Motor compressor

Abstract

To provide a motor compressor capable of easily securing dumping resistance when a large current is input to a common-mode choke coil.SOLUTION: A motor compressor comprises a noise reduction unit 50 that reduces both common-mode noise and normal-mode noise. The noise reduction unit 50 includes: a common-mode choke coil 51 for reducing common-mode noise; and a magnetic damping unit 55 for reducing normal-mode noise. The common-mode choke coil 51 includes: an annular core 60; a first winding 61 wound around the core 60; and a second winding 62 wound around the core 60 and arranged aside the first winding 61 with a gap therebetween. The magnetic damping part 55 is formed of a plate-shaped magnetic material. Eddy currents are generated in the magnetic damping unit 55 due to a leakage magnetic flux leaking from the core 60. The noise reduction unit 50 includes a plurality of magnetic damping units 55. The plurality of magnetic damping units 55 are stacked with insulation layers 73 therebetween.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Patent Document 1 describes an in-vehicle electric compressor mounted on a vehicle such as an electric vehicle. The in-vehicle electric compressor includes a compression unit that compresses a fluid, a motor that drives the compression unit, and an inverter device that drives the motor. The inverter device has an inverter circuit unit and a noise reduction unit. The inverter circuit unit converts DC power into AC power. The noise reduction unit is provided on the input side of the inverter circuit unit. The noise reduction unit reduces common mode noise and normal mode noise.

[0003] The noise reduction unit has a common mode choke coil, a smoothing capacitor, and a damping unit. The common mode choke coil has an annular core, a first winding wound around the core, and a second winding wound around the core and arranged in parallel with the first winding with a gap therebetween. The common mode choke coil reduces common mode noise. The smoothing capacitor constitutes a low-pass filter circuit together with the common mode choke coil. The damping unit is made of a magnetic material. The damping unit is arranged around the common mode choke coil.

[0004] When a normal mode current flows through the first winding and the second winding, magnetic flux leaks from the core. When the leakage magnetic flux leaking from the core flows through the damping unit, eddy currents are generated in the damping unit. The eddy currents generated in the damping unit are converted into thermal energy. Thereby, a damping effect is obtained. The damping unit reduces normal mode noise.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] With the increase in the power supply voltage such as the popularization of electric vehicles in recent years, the current input to the common mode choke coil (hereinafter referred to as "input current") has been increasing. For this reason, it is required to ensure a damping resistor when a large current is input to the common mode choke coil.

Means for Solving the Problems

[0007] The electric compressor for solving the above problems includes a compression part for compressing a fluid, a motor for driving the compression part, and an inverter device for driving the motor. The inverter device includes an inverter circuit part for converting DC power into AC power, and a noise reduction part provided on the input side of the inverter circuit part for reducing common mode noise and normal mode noise. The noise reduction part has an annular core, a first winding wound around the core, and a second winding wound around the core and arranged in parallel with a space from the first winding. It includes a common mode choke coil for reducing common mode noise, a smoothing capacitor for constituting a low-pass filter circuit together with the common mode choke coil, and a magnetic damping part made of a plate-shaped magnetic body that generates eddy currents by leakage magnetic flux leaking from the core and reduces normal mode noise. The noise reduction part has a plurality of the magnetic damping parts, and the gist is that the plurality of magnetic damping parts are laminated via an insulating layer.

[0008] According to the above configuration, since a plurality of magnetic damping parts are laminated via an insulating layer, magnetic saturation is less likely to occur. Therefore, even if the input current to the common mode choke coil increases, the damping resistor is less likely to decrease. Thus, it is easy to ensure the damping resistor when a large current is input to the common mode choke coil.

[0009] In the above-described electric compressor, each of the plurality of magnetic damping portions may extend in the circumferential direction of the core so as to surround the outer periphery of the core. According to the above configuration, each magnetic damping portion extends in the circumferential direction of the core so as to surround the outer periphery of the core. In this case, a more excellent damping effect can be obtained.

[0010] In the above-described electric compressor, the noise reduction portion is made of a plate-shaped non-magnetic body, is disposed so as to surround the first winding and the second winding, and has a non-magnetic body damping portion in which an induced current flows so as to generate a magnetic flux that resists a change in the leakage magnetic flux, and reduces the normal mode noise. Each of the plurality of magnetic damping portions is disposed on the side opposite to the first winding and the second winding with the non-magnetic body damping portion interposed therebetween, and extends in the circumferential direction of the core so as to surround the outer periphery of the core.

[0011] According to the above configuration, the noise reduction portion has a non-magnetic body damping portion made of a non-magnetic body. The non-magnetic body damping portion surrounds the first winding and the second winding. Therefore, an induced current flows through the non-magnetic body damping portion so as to generate a magnetic flux that resists a change in the leakage magnetic flux leaking from the core. Then, the induced current flowing through the non-magnetic body damping portion is converted into thermal energy. Also by this, a damping effect can be obtained.

[0012] Further, the noise reduction portion has a plurality of magnetic damping portions. As a result, the induced current flowing through the non-magnetic body damping portion increases by the amount of increase in the leakage magnetic flux as compared with the case where the noise reduction portion has one magnetic damping portion. Therefore, the damping resistance when a small current is input to the common mode choke coil can be increased.

[0013] For example, when the magnetic damping portion is disposed between the first winding and the second winding and the non-magnetic damping portion, the leakage magnetic flux leaking from the core branches into a loop passing through the magnetic damping portion inside the non-magnetic damping portion and a loop passing outside the non-magnetic damping portion. Then, due to the magnetic flux passing through the magnetic damping portion, the magnetic flux linked to the non-magnetic damping portion decreases, so the induced current flowing through the non-magnetic damping portion also decreases. As a result, the damping effect by the non-magnetic damping portion deteriorates.

[0014] On the other hand, according to the above configuration, the plurality of magnetic damping portions are each disposed on the opposite side of the first winding and the second winding with the non-magnetic damping portion interposed therebetween. In this case, since it is avoided that the magnetic flux linked to the non-magnetic damping portion decreases due to the magnetic flux passing through the magnetic damping portion, the induced current flowing through the non-magnetic damping portion does not decrease. Therefore, it is possible to avoid a decrease in the damping effect by the non-magnetic damping portion.

[0015] Furthermore, each magnetic damping portion extends in the circumferential direction of the core so as to surround the outer periphery of the core. In this case, a more excellent damping effect can be obtained. In the above electric compressor, when the direction in which the first winding and the second winding are arranged is defined as the first direction, and the direction orthogonal to both the axial direction of the core and the first direction is defined as the second direction, each of the plurality of magnetic damping portions includes a pair of side portions arranged so as to sandwich the space between the first winding and the second winding in the second direction, and at least one of the plurality of magnetic damping portions may have a void portion that increases the magnetic resistance in the extending direction on at least one of the pair of side portions.

[0016] According to the above configuration, at least one of the plurality of magnetic damping portions has a void portion that increases the magnetic resistance in the extending direction. The leakage magnetic flux leaking from the core is more likely to flow through a path where no void portion is provided than through a path where a void portion is provided in the magnetic damping portion. Further, according to the above configuration, the void portion is provided in at least one of a pair of side portions arranged so as to sandwich the space between the first winding and the second winding in the second direction. Therefore, the magnetic flux passing through the portion of the core around which the first winding is wound and the magnetic flux passing through the portion of the core around which the second winding is wound can each draw a loop passing through the magnetic damping portion without being obstructed by the void portion.

[0017] In the above electric compressor, the insulating layer may be a resin layer provided on the surface of the magnetic damping portion. According to the above configuration, the insulating layer is a resin layer provided on the surface of the magnetic damping portion. Therefore, insulation between the magnetic damping portions can be easily ensured as compared with the case where the insulating layer is a gap provided between the magnetic damping portions.

Advantages of the Invention

[0018] According to the present invention, it is easy to ensure the damping resistance when a large current is input to the common mode choke coil.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment in which the electric compressor is embodied will be described with reference to FIGS. 1 to 7. The electric compressor is mounted on a vehicle such as an electric vehicle. The electric compressor of the present embodiment is used in a vehicle air conditioner.

[0021] As shown in FIG. 1, the vehicle air conditioner 100 includes an electric compressor 10 and an external refrigerant circuit 101. The external refrigerant circuit 101 supplies refrigerant as a fluid to the electric compressor 10. The external refrigerant circuit 101 has, for example, a heat exchanger and an expansion valve (not shown). In the vehicle air conditioner 100, the refrigerant is compressed by the electric compressor 10, and heat exchange and expansion of the refrigerant are performed by the external refrigerant circuit 101, thereby performing heating and cooling in the vehicle interior.

[0022] The vehicle air conditioner 100 includes an air conditioning ECU 102. The air conditioning ECU 102 controls the entire vehicle air conditioner 100. The air conditioning ECU 102 is configured to be able to grasp the vehicle interior temperature, the set temperature of the car air conditioner, etc. Then, based on parameters such as the vehicle interior temperature and the set temperature of the car air conditioner, the air conditioning ECU 102 transmits various commands such as ON / OFF commands to the electric compressor 10.

[0023] <Electric compressor> The electric compressor 10 includes a housing 11, a rotating shaft 12, a compression part 13 that compresses refrigerant, a motor 14 that drives the compression part 13, and an inverter device 15 that drives the motor 14.

[0024] The housing 11 houses the rotating shaft 12, the compression part 13, the motor 14, and the inverter device 15. The housing 11 is made of metal. The housing 11 of the present embodiment is made of aluminum. The housing 11 is grounded to the vehicle body. The housing 11 has a suction housing 21, a discharge housing 22, and an inverter housing 23.

[0025] The suction housing 21 has a plate-shaped end wall 21a and a peripheral wall 21b that extends cylindrically from the outer peripheral part of the end wall 21a. The discharge housing 22 is connected to the end of the suction housing 21 on the opening side. The discharge housing 22 closes the opening of the suction housing 21. The suction housing 21 and the discharge housing 22 partition a suction chamber S1. The rotating shaft 12, the compression part 13, and the motor 14 are housed in the suction chamber S1. The motor 14 is disposed between the compression part 13 and the end wall 21a of the suction housing 21 in the suction chamber S1.

[0026] The inverter housing 23 has a plate-shaped end wall 23a and a peripheral wall 23b extending cylindrically from the outer peripheral portion of the end wall 23a. The inverter housing 23 is connected to the end wall 21a of the suction housing 21 by bolts B. The end wall 21a of the suction housing 21 and the inverter housing 23 define an inverter accommodation chamber S2. The inverter device 15 is accommodated in the inverter accommodation chamber S2.

[0027] A connector 16 is attached to the end wall 23a of the inverter housing 23. The connector 16 is electrically connected to a power storage device 103 mounted on the vehicle. The power storage device 103 is a power source that supplies power to equipment mounted on the vehicle. The power storage device 103 is a DC power source. The power storage device 103 is, for example, a secondary battery or a capacitor.

[0028] The housing 11 has a suction port 11a. The suction port 11a is formed in the peripheral wall 21b of the suction housing 21. The suction port 11a is formed at a portion of the peripheral wall 21b of the suction housing 21 closer to the end wall 21a than the discharge housing 22. The housing 11 also has a discharge port 11b. The discharge port 11b is formed in the discharge housing 22. The suction port 11a is connected to one end of the external refrigerant circuit 101, and the discharge port 11b is connected to the other end of the external refrigerant circuit 101.

[0029] The rotating shaft 12 is supported in a rotatable state with respect to the housing 11. The axial direction of the rotating shaft 12 coincides with the axial direction of the peripheral wall 21b of the suction housing 21. The compression section 13 is connected to the rotating shaft 12. When the rotating shaft 12 rotates, the compression section 13 compresses the refrigerant. The compression section 13 is, for example, of a scroll type composed of a fixed scroll (not shown) fixed to the suction housing 21 and a orbiting scroll (not shown) disposed opposite to the fixed scroll.

[0030] The motor 14 has a rotor 31 and a stator 32. The rotor 31 has a cylindrical rotor core 33 and a permanent magnet (not shown) provided on the rotor core 33. The rotating shaft 12 is inserted through the rotor core 33. The rotating shaft 12 is fixed to the rotor core 33. The rotating shaft 12 can rotate integrally with the rotor 31.

[0031] The stator 32 faces the rotor 31 and the rotating shaft 12 in the radial direction. The stator 32 has a cylindrical stator core 34, a u-phase coil 35u, a v-phase coil 35v, and a w-phase coil 35w. The stator core 34 is fixed to the inner peripheral surface of the peripheral wall 21b of the suction housing 21. The u-phase coil 35u, the v-phase coil 35v, and the w-phase coil 35w are respectively wound around the stator core 34.

[0032] As shown in FIG. 2, the u-phase coil 35u, the v-phase coil 35v, and the w-phase coil 35w are, for example, Y-connected. The connection mode of the u-phase coil 35u, the v-phase coil 35v, and the w-phase coil 35w is not limited to Y-connection and is arbitrary. The connection mode of the u-phase coil 35u, the v-phase coil 35v, and the w-phase coil 35w may be, for example, delta connection.

[0033] When the u-phase coil 35u, the v-phase coil 35v, and the w-phase coil 35w are energized in a predetermined pattern, the rotor 31 rotates. When the rotor 31 rotates, the rotating shaft 12 rotates. Thereby, the compression part 13 is driven. Therefore, the motor 14 drives the compression part 13. The compression part 13 compresses the refrigerant sucked into the suction chamber S1 from the external refrigerant circuit 101 through the suction port 11a. The refrigerant compressed by the compression part 13 is discharged to the external refrigerant circuit 101 through the discharge port 11b.

[0034] <Inverter device> As shown in FIGS. 1 and 2, the inverter device 15 has a circuit board 41, a holder 42, an inverter circuit part 43, a control part 44, and a noise reduction part 50.

[0035] As shown in FIG. 1, the circuit board 41 is disposed between the end wall 21a of the suction housing 21 and the end wall 23a of the inverter housing 23 in the axial direction of the rotating shaft 12. The thickness direction of the circuit board 41 coincides with the axial direction of the rotating shaft 12.

[0036] The holder 42 is made of resin. The holder 42 is disposed between the circuit board 41 and the end wall 21a of the suction housing 21. The holder 42 has a plate-shaped main body portion 45. The plate thickness direction of the main body portion 45 coincides with the axial direction of the rotating shaft 12. The main body portion 45 has a first surface 45a and a second surface 45b. The first surface 45a and the second surface 45b are each a surface orthogonal to the plate thickness direction of the main body portion 45. The first surface 45a of the main body portion 45 is located on the side of the end wall 21a of the suction housing 21. The second surface 45b of the main body portion 45 is located on the side of the circuit board 41.

[0037] As shown in FIG. 3, the holder 42 has a cylindrical portion 46 erected from the first surface 45a of the main body portion 45. The first surface 45a of the main body portion 45 and the inner peripheral surface 46a of the cylindrical portion 46 define an accommodation space 47.

[0038] The cylindrical portion 46 of the present embodiment is an octagonal cylindrical shape. The cylindrical portion 46 has a pair of first wall portions 461, a pair of second wall portions 462, and four third wall portions 463. The pair of first wall portions 461 face each other. The pair of second wall portions 462 face in a direction orthogonal to the direction in which the pair of first wall portions 461 face. The third wall portion 463 connects the first wall portion 461 and the second wall portion 462.

[0039] As shown in FIG. 1, in the present embodiment, the inverter circuit portion 43 is disposed between the main body portion 45 of the holder 42 and the end wall 21a of the suction housing 21 in the axial direction of the rotating shaft 12. The inverter circuit portion 43 is mounted on the circuit board 41. The inverter circuit portion 43 converts DC power into AC power.

[0040] As shown in Fig. 2, the inverter circuit section 43 has two connection lines EL1 and EL2. The inverter circuit section 43 includes u-phase switching elements Qu1 and Qu2 corresponding to the u-phase coil 35u. The inverter circuit section 43 includes v-phase switching elements Qv1 and Qv2 corresponding to the v-phase coil 35v. The inverter circuit section 43 includes w-phase switching elements Qw1 and Qw2 corresponding to the w-phase coil 35w. Each of the switching elements Qu1 to Qw2 is a power switching element such as an IGBT, for example. Note that freewheeling diodes Du1, Du2, Dv1, Dv2, Dw1, and Dw2 are connected to the switching elements Qu1, Qu2, Qv1, Qv2, Qw1, and Qw2, respectively.

[0041] Each of the u-phase switching elements Qu1 and Qu2 is connected in series. Between each of the u-phase switching elements Qu1 and Qu2, it is connected to the u-phase coil 35u. Then, the series connection of each of the u-phase switching elements Qu1 and Qu2 is electrically connected to both connection lines EL1 and EL2.

[0042] Each of the v-phase switching elements Qv1 and Qv2 is connected in series. Between each of the v-phase switching elements Qv1 and Qv2, it is connected to the v-phase coil 35v. Then, the series connection of each of the v-phase switching elements Qv1 and Qv2 is electrically connected to both connection lines EL1 and EL2.

[0043] Each of the w-phase switching elements Qw1 and Qw2 is connected in series. Between each of the w-phase switching elements Qw1 and Qw2, it is connected to the w-phase coil 35w. Then, the series connection of each of the w-phase switching elements Qw1 and Qw2 is electrically connected to both connection lines EL1 and EL2.

[0044] The control unit 44 controls the inverter circuit unit 43. The control unit 44 controls the switching operations of the switching elements Qu1 to Qw2. The control unit 44 can be realized, for example, by one or more dedicated hardware circuits and / or one or more processors (control circuits) operating according to a computer program (software). The processor includes a CPU and memories such as RAM and ROM, and the memories store program codes or instructions configured to cause the processor to execute various processes. The memory, i.e., the computer-readable medium, includes any available medium accessible by a general-purpose or dedicated computer.

[0045] The control unit 44 is electrically connected to the air-conditioning ECU 102 via the connector 16. Based on a command from the air-conditioning ECU 102, the control unit 44 periodically turns on and off the switching elements Qu1 to Qw2. Specifically, the control unit 44 performs pulse-width modulation control (PWM control) on the switching elements Qu1 to Qw2 based on a command from the air-conditioning ECU 102. More specifically, the control unit 44 generates a control signal using a carrier signal (carrier wave signal) and a command voltage value signal (comparison target signal). Then, the control unit 44 converts DC power into AC power by performing ON / OFF control of the switching elements Qu1 to Qw2 using the generated control signal.

[0046] <Noise reduction unit> The noise reduction unit 50 is provided on the input side of the inverter circuit unit 43. The noise reduction unit 50 reduces common-mode noise and normal-mode noise.

[0047] As shown in FIG. 1, in this embodiment, the noise reduction unit 50 is disposed between the main body portion 45 of the holder 42 and the end wall 21a of the suction housing 21 in the axial direction of the rotating shaft 12. The noise reduction unit 50 is mounted on the circuit board 41.

[0048] As shown in FIG. 2, the noise reduction unit 50 has a common mode choke coil 51 and a smoothing capacitor 52. The smoothing capacitor 52, together with the common mode choke coil 51, constitutes a low-pass filter circuit 53. The low-pass filter circuit 53 is provided on the connection lines EL1 and EL2. Circuit-wise, the low-pass filter circuit 53 is provided between the connector 16 and the inverter circuit unit 43. The common mode choke coil 51 is provided on both connection lines EL1 and EL2.

[0049] The smoothing capacitor 52 is provided on the inverter circuit unit 43 side with respect to the common mode choke coil 51. The smoothing capacitor 52 is an X capacitor connected in parallel to the inverter circuit unit 43. The smoothing capacitor 52 is electrically connected to both connection lines EL1 and EL2. Then, the common mode choke coil 51 and the smoothing capacitor 52 constitute an LC resonance circuit. Therefore, the low-pass filter circuit 53 of the present embodiment is an LC resonance circuit including the common mode choke coil 51.

[0050] The noise reduction unit 50 has two Y capacitors 54. The two Y capacitors 54 are connected in series. The connection between the two Y capacitors 54 is grounded to the vehicle body via the housing 11. The two Y capacitors 54 are provided on the inverter circuit unit 43 side with respect to the common mode choke coil 51. The two Y capacitors 54 are connected in parallel to the common mode choke coil 51. The two Y capacitors 54 are connected in parallel to the smoothing capacitor 52. The two Y capacitors 54 are located between the common mode choke coil 51 and the smoothing capacitor 52.

[0051] The common-mode choke coil 51 suppresses the transmission of high-frequency noise generated on the vehicle side to the inverter circuit section 43 of the electric compressor 10. The common-mode choke coil 51 reduces common-mode noise. Also, the common-mode choke coil 51 utilizes the leakage inductance as the normal inductance. Thereby, the common-mode choke coil 51 is used as the L component in the low-pass filter circuit (LC filter) 53 for removing normal-mode noise (differential-mode noise). That is, the common-mode choke coil 51 can handle common-mode noise and normal-mode noise (differential-mode noise). Therefore, in the electric compressor 10 of the present embodiment, instead of using a common-mode choke coil and a normal-mode (differential-mode) choke coil separately, the common-mode choke coil 51 handles both-mode noise.

[0052] <Common-mode choke coil> As shown in FIG. 4, the common-mode choke coil 51 has a core 60, a first winding 61, and a second winding 62.

[0053] The core 60 is annular. The core 60 is made of a ferromagnetic material. The core 60 is, for example, a ferrite core. The core 60 has a first winding portion 601, a second winding portion 602, and a pair of connecting portions 603. The first winding portion 601 and the second winding portion 602 each extend linearly. The first winding portion 601 and the second winding portion 602 extend in parallel. One connecting portion 603 connects one end portion of the first winding portion 601 and one end portion of the second winding portion 602, and the other connecting portion 603 connects the other end portion of the first winding portion 601 and the other end portion of the second winding portion 602. The core 60 has a first end face 60a and a second end face 60b. The first end face 60a is one end face in the axial direction of the core 60, and the second end face 60b is the other end face in the axial direction of the core 60.

[0054] The first winding 61 is wound around the first winding portion 601 of the core 60. In the present embodiment, a part of the first winding 61 is also wound around a pair of connecting portions 603 of the core 60. Both ends of the first winding 61 are drawn out as a pair of first lead portions 63 from the first end face 60a of the core 60.

[0055] The second winding 62 is wound around the second winding portion 602 of the core 60. In the present embodiment, a part of the second winding 62 is also wound around a pair of connecting portions 603 of the core 60. The second winding 62 is arranged side by side with a space from the first winding 61. In the following description, the direction in which the first winding 61 and the second winding 62 are arranged is defined as the first direction, and the direction orthogonal to both the axial direction of the core 60 and the first direction is defined as the second direction. Both ends of the second winding 62 are drawn out as a pair of second lead portions 64 from the first end face 60a of the core 60.

[0056] The first winding 61 and the second winding 62 each have a first portion 65 located on the first end face 60a of the core 60, a second portion 66 located on the second end face 60b of the core 60, and a third portion 67 located on the outer peripheral surface 60c of the core 60.

[0057] As shown in FIGS. 5(a) and 6, the common mode choke coil 51 is housed in the housing space 47 of the holder 42. The axial direction of the core 60 coincides with the axial direction of the cylindrical portion 46. The first end face 60a of the core 60 is located on the side of the first surface 45a of the main body portion 45. The second end face 60b of the core 60 is located on the side of the end wall 21a of the suction housing 21.

[0058] As shown in FIG. 6, each of the first lead portions 63 and each of the second lead portions 64 are inserted through an insertion hole 45h penetrating the main body portion 45. Each of the first lead portions 63 and each of the second lead portions 64 are soldered to, for example, the circuit board 41. Thereby, the first winding 61 and the second winding 62 are each electrically connected to the circuit board 41.

[0059] <Magnetic damping portion> As shown in FIGS. 3 and 5(a), the noise reduction unit 50 has a plurality of magnetic damping units 55 that reduce normal mode noise. The noise reduction unit 50 of the present embodiment has three magnetic damping units 55. In the present embodiment, the three magnetic damping units 55 have the same configuration. When distinguishing the three magnetic damping units 55, they are referred to as the first magnetic damping unit 55a, the second magnetic damping unit 55b, and the third magnetic damping unit 55c. Each magnetic damping unit 55 is made of a plate-shaped conductive magnetic material. Each magnetic damping unit 55 is made of, for example, iron or electromagnetic steel. Each magnetic damping unit 55 is plate-shaped. The thickness of each magnetic damping unit 55 is several hundred μm. However, in the drawings, the thickness of each magnetic damping unit 55 is exaggeratedly illustrated.

[0060] Each magnetic damping unit 55 is disposed outside the cylindrical portion 46. The first magnetic damping unit 55a is provided along the outer peripheral surface 46b of the cylindrical portion 46. The second magnetic damping unit 55b is provided along the outer peripheral surface of the first magnetic damping unit 55a. The third magnetic damping unit 55c is provided along the outer peripheral surface of the second magnetic damping unit 55b. The three magnetic damping units 55 are laminated in a direction perpendicular to the axial direction of the core 60.

[0061] Each magnetic damping unit 55 extends in the circumferential direction of the core 60 so as to surround the outer periphery of the core 60. Each magnetic damping unit 55 has a pair of first portions 551, a pair of second portions 552, and four third portions 553. The pair of first portions 551 are arranged so as to sandwich the common mode choke coil 51 in the first direction. The pair of second portions 552 are arranged so as to sandwich the common mode choke coil 51 in the second direction. The pair of second portions 552 include a pair of side portions 552a arranged so as to sandwich the space between the first winding 61 and the second winding 62 in the second direction. The third portion 553 connects the first portion 551 and the second portion 552.

[0062] As shown in FIG. 5(b), each magnetic damping portion 55 has a first surface 70a and a second surface 70b. The first surface 70a and the second surface 70b are each a surface of the magnetic damping portion 55 orthogonal to the thickness direction of the magnetic damping portion 55. The first surface 70a constitutes the inner peripheral surface of the magnetic damping portion 55. The second surface 70b constitutes the outer peripheral surface of the magnetic damping portion 55. In the present embodiment, a first resin layer 71 as a resin layer is provided on the first surface 70a of each magnetic damping portion 55. A second resin layer 72 as a resin layer is provided on the second surface 70b of each magnetic damping portion 55. Note that in FIGS. 3 and 5(a), the illustration of the first resin layer 71 and the second resin layer 72 is omitted.

[0063] The first magnetic damping portion 55a and the second magnetic damping portion 55b are insulated by the second resin layer 72 of the first magnetic damping portion 55a and the first resin layer 71 of the second magnetic damping portion 55b. That is, the second resin layer 72 of the first magnetic damping portion 55a and the first resin layer 71 of the second magnetic damping portion 55b constitute an insulating layer 73 interposed between the laminated magnetic damping portions 55.

[0064] The second magnetic damping portion 55b and the third magnetic damping portion 55c are insulated by the second resin layer 72 of the second magnetic damping portion 55b and the first resin layer 71 of the third magnetic damping portion 55c. That is, the second resin layer 72 of the second magnetic damping portion 55b and the first resin layer 71 of the third magnetic damping portion 55c constitute an insulating layer 73 interposed between the laminated magnetic damping portions 55. Thus, the three magnetic damping portions 55 are laminated via the insulating layer 73.

[0065] In each magnetic damping portion 55 of the present embodiment, an air gap portion G that increases the magnetic resistance in the extending direction of the magnetic damping portion 55 is provided. In the present embodiment, the air gap portions G are provided in respective ones of the pair of side portions 552a. Specifically, the air gap portion G is provided on a virtual straight line L that extends along the second direction and is located midway between the first winding 61 and the second winding 62 in the first direction. The air gap portion G of the first magnetic damping portion 55a, the air gap portion G of the second magnetic damping portion 55b, and the air gap portion G of the third magnetic damping portion 55c are aligned in the second direction.

[0066] In the present embodiment, the air gap portion G is provided over the entire thickness direction of the magnetic damping portion 55. Further, the air gap portion G is provided over the entire magnetic damping portion 55 in the axial direction of the core 60. For this reason, the magnetic damping portion 55 is discontinuous in the extending direction of the magnetic damping portion 55 due to the air gap portion G. Therefore, in each magnetic damping portion 55, a portion located on one side of the virtual straight line L in the first direction and a portion located on the other side of the virtual straight line L in the first direction are not electrically connected.

[0067] [Operation of the Present Embodiment] The operation of the present embodiment will be described. The noise reduction portion 50 has a magnetic damping portion 55 made of a plate-shaped magnetic material. When leakage magnetic flux leaking from the core 60 flows through the magnetic damping portion 55 when a normal mode current flows through the first winding 61 and the second winding 62, eddy currents are generated in the magnetic damping portion 55. The eddy currents generated in the magnetic damping portion 55 are converted into thermal energy. Thereby, a damping effect is obtained.

[0068] FIG. 7 is a graph showing the relationship between the input current to the common mode choke coil 51 and the damping resistance for Comparative Example 1, Example 1-1, and Example 1-2. The greater the damping resistance, the better the damping effect. In FIG. 7, the graphs of Comparative Example 1, Example 1-1, and Example 1-2 are indicated by a solid line, a broken line, and a one-dot chain line, respectively.

[0069] In Comparative Example 1, Example 1-1, and Example 1-2, the conditions are set to be the same except for the number of magnetic damping portions 55 to be laminated. In Comparative Example 1, the noise reduction portion 50 has one magnetic damping portion 55. That is, in Comparative Example 1, the magnetic damping portions 55 are not laminated. In Example 1-1, the noise reduction portion 50 has two magnetic damping portions 55, and the two magnetic damping portions 55 are laminated via an insulating layer 73. In Example 1-2, the noise reduction portion 50 has three magnetic damping portions 55, and the three magnetic damping portions 55 are laminated via an insulating layer 73. That is, Example 1-2 is an example corresponding to the first embodiment.

[0070] As is apparent from FIG. 7, the damping resistance decreases as the input current to the common mode choke coil 51 increases. This is a common tendency in Comparative Example 1, Example 1-1, and Example 1-2. However, in Example 1-1 and Example 1-2, the damping resistance decreases more gently than in Comparative Example 1. Furthermore, in Example 1-2, the damping resistance decreases more gently than in Example 1-1. That is, the larger the number of magnetic damping portions 55 to be laminated, the more gently the damping resistance decreases. In other words, the larger the number of magnetic damping portions 55 to be laminated, the less likely the damping resistance is to decrease even when the input current to the common mode choke coil 51 increases. This is because the larger the number of magnetic damping portions 55 to be laminated, the less likely magnetic saturation is to occur. Therefore, in the present embodiment in which a plurality of magnetic damping portions 55 are laminated via an insulating layer 73, it is easy to ensure the damping resistance when a large current is input to the common mode choke coil 51.

[0071] As shown in Fig. 7, when a small current is input to the common mode choke coil 51, the damping resistance of Examples 1-1 and 1-2 is smaller than that of Comparative Example 1. This is because when the number of magnetic damping portions 55 to be laminated increases, the leakage inductance increases, resulting in a decrease in the resonance frequency. Generally, the impedance is larger at higher frequencies. Therefore, when a small current is input to the common mode choke coil 51, the damping resistance becomes smaller as the number of magnetic damping portions 55 to be laminated increases.

[0072] On the other hand, when a large current is input to the common mode choke coil 51, the damping resistance of Examples 1-1 and 1-2 is larger than that of Comparative Example 1. For example, assume that the required damping resistance is X shown in Fig. 7. The current value of the input current when the damping resistance is less than X in Examples 1-1 and 1-2 is larger than the current value of the input current when the damping resistance is less than X in Comparative Example 1. That is, in Examples 1-1 and 1-2, even when the input current is a large current, it is easy to ensure the required damping resistance.

[0073] [Effects of the Present Embodiment] The effects of the present embodiment will be described. (1-1) In the present embodiment, since the three magnetic damping portions 55 are laminated via the insulating layer 73, magnetic saturation is less likely to occur. Therefore, even when the input current to the common mode choke coil 51 increases, the damping resistance is less likely to decrease. Thus, it is easy to ensure the damping resistance when a large current is input to the common mode choke coil 51.

[0074] In addition, when increasing the thickness of a single magnetic damping portion 55 instead of increasing the number of stacked magnetic damping portions 55, eddy currents are generated on the surface of the magnetic damping portion 55 due to the skin effect, but eddy currents are less likely to be generated inside the magnetic damping portion 55. For this reason, even if the thickness of a single magnetic damping portion 55 is the same as the total thickness of a plurality of stacked magnetic damping portions 55, the damping effect is inferior to that of the present embodiment. In other words, by stacking a plurality of magnetic damping portions 55 via the insulating layer 73 as in the present embodiment, eddy currents can be effectively generated in each magnetic damping portion 55, so that a more excellent damping effect can be obtained.

[0075] (1-2) Each magnetic damping portion 55 of the present embodiment extends in the circumferential direction of the core 60 so as to surround the outer periphery of the core 60. In this case, a more excellent damping effect can be obtained. (1-3) Each magnetic damping portion 55 of the present embodiment has a gap portion G that increases the magnetic resistance in the extending direction. The leakage magnetic flux leaking from the core 60 is more likely to flow through a path where the gap portion G is not provided than through a path where the gap portion G is provided in the magnetic damping portion 55. Further, in the present embodiment, the gap portion G is provided in a pair of side portions 552a arranged so as to sandwich the space between the first winding 61 and the second winding 62 in the second direction. For this reason, the magnetic fluxes passing through the first winding portion 601 of the core 60 and the second winding portion 602 of the core 60, which are indicated by the dashed-dotted arrows in FIG. 5(a), can each draw a loop passing through the magnetic damping portion 55 without being obstructed by the gap portion G.

[0076] (1-4) The insulating layer 73 of the present embodiment is the first resin layer 71 provided on the first surface 70a of the magnetic damping portion 55 and the second resin layer 72 provided on the second surface 70b. Therefore, insulation between the magnetic damping portions 55 can be easily ensured as compared with the case where the insulating layer 73 is a gap provided between the magnetic damping portions 55.

[0077] (1-5) The inverter device 15 of this embodiment has a resin holder 42 having a plate-shaped main body 45 and a cylindrical portion 46 erected from the main body 45. The common-mode choke coil 51 is accommodated in an accommodation space 47 defined by the main body 45 and the cylindrical portion 46 such that the axial direction of the core 60 extends in the axial direction of the cylindrical portion 46. Thereby, the position of the common-mode choke coil 51 is less likely to shift. Further, the magnetic damping portion 55 of this embodiment is disposed on the outer periphery of the cylindrical portion 46 of the holder 42. Therefore, the cylindrical portion 46 can insulate the magnetic damping portion 55 from the common-mode choke coil 51.

[0078] [Second Embodiment] Hereinafter, a second embodiment in which an electric compressor is embodied will be described with reference to FIGS. 8 to 11. The main difference from the first embodiment is that the electric compressor further includes a non-magnetic damping portion. For this reason, detailed description of the same configuration as that of the first embodiment will be omitted.

[0079] [Non-magnetic Damping Portion] As shown in FIGS. 8 and 9(a), the noise reduction portion 50 has a plate-shaped non-magnetic damping portion 56 that reduces normal-mode noise. The non-magnetic damping portion 56 is made of a plate-shaped conductive non-magnetic material. The non-magnetic damping portion 56 is made of, for example, copper or aluminum.

[0080] The non-magnetic damping portion 56 of the present embodiment is annular. The non-magnetic damping portion 56 includes a first covering portion 56a, a second covering portion 56b, a third covering portion 56c, and a fourth covering portion 56d. The first covering portion 56a, the second covering portion 56b, the third covering portion 56c, and the fourth covering portion 56d are each in the shape of a rectangular flat plate. The first covering portion 56a and the second covering portion 56b are parallel. A through hole 56h is formed in the second covering portion 56b. The through hole 56h penetrates the second covering portion 56b in the plate thickness direction. The third covering portion 56c connects one end portion in the longitudinal direction of the first covering portion 56a and one end portion in the longitudinal direction of the second covering portion 56b. The fourth covering portion 56d connects the other end portion in the longitudinal direction of the first covering portion 56a and the other end portion in the longitudinal direction of the second covering portion 56b. The third covering portion 56c and the fourth covering portion 56d are parallel.

[0081] As shown in FIGS. 9(a) and 10, the non-magnetic damping portion 56 is housed in the accommodation space 47 of the holder 42 together with the common mode choke coil 51. A part of the common mode choke coil 51 is disposed inside the non-magnetic damping portion 56. The axial direction of the non-magnetic damping portion 56 coincides with the second direction. The first winding portion 601 and the second winding portion 602 of the core 60, the portion of the first winding 61 wound around the first winding portion 601, and the portion of the second winding 62 wound around the second winding portion 602 are located inside the non-magnetic damping portion 56. The pair of connecting portions 603 of the core 60, the portion of the first winding 61 wound around the connecting portion 603, and the portion of the second winding 62 wound around the connecting portion 603 are located outside the non-magnetic damping portion 56. The pair of first lead portions 63 and the pair of second lead portions 64 are respectively located on both sides in the axial direction of the non-magnetic damping portion 56.

[0082] The first covering portion 56a and the second covering portion 56b are arranged so as to sandwich the common mode choke coil 51 in the axial direction of the core 60. The first covering portion 56a is located on the side of the first end face 60a of the core 60. The second covering portion 56b is located on the side of the second end face 60b of the core 60. The first covering portion 56a covers the first portion 65 of the first winding 61 and the second winding 62. The second covering portion 56b covers the second portion 66 of the first winding 61 and the second winding 62. The third covering portion 56c and the fourth covering portion 56d are arranged so as to sandwich the common mode choke coil 51 in the first direction. The third covering portion 56c covers the third portion 67 of the first winding 61. The fourth covering portion 56d covers the third portion 67 of the second winding 62. Thus, the non-magnetic damping portion 56 surrounds the first winding 61 and the second winding 62. The non-magnetic damping portion 56 covers the first portion 65, the second portion 66, and the third portion 67 of the first winding 61 and the second winding 62.

[0083] As shown in FIG. 10, the surface of the first covering portion 56a opposite to the surface facing the common mode choke coil 51 faces the first surface 45a of the main body portion 45 of the holder 42. A heat dissipation grease (not shown) is provided between the surface of the second covering portion 56b opposite to the surface facing the common mode choke coil 51 and the outer surface of the end wall 21a of the suction housing 21. The surfaces of the third covering portion 56c and the fourth covering portion 56d opposite to the surfaces facing the common mode choke coil 51 face the inner surfaces of the pair of first wall portions 461 of the cylindrical portion 46.

[0084] As shown in FIGS. 9(a) and 9(b), the three magnetic damping portions 55 are laminated via an insulating layer 73. Note that, as in the first embodiment, the illustration of the insulating layer 73 is omitted in FIG. 9(a).

[0085] The plurality of magnetic damping portions 55 are each disposed on the opposite sides of the first winding 61 and the second winding 62 of the common mode choke coil 51 with the non-magnetic damping portion 56 interposed therebetween. In the present embodiment, one first portion 551 of each magnetic damping portion 55 is disposed on the opposite sides of the first winding 61 and the second winding 62 with the third covering portion 56c of the non-magnetic damping portion 56 interposed therebetween in the first direction. The other first portion 551 of each magnetic damping portion 55 is disposed on the opposite sides of the first winding 61 and the second winding 62 with the fourth covering portion 56d of the non-magnetic damping portion 56 interposed therebetween in the first direction.

[0086] [Operation of the Present Embodiment] The operation of the present embodiment will be described. The noise reduction portion 50 has a non-magnetic damping portion 56 made of a plate-shaped non-magnetic material. The non-magnetic damping portion 56 surrounds the first winding 61 and the second winding 62. For this reason, an induced current flows through the non-magnetic damping portion 56 so that a magnetic flux that resists a change in the leakage magnetic flux leaking from the core 60 is generated. Then, the induced current flowing through the non-magnetic damping portion 56 is converted into thermal energy. Thereby also, a damping effect is obtained.

[0087] FIG. 11 is a graph showing the relationship between the input current to the common mode choke coil 51 and the damping resistance for Comparative Example 2-1, Comparative Example 2-2, Example 2-1, and Example 2-2. In FIG. 11, the graphs of Comparative Example 2-1, Comparative Example 2-2, Example 2-1, and Example 2-2 are indicated by a two-dot chain line, a solid line, a broken line, and a one-dot chain line, respectively.

[0088] In Comparative Example 2-1, Comparative Example 2-2, Example 2-1, and Example 2-2, the conditions are the same except for the number of magnetic damping portions 55 to be laminated. In Comparative Example 2-1, Comparative Example 2-2, Example 2-1, and Example 2-2, the noise reduction portion 50 has a non-magnetic damping portion 56. In Comparative Example 2-1, the noise reduction portion 50 does not have a magnetic damping portion 55. In Comparative Example 2-2, the noise reduction portion 50 has one magnetic damping portion 55. That is, in Comparative Example 2-1 and Comparative Example 2-2, the magnetic damping portions 55 are not laminated. In Example 2-1, the noise reduction portion 50 has two magnetic damping portions 55, and the two magnetic damping portions 55 are laminated via an insulating layer 73. In Example 2-2, the noise reduction portion 50 has three magnetic damping portions 55, and the three magnetic damping portions 55 are laminated via an insulating layer 73. That is, Example 2-2 is an example corresponding to the second embodiment.

[0089] As is apparent from FIG. 11, in Comparative Example 2-2, Example 2-1, and Example 2-2, the damping resistance is larger than that in Comparative Example 2-1. That is, since the noise reduction portion 50 has both the magnetic damping portion 55 and the non-magnetic damping portion 56, the damping effect is increased as compared with the case where only the non-magnetic damping portion 56 is provided.

[0090] In Example 2-1 and Example 2-2, the damping resistance gradually decreases as compared with Comparative Example 2-2. That is, similar to the first embodiment, the larger the number of magnetic damping portions 55, the more gradually the damping resistance decreases. In other words, the larger the number of magnetic damping portions 55, the less likely the damping resistance is to decrease even when the input current to the common mode choke coil 51 increases. Therefore, in the present embodiment in which a plurality of magnetic damping portions 55 are laminated via the insulating layer 73, it is easy to secure the damping resistance when a large current is input to the common mode choke coil 51.

[0091] Also, in Example 2-1 and Example 2-2, regardless of the input current, the damping resistance is larger than that of Comparative Example 2-2. Further, in Example 2-2, regardless of the input current, the damping resistance is larger than that of Example 2-1. That is, unlike the first embodiment, when the noise reduction unit 50 has the non-magnetic damping unit 56, the larger the number of the magnetic damping units 55, the larger the damping resistance. This is because the larger the number of the magnetic damping units 55, the more the leakage magnetic flux increases, and thus the induced current flowing through the non-magnetic damping unit 56 increases. Therefore, in the present embodiment having the non-magnetic damping unit 56, the damping resistance when a small current is input to the common mode choke coil 51 can be increased.

[0092] [Effects of the Present Embodiment] The effects of the present embodiment will be described. In the present embodiment, in addition to the effects (1-1) to (1-5) of the first embodiment, the following effects can be obtained.

[0093] (2-1) The noise reduction unit 50 of the present embodiment has a non-magnetic damping unit 56 made of a non-magnetic material. The non-magnetic damping unit 56 surrounds the first winding 61 and the second winding 62. Therefore, an induced current flows through the non-magnetic damping unit 56 so that a magnetic flux is generated to resist a change in the leakage magnetic flux leaking from the core 60. Then, the induced current flowing through the non-magnetic damping unit 56 is converted into thermal energy. Also by this, a damping effect can be obtained.

[0094] Also, the noise reduction unit 50 has a plurality of magnetic damping units 55. As a result, the induced current flowing through the non-magnetic damping unit 56 increases by the amount of increase in the leakage magnetic flux as compared with the case where the noise reduction unit 50 has one magnetic damping unit 55. Therefore, the damping resistance when a small current is input to the common mode choke coil 51 can be increased.

[0095] (2-2) For example, when the magnetic damping portion 55 is disposed between the windings 61 and 62 and the non-magnetic damping portion 56, the leakage magnetic flux leaking from the core 60 branches into a loop passing through the magnetic damping portion 55 inside the non-magnetic damping portion 56 and a loop passing outside the non-magnetic damping portion 56. Then, due to the magnetic flux passing through the magnetic damping portion 55, the magnetic flux linking with the non-magnetic damping portion 56 decreases, so the induced current flowing through the non-magnetic damping portion 56 also decreases. As a result, the damping effect by the non-magnetic damping portion 56 deteriorates.

[0096] In contrast, in the present embodiment, each of the plurality of magnetic damping portions 55 is disposed on the opposite side of the first winding 61 and the second winding 62 with the non-magnetic damping portion 56 interposed therebetween. In this case, since it is avoided that the magnetic flux linking with the non-magnetic damping portion 56 decreases due to the magnetic flux passing through the magnetic damping portion 55, the induced current flowing through the non-magnetic damping portion 56 does not decrease. Therefore, it is possible to avoid the deterioration of the damping effect by the non-magnetic damping portion 56.

[0097] (2-3) The non-magnetic damping portion 56 is housed in the housing space 47 of the holder 42 together with the common mode choke coil 51. Thereby, the position of the non-magnetic damping portion 56 is less likely to shift. Further, the magnetic damping portion 55 of the present embodiment is disposed on the outer periphery of the cylindrical portion 46 of the holder 42. Therefore, the cylindrical portion 46 can insulate the magnetic damping portion 55 not only from the common mode choke coil 51 but also from the non-magnetic damping portion 56.

[0098] [Modification Example] Note that each of the above embodiments can be modified as follows. Each of the above embodiments and the following modification examples can be implemented in combination with each other within a technically non-conflicting range.

[0099] ○ The inverter device 15 may not have the holder 42. ○ The cylindrical portion 46 of the holder 42 does not have to be an octagonal cylinder as long as it is cylindrical. ○ The number of the magnetic damping portions 55 laminated via the insulating layer 73 is not limited to three. The number of the magnetic damping portions 55 laminated via the insulating layer 73 may be two, or may be four or more.

[0100] ○ If eddy currents are generated in the magnetic damping portion 55 due to leakage magnetic flux leaking from the core 60, the shape of the magnetic damping portion 55 and the arrangement of the magnetic damping portion 55 with respect to the common mode choke coil 51 may be appropriately changed. However, a plurality of magnetic damping portions 55 are assumed to be laminated via the insulating layer 73.

[0101] The magnetic damping portion 55 may be, for example, flat plate-shaped, or may be L-shaped or U-shaped. The magnetic damping portion 55 may be arranged, for example, so as to cover only the third portion 67 of the first winding 61, or may be arranged so as to sandwich the common mode choke coil 51 in the axial direction of the core 60.

[0102] ○ The shape of the magnetic damping portion 55 and the arrangement of the magnetic damping portion 55 with respect to the common mode choke coil 51 do not have to be the same for all the magnetic damping portions 55. The shape of the magnetic damping portion 55 and the arrangement of the magnetic damping portion 55 with respect to the common mode choke coil 51 may be different for each magnetic damping portion 55. However, a plurality of magnetic damping portions 55 are assumed to be laminated via the insulating layer 73. The whole of the magnetic damping portion 55 and a part of another magnetic damping portion 55 may be laminated via the insulating layer 73, or a part of the magnetic damping portion 55 and a part of another magnetic damping portion 55 may be laminated via the insulating layer 73.

[0103] ○ In the above embodiment, the insulating layer 73 is the first resin layer 71 provided on the first surface 70a of the magnetic damping portion 55 and the second resin layer 72 provided on the second surface 70b, but is not limited thereto. Any insulating layer 73 may be used as long as it insulates the magnetic damping portions 55 from each other by intervening therebetween.

[0104] As an example, the insulating layer 73 may be a gap provided between the magnetic damping portions 55. As another example, the insulating layer 73 may be a member having insulation and separate from the magnetic damping portions 55.

[0105] ○ In the above embodiment, the resin layer is provided on both sides of the magnetic damping portion 55, but it may be provided on only one side of the magnetic damping portion 55. For example, a first resin layer 71 may be provided on the first surface 70a of each magnetic damping portion 55, and a second resin layer 72 may not be provided on the second surface 70b. In this case, the insulating layer 73 is constituted only by the first resin layer 71.

[0106] For example, a second resin layer 72 may be provided on the second surface 70b of each magnetic damping portion 55, and a first resin layer 71 may not be provided on the first surface 70a. In this case, the insulating layer 73 is constituted only by the second resin layer 72.

[0107] ○ In the above embodiment, the void portion G is provided in all of the three magnetic damping portions 55, but it is not limited thereto. The void portion G may be provided in at least one of the plurality of magnetic damping portions 55 laminated via the insulating layer 73. The expression "at least one" used in this specification means "one or more" of the desired options. As an example, the expression "at least one" used in this specification means "only one option" or "both of the two options" if the number of options is two. As another example, the expression "at least one" used in this specification means "only one option" or "any combination of two or more options" if the number of options is three or more.

[0108] The void portion G does not have to be provided in all of the plurality of magnetic damping portions 55 laminated via the insulating layer 73. ○ In the above-described embodiment, the void portion G was provided on both of the pair of side portions 552a of the magnetic damping portion 55, but it may be provided on only one of the side portions 552a. If the void portion G is provided on at least one of the pair of side portions 552a, the effects (1-3) of the first embodiment can be obtained. Note that "at least one of the pair of side portions 552a" means "only one of the side portions 552a", "only the other side portion 552a", or "both side portions 552a".

[0109] ○ In the above-described embodiment, the void portion G was provided on the virtual straight line L, but it may be provided at a position shifted in the first direction with respect to the virtual straight line L. ○ In the above-described embodiment, the void portion G was provided on the side portion 552a of the magnetic damping portion 55, but it may be provided on a portion other than the side portion 552a in the first portion 551, the third portion 553, or the second portion 552.

[0110] ○ The position of the void portion G in the magnetic damping portion 55 does not have to be the same for all the magnetic damping portions 55. The position of the void portion G in the magnetic damping portion 55 may be different, for example, for each magnetic damping portion 55.

[0111] ○ In the above-described embodiment, the void portion G was provided over the entire thickness direction of the magnetic damping portion 55, but it is not limited thereto. The void portion G may be provided in a part of the thickness direction of the magnetic damping portion 55.

[0112] ○ In the above-described embodiment, the void portion G was provided over the entire magnetic damping portion 55 in the axial direction of the core 60, but it is not limited thereto. The void portion G may be provided in a part of the magnetic damping portion 55 in the axial direction of the core 60.

[0113] ○ The plurality of magnetic damping portions 55 may be disposed inside the cylindrical portion 46. In this case, insulation between the magnetic damping portion 55 and the common mode choke coil 51 is ensured. Examples of methods for ensuring insulation include a method of ensuring an insulation distance between the magnetic damping portion 55 and the common mode choke coil 51, and a method of performing an insulation treatment on the surface of the magnetic damping portion 55 facing the common mode choke coil 51. When the magnetic damping portion 55 is disposed inside the cylindrical portion 46 in the second embodiment, in addition to the insulation between the magnetic damping portion 55 and the common mode choke coil 51, insulation between the magnetic damping portion 55 and the non-magnetic damping portion 56 is also ensured.

[0114] In this case, the cylindrical portion 46 can ensure insulation between the magnetic damping portion 55 and other electronic components mounted on the circuit board 41 and located outside the cylindrical portion 46. Further, compared with the case where the magnetic damping portion 55 is disposed outside the cylindrical portion 46, the magnetic damping portion 55 can be brought closer to the core 60, so that a more excellent damping effect can be obtained.

[0115] ○ Not all of the magnetic damping portions 55 need to be disposed outside or inside the cylindrical portion 46. For example, among the two magnetic damping portions 55, one magnetic damping portion 55 may be disposed outside the cylindrical portion 46, and the other magnetic damping portion 55 may be disposed inside the cylindrical portion 46. In this case, the cylindrical portion 46 functions as an insulating layer 73 that insulates one magnetic damping portion 55 from the other magnetic damping portion 55.

[0116] ○ If the core 60 is annular, the shape of the core 60 may be appropriately changed. The core 60 may be, for example, circular annular. ○ In the above embodiment, the core 60 is composed of one component, but it may be composed of two or more components.

[0117] ○ If the non-magnetic damping part 56 surrounds the first winding 61 and the second winding 62, the shape of the non-magnetic damping part 56 may be appropriately changed. The non-magnetic damping part 56 may be, for example, annular.

[0118] ○ In the above embodiment, the non-magnetic damping part 56 is composed of one part, but it may be composed of two or more parts. ○ The noise reduction part 50 may have a plurality of common mode choke coils 51. Also, in the second embodiment, the noise reduction part 50 may have the same number of non-magnetic damping parts 56 as the common mode choke coils 51.

[0119] ○ The compression part 13 is not limited to the scroll type, and may be, for example, a piston type, a vane type, or the like. ○ The electric compressor 10 may be mounted on a fuel cell vehicle. In this case, the electric compressor 10 may compress air as a fluid supplied to the fuel cell by the compression part 13.

[0120] [Appendix] The technical idea understood from the above embodiments and modification examples is described below. [Appendix 1] A compressor that compresses a fluid, a motor that drives the compressor, and an inverter device that drives the motor, wherein the inverter device includes an inverter circuit section that converts DC power into AC power, and a noise reduction section that is provided on the input side of the inverter circuit section and reduces common mode noise and normal mode noise. The noise reduction section includes an annular core, a first winding wound around the core, and a second winding wound around the core and arranged in parallel with a gap from the first winding. The noise reduction section further includes a common mode choke coil that reduces common mode noise, a smoothing capacitor that forms a low-pass filter circuit together with the common mode choke coil, and a magnetic damping section that is made of a plate-shaped magnetic body, generates eddy currents by leakage magnetic flux leaking from the core, and reduces normal mode noise. The noise reduction section has a plurality of the magnetic damping sections, and the plurality of magnetic damping sections are laminated via an insulating layer. The electric compressor is characterized by this structure.

[0121] <Appendix 2> The electric compressor according to Appendix 1, wherein each of the plurality of magnetic damping sections extends in the circumferential direction of the core so as to surround the outer periphery of the core.

[0122] <Appendix 3> The noise reduction section includes a non-magnetic body damping section made of a plate-shaped non-magnetic body, which is arranged to surround the first winding and the second winding, and an induced current flows to generate a magnetic flux that resists changes in the leakage magnetic flux, thereby reducing normal mode noise. Each of the plurality of magnetic damping sections is arranged on the opposite side of the first winding and the second winding with the non-magnetic body damping section interposed therebetween, and extends in the circumferential direction of the core so as to surround the outer periphery of the core. The electric compressor according to Appendix 1 is characterized by this structure.

[0123] <Appendix 4> When the direction in which the first winding and the second winding are arranged is defined as the first direction, and the direction orthogonal to both the axial direction of the core and the first direction is defined as the second direction, each of the plurality of magnetic damping portions includes a pair of side portions arranged so as to sandwich the space between the first winding and the second winding in the second direction, and at least one of the plurality of magnetic damping portions has a gap portion that increases magnetic resistance in the extending direction on at least one of the pair of side portions. The electric compressor according to Appendage 2 or Appendage 3.

[0124] <Appendage 5> The insulating layer is a resin layer provided on the surface of the magnetic damping portion. The electric compressor according to any one of Appendages 1 to 4.

Explanation of Signs

[0125] 10… Electric compressor, 13… Compression portion, 14… Motor, 15… Inverter device, 43… Inverter circuit portion, 50… Noise reduction portion, 51… Common mode choke coil, 52… Smoothing capacitor, 53… Low-pass filter circuit, 55… Magnetic damping portion, 56… Non-magnetic damping portion, 60… Core, 61… First winding, 62… Second winding, 71… First resin layer as a resin layer, 72… Second resin layer as a resin layer, 73… Insulating layer, 552a… Side portion, G… Gap portion.

Claims

1. A compression unit that compresses a fluid, a motor that drives the compression unit, an inverter device that drives the motor, and is provided with, the inverter device includes an inverter circuit unit that converts DC power into AC power, a noise reduction unit provided on the input side of the inverter circuit unit to reduce common mode noise and normal mode noise, and has, the noise reduction unit has an annular core, a first winding wound around the core, and a second winding wound around the core and arranged side by side with a space from the first winding, and a common mode choke coil that reduces the common mode noise, a smoothing capacitor that forms a low-pass filter circuit together with the common mode choke coil, a magnetic damping unit made of a plate-shaped magnetic material that generates eddy currents by leakage magnetic flux leaking from the core and reduces the normal mode noise, is an electric compressor having, the noise reduction unit has a plurality of the magnetic damping units, the plurality of magnetic damping units are laminated via an insulating layer, and the electric compressor is characterized in that.

2. The electric compressor according to claim 1, wherein each of the plurality of magnetic damping units extends in the circumferential direction of the core so as to surround the outer periphery of the core.

3. The noise reduction unit is made of a plate-shaped non-magnetic material, is arranged so as to surround the first winding and the second winding, and an induced current flows so as to generate a magnetic flux that resists a change in the leakage magnetic flux, and has a non-magnetic damping unit that reduces the normal mode noise, The electric compressor according to claim 1, wherein each of the plurality of magnetic damping units is arranged on the opposite side of the first winding and the second winding with the non-magnetic damping unit sandwiched therebetween, and extends in the circumferential direction of the core so as to surround the outer periphery of the core.

4. When the direction in which the first winding and the second winding are arranged is defined as the first direction, and the direction orthogonal to both the axial direction of the core and the first direction is defined as the second direction, each of the plurality of magnetic damping units includes a pair of side portions arranged so as to sandwich the space between the first winding and the second winding in the second direction, the electric compressor according to claim 2 or claim 3, wherein at least one of the plurality of magnetic damping units has a gap portion that increases the magnetic resistance in the extending direction in at least one of the pair of side portions.

5. The electric compressor according to claim 1, wherein the insulating layer is a resin layer provided on the surface of the magnetic damping portion.

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