JP7450817B2 - Motors, fans, ventilation fans, and air conditioners - Google Patents

Description

The present disclosure relates to motors, fans, ventilation fans, and air conditioners.

A motor has been proposed that includes a housing in which a pair of bearings that rotatably support a rotor shaft are disposed (for example, see Patent Document 1).

International Publication No. 2019/167233

Generally, when the housing in which the first bearing of the pair of bearings is arranged is electrically conductive, the first bearing is electrically connected to the housing and the second bearing of the pair of bearings is fixed. If the shaft is electrically conductive, the second bearing is electrically connected to the shaft. In this case, the voltage between the inner ring and outer ring of each bearing increases, and the current flowing through the bearing increases. As a result, there is a problem in that electrolytic corrosion occurs in the bearings, and vibration and noise in the motor increase.

An objective of the present disclosure is to reduce the current flowing through the bearing.

The motor of the present disclosure includes:
stator and
a rotor that is disposed inside the stator and has a conductive shaft and first and second bearings that rotatably support the conductive shaft;
a first non-conductive member;
a second non-conductive member disposed between the second bearing and the conductive shaft;
a conductive housing having a first housing in which the first non-conductive member is disposed, a second housing in which the second bearing is disposed, and in which the stator and rotor are disposed; Prepare,
The first bearing has a first conductive inner ring and a first conductive outer ring,
The second bearing has a second conductive inner ring and a second conductive outer ring,
the first conductive outer ring is insulated from the first housing by the first non-conductive member;
the first conductive inner ring is in contact with the conductive shaft;
the second conductive inner ring is insulated from the conductive shaft by the second non-conductive member;
The second conductive outer ring is in contact with the second housing.
A fan according to another aspect of the present disclosure includes:
feathers and
and the motor that rotates the blade.
A ventilation fan according to another aspect of the present disclosure,
feathers and
and the motor that rotates the blade.
An air conditioner according to another aspect of the present disclosure includes:
indoor unit and
an outdoor unit connected to the indoor unit;
The indoor unit, the outdoor unit, or each of the indoor unit and the outdoor unit includes the motor.

According to the present disclosure, it is possible to reduce the current flowing through the bearing.

1 is a cross-sectional view schematically showing a motor according to Embodiment 1. FIG. FIG. 2 is a perspective view schematically showing a stator. FIG. 2 is a circuit diagram showing an example of an electric circuit. FIG. 2 is a cross-sectional view of the conductive casing shown in FIG. 1. FIG. It is a graph showing the relationship between the maximum thickness [mm] and capacitance [pF] in the radial direction of each of the first non-conductive member and the second non-conductive member. The first capacitance and the second capacitance for the ratio t1/t2 in the case where the first capacitance of the first non-conductive member and the second capacitance of the second non-conductive member are equal. It is a graph showing the relationship between each capacitance. FIG. 3 is a diagram schematically showing a fan according to a second embodiment. FIG. 7 is a diagram schematically showing a ventilation fan according to a third embodiment. FIG. 7 is a diagram schematically showing the configuration of an air conditioner according to Embodiment 4.

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

FIG. 1 is a cross-sectional view schematically showing a motor 1 according to the first embodiment.
The motor 1 includes a rotor 2, a stator 3, a first non-conductive member 4A, a second non-conductive member 4B, and a conductive housing 5. The motor 1 is, for example, a permanent magnet synchronous motor.

As shown in FIG. 1, the motor 1 may further include an electric circuit 6 and a connector 7.

As shown in FIG. 1, the stator 3 includes 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 an insulator 32. The stator 3 is press-fitted into the frame 5A of the conductive housing 5.

<Stator 3>
FIG. 2 is a perspective view schematically showing the stator 3. FIG.
In FIG. 2, the coil 33 is removed from the stator 3 to show the structure of the stator core 31 and insulator 32.
Stator core 31 has a yoke 31A extending in the circumferential direction and a plurality of teeth 31B. In this embodiment, stator core 31 has 12 teeth 31B. Each tooth 31B extends in the radial direction from the yoke 31A. Stator core 31 is a cylindrical core. For example, the stator core 31 is formed of a plurality of electromagnetic steel plates laminated in the axial direction. In this case, each of the plurality of electromagnetic steel sheets is formed into a predetermined shape by a punching process. These electromagnetic steel plates are fixed to each other by caulking, welding, adhesion, or the like.

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

Each insulator 32 is provided on the teeth 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 the molded insulator 32 may be combined with the stator core 31.

Each conductive pin 34 is fixed to the insulator 32, for example. Each conductive pin 34 electrically connects the coil 33 and the electric circuit 6. Specifically, each conduction pin 34 electrically connects the coil 33 and the switching circuit 64b of the inverter circuit 64 of the electric circuit 6.

<Electrical circuit 6>
FIG. 3 is a circuit diagram showing an example of the electric circuit 6. As shown in FIG.
In the example shown in FIG. 3, the electric circuit 6 includes 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 source 60.

When AC (for example, AC 100V to AC 240V) is supplied from AC power supply 60 to electric circuit 6, the AC is supplied to power supply circuit 63 through fuse 61 and filter circuit 62. The alternating current is converted into direct current by the power supply circuit 63.

The filter circuit 62 includes an X capacitor 62a, a common mode choke coil 62b, and Y capacitors 62c and 62d. With this configuration, the filter circuit 62 constitutes a noise filter.

The power supply circuit 63 includes a rectifier circuit 63a, a smoothing capacitor 63b, and a switching power supply 63c. In the power supply circuit 63, the alternating current input through the filter circuit 62 is full-wave rectified by a rectifier circuit 63a having a diode bridge, thereby converting it into direct current. The direct current is accumulated in the smoothing capacitor 63b. In the smoothing capacitor 63b, the direct current (for example, 140 VDC or 280 VDC) required by the switching circuit 64b is generated. The switching power supply 63c uses the DC generated in the smoothing capacitor 63b to generate control power (for example, DC 15V) required by the drive circuit 64a.

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 busbar and the negative busbar. The positive bus bar is connected to the positive end of the smoothing capacitor 63b, and the negative bus bar is connected to the negative end of the smoothing capacitor 63b. The three transistors on the positive bus side are upper arm transistors. The three transistors on the negative bus side are lower arm transistors. Each switching element is connected in antiparallel to a freewheeling diode. A connection end of each of the upper arm transistor and the lower arm transistor constitutes an output end, and is connected to the U phase, V phase, or W phase of the coil 33.

The drive circuit 64a generates a PWM signal for turning on and off six switching elements of the switching circuit 64b.

In this embodiment, the motor 1 is driven by magnetic pole position sensorless driving 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 constant, and generates a PWM signal for controlling the current supplied to each phase of the coil 33. As a result, the rotor 2 rotates.

<Rotor 2>
The rotor 2 is rotatably arranged inside the stator 3. An air gap exists between the rotor 2 and the stator 3. The rotor 2 includes a conductive shaft 21, a permanent magnet 22, and first and second bearings 23 and 24 that rotatably support the conductive shaft 21. The rotor 2 is rotatable around a rotation axis (ie, axis A1).

In this embodiment, permanent magnet 22 is a plastic magnet. Plastic magnets are produced, for example, by mixing raw materials for permanent magnets with resin and molding the mixture. The permanent magnet 22 has N poles and S poles arranged alternately in the circumferential direction.

The entire permanent magnet 22 may be a plastic magnet, or a part of the permanent magnet 22 may be a plastic magnet. When part of the permanent magnet 22 is a plastic magnet, it is preferable that the outer peripheral surface of the permanent magnet 22 is formed of a plastic magnet. In this case, for example, the outer peripheral surface of the permanent magnet 22 may be formed of a plastic magnet, and the inside of the plastic magnet may be filled with resin.

Permanent magnet 22 is fixed to conductive shaft 21 . Permanent magnet 22 is located between first bearing 23 and second bearing 24 . The conductive shaft 21 is rotatably supported by a first bearing 23 and a second bearing 24. The conductive shaft 21 is made of metal such as iron, for example.

The first bearing 23 is located on the load side of the motor 1 with respect to the permanent magnet 22. The first bearing 23 rotatably supports the load side of the conductive shaft 21. The second bearing 24 is located on the opposite load side of the motor 1 with respect to the permanent magnet 22. The second bearing 24 rotatably supports the anti-load side of the conductive shaft 21.

In the example shown in FIG. 1, the load side of the conductive shaft 21 protrudes to the outside of the conductive housing 5, and the anti-load side of the conductive shaft 21 does not protrude to the outside of the conductive housing 5. Since the non-load side of the conductive shaft 21 does not protrude outside the conductive housing 5, the second non-conductive member 4B can be easily integrally provided at the end of the conductive shaft 21 on the non-load side. be able to.

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

In the example shown in FIG. 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 second non-conductive member 4B 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 vanes for generating airflow.

<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. Two or more balls 23C are arranged between the first conductive inner ring 23A and the first conductive outer ring 23B. Each ball 23C is conductive. A lubricant is applied to each ball 23C. The lubricant applied to 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 metal such as iron, for example.

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 by press fitting or adhesive, for example. 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 ball 23C, and the first conductive A thin oil film layer is formed between the inner peripheral surface, which is the raceway surface of the outer ring 23B, and each ball 23C. As a result, the first conductive inner ring 23A and the first conductive outer ring 23B are electrically insulated from each ball 23C.

The first bearing 23 (specifically, the first conductive outer ring 23B) is fixed to the first non-conductive member 4A by press fitting or adhesive, for example. The first bearing 23 (specifically, the first conductive outer ring 23B) may be disposed in the first non-conductive member 4A with a clearance fit.

<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. Two or more balls 24C are arranged between the second conductive inner ring 24A and the second conductive outer ring 24B. Each ball 24C is electrically 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 metal such as iron, for example.

The second conductive inner ring 24A is fixed to the second non-conductive member 4B, for example, by press fit or adhesive. When the second conductive inner ring 24A rotates together with the conductive shaft 21 and the second non-conductive member 4B, 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 ball 24C. is formed, 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 ball 24C. As a result, the second conductive inner ring 24A and the second conductive outer ring 24B are electrically insulated from each ball 24C.

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 casing 5 (specifically, the second housing 52 of the bracket 5B) by press-fitting or adhesive, for example. has been done. 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) with a clearance fit. good.

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

A preload spring is provided between the second bearing 24 and the bracket 5B (specifically, the second housing 52) for applying preload to the second bearing 24 in the axial direction. Since the preload in the axial direction by the preload spring is applied to the first bearing 23 and the second bearing 24, it is possible to prevent the balls 23C and 24C from shaking while the rotor 2 is rotating.

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 608 type deep groove ball bearing with an outer diameter of 22 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 the size of the second bearing 24.

<Conductive housing 5>
FIG. 4 is a sectional view showing the conductive casing 5 shown in FIG.
The conductive housing 5 includes a frame 5A in which the stator 3 and 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 a conductive housing 5 (specifically, a frame 5A in FIG. 4). The conductive housing 5 is made of metal such as iron, for example.

Frame 5A is a conductive frame. The frame 5A is made of metal such as iron, for example. The frame 5A is, for example, a cup-shaped frame. The frame 5A has a first housing 51 in which a first non-conductive member 4A is arranged. The first housing 51 is a part of the frame 5A and is provided at the bottom of the frame 5A. In the example shown in FIG. 4, the first housing 51 is a portion of the bottom of the frame 5A that protrudes in the axial direction and in the direction orthogonal to the axial direction in the xy plane.

The first housing 51 has a through hole 51A, and the conductive shaft 21 projects out of the frame 5A through the through hole 51A. The maximum inner diameter r1 of the first housing 51 may be larger than the outer diameter of the first bearing 23 (specifically, the first conductive outer ring 23B).

In the xy plane, the maximum width w1 of the through hole 51A of the first housing 51 in the direction orthogonal to the axial direction is larger than the outer diameter of the first bearing 23 (specifically, the first conductive outer ring 23B). big. The first conductive outer ring 23B of the first bearing 23 is not electrically connected to the first housing 51.

Bracket 5B is a conductive bracket. The bracket 5B is made of metal such as iron, for example. The bracket 5B has a second housing 52 in which a second bearing 24 is arranged. The 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 from the flat plate in the axial direction. 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.

The maximum inner diameter r1 of the first housing 51 is larger than the maximum inner diameter r2 of the second housing 52.

As shown in FIG. 4, 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 metal such as iron, for example. 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 placed inside the conductive case 5, but a part or all of the electric circuit 6 may be placed outside the conductive case 5.

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 placed inside the circuit cover 5C. For example, the circuit case 5D is fixed to the bracket 5B. Circuit case 5D is a non-conductive case. The circuit case 5D is made of, for example, non-conductive resin. For example, a concave portion in which the electric circuit 6 is arranged is formed in the circuit case 5D by press molding.

Each of the frame 5A, the bracket 5B, and the circuit cover 5C has a flange 53 forming an outer peripheral edge. The frame 5A, the bracket 5B, and the flange 53 of the circuit cover 5C are fixed to each other with screws, for example. Therefore, the frame 5A, the bracket 5B, and the circuit cover 5C are mechanically coupled and electrically connected to each other. That is, in the example shown in FIG. 1, the conductive housing 5 is partitioned by the bracket 5B into a motor accommodating part 54 in which the rotor 2 and the stator 3 are arranged, and a circuit accommodating part 55 in which the electric circuit 6 is arranged. It is being

<Connector 7>
As shown in FIG. 1, the connector 7 is fixed to the circuit cover 5C. The connector 7 includes, 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.

<First non-conductive member 4A>
As shown in FIG. 1, the first non-conductive member 4A is provided on the load side of the motor 1 with respect to the permanent magnet 22. The first non-conductive member 4A is, for example, a non-conductive resin. The first non-conductive member 4A is fixed to the conductive housing 5 (specifically, the first housing 51 of the frame 5A) by press-fitting or adhesive, for example. The first non-conductive member 4A may be disposed in the conductive housing 5 (specifically, the first housing 51 of the frame 5A) with a clearance fit.

The first non-conductive member 4A has a cylindrical shape. The shape of the first non-conductive member 4A in the xy plane is, for example, an annular shape. In this case, the first non-conductive member 4A has a hollow cylindrical shape, and the first non-conductive member 4A has a through hole. Therefore, the first bearing 23 is arranged inside the first non-conductive member 4A. Therefore, the conductive shaft 21 passes through the first non-conductive member 4A.

Since the first non-conductive member 4A is present between the first conductive outer ring 23B of the first bearing 23 and the first housing 51, the first conductive outer ring of the first bearing 23 23B is electrically insulated from the first housing 51 by the first non-conductive member 4A.

The maximum thickness t1 of the first non-conductive member 4A in the radial direction is determined by the distance from the axis A1 to the outer peripheral surface of the first non-conductive member 4A and the inner peripheral surface of the first non-conductive member 4A from the axis A1. This is the maximum difference between the distance to In other words, the maximum thickness t1 of the first non-conductive member 4A in the radial direction is the maximum thickness in the radial direction.

<Second non-conductive member 4B>
As shown in FIG. 1, the second non-conductive member 4B is provided on the opposite load side of the motor 1 with respect to the permanent magnet 22. The second non-conductive member 4B is, for example, a non-conductive resin. The second non-conductive member 4B is fixed to the conductive shaft 21, for example, by press fitting or adhesive. In this case, the second non-conductive member 4B is molded in advance from a non-conductive resin, and the molded second non-conductive member 4B is fixed to the conductive shaft 21. The second non-conductive member 4B may be integrally molded onto the conductive shaft 21.

The shape of the second non-conductive member 4B is, for example, a cylindrical shape including the bottom. The shape of the second non-conductive member 4B in the xy plane is, for example, an annular shape. In this case, one end of the conductive shaft 21 is inserted inside the second non-conductive member 4B, and is supported in the axial direction by the bottom of the second non-conductive member 4B.

The second non-conductive member 4B is arranged between the second bearing 24 and the conductive shaft 21. Specifically, the second non-conductive member 4B is arranged between the second conductive inner ring 24A of the second bearing 24 and the conductive shaft 21. Since the second non-conductive member 4B exists between the second conductive inner ring 24A of the second bearing 24 and the conductive shaft 21, the second conductive inner ring 24A of the second bearing 24 is electrically insulated from the conductive shaft 21 by the second non-conductive member 4B.

The maximum thickness t2 of the second non-conductive member 4B in the radial direction is determined by the distance from the axis A1 to the outer peripheral surface of the second non-conductive member 4B and the inner peripheral surface of the second non-conductive member 4B from the axis A1. This is the maximum difference between the distance to In other words, the maximum thickness t2 of the second non-conductive member 4B in the radial direction is the maximum thickness in the radial direction.

The maximum thickness t1 of the first non-conductive member 4A in the radial direction is larger than the maximum thickness t2 of the second non-conductive member 4B in the radial direction.

As the material for the first non-conductive member 4A and the second non-conductive member 4B, it is preferable to use a resin having approximately the same coefficient of linear expansion as iron. Examples of materials for forming the first non-conductive member 4A and the second non-conductive member 4B include bulk molding compound resin (BMC resin) as a thermosetting resin. Bulk molding compound resins are thermosetting resins made of unsaturated polyester resins with various additives added. For example, the bulk molding compound resin has the following characteristics.
(1) Productivity is good because the curing time is shorter than that of epoxy resin;
(2) Good balance between material cost and properties;
(3) Molding is possible at low pressure;
(4) High dimensional stability;
(5) High surface hardness and scratch resistance;
(6) It is lighter than metal, has excellent moldability into complex shapes, and has excellent vibration absorption properties.

In this embodiment, bulk molding compound resin is used as the material for forming the first non-conductive member 4A and the second non-conductive member 4B, but bulk molding compound resin other than ceramic or the like is used. Materials may be used.

Variation example.
The motor 1 may be, for example, an embedded permanent magnet motor (IPM motor). In this case, the rotor 2 has a rotor core having at least one magnet insertion hole, and a permanent magnet is arranged in each magnet insertion hole. The rotor core is composed of, for example, a plurality of electromagnetic steel plates laminated in the axial direction.

<Advantages of this embodiment>

According to the present embodiment, the first conductive outer ring 23B is insulated from the conductive housing 5 (specifically, the first housing 51) by the first non-conductive member 4A. The current flowing through the first bearing 23 can be reduced. According to this embodiment, since the second conductive inner ring 24A is insulated from the conductive shaft 21 by the second non-conductive member 4B, it is possible to reduce the current flowing through the second bearing 24. can. Therefore, according to the present embodiment, it is possible to prevent the occurrence of electrolytic corrosion in the first bearing 23 and the second bearing 24, and to reduce vibration and noise in the motor 1. As a result, the performance of the motor 1 can be maintained over a long period of time.

Further, according to the present embodiment, even if the conductive shaft 21 protrudes outside the conductive housing 5 (specifically, the frame 5A), the first conductive outer ring 23B is connected to the first non-conductive It can be easily insulated from the conductive housing 5 (specifically, the first housing 51) by the conductive member 4A.

Furthermore, according to the present embodiment, even if the conductive case 5 (for example, a metal case) is used, the first bearing 23 can be easily insulated from the conductive case 5. This allows the second bearing 24 to be easily insulated from the conductive shaft 21. As a result, the current flowing through the first bearing 23 and the second bearing 24 can be reduced.

The capacitance between the first conductive outer ring 23B of the first bearing 23 and the first housing 51 is referred to as "first capacitance", and the second conductive inner ring 24A of the second bearing 24 is referred to as "first capacitance". The capacitance between the conductive shaft 21 and the conductive shaft 21 will be referred to as "second capacitance". When the maximum thickness t1 of the first non-conductive member 4A in the radial direction is larger than the maximum thickness t2 of the second non-conductive member 4B in the radial direction, the first capacitance and the second capacitance It is possible to reduce the difference between Therefore, the voltage between the first conductive inner ring 23A and the first conductive outer ring 23B of the first bearing 23 that occurs during the rotation of the rotor 2 is referred to as "first bearing voltage", When the voltage generated between the second conductive inner ring 24A and the second conductive outer ring 24B of the second bearing 24 is defined as "second bearing voltage", the first bearing voltage and the second The difference between the bearing voltage and the bearing voltage can be reduced. As a result, the difference in lifespan between the first bearing 23 and the second bearing 24 due to electrolytic corrosion can be reduced, and the performance of the motor 1 can be maintained over a long period of time.

Preferably, the first capacitance is equal to the second capacitance. When the first capacitance is equal to the second capacitance, the difference between the first bearing voltage and the second bearing voltage can be effectively reduced. As a result, the difference in life between the first bearing 23 and the second bearing 24 due to electrolytic corrosion can be effectively reduced.

FIG. 5 is a graph showing the relationship between the maximum thickness [mm] in the radial direction and the capacitance [pF] of each of the first non-conductive member 4A and the second non-conductive member 4B. Hereinafter, with regard to FIG. 5, each of the first capacitance and the second capacitance will also be simply referred to as "capacitance".
As shown in FIG. 5, as the maximum thickness in the radial direction becomes smaller, the capacitance increases rapidly.

In the motor 1, the first capacitance and the second capacitance are preferably 7 pF or less in order to reduce the first bearing voltage and the second bearing voltage. Therefore, as shown in FIG. 5, the maximum thickness t1 in the radial direction of the first non-conductive member 4A is preferably 1.6 mm or more. When the maximum thickness t1 of the first non-conductive member 4A in the radial direction is 1.6 mm or more, the first capacitance of the first non-conductive member 4A can be 7 pF or less. As a result, the first bearing voltage can be reduced, and the current flowing through the first bearing 23 can be reduced.

As shown in FIG. 5, the maximum thickness t2 in the radial direction of the second non-conductive member 4B is preferably 0.5 mm or more. When the maximum thickness t2 of the second non-conductive member 4B in the radial direction is 0.5 mm or more, the second capacitance of the second non-conductive member 4B can be 7 pF or less. As a result, the second bearing voltage can be reduced, and the current flowing through the second bearing 24 can be reduced.

When the relationship between the maximum thickness t1 and the maximum thickness t2 satisfies t1≧1.6mm and t2≧0.5mm, the first bearing voltage and the second bearing voltage can be reduced, and the first bearing 23 and The current flowing through the second bearing 24 can be reduced.

In order to reduce manufacturing costs, the capacitance is preferably 1 pF or more. Therefore, as shown in FIG. 5, the maximum thickness t1 in the radial direction of the first non-conductive member 4A is preferably 16 mm or less. When the maximum thickness t1 of the first non-conductive member 4A in the radial direction is 16 mm or less, manufacturing costs can be suppressed while maintaining the first capacitance at 1 pF or more. As shown in FIG. 5, the maximum thickness t2 in the radial direction of the second non-conductive member 4B is preferably 2.4 mm or less. When the maximum thickness t2 of the second non-conductive member 4B in the radial direction is 2.4 mm or less, manufacturing costs can be suppressed while maintaining the second capacitance at 1 pF or more.

Therefore, it is preferable that the maximum thickness t1 of the first non-conductive member 4A satisfies 1.6 mm≦t1≦16 mm. With this configuration, it is possible to suppress the first bearing voltage while suppressing manufacturing costs. As a result, the current flowing through the first bearing 23 can be reduced. It is preferable that the maximum thickness t2 of the second non-conductive member 4B satisfies 0.5 mm≦t1≦2.4 mm. With this configuration, it is possible to suppress the second bearing voltage while suppressing manufacturing costs. As a result, the current flowing through the second bearing 24 can be reduced.

The relationship between the maximum thickness t1 and the maximum thickness t2 preferably satisfies 1.6 mm≦t1≦16 mm and 0.5 mm≦t2≦2.4 mm. In this case, the maximum thickness t1 and the maximum thickness t2 are adjusted so that t1>t2 is satisfied. With this configuration, it is possible to reduce the current flowing through the first bearing 23 and the second bearing 24 while suppressing manufacturing costs.

FIG. 6 is a graph showing the relationship between the first capacitance and the second capacitance with respect to the ratio t1/t2 when the first capacitance and the second capacitance are equal. be. Hereinafter, with regard to FIG. 6, each of the first capacitance and the second capacitance will also be simply referred to as "capacitance". The ratio t1/t2 is the ratio between the maximum thickness t1 of the first non-conductive member 4A in the radial direction and the maximum thickness t2 of the second non-conductive member 4B in the radial direction.

As shown in Figure 6, when the ratio t1/t2 is 3.1 or more, the capacitance is 7 pF or less, and when the ratio t1/t2 is 6.7 or less, the capacitance is 1 pF or more. be. Therefore, when the first capacitance and the second capacitance are equal and the ratio t1/t2 satisfies 3.1≦(t1/t2)≦6.7, while suppressing the manufacturing cost, The current flowing through the first bearing 23 and the second bearing 24 can be reduced. As a result, it is possible to prevent electrolytic corrosion from occurring in the first bearing 23 and the second bearing 24 while reducing manufacturing costs.

When the outer diameter of the first conductive outer ring 23B is equal to the outer diameter of the second conductive outer ring 24B and the maximum inner diameter r1 of the first housing 51 is larger than the maximum inner diameter r2 of the second housing 52, the first The difference between the capacitance and the second capacitance can be reduced. As a result, the difference in life between the first bearing 23 and the second bearing 24 due to electrolytic corrosion can be reduced.

The first non-conductive member 4A is provided on the load side of the motor 1, and the second non-conductive member 4B is provided on the opposite load side of the motor 1. Therefore, the first bearing 23 can be easily insulated from the conductive housing 5, the second bearing 24 can be easily insulated from the conductive shaft 21, and the productivity of the motor 1 can be increased. can.

The conductive housing 5 includes a cup-shaped frame 5A and a bracket 5B that covers the inside of the cup-shaped frame 5A. In this case, even if the conductive housing 5 is a metal housing, it is possible to prevent electrolytic corrosion of the first bearing 23 and the second bearing 24, and to increase the mechanical strength of the motor 1. I can do it.

When the first non-conductive member 4A is formed of bulk molding compound resin, even if a temperature change occurs within the motor 1, creep in the first non-conductive member 4A can be prevented. As a result, vibration of the first bearing 23 during rotation of the rotor 2 can be prevented.

When the second non-conductive member 4B is formed of bulk molding compound resin, even if a temperature change occurs within the motor 1, creep can be prevented from occurring in the second non-conductive member 4B. As a result, vibration of the second bearing 24 during rotation of the rotor 2 can be prevented.

As explained in the modification, the motor 1 may be an embedded permanent magnet electric motor. When the motor 1 is a permanent magnet embedded electric motor, the rotor 2 has a rotor core having at least one magnet insertion hole, and a permanent magnet is arranged in each magnet insertion hole. In this case, loss in the motor 1 can be reduced, and a small motor 1 with excellent resistance to electrolytic corrosion can be provided.

Embodiment 2.
FIG. 7 is a diagram schematically showing the fan 9 according to the second embodiment.
The fan 9 has blades 91 and a motor 1. The fan 9 is also referred to as a blower. The blade 91 is made of, for example, polypropylene (PP) containing glass fiber. The blades 91 are, for example, a sirocco fan, a propeller fan, a cross flow fan, or a turbo fan.

The motor 1 is the motor 1 according to the first embodiment. The blade 91 is fixed to the 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. Thereby, the fan 9 can blow air.

Since the fan 9 according to the second embodiment includes the motor 1 according to the first embodiment, it can obtain the same advantages as described in the first embodiment. Furthermore, the performance of the fan 9 can be maintained over a long period of time.

Furthermore, since the fan 9 according to the second embodiment includes the motor 1 according to the first embodiment, vibration and noise in the fan 9 can be reduced.

Embodiment 3.
FIG. 8 is a diagram schematically showing 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. Motor 1 is the motor 1 described in Embodiment 1. The vane 81 is fixed to the load side of the conductive shaft 21 of the motor 1 .

The ventilation fan 8 can be used for a wide range of purposes such as residential and commercial use. For example, it is used in residential living rooms, kitchens, bathrooms, and toilets. The blades 81 and at least a portion of the motor 1 are covered by a ventilation fan body 82. The conductive casing 5 of the motor 1 is fixed to the ventilation fan body 82 with screws 83. The ventilation fan body 82 is provided with a power supply connection terminal block 84 and a ground connection terminal 85.

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 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 connected to one end of the power line of the AC power supply. It is connected directly to the other end of my power line. That is, the supply of electric power to the motor 1 is controlled by turning the switch 86 on and off. When the switch 86 is turned on, power is supplied to the motor 1, the blades 81 fixed to the conductive shaft 21 of the motor 1 rotate, and the room is ventilated.

Since the ventilation fan 8 includes the motor 1 according to the first embodiment, it can obtain the same advantages as described in the first embodiment. As a result, the performance of the ventilation fan 8 can be maintained over a long period of time.

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

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

When the conductive casing 5 of the motor 1 is a metal casing, the strength of the motor 1 for holding the rotor 2 is improved. Therefore, if the conductive housing 5 of the motor 1 is a metal housing, a heavy blade such as a large blade or a metal blade can be used as the blade 81.

When the motor 1 is a permanent magnet embedded electric motor, it is possible to provide a small motor 1 with excellent resistance to electrolytic corrosion. Therefore, when the motor 1 is a permanent magnet embedded electric motor, the ventilation fan 8 can be downsized. As a result, the air volume of the ventilation fan 8 can be increased without increasing the size of the ventilation fan body 82.

Embodiment 4.
An air conditioner 10 (also referred to as a refrigeration air conditioner or a refrigeration cycle device) according to a fourth embodiment will be described.
FIG. 9 is a diagram schematically showing the configuration of an air conditioner 10 according to the fourth embodiment.

The air conditioner 10 according to the fourth embodiment includes an indoor unit 11 as a blower (also referred to as a first blower), and an outdoor unit 13 as a blower (also referred to as a second blower) connected to the indoor unit 11. has.

In this embodiment, the air conditioner 10 includes 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.

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

The outdoor unit 13 includes a motor 13a (for example, the motor 1 according to the first embodiment), an air blower 13b, a compressor 14, a heat exchanger (not shown), an air blower 13b, a compressor 14, and a heat exchanger 13b, a compressor 14, and a heat exchanger (not shown). It has a housing 13c that covers the exchanger. The blower section 13b blows air by being driven by the motor 13a. The blowing section 13b has, for example, a blade 13d driven by a motor 13a. For example, the blade 13d is fixed to the shaft of the motor 13a and generates an airflow. The compressor 14 includes a motor 14a (for example, the motor 1 according to the first embodiment), a compression mechanism 14b (for example, a refrigerant circuit) driven by the motor 14a, and a housing 14c that covers the motor 14a and the compression mechanism 14b. have

In the air conditioner 10, at least one of the indoor unit 11 and the outdoor unit 13 includes the motor 1 described in the first embodiment. That is, the indoor unit 11, the outdoor unit 13, or each of the indoor unit 11 and the outdoor unit 13 includes the motor 1 described in the first embodiment. Specifically, the motor 1 described in Embodiment 1 is applied to at least one of the motors 11a and 13a as a drive source for the air blower. That is, the motor 1 described in the first embodiment is applied to the indoor unit 11, the outdoor unit 13, or each of 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.

The air conditioner 10 can perform air conditioning such as a cooling operation in which cold air is blown from the indoor unit 11 and a heating operation in which warm air is blown. In the indoor unit 11, the motor 11a is a drive source for driving the ventilation section 11b. The blowing section 11b can blow the conditioned air.

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

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, so that the same advantages as those described in the first embodiment can be obtained. I can do it. As a result, the performance of the air conditioner 10 can be maintained over a long period of time.

Furthermore, when the motor 1 according to the first embodiment is used as a drive source for a blower (for example, the indoor unit 11), the same advantages as described in the first embodiment can be obtained. As a result, the performance of the blower is maintained over a long period of time. The blower having the motor 1 according to the first embodiment and the blades (for example, the blades 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.

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

In addition to the air conditioner 10, the motor 1 described in the first embodiment can be mounted on a device having a drive source, such as a ventilation fan, a home appliance, or a machine tool.

The features of each embodiment and the features of each modification described above can be combined with each other.

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

Claims (12)

stator and
a rotor that is disposed inside the stator and has a conductive shaft and first and second bearings that rotatably support the conductive shaft;
a first non-conductive member;
a second non-conductive member disposed between the second bearing and the conductive shaft;
a conductive housing having a first housing in which the first non-conductive member is disposed, a second housing in which the second bearing is disposed, and in which the stator and rotor are disposed; Prepare,
The first bearing has a first conductive inner ring and a first conductive outer ring,
The second bearing has a second conductive inner ring and a second conductive outer ring,
the first conductive outer ring is insulated from the first housing by the first non-conductive member;
the first conductive inner ring is in contact with the conductive shaft;
the second conductive inner ring is insulated from the conductive shaft by the second non-conductive member;
The second electrically conductive outer ring is in contact with the second housing. The outer diameter of the first conductive outer ring is equal to the outer diameter of the second conductive outer ring,
The motor according to claim 1, wherein a maximum inner diameter of the first housing is larger than a maximum inner diameter of the second housing. The motor according to claim 1 or 2, wherein the maximum thickness of the first non-conductive member in the radial direction is greater than the maximum thickness of the second non-conductive member in the radial direction. The motor according to claim 3, wherein the maximum thickness of the first non-conductive member is 1.6 mm or more and 16 mm or less. The motor according to claim 3, wherein the maximum thickness of the second non-conductive member is 0.5 mm or more and 2.4 mm or less. A claim that satisfies 3.1≦(t1/t2)≦6.7, where the maximum thickness of the first non-conductive member is t1 and the maximum thickness of the second non-conductive member is t2. The motor according to item 3. The first non-conductive member is provided on the load side of the motor,
The motor according to any one of claims 1 to 6, wherein the second non-conductive member is provided on the opposite load side of the motor. The conductive casing includes:
a cup-shaped frame including the first housing and in which the stator is arranged;
The motor according to any one of claims 1 to 7, further comprising a bracket that includes the second housing and covers the inside of the cup-shaped frame. The rotor is
a rotor core having a magnet insertion hole;
The motor according to any one of claims 1 to 8, further comprising a permanent magnet disposed in the magnet insertion hole. feathers and
A fan comprising: the motor according to any one of claims 1 to 9, which rotates the blades. feathers and
A ventilation fan comprising: the motor according to any one of claims 1 to 9, which rotates the blades. indoor unit and
an outdoor unit connected to the indoor unit;
The indoor unit, the outdoor unit, or each of the indoor unit and the outdoor unit includes the motor according to claim 1 . An air conditioner.

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