JP2018087528A - Hermetic type compressor and freezing cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hermetic type compressor having preferable oil return performance while giving stable lubricity to slide members over a long period of time using the coolant containing 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-terafluoropropene, and 20% by mass or more of 1,1,1,2-terafluoroethane, and polyol ester lube oil as refrigeration oil.SOLUTION: A hermetic type compressor comprises: a compressor part for compressing coolant stored in a closed vessel; an electric motor part for driving the compressor part; and refrigeration oil. The coolant contains: 20% by mass or more of difluoromethane; 20% by mass or more of pentafluoroethane; 20% by mass or more of 2,3,3,3-terafluoropropene; and 20% by mass or more of 1,1,1,2-terafluoroethane. The refrigeration oil uses polyol ester lube oil having a low-temperature side two-layer separation temperature with the coolant of -42°C±5°C.SELECTED DRAWING: Figure 1

Description

  Embodiments described herein relate generally to a hermetic compressor and a refrigeration cycle apparatus.

  A refrigeration cycle apparatus such as a refrigerator or a refrigerator incorporates a hermetic compressor that compresses a refrigerant. Conventionally, HFC (hydrofluorocarbon) refrigerants such as HFC-134a and HFC-125, which have zero ozone layer depletion potential (ODP), are used as this refrigerant.

  However, while these HFC refrigerants have zero ODP, they have the disadvantage of a relatively high global warming potential (GWP), and use of refrigerants with low GWP is desired.

  Therefore, Patent Document 1 discloses a low GWP refrigerant containing a predetermined amount of difluoromethane, pentafluoroethane, 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane. (R448A, R449A, etc.) are disclosed.

  By the way, the hermetic compressor incorporates refrigerating machine oil for imparting lubricity to the sliding member in the hermetic container and suppressing or preventing wear of the sliding member. The refrigerating machine oil is desired to have compatibility with R448A and R449A as refrigerants.

  Patent Document 1 discloses a compressor using a low GWP refrigerant containing difluoromethane, pentafluoroethane, 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane as a refrigerant. A refrigerating machine oil containing at least one oxygenated oil having a carbon / oxygen molar ratio of 2.5 or more and 5.8 or less as a base oil is disclosed.

International Publication No. 2016/056392

  Patent Document 1 discloses an electrical insulating property in the use of a low GWP refrigerant containing difluoromethane, pentafluoroethane, 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane as a refrigerant. The invention of a refrigeration oil improved in that the need remains to provide stable lubricity over a long period of time to a sliding member of a compressor in combination with the refrigerant.

  The present invention uses a low GWP refrigerant containing difluoromethane, pentafluoroethane, 2,3,3,3-tetrafluoropropene and 1,1,1,2-tetrafluoroethane as a refrigerant, and a polyol ester-based lubricating oil Is used as a refrigerating machine oil to provide a sliding compressor with a stable lubricity over a long period of time and a good oil return property.

  According to the embodiment, a hermetic compression provided with a hermetic container, a compressor part that is stored in the hermetic container and compresses a refrigerant, an electric motor part that drives the compressor part, and refrigeration oil is provided in the refrigeration cycle. A machine is provided. The refrigerant is 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass or more of 1,1,1,2 -Including tetrafluoroethane. As the refrigerating machine oil, a polyol ester-based lubricating oil having a low temperature side two-layer separation temperature with the refrigerant of −42 ° C. ± 5 ° C. is used.

It is a lineblock diagram showing the refrigerating cycle of the refrigerating cycle device provided with the closed type compressor concerning a 1st embodiment. It is a top view which shows the 1st cylinder chamber of FIG. It is a graph which shows the compatibility of R448A refrigerant | coolant of Example 1, and refrigerating machine oil, and the behavior of two-layer separation. It is a graph which shows the relationship between the PV value between the roller and blade in 2nd Embodiment, and the surface roughness of a roller. It is a graph which shows the relationship between the rotation speed of a roller at the time of the operation | movement of evaporation temperature -40 degreeC of the refrigerating cycle in 2nd Embodiment, and the condensation temperature 50 degreeC, and PV value between a roller and a blade. It is a figure which shows the endurance test result of Examples 11 and 12 and Comparative Example 11.

  Hereinafter, various embodiments will be described in detail.

<First Embodiment>
The hermetic compressor according to the first embodiment is provided in a refrigeration cycle. The compressor includes a sealed container, a compressor unit that compresses a specific refrigerant stored in the sealed container, an electric motor unit that is stored in the sealed container and drives the compressor unit, and the sealed container Specific refrigeration oil built in the

  The refrigerant is 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass or more of 1,1,1,2- A mixed refrigerant having a composition containing tetrafluoroethane, for example, R448A or R449A.

  As the refrigerating machine oil, a polyol ester-based lubricating oil having a low temperature side two-layer separation temperature with the refrigerant of −42 ° C. ± 5 ° C. is selected. Here, the two-layer separation means that the single layer of the refrigerant and the refrigerating machine oil is not completely separated but separated into the refrigerant rich layer and the refrigerating machine oil rich layer. The polyol ester-based lubricating oil is produced, for example, by synthesis of a polyhydric alcohol and a branched fatty acid.

  Examples of polyhydric alcohols include trimethylolethane, trimethylolpropane, pentaerythritol or dipentaerythritol. Among the polyhydric alcohols, pentaerythritol is preferable from the viewpoint of compatibility with the refrigerant and stability.

  Examples of branched fatty acids include 2-methylhexanoic acid, 2-methylpentanoic acid, 2-ethylhexanoic acid or 3,5,5-trimethylhexanoic acid, and can be used alone or in two or more forms. The branched fatty acid is preferably 2-ethylhexanoic acid and 3,5,5-trimethylhexanoic acid.

  The refrigerating machine oil may contain additives such as an antioxidant and an acid scavenger.

  Examples of antioxidants include dibutyl cresol. Antioxidant can be mix | blended in the ratio of 0.05-1.0 mass% with respect to refrigerating machine oil. When the amount of the antioxidant is less than 0.05% by mass, the effect becomes poor. On the other hand, when the amount of the antioxidant exceeds 1.0% by mass, the effect is saturated and it is not economical.

  Examples of the acid scavenger include an epoxy compound (for example, a glycidyl ester type epoxy compound or a glycidyl ether type epoxy compound). An acid scavenger can be mix | blended in the ratio of 0.2-1.5 mass% with respect to refrigerating machine oil. When the amount of the acid scavenger is less than 0.2% by mass, the effect becomes poor. On the other hand, if the amount of the acid scavenger exceeds 1.5% by mass, the electrical insulation resistance may be adversely affected.

  According to the first embodiment described above, 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass or more. For example, when the R448A refrigerant or the R449A refrigerant is used, the sliding member is provided with a stable lubricity over a long period of time, which is a mixed refrigerant having a composition containing 1,1,1,2-tetrafluoroethane. In addition, it is possible to provide a hermetic compressor having a good oil return property.

  The R448A refrigerant or R449A refrigerant having the above composition becomes a negative pressure when the evaporation temperature falls below -42 ° C. When the negative pressure is used, if a low-pressure side pipe including the evaporator of the refrigeration cycle apparatus using the refrigerant has a pinhole, a crack, or the like, air may be taken in. The temperature is set to -42 ° C or higher, desirably -40 ° C or higher.

  Also, in the compressor provided in the refrigeration cycle, the higher the two-layer separation temperature is higher than -42 ° C, the worse the oil return property from the evaporator to the compressor part of the compressor, and the lower the oil supply due to the lack of lubricating oil. To do.

  Furthermore, as the two-layer separation temperature is lower than −42 ° C., the kinematic viscosity of the refrigerating machine oil decreases excessively due to the compatibility of the refrigerant with the refrigerating machine oil, and the lubricity decreases.

  For this reason, according to the first embodiment, R448A refrigerant or R449A refrigerant is used, and a polyol ester-based lubricating oil having a low temperature side two-layer separation temperature of −42 ° C. ± 5 ° C. with the refrigerant is used as a refrigerating machine oil. By using it, the deterioration of the oil return property from the evaporator is avoided, and further, the refrigerant is not excessively compatible with the refrigerating machine oil, and the decrease in lubricity due to the penetration of the refrigerant can be suppressed.

  Therefore, even if R448A or R449A having the above composition with zero ozone depletion index (ODR) and reduced global warming potential (GWP) is used as the refrigerant, a highly reliable hermetic compressor can be provided.

  The refrigeration cycle apparatus according to another first embodiment includes a compressor according to the first embodiment, a condenser that is a radiator connected to the compressor, and an expansion device connected to the condenser. And an evaporator that is a heat absorber connected between the expansion device and the compressor.

  Next, the refrigeration cycle apparatus including the compressor according to the first embodiment will be described more specifically with reference to FIGS. 1 and 2.

  FIG. 1 is a configuration diagram illustrating a refrigeration cycle of a refrigeration cycle apparatus R including a hermetic compressor 1.

  The hermetic compressor (hereinafter simply referred to as “compressor”) 1 will be described later. A refrigerant pipe P is connected to the upper end of the compressor 1, and a condenser 2, a gas-liquid separator 3, an expansion valve (expansion device) 4, an evaporator 5 and an accumulator 6 are connected to the refrigerant pipe P. It is provided in order. The refrigerant pipe P is further branched into two from the accumulator 6 and connected to the side portion of the compressor 1, and these constitute the refrigeration cycle of the refrigeration cycle apparatus R.

  The refrigeration cycle apparatus R is provided with an injection circuit K. This injection circuit K divides a part of the liquid refrigerant gas-liquid separated by the gas-liquid separator 3 interposed between the condenser 2 and the expansion valve 4 to the injection pipe Pa, and is provided in the injection pipe Pa. It is for guiding to the compressor 1 through the open / close valve 7 and the fluid control valve 8 as described later.

  The compressor 1 includes an airtight container 10, an electric motor part 11 is accommodated on the upper side of the airtight container 10, and a compressor part 12 is accommodated on the lower side, and the electric motor part 11 and the compressor part 12 have a rotating shaft. 13 are connected. The refrigerating machine oil S is collected at the inner bottom of the sealed container 10 and the remaining internal space is filled with a high-pressure gas refrigerant compressed by the compressor unit 12. As the refrigerant, the R448A refrigerant or the R449A refrigerant having the above-described composition is used. As the refrigerating machine oil, a polyol ester-based lubricating oil having a low temperature side two-layer separation temperature with a refrigerant of −42 ° C. ± 5 ° C. is used.

  A discharge portion 1 a including a hole is provided on the upper surface portion of the sealed container 10, and a refrigerant pipe P communicating with the condenser 2 is connected thereto. The lower peripheral wall of the sealed container 10 is provided with suction portions 1b and 2b made of two holes, and a refrigerant pipe P communicating with the accumulator 6 is connected thereto.

  The motor unit 11 has a rotor (rotor) 15 fitted and fixed to the rotary shaft 13, and an inner peripheral surface of the rotor 15 facing the outer peripheral surface of the rotor 15 through a narrow gap. It is comprised from the stator (stator) 16 fixed by fitting.

  The rotary shaft 13 is formed with two columnar eccentric parts a and b that protrude toward the outer peripheral side. These eccentric portions a and b are provided at positions spaced apart by a predetermined dimension along the axial direction of the rotating shaft 13 and at positions displaced by 180 ° along the rotating direction of the rotating shaft 13.

  The compressor unit 12 includes a main bearing 17, a first cylinder 18 having an inner diameter hole, an intermediate partition plate 20, a second cylinder 22 having an inner diameter hole, and a sub bearing along the axial direction of the rotary shaft 13. 23. The main bearing 17 is fixed to the first cylinder 18 by a fixture, and the auxiliary bearing 23 is fixed to the first cylinder 18 via the second cylinder 22 and the intermediate partition plate 20 by the fixture. The main bearing 17 and the auxiliary bearing 23 pivotally support the rotating shaft 13.

  A first muffler case 25, which is a hollow case surrounding the periphery, is attached to the main bearing 17, and a muffler chamber is formed inside. The first muffler case 25 is provided with a plurality of communication holes c that allow the muffler chamber and the space in the sealed container 10 to communicate with each other. These communication holes c are located above the liquid level of the refrigerating machine oil S collected at the inner bottom of the sealed container 10.

  A second muffler case 26, which is a hollow case surrounding the periphery, is attached to the auxiliary bearing 23, and a muffler chamber is formed inside. The sub bearing 23, the second cylinder 22 and the intermediate partition plate 20 are always immersed in the refrigerating machine oil S reliably. The first cylinder 18 and the first muffler case 25 may be exposed from the refrigerating machine oil S due to the influence of compression conditions and the like.

  The first cylinder 18 is fitted and fixed to the inner peripheral wall of the sealed container 10. The inner diameter hole of the first cylinder 18 is closed at the upper end side by the main bearing 17 and closed at the lower end side by the intermediate partition plate 20 to form a first cylinder chamber 18A.

  The second cylinder 22 is attached to the first cylinder 18 via the intermediate partition plate 20. The inner diameter hole of the second cylinder 22 is closed at the upper end side by the intermediate partition plate 20 and closed at the lower end side by the auxiliary bearing 23 to form a second cylinder chamber 22A.

  A rotating shaft 13 is inserted into the first and second cylinder chambers 18A and 22A, and one eccentric portion a formed on the rotating shaft 13 is located in the first cylinder chamber 18A and formed on the rotating shaft 13. The other eccentric portion b is positioned in the second cylinder chamber 22A.

  A roller 27 is fitted to one eccentric part a, and a roller 28 is fitted to the other eccentric part b. These rollers 27 and 28 roll while a part of the outer peripheral wall abuts against the inner peripheral walls of the first and second cylinder chambers 18A and 22A as the rotary shaft 13 rotates.

  Blades 30 and 31 are provided in the first and second cylinder chambers 18A and 22A, respectively, so as to be able to reciprocate. The front ends of the blades 30 and 31 are urged by an elastic body d such as a spring, and the roller 27 , 28 is in contact with the outer peripheral wall. Further, a part of the outer peripheral wall of the rollers 27 and 28 is in contact with a part of the inner peripheral wall of the first and second cylinder chambers 18A and 22A, and the tips of the blades 30 and 31 are elastically attached to the outer peripheral wall of the rollers 27 and 28 The first and second cylinder chambers 18A and 22A are partitioned into two spaces whose volumes vary with the rolling of the rollers 27 and 28.

  The first cylinder 18 is provided with a suction portion 1b for sucking low-pressure gas refrigerant into the first cylinder chamber 18A. The second cylinder 22 is provided with a suction portion 2b for sucking low-pressure gas refrigerant into the second cylinder chamber 22A.

  The flange portion of the main bearing 17 is provided with a first discharge valve mechanism 33 that is opened and closed by the eccentric motion of the roller 27. By opening the first discharge valve mechanism 33, the first cylinder chamber 18A and the muffler chamber in the first muffler case 25 attached to the main bearing 17 are communicated with each other.

  The flange portion of the auxiliary bearing 23 is provided with a second discharge valve mechanism 34 that is opened and closed by the eccentric motion of the roller 28. By opening the second discharge valve mechanism 34, the second cylinder chamber 22A communicates with the muffler chamber in the second muffler case 26 attached to the sub bearing 23.

  The muffler chamber in the first muffler case 25 attached to the main bearing 17 and the muffler chamber in the second muffler case 26 attached to the sub bearing 23 are the flange portion of the main bearing 17 and the first cylinder 18. And the intermediate partition plate 20, the second cylinder 22, and a discharge guide flow path (not shown) provided in the flange portion of the auxiliary bearing 23.

  On the other hand, the injection pipe Pa constituting the injection circuit K passes through the hole provided in the side portion of the sealed container 10 and is inserted into the sealed container 10 so as to face the intermediate partition plate 20. The intermediate partition plate 20 is provided with a lateral hole 35 from the side portion (outer peripheral surface) toward the center portion, and the distal end portion of the injection pipe Pa is inserted into the lateral hole 35 and closely fitted.

  At the center of the intermediate partition plate 20, there is provided an insertion hole 20a through which the portion between the eccentric parts a and b of the rotating shaft 13 is inserted, and the tip of the horizontal hole 35 does not reach the insertion hole 20a. It ends on the near side. The tip of the injection tube Pa does not reach the tip of the horizontal hole 35, and is dimensioned so as to have a certain gap.

  A first injection port 36a and a second injection port 36b each including a vertical hole are provided in a portion of the horizontal hole 35 between the distal end of the injection tube Pa and the distal end of the horizontal hole 35. These lateral holes 35, the first injection port 36a, and the second injection port 36b constitute an injection mechanism.

  An insertion hole 20a through which a part of the rotary shaft 13 is inserted is provided at the center of the intermediate partition plate 20 and has a ring shape in plan view. Further, a lateral hole 35 is provided from a part of the peripheral wall toward the central axis of the insertion hole 20a. The diameter of the horizontal hole 35 is set within the thickness range of the intermediate partition plate 20. A first injection port 36 a is provided at a position slightly in front of the front end of the horizontal hole 35 so as to communicate with the upper surface of the intermediate partition plate 20 and the horizontal hole 35. A second injection port 36b is provided in communication with the lower surface of the intermediate partition plate 20 and the lateral hole 35.

  The distance La from the central axis O of the intermediate partition plate 20 and the insertion hole 20a to the central axis of the first injection port 36a, and the center of the second injection port 36b from the central axis of the insertion hole 20a of the intermediate partition plate 20 The distances Lb to the axes are the same (La = Lb), and intersect the vertical holes 35 vertically. That is, the first and second injection ports 36a and 36b are provided at the same angular position in the circumferential direction and at the positions where the center axis positions thereof coincide with each other.

  The diameter of the first injection port 36a and the diameter of the second injection port 36b may be the same, but here are different from each other. Here, the diameter of the first injection port 36a is set larger than the diameter of the second injection port 36b.

  In such a configuration, when the electric motor unit 11 is energized, the rotating shaft 13 rotates and the compressor unit 12 is driven, whereby the first and second cylinder chambers 18A and 22A partitioned by the blades 30 and 31 are driven. One of the spaces is made negative and gas refrigerant flows.

  The rollers 27 and 28 provided with a phase difference of 180 ° roll as the rotary shaft 13 rotates, and the gas refrigerant flowing into the first and second cylinder chambers 18A and 22A flows into one space. The volume is compressed by gradually decreasing.

  When compressed to a predetermined pressure, the first discharge valve mechanism 33 is opened and discharged from the first cylinder chamber 18A to the muffler chamber of the first muffler case 25. Further, the second discharge valve mechanism 34 is opened with an interval of 180 °, and discharged from the second cylinder chamber 22A to the muffler chamber of the second muffler case 26.

  Thereafter, the gas refrigerant discharged into the second muffler case 26 is discharged from the second cylinder 22, the intermediate partition plate 20, the first cylinder 18, and the main bearing 17. It is led to a muffler chamber in the first muffler case 25 through a path. And it is guide | induced to the space in the airtight container 10 from the communicating hole c with the gas refrigerant with which this muffler room is filled.

  The high-temperature and high-pressure gas refrigerant (including misted refrigeration oil) filling the sealed container 10 of the compressor 1 flows through the refrigerant pipe P connected to the discharge unit 1a and is led to the condenser 2. Here, the refrigerant containing the mist refrigerating machine oil is condensed and liquefied, led to the gas-liquid separator 3 in a state where the liquid refrigerant and the refrigerating machine oil are mixed, further gas-liquid separated, and once collected. Thereafter, the liquid refrigerant is decompressed by the expansion valve 4 and evaporated by the evaporator 5. Ambient air is cooled by this evaporation, and the refrigeration cycle apparatus R exhibits refrigeration (cooling) capability.

  The refrigerant exiting the evaporator 5 is gas-liquid separated by the accumulator 6, and is guided to the first cylinder chamber 18A and the second cylinder chamber 22A via the first and second suction portions 1b and 2b of the compressor 1. It is compressed. Then, it is compressed again as described above, and circulates in the above-mentioned system path.

  On the other hand, as the compressor 1 is operated, the temperature of the gas refrigerant that is compressed in the first and second cylinder chambers 18A and 22A and fills the sealed container 10 rises and is discharged to the refrigerant pipe P, whereby the refrigerant pipe The temperature of P rises.

  When a temperature sensor (not shown) attached to the refrigerant pipe P detects a predetermined temperature or higher, a detection signal is sent to a control means (not shown). The control means performs control to open the on-off valve 7 of the injection circuit K.

  The gas-liquid separator 3 that collects the refrigerant (including refrigerating machine oil) liquefied by the condenser 2 functions as a liquid receiver, from which a part of the liquid refrigerant is led to the injection pipe Pa. The fluid control valve 8 has a function as a flow rate adjusting valve that adjusts the opening according to the temperature detected by the temperature sensor.

  The liquid refrigerant guided to the injection pipe Pa in the compressor 1 is divided into the first injection port 36a and the second injection port 36b from the distal end portion of the lateral hole 35 of the intermediate partition plate 20.

  The liquid refrigerant is guided from the first injection port 36a to the first cylinder chamber 18A, and is injected into the gas refrigerant in the middle of compression in the first cylinder chamber 18A, thereby cooling the gas refrigerant. Further, the liquid refrigerant is guided from the second injection port 36b to the second cylinder chamber 22A and is injected into the gas refrigerant in the middle of compression in the second cylinder chamber 22A to cool the gas refrigerant.

  FIG. 2 is a plan view of the first cylinder chamber 18A. In this first cylinder chamber 18A, the roller 27 moves from the solid line position to the solid line position via the alternate long and short dash line position, in the counterclockwise direction that is the arrow direction. Eccentric motion continuously.

  In the first cylinder chamber 18A, the position where the roller 27 (the eccentric direction of the eccentric part a) coincides with the direction of the blade 30 is defined as the reference position (0 °), and the roller 27 is rotated 6 ° counterclockwise from the reference position. At the position, the first injection port 36a starts to be opened from the lower end surface of the roller 27, and the liquid refrigerant is injected into the first cylinder chamber 18A.

  The opening of the first injection port 36a is maintained while the rotation angle is increased by the eccentric rotational movement of the roller 27. Therefore, the liquid refrigerant is continuously injected from the first injection port 36a into the first cylinder chamber 18A, and the gas refrigerant compressed in the first cylinder chamber 18A is cooled.

  When the rotational angle position of the roller 27 exceeds 180 ° and reaches 210 °, the lower end surface of the roller 27 starts to close the first injection port 36a. Therefore, the amount of liquid refrigerant injected from the first injection port 36a into the first cylinder chamber 18A is gradually reduced.

  When the rotational angle position of the roller 27 (the eccentric direction of the eccentric part a) reaches 212 °, the first injection port 36a is completely closed by the lower end surface of the roller 27, and the liquid refrigerant to the first cylinder chamber 18A is blocked. The injection stops.

  This state continues until the rotation angle position of the roller 27 exceeds 360 ° and reaches 6 °, and when it reaches 6 °, the first injection port 36a is opened again from the lower end surface of the roller 27 as described above. The above operation is repeated.

  In the second cylinder chamber 22A, the second injection port 36b is opened and closed at a different timing from a position where the roller 28 is provided at a position 180 ° opposite to the roller 27 in the first cylinder chamber 18A. To do.

  Further, since the diameter of the second injection port 36b is smaller than the diameter of the first injection port 36a, the rotation angle range of the roller 28 opened by the second injection port 36b is the roller 27 opened by the first injection port 36a. Is smaller than the rotation angle range (6 ° to 212 °).

  As described above, the diameter of the first injection port 36a and the diameter of the second injection port 36b are set to different diameters.

  Here, the first cylinder 18 provided with the first cylinder chamber 18A is provided at the upper part of the intermediate partition plate 20, and the second cylinder 22 provided with the second cylinder chamber 22A is provided at the lower part of the intermediate partition plate 20. It was. The second cylinder 22 is constantly immersed in the refrigerating machine oil S collected at the bottom of the sealed container 10, but the first cylinder 18 is often exposed from the oil surface of the refrigerating machine oil S due to compression conditions.

  Therefore, the diameter of the first injection port 36a is set larger than the diameter of the second injection port 36b. The amount of liquid refrigerant injected into the first and second cylinder chambers 18A and 22A is proportional to the diameter of the first and second injection ports 36a and 36b. Therefore, the amount of liquid refrigerant injected into the first cylinder chamber 18A is larger than the amount of liquid refrigerant injected into the second cylinder chamber 22A.

  Since the second cylinder 22 is constantly immersed and cooled in the refrigerating machine oil S collected in the inner bottom portion of the sealed container 10, the amount of liquid refrigerant injected into the second cylinder chamber 22A is the first. Even if it is less than the amount of liquid refrigerant injected into one cylinder chamber 18A, it does not fall into an overheated state.

  On the other hand, the first cylinder 18 is located at the upper part of the intermediate partition plate 20, and usually the refrigerating machine oil S is collected up to the flange part of the main bearing 17 attached to the upper part, but depending on the compression conditions. The liquid level of the refrigerating machine oil S is lowered, and the first cylinder 18 is often exposed from the oil level of the refrigerating machine oil S.

  That is, even if the first cylinder chamber 18A and the second cylinder chamber 22A perform the same compression action, the temperature of the first cylinder chamber 18A is more likely to rise than that of the second cylinder chamber 22A. Therefore, by increasing the amount of liquid refrigerant injected into the first cylinder chamber 18A via the first injection port 36a, efficient cooling is achieved and compression performance is improved.

  As described above, the operation of the refrigerating apparatus including the hermetic compressor 1 includes R448A and R449A as refrigerants and a polyol ester-based lubricating oil having a low-temperature two-layer separation temperature of −42 ° C. ± 5 ° C. By using it with the refrigerating machine oil, it is possible to impart a stable lubricity over a long period of time to a sliding member including a roller and a blade, and to achieve a good oil return property.

  Hereinafter, the evaluation of the hermetic compressor according to the first embodiment will be described in detail.

Example 1
20% by weight or more of difluoromethane, 20% by weight or more of pentafluoroethane, 20% by weight or more of 2,3,3,3-tetrafluoropropene and 20% by weight or more of 1,1,1,2-tetrafluoroethane R448A refrigerant having a composition containing

  Also, pentaerythritol, which is a polyhydric alcohol, and 2-methylhexanoic acid and 3,5,5-trimethylhexanoic acid, which are branched fatty acids, were prepared, and a polyol ester oil was synthesized using these as raw materials.

It was 8.9 mm < ² > / s when the kinematic viscosity in 100 degreeC of the obtained polyol ester oil was measured based on Japanese Industrial Standard (JIS) K2283. Moreover, when the acid value of the polyol ester oil was measured according to JIS C2101, it was 0.01 mgKOH / g or less.

To the resulting polyol ester oil, 0.1 mass% of 2,6-di-tert-butyl-p-cresol as an oxidizing agent and 0.5 mass% of a glycidyl ester type epoxy compound as an acid scavenger were added. A refrigerating machine oil was prepared. The refrigerating machine oil does not contain tricresyl phosphate which is widely used as an antiwear agent. When the volume resistivity at 25 ° C. of the obtained refrigerating machine oil was measured according to JIS C2101, it was 3 × 10 ¹² Ω · m.

  Furthermore, the low temperature side two-layer separation temperature of the refrigerating machine oil with the R448A refrigerant was measured in accordance with “Test method for compatibility with refrigerant” prescribed in Appendix D of JIS K2211-2009. It was. FIG. 3 is a graph showing a two-layer separation temperature curve when the amount of the refrigerating machine oil relative to the R448A refrigerant is changed. The higher temperature side of the curve is the compatible region of the R448A refrigerant and the refrigerating machine oil, and the lower temperature side of the curve is the R448A refrigerant. This is a two-layer separation zone for refrigerating machine oil.

  The obtained R448A refrigerant and refrigerator oil were accommodated in a 3HP inverter refrigerator, and the behavior of the refrigerator oil in the cycle was examined. As a result, the oil level of the refrigerating machine oil stored in the compressor oil was not significantly lowered, and the refrigerating machine oil had good oil return properties.

  Further, in the durability test under an overload condition of 1000 hours, the sliding members (rollers and blades) were free from abnormal wear and were good.

(Comparative Example 1)
Pentaerythritol, which is a polyhydric alcohol, and 2-methylhexanoic acid and 2-ethylhexanoic acid, which are branched fatty acids, were prepared, and a polyol ester oil was synthesized using these as raw materials.

It was 5.3 mm < ² > / s when the kinematic viscosity in 100 degreeC of the obtained polyol ester oil was measured based on JISK2283.

  To the resulting polyol ester oil, 0.1 mass% of 2,6-di-tert-butyl-p-cresol as an oxidizing agent and 0.5 mass% of a glycidyl ester type epoxy compound as an acid scavenger were added. A refrigerating machine oil was prepared. When the low-temperature two-layer separation temperature of the refrigerating machine oil with the R448A refrigerant is measured according to “Compatibility test method with refrigerant” defined in Appendix D of JIS K2211-2009, a value lower than −47 ° C. Met.

  The obtained R448A refrigerant and refrigerator oil were accommodated in a 3HP inverter refrigerator, and the behavior of the refrigerator oil in the cycle was examined. As a result, the oil level of the refrigerating machine oil stored in the compressor oil was not significantly lowered, and the refrigerating machine oil had good oil return properties.

  However, in a durability test under an overload condition of 1000 hours, abnormal wear of the sliding members (rollers and blades) occurred, and stable lubricity was not obtained over a long period of time.

  When the low temperature side two-layer separation temperature between the refrigerating machine oil and the R448A refrigerant is higher than −37 ° C., using these refrigerating machine oil and the R448A refrigerant, the low temperature refrigeration apparatus in which the evaporation temperature is −42 ° C. Experience shows that oil return tends to deteriorate.

  Therefore, from the result of such an example, by using a refrigerating machine oil composed of polyol ester-based lubrication in which the low temperature side two-layer separation temperature between the R448A refrigerant and the refrigerant is −42 ° C. ± 5 ° C., the sliding member is used. A highly reliable hermetic compressor that provides stable lubrication over a long period of time and has good oil return properties can be realized.

  In addition, although R448A refrigerant was used in Example 1, the same effect can be acquired even if it uses R449A refrigerant.

<Second Embodiment>
The hermetic compressor according to the second embodiment is provided in the refrigeration cycle as in the first embodiment, and includes a hermetic container, a compressor unit that compresses the refrigerant stored in the hermetic container, An electric motor unit that is housed in a hermetic container and drives the compressor unit, and a refrigerating machine oil built in the hermetic container. Further, as in the first embodiment, the refrigerant is 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass. % Of 1,1,1,2-tetrafluoroethane and the refrigerating machine oil is a polyol ester-based lubricating oil having a low-temperature side two-layer separation temperature of −42 ° C. ± 5 ° C. with respect to the refrigerant.

The hermetic compressor is further provided with an injection pipe that guides the liquid refrigerant of the refrigeration cycle to the compressor section, and the operating conditions of the compressor section include the contact pressure between the rollers 27 and 28 and the blades 30 and 31, and the sliding speed. Is set so that the PV value between the roller and the blade is 0.3 × 10 ^{9 to} 1.5 × 10 ⁹ Pa · m / sec. Here, the operating condition is any one of a pressure difference between the sealed container and the cylinder chamber, a suction pressure and a discharge pressure, a rotation speed of the rollers, and an outer diameter of the aligned rollers.

  As described with reference to FIGS. 1 and 2, the injection pipe uses an intermediate partition plate 20 that forms part of the refrigerant (including refrigerating machine oil) liquefied by the condenser 2 from the gas-liquid separator 3 and constitutes an injection mechanism. To the first and second lateral holes 35, the flow is diverted to the first injection port 36a and the second injection port 36b. The liquid refrigerant is guided from the first injection port 36a to the first cylinder chamber 18A, and is injected into the gas refrigerant in the middle of compression in the first cylinder chamber 18A, thereby cooling the gas refrigerant. Further, the liquid refrigerant is guided from the second injection port 36b to the second cylinder chamber 22A and is injected into the gas refrigerant in the middle of compression in the second cylinder chamber 22A to cool the gas refrigerant. Thus, by performing efficient cooling, it is possible to improve the compression performance.

  However, at the blade tip where it is difficult to supply the refrigerating machine oil, the liquid refrigerant becomes excessive with the injection cooling, and the viscosity of the refrigerating machine oil diluted with the liquid refrigerant is locally reduced. For this reason, the roller of the compressor section is abnormally worn due to poor lubrication.

According to the second embodiment, the pressure condition of the compressor unit is set so that the PV value between the roller and the blade is 0.3 × 10 ^{9 to} 1.5 × 10 ⁹ Pa · m / sec. Can prevent abnormal wear of the rollers of the compressor section, and thus a highly reliable hermetic compressor can be realized.

  Here, the upper limit of the PV value is defined from the limit on the material usage of the roller and the blade. The upper limit of the PV value will be specifically described with reference to FIG. 4 showing the relationship between the PV value and the outer surface roughness of the roller.

A roller made of flake graphite cast iron containing molybdenum, nickel and chromium, and a blade whose base material was made of stainless steel (for example, SUS440C) and whose surface was nitrided were prepared. The reference conditions when sliding between the roller and the blade are Pd / Ps = 2.2 MPa / 0.3 MPa (where Pd is the discharge pressure and Ps is the suction pressure), the rotational speed is 80 rps, injection cooling is performed, and The endurance test was performed for 2000 hours by setting the pressure condition so that the PV value was about 1.32 × 10 ⁹ Pa · m / sec within the above range. As a result, as shown in FIG. 4, the outer surface roughness of the roller is about 1.3 Rz, which is much lower than 2.5 Rz (which is represented by the transverse fracture line in FIG. 4) where the abnormal wear occurs. It was confirmed that abnormal wear of the roller could be prevented.

In contrast, injection cooling was performed under the same conditions, and the pressure condition was set so that the PV value was about 1.52 × 10 ⁹ Pa · m / sec outside the above range, and the durability test was performed for 2000 hours. Executed. As a result, as shown in FIG. 4, the surface roughness is about 3.3 Rz, which is higher than 2.5 Rz at which abnormal wear of the roller occurs, and the abnormal wear of the roller cannot be prevented.

Therefore, the upper limit of the PV value is defined as 1.5 × 10 ⁹ Pa · m / sec from the viewpoint of preventing abnormal wear of the roller.

On the other hand, the lower limit of the PV value (0.3 × 10 ⁹ Pa · m / sec) is that the relative speed of the roller is insufficient and the refrigeration oil is not drawn between the roller and the blade. Is defined from the limit that stops and causes local wear.

FIG. 5 shows the relationship between the number of rotations of the roller and the PV value between the roller and the blade during operation at an evaporation temperature of −40 ° C. and a condensation temperature of 50 ° C. in the refrigeration cycle. It can be seen that when the PV value is less than 0.3 × 10 ⁹ Pa · m / sec, the rotation speed of the roller is less than 3 rps at which the refrigerating machine oil is sufficiently supplied between the roller and the blade.

  Therefore, according to the hermetic compressor according to the second embodiment, it is possible to achieve a good oil return property and to impart a stable lubricity over a long period of time to a sliding member including a roller and a blade. Thus, abnormal wear of the roller can be prevented more reliably.

<Third Embodiment>
The hermetic compressor according to the third embodiment is provided in the refrigeration cycle as in the first embodiment, the hermetic container, the compressor unit that compresses the refrigerant stored in the hermetic container, An electric motor unit that is housed in a hermetic container and drives the compressor unit, and a refrigerating machine oil built in the hermetic container. Further, as in the first embodiment, the refrigerant is 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass. % Of 1,1,1,2-tetrafluoroethane and the refrigerating machine oil is a polyol ester-based lubricating oil having a low-temperature side two-layer separation temperature of −42 ° C. ± 5 ° C. with respect to the refrigerant.

  In the hermetic compressor, the compressor part is a roller made of flake graphite cast iron containing molybdenum, nickel and chromium, and the base material is made of a metal material, and the surface roughness Ra (arithmetic average roughness) is 0.05 to 0.2 blade, and further includes an injection pipe for guiding the liquid refrigerant of the refrigeration cycle to the compressor section.

  By defining the surface roughness Ra of the blade within the above range, abnormal wear of the roller sliding with the blade can be prevented. If the surface roughness Ra of the blade is less than 0.05, the effect of preventing abnormal wear of the roller is not improved, and super polishing finish is required, which may increase the cost. When the surface roughness Ra of the blade exceeds 0.2, it becomes difficult to prevent abnormal wear of the roller.

  The blade is preferably coated with diamond-like carbon (DLC), which has a high effect of preventing abnormal wear of the roller, on the surface of a base material made of a metal material such as SKH51 (high speed tool steel).

  As described with reference to FIGS. 1 and 2, the injection pipe uses an intermediate partition plate 20 that forms part of the refrigerant (including refrigerating machine oil) liquefied by the condenser 2 from the gas-liquid separator 3 and constitutes an injection mechanism. The first and second injection ports 36a and 36b are diverted through the tip of the horizontal hole 35. The liquid refrigerant is guided from the first injection port 36a to the first cylinder chamber 18A, and is injected into the gas refrigerant in the middle of compression in the first cylinder chamber 18A, thereby cooling the gas refrigerant. Further, the liquid refrigerant is guided from the second injection port 36b to the second cylinder chamber 22A and is injected into the gas refrigerant in the middle of compression in the second cylinder chamber 22A to cool the gas refrigerant. Thus, by performing efficient cooling, it is possible to improve the compression performance.

  However, at the blade tip where it is difficult to supply the refrigerating machine oil, the liquid refrigerant becomes excessive with the injection cooling, and the viscosity of the refrigerating machine oil diluted with the liquid refrigerant is locally reduced. For this reason, the roller of the compressor section is abnormally worn due to poor lubrication.

  According to the third embodiment, by setting the surface roughness Ra of the blade sliding with the roller to 0.05 to 0.2, abnormal wear of the roller of the compressor portion can be prevented, and the sealing is highly reliable. A mold compressor can be realized.

  Hereinafter, the durability test of the roller incorporated in the compressor part of the hermetic compressor according to the third embodiment will be specifically described.

(Example 11)
A roller made of flake graphite cast iron containing molybdenum, nickel and chrome, and a diamond-like carbon (DLC) coating on the surface of the base material made of SKH51, and a blade having a surface roughness Ra of 0.1 are sealed. It was incorporated in the compressor section of the mold compressor.

(Example 12)
A roller made of flake graphite cast iron containing molybdenum, nickel and chromium, and a blade made of SUS440C, having a nitriding surface and a surface roughness Ra of 0.2, are incorporated in the compressor section of the hermetic compressor. It is.

(Comparative Example 11)
A roller made of molybdenum nickel chrome cast iron and a blade made of SUS440C, the surface of which was nitrided, and having a surface roughness Ra of 0.4 were incorporated in the compressor section of the hermetic compressor.

  For the hermetic compressors of Examples 11 and 12 and Comparative Example 11, the reference conditions for sliding between the roller and the blade were Pd / Ps = 2.2 MPa / 0.3 MPa (where Pd is the discharge pressure and Ps is the suction) The durability test was performed for 2000 hours, in which the pressure was set to 80 rpm and the injection cooling was performed. The result is shown in FIG.

  As apparent from FIG. 6, in the hermetic compressors of Examples 11 and 12 having blades having a surface roughness Ra in the range of 0.05 to 0.2, the surface roughness of the rollers causes abnormal wear. .5Rz (represented by the transverse break line in FIG. 6), the value is low, and it can be seen that abnormal wear of the roller can be prevented. In particular, the hermetic compressor of Example 11 made of DLC and having a blade with a surface roughness Ra of 0.1 has a roller surface roughness of about 0.6 Rz, which can further prevent abnormal wear of the roller. I understand.

  In contrast, in the hermetic compressor of Comparative Example 11 having a blade with a surface roughness Ra greater than 0.2, the surface roughness of the roller is about 3.7 Rz, which is greater than 2.5 Rz, which causes abnormal wear. Unable to prevent abnormal wear.

  DESCRIPTION OF SYMBOLS 1 ... Sealed compressor, 2 ... Condenser, 3 ... Gas-liquid separator, 4 ... Expansion valve, 5 ... Evaporator, 10 ... Sealed container, 11 ... Electric motor part, 13 ... Rotary shaft, 18 ... 1st cylinder 22 ... second cylinder, 27,28 ... roller, 30,31 ... blade, Pa ... injection tube, S ... refrigeration oil.

Claims (6)

A hermetic compressor provided in a refrigeration cycle, comprising a hermetic container, a compressor part that is stored in the hermetic container and compresses a refrigerant, an electric motor part that drives the compressor part, and refrigeration oil,
The refrigerant is 20% by mass or more of difluoromethane, 20% by mass or more of pentafluoroethane, 20% by mass or more of 2,3,3,3-tetrafluoropropene and 20% by mass or more of 1,1,1,2 -A hermetic compressor containing tetrafluoroethane, wherein the refrigerating machine oil uses a polyol ester-based lubricating oil having a low temperature side two-layer separation temperature of -42 ° C ± 5 ° C with the refrigerant. The compressor unit includes a cylinder that forms a cylinder chamber, a roller that rotates in the cylinder chamber, a blade that reciprocates in contact with an outer peripheral surface of the roller, and an injection mechanism that guides liquid refrigerant into the cylinder chamber,
The roller is formed from flake graphite cast iron containing molybdenum, nickel and chromium, and the blade is formed from stainless steel whose surface is nitrided,
The PV value between the roller and the blade, which is the product of the contact pressure between the roller and the blade of the compressor section and the sliding speed, is 0.3 × 10 ^{9 to} 1.5 × 10 ⁹ Pa · m / sec. The hermetic compressor according to claim 1, wherein   The compressor section is a cylinder that forms a cylinder chamber, a roller that rotates in the cylinder chamber and is made of flake graphite cast iron containing molybdenum, nickel, and chromium, and a reciprocating motion in contact with the outer peripheral surface of the roller. And a blade having a base material made of a metal material and having a surface roughness Ra of 0.05 to 0.2, and an injection mechanism for introducing liquid refrigerant into the cylinder chamber. Hermetic compressor.   4. The hermetic compressor according to claim 3, wherein the blade has a surface treated with diamond-like carbon.   The hermetic compressor according to any one of claims 1 to 4, a radiator connected to the hermetic compressor, an expansion device connected to the radiator, the expansion device and the hermetic compressor And 20 mass% or more of difluoromethane, 20 mass% or more of pentafluoroethane, 20 mass% or more of 2,3,3,3-tetrafluoropropene, and 20 mass%. A refrigerant containing 1% or more of 1,1,1,2-tetrafluoroethane is sealed.   6. The refrigeration cycle apparatus according to claim 5, wherein the evaporation temperature is set to −42 ° C. or higher.

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