JP2009109157A - Refrigerant circulation circuit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerant circulation circuit cooling lubricating oil separated by an oil separator, and cooling refrigerant gas of a suction chamber. <P>SOLUTION: The refrigerant circulation circuit 10 comprises: a compressor C1; the oil separator 52 disposed to a discharge path of the refrigerant gas from a compression mechanism of the compressor C1 to separate the lubricating oil contained in the refrigerant gas; a condenser 41; an expansion valve 42; and an evaporator 43. The refrigerant circulation circuit 10 further comprises an oil return passage 55 returning the lubricating oil separated from the refrigerant gas by the oil separator 52 to the suction chamber 31 and a crank chamber 15. The refrigerant circulation circuit 10 further comprises; a liquid refrigerant jacket 57 disposed on the oil return passage 55; a liquid refrigerant leading passage 65 connecting a downstream area of the expansion valve 42 and the liquid refrigerant jacket 57; and a liquid refrigerant supply passage 69 connecting the liquid refrigerant jacket 57 with the suction chamber 31. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a refrigerant circulation circuit used for an air conditioner, and more particularly to a refrigerant circulation circuit used for a vehicle air conditioner.

  The vehicle air conditioner includes a refrigerant circulation circuit including a compressor and an external refrigerant circuit, and the external refrigerant circuit expands a condenser that condenses the refrigerant gas compressed by the compressor and a refrigerant condensed by the condenser. And an evaporator for evaporating the refrigerant expanded by the expansion valve. Further, in the compressor, lubricating oil is used for lubricating each sliding portion inside, and a part of the lubricating oil is contained in the refrigerant gas in a mist form. The lubricating oil is discharged to the external refrigerant circuit together with the refrigerant gas when the refrigerant gas compressed by the compression mechanism of the compressor is discharged and circulated to the external refrigerant circuit. If this lubricating oil adheres to the inner wall of the evaporator of the external refrigerant circuit, the heat exchange in the external refrigerant circuit is hindered. Therefore, oil that suppresses the lubricating oil contained in the refrigerant gas from being separated from the refrigerant gas and discharged to the external refrigerant circuit, and further returns the separated lubricating oil to the suction chamber (low pressure portion) in the compressor. Separator is used. As this oil separator, for example, lubricating oil is separated from refrigerant gas that is contained in a discharge chamber and discharged into the discharge chamber after compression.

  However, since the refrigerant gas discharged into the discharge chamber is a high-temperature and high-pressure gas immediately after compression, the lubricating oil separated from the high-temperature and high-pressure refrigerant gas is also at a high temperature. Therefore, if the separated lubricating oil is returned to the suction chamber in the compressor as it is, the refrigerant gas flowing into the suction chamber is also heated by the lubricating oil. And if refrigerant gas expand | swells by the heating, the density of refrigerant gas will fall compared with the case where it is not heated, and volume efficiency will fall. As a result, the refrigerant circulation amount in the refrigerant circulation circuit decreases, and the cooling capacity of the vehicle air conditioner decreases.

In view of this, a refrigerant circulation circuit (refrigerant circuit) that can cool the lubricating oil separated from the refrigerant gas has been proposed (see, for example, Patent Document 1). In this refrigerant circuit, a compressor and an oil separator (described as an oil separator in Patent Document 1) are connected by an oil return circuit. This oil return circuit is arranged so that a part thereof passes through the evaporator of the external refrigerant circuit. For this reason, the lubricating oil separated from the refrigerant gas by the oil separator passes through the oil return circuit, is cooled when passing through the evaporator, and is returned to the suction chamber in the compressor. Then, the refrigerant gas flowing into the suction chamber is suppressed from being heated by the lubricating oil.
JP-A-2005-273728

  However, in the compressor, the discharge chamber is also heated by the high-temperature and high-pressure refrigerant gas immediately after compression, and heat is transferred from the discharge chamber (high-temperature portion) to the suction chamber (low-temperature portion) (that is, heat conduction). Is heated, and the refrigerant gas in the suction chamber is heated. Therefore, in Patent Document 1, even if it is suppressed that the refrigerant gas in the suction chamber is heated by the lubricating oil by cooling the lubricating oil through the evaporator in a part of the oil return circuit, the refrigerant gas This is heated by the heat from the discharge chamber. Patent Document 1 does not suggest any cooling of the refrigerant gas in the suction chamber.

  An object of the present invention is to provide a refrigerant circulation circuit capable of cooling lubricating oil separated by an oil separator and further cooling refrigerant gas in a suction chamber.

  In order to solve the above problems, the invention according to claim 1 is a compression configured to suck and compress the refrigerant gas that has flowed into the suction chamber inside the housing into the compression mechanism and discharge it to the discharge chamber. An oil separator that is disposed in a refrigerant gas discharge path from the compression mechanism and separates lubricating oil contained in the refrigerant gas; a condenser that condenses the refrigerant gas after passing through the oil separator; An expansion valve for expanding the refrigerant condensed by the condenser; an evaporator for evaporating the refrigerant expanded by the expansion valve; and a lubricating oil separated from the refrigerant gas by the oil separator from the discharge path. An oil return passage for returning to liquid and a liquid refrigerant that has passed through the expansion valve and before flowing into the evaporator are introduced, and the oil in the oil return passage can be cooled by the liquid refrigerant. To together, the liquid is refrigerant configured to be supplied to the suction chamber, and a said suction chamber of the refrigerant gas can be cooled and the oil cooling unit.

  According to the present invention, the high-temperature lubricating oil separated by the oil separator passes through the oil return passage and returns to the low-temperature liquid refrigerant (the expansion valve and the evaporator) before returning to the suction chamber. Is cooled by boiling cooling of the liquid refrigerant before flowing into the liquid. Therefore, the refrigerant gas in the suction chamber is prevented from being heated by the lubricating oil returned to the suction chamber. Even if the refrigerant gas in the suction chamber is heated by heat conduction or the like from the discharge chamber, the refrigerant gas passes through the low-temperature liquid refrigerant (passing through the expansion valve and flowing into the evaporator) supplied into the suction chamber. The liquid refrigerant is cooled by boiling cooling.

  The oil cooling section connects a liquid refrigerant jacket provided on the oil return passage, a downstream area of the expansion valve, and the liquid refrigerant jacket, and introduces the liquid refrigerant into the liquid refrigerant jacket. It may be formed of an introduction passage, a liquid refrigerant supply passage connecting the liquid refrigerant jacket and the suction chamber and supplying the liquid refrigerant to the suction chamber.

  According to this, low-temperature liquid refrigerant (liquid refrigerant that has passed through the expansion valve and before flowing into the evaporator) is introduced into the liquid refrigerant jacket, and the lubricating oil in the oil return passage is cooled. Therefore, by providing the liquid refrigerant jacket, the lubricating oil can be cooled while separating the liquid refrigerant and the lubricating oil.

  The compressor is a variable capacity compressor capable of changing a discharge capacity by adjusting a pressure of a crank chamber in the housing, and the oil return passage is also provided in the crank chamber as the low pressure portion. It may be connected.

  According to this, the lubricity of each sliding portion in the crank chamber can be improved by the lubricating oil having a high viscosity cooled by the low-temperature liquid refrigerant. As a result, in the compressor, it is possible to prevent the occurrence of noise due to insufficient lubrication of each sliding portion in the crank chamber and the occurrence of problems such as friction burning.

  The oil cooling section is formed from the oil return passage, a liquid refrigerant introduction passage connecting the downstream area of the expansion valve and the oil return passage, and introducing the liquid refrigerant into the oil return passage. Yes.

  According to this, the method of cooling by directly supplying the liquid refrigerant to the lubricating oil is compared with the case of cooling the lubricating oil in the oil return passage by providing a liquid refrigerant jacket around the oil return passage. Cooling efficiency is good.

The liquid refrigerant introduction passage may be provided with a flow rate adjusting valve for adjusting the opening degree of the liquid refrigerant introduction passage.
According to this, the amount of the liquid refrigerant introduced into the oil cooling section (liquid refrigerant jacket or oil return passage) can be adjusted by the flow rate adjusting valve. For this reason, it is possible to prevent occurrence of excessive introduction or insufficient introduction of liquid refrigerant to the oil cooling section.

  According to the present invention, the lubricating oil separated by the oil separator can be cooled, and the refrigerant gas in the suction chamber can also be cooled.

(First embodiment)
Hereinafter, a first embodiment in which the refrigerant circuit of the present invention is embodied as a refrigerant circuit in a vehicle air conditioner will be described with reference to FIGS. 1 and 2.

  As shown in FIGS. 1 and 2, the refrigerant circulation circuit 10 includes a compressor C <b> 1 and an external refrigerant circuit 40. 1 shows the refrigerant circulation circuit 10 including a longitudinal sectional view of the compressor C1, and FIG. 2 is a diagram conceptually showing the refrigerant circulation circuit 10. First, the compressor C1 will be described. In the following description, the “front” and “rear” of the compressor C1 are the directions of the arrow Y1 shown in FIG. 1, and the “upper” and “lower” are the directions of the arrow Y2 shown in FIG. Is the vertical direction.

  As shown in FIG. 1, the housing of the compressor C1 includes a cylinder block 11, a front housing 12 joined to the front end (one end) of the cylinder block 11, and a valve / port at the rear end (the other end) of the cylinder block 11. It is formed from a rear housing 14 joined through a forming body 13. The cylinder block 11, the front housing 12, and the rear housing 14 are made of aluminum. A rotary shaft 16 is rotatably supported by the housing, and an engine (internal combustion engine) serving as a vehicle driving source is connected to a front end portion of the rotary shaft 16 outside the compressor C1 via a power transmission mechanism (not shown). Engine) E is operatively connected. A crank chamber 15 is formed between the cylinder block 11 and the front housing 12, and a lug plate 21 fixed to the rotary shaft 16 so as to be integrally rotatable is disposed in the crank chamber 15.

  A swash plate 22 is supported on the rotating shaft 16, and the swash plate 22 is disposed in the crank chamber 15. A hinge mechanism 23 is interposed between the swash plate 22 and the lug plate 21. The swash plate 22 can be rotated synchronously with the lug plate 21 and the rotary shaft 16 by the hinge connection with the lug plate 21 via the hinge mechanism 23 and the support of the rotary shaft 16. It can be tilted with respect to the rotating shaft 16 while being slid in the axial direction.

  In the cylinder block 11, a plurality of cylinder bores 11 a (only one cylinder bore 11 a is shown in FIG. 1) is formed so as to surround the rotating shaft 16. The single-headed piston 20 is accommodated in each cylinder bore 11a so as to be able to reciprocate. The front and rear openings of the cylinder bore 11a are closed by the valve / port forming body 13 and the piston 20, and the piston 20 is reciprocated in the cylinder bore 11a. The volume changes according to the movement, and a compression chamber 28 for compressing the refrigerant gas is defined. Each piston 20 is anchored to the outer peripheral portion of the swash plate 22 via a shoe 29. Therefore, the rotational movement of the swash plate 22 accompanying the rotation of the rotary shaft 16 is converted into the reciprocating linear movement of the piston 20 via the shoe 29, and the refrigerant gas is compressed in the compression chamber 28. In the present embodiment, the cylinder bore 11a (compression chamber 28), the piston 20, and the swash plate 22 are driven as the rotary shaft 16 rotates to constitute a compression mechanism that compresses the refrigerant gas.

  A suction chamber 31 and a discharge chamber 32 are formed between the cylinder block 11 and the rear housing 14 via the valve / port forming body 13. Corresponding to each compression chamber 28, the valve / port forming body 13 includes a suction port 33, a suction valve 34 that opens and closes the suction port 33, and a discharge port 35 and a discharge valve 36 that opens and closes the discharge port 35. Is formed.

  The discharge chamber 32 and the crank chamber 15 are connected by a supply passage 24. The crank chamber 15 and the suction chamber 31 are connected by a discharge passage 25. The refrigerant in the crank chamber 15 flows out to the suction chamber 31 through the discharge passage 25. A capacity control valve 26 is assembled to the rear housing 14. The capacity control valve 26 controls the cross-sectional area of the supply passage 24. The amount of high-pressure refrigerant gas (discharge gas) introduced into the crank chamber 15 via the supply passage 24 is adjusted by the capacity control valve 26, and the amount of gas discharged from the crank chamber 15 via the discharge passage 25 is further adjusted. And the pressure in the crank chamber 15 is determined. As a result of changing the inclination angle of the swash plate 22 in accordance with the change of the pressure in the crank chamber 15, the stroke of the piston 20, that is, the discharge capacity of the compressor C1 is adjusted. Therefore, the compressor C1 is a variable capacity type.

  In the rear housing 14, a storage chamber 50 that extends in the vertical direction is formed above the suction chamber 31, and a discharge passage 51 that connects the storage chamber 50 and the discharge chamber 32 is formed. An oil separator 52 for separating lubricating oil contained in the refrigerant gas is provided in the storage chamber 50.

  The oil separator 52 includes a separation cylinder 53 provided substantially at the center of the storage chamber 50, and a storage section 54 provided below the storage chamber 50 and below the separation cylinder 53. The separation cylinder 53 has a cylindrical shape, and is joined to the upper inner peripheral surface of the storage chamber 50 so that the cylindrical portion is coaxial with the storage chamber 50. The storage part 54 is located above the suction chamber 31.

  As shown in FIGS. 1 and 2, in the rear housing 14, one end of the oil return passage 55 is connected to the oil separator 52 (storage part 54), and the other end of the oil return passage 55 is connected to the oil separator 52. The suction chamber 31 and the crank chamber 15 are connected to a lower pressure. The lubricating oil stored in the storage portion 54 passes through the oil return passage 55 and is returned to the suction chamber 31 and the crank chamber 15 (low pressure portion). A part of the oil return passage 55 is surrounded by a liquid refrigerant jacket 57.

  The compressor C1 having the above configuration constitutes the refrigerant circulation circuit 10 (refrigeration circuit) of the vehicle air conditioner together with the external refrigerant circuit 40. The external refrigerant circuit 40 condenses the refrigerant gas that has passed through the oil separator 52, the expansion valve 42 that expands the refrigerant condensed by the condenser 41, and the refrigerant that is expanded by the expansion valve 42 evaporates. And an evaporator 43 to be made. In the refrigerant circulation circuit 10, the oil separator 52 (accommodating chamber 50) and the condenser 41 are connected by a first connection passage 61, and the condenser 41 and the expansion valve 42 are connected by a second connection passage 62. ing. The expansion valve 42 and the evaporator 43 are connected by a third connection passage 63, and the evaporator 43 and the suction chamber 31 are connected by a fourth connection passage 64.

  One end of the liquid refrigerant introduction passage 65 is connected to the third connection passage 63 that connects the expansion valve 42 and the evaporator 43, and the other end of the liquid refrigerant introduction passage 65 is connected to the liquid refrigerant jacket 57. The liquid refrigerant introduction passage 65 introduces the liquid refrigerant before passing through the expansion valve 42 and flowing into the evaporator 43 into the liquid refrigerant jacket 57. The liquid refrigerant is a low-temperature and low-pressure liquid refrigerant that has been decompressed by passing through the expansion valve 42. One end of the liquid refrigerant supply passage 69 is connected to the liquid refrigerant jacket 57, and the other end of the liquid refrigerant supply passage 69 is connected to the suction chamber 31. A part of the liquid refrigerant supplied to the liquid refrigerant jacket 57 is supplied to the suction chamber 31 through the liquid refrigerant supply passage 69. Therefore, in the first embodiment, the liquid refrigerant jacket 57, the liquid refrigerant introduction passage 65, and the liquid refrigerant supply passage 69 can cool the lubricating oil in the oil return passage 55, and An oil cooling section that can cool the refrigerant gas is formed.

  The liquid refrigerant introduction passage 65 is provided with a flow rate adjustment valve 66, and the opening degree of the liquid refrigerant introduction passage 65 can be adjusted by the flow rate adjustment valve 66. The opening degree of the flow rate adjusting valve 66 is adjusted by performing current supply control (duty ratio control) on an electromagnetic solenoid (not shown) included in the flow rate adjusting valve 66 by the control computer 67. The control computer 67 is provided with a CPU 67a and a memory 67b (see FIG. 1), and a current supply control value set based on the temperature of the suction chamber 31 is stored in the memory 67b. Further, a temperature sensor 68 for detecting the temperature of the suction chamber 31 is connected to the control computer 67 as a signal.

  Now, in the compressor C1 of the refrigerant circuit 10, the refrigerant gas in the suction chamber 31 is moved to the cylinder bore via the suction port 33 and the suction valve 34 by the movement from the top dead center position to the bottom dead center position side of each piston 20. It is sucked into 11a (compression chamber 28). The refrigerant gas sucked into the compression chamber 28 is compressed to a predetermined pressure by movement from the bottom dead center position of the piston 20 to the top dead center position side, and then is discharged through the discharge port 35 and the discharge valve 36. 32 is discharged.

  The refrigerant gas introduced into the storage chamber 50 from the discharge chamber 32 through the discharge passage 51 swirls around the separation cylinder 53, and the lubricating oil is separated from the refrigerant gas by centrifugal separation associated with the swirl. Therefore, the discharge chamber 32, the discharge passage 51, and the storage chamber 50 constitute a discharge path for discharging the refrigerant gas discharged from the compression chamber 28 to the external refrigerant circuit 40, and the discharge chamber 32, the discharge passage 51, and the storage chamber 50 are disposed in the storage chamber 50 on the discharge path. An oil separator 52 is provided. The lubricating oil separated from the refrigerant gas by the centrifugal separation using the separation cylinder 53 falls toward the storage portion 54 and is stored. The lubricating oil stored in the storage part 54 passes through the oil return passage 55 and is returned to the suction chamber 31 located below the storage part 54.

  Here, since the refrigerant gas compressed by the compressor C1 has a high temperature and a high pressure, the inside of the discharge chamber 32 is heated. Since the rear housing 14 is made of aluminum and has thermal conductivity, heat in the discharge chamber 32 that is a high temperature portion moves toward the suction chamber 31 that is a low temperature portion via the rear housing 14, and the suction chamber 31 is heated. The refrigerant gas in the suction chamber 31 is also heated.

  The CPU 67a of the control computer 67 controls the current supply to the electromagnetic solenoid based on the temperature of the suction chamber 31 detected by the temperature sensor 68 and the current supply control value stored in the memory 67b. The opening degree of the introduction passage 65 is adjusted. Then, depending on the opening degree of the flow control valve 66, the liquid refrigerant after passing through the expansion valve 42 passes through the liquid refrigerant introduction passage 65 and is introduced into the liquid refrigerant jacket 57 (introduced into the oil cooling section).

  In the liquid refrigerant jacket 57, the liquid refrigerant is heated to the boiling point by the heat of the lubricating oil in the oil return passage 55 passing through the liquid refrigerant jacket 57, and the liquid refrigerant boils and evaporates. The heat generated from the lubricating oil is absorbed by the large latent heat of evaporation at the time of boiling, and as a result, the lubricating oil is cooled. Most of the liquid refrigerant introduced into the liquid refrigerant jacket 57 evaporates for cooling the lubricating oil, but only a very small amount remains in the liquid refrigerant jacket 57 as a liquid.

  A very small amount of liquid refrigerant remaining in the liquid refrigerant jacket 57 is supplied to the suction chamber 31 through the liquid refrigerant supply passage 69. In the suction chamber 31, when the liquid refrigerant is heated to the boiling point by the heat of the refrigerant gas, the liquid refrigerant boils and evaporates. The heat of the refrigerant gas is absorbed by the large latent heat of evaporation at the time of boiling, and as a result, the refrigerant gas in the suction chamber 31 is cooled.

  Then, the lubricating oil cooled to the low temperature by the liquid refrigerant jacket 57 is returned to the suction chamber 31 and the crank chamber 15 through the oil return passage 55. As a result, the refrigerant gas in the suction chamber 31 is not heated by the returned lubricating oil, and the refrigerant gas itself is cooled by the liquid refrigerant. Further, in the crank chamber 15, the low-temperature lubricating oil is applied to each sliding portion such as the hinge mechanism 23 between the piston 20 and the shoe 29, the shoe 29 and the swash plate 22, and the hinge mechanism 23 by the returned lubricating oil. Is supplied.

  The opening degree of the flow control valve 66 is set such that a predetermined amount of liquid refrigerant is introduced into the liquid refrigerant jacket 57. The predetermined amount of liquid refrigerant is an amount that remains slightly even after the heated lubricating oil is boiled and cooled to a predetermined temperature by the liquid refrigerant jacket 57. The amount of the liquid refrigerant remaining in the liquid refrigerant jacket 57 is an amount necessary to boil and cool only the temperature rise of the refrigerant gas in the suction chamber 31, and the minimum amount necessary to prevent the liquid refrigerant from being sucked into the compression chamber 28. Set to

According to the first embodiment, the following effects can be obtained.
(1) The oil separator 52 is connected to the suction chamber 31 and the crank chamber 15 through an oil return passage 55, a liquid refrigerant jacket 57 is provided in the oil return passage 55, and the liquid refrigerant jacket 57 and the suction chamber 31 are further connected to each other. The refrigerant supply passage 69 connected. The liquid refrigerant after passage through the expansion valve 42 can be introduced into the liquid refrigerant jacket 57 through the liquid refrigerant introduction passage 65, and the liquid refrigerant in the liquid refrigerant jacket 57 can be supplied into the suction chamber 31 through the liquid refrigerant supply passage 69. It was. For this reason, the high-temperature lubricating oil separated by the oil separator 52 is cooled by boiling cooling with the liquid refrigerant in the liquid refrigerant jacket 57 when passing through the oil return passage 55, and the refrigerant gas in the suction chamber 31. Is also cooled by boiling cooling of the liquid refrigerant. Therefore, it is possible to prevent the refrigerant gas in the suction chamber 31 from being heated by the lubricating oil returned to the suction chamber 31, and to cool the refrigerant gas heated by heat conduction or the like from the discharge chamber 32. it can. As a result, the density of the refrigerant gas in the suction chamber 31 can be increased, the cooling capacity of the refrigerant circulation circuit 10 can be improved, and the power of the compressor C1 can be reduced.

  (2) A liquid refrigerant jacket 57 is provided in the oil return passage 55, and a liquid refrigerant introduction passage 65 connected to the downstream area of the expansion valve 42 is connected to the liquid refrigerant jacket 57. Then, the liquid refrigerant after passing through the expansion valve 42 is introduced into the liquid refrigerant jacket 57, and the lubricating oil in the oil return passage 55 is cooled. Therefore, by providing the liquid refrigerant jacket 57, the lubricating oil can be cooled while separating the liquid refrigerant and the lubricating oil.

  (3) The oil return passage 55 is connected to the crank chamber 15 so that the cooled lubricating oil can be returned to the crank chamber 15. Therefore, the lubricity of each sliding portion in the crank chamber 15 can be improved by the lubricating oil that is cooled to a low temperature and has a high viscosity. As a result, in the compressor C1, it is possible to prevent generation of noise due to insufficient lubrication of each sliding portion in the crank chamber 15 and occurrence of problems such as friction burning.

  (4) The liquid refrigerant introduction passage 65 is provided with a flow rate adjustment valve 66, and the amount of liquid refrigerant introduced into the liquid refrigerant jacket 57 can be adjusted by the flow rate adjustment valve 66. For this reason, it is possible to prevent the liquid refrigerant from being introduced excessively or insufficiently introduced into the liquid refrigerant jacket 57. As a result, for example, the excessive introduction of the liquid refrigerant into the liquid refrigerant jacket 57 can eliminate the problem that the liquid refrigerant is excessively supplied to the suction chamber 31 and causes liquid compression. Further, it is possible to eliminate the problem that the cooling ability of the lubricating oil cannot be sufficiently exhibited due to insufficient introduction of the liquid refrigerant into the liquid refrigerant jacket 57.

  (5) The temperature of the suction chamber 31 is detected by the temperature sensor 68, and the opening degree of the flow control valve 66 is adjusted based on the detected temperature of the suction chamber 31. For this reason, an appropriate amount of liquid refrigerant can be introduced into the liquid refrigerant jacket 57 in accordance with the heating state in the suction chamber 31, and the refrigerant gas in the suction chamber 31 can be efficiently cooled.

  (6) Cooling of the lubricating oil is performed by boiling cooling of the liquid refrigerant. Boiling cooling absorbs the heat of the lubricating oil when the liquid refrigerant boils, that is, by the large latent heat of vaporization accompanying the phase change (from liquid to gas). Therefore, it is possible to cool the lubricating oil more efficiently than cooling without phase change.

(Second Embodiment)
Next, a second embodiment in which the refrigerant circuit of the present invention is embodied as a refrigerant circuit in a vehicle air conditioner will be described with reference to FIG. Note that in the second embodiment described below, the same components as those in the first embodiment described above are denoted by the same reference numerals, and redundant description thereof is omitted or simplified. FIG. 3 is a diagram conceptually showing the refrigerant circulation circuit 10 of the second embodiment.

  As shown in FIG. 3, in the refrigerant circuit 10, the compressor C2 is a fixed capacity type, and in the housing, the swash plate 22 is supported by the rotating shaft 16 so as not to tilt, and a swash plate chamber (not shown). ) And the crank chamber 15 is not formed. In the refrigerant circulation circuit 10, the liquid refrigerant jacket 57 is not provided in the oil return passage 55. Further, a liquid refrigerant introduction passage 65 is directly connected to the oil return passage 55 so that the liquid refrigerant before passing through the expansion valve 42 and flowing into the evaporator 43 is directly introduced into the oil return passage 55. It has become. The other end of the oil return passage 55 is connected only to the suction chamber 31. Therefore, in the second embodiment, an oil cooling section is formed from the oil return passage 55 and the liquid refrigerant introduction passage 65.

Therefore, according to the second embodiment, in addition to the effects (5) and (6) described in the first embodiment, the following effects can be obtained.
(7) The liquid refrigerant is directly introduced into the oil return passage 55, and the lubricating oil is cooled in the oil return passage 55 by boiling cooling of the liquid refrigerant. Furthermore, since the liquid refrigerant is supplied to the suction chamber 31 through the oil return passage 55, the refrigerant gas in the suction chamber 31 is also cooled by boiling cooling of the liquid refrigerant. Therefore, the refrigerant gas in the suction chamber 31 is prevented from being heated by the lubricating oil returned to the suction chamber 31, and the refrigerant gas heated by heat conduction from the discharge chamber 32 is cooled. it can. As a result, the density of the refrigerant gas in the suction chamber 31 can be increased, the cooling capacity of the refrigerant circulation circuit 10 can be improved, and the power of the compressor C2 can be reduced. In addition, a method of directly introducing the liquid refrigerant into the oil return passage 55 and cooling the oil return passage 55 is provided by providing a liquid refrigerant jacket 57 around the oil return passage 55 and introducing the liquid refrigerant into the liquid refrigerant jacket 57. Cooling efficiency is better than when the lubricating oil is cooled.

Each embodiment may be changed as follows.
In each embodiment, the oil separator 52 may be provided separately from the compressors C1 and C2.

A temperature-sensitive cylinder may be used instead of the temperature sensor 68.
O Instead of the temperature sensor 68, the pressure in the suction chamber 31 may be detected by a pressure sensor, and the opening degree of the flow control valve 66 may be adjusted by converting the pressure into a temperature.

In the first embodiment, the other end of the oil return passage 55 may be connected only to the suction chamber 31 so that the lubricating oil is not returned to the crank chamber 15.
In each embodiment, a fixed throttle may be provided in the liquid refrigerant introduction passage 65 instead of the flow rate adjustment valve 66.

In each embodiment, the compressors C1 and C2 may be of a type that swings with the swash plate 22 supported so as to be relatively rotatable with respect to the rotating shaft 16, for example, a wobble compressor.
In each embodiment, the refrigerant circulation circuit may be applied to an air conditioner other than a vehicle.

The figure which shows the compressor and external refrigerant circuit of 1st Embodiment. The figure which shows a refrigerant | coolant circulation circuit notionally. The figure which shows notionally the refrigerant circuit of 2nd Embodiment.

Explanation of symbols

  C1, C2 ... compressor, 11 ... cylinder block forming housing, 11a ... cylinder bore forming compression mechanism, 12 ... front housing forming housing, 14 ... rear housing forming housing, 15 ... crank as low pressure part 20... Piston forming the compression mechanism, 22... Swash plate forming the compression mechanism, 28... Compression chamber forming the compression mechanism, 29... Shoe forming the compression mechanism, 31. DESCRIPTION OF SYMBOLS ... Discharge chamber (discharge path), 41 ... Condenser, 42 ... Expansion valve, 43 ... Evaporator, 50 ... Storage chamber which forms discharge path, 51 ... Discharge path which forms discharge path, 52 ... Oil separator, 55 ... Oil return passage, 57 ... Liquid refrigerant jacket forming an oil cooling section, 65 ... Liquid refrigerant introduction passage forming an oil cooling section, 66 ... Flow rate adjusting valve Liquid refrigerant supply path to form a 69 ...... oil cooling unit.

Claims (5)

A compressor configured to suck the refrigerant gas flowing into the suction chamber inside the housing into the compression mechanism, compress the refrigerant gas, and discharge the refrigerant gas to the discharge chamber;
An oil separator that is disposed in a refrigerant gas discharge path from the compression mechanism and separates lubricating oil contained in the refrigerant gas;
A condenser for condensing the refrigerant gas after passing through the oil separator;
An expansion valve for expanding the refrigerant condensed in the condenser;
An evaporator for evaporating the refrigerant expanded by the expansion valve;
An oil return passage for returning the lubricating oil separated from the refrigerant gas by the oil separator to the low pressure portion from the discharge passage;
Liquid refrigerant that has passed through the expansion valve and before flowing into the evaporator is introduced, the oil in the oil return passage can be cooled by the liquid refrigerant, and the liquid refrigerant can be supplied to the suction chamber And an oil cooling section configured to be capable of cooling the refrigerant gas in the suction chamber.   The oil cooling section connects a liquid refrigerant jacket provided on the oil return passage, a downstream area of the expansion valve, and the liquid refrigerant jacket, and introduces a liquid refrigerant into the liquid refrigerant jacket. And a liquid refrigerant supply passage for connecting the liquid refrigerant jacket and the suction chamber and supplying the liquid refrigerant to the suction chamber.   The compressor is a variable capacity compressor capable of changing a discharge capacity by adjusting a pressure of a crank chamber in the housing, and the oil return passage is also connected to the crank chamber as the low pressure portion. The refrigerant circuit according to claim 2.   The oil cooling section is formed from the oil return passage, a liquid refrigerant introduction passage connecting the downstream area of the expansion valve and the oil return passage, and introducing the liquid refrigerant into the oil return passage. Item 4. The refrigerant circuit according to Item 1.   The refrigerant circulation circuit according to any one of claims 2 to 4, wherein the liquid refrigerant introduction passage is provided with a flow rate adjusting valve for adjusting an opening degree of the liquid refrigerant introduction passage.

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