Patent Application
20210222916
A refrigeration cycle apparatus for use in, for example, a cooling operation or a heating operation.
Patent Literature 1 (Japanese Patent No. 4,932,793) discloses a refrigeration cycle apparatus that adopts HFO-1234yf as a refrigerant.
Some components for use in a refrigeration cycle apparatus may include a resin material. Some types of resin materials generate an acid by chemically reacting with a refrigerant. The acid thus generated may induce corrosion or degradation of such components.
A refrigeration cycle apparatus according to a first aspect includes a refrigerant and a refrigeration cycle circuit. The refrigeration cycle circuit includes a compressor, and causes the refrigerant to circulate therethrough. The refrigerant is HFO-based refrigerant alone or a mixed refrigerant. In the mixed refrigerant, a mixing ratio of HFO-based refrigerant is equal to or more than 10% by weight. The compressor includes a motor. The motor includes a first resin component. The first resin component is made of at least one of PET (polyethylene terephthalate), PA (polyamide), LCP (liquid crystal polymer), PBT (polyethylene terephthalate), phenol resin, melamine resin, PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), PAI (polyamideimide), PPS (polyphenylene sulfide), and PEN (polyethylene naphthalate).
According to this configuration, the motor includes the first resin component made of a resin other than PI (polyimide). Accordingly, the first resin component generates less amount of acid by reacting with the HFO-based refrigerant, compared with the case where the first resin component was made of PI. As a result, corrosion by the acid of the components in a refrigeration cycle system is restrained.
The refrigeration cycle apparatus according to a second aspect is the refrigeration cycle apparatus according to the first aspect, wherein a ratio of the first resin component to the refrigerant is equal to or more than 1.5% by weight.
According to this configuration, the ratio of the first resin component to the refrigerant is equal to or more than 1.5% by weight. This configuration therefore restrains acid generation since the first resin component with a larger amount is less likely to react with the HFO-based refrigerant.
The refrigeration cycle apparatus according to a third aspect is the refrigeration cycle apparatus according to the first or second aspect, further including a refrigerating machine oil and an acid scavenger. The refrigerating machine oil is retained in the compressor. The acid scavenger is added to the refrigerating machine oil. A ratio of the acid scavenger to the refrigerant is equal to or less than 1.6% by weight.
According to this configuration, the ratio of the acid scavenger to the refrigerant is equal to or less than 1.6% by weight. This configuration therefore restrains degradation in lubricity of the refrigerating machine oil owing to the acid scavenger.
The refrigeration cycle apparatus according to a fourth aspect is the refrigeration cycle apparatus according to any one of the first to third aspects, wherein the first resin component is at least one selected from an insulator, an insulating sleeve, a binding cord, a cluster block, a covering of a connection line, and a covering of an outgoing line in the motor.
According to this configuration, a component for use in the motor is made of a resin other than PI. This configuration therefore restrains acid generation in the motor, and then restrains corrosion of the motor.
The refrigeration cycle apparatus according to a fifth aspect is the refrigeration cycle apparatus according to the fourth aspect, wherein the first resin component includes the insulator of the motor.
According to this configuration, the insulator of the motor is made of a resin other than PI. This configuration therefore restrains acid generation since the insulator which occupies a certain volume is less likely to react with the HFO-based refrigerant.
The refrigeration cycle apparatus according to a sixth aspect is the refrigeration cycle apparatus according to any one of the first to fifth aspects, further including a sliding portion made of at least one of PA (polyamide), PAI (polyamideimide), PPS (polyphenylene sulfide), PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), and DLC (diamond-like carbon).
According to this configuration, a coating material for the sliding portion is a material other than PI. This configuration therefore restrains acid generation in the sliding portion, and then restrains corrosion of the sliding portion.
The refrigeration cycle apparatus according to a seventh aspect is the refrigeration cycle apparatus according to any one of the first to sixth aspects, wherein the motor further includes a second resin component. The second resin component includes PI (polyimide). A ratio of the second resin component to the refrigerant is less than 1.5% by weight.
According to this configuration, the ratio of the second resin component to the refrigerant is less than 1.5% by weight. This configuration therefore restrains acid generation since the ratio of the second resin component to the refrigerant is small.
The refrigeration cycle apparatus according to an eighth aspect is the refrigeration cycle apparatus according to the seventh aspect, wherein the motor includes an electric wire covered with an insulating covering, an insulating sheet, and a varnish. The second resin component includes at least one of the insulating covering, the insulating sheet, and the varnish.
According to this configuration, the second resin component includes at least one of the insulating covering, the insulating sheet, and the varnish. This configuration therefore suppresses degradation in heat resistance of the motor.
(1) General Configuration
(1-1) Refrigerant
The refrigerant is an HFO-based refrigerant alone or a mixed refrigerant. In a case where the refrigerant is a mixed refrigerant, a mixing ratio of the HFO-based refrigerant in the mixed refrigerant is equal to or more than 10% by weight, preferably equal to or more than 14% by weight. Examples of the refrigerant to be used herein may include Refrigerants 1 to 75 listed in the following table.
(1-2) Refrigeration Cycle Circuit
The refrigeration cycle circuit includes a compressor 10, a four-way switching valve 3, a heat source-side heat exchanger 4, an expansion valve 5, and a usage-side heat exchanger 6. A configuration of the compressor 10 will be described later.
When the four-way switching valve 3 establishes a connection illustrated with solid lines in
The expansion valve 5 has a sliding portion. The sliding portion of the expansion valve 5 is coated with a coating material. The coating material may be, for example, a material other than PI (polyimide). Specific examples of the coating material may include PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), and DLC (diamond-like carbon).
(2) Specific Configuration of Compressor 10
The compressor 10 shown in
(2-1) Casing 20
The casing 20 is a cylindrical container extending horizontally in the figures. The casing 20 has an internal space divided into a low-pressure space 51 and a high-pressure space S2. A refrigerating machine oil L is retained on a lower side of the high-pressure space S2. The refrigerating machine oil L is fed to sliding portions in the compressor 10 through unillustrated oil feed paths.
A suction port 25 is provided on the side of the low-pressure space 51 of the casing 20. A discharge port 26 is provided on the side of the high-pressure space S2 of the casing 20. The low-pressure gas refrigerant is sucked into the compressor 10 through the suction port 25. The high-pressure gas refrigerant is discharged from the compressor 10 through the discharge port 26.
(2-2) Motor 30
The motor 30 is disposed in the low-pressure space S1. As illustrated in
The stator 31 includes a stator core 31a, an insulator 31b, coil windings 31c, insulating sheets 31d, insulated electric wires 31e, an insulating sleeve 31f, a binding cord 31g, a cluster block 31h, connection lines, outgoing lines, and a varnish.
The stator core 31a includes a stack of steel plates. The insulator 31b is made of a resin, and is disposed on an end face of the stator core 31a. The coil winding 31c is made of a conductive material, and is wound around the stator core 31a and the insulator 31b. The insulating sheet 31d is made of a resin, and is provided in, for example, a slot between adjacent coil windings 31c. The insulated electric wires 31e is an electric wire covered with an insulating covering. The insulating sleeve 31f is made of a resin, and insulates a joint between the insulated electric wires 31e from the surroundings. The binding cord 31g is made of a resin, and fixes the insulated electric wires 31e to the insulator 31b. The cluster block 31h is a connector housing made of a resin, and detachably connects a plurality of the insulated electric wires 31e. The connection lines are used for supplying external power to the motor 30. The connection lines are covered with a covering. The outgoing lines are lead wires extending from the coil winding 31c. The outgoing lines are covered with a covering. The varnish is used for hardening the coil winding 31c.
The insulator 31b, the insulating sheet 31d, the covering of the insulated electric wire 31e, the insulating sleeve 31f, the binding cord 31g, the cluster block 31h, the covering of the connection line, the covering of the outgoing line, and the varnish are resin components. At least one of the covering of the insulated electric wire 31e, the insulating sheet 31d, and the varnish is made of a material including PI (polyimide). The covering of the insulated electric wire 31e may be made of PI for enhancing the strength. The insulating sheet 31d and the varnish may be made of PI for enhancing heat resistance. The insulator 31b, the insulating sleeve 31f, the binding cord 31g, the cluster block 31h, the covering of the connection line, and the covering of the outgoing line are made of a resin material other than PI. Examples of the resin material other than PI may include PET (polyethylene terephthalate), PA (polyamide), LCP (liquid crystal polymer), PBT (polyethylene terephthalate), phenol resin, melamine resin, PEEK (polyether ether ketone), PTFE (polytetrafluoroethylene), PAI (polyamideimide), PPS (polyphenylene sulfide), and PEN (polyethylene naphthalate).
For example, the insulator 31b includes PA, LCP, or PBT. For example, the insulating sleeve 31f includes PET or PA. For example, the binding cord 31g includes PET. For example, the cluster block 31h includes PBT, phenol resin, or melamine resin.
A ratio of the components each made of a resin material other than PI to the refrigerant is equal to or more than 1.5% by weight.
A ratio of the components each made of a resin material including PI to the refrigerant is less than 1.5% by weight.
(2-3) Shaft 40
Referring back to
(2-4) Compression Mechanism 50
The compression mechanism 50 compresses the low-pressure gas refrigerant to generate the high-pressure gas refrigerant. The compression mechanism 50 includes a cylinder 51, a screw rotor 52, gate rotors 53, and gate rotor supporting portions 54.
(2-4-1) Cylinder 51
The cylinder 51 is formed as a part of the casing 20. The cylinder 51 accommodates therein the screw rotor 52. The cylinder 51 has a gap through which gates 53a, which will be described later, pass.
(2-4-2) Screw Rotor 52
The screw rotor 52 is a metal member having a substantially columnar shape. The screw rotor 52 is coupled to the shaft 40. The screw rotor 52 is rotatable together with the shaft 40. The screw rotor 52 has an outer diameter that is slightly smaller than the inner diameter of the cylinder 51.
(2-4-3) Gate Rotor 53
Each of the gate rotors 53 has a plurality of gates 53a extending radially. The gate 53a passes through the gap in the cylinder 51 and meshes with the spiral grooves 52a of the screw rotor 52. The screw rotor 52 receives rotational force from the shaft 40 to rotate, and the spiral grooves 52a thus move in accordance with the rotation of the screw rotor 52. The gates 53a move in accordance with the movement of the spiral grooves 52a, and the gate rotors 53 thus rotate in accordance with the movement of the gates 53a.
(2-4-4) Gate Rotor Supporting Portion 54
Each of the gate rotor supporting portions 54 supports the corresponding gate rotor 53 in a rotatable manner. The two gate rotor supporting portions 54 are arranged symmetrically with each other with respect to the rotational axis of the screw rotor 52.
(2-5) Others
The screw rotor 52 slides relative to the cylinder 51 and the gate rotors 53. These sliding portions may be coated with a coating material. Examples of the coating material may include PEEK, PTFE, and DLC.
(3) Compression Operation
With reference to
(4) Refrigerating Machine Oil L
The refrigerating machine oil L is a lubricating oil for avoiding wear and seizure of the sliding portions in the compressor 10. The refrigerating machine oil L mainly includes a base oil, an acid scavenger, an extreme pressure agent, and an antioxidant.
(4-1) Base Oil
Examples of the base oil may include mineral oils and synthetic oils. The base oil to be appropriately selected herein has favorable compatibility with the refrigerant used in the refrigeration cycle apparatus 1. Examples of the mineral oil may include a naphthene-based mineral oil and a paraffin-based mineral oil. Examples of the synthetic oil may include ester compounds, ether compounds, poly-α-olefin, and alkylbenzene. Specific examples of the synthetic oil may include polyvinyl ether, polyol ester, and polyalkylene glycol. In this embodiment, preferably, the base oil is a synthetic oil such as polyvinyl ether or polyol ester. Alternatively, the base oil may be mixture of at least two kinds of the mineral oils or synthetic oils mentioned above.
(4-2) Acid Scavenger
The acid scavenger is an additive that reacts with an acid resulting from decomposition of a refrigerant to restrain degradation of the refrigerating machine oil L owing to the acid.
Examples of the acid scavenger may include epoxy compounds, carbodiimide compounds, and tenpene-based compounds. Specific examples of the acid scavenger may include 2-ethylhexyl glycidyl ether, phenyl glycidyl ether, epoxidized cyclohexylcarbinol, di(alkylphenyl)carbodiimide, and β-pinene.
(4-3) Extreme Pressure Agent
The extreme pressure agent is an additive for avoiding wear and seizure of the sliding portions. The refrigerating machine oil L forms an oil membrane between surfaces of the members sliding relative to each other at the sliding portions, thereby preventing the sliding members from contacting each other. In a case where a refrigerating machine oil L with low viscosity, such as a polyvinyl ether, is used and in a case where high pressure is applied to the sliding members, the sliding members are apt to come into contact with each other. The extreme pressure agent forms a coating by reacting with the surfaces of the members sliding relative to each other at the sliding portions, thereby suppressing occurrence of wear and seizure. Examples of the extreme pressure agent may include phosphate ester, phosphite ester, thiophosphate, sulfurated ester, sulfide, and thiobisphenol. Specific examples of the extreme pressure agent may include tricresyl phosphate (TCP), triphenyl phosphate (TPP), triphenyl phosphorothioate (TPPT), amines, C11-14 side chain alkyl, monohexyl phosphate, and dihexyl phosphate. TCP attaches to a surface of a sliding member and decomposes the sliding member, thereby forming a phosphate coating.
(4-4) Antioxidant
The antioxidant is an additive for avoiding oxidation of the refrigerating machine oil L. Specific examples of the antioxidant may include zinc dithiophosphate, organic sulfur compound, phenol-based antioxidants such as 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol, and 2,2′-methylenebis(4-methyl-6-tert-butylphenol), amine-based antioxidants such as phenyl-α-naphthylamine and N,N′-di-phenyl-p-phenylenediamine, and N,N′-disalicylidene-1,2-diaminopropane.
(4-5) Mixing Ratio
The refrigerating machine oil L includes the acid scavenger, for example, as much as 1.0% by weight or more. The acid scavenger thus restrains degradation of the refrigerating machine oil L and corrosion of the expansion valve 5 owing to an acid. The acid scavenger also restrains corrosion of other components of the refrigeration cycle apparatus 1. Therefore, the use of the refrigerating machine oil L according to this embodiment improves the reliability of the refrigeration cycle apparatus 1.
The ratio of the acid scavenger to the refrigerant is equal to or less than 1.6% by weight. This ratio restrains degradation in lubricity of the refrigerating machine oil L.
(5) Features
(5-1)
The inventors have found that PI is apt to generate an acid by reacting with HFO-based refrigerant. The insulating components of the motor 30 (i.e. the insulator 31b, the insulating sleeve 31f, the binding cord 31g, the cluster block 31h, the covering of the connection line, and the covering of the outgoing line) are each made of a resin other than PI. These insulating components generate less amount of acid by reacting with the HFO-based refrigerant, compared with the case where these insulating components were made of PI. Therefore, corrosion by an acid of the components in a refrigeration cycle system is restrained.
(5-2)
The ratio of the insulating components made of a resin other than PI (i.e., the insulator 31b, the insulating sleeve 31f, the binding cord 31g, the cluster block 31h, the covering of the connection line, the covering of the outgoing line) to the refrigerant is equal to or more than 1.5% by weight. This configuration therefore restrains acid generation since the insulating components with a larger amount are less likely to react with the HFO-based refrigerant.
(5-3)
The ratio of the acid scavenger to the refrigerant is equal to or less than 1.6% by weight. This configuration therefore restrains degradation in lubricity of the refrigerating machine oil L owing to the acid scavenger.
(5-4)
The components for use in the motor 30 (i.e. the insulator 31b, the insulating sleeve 31f, the binding cord 31g, the cluster block 31h, the covering of the connection line, and the covering of the outgoing line) are made of a resin other than PI. This configuration therefore restrains acid generation in the motor 30, and then restrains corrosion of the motor 30.
(5-5)
The insulator 31b of the motor 30 is made of a resin other than PI. This configuration therefore restrains acid generation since the insulator 31b which occupies a certain volume is less likely to react with the HFO-based refrigerant.
(5-6)
A material other than PI is used at the sliding portions, such as the coating material for the expansion valve 5 or the sliding bearing of the shaft 40. This configuration therefore restrains acid generation in the sliding portions, and then restrains corrosion of the sliding portions.
(5-7)
A part of the motor 30 is made of a resin including PI, and the ratio of the resin including PI to the refrigerant is less than 1.5% by weight. This configuration therefore restrains acid generation since the ratio of the components including PI to the refrigerant is small.
(5-8)
At least one of the insulating covering, the insulating sheet 31d, and the varnish includes PI. This configuration therefore suppresses degradation in heat resistance of the motor 30.
(6) Modifications
(6-1) First Modification
In the foregoing embodiment, at least one of the covering of the insulated electric wire 31e, the insulating sheet 31d, and the varnish includes PI. Alternatively, the covering of the insulated electric wire 31e, the insulating sheet 31d, and the varnish may not include PI. For example, the covering of the insulated electric wire 31e, the insulating sheet 31d, and the varnish may be made of a resin other than PI.
With this configuration, the refrigeration cycle apparatus 1 is less likely to generate an acid.
(6-2) Second Modification
In the foregoing embodiment, the compressor 10 is of a screw-type compressor. Alternatively, the compressor may be of another type such as a scroll-type compressor or a rotary-type compressor.
The foregoing description concerns embodiments of the disclosure. It will be understood that numerous modifications and variations may be made without departing from the gist and scope of the disclosure in the appended claims.
Patent Literature 1: Japanese Patent No. 4,932,793
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-096360 | May 2018 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2019/019323 | 5/15/2019 | WO | 00 |
