Axial gap type motor, blower device, and air conditioner

Abstract

To solve the problem that noise having a peak of a sound pressure level occurs at a frequency near a specific frequency of an air gap between a rotor and a stator due to slight vibration in an axial direction of the rotor during the drive of an axial gap type motor.SOLUTION: A motor 40 comprises rotors 50, 60 and a stator 70. The rotors 50, 60 are in disk shapes. The stator 70 faces the rotors 50, 60 via air gaps G1, G2 in axial directions of the rotors 50, 60. The stator 70 comprises a plurality of stator cores 71, and coils 72 wound around the respective stator cores 71. The plurality of stator cores 71 are annularly arranged when viewed from the axial directions of the rotors 50, 60. The rotors 50, 60 comprise a plurality of through holes 54, 64 penetrating in the axial directions of the rotors 50, 60. The plurality of through holes 54, 64 are provided on an inner side in the radial directions of the rotors 50, 60 than the coils 72 when viewed from the axial directions of the rotors 50, 60.SELECTED DRAWING: Figure 11

Description

[Technical field]

[0001] The present disclosure relates to an axial gap motor, a blower device, and an air conditioner. [Background technology]

[0002] 2. Description of the Related Art As disclosed in Patent Document 1 (JP Patent Publication No. 2006-353078), there is known an axial gap motor that includes a rotor and a stator that faces the rotor in the axial direction of the rotor via an air gap. Summary of the Invention [Problem to be solved by the invention]

[0003] In an axial gap motor, the space between the rotor and stator (air gap) has a natural frequency. Therefore, when the motor is running, minute axial vibrations of the rotor can cause abnormal noise with a peak sound pressure level at a frequency near the natural frequency of the air gap. [Means for solving the problem]

[0004] An axial gap type motor according to a first aspect includes a rotor and a stator. The rotor is disk-shaped. The stator faces the rotor via an air gap in the axial direction of the rotor. The stator has a plurality of stator cores and coils wound around each of the stator cores. The plurality of stator cores are arranged in an annular shape when viewed from the axial direction of the rotor. The rotor has a plurality of through holes that penetrate the rotor in the axial direction. The plurality of through holes are provided radially inward of the rotor than the coils when viewed from the axial direction of the rotor.

[0005] In the axial gap motor of the first aspect, a through hole is provided in the center of the rotor to make the natural frequency of the air gap higher than a predetermined frequency, thereby reducing the sound pressure level at frequencies near the natural frequency when no through hole is provided, thereby reducing abnormal noise generated by the motor.

[0006] The axial gap motor of a second aspect is the axial gap motor of the first aspect, wherein the through holes are provided in a circular first region centered on the rotation axis of the rotor when viewed from the axial direction of the rotor, and the radius of the first region is 40% or less of the radius of the rotor.

[0007] An axial gap motor according to a third aspect is an axial gap motor according to the first or second aspect, wherein a first ratio, which is a ratio between a total area of ​​the plurality of through holes and an opening area of ​​an outer edge portion of the air gap, is 3% or more.

[0008] An axial gap motor according to a fourth aspect is the axial gap motor according to the third aspect, wherein the first ratio is 10% or more.

[0009] An axial gap motor according to a fifth aspect is the axial gap motor according to the third aspect, wherein the first ratio is 20% or more.

[0010] An axial gap motor according to a sixth aspect is the axial gap motor according to any one of the third to fifth aspects, in which the first ratio is 40% or less.

[0011] An axial gap motor of a seventh aspect is an axial gap motor of any one of the first to sixth aspects, wherein the plurality of through holes are arranged along the circumference of a first circle so that the centers of the through holes are located on the circumference of the first circle centered on the rotational axis of the rotor when viewed from the axial direction of the rotor.

[0012] An axial gap motor according to an eighth aspect is the axial gap motor according to any one of the first to seventh aspects, and includes a pair of rotors and a stator sandwiched between the pair of rotors.

[0013] A blower device according to a ninth aspect includes the axial gap motor according to any one of the first to eighth aspects, and a fan driven by the axial gap motor.

[0014] An air conditioner according to a tenth aspect includes the blower according to the ninth aspect. [Brief description of the drawings]

[0015] [Figure 1] 1 is an external perspective view of a blower device 100 according to a first embodiment. [Diagram 2] 2 is an external perspective view of a first fan 20, a second fan 30, and a motor 40 according to the first embodiment. FIG. [Diagram 3] FIG. 2 is a side view of the first fan 20, the second fan 30, and the motor 40 of the first embodiment. [Figure 4] FIG. 2 is an exploded perspective view of a first fan 20, a second fan 30, and a motor 40 according to the first embodiment. [Diagram 5] FIG. 2 is a plan view of a first rotor 50 according to the first embodiment. [Figure 6] FIG. 2 is an external perspective view of a first rotor 50 according to the first embodiment. [Figure 7] FIG. 2 is a plan view of the second rotor 60 according to the first embodiment. [Figure 8] FIG. 2 is an external perspective view of a second rotor 60 according to the first embodiment. [Figure 9] FIG. 2 is a plan view of a stator 70 according to the first embodiment. [Figure 10] FIG. 2 is an external perspective view of a stator 70 according to the first embodiment. [Figure 11] 2 is a cross-sectional view of a motor 40 according to the first embodiment. FIG. [Figure 12] 10 is a diagram for explaining a standing wave having a natural frequency of the first air gap G1, and shows a standing wave in the case where the first rotor 50 does not have a through hole 54. [Figure 13] 10 is a diagram for explaining a standing wave having a natural frequency of the first air gap G1. FIG 11 is a diagram showing a standing wave when the first rotor 50 has a through hole 54. [Figure 14] 1 is an example of measurement data showing the relationship between the frequency of the micro-vibration applied to the first rotor 50 and the sound pressure level. [Figure 15]1 is an example of measurement data of noise generated when the motor 40 is driven. [Figure 16] 1 is an example of measurement data showing the relationship between the number of through holes 54, 64 and the sound pressure level. [Figure 17] FIG. 11 is a plan view of a first rotor 50 according to a second embodiment. [Figure 18] FIG. 11 is a plan view of a first rotor 50 according to a third embodiment. [Figure 19] FIG. 11 is a plan view of a first rotor 50 according to a fourth embodiment. [Figure 20] FIG. 13 is a plan view of the first rotor 50 of the modified example D-1. [Figure 21] FIG. 13 is a plan view of the first rotor 50 of the modified example D-2. [Figure 22] FIG. 13 is a plan view of the first rotor 50 of a modified example D-3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] -First embodiment- (1) Overall configuration of the blower device 100 The blower 100 of the first embodiment of the present disclosure is used in, for example, an air conditioner. In this case, the air conditioner includes an indoor unit equipped with the blower 100, and an outdoor unit connected to the indoor unit via a refrigerant circuit. The refrigerant circuit includes, for example, a compressor, a four-way switching valve, an outdoor heat exchanger, an electric expansion valve, an indoor heat exchanger, and an accumulator.

[0017] 1, the blower 100 includes a housing 10, a first fan 20, a second fan 30, and a motor 40. The first fan 20 and the second fan 30 are centrifugal fans such as sirocco fans.

[0018] The housing 10 has a cylindrical portion 10a that houses the first fan 20 and the second fan 30, and a blowing portion 10b that protrudes from the cylindrical portion 10a. In the longitudinal direction of the cylindrical portion 10a, a flange 13 having a first suction port 11 is provided at one end of the cylindrical portion 10a, and a flange (not shown) having a second suction port 12 is provided at the other end of the cylindrical portion 10a. Bell mouths 14 are provided at the first suction port 11 and the second suction port 12. In FIG. 1, only the bell mouth 14 on the first suction port 11 side is shown. A ring-shaped motor fixing portion 10c is provided along the circumferential direction on the outer periphery of the central portion in the longitudinal direction of the cylindrical portion 10a. The blowing portion 10b has a quadrangular pyramid shape that gradually widens toward the outside along the circumferential direction of the cylindrical portion 10a. An air outlet 15 is provided at the outer end of the blowing portion 10b.

[0019] 2 to 4, the first fan 20 has a disk-shaped end plate 21, a plurality of blades 22, and an annular member 23. The plurality of blades 22 are connected to one surface of the end plate 21 and are arranged at intervals along the circumferential direction of the end plate 21. The annular member 23 is connected to ends of the plurality of blades 22 on the side opposite to the side to which the end plate 21 is connected.

[0020] 2 to 4, the second fan 30 has a disk-shaped end plate 31, a plurality of blades 32, and an annular member 33. The plurality of blades 32 are connected to one surface of the end plate 31 and are arranged at intervals along the circumferential direction of the end plate 31. The annular member 33 is connected to ends of the plurality of blades 32 on the side opposite to the side to which the end plate 31 is connected.

[0021] The motor 40 is an axial gap type motor. As shown in Fig. 4, the motor 40 has a disk-shaped first rotor 50, a disk-shaped second rotor 60, and a disk-shaped stator 70. Hereinafter, the direction along the rotation axes of the first rotor 50 and the second rotor 60 will be referred to as the "axial direction". The stator 70 is disposed between the first rotor 50 and the second rotor 60 in the axial direction.

[0022] (2) Detailed configuration of motor 40 The first rotor 50 is disposed opposite the end plate 21 of the first fan 20. As shown in FIG 3, the end plate 21 of the first fan 20 is disposed in a non-contact state with the first rotor 50 of the motor 40.

[0023] As shown in FIG. 5 and FIG. 6, the first rotor 50 has a boss portion 52 and a magnet member 53 provided on the outer periphery of the boss portion 52. The boss portion 52 is molded from metal. The boss portion 52 has a cylindrical shape. The boss portion 52 has a circular hole 52a in the center. The magnet member 53 is molded from a plastic magnet. The magnet member 53 has a disk shape. When molding the magnet member 53, the boss portion 52 is attached to a mold as an insert part, so that the boss portion 52 and the magnet member 53 are molded integrally. The magnet member 53 has a protruding portion 53a that does not act as a magnet, and a magnet portion 53b that acts as a magnet. The protruding portion 53a is a portion of the magnet member 53 that protrudes in the axial direction on the side of the first fan 20 and is recessed on the side of the stator 70. The protruding portion 53a has a circular shape when viewed from the axial direction. The boss portion 52 is located at the center of the protruding portion 53a when viewed from the axial direction. The magnet portion 53b is located around the protruding portion 53a when viewed from the axial direction. In the magnet portion 53b, as shown in FIG. 5, the south poles and the north poles are alternately arranged in the circumferential direction of the magnet member 53.

[0024] The second rotor 60 is disposed opposite the end plate 31 of the second fan 30. As shown in FIG 3, the end plate 31 of the second fan 30 is disposed in a non-contact state with the second rotor 60 of the motor 40.

[0025] As shown in FIG. 7 and FIG. 8, the second rotor 60 has a boss portion 62 and a magnet member 63 provided on the outer periphery of the boss portion 62. The boss portion 62 is molded from metal. The boss portion 62 has a cylindrical shape. The boss portion 62 has a circular hole 62a in the center. The magnet member 63 is molded from a plastic magnet. The magnet member 63 has a disk shape. When molding the magnet member 63, the boss portion 62 is attached to a mold as an insert part, so that the boss portion 62 and the magnet member 63 are molded integrally. The magnet member 63 has a protruding portion 63a that does not act as a magnet and a magnet portion 63b that acts as a magnet. The protruding portion 63a is a portion of the magnet member 63 that protrudes in the axial direction on the second fan 30 side and is recessed on the stator 70 side. The protruding portion 63a has a circular shape when viewed from the axial direction. The boss portion 62 is located at the center of the protruding portion 63a when viewed from the axial direction. The magnet portion 63b is located around the protruding portion 63a when viewed from the axial direction. In the magnet portion 63b, the south poles and the north poles are alternately arranged in the circumferential direction of the magnet member 63, as shown in FIG.

[0026] As shown in Figures 9 to 11, the stator 70 has a plurality of stator cores 71, a plurality of coils 72, a shaft 73, a molded portion 74, an insulator 75, a first bearing 76, a second bearing 77, and a bearing housing 78.

[0027] When viewed in the axial direction, the multiple stator cores 71 are arranged in an annular shape at intervals along the circumferential direction of the stator 70. Each coil 72 is formed by winding a winding around each stator core 71. An insulator 75 insulates the stator core 71 from the coils 72.

[0028] The shaft 73 extends along the axial direction through the circular hole 52a of the first rotor 50 toward the first fan 20. The shaft 73 extends along the axial direction through the circular hole 62a of the second rotor 60 toward the second fan 30. On the first fan 20 side, the shaft 73 is fixed to the inner circumferential surface of the boss portion 52 of the first rotor 50 and the end plate 21 of the first fan 20. On the second fan 30 side, the shaft 73 is fixed to the inner circumferential surface of the boss portion 62 of the second rotor 60 and the end plate 31 of the second fan 30. When the first rotor 50 and the second rotor 60 rotate around the rotation axis while the motor 40 is driven, the first fan 20 and the second fan 30 rotate around the rotation axis. As the first fan 20 and the second fan 30 rotate, air outside the housing 10 is sucked into the first suction port 11 and the second suction port 12 and discharged from the air outlet 15.

[0029] The molded portion 74 is a disk-shaped member formed by resin molding so as to surround the stator core 71 and the coils 72. The molded portion 74 has an outer edge portion 74a that protrudes from a side surface of the molded portion 74. The outer edge portion 74a of the molded portion 74 is fixed by the motor fixing portion 10c of the housing 10.

[0030] The first bearing 76 is provided on the first rotor 50 side in the axial direction. The second bearing 77 is provided on the second rotor 60 side in the axial direction. The first bearing 76 and the second bearing 77 rotatably support the shaft 73. The bearing housing 78 accommodates the first bearing 76 and the second bearing 77.

[0031] 11, the stator 70 faces the first rotor 50 in the axial direction via a first air gap G1. The stator 70 faces the second rotor 60 in the axial direction via a second air gap G2. The axial dimensions of the first air gap G1 and the second air gap G2 are, for example, 0.5 mm to 2 mm.

[0032] 3, the outer diameter of the stator 70 is larger than the outer diameter of the first rotor 50 and the outer diameter of the second rotor 60. As shown in FIG. 11, the outer diameter of the molded portion 74 excluding the outer edge portion 74a is approximately the same as the outer diameter of the first rotor 50 and the outer diameter of the second rotor 60.

[0033] 11, the center of the molded portion 74 of the stator 70 protrudes in the axial direction on the side of the first fan 20 in accordance with the shape of the magnet member 53 of the first rotor 50. In addition, the center of the molded portion 74 of the stator 70 protrudes in the axial direction on the side of the second fan 30 in accordance with the shape of the magnet member 63 of the second rotor 60.

[0034] (3) Detailed configuration of the first rotor 50 and the second rotor 60 The first rotor 50 has a plurality of through holes 54 penetrating in the axial direction. The plurality of through holes 54 are provided in the protruding portion 53a of the magnet member 53. As shown in Fig. 11, the plurality of through holes 54 are provided radially inward of the first rotor 50 relative to the coils 72 when viewed in the axial direction. The through holes 54 communicate the space between the first rotor 50 and the end plate 21 with the first air gap G1.

[0035] 5, the first rotor 50 has ten through holes 54 arranged along the circumference of a first circle C1 centered on the rotation axis of the first rotor 50 when viewed in the axial direction. These through holes 54 have a circular shape when viewed in the axial direction and have the same size (diameter). The ten through holes 54 are arranged at equal intervals along the circumferential direction of the first circle C1. The diameter of the through holes 54 is, for example, 2.5 mm.

[0036] The through holes 54 are provided in a first region R1 that is circular and centered on the rotation axis of the first rotor 50 when viewed in the axial direction. In Fig. 5, the first region R1 is substantially the same as the region occupied by the boss portion 52 and the protruding portion 53a of the first rotor 50. As shown in Fig. 11, the boss portion 52 and the protruding portion 53a are located radially inward of the first rotor 50 with respect to the coil 72.

[0037] The radius of the first region R1 is 40% or less of the radius of the first rotor 50. The radius of the first rotor 50 is the dimension from the rotation axis of the first rotor 50 to the outer edge of the first rotor 50 when the first rotor 50 is viewed in the axial direction. The radius of the first region R1 is substantially less than the dimension from the rotation axis of the first rotor 50 to the outer edge of the protruding portion 53a when the first rotor 50 is viewed in the axial direction.

[0038] The radius of the first region R1 may be 25% or less of the radius of the first rotor 50. The radius of the first region R1 may be 20% or less of the radius of the first rotor 50. The radius of the first region R1 may be 15% or less of the radius of the first rotor 50.

[0039] The through holes 54 are provided outside the boss portion 52 when viewed in the axial direction. Therefore, it is preferable that the radius of the first region R1 is 5% of the radius of the first rotor 50 or more, for example.

[0040] The second rotor 60 has a plurality of through holes 64 penetrating in the axial direction. The plurality of through holes 64 are provided in the protruding portion 63a of the magnet member 63. As shown in Fig. 11, the plurality of through holes 64 are provided radially inward of the second rotor 60 relative to the coils 72 when viewed in the axial direction. The through holes 64 communicate the space between the second rotor 60 and the end plate 31 with the second air gap G2.

[0041] 7, the second rotor 60 has ten through holes 64 arranged along the circumference of a second circle C2 centered on the rotation axis of the second rotor 60 when viewed from the axial direction. These through holes 64 have a circular shape when viewed from the axial direction and have the same size (diameter). The ten through holes 64 are arranged at equal intervals along the circumferential direction of the second circle C2. The diameter of the through holes 64 is, for example, 2.5 mm.

[0042] The through holes 64 are provided in a circular second region R2 centered on the rotation axis of the second rotor 60 when viewed in the axial direction. In Fig. 7, the second region R2 is substantially the same as the region occupied by the boss portion 62 and the protruding portion 63a of the second rotor 60. As shown in Fig. 11, the boss portion 62 and the protruding portion 63a are located radially inward of the second rotor 60 relative to the coil 72.

[0043] The radius of the second region R2 is 40% or less of the radius of the second rotor 60. The radius of the second rotor 60 is the dimension from the rotation axis of the second rotor 60 to the outer edge of the second rotor 60 when the second rotor 60 is viewed in the axial direction. The radius of the second region R2 is substantially less than the dimension from the rotation axis of the second rotor 60 to the outer edge of the protruding portion 63a when the second rotor 60 is viewed in the axial direction.

[0044] The radius of the second region R2 may be 25% or less of the radius of the second rotor 60. The radius of the second region R2 may be 20% or less of the radius of the second rotor 60. The radius of the second region R2 may be 15% or less of the radius of the second rotor 60.

[0045] The through holes 64 are provided outside the boss portion 62 when viewed in the axial direction. Therefore, it is preferable that the radius of the second region R2 is 5% of the radius of the second rotor 60 or more, for example.

[0046] A first ratio, which is a ratio between the total area of ​​the plurality of through holes 54 of the first rotor 50 and the opening area of ​​the outer edge portion of the first air gap G1, is 3% or more. The first ratio means a ratio of the total area of ​​the plurality of through holes 54 to the opening area of ​​the outer edge portion of the first air gap G1. The total area of ​​the plurality of through holes 54 is the sum of the areas occupied by the through holes 54 when the first rotor 50 is viewed from the axial direction. The opening area is the area occupied by the first air gap G1 when the first air gap G1 is viewed from the horizontal direction. The opening area is calculated by multiplying the axial dimension of the first air gap G1 at the outer edge of the first rotor 50 by the length of the outer edge of the first rotor 50. The length of the outer edge of the first rotor 50 is calculated by multiplying the diameter of the first rotor 50 when viewed from the axial direction by pi.

[0047] The first ratio may be 10% or more. The first ratio may be 20% or more. The first ratio is preferably 40% or less.

[0048] A second ratio, which is a ratio between the total area of ​​the plurality of through holes 64 of the second rotor 60 and the opening area of ​​the outer edge portion of the second air gap G2, is 3% or more. The total area of ​​the plurality of through holes 64 is the sum of the areas occupied by the through holes 64 when the second rotor 60 is viewed in the axial direction. The opening area is the area occupied by the second air gap G2 when the second air gap G2 is viewed in the horizontal direction. The opening area is calculated by multiplying the axial dimension of the second air gap G2 at the outer edge of the second rotor 60 by the length of the outer edge of the second rotor 60. The length of the outer edge of the second rotor 60 is calculated by multiplying the diameter of the second rotor 60 when viewed in the axial direction by pi.

[0049] The second ratio may be 10% or more. The second ratio may be 20% or more. The second ratio is preferably 40% or less.

[0050] (4) Features (4-1) The axial gap motor 40 has a first air gap G1 between the first rotor 50 and the stator 70, and a second air gap G2 between the second rotor 60 and the stator 70. The air gaps G1 and G2 have natural frequencies. Therefore, while the motor 40 is running, minute axial vibrations of the rotors 50 and 60 may cause abnormal noise having a peak in sound pressure level at a frequency near the natural frequency of the air gaps G1 and G2.

[0051] In Figures 12 and 13, a standing wave is shown with the natural frequency of the first air gap G1. The standing wave represents a radial vibration of the air in the first air gap G1. When the air in the first air gap G1 is displaced radially outward, the amplitude of the standing wave is positive. When the air in the first air gap G1 is displaced radially inward, the amplitude of the standing wave is negative.

[0052] The first wave W1 shown in Fig. 12 represents a standing wave when the first rotor 50 does not have a through hole 54. The second wave W2 shown in Fig. 13 represents a standing wave when the first rotor 50 has a through hole 54. In Figs. 12 and 13, the standing wave shown by the dotted line is out of phase with the standing wave shown by the solid line by 180°.

[0053] When the first rotor 50 does not have the through hole 54, the open ends of the first air gap G1 (portions communicating with the external space of the motor 40) are only the two ends 55 of the first air gap G1. Therefore, as shown in FIG. 12, the antinodes (positions where the amplitude is maximum) of the first wave W1 are located only at the two ends 55 of the first air gap G1 in the radial direction of the first rotor 50. On the other hand, when the first rotor 50 has the through hole 54, the open ends of the first air gap G1 are the two ends 55 of the first air gap G1 and the through hole 54. Therefore, as shown in FIG. 13, the antinodes of the second wave W2 are located at the two ends 55 of the first air gap G1 and in the center where the through hole 54 is located. Therefore, the natural frequency of the second wave W2 is about twice the natural frequency of the first wave W1. In this way, the natural frequency of the first air gap G1 can be changed by providing the through holes 54 near the nodes (positions where the amplitude is zero) of the first wave W1 in the radial direction of the first rotor 50. The nodes of the first wave W1 are located at the center of the first air gap G1 in the radial direction of the first rotor 50.

[0054] FIG. 14 shows measurement data of the sound pressure level of abnormal noise generated when the first rotor 50 is subjected to micro-vibration by passing a micro-current through the coil 72 while changing the frequency using a signal generator. The horizontal axis of FIG. 14 represents the frequency of the micro-vibration of the first rotor 50. The vertical axis of FIG. 14 represents the sound pressure level of abnormal noise. The first measurement data represents the measurement data when the first rotor 50 does not have the through-hole 54. The second measurement data represents the measurement data when the first rotor 50 has the through-hole 54. From the first measurement data, the natural frequency of the first wave W1 shown in FIG. 12 is about 1150 Hz. From the second measurement data, the natural frequency of the second wave W2 shown in FIG. 13 is about 2050 Hz. Therefore, as described above, it was observed that the natural frequency of the first air gap G1 is about doubled by providing the through-hole 54 in the first rotor 50. It was also observed that the sound pressure level at the natural frequency of 1150 Hz when the first rotor 50 has the through holes 54 is lower than the sound pressure level at the natural frequency of 2050 Hz when the first rotor 50 does not have the through holes 54.

[0055] Therefore, in the axial gap motor 40, by providing a plurality of through holes 54 in the center of the first rotor 50 to make the natural frequency of the first air gap G1 higher than a predetermined frequency, abnormal noise having a peak sound pressure level at a frequency near the natural frequency of the first air gap G1 is reduced. Similarly, by providing a plurality of through holes 64 in the center of the second rotor 60 to make the natural frequency of the second air gap G2 higher than a predetermined frequency, abnormal noise having a peak sound pressure level at a frequency near the natural frequency of the second air gap G2 is reduced.

[0056] Fig. 15 shows an example of measurement data of noise generated when the motor 40 is driven. The third measurement data represents measurement data when the rotors 50, 60 do not have the through holes 54, 64. The fourth measurement data represents measurement data when the rotors 50, 60 have the through holes 54, 64. As shown in Fig. 15, it was observed that by providing the rotors 50, 60 with the through holes 54, 64, the values ​​of multiple peaks of the sound pressure level at a frequency around 1150 Hz are reduced.

[0057] Therefore, in the axial gap type motor 40, by providing the through holes 54, 64 in the rotors 50, 60, the abnormal noise generated by the motor 40 is reduced.

[0058] (4-2) By forming the open ends of the air gaps G1, G2 in the center of the rotor 50, 0, the natural frequency of the air gaps G1, G2 becomes higher than a predetermined frequency, and the sound pressure level at frequencies near the natural frequency decreases. Therefore, the degree of reduction in the sound pressure level at frequencies near the natural frequency changes depending on the number, shape, and position of the through holes 54, 64 that are the open ends of the air gaps G1, G2.

[0059] FIG. 16 shows measurement data representing the relationship between the number of through holes 54 of the first rotor 50 and the sound pressure level of the generated abnormal sound. The horizontal axis of FIG. 16 represents the number of through holes 54. The vertical axis of FIG. 16 represents the sound pressure level at 1100 Hz. 1100 Hz is the frequency at which the sound pressure level of the abnormal sound generated when the first rotor 50 does not have the through holes 54 is maximum. The horizontal axis of the graph in FIG. 16 shows the correspondence relationship between the number of through holes 54 and the first ratio. Since all the through holes 54 have the same dimensions, the first ratio is proportional to the number of the through holes 54. For example, when the number of the through holes 54 is 60, the first ratio is 40%, and when the number of the through holes 54 is 30, the first ratio is 20%. The range of the first ratio of the measurement data is 0% to 40%. 16 shows measurement data when the number of through holes 54 in the first rotor 50 is 0, 5, 10, 20, 30, and 60. As shown in FIG. 16, when the number of through holes 54 is 0, 5, 10, 20, 30, and 60, the first ratio is 0%, 3.3%, 6.7%, 13%, 20%, and 40%, respectively. The number, shape, and position of the through holes 64 in the second rotor 60 are the same as the number, shape, and position of the through holes 54 in the first rotor 50. Therefore, the second ratio is the same as the first ratio.

[0060] As shown in FIG. 16, it was observed that the sound pressure level decreased as the first ratio, which is the ratio of the total area of ​​the through holes 54 to the opening area of ​​the outer edge of the first air gap G1, increased. As the first ratio increased from 0% to 20%, a significant decrease in the sound pressure level was observed. Specifically, it was confirmed that when the first ratio was 3.3%, the sound pressure level was reduced by about 10 dB compared to when the first ratio was 0%. It was confirmed that when the first ratio was 20%, the sound pressure level was reduced by about 20 dB compared to when the first ratio was 0%. It was also observed that as the first ratio increased from 20% to 40%, the sound pressure level did not decrease at all.

[0061] Furthermore, if the first ratio exceeds 40%, the rigidity of the first rotor 50 decreases, and there is a risk that the axial vibration of the first rotor 50 will increase. Therefore, in order to ensure the rigidity of the first rotor 50, it is preferable that the first ratio is as small as possible. On the other hand, in order to reduce the sound pressure level, it is preferable that the first ratio is as large as possible. As shown in Fig. 16, from the viewpoints of the rigidity of the first rotor 50 and the reduction in the sound pressure level, the first ratio is preferably 3.3% to 20%, more preferably 6.7% to 20%, and even more preferably 13% to 20%.

[0062] Similarly, in order to ensure the rigidity of the second rotor 60, it is preferable that the second ratio is as small as possible. On the other hand, in order to reduce the sound pressure level, it is preferable that the second ratio is as large as possible. Therefore, like the first ratio, the second ratio is preferably 3.3% to 20%, more preferably 6.7% to 20%, and further preferably 13% to 20%.

[0063] Therefore, in an axial gap type motor 40, by appropriately setting the first ratio and the second ratio and providing through holes 54, 64 in the rotors 50, 60, it is possible to effectively reduce abnormal noise generated by the motor 40 while ensuring the rigidity of the rotors 50, 60.

[0064] -Second embodiment- The blower device 100 of the second embodiment has a basic configuration and operation in common with the blower device 100 of the first embodiment. The difference between the second embodiment and the first embodiment is the number and positions of the through holes 54 of the first rotor 50 and the through holes 64 of the second rotor 60.

[0065] In this embodiment, the first rotor 50 has 60 through holes 54. When viewed from the axial direction, these through holes 54 have a circular shape and the same size (diameter). As shown in Fig. 17, 20 through hole groups 54g, each of which is made up of three through holes 54 arranged along the radial direction of the first rotor 50, are arranged along the circumferential direction of the first rotor 50. In order to ensure the rigidity of the first rotor 50, the radial positions of two through hole groups 54g adjacent to each other in the circumferential direction are different by approximately the diameter of the through holes 54.

[0066] The multiple through holes 64 of the second rotor 60 are arranged at the same positions as the multiple through holes 54 of the first rotor 50 .

[0067] -Third embodiment- The blower device 100 of the third embodiment has a basic configuration and operation in common with the blower device 100 of the first embodiment. The difference between the third embodiment and the first embodiment is the number and positions of the through holes 54 of the first rotor 50 and the through holes 64 of the second rotor 60.

[0068] In this embodiment, the first rotor 50 has ten through holes 54. As shown in Fig. 18, when viewed from the axial direction, the ten through holes 54 are arranged along the circumference of a third circle C3 centered on the rotation axis of the first rotor 50. These through holes 54 have a circular shape when viewed from the axial direction.

[0069] The ten through holes 54 are composed of two types of through holes having different sizes. The ten through holes 54 are composed of five first through holes 54a and five second through holes 54b. The diameter of the second through holes 54b is larger than the diameter of the first through holes 54a. For example, the diameter of the second through holes 54b is 1.5 times the diameter of the first through holes 54a. The ten through holes 54 are arranged at equal intervals along the circumferential direction of the third circle C3. The ten through holes 54 are arranged so that the first through holes 54a and the second through holes 54b are alternately arranged along the circumferential direction of the third circle C3.

[0070] In this embodiment, two types of through holes 54 with different sizes are arranged alternately in the circumferential direction, so that the first ratio can be increased to reduce abnormal noise generated by the motor 40 while ensuring the rigidity of the first rotor 50.

[0071] The multiple through holes 64 of the second rotor 60 are arranged at the same positions as the multiple through holes 54 of the first rotor 50 .

[0072] -Fourth embodiment- The blower device 100 of the fourth embodiment has a basic configuration and operation in common with the blower device 100 of the first embodiment. The fourth embodiment differs from the first embodiment in the number, shape, and position of the through holes 54 of the first rotor 50 and the through holes 64 of the second rotor 60.

[0073] In this embodiment, the first rotor 50 has 20 through holes 54. As shown in Fig. 19, a total of 20 through holes 54 are arranged along the circumferences of a fourth circle C4 and a fifth circle C5 centered on the rotation axis of the first rotor 50 when viewed from the axial direction. These through holes 54 have a substantially rectangular shape extending along the circumferential direction of the fourth circle C4 and the fifth circle C5 when viewed from the axial direction. The diameter of the fifth circle C5 is larger than the diameter of the fourth circle C4.

[0074] The 20 through holes 54 are composed of two types of through holes having different sizes. The 20 through holes 54 are composed of 10 third through holes 54c and 10 fourth through holes 54d. The 10 third through holes 54c are arranged at equal intervals along the circumferential direction of the fourth circle C4. The centers of the third through holes 54c are located on the circumference of the fourth circle C4. The 10 fourth through holes 54d are arranged at equal intervals along the circumferential direction of the fifth circle C5. The centers of the fourth through holes 54d are located on the circumference of the fifth circle C5. The center of the through hole 54 is the intersection of a straight line that passes through the rotation axis of the first rotor 50 and divides the through hole 54 in the circumferential direction in two with the fourth circle C4 or the fifth circle C5 when viewed from the axial direction.

[0075] The dimension of the fourth through hole 54d in the circumferential direction of the fifth circle C5 is larger than the dimension of the third through hole 54c in the circumferential direction of the fourth circle C4. For example, the dimension of the fourth through hole 54d in the circumferential direction of the fifth circle C5 is twice the dimension of the third through hole 54c in the circumferential direction of the fourth circle C4.

[0076] In this embodiment, the through hole 54 has a generally rectangular shape extending along the circumferential direction of the fourth circle C4 and the fifth circle C5, so that the first ratio can be increased and abnormal noise generated by the motor 40 can be effectively reduced.

[0077] 19, when viewed from the axial direction, the center of the fourth through hole 54d is not located on a straight line connecting the rotation shaft of the first rotor 50 and the center of the third through hole 54c. Similarly, when viewed from the axial direction, the center of the third through hole 54c is not located on a straight line connecting the rotation shaft of the first rotor 50 and the center of the fourth through hole 54d. By arranging the through holes 54 in this manner, the rigidity of the first rotor 50 can be ensured.

[0078] The multiple through holes 64 of the second rotor 60 are arranged at the same positions as the multiple through holes 54 of the first rotor 50 .

[0079] --Variations-- (1) Variation A In the above embodiment, the motor 40 has a pair of the first rotor 50 and the second rotor 60 arranged on both axial sides of the stator 70. However, the motor 40 may have only the first rotor 50. In this case, the blower device 100 may have both the first fan 20 and the second fan 30, or may have only the first fan 20.

[0080] (2) Variation B In the above embodiment, the first fan 20 and the second fan 30 are sirocco fans. However, the above embodiment may be applied to a blower device including other types of fans.

[0081] (3) Variation C When a plurality of through holes 54, 64 are arranged side by side in the circumferential direction of the rotors 50, 60, it is preferable to arrange the through holes 54, 64 so that the area occupied by the through holes 54, 64 in the circumferential direction is as large as possible. In this case, the area of ​​the open ends of the air gaps G1, G2 located in the central parts of the rotors 50, 60 becomes large, and the natural frequency of the air gaps G1, G2 increases, which tends to reduce the sound pressure level.

[0082] Specifically, as shown in Fig. 5, when the plurality of through holes 54 are arranged along the circumference of the first circle C1 such that the centers of the through holes 54 are located on the circumference of the first circle C1, it is preferable that the third ratio is equal to or greater than a predetermined value. The third ratio is the ratio between the total length of the plurality of through holes 54 in the circumferential direction of the first circle C1 and the circumferential length of the first circle C1. The larger the area occupied by the through holes 54, 64 in the circumferential direction of the rotors 50, 60, the higher the third ratio. Therefore, the larger the third ratio, the lower the sound pressure level tends to be. The third ratio is preferably equal to or greater than 0.1, and more preferably equal to or greater than 0.2.

[0083] (4) Variation D 16 shows measurement data when the number of through holes 54 in the first rotor 50 is 0, 5, 10, 20, 30, and 60. When viewed from the axial direction, the shape of the through holes 54 is all circular. The dimensions of the through holes 54 are all the same.

[0084] 5 and 17 show the arrangement of the through holes 54 when the number of the through holes 54 is 10 and 60, respectively. Next, specific examples of the arrangement of the through holes 54 when the number of the through holes 54 is 5, 20, and 30 will be described.

[0085] (4-1) Modification D-1 20 shows an arrangement of the through holes 54 when the number of through holes 54 is five. The first rotor 50 has five through holes 54 arranged along the circumference of a sixth circle C6 centered on the rotation axis of the first rotor 50 when viewed from the axial direction. The five through holes 54 are arranged at equal intervals along the circumferential direction of the sixth circle C6.

[0086] (4-2) Modification D-2 FIG. 21 shows an arrangement of the through holes 54 when the number of the through holes 54 is 20. The first rotor 50 has a total of 20 through holes 54 arranged along the circumferences of a seventh circle C7 and an eighth circle C8 centered on the rotation axis of the first rotor 50 when viewed from the axial direction. The diameter of the eighth circle C8 is larger than the diameter of the seventh circle C7. The ten through holes 54 are arranged at equal intervals along the circumferential direction of the seventh circle C7. The ten through holes 54 are arranged at equal intervals along the circumferential direction of the eighth circle C8.

[0087] Furthermore, when viewed in the axial direction, the center of the through hole 54 on the eighth circle C8 is not located on a straight line connecting the rotation axis of the first rotor 50 and the center of the through hole 54 on the seventh circle C7. Similarly, when viewed in the axial direction, the center of the through hole 54 on the seventh circle C7 is not located on a straight line connecting the rotation axis of the first rotor 50 and the center of the through hole 54 on the eighth circle C8.

[0088] The 20 through holes 54 may be disposed at equal intervals along the circumferential direction of the seventh circle C7.

[0089] (4-3) Modification D-3 FIG. 22 shows an arrangement of the through holes 54 when the number of the through holes 54 is 30. The first rotor 50 has a total of 30 through holes 54 arranged along the circumferences of the ninth circle C9 and the tenth circle C10 centered on the rotation axis of the first rotor 50 when viewed from the axial direction. The diameter of the tenth circle C10 is larger than the diameter of the ninth circle C9. The fifteen through holes 54 are arranged at equal intervals along the circumferential direction of the ninth circle C9. The fifteen through holes 54 are arranged at equal intervals along the circumferential direction of the tenth circle C10.

[0090] Furthermore, when viewed in the axial direction, the center of the through hole 54 on the tenth circle C10 is not located on a straight line connecting the rotation axis of the first rotor 50 and the center of the through hole 54 on the ninth circle C9. Similarly, when viewed in the axial direction, the center of the through hole 54 on the ninth circle C9 is not located on a straight line connecting the rotation axis of the first rotor 50 and the center of the through hole 54 on the tenth circle C10.

[0091] The 30 through holes 54 may be disposed at equal intervals along the circumferential direction of the ninth circle C9.

[0092] In this modified example, the multiple through holes 64 of the second rotor 60 are arranged at the same positions as the multiple through holes 54 of the first rotor 50.

[0093] -Conclusion- Although the embodiments of the present disclosure have been described above, it will be understood that various changes in form and details can be made without departing from the spirit and scope of the present disclosure described in the claims. [Explanation of symbols]

[0094] 20: 1st Fan (Fan) 30: 2nd Fan (Fan) 40: Axial gap motor (motor) 50: First rotor (rotor) 54: Through hole 60: Second rotor (rotor) 64:Through hole 70: Stator 71: Stator core 72: Coil 100: Blower G1: First air gap (air gap) G2: Second air gap (air gap) R1: 1st area X: Axial direction of the rotor [Prior art documents] [Patent documents]

[0095] [Patent Document 1] JP2006-353078A

Claims

1. A disk-shaped rotor (50, 60); a stator (70) facing the rotor via an air gap (G1, G2) in an axial direction (X) of the rotor; Equipped with The stator includes a plurality of stator cores (71) arranged in an annular shape when viewed from the axial direction, and a coil (72) wound around each of the stator cores, The rotor has a plurality of through holes (54, 64) penetrating in the axial direction, the plurality of through holes are provided radially inward of the rotor relative to the coil when viewed in the axial direction, a first ratio, which is a ratio between a total area of ​​the plurality of through holes and an opening area of ​​an outer edge portion of the air gap, is 20% or more and 40% or less; An axial gap type motor (40).

2. The plurality of through holes are provided in a circular first region (R1) centered on the rotation axis of the rotor when viewed in the axial direction, The radius of the first region is 40% or less of the radius of the rotor.

2. The axial gap motor according to claim 1.

3. the plurality of through holes are arranged along a circumference of a first circle centered on a rotation axis of the rotor such that centers of the through holes are located on the circumference of the first circle when viewed in the axial direction.

3. The axial gap motor according to claim 1 or 2.

4. The rotors are arranged in a pair, and the stator is sandwiched between the rotors.

3. The axial gap motor according to claim 1 or 2.

5. An axial gap type motor (40) according to claim 1 or 2; A fan (20, 30) driven by the axial gap type motor; The blower device (100) comprises:

6. An air conditioner comprising the blower device (100) according to claim 5.

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