JP2010169337A - Refrigerating cycle device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the reliability of a refrigerating cycle device by providing a first compressor and a second compressor having different structures. <P>SOLUTION: The refrigerating cycle device 100 includes the first compressor 101, the second compressor 102, a radiator 4, an evaporator 6 and a high pressure refrigerant route 50. The first compressor 101 includes a first compression mechanism 1 and an expansion mechanism 5, and the first compression mechanism 1 and the expansion mechanism 5 are connected by a shaft 23. A second compression mechanism 2 of the second compressor 102 is arranged in a refrigerant circuit in parallel with the first compression mechanism 1. The high pressure refrigerant route 50 includes a common route 52 and a communication route 54. A refrigerant compressed by the second compression mechanism 2 is guided to an inner space of a first closed container 10 via the communication route 54 and merged with a refrigerant compressed by the first compression mechanism 1. The merged refrigerants are made to flow in the common route 52, and guided to the radiator 4. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a refrigeration cycle apparatus.

  In recent years, a refrigeration cycle apparatus using a positive displacement expander instead of an expansion valve has been proposed as means for improving the efficiency of the refrigeration cycle apparatus. In the process of expanding the working fluid (refrigerant), the pressure energy is recovered in the form of power by the expander, and the recovered power is used to drive the compressor, thereby reducing power consumption. In such a refrigeration cycle apparatus, a compressor (an expander-integrated compressor) having a structure in which a compression mechanism, an electric motor, and an expansion mechanism are connected by a shaft is used.

According to such a compressor, since the compression mechanism and the expansion mechanism are connected by the shaft, the ratio of the refrigerant density ρ _{e at} the inlet of the expansion mechanism to the refrigerant density ρ _{c at} the inlet of the compression mechanism (ρ _e / Ρ _c ) is always constant (constant of constant density ratio). Therefore, efficient operation cannot be performed under conditions deviating from ideal design conditions.

  In response to this problem, as shown in FIG. 10, a refrigeration cycle apparatus including a first compressor 230 and a second compressor 240 has been proposed (Patent Document 1). The first compressor 230 includes a first compression mechanism 210, an electric motor 211, and an expansion mechanism 212 that are connected to each other by a shaft. The second compressor 240 includes an electric motor 220 and a second compression mechanism 221. In the refrigerant circuit, the first compression mechanism 210 and the second compression mechanism 221 are arranged in parallel. According to this refrigeration cycle apparatus, the restriction of a constant density ratio can be avoided by controlling the rotation speed of each compressor, so that the COP (coefficient of performance) can always be kept high.

  On the other hand, in order to increase the output of the refrigeration cycle apparatus, a refrigeration cycle apparatus using a plurality of compressors is known. For example, Patent Document 2 discloses a refrigeration cycle apparatus shown in FIG. In this refrigeration cycle apparatus, two compressors 320 and 330 are arranged in parallel. Inside the compressors 320 and 330, oil used for lubricating and sealing sliding portions of the compressors is stored. When the balance of the oil holding amount of the compressors 320 and 330 is lost, there is a problem in terms of reliability and efficiency. Therefore, a structure that balances the oil holding amount of the compressors 320 and 330 is employed.

  That is, an oil separator 311 is provided on the discharge side of the compressor 320, and an oil bypass pipe 312 that connects the oil separator 311 and the suction pipe of the compressor 320 is provided. A similar oil separator 311 and oil bypass pipe 312 are also provided on the compressor 330 side. As shown in FIG. 12, an oil leveling pipe 350 is provided at the lower part of the compressors 320 and 330, and oil can be distributed between the compressors 320 and 330 through the oil leveling pipe 350.

  Further, when the two compressors 320 and 330 are operated, the following operation is performed as the oil leveling operation.

  The operating frequency of one compressor 320 is first stepped up by a certain value, and the operating frequency of the other compressor 330 is lowered so that the detected pressure Pd of the pressure sensor 315 does not change until the set time ta elapses. . When the set time ta elapses, the operation frequency of one compressor 320 is stepped down by a certain value, and the other compressor is kept so that the detected pressure Pd of the pressure sensor 315 does not change until the set time ta elapses. Increase 330 operating frequency. Thus, when the set time ta elapses again, the operating frequencies of the compressors 320 and 330 are restored. Each time the set time tb elapses, the above-described step-up and step-down oil equalization operations are repeated.

As described above, the compressors 320 and 330 are connected to each other by the oil equalizing pipe 350, and when the two compressors 320 and 330 are operated, the operation frequency of the compressors 320 and 330 is alternately increased and decreased, The oil of 330 is efficiently distributed through the oil equalizing pipe 350, and the balance of the oil holding amount of both the compressors 320 and 330 is maintained.
Japanese Patent Laid-Open No. 2004-212006 Japanese Patent Laid-Open No. 1-127865

  The problem that the balance of the oil retention amount is lost also exists in the refrigeration cycle apparatus shown in FIG. However, even if an oil equalizing pipe that connects the first compressor 230 and the second compressor 240 is provided, a sufficient oil equalizing effect is not always obtained. This is because the internal pressure of the first compressor 230 and the internal pressure of the second compressor 240 do not always coincide with each other, and in this case, the difference in internal pressure affects the oil level.

  Although the above-described oil leveling operation may be applied to the refrigeration cycle apparatus of FIG. 10, it is also difficult. This is because the first compressor 230 is provided with not only the compression mechanism 210 but also the expansion mechanism 212, and the amount of oil used in the first compressor 230 and the amount of oil used in the second compressor 240 are the same. It is not limited. In addition, there is a problem that it is difficult to achieve both the oil leveling operation that involves raising and lowering the operation frequency and the high-efficiency operation that controls the operation frequency of the first compressor 230 and the second compressor 240 so that the COP is maximized.

  This invention is made | formed in view of this point, and it aims at improving the reliability of the refrigerating-cycle apparatus provided with the 1st compressor and 2nd compressor of a mutually different structure, without sacrificing efficiency. And

That is, the present invention
A first compression mechanism, an expansion mechanism, a shaft connecting the first compression mechanism and the expansion mechanism, the first compression mechanism, the expansion mechanism, and the shaft; A first compressor having a first sealed container whose internal space is filled with a compressed refrigerant;
A second compressor having a second compression mechanism disposed in parallel with the first compression mechanism in the refrigerant circuit; and a second hermetic container for housing the second compression mechanism;
A radiator that cools the refrigerant compressed by the first compression mechanism and the refrigerant compressed by the second compression mechanism;
An evaporator for evaporating the refrigerant expanded by the expansion mechanism;
A path for guiding the refrigerant compressed by the first compression mechanism and the refrigerant compressed by the second compression mechanism to the radiator, a common path connecting the first sealed container and the radiator, A communication path that connects the second sealed container and the first sealed container so that the refrigerant compressed by the second compression mechanism is guided to the radiator via the internal space of the first sealed container. Having a high pressure refrigerant path;
A refrigeration cycle apparatus is provided.

  The oil mixed with the refrigerant in the first compression mechanism and the second compression mechanism is discharged together with the compressed refrigerant into the internal spaces of the first closed container and the second closed container, and is separated from the refrigerant in the internal spaces. The separated oil returns to the oil reservoir at the bottom of the first sealed container or the second sealed container. On the other hand, the oil mixed with the refrigerant by the expansion mechanism flows out into the refrigerant circuit together with the refrigerant. That is, in the refrigeration cycle apparatus including the first compressor (expander-integrated compressor) and the second compressor, the amount of oil that normally flows from the first compressor to the refrigerant circuit is reduced from the second compressor to the refrigerant. More than the amount of oil that flows into the circuit. Accordingly, the oil retention amount of the first compressor gradually decreases, and the oil retention amount of the second compressor gradually increases.

  According to the refrigeration cycle apparatus of the present invention, the refrigerant compressed by the second compression mechanism is guided to the first sealed container through the communication path, and flows to the radiator via the internal space of the first sealed container. That is, a main path (path with the highest flow rate) for guiding the refrigerant compressed by the second compression mechanism to the radiator is formed in the internal space of the first sealed container. The refrigerant compressed by the first compression mechanism also flows to the radiator via the internal space of the first sealed container. In the first sealed container, oil can be separated from both the refrigerant compressed by the first compression mechanism and the refrigerant compressed by the second compression mechanism. This prevents a decrease in the oil retention amount of the first compressor and an increase in the oil retention amount of the second compressor. Lubrication failure in the first compressor due to oil shortage and load increase in the second compressor due to excessive oil can be prevented, and a highly efficient and reliable refrigeration cycle apparatus can be provided.

(First embodiment)
As shown in FIG. 1, the refrigeration cycle apparatus 100 of the present embodiment includes a first compressor 101 (expander-integrated compressor), a second compressor 102, a radiator 4, an evaporator 6, and these devices. A plurality of pipes 3a to 3d that are connected to each other to form a refrigerant circuit are provided. In the refrigerant circuit, the first compression mechanism 1 and the second compression mechanism 2 are arranged in parallel to each other. The refrigerant circuit is filled with a refrigerant such as carbon dioxide or hydrofluorocarbon.

  The first compressor 101 includes a first compression mechanism 1 that compresses refrigerant, an expansion mechanism 5 that expands refrigerant, a shaft 23 that connects the first compression mechanism 1 and the expansion mechanism 5, and a first that drives the shaft 23. An electric motor 11, an oil pump 15 that supplies oil to the first compression mechanism 1, and a first sealed container 9 that houses them are provided. A first suction pipe 7, a first discharge pipe 19, an expansion side suction pipe 21, an expansion side discharge pipe 22 and an introduction pipe 49 are attached to the first sealed container 9. A first oil reservoir 13 is formed at the bottom of the first sealed container 9.

  The second compressor 102 includes a second compression mechanism 2 that compresses refrigerant, a shaft 24 connected to the second compression mechanism 2, a second electric motor 12 that drives the shaft 24, and oil that supplies oil to the second compression mechanism 2. The pump 16 and the 2nd airtight container 10 which accommodates these are provided. A second suction pipe 8 and a second discharge pipe 20 are attached to the second sealed container 10. A second oil reservoir 14 is formed at the bottom of the second sealed container 10.

  The first discharge pipe 19 is connected to the radiator 4 through the first pipe 3a. The radiator 4 is connected to the expansion side suction pipe 21 via the second pipe 3b. The expansion side discharge pipe 22 is connected to the evaporator 6 via the third pipe 3c. The evaporator 6 is connected to the first suction pipe 7 and the second suction pipe 8 via the fourth pipe 3d. The end of the fourth pipe 3d opposite to the side connected to the evaporator 6 is bifurcated, and the divided parts are connected to the first suction pipe 7 and the second suction pipe 8, respectively. Yes.

  The refrigeration cycle apparatus 100 further includes a communication pipe 48 that connects the second discharge pipe 20 of the second compressor 102 and the introduction pipe 49 of the first compressor 101. The refrigerant compressed by the second compression mechanism 2 includes the internal space of the second sealed container 10, the second discharge pipe 20, the communication pipe 48, the introduction pipe 49, the internal space of the first sealed container 9, the first discharge pipe 19 and The first pipe 3a flows toward the radiator 4 in this order. As described above, the refrigeration cycle apparatus 100 includes the high-pressure refrigerant path 50 that guides the refrigerant compressed by the first compression mechanism 1 and the refrigerant compressed by the second compression mechanism 2 to the radiator 4. 50, the common path 52 connecting the first sealed container 9 and the radiator 4, and the refrigerant compressed by the second compression mechanism 2 is guided to the radiator 4 through the internal space of the first sealed container 9. A communication path 54 that allows the second sealed container 10 and the first sealed container 9 to communicate with each other is provided. Specifically, the common path 52 is formed by the first discharge pipe 19 and the first pipe 3 a, and the communication path 54 is formed by the second discharge pipe 20, the communication pipe 48, and the introduction pipe 49.

  Oil that has flowed into the first sealed container 9 together with the refrigerant compressed by the second compression mechanism 2 can be separated from the refrigerant in the internal space of the first sealed container 9. Since the first compressor 101 includes the expansion mechanism 5 in addition to the first compression mechanism 1, the amount of oil used in the first compressor 101 is larger than that in the second compressor 102, but the first compression Since the amount of oil returned to the machine 101 is also large, the balance of the oil holding amounts of the first compressor 101 and the second compressor 102 is maintained. Therefore, the shortage of oil in the first compressor 101 and the occurrence of excessive oil in the second compressor 102 can be prevented.

  The refrigerant compressed by the first compression mechanism 1 and the refrigerant compressed by the second compression mechanism 2 merge in the internal space of the first sealed container 9. The compressed refrigerant flows through the first discharge pipe 19 and the first pipe 3 a, radiates heat with the radiator 4, and then is guided to the expansion mechanism 5. The refrigerant expands in the expansion mechanism 5, and the expansion mechanism 5 recovers power from the expanding refrigerant. Thereafter, the refrigerant absorbs heat in the evaporator 6 and is guided to the first compression mechanism 1 and the second compression mechanism 2 through the fourth pipe 3d.

  During operation of the refrigeration cycle apparatus 100, the pressure at the inlet of the communication path 54 is higher than the pressure at the outlet of the communication path 54. Specifically, the refrigerant pressure in the second discharge pipe 20 is higher than the refrigerant pressure in the introduction pipe 49. This is because the refrigerant compressed by the second compression mechanism 2 flows in the direction from the second sealed container 10 to the first sealed container 9 through the communication path 54. The pressure difference between the inlet and the outlet is equal to the pressure loss in the communication path 54.

  During the operation of the refrigeration cycle apparatus 100, the internal space of the first sealed container 9 is filled with the refrigerant compressed by the first compression mechanism 1 and the refrigerant compressed by the second compression mechanism 2. The internal space of the second sealed container 10 is also filled with the refrigerant compressed by the second compression mechanism 2. That is, the first compressor 101 and the second compressor 102 are so-called high pressure shell types. According to the high-pressure shell type, there is an effect of improving COP by adding heat of the electric motor to the refrigerant. In addition, since the first compressor 101 and the second compressor 102 are high-pressure shell types, the second compression can be achieved simply by communicating the internal space of the second sealed container 10 and the internal space of the first sealed container 9 through the communication path 54. The refrigerant compressed by the mechanism 2 can be guided to the internal space of the first sealed container 9. However, a configuration in which the compressed refrigerant flows directly from the second compression mechanism 2 into the internal space of the first sealed container 9 is also conceivable.

  In the present embodiment, the entire amount of the refrigerant compressed by the second compression mechanism 2 can be led to the radiator 4 by flowing through the communication path 54. The total amount of the refrigerant compressed by the second compression mechanism 2 flows into the first sealed container 9 because all the oil that has not been separated from the refrigerant in the internal space of the second sealed container 10 is inside the first sealed container 9. Means flowing into the space. Accordingly, an appropriate amount of oil can move from the second compressor 102 to the first compressor 101.

  The second sealed container 10 is not provided with a compressed refrigerant outlet other than the second discharge pipe 20. Therefore, the refrigerant compressed by the second compression mechanism 2 flows only in the direction from the second sealed container 10 to the first sealed container 9 through the communication path 54. Thereby, the movement of the oil from the 1st compressor 101 to the 2nd compressor 102 can be prevented. A backflow prevention valve may be provided in the communication path 54.

  The flow path area of the common path 52 and the flow path area of the communication path 54 may be the same or different. For example, if the same refrigerant pipe is used for the second discharge pipe 20, the communication pipe 48, the introduction pipe 49, the first discharge pipe 19, and the pipes 3a to 3d, cost can be saved.

<< First compressor >>
Next, the first compressor 101 will be described in detail with reference to FIG.

  The first sealed container 9 has a cylindrical shape with its upper end and lower end closed. A first oil reservoir 13 is formed at the bottom of the first sealed container 9 by collecting oil. The internal space above the first oil reservoir 13 of the first sealed container 9 is filled with the compressed refrigerant. The expansion mechanism 5 is disposed at a lower position in the first sealed container 9 and is immersed in the first oil reservoir 13. The first compression mechanism 1 is disposed at an upper position in the first sealed container 9. The axial direction of the first shaft 23 is parallel to the vertical direction. In the 1st airtight container 9, the 1st compression mechanism 1, the 1st electric motor 11, the 1st suppression board (1st suppression member) 17, the 1st oil pump 15, the heat insulation member 37, and the expansion mechanism 5 are this order from the top. Are lined up.

  Inside the first shaft 23, a first oil supply path 23 c that extends upward from the first oil reservoir 13 and guides oil from the first oil pump 15 to the first compression mechanism 1 is formed. More specifically, the first shaft 23 includes an upper shaft 23 a and a lower shaft 23 b, and these shafts 23 a and 23 b are connected to each other by a connecting member 26 at a position slightly below the first suppression plate 17. ing. The first oil supply path 23c penetrates the upper shaft 23a in the axial direction, extends downward from the upper end surface of the lower shaft 23b, and opens on the side surface of the lower shaft 23b. Further, an expansion mechanism side oil supply passage 23e that guides oil from the lower end surface of the lower shaft 23b to each sliding portion of the expansion mechanism 5 is formed inside the lower shaft 23b.

  The first compression mechanism 1 is fixed to the inner peripheral surface of the first sealed container 9 by welding or the like. In the present embodiment, the first compression mechanism 1 is of a scroll type. However, the type of the first compression mechanism 1 is not limited, and for example, a rotary compressor can be used.

  More specifically, the first compression mechanism 1 includes a fixed scroll 51, a movable scroll 52 that faces the fixed scroll 51 in the axial direction, and a bearing member 53 that supports the upper portion of the upper shaft 23a. Each of the fixed scroll 51 and the movable scroll 52 has spiral-shaped (for example, involute-shaped) wraps 51a and 52a that mesh with each other. A spiral compression chamber 58 is formed between the wrap 51a and the wrap 52a. A discharge hole 51 b that is opened and closed by a reed valve 64 is provided at the center of the fixed scroll 51. An Oldham ring 60 that prevents the rotation of the movable scroll 52 is disposed below the movable scroll 52. An eccentric portion is formed at the upper end portion of the upper shaft 23a, and the movable scroll 52 is fitted to the eccentric portion. The movable scroll 52 turns in a state of being eccentric from the axis of the upper shaft 23a. The movable scroll 52 is provided with an oil distribution path 52b that guides the oil supplied from the first oil supply path 23c to each sliding portion.

  A cover 62 is provided on the upper side of the fixed scroll 51. In the fixed scroll 51 and the bearing member 53, a flow path 61 is formed at a position covered by the cover 62 so as to penetrate up and down. Further, the fixed scroll 51 and the bearing member 53 are formed with a flow path 63 penetrating them vertically at positions outside the cover 62. The refrigerant compressed in the compression chamber 58 is discharged from the discharge hole 51 b to the space surrounded by the cover 62, then discharged to the lower side of the first compression mechanism 1 through the flow path 61, and further through the flow path 63. 1 Leaded to the upper side of the compression mechanism 1.

  The first suction pipe 7 passes through the side portion of the first sealed container 9 and is connected to the fixed scroll 51. Thereby, the first suction pipe 7 is connected to the suction side of the first compression mechanism 1. The first discharge pipe 19 passes through the upper part of the first sealed container 9, and the lower end of the first discharge pipe 19 opens into the space above the first compression mechanism 1 in the first sealed container 9. .

  The 1st electric motor 11 is comprised from the rotor 11a fixed to the middle part of the upper side shaft 23a, and the stator 11b arrange | positioned at the outer peripheral side of the rotor 11a. The stator 11 b is fixed to the inner peripheral surface of the first sealed container 9. The stator 11b is connected to a terminal 66 through a motor wiring 65. A space G through which refrigerant can flow is formed between the rotor 11a and the stator 11b. A space H through which the refrigerant can flow is also formed between the stator 11 b and the first closed container 9. The first compression mechanism 1 is driven by rotating the upper shaft 23 a by the first electric motor 11.

  The first suppression plate 17 is disposed at a position slightly above the first oil reservoir 13 (when operation is stopped), and the first compression mechanism 1 extends through the internal space of the first sealed container 9 along the axial direction of the shaft 23. And it partitions into the upper side space where the 1st electric motor 11 is arrange | positioned, and the lower side space where the expansion mechanism 5 is arrange | positioned. In the present embodiment, the first restraining plate 17 has a disk shape having a diameter substantially the same as the inner diameter of the first sealed container 9, and the peripheral edge thereof is on the inner peripheral surface of the first sealed container 9. It is fixed by welding or the like. The first suppression plate 17 suppresses the flow of oil stored at the bottom of the first sealed container 9.

  A plurality of through holes 17a are provided in the peripheral edge portion of the first suppression plate 17, and an oil return path is formed by these through holes 17a for flowing oil from the upper space to the lower space. A through hole 17 b is provided at the center of the first suppression plate 17. A bearing member 42 that supports the lower portion of the upper shaft 23a is attached to the lower surface of the first suppression plate 17 so as to be fitted into the through hole 17b. The oil pump 15, the heat insulating member 37, the expansion mechanism 5, and the like are fixed to the first sealed container 9 via the first suppression plate 17. However, the heat insulating member 37 and the expansion mechanism 5 may be directly fixed to the first sealed container 9.

  The bearing member 42 is provided with a storage chamber 43 that stores the coupling member 26. Further, an intermediate member 41 is disposed below the bearing member 42 in the vertical direction with a predetermined cross-sectional shape, and the lower shaft 23b passes through the center thereof. The intermediate member 41 closes the storage chamber 43. Has been.

  The first oil pump 15 is sandwiched between the intermediate member 41 and the heat insulating member 37. In the present embodiment, the first oil pump 15 is a rotary type. However, the type of the first oil pump 15 is not limited and, for example, a trochoid gear pump can be used.

  Specifically, the first oil pump 15 includes a piston 40 that is fitted into an eccentric portion formed on the lower shaft 23 b and moves eccentrically, and a housing (cylinder) 39 that accommodates the piston 40. . A crescent-shaped working chamber 15 b is formed between the piston 40 and the housing 39. The working chamber 15b is closed with an intermediate member 41 from the upper side and closed with a heat insulating member 37 from the lower side. The housing 39 is formed with a first oil suction port 15a that allows the first oil reservoir 13 and the working chamber 15b to communicate with each other. The intermediate member 41 is formed with a guide path 41a that guides the oil discharged from the oil pump 15 to the inlet of the first oil supply path 23c. For this reason, when the first shaft 23 rotates, the oil in the first oil reservoir 13 is sucked from the first oil suction port 15a by the first oil pump 15 and then discharged to the guide path 41a. 1 is supplied to the first compression mechanism 1 through the oil supply passage 23c.

  The heat insulating member 37 divides the first oil reservoir 13 into an upper layer portion 13a and a lower layer portion 13b and regulates the oil flow between the upper layer portion 13a and the lower layer portion 13b. In the present embodiment, the heat insulating member 37 has a disk shape having a diameter slightly smaller than the inner diameter of the first sealed container 9, and is formed between the heat insulating member 37 and the inner peripheral surface of the first sealed container 9. The oil flow is slightly allowed through the created gap. The lower shaft 23 b passes through the center of the heat insulating member 37.

  The expansion mechanism 5 is installed below the heat insulating member 37 with a spacer 38 therebetween. The spacer 38 forms a space filled with oil in the lower layer portion 13 b between the heat insulating member 37 and the expansion mechanism 5. The oil that fills the space secured by the spacer 38 itself acts as a heat insulating material and forms a temperature stratification in the axial direction.

  In the present embodiment, the expansion mechanism 5 is a two-stage rotary type. However, the type of the expansion mechanism 5 is not limited, and other types of positive displacement expanders such as a single-stage rotary expander and a scroll expander can be used.

  More specifically, the expansion mechanism 5 includes a closing member 36, a lower bearing member 27, a first expansion portion 28a, an intermediate plate 30, a second expansion portion 28b, and an upper bearing member 29, which are arranged from the bottom to the top. It is arranged in this order. The thickness of the 2nd expansion part 28b is larger than the 1st expansion part 28a. In the present embodiment, the expansion side suction pipe 21 and the expansion side discharge pipe 22 penetrate the side portion of the first sealed container 9 and are directly connected to the upper bearing member 29.

  As shown in FIG. 3A, the first expansion portion 28a includes a ring-shaped piston 32a that fits in an eccentric portion formed on the lower shaft 23b, and a cylinder 31a that accommodates the piston 32a. A first fluid chamber 33a is formed between the inner peripheral surface of the cylinder 31a and the outer peripheral surface of the piston 32a. A vane groove 34c extending radially outward is formed in the cylinder 31a, and the vane 34a is slidably disposed in the vane groove 34c. A back chamber 34h that communicates with the vane groove 34c and extends outward in the radial direction is formed on the back side (radially outward) of the vane 34a of the cylinder 31a. A spring 35a for urging the vane 34a toward the piston 32a is provided in the back chamber 34h. The vane 34a partitions the first fluid chamber 33a into a high pressure side fluid chamber VH1 and a low pressure side fluid chamber VL1.

  As shown in FIG. 3B, the second expansion portion 28b includes a ring-shaped piston 32b that fits into an eccentric portion formed on the lower shaft 23b, and a cylinder 31b that accommodates the piston 32b. A second fluid chamber 33b is formed between the inner peripheral surface of the cylinder 31b and the outer peripheral surface of the piston 32b. A vane groove 34d extending radially outward is also formed in the cylinder 31b, and the vane 34b is slidably disposed in the vane groove 34d. A back chamber 34i that communicates with the vane groove 34d and extends radially outward is formed on the back side of the vane 34b of the cylinder 31b. A spring 35b that urges the vane 34b toward the piston 32b is provided in the back chamber 34i. The vane 34b partitions the second fluid chamber 33b into a high pressure side fluid chamber VH2 and a low pressure side fluid chamber VL2.

  As shown in FIG. 2, the lower bearing member 27 supports the lower shaft 23b and closes the first fluid chamber 33a from the lower side. On the lower surface of the lower bearing member 27, a pre-expansion fluid chamber 27 b communicating with the expansion side suction pipe 21 through the refrigerant introduction path 31 c is provided, and the pre-expansion fluid chamber 27 b is closed with a closing member 36. Further, the lower bearing member 27 is provided with a suction port 27a through which refrigerant flows from the pre-expansion fluid chamber 27b to the high-pressure side fluid chamber VH1 of the first expansion portion 28a.

  The intermediate plate 30 closes the first fluid chamber 33a (FIG. 3A) from above, and closes the second fluid chamber 33b (FIG. 3A) from below. Further, the intermediate plate 30 is formed with a communication passage 30a that constitutes an expansion chamber by communicating the low pressure side fluid chamber VL1 of the first expansion portion 28a and the high pressure side fluid chamber VH2 of the second expansion portion 28b.

  The upper bearing member 29 supports the lower shaft 23b and closes the second fluid chamber 33b from the upper side. Further, the upper bearing member 29 is provided with a discharge port 29a through which the refrigerant is led out from the low pressure side fluid chamber VL2 of the second expansion portion 28b to the expansion side discharge pipe 22.

  The oil in the upper layer portion 13a of the first oil reservoir 13 is supplied to the first compression mechanism 1 by the first oil pump 15 through the first oil supply passage 23c. Further, the oil supplied to the first compression mechanism 1 is used for sealing and lubrication between components. A part of the oil is discharged together with the refrigerant into the inner space of the first hermetic container 9 through the flow path 61, and the remaining part flows down to the upper end of the rotor 11a while lubricating the bearing member 53 and the upper shaft 23a. The oil and the compressed refrigerant discharged to the lower side of the first compression mechanism 1 proceed downward in the space G in the first electric motor 11, wrap around the lower end of the first electric motor 11, and the first electric motor 11 and the first hermetic seal. The clearance H with the container 9 is advanced upward. In this process, the refrigerant and the oil are separated by gravity and centrifugal force. The oil separated from the refrigerant returns to the first oil reservoir 13 through the through hole 17a of the first suppression plate 17.

  The supply of oil to the expansion mechanism 5 is performed through an expansion mechanism side oil supply path 23e provided in the lower shaft 23b. The oil supplied to the expansion mechanism 5 is used for sealing and lubrication between parts. At this time, part of the oil flows into the first fluid chamber 33a and the second fluid chamber 33b through the gaps around the pistons 32a and 32b and the vanes 34a and 34b. The inflowed oil is discharged from the expansion side discharge pipe 22 to the third pipe 3c.

<< Second compressor >>
Next, the second compressor 102 will be described in detail with reference to FIG.

  The second sealed container 10 has a cylindrical shape in which the upper end and the lower end are closed. In the present embodiment, the inner diameter of the second sealed container 10 is the same as the inner diameter of the first sealed container 9. A second oil reservoir 14 is formed at the bottom of the second sealed container 10 by collecting oil. The internal space above the second oil reservoir 14 of the second sealed container 10 is filled with the refrigerant discharged from the second compression mechanism 2. In the second sealed container 10, the second compression mechanism 2, the second electric motor 12, the second suppression plate (second suppression member) 18, and the second oil pump 16 are arranged in this order from top to bottom. Yes.

  The second shaft 24 connects both the second compression mechanism 2 and the second electric motor 12 so that they are aligned in the vertical direction. The second shaft 24 extends in the vertical direction across the second compression mechanism 2 and the second oil pump 16. Inside the second shaft 24, a second oil supply path 24 a that penetrates the second shaft 24 in the axial direction and guides oil from the second oil pump 16 to the second compression mechanism 2 is formed.

  In the present embodiment, as the second compression mechanism 2, the same scroll type compression mechanism as that of the first compression mechanism 1 is used. Therefore, regarding the configuration of the second compression mechanism 2, the same members as those of the first compression mechanism 1 are denoted by the same reference numerals, and the description thereof is omitted. The second electric motor 12 is also the same as the first electric motor 11, and the rotor 12a and the stator 12b of the second electric motor 12 correspond to the rotor 11a and the stator 11b of the first electric motor 11, respectively.

  The second suppression plate 18 is disposed at a position slightly above the second oil reservoir 14 (when operation is stopped), and the second compression mechanism 2 and the second compression chamber 2 along the vertical direction in the internal space of the second hermetic container 10. It is partitioned into an upper space in which the electric motor 12 is arranged and a lower space in which oil is stored. The second suppression plate 18 has a disk shape having a diameter substantially the same as the inner diameter of the second sealed container 10, and the peripheral edge thereof is fixed to the inner peripheral surface of the second sealed container 10 by welding or the like. ing. The flow of the oil accumulated at the bottom of the second sealed container 10 is suppressed by the second suppression plate 18.

  A plurality of through holes 18a are provided in the peripheral portion of the second suppression plate 18, and an oil return path is configured by these through holes 18a. A through hole 18 b is provided at the center of the second suppression plate 18. A bearing member 44 that supports the lower portion of the second shaft 24 is attached to the lower surface of the second suppression plate 18 so as to be fitted into the through hole 18b.

  The second oil pump 16 includes an oil gear pump 45 and an oil path plate 46. The oil gear pump 45 is disposed in a recess 44 a provided on the lower surface of the bearing member 44, and is attached to the lower end portion of the second shaft 24. The oil path plate 46 is attached to the bearing member 44 so as to close the recess 44a. The oil passage plate 46 has a suction passage 46a that passes through the oil passage plate 46 to introduce oil into the working chamber of the oil gear pump 45, and a discharge that guides oil from the working chamber of the oil gear pump 45 to the second oil supply passage 24a. A path 46b is formed.

  A funnel-shaped oil strainer 47 is disposed below the oil passage plate 46, and the second oil suction port 16 a is configured by the inlet of the oil strainer 47. The oil strainer 47 can be omitted. In this case, the lower end of the suction passage 46a of the oil passage plate 46 constitutes the second oil suction port 16a. Further, the type of the second oil pump 16 is not limited at all, and for example, a rotary pump similar to the first oil pump 15 can be used.

  When the second shaft 24 rotates, the oil in the second oil reservoir 14 is sucked from the second oil suction port 16a by the second oil pump 16 and then discharged to the second oil supply path 24a, so that the second oil supply path It is supplied to the second compression mechanism 2 through 24a. The oil supplied to the second compression mechanism 2 then follows the same path as described with respect to the first compression mechanism 1 and returns to the second oil reservoir 14. A part of the oil is discharged together with the compressed refrigerant from the second discharge pipe 20 to the outside of the second sealed container 10 and guided to the first sealed container 9.

  As shown in FIG. 1, in the first sealed container 9, the inlet of the first discharge pipe 19 (common path 52) is located above the first motor 11, and the outlet of the introduction pipe 49 (communication path 54). Is located below the first electric motor 11. According to such a positional relationship, the refrigerant guided to the internal space of the first sealed container 9 through the introduction pipe 49 flows toward the common path 52 against the gravity. Therefore, the effect | action which isolate | separates oil from a refrigerant | coolant works effectively, and the quantity of the oil which flows out outside the 1st airtight container 9 through the 1st discharge pipe 19 decreases.

  Specifically, as shown in FIG. 2, the refrigerant guided to the internal space of the first sealed container 9 through the introduction pipe 49 (communication path 54) vertically passes through the space H and the flow path 63 around the first motor 11. Advancing in the direction reaches the inlet of the first discharge pipe 19 (common path 52). That is, the flow path from the outlet of the introduction pipe 49 to the inlet of the first discharge pipe 19 is formed by the space H around the first electric motor 11 and the flow path 63.

  Specifically, the refrigerant compressed by the first compression mechanism 1 passes through the first electric motor 11 and is guided to the space below the first electric motor 11 and is compressed by the second compression mechanism 2 in that space. The refrigerant and the refrigerant compressed by the first compression mechanism 1 merge, and then proceed upward in the space H and the flow path 63 around the first electric motor 11 and enter the first discharge pipe 19 (common path 52). To. By forming such a flow in the first sealed container 9, the refrigerant and the oil can be sufficiently separated in the internal space of the first sealed container 9.

  The pressure of the refrigerant guided to the first sealed container 9 through the introduction pipe 49 is slightly lower than the pressure immediately after compression due to the effect of pressure loss. Similarly, the pressure of the refrigerant compressed by the first compression mechanism 1 also slightly decreases in the process of proceeding to the lower side of the first electric motor 11. When reaching the lower side of the first electric motor 11, the pressure of the refrigerant compressed by the first compression mechanism 1 approaches the pressure of the refrigerant guided to the first sealed container 9 through the introduction pipe 49. Since the pressure difference between the refrigerants is small, the refrigerant can be smoothly introduced into the first sealed container 9 from the introduction pipe 49.

  In the present embodiment, a partition wall 67 that guides the refrigerant compressed by the first compression mechanism 1 into the first motor 11 (space G) is provided between the first compression mechanism 1 and the first motor 11. . The partition wall 67 has a cylindrical shape, extends downward from the lower surface of the bearing member 53 of the first compression mechanism 1, and reaches the upper end of the stator 11 b of the first electric motor 11. The channel 61 opens into a space surrounded by the partition wall 67. Accordingly, the refrigerant compressed by the first compression mechanism 1 can be smoothly guided into the first electric motor 11.

  In the present embodiment, the outlet of the introduction pipe 49 (communication path) is located between the first electric motor 11 and the first suppression plate 17 (suppression member) with respect to the vertical direction. According to such an arrangement, the operation of connecting the introduction pipe 49 to the first sealed container 9 is easy, and there is also room for providing the introduction pipe 49. Further, since the outlet of the introduction pipe 49 is located above the first suppression plate 17, the oil in the first oil reservoir 13 is agitated by the refrigerant guided to the first sealed container 9 through the introduction pipe 49. Can be prevented. That is, oil can be prevented from being mixed with the refrigerant.

  However, the position of the introduction pipe 49 is not limited as long as the compressed refrigerant from the first compressor 102 can be smoothly introduced into the first sealed container 9. For example, as shown in FIG. 7, the outlet of the introduction pipe 49 may be located in the vicinity of the discharge hole 51 b of the first compression mechanism 1. According to the example of FIG. 7, the outlet of the introduction pipe 49 is located in the space surrounded by the cover 62. Since the discharge hole 51b of the first compression mechanism 1 is opened in the space surrounded by the cover 62, the refrigerant compressed by the first compression mechanism 1 and the refrigerant compressed by the second compression mechanism 2 in this space. And join. After the merge, the compressed refrigerant flows through the flow path 61, the space G, the space H, and the flow path 63 in this order, and reaches the first discharge pipe 19. Therefore, the compressed refrigerant from the introduction pipe 49 moves in the first sealed container 9 for a long distance. As a result, oil can be more reliably separated from the refrigerant. In order to obtain the same effect, the outlet of the introduction pipe 49 may be located in a space surrounded by the partition wall 67.

  According to the present embodiment, the first compressor 101 includes an oil pump 15 for supplying the oil stored in the bottom of the first sealed container 9 to the first compression mechanism 1, and the first compression mechanism 1 and the expansion mechanism 5. Between. The first shaft 23 is formed with an oil supply passage 23 c extending in the axial direction so that the oil discharged from the oil pump 15 is guided to the first compression mechanism 1. Therefore, the relatively high temperature oil that has flowed into the first sealed container 9 through the introduction pipe 49 is preferentially supplied to the first compression mechanism 1 by the oil pump 15. This is preferable from the viewpoint of preventing the temperature of the compressed refrigerant from being lowered by supplying low-temperature oil to the first compression mechanism 1.

  More specifically, the axial direction of the first shaft 23 is parallel to the vertical direction, and the first compression mechanism 1 is disposed on the upper side and the expansion mechanism 5 is disposed on the lower side in the first sealed container 9. An oil pump 15 is disposed between the first suppression plate 17 and the expansion mechanism 5, and oil discharged from the oil pump 15 is supplied to the first compression mechanism 1 through an oil supply passage 23 c of the shaft 23. Note that the oil pump 15 may be used to supply oil to the expansion mechanism 5.

  Next, the relationship between the oil flow during operation of the refrigeration cycle apparatus 100 and the fluctuations in the oil levels of the first oil reservoir 13 and the second oil reservoir 14 will be described. FIG. 5 shows the oil flow with arrows during operation of the refrigeration cycle apparatus. FIG. 6 shows the change over time in the mass flow rate of oil at a predetermined location in the refrigerant circuit.

As shown in FIG. 5, the mass flow rate of oil returning to the first compressor 101 via the first suction pipe 7 is Fs1, the mass flow rate of oil returning to the second compressor 102 via the second suction pipe 8 is Fs2, and The mass flow rate of oil flowing through the communication path 54 together with the refrigerant compressed by the compression mechanism 2 is Fd2, and the mass flow rate of oil guided to the expansion mechanism 5 through the common path 52 is Fd1. Also, let F _{exp be} the mass flow rate of oil that enters the expansion mechanism 5 from the first oil reservoir 13 and is mixed with the refrigerant. When the mass flow rate of oil discharged from the expansion side discharge pipe 22 is F _Low , the relationship of F _Low = Fd1 + F _exp is established. When the rotation speed of the first compressor 101 and the rotation speed of the second compressor 102 are equal and the suction volume of the first compressor 101 and the suction volume of the second compressor 102 are equal, Fs1 = Fs2 = The relationship of F _Low / 2 is also established.

Next, the change in the oil flow rate from the transient state after the start of operation to the steady state where the oil level is stabilized will be described. FIG. 6 shows an example in which the mass flow rate F _{exp of the} oil mixed with the refrigerant in the expansion mechanism 5 is larger than the mass flow rate Fd1 of the oil flowing out from the first sealed container 9. However, the magnitude relationship of Fd1 and F _exp may also be reversed from the example of FIG.

At the start of operation (t = 0), the mass flow rate Fs2 (= (Fd1 + F _exp ) / 2) of oil flowing into the second sealed container 10 is greater than the mass flow rate Fd2 of oil flowing through the communication path 54. Therefore, the difference (Fs2-Fd2) remains in the second sealed container 10. Thereafter, when time elapses, the oil level S2 of the second oil reservoir 14 increases. As the oil level S2 increases, the space v2 between the oil level S2 and the lower end of the second electric motor 12 becomes narrower. When the space v2 is narrowed, the refrigerant and the oil are hardly separated in the space v2, so that the mass flow rate Fd2 of the oil exiting from the second sealed container 10 together with the refrigerant increases.

On the other hand, in the first closed casing 9, in addition to the oil (mass flow rate Fd1) together with the refrigerant exiting the first closed casing 9, the oil mixed in the refrigerant in the expansion mechanism 5 (mass flow rate F _exp) is present. Therefore, the oil level S1 tends to decrease for a while from the start of operation. However, since the mass flow rate Fd2 of the oil flowing into the first sealed container 9 through the communication path 54 increases with time, the descending speed of the oil level S1 gradually decreases. Note that the mass flow rate F _{exp of the} oil mixed with the refrigerant in the expansion mechanism 5 depends on the rotation speed of the expansion mechanism 5 (= the rotation speed of the first compression mechanism 1), so that the rotation speed of the expansion mechanism 5 is constant. The mass flow rate F _{exp is} also constant. Strictly speaking, the mass flow rate F _exp also depends on the high-low pressure difference of the refrigeration cycle. The mass flow rate F _exp increases as the high / low pressure difference of the refrigeration cycle increases. For example, when the refrigeration cycle apparatus 100 is started up, the mass flow rate F _exp gradually increases because the high-low pressure difference gradually increases. If the cycle is stable, the mass flow rate F _exp becomes constant.

When the time further elapses, the mass flow rate Fs2 of oil flowing into the second sealed container 10 becomes equal to the mass flow rate Fd2 of oil flowing out of the second sealed container 10 (time t1). As a result, the increase in the oil level S2 of the second oil reservoir 14 stops. Thereafter, the steady state is maintained, and the operation is continued while maintaining a stable oil level. Further, when this steady state is viewed from the viewpoint of the first sealed container 9, Fs1 + Fd2 = Fd1 + F _{exp is established} , and the lowering of the oil level S1 of the first oil reservoir 13 is stopped. That is, after a while from the start of operation, the oil levels S1 and S2 are automatically settled at a predetermined position determined according to the specifications of the refrigeration cycle apparatus and the operating conditions (for example, the rotational speed of each compressor).

As described above, according to the present embodiment, the oil (mass flow rate Fd2) that flows out of the imbalance in the oil retention amount caused by the oil (mass flow rate F _exp ) mixed with the refrigerant in the expansion mechanism 5 from the second sealed container 10. ). There is no need to perform a special operation to keep the balance of the oil holding amount.

In the present embodiment, the types of the first compression mechanism 1 and the second compression mechanism 2 are a scroll type, and the type of the expansion mechanism 5 is a rotary type. Generally, the rotary fluid mechanism is more likely to mix oil with the refrigerant than the scroll fluid mechanism. In particular, when the type of the expansion mechanism 5 is a rotary type, since the mass flow rate F _{exp of the} oil mixed with the refrigerant in the expansion mechanism 5 tends to increase, the application of the present invention becomes more important.

  In the present embodiment, a two-stage rotary expansion mechanism is used as the expansion mechanism 5. The two-stage rotary expansion mechanism is more efficient than the single-stage rotary expansion mechanism, but has a large amount of oil usage and tends to cause an imbalance in the amount of oil retained. However, when the present invention is applied, the disadvantages of the two-stage rotary expansion mechanism can be compensated, and high-efficiency power recovery utilizing the advantages of the two-stage rotary can be performed while ensuring high reliability.

  In this embodiment, carbon dioxide is used as the refrigerant. Since carbon dioxide has a higher specific gravity than other chlorofluorocarbon refrigerants, it has a strong action of stirring oil in a sealed container and taking the oil out of the sealed container. Therefore, when a refrigerant having a large specific gravity such as carbon dioxide is used, the application of the present invention becomes more important.

(Second Embodiment)
As shown in FIG. 8, the refrigeration cycle apparatus 104 of the present embodiment is different from the first embodiment in that a path that does not pass through the internal space of the first sealed container 9 is newly provided. Further, an oil equalizing pipe 25 is provided for communicating the first oil reservoir 13 of the first sealed container 9 and the second oil reservoir 14 of the second sealed container 10. In addition, the oil equalizing pipe 25 may be provided in the refrigeration cycle apparatus of the first embodiment.

  Specifically, the refrigeration cycle apparatus 104 has a common path 52, a communication path 54, and a bypass path that branches from the communication path 54 and joins the common path 52 as the high-pressure refrigerant path 50 that guides the compressed refrigerant to the radiator 4. 56. The bypass path 56 includes a bypass pipe 70 and a valve 70a. When the bypass path 56 is provided, a part of the oil flowing out from the second sealed container 10 together with the refrigerant is guided to the first sealed container 9, while the remaining part is guided to the first pipe 3 a so as to bypass the first sealed container 9. . Since the bypass path 56 is a path branched from the communication path 54, it is not necessary to directly insert the bypass pipe 70 into the second sealed container 10, and assembly is easy. Further, the valve 70 a may be provided at a connection portion between the bypass pipe 70 and the communication pipe 48.

  As described in the first embodiment, since the oil levels S1 and S2 automatically settle at predetermined positions, it is not essential to manage them actively. However, there is a possibility that the oil levels S1 and S2 may reach out of the designed range due to sudden changes in operating conditions. By actively managing the oil level S1 and / or S2, it is possible to prepare for an emergency.

  Specifically, as shown in FIG. 8, a controller 76 for controlling opening and closing of the valve 70a and an oil level sensor 72 for detecting the oil level S1 of the first oil reservoir 13 are provided. The oil level sensor 72 uses a float that moves up and down according to the oil level S1, detects the oil level S1 based on a change in capacitance, and determines the oil level S1 based on the resistance value between the electrodes. Various level sensors can be used, such as those that detect the oil level S1 using ultrasonic waves.

  Based on the oil level information detected by the oil level sensor 72, the controller 76 controls the opening and closing of the valve 70a. For example, the valve 70a is closed on the condition that the oil level S1 is lower than a predetermined oil shortage level, while the valve 70a is opened on the condition that the oil level S1 is higher than a predetermined oil excess level. In this way, the oil level S1 can be managed more accurately without changing the rotational speeds of the first compressor 101 and the second compressor 102 at all.

  An oil level sensor 74 for detecting the oil level S2 of the second oil reservoir 14 may be provided. That is, instead of the oil level S1 of the first oil reservoir 13, or the oil level S2 of the second oil reservoir 14 is detected together with the oil level S1 of the first oil reservoir 13, the valve 70a is opened and closed based on the detection result. May be controlled.

  Further, the valve 70a may be a flow rate adjusting valve. When the flow rate adjusting valve is used, the mass flow rates of the refrigerant and the oil flowing into the first sealed container 9 through the communication path 54 can be adjusted. That is, when the opening degree of the valve 70a is increased, the amount of refrigerant and oil flowing into the first sealed container 9 through the communication path 54 decreases, and when the opening degree of the valve 70a is reduced, the first sealed container 9 is passed through the communication path 54. The amount of refrigerant and oil flowing in increases.

For example, the opening degree of the valve 70a is controlled according to the rotation speed of the first electric motor 11. The mass flow rate F _{exp of the} oil mixed with the refrigerant in the expansion mechanism 5 is approximately proportional to the rotational speed of the first electric motor 11, and F _exp increases when the rotational speed of the first electric motor 11 is high. It moves from the compressor 102 side to the first compressor 101 side. On the other hand, when the rotational speed of the first electric motor 11 is low, F _exp also decreases, so that only a small amount of oil needs to be moved from the second compressor 102 side to the first compressor 101 side. By performing such control, the oil level of each oil reservoir can be stably maintained.

  In addition, according to the present embodiment, the oil equalizing pipe 25 that connects the first oil reservoir 13 and the second oil reservoir 14 is provided. As described above, the oil leveling pipe 25 is not universal, but the oil level of each oil reservoir can be more stably maintained by the synergistic effect of the oil leveling pipe 25 and the communication path 54.

  The oil equalizing pipe 25 may be provided with a valve 25a. By opening the oil equalizing pipe valve 25a when the operation is stopped, an imbalance in the oil retention amount between the first oil reservoir 13 and the second oil reservoir 14 can be eliminated. During the operation of the refrigeration cycle apparatus 104, the valve 25a may be slightly opened or closed. By reducing the amount of oil directly moving from the second oil reservoir 14 to the first oil reservoir 13 through the valve 25a as much as possible, heat can be prevented from moving from the second compression mechanism 2 to the expansion mechanism 5 via the oil. As a result, the temperature drop of the compressed refrigerant and the temperature rise of the expanded refrigerant are suppressed, and the COP of the refrigeration cycle apparatus is improved.

(Third embodiment)
As shown in FIG. 9, the refrigeration cycle apparatus 105 of the present embodiment is different from the second embodiment in the positions of the suppression plate and oil equalizing pipe that suppress the flow of oil. Specifically, in the present embodiment, the first suppression plate 17 is positioned above the second suppression plate 18 in the vertical direction.

  According to this embodiment, the oil levels S1 and S2 are aligned on the same horizontal plane by opening the oil equalizing valve 25a when the operation is stopped. As a result, the space v2 between the oil level S2 and the second electric motor 12 is narrower than the space v1 between the oil level S1 and the first electric motor 11. When the operation of the refrigeration cycle apparatus 105 is resumed in this state, the mass flow rate of oil exiting the second sealed container 10 (Fd2 shown in FIGS. 5 and 6) becomes relatively large. This is because when the space v2 is narrow, the oil is difficult to be separated from the refrigerant in the space v2. As a result, the mass flow rate Fd2 of the oil flowing out from the second sealed container 10 increases immediately after the start of operation, and the time t1 described with reference to FIG. 6 (the time spent from the start of operation to the transition to the steady state) ) Becomes shorter.

(Modification)
The effects described in the embodiments can be obtained regardless of whether the rotation speed of the first compressor 101 and the rotation speed of the second compressor 102 are the same or different.

  The first oil pump 15 may be provided at the lower end of the first shaft 23, and the first oil pump 15 may be used to supply oil to the first compression mechanism 1 and the expansion mechanism 5. In this case, the upper bearing member 29 of the expansion mechanism 5 may be positioned above the oil level S <b> 1 in the vertical direction, and the outer peripheral portion of the upper bearing member 29 may be extended until it contacts the first sealed container 9. By doing so, the upper bearing member 29 can have a function of suppressing the flow of oil. However, if the first oil pump 15 and the first oil suction port 15a are positioned above the expansion mechanism 5, the oil heated by the first compression mechanism 1 can be prevented from flowing around the expansion mechanism 5. That is, heat can be prevented from moving from the first compression mechanism 1 to the expansion mechanism 5 through the oil.

  In the first compressor 101, the positional relationship between the first compression mechanism 1 and the expansion mechanism 5 may be upside down. Further, in the second compressor 101, the arrangement of the second compression mechanism 2 and the second electric motor 12 may be upside down.

  The first compressor 101 may be a horizontal type in which the axial direction of the first shaft 23 is parallel to the horizontal direction. As long as the oil reservoir is shared by the first compression mechanism 1 and the expansion mechanism 5, the effect of the present invention can be obtained. Similarly, the second compressor 102 may be a horizontal type.

  In the first compressor 101, the first oil sump 13 may be divided into a plurality of sections. When the first compressor 101 is of a horizontal type, an oil reservoir for the first compression mechanism 1 and an oil reservoir for the expansion mechanism 5 can be formed by providing a partition in the first sealed container 9.

  The refrigerant circuit may be switchable between a high pressure side and a low pressure side. For example, switching means such as a four-way valve for changing the flow direction of the refrigerant may be provided in the refrigerant circuit.

The block diagram of the refrigerating-cycle apparatus concerning 1st Embodiment of this invention. The longitudinal cross-sectional view of the 1st compressor used for the refrigeration cycle apparatus shown in FIG. FIG. 2 is a cross-sectional view taken along line AA of the first compressor shown in FIG. The cross-sectional view along the BB line of the 1st compressor shown in FIG. The longitudinal cross-sectional view of the 2nd compressor used for the refrigeration cycle apparatus shown in FIG. Explanatory drawing of oil flow during operation of refrigeration cycle equipment Graph showing time change of oil flow rate Longitudinal sectional view of the first compressor with the connection position of the introduction pipe changed The block diagram of the refrigerating-cycle apparatus concerning 2nd Embodiment of this invention. Configuration diagram of a modified example in which the positions of the oil flow suppression plate and the oil equalizing pipe are changed Configuration diagram of conventional power recovery refrigeration cycle equipment Configuration diagram of a conventional refrigeration cycle apparatus equipped with two compressors External view of two compressors connected by oil leveling pipes

DESCRIPTION OF SYMBOLS 1 1st compression mechanism 2 2nd compression mechanism 4 Radiator 5 Expansion mechanism 6 Evaporator 7 1st suction pipe 8 2nd suction pipe 9 1st airtight container 10 2nd airtight container 11 1st electric motor 12 2nd electric motor 13 1st Oil reservoir 14 Second oil reservoir 15 First oil pump 19 First discharge pipe 20 Second discharge pipe 23 First shaft 24 Second shaft 25 Oil equalization pipe 48 Communication pipe 49 Introduction pipe 50 High-pressure refrigerant path 52 Common path 54 Communication path 56 Bypass path 70a Valves 100, 104, 105 Refrigeration cycle apparatus 101 First compressor 102 Second compressor

Claims (16)

A first compression mechanism, an expansion mechanism, a shaft connecting the first compression mechanism and the expansion mechanism, the first compression mechanism, the expansion mechanism, and the shaft; A first compressor having a first sealed container whose internal space is filled with a compressed refrigerant;
A second compressor having a second compression mechanism disposed in parallel with the first compression mechanism in the refrigerant circuit; and a second hermetic container for housing the second compression mechanism;
A radiator that cools the refrigerant compressed by the first compression mechanism and the refrigerant compressed by the second compression mechanism;
An evaporator for evaporating the refrigerant expanded by the expansion mechanism;
A path for guiding the refrigerant compressed by the first compression mechanism and the refrigerant compressed by the second compression mechanism to the radiator, a common path connecting the first sealed container and the radiator, A communication path that connects the second sealed container and the first sealed container so that the refrigerant compressed by the second compression mechanism is guided to the radiator via the internal space of the first sealed container. Having a high pressure refrigerant path;
A refrigeration cycle apparatus comprising:   The refrigeration cycle apparatus according to claim 1, wherein a pressure at an inlet of the communication path is higher than a pressure at an outlet during operation of the refrigeration cycle apparatus. The second compressor is a high-pressure shell type in which an internal space of the second sealed container is filled with a refrigerant compressed by the second compression mechanism,
The refrigeration cycle apparatus according to claim 1 or 2, wherein the communication path communicates the internal space of the second sealed container and the internal space of the first sealed container.   The refrigeration cycle apparatus according to any one of claims 1 to 3, wherein the entire amount of the refrigerant compressed by the second compression mechanism can flow through the communication path and be guided to the radiator.   The refrigeration cycle apparatus according to any one of claims 1 to 4, wherein the refrigerant compressed by the second compression mechanism flows in the communication path only in a direction from the second sealed container to the first sealed container. . The first compressor further includes a first electric motor disposed between the first compression mechanism and the expansion mechanism to drive the shaft;
In the first sealed container, an inlet of the common path is located above the first electric motor, and an outlet of the communication path is located below the first electric motor. The refrigeration cycle apparatus according to any one of the above. The axial direction of the shaft of the first compressor is parallel to the vertical direction;
The refrigeration according to claim 6, wherein the refrigerant guided to the internal space of the first sealed container through the communication path proceeds in the vertical direction in the space around or in the first electric motor to reach the inlet of the common path. Cycle equipment. The axial direction of the shaft of the first compressor is parallel to the vertical direction;
In the first sealed container, the first compression mechanism is disposed above the first electric motor, and the expansion mechanism is disposed below the first electric motor,
The refrigerant compressed by the first compression mechanism passes through the first electric motor and is guided to a lower space of the first electric motor. In the space, the refrigerant compressed by the first compressor and the The refrigeration cycle apparatus according to claim 6, wherein the refrigerant compressed by the second compression mechanism merges, and then proceeds upward in a space around the first electric motor to reach the inlet of the common path. The first compressor includes an upper space in which the first compression mechanism and the first electric motor are disposed in an inner space of the first sealed container along an axial direction of the shaft, and the expansion mechanism is disposed. Further comprising a suppressing member that suppresses the flow of oil stored in the bottom of the first sealed container by partitioning with a lower space that is
The refrigeration cycle apparatus according to any one of claims 5 to 8, wherein an outlet of the communication path is located between the first electric motor and the suppression member with respect to the vertical direction. The first compressor and the expansion mechanism for supplying the oil stored in the bottom of the first sealed container to one or both of the first compression mechanism and the expansion mechanism. And further comprising an oil pump disposed between
The oil supply path extending in an axial direction is formed in the shaft so that oil discharged from the oil pump is guided to one or both of the first compression mechanism and the expansion mechanism. Refrigeration cycle equipment. The axial direction of the shaft of the first compressor is parallel to the vertical direction;
In the first sealed container, the first compression mechanism, the first electric motor, the suppression member, the oil pump and the expansion mechanism are arranged in this order from the top,
The refrigeration cycle apparatus according to claim 10, wherein oil sucked into the oil pump is supplied to the first compression mechanism through the oil supply passage. The second compressor is a second electric motor disposed in the second hermetic container, and a second shaft connecting the second compression mechanism and the second electric motor so that the second electric motor is aligned in a vertical direction; The second sealed container is partitioned by dividing the internal space of the second sealed container into an upper space in which the second compression mechanism and the second electric motor are arranged and a lower space in which oil is stored, along the vertical direction. A second restraining member that restrains the flow of oil stored in the bottom of the
The refrigeration cycle apparatus according to any one of claims 9 to 11, wherein the suppression member of the first compressor is positioned above the second suppression member of the second compressor in the vertical direction.   The refrigeration cycle apparatus according to any one of claims 1 to 12, wherein the high-pressure refrigerant path further includes a bypass path that branches from the communication path and joins the common path.   14. The oil leveling pipe according to claim 1, further comprising an oil equalizing pipe communicating the first oil reservoir formed at the bottom of the first sealed container and the second oil reservoir formed at the bottom of the second sealed container. The refrigeration cycle apparatus according to item 1.   The refrigeration cycle apparatus according to any one of claims 1 to 14, wherein a type of the first compression mechanism and a second compression mechanism is a scroll type, and a type of the expansion mechanism is a rotary type.   The refrigeration cycle apparatus according to any one of claims 1 to 15, wherein the refrigerant is carbon dioxide.

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