JP2011157408A - Reciprocating compressor and refrigerator using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve abrasion resistance of a reciprocating compressor using isobutane as a coolant, and to achieve high efficiency of a refrigerator using the reciprocating compressor. <P>SOLUTION: A refrigerator oil comprises a primary refrigerator oil containing a monoester oil or a polyol ester oil and an additional polyol ester oil added to the primary refrigerator oil. The refrigerator oil is sealed in the reciprocating compressor which uses isobutane as a coolant. The amount of the additional polyol ester oil composition is 1-30 wt%. Preferably, dynamic viscosity of the refrigerator oil at 40°C is 10 mm<SP>2</SP>/s or less, while dynamic viscosity of the additional polyol ester oil at 40°C is 130 mm<SP>2</SP>/s or greater. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a reciprocating compressor and a refrigerator using the same.

  Global environmental measures in the field of refrigerating and air-conditioning equipment include substitution of CFC (Chlorofluorocarbons) and HCFC (Hydrochlorofluorocarbons), which have been used as refrigerants and heat insulating materials as ozone depleting substances, as well as higher efficiency and refrigerants as a countermeasure against global warming Substitutes for HFC (Hydrofluorocarbons) used in Japan, and these have been actively promoted.

  As alternatives to CFCs and HCFCs, which are ozone-depleting substances, the selection of refrigerants and heat insulating materials and equipment development were promoted with the main objective of not destroying the ozone layer, low toxicity and low flammability, and ensuring efficiency. . As a result, in the heat insulating material of the refrigerator, the foaming agent is replaced in the order of CFC11, HCFC141b, and cyclopentane, and now it is shifted to the combined use with the vacuum heat insulating material.

  As the refrigerant, CFC12C and HFC134a (GWP (Global Warming Potential) = 1430) were substituted in the order of refrigerators and car air conditioners, and HCFC22 and R410A (GWP = 2088) were substituted in the order of room air conditioners and packaged air conditioners.

However, at the Conference of the Parties to the 3rd Framework Convention on Climate Change, which was held in Kyoto in 1997 (COP3), for HFC emissions has become subject to regulation are terms of CO ₂ as a greenhouse gas, reduction of HFC is advanced It became a thing.

  In view of this, in the refrigerator for home use, it was judged that the amount of refrigerant enclosed was small and a flammable refrigerant could be used for manufacturing, and HFC134a was replaced with flammable R600a (isobutane: GWP = 3). Furthermore, due to the growing public opinion, attention is now focused on the HFC134a for car air conditioners, the room air conditioner and the R410A for packaged air conditioners. Moreover, in commercial refrigerators, the amount of R600a enclosed is large, and HFC134a is still used because of the fear of flammability.

  On the other hand, refrigeration oil is used in a hermetic electric compressor and plays a role of lubrication, sealing, cooling and the like of a sliding portion thereof.

  In the refrigerator, it is essential to improve the performance of the compressor in order to reduce the annual electricity consumption. Therefore, a reduction in the viscosity of the refrigerating machine oil has been studied for the purpose of reducing the mechanical loss of the compressor.

  However, since the oil film in the sliding portion becomes thin due to the low viscosity of the refrigerating machine oil, there is a problem that the refrigerant leakage loss increases.

  Patent Document 1 and Patent Document 2 disclose refrigeration air-conditioning equipment using refrigeration oil that mixes different oil viscosities.

JP 58-93796 A Special table 2009-540170 gazette

  An object of the present invention is to improve the wear resistance of a reciprocating compressor that uses isobutane as a refrigerant and to realize high efficiency of a refrigerator using the reciprocating compressor.

  The reciprocating compressor according to the present invention is a reciprocating compressor that uses isobutane as a refrigerant and encloses a refrigerating machine oil containing a monoester oil or polyol ester oil and an added polyol ester oil added thereto. The composition of the added polyol ester oil is 1 to 30% by weight.

  According to the present invention, it is possible to reduce the viscosity of refrigerating machine oil, and it is possible to obtain a compressor that achieves both improvement in compressor performance and wear resistance without using harmful phosphorus-based extreme pressure agents.

  In addition, according to the present invention, it is possible to reduce the viscosity of refrigerating machine oil, and obtain an environment-friendly refrigerator that can achieve both improvement in refrigerator performance and long-term reliability without using an environmentally harmful phosphorus-based extreme pressure agent. be able to.

It is a schematic longitudinal cross-sectional view which shows the refrigerator of an Example. It is the schematic which shows the refrigerating cycle of a refrigerator. It is sectional drawing which shows the reciprocating type hermetic compressor for refrigerators of an Example.

  Hereinafter, a reciprocating compressor according to an embodiment of the present invention and a refrigerator using the same will be described.

The reciprocating compressor uses isobutane (R600a) as a refrigerant, a monoester oil represented by the following chemical formula (1) (wherein R ¹ represents an alkyl group having 5 to 9 carbon atoms, and R ² represents carbon. Represents an alkyl group having 8 to 10 carbon atoms), a polyol ester oil represented by the following chemical formula (2) (wherein R ³ represents an alkyl group having 5 to 9 carbon atoms) and the following chemical formula (3). A refrigerating machine main agent containing at least one kind of base oil selected from the group consisting of polyol ester oils represented by the formula (wherein R ³ represents an alkyl group having 5 to 9 carbon atoms), and the following chemical formula (4) A refrigerating machine oil containing an added polyol ester oil represented by the formula (wherein R ⁴ represents an alkyl group having 7 to 9 carbon atoms). The composition of the added polyol ester oil is 1 to 30% by weight.

前記レシプロ式圧縮機においては、冷凍機油主剤の４０℃における動粘度が１０ｍｍ^２／ｓ以下であり、添加ポリオールエステル油の４０℃における動粘度が１３０ｍｍ^２／ｓ以上であることが望ましい。

In the reciprocating compressor, it is desirable that the kinematic viscosity at 40 ° C. of the refrigerating machine main oil is 10 mm ² / s or less, and the kinematic viscosity at 40 ° C. of the added polyol ester oil is 130 mm ² / s or more.

  The reciprocating compressor includes a sliding portion formed of an iron-based material, and a contact surface pressure at the sliding portion is 10 MPa or more.

  In the reciprocating compressor, the added polyol ester oil has an adsorption capacity for iron-based materials of 1.6 times or more higher than that of the refrigerating machine oil main agent. Furthermore, the adsorption capacity of the added polyol ester oil to the iron-based material is preferably 2 times or more, and more preferably 4 times or more.

  The refrigerator uses the reciprocating compressor.

  Hereinafter, it demonstrates in detail using an Example.

  The examples disclose a compressor using isobutane and a refrigerator using the compressor.

  The refrigerant of the example is isobutane, and the refrigerating machine oil includes a base oil that has a low adsorption capacity for iron-based materials (a base oil that is difficult to adsorb) and a base oil that has a high adsorption capacity for iron-based materials (a base oil that easily absorbs). including.

  The base oil having a low adsorption capacity is a compound having an ester group in the molecular structure, and examples thereof include monoester oil and polyol ester oil.

  Monoester oil is obtained by a condensation reaction of a monohydric alcohol and a monohydric fatty acid.

  Examples of monohydric alcohols include n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, isoheptanol, isooctanol, isononanol, isodecanol, isoundecanol, 2-ethylhexanol, 1-ethyl hexanol, Examples include methylheptanol, 3,5,5-trimethylhexanol, 2,6-dimethyl-4-heptanol, and these are used alone or in combination of two or more.

  Monovalent fatty acids include n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, There are isooctanoic acid, 3,5,5-trimethylhexanoic acid and the like, which are used alone or in combination of two or more.

  The polyol ester oil is obtained by a condensation reaction between a polyhydric alcohol and a monovalent fatty acid.

  As the polyol ester oil, a hindered type having excellent thermal stability is preferable, and as the polyhydric alcohol, neopentyl glycol, trimethylolpropane, pentaerythritol and the like are preferable.

  Monovalent fatty acids include n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, There are isooctanoic acid, 3,5,5-trimethylhexanoic acid and the like, which are used alone or in combination of two or more.

  The base oil having a high adsorption capacity for the iron-based material is a polyol ester oil containing a large amount of ester groups in the molecular structure, and a divalent fatty acid complex ester oil using a dicarboxylic acid such as hexanedioic acid (adipic acid) is preferable. A hindered type synthesized from a polyhydric alcohol and a monovalent fatty acid is more preferable.

  An example of a polyhydric alcohol is dipentaerythritol.

  Monovalent fatty acids include n-pentanoic acid, n-hexanoic acid, n-heptanoic acid, n-octanoic acid, 2-methylbutanoic acid, 2-methylpentanoic acid, 2-methylhexanoic acid, 2-ethylhexanoic acid, There are isooctanoic acid, 3,5,5-trimethylhexanoic acid and the like, which are used alone or in combination of two or more.

Although the viscosity grade of the refrigerating machine oil used for the refrigerator of an Example changes with kinds of compressor, in the reciprocating compressor, the range whose viscosity in 40 degreeC is 2.5-15 mm < ² > / s is preferable.

  In the present invention, a lubricity improver, an antioxidant, an acid scavenger, an antifoaming agent, a metal deactivator and the like may be added to the above refrigerating machine oil. In particular, monoester oils and polyol ester oils are deteriorated due to hydrolysis in the presence of moisture, so that an antioxidant and an acid scavenger are indispensable.

  As the antioxidant, DBPC (2,6-di-t-butyl-p-cresol) which is a phenol type is preferable.

  As the acid scavenger, an aliphatic epoxy compound is generally used as a compound having an epoxy ring. In addition, the carbodiimide-based compound has extremely high reactivity with fatty acids, and captures hydrogen ions dissociated from fatty acids, so that the effect of suppressing the hydrolysis reaction of polyol ester oil is very high. Examples of the carbodiimide compound include bis (2,6-isopropylphenyl) carbodiimide. The compounding amount of the acid scavenger is preferably 0.05 to 1.0% by weight with respect to the refrigerating machine oil.

(Refrigerating machine oil component)
In order to increase the efficiency of the reciprocating refrigerant compressor, it is effective to reduce the viscosity of the refrigerating machine oil that reduces the viscous resistance. However, when the viscosity of the oil is reduced, the oil film strength at the compressor sliding portion is lowered, and thus wear proceeds. For this reason, the adsorptivity with respect to the sliding part of a refrigerator oil component becomes an important parameter.

  Most of the sliding parts are made of an iron-based material, and iron oxide is formed on the surface thereof.

  The adsorption capacity of the refrigerating machine oil to the iron-based material in this specification is considered to be substantially the adsorption capacity of the refrigerating machine oil to the iron oxide.

Based on this concept, in this example, the adsorption capacity of refrigerating machine oil was evaluated using powder (specific surface area 1.57 m ² / g) of Fe ₃ O ₄ (iron trioxide) having an average particle diameter of 1 μm. went.

  The concentration of the refrigerating machine oil component diluted in the solvent before and after adsorption was quantified by nuclear magnetic resonance analysis (NMR), and the amount adsorbed on the iron oxide powder was calculated. Hexane was used as the solvent, and each refrigerating machine oil component was adjusted to 0.3 mol-ppm. After 3 g of iron oxide powder was collected in a 20 ml screw tube, 10 g of a solution of a refrigerator oil component was added, dispersed in an ultrasonic cleaner for 30 minutes, and allowed to stand for 48 hours for 1H-NMR analysis of the supernatant.

  Here, mol-ppm is ppm (parts per million) on a molar basis. In other words, it is a percentage calculated using the number of moles of the solution (mixture of solvent and solute) as the denominator and the number of moles of the solute as the numerator.

  The base oil used as the refrigerator oil component is shown below. Here, the 40 ° C. viscosity is a viscosity at 40 ° C.

(A) Monoester oil (condensate of octanol and 2-ethylhexanoic acid): 40 ° C. viscosity 2.8 mm ² / s
(B) Monoester oil (condensate of 2-ethylhexanol and 2-ethylhexanoic acid): 40 ° C. viscosity 2.7 mm ² / s
(C) Hindered type polyol ester oil (POE) (neopentyl glycol-based 2-ethylhexanoic acid ester oil): 40 ° C., viscosity 7.5 mm ² / s
(D) Hindered type polyol ester oil (POE) (neopentyl glycol-based 3,5,5-trimethylhexanoic ester oil): 40 ° C. viscosity 13.1 mm ² / s
(E) Hindered type polyol ester oil (POE) (pentaerythritol-based 3,5,5-trimethylhexanoic acid ester oil): 40 ° C. viscosity 44.8 mm ² / s
(F) Hindered type polyol ester oil (POE) (dipentaerythritol-based 2-ethylhexanoic acid ester oil): 40 ° C. viscosity 150 mm ² / s
(G) Hindered type polyol ester oil (POE) (dipentaerythritol-based 3,5,5-trimethylhexanoic acid ester oil): 40 ° C. viscosity 417 mm ² / s
(H) Hindered type polyol ester oil (POE) (dipentaerythritol-based branched chain fatty acid ester oil): 40 ° C. viscosity 217 mm ² / s
(I) Polyvinyl ether oil (PVE): 40 ° C. viscosity 65 mm ² / s
(J) Polyalkylene glycol oil (PAG) (polypropylene glycol dimethyl ether): 40 ° C. viscosity 22.36 mm ² / s
(K) Naphthenic mineral oil: 40 ° C. viscosity 4.85 mm ² / s
(L) Poly α-olefin oil: 40 ° C. viscosity 30.3 mm ² / s
(M) Soft alkylbenzene oil: 40 ° C. viscosity 4.24 mm ² / s
(N) Paraffinic mineral oil: 40 ° C. viscosity: 7.8 mm ² / s
(O) Naphthenic mineral oil: 40 ° C. viscosity 145 mm ² / s
Table 1 shows the results of measuring the amount of the compound adsorbed on the iron oxide powder.

各化合物により酸化鉄粉に対する吸着量（吸着能力）が異なっており、有極性化合物の方が鉄系材料に吸着し易いことがわかる。

The adsorption amount (adsorption ability) with respect to the iron oxide powder differs depending on each compound, and it is understood that the polar compound is more easily adsorbed to the iron-based material.

  It can be seen that even in polar compounds, the compounds (F), (G) and (H) having a large number of ester groups in the molecular structure have a particularly large amount of adsorption. That is, (F), (G), and (H) have an adsorption capacity for iron-based materials (iron oxide) of 1 compared to other refrigeration oil components (A) to (E) and (I) to (O). It can be seen that it is 6 times higher.

  From this, it is considered that the base oils 6 to 8 (refrigerating machine oil components (F), (G) and (H)) easily form an oil film in the compressor sliding portion.

  This is considered to be due to the following reason.

  The oxygen in the double bond (C = O) of carbon and oxygen contained in the ester group tends to be negatively charged. On the other hand, iron contained in iron oxide tends to be positively charged (easily becomes a cation). For this reason, it is considered that an attractive force is generated between the iron oxide iron and the double-bonded oxygen due to Coulomb force, and is easily adsorbed.

  From these results, base oils 6 to 8 (refrigerator oil components (F), (G) and (H)) were decided to be used as additive polyol ester oils in the present invention. Base oils 1 to 5 and 9 to 15 (refrigerator oil components (A) to (E) and (I) to (O)) were used as the refrigerator oil main agent in the present invention.

(Examples 1-3)
(Comparative Examples 1-4)
An example of a specific refrigerator of the present embodiment is shown in FIG.

  In the refrigerator box 1, there are a refrigerator compartment 2 and a freezer compartment 3, both of which are partitioned by a wall. The refrigeration cycle for cooling the inside of the refrigerator includes a compressor 4, a condenser 5, a dehydrator 6, a capillary tube, an evaporator 7, and a blower fan 8.

  The cold air cooled by the evaporator 7 is sent to the freezer compartment 3 by the blower fan 8, and then sent to the refrigerator compartment 2 through the damper 9 as shown by the arrow in the figure. 7 circulates in the flow path cooled.

  Next, the refrigeration cycle of the refrigerator shown in FIG. 1 will be described. A basic refrigeration cycle configuration diagram of the refrigerator is shown in FIG.

  The compressor 4 compresses the low-temperature and low-pressure refrigerant gas, discharges the high-temperature and high-pressure refrigerant gas, and sends it to the condenser 5. The refrigerant gas sent to the condenser 5 becomes a high-temperature and high-pressure refrigerant liquid while releasing its heat into the air, and is sent to the capillary tube 10 via the dehydrator 6. The high-temperature and high-pressure refrigerant liquid that passes through the capillary tube 10 becomes low-temperature and low-pressure wet steam due to the throttling effect, and is sent to the evaporator 7. The refrigerant that has entered the evaporator 7 absorbs heat from the surroundings and evaporates, and the air generated thereby is sent into the box by the blower fan 8. The low-temperature and low-pressure refrigerant gas exiting the evaporator 7 is sucked into the compressor 4 and a similar refrigeration cycle is repeated.

  Refrigerant equal volume compressors are mainly used as refrigerant compressors for refrigerators.

  FIG. 3 shows a schematic structure of a reciprocating refrigerant compressor as an example of the compression means.

  In this figure, the reciprocating type refrigerant compressor houses a compression part and a motor 12 in a sealed container 11 and stores refrigerating machine oil 13 in an oil reservoir part at the bottom of the sealed container (lower part of the motor 12). A slidable piston 15 is fitted to the inner diameter of the cylinder 14 constituting the compression portion, and the piston 15 reciprocates in the cylinder 14 by the eccentric rotation of the crankshaft 16 of the rotating shaft that transmits the rotational force of the motor 12. Thus, the refrigerant gas is sucked, compressed and discharged.

  The compressed refrigerant gas is discharged to the external refrigeration cycle through the discharge port 17. The refrigerating machine oil 13 stored in the oil reservoir provided in the lower part of the motor 12 is supplied to the lubrication of each sliding part of the compressor through the oil hole 18 provided in the crankshaft 16.

  In Examples 1 to 3, base oils 6 to 8 (refrigerating machine oil components (of refrigerating machine oil components (A) to (O)) shown in Table 1 having high adsorption ability to iron-based materials. A combination of F) to (H)) as one component is used.

  A refrigerant containing the above refrigerating machine oil was sealed in a reciprocating compressor, installed in the refrigerator shown in FIG. 1, and a long-life test was performed in a constant temperature room (40 ° C.) under high pressure and high load for 2160 hours.

  Table 2 shows combinations of refrigerating machine oils.

本表において、冷凍機油成分（Ａ）〜（Ｏ）は、表１に示すものである。

In this table, the refrigerator oil components (A) to (O) are shown in Table 1.

That is, (A) 80% by weight and high adsorption capacity (H) 20% by weight were mixed, and the kinematic viscosity at 40 ° C. was 5.2 mm ² / s, Example 1 (C) 97% by weight and adsorption Example 2 in which 3% by weight of (H) having a high capacity was mixed and the kinematic viscosity at 40 ° C. was set to 8.1 mm ² / s, and (C) 97% by weight and 3% by weight of (F) having a high adsorption capacity And Example 3 was used in which the kinematic viscosity at 40 ° C. was 8.0 mm ² / s.

  As Comparative Examples 1 and 2, a combination of compounds having low adsorption ability was used.

Specifically, Comparative Example 1 in which (K) 80% by weight and adsorbing capacity are equal and kinematic viscosity (O) 20% by weight is mixed, and the kinematic viscosity at 40 ° C. is 8.5 mm ² / s. And (C) 80% by weight and (E) 20% by weight, which is lower in adsorption capacity than Examples 1 to 3, are mixed, and the kinematic viscosity at 40 ° C. is 10.2 mm ² / s. It was.

  Moreover, it is the same combination of the components as Example 2, and the comparative example 3 which made the density | concentration of the component 2 (H) 0.5 weight% and the comparative example 4 which made the density | concentration of the component 2 (H) 40 weight% Tests were also conducted.

  None of the refrigerating machine oils of the above Examples and Comparative Examples contains a phosphorus extreme pressure additive.

  In improving the reliability of the refrigerator, it is important to suppress the frictional wear of the compressor. Therefore, the evaluation of the refrigerator is focused on the wear state of the reciprocating compressor, and the connecting rod outside, which is a processed part of the iron-based material of the sliding part that has a sliding surface pressure of 10 MPa or more and is placed in the most severe conditions The wear amount of the sphere and the sphere in the piston was measured.

  Moreover, about the refrigerator using the refrigerating machine oil of Examples 1-3, power consumption amount measurement was performed by JISC9801 (the characteristic and test method of a household electric refrigerator and an electric freezer), and the annual power consumption was computed.

  Here, the annual power consumption of the refrigerator using the refrigerating machine oil of Comparative Example 2 is displayed as 100%.

  The target values in these tests are that the wear amount of the inner spherical surface of the piston is 10 μm or less, and the annual power consumption is less than 100%.

  The results of Examples 1 to 3 and Comparative Examples 1 to 4 are shown in Table 2.

  From Table 2, the refrigerator using the refrigerating machine oil of Examples 1 to 3 can greatly reduce the wear amount of the piston inner sphere compared with the reciprocating compressor of the refrigerator using the refrigerating machine oil of Comparative Examples 1 and 2. And high reliability is obtained. Furthermore, the refrigerator using the refrigerating machine oil of Examples 1 to 3 has a lower kinematic viscosity of the refrigerating machine oil as compared with Comparative Example 2, thereby reducing the mechanical loss and reducing the annual power consumption.

  In Comparative Example 1, a reduction in annual power consumption is recognized by reducing the kinematic viscosity of the refrigerating machine oil. However, even if low viscosity oil and high viscosity oil are mixed, it is a combination with low adsorption capacity for ferrous materials, so lubricity is not maintained, and between the connecting rod-piston where sliding is the most severe within a few hours from the start of the test. Seizure occurred and the test was interrupted. Therefore, the amount of wear could not be measured.

  In Comparative Example 2 in which a polyol ester oil having a low kinematic viscosity and a polyol ester oil having a high kinematic viscosity are mixed, since a compound having a low adsorption capacity is blended, the wear of the sliding portion of the compressor increases. The target wear amount of 10 μm or less cannot be achieved.

  From this result, when using refrigeration oil that combines low viscosity oil and high viscosity oil with low adsorption capacity for iron-based materials, both reducing the amount of wear and improving efficiency of refrigerators and reciprocating compressors. You can't do that.

  Comparative Example 3 is a combination of the refrigerating machine oils whose effects were confirmed in Example 2, with the compounding amount of the compound (H) having a high adsorption capacity in the iron-based material being 0.5% by weight. It can be seen that the annual power consumption of the refrigerator can be reduced, but the wear cannot be suppressed. This is presumably because a sufficient amount of refrigerating machine oil is not adsorbed on the sliding portion of the compressor.

  Furthermore, in the refrigerator combined with 40% by weight of the compound (H) having a high adsorption capacity in the same combination of refrigerating machine oils, the wear can be greatly suppressed, but the annual power consumption cannot be reduced. This is presumably because a sufficient amount of refrigeration oil is adsorbed on the sliding portion of the compressor, but the kinematic viscosity increases and the efficiency of the compressor decreases.

  As described above, in order to obtain a refrigerator in which the wear of the reciprocating compressor is greatly suppressed and the annual power consumption is small, a refrigerator oil containing 1 to 30% by weight of a compound having a high adsorption capacity for iron-based materials is used. It can be seen that it is desirable to use it. Further, it is more desirable to use a refrigerating machine oil blended with 2 to 25% by weight of a compound having a high adsorption capacity for iron-based materials.

  If the compounding amount of the compound having a high adsorption capacity in the iron-based material is less than 1% by weight, sufficient wear resistance of the compressor sliding portion cannot be obtained, and if it exceeds 30% by weight, it is difficult to reduce the annual power consumption. Thus, the characteristics cannot be compatible.

  ADVANTAGE OF THE INVENTION According to this invention, while reducing the viscosity (kinematic viscosity) of refrigerating machine oil, the oil film in a sliding surface can be maintained and abrasion of a sliding surface can be suppressed.

  According to the present invention, the mineral oil alone maintains the lubricity of the sliding surface, the ecotoxicity at the time of environmental leakage is great, and the Basel Convention regulated substance (Domestic law: Law on the regulation of import / export of specified hazardous waste, etc.) The wear resistance can be improved without using an extreme pressure additive typified by TCP: tricresyl phosphate.

  The present invention is applicable to a reciprocating refrigerant compressor and a refrigerator.

  1: box, 2: cold room, 3: freezer, 4: compressor, 5: condenser, 6: dehydrator, 7: evaporator, 8: blower fan, 9: damper, 10: capillary tube, 11 : Closed container, 12: motor, 13: refrigerator oil, 14: cylinder, 15: piston, 16: crankshaft, 17: discharge port, 18: oil hole.

Claims (5)

A monoester oil represented by the following chemical formula (1) using isobutane as a refrigerant (wherein R ¹ represents an alkyl group having 5 to 9 carbon atoms, and R ² represents an alkyl group having 8 to 10 carbon atoms). ), A polyol ester oil represented by the following chemical formula (2) (wherein R ³ represents an alkyl group having 5 to 9 carbon atoms) and a polyol ester oil represented by the following chemical formula (3) (wherein R ³ represents an alkyl group having 5 to 9 carbon atoms.) A refrigerating machine main agent containing at least one kind of base oil selected from the group consisting of: and an added polyol ester oil represented by the following chemical formula (4) (formula Wherein R ⁴ represents an alkyl group having 7 to 9 carbon atoms.) And a reciprocating compressor containing a refrigerating machine oil containing 1 to 30% by weight of the additive polyol ester oil. Features a reciprocating compressor.

The reciprocating type according to claim 1, wherein the refrigerating machine oil main component has a kinematic viscosity at 40 ° C of 10 mm ² / s or less, and the added polyol ester oil has a kinematic viscosity at 40 ° C of 130 mm ² / s or more. Compressor.   3. The reciprocating compressor according to claim 1, wherein the reciprocating compressor includes a sliding portion formed of an iron-based material, and a contact surface pressure at the sliding portion is 10 MPa or more.   The reciprocating compressor according to any one of claims 1 to 3, wherein the added polyol ester oil has an adsorption capacity for an iron-based material that is 1.6 times or more higher than that of the refrigerating machine oil main component.   A refrigerator using the reciprocating compressor according to any one of claims 1 to 4.

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