JP2002227767A - Hermetic compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic compressor capable of having efficient operation by suppressing a leakage current even if a coolant containing no chlorine group in its molecule is used. SOLUTION: In this hermetic compressor, a stator winding 8 formed by being directly wound around the teeth part 12 of a stator core through an insulating material 15 is provide, a coolant in a H F C group is used for its coolant, and refrigerating machine oil 41 having no mutual solubility or having weak compatibility relative to the coolant is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic compressor used for, for example, refrigeration / air-conditioning equipment, and more particularly to an HF compressor.
The present invention relates to improvement of leakage current when C refrigerant is used.

[0002]

2. Description of the Related Art FIG.
FIG. 1 is a refrigerant circuit diagram showing an example of a refrigerant circulation system using a conventional hermetic compressor disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, in which a refrigeration / air-conditioning apparatus is shown. In the figure, 51 is a hermetic compressor whose rotation speed can be controlled by inverter driving, 52 is a four-way valve that switches the flow of refrigerant during cooling and heating, 53 is an outdoor heat exchanger that is a heat source side heat exchanger, and 54 is An electronic expansion valve 55 serving as a throttle mechanism is an indoor heat exchanger serving as a use-side heat exchanger, and these are sequentially connected by a refrigerant pipe. 61
Is a compressor drive device for controlling the rotation speed of the hermetic compressor 51 by an inverter drive circuit.

Reference numeral 56 denotes an outdoor blower fan, 62 denotes an outdoor blower fan driving device, 64 denotes an outdoor microcomputer controller, 57
Is an indoor blowing fan, 63 is an indoor blowing fan drive, 6
Reference numeral 5 denotes an indoor microcomputer control unit. A broken line 81 indicates a block constituting an outdoor unit, and a broken line 82 indicates a block constituting an indoor unit. Further, in this refrigerant circulation system, HFC410A, which is a mixed refrigerant of HFC32 and HFC125, is used as a refrigerant, and an alkylbenzene-based oil having low mutual compatibility with HFC410A is used as a refrigerating machine oil.

FIG. 6 is a longitudinal sectional view showing the conventional hermetic compressor 51 described above. Reference numeral 1 denotes a closed container.
Inside, the motor unit 2 is housed in the upper part, and the compressor unit 3 is housed in the lower part. 4 is the motor section 2 and the compressor section 3
Is a rotating shaft that connects. The electric motor unit 2 includes a rotor 5 inserted into the rotating shaft 4 and a stator 9 having a built-in winding 8 having coil end portions 6 and 7 at both ends. The stator 9 is held in a state of directly contacting the closed container 1 by shrink fitting or the like.

FIG. 7 is a plan view showing the structure of the stator 9. Reference numeral 10 denotes a stator core, and a back yoke portion 11
And a teeth portion 12 integrally protruding from the inner peripheral wall of the back yoke portion 11 at a predetermined interval. Slots 13 are formed between the teeth 12, and the windings 8 are provided across the slots 13 by an inserter winding method. Incidentally, reference numeral 14 denotes a permanent magnet constituting a part of the rotor 5.

In the refrigerant circulation system using the conventional hermetic compressor configured as described above, power is supplied from an external commercial power supply to the motor section 2 of the hermetic compressor 51 via the compressor driving device 61. The compressor unit 3 is supplied and driven. The refrigerant compressed by the compressor unit 3 flows in a direction shown by a solid arrow in FIG.
5. The operation is performed through the electronic expansion valve 54, the outdoor heat exchanger 53, and the four-way valve 52 in order to return to the hermetic compressor 51, thereby heating the room. On the other hand, at the time of cooling, the four-way valve 52 is switched and operated so that the compressed refrigerant flows in the direction of the dashed arrow, and indoor cooling is performed by using the indoor heat exchanger 55 as an evaporator.

[0007] In the hermetic compressor 51, a leakage current is generated through the refrigerating machine oil attached to the electric motor unit while a voltage is applied to the electric motor unit 2. When the refrigerant dissolution rate in the refrigerating machine oil increases, the amount of the refrigerant having a large relative permittivity dissolved in the refrigerating machine oil increases, so that the leakage current increases. In addition, as the surface area of the motor unit, which is determined by the thickness of the iron core of the motor unit, the coil end height, and the like, increases, the amount of refrigerating machine oil attached to the motor unit increases, so that the leakage current increases. Further, when the motor section of the hermetic compressor is operated by varying the rotation speed by an inverter drive circuit, increasing the carrier frequency improves the efficiency of the motor section, but increases the leakage current.

FIG. 8 is a graph showing superheat (difference between the temperature of the refrigerating machine oil in the closed vessel of the compressor and the saturated liquid temperature of the refrigerant under the pressure condition in the closed vessel) and leakage of the refrigerating machine oil when the refrigerant and the refrigerating machine oil are mixed. FIG. 4 is a characteristic diagram showing a relationship with a current. In the figure,
The curve a shows the case where HFC410A (R410A) is used as the refrigerant and the alkylbenzene-based oil is used as the refrigerating machine oil, and the curve b shows the case where HCFC22 (R22) + (alkylbenzene oil + mineral oil) is used.

In a refrigeration cycle using HFC410A as a refrigerant and an alkylbenzene-based oil as a refrigeration oil, the relative permittivity of the refrigerant itself is higher than HCFC22. Then, the leakage current is HCFC22 +
Although it is larger than the refrigeration cycle of (alkylbenzene oil + mineral oil), since the mutual solubility of the refrigerating machine oil in the refrigerant is small, the leakage current does not increase significantly even under the condition of a small superheat of the refrigerating machine oil. On the other hand, HCFC
22. In the refrigerating cycle using alkylbenzene oil + mineral oil as the refrigerating machine oil, the relative permittivity of the refrigerant itself is smaller than that of HFC410A refrigerant. As shown by the curve b, the relative permittivity when the refrigerant and the refrigerating machine oil are mixed is small, and the leakage current is small. Conversely, when the superheat of the refrigerating machine oil decreases, the refrigerant has a characteristic that the dissolution rate of the refrigerant in the refrigerating machine oil increases and the leakage current greatly increases.

In the conventional refrigeration cycle using the HFC410A + alkylbenzene oil, the refrigeration rate of the refrigerant in the normal operating temperature range of 10 deg. Superheat 10 deg in the refrigeration cycle of HCFC22 + (alkylbenzene oil + mineral oil), which has a proven leakage current in the same temperature range, while suppressing the decrease in viscosity of the refrigeration oil due to its dissolution into the machine oil.
It is suppressed below the value of time.

[Problems to be solved by the invention]

However, in a normal operating range of 10 degrees or more of superheat of refrigeration oil, this HFC4
Since the leakage current of the refrigeration cycle of 10A + alkylbenzene oil is larger than that of the conventional refrigeration cycle of HCFC22 + (alkylbenzene oil + mineral oil),
The carrier frequency of the inverter drive circuit cannot be increased to improve the efficiency of the motor section.

[0012] Further, instead of HFC410A as a refrigerant, a single HFC32 or a HFC32
When an HFC mixture with a high content of
32 has a higher dielectric constant than HFC410A,
The leakage current of the refrigeration cycle of C32 + alkylbenzene oil is greater than that of HFC410A + alkylbenzene oil refrigeration cycle, and the proven superheat 10 of HCFC22 + (alkylbenzene oil + mineral oil) refrigeration oil
The leakage current value at the time of deg will be exceeded.

In a refrigerating air conditioner, a superheat of refrigerating machine oil of 10 deg.
The following abnormal operation may be performed, and during this abnormal operation, the leakage current increases, and the HCFC22 +
There has been a problem that the leakage current of the refrigerating machine oil of (alkylbenzene oil + mineral oil) at the time of superheat of 10 deg will be exceeded, which may adversely affect peripheral electric and electronic devices.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and the leakage current is suppressed even if a refrigerant containing no chlorine group in the molecule is used, so that the hermetic compression can be operated efficiently. The purpose is to get a chance.

[0015]

SUMMARY OF THE INVENTION A hermetic compressor according to the present invention includes a stator winding directly wound around teeth portions of a stator core via an insulating material, and an HFC-based refrigerant as a refrigerant. A refrigerant is used, and a refrigerating machine oil having no mutual solubility or weak compatibility with the refrigerant is used as the refrigerating machine oil.

Further, the insulating material is made of a resin molding material provided so as to surround the teeth portion.

Further, the stator winding is formed by resin molding.

Further, the electric motor unit and the compressor unit are supported by a closed container via an elastic supporting member with a gap therebetween.

Further, the compressor section is provided with a liquid injection circuit.

Further, as the insulating material, at least one synthetic resin selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, and liquid crystal polymer is used.

Further, HFC32 or HF is used as a refrigerant.
A mixture containing C32 was used.

Further, as the refrigerating machine oil, a single substance or a mixture of an alkylbenzene-based oil, a polyalpha-olefin-based oil, a naphthenic-based mineral oil, and a paraffin-based mineral oil is used.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 of the Invention FIG. 1 is a longitudinal sectional view showing a hermetic compressor according to Embodiment 1 of the present invention. Reference numeral 51 denotes a hermetic compressor.
Reference numeral 1 denotes, for example, a refrigerant circulation system of a refrigerating air conditioner. In this refrigerant circulation system, as a refrigerant (not shown), an HFC-based refrigerant containing no chlorine group in a molecule is used, and particularly preferably, a single HFC32 or HF is used.
An HFC mixture containing C32 as a main component is used. As the HFC mixture, for example, HFC410A (HFC
32 / HFC125 mixture), HFC407C (HF
A mixture of C32 / HFC125 / HFC134a) is preferably used.

An electric motor unit 2 is accommodated in the upper part of the sealed container 1 and a compressor unit 3 is accommodated in the lower part. The electric motor unit 2 and the compressor unit 3 are connected via a rotary shaft 4. Refrigeration oil 41 is stored in the bottom of the closed container 1. As the refrigerating machine oil 41, those having no mutual solubility or weak compatibility with the HFC refrigerant can be preferably used,
For example, HFC32, HFC410A, and HFC407
An alkylbenzene-based oil having low mutual solubility with C;
A single substance of a polyalpha-olefin-based oil, a naphthenic-based mineral oil, and a paraffin-based mineral oil or a mixture of any two or more of them can be used.

The compressor unit 3 has a cylinder 21, a rolling piston 23 eccentrically rotating in the cylinder 21 by an eccentric part 22 of the rotating shaft 4, and constantly presses the rolling piston 23 against elastic means (not shown). And a frame 27 having bearing portions 25 and 26 of the rotary shaft 4 and a cylinder head 28, and a cylinder chamber 24 serving as a compression chamber with both ends closed in the cylinder 21. And a discharge muffler 30 forming a discharge muffling chamber 29 provided at the upper part of the discharge muffler 27.

A suction pipe 31 is connected to the cylinder chamber 24 in the cylinder 21, and is connected to an evaporator (neither is shown) constituting a refrigerant circulation system by a refrigerant pipe. On the other hand, a discharge pipe 32 is connected to an upper part of the closed vessel 1, and the discharge pipe 32 is connected to a condenser (neither is shown) constituting a refrigerant circulation system by a refrigerant pipe. A throttle mechanism (not shown) is provided between the evaporator (not shown) and the condenser (not shown).
-A condenser-a throttle mechanism-sequentially connected to an evaporator, for example, a refrigerant circulation system of an air conditioning refrigeration system similar to the conventional system shown in Fig. 5 is configured.

The motor section 2 is composed of a rotor 5 inserted into the rotating shaft 4 and a stator 9 having a winding 8 having coil end portions 6 and 7 at both ends. This motor unit 2
Is operated at a variable speed by an inverter drive circuit (not shown), and its rotation speed is always controlled to an optimum state according to the load.

FIG. 2 is a plan view showing the structure of the stator 9. The stator core 10 in which the steel plates are laminated includes a back yoke portion 11 and a tooth portion 12 integrally projecting from the inner peripheral wall portion of the back yoke portion 11 at a predetermined interval. The winding 8 is applied directly via a cable 15 (not shown in FIG. 2). The windings 8 are independently wound around the respective teeth portions 12. Here, this winding method is referred to as a “teeth portion direct winding method”. Specifically, a method in which the winding 8 is wound after the insulator 15 is inserted into the tooth portion 12,
After winding the winding 8, there is a method in which the wound insulator 15 is inserted into the teeth portion 12, and any method may be used.

In the tooth part direct winding system for directly winding the tooth part 12, the coil end parts 6, 7 of the winding 8 can be made small. Actually, the height of the coil end portions 6 and 7 of the hermetic compressor of the present invention is about half that of the conventional inserter winding system, and the surface area of the winding 8 is correspondingly smaller.

In the hermetic compressor according to the first embodiment of the present invention, the amount of the refrigerant having a large relative dielectric constant dissolved in the refrigerating machine oil is small, and the height of the coil end portion is reduced. Since the inserter winding method is smaller than that of the inserter winding method, that is, the surface area of the motor section can be reduced, an effect of providing a hermetic compressor with reduced leakage current generated through refrigeration oil attached to the motor section can be obtained. Also, since the height of the coil ends 6 and 7 becomes smaller,
The coil length of the winding 8 is short, that is, the electric resistance is small, and an efficient motor unit 2 is obtained.

FIG. 3 is a characteristic diagram showing the result of an investigation on the relationship between superheat and leakage current of refrigeration oil when refrigerant / refrigeration oil is mixed. Table 1 shows the contents of each curve shown in FIG.
Shown in

[Table 1] Note that the tooth portion direct winding method of A2 and B2 relates to the first embodiment of the present invention.
B shows the inserter winding method of the reference example, and C shows the conventional example.

As shown by curve B2 in FIG. 3, the leakage current of the refrigerating machine oil in the hermetic compressor of the first embodiment of the present invention with respect to superheat is represented by curve
Leakage current of a refrigeration cycle using FC22 + (alkylbenzene oil + mineral oil) can be suppressed to the value or less, and high reliability can be obtained. Curve B1 is a reference example showing the characteristics when the winding method is the conventional inserter winding method, and the effect of the present invention shown in curve B2 on reducing the leakage current is clear.

As described above, when the leakage current is reduced by the present invention, when the hermetic compressor of the first embodiment is driven by an inverter, the carrier frequency of the inverter drive circuit can be increased. It is possible to further improve the efficiency of the motor unit.

Further, even if the refrigerant is overfilled when the refrigeration / air-conditioning system is installed, as shown in FIG. 3, during the abnormal operation of the superheat of the refrigerating machine oil of 10 deg or less due to the overfilling. The use of an alkylbenzene-based oil with low mutual solubility with HFC410A to reduce the dissolution rate of the refrigerant in the refrigerating machine oil, and the refrigerating machine oil by using an electric motor in which the teeth are wound directly on the teeth of the stator core The value of the leakage current is reduced by the conventional chlorine-containing refrigerant H
The leakage current of the refrigerating machine oil of the refrigeration cycle of CFC22 + (alkylbenzene-based oil + mineral oil) can be suppressed to a value equal to or less than the value of the leakage current at the time of superheat of 10 deg, and the adverse effects on the surrounding electric and electronic devices can be suppressed to a minimum.

Further, HFC32 single substance or H
When an HFC mixture having a higher HFC32 content than FC410A is used, the relative dielectric constant of HFC32 is HFC4.
Since it is larger than that of 10A, the leakage current in the refrigeration cycle of HFC32 + alkylbenzene oil is
Although it is larger than when 410A + alkylbenzene oil is used, the fact that the coil end portion is made smaller by directly winding the teeth portion of the stator core and the coil end portion is made smaller, taking into account the fact that the surface area is suppressed, is taken into consideration. As shown, it can be suppressed to a practical level. This makes it possible to provide a highly reliable hermetic compressor and a refrigerant circulation system that employ HFC32 as the refrigerant.

Embodiment 2 of the Invention FIG. 4 is a longitudinal sectional view showing a hermetic compressor according to Embodiment 2 of the present invention. In the figure, reference numeral 15 denotes an insulator, which is formed by resin molding so as to enclose the teeth 12 of the stator core 10 and / or the coil ends 6, 7 of the windings 8, or It is formed by resin molding so as to surround the entire winding 8. Reference numeral 33 denotes a cylindrical holding member that integrally holds the motor unit 2 and the compressor unit 3, and reference numeral 34 denotes an elastic support member such as a coil spring that elastically supports the holding member 33 in the closed casing 1. Reference numeral 31 denotes a suction pipe, which has a known function of absorbing a shift caused by swinging of the holding member 33 with respect to the closed container 1, but is not shown. Other reference numerals are the same as or correspond to those of the first embodiment, and the description is omitted.

The insulating material to be molded with the resin is:
Although various known resin mold insulating materials can be used, as a mold resin material that can be particularly preferably used in terms of chemical stability with a refrigerant or refrigerating machine oil, and thermal stability, for example, polyethylene terephthalate,
Examples include polyethylene naphthalate, polyphenylene sulfide, and liquid crystal polymers. These resin materials may be used alone or in combination of two or more.

According to the second embodiment configured as described above, even if the refrigerating machine oil adheres to the teeth portion 12 and the coil end portions 6 and 7, the insulating property is improved by resin molding. The value of the leakage current can be further reduced, and a highly reliable hermetic compressor can be provided. Further, when the hermetic compressor 51 is driven by an inverter by reducing the leakage current, the carrier frequency of the circuit can be increased, so that the efficiency of the motor section can be improved.

The motor unit 2 and the compressor unit 3 are housed in a holding member 33, and the holding member 33 is
, And a gap is provided between the electric motor unit 2 and the sealed container 1 which is an outer shell of the compressor.
The motor unit 2 is no longer in direct contact with the closed container 1,
The contact area can be reduced to a small area of only the elastic support member 34, and the leakage current due to the contact can be reduced. Therefore, a highly reliable hermetic compressor with a smaller leakage current value than in the first embodiment can be realized. The elastic support member 34 may be made of a metal material used as a normal spring material. However, any material having high insulating properties, such as a small conductive metal or resin material, can be used as long as it can maintain strength. Leakage current through the elastic support member 34 can be further reduced.

Embodiment 3 of the Invention In the second embodiment of the present invention, resin molding is performed so as to enclose the teeth 12 of the stator core 10 and the coil ends 6 and 7 of the winding 8 or to enclose the entire winding 8. The motor unit 2 and the compressor unit 3 are housed in a holding member 33, and the holding member 33 is held in the closed container 1 via an elastic support member 34, and the motor unit 2 and the closed container 1 serving as a compressor shell are held. A gap is provided between them, but the effect of reducing the leakage current can be expected with respect to the conventional technology even when either one of the resin molding and the formation of the gap is adopted.

Embodiment 4 of the Invention In any of the first to third embodiments of the present invention, a known liquid injection circuit (not shown) for injecting a liquid refrigerant from a refrigerant circulation system is connected to the cylinder chamber 24 of the compressor unit 3. Can be.

In the fourth embodiment of the present invention, an alkylbenzene-based oil or the like that is incompatible or weakly compatible with the refrigerant is used as the refrigerating machine oil. The discharge gas temperature can be reduced without increasing the generated leakage current, and a highly reliable hermetic compressor can be realized.

Embodiment 5 of the Invention In the first to fourth embodiments, the high pressure shell system in which the pressure in the closed container is equal to the discharge pressure has been described, but the pressure in the closed container is equal to the suction pressure. Similar effects can be expected in the same low-pressure shell system. Further, in each case, the case where the compressor section is a rolling piston type rotary compressor has been described as an example. However, the present invention is not limited to this, and similar effects can be expected in other types of compressors such as a scroll compressor. In addition, in refrigerating machine oil,
A known additive such as an extreme pressure additive may be blended. Further, the case where the present invention is used for a refrigeration / air-conditioning apparatus has been described, but it is a matter of course that the present invention is not limited to this.

[0044]

As described above, according to the present invention,
A stator winding wound directly around the teeth of the stator core via an insulating material is provided, and an HFC-based refrigerant is used as a refrigerant, and the refrigerant does not have mutual solubility as a refrigerating machine oil. Alternatively, by using a weakly compatible refrigerating machine oil, a refrigerant having a large relative dielectric constant is hardly contained in the refrigerating machine oil, and the surface area of the motor unit is reduced. And a hermetic compressor with reduced leakage current.

In addition, as the insulating material is constituted by a resin molding material provided so as to surround the teeth portion,
Leakage current generated through the refrigerating machine oil can be reduced.

Further, since the stator winding is formed by resin molding, the leakage current generated through the refrigerating machine oil can be further reduced.

Further, since the motor section and the compressor section are configured to support the closed container with a gap therebetween through an elastic supporting member, the leakage current can be further reduced.

Further, since the compressor section is provided with the liquid injection circuit, the discharge gas temperature can be lowered without increasing the leakage current, and a highly reliable hermetic compressor can be provided. Can be provided.

By using at least one synthetic resin selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, and liquid crystal polymer as the insulating material, the chemical stability to the refrigerant and the refrigerating machine oil is high, A highly reliable hermetic compressor can be obtained.

As a refrigerant, HFC32 or HF is used.
By using the mixture containing C32, it is possible to obtain a practical and highly reliable hermetic compressor in which the leakage current is suppressed.

As the refrigerating machine oil, alkylbenzene oil, polyalpha-olefin oil, naphthenic mineral oil,
By using a single substance or a mixture of paraffinic mineral oil, refrigerant having a large relative dielectric constant is hardly contained in the refrigerating machine oil, so that an effect of reducing the current leaking through the refrigerating machine oil attached to the electric motor unit can be obtained. Can be

[Brief description of the drawings]

FIG. 1 is a vertical sectional view of a hermetic compressor showing a first embodiment of the present invention.

FIG. 2 is a plan view of the electric motor unit used in the first embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between superheat of refrigeration oil and leakage current when refrigerant / refrigeration oil is mixed in Embodiment 1 of the present invention.

FIG. 4 is a longitudinal sectional view of a hermetic compressor according to Embodiment 2 of the present invention.

FIG. 5 is a refrigerant circuit diagram showing an example of a conventional refrigerant circulation system.

FIG. 6 is a longitudinal sectional view of a conventional compressor.

FIG. 7 is a plan view of a conventional motor unit.

FIG. 8 is a characteristic diagram showing a relationship between superheat of a refrigerating machine oil and leakage current when a conventional refrigerant and refrigerating machine oil are mixed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Closed container 2 Electric motor part 3 Compressor part 6 Coil end 7 Coil end 8 Winding 10 Stator iron core 12 Teeth part 15 Insulator 33 Holding member 34 Elastic support member 41 Refrigerator oil 51 Hermetic compressor

Continued on the front page (72) Inventor Tatsuya Sugita 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Within Mitsubishi Electric Corporation (72) Inventor Mamoru Chiyo No. 2-3-2, Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric F term in the company (reference) 3H003 AA05 AB04 AC03 AD03 BE10 CD07 CF06

Claims (8)

[Claims] 1. A motor unit having a stator core forming a teeth unit, a compressor unit driven by the motor unit to compress refrigerant, and a refrigerating machine oil for lubricating the compressor unit are accommodated in a closed container. The compressor comprises a stator winding wound directly around the teeth via an insulating material, uses an HFC-based refrigerant as the refrigerant, and has mutual solubility with the refrigerant. A hermetic compressor characterized by using refrigerating machine oil having no or weak compatibility. 2. The hermetic compressor according to claim 1, wherein the insulating material is a resin molding material provided so as to surround the teeth portion. 3. The hermetic compressor according to claim 1, wherein the stator winding is formed by resin molding. 4. The electric motor unit and the compressor unit are supported by a closed container via a resilient support member with a gap therebetween. Hermetic compressor 5. The hermetic compressor according to claim 1, wherein the compressor section includes a liquid injection circuit. 6. The insulating material according to claim 1, wherein at least one synthetic resin selected from the group consisting of polyethylene terephthalate, polyethylene naphthalate, polyphenylene sulfide, and a liquid crystal polymer is used. The hermetic compressor according to any one of the above. 7. HFC32 or HFC3 as a refrigerant
The hermetic compressor according to any one of claims 1 to 6, wherein a mixture containing 2 is used. 8. Refrigerating machine oils such as alkylbenzene oils, polyalpha-olefin oils, naphthenic mineral oils,
8. The hermetic compressor according to claim 1, wherein a single substance or a mixture of paraffinic mineral oil and paraffinic mineral oil are used.