Electric blower

Abstract

To provide an electric blower capable of sufficiently cooling a rotor core, a rotor coil, and a commutator.SOLUTION: An electric blower includes a shaft, a commutator, a rotor core, a rotor coil, a first insulator in contact with one side end surface of the rotor core, a second insulator in contact with the other side end surface of the rotor core, a blower unit configured to send outside air into the frame, and an exhaust port configured to discharge the air sent by the blower unit. A notch is formed in an outer peripheral portion of the shaft. The notch is formed across a region to which a bearing on the anti-blower side is attached, a region to which the commutator is attached, a region to which the first insulator is attached, a region to which the rotor core is attached, and a region to which the second insulator is attached.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an electric blower for use in an electrical device. [Background technology]

[0002] Heat generated by the rotor during operation of an electric blower can result in energy loss or reduced durability, so electric blowers require a means for cooling the rotor.

[0003] As a technology for cooling the rotor of an electric blower, Patent Document 1 below discloses a technique in which a through hole is provided in the rotor shaft to form an air passage, allowing air to flow into the inside of the electric blower. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-115697 Summary of the Invention [Problem to be solved by the invention]

[0005] The conventional technology described in Patent Document 1 has a problem in that it is difficult to sufficiently cool the rotor core, rotor coil, and commutator.

[0006] The present disclosure has been made to solve the above-mentioned problems, and an object of the present disclosure is to provide an electric blower that is capable of sufficiently cooling a rotor core, a rotor coil, and a commutator. [Means for solving the problem]

[0007] The electric blower according to the present disclosure includes a shaft, a commutator attached to the shaft, a rotor core attached to the shaft, a rotor coil wound in a slot of the rotor core, a first insulator abutting one end surface of the rotor core, a second insulator abutting the other end surface of the rotor core, a blower unit attached to the shaft and configured to send external air into a frame that houses the shaft, the rotor core, the rotor coil, the first insulator, and the second insulator, and an exhaust port through which the air sent by the blower unit is discharged. A notch is formed in the outer periphery of the shaft. The notch is formed over an area where a bearing on the non-blower side is attached, an area where the commutator is attached, an area where the first insulator is attached, an area where the rotor core is attached, and an area where the second insulator is attached. [Effects of the Invention]

[0008] According to the electric blower according to the present disclosure, it is possible to sufficiently cool the rotor core, the rotor coil, and the commutator. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a perspective view showing the appearance of an electric blower according to a first embodiment. [Figure 2] 1 is a cross-sectional side view of an electric blower according to a first embodiment. [Figure 3] FIG. 1 is a perspective view showing a state before a motor unit of an electric blower according to a first embodiment is assembled. [Figure 4] 1 is a perspective view showing the appearance of a rotor according to a first embodiment. [Figure 5] FIG. 2 is a perspective view showing the rotor of the first embodiment in a state before assembly. [Figure 6] 1 is a cross-sectional view of a rotor according to a first embodiment, viewed from the side. [Figure 7] 1 is a cross-sectional view of a rotor core according to a first embodiment, viewed from the front. [Figure 8]2 is a perspective view of the first insulator of the first embodiment as viewed from the pipe-shaped insulating portion side. FIG. [Figure 9] 3 is a perspective view of the first insulator of the first embodiment as viewed from the opposite side of the pipe-shaped insulating portion. FIG. [Figure 10] 2 is a cross-sectional view showing the air flow when the electric blower of the first embodiment is viewed from the side. FIG. [Figure 11] FIG. 3 is a cross-sectional view showing a first modified example of the electric blower of the first embodiment. [Figure 12] FIG. 10 is a perspective view of a first insulator in a second modification of the first embodiment, viewed from the opposite side of the pipe-shaped insulating portion. [Figure 13] FIG. 10 is a front view of the first insulator in the second modification of the first embodiment, viewed from the opposite side of the pipe-shaped insulating portion. [Figure 14] FIG. 10 is a cross-sectional view of a rotor according to a second modified example of the first embodiment, as viewed from the side. [Figure 15] FIG. 10 is a diagram showing the distribution of magnetic field lines in a cross section of a rotor core of an electric blower according to a conventional technique, which is a comparative example. [Figure 16] FIG. 10 is a diagram showing the distribution of magnetic lines of force in a cross section of a rotor core in a third modified example of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments will be described with reference to the drawings. Common or corresponding elements in each drawing are designated by the same reference numerals, and descriptions thereof will be simplified or omitted. Note that the configurations shown in the following embodiments are examples of the technical ideas of the present disclosure, and may be combined with other known technologies, or multiple technical ideas may be combined. Furthermore, the configurations disclosed in the following embodiments may be partially omitted or modified without departing from the gist of the present disclosure.

[0011] Embodiment 1 FIG. 1 is a perspective view showing the appearance of electric blower 100 according to the first embodiment. FIG. 2 is a cross-sectional view of electric blower 100 according to the first embodiment as seen from the side. Electric blower 100 is used in electrical appliances such as vacuum cleaners, for example. As shown in FIGS. 1 and 2, electric blower 100 is made up of motor section 101, which is a commutator motor, and blower section 102.

[0012] 3 is a perspective view showing a state before assembly of motor unit 101 of electric blower 100 according to embodiment 1. As shown in FIG. 3, motor unit 101 is made up of rotatably provided rotor 103, stator 104, frame 13, and brush unit 105.

[0013] Frame 13 is a member that forms the outer shell of electric blower 100. Frame 13 is formed, for example, by pressing an aluminum alloy. As shown in FIG. 3, frame 13 has a body portion 13b, a flange portion 13c, and a housing portion 13a. Body portion 13b is a cylindrical member that is open at one end and has a bottom. Flange portion 13c is a flange-shaped portion formed on the open side of body portion 13b and has a larger diameter than body portion 13b. Housing portion 13a is a portion formed at the bottom of body portion 13b and has a smaller diameter than body portion 13b. A plurality of exhaust ports 13d are formed in the side portion of body portion 13b.

[0014] FIG. 4 is a perspective view showing the appearance of rotor 103 according to the first embodiment. FIG. 5 is a perspective view showing the rotor according to the first embodiment before assembly. FIG. 6 is a cross-sectional view of the rotor according to the first embodiment as seen from the side. As shown in FIGS. 4, 5, and 6, rotor 103 is composed of shaft 1, rotor core 2, rotor coil 3, commutator 4, anti-blower side bearing 5, blower side bearing 6, first insulator 7, second insulator 8, and slot insulator 9. In this disclosure, the term "blower side" refers to the side on which blower section 102 is located, and the term "anti-blower side" refers to the side opposite blower section 102.

[0015] As shown in FIG. 5, shaft 1 is formed in a cylindrical shape. Shaft 1 is formed, for example, by cutting a member made of carbon steel or other material with excellent mechanical strength and workability using a machine such as a lathe or milling machine. The outer periphery of cylindrical shaft 1 has region 1a where bearing 5 on the anti-blower side is attached, region 1b where commutator 4 is attached, region 1c where first insulator 7 is attached, region 1d where rotor core 2 is attached, region 1e where second insulator 8 is attached, and region 1f where blower-side bearing 6 is attached. Regions 1a, 1b, 1c, 1d, 1e, and 1f all have the same outer diameter.

[0016] The shaft 1 also has an area 1g at its blower-side end where the fan 16 of the blower section 102 is attached. Areas 1a, 1b, 1c, 1d, 1e, 1f, and 1g are arranged in this order from the end face 1z of the shaft 1 on the opposite side to the blower in the direction in which the shaft 1 extends, i.e., in the axial direction.

[0017] Fig. 7 is a cross-sectional view of rotor core 2 according to embodiment 1 as viewed from the front. As shown in Figs. 5, 6, and 7, in this embodiment, notches 1h are formed in the outer periphery of shaft 1. As shown in Fig. 5, notches 1h are formed in regions 1a, 1b, 1c, 1d, 1e, and 1f.

[0018] The notch 1h is formed, for example, in a U-shape. For example, a plurality of notches 1h may be provided. The plurality of notches 1h may be arranged symmetrically with respect to the radial center of the shaft 1. By arranging the plurality of notches 1h symmetrically, it is possible to balance the mass.

[0019] The rotor core 2 is formed, for example, by pressing and laminating multiple electromagnetic steel sheets formed by rolling silicon steel with excellent magnetic permeability. As shown in FIG. 7, the rotor core 2 is provided with multiple slots 19. A rotor coil 3 is wound in the slots 19 of the rotor core 2. Rotor teeth 21 are formed between the multiple slots 19. The shaft 1 is attached to the center of the rotor core 2.

[0020] Fig. 8 is a perspective view of the first insulator 7 of the first embodiment, seen from the pipe-shaped insulating portion 7a side. Fig. 9 is a perspective view of the first insulator 7 of the first embodiment, seen from the opposite side of the pipe-shaped insulating portion 7a. The configuration of the first insulator 7 will be described with reference to Figs. 8 and 9. Note that the second insulator 8 has the same configuration as the first insulator 7, so detailed illustrations and descriptions will be omitted.

[0021] The first insulator 7 is molded from a material with excellent insulating properties. As shown in Figures 8 and 9, the first insulator 7 is composed of a pipe-shaped insulating portion 7a and a plate-shaped insulating portion 7c. The pipe-shaped insulating portion 7a is a pipe-shaped portion with an inner diameter that matches the outer diameter of the shaft 1. The plate-shaped insulating portion 7c is a plate-shaped portion with an outer diameter that is smaller than the outer diameter of the rotor core 2. The plate-shaped insulating portion 7c has a notch 7b that has the same or approximately the same shape as the slot 19. The pipe-shaped insulating portion 7a is held concentric with the shaft 1. The opposite end face of the plate-shaped insulating portion 7c abuts against the end face of the rotor core 2.

[0022] The first insulator 7 and the second insulator 8 are arranged to sandwich the rotor core 2. The first insulator 7 abuts against one end face of the rotor core 2. The second insulator 8 abuts against the other end face of the rotor core 2.

[0023] The slot insulators 9 are components formed from, for example, a film or resin material with excellent insulating properties, in the same or substantially the same shape as the slots 19. The slot insulators 9 are disposed inside the slots 19 so as to abut against the rotor core 2.

[0024] A cylindrical commutator 4 is attached to the shaft 1 so as to be concentric with the shaft 1. The commutator 4 and the rotor coil 3 are electrically connected. Meanwhile, a pipe-shaped insulator 7a is disposed between the shaft 1 and the rotor coil 3, so that the shaft 1 and the rotor coil 3 are electrically insulated from each other. Similarly, a plate-shaped insulator 7c and a slot insulator 9 are disposed between the rotor core 2 and the rotor coil 3, so that the rotor core 2 and the rotor coil 3 are electrically insulated from each other.

[0025] The bearing 5 on the side opposite the blower, which is attached to the shaft 1, is inserted into a housing portion 13a of the frame 13. The bearing 6 on the blower side is inserted into a housing portion 15a formed in a bracket 15, which will be described later. In this way, the rotor 103 is housed and fixed within the frame 13.

[0026] Bracket 15 is a member that fixes rotor 103 together with frame 13. Bracket 15 is formed, for example, by pressing an aluminum alloy. Bracket 15 has a bridge portion 15b that spans the open side of frame 13, and a housing portion 15a whose diameter is smaller than the overall length of bridge portion 15b. An opening is formed at the tip of housing portion 15a, and shaft 1 of rotor 103 passes through this opening.

[0027] The stator 104 is composed of a stator core 10, a stator coil 11, and a winding frame 12. The stator core 10 is formed, for example, by pressing and laminating multiple electromagnetic steel sheets formed by rolling silicon steel, which has excellent magnetic permeability. The stator coil 11 is wound around the slots of the stator core 10 via the winding frame 12 made of an insulating material.

[0028] The stator 104 is disposed in the space inside the frame 13 so as to surround the rotor core 2 of the rotor 103. The stator 104 is used to generate a magnetic force that acts on the rotor 103.

[0029] A pair of brush units 105 are attached to the frame 13 by, for example, screws. The brush units 105 are attached symmetrically with respect to the commutator 4.

[0030] FIG. 10 is a cross-sectional view showing the air flow when electric blower 100 of the first embodiment is viewed from the side. The components that make up rotor 103 are housed in frame 13. That is, shaft 1, commutator 4, rotor core 2, rotor coil 3, first insulator 7, and second insulator 8 are housed in frame 13. Blower unit 102 is attached to shaft 1 and blows external air into frame 13. As shown in FIGS. 2 and 10, blower unit 102 is made up of diffuser 17, fan 16, and fan cover 18.

[0031] The diffuser 17 is used to increase the pressure of the airflow generated by the fan 16, stabilize it, and efficiently send out the air. The diffuser 17 is formed, for example, by injection molding a resin material. An opening is formed in the center of the diffuser 17, and the housing portion 15a of the bracket 15 is inserted into this opening. The diffuser 17 is attached to the bracket 15, for example, by screws.

[0032] The fan 16 is attached to an area 1g provided on the outer periphery of the shaft 1 of the rotor 103 that passes through the diffuser 17. The fan cover 18 is a casing that forms an air passage when combined with the flange portion 13c of the frame 13. The fan cover 18 is attached so as to cover the fan 16. The fan cover 18 is formed, for example, by pressing an aluminum alloy.

[0033] As shown in Figure 10, fan cover 18 is formed with air intake port 102a through which electric blower 100 draws in outside air. Rotation of rotor 103 rotates fan 16, which draws air through air intake port 102a. The air drawn in through air intake port 102a is introduced into motor unit 101 by diffuser 17, where it cools rotor 103, stator 104, and brush unit 105, and is then discharged outside electric blower 100 through exhaust port 13d.

[0034] In this embodiment, the notch 1h formed in the shaft 1 creates gaps between the outer circumferential surface of the shaft 1 and the inner circumferential surface of the second insulator 8, between the outer circumferential surface of the shaft 1 and the inner circumferential surface of the rotor core 2, between the outer circumferential surface of the shaft 1 and the inner circumferential surface of the first insulator 7, and between the outer circumferential surface of the shaft 1 and the inner circumferential surface of the commutator 4. Air introduced near the blower-side bearing 6 of the rotor 103 passes through these gaps and near the brush unit 105 and is discharged to the outside of the electric blower 100 through the exhaust port 13d. This allows the rotor core 2, rotor coil 3, and commutator 4 to be sufficiently cooled and reduces heat generation. It also reduces heat generation in the brush unit 105.

[0035] For example, forming a through hole in shaft 1 to cool the inside of electric blower 100 requires complex processing, which increases manufacturing costs. With this embodiment, it is possible to sufficiently cool the inside of electric blower 100 while suppressing manufacturing costs without requiring complex processing.

[0036] Fig. 11 is a cross-sectional view showing a first modified example of electric blower 100 of embodiment 1. As shown in Fig. 11, in this modified example, notch 1h is formed in regions 1a, 1b, 1c, 1d, 1e, and 1f, and also extends to region 1g where fan 16 is attached. That is, in this modified example, notch 1h is formed so as to penetrate from end face 1z on the opposite side from the blower to fan 16.

[0037] In this modification, for example, when air intake 102a is sealed, even if fan 16 rotates, air flows in through opening 24 of frame 13 and then passes through notch 1h to be discharged to the center of blower section 102, as shown in Fig. 11, so the degree of vacuum inside electric blower 100 does not increase abnormally. This modification has the effect of preventing damage to fan 16 due to an increase in centrifugal force caused by an increase in the rotation speed of electric blower 100 due to an abnormal increase in the degree of vacuum.

[0038] Fig. 12 is a perspective view of the first insulator 7 in a second modified example of the first embodiment, seen from the opposite side of the pipe-shaped insulating portion 7a. Fig. 13 is a front view of the first insulator 7 in the second modified example of the first embodiment, seen from the opposite side of the pipe-shaped insulating portion 7a. Fig. 14 is a cross-sectional view of the rotor 103 in the second modified example of the first embodiment, seen from the side. Note that the second insulator 8 has the same configuration as the first insulator 7, so detailed illustration and description will be omitted.

[0039] In the second modification, a concave circular step 7d and radial steps 7e are formed on the end face of the plate-shaped insulating part 7c opposite the pipe-shaped insulating part 7a. The radial steps 7e are formed radially from the outer periphery of the circular step 7d. The depth of the steps 7d is, for example, 0.5 mm or more.

[0040] Circular step 7d is formed in a circular shape concentric with pipe-shaped insulating portion 7a. Circular step 7d is formed in a circular shape with a diameter smaller than the outer diameter φA of an imaginary circle passing through the deepest point 7f of notch 7b, which has the same or approximately the same shape as slot 19. Radial step 7e is formed in a concave shape radially from the center of pipe-shaped insulating portion 7a, with a width smaller than the width of rotor tooth 21.

[0041] As shown in Figure 14, air introduced into the blower side of the rotor 103 is guided to the notch 1h provided in the shaft 1 and then guided to the inside of the inner circumferential surface of the pipe-shaped insulating section 8a of the second insulator 8. Part of the air guided to the inside of the inner circumferential surface of the pipe-shaped insulating section 8a is guided to the inside of the inner circumferential surface of the rotor core 2. Another part is guided to the gap between the rotor core 2 and the concave circular step 8d of the second insulator 8, passes between the radial step 8e of the second insulator 8 and the end face of the rotor core 2, and is sent out of the rotor 103.

[0042] Furthermore, the air guided toward the inside of the inner circumferential surface of the rotor core 2 is similarly guided into the gap between the concave circular step 7d of the first insulator 7 and the rotor core 2, passes between the radial step 7e and the end face of the rotor core 2, and is sent out to the outside of the rotor 103. In the second modified example, air is sent to the end face of the rotor core 2, including the rotor teeth 21, making it possible to more efficiently suppress heat generation from the rotor core 2 and the rotor coil 3.

[0043] FIG. 15 is a diagram showing the distribution of magnetic field lines 22 in a cross section of a rotor core of a conventional electric blower, which is a comparative example. In this comparative example, a through hole 23 is formed in the rotor shaft. FIG. 16 is a diagram showing the distribution of magnetic field lines 22 in a cross section of a rotor core 2 in a third modified example of the first embodiment. For ease of explanation, FIGS. 15 and 16 will be described assuming that the rotor core has a reduced number of slots. Furthermore, the magnetic field lines 22 will be described while ignoring distortion due to armature reaction.

[0044] When a voltage is applied and a current flows through the stator coil 11, a magnetic field is generated in the stator core 10 due to electromagnetic induction. The strength of this magnetic field is expressed as the number of magnetic field lines 22. The magnetic field lines 22 generated in the stator core 10 circle the stator coil 11 and form a magnetic circuit.

[0045] As described above, the stator core 10 and the rotor core 2 are formed using, for example, electromagnetic steel sheets produced by rolling silicon steel, which has excellent magnetic permeability. The magnetic permeability of electromagnetic steel sheets is generally 5,000 to 10,000 times higher than that of air. Electromagnetic steel sheets have the property of allowing magnetic lines of force to pass easily. Furthermore, for example, carbon steel, which has excellent mechanical strength and workability, is used for the shaft 1, and its magnetic permeability is approximately 500 to 1,000 times higher than that of air. Although carbon steel does not allow magnetic lines of force to pass easily compared to electromagnetic steel sheets, it still functions as part of the magnetic path.

[0046] The magnetic field lines 22 flow more in areas with higher magnetic permeability and larger cross-sectional areas of the magnetic path. In the conventional motor shown in Figure 15, the distribution of the magnetic field lines 22 during operation is dense between the rotor teeth and the shaft, but sparse on the shaft due to the presence of the through-holes 23. This reduces the amount of magnetic field lines 22, which may lead to a decrease in magnetic force.

[0047] Electrical steel sheets are rolled during the manufacturing process, resulting in anisotropy, whereby magnetic properties vary depending on the direction. The direction parallel to the rolling direction of the electrical steel sheets allows magnetic field lines 22 to pass most easily. The direction perpendicular to the rolling direction allows magnetic field lines 22 to pass least easily. When the rotor rotates, the more magnetic field lines 22 there are, the greater the torque obtained, so the torque fluctuates depending on the ease with which the magnetic field lines pass.

[0048] In a third modification of the present embodiment, as shown in FIG. 16 , the notches 1h on the outer periphery of the shaft 1 are arranged on a line that is parallel to the rolling direction of the electromagnetic steel sheets and passes through the center of the shaft 1. As a result, at the moment when the rolling direction of the electromagnetic steel sheets and the magnetic field lines 22 become perpendicular to each other during rotation of the rotor 103, the notches 1h are located at both ends of the shaft 1 with respect to the direction of the magnetic field lines 22, and the magnetic field lines 22 can pass through the center of the shaft 1. According to the third modification, the influence on the reduction of magnetic flux can be suppressed. In the third modification, the fluctuation in the amount of the magnetic field lines 22 in relation to the rolling direction of the electromagnetic steel sheets is reduced, resulting in an effect of suppressing torque fluctuations of the rotor 103. [Explanation of symbols]

[0049] 1 shaft 1a area 1b area 1c area 1d area 1e area 1f area 1g area 1h notch 1z end face 2 rotor core 3 rotor coil 4 commutator 5. Bearings 6 Bearings 7 First Insulator 7a Pipe insulation 7b Notch 7c Plate-shaped insulating part 7d Step part 7e Step part 7f deepest point 8 Second Insulator 8a Pipe insulation 8d Step part 8e Step 9 Slot Insulator 10 stator core 11 Stator coil 12 Reel frame 13 frames 13a Housing part 13b Torso 13c Flange 13d Exhaust port 15 Bracket 15a Housing part 15b Bridge section 16 Fans 17 Diffuser 18 Fan cover 19 slots 21 rotor teeth 22 Magnetic field lines 23 Through hole 24 Opening 100 electric blower 101 Motor section 102 Blower section 102a Air intake 103 rotor 104 Stator 105 Brush unit

Claims

1. A shaft, a commutator attached to the shaft; a rotor core attached to the shaft; a rotor coil wound in the slot of the rotor core; a first insulator abutting against one side end surface of the rotor core; a second insulator abutting against the other end surface of the rotor core; a blower unit attached to the shaft and configured to blow outside air into a frame that accommodates the shaft, the rotor core, the rotor coil, the first insulator, and the second insulator; an exhaust port for discharging the air sent out by the blower unit; Equipped with A notch is formed on the outer periphery of the shaft, the notch is formed over an area where a bearing on the opposite side to the blower is attached, an area where the commutator is attached, an area where the first insulator is attached, an area where the rotor core is attached, and an area where the second insulator is attached.

2. 2. The electric blower according to claim 1, wherein the notch is further formed over an area where a bearing on the blower side is attached and an area where a fan of the blower section is attached.

3. 3. The electric blower according to claim 1, wherein the plurality of notches are formed symmetrically with respect to the center of the shaft in the light direction.

4. the first insulator is composed of a pipe-shaped insulating portion configured to be concentric with the shaft and a plate-shaped insulating portion abutting against an end surface of the rotor core, 3. The electric blower according to claim 1, wherein a concave circular step portion and a radial step portion are formed on an end surface of the plate-shaped insulating portion opposite to the pipe-shaped insulating portion.

5. 3. The electric blower according to claim 1, wherein the notch is arranged on a line that is parallel to the rolling direction of the electromagnetic steel sheet that forms the rotor core and that passes through the center of the shaft.

Images