Motors, fans, ventilators, and air conditioners

Abstract

A rotor (2) has: an outer rotor part (22A); and an inner rotor part (22B) provided inside the outer rotor part (22A). The outer rotor part (22A) is a bond magnet having a dielectric constant of more than 40 but not more than 200. The inner rotor part (22B) is an insulator having a dielectric constant of not more than 10. When the outer diameter of the outer rotor part (22A) is denoted as D1, the inner diameter of the outer rotor part (22A) is denoted as D2, the outer diameter of the inner rotor part (22B) is denoted as D3, and the inner diameter of the inner rotor part (22B) is denoted as D4, the rotor (2) satisfies D2=D3 and 0.15≤(D3-D4) / (D1-D2).

Description

[Technical field]

[0001] The present disclosure relates to a rotor, a motor, a fan, a ventilator, and an air conditioner. [Background technology]

[0002] A technology has been proposed to prevent electrolytic corrosion in the bearings by adjusting the rotor's capacitance from 3 pF to 12 pF by adjusting the dielectric constant of resin magnets, such as bonded magnets, that make up the rotating body of a motor to between 10 and 40 (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 042282 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, when a rotor is made of a bonded magnet with a dielectric constant greater than 40, the voltage generated between the inner and outer rings of the bearing (hereinafter also referred to as "bearing voltage") increases, and the discharge current flowing through the bearing increases. As a result, electrolytic corrosion occurs in the bearing, causing problems such as increased vibration and noise in the motor.

[0005] The object of the present disclosure is to solve the above problems, and to reduce the bearing voltage and suppress the discharge current flowing within the bearing, thereby suppressing an increase in motor vibration and noise, even when a bonded magnet with a relative dielectric constant greater than 40 is used in the rotor. [Means for solving the problem]

[0006] The rotor of the present disclosure comprises: An outer rotor portion; an inner rotor portion provided inside the outer rotor portion; Equipped with the outer rotor portion is a bonded magnet having a dielectric constant greater than 40 and less than or equal to 200; the inner rotor portion is an insulator having a dielectric constant of 10 or less; When the outer diameter of the outer rotor portion is D1, the inner diameter of the outer rotor portion is D2, the outer diameter of the inner rotor portion is D3, and the inner diameter of the inner rotor portion is D4, D2=D3, and 0.15≦(D3-D4) / (D1-D2) Meet the following. The motor of the present disclosure comprises: A stator; The rotor is disposed inside the stator; Equipped with. A motor according to another aspect of the present disclosure includes: A stator; a rotor having an outer rotor portion and an inner rotor portion provided inside the outer rotor portion and disposed inside the stator; a conductive shaft fixed inside the inner rotor portion; a bearing that rotatably supports the conductive shaft; A conductive housing; a non-conductive member covering an end of the conductive shaft on the opposite load side; Equipped with the rotor and the stator are disposed within the conductive housing; an outer circumferential surface of the stator is in contact with the conductive housing; The bearing has an inner ring and an outer ring, the outer ring is in contact with the conductive housing; the outer rotor portion is a bonded magnet having a dielectric constant greater than 40 and less than or equal to 200; the inner rotor portion is an insulator having a dielectric constant of 10 or less; When the outer diameter of the outer rotor portion is D1, the inner diameter of the outer rotor portion is D2, the outer diameter of the inner rotor portion is D3, and the inner diameter of the inner rotor portion is D4, D2=D3, and 0.15≦(D3-D4) / (D1-D2) Meet the following. A fan according to another aspect of the present disclosure includes: Feathers and The motor that rotates the blade; Equipped with. A ventilator according to another aspect of the present disclosure includes: Feathers and The motor that rotates the blade; Equipped with. An air conditioner according to another aspect of the present disclosure includes: An indoor unit; an outdoor unit connected to the indoor unit; Equipped with Each of the indoor unit, the outdoor unit, or the indoor unit and the outdoor unit includes the motor. Effect of the Invention

[0007] According to the present disclosure, even when a bonded magnet with a dielectric constant greater than 40 is used in the rotor, the bearing voltage can be reduced, the discharge current flowing through the bearing can be suppressed, and an increase in motor vibration and noise can be suppressed. [Brief description of the drawings]

[0008] [Figure 1] 1 is a cross-sectional view showing a schematic configuration of a motor according to a first embodiment. [Diagram 2] FIG. 2 is a perspective view showing a stator in a simplified form; [Diagram 3] FIG. 2 is a circuit diagram showing an example of an electric circuit. [Figure 4] FIG. 2 is a cross-sectional view illustrating a schematic structure of a rotating body. [Diagram 5] 4 is a graph showing a reduction rate of bearing voltage in the motor according to the first embodiment compared to a comparative motor. [Figure 6] FIG. 11 is a diagram illustrating a schematic configuration of a fan according to a second embodiment. [Figure 7] FIG. 11 is a diagram illustrating a schematic view of a ventilation fan according to a third embodiment. [Figure 8] FIG. 11 is a diagram illustrating a schematic configuration of an air conditioner according to a fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Embodiment 1 The motor 1 according to the first embodiment will be described below. In the xyz Cartesian coordinate system shown in each figure, the z-axis direction (z-axis) indicates a direction parallel to the axis A1 of the motor 1, the x-axis direction (x-axis) indicates a direction perpendicular to the z-axis direction, and the y-axis direction (y-axis) indicates a direction perpendicular to both the z-axis direction and the x-axis direction. The axis A1 is the center of rotation of the rotor 2, i.e., the rotation axis of the rotor 2. The direction parallel to the axis A1 is also referred to as the "axial direction of the rotor 2" or simply as the "axial direction". The radial direction is the radial direction of the rotor 2, the stator 3, or the stator core 31, and is a direction perpendicular to the axis A1. The xy plane is a plane perpendicular to the axial direction. The circumferential direction of the rotor 2, the stator 3, or the stator core 31 is also simply referred to as the "circumferential direction".

[0010] FIG. 1 is a cross-sectional view that diagrammatically illustrates a motor 1 according to a first embodiment. The motor 1 includes a rotor 2, a stator 3, a non-conductive member 4, and a conductive housing 5. The motor 1 is, for example, a permanent magnet synchronous motor.

[0011] 1, the motor 1 may further include an electrical circuit 6 and a connector 7. The rotor 2 and the stator 3 are disposed within a conductive housing 5.

[0012] 1, the stator 3 has a stator core 31, at least one insulator 32, at least one coil 33, and at least one conductive pin 34. Each coil 33 is wound around the insulator 32. The stator 3 is press-fitted into a frame 5A of a conductive housing 5. That is, an outer circumferential surface of the stator 3 (for example, an outer circumferential surface of the stator core 31) is in contact with the conductive housing 5.

[0013] <Stator 3> FIG. 2 is a perspective view that diagrammatically illustrates the stator 3. As shown in FIG. In FIG. 2, the coils 33 are removed from the stator 3 in order to show the structures of the stator core 31 and the insulator 32. The stator core 31 has a yoke 31A extending in the circumferential direction and a plurality of teeth 31B. In this embodiment, the stator core 31 has twelve teeth 31B. Each tooth 31B extends in the radial direction from the yoke 31A. The stator core 31 is a cylindrical core. For example, the stator core 31 is formed of a plurality of electromagnetic steel plates stacked in the axial direction. In this case, each of the plurality of electromagnetic steel plates is formed into a predetermined shape by a punching process. These electromagnetic steel plates are fixed to each other by crimping, welding, adhesive, or the like.

[0014] The coil 33 is a three-phase coil having a U phase, a V phase, and a W phase.

[0015] Each insulator 32 is provided on a tooth 31B. Each insulator 32 is made of, for example, a thermoplastic resin such as polybutylene terephthalate (PBT). Each insulator 32 electrically insulates the stator core 31 (specifically, each tooth 31B of the stator core 31). For example, the insulator 32 is molded integrally with the stator core 31. However, the insulator 32 may be molded in advance and then combined with the stator core 31.

[0016] Each of the conductive pins 34 is fixed to, for example, the insulator 32. Each of the conductive pins 34 electrically connects the coil 33 to the electric circuit 6. Specifically, each of the conductive pins 34 electrically connects the coil 33 to a switching circuit 64b of the inverter circuit 64 of the electric circuit 6.

[0017] <Electric Circuit 6> FIG. 3 is a circuit diagram showing an example of the electric circuit 6. As shown in FIG. 3, the electric circuit 6 has a fuse 61, a filter circuit 62, a power supply circuit 63, and an inverter circuit 64. The electric circuit 6 is configured to be electrically connected to an AC power supply 60.

[0018] When an AC power supply 60 supplies an AC current (for example, AC 100V to AC 240V) to the electric circuit 6, the AC current is supplied to a power supply circuit 63 through a fuse 61 and a filter circuit 62. The AC current is converted by the power supply circuit 63 into a DC current.

[0019] The filter circuit 62 includes a capacitor 62a, a common mode choke coil 62b, and Y capacitors 62c and 62d, and functions as a noise filter.

[0020] The power supply circuit 63 has a rectifier circuit 63a, a smoothing capacitor 63b, and a switching power supply 63c. In the power supply circuit 63, the AC input through the filter circuit 62 is full-wave rectified by the rectifier circuit 63a having a diode bridge, and is thereby converted into a DC. The DC is stored in the smoothing capacitor 63b. The smoothing capacitor 63b generates a DC (e.g., DC 140V or DC 280V) required by the switching circuit 64b. The switching power supply 63c generates a control power (e.g., DC 15V) required by the drive circuit 64a, using the DC generated in the smoothing capacitor 63b.

[0021] The inverter circuit 64 includes a drive circuit 64a and a switching circuit 64b. The switching circuit 64b constitutes a three-phase bridge of U-phase, V-phase, and W-phase formed between the positive bus bar and the negative bus bar. The positive bus bar is connected to the positive terminal of the smoothing capacitor 63b, and the negative bus bar is connected to the negative terminal of the smoothing capacitor 63b. The three transistors on the positive bus bar side are upper arm transistors. The three transistors on the negative bus bar side are lower arm transistors. Each switching element is connected in reverse parallel to a free wheel diode. The connection terminals of the upper arm transistors and the lower arm transistors constitute output terminals and are connected to the U-phase, V-phase, or W-phase of the coil 33.

[0022] The drive circuit 64a generates PWM signals for driving six switching elements in the switching circuit 64b to turn on and off.

[0023] In this embodiment, the motor 1 is driven by magnetic pole position sensorless drive without using a magnetic pole position sensor such as a Hall IC. In this case, the motor 1 has a magnetic pole position estimation means for estimating the magnetic pole position of the rotor 2. The magnetic pole position estimation means estimates the position of the rotor 2 from the current flowing through the coil 33 and the motor constants, and generates a PWM signal for controlling the current supplied to each phase of the coil 33. As a result, the rotor 2 rotates.

[0024] <Rotor 2> The rotor 2 is rotatably disposed inside the stator 3. An air gap exists between the rotor 2 and the stator 3. The rotor 2 has a conductive shaft 21, a rotating body 22, and first and second bearings 23, 24 that rotatably support the conductive shaft 21. The rotor 2 is rotatable about a rotation axis (i.e., an axis line A1).

[0025] The rotating body 22 is fixed to the conductive shaft 21. The rotating body 22 is located between a first bearing 23 and a second bearing 24. The conductive shaft 21 is rotatably supported by the first bearing 23 and the second bearing 24. The conductive shaft 21 is made of a metal such as iron.

[0026] The first bearing 23 is located on the load side of the motor 1 with respect to the rotating body 22. The first bearing 23 rotatably supports the load side of the conductive shaft 21. The second bearing 24 is located on the anti-load side of the motor 1 with respect to the rotating body 22. The second bearing 24 rotatably supports the anti-load side of the conductive shaft 21.

[0027] In the example shown in FIG. 1, the load side of the conductive shaft 21 protrudes outside the conductive housing 5, and the anti-load side of the conductive shaft 21 does not protrude outside the conductive housing 5.

[0028] In this embodiment, the anti-load side of the conductive shaft 21 does not protrude outside the conductive housing 5, but the anti-load side of the conductive shaft 21 may protrude outside the conductive housing 5.

[0029] 1, the outer diameter of the end of the conductive shaft 21 on the anti-load side is smaller than the outer diameter of the other portion of the conductive shaft 21. The non-conductive member 4 covers the end of the conductive shaft 21 on the anti-load side. For example, the load side of the conductive shaft 21 is provided with a vane for generating an air flow.

[0030] Since the non-conductive member 4 covers the end of the conductive shaft 21 on the anti-load side, the bearing voltage in the second bearing 24 can be reduced.

[0031] A non-conductive member may be provided on the load side of the conductive shaft 21. In this case, the bearing voltage in the first bearing 23 can be reduced.

[0032] FIG. 4 is a cross-sectional view that illustrates a schematic structure of the rotor 22. As shown in FIG. The rotor 22 has an outer rotor portion 22A and an inner rotor portion 22B provided inside the outer rotor portion 22A. The outer rotor portion 22A is ring-shaped. The outer rotor portion 22A is disposed outside the inner rotor portion 22B and is integrated with the inner rotor portion 22B. The conductive shaft 21 is fixed inside the inner rotor portion 22B.

[0033] D1 is the outer diameter of the outer rotor portion 22A, D2 is the inner diameter of the outer rotor portion 22A, D3 is the outer diameter of the inner rotor portion 22B, and D4 is the inner diameter of the inner rotor portion 22B. In the example shown in FIG. 4, D2=D3.

[0034] The outer rotor portion 22A forms the magnetic poles of the rotor 2 (specifically, the rotating body 22). When the outer rotor portion 22A is molded, a magnetic field is applied to the outer rotor portion 22A, so that the outer rotor portion 22A is oriented along the applied magnetic field. The magnetic field is oriented in a polar anisotropic manner. In this embodiment, the outer rotor portion 22A has N poles and S poles formed alternately in the circumferential direction. The rotating body 22 (specifically, the outer rotor portion 22A) forms eight poles. The number of magnetic poles is not limited to eight. For example, the number of magnetic poles may be two or more, and is not necessarily eight.

[0035] The outer rotor portion 22A is disposed on the outermost periphery of the rotor 22. The outer rotor portion 22A is a bonded magnet. The inner rotor portion 22B is an insulator containing resin, elastomer, air, or the like.

[0036] The insulator constituting the inner rotor part 22B is, for example, a resin such as polyamide resin or polybutylene terephthalate. In the present embodiment, the inner rotor part 22B is a resin having a relative dielectric constant of 10 or less. When the resin constituting the inner rotor part 22B is polyamide resin or polybutylene terephthalate, the inner rotor part 22B can be manufactured by injection molding, and the degree of freedom in the shape of the rotor 2 can be improved.

[0037] The bonded magnet constituting the outer rotor portion 22A is made of a composite material containing, for example, resin and magnetic powder. For example, this bonded magnet is obtained by injection molding the resin and magnetic powder. The magnetic powder used in the bonded magnet is, for example, strontium ferrite (SrO 6Fe 2 O 3 ), barium ferrite (BaO / 6F 2 O 3 When the magnetic powder is ferrite, the cost of the rotor 2 can be reduced. The resin used for the bonded magnet is a thermoplastic resin such as polyamide resin (6PA, 12PA, PA6T) or polyphenylene sulfide (PPS).

[0038] When the resin used in the bonded magnet is a polyamide resin, a rotor 2 (specifically, a rotor 22) with high mechanical strength and good heat resistance is obtained. Furthermore, 12PA produces a bonded magnet with less water absorption and less variation in dielectric constant than 6PA. By using polyphenylene sulfide (PPS) as the resin contained in the bonded magnet, a rotor with less water absorption, less variation in dielectric constant, and good dimensional stability is obtained.

[0039] The relative dielectric constant of resin is about 3 to 10. In contrast, the relative dielectric constant of ferrite is about 250, which is much larger than that of resin. Until now, no attention has been paid to the characteristic distribution of the relative dielectric constant of ferrite bonded magnets, which are made up of resin with a low relative dielectric constant and ferrite magnetic powder with a high relative dielectric constant, and it has not been listed in magnet characteristic tables.

[0040] We actually measured the dielectric constant εr of bonded magnets containing ferrite. To measure the dielectric constant, we created a dice-shaped square piece, attached aluminum foil to the opposing surfaces of the square piece, measured the capacitance between both ends with an LCR meter, and calculated the dielectric constant from the results using the following formula. The capacitance was measured under the following conditions: frequency 16kHz, voltage 1.5V, and temperature 20℃. εr=C×d / (S×ε 0 ) C: capacitance [F], d: distance between opposing measurement surfaces [m], S: area of ​​measurement surface [m 2 ], ε 0 : Dielectric constant of vacuum (8.854×10 -12 [F / m])

[0041] As a result of the above measurements, it was discovered that the dielectric constants of 32 sample bonded magnets containing ferrite, which were made under different conditions such as the time since molding and the material lots, were distributed widely, with the lower limit being greater than 40 and the upper limit being less than 200. In other words, the dielectric constant of the bonded magnet has a large effect on the bearing voltage. For this reason, it is desirable for the outer rotor portion 22A to be a bonded magnet with a dielectric constant greater than 40 and less than 200.

[0042] FIG. 5 is a graph showing the reduction rate of the bearing voltage in motor 1 according to embodiment 1 compared to a comparative motor. The horizontal axis is (D3-D4) / (D1-D2). The vertical axis indicates the reduction rate of the bearing voltage in motor 1 according to this embodiment, when the bearing voltage in the comparative motor is used as a reference. In other words, the vertical axis indicates that the greater the reduction rate, the smaller the bearing voltage, and that a reduction rate of 100% results in a bearing voltage of 0 V. In the comparative rotor, the rotating body is ring-shaped with an outer diameter of Φ42 mm and an inner diameter of Φ8 mm, and the rotating body is made of a bonded magnet with a relative dielectric constant of 200. That is to say, in the comparative motor, the rotating body is made of only a bonded magnet.

[0043] As shown in Figure 5, the reduction rate of the bearing voltage for the comparative rotor changes almost linearly up to about 80%, and the rate of change gradually decreases in the region where the reduction rate is 80% or more. When the reduction rate is 80%, (D3-D4) / (D1-D2) is 0.15. Therefore, when (D3-D4) / (D1-D2) is 0.15 or more, the bearing voltage can be effectively reduced and the life of the bearing can be extended.

[0044] Therefore, in this embodiment, when the outer diameter of outer rotor portion 22A is D1, the inner diameter of outer rotor portion 22A is D2, the outer diameter of inner rotor portion 22B is D3, and the inner diameter of inner rotor portion 22B is D4, motor 1 satisfies D2=D3 and 0.15≦(D3-D4) / (D1-D2). With this configuration, it is possible to reduce the bearing voltage, suppress the discharge current flowing through the bearing, and suppress an increase in vibration and noise of motor 1 due to electrolytic corrosion of first bearing 23 or second bearing 24.

[0045] <First bearing 23> The first bearing 23 has a first conductive inner ring 23A, a first conductive outer ring 23B, and two or more balls 23C. The two or more balls 23C are disposed between the first conductive inner ring 23A and the first conductive outer ring 23B. Each ball 23C is conductive. Each ball 23C is filled with a lubricant. The lubricant filled in each ball 23C is non-conductive. The first conductive inner ring 23A, the first conductive outer ring 23B, and each ball 23C are made of a metal such as iron.

[0046] The first conductive inner ring 23A is fixed to the conductive shaft 21. That is, the first conductive inner ring 23A is in contact with the conductive shaft 21. The first conductive inner ring 23A is fixed to the conductive shaft 21, for example, by press-fitting or adhesive. When the first conductive inner ring 23A rotates together with the conductive shaft 21, a thin oil film layer is formed between the outer peripheral surface, which is the raceway surface of the first conductive inner ring 23A, and each of the balls 23C, and a thin oil film layer is formed between the inner peripheral surface, which is the raceway surface of the first conductive outer ring 23B, and each of the balls 23C. As a result, the first conductive inner ring 23A and the first conductive outer ring 23B are electrically insulated from each of the balls 23C.

[0047] The outer diameter of the first bearing 23 (specifically, the first conductive outer ring 23B) and the inner diameter of the first housing 51 of the frame 5A are approximately equal. The first bearing 23 (specifically, the first conductive outer ring 23B) is fixed to the first housing 51 by, for example, press fitting or adhesive. In this embodiment, the first conductive outer ring 23B is in contact with the conductive casing 5. The first bearing 23 (specifically, the first conductive outer ring 23B) may be disposed in the first housing 51 with a clearance fit.

[0048] <Second bearing 24> The second bearing 24 has a second conductive inner ring 24A, a second conductive outer ring 24B, and two or more balls 24C. The two or more balls 24C are disposed between the second conductive inner ring 24A and the second conductive outer ring 24B. Each ball 24C is conductive. A lubricant is applied to each ball 24C. The lubricant applied to each ball 24C is non-conductive. The second conductive inner ring 24A, the second conductive outer ring 24B, and each ball 24C are made of a metal such as iron.

[0049] The second conductive inner ring 24A is fixed to the non-conductive member 4 by, for example, press-fitting or adhesive. When the second conductive inner ring 24A rotates together with the conductive shaft 21 and the non-conductive member 4, a thin oil film layer is formed between the outer peripheral surface, which is the raceway surface of the second conductive inner ring 24A, and each of the balls 24C, and a thin oil film layer is formed between the inner peripheral surface, which is the raceway surface of the second conductive outer ring 24B, and each of the balls 24C. As a result, the second conductive inner ring 24A and the second conductive outer ring 24B are electrically insulated from each of the balls 24C.

[0050] The outer diameter of the second bearing 24 (specifically, the second conductive outer ring 24B) and the inner diameter of the second housing 52 of the bracket 5B are approximately equal. The second bearing 24 (specifically, the second conductive outer ring 24B) is fixed to the conductive housing 5 (specifically, the second housing 52 of the bracket 5B) by, for example, press fitting or adhesive. In this embodiment, the second conductive outer ring 24B is in contact with the conductive housing 5. The second bearing 24 (specifically, the second conductive outer ring 24B) may be disposed in the conductive housing 5 (specifically, the second housing 52 of the bracket 5B) by clearance fit.

[0051] The thickness of the oil film layer is, for example, 1 μm or less, but the thickness of the oil film layer varies depending on several factors such as the rotation speed of the rotor 2 or the temperature inside the motor 1 .

[0052] A preload spring is provided between the second bearing 24 and the bracket 5B (specifically, the second housing 52) to apply an axial preload to the second bearing 24. Since the axial preload is applied to the first bearing 23 and the second bearing 24 by the preload spring, rattling of the balls 23C and the balls 24C during rotation of the rotor 2 can be prevented.

[0053] In this embodiment, the size of the first bearing 23 is equal to the size of the second bearing 24. Therefore, the outer diameter (i.e., diameter) of the first conductive outer ring 23B is equal to the outer diameter (i.e., diameter) of the second conductive outer ring 24B. Each of the first bearing 23 and the second bearing 24 is, for example, a deep groove ball bearing of designation 608 with an outer diameter of φ22 mm, an inner diameter of 8 mm, and a width of 7 mm. In this embodiment, the size of the first bearing 23 is equal to the size of the second bearing 24, but the size of the first bearing 23 may be different from that of the second bearing 24.

[0054] <Conductive housing 5> 1, the conductive housing 5 has a frame 5A in which the stator 3 and the rotor 2 are arranged, and a bracket 5B that covers the inside of the frame 5A. That is, the stator 3 and the rotor 2 are arranged in the conductive housing 5 (specifically, the frame 5A). The conductive housing 5 is made of a metal such as iron.

[0055] The frame 5A is a conductive frame. The frame 5A is made of a metal such as iron. The inner surface of the frame 5A is mechanically and electrically connected to the outer circumferential surface of the stator core 31. The stator 3 is grounded via the frame 5A. The frame 5A is, for example, a cup-shaped frame. The frame 5A has a first housing 51 in which the first bearing 23 is arranged. The first housing 51 is a part of the frame 5A and is provided on the bottom of the frame 5A. In the example shown in FIG. 1, the first housing 51 is a part of the bottom of the frame 5A that protrudes in the axial direction and in a direction perpendicular to the axial direction in the xy plane. In the example shown in FIG. 1, the first conductive outer ring 23B of the first bearing 23 is in contact with the first housing 51.

[0056] The first housing 51 has a through hole 51A, and the conductive shaft 21 protrudes to the outside of the frame 5A through the through hole 51A.

[0057] The bracket 5B is a conductive bracket. The bracket 5B is made of a metal such as iron. The frame 5A and the bracket 5B are electrically connected. The bracket 5B has a second housing 52 in which the second bearing 24 is arranged. A portion of the bracket 5B other than the second housing 52 is, for example, a flat plate. The second housing 52 is a part of the bracket 5B, and is a portion of the bracket 5B that protrudes in the axial direction from the flat plate. In the example shown in FIG. 1, the second conductive outer ring 24B of the second bearing 24 is in contact with the second housing 52.

[0058] Since the frame 5A and the bracket 5B are mechanically and electrically connected, the first conductive outer ring 23B of the first bearing 23 and the second conductive outer ring 24B of the second bearing 24 can be made to have the same potential with a simple configuration, and the bearing voltage can be reduced.

[0059] As shown in FIG. 1, the conductive housing 5 may further include a circuit cover 5C. The circuit cover 5C is a conductive cover. The circuit cover 5C is made of a metal such as iron. The circuit cover 5C may be made of resin. As shown in FIG. 1, the circuit cover 5C covers the electric circuit 6. Specifically, the circuit cover 5C covers the electric circuit 6 together with the bracket 5B. In this embodiment, the electric circuit 6 is disposed inside the conductive housing 5, but a part or the whole of the electric circuit 6 may be disposed outside the conductive housing 5.

[0060] As shown in FIG. 1, a circuit case 5D for fixing the electric circuit 6 may be disposed within the circuit cover 5C. In this case, the circuit case 5D is disposed within the circuit cover 5C. The circuit case 5D is fixed to, for example, a bracket 5B. The circuit case 5D is a non-conductive case. The circuit case 5D is made of, for example, a non-conductive resin. For example, a recess in which the electric circuit 6 is disposed is formed in the circuit case 5D by press molding.

[0061] Each of the frame 5A, the bracket 5B, and the circuit cover 5C has a flange 53 that forms an outer periphery. The flanges 53 of the frame 5A, the bracket 5B, and the circuit cover 5C are fixed to each other, for example, by screws. Therefore, the frame 5A, the bracket 5B, and the circuit cover 5C are mechanically linked and electrically connected to each other. That is, in the example shown in FIG. 1, the conductive housing 5 is divided by the bracket 5B into a motor housing section 54 in which the rotor 2 and the stator 3 are arranged, and a circuit housing section 55 in which the electric circuit 6 is arranged.

[0062] The frame 5A, the bracket 5B, and the circuit cover 5C may be electrically connected to each other. In the present embodiment, the frame 5A and the bracket 5B are made of a conductive material, but one of the frame 5A and the bracket 5B may be made of a non-conductive material such as a non-conductive resin, or both of the frame 5A and the bracket 5B may be made of a non-conductive material such as a non-conductive resin.

[0063] When the frame 5A is made of a conductive material, a non-conductive member such as a non-conductive resin may be disposed between the first conductive inner ring 23A and the conductive shaft 21. With this configuration, the bearing voltage in the first bearing 23 can be reduced.

[0064] The non-conductive resin is, for example, a bulk molding compound resin (BMC resin) such as unsaturated polyester. In this case, the dimensional accuracy of the parts can be improved, and the mechanical strength of the motor 1 can be increased.

[0065] <Connector 7> 1, the connector 7 is fixed to the circuit cover 5C. The connector 7 has, for example, wiring and a non-conductive cover that covers the wiring. The wiring of the connector 7 is connected to the electric circuit 6.

[0066] Embodiment 2 FIG. 6 is a diagram illustrating a schematic configuration of a fan 9 according to the second embodiment. The fan 9 has a blade 91 and a motor 1. The fan 9 is also called a blower. The blade 91 is made of, for example, polypropylene (PP) containing glass fiber. The blade 91 is, for example, a sirocco fan, a propeller fan, a crossflow fan, or a turbo fan.

[0067] The motor 1 is the motor 1 according to the first embodiment. The blades 91 are fixed to a shaft of the motor 1. The motor 1 drives the blades 91. Specifically, the motor 1 rotates the blades 91. When the motor 1 is driven, the blades 91 rotate and an airflow is generated. This enables the fan 9 to blow air.

[0068] The fan 9 according to the second embodiment has the motor 1 according to the first embodiment, and therefore can obtain the same advantages as those described in the first embodiment. Furthermore, the performance of the fan 9 can be maintained for a long period of time.

[0069] Furthermore, since fan 9 according to embodiment 2 has motor 1 according to embodiment 1, vibration and noise in fan 9 can be reduced.

[0070] Embodiment 3 FIG. 7 is a diagram illustrating a schematic configuration of a ventilation fan 8 according to the third embodiment. The ventilation fan 8 has blades 81 and a motor 1 that rotates the blades 81. The motor 1 is the motor 1 described in the first embodiment. The blades 81 are fixed to the load side of the conductive shaft 21 of the motor 1.

[0071] The exhaust fan 8 can be used for a wide range of purposes, including residential and commercial use. For example, it is used in residential living rooms, kitchens, bathrooms, and toilets. The blades 81 and at least a part of the motor 1 are covered by a exhaust fan body 82. The conductive housing 5 of the motor 1 is fixed to the exhaust fan body 82 with screws 83. The exhaust fan body 82 is provided with a power connection terminal block 84 and an earth connection terminal 85.

[0072] The connector 7 of the motor 1 is connected to a power supply connection terminal block 84. One end of the external connection terminals of the power supply connection terminal block 84 is connected to one end of the power supply line of the AC power supply through a switch 86, and the other end of the external connection terminals of the power supply connection terminal block 84 is directly connected to the other end of the power supply line of the AC power supply. That is, the supply of power to the motor 1 is controlled by turning on and off the switch 86. When the switch 86 is turned on, power is supplied to the motor 1, and the blades 81 fixed to the conductive shaft 21 of the motor 1 rotate, thereby ventilating the room.

[0073] Since the ventilation fan 8 has the motor 1 according to the first embodiment, it is possible to obtain the same advantages as those described in the first embodiment. As a result, the performance of the ventilation fan 8 can be maintained for a long period of time.

[0074] Furthermore, since the ventilation fan 8 has the motor 1 according to the first embodiment, the vibration and noise in the ventilation fan 8 can be reduced.

[0075] The flange 53 of the conductive housing 5 is fixed to the exhaust fan body 82 of the exhaust fan 8 with a screw 83. The frame 5A of the motor 1 is disposed inside the exhaust fan body 82. The electric circuit 6 of the motor 1 is disposed outside the exhaust fan body 82. A bracket 5B is disposed between the electric circuit 6 and the rotor 2. Therefore, the electric circuit 6 is isolated from the rotor 2, and is therefore less susceptible to the temperature and humidity inside the exhaust fan body 82. Therefore, the stable performance of the exhaust fan 8 can be maintained for a long period of time. As a result, an increase in noise in the exhaust fan 8 due to electrolytic corrosion of the first bearing 23 or the second bearing 24 can be prevented, and a comfortable space can be provided for a long period of time.

[0076] When the conductive housing 5 of the motor 1 is a metal housing, the strength of the motor 1 for holding the rotor 2 is improved. Therefore, when the conductive housing 5 of the motor 1 is a metal housing, heavy blades such as large blades and metallic blades can be applied to the blades 81.

[0077] Embodiment 4 An air conditioner 10 (also referred to as a refrigeration and air conditioning device or a refrigeration cycle device) according to a fourth embodiment will be described. FIG. 8 is a diagram showing a schematic configuration of an air conditioner 10 according to the fourth embodiment.

[0078] The air conditioner 10 according to embodiment 4 has an indoor unit 11 serving as a blower (also referred to as a first blower) and an outdoor unit 13 serving as a blower (also referred to as a second blower) connected to the indoor unit 11.

[0079] In this embodiment, the air conditioner 10 has an indoor unit 11, a refrigerant pipe 12, and an outdoor unit 13. For example, the outdoor unit 13 is connected to the indoor unit 11 through the refrigerant pipe 12.

[0080] The indoor unit 11 has a motor 11a (for example, the motor 1 according to the first embodiment), an air blower 11b that is driven by the motor 11a to blow air, and a housing 11c that covers the motor 11a and the air blower 11b. The air blower 11b has, for example, a blade 11d that is driven by the motor 11a. For example, the blade 11d is fixed to a shaft of the motor 11a and generates an airflow.

[0081] The outdoor unit 13 has a motor 13a (for example, the motor 1 according to the first embodiment), a blower 13b, a compressor 14, a heat exchanger (not shown), and a housing 13c that covers the blower 13b, the compressor 14, and the heat exchanger. The blower 13b blows air by being driven by the motor 13a. The blower 13b has, for example, blades 13d that are driven by the motor 13a. For example, the blades 13d are fixed to the shaft of the motor 13a and generate an airflow. The compressor 14 has a motor 14a (for example, the motor 1 according to the first embodiment), a compression mechanism 14b (for example, a refrigerant circuit) that is driven by the motor 14a, and a housing 14c that covers the motor 14a and the compression mechanism 14b.

[0082] In the air conditioner 10, at least one of the indoor unit 11 and the outdoor unit 13 has the motor 1 described in the first embodiment. That is, the indoor unit 11, the outdoor unit 13, or the indoor unit 11 and the outdoor unit 13 each have the motor 1 described in the first embodiment. Specifically, as a drive source for the blower, the motor 1 described in the first embodiment is applied to at least one of the motors 11a and 13a. That is, the motor 1 described in the first embodiment is applied to the indoor unit 11, the outdoor unit 13, or the indoor unit 11 and the outdoor unit 13. The motor 1 described in the first embodiment may be applied to the motor 14a of the compressor 14.

[0083] The air conditioner 10 can perform air conditioning such as cooling operation to blow cold air from the indoor unit 11 and heating operation to blow warm air. In the indoor unit 11, the motor 11a is a drive source for driving the blower unit 11b. The blower unit 11b can blow conditioned air.

[0084] In the indoor unit 11, the motor 11a is fixed to a housing 11c of the indoor unit 11 by, for example, screws. In the outdoor unit 13, the motor 13a is fixed to a housing 13c of the outdoor unit 13 by, for example, screws.

[0085] In the air conditioner 10 according to the fourth embodiment, the motor 1 described in the first embodiment is applied to at least one of the motors 11a and 13a, and therefore it is possible to obtain the same advantages as those described in the first embodiment. As a result, the performance of the air conditioner 10 can be maintained for a long period of time.

[0086] Furthermore, when the motor 1 according to the first embodiment is used as a drive source for a blower (e.g., indoor unit 11), the same advantages as those described in the first embodiment can be obtained. As a result, the performance of the blower is maintained for a long period of time. A blower having the motor 1 according to the first embodiment and a blade (e.g., blade 11d or 13d) driven by the motor 1 can be used alone as a device for blowing air. This blower can also be applied to devices other than the air conditioner 10.

[0087] Furthermore, when the motor 1 according to the first embodiment is used as the drive source of the compressor 14, the same advantages as those described in the first embodiment can be obtained. As a result, the performance of the compressor 14 can be maintained for a long period of time.

[0088] The motor 1 described in the first embodiment can be mounted on home appliances such as a vacuum cleaner, in addition to the air conditioner 10. Furthermore, the motor 1 described in the first embodiment can be mounted on any electric device having a drive source, such as a machine tool, an electric vehicle, a drone, or a robot.

[0089] The features of each of the embodiments described above can be combined with each other. [Explanation of symbols]

[0090] 1,11a,13a,14a motor, 2 rotor, 3 stator, 4 non-conductive member, 5 conductive housing, 5A frame, 5B bracket, 6 electrical circuit, 7 connector, 8 ventilation fan, 9 fan, 10 air conditioner, 11 indoor unit, 12 refrigerant piping, 13 outdoor unit, 21 conductive shaft, 22 rotating body, 23 first bearing, 23A first conductive inner ring, 23B first conductive outer ring, 23C,24C ball, 24 second bearing, 24A second conductive inner ring, 24B second conductive outer ring, 31 stator core, 32 insulator, 33 coil, 51 first housing, 52 second housing, 81,91 blades.

Claims

1. A stator, a rotor having an outer rotor portion and an inner rotor portion provided inside the outer rotor portion and disposed inside the stator; a conductive shaft fixed inside the inner rotor portion; a bearing that rotatably supports the conductive shaft; A conductive housing; a non-conductive member covering an end of the conductive shaft on the opposite load side; Equipped with the rotor and the stator are disposed within the conductive housing; an outer circumferential surface of the stator is in contact with the conductive housing; The bearing has an inner ring and an outer ring, the outer ring is in contact with the conductive housing; the outer rotor portion is a bonded magnet having a dielectric constant greater than 40 and less than or equal to 200; the inner rotor portion is an insulator having a dielectric constant of 10 or less; When the outer diameter of the outer rotor portion is D1, the inner diameter of the outer rotor portion is D2, the outer diameter of the inner rotor portion is D3, and the inner diameter of the inner rotor portion is D4, D2=D3, and 0.15≦(D3−D4) / (D1−D2) Meet the motor.

2. 2. The motor according to claim 1, wherein the insulator is made of a polyamide resin or polybutylene terephthalate.

3. The bonded magnet includes a magnetic powder and a resin, The magnetic powder is ferrite.

3. The motor according to claim 1 or 2.

4. The motor according to claim 3 , wherein the resin contained in the bonded magnet is a polyamide resin.

5. 4. The motor according to claim 3, wherein the resin contained in the bonded magnet is polyphenylene sulfide.

6. Feathers and The motor according to any one of claims 1 to 5, which rotates the blades; A fan equipped with

7. Feathers and The motor according to any one of claims 1 to 5, which rotates the blades; A ventilation fan equipped with

8. An indoor unit; an outdoor unit connected to the indoor unit; Equipped with The indoor unit, the outdoor unit, or both the indoor unit and the outdoor unit each have a motor according to any one of claims 1 to 5. Air conditioner.

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