frame 70, shortening the distance between the rotor core 55 and downstream bearing 53, and improving bearing life.

[0071] As shown in FIG. 9C, the minimum outer radius R b is the outer radius R of the rotor core 55 mIt is made larger than R b >R m As a result, when the rotor assembly 50 is inserted into the bearing housing portion 71, assembly can be performed without the rotor core 55 interfering with the bearing housing portion 71.

[0072] The rotor assembly 50 can correct unbalances while all components are fixed, reducing the loads on the upstream bearing 52 and the downstream bearing 53, thereby improving the bearing life. b ≦R m In this case, the rotor core 55 and balance ring 56 must be inserted and fixed into the bearing housing 71 without being inserted, and then the rotor core 55 and balance ring 56 must be fixed. Alternatively, without the impeller 10 being inserted, the non-rotor core side must be inserted and fixed from the axial downstream side of the bearing housing 71, and then the impeller 10 must be fixed. In this case, the imbalance can only be corrected without any parts to be fixed later, which increases the bearing load and shortens the bearing life.

[0073] Inner radius R of stator core 61 s is the rotor outer radius R m The minimum outer radius R of the bearings (upstream bearing 52, downstream bearing 53) is larger than b That is, R b >R s >R m First, R s >R m By satisfying the relationship, an internal rotor type rotating electric machine can be constructed. An internal rotor type rotating electric machine can reduce the radius of the rotating part and can suppress centrifugal force, so it is suitable for high speed rotation applications. Next, R b >R s By satisfying this relationship, the air gap 83 is positioned so as to overlap the downstream bearing 53 in the radial direction, and a flow path configuration is created in which the cooling flow F2 passing through the air gap 83 in the axial direction collides with the downstream bearing 53, thereby promoting cooling of the downstream bearing 53. This makes it possible to reduce the bearing temperature and improve the bearing life.

[0074] FIG. 11 shows the distance L between the downstream bearing 53 and the rotor core 55. d 10 is a diagram showing the transition of the results of electromagnetic field analysis of eddy current loss in the downstream bearing 53 and the bearing housing 71 when the temperature is changed.

[0075] If the rotor core 55 and downstream bearing 53 are placed close to each other, part of the magnetic flux from the magnet passes through the downstream bearing 53 and bearing housing 71, causing eddy current loss. This can cause the downstream bearing 53 to heat up and shorten its lifespan. However, by separating the rotor core 55 and downstream bearing 53 and increasing the magnetic resistance of the magnetic path passing through the downstream bearing 53, the magnetic flux passing through the downstream bearing 53 can be reduced, thereby reducing the eddy current.

[0076] As shown in the figure, the distance L between the downstream bearing 53 (the bearing on the opposite side of the impeller) and the rotor core 55 d When the distance Ld between the downstream bearing 53 and the rotor core 55 (see FIG. 6B) is increased from 1 to 4 times the width Gap of the air gap 83, the eddy current loss is significantly reduced, but when it is increased from 4 to 8 times, the reduction amount becomes smaller. d By satisfying the relationship of >4Gap, eddy current loss can be reduced.

[0077] A load is generated in the rotor assembly 50 due to the mass imbalance, and the upstream bearing 52 and downstream bearing 53 that support the rotating shaft 51 are subjected to a radial load. As a result, the bearing housing 71 is also subjected to a load in the radial direction via the upstream bearing 52 and downstream bearing 53. This load causes the bearing housing 71 to deform and whirl, increasing the whirl of the rotating shaft 51 and shortening the bearing life.

[0078] Because the bearing housing 71 is fixed by the thread groove 77 of the disk portion 75, deformation can be minimized by shortening the distance between the upstream bearing 52 and the downstream bearing 53, which receive the load from the connection point 78 between the disk portion 75 and the bearing housing 71. The bearing housing 71 is connected to the disk portion 75 at a position between the upstream bearing 52 and the downstream bearing 53. This allows the distances from the connection point 78 between the disk portion 75 and the bearing housing 71 to each bearing (the upstream bearing 52 and the downstream bearing 53) to be approximately the same, thereby increasing the radial rigidity of the bearing housing 71 when a load is applied to the contact point with the upstream bearing 52 or the downstream bearing 53. Reducing the amount of deformation reduces whirling of the rotating shaft and improves bearing life. Furthermore, the frame 70 includes a rib 76 that connects the bearing housing 71, the disk portion 75, and the stator housing 72 to the axial downstream side (opposite the impeller) of the disk portion 75. This allows the rigidity of the bearing housing portion 71 to be increased with a small increase in mass compared to thickening the entire frame 70, thereby improving the bearing life.

[0079] In FIG. 6B, the unbalanced load of the impeller 10 at the rated rotation speed is K i , the unbalanced load of the rotor core 55 and the balance ring 56 is K r The distance between the axial center of the upstream bearing 52 and the axial center of the downstream bearing 53, that is, the bearing span, is L c , the distance from the axial center of the upstream bearing 52 to the center of gravity m of the impeller 10 i The distance to the impeller, i.e., the impeller overhang, is L a , the distance from the axial center of the downstream bearing 53 to the center of gravity m of the rotor core 55 and the balance ring 56 r The distance to the rotor, i.e., the rotor overhang, is L b When the radial load P of the upstream bearing 52 is f and the radial load P of the downstream bearing 53 r is given by the following equation (1).

[0080]

number

[0081] As shown in equation (1), the bearing span L c By lengthening the length, the radial load P f , P r However, the bearing span L c Increasing the length of the bearing radial load P f and P r is the bearing span L c Since it is inversely proportional to the bearing span L c If the bearing span L is increased by a certain amount, the reduction in bearing radial load becomes smaller. c It is preferable to have a structure that reduces the bearing radial load while keeping the length as short as possible.

[0082] In this embodiment, the rotor overhang amount L b The distance m between the axial center of the downstream bearing 53 and the center of gravity of the rotor core 55 and the balance ring 56 is r However, the balance ring 56 may be included in the rotor core 55.

[0083] FIG. 12 shows the axial length L of the rotor assembly 50. ax and the bearing span L of the evaluation function obtained by multiplying the larger value of the radial loads of the pair of bearings (upstream bearing 52, downstream bearing 53). c FIG. 10 is a diagram showing the transition when the value of

[0084] Axial length L of rotor assembly 50 ax Since the smaller the bearing radial load and the smaller the load, the better. Therefore, a structure that reduces the evaluation function obtained by multiplying these is preferable. Bearing span L c As the axial length L of the rotor assembly 50 increases, ax increases proportionally and the bearing radial load decreases inversely, so the performance function is a downward convex curve. The bearing span L at which this performance function is minimized is c is 2L a ≦L c ≦3Lb It is within the range of 2L. b ≦L c ≦3L a The bearing span L c By selecting the above, the bearing radial load can be effectively reduced with a rotor assembly 50 having a shorter axial length, and the electric blower 100 can be made smaller and lighter while improving the bearing life.

[0085] A connection point 78 between the bearing housing portion 71 and the disk portion 75 is located perpendicular to the axial direction and downstream (opposite the impeller) of a midplane Sm (FIG. 9B) between the pair of bearings (upstream bearing 52, downstream bearing 53). The rib 76 is provided downstream (opposite the impeller) of the connection point 78.

[0086] In this example, the impeller overhang amount L a Rotor overhang L b is larger, which raises concerns about a deformation mode in which the downstream axial end of the rotor assembly 50 whirls. Therefore, by further increasing the radial rigidity of the bearing housing 71 at the position where it is fitted with the downstream bearing 53, this deformation mode can be suppressed, the bearing radial load can be reduced, and the bearing life can be improved. The connection point 78 and the rib 76 can be located so as not to overlap the axial center (mid-plane Sm) of the bearing housing 71 and so as to be closer to the side with the larger overhang (in this embodiment, the axial downstream side, that is, the side opposite the impeller), thereby improving the bearing life.

[0087] <Configuration of the electric vacuum cleaner 300> The electric blower 100 according to this embodiment is suitable for use as a fan motor for an electric vacuum cleaner, for example. The configuration of an electric vacuum cleaner 300 incorporating the electric blower 100 according to this embodiment will be described. Fig. 13 is a perspective view showing the appearance of the electric vacuum cleaner 300 according to this embodiment of the present invention.

[0088] 13, electric vacuum cleaner 300 includes vacuum cleaner body 301 equipped with electric blower 100 and dust collection unit 302 that stores dust collected by the suction force generated by electric blower 100, extension tube 306 having one end connected to vacuum cleaner body 301 and communicating with dust collection unit 302, and suction body 307 connected to the other end of extension tube 306. Vacuum cleaner body 301 also includes battery unit 303 as a driving source, grip unit 304, and switch unit 305 provided on grip unit 304 that turns electric blower 100 on and off.

[0089] When switch unit 305 is operated, electric blower 100 housed in vacuum cleaner body 301 starts operating, and a suction airflow is generated in suction body 307. The suction airflow sucks dust on the floor surface through suction body 307. The sucked dust passes through extension tube 306 and is collected in dust collection unit 302 of vacuum cleaner body 301.

[0090] The electric vacuum cleaner is not limited to the stick-type vacuum cleaner shown in the figure, but can also be applied to handheld vacuum cleaners, canister vacuum cleaners (cylinder vacuum cleaners), etc. The invention can also be applied to corded vacuum cleaners with a similar configuration. [Example]

[0091] Next, a second embodiment will be described with reference to Fig. 14. Fig. 14 is a cross-sectional view of an electric blower 100 according to a second embodiment of the present invention. Components common to those in the first embodiment are given the same reference numerals, and detailed descriptions thereof will be omitted.

[0092] In the second embodiment, the configurations of the rotary shaft 51, upstream bearing 52, downstream bearing 53 and bearing housing portion 71 of the rotor assembly 50 are different from those of the first embodiment, and are replaced by a bearing-integrated rotor unit 110.

[0093] The bearing storage section 71 is divided into an outer peripheral section 71A which is integrally formed with the stator storage section 72 and the disc section 75, and an inner peripheral section 71B which is inserted and fixed to the inner peripheral side (radially inward) of the outer peripheral section 71A and has two outer ring grooves 111 (upstream outer ring groove 111A, downstream outer ring groove 111B) machined on the inner peripheral side.

[0094] Two inner ring grooves 112 (upstream inner ring groove 112A, downstream inner ring groove 112B) are machined on the outer periphery (radially outward) of the rotating shaft 51 at positions radially opposite the two outer ring grooves 111, and multiple rolling elements 113 (upstream rolling elements 113A, downstream rolling elements 113B) are arranged in the space formed by the inner ring grooves 112 and the outer ring grooves 111.

[0095] The upstream inner ring groove 112A, the upstream rolling element 113A, and the upstream outer ring groove 111A form the upstream bearing 52, and the downstream inner ring groove 112B, the downstream rolling element 113B, and the downstream outer ring groove 111B form the downstream bearing 53.

[0096] According to this embodiment, by using bearing-integrated rotor unit 110, it is possible to improve the concentricity of the pair of bearings 52, 53. Furthermore, according to this embodiment, since inner ring groove 112 is machined in rotating shaft 51, it is possible to improve the bending rigidity of rotor assembly 50 compared to embodiment 1 in which upstream-side bearing inner ring 52b, downstream-side bearing inner ring 53b and rotating shaft 51 are provided separately. As a result, it is possible to reduce whirling of the rotating shaft and improve bearing life.

[0097] <Effects of Examples 1 and 2> According to the embodiments described above, it is possible to reduce whirling and load by improving the assembly precision of the rotating part and its support part of the electric blower, and this reduction effect can be achieved without significantly increasing the size and mass of the rotating part and support part. As a result, it is possible to provide a small and lightweight electric blower with improved bearing life, and an electric vacuum cleaner equipped with the same.

[0098] The present invention is not limited to the above-described embodiments, but includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations. [Explanation of symbols]

[0099] 1...fan casing, 3...housing, 4...bearing cap, 10...impeller, 20...upstream housing, 21...upstream inner wall, 22...upstream outer wall, 23...first axial diffuser vane, 29...flow path, 30...downstream housing, 31...downstream outer wall, 32...second axial diffuser vane, 50...rotor assembly, 51...rotating shaft, 52...upstream bearing, 52a...upstream bearing outer ring, 52b...upstream bearing inner ring, 52c...rolling elements, 53...downstream bearing, 53a...downstream bearing outer ring, 53b...downstream bearing inner ring, 55...rotor core, 56...balance ring, 60...stator, 61...stator core, 62...insulator, 62A...upstream insulator, 62B...downstream insulator, 63...coil, 66...protrusion, 67...locking portion, 70...frame, 71... Bearing storage portion, 71A...outer peripheral portion, 71B...inner peripheral portion, 72...stator storage portion, 72a...stator abutment portion, 73...exhaust hole, 75...disk portion, 76...rib, 78...connection point, 79...opening, 81...teeth, 82...slot, 83...air gap, 84...recess, 85...recess flow path, 86...yoke, 87...guiding portion, 88...support portion, 89...opening, 90...air intake port, 91...exhaust port , 100... electric blower, 111... outer ring groove, 111A... upstream outer ring groove, 111B... downstream outer ring groove, 112... inner ring groove, 112A... upstream inner ring groove, 112B... downstream inner ring groove, 113... rolling element, 113A... upstream rolling element, 113B... downstream rolling element, 200... rotating element support assembly, 300... electric vacuum cleaner, 301... vacuum cleaner main body, 302... dust collecting part, 306... extension pipe, 307... suction body

Claims

1. a rotor assembly including a rotor core, a rotary shaft provided in the rotor core, an impeller fixed to the rotary shaft, and a pair of bearings positioned between the impeller and the rotor core and rotatably supporting the rotary shaft; a stator including a stator core, an insulator disposed on the stator core, and a coil wound around the stator core via the insulator, the stator including a portion of the rotor assembly and constituting an electric motor together with the rotor core; a frame covering the rotor assembly and the stator; an upstream housing positioned on the impeller side and radially outward of the frame, the upstream housing including a first axial flow diffuser vane between an upstream inner wall and an upstream outer wall positioned radially outward of the upstream inner wall; a downstream housing positioned on an opposite side of the upstream housing from the impeller and radially outward of the frame, the downstream housing including a second axial flow diffuser vane between the frame and a downstream outer wall positioned radially outward of the frame; a fan casing fixed to the upstream housing, covering the impeller, and having an air inlet through which air flows, The inner radius R of the stator core ｓ , the outer radius R of the bearing ｂ , the outer radius R of the rotor core ｍ is R ｂ >R ｓ >R ｍ Fulfilling the relationship, the frame comprises: a bearing housing section that houses the pair of bearings; a stator housing section that has an opening on the side opposite to the impeller and is larger in diameter than the bearing housing section, and that houses a part of the bearing housing section and the stator; a disk section that connects the impeller side end of the stator housing section to an axial intermediate part of the bearing housing section; and ribs that connect the bearing housing section, the disk section, and the stator housing section, the insulator has a plurality of protruding portions that protrude in the axial direction, are arranged in a row in the circumferential direction, and have the coil positioned radially outward, and that contain the end of the bearing storage section on the side opposite the impeller, gaps that are formed between adjacent protruding portions and communicate in the axial direction, guide portions that are connected to the protruding portions and guide the coil, and support portions that abut against the teeth of the stator core, and the guide portions and the support portions are connected via openings.

2. The electric blower according to claim 1, a first flow path through which air flowing in from the air inlet flows is formed in the impeller, the first axial flow diffuser vane, and the second axial flow diffuser vane; an exhaust hole that opens toward the first flow path is provided on an upper peripheral surface of the stator storage portion; an electric blower, wherein a second flow path through which air passes and merges with the first flow path is formed between the opening of the stator housing section, the interior of the electric motor, and the exhaust hole.

3. The electric blower according to claim 1, The pair of bearings includes an upstream bearing located on the impeller side and a downstream bearing located on the opposite side to the impeller, The distance between the rotor core and the downstream bearing is L ｄ When the distance between the stator core and the rotor core is Gap, L ｄ 2. The electric blower according to claim 1, wherein the electric blower is configured to satisfy the relationship: .gt. 4Gap.

4. The electric blower according to claim 1, The pair of bearings includes an upstream bearing located on the impeller side and a downstream bearing located on the opposite side to the impeller, The distance from the axial center of the upstream bearing to the center of gravity of the impeller is called the impeller overhang amount L ａ The distance from the axial center of the downstream bearing to the center of gravity of the rotor core is defined as the rotor overhang amount L ｂ year, The connection point between the bearing housing portion and the disk portion is perpendicular to the axial direction and is located at a position that does not overlap with the mid-plane of the pair of bearings, and the impeller overhang amount L ａ , the rotor overhang amount L ｂ The maximum limit is set at the larger of the two. The electric blower is characterized in that the rib is provided on the opposite side of the impeller in the axial direction from the disc portion.

5. The electric blower according to claim 1, The pair of bearings includes an upstream bearing located on the impeller side and a downstream bearing located on the opposite side to the impeller, The distance from the axial center of the upstream bearing to the center of gravity of the impeller is called the impeller overhang amount L ａ The distance from the axial center of the downstream bearing to the center of gravity of the rotor core is defined as the rotor overhang amount L ｂ The distance between the axial center of the upstream bearing and the axial center of the downstream bearing is defined as a bearing span L ｃ When The impeller overhang amount L ａ , the rotor overhang amount L ｂ , the bearing span L ｃ is 2L ａ ≦L ｃ ≦3L ｂ An electric blower characterized in that it is configured to satisfy the relationship:

6. The electric blower according to claim 1, The pair of bearings includes an upstream bearing located on the impeller side and a downstream bearing located on the opposite side to the impeller, The distance from the axial center of the upstream bearing to the center of gravity of the impeller is called the impeller overhang amount L ａ The distance from the axial center of the downstream bearing to the center of gravity of the rotor core is defined as the rotor overhang amount L ｂ The distance between the axial center of the upstream bearing and the axial center of the downstream bearing is defined as a bearing span L ｃ When The impeller overhang amount L ａ , the rotor overhang amount L ｂ , the bearing span L ｃ is 2L ｂ ≦L ｃ ≦3L ａ An electric blower characterized in that it is configured to satisfy the relationship:

7. The electric blower according to claim 1, the bearing housing portion is composed of an outer peripheral portion that is integrally formed with the stator housing portion and the disk portion, and an inner peripheral portion that is inserted and fixed radially inside the outer peripheral portion and that is integrally formed with outer rings of the pair of bearings, The rotating shaft is integrally formed with the inner rings of the pair of bearings, The electric blower is characterized in that the rotating shaft and the inner peripheral portion constitute a bearing-integrated rotor unit.

8. An electric vacuum cleaner comprising: a vacuum cleaner body having an electric blower and a dust collecting unit that collects dust collected by suction force generated by the electric blower; an extension pipe having one end connected to the vacuum cleaner body and communicating with the dust collecting unit; and a suction nozzle body connected to the other end of the extension pipe, 8. An electric vacuum cleaner, wherein the electric blower is the electric blower according to any one of claims 1 to 7.

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