JP2008151044A - Compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-efficiency compressor for a low-GWP refrigerant which is used for solving a problem where, in a refrigerator having a low environmental load and using carbon dioxide as a refrigerant, power consumption of the compressor is increased by polyalkylene glycol oil. <P>SOLUTION: By using a refrigerant having a GWP below 150, and using mixed oil of polyalkylene glycol oil having kinetic viscosity of 20-200 mm<SP>2</SP>/s at 40°C, and ester oil, and by setting the kinetic viscosity at 40°C of the polyalkylene glycol oil higher than that of the ester oil, kinetic viscosity in a high-temperature region can be lowered, and power loss by viscosity can be restrained. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a compressor used in a refrigeration apparatus with a low environmental load.

  Conventionally, this type of compressor is disclosed in Patent Document 1.

FIG. 2 shows the refrigeration apparatus described in Patent Document 1. As shown in FIG. As shown in FIG. 2, a refrigeration apparatus that circulates carbon dioxide as a refrigerant in a refrigeration circuit including a compressor 30, a radiator 31, an expansion mechanism 32, and an evaporator 33, and has a viscosity as refrigeration oil used for the compressor 30. It uses polyalkylene glycol refrigerating machine oil having a volume resistivity of 10 ⁸ Ω · cm or more at 40 ° C. and a pour point of −30 ° C. or less when carbon dioxide is saturated and dissolved. is there.
Japanese Patent No. 3600108

  In the conventional configuration, the return of the refrigerating machine oil to the compressor 30 is surely good, and there is a possibility of exhibiting an effect in preventing seizure. However, the polyalkylene glycol refrigerating machine oil is a refrigerating machine oil having a high viscosity index and a small decrease in kinematic viscosity in a high temperature region because of its helical molecular structure. Therefore, if low temperature fluidity is ensured by the polyalkylene glycol refrigerating machine oil, the kinematic viscosity in the high temperature region must be relatively high. As a result, power consumption in the compressor 30 in a high temperature atmosphere increases, and the suppression thereof is a problem.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a highly efficient compressor for a low GWP refrigerant.

In order to solve the conventional problems, a refrigerant having a GWP of 150 or less and a mixed oil of a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s are used. The kinematic viscosity of the alkylene glycol oil is set higher than that of the ester oil.

  As a result, on the one hand, the low-temperature fluidity is maintained moderately, and on the other hand, the kinematic viscosity in the high-temperature region is lowered, and the power loss caused by the viscosity in the sliding part such as the bearing can be suppressed.

  The compressor of the present invention is for a low GWP refrigerant with a small environmental load, and can improve its efficiency.

The first invention uses a mixed oil of a refrigerant having a GWP of 150 or less, a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s, and a polyalkylene glycol oil at 40 ° C. By setting the kinematic viscosity higher than that of the ester oil, the kinematic viscosity in the high temperature region is lowered, and power loss in a sliding portion such as a compressor bearing can be suppressed.

The second invention uses a mixed oil of a refrigerant having a GWP of 150 or less, a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s, and the polyalkylene glycol oil at 40 ° C. By setting the kinematic viscosity lower than that of the ester oil, the lubricity in the high temperature region is enhanced, and the operating range of the compressor can be expanded.

  In the third invention, in particular, the ester oil of the first or second invention uses a fatty acid having a branch in the vicinity of the terminal, thereby improving the stability of the ester oil. Contamination resistance can be improved.

  In the fourth aspect of the invention, in particular, the refrigerant of the first or second aspect is carbon dioxide, so that the GWP of the refrigerant becomes 1.0, and the environmental load due to the refrigerant can be minimized.

  In the fifth invention, in particular, the refrigerant of the first or second invention is a mixed refrigerant, and by providing a difference in the polarity of the constituent refrigerant, the refrigerant having a large polarity is well dissolved in the mixed oil. The return of the mixed oil from the evaporator to the compressor can be improved.

  In the sixth aspect of the invention, in particular, one of the constituent refrigerants in the mixed refrigerant of the fifth aspect is made incompatible with the mixed oil, so that the refrigerant dissolved in the mixed oil is limited. Performance can be stabilized.

  In the seventh aspect of the invention, in particular, by providing the injection mechanism in the compression mechanism portion in the compressor of the first or second aspect of the invention, the heat absorption capability of the evaporator is improved, and the efficiency of the refrigeration apparatus can be improved. .

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a longitudinal sectional view showing the overall configuration of a scroll compressor for a refrigeration apparatus according to a first embodiment of the present invention.

  In FIG. 1, 1 is a scroll compressor, 2 is a condenser, 3 is a first pressure reducing device, 4 is a gas-liquid separator, 5 is a second pressure reducing device, and 6 is an evaporator, which are sequentially connected. Constitutes the refrigeration cycle.

  Reference numeral 7 denotes an airtight container, in which an electric motor 8 and a compression mechanism 9 are arranged. The compression mechanism 9 includes a crankshaft 10 driven by an electric motor 8, a turning scroll 11, a fixed scroll 12, and an Oldham ring 13 that supports the turning scroll 11 to make a turning motion without rotating with respect to the fixed scroll 12. And the frame 14 for supporting the Oldham ring 13 so as to be movable for the support.

  The crankshaft 10 is supported by bearings 16 and 17 of the frame 14. A shaft 11 a of the orbiting scroll 11 is supported by a bearing 10 c provided on the crank portion 10 a of the crankshaft 10, and is engaged with the fixed scroll 12 to form a compression chamber 15. In addition, 18 is an inlet and 19 is an outlet.

  Reference numeral 22 of the sealed container 7 is a suction pipe connected to the evaporator 6, and 23 is a discharge pipe connected to the condenser 2. An injection tube 24 connects the gas-liquid separator 4 and the compression chamber 15 of the compression mechanism 9 via the sealed container 7.

  An oil sump 20 is provided in the lowermost part of the sealed container 7, and the lubricating oil 21 in the oil sump 20 is supplied to the lubrication target portion through the oil supply passage 10 b of the crankshaft 10, but the bearing 16 has an oil supply hole. 10d.

Lubricating oil 21 is a mixed oil of polyalkylene glycol oil and ester oil, both of which are highly soluble because of their high polarity. The kinematic viscosity at 40 ° C. is 20 to ²⁰⁰ mm ² / s, and the kinematic viscosity of the polyalkylene glycol oil at 40 ° C. is set higher than that of the ester oil. Polyalkylene glycol with a high viscosity index ensures low-temperature fluidity of the mixed oil, while ester oil with a low viscosity index sets the kinematic viscosity in the high-temperature region of the mixed oil low. Since the high pressure viscosity is high, the lubricity of the mixed oil in the high temperature region is sufficiently high. The ester oil is composed of a tetravalent alcohol such as pentaerythritol and a linear fatty acid having a relatively long branch near the end. This straight chain fatty acid sterically covers the double bond of oxygen and protects it from contamination, but the alcohol is preferably trivalent or higher, and the straight chain fatty acid is preferably longer than 2-ethylhexanoic acid. Incidentally, the kinematic viscosity at 40 ° C. mixing oil insufficient lubricity is less than 20mm ² / s, 200mm ² / is s greater than the power loss increases, kinematic viscosity at 40 ° C. for mixing oil 40～130Mm ² / S is more preferable.

  The refrigerant is carbon dioxide, GWP is as low as 1.0, and the refrigerant has the smallest environmental load.

  About the scroll compressor 1 comprised as mentioned above, the operation | movement and an effect | action are demonstrated below.

  When the crankshaft 10 is rotated by being driven by the electric motor 8, the orbiting scroll 11 is swung through the Oldham ring 13 and sucks the gas refrigerant from the suction pipe 22 to the suction port 18. In the compression chamber 15, the gas refrigerant is compressed while being reduced in volume while being moved from the outer peripheral side leading to the suction port 18 to the inner peripheral side leading to the discharge port 19, and discharged from the discharge port 19 into the sealed container 7. The high-temperature and high-pressure gas refrigerant is supplied to the refrigeration cycle from the discharge pipe 23, but is liquefied by the condenser 2, depressurized by the first decompression device 3, becomes two-phase, and reaches the gas-liquid separator 4. Here, the refrigerant is separated, and the liquid refrigerant is further decompressed by the second decompression device 5, gasified by the evaporator 6, and reaches the suction pipe 22 of the scroll compressor 1. On the other hand, the gas refrigerant separated by the gas-liquid separator is introduced into the compression chamber 15 of the compression mechanism 9 via the injection pipe 24 and compressed together with the suction gas refrigerant.

  The sliding portions of the crankshaft 10, the Oldham ring 13 and the orbiting scroll 11 have portions where high surface pressure is locally generated, but the high pressure viscosity of the ester oil acts to ensure lubricity. In addition, the effect of kinematic viscosity appears in other portions, power loss due to viscosity in each sliding portion is suppressed, and the efficiency of the scroll compressor 1 can be increased.

  In addition, since the straight chain fatty acid having a branch near the end three-dimensionally protects the double bond of oxygen, the stability of the ester oil is increased, so that not only the scroll compressor 1 but also the refrigeration apparatus has improved contamination resistance. it can.

  Carbon dioxide has a GWP of 1.0, which not only minimizes the environmental burden, but also has good compatibility with ester oil, so the mixed oil does not separate into two layers in the evaporator 6 and is therefore high in the evaporator 6. Heat transfer performance is also obtained. As a result, the evaporator 6 can be reduced in size.

Moreover, since the refrigeration effect is increased by the liquid refrigerant separated by the gas-liquid separator 4, the heat absorption capability of the evaporator 6 is improved. However, the heat transfer performance of the evaporator 6 is improved by the compatibility of ester oil and carbon dioxide. For this reason, since the heat absorption capability of the evaporator 6 is further increased, the efficiency of the refrigeration apparatus can be improved.

  Further, by using two types of refrigerant as the refrigerant, the polarity of the constituent refrigerant, in particular, the dipole moment is set to a difference of 0.5 debye or more, preferably 1.0 debye or more, so that the refrigerant having a large polarity is mixed oil. Therefore, the return of the mixed oil from the evaporator 6 to the scroll compressor 1 can be improved.

  In addition, by making one of the constituent refrigerants of the two types of mixed refrigerants incompatible with the mixed oil, only one type of refrigerant is dissolved in the mixed oil, so the performance of the scroll compressor 1 is improved. Can be stabilized.

Using a refrigerant having a GWP of 150 or less and a mixed oil of a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s, the kinematic viscosity of the polyalkylene glycol oil at 40 ° C. is higher than that of the ester oil. By setting it low, the kinematic viscosity in the high temperature region is kept relatively high by the polyalkylene glycol having a high viscosity index, and the lubricity of the mixed oil is enhanced by the action of the high-pressure viscosity of the ester oil. You can drive. That is, the operating range of the scroll compressor 1 can be expanded.

  As described above, the compressor according to the present invention reduces the kinematic viscosity in the high temperature region by the mixed oil of the polyalkylene glycol oil and the ester oil and suppresses power loss in the sliding portion. It can also be applied to automotive air conditioners.

The longitudinal cross-sectional view of the scroll compressor in Embodiment 1 of this invention Refrigeration cycle diagram showing the concept of conventional refrigeration equipment

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Scroll compressor 9 Compression mechanism 10 Crankshaft 11 Orbiting scroll 13 Oldham ring 21 Lubricating oil

Claims (7)

Using a refrigerant having a GWP of 150 or less and a mixed oil of a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s, the kinematic viscosity of the polyalkylene glycol oil at 40 ° C. is higher than that of the ester oil. Highly set compressor. Using a refrigerant having a GWP of 150 or less and a mixed oil of a polyalkylene glycol oil and an ester oil having a kinematic viscosity at 40 ° C. of ²⁰ to 200 mm ² / s, the kinematic viscosity of the polyalkylene glycol oil at 40 ° C. is higher than that of the ester oil. Compressor set low. The compressor according to claim 1 or 2, wherein the ester oil is a fatty acid having a branch near the end. The compressor according to claim 1 or 2, wherein the refrigerant is carbon dioxide. The compressor according to claim 1 or 2, wherein the refrigerant is a mixed refrigerant, and a difference is provided in the polarity of the constituent refrigerant. The compressor according to claim 5, wherein one of the refrigerants constituting the mixed refrigerant is hardly compatible with the mixed oil. The compressor according to claim 1 or 2, wherein an injection mechanism is provided in the compression mechanism section.

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