JP3208334B2 - Hermetic compressor and refrigeration apparatus using the same - Google Patents

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 oil and alkylbenzene oil, so that the return of oil to the compressor is deteriorated. 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.

For this reason, the present inventors have proposed that H
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 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 Suppressing the generation of sludge accompanying this, there is no occurrence of corrosion of sliding members or clogging of capillary tubes etc. due to sludge, 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 oil which lubricates the sliding member is hydrolyzed by the frictional heat of the sliding member of the compressor, and the sliding member is corroded by the generated fatty acid. If a limited combination of the coated specific plastic insulating film is used, since the carbodiimide acts as a stabilizer, the thermal decomposition and hydrolysis of the ester-based oil due to the frictional heat generated in the sliding member are suppressed, and the plastic insulating The inventors have found that the deterioration of the film can be suppressed, and have completed the present invention.

That is, as a result of the durability test, it was observed that the sliding member was severely worn, the total acid value of the ester oil was increased, and 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.

According to the first aspect of the present invention, an electric motor having a rotating shaft on the lower side in a closed container and a reciprocating compression unit driven by the rotating shaft of the electric motor are housed on the upper side and sucked. A hermetic compressor in which an HFC-based refrigerant or a refrigerant mainly composed of an HFC-based refrigerant is compressed by the reciprocating compression section and discharged to the outside of the closed container, using an ester-based lubricating oil as a refrigerating machine oil, A hermetic type wherein a polyester film coated with carbodiimide is used as a plastic insulating film interposed between the iron core of the stator of the electric motor and the main coil and the sub coil, and between the main coil and the sub coil. It is a compressor.

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

According to a third 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.

[0012]

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 this ester-based oil in order to prevent oxidative deterioration during long-term storage.
It is 1.0% by weight, more preferably 0.05 to 0.3% by weight. As an antioxidant, 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, and 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 an example of a refrigeration cycle of a refrigeration apparatus of the present invention in which an evaporator d for evaporating water is 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 sectional view of the hermetic compressor of the present invention shown in FIG. In FIG. 2, reference numeral 1 denotes a closed container, in which a motor unit 2 disposed on a lower side;
The reciprocating compression unit 3 disposed on the upper side is housed. The reciprocating compression unit 3 and the electric motor unit 2 are elastically attached to the inner wall of the closed casing 1. The motor unit 2 has a winding (consisting of a main coil 18 and a sub coil 19 described later) 4 inside an iron core 5.
A stator 5 wound around A, a rotor 6 disposed inside the stator, and a rotating shaft 8 inserted into the center of the rotor and supported by bearings 7. .

The reciprocating compression section 3 includes a cylinder 9, a piston 11 which reciprocates in the cylinder by being fitted to a crankpin 10 of a rotating shaft 8, a valve seat 12 provided on an end face of the cylinder 9, and a And a cylinder head 13 that is attached to the cylinder 9 through the cylinder head 13. Valve seat 12
A discharge valve (not shown) for opening and closing a discharge port is attached to the cylinder head 13 side.

An HFC-based refrigerant, for example,
R134a, R32 and R125 mixed refrigerant (R4
07C) or a refrigerant mixture of two kinds of R32 and R125 (R410A) is sucked, and pentaerythritol (PET), trimethylolpropane (TMP), or neopentyl glycol (NPG), which are refrigerating machine oils compatible with this refrigerant. Oil based on a polyol ester oil consisting of a polyhydric alcohol such as a fatty acid and a fatty acid 1
4 are enclosed.

In the hermetic compressor (reciprocating compressor) of the present invention using the refrigerating machine oil (oil) 14, the HFC-based refrigerant flowing into the cylinder 9 by the reciprocating sliding of the piston 11 It is compressed and discharged to an external refrigeration cycle by opening a discharge valve (not shown).

The oil 14 put in the bottom of the sealed container 1 fills the inside of the lubricating oil cup through the hole 16 of the lubricating oil cup 15, and has a hollow lubricating oil passage 17 in the center of the lubricating oil cup 15. The rotary shaft 8 has a rotary shaft 8, and the high-speed rotation of the rotary shaft 8 causes a vacuum phenomenon caused by a vortex generated at the upper open end, so that the oil 14 is sucked up and circulated to each sliding portion such as the piston 11 / cylinder 9 and the rotary shaft 8 / bearing 7. Self-lubrication to lubricate.

FIG. 3 is an enlarged view of a portion B of the stator 5 having the winding 4 and the iron core 5A.
A carbodiimide-coated polyester (polyethylene terephthalate) insulating film 20 is interposed between the main coil 18 and the iron core 5A and the sub coil 19, and also between the main coil 18 and the sub coil 19. The plastic insulating film 20 is interposed.

The method for producing the polyester insulating film coated with the 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.

[0024]

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) Hermetic compressor (exclusion volume 7.65) of the present invention
cc), a durability test was performed under the following test conditions using a refrigeration apparatus (bench stand test apparatus) of the present invention in which a condenser, an expansion valve, and an evaporator were connected by pipes, and a bearing 7, a rotating shaft 8, a cylinder 9, The degree of wear of the sliding portions of the crank pin 10 and the piston 11, the amount of sludge at a discharge valve (not shown), the hue of oil (measured by the ASTM method described in JIS K2580), the amount of oil returned to the bottom of the sealed container 1, the compressor The deterioration of the polyester insulating film 20 used for the motor unit 2 was measured. No deterioration occurred in the polyester insulating film. Table 1 shows the test results.

A in the degree of wear in Table 1 indicates that the wear is small and the condition is the same as that of a new product, B indicates that the wear is normal, and AB indicates that the wear is intermediate 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 conditions: 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 (P
A film in which a carbodiimide resin is coated on the surface of an ET film. (Manufactured by Nisshinbo)

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 is added (the hue before use is L0.5)
(Prepared 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.

[0029]

[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 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, abrasion of each sliding portion was slightly observed, the amount of sludge exceeded the practical level, the hue of the oil was worse than at the time of preparation, and the PET film was deteriorated.

[0031] 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 into 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.

[0032]

[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.

[0035]

[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.

[0037]

As described above, the hermetic compressor of the present invention and the refrigeration apparatus using the same are constructed as described above, so that the hermetic compressor can be used even if an ester-based refrigeration oil is used as the refrigeration oil and an HFC-based refrigerant is used. The polyester insulating film used for the electric element of the compressor and the ester refrigeration oil used did not deteriorate, the wear of the sliding parts was suppressed, and there was no problem that sludge was deposited on the capillary tubes in the refrigeration circuit and clogged, It can be operated stably 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 sectional view of the hermetic compressor of FIG. 2 taken along line AA.

[Description of Signs] 1 Closed container 2 Motor unit 3 Reciprocating compression unit 4 Winding 5A Iron core 5 Stator 6 Rotor 7 Bearing 8 Rotating shaft 9 Cylinder 10 Crank pin 11 Piston 12 Valve seat 13 Cylinder head 14 Oil 15 Lubricating oil Cup 16 hole 17 lubricating oil passage 18 main coil 19 sub coil 20 polyester insulating film

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 39/00 F04B 39/00 106 F25B 1/00 395

Claims (3)

(57) [Claims] 1. A motor unit having a rotating shaft on the lower side in a closed container and a reciprocating compression unit driven by the rotating shaft of the motor unit on the upper side. A hermetic compressor in which a main refrigerant is compressed by the reciprocating compression section and discharged out of the hermetic container, wherein an ester-based lubricating oil is used as a refrigerating machine oil, and an iron of a stator of the electric motor section is used. A hermetic compressor characterized by using a polyester film coated with carbodiimide as a plastic insulating film interposed between a core and 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 said insulating film is a polyester film laminated with a carbodiimide resin. 3. 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.