JP7256479B2 - Automotive electric compressor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a vehicle-mounted electric compressor.

As a configuration of a common mode choke coil used in an inverter device that drives an electric motor in an automotive electric compressor, Patent Document 1 discloses a structure in which the choke coil is covered with an annular conductor. A plate-like conductor converts the current flowing into the heat into heat. In this electric compressor, since the common mode choke coil can also reduce the normal mode noise, the normal mode choke coil is not required, and an increase in size can be suppressed.

JP 2019-187228 A

By the way, in order for the conductive material to function as a magnetic shield, it is necessary to continuously cover (loop) the periphery of the winding, which poses a problem in terms of assembly. Specifically, regarding the ease of assembly, for common mode choke coils already mounted on the board, the windings have connection ends (leads) for electrical connection with the circuit board. Since (leads) interfere with each other, it is not possible to assemble parts that are integrally molded in a cylindrical shape in advance. Interference with the connection end (lead) can be avoided by processing the conductor so that it is wrapped around the common mode choke coil already mounted on the board, but in this case, the clearance between the conductor and the common mode choke coil is difficult to ensure as designed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle-mounted electric compressor that can be easily assembled.

An in-vehicle electric compressor for solving the above problems includes a compressing section that compresses fluid, an electric motor that drives the compressing section, and an inverter device that drives the electric motor, wherein the inverter device comprises: an inverter circuit; and a noise reduction unit that is provided on the input side of the inverter circuit and that reduces common mode noise and normal mode noise included in the direct current that is input to the inverter circuit, the noise reduction unit comprising: A circuit board, a common mode choke coil mounted on the circuit board, and a smoothing capacitor mounted on the circuit board and forming a low-pass filter circuit together with the common mode choke coil, wherein the common mode choke coil is , an annular core, a pair of windings wound around the core, and an annular conductor covering both the pair of windings, wherein the conductor is a metal plate. and a second conductor which is a metal plate, wherein the first conductor is arranged to be sandwiched between the circuit board and the core, and the second conductor sandwiches the core together with the circuit board. a pair of through holes are formed in the circuit board; the first conductor has a pair of first insertion portions that are respectively inserted into the pair of through holes; has a pair of second insertion portions that are respectively inserted into the pair of through holes, and the pair of first insertion portions and the pair of second insertion portions are electrically connected to each other. and

According to this, the ring-shaped conductor is divided in the circumferential direction into the first conductor, which is a metal plate, and the second conductor, which is a metal plate. Assembleability is improved by sandwiching. Specifically, the clearance between the conductors and the common mode choke coil is secured according to the design value by assembling the first conductor, the core, and the second conductor in this order to the circuit board so as to pass through the pair of through holes. It is possible to easily assemble a structure in which the ring-shaped conductor covers the core.

Further, in the vehicle-mounted electric compressor, the pair of first insertion portions and the pair of second insertion portions may be soldered while protruding from the circuit board through the pair of through holes.

According to this, both ends of the first conductor and both ends of the second conductor can be soldered in the same process as the soldering of the common mode choke coil and the circuit board. As a result, it is possible to improve the assemblability while stabilizing the electrical connection.

Further, in the on-vehicle electric compressor, an insulator may be interposed between the first conductor and the pair of windings and between the second conductor and the pair of windings.
Further, in the on-vehicle electric compressor, the insulator is arranged on a surface of the first conductor facing the pair of windings and on a surface of the first conductor facing the pair of windings of the second conductor. It is preferable that the first insulator and the second insulator are formed in a ring shape.

Further, in the vehicle-mounted electric compressor, the first conductor and the second conductor may be soldered to the circuit board. In this case, it is excellent in earthquake resistance.

According to the present invention, it is possible to improve the assemblability.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic diagram which shows the outline|summary of the vehicle electric compressor. A circuit diagram of a driving device and an electric motor. (a) is a plan view of the circuit board and the common mode choke coil, (b) is a right side view of the circuit board and the common mode choke coil, and (c) is a sectional view taken along line AA of (a). (a) is a plan view of the common mode choke coil, (b) is a right side view of the common mode choke coil, and (c) is a cross-sectional view taken along line AA of (a). 3 is a perspective view of a common mode choke coil; FIG. (a) is a plan view of the case, the core, and the winding; (b) is a right side view of the case, the core, and the winding; (c) is a sectional view taken along the line AA of (a). (a) is a plan view of the metal plate, (b) is a right side view of the metal plate, and (c) is a cross-sectional view taken along line AA of (a). (a) is a plan view of the circuit board and the metal plate, and (b) is an exploded view of the circuit board and the metal plate taken along line AA of (a). (a) is a partial plan view of a circuit board and a common mode choke coil, (b) is a sectional view taken along line AA of (a), and (c) is a view of (a) viewed from arrow B. FIG. (a) is a plan view of a common mode choke coil for explaining the action, and (b) is a cross-sectional view taken along line AA of (a).

An embodiment embodying the present invention will be described below with reference to the drawings. The vehicle-mounted electric compressor of this embodiment includes a compression section that compresses a refrigerant as a fluid, and is used in a vehicle-mounted air conditioner. That is, the fluid to be compressed by the vehicle-mounted electric compressor in this embodiment is the refrigerant.

As shown in FIG. 1 , an in-vehicle air conditioner 10 includes an in-vehicle electric compressor 11 and an external refrigerant circuit 12 that supplies refrigerant as a fluid to the in-vehicle electric compressor 11 . The external refrigerant circuit 12 has, for example, a heat exchanger and an expansion valve. The in-vehicle air conditioner 10 cools and heats the interior of the vehicle by compressing a refrigerant by an in-vehicle electric compressor 11 and performing heat exchange and expansion of the refrigerant by an external refrigerant circuit 12 .

The in-vehicle air conditioner 10 includes an air conditioning ECU 13 that controls the entire in-vehicle air conditioner 10 . The air-conditioning ECU 13 is configured to be able to grasp the vehicle interior temperature, the set temperature of the car air conditioner, etc., and based on these parameters, transmits various commands such as an ON/OFF command to the vehicle-mounted electric compressor 11 .

The vehicle-mounted electric compressor 11 includes a housing 14 in which an intake port 14a through which refrigerant is sucked from an external refrigerant circuit 12 is formed.
The housing 14 is made of a heat-conducting material (for example, a metal such as aluminum). The housing 14 is grounded to the body of the vehicle.

Housing 14 has an inlet housing 15 and an outlet housing 16 assembled together. The suction housing 15 has a bottomed cylindrical shape that is open in one direction, and has a plate-like bottom wall portion 15a and side wall portions 15b that rise from the peripheral edge portion of the bottom wall portion 15a toward the discharge housing 16. there is The bottom wall portion 15a is, for example, substantially plate-shaped, and the side wall portion 15b is, for example, substantially cylindrical. The discharge housing 16 is attached to the suction housing 15 while closing the opening of the suction housing 15 . An internal space is thereby formed in the housing 14 .

The suction port 14 a is formed in the side wall portion 15 b of the suction housing 15 . More specifically, the suction port 14 a is arranged closer to the bottom wall portion 15 a than the discharge housing 16 in the side wall portion 15 b of the suction housing 15 .

The housing 14 is formed with a discharge port 14b through which refrigerant is discharged. The discharge port 14b is formed in the discharge housing 16, more specifically, in a portion of the discharge housing 16 facing the bottom wall portion 15a.

The in-vehicle electric compressor 11 includes a rotating shaft 17 , a compressing section 18 and an electric motor 19 housed in a housing 14 .
The rotary shaft 17 is rotatably supported with respect to the housing 14 . The rotary shaft 17 is arranged such that its axial direction coincides with the thickness direction of the plate-like bottom wall portion 15a (in other words, the axial direction of the cylindrical side wall portion 15b). The rotary shaft 17 and the compression section 18 are connected.

The compression portion 18 is arranged closer to the discharge port 14b than the suction port 14a (in other words, the bottom wall portion 15a) in the housing 14 . The compression part 18 compresses the refrigerant sucked into the housing 14 from the suction port 14a by rotating the rotating shaft 17, and discharges the compressed refrigerant from the discharge port 14b. In addition, the concrete structure of the compression part 18 is arbitrary, such as a scroll type, a piston type, and a vane type.

The electric motor 19 is arranged in the housing 14 between the compression portion 18 and the bottom wall portion 15a. The electric motor 19 drives the compressing portion 18 by rotating the rotating shaft 17 in the housing 14 . The electric motor 19 has, for example, a cylindrical rotor 20 fixed to the rotating shaft 17 and a stator 21 fixed to the housing 14 . The stator 21 has a cylindrical stator core 22 and coils 23 wound around teeth formed on the stator core 22 . The rotor 20 and the stator 21 face each other in the radial direction of the rotating shaft 17 . When the coil 23 is energized, the rotor 20 and the rotary shaft 17 rotate, and the refrigerant is compressed by the compression section 18 .

As shown in FIG. 1 , the vehicle-mounted electric compressor 11 includes a drive device 24 for driving an electric motor 19 and receiving DC power, and a cover member that partitions a housing chamber S0 that houses the drive device 24 . 25.

The cover member 25 is made of a heat-conducting non-magnetic conductive material (for example, a metal such as aluminum).
The cover member 25 has a bottomed cylindrical shape that opens toward the housing 14 , more specifically, toward the bottom wall portion 15 a of the suction housing 15 . The cover member 25 is attached to the bottom wall portion 15a of the housing 14 by bolts 26 with the open end abutting against the bottom wall portion 15a. The opening of the cover member 25 is closed by the bottom wall portion 15a. The accommodation chamber S0 is formed by the cover member 25 and the bottom wall portion 15a.

The accommodation chamber S0 is arranged outside the housing 14, and is arranged on the side opposite to the electric motor 19 with respect to the bottom wall portion 15a. The compression section 18 , the electric motor 19 and the driving device 24 are arranged in the axial direction of the rotating shaft 17 .

A connector 27 is provided on the cover member 25 and the driving device 24 is electrically connected to the connector 27 . Direct current power is input to the driving device 24 from an in-vehicle power storage device 28 mounted on the vehicle via a connector 27, and the air conditioning ECU 13 and the driving device 24 are electrically connected. The vehicle-mounted power storage device 28 is a DC power supply mounted on the vehicle, such as a secondary battery or a capacitor.

As shown in FIG. 1, a circuit board 29 is arranged in the accommodation room S0. The circuit board 29 is plate-shaped. The circuit board 29 is opposed to the bottom wall portion 15a with a predetermined gap in the axial direction of the rotating shaft 17. As shown in FIG. The drive device 24 includes an inverter device 30 and two connection lines EL<b>1 and EL<b>2 used for electrically connecting the connector 27 and the inverter device 30 . The driving device 24 is configured using a circuit board 29 .

The inverter device 30 is for driving the electric motor 19 . The inverter device 30 includes an inverter circuit 31 (see FIG. 2) and a noise reduction section 32 (see FIG. 2). The inverter circuit 31 is for converting DC power into AC power. The noise reduction section 32 is provided on the input side of the inverter circuit 31 and serves to reduce common mode noise and normal mode noise contained in the DC current input to the inverter circuit 31 .

Next, electrical configurations of the electric motor 19 and the driving device 24 will be described.
As shown in FIG. 2, the coil 23 of the electric motor 19 has a three-phase structure including, for example, a u-phase coil 23u, a v-phase coil 23v, and a w-phase coil 23w. Each of the coils 23u to 23w is Y-connected, for example.

The inverter circuit 31 includes u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 23u, v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 23v, and w-phase switching elements Qw1 and Qw1 corresponding to the w-phase coil 23w. and Qw2. Each switching element Qu1-Qw2 is a power switching element such as an IGBT. The switching elements Qu1 to Qw2 have free wheel diodes (body diodes) Du1 to Dw2.

The u-phase switching elements Qu1 and Qu2 are connected in series with each other via a connection line, and the connection line is connected to the u-phase coil 23u. A series connection of the u-phase switching elements Qu1 and Qu2 is electrically connected to both connection lines EL1 and EL2. ing.

The other switching elements Qv1, Qv2, Qw1 and Qw2 are connected in the same manner as the u-phase switching elements Qu1 and Qu2 except that the corresponding coils are different.

The driving device 24 includes a control section 33 that controls switching operations of the switching elements Qu1 to Qw2. The controller 33 can be implemented, for example, by one or more dedicated hardware circuits and/or one or more processors (control circuits) that operate according to computer programs (software). The processor includes a CPU and memory, such as RAM and ROM, which stores, for example, program code or instructions configured to cause the processor to perform various processes. Memory or computer-readable media includes any available media that can be accessed by a general purpose or special purpose computer.

The control unit 33 is electrically connected to the air conditioning ECU 13 via the connector 27, and periodically turns ON/OFF the switching elements Qu1 to Qw2 based on commands from the air conditioning ECU 13. FIG. Specifically, the control unit 33 performs pulse width modulation control (PWM control) on the switching elements Qu1 to Qw2 based on a command from the air conditioning ECU 13 . More specifically, the control unit 33 generates the control signal using the carrier signal (carrier wave signal) and the command voltage value signal (comparison target signal). Then, the control unit 33 performs ON/OFF control of the respective switching elements Qu1 to Qw2 using the generated control signal, thereby converting DC power into AC power.

The noise reduction section 32 includes a circuit board 29 (see FIG. 1), a common mode choke coil 34 mounted on the circuit board 29 and an X capacitor 35 mounted on the circuit board 29 . The X capacitor 35 as a smoothing capacitor forms a low-pass filter circuit 36 together with the common mode choke coil 34 . The low-pass filter circuit 36 is provided on the connection lines EL1 and EL2. The low-pass filter circuit 36 is provided between the connector 27 and the inverter circuit 31 in terms of circuitry.

Common mode choke coils 34 are provided on both connection lines EL1 and EL2.
The X-capacitor 35 is provided in the rear stage (inverter circuit 31 side) with respect to the common mode choke coil 34, and is electrically connected to both connection lines EL1 and EL2. The common mode choke coil 34 and the X capacitor 35 constitute an LC resonance circuit. That is, the low-pass filter circuit 36 of this embodiment is an LC resonance circuit including the common mode choke coil 34 .

Both Y capacitors 37, 38 are connected in series with each other. Specifically, the drive device 24 includes a bypass line EL3 that connects one end of the first Y capacitor 37 and one end of the second Y capacitor 38 . The bypass line EL3 is grounded to the vehicle body.

A series connection body of both Y capacitors 37 and 38 is provided between the common mode choke coil 34 and the X capacitor 35 and electrically connected to the common mode choke coil 34 . The other end of the first Y capacitor 37 opposite to the one end is connected to the first connection line EL1, more specifically, the first winding of the common mode choke coil 34 in the first connection line EL1 and the inverter circuit 31. connected to the part that The other end of the second Y capacitor 38 opposite to the one end connects the second connection line EL2, more specifically, the second winding of the common mode choke coil 34 in the second connection line EL2 to the inverter circuit 31. connected to the part that

For example, a PCU (power control unit) 39 is installed separately from the driving device 24 as an in-vehicle device in the vehicle. The PCU 39 uses the DC power supplied from the in-vehicle power storage device 28 to drive a driving motor and the like mounted on the vehicle. That is, in the present embodiment, the PCU 39 and the drive device 24 are connected in parallel to the vehicle-mounted power storage device 28 , and the vehicle-mounted power storage device 28 is shared by the PCU 39 and the drive device 24 .

The PCU 39 includes, for example, a boost converter 40 that has a boost switching element and periodically turns ON/OFF the boost switching element to boost the DC power of the vehicle-mounted power storage device 28 , and the vehicle-mounted power storage device 28 . and a power supply capacitor 41 connected thereto. Although not shown, the PCU 39 includes a drive inverter that converts the DC power boosted by the boost converter 40 into drive power that can drive the drive motor.

In such a configuration, noise generated due to switching of the boost switching element flows into the driving device 24 as normal mode noise. In other words, normal mode noise includes a noise component corresponding to the switching frequency of the boost switching element.

Next, the configuration of the common mode choke coil 34 is shown in FIGS. 3(a), (b), (c), FIGS. ), (c), FIGS. 7(a), (b), (c), FIGS. 8(a), (b), FIGS. 9(a), (b), (c), FIG. 10(a), Description will be made using (b).

The common mode choke coil 34 is for suppressing transmission of high-frequency noise generated by the PCU 39 on the vehicle side to the inverter circuit 31 on the compressor side. It is used as the L component in a low-pass filter circuit (LC filter) 36 for removing noise (differential mode noise). That is, it is possible to cope with common mode noise and normal mode noise (differential mode noise), and instead of using a common mode choke coil and a normal mode (differential mode) choke coil, one choke coil is used for both. Mode noise can be dealt with.

In the drawings, triaxial orthogonal coordinates are defined, the axial direction of the rotating shaft 17 in FIG. 1 is the Z direction, and the directions orthogonal to the Z direction are the X and Y directions.
As shown in FIGS. 4A, 4B, and 4C, the common mode choke coil 34 includes a case 50, a core 60, a first winding 70, a second winding 71, and an annular coil. and a metal plate 80 as a conductor. Windings 70 and 71 are wound around a case 50 containing a core 60, and a metal plate 80 is wound around the windings 70 and 71 before use. A first winding 70 and a second winding 71 are a pair of windings in the common mode choke coil 34 and are wound around the core 60 .

As shown in FIGS. 6(a), (b), and (c), the core 60 is accommodated inside the case 50. As shown in FIG. The core 60 has a rectangular cross section as shown in FIG. 6(c), and has a substantially rectangular annular shape as a whole on the XY plane shown in FIG. 6(a).

As shown in FIGS. 6A, 6B, and 6C, the case 50 is annular, made of resin, and has electrical insulation. The case 50 includes a body portion 51 and walls 52 . The body portion 51 covers the entire core 60 except for the opening 51a (see FIG. 5). Windings 70 and 71 are wound around the body portion 51 as shown in FIGS. The opening 51a in FIG. 5 is provided between the windings 70 and 71, and the opening 51a exposes a portion of the core 60 between the windings 70 and 71 to the outside.

The wall 52 is provided between the windings 70 and 71 on the inner peripheral surface side of the core 60 so as to extend in the Z direction. A wall 52 separates windings 70 and 71 .
As shown in FIGS. 6A, 6B, and 6C, the first winding 70 is wound around the outer surface of the case 50. As shown in FIGS. The second winding 71 is wound around the outer surface of the case 50 . Specifically, the core 60 includes a first linear portion 61 and a second linear portion 62, and the first linear portion 61 and the second linear portion 62 extend linearly parallel to each other. At least a portion of the first winding 70 is wound around the first linear portion 61 . At least a portion of the second winding 71 is wound around the second straight portion 62 . The winding directions of both windings 70 and 71 are opposite to each other. Also, the first winding 70 and the second winding 71 face each other while being separated from each other.

As shown in FIGS. 3(a), (b), (c), FIGS. 4(a), (b), (c), and FIG. is making A copper plate, for example, can be used as the metal plate 80 . An annular metal plate 80 covers the core 60 and the case 50 while straddling the first winding 70 and the second winding 71 . That is, the metal plate 80 covers both the first winding 70 and the second winding 71 . The metal plate 80 is separated between the opposing portions between the first winding 70 and the second winding 71 .

As shown in FIGS. 3A, 3B, and 3C, the first winding 70 wound around a portion of the core 60 has both ends 70e formed in through holes of the circuit board 29. It is soldered to the circuit board 29 while protruding from the circuit board 29 through 90 . A second winding 71 wound around the other portion of the core 60 faces the first winding 70 while being separated from the first winding 70 , and both ends 71 e of the circuit board 29 pass through holes (through holes) 91 of the circuit board 29 . It is soldered to the circuit board 29 while protruding from 29 . Specifically, the through holes 90 and 91 are circular.

Ends 70e and 71e of windings 70 and 71 are electrically connected to conductor patterns formed on circuit board 29 by soldering, respectively.
As shown in FIGS. 7A, 7B, and 7C, a metal plate 80 as an annular conductor includes a first metal plate 81 as a first conductor and a second metal plate 81 as a second conductor in the circumferential direction. , and the second metal plate 82 . For the first metal plate 81 and the second metal plate 82, a plate material made of a copper alloy and having a thickness of about 0.5 mm, for example, is used.

The first metal plate 81 has a main body portion 81a that extends linearly in the X direction on the XY plane, and upright portions 81b and 81c that are bent to extend in the Z direction from both ends of the main body portion 81a. The first metal plate 81 is formed by pressing.

The second metal plate 82 has a main body portion 82a that extends linearly in the X direction on the XY plane, and upright portions 82b and 82c that are bent to extend in the Z direction from both ends of the main body portion 82a. The second metal plate 82 is formed by pressing.

The standing portions 81b and 81c of the first metal plate 81 are arranged between the standing portions 82b and 82c on the distal end side of the standing portions 82b and 82c of the second metal plate 82 . The standing portions 82b and 81b are in contact with each other, and the standing portions 82c and 81c are in contact with each other. Thereby, the first metal plate 81 and the second metal plate 82 form an annular shape.

As shown in FIGS. 3A, 3B, and 3C, the first metal plate 81 is arranged so as to be sandwiched between the circuit board 29 and the core 60. As shown in FIGS. The second metal plate 82 is arranged to sandwich the core 60 together with the circuit board 29 . A pair of through holes 92 and 93 (see FIGS. 8A and 8B) are formed in the circuit board 29 . An end portion 81e of the first metal plate 81 and an end portion 82e of the second metal plate 82 protrude from the circuit board 29 through a pair of through holes 92 and 93 (see FIGS. 8A and 8B). It is soldered in place. Each of the through holes 92 and 93 has a rectangular shape. It has a dimension slightly larger than that of the contact body. The standing portions 81b and 81c including the end portion 81e are a pair of first insertion portions that are inserted through the pair of through holes 92 and 93, respectively. The standing portions 82b and 82c including the end portion 82e are a pair of second insertion portions that are inserted through the pair of through holes 92 and 93, respectively.

Here, as shown in FIGS. 9(a), (b), and (c), the end portion 81e of the first metal plate 81 and the end portion 82e of the second metal plate 82 each have a rectangular cross section and are identical to each other. The end portion 81 e of the first metal plate 81 and the end portion 82 e of the second metal plate 82 are in contact with each other when the circuit board 29 is inserted into the through holes 92 and 93 . In this state, the solder S is applied over the entire periphery of the ends 81e and 82e, the short sides of the ends 81e and 82e are soldered to each other, and the ends 81e and 82e are joined together via the solder S. electrically connected. Specifically, as shown in FIGS. 9(a) and 9(c), they are joined at portions S1a, S1b, S2a, and S2b of the solder S. FIG.

Further, the long side portions of the ends 81e and 82e and the circuit board 29 are soldered, and the end 81e of the first metal plate 81 and the end 82e of the second metal plate 82 are connected to the circuit board with solder S interposed therebetween. 29. Specifically, as shown in FIGS. 9(a) and 9(b), they are joined at sites S1c, S1d, S2c, and S2d of solder S. FIG. Thus, the first metal plate 81 and the second metal plate 82 are soldered to the circuit board 29 .

In this way, the standing portions 81b and 81c including the end portion 81e which is the pair of first insertion portions and the standing portions 82b and 82c including the end portion 82e which is the pair of second insertion portions are electrically It is connected to the. The standing portions 81b and 81c including the end portions 81e that are the pair of first insertion portions and the standing portions 82b and 82c that include the end portions 82e that are the pair of second insertion portions are formed into the pair of through holes 92, It protrudes from the circuit board 29 through 93 and is soldered.

As shown in FIGS. 4(a), (b), (c), and FIGS. 8(a), (b), between the metal plate 81 and the pair of windings 70, 71 and between the metal plate 82 and the pair of windings An insulator 110 is interposed between the wires 70 and 71 . That is, between the first metal plate 81 and the first winding 70, between the first metal plate 81 and the second winding 71, between the second metal plate 82 and the first winding 70, and An insulator 110 is interposed between the second metal plate 82 and the second winding 71 .

The insulator 110 is composed of a first insulator 111 and a second insulator 112 . The first insulator 111 is made of a resin film, and the surface of the body portion 81 a of the first metal plate 81 facing the body portion 82 a of the second metal plate 82 , that is, the surface facing the first winding 70 . and the second winding 71 . The first insulator 111 is adhered to the first metal plate 81 .

As shown in FIGS. 7(a), (b), (c) and FIGS. 8(a), (b), the second insulator 112 is made of a resin film, and is the first They are arranged on the surface facing the winding 70 and the surface facing the second winding 71 . Specifically, in the main body portion 82a of the second metal plate 82, the surface facing the main body portion 81a of the first metal plate 81, which is the surface facing the windings 70 and 71, and the standing portion 82b of the second metal plate 82 It is arranged at a portion facing the winding 70 and at a portion facing the winding 71 in the standing portion 82c of the second metal plate 82 . The second insulator 112 is adhered to the second metal plate 82 .

As shown in FIG. 7C, the first insulator 111 and the second insulator 112 are annular.
As shown in FIG. 3C, an insulator 120 is arranged between the circuit board 29 and the main body portion 81a of the first metal plate 81. As shown in FIG. The insulator 120 is made of a resin film and adhered to the surface of the main body 81a of the first metal plate 81 facing the circuit board 29, as shown in FIG. 7(c).

As shown in FIG. 4A , one short side and the other short side of the quadrangular (square square) core 60 are exposed portions that are not covered with the metal plate 80 .
As shown in FIGS. 3B and 3C, heat dissipation grease 130 is arranged on the surface of the metal plate 80 facing the bottom wall portion 15a of the intake housing 15. As shown in FIGS. Thereby, the metal plate 80 is thermally coupled to the suction housing 15 and thus to the housing 14 .

When manufacturing, do the following:
As shown in FIGS. 6A, 6B, and 6C, the core 60 is housed in the case 50, and the first winding 70 and the second winding 71 are wound. As shown in (a), (b), and (c), the first winding 70 and the second winding 71 are sandwiched between the metal plate 80 and the first metal plate 81 and the second metal plate 82. , the end 81e of the first metal plate 81 and the end 82e of the second metal plate 82 are inserted through the through holes 92 and 93 of the circuit board 29, and the first winding 70 and the second 2 are inserted through the through holes 90 and 91 of the circuit board 29 .

At this time, the end 81e of the first metal plate 81, the end 82e of the second metal plate 82, the end 70e of the first winding 70, and the end 71e of the second winding 71 are connected from the circuit board 29 to the circuit. It protrudes from the substrate 29 . Then, the end 81e of the first metal plate 81, the end 82e of the second metal plate 82, the end 70e of the first winding 70, and the second winding 71 protruding from the circuit board 29 are soldered. The end portion 71 e is soldered to the circuit board 29 . The soldering of the windings 70, 71 and the soldering of the metal plates 81, 82 are performed simultaneously (in the same process).

Next, the action will be described.
First, the normal mode (differential mode) will be described with reference to FIGS. 10(a) and 10(b).

As shown in FIG. 10(a), currents i1 and i2 flow through the first winding 70 and the second winding 71, respectively. As a result, magnetic fluxes .phi.1 and .phi.2 are generated in the core 60, but since the magnetic fluxes .phi.1 and .phi.2 are directed in opposite directions, leakage magnetic fluxes .phi.3 and .phi.4 are generated. Here, as shown in FIG. 10(b), an induced current i10 flows in the metal plate 80 in the circumferential direction so as to generate magnetic flux in a direction against the generated leakage magnetic fluxes φ3 and φ4.

In this way, in the metal plate 80, an induced current (eddy current) i10 is generated inside to generate a magnetic flux in a direction against the leakage magnetic flux generated by the energization of the first winding 70 and the second winding 71. flow in the circumferential direction. The induced current flowing in the circumferential direction means that the induced current flows around the core 60 .

In the common mode, energization of the first winding 70 and the second winding 71 causes current to flow in the same direction. Along with this, a magnetic flux is generated in the core 60 in the same direction. In this manner, when a common mode current is applied, a magnetic flux is generated inside the core 60 and little leakage magnetic flux is generated, so the common impedance can be maintained.

Next, the frequency characteristics of the low-pass filter circuit 36 will be described.
If the metal plate 80 made of a conductor does not exist in the common mode choke coil 34, the Q value of the low-pass filter circuit 36 (specifically, the LC resonance circuit including the common mode choke coil 34 and the X capacitor 35) becomes high. . Therefore, normal mode noise having a frequency close to the resonance frequency of the low-pass filter circuit 36 is less likely to be reduced.

On the other hand, in the present embodiment, a metal plate 80 made of a conductor is provided at a position where eddy currents are generated by magnetic lines of force (leakage magnetic fluxes φ3 and φ4) generated in the common mode choke coil 34 . The metal plate 80 made of a conductor is provided at a position through which the leakage magnetic fluxes φ3 and φ4 penetrate. When the leakage magnetic fluxes φ3 and φ4 penetrate, an induced current ( eddy currents). As a result, the metal plate 80 made of a conductor functions to lower the Q value of the low-pass filter circuit 36 . Therefore, the Q value of the low-pass filter circuit 36 is lowered. Therefore, normal mode noise having a frequency near the resonance frequency of the low-pass filter circuit 36 is also reduced by the low-pass filter circuit 36 .

As described above, by adopting the metal shield structure of the belt-shaped and endless metal plate 80 in the common mode choke coil, the common mode choke coil is used in a low-pass filter circuit to reduce common mode noise. In addition, it is possible to positively utilize leakage magnetic flux generated against normal mode current (differential mode current), and to obtain appropriate filter characteristics that also reduce normal mode noise (differential mode noise). That is, by using the belt-shaped and endless metal plate 80, a magnetic flux is generated that opposes the leakage magnetic flux generated when a normal mode current (differential mode current) is applied, and the current flows through the metal plate 80 due to electromagnetic induction and is consumed as heat. be done. Since the metal plate 80 works as a magnetic resistance, a damping effect can be obtained, and a resonance peak generated by the low-pass filter circuit can be suppressed. In addition, when a common mode current is applied, magnetic flux is generated inside the core and little leakage magnetic flux is generated, so common impedance can be maintained.

In the strip-shaped and endless metal plate 80, a current flows inside to generate a magnetic flux in a direction against the leaked magnetic flux, consuming electric power and generating heat. The heat generated by the common mode choke coil 34 is released to the bottom wall portion 15a because the metal plate 80 is thermally bonded to the bottom wall portion 15a. Therefore, the heat generated in the metal plate 80 is released through the heat dissipation grease 130, and the heat dissipation to the heat dissipation surface is excellent.

Conventionally, in order to control the ripple current that flows into and out of the inverter circuit of the electric compressor, as in the automotive electric compressor disclosed in Patent Document 1, by covering the periphery of the winding with a conductive material, the magnetic field line It is possible to take advantage of the fact that eddy currents are generated in the conductive material to counteract changes in . However, in order to improve the assemblability, the ends of one strip material are joined together as tabs projecting outward from the annular portion, but this leads to an increase in size.

In this embodiment, by dividing the metal plate 80 into two parts, the metal plate 80 can be easily assembled in such a manner that the windings 70 and 71 are sandwiched between the two parts. Become. In addition, by soldering the metal plate 80 of the two components through the circuit board 29, the overall size including the windings 70 and 71 and the metal plate 80 can be suppressed.

According to the above embodiment, the following effects can be obtained.
(1) The vehicle-mounted electric compressor 11 includes an inverter device 30 that drives the electric motor 19. The inverter device 30 includes an inverter circuit 31 and a noise reduction section 32. The noise reduction section 32 includes a circuit board. 29, a common mode choke coil 34 mounted on the circuit board 29, and an X capacitor 35 as a smoothing capacitor mounted on the circuit board 29 and forming a low-pass filter circuit 36 together with the common mode choke coil 34. The common mode choke coil 34 includes an annular core 60, a pair of windings 70 and 71 wound around the core 60, and a metal plate 80 as an annular conductor covering both the pair of windings 70 and 71. , provided. The metal plate 80 is composed of a first metal plate 81 as a first conductor which is a metal plate and a second metal plate 82 as a second conductor which is a metal plate. is arranged so as to be sandwiched between the circuit board 29 and the core 60 , and the second metal plate 82 as a second conductor is arranged so as to sandwich the core 60 together with the circuit board 29 . A pair of through holes 92 and 93 are formed in the circuit board 29, and a first metal plate 81 as a first conductor is formed as a pair of first insertion portions that are inserted through the pair of through holes 92 and 93, respectively. It has standing portions 81b and 81c including an end portion 81e. A second metal plate 82 as a second conductor has upright portions 82b and 82c including end portions 82e as a pair of second insertion portions that are inserted through the pair of through holes 92 and 93, respectively. The standing portions 81b and 81c including the end portions 81e as a pair of first insertion portions and the standing portions 82b and 82c including the end portions 82e as a pair of second insertion portions are electrically connected to each other. .

Therefore, since the annular metal plate 80 is divided into the first metal plate 81 and the second metal plate 82 in the circumferential direction, the core 60 including the pair of windings 70 and 71 is assembled. Improves adhesion. Specifically, the first metal plate 81 as the first conductor, the core 60, and the second metal plate 82 as the second conductor are assembled to the circuit board 29 so as to be inserted through the pair of through holes 92 and 93 in this order. Thus, it is possible to easily assemble a structure in which the ring-shaped conductor covers the core while ensuring the clearance between the conductor and the common mode choke coil as designed. As a result, it is possible to improve the assemblability.

(2) The standing portions 81b and 81c including the end portions 81e as the pair of first insertion portions and the standing portions 82b and 82c including the end portions 82e as the pair of second insertion portions are connected to the pair of through holes 92. , 93 protruding from the circuit board 29 and soldered. Therefore, both ends of the first conductor and both ends of the second conductor can be soldered in the same process as the common mode choke coil 34 and the circuit board 29 are soldered. As a result, it is possible to improve the assemblability while stabilizing the electrical connection.

(3) Since the insulator 110 is interposed between the first metal plate 81 and the pair of windings 70, 71 and between the second metal plate 82 and the pair of windings 70, 71, the metal plate 80 and the windings 70, 71 can be easily insulated.

(4) The insulator 110 is arranged on the surface of the first metal plate 81 facing the pair of windings 70 and 71, and faces the pair of windings 70 and 71 of the second metal plate 82. The first insulator 111 and the second insulator 112 form an annular shape. Thereby, the insulation between the metal plate 80 and the windings 70 and 71 can be ensured.

(5) The first metal plate 81 and the second metal plate 82 are soldered to the circuit board 29 . Therefore, since the first metal plate 81 and the second metal plate 82 are fixed to the circuit board 29, the vibration resistance is excellent.

Embodiments are not limited to the above, and may be embodied as follows, for example.
O The metal plate 80 may be made of an aluminum plate, a brass plate, a stainless steel plate, or the like, in addition to the copper plate. Moreover, not only non-magnetic metals such as copper but also magnetic metals may be used. Here, if a magnetic metal such as iron is used for the metal plate 80, magnetic flux is generated as the induced current flows, which may have an adverse effect. Therefore, a non-magnetic metal is preferable.

O Since the conductor has a split structure, the thickness of the first conductor may be made thicker than that of the second conductor in order to improve heat dissipation.
The first metal plate 81 and the second metal plate 82 may be electrically connected not only through the solder S but also by direct contact between the standing portions 81b, 81c and the standing portions 82b, 82c. . Moreover, even if the first metal plate 81 and the second metal plate 82 are electrically connected only by direct contact between the standing portions 81b, 81c and the standing portions 82b, 82c without the solder S interposed therebetween. good.

Alternatively, a material having higher thermal conductivity than that of the second conductor may be selected for the first conductor in order to improve heat dissipation. For example, the first conductor is a copper alloy and the second conductor is also a copper alloy, and the copper alloy material of the first conductor has a higher thermal conductivity than the copper alloy material of the second conductor. .

Alternatively, the thickness of the first conductor may be made thicker than that of the second conductor in order to improve heat dissipation, and a material having a higher thermal conductivity than that of the second conductor may be selected for the first conductor.
In this way, in the case of a component having a uniform plate thickness, it is difficult to dissipate the heat generated by the eddy current on the surface that is not in contact with the heat radiating member (the upper surface in FIG. 3(c)). In other words, because of the two-part structure, the plate thickness and material itself of the first metal plate 81 not in contact with the heat dissipating member are changed according to the required heat dissipation specifications, for example, with respect to the second metal plate 82 in contact with the heat dissipating member. It is possible to improve the robustness against heat dissipation.

The insulation between the metal plates 81, 82 and the windings 70, 71 may be provided by insulating coating instead of the insulators 111, 112 made of resin. For example, a resin coating film may be formed on the surfaces of the metal plates 81 and 82 at locations facing the windings 70 and 71 .

The insulation between the metal plates 81 and 82 and the windings 70 and 71 is replaced by the insulators 111 and 112 made of resin. It may be covered with an insulating film.

(circle) when the space|gap of sufficient distance can be ensured between the 1st metal plate 81 and windings 70 and 71, the 1st insulator 111 can be made unnecessary. Similarly, it is possible to eliminate the second insulator 112 if a sufficient gap can be secured between the second metal plate 82 and the windings 70 , 71 . Further, if a sufficient gap can be secured between the circuit board 29 and the main body portion 81a of the first metal plate 81, the insulator 120 can be omitted.

DESCRIPTION OF SYMBOLS 11... Vehicle electric compressor, 18... Compression part, 19... Electric motor, 29... Circuit board, 30... Inverter apparatus, 31... Inverter circuit, 32... Noise reduction part, 34... Common mode choke coil, 35... X capacitor , 60... core, 70, 71... pair of windings, 80... metal plate, 81... first metal plate, 81a... standing portion, 81b... standing portion, 81e... end, 82... second metal plate, 82a...upright portion, 82b...upright portion, 82e...end portion, 92, 93...through hole, 110...insulator, 111...first insulator, 112...second insulator.

Claims (5)

a compression section for compressing a fluid;
an electric motor that drives the compression unit;
and an inverter device that drives the electric motor,
The inverter device
an inverter circuit;
a noise reduction unit that is provided on the input side of the inverter circuit and reduces common mode noise and normal mode noise contained in the direct current that is input to the inverter circuit,
The noise reduction unit is
a circuit board;
a common mode choke coil mounted on the circuit board;
a smoothing capacitor mounted on the circuit board and forming a low-pass filter circuit together with the common mode choke coil,
The common mode choke coil is
an annular core;
a pair of windings wound around the core;
and an annular conductor covering both of the pair of windings,
The conductor comprises a first conductor that is a metal plate and a second conductor that is a metal plate,
The first conductor is arranged to be sandwiched between the circuit board and the core,
The second conductor is arranged to sandwich the core together with the circuit board,
A pair of through holes are formed in the circuit board,
The first conductor has a pair of first insertion portions that are respectively inserted into the pair of through holes,
The second conductor has a pair of second insertion portions that are respectively inserted into the pair of through holes,
An on-vehicle electric compressor, wherein the pair of first insertion portions and the pair of second insertion portions are electrically connected to each other. 2. The in-vehicle device according to claim 1, wherein the pair of first insertion portions and the pair of second insertion portions are soldered in a state of protruding from the circuit board through the pair of through holes. electric compressor. 3. An insulator according to claim 1, wherein an insulator is interposed between said first conductor and said pair of windings and between said second conductor and said pair of windings. Automotive electric compressor. The insulator includes a first insulator arranged on a surface of the first conductor facing the pair of windings and a second insulator arranged on a surface of the second conductor facing the pair of windings. consists of a body and
4. The vehicle-mounted electric compressor according to claim 3, wherein the first insulator and the second insulator are annular. 5. The vehicle-mounted electric compressor according to claim 1, wherein the first conductor and the second conductor are soldered to the circuit board.

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