JP5042299B2 - Electric motor, electric motor manufacturing method, and electric device - Google Patents

Description

  The present invention relates to an electric motor that is mounted with a printed wiring board on which a drive circuit is mounted, uses a rolling bearing, and is driven by an inverter. The present invention also relates to a method for manufacturing the electric motor and an electric device such as an air conditioner equipped with the electric motor.

  Conventionally, when an electric motor is operated using an inverter, the carrier frequency of the inverter is set high for the purpose of reducing the noise of the electric motor that is generated when the transistor is switched. If the carrier frequency is set high or the power supply voltage is high, the potential difference that exists between the inner ring and outer ring of the rolling bearing that supports the shaft increases, and the grease in the bearing causes dielectric breakdown. A large current flows. The current flowing through the rolling bearings causes corrosion called electrolytic corrosion on the rolling surfaces of the inner and outer ring raceways and the rolling elements (balls and rollers that roll between the inner and outer rings), thereby deteriorating the durability of the rolling bearings. There was a problem. In addition, there has been a problem that a large noise is generated from the electric motor due to the occurrence of electrolytic corrosion. Various electric motors that solve these problems have been proposed.

  For example, in a stator of a brushless motor molded with an insulating resin, a structure in which the stator iron core is short-circuited with the bracket via the iron core connection terminal and the bracket connection terminal has been proposed (for example, see Patent Document 1).

  Further, in a brushless DC motor that employs a direct PWM (pulse width modulation) system, the flange portion of the bearing holder, the stator core, the core holder, and the iron substrate are fixed together by a tap screw, so that the iron plate portion and the stator core of the iron substrate are fixed. A structure that is fixed to the ground potential has been proposed (see, for example, Patent Document 2).

JP 2007-159302 A Special table 2001-128431 gazette

  However, the electric motor of Patent Document 1 does not decrease the electrostatic capacity between the bearing and the winding held by the mold resin on the side opposite to the bracket, so that current flows due to this electrostatic capacity and generates electrolytic corrosion on the bearing. There was a problem of making it happen.

  In addition, the electric motor of Patent Document 2 has a problem in terms of safety because a metal plate is short-circuited to a circuit ground via a tap screw, particularly when a high voltage power source is provided such as an electric shock.

  The present invention has been made to solve the above-described problems, and reduces the current flowing through the bearing that causes abnormal wear of the bearing, thereby reducing the electric corrosion of the bearing without impairing productivity, quality, and safety. An electric motor that can be suppressed, a method for manufacturing the electric motor, and an electric device are provided.

The electric motor according to this invention is
A stator assembly in which a predetermined number of magnetic steel sheets punched into a predetermined shape are stacked and a stator core that is wound via an insulating part is disposed at the axial end of the stator assembly. A printed circuit board on which a drive circuit is mounted, and a molded stator formed by mounting the printed circuit board on the stator assembly and molding with a mold resin,
A rotor assembly in which a rotor and a bearing constituted by a rolling bearing are fitted to a shaft;
A bracket fixed to the axial end of the mold stator;
In the vicinity of the printed wiring board, a metal plate disposed in contact with the outer surface of the mold resin on the axial end surface on the printed wiring board side of the mold stator,
And an electrical connection member for electrically connecting the metal plate to the stator core.

  In the electric motor according to the present invention, the stator core and the electrically insulated metal plates are electrically connected by the electrical connection member, so that the current flowing through the bearing is reduced or suppressed, and abnormal noise due to abnormal wear is generated. There is an effect to prevent.

FIG. 3 shows the first embodiment and is a cross-sectional view of the electric motor 100. FIG. 5 shows the first embodiment and is a partial longitudinal sectional view of a first bearing 21a. FIG. 5 shows the first embodiment and is a plan view of a metal plate 70. FIG. 5 shows the first embodiment, and is a cross-sectional view of the connection pin 61. FIG. 5 shows the first embodiment and is a cross-sectional view of a printed wiring board 45. FIG. 5 shows the first embodiment and is a plan view of a printed wiring board 45. FIG. 9 shows the first embodiment and is a plan view of a printed wiring board 145 according to a modification. FIG. 3 shows the first embodiment and is a block diagram of a drive circuit 200; FIG. 5 shows the first embodiment and is an external view of an inverter IC 49a. FIG. 5 shows the first embodiment, and shows a path of current flowing through stray capacitance in the electric motor 100. FIG. FIG. 5 shows the first embodiment, and shows a manufacturing process of the electric motor 100. FIG. 5 shows the second embodiment and is a configuration diagram of an air conditioner 300. It is a figure shown for the comparison and the figure which shows the path | route of the electric current which flows through the stray capacitance in the conventional electric motor 400.

Embodiment 1 FIG.
1 to 10 show the first embodiment, FIG. 1 is a sectional view of the electric motor 100, FIG. 2 is a partial longitudinal sectional view of the first bearing 21a, FIG. 3 is a plan view of the metal plate 70, FIG. 5 is a sectional view of the printed wiring board 45, FIG. 6 is a plan view of the printed wiring board 45, FIG. 7 is a plan view of the printed wiring board 145 of a modified example, and FIG. FIG. 9 is an external view of the inverter IC 49a, FIG. 10 is a diagram showing a path of current flowing through the stray capacitance in the electric motor 100, and FIG. 11 is a diagram showing a manufacturing process of the electric motor 100.

  A configuration of the electric motor 100 will be described with reference to FIG. 1. First, an assembly procedure of the electric motor 100 will be described before describing the configuration of the electric motor 100.

  First, the insulating portion 43 is applied to the teeth of the stator core 41, and the winding 42 of the concentrated winding system is further wound to form the stator assembly 40. However, the winding 42 is not limited to the concentrated winding method. Distributed winding may be used.

  A printed wiring board 45 provided with a drive circuit 200 (see FIG. 8) to which a lead wire 47 is assembled is mounted on the stator assembly 40.

  The printed wiring board 45 is disposed at the axial end on the side opposite to the opening of the mold stator 10 (an example of a stator).

  The winding 42 of the stator assembly 40 and the printed wiring board 45 are connected by solder.

  Next, the stator assembly 40 in which the mounting of the printed wiring board 45 is completed is molded with a mold resin to form the mold stator 10.

  The mold stator 10 is open at one end in the axial direction (see FIG. 1, bracket 30 side). As will be described later, the rotor assembly 20 is inserted from the opening of the mold stator 10.

  In the example shown in FIG. 1, the other end of the mold stator 10 in the axial direction (on the bearing support portion 11 side) has a hole that allows the shaft 23 to pass therethrough. A load such as a fan is provided on the shaft 23 protruding from the hole.

  However, the other end part (the bearing support part 11 side) of the axial direction of the mold stator 10 may be closed. In that case, the shaft 23 projects from the hole of the bracket 30 assembled to one end of the mold stator 10 in the axial direction, and a load such as a fan is provided.

  The rotor assembly 20 is inserted into the mold stator 10 from the opening side (see FIG. 1, bracket 30 side).

  The rotor assembly 20 includes at least a rotor 20a, a first bearing 21a (rolling bearing), a second bearing 21b (rolling bearing), and a shaft 23.

  The rotor assembly 20 inserted from one axial end of the mold stator 10 (on the bracket 30 side in FIG. 1) is a first bearing 21a (a rolling bearing, generally fixed to the shaft 23 by press-fitting). Is pushed into the axial end of the mold stator 10 on the side opposite to the opening (on the side of the bearing support 11) until it comes into contact with the bearing support 11 on the side opposite to the opening of the mold stator 10. It is supported by the formed bearing support portion 11. The bearing support portion 11 is formed of a mold resin.

  A metal bracket 30 that supports the second bearing 21 b is press-fitted into the opening side end (see FIG. 1) of the mold stator 10 to close the opening of the mold stator 10.

  The bracket 30 supports the second bearing 21b attached to the rotor assembly 20 by the bearing support portion 30a.

  A donut-shaped metal plate 70 (see FIG. 3) disposed near the printed wiring board 45 on which the drive circuit 200 is mounted and in contact with the outer surface of the mold resin 50 on the axial end surface of the mold stator 10 on the printed wiring board 45 side. ) And a conductive connection pin 61 (electrical connection member, see FIG. 4) penetrating through a through hole (not shown) provided in the mold stator 10 is electrically connected to the stator core 41. By attaching as described above, the electric motor 100 is completed.

  The stator core 41 and the metal plate 70 are electrically connected via connection pins 61.

  An electric motor 100 shown in FIG. 1 includes a mold stator 10 to which a printed wiring board 45 on which at least a drive circuit 200 is mounted, a rotor assembly 20, and a bracket 30 attached to one axial end of the mold stator 10. And a donut-shaped metal plate 70 disposed in contact with the outer surface of the mold resin 50 in the vicinity of the printed wiring board 45 and a through hole provided in the mold stator 10, and the stator core 41 and the metal plate 70. And a connection pin 61 for electrically connecting the two.

  The electric motor 100 is, for example, a brushless DC motor having a permanent magnet 22 in the rotor 20a and driven by an inverter.

The stator assembly 40 has the following configuration.
(1) An electromagnetic steel sheet having a thickness of about 0.1 to 0.7 mm is punched into a strip shape, and a strip-shaped stator core 41 is manufactured by laminating by caulking, welding, bonding, or the like. The strip-shaped stator core 41 includes a plurality of teeth (not shown). Teeth are inside the concentrated windings 42 described later.
(2) The insulating portion 43 is applied to the teeth. The insulating portion 43 is formed integrally with or separately from the stator core 41 using, for example, a thermoplastic resin such as PBT (polybutylene terephthalate).
(3) The concentrated winding 42 is wound around the teeth provided with the insulating portion 43. A plurality of concentrated winding coils are connected to form a three-phase single Y-connection winding. However, distributed winding may be used.
(4) Since it is a three-phase single Y connection, each phase (U phase, V phase, W phase) is connected to the connection side of the insulating portion 43 (on the mold stator 10, the non-opening portion side, the upper side in FIG. 1). ) Is connected to a printed wiring board 45 on which the drive circuit 200 (FIG. 8) is mounted via a winding terminal (not shown).

  The mold stator 10 is configured by molding a stator assembly 40 in which the winding 42 is completed with a mold resin. For the mold resin, for example, a thermosetting resin such as an unsaturated polyester resin is used.

  As already described, the rotor assembly 20 includes at least the rotor 20a, the first bearing 21a (rolling bearing), the second bearing 21b (rolling bearing), and the shaft 23.

  The permanent magnet 22 of the rotor 20a is a ring-shaped resin magnet formed by mixing a thermoplastic material with a magnetic material.

  However, it is not limited to a resin magnet, and a sintered magnet can also be used.

  The permanent magnet 22 may be ferrite or rare earth (neodymium, samarium cobalt, etc.).

  The first bearing 21a and the second bearing 21b are rolling bearings. As shown in FIG. 2, the first bearing 21a (rolling bearing) includes an inner ring 21a-2 that is press-fitted into the shaft 23, an outer ring 21a-1 that is supported by the bearing support portion 11, an inner ring 21a-2, and an outer ring The rolling element 21a-3 which rolls between 21a-1 is provided. The second bearing 21b has the same configuration.

  The printed wiring board 45 is installed on the mold stator 10. In addition to the winding terminals (not shown) provided in the stator assembly 40, the lead wire 47 (see FIG. 1) is also soldered to the printed wiring board 45 via the lead wire fixing component 63 (see FIG. 1). Electrically connected.

  Mounted on the printed wiring board 45 are an inverter IC 49a (see FIG. 9) that drives an electric motor 100 (for example, a brushless DC motor), a Hall IC (position detection element, not shown) that detects the magnetic pole position of the rotor 20a, and the like. The drive circuit 200 (see FIG. 8) is configured.

  As shown in FIG. 3, the donut-shaped metal plate 70 is provided with a through hole 70 a for allowing the connection pin 61 to pass therethrough.

  Further, a hole 70 b having a size that can accommodate the bearing support portion 11 of the mold resin 50 is provided at the center of the metal plate 70. The outer shape of the metal plate 70 is preferably circular, but may be substantially circular or other. The size of the metal plate 70 is preferably not less than the printed wiring board 45 and covering the winding 42 of the stator assembly 40.

  The metal plate 70 is made of, for example, iron, copper, aluminum, or the like.

  As shown in FIG. 4, the connection pin 61 is electrically connected to the metal plate 70 by providing a protrusion 61 a having a substantially semicircular cross section. A portion of the protrusion 61a that contacts the metal plate 70 is referred to as a metal plate connecting portion 61a-1. The cross-sectional shape of the protrusion 61a is not limited to a substantially semicircular shape, but may be a square shape.

  The connection pin 61 is assembled to the insulating portion 43 of the stator assembly 40, and the stator core connection portion 61 b of the connection pin 61 is electrically connected to the stator core 41.

  Since the stator core connecting portion 61b is electrically connected to the stator core 41 and the metal plate connecting portion 61a-1 is further electrically connected to the metal plate 70, the connecting pin 61 is electrically connected to the stator core. 41 and the metal plate 70 are electrically connected.

  Here, the connection pins 61 are conductive portions such as the wiring pattern 80 of the printed wiring board 45, the electronic component 90, the inverter IC 49a (see FIG. 5), and the winding 42 (see FIG. 1) of the stator assembly 40, and the mold resin. The insulation performance is ensured through 50.

  In the case where the printed wiring board 45 is provided between the stator core 41 and the metal plate 70, the connection pin 61 has a notch 45c provided on the outer periphery of the printed wiring board 45 as shown in FIG. Place outside.

  Since the notch 45c provided in the outer peripheral part of the printed wiring board 45 is covered with the mold resin 50, the connection pin 61 and the printed wiring board 45 do not contact each other.

  Moreover, as shown in the printed wiring board 145 of the modified example of FIG. 7, the connection pin 61 may pass through the first through hole 145 a provided in the printed wiring board 145.

  At this time, since the first through hole 145a of the printed wiring board 145 is covered with the mold resin 50, the connection pin 61 does not contact the first through hole 145a of the printed wiring board 145.

  Here, an example of the connection pin 61 is shown, but the metal plate 70 is attached to the outside of the axial end surface of the mold stator 10 on the printed wiring board 145 side, and fixed to the metal plate 70 using a tap screw (not shown). The cores 41 may be connected.

  Further, the metal plate 70 is attached to the outside of the end surface in the axial direction on the printed wiring board 145 side of the mold stator 10 in which the stator core 41 is threaded, and the metal plate 70 and the stator core are formed using conductive screws. 41 may be connected.

  As shown in the sectional view of the printed wiring board 45 in FIG. 5, the printed wiring board 45 includes a wiring pattern 80 to which an electronic component 90 and an inverter IC 49a are electrically connected.

  Although a single-sided board is illustrated here as the printed wiring board 45, a double-sided board having a wiring pattern on both sides and a multilayer printed wiring board having a wiring pattern inside may be used.

  The electric motor 100 is driven by an inverter using a PWM (Pulse Width Modulation) method. The drive circuit 200 includes a position detection circuit 110, a waveform generation circuit 120, a pre-driver circuit 130, and a power circuit 140 (see FIG. 8).

  The position detection circuit 110 detects the magnetic pole of the position detection magnet 25 (see FIG. 1) of the rotor 20a with a Hall IC 53 (see FIG. 1) or the like.

  When the position detection magnet 25 is not used, the magnetic pole of the permanent magnet 22 of the rotor 20a is detected by a Hall IC 53 (see FIG. 1) or the like.

  The waveform generation circuit 120 generates a PWM signal for driving the inverter based on the speed command signal for instructing the rotation speed of the rotor 20 a and the position detection signal from the position detection circuit 110, and outputs the PWM signal to the pre-driver circuit 130. To do.

  The pre-driver circuit 130 outputs a transistor drive signal that drives the transistors 141 (six) of the power circuit 140.

  The power circuit 140 includes a DC power supply input unit and an inverter output unit, and includes an arm in which a transistor 141 and a diode 142 are connected in parallel and further connected in series. A current detection circuit (not shown) is provided on one side of the DC power supply input unit and outputs a current detection signal.

  Since the electric motor 100 has three phases, a three-arm inverter output unit is connected to each winding. The DC power supply input unit is connected with AC power of commercial power, for example, 141V, 282V, or 325V DC power supply +, − obtained by rectifying 100V, 200V, or 230V.

  When the speed command signal is input to the drive circuit 200, the waveform generation circuit 120 sets the energization timing to each of the three-phase windings 42 according to the position detection signal and generates a PWM signal according to the input of the speed command signal. ,Output.

  The pre-driver circuit 130 to which the PWM signal output from the waveform generation circuit 120 is input drives the transistor 141 in the power circuit 140.

  The inverter output unit drives the transistor 141 to apply a voltage to the winding 42, a current flows through the winding 42, torque is generated, and the rotor assembly 20 rotates. It becomes the rotational speed of the electric motor 100 according to a speed command signal. The motor 100 is also stopped by a speed command signal.

  As shown in FIG. 9, the inverter IC 49a includes the power circuit 140 and the waveform generation circuit 120 of FIG. 8 in a package 49a-1, and leads 49a-3 connected to these circuits are provided outside the package 49a-1. It has a heat radiating fin 49a-2 that protrudes and radiates heat from the built-in circuit.

  FIG. 13 is a diagram for comparison, and is a diagram illustrating a path of a current flowing through the stray capacitance in the conventional electric motor 400. In the path of the current flowing through the stray capacitance in the conventional electric motor 400 shown in FIG. 13, the current path of the printed wiring board 45, the first bearing 21a, the shaft 23, the stator core 41, the winding 42, and the printed wiring board 45. Current flows at 5b.

  Between the printed wiring board 45 and the first bearing 21a, between the outer ring 21a-1 and the inner ring 21a-2 of the first bearing 21a, between the shaft 23 and the stator core 41, and between the stator core 41 and the winding. Since the wires 42 are coupled with each other by stray capacitance, a large potential difference is generated between the inner ring 21a-2 and the outer ring 21a-1 of the first bearing 21a, and the grease in the first bearing 21a is reduced. Since a large current flows due to dielectric breakdown, both the races of the inner ring 21a-2 and the outer ring 21a-1 (see FIG. 2) and the rolling surfaces of the rolling elements 21a-3 are corroded.

  FIG. 10 shows a path of current flowing through the stray capacitance in the electric motor 100. Between the wiring pattern 80 and the winding 42 of the printed wiring board 45, between the metal plate 70 and the connection pin 61, between the connection pin 61 and the stator core 41, and the inner ring 21-2 of the first bearing 21a. The shaft 23 is electrically connected.

  Between the metal plate 70 and the conductive portion such as the wiring pattern 80 of the printed wiring board 45, between the metal plate 70 and the first bearing 21a, and between the outer ring 21a-1 and the inner ring 21a-2 of the first bearing 21a. Between the shaft 23 and the stator core 41 and between the stator core 41 and the winding 42 are coupled by stray capacitances.

  Since a mold resin 50 having a dielectric constant higher than that of air is interposed between the metal plate 70 and the printed wiring board 45, the stray capacitance between the metal plate 70 and the printed wiring board 45 is large. For the stray capacitance between the conductive portion such as the metal plate 70 and the first bearing 21a, between the outer ring 21a-1 and the inner ring 21a-2 of the first bearing 21a, the shaft 23 and the stator. Each stray capacitance with the iron core 41 is very small.

  During operation of the electric motor 100, the printed wiring board 45, the metal plate 70, the connection pin 61, the stator core 41, the winding wire are obtained by electrically connecting the stator core 41 and the metal plate 70 with the connection pins 61. 42, a current flows through the current path 5a of the printed wiring board 45. The potential of the stator core 41 connected to the metal plate 70 is also stabilized. The potential difference between the inner ring 21a-2 and the outer ring 21a-1 of the first bearing 21a is greatly reduced, and the path of the first bearing 21a, the shaft 23, the stator core 41, the winding 42, and the printed wiring board 45. The current flowing through is very small.

The manufacturing process of the electric motor 100 will be described with reference to FIG. The manufacturing process of the electric motor 100 is as follows. Either the rotor assembly 20 and the mold stator 10 may be in order, or may be manufactured in parallel.
(1) The rotor 20a, the first bearing 21a, and the second bearing 21b are attached to the shaft 23 (step 1).
(2) The rotor assembly 20 is assembled by magnetizing the permanent magnets 22 and the like of the rotor 20a (step 2).
(3) The insulating part 43 is applied to the stator core 41 using resin (step 3).
(4) Concentrated windings 42 are applied to the insulating portion 43 to form the stator assembly 40 (step 4). In addition, the electronic component 90 and the like are mounted on the printed wiring board 45.
(5) The printed wiring board 45 on which the lead wire 47 is assembled and the drive circuit 200 is mounted is disposed on the insulating portion 43 of the stator assembly 40 (step 5).
(6) The winding 42 and the wiring pattern 80 of the printed wiring board 45 are connected by solder (step 6).
(7) The stator assembly 40 is molded with mold resin to form the mold stator 10 (step 7).
(8) The rotor assembly 20 is inserted into the mold stator 10 through the opening, and the rotor assembly 20 is inserted until the first bearing 21a contacts the bearing support portion 11 of the mold stator 10 (step 8). ).
(9) The bracket 30 is press-fitted into the mold stator 10 (step 9).
(10) The metal plate 70 is attached to the mold stator 10 (step 10).
(11) The connection pin 61 is attached so as to penetrate through the metal plate 70 and the through hole provided in the mold stator 10 and to be electrically connected to the stator core 41 (step 11).

  As described above, the present embodiment reduces the current flowing through the first bearing 21a by connecting the stator core 41 and the metal plate 70 with the connection pin 61, and the first bearing due to electrolytic corrosion. Since the abnormal wear of 21a and the generation | occurrence | production of abnormal sound are prevented, the reliable electric motor 100 can be provided.

  This is particularly effective for reducing the current flowing through the bearing when the electric motor 100 is operated using an inverter.

  Further, the printed wiring board 45 is provided with a first through hole 145a having a minimum area for penetrating the connection pin 61, or a cutout portion 45c is provided on the outer peripheral portion of the printed wiring board in order to dispose the connection pin 61. Therefore, the usable area of the printed wiring board 45 can be increased. The restriction on the position where the connection pin 61 is arranged is reduced.

  Moreover, the drive circuit 200 is inverter drive by a PWM system, and can suppress the current flowing through the first bearings 21a and 21b in synchronization with switching.

  Moreover, since the connection pin 61 is used for the connection between the mold stator 10 and the metal plate 70, the number of connection members is reduced, and the connection can be made easily.

  Further, by connecting the stator core 41 and the metal plate 70 with screws, the reliability is improved by a reliable connection, and the metal plate 70 can be easily attached and detached, thereby improving the recyclability.

  1 has a structure in which a permanent magnet 22 (resin magnet) is integrally formed on a shaft 23. An electromagnetic steel plate laminated on the outer periphery of the shaft 23 is arranged, and the rotor 20a shown in FIG. The structure which attached the ring-shaped magnet, or the structure which embedded the magnet inside the electromagnetic steel plate may be sufficient.

  Further, the position detection circuit 110 in the block diagram of the drive circuit 200 shown in FIG. 8 shows an example in which the magnetic pole of the position detection magnet 25 of the rotor 20a is detected by the Hall IC 53 or the like. A method of estimating the position of the permanent magnet 22 of the rotor 20a from the current flowing through the output unit and the output voltage in the waveform generation circuit 120 may be used, or sensorless driving without using a sensor such as the Hall IC 53 may be used.

  According to the above manufacturing process, since the connection pin 61 is attached in the final process of assembling the electric motor 100, the work process is easy and the increase in the cost of the electric motor 100 can be minimized.

  Here, the connection pin 61 is attached in the final process, but after the connection pin 61 is attached to the stator core 41, the insulating portion 43, the winding 42, the printed wiring board 45, etc. are assembled and molded resin molding is performed. However, the same effect can be obtained.

  Further, the connection pin 61 has a straight shape with no semicircular portion, and a method of pressing and crushing the protruding portion from the metal plate 70 in the final process, or a method of tightening the mold resin 50 via the metal plate 70 with a screw. However, since the process is simple, there is little capital investment and it can be manufactured at low cost.

Embodiment 2. FIG.
FIG. 12 is a diagram illustrating the second embodiment, and is a configuration diagram of the air conditioner 300.

  The air conditioner 300 (an example of an electric device) 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 include the electric motor 100 of the first embodiment as a drive source.

  The durability of the air conditioner 300 is improved by mounting the electric motor 100 of the first embodiment on the outdoor unit blower 330 and the indoor unit blower that are main components of the air conditioner 300.

  In the above embodiment, the electric motor 100 including the permanent magnet 22 in the rotor 20a is shown. However, for example, an induction motor that does not include the permanent magnet 22 in the rotor 20a may be used.

  As an application example of the electric motor of the present invention, the electric motor can be used by being mounted on an electric device such as a ventilation fan, a home appliance, or a machine tool.

  5a Current path, 5b Current path, 10 Mold stator, 11 Bearing support, 20 Rotor assembly, 20a Rotor, 21a First bearing, 21a-1 Outer ring, 21a-2 Inner ring, 21a-3 Rolling element, 21b Second bearing, 22 permanent magnet, 23 shaft, 25 position detecting magnet, 30 bracket, 30a bearing support, 40 stator assembly, 41 stator core, 42 winding, 43 insulation, 45 printed wiring board, 45c Notch, 47 Lead wire, 49a Inverter IC, 49a-1 package, 49a-2 Radiation fin, 49a-3 Lead, 50 Mold resin, 53 Hall IC, 61 Connection pin, 61a Protrusion, 61a-1 Metal plate connection Part, 61b Stator core connection part, 63 Lead wire fixing part, 70 Metal plate, 70a Through hole, 70b 80 wiring patterns, 90 electronic components, 100 motors, 110 position detection circuits, 120 waveform generation circuits, 130 pre-driver circuits, 140 power circuits, 141 transistors, 142 diodes, 145 printed wiring boards, 145a first through holes, 200 Drive circuit, 300 air conditioner, 310 indoor unit, 320 outdoor unit, 330 blower for outdoor unit, 400 electric motor.

Claims (7)

A rotor assembly in which a rotor, a first bearing constituted by a rolling bearing, and a second bearing constituted by a rolling bearing are fitted to a shaft;
A stator assembly in which a predetermined number of magnetic steel sheets punched into a predetermined shape are laminated and a winding is provided via an insulating portion on a stator core, and arranged at the axial end of the stator assembly is includes a printed circuit board driving circuit is mounted, and mounting the printed circuit board to the stator assembly, a mold stator that is formed by molding with a molding resin, axial A mold stator in which an opening is formed at one end and a bearing support that supports the first bearing at the other end in the axial direction is formed by a part of the mold resin ;
A bracket wherein said fixed to one axial end of the mold the stator so as to close the opening of the mold the stator, you support the second bearing,
In the printed wiring board near the metal plate disposed in contact with the outer surface of the mold resin other axial end of said mold stator,
An electric motor comprising: an electrical connection member that electrically connects the metal plate to the stator core. The electric motor according to claim 1, wherein a hole having a size capable of accommodating a bearing support portion of the mold stator is provided in a central portion of the metal plate. 3. The electric motor according to claim 1, wherein the electrical connection member is composed of a conductive connection pin or a conductive screw . Wherein the electrical connection member, constructed of a conductive thread, the stator core, according to claim 1 or claim 2 electric motor, wherein the subjected to thread cutting for attaching the screw.   5. The electric motor according to claim 1, wherein the drive circuit is an inverter drive circuit based on a PWM (Pulse Width Modulation) method.   An electric apparatus comprising the electric motor according to any one of claims 1 to 5. A method of manufacturing an electric motor according to claim 1,
Attaching the rotor and the bearing to the shaft, magnetizing a permanent magnet of the rotor to form the rotor assembly,
The printed wiring board in which the stator core is provided with the insulating portion, the winding is provided on the insulating portion to form the stator assembly, and the drive circuit is mounted on the insulating portion of the stator assembly. And connecting the windings to the printed wiring board using solder, and molding the stator assembly with a mold resin to form a mold stator,
Inserting the rotor assembly into the mold stator;
Press-fit the bracket into the axial end of the mold stator,
Attaching the metal plate to the mold stator,
A method for manufacturing an electric motor, wherein the electrical connecting member is attached to the mold stator.

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