JP5490201B2 - Electric motor, air conditioner incorporating the electric motor, and method for manufacturing the electric motor - Google Patents

Description

  The present invention relates to an electric motor, an air conditioner incorporating the electric motor, and a method for manufacturing the electric motor.

  In recent years, electric motors are increasingly used in a system driven by an inverter of a pulse width modulation (Pulse Width Modulation) method (hereinafter referred to as a PWM method as appropriate). In such a PWM inverter-driven electric motor, the neutral point potential of the winding does not become zero, so that a potential difference (hereinafter referred to as a shaft voltage) occurs between the outer ring and the inner ring of the bearing. This shaft voltage contains high-frequency components due to switching of the inverter. When the shaft voltage reaches the breakdown voltage of the oil film inside the bearing, a current (hereinafter referred to as shaft current) flows inside the bearing, and the electric corrosion occurs inside the bearing. Will occur. When electrolytic corrosion progresses, a wave-like wear phenomenon occurs in the bearing inner ring, the bearing outer ring, or the bearing rolling element, and abnormal noise resulting from this wear phenomenon is one of the main causes of problems in the motor.

  In conventional motors, the current flowing inside the bearing is reduced by electrically connecting the bearing inner ring and the outer ring, and the occurrence of wave wear in the bearing inner ring, bearing outer ring or bearing rolling element is suppressed, resulting in the wave wear phenomenon. The occurrence of abnormal noise is suppressed (for example, see Patent Document 1 below).

JP-A-9-291944

  However, since the electric motor shown in Patent Document 1 uses a configuration in which a movable part that operates with rotation and a non-movable part are in contact with each other when electrically connecting a bearing inner ring and an outer ring. During use, there is a problem that the bearing inner ring and the outer ring are not electrically connected due to wear, and the shaft current suppression effect is reduced.

  The present invention has been made in view of the above, and includes an electric motor capable of suppressing electric corrosion of a bearing even during long-term use, an air conditioner incorporating the electric motor, and a method for manufacturing the electric motor. The purpose is to obtain.

  In order to solve the above-described problems and achieve the object, the present invention provides a stator having an annular stator core and an outer periphery of a rotating shaft that is disposed inside the stator and faces the stator core. A rotor having a permanent magnet disposed on the side, a first bearing that rotatably supports one end of the rotating shaft, a second bearing that rotatably supports the other end of the rotating shaft, and the rotation A drive circuit board that is disposed substantially perpendicular to the axial direction between the stator and the first bearing in the axial direction of the shaft, and on which a circuit for driving the rotor to rotate is mounted; A conductive member formed in a plate shape, located between the first bearing and the permanent magnet in the axial direction of the rotary shaft, and electrically connected to the outer ring of the first bearing; The first fixed to the stator without contacting the rotating shaft A constant disk-shaped conductor and a conductive member formed in the shape of an annular plate, and positioned between the first fixed disk-shaped conductor and the permanent magnet in the axial direction of the rotating shaft; A first rotating disk-shaped conductor installed on the rotating shaft and an annular plate-like shape are arranged in the vicinity of the first fixed disk-shaped conductor without contacting the fixed disk-shaped conductor. It is made of a conductive member, is located between the second bearing and the permanent magnet in the axial direction of the rotating shaft, is electrically connected to the outer ring of the second bearing, and is in contact with the rotating shaft A second fixed disk-shaped conductor that is fixed to the stator without being formed, and a conductive member formed in an annular plate shape, and the second fixed disk-shaped conductor and the Located between the permanent magnet and the second fixed disk-shaped conductor. The second rotating disk-shaped conductor installed on the rotating shaft, the stator core and the drive circuit board are integrally formed so as to be disposed in the vicinity of the second fixed disk-shaped conductor And a mold resin provided with a recess formed therein so as to be able to accommodate the rotor, and an inner periphery of the mold resin so as to close the opening of the recess, and the second resin And a conductive bracket in which an outer ring of the bearing is fitted inside.

  According to the present invention, the fixed disk-shaped conductor and the rotating disk-shaped conductor are disposed so as to be in a conductive state at a high frequency without being in contact with each other. There is an effect that the electrolytic corrosion of the bearing can be suppressed even during long-term use without contact with the part.

1 is a side cross-sectional view of an electric motor according to Embodiment 1. FIG. FIG. 2 is a diagram schematically showing the rotor assembly. FIG. 3 is a diagram showing a cross section of the rotating shaft and the board-side fixed disk-shaped conductor, or a cross section of the rotating shaft and the non-board-side fixed disk-shaped conductor. FIG. 4 is a diagram illustrating a manufacturing process of the electric motor according to the second embodiment. FIG. 5 is a configuration diagram of an air conditioner according to Embodiment 3.

  DESCRIPTION OF EMBODIMENTS Embodiments of an electric motor according to the present invention, an air conditioner incorporating the electric motor, and a method for manufacturing the electric motor will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a side cross-sectional view of an electric motor 100 according to an embodiment of the present invention, and FIG. 2 is a diagram schematically showing a main part of the electric motor 100. FIG. 3 is a diagram showing a cross section of the rotary shaft 10 and the board-side fixed disk-shaped conductor 17a-1, or a cross section of the rotary shaft 10 and the non-board-side fixed disk-shaped conductor 17b-1. An electric motor 100 shown in FIG. 1 includes, as main components, a stator 6, a drive circuit board 4, a rotor 14, a board-side bearing 15a (first bearing), and an anti-board-side bearing 15b (second board). ), A board-side fixed disk-shaped conductor 17a-1 (first fixed disk-shaped conductor), a board-side rotating disk-shaped conductor 17a-2 (first rotating disk-shaped conductor), and an anti-board-side fixed disk A conductor 17b-1 (second fixed disk-shaped conductor), an anti-substrate-side rotating disk-shaped conductor 17b-2 (second rotating disk-shaped conductor), a mold resin 2, and a conductive bracket 20. Configured. The electric motor 100 is a brushless DC motor driven by an inverter, for example. In FIG. 1, only the left half of the configuration of the electric motor 100 centering on the rotating shaft 10 is shown, but the same applies to the right half.

  The stator assembly 3 is an assembly of the stator 6 and the drive circuit board 4 among the components of the electric motor 100. The rotor assembly 15 is an assembly of the rotor 14, the board-side bearing 15 a, and the non-board-side bearing 15 b among the components of the electric motor 100.

  The mold stator 1 is formed in a substantially cylindrical shape with the rotating shaft 10 as the center, and includes a stator assembly 3 and a mold resin 2. The stator assembly 3 is integrally formed with the mold resin 2. The stator assembly 3 includes a drive circuit board 4 and the like. However, since the drive circuit board 4 and the like have a weak structure, low pressure molding is desirable. To form the drive circuit board 4 and the like integrally, for example, a thermosetting resin (mold resin 2) such as unsaturated polyester resin is used. ) Is used.

  The drive circuit board 4 and the stator 6 are mechanically coupled by the mold resin 2 and are integrally formed. The mold resin 2 constitutes the outline of the electric motor 100, and constitutes the bearing housing portion 2b on the substrate side surface (upper side in FIG. 1) of the mold stator 1. The bearing housing portion 2b surrounds and supports the outer ring 15a-1 of the board side bearing 15a.

  The mold resin 2 accommodates the rotor assembly 15 into the mold stator 1 through an opening provided on the surface (lower side in FIG. 1) opposite to the load (fan or the like) side surface of the mold resin 2. For example, a mortar-shaped recess 19 that is formed is provided. The opening is a portion where the conductive bracket 20 is provided in FIG. The conductive bracket 20 is manufactured, for example, by pressing a conductive metal.

  The stator 6 includes a winding 7, a stator core 8, and an insulator 9. The stator core 8 is manufactured by punching a magnetic steel sheet having a thickness of, for example, about 0.1 to 0.7 mm into a strip shape, and laminating by caulking, welding, adhesion, or the like. The stator core 8 is annular and includes a plurality of teeth (not shown) on the inner peripheral side, and an insulator 9 is applied to the teeth. The insulator 9 is molded integrally with or separately from the stator core 8 using a thermoplastic resin such as PBT (polybutylene terephthalate). Concentrated windings 7 are wound around the teeth to which the insulator 9 is applied. A plurality of concentrated windings 7 are connected to form, for example, a three-phase single Y-connection winding. However, distributed winding may be used.

  The drive circuit board 4 is built in the mold stator 1 in the vicinity of the board-side bearing 15a held by the bearing housing portion 2b. Specifically, the drive circuit board 4 is disposed between the board-side bearing 15a and the stator 6 in the axial direction of the rotary shaft 10, and is disposed substantially perpendicular to the axial direction. A power conversion circuit (not shown) for driving the electric motor 100 is mounted on the drive circuit board 4, and the power conversion circuit includes an inverter circuit and the like. The inverter circuit converts AC power for rotationally driving the rotor 14 from a DC power source. The voltage from the inverter circuit is applied to the winding 7 via a terminal (not shown) that electrically connects the drive circuit board 4 and the winding 7. In addition to the inverter circuit, the drive circuit board 4 includes, for example, a Hall element that detects the rotation speed or the rotation position of the rotor 14 based on a change in magnetic flux density generated by the position detection magnet 11, and the drive circuit board 4. Although connection leads and the like for electrically connecting an external circuit (not shown) of the electric motor 100 are mounted, these are not shown in FIG.

  A hole for inserting the rotor assembly 15 (rotating shaft 10) is provided at the center of the drive circuit board 4.

  The rotor 14 has a rotating shaft 10, an annular rotor insulating portion 12 provided on the outer peripheral portion of the rotating shaft 10, and is provided on the outer peripheral side of the rotor insulating portion 12 so as to face the stator core 8. A rotor magnet 13 which is an arranged permanent magnet, a position detection magnet 11 provided between the rotor magnet 13 and the drive circuit board 4 in the axial direction of the rotary shaft 10, and a resin portion for integrally molding these. 18. The resin portion 18 is formed on the outer peripheral surface of the rotary shaft 10 around the knurl 10 a provided on the rotary shaft 10. The rotor 14 is installed so as to be rotatable about the rotating shaft 10, obtains a rotating force by a rotating magnetic field from the stator 6, transmits torque to the rotating shaft 10, and loads (not shown) provided on the rotating shaft 10 (not shown). For example, an air conditioner indoor unit and / or a fan built in an outdoor unit) is driven.

  The rotor insulating portion 12 is provided to insulate the rotating shaft 10 and the rotor magnet 13 and insulate the rotating shaft 10 and the stator core 8 from each other. The rotor magnet 13, the rotating shaft 10, and the position detecting magnet 11 are integrally formed by a rotor insulating portion 12 injected by, for example, a vertical molding machine. For the rotor insulating portion 12, for example, a thermoplastic resin such as PBT (polybutylene terephthalate) or PPS (polyphenylene sulfide) is used, and those in which a glass filler is blended with these resins are also suitable. A dielectric layer is formed on the rotor insulating portion 12. As the rotor magnet 13, a resin magnet formed by mixing a magnetic material with a thermoplastic resin, a rare earth magnet (neodymium, samarium iron), a ferrite sintered magnet, or the like is used.

  In the axial direction of the rotary shaft 10, a substrate side bearing 15a is attached to the load side (upper side in FIG. 1) of the rotary shaft 10 to which a fan or the like is attached, and the rotary shaft on the opposite side (lower side in FIG. 1) 10 is attached with a non-substrate-side bearing 15b. The rotating shaft 10 is rotatably supported by the substrate side bearing 15a and the non-substrate side bearing 15b.

  The board-side bearing 15a is a ball bearing, and is disposed between the inner and outer rings, an inner ring 15a-3 that rotates integrally with the rotary shaft 10, an outer ring 15a-1 that is fitted into the inner peripheral surface of the bearing housing portion 2b. A plurality of rolling elements 15a-2, a lubricating oil for rolling the rolling elements 15a-2 for lubrication, and a seal plate (not shown) for enclosing the lubricating oil are provided. . The outer ring 15a-1, the rolling element 15a-2, the inner ring 15a-3, and the seal plate are generally made of a conductive metal such as iron. The seal plate is fixed to the outer ring 15a-1, and is electrically connected to the outer ring 15a-1. The seal plate is not in contact with the inner ring 15a-3 and rotates together with the outer ring 15a-1. The inner ring 15 a-3 is attached to the rotary shaft 10 and is electrically connected to the rotary shaft 10.

  The non-board-side bearing 15b is a ball bearing, and is disposed between the inner and outer rings, an inner ring 15b-3 that rotates integrally with the rotary shaft 10, an outer ring 15b-1 that is fitted on the inner peripheral surface of the conductive bracket 20, and the outer ring 15b. And a plurality of rolling elements 15b-2, a lubricating oil for rolling the rolling elements 15b-2, and a seal plate (not shown) for enclosing the lubricating oil. Yes. The outer ring 15b-1, the rolling element 15b-2, the inner ring 15b-3, and the seal plate are generally made of a conductive metal such as iron. The seal plate is fixed to the outer ring 15b-1, and is electrically connected to the outer ring 15b-1. The seal plate is not in contact with the inner ring 15b-3 and rotates together with the outer ring 15b-1. The conductive bracket 20 is in electrical contact with the outer ring 15b-1. Since the inner ring 15b-3 is attached to the rotation shaft 10, it is electrically connected to the rotation shaft 10.

  The board-side fixed disk-shaped conductor 17a-1 is made of a conductive member formed in an annular plate shape, and between the board-side bearing 15a and the rotor magnet 13 (or the resin portion 18) in the axial direction of the rotary shaft 10. And is electrically connected to the outer ring 15 a-1 of the board-side bearing 15 a and fixed to the mold stator 1 without contacting the rotating shaft 10. The inner diameter of the board-side fixed disk-shaped conductor 17a-1 is formed larger than the outer diameter of the rotary shaft 10, and the outer diameter of the board-side fixed disk-shaped conductor 17a-1 is the bearing housing of the board-side fixed disk-shaped conductor 17a-1. It is formed slightly larger than the inner diameter of the inner peripheral portion 2c so that it can be fixed to the inner peripheral portion 2c of the portion 2b.

  FIG. 3 shows a cross-sectional configuration in a plane that includes the rotating shaft 10 and the substrate-side fixed disk-shaped conductor 17a-1 (or the counter-substrate-side fixed disk-shaped conductor 17b-1) and is orthogonal to the axis of the rotating shaft 10. It is shown. The board-side fixed disk-shaped conductor 17a-1 is coaxially disposed with respect to the axis center of the rotary shaft 10 by being fitted into the inner peripheral surface of the bearing housing portion 2b. Further, since the inner diameter is larger than the outer diameter of the rotating shaft 10, a gap 21 as shown in FIG. 3 is formed between the rotating shaft 10 and the substrate-side fixed disk-shaped conductor 17a-1. The Due to the gap 21, the substrate-side fixed disk-shaped conductor 17 a-1 is arranged around the rotating shaft 10 without contacting the rotating shaft 10. And the board | substrate side fixed disk shaped conductor 17a-1 is electrically connected with the outer ring | wheel 15a-1 via the lead wire 16a, as FIG. 2 shows. For example, the lead wire 16a is integrally formed with the mold resin 2, and both ends thereof are provided so as to be exposed to the rotary shaft 10 side from the inner peripheral surface of the bearing housing portion 2b. By providing the lead wire 16a in this way, the connection between one end of the lead wire 16a and the outer ring 15a-1 is facilitated, and similarly the connection between the other end of the lead wire 16a and the board-side fixed disk-shaped conductor 17a-1. Is facilitated.

  The substrate-side rotating disk-shaped conductor 17a-2 is made of a conductive member formed in an annular plate shape, and the substrate-side fixed disk-shaped conductor 17a-1 and the rotor magnet 13 (or the resin portion) in the axial direction of the rotating shaft 10 are formed. 18), and is disposed on the rotating shaft 10 so as to be disposed in the vicinity of the board-side fixed disk-shaped conductor 17a-1 without contacting the board-side fixed disk-shaped conductor 17a-1. The inner diameter of the substrate-side rotating disk-shaped conductor 17a-2 is formed to be slightly smaller than the outer diameter of the rotating shaft 10, and the substrate-side rotating disk-shaped conductor 17a-2 is rotated into the rotating shaft by being press-fitted into the rotating shaft 10. 10 is electrically connected. Further, the outer diameter of the substrate-side rotating disk-shaped conductor 17a-2 is formed smaller than the inner diameter dimension of the inner peripheral portion 2c of the bearing housing portion 2b so as not to contact the inner peripheral portion 2c of the bearing housing portion 2b. ing. The substrate-side rotating disk-shaped conductor 17a-2 is disposed in the vicinity of the substrate-side fixed disk-shaped conductor 17a-1 and is parallel to the substrate-side fixed disk-shaped conductor 17a-1 when being pressed into the rotating shaft 10. Be placed. By arranging in this way, a capacitance is formed between the substrate-side fixed disk-shaped conductor 17a-1 and the substrate-side rotating disk-shaped conductor 17a-2.

  The non-substrate-side fixed disk-shaped conductor 17b-1 is made of a conductive member formed in an annular plate shape. In the axial direction of the rotary shaft 10, the non-substrate-side bearing 15b and the rotor magnet 13 (or the resin portion 18) And is electrically connected to the outer ring 15 b-1 of the non-board-side bearing 15 b and fixed to the mold stator 1 without contacting the rotating shaft 10. The inner diameter of the non-substrate-side fixed disk-shaped conductor 17 b-1 is larger than the outer diameter of the rotating shaft 10. Further, the outer diameter of the anti-substrate-side fixed disk-shaped conductor 17b-1 is set so that the anti-substrate-side fixed disk-shaped conductor 17b-1 can be fixed to the inner peripheral part 2a of the mold resin 2. It is formed slightly larger than the inner diameter dimension.

  The non-substrate-side fixed disk-shaped conductor 17 b-1 formed in this way is fixed to the mold stator 1 by being fitted into the concave portion 19 of the mold resin 2 and is coaxial with the axis center of the rotating shaft 10. Arranged. Moreover, since the inner diameter is formed larger than the outer diameter of the rotating shaft 10, a gap 21 as shown in FIG. 3 is formed between the rotating shaft 10 and the non-substrate-side fixed disk-shaped conductor 17b-1. Is done. The non-substrate-side fixed disk-shaped conductor 17 b-1 is arranged around the rotating shaft 10 without contacting the rotating shaft 10 by the gap 21. And the non-board | substrate side fixed disk shaped conductor 17b-1 is electrically connected with the outer ring | wheel 15b-1 via the bracket 20, as FIG. 1 shows. That is, when the conductive bracket 20 is assembled to the inner peripheral portion 2a of the mold resin 2, the non-substrate-side fixed disk-shaped conductor 17b-1 is in contact with the contact portion 20a on the outer peripheral side of the conductive bracket 20, It is electrically connected to the outer ring 15b-1 via the conductive bracket 20 (see FIG. 1). With this configuration, it is possible to electrically connect the outer ring 15b-1 and the non-board-side fixed disk-shaped conductor 17b-1 without using parts other than the conductive bracket 20.

  In addition, the connection method of the non-board | substrate side fixed disk shaped conductor 17b-1 and the outer ring | wheel 15b-1 is not limited to this. For example, as shown in FIG. 2, it may be configured to connect the non-substrate-side fixed disk-shaped conductor 17b-1 and the outer ring 15b-1 using a lead wire 16b. For example, one end of the lead wire 16b is soldered to the non-substrate-side fixed disk-shaped conductor 17b-1, and the other end of the lead wire 16b is fitted between the outer ring 15b-1 and the conductive bracket 20. For example, even when the conductive bracket 20 and the board-side fixed disk-shaped conductor 17b-1 are not reliably connected due to a manufacturing error of the conductive bracket 20, the outer ring 15b-1 and the board side can be obtained by using the lead wire 16b in this way. Electrical connection with the fixed disk-shaped conductor 17b-1 becomes possible.

  The non-substrate-side rotating disk-shaped conductor 17 b-2 is made of a conductive member formed in an annular plate shape, and the non-substrate-side fixed disk-shaped conductor 17 b-1 and the rotor magnet 13 (or in the axial direction of the rotating shaft 10). The rotating shaft 10 is disposed so as to be positioned in the vicinity of the non-substrate-side fixed disk-shaped conductor 17b-1 without being in contact with the anti-substrate-side fixed disk-shaped conductor 17b-1. Is done. The inner diameter of the non-substrate-side rotating disk-shaped conductor 17b-2 is formed to be slightly smaller than the outer diameter of the rotating shaft 10, and when pressed into the rotating shaft 10, the non-board-side rotating disk-shaped conductor 17b-2 is It is electrically connected to the rotating shaft 10. Further, the outer diameter of the non-substrate-side rotating disk-shaped conductor 17b-2 is formed smaller than the inner diameter of the inner peripheral portion 2a so as not to contact the inner peripheral portion 2a of the mold resin 2. The non-substrate-side rotating disk-shaped conductor 17b-2 is disposed in the vicinity of the anti-substrate-side fixed disk-shaped conductor 17b-1, and is disposed in parallel with the anti-substrate-side fixed disk-shaped conductor 17b-1. By arranging in this way, a capacitance is formed between the non-substrate-side fixed disk-shaped conductor 17b-1 and the anti-substrate-side rotating disk-shaped conductor 17b-2.

  When the rotor assembly 15 is inserted into the recess 19 from the opening of the mold stator 1, the board-side bearing 15a attached to the rotary shaft 10 is incorporated into the bearing housing portion 2b. One end of the rotating shaft 10 passes through the bearing housing portion 2b, and the above-described fan or the like is attached to the rotating shaft 10. On the other hand, an anti-board side bearing 15b is attached to the other end of the rotating shaft 10, and when the conductive bracket 20 is press-fitted into the inner peripheral portion 2a of the mold resin 2 and is fitted so as to close the opening, A non-substrate-side bearing 15 b is incorporated inside the conductive bracket 20.

  The operation will be described below. When a voltage is induced between the inner and outer rings of the substrate-side bearing 15a and the non-substrate-side bearing 15b (hereinafter also simply referred to as “bearings”) as the inverter is switched, the substrate-side fixed disk-shaped conductor 17a-1 and the anti-substrate Side fixed disk-shaped conductor 17b-1 (hereinafter also simply referred to as "fixed disk-shaped conductor"), substrate-side rotating disk-shaped conductor 17a-2 and counter-substrate-side rotating disk-shaped conductor 17b-2 (hereinafter simply referred to as "rotating disk"). (Also referred to as a “shaped conductor”) in a high frequency state. This is because the fixed disk-shaped conductor that is electrically connected to the bearing outer ring and the rotating disk-shaped conductor that is electrically connected to the bearing inner ring are arranged close to each other, thereby rotating the fixed disk-shaped conductor and the bearing outer ring. Capacitance is formed between the disk-shaped conductor and low impedance (conducting state) between the fixed disk-shaped conductor and the rotating disk-shaped conductor with respect to the high-frequency component of the voltage induced between the bearing inner and outer rings. Because. Thereby, since an axial current flows between the fixed disk-shaped conductor and the rotating disk-shaped conductor, the axial current flowing between the bearing inner and outer rings is reduced. Therefore, the occurrence of wavy wear in the inner ring, outer ring, or rolling element is suppressed, and the occurrence of abnormal noise due to the wavy wear phenomenon is suppressed.

  As described above, the electric motor 100 according to the present embodiment includes the stator 6 having the annular stator core 8, the inner side of the stator 6, and the rotating shaft 10 facing the stator core 8. A rotor 14 having permanent magnets (rotor magnets 13) arranged on the outer peripheral side, a first bearing (substrate-side bearing 15a) that rotatably supports one end of the rotating shaft 10, and the other of the rotating shaft 10. In the axial direction between the second bearing (anti-substrate-side bearing 15b) that rotatably supports the end and the stator 6 and the first bearing (substrate-side bearing 15a) in the axial direction of the rotary shaft 10. The board-side bearing in the axial direction of the rotary shaft 10 is composed of a drive circuit board 4 that is arranged substantially perpendicular to the drive circuit board 4 on which a circuit for rotating the rotor 14 is mounted, and a conductive member formed in an annular plate shape. 15a and the rotor magnet 13 between the board side bearings A first fixed disk-shaped conductor (substrate-side fixed disk-shaped conductor 17a-1) that is electrically connected to the outer ring 15a-1 of 5a and is fixed to the mold stator 1 without contacting the rotary shaft 10; , Which is made of a conductive member formed in an annular plate shape, and is positioned between the substrate-side fixed disk-shaped conductor 17a-1 and the rotor magnet 13 in the axial direction of the rotating shaft 10, and is arranged on the substrate-side fixed disk-shaped conductor 17a. -1 is arranged in the vicinity of the substrate-side fixed disk-shaped conductor 17a-1 without contacting the substrate-side fixed disk-shaped conductor 17a-1, the first rotating disk-shaped conductor (substrate-side rotating disk-shaped conductor 17a-2) installed on the rotating shaft 10 And a conductive member formed in the shape of an annular plate, and is positioned between the non-substrate-side bearing 15b and the rotor magnet 13 in the axial direction of the rotating shaft 10, and the outer ring 15b-1 of the anti-substrate-side bearing 15b. And the rotating shaft 1 A second fixed disk-shaped conductor (non-substrate-side fixed disk-shaped conductor 17b-1) fixed to the mold stator 1 without contacting with a conductive member formed in an annular plate shape, and a rotating shaft 10 is located between the non-substrate-side fixed disk-shaped conductor 17b-1 and the rotor magnet 13 in the axial direction of 10 and is not in contact with the anti-substrate-side fixed disk-shaped conductor 17b-1 -1, the second rotating disk-shaped conductor (the non-substrate-side rotating disk-shaped conductor 17b-2) installed on the rotating shaft 10, the stator core 8 and the drive circuit board 4 are integrated. The mold resin 2 is provided with a recess 19 formed so that the rotor 14 can be accommodated therein, and is fitted into the inner peripheral portion 2a of the mold resin 2 so as to close the opening of the recess 19. And the outside of the non-board side bearing 15b And the conductive bracket 20 with the ring fitted inside, so that when a voltage is induced between the bearing inner and outer rings in accordance with the switching of the inverter, the bearing inner and outer rings with respect to the high-frequency component included in this voltage. Between the fixed disk-shaped conductors (17a-1, 17b-1) and the rotating disk-shaped conductors (17a-2, 17b-2), the shaft current is flowing between the bearing inner and outer rings. The axial current is reduced because it flows through the cylindrical conductor and the rotating disk-shaped conductor.

  In addition, since the electric motor 100 according to the present embodiment is not configured such that the movable part and the non-movable part are in contact with each other as in the prior art described in Patent Document 1, there is no problem due to wear, and compared with the prior art. Even during long-term use, the electric corrosion of the bearing can be suppressed.

  In the present embodiment, since the dielectric layer (rotor insulating portion 12) is provided between the stator core 8 and the rotating shaft 10, the rotating shaft 10 and the rotor magnet 13 are insulated. In addition, the rotating shaft 10 and the stator core 8 can be insulated. Therefore, the radial impedance of the rotor 14 is increased, and the axial current flowing from the rotor 14 to the stator 6 can be reduced.

  Further, as shown in FIG. 1, the dielectric layer (rotor insulating portion 12) can be provided between the rotating shaft 10 and the rotor magnet 13, for example. As a result, the rotary shaft 10 and the rotor magnet 13 can be insulated, the impedance in the radial direction of the rotor 14 is increased, and the axial current flowing from the rotor 14 to the stator 6 can be reduced. is there.

  Further, since the mold resin 2 is a thermoplastic resin, low-pressure molding is possible, and the drive circuit board 4 and the like that are weak in strength can be easily integrally molded.

Embodiment 2.
FIG. 4 is a diagram illustrating a manufacturing process of the electric motor 100 according to the second embodiment. The configuration of the electric motor 100 is as described in the first embodiment. Hereinafter, a method for manufacturing the electric motor 100 will be described with reference to FIG.
(1) First, the stator 6 is manufactured (step S1), and the drive circuit board 4 is manufactured (step S2).
(2) Next, the drive circuit board 4 is assembled to the stator 6 to manufacture the stator assembly 3 (step S3).
(3) The stator assembly 3 is integrally formed with a thermosetting resin (mold resin 2) to manufacture the mold stator 1 (step S4).
(4) Then, the board-side bearing 15a is inserted into the bearing housing portion 2b of the mold stator 1, and the board-side fixed disk-shaped conductor 17a-1 is further inserted (step S5).
(5) The rotor 14 is manufactured in parallel with the step S4 (step S6).
(6) The rotating disk-shaped conductors (17a-2, 7b-2) are press-fitted into the rotor 14 (step S7).
(7) Insert the rotor 10 manufactured in step S7 into the recess 19 of the mold stator 1 manufactured in step S5 (step S8).
(8) Then, the non-substrate-side fixed disk-shaped conductor 17b-1 is press-fitted into the inner peripheral portion 2a of the mold stator 1, and then the anti-substrate-side bearing 15b is press-fitted into the rotor 10 (step S9).
(9) Finally, the conductive bracket 20 is press-fitted into the recess 19 of the mold stator 1 to close the opening of the recess 19 (step S10). Thereby, the electric motor 100 is manufactured. By adopting such a manufacturing process, the electric motor 100 according to the present embodiment can be efficiently manufactured.

Embodiment 3.
FIG. 5 is a configuration diagram of an air conditioner according to Embodiment 3. The air conditioner 300 includes an indoor unit 310 and an outdoor unit 320 connected to the indoor unit 310. The indoor unit 310 is equipped with an indoor unit blower (not shown), and the outdoor unit 320 is equipped with an outdoor unit blower 330.

  The outdoor unit blower 330 and the indoor unit blower each incorporate the electric motor 100 described in Embodiment 1 as a drive source. By mounting the electric motor 100 on the outdoor unit blower 330 and the indoor unit blower, which are the main components of the air conditioner 300, the durability of the air conditioner 300 is improved and the bearings (15a, 15b) are generated. Noise due to electric corrosion can be reduced. Noise is a particular problem due to the electric corrosion of these bearings (15a, 15b), and the indoor unit 310 is required to be quiet in order to be used in a living space for a long time, and the resistance to electric corrosion can be improved. This greatly contributes to product reliability. In addition to the air conditioner 300, the electric motor 100 can be used by being mounted on, for example, a ventilation fan, a home appliance, a machine tool, or the like.

  An electric motor according to an embodiment of the present invention, an air conditioner incorporating the electric motor, and a method for manufacturing the electric motor are examples of the contents of the present invention, and are combined with another known technique. Of course, it is possible to change and configure such as omitting a part without departing from the gist of the present invention.

  INDUSTRIAL APPLICABILITY The present invention is mainly applicable to an electric motor, an air conditioner incorporating the electric motor, and a method for manufacturing the electric motor, and is particularly useful as an invention that can suppress electrolytic corrosion of a bearing even during long-term use. is there.

  DESCRIPTION OF SYMBOLS 1 Mold stator, 2 Mold resin, 2a Inner peripheral part, 2b Bearing housing part, 2c Inner peripheral part, 3 Stator assembly, 4 Drive circuit board, 6 Stator, 7 Winding, 8 Stator core, 9 Insulator, DESCRIPTION OF SYMBOLS 10 Rotating shaft, 10a knurl, 11 Position detection magnet, 12 Rotor insulation part, 13 Rotor magnet, 14 Rotor, 15 Rotor assembly, 15a Substrate side bearing, 15b Anti-substrate side bearing, 15a-1, 15b- DESCRIPTION OF SYMBOLS 1 Outer ring, 15a-2, 15b-2 Rolling element, 15a-3, 15b-3 Inner ring, 16a, 16b Lead wire, 17a-1 Substrate side fixed disk-shaped conductor, 17a-2 Substrate side rotating disk-shaped conductor, 17b- DESCRIPTION OF SYMBOLS 1 Anti-substrate side fixed disk-shaped conductor, 17b-2 Anti-substrate side rotation disk-shaped conductor, 18 Resin part, 19 Recessed part, 20 Conductive bracket, 20a Contact part, 21 Air gap, 1 0 motor 300 air conditioner, 310 indoor unit, 320 outdoor unit, 330 outdoor unit blower.

Claims (9)

A stator having an annular stator core;
A rotor having a permanent magnet disposed inside the stator and disposed on the outer peripheral side of the rotating shaft facing the stator core;
A first bearing rotatably supporting one end of the rotating shaft;
A second bearing rotatably supporting the other end of the rotating shaft;
A drive circuit board on which a circuit that rotates and drives the rotor is disposed substantially perpendicular to the axial direction between the stator and the first bearing in the axial direction of the rotating shaft;
It consists of a conductive member formed in the shape of an annular plate, is located between the first bearing and the permanent magnet in the axial direction of the rotary shaft, and is electrically connected to the outer ring of the first bearing. And a first fixed disk-shaped conductor fixed to the stator without contacting the rotating shaft,
It consists of an electroconductive member formed in the shape of an annular plate, and is positioned between the first fixed disk-shaped conductor and the permanent magnet in the axial direction of the rotating shaft, and is in contact with the first fixed disk-shaped conductor A first rotating disk-shaped conductor installed on the rotating shaft so as to be disposed in the vicinity of the first fixed disk-shaped conductor without,
It consists of a conductive member formed in the shape of an annular plate, is located between the second bearing and the permanent magnet in the axial direction of the rotating shaft, and is electrically connected to the outer ring of the second bearing. And a second fixed disk-shaped conductor fixed to the stator without contacting the rotating shaft,
It consists of an electroconductive member formed in the shape of an annular plate, and is located between the second fixed disk-shaped conductor and the permanent magnet in the axial direction of the rotating shaft, and is in contact with the second fixed disk-shaped conductor A second rotating disk-shaped conductor installed on the rotating shaft so as to be disposed in the vicinity of the second fixed disk-shaped conductor without,
Molding resin in which the stator iron core and the drive circuit board are integrally formed, and a recess is formed inside the rotor so as to accommodate the rotor;
A conductive bracket that is fitted into the inner periphery of the mold resin so as to close the opening of the recess, and an outer ring of the second bearing is fitted inside,
An electric motor comprising:   2. The electric motor according to claim 1, wherein the first fixed disk-shaped conductor and the outer ring of the first bearing are electrically connected via a lead wire.   The electric motor according to claim 1 or 2, wherein the second fixed disk-shaped conductor and the outer ring of the first bearing are electrically connected via the conductive bracket.   The electric motor according to claim 1, wherein the second fixed disk-shaped conductor and the outer ring of the first bearing are electrically connected via a lead wire.   5. The electric motor according to claim 1, wherein a dielectric layer is provided between the stator core and the rotation shaft.   The electric motor according to claim 5, wherein the dielectric layer is provided between the rotating shaft and the permanent magnet.   The electric motor according to claim 1, wherein the mold resin is a thermoplastic resin.   An air conditioner comprising the electric motor according to any one of claims 1 to 7. A stator having an annular stator core, a rotor having a permanent magnet disposed inside the stator and disposed on the outer peripheral side of the rotating shaft so as to face the stator core, and one end of the rotating shaft A first bearing that rotatably supports the second shaft, a second bearing that rotatably supports the other end of the rotating shaft, and the stator and the first bearing in the axial direction of the rotating shaft. The drive circuit board is arranged substantially perpendicular to the axial direction and mounted with a circuit for driving the rotor to rotate, and a conductive member formed in an annular plate shape, and the axial direction of the rotary shaft The first bearing is located between the first bearing and the permanent magnet, is electrically connected to the outer ring of the first bearing, and is fixed to the stator without contacting the rotating shaft. A fixed disk-shaped conductor and a conductive member formed in an annular plate shape The first fixed disk-shaped conductor is positioned between the first fixed disk-shaped conductor and the permanent magnet in the axial direction of the rotating shaft, and is not in contact with the first fixed disk-shaped conductor. A first rotating disk-shaped conductor installed on the rotating shaft and a conductive member formed in an annular plate shape so as to be disposed in the vicinity, and the second bearing in the axial direction of the rotating shaft And a second fixed disk-shaped conductor which is located between the permanent magnet and is electrically connected to the outer ring of the second bearing and fixed to the stator without contacting the rotating shaft; A conductive member formed in the shape of an annular plate, located between the second fixed disk-shaped conductor and the permanent magnet in the axial direction of the rotation shaft, and the second fixed disk-shaped conductor; Arranged in the vicinity of the second fixed disk-shaped conductor without contact. As described above, the second rotating disk-shaped conductor installed on the rotating shaft, the stator core and the drive circuit board are integrally formed, and a recess formed to accommodate the rotor therein. And a conductive bracket in which the outer ring of the second bearing is fitted inwardly while being fitted into the inner peripheral part of the mold resin so as to close the opening of the concave portion. A method of manufacturing an electric motor,
Manufacturing the stator;
Manufacturing the drive circuit board;
Assembling the drive circuit board to the stator to produce a stator assembly;
Producing the mold stator by integrally molding the stator assembly with the mold resin; and
Inserting the first bearing and the first fixed disk-shaped conductor into a bearing housing portion of the mold stator;
Manufacturing the rotor;
Press-fitting the first rotating disk-shaped conductor and the second rotating disk-shaped conductor into the rotor;
Inserting the rotor into the recess of the mold stator;
Press-fitting the second fixed disk-shaped conductor into the recess of the mold stator and press-fitting the second bearing into the rotor;
Press-fitting the conductive bracket into the recess of the mold stator and closing the opening of the recess; and
A method for manufacturing an electric motor, comprising:

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