CN112673171A

CN112673171A - Electric compressor

Info

Publication number: CN112673171A
Application number: CN201980061167.XA
Authority: CN
Inventors: 本间郁人; 关根和孝
Original assignee: Sanden Automotive Conponents Corp
Current assignee: Sanden Automotive Conponents Corp; Sanden Automotive Components Corp
Priority date: 2018-09-27
Filing date: 2019-09-12
Publication date: 2021-04-16
Also published as: JP2020051328A; DE112019004875T5; WO2020066638A1

Abstract

[ problem ] to provide an electric compressor capable of improving the reliability of electrical insulation over time. In an electric compressor using a polyalkylene glycol-based lubricating oil as a lubricating oil, a stator coil of an electric motor housed in a casing together with a compression mechanism for compressing a refrigerant is formed by winding an insulated wire (60) having an insulating film (62) formed on a linear conductor (61) around a stator core. The insulating film (62) comprises two or more insulating layers (621-623), and the two or more insulating layers (621-623) are all formed of a polyamide-imide resin.

Description

Electric compressor

Technical Field

The present invention relates to an electric compressor in which a compression mechanism for compressing a refrigerant and an electric motor are accommodated in a casing.

Background

Patent document 1 describes an example of a conventional electric compressor. The electric compressor described in patent document 1 includes a housing having a suction port and a discharge port, an electric motor housed in the housing, and a compression unit housed in the housing. The electric motor includes: a stator coil in which a conductive wire having an electrically insulating layer coated on an electrically conductive wire material is wound; and a rotor that rotates a rotating shaft based on a rotating magnetic field generated from the stator coil. The electric compressor is driven by the rotary shaft, sucks a refrigerant in which a polyalkylglycol as a lubricating oil is dissolved through the suction port, compresses the sucked refrigerant, and discharges the compressed refrigerant from the discharge port.

In patent document 1, when one end side of the stator coil is connected to the drive circuit side, it is not necessary to peel off the electrical insulation layer of the lead wire in the case, and thus electrical insulation of the electric compressor is ensured.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2009-203902.

Disclosure of Invention

Problems to be solved by the invention

However, in the conventional electric compressor, the electric insulating layer of the lead wire is not sufficiently studied. For example, when the lead wires are wound or the electric compressor is operated, the lead wires may rub against each other to cause slight damage to the electric insulating layer. Such a small damage is not a problem in itself, but may become a starting point of a larger damage of the electrical insulating layer. If the damage becomes a starting point and the electric insulation layer is damaged more largely, the electric insulation of the electric compressor cannot be ensured.

Accordingly, an object of the present invention is to provide an electric compressor capable of improving reliability of electrical insulation over time.

Means for solving the problems

According to one aspect of the present invention, a motor-driven compressor is provided. The electric compressor includes: an electric motor that rotates the rotating shaft; a compression mechanism driven by the rotary shaft to compress a refrigerant; and a housing having a suction port and a discharge port, and accommodating the rotary shaft, the electric motor, and the compression mechanism; the refrigerant sucked from the suction port is compressed by the compression mechanism and discharged from the discharge port. In the electric compressor, a polyalkylene glycol-based lubricating oil is used as the lubricating oil. The electric motor includes a stator core, a stator coil in which an insulated wire having an insulating film formed on a surface of a linear conductor is wound around the stator core, and a rotor attached to the rotating shaft; the rotating shaft is configured to be rotated via the rotor by energization of the stator coil. The insulating film includes two or more insulating layers, and the two or more insulating layers are all formed of a polyamide-imide resin.

Effects of the invention

In the electric compressor, the insulating film of the insulated wire includes two or more insulating layers, and all of the two or more insulating layers are formed of a polyamide-imide resin. Therefore, according to the electric compressor, the reduction of the electrical insulation property over time, which is mainly caused by the damage generated in the insulating film, can be suppressed, and the reliability of the electrical insulation over time can be improved.

Drawings

Fig. 1 is a diagram illustrating an electric compressor according to an embodiment of the present invention.

Fig. 2 is a diagram schematically showing an electric motor in the aforementioned electric compressor.

Fig. 3 is a sectional view of an insulated wire constituting a stator coil of the electric motor.

Fig. 4 is a table showing the results of the accelerated aging tests of examples 1, 2 and comparative examples 1, 2.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Fig. 1 is a diagram showing an electric compressor 1 according to an embodiment of the present invention. The electric compressor 1 according to the embodiment is a horizontal inverter-integrated electric compressor in which a compression mechanism and an electric motor are arranged in a horizontal direction in a casing so as to be aligned in a row, and an inverter as a motor drive circuit is integrally provided. The electric compressor 1 according to the embodiment is applied to, for example, an air conditioner for a vehicle, and is configured as a refrigeration cycle apparatus in which a condenser, a decompressor (an expansion valve or the like), and an evaporator are incorporated in a refrigerant circulation path through which a refrigerant circulates.

In the present embodiment, HFC134a (R-134a) is used as the refrigerant. A polyalkylene glycol-based lubricant (hereinafter referred to as "PAG-based lubricant") containing a polyalkylene glycol (PAG) as a main component is used as a refrigerating machine oil (lubricant). The PAG-based lubricating oil and the refrigerant are circulated in the refrigerant circulation passage together (dissolved in the refrigerant).

As shown in fig. 1, the casing 2 of the electric compressor 1 includes a main casing 21, an inverter casing 22, an inverter cover 23, and a discharge casing 24. The main casing 21, the inverter casing 22, the inverter cover 23, and the discharge casing 24 are each formed of a conductive metal material such as aluminum. The main case 21 and/or the inverter case 22 are connected to a metal part of the vehicle body via an unillustrated ground line.

The main housing 21 is formed in a substantially cylindrical shape. On one end side (left side in fig. 1) of the peripheral wall of the main casing 21, a suction port 21a is formed that sucks in refrigerant from the evaporator side. In the present embodiment, the suction port 21a is provided in the upper portion of the main casing 21 and is open on the upper side. The compression mechanism 3, the rotary shaft 4, and the electric motor 5 are accommodated in the main housing 21.

The opening of the one end side of the main case 21 is closed by the inverter case 22. The inverter case 22 is fastened to the main case 21 by bolts (not shown). The inverter case 22 is formed in a bottomed cylindrical shape, and a bottom wall portion thereof constitutes a partition wall 7 that partitions the inside of the main case 21 and the inside of the inverter case 22.

In the inverter case 22, an inverter 8 as a motor drive circuit is housed. The opening of the inverter case 22 on the opposite side of the bottom wall portion is closed by an inverter cover 23. The inverter cover 23 is fastened to the inverter case 22 by bolts (not shown).

The opening on the other end side of the main casing 21 is closed by the discharge casing 24. The discharge casing 24 is fastened to the main casing 21 by bolts (not shown). The discharge casing 24 is formed with a discharge port 24a for discharging the refrigerant on the condenser side and a discharge passage 24b for guiding the refrigerant to the discharge port 24 a. In the present embodiment, the discharge port 24a is provided at the upper portion of the discharge housing 24 and is open at the upper side.

The compression mechanism 3 is disposed on the discharge casing 24 side in the main casing 21. The compression mechanism 3 is driven by rotation of the rotary shaft 4, receives and compresses a refrigerant sucked into the main casing 21 from the suction port 21a, and discharges the compressed refrigerant. The refrigerant discharged from the compression mechanism 3 is guided to the discharge port 24a by the discharge passage 24b, and discharged from the discharge port 24 a. Without particular limitation, a compression mechanism of a scroll type including a fixed scroll and a movable scroll, for example, can be employed as the compression mechanism 3.

The rotary shaft 4 extends in the axial direction of the main housing 21. The rotary shaft 4 is rotatably supported within the main casing 21 by bearings, not shown, in a state in which one end thereof is coupled to the compression mechanism 3 via the coupling portion 9.

In the case where the compression mechanism 3 is the scroll-type compression mechanism, the coupling 9 may be a crank mechanism that converts the rotational motion of the rotary shaft 4 into the orbiting motion of the movable scroll. The scroll compression mechanism as the compression mechanism 3 is configured such that the movable scroll revolves with respect to the fixed scroll by rotation of the rotary shaft 4, thereby taking in and compressing a refrigerant, and discharging the compressed refrigerant.

The electric motor 5 is disposed on the inverter case 22 side in the main case 21. That is, the electric motor 5 is disposed in the main casing 21 at a position closer to the suction port 21a than the compression mechanism 3. The electric motor 5 is configured to rotate the rotary shaft 4. In other words, the electric motor 5 is configured to drive the compression mechanism 3 via the rotary shaft 4. In the present embodiment, the electric motor 5 is a three-phase motor.

Fig. 2 is a diagram schematically showing the electric motor 5. As shown in fig. 1 and 2, the electric motor 5 has a stator core 51, a stator coil 52, and a rotor 53.

The stator core 51 is formed of a magnetic material into a substantially cylindrical shape. The stator core 51 is supported by the inner wall of the main housing 21. The stator core 51 has a plurality of teeth 511 protruding toward the inside (toward the rotary shaft 4). The plurality of teeth 511 are arranged at equal intervals in the circumferential direction. Specifically, the plurality of (here, 12) teeth 511 includes a plurality of (here, 4) U-phase teeth 511U, a plurality of (here, 4) V-phase teeth 511V, and a plurality of (here, 4) W-phase teeth 511W. The plurality of teeth 511 are arranged at equal intervals in the circumferential direction, i.e., U-phase teeth 511U → V-phase teeth 511V → W-phase teeth 511W → U-phase teeth 511U → … → W-phase teeth 511W.

The stator coil 52 is constituted by a U-phase coil 52U, a V-phase coil 52V, and a W-phase coil 52W. The stator coil 52 (i.e., each of the U-phase coil 52U, the V-phase coil 52V, and the W-phase coil 52W) is configured by winding the insulated wire 60 around the stator core 51 in concentrated windings. Specifically, the U-phase coil 52U is configured by winding the insulated wire 60 around each of the U-phase teeth 511U among the plurality of teeth 511 of the stator core 51, the V-phase coil 52V is configured by winding the insulated wire 60 around each of the V-phase teeth 511V among the plurality of teeth 511 of the stator core 51, and the W-phase coil 52W is configured by winding the insulated wire 60 around each of the W-phase teeth 511W among the plurality of teeth 511 of the stator core 51. Further, a specific structure of the insulated wire 60 will be described later.

The rotor 53 is disposed radially inward of (the plurality of teeth 511 of) the stator core 51. The rotor 53 incorporates permanent magnets, not shown. The rotor 53 is formed in a cylindrical shape, and is fixed to the rotating shaft 4 in a state where the rotating shaft 4 is inserted through a hollow portion thereof. That is, the rotor 53 is attached to the rotary shaft 4 and rotates integrally with the rotary shaft 4.

The inverter 8 includes various electronic components such as a smoothing capacitor and a power module including a plurality of power switching elements, and a circuit board on which the various electronic components are mounted. The inverter 8 is connected to an external power supply (an in-vehicle battery or the like) via a first power supply line (not shown), and is connected to (a stator coil 52 of) the electric motor 5 via a second power supply line (not shown) penetrating the partition wall 7 in an airtight and liquid-tight manner.

When a power supply voltage is supplied from the external power supply, the inverter 8 outputs a three-phase ac current to the stator coil 52 of the electric motor 5. That is, the stator coil 52 is energized. When the stator coil 52 is energized, a rotating magnetic field is generated, and the rotor 53 rotates in synchronization with the generated rotating magnetic field. Thereby, the rotary shaft 4 rotates, and the compression mechanism 3 is driven. The refrigerant is drawn into the main casing 21 from the suction port 21 a.

The refrigerant sucked into the main casing 21 from the suction port 21a first passes through the electric motor 5 and then the compression mechanism 3 as indicated by an arrow F in fig. 1. That is, the refrigerant sucked from the suction port 21a passes through the electric motor 5 and the compression mechanism 3 in this order. Then, the refrigerant sucked from the suction port 21a cools the electric motor 5 when passing through the electric motor 5, is compressed by the compression mechanism 3 when passing through the compression mechanism 3, and is discharged from the discharge port 24 a.

Next, the structure of the insulated wire 60 constituting the stator coil 52 will be specifically described. Fig. 3 is a sectional view of the insulated wire 60. As shown in fig. 3, the insulated wire 60 is a wire in which an insulating coating 62 is formed on a linear conductor (core wire) 61. That is, the insulated wire 60 has a conductor (core wire) 61 and an insulating coating 62 covering the surface of the conductor (core wire) 61. The conductor (core wire) 61 is, without particular limitation, a copper wire having a diameter of 0.5 to 2 mm, preferably 0.8 to 1.5 mm, and the insulating coating 62 has a thickness of 0.02 to 0.05 mm, preferably 0.03 to 0.04 mm.

The insulating film 62 includes two or more electrical insulating layers (hereinafter simply referred to as "insulating layers") all of which are formed of a polyamide-imide resin. Specifically, in the present embodiment, the insulating film 62 is composed of the outer insulating layer 621 disposed on the outermost side, the inner insulating layer 622 disposed on the innermost side (i.e., disposed on the surface of the conductor (core wire) 61), and the intermediate insulating layer 623 disposed between the outer insulating layer 621 and the inner insulating layer 622, and the outer insulating layer 621, the inner insulating layer 622, and the intermediate insulating layer 623 are each composed of the polyamide-imide resin. The polyamideimide resin is a resin mainly composed of Polyamideimide (PAI), and may contain an additive such as a function-imparting agent. The thicknesses of the insulating

layers

621, 622, and 623 constituting the insulating film 62 are set to be substantially equal to each other. However, without being limited thereto, for example, "the thickness of the outer insulating layer 621 < the thickness of the intermediate insulating layer 623 ≦ the thickness of the inner insulating layer 622" may be set.

Preferably, in the insulating film 62, the outer insulating layer 621 has higher self-lubricity than the inner insulating layer 622 and the intermediate insulating layer 623. In other words, the static friction coefficient of the outer insulating layer 621 is smaller than the static friction coefficient of the inner insulating layer 622 and the static friction coefficient of the intermediate insulating layer 623.

For example, it is possible that the outer insulating layer 621 is a layer composed of high-lubrication polyamide imide (hereinafter referred to as "high-lubrication PAI"), the intermediate insulating layer 623 is a layer composed of general-purpose polyamide imide (hereinafter referred to as "general-purpose PAI"), and the inner insulating layer 622 is a layer composed of the aforementioned general-purpose PAI or high-adhesion polyamide imide (hereinafter referred to as "high-adhesion PAI"). The high-lubricity PAI is, for example, polyamideimide to which a lubricity improver is added, and the high-adhesion PAI is, for example, polyamideimide to which an adhesion improver is added. The general PAI is a polyamide-imide to which the lubricity improver and the adhesion improver are not added.

In the case where the insulating film 62 is composed of two insulating layers (an outer insulating layer and an inner insulating layer), there is a possibility that the outer insulating layer is a layer composed of the high-lubricity PAI and the inner insulating layer is a layer composed of the general-purpose PAI or the high-adhesion PAI.

The main reason why the insulating coating 62 of the insulated wire 60 constituting the stator coil 52 is configured as described above is as follows.

In the present embodiment, the insulated wire 60 is wound in concentrated windings around (each tooth 511 of) the stator core 51. The concentrated winding is more likely to cause the insulated wires 60 to rub against each other during winding of the insulated wires 60 and during operation of the electric compressor 1 than the distributed winding. That is, in the present embodiment, the insulated wire 60 constituting the stator coil 52 may have a tendency that the insulating film 62 thereof is easily damaged. If the insulating film 62 is damaged, the insulation of the insulated wire 60 is reduced. Therefore, the surface of the insulated wire 60 (i.e., the surface of the insulating coating 62) is preferably as smooth as possible.

In the case where the insulating coating 62 is composed of a single layer, damage caused on the surface of the insulating coating 62 tends to progress toward the inside of the insulating coating 62 (toward the wire (core wire) 61) as compared with the case where the insulating coating 62 is composed of a plurality of layers. As described above, the surface of the insulating coating 62 is preferably smooth, and in addition to this, the insulating coating 62 needs to be tightly adhered to the conductor (core wire) 61. That is, the insulating film 62 requires different characteristics between the outer surface and the inner surface thereof. Thus, the insulating film 62 is preferably not a single layer but composed of multiple layers.

As described above, the electric compressor 1 according to the present embodiment is a horizontal inverter-integrated electric compressor. Therefore, if a liquid mainly composed of liquefied refrigerant and lubricating oil accumulates in the lower portion of main housing 21, stator coil 52 (i.e., insulated electric wire 60) located at the lower portion of stator core 51 is immersed in the accumulated liquid. Here, the PAG-based lubricating oil used as the lubricating oil in the present embodiment has lower electrical insulation properties than other lubricating oils. The liquid thus accumulated usually contains foreign matters (impurities) such as moisture and metal powder. Therefore, if the insulation of the insulated wire 60 located below the stator core 51 is reduced by damage or the like of the insulating film 62, the conductor (core wire) 61 of the insulated wire 60 and the main housing 21 are electrically connected through the PAG-based lubricating oil and moisture in the accumulated liquid, and there is a possibility that a leakage current flows from the conductor (core wire) 61 of the insulated wire 60 to the main housing 21.

As described above, the main case 21 and/or the inverter case 22 bolted to the main case 21 are connected to the metal part of the vehicle body via the ground line, and even if a leakage current (weak leakage current) of a certain degree flows through the main case 21 from the conductor (core wire) 61 of the insulated wire 60, this is not a problem. However, since the damaged portion of the insulating film 62 in the insulated wire 60 is immersed in the accumulated liquid and the leakage current continues to flow, the damage of the insulating film 62 becomes a starting point, and the insulating film 62 is more damaged, which may increase the leakage current. In such a state, it cannot be said that the electric insulation of the electric compressor 1 is ensured, and the electric compressor 1 cannot perform its original function, and causes a failure of other electronic equipment located in the vicinity of the electric compressor 1. Thus, the insulating film 62 is preferably formed of a material excellent not only in mechanical properties but also in chemical resistance, hydrolysis resistance, and the like.

For the above reasons, in the present embodiment, in order to suppress the insulating films 62 from being damaged by friction between the insulated wires 60, the insulating films 62 are configured as described above, such that the insulating films 62 of the insulated wires 60 constituting the stator coil 52 are prevented from moving inward even when the insulating films 62 are damaged, and such that the insulating films 62 are prevented from being deteriorated even when the insulated wires 60 are immersed in the accumulated liquid in a state where the insulating films 62 are damaged. That is, the insulating film 62 includes two or more

insulating layers

621 and 623, the two or more

insulating layers

621 and 623 are all formed of a polyamideimide resin excellent in chemical resistance, hydrolysis resistance, and the like, and the outer insulating layer 621 disposed on the outermost side has higher self-lubricity than the inner insulating layer 622 disposed on the innermost side and the intermediate insulating layer 623 disposed between the outer insulating layer 621 and the inner insulating layer 622.

In the electric compressor 1 according to the present embodiment, the insulating film 62 of the insulated wire 60 constituting the stator coil 52 has the above-described configuration, and thus damage to the insulating film 62 is suppressed, and even when the insulating film 62 is damaged and/or is immersed in the accumulated liquid, a decrease in electrical insulation over time of the electric compressor 1 mainly caused by the damage is suppressed, and reliability over time of electrical insulation of the electric compressor 1 is improved.

In the above embodiment, HFC134a was used as the refrigerant. However, the present invention is not limited to this, and refrigerants other than HFC134a may be used.

In the above embodiment, the insulated wire 60 is wound in concentrated windings around the stator core 51. However, not limited thereto, the insulated electric wire 60 may also be wound in distributed windings with respect to the stator core 51. However, since the insulating coating 62 tends to be damaged more easily in one of the concentrated windings than in the distributed winding, the effect of the present invention is more remarkable in one of the cases where the insulated wire 60 is wound in the concentrated winding with respect to the stator core 51 than in the case where the insulated wire is wound in the distributed winding.

Further, in the above-described embodiment, the electric motor 5 is a radial gap motor having a radial gap between the stator core 51 and the rotor 53, and is an inner rotor type motor in which the rotor 53 is disposed radially inside the substantially cylindrical stator core 51. However, the electric motor 5 is not limited to this, and may be an outer rotor type motor in which a rotor is disposed radially outside a stator core, or an axial gap type motor in which an axial gap is provided between the stator core and a coil.

Further, in the above-described embodiment, the conductor (core wire) 61 of the insulated wire 60 has a circular cross-sectional shape (see fig. 3). However, it is not limited thereto. The cross-sectional shape of the conductor (core wire) 61 of the insulated electric wire 60 may be various shapes such as an ellipse (oblong) shape, a rectangle (oblong) shape, and the like.

Examples

The present invention will be described in detail below with reference to examples. However, the following examples do not limit the present invention. In the electric compressor 1 according to each of the following examples and comparative examples, the stator coil 52 is common to the configurations other than the insulated wire 60.

[ example 1]

In example 1, an insulated wire in which a conductor (core wire) 61 is a copper wire having a diameter of 1 mm and an insulating film 62 is a first insulating film having a three-layer structure was used as the insulated wire 60 constituting the stator coil 52. The first insulating film of the aforementioned three-layer structure is formed with an outer insulating layer composed of high-lubrication PAI, an intermediate insulating layer composed of general-purpose PAI, and an inner insulating layer composed of general-purpose PAI. The thickness of the first insulating film is 0.033 to 0.035mm, and the thickness of each insulating layer is 0.010 to 0.015 mm.

[ example 2]

In example 2, an insulated wire in which a conductor (core wire) 61 is a copper wire having a diameter of 1 mm and an insulating film 62 is a second insulating film having a two-layer structure was used as the insulated wire 60 constituting the stator coil 52. The second insulating film having the two-layer structure is formed of an outer insulating layer composed of a high-lubrication PAI and an inner insulating layer composed of a high-adhesion PAI. The thickness of the second insulating film is 0.033 to 0.035mm, and the thickness of each insulating layer is 0.015 to 0.020 mm.

Comparative example 1

In comparative example 1, an insulated wire in which a conductor (core wire) 61 is a copper wire having a diameter of 1 mm and an insulating film 62 is a third insulating film having a three-layer structure was used as the insulated wire 60 constituting the stator coil 52. The third insulating film of the aforementioned three-layer structure is formed with an outer insulating layer composed of high-lubrication PAI, an intermediate insulating layer composed of general-purpose PAI, and an inner insulating layer composed of polyester imide (PEI). The thickness of the first insulating film is 0.033 to 0.035mm, and the thickness of each insulating layer is 0.010 to 0.015 mm.

Comparative example 2

In comparative example 2, an insulated wire in which a conductor (core wire) 61 is a copper wire having a diameter of 1 mm and an insulating film 62 is a fourth insulating film having a two-layer structure was used as the insulated wire 60 constituting the stator coil 52. The fourth insulating film of the aforementioned two-layer structure is formed with an outer insulating layer composed of high-lubrication PAI and an inner insulating layer composed of polyester imide (PEI). The thickness of the fourth insulating film is 0.033 to 0.035mm, and the thickness of each insulating layer is 0.010 to 0.015 mm.

[ accelerated aging test ]

The accelerated aging test was performed under the following conditions.

(1) In each of examples 1 and 2 and comparative examples 1 and 2, the conductor (core wire) 61 was damaged to a slight degree by the insulating film 62 of the insulated wire 60 located below the stator core 51.

(2) In each of examples 1 and 2 and comparative examples 1 and 2, a liquid in which a liquid refrigerant (HFC134a) and the PAG-based lubricating oil were mixed and a predetermined amount of the foreign matter (impurity) was mixed was stored in the main case 21, and the lower portion of the stator core 51 (the insulated wire 60 located therein) was immersed in the liquid.

(3) A direct-current voltage (500V) is applied between stator coil 52 and main case 21, a leakage current flowing from conductor (core wire) 61 of insulated wire 60 to main case 21 is generated, and insulation resistance between conductor (core wire) 61 of insulated wire 60 and main case 21 is measured by an insulation resistance meter.

[ results of accelerated aging test ]

The results of the accelerated aging test are shown in fig. 4. In contrast to examples 1 and 2 in which the insulation resistance hardly changed even after the lapse of 100 hours from the voltage application time, in comparative examples 1 and 2, it was confirmed that the insulation resistance was greatly reduced from the lapse of approximately 60 hours from the voltage application time. In order to confirm the cause, when observing the insulated wires 60 of examples 1 and 2 and comparative examples 1 and 2, in comparative examples 1 and 2, the inner insulating layer made of polyesterimide was deteriorated and expanded at the damaged portion of the insulating film 62 and the vicinity thereof, and the insulating film 62 was damaged and peeled off. On the other hand, in both of examples 1 and 2, the insulating layer hardly changed in quality, and the insulating film 62 was not damaged or peeled off.

Therefore, the insulating film including the plurality of insulating layers each made of the polyamideimide resin is suitable as the insulating film 62 covering the conductor (core wire) 61 in the insulated electric wire 60 constituting the stator coil 52, and further as the insulating film 62 which is at risk of being damaged and is at risk of being immersed in a liquid including the liquid refrigerant, the PAG-based lubricating oil, and the foreign matter (moisture, metal powder, etc.) together with the conductor (core wire) 61, whereby the reliability of the electrical insulation of the electric compressor 1 over time is improved.

Description of the symbols

1 electric compressor

2 casing

3 compression mechanism

4 rotating shaft

5 electric motor

8 inverter

21 main casing

21a suction port

22 inverter housing

23 inverter cover

24 discharge casing

24a discharge port

24b discharge passage

51 stator core

52 stator coil

52u U phase coil

52v V phase coil

52w W phase coil

60 insulated wire

61 conductor

62 insulating film

621 outer insulating layer

622 inner side insulation layer

623 intermediate insulating layers.

Claims

1. An electric compressor, comprising:

an electric motor including a stator core, a stator coil in which an insulated wire having a linear conductor formed with an insulating film is wound around the stator core, and a rotor attached to a rotating shaft, the rotating shaft being rotated via the rotor by energization of the stator coil;

a compression mechanism driven by the rotary shaft to compress a refrigerant;

a housing that has a suction port and a discharge port, and that houses the rotary shaft, the electric motor, and the compression mechanism;

a compressor mechanism configured to compress the refrigerant sucked from the suction port and discharge the compressed refrigerant from the discharge port, the compressor mechanism being configured to use a polyalkylene glycol-based lubricating oil as the lubricating oil;

wherein the insulating film comprises two or more insulating layers, and the two or more insulating layers are all formed of a polyamide imide resin.

2. The electric compressor according to claim 1, wherein the electric motor is an inner rotor type motor in which the rotor is disposed radially inside the substantially cylindrical stator core.

3. The electric compressor according to claim 1 or 2, wherein the electric motor and the compression mechanism are arranged in a row in a horizontal direction in the housing, and the refrigerant sucked in from the suction port is configured to pass through the electric motor and the compression mechanism in this order and be discharged from the discharge port.

4. The electric compressor according to any one of claims 1 to 3, wherein, of the two or more insulating layers, an outer insulating layer disposed outermost has higher self-lubricity than an inner insulating layer disposed innermost.

5. The electric compressor according to any one of claims 1 to 4, wherein the insulated electric wire is wound in concentrated windings at the stator core.

6. The electric compressor according to any one of claims 1 to 5, wherein the insulating film is composed of three insulating layers, all of which are formed of the polyamideimide-based resin.