JPWO2012029203A1 - Expander and refrigeration cycle equipment - Google Patents

Abstract

Installation of oil equalization pipes and pressure equalization pipes, installation restrictions such as height, etc. do not occur, and there is no stirring loss due to balance weight, and oil supply to each bearing part using high-pressure oil supplied from an oil separator is possible A rotary expander is provided. A first space (4a) in which high-pressure oil is supplied from an oil separator (26) through an oil supply hole (4c) penetrating the container (4) inside the container (4), and a first space (4a) The balance weights (79a, 79b) are divided into the second space (4b) having a lower pressure atmosphere, and are supported by the shaft (78) and rotate integrally with the shaft (78) in the second space (4b). ) And the shaft (78) penetrates the shaft (78) in the axial direction, one end opens to the first space (4a), and the other end opens to the second space (4b). ) And each bearing oil supply hole (78d) penetrating in the radial direction of the shaft (78) from the oil hole (78a) and communicating with each bearing portion (51c, 52d, 61c), and the first space (4a ) Oil in each of the bearing portions (51c, 52d, 61c) from one end of the oil hole (78a) through the bearing oil supply hole (78d). It is pressure refueling.

Description

  The present invention relates to an expander that recovers power from an expansion process and a refrigeration cycle apparatus including the expander.

  In the refrigeration cycle apparatus for refrigeration and air conditioning, the cycle C.I. O. P. (Coefficient of Performance) As an improvement means, an expander that recovers power from an expansion process is used. As an expander that performs power recovery, for example, a rotation in which a expansion mechanism that expands a refrigerant and a sub-compression mechanism that is coaxially connected to the expansion mechanism and driven by power recovered by the expansion mechanism are accommodated in a container. There is a type of expander. When this type of expander is used in a refrigeration cycle, there are two devices having a portion requiring lubrication, such as a bearing portion and a sliding portion, a compressor and an expander in the cycle. Therefore, it is necessary to supply oil not only to the compressor but also to the expansion mechanism, and consideration must be given so that the oil is not exhausted in each of the compressor and the expander. Therefore, conventionally, each container of the expander and the compressor is connected by a pressure equalizing pipe, and oil reservoirs provided at the bottom of each container are connected by an oil equalizing pipe so that the oil level is between the expander and the compressor. There is a refrigeration cycle apparatus in which the oil level is controlled so that the positions are equal (for example, see Patent Document 1).

  As another refrigeration cycle apparatus, for example, an oil separator is provided on the high pressure side, and high pressure oil separated by the oil separator is directly supplied to both the expansion mechanism and the compression mechanism of the expander by differential pressure. There is a refrigeration cycle apparatus (see, for example, Patent Document 2). This refrigeration cycle apparatus employs a swash plate type expander using a rolling bearing.

  Further, in a rotary expander that recovers power, balance weights are arranged at one end and the other end of a shaft that connects the expansion mechanism and the sub-compression mechanism, respectively, and the expansion mechanism and the compression mechanism are independently static and The balance is dynamically made (see, for example, Patent Document 3). Further, in an expander that performs this type of power recovery, the expansion mechanism and the sub-compression mechanism are integrally formed coaxially, so that the volume flow rate that passes through the expansion mechanism can be adjusted so that the rotational speeds of the expansion mechanism and the sub-compression mechanism coincide with each other. is necessary. Therefore, in the refrigeration cycle device of Patent Document 3, the expansion mechanism is bypassed to reduce the flow rate on the expansion mechanism inlet side, or pre-expansion is performed before flowing into the expansion mechanism to increase the specific volume of the expansion mechanism inlet. Adjustments are made.

Japanese Patent Laying-Open No. 2008-233201 ([0018], FIG. 1) JP 2001-141315 A ([0031], FIG. 1) JP 2009-24546 A ([0021], FIG. 2)

  In the refrigeration cycle apparatus of Patent Document 1, for the convenience of making the oil surface position equal between the expander and the compressor, the expander must be installed at almost the same height as the compressor, and the installation position is restricted. there were. On the other hand, in the refrigeration cycle apparatus of Patent Document 2, since the oil stored in the oil separator is directly supplied by differential pressure, installation restrictions such as the installation of the oil equalizing pipe and the pressure equalizing pipe, and the height do not occur. However, the expander used in the refrigeration cycle apparatus of Patent Document 2 is a swash plate type expander using a rolling bearing, and in the rotary expander, installation of oil equalization pipes and pressure equalization pipes, installation of height, etc. There has not yet been proposed an expander that lubricates the bearing portion using high-pressure oil supplied from an oil separator without restriction.

  Further, in the refrigeration cycle apparatus of Patent Document 3, a balance weight is provided, but when the balance weight is immersed in oil stored in the container of the expander, the balance weight causes agitation loss due to agitation of the oil. There was a problem that power loss occurred. Therefore, in the case of a rotary expander, it is necessary to consider that the balance weight is not immersed in oil.

  Further, in the refrigeration cycle apparatus of Patent Document 3, the volume flow rate is adjusted by bypass or pre-expansion of the expansion mechanism. However, in this method, the flow rate of the bypass or pre-expansion cannot recover the expansion power. The recovery flow rate. Therefore, there is a problem that the power recovery effect is lowered and the energy efficiency is lowered.

  The present invention has been made in view of the above points, and does not cause installation restrictions such as the installation of oil equalization pipes and pressure equalization pipes, height, and the like, and further, high pressure supplied from the oil separator without agitation loss due to the balance weight. An object of the present invention is to obtain a rotary expander capable of supplying oil to each bearing portion using the above oil.

  It is another object of the present invention to provide a refrigeration cycle apparatus capable of adjusting the volume flow rate without depending on expansion side bypass or pre-expansion and improving energy efficiency.

  An expander according to the present invention includes an expansion mechanism that recovers power by expanding a refrigerant, a compression mechanism that is coupled to the expansion mechanism via a shaft, and that compresses the refrigerant by the power recovered by the expansion mechanism, and the expansion mechanism and the compression mechanism A container that houses the mechanism, and the inside of the container is a first space in which high-pressure oil is supplied from an oil separator through an oil supply hole that penetrates the container, and a second atmosphere that has a lower-pressure atmosphere than the first space. A balance weight that is divided into a space and is supported by a shaft and rotates integrally with the shaft is arranged in the second space, the shaft penetrates the shaft in the axial direction, and one end opens into the first space, An oil supply passage whose other end opens into the second space, and each bearing oil supply hole that penetrates from the oil supply passage in the radial direction of the shaft and communicates with each bearing portion for each shaft of the expansion mechanism and the compression mechanism, Each bearing is filled with oil from one end of the oil supply passage through the bearing oil supply hole. It is intended to be a differential pressure refuel.

  The refrigeration cycle apparatus of the present invention includes a main compression mechanism that compresses refrigerant, an oil separator that separates refrigerant that has passed through the main compression mechanism and oil contained in the refrigerant, and refrigerant that has passed through the main compression mechanism. A radiator that cools the refrigerant, an expander that expands the refrigerant that has passed through the radiator, and an evaporator that evaporates the refrigerant expanded by the expander, which are sequentially connected by piping to circulate the refrigerant The expander is configured by the expansion mechanism according to claim 1, and a part of the refrigerant from the evaporator toward the main compression mechanism is supplied to the compression mechanism of the expander and compressed, and then the main compression Supply the oil in the middle of compression of the mechanism, return the oil separated by the oil separator to the pipe between the main compression mechanism and the evaporator, and the oil separated by the oil separator in the container And a sub oil return pipe to be sent to the oil supply hole.

According to the present invention, each bearing portion using high-pressure oil supplied from the oil separator without installation restrictions such as the installation of oil equalization pipes and pressure equalization pipes, height, and the like, and further without stirring loss due to the balance weight. A rotary expander capable of refueling can be obtained.
Moreover, the refrigeration cycle apparatus which can improve energy efficiency can be obtained.

It is a schematic sectional drawing of the expander which concerns on one embodiment of this invention. It is a schematic sectional drawing which shows another cross section of the expander of FIG. It is a circuit block diagram which shows the refrigerating-cycle apparatus carrying the expander of FIG. It is a Mollier diagram explaining the state of the refrigerant | coolant in the refrigerating cycle using the expander of this invention.

  FIG. 1 is a schematic sectional view of an expander according to an embodiment of the present invention. In the following drawings, the same reference numerals denote the same or corresponding parts, which are common throughout the entire specification. Furthermore, the form of the constituent elements appearing in the whole specification is merely an example, and is not limited to these descriptions.

  The expander 1 is connected to the expansion mechanism 2 that expands the refrigerant and recovers power in the sealed container 4, and is connected to the expansion mechanism 2 via a shaft 78, and compresses the refrigerant by the power recovered by the expansion mechanism 2. And a sub-compression mechanism 3. Below the sealed container 4, an expansion fixed scroll 51 constituting the expansion mechanism 2 is disposed. The expansion fixed scroll 51 has a configuration in which spiral teeth 51b are erected upward from the base plate 51a. A sub-compression fixed scroll 61 constituting the sub-compression mechanism 3 is disposed above the sealed container 4. The sub-compression fixed scroll 61 also has a configuration in which spiral teeth 61b are erected downward from the base plate 61a. A swing scroll 52 is disposed between the expansion fixed scroll 51 and the sub compression fixed scroll 61.

  The swing scroll 52 is provided with an expansion side spiral tooth 52b that engages with the spiral tooth 51b of the expansion fixed scroll 51 on one surface of the base plate 52a facing the expansion fixed scroll 51, and the expansion mechanism 2 together with the expansion fixed scroll 51. Is configured. The swing scroll 52 has a sub-compression-side spiral tooth 52c that is engaged with the spiral tooth 61b of the sub-compression fixed scroll 61 on the other surface of the base plate 52a facing the sub-compression fixed scroll 61. The sub-compression mechanism 3 is configured together with the scroll 61.

  A shaft 78 passes through the center of the sub-compression fixed scroll 61, the swing scroll 52 and the expansion fixed scroll 51 in the vertical direction. The shaft 78 is rotatably supported by an expansion side bearing portion 51c and a sub compression side bearing portion 61c formed at the center of each of the expansion fixed scroll 51 and the sub compression fixed scroll 61. The orbiting scroll 52 has an orbiting bearing portion 52d formed at its center penetrating and supported by a crank (eccentricity) portion formed on a shaft 78 so as to be able to swing. Further, an Oldham ring 77 is disposed between the swing scroll 52 and the expansion fixed scroll 51 to prevent the swing scroll 52 from rotating and to regulate the posture.

  In the expander 1, the shaft 78 rotates and the rocking scroll 52 performs a rocking motion, so that the refrigerant expands and compresses. That is, on the expansion mechanism 2 side, an expansion chamber is formed between the expansion scroll 52 and the expansion fixed scroll 51 by swinging along the circular orbit of the swing scroll 52 while increasing the volume while moving from the center to the peripheral direction. Here, the expansion action is performed. On the other hand, on the sub-compressor side, a compression chamber is formed between the sub-compression fixed scroll 61 and the sub-compression fixed scroll 61 by moving along the circular orbit of the orbiting scroll 52 while moving in the center direction from the outer peripheral portion. Here, the compression action is performed.

  Inside the sealed container 4, the first space 4 a on the back side of the expansion fixed scroll 51, the second space 4 b on the back side of the sub compression fixed scroll 61, and the swing between the expansion fixed scroll 51 and the sub compression fixed scroll 61. The scroll motion space 61e is divided into three parts. An oil supply hole 4c communicating with the first space is formed through the sealed container 4 and oil from an oil separator 26 described later is supplied to the oil supply hole 4c by an oil supply pipe 37 connected from the outside of the closed container 4. 1 space 4a is supplied and filled. In addition, an air intake hole 4d communicating with the second space 4b is formed in the sealed container 4 so that the refrigerant from the outside is supplied to the intake hole 4d by the sub-compression suction pipe 19 connected from the outside of the airtight container 4. 2 space 4b is supplied. In this example, the second space 4 b is the suction pressure atmosphere of the sub compression mechanism 3. The sub-compression fixed scroll 61 is formed with a sub-compression suction communication passage 61d penetrating in the axial direction. The sub-compression suction communication passage 61d allows the second space 4b and the orbiting scroll motion space 61e to communicate with each other. Virtually the same space.

  The shaft 78 has an oil hole 78a that is an oil supply passage penetrating in the axial direction therein, and one end 78b of the oil hole 78a opens to the oil filled in the first space 4a, and the other end 78c of the oil hole 78a is It opens to the second space 4b. Further, the shaft 78 has a plurality of bearing oil supply holes 78d that are formed through the oil holes 78a in the radial direction and communicate with the expansion side bearing portion 51c, the swinging bearing portion 52d, and the sub compression side bearing portion 61c. . Further, balance weights 79 a and 79 b that rotate integrally with the shaft 78 are attached to the protruding portion of the shaft 78 that protrudes into the second space 4 b. The balance weight 79b in the same eccentric direction as the swing scroll 52 and the balance weight 79a in the anti-eccentric direction are adjacent to each other, and both the static scroll and the dynamic balance are provided by the swing scroll 52 and the balance weights 79a and 79b. Is supposed to take.

FIG. 2 is a schematic cross-sectional view showing another cross section of the expander of FIG.
In the sub-compression mechanism 3, a sub-compression discharge port 40 that communicates with the sub-compression chamber is formed in the base plate 61 a of the sub-compression fixed scroll 61 in the axial direction. A discharge valve 32 for opening and closing the sub compression discharge port 40 is disposed. The base plate 61a of the sub-compression fixed scroll 61 is further formed with a valve space 33 in which the discharge valve 32 is disposed, and a sub-compression discharge passage 61f that penetrates the base plate 61a from the valve space 33 in the radial direction. . A sub compression discharge pipe 20 inserted through the sealed container 4 is connected to the sub compression discharge flow path 61f. As described above, the first space 4a is the suction pressure atmosphere of the sub-compression mechanism 3, and the refrigerant at the suction pressure is compressed in the compression chamber of the sub-compression mechanism 3, and then discharged from the discharge valve 32, and the sub-compression It passes through the discharge flow path 61f and is discharged from the sub-compression discharge pipe 20 to the outside of the sealed container 4. Note that the opening of the valve space 33 on the second space 4 b side is closed by the plate 34.

  In the expansion mechanism 2, an expansion suction port 35 communicating with the expansion chamber and an expansion suction flow path 51 d communicating with the expansion suction port 35 are formed on the base plate 51 a of the expansion fixed scroll 51. An expansion suction pipe 15 that is inserted through the sealed container 4 and communicates with the expansion suction flow path 51d is further connected to the base plate 51a of the expansion fixed scroll 51. Further, an expansion / discharge port 36 communicating with the expansion chamber and an expansion / discharge channel 51e communicating with the expansion / discharge port 36 are further formed on the base plate 51a of the expansion fixed scroll 51. An expansion / discharge pipe 16 that is inserted through the sealed container 4 and communicates with the expansion / discharge flow path 51e is further connected to the base plate 51a of the expansion fixed scroll 51. With this configuration, in the expansion mechanism 2, the refrigerant is directly sucked from outside the sealed container 4, expanded in the expansion chamber, and then discharged directly from the expansion discharge pipe 16 to the outside of the sealed container 4 without being discharged into the sealed container 4. Is done.

  An eccentric seal 72a is provided at the center of the expansion side spiral tooth 52b of the swing scroll 52 so as to surround the swing bearing portion 52d, and seals the inlet of the expansion mechanism 2 and the inside of the sealed container 4. Yes. A concentric seal 73 is provided surrounding the sub-compression side spiral teeth 52c of the orbiting scroll 52, and an eccentric seal 72b is provided further outside. The base plate 52a of the orbiting scroll 52 is formed with a high pressure introduction hole 52e penetrating in the axial direction from the expansion chamber forming portion of the expansion side spiral tooth 52b. The sub compression side of the high pressure introduction hole 52e is a concentric seal 73. And an opening between the eccentric seal 72b. The operation of the high pressure introduction hole 52e will be described later.

FIG. 3 is a cycle configuration diagram schematically showing a refrigeration cycle apparatus equipped with an expander according to the present invention.
This refrigeration cycle apparatus includes a main compressor 5 having a main compression mechanism 7 driven by a motor 6, an oil separator 26, a radiator 11, a pre-expansion valve 14, and an expansion mechanism 2 in the expander 1. The evaporator 12 is sequentially connected by piping. A pipe between the evaporator 12 and the main compression mechanism 7 and the sub compression suction pipe 19 of the sub compression mechanism 3 are connected by a pipe 80, and a part of the refrigerant from the evaporator 12 toward the main compression mechanism 7 is piped. After 80, it is supplied to the sub-compression mechanism 3 in the expander 1. Further, the sub compression discharge pipe 20 of the sub compression mechanism 3 and the suction port in the middle of compression of the main compression mechanism 7 are connected by a pipe 81 having a check valve 82, and the refrigerant compressed by the sub compression mechanism 3 is connected to the pipe 81. Then, it is introduced into the compression chamber in the middle of compression of the main compression mechanism 7.

  When electricity is supplied to the motor 6, the main compressor 5 is driven, and the refrigerant is pressurized by the main compression mechanism 7 of the main compressor 5. And after the oil contained in this refrigerant | coolant is isolate | separated from the pressure-reduced refrigerant | coolant by the oil separator 26, it introduce | transduces into the heat radiator 11 and is cooled. Then, the high-pressure refrigerant cooled by the radiator 11 is sent to the expansion mechanism 2 of the expander 1 through the pre-expansion valve 14 and is decompressed and decompressed. The pre-expansion valve 14 is for controlling the pressure on the side of the expansion mechanism 2 at the time of transition such as startup, and is fully opened at the time of steady state so as not to be involved in flow rate / power matching. The refrigerant decompressed by the expansion mechanism 2 is heated by the evaporator 12 and then returns to the main compression mechanism 7 of the main compressor 5 again. A part of the refrigerant returning from the evaporator 12 to the main compressor 5 is supplied to the sub compression mechanism 3 in the expander 1 through the pipe 80 as described above, and after being compressed to the intermediate pressure by the sub compression mechanism 3, It is introduced into a compression chamber in the middle of compression of the main compression mechanism 7 through a pipe 81 having a check valve 82. In the main compression mechanism 7, the refrigerant flowing in from the evaporator 12 is compressed to an intermediate pressure, merged with the refrigerant flowing in from the sub-compression mechanism 7, and compressed together with the refrigerant to a high pressure.

  In the expander 1, when the power generated when the refrigerant is depressurized is recovered by the expansion mechanism 2 and the sub-compression mechanism 3 is driven, the refrigerant circulating in the refrigeration cycle apparatus is transferred to the sub-compression mechanism 3 and the main compressor 5. w: Divided by (1-w). In the refrigeration cycle apparatus of this example, volume flow rate adjustment is performed by splitting main compression / sub-compression to satisfy the condition that the rotational speed determined on the expansion mechanism 2 side matches the rotational speed on the sub-compression mechanism 3 side. The flow rate passing through the expansion mechanism 2 is Ge, the flow rate passing through the sub-compression mechanism 3 is Gc, the refrigerant specific volume at the expansion mechanism inlet is vexi, the refrigerant specific volume at the sub-compression mechanism inlet is vs, and the expansion mechanism suction volume is Vei. When the sub compression mechanism suction volume is Vcs, the expression (1) must be satisfied.

  Here, the expansion mechanism suction volume / sub-compression mechanism suction volume = σvEC *. The weight flow rate Gc / weight flow rate Ge = w. If the above equation (1) is rearranged using these equations, w becomes the following equation (2). Therefore, the inlet volume flow rate of the expansion mechanism 2 and the sub compression mechanism 3 can be balanced by adjusting the suction amount of the main compressor 5 so that w satisfies the following expression (2).

  In addition to the balance of the inlet volume flow rates of the expansion mechanism 2 and the sub-compression mechanism 3, the power and balance between the expansion mechanism 2 and the sub-compression mechanism 3 are required. The refrigerant having a flow ratio w is compressed from Pl to the intermediate pressure Pm by the sub-compression mechanism 3 by the power recovered by the expansion mechanism 2, and the additional compression from Pm to the high pressure Ph is performed along with the (1-w) minute main compression mechanism. 7, the power between the expansion mechanism 2 and the sub-compression mechanism 3 can be balanced.

  That is, the suction volume ratio σvEC * of the expander 1 is fixed, and the recovery power is determined depending on the conditions. On the other hand, the flow rate is matched by dividing the subcompression mechanism 3 and the main compressor 5. Plan. Then, the refrigerant divided into the sub-compression mechanism 3 is merged by the main compression mechanism 7 and then subjected to additional compression, thereby absorbing the shift between the power necessary for boosting w from Pl to Ph and the recovered power. Will be. FIG. 3 shows the pre-expansion valve 14, which is for controlling the pressure on the expansion mechanism 2 side at the time of transition such as start-up as described above. And is not involved in the above power matching.

FIG. 4 is a Mollier diagram showing changes in the state quantity of the refrigerant in the refrigeration cycle apparatus of FIG. In FIG. 4, the vertical axis (logarithm) is the refrigerant pressure P, and the horizontal axis is the specific enthalpy h.
In the main compressor 5, the pressure of the refrigerant is increased from the low pressure Pl c1s to the high pressure Ph c1d. Here, since CO2 is assumed as the refrigerant, the pressure Ph exceeds the critical pressure. The refrigerant whose pressure has been increased to Ph is cooled by the radiator 11, thereby changing from c1d → exi. When the refrigerant at the outlet of the radiator 11 is depressurized with a throttle that does not collect power, such as an expansion valve, the refrigerant is depressurized from the point exi at a specific enthalpy to the point exo ′. On the other hand, when decompression is performed while generating expansion power by the expansion mechanism 2, the process of exo → exo is followed. The specific enthalpy difference hexo'-hexo at the time of decompression corresponds to the energy recovered as power, and is used as power when the sub-compression mechanism 3 compresses the flow rate w from c2s to c2d. The additional compression performed after joining the main compressor 5 with respect to the flow rate w is expressed by c2d → c1d, and the compression in the main compressor 5 for the flow rate (w−1) is expressed by c1s (= c2s · → c1d. .

  At this time, (enthalpy difference hc2s-hexo) × (flow rate 1) equivalent is the refrigerating capacity. Further, the energy recovered from the power (the enthalpy difference hc2d−hc2s equivalent to the flow rate w) is excluded, (enthalpy difference hc2d−hc1s) × (flow rate 1−w) + (enthalpy difference hc1d−hc2d) · (flow rate 1) A considerable amount of electrical input is consumed by the motor 6 of the main compressor 5. Therefore, this ratio (refrigeration capacity / power consumption) is the so-called cycle C.I. O. P. It becomes. Compared with the cycle c1s → c1d → exi → exo ”→ c1s without power recovery, the input (enthalpy difference hc2d−hc2s) × (flow rate w) and the refrigeration capacity (enthalpy difference hexo′−hexo). The amount of (flow rate 1) contributes to the improvement of COP.

  Here, the pressure acting on both surfaces of the swing scroll 52 and the high-pressure introduction hole 52e will be described. The sub-compression process in the sub-compression mechanism 3 is performed between c2s → c2d in the Mollier diagram of FIG. 4, and the expansion process in the expansion mechanism 2 is performed between exi → exo. Therefore, the pressure acting on both surfaces of the orbiting scroll 52 is greater from the expansion mechanism 2 side than from the sub compression mechanism 3 side. Therefore, the Oldham ring 77 is arranged on the outer peripheral portion of the expansion side spiral, with the spiral specification having a larger outer diameter on the sub-compression mechanism 3 side and the outer diameter being suppressed on the expansion mechanism 2 side as much as possible. However, normally, the tip pressing force of the sub compression side spiral tooth 52c becomes excessive due to the axial gas load (thrust) from the expansion mechanism 2 side to the sub compression mechanism 3 side. Since the expander 1 of the present invention has no drive source other than the recovered expansion power, an excessive pressing force causes the recovered power to be wasted or cannot be operated. For this reason, the high pressure (point exi on the Mollier diagram) on the expansion inlet side is guided to the surface on the sub compression mechanism 3 side by the high pressure introduction hole 52e, and the thrust toward the sub compression mechanism 3 side (= sub compression side spiral teeth) The first pressing force is reduced.

  Next, the oil supply path to the expander and the oil flow will be described. The oil separator 26 includes a main oil return pipe 22 a that returns the oil separated by the oil separator 26 to a pipe between the evaporator 12 and the main compressor 5, and a sub oil return pipe that returns the oil to the expander 1. 22b is connected. One end of the sub oil return pipe 22b is connected to the oil separator 26, and the other end is connected to the oil supply pipe 37 penetrating the sealed container 4, and the oil from the oil separator 26 is guided to the oil supply pipe 37 to enter the second space 4b. Let it be introduced.

  The oil separated by the oil separator 26 provided on the high pressure side is generally returned to the suction side of the compressor by an oil return pipe having a constant resistance such as a capillary. However, in this embodiment, the variable throttle 27 is provided in the main oil return pipe 22a so that the resistance during oil return can be changed. The variable throttle 27 adjusts the amount of oil returned from the oil separator 26 to the suction side of the main compressor 5 to be appropriate. The sub oil return pipe 22b is a pipe that depressurizes with a constant resistance, and supplies the oil separated by the oil separator 26 with a constant resistance to the first space 4a of the expander 1.

  The first space 4a is filled with oil from the oil separator 26 and has an oil pressure atmosphere. On the other hand, the second space 4b is in the suction pressure atmosphere by the refrigerant sucked from the sub compression suction pipe 19 as described above. The pressure atmosphere in the first space 4a depends on the resistance of the sub oil return pipe 22b. Here, the sub oil return pipe has a pressure difference between one end 78b and the other end 78c of the oil hole 78a. A resistance of 22b is set. Therefore, the oil in the first space 4a is sucked in from the one end 78b of the oil hole 78a due to the pressure difference generated between the one end 78b and the other end 78c of the oil hole 78a, and the expansion side bearing portion 51c from each bearing oil supply hole 78d. The sub-compression side bearing portion 61c and the swing bearing portion 52d are respectively supplied with differential pressure. The resistance of the sub oil return pipe 22b is set so that the pressure difference between the one end 78b and the other end 78c of the oil hole 78a becomes a pressure head corresponding to the length of the shaft 78.

  The refrigerant that has lubricated the expansion side bearing portion 51c, the sub compression side bearing portion 61c, and the rocking bearing portion 52d overflows into the second space 4b and together with the refrigerant for the flow rate w flowing from the sub compression suction pipe 19, the sub compression suction. It flows into the orbiting scroll motion space 61e through the communication path 61d. The refrigerant that has flowed into the orbiting scroll motion space 61 e is sub-compressed by the sub-compression mechanism 3 and sent from the sub-compression discharge pipe 20 to the main compression mechanism 7. Accordingly, the orbiting scroll motion space 61e has an oil-rich atmosphere, and oil is also supplied to the claw sliding portion of the Oldham ring 77 in this space.

  The sub-compressed refrigerant is further compressed by the main compression mechanism 7 and then discharged, and reaches the oil separator 26. Therefore, the oil in the refrigerant also returns to the oil separator 26. Therefore, the oil separator 26, the sub oil return pipe 22b, the first space 4a, the bearings, the orbiting scroll motion space 61e, the sub compression mechanism 3, the additional compression mechanism (main compression mechanism 7), and the oil separator 26. An oil supply system of the expander 1 is configured.

  The amount of oil supplied to the expander 1 is determined by the differential pressure between the high pressure of the oil separator 26 and the low pressure of the outlet of the evaporator 12 and the resistance of the sub oil return pipe 22b. Therefore, once the steady state is entered, the amount obtained by subtracting the amount used for refueling of the expander 1 from the oil captured by the oil separator 26, that is, the amount of oil that has been originally taken out from the main compressor 5, is returned to the main oil. What is necessary is just to return to the inlet side of the main compressor 5 from the pipe | tube 22a. Adjustment of the amount of oil returned from the main oil return pipe 22 a to the suction side of the main compressor 5 is performed by the variable throttle 27.

  As described above, when the oil supply to the two places of the expander 1 and the motor driven main compressor 5 is performed by the oil return from the oil separator 26 provided on the discharge side of the main compressor 5, this embodiment is used. According to the configuration, the following effects can be obtained. That is, due to the pressure difference between the one end 78b and the other end 78c of the oil hole 78a in the shaft 78, each bearing portion (the expansion side bearing portion 51c, the sub compression side bearing portion 61c, and the swinging portion is connected via the oil hole 78a and the bearing oil supply hole 78d. Since the differential pressure oil is supplied to the dynamic bearing portion 52d), the oil leveling pipe for sharing the oil level in the sealed container of the main compressor 5 and the sealed container 4 of the expander 1 which are the main oil reservoirs and There is no need for a pressure equalizing pipe, and there are no restrictions on the installation position. In addition, it is possible to supply oil without using an oil supply pump.

  In addition, in the first space 4a filled with oil, there is no moving member such as a balance weight other than the end of the shaft 78 facing. Therefore, the oil supply from the oil hole 78a in the shaft 78 to each bearing portion and each sliding portion can be performed without accompanying loss due to stirring of the filled oil, movement inhibition due to oil resistance, and the like. Thus, a sub-compressor integrated expander with high recovery efficiency and stable operation can be obtained.

  Further, the sub-compression mechanism 3 performs the compression operation in parallel with the main compressor 5 from the low pressure to the intermediate pressure, so that the loss of matching between the flow rate and the power accompanying the recovery of the expansion power can be minimized.

  In addition, since the volume flow rate is adjusted by the main compression / sub-compression split on the compression side, energy efficiency can be improved compared to a refrigeration cycle apparatus that performs volume flow adjustment by expansion side bypass or pre-expansion. Yes, it can contribute to energy saving.

  In addition, in conventional refrigeration cycle equipment that requires oil level control, if the circuit is long due to the extension piping, oil may stay in the container other than the main compressor and expander, or the oil may move. If it takes a long time, the oil level balance cannot be maintained transiently, and there is a possibility that the lubricating oil in either the main compressor or the expander is insufficient. In contrast, in this embodiment, the variable throttle 27 provided in the main oil return pipe 22a is adjusted so that the amount of oil returned from the oil separator 26 to the suction side of the main compressor 5 is adjusted appropriately. Can be supplied stably. Therefore, it is possible to prevent the oil from being depleted and to prevent seizure due to insufficient lubrication. As a result, the life can be extended.

  Further, since the oil separated by the oil separator 26 is directly supplied to the main compressor 5 or the expander 1 without passing through the circuit between the main compression mechanism 7 and the expander 1, the oil is contained in the refrigerant. Decrease in heat exchange performance due to the presence of the mixture can be suppressed and a highly efficient refrigeration system can be obtained.

  Moreover, since CO2 is used as the refrigerant, a refrigeration cycle apparatus having the above-described effects can be obtained without destroying the global environment.

DESCRIPTION OF SYMBOLS 1 Expander, 2 Expansion mechanism, 3 Sub compression mechanism, 4 Airtight container, 4a 1st space, 4b
2nd space, 4c Oil supply hole, 4d Intake hole, 5 Main compressor, 6 Motor, 7 Main compression mechanism, 11 Radiator, 12 Evaporator, 14 Pre-expansion valve, 15 Expansion suction pipe, 16 Expansion discharge pipe, 19 Sub Compression suction pipe, 20 sub-compression discharge pipe, 22a main oil return pipe, 22b sub oil return pipe, 26 oil separator, 27 variable throttle, 32 discharge valve, 33 valve space, 34 plate, 35 expansion suction port, 36 expansion discharge Port, 37 Oil supply pipe, 40 Sub compression discharge port, 51 Expansion fixed scroll, 51a Base plate, 51b Spiral tooth, 51c Expansion side bearing part, 51d Expansion suction flow path, 51e Expansion discharge flow path, 52 Swing scroll, 52a table Plate, 52b Expansion side spiral tooth, 52c Sub compression side spiral tooth, 52d Oscillating bearing, 52e High pressure introduction hole, 61 Sub compression fixed scroll, 61a Base plate, 61b Spiral tooth 61c Sub-compression side bearing part, 61d Sub-compression suction communication path, 61e Orbiting scroll motion space, 61f Sub-compression discharge flow path, 72a Eccentric seal, 72b Eccentric seal, 73 Concentric seal, 77 Oldham ring, 78 Shaft, 78a Oil hole 78b one end, 78c other end, 78d bearing oil supply hole, 79a balance weight (anti-oscillation eccentric side), 79b balance weight (oscillation eccentric side), 80 piping, 81 piping, 82 check valve.

Claims (3)

An expansion mechanism for recovering power by expanding the refrigerant;
A compression mechanism coupled to the expansion mechanism via a shaft and compressing the refrigerant by the power recovered by the expansion mechanism;
A container for accommodating the expansion mechanism and the compression mechanism;
The inside of the container is divided into a first space in which high-pressure oil is supplied from an oil separator through an oil supply hole that penetrates the container, and a second space that has a lower pressure atmosphere than the first space. In the second space, a balance weight supported by the shaft and rotating integrally with the shaft is disposed,
The shaft passes through the shaft in the axial direction, one end opens into the first space, the other end opens into the second space, and the shaft extends from the oil supply passage in the radial direction of the shaft. Bearing oil supply holes communicating with the bearing portions for the shafts of the expansion mechanism and the compression mechanism,
The expander according to claim 1, wherein oil in the first space is supplied to each of the bearing portions through the bearing oil supply hole from the one end of the oil supply passage. A main compression mechanism for compressing the refrigerant;
An oil separator that separates the refrigerant that has passed through the main compression mechanism and the oil contained in the refrigerant;
A radiator that cools the refrigerant that has passed through the main compression mechanism;
An expander for expanding the refrigerant that has passed through the radiator;
An evaporator for evaporating the refrigerant expanded by the expander,
These are sequentially connected by piping, and the refrigerant is circulated.
The expander is configured by the expansion mechanism according to claim 1, and a part of the refrigerant from the evaporator toward the main compression mechanism is supplied to the compression mechanism of the expander and compressed, and then the main compression Supply it while the mechanism is compressing,
A main oil return pipe that returns oil separated by the oil separator to a pipe between the main compression mechanism and the evaporator, and oil separated by the oil separator is supplied to the oil supply hole of the container. A refrigeration cycle apparatus comprising a sub oil return pipe for feeding.   The refrigeration cycle apparatus according to claim 2, wherein the main oil return pipe has a variable throttle.

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