JPH10103270A - Hermetic compressor and refrigerator which uses it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable stable operation for a long time even if HFC refrigerant is used by using esters lubricating oil as refrigerator oil and using a polyester film covered with carbodiimide as a plastic insulation film. SOLUTION: Refrigerator oil containing esters oil composed of polyhydric alcohol such as pentane erythritol and fatty acid having the number of carbons of 6 to 10 as basic oil is used. Polyester (polyethylene terephthalate) insulation films 22 covered with carbodiimide are provided between an iron core 4A of a stator 5 and a main coil 4-1 and between the iron core 4A and an auxiliary coil 4-2. Moreover, the same polyester insulation film 23 is provided between the main coil 4-1 and the auxiliary coil 4-2. A carbodiimide component which enters HFC refrigerant due to the elution and sampling from these polyester insulation films 22, 23 contributes to the prevention of the deterioration of esters lubricating oil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hermetic compressor and a refrigeration system using the same, and more particularly, to 1,1,1,2-tetrafluoroethane (hereinafter referred to as R) as a refrigerant.
134a) alone or a mixed refrigerant of R134a, difluoromethane (hereinafter R-32) and pentafluoroethane (hereinafter R-125), R-32 and R-1
The present invention relates to an HFC-based refrigerant such as a refrigerant mixed with H.25, a hermetic electric compressor using a refrigerating machine oil compatible with the refrigerant, and a refrigeration apparatus using the same.

[0002]

2. Description of the Related Art Compressors for refrigerators, vending machines and showcases have conventionally used a large amount of dichlorodifluoromethane (hereinafter referred to as R12) as a refrigerant. This R12
Due to its high ozone depletion potential, it is subject to Freon regulations because of its problem of destroying this ozone layer when it is released into the atmosphere and reaches the ozone layer above the earth. This destruction of the ozone layer is caused by chlorine groups (Cl) in the refrigerant. Therefore, refrigerants containing no chlorine group, for example, R32, R125, R134a, or a mixture thereof are considered as substitute refrigerants, and R134a or the like as a substitute refrigerant for R12 is being studied for refrigerators (for example, See Japanese Patent Application Laid-Open No. 1-271491).

In addition, chlorodifluoromenter (R22) is conventionally used as a refrigerant in air conditioners and the like. However, HFC-based refrigerants have also attracted attention from the viewpoint of the environmental problem of destruction of the ozone layer.

[0004]

However, the above-mentioned HFC-based refrigerants such as R134a have poor compatibility with currently used refrigerating machine oils such as mineral oils and alkylbenzene oils, and deteriorate the return of oil to the compressor. In addition, there is a problem ranging from suction of the separated refrigerant at the time of start-up of the bed to poor lubrication of the compressor.

[0005] For this reason, the present inventors have proposed that H such as R134a
Ester oil was studied as a refrigerating machine oil compatible with FC refrigerant. However, when this ester-based oil is used in a compressor, the temperature tends to rise due to friction and wear of the sliding members inside the compressor, and the ester oil is hydrolyzed by the heat or decomposed by the action of iron oxide or the like. As a result, fatty acids and metal soaps are produced, causing the sliding members to corrode due to the fatty acids and the like, and a sludge component being generated due to abrasion to clog capillary tubes and the like. The oligomers are extracted from organic materials such as plastic insulating film interposed between the iron core of the stator and the magnet wires (main coil and sub-coil) and are adversely affected by hydrolysis, etc. There was a problem that the durability was impaired.

[0006] The first object of the present invention is to use R13 as a refrigerant.
Even if an HFC-based refrigerant such as 4a is used and an ester-based oil compatible with this refrigerant is used, carboxylic acid is generated by thermal decomposition of the sliding member due to frictional heat or hydrolysis of the ester-based oil, and It suppresses the generation of sludge accompanying this, there is no occurrence of corrosion of sliding members or clogging of capillary tubes etc. due to sludge, and there is no problem such as adverse effects on organic materials such as plastic insulating films of electric elements of compressors, To provide a high-performance hermetic compressor excellent in durability and capable of operating stably for a long period of time, and a second object of the present invention is to provide a refrigeration apparatus using the hermetic compressor. That is.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted studies to use an HFC-based refrigerant as a refrigerant and to use an ester-based oil as a refrigerating machine oil compatible with the HFC-based refrigerant in a compressor. As a result, it becomes clear that the ester-based oil that lubricates the sliding member by the frictional heat of the sliding member of the compressor is hydrolyzed, and the resulting fatty acid corrodes the sliding member. Due to the limited combination of the polyester insulating film coated with carbodiimide, the carbodiimide is eluted into the HFC-based refrigerant, or is extracted and acts as a stabilizer. The inventors have found that thermal decomposition and hydrolysis are suppressed, and deterioration of the plastic insulating film is also suppressed, and the present invention has been completed.

That is, as a result of an endurance test, in the case of a rotary compressor, the sliding members, such as vanes and rollers, are severely worn, the total acid value of the ester oil increases, and pits are generated on the roller surface. It was observed that corrosive wear occurred.
The cause is that the ester oil is hydrolyzed by the frictional heat of the sliding member to generate carboxylic acid, which corrodes the iron-based material or reacts with the iron-based material to form metal soap or sludge. I could guess.

That is, according to the first aspect of the present invention, an electric element having a rotating shaft on the upper side in a closed container and a compression element driven by the rotating shaft of the electric element are housed on the lower side, and the air is sucked. A hermetic compressor in which an HFC-based refrigerant or a refrigerant mainly composed of an HFC-based refrigerant is compressed by the compression element and discharged into the hermetic container, and is discharged out of the hermetic container. Is a cylinder, a roller that rotates in the cylinder by an eccentric portion of the rotation shaft, and a vane that contacts the roller and separates the inside of the cylinder,
A high-speed tool comprising an upper bearing portion and a lower bearing portion for closing the opening of the cylinder, using an ester-based lubricating oil as a refrigerating machine oil, and applying a composite material of aluminum and carbon or a surface hardening treatment as the vane. Using a steel vane, a polyester film coated with carbodiimide as a plastic insulating film interposed between the iron core of the stator of the electric element and the main coil and the sub coil, and between the main coil and the sub coil. It is a hermetic compressor characterized by the following.

[0010] The invention of claim 2 of the present invention relates to claim 1 of the present invention.
The hermetic compressor according to claim 1, wherein the vane is a vane made of high-speed tool steel surface-treated with chromium nitride.

According to a third aspect of the present invention, in the hermetic compressor according to the first or second aspect, the insulating film is a polyester film on which a carbodiimide resin is laminated.

According to a fourth aspect of the present invention, there is provided a condenser for condensing and liquefying the refrigerant according to the first aspect, a capillary tube for adjusting the pressure of the refrigerant, an evaporator for evaporating the liquefied refrigerant,
A refrigerating apparatus including an accumulator and a hermetic compressor that compresses the evaporated refrigerant and discharges the refrigerant to a condenser, wherein the hermetic compressor according to claim 1 is used as the hermetic compressor. Is a refrigeration apparatus.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The ester oil used as a base oil in the present invention is not particularly limited. Specifically, for example, polyhydric alcohols such as pentaerythritol (PET), trimethylolpropane (TMP) and neopentyl glycol (NPG) and fatty acids having 6 to 10 carbon atoms, preferably fatty acids having 7 to 9 carbon atoms, Preferably 7 to 9 carbon atoms
Ester-based oil comprising a side chain fatty acid having an average molecular weight of 512 and a viscosity (cSt) (40 ° C.) of 5
1.8 polyol ester oil (α56, manufactured by Japan Energy Co., Ltd.), average molecular weight 668, viscosity (cSt) (4
0 ° C.) 64.2 polyol ester oil (α68, manufactured by Japan Energy Co., Ltd.).

It is preferable to add a phenolic antioxidant as an additive to the ester oil in order to prevent oxidative deterioration during long-term storage.
%, More preferably 0.05 to 0.3% by weight. As antioxidants, 2,6-di-t-butyl-paracresol, 2,6-di-t-butyl-phenol,
2,4,6-tri-t-butyl-phenol and the like can be used.

It is preferable to add a benzotriazole-based copper deactivator to the ester-based oil, if necessary, in an amount of 1 to 100 ppm, more preferably 5 to 100 ppm.
５０50 ppm. As the benzotriazole-based copper deactivator, for example, specifically, 5-methyl-1H-benzotriazole, 1-dioctylaminomethylbenzotriazole and the like can be used.

The present invention will be described below with reference to FIGS. FIG. 1 shows a hermetic compressor a of the present invention for compressing and discharging an evaporated HFC-based refrigerant to a condenser, a condenser b for condensing and liquefying the refrigerant, a capillary tube c for reducing the pressure of the refrigerant, and a liquefied refrigerant. 1 shows a refrigeration cycle of a refrigeration apparatus of the present invention in which an evaporator d and the like for evaporating water are sequentially connected by a refrigerant pipe.

FIG. 2 is a longitudinal sectional view of an example of the hermetic compressor of the present invention. FIG. 3 is a cross-sectional view of the hermetic compressor of the present invention shown in FIG. FIG. 4 is a sectional view taken along line AA of the hermetic compressor of the present invention shown in FIG. 2 and 3, reference numeral 1 denotes a closed container, in which an electric element 2
However, the rotary compression elements 3 driven by the electric elements are stored on the lower side, respectively. The electric element 2 is a winding 4 (main coil 4-1 and sub coil 4-2) insulated with an organic material.
And a stator 5 having an iron core 4A and a rotor 6 provided inside the stator. The rotary compression element 3 includes a cylinder 7 and an eccentric 9
A roller 10 that rotates along the inner wall of the roller, a vane 12 that is pressed against the peripheral surface of the roller and is pressed by a spring 11 to partition the cylinder 7 into a suction side and a discharge side.
It comprises an upper bearing 13 and a lower bearing 14 that seal the opening of the cylinder 7 and support the rotating shaft 8.

FIG. 4 is an enlarged view of a portion B of the stator 5 having the winding 4 and the iron core 4A.
And the main coil 4-1 and between the iron core 4A and the sub coil 4-2.
And a polyester (polyethylene terephthalate) insulating film 22 coated with carbodiimide, and a plastic insulating film 23 between the main coil 4-1 and the sub coil 4-2. .

The method for producing the polyester insulating film coated with carbodiimide is not particularly limited. Specifically, for example, when a liquid carbodiimide is used, a carbodiimide resin such as a spray coating method, an immersion method, a roll coating method, and a brushing method. When the resin film is used, a method of dry laminating the same resin film, a method of extruding the same resin film or a method of co-extruding the same resin film, and a method of laminating the same resin film using an adhesive can be used. When coating the polyester insulating film with carbodiimide, one side of the polyester insulating film may be coated, both sides of the polyester insulating film may be coated, and the surfaces coated on one side of the polyester insulating film may be uncoated. Or any one of them.

By using the polyester insulating film coated with the carbodiimide in this manner, the deterioration of the insulating film can be suppressed, and the carbodiimide contained in the HFC-based refrigerant by being eluted and extracted from the insulating film. The components contribute to preventing deterioration of the ester-based lubricating oil.

The upper bearing 13 is provided with a discharge hole 15 communicating with the discharge side of the cylinder 7. A discharge valve 16 for opening and closing the discharge hole 15 and a discharge muffler 17 are attached to the upper bearing 13 so as to cover the discharge valve.

The roller 10 is formed of an iron-based material such as cast iron, and the vane 12 is formed of a composite material of aluminum and carbon, or a high-speed steel surface-hardened with chromium nitride or the like.

An HFC-based refrigerant, for example, a refrigerant mixture of three kinds of R134a, R32 and R125 or a refrigerant mixture of two kinds of R32 and R125 is sealed in the bottom of the closed vessel 1, and is compatible with this refrigerant. Certain refrigerator oils such as pentaerythritol (PET), trimethylolpropane (TMP) or neopentyl glycol (NPG)
An oil 18 containing a polyol ester oil composed of a polyhydric alcohol such as a fatty acid and a fatty acid as a base oil is enclosed.

The oil 18 lubricates a sliding surface between the roller 10 and the vane 12 which are sliding members of the rotary compression element 3.

The refrigerant that flows into the cylinder 7 of the rotary compression element 3 and is compressed by the cooperation of the roller 10 and the vane 12 is, for example, R407C [R134a] which is compatible with the ester-based oil 18 as described above. And a mixed refrigerant of R32 and R125], R410A [a mixed refrigerant of R32 and R125], and the like.

Reference numeral 19 denotes a suction pipe which is attached to the closed vessel 1 and guides the refrigerant to the suction side of the cylinder 7, and 20 is attached to the upper wall of the closed vessel 1 and is compressed by the rotary compression element 3 via the electric element 2. This is a discharge pipe for discharging the refrigerant to the outside of the closed container 1.

In the hermetic compressor using the oil 18, the refrigerant flowing from the suction pipe 19 to the suction side in the cylinder 7 is compressed by the cooperation of the roller 10 and the vane 12 and discharged through the discharge hole 15. The valve 16 is opened to discharge into the discharge muffler 17. The refrigerant in the discharge muffler is discharged from the discharge pipe 20 to the outside of the closed container 1 via the electric element 2. The oil 18 is supplied to the roller 1 of the rotary compression element 3.
The lubrication is carried out by being supplied to the sliding surface of a sliding member such as 0 or vane 12. Further, the refrigerant compressed in the cylinder 7 is prevented from leaking to the low pressure side.

[0028]

EXAMPLES The present invention will be described below in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples. (Example 1) Vane 12 formed of a carbon composite material in which aluminum was infiltrated [composition: C: 55, Al: 36, Si: 6, other (Mg, etc.): 3 (all by weight%)] The following tests were conducted using the refrigerating apparatus (bench stand test apparatus) of the present invention in which a hermetic rotary compressor (exclusion volume: 7.65 cc), a condenser, an expansion valve, and an evaporator were connected by piping. A durability test was performed under the conditions, and the degree of wear of the sliding portions of the cylinder 7, the rotating shaft 8, the roller 10, the vane 12, the upper bearing 13, and the lower bearing 14, the amount of sludge in a discharge valve (not shown) provided in the discharge pipe 20, Hue of oil (measurement method: according to ASTM method described in JIS K2580), amount of oil returned to the bottom of sealed container 1, polyester insulating film 2 used for electric element 2 of compressor
Deterioration of 2, 23 etc. was measured. No sludge was generated on the sliding portion of the vane 12. No deterioration occurred in the polyester insulating film. Table 1 shows the test results.

A in the degree of abrasion in Table 1 indicates that the wear is small and the condition is the same as that of a new article. B indicates that the abrasion is normal, and AB indicates the middle abrasion between A and B. And C shows a state of wear that is so severe that it is not practical. A in the sludge column in Table 1 indicates a state in which the amount of generated sludge is small, B indicates that the amount of generated sludge is normal, and AB indicates the amount of sludge intermediate between A and B. The state of the amount of generation is shown, and C indicates a state in which the amount of generation of sludge is too large to be practical.

Pressure condition: High pressure 23.0 kg / cm ² · G, low pressure: 1.0 kg / cm ² · G Operating frequency: 100 HZ, Operating time: 200 hr, Refrigerant: R134a Case upper temperature: 110 to 120 ° C. Polyester insulating film : Calcoat E film (a film in which a carbodiimide resin is coated on the surface of a PET film; manufactured by Nisshinbo Co., Ltd.) Roller: Cast iron Composition (wt%): C (total carbon): 3.2 to 3.6 Si: 2.2 to 2.9, Mn: 0.6 to 1.0, P: 0.18max, S: 0.08max Ni: 0.1 to 0.2, Cr: 0.20max MO: 0.07 to 0.2, Ti: 0.25max The balance is iron

Lubricating oil composition (oil): A polyetherester-based oil (SUNICE E-68NTI, manufactured by Nippon Sun Oil Co., Ltd.) is used as a base oil.
Oil to which 0.3% by weight of 2,6-di-t-butyl-paracresol was added (the hue before use was L0.5) (a charged amount: 230 cc).

Comparative Example 1 Table 1 shows the results of a test performed in the same manner as in Example 1 except that a PET film having no carbodiimide resin coated on the surface was used.

[0033]

[Table 1]

From Table 1, it can be seen that in Example 1, there was no abrasion of each sliding portion, the amount of sludge was small, the hue of the oil did not change from the time of preparation, and the amount of returned oil was large. On the other hand, in Comparative Example 1, wear of each sliding portion was slightly observed, the amount of sludge exceeded the practical level, and sludge was generated in the sliding portion of the vane 12. The hue of the oil was worse than at the time of preparation.

3.1 g of the Calcoat E film used in Example 1 and 3.1 g of the PET film used in Comparative Example 1 were put in 50 ml of the ester-based lubricating oil used in Example 1 (initial water content: 100 ppm). Table 2 shows the results of measuring the presence or absence of precipitates and the amount of oligomer extracted from each film after the treatment for 10 days.

[0036]

[Table 2]

From Table 2, it can be seen that in the case of a PET film (Calcoat E film) coated with a carbodiimide resin on the surface, there is no precipitate and the amount of oligomer extracted is small. On the other hand, the PET film has a precipitate and a large amount of oligomer is extracted.

The Calcoat E film used in Example 1 and 3.1 g of the PET film used in Comparative Example 1 were put in 50 ml of the ester lubricating oil used in Example 1 (initial water content: 50 ppm and 100 ppm), and 175
Table 3 shows the results obtained by measuring the total acid value of each lubricating oil after treatment at 10 ° C for 10 days.

[0039]

[Table 3]

From Table 3, it can be seen that a PET film (Calcoat E film) coated with a carbodiimide resin on the surface has an effect of suppressing deterioration of the ester-based lubricating oil. On the other hand, in the case of the PET film, the total acid value was higher than in the case of using only the ester-based lubricating oil.

[0041]

As described above, the hermetic compressor of the present invention and the refrigerating apparatus using the same are configured as described above, so that even when an ester-based refrigerating machine oil is used as the refrigerating machine oil and an HFC-based refrigerant is used, the vane is cooled. No sludge is generated on the sliding part, the polyester insulating film used for the electric element of the hermetic compressor and the ester-based refrigerating machine oil used do not deteriorate,
There is no problem that the generated sludge is deposited on the capillary tube in the refrigeration circuit and clogged, and the operation can be stably performed for a long time.

[Brief description of the drawings]

FIG. 1 is a refrigeration circuit diagram of an example of a refrigeration apparatus of the present invention.

FIG. 2 is a longitudinal sectional view of an example of the hermetic compressor of the present invention.

FIG. 3 is a cross-sectional view of the hermetic compressor of the present invention shown in FIG. 2;

FIG. 4 is a sectional view of the hermetic compressor of FIG. 2 taken along line AA.

[Description of Signs] 1 Closed container 2 Electric element 3 Rotary compression element 4 Winding 4A Iron core 4-1 Main coil 4-2 Sub coil 5 Stator 6 Rotor 7 Cylinder 8 Rotation axis 9 Eccentric part 10 Roller 11 Spring 12 Vane 13 Upper bearing 14 Lower bearing 15 Discharge hole 16 Discharge valve 17 Discharge muffler 18 Oil 19 Suction pipe 20 Discharge pipe 21 Hollow hole 22, 23 Polyester insulating film

Claims (4)

[Claims] An electric element having a rotating shaft on the upper side in a closed container and a compression element driven by the rotating shaft of the electric element are housed on a lower side, and the sucked HFC-based refrigerant or the HFC-based refrigerant is mainly contained therein. The compressed compressor is compressed by the compression element and discharged into the closed container, and is discharged outside the closed container, wherein the compression element is a cylinder and an eccentricity of the rotating shaft. A roller that rotates inside the cylinder by a portion, a vane that contacts the roller and separates the inside of the cylinder, and an upper bearing and a lower bearing that seal the opening of the cylinder. And a vane made of a composite material of aluminum and carbon or a high-speed tool steel subjected to surface hardening treatment as the vane. A hermetic compressor characterized in that a polyester film coated with carbodiimide is used as a plastic insulating film interposed between a main coil and a sub coil, and between a main coil and a sub coil. 2. The hermetic compressor according to claim 1, wherein the vane is a high-speed tool steel vane surface-treated with chromium nitride. 3. The hermetic compressor according to claim 1, wherein the insulating film is a polyester film on which a carbodiimide resin is laminated. 4. A condenser for condensing and liquefying the refrigerant according to claim 1, a capillary tube for adjusting the pressure of the refrigerant, an evaporator for evaporating the liquefied refrigerant, an accumulator, and compressing the vaporized refrigerant to a condenser. A refrigerating apparatus provided with a hermetic compressor for discharging and the like, wherein the hermetic compressor according to claim 1 is used as the hermetic compressor.