Compressor

Abstract

The present disclosure provides a compressor which uses a working medium that contains an ethylene-based fluoroolefin, and which is capable of suppressing discharge at a conductor portion of a magnetic coil and the occurrence of a disproportionation reaction of the working medium.　A compressor according to the present disclosure uses a working medium that contains an ethylene-based fluoroolefin and performs air conditioning by driving an electric motor and circulating the working medium in a refrigerant circuit. In this compressor, a conductive layer is formed on the outside of an insulation coating of an electric wire that constitutes a magnetic coil of the electric motor.

Description

Compressor

[0001] The present disclosure relates to a compressor.

[0002] Patent Document 1 discloses an enameled wire having an insulating coating composed of at least two insulating layers around a conductor, the outermost insulating layer being composed of a polyamide-imide coating, and having a mixed resin insulating layer composed of a mixed resin coating of polyimide resin and polyamide-imide resin provided on the inner layer side of the outermost insulating layer.

[0003] Japanese Patent Application Laid-Open No. 2005-302597

[0004] The present disclosure provides a compressor that uses a working fluid containing an ethylene-based fluoroolefin, and that can suppress discharge in the conductor portion of the magnet coil and suppress the occurrence of disproportionation reactions in the working fluid.

[0005] The compressor in the present disclosure uses a working medium containing an ethylene-based fluoroolefin and drives an electric motor to circulate the working medium in a refrigerant circuit to perform air conditioning, and a conductive layer is formed on the outside of the insulating coating of an electric wire that constitutes a magnet coil of the electric motor. This specification includes the entire contents of Japanese Patent Application No. 2023-169476, filed on September 29, 2023.

[0006] According to the compressor of the present disclosure, since the conductive layer is formed on the outside of the insulating coating, the conductive layers of the electric wires come into contact with each other, thereby reducing the potential difference in the area near the contact portion and suppressing the occurrence of discharge in the area near the contact portion, thereby suppressing the occurrence of disproportionation reaction of the working fluid.

[0007] FIG. 1 is a schematic diagram showing the overall configuration of a refrigeration cycle device according to a first embodiment; FIG. 2 is a schematic diagram showing a compressor according to the first embodiment; and FIG. 3 is a schematic diagram showing the electric wires of a magnet coil according to the first embodiment.

[0008] (Knowledge, etc., that Forms the Basis of the Present Disclosure) At the time the inventors arrived at the present disclosure, in a compressor driven by a drive motor of an air conditioner, the conductor of the magnet coil of the drive motor is provided with an enamel insulating layer, and the magnet coil is energized and operated with the conductor in contact with refrigerant vapor. However, when using a working fluid containing an ethylene-based fluoroolefin, if the compressor is driven with the insulating coating of the magnet coil deteriorated and a discharge of a certain amount of energy or more occurs in the conductor of the magnet coil, an autolysis reaction of the working fluid may occur, causing a sudden increase in the pressure of the working fluid. In addition, in compressors, a highly efficient permanent magnet embedded motor is typically driven, and the drive motor is driven by an inverter to vary the rotation speed of the compressor. However, the inventors discovered a problem in that inverter drive applies a surge voltage between the conductors of the magnet coil, which may cause partial discharge and accelerate deterioration of the insulating coating. In order to solve this problem, the inventors have come up with the subject matter of the present disclosure. Therefore, the present disclosure provides a compressor that uses a working fluid containing an ethylene-based fluoroolefin, and that can suppress discharge in the conductor portion of the magnet coil and suppress the occurrence of disproportionation reactions in the working fluid.

[0009] Hereinafter, embodiments will be described in detail with reference to the drawings. However, unnecessary detailed description may be omitted. For example, detailed description of already well-known matters or redundant description of substantially the same configuration may be omitted. Note that the accompanying drawings and the following description are provided to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter described in the claims.

[0010] (Embodiment 1) [1-1. Configuration] [1-1-1. Overall Configuration of Refrigeration Cycle Apparatus] FIG. 1 is a schematic diagram showing the overall configuration of a refrigeration cycle apparatus 1 to which a compressor according to the present disclosure is applied. As shown in FIG. 1, the refrigeration cycle apparatus 1 includes an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 and the indoor unit 20 are connected via a refrigerant pipe 11 to form a refrigerant circuit through which a refrigerant circulates. The refrigeration cycle apparatus 1 uses a working fluid containing an ethylene-based fluoroolefin in the refrigeration cycle circuit. Many ethylene-based fluoroolefins are characterized by low GWP. However, it is known that ethylene-based fluoroolefins can undergo disproportionation reactions when exposed to electrical discharges under high temperature and high pressure. The occurrence of a disproportionation reaction can cause a sudden increase in pressure within the refrigeration cycle circuit. Details of the working fluid will be described later.

[0011] The outdoor unit 10 includes a compressor 12, an outdoor heat exchanger 13, and an outdoor expansion valve 14. The compressor 12 is, for example, a scroll compressor that draws in, compresses, and discharges a gaseous working medium. The outdoor heat exchanger 13 is, for example, a fin-tube heat exchanger that drives an outdoor fan (not shown) to exchange heat between the working medium flowing therein and external air. The outdoor expansion valve 14 is a valve whose opening degree can be changed and reduces the pressure of the working medium passing through it.

[0012] The indoor unit 20 includes an indoor heat exchanger 21 and an indoor expansion valve 22. The indoor heat exchanger 21 is, for example, a fin-tube type heat exchanger, and drives an indoor fan (not shown) to exchange heat between the working medium flowing inside and the indoor air. The indoor expansion valve 22 is a valve whose opening and closing and opening degree can be changed.

[0013] [1-1-2. Compressor Configuration] FIG. 2 is a schematic diagram showing the compressor according to the first embodiment. As shown in FIG. 2, the compressor 12 is an internal intermediate pressure multi-stage compression rotary compressor. A drive motor 31 is housed in the upper interior portion of a cylindrical casing 30 made of steel plates. The drive motor 31 includes a stator 32 attached in an annular shape along the inner circumferential surface of the upper space of the casing 30, and a mover 33 inserted into the stator 32 with a gap therebetween. A rotating shaft 34 extending in the axial direction of the casing 30 is attached to the center of the mover 33. The stator 32 includes a lamination 35 formed by laminating annular electromagnetic steel plates and a magnet coil 36 wound around the lamination 35. The mover 33 includes a lamination 35 formed by laminating electromagnetic steel plates and a permanent magnet disposed within the lamination, although not shown.

[0014] 3 is a schematic diagram showing the electric wire 40 of the magnet coil 36 in the first embodiment. As shown in FIG. 3, the electric wire 40 constituting the magnet coil 36 is composed of a conductor 41 made of copper or the like and an insulating coating 42 that covers the outside of the conductor 41. The insulating coating 42 is formed of a resin such as polyester. In this embodiment, a conductive layer 43 is formed on the outside of the insulating coating 42. The conductive layer 43 is formed of, for example, a conductive resin, a resin mixed with a conductive filler, or metal vapor deposition.

[0015] One method for forming the conductive layer is to apply and harden an epoxy resin in which 10 to 30 wt % of carbon black is dispersed as a conductive filler. The substrate is not limited to epoxy resin, and polyester, polyesterimide, polyamideimide, polyimide, and the like can also be used. Carbon-based conductive fillers include carbon black, carbon nanofiber, carbon nanotubes, and graphene. Metal-based fillers include silver, copper, and nickel. Metal oxide-based fillers include indium oxide, zinc oxide, and tin oxide. Conductive polymer-based fillers include polyaniline, polythiophene, and polypyrrole. A conductive polymer may also be mixed into the substrate.

[0016] The conductive layer 43 may be formed over the entire magnet coil 36 after the electric wire 40 with the insulating coating 42 formed thereon is wound around the magnet coil 36, or the electric wire 40 may have the conductive layer 43 formed on the outside of the insulating coating 42 in advance.

[0017] A low-pressure side compression mechanism 50 and a high-pressure side compression mechanism 51 driven by a drive motor 31 are housed in the lower interior of the casing 30. The low-pressure side compression mechanism 50 is provided with a low-pressure side suction port 52 and a low-pressure side discharge port 53, and is configured to compress low-pressure refrigerant to an intermediate pressure. The high-pressure side compression mechanism 51 is provided with a high-pressure side suction port 54 and a high-pressure side discharge port 55, and is configured to compress intermediate-pressure refrigerant to a high pressure. The interior of the casing 30 is maintained at an intermediate pressure.

[0018] A low-pressure side discharge port 53 of the compressor 12 is connected to a high-pressure side suction port 54 of the compressor 12 via an intermediate pipe 56. A high-pressure side discharge port 55 of the compressor 12 is connected to the outdoor heat exchanger 13 via a refrigerant pipe 11.

[0019] [1-1-3. Working Medium] The working medium used in the air conditioner 1 is a working medium containing a fluoroolefin (fluoroalkene) such as an ethylene-based fluoroolefin. The specific type of fluoroolefin is not particularly limited, but examples include 1,1,2-trifluoroethylene (HFO1123), trans-1,2-difluoroethylene (HFO1132(E)), cis-1,2-difluoroethylene (HFO1132(Z)), 1,1-difluoroethylene (HFO1132a), tetrafluoroethylene (FO1114, TFE), monofluoroethylene (HFO1141), etc. fluoroethylene; 1,2,3,3,3-pentafluoropropene (HFO-1225ye), 2,3,3,3-tetrafluoropropene (HFO-1234yf), 1,3,3,3-tetrafluoropropene (HFO-1234ze), 1,2,3,3-tetrafluoropropene (HFO-1234ye), 3,3,3-trifluoropropene (HFO-1243zf), and the like.

[0020] The working fluid may contain two or more refrigerant components. That is, it may contain a fluoroolefin selected from the examples above (e.g., 1,1,2-trifluoroethylene) and a second refrigerant component. The second refrigerant component may be, but is not limited to, a hydrofluorocarbon (HFC), a hydrofluoroolefin (HFO), a saturated hydrocarbon, carbon dioxide, or another refrigerant.

[0021] Examples of the hydrofluorocarbon include fluoromethanes such as difluoromethane (R32) and trifluoromethane (R23), fluoroethane (R161), 1,1-difluoroethane (R152a), 1,1,1-trifluoroethane (R143a), 1,1,2,2-tetrafluoroethane (R134), 1,1,1,2-tetrafluoroethane (R134a), pentafluoroethane (R125), fluoroethanes such as difluoroethane and trifluoroethane, and 1,1,1,3,3-pentafluoropropane ( fluoropropanes such as 1,1,1,2,3,3-hexafluoropropane (R245fa), 1,1,1,2,3,3-hexafluoropropane (R236ea), 1,1,1,3,3,3-hexafluoropropane (R236fa), and 1,1,1,2,3,3,3-heptafluoropropane (R227ea); fluorobutanes such as 1,1,1,3,3-pentafluorobutane (R365mfc); and fluoropentanes such as 1,1,1,2,3,4,4,5,5,5-decafluoropentane (R4310mee) and heptafluorocyclopentane (Rc447ef).

[0022] Examples of saturated hydrocarbons include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), and methylcyclobutane, but other hydrocarbons may also be used. The second refrigerant component may contain multiple components. That is, the second refrigerant component may contain two or more refrigerant components selected from hydrofluorocarbons, hydrofluoroolefins, saturated hydrocarbons, carbon dioxide, and other refrigerants.

[0023] The working medium may be a refrigerant classified as mildly flammable (A2L), flammable (A2), or highly flammable (A3) according to ISO 817.

[0024] [1-1-4. Disproportionation Inhibitor] The working fluid used as a refrigerant in the air conditioner 1 may contain a disproportionation inhibitor in addition to the refrigerant components. The disproportionation inhibitor is, for example, a saturated hydrocarbon. The working fluid may contain a disproportionation inhibitor consisting of one or more components. Examples of saturated hydrocarbons used as disproportionation inhibitors include ethane, n-propane, cyclopropane, n-butane, cyclobutane, isobutane (2-methylpropane), methylcyclopropane, n-pentane, isopentane (2-methylbutane), neopentane (2,2-dimethylpropane), and methylcyclobutane, but other saturated hydrocarbons may also be used. A particularly preferred disproportionation inhibitor is n-propane.

[0025] The disproportionation inhibitor may be, for example, a haloalkane having 1 to 4 carbon atoms. The haloalkane used as the disproportionation inhibitor may be any haloalkane having 1 to 4 carbon atoms, excluding cases where all of the halogen atoms are fluorine. More specific examples include halomethanes (halogenated methanes) having 1 carbon atom, haloethanes (halogenated ethanes) having 2 carbon atoms, halopropanes (halogenated propanes) having 3 carbon atoms, and halobutanes (halogenated butanes) having 4 carbon atoms.

[0026] Specifically, the disproportionation-inhibiting haloalkane may be one having the structure of formula (1) shown below: CpHqXr (1)

[0027] However, X in formula (1) is a halogen atom selected from the group consisting of fluorine (F), chlorine (Cl), bromine (Br), and iodine (I). p is an integer of either 1 or 2. q is an integer of 0 or greater. r is an integer of 1 or greater. The sum of q and r is 2p+2. When r is 2 or greater, X are the same or different halogen atoms.

[0028] However, the disproportionation-inhibited haloalkanes represented by formula (1) above exclude those in which X is composed solely of F. This is because disproportionation-inhibited haloalkanes in which X is composed solely of F are compounds that can be used in combination with other refrigerant components, but do not substantially function as disproportionation inhibitors.

[0029] In the disproportionation-inhibited haloalkane represented by formula (1), the halogen atom X may be at least one of F, Cl, Br, and I, as described above, but is preferably at least I. When the number of carbon atoms is 2 (p=2) and the number of halogen atoms is 2 or greater (r≧2), the halogen atom X is preferably at least F and I.

[0030] The disproportionation-inhibiting haloalkane represented by formula (1) is not particularly limited, and specific examples thereof include (mono)iodomethane (CH3I), diiodomethane (CH2I2), dibromomethane (CH2Br2), bromomethane (CH3Br), dichloromethane (CH2Cl2), chloroiodomethane (CH2ClI), dibromochloromethane (CHBr2Cl), tetraiodomethane (CI4), carbon tetrabromide (CBr4), bromotrichloromethane (CBrCl3), dibromodichloromethane (CBr2Cl2), tribromofluoromethane (CBr3F), fluorodiiodomethane (CHFI), and the like. ), difluorodiiodomethane (CF2I2), dibromodifluoromethane (CBr2F2), trifluoroiodomethane (CF3I), and other halomethanes; 1,1,1-trifluoro-2-iodoethane (CF3CH2I), monoiodoethane (CH3CH2I), monobromoethane (CH3CH2Br), 1,1,1-triiodoethane (CH3CI3), 1-bromo-2-iodotetrafluoroethane (CF2BrCF2I), and other halomethanes.

[0031] The working fluid may contain a plurality of disproportionation inhibitors selected from the saturated hydrocarbons and haloalkanes. The working fluid may contain one type of saturated hydrocarbon, or two or more types of saturated hydrocarbons. The working fluid may contain one type of haloalkane, or two or more types of haloalkanes.

[0032] A preferred example of the working fluid is a mixture containing 1,1,2-trifluoroethylene and n-propane. This working fluid may contain the second refrigerant component described above, or may contain other components.

[0033] Each of the above working fluids may contain inevitable impurities, such as various additives including stabilizers added for the purpose of stabilizing the fluid during transportation or storage, residues or by-products of the raw materials used to synthesize the refrigerant components, and substances that are mixed in for other reasons.

[0034] The mass ratio of 1,1,2-trifluoroethylene to n-propane contained in the working fluid can be changed as appropriate. Thus, the contents (contents) of the fluoroolefin and other refrigerants, or the content (contents) of the disproportionation inhibitor in the mixed refrigerant are not particularly limited. For example, when the total amount of the mixed refrigerant is taken as 100% by mass, the fluoroolefin content may be 50% by mass or more, 60% by mass or more, 70% by mass or more, or even 80% by mass or more. Furthermore, when the total amount of the mixed refrigerant is taken as 100% by mass, the propane content may be less than 50% by mass, and may be 40% by mass or less, 30% by mass or less, or 20% by mass or less.

[0035] [1-2. Operation] Next, the operation of the first embodiment will be described. In this embodiment, the compressor 12 is driven to compress the working medium and discharge it toward the outdoor heat exchanger 13. The high-temperature, high-pressure working medium compressed by the compressor 12 exchanges heat with outdoor air in the outdoor heat exchanger 13, where it is condensed, and is expanded by the outdoor expansion valve 14. The working medium is then sent to the indoor expansion valve 22, where it is further expanded and sent to the indoor heat exchanger 21. The working medium exchanges heat with indoor air in the indoor heat exchanger 21, cools the indoor air, and is then returned to the compressor 12. Through this series of operations, the room can be cooled.

[0036] As shown in FIG. 3 , in the magnet coil 36 of the drive motor 31 of the compressor, an electric field concentrates in the contact vicinity region A between adjacent electric wires 40 because the relative dielectric constant of the working fluid is smaller than that of the insulating coating 42. Therefore, discharge may occur in the contact vicinity region A between adjacent electric wires 40. In the case of a working fluid containing an ethylene-based fluoroolefin, a disproportionation reaction may occur due to discharge. However, in this embodiment, the conductive layer 43 is formed on the outside of the insulating coating 42. Therefore, contact between the conductive layers 43 of the electric wires 40 reduces the potential difference in the contact vicinity region A, thereby suppressing the occurrence of discharge in the contact vicinity region A.

[0037] [1-3. Effects, etc.] As described above, the compressor 1 in this embodiment is a compressor that uses a working fluid containing an ethylene-based fluoroolefin and performs air conditioning by driving an electric motor to circulate the working fluid within a refrigerant circuit, and has a conductive layer 43 formed on the outside of the insulating coating 42 of the electric wires 40 that constitute the magnet coil 36 of the electric motor. As a result, since the conductive layer 43 is formed on the outside of the insulating coating 42, the conductive layers 43 of the electric wires 40 come into contact with each other, which reduces the potential difference in the contact vicinity region A and suppresses the occurrence of discharge in the contact vicinity region A. This makes it possible to suppress the occurrence of a disproportionation reaction of the working fluid.

[0038] Furthermore, in the compressor 1 of this embodiment, the conductive layer 43 is formed in advance on the outside of the insulating coating 42 of the electric wire 40 before the magnet coil 36 is formed. As a result, even if the conductive layer 43 is formed in advance on the outside of the insulating coating 42 of the electric wire 40, the potential difference in the contact portion vicinity region A can be reduced and the occurrence of discharge in the contact portion vicinity region A can be suppressed. Therefore, the occurrence of a disproportionation reaction of the working fluid can be suppressed.

[0039] (Embodiment 2) Next, a second embodiment of the present disclosure will be described. In this embodiment, when forming the conductive layer 43, first, the magnet coil 36 is installed using an electric wire 40 having only an insulating coating 42, and in this state, a performance test of the magnet coil 36, such as a dielectric strength test or an impulse response test, is performed on the magnet coil 36. Then, based on the results of the performance test, the conductive layer 43 is formed on the magnet coil 36. By forming the conductive layer 43 on the magnet coil 36 based on the performance test in this way, the conductive layer 43 is formed only on magnet coils 36 that are good products that satisfy the performance test, and therefore waste in manufacturing can be reduced.

[0040] Here, in the magnet coil 36, the coil ends (portions protruding above and below the stator 32) are prone to deterioration of the insulating coating 42 for reasons such as the conductor wires 41 being bent during coil formation, causing deformation of the insulating coating 42, adjacent conductor wires 41 rubbing against each other due to vibration caused by current flow, and the exposed portions being exposed outside the slots in the stator 32 and therefore potentially coming into contact with foreign matter. However, by forming a conductive layer 43 also on the coil ends, deterioration due to partial discharge is prevented, and the insulating coating 42 is further covered and displacement relative to the adjacent conductor wires 41 is restricted, making it possible to suppress deterioration of the insulating coating 42.

[0041] Furthermore, the conductive layer 43 can be formed, for example, by bringing the stator 32 and the conductor 41 with the insulating coating 42 into contact with a liquid conductive resin or a resin mixed with a conductive filler, allowing the resin to penetrate and fill the spaces between the conductor 41, and then solidifying to form the conductive layer 43. The conductive layer 43 can be formed on the coil end of the magnet coil 36 by applying a liquid conductive resin or a resin mixed with a conductive filler to the coil end of the magnet coil 36 and drying it to form the conductive layer 43. By forming the conductive layer 43 in this manner, the conductive layer 43 can be easily formed.

[0042] As described above, in the compressor 1 of this embodiment, the electric wire 40 having only the insulating coating 42 is used, and in a state where the magnet coil 36 is installed, a performance test of the magnet coil 36 is conducted, and then the conductive layer 43 is formed on the magnet coil 36. In this way, the conductive layer 43 can be formed in accordance with the performance of the magnet coil 36.

[0043] (Other Embodiments) As described above, the first and second embodiments have been described as examples of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to these and can be applied to embodiments in which modifications, substitutions, additions, omissions, etc. are made. Furthermore, it is also possible to combine the components described in the first and second embodiments to create new embodiments.

[0044] [Configurations Supported by the Above-described Embodiments] The above-described embodiments support the following configurations.

[0045] (Additional Notes) (Technology 1) A compressor for air conditioning using a working fluid containing an ethylene-based fluoroolefin and circulating the working fluid in a refrigerant circuit by driving an electric motor, wherein a conductive layer is formed on the outside of the insulating coating of the electric wires constituting the magnet coil of the electric motor. According to this configuration, since the conductive layer is formed on the outside of the insulating coating, contact between the conductive layers of the electric wires can reduce the potential difference in the area near the contact points, thereby suppressing the occurrence of discharge in the area near the contact points. This can suppress the occurrence of a disproportionation reaction in the working fluid.

[0046] (Technology 2) The compressor according to Technology 1, in which a conductive layer is formed on the outer surface of the insulating coating of the electric wire before the magnet coil is formed. With this configuration, even if a conductive layer is formed on the outer surface of the insulating coating of the electric wire beforehand, the potential difference in the region near the contact portion can be reduced, and the occurrence of discharge in the region near the contact portion can be suppressed. Therefore, the occurrence of a disproportionation reaction of the working fluid can be suppressed.

[0047] The present disclosure is suitable for use in a compressor that uses a working fluid containing an ethylene-based fluoroolefin, is capable of suppressing discharge in the conductor portion of a magnet coil, and is capable of suppressing the occurrence of a disproportionation reaction in the working fluid.

[0048] REFRIGERATION CYCLE DEVICE 10 OUTDOOR UNIT 11 REFRIGERANTE PIPE 12 COMPRESSOR 13 OUTDOOR HEAT EXCHANGER 14 OUTDOOR EXPANSION VALVE 20 INDOOR UNIT 21 INDOOR HEAT EXCHANGER 22 INDOOR EXPANSION VALVE 30 CASING 31 DRIVE MOTOR 32 STATOR 33 MOVING POINT 34 ROTATING SHAFT 35 LAYER 36 MAGNET COIL 40 ELECTRIC WIRE 41 CONDUCTOR 42 INSULATED COVER 43 CONDUCTIVE LAYER 50 LOW-PRESSURE SIDE COMPRESSION MECHANISM 51 HIGH-PRESSURE SIDE COMPRESSION MECHANISM 52 LOW-PRESSURE SIDE SUPPLY 53 LOW-PRESSURE SIDE SUPPLY 54 HIGH-PRESSURE SIDE SUPPLY 55 HIGH-PRESSURE SIDE SUPPLY 56 INTERMEDIATE PIPE

Claims

1. A compressor for air conditioning by using a working medium containing an ethylene-based fluoroolefin and circulating the working medium in a refrigerant circuit by driving an electric motor, wherein a conductive layer is formed on the outside of the insulating coating of an electric wire that constitutes a magnet coil of the electric motor.

2. The compressor according to claim 1, wherein a conductive layer is formed on the outside of the insulating coating of the electric wire before the magnet coil is formed.

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