JP2010243148A - Refrigeration cycle equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerating cycle device having a compressor of high reliability by preventing the compressor from being kept in a high temperature state due to sliding heat. <P>SOLUTION: A piston 9 eccentrically rotated by a shaft 4 is disposed in a cylinder 6, a circular arc-shaped tip section 10a of a vane 10 partitioning the inside of the cylinder 6 into a suction chamber 12 and a compression chamber 13 is slidably engaged with an outer periphery of the piston 9 and kept into face-contact therewith, thus the sliding heat is suppressed, degradation of reliability due to reaction of a working refrigerant can be prevented, and the refrigerating cycle device having the compressor of low cost can be provided. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a room air conditioner in which a working fluid is a refrigerant mainly composed of carbon and a hydrofluoroolefin having a double bond between carbons that does not contain chlorine atoms and has a low global warming potential, and a rotary compressor is mounted on the compressor. The present invention relates to a highly reliable refrigeration cycle apparatus such as a refrigerator and an air conditioner.

  In the conventional refrigeration cycle apparatus, the HFC (hydrofluorocarbon) system having zero ozone depletion coefficient has been transferred as a working refrigerant, but this HFC refrigerant has become a problem in recent years because of its extremely high global warming potential. Yes. Therefore, a refrigeration cycle apparatus using a refrigerant mainly containing hydrofluoroolefin having no chlorine atom and low global warming potential and a double bond between carbons has been considered. With respect to the sliding material of this type of rotary compressor used in conventional HFC-based refrigerants, various devices have been made to ensure reliability (for example, see Patent Document 1).

  FIG. 5 is a cross-sectional view of a rotary compressor used under the conventional HFC (hydrofluorocarbon) refrigerant described in Patent Document 1. A piston 43 is inserted into the inner surface of the cylinder 41, rotates with the rotation of the shaft 42, and sucks and compresses refrigerant gas in a suction chamber 45 and a compression chamber 46 partitioned by a vane 44. The place where the wear is severe due to the structure of the rotary compressor is the place where the tip of the vane 44 and the outer periphery of the piston 43 are in contact with each other. Since the tip of the vane 44 is pressed against the outer periphery of the piston 43 by line contact with a larger force, the surface pressure is increased and boundary lubrication is performed. Further, nitriding treatment is applied to the vanes, and CrN or TiN ion plating is applied to the surface thereof to improve wear resistance and ensure reliability.

  FIG. 6 is a cross-sectional view of a swing rotary compressor used under the conventional HFC (hydrofluorocarbon) refrigerant described in Patent Document 2. The piston 53 is composed of a roller 53a and a vane 54 formed integrally with the roller 53a, and the vane 54 is swingable in a cylindrical hole 51a provided outside the inner surface of the cylinder 51. 57, the piston 53 is inserted into the inner surface of the cylinder 51, swings with the rotation of the shaft 52, and sucks and compresses the refrigerant gas in the suction chamber 55 and the compression chamber 56 partitioned by the vane 54. It is a swing rotary compressor.

  Unlike the rotary compressor described in Patent Document 1, the swing rotary compressor has a semi-cylindrical sliding member instead of the contact between the tip of the vane and the outer periphery of the piston, because the roller 53a and the vane 54 have an integral structure. And the cylindrical hole 51a provided in the cylinder 51 are in surface contact with each other, and the sliding state is relaxed.

JP 11-236890 A JP 2003-106692 A

However, when considering a rotary compressor of a refrigeration system mainly composed of a hydrocarbon that does not contain chlorine atoms and has a low global warming potential and a hydrofluoroolefin having a double bond between carbons, the tip of the vane and the outer periphery of the piston In a harsh environment where the surface pressure is increased due to the pressure of the line contact, boundary lubrication occurs, and the temperature is high due to sliding heat, it reacts with the refrigerant to generate hydrogen fluoride, which is against the vane tip and piston outer periphery. There was a problem in which the wear was promoted or the refrigerating machine oil was deteriorated, leading to a decrease in reliability. Further, in a refrigeration apparatus having a long pipe, in order to recover the refrigeration oil discharged from the rotary compressor, it is necessary to use a refrigeration oil compatible with the refrigerant, such as polyvinyl ethers and polyol esters. Refrigerating machine oil is prone to contain moisture, and thus more likely to generate hydrogen fluoride. Also, there is a problem of generating fatty acids by hydrolysis and causing problems such as clogging capillary tubes used in the squeezing mechanism of the refrigeration cycle. It was. In the case of a swing compressor configuration, the contact surface changes from line contact to surface contact and sliding is mitigated. However, since the piston is an integral structure of the roller and vane, it is very costly to process accurately. It was over. In addition, two new sliding members with strict processing accuracy requirements are required, resulting in an increase in the number of parts and an increase in cost.

  The present invention has been made in view of such problems of the prior art, and by changing the contact between the vane tip and the outer periphery of the piston from line contact to surface contact, the sliding heat is lowered to reduce the reliability of the compressor. It is an object of the present invention to obtain an inexpensive compressor while keeping the configuration of a conventional rotary compressor as much as possible.

  In order to achieve the above object, the refrigeration cycle apparatus of the present invention is a hydrofluoroolefin single refrigerant having a double bond between carbons, or a hydrofluoroolefin having a basic component of hydrofluoroolefin and having no double bond. A refrigerant mixed with fluorocarbon is used as a working refrigerant. A piston that rotates eccentrically with a shaft is arranged in the cylinder, and the tip of the vane that divides the inside of the cylinder into a suction chamber and a compression chamber is swingably engaged with the outer periphery of the piston. A rotary compressor characterized by being combined is connected.

  As a result, the rotary compressor is changed from the boundary lubrication state where the line contact is severe to the surface contact lubrication state because the vane tip is slidably engaged with the outer periphery of the piston. Since it does not rise, it is possible to suppress the production of hydrogen fluoride that occurs when the refrigerant reacts with moisture or oxygen.

  In the refrigeration cycle apparatus of the present invention, the tip of the vane of the rotary compressor is slidably engaged with the outer periphery of the piston to change from the boundary lubrication state where the line contact is severe to the surface contact lubrication state. Since the temperature of the part does not rise so much, it is possible to suppress the production of hydrogen fluoride generated when the refrigerant reacts with moisture and oxygen, and the carbon does not contain chlorine atoms and has a low global warming potential. A highly reliable refrigeration cycle apparatus can be obtained using a refrigerant mainly composed of hydrofluoroolefin having a heavy bond.

1 is a system configuration diagram of a refrigeration cycle apparatus according to Embodiment 1 of the present invention. 1 is a longitudinal sectional view of a rotary compressor according to a first embodiment of the present invention. Cross section of the compression mechanism of the rotary compressor Characteristic chart showing the global warming potential depending on the mixing ratio of refrigerant mixed with two components Cross-sectional view of a compression mechanism of a conventional rotary compressor Cross-sectional view of compression mechanism of conventional swing rotary compressor

The first invention uses, as a working refrigerant, a single refrigerant of hydrofluoroolefin having a double bond between carbons or a refrigerant mixed with hydrofluoroolefin having a basic component of hydrofluoroolefin and having no double bond. A compression mechanism having a motor and a shaft driven by a rotor of the motor is disposed in the sealed container, and the compression mechanism is provided with a piston that is eccentrically rotated by the shaft in the cylinder and sucks the cylinder. A rotary compressor characterized in that a tip end of a vane partitioning the chamber and the compression chamber is slidably engaged with an outer periphery of the piston, and cools the refrigerant gas compressed to a high pressure by the compressor A condenser and a throttle mechanism that depressurizes the high-pressure refrigerant liquefied by the condenser and an evaporator that gasifies the depressurized liquid refrigerant are connected by a pipe. As a result, the contact between the tip of the vane of the rotary compressor and the outer periphery of the piston becomes a swingable engagement from a strict line contact, so that the temperature rise of the sliding surface is suppressed and the fluorination due to the decomposition of the refrigerant. Generation of hydrogen can be suppressed. Further, by suppressing the generation of hydrogen fluoride, it is possible to obtain a highly reliable refrigeration cycle apparatus that suppresses wear of the vanes and the piston.

  According to a second aspect of the invention, the outer periphery of the tip of the vane and the piston of the rotary compressor according to the first aspect of the invention is slidably engaged by the arcuate tip of the vane and the arcuate notch of the outer periphery of the piston. As a result, the engaging portions are fitted in arcuate shapes so that they are in surface contact and the temperature rise due to sliding can be suppressed.

  In the third invention, polyvinyl ethers and polyol esters that are compatible with the working refrigerant are used in the refrigerating machine oil used in the rotary compressor of the first invention, so that they are discharged from the rotary compressor. Is also dissolved in the refrigerant and returns to the suction hole of the rotary compressor through the condenser, the throttle mechanism and the evaporator, so that the refrigerating machine oil in the rotary compressor is reduced and the lubrication of the sliding portion is deteriorated. Therefore, a highly reliable refrigeration cycle apparatus can be obtained.

  In the fourth invention, the working refrigerant of the first invention is such that the hydrofluoroolefin contains tetrafluoropropene as a basic component, difluoromethane and pentafluoroethane, and preferably has a global warming potential of 5 or more and 750 or less. Since refrigerants in which two components or three components are mixed are used so as to be 5 or more and 300 or less, even if unrecovered refrigerant is released into the atmosphere, the influence on global warming can be kept to a minimum.

  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 shows a system configuration diagram of a refrigeration cycle apparatus according to a first embodiment of the present invention.

  As shown in FIG. 1, the refrigeration cycle apparatus according to the present embodiment is mainly composed of a compressor 61, a condenser 62, a throttle mechanism 63, and an evaporator 64, when described as a cooling-only cycle, for example. These devices are connected by a piping set so that the refrigerant circulates.

Further, in this refrigeration cycle apparatus, a refrigerant mainly containing hydrofluoroolefin containing no chlorine atom and having a low global warming potential and a double bond between carbons is enclosed. The refrigerant sealed in the refrigeration apparatus is a hydrofluoroolefin, for example, tetrafluoropropene (HFO1234yf) as a basic component, and either or both of difluoromethane (HFC32) and pentafluoroethane (HFC125) It is a refrigerant in which two components or three components are mixed so that the conversion coefficient (GWP) is 5 or more and 750 or less, preferably 5 or more and 300 or less. Alternatively, a single refrigerant (GWP = 4) of hydrofluoroolefin may be used.

  FIG. 4 is a characteristic diagram showing a global warming potential according to a mixing ratio of a refrigerant in which two components of tetrafluoropropene and difluoromethane or pentafluoroethane are mixed. Specifically, as shown in FIG. 4, in the case of mixing two components, in order to mix tetrafluoropropene and difluoromethane to make GWP 300 or less, difluoromethane is 44 wt% or less, tetrafluoropropene and pentafluoroethane. In order to make GWP750 or less by mixing the above, pentafluoroethane is 21.3 wt% or less, and in order to make GWP300 or less, pentafluoroethane is mixed with 8.4 wt% or less.

  Also, when the refrigerant is a single refrigerant of tetrafluoropropene, it becomes GWP4 and shows a very good value. However, since the refrigerating capacity is reduced due to the large specific volume as compared with the refrigerant mixed with hydrofluorocarbon, a larger cooling cycle device is required. In other words, if a refrigerant in which a hydrofluoroolefin having a double bond between carbon and carbon is used as a basic component and a hydrofluorocarbon having no double bond is used, the refrigerant is refrigerated as compared with a single refrigerant of hydrofluoroolefin. It is possible to improve the predetermined characteristics such as capacity and make it easier to use as a refrigerant. Therefore, in the refrigerant to be sealed, the ratio of tetrafluoropropene including a single refrigerant is appropriately selected according to the purpose of the cooling cycle apparatus incorporating the compressor and the above-mentioned conditions such as the GWP restriction. That's fine.

  Even if the refrigerant | coolant which is not collect | recovered by this is discharge | released to air | atmosphere, the influence can be kept to the minimum with respect to global warming. In addition, the mixed refrigerant mixed at the above ratio can reduce the temperature difference in spite of the non-azeotropic mixed refrigerant and behaves like a pseudo azeotropic mixed refrigerant. Therefore, the cooling performance and the cooling performance coefficient (COP) of the cooling cycle device can be increased. Can be improved.

  In the refrigeration cycle apparatus configured as described above, the refrigerant changes to liquid by pressurization and cooling, and changes to gas by depressurization and heating. The compressor 61 is driven by a motor, pressurizes the low-temperature and low-pressure gas refrigerant into a high-temperature and high-pressure gas refrigerant, and is conveyed to the condenser 62. The condenser 62 is cooled and condensed by air blown by a fan or the like, and becomes a low-temperature and high-pressure liquid refrigerant. The liquid refrigerant is depressurized by the throttle mechanism 63, and part of the liquid refrigerant becomes low-temperature and low-pressure gas refrigerant, and the rest becomes low-temperature and low-pressure liquid refrigerant and is conveyed to the evaporator 64. The evaporator 64 is heated and evaporated by air blown by a fan or the like, and becomes a low-temperature and low-pressure gaseous refrigerant, which is again sucked into the compressor 61 and pressurized.

  Moreover, although the said Example demonstrated as a refrigeration cycle apparatus only for cooling, of course, it can be implemented by operating as a heating cycle apparatus via a four-way valve etc.

  FIG. 2 is a longitudinal sectional view of a rotary compressor used in the refrigeration cycle apparatus shown in FIG. A compression mechanism 5 having a shaft 4 driven by a rotor 2b and a stator 2a of a motor 2 fixed to the upper part of the sealed container 1 is fixed to the lower part of the sealed container 1. A lower bearing 8 is fixed to the upper end of the cylinder 6 of the compression mechanism 5 at the lower end of the upper bearing 7 with a bolt or the like. In the cylinder 6, a piston 9 is inserted into an eccentric portion 4 a of the shaft 4 to perform eccentric rotation. Also, the bottom of the sealed container 1 is a polyvinyl ether or polyol ester compatible with a refrigerant mixed with a hydrofluorocarbon having a double bond between carbon as a basic component and a hydrofluorocarbon having no double bond. Refrigerating machine oil 3 of the kind is stored.

  3 is a cross-sectional view of the compression mechanism portion of the rotary compressor shown in FIG. As shown in FIG. 3, the vane 10 is inserted into the vane groove 6 a of the cylinder 6, and the arcuate tip portion 10 a of the vane 10 is swingably engaged with the circular notch 9 a on the outer periphery of the piston 9. .

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

  First, refrigerant gas mixed with hydrofluoroolefin having a double bond between carbon and carbon as a basic component is sucked into a suction chamber 12 from a suction hole 11 provided in the cylinder 6. The Further, the gaseous refrigerant in the compression chamber 13 is compressed with the leftward rotation (in the direction of the arrow) of the piston 9 and is discharged from the discharge port (not shown) through the discharge notch 14. The compressed gas refrigerant discharged into the hermetic container 1 is discharged from the discharge pipe 15 at the upper part of the hermetic container 1 through the gap of the motor 2, and the mist of the refrigerating machine oil around that is also discharged together. .

  In the present invention, a high discharge pressure is applied to the back surface portion 10b of the vane 10 and a large force is exerted due to a differential pressure from the pressure in the cylinder. However, the arcuate tip portion 10a of the vane 10 has a circular shape on the outer periphery of the piston 9. Since it is slidably engaged with the notch portion 9a, it becomes a surface contact instead of a conventional line contact and does not become a severe environment of high temperature due to sliding friction. Therefore, since the sliding surface does not easily reach high temperatures, generation of hydrogen fluoride is caused by decomposition of refrigerant gas containing hydrofluoroolefin having a double bond between carbon and carbon as a basic component and mixed with hydrofluorocarbon having no double bond. Can be suppressed.

  In addition, since the refrigerating machine oil is a polyvinyl ether or polyol ester refrigerating machine oil that is compatible with the refrigerant, the refrigerating machine oil that has gone out to the refrigerating cycle can be recovered in the rotary compressor, which is highly reliable. A rotary compressor can be obtained.

  Furthermore, since the rotary compressor of the refrigeration cycle apparatus of the present invention is largely different from the conventional rotary compressor only in the shape of the vane and the piston, it is not necessary to make a major change in production facilities, so that the rotary compressor is inexpensive. A compressor can be obtained.

  As described above, the rotary compressor according to the present invention includes a refrigeration cycle apparatus even in a refrigerant mixed with a hydrofluoroolefin having a double bond between carbon and a hydrofluorocarbon having no double bond as a basic component. Since reliability can be ensured, it can also be applied to uses such as a water heater device, a car air conditioner unit, a refrigerator-freezer cycle, and a dehumidifier.

DESCRIPTION OF SYMBOLS 1 Airtight container 2 Motor 2a Stator 2b Rotor 3 Refrigerator oil 4 Shaft 4a Eccentric part 5 Compression mechanism part 6 Cylinder 6a Vane groove 7 Upper bearing 8 Lower bearing 9 Piston 9a Circular notch part 10 Vane 10a Arc-shaped tip part 10b Back portion 11 Suction hole 12 Suction chamber 13 Compression chamber 14 Discharge notch 15 Discharge pipe 61 Rotary compressor 62 Condenser 63 Throttle mechanism 64 Evaporator

Claims (4)

A single refrigerant of hydrofluoroolefin having a double bond between carbon or carbon, or a refrigerant mixed with hydrofluorocarbon having a hydrofluoroolefin as a basic component and not having a double bond as a working refrigerant, A motor and a compression mechanism that is driven by a rotor of the motor; the compression mechanism includes a piston that is eccentrically rotated by a shaft in a cylinder; and a vane that partitions the inside of the cylinder into a suction chamber and a compression chamber A rotary compressor characterized in that a tip part is slidably engaged with the outer periphery of the piston, a condenser for cooling the refrigerant gas compressed to a high pressure by the compressor, and liquefied by the condenser Refrigeration cycle apparatus configured by connecting a throttling mechanism for decompressing the decompressed high-pressure refrigerant and an evaporator for gasifying the decompressed liquid refrigerant via a pipe The refrigeration cycle according to claim 1, wherein the tip of the vane of the rotary compressor and the outer periphery of the piston are slidably engaged by the arc-shaped tip of the vane and the arc-shaped notch on the outer periphery of the piston. apparatus. The refrigeration cycle apparatus according to claim 1, wherein polyvinyl ethers or polyol esters compatible with the working refrigerant are used in the refrigerating machine oil. The working refrigerant is a hydrofluoroolefin whose main component is tetrafluoropropene, and difluoromethane and pentafluoroethane so that the global warming potential is 5 or more and 750 or less, preferably 5 or more and 300 or less. The refrigeration cycle apparatus according to claim 1, wherein each of the two components or the three components is mixed.