WO2022259394A1

WO2022259394A1 - Motor, fan, ventilator, and air conditioner

Info

Publication number: WO2022259394A1
Application number: PCT/JP2021/021838
Authority: WO
Inventors: 和彦馬場; 淳一尾▲崎▼
Original assignee: 三菱電機株式会社
Priority date: 2021-06-09
Filing date: 2021-06-09
Publication date: 2022-12-15
Also published as: JPWO2022259394A1; JP7450817B2

Abstract

This motor (1) has a rotor (2), a stator (3), a first non-conductive member (4A), a second non-conductive member (4B), and a conductive case (5). A first conductive outer race (23B) of a first bearing (23) is insulated from a first housing (51) of the conductive case (5) by the first non-conductive member (4A). A second conductive inner race (24A) of a second bearing (24) is insulated from a conductive shaft (21) of the rotor (2) by the second non-conductive member (4B). A first conductive inner race (23A) of the first bearing (23) is in contact with the conductive shaft (21). A second conductive outer race (24B) of the second bearing (24) is in contact with a second housing (52) of the conductive case (5).

Description

Motors, fans, ventilators, and air conditioners

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

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

WO2019/167233

Generally, if the housing in which the first of the pair of bearings is located is electrically conductive, the first bearing is electrically connected to the housing and the second of the pair of bearings is fixed. A second bearing is electrically connected to the shaft if the shaft on which it is mounted is electrically conductive. In this case, the voltage between the inner ring and the outer ring of each bearing increases, and the current flowing through the bearing increases. As a result, electrolytic corrosion occurs in the bearings, increasing vibration and noise in the motor.

The purpose of the present disclosure is to reduce the current flowing through the bearing.

The motor of the present disclosure is
a stator;
a rotor disposed inside the stator and having an electrically conductive shaft and first and second bearings rotatably supporting the electrically 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 arranged, a second housing in which the second bearing is arranged, and a conductive housing in which the stator and the rotor are arranged; prepared,
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 electrically 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 contacts 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 includes:
feathers and
and the motor that rotates the blade.
An air conditioner according to another aspect of the present disclosure includes
indoor unit and
and an outdoor unit connected to the indoor unit,
Each of the indoor unit, the outdoor unit, or the indoor unit and the outdoor unit has the motor.

According to the present disclosure, the current flowing through the bearing can be reduced.

1 is a cross-sectional view schematically showing a motor according to Embodiment 1; FIG. It is a perspective view which shows a stator roughly. It is a circuit diagram which shows an example of an electric circuit. 2 is a cross-sectional view showing the conductive housing shown in FIG. 1; FIG. It is a graph which shows the relationship between the maximum thickness [mm] in the radial direction of each of the first non-conductive member and the second non-conductive member and the capacitance [pF]. The first capacitance and the second capacitance for the ratio t1/t2 when the first capacitance of the first non-conducting member and the second capacitance of the second non-conducting member are equal It is a graph which shows the relationship with each of electrostatic capacitance. FIG. 6 is a diagram schematically showing a fan according to Embodiment 2; FIG. FIG. 11 is a diagram schematically showing a ventilation fan according to Embodiment 3; FIG. 10 is a diagram schematically showing the configuration of an air conditioner according to Embodiment 4;

Embodiment 1.
A motor 1 according to Embodiment 1 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 orthogonal to the z-axis direction. , the y-axis direction (y-axis) indicates a direction orthogonal to both the z-axis direction and the x-axis direction. The axis A<b>1 is the center of rotation 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 the radial direction of the rotor 2, the stator 3, or the stator core 31, and is the 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 "circumferential direction".

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

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

As shown in FIG. 1, the stator 3 has a stator core 31, at least one insulator 32, at least one coil 33, and at least one conducting pin 34. Each coil 33 is wound around the insulator 32 . The stator 3 is press-fitted into the frame 5A of the conductive housing 5. As shown in FIG.

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

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

Each insulator 32 is provided on the tooth 31B. Each insulator 32 is, 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, insulator 32 is molded integrally with 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 conduction pin 34 is fixed to the insulator 32, for example. Each conducting pin 34 electrically connects the coil 33 and the electric circuit 6 . Specifically, each conductive pin 34 electrically connects the coil 33 and the switching circuit 64 b of the inverter circuit 64 of the electric circuit 6 .

<Electric 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 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 .

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

The filter circuit 62 has 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 has 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 the rectifier circuit 63a having a diode bridge, and is thereby converted to direct current. The direct current is accumulated in the smoothing capacitor 63b. In the smoothing capacitor 63b, a direct current (for example, DC140V or DC280V) required by the switching circuit 64b is generated. The switching power supply 63c uses the direct current generated in the smoothing capacitor 63b to generate the control power (for example, DC 15V) required by the drive circuit 64a.

The inverter circuit 64 has 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 and the negative bus. The positive bus line is connected to the positive terminal of the smoothing capacitor 63b, and the negative bus line is connected to the negative terminal of the smoothing capacitor 63b. The three transistors on the positive bus line side are upper arm transistors. The three transistors on the negative bus line side are lower arm transistors. Each switching element is connected in antiparallel to a freewheeling diode. A connection terminal of each of the upper arm transistor and the lower arm transistor constitutes an output terminal and is connected to the U phase, V phase, or W phase of the coil 33 .

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

In the present embodiment, for example, 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 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 PWM signals 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 has a conductive shaft 21 , permanent magnets 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 (that is, axis A1).

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

The entire permanent magnet 22 may be a plastic magnet, or part of the permanent magnet 22 may be a plastic magnet. When a 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 the 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.

The permanent magnet 22 is fixed to the conductive shaft 21. A permanent magnet 22 is positioned between a first bearing 23 and a second bearing 24 . Conductive shaft 21 is rotatably supported by first bearing 23 and 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 anti-load side of the motor 1 with respect to the permanent magnet 22 . A second bearing 24 rotatably supports the non-load side of the conductive shaft 21 .

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 . Since the anti-load side of the conductive shaft 21 does not protrude outside the conductive housing 5, the second non-conductive member 4B can be easily provided at the end of the conductive shaft 21 on the anti-load side by integral molding. be able to.

In the present 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.

In the example shown in FIG. 1, the outer diameter of the end portion of the conductive shaft 21 on the non-load side is smaller than the outer diameter of the other portion of the conductive shaft 21 . A second non-conductive member 4B covers the end of the conductive shaft 21 on the non-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 electrically conductive. 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. As shown in FIG. The first conductive inner ring 23A is fixed to the conductive shaft 21 by, for example, 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 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 isolated 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, for example, press fitting or adhesive. The first bearing 23 (specifically, the first conductive outer ring 23B) may be arranged on 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 positioned between second conductive inner ring 24A and second conductive outer ring 24B. Each ball 24C is electrically conductive. 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 by, for example, press fitting 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 isolated 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 substantially 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. It is Even if the second bearing 24 (specifically, the second conductive outer ring 24B) is arranged 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 and 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) to apply preload to the second bearing 24 in the axial direction. Since the preload in the axial direction is applied to the first bearing 23 and the second bearing 24 by the preload spring, rattling of the

balls

23C and 24C during the rotation of the rotor 2 can be prevented.

In this embodiment, the size of the first bearing 23 is equal to the size of the second bearing 24. Therefore, the outer diameter (ie, diameter) of first conductive outer ring 23B is equal to the outer diameter (ie, diameter) of 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 having an outer diameter of 22 mm, an inner diameter of 8 mm, and a width of 7 mm. Although the size of the first bearing 23 is equal to the size of the second bearing 24 in this embodiment, 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 cross-sectional view showing the conductive housing 5 shown in FIG.
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 a conductive housing 5 (specifically, a frame 5A in FIG. 4). The conductive housing 5 is made of metal such as iron, for example.

The 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 the first non-conductive member 4A is arranged. The first housing 51 is 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 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 protrudes 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. First conductive outer ring 23B of first bearing 23 is not electrically connected to first housing 51 .

The bracket 5B is a conductive bracket. The bracket 5B is made of metal such as iron, for example. Bracket 5B has a second housing 52 in which 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 part of the bracket 5B that protrudes axially from the flat plate. In the example shown in FIG. 1, the second conductive outer ring 24B of the second bearing 24 contacts the second housing 52. In the example shown in FIG.

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 have a circuit cover 5C. 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. As shown in FIG. Specifically, the circuit cover 5C covers the electric circuit 6 together with the bracket 5B. Although the electric circuit 6 is arranged inside the conductive housing 5 in the present embodiment, part or all of the electric circuit 6 may be arranged outside the conductive housing 5 .

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

Each of the frame 5A, bracket 5B, and circuit cover 5C has a flange 53 forming an outer peripheral edge. The frame 5A, the bracket 5B, and the flanges 53 of the circuit cover 5C are fixed to each other with screws, for example. Therefore, the frame 5A, bracket 5B, and 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 housing portion 54 in which the rotor 2 and the stator 3 are arranged, and a circuit housing portion 55 in which the electric circuit 6 is arranged. It is

<Connector 7>
As shown in FIG. 1, connector 7 is fixed to circuit cover 5C. The connector 7 has, for example, wiring and a non-conductive cover covering 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. As shown in FIG. The first non-conductive member 4A is, for example, 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, for example, press fitting or adhesive. The first non-conductive member 4A may be arranged in the conductive housing 5 (specifically, the first housing 51 of the frame 5A) with a clearance fit.

The shape of the first non-conductive member 4A is cylindrical. The shape of the first non-conductive member 4A in the xy plane is, for example, an annular shape. In this case, the shape of the first non-conductive member 4A is 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 exists 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 first housing 51 by first non-conductive member 4A.

The maximum thickness t1 of the first non-conductive member 4A in the radial direction is 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. is the maximum difference from 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 non-load side of the motor 1 with respect to the permanent magnet 22. As shown in FIG. The second non-conductive member 4B is, for example, non-conductive resin. The second non-conductive member 4B is fixed to the conductive shaft 21 by, for example, 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. FIG. The second non-conductive member 4B may be integrally formed with the conductive shaft 21 .

The shape of the second non-conductive member 4B is, for example, a cylindrical shape including a 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 axially supported 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 a second non-conductive member 4B.

The maximum thickness t2 of the second non-conductive member 4B in the radial direction is 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. is the maximum difference from 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 greater than the maximum thickness t2 of the second non-conductive member 4B in the radial direction.

As the material of 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. Materials for forming the first non-conductive member 4A and the second non-conductive member 4B include, for example, bulk molding compound resin (BMC resin) as a thermosetting resin. Bulk molding compound resins are thermosetting resins in which various additives are added to unsaturated polyester resins. The bulk molding compound resin has, for example, the following characteristics.
(1) Productivity is good because curing time is shorter than that of epoxy resin;
(2) a good balance between material cost and properties;
(3) Molding at low pressure is possible;
(4) high dimensional stability;
(5) High surface hardness and scratch resistance;
(6) It is lighter than metal, has excellent formability into complicated shapes, and has excellent vibration absorption.

In the present embodiment, a bulk molding compound resin is used as a material for forming the first non-conductive member 4A and the second non-conductive member 4B. material may be used.

Modification.
The motor 1 may be, for example, an embedded permanent magnet motor (IPM motor). In this case, the rotor 2 has a rotor core with 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 magnetic steel sheets laminated in the axial direction.

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, the second conductive inner ring 24A is insulated from the conductive shaft 21 by the second non-conductive member 4B, so the current flowing through the second bearing 24 can be reduced. can. Therefore, according to the present embodiment, the occurrence of electrolytic corrosion in the first bearing 23 and the second bearing 24 can be prevented, and vibration and noise in the motor 1 can be reduced. As a result, the performance of the motor 1 can be maintained over a long period of time.

Furthermore, 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 shaft. 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 when the conductive housing 5 (for example, a metal housing) is used, the first bearing 23 can be easily insulated from the conductive housing 5. , and the second bearing 24 can 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 defined as "first capacitance", and the second conductive inner ring 24A of the second bearing 24 and the conductive shaft 21 is defined as a "second capacitance". When the maximum thickness t1 of the first non-conductive member 4A in the radial direction is greater than the maximum thickness t2 of the second non-conductive member 4B in the radial direction, the first capacitance and the second capacitance difference can be reduced. Therefore, the voltage generated between the first conductive inner ring 23A and the first conductive outer ring 23B of the first bearing 23 during rotation of the rotor 2 is defined 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 can reduce the difference between the bearing voltage of As a result, the difference in service life 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.

The first capacitance is preferably 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 service 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 reference to FIG. 5, each of the first capacitance and the second capacitance is also simply referred to as "capacitance".
As shown in FIG. 5, the capacitance increases sharply as the maximum thickness in the radial direction decreases.

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 first non-conductive member 4A preferably has a maximum radial thickness t1 of 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 second non-conductive member 4B preferably has a maximum radial thickness t2 of 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≧1.6 mm and t2≧0.5 mm, 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 first non-conductive member 4A preferably has a maximum radial thickness t1 of 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 reduced while maintaining the first capacitance at 1 pF or more. As shown in FIG. 5, the second non-conductive member 4B preferably has a maximum radial thickness t2 of 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 reduced while maintaining the second capacitance at 1 pF or more.

Therefore, the maximum thickness t1 of the first non-conductive member 4A preferably satisfies 1.6mm≤t1≤16mm. 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. A maximum thickness t2 of the second non-conductive member 4B preferably satisfies 0.5 mm≦t1≦2.4 mm. With this configuration, it is possible to suppress the second bearing voltage while suppressing the manufacturing cost. 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 as to satisfy t1>t2. With this configuration, the current flowing through the first bearing 23 and the second bearing 24 can be reduced while suppressing the manufacturing cost.

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 reference to FIG. 6, each of the first capacitance and the second capacitance is also 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 FIG. 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, the occurrence of electrolytic corrosion in the first bearing 23 and the second bearing 24 can be prevented while suppressing 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 greater than the maximum inner diameter r2 of the second housing 52, the first and the second capacitance can be reduced. As a result, the difference in service 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 non-load side of the motor 1. Therefore, the first bearing 23 can be easily isolated from the conductive housing 5, the second bearing 24 can be easily isolated from the conductive shaft 21, and the productivity of the motor 1 can be improved. can.

The conductive housing 5 has 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, electrolytic corrosion of the first bearing 23 and the second bearing 24 can be prevented, and the mechanical strength of the motor 1 can be increased. can be done.

When the first non-conductive member 4A is formed of bulk molding compound resin, even if temperature changes occur in the motor 1, the occurrence of 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 temperature changes occur in the motor 1, the second non-conductive member 4B can be prevented from creeping. As a result, vibration of the second bearing 24 during rotation of the rotor 2 can be prevented.

As described in the modified example, the motor 1 may be a permanent magnet embedded electric motor. When the motor 1 is an embedded permanent magnet type 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, the loss in the motor 1 can be reduced, and the compact motor 1 with excellent resistance to electrolytic corrosion can be provided.

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

The motor 1 is the motor 1 according to the first embodiment. Blade 91 is fixed to the shaft of motor 1 . A motor 1 drives the blades 91 . Specifically, the motor 1 rotates the vane 91 . When the motor 1 is driven, the blades 91 are rotated to generate an airflow. Thereby, the fan 9 can blow air.

Since the fan 9 according to Embodiment 2 has the motor 1 according to Embodiment 1, the same advantages as those described in Embodiment 1 can be obtained. Furthermore, the performance of the fan 9 can be maintained for a long period of time.

Furthermore, since the fan 9 according to Embodiment 2 has the motor 1 according to Embodiment 1, vibration and noise in the fan 9 can be reduced.

Embodiment 3.
FIG. 8 is a diagram schematically showing the ventilation fan 8 according to Embodiment 3. As shown in FIG.
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. A vane 81 is fixed to the load side of the electrically conductive shaft 21 of the motor 1 .

The ventilation fan 8 can be used for a wide range of purposes such as residential use and business use. For example, it is used in residential living rooms, kitchens, bathrooms and toilets. The blades 81 and at least part of the motor 1 are covered with a fan body 82 . The conductive housing 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 connection terminal block 84 and a ground connection terminal 85 .

The connector 7 of the motor 1 is connected to the power 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 AC power supply line through a switch 86, and the other end of the external connection terminals of the power supply connection terminal block 84 is connected to the AC power supply. It is directly connected to the other end of our power line. That is, the power supply 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 vanes 81 fixed to the conductive shaft 21 of the motor 1 rotate, and the room is ventilated.

Since the ventilation fan 8 has the motor 1 according to Embodiment 1, the same advantages as those described in Embodiment 1 can be obtained. As a result, the performance of the ventilation fan 8 can be maintained for a long period of time.

Furthermore, since the ventilation fan 8 has the motor 1 according to Embodiment 1, 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. As shown in FIG. The electric circuit 6 of the motor 1 is arranged outside the 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 susceptible to temperature and humidity inside the ventilator body 82 . Therefore, stable performance of the ventilation fan 8 can be maintained for 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 housing 5 of the motor 1 is a metal housing, 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, heavy blades such as large blades and metal blades can be applied to the blades 81 .

If the motor 1 is an embedded permanent magnet type electric motor, it is possible to provide a compact motor 1 with excellent resistance to electrolytic corrosion. Therefore, if the motor 1 is a permanent magnet embedded electric motor, the ventilation fan 8 can be made smaller. 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 Embodiment 4 will be described.
FIG. 9 is a diagram schematically showing the configuration of air conditioner 10 according to Embodiment 4. As shown in FIG.

An air conditioner 10 according to Embodiment 4 includes an indoor unit 11 as a fan (also referred to as a first fan) and an outdoor unit 13 as a fan (also referred to as a second fan) connected to the indoor unit 11. have

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 .

The indoor unit 11 has a motor 11a (for example, the motor 1 according to Embodiment 1), a blower section 11b that blows air by being driven by the motor 11a, and a housing 11c that covers the motor 11a and the blower section 11b. . The air blower 11b has, for example, blades 11d driven by a motor 11a. For example, vanes 11d are fixed to the shaft of motor 11a and generate airflow.

The outdoor unit 13 includes a motor 13a (for example, the motor 1 according to Embodiment 1), an air blower 13b, a compressor 14, a heat exchanger (not shown), an air blower 13b, a compressor 14, and a heat exchanger. and a housing 13c covering the exchanger. The air blower 13b blows air by being driven by the motor 13a. The air blower 13b has, for example, blades 13d driven by a motor 13a. For example, the vanes 13d are fixed to the shaft of the motor 13a and generate the airflow. The compressor 14 includes a motor 14a (for example, the motor 1 according to Embodiment 1), 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 has the motor 1 described in the first embodiment. That is, each of the indoor unit 11, the outdoor unit 13, or the indoor unit 11 and the outdoor unit 13 has the motor 1 described in the first embodiment. Specifically, the motor 1 described in the first embodiment is applied to at least one of the

motors

11a and 13a as the driving source of the air blower. That is, the motor 1 described in Embodiment 1 is applied to each of the indoor unit 11 and the outdoor unit 13, or the indoor unit 11 and the outdoor unit 13. Motor 1 described in the first embodiment may be applied to motor 14 a of compressor 14 .

The air conditioner 10 can perform air conditioning, for example, 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 air blower 11b. The air blower 11b can blow the adjusted air.

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

In the air conditioner 10 according to Embodiment 4, the motor 1 described in Embodiment 1 is applied to at least one of the

motors

11a and 13a, so the same advantages as those described in Embodiment 1 can be obtained. can be done. As a result, the performance of the air conditioner 10 can be maintained for a long period of time.

Furthermore, when the motor 1 according to Embodiment 1 is used as the drive source for the blower (for example, the indoor unit 11), the same advantages as those described in Embodiment 1 can be obtained. As a result, the performance of the blower is maintained over a long period of time. The fan having the motor 1 according to Embodiment 1 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 Embodiment 1 is used as the drive source for the compressor 14, the same advantages as those described in Embodiment 1 can be obtained. As a result, the performance of the compressor 14 can be maintained for a long period of time.

The motor 1 described in Embodiment 1 can be installed in equipment having a drive source, such as a ventilation fan, a home appliance, or a machine tool, in addition to the air conditioner 10 .

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 housing, 5A frame, 5B bracket, 6 electric circuit, 7 Connector, 8: Ventilation fan, 9: Fan, 10: Air conditioner, 11: Indoor unit, 12: Refrigerant pipe, 13: Outdoor unit, 21: Conductive shaft, 22: Permanent magnet, 23: First bearing, 23A: First conductive inner ring, 23B: Second 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 second 2 housings, 81, 91 vanes.

Claims

a stator;
a rotor disposed inside the stator and having an electrically conductive shaft and first and second bearings rotatably supporting the electrically 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 arranged, a second housing in which the second bearing is arranged, and a conductive housing in which the stator and the rotor are arranged; prepared,
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 electrically 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. Motor.
The outer diameter of the first conductive outer ring is equal to the outer diameter of the second conductive outer ring,
2. The motor according to claim 1, wherein the maximum inner diameter of said first housing is larger than the maximum inner diameter of said 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.
3.1≤(t1/t2)≤6.7, where t1 is the maximum thickness of the first non-conductive member and t2 is the maximum thickness of the second non-conductive member. Item 4. 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 anti-load side of the motor.
The conductive housing is
a cup-shaped frame including the first housing and having the stator disposed thereon;
A motor according to any one of claims 1 to 7, comprising: a bracket containing the second housing and covering the interior 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 permanent magnets arranged in the magnet insertion holes.
feathers and
and the motor according to any one of claims 1 to 9, which rotates the blades.
feathers and
and the motor according to any one of claims 1 to 9, which rotates the blades.
indoor unit and
and an outdoor unit connected to the indoor unit,
Each of the indoor unit, the outdoor unit, or the indoor unit and the outdoor unit has the motor according to any one of claims 1 to 9. An air conditioner.