Electric compressor

Abstract

To improve a heat dissipation of a conductive body.SOLUTION: A second metal plate 62 includes: a second metal plate main body part 62a; and a pair of extension parts 62b. The second metal plate main body part 62a is arranged to a first metal plate 61 so as to nip a pair of windings 51. The pair of extension parts 62b is extended toward a housing 14 from the second metal plate main body part 62a. At least the second metal plate 62 of the first metal plate 61 and the second metal plate 62 is thermally connected to the housing 14. The first metal plate 61 is thermally connected to the second metal plate 62. In at least one of an electric resistance value and a thermal resistance value in a current path of a dielectric current, since the second metal plate 62 is smaller than the first metal plate 61, a thermal transmission path reached from the second metal plate main body part 62a to the housing 14 via each extension part 62b is easily secured. Thus, a heat generated from the second metal plate 62 is efficiently discharged to the housing 14.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to an electric compressor.

Background Art

[0002] An electric compressor includes a compression section, a motor, and an inverter device. The compression section compresses a fluid. The motor drives the compression section. The inverter device is housed in a metal housing. The inverter device drives the motor.

[0003] The inverter device includes an inverter circuit, a noise reduction section, and a circuit board. The inverter circuit converts DC power into AC power. The noise reduction section is provided on the input side of the inverter circuit. The noise reduction section reduces common mode noise and normal mode noise included in the DC power input to the inverter circuit. The inverter circuit and the noise reduction section are mounted on the circuit board. The noise reduction section includes a common mode choke coil and a smoothing capacitor. The smoothing capacitor forms a low-pass filter together with the common mode choke coil.

[0004] The common mode choke coil includes an annular core, a pair of windings, and an annular conductor. The pair of windings is wound around the core. The conductor covers both of the pair of windings.

[0005] For example, in Patent Document 1, the conductor is divided into a first metal plate and a second metal plate that form an annulus. Induced currents flow in the circumferential direction in the annulus in the first metal plate and the second metal plate so as to oppose changes in leakage magnetic flux from the core.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Summary of the Invention

[0007] In the configuration of Patent Document 1, the first metal plate has a main body and a pair of upright portions formed by bending from both ends of the main body. The second metal plate has a main body and a pair of upright portions formed by bending from both ends of the main body. A pair of upright portions of the second metal plate is provided between the pair of upright portions of the first metal plate and welded to each other.

[0008] However, the electrical resistance of the first metal plate is greater than that of the second metal plate. Therefore, heat tends to accumulate in the second metal plate due to, for example, the heat generated by the induced current flowing through the welded area and the heat generated by the induced current flowing through the second metal plate. Thus, it is desirable to dissipate the heat from the second metal plate into the housing. [Means for solving the problem]

[0009] An electric compressor that solves the above problems comprises a compression unit for compressing a fluid, a motor for driving the compression unit, and an inverter device housed in a metal housing for driving the motor, wherein the inverter device comprises an inverter circuit for converting DC power to AC power, a noise reduction unit provided on the input side of the inverter circuit for reducing common-mode noise and normal-mode noise contained in the DC power input to the inverter circuit, and a circuit board on which the inverter circuit and the noise reduction unit are mounted, wherein the noise reduction unit comprises a common-mode choke coil and a smoothing capacitor that, together with the common-mode choke coil, constitutes a low-pass filter, wherein the common-mode choke coil comprises an annular core, a pair of windings wound around the core, and an annular conductor covering both of the pair of windings. The conductor is divided into a first metal plate and a second metal plate forming the annular shape, and an induced current flows in the circumferential direction of the annular shape between the first metal plate and the second metal plate in order to resist changes in leakage magnetic flux from the core, the circuit board is arranged with respect to the housing with the common mode choke coil in between, the second metal plate has a main body portion arranged with respect to the first metal plate with the pair of windings in between, and a pair of extending portions extending from the main body portion toward the housing, at least the second metal plate is thermally connected to the housing, and the first metal plate is thermally connected to the second metal plate, and at least one of the electrical resistance value and thermal resistance value in the current path of the induced current is smaller for the second metal plate than for the first metal plate.

[0010] According to this, the heat from the second metal plate can be dissipated to the housing. At this time, at least one of the electrical resistance and thermal resistance values ​​in the current path of the induced current is smaller for the second metal plate than for the first metal plate. Therefore, a heat transfer path from the main body of the second metal plate to the housing via each extended portion is easily secured. Consequently, the heat generated from the second metal plate can be efficiently dissipated to the housing. As a result, the heat dissipation performance of the conductor can be improved.

[0011] In the above-described electric compressor, the housing preferably has a pair of recesses, and the tip of each extension portion is inserted into each of the recesses. This allows for an increase in the heat transfer paths between each extended portion and the housing. Therefore, the heat generated from the second metal plate can be dissipated to the housing more efficiently.

[0012] In the above-described electric compressor, the first metal plate may have a pair of upright portions that stand up toward the housing, and each of the upright portions may be inserted into the respective recesses and thermally connected to the housing.

[0013] According to this design, heat generated from the first metal plate is more easily transferred to the housing via each upright portion. Therefore, heat generated from the first metal plate can be efficiently dissipated to the housing. As a result, the heat dissipation performance of the conductor can be further improved.

[0014] In the electric compressor described above, the conductor is provided with a plurality of joints that metallically join the tip portion of each extended portion to each upright portion, and the joints are preferably arranged inside each recess and thermally connected to the housing.

[0015] This design allows heat generated from each joint to be more easily transferred to the housing. Therefore, heat generated from each joint can be efficiently dissipated to the housing. As a result, the heat dissipation performance of the conductor can be further improved. In addition, the heat dissipation from the second metal plate to the housing can be suppressed from being hindered by each joint. [Effects of the Invention]

[0016] According to this invention, it is possible to improve the heat dissipation performance of a conductor. [Brief explanation of the drawing]

[0017] [Figure 1] This is a side cross-sectional view of an electric compressor in an embodiment. [Figure 2] It is a circuit diagram showing the electrical configuration of an electric compressor. [Figure 3] It is an exploded perspective view of a common mode choke coil. [Figure 4] It is a cross-sectional view showing a part of the electric compressor.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, an embodiment in which an electric compressor is embodied will be described according to FIGS. 1 to 4. The electric compressor of this embodiment is used, for example, in a vehicle air conditioner. <Vehicle air conditioner 10> As shown in FIG. 1, the vehicle air conditioner 10 includes an electric compressor 11 and an external refrigerant circuit 12. The external refrigerant circuit 12 supplies refrigerant as a fluid to the electric compressor 11. The external refrigerant circuit 12 has, for example, a heat exchanger, an expansion valve, and the like. The vehicle air conditioner 10 performs heating and cooling inside the vehicle by compressing the refrigerant by the electric compressor 11 and performing heat exchange and expansion of the refrigerant by the external refrigerant circuit 12.

[0019] The vehicle air conditioner 10 includes an air conditioning ECU 13. The air conditioning ECU 13 controls the entire 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, and the like. Then, the air conditioning ECU 13 transmits various commands such as ON / OFF commands to the electric compressor 11 based on parameters such as the vehicle interior temperature and the set temperature of the car air conditioner.

[0020] <Basic configuration of the electric compressor 11> The electric compressor 11 includes a housing 14. The housing 14 is formed of a heat-conductive metal material such as aluminum, for example. Therefore, the housing 14 is made of metal. The housing 14 is grounded to the vehicle body.

[0021] The housing 14 has an intake housing 15 and a discharge housing 16. The intake housing 15 and the discharge housing 16 are assembled to each other. The intake housing 15 has a plate-shaped end wall 15a and a cylindrical peripheral wall 15b. The peripheral wall 15b extends cylindrically from the outer peripheral portion of the end wall 15a. The discharge housing 16 is assembled to the intake housing 15 in a state of closing the opening of the intake housing 15. Thereby, an internal space is formed in the housing 14.

[0022] The housing 14 has a suction port 14a. Refrigerant is sucked into the suction port 14a from the external refrigerant circuit 12. Therefore, refrigerant is sucked into the housing 14. The suction port 14a is formed in the peripheral wall 15b of the intake housing 15. The suction port 14a is formed at a portion of the peripheral wall 15b of the intake housing 15 closer to the end wall 15a than the discharge housing 16. The housing 14 has a discharge port 14b. The discharge port 14b discharges the refrigerant to the external refrigerant circuit 12. The discharge port 14b is formed in the discharge housing 16.

[0023] The electric compressor 11 includes a rotating shaft 17, a compression part 18, and a motor 19. The rotating shaft 17, the compression part 18, and the motor 19 are accommodated in the housing 14. The rotating shaft 17 is supported in a rotatable state with respect to the housing 14. The rotating shaft 17 is arranged in the housing 14 in a state where the axial direction of the rotating shaft 17 coincides with the axial direction of the peripheral wall 15b.

[0024] The compression part 18 is accommodated in the intake housing 15. The compression part 18 is, for example, of a scroll type composed of a fixed scroll (not shown) fixed in the intake housing 15 and a turning scroll (not shown) arranged to face the fixed scroll. The compression part 18 is arranged in the intake housing 15 at a position closer to the discharge port 14b than the suction port 14a. The compression part 18 is connected to the rotating shaft 17. The compression part 18 is driven by the rotation of the rotating shaft 17 to compress the refrigerant.

[0025] The motor 19 is housed within the intake housing 15. The motor 19 is positioned between the compression section 18 and the end wall 15a within the intake housing 15. The motor 19 includes a rotor 20 and a stator 21. The stator 21 includes a cylindrical stator core 22 and u-phase coils 23u, v-phase coils 23v, and w-phase coils 23w.

[0026] The u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w are each wound around the stator core 22. The u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w are connected in a Y configuration, for example. However, the connection configuration of the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w is not limited to a Y configuration and is arbitrary. The connection configuration of the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w may be, for example, a delta connection.

[0027] The rotor 20 is cylindrical in shape. The rotor 20 is fixed to the rotating shaft 17. This configuration allows the rotating shaft 17 to rotate integrally with the rotor 20. The stator 21 is fixed to the peripheral wall 15b of the intake housing 15. The rotor 20 and the stator 21 are facing each other in the radial direction of the rotating shaft 17.

[0028] The rotor 20 rotates when the u-phase coil 23u, v-phase coil 23v, and w-phase coil 23w are energized in a predetermined pattern. As the rotor 20 rotates, the rotating shaft 17 rotates. This drives the compression unit 18. Therefore, the motor 19 drives the compression unit 18. The refrigerant flowing through the external refrigerant circuit 12 is then drawn into the housing 14 from the intake port 14a. The compression unit 18 compresses the refrigerant drawn into the housing 14. The compressed refrigerant is discharged from the discharge port 14b to the external refrigerant circuit 12.

[0029] The electric compressor 11 is equipped with an inverter device 30. The inverter device 30 drives the motor 19. The housing 14 has an inverter cover 31. The inverter cover 31 is made of a metal material such as aluminum. The inverter cover 31 is attached to the end wall 15a of the intake housing 15 via bolts 32. The end wall 15a of the intake housing 15 and the inverter cover 31 form an inverter housing chamber S1. The inverter device 30 is housed in the inverter housing chamber S1. Therefore, the inverter device 30 is housed in the metal housing 14.

[0030] The electric compressor 11 is equipped with a connector 27. The connector 27 is electrically connected to a power storage device 28 mounted on the vehicle. The connector 27 is located on the inverter cover 31. The connector 27 protrudes from the inverter cover 31. The power storage device 28 is a power source that supplies power to equipment mounted on the vehicle. The power storage device 28 is a DC power source. The power storage device 28 is, for example, a secondary battery or a capacitor.

[0031] The inverter device 30 has a circuit board 34. The circuit board 34 is housed in the inverter housing chamber S1. The circuit board 34 is positioned opposite the end wall 15a at a predetermined distance in the axial direction of the rotation shaft 17. The circuit board 34 is housed in the inverter housing chamber S1 with its thickness direction aligned with the axial direction of the rotation shaft 17.

[0032] The inverter device 30 comprises an inverter circuit 35 and a noise reduction unit 36. The inverter circuit 35 converts DC power to AC power. The noise reduction unit 36 ​​is provided on the input side of the inverter circuit 35. The noise reduction unit 36 ​​reduces common-mode noise and normal-mode noise contained in the DC power before it is input to the inverter circuit 35. The inverter circuit 35 and the noise reduction unit 36 ​​are mounted on a circuit board 34. Therefore, the housing 14 accommodates the inverter circuit 35 and the noise reduction unit 36.

[0033] <Inverter circuit 35> As shown in Figure 2, the inverter circuit 35 has two connection lines EL1 and EL2. The inverter circuit 35 has u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 23u. The inverter circuit 35 has v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 23v. The inverter circuit 35 has w-phase switching elements Qw1 and Qw2 corresponding to the w-phase coil 23w. Each switching element Qu1 to Qw2 is a power switching element such as an IGBT. Each switching element Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2 is connected to a freewheeling diode Du1, Du2, Dv1, Dv2, Dw1, and Dw2, respectively.

[0034] Each u-phase switching element Qu1 and Qu2 are connected in series. The connection between each u-phase switching element Qu1 and Qu2 is made to the u-phase coil 23u. The series connection of each u-phase switching element Qu1 and Qu2 is electrically connected to both connection lines EL1 and EL2.

[0035] Each v-phase switching element Qv1 and Qv2 is connected in series. The connection between each v-phase switching element Qv1 and Qv2 is made to the v-phase coil 23V. The series connection of each v-phase switching element Qv1 and Qv2 is electrically connected to both connection lines EL1 and EL2.

[0036] Each w-phase switching element Qw1 and Qw2 is connected in series. The connection between each w-phase switching element Qw1 and Qw2 is made to the w-phase coil 23w. The series connection of each w-phase switching element Qw1 and Qw2 is electrically connected to both connection lines EL1 and EL2.

[0037] The inverter device 30 includes a control unit 37. The control unit 37 controls the switching operation of each switching element Qu1 to Qw2. The control unit 37 can be implemented, for example, by one or more dedicated hardware circuits and / or one or more processors (control circuits) that operate according to a computer program (software). The processor includes a CPU and memory such as RAM and ROM, and the memory stores, for example, program code or instructions configured to cause the processor to execute various processes. Memory, or computer-readable media, includes any available media that can be accessed by a general-purpose or dedicated computer.

[0038] The control unit 37 is electrically connected to the air conditioning ECU 13 via the connector 27. Based on commands from the air conditioning ECU 13, the control unit 37 periodically turns each switching element Qu1 to Qw2 ON / OFF. More specifically, based on commands from the air conditioning ECU 13, the control unit 37 performs pulse width modulation (PWM) control on each switching element Qu1 to Qw2. More specifically, the control unit 37 generates a control signal using a carrier signal and a command voltage value signal (comparison signal). Then, the control unit 37 converts DC power to AC power by controlling the ON / OFF state of each switching element Qu1 to Qw2 using the generated control signal.

[0039] <Noise reduction unit 36> The noise reduction unit 36 ​​includes a common-mode choke coil 38 and a smoothing capacitor 39. The smoothing capacitor 39, together with the common-mode choke coil 38, constitutes a low-pass filter 40. The low-pass filter 40 is provided on connection lines EL1 and EL2. Circuit-wise, the low-pass filter 40 is provided between the connector 27 and the inverter circuit 35. The common-mode choke coil 38 is provided on both connection lines EL1 and EL2.

[0040] The smoothing capacitor 39 is located on the inverter circuit 35 side relative to the common mode choke coil 38. The smoothing capacitor 39 is an X capacitor connected in parallel to the inverter circuit 35. The smoothing capacitor 39 is electrically connected to both connection lines EL1 and EL2. The common mode choke coil 38 and the smoothing capacitor 39 constitute an LC resonant circuit. Therefore, the low-pass filter 40 of this embodiment is an LC resonant circuit including the common mode choke coil 38.

[0041] The noise reduction unit 36 ​​is equipped with two Y capacitors 41. The two Y capacitors 41 are connected in series. The space between the two Y capacitors 41 is grounded to the vehicle body via the housing 14. The two Y capacitors 41 are located on the inverter circuit 35 side relative to the common mode choke coil 38. The two Y capacitors 41 are connected in parallel to the common mode choke coil 38. The two Y capacitors 41 are connected in parallel to the smoothing capacitor 39. The two Y capacitors 41 are located between the common mode choke coil 38 and the smoothing capacitor 39.

[0042] The common-mode choke coil 38 suppresses the transmission of high-frequency noise generated on the vehicle side to the inverter circuit 35 of the electric compressor 11. The common-mode choke coil 38 utilizes its leakage inductance as the normal inductance. As a result, the common-mode choke coil 38 is used as the L component in the low-pass filter (LC filter) 40 for removing normal-mode noise (differential-mode noise). In other words, the common-mode choke coil 38 can handle both common-mode noise and normal-mode noise (differential-mode noise). Therefore, in the electric compressor 11 of this embodiment, instead of using separate choke coils for common-mode and normal-mode (differential-mode) noise, the common-mode choke coil 38 handles both modes of noise.

[0043] <Common mode choke coil 38> As shown in Figure 3, the common mode choke coil 38 comprises a core 50 and a pair of windings 51. The core 50 is annular in shape. The core 50 is made of a ferromagnetic material. For example, the core 50 is made of a ferrite core. The core 50 has a pair of straight sections 52 and a pair of connecting sections 53.

[0044] Each straight section 52 is, for example, a rectangular prism. Each straight section 52 extends parallel to each other. Each straight section 52 is arranged such that the directions in which the axes of each straight section 52 extend coincide with each other. Each straight section 52 is facing each other while moving away from each other. Each winding 51 is wound around each straight section 52. Each winding 51 is wound around the core 50. Each winding 51 faces each other.

[0045] Each connecting portion 53 is, for example, rectangular prism-shaped. One of a pair of connecting portions 53 connects the first ends of each straight portion 52. The other of a pair of connecting portions 53 connects the second ends of each straight portion 52. A portion of each winding 51 is wound around each connecting portion 53. In addition, resin members (not shown) are provided between the core 50 and each winding 51 to ensure insulation between the core 50 and each winding 51.

[0046] As shown in Figure 4, the common mode choke coil 38 is positioned between the circuit board 34 and the end wall 15a of the intake housing 15. Therefore, the circuit board 34 is positioned with the common mode choke coil 38 in between the housing 14. The common mode choke coil 38 is positioned such that the direction in which the axes of each straight section 52 extend is perpendicular to the opposing direction of the circuit board 34 and the end wall 15a of the intake housing 15.

[0047] The common mode choke coil 38 is mounted on the outer surface of the end wall 15a of the intake housing 15. Therefore, the outer surface of the end wall 15a of the intake housing 15 is the mounting surface 54 on which the common mode choke coil 38 is mounted. The common mode choke coil 38 is mounted on the mounting surface 54 of the housing 14. The mounting surface 54 has a pair of recesses 55.

[0048] As shown in Figure 3, each winding 51 wound around each connecting portion 53 is led out as a lead portion 56. Then, as shown in Figure 4, each lead portion 56 is soldered to the circuit board 34, for example. In this way, the common mode choke coil 38 is electrically connected to the circuit board 34.

[0049] As shown in Figures 3 and 4, the common mode choke coil 38 is equipped with a conductor 60. The conductor 60 is annular in shape and covers both of the pair of windings 51. In addition, resin members (not shown) are provided between the conductor 60 and each winding 51 to ensure insulation between the conductor 60 and each winding 51.

[0050] The conductor 60 includes a first metal plate 61 and a second metal plate 62. The conductor 60 is divided into a first metal plate 61 and a second metal plate 62 that form an annular shape. The first metal plate 61 is made of, for example, copper. The second metal plate 62 is made of, for example, phosphor bronze. Therefore, the second metal plate 62 is made of a material with a higher thermal conductivity than the first metal plate 61.

[0051] The thickness T1 of the first metal plate 61 is constant. The thickness T2 of the second metal plate 62 is constant. The thickness T1 of the first metal plate 61 is thinner than the thickness T2 of the second metal plate 62. Therefore, the cross-sectional area of ​​the first metal plate 61 in the thickness direction is smaller than the cross-sectional area of ​​the second metal plate 62 in the thickness direction.

[0052] The first metal plate 61 has a first metal plate body portion 61a and a pair of upright portions 61b. The first metal plate body portion 61a is rectangular and flat. Each upright portion 61b is rectangular and flat. Each upright portion 61b rises from both ends of the first metal plate body portion 61a in the longitudinal direction. Therefore, the pair of upright portions 61b rise from the first metal plate body portion 61a. Each upright portion 61b rises from both ends of the first metal plate body portion 61a in the longitudinal direction, with the direction in which it rises from the first metal plate body portion 61a coinciding with the thickness direction of the first metal plate body portion 61a. The pair of upright portions 61b extend parallel to each other. The pair of upright portions 61b extend from the first metal plate body portion 61a toward the intake housing 15. Therefore, each upright portion 61b rises toward the housing 14. The width of the first metal plate body portion 61a is the same as the width of each upright portion 61b. The first metal plate 61 is formed by press-forming a single metal plate.

[0053] As shown in Figure 4, the first metal plate body 61a is joined to the mounting surface 54 via adhesive 63. The first metal plate body 61a is thermally connected to the mounting surface 54 via adhesive 63. Therefore, the first metal plate 61 is thermally connected to the mounting surface 54. The first metal plate body 61a covers the portion of the pair of windings 51 that is on the mounting surface 54 side. Therefore, the first metal plate 61 covers the portion of the pair of windings 51 that is on the mounting surface 54 side.

[0054] As shown in Figures 3 and 4, the second metal plate 62 has a second metal plate body portion 62a as the main body portion and a pair of extension portions 62b. The second metal plate body portion 62a is rectangular flat plate. Each extension portion 62b is rectangular flat plate. As shown in Figure 4, the pair of extension portions 62b extend from the second metal plate body portion 62a toward the end wall 15a of the suction housing 15. Each extension portion 62b extends from both ends of the second metal plate body portion 62a in the longitudinal direction. Each extension portion 62b extends from both ends of the second metal plate body portion 62a in the longitudinal direction, with the direction of extension from the second metal plate body portion 62a coinciding with the thickness direction of the second metal plate body portion 62a. The pair of extension portions 62b extend parallel to each other. The width of the second metal plate body portion 62a is the same as the width of each extension portion 62b. The width of the second metal plate body portion 62a is the same as the width of the first metal plate body portion 61a. The width of each extended portion 62b is the same as the width of each upright portion 61b. The second metal plate 62 is formed by press-forming a single metal plate.

[0055] The second metal plate body 62a covers the portion of the pair of windings 51 opposite to the mounting surface 54. Therefore, the second metal plate 62 covers the portion of the pair of windings 51 opposite to the mounting surface 54. The second metal plate body 62a is positioned with the pair of windings 51 sandwiched between the first metal plate 61. The pair of extensions 62b each cover the portion of the pair of windings 51 opposite to the adjacent portions.

[0056] The tip of each extended portion 62b is joined to each upright portion 61b. Therefore, the conductor 60 has a plurality of joints 64 that metallically join the tip of each extended portion 62b to each upright portion 61b. Each extended portion 62b and each upright portion 61b are welded together, for example, by resistance welding. Therefore, the joints 64 are the parts that weld each extended portion 62b and each upright portion 61b to each other.

[0057] Thus, the pair of extended portions 62b are electrically connected to the first metal plate 61. Therefore, the first metal plate 61 is thermally connected to the second metal plate 62. The conductor 60 is formed in a strip shape and endlessly, as the tips of each extended portion 62b and each upright portion 61b are joined via joints 64.

[0058] The tip of each extension portion 62b and each upright portion 61b are inserted into each recess 55, respectively. Adhesive 65 is filled into each recess 55. The tip of each extension portion 62b and each upright portion 61b are thermally connected to the inner surface of the recess 55 via the adhesive 65. Therefore, the tip of each extension portion 62b is inserted into each recess 55 and thermally connected to the inner surface of the recess 55. Thus, the pair of extension portions 62b are thermally connected to the housing 14. Of the first metal plate 61 and the second metal plate 62, at least the second metal plate 62 is thermally connected to the housing 14. The pair of upright portions 61b are inserted into each recess 55 and thermally connected to the inner surface of the recess 55. Therefore, each upright portion 61b is inserted into each recess 55 and thermally connected to the housing 14. Each joint portion 64 is positioned inside each recess 55 and thermally connected to the housing 14.

[0059] [Effect of the Embodiment] Next, the operation of this embodiment will be described. When the pair of windings 51 are energized, current flows through each winding 51. This generates magnetic flux in the core 50, as well as leakage flux. At this point, an induced current flows circumferentially within the conductor 60 to generate magnetic flux in a direction that opposes the leakage flux. In the first metal plate 61 and the second metal plate 62, an induced current flows circumferentially in a ring shape to oppose the change in leakage flux from the core 50. In this way, an induced current flows circumferentially within the conductor 60 to generate magnetic flux in a direction that opposes the leakage flux generated when each winding 51 is energized. The induced current flows around the core 50. When the induced current flowing through the conductor 60 is converted into thermal energy, the conductor 60 acts as a magnetic resistance, resulting in a damping effect. As a result, the resonance peak generated by the low-pass filter 40 is suppressed.

[0060] The conductor 60 is divided circumferentially into a first metal plate 61 and a second metal plate 62. The cross-sectional area of ​​the first metal plate 61 in the thickness direction is smaller than the cross-sectional area of ​​the second metal plate 62 in the thickness direction. Therefore, the electrical resistance of the first metal plate 61 is greater than that of the second metal plate 62. Consequently, the amount of heat generated at the first metal plate 61 is greater than the amount of heat generated at the second metal plate 62. Therefore, the heat generated from the conductor 60 tends to concentrate at the first metal plate 61. At this time, since the first metal plate 61 is thermally connected to the mounting surface 54, the heat generated at the first metal plate 61 is efficiently dissipated to the housing 14. As a result, the heat generated from the conductor 60 is efficiently dissipated to the housing 14.

[0061] Furthermore, a considerable amount of heat is also generated in the second metal plate 62. The heat generated from the main body portion 62a of the second metal plate is dissipated to the housing 14 via each extended portion 62b. At this time, the cross-sectional area of ​​the first metal plate 61 in the thickness direction is smaller than the cross-sectional area of ​​the second metal plate 62 in the thickness direction. In other words, the cross-sectional area of ​​the second metal plate 62 in the thickness direction is larger than the cross-sectional area of ​​the first metal plate 61 in the thickness direction. Therefore, at least one of the electrical resistance value and thermal resistance value in the current path of the induced current is smaller for the second metal plate 62 than for the first metal plate 61. For this reason, a heat transfer path from the main body portion 62a of the second metal plate to the housing 14 via each extended portion 62b is easily secured. In particular, the tip of each extended portion 62b is inserted into each recess 55 and thermally connected to the inner surface of the recess 55. Therefore, compared to, for example, the case where the tip of each extended portion 62b is thermally connected to the mounting surface 54, the heat transfer path between each extended portion 62b and the housing 14 is increased. Consequently, the heat generated from the second metal plate 62 is efficiently dissipated to the housing 14.

[0062] [Effects of the Embodiment] The above embodiment can be achieved to obtain the following effects. (1) The second metal plate 62 has a second metal plate body portion 62a and a pair of extending portions 62b. The second metal plate body portion 62a is positioned relative to the first metal plate 61 with a pair of windings 51 in between. The pair of extending portions 62b extend from the second metal plate body portion 62a toward the housing 14. Of the first metal plate 61 and the second metal plate 62, at least the second metal plate 62 is thermally connected to the housing 14. The first metal plate 61 is thermally connected to the second metal plate 62. This allows heat from the second metal plate 62 to be dissipated to the housing 14. At this time, at least one of the electrical resistance value and thermal resistance value in the current path of the induced current is smaller for the second metal plate 62 than for the first metal plate 61. Therefore, a heat transfer path from the second metal plate body portion 62a to the housing 14 via each of the extending portions 62b is easily secured. Therefore, the heat generated from the second metal plate 62 can be efficiently dissipated to the housing 14. As a result, the heat dissipation performance of the conductor 60 can be improved.

[0063] (2) The housing 14 has a pair of recesses 55. The tip of each extension 62b is inserted into each recess 55. This increases the heat transfer path between each extension 62b and the housing 14 compared to, for example, the case where the tip of each extension 62b is thermally connected to the mounting surface 54 of the housing 14. Therefore, the heat generated from the second metal plate 62 can be dissipated to the housing 14 more efficiently.

[0064] (3) The first metal plate 61 has a pair of upright portions 61b. The pair of upright portions 61b stand upright toward the housing 14. Each upright portion 61b is inserted into each recess 55 and is thermally connected to the housing 14. As a result, the heat generated from the first metal plate 61 is also transferred to the inner surface of the recess 55 via each upright portion 61b. Therefore, the heat generated from the first metal plate 61 can be efficiently dissipated to the housing 14. As a result, the heat dissipation performance of the conductor 60 can be further improved.

[0065] (4) The conductor 60 is provided with a plurality of joints 64 that metallically join the tip of each extended portion 62b to each upright portion 61b. Each joint 64 is positioned inside each recess 55 and is thermally connected to the housing 14. This makes it easier for the heat generated from each joint 64 to be transferred to the housing 14. Therefore, the heat generated from each joint 64 can be efficiently dissipated to the housing 14. As a result, the heat dissipation performance of the conductor 60 can be further improved. In addition, it is possible to suppress the obstruction of heat dissipation from the second metal plate 62 to the housing 14 by each joint 64.

[0066] (5) The second metal plate 62 is made of a material with a higher thermal conductivity than the first metal plate 61. For example, consider the case where the second metal plate 62 is made of a material with the same thermal conductivity as the first metal plate 61, or a material with a lower thermal conductivity than the first metal plate 61. Compared to such cases, the heat generated from the second metal plate 62 can be dissipated to the housing 14 more efficiently.

[0067] [Example of changes] The above embodiment can be implemented with the following modifications. The above embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0068] ○ In this embodiment, for example, the second metal plate 62 may be made of a material having the same heat transfer coefficient as the first metal plate 61, or it may be made of a material having a lower heat transfer coefficient than the first metal plate 61.

[0069] ○ In this embodiment, for example, the tip of each extended portion 62b may be thermally connected to the mounting surface 54 of the housing 14. ○ In this embodiment, for example, the tip of each extended portion 62b may be bent along the mounting surface 54. The bent portion may be thermally connected to the mounting surface 54.

[0070] ○ In this embodiment, the first metal plate 61 does not have to have a pair of upright portions 61b. The pair of extending portions 62b may be electrically connected to the first metal plate 61 by joining each of the extending portions 62b to both ends of the first metal plate body portion 61a.

[0071] ○ In one embodiment, each joint 64 may be located outside each recess 55. ○ In this embodiment, each extended portion 62b and each upright portion 61b may be joined together, for example, by soldering. Therefore, the joint portion 64 may be the portion where each extended portion 62b and each upright portion 61b are soldered to each other.

[0072] ○ In this embodiment, each extended portion 62b and each upright portion 61b may be in direct contact with the inner surface of each recess 55. The point is that each extended portion 62b and each upright portion 61b is inserted into each recess 55 and thermally connected to the inner surface of the recess 55.

[0073] ○ In this embodiment, through holes may be formed in the portion of the first metal plate body 61a that overlaps with each winding 51. Adhesive may be placed inside the through holes, and each winding 51 may be joined to the mounting surface 54 via the adhesive. This allows the heat generated from each winding 51 to be dissipated to the mounting surface 54 via the adhesive.

[0074] ○ In the embodiment, the shape of the core 50 is not particularly limited as long as it is annular. ○ In this embodiment, the width of the first metal plate body portion 61a may be different from the width of each upright portion 61b.

[0075] ○ In this embodiment, the width of the second metal plate body portion 62a may be different from the width of each extended portion 62b. ○ In this embodiment, the housing 14 is configured such that the part housing the inverter device 30 and the part housing the compression unit 18 and the motor 19 are integrated into one unit, but a separate housing may be added so that each part is separate.

[0076] ○ In this embodiment, the compression section 18 is not limited to a scroll type, but may also be a piston type, vane type, or the like. ○ In this embodiment, the electric compressor 11 was used in the vehicle air conditioning system 10, but it is not limited to this. For example, the electric compressor 11 may be installed in a fuel cell vehicle and compress the air supplied to the fuel cell as a fluid using the compression unit 18. [Explanation of Symbols]

[0077] 11...Electric compressor, 14...Housing, 18...Compression section, 19...Motor, 30...Inverter device, 34...Circuit board, 35...Inverter circuit, 36...Noise reduction section, 38...Common mode choke coil, 39...Smoothing capacitor, 40...Low-pass filter, 50...Core, 51...Winding, 55...Recess, 60...Conductor, 61...First metal plate, 61b...Upright section, 62...Second metal plate, 62a...Second metal plate main body as the main body section, 62b...Extending section, 64...Joint section.

Claims

1. A compression section that compresses the fluid, A motor that drives the compression section, It comprises an inverter device housed in a metal housing that drives the motor, The inverter device is, An inverter circuit that converts DC power to AC power, A noise reduction unit is provided on the input side of the inverter circuit and reduces common-mode noise and normal-mode noise contained in the DC power input to the inverter circuit. The system comprises a circuit board on which the inverter circuit and the noise reduction unit are mounted, The noise reduction unit is Common mode choke coil and The system comprises a smoothing capacitor that, together with the common mode choke coil, constitutes a low-pass filter, The common mode choke coil is, A ring-shaped core, A pair of windings wound around the core, The system comprises an annular conductor covering both of the pair of windings, The conductor is divided into a first metal plate and a second metal plate that form the annular shape. An electric compressor in which an induced current flows in the circumferential direction of the ring between the first metal plate and the second metal plate in such a way as to resist the change in leakage magnetic flux from the core, The circuit board is positioned relative to the housing with the common mode choke coil in between. The second metal plate is A main body portion is positioned with the pair of windings sandwiched between the first metal plate, It has a pair of extending portions that extend from the main body toward the housing, The housing has a pair of recesses, Of the first metal plate and the second metal plate, at least the second metal plate is thermally connected to the housing by the tip of each of the extended portions being inserted into each of the recesses, The first metal plate is thermally connected to the second metal plate, An electric compressor characterized in that at least one of the electrical resistance and thermal resistance values ​​in the current path of the induced current is smaller for the second metal plate than for the first metal plate.

2. The first metal plate has a pair of upright portions that stand up toward the housing, The electric compressor according to claim 1, characterized in that each of the upright portions is inserted into each of the recesses and is thermally connected to the housing.

3. The conductor comprises a plurality of joining portions that metallically join the tip portion of each extended portion to each upright portion, The electric compressor according to claim 2, characterized in that the joint portion is arranged inside each of the recesses and is thermally connected to the housing.

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